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Sample records for pressure liquid chromatography-tandem

  1. Determination of tetracycline residues in soil by pressurized liquid extraction and liquid chromatography tandem mass spectrometry.

    PubMed

    Andreu, Vicente; Vazquez-Roig, Pablo; Blasco, Cristina; Picó, Yolanda

    2009-07-01

    An optimized extraction and cleanup method for the analysis of chlortetracycline (CTC), doxycycline (DC), oxytetracycline (OTC) and tetracycline (TC) in soil is presented. Soil extraction in a pressurized liquid extraction system, followed by extract clean up using solid-phase extraction (SPE) and tetracycline determination by liquid chromatography tandem mass spectrometry (LC-MS/MS) provided appropriate efficiency and reproducibility. Different dispersing agents and solvents for soil extraction and several SPE cartridges for cleanup were compared. The best extraction results were obtained using ethylenediamine tetraacetic acid-treated sand as dispersing agent, and water at 70 degrees C. The most effective cleanup was obtained using Strata-X sorbent in combination with a strong anion exchange cartridge. Recoveries ranged from 71% to 96% and precision, as indicated by the relative standard deviations, was within the range of 8-15%. The limits of quantification (LOQs) by using LC-MS/MS, based on signal-to-noise ratio (S/N) of 10, ranged from 1 microg kg(-1) for TC to 5 microg kg(-1) for CTC. These results pointed out that this technique is appropriate to determine tetracyclines in soils. Analysis of 100 samples taken in the Valencian Community revealed that, in soil, up to 5 microg kg(-1) CTC, 15 microg kg(-1) OTC, 18 microg kg(-1) TC, and 12 microg kg(-1) DC could be detected. Detection of the analytes in several samples, which typify great part of the Spanish agricultural soils, should be outlined as most important result of this study. PMID:19205670

  2. Determination of antibiotics (tetracyclines and sulfonamides) in biosolids by pressurized liquid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Pamreddy, Annapurna; Hidalgo, Manuela; Havel, Josef; Salvadó, Victòria

    2013-07-12

    A robust and sensitive analytical method is developed to quantitatively determine tetracyclines and sulfonamides, two major antibiotic classes, in sewage sludge. The antibiotic agents, oxytetracycline, tetracycline, dioxycycline, chlorotetracycline, sulfathiazole, sulfapyridine, sulfamethazine and sulfamethoxazole, were extracted using pressurized liquid extraction (PLE) with citric acid at pH 3 and methanol (1:1 v/v). Clean-up of the extracts was performed by solid phase extraction (SPE) with hydrophilic-lipophilic balance cartridges. Identification and quantification of the compounds is by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring (MRM) mode. High recoveries ranging from 90.4 to 99.9% for sulfonamides and 96.2 to 100.9% for the tetracyclines are obtained. Method detection limits (MDLs) range from 0.6 to 4.2 ng/g for sulfonamides and 3.2 to 13 ng/g for tetracyclines. After validation, the method is applied to the analysis of sludges collected from different WWTPs in Spain. PMID:23755983

  3. Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

    PubMed

    Farhan, Nashid; Fitzpatrick, Sean; Shim, Yun M; Paige, Mikell; Chow, Diana Shu-Lian

    2016-09-01

    4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization. With the advent of atmospheric pressure photoionization (APPI) technique, many hydrophobic compounds have been demonstrated to ionize by charge transfer reactions. In this study, a highly sensitive ultrapressure liquid chromatography tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for the quantifications of 4-MDM in rat plasma has been developed and validated. 4-MDM was extracted from the plasma by solid phase extraction (SPE) and separated chromatographically using a reverse phase C8 column. The photoionization (PI) was achieved by introducing anisole as a dopant to promote the reaction of charge transfer. The assay with a linear range of 5 (LLOQ)-400ngmL(-1) met the regulatory requirements for accuracy, precision and stability. The validated assay was employed to quantify the plasma concentrations of 4-MDM after an oral dosing in Sprague Dawley (SD) rats. PMID:27232150

  4. Rapid analysis of aflatoxin M1 in milk using dispersive liquid-liquid microextraction coupled with ultrahigh pressure liquid chromatography tandem mass spectrometry.

    PubMed

    Campone, Luca; Piccinelli, Anna Lisa; Celano, Rita; Russo, Mariateresa; Rastrelli, Luca

    2013-10-01

    A simple, rapid, and sensitive method based on simultaneous protein precipitation and extraction of aflatoxin M1 (AFM1) followed by dispersive liquid-liquid microextraction (DLLME) and ultrahigh pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis was developed for the determination of AFM1 in milk samples. In order to precipitate the proteins and extract AFM1 from milk, a sample pretreatment using acetonitrile and NaCl as the extraction/denaturant solvent and salting-out agent, respectively, was optimised. Subsequently, the acetonitrile (upper) phase, containing AFM1, was used as the disperser solvent in DLLME, and extractant (chloroform) and water were added in turn to the extract to perform the DLLME process. The main parameters affecting the extraction efficiency of the whole analytical procedure, such as acetonitrile volume, amount of salt, type and volume of extractant and water volume, were carefully optimised by experimental design. Under optimum conditions, the developed method provides an enrichment factor of 33 and detection and quantification limits (0.6 and 2.0 ng kg(-1), respectively) below the maximum levels imposed by current regulations for AFM1 in milk and infant milk formulae. Recoveries (61.3-75.3%) and repeatability (RSD < 10, n = 3), tested in different types of milk at four AFM1 levels, met the performance criteria required by EC Regulation No. 401/2006. Moreover, the matrix effect on the signal intensity of the analyte was negligible. The proposed method provides a rapid extraction and an accurate determination of AFM1 in milk and formula milk using a simple and inexpensive sample preparation procedure. PMID:23942569

  5. Development of a liquid chromatography-tandem mass spectrometry with pressurized liquid extraction method for the determination of benzimidazole residues in edible tissues.

    PubMed

    Chen, Dongmei; Tao, Yanfei; Zhang, Huahai; Pan, Yuanhu; Liu, Zhenli; Huang, Lingli; Wang, Yulian; Peng, Dapeng; Wang, Xu; Dai, Menghong; Yuan, Zonghui

    2011-06-01

    A confirmatory and quantitative method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with a pressure liquid extraction (PLE) was developed for the determination of 11 benzimidazole and 10 metabolites of albendazole, fenbendazole and mebendazole in the muscles and livers of swine, cattle, sheep and chicken. For sample preparation, we used an automated technique of PLE method. The optimum extraction conditions were obtained using an 11 ml Accelerated Solvent Extraction (ASE) cells, acetonitrile/hexane as the extraction solvent. HPLC analysis was performed on a C18 column with gradient elution using acetonitrile and 5 mmol l(-1) formic ammonium as mobile phase. The analytes were detected in the positive ion multiple reaction monitoring (MRM) mode by the LC-ESI-MS/MS analysis. The recoveries of benzimidazole (BZDs) spiked at the levels of 0.5 μg kg(-1) ranged from 70.1% to 92.7%; the between-day relative standard deviations were no more than 10%. The limits of quantification were 0.02-0.5 μg kg(-1). The optimized method was successfully applied to monitor real samples containing BZDs, demonstrating the method to be simple, fast, robust and suitable for identification and quantification of BZDs residues in animal products. PMID:21543271

  6. Ultra-high-pressure liquid chromatography tandem mass spectrometry method for the determination of 9 organophosphate flame retardants in water samples

    PubMed Central

    Lorenzo, María; Campo, Julián; Picó, Yolanda

    2016-01-01

    Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation. Ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-QqQ-MS/MS) has become the most promising platform, already applied successfully for analysis of selected PFRs in some environmental matrices like water and wastewater. However, the presence of some interferences from the dissolvent, the equipment and the used materials should be taken into account. The procedure involves: • The first determination of PFRs by UHPLC-QqQ-MS/MS using a trap column to distinguish the interferences coming from the instrument and mobile phases. • The optimization of the LC separation to distinguish all target compounds and their interferences. • This method coupled to a solid-phase extraction (SPE) improve the detection and quantification of PFRs. PMID:27222824

  7. Trace-level determination of sweeteners in sewage sludge using selective pressurized liquid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Arbeláez, Paula; Borrull, Francesc; Maria Marcé, Rosa; Pocurull, Eva

    2015-08-21

    The occurrence of sweeteners in the environment has become a matter of concern due to the possibility of adverse effects on human health and wildlife species. One of the routes by which sweeteners enter the environment is through sewage sludge. Therefore, a method was developed with a selective-pressurized liquid extraction (S-PLE) followed by liquid chromatography-tandem mass spectrometry for the simultaneous determination of eight sweeteners in sewage sludge. The chromatographic separation was achieved in less than ten minutes using an amide polar-embedded reversed-phase column. Due to the high matrix effect present in the sample, an extensive study was conducted in order to overcome this issue, with C18 in-cell and solid-phase extraction (Oasis HLB) as a clean-up method. S-PLE/SPE recoveries at two levels of concentration (50μg/kg and 1000μg/kg in dry weight (d.w.), n=5) were higher than 61%. Repeatability and reproducibility at the same concentrations (%RSD, n=5) were lower than 11% and 16%, respectively. The limits of detection were 10μg/kg (d.w) for all compounds, except for cyclamate (5μg/kg (d.w.)). The method was successfully applied to sewage sludge samples from three sewage treatment plants located in Catalonia (Spain). Of the eight compounds, five were determined in all of the samples analysed, with acesulfame and saccharine being recorded at the highest concentrations of up to 481μg/kg and 591μg/kg (d.w.), respectively. PMID:26199101

  8. Analysis of vitamin K1 in fruits and vegetables using accelerated solvent extraction and liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Jäpelt, Rie Bak; Jakobsen, Jette

    2016-02-01

    The objective of this study was to develop a rapid, sensitive, and specific analytical method to study vitamin K1 in fruits and vegetables. Accelerated solvent extraction and solid phase extraction was used for sample preparation. Quantification was done by liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization in selected reaction monitoring mode with deuterium-labeled vitamin K1 as an internal standard. The precision was estimated as the pooled estimate of three replicates performed on three different days for spinach, peas, apples, banana, and beetroot. The repeatability was 5.2% and the internal reproducibility was 6.2%. Recovery was in the range 90-120%. No significant difference was observed between the results obtained by the present method and by a method using the same principle as the CEN-standard i.e. liquid-liquid extraction and post-column zinc reduction with fluorescence detection. Limit of quantification was estimated to 0.05 μg/100g fresh weight. PMID:26304366

  9. Optimization of an analytical methodology for the simultaneous determination of different classes of ultraviolet filters in cosmetics by pressurized liquid extraction-gas chromatography tandem mass spectrometry.

    PubMed

    Vila, Marlene; Lamas, J Pablo; Garcia-Jares, Carmen; Dagnac, Thierry; Llompart, Maria

    2015-07-31

    A methodology based on pressurized liquid extraction (PLE) followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) has been developed for the simultaneous analysis of different classes of UV filters including methoxycinnamates, benzophenones, salicylates, p-aminobenzoic acid derivatives, and others in cosmetic products. The extractions were carried out in 1mL extraction cells and the amount of sample extracted was only 100mg. The experimental conditions, including the acetylation of the PLE extracts to improve GC performance, were optimized by means of experimental design tools. The two main factors affecting the PLE procedure such as solvent type and extraction temperature were assessed. The use of a matrix matched approach consisting of the addition of 10μL of diluted commercial cosmetic oil avoided matrix effects. Good linearity (R(2)>0.9970), quantitative recoveries (>80% for most of compounds, excluding three banned benzophenones) and satisfactory precision (RSD<10% in most cases) were achieved under the optimal conditions. The validated methodology was successfully applied to the analysis of different types of cosmetic formulations including sunscreens, hair products, nail polish, and lipsticks, amongst others. PMID:26091782

  10. Determination of estrogenic compounds in wastewater using liquid chromatography-tandem mass spectrometry with electrospray and atmospheric pressure photoionization following desalting extraction.

    PubMed

    Chen, Hsin-Chang; Kuo, Han-Wen; Ding, Wang-Hsien

    2009-01-01

    Two complementary LC-MS ionization methods, electrospray (ESI) and atmospheric pressure photoionization (APPI), have been optimized to determine three natural estrogenic compounds (estrone, 17beta-estradiol and estriol) and two synthetic estrogenic compounds (17alpha-ethynylestradiol and diethylstilbestrol) in the influent and effluent of wastewater treatment plants (WWTPs). The wastewater samples were first subjected to solid-phase extraction coupled with desalting extraction to remove matrix interference. The analytes were then detected using liquid chromatography-tandem mass spectrometry (LC-MS-MS) with ESI and dopant-assisted (DA) APPI to evaluate the ion suppression effect and to complement the detection and quantification of estrogenic compounds in complex wastewater samples. The average ion suppression factors for the extracts of the WWTP influent analyzed using ESI and APPI were 52+/-5% and 27+/-7%, respectively. The sensitivity and ionization efficiency of the LC-ESI-MS-MS system decreased dramatically when a complex matrix was present in the WWTP influent sample. Estrogenic compounds could be detected in the WWTP influent and effluent samples at concentrations below the parts-per-billion level. The lower detection limits obtained when using ESI and the higher matrix tolerance of the APPI method allowed the complete quantification of estrogenic compounds in very complex samples in a complementary manner. PMID:18996561

  11. Ultra-high-pressure liquid chromatography tandem mass spectrometry method for the determination of 9 organophosphate flame retardants in water samples.

    PubMed

    Lorenzo, María; Campo, Julián; Picó, Yolanda

    2016-01-01

    Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation. Ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-QqQ-MS/MS) has become the most promising platform, already applied successfully for analysis of selected PFRs in some environmental matrices like water and wastewater. However, the presence of some interferences from the dissolvent, the equipment and the used materials should be taken into account. The procedure involves: •The first determination of PFRs by UHPLC-QqQ-MS/MS using a trap column to distinguish the interferences coming from the instrument and mobile phases.•The optimization of the LC separation to distinguish all target compounds and their interferences.•This method coupled to a solid-phase extraction (SPE) improve the detection and quantification of PFRs. PMID:27222824

  12. Dopant-assisted atmospheric pressure photoionization of patulin in apple juice and apple-based food with liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Kai; Wong, Jon W; Mai, Huy; Trucksess, Mary W

    2014-05-01

    A dopant-assisted atmospheric pressure photoionization (APPI) with liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to determine patulin in apple juice and apple-based food. Different dopants, dopant flow rates, and LC separation conditions were evaluated. Using toluene as the dopant, the LC-APPI-MS/MS method achieved a linear calibration from 12.5 to 2000 μg/L (r(2) > 0.99). Matrix-dependent limits of quantitation (LOQs) were from 8 μg/L (solvent) to 12 μg/L (apple juice). [(13)C]-Patulin-fortified apple juice samples were directly analyzed by the LC-APPI-MS/MS method. Other apple-based food was fortified with [(13)C]-patulin, diluted using water (1% formic acid), centrifuged, and filtered, followed by LC-APPI-MS/MS analysis. In clear apple juice, unfiltered apple cider, applesauce, and apple-based baby food, average recoveries were 101 ± 6% (50 μg/kg), 103 ± 5% (250 μg/kg), and 102 ± 5% (1000 μg/kg) (av ± SD, n = 16). Using the suggested method, patulin was detected in 3 of 30 collected market samples with concentrations ranging from

  13. New perspective on the determination of flame retardants in sewage sludge by using ultrahigh pressure liquid chromatography-tandem mass spectrometry with different ion sources.

    PubMed

    Mascolo, G; Locaputo, V; Mininni, G

    2010-07-01

    Analysis of 11 polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A bis 2,3-dibromopropylether (TBBPA-bis), tetrachlorobisphenol A (TCBPA), tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) was optimized by ultrahigh pressure liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) operating in negative ion (NI) mode. Electrospray ionization (ESI), atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) sources were tested and for PBDEs APCI gave higher sensitivity than APPI while for TBBPA-bis APCI and APPI showed similar performance. ESI was the best option for TCBPA, TBBPA and HBCDs. Detection limits were between 20 and 59 fg for the compounds analyzed by ESI, 0.10 and 0.72 pg for PBDEs and 6 pg for TBBPA-bis. The matrix effect of sewage sludge extract was also tested showing negligible ion suppression for APCI and an increase of the background level of all investigated pollutants leading to a worsening of the limits of quantification by a factor between 1.2 and 3.3. The UPLC-APCI/MS/MS method for PBDEs, after pressurized liquid extraction (PLE), was validated by comparison with the concentration values from the NIST 1944 standard reference material. The advantages of the methods include low detection limits, PBDE congeners specificity using selected multiple reaction monitoring (MRM) transitions, and the absence of thermal degradation of higher PBDE congeners, especially BDE-209. The methods were applied for the determination of the above reported flame retardants in sewage sludge in order to get more information about the degradation on PBDEs (in particular BDE-209) during municipal wastewater treatments. PMID:20564801

  14. Repeatability of gradient ultrahigh pressure liquid chromatography-tandem mass spectrometry methods in instrument-controlled thermal environments.

    PubMed

    Grinias, James P; Wong, Jenny-Marie T; Kennedy, Robert T

    2016-08-26

    The impact of viscous friction on eluent temperature and column efficiency in liquid chromatography is of renewed interest as the need for pressures exceeding 1000bar to use with columns packed with sub-2μm particles has grown. One way the development of axial and radial temperature gradients that arise due to viscous friction can be affected is by the thermal environment the column is placed in. In this study, a new column oven integrated into an ultrahigh pressure liquid chromatograph that enables both still-air and forced-air operating modes is investigated to find the magnitude of the effect of the axial thermal gradient that forms in 2.1×100mm columns packed with sub-2μm particles in these modes. Temperature increases of nearly 30K were observed when the generated power of the column exceeded 25W/m. The impact of the heating due to viscous friction on the repeatability of peak capacity, elution time, and peak area ratio to an internal standard for a gradient UHPLC-MS/MS method to analyze neurotransmitters was found to be limited. This result indicates that high speed UHPLC-MS/MS gradient methods under conditions of high viscous friction may be possible without the negative effects typically observed with isocratic separations under similar conditions. PMID:27457561

  15. Determination of pesticides in milk-based infant formulas by pressurized liquid extraction followed by gas chromatography tandem mass spectrometry.

    PubMed

    Mezcua, M; Repetti, M R; Agüera, A; Ferrer, C; García-Reyes, J F; Fernández-Alba, A R

    2007-11-01

    An efficient and selective automated analytical method for the determination and quantification of a selected group of 12 organochlorine and organophosphorous pesticides in milk-based infant formulas has been developed. The samples were extracted by pressurized liquid extraction (PLE) and analysed using GC-MS/MS. The use of alumina as the fat retainer in the PLE extraction cell, together with the application of an injector temperature program during the GC injection process, avoided typical matrix interferences without the application of additional cleanup steps. Mean recoveries of between 70 and 110% were achieved for most of the compounds, except for chlorpyrifos methyl (50%), vinclozoline (48%), fenitrothion (56%) and procymidone (53%), with relative standard deviations ranging from 9 to 17%. Low limits of quantification were obtained for the studied compounds, from 0.01 to 2.6 microg kg(-1), thus guaranteeing their accurate determination within the rigorous requirements established for baby food. The validated method was applied to a pilot monitoring study in Spain. Twenty five samples of different brands of powdered infant formulas were obtained from supermarkets. Positive findings of endosulfan I, endosulfan II, fenitrothion, chlorpyrifos ethyl and bifenthrin were detected at concentrations ranging from 0.03 to 5.03 microg kg(-1). PMID:17680236

  16. Construction of an Ultrahigh Pressure Liquid Chromatography-Tandem Mass Spectral Library of Plant Natural Products and Comparative Spectral Analyses.

    PubMed

    Lei, Zhentian; Jing, Li; Qiu, Feng; Zhang, Hua; Huhman, David; Zhou, Zhiqin; Sumner, Lloyd W

    2015-07-21

    A plant natural product tandem mass spectral library has been constructed using authentic standards and purified compounds. Currently, the library contains 1734 tandem mass spectra for 289 compounds, with the majority (76%) of the compounds being plant phenolics such as flavonoids, isoflavonoids, and phenylpropanoids. Tandem mass spectra and chromatographic retention data were acquired on a triple quadrupole mass spectrometer coupled to an ultrahigh pressure liquid chromatograph using six different collision energies (CEs) (10-60 eV). Comparative analyses of the tandem mass spectral data revealed that the loss of ring substituents preceded the C-ring opening during the fragmentation of flavonoids and isoflavonoids. At lower CE (i.e., 10 and 20 eV), the flavonoids and isoflavonoid central ring structures typically remained intact, and fragmentation was characterized by the loss of the substituents (i.e., methyl and glycosyl groups). At higher CE, the flavonoid and isoflavonoid core ring systems underwent C-ring cleavage and/or rearrangement depending on the structure, particularly hydroxylation patterns. In-source electrochemical oxidation was observed for phenolics that had ortho-diphenol moieties (i.e., vicinal hydroxyl groups on the aromatic rings). The ortho-diphenols were oxidized to ortho-quinones, yielding an intensive and, in most cases, a base ion peak corresponding to a [(M - 2H) - H](-) ion in their mass spectra. The library also contains reverse-phase retention times, allowing for the construction, validation, and testing of an artificial neural network retention prediction of other flavonoids and isoflavonoids not contained within the library. The library is freely available for nonprofit, academic use and it can be downloaded at http://www.noble.org/apps/Scientific/WebDownloadManager/DownloadArea.aspx. PMID:26107650

  17. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of hallucinogenic drugs in hair of psychedelic plants and mushrooms consumers.

    PubMed

    Pichini, Simona; Marchei, Emilia; García-Algar, Oscar; Gomez, Arelis; Di Giovannandrea, Rita; Pacifici, Roberta

    2014-11-01

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of mescaline, N,N-dimethyltryptamine, psilocin, psilocybin, salvinorin A in hair of consumers of psychedelic vegetal material such peyote or trichocereus cacti, psilocybe mushrooms, Salvia divinorum or psychedelic beverage ayahuasca. After hair washing with methyl alcohol and diethyl ether and subsequent addition of mescaline-d9 and 3,4-methylenedioxypropylamphetamine as internal standards, hair samples were treated with 250μl VMA-T M3 reagent for 1h at 100°C. After cooling, 100μl M3 extract were diluted with 400μl water and a volume of 10μl was injected into chromatographic system. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.03-0.05ng/mg depending on analyte under investigation) to 10ng/mg hair, with an intra- and inter-assay imprecision and inaccuracy always less than 15% and an analytical recovery between 79.6% and 97.4%, depending on the considered analyte. Using the validated method, mescaline was found in concentration range of 0.08-0.13ng/mg in hair of peyote smokers, 3.2ng salvinorin A per mg hair were determined in hair from a S. divinorum smoker, 5.6ng N,N-dimethyltryptamine per mg hair from an ayahuasca user and finally 0.8ng psilocybin per ng hair of a psilocybe consumer. PMID:25171488

  18. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of antidepressant and anxiolytic drugs in neonatal meconium and maternal hair.

    PubMed

    Pichini, Simona; Cortes, Laura; Marchei, Emilia; Solimini, Renata; Pacifici, Roberta; Gomez-Roig, Maria Dolores; García-Algar, Oscar

    2016-01-25

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of 22 antidepressant and anxiolytic drugs ad metabolites in the three consecutive maternal hair segments representing the pregnancy trimesters and paired neonatal meconium samples. After hair washing with methyl alcohol and diethyl ether and subsequent addition of internal standards, hair samples were treated with 500 μl VMA-T M3 reagent for 1h at 100 °C. After cooling, 100 μl M3 extract were diluted with 400 μl water and a volume of 10 μl was injected into chromatographic system. Meconium samples were firstly treated with 1 ml methyl alcohol and the organic layer back-extracted twice with 1.5 ml of a mixture of ethylacetate:hexane (80:20, v/v). Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.05-1 ng/mg hair and 5-25 ng/g meconium depending on analyte under investigation;) to 10 ng/mg hair and 1000 ng/g meconium, with an intra- and inter-assay imprecision and inaccuracy always less than 20% and an analytical recovery between 66.6% and 95.3%, depending on the considered analyte and biological matrix. Using the validated method, 7 mothers were found positive to one or more hair segments and 5 meconium samples were found positive to one or more antidepressant and anxiolytic drugs, assessing prenatal exposure to these drugs following maternal consumption in one or more pregnancy trimesters. PMID:26512994

  19. Simultaneous determination of some phthalate metabolites, parabens and benzophenone-3 in urine by ultra high pressure liquid chromatography tandem mass spectrometry.

    PubMed

    Dewalque, Lucas; Pirard, Catherine; Dubois, Nathalie; Charlier, Corinne

    2014-02-15

    Phthalates, parabens and 2-hydroxy-4-methoxybenzophenone or benzophone-3 are thought to act as endocrine disrupting chemicals, being able to disrupt the endocrine balance and therefore able to lead to some hormonal diseases. Numerous large-scale biomonitoring studies have detected the biomarkers of these compounds in more than 75% of the general population. To assess the exposure to these chemicals, we developed an analytical method based on a Solid Phase Extraction (SPE) prior to ultra high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous measurement of seven phthalate metabolites (monobenzyl phthalate, mono-n-butyl phthalate, mono-iso-butyl phthalate, mono-2-ethylhexyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, mono-2-ethyl-5-oxohexyl phthalate, monoethyl phthalate), four parabens (methyl paraben, ethyl paraben, n-propyl paraben, n-butyl parabens) and benzophenone-3 in human urine. The distinction between unconjugated, glucuro- and sulfoconjugated forms was achieved using different enzymatic hydrolyses. The whole procedure was validated according to the total error approach, and was demonstrated to be linear (regression coefficient ranging from 0.987 to 0.998) and accurate (inter and intra assay precision <17.71%, relative bias <5.87%) in the dosing range of concentrations. The limits of quantification (LOQs) obtained ranged between 0.30 and 1.23ng/ml depending on the analyte. The reliability of the method was proven in passing successfully the German External Quality Assessment Scheme (G-EQUAS). Moreover, the urine from 25 volunteers were analyzed for the determination of glucuro-, sulfo- and free species separately. Phthalate metabolites, parabens and benzophenone-3 were positively detected in almost all urine samples, with detection rates ranging from 40 to 100%. Levels measured ranged from

  20. An improved method for retrospective quantification of sulfur mustard exposure by detection of its albumin adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Liu, ChangCai; Liang, LongHui; Xiang, Yu; Yu, HuiLan; Zhou, ShiKun; Xi, HaiLing; Liu, ShiLei; Liu, JingQuan

    2015-09-01

    Sulfur mustard (HD) adduct to human serum albumin (ALB) at Cys-34 residue has become an important and long-term retrospective biomarker of HD exposure. Here, a novel, sensitive, and convenient approach for retrospective quantification of HD concentration exposed to plasma was established by detection of the HD-ALB adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with a novel non-isotope internal standard (IS). The HD-ALB adduct was isolated from HD-exposed plasma with blue Sepharose. The adduct was digested with proteinase K to form sulfur-hydroxyethylthioethyl ([S-HETE])-Cys-Pro-Phe tripeptide biomarker. The tripeptide adduct could be directly analyzed by UHPLC-MS/MS without an additional solid phase extraction (SPE), which was considered as a critical procedure in previous methods. The easily available 2-chloroethyl ethylsulfide (2-CEES) as HD surrogate was first reported to be used as IS in place of traditional d8-HD for quantification of HD exposure. Furthermore, 2-CEES was also confirmed to be a good IS alternative for quantification of HD exposure by investigation of product ion spectra for their corresponding tripeptide adducts which exhibited identical MS/MS fragmentation behaviors. The method was found to be linear between 1.00 and 250 ng•mL(-1) HD exposure (R(2)>0.9989) with precision of <4.50% relative standard deviation (%RSD), accuracy range between 96.5% and 114%, and a calculated limit of detection (LOD) of 0.532 ng•mL(-1). The lowest reportable limit (LRL) is 1.00 ng•mL(-1), over seven times lower than that of the previous method. The entire method required only 0.1 mL of plasma sample and took under 7 h without special sample preparation equipment. It is proven to be a sensitive, simple, and rugged method, which is easily applied in international laboratories to improve the capabilities for the analysis of biomedical samples related to verification of the Chemical Weapon Convention (CWC). PMID

  1. A fully automated method for simultaneous determination of aflatoxins and ochratoxin A in dried fruits by pressurized liquid extraction and online solid-phase extraction cleanup coupled to ultra-high-pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Campone, Luca; Piccinelli, Anna Lisa; Celano, Rita; Russo, Mariateresa; Valdés, Alberto; Ibáñez, Clara; Rastrelli, Luca

    2015-04-01

    According to current demands and future perspectives in food safety, this study reports a fast and fully automated analytical method for the simultaneous analysis of the mycotoxins with high toxicity and wide spread, aflatoxins (AFs) and ochratoxin A (OTA) in dried fruits, a high-risk foodstuff. The method is based on pressurized liquid extraction (PLE), with aqueous methanol (30%) at 110 °C, of the slurried dried fruit and online solid-phase extraction (online SPE) cleanup of the PLE extracts with a C18 cartridge. The purified sample was directly analysed by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for sensitive and selective determination of AFs and OTA. The proposed analytical procedure was validated for different dried fruits (vine fruit, fig and apricot), providing method detection and quantification limits much lower than the AFs and OTA maximum levels imposed by EU regulation in dried fruit for direct human consumption. Also, recoveries (83-103%) and repeatability (RSD < 8, n = 3) meet the performance criteria required by EU regulation for the determination of the levels of mycotoxins in foodstuffs. The main advantage of the proposed method is full automation of the whole analytical procedure that reduces the time and cost of the analysis, sample manipulation and solvent consumption, enabling high-throughput analysis and highly accurate and precise results. PMID:25694147

  2. High-throughput multiclass method for antibiotic residue analysis by liquid chromatography-tandem mass spectrometry.

    PubMed

    Chico, J; Rúbies, A; Centrich, F; Companyó, R; Prat, M D; Granados, M

    2008-12-12

    A simple and rapid method has been developed for the residue analysis of 39 antibiotics (tetracyclines, quinolones, penicillins, sulfonamides and macrolides) in foodstuffs of animal origin. The method combines an effective extraction technique, which uses water-methanol as extracting solvent, with ultra-high-pressure liquid chromatography-tandem mass spectrometry, allowing both confirmation and quantification in a single chromatographic run. The multiresidue method has been validated in chicken muscle matrix according to European Union Decision 2002/657/EC. It has been implemented as a routine method in a Public Health Laboratory, instead of the five plates test and LC methods previously used. PMID:18992888

  3. Development of a liquid chromatography-tandem mass spectrometry with pressurized liquid extraction for determination of glucocorticoid residues in edible tissues.

    PubMed

    Chen, Dongmei; Tao, Yanfei; Liu, Zhaoying; Zhang, Huahai; Liu, Zhenli; Wang, Yulian; Huang, Lingli; Pan, Yuanhu; Peng, Dapeng; Dai, Menghong; Wang, Xu; Yuan, Zonghui

    2011-01-15

    A multi-residues method using pressurized liquid extraction (PLE) and liquid chromatography combined with mass spectrometry (LC-MS/MS) has been developed for determination of eight glucocorticoids (prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone, fludrocortisone) in muscle of swine, cattle, and sheep. Parameters affecting PLE extraction including extraction solvent, extraction temperature, extraction pressure and extraction cycles were optimized. The optimized method employed 11 ml extraction cells, hexane-ethyl acetate (50:50, v/v) as extraction solvent, 1500 psi of extraction pressure and 50°C of extraction temperature. The samples were detected by LC-ESI-MS/MS in negative mode with selected reaction monitoring (SRM) mode. The recovery of glucocorticoids spiked at levels of 0.5-6 μg kg(-1) ranged from 70.1% to 103.1%; the between-day relative standard deviations were no more than 9.6%. The limits of quantification were 0.5-2 μg kg(-1) in muscle. The results demonstrated that the method is simple, fast, robust, and suitable for identification and quantification of glucocorticoids residues in foods of animal origin. PMID:21195680

  4. Determination of dalcetrapib by liquid chromatography-tandem mass spectrometry.

    PubMed

    Heinig, Katja; Bucheli, Franz; Kuhlmann, Olaf; Zell, Manfred; Pähler, Axel; Zwanziger, Elke; Gross, Günter; Tardio, Joseph; Ishikawa, Tomohiro; Yamashita, Tomoko

    2012-07-01

    The cholesteryl ester transfer protein modulator dalcetrapib is currently under development for the prevention of dyslipidemia and cardiovascular disease. Dalcetrapib, a thioester, is rapidly hydrolyzed in vivo to the corresponding thiophenol which in turn is further oxidized to the dimer and mixed disulfides (where the thiophenol binds to peptides, proteins and other endogenous thiols). These forms co-exist in an oxidation-reduction equilibrium via the thiol and cannot be stabilized without influencing the equilibrium, hence specific determination of individual components, i.e., in order to distinguish between the free thiol, the disulfide dimer and mixed disulfide adducts, was not pursued for routine analysis. The individual forms were quantified collectively as dalcetrapib-thiol (dal-thiol) after reduction under basic conditions with dithiothreitol to break disulfide bonds and derivatization with N-ethylmaleimide to stabilize the free thiol. The S-methyl and S-glucuronide metabolites were determined simultaneously with dal-thiol with no effect from the derivatization procedure. Column-switching liquid chromatography-tandem mass spectrometry provided a simple, fast and robust method for analysis of human and animal plasma and human urine samples. Addition of the surfactant Tween 80 to urine prevented adsorptive compound loss. The lower limits of quantitation (LLOQ) were 5 ng/mL for dal-thiol, and 5 ng/mL for the S-methyl and 50 ng/mL for the S-glucuronide metabolites. Using stable isotope-labeled internal standards, inter- and intra-assay precisions were each <15% (<20% at LLOQ) and accuracy was between 85 and 115%. Recovery was close to 100%, and no significant matrix effect was observed. PMID:22541249

  5. Simultaneous determination of drugs of abuse and their main metabolites using pressurized liquid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Arbeláez, Paula; Borrull, Francesc; Maria Marcé, Rosa; Pocurull, Eva

    2014-07-01

    An analytical method based on pressurized liquid extraction (PLE) and liquid chromatography-(electrospray)-tandem mass spectrometry was developed for the simultaneous determination of nicotine, four drugs of abuse (opiates and alkaloids) and four of their main metabolites in sewage sludge. The optimum PLE conditions were: cell volume 11 mL, dichloromethane as extraction solvent, 5 min preheating time, 100 °C temperature, 1500 psi pressure, 60% flush volume, 1 cycle, 15 min static extraction time, 120 s purge time and sample weight 1g. Absolute recoveries for all compounds were between 25% and 65%. Data acquisition was done by selective reaction monitoring and the two most abundant product ions were used for confirmation. Limits of detection were lower than 10 μg/kg dry weight (d.w.) and limits of quantification were between 2.5 and 25 μg/kg (d.w.). The highest concentrations found in sludge samples from two sewage treatment plants were for nicotine and cocaine in the range of 23-173 μg/kg (d.w.) and 9-232 μg/kg (d.w.) respectively. PMID:24840416

  6. Evaluation of transfer rates of multiple pesticides from green tea into infusion using water as pressurized liquid extraction solvent and ultra-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Chen, Hongping; Pan, Meiling; Liu, Xin; Lu, Chengyin

    2017-02-01

    Pesticide residues could be transferred from tea into its infusion and by-products, and subsequently consumed by humans. Extra extraction conditions may induce more pesticide leaching into the infusion and by-products of tea and cause greater damage to humans. The aim of this study is to evaluate the infusion of multiple pesticides from green tea into hot water via pressurized liquid extraction. The results showed that pesticides in spiked samples generally have higher leaching (0.8-45.0%) than those in the positive samples. There was a marked rise of transfer rates when water solubility increased from 20mgL(-1) to 450mgL(-1) and LogKow decreased from 6 to 4. All pesticides had more leaching into hot water using pressurized liquid extraction than traditional tea brewing. This study helps in risk assessment of pesticide residues and in the formulation of maximum residue levels (MRLs) in tea and its by-products. PMID:27596385

  7. Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with the pressurized liquid extraction for the quantification and confirmation of sulfonamides in the foods of animal origin.

    PubMed

    Yu, Huan; Tao, Yanfei; Chen, Dongmei; Wang, Yulian; Huang, Lingli; Peng, Dapeng; Dai, Menghong; Liu, Zhenli; Wang, Xu; Yuan, Zonghui

    2011-09-01

    The residues of sulfonamides (SAs) in the foods of animal origin are of the major concern because they are harmful to the consumer's health and could induce pathogens to develop resistance. Rapid and efficient determination methods are urgently in need. A quantitative high performance liquid chromatography method (HPLC) and a confirmative liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 18 sulfonamides such as sulfamidinum, sulfanilamide, sulfisomidine, sulfadiazine, sulfapyridine, sulfathiazole, sulfamerazine, sulfadimidine, sulfamethoxypyridazine, sulfamethoxydiazine, sulfisoxazole, sulfachloropyridazine, sulfamethoxazole, sulfamonomethoxine, sulfadoxine, sulfaclozine, sulfadimethoxine, sulfaquinoxaline in the muscles, livers and kidneys of swine, bovine and chicken were developed and validated. The sample preparation procedures included a pressurized liquid extraction (PLE) with acetonitrile conducted at elevated temperature (70°C) and pressure (1400 psi). After clean-up with hydrophilic-lipophilic balance cartridge, the extraction solution was concentrated and analyzed by HPLC and LC-MS/MS analysis. 18 SAs were separated by the HPLC with a Zorbax SB-Aq-C18 column and the mobile phase of methanol/acetonitrile/1% acetic acid with a gradient system. The wavelength of UV for the HPLC detection was set at 285 nm. The LC-MS/MS analysis was achieved with a Hypersil Golden column and the mobile phase of acetonitrile and 0.1% formic acid aqueous solution with two gradient systems. The Limits of detection (LOD) and the limits of quantitation (LOQ) were 3 μg/kg and 10 μg/kg, respectively, for both of the HPLC and LC-MS/MS. Linearity was obtained with an average coefficient of determination (R) higher than 0.9980 over a dynamic range from the LOQ value up to 5000 μg/kg. The recoveries of the methods range from 71.1% to 118.3% with the relative standard derivation less than 13%. The peaks of interest with no interferences

  8. Fast, rugged and sensitive ultra high pressure liquid chromatography tandem mass spectrometry method for analysis of cyanotoxins in raw water and drinking water--First findings of anatoxins, cylindrospermopsins and microcystin variants in Swedish source waters and infiltration ponds.

    PubMed

    Pekar, Heidi; Westerberg, Erik; Bruno, Oscar; Lääne, Ants; Persson, Kenneth M; Sundström, L Fredrik; Thim, Anna-Maria

    2016-01-15

    Freshwater blooms of cyanobacteria (blue-green algae) in source waters are generally composed of several different strains with the capability to produce a variety of toxins. The major exposure routes for humans are direct contact with recreational waters and ingestion of drinking water not efficiently treated. The ultra high pressure liquid chromatography tandem mass spectrometry based analytical method presented here allows simultaneous analysis of 22 cyanotoxins from different toxin groups, including anatoxins, cylindrospermopsins, nodularin and microcystins in raw water and drinking water. The use of reference standards enables correct identification of toxins as well as precision of the quantification and due to matrix effects, recovery correction is required. The multi-toxin group method presented here, does not compromise sensitivity, despite the large number of analytes. The limit of quantification was set to 0.1 μg/L for 75% of the cyanotoxins in drinking water and 0.5 μg/L for all cyanotoxins in raw water, which is compliant with the WHO guidance value for microcystin-LR. The matrix effects experienced during analysis were reasonable for most analytes, considering the large volume injected into the mass spectrometer. The time of analysis, including lysing of cell bound toxins, is less than three hours. Furthermore, the method was tested in Swedish source waters and infiltration ponds resulting in evidence of presence of anatoxin, homo-anatoxin, cylindrospermopsin and several variants of microcystins for the first time in Sweden, proving its usefulness. PMID:26755412

  9. MEASUREMENT OF OXIDATIVE STRESS PARAMETERS USING LIQUID CHROMATOGRAPHY - TANDEM MASS SPECTROSCOPY (LC-MS/MS)

    EPA Science Inventory

    What is the study?
    An invited review article. Measurement of oxidative stress parameters using liquid chromatography-tandem mass spectroscopy (LC-MS/MS)
    Why was it done?
    Although oxidative stress is frequently cited as a cause of various adverse biological eff...

  10. Acute neurotoxicity associated with recreational use of methylmethaqualone confirmed by liquid chromatography tandem mass spectrometry.

    PubMed

    Ceschi, A; Giardelli, G; Müller, D M; Elavumkudy, S; Manini, A F; Rauber-Lüthy, C; Hofer, K E

    2013-01-01

    Methylmethaqualone is a sedative designer drug created by adding a methyl group to the 3-phenyl ring of methaqualone, and is at present not subject to restrictive regulation in many countries. To our knowledge, no case of methylmethaqualone abuse has been published to date in the scientific literature, and the only sources of information are users' reports on Web discussion forums and data from preclinical animal studies. We report a case of oral methylmethaqualone abuse confirmed by liquid chromatography tandem mass spectrometry in a 24-year-old previously healthy Caucasian male. Observed symptoms and signs such as central nervous system depression alternating with excitation, psychomotor agitation, muscle hyperactivity, and tachycardia were compatible with methaqualone-induced adverse effects. Except for the mild tachycardia (115 beats/min), other vital signs were normal: blood pressure 134/89 mmHg, body temperature 36.2°C (97.16°F), and peripheral oxygen saturation 99% while breathing room air. The ECG showed no prolongation of the QT interval and the QRS duration was normal. Laboratory analysis revealed a slight increase in creatine kinase (368 U/L) and alanine aminotransferase (90 U/L) serum concentrations. Blood alcohol concentration was 0.32 g/L. Methylmethaqualone was identified in a serum sample collected on admission which was analyzed by a liquid chromatography tandem mass spectrometry toxicological screening method using turbulent flow online extraction. After a few days the patient ingested the same amount of substance with identical symptoms. Based on the chemical structure and animal data, and according to this case report and users' Web reports, methylmethaqualone appears to have a similar acute toxicity profile to methaqualone, with marked psychomotor stimulation. Symptoms of acute toxicity can be expected to resolve with supportive care. PMID:23298217

  11. Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Willison, Stuart A

    2012-12-28

    Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatography–tandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and compared with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) results. An evaluation of both techniques suggests UPLC–MS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 47–99% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA). PMID:23218189

  12. Comparison of several extraction techniques for multiclass analysis of veterinary drugs in eggs using ultra-high pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Garrido Frenich, Antonia; Aguilera-Luiz, María del Mar; Martínez Vidal, Jose Luis; Romero-González, Roberto

    2010-02-28

    This study compared four extraction methods for the simultaneous determination of tetracyclines, macrolides, quinolones, sulphonamides and anthelmintics (including benzimidazoles and avermectins) in eggs by ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solvent extraction, solid-phase extraction (SPE), matrix solid-phase dispersion (MSPD) and modified QuEChERS procedure were compared in terms of recovery and number of veterinary drugs extracted. The solvent extraction procedure with a clean-up step provided better results than the other tested procedures. The QuEChERS procedure was simpler and faster, but extracted fewer compounds than solvent extraction. MSPD did not extract tetracyclines and quinolones, whereas macrolides and tetracyclines were not extracted when SPE was applied. The solvent extraction procedure was validated, obtaining recoveries ranging from 60% (sulfaquinoxaline) to 119% (levamisole) with repeatability values (expressed as relative standard deviations, RSDs) lower than 20% at two concentration levels (10 and 100 microg kg(-1)), except for erythromycin, emamectin and ivermectin that showed RSD values close to 25% at 10 microg kg(-1). Limits of quantification (LOQs) were always equal or lower than 5 microg kg(-1). Finally the method was applied to egg samples, and erythromycin, enrofloxacin, difloxacin, thiabendazole, emamectin and fenbendazole were detected in four samples. PMID:20113729

  13. In-cell clean-up pressurized liquid extraction and gas chromatography-tandem mass spectrometry determination of hydrophobic persistent and emerging organic pollutants in coastal sediments.

    PubMed

    Pintado-Herrera, Marina G; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2016-01-15

    The main goal of this work was to develop, optimize and validate a multi-residue method for the simultaneous determination of 97 contaminants, including fragrances, UV filters, repellents, endocrine disruptors, biocides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organophosphorus flame retardants, and several types of pesticides in marine sediment samples. Extraction and cleanup were integrated into the same step using pressurized liquid extraction (PLE) with in-cell clean-up (1g of alumina). The extraction was performed using dichloromethane at 100 °C, 1500 psi and 3 extraction cycles (5 min per cycle). Extracts were derivatized with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) to improve the signal and sensitivity of some target compounds (i.e., triclosan, 2-hydroxybenzophenone). Separation, identification and quantification of analytes were carried out by gas chromatography (GC) coupled to tandem mass spectrometry. Under optimal conditions, the optimized protocol showed good recovery percentages (70-100%), linearity (>0.99) and limits of detection below 1 ng g(-1) for all compounds. Finally, the method was applied to the analysis of sediment samples from different coastal areas from Andalusia (Spain), where occurrence and distribution of emerging contaminants in sediments is very scarce. Twenty five compounds out of 98 were detected in all samples, with the endocrine disruptor nonylphenol and the fragrance galaxolide showing the highest concentrations, up to 377.6 ng g(-1) and 237.4 ng g(-1), respectively. PMID:26747688

  14. Use of ammonium formate in QuEChERS for high-throughput analysis of pesticides in food by fast, low-pressure gas chromatography and liquid chromatography tandem mass spectrometry.

    PubMed

    González-Curbelo, Miguel Ángel; Lehotay, Steven J; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel

    2014-09-01

    The "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to sample preparation is widely applied in pesticide residue analysis, but the use of magnesium sulfate and other nonvolatile compounds for salting out in the method is not ideal for mass spectrometry. In this study, we developed and evaluated three new different versions of the QuEChERS method using more volatile salts (ammonium chloride and ammonium formate and acetate buffers) to induce phase separation and extraction of 43 representative pesticide analytes of different classes. Fast low-pressure gas chromatography tandem mass spectrometry (LPGC-MS/MS) and liquid chromatography (LC)-MS/MS were used for analysis. The QuEChERS AOAC Official Method 2007.01 was also tested for comparison purposes. Of the studied methods, formate buffering using 7.5g of ammonium formate and 15mL of 5% (v/v) formic acid in acetonitrile for the extraction of 15g of sample (5g for wheat grain) provided the best performance and practical considerations. Method validation was carried out with and without the use of dispersive solid-phase extraction for cleanup, and no significant differences were observed for the majority of pesticides. The method was demonstrated in quantitative analysis for GC- and LC-amenable pesticides in 4 representative food matrices (apple, lemon, lettuce, and wheat grain). With the typical exceptions of certain pH-dependent and labile pesticides, 90-110% recoveries and <10% RSD were obtained. Detection limits were mostly <5ng/g, which met the general need to determine pesticide concentrations as low as 10ng/g for monitoring purposes in food applications. PMID:25047819

  15. Rapid and automated analysis of aflatoxin M1 in milk and dairy products by online solid phase extraction coupled to ultra-high-pressure-liquid-chromatography tandem mass spectrometry.

    PubMed

    Campone, Luca; Piccinelli, Anna Lisa; Celano, Rita; Pagano, Imma; Russo, Mariateresa; Rastrelli, Luca

    2016-01-01

    This study reports a fast and automated analytical procedure for the analysis of aflatoxin M1 (AFM1) in milk and dairy products. The method is based on the simultaneous protein precipitation and AFM1 extraction, by salt-induced liquid-liquid extraction (SI-LLE), followed by an online solid-phase extraction (online SPE) coupled to ultra-high-pressure-liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis to the automatic pre-concentration, clean up and sensitive and selective determination of AFM1. The main parameters affecting the extraction efficiency and accuracy of the analytical method were studied in detail. In the optimal conditions, acetonitrile and NaCl were used as extraction/denaturant solvent and salting-out agent in SI-LLE, respectively. After centrifugation, the organic phase (acetonitrile) was diluted with water (1:9 v/v) and purified (1mL) by online C18 cartridge coupled with an UHPLC column. Finally, selected reaction monitoring (SRM) acquisition mode was applied to the detection of AFM1. Validation studies were carried out on different dairy products (whole and skimmed cow milk, yogurt, goat milk, and powder infant formula), providing method quantification limits about 25 times lower than AFM1 maximum levels permitted by EU regulation 1881/2006 in milk and dairy products for direct human consumption. Recoveries (86-102%) and repeatability (RSD<3, n=6) meet the performance criteria required by EU regulation N. 401/2006 for the determination of the levels of mycotoxins in foodstuffs. Moreover, no matrix effects were observed in the different milk and dairy products studied. The proposed method improves the performance of AFM1 analysis in milk samples as AFM1 determination is performed with a degree of accuracy higher than the conventional methods. Other advantages are the reduction of sample preparation procedure, time and cost of the analysis, enabling high sample throughput that meet the current concerns of food safety and the public

  16. Extraction of 3,4,4'-Trichlorocarbanilide from Rat Fecal Samples for Determination by High Pressure Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Kennedy, Rebekah C; Fling, Russell R; Terry, Paul D; Menn, Fu-Min; Chen, Jiangang; Borman, Christopher J

    2015-07-01

    Triclocarban (3,4,4'-Trichlorocarbanilide; TCC) in the environment has been well documented. Methods have been developed to monitor TCC levels from various matrices including water, sediment, biosolids, plants, blood and urine; however, no method has been developed to document the concentration of TCC in fecal content after oral exposure in animal studies. In the present study, we developed and validated a method that uses liquid extraction coupled with HPLC-MS/MS determination to measure TCC in feces. The limit of detection and limit of quantitation in control rats without TCC exposure was 69.0 ng/g and 92.9 ng/g of feces, respectively. The base levels of TCC in feces were lower than LOD. At 12 days of treatment, the fecal TCC concentration increased to 2220 µg/g among 0.2% w/w exposed animals. The concentration in fecal samples decreased over the washout period in 0.2% w/w treated animals to 0.399 µ/g feces after exposure was removed for 28 days. This method required a small amount of sample (0.1 g) with simple sample preparation. Given its sensitivity and efficiency, this method may be useful for monitoring TCC exposure in toxicological studies of animals. PMID:26184276

  17. Analysis of acrylamide in coffee and cocoa by isotope dilution liquid chromatography-tandem mass spectrometry.

    PubMed

    Aguas, Patricia C; Fitzhenry, Matthew J; Giannikopoulos, Georgina; Varelis, Peter

    2006-08-01

    An accurate and precise method for the quantification of acrylamide using stable isotope dilution liquid chromatography-tandem mass spectrometry was developed and used to measure acrylamide in coffee and cocoa samples. The sample preparation involved extraction of the analyte and its internal standard, 13C3-acrylamide, into water and subsequent defatting of the aqueous extract with dichloromethane. An aliquot of the resulting aqueous extract was then azeotropically dried under reduced pressure and subsequently purified using an aminopropyl-bonded silica cartridge. The purified extracts were then chromatographed on a 5-microm 2.1 x 150 mm Hypercarb column, the effluent of which was monitored for the analyte and its internal standard using positive-ion APCI-selected reaction monitoring. The intra-laboratory reproducibility of the method, expressed as a relative coefficient of variation (%, n=5), was determined at four levels of concentration (12.3, 42.3, 139.3 and 464.8 microg kg(-1)) and was found to vary between 0.6-2.5%. The accuracy of the method was assessed using a reference sample of coffee. The average result obtained using our method differed from the assigned value of the reference material by less than 1%. An analysis of a cocoa sample revealed that the method is capable of precisely estimating acrylamide in challenging matrices down to a level of at least 12.3 microg kg(-1). PMID:16819634

  18. Simultaneous ultra-high-pressure liquid chromatography-tandem mass spectrometry determination of amphetamine and amphetamine-like stimulants, cocaine and its metabolites, and a cannabis metabolite in surface water and urban wastewater.

    PubMed

    Bijlsma, Lubertus; Sancho, Juan V; Pitarch, Elena; Ibáñez, Maria; Hernández, Félix

    2009-04-10

    An ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the simultaneous quantification and confirmation of 11 basic/acidic illicit drugs and relevant metabolites in surface and urban wastewater at ng/L levels. The sample pre-treatment consisted of a solid-phase extraction using Oasis MCX cartridges. Analyte deuterated compounds were used as surrogate internal standards (except for norbenzoylecgonine and norcocaine) to compensate for possible errors resulting from matrix effects and those associated to the sample preparation procedure. After SPE enrichment, the selected drugs were separated within 6min under UHPLC optimized conditions. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyzer (TQD from Waters) in positive-ion mode (ESI+) was used. The excellent selectivity and sensitivity of the TQD analyzer in selected reaction monitoring mode allowed quantification and reliable identification at the LOQ levels. Satisfactory recoveries (70-120%) and precision (RSD<20%) were obtained for most compounds in different types of water samples, spiked at two concentration levels [limit of quantification (LOQ) and 10LOQ]. Thus, surface water was spiked at 30 ng/L and 300 ng/L (amphetamine and amphetamine-like stimulants), 10 ng/L and 100 ng/L (cocaine and its metabolites), 300 ng/L and 3000 ng/L (tetrahydrocannabinol-COOH). Recovery experiments in effluent and influent wastewater were performed at spiking levels of three and fifteen times higher than the levels spiked in surface water, respectively. The validated method was applied to urban wastewater samples (influent and effluent). The acquisition of three selected reaction monitoring transitions per analyte allowed positive findings to be confirmed by accomplishment of ion ratios between the quantification transition and two additional specific confirmation transitions. In general, drug consumption increased in the weekends and

  19. Determination of parabens in serum by liquid chromatography-tandem mass spectrometry: Correlation with lipstick use.

    PubMed

    Tahan, Gabriella Padovani; Santos, Nayara de Kássia Souza; Albuquerque, Ana Carolina; Martins, Isarita

    2016-08-01

    Parabens are the most widely used preservative and are considered to be relatively safe compounds. However, studies have demonstrated that they may have estrogenic activity, and there is ongoing debate regarding the safety and potential cancer risk of using products containing these compounds. In the present work, liquid chromatography-tandem mass spectrometry was applied to determine methylparaben and propylparaben concentrations in serum, and the results were correlated with lipstick application. Samples were analyzed using liquid-liquid extraction, followed by liquid chromatography-tandem mass spectrometry. The validation results demonstrated the linearity of the method over a range of 1-20 ng/mL, in addition to the method's precision and accuracy. A statistically significant difference was demonstrated between serum parabens in women who used lipstick containing these substances compared with those not using this cosmetic (p = 0.0005 and 0.0016, respectively), and a strong association was observed between serum parabens and lipstick use (Spearman correlation = 0.7202). PMID:27154569

  20. Quantification of six cannabinoids and metabolites in oral fluid by liquid chromatography-tandem mass spectrometry.

    PubMed

    Desrosiers, Nathalie A; Scheidweiler, Karl B; Huestis, Marilyn A

    2015-08-01

    Δ(9) -Tetrahydrocannabinol (THC) is the most commonly analyzed cannabinoid in oral fluid (OF); however, its metabolite 11-nor-9-carboxy-THC (THCCOOH) offers the advantage of documenting active consumption, as it is not detected in cannabis smoke. Analytical challenges such as low (ng/L) THCCOOH OF concentrations hampered routine OF THCCOOH monitoring. Presence of minor cannabinoids like cannabidiol and cannabinol offer the advantage of identifying recent cannabis intake. Published OF cannabinoids methods have limitations, including few analytes and lengthy derivatization. We developed and validated a sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for THC, its metabolites, 11-hydroxy-THC and THCCOOH quantification, and other natural cannabinoids including tetrahydrocannabivarin (THCV), cannabidiol (CBD), and cannabigerol (CBG) in 1 mL OF collected with the Quantisal device. After solid-phase extraction, chromatography was performed on a Selectra PFPP column with a 0.15% formic acid in water and acetonitrile gradient with a 0.5 mL/min flow rate. All analytes were monitored in positive mode atmospheric pressure chemical ionization (APCI) with multiple reaction monitoring. Limits of quantification were 15 ng/L THCCOOH and 0.2 µg/L for all other analytes. Linear ranges extended to 3750 ng/L THCCOOH, 100 µg/L THC, and 50 µg/L for all other analytes. Inter-day analytical recoveries (bias) and imprecision at low, mid, and high quality control (QC) concentrations were 88.7-107.3% and 2.3-6.7%, respectively (n = 20). Mean extraction efficiencies and matrix effects evaluated at low and high QC were 75.9-86.1% and 8.4-99.4%, respectively. This method will be highly useful for workplace, criminal justice, drug treatment and driving under the influence of cannabis OF testing. PMID:25428610

  1. Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage.

    PubMed

    Michelotto, André Luiz da Costa; Gasparetto, João Cleverson; Campos, Francinete Ramos; Sydney, Gilson Blitzkow; Pontarolo, Roberto

    2015-01-01

    The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1), with gutta-percha + Sealapex (G2), and with gutta-percha + AH Plus (G3). Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0), applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively), whereas G1 showed significantly higher values (mean: 105.2 ng mL-1). At 60 days, leakage values were 182.6 ng mL-1 for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification. PMID:26313349

  2. Determination of bromate in drinking water by ultraperformance liquid chromatography-tandem mass spectrometry.

    PubMed

    Alsohaimi, Ibrahim Hotan; Alothman, Zeid Abdullah; Khan, Mohammad Rizwan; Abdalla, Mohammad Abulhassan; Busquets, Rosa; Alomary, Ahmad Khodran

    2012-10-01

    Bromate is a byproduct formed as a result of disinfection of bromide-containing source water with ozone or hypochlorite. The International Agency for Research on Cancer has recognized bromate as a possible human carcinogen, thus it is essential to determine in drinking water. Present work highlights a development of sensitive and fast analytical method for bromate determination in drinking water by using ultraperformance liquid chromatography-tandem mass spectrometry. The quality parameters of the developed method were established, obtaining very low limit of detection (0.01 ng/mL), repeatability and reproducibility have been found to be less than 3% in terms of relative standard deviation when analyzing a bromate standard at 0.05 μg/mL with 0.4 min analysis time. Developed method was applied for the analysis of metropolitan and bottled water from Saudi Arabia; 22 samples have been analyzed. Bromate was detected in the metropolitan water samples (from desalinization source) at concentrations ranging between 3.43 and 75.04 ng/mL and in the bottled water samples at concentrations ranging between 2.07 and 21.90 ng/mL. Moreover, in comparison to established analytical methods such as liquid chromatography-tandem mass spectrometry, the proposed method was found to be very sensitive, selective and rapid for the routine analysis of bromate at low level in drinking water. PMID:22815069

  3. Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

    NASA Astrophysics Data System (ADS)

    Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

    2009-04-01

    This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

  4. An Undergraduate Experiment for the Measurement of Perfluorinated Surfactants in Fish Liver by Liquid Chromatography-Tandem Mass Spectrometry

    ERIC Educational Resources Information Center

    Stock, Naomi L.; Martin, Jonathan W.; Ye, Yun; Mabury, Scott A.

    2007-01-01

    A laboratory experiment that provides students a hands-on introduction to the specific techniques of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and electrospray ionization is presented. The students can thus practice the analytical principles of sample extraction, detection, quantification, and quality control using a fresh fish…

  5. Determination of amphetamine and methamphetamine in umbilical cord using liquid chromatography-tandem mass spectrometry

    PubMed Central

    Jones, Joseph; Rios, Rosemarie; Jones, Mary; Lewis, Douglas; Plate, Charles

    2009-01-01

    The use of meconium as a drug-screening matrix for newborns has been the gold standard of care for the past two decades. A recent study using matched pairs of meconium and umbilical cord demonstrated a high degree of agreement. The use of liquid chromatography-tandem mass spectrometry as a means to confirm amphetamines presumptive positive umbilical cord specimens for amphetamine and methamphetamine is described here for the first time. The limit of detection for both compounds was 0.2 ng/g. The limit of quantitation for both compounds was 0.6 ng/g. The assay was linear for both compounds up to 100 ng/g. PMID:19783234

  6. Determination of amphetamine and methamphetamine in umbilical cord using liquid chromatography-tandem mass spectrometry.

    PubMed

    Jones, Joseph; Rios, Rosemarie; Jones, Mary; Lewis, Douglas; Plate, Charles

    2009-11-01

    The use of meconium as a drug-screening matrix for newborns has been the gold standard of care for the past two decades. A recent study using matched pairs of meconium and umbilical cord demonstrated a high degree of agreement. The use of liquid chromatography-tandem mass spectrometry as a means to confirm amphetamines presumptive positive umbilical cord specimens for amphetamine and methamphetamine is described here for the first time. The limit of detection for both compounds was 0.2 ng/g. The limit of quantitation for both compounds was 0.6 ng/g. The assay was linear for both compounds up to 100 ng/g. PMID:19783234

  7. Determination of albendazole sulfoxide in human plasma by using liquid chromatography-tandem mass spectrometry.

    PubMed

    Saraner, Nihal; Özkan, Güler Yağmur; Güney, Berrak; Alkan, Erkin; Burul-Bozkurt, Nihan; Sağlam, Onursal; Fikirdeşici, Ezgi; Yıldırım, Mevlüt

    2016-06-01

    A rapid, simple and sensitive method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of albendazole sulfoxide (ABZOX) in human plasma. The plasma samples were extracted by protein precipitation using albendazole sulfoxide-d3 as internal standard (IS). The chromatographic separation was performed on Waters Xbridge C18Column (100×4.6mm, 3.5μm) with a mobile phase consisting of ammonia solution, water and methanol at a flow rate of 0.70mL/min. ABZOX was detected and identified by mass spectrometry with electrospray ionization (ESI) in positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 3-1500ng/mL for ABZOX. This method was successfully applied to the bioequivalence study in human plasma samples. PMID:27060508

  8. Determination of ethylglucuronide in oral fluid by ultra-performance liquid chromatography- tandem mass spectrometry.

    PubMed

    Hegstad, S; Johnsen, L; Mørland, J; Christophersen, A S

    2009-05-01

    An ultra-performance liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of ethylglucuronide (EtG) in oral fluid. Sample clean-up was achieved by solid-phase extraction with a Hyper-SEP SAX column. Negative ionization was performed in the multiple reaction monitoring mode. Two transitions were monitored for the analyte and one for the internal standard EtG-d(5). The calibration range was 4.4-222 ng/mL. The recovery of the analyte ranged from 86 to 99%, and the between-assay precisions ranged from 5 to 9% RSD. The limit of quantification was found to be 4.4 ng/mL. The concentration of EtG in oral fluid collected 2-14 h after a moderate alcohol intake varied from 13.3 to 57.7 ng/mL. PMID:19470222

  9. Direct Measurement of Free Estradiol in Human Serum and Plasma by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Ray, Julie A; Kushnir, Mark M; Rockwood, Alan L; Meikle, A Wayne

    2016-01-01

    We describe a direct method of measurement of free estradiol using equilibrium dialysis followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Serum aliquots and internal standards are extracted by liquid-liquid extraction using methyl-tert-butyl ether (MTBE) followed by derivatization with dansyl chloride. An API 5500 mass spectrometer operated in positive electrospray mode is used for detection. PMID:26602122

  10. Confirmatory analysis of acetylgestagens in plasma using liquid chromatography-tandem mass spectrometry.

    PubMed

    Mortensen, Sarah Kelly; Pedersen, Mikael

    2007-03-14

    A confirmatory method has been developed and validated for the determination of chlormadinone acetate (CMA), megestrol acetate (MGA), melengestrol acetate (MLA) and medroxyprogesterone acetate (MPA) in bovine and porcine plasma. Analytes are extracted from plasma samples using matrix-assisted liquid-liquid extraction (LLE) on Extrelut NT columns followed by C18 solid-phase extraction (SPE). Analytes were analysed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and quantification was performed using matrix-matched calibration standards in combination with deuterated internal standards. In accordance with Commission Decision 2002/657/EC, two ion transitions were monitored for each analyte. Decision limits (CCalpha) were estimated by analysing 20 blank plasma samples and ranged from 0.1 to 0.2 ng mL(-1). Detection capabilities (CCbeta) were estimated using 20 plasma samples fortified at 0.5 ng mL(-1) and were <0.5 ng mL(-1). In the range 0.5-2 ng mL(-1), the mean intra-laboratory reproducibility of the analytes ranged from 6 to 18% (%R.S.D.). Analytes were shown to be stable in fortified plasma samples for >8 months when stored at -20 degrees C. PMID:17386714

  11. [Microchip-based reversed-phase liquid chromatography-tandem mass spectrometry platform for protein analysis].

    PubMed

    Liang, Yu; Wu, Ci; Dai, Zhongpeng; Liang, Zuocheng; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-06-01

    Due to the high throughput and high sensitivity, the hyphenation of microchip-based high performance liquid chromatography with tandem mass spectrometry has been paid much attention. In our recent work, with poly (lauryl methacrylate-co-trimethylolpropane trimethacrylate) monolithic materials prepared in microchannels as trap and separation columns, conventional micro-liquid chromatography pumps and valves for fluidic control, and a small-bore open-tube capillary attached to the outlet channel as chip-mass spectrometer (MS) interface, the microchip-based reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) platform was established, and applied for the identification of proteins. By such platform, 100 ng digest of bovine serum albumin (BSA) was successfully analyzed with the sequence coverages as 39.37%, 37.89% and 34.10% (with the relative standard deviation (RSD) of 7.3%) in three runs, separately. To evaluate the chip-to-chip reproducibility, BSA was identified by such platform with the microchips from different batches containing trap column, separation column and chip-MS interface. The obtained sequence coverage and the number of peptides identified were comparable. All these results showed high sensitivity and good reproducibility of such platform, demonstrating the great potential for rapid protein analysis. PMID:22032155

  12. Confirmation and quantification of clenbuterol in horse urine using liquid chromatography tandem mass spectrometry triple quadrupole.

    PubMed

    Bishop, Jennifer; Heffron, Brendan; Taddei, Lisa; Benoit, Marc; Hurt, Laura; Costello, Sara; Gross, Melissa; Negrusz, Adam

    2015-03-01

    Clenbuterol (CLE) is used in horses as a bronchodilator and for its anabolic steroid-like effects. CLE is a Class 3 drug according to current Association of Racing Commissioners International (ARCI) Uniform Classification Guidelines. The Racing Medication and Testing Consortium recommended a urine CLE threshold of 140 pg/mL after careful scientific review of the results of studies describing the disposition of CLE in the horse and this threshold was adopted by the ARCI. Enzyme-linked immunosorbent assay was previously used to screen samples for CLE in Illinois, but could not detect such low concentrations in urine. Thus, a liquid-liquid extraction of CLE from urine followed by quantification by liquid chromatography-tandem mass spectrometry was developed and validated. Method validation included testing stability, ion suppression and enhancement, precision, accuracy and uncertainty. Intra-, interday and total precision and accuracy were calculated for each control and found to be within the ±15% acceptance range. The Guide to the Expression of Uncertainty in Measurement approach was used to calculate uncertainty, which was 11% at the 95% confidence level. In the past 5 years, only 15 samples were reported as positive for CLE in Illinois. This new method was used in a pilot program to screen and confirm samples received from thoroughbred and harness horses. PMID:25505053

  13. Determination of ecliptasaponin A in rat plasma and tissues by liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhao, Jing; Liu, Erwei; Han, Lifeng; Wang, Linlin; Zhang, Yi; Wang, Tao; Fang, Shiming; Gao, Xiumei

    2016-06-01

    A sensitive, rapid and specific high-performance liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) was developed to determine ecliptasaponin A in rat plasma and tissues after oral administration. Ginsenoside Rg1 was used as the internal standard (IS). The plasma and tissues samples were prepared by liquid-liquid extraction with ethyl acetate and separated on an Eclipse Plus C18 column (2.1 mm × 150 mm, 5 µm) at a flow rate of 0.4 mL/min using acetonitrile and water (containing 0.05% acetic acid) as the mobile phase. The tandem mass detection was carried out with eletrospray ionization in negative mode. Quantification was performed by using multiple reaction monitoring (MRM), which monitored the fragmentation of m/z 633.4→587.2 for ecliptasaponin A and m/z 859.4→637.4 for the IS. The calibration curves obtained were linear in different matrices, and the lower limit of quantification (LLOQ) achieved was 0.5 ng/mL both for rat plasma and tissues. The intra- and inter-day precisions were below 15%. This method was successfully applied to pharmacokinetic study of ecliptasaponin A in rat plasma and tissues after oral administration. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26378987

  14. Determination of ethyl glucuronide in human hair by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    Yaldiz, Fadile; Daglioglu, Nebile; Hilal, Ahmet; Keten, Alper; Gülmen, Mete Korkut

    2013-10-01

    Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been utilized as a marker for alcohol intake. This study presents development, validation and application of a new hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the analysis of EtG in human hair samples. The linearity was assessed in the range of 5-2000 pg/mg hair, with a correlation coefficient of >0.99. The method was selective and sensitive, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.05 pg/mg and 0.18 pg/mg in hair, respectively. Differently from the extraction procedures in the literature, a fast and simple liquid-liquid method was used and highest recoveries and cleanest extracts were obtained. The method was successfully applied to 30 human hair samples which were taken from those who state they consume alcohol. EtG concentrations in the hair samples of alcohol users participated in this study, ranged between 1.34 and 82.73 pg/mg. From the concentration of EtG in hair strands 20 of the 30 subjects can be considered regular moderate drinkers. PMID:24112322

  15. Drug screening of whole blood by ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Oiestad, Elisabeth Leere; Johansen, Unni; Oiestad, Ase Marit Leere; Christophersen, Asbjørg Solberg

    2011-06-01

    An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for screening of drugs in whole blood has been developed and validated. Samples were prepared by supported liquid-liquid extraction on ChemElute(®) columns with ethyl acetate/heptane (4:1). LC separation was achieved with an Acquity HSS T3-column (2.1 100 mm, 1.8-μm particle). Mass detection was performed by positive ion mode electrospray MS-MS and included the following drugs/metabolites: morphine, codeine, ethyl morphine, oxycodone, buprenorphine, methadone, cocaine, methylphenidate, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), Δ(9)-tetrahydrocannabinol (THC), fentanyl, alprazolam, bromazepam, clonazepam, diazepam, nordiazepam, 3-OH-diazepam, fenazepam, flunitrazepam, lorazepam, nitrazepam, oxazepam, zopiclone, zolpidem, carisoprodol, and meprobamate. The cycle time was 9 min, and within- and between-day relative coefficients of variation varied from 1% to 33% and 2% to 58%, respectively. Extraction recoveries from whole blood were > 50% except for morphine and THC. The limit of quantitation was 0.1 to 521 ng/mL, depending on the drug. PMID:21619723

  16. Comprehensive characterization of anticoagulant rodenticides in sludge by liquid chromatography-tandem mass spectrometry.

    PubMed

    Gómez-Canela, Cristian; Lacorte, Silvia

    2016-08-01

    The occurrence of 10 commonly used anticoagulant rodenticides in centrifuged sludge of 27 wastewater treatment plants was evaluated using solid-liquid extraction (SLE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Activated carbon, alumina, and Florisil cartridges with methanol/dichloromethane as eluting solvents were tested in combination with primary-secondary amine (PSA) to optimize an efficient sample cleanup. PSA in combination with Florisil was the best methodology to extract anticoagulant rodenticides in sludge providing recoveries between 42 ± 0.5 and 100 ± 2 %. Warfarin, bromadiolone, ferulenol, and coumachlor were the most ubiquitous compounds in sludge at concentrations up to 84.2 ng g(-1) for the latter. Coumatetralyl, dicoumarol, and brodifacoum were detected sporadically at levels between 6.1 and 17.4 ng g(-1). On the contrary, acenocoumarol, difenacoum, and flocoumafen were not detected in any sample. Finally, we estimated the amount of anticoagulant rodenticides discharged via sludge in order to determine the potential impact to agricultural soil according to different sludge usage practices in the region investigated. This study demonstrates that anticoagulant rodenticides are accumulated in sludge during activated sludge treatment and that the application of sludge as fertilizers may pose a future environmental risk, if not controlled. PMID:27146526

  17. Ethyl glucuronide determination in meconium and hair by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    Tarcomnicu, Isabela; van Nuijs, Alexander L N; Aerts, Katrien; De Doncker, Mireille; Covaci, Adrian; Neels, Hugo

    2010-03-20

    Ethyl glucuronide (EtG) detection in non-conventional matrices, such as hair and meconium, can provide useful information on alcohol abuse over a long time frame, for example during pregnancy or after a withdrawal treatment. This study reports on the development, validation and application of a new hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the analysis of EtG in meconium and hair. For each matrix, the sample preparation and the chromatographic separation were thoroughly optimised. Additionally, experiments with reversed-phase liquid chromatography were also performed in the development stages. Analyses were carried out using a Phenomenex Luna HILIC column (150 mm x 3 mm, 5 microm) and a mobile phase composed by ammonium acetate 2mM and acetonitrile, in gradient. Different SPE cartridges (Oasis MAX, Oasis WAX, aminopropyl silica) and solvents were tested in order to obtain the highest recoveries and cleanest extracts. Optimal results were obtained for meconium with aminopropyl cartridges, while for hair an incubation of 16 h with 2 mL of water and acetonitrile (50/50, v/v) provided good results. The analytical method was validated for both matrices (meconium and hair) by assessing linearity, precision, accuracy, recovery and limit of quantification. The calibration curve concentrations ranged from 50 to 1200 pg/mg for meconium and from 20 to 1000 pg/mg for hair. Real meconium and hair samples were analyzed and results were consistent with literature. PMID:20061101

  18. Analysis of aristolochic acids, aristololactams and their analogues using liquid chromatography tandem mass spectrometry.

    PubMed

    Yu, Jie; Ma, Chao-Mei; Wang, Xuan; Shang, Ming-Ying; Hattori, Masao; Xu, Feng; Jing, Yu; Dong, Shi-Wen; Xu, Yu-Qiong; Zhang, Cui-Ying; Cai, Shao-Qing

    2016-08-01

    More than 80 aristolochic acids (AAs) and aristololactams (ALs) have been found in plants of the Aristolochiaceae family, but relatively few have been fully studied. The present study aimed at developing and validating a liquid chromatography tandem mass spectrometry (LC/MS(n)) for the analysis of these compounds. We characterized the fragmentation behaviors of 31 AAs, ALs, and their analogues via high performance liquid chromatography coupled with electrospray ionization mass spectrometry. We summarized their fragmentation rules and used these rules to identify the constituents contained in Aristolochia contorta, Ar. debilis, Ar. manshurensis, Ar. fangchi, Ar. cinnabarina, and Ar. mollissima. The AAs and ALs showed very different MS behaviors. In MS(1) of AAs, the characteristic pseudomolecular ions were [M + NH4](+), [M + H](+), and [M + H - H2O](+). However, only [M + H](+) was found in the MS(1) of ALs, which was simpler than that of AAs. Distinct MS(n)fragmentation patterns were found for AAs and ALs, showing the same skeleton among the different substituent groups. The distribution of the 31 constituents in the 6 species of Aristolochia genus was reported for the first time. 25 Analogues of AAs and ALs were detected in this genus. A hierarchical schemes and a calculating formula of the molecular formula of these nitrophenanthrene carboxylic acids and their lactams were proposed. In conclusion, this method could be applied to identification of similar unknown constituents in other plants. PMID:27608953

  19. A novel method for analysing key corticosteroids in polar bear (Ursus maritimus) hair using liquid chromatography tandem mass spectrometry.

    PubMed

    Weisser, Johan J; Hansen, Martin; Björklund, Erland; Sonne, Christian; Dietz, Rune; Styrishave, Bjarne

    2016-04-01

    This paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. Such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. We developed a combined pressurized liquid extraction (PLE)-solid phase extraction (SPE) procedure for corticosteroid extraction and clean-up followed by high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. This procedure allows for the simultaneous determination of multiple steroids, which is in contrast to previous polar bear studies based on ELISA techniques. Absolute method recoveries were 81%, 75% and 60% for cortisol, corticosterone and aldosterone, respectively. We applied the developed method on a hair sample pooled from four East Greenland polar bears. Herein cortisol and corticosterone were successfully determined in levels of 0.32±0.02ng/g hair and 0.13±0.02ng/g hair, respectively. Aldosterone was below limit of detection (LOD<0.17ng/g). The cortisol hair concentration found in these East Greenland polar bears was consistent with cortisol levels previously determined in the Southern Hudson Bay and James Bay in Canada using ELISA kits. PMID:26945133

  20. Ultra-preconcentration and determination of selected pharmaceutical and personal care products in different water matrices by solid-phase extraction combined with dispersive liquid-liquid microextraction prior to ultra high pressure liquid chromatography tandem mass spectrometry analysis.

    PubMed

    Celano, Rita; Piccinelli, Anna Lisa; Campone, Luca; Rastrelli, Luca

    2014-08-15

    Pharmaceutical and personal care products (PPCPs) are one of the most important classes of emerging contaminants. The potential of ecological and environmental impacts associated with PPCPs are of particular concern because they continually penetrate the aquatic environment. This work describes a novel ultra-preconcentration technique for the rapid and highly sensitive analysis of selected PPCPs in environmental water matrices at ppt levels. Selected PPCPs were rapidly extracted and concentrated from large volumes of aqueous solutions (500 and 250mL) by solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and then analyzed using UHPLC-MS/MS. Experimental parameters were carefully investigated and optimized to achieve the best SPE-DLLME efficiency and higher enrichment factors. The best results were obtained using the ternary mixture acetonitrile/methanol/dichloromethane 3:3:4, v/v/v, both as SPE eluent and DLLME extractant/dispersive mixture. DLLME aqueous solution (5% NaCl, 10mgL(-1) TBAB) was also modified to improve the extraction efficiency of more hydrophilic PPCPs. Under the optimal conditions, an exhaustive extraction for most of the investigated analytes (recoveries >70%), with a precision (RSD <10%) and very high enrichment factors were attained for different aqueous matrices (drinking, sea, river and wastewater). Method detection and quantification limits were at very low ppt levels and below 1 and 3ngL(-1), respectively, for 15 of selected PPCPs. The proposed analytical procedure offers numerous advantages such as the simplicity of operation, rapidity, a high enrichment factor and sensitivity. So it is suitable for monitoring and studies of occurrence of PPCPs in different environmental compartments. PMID:24939087

  1. Optimized liquid chromatography tandem mass spectrometry approach for the determination of diquat and paraquat herbicides.

    PubMed

    Hao, Chunyan; Zhao, Xiaoming; Morse, David; Yang, Paul; Taguchi, Vince; Morra, Franca

    2013-08-23

    Liquid chromatography tandem mass spectrometry (LC-MS/MS) determination of quaternary ammonium herbicides diquat (DQ) and paraquat (PQ) can be very challenging due to their complicated chromatographic and mass spectrometric behaviors. Various multiple reaction monitoring (MRM) transitions from radical cations M(+) and singly charged cations [M-H](+), have been reported for LC-MS/MS quantitation under different chromatographic and mass spectrometric conditions. However, interference peaks were observed for certain previously reported MRM transitions in our study. Using a Dionex Acclaim(®) reversed-phase and HILIC mixed-mode LC column, we evaluated the most sensitive MRM transitions from three types of quasi-molecular ions of DQ and PQ, elucidated the cross-interference phenomena, and demonstrated that the rarely mentioned MRM transitions from dications M(2+) offered the best selectivity for LC-MS/MS analysis. Experimental parameters, such as IonSpray (IS) voltage, source temperature, declustering potential (DP), column oven temperature, collision energy (CE), acid and salt concentrations in the mobile phases were also optimized and an uncommon electrospray ionization (ESI) capillary voltage of 1000V achieved the highest sensitivity. Employing the proposed dication transitions 92/84.5 for DQ and 93/171 for PQ, the direct aqueous injection LC-MS/MS method developed was able to provide a method detection limit (MDL) of 0.1μg/L for the determination of these two herbicides in drinking water. PMID:23871562

  2. Determination of ten sulphonamides in egg by liquid chromatography-tandem mass spectrometry.

    PubMed

    Forti, A F; Scortichini, G

    2009-04-01

    A precise and reliable method for the determination of 10 sulphonamide antibiotics (sulfadiazine, sulfathiazole, sulfamerazine, sulfamethazine, sulfamethoxypyridazine, sulfachloropyridazine, sulfamethoxazole, sulfamonomethoxine, sulfadimethoxine and sulfaquinoxaline) in egg by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed. Drugs were extracted using a mixture of dichloromethane/acetone (50:50, v/v), acidified with acetic acid and then cleaned-up on a cation-exchange solid-phase extraction (SPE) cartridge. The chromatographic separation was performed by gradient on a C(18) column with a mobile phase of methanol-water containing 0.1% formic acid and 5mM ammonium acetate, then sulphonamides were detected in a triple-quadrupole mass spectrometer operated in positive electrospray ionization mode (ESI(+)). The method was validated at 15, 30 and 45 microgkg(-1). These levels were much lower than the corresponding maximum residue limit of 100 microgkg(-1) set for sulphonamides in several matrices but not in eggs, where the presence of such residues is not permitted. Results were quantitated against the selected internal standard (13)C(6)-sulphamethazine and also according to the matrix-matched approach. The within-laboratory reproducibility, expressed as a relative standard deviation, never exceeded 21%. All decision limit (CCalpha) values lied in the range between 16.1 and 20.5 microgkg(-1) and the corresponding results for detection capability (CCbeta) were 16.9 and 25.7 microgkg(-1). Ruggedness was estimated according to the Youden robustness test. PMID:19286032

  3. Determination of melatonin in Acyrthosiphon pisum aphids by liquid chromatography-tandem mass spectrometry.

    PubMed

    Escrivá, Laura; Manyes, Lara; Barberà, Miquel; Martínez-Torres, David; Meca, Guiseppe

    2016-03-01

    Melatonin is a hormone mainly involved in the regulation of circadian and seasonal rhythms in both invertebrates and vertebrates. Despite the identification of melatonin in many insects, its involvement in the insect seasonal response remains unclear. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for melatonin analysis in aphids (Acyrthosiphon pisum) for the first time. After comparing two different procedures and five extraction solvents, a sample preparation procedure with a mixture of methanol/water (50:50) was selected for melatonin extraction. The method was validated by analyzing melatonin recovery at three spiked concentrations (5, 50 and 100 pg/mg) and showed satisfactory recoveries (75-110%), and good repeatability, expressed as relative standard deviation (<10%). Limits of detection (LOD) and quantitation (LOQ) were 1 pg/mg and 5 pg/mg, respectively. Eight concentration levels were used for constructing the calibration curves which showed good linearity between LOQ and 200 times LOQ. The validated method was successfully applied to 26 aphid samples demonstrating its usefulness for melatonin determination in insects. This is -to our knowledge- the first identification of melatonin in aphids by LC-MS/MS. PMID:26778054

  4. Creatinine measurements in 24 h urine by liquid chromatography--tandem Mass Spectrometry.

    PubMed

    Park, Eun-Kee; Watanabe, Takaho; Gee, Shirley J; Schenker, Marc B; Hammock, Bruce D

    2008-01-23

    A simple, sensitive, and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining urinary creatinine was developed and used to evaluate 24 h urine samples collected during an exposure study. Urine (1 microL) was diluted with methanol and then directly applied to LC-MS/MS. Under electrospray ionization (ESI) conditions, the transition molecules of creatinine and creatinine- d3 were observed at m/ z 114 > 44 and m/ z 117 > 47, respectively. The retention time of creatinine was 0.59 min. The linear range was 1-2000 ng/mL, with a detection limit in urine of 1 ng/mL. LC-MS/MS and colorimetric end-point methods were significantly associated ( R2 = 0.8785, p < 0.0001). The LC-MS/MS method to determine creatinine in 24 h urine samples had shorter retention times, was more sensitive, reliable, reproducible, simple, selective, and used a smaller sample size than other LC-MS/MS or commercial methods. PMID:18092755

  5. Quantitative determination of methylnaltrexone in human serum using liquid chromatography-tandem mass spectrometry.

    PubMed

    Oswald, Stefan; Schumacher, Gitta; Siegmund, Werner

    2011-12-15

    Methylnaltrexone (MNTX) is a novel peripherally acting μ-opioid antagonist that prevents peripheral side effects of opioid drugs such as constipation without affecting the analgesia. We developed a selective and sensitive assay to measure MTNX concentrations in human serum. The drug was measured after protein precipitation with perchloric acid using naltrexone as internal standard and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for detection. The chromatography was performed isocratically on a RP18 column using 25 mM ammonium acetate buffer (pH 4)/acetonitrile (90%/10%; flow rate 200 μl/min) as mobile phase. The MS/MS analysis was performed in positive ionization mode monitoring the m/z transitions 356.4/284.2 for MNTX and 342.4/324.2 for naltrexone. The method was validated according to selectivity, linearity, accuracy, precision, recovery, matrix effects and stability. The validation range for MNTX in serum was 0.5-250 ng/ml. The developed LC-MS/MS was shown to be valid and successfully applied to measure serum-concentration-time curves of MNTX in a pilot study in healthy volunteers. PMID:21880450

  6. Antibiotic toxicity and absorption in zebrafish using liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Fan; Qin, Wei; Zhang, Jing-Pu; Hu, Chang-Qin

    2015-01-01

    Evaluation of drug toxicity is necessary for drug safety, but in vivo drug absorption is varied; therefore, a rapid, sensitive and reliable method for measuring drugs is needed. Zebrafish are acceptable drug toxicity screening models; we used these animals with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in a multiple reaction monitoring mode to quantify drug uptake in zebrafish to better estimate drug toxicity. Analytes were recovered from zebrafish homogenate by collecting supernatant. Measurements were confirmed for drugs in the range of 10-1,000 ng/mL. Four antibiotics with different polarities were tested to explore any correlation of drug polarity, absorption, and toxicity. Zebrafish at 3 days post-fertilization (dpf) absorbed more drug than those at 6 h post-fertilization (hpf), and different developmental periods appeared to be differentially sensitive to the same compound. By observing abnormal embryos and LD50 values, zebrafish embryos at 6 hpf were considered to be suitable for evaluating embryotoxicity. Also, larvae at 3 dpf were adapted to measure acute drug toxicity in adult mammals. Thus, we can exploit zebrafish to study drug toxicity and can reliably quantify drug uptake with LC-MS/MS. This approach will be helpful for future studies of toxicology in zebrafish. PMID:25938774

  7. [Determination of pesticides in Chinese dumplings using liquid chromatography-tandem mass spectrometry].

    PubMed

    Okamoto, You; Takatori, Satoshi; Kitagawa, Yoko; Okihashi, Masahiro; Fukui, Naoki; Murata, Hiroshi; Sumimoto, Tatsuo; Tanaka, Yukio; Obana, Hirotaka

    2009-02-01

    A rapid and easy multiresidue method for determination of pesticide residues in Chinese dumplings using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed. Pesticide residues were extracted with ethyl acetate in the presence of anhydrous magnesium sulfate in a disposable tube using a homogenizer. The extract was concentrated and reconstituted in hexane, followed by acetonitrile-hexane partition to remove lipids. The acetonitrile layer was purified with a double-layered cartridge column (graphite carbon black/primary secondary amine silica gel). After removal of the solvent, the extract was resolved in methanol/water and analyzed with LC-MS/MS. Recovery tests of 99 pesticide residues from Chinese dumpling were performed at 20 and 100 ng/g, and 72 pesticides exhibited acceptable recoveries (70-120%) with low relative standard deviations (<20%) at both concentrations. The time for sample preparation with 12 samples to test solutions was approximately 6 hr. This method could be useful for determination of pesticide residues in the Chinese dumplings. PMID:19325220

  8. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li

    2014-06-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil. PMID:25269254

  9. Quantitative determination of ondansetron in human plasma by enantioselective liquid chromatography-tandem mass spectrometry.

    PubMed

    Liu, Ke; Dai, Xiaojian; Zhong, Dafang; Chen, Xiaoyan

    2008-03-15

    A sensitive and enantioselective method was developed and validated for the determination of ondansetron enantiomers in human plasma using enantioselective liquid chromatography-tandem mass spectrometry. The enantiomers of ondansetron were extracted from plasma using ethyl acetate under alkaline conditions. HPLC separation was performed on an ovomucoid column using an isocratic mobile phase of methanol-5 mM ammonium acetate-acetic acid (20:80:0.02, v/v/v) at a flow rate of 0.40 mL/min. Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode, using the transitions of m/z 294-->170 for ondansetron enantiomers, and m/z 285-->124 for tropisetron (internal standard). The method was linear in the concentration range of 0.10-40 ng/mL for each enantiomer using 200 microL of plasma. The lower limit of quantification (LLOQ) for each enantiomer was 0.10 ng/mL. The intra- and inter-assay precision was 3.7-11.6% and 5.6-12.3% for R-(-)-ondansetron and S-(+)-ondansetron, respectively. The accuracy was 100.4-107.1% for R-(-)-ondansetron and 103.3-104.9% for S-(+)-ondansetron. No chiral inversion was observed during the plasma storage, preparation and analysis. The method was successfully applied to characterize the pharmacokinetic profiles of ondansetron enantiomers in healthy volunteers after an intravenous infusion of 8 mg racemic ondansetron. PMID:18299256

  10. Quantitative analysis of phenibut in rat brain tissue extracts by liquid chromatography-tandem mass spectrometry.

    PubMed

    Grinberga, Solveiga; Zvejniece, Liga; Liepinsh, Edgars; Dambrova, Maija; Pugovics, Osvalds

    2008-12-01

    Phenibut (3-phenyl-4-aminobutyric acid) is a gamma-aminobutyric acid mimetic drug, which is used clinically as a mood elevator and tranquilizer. In the present work, a rapid, selective and sensitive liquid chromatography-tandem mass spectrometry method for quantification of phenibut in biological matrices has been developed. The method is based on protein precipitation with acidic acetonitrile followed by isocratic chromatographic separation using acetonitrile-formic acid (0.1% in water; 8:92, v/v) mobile phase on a reversed-phase column. Detection of the analyte was performed by electrospray ionization mass spectrometry in multiple reaction monitoring mode with the precursor-to-product ion transition m/z 180.3 --> m/z 117.2. The calibration curve was linear over the concentration range 50-2000 ng/mL. The lower limit of quantification for phenibut in rat brain extracts was 50 ng/mL. Acceptable precision and accuracy were obtained over the whole concentration range. The validated method was successfully applied in a pharmacological study to analyze phenibut concentration in rat brain tissue extract samples. PMID:19034959

  11. Aflatoxin M1 determination in cheese by liquid chromatography-tandem mass spectrometry.

    PubMed

    Cavaliere, Chiara; Foglia, Patrizia; Guarino, Chiara; Marzioni, Francesca; Nazzari, Manuela; Samperi, Roberto; Laganà, Aldo

    2006-12-01

    A new method for determining aflatoxin M1 (AFM1) in cheese by liquid chromatography-tandem mass spectrometry has been developed. Two methodologies were compared for sample extraction. The first one involves sample extraction with dichloromethane for hard, aged cheese or acetone for fresh cheese and includes a preliminary matrix solid-phase dispersion-extraction step before solid-phase extraction (SPE) clean-up by a Carbograph-4 cartridge. The second method uses a water/methanol solution (90:10, v/v) extraction at 150 degrees C before clean-up. The average recoveries of AFM1 from samples spiked at levels of 0.25-0.45 microg/kg, were 81-92% and the precision (RSD) ranged from 3 to 7% with the first method, whilst the average recoveries were 79-84%, and RSD ranged from 7 to 15% for the second method. Due to different matrix effect, the quantification limits were 0.019-0.025 microg/kg in the first case and 0.048-0.143 microg/kg in the second one, depending on cheese typology. PMID:17056052

  12. Fate and occurrence of alkylphenolic compounds in sewage sludges determined by liquid chromatography tandem mass spectrometry.

    PubMed

    Koh, Y K K; Chiu, T Y; Paterakis, N; Boobis, A; Scrimshawe, M D; Lester, J N; Cartmell, E

    2009-12-01

    An analytical method has been developed and applied to determine the concentrations of the nonionic alkylphenol polyethoxylate surfactants and their metabolites, alkylphenoxy carboxylates and alkyphenols, in sewage sludges. The compounds were extracted with methanol/acetone (1:1 v/v) from sludge, and concentrated extracts were cleaned by silica solid-phase extraction prior to determination by liquid chromatography tandem mass spectrometry. The recoveries, determined by spiking sewage sludge at two concentrations, ranged from 51% to 89% with method detection limits from 6 microg kg(-1) to 60 microg kg(-1). The methodology was subsequently applied to sludge samples obtained from a carbonaceous activated sludge plant, a nitrifying/denitrifying activated sludge plant and a nitrifying/ denitrifying activated sludge plant with phosphorus removal. Concentrations of nonylphenolic compounds were two to three times higher than their octyl analogues. Long-chain nonylphenol polyethoxylates (NP3-12EO) ranged from 16 microg kg(-1) to 11754 microg kg(-1). The estrogenic metabolite nonylphenol was present at concentrations ranging from 33 microg kg(-1) to 6696 microg kg(-1). PMID:20088206

  13. Determination of 3-mercaptopyruvate in rabbit plasma by high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Stutelberg, Michael W; Vinnakota, Chakravarthy V; Mitchell, Brendan L; Monteil, Alexandre R; Patterson, Steven E; Logue, Brian A

    2014-02-15

    Accidental or intentional cyanide poisoning is a serious health risk. The current suite of FDA approved antidotes, including hydroxocobalamin, sodium nitrite, and sodium thiosulfate is effective, but each antidote has specific major limitations, such as large effective dosage or delayed onset of action. Therefore, next generation cyanide antidotes are being investigated to mitigate these limitations. One such antidote, 3-mercaptopyruvate (3-MP), detoxifies cyanide by acting as a sulfur donor to convert cyanide into thiocyanate, a relatively nontoxic cyanide metabolite. An analytical method capable of detecting 3-MP in biological fluids is essential for the development of 3-MP as a potential antidote. Therefore, a high performance liquid chromatography tandem mass spectrometry (HPLC-MS-MS) method was established to analyze 3-MP from rabbit plasma. Sample preparation consisted of spiking the plasma with an internal standard ((13)C3-3-MP), precipitation of plasma proteins, and reaction with monobromobimane to inhibit the characteristic dimerization of 3-MP. The method produced a limit of detection of 0.1μM, a linear dynamic range of 0.5-100μM, along with excellent linearity (R(2)≥0.999), accuracy (±9% of the nominal concentration) and precision (<7% relative standard deviation). The optimized HPLC-MS-MS method was capable of detecting 3-MP in rabbits that were administered sulfanegen, a prodrug of 3-MP, following cyanide exposure. Considering the excellent performance of this method, it will be utilized for further investigations of this promising cyanide antidote. PMID:24480329

  14. Development of a high-performance liquid chromatography - Tandem mass spectrometry urinary pterinomics workflow.

    PubMed

    Burton, Casey; Shi, Honglan; Ma, Yinfa

    2016-07-13

    Pteridines have evoked considerable interest from the scientific community owing to their prominent roles in human health and disease. The availability of analytical methodologies suitable for comprehensive pteridine profiling, termed here as "pterinomics", has been limited by inconsistent sample preparation and the exclusion of lesser studied pteridine derivatives. In response, the present study describes a new pterinomics workflow using a high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) methodology for the simultaneous analysis of 15 pteridine derivatives including four structural isomers, marking the largest quantitative pteridine panel that has been studied to-date. The validated method possessed excellent sensitivity with method detection limits (0.025 μg L(-1) to 0.5 μg L(-1)) that were comparable or superior to existing techniques. Spiked recovery studies demonstrated the technique was both accurate (88-112%) and precise (RSD: 0-6%). A comparative study of commonly used oxidative pretreatments, including triiodide, permanganate, and manganese dioxide, revealed that the oxidative mechanisms were inefficient, complex, and concentration dependent. Finally, 50 clinical urine specimens were examined with the new technique wherein 10 pteridine derivatives were quantified and population ranges have been given. This technique can be used to examine pteridine molecular epidemiology and biochemistry to support related research applications, and may further be readily extended to include additional pteridine derivatives and biological matrices for specific applications. PMID:27237839

  15. Analysis of nerve agent metabolites from nail clippings by liquid chromatography tandem mass spectrometry.

    PubMed

    Appel, Amanda S; Logue, Brian A

    2016-09-15

    While several methods for the bioanalysis of nerve agents or their metabolites have been developed for the verification of nerve agent exposure, these methods are generally limited in the amount of time after an exposure that markers of exposure can be detected (due to rapid metabolism from biological matrices). In this study, a method for the analysis of nerve agent hydrolysis products from nail clippings was developed to allow evaluation of nails as a long-term repository of these markers. Pinacolyl methylphosphonic acid (PMPA) and isopropyl methylphosphonic acid (IMPA) were extracted from nail samples with N,N-dimethylformamide and subsequently analyzed by liquid chromatography-tandem mass spectrometry. Limits of detection for PMPA and IMPA were 0.3μg/kg and 7.5μg/kg and linear ranges were 0.75-300μg/kg and 30-1500μg/kg, respectively. Precision was within 10% and 8% for PMPA and IMPA, respectively, and accuracy was 100±12% for both analytes. The approach presented here is complementary to current methods for nerve agent exposure verification, and should allow for long-term determination of nerve agent poisoning. PMID:27474780

  16. Quantification of X. laevis vitellogenin by liquid chromatography tandem mass spectrometry.

    PubMed

    Luna, Leah G; Coady, Katherine

    2016-02-01

    Over the last several decades, there has been an increase in public awareness and regulatory activity in regard to the presence of emerging contaminants in the environment that may have the potential to interact with the endocrine system of exposed wildlife. Alterations in vitellogenin (VTG), a high density yolk precursor protein, can indicate endocrine activity in oviparous species, including many fish and amphibians. While various methodologies and experiments have been performed to characterize baseline VTG concentrations among commonly studied fish species, fewer methodologies for accurately quantifying amphibian VTG are available. Since there is relatively little information available on background VTG levels in male and female frogs, the present investigation set out to quantify baseline levels of VTG in juvenile as well as adult male and female African clawed frogs (Xenopus laevis) using a newly developed liquid chromatography tandem mass spectrometry method. This new methodology for quantifying VTG in X. laevis frog blood plasma can be applied in mechanistic and toxicity studies with X. laevis to better characterize potential endocrine modes of action. PMID:26562177

  17. Enrichment of Integral Membrane Proteins for Proteomic Analysis Using Liquid Chromatography-Tandem Mass Spectrometry

    SciTech Connect

    Blonder, Josip; Goshe, Michael B.; Moore, Ronald J.; Pasa-Tolic, Liljiana; Masselon, Christophe D.; Lipton, Mary S.; Smith, Richard D.

    2002-04-01

    Currently, most proteomic studies rely on liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect and identify constituent peptides of enzymatically digested proteins obtained from various organisms and cell types. However, sample preparation methods for isolating membrane proteins typically involve the use of detergents, chaotropes, or reducing reagents that often interfere with electrospray ionization (ESI). To increase the identification of integral membrane proteins by LC-ESI-MS/MS, a sample preparation method combining carbonate extraction and surfactant-free organics solvent-assisted solubilization and proteolysis was developed and used to target the membrane subproteome of Deinococcus radiodurans. Out of 503 proteins identified, 135 were recognized as hydrophobic based on their positive grand average of hydropathicity values that covers 15% of the theoretical hydrophobic proteome. Using the PSORT algorithm, 268 identified proteins were recognized as integral membrane proteins covering 21% and 43% of the predicted integral cytoplasmic and outer membrane proteins, respectively. Of the integral cytoplasmic membrane proteins containing four or more predicted transmembrane domains (TMDs), 65% were identified by detecting at least one peptide spanning a TMD using LC-MS/MS. The extensive identification of highly hydrophobic proteins containing multiple TMDs confirms the efficacy of the described sample preparation protocol to isolate and solubilize integral membrane proteins and validates the method for large-scale analysis of bacterial membrane subproteomes using LC-ESI-MS/MS.

  18. Antibiotic Toxicity and Absorption in Zebrafish Using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Zhang, Fan; Qin, Wei; Zhang, Jing-Pu; Hu, Chang-Qin

    2015-01-01

    Evaluation of drug toxicity is necessary for drug safety, but in vivo drug absorption is varied; therefore, a rapid, sensitive and reliable method for measuring drugs is needed. Zebrafish are acceptable drug toxicity screening models; we used these animals with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in a multiple reaction monitoring mode to quantify drug uptake in zebrafish to better estimate drug toxicity. Analytes were recovered from zebrafish homogenate by collecting supernatant. Measurements were confirmed for drugs in the range of 10–1,000 ng/mL. Four antibiotics with different polarities were tested to explore any correlation of drug polarity, absorption, and toxicity. Zebrafish at 3 days post-fertilization (dpf) absorbed more drug than those at 6 h post-fertilization (hpf), and different developmental periods appeared to be differentially sensitive to the same compound. By observing abnormal embryos and LD50 values, zebrafish embryos at 6 hpf were considered to be suitable for evaluating embryotoxicity. Also, larvae at 3 dpf were adapted to measure acute drug toxicity in adult mammals. Thus, we can exploit zebrafish to study drug toxicity and can reliably quantify drug uptake with LC-MS/MS. This approach will be helpful for future studies of toxicology in zebrafish. PMID:25938774

  19. Investigation of the biotransformation of osthole by liquid chromatography/tandem mass spectrometry.

    PubMed

    Li, Jie; Chan, Wan

    2013-02-23

    Osthole is an active ingredient and one of the major coumarin compounds that were identified in the genus Cnidium moonnieri (L.) Cussion, the fruit of which was used as traditional Chinese medicine to treat male impotence, ringworm infection and blood stasis conventionally. Recent studies revealed that osthole has diverse pharmacological effects, such as improving male sexual dysfunction, anti-diabetes, and anti-hypertentions. The inhibition of thrombosis and platelet aggregation and protection of central nerve were also observed. On the other hand, the metabolism of osthole has not yet been investigated thoroughly. Herein the biotransformation of osthole in rat was investigated after oral administration of osthole by using efficient and sensitive ultra-performance liquid chromatography-tandem quadrupole-time of flight mass spectrometry (UPLC-QTOF/MS). Eighteen osthole metabolites and the parent drug were detected and identified in rat urine. Fourteen metabolites of osthole were identified and characterized for the first time. Structures of metabolites of osthole were elucidated by comparing fragment pattern under MS/MS scan and change of molecular weight with those of osthole. The main phase I metabolic pathways were summed as 7-demethylation, 8-dehydrogenation, hydroxylation on coumarin and 3,4-epoxide. Sulfate conjugates were detected as phase II metabolites of osthole. PMID:23245246

  20. Endogenous glucocorticoid analysis by liquid chromatography-tandem mass spectrometry in routine clinical laboratories.

    PubMed

    Hawley, James M; Keevil, Brian G

    2016-09-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful analytical technique that offers exceptional selectivity and sensitivity. Used optimally, LC-MS/MS provides accurate and precise results for a wide range of analytes at concentrations that are difficult to quantitate with other methodologies. Its implementation into routine clinical biochemistry laboratories has revolutionised our ability to analyse small molecules such as glucocorticoids. Whereas immunoassays can suffer from matrix effects and cross-reactivity due to interactions with structural analogues, the selectivity offered by LC-MS/MS has largely overcome these limitations. As many clinical guidelines are now beginning to acknowledge the importance of the methodology used to provide results, the advantages associated with LC-MS/MS are gaining wider recognition. With their integral role in both the diagnosis and management of hypo- and hyperadrenal disorders, coupled with their widespread pharmacological use, the accurate measurement of glucocorticoids is fundamental to effective patient care. Here, we provide an up-to-date review of the LC-MS/MS techniques used to successfully measure endogenous glucocorticoids, particular reference is made to serum, urine and salivary cortisol. PMID:27208627

  1. Multiresidue Analysis of Pesticides in Straw Roughage by Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Zhang, Zihao; Feng, Mengyuan; Zhu, Kechen; Han, Lijun; Sapozhnikova, Yelena; Lehotay, Steven J

    2016-08-10

    A multiresidue analytical method using a modification of the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) sample preparation approach combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was established and validated for the rapid determination of 69 pesticides at different levels (1-100 ng/g) in wheat and rice straws. In the quantitative analysis, the recoveries ranged from 70 to 120%, and consistent RSDs ≤ 20% were achieved for most of the target analytes (53 pesticides in wheat straw and 58 in rice straw). Almost all of the analytes achieved good linearity with R(2) > 0.98, and the limit of validation levels (LVLs) for diverse pesticides ranged from 1 to 10 ng/g. Different extraction and cleanup conditions were evaluated in both types of straw, leading to different options. The use of 0.1% formic acid or not in extraction with acetonitrile yielded similar final outcomes, but led to the use of a different sorbent in dispersive solid-phase extraction. Both options are efficient and useful for the multiresidue analysis of targeted pesticides in wheat and rice straw samples. PMID:26881844

  2. Pharmacokinetic study of dendrobine in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Wang, Shuanghu; Wu, Haiya; Geng, Peiwu; Lin, Yingying; Liu, Zezheng; Zhang, Lijing; Ma, Jianshe; Zhou, Yunfang; Wang, Xianqin; Wen, Congcong

    2016-07-01

    Dendrobine, considered as the major active alkaloid compound, has been used for the quality control and discrimination of Dendrobium which is documented in the Chinese Pharmacopoeia. In this work, a sensitive and simple ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for determination of dendrobine in rat plasma is developed. After addition of caulophyline as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 (2.1 ×100 mm, 1.7 µm) column with acetonitrile and 0.1% formic acid as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring mode was used for quantification using target fragment ions m/z 264.2 → 70.0 for dendrobine and m/z 205.1 → 58.0 for IS. Calibration plots were linear throughout the range 2-1000 ng/mL for dendrobine in rat plasma. The RSDs of intra-day and inter-day precision were both <13%. The accuracy of the method was between 95.4 and 103.9%. The method was successfully applied to pharmacokinetic study of dendrobine after intravenous administration. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26525040

  3. Determination of 23 phthalic acid esters in food by liquid chromatography tandem mass spectrometry.

    PubMed

    Xu, Dunming; Deng, Xiaojun; Fang, Enhua; Zheng, Xianghua; Zhou, Yu; Lin, Liyi; Chen, Luping; Wu, Ming; Huang, Zhiqiang

    2014-01-10

    A rapid and sensitive method was developed for the determination of 23 phthalates in food samples including milk-based products, distilled liquor, wine, beverage, grain, meat, oil, biscuit (cookie), and canned food by liquid chromatography tandem mass spectrometry (LC-MS/MS). Liquid samples were exacted by acetonitrile, while solid samples were prepared by QuEChERS or glass-based SPE methods. The 23 phthalates were separated on Poroshell 120 EC-C18 column and followed by positive electrospray ionization as well as multi-reaction monitoring provided by a triple-quadrupole tandem mass spectrometer. To reduce contamination, the plastic materials were avoided in sample handling and preparation . The LODs were between 0.8 and 15 μg kg(-1) and LOQs were between 10 and 100 μg kg(-1). By using different concentrations: 100, 500, and 1000 μg kg(-1)) for DINP and DIDP; 50, 100, and 1000 μg kg(-1) for other 21 phthalate compounds, the spiked recoveries were within 75.5-115.2% and the relative standard deviations (RSDs) were in the range of 3.2-18.9%. The proposed protocol was then applied to the analysis of 623 real samples collected from the two sides of the Taiwan Straits, and the DEHP was found in almost all samples tested in this study, with levels ranging from 0.02 to 2685 mg kg(-1). The present study demonstrated a rapid, sensitive, and accurate method for determining 23 phthalates in foodstuffs. PMID:24326131

  4. Anion exchange SPE and liquid chromatography-tandem mass spectrometry in GHB analysis.

    PubMed

    Elian, Albert A; Hackett, Jeffery

    2011-12-01

    In this study, the extraction of γ-hydroxybutyrate (GHB) from urine using solid-phase extraction (SPE) is described. SPE was performed on anion exchange columns after samples of urine had been diluted with de-ionized water. After application of the diluted samples containing GHB-d(6) as an internal standard, the sorbent was washed with deionized water and methanol and dried. The GHB was eluted from the SPE column with a solvent consisting of methanol containing 6% glacial acetic acid. The eluent was collected, evaporated to dryness, and dissolved in mobile phase (100 μL) for analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative multiple reaction monitoring (MRM) mode. Liquid chromatography was performed in gradient mode employing a biphenyl column and a mobile phase consisting of acetontitrile (containing 0.1% formic acid) and 0.1% aqueous formic acid. The total run time for each analysis was less than 5 min. The limits of detection/quantification for this method were determined to be 50 and 100 ng/mL, respectively. The method was found to be linear from 500 ng/mL to 10,000 ng/mL (r(2)>0.995). The recovery of GHB was found to be greater than 75%. In this report, results of authentic urine samples analyzed for GHB by this method are presented. GHB concentrations in these samples were found to be range from less than 500 ng/mL to 5110 ng/mL. PMID:22055831

  5. Determination of Heterocyclic Amines and Acrylamide in Agricultural Products with Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Lee, Kyung-Jun; Lee, Gae-Ho; Kim, HaeSol; Oh, Min-Seok; Chu, Seok; Hwang, In Ju; Lee, Jee-yeon; Choi, Ari; Kim, Cho-il

    2015-01-01

    Heterocyclic amines (HCAs) and acrylamide are unintended hazardous substances generated by heating or processing of foods and are known as carcinogenic and mutagenic agents by the animal experiments. A simple method was established for a rapid and accurate determination of 12 types of HCAs (IQ, MeIQ, Glu-P-1, Glu-P-2, MeIQx, Trp-P-1, Trp-P-2, PhIP, AαC, MeAαC, Harman and Norharman) and acrylamide in three food matrices (non-fat liquid, non-fat solid and fat solid) by isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). In every sample, a mixture of internal standards including IQ-d3, MeIQx-d3, PhIP-d3, Trp-P-2-13C2-15N and MeAαC-d3 was spiked for quantification of HCAs and 13C3-acrylamide was also spiked for the analysis of acrylamide. HCAs and acrylamide in sample were extracted with acetonitrile and water, respectively, and then two solid-phase extraction cartridges, ChemElut: HLB for HCAs and Accucat: HLB for acrylamide, were used for efficiently removing interferences such as pigment, lipid, polar, nonpolar and ionic compounds. Established method was validated in terms of recovery, accuracy, precision, limit of detection, limit of quantitation, and linearity. This method showed good precision (RSD < 20%), accuracy (71.8~119.1%) and recovery (66.0~118.9%). The detection limits were < 3.1 ng/g for all analytes. The correlation coefficients for all the HCAs and acrylamide were > 0.995, showing excellent linearity. These methods for the detection of HCAs and acrylamide by LC-MS/MS were applied to real samples and were successfully used for quantitative monitoring in the total diet study and this can be applied to risk assessment in various food matrices. PMID:26483884

  6. Determination of neonicotinoid insecticides and strobilurin fungicides in particle phase atmospheric samples by liquid chromatography-tandem mass spectrometry.

    PubMed

    Raina-Fulton, Renata

    2015-06-01

    A liquid chromatography-tandem mass spectrometry method has been developed for the determination of neonicotinoids and strobilurin fungicides in the particle phase fraction of atmosphere samples. Filter samples were extracted with pressurized solvent extraction, followed by a cleanup step with solid phase extraction. Method detection limits for the seven neonicotinoid insecticides and six strobilurin fungicides were in the range of 1.0-4.0 pg/m(3). Samples were collected from June to September 2013 at two locations (Osoyoos and Oliver) in the southern Okanagan Valley Agricultural Region of British Columbia, where these insecticides and fungicides are recommended for use on tree fruit crops (apples, pears, cherries, peaches, apricots) and vineyards. This work represents the first detection of acetamiprid, imidacloprid, clothianidin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin in particle phase atmospheric samples collected in the Okanagan Valley in Canada. The highest particle phase atmospheric concentrations were observed for imidacloprid, pyraclostrobin, and trifloxystrobin at 360.0, 655.6, and 1908.2 pg/m(3), respectively. PMID:25961332

  7. Monolith immuno-affinity enrichment liquid chromatography tandem mass spectrometry for quantitative protein analysis of recombinant bovine somatotropin in serum.

    PubMed

    Smits, Nathalie G E; Blokland, Marco H; Wubs, Klaas L; Nessen, Merel A; van Ginkel, Leen A; Nielen, Michel W F

    2015-08-01

    The use of recombinant bovine somatotropin (rbST) to enhance milk production is approved in several countries, but it is prohibited in the European Union. According to EU legislation, it is necessary to confirm positive screening results prior to enforcement. Although adequate screening assays are available nowadays, development of liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory methods to detect low levels of rbST is still a challenge. Here, we present a novel approach using immuno-affinity enrichment on monolithic micro-columns in combination with state-of-the-art ultra-high pressure LC-MS/MS (UHPLC-MS/MS) detection. The developed approach enables detection and confirmation of rbST in serum at a decision limit (CCα) concentration of 0.8 ng mL(-1). Furthermore, the method is easy to handle, robust and reproducible. We successfully applied the confirmatory method to serum samples from rbST treated cows that were found suspect after immunoassay-based screening. The use of rbST could be confirmed over 1 week after treatment, and the developed method demonstrated the sensitivity needed for effective control. Graphical Abstract Graphical summary of the workflow, for serum preparation, enrichment with monolith microcolumns and LC-MS/MS measurement of rbST. PMID:26077745

  8. A single-step pesticide extraction and clean-up multi-residue analytical method by selective pressurized liquid extraction followed by on-line solid phase extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry for complex matrices.

    PubMed

    Rodrigues, Elsa Teresa; Pardal, Miguel Ângelo; Salgueiro-González, Noelia; Muniategui-Lorenzo, Soledad; Alpendurada, Maria Fátima

    2016-06-24

    Pesticides, a group of compounds linked to human activity, may, when in toxic levels, have a profound effect on water quality, and hence result in adverse consequences to aquatic life and ultimately to human health. Analytical challenges arise when successfully trying to determine these levels in environmental complex matrices. Therefore, fast, simple, sensitive and selective analytical methodologies for multi-residue determination of pesticides (atrazine, azoxystrobin, bentazon, λ-cyhalothrin, penoxsulam and terbuthylazine) in sediment, macrophytes (algae and aquatic plants) and aquatic animals were developed and validated. The established methods were matrix-dependent and were based on Selective Pressurized Liquid Extraction (SPLE) followed by on-line Solid Phase Extraction and Ultra Performance Liquid Chromatography-tandem Mass Spectrometry (on-line SPE-UPLC-ESI-MS/MS). This cutting-edge research methodology uses a small amount of sample, is time saving and reduces the use of organic solvents in compliance with Green Chemistry principles. The analytical features were adequate for all compounds in all studied matrices. The established methodology was applied on real marine samples and no pesticide concentrations above their respective method quantification limits were measured in sediments or aquatic plants. However, terbuthylazine was found in the macroalgae Ulva spp. (108ngg(-1)dw) and all the prospected pesticides were measured above their respective method quantification limits in the bivalve Scrobicularia plana (atrazine: 48ngg(-1)dw, azoxystrobin: 64ngg(-1)dw, bentazon: 33ngg(-1)dw, λ-cyhalothrin: 2531ngg(-1)dw, penoxsulam: 50ngg(-1)dw, and terbuthylazine: 44ngg(-1)dw). PMID:27234845

  9. Quantitative determination of perfluorooctanoic acid in serum and plasma by liquid chromatography tandem mass spectrometry.

    PubMed

    Flaherty, John M; Connolly, Paul D; Decker, Emily R; Kennedy, S Mark; Ellefson, Mark E; Reagen, William K; Szostek, Bogdan

    2005-05-25

    A selective and sensitive method for analysis of perfluorooctanoic acid (PFOA) in human serum and plasma, utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS), has been developed and thoroughly validated to satisfy strict FDA guidelines for bioanalytical methods. A simple, automated sample preparation procedure, involving extraction of the target analyte with acetonitrile on protein precipitation media in a 96-well plate format was developed, allowing efficient handling of large numbers of samples. The proposed method uses the calibration standards prepared in a surrogate matrix (rabbit serum or plasma) and (13)C-labeled PFOA as the internal standard to account for matrix effects, instrument drift, and extraction efficiency. Human serum and plasma could not be used for matrix matching of calibration standards as endogenous levels of PFOA observed in the control human serum and plasma significantly exceeded the targeted lower limit of quantitation (LLOQ) of the method. Precision and accuracy of the method were demonstrated by analysis of rabbit serum and plasma control samples fortified at 0.5, 5, and 40 ng/mL PFOA and human serum and plasma fortified at 1.0, 5.0, 40 ng/mL PFOA. The LLOQ of 0.5 ng/mL PFOA was experimentally demonstrated for rabbit and human serum and plasma. Within-day precision and accuracy, short-term stability, freeze-thaw stability, equivalence of response between PFOA and APFO (the ammonium salt of PFOA), and dilution of concentrated samples were also investigated. The results of the validation experiments comply with the precision and accuracy limits defined by the FDA guidance document: "Guidance for Industry, Bioanalytical Method Validation", May 2001. PMID:15833298

  10. Quantification and pharmacokinetics of crizotinib in rats by liquid chromatography-tandem mass spectrometry.

    PubMed

    Qiu, Feng; Gu, Yanan; Wang, Tingting; Gao, Yingying; Li, Xiao; Gao, Xiangyu; Cheng, Shan

    2016-06-01

    Crizotinib is a small molecule inhibitor of anaplastic lymphoma kinase (ALK) and can be used to treat ALK-positive nonsmall-cell lung cancer. A rapid and simple high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of crizotinib in rat plasma using a chemical synthetic compound buspirone as the internal standard (IS). The plasma samples were pretreated by a simple protein precipitation with methanol-acetonitrile (1:1, v/v). Chromatographic separation was successfully achieved on an Agilent Zorbax XDB C18 column (2.1 × 50 mm, 3.5 µm). The gradient elution system was composed of 0.1% formic acid aqueous solution and 0.1% formic acid in methanol solution. The flow rate was set at 0.50 mL/min. The multiple reaction monitoring was based on the transitions of m/z = 450.3 → 177.1 for crizotinib and 386.2 → 122.2 for buspirone (IS). The assay was successfully validated to demonstrate the selectivity, matrix effect, linearity, lower limit of quantification, accuracy, precision, recovery and stability according to the international guidelines. The lower limit of quantification was 1.00 ng/mL in 50 μL of rat plasma. This LC-MS/MS assay was successfully applied to the quantification and pharmacokinetic study of crizotinib in rats after intravenous and oral administration of crizotinib. The oral absolute bioavailability of crizotinib in rats was 68.6 ± 9.63%. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26467669

  11. Simultaneous quantification of multiple urinary naphthalene metabolites by liquid chromatography tandem mass spectrometry.

    PubMed

    Ayala, Daniel C; Morin, Dexter; Buckpitt, Alan R

    2015-01-01

    Naphthalene is an environmental toxicant to which humans are exposed. Naphthalene causes dose-dependent cytotoxicity to murine airway epithelial cells but a link between exposure and human pulmonary disease has not been established. Naphthalene toxicity in rodents depends on P450 metabolism. Subsequent biotransformation results in urinary elimination of several conjugated metabolites. Glucuronide and sulfate conjugates of naphthols have been used as markers of naphthalene exposure but, as the current studies demonstrate, these assays provide a limited view of the range of metabolites generated from the parent hydrocarbon. Here, we present a liquid chromatography tandem mass spectrometry method for measurement of the glucuronide and sulfate conjugates of 1-naphthol as well as the mercapturic acids and N-acetyl glutathione conjugates from naphthalene epoxide. Standard curves were linear over 2 log orders. On column detection limits varied from 0.91 to 3.4 ng; limits of quantitation from 1.8 to 6.4 ng. The accuracy of measurement of spiked urine standards was -13.1 to + 5.2% of target and intra-day and inter-day variability averaged 7.2 (± 4.5) and 6.8 (± 5.0) %, respectively. Application of the method to urine collected from mice exposed to naphthalene at 15 ppm (4 hrs) showed that glutathione-derived metabolites accounted for 60-70% of the total measured metabolites and sulfate and glucuronide conjugates were eliminated in equal amounts. The method is robust and directly measures several major naphthalene metabolites including those derived from glutathione conjugation of naphthalene epoxide. The assays do not require enzymatic deconjugation, extraction or derivatization thus simplifying sample work up. PMID:25853821

  12. An improved method for measuring metaldehyde in surface water using liquid chromatography tandem mass spectrometry

    PubMed Central

    Schumacher, Melanie; Castle, Glenn; Gravell, Anthony; Mills, Graham A.; Fones, Gary R.

    2016-01-01

    The molluscicide metaldehyde (2,4,6,8-tetramethyl-1,3,5,7-tetraoxocanemetacetaldehyde) is an emerging pollutant. It is frequently detected in surface waters, often above the European Community Drinking Water Directive limit of 0.1 μg/L for a single pesticide. Gas chromatography mass spectrometry (GC–MS) can be used to determine metaldehyde in environmental waters, but this method requires time consuming extraction techniques prior to instrumental analysis. Use of liquid chromatography-tandem mass spectrometry (LC–MS/MS) can overcome this problem. We describe a novel LC–MS/MS method, using a methylamine mobile phase additive, coupled with on-line sample enrichment that allows for the rapid and sensitive measurement of metaldehyde in surface water. Only the methylamine adduct of metaldehyde was formed with other unwanted alkali metal adducts and dimers being suppressed. As considerably less collision energy is required to fragment the methylamine adduct, a five-fold improvement in method sensitivity, compared to a previous method using an ammonium acetate buffer mobile phase was achieved. This new approach offers: • A validated method that meets regulatory requirements for the determination of metaldehyde in surface water. • Improved reliability of quantification over existing LC–MS/MS methods by using stable precursor ions for multiple reaction monitoring. • Low limits of quantification for tap water (4 ng/L) and river water (20 ng/L) using only 800 μL of sample; recoveries > 97%. PMID:27054094

  13. Determination of Bedaquiline in Human Serum Using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Bolhuis, Mathieu; van Hateren, Kai; Sturkenboom, Marieke; Akkerman, Onno; de Lange, Wiel; Greijdanus, Ben; van der Werf, Tjip; Touw, Daan

    2015-01-01

    Bedaquiline, a diarylquinoline for the treatment of multidrug-resistant tuberculosis (TB), relies on exposure-dependent killing. As data on drug exposure in specific populations are scarce, pharmacokinetic studies may be of interest. No simple and robust validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been reported to date. Therefore, a new method using a quadrupole mass spectrometer was developed for analysis of bedaquiline and N-monodesmethyl bedaquiline (M2) in human serum, using deuterated bedaquiline as the internal standard. The calibration curve was linear over a range of 0.05 (lower limit of quantification [LLOQ]) to 6.00 mg/liter for both bedaquiline and M2, with correlation coefficient values of 0.997 and 0.999, respectively. The calculated accuracy ranged from 1.9% to 13.6% for bedaquiline and 2.9% to 8.5% for M2. Within-run precision ranged from 3.0% to 7.2% for bedaquiline and 3.1% to 5.2% for M2, and between-run precision ranged from 0.0% to 4.3% for bedaquiline and 0.0% to 4.6% for M2. Evaluation of serum concentrations in a patient receiving bedaquiline showed high levels at the end of treatment, reflecting accumulation of the drug. More observational pharmacokinetic data are needed to relate altered drug concentrations to clinical outcome or adverse drug effects. A simple LC-MS/MS method to quantify bedaquiline and M2 levels in human serum using a deuterated internal standard has been validated. This method can be used in clinical studies and daily practice. PMID:26149993

  14. Simultaneous quantification of Pacific ciguatoxins in fish blood using liquid chromatography-tandem mass spectrometry.

    PubMed

    Mak, Yim Ling; Wu, Jia Jun; Chan, Wing Hei; Murphy, Margaret B; Lam, James C W; Chan, Leo L; Lam, Paul K S

    2013-04-01

    Ciguatera fish poisoning (CFP) is a food intoxication caused by exposure to ciguatoxins (CTXs) in coral reef fish. Rapid analytical methods have been developed recently to quantify Pacific-CTX-1 (P-CTX-1) in fish muscle, but it is destructive and can cause harm to valuable live coral reef fish. Also fish muscle extract was complex making CTX quantification challenging. Not only P-CTX-1, but also P-CTX-2 and P-CTX-3 could be present in fish, contributing to ciguatoxicity. Therefore, an analytical method for simultaneous quantification of P-CTX-1, P-CTX-2, and P-CTX-3 in whole blood of marketed coral reef fish using sonication, solid-phase extraction (SPE), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. The optimized method gave acceptable recoveries of P-CTXs (74-103 %) in fish blood. Matrix effects (6-26 %) in blood extracts were found to be significantly reduced compared with those in muscle extracts (suppressed by 34-75 % as reported in other studies), thereby minimizing potential for false negative results. The target P-CTXs were detectable in whole blood from four coral reef fish species collected in a CFP-endemic region. Similar trends in total P-CTX levels and patterns of P-CTX composition profiles in blood and muscle of these fish were observed, suggesting a relationship between blood and muscle levels of P-CTXs. This optimized method provides an essential tool for studies of P-CTX pharmacokinetics and pharmacodynamics in fish, which are needed for establishing the use of fish blood as a reliable sample for the assessment and control of CFP. PMID:23392409

  15. An improved method for measuring metaldehyde in surface water using liquid chromatography tandem mass spectrometry.

    PubMed

    Schumacher, Melanie; Castle, Glenn; Gravell, Anthony; Mills, Graham A; Fones, Gary R

    2016-01-01

    The molluscicide metaldehyde (2,4,6,8-tetramethyl-1,3,5,7-tetraoxocanemetacetaldehyde) is an emerging pollutant. It is frequently detected in surface waters, often above the European Community Drinking Water Directive limit of 0.1 μg/L for a single pesticide. Gas chromatography mass spectrometry (GC-MS) can be used to determine metaldehyde in environmental waters, but this method requires time consuming extraction techniques prior to instrumental analysis. Use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) can overcome this problem. We describe a novel LC-MS/MS method, using a methylamine mobile phase additive, coupled with on-line sample enrichment that allows for the rapid and sensitive measurement of metaldehyde in surface water. Only the methylamine adduct of metaldehyde was formed with other unwanted alkali metal adducts and dimers being suppressed. As considerably less collision energy is required to fragment the methylamine adduct, a five-fold improvement in method sensitivity, compared to a previous method using an ammonium acetate buffer mobile phase was achieved. This new approach offers: •A validated method that meets regulatory requirements for the determination of metaldehyde in surface water.•Improved reliability of quantification over existing LC-MS/MS methods by using stable precursor ions for multiple reaction monitoring.•Low limits of quantification for tap water (4 ng/L) and river water (20 ng/L) using only 800 μL of sample; recoveries > 97%. PMID:27054094

  16. Quantitative determination of sarsasapogenin in rat plasma using liquid chromatography-tandem mass spectrometry.

    PubMed

    Yang, Bo; Liu, Zhirui; Hu, Jing; Lai, Xiaodan; Xia, Peiyuan

    2016-06-01

    Sarsasapogenin, a natural compound from Chinese medical herb Anemarrhena asphodeloides Bge., has recently received a great deal of attention due to its various bioactivities. In this study, an easy and applicable liquid chromatography tandem mass spectrometry method for the quantification of sarsasapogenin in rat plasma was developed. Sample preparation was accomplished through a simple one-step protein precipitation procedure with methanol. Negative electrospray ionization was performed using multiple reactions monitoring (MRM) mode with transitions of m/z 417.4/273.2 for sarsasapogenin, and 415.2/271.4 for diosgenin (internal standard). The calibration curve was linear over the range of 0.5-500ng/mL (r=0.9994), with a lower limit of quantification at 0.5ng/mL. The RSD of intra- and inter-day precision was below 6.41%, and accuracy ranged from 87.60% to 99.20%. The RSD of matrix effect and recovery yield was within ±15% of nominal concentrations and sarsasapogenin was stable during stability tests. This validated method had been successfully applied to the preclinical pharmacokinetic studies of sarsasapogenin in rats. The half-life (t1/2) was (15.1±2.3), (16.1±3.0) and (15.4±3.9) h after single intragastric administration of 25, 50 and 100mg/kg sarsasapogenin, respectively. And it was found that, the area under the plasma concentration versus time curve (AUC0-72h) and the maximum plasma concentration (Cmax) were linearly related to dose. PMID:27107248

  17. Determination of Urinary Creatinine in Washington State Residents via Liquid Chromatography/Tandem Mass Spectrometry.

    PubMed

    West, Caroline E; Rhodes, Blaine N

    2014-01-01

    A viable, quick, and reliable method for determining urinary creatinine by liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and used to evaluate spot urine samples collected for the Washington Environmental Biomonitoring Survey (WEBS): part of the Washington State Department of Health, Public Health Laboratories (PHL). 50 µL of urine was mixed with a 1 : 1 acetonitrile/water solution containing deuterated creatinine as the internal standard and then analyzed by LC/MS/MS. Utilizing electrospray ionization (ESI) in positive mode, the transition ions for creatinine and creatinine-d3 were determined to be 114.0 to 44.1 (quantifier), 114.0 to 86.1 (qualifier), and 117.0 to 47.1 (creatinine-d3). The retention time for creatinine was 0.85 minutes. The linear calibration range was 20-4000 mg/L, with a limit of detection at 1.77 mg/L and a limit of quantitation at 5.91 mg/L. LC/MS/MS and the colorimetric Jaffé reaction were associated significantly (Pearson r = 0.9898 and R (2) = 0.9797, ρ ≤ 0.0001). The LC/MS/MS method developed at the PHL to determine creatinine in the spot urine samples had shorter retention times, and was more sensitive, reliable, reproducible, and safer than other LC/MS/MS or commercial methods such as the Jaffé reaction or modified versions thereof. PMID:25614740

  18. Simultaneous determination of eight corticosteroids in bovine tissues using liquid chromatography-tandem mass spectrometry.

    PubMed

    Tölgyesi, Adám; Sharma, Virender K; Fekete, Szabolcs; Lukonics, Dóra; Fekete, Jenő

    2012-10-01

    This paper describes a newly developed method for the simultaneous determination of eight corticosteroid residues in bovine muscle, liver and kidney samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The determination of methylprednisone, the main metabolite of methylprednisolone, in bovine tissues using LC-MS/MS is carried out for the first time. The method development demonstrates that the pH is important in optimizing the sample preparation. Tests performed using different solid-phase extraction (SPE) cartridges were enabled to produce conditions for reducing the matrix effects (ion suppression and enhancement) of analysis. Acidic condition and mixed-mode cation exchange SPE columns resulted in the most suitable clean-up for muscle and liver, and also yielded acceptable results for kidney. The enhanced sample clean-up resulted in excellent clear baselines of ion transitions, and therefore, a higher delta electron multiplier voltage (ΔEMV) could be set in the MS/MS detector. The application of 500 V of ΔEMV improved the signal responses, however, the noise level did not change, and consequently, the overall sensitivity and analytical limits (limit of detection, limit of quantification) could be enhanced. In the HPLC separation, the recently introduced Kinetex phenyl-hexyl core-shell type column was used that enabled baseline separation for dexamethasone and its β-epimer, betamethasone. Dexamethasone and betamethasone were eluted within 12 min and such reduced retention, obtained with core-shell HPLC type column, further enhanced the sensitivity. The method was validated according to the European Union (EU) 2002/657/EC Decision; the studied parameters met the EU standards. The decision limits and limit of detections were calculated in each matrix for all corticosteroids and varied from 0.01 to 13.3μg/kg and from 0.01 to 0. 1 μg/kg, respectively. PMID:22981346

  19. Analysis of methylcitrate in dried blood spots by liquid chromatography-tandem mass spectrometry.

    PubMed

    Al-Dirbashi, Osama Y; McIntosh, Nathan; McRoberts, Christine; Fisher, Larry; Rashed, Mohamed S; Makhseed, Nawal; Geraghty, Michael T; Santa, Tomofumi; Chakraborty, Pranesh

    2014-01-01

    Accumulation of propionylcarnitine (C3) in neonatal dried blood spots (DBS) is indicative of inborn errors of propionate metabolism including propionic acidemia (PA), methylmalonic aciduria (MMA), and cobalamin (Cbl) metabolic defects. Concentrations of C3 in affected newborns overlap with healthy individuals rendering this marker neither specific nor sensitive. While a conservative C3 cutoff together with relevant acylcarnitines ratios improve screening sensitivity, existing mass spectrometric methods in newborn screening laboratories are inadequate at improving testing specificity. Therefore, using the original screening DBS, we sought to measure 2-methylcitric acid (MCA), a pathognomonic hallmark of C3 disorders to decrease the false positive rate and improve the positive predictive value of C3 disorders. MCA was derivatized with 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole (DAABD-AE). No separate extraction step was required and derivatization was performed directly using a 3.2-mm disc of DBS as a sample (65°C for 45 min). The reaction mixture was analyzed by liquid chromatography tandem mass spectrometry. MCA was well separated and eluted at 2.3 min with a total run time of 7 min. The median and (range) of MCA of 0.06 μmol/L (0-0.63) were in excellent agreement with the literature. The method was applied retrospectively on DBS samples from established patients with PA, MMA, Cbl C, Cbl F, maternal vitamin B12 deficiency (n = 20) and controls (n = 337). Comparison with results obtained by another method was satisfactory (n = 252). This method will be applied as a second tier test for samples which trigger positive PA or MMA results by the primary newborn screening method. PMID:24997714

  20. Determination of bedaquiline in human serum using liquid chromatography-tandem mass spectrometry.

    PubMed

    Alffenaar, Jan-Willem C; Bolhuis, Mathieu; van Hateren, Kai; Sturkenboom, Marieke; Akkerman, Onno; de Lange, Wiel; Greijdanus, Ben; van der Werf, Tjip; Touw, Daan

    2015-09-01

    Bedaquiline, a diarylquinoline for the treatment of multidrug-resistant tuberculosis (TB), relies on exposure-dependent killing. As data on drug exposure in specific populations are scarce, pharmacokinetic studies may be of interest. No simple and robust validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been reported to date. Therefore, a new method using a quadrupole mass spectrometer was developed for analysis of bedaquiline and N-monodesmethyl bedaquiline (M2) in human serum, using deuterated bedaquiline as the internal standard. The calibration curve was linear over a range of 0.05 (lower limit of quantification [LLOQ]) to 6.00 mg/liter for both bedaquiline and M2, with correlation coefficient values of 0.997 and 0.999, respectively. The calculated accuracy ranged from 1.9% to 13.6% for bedaquiline and 2.9% to 8.5% for M2. Within-run precision ranged from 3.0% to 7.2% for bedaquiline and 3.1% to 5.2% for M2, and between-run precision ranged from 0.0% to 4.3% for bedaquiline and 0.0% to 4.6% for M2. Evaluation of serum concentrations in a patient receiving bedaquiline showed high levels at the end of treatment, reflecting accumulation of the drug. More observational pharmacokinetic data are needed to relate altered drug concentrations to clinical outcome or adverse drug effects. A simple LC-MS/MS method to quantify bedaquiline and M2 levels in human serum using a deuterated internal standard has been validated. This method can be used in clinical studies and daily practice. PMID:26149993

  1. Determination of 3-mercaptopyruvate in rabbit plasma by high performance liquid chromatography tandem mass spectrometry

    PubMed Central

    Stutelberg, Michael W.; Vinnakota, Chakravarthy V.; Mitchell, Brendan L.; Monteil, Alexandre R.; Patterson, Steven E.; Logue, Brian A.

    2014-01-01

    Accidental or intentional cyanide poisoning is a serious health risk. The current suite of FDA approved antidotes, including hydroxocobalamin, sodium nitrite, and sodium thiosulfate is effective, but each antidote has specific major limitations, such as large effective dosage or delayed onset of action. Therefore, next generation cyanide antidotes are being investigated to mitigate these limitations. One such antidote, 3-mercaptopyruvate (3-MP), detoxifies cyanide by acting as a sulfur donor to convert cyanide into thiocyanate, a relatively nontoxic cyanide metabolite. An analytical method capable of detecting 3-MP in biological fluids is essential for the development of 3-MP as a potential antidote. Therefore, a high performance liquid chromatography tandem mass spectrometry (HPLC-MS-MS) method was established to analyze 3-MP from rabbit plasma. Sample preparation consisted of spiking the plasma with an internal standard (13C3-3-MP), precipitation of plasma proteins, and reaction with monobromobimane to inhibit the characteristic dimerization of 3-MP. The method produced a limit of detection of 0.1 µM, a linear dynamic range of 0.5–100 µM, along with excellent linearity (R2 ≥ 0.999), accuracy (±9% of the nominal concentration) and precision (<7% relative standard deviation). The optimized HPLC-MS-MS method was capable of detecting 3-MP in rabbits that were administered sulfanegen, a prodrug of 3-MP, following cyanide exposure. Considering the excellent performance of this method, it will be utilized for further investigations of this promising cyanide antidote. PMID:24480329

  2. Simultaneous Quantification of Multiple Urinary Naphthalene Metabolites by Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Ayala, Daniel C.; Morin, Dexter; Buckpitt, Alan R.

    2015-01-01

    Naphthalene is an environmental toxicant to which humans are exposed. Naphthalene causes dose-dependent cytotoxicity to murine airway epithelial cells but a link between exposure and human pulmonary disease has not been established. Naphthalene toxicity in rodents depends on P450 metabolism. Subsequent biotransformation results in urinary elimination of several conjugated metabolites. Glucuronide and sulfate conjugates of naphthols have been used as markers of naphthalene exposure but, as the current studies demonstrate, these assays provide a limited view of the range of metabolites generated from the parent hydrocarbon. Here, we present a liquid chromatography tandem mass spectrometry method for measurement of the glucuronide and sulfate conjugates of 1-naphthol as well as the mercapturic acids and N-acetyl glutathione conjugates from naphthalene epoxide. Standard curves were linear over 2 log orders. On column detection limits varied from 0.91 to 3.4 ng; limits of quantitation from 1.8 to 6.4 ng. The accuracy of measurement of spiked urine standards was -13.1 to + 5.2% of target and intra-day and inter-day variability averaged 7.2 (± 4.5) and 6.8 (± 5.0) %, respectively. Application of the method to urine collected from mice exposed to naphthalene at 15 ppm (4 hrs) showed that glutathione-derived metabolites accounted for 60-70% of the total measured metabolites and sulfate and glucuronide conjugates were eliminated in equal amounts. The method is robust and directly measures several major naphthalene metabolites including those derived from glutathione conjugation of naphthalene epoxide. The assays do not require enzymatic deconjugation, extraction or derivatization thus simplifying sample work up. PMID:25853821

  3. Quantitative analysis of glycerol levels in human urine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Dong, Ying; Ma, Yanhua; Yan, Kuan; Shen, Li; Wang, Xiaobing; Xu, Youxuan; He, Genye; Wu, Yun; Lu, Jianghai; Yang, Zhiyong; Feng, Feifei

    2014-04-15

    Glycerol has the latent capacity to act as a plasma volume expander and disguise blood doping practices. Therefore, it has been prohibited in sports as a masking agent by the World Anti-Doping Agency (WADA) since January 2010 and a urinary threshold (1mg/mL) was recommended recently [1]. The purpose of this study was to establish and validate a novel quantitative method for the determination of urinary glycerol concentrations using a liquid chromatography-tandem mass spectrometry approach. This simple yet highly specific method made use of the derivatization of glycerol by benzoyl chloride in aqueous solution at 40°C followed by analysis via LC-ESI-MS/MS without sample pre-concentration or cleanup. The assay was linear over the concentration range of 1.0-1000μg/mL for glycerol in human urine. The lower limit of detection (LLOD) and lower limit of quantitation (LLOQ) were 0.3μg/mL and 1.0μg/mL, respectively. The intra- and inter-day precision of the method at three concentration levels (3, 500 and 900μg/mL) was less than 12.2%. The method also afforded satisfactory results in terms of accuracy, derivatization yield, extraction recovery, matrix effect and specificity. The method has been successfully applied to the detection of glycerol in "Quality Assurance Program" samples provided by the World Association of Anti-Doping Scientists (WAADS) and routine doping-control samples in our laboratory. PMID:24657408

  4. Simultaneous determination of 3-mercaptopyruvate and cobinamide in plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    Stutelberg, Michael W; Dzisam, Joseph K; Monteil, Alexandre R; Petrikovics, Ilona; Boss, Gerry R; Patterson, Steven E; Rockwood, Gary A; Logue, Brian A

    2016-01-01

    The current suite of Food and Drug Administration (FDA) approved antidotes (i.e., sodium nitrite, sodium thiosulfate, and hydroxocobalamin) are effective for treating cyanide poisoning, but individually, each antidote has major limitations (e.g., large effective dosage or delayed onset of action). To mitigate these limitations, next-generation cyanide antidotes are being investigated, including 3-mercaptopyruvate (3-MP) and cobinamide (Cbi). Analytical methods capable of detecting these therapeutics individually and simultaneously (for combination therapy) are essential for the development of 3-MP and Cbi as potential cyanide antidotes. Therefore, a liquid chromatography-tandem mass-spectrometry method for the simultaneous analysis of 3-MP and Cbi was developed. Sample preparation of 3-MP consisted of spiking plasma with an internal standard ((13)C3-3-MP), precipitation of plasma proteins, and derivatizing 3-MP with monobromobimane to produce 3-mercaptopyruvate-bimane. Preparation of Cbi involved denaturing plasma proteins with simultaneous addition of excess cyanide to convert each Cbi species to dicyanocobinamide (Cbi(CN)2). The limits of detection for 3-MP and Cbi were 0.5μM and 0.2μM, respectively. The linear ranges were 2-500μM for 3-MP and 0.5-50μM for Cbi. The accuracy and precision for 3-MP were 100±9% and <8.3% relative standard deviation (RSD), respectively. For Cbi(CN)2, the accuracy was 100±13% and the precision was <9.5% RSD. The method presented here was used to determine 3-MP and Cbi from treated animals and may ultimately facilitate FDA approval of these antidotes for treatment of cyanide poisoning. PMID:26655110

  5. Multiresidue analysis of pesticides with hydrolyzable functionality in cooked vegetables by liquid chromatography tandem mass spectrometry.

    PubMed

    Lee, Sung Joong; Park, Semin; Choi, Jin Young; Shim, Jae-Han; Shin, Eun-Ho; Choi, Jeong-Heui; Kim, Soo Taek; Abd El-Aty, A M; Jin, Jong Sung; Bae, Dong Won; Shin, Sung Chul

    2009-07-01

    It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean-up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB-C(18) column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100gamma(ij) (%). A high matrix effect (<-30%) was detected for the seven polar pesticides, namely thiamethoxam, clothianidin, acetamiprid, aldicarb, thiacloprid, pirimicarb and methabenzthiazuron. The limits of detection were in the range of 0.1-8.1 microg/kg, indicating a good sensitivity. Most of the recoveries ranged from 70 to 131% with RSDs

  6. Screening of anabolic steroids in horse urine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Yu, Nola H; Ho, Emmie N M; Leung, David K K; Wan, Terence S M

    2005-04-29

    Anabolic steroids have the capability of improving athletic performance and are banned substances in the Olympic games as well as in horseracing and equestrian competitions. The control of their abuse in racehorses is traditionally performed by detecting the presence of anabolic steroids and/or their metabolite(s) in urine samples using gas chromatography-mass spectrometry (GC-MS). However, this approach usually requires tedious sample processing and chemical derivatisation steps and could be very insensitive in detecting certain steroids. This paper describes a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method for the detection of anabolic steroids that are poorly covered by GC-MS. Enzyme-treated urine was processed by solid-phase extraction (SPE) using a Bond Elut Certify cartridge, followed by a base wash for further cleanup. Separation of the steroids was carried out on a reversed-phase DB-8 column using 0.1% acetic acid and methanol as the mobile phase in a gradient elution programme. The mass spectrometer for the detection of the steroids was operated in the positive electrospray ionisation (ESI) mode with multiple reaction monitoring (MRM). Urine samples fortified with 15 anabolic steroids (namely, androstadienone, 1-androstenedione, bolasterone, boldione, 4-estrenedione, gestrinone, methandrostenolone, methenolone, 17alpha-methyltestosterone, norbolethone, normethandrolone, oxandrolone, stenbolone, trenbolone and turinabol) at low ng/mL levels were consistently detected. No significant matrix interference was observed at the retention times of the targeted ion masses in blank urine samples. The method specificity, sensitivity, precision, recoveries, and the performance of the enzyme hydrolysis step were evaluated. The successful application of the method to analyse methenolone acetate administration urine samples demonstrated that the method could be effective in detecting anabolic steroids and their metabolites in horse

  7. Determination of macrocyclic lactone drug residues in animal muscle by liquid chromatography/tandem mass spectrometry.

    PubMed

    He, Limin; Zhao, Donghao; Su, Yijuan; Liu, Yahong; Nie, Jianrong; Lian, Jin

    2009-01-01

    A robust, credible, and practical multiresidue method based on liquid chromatography/tandem/mass spectrometry (LC/MS/MS) was developed for the simultaneous determination of 9 macrocyclic lactone drugs (abamectin B1a, doramectin, erythromycin, ivermectin B1a, josamycin, kitasamycin, roxithromycin, tilmicosin, and tylosin A) in bovine, porcine, chicken, and sheep muscles. The drugs were extracted with acetonitrile, and the extracts were defatted with n-hexane and further cleaned up on a C18 solid-phase extraction cartridge. LC/MS/MS data acquisition was achieved by using the multiple-reaction monitoring (MRM) mode, i.e., 2 transitions, to provide a high degree of sensitivity and repeatability. Matrix-matched standard calibration curves were used to achieve the best accuracy of the method by compensating for the matrix effect. The calibration graphs were linear (r > 0.998) from 10 to 1000 ng/mL for erythromycin, josamycin, kitasamycin, roxithromycin, tilmicosin, and tylosin, and from 5 to 250 ng/mL for abamectin, doramectin, and ivermectin. The average recoveries of the 9 drugs were between 64.5 and 105%, calculated by using matrix-matched calibration, with relative standard deviation values ranging from 1.6 to 14%. The limits of detection were 0.1 microg/kg for erythromycin, josamycin, roxithromycin, and tylosin; 0.2 microg/kg for tilmicosin and kitasamycin; and 0.5 microg/kg for abamectin, doramectin, and ivermectin. For confirmation, the MRM ratios for the 9 drug residues in the samples and the solvent were evaluated and found to be within the ratio criteria set by the guidelines of the European Union. PMID:19382593

  8. Liquid chromatography-tandem mass spectrometry method for the determination of anthelmintics in alfalfa plants.

    PubMed

    Islam, M Dabalus; Haberhauer, G; Gerzabek, M; Cannavan, A

    2012-01-01

    A simple and inexpensive liquid chromatography-tandem mass spectrometric method for the determination of anthelmintics in alfalfa plants (Medicago sativa L.) was developed and validated. Anthelmintics in plant leaves and stems (green chops) were extracted with methanol/acetonitrile (7:3, v/v) followed by a concentration and clean-up step using solid-phase extraction (Strata-X, 500 mg, 6 ml cartridge). After drying with nitrogen gas, the adsorbed analytes were eluted with methanol/acetonitrile (50:50, v/v) mixture followed by 100% acetonitrile. Chromatographic separation was achieved on an Atlantis T-3 (2.1 × 100 mm × 3 µm) analytical column with a Phenomenex guard cartridge (C8, 4 × 3 mm) attached to a Waters triple quadrupole mass spectrometer operated in positive electrospray ionisation mode with selected reaction monitoring. Samples were analysed using gradient elution at a flow rate of 0.35 ml min⁻¹. The mobile phase consisted of a 10 mM ammonium formate solution in (A) water/acetonitrile (90:10, v/v) and (B) methanol/acetonitrile (50:50, v/v). The method was validated for levamisole, fenbendazole, fenbendazole sulphoxide and fenbendazole sulphone at 10, 20 and 40 µg kg⁻¹ and for eprinomectin at 20, 40 and 80 µg kg⁻¹. Limits of quantification (LOQ) were 10 µg kg⁻¹ for all analytes except eprinomectin, which had an LOQ of 20 µg kg⁻¹. The overall mean recovery in green plants was between 74.2% and 81.4% with repeatabilities ranging from 2.2% to 19.1% and reproducibilities in the range 3.8-8.7%. The validated method was applied to plant samples in a study on the behaviour of anthelmintic drugs in a soil, plant and water system. PMID:22827314

  9. Fluoroquinolone residues in compost by green enhanced microwave-assisted extraction followed by ultra performance liquid chromatography tandem mass spectrometry.

    PubMed

    Speltini, Andrea; Sturini, Michela; Maraschi, Federica; Viti, Simona; Sbarbada, Davide; Profumo, Antonella

    2015-09-01

    A novel, simple and straightforward method for determination of fluoroquinolones (FQs) in compost has been developed. The procedure entails a low-pressurized microwave-assisted extraction (MAE) carried out by a high performance instrument, in alkaline aqueous solution containing magnesium ions as FQs complexing agent, followed by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS). Ciprofloxacin (CIP), Enrofloxacin (ENR), Levofloxacin (LEV) and Norfloxacin (NOR), four widely used FQ antibiotics, were simultaneously extracted from compost by a single MAE cycle (20min, 135°C). The method was validated in terms of linearity, selectivity, sensitivity and accuracy. Quantitative absolute recovery (70-112%, n=3) and suitable precision (RSD<15%, n=3) were observed, at concentration levels ranging from 25 ng g(-1) to 2500 ng g(-1). Analytes were separated in a 10min chromatographic run and quantified/confirmed in single reaction monitoring (SRM) mode. UPLC coupled to SRM-MS detection allowed to achieve improved sensitivity, and selective detection. Method detection and quantification limits, MDLs and MQLs, were in the range 2.2-3.0 ng g(-1) and 6.6-9.0 ng g(-1), respectively. The high-performance microwave system here used strongly improved the extraction efficiency with respect to a conventional apparatus. The procedure proved to be simpler, less expensive, faster, and more green with respect to the few methods currently described in literature, providing at the same time suitable recovery and reproducibility. The analytical method has been applied to the analysis of actual compost samples, wherein FQs have been quantified at concentrations up to 88 ng g(-1). PMID:26250963

  10. Sample preparation and liquid chromatography-tandem mass spectrometry for multiple steroids in mammalian and avian circulation.

    PubMed

    Koren, Lee; Ng, Ella S M; Soma, Kiran K; Wynne-Edwards, Katherine E

    2012-01-01

    Blood samples from wild mammals and birds are often limited in volume, allowing researchers to quantify only one or two steroids from a single sample by immunoassays. In addition, wildlife serum or plasma samples are often lipemic, necessitating stringent sample preparation. Here, we validated sample preparation for simultaneous liquid chromatography--tandem mass spectrometry (LC-MS/MS) quantitation of cortisol, corticosterone, 11-deoxycortisol, dehydroepiandrosterone (DHEA), 17β-estradiol, progesterone, 17α-hydroxyprogesterone and testosterone from diverse mammalian (7 species) and avian (5 species) samples. Using 100 µL of serum or plasma, we quantified (signal-to-noise (S/N) ratio ≥ 10) 4-7 steroids depending on the species and sample, without derivatization. Steroids were extracted from serum or plasma using automated solid-phase extraction where samples were loaded onto C18 columns, washed with water and hexane, and then eluted with ethyl acetate. Quantitation by LC-MS/MS was done in positive ion, multiple reaction-monitoring (MRM) mode with an atmospheric pressure chemical ionization (APCI) source and heated nebulizer (500°C). Deuterated steroids served as internal standards and run time was 15 minutes. Extraction recoveries were 87-101% for the 8 analytes, and all intra- and inter-run CVs were ≤ 8.25%. This quantitation method yields good recoveries with variable lipid-content samples, avoids antibody cross-reactivity issues, and delivers results for multiple steroids. Thus, this method can enrich datasets by providing simultaneous quantitation of multiple steroids, and allow researchers to reimagine the hypotheses that could be tested with their volume-limited, lipemic, wildlife samples. PMID:22384262

  11. Simultaneous pharmacokinetic and pharmacodynamic analysis of 5α-reductase inhibitors and androgens by liquid chromatography tandem mass spectrometry.

    PubMed

    Upreti, Rita; Naredo, Gregorio; Faqehi, Abdullah M M; Hughes, Katherine A; Stewart, Laurence H; Walker, Brian R; Homer, Natalie Z M; Andrew, Ruth

    2015-01-01

    Benign prostatic hyperplasia and prostate cancer can be treated with the 5α-reductase inhibitors, finasteride and dutasteride, when pharmacodynamic biomarkers are useful in assessing response. A novel method was developed to measure the substrates and products of 5α-reductases (testosterone, 5α-dihydrotestosterone (DHT), androstenedione) and finasteride and dutasteride simultaneously by liquid chromatography tandem mass spectrometry, using an ABSciex QTRAP(®) 5500, with a Waters Acquity™ UPLC. Analytes were extracted from serum (500 µL) via solid-phase extraction (Oasis(®) HLB), with (13)C3-labelled androgens and d9-finasteride included as internal standards. Analytes were separated on a Kinetex C18 column (150 × 3 mm, 2.6 µm), using a gradient run of 19 min. Temporal resolution of analytes from naturally occurring isomers and mass +2 isotopomers was ensured. Protonated molecular ions were detected in atmospheric pressure chemical ionisation mode and source conditions optimised for DHT, the least abundant analyte. Multiple reaction monitoring was performed as follows: testosterone (m/z 289 → 97), DHT (m/z 291 → 255), androstenedione (m/z 287 → 97), dutasteride (m/z 529 → 461), finasteride (m/z 373 → 317). Validation parameters (intra- and inter-assay precision and accuracy, linearity, limits of quantitation) were within acceptable ranges and biological extracts were stable for 28 days. Finally the method was employed in men treated with finasteride or dutasteride; levels of DHT were lowered by both drugs and furthermore the substrate concentrations increased. PMID:25281165

  12. Novel rapid liquid chromatography tandem masspectrometry method for vemurafenib and metabolites in human plasma, including metabolite concentrations at steady state.

    PubMed

    Vikingsson, Svante; Strömqvist, Malin; Svedberg, Anna; Hansson, Johan; Höiom, Veronica; Gréen, Henrik

    2016-08-01

    A novel, rapid and sensitive liquid chromatography tandem-mass spectrometry method for quantification of vemurafenib in human plasma, that also for the first time allows for metabolite semi-quantification, was developed and validated to support clinical trials and therapeutic drug monitoring. Vemurafenib was analysed by precipitation with methanol followed by a 1.9 min isocratic liquid chromatography tandem masspectrometry analysis using an Acquity BEH C18 column with methanol and formic acid using isotope labelled internal standards. Analytes were detected in multireaction monitoring mode on a Xevo TQ. Semi-quantification of vemurafenib metabolites was performed using the same analytical system and sample preparation with gradient elution. The vemurafenib method was successfully validated in the range 0.5-100 μg/mL according to international guidelines. The metabolite method was partially validated owing to the lack of commercially available reference materials. For the first time concentration levels at steady state for melanoma patients treated with vemurafenib is presented. The low abundance of vemurafenib metabolites suggests that they lack clinical significance. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26683023

  13. Pressurized liquid extraction with in-cell clean-up followed by gas chromatography-tandem mass spectrometry for the selective determination of parabens and triclosan in indoor dust.

    PubMed

    Canosa, P; Pérez-Palacios, D; Garrido-López, A; Tena, M T; Rodríguez, I; Rubí, E; Cela, R

    2007-08-17

    A sample preparation method based on the use of pressurized liquid extraction is proposed for the determination of four alkyl parabens and triclosan in indoor dust. Extraction of analytes and removal of interfering species were achieved in the same step, by placing an appropriate sorbent in the extraction cell and by choosing a right combination of washing and elution solvents. Compounds, as silylated derivatives, were determined by gas chromatography in combination with tandem mass spectrometry (GC-MS/MS). Factors affecting the yield and selectivity of the sample preparation procedure were carefully evaluated. Under final conditions, dried samples (0.5 g of dust and 1g of sodium sulphate) were dispersed with 3g of Florisil and loaded into an 11 mL stainless-steel extraction cell containing 1g of the same material as clean-up sorbent. Non-polar species were removed with n-hexane under mild conditions (40 degrees C, 3.4 MPa) and then analytes were extracted with ethyl acetate. The best compromise extraction conditions were 103 degrees C, 13.8 MPa and 3 static extraction cycles of 1 min. The proposed method provided recoveries from 76 to 98%, relative standard deviations under 11% (operating under reproducibility conditions) and quantification limits from 1 to 4 ng/g. The analysis of dust samples from private houses and office buildings confirmed the ubiquitous presence of target bacteriocides in these environments. PMID:17585923

  14. Pharmacokinetic analysis of levo-tetrahydropalmatine in rabbit plasma by rapid sample preparation and liquid chromatography-tandem mass spectrometry.

    PubMed

    Tran, Son Cao; Duc, Nguyen Dinh; Tung, Nguyen-Thach

    2016-01-01

    A rapid extraction method was developed and validated for levo-tetrahydropalmatine (l-THP) determination in rabbit plasma by liquid chromatography tandem-mass spectrometry (LC-MS/MS). The sample preparation included a single-step acetonitrile extraction and salting out liquid-liquid partitioning from the water in plasma with MgSO4. Berberine was used as internal standard. The mass spectrometry source was negative electrospray ionization. The method showed good performance in the concentration range from 5 to 200ngmL(-1). The limit of quantification (LOQ) was 1ngmL(-1). The method was successfully applied to a pharmacokinetic study in rabbit comparing the two drug formulation of l-THP including the raw material and the self-microemulsifying drug delivery system pellet. PMID:26638032

  15. Routine approach to qualitatively screen for 300 pesticides and quantify those frequently detected in fruits and vegetables using liquid chromatography tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes an efficient and effective analytical scheme to first screen for 300 pesticides in fruit and vegetables samples using liquid chromatography tandem mass spectrometry (LC-MS/MS) with a commercial enhanced product ion method. Then, the presumed positive extracts were analyzed using...

  16. METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

    EPA Science Inventory

    Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

  17. The use of liquid chromatography tandem mass spectrometry to detect proteins in saliva from horses with and without systemic inflammation.

    PubMed

    Jacobsen, Stine; Top Adler, Ditte Marie; Bundgaard, Louise; Sørensen, Mette Aamand; Andersen, Pia Haubro; Bendixen, Emøke

    2014-12-01

    The objective of the study was to assess global expression of proteins in equine saliva using liquid chromatography tandem mass spectrometry (LC-MS/MS). Saliva was obtained from seven horses with and six horses without evidence of systemic inflammatory disease. Tryptic peptides from saliva were analysed by LC-MS/MS. Of 195 unique proteins identified, 57 were detected only in saliva samples from horses with systemic inflammation (in two to six of the seven horses). Among the differentially expressed proteins were several acute phase proteins (APPs) such as serum amyloid A, fibrinogen, haptoglobin, and alpha1-acid glycoprotein. The study is the first to describe detection of inflammatory proteins in horse saliva. The proteins detected were similar to those described in saliva from cattle, small ruminants and pigs. Detection of APPs in horses with systemic inflammation suggests that saliva may be used for non-invasive disease monitoring in horses as in humans, pigs and dogs. PMID:25296850

  18. Development, validation and determination of multiclass pesticide residues in cocoa beans using gas chromatography and liquid chromatography tandem mass spectrometry.

    PubMed

    Zainudin, Badrul Hisyam; Salleh, Salsazali; Mohamed, Rahmat; Yap, Ken Choy; Muhamad, Halimah

    2015-04-01

    An efficient and rapid method for the analysis of pesticide residues in cocoa beans using gas and liquid chromatography-tandem mass spectrometry was developed, validated and applied to imported and domestic cocoa beans samples collected over 2 years from smallholders and Malaysian ports. The method was based on solvent extraction method and covers 26 pesticides (insecticides, fungicides, and herbicides) of different chemical classes. The recoveries for all pesticides at 10 and 50 μg/kg were in the range of 70-120% with relative standard deviations of less than 20%. Good selectivity and sensitivity were obtained with method limit of quantification of 10 μg/kg. The expanded uncertainty measurements were in the range of 4-25%. Finally, the proposed method was successfully applied for the routine analysis of pesticide residues in cocoa beans via a monitoring study where 10% of them was found positive for chlorpyrifos, ametryn and metalaxyl. PMID:25442595

  19. Analysis of pesticide multi-residues in leafy vegetables by ultrasonic solvent extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Pan, Jian; Xia, Xiao-Xiao; Liang, Juan

    2008-01-01

    Ultrasonic solvent extraction (USE) of pesticide multi-residues including monocrotophos, dimethoate, imidacloprid, carbendazim, carbaryl and simazine from leafy vegetables is presented. The extraction procedure was optimized with regard to the solvent type and amount, sonication time and number of extraction steps. The extract did not need clean-up before injected into liquid chromatography-tandem mass spectrometry (LC-MS-MS) which was employed together with electron microscope to verify the effect of USE method. The proposed procedure allows the extraction of six pesticide residues in a single step with 40 ml of ethyl acetate for 35 min sonication, providing recovery over 83% and LOQ less than 1.4 microg/kg. The optimized USE method is a simple, low cost and an effective preparation method for determination of pesticide multi-residues at trace levels in leafy vegetables in comparison with homogenized extraction method. PMID:17664080

  20. Determination of chokeberry (Aronia melanocarpa) polyphenol components using liquid chromatography-tandem mass spectrometry: Overall contribution to antioxidant activity.

    PubMed

    Lee, Ji Eun; Kim, Gon-Sup; Park, Semin; Kim, Yun-Hi; Kim, Man-Bae; Lee, Won Sup; Jeong, Sung Woo; Lee, Soo Jung; Jin, Jong Sung; Shin, Sung Chul

    2014-03-01

    The type and content of plant polyphenols can be influenced by maturity. Korean chokeberry (Aronia melanocarpa) leaves of three different maturities (young, mature, and aged) were extracted with 70% aqueous methanol. The polyphenols in the leaves were analysed for the first time using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and comparison with reported data. Among the 12 characterised components, five flavonoids, 3, 4, and 10-12, and a dicaffeoylquinic acid derivative, 6, were characterised for the first time in chokeberry leaves. Each polyphenol component was validated and quantified using a representative polyphenol standard of the same group. The antioxidant activity of the three different mature leaf extracts was determined. The antioxidant activity was highest for young leaves, followed by mature and aged leaves. The results suggest that younger chokeberry leaves may be more favourable for processing a higher quality functional tea due to their higher polyphenol content. PMID:24176305

  1. Residue analysis of fipronil and difenoconazole in okra by liquid chromatography tandem mass spectrometry and their food safety evaluation.

    PubMed

    Hingmire, Sandip; Oulkar, Dasharath P; Utture, Sagar C; Ahammed Shabeer, T P; Banerjee, Kaushik

    2015-06-01

    A liquid chromatography tandem mass spectrometry (LC-MS/MS) based method is reported for simultaneous analysis of fipronil (plus its metabolites) and difenoconazole residues in okra. The sample preparation method involving extraction with ethyl acetate provided 80-107% recoveries for both the pesticides with precision RSD within 4-17% estimated at the limits of quantification (LOQ, fipronil=1ngg(-1), difenoconazole=5ngg(-1)) and higher fortification levels. In field, both the pesticides dissipated with half-life of 2.5days. The estimated pre-harvest intervals (PHI) for fipronil and difenoconazole were 15 and 19.5days, and 4 and 6.5days at single and double dose of field applications, respectively. Decontamination of incurred residues by washing and different cooking treatments was quite efficient in minimizing the residue load of both the chemicals. Okra samples harvested after the estimated PHIs were found safe for human consumption. PMID:25624217

  2. [Simultaneous determination of six synthetic sweeteners in food by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Liu, Xiaoxi; Ding, Li; Liu, Jinxia; Zhang, Ying; Huang, Zhiqiang; Wang, Libing; Chen, Bo

    2010-11-01

    A simple and sensitive method for the determination of six synthetic sweeteners (sodium cyclamate, saccharin sodium, acesulfame-K, aspartame, alitame and neotame) in food was developed. The synthetic sweeteners were extracted by methanol-water (1 : 1, v/v). The extract was separated on a C18 column using 0.1% (v/v) formic acid-5 mmol/L ammonium formate/acetonitrile as mobile phase, and then detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using multiple reaction monitoring (MRM) mode. The good linearities (r > 0.998) were achieved for all the analytes over the range of 20-500 microg/L. The recoveries obtained ranged from 81.3% to 106.0% at three spiked concentrations, with the relative standard deviations lower than 11%. The established method has been successfully applied to the determination of synthetic sweeteners in food. PMID:21381416

  3. Characterization of aromatase binding agents from the dichloromethane extract of Corydalis yanhusuo using ultrafiltration and liquid chromatography tandem mass spectrometry.

    PubMed

    Shi, Jing; Zhang, Xiaoyu; Ma, Zhongjun; Zhang, Min; Sun, Fang

    2010-05-01

    Aromatase represents an important target for the treatment of hormone-dependent breast cancer. In the present study, nine alkaloids from the dichloromethane extract of Corydalis yanhusuo were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS) and tested for their aromatase binding activities using an ultrafiltration LC-MS method by investigating the differences of peak areas of compounds before and after incubations with aromatase. It was demonstrated that the quaternary protoberberine alkaloids and the tertiary protoberberine alkaloids exhibited potent aromatase binding activities. The quaternary ammonium group and the methyl group at C-13 position of tertiary protoberberine alkaloids might be necessary for the activity. The findings should provide guidance for the discovery of potential aromatase inhibitors from natural products. PMID:20657498

  4. In vivo and in vitro metabolism of aspirin eugenol ester in dog by liquid chromatography tandem mass spectrometry.

    PubMed

    Shen, Youming; Liu, Xiwang; Yang, Yajun; Li, Jianyong; Ma, Ning; Li, Bing

    2015-01-01

    Aspirin eugenol ester (AEE) is a promising drug candidate for treatment of inflammation, pain and fever and prevention of cardiovascular diseases with fewer side effects than its precursor, aspirin. Investigation into its metabolic process in target animal species will help to illustrate its mechanism of action and to establish its residual mark compound to formulate its dosage. Six beagle dogs were orally given a dose of 20 mg kg(-1) of AEE and one dog was used to prepare blank liver microsomes. Their liver microsomes were prepared for in vitro study and their plasma and urine were collected for in vivo metabolic analysis using liquid chromatography tandem mass spectrometry. In this study we identified 10 metabolites, M1, M2, M3, M4, M5 in phase I and M6, M7, M8, M9, M10 in phase II. Based on the metabolites of AEE, the pathways of AEE metabolism in dog were demonstrated. PMID:24935248

  5. Identification of monomenthyl succinate, monomenthyl glutarate, and dimenthyl glutarate in nature by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Hiserodt, Richard D; Adedeji, Jide; John, T V; Dewis, Mark L

    2004-06-01

    Menthol, menthone, and other natural compounds provide a cooling effect and a minty flavor and have found wide application in chewing gum and oral care products. Monomenthyl succinate, monomenthyl glutarate, and dimenthyl glutarate provide a cooling effect without the burning sensation associated with menthol. Additionally, because they do not have a distinct flavor, they can be used in applications other than mint flavors. Because these menthyl esters have not been reported in nature, we undertook to identify a natural source for these cooling compounds. Using high performance liquid chromatography-tandem mass spectrometry, monomenthyl succinate was identified in Lycium barbarum and Mentha piperita, and monomenthyl glutarate and dimenthyl glutarate were identified in Litchi chinesis. The identifications were based on the correlation of mass spectrometric and chromatographic retention time data for the menthyl esters in the extracts with authentic standards which resulted in a 99.980% confidence in the identifications. PMID:15161227

  6. Analysis of 10 systemic pesticide residues in various baby foods using liquid chromatography-tandem mass spectrometry.

    PubMed

    Yang, Angel; Abd El-Aty, A M; Park, Jong-Hyouk; Goudah, Ayman; Rahman, Md Musfiqur; Do, Jung-Ah; Choi, Ok-Ja; Shim, Jae-Han

    2014-06-01

    Ten systemic pesticides, comprising methomyl, thiamethoxam, acetamiprid, carbofuran, fosthiazate, metalaxyl, azoxystrobin, diethofencarb, propiconazole, and difenoconazole, were detected in 13 baby foods (cereals, boiled potatoes, fruit and milk) using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for sample preparation and liquid chromatography tandem mass spectrometry for analysis. The matrix-matched calibration curves showed good linearity with determination coefficients (R(2) ) >0.992. The limits of detection and quantitation were 0.0015-0.003 and 0.005-0.01 mg/kg, respectively. The mean recoveries of three different concentrations ranged from 69.2 to 127.1% with relative standard deviations <20%. The method was successfully applied to 13 actual samples collected from a local market, and none of the samples were found to contain pesticide residues. This method is suitable for the identification and quantification of systemic pesticides with matrix-matched standards in various baby foods. PMID:24861738

  7. Simultaneous determination of fluoroquinolones in foods of animal origin by a high performance liquid chromatography and a liquid chromatography tandem mass spectrometry with accelerated solvent extraction.

    PubMed

    Yu, Huan; Tao, Yanfei; Chen, Dongmei; Pan, Yuanhu; Liu, Zhenli; Wang, Yulian; Huang, Lingli; Dai, Menghong; Peng, Dapeng; Wang, Xu; Yuan, Zonghui

    2012-02-15

    A confirmatory and quantitative method based on a high performance liquid chromatography UV detector (HPLC-UV) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) with an extraction procedure of accelerated solvent extraction (ASE) has been developed for simultaneous determination of 15 kinds of fluoroquinolones in various animal origin food samples. The sample preparation procedures consist of an extraction step with acetonitrile and a cleaning-up step with Oasis HLB cartridge. Parameters for extraction pressure and temperature, cycle of ASE, clean-up, and analysis procedure have been optimized systematically. The recoveries of FQNs spiked in the tissues as the muscle, liver, kidney of swine, bovine, chicken and fish at a concentration range of 10-800μg/kg were found between 70.6% and 111.1% with relative standard deviations (RSD) less than 15% in HPLC. The LOD and LOQ of the HPLC for the 15 FQNs were 3μg/kg and 10μg/kg, respectively, and those of the LC-MS/MS were 0.3 and 1μg/kg, respectively. These rapid and reliable methods can be used to efficiently separate, characterize and quantify the residues of 15 FQNs (Marbofloxacin, Enoxacin, Fleroxacin, Ofloxacin, Pefloxacin, Lomefloxacin, Danofloxacin, Enrofloxacin, Orbifloxacin, Cinoxacin, Gatifloxacin, Sarafloxacin, Difloxacin, Nalidixic Acid, Flumequine) in food of animal origin. PMID:22230742

  8. Simultaneous determination of six phenolic constituents of danshen in human serum using liquid chromatography/tandem mass spectrometry.

    PubMed

    Li, Xiaochuan; Yu, Chen; Cai, Yongbao; Liu, Gangyi; Jia, Jingying; Wang, Yiping

    2005-06-01

    The six phenolic constituents are water-soluble components extracted from the Chinese medical herb danshen, the dried roots of Salvia miltiorrhiza Bunge (Labiatae). An liquid chromatography/tandem mass spectrometry (LC/MS/MS)-based method has been developed for the simultaneous quantification of six phenolic constituents of danshen (magnesium lithospermate B (MLB), rosmarinic acid (RA) and lithospermic acid (LA), caffeic acid (CAA), protocatechuic aldehyde (3,4-dihydroxybenzaldehyde, Pal), 3,4-dihydroxyphenyllactic acid (danshensu)) in human serum with chloramphenicol as internal standard. The serum samples were treated by special liquid-liquid extraction, and the analytes were determined using electrospray negative ionization mass spectrometry in the multiple reaction monitoring (MRM) mode, with sufficient sensitivity to allow analysis of human serum samples generated following administration of a clinically relevant dose. Good linearity over the range 8-2048 ng/mL for six phenolic constituents was observed. The intra- and inter-day precisions (CV) of analysis were <13%, and the accuracy ranged from 88 to 116%. This quantitation method was successfully applied to a pharmacokinetic study of i.v. drip infusion of Danshen injection fluid in human. PMID:15866491

  9. [Determination of 16 pesticide residues in fruits and vegetables by QuEChERS-liquid chromatography-tandem mass spectrometry].

    PubMed

    Wu, Yan; Jiang, Bing; Xu, Yigang; Zhao, Wei; Meng, Xiangrui; Zhou, Yuan; Yu, Jiahui; Zu, Yuangang

    2015-03-01

    A sensitive and convenient liquid chromatography-tandem mass spectrometric method was developed for the determination of 16 pesticides such as imidacloprid, prochloraz, difenoconazole, azoxystrobin, and thiamethoxam in fruits and vegetables. After compared with methanol and acetone-cyclohexane (1:2, v/v), acetonitrile was chosen as the extraction solvent. The samples were extracted by acetonitrile in high-speed homogenization. The extraction solution was cleaned up by liquid-liquid extraction, and the supernatant was collected. In this work, QuEChERS exhibited much higher efficiency than Carbon-NH2 solid-phase extraction in purification. The pigments and organic acids were removed by purge line (150 mg primary secondary amine (PSA) sorbent and 900 mg absolute magnesium sulfate), leading to the decrease of the background interferences. The average recoveries of the 16 pesticides were almost in the range of 75%-111% at the three spiked levels, and the relative standard deviations were less than 16%. The qualitative analysis and quantitative analysis were investigated by LC-MS/MS and matrix-matched calibration curves. The results showed that the method of QuEChERS combined with LC-MS/MS is rapid, accurate and sensitive for the determination of the 16 pesticide residues in fruits and vegetables. PMID:26182463

  10. Screening and quantitative determination of twelve acidic and neutral pharmaceuticals in whole blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Simonsen, Kirsten Wiese; Steentoft, Anni; Buck, Maike; Hansen, Lene; Linnet, Kristian

    2010-09-01

    We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry. The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil, but these drugs were not included in the full validation program and are not described in detail here. Limit of quantitation was 1 mg/kg for the compounds with coefficients of variation of < 20%, except for furosemide, which had a coefficient of variation of 32% at limit of quantitation. The measuring interval was wide for most components. Extraction efficiencies were high, reflecting the high-yield capacity of the method. PMID:20822673

  11. Liquid chromatography-tandem mass spectrometric assay for the light sensitive survivin suppressant sepantronium bromide (YM155) in mouse plasma.

    PubMed

    Dolman, M Emmy M; den Hartog, Ilona J M; Molenaar, Jan J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2014-04-01

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for sepantronium bromide (YM155), an inhibitor of survivin, was developed and validated. Under reduced light exposure, plasma samples were pre-treated using protein precipitation with acetonitrile containing AT7519 as internal standard. After dilution with water, the extract was directly injected into the reversed-phase liquid chromatographic system. The eluate was transferred into the electrospray interface with positive ionization and compounds detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was validated in a 0.5-100ng/ml calibration range with r(2)=0.9981±0.0007 using double logarithmic calibration (n=5). Within day precisions (n=6) were 3.6-8.8% and between day (3 days; n=18) precisions 6.5-11.1%. Accuracies were between 92 and 111% for the whole calibration range. The light sensitive drug sepantronium was sufficiently stable under all relevant analytical conditions. Finally, the assay was successfully used to determine plasma drug levels in mice after administration of sepantronium bromide by continuous infusion from subcutaneously implanted osmotic pumps. PMID:24518133

  12. Strategies to in vitro assessment of major human CYP enzyme activities by using liquid chromatography tandem mass spectrometry.

    PubMed

    Lahoz, A; Donato, M T; Castell, J V; Gómez-Lechón, M J

    2008-01-01

    At the early stage of drug discovery, thousands of new chemical entities (NCEs) may be screened before a single candidate can be identified for development. Determining the role of CYP enzymes in the metabolism of a compound and evaluating the effect of NCEs on human CYP activities are key issues in pharmaceutical development as they may explain inter-subject variability, drug-drug interactions, non-linear pharmacokinetics and toxic effects. Reliable methods for determining enzyme activities are needed to characterize an individual CYP enzyme and to obtain a tool for the evaluation of its role in drug metabolism in humans. Different liquid chromatography tandem mass spectrometry methodologies have been developed for the fast and routine analysis of major in vivo and in vitro CYPs enzyme activities. The high sensitivity and selectivity of mass spectrometry allow traditional assays to be minimized, thus saving time, efforts and money. Therefore this technology has become the method of choice for the fast assessment of CYP enzyme activities in early drug discovery development. Our intention herein is to review the most recent approaches that have been developed to quickly assess CYPs activities using in vitro models and liquid chromatography coupled with mass spectrometry, as well as their application in early drug discovery. PMID:18220567

  13. Liquid Chromatography-Tandem Mass Spectrometry Analysis of Perfluorooctane Sulfonate and Perfluorooctanoic Acid in Fish Fillet Samples

    PubMed Central

    Paiano, Viviana; Fattore, Elena; Carrà, Andrea; Generoso, Caterina; Fanelli, Roberto; Bagnati, Renzo

    2012-01-01

    Perfluorooctane sulfonate (PFOS) and perfluorooctanoic (PFOA) acid are persistent contaminants which can be found in environmental and biological samples. A new and fast analytical method is described here for the analysis of these compounds in the edible part of fish samples. The method uses a simple liquid extraction by sonication, followed by a direct determination using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The linearity of the instrumental response was good, with average regression coefficients of 0.9971 and 0.9979 for PFOS and PFOA, respectively, and the coefficients of variation (CV) of the method ranged from 8% to 20%. Limits of detection (LOD) were 0.04 ng/g for both the analytes and recoveries were 90% for PFOS and 76% for PFOA. The method was applied to samples of homogenized fillets of wild and farmed fish from the Mediterranean Sea. Most of the samples showed little or no contamination by perfluorooctane sulfonate and perfluorooctanoic acid, and the highest concentrations detected among the fish species analyzed were, respectively, 5.96 ng/g and 1.89 ng/g. The developed analytical methodology can be used as a tool to monitor and to assess human exposure to perfluorinated compounds through sea food consumption. PMID:22567564

  14. Simultaneous quantification of cardiovascular disease related metabolic risk factors using liquid chromatography tandem mass spectrometry in human serum.

    PubMed

    Wang, Mo; Yang, Ruiyue; Dong, Jun; Zhang, Tianjiao; Wang, Siming; Zhou, Weiyan; Li, Hongxia; Zhao, Haijian; Zhang, Lijiao; Wang, Shu; Zhang, Chuanbao; Chen, Wenxiang

    2016-01-15

    Recent observations from metabonomic studies have consistently found that branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), glutamine (Gln), glutamic acid (Glu), Gln/Glu ratio, carnitine, and several species of acylcarnitines and lysophosphatidylcholines (LPCs) are possible risk factors for metabolic diseases such as diabetes mellitus (DM) and cardiovascular diseases (CVD). We described here a simple and reliable method for simultaneous quantification of these metabolic risk factors by liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum samples were extracted with isopropanol, and the extracted metabolites were separated by hydrophilic interaction liquid chromatography (HILIC) and detected with electrospary ionization (ESI) inpositive ion mode with multiple reaction monitor (MRM) mode. All the metabolites were effectively separated within 5.5min. Analytical recoveries were in the range of 92.8-106.9%, with an average of 100.6%. The intra- run and total imprecisions for the measurement of these metabolites were 1.2-3.8% and 1.5-7.4%, respectively. Serum concentrations of the metabolites were analyzed in 123 apparently healthy volunteers. Significant associations between the metabolites and traditional CVD risk factors were observed. The newly developed LC-MS/MS method was simple, precise, and accurate and can be used as an efficient tool in CVD research and studies. PMID:26735710

  15. [Determination of common antibiotics and metronidazole in cosmetics by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Liu, Hualiang; Li, Fang; Yang, Run; Wang, Lianhong; Ma, Yongji

    2009-01-01

    A method for the analysis of common antibiotics and metronidazole in cosmetics was developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS). One gram of each cosmetic sample was extracted by methanol-water containing 0.1 mol/L formic acid (1:1, v/v). The extracted sample was filtered before being analyzed with UPLC/MS/MS. The effects of formic acid concentration in the mobile phase on the sensitivity and retention time were studied, and the results showed that 1% was the optimum concentration. Seven analytes, minocycline, oxytetracycline, tetracycline, chlortetracycline, doxycycline, chloramphenicol, metronidazole, can be separated and detected in 5 min, which is much faster than that by the conventional liquid chromatography. The detection limits were 3 - 20 ng/g, and the recoveries were 87% -101%. The calibration curves showed good linearity in the range of 2 - 1 000 microg/L with correlation coefficients larger than 0.995. The method was also applied to determine common antibiotics and metronidazole in 11 real samples from the market. Chloramphenicol was detected in 2 samples and the concentrations were 0.37% and 0.19%; metronidazole was detected in 1 sample and the concentration was 1.02%; others were not detected. PMID:19449540

  16. Determination of irinotecan and SN38 in human plasma by TurboFlow™ liquid chromatography-tandem mass spectrometry.

    PubMed

    Herviou, P; Richard, D; Roche, L; Pinguet, J; Libert, F; Eschalier, A; Durando, X; Authier, N

    2016-01-25

    Irinotecan is a cytotoxic agent used in the treatment of metastatic colorectal cancer. Irinotecan is a prodrug when is converted in vivo to an active metabolite SN38, which has potent pharmacological activity. SN38 is then inactivated and excreted as SN38-glucuronide. High-performance liquid chromatography-mass spectrometry is a widely used bioanalysis technique that can be coupled to the turbulent-flow extraction line to shorten preparation time. A technique was developed to quantify irinotecan and its metabolite by liquid chromatography-tandem mass spectrometry coupled with a turbulent-flow online extraction method. Assays were performed on 100 μL of plasma after protein precipitation. The supernatant is injected directly into the extraction column, transferred to the chromatographic column, and analyzed by tandem mass spectrometry. Linearity, reproducibility and repeatability of the method were validated on a concentration range of 25-2500 ng/mL for irinotecan and 5-500 ng/mL for SN38. For the low limit of quantification of irinotecan and SN38, precision is 6.31% and 8.73%, and accuracy is 84.0% and 91.8%, respectively. The SN38-glucuronide determination protocol included a hydrolyzation step. This method was successfully used to quantify irinotecan, SN38 and SN38-G in human plasma in a clinical trial. PMID:26580826

  17. Development and validation of a multiclass method for the analysis of antibiotic residues in eggs by liquid chromatography-tandem mass spectrometry.

    PubMed

    Jiménez, V; Rubies, A; Centrich, F; Companyó, R; Guiteras, J

    2011-03-18

    A multiclass method for the analysis of residues, in egg matrices, of 41 antimicrobial agents belonging to seven families (sulfonamides, diaminopyridine derivates, quinolones, tetracyclines, macrolides, penicillins and lincosamides) was developed and validated according to the requirements of European Commission Decision 2002/657. Compounds were extracted with a pressurized liquid extraction (PLE) technique using a 1:1 mixture of acetonitrile and a succinic acid buffer (pH 6.0) at 70 °C. As this resulted in clear extracts, no further clean-up was necessary. Analytes were determined by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPL-MS/MS) in a chromatographic run of 13 min. Calibration was carried out with spiked blank samples subjected to the entire analytical procedure. Five compounds, two of them isotopically labelled, were used as internal standards. Most analytes were quantified with errors below 10%. Precision in terms of reproducibility standard deviation was between 10% and 20% in most cases. CCα values were in the range 0.5-3.8 μg kg⁻¹ for the non-authorized compounds. The proposed method would enable an experienced analyst to process about 25 samples per day. PMID:21306719

  18. Quantitative analysis of delta9-tetrahydrocannabinol in preserved oral fluid by liquid chromatography-tandem mass spectrometry.

    PubMed

    Laloup, Marleen; Ramirez Fernandez, Maria del Mar; Wood, Michelle; De Boeck, Gert; Henquet, Cécile; Maes, Viviane; Samyn, Nele

    2005-07-29

    A rapid and sensitive method for the analysis of delta9-tetrahydrocannabinol (THC) in preserved oral fluid was developed and fully validated. Oral fluid was collected with the Intercept, a Food and Drug Administration (FDA) approved sampling device that is used on a large scale in the U.S. for workplace drug testing. The method comprised a simple liquid-liquid extraction with hexane, followed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis. Chromatographic separation was achieved using a XTerra MS C18 column, eluted isocratically with 1 mM ammonium formate-methanol (10:90, v/v). Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions. The use of the liquid-liquid extraction was demonstrated to be highly effective and led to significant decreases in the interferences present in the matrix. Validation of the method was performed using both 100 and 500 MicroL of oral fluid. The method was linear over the range investigated (0.5-100 ng/mL and 0. 1-10 ng/mL when 100 and 500 microL, respectively, of oral fluid were used) with an excellent intra-assay and inter-assay precision (relative standard deviations, RSD <6%) for quality control samples spiked at a concentration of 2.5 and 25 ng/mL and 0.5 and 2.5 ng/mL, respectively. Limits of quantification were 0.5 and 0.1 ng/mL when using 100 and 500 microL, respectively. In contrast to existing GC-MS methods, no extensive sample clean-up and time-consuming derivatisation steps were needed. The method was subsequently applied to Intercept samples collected at the roadside and collected during a controlled study with cannabis. PMID:16038190

  19. Liquid chromatography-tandem mass spectrometry to determine the stability of collagen pentapeptide (KTTKS) in rat skin.

    PubMed

    Park, Eun Ji; Kim, Myung Sun; Choi, Yun Lim; Shin, Young-Hee; Lee, Hye Suk; Na, Dong Hee

    2012-09-15

    The objective of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine the stability of collagen pentapeptide (KTTKS), which is a subfragment of collagen and has been proved to promote the extracellular release of collagen in skin fibroblast, in rat skin. The chromatographic condition was optimized on an Acclaim C-18 column (2.1 mm × 150 mm, 3 μm) under isocratic elution using a mobile phase consisting of deionized water and acetonitrile (87:13, v/v) mixture containing 5mM pentafluoropropionic acid as an ion-pairing reagent. The quantitation of KTTKS was performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode. The calibration curve showed good linearity in the concentration range of 0.05-10.0 μg/mL (r(2)>0.999). The intra- and inter-day precisions were 0.8-6.5% and 2.4-5.8%, respectively, and the intra- and inter-day accuracies were 96.3-102.7% and 92.8-98.5%, respectively. The developed LC-MS/MS method was successfully applied to investigate the degradation rate and sites of KTTKS in rat skin homogenate. KTTKS was found to be very susceptible to the peptide bond cleavage by aminopeptidases present in the skin. PMID:22921149

  20. [Determination of bisphenol A in plastic parts of small household appliances by liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Yan; Ma, Xiaofei; Lü, Pin; Li, Hui; Lu, Xiaoyu

    2012-01-01

    A method for the determination of bisphenol A in the plastic parts of small household appliances by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The sample was extracted with accelerated solvent extraction (ASE) and purified by Sep-Pak C18 solid phase extraction. Bisphenol A was separated and detected using LC-MS/MS in negative ion mode with the mobile phases of methanol and water (containing 0.05% ammonia water). The linearity of the method was good in the range of 5 μg/L to 100 μg/L. The recoveries for the spiked sample were from 95.2% to 109.7% at the three levels, 10, 25 and 75 μg/kg. The relative standard deviations were less than 3.8%. The limit of detection was 10 μg/kg. The method is easy-handling, time-saving, sensitive and suitable for the determination of the residual bisphenol A in the plastic parts of household appliances. PMID:22667100

  1. [Simultaneous determination of 11 bisphenols in plastic bottled drinking water by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Gou, Xinlei; Gao, Xia; Hu, Guanghui; Chi, Haitao; Le, Shengfeng; Wang, Wei; Liu, Weili

    2014-09-01

    A sensitive method was developed for the simultaneous determination of 11 bisphenols in plastic bottled drinking water by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were freeze-dried under vacuum and then dissolved with methanol. The separation was performed on a UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 μm) by using 0.1% (v/v) NH3 · H2O and methanol as mobile phases with gradient elution at a flow rate of 0.2 mL/min. The electrospray ionization (ESI) source in negative ion mode was used for the analysis of the 11 bisphenols in the multiple reaction monitoring (MRM) mode. The results verified that the standard curves for the 11 bisphenols were obtained with good correlation coefficients (R2) > 0.997 in their concentration ranges. The limits of detection (LOD, S/N = 3) for the 11 bisphenols were in the range of 0.01-1.00 μg/L. The mean recoveries for the 11 bisphenols at three spiked levels (low, middle, high) were 75.3%-102.1% with the relative standard deviations of 1.5%-8.9%. Seven plastic bottled drinking water samples were tested, and no bisphenol was found. The method is accurate, simple, rapid and feasible for the simultaneous determination of bisphenols in plastic bottled drinking water. PMID:25752093

  2. Liquid chromatography-tandem mass spectrometric assay for eltrombopag in 50μL of human plasma: a pharmacokinetic study.

    PubMed

    Maddela, Rambabu; Gajula, Ramakrishna; Pilli, Nageswara Rao; Siddiraju, Sridhar; Maddela, Srinubabu; Makula, Ajitha

    2014-09-01

    Eltrombopag is a thrombopoietin receptor agonist, used in the treatment of thrombocytopenia. This paper describes a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay method for the determination of eltrombopag in human plasma samples using eltrombopag 13C4 as internal standard (IS). Analyte and the IS were extracted from 50μL of human plasma using protein precipitation technique with no drying, evaporation and reconstitution steps. The chromatographic separation was achieved on a C18 column by using a mixture of 10mM ammonium formate (pH3) and acetonitrile (10:90, v/v) as the mobile phase at a flow rate of 1.0mL/min. The linearity of the method was established in the concentration range 50.0-10007ng/mL with r(2)≥0.99. The intra-day and inter-day precision and accuracy results in four validation batches across five concentration levels were well within the acceptance limits. The proposed method was found to be applicable to pharmacokinetic studies. PMID:24887483

  3. Quantification of Modified Tyrosines in Healthy and Diabetic Human Urine using Liquid Chromatography/Tandem Mass Spectrometry.

    PubMed

    Kato, Yoji; Dozaki, Natsuko; Nakamura, Toshiyuki; Kitamoto, Noritoshi; Yoshida, Akihiro; Naito, Michitaka; Kitamura, Masayasu; Osawa, Toshihiko

    2009-01-01

    The quantification of urinary oxidized tyrosines, dityrosine (DiY), nitrotyrosine (NY), bromotyrosine (BrY), and dibromotyrosine (DiBrY), was accomplished by quadruple liquid chromatography-tandem mass spectrometry (LC/MS/MS). The sample was partially purified by solid phase extraction, and was then applied to the LC/MS/MS using multiple-reaction monitoring (MRM) methods. The analysis for the DiY quantification was done first. The residual samples were further butylated with n-butanol/HCl, and the other modified tyrosines were then quantified with isotopic dilution methods. MRM peaks of the modified tyrosines (DiY, NY, BrY, and DiBrY) from human urine were measured and the elution times coincided with the authentic and isotopic standards. The amounts of modified tyrosines in healthy human urine (n = 23) were 8.8 +/- 0.6 (DiY), 1.4 +/- 0.4 (NY), 3.8 +/- 0.3 (BrY), and 0.7 +/- 0.1 (DiBrY) micromol/mol of creatinine, respectively. A comparison of the modified tyrosines with urinary 8-oxo-deoxyguanosine, pentosidine, and N(epsilon)-(hexanoyl)lysine was also performed. Almost all products, except for NY, showed good correlations with each other. The amounts of the modified tyrosines (NY, BrY, and DiBrY) in the diabetic urine were higher than those in the urine from healthy people. PMID:19177191

  4. Rapid test by liquid chromatography/tandem mass spectrometry to evaluate equine urine reactivity towards 17beta-OH steroids.

    PubMed

    Fidani, Marco; Casagni, Eleonora; Montana, Marco; Pasello, Emanuela; Pecoraro, Chiara; Gambaro, Veniero

    2006-01-01

    Bacteria frequently found in equine urine samples may cause degradation of 17beta-OH steroids. A simple liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed to evaluate the microbiological contamination of equine urine as a marker of poor storage conditions. Norethandrolone was used as the internal standard, and the linearity, sensitivity, precision and accuracy of the method were evaluated. 17beta-OH oxidation was demonstrated for testosterone, nandrolone, trenbolone and boldenone, but did not occur in alpha-epimers such as alpha-boldenone and epitestosterone, demonstrating the stereoselectivity of the reaction. A rapid test was performed by spiking one of the four 17beta-OH steroids in samples of diluted equine urine. The steroids were transformed into their respective ketones in the presence of bacterial activity. The test allows direct injection of diluted samples into the LC/MS system, without the need for prior extraction. Results show that the best method of storage is freezing at -18 degrees C. Urine specimens should be analyzed as soon as possible after thawing. This allows bacterial degradation of equine urine to be arrested temporarily, so that the urine can be used for qualitative or quantitative analysis of 17beta-OH steroids. PMID:16862626

  5. Accurate determination of ochratoxin A in Korean fermented soybean paste by isotope dilution-liquid chromatography tandem mass spectrometry.

    PubMed

    Ahn, Seonghee; Lee, Suyoung; Lee, Joonhee; Kim, Byungjoo

    2016-01-01

    Ochratoxin A (OTA), a naturally occurring mycotoxin, has been frequently detected in doenjang, a traditional fermented soybean paste, when it is fermented under improper conditions. Reliable screening of OTA in traditional fermented soybean paste (doenjang) is a special food-safety issue in Korea. Our laboratory, the National Metrology Institute of Korea, established an isotope dilution-liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method as a higher-order reference method to be used for SI-traceable value-assignment of OTA in certified reference materials (CRMs). (13)C20-OTA was used as an internal standard. Sample preparation conditions and LC/MS measurement parameters were optimised for this purpose. The analytical method was validated by measuring samples fortified with OTA at various levels. Repeatability and reproducibility studies showed that the ID-LC/MS/MS method is reliable and reproducible within 2% relative standard deviation. The analytical method was applied to determine OTA in various commercial doenjang products and home-made doenjang products. PMID:26212984

  6. [Simultaneous determination of 16 flavonoids in the ginkgo dietary supplement tea by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Jiang, Yalan; Huang, Fang; Wu, Fuhai; Wu, Huiqin; Huang, Xiaolan; Deng, Xin

    2015-10-01

    A method for the determination of 16 functional components of ginkgo dietary supplement tea such as catechin, vitexin, puerarin, isoflavoues aglycone, silymarin, quercetin, luteolin, apigenin, naringenin, hesperitin dihydrochalcone, kaempferol, hesperitin, isorhamnetin, baicalein, nobiletin and tangeretin by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was proposed. The conditions of chromatography and mass spectrometry were optimized. The 16 flavonoids were separated on a C18 chromatographic column with acetonitrile and water (additional 0.1% formic acid) as mobile phases under gradient elution at a flow rate of 0.25 mL/min. The determination was conducted by tandem mass spectrometry in positive ESI mode under multiple reaction monitoring (MRM) mode. Good linearities for all the compounds, with correlation coefficients over 0.996, were acquired. The recoveries were in the range of 70.9% to 100.0% (n = 6), while the relative standard deviations (RSDs) were less than 10%. The results showed that the nine flavonoids, which were kaempferol, quercetin, hesperitin, vitexin, luteolin, catechin, apigenin, naringenin and isorhamnetin, were higher in contents among the 16 flavonoids in real samples, and they constituted up to 99.6% of the total flavonoids. The contents of these nine flavonoids can be considered as the quality control index of the ginkgo dietary supplement tea. The method proved to be rapid, selective, sensitive and stable, and it can be applied to control the quality of the ginkgo dietary supplement tea. PMID:26930959

  7. Sensitive liquid chromatography/tandem mass spectrometry method for the simultaneous determination of nine local anesthetic drugs.

    PubMed

    Tonooka, Keiko; Naruki, Nobuhiko; Honma, Kou; Agei, Kohei; Okutsu, Mayumi; Hosono, Tetsuji; Kunisue, Yoko; Terada, Masaru; Tomobe, Koji; Shinozuka, Tatsuo

    2016-08-01

    A high-performance liquid chromatography-tandem mass spectrometry (LC/MS/MS) with electrospray ionization (ESI) procedure for the simultaneous determination of nine local anesthetic drugs (procaine, mepivacaine, lidocaine, ropivacaine, oxybuprocaine, tetracaine, bupivacaine, T-caine and dibucaine) in human serum is described. The chromatographic separation was performed on a Mightysil-RP-18 GP II column (2.0mm×150mm, particle size 5μm). The mobile phase consisted of 10mM acetic ammonium buffer (pH 5.4) and acetonitrile and was delivered at a flow rate of 0.20mL/min. The triple quadrupole mass spectrometer was operated in positive ion mode, and multiple reaction monitoring was used for drug quantification. Solid-phase extraction of the nine local anesthetic drugs added to the human serum was performed with an Oasis(®) HLB extraction cartridges column. The method was linear for the investigated drugs over the concentration range of 10-100ng/mL. The recoveries of these drugs were in the range of 81.4-144%. The standard deviation (SD) values for all analytes were <0.10 for both intraday and interday accuracy and precision. The selectivity, accuracy and precision of this method are satisfactory for clinical and forensic applications. The sensitive and selective method offers the opportunity for the simultaneous screening and quantification, for clinical and forensic purposes, of almost all local anesthetics available in Japan. PMID:26986505

  8. Determination of veterinary pharmaceuticals in poultry litter and soil by methanol extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Furtula, Vesna; Huang, Lee; Chambers, Patricia A

    2009-09-01

    Pharmaceuticals are emerging contaminants with potential risks to the environment and human health. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for determination of the antimicrobials virginiamycin, monensin, salinomycin, narasin and nicarbazin in poultry litter and soil. This method involves methanol extraction and clean-up of extracts through glass microfibre filters, introduction of the extracts and separation of compounds on a Zorbax Eclipse XDB C8 column, and compound detection in a Quattro Micro Micromass spectrometer. For litter samples, Method Detection Limits ranged from 0.1-0.6 microg Kg(-1), while Limits of Quantitation (LOQs) were 2, 1, 0.4, 1 and 2 microg Kg(-1) for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. For soil samples calculated LOQs were 2, 3, 1, 1, and 1 microg Kg(-1) for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. Application of the LC-MS-MS method for detection of veterinary pharmaceuticals in litter collected from commercial poultry farms showed that compounds were present at concentrations ranging from 10-11,000 microg Kg(-1). PMID:20183082

  9. Determination of eleven coccidiostats in animal feed by liquid chromatography-tandem mass spectrometry at cross contamination levels.

    PubMed

    Cronly, Mark; Behan, P; Foley, B; Malone, E; Shearan, P; Regan, L

    2011-08-26

    A confirmatory multi-residue method has been developed to allow for the detection, confirmation and quantification of eleven coccidiostats in animal feed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method can be used to determine halofuginone, robenidine, nicarbazin, diclazuril, decoquinate, semduramicin, lasalocid, monensin, salinomycin, narasin, maduramicin at levels relating to unavoidable carry over as stated in Regulation 2009/8/EC. Feed samples are extracted with water and acetonitrile with the addition of anhydrous magnesium sulphate and sodium chloride. The extract then undergoes a freezing out step before being diluted and injected onto the LC-MS/MS system. The LC-MS/MS system is run in MRM mode with both positive and negative electrospray ionisation and can confirm all eleven analytes in a run time of 19 min. The sensitivity of the method allows quantification and confirmation for all coccidiostats at a 0.5% carry over level. The method was validated over three days in accordance with of European legislation; Commission Decision 2002/657/EC. Validation criteria of accuracy, precision, decision limit (CCα), and detection capability (CCβ) along with measurement uncertainty are calculated for all analytes. The method was then successfully used to analyse a number of feed samples that contained various coccidiostat substances. PMID:21742113

  10. [Simultaneous determination of six components in hair dyes by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    You, Feiming

    2015-01-01

    A sensitive method was developed for the simultaneous determination of six components which included 4, 4'-diaminodiphenylamine sulfate hydrate and 2,4-diaminophenol sulfate, etc. in hair dyes by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After extracted by water through ultrasonic extraction, the samples were analyzed by UPLC-MS/MS. The separation was performed on a Waters BEH-C18 column (100 mmx 2.1 mm, 1.7 microm) with gradient elution of 10 mmol/L ammonium acetate and acetonitrile. The electrospray ionization (ESI) source in positive ion mode was used for the analysis of the six components in the multiple reaction monitoring (MRM) mode. The results showed good linear relationships with all the correlation coefficients (R2) more than 0.99. The limits of detection (LODs, S/N=3) for the six components were in the range of 0.26-4.6 mg/kg. The average recoveries of the six components in the spiked samples were in the range of 83.0%-92.2% with the relative standard deviations (RSDs, n=6) of 5.4%-11.2%. The precision, accuracy, mean recoveries and the matrix effects satisfied the requirements of cosmetic sample measurement. The proposed method has been applied to the determination of six dyes in actual samples. This method is simple, accurate and effective for the simultaneous determination of the six components in hair dyes. PMID:25958662

  11. Paclobutrazol Residue Determination in Potato and Soil Using Low Temperature Partition Extraction and Ultrahigh Performance Liquid Chromatography Tandem Mass Spectrometry.

    PubMed

    Liu, Hongcheng; Lin, Tao; Mao, Jia; Lu, Huan; Yang, Dongshun; Wang, Jiliang; Li, Qiwan

    2015-01-01

    A simple, accurate, and highly sensitive analytical method was developed for determining the paclobutrazol residue in potato and soil, the dynamics dissipation in soil. Extraction was carried out by low temperature partitioning and analyzed by ultrahigh performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). For a favor extraction yield, the parameters such as temperature and solvent were optimized. The result showed that sample would be easily frozen and separated using acetonitrile under -20°C for 10 min. The limit of detection (LOD) was 0.5 μg/kg, and the limit of quantification (LOQ) was 2 and 5 μg/kg for potato and soil, respectively. The influence of paclobutrazol residue in potato was evaluated. The possible contamination of paclobutrazol from surface can be rinsed by distilled water or peeled off, but the paclobutrazol in potato harvest comes mainly from absorption and transport, which could not be removed by peeling. The half-life of paclobutrazol in soil was 20.64 days, and the residue was below 0.22 mg/kg on 50th day after spraying. According to the risk assessment with Need Maximum Daily Intake (NEDI) and Acceptable Daily Intake (ADI), a Maximum Residue Limit (MRL) of paclobutrazol in potato was recommended as 1.0 mg/kg. PMID:26448896

  12. Rapid analysis of organic farming insecticides in soil and produce using ultra-performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Drozdzyński, Dariusz; Kowalska, Jolanta

    2009-08-01

    A new method for the analysis of three ecological insecticides, namely azadyrachtin, spinosad (sum of spinosyn A and spinosyn D) and rotenone, in produce and soil samples is presented. Investigated compounds are one of the most significant insecticides authorized for organic farming crop protection in many countries. Extraction of the pesticides from plant and soil matrices was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The method entailed a single extraction of the investigated compounds with acidified acetonitrile followed by a dispersive solid-phase extraction cleanup step prior to the final determination by reverse-phase ultra-performance liquid chromatography/tandem quadrupole mass spectrometry (UPLC-MS/MS). Validation studies were carried out on cabbage, tomato and soil samples. Recoveries of the spiked samples were in the range between 67% and 108%, depending on the matrix and the spiking level. Relative standard deviations for all matrix-compound combinations did not exceed 12%. The limits of quantification were < or = 0.01 mg kg(-1) in all cases, except for azadirachtin. The developed method was applied to the analysis of real samples originating from organic farming production. PMID:19579019

  13. [Determination of spinosyns A and D residues in food by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Jin; Yang, Lizhong; Lin, Liyi; Chen, Luping; Zhou, Yu; Xu, Dunming

    2011-07-01

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was established for the determination of spinosyns A and D residues in foodstuffs. The food samples were extracted with acetonitrile-water (50:50, v/v), and then purified by an HLB solid phase extraction (SPE) column. The analytes were determined by HPLC-MS/MS and quantified by external standard method. The mass spectrometric detection was operated with electrospray in positive ionization mode and the spinosyns A and D were identified in multiple reaction monitoring (MRM) mode. The linear range of the method was 1-20 microg/L, with the correlation coefficient (r2) of 0.999 9. No significant matrix effect was found for spiked samples. The recoveries of spinosyns A and D spiked in food were 76.2%-114.0% at the spiked levels of 1-10 microg/kg. The relative standard deviations (RSDs) were less than 10%. The limits of detection (LODs) and quantification (LOQs) were 0.2 microg/kg and 0.5 microg/kg for spinosyn A, 0.5 microg/kg and 1.0 microg/kg for spinosyn D, respectively. The proposed procedure was applied to the analysis of 969 real samples from Xiamen, Fujian Province (China), of which 15 positive samples were found. The results showed that the proposed method is sensitive and accurate for the determination of spinosyns A and D in foodstuffs. PMID:22097790

  14. Determination of rutin in rat plasma by ultra performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

    PubMed

    Chen, Mengchun; Zhang, Xiaoqian; Wang, Hao; Lin, Baoli; Wang, Shuanghu; Hu, Guoxin

    2015-04-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method for the determination of rutin in rat plasma was developed and validated. After addition of tolbutamide as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm particle size), using acetonitrile-0.1% formic acid as the mobile phase with gradient elution, delivered at a flow-rate of 0.4 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 610.91→302.98 and m/z 271.2→155.1 were used to quantify for rutin and tolbutamide, respectively. This assay method has been fully validated in terms of specificity, linearity, recovery and matrix effect, accuracy, precision and stability. Calibration curves were linear in the concentration ranges of 25-2000 ng/mL for rutin. Only 3 min was needed for an analytical run. This developed method was successfully used for determination of rutin in rat plasma for pharmacokinetic study. PMID:25030991

  15. Metabolomic investigation of cholestasis in a rat model using ultra-performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Aoki, Masayo; Konya, Yutaka; Takagaki, Takeshi; Umemura, Koji; Sogame, Yoshihisa; Katsumata, Takashi; Komuro, Setsuko

    2011-07-15

    Metabolomics follows the changes in concentrations of endogenous metabolites, which may reflect various disease states as well as systemic responses to environmental, therapeutic, or genetic interventions. In this study, we applied metabolomic approaches to monitor dynamic changes in plasma and urine metabolites, and compared these metabolite profiles in Eisai hyperbilirubinemic rats (EHBR, an animal model of cholestasis) with those in the parent strain of EHBR - Sprague-Dawley (SD) rats - in order to characterize cholestasis pathophysiologically. Ultra-performance liquid chromatography/tandem mass spectrometry-based analytical methods were used to assay metabolite levels. More than 250 metabolites were detected in both plasma and urine, and metabolite profiles of EHBR differed from those of SD rats. The levels of antioxidative and cytoprotective metabolites, taurine and hypotaurine, were markedly increased in urine of EHBR. The levels of many bile acids were also elevated in plasma and urine of EHBR, but the extent of elevation depended on the particular bile acid. The levels of cytoprotective ursodeoxycholic acid and its conjugates were markedly elevated, while that of cytotoxic chenodeoxycholic acid remained unchanged, suggesting the balance of bile acids had shifted resulting in decreased toxicity. In EHBR, reduced biliary excretion leads to increased systemic exposure to harmful compounds including some endogenous metabolites. Our metabolomic data suggest that mechanisms exist in EHBR that compensate for cholestasis-related damage. PMID:21638360

  16. A Novel and Rapid Method to Determine Doxycycline in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Krishna, A. Chaitanya; Sathiyaraj, M.; Saravanan, R. S.; Chelladurai, R.; Vignesh, R.

    2012-01-01

    A simple, rapid, specific and sensitive liquid chromatography tandem mass spectrometric method has been developed and validated for the determination of doxycycline from the human plasma. Doxycycline is extracted from human plasma by solid phase extraction. Demeclocycline was used as an internal standard. Detection was performed at transitions of 444.800→428.200 for doxycycline and 464.700→448.100 for demeclocycline using mass spectrometry. Chromatographic separation of analyte and internal standard were carried out using a reverse phase C18, column at 0.500 ml/min flow. The assay of doxycycline is linear over the range of 0.055-7.612 μg/ml, with a precision <14.83%, regression coefficient (r2)=0.9961 and the limit of quantification in plasma for doxycycline was 0.055 μg/ml. Mean extraction recovery obtained was 95.55%. Samples are stable at room temperature for 6 h, processed samples were stable at least for 30.20 h and also stable at three freeze-thaw cycles. The method has been used to perform pharmacokinetic and bioequivalence studies in human plasma. PMID:23798780

  17. Levels of enzyme activities in six lysosomal storage diseases in Japanese neonates determined by liquid chromatography-tandem mass spectrometry.

    PubMed

    Mashima, Ryuichi; Sakai, Eri; Kosuga, Motomichi; Okuyama, Torayuki

    2016-12-01

    Lysosomal storage disorders (LSDs) are caused by defective enzyme activities in lysosomes, characterized by the accumulation of glycolipids, oligosaccharides, mucopolysaccharides, sphingolipids, and other biological substances. Accumulating evidence has suggested that early detection of individuals with LSDs, followed by the immediate initiation of appropriate therapy during the presymptomatic period, usually results in better therapeutic outcomes. The activities of individual enzymes are measured using fluorescent substrates. However, the simultaneous determination of multiple enzyme activities has been awaited in neonatal screening of LSDs because the prevalence of individual LSDs is rare. In this study, the activities of six enzymes associated with LSDs were examined with 6-plex enzyme assay using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The accumulation of enzyme products was almost linear for 0-20 h at 37 °C. Dried blood spots (DBSs) provided by the Centers for Disease Control and Prevention (CDC) were used for quality control (QC). The intraday and interday coefficient of variance values were < 25%. The enzyme activities of healthy individuals were higher than those of LSD-confirmed individuals. These results suggest that the levels of enzyme activities of six LSDs in a Japanese population were comparable to those of a recent report [Elliott et al. Mol Genet Metab 118 (2016) 304-309], providing additional evidence that the 6-plex LSD enzyme assay is a reproducible analytical procedure for neonatal screening. PMID:27625992

  18. [Simultaneous determination of 19 quinolone residues in honey using high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Ding, Tao; Shen, Dongxu; Xu, Jinzhong; Wu, Bin; Chen, Huilan; Shen, Chongyu; Shen, Weijian; Zhao, Zengyun; Lian, Hongzhen

    2009-01-01

    A method for the simultaneous analysis of 19 quinolone residues, enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin, difloxacin, oxolinic acid, flumequine, sarafloxacin, sparfloxacin, danofloxacin, fleroxacin, marbofloxacin, enofloxacin, orbifloxacin, pipemidic acid, pefloxacin, lomefloxacin, cinofloxacin, and nalidixic acid in honey was developed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). In comparison of the three different extraction methods, i.e. acid solution coupled with cation-exchange solid-phase extraction cartridge (PCX), neutral buffer solution coupled with a reversed-phase extraction cartridge (HLB) and alkali solution coupled with a strong anion-exchange solid-phase extraction cartridge (PAX), the third method was finally used. The cartridge was then applied to accumulate and purify the target analytes from the sample matrices in one step. The HPLC separation was performed on a C18 column with a linear gradient elution program of methanol and 0.1% formic acid solution as the mobile phase. Selective reaction monitoring (SRM) was used for the selective detection of 19 quinolones. The linearity of all the 19 quinolones in the range from 1 microg/L to 100 microg/L had correlation coefficient greater than 0.991. In the detection of spiked samples, the detection limit of the method was 1.0 microg/kg for all the 19 quinolones, and the recoveries were 71% - 118% with the relative standard deviations of 4.2% - 6.7%. Internal standard calibration was used for the quantitative analysis. PMID:19449537

  19. Determination of irradiation histories of raw beef livers using liquid chromatography-tandem mass spectrometry of 5,6-dihydrothymidine.

    PubMed

    Fukui, Naoki; Takatori, Satoshi; Kitagawa, Yoko; Okihashi, Masahiro; Ishikawa, Etsuko; Fujiyama, Takatomo; Kajimura, Keiji; Furuta, Masakazu; Obana, Hirotaka

    2017-02-01

    A method for detecting irradiation histories of raw beef livers was developed by measuring 5,6-dihydrothymidine (DHdThd) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Liver DNA was extracted using phenol-chloroform extraction followed by precipitation in 50% ethanol. DNA was then enzymatically digested and nucleosides were purified using an OASIS MCX column. DHdThd and thymidine (dThd) contents of resulting test solutions were analyzed using LC-MS/MS. DHdThd was detected specifically after γ-irradiation. Concentration ratios of DHdThd to dThd in the test solutions increased dose-dependently after irradiation at 1.0-11.3kGy, which included the practical dose for sterilization of 2-7kGy. Dose-response curves from beef livers of individual animals almost overlapped. Thus, this method is a candidate for the detection of irradiation histories of foods from which DNA can be extracted. PMID:27596408

  20. A liquid chromatography-tandem mass spectrometry-based method for the simultaneous determination of hydroxy sterols and bile acids.

    PubMed

    John, Clara; Werner, Philipp; Worthmann, Anna; Wegner, Katrin; Tödter, Klaus; Scheja, Ludger; Rohn, Sascha; Heeren, Joerg; Fischer, Markus

    2014-12-01

    Recently, hydroxy sterols and bile acids have gained growing interest as they are important regulators of energy homoeostasis and inflammation. The high number of different hydroxy sterols and bile acid species requires powerful analytical tools to quantify these structurally and chemically similar analytes. Here, we introduce a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for rapid quantification of 34 sterols (hydroxy sterols, primary, secondary bile acids as well as their taurine and glycine conjugates). Chromatographic baseline separation of isomeric hydroxy sterols and bile acids is obtained using a rugged amide embedded C18 (polar embedded) stationary phase. The current method features a simple extraction protocol validated for blood plasma, urine, gall bladder, liver, feces, and adipose tissue avoiding solid phase extraction as well as derivatization procedures. The total extraction recovery for representative analytes ranged between 58-86% in plasma, 85% in urine, 79-92% in liver, 76-98% in adipose tissue, 93-104% in feces and 62-79% in gall bladder. The validation procedure demonstrated that the calibration curves were linear over the selected concentration ranges for 97% of the analytes, with calculated coefficients of determination (R2) of greater than 0.99. A feeding study in wild type mice with a standard chow and a cholesterol-enriched Western type diet illustrated that the protocol described here provides a powerful tool to simultaneously quantify cholesterol derivatives and bile acids in metabolically active tissues and to follow the enterohepatic circulation. PMID:25456597

  1. New insights in Adipokinetic Hormone (AKH) precursor processing in Locusta migratoria obtained by capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Baggerman, G; Huybrechts, J; Clynen, E; Hens, K; Harthoorn, L; Van der Horst, D; Poulos, C; De Loof, A; Schoofs, L

    2002-04-01

    After translation, the AKH I and AKH II precursors form three dimeric constructs prior to further processing into the respective AKHs and three dimeric Adipokinetic Hormone Precursor Related Peptides or APRPs (two homodimers and one heterodimer). By capillary liquid chromatography-tandem mass spectrometry we demonstrate that the APRPs in Locusta migratoria are further processed to form two smaller neuropeptides: DAADFADPYSFL (residue 36 to 47 of the AKH I precursor) and YADPNADPMAFL (residue 34 to 45 of the AKH II precursor). The peptides are designated as Adipokinetic Hormone Joining Peptide 1 (AKH-JP I) and 2 (AKH-JP II) respectively. Within the AKH I and AKH II precursor molecules, the classic KK and RR processing sites separate the AKH-JPs from the AKH I and II respectively. At the carboxyterminus, both AKH-JP I and II are flanked by Tyr-Arg, a cleaving site not described before. Such an unusual cleavage site suggests the presence, in the corpora cardiaca, of specific convertases. The AKH-JP-II does not stimulate lipid release from the fat body nor does it stimulate glycogen phosphorylase activity, both key functions of AKH. PMID:11897382

  2. Simultaneous determination of plant growth regulator and pesticides in bean sprouts by liquid chromatography-tandem mass spectrometry.

    PubMed

    Kim, Kwang-Gon; Park, Duck-Woong; Kang, Gyung-Ri; Kim, Tae-Sun; Yang, Yongshik; Moon, Su-Jin; Choi, Eun-Ah; Ha, Dong-Ryong; Kim, Eun-Sun; Cho, Bae-Sik

    2016-10-01

    A simple and sensitive analytical method based on QuEChERS approach using liquid chromatography tandem mass spectrometry was developed and validated for the determination of 6-benzylaminopurine, carbendazim and thiabendazole in bean sprouts. Sodium chloride and sodium acetate were used for salting-out step and magnesium sulfate for clean-up. The validation of optimized method was satisfactory with recoveries, between 89.5% and 103.2% for the three compounds, and relative standard deviation (RSD) values less than 3.3% at 20 and 40ng/g fortification levels (n=5). Limit of detection (LOD) and limit of quantification (LOQ) was 2.1-3.7ng/g and 6.3-11.1ng/g, respectively. Monitoring of 126 bean sprout samples collected from local markets was performed to verify the adaptability in real samples. No pesticides were detected but 6-benzylaminopurine was found in 3 samples at the level of 15-20ng/g. The optimized method should be applicable for monitoring of 6-benzylaminopurine, carbendazim and thiabendazole in bean sprouts in short time. PMID:27132845

  3. Determination of nonylphenol ethoxylate metabolites in vegetables and crops by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    She, Yongxin; Wang, Jing; Zheng, Yongquan; Cao, Weiqiang; Wang, Rongyan; Dong, Fengshou; Liu, Xingang; Qian, Mingrong; Zhang, Hu; Wu, Liqing

    2012-05-01

    A method has been developed for the simultaneous determination of the concentration of nonylphenol (4-NP), nonylphenol monoethoxylates (NP1EO) and nonylphenol diethoxylates (NP2EO) in vegetables and crops by liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS/MS). These target compounds were extracted from vegetable and crop samples with acetonitrile, and then the extracts were cleaned using solid phase extraction with graphitised carbon black tandem primary secondary amine (PSA) cartridges. The MS method enabled highly reliable identification by monitoring the corresponding ammonium adduct [M+NH4](+) in the positive mode for NP1EO and NP2EO, and the deprotonated molecule [M-H](-) in the negative mode for 4-NP. Recoveries for the spiked samples ranged from 65% to 118%. The limit of detection (LOD) of 4-NP, NP1EO and NP2EO was 3, 5 and 0.1μgkg(-1), respectively. This method would be useful for the quick and routine detection of the residues of 4-NP, NP1EO and NP2EO in vegetables and crops. PMID:26434323

  4. Pantothenic acid quantification by a stable isotope dilution assay based on liquid chromatography-tandem mass spectrometry.

    PubMed

    Rychlik, Michael

    2003-07-01

    A stable isotope dilution assay for the quantification of free and total pantothenic acid has been developed by using [13C3,15N]-pantothenic acid as the internal standard. The three-dimensional specificity of liquid chromatography-tandem mass spectrometry enabled unequivocal determination of the vitamin. Due to the very simple extraction and clean-up procedure, free pantothenic acid could be analysed within 2 h, which is much faster than by microbiological or gas chromatographic assays. For quantification of total pantothenic acid, the vitamin was liberated from its conjugates by an overnight incubation with pigeon liver pantetheinase and alkaline phosphatase. In analyses of corn flour, the intra-assay coefficient of variation was 8.5% (n = 5) and 15.3% (n = 4) for free and total pantothenic acid, respectively. When pantothenic acid was added to corn starch at a level of 6 mg kg(-1), a recovery of 97.5% was found. Application of the stable isotope dilution assay to whole egg powder, hazel nuts and corn revealed similar data compared to those listed in nutrition data bases, whereas the content in mushrooms and porcine liver determined by the newly developed assay appeared to be lower and that of cocoa higher than reported in the literature. PMID:12894818

  5. Simultaneous determination of ten underivatized biogenic amines in meat by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

    PubMed

    Sirocchi, Veronica; Caprioli, Giovanni; Ricciutelli, Massimo; Vittori, Sauro; Sagratini, Gianni

    2014-09-01

    Biogenic amines (BAs) are considered to be important indicators of freshness and quality in food. In this work, an analytical method for analyzing ten underivatized BAs in meat by performance liquid chromatography-tandem mass spectrometry has been developed. Comparison between ion trap and triple quadrupole as mass analyzers indicated that the latter provides greater sensitivity and selectivity. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.987-0.999, and the limits of detection and limits of quantification were in the range of 0.002-0.1 mg l(-1) and 0.008-0.5 mg l(-1), respectively. Once validated, the method was used to analyze the concentrations of BAs in 16 commercial meat samples, for evaluating the freshness of food through the study of BA indices, i.e. biogenic amine index (BAI) and the ratio spermidine/spermine (SPD/SPE). The results indicated that all the samples were fresh, with a BAI lower than 1.49 mg kg(-1) and a SPD/SPE ratio lower than 0.41 in each case. This methodology for testing the freshness of meat has potential for quality control applications along the entire production chain of meat products. PMID:25230178

  6. [Determination of environmental estrogens in cow feed and soil by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Li, Xue; Mu, Guangqing; Chen, Lijun; Jiang, Tiemin

    2013-09-01

    An analytical method was developed for the determination of the residues of five environmental estrogens, including estriol, estradiol, estrone, bisphenol A and diethylstilbestrol, in the cow feed and soil by solid phase extraction (SPE) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The important parameters which affect the determination efficiency such as the mobile phase, the condition of mass spectrometry and solid phase extraction column were optimized. The optimal determination conditions were as follows: the sample was extracted with acetonitrile at first, then cleaned-up with an NH2-SPE column, and an Acquity UPLC HSS T3 column was selected to separate the analytes. Acetonitrile-methanol (4: 1, v/v) and 0.01% ammonia aqueous solution were used as the mobile phase by gradient elution in the negative mode. The limits of detection (LOD, S/N = 3) were 0.06 - 0.22 microg/kg. The overall recoveries varied from 81.70% to 102.20%, and the relative standard deviations (RSDs) were all less than 10.00%. This method is simple, sensitive and accurate, and suitable for the determination of environmental estrogens in cow feed and soil. PMID:24392631

  7. Degradation and interconversion of plant pteridines during sample preparation and ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Van Daele, Jeroen; Blancquaert, Dieter; Kiekens, Filip; Van Der Straeten, Dominique; Lambert, Willy E; Stove, Christophe P

    2016-03-01

    The degradation and interconversion of a selected set of pterins (dihydroneopterin, hydroxymethyldihydropterin, dihydroxanthopterin, neopterin, hydroxymethylpterin, xanthopterin, 6-formylpterin, 6-carboxypterin and pterin), spiked to charcoal-treated potato and Arabidopsis thaliana matrix was investigated, together with their relative recovery in potato and A. thaliana. As a result, a matrix-specific procedure for the ultra-high performance liquid chromatography-tandem mass spectrometry based determination of 6 aromatic pterins (neopterin, hydroxymethylpterin, xanthopterin, 6-formylpterin, 6-carboxypterin and pterin) is proposed: 1.5ml of an N2-flushed, alkaline (pH=10) extraction solvent is added to 200mg of plant sample. After boiling and homogenization, the samples are incubated: Arabidopsis samples for 30min at room temperature, while shaking, and potato samples for 2h at 37°C (applying a dienzyme treatment with α-amylase and protease). After a final boiling step, the samples are ultrafiltrated and resulting extracts are analyzed by UHPLC-MS/MS. PMID:26471671

  8. Comprehensive screening of acidic and neutral drugs in equine plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    Yu, Nola H; Ho, Emmie N M; Tang, Francis P W; Wan, Terence S M; Wong, April S Y

    2008-05-01

    A multi-target high-throughput liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the detection of low ppt to low ppb levels of anabolic steroids, corticosteroids, anti-diabetics, and non-steroidal anti-inflammatory drugs (NSAIDs) in equine plasma was developed for the purpose of doping control. Plasma samples were first deproteinated by addition of trichloroacetic acid. Drugs were then extracted by solid-phase extraction (SPE) using Bond Elut Certify cartridges, and the extracts were analysed by a triple-quadrupole/linear ion trap LC-MS-MS instrument in positive electrospray ionization (+ESI) mode with selected reaction monitoring (SRM) scan function. Chromatographic separation of the targeted drugs was achieved using a reverse phase 3.3 cm L x 2.1 mm ID, 3 microm particle size LC column with gradient elution. Plasma samples fortified with 66 targeted drugs including betamethasone, boldione, capsaicin, flunisolide, gestrinone, gliclazide, 17alpha-hydroxyprogesterone hexanoate, isoflupredone and triamcinolone acetonide, etc. at low ppt to low ppb levels could be consistently detected. No significant matrix interference was observed at the retention time of the targeted ion transitions when blank plasma samples were analysed. The method has been validated for its extraction recoveries, precision and sensitivity, and is used regularly in the authors' laboratory to screen for the presence of these drugs in plasma samples from racehorses. PMID:18054785

  9. Determination of artificial sweeteners in beverages with green mobile phases and high temperature liquid chromatography-tandem mass spectrometry.

    PubMed

    Ordoñez, Edgar Y; Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2015-02-15

    A new analytical procedure involving the use of water and a low percentage of ethanol combined to high temperature liquid chromatography-tandem mass spectrometry has been developed for the determination of nine high-intensity sweeteners in a variety of drink samples. The method permitted the analysis in 23min (including column reequilibration) and consuming only 0.85mL of a green organic solvent (ethanol). This methodology provided limits of detection (after 50-fold dilution) in the 0.05-10mg/L range, with recoveries (obtained from five different types of beverages) being in the 86-110% range and relative standard deviation values lower than 12%. Finally, the method was applied to 25 different samples purchased in Spain, where acesulfame and sucralose were the most frequently detected analytes (>50% of the samples) and cyclamate was found over the legislation limit set by the European Union in a sample and at the regulation boundary in three others. PMID:25236212

  10. Determination of dexmedetomidine in children's plasma by ultra-performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

    PubMed

    Liu, Hua-Cheng; Sun, Wei; Wang, Cheng-Yu; Ying, Wei-Yang; Zheng, Li-Dan; Zeng, Rui-Feng; Wang, Zhe; Ge, Ren-Shan

    2016-06-15

    A rapid, sensitive, and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of dexmedetomidine in children's plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2mL of acetonitrile to a 0.1mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.1min and the elution of dexmedetomidine was at 1.24min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring mode using the respective transitions m/z 201.3→95.1 for dexmedetomidine and m/z 204.2→98.0 for the internal standard, respectively. The calibration curve was linear over the range of 0.05-10ng/mL with a lower limit of quantitation of 0.05ng/mL. Mean recovery rate of dexmedetomidine in plasma was in the range of 86.7-89.1%. Intra-day and inter-day precision were both <11.6%. This method was successfully applied in pharmacokinetic study after commencement of 1.0μg/kg dexmedetomidine infusion in children. PMID:27179189

  11. Determination of selected pharmaceutical compounds in biosolids by supported liquid extraction and gas chromatography-tandem mass spectrometry.

    PubMed

    Albero, Beatriz; Sánchez-Brunete, Consuelo; Miguel, Esther; Aznar, Ramón; Tadeo, José L

    2014-04-01

    In this work, an analytical method was developed for the determination of pharmaceutical drugs in biosolids. Samples were extracted with an acidic mixture of water and acetone (1:2, v/v) and supported liquid extraction was used for the clean-up of extracts, eluting with ethyl acetate:methanol (90:10, v/v). The compounds were determined by gas chromatography-tandem mass spectrometry using matrix-match calibration after silylation to form their t-butyldimethylsilyl derivatives. This method presents various advantages, such as a fairly simple operation for the analysis of complex matrices, the use of inexpensive glassware and low solvent volumes. Satisfactory mean recoveries were obtained with the developed method ranging from 70 to 120% with relative standard deviations (RSDs) ≤ 13%, and limits of detection between 0.5 and 3.6 ng g(-1). The method was then successfully applied to biosolids samples collected in Madrid and Catalonia (Spain). Eleven of the sixteen target compounds were detected in the studied samples, at levels up to 1.1 μg g(-1) (salicylic acid). Ibuprofen, caffeine, paracetamol and fenofibrate were detected in all of the samples analyzed. PMID:24582395

  12. Characterization of oncogene-induced metabolic alterations in hepatic cells by using ultrahigh performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Tang, Zhi; Cao, Tingting; Lin, Shuhai; Fu, Li; Li, Shangfu; Guan, Xin-Yuan; Cai, Zongwei

    2016-05-15

    Elucidation of altered metabolic pathways by using metabolomics may open new avenues for basic research on disease mechanisms and facilitate the development of novel therapeutic strategies. Here, we report the development of ultrahigh performance liquid chromatography-tandem mass spectrometry-based metabolomics platform with capability of measuring both cationic and anionic intermediates in cellular metabolism. The platform was established based on the hydrophobic ion-pairing interaction chromatography coupled with tandem mass spectrometry in multiple reaction monitoring (MRM) mode. The MRM transitions were created and optimized via energy-resolved collision-induced dissociation experiments, serving as an essential reference point for the quantification and identification. For chromatographic separation, application of hydrophobic ion-pairing interaction led to dramatic enhancement on retention of water-soluble metabolites and provision of good peak shapes. Two volatile ion-pairing reagents, namely heptafluorobutyric acid and tributylamine, were used with dedicated C18 columns as complementary separation systems coupled with the MRM analysis, allowing measurement of the metabolites of interest at nanomolar levels. The developed platform was successfully applied to investigate the altered metabolism in hepatic cells with over-expression of an oncogene, thus can provide important information on the rewired metabolism. PMID:26992502

  13. Quantification of horse plasma proteins altered by xylazine using the fluorogenic derivatization-liquid chromatography-tandem mass spectrometry

    PubMed Central

    MORI, Miwako; ICHIBANGASE, Tomoko; YAMASHITA, Shozo; KIJIMA-SUDA, Isao; KAWAHARA, Masahiro; IMAI, Kazuhiro

    2016-01-01

    ABSTRACT In the doping tests currently used in horse racing, prohibited substances or their metabolites are usually directly detected in urine or blood samples. However, despite their lasting pharmaceutical effects, some prohibited substances are rapidly eliminated from horse urine and blood, making them difficult to detect. Therefore, new indirect biomarkers for doping, such as plasma proteins that are increased by the prohibited substances, have recently attracted much attention. Here, a fluorogenic derivatization-liquid chromatography-tandem mass spectrometry (FD-LC-MS/MS) method was adopted for horse plasma proteomics analysis, in order to identify plasma proteins whose concentrations were altered in response to xylazine in Thoroughbred horses. Xylazine, which is rapidly absorbed and eliminated and has possibility of the change in the levels of plasma proteins, was selected as a model drug. Of the ten plasma proteins identified, four proteins, including three acute phase proteins (haptoglobin, ceruloplasmin, and α-2-macroglobulin-like), were significantly increased after xylazine administration. Therefore, our present approach might be useful in identifying indirect biomarkers of drug administration. PMID:26858580

  14. Simultaneous quantification of trantinterol and its metabolites in human urine by ultra performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Qin, Feng; Wang, Lijuan; Li, Kunjie; Xiong, Zhili; Li, Famei

    2015-08-01

    A rapid, selective and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to simultaneously determine trantinterol and its major metabolites in human urine. Waters Oasis HLB C18 solid phase extraction cartridges were used in the urine sample preparation. The separation was carried out on an ACQUITY UPLC™ BEH C18 column with methanol-0.2% formic acid (30:70, v/v) as the mobile phase at a flow rate of 0.25mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source. The linear calibration curves for trantinterol, arylhydroxylamine trantinterol (N-OH-trantinterol), the tert-butyl hydroxylated trantinterol (tert-OH-trantinterol) and the 1-carbonyl trantinterol (trantinterol-COOH) were obtained in the concentration range of 0.414-207, 0.578-385, 0.168-84.0, and 0.954-477ng/mL, respectively. The linear correlation coefficients were greater than 0.990. The intra and inter-day precision (relative standard deviation, RSD) values were less than 12% and the accuracy (relative error, RE) was 6.7-11%. The method herein described was superior to previous methods in sample throughput and sensitivity and successfully applied to the human excretion study. PMID:26093121

  15. Simultaneous Determination of Fucoxanthin and Its Deacetylated Metabolite Fucoxanthinol in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Zhang, Yiping; Wu, Hao; Wen, Hongmei; Fang, Hua; Hong, Zhuan; Yi, Ruizao; Liu, Rui

    2015-10-01

    Fucoxanthin and its deacetylated metabolite fucoxanthinol are two major carotenoids that have been confirmed to possess various pharmacological properties. In the present study, fucoxanthinol was identified as the deacetylated metabolite of fucoxanthin, after intravenous (i.v.) and intragastric gavage (i.g.) administration to rats at doses of 2 and 65 mg/kg, respectively, by liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Next, an accurate and precise LC-MS/MS method was developed to quantitatively determine fucoxanthin and fucoxanthinol in rat plasma. Plasma samples were resolved by LC-MS/MS on a reverse-phase SB-C18 column that was equilibrated and eluted with acetonitrile (A)/aqueous 0.1% formic acid (B; 92/8, v/v) at a flow rate of 0.5 mL/min. Analytes were monitored by multiple-reaction monitoring (MRM) under positive electrospray ionization mode. The precursor/product transitions (m/z) were 659.3→109.0 for fucoxanthin, 617.2→109.0 for fucoxanthinol, and 429.4→313.2 for the internal standard (IS). Calibration curves for fucoxanthin and fucoxanthinol were linear over concentrations ranging from 1.53 to 720 and 1.17 to 600 ng/mL, respectively. The inter- and intraday accuracy and precision were within ±15%. The method was applied successfully in a pharmacokinetic study and the resulting oral fucoxanthin bioavailability calculated. PMID:26512677

  16. Quantification of atrazine, phenylurea, and sulfonylurea herbicide metabolites in urine by high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Nguyen, Johnny V; Olsson, Anders O; Bravo, Roberto; Needham, Larry L; Barr, Dana B

    2007-05-01

    We developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method to measure metabolites of atrazine, phenylurea, and sulfonylurea herbicides in human urine. The metabolites measured in the method include atrazine mercapturate, desethyl atrazine, and desisopropyl atrazine as markers of atrazine exposure; dichlorophenyl urea, dichlorophenylmethyl urea, diuron, and linuron as markers of phenylurea herbicide exposure; and dimethoxypyrimidine, dimethylpyrimidine, and methoxymethyl triazine as markers for sulfonylurea herbicide exposure. The metabolites were extracted from urine by simple solid-phase extraction using a mixed-bed cartridge and were analyzed by HPLC-MS-MS. Quantification of the atrazine metabolites was achieved using isotope-dilution calibration. The remaining metabolites were quantified using similarly structured chemicals as internal standards. Extraction recoveries ranged from 88% to 104% (n = 5). Limits of detection for the entire method ranged from 0.125 to 1 ng/mL, and the average relative standard deviation of repeat measurements was about 13% (n = 30). PMID:17555640

  17. Simultaneous Determination of Hormonal Residues in Treated Waters Using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Guedes-Alonso, Rayco; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2013-01-01

    In the last years, hormone consumption has increased exponentially. Because of that, hormone compounds are considered emerging pollutants since several studies have determinted their presence in water influents and effluents of wastewater treatment plants (WWTPs). In this study, a quantitative method for the simultaneous determination of oestrogens (estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and diethylstilbestrol), androgens (testosterone), and progestogens (norgestrel and megestrol acetate) has been developed to determine these compounds in wastewater samples. Due to the very low concentrations of target compounds in the environment, a solid phase extraction procedure has been optimized and developed to extract and preconcentrate the analytes. Determination and quantification were performed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The method developed presents satisfactory limits of detection (between 0.15 and 9.35 ng·L−1), good recoveries (between 73 and 90% for the most of compounds), and low relative standard deviations (under 8.4%). Samples from influents and effluents of two wastewater treatment plants of Gran Canaria (Spain) were analyzed using the proposed method, finding several hormones with concentrations ranged from 5 to 300 ng·L−1. PMID:23533966

  18. Simultaneous determination of levophencynonate and its metabolite demethyl levophencynonate in human plasma by liquid chromatography tandem mass spectrometry.

    PubMed

    Li, Bo; Qi, Wenyuan; Shi, Aixin; Hu, Xin; Cheng, Gang

    2016-08-01

    A sensitive and convenient high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to determine levophencynonate and demethyl levophencynonate levels in human plasma simultaneously. Chromatographic separation was achieved on a SHIMADZU Shim-Pack XR C8 column and mass spectrometric analysis was performed by an API5000 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 358.4→156.4 and 344.5→144.2 were used to quantify levophencynonate and demethyl levophencynonate, respectively. This analytical method was fully validated with specificity, linearity, lower limit of quantitation (LLOQ), accuracy, precision, stability, matrix effect and recovery. The linearity of this method were developed to be within the concentration ranges of 10-4000pg/mL for levophencynonate and 25-8000pg/mL for demethyl levophencynonate in human plasma. This method was used in a clinical study which was administrated with single oral dose for Chinese healthy subjects to investigate the pharmacokinetics of levophencynonate and demethyl levophencynonate. PMID:27304783

  19. Determination of ochratoxin a in ready-to-drink coffee by immunoaffinity cleanup and liquid chromatography-tandem mass spectrometry.

    PubMed

    Noba, Shigekuni; Uyama, Atsuo; Mochizuki, Naoki

    2009-07-22

    We developed a simple and accurate method for determining ochratoxin A (OTA) in ready-to-drink coffee, using an immunoaffinity column for cleanup and liquid chromatography-tandem mass spectrometry (LC/MS/MS) for identification and quantification. When uniformly stable isotope-labeled OTA (U-[(13)C(20)]-OTA) was employed as an internal standard, the recovery rate of the method was 97.3% (the spiked OTA level was 0.10 ng/mL), the repeatability (relative standard deviation) was 1.9%, and the intermediate precision (relative standard deviation) was 4.0%. The limit of quantification was 0.0065 ng/mL based on a signal-to-noise ratio in coffee of 10:1. The developed method was used for the determination of OTA in ready-to-drink coffee. A total of 30 ready-to-drink coffee samples commercially available in Japan were analyzed. OTA was detected in all of the samples at concentrations ranging from trace levels (0.0020-0.010 ng/mL) to 0.037 ng/mL. This method was shown to be useful for accurately evaluating the intake of OTA from coffee beverages. PMID:19537783

  20. Characterization of botulinum neurotoxin type A subtypes by immunocapture enrichment and liquid chromatography-tandem mass spectrometry.

    PubMed

    Morineaux, Valérie; Mazuet, Christelle; Hilaire, Didier; Enche, Julien; Popoff, Michel R

    2015-07-01

    Botulinum neurotoxins (BoNT) are divided into seven toxinotypes based on their immunological properties and each toxinotype contains several subtypes according to their amino acid sequences. Here, we designed a mass spectrometry method able to identify BoNT/A subtypes in complex matrices including crude culture supernatants, food, and environmental samples. Peptides from BoNT light chain (L) specific to the subtypes BoNT/A1 to A3 and BoNT/A5 to A8 were identified. The method consists of an immunocapture step with antibodies specific to BoNT/A L chains followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on a triple quadrupole mass spectrometer (QqQ) in multiple reaction monitoring (MRM) mode. BoNT/A subtypes were correctly identified in culture supernatants and in tap water or orange juice samples with a limit of detection of 20 to 150 mouse lethal doses (MLD) and with a lower sensitivity in serum samples. PMID:26038189

  1. Determination of six sulfonamide antibiotics, two metabolites and trimethoprim in wastewater by isotope dilution liquid chromatography/tandem mass spectrometry.

    PubMed

    Le-Minh, Nhat; Stuetz, Richard M; Khan, Stuart J

    2012-01-30

    A highly sensitive method for the analysis of six sulfonamide antibiotics (sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine and sulfamethoxazole), two sulfonamide metabolites (N(4)-acetyl sulfamethazine and N(4)-acetyl sulfamethoxazole) and the commonly co-applied antibiotic trimethoprim was developed for the analysis of complex wastewater samples. The method involves solid phase extraction of filtered wastewater samples followed by liquid chromatography-tandem mass spectral detection. Method detection limits were shown to be matrix-dependent but ranged between 0.2 and 0.4 ng/mL for ultrapure water, 0.4 and 0.7 ng/mL for tap water, 1.4 and 5.9 ng/mL for a laboratory-scale membrane bioreactor (MBR) mixed liquor, 0.7 and 1.7 ng/mL for biologically treated effluent and 0.5 and 1.5 ng/g dry weight for MBR activated sludge. An investigation of analytical matrix effects was undertaken, demonstrating the significant and largely unpredictable nature of signal suppression observed for variably complex matrices compared to an ultrapure water matrix. The results demonstrate the importance of accounting for such matrix effects for accurate quantitation, as done in the presented method by isotope dilution. Comprehensive validation of calibration linearity, reproducibility, extraction recovery, limits of detection and quantification are also presented. Finally, wastewater samples from a variety of treatment stages in a full-scale wastewater treatment plant were analysed to illustrate the effectiveness of the method. PMID:22284510

  2. Simultaneous Determination of Fucoxanthin and Its Deacetylated Metabolite Fucoxanthinol in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Zhang, Yiping; Wu, Hao; Wen, Hongmei; Fang, Hua; Hong, Zhuan; Yi, Ruizao; Liu, Rui

    2015-01-01

    Fucoxanthin and its deacetylated metabolite fucoxanthinol are two major carotenoids that have been confirmed to possess various pharmacological properties. In the present study, fucoxanthinol was identified as the deacetylated metabolite of fucoxanthin, after intravenous (i.v.) and intragastric gavage (i.g.) administration to rats at doses of 2 and 65 mg/kg, respectively, by liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Next, an accurate and precise LC-MS/MS method was developed to quantitatively determine fucoxanthin and fucoxanthinol in rat plasma. Plasma samples were resolved by LC-MS/MS on a reverse-phase SB-C18 column that was equilibrated and eluted with acetonitrile (A)/aqueous 0.1% formic acid (B; 92/8, v/v) at a flow rate of 0.5 mL/min. Analytes were monitored by multiple-reaction monitoring (MRM) under positive electrospray ionization mode. The precursor/product transitions (m/z) were 659.3→109.0 for fucoxanthin, 617.2→109.0 for fucoxanthinol, and 429.4→313.2 for the internal standard (IS). Calibration curves for fucoxanthin and fucoxanthinol were linear over concentrations ranging from 1.53 to 720 and 1.17 to 600 ng/mL, respectively. The inter- and intraday accuracy and precision were within ±15%. The method was applied successfully in a pharmacokinetic study and the resulting oral fucoxanthin bioavailability calculated. PMID:26512677

  3. Determination of neonicotinoid insecticides and their metabolites in honey bee and honey by liquid chromatography tandem mass spectrometry.

    PubMed

    Gbylik-Sikorska, Malgorzata; Sniegocki, Tomasz; Posyniak, Andrzej

    2015-05-15

    The original analytical method for the simultaneous determination and confirmation of neonicotinoids insecticides (imidacloprid, clothianidin, acetamiprid, thiametoxam, thiacloprid, nitenpyram, dinotefuran) and some of their metabolites (imidacloprid guanidine, imidacloprid olefin, imidacloprid urea, desnitro-imidacloprid hydrochloride, thiacloprid-amid and acetamiprid-N-desmethyl) in honey bee and honey was developed. Preparation of honey bee samples involves the extraction with mixture of acetonitrile and ethyl acetate followed by cleaned up using the Sep-Pak Alumina N Plus Long cartridges. Honey samples were dissolved in 1% mixture of acetonitrile and ethyl acetate with addition of TEA, then extracts were cleaned up with Strata X-CW cartridges. The identity of analytes was confirmed using liquid chromatography tandem mass spectrometry. All compounds were separated on a Luna C18 column with gradient elution. The whole procedure was validated according to the requirements of SANCO 12571/2013. The average recoveries of the analytes ranged from 85.3% to 112.0%, repeatabilities were in the range of 2.8-11.2%, within-laboratory reproducibility was in the range of 3.3-14.6%, the limits of quantitation were in the range of 0.1-0.5μgkg(-1), depending of analyte and matrices. The validated method was successfully applied for the determination of clothianidin, imidacloprid and imidacloprid urea in real incurred honey bee samples and clothianidin in honey. PMID:25864015

  4. Quantification of nardosinone in rat plasma using liquid chromatography-tandem mass spectrometry and its pharmacokinetics application.

    PubMed

    Lu, Zhihe; Zhou, Peng; Zhan, Yuzhu; Su, Jingrong; Yi, Deliang

    2015-01-01

    A rapid, sensitive and high-throughput liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was established and validated to assay the concentration of nardosinone, a main active compound isolated from Nardostachys chinensis, in rat plasma. Plasma samples were processed by protein precipitation with acetonitrile and separated on a Venusil MP-C18 column (50 × 2.1 mm, 5 µm) at an isocratic flow rate of 0.6 mL/min using methanol-0.1% formic acid in water (55 : 45, v/v) as mobile phase, and total run time was 2.5 min. MS-MS detection was accomplished in selected reaction monitoring mode with positive electrospray ionization. The calibration curve was linear over the concentration range of 9.60-320 ng/mL with lower limit of quantification of 9.60 ng/mL. The intra- and inter-day precisions were below 12.3% in terms of relative standard deviation, and the accuracy was within ±9.0% in terms of relative error. Extraction recovery, matrix effect and stability were also satisfactory in rat plasma. The developed method was successfully applied to a pharmacokinetic study of nardosinone following an intravenous injection at a dose of 1.04 mg/kg to Sprague-Dawley rats. PMID:26116832

  5. Folate Profiling in Potato (Solanum tuberosum) Tubers by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Van Daele, Jeroen; Blancquaert, Dieter; Kiekens, Filip; Van Der Straeten, Dominique; Lambert, Willy E; Stove, Christophe P

    2014-03-31

    An ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the profiling of six folate species in potatoes. The calibration curves cover a wide, linear range (the lower and upper limits of quantitation range between 0.22-0.24 and 216.07-242.28 μg/100 g of fresh weight), allowing sensitive determination in small amounts of potato flesh. With a single exception, the acceptance criteria for intra- and interday precision and accuracy were met: for all quality controls, the percent relative standard deviation and the percent bias were lower than 15% (or 20% at the lower limit of quantitation). Application of the method on tubers at different stages of maturation demonstrated the large variability within a single variety: the folate content and polyglutamylation rate varied between 10.35 and 24.01 μg/100 g of fresh weight and between 4.96% and 60.49%, respectively. Additionally, the two-dimensional folate profiling of mature tubers demonstrated an increase in folate from center to peel, combined with a stable species distribution and polyglutamylation rate. PMID:24655154

  6. Quantitative determination of 12-hydroxyeicosatetraenoic acids by chiral liquid chromatography tandem mass spectrometry in a murine atopic dermatitis model

    PubMed Central

    Hong, Seong-Ho; Han, Ji Eun; Ko, Ji-Seung; Do, Sun Hee

    2015-01-01

    Atopic dermatitis, one of the most important skin diseases, is characterized by both skin barrier impairment and immunological abnormalities. Although several studies have demonstrated the significant relationship between atopic dermatitis and immunological abnormalities, the role of hydroxyeicosatetraenoic acids (HETE) in atopic dermatitis remains unknown. To develop chiral methods for characterization of 12-HETE enantiomers in a 1-chloro-2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model and evaluate the effects of 12-HETE on atopic dermatitis, BALB/c mice were treated with either DNCB or acetone/olive oil (AOO) to induce atopic dermatitis, after which 12(R)- and 12(S)-HETEs in the plasma, skin, spleen, and lymph nodes were quantified by chiral liquid chromatography-tandem mass spectrometry. 12(R)- and 12(S)-HETEs in biological samples of DNCB-induced atopic dermatitis mice increased significantly compared with the AOO group, reflecting the involvement of 12(R)- and 12(S)-HETEs in atopic dermatitis. These findings indicate that 12(R)- and 12(S)-HETEs could be a useful guide for understanding the pathogenesis of atopic dermatitis. PMID:25797298

  7. Immunoaffinity chromatography purification and ultrahigh performance liquid chromatography tandem mass spectrometry determination of tetrodotoxin in marine organisms.

    PubMed

    Zhang, Xiaojun; Yan, Zhongyong; Wang, Ying; Jiang, Tao; Wang, Jian; Sun, Xiumei; Guo, Yuanming

    2015-04-01

    A highly selective and sensitive method was developed for the determination of tetrodotoxin (TTX) in marine organisms by immunoaffinity chromatography (IAC) purification coupled with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). An IAC column was prepared and used to cleanup the extracted samples. The operating conditions of the IAC column were optimized, and the capacity of new IAC column was found to be 1106 ng mL(-1), which was sufficient for TTX determination. The MS/MS conditions and UPLC mobile phase were also studied to optimize the operation conditions. Fortified marine organism samples at levels of 0.3-5.0 ng g(-1) were utilized, and the average recoveries were 86.5-103.6% with intra- and inter-day relative standard deviations less than 7.22 and 9.88%, respectively. The limits of detection and quantification were 0.1 and 0.3 ng g(-1), respectively. The method was later successfully applied for the determination of TTX in 100 marine organism samples collected from local markets. PMID:25756833

  8. Derivatization of the tricarboxylic acid intermediates with O-benzylhydroxylamine for liquid chromatography-tandem mass spectrometry detection.

    PubMed

    Tan, Bo; Lu, Zhaohai; Dong, Sucai; Zhao, Genshi; Kuo, Ming-Shang

    2014-11-15

    The tricarboxylic acid (TCA) cycle is an interface among glycolysis, lipid metabolism, and amino acid metabolism. Increasing interest in cancer metabolism has created a demand for rapid and sensitive methods for quantifying the TCA cycle intermediates and related organic acids. We have developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify the TCA cycle intermediates in a 96-well format after O-benzylhydroxylamine (O-BHA) derivatization under aqueous conditions. This method was validated for quantitation of all common TCA cycle intermediates with good sensitivity, including α-ketoglutarate, malate, fumarate, succinate, 2-hydroxyglutarate, citrate, oxaloacetate, pyruvate, isocitrate, and lactate using a 8-min run time in cancer cells and tissues. The method was used to detect and quantify changes in metabolite levels in cancer cells and tumor tissues treated with a pharmacological inhibitor of nicotinamide phosphoribosyl transferase (NAMPT). This method is rapid, sensitive, and reproducible, and it can be used to assess metabolic changes in cancer cells and tumor samples. PMID:25102203

  9. [Simultaneous determination of three sulfonamide residues in modified milk by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Cheng, Guodong; Wu, Xiaohui; Jin, Zhu; Zhang, Yu; Hao, Dan; Tong, Mianhuan; Gao, Jianjun

    2015-08-01

    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method for the residue determination of sulfadiazine, sulfamerazine and sulfamethazine in modified milk was established. The modified milk samples were extracted and their protein precipitated with water (containing 1% (v/v) acetic acid) and methanol. Then they were purified with an HLB solid phase extraction cartridge. The separation was performed on an ACQUITY UPLC HSS T3 column (100 mm x 2.1 mm, 1.8 µm) with a gradient system of water (containing 0.1% (v/v) formic acid) and acetonitrile as mobile phases at a flow rate of 0.3 mL/min, and detected by the MS in ESI+ mode. Standard curves were drawn by using matrix standard addition method, and the external standard method was used for quantitative analysis. The limits of quantification were 1 µg/kg. The calibration curves for the three sulfa drugs were linear in the mass concentration range of 1-100 µg/L with R2 ≥ 0.998. The recoveries at the levels of 1, 2, 10 µg/kg fortified samples ranged from 76.5% to 101.9% with the relative standard deviations of 1.2%-12.4%. The method is simple, rapid, accurate, and its performance can meet the requirements of the domestic and international legislations. It is suitable for the detection of sulfonamide residues in modified milk. PMID:26749868

  10. A robust analytical method for measurement of phytoestrogens and related metabolites in serum with liquid chromatography tandem mass spectrometry.

    PubMed

    Jiang, Hongmei; Liao, Xiangjun; Wood, Carla M; Xiao, Chao-Wu; Feng, Yong-Lai

    2016-02-15

    A sensitive and robust method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for quantitation of 13 phytoestrogens and related metabolites in rat serum samples. A new type of column, the Kinetex core-shell C18 column, was applied for rapid separation of the target analytes in 10min. Two enzymes, sulfatase H-1 and gulcuronidase H-5 from Helix pomatia were compared on the efficiency of releasing the conjugated forms of the target analytes to their free forms in serum samples. The method detection limit (MDL) defined as three times the signal to noise ratio in spiked serum matrix-based solutions was in the range of 0.1-3.5ng/mL. The linear dynamic calibration was in the broad range of 0.2-500ng/mL for all target compounds. Thirty-two rat serum samples from the rats that were fed with diets containing either casein or soy protein isolates with various amounts of isoflavones for 8 weeks were analyzed for the target analytes with the developed method. Nine target analytes were detected in the serum samples. Those detectable compounds are all the metabolites of the dietary isoflavones, suggesting that the diet isoflavones were mostly metabolized to their metabolites in rat. PMID:26815920

  11. High Throughput Liquid Chromatography-Tandem Mass Spectrometry Assay for Mercapturic Acids of Acrolein and Crotonaldehyde in Cigarette Smokers’ Urine

    PubMed Central

    Carmella, Steven G.; Chen, Menglan; Zarth, Adam; Hecht, Stephen S.

    2014-01-01

    3-Hydroxypropylmercapturic acid (3-HPMA) and 3-hydroxy-1-methylpropylmercapturic acid (HMPMA) are urinary metabolites of the toxicants acrolein and crotonaldehyde, respectively. Virtually all human urine samples contain these metabolites, resulting from the action of glutathione-S-transferases on acrolein and crotonaldehyde, which are lipid peroxidation products, environmental and dietary contaminants, and constituents of cigarette smoke. We have developed a high throughput liquid chromatography-tandem mass spectrometry method for quantitative analysis of 3-HPMA and HMPMA in large numbers of small urine samples, as would be required in molecular epidemiology and clinical studies relating levels of these metabolites to cancer risk. Solid-phase extraction on mixed mode reverse phase-anion exchange 96-well plates provided sufficient purification for LC-MS/MS analysis, which was performed by auto-injection using a 96-well format, and resulted in clean, readily interpretable chromatograms, with detection limits of 4.5 pmol/mL urine for 3-HPMA and 3.5 pmol/mL urine for HMPMA. Accuracy was 92% for 3-HPMA and 97% for HMPMA while inter-day precision was 9.1% (coefficient of variation) for 3-HPMA and 11.0% for HMPMA. The method was applied to more than 2600 urine samples from smokers; mean levels of 3-HPMA and HMPMA were 4800 ± 5358 (S.D.) pmol/ml and 3302 ± 3341 pmol/ml, respectively. PMID:23934173

  12. Quantitative subcellular study of doxorubicin in MCF-7/Adr cells using liquid chromatography-tandem mass spectrometry.

    PubMed

    Ma, Wenzhuan; Wang, Jinling; Guo, Qiang; Tu, Pengfei

    2015-12-15

    A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the determination of doxorubicin in intracellular compartments using glibenclamide as internal standard (IS). MCF-7/Adr cancer cells (1×10(6)) were incubated with doxorubicin (8μg/mL) for 0.5, 1, 2 and 4h and then subjected to sequential extraction of cytosolic, membrane/organelle, nuclear and cytoskeleton soluble protein. Samples were extracted using protein precipitation with methanol. Chromatographic separation was carried out on a C18 column with acetonitrile and 0.1% formic acid water as mobile phase and with gradient elution at a flow rate of 0.2mL/min. The method was linear over the range of 1-300ng/mL with a lower limit of quantification (LLOQ) of 1ng/mL. The distribution of doxorubicin in subcellular components of MCF-7/Adr cancer cells was mainly in nucleic protein fraction. PMID:26562803

  13. Large-scale profiling of diterpenoid glycosides from Stevia rebaudiana using ultrahigh performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Shafii, Behnaz; Vismeh, Ramin; Beaudry, Randy; Warner, Ryan; Jones, A Daniel

    2012-07-01

    The plant Stevia rebaudiana accumulates a suite of diterpenoid metabolites that are natural sweeteners finding increased use as sugar substitutes. To guide breeding of stevia plants that accumulate substances with desirable flavor in high yield, rapid and accurate methods are needed to profile these substances in plant populations. This report describes an 8-min ultrahigh performance liquid chromatography-tandem mass spectrometry method for separation and quantification of seven stevia glycosides including steviolbioside; stevioside; rebaudiosides A, B, and C; rubusoside; and dulcoside as well as aglycones steviol and isosteviol. This negative mode electrospray ionization/multiple reaction monitoring method yielded low limits of detection <1 ng/mL for steviol, 6 ng/mL for isosteviol, and <15 ng/mL for all stevia glycosides. Stevioside and Reb A, B, and C were quantified in more than 1,100 extracts from stevia leaves as part of a large-scale profiling exercise. Leaf tissue levels in this population spanned about two orders of magnitude for stevioside (2-125 mg/g dry weight), Reb A (2.5-164 mg/g), Reb B (0.5-50 mg/g), and Reb C (1.5-125 mg/g), but levels of individual metabolites exhibited independent variation. The wide spread of metabolite levels highlights the utility and importance of performing targeted metabolic profiling for large plant populations. PMID:22580424

  14. [Determination of ten sedative residues in pork and kidney by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Sun, Lei; Zhang, Li; Xu, Qian; Wang, Shuhuai; Wang, Xia

    2010-01-01

    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the determination of methaqualone, chloropromazine, promethazine, diazepam, nitrazepam, oxazepam, temazepam, midazolam, triazolam and zolpidem residues in pork and kidney. After enzymolysis, the samples were extracted by ethyl acetate and tert-butyl methyl ether, separately. The separation of the ten sedatives was performed on a Waters Acquity UPLC system with a BEH C18 column. The mobile phases were acetonitrile (containing 0.1% formic acid) and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The electrospray was operated in the positive ionization mode and the ten sedatives were identified by multiple reaction monitoring (MRM) mode. The method of matrix-matched standard solution was adopted as the quantitative method. The calibration curves showed good linearity within the concentrations of 2 - 100 microg/L with the correlation coefficients r > 0. 998. The limits of detection of the ten sedatives were 0.5 microg/kg, and the limit of quantification was 1 microg/kg. The recoveries of the ten sedatives were 64.5% - 111.4% at the spiked levels of 2, 5 and 10 microg/kg. The relative standard deviations of intra- and inter-day coefficients of variation were both less than 15%. This method is simple, sensitive and accurate in the determination of sedative residues. PMID:20458918

  15. Determination of platycodin D and platycodin D3 in rat plasma using liquid chromatography-tandem mass spectrometry.

    PubMed

    Kim, Tae-Hyun; Lee, Byung Eui; Kim, Eun Joo; Choi, Yong Seok; Lee, Keun-Sung; Kim, Hak Rim; Kim, Hyung-Gun

    2014-01-01

    Platycodon grandiflorum has long been used as a traditional oriental medicine for respiratory disorder. Platycodin D (PD) is known as the main component isolated from the root of PG. A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitation of PD in rat plasma. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization and multiple reaction monitoring in positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of PD were linear over the concentration range of 50-10,000 ng/mL in rat plasma. The coefficient of variation and relative error at five QC levels were 1.0 to 8.8% and 0.7 to 8.7%, respectively. After a single oral administration of 500 mg/kg and a single intravenous administration of 25 mg/kg of 3% PD extract (a PG extract including 3% of PD), platycodin D and platycodin D3 were detected and pharmacokinetic parameters were estimated. The oral bioavailability of platycodin D and platycodin D3 was 0.29% and 1.35% in rats at 500 mg/kg of 3% PD extract of PG, respectively. The present method can be applied to pharmacokinetic analysis of platycodins and platycosides of the PG. PMID:24592150

  16. Paclobutrazol Residue Determination in Potato and Soil Using Low Temperature Partition Extraction and Ultrahigh Performance Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Liu, Hongcheng; Lin, Tao; Mao, Jia; Lu, Huan; Yang, Dongshun; Wang, Jiliang; Li, Qiwan

    2015-01-01

    A simple, accurate, and highly sensitive analytical method was developed for determining the paclobutrazol residue in potato and soil, the dynamics dissipation in soil. Extraction was carried out by low temperature partitioning and analyzed by ultrahigh performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). For a favor extraction yield, the parameters such as temperature and solvent were optimized. The result showed that sample would be easily frozen and separated using acetonitrile under −20°C for 10 min. The limit of detection (LOD) was 0.5 μg/kg, and the limit of quantification (LOQ) was 2 and 5 μg/kg for potato and soil, respectively. The influence of paclobutrazol residue in potato was evaluated. The possible contamination of paclobutrazol from surface can be rinsed by distilled water or peeled off, but the paclobutrazol in potato harvest comes mainly from absorption and transport, which could not be removed by peeling. The half-life of paclobutrazol in soil was 20.64 days, and the residue was below 0.22 mg/kg on 50th day after spraying. According to the risk assessment with Need Maximum Daily Intake (NEDI) and Acceptable Daily Intake (ADI), a Maximum Residue Limit (MRL) of paclobutrazol in potato was recommended as 1.0 mg/kg. PMID:26448896

  17. Determining mycotoxins in baby foods and animal feeds using stable isotope dilution and liquid chromatography tandem mass spectrometry.

    PubMed

    Zhang, Kai; Wong, Jon W; Krynitsky, Alexander J; Trucksess, Mary W

    2014-09-10

    We developed a stable isotope dilution assay with liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine multiple mycotoxins in baby foods and animal feeds. Samples were fortified with [(13)C]-uniformly labeled mycotoxins as internal standards ([(13)C]-IS) and prepared by solvent extraction (50% acetonitrile in water) and filtration, followed by LC-MS/MS analysis. Mycotoxins in each sample were quantitated with the corresponding [(13)C]-IS. In general, recoveries of aflatoxins (2-100 ng/g), deoxynivalenol, fumonisins (50-2000 ng/g), ochratoxin A (20-1000 ng/kg), T-2 toxin, and zearalenone (40-2000 ng/g) in tested matrices (grain/rice/oatmeal-based formula, animal feed, dry cat/dog food) ranged from 70 to 120% with relative standard deviations (RSDs) <20%. The method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxins at ng/g concentrations and deoxynivalenol and fumonisins at low μg/g concentrations in baby foods and animal feeds, without using conventional standard addition or matrix-matched calibration standards to correct for matrix effects. PMID:25153173

  18. [Simultaneous determination of 24 industrial dyes in grain and meat products by ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Feng, Yuechao; Jia, Li; He, Yahui; Wang, Jianfeng; Liu, Yan; Fan, Xiaojing

    2013-10-01

    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) analytical method was established for the simultaneous determination of 24 forbidden industrial dyes in grain and meat products. The sample was extracted with methanol and acetonitrile, and cleaned-up by a WAX solid phase extraction column. The solution was separated on an ACQUITY UPLC BEH C18 column eluted with a mixture of 10 mmol/L ammonium acetate-0.2% formic acid aqueous solution and methanol-acetonitrile (7:3, v/v) as the mobile phases, and then analyzed in multiple reaction monitoring (MRM) mode. The correlation coefficients were above 0.99, the average recoveries were 61%-116%, and the relative standard deviations (RSD, n = 6) were lower than 13%. The quantification limits were 0.1-4.0 microg/kg. This method is simple, effective, sensitive, and suitable for the determination and confirmation of the 24 forbidden industrial dyes in grain and meat products. PMID:24432648

  19. [Determination of five macrolide antibiotic residues in royal jelly samples by using high performance liquid chromatography tandem mass spectrometry].

    PubMed

    Xie, Wen; Ding, Huiying; Xi, Junyang; Qian, Yan; Huang, Leifang

    2007-05-01

    The macrolides are lipophilic molecules having a central lactone ring bearing 12 to 20 atoms to which several amino and/or neutral sugars are bound. They are broad spectrum antibiotics active against Gram-positive bacteria and mycoplasmas, as well as some Gram-negative organisms and members of the chlamydia group. Macrolides are a group of antibacterial compounds that have been widely used in medical and veterinary practices. A method of high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was developed for the confirmation of five macrolide antibiotic residues (spiramycin, oleandomycin, tylosin, roxithromycin, josamycin) in royal jelly samples. Trichloroacetic acid solution was used to precipitate the protein in the sample. The upper layer solution was extracted with acetonitrile. Then it was cleaned up with a C18 column. The one precursor/two product ion transitions for each macrolide antibiotics were monitored. The results show that the working curves for five macrolide antibiotics were linear in the range of 0.002 - 0.05 mg/L by HPLC-MS/MS in selective ion monitoring model. The limits of quantitation of the antibiotics in royal jelly were all 20 microg/kg. The recoveries were between 73.0% -90.2% at three spiked levels (20, 100 and 200 microg/kg for each macrolide antibiotic), and the relative standard deviations were between 5.6% - 10.5%. PMID:17679440

  20. Direct determination of glyphosate, glufosinate, and AMPA in soybean and corn by liquid chromatography/tandem mass spectrometry.

    PubMed

    Chamkasem, Narong; Harmon, Tiffany

    2016-07-01

    Glyphosate, glufosinate, and aminomethylphosphonic acid (AMPA) are amphoteric, low mass, high water soluble, and do not have chromophore. They are very difficult to be retained on a reversed phase HPLC and detected by UV or fluorescence detectors. A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed to determine these analytes in soybean and corn using a reversed phase with weak anion-exchange and cation-exchange mixed-mode Acclaim™ Trinity™ Q1 column. The sample was shaken with water containing ethylenediaminetetraacetic acid disodium salt (Na2EDTA) and acetic acid for 10 min to precipitate protein and extract the analytes into the solution. The supernatant was passed thru an Oasis HLB SPE to retain suspended particulates and non-polar interferences. The sample was directly injected and analyzed in 6 min by LC-MS/MS with no sample concentration or derivatization steps. Three isotopically labeled internal standards corresponding to each analyte were used to counter matrix suppression effect. Linearity of the detector response with a minimum coefficient of determination (R (2)) of more than 0.995 was demonstrated in the range of 10 to 1000 ng/mL for each analyte. Accuracy (recovery %) and precision (relative standard deviation or RSD %) were evaluated at the fortification levels of 0.1, 0.5, and 2 μg/g in seven replicates in both soybean and corn samples. PMID:27150204

  1. Liquid chromatography-tandem mass spectrometric assay for ponatinib and N-desmethyl ponatinib in mouse plasma.

    PubMed

    Sparidans, Rolf W; Kort, Anita; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

    2016-06-15

    Ponatinib is a multi-targeted third generation BCR-ABL1 tyrosine-kinase inhibitor approved for specific types of leukemia. A bioanalytical assay for this drug and its N-desmethyl metabolite in mouse plasma was developed and validated using liquid chromatography-tandem mass spectrometric (LC-MS/MS) with liquid-liquid extraction as sample pre-treatment procedure. After extraction with tert-butyl methyl ether of both analytes with their isotopically labeled internal standards and evaporation and reconstitution of the extract, compounds were separated by reversed-phase liquid chromatography under alkaline conditions. After electrospray ionization, both compounds were quantified in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The linear assay was validated in the ranges 5-5000ng/ml for ponatinib and 1-1000ng/ml for N-desmethyl ponatinib. Within-run (n=18) and between-run (3 runs; n=18) precisions were 10% and 12% at the lower limit of quantification for the metabolite, all other precisions were ≤8% for the metabolite and ≤6% for ponatinib. Accuracies were between 92 and 108% for both compounds in the whole calibration range. The drug was sufficiently stable under most relevant analytical conditions, only ponatinib showed more than 15% hydrolytic degradation after storage for 6h and longer at ambient temperature in mouse plasma. Finally, the assay was successfully applied to determine plasma drug levels and study pharmacokinetics after oral administration of ponatinib to female FVB mice. PMID:27179188

  2. Simultaneous Determination of Ticagrelor and Its Metabolites in Human Plasma and Urine Using Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Zhong, Wanping; Wang, Xipei; Tang, Lan; Mai, Liping; Chen, Xiao-Ping; He, Guodong; Zheng, Zhijie; Zhong, Shilong

    2016-07-01

    We have developed and validated a rapid, selective and sensitive method using high-performance liquid chromatography-tandem mass spectrometry (MS) for the quantification of ticagrelor and all of its as-yet-identified metabolites in human plasma and urine. For the analysis of ticagrelor, its metabolites and the internal standard (IS) plasma samples were processed by liquid-liquid extraction using ethyl acetate and urine was processed by protein precipitation. Separations were performed on an Ultimate XB-C18 column (2.1 mm × 150 mm, 3 μm), using aqueous ammonium acetate (0.025 mM)/acetonitrile (35 : 65, v:v) as the mobile phase. Ticagrelor and all 11 metabolites were eluted within 4.5 min. Quantification was performed using electrospray ionization, operating in negative ion mode. The ticagrelor and metabolite M8 (AR-C124910XX) responses were optimized at the m/z 521.2 → 361.2 and m/z 477.2 → 361.1 transitions, respectively. The assay was validated over the linear range of 0.5-2,000 ng/mL for ticagrelor and M8. The intra- and inter-assay precisions were ≤14.6% for ticagrelor and ≤14.7% for M8, respectively. The matrix effects of plasma and urine were in the range of 98.3-110.7% for ticagrelor and 102.1-112.3% for M8. The relative quantification of other metabolites was performed by assessing the ratio of metabolite to IS peaks. The newly developed method was successfully used in a pharmacokinetic study characterizing ticagrelor metabolism in human volunteers. PMID:27165805

  3. Determination of albendazole and metabolites in silkworm Bombyx mori hemolymph by ultrafast liquid chromatography tandem triple quadrupole mass spectrometry.

    PubMed

    Li, Li; Xing, Dong-Xu; Li, Qing-Rong; Xiao, Yang; Ye, Ming-Qiang; Yang, Qiong

    2014-01-01

    Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO2) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO2-NH2). Calibration curves had good linearities with R2 of 0.9905-0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO2 and 5.94 ng/mL for ABZSO2-NH2. Recoveries were 93.12%-103.83% for ABZ, 66.51%-108.51% for ABZSO, 96.85%-105.6% for ABZSO2 and 96.46%-106.14% for ABZSO2-NH2, (RSDs <8%). Accuracy, precision and stability tests showed acceptable variation in quality control (QC) samples. This analytical method successfully determined albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO2 increased and then fell, while ABZSO2-NH2 level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO2 rising over time. PMID:25255321

  4. Biomonitoring method for bisphenol A in human urine by ultra-high-performance liquid chromatography-tandem mass spectrometry

    PubMed Central

    Anderson, David J.; Brozek, Eric M.; Cox, Kyley J.; Porucznik, Christina A.; Wilkins, Diana G.

    2014-01-01

    An ultra-high-performance liquid chromatography-tandem mass spectrometry method for the measurement of total bisphenol A in human urine was developed and validated. The method utilized liquid/liquid extraction with 1-chlorobutane and a human urine aliquot size of 800 µL. Chromatography was performed on an Acquity UPLC® system with a Kinetex® Phenyl-Hexyl column. Mass spectrometric analysis was with negative electrospray ionization on a Quattro Premier XE™. The surrogate matrix method was used for the preparation of calibration standards in synthetic urine due to the presence of BPA in control human urine. The validated calibration range was 0.75 to 20 ng/mL with a limit of detection of 0.1 ng/mL. The internal standard was d16-bisphenol A. Method validation utilized quality control samples at three concentrations in both synthetic urine and human urine. Bisphenol A mono-glucuronide was fortified in synthetic urine in each analytical run to monitor the enzymatic conversion of the glucuronide conjugate to BPA by β-glucuronidase. Validated method parameters included linearity, accuracy, precision, integrity of dilution, selectivity, re-injection reproducibility, recovery/matrix effect, solution stability, and matrix stability in human urine. Acceptance criteria for analytical standards and QCs were ± 20% of nominal concentration. Matrix stability in human urine was validated after 24 hours at ambient temperature, after three freeze/thaw cycles, and after frozen storage at −20 °C and −80 °C for up to 218 days. The method has been applied to the analysis of over 1750 human urine samples from a biomonitoring study. The median and mean urine BPA concentrations were 2.71 ng/mL and 4.75 ng/mL, respectively. PMID:24594944

  5. Simultaneous determination of opiates, methadone, buprenorphine and metabolites in human urine by superficially porous liquid chromatography tandem mass spectrometry.

    PubMed

    Lin, Huei-Ru; Chen, Chin-Lun; Huang, Chieh-Liang; Chen, Shao-Tsu; Lua, Ahai-Chuang

    2013-04-15

    For monitoring compliance of methadone or buprenorphine maintenance patient, a method for the simultaneous determination of methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), buprenorphine, norbuprenorphine, opiates (morphine, codeine, 6-monoacetylmorphine) in urine by superficially porous liquid chromatography tandem mass spectrometry was developed and validated. After enzyme digestion and liquid-liquid extraction, reverse-phase separation was achieved in 5.2 min and quantification was performed by multiple reaction monitoring. Chromatographic separation was performed at 40 °C on a reversed phase Poroshell column with gradient elution. The mobile phase consisted of water and methanol, each containing 0.1% formic acid, at a flow rate of 0.32 mL/min. Intra-day and inter-day precision were less than 12.1% and accuracy was between -9.8% and 13.7%. Extraction efficiencies were more than 68%. Although ion suppression was detected, deuterated internal standards compensated for these effects. Carryover was minimal, less than 0.20%. All analytes were stable at room temperature for 16 h, 4 °C for 72 h, and after three freeze-thaw cycles. The assay also fulfilled compound identification criteria in accordance with the European Commission Decision 2002/657/EC. We analyzed 62 urine samples from patients received maintenance therapy and found that 54.8% of the patient samples tested were detected for morphine, codeine, or 6-monoacetylmorphine. This method provides a reliable and simultaneous quantification of opiates, maintenance drugs, and their metabolites in urine samples. It facilitates the routine monitoring in individuals prescribed the drug to ensure compliance and help therapeutic process. PMID:23507455

  6. Simultaneous determination of trantinterol and its metabolites in rat urine and feces by liquid chromatography-tandem mass spectrometry.

    PubMed

    Li, Kunjie; Wang, Yanjuan; Zhang, Lili; Qin, Feng; Guo, Xingjie; Li, Famei

    2013-09-01

    A highly selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of trantinterol (SPFF) and its major metabolites for the first time. The analytes were extracted from rat urine and feces samples by liquid-liquid extraction (LLE) and determined in multiple reaction monitoring (MRM) mode with clenbuterol as the internal standard. Chromatographic separation was achieved on a Venusil ASB C8 column (2.1mm×100mm, 3μm), with the mobile phase consisted of methanol-0.2% formic acid (30:70, v/v) at the flow rate of 0.2mL/min. Each sample was chromatographed within 5min. This method has a lower limit of quantification (LLOQ) of 0.450, 1.05, 1.35, 0.904 and 1.36ng/mL for trantinterol (SPFF), arylhydroxylamine trantinterol (N-OH-SPFF), tert-butyl hydroxylated trantinterol (Tert-OH-SPFF), 1-carbonyl trantinterol (SPFF-COOH) and 3-methyl sulfone-dechloro-trantinterol (SPFF-SO2CH3) in rat urine, and 0.450, 1.35 and 0.904ng/mL for SPFF, Tert-OH-SPFF and SPFF-COOH in rat feces, respectively. The linear correlation coefficients were greater than 0.990. The intra- and inter-day precision (relative standard deviation, RSD) values were below 15% and the accuracy (relative error, RE) was -9.9% to 11% at three quality control levels. The method has been successfully applied to the excretion study following an oral administration of 1mg/kg trantinterol to rats. PMID:23911540

  7. Determination of afloqualone in human plasma using liquid chromatography/tandem mass spectrometry: Application to pharmacokinetic studies in humans.

    PubMed

    Yun, Hwi-Yeol; Lee, Seo-Pan; Jeong, Hae Hum; Yoon, Young-Ran; Sohn, Soo Jung; Kim, Sang Kyum; Kang, Wonku; Kwon, Kwang-Il

    2007-10-15

    Two methods for determining the central-acting muscle relaxant afloqualone in human plasma were developed and compared using API2000 and API4000 liquid chromatography tandem mass spectrometry (LC/MS/MS) systems. In the API2000 LC/MS/MS system, afloqualone and the internal standard methaqualone were extracted from plasma using a methyl-tertiary ether. After drying the organic layer, the residue was reconstituted in a mobile phase (0.1% formic acid-acetonitrile:0.1% formic acid buffer, 80:20 v/v) and injected onto a reversed-phase C(18) column. The isocratic mobile phase was eluted at 0.2ml/min. The ion transitions monitored in multiple reaction-monitoring mode were m/z 284-->146 and 251-->117 for afloqualone and methaqualone, respectively. Sample preparation for the API4000LC/MS/MS system involved simple protein precipitation with an organic mixture (methanol:10% ZnSO(4)=8:2). The ion transitions monitored in multiple reaction-monitoring mode were m/z 284-->146 and 251-->131 for afloqualone and methaqualone, respectively. In both assays, the coefficient of variation of the precision was less than 11.8%, the accuracy exceeded 91.5%, the limit of quantification was 0.5ng/ml, and the limit of detection was 0.1ng/ml for afloqualone. Two methods were used to measure the plasma afloqualone concentration in healthy subjects after a single oral 20-mg dose of afloqualone. During subsequent application of the methods, we observed that high-concentration plasma samples (>7ng/ml) prepared using the protein precipitation method resulted in about 20% higher afloqualone concentrations than with plasma samples prepared using the liquid-liquid extraction method. We believe that this phenomenon was related to the cleanness of the sample and its chemical nature. PMID:19073082

  8. Analysis of daphnane orthoesters in poisonous Australian pimelea species by liquid chromatography-tandem mass spectrometry.

    PubMed

    Chow, Sharon; Fletcher, Mary T; McKenzie, Ross A

    2010-06-23

    Cattle grazing in arid rangelands of Australia suffer periodic extensive and serious poisoning by the plant species Pimelea trichostachya, P. simplex, and P. elongata. Pimelea poisoning (also known as St. George disease and Marree disease) has been attributed to the presence of the diterpenoid orthoester simplexin in these species. However, literature relating to previous studies is complicated by taxonomic revisions, and the presence of simplexin has not previously been verified in all currently recognized taxa capable of inducing pimelea poisoning syndrome, with no previous chemical studies of P. trichostachya (as currently classified) or P. simplex subsp. continua. We report here the isolation of simplexin from P. trichostachya and the development of a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method to measure simplexin concentrations in pimelea plant material. Simplexin was quantified by positive-ion atmospheric pressure chemical ionization (APCI) LC-MS/MS with selected reaction monitoring (SRM) of the m/z 533.3 > 253.3 transition. LC-MS/MS analysis of the four poisonous taxa P. trichostachya, P. elongata, P. simplex subsp. continua, and P. simplex subsp. simplex showed similar profiles with simplexin as the major diterpenoid ester component in all four taxa accompanied by varying amounts of related orthoesters. Similar analyses of P. decora, P. haematostachya, and P. microcephala also demonstrated the presence of simplexin in these species but at far lower concentrations, consistent with the limited reports of stock poisoning associated with these species. The less common, shrubby species P. penicillaris contained simplexin at up to 55 mg/kg dry weight and would be expected to cause poisoning if animals consumed sufficient plant material. PMID:20507137

  9. Determination of pharmaceuticals in biosolids using accelerated solvent extraction and liquid chromatography/tandem mass spectrometry.

    PubMed

    Ding, Yunjie; Zhang, Weihao; Gu, Cheng; Xagoraraki, Irene; Li, Hui

    2011-01-01

    An analytical method was developed to quantitatively determine pharmaceuticals in biosolid (treated sewage sludge) from wastewater treatment plants (WWTPs). The collected biosolid samples were initially freeze dried, and grounded to obtain relatively homogenized powders. Pharmaceuticals were extracted using accelerated solvent extraction (ASE) under the optimized conditions. The optimal operation parameters, including extraction solvent, temperature, pressure, extraction time and cycles, were identified to be acetonitrile/water mixture (v/v 7:3) as extraction solvent with 3 extraction cycles (15 min for each cycle) at 100 °C and 100 bars. The extracts were cleaned up using solid-phase extraction followed by determination by liquid chromatography coupled with tandem mass spectrometry. For the 15 target pharmaceuticals commonly found in the environment, the overall method recoveries ranged from 49% to 68% for tetracyclines, 64% to 95% for sulfonamides, and 77% to 88% for other pharmaceuticals (i.e. acetaminophen, caffeine, carbamazepine, erythromycin, lincomycin and tylosin). The developed method was successfully validated and applied to the biosolid samples collected from WWTPs located in six cities in Michigan. Among the 15 target pharmaceuticals, 14 pharmaceuticals were detected in the collected biosolid samples. The average concentrations ranged from 2.6 μg/kg for lincomycin to 743.6 μg/kg for oxytetracycline. These results indicated that pharmaceuticals could survive wastewater treatment processes, and accumulate in sewage sludge and biosolids. Subsequent land application of the contaminated biosolids could lead to the dissemination of pharmaceuticals in soil and water environment, which poses potential threats to at-risk populations in the receiving ecosystems. PMID:21112593

  10. Simultaneous Quantification of Free and Glucuronidated Cannabinoids in Human Urine by Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Scheidweiler, Karl B.; Desrosiers, Nathalie A.; Huestis, Marilyn A.

    2012-01-01

    Background Cannabis is the most commonly abused drug of abuse and is commonly quantified during urine drug testing. We conducted a controlled drug administration studies investigating efficacy of urinary cannabinoid glucuronide metabolites for documenting recency of cannabis intake and for determining stability of urinary cannabinoids. Methods A liquid chromatography tandem mass spectrometry method was developed and validated quantifying Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol, cannabinol, THC-glucuronide and THCCOOH-glucuronide in 0.5 ml human urine via supported-liquid extraction. Chromatography was performed on an Ultra Biphenyl column with a gradient of 10 mmol/l ammonium acetate, pH 6.15 and 15% methanol in acetonitrile at 0. 4ml/min. Analytes were monitored by positive and negative mode electrospray ionization and multiple reaction monitoring mass spectrometry. Results Linear ranges were 0.5–50 ng/ml for THC-glucuronide, 1–100 ng/ml for THCCOOH, 11-OH-THC and cannabidiol, 2–100 ng/ml for THC and cannabinol, and 5–500 ng/ml for THCCOOH-glucuronide (R2>0.99). Mean extraction efficiencies were 34–73% with analytical recovery (bias) 80.5–118.0% and total imprecision 3.0–10.2% coefficient of variation. Conclusion This method simultaneously quantifies urinary cannabinoids and phase II glucuronide metabolites, and enables evaluation of urinary cannabinoid glucuronides for documenting recency of cannabis intake and cannabinoid stability. The assay is applicable for routine urine cannabinoid testing. PMID:22771478

  11. A validated liquid chromatography-tandem mass spectrometry method for the quantitative determination of 4β-hydroxycholesterol in human plasma.

    PubMed

    van de Merbel, Nico C; Bronsema, Kees J; van Hout, Mischa W J; Nilsson, Ralf; Sillén, Henrik

    2011-07-15

    A novel liquid chromatography-tandem mass spectrometry method is described for the quantitative determination of the endogenous CYP 3A4/5 marker 4β-hydroxycholesterol in human K(2)-EDTA plasma. It is based on alkaline hydrolysis to convert esterified to free 4β-hydroxycholesterol, followed by analyte extraction from plasma by hexane and purification of the hexane extract by normal-phase solid-phase extraction. The analyte is chromatographically separated from endogenous isobaric plasma oxysterols and excess cholesterol by a 16-min reversed-phase gradient on a C18 column; detection is performed by atmospheric pressure photoionization tandem mass spectrometry in the positive ion mode, using toluene as a dopant. Using 400μl of plasma, 4β-hydroxycholesterol can be quantified in the concentration range 10.0-250nM. Validation results show that the method is sufficiently selective towards endogenous plasma sterols and capable of quantifying the analyte with good precision and accuracy. The analyte is sufficiently stable in all relevant matrices and solvents; the addition of the anti-oxidant butylated hydroxytoluene to prevent in vitro formation of 4β-hydroxycholesterol from cholesterol during storage or analysis is not necessary, provided that long-term frozen storage of plasma occurs at -70°C. PMID:21507593

  12. Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp.

    PubMed

    Chen, Guoqiang; Hoptroff, Michael; Fei, Xiaoqing; Su, Ya; Janssen, Hans-Gerd

    2013-11-22

    A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal standard. Atmospheric pressure chemical ionization (APCI) in positive mode was applied for the detection of climbazole. For quantification, multiple reaction monitoring (MRM) transition 293.0>69.0 was monitored for climbazole, and MRM transition 296.0>225.1 for the deuterated climbazole. The linear range ran from 4 to 2000 ng mL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 1 ng mL(-1) and 4 ng mL(-1), respectively, which enabled quantification of climbazole on artificial skin and human scalp at ppb level (corresponding to 16 ng cm(-2)). For the sampling of climbazole from human scalp the buffer scrub method using a surfactant-modified phosphate buffered saline (PBS) solution was selected based on a performance comparison of tape stripping, the buffer scrub method and solvent extraction in in vitro studies. Using this method, climbazole deposition in in vitro and in vivo studies was successfully quantified. PMID:23958691

  13. Identification and quantification of psychoactive drugs in whole blood using dried blood spot (DBS) by ultra-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Kyriakou, Chrystalla; Marchei, Emilia; Scaravelli, Giulia; García-Algar, Oscar; Supervía, August; Graziano, Silvia

    2016-09-01

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of twenty three psychoactive drugs and metabolites in whole blood using dried blood spot (DBS). Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.1% formic acid in acetonitrile and 5mM ammonium formate at pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electro-spray ionization. The method was linear from the limit of quantification (5ng/ml for all the analytes apart from 15ng/ml for Δ-9-tetrahydrocannabinol and metabolites) to 500ng/ml, and showed good correlation coefficients (r(2)=0.990) for all substances. Analytical recovery of analytes under investigation was always higher than 75% and intra-assay and inter-assay precision and accuracy always better than 15%. Using the validated method, ten DBS samples, collected at the hospital emergency department in cases of acute drug intoxication, were found positive to one or more psychoactive drugs. Our data support the potential of DBS sampling for non invasive monitoring of exposure/intoxication to psychoactive drugs. PMID:27232151

  14. Development of a new method for the identification of degradation products of V-type nerve agents by liquid chromatography-tandem mass spectrometry.

    PubMed

    Lee, Jin Young; Lee, Yong Han

    2014-01-01

    Degradation products of V-type nerve agents are important markers of these toxic chemical warfare agents; hence their detection and identification are of high importance from verification point of view of Chemical Weapons Convention. The new analytical technique using quantitation-enhanced data-dependent (QED) method has been developed for the analysis of the degradation products, 2-(N,N-dialkylamino)ethanesulfonic acids of V-type nerve agents, by using liquid chromatography-tandem mass spectrometry (Thermo-Scientific Vantage triple stage quadrupole mass spectrometer, Thermo Finnigan Surveyor, San Jose, CA, USA) via an atmospheric pressure ionization source/interface operated in eletrospray ionization mode. With a single analytical run, we could perform the quantitative analysis of the 2-(N,N-dialkylamino)ethanesulfonic acids by the selected reaction monitoring scan mode with limit of detection at 0.1 ng/mL and identify their isomeric compounds by product ion scan mode, simultaneously. The QED method will be applicable to the trace analysis of degradation products of V-type nerve agents in the environmental matrices in the Organisation for the Prohibition of Chemical Weapons proficiency test. PMID:24470166

  15. [Direct quantitative analysis of amino acids in fermented beverage of plant extract using high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Zheng, Zhong; Sun, Qi; Shi, Yongwei; Qu, Jiale; Song, Fengruil; Liu, Zhiqiang

    2015-03-01

    A method was established for underivatized amino acid determination in fermented beverage of plant extract. Samples were diluted with methanol for five times, extracted by ultrasonic vibration for 30 min, and high-speed centrifuged for 15 min at 10,000 r/min. The supernatant was separated and detected by, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The chromatographic column was Venusil ASB C18 (250 mm x 4.6 mm, 5 µm). The elution was performed at a flow rate of 0.5 mL/min using the mobile phases of methanol-acetic acid-water mixture. The MS detector was set as follows: ion source voltage 3 kV, ion source temperature 150 t, solvent temperature 350 t, gas flow rate 800 L/h. The collision gas was argon with a pressure of 0.17 Pa. The quantitation analysis was carried out with peak area in extracted ion chromatograms. Good linearities were acquired in the range of 0.5-200 µmol/L (r2 > 0.99) for the amino acids. The recoveries were between 86% and 110%. There were 16 amino acids in the fermented beverage of plant extract quantitatively analyzed. The method is simple, rapid, accurate and reliable in quantitative analysis of amino acid samples in the fields of pharmaceutical, food and natural products. PMID:26182474

  16. Multimycotoxin analysis in water and fish plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    Tolosa, J; Font, G; Mañes, J; Ferrer, E

    2016-02-01

    High performance liquid chromatography-mass spectrometry was used for the determination of 15 mycotoxins in water and fish plasma samples, including aflatoxins, fumonisins, ochratoxin A, sterigmatocistin, fusarenon-X and emerging Fusarium mycotoxins. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a sample treatment for the simultaneous extraction of mycotoxins. Results showed differences in recovery assays when different extraction solvents were employed. Ethyl acetate showed better recoveries for the major part of mycotoxins analyzed, except for aflatoxins B2, G1 and G2, which showed better recoveries when employing chloroform as extractant solvent. Fumonisins and beauvericin exhibited low recoveries in both water and plasma. This method was validated according to guidelines established by European Commission and has shown to be suitable to be applied in dietary and/or toxicokinetic studies in fish where is necessary to check mycotoxin contents in rearing water and fish plasma. PMID:26694790

  17. Determination of phentermine, N-hydroxyphentermine and mephentermine in urine using dilute and shoot liquid chromatography-tandem mass spectrometry.

    PubMed

    Choi, Yun Jeong; Sim, Arum; Kim, Min Kyung; Suh, Sunglll; In, Moon Kyo; Kim, Jin Young

    2016-09-01

    Nonmedical use of prescription stimulants such as phentermine (PT) has been regulated by law enforcement authorities due to its euphorigenic and relaxing effects. Due to high potential for its abuse, reliable analytical methods were required to detect and identify PT and its metabolite in biological samples. Thus a dilute and shoot liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for simultaneous determination of PT, N-hydroxyphentermine (NHOPT) and mephentermine (MPT) in urine. A 5μL aliquot of diluted urine was injected into the LC-MS/MS system. Chromatographic separation was performed by reversed-phase C18 column with gradient elution for all analytes within 5min. Identification and quantification were based on multiple reaction monitoring (MRM) detection. Linear least-squares regression with a 1/x(2) weighting factor was used to generate a calibration curve and the assay was linear from 50 to 15000ng/mL (PT and MPT) and 5 to 750ng/mL (NHOPT). The intra- and inter-day precisions were within 8.9% while the intra- and inter-day accuracies ranged from -6.2% to 11.2%. The limits of quantification were 3.5ng/mL (PT), 1.5ng/mL (NHOPT) and 1.0ng/mL (MPT). Method validation requirements for selectivity, dilution integrity, matrix effect and stability were satisfied. The applicability of the developed method was examined by analyzing urine samples from drug abusers. PMID:27398632

  18. Simultaneous Measurement of Serum Chemical Castration Agents and Testosterone Levels Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Ko, Dae-Hyun; Lee, Kyunghoon; Jeon, Sun-Hee; Song, Sang Hoon; Yun, Yeo-Min; Chun, Sail; Kim, Hee Seung; Kim, Jin Young; In, Moon Kyo; Song, Junghan

    2016-05-01

    Chemical castration involves administration of drugs to prevent pathological sexual behavior, reduce abnormal sexual drive and treat hormone-dependent cancers. Various drugs have been used for chemical castration; however, substantial interindividual variability and side effects are often observed. In this study, we proposed a useful monitoring method for the application of chemical castration agents using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS). Testosterone, cyproterone acetate, medroxyprogesterone, goserelin acetate, leuprolide acetate and triptorelin acetate were analyzed by UPLC-MS-MS. The target drugs were extracted from serum samples by double protein precipitation using methanol. Testosterone-1,2-d2 and buserelin acetate were used as internal standards. Parameters of analytical performance were evaluated, including imprecision, linearity, ion suppression and detection capabilities. Testosterone measurements were compared with the results of immunoassays. Serum specimens from 51 subjects who underwent chemical castration were analyzed. All drugs and testosterone were well extracted and separated using our method. The method was essentially free from potential interferences and ion suppression. Within-run and between-run imprecision values were <15%. The lower limits of quantification were 0.125 and 0.5-1.0 ng/mL for testosterone and other drugs, respectively. Good correlations with pre-existing immunoassays for testosterone measurement were observed. Sera from subjects who underwent androgen deprivation therapy showed variable levels of drugs. We successfully developed a UPLC-MS-MS-based monitoring method for chemical castration. The performance of our method was generally acceptable. This method may provide a novel monitoring strategy for chemical castration to enhance expected effects while reducing unwanted side effects. PMID:26989223

  19. [Simultaneous determination of seven sex hormones in fish products using ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Aizhi; Wang, Quanlin; Shen, Jian; Zhang, Shufen; Chen, Liren

    2010-02-01

    A rapid, specific and highly sensitive method for the determination of seven sex hormones (norgestrel, methyltestosterone, testosterone propionate, medroxyprogesterone acetate, megestrol acetate, chlormadinone acetate, and nandrolone) residues in fish products was developed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with electrospray ionization (ESI) in positive mode. The target compounds were extracted with methanol after the enzyme hydrolysis of the fish products. ZnCl2 was added to the extract solution to remove lipids. Then target compounds were purified by an LC-C18 and an LC-NH2 solid phase extraction cartridges. The target compounds were separated on a Waters ACQUITY UPLC BEH-C18 column (100 mm x 2.1 mm, 1.7 microm) and detected qualitatively and quantitatively in multi reaction monitoring (MRM) mode. For the seven sex hormones, the limits of detection (LOD) of the method were from 0.08 to 0.17 microg/kg and the limits of quantification (LOQ) were in the range of 0.24 -0.58 microg/kg. At the spiked levels of 1 and 4 microg/kg, the average recoveries ranged from 76% to 118% with the relative standard deviations between 5.0% and 11.3% for the seven sex hormones using internal standard method; and the average recoveries ranged from 66% to 94% with the relative standard deviations between 4.5% and 10.7% using matrix matched external standard method. The results showed that both methods are able to meet the multi-residue detection of the seven sex hormone residues in fish products. The degreased large yellow croaker and roast fish fillet real samples from a local market were detected by the developed method, and the seven targets were not found. PMID:20556960

  20. A simple sample pretreatment method for multi-mycotoxin determination in eggs by liquid chromatography tandem mass spectrometry.

    PubMed

    Zhu, Runyue; Zhao, Zhiyong; Wang, Jianhua; Bai, Bing; Wu, Aibo; Yan, Liping; Song, Suquan

    2015-10-23

    In this study, a reliable and fast method using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure without any clean-up step was developed for simultaneous extraction of 15 mycotoxins, i.e., aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1, aflatoxin M2, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, de-epoxy-DON, zearalenone, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol, from eggs. High-performance liquid chromatography tandem mass spectrometry was used to separate and detect all of the analytes. Electrospray ionization at both negative and positive modes and multiple reaction-monitoring mode were applied to detect these analytes. The main factors, such as extraction time, extraction solvent, evaporation temperature, and pH of the solvent, were carefully optimized to improve the extraction efficiency. The coefficients of determination of the calibration curves ranged from 0.9884 to 0.9998. The recoveries of most of the analytes were between 71.3% and 105.4% at three concentration levels, except for AFB1 that showed recovery rates of not more than 67.5% in all concentrations. The repeatability and intra-lab reproducibility of this method were both lower than 15% and 25%, respectively. The limit of quantification ranged from 0.2 μg/kg to 5 μg/kg. The matrix effect was evaluated and reduced by the use of matrix-matched calibration curves. The validated method was applied in a pilot study to analyze mycotoxin contamination in 12 eggs, and trace amounts of deoxynivalenol, 15-acetyldeoxynivalenol, aflatoxin B1, aflatoxin G2, zearalenone and β-zearalenol were detected in these samples. PMID:26385084

  1. Simultaneous determination of guanidinosuccinic acid and guanidinoacetic acid in urine using high performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Saigusa, Daisuke; Suzuki, Naoto; Takahashi, Mai; Shiba, Kanako; Tanaka, Satoshi; Abe, Takaaki; Hishinuma, Takanori; Tomioka, Yoshihisa

    2010-09-16

    We present a method for the simultaneous determination of guanidinosuccinic acid (GSA) and guanidinoacetic acid (GAA) from urine by protein precipitation and liquid chromatography/tandem mass spectrometry. The chromatographic separation was performed using a cation exchange column with an elution gradient of 0.1 mM and 20 mM ammonium acetate buffers. GSA was detected with the mass spectrometer in negative ion mode monitoring at m/z 174.1, and GAA, creatinine, arginine, and homoarginine were in positive ion mode monitoring at m/z 118.1, 114.1, 175.1, and 189.1, respectively. As an internal standard, L-arginine-(13)C(6) hydrochloride and creatinine-d(3) (methyl-d(3)) were used. The calibration ranges were 0.50-25.0 μg mL(-1), and good linearities were obtained for all compounds (r>0.999). The intra- and inter-assay accuracies (expressed as recoveries) and precisions at three concentration levels (1.00, 5.00 and 25.0 μg mL(-1)) were better than 83.8% and 7.41%, respectively. The analytical performance of the method was evaluated by determination of the compounds in urine from male C57BL/J Iar db/db diabetes mellitus (DM) mice. The values of GSA and GAA corrected by the ratios of the individual compounds to creatinine were significantly increased in DM mice compared with control mice. These results indicated that the newly developed method was useful for determining urinary guanidino compounds and metabolites of arginine. PMID:20837184

  2. Simultaneous quantitative analysis of eight vitamin D analogues in milk using liquid chromatography-tandem mass spectrometry.

    PubMed

    Gomes, Fabio P; Shaw, P Nicholas; Whitfield, Karen; Hewavitharana, Amitha K

    2015-09-01

    Milk is an important source of nutrients for various risk populations, including infants. The accurate measurement of vitamin D in milk is necessary to provide adequate supplementation advice for risk groups and to monitor regulatory compliance. Currently used liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods are capable of measuring only four analogues of vitamin D in unfortified milk. We report here an accurate quantitative analytical method for eight analogues of vitamin D: Vitamin D2 and D3 (D2 and D3), 25-hydroxy D2 and D3, 24,25-dihydroxy D2 and D3, and 1,25-dihydroxyD2 and D3. In this study, we compared saponification and protein precipitation for the extraction of vitamin D from milk and found the latter to be more effective. We also optimised the pre-column derivatisation using 4-phenyl-l,2,4-triazoline-3,5-dione (PTAD), to achieve the highest sensitivity and accuracy for all major vitamin D forms in milk. Chromatography was optimised to reduce matrix effects such as ion-suppression, and the matrix effects were eliminated using co-eluting stable isotope labelled internal standards for the calibration of each analogue. The analogues, 25-hydroxyD3 (25(OH)D3) and its epimer (3-epi-25(OH)D3) were chromatographically resolved, to prevent over-estimation of 25(OH)D3. The method was validated and subsequently applied for the measurement of total vitamin D levels in human, cow, mare, goat and sheep milk samples. The detection limits, repeatability standard deviations, and recovery ranges were from 0.2 to 0.4 femtomols, 6.30-13.5%, and 88.2-105%, respectively. PMID:26388380

  3. 11-Nor-9-carboxy-∆9-tetrahydrocannabinol quantification in human oral fluid by liquid chromatography-tandem mass spectrometry.

    PubMed

    Scheidweiler, Karl B; Himes, Sarah K; Chen, Xiaohong; Liu, Hua-Fen; Huestis, Marilyn A

    2013-07-01

    Currently, ∆9-tetrahydrocannabinol (THC) is the analyte quantified for oral fluid cannabinoid monitoring. The potential for false-positive oral fluid cannabinoid results from passive exposure to THC-laden cannabis smoke raises concerns for this promising new monitoring technology. Oral fluid 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH) is proposed as a marker of cannabis intake since it is not present in cannabis smoke and was not measureable in oral fluid collected from subjects passively exposed to cannabis. THCCOOH concentrations are in the picogram per milliliter range in oral fluid and pose considerable analytical challenges. A liquid chromatography-tandem mass spectrometry (LCMSMS) method was developed and validated for quantifying THCCOOH in 1 mL Quantisal-collected oral fluid. After solid phase extraction, chromatography was performed on a Kinetex C18 column with a gradient of 0.01% acetic acid in water and 0.01% acetic acid in methanol with a 0.5-mL/min flow rate. THCCOOH was monitored in negative mode electrospray ionization and multiple reaction monitoring mass spectrometry. The THCCOOH linear range was 12-1,020 pg/mL (R(2) > 0.995). Mean extraction efficiencies and matrix effects evaluated at low and high quality control (QC) concentrations were 40.8-65.1 and -2.4-11.5%, respectively (n = 10). Analytical recoveries (bias) and total imprecision at low, mid, and high QCs were 85.0-113.3 and 6.6-8.4% coefficient of variation, respectively (n = 20). This is the first oral fluid THCCOOH LCMSMS triple quadrupole method not requiring derivatization to achieve a <15 pg/mL limit of quantification. The assay is applicable for the workplace, driving under the influence of drugs, drug treatment, and pain management testing. PMID:23681203

  4. Development and validation of a liquid chromatography-tandem mass spectrometric assay for quantitative analyses of triptans in hair.

    PubMed

    Vandelli, Daniele; Palazzoli, Federica; Verri, Patrizia; Rustichelli, Cecilia; Marchesi, Filippo; Ferrari, Anna; Baraldi, Carlo; Giuliani, Enrico; Licata, Manuela; Silingardi, Enrico

    2016-04-01

    Triptans are specific drugs widely used for acute treatment of migraine, being selective 5HT1B/1D receptor agonists. A proper assumption of triptans is very important for an effective treatment; nevertheless patients often underuse, misuse, overuse or use triptans inconsistently, i.e., not following the prescribed therapy. Drug analysis in hair can represent a powerful tool for monitoring the compliance of the patient to the therapy, since it can greatly increase the time-window of detection compared to analyses in biological fluids, such as plasma or urine. In the present study, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the quantitative analysis in human hair of five triptans commonly prescribed in Italy: almotriptan (AL), eletriptan (EP), rizatriptan (RIZ), sumatriptan (SUM) and zolmitriptan (ZP). Hair samples were decontaminated and incubated overnight in diluted hydrochloric acid; the extracts were purified by mixed-mode SPE cartridges and analyzed by LC-MS/MS under gradient elution in positive multiple reaction monitoring (MRM) mode. The procedure was fully validated in terms of selectivity, linearity, limit of detection (LOD) and lower limit of quantitation (LLOQ), accuracy, precision, carry-over, recovery, matrix effect and dilution integrity. The method was linear in the range 10-1000pg/mg hair, with R(2) values of at least 0.990; the validated LLOQ values were in the range 5-7pg/mg hair. The method offered satisfactory precision (RSD <10%), accuracy (90-110%) and recovery (>85%) values. The validated procedure was applied on 147 authentic hair samples from subjects being treated in the Headache Centre of Modena University Hospital in order to verify the possibility of monitoring the corresponding hair levels for the taken triptans. PMID:26970848

  5. Pharmacokinetics, tissue distribution and excretion of peimisine in rats assessed by liquid chromatography-tandem mass spectrometry.

    PubMed

    Chen, Lihua; Li, Dongxun; Zhang, Guosong; Zhang, Wei; Zhang, Lihua; Guan, Yongmei; Zhu, Weifeng; Liu, Hongning

    2015-06-01

    Peimisine, the common ingredient of "zhebeimu" groups and "chuanbeimu" groups, is responsible for the expectorant and cough relieving effects. The aim of this study was to investigate the pharmacokinetics, tissue distribution and excretion of peimisine in male and female SD (Sprague-Dawley) rats by a rapid and sensitive LC-MS/MS (liquid chromatography-tandem mass spectrometry) method used carbamazepine as the internal standard after oral administration, carbamazepine was stated as an IS. The results showed that peimisine was slowly distributed, and eliminated from rat plasma and manifested linear dynamics in a dose range of 0.26-6.5 mg/kg. Tested by ANOVA, there were gender differences in the pharmacokinetic parameters of AUC(0-t), AUC(0-∞) among a single dose of 0.26, 1.3, 6.5 mg/kg (P < 0.05). Drug blood and tissue levels in male rats were significantly higher than the female counterparts after oral administration, while both the males and the females showed high drug levels in spleen, kidney, lung, liver and heart. On the other hand, the peimisine levels that can be reached in uterus, ovary, testis and brain is low. The excretion study showed that little administered peimisine (<0.7%) was recovered in the male and female bile. Approximately 13.46 and 15.05% were recovered in female urine and feces, while 43.07 and 7.49% were recovered in male urine and feces, respectively, which indicated that the major elimination route of male rats was urine excretion. In addition, there was significant differences in total cumulative excretive ratio of peimisine in feces (P < 0.05) and no significant differences in the urine (P > 0.05) at a dose of 1.3 mg/kg. PMID:25001900

  6. Pharmacokinetic study of ACT-132577 in rat plasma by ultra performance liquid chromatography-tandem mass spectrometry

    PubMed Central

    Zhang, Jin; Geng, Peiwu; Luo, Xinhua; Zhou, Genzhi; Lin, Yingying; Zhang, Lijing; Wang, Shuanghu; Wen, Congcong; Ma, Jianshe; Ding, Ting

    2015-01-01

    It was reported that macitentan was metabolized predominantly by cytochrome P450 3A4, and ACT-132577, its pharmacologically active metabolite, is fivefold less potent at blocking ET receptors than macitentan. In this work, a sensitive and selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of ACT-132577 in rat plasma was developed and validated. After addition of diazepam as an internal standard (IS), protein precipitation by acetonitrile was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with 0.2% formic acid and methanol as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 546.9→200.6 for ACT-132577, and m/z 285.1→193.1 for IS. Calibration plots were linear throughout the range 10-4000 ng/mL for ACT-132577 in rat plasma. Mean recovery of ACT-132577 in rat plasma ranged from 82.6% to 90.6%, matrix effect of ACT-132577 in rat plasma ranged from 101.4% to 115.2%. RSD of intra-day and inter-day precision were both less than 11%. The accuracy of the method ranged from 96.1% to 103.5%. The method was successfully applied to pharmacokinetic study of ACT-132577 after oral and intravenous administration of macitentan. PMID:26770447

  7. Liquid chromatography tandem mass spectrometry method for characterization of monoaromatic nitro-compounds in atmospheric particulate matter.

    PubMed

    Kitanovski, Zoran; Grgić, Irena; Vermeylen, Reinhilde; Claeys, Magda; Maenhaut, Willy

    2012-12-14

    Nitrogen-containing organic compounds in the atmosphere have drawn attention owing to their impact on aerosol chemistry and physics and their potential adverse effects on the biosphere. Among them, nitrocatechols and their homologs have recently been associated with biomass burning. In the present study, nitrocatechols, nitrophenols, nitroguaiacols and nitrosalicylic acids (NSAs) were simultaneously quantified for the first time by using a new analytical method based on liquid chromatography/tandem mass spectrometry, which was systematically optimized and validated. Several analyte specific issues regarding the sample preparation and chromatographic analysis were addressed in order to ensure method sensitivity, precision, and accuracy. Sample matrix effects were thoroughly investigated in order to ensure method specificity. The method was found to be sensitive with limits of detection ranging from 0.1 to 1.0 μg L(-1), and with accuracy generally between 90 and 104%. The relative standard deviations for repeatability and intermediate precision were better than 4% and 9%, respectively. The method was applied to the analysis of winter and summer PM(10) samples from the city of Ljubljana, Slovenia. Aerosol concentrations as high as 152 and 134 ng m(-3) were obtained for the major aerosol nitro-aromatics: 4-nitrocatechol (4NC) and methyl-nitrocatechols (MNCs), respectively. Up to 500-times higher concentrations of 4NC and MNCs were found in winter compared to summer aerosols. The correlation analysis for winter samples showed that 4NC, MNCs, and NSAs are strongly inter-correlated (R(2)=0.84-0.96). Significant correlations between these analytes and anhydrosugars support their proposed origin from biomass burning. The studied nitro-aromatics were found to constitute a non-negligible fraction (around 1%) of the organic carbon. PMID:23122275

  8. Analysis of Mammalian Sphingolipids by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) and Tissue Imaging Mass Spectrometry (TIMS)

    PubMed Central

    Sullards, M. Cameron; Liu, Ying; Chen, Yanfeng; Merrill, Alfred H.

    2011-01-01

    Sphingolipids are a highly diverse category of molecules that serve not only as components of biological structures but also as regulators of numerous cell functions. Because so many of the structural features of sphingolipids give rise to their biological activity, there is a need for comprehensive or “sphingolipidomic” methods for identification and quantitation of as many individual subspecies as possible. This review defines sphingolipids as a class, briefly discusses classical methods for their analysis, and focuses primarily on liquid chromatography tandem mass spectrometry (LC-MS/MS) and tissue imaging mass spectrometry (TIMS). Recently, a set of evolving and expanding methods have been developed and rigorously validated for the extraction, identification, separation, and quantitation of sphingolipids by LC-MS/MS. Quantitation of these biomolecules is made possible via the use of an internal standard cocktail. The compounds that can be readily analyzed are free long-chain (sphingoid) bases, sphingoid base 1-phosphates, and more complex species such as ceramides, ceramide 1-phosphates, sphingomyelins, mono- and di-hexosylceramides sulfatides, and novel compounds such as the 1-deoxy- and 1-(deoxymethyl)-sphingoid bases and their N-acyl-derivatives. These methods can be altered slightly to separate and quantitate isomeric species such as glucosyl/galactosylceramide. Because these techniques require the extraction of sphingolipids from their native environment, any information regarding their localization in histological slices is lost. Therefore, this review also describes methods for TIMS. This technique has been shown to be a powerful tool to determine the localization of individual molecular species of sphingolipids directly from tissue slices. PMID:21749933

  9. Ultra-performance liquid chromatography tandem mass spectrometry for the rapid simultaneous analysis of nine organophosphate esters in milk powder.

    PubMed

    Guo, Xindong; Mu, Tongna; Xian, Yanping; Luo, Donghui; Wang, Chao

    2016-04-01

    Organophosphate esters (OPEs) are common flame retardants that are used in a wide variety of products. These compounds might migrate into and pollute food products. An analytical method involving an improved approach called the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed to simultaneously measure trace levels of nine OPEs in milk powder. Separation of the nine OPEs was optimized on a reversed-phase column within 7 min. The stable isotope tri-n-butyl phosphate-d27 (TBP-d27) was used as an internal standard. This method was validated in terms of its linearity, sensitivity, precision, accuracy and matrix effects. Matrix-matched calibration curves were constructed with 1/x(2) as the weighting factor for all of the target compounds resulting in coefficients of regression lines between 0.9938 and 0.9999. The average accuracy was between 73.5% and 110.2%. Intra- and inter-assay precisions for six replicates ranged from 3.9% to 8.9% or below 11%, respectively. The limits of detection (LODs) were in the range of 0.1-0.25 μg/kg, and the limits of quantification (LOQs) were below 1.5 μg/kg. Significant matrix effects have been observed, but suppression or enhancement of the signal was compensated for by the use of an isotopically labeled internal standard. This validated method was successfully applied to determine the concentrations of the OPEs in milk powder. PMID:26593541

  10. [Determination of metabolite residues of nitrofuran antibiotics in aquatic products by liquid chromatography-tandem mass spectrometry].

    PubMed

    Wang, Chuanxian; Huang, Fan; Wang, Min; Sheng, Yonggang; Zhang, Jin; Han, Li; Song, Qing; Li, Xiaohong; Xu, Dunming; Ding, Zhuoping

    2013-03-01

    A method was developed for simultaneous qualitative and quantitative analysis of five metabolites of nitrofuran antibiotics, including 3-amino-2-oxazolidinone (AOZ), 5-morpholino-methyl-3-amino-2-oxazolidinone ( AMOZ ), semicarbazide ( SEM ), 1-aminohydantoin (AHD) and 3, 5-dinitrosalicylic acid hydrazide (DNSH) in aquatic products by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were hydrolyzed with HCl, and derivatized with 2-nitrobenzaldehyde at 37 degre C for 16 hours. The derivative solutions were adjusted to pH 7.0 -7. 5, and the analytes were extracted by ethyl acetate. The separation was based on Thermo Aquasil C18 column (150 mm x 4.6 mm, 3.01 micro m). The analytes were detected by tandem mass spectrometry with electrospray ionization source with multiple reaction monitoring (MRM) mode. The developed method showed good linear correlation between the peak area ratios of the analyte and the internal standard and the concentration of the analyte with the correlation coefficients all above 0. 99 over the dynamic range of 0.5 - 10 micro g/kg. The limits of quantitation (LOQs) of AOZ, AMOZ, SEM, AHD and DNSH were 0.5 micro g/kg. The average recoveries of all the compounds at four spiked levels of 0.5, 1.0, 2.0 and 4. 0 micro g/kg ranged from 81.3% to 100.5% with the RSDs between 3.4% and 10.0% (n =6). The method is proved to be fast and effective for simultaneous qualitative and quantitative analysis of the metabolites of the nitrofuran antibiotics in aquatic products. PMID:23785991

  11. High performance liquid chromatography-tandem mass spectrometry for the determination of bile acid concentrations in human plasma.

    PubMed

    Xiang, Xiaoqiang; Han, Yi; Neuvonen, Mikko; Laitila, Jouko; Neuvonen, Pertti J; Niemi, Mikko

    2010-01-01

    We report a sensitive and robust method to determine cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), ursodeoxycholic acid (UDCA), and their taurine- and glycine-conjugate concentrations in human plasma using liquid chromatography-tandem mass spectrometry. Activated charcoal was utilized to prepare bile acid-free plasma, which served as the biological matrix for the preparation of standard and quality control samples. Plasma sample preparation involved solid-phase extraction. A total of 16 bile acids and 5 internal standards were separated on a reverse column by gradient elution and detected by tandem mass spectrometry in negative ion mode. The calibration curve was linear for all the bile acids over a range of 0.005-5micromol/L. The extraction recoveries for all the analytes fell in the range of 88-101%. Intra-day and inter-day coefficients of variation were all below 10%. A stability test showed that all the bile acids were stable in plasma for at least 6h at room temperature, at least three freeze-thaw cycles, in the -70 degrees C or -20 degrees C freezer for 2 months, and also in the reconstitution solution at 8 degrees C for 48h. Comparison of the matrix effect of bile acid-free plasma with that of real plasma indicated that the charcoal purification procedure did not affect the properties of charcoal-purified plasma as calibration matrix. This method has been used to determine the bile acid concentrations in more than 300 plasma samples from healthy individuals. In conclusion, this method is suitable for the simultaneous quantification of individual bile acids in human plasma. PMID:19945922

  12. Quantification of a male sea lamprey pheromone in tributaries of Laurentian Great Lakes by liquid chromatography-tandem mass spectrometry

    USGS Publications Warehouse

    Xi, X.; Johnson, N.S.; Brant, C.O.; Yun, S.-S.; Chambers, K.L.; Jones, A.D.; Li, W.

    2011-01-01

    We developed an assay for measuring 7α,12α,24-trihydroxy-5a-cholan-3-one-24-sulfate (3kPZS), a mating pheromone released by male sea lampreys (Petromyzon marinus), at low picomolar concentrations in natural waters to assess the presence of invasive populations. 3kPZS was extracted from streamwater at a rate of recovery up to 90% using a single cation-exchange and reversed-phase mixed-mode cartridge, along with [2H5]3kPZS as an internal standard, and quantified using ultrahigh performance liquid chromatography-tandem mass spectrometry. The limit of detection was below 0.1 ng L–1 (210 fM), which was the lowest concentration tested. Intra- and interday coefficients of variation were between 0.3–11.6% and 4.8–9.8%, respectively, at 1 ng 3kPZS L–1 and 5 ng 3kPZS L–1. This assay was validated by repeat measurements of water samples from a stream spiked with synthesized 3kPZS to reach 4.74 ng L–1 or 0.24 ng L–1. We further verified the utility of this assay to detect spawning populations of lampreys; in the seven tributaries to the Laurentian Great Lakes sampled, 3kPZS concentrations were found to range between 0.15 and 2.85 ng L–1 during the spawning season in known sea lamprey infested segments and were not detectable in uninfested segments. The 3kPZS assay may be useful for the integrated management of sea lamprey, an invasive species in the Great Lakes where pheromone-based control and assessment techniques are desired.

  13. Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry.

    PubMed

    Faqehi, Abdullah M M; Cobice, Diego F; Naredo, Gregorio; Mak, Tracy C S; Upreti, Rita; Gibb, Fraser W; Beckett, Geoffrey J; Walker, Brian R; Homer, Natalie Z M; Andrew, Ruth

    2016-05-01

    Estrogens circulate at concentrations less than 20pg/mL in men and postmenopausal women, presenting analytical challenges. Quantitation by immunoassay is unreliable at these low concentrations. Liquid chromatography tandem mass spectrometry (LC-MS/MS) offers greater specificity and sometimes greater sensitivity, but ionization of estrogens is inefficient. Introduction of charged moieties may enhance ionization, but many such derivatives of estrogens generate non-specific product ions originating from the "reagent" group. Therefore an approach generating derivatives with product ions specific to individual estrogens was sought. Estrogens were extracted from human plasma and serum using solid phase extraction and derivatized using 2-fluoro-1-methylpyridinium-p-toluenesulfonate (FMP-TS). Electrospray in positive mode with multiple reaction monitoring using a QTrap 5500 mass spectrometer was used to quantify "FMP" derivatives of estrogens, following LC separation. Transitions for the FMP derivatives of estrone (E1) and estradiol (E2) were compound specific (m/z 362→238 and m/z 364→128, respectively). The limits of detection and quantitation were 0.2pg on-column and the method was linear from 1-400pg/sample. Measures of intra- and inter-assay variability, precision and accuracy were acceptable (<20%). The derivatives were stable over 24h at 10°C (7-9% degradation). Using this approach, E1 and E2, respectively were detected in human plasma and serum: pre-menopausal female serum (0.5mL) 135-473, 193-722pmol/L; male plasma (1mL) 25-111, 60-180pmol/L and post-menopausal female plasma (2mL), 22-78, 29-50pmol/L. Thus FMP derivatization, in conjunction with LC-MS/MS, is suitable for quantitative analysis of estrogens in low abundance in plasma and serum, offering advantages in specificity over immunoassay and existing MS techniques. PMID:26946022

  14. Determination of Synacthen(®) in dried blood spots for doping control analysis using liquid chromatography tandem mass spectrometry.

    PubMed

    Tretzel, Laura; Thomas, Andreas; Geyer, Hans; Delahaut, Philippe; Schänzer, Wilhelm; Thevis, Mario

    2015-06-01

    Dried blood spot (DBS) sampling, a technique used for taking whole blood samples dried on a filter paper, was initially reported in 1963 by Robert Guthrie. While the diagnostic analysis of metabolic disorders in newborns was the focus of investigations at that time, the number of established applications for preclinical drug development, toxicological studies, and therapeutic drug monitoring increased enormously in the last decades. As a consequence of speed, simplicity, and minimal invasiveness, DBS recommends itself as the preferential technique in sports drug testing. The present approach highlights for the first time the development of a screening assay for the analysis of the synthetic human adrenocorticotropic hormone tetracosactide hexaacetate (Synacthen(®)) in DBS using liquid chromatography tandem mass spectrometry. Highly purified sample extracts were obtained by an advanced sample preparation procedure including the addition of an internal standard (d8-tetracosactide) and immunoaffinity purification. The method's overall recovery was 27.6 %, and the assay's imprecision was calculated between 8.1 and 17.9 % for intraday and 12.9 to 20.5 % for interday measurements. Stability of the synthetic peptide in DBS was shown for at least 10 days at room temperature and presents a major benefit, since a rapid degradation in conventionally applied matrices such as urine or plasma is well known. With a limit of detection of 50 pg/mL, a detection window of several hours is expected considering reported steady-state plasma levels of 300 pg/mL after intramuscular application of Synacthen(®) Depot (1 mg). The analysis of authentic DBS samples within the scope of an administration study with 250 μg Synacthen(®) (short stimulation test) demonstrated the great potential of the developed assay to simplify the analysis of Synacthen(®) for doping control purposes. PMID:25863802

  15. Determination of four sulfated vitamin D compounds in human biological fluids by liquid chromatography-tandem mass spectrometry.

    PubMed

    Gomes, Fabio P; Shaw, P Nicholas; Hewavitharana, Amitha K

    2016-01-15

    The determination of both the water-soluble and lipid-soluble vitamin D compounds in human biological fluids is necessary to illuminate potentially significant biochemical mechanisms. The lack of analytical methods to quantify the water-soluble forms precludes studies on their role and biological functions; currently available liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods are able to determine only a single sulfated form of Vitamin D. We describe here a highly sensitive and specific LC-MS/MS method for the quantification of four sulfated forms of vitamin D: vitamins D2- and D3-sulfate (D2-S and D3-S) and 25-hydroxyvitamin D2- and D3-sulfate (25(OH)D2-S and 25(OH)D3-S). A comparative evaluation showed that the ionization efficiencies of underivatized forms in negative ion mode electrospray ionisation (ESI) are superior to those of the derivatized (using 4-phenyl-l,2,4-triazoline-3,5-dione (PTAD)) forms in positive ion mode ESI. Separation was optimised to minimise co-elution with endogenous matrix compounds, thereby reducing ion suppression/enhancement effects. Isotopically labelled analogues of each compound were used as internal standards to correct for ion suppression/enhancement effects. The method was validated and then applied for the analysis of breastmilk and human serum. The detection limits, repeatability standard deviations, and recoveries ranged from 0.20 to 0.28fmol, 2.8 to 10.2%, and 81.1 to 102%, respectively. PMID:26708628

  16. Toxin Profile of Gymnodinium catenatum (Dinophyceae) from the Portuguese Coast, as Determined by Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Costa, Pedro R.; Robertson, Alison; Quilliam, Michael A.

    2015-01-01

    The marine dinoflagellate Gymnodinium catenatum has been associated with paralytic shellfish poisoning (PSP) outbreaks in Portuguese waters for many years. PSP syndrome is caused by consumption of seafood contaminated with paralytic shellfish toxins (PSTs), a suite of potent neurotoxins. Gymnodinium catenatum was frequently reported along the Portuguese coast throughout the late 1980s and early 1990s, but was absent between 1995 and 2005. Since this time, G. catenatum blooms have been recurrent, causing contamination of fishery resources along the Atlantic coast of Portugal. The aim of this study was to evaluate the toxin profile of G. catenatum isolated from the Portuguese coast before and after the 10-year hiatus to determine changes and potential impacts for the region. Hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) was utilized to determine the presence of any known and emerging PSTs in sample extracts. Several PST derivatives were identified, including the N-sulfocarbamoyl analogues (C1–4), gonyautoxin 5 (GTX5), gonyautoxin 6 (GTX6), and decarbamoyl derivatives, decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNeo) and decarbamoyl gonyautoxin 3 (dcGTX3). In addition, three known hydroxy benzoate derivatives, G. catenatum toxin 1 (GC1), GC2 and GC3, were confirmed in cultured and wild strains of G. catenatum. Moreover, two presumed N-hydroxylated analogues of GC2 and GC3, designated GC5 and GC6, are reported. This work contributes to our understanding of the toxigenicity of G. catenatum in the coastal waters of Portugal and provides valuable information on emerging PST classes that may be relevant for routine monitoring programs tasked with the prevention and control of marine toxins in fish and shellfish. PMID:25871287

  17. Quantitative determination of ɛ-N-carboxymethyl-L-lysine in human plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    Kuang, Liqing; Jing, Zhiqiang; Wang, Jing; Ma, Liyuan; Liu, Xiaoqiang; Yang, Jin

    2014-03-01

    ɛ-N-carboxymethyl-L-lysine (CML) is a stable chemical modification of protein lysine residues resulting from glycation and oxidation reactions and a potential biomarker of oxidative stress caused by sugar and lipid oxidation. In this study, a rapid, simple and sensitive method based on liquid chromatography-tandem spectrometry (LC-MS/MS) for the determination of CML in human plasma has been developed and validated. Sample preparation involved protein precipitation using trichloroacetic acid after addition of deuterated CML as internal standard. Chromatography was performed on an amino column by gradient-elution with a mobile phase containing acetonitrile:ultrapure water (80:20, v/v). CML and CML-d2 were detected by multiple reaction monitoring mode with ion pairs 205.0/130.1 and 207.2/84.1 respectively. The assay was linear in the range 10-1000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL and recovery >90%. Assay validation showed that inter- and intra-day precision and accuracy were satisfactory. The method was applied to compare plasma CML levels in healthy Chinese subjects and patients with diabetes and uremia. In healthy subjects CML concentration (mean±SD) was 16.6±7.8 ng/mL. CML level in diabetic patients was not significantly different from healthy subjects whereas the level in patients with uremia was significantly higher than both healthy subjects and diabetic patients (P<0.001). The method will be useful to assess the value of CML as a biomarker of diabetic vascular complications resulting from elevated oxidative stress. PMID:24317023

  18. Highly sensitive and selective measurement of underivatized methylmalonic acid in serum and plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    Yuan, Chao; Gabler, Jessica; El-Khoury, Joe M; Spatholt, Regina; Wang, Sihe

    2012-07-01

    Methylmalonic acid (MMA) is a functional biomarker of vitamin B12 deficiency. Measurement of plasma MMA is challenging due to its small molecular weight and hydrophilic nature. Several liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods have been developed for measuring plasma MMA. However, these methods involve lengthy sample preparation, long chromatographic run time, inadequate sensitivity, or interference from succinic acid (SA). Here we report a novel LC-MS/MS method for quantitation of underivatized MMA in serum or heparinized plasma with high sensitivity and selectivity. Sample preparation involved only strong anion exchange solid phase extraction. The extract was purified by online turbulent flow and analyzed on an Organic Acids column. MS/MS analysis was performed in negative electrospray mode, and the analytical time was 6 min. The use of ion ratio confirmation in combination with chromatographic resolution from SA greatly enhanced the selectivity. No interference was observed. This method was linear from 26.2 to 26,010.0 nM with an accuracy of 98-111 %. Total coefficient of variation was less than 4.6 % for three concentration levels tested. Comparison with a reference laboratory LC-MS/MS method using leftover patient serum specimens (n = 48) showed a mean bias of -2.3 nM (-0.61 %) with a Deming regression slope of 1.016, intercept of -6.6 nM, standard error of estimate of 25.3 nM, and a correlation coefficient of 0.9945. In conclusion, this LC-MS/MS method offers highly sensitive and selective quantitation of MMA in serum and plasma with simple sample preparation. PMID:22618327

  19. Pediatric Reference Intervals for Free Thyroxine and Free Triiodothyronine by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    La’ulu, Sonia L.; Rasmussen, Kyle J.; Straseski, Joely A.

    2016-01-01

    Objective: Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose thyroid disease in pediatric patients, reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy patients is particularly challenging for pediatric populations. The objective of this study was to determine non-parametric RIs for free thyroxine (fT4) and free triiodothyronine (fT3) using equilibrium dialysis-high performance liquid chromatography-tandem mass spectrometry with over 2200 healthy children 6 months-17 years of age. Methods: Subjects were negative for both thyroglobulin and thyroid peroxidase autoantibodies and had normal thyrotropin concentrations. The study included 2213 children (1129 boys and 1084 girls), with at least 120 subjects (average of 125) from each year of life, except for the 6 month to 1 year age group (n=96). Results: Non-parametric RIs (95th percentile) for fT4 were: 18.0-34.7 pmol/L (boys and girls, 6 months-6 years) and 14.2-25.7 pmol/L (boys and girls, 7-17 years). RIs for fT3 were: 5.8-13.1 pmol/L (girls, 6 months-6 years); 5.7-11.8 pmol/L (boys, 6 months-6 years); 5.7-10.0 pmol/L (boys and girls, 7-12 years); 4.5-8.6 pmol/L (girls, 13-17 years); and 5.2-9.4 pmol/L (boys, 13-17 years). Conclusion: Numerous significant differences were observed between pediatric age groups and previously established adult ranges. This emphasizes the need for well-characterized RIs for thyroid hormones in the pediatric population. PMID:26758817

  20. Quantification of vincristine and its major metabolite in human plasma by high-performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Dennison, Jennifer B; Renbarger, Jamie L; Walterhouse, David O; Jones, David R; Hall, Stephen D

    2008-06-01

    An analytical method using electrospray ionization and high-performance liquid chromatography/tandem mass spectrometry (LC/ESI-MS/MS) was developed to quantify vincristine and M1, the CYP3A-mediated metabolite of vincristine, in human plasma. Vinblastine (internal standard), vincristine, and M1 in plasma were extracted in methylene chloride after acidification with TCAA. The analytes were separated on an Inertsil ODS-3 C18 column (2.1 x 150 mm) with a 5-mum particle size using a gradient elution with a run time of 20 min. The initial mobile phase composition was 0.2% formic acid/water (80:20, v/v) with a final composition of 0.2% formic acid/water (20:80, v/v). Detection was accomplished with multiple reaction monitoring for vinblastine (m/z 406.3--> 271.7), vincristine (m/z 413.2--> 362.2), and M1 (m/z 397.3 --> 376.2). At three concentrations of vincristine and M1, the inter-day and intra-day accuracy and precision were within the acceptable limits for validation (106.8 +/- 9.6% for intra-day, n = 5 each concentration; 90.9 +/- 10.9% for inter-day, n = 4 each concentration). For both vincristine and M1, the concentration limits of quantification and detection were 12 pg/mL and 6 pg/mL, respectively. Stability studies indicated that 80% of M1 degraded in plasma after 15 hours at room temperature (n = 3, high and low QC concentrations). Therefore, short plasma processing times (<30 min) are recommended. The assay was used successfully to quantify vincristine and M1 in pediatric plasma samples up to 24 hours after vincristine administration. Vincristine and M1 concentrations were within the limits of quantification for all patient plasma samples. PMID:18520608

  1. Evaluation of different cleanup sorbents for multiresidue pesticide analysis in fatty vegetable matrices by liquid chromatography tandem mass spectrometry.

    PubMed

    López-Blanco, Rafael; Nortes-Méndez, Rocío; Robles-Molina, José; Moreno-González, David; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

    2016-07-22

    In this article we have evaluated the performance of different sorbents for the cleanup step in multiresidue pesticide analysis in fatty vegetable matrices using QuEChERS methodology. The three different matrices tested (olive oil, olives and avocado) were partitioned using acetonitrile prior to cleanup step. Afterwards, the supernatant was purified using different sorbents: C18+PSA (primary secondary amine), Z-Sep(+) (zirconium oxide and C18 dual bonded to silica), Z-Sep (zirconium oxide bonded to silica) and a novel sorbent Enhanced Matrix Removal-Lipid (EMR) whose composition has not been disclosed. The different cleanup strategies were compared for a group of 67 representative pesticides in terms of recovery rates, matrix effects, extract cleanliness and precision using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The best extraction efficiencies in olive oil matrix were obtained using EMR, while the results for olives and avocado were pretty similar amongst the different sorbents with an overall lower performance in terms of matrix effects and recovery rates compared to olive oil data, particularly in olives due to the higher complexity and concentration of coextracted species. On the other hand, the average reproducibility was clearly better when EMR sorbent was employed in all selected matrices for most pesticides (RSD<10% for 45, 52, and 56 pesticides in avocado, olives and olive oil respectively). The best results in terms of matrix effects were also obtained with EMR; with signal suppression lower than 20% for 79%, 16% and 51% of pesticides tested in olive oil, olives and avocado respectively. Using EMR as cleanup sorbent, limits of quantitation using UHPLC-MS/MS, ranged from 0.10 to 90μgkg(-1), allowing their determination at the low concentration levels demanded by current olive oil regulations in most cases. PMID:27328883

  2. Quantification of anthocyanins and flavonols in milk-based food products by ultra performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Nagy, Kornél; Redeuil, Karine; Bertholet, Raymond; Steiling, Heike; Kussmann, Martin

    2009-08-01

    The present article describes the development and validation of an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the comprehensive quantification of anthocyanin and flavonol constituents of milk-based food products. Protein precipitation by acidified methanol and ultrafiltration was utilized as sample preparation to preserve overall polyphenol composition but to eliminate milk proteins in order to comply with UPLC. Reversed-phase chromatography was optimized to achieve separation of 27 analytes in 10 min in order to reduce suppression effects, achieve a wide dynamic range, and most importantly, to resolve isomeric compounds. Positive-ion electrospray mass spectrometric detection and fragmentation of analytes was optimized, final transitions were selected for maximized selectivity, reliable quantification, and reduction of false positives. The quantitative performance of the method was validated, the main features include (1) range of lower limits of detection 0.3-30 ng/mL for glycosylated analytes, 10-300 ng/mL for aglycones, (2) lower limits of quantification 1-100 ng/mL for glycosylated analytes, 30-1,000 ng/mL for aglycones, (3) averaged intraday precision 9%, (4) calibrated range 2-180,000 ng/mL for glycosylated analytes, 60-600,000 ng/mL for aglycones, and (5) averaged accuracy 101%. Applications for yogurt and ice cream products are given. The presented data suggest that this method will help to better characterize the polyphenol composition of milk-based food products for quality control, for assessment of dietary intake, and for polyphenol bioavailability/bioefficacy studies. PMID:20337399

  3. Patterns of free (unconjugated) buprenorphine, norbuprenorphine, and their glucuronides in urine using liquid chromatography-tandem mass spectrometry.

    PubMed

    McMillin, Gwendolyn A; Davis, Rebecka; Carlisle, Heidi; Clark, Chantry; Marin, Stephanie J; Moody, David E

    2012-03-01

    Patterns of buprenorphine and metabolites were examined in 1946 positive urine samples analyzed by liquid chromatography-tandem mass spectrometry for free (unconjugated) buprenorphine and norbuprenorphine (quantitative, 2 to 1000 ng/mL) and buprenorphine-glucuronide (B3G) and norbuprenorphine-glucuronide (N3G) (semi-quantitative, 5 to 1000 ng/mL). Two distribution patterns predominated with 49.1% positive for norbuprenorphine, B3G, and N3G and 41.6% positive for buprenorphine, norbuprenorphine, B3G, and N3G. Buprenorphine, positive in 45.5% of samples, was mostly < 5 ng/mL (median 6.1 ng/mL), but 9.8% were > 1000 ng/mL. Norbuprenorphine, B3G, and N3G had semi-Gaussian distributions with medians of 64.7, 108, and 432 ng/mL, respectively. With buprenorphine < 100 ng/mL (767 samples) or ≥ 100 ng/mL (19 quantifiable samples), the respective median metabolic ratios (free norbuprenorphine/free buprenorphine) were 25.0 and 0.15. In 12 retested "> 1000 ng/mL" buprenorphine samples, free buprenorphine was 4160 to 39,400 ng/mL and free naloxone 2140 to 9560 ng/mL. In 87 subsequent samples with buprenorphine < 20 ng/mL, naloxone concentrations were < 50 ng/mL. Concentrations of buprenorphine > 100 ng/mL (particularly with low metabolite concentrations) are suspect of urine adulteration with medication (4% in the database) that can be checked in most cases by concurrent analysis for naloxone. PMID:22337776

  4. Simultaneous analysis of buprenorphine, methadone, cocaine, opiates and nicotine metabolites in sweat by liquid chromatography tandem mass spectrometry.

    PubMed

    Concheiro, Marta; Shakleya, Diaa M; Huestis, Marilyn A

    2011-04-01

    A liquid chromatography tandem mass spectrometry method for buprenorphine (BUP), norbuprenorphine (NBUP), methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylecgonine, ecgonine methyl ester (EME), morphine, codeine, 6-acetylmorphine, heroin, 6-acetylcodeine, cotinine, and trans-3'-hydroxycotinine quantification in sweat was developed and comprehensively validated. Sweat patches were mixed with 6 mL acetate buffer at pH 4.5, and supernatant extracted with Strata-XC-cartridges. Reverse-phase separation was achieved with a gradient mobile phase of 0.1% formic acid and acetonitrile in 15 min. Quantification was achieved by multiple reaction monitoring of two transitions per compound. The assay was a linear 1-1,000 ng/patch, except EME 5-1,000 ng/patch. Intra-, inter-day and total imprecision were <10.1%CV, analytical recovery 87.2-107.7%, extraction efficiency 35.3-160.9%, and process efficiency 25.5-91.7%. Ion suppression was detected for EME (-63.3%) and EDDP (-60.4%), and enhancement for NBUP (42.6%). Deuterated internal standards compensated for these effects. No carryover was detected, and all analytes were stable for 24 h at 22 °C, 72 h at 4 °C, and after three freeze/thaw cycles. The method was applied to weekly sweat patches from an opioid-dependent BUP-maintained pregnant woman; 75.0% of sweat patches were positive for BUP, 93.8% for cocaine, 37.5% for opiates, 6.3% for methadone and all for tobacco biomarkers. This method permits a fast and simultaneous quantification of 14 drugs and metabolites in sweat patches, with good selectivity and sensitivity. PMID:21125263

  5. Pharmacokinetics in rats and tissue distribution in mouse of magnoflorine by ultra performance liquid chromatography-tandem mass spectrometry

    PubMed Central

    Bao, Shihui; Geng, Peiwu; Wang, Shuanghu; Zhou, Yunfang; Hu, Lufeng; Yang, Xuezhi

    2015-01-01

    Magnoflorine is one of the most widespread aporphine alkaloids. In this work, a sensitive and selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of magnoflorine in rat plasma and mouse tissue have been developed and validated. After addition of nuciferine as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used for samples treatment. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm×100 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 342.8→298.2 for magnoflorine and m/z 296.0→265.1 for IS. Calibration plots were linear throughout the range 2-2000 ng/mL for magnoflorine in rat plasma and tissue. Mean recoveries of magnoflorine in rat plasma were better than 83.0%. RSD of intra-day and inter-day precision were both less than 9%. The accuracy of the method was between 95.5% and 107.5%. The method was successfully applied to pharmacokinetics and tissue distribution study of magnoflorine. The absolute bioavailability of magnoflorine was reported as 22.6%. The magnoflorine underwent a rapid and wide distribution to tissues; the level of magnoflorine in liver is highest, then followed by heart, spleen and lung. Based on tissue distribution data, a back-propagation artificial neural network (BP-ANN) method was developed and it could be used to predict the concentrations of magnoflorine in tissues. PMID:26884929

  6. Determination of steroids and their intact glucuronide conjugates in mouse brain by capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Jäntti, Sirkku E; Tammimäki, Anne; Raattamaa, Helena; Piepponen, Petteri; Kostiainen, Risto; Ketola, Raimo A

    2010-04-15

    A method for the identification and quantitation of 10 brain steroids and their 2 sulfate and 9 glucuronide conjugates in mouse brain tissues was developed and validated. The method includes the extraction of homogenized brain by solid-phase extraction and the analysis of the extracts by capillary liquid chromatography-tandem mass spectrometry. The main advantage of the method is that steroid conjugates in brain can be analyzed as intact compounds, without derivatization, hydrolysis, or complex sample preparation procedures; thus, the true identity of the conjugates can be confirmed with tandem mass spectrometric detection. The method was validated to show its linearity (r > 0.998) and precision (<9%). The limits of detection in solution were from 6 to 80 pmol/L for steroid glucuronides, from 13 to 32 pmol/L for steroid sulfates, and from 26 pmol/L to 2.2 nmol/L for native steroids. The recovery of internal standards was 95% for d3-testosterone glucuronide and 69% for d4-allopregnanolone from spiked mouse hippocampus. Brain tissue samples from mouse hippocampus and hypothalamus were analyzed using the new method. Several steroids and glucuronides were identified and quantified from the mouse brain at concentration levels of 0.2-58 ng/g. The concentrations of steroid glucuronides were significant compared to those of their aglycons, indicating that glucuronidation might be an important metabolic pathway for some steroids in the mouse brain. The method developed in this study provides for the first time direct quantitative determination of steroids and their glucuronides and sulfates in brain without hydrolysis and, therefore, creates the possibility to study in detail the role of steroid glucuronidation and sulfation in the brain. PMID:20345173

  7. Simultaneous quantification of dabrafenib and trametinib in human plasma using high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Nijenhuis, C M; Haverkate, H; Rosing, H; Schellens, J H M; Beijnen, J H

    2016-06-01

    Dabrafenib (Tafinlar(®)) and trametinib (Mekinist(®)) are registered for the treatment of patients with BRAF V600 mutation positive unresectable or metastatic melanoma. To support therapeutic drug monitoring (TDM) and clinical pharmacological trials, an assay to simultaneously quantify dabrafenib and trametinib in human plasma using liquid chromatography tandem mass spectrometry was developed and validated. Human plasma samples were collected on an outpatient base and stored at nominally -20°C. Analytes and internal standards (stable isotope labeled compounds) were extracted with TBME. After snap freezing the samples in a dry ice-ethanol bath, the organic layer was transferred to a clean tube and evaporated under a gentle stream of nitrogen gas. The dry extract was then reconstituted with 100μL acetonitrile and 5μL of the final extract was injected and separated on a C18 column with gradient elution, and analyzed with triple quadrupole mass spectrometry in positive-ion mode. The validated assay ranges from 50 to 5000ng/mL for dabrafenib and 0.5-50ng/mL for trametinib were linear, and correlation coefficient (r(2)) of 0.996 or better. At all concentrations of both analytes the biases were within ±15% of the nominal concentrations and precisions were ≤15%. All results were within the acceptance criteria of the latest US FDA guidance and EMA guidelines on method validation. Dabrafenib was found to degrade under the influence of light in different organic solvents and at least seven degradation products were detected. In conclusion, the described method to simultaneously quantify dabrafenib and trametinib in human plasma was successfully validated and applied for therapeutic drug monitoring in cancer patients treated with dabrafenib and trametinib. PMID:27058232

  8. [Determination of eight pesticide residues in tea by liquid chromatography-tandem mass spectrometry and its uncertainty evaluation].

    PubMed

    Hu, Beizhen; Cai, Haijiang; Song, Weihua

    2012-09-01

    A method was developed for the determination of eight pesticide residues (fipronil, imidacloprid, acetamiprid, buprofezin, triadimefon, triadimenol, profenofos, pyridaben) in tea by liquid chromatography-tandem mass spectrometry. The sample was extracted by accelerated solvent extraction with acetone-dichloromethane (1:1, v/v) as solvent, and the extract was then cleaned-up with a Carb/NH2 solid phase extraction (SPE) column. The separation was performed on a Hypersil Gold C, column (150 mm x 2. 1 mm, 5 microm) and with the gradient elution of acetonitrile and 0. 1% formic acid. The eight pesticides were determined in the modes of electrospray ionization (ESI) and multiple reaction monitoring (MRM). The analytes were quantified by matrix-matched internal standard method for imidacloprid and acetamiprid, by matrix-matched external standard method for the other pesticides. The calibration curves showed good linearity in 1 - 100 microg/L for fipronil, and in 5 -200 microg/L for the other pesticides. The limits of quantification (LOQs, S/N> 10) were 2 p.g/kg for fipronil and 10 microg/kg for the other pesticides. The average recoveries ranged from 75. 5% to 115.0% with the relative standard deviations of 2.7% - 7.7% at the spiked levels of 2, 5, 50 microg/kg for fipronil and 10, 50, 100 microg/kg for the other pesticides. The uncertainty evaluation for the results was carried out according to JJF 1059-1999 "Evaluation and Expression of Uncertainty in Measurement". Items constituting measurement uncertainty involved standard solution, weighing of sample, sample pre-treatment, and the measurement repeatability of the equipment were evaluated. The results showed that the measurement uncertainty is mainly due to sample pre-treatment, standard curves and measurement repeatability of the equipment. The method developed is suitable for the conformation and quantification of the pesticides in tea. PMID:23285969

  9. Comprehensive multi-residue method for the target analysis of pesticides in crops using liquid chromatography-tandem mass spectrometry.

    PubMed

    Hiemstra, Maurice; de Kok, André

    2007-06-22

    A liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) multi-residue method for the simultaneous target analysis of a wide range of pesticides and metabolites in fruit, vegetables and cereals has been developed. Gradient elution has been used in conjunction with positive mode electrospray ionization tandem mass spectrometry to detect up to 171 pesticides and/or metabolites in different crop matrices using a single chromatographic run. Pesticide residues were extracted/partitioned from the samples with acetone/dichloromethane/light petroleum. The analytical performance was demonstrated by the analysis of extracts from lettuce, orange, apple, cabbage, grape and wheat flour, spiked at three concentration levels ranging from 0.01 to 0.10 mg/kg for each pesticide and/or metabolite. In general, recoveries ranging from 70 to 110%, with relative standard deviations better than 15%, were obtained. The recovery and repeatability data are in good accordance with EU guidelines for pesticide residue analysis. The limit of quantification for all targeted pesticides and metabolites tested was 0.01 mg/kg. The selectivity and robustness of the LC-MS/MS method was demonstrated by a 1-year comparison of its analytical results with those obtained from our validated GC and LC multi-residue methods applied to more than 3500 routine samples. The validated LC-MS/MS method has been implemented in our analytical scheme since 2004, replacing four of the conventional detection methods, i.e. GC-flame-photometric detection (acephate, methamidophos, etc.), GC-nitrogen-phosphorus detection, LC-UV detection (carbendazim, thiabendazole, imazalil and prochloraz) and LC-fluorescence detection (N-methylcarbamate pesticides). During a 3-year period, the LC-MS/MS method has been applied to the analyses of more than 12,000 samples. PMID:17442324

  10. Bio-analysis of forensically relevant drugs in alternative matrices by liquid chromatography-tandem mass spectrometry.

    PubMed

    Laloup, M; Samyn, N; Maes, V

    2008-01-01

    Cannabis is the most frequently detected illicit drug in the Western world, e.g. in cases of driving under the influence of drugs (DUID), whereas benzodiazepines comprise the most abused licit drugs and have been linked with drug-facilitated sexual assault cases (DFSA). In recent years, remarkable advances in sensitive analytical techniques have enabled the analysis of drugs in alternative matrices such as oral fluid and hair. These specimens allow easy, non-invasive sampling, which can be achieved under close supervision to prevent adulteration or substitution of the samples. The volume is often limited and to achieve the required analytical sensitivity, liquid chromatography-tandem mass spectrometry (LC-MS-MS) methods for the detection of cannabis and benzodiazepines in oral fluid and hair were developed. After validation, these methods were applied to genuine samples to assess: (a) the validity of oral fluid to detect recent cannabis consumption, (b) the Dräger Drug Test as an on-site oral fluid test, and (c) the applicability of hair testing in forensic cases. The latter led to new insights into metabolic conversions between benzodiazepines; this knowledge may avoid potentially erratic conclusions regarding DFSA. Finally, benzodiazepines are also frequently encountered in post-mortem cases. An LCMS-MS method to detect benzodiazepines in larvae and puparia of insects rearing on corpses was developed and validated. In conclusion, this research aimed at combining the usefulness of alternative matrices with the analytical power of LC-MS-MS. Final outcome is a number of sensitive and validated methods ready for use in routine analysis. PMID:19725394

  11. Sensitive method for detection of cocaine and associated analytes by liquid chromatography-tandem mass spectrometry in urine.

    PubMed

    Langman, Loralie J; Bjergum, Matthew W; Williamson, Christopher L; Crow, Frank W

    2009-10-01

    Cocaine (COC) is a potent CNS stimulant that is metabolized to benzoylecgonine (BE) and further metabolized to minor metabolites such as m-hydroxybenzoylecgonine (m-HOBE). COC is also metabolized to norcocaine (NC). Cocaethylene (CE) is formed when cocaine and ethyl alcohol are used simultaneously. Anhydroecgonine methyl ester (AEME) is a unique marker following smoked cocaine, and anhydroecgonine ethyl ester (AEEE) is found in cocaine smokers who also use ethyl alcohol. We developed a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the detection and quantitation of COC, BE, NC, CE, m-HOBE, AEME, and AEEE in urine. Two hundred samples previously analyzed by gas chromatography (GC) coupled with MS were extracted using solid-phase extraction. Chromatographic separation was achieved using a gradient consisting of mobile phase A [20 mM ammonium formate (pH 2.7)] and mobile phase B (methanol/acetonitrile, 50:50), an XDB-C(8) (50 x 2.1 mm, 1.8 microm) column and a flow rate of 270 microL/min. Concentrations were calculated by comparing the peak-area with the internal standard and plotted against a standard curve. The assay displayed linearity from 1.0 to 100 ng/mL. Within- and between-run coefficients of variation were < 10% throughout the linear range. A method comparison between GC-MS and LC-MS-MS showed good correlation for COC (r(2) = 0.982) and BE (r(2) = 0.955). We report here on a sensitive method to identify clinically and forensically relevant cocaine and associated analytes at concentrations as low as 1.0 ng/mL. PMID:19874651

  12. A comparison between two different automated total 25-hydroxyvitamin D immunoassay methods using liquid chromatography-tandem mass spectrometry

    PubMed Central

    Kocak, Fatma Emel; Ozturk, Bahadir; Isiklar, Ozben Ozden; Genc, Ozlem; Unlu, Ali; Altuntas, Irfan

    2015-01-01

    Introduction Total 25-hydroxyvitamin D [25(OH)D] is the most reliable indicator of vitamin D status. In this study, we compared two automated immunoassay methods, the Abbott Architect 25-OH Vitamin D assay and the Roche Cobas Vitamin D total assay, with the liquid chromatography-tandem mass spectrometry (LC-MS/MS). Materials and methods One hundred venous blood samples were randomly selected from routine vitamin D tests. Two of the serum aliquots were analyzed at the Abbott Architect i2000 and the Roche Cobas 6000’s module e601 in our laboratory within the same day. The other serum aliquots were analyzed at the LC-MS/MS in different laboratory. Passing-Bablok regression analysis and Bland-Altman plot were used to compare methods. Inter-rater agreement was analyzed using kappa (κ) analysis. Results The Roche assay showed acceptable agreement with the LC-MS/MS based on Passing-Bablok analysis (intercept: -5.23 nmol/L, 95% CI: -8.73 to 0.19; slope: 0.97, 95% CI: 0.77 to 1.15). The Abbott assay showed proportional (slope: 0.77, 95% CI: 0.67 to 0.85) and constant differences (intercept: 17.08 nmol/L; 95% CI: 12.98 to 21.39). A mean bias of 15.1% was observed for the Abbott and a mean bias of -14.1% was observed for the Roche based on the Bland-Altman plots. We found strong to nearly perfect agreement in vitamin D status between the immunoassays and LC-MS/MS. (κ: 0.83 for Abbott, κ: 0.93 for Roche) using kappa analysis. Conclusion Both immunoassays demonstrated acceptable performance, but the Roche Cobas assay demonstrated better performance than the Abbott Architect in the studied samples. PMID:26526462

  13. Simple and rapid screening procedure for 143 new psychoactive substances by liquid chromatography-tandem mass spectrometry.

    PubMed

    Adamowicz, Piotr; Tokarczyk, Bogdan

    2016-07-01

    In recent years, many new psychoactive substances (NPS) from several drug classes have appeared on the drug market. These substances, also known as 'legal highs', belong to different chemical classes. Despite the increasing number of NPS, there are few comprehensive screening methods for their detection in biological specimens. In this context, the purpose of this study was to develop a fast and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening procedure for NPS in blood. The elaborated method allows the simultaneous screening of 143 compounds from different groups (number of compounds): cathinones (36), phenethylamines (26), tryptamines (18), piperazines (9), piperidines (2), synthetic cannabinoids (34), arylalkylamines (7), arylcyclohexylamines (3), aminoindanes (2), and other drugs (6). Blood samples (0.2 mL) were precipitated with acetonitrile (0.6 mL). The separation was achieved with gradient mobile phase of 0.1% formic acid in acetonitrile and 0.1% formic acid in water in 14 min. Detection of all compounds was based on multiple reaction monitoring (MRM) transitions. The total number of transitions monitored in dynamic mode was 432. The whole procedure was rapid and simple. The limits of detection (LODs) estimated for 104 compounds were in the range 0.01-3.09 ng/mL. The extraction recoveries determined for 32 compounds were from 1.8 to 133%. The procedure was successfully applied to the analysis of forensic blood samples in routine casework. The developed method should have wide applicability for rapid screening of new drugs of abuse in forensic or clinical samples. The procedure can be easily expanded for more substances. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25976069

  14. [Rapid analysis of 28 primary aromatic amines in aqueous food simulants by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Xiao, Xiaofeng; Wang, Jianling; Yang, Juanjuan; Liu, Tingfei; Chen, Tong; He, Jun; Deng, Hongyi; Gao, Qiyan

    2013-01-01

    A novel method for rapid analysis of the migration amounts of 28 primary aromatic amines (PAAs) in aqueous food simulants (10% ethanol, 30 g/L acetic acid and 20% ethanol aqueous solution) was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After the migration test, the soaking solution was cooled down from 100 degrees C, vortexed, filtered through a hydrophilic polytetrafluoroethylene filter with a disposable syringe, and then the filtrate was analyzed by HPLC-MS/MS. A Zorbax SB-Phenyl column (250 mm x 4.6 mm, 5 microm) was selected for chromatography. The mobile phase consisted of water and 0.1% formic acid-25% acetonitrile-methanol solution with gradient elution. The 28 PAAs in aqueous food simulants were detected by tandem mass spectrometer operated in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode. The limits of quantification for the 28 PAAs were between 0.002 microg/L and 10 microg/L. The linearity of the method was good with correlation coefficients (r2) greater than 0.995 over the concentration range from 5 microg/L or 10 microg/L to 100 microg/L. The average recoveries of the 28 PAAs were between 76.6% and 114% with the relative standard deviations between 1.53% and 8.97% at the levels of 10, 20, and 40 microg/L. The method shows rapid pretreatment, the lower limits of quantification, good recoveries and accuracies, and meets the requirement of European Union (EU) No 10/2011 regulation for the specific migration of PAAs. The method has been applied to analyze the 28 PAAs in different aqueous food simulants from the migration test of 30 batches of food contact material samples exported to EU. PMID:23667988

  15. Ultrasensitive quantification of serum estrogens in postmenopausal women and older men by liquid chromatography-tandem mass spectrometry

    PubMed Central

    Wang, Qingqing; Rangiah, Kannan; Mesaros, Clementina; Snyder, Nathaniel W.; Vachani, Anil; Song, Haifeng; Blair, Ian A.

    2015-01-01

    An ultrasensitive stable isotope dilution liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for multiplexed quantitative analysis of six unconjugated and conjugated estrogens in human serum. The quantification utilized a new derivatization procedure, which formed analytes as pre-ionized N-methyl pyridinium-3-sulfonyl (NMPS) derivatives. This method required only 0.1 mL of human serum, yet was capable of simultaneously quantifying six estrogens within 20 min. The lower limit of quantitation (LLOQ) for estradiol (E2), 16α-hydroxy (OH)-E2, 4-methoxy (MeO)-E2 and 2-MeO-E2 was 1 fg on column, and was 10 fg on column for 4-OH-E2 and 2-OH-E2. All analytes demonstrated a linear response from 0.5 to 200 pg/mL (5–2000 pg/mL for 4-OH-E2 and 2-OH-E2). Using this validated method, the estrogen levels in human serum samples from 20 female patients and 20 male patients were analyzed and compared. The levels found for unconjugated serum E2 from postmenopausal women (mean 2.7 pg/mL) were very similar to those obtained by highly sensitive gas chromatography-mass spectrometry (GC-MS) methodology. However, the level obtained in serum from older men (mean 9.5 pg/mL) was lower than has been reported previously by both GC-MS and LC-MS procedures. The total (unconjugated + conjugated) 4-MeO-E2 levels were significantly higher in female samples compared with males (p<0.05). The enhanced sensitivity offered by the present method will allow for a more specific analysis of estrogens and their metabolites. Our observations might suggest that the level of total 4-MeO-E2 could be a potential biomarker for breast cancer cases. PMID:25637677

  16. Determination of propofol glucuronide from hair sample by using mixed mode anion exchange cartridge and liquid chromatography tandem mass spectrometry.

    PubMed

    Kwak, Jae-Hwan; Kim, Hye Kyung; Choe, Sanggil; In, Sangwhan; Pyo, Jae Sung

    2016-03-15

    The main objective of this study was to develop and validate a simpler and less time consuming analytical method for determination of propofol glucuronide from hair sample, by using mixed mode anion exchange cartridge and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The study uses propofol glucuronide, a major metabolite of propofol, as a marker for propofol abuse. The hair sample was digested in sodium hydroxide solution and loaded in mixed-mode anion cartridge for solid phase extraction. Water and ethyl acetate were used as washing solvents to remove interfering substances from the hair sample. Consequently, 2% formic acid in ethyl acetate was employed to elute propofol glucuronide from the sorbent of mixed-mode anion cartridge, and analyzed by LC-MS/MS. The method validation parameters such as selectivity, specificity, LOD, LLOQ, accuracy, precision, recovery, and matrix effect were also tested. The linearity of calibration curves showed good correlation, with correlation coefficient 0.998. The LOD and LLOQ of the propofol glucuronide were 0.2 pg/mg and 0.5 pg/mg, respectively. The intra and inter-day precision and accuracy were acceptable within 15%. The mean values of recovery and matrix effect were in the range of 91.7-98.7% and 87.5-90.3%, respectively, signifying that the sample preparation, washing and extraction procedure were efficient, and there was low significant hair matrix effect for the extraction of propofol glucuronide from hair sample on the mixed mode anion cartridge. To evaluate the suitability of method, the hair of propofol administered rat was successfully analyzed with this method. PMID:26946424

  17. Liquid chromatography-tandem mass spectrometry analysis of human adrenal vein corticosteroids before and after ACTH stimulation

    PubMed Central

    Nakamura, Yasuhiro; Rege, Juilee; Satoh, Fumitoshi; Morimoto, Ryo; Kennedy, Michael R; Ahlem, Clarence N; Honma, Seijiro; Sasano, Hironobu; Rainey, William E

    2014-01-01

    Context Although steroid hormones produced by the adrenal gland play critical roles in human physiology, a detailed quantitative analysis of the steroid products has not been reported. The current study uses a single methodology (liquid chromatography-tandem mass spectrometry, LC-MS/MS) to quantify ten corticosteroids in adrenal vein (AV) samples pre and post adrenocorticotropic hormone (ACTH) stimulation. Design/methods Three men and six women with a diagnosis of an adrenal aldosterone-producing adenoma (APA) were included in the study. Serum was collected from the iliac vein (IV) and the adrenal vein (AV) contralateral to the diseased adrenal. Samples were collected, before and after administration of ACTH. LC-MS/MS was then used to quantify serum concentrations of unconjugated corticosteroids and their precursors. Results Prior to ACTH stimulation the four most abundant steroids in AV were cortisol (90%), cortisone (4%), corticosterone (3%) and 11-deoxycortisol (0.8%). Post ACTH administration, cortisol remained the major adrenal product (79%), however, corticosterone became the second most abundantly produced adrenal steroid (11%) followed by pregnenolone (2.5%) and 17α-hydroxypregnenolone (2%). ACTH significantly increased the absolute adrenal output of all ten corticosteroids measured (P<0.05). The four largest post ACTH increases were pregnenolone (300-fold), progesterone (199-fold), 17α-hydroxypregnenolone (187-fold) and deoxycorticosterone (82-fold). Conclusion Using LC-MS/MS we successfully measured 10 corticosteroids in peripheral and adrenal vein serum samples under pre and post ACTH stimulation. This study demonstrates the primary adrenal steroid products and their response to ACTH. PMID:22150161

  18. [Determination of 250 pesticide residues in vegetables using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Aizhi; Wang, Quanlin; Cao, Lili; Li, Yu; Shen, Hao; Shen, Jian; Zhang, Shufen; Man, Zhengyin

    2016-02-01

    A multiresidue analytical method for the determination of 250 pesticide residues in vegetables was developed by using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The target compounds were extracted with acetonitrile containing 1% (v/v) acetic acid, purified by a mixed sorbent of MgSO4, primary secondary amine (PSA), graphitized carbon black (GCB) and C18, separated on a Waters ACQUITY™ UPLC BEH C18 column (100 mm x 2. 1 mm, 1.7 µm) and detected by UPLC-MS/MS. Anhydrous magnesium sulfate was used as a dewatering agent. The effects of the amounts of MgSO4, PSA, GCB and C18 added on the recoveries of 250 pesticides were investigated. The results showed that the purification effect was best when 300 mg MgSO4, 200 mg PSA, 10 mg GCB and 100 mg C18 in 2 mL of the extract were added. For the 250 pesticide residues, the limits of detection (LODs) of the method were from 0. 01 to 50. 00 g/kg. The recoveries obtained ranged from 60. 1% to 120% at three spiked levels in Chinese chives with the relative standard deviations between 3. 5% and 19. 5% using matrix matched external standard method. The results showed that the method is able to meet requirements of the multiresidue detection of the 250 pesticides in vegetable. The method has the advantages of rapidity, simplicity, high sensitivity and better purification effect. It is suitable for the rapid determination of the common pesticides in vegetables, and it provides a strong guarantee for the risk assessments of the quality and safety of vegetables. PMID:27382720

  19. Quantification of L-ergothioneine in human plasma and erythrocytes by liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Ling-Zhi; Thuya, Win-Lwin; Toh, Dorothy Su-Lin; Lie, Michael George-Limenta; Lau, Jie-Ying Amelia; Kong, Li-Ren; Wan, Seow-Ching; Chua, Kian-Ngiap; Lee, Edmund Jon-Deoon; Goh, Boon-Cher

    2013-03-01

    A sensitive analytical method has been developed and validated for the quantification of L-ergothioneine in human plasma and erythrocytes by liquid chromatography-tandem mass spectrometry. A commercially available isotope-labeled L-ergothioneine-d9 is used as the internal standard. A simple protein precipitation with acetonitrile is utilized for bio-sample preparation prior to analysis. Chromatographic separation of L-ergothioneine is conducted using gradient elution on Alltime C18 (150 mm × 2.1 mm, 5 µ). The run time is 6 min at a constant flow rate of 0.45 ml/min. The mass spectrometer is operated under a positive electrospray ionization condition with multiple reaction monitoring mode. The mass transitions of L-ergothioneine and L-ergothioneine-d9 are m/z 230 > 127 and m/z 239 > 127, respectively. Excellent linearity [coefficient of determination (r(2)) ≥ 0.9998] can be achieved for L-ergothioneine quantification at the ranges of 10 to 10,000 ng/ml, with the intra-day and inter-day precisions at 0.9-3.9% and 1.3-5.7%, respectively, and the accuracies for all quality control samples between 94.5 and 101.0%. This validated analytical method is suitable for pharmacokinetic monitoring of L-ergothioneine in human and erythrocytes. Based on the determination of bio-samples from five healthy subjects, the mean concentrations of L-ergothioneine in plasma and erythrocytes are 107.4 ± 20.5 ng/ml and 1285.0 ± 1363.0 ng/ml, respectively. PMID:23494799

  20. Simultaneous quantification of atenolol and chlorthalidone in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Shah, Jaivik V; Patel, Daxesh P; Shah, Priyanka A; Sanyal, Mallika; Shrivastav, Pranav S

    2016-02-01

    A simple, sensitive and reproducible ultra-performance liquid chromatography-tandem mass spectrometry method has been developed for the simultaneous determination of atenolol, a β-adrenergic receptor-blocker and chlorthalidone, a monosulfonamyl diuretic in human plasma, using atenolol-d7 and chlorthalidone-d4 as the internal standards (ISs). Following solid-phase extraction on Phenomenex Strata-X cartridges using 100 μL human plasma sample, the analytes and ISs were separated on an Acquity UPLC BEH C18 (50 mm × 2.1 mm, 1.7 µm) column using a mobile phase consisting of 0.1% formic acid-acetonitrile (25:75, v/v). A tandem mass spectrometer equipped with electrospray ionization was used as a detector in the positive ionization mode for both analytes. The linear concentration range was established as 0.50-500 ng/mL for atenolol and 0.25-150 ng/mL for chlorthalidone. Extraction recoveries were within 95-103% and ion suppression/enhancement, expressed as IS-normalized matrix factors, ranged from 0.95 to 1.06 for both the analytes. Intra-batch and inter-batch precision (CV) and accuracy values were 2.37-5.91 and 96.1-103.2%, respectively. Stability of analytes in plasma was evaluated under different conditions, such as bench-top, freeze-thaw, dry and wet extract and long-term. The developed method was superior to the existing methods for the simultaneous determination of atenolol and chlorthalidone in human plasma with respect to the sensitivity, chromatographic analysis time and plasma volume for processing. Further, it was successfully applied to support a bioequivalence study of 50 mg atenolol + 12.5 mg chlorthalidone in 28 healthy Indian subjects. PMID:26096961

  1. Effect of D-allose on prostate cancer cell lines: phospholipid profiling by nanoflow liquid chromatography-tandem mass spectrometry.

    PubMed

    Jeong, Rae Ung; Lim, Sangsoo; Kim, Myoung Ok; Moon, Myeong Hee

    2011-08-01

    D-Allose, a rare, naturally occurring monosaccharide, is known to exert anti-proliferative effects on cancer cells. The effects of D-allose on the cellular membranes of hormone-refractory prostate cancer cell line (DU145), hormone-sensitive prostate cancer cell line (LNCaP), and normal prostate epithelial cells (PrEC) were studied at the molecular level by phospholipid (PL) profiling using a shotgun lipidomic method. The molecular structures of 85 PL species including 23 phosphatidylcholines, 12 phosphatidylethanolamines (PEs), 11 phosphatidylserines (PSs), 16 phosphatidylinositols, 9 phosphatidic acids (PAs), and 14 phosphatidylglycerols (PGs) were identified by data-dependent collision-induced dissociation of nanoflow liquid chromatography-tandem mass spectrometry, and the PL amounts were quantified. The addition of D-allose to prostate cancer cell lines during their growth phases had negligible or decreased effects on the relative regulation of PL species, but several new PS molecules (two for DU145 and three for LNCaP) emerged. In contrast, experiments on the PrEC cell line revealed that some high abundant species (14:0/14:0-PE, 16:2/16:0-PG, and 20:6/18:1-PA) showed significant increases in concentration. These findings support a mechanism for the anti-proliferative effect of D-allose on prostate cancer cell lines that involves the induction of programmed cell death since PS molecules are known to induce apoptosis. Principal component analysis was carried out to examine differences in PL distributions among the three cell lines promoted by D-allose. PMID:21633842

  2. Simultaneous analysis of buprenorphine, methadone, cocaine, opiates and nicotine metabolites in sweat by liquid chromatography tandem mass spectrometry

    PubMed Central

    Concheiro, Marta; Shakleya, Diaa M.

    2013-01-01

    A liquid chromatography tandem mass spectrometry method for buprenorphine (BUP), norbuprenorphine (NBUP), methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylecgonine, ecgonine methyl ester (EME), morphine, codeine, 6-acetylmorphine, heroin, 6-acetylcodeine, cotinine, and trans-3′-hydroxycotinine quantification in sweat was developed and comprehensively validated. Sweat patches were mixed with 6 mL acetate buffer at pH 4.5, and supernatant extracted with Strata-XC-cartridges. Reverse-phase separation was achieved with a gradient mobile phase of 0.1% formic acid and acetonitrile in 15 min. Quantification was achieved by multiple reaction monitoring of two transitions per compound. The assay was a linear 1–1,000 ng/patch, except EME 5–1,000 ng/patch. Intra-, inter-day and total imprecision were <10.1%CV, analytical recovery 87.2–107.7%, extraction efficiency 35.3– 160.9%, and process efficiency 25.5–91.7%. Ion suppression was detected for EME (−63.3%) and EDDP (−60.4%), and enhancement for NBUP (42.6%). Deuterated internal standards compensated for these effects. No carryover was detected, and all analytes were stable for 24 h at 22 °C, 72 h at 4 °C, and after three freeze/thaw cycles. The method was applied to weekly sweat patches from an opioid-dependent BUP-maintained pregnant woman; 75.0% of sweat patches were positive for BUP, 93.8% for cocaine, 37.5% for opiates, 6.3% for methadone and all for tobacco biomarkers. This method permits a fast and simultaneous quantification of 14 drugs and metabolites in sweat patches, with good selectivity and sensitivity. PMID:21125263

  3. [Simultaneous determination of ten antibiotics in pharmaceutical wastewater using ultra-high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Qiu, Panzi; Guo, Xinyan; Wang, Na; Kong, Xiangji; He, Hua

    2015-07-01

    A simultaneous analytical method was established for ten selected antibiotics from three categories in pharmaceutical wastewater with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The water samples were enriched and cleaned-up by solid phase extraction cartridges. The types of solid phase extraction cartridges and eluents were optimized by comparing the recoveries of the analytes in water samples under different conditions. The target compounds were separated on an Agilent C18 column (75 mmx 2.1 mm, 2.7 μm) with the mobile phases of acetonitrile and 0.2% (v/v) formic acid aqueous solution, and then determined by electrospray ionization mass spectrometry (ESI-MS). The results showed that the calibration curves were linear in the range of 0.1-1000 μg/L (r2>0.995). The limits of detection (LODs, S/N≥3) and the limits of quantification (LOQs, S/N≥10) of the ten compounds were 0.07-4.37 ng/L and 0.22-14.55 ng/L, respectively. The recovery experiments were performed with samples spiked in the range of 0.002-40 μg/L. The recoveries of the target compounds were in the range of 50.4%-114.1% (RSDs≤9.89%, n=3). Based on this analytical method, the raw and treated sewage samples from a pharmaceutical manufacturer wastewater treatment plant in Jiangsu Province were analyzed. Three compounds were detected in the samples from different sewage treatment units in the range of 0.46-1033.60 μg/L. It shows that the method is accurate, reliable, highly sensitive and can be used to analyze the water samples of pharmaceutical wastewater treatment plant containing aminoglycosides, spiramycin and fluoroquinolones antibiotics. PMID:26672201

  4. Multiresidue analysis of pesticides in straw roughage by liquid chromatography - tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multiresidue analytical method using a modification of the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) sample preparation approach combined with liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis was established and validated for the rapid determination of 69 pesti...

  5. Sensitive, Preclinical Detection of Prions in Brain by nanospray liquid chromatography/tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More sensitive detection of prions in brain is important because it would allow early detection of disease in young animals and assure a safer food supply. We quantitated the amount of proteinase K-resistant prion protein (PrP 27-30) by use of nano-scale liquid chromatography coupled to a tandem ma...

  6. A review of clinical diagnostic applications of liquid chromatography-tandem mass spectrometry.

    PubMed

    Shushan, Bori

    2010-01-01

    Liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) technology is emerging as a complementary method to traditional methodology used for clinical applications. Enhanced specificity and high-throughput capabilities are providing significant benefits to clinical diagnostic laboratories conducting routine analyses. This technology is expected to expand rapidly as scientists focus on more complicated challenges that can be solved efficiently by adding LC/MS/MS to their arsenal of techniques. PMID:20949635

  7. Determination of lincomycin and tylosin residues in honey by liquid chromatography/tandem mass spectrometry.

    PubMed

    Thompson, Thomas S; Noot, Donald K; Calvert, Jane; Pernal, Stephen F

    2005-01-01

    A simple and rapid analytical method was developed for the determination of lincomycin and tylosin residues in honey as part of field studies examining the efficacy and target animal safety of these antibiotics to control American foulbrood disease in honey bees. Residues of the antibiotics were determined using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Honey samples were diluted and injected directly into the LC/MS/MS system without additional cleanup by solid-phase extraction or liquid-liquid partitioning. A six-port valve system was utilized to selectively route eluant from the LC column into the mass spectrometer only during a relatively short portion of the chromatographic run corresponding to the elution of the analytes of interest. Minimal contamination of the MS source chamber was observed despite the analysis of large numbers of samples. Using internal standard quantitation, excellent accuracy and precision were obtained with no apparent matrix-to-matrix variation. Based on the analysis of fortified replicates, the mean percent deviation from the theoretical concentration and the percent relative standard deviation were both less than 10% for tylosin over an analytical range of 10-1000 microg/kg. Slightly higher mean percent deviations and relative standard deviations were observed for the analysis of lincomycin in fortified replicate samples. The method detection limits were determined to be 5 and 2 microg/kg for lincomycin and tylosin, respectively. PMID:15645470

  8. Identification and Quantification of Dimethylamylamine in Geranium by Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Li, J.S.; Chen, M.; Li, Z.C.

    2012-01-01

    A sensitive and reliable method of liquid chromatography–electrospray ionization/tandem mass spectrometry (LC-ESI/MS/ MS) was developed and validated for determining 1,3-dimethylamylamine (1,3-DMAA) and 1,4-dimethylamylamine (1,4-DMAA) in geranium plants (Pelargonium graveolens). The sample was extracted with 0.5 M HCl and purified by liquid-liquid partition with hexane. The parameters for reverse-phase (C18) LC and positive ESI/MS/MS were optimized. The matrix effect, specificity, linearity, precision, accuracy and reproducibility of the method were determined and evaluated. The method was linear over a range of 0.10–10.00 ng/mL examined, with R2 of 0.99 for both 1,3-DMAA and 1,4-DMAA. The recoveries from spiked concentrations between 5.00–40.00 ng/g were 85.1%–104.9% for 1,3-DMAA, with relative standard deviation (RSD) of 2.9%–11.0%, and 82.9%–101.8% for 1,4-DMAA, with RSD of 3.2%–11.7%. The instrument detection limit was 1–2 pg for both DMAAs. The quantification limit was estimated to be 1–2 ng/g for the plant sample. This method was successfully applied to the quantitative determination of 1,3- and 1,4-DMAA in both geranium plant and geranium oil. PMID:22915838

  9. Profiling pneumococcal type 3-derived oligosaccharides by high resolution liquid chromatography-tandem mass spectrometry

    PubMed Central

    Li, Guoyun; Li, Lingyun; Xue, Changhu; Middleton, Dustin; Linhardt, Robert J.; Avci, Fikri Y.

    2015-01-01

    Pneumococcal type-3 polysaccharide (Pn3P) is considered a major target for the development of a human vaccine to protect against Streptococcus pneumonia infection. Thus, it is critical to develop methods for the preparation and analysis of Pn3P-derived oligosaccharides to better understand its immunological properties. In this paper, we profile oligosaccharides, generated by the free radical depolymerization of Pn3P, using liquid chromatography (LC)-tandem mass spectrometry (MS/MS). Hydrophilic liquid interaction chromatography (HILIC)-mass spectrometry (MS) revealed a series of oligosaccharides with an even- and odd-number of saccharide residues, ranging from monosaccharide, degree of polymerization (dp1) to large oligosaccharides up to dp 20, generated by free radical depolymerization. Isomers of oligosaccharides with an even number of sugar residues were easily separated on a HILIC column, and their sequences could be distinguished by comparing MS/MS of these oligosaccharides and their reduced alditols. Fluorescent labeling with 2-aminoacridone (AMAC) followed by reversed phase (RP)-LC-MS/MS was applied to analyze and sequence poorly separated product mixtures, as RP-LC affords higher resolution of AMAC-labeled oligosaccharides than does HILIC-based separation. The present methodology can be potentially applied to profiling other capsular polysaccharides. PMID:25913329

  10. Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology - An update.

    PubMed

    Remane, Daniela; Wissenbach, Dirk K; Peters, Frank T

    2016-09-01

    Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) is a well-established and widely used technique in clinical and forensic toxicology as well as doping control especially for quantitative analysis. In recent years, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in biological matrices have been developed. Such methods have proven particularly useful for analysis of so-called new psychoactive substances that have appeared on recreational drug markets throughout the world. Moreover, the evolvement of high resolution MS techniques and the development of data-independent detection modes have opened new possibilities for applications of LC-(MS/MS) in systematic toxicological screening analysis in the so called general unknown setting. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2010. PMID:27452180

  11. Analysis of drugs of abuse in wastewater by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    van Nuijs, Alexander L N; Tarcomnicu, Isabela; Bervoets, Lieven; Blust, Ronny; Jorens, Philippe G; Neels, Hugo; Covaci, Adrian

    2009-10-01

    The simultaneous analysis of nine drugs of abuse (DOAs) and their metabolites (amphetamine, methamphetamine, methylenedioxymethamphetamine, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, cocaine, benzoylecgonine, ecgonine methyl ester and 6-monoacetylmorphine) in wastewater based on hydrophilic interaction liquid chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS) was optimised and validated. For each analyte, the deuterated analogue was used for quantification. The separation by HILIC showed good performance for all compounds, especially for the hydrophilic compounds, which elute early (amphetamine-like stimulants) or show no retention (ecgonine methyl ester) in reversed-phase liquid chromatography. Sample preparation based on solid-phase extraction was optimised by comparing Oasis HLB and Oasis MCX sorbents for various parameters such as sample pH, amount of sorbent bed and washing solvent. The method was validated for each compound by assessing the following parameters (following International Conference on Harmonisation guidelines): specificity, limit of quantification (LOQ), linearity, accuracy, precision, recovery and matrix effects. LOQs were 2 ng/L for 6-monoacetylmorphine, ecgonine methyl ester and amphetamine and 1 ng/L for the rest of the compounds, corresponding with the lowest point in the calibration curve. Except for 6-monoacetylmorphine, all compounds were detected from 1 to 819 ng/L in influent wastewater samples (n = 12) collected from 11 different wastewater treatment plants across Belgium. The presence of ecgonine methyl ester in wastewater could be demonstrated for the first time. In the future, the new HILIC-MS/MS method will be applied to assess the use of DOAs in Belgium using the "sewage epidemiology" approach. PMID:19685341

  12. Rapid determination of nitroimidazole residues in honey by liquid chromatography/tandem mass spectrometry.

    PubMed

    Kanda, Maki; Sasamoto, Takeo; Takeba, Kazue; Hayashi, Hiroshi; Kusano, Tomoko; Matsushima, Yoko; Nakajima, Takayuki; Kanai, Setsuko; Takano, Ichiro

    2012-01-01

    We developed a rapid and efficient means of determining residues of four nitroimidazoles-i.e., dimetridazole, ipronidazole, metronidazole, and ronidazole-and three hydrophilic metabolites- i.e., 2-hydroxymethyl-1-methyl-5-nitroimidazole, 1 -methyl-2-(2'-hydroxyisopropyl)-5-nitroimidazole, and 1-(2-hydroxyethyl)-2-hydroxymethyl-nitroimidazole--in honey. We applied a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure improved to suit a nitroimidazole analysis, which is fast (approximately 30 min) and uses less organic solvent. The procedure involves initial single-phase extraction of 5 g of honey with acetonitrile containing 1% acetic acid, followed by liquid-liquid partitioning involving the addition of 5 g sodium chloride, 1.5 g trisodium citrate dihydrate, and 4 g magnesium sulfate. Moreover, matrix from honey was reduced by an SPE method with an alumina-N cartridge. The samples were analyzed using LC/MS/MS. Chromatographic separation of these nitroimidazoles and metabolites was performed in the gradient mode on a pentafluorophenylpropyl-bonded silica column (150x2.0 mm, 3 pm particle size) at 40 degrees C. The mobile phase consisted of a 0.01% acetic acid solution and acetonitrile, and the flow rate was 0.2 mL/min. The method was validated using honey spiked with these nitroimidazoles from 0.1 to 0.5 microg/kg. The overall recovery of the seven nitroimidazoles ranged from 76.1 to 98.5%; intra- and interassay CV values were <9.5 and <14.2%, respectively. The LOQ ranged from 0.1 to 0.5 microg/kg. LC/MS/MS coupled with the QuEChERS method showed good potential as a method for determining nitroimidazole residues in honey. PMID:22816283

  13. Measurement of total and free docetaxel concentration in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Rigo-Bonnin, Raül; Cobo-Sacristán, Sara; Gonzalo-Diego, Núria; Colom, Helena; Muñoz-Sánchez, Carmen; Urruticoechea, Ander; Falo, Catalina; Alía, Pedro

    2016-01-01

    Docetaxel is a semi-synthetic taxane with cytotoxic anti-neoplastic activity and, currently used as anticancer agent in several types of cancer. Docetaxel is highly bound to plasma proteins, and this significantly determines its clearance and activity. Therefore, measurement of free docetaxel in plasma is pharmacologically important when pharmacokinetics is investigated. We developed and validated chromatographic methods by ultra-performance liquid chromatography-tandem mass spectrometry to measure total and free docetaxel concentration in human plasma. The final validated methods involved liquid-liquid extraction followed by dryness under nitrogen evaporation. To measure free docetaxel concentration, sample preparation was preceded by ultrafiltration. Chromatographic separation was achieved using an Acquity(®) UPLC(®) BEH™ (2.1×100 mm id, 1.7 μm) reverse-phase C18 column at a flow rate of 0.4 mL/min, using isocratic elution mode containing ammonium acetate/formic acid in water/methanol (30:70 v/v) as mobile phase. Docetaxel and its internal standard (paclitaxel) were detected by electrospray ionization mass spectrometry in positive ion multiple reaction monitoring mode using mass-to-charge (m/z) transitions of 808.3→527.0 (quantifier) and 808.3→509.0 (qualifier); and 854.3→569.0 (quantifier) and 854,3→509,0 (qualifier), respectively. The run time per sample was 3.5 min. The limits of quantification were 1,95 and 0.42 μg/L and linearity was observed between 1.95 and 1000 and 0.42-100 μg/L for total and free docetaxel, respectively. Coefficients of variation and absolute relative biases were less than 13.8% and 10.0%. Recovery values were greater than 79.4%. Evaluation of the matrix effect showed ion suppression and no carry-over was observed. The validated methods could be useful for both therapeutic drug monitoring and pharmacokinetic studies. They could be applied to daily clinical laboratory practice to measure the concentration of total and free

  14. Rapid analysis of pharmaceuticals and personal care products in fish plasma micro-aliquots using liquid chromatography tandem mass spectrometry.

    PubMed

    Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

    2015-02-27

    A sensitive analytical method based on liquid-liquid extraction (LLE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for rapid analysis of 11 pharmaceuticals and personal care products (PPCPs) in fish plasma micro-aliquots (∼20μL). Target PPCPs included, bisphenol A, carbamazepine, diclofenac, fluoxetine, gemfibrozil, ibuprofen, naproxen, risperidone, sertraline, simvastatin and triclosan. A relatively quicker and cheaper LLE procedure exhibited comparable analyte recoveries with solid-phase extraction. Rapid separation and analysis of target compounds in fish plasma extracts was achieved by employing a high efficiency C-18 HPLC column (Agilent Poroshell 120 SB-C18, 2.1mm×50mm, 2.7μm) and fast polarity switching, enabling effective monitoring of positive and negative ions in a single 9min run. With the exception of bisphenol A, which exhibited relatively high background contamination, method detection limits of individual PPCPs ranged between 0.15 and 0.69pg/μL, while method quantification limits were between 0.05 and 2.3pg/μL. Mean matrix effect (ME) values ranged between 65 and 156% for the various target analytes. Isotope dilution quantification using isotopically labelled internal surrogates was utilized to correct for signal suppression or enhancement and analyte losses during sample preparation. The method was evaluated by analysis of 20μL plasma micro-aliquots collected from zebrafish (Danio rerio) from a laboratory bioaccumulation study, which included control group fish (no exposure), as well as fish exposed to environmentally relevant concentrations of PPCPs. Using the developed LC-MS/MS based method, concentrations of the studied PPCPs were consistently detected in the low pg/μL (ppb) range. The method may be useful for investigations requiring fast, reliable concentration measurements of PPCPs in fish plasma. In particular, the method may be applicable for in situ contaminant biomonitoring, as well as

  15. A simultaneous quantitative method for vitamins A, D and E in human serum using liquid chromatography-tandem mass spectrometry.

    PubMed

    Albahrani, Ali A; Rotarou, Victor; Roche, Peter J; Greaves, Ronda F

    2016-05-01

    Non-classical roles of fat-soluble vitamins (FSVs) in many pathologies including cancer have been identified. There is also evidence of hormonal interactions between two of these vitamins, A and D. As a result of this enhanced clinical association with disease, translational clinical research and laboratory requests for FSV measurement has significantly increased. However there are still gaps in the analytical methods available for the measurement of these vitamins. This study aimed to develop a method for simultaneous quantification of 25-hydroxyvitamin-D2 (25-OHD2), 25-hydroxyvitamin-D3 (25-OHD3) and its 3-epimer (epi-25-OHD3), retinol and α-tocopherol in human serum using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The procedure was developed and validated across two LC-MS/MS platforms, using commercial calibrators referenced to certified reference materials, controls, and deuterated internal standards. The samples were prepared by liquid-liquid extraction prior to injection and LC separation (using a Pursuit-PFP column) on two Agilent MS/MS systems (6410 and 6490) in electrospray ionisation positive mode with multiple reaction monitoring. Identification and quantification of 25-OHD3 from its 3-epimer as well as 25-OHD2, retinol and α-tocopherol were achieved. The dynamic ranges were 4-160 nmol/L for 25-OHD2 and epi-25-OHD3, 4-200 nmol/L for 25-OHD3, 0.1-4.0μmol/L for retinol and 4-70μmol/L for α-tocopherol with correlation (r(2)) of 0.997-0.998. Based on participation in an external quality assurance program, the overall performance of the simultaneous methods were: imprecision (CV%) and inaccuracy (average bias) 3.0% and 3.2 nmol/L, respectively, for 25-OHD3; 5.0% and 0.04μmol/L, respectively, for retinol; and 4.7% and 0.2μmol/L, respectively, for α-tocopherol. In summary, two simple LC-MS/MS methods were successfully developed and validated for the simultaneous quantification of the three vitamin D metabolites (25-OHD2, 25-OHD3 and 3

  16. Determination of Albendazole and Metabolites in Silkworm Bombyx mori Hemolymph by Ultrafast Liquid Chromatography Tandem Triple Quadrupole Mass Spectrometry

    PubMed Central

    Li, Li; Xing, Dong-Xu; Li, Qing-Rong; Xiao, Yang; Ye, Ming-Qiang; Yang, Qiong

    2014-01-01

    Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO2) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO2-NH2). Calibration curves had good linearities with R2 of 0.9905–0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO2 and 5.94 ng/mL for ABZSO2-NH2. Recoveries were 93.12%–103.83% for ABZ, 66.51%–108.51% for ABZSO, 96.85%–105.6% for ABZSO2 and 96.46%–106.14% for ABZSO2-NH2, (RSDs <8%). Accuracy, precision and stability tests showed acceptable variation in quality control (QC) samples. This analytical method successfully determined albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO2 increased and then fell, while ABZSO2-NH2 level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO2 rising over time. PMID:25255321

  17. Determination of gestagens in kidney fat by liquid chromatography tandem mass spectrometry.

    PubMed

    Lõhmus, Madis; Kender, Tiia

    2007-03-14

    The use of gestagens in animal fattening is prohibited within the European Union. Recently, the use of spectrometric methods for the detection and confirmation of banned substances was made obligatory. Therefore, conventional high-performance liquid chromatographic (HPLC) methods have been superseded. It has been possible to couple a previously described HPLC method for the determination of acetyl-gestagens in kidney fat to tandem mass spectrometry (LC-MS/MS). The decision limits CCalpha and the detection capability CCbeta are found to be below the minimum required performance limit (MRPL) established for medroxyprogesterone acetate (MPA) at 1 microg kg(-1). The calculated values for CCalpha are as follows: megestrol acetate (MGA)--0.15 microg kg(-1), melengesterol acetate (MLA)--0.15 microg kg(-1), chlormadinone acetate (CMA)--0.37 microg kg(-1) and for medroxyprogesterone acetate (MPA)--0.24 microg kg(-1). The CCbeta values for these compounds have been determined as 0.19, 0.19, 0.47 and 0.32 microg kg(-1), respectively. PMID:17386717

  18. Determination of dapoxetine in rat plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Kim, Tae Kon; Kim, In Sook; Hong, Seok Hyun; Choi, Yun Kyoung; Kim, Hohyun; Yoo, Hye Hyun

    2013-05-01

    In this study, we describe and validate a rapid and sensitive method for quantitation of dapoxetine in rat plasma by using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI/MS/MS). Plasma samples were prepared by protein precipitation with acetonitrile, and sildenafil was used as an internal standard (IS). The mobile phase consisted of 0.5% formic acid/acetonitrile (60:40, v/v); a C18 reversed-phase column (2.0 × 50 mm, 1.7 μm) was used for chromatographic separation. Multiple reaction monitoring (MRM) was used in the positive ion mode for mass spectrometric detection. The calibration curve for dapoxetine was linear (r(2)=0.999) in the concentration range of 1-500 ng/mL. The intra- and inter-day precision was between 3.8% and 8.3%, and the intra- and inter-day accuracy was between 101.1% and 109.0%. Dapoxetine was found to be stable in various conditions with the recoveries>87.0% (RSD <7.2%). The method was found to be specific, precise, and accurate, and no matrix effect was observed. Our results suggest that this method can be successfully applied in pharmacokinetic studies of dapoxetine in rat plasma. PMID:23542722

  19. Analysis of antithyroid drugs in surface water by using liquid chromatography-tandem mass spectrometry.

    PubMed

    Pérez-Fernández, Virginia; Marchese, Stefano; Gentili, Alessandra; García, María Ángeles; Curini, Roberta; Caretti, Fulvia; Perret, Daniela

    2014-11-01

    This paper describes development and validation of a new method for the simultaneous determination of six antithyroid drugs (ATDs) in surface waters by using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Target compounds include two ATD classes: thiouracil derivatives (thiouracil (TU), methyl-thiouracil (MTU), propyl-thiouracil (PTU), phenyl-thiouracil (PhTU)) and imidazole derivatives (tapazole (TAP), and mercaptobenzimidazole (MBI)). Sensitivity and selectivity of the LC-multiple reaction monitoring (MRM) analysis allowed applying a simple pre-concentration procedure and "shooting" the concentrated sample into the LC-MS/MS system without any other treatment. Recoveries were higher than 75% for all analytes. Intra-day precision and inter-day precision, calculated as relative standard deviation (RSD), were below 19 and 22%, respectively. Limits of detection (LODs) ranged from 0.05 to 0.25 μg/L; limits of quantitation (LOQs) varied between 0.15 and 0.75 μg/L. The validated method was successfully applied to the analysis of ATD residues in surface water samples collected from the Tiber River basin and three lakes of Lazio (central Italy). The analytes were quantified based on matrix-matched calibration curves with mercaptobenzimidazole-d4 (MBI-d4) as the internal standard (IS). The most widespread compound was TAP, one of the most common ATDs used in human medicine, but also TU and MBI were often detected in the analysed samples. PMID:25287266

  20. Global Analysis of the Membrane Subproteome of Pseudomonas aeruginosa using Liquid Chromatography-Tandem Mass Spectrometry

    SciTech Connect

    Blonder, Josip; Goshe, Michael B.; Xiao, Wenzhong; Camp, David G.; Wingerd, Mark A.; Davis, Ronald W.; Smith, Richard D.

    2004-05-30

    Pseudomonas aeruginosa is one of the most significant opportunistic bacterial pathogens in humans causing infections and premature death in patients with cystic fibrosis, AIDS, severe burns, organ transplants or cancer. Liquid chromatography coupled online with tandem mass spectrometry (LC-MS/MS) was used for the large-scale proteomic analysis of the P. aeruginosa membrane subproteome. Concomitantly, an affinity labeling technique, using iodoacetyl-PEO biotin to tag cysteinyl-containing proteins, permitted the enrichment and detection of lower abundance membrane proteins. The application of these approaches resulted in the identification of 786 proteins. A total of 333 proteins (42%) had a minimum of one transmembrane domain (TMD; ranging from 1 to 14) and 195 proteins were classified as hydrophobic based on their positive GRAVY values (ranging from 0.01 to 1.32). Key integral inner and outer membrane proteins involved in adaptation and antibiotic resistance were conclusively identified, including the detection of 53% of all predicted opr-type porins (outer integral membrane proteins) and all the components of the mexA-mexB-oprM transmembrane protein complex. This work represents the most comprehensive qualitative proteomic analysis of the membrane subproteome of P. aeruginosa and for prokaryotes in general to date.

  1. Quantitative analysis of mitragynine in human urine by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Lu, Shijun; Tran, Buu N; Nelsen, Jamie L; Aldous, Kenneth M

    2009-08-15

    Mitragynine is the primary active alkaloid extracted from the leaves of Mitragyna speciosa Korth, a plant that originates in South-East Asia and is commonly known as kratom in Thailand. Kratom has been used for many centuries for their medicinal and psychoactive qualities, which are comparable to that of opiate-based drugs. Kratom abuse can lead to a detectable content of mitragynine residue in urine. Ultra trace amount of mitragynine in human urine was determined by a high performance liquid chromatography coupled to an electrospray tandem mass spectrometry (HPLC-ESI/MS/MS). Mitragynine was extracted by methyl t-butyl ether (MTBE) and separated on a HILIC column. The ESI/MS/MS was accomplished using a triple quadrupole mass spectrometer in positive ion detection and multiple reactions monitoring (MRM) mode. Ajmalicine, a mitragynine's structure analog was selected as internal standard (IS) for method development. Quality control (QC) performed at three levels 0.1, 1 and 5 ng/ml of mitragynine in urine gave mean recoveries of 90, 109, and 98% with average relative standard deviation of 22, 12 and 16%, respectively. The regression linearity of mitragynine calibration ranged from 0.01 to 5.0 ng/ml was achieved with correlation coefficient greater than 0.995. A detection limit of 0.02 ng/ml and high precision data within-day and between days analysis were obtained. PMID:19577523

  2. [Determination of 25 quinolones in cosmetics by liquid chromatography-tandem mass spectrometry].

    PubMed

    Lin, Li; Zhang, Yi; Tu, Xiaoke; Xie, Liqi; Yue, Zhenfeng; Kang, Haining; Wu, Weidong; Luo, Yao

    2015-03-01

    An analytical method was developed for the simultaneous determination of 25 quinolones, including danofloxacin mesylate, enrofloxacin, flumequine, oxloinic acid, ciprofloxacin, sarafloxacin, nalidixic acid, norfloxacin, and ofloxacin etc in cosmetics using direct extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Cosmetic sample was extracted by acidified acetonitrile, defatted by n-hexane and separated on Poroshell EC-C18 column with gradient elution program using acetonitrile and water (both containing 0. 1% formic acid) as the mobile phases and analyzed by LC-ESI-MS/MS under the positive mode using multiple reaction monitoring (MRM). The interference of matrix was reduced by the matrix-matched calibration standard curve. The method showed good linearities over the range of 1-200 mg/kg for the 25 quinolones with good linear correlation coefficients (r ≥ 0.999). The method detection limit of the 25 quinolones was 1.0 mg/kg, and the recoveries of all analytes in lotion, milky and cream cosmetics matrices ranged from 87.4% to 105% at the spiked levels of 1, 5 and 10 mg/kg with the relative standard deviations (RSD) of 4.54%-19.7% (n = 6). The results indicated that this method is simple, fast and credible, and suitable for the simultaneous determination of the quinolones in the above three types of cosmetics. PMID:26182469

  3. Simultaneous determination of multiple androgens in mice organs with liquid chromatography tandem mass spectrometry.

    PubMed

    Soh, Shu Fang; Yin, Xiaoxing; Sun, Jiaquan; Li, Jun; Yong, Eu Leong; Wei, Qunli; Gong, Yinhan

    2015-11-10

    Prostate cancer (PCa) is the most commonly diagnosed cancer in men worldwide. It is essentially dependent on potent androgens, such as testosterone (T) and dihydrotestosterone (DHT). The precursors of T and DHT, which includes androstenedione (A4) and dihydroepiandrosterone (DHEA), and also the metabolites of DHT, 5α-androstane-3α,17β-diol (3α-Diol) and 5α-androstane-3β,17β-diol (3β-Diol) are able to affect the development of PCa. Therefore, it is important to simultaneously determine all these key androgens. This study aims to develop and validate an LC-MS/MS quantification method to simultaneously detect and quantify the six related androgens, including T, DHT, A4, DHEA, 3α-Diol, and 3β-Diol in limited sample volume. The sample preparation involved liquid extraction with methyl tert-butyl ether (MTBE), following by chemical derivatisation with hydroxylamine. The limits of quantitation for T, DHT, A4, and DHEA were 0.05nM and 3α-Diol and 3β-Diol were 0.5nM with S/N ratio of at least 5:1 by using 100μL samples. PMID:26291790

  4. Determination of phenylephrine in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Feng, Sheng; Zhao, Qian; Jiang, Ji; Hu, Pei

    2013-02-01

    This paper described a sensitive and rapid method based on ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) for the determination of phenylephrine in human plasma. Plasma samples were pre-purified by solid-phase extraction (SPE). The chromatographic separation was achieved with BEH HILIC column using a mixture of 10mM pH 3.5 ammonium formate and acetonitrile (10:90, v/v) under isocratic conditions at a flow rate of 0.4 mL/min. The mass spectrometry was carried out using positive electrospray ionization (ESI) and data acquisition was carried out in the multiple reaction monitoring (MRM) mode. The method was fully validated over the concentration range of 10.0-5000 pg/mL. The lower limit of quantification (LLOQ) was 10.0 pg/mL. Inter- and intra-batch precision was less than 15% and the accuracy was within 85-115%. Extraction recovery was 78.5%. Selectivity, matrix effects and stability were also validated. The method was applied to the pharmacokinetic study of phenylephrine hydrochloride in Chinese subjects. PMID:23314401

  5. Ultra performance liquid chromatography tandem mass spectrometry performance evaluation for analysis of antibiotics in natural waters.

    PubMed

    Tamtam, Fatima; Mercier, Fabien; Eurin, Joëlle; Chevreuil, Marc; Le Bot, Barbara

    2009-03-01

    An ultra performance liquid chromatography electrospray tandem mass spectrometry (UPLC/MS/MS) method was developed and validated for the determination of 17 antibiotics in natural waters in one single extraction and chromatographic procedure. Gradient separation conditions were optimised for 17 compounds belonging to five different antibiotic groups: quinolones (oxolinic acid, nalidixic acid, pipemidic acid, flumequine), fluoroquinolones (enoxacin, ciprofloxacin, norfloxacin, ofloxacin, enrofloxacin, sarafloxacin, danofloxacin, difloxacin, lomefloxacin), sulphonamides (sulphamethoxazole, sulphamethazine), nitro-imidazole (ornidazole) and diaminopyrimidine (trimethoprim). The separation of all compounds, obtained using a 1.7 microm particle size column (100 mm x 2.1 mm), was achieved within 10 min time. Water samples were adjusted to pH 7 and extracted using Oasis hydrophilic-lipophilic balance (HLB) solid phase extraction cartridges. After elution with methanol and concentration, extracts were injected in a C18 column (Acquity UPLC BEH C18) and detected by tandem mass spectrometry. Average recovery from 100 ng L(-1) fortified samples was higher than 70% for most of the compounds, with relative standard deviations below 20%. Performances of the method (recoveries, detection limit, quantification limit and relative standard deviation) and matrix effects were studied, and results obtained showed that method was suitable for routine analysis of antibiotics in surface water. Samples analysis from Seine River (France) confirmed the interest of antibiotic contamination evaluation in that area. PMID:19148627

  6. Analysis of Nucleosides in Municipal Wastewater by Large-Volume Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Brewer, Alex J.; Lunte, Craig

    2015-01-01

    Nucleosides are components of both DNA and RNA, and contain either a ribose (RNA) or 2deoxyribose (DNA) sugar and a purine or pyrimidine base. In addition to DNA and RNA turnover, modified nucleosides found in urine have been correlated to a diminished health status associated with AIDS, cancers, oxidative stress and age. Nucleosides found in municipal wastewater influent are potentially useful markers of community health status, and as of now, remain uninvestigated. A method was developed to quantify nucleosides in municipal wastewater using large-volume injection, liquid chromatography, and mass spectrometry. Method accuracy ranged from 92 to 139% when quantified by using isotopically labeled internal standards. Precision ranged from 6.1 to 19% of the relative standard deviation. The method’s utility was demonstrated by the analysis of twenty-four hour composite wastewater influent samples that were collected over a week to investigate community nucleoside excretion. Nucleosides originating from RNA were more abundant that DNA over the study period, with total loads of nucleosides ranging from 2 to 25 kg/day. Given this relatively high amount of nucleosides found over the study period they present an attractive analyte for the investigation of community health. PMID:26322136

  7. Determination of faropenem in human plasma and urine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Gao, Shouhong; Chen, Wansheng; Tao, Xia; Miao, Haijun; Yang, Shaolin; Wu, Rong

    2008-01-01

    A simple, rapid and sensitive liquid chromatography/electrospray tandem mass spectrometry (LC-MS/MS) quantitative detection method, using cefalexin as internal standard, was developed for the analysis of faropenem in human plasma and urine. After precipitation of the plasma proteins with acetonitrile, the analytes were separated on a C18 reversed-phase column with 0.1% formic acid-methanol (45:55, v/v) and detected by electrospray ionization mass spectrometry in positive multiple reaction monitoring mode. Calibration curves with good linearities (r=0.9991 for plasma sample and r=0.9993 for urine sample) were obtained in the range 5-4000 ng/mL for faropenem. The limit of detection was 5 ng/mL. Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of faropenem in humans, and to our knowledge, it is the first time the pharmacokinetic of faropenem has been elucidated in vivo using LC-MS/MS. PMID:17604362

  8. Ultraperformance liquid chromatography tandem mass spectrometry determination of cyanogenic glucosides in Trifolium species.

    PubMed

    Muzashvili, Tamar; Moniuszko-Szajwaj, Barbara; Pecio, Lukasz; Oleszek, Wieslaw; Stochmal, Anna

    2014-02-26

    Cyanogenic glucosides were analyzed by ultra-high-performance liquid chromatography combined with mass spectrometry in 88 Trifolium species grown at the same site. On the basis of the occurrence of cyanogenic glucosides and the linamarin/lotaustralin ratio species could be grouped into five clusters. Cluster C1 included 37 species, which did not contain cyanogens. Cluster C2 (22 species) included plants containing only lotaustralin. In clusters C3 (14 species), C4 (13 species), and C5 (2 species) both linamarin and lotaustralin were present but at different ratios. In C3 and C4 the linamarin/lotaustralin ratio was below 1, whereas in cluster C5 the ratio was much higher. Generally, the total content of cyanogens was below 500 μg/g dry matter. Only in Trifolium repens var. biasoletti and Trifolium montanum extremely high cyanogen concentrations were observed. There was no general rule of occurrence of cyanogens. Samples of the same species from different countries accumulated cyanogens or could be free of these compounds. PMID:24476020

  9. Selective extraction and determination of neonicotinoid insecticides in wine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Rodríguez-Cabo, T; Casado, J; Rodríguez, I; Ramil, M; Cela, R

    2016-08-19

    A simplified, high throughput procedure for the determination of five neonicotinoid insecticides in red and white wines, using liquid chromatography (LC)-tandem mass spectrometry (MS/MS), is presented. The effects of different experimental parameters (extraction sorbent, solvent elution and clean-up conditions) in the efficiency and the selectivity of the sample preparation process were assessed through calculation of the extraction yields and the matrix effects (MEs). Wines (10mL) were concentrated using OASIS HLB cartridges, on-line connected to Florisil clean-up cartridges, with acetonitrile serving as the elution solvent. The extract (5mLvol) was concentrated to 1mL and injected in the LC-ESI-MS/MS system. The optimized procedure provided quantitative extraction yields at the same time that the efficiency of ESI ionization remained unchanged between standards and sample extracts. Overall recoveries, calculated against authentic standards in ACN, varied between 77 and 119% and the attained limits of quantification remained below 0.2ngmL(-1). Analysis of commercial wines revealed imidacloprid residues in more than 50% of processed samples, with a maximum level of 14ngmL(-1). PMID:27425763

  10. [Determination of five synthetic sweeteners in wines using high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Ji, Chao; Feng, Feng; Chen, Zhengxing; Sun, Li; Chu, Xiaogang

    2010-08-01

    A high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS) method for the determination of five synthetic sweeteners (acesulfame, sodium saccharin, sodium cyclamate, aspartame and neotame) in wines has been developed. The HPLC separation was carried out on an Ultimate C18 column (100 mm x 2.1 mm, 3 microm). Several parameters, including the composition and pH of the mobile phase, column temperature and the monitor ions, were optimized for improving the chromatographic performance and the sensitivity of determination. The results demonstrated that the separation can be completed in less than 5 min by gradient elution with 20 mmol/L ammonium formate and 0.1% (v/v) formic acid (pH 3.8) and methanol as the mobile phase. The column temperature was kept at 45 degrees C. When the analytes were detected by ESI -MS/MS under multiple reaction monitoring mode, the detection limits were 0.6, 5, 1, 0.8 and 0.2 microg/L for acesulfame, sodium saccharin, sodium cyclamate, aspartame and neotame, respectively. The average recoveries ranged from 87.2% to 103%. The relative standard deviations were not more than 1.2%. This method is rapid, accurate, highly sensitive and suitable for the quality control of low concentration of the synthetic sweeteners, which are illegally added to wines and other foods with complex matrices. PMID:21261041

  11. Simultaneous determination of acidic pesticides in vegetables and fruits by liquid chromatography--tandem mass spectrometry.

    PubMed

    Shida, Shizuka S; Nemoto, Satoru; Matsuda, Rieko

    2015-01-01

    A sensitive and efficient method has been developed for the simultaneous determination of 73 multi-class acidic pesticides, such as phenoxy acid and sulfonylurea herbicides, in vegetables and fruits. The sample preparation procedure was carefully optimized for the efficient removal of co-extracted matrix components. The method involves extraction of acidic pesticides with acetonitrile containing hydrochloric acid, removal of water from crude extract by salting out, and sequential cleanup by octadecylsilyl silica gel and silica gel columns. For samples containing high amounts of pigments, such as spinach, additional cleanup using a graphitized carbon column was performed prior to liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Recovery tests were performed for five times for each sample of cabbage, spinach, potato, eggplant, orange, and apple fortified at 0.01 mg kg-1. Out of the 73 tested pesticides, 70 for cabbage, 67 for spinach, 69 for potato, 67 for eggplant, 64 for orange, and 70 for apple were within the range of 70-120%, with relative standard deviations below 25%. Nitenpyram and pyrasulfotole showed low recoveries for all the samples tested, probably due to low recoveries from silica gel column. The developed method effectively removed co-extracted matrix components and was highly selective, with no interfering peaks found in the chromatograms of blank samples. The overall results indicate that the developed method is suitable for the quantitative analysis of acidic pesticide residues in vegetables and fruits. PMID:25602148

  12. A rapid quantitative method of carisoprodol and meprobamate by liquid chromatography-tandem mass spectrometry.

    PubMed

    Essler, Shannon; Bruns, Kerry; Frontz, Michael; McCutcheon, J Rod

    2012-11-01

    The identification and quantitation of carisoprodol (Soma) and its chief metabolite meprobamate, which is also a clinically prescribed drug, remains a challenge for forensic toxicology laboratories. Carisoprodol and meprobamate are notable for their widespread use as muscle relaxants and their frequent identification in the blood of impaired drivers. Routine screening is possible in both an acidic/neutral pH screen and a traditional basic screen. An improvement in directed testing quantitations was desirable over the current options of an underivatized acidic/neutral extraction or a basic screen, neither of which used ideal internal standards. A new method was developed that utilized a simple protein precipitation, deuterated internal standards and a short 2-min isocratic liquid chromatography separation, followed by multiple reaction monitoring with tandem mass spectrometry. The linear quantitative range for carisoprodol was determined to be 1-35mg/L and for meprobamate was 0.5-50mg/L. The method was validated for specificity and selectivity, matrix effects, and accuracy and precision. PMID:23040985

  13. Multiclass analysis of antibiotic residues in honey by ultraperformance liquid chromatography-tandem mass spectrometry.

    PubMed

    Vidal, Jose Luis Martínez; Aguilera-Luiz, María Del Mar; Romero-González, Roberto; Frenich, Antonia Garrido

    2009-03-11

    A method has been developed and validated for the simultaneous analysis of different veterinary drug residues (macrolides, tetracyclines, quinolones, and sulfonamides) in honey. Honey samples were dissolved with Na(2)EDTA, and veterinary residues were extracted from the supernatant by solid-phase extraction (SPE), using OASIS HLB cartridges. The separation and determination was carried out by ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), using an electrospay ionization source (ESI) in positive mode. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring (MRM) of two ion transitions per compound to provide a high degree of sensitivity and specificity. The method was validated, and mean recoveries were evaluated at three concentration levels (10, 50, and 100 microg/kg), ranging from 70 to 120% except for doxycycline, erythromycin, and tylmicosin with recovery higher than 50% at the three levels assayed. Relative standard deviations (RSDs) of the recoveries were less than 20% within the intraday precision and less than 25% within the interday precision. The limits of quantification (LOQs) were always lower than 4 microg/kg. The developed procedure was applied to 16 honey samples, and erythromycin, sarafloxacin, and tylosin were found in a few samples. PMID:19195999

  14. Rapid determination of fumonisins in corn-based products by liquid chromatography/tandem mass spectrometry.

    PubMed

    Li, Wei; Herrman, Timothy J; Dai, Susie Y

    2010-01-01

    A simple, fast, and robust method was developed for the determination of fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) in corn-based human food and animal feed (cornmeal). The method involves a single extraction step followed by centrifugation and filtration before analysis by ultra-performance liquid chromatographylelectrospray ionization (UPLC/ESI)-MS/MS. The LC/MS/MS method developed here represents the fastest and simplest procedure (<30 min) among both conventional HPLC methods and other LC/MS methods using SPE cleanup. The potential for high throughput analysis makes the method particularly beneficial for regulatory agencies and analytical laboratories with a high sample volume. A single-laboratory validation was conducted by testing three different spiking levels (200, 500, and 1000 ng/g for FB1 and FB2; 100, 250, and 500 ng/g for FB3) for accuracy and precision. Recoveries of FB1 ranged from 93 to 98% with RSD values of 3-8%. Recoveries of FB2 ranged from 104 to 108%, with RSD values of 2-6%. Recoveries of FB3 ranged from 94 to 108%, with RSD values of 2-5%. PMID:21140660

  15. Determination of 76 pharmaceutical drugs by liquid chromatography-tandem mass spectrometry in slaughterhouse wastewater.

    PubMed

    Shao, Bing; Chen, Dong; Zhang, Jing; Wu, Yongning; Sun, Chengjun

    2009-11-20

    A multi-residue method for the analysis of 76 pharmaceutical agents of nine classes of drugs (tetracyclines, macrolides, fluoroquinolones, beta-agonists, beta-blockers, diuretics, sedatives, sulfonamides and chloramphenicol) in slaughterhouse wastewater and a receiving river is presented. After simultaneous extraction with an Oasis HLB solid-phase extraction (SPE) cartridge and further purification using an amino SPE cartridge, analytes were detected by liquid chromatography-electrospray ionization-tandem mass spectrometry in positive or negative ion mode. Standard addition was used for quantification to overcome unavoidable matrix effects during ESI-MS analysis. Recoveries for most analytes based on matrix-matched calibration in different test matrices were >60%. The method quantification limits of 76 pharmaceuticals were in the range 0.2-30 ng/L. Nineteen compounds of 76 drugs were found in raw and treated slaughterhouse wastewater from four main slaughterhouses in Beijing. Sulfanamides (sulfanilamide, sulfameter), fluoroquenones (ofloxacin, pefloxacin, norfloxacin, ciprofloxacin, enrofloxacin), tetracyclines (tetracycline, oxytetracycline) and macrolides (kitasamycin, tylosin, erythromycin) were most frequently detected, with the highest levels up to approximately 3 microg/L in slaughterhouse wastewater and approximately 1 microg/L in treated wastewater. Illicit drugs for animal feeding such as clenbuterol and diazepam were commonly detected in slaughterhouse wastewater. These analytes were also observed in a river receiving slaughterhouse wastewater, with a highest level of up to 0.2 microg/L. PMID:19825501

  16. Pharmacokinetics and bioavailability assessment of Miltefosine in rats using high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Valicherla, Guru R; Tripathi, Priyanka; Singh, Sandeep K; Syed, Anees A; Riyazuddin, Mohammed; Husain, Athar; Javia, Deep; Italiya, Kishan S; Mishra, Prabhat R; Gayen, Jiaur R

    2016-09-15

    Miltefosine (MFS) is the first effective oral drug for treatment of visceral, mucosal and cutaneous leishmaniasis. In this study, liquid chromatography coupled mass spectrometry (LC-MS/MS) method of MFS was validated in rat plasma and its practical utilization to pharmacokinetic studies in rats for the first time. A rapid, selective and sensitive LC-MS/MS method for MFS in rat plasma was linear over the calibration range of 1-500ng/mL. MFS and Phenacetin (internal standard) were separated on Phenomenex Luna 3μ HILIC 200A (150×4.6mm) column under isocratic condition using methanol: 0.1% formic acid in triple distilled water, 90:10 (v/v) mobile phase at a flow rate of 0.8mL/min. The total chromatographic run time was 4.0min. The intra- and inter-day assay accuracy was observed between 99.45-102.88% and 99.92-101.58%, respectively. The intra- and inter-day assay precision was observed between 2.68-5.54% and 2.35-5.94%, respectively. The validated assay was practically applied to determine the plasma concentrations after oral and intravenous administration of MFS to rats. After oral administration, MFS showed Cmax (3200.00±95.39ng/mL) was observed at 12.00h (tmax) and t1/2 was 102.36±16.65h. The absolute bioavailability of MFS was 60.33±2.32%. PMID:27475453

  17. Measurement of oxidative stress parameters using liquid chromatography-tandem mass spectroscopy (LC-MS/MS)

    SciTech Connect

    Winnik, Witold M. Kitchin, Kirk T.

    2008-11-15

    There is increasingly intense scientific and clinical interest in oxidative stress and the many parameters used to quantify the degree of oxidative stress. However, there remain many analytical limitations to currently available assays for oxidative stress markers. Recent improvements in software, hardware, and instrumentation design have made liquid chromatography and tandem mass spectroscopy (LC-MS/MS) methods optimal choices for the determination of many oxidative stress markers. In particular, LC-MS/MS often provides the advantages of higher specificity, higher sensitivity, and the capacity to determine multiple analytes (e.g. 4-11 oxidative stress markers per LC run) when compared to other available methods, such as gas chromatography-MS, immunoassays, spectrophotometric or flourometric assays. LC-MS/MS methods are also compatible with cleanup and sample preparation methods including prior solid phase extraction or automated two dimensional LC/LC chromatography followed by MS/MS. LC-MS/MS provides three analytical filtering functions: (1) the LC column provides initial separation as each analyte elutes from the column. (2) The first MS dimension isolates ions of a particular mass-to-charge (m/z) ratio. (3) The selected precursor ion is fragmented into product ions that provide structural information about the precursor ion. Quantitation is achieved based on the abundances of the product ions. The sensitivity limits for LC-MS/MS usually lie within the range of fg-pg of analyte per LC on-column injection. In this article, the present capabilities of LC-MS/MS are briefly presented and some specific examples of the strengths of these LC-MS/MS assays are discussed. The selected examples include methods for isoprostanes, oxidized proteins and amino acids, and DNA biomarkers of oxidative stress.

  18. Rapid detection of economic adulterants in fresh milk by liquid chromatography-tandem mass spectrometry.

    PubMed

    Abernethy, Grant; Higgs, Kerianne

    2013-05-01

    A method to aid in the detection of the economically driven adulteration of fresh milk with a range of small, nitrogen containing compounds, including melamine, ammeline, ammelide, cyanuric acid, allantoin, thiourea, urea, biuret, triuret, semicarbazide, aminotriazine, 3- and 4-aminotriazole, cyanamide, dicyandiamide, guanidine, choline, hydroxyproline, nitrate, and a range of amino acids, has been developed. (15)N2-Urea is used as an internal standard. The adulteration of milk with exogenous urea has previously been difficult to detect because of the variation in the naturally occurring levels of urea in milk. However, by monitoring the contaminants biuret and triuret, which comprise up to 1% of synthetic urea, the adulteration of milk with urea-based fertilizer can be detected. We estimate that to be economically viable, adulteration of the order of 90-4000ppm of the above adulterants would need to be added to fresh milk. For most of the compounds, an arbitrary detection threshold of 2ppm is therefore more than sufficient. For biuret, a lower detection threshold, better than 0.5ppm, is desirable and the sensitivity for biuret and triuret can be improved by the post-column addition of lithium to create lithium adducts under electrospray ionisation. Sample handling involves a two-step solvent precipitation method that is deployed in a 96-well plate format, and the hydrophilic interaction liquid chromatography uses a rapid gradient (1.2min). Three separate injections, to detect the positively charged compounds, the negatively charged compounds and amino acids and finally the lithium adducts, are used. This rapid and qualitative survey method may be deployed as a second tier screening method to quickly reduce sample numbers indicated as irregular by an FTIR based screening system, and to direct analysis to appropriate quantification methods. PMID:23540766

  19. Determination of zolpidem in human plasma by liquid chromatography-tandem mass spectrometry for clinical application.

    PubMed

    Byeon, Ji-Yeong; Lee, Hye-In; Lee, Yun-Jeong; Lee, Jung-Eun; Kim, Se-Hyung; Kim, Young-Hoon; Na, Han-Sung; Jang, Choon-Gon; Lee, Seok-Yong

    2015-04-01

    Zolpidem (ZPD) is widely described for the short-term treatment of insomnia. We have developed and validated a simple and rapid liquid chromatography analytical method using tandem mass spectrometry (LC-MS/MS) for the quantification of ZPD in human plasma. Using dibucaine as an internal standard (IS), the analyte was extracted with methyl t-butyl ether (MTBE). Chromatographic separation of ZPD was performed on a reversed-phase Luna C18 column (50 mm × 2.0 mm i.d., 5 μm particles) with a mobile phase of 10mM ammonium formate buffer (pH 3.0)-methanol (15:85, v/v) at a flow rate of 250 μm/min. The total run-time was 2.5 min and the retention times of ZPD and IS were 0.66 and 0.74 min, respectively. The mass-to-charge transition monitored for quantification of ZPD and IS was 308.2→235.2 and 344.0→271.0, respectively. The lower limit of quantification (LLOQ) using 100 μL of human plasma was 0.05 ng/mL and the calibration curves were linear over a range of 0.05-200 ng/mL (r(2)>0.9964). The mean accuracy and precision for intra- and inter-run validation of ZPD were within acceptable limits. In the present LC-MS/MS method, we showed improved sensitivity for quantification of the ZPD in human plasma using lower volume of plasma compared with previously described analytical methods for ZPD. This validated method was successfully applied to a pharmacokinetic study in humans. PMID:25728370

  20. Monitoring algal toxins in lake water by liquid chromatography tandem mass spectrometry.

    PubMed

    Bogialli, Sara; Bruno, Milena; Curini, Roberta; Di Corcia, Antonio; Fanali, Chiara; Laganà, Aldo

    2006-05-01

    Microcystins (MCs) and cylindrospermopsin (CYL) are potent natural toxins produced by cyanobacteria (blue-green algae) that grow worldwide in eutrophic freshwaters and cause animal and human water-based toxicoses. The main purpose of this work has been assessing the contamination levels of some MCs and CYL in eutrophic Italian lake (Albano) water. To do this, we have developed an original analytical method involving MC extraction with a sorbent (Carbograph 4) cartridge. CYL is a highly polar compound that is scarcely retained by any sorbent material. To analyze this toxin, we directly injected 0.5 mL of filtered lake water into the liquid chromatography (LC) column. Analytes were quantified by LC coupled to tandem mass spectrometry in the multireaction monitoring mode. The recovery of five selected MCs added to an analyte free lake water sample at three different concentrations (50, 150, and 500 ng/L) ranged between 93 and 103% with RSD values no larger than 8%. Limits of quantification (LOQ) of the five MCs were within the 2-9 ng/L range, whereas the LOQ of CYL was 300 ng/L. The occurrence and abundance of cyanotoxins in Lake Albano was monitored over four months (Sept-Dec 2004) by analyzing water samples collected monthly at the center of the lake and at different depths (from 0 to -30 m). During survey and with the MS/MS system operating in the parent ion scan mode, we individuated two demethylated forms of MC-RR and one demethylated variety of MC-LR. Demethylated MC-RRs are known to be even more toxic than MC-RR toward zooplanktic grazers. CYL was the most-abundant toxin during the first three monitoring months. To the best of our knowledge, this is the first work reporting concentration levels of CYL in lake water. PMID:16719091

  1. Determination of XLR-11 and its metabolites in hair by liquid chromatography-tandem mass spectrometry.

    PubMed

    Park, Meejung; Yeon, Seonghoon; Lee, Jaesin; In, Sangwhan

    2015-10-10

    Analysis of drugs in hair is often used as a routine method to obtain detailed information about drug ingestion. However, few studies have been conducted on disposition of synthetic cannabinoids including cyclopropylindoles (UR-144 and XLR-11) and their metabolites in hair. XLR-11 has been widely abused in South Korea recently. Identification of metabolites in hair can be an important proof of synthetic cannabinoids use because it can exclude the possibility of passive smoke exposure. In this study, we described a quantitative analytical method of XLR-11 and its metabolites (UR-144, UR-144 N-5-hydroxypentyl metabolite, UR-144 N-4-hydroxypentyl metabolite, UR-144 N-pentanoic acid metabolite and XLR-11 N-4-hydroxypentyl metabolite) in hair by liquid chromatography with ESI-MS/MS. The target analytes were extracted with methanol from washed and cut hair samples and the extracts were evaporated, filtered and analyzed by LC-MS/MS with electrospray ion source in positive-ionization mode. JWH-018-d9 and JWH-018 N-5-hydroxypentyl metabolite-d5 were used as internal standards. Chromatographic separation was completed within 15 min. No interferences were detected in 10 blank hair samples. In intra- and inter-assay precision and accuracy study, CV (%) and bias (%) were below 12. The limit of detection (LOD) was 0.1∼2 pg/mg and the limit of quantification (LOQ) was 0.2-2 pg/mg, respectively. The validation results proved that the method was selective, accurate and precise with acceptable linearity within calibration range. No significant variation was observed by different sources of matrices. This method was applied to hair samples from 14 individual suspects of XLR-11 use. In this result, XLR-11, UR-144, UR-144 N-5-hydroxypentyl metabolite and UR-144 N-pentanoic acid metabolite, XLR-11 N-4-hydroxypentyl metabolite were detected. The concentration of XLR-11 as a parent drug was much higher than other metabolites. UR-144 N-5-hydroxy metabolite and UR-144 N-pentanoic acid

  2. Quantification of cortisol in human eccrine sweat by liquid chromatography - tandem mass spectrometry.

    PubMed

    Jia, Min; Chew, Wade M; Feinstein, Yelena; Skeath, Perry; Sternberg, Esther M

    2016-03-21

    Cortisol has long been recognized as the "stress biomarker" in evaluating stress related disorders. Plasma, urine or saliva are the current source for cortisol analysis. The sampling of these biofluids is either invasive or has reliability problems that could lead to inaccurate results. Sweat has drawn increasing attention as a promising source for non-invasive stress analysis. A sensitive HPLC-MS/MS method was developed for the quantitation of cortisol ((11β)-11,17,21-trihydroxypregn-4-ene-3,20-dione) in human eccrine sweat. At least one unknown isomer that has previously not been reported and could potentially interfere with quantification was separated from cortisol with mixed mode RP HPLC. Detection of cortisol was carried out using atmospheric pressure chemical ionization (APCI) and selected reaction monitoring (SRM) in positive ion mode, using cortisol-9,11,12,12-D4 as internal standard. LOD and LOQ were estimated to be 0.04 ng ml(-1) and 0.1 ng ml(-1), respectively. Linear range of 0.10-25.00 ng ml(-1) was obtained. Intraday precision (2.5%-9.7%) and accuracy (0.5%-2.1%), interday precision (12.3%-18.7%) and accuracy (7.1%-15.1%) were achieved. This method has been successfully applied to the cortisol analysis of human eccrine sweat samples. This is the first demonstration that HPLC-MS/MS can be used for the sensitive and highly specific determination of cortisol in human eccrine sweat in the presence of at least one isomer that has similar hydrophobicity as cortisol. This study demonstrated that human eccrine sweat could be used as a promising source for non-invasive assessment of stress biomarkers such as cortisol and other steroid hormones. PMID:26858998

  3. Determination of 13 Organic Toxicants in Human Blood by Liquid-Liquid Extraction Coupling High-Performance Liquid Chromatography Tandem Mass Spectrometry.

    PubMed

    Song, Aiying

    2016-01-01

    Pesticides and antidepressants are frequently misused in drug-facilitated crime because of their toxicological effect and easy-availability. Therefore, it is essential for the development of a simple and reliable method for the determination of these organic toxicants in biological fluids. Here, we report on an applicable method by the combination of optimized liquid-liquid extraction (LLE) procedure and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to identify and quantify dimethoate, omethoate, dichlorvos, carbofuran, fenpropathrin, diazepam, estazolam, alprazolam, triazolamm, chlorpromazine, phenergan, barbitone and phenobarbital in human blood. The method demonstrated a linear calibration curve in range of 20 - 500 μg/L (r > 0.994). The accuracy evaluated by recovery spiked at three different concentrations (50, 100 and 200 μg/L) was in the range of 58.8 - 83.1% with a relative standard deviations (RSD) of 3.7 - 7.4%. The limits of quantification ranged over 6.7 - 33.3 μg/L. This method was proved to be simple and reliable, and was thus successfully applied to forensic toxicology. PMID:27302585

  4. Dispersive Liquid-Liquid Microextraction Combined with Ultrahigh Performance Liquid Chromatography/Tandem Mass Spectrometry for Determination of Organophosphate Esters in Aqueous Samples

    PubMed Central

    Luo, Haiying; Xian, Yanping; Guo, Xindong; Luo, Donghui; Lu, Yujing; Yang, Bao

    2014-01-01

    A new technique was established to identify eight organophosphate esters (OPEs) in this work. It utilised dispersive liquid-liquid microextraction in combination with ultrahigh performance liquid chromatography/tandem mass spectrometry. The type and volume of extraction solvents, dispersion agent, and amount of NaCl were optimized. The target analytes were detected in the range of 1.0–200 µg/L with correlation coefficients ranging from 0.9982 to 0.9998, and the detection limits of the analytes were ranged from 0.02 to 0.07 µg/L (S/N = 3). The feasibility of this method was demonstrated by identifying OPEs in aqueous samples that exhibited spiked recoveries, which ranged between 48.7% and 58.3% for triethyl phosphate (TEP) as well as between 85.9% and 113% for the other OPEs. The precision was ranged from 3.2% to 9.3% (n = 6), and the interprecision was ranged from 2.6% to 12.3% (n = 5). Only 2 of the 12 selected samples were tested to be positive for OPEs, and the total concentrations of OPEs in them were 1.1 and 1.6 µg/L, respectively. This method was confirmed to be simple, fast, and accurate for identifying OPEs in aqueous samples. PMID:24616613

  5. [Determination of capsaicinoids and eugenol in waste-edible-oil by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry].

    PubMed

    Zhang, Zhong; Ren, Fei; Zhang, Pan

    2012-11-01

    A method was developed for the determination of capsaicinoids (capsaicin, dihydrocapsaicin and synthetic capsaicin) and eugenol in waste-edible-oil extracted by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The capsaicinoids and eugenol in waste-edible-oil were extracted by methanol, and then separated by a SUPEL COSIL ABZ + Plus dC18 column (150 mm x4.6 mm, 5 microm). The analysis was performed by MS/MS with electrospray ionization in positive and negative ion modes with multiple reaction monitoring (MRM). The limits of detection for capsaicin, dihydrocapsaicin, synthetic capsaicin and eugenol were 0.02, 0.03, 0.03 and 0.6 microg/L, respectively. The good linear relationships were obtained in certain concentration ranges of capsaicinoids and eugenol. The relative standard deviations (RSDs, n=5) of same-worker and different-worker were less than 5%. The method is exclusive, sensitive and accurate, and can be used in waste-edible-oil determination. PMID:23451511

  6. Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry

    PubMed Central

    Koop, Dennis R.; Bleyle, Lisa A.; Munar, Myrna; Cherala, Ganesh; Al-Uzri, Amira

    2014-01-01

    Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC–MS/MS). Tacrolimus and creatinine were extracted from a 6 mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 μl aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from −4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from −2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories. PMID:23548676

  7. Potential of atmospheric pressure chemical ionization source in gas chromatography tandem mass spectrometry for the screening of urinary exogenous androgenic anabolic steroids.

    PubMed

    Raro, M; Portolés, T; Pitarch, E; Sancho, J V; Hernández, F; Garrostas, L; Marcos, J; Ventura, R; Segura, J; Pozo, O J

    2016-02-01

    The atmospheric pressure chemical ionization (APCI) source for gas chromatography-mass spectrometry analysis has been evaluated for the screening of 16 exogenous androgenic anabolic steroids (AAS) in urine. The sample treatment is based on the strategy currently applied in doping control laboratories i.e. enzymatic hydrolysis, liquid-liquid extraction (LLE) and derivatization to form the trimethylsilyl ether-trimethylsilyl enol ether (TMS) derivatives. These TMS derivatives are then analyzed by gas chromatography tandem mass spectrometry using a triple quadrupole instrument (GC-QqQ MS/MS) under selected reaction monitoring (SRM) mode. The APCI promotes soft ionization with very little fragmentation resulting, in most cases, in abundant [M + H](+) or [M + H-2TMSOH](+) ions, which can be chosen as precursor ions for the SRM transitions, improving in this way the selectivity and sensitivity of the method. Specificity of the transitions is also of great relevance, as the presence of endogenous compounds can affect the measurements when using the most abundant ions. The method has been qualitatively validated by spiking six different urine samples at two concentration levels each. Precision was generally satisfactory with RSD values below 25 and 15% at the low and high concentration level, respectively. Most the limits of detection (LOD) were below 0.5 ng mL(-1). Validation results were compared with the commonly used method based on the electron ionization (EI) source. EI analysis was found to be slightly more repeatable whereas lower LODs were found for APCI. In addition, the applicability of the developed method has been tested in samples collected after the administration of 4-chloromethandienone. The highest sensitivity of the APCI method for this compound, allowed to increase the period in which its administration can be detected. PMID:26772132

  8. Analysis of quinolone antibiotic derivatives in sewage sludge samples by liquid chromatography-tandem mass spectrometry: comparison of the efficiency of three extraction techniques.

    PubMed

    Dorival-García, N; Zafra-Gómez, A; Camino-Sánchez, F J; Navalón, A; Vílchez, J L

    2013-03-15

    This work presents a comparison of three extraction techniques -ultrasound-assisted extraction (USE), microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) - and evaluates their efficiency in the determination of quinolone antibiotics in sewage sludge samples. Extraction parameters for each technique were optimized using design of experiments, and the compounds were detected and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS), operating in positive electrospray ionization (ESI) mode. The use of two selected reaction monitoring transitions for each compound allowed simultaneous quantification and identification in one run. Analytes were separated in less than 10 min. Marbofloxacin and cincophen were used as surrogates for amphoteric and acid quinolones, respectively. The limits of detection (LODs) were between 2 and 5 ng g(-1), and the limits of quantification (LOQs) were between 4 and 18 ng g(-1) for the various analytes. The inter- and intra-day variability was <7%. Due to the absence of certified reference materials (CRMs), the method was validated using matrix-matched calibration and a recovery assay with spiked samples. Recovery rates were between 97.9% and 104.8%. Statistical comparison demonstrated no significant differences between the three extraction techniques. The methods were successfully applied for the determination of quinolones in sewage sludge samples collected from different wastewater treatments plants (WWTPs) located in the province of Granada (Spain). The analytical methods developed here may be useful for the development of more in-depth studies on the occurrence and fate of these commonly used pharmaceuticals in WWTPs and in the environment. PMID:23598102

  9. Leukotriene-E4 in human urine: Comparison of on-line purification and liquid chromatography-tandem mass spectrometry to affinity purification followed by enzyme immunoassay.

    PubMed Central

    Armstrong, Michael; Liu, Andrew H.; Harbeck, Ronald; Reisdorph, Rick; Rabinovitch, Nathan; Reisdorph, Nichole

    2009-01-01

    A new analytical method suitable for high throughput measurements of LTE4 in human urine is described. The methodology utilizes on-line enrichment and liquid chromatography/ tandem mass spectrometry (LC/MS/MS). The novel LC/MS/MS method is rapid, linear from 5 to 500 pg/mL in spiked urine samples of both healthy and asthmatic subjects and more accurate and precise than enzyme immunoassay (EIA) and previous LC/MS/MS methods. Results from sample integrity experiments and preliminary values of urinary LTE4 from healthy adults and children are reported. PMID:19726242

  10. Ultra performance liquid chromatography tandem mass spectrometry assay for determination of kukoamine B in human blood and urine.

    PubMed

    Zhao, Qian; Li, Lili; Wang, Zhenlei; Jiang, Ji; Dong, Kai; Chen, Shuai; Hu, Pei

    2016-09-15

    In this paper, we report a sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method which is capable of quantifying kukoamine B (KB) levels in human blood and urine. Following solid phase extraction and direct dilution process, the analyte and its internal standard (D5-KB) run on an Acquity UPLC(®) HSS T3 column (2.1×50mm i.d., 1.8μm) by using a gradient elution method (run time was 1.5min). The mass spectrometric analysis was performed by using an API-5500 mass spectrometer coupled with an electro-spray ionization source. The MRM transitions of m/z 531.3(+)→222.1(+) and 536.3(+)→222.1(+) were used to quantify KB and D5-KB respectively. This assay method has been fully validated in terms of selectivity, linearity, lower limit of quantification, precision, accuracy, stability, recovery and matrix effect. The concentration range of this method is 10.0-2000.0ngmL(-1) in blood and 0.5-500.0ngmL(-1) in urine. Linearity (R(2)) of calibration curves were 0.9964±0.0022 and 0.9935±0.0053 for blood and urine, respectively (regression equation: y=ax+b). The precision (RSD%) of quality control samples is less than 10.3% for blood and less than 10.5% for urine. The accuracy (RE%) is within -4.0-11.3% and -11.7-12.5% for blood and urine respectively. KB was stable after 4h in ice-water bath, 1 freeze/thaw cycles and 180days at -80°C for blood samples; and was stable after 3h at room temperature, 3 freeze/thaw cycles and 180days at -80°C for urine samples. Recoveries of KB were 4.7±0.9% in blood and 96.5±1.3% in urine, respectively. Additionally, the applicability of this method has been proved by analyzing clinical samples from pharmacokinetic study of KB in human. PMID:27447928

  11. Rapid determination of benzodiazepines, zolpidem and their metabolites in urine using direct injection liquid chromatography-tandem mass spectrometry.

    PubMed

    Jeong, Yu-Dong; Kim, Min Kyung; Suh, Sung Ill; In, Moon Kyo; Kim, Jin Young; Paeng, Ki-Jung

    2015-12-01

    Benzodiazepines and zolpidem are generally prescribed as sedative, hypnotics, anxiolytics or anticonvulsants. These drugs, however, are frequently misused in drug-facilitated crime. Therefore, a rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of benzodiazepines, zolpidem and their metabolites in urine using deuterium labeled internal standards (IS). Urine samples (120 μL) mixed with 80 μL of the IS solution were centrifuged. An aliquot (5 μL) of the sample solution was directly injected into the LC-MS/MS system for analysis. The mobile phases consisted of water and acetonitrile containing 2mM ammonium trifluoroacetate and 0.2% acetic acid. The analytical column was a Zorbax SB-C18 (100 mm × 2.1 mm i.d., 3.5 μm, Agilent). The separation and detection of 18 analytes were achieved within 10 min. Calibration curves were linear over the concentration ranges of 0.5-20 ng/mL (zolpidem), 1.0-40 ng/mL (flurazepam and temazepam), 2.5-100 ng/mL (7-aminoclonazepam, 1-hydroxymidazolam, midazolam, flunitrazepam and alprazolam), 5.0-200 ng/mL (zolpidem phenyl-4-carboxylic acid, α-hydroxyalprazolam, oxazepam, nordiazepam, triazolam, diazepam and α-hydroxytriazolam), 10-400 ng/mL (lorazepam and desalkylflurazepam) and 10-100 ng/mL (N-desmethylflunitrazepam) with the coefficients of determination (r(2)) above 0.9971. The dilution integrity of the analytes was examined for supplementation of short linear range. Dilution precision and accuracy were tested using two, four and ten-folds dilutions and they ranged from 3.7 to 14.4% and -12.8 to 12.5%, respectively. The process efficiency for this method was 63.0-104.6%. Intra- and inter-day precisions were less than 11.8% and 9.1%, while intra- and inter-day accuracies were less than -10.0 to 8.2%, respectively. The lower limits of quantification were lower than 10 ng/mL for each analyte. The applicability of the developed method was successfully

  12. Determination of methamphetamine enantiomer composition in human hair by non-chiral liquid chromatography-tandem mass spectrometry method.

    PubMed

    Shu, Irene; Alexander, Amy; Jones, Mary; Jones, Joseph; Negrusz, Adam

    2016-08-15

    Chiral separation is crucial for investigating methamphetamine positive cases. While (S)-(+)-enantiomer of methamphetamine (S-MAMP) is a schedule II controlled substance, (R)-(-)-enantiomer (R-MAMP) is an active ingredient of a few over-the-counter drugs in the United States. Among biological specimen types, hair provides greater detection window than blood, urine or oral fluid, and are therefore regarded with particular interest. Herein we describe a novel non-chiral liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to directly determine methamphetamine enantiomeric composition (percentage) in hair specimens. Hair samples were washed once with acetone, powdered, incubated overnight at 53°C in 0.1M hydrochloric acid (HCl), and subjected to a solid phase extraction (SPE). The extracts were derivatized using Marfey's reagent at 53°C for 60min. The final mixture was analyzed by LC-MS/MS. Chromatographic separation was achieved using a C18 Kinetex analytical column and 60% (v/v) aqueous methanol as mobile phase (isocratic). Triple quadrupole mass spectrometer was equipped with an electro-spray ionization (ESI) source operating in negative mode and the chromatograms were acquired using a multiple-reaction monitoring (MRM) approach. The results were expressed as ratio of R- to S-MAMP and then derived to composition percentages without requiring quantitating each enantiomer. The method was precise and accurate across 0-100% S-composition at a range of 80-18,000pg/mg. The performance of the new method was compared with an (S)-(-)-N-trifluoroacetylprolyl chloride (S-TPC) derivatization and gas chromatography-mass spectrometry (GC-MS) method on authentic methamphetamine-positive hair samples. Not only the new Marfey's reagent approach presented satisfactory correlation with the S-TPC approach, but it also exhibited significantly improved quality (e.g., S/N) of the chromatograms. In summary, our protocol employs cost effective and minimally hazardous Marfey

  13. Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry

    PubMed Central

    Faqehi, Abdullah M.M.; Cobice, Diego F.; Naredo, Gregorio; Mak, Tracy C.S.; Upreti, Rita; Gibb, Fraser W.; Beckett, Geoffrey J.; Walker, Brian R.; Homer, Natalie Z.M.; Andrew, Ruth

    2016-01-01

    Estrogens circulate at concentrations less than 20 pg/mL in men and postmenopausal women, presenting analytical challenges. Quantitation by immunoassay is unreliable at these low concentrations. Liquid chromatography tandem mass spectrometry (LC–MS/MS) offers greater specificity and sometimes greater sensitivity, but ionization of estrogens is inefficient. Introduction of charged moieties may enhance ionization, but many such derivatives of estrogens generate non-specific product ions originating from the “reagent” group. Therefore an approach generating derivatives with product ions specific to individual estrogens was sought. Estrogens were extracted from human plasma and serum using solid phase extraction and derivatized using 2-fluoro-1-methylpyridinium-p-toluenesulfonate (FMP-TS). Electrospray in positive mode with multiple reaction monitoring using a QTrap 5500 mass spectrometer was used to quantify “FMP” derivatives of estrogens, following LC separation. Transitions for the FMP derivatives of estrone (E1) and estradiol (E2) were compound specific (m/z 362→238 and m/z 364→128, respectively). The limits of detection and quantitation were 0.2 pg on-column and the method was linear from 1–400 pg/sample. Measures of intra- and inter-assay variability, precision and accuracy were acceptable (<20%). The derivatives were stable over 24 h at 10 °C (7–9% degradation). Using this approach, E1 and E2, respectively were detected in human plasma and serum: pre-menopausal female serum (0.5 mL) 135–473, 193–722 pmol/L; male plasma (1 mL) 25–111, 60–180 pmol/L and post-menopausal female plasma (2 mL), 22–78, 29–50 pmol/L. Thus FMP derivatization, in conjunction with LC–MS/MS, is suitable for quantitative analysis of estrogens in low abundance in plasma and serum, offering advantages in specificity over immunoassay and existing MS techniques. PMID:26946022

  14. Determination of perfluorinated compounds in mollusks by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

    PubMed

    Villaverde-de-Sáa, Eugenia; Quintana, José Benito; Rodil, Rosario; Ferrero-Refojos, Raúl; Rubí, Elisa; Cela, Rafael

    2012-01-01

    Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of eight PFCs in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simplicity of the analytical procedure, low volume of solvent and quantity of sample required, low global price, and integration of extraction and clean-up into a single step, are the most important advantages of the developed methodology. Solvent, solid support (dispersing agent), clean-up sorbent, and their amounts were optimized by means of an experimental design. In the final method, 0.5 g of sample are dispersed with 0.2 g of diatomaceous earth and transferred into a polypropylene syringe containing 4 g of silica as clean-up sorbent. Then, analytes are eluted with 20 mL of acetonitrile. The extract is finally concentrated to a final volume of 0.5 mL in methanol, avoiding extract dryness in order to prevent evaporation losses and injected in the LC-MS/MS. The combination of this MSPD protocol with LC-MS/MS afforded detection limits from 0.05 to 0.3 ng g(-1). Also, a good linearity was established for the eight PFCs in the range from limit of quantification (LOQ) to 500 ng mL(-1) with R(2) > 0.9917. The recovery of the method was studied with three types of spiked mollusk and was in the 64-126% range. Moreover, a mussel sample was spiked and aged for more than 1 month and analyzed by the developed method and a reference method, ion-pair extraction, for comparison, producing both methods statistically equal concentration values. The method was finally applied to the determination of PFCs in different kinds of mollusks revealing concentrations up to 8.3 ng g(-1) for

  15. Fast liquid chromatography/tandem mass spectrometry determination of cannabinoids in micro volume blood samples after dabsyl derivatization.

    PubMed

    Lacroix, C; Saussereau, E

    2012-09-15

    Due to the non-polar nature and the absence of an ionizable group on the cannabinoids, the ionization efficiency in electrospray is low and leads to poor limits of detection (LOD). The reaction of chloride dabsyl with the phenolic OH group of cannabinoids results in a product containing a tertiary amine, which is easily protonated in positive electrospray mode and can significantly improve the cannabinoids LOD. A rapid, selective and sensitive LC/MS-MS method was developed for quantitative determination of Δ(9)-tetrahydrocannabinol (THC), 11-hydroxy-Δ(9)-tetrahydrocannabinol (11-OH-THC), 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH), cannabinol (CBN) and cannabidiol (CBD), in micro volume blood samples following dabsyl derivatization to enhance signal intensity. The method comprised protein precipitation followed by derivatization with dabsyl chloride and subsequent analysis using liquid chromatography-tandem mass spectrometry (LC/MS-MS). Chromatographic separation was achieved using a 150 mm × 2.1 mm C18 analytical column maintained at 65°C and eluted with a gradient of water and acetonitrile, both containing 0.2% formic acid. The run time was 8 min. The assay was successfully validated using the approach based on the accuracy profile. Lower limits of quantification (LOQ) were 0.25 ng/mL for THC and THC-COOH, 0.30 ng/mL for 11-OH-THC, 0.40 ng/mL for CBN and 0.80 ng/mL for CBD. A comparative study of cannabinoids in blood and plasma, as determined by the developed LC/MS-MS method or the in-house GC/MS-MS technique, demonstrated an excellent correlation between the two methods. Dabsylation was also tested on-line with a spiral of peek tubing placed in the LC/MS-MS column heater at 65°C before the analytical column. The results obtained with on-line dabsyl derivatization were similar to those observed off-line. PMID:22921635

  16. Class-specific molecularly imprinted polymers for the selective extraction and determination of sulfonylurea herbicides in maize samples by high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    She, Yong-Xin; Cao, Wei-Qiang; Shi, Xiao-Mei; Lv, Xiao-Ling; Liu, Jia-Jia; Wang, Rong-Yan; Jin, Fen; Wang, Jing; Xiao, Hang

    2010-08-01

    A novel method based on the molecularly imprinted solid-phase extraction (MISPE) procedure has been developed for the simultaneous determination of concentrations of sulfonylurea herbicides such as chlorsulfuron (CS), monosulfuron (MNS), and thifensulfuron methyl (TFM) in maize samples by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). The molecularly imprinted polymer (MIP) for sulfonylurea herbicides was synthesized by precipitation polymerization using chlorsulfuron as the template molecule, 2-(diethylamino)ethyl methacrylate (DEAMA) as the functional monomer, and trimethylolpropane trimethacrylate (TRIM) as the cross-linker. The selectivities of the chlorsulfuron template and its analogs on the molecularly imprinted polymer were evaluated by high-performance liquid chromatography (HPLC). The extraction and purification procedures for the solid-phase extraction (SPE) cartridge with a molecularly imprinted polymer as the adsorbent for the selected sulfonylurea herbicides were then established. A molecularly imprinted solid-phase extraction method followed by high-performance liquid chromatography-tandem mass spectrometry for the determination of chlorsulfuron, monosulfuron, and thifensulfuron methyl was also established. The mean recoveries of these compounds in maize were in the range 75-110% and the limits of detection (LOD) of chlorsulfuron, monosulfuron, and thifensulfuron methyl were 0.02, 0.75, and 1.45 microg kg(-1), respectively. It was demonstrated that the MISPE-HPLC-MS/MS method could be applied to the determination of chlorsulfuron, monosulfuron, and thifensulfuron methyl in maize samples. PMID:20598653

  17. Simultaneous determination of Δ9-tetrahydrocannabinol, cannabidiol, cannabinol and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in hair using liquid chromatography-tandem mass spectrometry.

    PubMed

    Dulaurent, S; Gaulier, J M; Imbert, L; Morla, A; Lachâtre, G

    2014-03-01

    For several years, hair analyses have become a powerful tool to investigate past exposure towards xenobiotics. In the case of illicit drugs and more precisely of cannabis exposure, four compounds are usually investigated: Δ(9)-tetrahydrocannabinol (THC), the main active compound of cannabis, one of its metabolites [11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH)] and two cannabinoids (cannabinol and cannabidiol). Up until now, the hair determination of the carboxylic metabolite of THC, which has been described as the only marker allowing distinguishing consumption and passive exposure, has been performed using a gas chromatography-tandem mass spectrometry method. The aim of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitative determination of the four markers. The sample preparation was based on an alkaline hydrolysis of hair samples followed by a liquid-liquid extraction of compounds in acidic conditions using a hexane/ethyl acetate mixture. The method was validated and the results were satisfactory: intra- and inter-assay accuracies below 9% and relative standard deviation below 15% for the four compounds. Moreover, the limit of quantification for THC-COOH, the most challenging compound, was validated at 0.2 pg/mg. This concentration is in accordance with the recommendations made by a scientific society which specializes in hair testing. It makes it possible to distinguish the kind of exposure to cannabis. PMID:24529787

  18. Determination of very low stable isotope enrichments of [(2)H(5)]-phenylalanine in chicken liver using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Wilkerling, Katrin; Valenta, Hana; Kersten, Susanne; Dänicke, Sven

    2012-12-12

    Stable isotope labeled amino acids are frequently used to examine nutritive effects on protein synthesis. This technique is characterized by tracing the incorporation of the label into newly synthesized proteins. In the present investigation, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of very low enrichment of protein-bound l-[(2)H(5)]-phenylalanine ([(2)H(5)]-phe) in chicken liver. The LC-MS/MS measurements were carried out in positive atmospheric pressure chemical ionization (APCI) mode. Two mass transitions each for [(2)H(5)]-phe (171.1/125.1 and 171.1/106.1) and l-phenylalanine (phe) (166.1/91.1 and 166.1/93.1) were chosen for quantification and qualification. Due to the high excesses of phe, less sensitive transitions were chosen in the case of phe. The separation was carried out on a phenyl-hexyl column using 0.1% formic acid as eluent A and methanol as eluent B. The method was calibrated with calibration standard solutions in the range of 0.01-0.5 mole percent excess (MPE). Linear regression analysis led to coefficients of determination (r(2)) greater than 0.9995. The method was applied on liver samples from experiments investigating nutritive effects on tissue protein synthesis in broiler chickens. These samples were analyzed with a gas chromatography-mass spectrometry (GC-MS) method and reanalyzed with the developed LC-MS/MS method one year later. Compared to GC-MS, the main advantages of the LC-MS/MS method are its higher selectivity as well as the elimination of the need to convert and derivatize the samples prior to measuring. PMID:23217318

  19. ANALYSIS OF THE FLAME RETARDANT METABOLITES BIS (1,3-DICHLORO-2-PROPYL) PHOSPHATE (BDCPP) AND DIPHENYL PHOSPHATE (DPP) IN URINE USING LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

    PubMed Central

    Cooper, EM; Covaci, A; van Nuijs, ALN; Webster, TF; Stapleton, HM

    2013-01-01

    Organophosphate triesters tris-(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) are widely used flame retardants (FRs) present in many products common to human environments, yet understanding of human exposure, and health effects of these compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding; however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis (1,3-dichloro-2-propyl) phosphate (BDCPP), in human urine. Here we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP) in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry (APCI-LC/MS-MS). The method detection limit was 8 pg mL−1 urine for BDCPP and 204 pg mL−1 for DPP. Recoveries of analytes spiked into urine ranged from 82 ± 10% to 91 ± 4% for BDCPP and from 72 ± 12% to 76 ± 8% for DPP. Analysis of a small number of urine samples (n=9) randomly collected from non occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples. Non-normalized urinary concentrations ranged from 46–1662 pg BDCPP mL−1 and 287–7443 pg DPP mL−1, with geometric means of 147 pg BDCPP mL−1 and 1074 pg DPP mL−1. Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure and potential health effects to FRs. PMID:21830137

  20. Using total error concept for the validation of a liquid chromatography-tandem mass spectrometry method for the determination of budesonide epimers in human plasma.

    PubMed

    Streel, B; Cahay, B; Klinkenberg, R

    2009-08-01

    A robust, sensitive and selective method to quantify budesonide epimers in human plasma using solid-phase extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. The drug was first isolated from the biological matrix by automated solid-phase extraction (SPE) on disposable extraction cartridges (C-2). The methanolic eluate was then collected and evaporated to dryness. The residue was dissolved in mobile phase and an aliquot was injected onto a Phenomenex Luna octadecylsilica (C-18) column (50 mm x 4.6 mm i.d., 3 microm). The mobile phase is composed of water containing 10 mM ammonium acetate adjusted to pH 3.2 with glacial acetic acid and acetonitrile (65:35, v/v). The flow-rate was 1.00 ml/min. Hydrocortisone acetate was used as internal standard (IS). Detection of the analytes was achieved using negative atmospheric pressure chemical ionization (APCI) tandem mass spectrometry in selected reaction monitoring (SRM) mode. The MS/MS ion transitions monitored were m/z 489.3-->357.3 and 463.3-->403.2 for budesonide epimers and hydrocortisone, respectively. The method was validated using SFSTP (2003) proposal based on total measurement error and accuracy profiles as a decision tool. The most appropriate regression model for the response function as well as the limit of quantitation was first selected during the prevalidation step. These latter criteria were then assessed during the formal validation step. The limit of quantitation (LOQ) was around 50 pg/ml for budesonide epimers. The method was validated with respect to stability, recovery, linearity, precision, trueness and accuracy. Risk and uncertainty were also evaluated. The validated method was finally applied successfully to investigate the plasma concentration of budesonide epimers in a pharmacokinetic study. PMID:19249257

  1. Pharmacokinetic studies of phellodendrine in rat plasma and tissues after intravenous administration using ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Li, Yi; Liu, Xin-Guang; Wang, Hui-Ying; Dong, Xin; Gao, Wen; Xu, Xiao-Jun; Li, Ping; Yang, Hua

    2016-09-01

    Phellodendrine, a quaternary ammonium alkaloid extracted from the dried bark of Phellodendrom chinensis Schneid and Phellodendrom amurense Rupr, has the effect of suppressing cellular immune response, reducing blood pressure and antinephritis. However, few investigations have been conducted for the pharmacokinetic study of phellodendrine. Thus, a rapid, simple and reliable ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry (UHPLC-QQQ MS/MS) method has been established for quantification of phellodendrine in rat plasma and tissues by using magnoflorine as internal standard. The chromatographic separation was achieved on an Agilent ZORBAX SB-C18 column (4.6mm×50mm, 1.8μm) by gradient elution using 0.1% aqueous formic acid (A) and methanol (B). Triple quadrupole mass detection with multiple reaction monitoring mode was used to monitor the ion transitions, at m/z 342.20→192.20 for phellodendrine and m/z 342.20→58.20 for internal standard, respectively. The developed method was fully validated and successfully applied to the pharmacokinetics and tissue distribution study of phellodendrine after intravenous administration. The lower limits of quantification were 0.5ng/mL for plasma samples, 2.5ng/g for brain and 1ng/g for other tested tissues. Precisions and accuracy values were within the Food and Drug Administration acceptance criteria, the recovery and matrix effects were between 87.8-113.5%. The area under the curve (AUC0-t) ranged from 15.58 to 57.41mg/L min and Cmax were between 1.63-4.93mg/L. The results showed that phellodendrine was eliminated in 120min in plasma and most of tissues and the highest concentrations of phellodendrine were found in the kidney. This study may provide a basis for the further study of phellodendrine. PMID:27428451

  2. Analysis of the flame retardant metabolites bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPP) in urine using liquid chromatography-tandem mass spectrometry.

    PubMed

    Cooper, E M; Covaci, A; van Nuijs, A L N; Webster, T F; Stapleton, H M

    2011-10-01

    Organophosphate triesters tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate are widely used flame retardants (FRs) present in many products common to human environments, yet understanding of human exposure and health effects of these compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding; however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), in human urine. Here, we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP) in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry. The method detection limit was 8 pg mL(-1) urine for BDCPP and 204 pg mL(-1) for DPP. Recoveries of analytes spiked into urine ranged from 82 ± 10% to 91 ± 4% for BDCPP and from 72 ± 12% to 76 ± 8% for DPP. Analysis of a small number of urine samples (n=9) randomly collected from non-occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples. Non-normalized urinary concentrations ranged from 46-1,662 pg BDCPP mL(-1) to 287-7,443 pg DPP mL(-1), with geometric means of 147 pg BDCPP mL(-1) and 1,074 pg DPP mL(-1). Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure to and potential health effects from FRs. PMID:21830137

  3. [Determination of 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk by liquid chromatography-tandem mass spectromtery].

    PubMed

    Wang, Hao; Zhao, Li; Yang, Hongmei; Pan, Hongyan; Shi, Hailiang; Qian, Cong; Zhang, Shan

    2015-09-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the simultaneous determination of 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk. The samples were extracted with alkaline acetonitrile and McIlvaine buffer solution under ultrasonication. The separation of target compounds was performed on an Eclipse XDB-C, column (150 mm x 2.1 mm, 3.5 µm) with gradient elution at a flow rate of 0.25 mL/min, and with an injection volume of 10 µL. The identification and quantification of the compounds were completed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring ( MRM) mode. The limits of detection were all below 10.0 µg/kg. The average spiked recoveries of the method ranged from 70. 1% to 109. 9% with relative standard deviations (RSDs) of 2.89%-9.99%. After validation, the method was applied to the analysis of antibiotic residues in milk products in China. Fifty samples were screened under the well defined methodology, and the results showed that chloramphenicol, only in one sample, was monitored with the content of 0.48 µg/kg. A risk of contamination of milk with chloramphenicol has been determined to exist. Therefore this method is convenient, rapid, sensitive and reliable, and can be successfully applied to the simultaneous detection of the 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk. PMID:26753289

  4. Application of dispersive liquid-liquid microextraction for the determination of phosphatidylethanol in blood by liquid chromatography tandem mass spectrometry.

    PubMed

    Cabarcos, Pamela; Ángel Cocho, José; Moreda, Antonio; Míguez, Martha; Jesús Tabernero, María; Fernández, Purificación; María Bermejo, Ana

    2013-07-15

    Phosphatidylethanol (PEth) is a phospholipid which requires for its metabolic formation the presence of relatively high ethanol levels. PEth is thus a promising marker to quentify ethanol abuse. Dispersive liquid-liquid microextraction has become a popular technique because it is fast, inexpensive, easy to operate and consumes low volume of organic solvent. In this method, the appropriate mixture of extraction solvent (230 μL dichloromethane) and disperser solvent (630 μL acetone) are injected into the sample by syringe, rapidly. The liquid chromatography method using a reversed phase-C8 column and a negative ion mode electrospray ionization tandem mass spectrometry detection instrument was developed for the determination of small amounts of PEth that might be present in blood samples, using phosphatidylbutanol (PBut) as an internal standard. The sensitivity of detection obtained with tandem MS was better than that of previous methods. Good linearity was obtained for a range of LOQ-10 μg/mL for PEth, whereas all of the deviations in precision and accuracy were less than 15% except for the LLOQ, where it should not exceed 20%. A set of 50 blood samples were analyzed by such method and whole blood concentrations of PEth 16:0/18:1 ranged from LLOQ to 1.71 μg/mL. PMID:23622544

  5. Data supporting the rat brain sample preparation and validation assays for simultaneous determination of 8 neurotransmitters and their metabolites using liquid chromatography-tandem mass spectrometry.

    PubMed

    Wojnicz, Aneta; Ortiz, José Avendaño; Casas, Ana I; Freitas, Andiara E; López, Manuela G; Ruiz-Nuño, Ana

    2016-06-01

    The data presented in this article supports the rat brain sample preparation procedure previous to its injection into the liquid chromatography-tandem mass spectrometry (LC-MS/MS) system to monitor levels of adrenaline, noradrenaline, glutamic acid, γ-aminobutyric acid, dopamine, 5-hydroxytryptamine, 5-hydroxyindole acetic acid, and 3-methoxy-4-hydroxyphenylglycol. In addition, we describe the method validation assays (such as calibration curve, lower limit of quantification, precision and accuracy intra- and inter-day, selectivity, extraction recovery and matrix effect, stability, and carry-over effect) according to the United States Food and Drug Administration and European Medicine Agency to measure in one step different neurotransmitters and their metabolites. The data supplied in this article is related to the research study entitled: "Simultaneous determination of 8 neurotransmitters and their metabolite levels in rat brain using liquid chromatography in tandem with mass spectrometry: application to the murine Nrf2 model of depression" (Wojnicz et al. 2016) [1]. PMID:27054183

  6. Automated hollow-fiber liquid-phase microextraction coupled with liquid chromatography/tandem mass spectrometry for the analysis of aflatoxin M₁ in milk.

    PubMed

    Huang, Siming; Hu, Du; Wang, Ying; Zhu, Fang; Jiang, Ruifen; Ouyang, Gangfeng

    2015-10-16

    An automated hollow fiber liquid-phase microextraction (HF-LPME) coupled with liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the extraction and determination of aflatoxin M1 (AFM1) in milk samples. Parameters affecting the extraction efficiency, such as the extraction phase, matrix conditions, extraction time and temperature, were investigated. Under the optimal conditions (ratio of water to milk, 4:1; extraction time, 50 min; extraction temperature, 50°C; extraction phase, 50 mg L(-1) anti-AFM1 antibody in PBS buffer solution; volume of HCl solution, 250 μL; agitation speed, 250 rpm), the matrix-matched calibration curve for AFM1 determination showed good linearity in the range of 0.25-5 μg kg(-1). The enrichment factor (EF) reached 48, and the limits of detection and quantification were 0.06 and 0.21 μg kg(-1), respectively. The developed method was successfully applied for the extraction of AFM1 from spiked milk samples, with recoveries from 61.0% to 106.7%. The method was highly specific to AFM1 analysis, and the results demonstrated that the method can be automated, inexpensive, and free from interference. PMID:26365912

  7. Pharmaceuticals in the freshwater invertebrate, Gammarus pulex, determined using pulverised liquid extraction, solid phase extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Miller, Thomas H; McEneff, Gillian L; Brown, Rebecca J; Owen, Stewart F; Bury, Nicolas R; Barron, Leon P

    2015-04-01

    The development, characterisation and application of a new analytical method for multi-residue PPCP determination in the freshwater amphipod, Gammarus pulex are presented. Analysis was performed using pulverised liquid extraction (PuLE), solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Qualitative method performance offered excellent limits of detection at <20 ng g(-1) for 18 out of 29 compounds. For quantitative application, linearity and precision were considered acceptable for 10 compounds across the ng-μg g(-1) range (R2≥0.99; ≤20% relative standard deviation respectively). The method was applied to the analysis of G. pulex and river water sourced from six tributaries of the River Thames. Carbamazepine, diazepam, nimesulide, trimethoprim and warfarin were determined in G. pulex samples at low ng g(-1) (dry weight) concentrations across these sites. Temazepam and diclofenac were also detected, but were not quantifiable. Six pharmaceuticals were quantified in surface waters across the eight sites at concentrations ranging from 3 to 344 ng L(-1). The possibility for confirmatory detection and subsequent quantification of pharmaceutical residues in benthic organisms such as G. pulex will enable further understanding on the susceptibility and ecological effects of PPCPs in the aquatic environment. PMID:25544334

  8. Simultaneous determination of polycyclic musks in blood and urine by solid supported liquid-liquid extraction and gas chromatography-tandem mass spectrometry.

    PubMed

    Liu, Hongtao; Huang, Liping; Chen, Yuxin; Guo, Liman; Li, Limin; Zhou, Haiyun; Luan, Tiangang

    2015-06-15

    A rapid, precise and accurate method for the simultaneous determination of 5 polycyclic musks (PCMs) in biological fluids was developed by solid supported liquid-liquid extraction (SLE) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS). All parameters influencing SLE-GC-MS performance, including electron energy of electron-impact ionization source, collision energy for tandem mass spectrometer when operated in selected-reaction monitoring (SRM) mode, type and volume of elution reagent, nitrogen evaporation time, pH and salinity of sample have been carefully optimized. Eight milliliter of n-hexane was finally chosen as elution reagent. Blood and urine sample could be loaded into SLE cartridge without adjusting pH and salinity. Deuterated tonalide (AHTN-d3) was chosen as internal standard. The correlation coefficient (r(2)) of the calibration curves of target compounds ranged from 0.9996 to 0.9998. The dynamic range spanned over two orders of magnitude. The limit of detection (LOD) of target compounds in blood and urine ranged from 0.008 to 0.105μgL(-1) and 0.005 to 0.075μgL(-1), respectively. The developed procedure was successfully applied to the analysis of PCMs in human blood and urine obtaining satisfying recoveries on low, medium and high levels. The method was compared with SLE-GC-MS and shown one to two orders of magnitude improvement in sensitivity. PMID:25965876

  9. Determination of Earthy-musty Odorous Compounds in Drinking Water by Vortex Assisted Dispersive Liquid-Liquid Microextraction Combined with Gas Chromatography Tandem Mass Spectrometry.

    PubMed

    Lu, Jian; Wu, Zhong-Ping; Che, Wen-Jun; Xian, Yan-Ping; Guo, Xin-Dong; Lv, Jia-Xin; Li, He

    2016-01-01

    A new method was developed for the determination of eight earthy-musty compounds in drinking water by gas chromatography tandem mass spectrometry (GC-MS/MS) combined with dispersive liquid-liquid microextraction (DLLME). In this work, the type and volume of extraction solvent and dispersion agent, and the amount of NaCl were optimized; the linearity, detection limit, recovery and precision of method were investigated. The results indicated that the target analytes were in the range of 0.2 - 100 μg/L with correlation coefficient (r) ranging from 0.9991 to 0.9999, the limit of detection (LOD, S/N = 3) of the analytes ranged from 0.2 to 1.0 ng/L with the enrichment factor of 320. The mean recoveries for drinking water at three spiked concentrations levels of 0.6 - 32 ng/L were in the range of 91.3 to 103%, the precision ranged from 3.1 to 7.5% (n = 6), and the inter-day precision was from 6.1 to 11.1% (n = 5). Only one of 15 selected real samples tested positive for GSM, and the concentration was 3 ng/L. This method was confirmed to be simple, fast, efficient, and accurate for the determination of earthy-musty compounds in aqueous samples. PMID:27063712

  10. [Simultaneous determination of eight furocoumarines in cosmetics by high performance liquid chromatography and verification by liquid chromatography-tandem mass spectrometry].

    PubMed

    Ma, Huijuan; Ma, Qiang; Li, Wentao; Meng, Xianshuang; Li, Jingrui; Bai, Hua; Jiao, Yang; Zhang, Xiaoli

    2013-05-01

    A method using high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of eight furocoumarines (8-hydroxypsoralen, psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin) in cosmetics. The cosmetic samples, including cream, lotion, shampoo, powder and lipstick, were supersonically extracted with appropriate solvents. The extract was centrifuged, and the supernatant was filtered through a membrane, and then separated on an Agilent Zorbax SB-Phenyl chromatographic column (250 mm x 4.6 mm, 5 microm) by gradient elution at a flow rate of 1.0 mL/min with methanol-acetonitrile-water as mobile phases. The column temperature was set at 30 degrees C. The wavelength of detection was 250 nm. The limits of quantification (LOQs) were 0.25 mg/kg for 8-hydroxypsoralen and 0.5 mg/kg for psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin. The recoveries at three spiked levels were in the range of 85.0% - 105.8% with the relative standard deviations (RSDs) of 0.41% - 7.90%. The intra-day precision (n=6) was less than 1%, and the inter-day precision (n = 6) was less than 2% for the peak areas of the eight furocoumarines in a mixed standard solution. The method is accurate, simple, rapid and suitable for the determination of the eight furocoumarines in various cosmetic samples. PMID:24010339

  11. Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

    PubMed

    Pichini, Simona; Marchei, Emilia; Martello, Simona; Gottardi, Massimo; Pellegrini, Manuela; Svaizer, Fiorenza; Lotti, Andrea; Chiarotti, Marcello; Pacifici, Roberta

    2015-04-01

    We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 μl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 μl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption. PMID:25659366

  12. Investigation of the persistence of nerve agent degradation analytes on surfaces through wipe sampling and detection with ultrahigh performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Willison, Stuart A

    2015-01-20

    The persistence of chemical warfare nerve agent degradation analytes on surfaces is important, from indicating the presence of nerve agent on a surface to guiding environmental restoration of a site after a release. Persistence was investigated for several chemical warfare nerve agent degradation analytes on indoor surfaces and presents an approach for wipe sampling of surfaces, followed by wipe extraction and liquid chromatography-tandem mass spectrometry detection. Commercially available wipe materials were investigated to determine optimal wipe recoveries. Tested surfaces included porous/permeable (vinyl tile, painted drywall, and wood) and largely nonporous/impermeable (laminate, galvanized steel, and glass) surfaces. Wipe extracts were analyzed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). UPLC provides a separation of targeted degradation analytes in addition to being nearly four times faster than high-performance liquid chromatography, allowing for greater throughput after a large-scale contamination incident and subsequent remediation events. Percent recoveries from nonporous/impermeable surfaces were 60-103% for isopropyl methylphosphonate (IMPA), GB degradate; 61-91% for ethyl methylphosphonate (EMPA), VX degradate; and 60-98% for pinacolyl methylphosphonate (PMPA), GD degradate. Recovery efficiencies for methyl phosphonate (MPA), nerve agent degradate, and ethylhydrogen dimethylphosphonate (EHDMAP), GA degradate, were lower, perhaps due to matrix effects. Diisopropyl methylphosphonate, GB impurity, was not recovered from surfaces. The resulting detection limits for wipe extracts were 0.065 ng/cm(2) for IMPA, 0.079 ng/cm(2) for MPA, 0.040 ng/cm(2) for EMPA, 0.078 ng/cm(2) for EHDMAP, and 0.013 ng/cm(2) for PMPA. The data indicate that laboratories may hold wipe samples for up to 30 days prior to analysis. Target analytes were observed to persist on surfaces for at least 6 weeks. PMID:25495198

  13. The ultra-performance liquid chromatography tandem mass spectrometry method for detection and quantification of C4NP in rat plasma and its application to pharmacokinetic studies

    PubMed Central

    You, J.; Wang, L.; Yang, F.; Shang, J.

    2016-01-01

    Introduction Combretastatins, which are excellent anticancer agents, are isolated from Combretum. A sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for the pharmacokinetic study of a combretastatin analog (C4NP) in rats. Methods Sample pretreatment was finished by simple protein precipitation in which methanol was added to plasma containing an internal standard (buspirone hydrochloride). Liquid chromatograph separation was accomplished on a reverse-phase Kinetex XB-C18 column [50×4.6 mm; internal diameter: 2.6 μm (Phenomenex, Torrance, CA, U.S.A.)] with a gradient mobile phase of acetonitrile (0.05% formic acid, volume for volume) and water (0.05% formic acid) at a flow rate of 0.3 mL/min. The analytes were analyzed in the positive ion by electrospray ionization and quantified in the selective reaction monitoring mode. The entire procedure was validated following the U.S. Food and Drug Administration guidelines for bioanalytical methods validation. Results Our study investigated, for the first time, the detection and pharmacokinetic characteristics of C4NP in Sprague–Dawley rat plasma. The pharmacokinetic results suggest that C4NP is predominantly restricted to blood or extracellular fluid and is not extensively distributed to most organ tissues. In addition, C4NP can be cleared by renal filtration and active tubular secretion in Sprague–Dawley rats. Toxicokinetics of C4NP in these rats indicate that no saturation of the metabolic or excretion process occurs for C4NP, and metabolic induction and accumulation of toxic injury from multiple dosing are both absent. Conclusions For 100 μL of analyte, recovery plus high accuracy and reproducibility indicate that our new ultra-performance liquid chromatography tandem mass spectrometry method is a reliable and high-throughput analytical tool for the pharmacokinetic study of C4NP in rats. Those results should be useful for risk assessment. PMID:26966419

  14. Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

  15. Comparative pharmacokinetics of a proliposome formulation of Ginkgo biloba extract and Ginaton in rats by a sensitive ultra performance liquid chromatography-tandem mass spectrometry method.

    PubMed

    Zheng, Bin; Xing, Gaoyang; Bi, Ye; Yan, Guodong; Wang, Jing; Cheng, Yingkun; Liu, Yan; Ashraf, Muhammad Aqeel; Xie, Jing

    2016-01-01

    As a novel oral drug delivery system, proliposome was applied to improve the solubility of active components of Ginkgo biloba extract (GbE). There are currently few reports focusing on the pharmacokinetic characteristics of proliposome of GbE (GbP). A rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of active components of GbP and a commercial tablet product (Ginaton) in rat plasma was developed and successfully validated. The method was applied to the comparative pharmacokinetic evaluation of GbP and Ginaton in rat plasma. The results indicated that GbP has a significant effect on absorption, elimination and bioavailability of flavonoids and terpenoid lactones in comparison with Ginaton. The obtained results would be helpful for evaluating the absorption mechanism in the gastrointestinal tract in pharmacokinetic level and guiding the development of the novel oral drug delivery system. PMID:26858539

  16. Quantitative Determination of Irinotecan and the Metabolite SN-38 by Nanoflow Liquid Chromatography-Tandem Mass Spectrometry in Different Regions of Multicellular Tumor Spheroids

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Hummon, Amanda B.

    2015-04-01

    A new and simple method was developed to evaluate the distribution of therapeutics in three-dimensional multicellular tumor spheroids (MCTS) by combining serial trypsinization and nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). This methodology was validated with quantitative measurements of irinotecan and its bioactive metabolite, SN-38, in distinct spatial regions of HCT 116 MCTS. Irinotecan showed a time-dependent permeability into MCTS with most of the drug accumulating in the core after 24 h of treatment. The amount of SN-38 detected was 30 times lower than that of the parent drug, and was more abundant in the outer rim and intermediate regions of MCTS where proliferating cells were present. This method can be used to investigate novel and established drugs. It enables investigation of drug penetration properties and identification of metabolites with spatial specificity in MCTS. The new approach has great value in facilitating the drug evaluation process.

  17. Quantitative Determination of Irinotecan and the Metabolite SN-38 by Nanoflow Liquid Chromatography-Tandem Mass Spectrometry in Different Regions of Multicellular Tumor Spheroids

    PubMed Central

    Liu, Xin; Hummon, Amanda B.

    2015-01-01

    A new and simple method was developed to evaluate the distribution of therapeutics in three-dimensional multicellular tumor spheroids (MCTS) by combining serial trypsinization and nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). This methodology was validated with quantitative measurements of irinotecan and its bioactive metabolite, SN-38, in distinct spatial regions of HCT 116 MCTS. Irinotecan showed a time-dependent permeability into MCTS with most of the drug accumulating in the core after 24 hours of treatment. The amount of SN-38 detected was 30 times lower than that of the parent drug, and was more abundant in the outer rim and intermediate regions of MCTS where proliferating cells were present. This method can be used to investigate novel and established drugs. It enables investigation of drug penetration properties and identification of metabolites with spatial specificity in MCTS. The new approach has great value in facilitating the drug evaluation process. PMID:25604392

  18. SMART Digest™ compared with pellet digestion for analysis of human immunoglobulin G1 in rat serum by liquid chromatography tandem mass spectrometry.

    PubMed

    Lanshoeft, Christian; Heudi, Olivier; Cianférani, Sarah

    2016-05-15

    The newly developed SMART Digest™ kit was applied for the sample preparation of human immunoglobulin G1 (hIgG1) in rat serum prior to qualitative and quantitative analyses by liquid chromatography tandem mass spectrometry (LC-MS/MS). The sequence coverages obtained for the light and heavy chains of hIgG1A were 50 and 76%, respectively. The calibration curve was linear from 1.00 to 1000 μg/ml for three of four generic peptides. Overall, the SMART Digest™ kit resulted in similar quantitative data (linearity, sensitivity, accuracy, and precision) compared with the pellet digestion protocol. However, the SMART Digest™ required only 2 h of sample preparation with fewer reagents. PMID:26893107

  19. Simultaneous determination of seven bioactive components in Guizhi Fuling capsule by microwave-assisted extraction combined with ultra performance liquid chromatography tandem mass spectrometry.

    PubMed

    Sui, Yang; Zhao, Long-Shan; Wang, Zhen-Zhong; Zhao, Yu-Tong; Xiao, Wei; Xiong, Zhi-Li

    2016-01-01

    A simple, rapid and reliable microwave-assisted extraction (MAE) combined with ultra performance liquid chromatography tandem mass spectrometry method was developed for simultaneous determination of the seven bioactive constituents in Guizhi Fuling capsule (GFC), namely gallic acid, amygdalin, albiflorin, paeoniflorin, paeonol, cinnamic acid and pachymic acid, respectively. The operation of MAE optimised through orthogonal array design experiment was performed at 80°C for 10 min with methanol-water (70:30, v/v) as the extracting solvent. The method was validated including intra- and inter-day precision, repeatability and stability, with relative standard deviation less than 3.9%, 3.3%, 4.4% and 3.1%, respectively. All analytes showed the good linearity (r >0.999), and their average recoveries varied between 98.2% and 101.2%. The results indicated that this method was simple, effective and suitable for the quality control of GFC. PMID:26189716

  20. Validation of a multi-residue liquid chromatography-tandem mass spectrometry confirmatory method for 10 anticoccidials in eggs according to Commission Decision 2002/657/EC.

    PubMed

    Dubreil-Chéneau, Estelle; Bessiral, Mélaine; Roudaut, Brigitte; Verdon, Eric; Sanders, Pascal

    2009-11-13

    A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous detection and confirmation of halofuginone, robenidine, diclazuril, nicarbazin, monensin, narasin, lasalocid, salinomycin, maduramicin and semduramicin in whole egg has been developed and validated. The anticoccidial residues were extracted by acetonitrile, evaporated and dissolved in a sodium acetate/acetonitrile mixture. Then, the samples were injected on a C8 column in a gradient mode. Diclazuril-bis, DNC-d8 and nigericin were used as internal standards. The results of the full validation in accordance with the guidelines of the Commission Decision no 2002/657/EC are presented. This rapid and sensitive method was found suitable to confirm the anticoccidials at 1 and at 75 microg kg(-1) for the MRL compound lasalocid. PMID:19442981

  1. Analysis of soluble lignin in sugarcane by ultrahigh performance liquid chromatography-tandem mass spectrometry with a do-it-yourself oligomer database.

    PubMed

    Kiyota, Eduardo; Mazzafera, Paulo; Sawaya, Alexandra C H F

    2012-08-21

    Lignin is a polymer found in the cell wall of plants and is one of the main obstacles to the implementation of second-generation ethanol production because it confers the recalcitrance of the lignocellulosic material. The recalcitrance of biomass is affected by the amount of lignin, by its monomer composition, and the way the monomers are arranged in the plant cell wall. Analysis of lignin structure demands mass spectrometry analysis, and identification of oligomers is usually based on libraries produced by laborious protocols. A robust method to build a do-it-yourself lignin oligomer library was tested. This library can be built using commercially available enzymes, standards, and reagents and is relatively easy to accomplish. An ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the separation and characterization of monomers and oligomers was developed and was equally applicable to the synthetic lignin and to soluble lignin extracted from a sample of sugar cane. PMID:22830944

  2. Detection and quantitation of benzo(a)pyrene-derived DNA adducts in mouse liver by liquid chromatography - tandem mass spectrometry: comparison with P-32-postlabeling

    SciTech Connect

    Singh, R.; Gaskell, M.; Le Pla, R.C.; Kaur, B.; Azim-Araghi, A.; Roach, J.; Koukouves, G.; Souliotis, V.L.; Kyrtopoulos, S.A.; Farmer, P.B.

    2006-06-19

    The polycyclic aromatic hydrocarbon, benzo(a)pyrene (B(a)P) is a proven animal carcinogen that is potentially carcinogenic to humans. B( a)P is an ubiquitous environmental pollutant and is also present in tobacco smoke, coal tar, automobile exhaust emissions, and charred food. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using electrospray ionization and selected reaction monitoring (SRM) has been developed for the detection of 10-(deoxyguanosin-N{sub 2}-yl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo(a)pyrene (B(a)PDE-N{sub 2}dG) adducts formed in DNA following the metabolic activation of B(a)P to benzo(a) pyrene-7,8-dihydrodiol-9,10-epoxide (B(a)PDE).

  3. Diagnostic application of the exponentially modified Gaussian model for peak quality and quantitation in high-throughput liquid chromatography-tandem mass spectrometry.

    PubMed

    Zabell, Adam P R; Foxworthy, Tyler; Eaton, Kimberly Napoli; Julian, Randall K

    2014-11-21

    Typical area calculation for a chromatographic peak assumes the observed signal strength at every measurement is an exactly accurate count of the signal. We compared that approach to one using the exponentially modified Gaussian (EMG) in an automated, clinical production setting. Peak areas in a 47 analyte high throughput clinical production liquid chromatography-tandem mass spectrometry assay were compared across four months of production data to determine trends over the lifespan of a chromatographic column. The EMG parameters were superior to traditional quality control methods for monitoring data reproducibility, accuracy and precision. Because the EMG calculations are performed for every peak in the system, a constant monitor of system health is integrated into the operational workflow. Parameter trends confirmed the need for column replacement, and indicated the opportunity for a reduced schedule of preventive and routine maintenance. PMID:25441075

  4. Micro-solid phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry for the determination of stimulants, hallucinogens, ketamine and phencyclidine in oral fluids.

    PubMed

    Sergi, Manuel; Compagnone, Dario; Curini, Roberta; D'Ascenzo, Giuseppe; Del Carlo, Michele; Napoletano, Sabino; Risoluti, Roberta

    2010-08-24

    A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography-tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL(-1) for cocaine and 4.9 ng mL(-1) for psilocybine, with coefficients of determination (r(2)) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences. PMID:20800724

  5. Determination of quinolone residues in infant and young children powdered milk combining solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Herrera-Herrera, Antonio V; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel A; Herrero, Miguel; Cifuentes, Alejandro

    2011-10-21

    The present work describes a method based on solid-phase extraction (SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of three quinolones (pipemidic acid, oxolinic acid and flumequine) and twelve fluoroquinolones (marbofloxacin, fleroxacin, pefloxacin, levofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin, lomefloxacin, difloxacin, sarafloxacin, and moxifloxacin) in different infant and young children powdered milks. After suitable deproteination of the reconstituted powdered samples, a SPE procedure was developed providing recovery values higher than 84% (RSDs lower than 13%) for all the analytes, with limits of detection between 0.04 and 0.52 μg/kg. UPLC-MS/MS analyses were carried out in less than 10 min. Sixteen infant and young children powdered milk samples of different origin, type and composition bought at Spanish markets were analyzed. Residues of the selected antibiotics were not detected in any of the analyzed samples. PMID:21683365

  6. Alkaloid profiling of the traditional Chinese medicine Rhizoma corydalis using high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry

    PubMed Central

    Sun, Mingqian; Liu, Jianxun; Lin, Chengren; Miao, Lan; Lin, Li

    2014-01-01

    Since alkaloids are the major active constituents of Rhizoma corydalis (RC), a convenient and accurate analytical method is needed for their identification and characterization. Here we report a method to profile the alkaloids in RC based on liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (LC–Q-TOF-MS/MS). A total of 16 alkaloids belonging to four different classes were identified by comparison with authentic standards. The fragmentation pathway of each class of alkaloid was clarified and their differences were elucidated. Furthermore, based on an analysis of fragmentation pathways and alkaloid profiling, a rapid and accurate method for the identification of unknown alkaloids in RC is proposed. The method could also be useful for the quality control of RC. PMID:26579385

  7. Improved liquid chromatography-tandem mass spectrometric method for the determination of ethyl glucuronide concentrations in hair: applications to forensic cases.

    PubMed

    Imbert, Laurent; Gaulier, Jean-Michel; Dulaurent, Sylvain; Morichon, Julien; Bevalot, Fabien; Izac, Paul; Lachâtre, Gérard

    2014-01-01

    Ethyl glucuronide (EtG) is a direct marker of ethanol consumption, and its assay in hair is an efficient tool for chronic alcoholism diagnosis. In 2012, the Society of Hair Testing proposed a new consensus for hair concentrations interpretation, strongly advising the use of analytical methods providing a limit of quantification of less than 3 pg/mg. The present work describes the optimization and validation of a previously developed liquid chromatography-tandem mass spectrometric method in order to comply with this recommendation. The concentration range of this improved method is from 3 to 1,000 pg/mg. Some cases are then described to illustrate the usefulness of hair EtG: a forensic post-mortem case and two cases of suspension of driving licences. Finally, hair samples of some teetotallers (n = 10) have been analyzed, which allowed neither to quantitate nor to detect any trace of EtG. PMID:23824336

  8. Performance characterization of a quantitative liquid chromatography-tandem mass spectrometric method for 12 macrolide and lincosamide antibiotics in salmon, shrimp and tilapia.

    PubMed

    Dickson, Leslie C

    2014-09-15

    This paper describes an extension and performance characterization of a quantitative confirmatory multi-residue liquid chromatography-tandem mass spectrometric method for residues of macrolide and lincosamide antibiotics, originally validated for application to bovine kidney tissues, to tissues of salmon, shrimp and tilapia. The 12 analytes include clindamycin, erythromycin A, gamithromycin, josamycin, lincomycin, neospiramycin 1, oleandomycin, pirlimycin, spiramycin 1, tildipirosin, tilmicosin and tylosin A. The limit of detection was 0.5 μg/kg. Within-laboratory precision evaluated over the analytical range of 5.0-50.0 μg/kg ranged from 4 to 17%. The accuracy of the method ranged from 80 to 112%. Recoveries ranged from 47 to 99% with all but one recovery above 60%. This is the first report of a quantitative confirmatory method for gamithromycin, pirlimycin and tildipirosin in fish and shrimp. PMID:25125397

  9. [Determination of amantadine and rimantadine residues in egg and chicken samples by dispersive solid phase extraction purification-ultra high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Lin, Tao; Fan, Jianlin; Liu, Xingyong; Chen, Xinglian; Li, Yangang; Liu, Hongcheng

    2015-11-01

    A method was developed for the determination of residual amantadine and rimantadine in eggs and chickens by dispersive solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry. Egg and chicken samples were extracted with ammonia water-acetonitrile (2:98, v/v). The extraction solution was dried to 1 mL under nitrogen, and then purified by dispersive solid phase extraction method with C18 and NH2 sorbents. After purification, the extraction solution was filtered through a filter. The target compounds were analyzed by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) on a ZORBAX C18 column using a mixture of 1 mmol/L ammonium acetate solution (containing 0.1% (v/v) formic acid) and methanol as mobile phases with gradient elution. The mass spectrometer was operated under multiple reaction monitoring (MRM) mode in positive mode. The good linearities were obtained for amantadine and rimantadine at a concentration range of 0.15-10.0 μg/L. The limits of detection for amantadine and rimantadine were all 0.05 μg/kg, and the limits of quantification were 0.20 μg/kg. The recoveries of amantadine and rimantadine in eggs and chickens at three spiked levels (0.2, 1.0 and 2.0 μg/kg) age of 89%-108% with the relative standard deviations of 5.0%-8.6%. The results demonstrated that the method is suitable for the determination of amantadine and rimantadine in eggs and chickens. PMID:26939363

  10. Chemometric approach to open validation protocols: Prediction of validation parameters in multi-residue ultra-high performance liquid chromatography-tandem mass spectrometry methods.

    PubMed

    Alladio, Eugenio; Pirro, Valentina; Salomone, Alberto; Vincenti, Marco; Leardi, Riccardo

    2015-06-01

    The recent technological advancements of liquid chromatography-tandem mass spectrometry allow the simultaneous determination of tens, or even hundreds, of target analytes. In such cases, the traditional approach to quantitative method validation presents three major drawbacks: (i) it is extremely laborious, repetitive and rigid; (ii) it does not allow to introduce new target analytes without starting the validation from its very beginning and (iii) it is performed on spiked blank matrices, whose very nature is significantly modified by the addition of a large number of spiking substances, especially at high concentration. In the present study, several predictive chemometric models were developed from closed sets of analytes in order to estimate validation parameters on molecules of the same class, but not included in the original training set. Retention time, matrix effect, recovery, detection and quantification limits were predicted with partial least squares regression method. In particular, iterative stepwise elimination, iterative predictors weighting and genetic algorithms approaches were utilized and compared to achieve effective variables selection. These procedures were applied to data reported in our previously validated ultra-high performance liquid chromatography-tandem mass spectrometry multi-residue method for the determination of pharmaceutical and illicit drugs in oral fluid samples in accordance with national and international guidelines. Then, the partial least squares model was successfully tested on naloxone and lormetazepam, in order to introduce these new compounds in the oral fluid validated method, which adopts reverse-phase chromatography. Retention time, matrix effect, recovery, limit of detection and limit of quantification parameters for naloxone and lormetazepam were predicted by the model and then positively compared with their corresponding experimental values. The whole study represents a proof-of-concept of chemometrics potential to

  11. Determination of caramel colorants' by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

    PubMed

    Goscinny, Séverine; Hanot, Vincent; Trabelsi, Hasna; Van Loco, Joris

    2014-01-01

    2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml⁻¹ (LOQ) to 500 ng ml⁻¹ with recoveries of 75.4-112.4% and RSDs of 1.5-15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25-30 µg ml⁻¹ with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml⁻¹. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml⁻¹). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml⁻¹), which required a high level of dilution before following the standard addition protocol. PMID:25060737

  12. Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    SciTech Connect

    Owens, J; Hok, S; Alcaraz, A; Koester, C

    2008-11-13

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  13. Planar graphene oxide-based magnetic ionic liquid nanomaterial for extraction of chlorophenols from environmental water samples coupled with liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Mei-Qiang; Su, Jie; Hu, Jian-Qiang; Wang, Qian; Dong, Chun-Ying; Pan, Sheng-Dong; Jin, Mi-Cong

    2016-08-12

    A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water. PMID:27425762

  14. Determination of capsaicin, dihydrocapsaicin, and nonivamide in self-defense weapons by liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry.

    PubMed

    Reilly, C A; Crouc, D J; Yost, G S; Fatah, A A

    2001-04-01

    Sensitive and selective liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) methods for the analysis of capsaicin, dihydrocapsaicin, and nonivamide in pepper spray products have been developed. Chromatographic separation of the capsaicinoid analogues was achieved using a reversed-phase HPLC column and a stepwise gradient of methanol and distilled water containing 0.1% (v/v) formic acid. Identification and quantification of the capsaicinoids was achieved by electrospray ionization single-stage mass spectrometry monitoring the protonated molecules of the internal standard (m/z 280), capsaicin (m/z 306), dihydrocapsaicin (m/z 308), and nonivamide (m/z 294) or by tandem mass spectrometry monitoring the appropriate precursor-to-product-ion transitions. The plot of concentration versus peak area ratio was linear over the range of 10-750 ng/ml using LC-MS and 10-500 ng/ml using LC-MS-MS. However, to accurately quantify the capsaicinoids in the pepper spray products calibration curves between 10 and 1000 ng were constructed and fit using a weighted quadratic equation. Using the quadratic curve, the accuracy of the assay ranged from 91 to 102% for all analytes. The intra-assay precision (RSD) for capsaicin was 2% at 25 ng/ml, 10% at 500 ng/ml, and 3% at 800 ng/ml. The inter-assay precision (RSD) for capsaicin was 6% at 25 ng/ml, 6% at 500 ng/ml, and 9% at 800 ng/ml. Similar values for inter- and intra-assay precision were experimentally obtained for both dihydrocapsaicin and nonivamide. The analysis of selected pepper spray products demonstrated that the capsaicinoid concentration in the products ranged from 0.7 to 40.5 microg/microl. PMID:11330795

  15. [Determination of dimethyl yellow and diethyl yellow in yuba and dried beancurd by modified QuEChERS method and liquid chromatography-tandem mass spectrometry].

    PubMed

    Fan, Sufang; Li, Qiang; Ma, Junmei; Li, Hui; Zhang, Yan

    2015-06-01

    A modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method followed by liquid chromatography-tandem mass spectrometric analysis was developed for the determination of dimethyl yellow and diethyl yellow in yuba and dried beancurd. Yuba and dried beancurd samples were soaked by deionized water, then acetonitrile was added to extract the analytes. Sodium chloride and anhydrous magnesium sulfate were added for liquid-liquid separation. The extracts were cleaned-up by dispersive solid-phase using N-propyl diethylamine. The analytes were separated by liquid chromatography and determined by mass spectrometry. External standard method was used for quantification. The recoveries of dimethyl yellow were in the range of 73.5%-84.5% at spiked levels of 0.3, 1 and 10 kg/kg and the recoveries of diethyl yellow were in range of 70.5%-81.2% at spiked levels of 0.1,1 and 10 µg/kg; relative standard deviations of the method were lower than 11%. The limit of detection and the limit of quantification of dimethyl yellow were 0.1 µg/kg and 0.3 µg/kg, respectively; the limit of detection and the limit of quantification of diethyl yellow were 0.05 µg/kg and 0.1 µg/kg, respectively. This method can be used in rapid screening and quantitative analysis of dimethyl yellow and diethyl yellow in yuba and dried beancurd. PMID:26536771

  16. Determination of perfluorocompounds in popcorn packaging by pressurised liquid extraction and ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Martínez-Moral, María Pilar; Tena, María Teresa

    2012-11-15

    The development and characterisation of a method based on reverse-phase ultra-performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) with negative electrospray ionisation (ESI) to determine perfluorinated compounds (PFCs) in packaging is presented in this paper. Analytes were quantitatively recovered from packaging with methanol in only one PLE cycle of 6 min at 100 °C. The UPLC allowed the successful separation of the studied PFCs in less than 4 min. The whole method presented good precision, with RSDs below 8%, LODs from 0.6 to 16 ng g(-1); and excellent recovery values, around 100% in all cases, were achieved. The PLE-UPLC-MS method was applied to the analysis of popcorn packaging for microwave cooking. Besides the most commonly studied PFCs: PFOA and PFOS, the presence of other perfluorocarboxylic acids (PFCAs) in popcorn packaging is evidenced in this work. PMID:23158298

  17. Determination of Tenacissoside A in rat plasma by liquid chromatography-tandem mass spectrometry method and its application to pharmacokinetic study.

    PubMed

    Zhao, Luhua; Xiang, Bingren; Chen, Jing; Tan, Xiying; Wang, Dawei; Chen, Daofeng

    2009-07-01

    A sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the first time for the estimation of Tenacissoside A in the rats' plasma, which is the major active constituent in Marsdenia tenacissima. Tenacissoside A was extracted from the rats' plasma by using liquid-liquid extraction (LLE), medroxyprogesterone acetate was used as the internal standard. An Alltech C18 column (250 mm x 4.6mm, 5 microm) was used to provide chromatographic separation by detection with mass spectrometry operating in selected ion monitoring (SIM) mode. The method was validated over the concentration range of 1-250 ng/mL for Tenacissoside A. The precisions within and between-batch (CV%) were both less than 15% and accuracy ranged from 90 to 102%. The lower limit of quantification was 1 ng/mL and extraction recovery was 88.3% on average. The validated method was used to study the pharmacokinetic profile of Tenacissoside A in rat after administration. PMID:19481986

  18. A selective biomarker for confirming nitrofurazone residues in crab and shrimp using ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Shuai; Guo, Yuanming; Yan, Zhongyong; Sun, Xiumei; Zhang, Xiaojun

    2015-12-01

    Reliably detecting nitrofurazone (NFZ) residues in farmed crab and shrimp was previously hindered by lack of appropriately specific analytical methodology. Parent NFZ rapidly breaks down in meat, and the commonly used side-chain metabolite, semicarbazide (SEM), is non-specific as it occurs naturally in crustacean shell often leading to 'false positive' detections in meat. Using 5-nitro-2-furaldehyde (NF) as marker metabolite, following pre-column derivatization with 2,4-dinitrophenylhydrazine (DNPH), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis in negative electrospray ionization mode enabled confirmation of NFZ residues in deliberately treated whole crab, crab meat and shrimp meat, with a limit of detection (LOD) and limit of quantification (LOQ) below 1 ng g(-1). Meanwhile, the derivatives of DNPH-NF were synthesized for the first time, purified by preparative liquid chromatography and structure characterized with nuclear magnetic resonance spectroscopy ((1)H-NMR). The purity of derivative was checked by ultra-performance liquid chromatography-tunable ultraviolet (UPLC-TUV), and the contents were beyond 99.9%. For comparison purposes, crustacean samples were analysed using both NF and SEM marker metabolites. NFZ treatment was revealed by both NF and SEM marker metabolites, but untreated crab also showed measurable levels of SEM which could potentially be misinterpreted as evidence of illegal NFZ use. PMID:26427505

  19. Detection of Stimulants and Narcotics by Liquid Chromatography-Tandem Mass Spectrometry and Gas Chromatography-Mass Spectrometry for Sports Doping Control.

    PubMed

    Ahrens, Brian D; Kucherova, Yulia; Butch, Anthony W

    2016-01-01

    Sports drug testing laboratories are required to detect several classes of compounds that are prohibited at all times, which include anabolic agents, peptide hormones, growth factors, beta-2 agonists, hormones and metabolic modulators, and diuretics/masking agents. Other classes of compounds such as stimulants, narcotics, cannabinoids, and glucocorticoids are also prohibited, but only when an athlete is in competition. A single class of compounds can contain a large number of prohibited substances and all of the compounds should be detected by the testing procedure. Since there are almost 70 stimulants on the prohibited list it can be a challenge to develop a single screening method that will optimally detect all the compounds. We describe a combined liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) testing method for detection of all the stimulants and narcotics on the World Anti-Doping Agency prohibited list. Urine for LC-MS/MS testing does not require sample pretreatment and is a direct dilute and shoot method. Urine samples for the GC-MS method require a liquid-liquid extraction followed by derivatization with trifluoroacetic anhydride. PMID:26660193

  20. Determination of gymnemagenin in rat plasma using high-performance liquid chromatography-tandem mass spectrometry: application to pharmacokinetics after oral administration of Gymnema sylvestre extract.

    PubMed

    Kamble, Bhagyashree; Gupta, Ankur; Patil, Dada; Khatal, Laxman; Janrao, Shirish; Moothedath, Ismail; Duraiswamy, Basavan

    2013-05-01

    A sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and validated for the determination of gymnemagenin (GMG), a triterpene sapogenin from Gymnema sylvestre, in rat plasma using withaferin A as the internal standard (IS). Plasma samples were simply extracted using liquid-liquid extraction with tetra-butyl methyl ether. Chromatographic separation was performed on Luna C(18) column using gradient elution of water and methanol (with 0.1% formic acid and 0.3% ammonia) at a flow rate of 0.8 mL/min. GMG and IS were eluted at 4.64 and 4.36 min, ionized in negative and positive mode, respectively, and quantitatively estimated using multiple reaction monitoring (MRM) mode. Two MRM transitions were selected at m/z 505.70 → 455.5 and m/z 471.50 → 281.3 for GMG and IS, respectively. The assay was linear over the concentration range of 5.280-300.920 ng/mL. The mean plasma extraction recoveries for GMG and IS were found to be 80.92 ± 8.70 and 55.63 ± 0.76%, respectively. The method was successfully applied for the determination of pharmacokinetic parameters of GMG after oral administration of G. sylvestre extract. PMID:23225496

  1. A highly sensitive method for the determination of 7-aminonitrazepam, a metabolite of nitrazepam, in human urine using high-performance electrospray liquid chromatography tandem mass spectrometry.

    PubMed

    Kuang, Hua; Li, Qiusheng; Shen, Chongyu; Xu, Jinzhong; Yuan, Yuan; Xu, Chuanlai; Wang, Wuyang

    2009-07-01

    A highly sensitive method has been developed for the determination of urinary 7-aminonitrazepam (7-ANZP), the major metabolite of nitrazepam, using high-performance electrospray liquid chromatography tandem mass spectrometry. The samples were prepared for analysis by adding 7-aminoclonazepam (7-ACZP, internal standard), hydrolysis with beta-glucuronidase and liquid-liquid extraction. Mass spectral acquisition was achieved by selectively monitoring the reaction between the two diagnostic transition reactions. Qualitative analysis was based on the retention time, and the quantitation was carried out by comparison with the internal standard. The recoveries of different concentrations of 7-ANZP from spiked blank samples was 89.0-95.2%, and the relative standard deviation was below 6.4%. The limit of determination in urine was 0.07 ng/mL, and the limit of quantitation was 0.5 ng/mL in the linear range of 1-50 ng/mL. This method possesses the merits of convenient operation, high sensitivity and good repeatability, making it a practical method for analysis of 7-ANZP in urine. PMID:19319833

  2. Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma.

    PubMed

    Rood, Johannes J M; van Bussel, Mark T J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2016-09-15

    A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was performed in a range from 1 to 1000ng/ml, with the lowest level corresponding to the lower limit of quantitation. Gradient elution was performed on a 1.8μm particle trifunctional bonded C18 column by 1% (v/v) formic acid in water, and acetonitrile as mobile phase. The analyte was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer after positive ionization with the heated electrospray interface. Within-day precisions ranged from 3.4 to 10.3%, and between-day precisions from 3.8 to 10.4%, accuracies were 95.5-102.8%. Plasma (either lithium heparin or sodium EDTA) pretreatment was performed by salting-out assisted liquid-liquid extraction using acetonitrile and magnesium sulfate. This method was used to analyze the osimertinib blood plasma levels of five adult patients with metastatic T790M mutated non-small cellular lung carcinoma for therapeutic drug monitoring purposes. PMID:27469903

  3. Multiresidue Determination of β2-Agonists Including Phenylethanolamine A in Animal-Derived Food by Ultra-High Performance Liquid Chromatography/Tandem Mass Spectrometry.

    PubMed

    Wang, Lian; Pu, Rong-chun; Wang, Xi-xi; Luo, Chun-ying; Zhang, Li-chun; Zhang, Xin-shen

    2015-07-01

    A comprehensive ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) procedure for detection of nine β-agonists in animal-derived food is described. The method was based on enzymatic hydrolysis with β-glucuronidase from Helix pomatia, followed by a liquid-liquid extraction procedure with perchloric acid and a solid-phase extraction scheme using two kinds of cartridges, HLB and MCX. The influence of sample solution pH in the extraction recovery was studied, and pH 4.0 was found to give the best recovery. The analytes were eluted with methanol containing 4% ammonia. A validation procedure for quantitative analysis of β-agonists in animal-derived food was performed. The three kinds of internal standards, d3-salbutamol, d6-ractopamine and d9-clenpenterol, were applied in the sample preparation and detection of UHPLC/MS/MS. The recoveries from spiked samples ranged between 74.9 and 106.9%. The relative standard deviations of detection were at 0.7-9.6%. The limits of detection and quantification were 0.01-0.05 and 0.03-0.20 µg/kg, respectively. The effect of sample matrix in the detection was discussed in detail. PMID:25480455

  4. Development of a rapid, multi-class method for the confirmatory analysis of anti-inflammatory drugs in bovine milk using liquid chromatography tandem mass spectrometry.

    PubMed

    Malone, E M; Dowling, G; Elliott, C T; Kennedy, D G; Regan, L

    2009-11-13

    A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous identification, confirmation and quantitation of seven licensed anti-inflammatory drugs (AIDs) in bovine milk. The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC. Two classes of AIDs were investigated, corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs). The developed method is capable of detecting and confirming dexamethasone (DXM), betamethasone (BTM), prednisolone (PRED), tolfenamic acid (TLF), 5-hydroxy flunixin (5-OH-FLU), meloxicam (MLX) and 4-methyl amino antipyrine (4-MAA) at their associated maximum residue limits (MRLs). These compounds represent all the corticosteroids and NSAIDs licensed for use in bovine animals producing milk for human consumption. These compounds have never been analysed before in the same method and also 4-methyl amino antipyrine has never been analysed with the other licensed NSAIDs. The method can be considered rapid as permits the analysis of up to 30 samples in one day. Milk samples are extracted with acetonitrile; sodium chloride is added to aid partition of the milk and acetonitrile mixture. The acetonitrile extract is then subjected to liquid-liquid purification by the addition of hexane. The purified extract is finally evaporated to dryness and reconstituted in a water/acetonitrile mixture and determination is carried out by LC-MS/MS. Decision limit (CCalpha) values and detection capability (CCbeta) values have been established for each compound. PMID:19467664

  5. Simultaneous determination of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk by ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Yuanyuan; Li, Xiaowei; Zhang, Zhiwen; Ding, Shuangyang; Jiang, Haiyang; Li, Jiancheng; Shen, Jianzhong; Xia, Xi

    2016-02-01

    A sensitive, confirmatory ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated to detect 23 veterinary drugs and metabolites (nitroimidazoles, benzimidazoles, and chloramphenicol components) in bovine milk. Compounds of interest were sequentially extracted from milk with acetonitrile and basified acetonitrile using sodium chloride to induce liquid-liquid partition. The extract was purified on a mixed mode solid-phase extraction cartridge. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged analytes in a 9 min chromatography run time. Recoveries based on matrix-matched calibrations and isotope labeled internal standards for milk ranged from 51.7% to 101.8%. The detection limits and quantitation limits of the analytical method were found to be within the range of 2-20 ng/kg and 5-50 ng/kg, respectively. The recommended method is simple, specific, and reliable for the routine monitoring of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk samples. PMID:26304348

  6. Validation of a new liquid chromatography- tandem mass spectrometry ion-trap technique for the simultaneous determination of thirteen anticoagulant rodenticides, drugs, or natural products.

    PubMed

    Fourel, Isabelle; Hugnet, Christophe; Goy-Thollot, Isabelle; Berny, Philippe

    2010-03-01

    The purpose of this study was to develop and validate a liquid chromatography-tandem mass spectrometry method for the identification and quantification of anticoagulant (anti-vitamin K or AVK) compounds, including rodenticides, drugs, and natural products because no published method could be found. The proposed method is based on ion-trap technology with electrospray ionization (ESI) and multiple reaction monitoring (MRM) technique. Each AVK is identified by means of its retention time, precursor ion, and two product ions. Plasma samples are extracted by liquid-liquid partition on Toxi-tube B((R)). The method was validated on dog plasma and gave good results in terms of specificity, linearity, and percent recovery for the 14 AVK tested (warfarin, acenocoumarol, bromadiolone, brodifacoum, chlorophacinone, coumatetralyl, dicoumarol, difenacoum, difethialone, flocoumafen, fluindione, phenindione, and tioclomarol). The limits of detection ranged from 5 to 25 ng/mL. Intraday repeatability was good, but interday repeatability was more variable though still sufficient for our diagnostic purposes. The technique was successfully applied in a series of clinical investigations to demonstrate its applicability in various animal species and gave very high sensitivity and specificity results. PMID:20223102

  7. Quantification of Oxidized and Unsaturated Bile Alcohols in Sea Lamprey Tissues by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Li, Ke; Scott, Anne M; Chung-Davidson, Yu-Wen; Bussy, Ugo; Patel, Trinkal; Middleton, Zoe E; Li, Weiming

    2016-01-01

    A sensitive and reliable method was developed and validated for the determination of unsaturated bile alcohols in sea lamprey tissues using liquid-liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The liver, kidney, and intestine samples were extracted with acetonitrile and defatted by n-hexane. Gradient UHPLC separation was performed using an Acquity BEH C18 column with a mobile phase of water and methanol containing 20 mM triethylamine. Multiple reaction monitoring modes of precursor-product ion transitions for each analyte was used. This method displayed good linearity, with correlation coefficients greater than 0.99, and was validated. Precision and accuracy (RSD %) were in the range of 0.31%-5.28%, while mean recoveries were between 84.3%-96.3%. With this technique, sea lamprey tissue samples were analyzed for unsaturated bile alcohol analytes. This method is practical and particularly suitable for widespread putative pheromone residue analysis. PMID:27563866

  8. Determination of tulobuterol in rat plasma using a liquid chromatography-tandem mass spectrometry method and its application to a pharmacokinetic study of tulobuterol patch.

    PubMed

    Han, Xiao; Liu, Ran; Ji, Lifang; Hui, Mei; Li, Qing; Fang, Liang; Bi, Kaishun

    2016-01-01

    A sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for determination of tulobuterol in rat plasma for the first time. Plasma samples were extracted by liquid-liquid extraction method with methyl tert-butyl ether and the analyte and clenbuterol (IS) were separated on a Venusil MP C18 column (100mm×2.1mm, 3μm) using 0.1% formic acid-water-methanol as mobile phase, with a runtime of 5min. The analyte was detected in multiple reaction monitoring (MRM) mode with positive electrospray ionization. Transitions of m/z 228.2→154.0 for tulobuterol and m/z 277.1→203.0 for the clenbuterol were monitored. The linear range was 0.5-100ng/ml (r=0.9967) for tulobuterol with the lower limit of quantitation of 0.5ng/ml. The intra-day and inter-day precisions were less than 10.3% for the analyte and the accuracy was less than -8.6%. The RSD of matrix effect and recovery yield were within ±15% of nominal concentrations and tulobuterol was stable during stability studies. The validated method has been successfully applied to a pharmacokinetic study of three doses of tulobuterol patch in rats for the first time. PMID:26638035

  9. Determination of landiolol, an ultra-short-acting β₁-receptor antagonist, in human plasma by liquid chromatography-tandem mass spectrometry.

    PubMed

    He, Qun; Shi, Meiyun; Liu, Xidong; Sun, Yantong; Hu, Lianghai; Yang, Yan; Fawcett, J Paul; Gu, Jingkai; Zhao, Limei

    2012-04-01

    A method for the determination of landiolol, an ultra-short-acting β₁-adrenoreceptor antagonist, in human plasma has been developed and validated. With the addition of pyridostigmine bromide to stabilize landiolol in the blood/plasma samples, and bisoprolol as internal standard, plasma samples were subjected to liquid-liquid extraction with diethyl ether:dicholoromethane (60:40, v/v) prior to assay by liquid chromatography-tandem mass spectrometry. Separation was performed on a TC-C₁₈ column (150 mm × 4.6 mm, 5 μm) using a mobile phase of methanol:10 mM ammonium acetate containing 1% formic acid (65:35, v/v) in a run time of 3.5 min. Detection involved electrospray ionization in the positive ion mode followed by multiple reaction monitoring of the precursor-to-product ion transitions of landiolol at m/z 510.1→157.2 and bisoprolol at m/z 326.3→116.1. The method was linear over the concentration range 0.5-500 ng/ml with a lower limit of quantitation of 0.5 ng/ml. Intra- and inter-day precisions (as relative standard deviation, RSD) were <4.4% and <10.0%, respectively, with accuracy (as relative error, RE) <10.0%. The method was successfully applied to a clinical pharmacokinetic study involving a continuous infusion of landiolol hydrochloride to healthy Chinese volunteers. PMID:22418070

  10. Simultaneous and rapid determination of gefitinib, erlotinib and afatinib plasma levels using liquid chromatography/tandem mass spectrometry in patients with non-small-cell lung cancer.

    PubMed

    Hayashi, Hideki; Kita, Yutaro; Iihara, Hirotoshi; Yanase, Koumei; Ohno, Yasushi; Hirose, Chiemi; Yamada, Maya; Todoroki, Kenichiro; Kitaichi, Kiyoyuki; Minatoguchi, Shinya; Itoh, Yoshinori; Sugiyama, Tadashi

    2016-07-01

    A simultaneous, selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of gefitinib, erlotinib and afatinib in 250 μL samples of human blood plasma. Diluted plasma samples were extracted using a liquid-phase extraction procedure with tert-butyl methyl ether. The three drugs were separated by high-performance liquid chromatography using a C18 column and an isocratic mobile phase running at a flow rate of 0.2 mL/min for 5 min. The drugs were detected using a tandem mass spectrometer with electrospray ionization using imatinib as an internal standard. Calibration curves were generated over the linear concentration range of 0.05-100 nm in plasma with a lower limit of quantification of 0.01 or 0.05 nm for all compounds. Finally, the validated method was applied to a clinical pharmacokinetic study in patients with nonsmall-cell lung cancer (NSCLC) following the oral administration of afatinib. These results indicate that this method is suitable for assessing the risks and benefits of chemotherapy in patients with NSCLC and is useful for therapeutic drug monitoring for NSCLC treatment. As far as we know, this is the first report on LC-MS/MS method for the simultaneous quantification of NSCLC tyrosine kinase inhibitor plasma concentrations including afatinib. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26525154

  11. Simultaneous determination of four secoiridoid and iridoid glycosides in rat plasma by ultra performance liquid chromatography-tandem mass spectrometry and its application to a comparative pharmacokinetic study.

    PubMed

    Wu, Yun; Ai, Yu; Wang, Fenrong; Ma, Wen; Bian, Qiaoxia; Lee, David Y-W; Dai, Ronghua

    2016-02-01

    A simple, reliable and rapid ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of four secoiridoid (gentiopicroside, swertiamarin, sweroside) and iridoid glycosides (loganic acid), the bio-active ingredients in rat plasma. After liquid-liquid extraction, chromatographic separation was accomplished on a Shim-pack XR-ODS column with a mobile phase consisting of methanol and 0.1% formic acid in water. A triple quadrupole tandem mass spectrometry equipped with an electrospray ionization source was used as detector operating both in positive and negative ionization mode and operated by multiple-reaction monitoring scanning. The lower limits of quantitation were 0.25-30 ng/mL for all the analytes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard (amygdalin) from rat plasma were all >71.4%. The validated method was successfully applied to a comparative pharmacokinetic study of four analytes in rat plasma between normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan and Gentiana macrophylla extract, respectively. Results showed significant differences in pharmacokinetic properties of the analytes among the different groups. PMID:26014753

  12. Simultaneous determination of metoprolol succinate and amlodipine besylate in human plasma by liquid chromatography-tandem mass spectrometry method and its application in bioequivalence study.

    PubMed

    Sarkar, Amlan Kanti; Ghosh, Debotri; Das, Ayan; Selvan, P Senthamil; Gowda, K Veeran; Mandal, Uttam; Bose, Anirbandeep; Agarwal, Sangeeta; Bhaumik, Uttam; Pal, Tapan Kumar

    2008-09-15

    A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol succinate (MPS) and amlodipine besylate (AM) using hydrochlorothiazide (HCTZ) as IS in human plasma. Both the drugs were extracted by simple liquid-liquid extraction with chloroform. The chromatographic separation was performed on a reversed-phase peerless basic C18 column with a mobile phase of methanol-water containing 0.5% formic acid (8:2, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 1-100 ng/ml for MPS and 1-15 ng/ml AM in human plasma. The MRM transition of m/z 268.10-103.10, m/z 409.10-334.20 and m/z 296.00-205.10 were used to measure MPS, AM and HCTZ (IS), respectively. This method was successfully applied to the pharmacokinetic study of fixed dose combination (FDC) of MPS and AM formulation product after an oral administration to Indian healthy human volunteers. PMID:18760977

  13. Determination of chrysotoxine in rat plasma by liquid chromatography-tandem mass spectrometry and its application to a rat pharmacokinetic study.

    PubMed

    Fan, Jingjing; Guan, Li; Kou, Zeqi; Feng, Feng; Zhang, Yanbo; Liu, Wenyuan

    2014-09-15

    Chrysotoxine (CTX), a naturally occurring bibenzyl compound isolated from Dendrobium species, has been reported to have neuroprotective effects. To evaluate its pharmacokinetics in rats, a rapid, sensitive and specific high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method has been developed and validated for the quantification of CTX in rat plasma. Samples were pretreated using a simple liquid-liquid extraction with ethyl acetate and the chromatographic separation was performed on a C18 column with acetonitrile-water (90:10, v/v) as the mobile phase. CTX and the internal standard (wogonin) were detected using a tandem mass spectrometer in positive multiple reaction monitoring mode. Method validation revealed excellent linearity over the range 0.5-1000 ng/mL together with satisfactory intra- and inter-day precision, accuracy and recovery. Stability testing showed that CTX spiked into rat plasma was stable for 8 h at room temperature, for up to two weeks at -20 °C, and during three freeze-thaw cycles. Extracted samples were also observed to be stable over 24 h in an auto-sampler. The method was successfully used to investigate the pharmacokinetic profile of CTX after oral (100 mg/kg) and intravenous (25 mg/kg) administration in rats. CTX showed rapid excretion and low bioavailability in rats. PMID:25069096

  14. ¹³C labelled internal standards--a solution to minimize ion suppression effects in liquid chromatography-tandem mass spectrometry analyses of drugs in biological samples?

    PubMed

    Berg, Thomas; Strand, Dag Helge

    2011-12-30

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is frequently used to identify and quantify drugs in human biological samples due to the high selectivity and sensitivity of this technique. However, ion suppression effects caused by co-eluting compounds: drugs, metabolites, matrix components, impurities and degradation products, are a major concern. Stable isotope labelled internal standards (SIL ISs), usually deuterium ((2)H) labelled, are often used to compensate for these effects. In many LC separations the retention times of (2)H labelled ISs and their analogues will differ. Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is increasingly being used for bio-analysis. With the better chromatographic resolution provided with sub 2 μm particles, larger separation between analytes and their (2)H labelled analogues can be expected, which might reduce the benefits of the SIL IS. There is a greater difference in physico-chemical properties between hydrogen isotopes than between isotopes of other elements. (13)C, (15)N and (18)O labelled ISs are more similar to their analytes than (2)H labelled ISs and thereby expected to behave more similarly in chromatographic separations. In this study we have investigated the use of (13)C and (2)H labelled ISs for the determination of amphetamine and methamphetamine by UPLC-MS/MS. The (13)C labelled ISs were co eluting with their analytes under different chromatographic conditions while the (2)H labelled ISs and their analytes were slightly separated. An improved ability to compensate for ion suppression effects were observed when the (13)C labelled ISs were used. Furthermore, an UPLC-MS/MS method for determination of amphetamine and methamphetamine in urine using (13)C labelled ISs has been developed and validated. Unfortunately, there are few (13)C labelled ISs commercial available today. If more (13)C labelled ISs become commercial available they may well be the coming solution to minimize

  15. In vitro enantioselective metabolism of TJ0711 hydrochloride by human liver microsomes using a novel chiral liquid chromatography-tandem mass spectrometry method.

    PubMed

    Huang, Jiangeng; Hu, Lei; Xu, Li; Sun, Minghui; Fan, Zhaoze; Qiu, Jun; Li, Gao; Si, Luqin

    2012-04-01

    A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method employing chiral analytical techniques was developed and validated for in vitro enantioselective metabolic stability study of racemic 1-[4-(2-methoxyethyl) phenoxy]-3-[[2-(2-methoxyphenoxy) ethyl]amino]-2-propanol hydrochloride (TJ0711 HCl), a newly developed vasodilatory β-blocker. Robust enantiomeric separations were achieved on a chiral SUMICHIRAL OA-2500 column using ethanol and hexane (40:60, v/v) as a mobile phase. Metabolic stability results demonstrated that both TJ0711 enantiomers underwent a rapid phase I metabolism, but preferential metabolism of R-TJ0711 was observed. Our previously reported ultra-performance liquid chromatography-multiple reaction monitoring-information dependent acquisition-enhanced product ion (UPLC-MRM-IDA-EPI) method was finally chosen for metabolite profiling study of TJ0711 enantiomers, because the newly developed HPLC-based method resulted in compromised chromatographic separation, particularly for TJ0711 metabolites. A number of metabolic products were detected and the structures of formed metabolites were predicted. Similar to racemic TJ0711 HCl, demethylation and hydroxylation were proposed to be the principle metabolism pathways during in vitro incubations of each enantiomer with human liver microsomes. PMID:22406105

  16. A multi-residue method for 17 anticoccidial drugs and ractopamine in animal tissues by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry.

    PubMed

    Matus, Johanna L; Boison, Joe O

    2016-05-01

    A new and sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QToF-MS) method was developed and validated for the determination and confirmation of residues of 17 anticoccidials, plus free ractopamine in poultry muscle and liver, and bovine muscle, liver, and kidney tissues. The 17 anticoccidials are lasalocid, halofuginone, narasin, monensin, semduramicin, ethopabate, robenidine, buquinolate, toltrazuril as its sulfone metabolite, maduramicin, salinomycin, diclazuril, amprolium, decoquinate, dinitolmide, clopidol, and the nicarbazin metabolite DNC (N,N1-bis(4-nitrophenyl)urea). The analytes were extracted and cleaned up within a 3-hour period by simply extracting the analytes into a solvent mixture with salts followed by centrifugation, dilution, and filtration. The validated method was used in a pilot study for the analysis of 173 samples that included quail liver, bovine kidney, liver, muscle, and horse muscle. The predominant residues found in this study were monensin, ractopamine, and lasalocid. The results of this pilot study showed that this new method is applicable to real samples, and is fit for use in a regulatory testing programme. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd. PMID:27443201

  17. Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Homocysteine in Rat Plasma: Application to the Study of a Rat Model for Tauopathies.

    PubMed

    Kovac, Andrej; Svihlova, Katarina; Michalicova, Alena; Novak, Michal

    2015-07-01

    Hyperhomocysteinemia is a common occurrence in many neurodegenerative diseases, including tauopathies. We developed and validated a simple and sensitive liquid chromatography-tandem mass spectrometry method for the analysis of homocysteine (Hcy) in rat plasma. Hcy was analyzed using ultra-performance liquid chromatography on a C8 column with detection by positive ESI tandem mass spectrometry. For optimal retention and separation, we used ion-pair reagent-heptafluorobutyric acid. The method utilizes heavy labeled internal standard and does not require any derivatization or extraction step. The procedure was validated in compliance with the European Medicines Agency guideline. The limit of detection was 0.15 µmol/L and the limit of quantification was 0.5 µmol/L. The method showed excellent linearity with regression coefficients higher than 0.99. The accuracy was in the range of 93-98%. The inter-day precision (n = 5 days), expressed as % relative standard deviation, was in the range 3-8%. Using this method, we analyzed plasma samples from two transgenic lines of the rat model for tauopathies. PMID:25466230

  18. Simultaneous microdetermination of bosentan, ambrisentan, sildenafil, and tadalafil in plasma using liquid chromatography/tandem mass spectrometry for pediatric patients with pulmonary arterial hypertension.

    PubMed

    Yokoyama, Yoshinari; Tomatsuri, Miho; Hayashi, Hideki; Hirai, Keita; Ono, Yasuo; Yamada, Yuto; Todoroki, Kenichiro; Toyo'oka, Toshimasa; Yamada, Hiroshi; Itoh, Kunihiko

    2014-02-01

    A simultaneous, selective, sensitive, and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of bosentan, ambrisentan, sildenafil, and tadalafil in 50μL of human blood plasma. Diluted plasma samples were extracted using a solid-phase extraction procedure with 2% formic acid and methanol. The four drugs were separated by high-performance liquid chromatography using a C18 column and an isocratic mobile phase running at a flow rate of 0.2mL/min for 5min. The drugs were detected by a tandem mass spectrometer with electrospray ionization using deuterated compounds as internal standards. Calibration curves were generated over the linear concentration range of 2-1000ng/mL in plasma with a lower limit of quantification of 2ng/mL for all compounds. Finally, this validated method was applied to a clinical pharmacokinetic study in pediatric patients with pulmonary arterial hypertension (PAH) following the oral administration of PAH drugs. These results indicate that this method is suitable for assessing the risk/benefit of combination therapy in the pediatric population and useful for therapeutic drug monitoring for PAH treatment. PMID:24309556

  19. High-throughput sample preparation and simultaneous column regeneration liquid chromatography-tandem mass spectrometry method for determination of nitrogen mustard metabolites in human urine.

    PubMed

    Reddy, Muntha K; Mills, Grier; Nixon, Christopher; Wyatt, Shane A; Croley, Timothy R

    2011-08-15

    Nitrogen mustards (NMs) are known to have DNA alkylation and strong vesicant properties. Their availability to terrorist organizations makes them a potential choice for chemical attacks on civilian populations. After an exposure, it is difficult to measure NMs directly because of their rapid metabolism in the human body. Therefore to determine an individual's level of exposure to NMs, it is necessary to analyze for NM metabolites being excreted by the body. The metabolites of NMs are generated by a hydrolysis reaction, and are easily detectable by liquid chromatography tandem mass spectrometry (LC-MS/MS). This work is focused on the development of a high-throughput assay for the quantitation of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) metabolites of bis (2-chloroethyl) ethylethanamine (HN1) and bis (2-chloroethyl) methylethanamine (HN2), respectively. The method uses automated 96-well plate sample preparation of human urine samples and a 2-position 10-port switching valve to allow for simultaneous regeneration of the liquid chromatography (LC) columns. Using this method, over 18 h was saved through the reduction of sample preparation and analysis time when compared to a conventional method for 96 samples. The validated method provided excellent accuracy for both EDEA (100.9%) and MDEA (100.6%) with precision better than 5.27% for each analyte. PMID:21764395

  20. Rapid determination of cocamidopropyl betaine impurities in cosmetic products by core-shell hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Perry G; Zhou, Wanlong

    2016-08-26

    Cocamidopropyl betaine (CAPB) is a common surfactant widely used in personal care products. Dimethylaminopropylamine (DMAPA) and lauramidopropyldimethylamine (LAPDMA) are two chemicals present as impurities in CAPB and have been reported as skin sensitizers. A rapid and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method, using a core shell hydrophilic interaction liquid chromatography (HILIC) column, has been developed to quantify DMAPA and LAPDMA in cosmetic products. Corresponding stable isotopically labeled analogues of the above native compounds were used as internal standards to compensate for matrix effect and for loss of recovery. Each sample was first screened to determine whether the sample needed to be diluted to minimize matrix effects as well as to fit the calibration range. The concept of matrix effect factor (MEF) was introduced to quantitatively evaluate each sample with a unique matrix using the internal standards. Recoveries at three spiking levels of low, medium, and high concentrations ranged from 98.4 to 112% with RSDs less than 5%. This method has been validated and is the first UHPLC-MS/MS method, which uses core shell HILIC column and stable isotopically labeled internal standards to simultaneously determine these two CAPB impurities in cosmetic products. PMID:27473511

  1. Identification and discrimination of three common Aloe species by high performance liquid chromatography-tandem mass spectrometry coupled with multivariate analysis.

    PubMed

    Zhao, Yan; Sun, Ya Nan; Lee, Min Jung; Kim, Young Ho; Lee, Wonjae; Kim, Kyeong Ho; Kim, Kyung Tae; Kang, Jong Seong

    2016-09-15

    Aloe arborescens, Aloe barbadensis and Aloe ferox are the most widely cultivated and used among 500 aloe species due to their potent bioactivity. However, the difference of aloe species is neglected and labeled only one name Aloe in the market without specifying aloe species discrimination in general. Furthermore, differences in bioactivity and side effects from different aloe species have not been well investigated. This study develops an effective method for simultaneous qualitative and quantitative determination of three common aloe species using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and high performance liquid chromatography-diode array detection (HPLC-DAD). The extraction conditions were optimized by response surface methodology (RSM) based on methanol concentration, extraction time and solvent-to-material ratio. A partial least squares-discriminant analysis (PLS-DA) was used to identify the three aloe species. The developed HPLC-MS/MS method coupled with multivariate analysis can be applied to discriminate three aloe species successfully. PMID:27494280

  2. Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Quantitation of Microcystins in Blue-Green Algal Dietary Supplements.

    PubMed

    Parker, Christine H; Stutts, Whitney L; DeGrasse, Stacey L

    2015-12-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous detection and quantitation of seven microcystin congeners (1-7) and nodularin-R (8) in blue-green algal dietary supplements. Single-laboratory method validation data were collected in four supplement matrices (capsule, liquid, powder, and tablet) fortified at toxin concentrations from 0.25-2.00 μg/g (ppm). Average recoveries and relative standard deviations (RSD) using matrix-corrected solvent calibration curves were 101% (6% RSD) for all congeners and supplements investigated. Limits of detection (0.006-0.028 μg/g) and quantitation (0.018-0.084 μg/g) were sufficient to confirm the presence of microcystin contamination at the Oregon-mandated guidance concentration of 1.0 μg of microcystin-LReq/g. Quantitated concentrations of microcystin contamination in market-available Aphanizomenon flos-aquae blue-green algal supplements ranged from 0.18-1.87 μg of microcystin-LReq/g for detected congeners microcystin-LR, microcystin-LA, and microcystin-LY (3-5). Microcystin-RR, -YR, -LW, and -LF and nodularin-R (1, 2, and 6-8) were not detected in the supplements examined. PMID:26466789

  3. Optimization of Sample Preparation for the Identification and Quantification of Saxitoxin in Proficiency Test Mussel Sample using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Harju, Kirsi; Rapinoja, Marja-Leena; Avondet, Marc-André; Arnold, Werner; Schär, Martin; Burrell, Stephen; Luginbühl, Werner; Vanninen, Paula

    2015-01-01

    Saxitoxin (STX) and some selected paralytic shellfish poisoning (PSP) analogues in mussel samples were identified and quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction and purification methods of mussel sample were optimized for LC-MS/MS analysis. The developed method was applied to the analysis of the homogenized mussel samples in the proficiency test (PT) within the EQuATox project (Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk). Ten laboratories from eight countries participated in the STX PT. Identification of PSP toxins in naturally contaminated mussel samples was performed by comparison of product ion spectra and retention times with those of reference standards. The quantitative results were obtained with LC-MS/MS by spiking reference standards in toxic mussel extracts. The results were within the z-score of ±1 when compared to the results measured with the official AOAC (Association of Official Analytical Chemists) method 2005.06, pre-column oxidation high-performance liquid chromatography with fluorescence detection (HPLC-FLD). PMID:26610567

  4. Optimization of Sample Preparation for the Identification and Quantification of Saxitoxin in Proficiency Test Mussel Sample using Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Harju, Kirsi; Rapinoja, Marja-Leena; Avondet, Marc-André; Arnold, Werner; Schär, Martin; Burrell, Stephen; Luginbühl, Werner; Vanninen, Paula

    2015-12-01

    Saxitoxin (STX) and some selected paralytic shellfish poisoning (PSP) analogues in mussel samples were identified and quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction and purification methods of mussel sample were optimized for LC-MS/MS analysis. The developed method was applied to the analysis of the homogenized mussel samples in the proficiency test (PT) within the EQuATox project (Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk). Ten laboratories from eight countries participated in the STX PT. Identification of PSP toxins in naturally contaminated mussel samples was performed by comparison of product ion spectra and retention times with those of reference standards. The quantitative results were obtained with LC-MS/MS by spiking reference standards in toxic mussel extracts. The results were within the z-score of ±1 when compared to the results measured with the official AOAC (Association of Official Analytical Chemists) method 2005.06, pre-column oxidation high-performance liquid chromatography with fluorescence detection (HPLC-FLD). PMID:26610567

  5. Liquid chromatography-tandem mass spectrometric assay for the PI3K/mTOR inhibitor GSK2126458 in mouse plasma and tumor homogenate.

    PubMed

    Dolman, M Emmy M; Westerhout, Ellen M; Hamdi, Mohamed; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2015-03-25

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for GSK2126458, a dual PI3K/mTOR inhibitor, was developed and validated. Plasma and tumor homogenate samples were pre-treated using protein precipitation with acetonitrile containing dabrafenib as internal standard. After dilution with water, the extract was directly injected into the reversed-phase liquid chromatographic system. The eluate was transferred into the electrospray interface with positive ionization and compounds were detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was completely validated for plasma in a 4-4000 ng/ml calibration range with r(2)=0.9996±0.0003 using double logarithmic calibration (n=5). Within-run precisions (n=6) were 2.0-5.3% and between-run (3 runs; n=18) precisions 2.7-5.8%. Accuracies were between 101 and 105% for the whole calibration range. The drug was sufficiently stable under all relevant analytical conditions. Finally, the assay was successfully applied to determine plasma and tumor drug levels after oral administration of GSK2126458 to mice with AMC711T neuroblastoma xenografts. PMID:25659532

  6. Development of a method for the analysis of underivatized amino acids by liquid chromatography/tandem mass spectrometry: application on Standard Reference Material 1649a (urban dust).

    PubMed

    Buiarelli, Francesca; Gallo, Valentina; Di Filippo, Patrizia; Pomata, Donatella; Riccardi, Carmela

    2013-10-15

    A liquid chromatography-tandem mass spectrometry analytical procedure has been developed for the detection and quantitative determination of underivatized amino acids at low concentrations in a Standard Reference Material-urban dust. In order to minimize interferences of other compounds, an accelerated solvent extraction followed by a solid phase extraction on two different cartridges was applied prior to LC-MS-MS. Fourteen amino acids were separated by high resolution liquid chromatography, detected and quantified by multiple reaction monitoring on a triple quadrupole. The proposed methodology has been applied for the first time on Standard Reference Material 1649a (urban dust) from the National Institute of Standards and Technology, that does not report certification values for these compounds. This methodology avoids the derivatization step and allows the amino acid quantification in a complex matrix, such as that of atmospheric particulate matter, and represent a good method suitable to analyze this class of compounds in atmospheric aerosol. The selected strategy demonstrated to be fit-for-purpose, by applying it to a real atmospheric sample with the aim to verify the efficacy of the study and to provide information about the organic matter content. PMID:24054689

  7. Determination of acrylamide in coffee and chocolate by pressurised fluid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Pardo, O; Yusà, V; Coscollà, C; León, N; Pastor, A

    2007-07-01

    A selective and sensitive procedure has been developed and validated for the determination of acrylamide in difficult matrices, such as coffee and chocolate. The proposed method includes pressurised fluid extraction (PFE) with acetonitrile, florisil clean-up purification inside the PFE extraction cell and detection by liquid chromatography (LC) coupled to atmospheric pressure ionisation in positive mode tandem mass spectrometry (APCI-MS-MS). Comparison of ionisation sources (atmospheric pressure chemical ionisation (APCI), atmospheric pressure photoionization (APPI) and the combined APCI/APPI) and clean-up procedures were carried out to improve the analytical signal. The main parameters affecting the performance of the different ionisation sources were previously optimised using statistical design of experiments (DOE). PFE parameters were also optimised by DOE. For quantitation, an isotope dilution approach was used. The limit of quantification (LOQ) of the method was 1 microg kg(-1) for coffee and 0.6 microg kg(-1) for chocolate. Recoveries ranged between 81-105% in coffee and 87-102% in chocolate. The accuracy was evaluated using a coffee reference test material FAPAS T3008. Using the optimised method, 20 coffee and 15 chocolate samples collected from Valencian (Spain) supermarkets, were investigated for acrylamide, yielding median levels of 146 microg kg(-1) in coffee and 102 microg kg(-1) in chocolate. PMID:17613050

  8. Fast and reliable artemisinin determination from different Artemisia annua leaves based alimentary products by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Carrà, Andrea; Bagnati, Renzo; Fanelli, Roberto; Bonati, Maurizio

    2014-01-01

    In many tropical countries malaria is endemic, causing acute illness and killing people, especially children. The availability of recommended malaria medicines is scant, even though these medicines are based on artemisinin, a compound extracted from the Artemisia annua plant that grows in many of these countries. New sources of treatment drawn from traditional medicine are therefore used, such as the tea infusion. An analytical method based on high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) was developed to quantify the artemisinin content of foods prepared with Artemisia annua leaves. A fast and reliable analytical method is described. The technique does not require any derivatisation prior to injection and offers excellent analytical intermediate precision. Robust qualitative and quantitative results were obtained using tea, biscuit or porridge specimens. Although further research is needed to define the potential therapeutic benefits of these alimentary formulations, the analytical method described can be employed in developing more convenient and appropriate foods for administering artemisinin to those infected with malaria. PMID:24001820

  9. Simultaneous determination of 15 steroidal oral contraceptives in water using solid-phase disk extraction followed by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Sun, Li; Yong, Wei; Chu, Xiaogan; Lin, Jin-Ming

    2009-07-10

    A rapid, accurate and sensitive method for simultaneous determination of 15 steroidal hormones including four estrogens (estrone, 17beta-estradiol, 17alpha-ethynylestradiol, estriol) and eleven progestogens (17beta-estradiol-3-benzoate, 19-norethindrone, gestodene, levonorgestrel, medroxyprogesterone, cyproterone acetate, megestrol-17-acetate, progesterone, norethindrone acetate, chlormadinone-17-acetate, and hydroxy progesterone caproate) in environmental waters was developed by coupling solid-phase disk extraction (SPDE) to ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with electrospray ionization. Among three types of extraction tested (C(8) SPDE, C(18) SPDE and C(18) SPE), the most satisfactory result was achieved using C(18) SPDE for its satisfactory recovery (75.6 to 101.4%) and short extraction time (15 min for 1L deionised water). The validity of this method was investigated and good analytical performance for all the analytes was obtained, including low limits of method detection (0.5-3.4 ng/L) and excellent linear dynamic range (1.0-50.0 ng/L). The method was applied to determine the steroidal hormones in 10 environmental waters including tap water, river water, lake water and waste water in Beijing. No progestogen was detected in all samples and estrone, estriol, 17alpha-ethynylestradiol were found in most samples at levels between 1.8 and 127.9 ng/L. PMID:19497575

  10. Determination of six chemotherapeutic agents in municipal wastewater using online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry.

    PubMed

    Rabii, Farida W; Segura, Pedro A; Fayad, Paul B; Sauvé, Sébastien

    2014-07-15

    Due to the increased consumption of chemotherapeutic agents, their high toxicity, carcinogenicity, their occurrence in the aquatic environment must be properly evaluated. An analytical method based on online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry was developed and validated. A 1 mL injection volume was used to quantify six of the most widely used cytotoxic drugs (cyclophosphamide, gemcitabine, ifosfamide, methotrexate, irinotecan and epirubicin) in municipal wastewater. The method was validated using standard additions. The validation results in wastewater influent had coefficients of determination (R(2)) between 0.983 and 0.998 and intra-day precision ranging from 7 to 13% (expressed as relative standard deviation %RSD), and from 9 to 23% for inter-day precision. Limits of detection ranged from 4 to 20 ng L(-1) while recovery values were greater than 70% except for gemcitabine, which is the most hydrophilic compound in the selected group and had a recovery of 47%. Matrix effects were interpreted by signal suppression and ranged from 55 to 118% with cyclophosphamide having the highest value. Two of the target anticancer drugs (cyclophosphamide and methotrexate) were detected and quantified in wastewater (effluent and influent) and ranged from 13 to 60 ng L(-1). The proposed method thus allows proper monitoring of potential environmental releases of chemotherapy agents. PMID:24388503

  11. Evaluation of column carryover of phosphorylated peptides and fumonisins by duplicated solvent gradient method in liquid chromatography/tandem mass spectrometry.

    PubMed

    Sakamaki, Hiroshi; Uchida, Takeharu; Lim, Lee Wah; Takeuchi, Toyohide

    2015-01-01

    Columns made of three different materials were evaluated with regard to the carryover of phosphorylated peptides and fumonisins in liquid chromatography/tandem mass spectrometry (LC/MS/MS). In order to eliminate carryover caused by the injection operation in the autosampler, the column carryover was calculated using the duplicated solvent gradient method. A column made of a glass-lined stainless-steel tube and polyethylene frits (GL-PE column) yielded the most significant improvements in the peak shape and the carryover as compared to the other columns. The carryover of fumonisin B1 (FB1) and HLADLSpK (T19p) in the GL-PE column could be reduced; the lower limit of quantitation of T19p, and the range of the calibration curve were also improved. Since carryover peaks with the GL-PE column were symmetrical peaks of the samples, carryover in the column did not occur. The carryover calculated by the duplicated solvent gradient method corresponded to those in the flow path from the injection port to the inlet frit of the column. The carryover value of FB1 in the column with a stainless-steel tube and stainless-steel frits (S-S column) was 1.70%, and that of the flow path was 0.23%. We found that the majority of the carryover in our system occurred in the S-S column. PMID:25746806

  12. Fast and selective determination of triterpenic compounds in olive leaves by liquid chromatography-tandem mass spectrometry with multiple reaction monitoring after microwave-assisted extraction.

    PubMed

    Sánchez-Avila, N; Priego-Capote, F; Ruiz-Jiménez, J; de Castro, M D Luque

    2009-04-15

    A method for fast and selective determination of the main triterpenic compounds present in olive leaves - oleanolic, ursolic and maslinic acids as triterpenic acids and, uvaol and erythrodiol as triterpenic dialcohols - is reported here. Quantitative isolation of the analytes has been accomplished in 5min by microwave assistance using ethanol as extractant. Due to the medium polarity of triterpenic acids and dialcohols, different ethanol-water ratios were tested in order to select the optimum extractant composition for their solubilisation. Microwave assistance provided a significant shortening of the leaching time as compared to conventional procedures by maceration, which usually requires at least 5h. After extraction, determination was carried out by liquid chromatography-tandem mass spectrometry (LC-MS-MS) with a triple quadrupole (qQq) mass detector without any clean-up step prior to chromatographic analysis. Highly selective identification of triterpenes was confirmed by multiple reaction monitoring (MRM) using the most representative transitions from the precursor ion to the different product ions, while the most sensitive transitions were used for MS-MS quantitation. Total analysis performed in 25 min enables the characterization of a fraction with particular interest in the pharmacological area. PMID:19174200

  13. Direct rapid analysis of multiple PPCPs in municipal wastewater using ultrahigh performance liquid chromatography-tandem mass spectrometry without SPE pre-concentration.

    PubMed

    Yu, Ke; Li, Bing; Zhang, Tong

    2012-08-13

    Ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was utilized to develop a rapid, sensitive and reliable method without solid phase extraction (SPE) pre-concentration for trace analysis of 11 pharmaceuticals and personal care products (PPCPs) in influent and effluent from municipal wastewater treatment plants (WWTPs). This method not only shortened the analysis time but also reduced analysis cost significantly by omitting SPE process and avoiding the consumption of SPE cartridge. Detection parameters for UHPLC-MS/MS analysis were optimized, including sample pH, eluent, mobile phase (solvent and additive), column temperature, and flow rate. Under the optimal conditions, all analytes were well separated and detected within 8.0min by UHPLC-MS/MS. The method quantification limits (MQLs) for the 11 PPCPs ranged from 0.040 to 88ngL(-1) and from 0.030 to 90ngL(-1) for influent and effluent, respectively. The matrix effect was systematically investigated and quantified for different types of samples. The analysis of influent and effluent samples of two WWTPs in Hong Kong revealed the presence of 11 PPCPs, including acyclovir, benzophenone-3, benzylparaben, carbamazepine, ethylparaben, fluconazole, fluoxetine, methylparaben, metronidazole, propylparaben, and ranitidine. Their concentrations ranged from 9.1 to 1810ngL(-1) in influent and from 6.5 to 823ngL(-1) in effluent samples collected from Hong Kong WWTPs. PMID:22790701

  14. A reliable liquid chromatography-tandem mass spectrometry method for simultaneous determination of multiple mycotoxins in fresh fish and dried seafoods.

    PubMed

    Sun, Wenshuo; Han, Zheng; Aerts, Johan; Nie, Dongxia; Jin, Mengtong; Shi, Wen; Zhao, Zhiyong; De Saeger, Sarah; Zhao, Yong; Wu, Aibo

    2015-03-27

    A reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of nine mycotoxins, i.e., aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), ochratoxin A (OTA), zearalenone (ZEN), T-2 toxin, HT2 toxin and deoxynivalenol (DON), in fresh fish (muscle and entrails) as well as dried seafoods. Special focus was given to sample pretreatment which is crucial for an accurate and reliable analytical method. With regards to the high complexity of the matrices, extraction solvent, time, and temperature as well as clean-up cartridges were optimized to improve extraction efficiency and reduce matrix effects. The optimum procedure included ultrasound-assisted extraction with acetonitrile/water/acetic acid (79/20/1, v/v/v) at 40 °C for 30 min, defatting with n-hexane and purification by Oasis HLB cartridges. The method was further validated by determining the linearity (R(2) ≥ 0.9989), sensitivity (limit of detection ≤ 2 μg/kg, limit of quantitation ≤ 3 μg/kg), recovery (72.2-119.9%) and precision (≤ 18.3%) in muscle and entrails of fresh crucian carp (Carassius carassius) as well as dried fish products. The method was proven to be suitable for its intended purposes. Mycotoxins of OTA, ZEN and AFB2 have been found in fresh fish and dried seafoods for the first time. PMID:25711425

  15. A liquid chromatography tandem mass spectrometry method for the simultaneous quantification of 20 drugs of abuse and metabolites in human meconium

    PubMed Central

    Gray, Teresa R.; Shakleya, Diaa M.

    2011-01-01

    A method for the simultaneous quantification of 20 cocaine, amphetamine, opiate, and nicotine analytes in meconium, the first neonatal feces, by liquid chromatography tandem mass spectrometry was developed and validated. Specimen preparation included methanol homogenization and solid phase extraction. Two injections were required to achieve sufficient sensitivity and linear dynamic range. Linearity ranged from 0.5–25 up to 500 ng/g (250 ng/g p-hydroxymethamphetamine), and correlation coefficients were >0.996. Imprecision was <10.0% CV, analytical recovery 85.5–123.1%, and extraction efficiencies >46.7% at three concentrations across the linear range. Despite significant matrix effects of −305.7–40.7%, effects were similar for native and deuterated analytes. No carryover, endogenous or exogenous interferences were observed, with analyte stability at room temperature, 4 °C, and −20 °C and on the autosampler >70%, except for 6-acetylmorphine, hydrocodone, oxycodone, and morphine. Method applicability was demonstrated by analyzing meconium from drug-exposed neonates. PMID:19241063

  16. Simultaneous estimation of E- and Z-isomers of guggulsterone in rabbit plasma using liquid chromatography tandem mass spectrometry and its application to pharmacokinetic study.

    PubMed

    Bhatta, R S; Kumar, D; Chhonker, Y S; Jain, G K

    2011-09-01

    A sensitive and selective liquid chromatography/tandem mass spectrometric method was developed for simultaneous determination of E- and Z-guggulsterone isomers (antihyperlipidemic drug) in rabbit plasma. Both the isomers were resolved on a Symmetry-Shield C(18) (5 µm, 4.6 × 150 mm) column, using gradient elution comprising a mobile phase of methanol, 0.5% v/v formic acid and acetonitrile. With dexamethasone as internal standard, plasma samples were extracted by an automated solid-phase extraction method using C(18) cartridges. Detection was performed by electrospray ionization in multiple reaction monitoring (MRM) in positive mode. The calibration curve was linear over the concentration range of 1.56-200 ng/mL (r(2) ≥ 0.998) for both analytes. The intra-day and inter-day accuracy and precision were within -0.96 to 4.12 (%bias) and 2.73 to 8.00 (%RSD) respectively. The analytes were stable after three freeze-thaw cycles. The method was successfully applied to study steriospecific pharmacokinetics of E- and Z-guggulsterone in NZ rabbit. PMID:21268049

  17. Absolute quantification of Pru av 2 in sweet cherry fruit by liquid chromatography/tandem mass spectrometry with the use of a stable isotope-labelled peptide.

    PubMed

    Ippoushi, Katsunari; Sasanuma, Motoe; Oike, Hideaki; Kobori, Masuko; Maeda-Yamamoto, Mari

    2016-08-01

    Pru av 2, a pathogenesis-related (PR) protein present in the sweet cherry (Prunus avium L.) fruit, is the principal allergen of cherry and one of the chief causes of pollen food syndrome (oral allergy syndrome). In this study, a quantitative assay for this protein was developed with the use of the protein absolute quantification (AQUA) method, which consists of liquid chromatography/tandem mass spectrometry (LC/MS/MS) employing TGC[CAM]STDASGK[(13)C6,(15)N2], a stable isotope-labelled internal standard (SIIS) peptide. This assay gave a linear relationship (r(2)>0.99) in a concentration range (2.3-600fmol/μL), and the overall coefficient of variation (CV) for multiple tests was 14.6%. Thus, the contents of this allergenic protein in sweet cherry products could be determined using this assay. This assay should be valuable for allergological investigations of Pru av 2 in sweet cherry and detection of protein contamination in foods. PMID:26988485

  18. [Simultaneous determination of penicillin and their major enzymatic metabolites in milk and milk powder by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Li, Wei; Ai, Lianfeng; Guo, Chunhai; Ma, Yusong; Dou, Caiyun

    2013-10-01

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method has been developed for the determination of eight compounds in milk and milk powder. They are four penicillins (penicillin G, penicillin V, amoxicillin and ampicillin) and four major beta-lactamase enzymatic metabolites of them (penilloic acid G, penilloic acid V, amoxiilloic acid and ampilloic acid). The compounds were extracted from the samples with acetonitrile and water, cleaned-up by HLB solid-phase extraction cartridges, and then detected by HPLC-MS/MS and quantified by external standard method. The linearities were satisfactory with the correlation coefficients > 0.99 at the mass concentrations ranging from 4 microg/L to 200 microg/L for penicillins and from 10 microg/L to 500 microg/L for enzymatic metabolites. The limits of detection and the limits of quantification were 5-50 microg/kg (S/N > or = 3) and 8-100 microg/kg (S/N > or = 10), respectively. The average recoveries of the eight compounds were 83.48%-96.97% in milk and 82.70%-95.14% in milk powder. The relative standard deviations (RSDs) in milk and milk powder were 3.86%-10.87% and 3.02%-9.81%, respectively. In conclusion, the established method is convenient, accurate and sensitive so that it can be applied to the determination of penicillin residues and enzymatic metabolites in milk and milk powder. PMID:24432636

  19. Dynamic Biodistribution of Icaritin and Its Phase-II Metabolite in Rat Tissues by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Zhang, Shuang-Qing

    2016-01-01

    Icaritin (ICT), a major component in herb Epimedium brevicornum Maxim., shows beneficial effects for the treatment of osteoporosis and various cancers, and is predominantly metabolized to glucuronidated icaritin (GICT). Although clinical trials of ICT have exhibited good safety and tolerance, the dynamic bioditributions of ICT and GICT have not been reported. In the present study, the chemical structure of GICT was firstly reported, and a reliable ultra-high performance liquid chromatography-tandem mass spectrometry method (UHPLC-MS/MS) was firstly established for the simultaneous quantifications of ICT and GICT in rat tissues. The dynamic distribution of ICT and GICT in rat tissues and their pharmacokinetic parameters have been reported for the first time. ICT, GICT and the internal standard coumestrol were separated on a C18 column with a gradient mobile phase of acetonitrile and water containing ammonium formate and formic acid at a flow rate of 0.3 mL min(-1). The analytes were quantified by a triple quadrupole tandem mass spectrometer in the negative ionization mode. The lower limit of quantification values for ICT and GICT were 0.2 and 2 ng mL(-1), respectively. Good selectivity, linearity, accuracy, precision and recovery were achieved, and no significant matrix effect was observed. The UHPLC-MS/MS was firstly applied to a dynamic biodistribution study of ICT and GICT in rats, following an intraperitoneal administration of ICT at a dose of 10 mg kg(-1). PMID:27302583

  20. Evaluation of treadmill exercise effect on muscular lipid profiles of diabetic fatty rats by nanoflow liquid chromatography-tandem mass spectrometry.

    PubMed

    Lee, Jong Cheol; Kim, Il Yong; Son, Yeri; Byeon, Seul Kee; Yoon, Dong Hyun; Son, Jun Seok; Song, Han Sol; Song, Wook; Seong, Je Kyung; Moon, Myeong Hee

    2016-01-01

    We compare comprehensive quantitative profiling of lipids at the molecular level from skeletal muscle tissues (gastrocnemius and soleus) of Zucker diabetic fatty rats and Zucker lean control rats during treadmill exercise by nanoflow liquid chromatography-tandem mass spectrometry. Because type II diabetes is caused by decreased insulin sensitivity due to excess lipids accumulated in skeletal muscle tissue, lipidomic analysis of muscle tissues under treadmill exercise can help unveil the mechanism of lipid-associated insulin resistance. In total, 314 lipid species, including phospholipids, sphingolipids, ceramides, diacylglycerols (DAGs), and triacylglycerols (TAGs), were analyzed to examine diabetes-related lipid species and responses to treadmill exercise. Most lysophospholipid levels increased with diabetes. While DAG levels (10 from the gastrocnemius and 13 from the soleus) were >3-fold higher in diabetic rats, levels of most of these decreased after exercise in soleus but not in gastrocnemius. Levels of 5 highly abundant TAGs (52:1 and 54:3 in the gastrocnemius and 48:2, 50:2, and 52:4 in the soleus) displaying 2-fold increases in diabetic rats decreased after exercise in the soleus but not in the gastrocnemius in most cases. Thus, aerobic exercise has a stronger influence on lipid levels in the soleus than in the gastrocnemius in type 2 diabetic rats. PMID:27388225

  1. Simultaneous quantification of olanzapine and its metabolite N-desmethylolanzapine in human plasma by liquid chromatography tandem mass spectrometry for therapeutic drug monitoring.

    PubMed

    Lou, Hong-gang; Ruan, Zou-rong; Jiang, Bo; Chen, Jin-liang

    2015-05-01

    A simple, sensitive, and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantification of olanzapine (OLZ) and its metabolite N-desmethylolanzapine (DMO) in human plasma for therapeutic drug monitoring. Sample preparation was performed by one-step protein precipitation with methanol. The analytes were chromatographed on a reversed-phase YMC-ODS-AQ C18 Column (2.0 × 100 mm,3 µm) by a gradient program at a flow rate of 0.30 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer via electrospray ionization in positive ion mode. The method was validated for selectivity, linearity, accuracy, precision, matrix effect, recovery and stability. The calibration curve was linear over the concentration range 0.2-120 ng/mL for OLZ and 0.5-50 ng/mL for DMO. Intra- and interday precisions for OLZ and DMO were <11.29%, and the accuracy ranged from 95.23 to 113.16%. The developed method was subsequently applied to therapeutic drug monitoring for psychiatric patients receiving therapy of OLZ tablets. The method seems to be suitable for therapeutic drug monitoring of patients undergoing therapy with OLZ and might contribute to prediction of the risk of adverse reactions. PMID:25297964

  2. Confirmation of 13 sulfonamides in honey by liquid chromatography-tandem mass spectrometry for monitoring plans: validation according to European Union Decision 2002/657/EC.

    PubMed

    Dubreil-Chéneau, Estelle; Pirotais, Yvette; Verdon, Eric; Hurtaud-Pessel, Dominique

    2014-04-25

    A rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous confirmation of 13 sulfonamides in honey was developed and fully validated in accordance with the European Commission Decision No 2002/657/EC. The validation scheme was built in accordance with the target level of 50μgkg(-1) for all analytes. The sulfonamides investigated were as follows: sulfaguanidine (SGN), sulfanilamide (SNL), sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethizole (SMZ), sulfadimerazine (SDM), sulfamonomethoxine (SMNM), sulfamethoxypiridazine (SMP), sulfadoxine (SDX), sulfamethoxazole (SMX), sulfaquinoxaline (SQX) and sulfadimethoxine (SDT). Several extraction procedures were investigated during the development phase. Finally, the best results were obtained with a procedure using acidic hydrolysis and cation exchange purification. Chromatographic separation was achieved on a C18 analytical column. Matrix effects were also investigated. Data acquisition implemented for the confirmatory purpose was performed by monitoring 2 MRM transitions per analyte under the positive electrospray mode. Mean relative recoveries ranged from 85.8% to 110.2% and relative standard deviations lying between 2.6% and 19.8% in intra-laboratory reproducibility conditions. The decision limits (CCα) ranged from 1.8 to 15.5μgkg(-1). High resolution mass spectrometry was used to investigate the possible formation of sulfonamide metabolites in honey. The validation results proved that the method is suitable for the screening and confirmatory steps as implemented for the French monitoring residue plan for sulfonamides residue control in honeybees. PMID:24666935

  3. Determination of eight sulfonamides in bovine kidney by liquid chromatography/tandem mass spectrometry with on-line extraction and sample clean-up.

    PubMed

    Van Eeckhout, N; Perez, J C; Van Peteghem, C

    2000-01-01

    A sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass spectrometry/mass spectrometry; LC/MS/MS) method with on-line extraction and sample clean-up for the screening and confirmation of residues of sulfonamides in kidney is described. The sulfonamides are extracted from homogenized kidney with methanol. After centrifugation of the extract, an aliquot of the extract is directly injected on the LC/MS/MS system with further extraction and clean-up of the sample on-line. Detection of the analytes was achieved by positive electrospray ionization (ESI) followed by multiple reaction monitoring. For each sulfonamide the collisional decomposition of the protonated molecule to a common, abundant fragment ion was monitored. The method has been validated for sulfadimethoxine, sulfaquinoxaline, sulfamethazine, sulfamerazine, sulfathiazole, sulfamethoxazole, sulfadiazine and sulfapyridine. Calibration curves resulting from spiked blank kidney samples at the 10-200 microg/kg level showed good linear correlation. At the level of 50, 100 and 200 microg/kg both within- and between-day precision, as measured by relative standard deviation (RSD), were less than 16%. The limits of detection (LODs) ranged from 5 to 13.5 microg/kg. The recoveries ranged from 78 to 82%. The procedure provides a rapid, reliable and sensitive method for the determination of residues of sulfonamides in bovine kidney. The advantage of this method over existing methods is its decreased sample preparation and analysis time, which makes the method more suitable for routine analysis. PMID:11114046

  4. Development and validation of a high-performance liquid chromatography-tandem mass spectrometric method for simultaneous determination of bupropion, quetiapine and escitalopram in human plasma.

    PubMed

    Park, Semin; Park, Chul-Soo; Lee, Sung Joong; Cha, Boseok; Cho, Young Ah; Song, Yi; Yu, Eun Ae; Kim, Gon-Sup; Jin, Jong Sung; Abd El-Aty, A M; El-Banna, H A; Hacımüftüoğlu, Ahmet; Shim, Jae-Han; Shin, Sung Chul

    2015-04-01

    In the present study, an effective high performance liquid chromatography-tandem mass spectrometric (HPLC/MS/MS) method was developed and validated to simultaneously determine bupropion (BUP), quetiapine (QUE) and escitalopram (ESC) in human plasma using carbidopa as the internal standard. Chromatographic separation was achieved on a Waters Sun Fire C18 column using reversed-phase chromatography. The MS/MS experiment was performed in positive ion multiple reaction monitoring mode to produce product ions of m/z 240.3 → 184.2 for BUP, 384.2 → 253.1 for QUE, 325.3 → 109.3 for ESC and 227.2 → 181.2 for the internal standard. The method showed good linearity (R(2)  ≥ 0.997), precision (relative standard deviation ≤7.5%), satisfactory intra- and interday accuracy (88.4-113.0%) and acceptable extraction recovery (87.2-115.0%), matrix effect (84.5.5-108.7%) and stability (92.3-103.5%). The method was successfully applied to determine the concentrations of BUP, QUE and ESC in human plasma samples. PMID:25262603

  5. Development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of tigecycline in rat brain tissues.

    PubMed

    Munyeza, Chiedza F; Shobo, Adeola; Baijnath, Sooraj; Bratkowska, Dominika; Naiker, Suhashni; Bester, Linda A; Singh, Sanil D; Maguire, Glenn E M; Kruger, Hendrik G; Naicker, Tricia; Govender, Thavendran

    2016-06-01

    Tigecycline (TIG), a derivative of minocycline, is the first in the novel class of glycylcyclines and is currently indicated for the treatment of complicated skin structure and intra-abdominal infections. A selective, accurate and reversed-phase high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of TIG in rat brain tissues. Sample preparation was based on protein precipitation and solid phase extraction using Supel-Select HLB (30 mg/1 mL) cartridges. The samples were separated on a YMC Triart C18 column (150 mm x 3.0 mm. 3.0 µm) using gradient elution. Positive electrospray ionization (ESI+) was used for the detection mechanism with the multiple reaction monitoring (MRM) mode. The method was validated over the concentration range of 150-1200 ng/mL for rat brain tissue. The precision and accuracy for all brain analyses were within the acceptable limit. The mean extraction recovery in rat brain was 83.6%. This validated method was successfully applied to a pharmacokinetic study in female Sprague Dawley rats, which were given a dose of 25 mg/kg TIG intraperitoneally at various time-points. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26378888

  6. Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Nahar, Limon Khatun; Cordero, Rosa Elena; Nutt, David; Lingford-Hughes, Anne; Turton, Samuel; Durant, Claire; Wilson, Sue; Paterson, Sue

    2016-03-01

    A highly sensitive and fully validated method was developed for the quantification of baclofen in human plasma. After adjusting the pH of the plasma samples using a phosphate buffer solution (pH 4), baclofen was purified using mixed mode (C8/cation exchange) solid-phase extraction (SPE) cartridges. Endogenous water-soluble compounds and lipids were removed from the cartridges before the samples were eluted and concentrated. The samples were analyzed using triple-quadrupole liquid chromatography-tandem mass spectrometry (LC-MS-MS) with triggered dynamic multiple reaction monitoring mode for simultaneous quantification and confirmation. The assay was linear from 25 to 1,000 ng/mL (r(2) > 0.999; n = 6). Intraday (n = 6) and interday (n = 15) imprecisions (% relative standard deviation) were <5%, and the average recovery was 30%. The limit of detection of the method was 5 ng/mL, and the limit of quantification was 25 ng/mL. Plasma samples from healthy male volunteers (n = 9, median age: 22) given two single oral doses of baclofen (10 and 60 mg) on nonconsecutive days were analyzed to demonstrate method applicability. PMID:26538544

  7. Within-laboratory validation of a multiresidue method for the analysis of 98 pesticides in mango by liquid chromatography-tandem mass spectrometry.

    PubMed

    Fleury Filho, N; Nascimento, C A; Faria, E O; Cruvinel, A R; Oliveira, J M

    2012-01-01

    A within-laboratory validation procedure for a selective and sensitive method for the simultaneous determination of 98 pesticide residues in mango is presented. QuEChERS extraction was adapted to laboratory conditions. Mango samples (10 g) mixed with sodium sulfate (4 g) and sodium acetate (1 g) were extracted with acetonitrile/acetic acid (99/1 v/v), cleaned using dispersive solids, and subsequently identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pesticides were separated on a reversed-phase column using a gradient elution in conjunction with positive-mode electrospray ionisation. The analytical performance of the method was demonstrated by analysis of spiked mango samples at three concentration levels (0.01, 0.05 and 0.1 mg kg(-1)) for 3 different days, and the analysis was performed by three analysts. Calibration curves were statistically acceptable by the ordinary last-square method (OLSM), with a regression coefficient above 0.98 for all analytes. The method accuracy (n = 18) was between 80% and 110%, and precisions were below 20% for 95% of the analytes. The method uncertainty at the LOQ was evaluated considering the uncertainty associated with the calibration curve and the uncertainty associated with the method precision. The validation data for all pesticides were in accordance with Brazilian and European guidelines for pesticide residue analysis. PMID:22014095

  8. Analysis of advanced glycation endproducts in selected food items by ultra-performance liquid chromatography tandem mass spectrometry: Presentation of a dietary AGE database.

    PubMed

    Scheijen, Jean L J M; Clevers, Egbert; Engelen, Lian; Dagnelie, Pieter C; Brouns, Fred; Stehouwer, Coen D A; Schalkwijk, Casper G

    2016-01-01

    The aim of this study was to validate an ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the determination of advanced glycation endproducts (AGEs) in food items and to analyze AGEs in a selection of food items commonly consumed in a Western diet. N(ε)-(carboxymethyl)lysine (CML), N(ε)-(1-carboxyethyl)lysine (CEL) and N(δ)-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were quantified in the protein fractions of 190 food items using UPLC-MS/MS. Intra- and inter-day accuracy and precision were 2-29%. The calibration curves showed perfect linearity in water and food matrices. We found the highest AGE levels in high-heat processed nut or grain products, and canned meats. Fruits, vegetables, butter and coffee had the lowest AGE content. The described method proved to be suitable for the quantification of three major AGEs in food items. The presented dietary AGE database opens the possibility to further quantify actual dietary exposure to AGEs and to explore its physiological impact on human health. PMID:26213088

  9. Survey of Deoxynivalenol and Aflatoxin B1 in Instant Noodles and Bread Consumed in Thailand by Using Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Pralatnet, Sasithorn; Poapolathep, Saranya; Giorgi, Mario; Imsilp, Kanjana; Kumagai, Susumu; Poapolathep, Amnart

    2016-07-01

    One hundred wheat product samples (50 instant noodle samples and 50 bread samples) were collected from supermarkets in Bangkok, Thailand. Deoxynivalenol (DON) and aflatoxin B1 (AFB1) contamination in these products was analyzed using a validated liquid chromatography-tandem mass spectrometry method. The limit of quantification values of DON and AFB1 in the instant noodles and bread were 2 and 1 ng g(-1), respectively. The survey found that DON was quantifiable in 40% of collected samples, in 2% of noodles (0.089 μg g(-1)), and in 78% of breads (0.004 to 0.331 μg g(-1)). AFB1 was below the limit of quantification of the method in all of the tested samples. The results suggest that the risk of DON exposure via noodles and breads is very low in urban areas of Thailand. No risk can be attributable to AFB1 exposure in the same food matrices, but further studies with a larger sample size are needed to confirm these data. PMID:27357050

  10. Use of Imipenem To Detect KPC, NDM, OXA, IMP, and VIM Carbapenemase Activity from Gram-Negative Rods in 75 Minutes Using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Kulkarni, M. V.; Zurita, A. N.; Pyka, J. S.; Murray, T. S.; Hodsdon, M. E.

    2014-01-01

    Resistance to extended-spectrum β-lactam antibiotics has led to a greater reliance upon carbapenems, but the expression of carbapenemases threatens to limit the utility of these drugs. Current methods to detect carbapenemase activity are suboptimal, requiring prolonged incubations during which ineffective therapy may be prescribed. We previously described a sensitive and specific assay for the detection of carbapenemase activity using ertapenem and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we assessed 402 Gram-negative rods, including both Enterobacteriaceae and non-Enterobacteriaceae expressing IMP, VIM, KPC, NDM, and/or OXA carbapenemases, by using imipenem, meropenem, and ertapenem with LC-MS/MS assays. LC-MS/MS methods for the detection of intact and hydrolyzed carbapenems from an enrichment broth were developed. No ion suppression was observed, and the limits of detection for all three drugs were below 0.04 μg/ml. The sensitivity and specificity of meropenem and ertapenem for carbapenemase activity among non-Enterobacteriaceae were low, but imipenem demonstrated a sensitivity and specificity of 96% and 95%, respectively, among all Gram-negative rods (GNR) tested, including both Enterobacteriaceae and non-Enterobacteriaceae. LC-MS/MS allows for the analysis of more complex matrices, and this LC-MS/MS assay could easily be adapted for use with primary specimens requiring growth enrichment. PMID:24789180

  11. Rapid determination of glyphosate, glufosinate, bialaphos, and their major metabolites in serum by liquid chromatography-tandem mass spectrometry using hydrophilic interaction chromatography.

    PubMed

    Yoshioka, Naoki; Asano, Migiwa; Kuse, Azumi; Mitsuhashi, Takao; Nagasaki, Yasushi; Ueno, Yasuhiro

    2011-06-10

    We developed a simple and rapid method for the simultaneous determination of phosphorus-containing amino acid herbicides (glyphosate, glufosinate, bialaphos) and their major metabolites, aminomethylphosphonic acid (AMPA) and 3-methylphosphinicopropionic acid (MPPA), in human serum. Serum samples were filtrated through an ultrafiltration membrane to remove proteins. The filtrate was then washed with chloroform, and injected into a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. Chromatographic separation was achieved on a hydrophilic interaction chromatography (HILIC) column. Determination of the target herbicides and metabolites was successfully carried out without derivatization or solid phase extraction (SPE) cartridge clean-up. The recoveries of these compounds, added to human serum at 0.2μg/mL, ranged from 94% to 108%, and the relative standard deviations (RSDs) were within 5.9%. The limits of detection (LODs) were 0.01μg/mL for MPPA, 0.02μg/mL for AMPA, 0.03μg/mL for both glyphosate and glufosinate, and 0.07μg/mL for bialaphos, respectively. PMID:21530973

  12. Simple quantitative determination of potent thiols at ultratrace levels in wine by derivatization and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis.

    PubMed

    Capone, Dimitra L; Ristic, Renata; Pardon, Kevin H; Jeffery, David W

    2015-01-20

    Volatile sulfur compounds contribute characteristic aromas to foods and beverages and are widely studied, because of their impact on sensory properties. Certain thiols are particularly important to the aromas of roasted coffee, cooked meat, passion fruit, grapefruit, and guava. These same thiols enhance the aroma profiles of different wine styles, imparting pleasant aromas reminiscent of citrus and tropical fruits (due to 3-mercaptohexan-1-ol, 3-mercaptohexyl acetate, 4-mercapto-4-methylpentan-2-one), roasted coffee (2-furfurylthiol), and struck flint (benzyl mercaptan), at nanogram-per-liter levels. In contrast to the usual gas chromatography (GC) approaches, a simple and unique high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for routine analysis of five wine thiols, using 4,4'-dithiodipyridine (DTDP) as a derivatizing agent and polydeuterated internal standards for maximum accuracy and precision. DTDP reacted rapidly with thiols at wine pH and provided stable derivatives, which were enriched by solid-phase extraction (SPE) prior to analysis by HPLC-MS/MS. All steps were optimized and the method was validated in different wine matrices, with method performance being comparable to a well-optimized but more cumbersome gas chromatography-mass spectrometry (GC-MS) method. A range of commercial wines was analyzed with the new method, revealing the distribution of the five thiols in white, red, rosé, and sparkling wine styles. PMID:25562625

  13. A rapid determination method for ethylenethiourea in potato and cucumber by modified QuEChERS - high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhou, Li; Liu, Xiaoliang; Kang, Shu; Zhang, Fengzu; Pan, Canping

    2013-06-01

    A rapid and sensitive analytical method for the determination of ethylenethiourea (ETU) in potatoes and cucumbers is developed. This method employs modified QuEChERS followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis. ETU was extracted by alkaline acetonitrile (containing 1%NH(3).H(2)0), separated on a ZIC-pHILIC column, confirmed by multiple reaction monitoring (MRM) mode with electrospray ionisation source. This modified procedure showed satisfactory recovery (90.6-103.5%) fortified at the range of 0.005-0.05 mg kg(-1) with relative standard deviation (RSD)<7%. The limits of detection (LOD) and the limits of quantification (LOQ) were 0.002 mg kg(-1) and 0.005 mg kg(-1), respectively. Matrix effect and HILIC retention mechanism were also evaluated. The method was finally applied to detect ETU in potato and cucumber samples collected at harvest period. Residues of ETU were detected in four cucumber samples with the level lower than LOQ. PMID:23411254

  14. Analysis of selected pharmaceuticals in fish and the fresh water bodies directly affected by reclaimed water using liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Jian; Gardinali, Piero R

    2012-11-01

    A comprehensive method for the analysis of 11 target pharmaceuticals representing multiple commonly used therapeutic classes was developed for biological tissues (fish), reclaimed water, and the surface water directly affected by irrigation with reclaimed water. One gram of fish tissue homogenate was extracted by accelerated solvent extraction with methylene chloride followed by mixed-mode cation exchange solid phase extraction (SPE) cleanup and analyzed by liquid chromatography-tandem mass spectrometry. Compared to previously reported methods, the protocol produces cleaner extracts resulting in lower method detection limits. Similarly, an SPE method based on Oasis HLB cartridges was used to concentrate and cleanup reclaimed and surface water samples. Among the 11 target compounds analyzed, trimethoprim, caffeine, sulfamethoxazole, diphenhydramine, diltiazem, carbamazepine, erythromycin, and fluoxetine were consistently detected in reclaimed water. Caffeine, diphenhydramine, and carbamazepine were consistently detected in fish and surface water samples. Bioaccumulation factors for caffeine, diphenhydramine, and carbamazepine in mosquito fish (Gambusia holbrooki) were calculated at 29 ± 26, 821 ± 422, and 108 ± 144, respectively. This is the first report of potential accumulation of caffeine in fish from a water body directly influenced by reclaimed water. Figure The pharmaceuticals detected in reclaimed water and the fresh water directly affected by reclaimed water. PMID:22678759

  15. Analysis of processing contaminants in edible oils. Part 1. Liquid chromatography-tandem mass spectrometry method for the direct detection of 3-monochloropropanediol monoesters and glycidyl esters.

    PubMed

    MacMahon, Shaun; Mazzola, Eugene; Begley, Timothy H; Diachenko, Gregory W

    2013-05-22

    A new analytical method has been developed and validated for the detection of glycidyl esters (GEs) and 3-monochloropropanediol (3-MCPD) monoesters in edible oils. The target compounds represent two classes of potentially carcinogenic chemical contaminants formed during the processing of edible oils. Target analytes are separated from edible oil matrices using a two-step solid-phase extraction (SPE) procedure. The extracts are then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). Chromatographic conditions that separate sn-1 and sn-2 monoesters of 3-MCPD have been developed for the first time. The method has been validated for GEs, sn-1 3-MCPD monoesters of lauric, myristic, linolenic, linoleic, oleic, and stearic acids, and sn-2 3-MCPD monoesters of oleic and palmitic acids in coconut, olive, and palm oils using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 84-115% (3-16% RSD) for the GEs, 95-113% (1-10% RSD) for the sn-1 3-MCPD monoesters, and 76.8-103% (5.1-11.2% RSD) for the sn-2 3-MCPD monoesters, with limits of quantitation at or below 30 ng/g for the GEs, 60 ng/g for sn-1 3-MCPD monoesters, and 180 ng/g for sn-2 3-MCPD monoesters. PMID:23590632

  16. Analysis of processing contaminants in edible oils. Part 2. Liquid chromatography-tandem mass spectrometry method for the direct detection of 3-monochloropropanediol and 2-monochloropropanediol diesters.

    PubMed

    MacMahon, Shaun; Begley, Timothy H; Diachenko, Gregory W

    2013-05-22

    A method was developed and validated for the detection of fatty acid diesters of 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) in edible oils. These analytes are potentially carcinogenic chemical contaminants formed during edible oil processing. After separation from oil matrices using a two-step solid-phase extraction (SPE) procedure, the target compounds are quantitated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). The first chromatographic conditions have been developed that separate intact diesters of 2-MCPD and 3-MCPD, allowing for their individual quantitation. The method has been validated for 28 3-MCPD diesters of lauric, myristic, palmitic, linolenic, linoleic, oleic, and stearic acids in coconut, olive, and palm oils, as well as 3 2-MCPD diesters, using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 88-118% (2-16% RSD) with maximum limits of quantitation of 30 ng/g (ppb). PMID:23590587

  17. Molecularly imprinted solid-phase extraction for the determination of ten macrolide drugs residues in animal muscles by liquid chromatography-tandem mass spectrometry.

    PubMed

    Song, Xuqin; Zhou, Tong; Liu, Qingying; Zhang, Meiyu; Meng, Chenying; Li, Jiufeng; He, Limin

    2016-10-01

    A simple and sensitive method based on molecularly imprinted solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry was developed for the determination of the residues of ten macrolide drugs in swine, cattle and chicken muscles samples. The molecularly imprinted polymers (MIPs) were synthesized using tylosin as a template and methacrylic acid as a functional monomer. Samples were extracted with sodium borate buffer solution and ethyl acetate, and purified by the MIP cartridge. The results showed that the cartridge exhibited good recognition performance for macrolides, and better purification effect than the traditional solid-phase extraction cartridges. Recoveries of analytes at three spiking levels 1, 5 and 20μgkg(-1) ranged from 60.7% to 100.3% with the relative standard deviations less than 14%. The limits of detection of the method were between 0.1 and 0.4μgkg(-1). The method is useful for the routine monitoring of the residues of macrolide drugs in animal muscles. PMID:27132837

  18. The use of 18O-exchange and base-catalyzed N-dealkylation with liquid chromatography/tandem mass spectrometry to identify carbinolamide metabolites.

    PubMed

    Bessire, Andrew J; Vaz, Alfin D N; Walker, Gregory S; Wang, Wei Wei; Sharma, Raman

    2010-07-30

    Oxidation of N-alkyl-substituted amides is a common transformation observed in metabolism studies of drugs and other chemicals. Metabolism at the alpha carbon atom can produce stable carbinolamide compounds, which may be abundant enough to require complete confidence in structural assignments. In a drug discovery setting, rapid structural elucidation of test compounds is critical to inform the compound selection process. Traditional approaches to the analysis of carbinolamides have relied upon the time-consuming synthesis of authentic standards or purification of large enough quantities for characterization by nuclear magnetic resonance (NMR). We describe a simple technique used in conjunction with liquid chromatography/tandem mass spectrometry (LC/MS/MS) which demonstrates the chemical identity of a carbinolamide by its distinctive ability to reversibly exchange [(18)O]water through an imine intermediate. A key advantage of the technique is that the chromatographic retention times of metabolites are preserved, allowing direct comparisons of mass chromatograms from non-treated and [(18)O]water-treated samples. Metabolites susceptible to the treatment are clearly indicated by the addition of 2 mass units to their original mass. An additional test which can be used in conjunction with (18)O-exchange is base-catalyzed N-dealkylation of N-(alpha-hydroxy)alkyl compounds. The use of the technique is described for carbinolamide metabolites of dirlotapide, loperamide, and a proprietary compound. PMID:20552706

  19. In vitro assay of six UDP-glucuronosyltransferase isoforms in human liver microsomes, using cocktails of probe substrates and liquid chromatography-tandem mass spectrometry.

    PubMed

    Seo, Kyung-Ah; Kim, Hyo-Ji; Jeong, Eun Sook; Abdalla, Nagi; Choi, Chang-Soo; Kim, Dong-Hyun; Shin, Jae-Gook

    2014-11-01

    UDP-glucuronosyltransferase (UGT)-mediated drug-drug interactions are commonly evaluated during drug development. We present a validated method for the simultaneous evaluation of drug-mediated inhibition of six major UGT isoforms, developed in human liver microsomes through the use of pooled specific UGT probe substrates (cocktail assay) and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The six probe substrates used in this assay were estradiol (UGT1A1), chenodeoxycholic acid (UGT1A3), trifluoperazine (UGT1A4), 4-hydroxyindole (UGT1A6), propofol (UGT1A9), and naloxone (UGT2B7). In a cocktail incubation, UGT1A1, UGT1A9, and UGT2B7 activities were substantially inhibited by other substrates. This interference could be eliminated by dividing substrates into two incubations: one containing estradiol, trifluoperazine, and 4-hydroxyindole, and the other containing chenodeoxycholic acid, propofol, and naloxone. Incubation mixtures were pooled for the simultaneous analysis of glucuronyl conjugates in a single LC-MS/MS run. The optimized cocktail method was further validated against single-probe substrate assays using compounds known to inhibit UGTs. The degree of inhibition of UGT isoform activities by such known inhibitors in this cocktail assay was not substantially different from that in single-probe assays. This six-isoform cocktail assay may be very useful in assessing the UGT-based drug-interaction potential of candidates in a drug-discovery setting. PMID:25122565

  20. A simple and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method to determine plasma biotin in hemodialysis patients.

    PubMed

    Yagi, Shigeaki; Nishizawa, Manabu; Ando, Itiro; Oguma, Shiro; Sato, Emiko; Imai, Yutaka; Fujiwara, Masako

    2016-08-01

    A simple, rapid, and selective method for determination of plasma biotin was developed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After single-step protein precipitation with methanol, biotin and stable isotope-labeled biotin as an internal standard (IS) were chromatographed on a pentafluorophenyl stationary-phase column (2.1 × 100 mm, 2.7 μm) under isocratic conditions using 10 mm ammonium formate-acetonitrile (93:7, v/v) at a flow rate of 0.6 mL/min. The total chromatographic runtime was 5 min for each injection. Detection was performed in a positive electrospray ionization mode by monitoring selected ion transitions at m/z 245.1/227.0 and 249.1/231.0 for biotin and the IS, respectively. The calibration curve was linear in the range of 0.05-2 ng/mL using 300 μL of plasma. The intra- and inter-day precisions were all <7.1%. The accuracy varied from -0.7 to 8.2%. The developed UHPLC-MS/MS method was successfully applied to determine plasma biotin concentrations in hemodialysis patients. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26715368

  1. Rapid determination of trans-resveratrol in vegetable oils using magnetic hydrophilic multi-walled carbon nanotubes as adsorbents followed by liquid chromatography-tandem mass spectrometry.

    PubMed

    Ma, Fei; Li, Peiwu; Zhang, Qi; Yu, Li; Zhang, Liangxiao

    2015-07-01

    In the present work, a rapid and simple procedure was developed and validated for the analysis of trans-resveratrol in vegetable oils based on magnetic hydrophilic multi-walled carbon nanotubes (h-MWCNT-MNPs) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). h-MWCNT-MNPs were simply obtained by wrapping amine-functionalized Fe3O4 magnetic nanoparticles into previously oxidized hydrophilic multi-walled carbon nanotubes. The major parameters affecting extraction efficiency were investigated, including the type and volume of desorption solvents, extraction and desorption time, washing solution, and sorbent amount. The limit of detection (LOD) and the limit of quantification (LOQ) were calculated as 0.6 and 2.0 μg/kg, respectively. The recoveries of trans-resveratrol in oil samples were in the range of 90.0-110.0% with RSDs of less than 17.5%. The results showed that only peanut oil contained trans-resveratrol, ranging from 8 ± 1 to 103 ± 12 μg/kg. The proposed method is reliable and robust, having an excellent potential for the analysis of trans-resveratrol in edible oils. PMID:25704710

  2. Rapid analysis of biogenic amines from rice wine with isotope-coded derivatization followed by high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Yiping; Sun, Zhiwei; Chen, Guang; Liu, Xiaomei; You, Jinmao; Zhang, Caiqing

    2016-02-01

    A pair of isotope-coded derivatization reagents, d0-10-methyl-acridone-2-sulfonyl chloride (d0-MASC, light form) and d3-10-methyl-acridone-2-sulfonyl chloride (d3-MASC, heavy form), were used for labeling biogenic amines (BAs). On basis of the isotope-coded derivatization, a global isotope internal standard quantitative method for determining seven BAs by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The d0-MASC and d3-MASC can easily label BAs under mild conditions within 15 min at 50 °C. The obtained light and heavy labeled BAs were monitored by the transitions of [M+H](+) → 208 and [M+H](+) → 211, respectively. Relative quantification of BAs was achieved by calculation of the peak area ratios of d0-MASC/d3-MASC labeled derivatives. Excellent linear responses for relative quantification were observed in the range of 1/10-10/1. The developed method has been successfully applied to the quantification of BAs in Chinese rice wine with recoveries ranging from 94.9% to 104.5%. PMID:26304364

  3. Fast determination of 24 steroid hormones in river water using magnetic dispersive solid phase extraction followed by liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhao, Yong-Gang; Zhang, Yun; Zhan, Ping-Ping; Chen, Xiao-Hong; Pan, Sheng-Dong; Jin, Mi-Cong

    2016-01-01

    The easiness-to-handle of the magnetic dispersive solid phase extraction (Mag-dSPE) procedure was developed for preconcentration of 24 steroid hormones in river water. Ethylenediamine-functionalized magnetic carbon nanotubes (EDA@Mag-CNTs) were synthesised by a simple one-pot reaction and were used as sorbent in Mag-dSPE procedure. The properties of the EDA@Mag-CNTs were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). An ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) method for determination of 24 steroid hormones in river water at nanograms per liter had been developed with pretreatment of the samples by Mag-dSPE. The obtained results demonstrated the higher extraction capacity of EDA@Mag-CNT Mag-dSPE with recoveries between 82.1 and 113%. The limits of quantification (LOQs) for the steroid hormone were between 0.020 and 1.00 ng/L. The developed method had been successfully applied to 60 river water samples, and it was confirmed that EDA@Mag-CNT Mag-dSPE was a highly effective extraction method for the steroid hormone analyses. PMID:26377965

  4. Determination of Geochemically Important Sterols and Triterpenols in Sediments Using Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry (UHPLC-MS/MS).

    PubMed

    Bataglion, Giovana Anceski; Meurer, Eduardo; de Albergaria-Barbosa, Ana Cecília Rizzatti; Bícego, Márcia Caruso; Weber, Rolf Roland; Eberlin, Marcos Nogueira

    2015-08-01

    A fast, sensitive, and selective ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method that is able to quantify geochemical biomarkers in sediment is described. A pool of 10 sterols, which can be used as biomarkers of autochthonous (cholesterol, cholestanol, brassicasterol, ergosterol), allochthonous (stigmasterol, β-sitosterol, campesterol, and stigmastanol) and anthropogenic (coprostanol and epicoprostanol) organic matter (OM), and three triterpenols (lupeol, α-amyrin, and β-amyrin) were chosen as the analytes. The method showed excellent analytical parameters, and, compared with the traditional GC-MS methods that are commonly applied for the analysis of sterols, this method requires no sample cleanup or derivatization and presents improved values for the LOD and LOQ. UHPLC can separate the diastereoisomers (epicoprostanol, coprostanol, and cholestanol) and the isomers (lupeol, α-amyrin, and β-amyrin). The method was successfully applied for the quantification of the biomarkers, and thus, it was applied to assess the OM sources and the impacts of anthropogenic activities in sediments from different environments, such as Antarctica and other Brazilian systems (Continental Shelf, São Sebastião Channel, and Santos Estuary). Unique profiles of the biomarkers were observed for the contrasting environments, and β-amyrin and cholesterol were more predominant in the Santos Estuary and Antarctica samples, respectively. The sterol ratios indicated a higher level of sewage contamination in the Santos Estuary. PMID:26132310

  5. Simultaneous determination of pradefovir, PMEA and tenofovir in HBV patient serum using liquid chromatography-tandem mass spectrometry and application to phase 2 clinical trial.

    PubMed

    Xiao, Qingqing; Wang, Dan; Yang, Wanqiu; Chen, Lin; Ding, Yitao; Yang, Jin

    2016-06-01

    Pradefovir, a prodrug of PMEA, is under phase 2 clinical trial in China to evaluate its pharmacokinetic and pharmacodynamics after multiple-dose study, with adefovir dipivoxil and tenofovir disoproxil fumarate as positive control. A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of pradefovir, PMEA and tenofovir in HBV patient serum. Serum samples were pretreated via simple protein precipitation with methanol and entecavir was used as internal standard. Chromatographic separation was carried out on a Synergi(®) fusion-RP column (150mm×4.6mm) by gradient elution with methanol and 0.1% formic acid in water (v/v) at a flow rate of 1mL/min. The analytes were detected in multiple reaction monitoring mode with positive ion electrospray ionization at m/z 424.1/151.0, 274.1/162.2, 288.1/176.1, and 278.1/152.2for pradefovir, PMEA, tenofovir and IS, respectively. The assays were validated according to current bioanalytical guidelines including specificity, linearity (2.0-500ng/mL for pradefovir and PMEA, 4.0-1000ng/mL for tenofovir), accuracy and precision, extraction recovery, matrix effect and stability. The validated method has been successfully applied to the pharmacokinetic study of pradefovir, adefovir dipivoxil and tenofovir disoproxil fumarate in a set of HBV patients. PMID:27089519

  6. Dispersive solid-phase extraction followed by liquid chromatography-tandem mass spectrometry for the multi-residue analysis of pesticides in raw bovine milk.

    PubMed

    Dagnac, Thierry; Garcia-Chao, Maria; Pulleiro, Paula; Garcia-Jares, Carmen; Llompart, Maria

    2009-05-01

    A fast multi-residue method based on dispersive solid-phase extraction (DSPE) followed by liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 44 pesticides in raw bovine milk. Raw bovine milk samples did not percolate through SPE cartridges usually applied for pesticide extraction from homogenized pasteurized milk samples. Therefore, a DSPE technique was implemented and validated for the first time in this work. Graphitized non-porous carbon and C18 modified silica materials were tested both in combination with magnesium sulfate and bonded silica with ethylenediamine-N-propyl phase. The efficiency of the DSPE process was studied at several concentration levels obtaining the higher recoveries with C18 material. The method performance was also assessed and the limits of quantification reached the ng g(-1) level, complying with the most recent maximum residue levels. The DSPE method was also shown to be suited to both the fatty and skimmed fractions issued from raw milk. Finally, the extraction method was successfully applied to the analysis of raw milk samples collected in 23 farms of dairy cattle from NW Spain (Galicia). PMID:19268955

  7. Residue analysis and degradation studies of fenbuconazole and myclobutanil in strawberry by chiral high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Hu; Wang, Xinquan; Qian, Mingrong; Wang, Xiangyun; Xu, Hao; Xu, Mingfei; Wang, Qiang

    2011-11-23

    A simple and sensitive enantioselective method for the determination of fenbuconazole and myclobutanil in strawberry was developed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Fenbuconazole and myclobutanil residues in strawberry were extracted with acetonitrile containing 1% acetic acid, and an aliquot was cleaned up with PSA (primary and secondary amine) and C(18) sorbent. The direct resolution of fenbuconazole and myclobutanil enantiomers was performed on a cellulose tris (3,5-dimethylphenylcarbamate) column using acetonitrile-0.1% formic acid solution (60:40, v/v) as the mobile phase. Quantification was achieved using matrix-matched standard calibration curves, and the limits of quantification for fenbuconazole and myclobutanil enantiomers in strawberry were both 2 μg/kg. The method was successfully utilized to investigate the probable enantioselective degradation of fenbuconazole and myclobutanil in strawberry. The results showed that the degradation of the fenbuconazole and myclobutanil enantiomers in strawberry followed pseudofirst-order kinetics (R(2) > 0.97). The results from this study revealed that the degradation of fenbuconazole in strawberry was not enantioselective, while the degradation of myclobutanil was enantioselective, and the (+)-myclobutanil showed a faster degradation than (-)-myclobutanil in strawberry, resulting in the relative enrichment of (-)-myclobutanil in residue. The results could provide a reference to fully evaluate the risks of these two fungicides. PMID:21967215

  8. Multi-target determination of organic ultraviolet absorbents in organism tissues by ultrasonic assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Peng, Xianzhi; Jin, Jiabin; Wang, Chunwei; Ou, Weihui; Tang, Caiming

    2015-03-01

    A sensitive and reliable method was developed for multi-target determination of 13 most widely used organic ultraviolet (UV) absorbents (including UV filters and UV stabilizers) in aquatic organism tissues. The organic UV absorbents were extracted using ultrasonic-assisted extraction, purified via gel permeation chromatography coupled with silica gel column chromatography, and determined by ultra-high performance liquid chromatography-tandem mass spectrometry. Recoveries of the UV absorbents from organism tissues mostly ranged from 70% to 120% from fish filet with satisfactory reproducibility. Method quantification limits were 0.003-1.0ngg(-1) dry weight (dw) except for 2-ethylhexyl 4-methoxycinnamate. This method has been applied to analysis of the UV absorbents in wild and farmed aquatic organisms collected from the Pearl River Estuary, South China. 2-Hydroxy-4-methoxybenzophenone and UV-P were frequently detected in both wild and farmed marine organisms at low ngg(-1)dw. 3-(4-Methylbenzylidene)camphor and most of the benzotriazole UV stabilizers were also frequently detected in maricultured fish. Octocrylene and 2-ethylhexyl 4-methoxycinnamate were not detected in any sample. This work lays basis for in-depth study about bioaccumulation and biomagnification of the UV absorbents in marine environment. PMID:25637008

  9. Determination of the novel antiarrhythmic drug sulcardine sulfate in human plasma by liquid chromatography tandem mass spectrometry and its application in a clinical pharmacokinetic study.

    PubMed

    Jia, Jingying; Liu, Gangyi; Zhang, Mengqi; Lu, Youli; Lu, Chuan; Liu, Yun; Zheng, Hongcao; Wang, Wei; Gui, Yuzhou; Yu, Chen; Li, Shuijun; Wang, Yiping

    2016-08-01

    Sulcardine sulfate (Sul), a novel antiarrhythmic agent, is currently in phase I and phase II clinical trials. To elucidate its clinical pharmacokinetic characteristics, a rapid and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantification of Sul in human plasma. Plasma samples were precipitated by acetonitrile and isotope-labeled sulcardine was added as internal standard. The analysis was carried out on a Capcell Pak C18 MG III column (100 × 2.0 mm, 5 μm) with 0.1% formic acid in acetonitrile solution and water (17:83, v/v) as mobile phase. The linear range was 5.0-1000 ng/mL for Sul, with a lower limit of quantification of 5.0 ng/mL. The intra- and inter-batch CVs were within ±11.0% and the accuracies were 4.9-107.3%. Our method, for the first time, allows the rapid (only 3.0 min) and accurate quantification of Sul in human plasma. The method has been successfully applied in the pharmacokinetic study of Sul in a clinical trial following oral administration of Sul to healthy volunteers. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26715470

  10. Analysis of polyols in urine by liquid chromatography-tandem mass spectrometry: a useful tool for recognition of inborn errors affecting polyol metabolism.

    PubMed

    Wamelink, M M C; Smith, D E C; Jakobs, C; Verhoeven, N M

    2005-01-01

    Several inborn errors of metabolism with abnormal polyol concentrations in body fluids are known to date. Most of these defects can be diagnosed by the assessment of urinary concentrations of polyols. We present two methods using tandem mass spectrometry for screening for inborn errors affecting polyol metabolism. Urine samples supplemented with internal standards ([13C4]erythritol, [13C2]arabitol and [2H3]sorbitol) were desalted by a mixed-bed ion-exchange resin. Separation was achieved by two different columns. Sugar isomers could not be separated using a Prevail Carbohydrate ES 54 column (method 1), whereas with the other column (Aminex HPX-87C) separation of the isomers was achieved (method 2). Multiple reaction monitoring polyol detection was achieved by tandem mass spectrometry with an electron ion-spray source operating in the negative mode. Age-related reference ranges of polyols (erythritol, treitol, arabitol, ribitol, xylitol, galactitol, mannitol, sorbitol, sedoheptitol and perseitol) in urine were established. The applicability of the method was demonstrated by the abnormal polyol concentrations observed in patients with transaldolase deficiency, ribose-5-phosphate isomerase deficiency and classical galactosaemia. This paper describes two methods for the analysis of urinary polyols by liquid chromatography-tandem mass spectrometry. Method 1 is a fast screening method with the quantification of total isomers and method 2 is a more selective method with the separate quantification of the polyols. Both methods can be used for diagnosing inborn errors of metabolism affecting polyol metabolism. PMID:16435188

  11. Determination of secondary and tertiary amines as N-nitrosamine precursors in drinking water system using ultra-fast liquid chromatography-tandem mass spectrometry.

    PubMed

    Wu, Qihua; Shi, Honglan; Ma, Yinfa; Adams, Craig; Eichholz, Todd; Timmons, Terry; Jiang, Hua

    2015-01-01

    N-Nitrosamines are potent mutagenic and carcinogenic emerging water disinfection by-products (DBPs). The most effective strategy to control the formation of these DBPs is minimizing their precursors from source water. Secondary and tertiary amines are dominating precursors of N-nitrosamines formation during drinking water disinfection process. Therefore, the screening and removal of these amines in source water are very essential for preventing the formation of N-nitrosamines. A rapid, simple, and sensitive ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed in this study to determine seven amines, including dimethylamine, ethylmethylamine, diethylamine, dipropylamine, trimethylamine, 3-(dimethylaminomethyl)indole, and 4-dimethylaminoantipyrine, as major precursors of N-nitrosamines in drinking water system. No sample preparation process is needed except a simple filtration. Separation and detection can be achieved in 11 min per sample. The method detection limits of selected amines are ranging from 0.02 μg/L to 1 μg/L except EMA (5 μg/L), and good calibration linearity was achieved. The developed method was applied to determine the selected precursors in source water and drinking water samples collected from Midwest area of the United States. In most of water samples, the concentrations of selected precursors of N-nitrosamines were below their method detection limits. Dimethylamine was detected in some of water samples at the concentration up to 25.4 μg/L. PMID:25281166

  12. Assay for methylmalonyl coenzyme A mutase activity based on determination of succinyl coenzyme A by ultrahigh-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Gotoh, Kana; Nakajima, Yoko; Tajima, Go; Hotta, Yuji; Kataoka, Tomoya; Kawade, Yoshihiro; Sugiyama, Naruji; Ito, Tetsuya; Kimura, Kazunori; Maeda, Yasuhiro

    2015-07-01

    Methylmalonic acidemia (MMA) is an inherited metabolic disease. In this condition, metabolism from methylmalonyl coenzyme A (CoA) to succinyl-CoA is inhibited because of either low methylmalonyl-CoA mutase (MCM) activity or adenosylcobalamin deficiency owing to altered vitamin B12 metabolism. A high-precision assay for detecting MCM activity would facilitate not only MMA diagnosis but also the ability to determine the severity of MMA. We developed an MCM assay method based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) that involves the determination of succinyl-CoA, which is formed in an enzyme reaction, using peripheral lymphocytes. Using 0.05, 0.5, and 5 μmol/L succinyl-CoA, the intra-assay coefficient of variation (CV) was less than 5.2% and the inter-assay CV was less than 8.7%. The MCM activities of five healthy individuals and four patients were investigated with this assay. The MCM activities of the patients were very low in relation to those of healthy individuals. Together, these results show that the UPLC-MS/MS method is useful for a detailed MCM activity assay. PMID:26018627

  13. Determination of six polyether antibiotic residues in foods of animal origin by solid phase extraction combined with liquid chromatography-tandem mass spectrometry.

    PubMed

    Ha, Jing; Song, Ge; Ai, Lian-feng; Li, Jian-Chen

    2016-04-01

    A new method using solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of six polyether antibiotics, including lasalocid, salinomycin, monensin, narasin, madubamycin and nigericin residues, in foods of animal origin. The samples were extracted with acetonitrile and purified by ENVI-Carb SPE columns after comparing the impurity effect and maneuverability of several SPE cartridges. Subsequently, the analytes were separated on a Hypersil Gold column (2.1×150mm, 5μm) and analyzed by MS/MS detection. The limit of quantization (LOQ) for milk and chicken was 0.4μg/kg, and for chicken livers and eggs, it was 1μg/kg. The linearity was satisfactory with a correlation coefficient of >0.9995 at concentrations ranging from 2 to 100μg/L. The average recoveries of the analytes fortified at three levels ranged from 68.2 to 114.3%, and the relative standard deviations ranged from 4.5 to 12.1%. The method was suitable for quantitative analysis and confirmation of polyether antibiotic residues in foods of animal origin. PMID:26990733

  14. Rapid detection of multiple class pharmaceuticals in both municipal wastewater and sludge with ultra high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Yuan, Xiangjuan; Qiang, Zhimin; Ben, Weiwei; Zhu, Bing; Liu, Junxin

    2014-09-01

    This work described the development, optimization and validation of an analytical method for rapid detection of multiple-class pharmaceuticals in both municipal wastewater and sludge samples based on ultrasonic solvent extraction, solid-phase extraction, and ultra high performance liquid chromatography-tandem mass spectrometry quantification. The results indicated that the developed method could effectively extract all the target pharmaceuticals (25) in a single process and analyze them within 24min. The recoveries of the target pharmaceuticals were in the range of 69%-131% for wastewater and 54%-130% for sludge at different spiked concentration levels. The method quantification limits in wastewater and sludge ranged from 0.02 to 0.73ng/L and from 0.02 to 1.00μg/kg, respectively. Subsequently, this method was validated and applied for residual pharmaceutical analysis in a wastewater treatment plant located in Beijing, China. All the target pharmaceuticals were detected in the influent samples with concentrations varying from 0.09ng/L (tiamulin) to 15.24μg/L (caffeine); meanwhile, up to 23 pharmaceuticals were detected in sludge samples with concentrations varying from 60ng/kg (sulfamethizole) to 8.55mg/kg (ofloxacin). The developed method demonstrated its selectivity, sensitivity, and reliability for detecting multiple-class pharmaceuticals in complex matrices such as municipal wastewater and sludge. PMID:25193847

  15. Rapid determination of 12 antibiotics and caffeine in sewage and bioreactor effluent by online column-switching liquid chromatography/tandem mass spectrometry.

    PubMed

    Lima Gomes, Paulo C F; Tomita, Inês N; Santos-Neto, Álvaro J; Zaiat, Marcelo

    2015-11-01

    This study presents a column-switching solid-phase extraction online-coupled to a liquid chromatography/tandem mass spectrometry (SPE-LC-MS/MS) method for simultaneous analysis of 12 antibiotics (7 sulfonamides and 5 fluoroquinolones) and caffeine detected in the sewage and effluent of a pilot anaerobic reactor used in sewage treatment. After acidification and filtration, the samples were directly injected into a simple and conventional LC system. Backflush and foreflush modes were compared based on the theoretical plates and peak asymmetry observed. The method was tested in terms of detection (MDL) and quantification limit (MQL), linearity, relative recovery, and precision intra- and inter-day in lab-made sewage samples. The method presented suitable figures of merit in terms of detection, varying from 8.00 × 10(-5) to 6.00 × 10(-2) ng (0.800 up to 600 ng L(-1); caffeine) with direct injection volume of only 100 μL and 13 min of total analysis time (sample preparation and chromatographic run). When the method was applied in the analysis of sewage and effluent of the anaerobic reactor (n = 15), six antibiotics and caffeine were detected in concentrations ranging from 0.018 to 1097 μg L(-1). To guarantee a reliable quantification, standard addition was used to overcome the matrix effect. PMID:26446896

  16. Pharmacokinetic study of 14-(3-methylbenzyl)matrine and 14-(4-methylbenzyl)matrine in rat plasma using liquid chromatography-tandem mass spectrometry.

    PubMed

    Jiang, Minjie; Wang, Lisheng; Huang, Shulin; Xu, Liba; Hu, Chao; Jiang, Weizhe

    2015-01-01

    A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS) was developed and validated to determine the 14-(3-methylbenzyl)matrine (3MBM) and 14-(4-methylbenzyl)matrine (4MBM) levels in rat plasma in the present study. The analytes were separated using a C18 column (1.9 μm, 2.1 mm × 100 mm) equipped with a Security Guard C18 column (5 μm, 2.1 mm × 10 mm), followed by detection via triple-quadrupole mass spectrometry using an electrospray ionization (ESI) source. Sample pretreatment involved one-step protein precipitation with isopropanol:ethyl acetate (v/v, 25:75), and pseudoephedrine hydrochloride was used as an internal standard. The method was linear in the concentration range of 5-2000 ng/ml for both compounds. The intra-day and inter-day relative standard deviations (RSDs) were less than 15%, and all relative errors (REs) were within 15%. The proposed method enables the unambiguous identification and quantification of these two compounds in vivo. This study is the first to determine the 3MBM and 4MBM levels in rat plasma after oral administration of these compounds. These results provide a meaningful basis for evaluating the clinical applications of these medicines. PMID:25714369

  17. Porous membrane-protected molecularly imprinted polymer micro-solid-phase extraction for analysis of urinary cocaine and its metabolites using liquid chromatography - Tandem mass spectrometry.

    PubMed

    Sánchez-González, Juan; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2015-10-22

    Porous membrane-protected micro-solid phase extraction (μ-SPE) using a molecularly imprinted polymer (MIP) as an adsorbent has been proposed as an integrated extraction-cleanup procedure for isolating cocaine (COC) and its metabolites [benzoylecgonine (BZE), ecgonine methyl ester (EME), and cocaethylene (CE)] from human urine. MIP beads have been synthesized using COC as a template molecule, ethylene dimethacrylate (EDMA) as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. High performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) has been used for quantifying the analytes after MIP-μ-SPE. Variables such as urine pH, adsorption temperature and time, mechanical (orbital-horizontal) stirring; and composition of the eluting solution and eluting time, were evaluated. The proposed method was shown to be precise and accurate [relative standard deviations (RSDs) of intra- and inter-day tests ranging from 3 to 8% and from 2 to 10%, respectively]; and analytical recoveries in the range of 89-100%). In addition, excellent accuracy was also verified after analyzing a FDT +25% control material for BZE. The detection limits were in the range of 0.16-1.7 ng L(-1), low enough for confirmative conclusions regarding cocaine abuse. The method was finally applied for screening/quantifying cocaine and metabolites in urine samples from poly-drug abusers. PMID:26526910

  18. Simultaneous determination of nineteen major components in Qi She Pill by ultra-high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Zhongliang; Li, Qiang; Li, Qiufen; Du, Simiao; Zhou, Yongquan; Lv, Chunming; Zhao, Yan; Wang, Yongjun; Zhang, Ning

    2014-10-01

    Qi She Pill (QSP) is a traditional Chinese medicine (TCM) prescription that has been used in treating cervical spondylosis radiculopathy for many years. In this study, a simple and sensitive method using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) on a reverse-phase C18 column was developed for the simultaneous determination of the 19 major components in QSP. We found that the optimum mobile phase for gradient elution was 0.1% formic acid and methanol. The correlation coefficients of all calibration curves were greater than 0.99. Recoveries measured at three concentration levels varied from 95.43% to 102.35%. Relative standard deviations of intra- and inter-day precisions were less than 4.45%. After successfully validating our method, we then applied it to the quantification of 19 components in QSP products to show that this method provides a new standard in quality assessment of TCM prescriptions containing multiple bioactive components. PMID:26579408

  19. Development, validation of liquid chromatography-tandem mass spectrometry method for simultaneous determination of rosuvastatin and metformin in human plasma and its application to a pharmacokinetic study

    PubMed Central

    Kumar, P. Pavan; Murthy, T. E. G. K.; Basaveswara Rao, M. V.

    2015-01-01

    A new, simple and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of rosuvastatin (ROS) and metformin (MET) in human plasma was developed. The assay procedure involved simple protein precipitation with acetonitrile. Following precipitation, fraction of supernatant was decanted and evaporated under gentle stream of nitrogen at 40°C. The residue was reconstituted in mobile phase and injected. The chromatographic separation was achieved with Thermo Hypurity C18 column (50 mm × 4.6 mm, 5 μ) using a mobile phase composition containing 0.1% v/v formic acid in water and acetonitrile (30:70, v/v) at a flow rate of 0.4 mL/min. The total run time was 3.5 min. The method showed good linearity in the range 0.5–200 ng/mL for ROS and 2–2000 ng/mL for MET with correlation coefficient (r) >0.9994 for both the analytes. The intra and inter-day precision values for ROS and MET met the acceptance criteria as per regulatory guidelines. The battery of stability studies viz., bench-top, freeze-thaw and long term stability were performed. The developed method was applied to a pharmacokinetic study. PMID:26317076

  20. Rapid and sensitive method for the determination of sibutramine active metabolites in human plasma by reversed-phase liquid chromatography-tandem mass spectroscopy.

    PubMed

    Bhatt, Jignesh; Shah, Bhavin; Kambli, Sandeep; Subbaiah, Gunta; Singh, Sadhana; Ameta, Suresh

    2007-02-01

    A new, rapid, and sensitive liquid chromatography-tandem mass spectrometry method is developed and validated to quantitate the sibutramine active metabolites mono desmethyl sibutramine (M1) and di-desmethyl sibutramine (M2) using imipramine as the internal standard in human plasma samples for routine bioequivalence studies. The method involves rapid solid-phase extraction from plasma, eliminating the drying and reconstitution steps. The analytes are chromatographed on a C8 reversed-phase chromatographic column and analyzed by mass spectrometry in the multiple reaction monitoring mode, which enables a quantitation limit at the sub-nanogram level. The method has a chromatographic run time of 2.8 min. The proposed method is validated with a linear range of 0.1-8.0 and 0.2-16.0 ng/mL for M1 and M2, respectively, with a correlation coefficient of regression > or = 0.9990. The method is sensitive and reproducible, having intra- and inter-assay precision at the lower limit of quantitation (0.1 ng/mL for M1 and 0.2 ng/mL for M2) < 10.0%. The overall recovery for M1 and M2 is 93.5% and 77.9%, respectively. The method has been applied to a bioequivalence clinical study with great success. PMID:17425138

  1. Simultaneous determination of 11 β-agonists in human urine using high-performance liquid chromatography/tandem mass spectrometry with isotope dilution.

    PubMed

    Wang, Xiaoli; Guo, Tao; Wang, Shanshan; Yuan, Jinpeng; Zhao, Rusong

    2015-04-01

    The misuse of β-agonists constitutes a potential risk to public health and has been forbidden in many countries. In this study, we describe a method for specific, sensitive and rapid detection of β-agonists in human urine. Urine samples were extracted with ethyl acetate, without any additional purification step, and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) with Clenbuterol-D9 and Salbuterol-D3 as internal standards. The intra- and interday precision values of the method were all <5.60% and the accuracy ranged from 94.5 to 109%. Extraction recovery for 11 β-agonists varied from 66.7 to 108%. One UPLC-MS-MS analysis could be completed within 12 min and the limits of detection for 11 β-agonists were 0.1 ng/mL in the experiment. β-Agonists in human urines from 24 volunteers were analyzed by our validated method and 1.70 ng/mL salbutamol was detected in one volunteer. The application of UPLC-MS-MS method in β-agonists detection of human urine will be helpful in veterinary control of β-agonists and for studying the effect of β-agonists on human health. PMID:25542892

  2. Determination of neonicotinoid pesticides residues in agricultural samples by solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    PubMed

    Xie, Wen; Han, Chao; Qian, Yan; Ding, Huiying; Chen, Xiaomei; Xi, Junyang

    2011-07-15

    This work reports a new sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, confirmation and quantification of six neonicotinoid pesticides (dinotefuran, thiamethoxam, clothiandin, imidacloprid, acetamiprid and thiacloprid) in agricultural samples (chestnut, shallot, ginger and tea). Activated carbon and HLB solid-phase extraction cartridges were used for cleaning up the extracts. Analysis is performed by LC-MS/MS operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Quantification was carried by the internal standard method with D(4)-labeled imidacloprid. The method showed excellent linearity (R(2)≥0.9991) and precision (relative standard deviation, RSD≤8.6%) for all compounds. Limits of quantification (LOQs) were 0.01 mg kg(-1) for chestnut, shallot, ginger sample and 0.02 mg kg(-1) for tea sample. The average recoveries, measured at three concentrations levels (0.01 mg kg(-1), 0.02 mg kg(-1) and 0.1 mg kg(-1) for chestnut, shallot, ginger sample, 0.02 mg kg(-1), 0.04 mg kg(-1) and 0.2 mg kg(-1) for tea sample), were in the range 82.1-108.5%. The method was satisfactorily validated for the analysis of 150 agricultural samples (chestnut, shallot, ginger and tea). Imidacloprid and acetamiprid were detected at concentration levels ranging from 0.05 to 3.6 mg kg(-1). PMID:21641601

  3. Investigating the chemical nature of humic-like substances (HULIS) in North American atmospheric aerosols by liquid chromatography tandem mass spectrometry

    NASA Astrophysics Data System (ADS)

    Stone, Elizabeth A.; Hedman, Curtis J.; Sheesley, Rebecca J.; Shafer, Martin M.; Schauer, James J.

    The high-molecular weight water-soluble organic compounds present in atmospheric aerosols underwent functional-group characterization using liquid chromatography tandem mass spectrometry (LC-MS/MS), with a focus on understanding the chemical structure and origins of humic-like substances (HULIS) in the atmosphere. Aerosol samples were obtained from several locations in North America at times when primary sources contributing to organic aerosol were well-characterized: Riverside, CA, Fresno, CA, urban and peripheral Mexico City, Atlanta, GA, and Bondville, IL. Chemical analysis targeted identification and quantification of functional groups, such as aliphatic, aromatic, and bulk carboxylic acids, organosulfates, and carbohydrate-like substances that comprise species with molecular weights (MW) 200-600 amu. Measured high-MW functional groups were compared to modeled primary sources with the purpose of identifying associations between aerosol sources, high-MW aerosol species, and HULIS. Mobile source emissions were linked to high-molecular weight carboxylic acids, especially aromatic acids, biomass burning was associated with carboxylic acids and carbohydrate-like substances, and secondary organic aerosol (SOA) correlated well with the total amount of HULIS measured, whereas organosulfates showed no correlation with aerosol sources and exhibited unique spatial trends. These results suggested the importance of motor vehicles, biomass burning, and SOA as important sources of precursors to HULIS. Structural characteristics of atmospheric HULIS were compared to terrestrial humic and fulvic acids and revealed striking similarities in chemical structure, with the exception of organosulfates which were unique to atmospheric HULIS.

  4. [Determination of 135 pesticides and their metabolites in Angelica sinensis by ultra-fast liquid chromatography-tandem mass spectrometry coupled with solid-phase extraction].

    PubMed

    Liu, Jie; Tong, Ling; Meng, Wenting; Zhao, Yunli; Yu, Zhiguo

    2015-12-01

    A method using solid-phase extraction (SPE) followed by ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) has been established for simultaneously quantitative determination of 135 pesticides and their metabolites (organophosphorus pesticides, pyrethroid pesticides and carbamate pesticides, etc.) in Angelica sinensis. The pesticide residues were extracted from the samples by acetonitrile, cleaned-up with a primary secondary amine (PSA) column and then analyzed using UFLC-MS/MS in multiple reaction monitoring (MRM) mode with positive electrospray ionization. The pesticide residues were quantified by matrix matched standard solution-internal standard method. All of the pesticides had good linear responses with r > 0.99. The average recoveries of the pesticides at the spiked levels of 10, 50, 100 μg/kg ranged from 71.3% - 119.7% with the RSDs of 1.0% - 19.9%, except for clethodim (62.0% - 68.2%). The limits of quantification of the 135 pesticides and their metabolites were 1.0-10.0 μg/kg. The results demonstrated that the method is simple, fast, sensitive and can be used for the analysis of the multiclass of pesticide residues in Angelica sinensis. PMID:27097459

  5. Determination of pharmaceuticals, steroid hormones, and endocrine-disrupting personal care products in sewage sludge by ultra-high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Yu, Yiyi; Huang, Qiuxin; Cui, Jianlan; Zhang, Kun; Tang, Caiming; Peng, Xianzhi

    2011-01-01

    A sensitive method has been developed and validated for the determination of diverse groups of pharmaceuticals, steroid hormones, and hormone-like personal care products in sewage sludge. Samples were extracted by ultrasonic-assisted extraction followed by solid-phase extraction cleanup. For determination of estrogens and hormone-like phenolic compounds, sample extracts were further derivatized with dansyl chloride and purified with silica gel column chromatography to improve the analytical sensitivity. The chemicals were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in multiple-reaction monitoring mode. Recoveries ranged mostly from 63% to 119% with relative standard deviations within 15%. Method quantification limits were 0.1-3 ng g(-1) dry weight (dw) for sewage sludge. The method was applied to a preliminary investigation of pharmaceuticals and personal care products (PPCPs) in sewage sludge and sediment in the Pearl River Delta, South China. Triclosan, triclocarban, 2-phenylphenol, bisphenol A, and parabens were ubiquitously detected at 3.6-5088.2 ng g(-1) dw in sludge and 0.29-113.1 ng g(-1) dw in sediment samples, respectively. Estrone, carbamazepine, metoprolol, and propranolol were also frequently quantified in the sludge and sediment samples. The dewatering process caused no significant losses of these PPCPs in sewage sludge. PMID:21046090

  6. A novel liquid chromatography-tandem mass spectrometry method for determination of menadione in human plasma after derivatization with 3-mercaptopropionic acid.

    PubMed

    Liu, Ruijuan; Wang, Mengmeng; Ding, Li

    2014-10-01

    Menadione (VK3), an essential fat-soluble naphthoquinone, takes very important physiological and pathological roles, but its detection and quantification is challenging. Herein, a new method was developed for quantification of VK3 in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after derivatization with 3-mercaptopropionic acid via Michael addition reaction. The derivative had been identified by the mass spectra and the derivatization conditions were optimized by considering different parameters. The method was demonstrated with high sensitivity and a low limit of quantification of 0.03 ng mL(-1) for VK3, which is about 33-fold better than that for the direct analysis of the underivatized compound. The method also had good precision and reproducibility. It was applied in the determination of basal VK3 in human plasma and a clinical pharmacokinetic study of menadiol sodium diphosphate. Furthermore, the method for the quantification of VK3 using LC-MS/MS was reported in this paper for the first time, and it will provide an important strategy for the further research on VK3 and menadione analogs. PMID:25059129

  7. Bioanalysis of therapeutic peptides: differentiating between total and anti-drug antibody bound drug using liquid chromatography-tandem mass spectrometry quantitation.

    PubMed

    Heinig, Katja; Wirz, Thomas; Schick, Eginhard; Guenzi, Alberto

    2013-11-01

    An acylated peptide with MW ~4.5 kDa was measured in samples from pharmacokinetic, toxicology and clinical studies using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lower limits of quantitation of 2 ng/mL and 50 pg/mL were achieved for animal and human plasma, respectively. Repeated drug administration may lead to anti-drug antibodies (ADA) which can inactivate the drug by formation of drug-ADA complexes. Hence, the LC-MS/MS assay incorporated cleavage of potential drug-ADA complexes to quantify the total plasma concentration. To obtain information on active drug levels, an assay that measures the free concentration or alternatively the ADA-unbound concentration would be needed. Ultrafiltration experiments through 100 kD cutoff membranes to remove Ig-bound peptide were not successful due to nonspecific binding. Extraction of Ig-bound drug using Protein A or G (bacterial cell wall proteins with high affinity to the Fc region of IgG) was suitable to distinguish between ADA-bound drug and [free+protein bound (not ADA-bound)] drug and correlated with findings from ELISA ADA measurement. PMID:24119751

  8. Simultaneous high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) analysis of cyanide and thiocyanate from swine plasma.

    PubMed

    Bhandari, Raj K; Manandhar, Erica; Oda, Robert P; Rockwood, Gary A; Logue, Brian A

    2014-01-01

    An analytical procedure for the simultaneous determination of cyanide and thiocyanate in swine plasma was developed and validated. Cyanide and thiocyanate were simultaneously analyzed by high-performance liquid chromatography tandem mass spectrometry in negative ionization mode after rapid and simple sample preparation. Isotopically labeled internal standards, Na(13)C(15)N and NaS(13)C(15)N, were mixed with swine plasma (spiked and nonspiked), proteins were precipitated with acetone, the samples were centrifuged, and the supernatant was removed and dried. The dried samples were reconstituted in 10 mM ammonium formate. Cyanide was reacted with naphthalene-2,3-dicarboxaldehyde and taurine to form N-substituted 1-cyano[f]benzoisoindole, while thiocyanate was chemically modified with monobromobimane to form an SCN-bimane product. The method produced dynamic ranges of 0.1-50 and 0.2-50 μM for cyanide and thiocyanate, respectively, with limits of detection of 10 nM for cyanide and 50 nM for thiocyanate. For quality control standards, the precision, as measured by percent relative standard deviation, was below 8 %, and the accuracy was within ±10 % of the nominal concentration. Following validation, the analytical procedure successfully detected cyanide and thiocyanate simultaneously from the plasma of cyanide-exposed swine. PMID:24327078

  9. Micro-solid phase extraction with liquid chromatography-tandem mass spectrometry for the determination of aflatoxins in coffee and malt beverage.

    PubMed

    Khayoon, Wejdan Shakir; Saad, Bahruddin; Salleh, Baharuddin; Manaf, Normaliza Hj Abdul; Latiff, Aishah A

    2014-03-15

    A single step extraction-cleanup procedure using porous membrane-protected micro-solid phase extraction (μ-SPE) in conjunction with liquid chromatography-tandem mass spectrometry for the extraction and determination of aflatoxins (AFs) B1, B2, G1 and G2 from food was successfully developed. After the extraction, AFs were desorbed from the μ-SPE device by ultrasonication using acetonitrile. The optimum extraction conditions were: sorbent material, C8; sorbent mass, 20mg; extraction time, 90 min; stirring speed, 1,000 rpm; sample volume, 10 mL; desorption solvent, acetonitrile; solvent volume, 350 μL and ultrasonication period, 25 min without salt addition. Under the optimum conditions, enrichment factor of 11, 9, 9 and 10 for AFG2, AFG1, AFB2 and AFB1, respectively were achieved. Good linearity and correlation coefficient was obtained over the concentration range of 0.4-50 ng g(-1) (r(2) 0.9988-0.9999). Good recoveries for AFs ranging from 86.0-109% were obtained. The method was applied to 40 samples involving malt beverage (19) and canned coffee (21). No AFs were detected in the selected samples. PMID:24206720

  10. Determination of multiple mycotoxins in dietary supplements containing green coffee bean extracts using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).

    PubMed

    Vaclavik, Lukas; Vaclavikova, Marta; Begley, Timothy H; Krynitsky, Alexander J; Rader, Jeanne I

    2013-05-22

    An ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of 34 mycotoxins in dietary supplements containing green coffee bean (GCB) extracts was developed, evaluated, and used in the analysis of 50 commercial products. A QuEChERS-like procedure was used for isolation of target analytes from the examined matrices. Average recoveries of the analytes were in the range of 75-110%. The precision of the method expressed as relative standard deviation was below 12%. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 1.0 to 50.0 μg/kg and from 2.5 to 100 μg/kg, respectively. Due to matrix effects, the method of standard additions was used to ensure accurate quantitation. Ochratoxin A, ochratoxin B, fumonisin B1 and mycophenolic acid were found in 36%, 32%, 10%, and 16% of tested products, respectively. Mycotoxins occurred in the following concentration ranges: ochratoxin A, <1.0-136.9 μg/kg; ochratoxin B, <1.0-20.2 μg/kg; fumonisin B1, <50.0-415.0 μg/kg; mycophenolic acid, <5.0-395.0 μg/kg. High-resolution mass spectrometry operated in full MS and MS/MS mode was used to confirm the identities of the reported compounds. PMID:23631685

  11. Analysis of 76 veterinary pharmaceuticals from 13 classes including aminoglycosides in bovine muscle by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    Dasenaki, Marilena E; Michali, Christina S; Thomaidis, Nikolaos S

    2016-06-24

    A multiresidue/multiclass method for the simultaneous determination of 76 veterinary drugs and pharmaceuticals in bovine muscle tissue has been developed and validated according to the requirements of European Commission Decision 2002/657/EC. The analytes belong in 13 different classes, including aminoglycoside antibiotics, whose different physicochemical properties (extremely polar character) render their simultaneous determination with other veterinary drugs quite problematic. The method combines a two-step extraction procedure (extraction with acetonitrile followed by an acidic aqueous buffer extraction) with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) determination, allowing confirmation and quantification in a single chromatographic run. Further cleanup with solid phase extraction was performed using polymeric SPE cartridges. A thorough ionization study of aminoglycosides was performed in order to increase their sensitivity and significant differences in the abundance of the precursor ions of the analytes were revealed, depending on the composition of the mobile phase tested. Further gradient elution optimization and injection solvent optimization were performed for all target analytes.The method was validated according to the European Commission Decision 2002/657. Quantitative analysis was performed by means of standard addition calibration. Recoveries varied from 37.4% (bromhexine) to 106% (kanamycin) in the lowest validation level and 82% of the compounds showed recovery >70%. Detection capability (CCβ) varied from 2.4 (salinomycin) to 1302 (apramycin) μgkg(-1). PMID:27215463

  12. Simultaneous absolute quantification of 11 cytochrome P450 isoforms in human liver microsomes by liquid chromatography tandem mass spectrometry with in silico target peptide selection.

    PubMed

    Kawakami, Hirotaka; Ohtsuki, Sumio; Kamiie, Junichi; Suzuki, Takashi; Abe, Takaaki; Terasaki, Tetsuya

    2011-01-01

    Cytochrome P450 (CYP) proteins are involved in the biological oxidation and reduction of xenobiotics, affecting the pharmacological efficiency of drugs. This study aimed to establish a method to simultaneously quantify 11 CYP isoforms by multiplexed-multiple reaction monitoring analysis with liquid chromatography tandem mass spectrometry and in silico peptide selection to clarify CYP isoform expression profiles in human liver tissue. CYP1A2, 2A6, and 2D6 target peptides were identified by shot-gun proteomic analysis, and those of other isoforms were selected by in silico peptide selection criteria. The established quantification method detected target peptides at 10  fmol, and the dynamic range of calibration curves was at least 500-fold. The quantification value of CYP1A2 in Supersomes was not significantly different between the established method and quantitative immunoblot analysis. The absolute protein expression levels of 11 CYP isoforms were determined from one pooled and 10 individual human liver microsomes. In the individual microsomes, CYP2C9 showed the highest protein expression level, and CYP1A2, 2A6, 2C19, and 3A4 protein expression exhibited more than a 20-fold difference among individuals. This highly sensitive and selective quantification method is a useful tool for the analysis of highly homologous CYP isoforms and the contribution made by each CYP isoform to drug metabolism. PMID:20564338

  13. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the direct detection of 2-monochloropropanediol (2-MCPD) esters in edible oils.

    PubMed

    MacMahon, Shaun; Ridge, Clark D; Begley, Timothy H

    2014-12-01

    A new analytical method has been developed and validated for the detection and quantification of 2-monochloropropanediol (2-MCPD) esters in edible oils. The target compounds are potentially carcinogenic contaminants formed during the processing of edible oils. As the 2-MCPD esters that occur most frequently in refined edible oils were not commercially available, standards were synthesized with identity and purity (95+%) confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and (1)H NMR. Target analytes are separated from edible oil matrices using a two-step solid-phase extraction (SPE) procedure. The extracts are then analyzed using LC-MS/MS with electrospray ionization (ESI). The method has been validated for 11 2-MCPD diesters and 3 2-MCPD monoesters in soybean oil, olive oil, and palm oil using an external calibration curve. The ranges of average recoveries and relative standard deviations (RSD) across the three oil matrices at three spiking concentrations are 79-106% (3-13% RSD) for the 2-MCPD diesters and 72-108% (4-17% RSD) for the 2-MCPD monoesters, with limits of quantitation at or below 30 ng/g for the diesters and 90 ng/g for the monoesters. PMID:25383913

  14. Liquid chromatography-tandem mass spectrometric methods for the determination of spinosad, thiacloprid and pyridalyl in spring onions and estimation of their pre-harvest interval values.

    PubMed

    Dasenaki, Marilena E; Bletsou, Anna A; Hanafi, Ahmad H; Thomaidis, Nikolaos S

    2016-12-15

    Two liquid chromatography-tandem mass spectrometric methods were developed and validated to determine spinosyn A and D, thiacloprid and pyridalyl in spring onions cultivated under Egyptian field conditions. The degradation rates, the pre-harvest interval (PHI) values and the half-life values of the three pesticides were estimated. QuEChERS was used for sample preparation and the separation was performed on an X-Bridge C18 column with ACN-formic acid 0.1% as the mobile phase. Linear range, method detection limits (MDLs), precision, recovery and matrix effects were estimated. The multi-residue MDLs ranged from 0.02μg/kg (spinosyn A & D) to 0.05μg/kg for pyridalyl. All the investigated pesticides showed high degradation rates. For spinosad the half-life value was 1.2days, for thiacloprid it reached 2.2days and for pyridalyl 4.4days. Furthermore, the calculated PHI values, according to the maximum residue levels set by the EU, were 0days for spinosad, 9.8days for thiacloprid and 39.4days for pyridalyl. PMID:27451196

  15. [Determination of benzoylurea and bishydrazide pesticide residues in vegetables by ultra performance liquid chromatography-tandem mass spectrometry with matrix solid phase dispersion].

    PubMed

    Han, Xiao; Lou, Xishan; Zhang, Li; Wang, Guoqing; Ma, Ming; Wang, Minglin

    2010-04-01

    A method for the determination of nine pesticides including benzoylureas (diflubenzuron, chlorobenzuron, triflumuron, teflubenzuron, flufenoxuron, chlorfluazuron, hexaflumuron) and bishydrazides (methoxyfenozide, tebufenozide) in vegetables was developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with matrix solid phase dispersion. The sample was graphitized with neutral alumina as dispersant and carbon black as purifying, and eluted with ethyl acetate. The separation was achieved by UPLC, and then the identification and quantification were performed using MS/MS with multiple-reaction monitoring and electrospray ionization in positive or negative mode. The following results were obtained: The calibration curves showed good linearity in the ranges of 1-100 microg/L with R2 > or = 0.99. The recoveries were 78.5%-112.8% at four spiked levels of 1, 5, 10, 100 microg/kg, and the relative standard deviations were 2.3%-10.2%. The limits of determination were 0.5-1.0 microg/kg. The method has the advantages of easy to operate, fast to perform, lower limits of quantification, consuming less sample and organic solvents. It can meet the demands of practical use for the rapid and simultaneous determination of benzoylureas and bishydrazides in vegetables. PMID:20712114

  16. Simultaneous determination of neonicotinoid insecticides in human serum and urine using diatomaceous earth-assisted extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Yamamuro, Tadashi; Ohta, Hikoto; Aoyama, Mika; Watanabe, Daisuke

    2014-10-15

    A rapid and sensitive analytical method was developed for simultaneous determination of eight neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) and three specific metabolites of acetamiprid (N-desmethylacetamiprid, 5-(N-acetyl-N-methylaminomethyl)-2-chloropyridine and 5-(N-acetylaminomethyl)-2-chloropyridine) in human serum and urine. A diatomaceous earth-assisted extraction using Extrelut NT3 column with chloroform/2-propanol (3:1, v/v) as eluent was selected for the single step cleanup procedure for all the target compounds. Qualitative and quantitative analyses were conducted by liquid chromatography-tandem mass spectrometry with multiple reaction monitoring mode. The limits of detection and the limits of quantification of eleven compounds were in the ranges of 0.1-0.2ng/mL and 0.5-10ng/mL for serum, 0.1-1ng/mL and 1-10ng/mL for urine, respectively. The extraction recoveries were between 80.9% and 101.8% for serum samples, 91.9% and 106% for urine samples. The intra-day RSDs and the inter-day RSDs were less than 11.5% and 13.2% for serum, less than 8.3% and 8.8% for urine. The proposed procedure will be suitable for forensic investigations of human poisoning cases with neonicotinoid insecticides. This is the first report of simultaneous determination of eight neonicotinoids in serum and urine samples. PMID:25168791

  17. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column.

    PubMed

    Domingues, Diego Soares; Souza, Israel Donizeti de; Queiroz, Maria Eugênia Costa

    2015-07-01

    This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM). PMID:25984963

  18. Determination of cyantraniliprole and its major metabolite residues in vegetable and soil using ultra-performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Dong, Fengshou; Liu, Xingang; Xu, Jun; Li, Jing; Li, Yuanbo; Shan, Weili; Song, Wencheng; Zheng, Yongquan

    2012-03-01

    A rapid, highly sensitive and selective method was developed for the determination of the cyantraniliprole and its major metabolite J9Z38 in cucumber, tomato and soil by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Target compounds were extracted with acetonitrile and an aliquot cleaned with primary and secondary amine. Two pairs of precursor product ion transitions for cyantraniliprole and J9Z38 were measured and evaluated. Average recoveries for cucumber, tomato and soil at three levels (10, 50 and 100 µg/kg) ranged from 74.7 to 96.2% with intra-day relative standard deviation (RSD) of 2.6-15.1% and inter-day RSD of 3.4-13.3%. The limit of quantitation for cyantraniliprole and J9Z38 were determined to be 5 and 10 µg/kg in samples (cucumber, tomato and soil), respectively. This method was used to determine the cyantraniliprole and J9Z38 residues in real cucumber, tomato and soil samples for studies on their dissipation. The trial results showed that the half-lives of cyantraniliprole obtained after treatments were 2.2, 2.8 and 9.5 days in cucumber, tomato and soil in Zhejiang, respectively, and that the average levels of cyantraniliprole and J9Z38 residues in cucumber and tomato were all <0.01 mg/kg with the interval of 10 days after treatment. PMID:21710575

  19. Quantitative determination of estrone by liquid chromatography-tandem mass spectrometry in subcutaneous adipose tissue from the breast in postmenopausal women.

    PubMed

    Vihma, Veera; Wang, Feng; Savolainen-Peltonen, Hanna; Turpeinen, Ursula; Hämäläinen, Esa; Leidenius, Marjut; Mikkola, Tomi S; Tikkanen, Matti J

    2016-01-01

    Estrone is the most abundant estrogen after the menopause. We developed a liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for determination of estrone in adipose tissue. Subcutaneous adipose tissue from the breast was collected during elective surgery in postmenopausal women undergoing mastectomy for treatment of breast cancer (n=13) or reduction mammoplasty (controls, n=11). Homogenized adipose tissue was extracted with organic solvents and the estrone fraction was purified by LH-20 column chromatography from the excess of lipids. The concentration of estrone was analyzed by LC-MS/MS. The method was accurate with an intra-assay variation of 8% and an interassay variation of 10%. The median concentration of estrone in subcutaneous adipose tissue from the breast did not differ between breast cancer and control women, 920 pmol/kg and 890 pmol/kg, respectively. In breast cancer patients but not in the controls, breast adipose tissue estrone levels correlated positively with the serum estrone concentration. In conclusion, the new method provides a reliable means to measure estrone concentrations in adipose tissue in postmenopausal women. PMID:26472555

  20. Rapid discovery of putative protein biomarkers of traumatic brain injury by SDS-PAGE-capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Haskins, William E; Kobeissy, Firas H; Wolper, Regina A; Ottens, Andrew K; Kitlen, Jason W; McClung, Scott H; O'Steen, Barbara E; Chow, Marjorie M; Pineda, Jose A; Denslow, Nancy D; Hayes, Ronald L; Wang, Kevin K W

    2005-06-01

    We report the rapid discovery of putative protein biomarkers of traumatic brain injury (TBI) by SDS-PAGE-capillary liquid chromatography-tandem mass spectrometry (SDS-PAGE-Capillary LC-MS(2)). Ipsilateral hippocampus (IH) samples were collected from naive rats and rats subjected to controlled cortical impact (a rodent model of TBI). Protein database searching with 15,558 uninterpreted MS(2) spectra, collected in 3 days via data-dependent capillary LC-MS(2) of pooled cyanine dye-labeled samples separated by SDS-PAGE, identified more than 306 unique proteins. Differential proteomic analysis revealed differences in protein sequence coverage for 170 mammalian proteins (57 in naive only, 74 in injured only, and 39 of 64 in both), suggesting these are putative biomarkers of TBI. Confidence in our results was obtained by the presence of several known biomarkers of TBI (including alphaII-spectrin, brain creatine kinase, and neuron-specific enolase) in our data set. These results show that SDS-PAGE prior to in vitro proteolysis and capillary LC-MS(2) is a promising strategy for the rapid discovery of putative protein biomarkers associated with a specific physiological state (i.e., TBI) without a priori knowledge of the molecules involved. PMID:15941373

  1. Multiresidue analysis of sulfonamides, quinolones, and tetracyclines in animal tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Zhiwen; Li, Xiaowei; Ding, Shuangyang; Jiang, Haiyang; Shen, Jianzhong; Xia, Xi

    2016-08-01

    A multiresidue method for the efficient identification and quantification of 38 compounds from 3 different classes of antibiotics (tetracyclines, sulfonamides, and quinolones) in animal tissues has been developed. The method optimization involved the selection of extraction solutions, comparison of different solid-phase extraction cartridges and different mobile phases. As a result, the samples were extracted with Mcllvaine and phosphate buffers, followed by clean-up step based on solid-phase extraction with Oasis HLB cartridge. All compounds were determined by ultra-high performance liquid chromatography-tandem mass spectrometry, in one single injection with a chromatographic run time of only 9min. The method efficiency was evaluated in 5 tissues including muscle, liver, and kidney, and the mean recoveries ranged from 54% to 102%, with inter-day relative standard deviation lower than 14%. The limits of quantification were between 0.5 and 10μg/kg, which were satisfactory to support future surveillance monitoring. The developed method was applied to the analysis of swine liver and chicken samples from local markets, and sulfamethazine was the most commonly detected compound in the animal samples, with the highest residue level of 998μg/kg. PMID:26988500

  2. Combination of liquid-chromatography tandem mass spectrometry in different scan modes with human and chimeric mouse urine for the study of steroid metabolism.

    PubMed

    Pozo, Oscar J; Lootens, Leen; Van Eenoo, Peter; Deventer, Koen; Meuleman, Philip; Leroux-Roels, Geert; Parr, Maria K; Schänzer, Wilhelm; Delbeke, Frans T

    2009-11-01

    Anabolic steroids are among the most frequently detected compounds in doping analysis. They are extensively metabolized and therefore an in-depth knowledge about steroid metabolism is needed. In this study, a liquid chromatography tandem mass spectometry (LC-MS/MS) method based on a precursor ion scan with a uPA-SCID mouse with humanized liver (a chimeric mouse) was explored for the detection of steroid metabolism. Methandienone was used as a model compound. The application of the precursor ion scan method in positive human samples and chimeric mice samples after methandienone administration allowed the detection of most steroid metabolites without any structural restriction. Three hitherto unreported metabolites were found using this approach. These metabolites were characterized using LC-MS/MS and feasible structures were proposed. The structure of one of them, 6-ene-epimethandienone, was confirmed by the synthesis of the reference compound. A selected reaction monitoring (SRM) method for the specific detection of all these metabolites has been developed. The application of this method to several human and chimeric mouse samples confirmed that more than 80% of the steroid metabolites were found in both samples. Only metabolites that are poorly detectable by LC-MS/MS were not detected in some urine samples. The metabolic nature of the unreported metabolites was also confirmed. A global strategy for the detection of steroid metabolites combining both human and chimeric mouse urine is proposed. PMID:20355172

  3. Determination of Androgen Receptor Degradation Enhancer ASC-J9® in Mouse Sera and Organs with Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Soh, Shu Fang; Huang, Chiung-Kuei; Lee, Soo Ok; Xu, Defeng; Yeh, Shuyuan; Li, Jun; Yong, Eu Leong; Gong, Yinhan; Chang, Chawnshang

    2013-01-01

    A novel androgen receptor (AR) degradation enhancer ASC-J9® has displayed beneficial effects during the in vitro and in vivo studies for treatment of prostate cancer, liver cancer, bladder cancer and spinal and bulbar muscular atrophy (SBMA). It works mainly by inducing the degradation of AR with minimal side effects on the tested mice. Here we developed a fast, robust and more sensitive method for the quantification of ASC-J9® in 100 μL of mouse serum by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The limit of quantification (LOQ) was found to be 5nM for ASCJ9®. This method was successfully applied to investigate the pharmacokinetics of ASC-J9® in mice serum samples and also the distribution of the drug in various mice organs after single dose injection with results showing that ASC-J9® could be quickly absorbed in vivo and had a relatively slow elimination half-life of 5.45 h. The ASC-J9® also exhibited a higher tendency to accumulate in organs such as liver, testes and prostate. PMID:24042123

  4. A novelty strategy for the fast analysis of sulfonamide antibiotics in fish tissue using magnetic separation with high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Li, Jincheng; Liu, Huan; Zhang, Jing; Liu, Yang; Wu, Lidong

    2016-08-01

    A simple, fast and low-cost extraction method with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) determination was developed on sulfonamide antibiotics (SAs) in fish tissue. Magnetic separation was first introduced into the rapid sample preparation procedure combined with acetonitrile extraction for the analysis of SAs. Partitioning was rapidly achieved between acetonitrile solution and solid matrix by applying an external magnetic field. Acetonitrile solution was collected and concentrated under a nitrogen stream. The residue was redissolved with 1‰ formic acid aqueous solution and defatted with n-hexane before analysis. The recoveries of SAs were in the range of 74.87-104.74%, with relative standard deviations <13%. The limits of quantification and the limits of detection for SAs ranged from 5.0 to 25.0 μg (kg-1) and from 2.5 to 10.0 μg (kg-1) , respectively. The presented extraction method proved to be a rapid method which only took 20 min for one sample preparation procedure. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26849706

  5. Determination of quinolones of veterinary use in bee products by ultra-high performance liquid chromatography-tandem mass spectrometry using a QuEChERS extraction procedure.

    PubMed

    Lombardo-Agüí, Manuel; García-Campaña, Ana M; Gámiz-Gracia, Laura; Cruces-Blanco, Carmen

    2012-05-15

    A reliable and rapid ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the determination of the eight quinolones of veterinary use regulated by European Union (marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, flumequine and oxolinic acid). Chromatographic conditions were optimized in order to increase sample throughput and sensitivity. The antibiotics were detected by electrospray ionization in positive ion mode with multiple reaction monitoring (MRM) and MS/MS conditions were optimized in order to increase selectivity, selecting the corresponding product ions for quantification and identification. The separation was achieved in 3 min, using a Zorbax Eclipse Plus C18 column (50 mm × 2.1mm, 1.8 μm), with a mobile phase of 0.02% aqueous formic acid solution and acetonitrile. A dispersive solid phase extraction methodology, often referred to as the "QuEChERS" (quick, easy, cheap, effective, rugged, and safe) method, was optimized for extraction of the quinolones from honey and also it was evaluated for other bee products such as royal jelly and propolis. The method was validated for each matrix in terms of linearity, trueness, precision, limits of detection (LODs) and quantification (LOQ). LODs ranged between 0.2 and 4.1 μg kg(-1) with precision lower than 12% and satisfactory recoveries in most cases. The method was also applied for studying the occurrence of these antibiotics in several market samples. PMID:22483898

  6. Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatography-tandem mass spectrometry.

    PubMed

    El-Beqqali, Aziza; Abdel-Rehim, Mohamed

    2016-09-14

    In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5-5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r(2)) values were ≥0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples. PMID:27566346

  7. Hydrophilic-interaction liquid chromatography-tandem mass spectrometric determination of erythrocyte 5-phosphoribosyl 1-pyrophosphate in patients with hypoxanthine-guanine phosphoribosyltransferase deficiency.

    PubMed

    Hasegawa, Hiroshi; Shinohara, Yoshihiko; Nozaki, Sayako; Nakamura, Makiko; Oh, Koei; Namiki, Osamu; Suzuki, Kiyotaka; Nakahara, Akihiko; Miyazawa, Mari; Ishikawa, Ken; Himeno, Takahiro; Yoshida, Sayaka; Ueda, Takanori; Yamada, Yasukazu; Ichida, Kimiyoshi

    2015-01-22

    Mutations in the gene encoding hypoxanthine-guanine phosphoribosyltransferase (HPRT) cause Lesch-Nyhan disease (LND) and its variants (LNV). Due to the technical problems for measuring the HPRT activity in vitro, discordances between the residual HPRT activity and the clinical severity were found. 5-Phosphoribosyl 1-pyrophosphate (PRPP) is a substrate for HPRT. Since increased PRPP concentrations were observed in erythrocytes from patients with LND and LNV, we have turned our attention to erythrocyte PRPP as a biomarker for the phenotype classification. In the present work, a method for determination of PRPP concentration in erythrocyte was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM). Packed erythrocyte samples were deproteinized by heating and the supernatants were injected into the LC-MS/MS system. All measurement results showed good precision with RSD <6%. PRPP concentrations of nine normal male subjects, four male patents with LND and six male patients with LNV were compared. The PRPP concentrations in erythrocyte from patients with LND were markedly increased compared with those from normal subjects, and those from patients with LNV were also increased but the degree was smaller than those with LND. The increase pattern of PRPP concentration in erythrocyte from patients with HPRT deficiency was consistent with the respective phenotypes and was correlated with the disease severity. PRPP concentration was suggested to give us supportive information for the diagnosis and the phenotype classification of LND and LNV. PMID:25482009

  8. Pharmacokinetic Study of 14-(3-Methylbenzyl)matrine and 14-(4-Methylbenzyl)matrine in Rat Plasma Using Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Jiang, Minjie; Wang, Lisheng; Huang, Shulin; Xu, Liba; Hu, Chao; Jiang, Weizhe

    2015-01-01

    A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS) was developed and validated to determine the 14-(3-methylbenzyl)matrine (3MBM) and 14-(4-methylbenzyl)matrine (4MBM) levels in rat plasma in the present study. The analytes were separated using a C18 column (1.9 μm, 2.1 mm × 100 mm) equipped with a Security Guard C18 column (5 μm, 2.1 mm × 10 mm), followed by detection via triple-quadrupole mass spectrometry using an electrospray ionization (ESI) source. Sample pretreatment involved one-step protein precipitation with isopropanol:ethyl acetate (v/v, 25:75), and pseudoephedrine hydrochloride was used as an internal standard. The method was linear in the concentration range of 5–2000 ng/ml for both compounds. The intra-day and inter-day relative standard deviations (RSDs) were less than 15%, and all relative errors (REs) were within 15%. The proposed method enables the unambiguous identification and quantification of these two compounds in vivo. This study is the first to determine the 3MBM and 4MBM levels in rat plasma after oral administration of these compounds. These results provide a meaningful basis for evaluating the clinical applications of these medicines. PMID:25714369

  9. Method validation and dissipation kinetics of four herbicides in maize and soil using QuEChERS sample preparation and liquid chromatography tandem mass spectrometry.

    PubMed

    Pang, Nannan; Wang, Tielong; Hu, Jiye

    2016-01-01

    A versatile liquid chromatography tandem mass spectrometry method with modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation was developed for the determination of rimsulfuron, mesotrione, fluroxypyr-meptyl, and fluroxypyr. By adjusting the amount of graphitized carbon black, the herbicide analytes could be quantified with satisfactory recoveries in the range of 80-110%. A dissipation kinetics study conducted under open field conditions at two sites during 2014 showed first order equations with half-lives between 0.6d and 3.6d, illustrating an appropriate degree of stability and safety. The dissipation kinetics were different in the different matrices. Although the herbicides had higher initial residues in straw than those in soil, they degraded faster in straw. The terminal residues for the herbicides formulated in two water dispersible granules were all below maximum residue limits. These results not only gave insights about the analytes but also contributed to environmental protection and food safety. PMID:26213040

  10. Quantitation of sorafenib and its active metabolite sorafenib N-oxide in human plasma by liquid chromatography-tandem mass spectrometry.