Validation of a hydride generation atomic absorption spectrometry methodology for determination of mercury in fish designed for application in the Brazilian national residue control plan.

PubMed

Damin, Isabel C F; Santo, Maria A E; Hennigen, Rosmari; Vargas, Denise M

2013-01-01

In the present study, a method for the determination of mercury (Hg) in fish was validated according to ISO/IEC 17025, INMETRO (Brazil), and more recent European recommendations (Commission Decision 2007/333/EC and 2002/657/EC) for implementation in the Brazilian Residue Control Plan (NRCP) in routine applications. The parameters evaluated in the validation were investigated in detail. The results obtained for limit of detection and quantification were respectively, 2.36 and 7.88 μg kg(-1) of Hg. While the recovery varies between 90-96%. The coefficient of variation was of 4.06-8.94% for the repeatability. Furthermore, a comparison using an external proficiency testing scheme was realized. The results of method validated for the determination of the mercury in fish by Hydride generation atomic absorption spectrometry were considered suitable for implementation in routine analysis.

Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

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

USDA-ARS?s Scientific Manuscript database

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...

Bio-analytical method development and validation of Rasagiline by high performance liquid chromatography tandem mass spectrometry detection and its application to pharmacokinetic study

PubMed Central

Konda, Ravi Kumar; Chandu, Babu Rao; Challa, B.R.; Kothapalli, Chandrasekhar B.

2012-01-01

The most suitable bio-analytical method based on liquid–liquid extraction has been developed and validated for quantification of Rasagiline in human plasma. Rasagiline-13C3 mesylate was used as an internal standard for Rasagiline. Zorbax Eclipse Plus C18 (2.1 mm×50 mm, 3.5 μm) column provided chromatographic separation of analyte followed by detection with mass spectrometry. The method involved simple isocratic chromatographic condition and mass spectrometric detection in the positive ionization mode using an API-4000 system. The total run time was 3.0 min. The proposed method has been validated with the linear range of 5–12000 pg/mL for Rasagiline. The intra-run and inter-run precision values were within 1.3%–2.9% and 1.6%–2.2% respectively for Rasagiline. The overall recovery for Rasagiline and Rasagiline-13C3 mesylate analog was 96.9% and 96.7% respectively. This validated method was successfully applied to the bioequivalence and pharmacokinetic study of human volunteers under fasting condition. PMID:29403764

75 FR 14154 - Notice of Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-24

... for plant commodities) are both gas liquid chromatography (GLC) methods with electron capture... analytical methodology using liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) detection...-aminopropane]) using gas chromatography (GC) have been submitted to the EPA. In addition, a new validated...

Single Laboratory Validated Method for Determination of Cylindrospermopsin and Anatoxin-a in Ambient Water by Liquid Chromatography/ Tandem Mass Spectrometry (LC/MS/MS)

EPA Science Inventory

This product is an LC/MS/MS single laboratory validated method for the determination of cylindrospermopsin and anatoxin-a in ambient waters. The product contains step-by-step instructions for sample preparation, analyses, preservation, sample holding time and QC protocols to ensu...

Development and validation of a liquid chromatography-isotope dilution tandem mass spectrometry for determination of olanzapine in human plasma and its application to bioavailability study.

PubMed

Zhang, Meng-Qi; Jia, Jing-Ying; Lu, Chuan; Liu, Gang-Yi; Yu, Cheng-Yin; Gui, Yu-Zhou; Liu, Yun; Liu, Yan-Mei; Wang, Wei; Li, Shui-Jun; Yu, Chen

2010-06-01

A simple, reliable and sensitive liquid chromatography-isotope dilution mass spectrometry (LC-ID/MS) was developed and validated for quantification of olanzapine in human plasma. Plasma samples (50 microL) were extracted with tert-butyl methyl ether and isotope-labeled internal standard (olanzapine-D3) was used. The chromatographic separation was performed on XBridge Shield RP 18 (100 mm x 2.1 mm, 3.5 microm, Waters). An isocratic program was used at a flow rate of 0.4 m x min(-1) with mobile phase consisting of acetonitrile and ammonium buffer (pH 8). The protonated ions of analytes were detected in positive ionization by multiple reactions monitoring (MRM) mode. The plasma method, with a lower limit of quantification (LLOQ) of 0.1 ng x mL(-1), demonstrated good linearity over a range of 0.1 - 30 ng x mL(-1) of olanzapine. Specificity, linearity, accuracy, precision, recovery, matrix effect and stability were evaluated during method validation. The validated method was successfully applied to analyzing human plasma samples in bioavailability study.

Validation of an analytical method for nitrous oxide (N2O) laughing gas by headspace gas chromatography coupled to mass spectrometry (HS-GC-MS): forensic application to a lethal intoxication.

PubMed

Giuliani, N; Beyer, J; Augsburger, M; Varlet, V

2015-03-01

Drug abuse is a widespread problem affecting both teenagers and adults. Nitrous oxide is becoming increasingly popular as an inhalation drug, causing harmful neurological and hematological effects. Some gas chromatography-mass spectrometry (GC-MS) methods for nitrous oxide measurement have been previously described. The main drawbacks of these methods include a lack of sensitivity for forensic applications; including an inability to quantitatively determine the concentration of gas present. The following study provides a validated method using HS-GC-MS which incorporates hydrogen sulfide as a suitable internal standard allowing the quantification of nitrous oxide. Upon analysis, sample and internal standard have similar retention times and are eluted quickly from the molecular sieve 5Å PLOT capillary column and the Porabond Q column therefore providing rapid data collection whilst preserving well defined peaks. After validation, the method has been applied to a real case of N2O intoxication indicating concentrations in a mono-intoxication. Copyright © 2015 Elsevier B.V. All rights reserved.

Validation of a method to detect cocaine and its metabolites in nails by gas chromatography-mass spectrometry.

PubMed

Valente-Campos, Simone; Yonamine, Mauricio; de Moraes Moreau, Regina Lucia; Silva, Ovandir Alves

2006-06-02

The objective of the present work was to compare previously published methods and provide validation data to detect simultaneously cocaine (COC), benzoylecgonine (BE) and norcocaine (NCOC) in nail. Finger and toenail samples (5mg) were cut in very small pieces and submitted to an initial procedure for external decontamination. Methanol (3 ml) was used to release analytes from the matrix. A cleanup step was performed simultaneously by solid-phase extraction (SPE) and the residue was derivatized with pentafluoropropionic anhydride/pentafluoropropanol (PFPA/PFP). Gas chromatography-mass spectrometry (GC-MS) was used to detect the analytes in selected ion monitoring mode (SIM). Confidence parameters of validation of the method were: recovery, intra- and inter-assay precision, as well as limit of detection (LOD) of the analytes. The limits of detection were: 3.5 ng/mg for NCOC and 3.0 ng/mg for COC and BE. Good intra-assay precision was observed for all detected substances (coefficient of variation (CV)<11%). The inter-assay precision for norcocaine and benzoylecgonine were <4%. For intra- and inter-assay precision deuterated internal standards were used. Toenail and fingernail samples from eight declared cocaine users were submitted to the validated method.

Analysis of wine volatile profile by purge-and-trap-gas chromatography-mass spectrometry. Application to the analysis of red and white wines from different Spanish regions.

PubMed

Aznar, Margarita; Arroyo, Teresa

2007-09-21

The purge-and-trap extraction method, coupled to a gas chromatograph with mass spectrometry detection, has been applied to the determination of 26 aromatic volatiles in wine. The method was optimized, validated and applied to the analyses of 40 red and white wines from 7 different Spanish regions. Principal components analyses of data showed the correlation between wines of similar origin.

Determination of Phosphorus and Potassium in Commercial Inorganic Fertilizers by Inductively Coupled Plasma-Optical Emission Spectrometry: Single-Laboratory Validation, First Action 2015.18.

PubMed

Thiex, Nancy J

2016-07-01

A previously validated method for the determination of both citrate-EDTA-soluble P and K and acid-soluble P and K in commercial inorganic fertilizers by inductively coupled plasma-optical emission spectrometry was submitted to the expert review panel (ERP) for fertilizers for consideration of First Action Official Method(SM) status. The ERP evaluated the single-laboratory validation results and recommended the method for First Action Official Method status and provided recommendations for achieving Final Action. Validation materials ranging from 4.4 to 52.4% P2O5 (1.7-22.7% P) and 3-62% K2O (2.5-51.1% K) were used for the validation. Recoveries from validation materials for citrate-soluble P and K ranged from 99.3 to 124.9% P and from 98.4 to 100.7% K. Recoveries from validation materials for acid-soluble "total" P and K ranged from 95.53 to 99.40% P and from 98.36 to 107.28% K. Values of r for citrate-soluble P and K, expressed as RSD, ranged from 0.28 to 1.30% for P and from 0.41 to 1.52% for K. Values of r for total P and K, expressed as RSD, ranged from 0.71 to 1.13% for P and from 0.39 to 1.18% for K. Based on the validation data, the ERP recommended the method (with alternatives for the citrate-soluble and the acid-soluble extractions) for First Action Official Method status and provided recommendations for achieving Final Action status.

Development and Validation of an Analytical Methodology Based on Liquid Chromatography-Electrospray Tandem Mass Spectrometry for the Simultaneous Determination of Phenolic Compounds in Olive Leaf Extract.

PubMed

Cittan, Mustafa; Çelik, Ali

2018-04-01

A simple method was validated for the analysis of 31 phenolic compounds using liquid chromatography-electrospray tandem mass spectrometry. Proposed method was successfully applied to the determination of phenolic compounds in an olive leaf extract and 24 compounds were analyzed quantitatively. Olive biophenols were extracted from olive leaves by using microwave-assisted extraction with acceptable recovery values between 78.1 and 108.7%. Good linearities were obtained with correlation coefficients over 0.9916 from calibration curves of the phenolic compounds. The limits of quantifications were from 0.14 to 3.2 μg g-1. Intra-day and inter-day precision studies indicated that the proposed method was repeatable. As a result, it was confirmed that the proposed method was highly reliable for determination of the phenolic species in olive leaf extracts.

Capsule Typing of Haemophilus influenzae by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

PubMed

Månsson, Viktor; Gilsdorf, Janet R; Kahlmeter, Gunnar; Kilian, Mogens; Kroll, J Simon; Riesbeck, Kristian; Resman, Fredrik

2018-03-01

Encapsulated Haemophilus influenzae strains belong to type-specific genetic lineages. Reliable capsule typing requires PCR, but a more efficient method would be useful. We evaluated capsule typing by using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Isolates of all capsule types (a-f and nontypeable; n = 258) and isogenic capsule transformants (types a-d) were investigated. Principal component and biomarker analyses of mass spectra showed clustering, and mass peaks correlated with capsule type-specific genetic lineages. We used 31 selected isolates to construct a capsule typing database. Validation with the remaining isolates (n = 227) showed 100% sensitivity and 92.2% specificity for encapsulated strains (a-f; n = 61). Blinded validation of a supplemented database (n = 50) using clinical isolates (n = 126) showed 100% sensitivity and 100% specificity for encapsulated strains (b, e, and f; n = 28). MALDI-TOF mass spectrometry is an accurate method for capsule typing of H. influenzae.

Method validation for simultaneous determination of chromium, molybdenum and selenium in infant formulas by ICP-OES and ICP-MS.

PubMed

Khan, Naeem; Jeong, In Seon; Hwang, In Min; Kim, Jae Sung; Choi, Sung Hwa; Nho, Eun Yeong; Choi, Ji Yeon; Kwak, Byung-Man; Ahn, Jang-Hyuk; Yoon, Taehyung; Kim, Kyong Su

2013-12-15

This study aimed to validate the analytical method for simultaneous determination of chromium (Cr), molybdenum (Mo), and selenium (Se) in infant formulas available in South Korea. Various digestion methods of dry-ashing, wet-digestion and microwave were evaluated for samples preparation and both inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) were compared for analysis. The analytical techniques were validated by detection limits, precision, accuracy and recovery experiments. Results showed that wet-digestion and microwave methods were giving satisfactory results for sample preparation, while ICP-MS was found more sensitive and effective technique than ICP-OES. The recovery (%) of Se, Mo and Cr by ICP-OES were 40.9, 109.4 and 0, compared to 99.1, 98.7 and 98.4, respectively by ICP-MS. The contents of Cr, Mo and Se in infant formulas by ICP-MS were found in good nutritional values in accordance to nutrient standards for infant formulas CODEX values. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development and Validation of a Multiplexed Protein Quantitation Assay for the Determination of Three Recombinant Proteins in Soybean Tissues by Liquid Chromatography with Tandem Mass Spectrometry.

PubMed

Hill, Ryan C; Oman, Trent J; Shan, Guomin; Schafer, Barry; Eble, Julie; Chen, Cynthia

2015-08-26

Currently, traditional immunochemistry technologies such as enzyme-linked immunosorbent assays (ELISA) are the predominant analytical tool used to measure levels of recombinant proteins expressed in genetically engineered (GE) plants. Recent advances in agricultural biotechnology have created a need to develop methods capable of selectively detecting and quantifying multiple proteins in complex matrices because of increasing numbers of transgenic proteins being coexpressed or "stacked" to achieve tolerance to multiple herbicides or to provide multiple modes of action for insect control. A multiplexing analytical method utilizing liquid chromatography with tandem mass spectrometry (LC-MS/MS) has been developed and validated to quantify three herbicide-tolerant proteins in soybean tissues: aryloxyalkanoate dioxygenase (AAD-12), 5-enol-pyruvylshikimate-3-phosphate synthase (2mEPSPS), and phosphinothricin acetyltransferase (PAT). Results from the validation showed high recovery and precision over multiple analysts and laboratories. Results from this method were comparable to those obtained with ELISA with respect to protein quantitation, and the described method was demonstrated to be suitable for multiplex quantitation of transgenic proteins in GE crops.

Method validation for 243 pesticides and environmental contaminants in meats and poultry by tandem mass spectrometry coupled to low-pressure gas chromatography and ultra high-performance liquid chromatography

USDA-ARS?s Scientific Manuscript database

An easy and reliable high-throughput analysis method was developed and validated for 192 diverse pesticides and 51 environmental contaminants (13 PCB congeners, 14 PAHs, 7 PBDE congeners, and 17 novel flame retardants) in cattle, swine, and poultry muscle. Sample preparation was based on the “quick,...

Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Hok, S; Alcaraz, A

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 limitmore » 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.« less

Simultaneous analysis by Quadrupole-Orbitrap mass spectrometry and UHPLC-MS/MS for the determination of sedative-hypnotics and sleep inducers in adulterated products.

PubMed

Lee, Ji Hyun; Park, Han Na; Choi, Ji Yeon; Kim, Nam Sook; Park, Hyung-Joon; Park, Seong Soo; Baek, Sun Young

2017-12-01

Adulterated products are continuously detected in society and cause problems. In this study, we developed and validated a method for determining synthetic sedative-hypnotics and sleep inducers, including barbital, benzodiazepam, zolpidem, and first-generation antihistamines, in adulterated products using Quadrupole-Orbitrap mass spectrometry and ultrahigh performance liquid chromatography with tandem mass spectrometry. In Quadrupole-Orbitrap mass spectrometry analysis, target compounds were confirmed using a combination of retention time, mass tolerance, mass accuracy, and fragment ions. For quantification, several validation parameters were employed using ultrahigh performance liquid chromatography with tandem mass spectrometry. The limit of detection and limit of quantitation was 0.05-53 and 0.17-177 ng/mL, respectively. The correlation coefficient for linearity was more than 0.995. The intra- and interassay accuracies were 86-110 and 84-111%, respectively. Their precision values were evaluated as within 4.0 (intraday) and 10.7% (interday). Mean recoveries of target compounds in adulterated products ranged from 85 to 116%. The relative standard deviation of stability was less than 10.7% at 4°C for 48 h. The 144 adulterated products obtained over 3 years (2014-2016) from online and in-person vendors were tested using established methods. After rapidly screening with Quadrupole-Orbitrap mass spectrometry, the detected samples were quantified using ultrahigh performance liquid chromatography with tandem mass spectrometry. Two of them were adulterated with phenobarbital. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mass spectrometry for biomarker development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Chaochao; Liu, Tao; Baker, Erin Shammel

2015-06-19

Biomarkers potentially play a crucial role in early disease diagnosis, prognosis and targeted therapy. In the past decade, mass spectrometry based proteomics has become increasingly important in biomarker development due to large advances in technology and associated methods. This chapter mainly focuses on the application of broad (e.g. shotgun) proteomics in biomarker discovery and the utility of targeted proteomics in biomarker verification and validation. A range of mass spectrometry methodologies are discussed emphasizing their efficacy in the different stages in biomarker development, with a particular emphasis on blood biomarker development.

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. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd.

Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

PubMed

Zacs, D; Bartkevics, V

2015-10-22

A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Single laboratory validation of the determination of yohimbine in yohimbe bark and related dietary supplements using UHPLC/UV/MS

USDA-ARS?s Scientific Manuscript database

A single laboratory validation has been performed on a practical ultra high-performance liquid chromatography (UHPLC), diode array detection (DAD), and tandem mass spectrometry (MS) method for determination of yohimbine in yohimbe barks and related dietary supplements. Good separation was achieved u...

Ink dating using thermal desorption and gas chromatography/mass spectrometry: comparison of results obtained in two laboratories.

PubMed

Koenig, Agnès; Bügler, Jürgen; Kirsch, Dieter; Köhler, Fritz; Weyermann, Céline

2015-01-01

An ink dating method based on solvent analysis was recently developed using thermal desorption followed by gas chromatography/mass spectrometry (GC/MS) and is currently implemented in several forensic laboratories. The main aims of this work were to implement this method in a new laboratory to evaluate whether results were comparable at three levels: (i) validation criteria, (ii) aging curves, and (iii) results interpretation. While the results were indeed comparable in terms of validation, the method proved to be very sensitive to maintenances. Moreover, the aging curves were influenced by ink composition, as well as storage conditions (particularly when the samples were not stored in "normal" room conditions). Finally, as current interpretation models showed limitations, an alternative model based on slope calculation was proposed. However, in the future, a probabilistic approach may represent a better solution to deal with ink sample inhomogeneity. © 2014 American Academy of Forensic Science.

Identification and quantification of nitrofurazone metabolites by ultraperformance liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry with precolumn derivatization.

PubMed

Zhang, Shuai; Li, PeiPei; Yan, Zhongyong; Long, Ju; Zhang, Xiaojun

2017-03-01

An ultraperformance liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry method was developed and validated for the determination of nitrofurazone metabolites. Precolumn derivatization with 2,4-dinitrophenylhydrazine and p-dimethylaminobenzaldehyde as an internal standard was used successfully to determine the biomarker 5-nitro-2-furaldehyde. In negative electrospray ionization mode, the precise molecular weights of the derivatives were 320.0372 for the biomarker and 328.1060 for the internal standard (relative error 1.08 ppm). The matrix effect was evaluated and the analytical characteristics of the method and derivatization reaction conditions were validated. For comparison purposes, spiked samples were tested by both internal and external standard methods. The results show high precision can be obtained with p-dimethylaminobenzaldehyde as an internal standard for the identification and quantification of nitrofurazone metabolites in complex biological samples. Graphical Abstract A simplified preparation strategy for biological samples.

Guilty by dissociation-development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 13 diphenidine-derived new psychoactive substances (NPSs).

PubMed

Geyer, Pierre M; Hulme, Matthew C; Irving, Joseph P B; Thompson, Paul D; Ashton, Ryan N; Lee, Robert J; Johnson, Lucy; Marron, Jack; Banks, Craig E; Sutcliffe, Oliver B

2016-11-01

The prevalence of new psychoactive substances (NPSs) in forensic casework has increased prominently in recent years. This has given rise to significant legal and analytical challenges in the identification of these substances. The requirement for validated, robust and rapid testing methodologies for these compounds is obvious. This study details the analysis of 13 synthesised diphenidine derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS). Specifically, the validated GC-MS method provides, for the first time, both a general screening method and quantification of the active components for seized solid samples, both in their pure form and in the presence of common adulterants. Graphical Abstract Chemical synthesis and forensic analysis of 13 diphenidine-derived new psychoactive substance(s).

Validation and use of three complementary analytical methods (LC-FLS, LC-MS/MS and ICP-MS) to evaluate the pharmacokinetics, biodistribution and stability of motexafin gadolinium in plasma and tissues.

PubMed

Miles, Dale R; Mesfin, Mimi; Mody, Tarak D; Stiles, Mark; Lee, Jean; Fiene, John; Denis, Bernie; Boswell, Garry W

2006-05-01

Liquid chromatography-fluorescence (LC-FLS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma-mass spectrometry (ICP-MS) methods were developed and validated for the evaluation of motexafin gadolinium (MGd, Xcytrin) pharmacokinetics and biodistribution in plasma and tissues. The LC-FLS method exhibited the greatest sensitivity (0.0057 microg mL(-1)), and was used for pharmacokinetic, biodistribution, and protein binding studies with small sample sizes or low MGd concentrations. The LC-MS/MS method, which exhibited a short run time and excellent selectivity, was used for routine clinical plasma sample analysis. The ICP-MS method, which measured total Gd, was used in conjunction with LC methods to assess MGd stability in plasma. All three methods were validated using human plasma. The LC-FLS method was also validated using plasma, liver and kidneys from mice and rats. All three methods were shown to be accurate, precise and robust for each matrix validated. For three mice, the mean (standard deviation) concentration of MGd in plasma/tissues taken 5 hr after dosing with 23 mg kg(-1) MGd was determined by LC-FLS as follows: plasma (0.025+/-0.002 microg mL(-1)), liver (2.89+/-0.45 microg g(-1)), and kidney (6.09+/-1.05 microg g(-1)). Plasma samples from a subset of patients with brain metastases from extracranial tumors were analyzed using both LC-MS/MS and ICP-MS methods. For a representative patient, > or = 90% of the total Gd in plasma was accounted for as MGd over the first hour post dosing. By 24 hr post dosing, 63% of total Gd was accounted for as MGd, indicating some metabolism of MGd.

Validation of a confirmatory method for the determination of residues of four nitrofurans in egg by liquid chromatography-tandem mass spectrometry with the software InterVal.

PubMed

Bock, C; Stachel, C; Gowik, P

2007-03-14

A method for the detection and determination of nitrofuran derivatives in egg by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was validated with the software InterVal and can be applied for the confirmation of nitrofuran metabolites in fresh or lyophilised eggs. The validation study comprises variations in operator, storage condition, breeding, equipment and duration of sample preparation. A comprehensive overview of the robustness of the method is obtained by analysing eight samples at six concentration levels. First results of short- and medium-term investigations for stability of analytes in solution show that standard solutions of nitrofuran metabolites are stable for at least 1 year when stored at +4 degrees C in the dark. The decision limit CCalpha expressed for the underivatised metabolite is 0.05 microg kg(-1) for 3-amino-5-methyl-morpholino-2-oxazolidinone, 0.03 microg kg(-1) for 3-amino-2-oxazolidinone, 0.20 microg kg(-1) for semicarbazide and 0.22 microg kg(-1) for 1-amino-hydantoin.

Multiresidue analysis of 22 sulfonamides and their metabolites in animal tissues using quick, easy, cheap, effective, rugged, and safe extraction and high resolution mass spectrometry (hybrid linear ion trap-Orbitrap).

PubMed

Abdallah, H; Arnaudguilhem, C; Jaber, F; Lobinski, R

2014-08-15

A new high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) method was developed for a simultaneous multi-residue analysis of 22 sulfonamides (SAs) and their metabolites in edible animal (pig, beef, sheep and chicken) tissues. Sample preparation was optimized on the basis of the "QuEChERS" protocol. The analytes were identified using their LC retention times and accurate mass; the identification was further confirmed by multi-stage high mass accuracy (<5ppm) mass spectrometry. The performance of the method was evaluated according to the EU guidelines for the validation of screening methods for the analysis of veterinary drugs residues. Acceptable values were obtained for: linearity (R(2)<0.99), limit of detection (LOD, 3-26μg/kg), limit of quantification (LOQ, 11-88μg/kg), accuracy (recovery 88-112%), intra- and inter-day precision 1-14 and 1-17%, respectively, decision limit (CCα) and detection capability (CCβ) around the maximum residue limits (MRL) of SAs (100μg/kg). The method was validated by analysis of a reference material FAPAS-02188 "Pig kidney" with ǀ Z-scoreǀ<0.63. The method was applied to various matrices (kidney, liver, muscle) originated from pig, beef, sheep, and chicken) allowing the simultaneous quantification of target sulfonamides at concentration levels above the MRL/2 and the identification of untargeted compounds such as N(4)-acetyl metabolites using multi-stage high mass accuracy mass spectrometry. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of inductively coupled plasma sector field mass spectrometry for low-level environmental americium-241 analysis.

PubMed

Varga, Zsolt

2007-03-28

An improved and novel sample preparation method for (241)Am analysis by inductively coupled plasma sector field mass spectrometry has been developed. The procedure involves a selective CaF(2) pre-concentration followed by an extraction chromatographic separation using TRU resin. The achieved absolute detection limit of 0.86 fg (0.11 mBq) is comparable to that of alpha spectrometry (0.1 mBq) and suitable for low-level environmental measurements. Analysis of different kinds of environmental standard reference materials (IAEA-384--Fangataufa lagoon sediment, IAEA-385--Irish Sea sediment and IAEA-308--Mixed seaweed from the Mediterranean Sea) and alpha spectrometry were used to validate the procedure. The chemical recovery of sample preparation ranged between 72 and 94%. The results obtained are in good agreement with reference values and those measured by alpha spectrometry. The proposed method offers a rapid and less labor-intensive possibility for environmental (241)Am analysis than the conventionally applied radioanalytical techniques.

Simultaneous determination of 5'-monophosphate nucleotides in infant formulas by HPLC-MS.

PubMed

Ren, Yiping; Zhang, Jingshun; Song, Xiaodan; Chen, Xiaochun; Li, Duo

2011-04-01

A method was developed for simultaneous determination of 5'-monophosphate nucleotides, adenosine 5'-monophosphate, cytidine 5'-monophosphate, guanosine 5'-monophosphate, inosine 5'-monophosphate, and uridine 5'-monophosphate in infant formulas by high-performance liquid chromatography-mass spectrometry equipped with electrospray ionization source. The complete chromatographic separation of five nucleotides was achieved through a Symmetry C(18) column, after a binary gradient elution with water containing 0.1% formic acid and acetonitrile as mobile phase. The multi-reaction monitoring mode was applied for tandem mass spectrometry analysis. The established method was further validated by determining the linearity (R(2) > 0.999), recovery (92.0-105.0%), and precision (relative standard deviation ≤6.97%). To verify the applicability of the method, thirty commercially available infant formulas were randomly purchased from the supermarkets in Hangzhou, China, and then analyzed. The results showed that the developed method is validated, sensitive, and reliable for quantitation of nucleotides in infant formulas.

Rapid and reliable quantitation of amino acids and myo-inositol in mouse brain by high performance liquid chromatography and tandem mass spectrometry.

PubMed

Bathena, Sai P; Huang, Jiangeng; Epstein, Adrian A; Gendelman, Howard E; Boska, Michael D; Alnouti, Yazen

2012-04-15

Amino acids and myo-inositol have long been proposed as putative biomarkers for neurodegenerative diseases. Accurate measures and stability have precluded their selective use. To this end, a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on multiple reaction monitoring was developed to simultaneously quantify glutamine, glutamate, γ-aminobutyric acid (GABA), aspartic acid, N-acetyl aspartic acid, taurine, choline, creatine, phosphocholine and myo-inositol in mouse brain by methanol extractions. Chromatography was performed using a hydrophilic interaction chromatography silica column within in a total run time of 15 min. The validated method is selective, sensitive, accurate, and precise. The method has a limit of quantification ranging from 2.5 to 20 ng/ml for a range of analytes and a dynamic range from 2.5-20 to 500-4000 ng/ml. This LC-MS/MS method was validated for biomarker discovery in models of human neurological disorders. Copyright © 2012 Elsevier B.V. All rights reserved.

Screening for trace explosives by AccuTOF™-DART®: an in-depth validation study.

PubMed

Sisco, Edward; Dake, Jeffrey; Bridge, Candice

2013-10-10

Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques [1]. This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Rapid extraction and determination of 25 bioactive constituents in Alpinia oxyphylla using microwave extraction with ultra high performance liquid chromatography with tandem mass spectrometry.

PubMed

Sun, Zhi; Kong, Xiangzhen; Zuo, Lihua; Kang, Jian; Hou, Lei; Zhang, Xiaojian

2016-02-01

A novel and rapid microwave extraction and ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of 25 bioactive constituents (including two new constituents) in Fructus Alpinia oxyphylla. The optimized conditions of the microwave extraction was a microwave power of 300 W, extraction temperature of 80°C, solvent-to-solid ratio of 30 mL/g and extraction time of 8 min. Separation was achieved on a Waters ACQUITY UPLC(®) HSS C18 column (2.1 mm× 50 mm, 1.8 μm) using gradient elution with a mobile phase consisting of acetonitrile and 1 mM ammonium acetate at a flow rate of 0.2 mL/min. This is the first report of the simultaneous determination of 25 bioactive constituents in Fructus Alpinia oxyphylla by ultra high performance liquid chromatography with tandem mass spectrometry. The method was validated with good linearity, acceptable precision and accuracy. The validated method was successfully applied to determine the contents of 25 bioactive constituents in Fructus Alpinia oxyphylla from different sources and the analysis results were classified by hierarchical cluster analysis, which indicated the effect of different cultivation regions on the contents of constituents. This study provides powerful and practical guidance in the quality control of Alpinia oxyphylla and lays the foundation for further research of Alpinia oxyphylla. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of a liquid chromatography-tandem mass spectrometry method for the identification and quantification of 5-nitroimidazole drugs and their corresponding hydroxy metabolites in lyophilised pork meat.

PubMed

Zeleny, Reinhard; Harbeck, Stefan; Schimmel, Heinz

2009-01-09

A liquid chromatography-electrospray ionisation tandem mass spectrometry method for the simultaneous detection and quantitation of 5-nitroimidazole veterinary drugs in lyophilised pork meat, the chosen format of a candidate certified reference material, has been developed and validated. Six analytes have been included in the scope of validation, i.e. dimetridazole (DMZ), metronidazole (MNZ), ronidazole (RNZ), hydroxymetronidazole (MNZOH), hydroxyipronidazole (IPZOH), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI). The analytes were extracted from the sample with ethyl acetate, chromatographically separated on a C(18) column, and finally identified and quantified by tandem mass spectrometry in the multiple reaction monitoring mode (MRM) using matrix-matched calibration and (2)H(3)-labelled analogues of the analytes (except for MNZOH, where [(2)H(3)]MNZ was used). The method was validated in accordance with Commission Decision 2002/657/EC, by determining selectivity, linearity, matrix effect, apparent recovery, repeatability and intermediate precision, decision limits and detection capabilities, robustness of sample preparation method, and stability of extracts. Recovery at 1 microg/kg level was at 100% (estimates in the range of 101-107%) for all analytes, repeatabilities and intermediate precisions at this level were in the range of 4-12% and 2-9%, respectively. Linearity of calibration curves in the working range 0.5-10 microg/kg was confirmed, with r values typically >0.99. Decision limits (CCalpha) and detection capabilities (CCbeta) according to ISO 11843-2 (calibration curve approach) were 0.29-0.44 and 0.36-0.54 microg/kg, respectively. The method reliably identifies and quantifies the selected nitroimidazoles in the reconstituted pork meat in the low and sub-microg/kg range and will be applied in an interlaboratory comparison for determining the mass fraction of the selected nitroimidazoles in the candidate reference material currently developed at IRMM.

Validation and long-term evaluation of a modified on-line chiral analytical method for therapeutic drug monitoring of (R,S)-methadone in clinical samples.

PubMed

Ansermot, Nicolas; Rudaz, Serge; Brawand-Amey, Marlyse; Fleury-Souverain, Sandrine; Veuthey, Jean-Luc; Eap, Chin B

2009-08-01

Matrix effects, which represent an important issue in liquid chromatography coupled to mass spectrometry or tandem mass spectrometry detection, should be closely assessed during method development. In the case of quantitative analysis, the use of stable isotope-labelled internal standard with physico-chemical properties and ionization behaviour similar to the analyte is recommended. In this paper, an example of the choice of a co-eluting deuterated internal standard to compensate for short-term and long-term matrix effect in the case of chiral (R,S)-methadone plasma quantification is reported. The method was fully validated over a concentration range of 5-800 ng/mL for each methadone enantiomer with satisfactory relative bias (-1.0 to 1.0%), repeatability (0.9-4.9%) and intermediate precision (1.4-12.0%). From the results obtained during validation, a control chart process during 52 series of routine analysis was established using both intermediate precision standard deviation and FDA acceptance criteria. The results of routine quality control samples were generally included in the +/-15% variability around the target value and mainly in the two standard deviation interval illustrating the long-term stability of the method. The intermediate precision variability estimated in method validation was found to be coherent with the routine use of the method. During this period, 257 trough concentration and 54 peak concentration plasma samples of patients undergoing (R,S)-methadone treatment were successfully analysed for routine therapeutic drug monitoring.

Development of a multiresidue method for the determination of endocrine disrupters in fish fillet using gas chromatography-triple quadrupole tandem mass spectrometry.

PubMed

Munaretto, Juliana S; Ferronato, Giovana; Ribeiro, Lucila C; Martins, Manoel L; Adaime, Martha B; Zanella, Renato

2013-11-15

Endocrine Disrupter Compounds (EDCs) are responsible for alterations in the endocrine system functions. Aquatic organisms are able to accumulate EDCs residues, being the major source of contamination for top predators and human consumers. This study aimed to develop and validate a method for the determination of 40 EDCs in fish fillet using modified QuEChERS and Gas Chromatography coupled with Mass Spectrometry in tandem (GC-MS/MS). A factorial design was used to optimize the extraction procedure. Method validation presented recoveries from 70.1% to 120.0% with RSD<20% and method limit of detection ranged from 0.3 to 7.5 µg kg(-1), showing good accuracy and precision. This method was successfully applied to the analysis of fish fillet from different species and residues of bisphenol A, chlorpyrifos and bifenthrin were detected. The proposed method proved to be effective for the determination of EDCs in fish fillet at very low concentration levels. © 2013 Elsevier B.V. All rights reserved.

Development and validation of rapid multiresidue and multi-class analysis for antibiotics and anthelmintics in feed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry.

PubMed

Robert, Christelle; Brasseur, Pierre-Yves; Dubois, Michel; Delahaut, Philippe; Gillard, Nathalie

2016-08-01

A new multi-residue method for the analysis of veterinary drugs, namely amoxicillin, chlortetracycline, colistins A and B, doxycycline, fenbendazole, flubendazole, ivermectin, lincomycin, oxytetracycline, sulfadiazine, tiamulin, tilmicosin and trimethoprim, was developed and validated for feed. After acidic extraction, the samples were centrifuged, purified by SPE and analysed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/CE. Matrix-matched calibration with internal standards was used to reduce matrix effects. The target level was set at the authorised carryover level (1%) and validation levels were set at 0.5%, 1% and 1.5%. Method performances were evaluated by the following parameters: linearity (0.986 < R(2) < 0.999), precision (repeatability < 12.4% and reproducibility < 14.0%), accuracy (89% < recovery < 107%), sensitivity, decision limit (CCα), detection capability (CCβ), selectivity and expanded measurement uncertainty (k = 2).This method has been used successfully for three years for routine monitoring of antibiotic residues in feeds during which period 20% of samples were found to exceed the 1% authorised carryover limit and were deemed non-compliant.

Application of High-Performance Liquid Chromatography Coupled with Linear Ion Trap Quadrupole Orbitrap Mass Spectrometry for Qualitative and Quantitative Assessment of Shejin-Liyan Granule Supplements.

PubMed

Gu, Jifeng; Wu, Weijun; Huang, Mengwei; Long, Fen; Liu, Xinhua; Zhu, Yizhun

2018-04-11

A method for high-performance liquid chromatography coupled with linear ion trap quadrupole Orbitrap high-resolution mass spectrometry (HPLC-LTQ-Orbitrap MS) was developed and validated for the qualitative and quantitative assessment of Shejin-liyan Granule. According to the fragmentation mechanism and high-resolution MS data, 54 compounds, including fourteen isoflavones, eleven ligands, eight flavonoids, six physalins, six organic acids, four triterpenoid saponins, two xanthones, two alkaloids, and one licorice coumarin, were identified or tentatively characterized. In addition, ten of the representative compounds (matrine, galuteolin, tectoridin, iridin, arctiin, tectorigenin, glycyrrhizic acid, irigenin, arctigenin, and irisflorentin) were quantified using the validated HPLC-LTQ-Orbitrap MS method. The method validation showed a good linearity with coefficients of determination (r²) above 0.9914 for all analytes. The accuracy of the intra- and inter-day variation of the investigated compounds was 95.0-105.0%, and the precision values were less than 4.89%. The mean recoveries and reproducibilities of each analyte were 95.1-104.8%, with relative standard deviations below 4.91%. The method successfully quantified the ten compounds in Shejin-liyan Granule, and the results show that the method is accurate, sensitive, and reliable.

Monitoring of platinum surface contamination in seven Dutch hospital pharmacies using inductively coupled plasma mass spectrometry

PubMed Central

Huitema, A. D. R.; Bakker, E. N.; Douma, J. W.; Schimmel, K. J. M.; van Weringh, G.; de Wolf, P. J.; Schellens, J. H. M.; Beijnen, J. H.

2007-01-01

Objective: To develop, validate, and apply a method for the determination of platinum contamination, originating from cisplatinum, oxaliplatinum, and carboplatinum. Methods: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine platinum in wipe samples. The sampling procedure and the analytical conditions were optimised and the assay was validated. The method was applied to measure surface contamination in seven Dutch hospital pharmacies. Results: The developed method allowed reproducible quantification of 0.50 ng l−1 platinum (5 pg/wipe sample). Recoveries for stainless steel and linoleum surfaces ranged between 50.4 and 81.4% for the different platinum compounds tested. Platinum contamination was reported in 88% of the wipe samples. Although a substantial variation in surface contamination of the pharmacies was noticed, in most pharmacies, the laminar-airflow (LAF) hoods, the floor in front of the LAF hoods, door handles, and handles of service hatches showed positive results. This demonstrates that contamination is spread throughout the preparation rooms. Conclusion: We developed and validated an ultra sensitive and reliable ICP-MS method for the determination of platinum in surface samples. Surface contamination with platinum was observed in all hospital pharmacies sampled. The interpretation of these results is, however, complicated. PMID:17377802

Determination of anthelmintic drug residues in milk using ultra high performance liquid chromatography-tandem mass spectrometry with rapid polarity switching.

PubMed

Whelan, Michelle; Kinsella, Brian; Furey, Ambrose; Moloney, Mary; Cantwell, Helen; Lehotay, Steven J; Danaher, Martin

2010-07-02

A new UHPLC-MS/MS (ultra high performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added concentration step to detect most of the analytes at <1 microg kg(-1) levels in milk. Anthelmintic residues were extracted into acetonitrile using magnesium sulphate and sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure analytes remain in solution. Using rapid polarity switching in electrospray ionisation, a single injection was capable of detecting both positively and negatively charged ions in a 13 min run time. The method was validated at two levels: the unapproved use level and at the maximum residue level (MRL) according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCalpha) of the method was in the range of 0.14-1.9 and 11-123 microg kg(-1) for drugs validated at unapproved and MRL levels, respectively. The performance of the method was successfully verified for benzimidazoles and levamisole by participating in a proficiency study.

Validation of highly sensitive simultaneous targeted and untargeted analysis of keto-steroids by Girard P derivatization and stable isotope dilution-liquid chromatography-high resolution mass spectrometry.

PubMed

Frey, Alexander J; Wang, Qingqing; Busch, Christine; Feldman, Daniel; Bottalico, Lisa; Mesaros, Clementina A; Blair, Ian A; Vachani, Anil; Snyder, Nathaniel W

2016-12-01

A multiplexed quantitative method for the analysis of three major unconjugated steroids in human serum by stable isotope dilution liquid chromatography-high resolution mass spectrometry (LC-HRMS) was developed and validated on a Q Exactive Plus hybrid quadrupole/Orbitrap mass spectrometer. This quantification utilized isotope dilution and Girard P derivatization on the keto-groups of testosterone (T), androstenedione (AD) and dehydroepiandrosterone (DHEA) to improve ionization efficiency using electrospray ionization. Major isomeric compounds to T and DHEA; the inactive epimer of testosterone (epiT), and the metabolite of AD, 5α-androstanedione (5α-AD) were completely resolved on a biphenyl column within an 18min method. Inter- and intra-day method validation using LC-HRMS with qualifying product ions was performed and acceptable analytical performance was achieved. The method was further validated by comparing steroid levels from 100μL of serum from young vs older subjects. Since this approach provides high-dimensional HRMS data, untargeted analysis by age group was performed. DHEA and T were detected among the top analytes most significantly different across the two groups after untargeted LC-HRMS analysis, as well as a number of other still unknown metabolites, indicating the potential for combined targeted/untargeted analysis in steroid analysis. Copyright © 2016 Elsevier Inc. All rights reserved.

Multicenter validation of the VITEK MS v2.0 MALDI-TOF mass spectrometry system for the identification of fastidious gram-negative bacteria.

PubMed

Branda, John A; Rychert, Jenna; Burnham, Carey-Ann D; Bythrow, Maureen; Garner, Omai B; Ginocchio, Christine C; Jennemann, Rebecca; Lewinski, Michael A; Manji, Ryhana; Mochon, A Brian; Procop, Gary W; Richter, Sandra S; Sercia, Linda F; Westblade, Lars F; Ferraro, Mary Jane

2014-02-01

The VITEK MS v2.0 MALDI-TOF mass spectrometry system's performance in identifying fastidious gram-negative bacteria was evaluated in a multicenter study. Compared with the reference method (DNA sequencing), the VITEK MS system provided an accurate, species-level identification for 96% of 226 isolates; an additional 1% were accurately identified to the genus level. © 2013.

Rapid determination of phenolic compounds and alkaloids of carob flour by improved liquid chromatography tandem mass spectrometry.

PubMed

Ortega, Nàdia; Macià, Alba; Romero, Maria-Paz; Trullols, Esther; Morello, Jose-Ramón; Anglès, Neus; Motilva, Maria-Jose

2009-08-26

An improved chromatographic method was developed using ultra-performance liquid chromatography-tandem mass spectrometry to identify and quantify phenolic compounds and alkaloids, theobromine and caffeine, in carob flour samples. The developed method has been validated in terms of speed, sensitivity, selectivity, peak efficiency, linearity, reproducibility, limits of detection, and limits of quantification. The chromatographic method allows the identification and quantification of 20 phenolic compounds, that is, phenolic acids, flavonoids, and their aglycone and glucoside forms, together with the determination of the alkaloids, caffeine and theobromine, at low concentration levels all in a short analysis time of less than 20 min.

Determination of glycerol in oils and fats using liquid chromatography chloride attachment electrospray ionization mass spectrometry.

PubMed

Jin, Chunfen; Viidanoja, Jyrki

2017-01-15

Existing liquid chromatography - mass spectrometry method for the analysis of short chain carboxylic acids was expanded and validated to cover also the measurement of glycerol from oils and fats. The method employs chloride anion attachment and two ions, [glycerol+ 35 Cl] - and [glycerol+ 37 Cl] - , as alternative quantifiers for improved selectivity of glycerol measurement. The averaged within run precision, between run precision and accuracy ranged between 0.3-7%, 0.4-6% and 94-99%, respectively, depending on the analyte ion and sample matrix. Selected renewable diesel feedstocks were analyzed with the method. Copyright © 2016 Elsevier B.V. All rights reserved.

Comprehensive evaluation of direct injection mass spectrometry for the quantitative profiling of volatiles in food samples

PubMed Central

2016-01-01

Although qualitative strategies based on direct injection mass spectrometry (DIMS) have recently emerged as an alternative for the rapid classification of food samples, the potential of these approaches in quantitative tasks has scarcely been addressed to date. In this paper, the applicability of different multivariate regression procedures to data collected by DIMS from simulated mixtures has been evaluated. The most relevant factors affecting quantitation, such as random noise, the number of calibration samples, type of validation, mixture complexity and similarity of mass spectra, were also considered and comprehensively discussed. Based on the conclusions drawn from simulated data, and as an example of application, experimental mass spectral fingerprints collected by direct thermal desorption coupled to mass spectrometry were used for the quantitation of major volatiles in Thymus zygis subsp. zygis chemotypes. The results obtained, validated with the direct thermal desorption coupled to gas chromatography–mass spectrometry method here used as a reference, show the potential of DIMS approaches for the fast and precise quantitative profiling of volatiles in foods. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644978

Determination of glucosinolates in rapeseed and Thlaspi caerulescens plants by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

PubMed

Tolrà, R P; Alonso, R; Poschenrieder, C; Barceló, D; Barceló, J

2000-08-11

Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry was used to identify glucosinolates in plant extracts. Optimization of the analytical conditions and the determination of the method detection limit was performed using commercial 2-propenylglucosinolate (sinigrin). Optimal values for the following parameters were determined: nebulization pressure, gas temperature, flux of drying gas, capillar voltage, corona current and fragmentor conditions. The method detection limit for sinigrin was 2.85 ng. For validation of the method the glucosinolates in reference material (rapeseed) from the Community Bureau of Reference Materials (BCR) were analyzed. The method was applied for the determination of glucosinolates in Thlaspi caerulescens plants.

Quantification of endocrine disruptors and pesticides in water by gas chromatography-tandem mass spectrometry. Method validation using weighted linear regression schemes.

PubMed

Mansilha, C; Melo, A; Rebelo, H; Ferreira, I M P L V O; Pinho, O; Domingues, V; Pinho, C; Gameiro, P

2010-10-22

A multi-residue methodology based on a solid phase extraction followed by gas chromatography-tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC-MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness. Copyright © 2010 Elsevier B.V. All rights reserved.

Determination of anthelmintic drug residues in milk using UPLC-MS/MS with rapid polarity switching

USDA-ARS?s Scientific Manuscript database

A new UPLC-MS/MS (ultra-performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added...

The combination of four analytical methods to explore skeletal muscle metabolomics: Better coverage of metabolic pathways or a marketing argument?

PubMed

Bruno, C; Patin, F; Bocca, C; Nadal-Desbarats, L; Bonnier, F; Reynier, P; Emond, P; Vourc'h, P; Joseph-Delafont, K; Corcia, P; Andres, C R; Blasco, H

2018-01-30

Metabolomics is an emerging science based on diverse high throughput methods that are rapidly evolving to improve metabolic coverage of biological fluids and tissues. Technical progress has led researchers to combine several analytical methods without reporting the impact on metabolic coverage of such a strategy. The objective of our study was to develop and validate several analytical techniques (mass spectrometry coupled to gas or liquid chromatography and nuclear magnetic resonance) for the metabolomic analysis of small muscle samples and evaluate the impact of combining methods for more exhaustive metabolite covering. We evaluated the muscle metabolome from the same pool of mouse muscle samples after 2 metabolite extraction protocols. Four analytical methods were used: targeted flow injection analysis coupled with mass spectrometry (FIA-MS/MS), gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), and nuclear magnetic resonance (NMR) analysis. We evaluated the global variability of each compound i.e., analytical (from quality controls) and extraction variability (from muscle extracts). We determined the best extraction method and we reported the common and distinct metabolites identified based on the number and identity of the compounds detected with low analytical variability (variation coefficient<30%) for each method. Finally, we assessed the coverage of muscle metabolic pathways obtained. Methanol/chloroform/water and water/methanol were the best extraction solvent for muscle metabolome analysis by NMR and MS, respectively. We identified 38 metabolites by nuclear magnetic resonance, 37 by FIA-MS/MS, 18 by GC-MS, and 80 by LC-HRMS. The combination led us to identify a total of 132 metabolites with low variability partitioned into 58 metabolic pathways, such as amino acid, nitrogen, purine, and pyrimidine metabolism, and the citric acid cycle. This combination also showed that the contribution of GC-MS was low when used in combination with other mass spectrometry methods and nuclear magnetic resonance to explore muscle samples. This study reports the validation of several analytical methods, based on nuclear magnetic resonance and several mass spectrometry methods, to explore the muscle metabolome from a small amount of tissue, comparable to that obtained during a clinical trial. The combination of several techniques may be relevant for the exploration of muscle metabolism, with acceptable analytical variability and overlap between methods However, the difficult and time-consuming data pre-processing, processing, and statistical analysis steps do not justify systematically combining analytical methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Development and validation of a sensitive thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method for the determination of phosgene in air samples.

PubMed

Juillet, Y; Dubois, C; Bintein, F; Dissard, J; Bossée, A

2014-08-01

A new rapid, sensitive and reliable method was developed for the determination of phosgene in air samples using thermal desorption (TD) followed by gas chromatography-mass spectrometry (GC-MS). The method is based on a fast (10 min) active sampling of only 1 L of air onto a Tenax® GR tube doped with 0.5 mL of derivatizing mixture containing dimercaptotoluene and triethylamine in hexane solution. Validation of the TD-GC-MS method showed a low limit of detection (40 ppbv), acceptable repeatability, intermediate fidelity (relative standard deviation within 12 %) and excellent accuracy (>95%). Linearity was demonstrated for two concentration ranges (0.04 to 2.5 ppmv and 2.5 to 10 ppmv) owing to variation of derivatization recovery between low and high concentration levels. Due to its simple on-site implementation and its close similarity with recommended operating procedure (ROP) for chemical warfare agents vapour sampling, the method is particularly useful in the process of verification of the Chemical Weapons Convention.

Quantitative measurement of intact alpha-synuclein proteoforms from post-mortem control and Parkinson's disease brain tissue by intact protein mass spectrometry.

PubMed

Kellie, John F; Higgs, Richard E; Ryder, John W; Major, Anthony; Beach, Thomas G; Adler, Charles H; Merchant, Kalpana; Knierman, Michael D

2014-07-23

A robust top down proteomics method is presented for profiling alpha-synuclein species from autopsied human frontal cortex brain tissue from Parkinson's cases and controls. The method was used to test the hypothesis that pathology associated brain tissue will have a different profile of post-translationally modified alpha-synuclein than the control samples. Validation of the sample processing steps, mass spectrometry based measurements, and data processing steps were performed. The intact protein quantitation method features extraction and integration of m/z data from each charge state of a detected alpha-synuclein species and fitting of the data to a simple linear model which accounts for concentration and charge state variability. The quantitation method was validated with serial dilutions of intact protein standards. Using the method on the human brain samples, several previously unreported modifications in alpha-synuclein were identified. Low levels of phosphorylated alpha synuclein were detected in brain tissue fractions enriched for Lewy body pathology and were marginally significant between PD cases and controls (p = 0.03).

Ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of natural steroid hormones in sea lamprey (Petromyzon marinus) plasma and tissues.

PubMed

Wang, Huiyong; Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Weiming

2016-01-15

This study aims to provide a rapid, sensitive and precise UPLC-MS/MS method for target steroid quantitation in biological matrices. We developed and validated an UPLC-MS/MS method to simultaneously determine 16 steroids in plasma and tissue samples. Ionization sources of Electrospray Ionization (ESI) and Atmospheric Pressure Chemical Ionization (APCI) were compared in this study by testing their spectrometry performances at the same chromatographic conditions, and the ESI source was found up to five times more sensitive than the APCI. Different sample preparation techniques were investigated for an optimal extraction of steroids from the biological matrices. The developed method exhibited excellent linearity for all analytes with regression coefficients higher than 0.99 in broad concentration ranges. The limit of detection (LOD) was from 0.003 to 0.1ng/mL. The method was validated according to FDA guidance and applied to determine steroids in sea lamprey plasma and tissues (fat and testes) by the developed method. Copyright © 2015. Published by Elsevier B.V.

Validation of an optimized method for the determination of iodine in human breast milk by inductively coupled plasma mass spectrometry (ICPMS) after tetramethylammonium hydroxide extraction.

PubMed

Huynh, Dao; Zhou, Shao Jia; Gibson, Robert; Palmer, Lyndon; Muhlhausler, Beverly

2015-01-01

In this study a novel method to determine iodine concentrations in human breast milk was developed and validated. The iodine was analyzed by inductively coupled plasma mass spectrometry (ICPMS) following tetramethylammonium hydroxide (TMAH) extraction at 90°C in disposable polypropylene tubes. While similar approaches have been used previously, this method adopted a shorter extraction time (1h vs. 3h) and used antimony (Sb) as the internal standard, which exhibited greater stability in breast milk and milk powder matrices compared to tellurium (Te). Method validation included: defining iodine linearity up to 200μgL(-1); confirming recovery of iodine from NIST 1549 milk powder. A recovery of 94-98% was also achieved for the NIST 1549 milk powder and human breast milk samples spiked with sodium iodide and thyroxine (T4) solutions. The method quantitation limit (MQL) for human breast milk was 1.6μgL(-1). The intra-assay and inter-assay coefficient of variation for the breast milk samples and NIST powder were <1% and <3.5%, respectively. NIST 1549 milk powder, human breast milk samples and calibration standards spiked with the internal standard were all stable for at least 2.5 months after extraction. The results of the validation process confirmed that this newly developed method provides greater accuracy and precision in the assessment of iodine concentrations in human breast milk than previous methods and therefore offers a more reliable approach for assessing iodine concentrations in human breast milk. Copyright © 2014 Elsevier GmbH. All rights reserved.

Adulteration of diesel/biodiesel blends by vegetable oil as determined by Fourier transform (FT) near infrared spectrometry and FT-Raman spectroscopy.

PubMed

Oliveira, Flavia C C; Brandão, Christian R R; Ramalho, Hugo F; da Costa, Leonardo A F; Suarez, Paulo A Z; Rubim, Joel C

2007-03-28

In this work it has been shown that the routine ASTM methods (ASTM 4052, ASTM D 445, ASTM D 4737, ASTM D 93, and ASTM D 86) recommended by the ANP (the Brazilian National Agency for Petroleum, Natural Gas and Biofuels) to determine the quality of diesel/biodiesel blends are not suitable to prevent the adulteration of B2 or B5 blends with vegetable oils. Considering the previous and actual problems with fuel adulterations in Brazil, we have investigated the application of vibrational spectroscopy (Fourier transform (FT) near infrared spectrometry and FT-Raman) to identify adulterations of B2 and B5 blends with vegetable oils. Partial least square regression (PLS), principal component regression (PCR), and artificial neural network (ANN) calibration models were designed and their relative performances were evaluated by external validation using the F-test. The PCR, PLS, and ANN calibration models based on the Fourier transform (FT) near infrared spectrometry and FT-Raman spectroscopy were designed using 120 samples. Other 62 samples were used in the validation and external validation, for a total of 182 samples. The results have shown that among the designed calibration models, the ANN/FT-Raman presented the best accuracy (0.028%, w/w) for samples used in the external validation.

76 FR 55329 - Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or on Various...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-07

... (HPLC) method was validated for determination of dinotefuran, DN and UF in or on tomatoes and peppers... quantified after HPLC separation by tandem mass spectrometry (MS/MS) detection. Contact: Sidney Jackson, (703..., group 9 at 0.03 ppm. Adequate analytical methods (HPLC-fluorescence methods) are available for...

Novel Selectivity-Based Forensic Toxicological Validation of a Paper Spray Mass Spectrometry Method for the Quantitative Determination of Eight Amphetamines in Whole Blood.

PubMed

Teunissen, Sebastiaan F; Fedick, Patrick W; Berendsen, Bjorn J A; Nielen, Michel W F; Eberlin, Marcos N; Graham Cooks, R; van Asten, Arian C

2017-12-01

Paper spray tandem mass spectrometry is used to identify and quantify eight individual amphetamines in whole blood in 1.3 min. The method has been optimized and fully validated according to forensic toxicology guidelines, for the quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), and 4-fluoroamphetamine (4-FA). Additionally, a new concept of intrinsic and application-based selectivity is discussed, featuring increased confidence in the power to discriminate the amphetamines from other chemically similar compounds when applying an ambient mass spectrometric method without chromatographic separation. Accuracy was within ±15% and average precision was better than 15%, and better than 20% at the LLOQ. Detection limits between 15 and 50 ng/mL were obtained using only 12 μL of whole blood. Graphical abstract ᅟ.

Novel Selectivity-Based Forensic Toxicological Validation of a Paper Spray Mass Spectrometry Method for the Quantitative Determination of Eight Amphetamines in Whole Blood

NASA Astrophysics Data System (ADS)

Teunissen, Sebastiaan F.; Fedick, Patrick W.; Berendsen, Bjorn J. A.; Nielen, Michel W. F.; Eberlin, Marcos N.; Graham Cooks, R.; van Asten, Arian C.

2017-12-01

Paper spray tandem mass spectrometry is used to identify and quantify eight individual amphetamines in whole blood in 1.3 min. The method has been optimized and fully validated according to forensic toxicology guidelines, for the quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy- N-methylamphetamine (MDMA), 3,4-methylenedioxy- N-ethylamphetamine (MDEA), para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), and 4-fluoroamphetamine (4-FA). Additionally, a new concept of intrinsic and application-based selectivity is discussed, featuring increased confidence in the power to discriminate the amphetamines from other chemically similar compounds when applying an ambient mass spectrometric method without chromatographic separation. Accuracy was within ±15% and average precision was better than 15%, and better than 20% at the LLOQ. Detection limits between 15 and 50 ng/mL were obtained using only 12 μL of whole blood. [Figure not available: see fulltext.

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. Copyright © 2016 Elsevier B.V. All rights reserved.

A multiresidue approach for the simultaneous quantification of antibiotics in macroalgae by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Leston, Sara; Freitas, Andreia; Rosa, João; Barbosa, Jorge; Lemos, Marco F L; Pardal, Miguel Ângelo; Ramos, Fernando

2016-10-15

Together with fish, algae reared in aquaculture systems have gained importance in the last years, for many purposes. Besides their use as biofilters of effluents, macroalgae's rich nutritional profiles have increased their inclusion in human diets but also in animal feeds as sources of fatty acids, especially important for the fish industry. Nonetheless, algae are continuously exposed to environmental contaminants including antibiotics and possess the ability for bioaccumulation of such compounds. Therefore, the present paper describes the development and validation of an ultra-high performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of antibiotics in the green macroalgae Ulva lactuca. This multi-residue method enables the determination of 38 compounds distributed between seven classes and was fully validated according to EU Decision 2002/657/EC. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous quantification of 25 active constituents in the total flavonoids extract from Herba Desmodii Styracifolii by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Guo, Panpan; Yan, Wenying; Han, Qingjie; Wang, Chunying; Zhang, Zijian

2015-04-01

A sensitive and selective high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous determination of 25 active constituents, including 21 flavonoids and four phenolic acids in the total flavonoids extract from Herba Desmodii Styracifolii for the first time. Among the 25 compounds, seven compounds including caffeic acid, acacetin, genistein, genistin, diosmetin, diosmin and hesperidin were identified and quantified for the first time in Herba Desmodii Styracifolii. Chromatographic separation was accomplished on a ZORBAX SB-C18 (250 mm×4.6 mm, 5.0 μm) column using gradient elution of methanol and 0.1‰ acetic acid v/v at a flow rate of 1.0 mL/min. The identification and quantification of the analytes were achieved using negative electrospray ionization mass spectrometry in multiple-reaction monitoring mode. The method was fully validated in terms of limits of detection and quantification, linearity, precision and accuracy. The results indicated that the developed method is simple, rapid, specific and reliable. Furthermore, the developed method was successfully applied to quantify the 25 active components in six batches of total flavonoids extract from Herba Desmodii Styracifolii. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of Validated Bioanalytical HPLC-UV Method for Simultaneous Estimation of Amlodipine and Atorvastatin in Rat Plasma

PubMed Central

Talele, G. S.; Porwal, P. K.

2015-01-01

A simple, economical and robust analytical high-performance liquid chromatography-ultraviolet method was developed and validated for simultaneous chromatographic elution of two cardiovascular drugs viz. amlodipine and atorvastatin in biological fluid for the first time. Only two liquid chromatography–mass spectrometry/mass spectrometry methods are available in literature for quantitation of selected pair of analytes. The bioanalytical method was developed in rat plasma by using Thermo beta-basic C18 (100×4.6 mm, 5 μm) and mobile phase was composed of dibasic phosphate buffer (pH 3.0):acetonitrile in the ratio of 55:45 at a flow rate of 1 ml/min with ultraviolet detection monitored at 240 nm. The selected chromatographic conditions were found to effectively separate amlodipine (5.1 min) and atorvastatin (12.1 min). The parametric statistics,i.e. correlation coefficient of 0.999, was assessed for both the drugs having linearity over the tested concentration range (0.05 to 10.0 μg/ml) in rat plasma using an unweighted calibration curve. The mean recovery (%) was more than 92.8% for both the drugs using protein precipitation method. The accuracy of samples for six replicate measurements at lower limit of quantitation level was within limit. The method was validated and was successfully applied to the nonclinical pharmacokinetic study of combination tablets containing amlodipine and atorvastatin in six Sprague Dawley rats. PMID:26997703

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for direct bacterial identification from positive blood culture pellets.

PubMed

Prod'hom, Guy; Bizzini, Alain; Durussel, Christian; Bille, Jacques; Greub, Gilbert

2010-04-01

An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested. Moreover, 99% of the MALDI-TOF identifications were congruent at the species level when considering valid scores. This fast and accurate method is promising.

Application of Multivariable Analysis and FTIR-ATR Spectroscopy to the Prediction of Properties in Campeche Honey

PubMed Central

Pat, Lucio; Ali, Bassam; Guerrero, Armando; Córdova, Atl V.; Garduza, José P.

2016-01-01

Attenuated total reflectance-Fourier transform infrared spectrometry and chemometrics model was used for determination of physicochemical properties (pH, redox potential, free acidity, electrical conductivity, moisture, total soluble solids (TSS), ash, and HMF) in honey samples. The reference values of 189 honey samples of different botanical origin were determined using Association Official Analytical Chemists, (AOAC), 1990; Codex Alimentarius, 2001, International Honey Commission, 2002, methods. Multivariate calibration models were built using partial least squares (PLS) for the measurands studied. The developed models were validated using cross-validation and external validation; several statistical parameters were obtained to determine the robustness of the calibration models: (PCs) optimum number of components principal, (SECV) standard error of cross-validation, (R 2 cal) coefficient of determination of cross-validation, (SEP) standard error of validation, and (R 2 val) coefficient of determination for external validation and coefficient of variation (CV). The prediction accuracy for pH, redox potential, electrical conductivity, moisture, TSS, and ash was good, while for free acidity and HMF it was poor. The results demonstrate that attenuated total reflectance-Fourier transform infrared spectrometry is a valuable, rapid, and nondestructive tool for the quantification of physicochemical properties of honey. PMID:28070445

Determination of sulfonamide antibiotics and metabolites in liver, muscle and kidney samples by pressurized liquid extraction or ultrasound-assisted extraction followed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry (HPLC-QqLIT-MS/MS).

PubMed

Hoff, Rodrigo Barcellos; Pizzolato, Tânia Mara; Peralba, Maria do Carmo Ruaro; Díaz-Cruz, M Silvia; Barceló, Damià

2015-03-01

Sulfonamides are widely used in human and veterinary medicine. The presence of sulfonamides residues in food is an issue of great concern. Throughout the present work, a method for the targeted analysis of 16 sulfonamides and metabolites residue in liver of several species has been developed and validated. Extraction and clean-up has been statistically optimized using central composite design experiments. Two extraction methods have been developed, validated and compared: i) pressurized liquid extraction, in which samples were defatted with hexane and subsequently extracted with acetonitrile and ii) ultrasound-assisted extraction with acetonitrile and further liquid-liquid extraction with hexane. Extracts have been analyzed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry. Validation procedure has been based on the Commission Decision 2002/657/EC and included the assessment of parameters such as decision limit (CCα), detection capability (CCβ), sensitivity, selectivity, accuracy and precision. Method׳s performance has been satisfactory, with CCα values within the range of 111.2-161.4 µg kg(-1), limits of detection of 10 µg kg(-1) and accuracy values around 100% for all compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

Method development for quantification of quizartinib in rat plasma by liquid chromatography/tandem mass spectrometry for pharmacokinetic application.

PubMed

Ezzeldin, Essam; Iqbal, Muzaffar; Mostafa, Gamal; Al-Rashood, Khalid A; El-Nahhas, Toqa

2018-03-01

Quizartinib is a highly potent inhibitor of the fms-like tyrosine kinase receptor, which is one of the most commonly mutated genes in acute myeloid leukemia. Quizartinib has shown a significant antileukemic clinical influence among relapsed/refractory acute myeloid leukemia patients. This study aimed at developing and validating an analytical method for the measurement of quizartinib in rat plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated according to US Food and Drug Administration guidelines, and the results obtained in this work met the set criteria. Liquid-liquid extraction was used and chromatographic separation was achieved on a BEHTM C 18 column. Detection of quizartinib was achieved in multiple reaction monitoring mode using positive-ion mode electrospray ionization. The MS/MS ion transitions at mass-to-charge ratios (m/z) of 561.129/114.09 and 441.16/84.03 were monitored for quizartinib and ibrutinib, respectively. The linear detection range was 2-1000 ng/mL (r > 0.998), with intra- and inter-day assay precisions ≤13.07 and 13.17%, respectively. This rapid, simple and sensitive method was validated and successfully applied to the pharmacokinetic study of quizartinib in rat samples. Copyright © 2017 John Wiley & Sons, Ltd.

Simultaneous determination of naringenin and hesperetin in rats after oral administration of Da-Cheng-Qi decoction by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Liu, Ying; Xu, Fengguo; Zhang, Zunjian; Song, Rui; Tian, Yuan

2008-07-01

To quantify naringenin and hesperetin in rat plasma after oral administration of Da-Cheng-Qi decoction, a famous purgative traditional Chinese medicine, a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated. The HPLC separation was carried out on a Zorbax SB-C(18) column using 0.1% formic acid-methanol as mobile phase and estazolam as internal standard after the sample of rat plasma had been cleaned up with one-step protein precipitation using methanol. Atmospheric pressure chemical ionization in the positive ion mode and selected reaction monitoring method was developed to determine the active components. This method was validated in terms of recovery, linearity, accuracy and precision (intra- and inter-batch variation). The recoveries of naringenin and hesperetin were 72.8-76.6 and 75.7-77.2%, respectively. Linearity in rat plasma was observed over the range of 0.5-250 ng/mL (r2 > 0.99) for both naringenin and hesperetin. The accuracy and precision were well within the acceptable range and the relative standard deviation of the measured rat plasma samples was less than 15% (n = 5). The validated method was successfully applied for the evaluation of the pharmacokinetics of naringenin and hesperetin administered to six rats.

A high-performance liquid chromatography-tandem mass spectrometry method coupled with protein precipitation for determination of granisetron in human plasma and its application to a comparative pharmacokinetic study.

PubMed

Zhou, Ying; Jiang, Ji; Hu, Pei; Wang, Hongyun

2014-12-01

A rapid, simple and validated method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has been developed for the determination of granisetron in human plasma. Plasma samples were pre-purified by protein precipitation procedure. The chromatographic separation was achieved with Synergi Polar-RP (75 × 2 mm, 4 µm) column using a mixture of 5 mm pH4.0 ammonium formate and methanol (300:316, v/v) under isocratic conditions at a flow rate of 0.3 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The analysis time was about 2.5 min. The method was fully validated over the concentration range 0.1-10 ng/mL. The lower limit of quantification was 0.1 ng/mL. Inter- and intra-batch precision was <6.1% and the accuracy was within 95.6-100.0%. The mean extraction recovery was 96.3%. Selectivity, matrix effect and stability were also validated. The method was applied to the comparative pharmacokinetic study of granisetron in Chinese healthy subjects. Copyright © 2014 John Wiley & Sons, Ltd.

Simultaneous determination of residues in pollen and high-fructose corn syrup from eight neonicotinoid insecticides by liquid chromatography-tandem mass spectrometry.

PubMed

Chen, Mei; Collins, Erin M; Tao, Lin; Lu, Chensheng

2013-11-01

The neonicotinoids have recently been identified as a potential contributing factor to the sudden decline in adult honeybee population, commonly known as colony collapse disorder (CCD). To protect the health of honeybees and other pollinators, a new, simple, and sensitive liquid chromatography-electrospray ionization mass spectrometry method was developed and validated for simultaneous determination of eight neonicotinoids, including acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam, in pollen and high-fructose corn syrup (HFCS). In this method, eight neonicotinoids, along with their isotope-labeled internal standards, were extracted from 2 g of pollen or 5 g of HFCS using an optimized quick, easy, cheap, effective, rugged, and safe extraction procedure. The method limits of detection in pollen and HFCS matrices were 0.03 ng/g for acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam and ranged between 0.03 and 0.1 ng/g for nitenpyram and flonicamid. The precision and accuracy were well within the acceptable 20% range. Selectivity, linearity, lower limit of quantitation, matrix effect, recovery, and stability in autosampler were also evaluated during validation. This validated method has been used successfully in analyzing a set of pollen and HFCS samples collected for evaluating potential honeybee exposure to neonicotinoids.

High-throughput method for macrolides and lincosamides antibiotics residues analysis in milk and muscle using a simple liquid-liquid extraction technique and liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-MS/MS).

PubMed

Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Campos Motta, Tanara Magalhães; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

2015-11-01

A fast and simple method for residue analysis of the antibiotics classes of macrolides (erythromycin, azithromycin, tylosin, tilmicosin and spiramycin) and lincosamides (lincomycin and clindamycin) was developed and validated for cattle, swine and chicken muscle and for bovine milk. Sample preparation consists in a liquid-liquid extraction (LLE) with acetonitrile, followed by liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-ESI-MS/MS), without the need of any additional clean-up steps. Chromatographic separation was achieved using a C18 column and a mobile phase composed by acidified acetonitrile and water. The method was fully validated according the criteria of the Commission Decision 2002/657/EC. Validation parameters such as limit of detection, limit of quantification, linearity, accuracy, repeatability, specificity, reproducibility, decision limit (CCα) and detection capability (CCβ) were evaluated. All calculated values met the established criteria. Reproducibility values, expressed as coefficient of variation, were all lower than 19.1%. Recoveries range from 60% to 107%. Limits of detection were from 5 to 25 µg kg(-1).The present method is able to be applied in routine analysis, with adequate time of analysis, low cost and a simple sample preparation protocol. Copyright © 2015. Published by Elsevier B.V.

HPLC-ESI-MS/MS validated method for simultaneous quantification of zopiclone and its metabolites, N-desmethyl zopiclone and zopiclone-N-oxide in human plasma.

PubMed

Mistri, Hiren N; Jangid, Arvind G; Pudage, Ashutosh; Shrivastav, Pranav

2008-03-15

A simple, selective and sensitive isocratic HPLC method with triple quadrupole mass spectrometry detection has been developed and validated for simultaneous quantification of zopiclone and its metabolites in human plasma. The analytes were extracted using solid phase extraction, separated on Symmetry shield RP8 column (150 mm x 4.6 mm i.d., 3.5 microm particle size) and detected by tandem mass spectrometry with a turbo ion spray interface. Metaxalone was used as an internal standard. The method had a chromatographic run time of 4.5 min and linear calibration curves over the concentration range of 0.5-150 ng/mL for both zopiclone and N-desmethyl zopiclone and 1-150 ng/mL for zopiclone-N-oxide. The intra-batch and inter-batch accuracy and precision evaluated at lower limit of quantification and quality control levels were within 89.5-109.1% and 3.0-14.7%, respectively, for all the analytes. The recoveries calculated for the analytes and internal standard were > or = 90% from spiked plasma samples. The validated method was successfully employed for a comparative bioavailability study after oral administration of 7.5 mg zopiclone (test and reference) to 16 healthy volunteers under fasted condition.

Investigation of the presence of β-hydroxy-β-methylbutyric acid and α-hydroxyisocaproic acid in bovine whole milk and fermented dairy products by a validated liquid chromatography-mass spectrometry method.

PubMed

Ehling, Stefan; Reddy, Todime M

2014-02-19

A simple, rugged, quantitative, and confirmatory method based on liquid chromatography-mass spectrometry was developed and comprehensively validated for the analysis of the leucine metabolites β-hydroxy-β-methylbutyric acid (HMB) and α-hydroxyisocaproic acid (HICA) in bovine whole milk and yogurt. Mean accuracy (90-110% for HMB and 85-115% for HICA) and total precision (<10% RSD in most cases, except for <20% RSD for HMB at the limit of quantitation) at four concentration levels across three validation runs have been determined. Limits of quantitation for HMB and HICA in whole milk were 20 and 5 μg/L, respectively. Measured concentrations of HMB and HICA were <20-29 and 32-37 μg/L, respectively, in bovine whole milk and <5 and 3.0-15.2 mg/L, respectively, in yogurt. These concentrations are insufficient by large margins to deliver any musculoskeletal benefits, and fortification of milk and dairy products with HMB and/or HICA appears to be justified.

Determination of rivaroxaban in patient's plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS).

PubMed

Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo Dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

2017-01-01

Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p < 0.001). In addition, we validated hemolytic, icteric or lipemic plasma samples for rivaroxaban measurement by HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels.

Development and validation of a method for gefitinib quantification in dried blood spots using liquid chromatography-tandem mass spectrometry: Application to finger-prick clinical blood samples of patients with non-small cell lung cancer.

PubMed

Irie, Kei; Shobu, Saori; Hiratsuji, Seika; Yamasaki, Yuta; Nanjo, Shigeki; Kokan, Chiyuki; Hata, Akito; Kaji, Reiko; Masago, Katsuhiro; Fujita, Shiro; Okada, Yutaka; Katakami, Nobuyuki; Fukushima, Shoji

2018-06-15

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of gefitinib in dried blood spots (DBSs). Gefitinib was extracted with methanol from DBS of 3 mm in diameter and detected using a triple quadrupole mass spectrometer. The method was validated by evaluating its precision, accuracy, selectivity, carryover, matrix effect, recovery, and stability. For clinical validation, paired finger-prick DBS and plasma concentrations were compared for 10 patients with non-small cell lung cancer (NSCLC) taking gefitinib. The calibration linear range was 37.5-2400 ng/mL (coefficient of determination [R 2 ] = 0.99), encompassing the therapeutic concentrations of gefitinib. The accuracy and precision were within 15% of the quality control (QC) concentrations of 80, 200, and 2000 ng/mL. The lower limit of quantification was determined to be 40 ng/mL. Gefitinib was stable in DBSs for up to 5 months at room temperature and -20 °C, and at 40 °C for 24 h. A good correlation was observed between the gefitinib levels measured by the DBS method and plasma concentrations (R 2  = 0.99). This method provides a simple, fast, and accurate approach to the quantitative analysis of gefitinib in finger-prick DBSs. The method would be useful for minimally invasive evaluation of the clinical gefitinib blood concentration. Copyright © 2018 Elsevier B.V. All rights reserved.

Validation of a new screening, determinative, and confirmatory multi-residue method for nitroimidazoles and their hydroxy metabolites in turkey muscle tissue by liquid chromatography-tandem mass spectrometry.

PubMed

Boison, Joe O; Asea, Philip A; Matus, Johanna L

2012-08-01

A new and sensitive multi-residue method (MRM) with detection by LC-MS/MS was developed and validated for the screening, determination, and confirmation of residues of 7 nitroimidazoles and 3 of their metabolites in turkey muscle tissues at concentrations ≥ 0.05 ng/g. The compounds were extracted into a solvent with an alkali salt. Sample clean-up and concentration was then done by solid-phase extraction (SPE) and the compounds were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The characteristic parameters including repeatability, selectivity, ruggedness, stability, level of quantification, and level of confirmation for the new method were determined. Method validation was achieved by independent verification of the parameters measured during method characterization. The seven nitroimidazoles included are metronidazole (MTZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole (TNZ), ornidazole (ONZ), ipronidazole (IPR), and carnidazole (CNZ). It was discovered during the single laboratory validation of the method that five of the seven nitroimidazoles (i.e. metronidazole, dimetridazole, tinidazole, ornidazole and ipronidazole) and the 3 metabolites (1-(2-hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole (MTZ-OH), 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the common metabolite of ronidazole and dimetridazole), and 1-methyl-2-(2'-hydroxyisopropyl)-5-nitroimidazole (IPR-OH) included in this study could be detected, confirmed, and quantified accurately whereas RNZ and CNZ could only be detected and confirmed but not accurately quantified. © Her Majesty the Queen in Right of Canada as Represented by the Minister of Agriculture and Agri-food Canada 2012.

Quantitative determination of galantamine in human plasma by sensitive liquid chromatography-tandem mass spectrometry using loratadine as an internal standard.

PubMed

Nirogi, Ramakrishna V S; Kandikere, Vishwottam N; Mudigonda, Koteshwara; Maurya, Santosh

2007-02-01

A simple, rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry method is developed and validated for the quantitation of galantamine, an acetylcholinesterase inhibitor in human plasma, using a commercially available compound, loratadine, as the internal standard. Following liquid-liquid extraction, the analytes are separated using an isocratic mobile phase on a reverse-phase C18 column and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective (M+H)+ ions, m/z 288 to 213 for galantamine and m/z 383 and 337 for the internal standard. The assay exhibit a linear dynamic range of 0.5-100 ng/mL for galantamine in human plasma. The lower limit of quantitation is 0.5 ng/mL, with a relative standard deviation of less than 8%. Acceptable precision and accuracy are obtained for concentrations over the standard curve range. A run time of 2.5 min for each sample makes it possible to analyze more than 400 human plasma samples per day. The validated method is successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability, or bioequivalence studies.

Development and validation of a hydrophilic interaction chromatography-mass spectrometry assay for taurine and methionine in matrices rich in carbohydrates.

PubMed

de Person, Marine; Hazotte, Aurélie; Elfakir, Claire; Lafosse, Michel

2005-07-22

A new procedure based on hydrophilic interaction chromatography coupled to tandem mass spectrometry (ionisation process by pneumatically assisted electrospray in negative ion mode), is developed and validated for the simultaneous determination of underivatised taurine and methionine in beverages rich in carbohydrates such as energy drinks. No initial clean-up procedure and no sample derivatisation are required. Satisfactory analysis was obtained on an Astec apHera NH2 (150 mm x 4.6 mm; 5 microm) column with methanol-water (60/40) as mobile phase. The method was validated in terms of specificity, detection limits, linearity, accuracy, precision and stability, using threonine as internal standard. The potential effects of matrix and endogenous amino acid content were also examined. The limits of detection in the beverage varied from 20 microg L(-1) for taurine to 50 micro L(-1) for methionine.

Determination of Grayanotoxins from Rhododendron brachycarpum in Dietary Supplements and Homemade Wine by Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Hwang, Taeik; Noh, Eunyoung; Jeong, Ji Hye; Park, Sung-Kwan; Shin, Dongwoo; Kang, Hoil

2018-02-28

A sensitive and specific high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of grayanotoxins I and III in dietary supplements and homemade wine. Grayanotoxins I and III were successfully extracted using solid-phase extraction cartridges, characterized by LC-QTOF-MS, and quantitated by LC-MS/MS. The LC-MS/MS calibration curves were linear over concentrations of 10-100 ng/mL (grayanotoxin I) and 20-400 ng/mL (grayanotoxin III). Grayanotoxins I and III were found in 51 foodstuffs, with quantitative determinations revealing total toxin concentrations of 18.4-101 000 ng/mL (grayanotoxin I) and 15.3-56 000 ng/mL (grayanotoxin III). The potential of the validated method was demonstrated by successful quantitative analysis of grayanotoxins I and III in dietary supplements and homemade wine; the method appears suitable for the routine detection of grayanotoxins I and III from Rhododendron brachycarpum.

Development and validation of LC-HRMS and GC-NICI-MS methods for stereoselective determination of MDMA and its phase I and II metabolites in human urine

PubMed Central

Schwaninger, Andrea E.; Meyer, Markus R.; Huestis, Marilyn A.; Maurer, Hans H.

2013-01-01

3,4-Methylenedioxymethamphetamine (MDMA) is a racemic drug of abuse and its R- and S-enantiomers are known to differ in their dose-response curve. The S-enantiomer was shown to be eliminated at a higher rate than the R-enantiomer most likely explained by stereoselective metabolism that was observed in various in vitro experiments. The aim of this work was the development and validation of methods for evaluating the stereoselective elimination of phase I and particularly phase II metabolites of MDMA in human urine. Urine samples were divided into three different methods. Method A allowed stereoselective determination of the 4-hydroxy-3-methoxymethamphetamine (HMMA) glucuronides and only achiral determination of the intact sulfate conjugates of HMMA and 3,4-dihydroxymethamphetamine (DHMA) after C18 solid-phase extraction by liquid chromatography–high-resolution mass spectrometry with electrospray ionization. Method B allowed the determination of the enantiomer ratios of DHMA and HMMA sulfate conjugates after selective enzymatic cleavage and chiral analysis of the corresponding deconjugated metabolites after chiral derivatization with S-heptafluorobutyrylprolyl chloride using gas chromatography–mass spectrometry with negativeion chemical ionization. Method C allowed the chiral determination of MDMA and its unconjugated metabolites using method B without sulfate cleavage. The validation process including specificity, recovery, matrix effects, process efficiency, accuracy and precision, stabilities and limits of quantification and detection showed that all methods were selective, sensitive, accurate and precise for all tested analytes. PMID:21656610

Analysis of iodinated X-ray contrast agents in water samples by ion chromatography and inductively-coupled plasma mass spectrometry.

PubMed

Sacher, Frank; Raue, Brigitte; Brauch, Heinz-Jürgen

2005-08-26

In this paper, an analytical method for the determination of six iodinated X-ray contrast agents (amidotrizoic acid, iohexol, iomeprol, iopamidol, iopromide, and ioxitalamic acid), iodide, and iodate in water samples is presented. The method is based on a separation of the analytes by ion chromatography (IC) and a subsequent detection by inductively-coupled plasma mass spectrometry (ICP-MS). The method was optimised with respect to separation conditions (column type and eluent composition) and extensively validated. Without pre-concentration of the samples, limits of detection below 0.2 microg/l could be achieved whereby reproducibility was below 6% for all compounds under investigation.

Development of analytical methods for multiplex bio-assay with inductively coupled plasma mass spectrometry.

PubMed

Ornatsky, Olga I; Kinach, Robert; Bandura, Dmitry R; Lou, Xudong; Tanner, Scott D; Baranov, Vladimir I; Nitz, Mark; Winnik, Mitchell A

2008-01-01

Advances in the development of highly multiplexed bio-analytical assays with inductively coupled plasma mass spectrometry (ICP-MS) detection are discussed. Use of novel reagents specifically designed for immunological methods utilizing elemental analysis is presented. The major steps of method development, including selection of elements for tags, validation of tagged reagents, and examples of multiplexed assays, are considered in detail. The paper further describes experimental protocols for elemental tagging of antibodies, immunostaining of live and fixed human leukemia cells, and preparation of samples for ICP-MS analysis. Quantitative analysis of surface antigens on model cell lines using a cocktail of seven lanthanide labeled antibodies demonstrated high specificity and concordance with conventional immunophenotyping.

Data Validation Standard Operating Procedure for EPA Method 1613 Revision B, Tetra-through Octa-chlorinated Dioxins and Furans by Isotope Dillution (High Resolution Gas Chromatography/High Resolution Mass Spectrometry)

EPA Pesticide Factsheets

Method used for isomer specific determination todetect the Tetra- through octa- chlorinated dibenzo-p-dioxins and dibenzofurans associatedwith the CWA, RCRA, Comprehensive Environmental Response, Compensation and Liability Act and the SDWA

Accurate Quantitation and Analysis of Nitrofuran Metabolites, Chloramphenicol, and Florfenicol in Seafood by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry: Method Validation and Regulatory Samples.

PubMed

Aldeek, Fadi; Hsieh, Kevin C; Ugochukwu, Obiadada N; Gerard, Ghislain; Hammack, Walter

2018-05-23

We developed and validated a method for the extraction, identification, and quantitation of four nitrofuran metabolites, 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), semicarbazide (SC), and 1-aminohydantoin (AHD), as well as chloramphenicol and florfenicol in a variety of seafood commodities. Samples were extracted by liquid-liquid extraction techniques, analyzed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and quantitated using commercially sourced, derivatized nitrofuran metabolites, with their isotopically labeled internal standards in-solvent. We obtained recoveries of 90-100% at various fortification levels. The limit of detection (LOD) was set at 0.25 ng/g for AMOZ and AOZ, 1 ng/g for AHD and SC, and 0.1 ng/g for the phenicols. Various extraction methods, standard stability, derivatization efficiency, and improvements to conventional quantitation techniques were also investigated. We successfully applied this method to the identification and quantitation of nitrofuran metabolites and phenicols in 102 imported seafood products. Our results revealed that four of the samples contained residues from banned veterinary drugs.

Accurate mass measurement by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. I. Measurement of positive radical ions using porphyrin standard reference materials.

PubMed

Griffiths, Nia W; Wyatt, Mark F; Kean, Suzanna D; Graham, Andrew E; Stein, Bridget K; Brenton, A Gareth

2010-06-15

A method for the accurate mass measurement of positive radical ions by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) is described. Initial use of a conjugated oligomeric calibration material was rejected in favour of a series of meso-tetraalkyl/tetraalkylaryl-functionalised porphyrins, from which the two calibrants required for a particular accurate mass measurement were chosen. While all measurements of monoisotopic species were within +/-5 ppm, and the method was rigorously validated using chemometrics, mean values of five measurements were used for extra confidence in the generation of potential elemental formulae. Potential difficulties encountered when measuring compounds containing multi-isotopic elements are discussed, where the monoisotopic peak is no longer the lowest mass peak, and a simple mass-correction solution can be applied. The method requires no significant expertise to implement, but care and attention is required to obtain valid measurements. The method is operationally simple and will prove useful to the analytical chemistry community. Copyright (c) 2010 John Wiley & Sons, Ltd.

Evaluation of the QuEChERS Method and Gas Chromatography–Mass Spectrometry for the Analysis Pesticide Residues in Water and Sediment

PubMed Central

de Macedo, A. N.; Vicente, G. H. L.; Nogueira, A. R. A.

2010-01-01

A method for the determination of pesticide residues in water and sediment was developed using the QuEChERS method followed by gas chromatography – mass spectrometry. The method was validated in terms of accuracy, specificity, linearity, detection and quantification limits. The recovery percentages obtained for the pesticides in water at different concentrations ranged from 63 to 116%, with relative standard deviations below 12%. The corresponding results from the sediment ranged from 48 to 115% with relative standard deviations below 16%. The limits of detection for the pesticides in water and sediment were below 0.003 mg L−1 and 0.02 mg kg−1, respectively. PMID:21165598

Mass spectrometry detection of fraudulent use of cow whey in water buffalo, sheep, or goat Italian ricotta cheese.

PubMed

Camerini, Serena; Montepeloso, Emanuela; Casella, Marialuisa; Crescenzi, Marco; Marianella, Rosa Maria; Fuselli, Fabio

2016-04-15

Ricotta cheese is a typical Italian product, made with whey from various species, including cow, buffalo, sheep, and goat. Ricotta cheese nominally manufactured from the last three species may be fraudulently produced using the comparatively cheaper cow whey. Exposing such food frauds requires a reliable analytical method. Despite the extensive similarities shared by whey proteins of the four species, a mass spectrometry-based analytical method was developed that exploits three species-specific peptides derived from β-lactoglobulin and α-lactalbumin. This method can detect as little as 0.5% bovine whey in ricotta cheese from the other three species. Furthermore, a tight correlation was found (R(2)>0.99) between cow whey percentages and mass spectrometry measurements throughout the 1-50% range. Thus, this method can be used for forensic detection of ricotta cheese adulteration and, if properly validated, to provide quantitative evaluations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of three steroidal saponins from Ophiopogon japonicus (Liliaceae) via high-performance liquid chromatography with mass spectrometry.

PubMed

Wang, Yongyi; Xu, Jinzhong; Qu, Haibin

2013-01-01

A simple and accurate analytical method was developed for simultaneous quantification of three steroidal saponins in the roots of Ophiopogon japonicus via high-performance liquid chromatography (HPLC) with mass spectrometry (MS) in this study. Separation was performed on a Tigerkin C(18) column and detection was performed by mass spectrometry. A mobile phase consisted of 0.02% formic acid in water (v/v) and 0.02% formic acid in acetonitrile (v/v) was used with a flow rate of 0.5 mL min(-1). The quantitative HPLC-MS method was validated for linearity, precision, repeatability, stability, recovery, limits of detection and quantification. This developed method provides good linearity (r >0.9993), intra- and inter-day precisions (RSD <4.18%), repeatability (RSD <5.05%), stability (RSD <2.08%) and recovery (93.82-102.84%) for three steroidal saponins. It could be considered as a suitable quality control method for O. japonicus.

Development and Validation of an Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Method for Quantitative Analysis of Platinum in Plasma, Urine, and Tissues.

PubMed

Zhang, Ti; Cai, Shuang; Forrest, Wai Chee; Mohr, Eva; Yang, Qiuhong; Forrest, M Laird

2016-09-01

Cisplatin, a platinum chemotherapeutic, is one of the most commonly used chemotherapeutic agents for many solid tumors. In this work, we developed and validated an inductively coupled plasma mass spectrometry (ICP-MS) method for quantitative determination of platinum levels in rat urine, plasma, and tissue matrices including liver, brain, lungs, kidney, muscle, heart, spleen, bladder, and lymph nodes. The tissues were processed using a microwave accelerated reaction system (MARS) system prior to analysis on an Agilent 7500 ICP-MS. According to the Food and Drug Administration guidance for industry, bioanalytical validation parameters of the method, such as selectivity, accuracy, precision, recovery, and stability were evaluated in rat biological samples. Our data suggested that the method was selective for platinum without interferences caused by other presenting elements, and the lower limit of quantification was 0.5 ppb. The accuracy and precision of the method were within 15% variation and the recoveries of platinum for all tissue matrices examined were determined to be 85-115% of the theoretical values. The stability of the platinum-containing solutions, including calibration standards, stock solutions, and processed samples in rat biological matrices was investigated. Results indicated that the samples were stable after three cycles of freeze-thaw and for up to three months. © The Author(s) 2016.

Development and Validation of an Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Method for Quantitative Analysis of Platinum in Plasma, Urine, and Tissues

PubMed Central

Zhang, Ti; Cai, Shuang; Forrest, Wai Chee; Mohr, Eva; Yang, Qiuhong; Forrest, M. Laird

2016-01-01

Cisplatin, a platinum chemotherapeutic, is one of the most commonly used chemotherapeutic agents for many solid tumors. In this work, we developed and validated an inductively coupled plasma mass spectrometry (ICP-MS) method for quantitative determination of platinum levels in rat urine, plasma, and tissue matrices including liver, brain, lungs, kidney, muscle, heart, spleen, bladder, and lymph nodes. The tissues were processed using a microwave accelerated reaction system (MARS) system prior to analysis on an Agilent 7500 ICP-MS. According to the Food and Drug Administration guidance for industry, bioanalytical validation parameters of the method, such as selectivity, accuracy, precision, recovery, and stability were evaluated in rat biological samples. Our data suggested that the method was selective for platinum without interferences caused by other presenting elements, and the lower limit of quantification was 0.5 ppb. The accuracy and precision of the method were within 15% variation and the recoveries of platinum for all tissue matrices examined were determined to be 85–115% of the theoretical values. The stability of the platinum-containing solutions, including calibration standards, stock solutions, and processed samples in rat biological matrices was investigated. Results indicated that the samples were stable after three cycles of freeze–thaw and for up to three months. PMID:27527103

Development and validation of LC-MS/MS methods for the determination of mirabegron and its metabolites in human plasma and their application to a clinical pharmacokinetic study.

PubMed

Teijlingen, Raymond van; Meijer, John; Takusagawa, Shin; Gelderen, Marcel van; Beld, Cas van den; Usui, Takashi

2012-03-01

Mirabegron is being developed for the treatment of overactive bladder. To support the development of mirabegron, including pharmacokinetic studies, liquid chromatography/tandem mass spectrometry methods for mirabegron and eight metabolites (M5, M8, M11-M16) were developed and validated for heparinized human plasma containing sodium fluoride. Four separate bioanalytical methods were developed for the analysis of: (1) mirabegron; (2) M5 and M16; (3) M8; and (4) M11-M15. Either solid-phase extraction or liquid-liquid extraction was used to extract the analytes of interest from matrix constituents. For mirabegron, an Inertsil C₈-3 analytical column was used and detection was performed using a triple-quad mass spectrometer equipped with an atmospheric pressure chemical ionization interface. For the metabolite assays, chromatographic separation was performed through a Phenomenex Synergi Fusion-RP C₁₈ analytical column and detection was performed using a triple-quad mass spectrometer equipped with a Heated Electrospray Ionization interface. The validation results demonstrated that the developed liquid chromatography/tandem mass spectrometry methods were precise, accurate, and selective for the determination of mirabegron and its metabolites in human plasma. All methods were successfully applied in evaluating the pharmacokinetic parameters of mirabegron and metabolites in human plasma. Copyright © 2012 Elsevier B.V. All rights reserved.

High-resolution gas chromatography/mas spectrometry method for characterization and quantitative analysis of ginkgolic acids in ginkgo biloba plants, extracts, and dietary supplements

USDA-ARS?s Scientific Manuscript database

A high resolution GC/MS with Selected Ion Monitor (SIM) method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts and commercial products was developed and validated. The method involved sample extraction with (1:1) meth...

Development and Validation of a Sensitive Method for Trace Nickel Determination by Slotted Quartz Tube Flame Atomic Absorption Spectrometry After Dispersive Liquid-Liquid Microextraction.

PubMed

Yolcu, Şükran Melda; Fırat, Merve; Chormey, Dotse Selali; Büyükpınar, Çağdaş; Turak, Fatma; Bakırdere, Sezgin

2018-05-01

In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1 µg L -1 . Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method.

A method for the complete analysis of NORM building materials by γ-ray spectrometry using HPGe detectors.

PubMed

Quintana, B; Pedrosa, M C; Vázquez-Canelas, L; Santamaría, R; Sanjuán, M A; Puertas, F

2018-04-01

A methodology including software tools for analysing NORM building materials and residues by low-level gamma-ray spectrometry has been developed. It comprises deconvolution of gamma-ray spectra using the software GALEA with focus on the natural radionuclides and Monte Carlo simulations for efficiency and true coincidence summing corrections. The methodology has been tested on a range of building materials and validated against reference materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of total and unbound concentrations of lopinavir in plasma using liquid chromatography-tandem mass spectrometry and ultrafiltration methods.

PubMed

Illamola, S M; Labat, L; Benaboud, S; Tubiana, R; Warszawski, J; Tréluyer, J M; Hirt, D

2014-08-15

Lopinavir is an HIV protease inhibitor with high protein binding (98-99%) in human plasma. This study was designed to develop an ultrafiltration method to measure the unbound concentrations of lopinavir overcoming the non-specific binding issue. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of total concentrations of lopinavir in plasma was developed and validated, and an adaptation was also optimized and validated for the determination of unbound concentrations. The chromatographic separation was performed with a C18 column (100 mm × 2.1mm i.d., 5 μm particle size) using a mobile phase containing deionized water with formic acid, and acetonitrile, with gradient elution at a flow-rate of 350 μL min(-1). Identification of the compounds was performed by multiple reaction monitoring, using electrospray ionization in positive ion mode. The method was validated over a clinical range of 0.01-1 μg/mL for human plasma ultrafiltrate and 0.1-15 μg/mL in human plasma. The inter and intra-assay accuracies and precisions were between 0.23% and 11.37% for total lopinavir concentrations, and between 3.50% and 13.30% for plasma ultrafiltrate (unbound concentration). The ultrafiltration method described allows an accurate separation of the unbound fraction of lopinavir, circumscribing the loss of drug by nonspecific binding (NSB), and the validated LC-MS/MS methodology proposed is suitable for the determination of total and unbound concentrations of lopinavir in clinical practice. Copyright © 2014 Elsevier B.V. All rights reserved.

Mesoporous Silica Nanoparticles as an Adsorbent for Preconcentration and Determination of Trace Amount of Nickel in Environmental Samples by Atom Trap Flame Atomic Absorption Spectrometry

NASA Astrophysics Data System (ADS)

Shirkhanloo, H.; Falahnejad, M.; Zavvar Mousavi, H.

2016-01-01

A rapid enrichment method based on solid-phase extraction (SPE) has been established for preconcentration and separation of trace Ni(II) ions in water samples prior to their determination by atom trap flame atomic absorption spectrometry. A column filled with bulky NH2-UVM7 was used as the novel adsorbent. Under optimal conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were 3-92 μg/L, 0.8 μg/L, and 100, respectively. The validity of the method was checked by the standard reference material.

Development of a liquid chromatography–tandem mass spectrometry method for the determination of sulfonamides, trimethoprim and dapsone in honey and validation according to Commission Decision 2002/657/EC for banned compounds [corrected].

PubMed

Economou, Anastasios; Petraki, Olympia; Tsipi, Despina; Botitsi, Eleni

2012-08-15

This work reports a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for identification and quantification of seven sulfonamides, trimethoprim and dapsone in honey. The method is based on a solid-phase extraction (SPE) step of the target analytes with Oasis HLB cartridges after acidic hydrolysis of the honey sample to liberate the sugar-bound sulfonamides. Analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive electro-spray ionization (ESI) mode with two different isotopically labeled internal standards with the view to improve the quantitative performance of the method. The method validation has been performed according to the Commission Decision 2002/657/EC; the average recoveries, measured at three concentration levels (1.5, 2.5 and 5.0 μg kg(-1)), have been estimated in the range 70 to 106% while the respective % relative standard deviations of the within-laboratory reproducibility ranged from 6 to 18%. Mean values of the expanded uncertainties calculated were in the range 22-41% at the 99% confidence level. Decision limit (CCα) and detection capability (CCβ) values were in the ranges 0.4-0.9 and 0.7-1.4 μg kg(-1), respectively. Matrix effects have been investigated demonstrating a moderate signal suppression/enhancement for most of the target compounds. The method described has been successfully applied to the analysis of honey samples; sulfamethoxazole, sulfathiazole and trimethoprim were detected in some cases. Copyright © 2012 Elsevier B.V. All rights reserved.

A rapid and sensitive LC-MS/MS method for the determination of Pulsatilla saponin D in rat plasma and its application in a rat pharmacokinetic and bioavailability study.

PubMed

Ouyang, Hui; Guo, Yicheng; He, Mingzhen; Zhang, Jinlian; Huang, Xiaofang; Zhou, Xin; Jiang, Hongliang; Feng, Yulin; Yang, Shilin

2015-03-01

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of Pulsatilla saponin D, a potential antitumor constituent isolated from Pulsatilla chinensis in rat plasma. Rat plasma samples were pretreated by protein precipitation with methanol. The method validation was performed in accordance with US Food and Drug Administration guidelines and the results met the acceptance criteria. The method was successfully applied to assess the pharmacokinetics and oral bioavailability of Pulsatilla saponin D in rats. Copyright © 2014 John Wiley & Sons, Ltd.

Quantitative determination of total cesium in highly active liquid waste by using liquid electrode plasma optical emission spectrometry.

PubMed

Do, Van-Khoai; Yamamoto, Masahiko; Taguchi, Shigeo; Takamura, Yuzuru; Surugaya, Naoki; Kuno, Takehiko

2018-06-01

A sensitive analytical method for determination of total cesium (Cs) in highly active liquid waste (HALW) by using modified liquid electrode plasma optical emission spectrometry (LEP-OES) is developed in this study. The instrument is modified to measure radioactive samples in a glove box. The effects of important factors, including pulsed voltage sequence and nitric acid concentration, on the emission of Cs are investigated. The limit of detection (LOD) and limit of quantification (LOQ) are 0.005 mg/L and 0.02 mg/L, respectively. The achieved LOD is one order lower than that of recently developed spectroscopic methods using liquid discharge plasma. The developed method is validated by subjecting a simulated HALW sample to inductively coupled plasma mass spectrometry (ICP-MS). The recoveries obtained from a spike-and-recovery test are 96-102%, implying good accuracy. The method is successfully applied to the quantification of Cs in a real HALW sample at the Tokai reprocessing plant in Japan. Apart from dilution and filtration of the HALW sample, no other pre-treatment process is required. The results agree well with the values obtained using gamma spectrometry. The developed method offers a reliable technique for rapid analysis of total Cs in HALW samples. Copyright © 2018 Elsevier B.V. All rights reserved.

[Validation Study for Analytical Method of Diarrhetic Shellfish Poisons in 9 Kinds of Shellfish].

PubMed

Yamaguchi, Mizuka; Yamaguchi, Takahiro; Kakimoto, Kensaku; Nagayoshi, Haruna; Okihashi, Masahiro; Kajimura, Keiji

2016-01-01

A method was developed for the simultaneous determination of okadaic acid, dinophysistoxin-1 and dinophysistoxin-2 in shellfish using ultra performance liquid chromatography with tandem mass spectrometry. Shellfish poisons in spiked samples were extracted with methanol and 90% methanol, and were hydrolyzed with 2.5 mol/L sodium hydroxide solution. Purification was done on an HLB solid-phase extraction column. This method was validated in accordance with the notification of Ministry of Health, Labour and Welfare of Japan. As a result of the validation study in nine kinds of shellfish, the trueness, repeatability and within-laboratory reproducibility were 79-101%, less than 12 and 16%, respectively. The trueness and precision met the target values of notification.

A simple validated multi-analyte method for detecting drugs in oral fluid by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

PubMed

Zheng, Yufang; Sparve, Erik; Bergström, Mats

2018-06-01

A UPLC-MS/MS method was developed to identify and quantitate 37 commonly abused drugs in oral fluid. Drugs of interest included amphetamines, benzodiazepines, cocaine, opiates, opioids, phencyclidine and tetrahydrocannabinol. Sample preparation and extraction are simple, and analysis times short. Validation showed satisfactory performance at relevant concentrations. The possibility of contaminated samples as well as the interpretation in relation to well-knows matrices, such as urine, will demand further study. Copyright © 2017 John Wiley & Sons, Ltd.

Development and validation of an ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method for the simultaneous determination of selected flavonoids in Ginkgo biloba.

PubMed

Pandey, Renu; Chandra, Preeti; Arya, Kamal Ram; Kumar, Brijesh

2014-12-01

A rapid and sensitive ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of 13 flavonoids in leaf, stem, and fruit extracts of male and female trees of Ginkgo biloba to investigate gender- and age-related variations of flavonoids content. Chromatographic separation was accomplished on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm id, 1.7 μm) in 5 min. Quantitation was performed using negative electrospray ionization mass spectrometry in multiple reaction monitoring mode. The calibration curves of all analytes showed a good linear relationship (r(2) ≥ 0.9977) over the concentration range of 1-1000 ng/mL. The precision evaluated by an intra- and interday study showed RSD ≤ 1.98% and good accuracy with overall recovery in the range from 97.90 to 101.09% (RSD ≤ 1.67%) for all analytes. The method sensitivity expressed as the limit of quantitation was typically 0.25-3.57 ng/mL. The results showed that the total content of 13 flavonoids was higher in the leaf extract of an old male Ginkgo tree compared to young female Ginkgo trees. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid chromatography-tandem mass spectrometry method for the analysis of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, a biocidal disinfectant, in dairy products.

PubMed

Slimani, Kahina; Pirotais, Yvette; Maris, Pierre; Abjean, Jean-Pierre; Hurtaud-Pessel, Dominique

2018-10-01

A novel and reliable method to quantify residual levels of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in dairy products using ion-pairing reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Sample extraction was done with salting-out technique using acetonitrile and sodium chloride. For LC-MS/MS, the analyte was detected using positive electrospray ionization (ESI+) and two multiple reaction monitoring (MRM) transitions were monitored. The method was validated in the 5-150 µg kg -1 range using total error approach. Thus, performance criteria of the method were evaluated. Relative standard deviations for trueness and precision were lower than 10%; with the exception of hard pressed cheese at 5 µg kg -1 for precision. The limit of quantification (LOQ) was around 5-7 µg kg -1 depending on the matrix of interest. The method was successfully applied to accurately quantify N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in 146 various dairy products with a maximum contamination level of 225 µg kg -1 in cheese. Copyright © 2018 Elsevier Ltd. All rights reserved.

A novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) based bioanalytical method for quantification of ethyl esters of Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) and its application in pharmacokinetic study.

PubMed

Viswanathan, Sekarbabu; Verma, P R P; Ganesan, Muniyandithevar; Manivannan, Jeganathan

2017-07-15

Omega-3 fatty acids are clinically useful and the two marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are prevalent in fish and fish oils. Omega-3 fatty acid formulations should undergo a rigorous regulatory step in order to obtain United States Food and Drug Administration (USFDA) approval as prescription drug. In connection with that, despite quantifying EPA and DHA fatty acids, there is a need for quantifying the level of ethyl esters of them in biological samples. In this study, we make use of reverse phase high performance liquid chromatography coupled with mass spectrometry (RP-HPLC-MS)technique for the method development. Here, we have developed a novel multiple reaction monitoring method along with optimized parameters for quantification of EPA and DHA as ethyl esters. Additionally, we attempted to validate the bio-analytical method by conducting the sensitivity, selectivity, precision accuracy batch, carryover test and matrix stability experiments. Furthermore, we also implemented our validated method for evaluation of pharmacokinetics of omega fatty acid ethyl ester formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

A Liquid Chromatography – Tandem Mass Spectrometry Approach for the Identification of Mebendazole Residue in Pork, Chicken, and Horse

PubMed Central

Lee, Ji Sun; Cho, Soo Hee; Lim, Chae Mi; Chang, Moon Ik; Joo, Hyun Jin; Park, Hyun Jin

2017-01-01

A confirmatory and quantitative method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of mebendazole and its hydrolyzed and reduced metabolites in pork, chicken, and horse muscles was developed and validated in this study. Anthelmintic compounds were extracted with ethyl acetate after sample mixture was made alkaline followed by liquid chromatographic separation using a reversed phase C18 column. Gradient elution was performed with a mobile phase consisting of water containing 10 mM ammonium formate and methanol. This confirmatory method was validated according to EU requirements. Evaluated validation parameters included specificity, accuracy, precision (repeatability and within-laboratory reproducibility), analytical limits (decision limit and detection limit), and applicability. Most parameters were proved to be conforming to the EU requirements. The decision limit (CCα) and detection capability (CCβ) for all analytes ranged from 15.84 to 17.96 μgkg-1. The limit of detection (LOD) and the limit of quantification (LOQ) for all analytes were 0.07 μgkg-1 and 0.2 μgkg-1, respectively. The developed method was successfully applied to monitoring samples collected from the markets in major cities and proven great potential to be used as a regulatory tool to determine mebendazole residues in animal based foods. PMID:28085912

Monitoring binding affinity between drug and α1-acid glycoprotein in real time by Venturi easy ambient sonic-spray ionization mass spectrometry.

PubMed

Liu, Ning; Lu, Xin; Yang, YuHan; Yao, Chen Xi; Ning, BaoMing; He, Dacheng; He, Lan; Ouyang, Jin

2015-10-01

A new approach for monitoring the binding affinity between drugs and alpha 1-acid glycoprotein in real time was developed based on a combination of drug-protein reaction followed by Venturi easy ambient sonic-spray ionization mass spectrometry determination of the free drug concentrations. A known basic drug, propranolol was used to validate the new built method. Binding constant values calculated by venturi easy ambient sonic-spray ionization mass spectrometry was in good accordance with a traditional ultrafiltration combined with high performance liquid chromatography method. Then six types of basic drugs were used as the samples to conduct the real time analysis. Upon injection of alpha 1-acid glycoprotein to the drug mixture, the ion chromatograms were extracted to show the changes in the free drug concentrations in real time. By observing the drop-out of six types of drugs during the whole binding reaction, the binding affinities of different drugs were distinguished. A volume shift validating experiment and an injection delay correcting experiment were also performed to eliminate extraneous factors and verify the reliability of our experiment. Therefore, the features of Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS) and the experimental results indicate that our technique is likely to become a powerful tool for monitoring drug-AGP binding affinity in real time. Copyright © 2015 Elsevier B.V. All rights reserved.

Lysophosphatidylcholine and amide as metabolites for detecting alzheimer disease using ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based metabonomics.

PubMed

Cui, Yu; Liu, Xiuqin; Wang, Maoqing; Liu, Liyan; Sun, Xiaohong; Ma, Lan; Xie, Wei; Wang, Chao; Tang, Sisi; Wang, Decai; Wu, Qunhong

2014-10-01

Alzheimer disease (AD) can be diagnosed by clinical and neuropsychologic tests and at autopsy, but there are no simple effective diagnostic methods for detecting biomarkers in patients at early stages of cognitive impairment. Early metabolic alterations that may facilitate AD diagnosis have not been thoroughly explored. We applied a nontargeted metabonomic approach using ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry to analyze serum and urine samples from 46 patients with AD and 36 healthy controls. Metabolite profiles were processed using multivariate analysis to identify potential metabolites, which were further confirmed using tandem mass spectrometry. Ultrahigh-performance liquid chromatography mass spectrometry methods were additionally used to quantify potentially important biomarkers. Independent samples were then selected to validate the identified biomarkers. There was a clear separation between healthy controls and AD patients; AD patient samples had disordered amino acid and phospholipid metabolism and dysregulated palmitic amide. Receiver operator characteristic curve and quantification suggested that palmitic amide, lysophosphatidylcholine (LysoPC, 18:0), LysoPC(18:2), L-glutamine, and 5-L-glutamylglycine were the optimal metabolites. In addition, areas under the curve from the palmitic amide, LysoPC(18:2), and 5-L-glutamylglycine in the validation study were 0.714, 0.996, and 0.734, respectively. These data elucidate the metabolic alterations associated with AD and suggest new biomarkers for AD diagnosis, thereby permitting early intervention designed to prevent disease progression.

mzResults: An Interactive Viewer for Interrogation and Distribution of Proteomics Results*

PubMed Central

Webber, James T.; Askenazi, Manor; Marto, Jarrod A.

2011-01-01

The growing use of mass spectrometry in the context of biomedical research has been accompanied by an increased demand for distribution of results in a format that facilitates rapid and efficient validation of claims by reviewers and other interested parties. However, the continued evolution of mass spectrometry hardware, sample preparation methods, and peptide identification algorithms complicates standardization and creates hurdles related to compliance with journal submission requirements. Moreover, the recently announced Philadelphia Guidelines (1, 2) suggest that authors provide native mass spectrometry data files in support of their peer-reviewed research articles. These trends highlight the need for data viewers and other tools that work independently of manufacturers' proprietary data systems and seamlessly connect proteomics results with original data files to support user-driven data validation and review. Based upon our recently described API1-based framework for mass spectrometry data analysis (3, 4), we created an interactive viewer (mzResults) that is built on established database standards and enables efficient distribution and interrogation of results associated with proteomics experiments, while also providing a convenient mechanism for authors to comply with data submission standards as described in the Philadelphia Guidelines. In addition, the architecture of mzResults supports in-depth queries of the native mass spectrometry files through our multiplierz software environment. We use phosphoproteomics data to illustrate the features and capabilities of mzResults. PMID:21266631

Determination of total mercury in environmental and biological samples by flow injection cold vapour atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Murphy, James; Jones, Phil; Hill, Steve J.

1996-12-01

A simple and accurate method has been developed for the determination of total mercury in environmental and biological samples. The method utilises an off-line microwave digestion stage followed by analysis using a flow injection system with detection by cold vapour atomic absorption spectrometry. The method has been validated using two certified reference materials (DORM-1 dogfish and MESS-2 estuarine sediment) and the results agreed well with the certified values. A detection limit of 0.2 ng g -1 Hg was obtained and no significant interference was observed. The method was finally applied to the determination of mercury in river sediments and canned tuna fish, and gave results in the range 0.1-3.0 mg kg -1.

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. Copyright © 2015 John Wiley & Sons, Ltd.

Development of analytical methods for multiplex bio-assay with inductively coupled plasma mass spectrometry

PubMed Central

Ornatsky, Olga I.; Kinach, Robert; Bandura, Dmitry R.; Lou, Xudong; Tanner, Scott D.; Baranov, Vladimir I.; Nitz, Mark; Winnik, Mitchell A.

2008-01-01

Advances in the development of highly multiplexed bio-analytical assays with inductively coupled plasma mass spectrometry (ICP-MS) detection are discussed. Use of novel reagents specifically designed for immunological methods utilizing elemental analysis is presented. The major steps of method development, including selection of elements for tags, validation of tagged reagents, and examples of multiplexed assays, are considered in detail. The paper further describes experimental protocols for elemental tagging of antibodies, immunostaining of live and fixed human leukemia cells, and preparation of samples for ICP-MS analysis. Quantitative analysis of surface antigens on model cell lines using a cocktail of seven lanthanide labeled antibodies demonstrated high specificity and concordance with conventional immunophenotyping. PMID:19122859

Jwalk and MNXL Web Server: Model Validation using Restraints from Crosslinking Mass Spectrometry.

PubMed

Bullock, J M A; Thalassinos, K; Topf, M

2018-05-07

Crosslinking Mass Spectrometry generates restraints that can be used to model proteins and protein complexes. Previously, we have developed two methods, to help users achieve better modelling performance from their crosslinking restraints: Jwalk, to estimate solvent accessible distances between crosslinked residues and MNXL, to assess the quality of the models based on these distances. Here we present the Jwalk and MNXL webservers, which streamline the process of validating monomeric protein models using restraints from crosslinks. We demonstrate this by using the MNXL server to filter models made of varying quality, selecting the most native-like. The webserver and source code are freely available from jwalk.ismb.lon.ac.uk and mnxl.ismb.lon.ac.uk. m.topf@cryst.bbk.ac.uk, j.bullock@cryst.bbk.ac.uk.

Confirmation of diosmetin 3-O-glucuronide as major metabolite of diosmin in humans, using micro-liquid-chromatography-mass spectrometry and ion mobility mass spectrometry.

PubMed

Silvestro, Luigi; Tarcomnicu, Isabela; Dulea, Constanta; Attili, Nageswara Rao B N; Ciuca, Valentin; Peru, Dan; Rizea Savu, Simona

2013-10-01

Diosmin is a flavonoid often administered in the treatment of chronic venous insufficiency, hemorrhoids, and related affections. Diosmin is rapidly hydrolized in the intestine to its aglicone, diosmetin, which is further metabolized to conjugates. In this study, the development and validations of three new methods for the determination of diosmetin, free and after enzymatic deconjugation, and of its potential glucuronide metabolites, diosmetin-3-O-glucuronide, diosmetin-7-O-glucuronide, and diosmetin-3,7-O-glucuronide from human plasma and urine are presented. First, the quantification of diosmetin, free and after deconjugation, was carried out by high-performance liquid chromatography coupled with tandem mass spectrometry, on an Ascentis RP-Amide column (150 × 2.1 mm, 5 μm), in reversed-phase conditions, after enzymatic digestion. Then glucuronide metabolites from plasma were separated by micro-liquid chromatography coupled with tandem mass spectrometry on a HALO C18 (50 × 0.3 mm, 2.7 μm, 90 Å) column, after solid-phase extraction. Finally, glucuronides from urine were measured using a Discovery HSF5 (100 × 2.1 mm, 5 μm) column, after simple dilution with mobile phase. The methods were validated by assessing linearity, accuracy, precision, low limit of quantification, selectivity, extraction recovery, stability, and matrix effects; results in agreement with regulatory (Food and Drug Administration and European Medicines Agency) guidelines acceptance criteria were obtained in all cases. The methods were applied to a pharmacokinetic study with diosmin (450 mg orally administered tablets). The mean C max of diosmetin in plasma was 6,049.3 ± 5,548.6 pg/mL. A very good correlation between measured diosmetin and glucuronide metabolites concentrations was obtained. Diosmetin-3-O-glucuronide was identified as a major circulating metabolite of diosmetin in plasma and in urine, and this finding was confirmed by supplementary experiments with differential ion-mobility mass spectrometry.

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).

Quantification of tamoxifen and three of its phase-I metabolites in human plasma by liquid chromatography/triple-quadrupole mass spectrometry.

PubMed

Binkhorst, Lisette; Mathijssen, Ron H J; Ghobadi Moghaddam-Helmantel, Inge M; de Bruijn, Peter; van Gelder, Teun; Wiemer, Erik A C; Loos, Walter J

2011-12-15

In view of future pharmacokinetic studies, a highly sensitive ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method has been developed for the simultaneous quantification of tamoxifen and three of its main phase I metabolites in human lithium heparinized plasma. The analytical method has been thoroughly validated in agreement with FDA recommendations. Plasma samples of 200 μl were purified by liquid-liquid extraction with 1 ml n-hexane/isopropanol, after deproteination through addition of 50 μl acetone and 50 μl deuterated internal standards in acetonitrile. Tamoxifen, N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and endoxifen were chromatographically separated on an Acquity UPLC(®) BEH C18 1.7 μm 2.1 mm×100 mm column eluted at a flow-rate of 0.300 ml/min on a gradient of 0.2mM ammonium formate and acetonitrile, both acidified with 0.1% formic acid. The overall run time of the method was 10 min, with elution times of 2.9, 3.0, 4.1 and 4.2 min for endoxifen, 4-hydroxy-tamoxifen, N-desmethyl-tamoxifen and tamoxifen, respectively. Tamoxifen and its metabolites were quantified by triple-quadrupole mass spectrometry in the positive ion electrospray ionization mode. The multiple reaction monitoring transitions were set at 372>72 (m/z) for tamoxifen, 358>58 (m/z) for N-desmethyl-tamoxifen, 388>72 (m/z) for 4-hydroxy-tamoxifen and 374>58 (m/z) for endoxifen. The analytical method was highly sensitive with the lower limit of quantification validated at 5.00 nM for tamoxifen and N-desmethyl-tamoxifen and 0.500 nM for 4-hydroxy-tamoxifen and endoxifen, which is equivalent to 1.86, 1.78, 0.194 and 0.187 ng/ml for tamoxifen, N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and endoxifen, respectively. The method was also precise and accurate, with within-run and between-run precisions within 12.0% and accuracy ranging from 89.5 to 105.3%. The method has been applied to samples from a clinical study and cross-validated with a validated LC-MS/MS method in serum. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of ribavirin in chicken muscle by quick, easy, cheap, effective, rugged and safe method and liquid chromatography-tandem mass spectrometry.

PubMed

Wu, Yin-Liang; Chen, Ruo-Xia; Zhu, Lie; Lv, Yan; Zhu, Yong; Zhao, Jian

2016-02-15

A new analytical method for the determination of ribavirin in chicken muscle using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed and validated. Samples were extracted with acidified methanol (methanol:acetic acid, 99:1, v/v). The extract was further purified by QuEChERS method using primary-secondary amine (PSA) and C18. Finally, the extract was dried by nitrogen under 45°C and reconstituted in water. The separation was performed on a Hypercarb analytical column under a gradient elution. The mobile phase was composed of water buffered with ammonium acetate (2.0mM) and acetonitrile. The proposed method was validated according to the European Commission Decision 2002/657/EC. The values of the decision limit (CCα) and the detection capability (CCβ) were 1.1 and 1.5μg/kg, respectively. The mean recoveries of ribavirin ranged from 94.2% to 99.2%. The repeatability (expressed as coefficient of variation, CVr) of the method ranged from 4.5% to 4.9% and the reproducibility (CVR) of the method ranged from 4.8% to 5.4%. The method is demonstrated to be suitable for the determination of ribavirin in chicken muscle in conformity with the current EU performance requirements through validation. The total time required for the analysis of one sample, including sample preparation, was about 45min. Copyright © 2016 Elsevier B.V. All rights reserved.

A new method for quasi-reagent-free biomonitoring of mercury in human urine.

PubMed

Schlathauer, Maria; Reitsam, Verena; Schierl, Rudolf; Leopold, Kerstin

2017-05-01

A novel analytical method for sampling and extraction of mercury (Hg) from human urine is presented in this work. The method is based on selective accumulation and separation of Hg from fresh urine sample onto active nanogold-coated silica material by highly efficient solid-phase extraction. After thermal desorption of Hg from the extractant, detection is performed by atomic fluorescence spectrometry (AFS). The feasibility and validity of the optimized, quasi-reagent-free approach was confirmed by recovery experiments in spiked real urine (recovery rate 96.13 ± 5.34%) and by comparison of found Hg concentrations in real urine samples - originating from occupationally exposed persons - with values obtained from reference methods cold vapor - atomic absorption spectrometry (CVAAS) and cold vapor - atomic fluorescence spectrometry (CV-AFS). A very good agreement of the found values reveals the validity of the proposed approach. The limit of detection (LOD) was found to be as low as 0.004 μg Hg L -1 and a high reproducibility with a relative standard deviations ≤4.2% (n = 6) is given. Moreover, storage of the samples for up to one week at an ambient temperature of 30 °C reveals no analyte losses or contamination. In conclusion, the proposed method enables easy-to-handle on-site extraction of total Hg from human urine ensuring at the same time reagent-free sample stabilization, providing quick and safe sampling, which can be performed by untrained persons. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of rivaroxaban in patient’s plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS)

PubMed Central

Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

2017-01-01

Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p < 0.001). In addition, we validated hemolytic, icteric or lipemic plasma samples for rivaroxaban measurement by HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels. PMID:28170419

Evaluation of a direct high-capacity target screening approach for urine drug testing using liquid chromatography-time-of-flight mass spectrometry.

PubMed

Saleh, Aljona; Stephanson, Niclas Nikolai; Granelli, Ingrid; Villén, Tomas; Beck, Olof

2012-11-15

In this study a rapid liquid chromatography-time-of-flight mass spectrometry method was developed, validated and applied in order to evaluate the potential of this technique for routine urine drug testing. Approximately 800 authentic patient samples were analyzed for amphetamines (amphetamine and methamphetamine), opiates (morphine, morphine-3-glucuronide, morphine-6-glucuronide, codeine and codeine-6-glucuronide) and buprenorphines (buprenorphine and buprenorphine-glucuronide) using immunochemical screening assays and mass spectrometry confirmation methods for comparison. The chromatographic application utilized a rapid gradient with high flow and a reversed phase column with 1.8 μm particles. Total analysis time was 4 min. The mass spectrometer operated with an electrospray interface in positive mode with a resolution power of >10,000 at m/z 956. The applied reporting limits were 100 ng/mL for amphetamines and opiates, and 5 ng/mL for buprenorphines, with lower limits of quantification were 2.8-41 ng/mL. Calibration curves showed a linear response with coefficients of correlation of 0.97-0.99. The intra- and interday imprecision in quantification at the reporting limits were <10% for all analytes but for buprenorphines <20%. Method validation data met performance criteria for a qualitative and quantitative method. The liquid chromatography-time-of-flight mass spectrometry method was found to be more selective than the immunochemical method by producing lower rates of false positives (0% for amphetamines and opiates; 3.2% for buprenorphines) and negatives (1.8% for amphetamines; 0.6% for opiates; 0% for buprenorphines). The overall agreement between the two screening methods was between 94.2 and 97.4%. Comparison of data with the confirmation (LC-MS) results for all individual 9 analytes showed that most deviating results were produced in samples with low levels of analytes. False negatives were mainly related to failure of detected peak to meet mass accuracy criteria (±20 mDa). False positives was related to presence of interfering peaks meeting mass accuracy and retention time criteria and occurred mainly at low levels. It is concluded that liquid chromatography-time-of-flight mass spectrometry has potential both as a complement and as replacement of immunochemical screening assays. Copyright © 2012 Elsevier B.V. All rights reserved.

Discrimination of Aspergillus isolates at the species and strain level by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting.

PubMed

Hettick, Justin M; Green, Brett J; Buskirk, Amanda D; Kashon, Michael L; Slaven, James E; Janotka, Erika; Blachere, Francoise M; Schmechel, Detlef; Beezhold, Donald H

2008-09-15

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to generate highly reproducible mass spectral fingerprints for 12 species of fungi of the genus Aspergillus and 5 different strains of Aspergillus flavus. Prior to MALDI-TOF MS analysis, the fungi were subjected to three 1-min bead beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contain abundant peaks in the range of 5 to 20kDa and may be used to discriminate between species unambiguously. A discriminant analysis using all peaks from the MALDI-TOF MS data yielded error rates for classification of 0 and 18.75% for resubstitution and cross-validation methods, respectively. If a subset of 28 significant peaks is chosen, resubstitution and cross-validation error rates are 0%. Discriminant analysis of the MALDI-TOF MS data for 5 strains of A. flavus using all peaks yielded error rates for classification of 0 and 5% for resubstitution and cross-validation methods, respectively. These data indicate that MALDI-TOF MS data may be used for unambiguous identification of members of the genus Aspergillus at both the species and strain levels.

Determination of cocaine and metabolites in hair by column-switching LC-MS-MS analysis.

PubMed

Alves, Marcela Nogueira Rabelo; Zanchetti, Gabriele; Piccinotti, Alberto; Tameni, Silvia; De Martinis, Bruno Spinosa; Polettini, Aldo

2013-07-01

A method for rapid, selective, and robust determination of cocaine (CO) and metabolites in 5-mg hair samples was developed and fully validated using a column-switching liquid chromatography-tandem mass spectrometry system (LC-MS-MS). Hair samples were decontaminated, segmented, incubated overnight in diluted HCl, and centrifuged, and the diluted (1:10 with distilled water) extracts were analyzed in positive ionization mode monitoring two reactions per analyte. Quantifier transitions were: m/z 304.2→182.2 for CO, m/z 290.1→168.1 for benzoylecgonine (BE), and m/z 318.2→196.2 for cocaethylene (CE). The lower limit of quantification (LLOQ) was set at 0.05 ng/mg for CO and CE, and 0.012 ng/mg for BE. Imprecision and inaccuracy at LLOQ were lower than 20 % for all analytes. Linearity ranged between 0.05 and 50.0 ng/mg for CO and CE and 0.012 and 12.50 ng/mg for BE. Selectivity, matrix effect, process efficiency, recovery, carryover, cross talk, and autosampler stability were also evaluated during validation. Eighteen real hair samples and five samples from a commercial proficiency testing program were comparatively examined with the proposed multidimensional chromatography coupled with tandem mass spectrometry procedure and our reference gas chromatography coupled to mass spectrometry (GC-MS) method. Compared with our reference GC-MS method, column-switching technique and the high sensitivity of the tandem mass spectrometry detection system allowed to significantly reduce sample amount (×10) with increased sensitivity (×2) and sample throughput (×4), to simplify sample preparation, and to avoid that interfering compounds and ions impaired the ionization and detection of the analytes and deteriorate the performance of the ion source.

Determination of nandrolone metabolites in human urine: comparison between liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry.

PubMed

Buiarelli, Francesca; Giannetti, Luigi; Jasionowska, Renata; Cruciani, Claudia; Neri, Bruno

2010-07-15

Nandrolone (19-nortestosterone) is an androgenic anabolic steroid illegally used as a growth-promoting agent in animal breeding and as a performance enhancer in athletics. Therefore, its use was officially banned in 1974 by the Medical Commission of the International Olympic Committee (IOC). Following nandrolone administration, the main metabolites in humans are 19-norandrosterone, 19-norethiocolanolone and 19-norepiandrosterone, and their presence in urine is the basis of detecting its abuse. The present work was undertaken to determine, in human urine, nandrolone metabolites (phase I and phase II) by developing and comparing multiresidue liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) methods. A double extraction by solid-phase extraction (SPE) was necessary for the complete elimination of the interfering compounds. The proposed methods were also tested on a real positive sample, and they allow us to determine the conjugated/free fractions ratio reducing the risk of false positive or misleading results and they should allow laboratories involved in doping control analysis to monitor the illegal use of steroids. The advantages of LC/MS/MS over GC/MS (which is the technique mainly used) include the elimination of the hydrolysis and derivatization steps: it is known that during enzymatic hydrolysis several steroids can be converted into related compounds and deconjugation is not always 100% effective. The validation parameters for the two methods were similar (limit of quantification (LOQ) <1 ng/mL and percentage coefficient of variance (CV%) <16.4), and both were able to confirm unambiguously all the analytes, thus confirming the validity of both techniques. Copyright 2010 John Wiley & Sons, Ltd.

Quantification of trans-1,4-polyisoprene in Eucommia ulmoides by fourier transform infrared spectroscopy and pyrolysis-gas chromatography/mass spectrometry.

PubMed

Takeno, Shinya; Bamba, Takeshi; Nakazawa, Yoshihisa; Fukusaki, Eiichiro; Okazawa, Atsushi; Kobayashi, Akio

2008-04-01

Commercial development of trans-1,4-polyisoprene from Eucommia ulmoides Oliver (EU-rubber) requires specific knowledge on selection of high-rubber-content lines and establishment of agronomic cultivation methods for achieving maximum EU-rubber yield. The development can be facilitated by high-throughput and highly sensitive analytical techniques for EU-rubber extraction and quantification. In this paper, we described an efficient EU-rubber extraction method, and validated that the accuracy was equivalent to that of the conventional Soxhlet extraction method. We also described a highly sensitive quantification method for EU-rubber by Fourier transform infrared spectroscopy (FT-IR) and pyrolysis-gas chromatography/mass spectrometry (PyGC/MS). We successfully applied the extraction/quantification method for study of seasonal changes in EU-rubber content and molecular weight distribution.

Simultaneous targeted analysis of trimethylamine-N-oxide, choline, betaine, and carnitine by high performance liquid chromatography tandem mass spectrometry.

PubMed

Liu, Jia; Zhao, Mingming; Zhou, Juntuo; Liu, Changjie; Zheng, Lemin; Yin, Yuxin

2016-11-01

Trimethylamine-N-oxide (TMAO) is a metabolite generated from choline, betaine and carnitine in a gut microbiota-dependent way. This molecule is associated with development of atherosclerosis and cardiovascular events. A sensitive liquid chromatographic electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed and validated for the simultaneous determination of TMAO related molecules including TMAO, betaine, choline, and carnitine in mouse plasma. Analytes are extracted after protein precipitation by methanol and subjected to LC-ESI-MS/MS without preliminary derivatization. Separation of analytes was achieved on an amide column with acetonitrile-water as the mobile phase. This method has been fully validated in this study in terms of selectivity, linearity, sensitivity, precision, accuracy, and carryover effect, and the stability of the analyte under various conditions has been confirmed. This developed method has successfully been applied to plasma samples of our mouse model. Copyright © 2016 Elsevier B.V. All rights reserved.

Porous Graphitic Carbon Liquid Chromatography-Mass Spectrometry Analysis of Drought Stress-Responsive Raffinose Family Oligosaccharides in Plant Tissues.

PubMed

Jorge, Tiago F; Florêncio, Maria H; António, Carla

2017-01-01

Drought is a major limiting factor in agriculture and responsible for dramatic crop yield losses worldwide. The adjustment of the metabolic status via accumulation of drought stress-responsive osmolytes is one of the many strategies that some plants have developed to cope with water deficit conditions. Osmolytes are highly polar compounds, analysis of whcih is difficult with typical reversed-phase chromatography. Porous graphitic carbon (PGC) has shown to be a suitable alternative to reversed-phase stationary phases for the analysis of highly polar compounds typically found in the plant metabolome. In this chapter, we describe the development and validation of a PGC-based liquid chromatography tandem mass spectrometry (LC-MS n ) method suitable for the target analysis of water-soluble carbohydrates, such as raffinose family oligosaccharides (RFOs). We present detailed information regarding PGC column equilibration, LC-MS n system operation, data analysis, and important notes to be considered during the steps of method development and validation.

Analysis and Quantitation of Glycated Hemoglobin by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

NASA Astrophysics Data System (ADS)

Hattan, Stephen J.; Parker, Kenneth C.; Vestal, Marvin L.; Yang, Jane Y.; Herold, David A.; Duncan, Mark W.

2016-03-01

Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the β-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R2 > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of ≤ 2.5%. Additional and independent measurements of glycation of the α-subunit of hemoglobin are used to validate β-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.

Development and validation of a turbulent flow chromatography and tandem mass spectrometry method for the quantitation of methotrexate and its metabolites 7-hydroxy methotrexate and DAMPA in serum

PubMed Central

Schofield, Ryan C.; Ramanathan, Lakshmi V.; Murata, Kazunori; Grace, Marie; Fleisher, Martin; Pessin, Melissa S.; Carlow, Dean C.

2016-01-01

A rapid and simple turbulent flow liquid chromatography (TFC–LC) method implementing positive heated electrospray ionization (HESI) for the accurate and precise determination of methotrexate (MTX), 7-hydroxy methotrexate (7-OH MTX), and 4-amino-4-deoxy-N10-methylpteroic acid (DAMPA) concentrations in serum was developed. MTX was isolated from serum samples (100 μL) after protein precipitation with methanol containing formic acid and internal standard (MTX-D3) followed by centrifugation. The supernatant was injected into the turbulent flow liquid chromatography which is followed by electrospray positive ionization tandem mass spectrometry (TFC–LC–MS/MS) and quantified using a six-point calibration curve. For MTX and DAMPA the assays were linear from 10 to 1000 nmol/L and for 7-OH MTX from 20 to 2000 nmol/L. Dilutions of 10, 100 and 1000-fold were validated giving a clinically reportable range of 10 nmol/L to 5 × 105 nmol/L. Within-day and between-day precisions at concentrations spanning the analytical measurement ranges were less than 10% for all three analytes. MTX, DAMPA and 7-OH MTX were sufficiently stable under all relevant analytical conditions. No significant matrix effect was observed during the method validation. The TFC–LC-MS/MS MTX method was also compared with three other clinically validated MTX assays: a dihydrofolate reductase (DHFR) inhibition assay, an immunoassay based on fluorescence polarization and a previously developed LC–MS/MS assay. PMID:26322588

Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.

PubMed

Poitevin, Eric

2012-01-01

A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula.

DEVELOPMENT OF DIOXIN TOXICITY EVALUATION METHOD IN HUMAN MILK BY ENZYME-LINKED IMMUNOSORBENT ASSAY-ASSAY VALIDATION FOR HUMAN MILK. (R825433)

EPA Science Inventory

In this study, the development of a toxicity evaluation method for dioxins in human milk by enzyme-linked immunosorbent assay (ELISA) was reported. A total of 17 human milk samples were tested by ELISA and by gas chromatography/mass spectrometry (GC/MS) to assess whether the E...

Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography–Tandem Mass Spectrometry

PubMed Central

Nahar, Limon Khatun; Cordero, Rosa Elena; Nutt, David; Lingford-Hughes, Anne; Turton, Samuel; Durant, Claire; Wilson, Sue; Paterson, Sue

2016-01-01

Abstract 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 (r2 > 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

Ethanol analysis by headspace gas chromatography with simultaneous flame-ionization and mass spectrometry detection.

PubMed

Tiscione, Nicholas B; Alford, Ilene; Yeatman, Dustin Tate; Shan, Xiaoqin

2011-09-01

Ethanol is the most frequently identified compound in forensic toxicology. Although confirmation involving mass spectrometry is desirable, relatively few methods have been published to date. A novel technique utilizing a Dean's Switch to simultaneously quantitate and confirm ethyl alcohol by flame-ionization (FID) and mass spectrometric (MS) detection after headspace sampling and gas chromatographic separation is presented. Using 100 μL of sample, the limits of detection and quantitation were 0.005 and 0.010 g/dL, respectively. The zero-order linear range (r(2) > 0.990) was determined to span the concentrations of 0.010 to 1.000 g/dL. The coefficient of variation of replicate analyses was less than 3.1%. Quantitative accuracy was within ±8%, ±6%, ±3%, and ±1.5% at concentrations of 0.010, 0.025, 0.080, and 0.300 g/dL, respectively. In addition, 1,1-difluoroethane was validated for qualitative identification by this method. The validated FID-MS method provides a procedure for the quantitation of ethyl alcohol in blood by FID with simultaneous confirmation by MS and can also be utilized as an identification method for inhalants such as 1,1-difluoroethane.

Solid phase microextraction and gas chromatography-mass spectrometry methods for residual solvent assessment in seized cocaine and heroin.

PubMed

Cabarcos, Pamela; Herbello-Hermelo, Paloma; Álvarez-Freire, Iván; Moreda-Piñeiro, Antonio; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar

2016-09-01

A simple sample pre-treatment method based on solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) has been optimized and validated for the assessment of 15 residual solvents (2-propanol, 2-methylpentane, 3-methylpentane, acetone, ethyl acetate, benzene, hexane, methylcyclohexane, methylcyclopentane, m-xylene, propyl acetate, toluene, 1,2,4-trimethylbenzene, dichloromethane, and ethylbenzene) in seized illicit cocaine and heroin. DMSO and DMF as sample diluents were found to offer the best residual solvent transference to the head space for further adsorption onto the SPME fiber, and the developed method therefore showed high sensitivity and analytical recovery. Variables affecting SPME were fully evaluated by applying an experimental design approach. Best conditions were found when using an equilibration time of 5 min at 70 °C and headspace sampling of residual solvents at the same temperature for 15 min. Method validation, performed within the requirements of international guidelines, showed excellent sensitivity, as well as intra- and inter-day precision and accuracy. The proposed methodology was applied to 96 cocaine samples and 14 heroin samples seized in Galicia (northwestern Spain) within 2013 and 2014.

Development and validation of an LC-MS/MS method for the quantification of tiamulin, trimethoprim, tylosin, sulfadiazine and sulfamethazine in medicated feed.

PubMed

Patyra, Ewelina; Nebot, Carolina; Gavilán, Rosa Elvira; Cepeda, Alberto; Kwiatek, Krzysztof

2018-05-01

A new multi-compound method for the analysis of veterinary drugs, namely tiamulin, trimethoprim, tylosin, sulfadiazine and sulfamethazine was developed and validated in medicated feeds. After extraction, the samples were centrifuged, diluted in Milli-Q water, filtered and analysed by high performance liquid chromatography coupled to tandem mass spectrometry. The separation of the analytes was performed on a biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/EC. Method performances were evaluated by the following parameters: linearity (R 2  < 0.99), precision (repeatability <14% and within-laboratory reproducibility <24%), recovery (73.58-115.21%), sensitivity, limit of detection (LOD), limit of quantification (LOQ), selectivity and expanded measurement uncertainty (k. = 2). The validated method was successfully applied to the 2 medicated feeds obtained from the interlaboratory studies and feed manufactures from Spain in August 2017. In these samples, tiamulin, tylosin and sulfamethazine were detected at the concentration levels declared by the manufacturers. The developed method can therefore be successfully used to routinely control the content and homogeneity of these antibacterial substances in medicated feed. Abbreviations AAFCO - Association of American Feed Control Officials; TYL - tylosin; TIAM - tiamulin fumarate; TRIM - trimethoprim; SDZ - sulfadiazine; SMZ - sulfamethazine; UV - ultraviolet detector; FLD - fluorescence detector; HPLC - high performance liquid chromatography; MS/MS - tandem mass spectrometry; LOD - limit of detection; LOQ - limit of quantification; CV - coefficient of variation; SD - standard deviation; U - uncertainty.

Ultra-high-performance supercritical fluid chromatography with quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS) for analysis of lignin-derived monomeric compounds in processed lignin samples.

PubMed

Prothmann, Jens; Sun, Mingzhe; Spégel, Peter; Sandahl, Margareta; Turner, Charlotta

2017-12-01

The conversion of lignin to potentially high-value low molecular weight compounds often results in complex mixtures of monomeric and oligomeric compounds. In this study, a method for the quantitative and qualitative analysis of 40 lignin-derived compounds using ultra-high-performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS) has been developed. Seven different columns were explored for maximum selectivity. Makeup solvent composition and ion source settings were optimised using a D-optimal design of experiment (DoE). Differently processed lignin samples were analysed and used for the method validation. The new UHPSFC/QTOF-MS method showed good separation of the 40 compounds within only 6-min retention time, and out of these, 36 showed high ionisation efficiency in negative electrospray ionisation mode. Graphical abstract A rapid and selective method for the quantitative and qualitative analysis of 40 lignin-derived compounds using ultra-high-performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS).

Method to determine 226Ra in small sediment samples by ultralow background liquid scintillation.

PubMed

Sanchez-Cabeza, Joan-Albert; Kwong, Laval Liong Wee; Betti, Maria

2010-08-15

(210)Pb dating of sediment cores is a widely used tool to reconstruct ecosystem evolution and historical pollution during the last century. Although (226)Ra can be determined by gamma spectrometry, this method shows severe limitations which are, among others, sample size requirements and counting times. In this work, we propose a new strategy based on the analysis of (210)Pb through (210)Po in equilibrium by alpha spectrometry, followed by the determination of (226)Ra (base or supported (210)Pb) without any further chemical purification by liquid scintillation and with a higher sample throughput. Although gamma spectrometry might still be required to determine (137)Cs as an independent tracer, the effort can then be focused only on those sections dated around 1963, when maximum activities are expected. In this work, we optimized the counting conditions, calibrated the system for changing quenching, and described the new method to determine (226)Ra in small sediment samples, after (210)Po determination, allowing a more precise determination of excess (210)Pb ((210)Pb(ex)). The method was validated with reference materials IAEA-384, IAEA-385, and IAEA-313.

Quantification of plasma myo-inositol using gas chromatography-mass spectrometry.

PubMed

Guo, Jin; Shi, Yingfei; Xu, Chengbao; Zhong, Rugang; Zhang, Feng; Zhang, Ting; Niu, Bo; Wang, Jianhua

2016-09-01

Myo-inositol (MI) deficiency is associated with an increased risk for neural tube defects (NTDs), mental disorders and metabolic diseases. We developed a gas chromatography-mass spectrometry (GC-MS) method to detect MI in human plasma, which was accurate, relatively efficient and convenient for clinical application. An external standard method was used for determination of plasma MI. Samples were analyzed by GC-MS after derivatization. The stable-isotope labeled internal standard approach was used to validate the method's accuracy. Alpha fetal protein (AFP) was detected by chemiluminescence immunoassay. The method was validated by determining the linearity, sensitivity and recovery rate. There was a good agreement between the internal standard approach and the present method. The NTD-affected pregnancies showed lower plasma MI (P=0.024) and higher AFP levels (P=0.001) than control. Maternal MI level showed a better discrimination in spina bifida subgroup, while AFP level showed a better discrimination in anencephaly subgroup after stratification analysis. We developed a sensitive and reliable method for the detection of clinical plasma MI, which might be a marker for NTDs screening, and established fundamental knowledge for clinical diagnosis and prevention for the diseases related to disturbed MI metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

Soil Sample Dissolution Development by Ultrawave Digester, Followed by Isotopic Separation and Analysis

DTIC Science & Technology

2017-01-09

uranium, americium, and thorium were analyzed, along with other transition and rare earth metals, utilizing inductively coupled plasma- mass spectrometry...inductively coupled plasma- mass spectrometry and/or alpha spectrometry, following digestion. For validation of the microwave protocol, radioactive... actinide elements. HF is a hazardous acid to work with and it is highly toxic. In this evaluation and validation, the actinides are of particular

Validation of a gas chromatography-triple quadrupole mass spectrometry method for confirmatory analysis of dioxins and dioxin-like polychlorobiphenyls in feed following new EU Regulation 709/2014.

PubMed

L'Homme, B; Scholl, G; Eppe, G; Focant, J-F

2015-01-09

The European Regulations laying down methods of sampling and analysis for the EU official control of levels of polychlorodibenzo-p-dioxins (PCDDs), polychloro-dibenzofurans (PCDFs), dioxin-like (DL) and non dioxin-like (NDL) PCBs in food and feed have been recently amended by EU Regulation Nos. 589/2014 and 709/2014. A major update is the recognition of gas chromatography (GC) triple quadrupole mass spectrometry (GC-QQQMS/MS) as a confirmatory tool for checking compliance with maximum levels (ML). These revisions have been initiated since this technology now exhibits similar performances to GC (magnetic sector) high resolution mass spectrometry (GC-HRMS). In this paper, we show a fully validated method for PCDD/Fs and DL-PCBs analysis in feed material of plant origin (vegetable oil) using GC-QQQMS/MS following the dedicated EU Regulation 709/2014. We show that individual analytical criteria (selectivity, linearity, quant/qual MRM transitions, accuracy around ML of 1.50ng WHO2005TEQ/kg, within-lab reproducibility, robustness, and background subtraction) meet the strict requirements set by the EU Regulation. We also propose a clear interpretation of instrumental limit of quantitation (iLOQ) as a 'performance-LOQ', defined in a specific way for GC-QQQMS/MS, and method limit of quantitation (mLOQ) as 'real-LOQ' that is used to report bound results. Eventually, the evaluation of measurement uncertainty, following a top-down approach and data produced with our method, demonstrates similar results than with GC-HRMS, thus offering a reliable alternative to the standard method for vegetable oil. Copyright © 2014 Elsevier B.V. All rights reserved.

Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keck, B D; Ognibene, T; Vogel, J S

2010-02-05

Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. The properties of AMS as a measurement technique are investigated here, and the parameters of method validation are shown. AMS, independent of anymore » separation technique to which it may be coupled, is shown to be accurate, linear, precise, and robust. As the sensitivity and universality of AMS is constantly being explored and expanded, this work underpins many areas of pharmaceutical development including drug metabolism as well as absorption, distribution and excretion of pharmaceutical compounds as a fundamental step in drug development. The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of {sup 14}C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). Further, accuracy was excellent between 1 and 3 percent while precision expressed as coefficient of variation is between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of carbon-14 (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with {sup 14}C corresponds to 30 fg equivalents. AMS provides an sensitive, accurate and precise method of measuring drug compounds in biological matrices.« less

Quantification of methionine and selenomethionine in biological samples using multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS).

PubMed

Vu, Dai Long; Ranglová, Karolína; Hájek, Jan; Hrouzek, Pavel

2018-05-01

Quantification of selenated amino-acids currently relies on methods employing inductively coupled plasma mass spectrometry (ICP-MS). Although very accurate, these methods do not allow the simultaneous determination of standard amino-acids, hampering the comparison of the content of selenated versus non-selenated species such as methionine (Met) and selenomethionine (SeMet). This paper reports two approaches for the simultaneous quantification of Met and SeMet. In the first approach, standard enzymatic hydrolysis employing Protease XIV was applied for the preparation of samples. The second approach utilized methanesulfonic acid (MA) for the hydrolysis of samples, either in a reflux system or in a microwave oven, followed by derivatization with diethyl ethoxymethylenemalonate. The prepared samples were then analyzed by multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS). Both approaches provided platforms for the accurate determination of selenium/sulfur substitution rate in Met. Moreover the second approach also provided accurate simultaneous quantification of Met and SeMet with a low limit of detection, low limit of quantification and wide linearity range, comparable to the commonly used gas chromatography mass spectrometry (GC-MS) method or ICP-MS. The novel method was validated using certified reference material in conjunction with the GC-MS reference method. Copyright © 2018. Published by Elsevier B.V.

[Validation of an in-house method for the determination of zinc in serum: Meeting the requirements of ISO 17025].

PubMed

Llorente Ballesteros, M T; Navarro Serrano, I; López Colón, J L

2015-01-01

The aim of this report is to propose a scheme for validation of an analytical technique according to ISO 17025. According to ISO 17025, the fundamental parameters tested were: selectivity, calibration model, precision, accuracy, uncertainty of measurement, and analytical interference. A protocol has been developed that has been applied successfully to quantify zinc in serum by atomic absorption spectrometry. It is demonstrated that our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics. Copyright © 2015 SECA. Published by Elsevier Espana. All rights reserved.

Metabolite identification and pharmacokinetic profiling of PP242, an ATP-competitive inhibitor of mTOR using ultra high-performance liquid chromatography and mass spectrometry.

PubMed

Rashid, Md Mamunur; Lee, Hyunbeom; Jung, Byung Hwa

2018-01-01

PP242 is a second generation novel selective ATP-competitive inhibitor of mTOR that displayed promising anti-cancer activity over several cancer types by inhibiting both the complexes of mTOR (mTORC1 and mTORC2). The purpose of this study is to identify the possible metabolites and to evaluate the pharmacokinetic profile of PP242 after a single oral administration to Sprague-Dawley (SD) rats. Two metabolites, including one phase I and one phase II, were identified by in vitro and in vivo studies using rat liver microsomes (RLMs) as well as rat plasma, urine and feces, respectively, through ultra high-performance liquid chromatography-linear ion trap quadrupole-orbitrap-mass spectrometry (UHPLC-LTQ-Orbitrap-MS). The major biotransformation pathways of PP242 were hydroxylation and glucuronide conjugation. Additionally, a simple and rapid quantification method was developed and validated. The method recovery was within 79.7-84.6%, whereas the matrix effect was 78.1-96.0% in all three quality control (QC) concentrations (low, medium and high) including the LLOQ. Other parameters showed acceptable results according to the US food and drug administration (FDA) guidelines for bioanalytical method validation. Afterwards, pharmacokinetic parameters were evaluated in rat plasma by successfully applying the validated method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). After a single oral administration at a dose of 5mg/kg, the maximum plasma concentration (C max ) of PP242 was 0.17±0.08μg/mL, while the elimination was moderately fast (T 1/2 : 172.18±45.54min). All of the obtained information on the metabolite identification and pharmacokinetic parameter elucidation could facilitate the further development of PP242. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantification of short chain amines in aqueous matrices using liquid chromatography electrospray ionization tandem mass spectrometry.

PubMed

Viidanoja, Jyrki

2017-01-13

A new liquid chromatography-electrospray ionization-tandem Mass Spectrometry (LC-ESI-MS/MS) method was developed for the determination of more than 20 C 1 -C 6 alkyl and alkanolamines in aqueous matrices. The method employs Hydrophilic Interaction Liquid Chromatography Multiple Reaction Monitoring (HILIC-MRM) with a ZIC-pHILIC column and four stable isotope labeled amines as internal standards for signal normalization and quantification of the amines. The method was validated using a refinery process water sample that was obtained from a cooling cycle of crude oil distillation. The averaged within run precision, between run precision and accuracy were generally within 2-10%, 1-9% and 80-120%, respectively, depending on the analyte and concentration level. Selected aqueous process samples were analyzed with the method. Copyright © 2016 Elsevier B.V. All rights reserved.

State of the art in the validation of screening methods for the control of antibiotic residues: is there a need for further development?

PubMed

Gaudin, Valérie

2017-09-01

Screening methods are used as a first-line approach to detect the presence of antibiotic residues in food of animal origin. The validation process guarantees that the method is fit-for-purpose, suited to regulatory requirements, and provides evidence of its performance. This article is focused on intra-laboratory validation. The first step in validation is characterisation of performance, and the second step is the validation itself with regard to pre-established criteria. The validation approaches can be absolute (a single method) or relative (comparison of methods), overall (combination of several characteristics in one) or criterion-by-criterion. Various approaches to validation, in the form of regulations, guidelines or standards, are presented and discussed to draw conclusions on their potential application for different residue screening methods, and to determine whether or not they reach the same conclusions. The approach by comparison of methods is not suitable for screening methods for antibiotic residues. The overall approaches, such as probability of detection (POD) and accuracy profile, are increasingly used in other fields of application. They may be of interest for screening methods for antibiotic residues. Finally, the criterion-by-criterion approach (Decision 2002/657/EC and of European guideline for the validation of screening methods), usually applied to the screening methods for antibiotic residues, introduced a major characteristic and an improvement in the validation, i.e. the detection capability (CCβ). In conclusion, screening methods are constantly evolving, thanks to the development of new biosensors or liquid chromatography coupled to tandem-mass spectrometry (LC-MS/MS) methods. There have been clear changes in validation approaches these last 20 years. Continued progress is required and perspectives for future development of guidelines, regulations and standards for validation are presented here.

Mono-isotope Prediction for Mass Spectra Using Bayes Network.

PubMed

Li, Hui; Liu, Chunmei; Rwebangira, Mugizi Robert; Burge, Legand

2014-12-01

Mass spectrometry is one of the widely utilized important methods to study protein functions and components. The challenge of mono-isotope pattern recognition from large scale protein mass spectral data needs computational algorithms and tools to speed up the analysis and improve the analytic results. We utilized naïve Bayes network as the classifier with the assumption that the selected features are independent to predict mono-isotope pattern from mass spectrometry. Mono-isotopes detected from validated theoretical spectra were used as prior information in the Bayes method. Three main features extracted from the dataset were employed as independent variables in our model. The application of the proposed algorithm to publicMo dataset demonstrates that our naïve Bayes classifier is advantageous over existing methods in both accuracy and sensitivity.

Analysis of Ethanolamines: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS888

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Vu, A; Koester, C

The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method titled 'Analysis of Diethanolamine, Triethanolamine, n-Methyldiethanolamine, and n-Ethyldiethanolamine in Water by Single Reaction Monitoring Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS): EPA Method MS888'. This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to validate and verify the analytical procedures described in 'EPA Method MS888' for analysis of themore » listed ethanolamines in aqueous samples. The gathered data from this validation study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of 'EPA Method MS888' can be determined.« less

Development and validation of two liquid chromatography-tandem mass spectrometry methods for the determination of silibinin and silibinin hemisuccinate in human plasma.

PubMed

Sala, Federica; Albares, Pablo; Colovic, Milena; Persiani, Stefano; Rovati, Lucio C

2014-01-15

To investigate the pharmacokinetics of silibinin and silibinin hemisuccinate in human plasma, two high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods were developed and validated. The methods require a small volume of sample (100μL), and the recovery of the analytes was complete with a good reproducibility (CV% 1.7-9.5), after a simple protein precipitation. Naringenin was used as internal standard. The chromatographic methods provided a good separation of diastereoisomers A and B of both silibinin and silibinin hemisuccinate onto a Chromolith Performance RP18e 100mm×3mm column, with a resolution of peaks from plasma matrix in less than 6min. The methods precision values expressed as CV% were always ≤6.2% and the accuracy was always well within the acceptable 15% range. Quantification was performed on a triple-quadrupole tandem mass spectrometer by Selected Reaction Monitoring (SRM) mode, in a negative ion mode, via electrospray ionization (ESI). The lower limit of quantitation was set at 5.0ng/mL (silibinin) and 25.0ng/mL (silibinin hemisuccinate), and the linearity was validated up to 1000.0 and 12,500.0ng/mL, for silibinin and silibinin hemisuccinate, respectively, with correlation coefficients (R(2)) of 0.991 or better. The methods were suitable for pharmacokinetic studies and were successfully applied to human plasma samples from subjects treated intravenously with Legalon(®) SIL at the dose of 20mg/kg, expressed as silibinin. Copyright © 2013 Elsevier B.V. All rights reserved.

Ultra-performance liquid chromatography tandem mass spectrometry method for the determination of AZ66, a sigma receptor ligand, in rat plasma and its application to in vivo pharmacokinetics.

PubMed

Jamalapuram, Seshulatha; Vuppala, Pradeep Kumar; Abdelazeem, Ahmed H; McCurdy, Christopher R; Avery, Bonnie A

2013-08-01

Methamphetamine abuse continues as a major problem in the USA owing to its powerful psychological addictive properties. AZ66, 3-[4-(4-cyclohexylpiperazine-1-yl)pentyl]-6-fluorobenzo[d]thiazole-2(3H)-one, an optimized sigma receptor ligand, is a promising therapeutic agent against methamphetamine. To study the in vivo pharmacokinetics of this novel sigma receptor ligand in rats, a sensitive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method was developed in rat plasma and validated. The developed method requires a small volume of plasma (100 μL) and a simple liquid-liquid extraction. The chromatographic separations were achieved in 3.3 min using an Acquity UPLC BEH Shield RP18 column. The mass spectrophotometric detection was carried out using a Waters Micromass Quattro MicroTM triple-quadrupole system. Multiple reaction monitoring was used for the quantitation with transitions m/z 406 → m/z 181 for AZ66 and m/z 448 → m/z 285 for aripiprazole. The method was validated over a concentration range of 1-3500 ng/mL and the lower limit of quantitation was determined to be 1 ng/mL. Validation of the assay demonstrated that the developed UPLC/MS/MS method was sensitive, accurate and selective for the determination of AZ66 in rat plasma. The present method has been successfully applied to an i.v. pharmacokinetic study in Sprague-Dawley rats. Copyright © 2013 John Wiley & Sons, Ltd.

A simple assay for the simultaneous determination of human plasma albendazole and albendazole sulfoxide levels by high performance liquid chromatography in tandem mass spectrometry with solid-phase extraction.

PubMed

Wojnicz, Aneta; Cabaleiro-Ocampo, Teresa; Román-Martínez, Manuel; Ochoa-Mazarro, Dolores; Abad-Santos, Francisco; Ruiz-Nuño, Ana

2013-11-15

A simple, reproducible and fast (4 min chromatogram) method of liquid chromatography in tandem with mass spectrometry (LC/MS-MS) was developed to determine simultaneously the plasma levels of albendazole (ABZ) and its metabolite albendazole sulfoxide (ABZOX) for pharmacokinetic and clinical analysis. Each plasma sample was extracted by solid phase extraction (SPE) using phenacetin as internal standard (IS). The extracted sample was eluted with a Zorbax XDB-CN column using an isocratic method. The mobile phase consisting of water with 1% acetic acid (40%, A) and MeOH (60%, B), was used at a flow rate of 1 mL/min. ABZ and ABZOX were detected and identified by mass spectrometry with electrospray ionization (ESI) in the positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 5-1000 ng/mL for ABZ and 10-1500 ng/mL (full validation) or 10-5000 ng/mL (partial validation) for ABZOX, with 5 and 10 ng/mL lower limit of quantification (LLOQ) for ABZ and ABZOX, respectively. The tests of accuracy and precision, matrix effect, extraction recovery and stability of the samples for both ABZ and ABZOX did not deviate more than 20% for the LLOQ and no more than 15% for other quality controls (QCs), according to regulatory agencies. © 2013.

Improvement and validation of a high-performance liquid chromatography in tandem mass spectrometry method for monitoring of omeprazole in plasma.

PubMed

Wojnicz, Aneta; Gil García, Ana Isabel; Román-Martínez, Manuel; Ochoa-Mazarro, Dolores; Abad-Santos, Francisco; Ruiz-Nuño, Ana

2015-06-01

Omeprazole (OME) is a proton pump inhibitor with a 58% bioavailability after a single oral dose. It is subject to marked interindividual variations and significant drug-drug interactions. The authors developed a simple and rapid method based on liquid chromatography in tandem with mass spectrometry with solid phase extraction and isotope-labeled internal standard to monitor plasma levels of OME in pharmacokinetics and drug-drug interaction studies. OME and its internal standard (OME-D3) were eluted with a Zorbax Extend C-18 rapid resolution column (4.6 × 50 mm, 3.5 μm) at 25°C, under isocratic conditions through a mobile phase consisting of 1 mM ammonium acetate, pH 8.5 (55%), and acetonitrile (45%). The flow rate was 0.8 mL/min, and the chromatogram run time was 1.2 minutes. OME was detected and quantified by liquid chromatography in tandem with mass spectrometry with positive electrospray ionization, which operates in multiple-reaction monitoring mode. The method was linear in the range of 1.5-2000 ng/mL for OME. The validation assays for accuracy and precision, matrix effect, extraction recovery, and stability of the samples for OME did not deviate more than 20% for the lower limit of quantification and no more than 15% for other quality controls. These findings are consistent with the requirements of regulatory agencies. The method enables rapid quantification of OME concentrations and can be used in pharmacokinetic and drug-drug interaction studies.

Liquid chromatography with tandem mass spectrometry for the simultaneous identification and quantification of cardiovascular drugs applied to the detection of substandard and falsified drugs.

PubMed

Bernard, Mélisande; Akrout, Wiem; Van Buu, Christelle Tran; Metz, Carole; Antignac, Marie; Yagoubi, Najet; Do, Bernard

2015-02-01

The counterfeiting of pharmaceuticals has been detected since about 1990 and has alarmingly continued to pick up steam. We have been recently involved in an evaluation program of some of the most commonly prescribed cardiovascular drugs in Africa, for analysing an important number of tablets or capsules obtained from different places in seven African countries. A reversed-phase high-performance liquid chromatography with tandem mass spectrometry method was developed and validated to simultaneously control the identity and the quantity of acenocoumarol, amlodipine, atenolol, captopril, furosemide, hydrochlorothiazide and simvastatin in tablets. Their separation was performed on a Kinetex® C(18) (100 mm × 2.1 mm inside diameter, 2.6 μm) column using a gradient elution of 20 mM ammonium formate buffer and acetonitrile (90:10 10:90 v/v) at a flow rate of 0.5 mL/min. The analytes were detected using electrospray ionisation tandem mass spectrometry in both positive and negative modes with multiple reaction monitoring. Tandem mass spectrometry fragmentation patterns of captopril, furosemide and acenocoumarol, up to now not detailed in the literature, were also studied to assist in the selection of the most relevant transitions towards the objectives. The developed method was validated as per International Conference on Harmonisation guidelines with respect to specificity, linearity, trueness, precision, limits of detection and quantification. It has been successfully applied to the control of oral forms of seven cardiovascular drugs collected in African countries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of 74 new psychoactive substances in serum using automated in-line solid-phase extraction-liquid chromatography-tandem mass spectrometry.

PubMed

Lehmann, Sabrina; Kieliba, Tobias; Beike, Justus; Thevis, Mario; Mercer-Chalmers-Bender, Katja

2017-10-01

A detailed description is given of the development and validation of a fully automated in-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method capable of detecting 90 central-stimulating new psychoactive substances (NPS) and 5 conventional amphetamine-type stimulants (amphetamine, 3,4-methylenedioxy-methamphetamine (MDMA), 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-N-ethyl-amphetamine (MDEA), methamphetamine) in serum. The aim was to apply the validated method to forensic samples. The preparation of 150μL of serum was performed by an Instrument Top Sample Preparation (ITSP)-SPE with mixed mode cation exchanger cartridges. The extracts were directly injected into an LC-MS/MS system, using a biphenyl column and gradient elution with 2mM ammonium formate/0.1% formic acid and acetonitrile/0.1% formic acid as mobile phases. The chromatographic run time amounts to 9.3min (including re-equilibration). The total cycle time is 11min, due to the interlacing between sample preparation and analysis. The method was fully validated using 69 NPS and five conventional amphetamine-type stimulants, according to the guidelines of the Society of Toxicological and Forensic Chemistry (GTFCh). The guidelines were fully achieved for 62 analytes (with a limit of detection (LOD) between 0.2 and 4μg/L), whilst full validation was not feasible for the remaining 12 analytes. For the fully validated analytes, the method achieved linearity in the 5μg/L (lower limit of quantification, LLOQ) to 250μg/L range (coefficients of determination>0.99). Recoveries for 69 of these compounds were greater than 50%, with relative standard deviations≤15%. The validated method was then tested for its capability in detecting a further 21 NPS, thus totalling 95 tested substances. An LOD between 0.4 and 1.6μg/L was obtained for these 21 additional qualitatively-measured substances. The method was subsequently successfully applied to 28 specimens from routine forensic case work, of which 7 samples were determined to be positive for NPS consumption. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrospray ionization time-of-flight mass spectrum analysis method of polyaluminum chloride flocculants.

PubMed

Feng, Chenghong; Bi, Zhe; Tang, Hongxiao

2015-01-06

Electrospray mass spectrometry has been reported as a novel technique for Al species identification, but to date, the working mechanism is not clear and no unanimous method exists for spectrum analysis of traditional Al salt flocculants, let alone for analysis of polyaluminum chloride (PAC) flocculants. Therefore, this paper introduces a novel theoretical calculation method to identify Al species from a mass spectrum, based on deducing changes in m/z (mass-to-charge ratio) and molecular formulas of oligomers in five typical PAC flocculants. The use of reference chemical species was specially proposed in the method to guarantee the uniqueness of the assigned species. The charge and mass reduction of the Al cluster was found to proceed by hydrolysis, gasification, and change of hydroxyl on the oxy bridge. The novel method was validated both qualitatively and quantitatively by comparing the results to those obtained with the (27)Al NMR spectrometry.

Enantioselective supercritical fluid chromatography-tandem mass spectrometry method for simultaneous estimation of risperidone and its 9-hydroxyl metabolites in rat plasma.

PubMed

Prasad, Thatipamula R; Joseph, Siji; Kole, Prashant; Kumar, Anoop; Subramanian, Murali; Rajagopalan, Sudha; Kr, Prabhakar

2017-11-01

Objective of the current work was to develop a 'green chemistry' compliant selective and sensitive supercritical fluid chromatography-tandem mass spectrometry method for simultaneous estimation of risperidone (RIS) and its chiral metabolites in rat plasma. Methodology & results: Agilent 1260 Infinity analytical supercritical fluid chromatography system resolved RIS and its chiral metabolites within runtime of 6 min using a gradient chromatography method. Using a simple protein precipitation sample preparation followed by mass spectrometric detection achieved a sensitivity of 0.92 nM (lower limit of quantification). With linearity over four log units (0.91-7500 nM), the method was found to be selective, accurate, precise and robust. The method was validated and was successfully applied for simultaneous estimation of RIS and 9-hydroxyrisperidone metabolites (R & S individually) after intravenous and per oral administration to rats.

New method for determination of epichlorohydrin in epoxy-coated cans by oxolane derivatization and gas chromatography-mass spectrometry.

PubMed

Sung, Jun Hyun; Lee, Young Ja; Park, Hyun Jin

2008-08-01

A new method was developed for the determination of epichlorohydrin (ECH) in food contact surface of epoxy-coated cans. The oxolane derivative, which produced by reaction of epoxy moiety in ECH with cyclopentanone in the presence of borontrifluoride-diethyletherate, was analyzed by gas chromatography (GC)/mass spectrometry (MS). 1,2-Epoxyhexane was used as internal standard (IS), which produced an oxolane derivative under the same reaction mechanism as ECH. The developed method was validated with 1 ng ml(-1) of limit of detection (LOD, surface area related 20 ng dm(-2)), >0.999 of linearity. Good precision, which was tested both in terms of intra-day repeatability and inter-day reproducibility, and 97.3-102.7% of good recoveries were obtained on three spiked levels of 5.2, 40.3 and 149.1 ng ml(-1). The excellent validation data suggests that this method is more simple, quick and effective than the official method in European Committee for Standardization (CEN) to determine the residual amount of ECH in food contact materials for food law compliance test. The residual amount of ECH for 13 epoxy-coated can samples was analyzed, and none of the samples was found to be detectable levels of ECH in epoxy-coated cans.

A rapid assay for the simultaneous determination of nicotine, cocaine and metabolites in meconium using disposable pipette extraction and gas chromatography-mass spectrometry (GC-MS).

PubMed

Mozaner Bordin, Dayanne C; Alves, Marcela N R; Cabrices, Oscar G; de Campos, Eduardo G; De Martinis, Bruno Spinosa

2014-01-01

Drug abuse by pregnant women is considered a serious public health problem worldwide. Meconium is the first excretion in newborns and has been used as an alternative matrix to evaluate in utero drug exposure. Solid phase extraction (SPE) is widely employed to prepare and clean up samples in the field of forensic analysis. Most SPE products require large volumes of solvent, which culminates in longer sample processing times and increased cost per sample. Disposable pipette extraction (DPX) tips have been used as an alternative to traditional SPE cartridges. They combine efficient and rapid extraction with reduced solvent consumption. The purpose of this study was to develop and validate a method to determine nicotine, cotinine, cocaine, benzoylecgonine, cocaethylene and methyl ester anhydroecgonine in meconium using DPX and gas chromatography-mass spectrometry (GC-MS). Validation results indicated that extraction efficiency ranged 50-98%, accuracy 92-106%, intra-assay precision 4-12% and inter-assay precision 6-12%. Linear calibration curves resulted in R(2) values >0.99, limits of detection ranged from 2.5 to 15 ng/g and the limit of quantitation from 10 to 20 ng/g. The DPX-GC-MS method was shown to selectively analyze trace concentrations of drugs in meconium samples. Finally, the developed and validated method was applied to 50 meconium samples.

Simultaneous determination of blonanserin and its four metabolites in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhou, Ying; Liu, Ming; Jiang, Ji; Wang, Hongyun; Hu, Pei

2013-11-15

A sensitive and rapid method based on ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the simultaneous determination of blonanserin, its major active metabolite (N-deethyl form) and other three metabolites (N-oxide form, Ethylenediamine form and Carboxylate form) in human plasma. Plasma samples were pre-purified by solid-phase extraction (SPE) and analyzed using a gradient chromatographic separation over an Acquity UPLC CSH C18 column. The mobile phase consisted of acetonitrile-water containing 5mM ammonium formate and 0.1% formic acid at a flow rate of 0.5mL/min. Positive electrospray ionization was employed as the ionization source in the multiple reaction monitoring (MRM) mode. The analysis time was about 3.5min. The method was fully validated over the concentration range of 0.01-1ng/mL for all analytes. The lower limit of quantification (LLOQ) was 0.01ng/mL. Inter- and intra-batch precision was less than 15% and the accuracy was within 85-115%. The mean extraction recoveries of all analytes at two concentration levels were consistent. Selectivity, matrix effect and stability were also validated. The method was applied to the pharmacokinetic study of blonanserin in Chinese healthy subjects. Copyright © 2013 Elsevier B.V. All rights reserved.

Qualitative and quantitative analysis of hyaluronan oligosaccharides with high performance thin layer chromatography using reagent-free derivatization on amino-modified silica and electrospray ionization-quadrupole time-of-flight mass spectrometry coupling on normal phase.

PubMed

Rothenhöfer, Martin; Scherübl, Rosmarie; Bernhardt, Günther; Heilmann, Jörg; Buschauer, Armin

2012-07-27

Purified oligomers of hyalobiuronic acid are indispensable tools to elucidate the physiological and pathophysiological role of hyaluronan degradation by various hyaluronidase isoenzymes. Therefore, we established and validated a novel sensitive, convenient, rapid, and cost-effective high performance thin layer chromatography (HPTLC) method for the qualitative and quantitative analysis of small saturated hyaluronan oligosaccharides consisting of 2-4 hyalobiuronic acid moieties. The use of amino-modified silica as stationary phase allows a simple reagent-free in situ derivatization by heating, resulting in a very low limit of detection (7-19 pmol per band, depending on the analyzed saturated oligosaccharide). By this derivatization procedure for the first time densitometric quantification of the analytes could be performed by HPTLC. The validated method showed a quantification limit of 37-71 pmol per band and was proven to be superior in comparison to conventional detection of hyaluronan oligosaccharides. The analytes were identified by hyphenation of normal phase planar chromatography to mass spectrometry (TLC-MS) using electrospray ionization. As an alternative to sequential techniques such as high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), the validated HPTLC quantification method can easily be automated and is applicable to the analysis of multiple samples in parallel. Copyright © 2012 Elsevier B.V. All rights reserved.

CREATININE DETERMINATION IN URINE BY LIQUID CHROMATOGRAPHY-ELECTROSPRAY IONIZATION-TANDEM MASS SPECTROMETRY METHOD.

PubMed

Dereziński, Paweł; Klupczyńska, Agnieszka; Sawicki, Wojciech; Kokot, Zenon J

2016-01-01

Creatinine determination in urine is used to estimate the completeness of the 24-h urine collection, compensation for variable diuresis and as a preliminary step in protein profiling in urine. Despite the fact that a wide range of methods of measuring creatinine level in biofluids has been developed, many of them are adversely affected by interfering substances. A new liquid chromatography-tandem mass spectrometry method for creatinine determination in urine has been developed. Chromatographic separation was performed by applying C18 column and a gradient elution. Analyses were carried out on a triple quadrupole mass spectrometer equipped with an electrospray ion source. The developed method was fully validated according to the international guidelines. The quantification range of the method was 5-1500 ng/mL, which corresponds to 1-300 mg/dL in urine. Limit of detection and quantitation were 2 and 5 ng/mL, respectively. Additionally, the comparison of creatinine determination by newly developed method to the colorimetric method was performed. The method enables the determination of creatinine in urine samples with a minimal sample preparation, excellent sensitivity and prominent selectivity. Since mass spectrometry allows to measure a number of compounds simultaneously, a future perspective would be to incorporate the determination of other clinically important compounds excreted in urine.

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

PubMed

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method validation for control determination of mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry.

PubMed

Torres, Daiane Placido; Martins-Teixeira, Maristela Braga; Cadore, Solange; Queiroz, Helena Müller

2015-01-01

A method for the determination of total mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) has been validated following international foodstuff protocols in order to fulfill the Brazilian National Residue Control Plan. The experimental parameters have been previously studied and optimized according to specific legislation on validation and inorganic contaminants in foodstuff. Linearity, sensitivity, specificity, detection and quantification limits, precision (repeatability and within-laboratory reproducibility), robustness as well as accuracy of the method have been evaluated. Linearity of response was satisfactory for the two range concentrations available on the TDA AAS equipment, between approximately 25.0 and 200.0 μg kg(-1) (square regression) and 250.0 and 2000.0 μg kg(-1) (linear regression) of mercury. The residues for both ranges were homoscedastic and independent, with normal distribution. Correlation coefficients obtained for these ranges were higher than 0.995. Limits of quantification (LOQ) and of detection of the method (LDM), based on signal standard deviation (SD) for a low-in-mercury sample, were 3.0 and 1.0 μg kg(-1), respectively. Repeatability of the method was better than 4%. Within-laboratory reproducibility achieved a relative SD better than 6%. Robustness of the current method was evaluated and pointed sample mass as a significant factor. Accuracy (assessed as the analyte recovery) was calculated on basis of the repeatability, and ranged from 89% to 99%. The obtained results showed the suitability of the present method for direct mercury measurement in fresh fish and shrimp samples and the importance of monitoring the analysis conditions for food control purposes. Additionally, the competence of this method was recognized by accreditation under the standard ISO/IEC 17025.

A sensitive and specific liquid chromatography mass spectrometry method for simultaneous determination of berberine, palmatine, coptisine, epiberberine and jatrorrhizine from Coptidis Rhizoma in rat plasma

NASA Astrophysics Data System (ADS)

Yu, Sen; Pang, Xiaoyan; Deng, Yuanxiong; Liu, Li; Liang, Yan; Liu, Xiaodong; Xie, Lin; Wang, Guangji; Wang, Xinting

2007-11-01

A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of five protoberberine alkaloids, which are berberine, palmatine, coptisine, epiberberine and jatrorrhizine, in rat plasma using tetrahydroberberine as an internal standard. Following solid-phase extraction, the analytes were separated by linear gradient elution on a Shim-pack ODS (4.6 [mu]m, 150 mm × 2.0 mm i.d.) column and analyzed in selected ion monitoring (SIM) mode with a positive electrospray ionization (ESI) interface using the respective [M]+ and [M + H]+ ions, [M]+ = 336 for berberine; 320 for coptisine; 336 for epiberberine; 338 for jatrorrhizine; 352 for palmatine and [M + H]+ = 340 for the internal standard. The method was validated over the concentration range of 0.31-20 ng mL-1 for all the five protoberberine alkaloids. Within-batch and between-batch precisions (R.S.D.%) were all within 15% and accuracy (%Er) ranged from -5 to 5%. The lower limits of quantification were 0.31 ng mL-1 for all analytes. The extraction recoveries were on average 80.8% for berberine, 67E0% for coptisine, 66.2% for epiberberine, 71.8% for jatrorrhizine and 73E2% for palmatine. The validated method was used to study the pharmacokinetic profile of the five protoberberine alkaloids in rat plasma after oral administration of Coptidis Rhizoma extract.

Development of a High-Performance Liquid Chromatography–Tandem Mass Spectrometry Method for the Identification and Quantification of CP-47,497, CP-47,497-C8 and JWH-250 in Mouse Brain

PubMed Central

Samano, Kimberly L.; Poklis, Justin L.; Lichtman, Aron H.; Poklis, Alphonse

2014-01-01

While Marijuana continues to be the most widely used illicit drug, abuse of synthetic cannabinoid (SCB) compounds in ‘Spice’ or ‘K2’ herbal incense products has emerged as a significant public health concern in many European countries and in the USA. Several of these SCBs have been declared Schedule I controlled substances but detection and quantification in biological samples remain a challenge. Therefore, we present a liquid chromatography–tandem mass spectrometry method after liquid–liquid extraction for the quantitation of CP-47,497, CP-47,497-C8 and JWH-250 in mouse brain. We report data for linearity, limit of quantification, accuracy/bias, precision, recovery, selectivity, carryover, matrix effects and stability experiments which were developed and fully validated based on Scientific Working Group for Forensic Toxicology guidelines for forensic toxicology method validation. Acceptable coefficients of variation for accuracy/bias, within- and between-run precision and selectivity were determined, with all values within ±15% of the target concentration. Validation experiments revealed degradation of CP-47, 497 and CP-47,497-C8 at different temperatures, and significant ion suppression was produced in brain for all compounds tested. The method was successfully applied to detect and quantify CP-47,497 in brains from mice demonstrating significant cannabimimetic behavioral effects as assessed by the classical tetrad paradigm. PMID:24816398

Analysis of Carbamate Pesticides: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS666

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Koester, C

The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method for analysis of aldicarb, bromadiolone, carbofuran, oxamyl, and methomyl in water by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), titled Method EPA MS666. This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to validate and verify the analytical procedures described in MS666 for analysis of carbamatemore » pesticides in aqueous samples. The gathered data from this validation study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of Method EPA MS666 can be determined.« less

Advanced Mass Spectrometric Methods for the Rapid and Quantitative Characterization of Proteomes

DOE PAGES

Smith, Richard D.

2002-01-01

Progress is reviewedmore » towards the development of a global strategy that aims to extend the sensitivity, dynamic range, comprehensiveness and throughput of proteomic measurements based upon the use of high performance separations and mass spectrometry. The approach uses high accuracy mass measurements from Fourier transform ion cyclotron resonance mass spectrometry (FTICR) to validate peptide ‘accurate mass tags’ (AMTs) produced by global protein enzymatic digestions for a specific organism, tissue or cell type from ‘potential mass tags’ tentatively identified using conventional tandem mass spectrometry (MS/MS). This provides the basis for subsequent measurements without the need for MS/ MS. High resolution capillary liquid chromatography separations combined with high sensitivity, and high resolution accurate FTICR measurements are shown to be capable of characterizing peptide mixtures of more than 10 5 components. The strategy has been initially demonstrated using the microorganisms Saccharomyces cerevisiae and Deinococcus radiodurans. Advantages of the approach include the high confidence of protein identification, its broad proteome coverage, high sensitivity, and the capability for stableisotope labeling methods for precise relative protein abundance measurements. Abbreviations : LC, liquid chromatography; FTICR, Fourier transform ion cyclotron resonance; AMT, accurate mass tag; PMT, potential mass tag; MMA, mass measurement accuracy; MS, mass spectrometry; MS/MS, tandem mass spectrometry; ppm, parts per million.« less

A Feasibility Study on Monitoring Residual Sugar and Alcohol Strength in Kiwi Wine Fermentation Using a Fiber-Optic FT-NIR Spectrometry and PLS Regression.

PubMed

Wang, Bingqian; Peng, Bangzhu

2017-02-01

This work aims to investigate the potential of fiber-optic Fourier transform-near-infrared (FT-NIR) spectrometry associated with chemometric analysis, which will be applied to monitor time-related changes in residual sugar and alcohol strength during kiwi wine fermentation. NIR calibration models for residual sugar and alcohol strength during kiwi wine fermentation were established on the FT-NIR spectra of 98 samples scanned in a fiber-optic FT-NIR spectrometer, and partial least squares regression method. The results showed that R 2 and root mean square error of cross-validation could achieve 0.982 and 3.81 g/L for residual sugar, and 0.984 and 0.34% for alcohol strength, respectively. Furthermore, crucial process information on kiwi must and wine fermentations provided by fiber-optic FT-NIR spectrometry was found to agree with those obtained from traditional chemical methods, and therefore this fiber-optic FT-NIR spectrometry can be applied as an effective and suitable alternative for analyses and monitoring of those processes. The overall results suggested that fiber-optic FT-NIR spectrometry is a promising tool for monitoring and controlling the kiwi wine fermentation process. © 2017 Institute of Food Technologists®.

Quantitative determination of rosuvastatin in human plasma by liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Xu, Dong-Hang; Ruan, Zou-Rong; Zhou, Quan; Yuan, Hong; Jiang, Bo

2006-01-01

A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated for determining rosuvastatin in human plasma, a new synthetic hydroxymethylglutaryl-coenzyme A reductase inhibitor. The analyte and internal standard (IS; cilostazol) were extracted by simple one-step liquid/liquid extraction with ether. The organic layer was separated and evaporated under a gentle stream of nitrogen at 40 degrees C. The chromatographic separation was performed on an Atlantis C18 column (2.1 mm x 150 mm, 5.0 microm) with a mobile phase consisting of 0.2% formic acid/methanol (30:70, v/v) at a flow rate of 0.20 mL/min. The analyses were carried out by multiple reaction monitoring (MRM) using the precursor-to-product combinations of m/z 482 --> 258 and m/z 370 --> 288. The areas of peaks from the analyte and the IS were used for quantification of rosuvastatin. The method was validated according to the FDA guidelines on bioanalytical method validation. Validation results indicated that the lower limit of quantification (LLOQ) was 0.2 ng/mL and the assay exhibited a linear range of 0.2-50.0 ng/mL and gave a correlation coefficient (r) of 0.9991 or better. Quality control samples (0.4, 8, 25 and 40 ng/mL) in six replicates from three different runs of analysis demonstrated an intra-assay precision (RSD) 7.97-15.94%, an inter-assay precision 3.19-15.27%, and an overall accuracy (relative error) of < 3.7%. The method can be applied to pharmacokinetic or bioequivalence studies of rosuvastatin.

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry assay quantifying vemurafenib in human plasma.

PubMed

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

2014-01-01

Vemurafenib is an inhibitor of mutated serine/threonine-protein kinase B-Raf (BRAF) and is registered as Zelboraf(®) for the treatment of adult patients with BRAF V600 mutation-positive unresectable or metastatic melanoma. To support Therapeutic Drug Monitoring (TDM) and clinical trials, we developed and validated a method for the quantification of vemurafenib in human plasma. Additionally two LC-MS systems with different detectors were tested: the TSQ Quantum Ultra and the API3000. Human plasma samples were collected in the clinic and stored at nominally -20°C. Vemurafenib was isolated from plasma by liquid-liquid extraction, separated on a C18 column with gradient elution, and analysed with triple quadrupole mass spectrometry in positive-ion mode. A stable isotope was used as internal standard for the quantification. Ranging from 1 to 100μg/ml the assay was linear with correlation coefficients (r(2)) of 0.9985 or better. Inter-assay and intra-assay accuracies were within ±7.6% of the nominal concentration; inter-assay and intra-assay precision were within ≤9.3% of the nominal concentration. In addition all results were within the acceptance criteria of the US FDA and the latest EMA guidelines for method validation for both MS detectors. In conclusion, the presented analytical method for vemurafenib in human plasma was successfully validated and the performance of the two LC-MS systems for this assay was comparable. In addition the method was successfully applied to evaluate the pharmacokinetic quantification of vemurafenib in cancer patients treated with vemurafenib. Copyright © 2013 Elsevier B.V. All rights reserved.

Harmonized Collaborative Validation of Aflatoxins and Sterigmatocystin in White Rice and Sorghum by Liquid Chromatography Coupled to Tandem Mass Spectrometry

PubMed Central

Ok, Hyun Ee; Tian, Fei; Hong, Eun Young; Paek, Ockjin; Kim, Sheen-Hee; Kim, Dongsul; Chun, Hyang Sook

2016-01-01

An interlaboratory study was performed in eight laboratories to validate a liquid chromatography–tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of aflatoxins and sterigmatocystin (STC) in white rice and sorghum (Sorghum bicolor). Fortified samples (at three different levels) of white rice and sorghum were extracted, purified through a solid-phase extraction (SPE) column, and then analyzed by LC/MS/MS. The apparent recoveries (ARs) ranged from 78.8% to 95.0% for aflatoxins and from 85.3% to 96.7% for STC. The relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) of aflatoxins were in the ranges 7.9%–33.8% and 24.4%–81.0%, respectively. For STC, the RSDr ranged from 7.1% to 40.2% and the RSDR ranged from 28.1% to 99.2%. The Horwitz ratio values for the aflatoxins and STC ranged from 0.4 to 1.2 in white rice and from 0.3 to 1.0 in sorghum, respectively. These results validated this method for the simultaneous determination of aflatoxins and STC by LC/MS/MS after SPE column cleanup. The percentages of satisfactory Z-score values (|Z| ≤ 2) were the following: for white rice, 100% for aflatoxins and STC; for sorghum, 100%, except in data from two laboratories for STC (0.3 μg/kg). This validated that the LC/MS/MS method was successfully applied for the determination of aflatoxins and STC in 20 white rice and 20 sorghum samples sourced from Korean markets. PMID:27983588

An analysis of nuclear fuel burnup in the AGR-1 TRISO fuel experiment using gamma spectrometry, mass spectrometry, and computational simulation techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harp, Jason M.; Demkowicz, Paul A.; Winston, Philip L.

AGR 1 was the first in a series of experiments designed to test US TRISO fuel under high temperature gas-cooled reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post irradiation examination (PIE) at INL and Oak Ridge National Laboratory. One component of the AGR 1 PIE is the experimental evaluation of the burnup of the fuel by two separate techniques. Gamma spectrometry was used to non destructively evaluate the burnup of all 72 of the TRISO fuel compacts that comprised the AGR 1 experiment. Two methodsmore » for evaluating burnup by gamma spectrometry were developed, one based on the Cs 137 activity and the other based on the ratio of Cs 134 and Cs 137 activities. Burnup values determined from both methods compared well with the values predicted from simulations. The highest measured burnup was 20.1% FIMA for the direct method and 20.0% FIMA for the ratio method (compared to 19.56% FIMA from simulations). An advantage of the ratio method is that the burnup of the cylindrical fuel compacts can determined in small (2.5 mm) axial increments and an axial burnup profile can be produced. Destructive chemical analysis by inductively coupled mass spectrometry (ICP MS) was then performed on selected compacts that were representative of the expected range of fuel burnups in the experiment to compare with the burnup values determined by gamma spectrometry. The compacts analyzed by mass spectrometry had a burnup range of 19.3% FIMA to 10.7% FIMA. The mass spectrometry evaluation of burnup for the four compacts agreed well with the gamma spectrometry burnup evaluations and the expected burnup from simulation. For all four compacts analyzed by mass spectrometry, the maximum range in the three experimentally determined values and the predicted value was 6% or less. Furthermore, the results confirm the accuracy of the nondestructive burnup evaluation from gamma spectrometry for TRISO fuel compacts across a burnup range of approximately 10 to 20% FIMA and also validate the approach used in the physics simulation of the AGR 1 experiment.« less

An analysis of nuclear fuel burnup in the AGR-1 TRISO fuel experiment using gamma spectrometry, mass spectrometry, and computational simulation techniques

DOE PAGES

Harp, Jason M.; Demkowicz, Paul A.; Winston, Philip L.; ...

2014-09-03

AGR 1 was the first in a series of experiments designed to test US TRISO fuel under high temperature gas-cooled reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post irradiation examination (PIE) at INL and Oak Ridge National Laboratory. One component of the AGR 1 PIE is the experimental evaluation of the burnup of the fuel by two separate techniques. Gamma spectrometry was used to non destructively evaluate the burnup of all 72 of the TRISO fuel compacts that comprised the AGR 1 experiment. Two methodsmore » for evaluating burnup by gamma spectrometry were developed, one based on the Cs 137 activity and the other based on the ratio of Cs 134 and Cs 137 activities. Burnup values determined from both methods compared well with the values predicted from simulations. The highest measured burnup was 20.1% FIMA for the direct method and 20.0% FIMA for the ratio method (compared to 19.56% FIMA from simulations). An advantage of the ratio method is that the burnup of the cylindrical fuel compacts can determined in small (2.5 mm) axial increments and an axial burnup profile can be produced. Destructive chemical analysis by inductively coupled mass spectrometry (ICP MS) was then performed on selected compacts that were representative of the expected range of fuel burnups in the experiment to compare with the burnup values determined by gamma spectrometry. The compacts analyzed by mass spectrometry had a burnup range of 19.3% FIMA to 10.7% FIMA. The mass spectrometry evaluation of burnup for the four compacts agreed well with the gamma spectrometry burnup evaluations and the expected burnup from simulation. For all four compacts analyzed by mass spectrometry, the maximum range in the three experimentally determined values and the predicted value was 6% or less. Furthermore, the results confirm the accuracy of the nondestructive burnup evaluation from gamma spectrometry for TRISO fuel compacts across a burnup range of approximately 10 to 20% FIMA and also validate the approach used in the physics simulation of the AGR 1 experiment.« less

Macro elemental analysis of food samples by nuclear analytical technique

NASA Astrophysics Data System (ADS)

Syahfitri, W. Y. N.; Kurniawati, S.; Adventini, N.; Damastuti, E.; Lestiani, D. D.

2017-06-01

Energy-dispersive X-ray fluorescence (EDXRF) spectrometry is a non-destructive, rapid, multi elemental, accurate, and environment friendly analysis compared with other detection methods. Thus, EDXRF spectrometry is applicable for food inspection. The macro elements calcium and potassium constitute important nutrients required by the human body for optimal physiological functions. Therefore, the determination of Ca and K content in various foods needs to be done. The aim of this work is to demonstrate the applicability of EDXRF for food analysis. The analytical performance of non-destructive EDXRF was compared with other analytical techniques; neutron activation analysis and atomic absorption spectrometry. Comparison of methods performed as cross checking results of the analysis and to overcome the limitations of the three methods. Analysis results showed that Ca found in food using EDXRF and AAS were not significantly different with p-value 0.9687, whereas p-value of K between EDXRF and NAA is 0.6575. The correlation between those results was also examined. The Pearson correlations for Ca and K were 0.9871 and 0.9558, respectively. Method validation using SRM NIST 1548a Typical Diet was also applied. The results showed good agreement between methods; therefore EDXRF method can be used as an alternative method for the determination of Ca and K in food samples.

Comparison of methods for extraction of ethyl carbamate from alcoholic beverages in gas chromatography/mass spectrometry analysis.

PubMed

Mirzoian, Armen; Mabud, Abdul

2006-01-01

A procedure to analyze ethyl carbamate (EC) by gas chromatography/mass spectrometry was optimized and validated. Deuterated EC (d5-EC) was added to the samples as an internal standard followed by extraction with polystyrene crosslinked polystyrene cartridges using minimal volumes of ethyl acetate. The EC response was measured in selective ion monitoring (SIM) mode and found to be linear in the range between the limit of quantitation (10 micro/L) and 1000 microg/L. EC recoveries varied from 92 to 112%, with the average value of 100 +/- 8%. The procedure compared well (r2 = 0.9970) with the existing AOAC Official Method with the added benefits of minimal solvent usage and reduced matrix interferences.

Lead screening in DBS by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry: application to newborns and pregnant women.

PubMed

Rello, Luis; Aramendía, Maite; Belarra, Miguel A; Resano, Martín

2015-01-01

DBS have become a clinical specimen especially adequate for establishing home-based collection protocols. In this work, high-resolution continuum source graphite furnace atomic absorption spectrometry is evaluated for the direct monitoring of Pb in DBS, both as a quantitative tool and a screening method. The development of the screening model is based on the establishment of the unreliability region around the threshold limits, 100 or 50 μg l(-1). More than 500 samples were analyzed to validate the model. The screening method demonstrated high sensitivity (the rate of true positives detected was always higher than 95%), an excellent LOD (1 µg l(-1)) and high throughput (10 min per sample).

Validated method for determination of bromopride in human plasma by liquid chromatography--electrospray tandem mass spectrometry: application to the bioequivalence study.

PubMed

Nazare, P; Massaroti, P; Duarte, L F; Campos, D R; Marchioretto, M A M; Bernasconi, G; Calafatti, S; Barros, F A P; Meurer, E C; Pedrazzoli, J; Moraes, L A B

2005-09-01

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method for the quantification of bromopride I in human plasma is presented. Sample preparation consisted of the addition of procainamide II as the internal standard, liquid-liquid extraction in alkaline conditions using hexane-ethyl acetate (1 : 1, v/v) as the extracting solvent, followed by centrifugation, evaporation of the solvent and sample reconstitution in acetonitrile. Both I and II (internal standard, IS) were analyzed using a C18 column and the mobile-phase acetonitrile-water (formic acid 0.1%). The eluted compounds were monitored using electrospray tandem mass spectrometry. The analyses were carried out by multiple reaction monitoring (MRM) using the parent-to-daughter combinations of m/z 344.20 > 271.00 and m/z 236.30 > 163.10. The areas of peaks from analyte and IS were used for quantification of I. The achieved limit of quantification was 1.0 ng/ml and the assay exhibited a linear dynamic range of 1-100.0 ng/ml and gave a correlation coefficient (r) of 0.995 or better. Validation results on linearity, specificity, accuracy, precision and stability, as well as application to the analysis of samples taken up to 24 h after oral administration of 10 mg of I in healthy volunteers demonstrated the applicability to bioequivalence studies.

A novel liquid chromatography Orbitrap mass spectrometry method with full scan for simultaneous determination of multiple bioactive constituents of Shenkang injection in rat tissues: Application to tissue distribution and pharmacokinetic studies.

PubMed

Yang, Jie; Sun, Zhi; Li, Duolu; Duan, Fei; Li, Zhuolun; Lu, Jingli; Shi, Yingying; Xu, Tanye; Zhang, Xiaojian

2018-06-07

Shenkang injection is a traditional Chinese formula with good curative effect on chronic renal failure. In this paper, a novel, rapid and sensitive ultra high performance liquid chromatography coupled with Q Exactive hybrid quadrupole orbitrap high resolution accurate mass spectrometry was developed and validated for simultaneous determination of seven bioactive constituents of Shenkang injection in rat plasma and tissues after intravenous administration. Acetonitrile was used as protein precipitation agent in biological samples dispose with carbamazepine as internal standard. The chromatographic separation was carried out on a C 18 column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). The MS analysis was performed in the full scan positive and negative ion mode. The lower limits of quantification for the seven analytes in rat plasma and tissues were 0.1-10 ng/mL. The validated method was successfully applied to tissue distribution and pharmacokinetic studies of Shenkang injection after intravenous administration. The results of the tissue distribution study showed that the high concentration of seven constituents were primarily in the kidney tract. This is the first time to report the application of Q-Orbitrap with full scan mass spectrometry in tissue distribution and pharmacokinetic studies of Shenkang injection. This article is protected by copyright. All rights reserved.

MALDI Orbitrap Mass Spectrometry Profiling of Dysregulated Sulfoglycosphingolipids in Renal Cell Carcinoma Tissues

NASA Astrophysics Data System (ADS)

Jirásko, Robert; Holčapek, Michal; Khalikova, Maria; Vrána, David; Študent, Vladimír; Prouzová, Zuzana; Melichar, Bohuslav

2017-08-01

Matrix-assisted laser desorption/ionization coupled with Orbitrap mass spectrometry (MALDI-Orbitrap-MS) is used for the clinical study of patients with renal cell carcinoma (RCC), as the most common type of kidney cancer. Significant changes in sulfoglycosphingolipid abundances between tumor and autologous normal kidney tissues are observed. First, sulfoglycosphingolipid species in studied RCC samples are identified using high mass accuracy full scan and tandem mass spectra. Subsequently, optimization, method validation, and statistical evaluation of MALDI-MS data for 158 tissues of 80 patients are discussed. More than 120 sulfoglycosphingolipids containing one to five hexosyl units are identified in human RCC samples based on the systematic study of their fragmentation behavior. Many of them are recorded here for the first time. Multivariate data analysis (MDA) methods, i.e., unsupervised principal component analysis (PCA) and supervised orthogonal partial least square discriminant analysis (OPLS-DA), are used for the visualization of differences between normal and tumor samples to reveal the most up- and downregulated lipids in tumor tissues. Obtained results are closely correlated with MALDI mass spectrometry imaging (MSI) and histologic staining. Important steps of the present MALDI-Orbitrap-MS approach are also discussed, such as the selection of best matrix, correct normalization, validation for semiquantitative study, and problems with possible isobaric interferences on closed masses in full scan mass spectra.

Multiresidue Method for Quantification of Sulfonamides and Trimethoprim in Tilapia Fillet by Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry Using QuEChERS for Sample Preparation.

PubMed

Nunes, Kátia S D; Assalin, Márcia R; Vallim, José H; Jonsson, Claudio M; Queiroz, Sonia C N; Reyes, Felix G R

2018-01-01

A multiresidue method for detecting and quantifying sulfonamides (sulfapyridine, sulfamerazine, sulfathiazole, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfamethoxypyridazine) and trimethoprim in tilapia fillet ( Oreochromis niloticus ) using liquid chromatography coupled to mass spectrometry was developed and validated. The sample preparation was optimized using the QuEChERS approach. The chromatographic separation was performed using a C18 column and 0.1% formic acid in water and acetonitrile as the mobile phase in the isocratic elution mode. Method validation was performed based on the Commission Decision 2002/657/EC and Brazilian guideline. The validation parameters evaluated were linearity ( r  ≥ 0.99); limits of detection (LOD) and quantification (LOQ), 1 ng·g -1 and 5 ng·g -1 , respectively; intraday and interdays precision (CV lower than 19.4%). The decision limit (CC α 102.6-120.0 ng·g -1 and 70 ng·g -1 for sulfonamides and trimethoprim, respectively) and detection capability (CC β 111.7-140.1 ng·g -1 and 89.9 ng·g -1 for sulfonamides and trimethoprim, respectively) were determined. Analyses of tilapia fillet samples from fish exposed to sulfamethazine through feed (incurred samples) were conducted in order to evaluate the method. This new method was demonstrated to be fast, sensitive, and suitable for monitoring sulfonamides and trimethoprim in tilapia fillet in health surveillance programs, as well as to be used in pharmacokinetics and residue depletion studies.

Liquid chromatography-mass spectrometry-based quantification of steroidal glycoalkaloids from Solanum xanthocarpum and effect of different extraction methods on their content.

PubMed

Paul, Atish T; Vir, Sanjay; Bhutani, K K

2008-10-24

A new liquid chromatography-mass spectrometry (LC-MS)-based method coupled with pressurized liquid extraction (PLE) as an efficient sample preparation technique has been developed for the quantification and fingerprint analysis of Solanum xanthocarpum. Optimum separations of the samples were achieved on a Waters MSC-18 XTerra column, using 0.5% (v/v) formic acid in water (A) and acetonitrile (ACN):2-propanol:formic acid (94.5:5:0.5, v/v/v) (B) as mobile phase. The separation was carried out using linear gradient elution with a flow rate of 1.0mL/min. The gradient was: 0min, 20% B; 14min, 30% B; 20min, 30% B; 27min, 60% B and the column was re-equilibrated to the initial condition (20% B) for 10min prior to next injection. The steroidal glycoalkaloids (SGAs) which are the major active constituents were isolated as pure compounds from the crude methanolic extract of S. xanthocarpum by preparative LC-MS and after characterization were used as external standards for the development and validation of the method. Extracts prepared by conventional Soxhlet extraction, PLE and ultrasonication were used for analysis. The method was validated for repeatability, precision (intra- and inter-day variation), accuracy (recovery) and sensitivity (limit of detection and limit of quantitation). The purpose of the work was to develop a validated method, which can be used for the quantification of SGAs in commercialized S. xanthocarpum products and the fingerprint analysis for their routine quality control.

Multiresidue Method for Quantification of Sulfonamides and Trimethoprim in Tilapia Fillet by Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry Using QuEChERS for Sample Preparation

PubMed Central

Nunes, Kátia S. D.; Assalin, Márcia R.; Vallim, José H.; Jonsson, Claudio M.; Queiroz, Sonia C. N.

2018-01-01

A multiresidue method for detecting and quantifying sulfonamides (sulfapyridine, sulfamerazine, sulfathiazole, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfamethoxypyridazine) and trimethoprim in tilapia fillet (Oreochromis niloticus) using liquid chromatography coupled to mass spectrometry was developed and validated. The sample preparation was optimized using the QuEChERS approach. The chromatographic separation was performed using a C18 column and 0.1% formic acid in water and acetonitrile as the mobile phase in the isocratic elution mode. Method validation was performed based on the Commission Decision 2002/657/EC and Brazilian guideline. The validation parameters evaluated were linearity (r ≥ 0.99); limits of detection (LOD) and quantification (LOQ), 1 ng·g−1 and 5 ng·g−1, respectively; intraday and interdays precision (CV lower than 19.4%). The decision limit (CCα 102.6–120.0 ng·g−1 and 70 ng·g−1 for sulfonamides and trimethoprim, respectively) and detection capability (CCβ 111.7–140.1 ng·g−1 and 89.9 ng·g−1 for sulfonamides and trimethoprim, respectively) were determined. Analyses of tilapia fillet samples from fish exposed to sulfamethazine through feed (incurred samples) were conducted in order to evaluate the method. This new method was demonstrated to be fast, sensitive, and suitable for monitoring sulfonamides and trimethoprim in tilapia fillet in health surveillance programs, as well as to be used in pharmacokinetics and residue depletion studies. PMID:29686929

On-line supercritical fluid extraction-supercritical fluid chromatography-mass spectrometry of polycyclic aromatic hydrocarbons in soil.

PubMed

Wicker, A Paige; Carlton, Doug D; Tanaka, Kenichiro; Nishimura, Masayuki; Chen, Vivian; Ogura, Tairo; Hedgepeth, William; Schug, Kevin A

2018-06-01

On-line supercritical fluid extraction - supercritical fluid chromatography - mass spectrometry (SFE-SFC-MS) has been applied for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil. The purpose of this study was to develop and validate the first on-line SFE-SFC-MS method for the quantification of PAHs in various types of soil. By coupling the sample extraction on-line with chromatography and detection, sample preparation is minimized, diminishing sample loss and contamination, and significantly decreasing the required extraction time. Parameters for on-line extraction coupled to chromatographic analysis were optimized. The method was validated for concentrations of 10-1500 ng of PAHs per gram of soil in Certified Reference Material (CRM) sediment, clay, and sand with R 2  ≥ 0.99. Limits of detection (LOD) were found in the range of 0.001-5 ng/g, and limits of quantification (LOQ) in the range of 5-15 ng/g. The method developed in this study can be effectively applied to the study of PAHs in the environment, and may lay the foundation for further applications of on-line SFE-SFC-MS. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimization of solid-phase extraction and liquid chromatography-tandem mass spectrometry for simultaneous determination of capilliposide B and its active metabolite in rat urine and feces: Overcoming nonspecific binding.

PubMed

Cheng, Zhongzhe; Zhou, Xing; Li, Wenyi; Hu, Bingying; Zhang, Yang; Xu, Yong; Zhang, Lin; Jiang, Hongliang

2016-11-30

Capilliposide B, a novel oleanane triterpenoid saponin isolated from Lysimachia capillipes Hemsl, showed significant anti-tumor activities in recent studies. To characterize the excretion of Capilliposide B, a reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of Capilliposide B and its active metabolite, Capilliposide A in rat urine and feces. Sample preparation using a solid-phase extraction procedure was optimized by acidification of samples at various degrees, providing extensive sample clean-up with a high extraction recovery. In addition, rat urinary samples were pretreated with CHAPS, an anti-adsorptive agent, for overcoming nonspecific analytes adsorption during sample storage and process. The method validation was conducted over the curve range of 10.0-5000ng/ml for both analytes. The intra- and inter-day precision and accuracy of the QC samples showed ≤11.0% RSD and -10.4-12.8% relative error. The method was successfully applied to an excretion study of Capilliposide B following intravenous administration. Copyright © 2016 Elsevier B.V. All rights reserved.

Validation and Application of an Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry Method for Yuanhuacine Determination in Rat Plasma after Pulmonary Administration: Pharmacokinetic Evaluation of a New Drug Delivery System.

PubMed

Li, Man; Liu, Xiao; Cai, Hao; Shen, Zhichun; Xu, Liu; Li, Weidong; Wu, Li; Duan, Jinao; Chen, Zhipeng

2016-12-16

Yuanhuacine was found to have significant inhibitory activity against A-549 human lung cancer cells. However, there would be serious adverse toxicity effects after systemic administration of yuanhuacine, such as by oral and intravenous ways. In order to achieve better curative effect and to alleviate the adverse toxicity effects, we tried to deliver yuanhuacine directly into the lungs. Ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was used to detect the analyte and IS. After extraction (ether:dichloromethane = 8:1), the analyte and IS were separated on a Waters BEH-C 18 column (100 mm × 2.1 mm, 1.7 μm) under a 5 min gradient elution using a mixture of acetonitrile and 0.1% formic acid aqueous solution as mobile phase at a flow rate of 0.3 mL/min. ESI positive mode was chosen for detection. The method was fully validated for its selectivity, accuracy, precision, stability, matrix effect, and extraction recovery. This new method for yuanhuacine concentration determination in rat plasma was reliable and could be applied for its preclinical and clinical monitoring purpose.

Development of water-phase derivatization followed by solid-phase microextraction and gas chromatography/mass spectrometry for fast determination of valproic acid in human plasma.

PubMed

Deng, Chunhui; Li, Ning; Ji, Jie; Yang, Bei; Duan, Gengli; Zhang, Xiangmin

2006-01-01

In this study, a simple, rapid, and sensitive method was developed and validated for the quantification of valproic acid (VPA), an antiepileptic drug, in human plasma, which was based on water-phase derivatization followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS). In the proposed method, VPA in plasma was rapidly derivatized with a mixture of isobutyl chloroformate, ethanol and pyridine under mild conditions (room temperature, aqueous medium), and the VPA ethyl ester formed was headspace-extracted and simultaneously concentrated using the SPME technique. Finally, the analyte extracted on SPME fiber was analyzed by GC/MS. The experimental parameters and method validations were studied. The optimal conditions were obtained: PDMS fiber, stirring rate of 1100 rpm, sample temperature of 80 degrees C, extraction time of 20 min, NaCl concentration of 30%. The proposed method had a limit of quantification (0.3 microg/mL), good recovery (89-97%) and precision (RSD value less than 10%). Because the proposed method combined a rapid water-phase derivatization with a fast, simple and solvent-free sample extraction and concentration technique of SPME, the sample preparation time was less than 25 min. This much shortens the whole analysis time of VPA in plasma. The validated method has been successfully used to analyze VPA in human plasma samples for application in pharmacokinetic studies. All these results show that water-phase derivatization followed by HS-SPME and GC/MS is an alternative and powerful method for fast determination of VPA in biological fluids. Copyright 2006 John Wiley & Sons, Ltd.

Development and co-validation of porcine insulin certified reference material by high-performance liquid chromatography-isotope dilution mass spectrometry.

PubMed

Wu, Liqing; Takatsu, Akiko; Park, Sang-Ryoul; Yang, Bin; Yang, Huaxin; Kinumi, Tomoya; Wang, Jing; Bi, Jiaming; Wang, Yang

2015-04-01

This article concerns the development and co-validation of a porcine insulin (pINS) certified reference material (CRM) produced by the National Institute of Metrology, People's Republic of China. Each CRM unit contained about 15 mg of purified solid pINS. The moisture content, amount of ignition residue, molecular mass, and purity of the pINS were measured. Both high-performance liquid chromatography-isotope dilution mass spectrometry and a purity deduction method were used to determine the mass fraction of the pINS. Fifteen units were selected to study the between-bottle homogeneity, and no inhomogeneity was observed. A stability study concluded that the CRM was stable for at least 12 months at -20 °C. The certified value of the CRM was (0.892 ± 0.036) g/g. A co-validation of the CRM was performed among Chinese, Japanese, and Korean laboratories under the framework of the Asian Collaboration on Reference Materials. The co-validation results agreed well with the certified value of the CRM. Consequently, the pINS CRM may be used as a calibration material or as a validation standard for pharmaceutical purposes to improve the quality of pharmaceutical products.

Analysis, fate studies and monitoring of the antifungal agent clotrimazole in the aquatic environment.

PubMed

Peschka, Manuela; Roberts, Paul H; Knepper, Thomas P

2007-10-01

The analysis and presence of clotrimazole, an antifungal agent with logK(OW) > 4, was thoroughly studied in the aquatic environment. For that reason analytical methods based on gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were developed and validated to quantify clotrimazole with limits of quantification down to 5 and 1 ng/L, respectively. Both methods were compared in an intercalibration exercise. The complete mass-spectrometric fragmentation pattern could be elucidated with the aid of quadrupole time of flight mass spectrometry. Since clotrimazole tends to adsorb to laboratory glassware, studies on its adsorption behaviour were made to ensure the appropriate handling of water samples, e.g. pH, storage time, pretreatment of sampling vessels or material of the vials used for final extracts. The phenomena of adsorption to suspended matter were investigated while analysing different waste-water samples. Application of the methods in various investigated wastewater and surface water samples demonstrated that clotrimazole could only be detected in the low nanogram per litre range of anthropogenic influenced unfiltered water samples after acidification to pH 2.

Quantitative determination of major active components in Ginkgo biloba dietary supplements by liquid chromatography/mass spectrometry.

PubMed

Ding, Shujing; Dudley, Ed; Plummer, Sue; Tang, Jiandong; Newton, Russell P; Brenton, A Gareth

2006-01-01

A reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS) method was developed and validated for the simultaneous determination of ten major active components in Ginkgo biloba extract (bilobalide, ginkgolides A, B, C, quercetin, kaempferol, isorhamnetin, rutin hydrate, quercetin-3-beta-D-glucoside and quercitrin hydrate) which have not been previously reported to be quantified in a single analysis. The ten components exhibit baseline separation in 50 min by C18 chromatography using a water/1:1 (v/v) methanol/acetonitrile gradient. Quantitation was performed using negative ESI-MS in selected ion monitoring (SIM) mode. Good reproducibility and recovery were obtained by this method. The sensitivity of both UV and different mass spectrometry modes (full scan, selected ion monitoring (SIM), and selected reaction monitoring (SRM)) were compared and both quantitation with and without internal standard were evaluated. The analysis of Ginkgo biloba commercial products showed remarkable variations in the rutin and quercetin content as well as the terpene lactone contents although all the products satisfy the conventional quality control method. Copyright 2006 John Wiley & Sons, Ltd.

Analysis of adulterants in a traditional herbal medicinal product using liquid chromatography-mass spectrometry-mass spectrometry.

PubMed

Lau, Aik-Jiang; Holmes, Michael J; Woo, Soo-On; Koh, Hwee-Ling

2003-02-26

Adulterations with synthetic drugs are common problems with herbal medicine and this can potentially cause serious adverse effects. It is therefore important to determine the presence of synthetic drugs in herbal medicine to ensure patients' safety. The objective of this study was to develop sensitive and specific methods to analyse phenylbutazone, caffeine and oxyphenbutazone present in a traditional Indonesian herbal product. Liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS) methods in the selected reaction-monitoring (SRM) mode were developed. It was found that the sample contained 0.53% w/w (n=3, RSD=7.56%) phenylbutazone and 0.04% w/w (n=3, RSD=8.39%) caffeine. This corresponded to 43.17 mg phenylbutazone and 3.23 mg caffeine in each sachet of powder. The methods were validated for linearity, precision, accuracy, LOD and LOQ. LOD and LOQ were found to be 3.69 and 12.29 ng/ml, respectively for phenylbutazone. For caffeine, the LOD and LOQ were 0.84 and 2.80 ng/ml, respectively. Oxyphenbutazone in the sample was found to be present at a level below the quantification level of 10.2 ng/ml. With better methods developed for analysis of adulterants in herbal medicine, the quality and safety of these medicines can be better controlled and regulated to ensure patients' safety.

A validated UHPLC-tandem mass spectrometry method for quantitative analysis of flavonolignans in milk thistle (Silybum marianum) extracts.

PubMed

Graf, Tyler N; Cech, Nadja B; Polyak, Stephen J; Oberlies, Nicholas H

2016-07-15

Validated methods are needed for the analysis of natural product secondary metabolites. These methods are particularly important to translate in vitro observations to in vivo studies. Herein, a method is reported for the analysis of the key secondary metabolites, a series of flavonolignans and a flavonoid, from an extract prepared from the seeds of milk thistle [Silybum marianum (L.) Gaertn. (Asteraceae)]. This report represents the first UHPLC MS-MS method validated for quantitative analysis of these compounds. The method takes advantage of the excellent resolution achievable with UHPLC to provide a complete analysis in less than 7min. The method is validated using both UV and MS detectors, making it applicable in laboratories with different types of analytical instrumentation available. Lower limits of quantitation achieved with this method range from 0.0400μM to 0.160μM with UV and from 0.0800μM to 0.160μM with MS. The new method is employed to evaluate variability in constituent composition in various commercial S. marianum extracts, and to show that storage of the milk thistle compounds in DMSO leads to degradation. Copyright © 2016 Elsevier B.V. All rights reserved.

High accuracy method for the application of isotope dilution to gas chromatography/mass spectrometric analysis of gases.

PubMed

Milton, Martin J T; Wang, Jian

2003-01-01

A new isotope dilution mass spectrometry (IDMS) method for high-accuracy quantitative analysis of gases has been developed and validated by the analysis of standard mixtures of carbon dioxide in nitrogen. The method does not require certified isotopic reference materials and does not require direct measurements of the highly enriched spike. The relative uncertainty of the method is shown to be 0.2%. Reproduced with the permission of Her Majesty's Stationery Office. Copyright Crown copyright 2003.

Characterization of mustard seeds and paste by DART ionization with time-of-flight mass spectrometry.

PubMed

Prchalová, Jana; Kovařík, František; Ševčík, Rudolf; Čížková, Helena; Rajchl, Aleš

2014-09-01

Direct analysis in real time (DART) is a novel technique with great potential for rapid screening analysis. The DART ionization method coupled with high-resolution time-of-flight mass spectrometry (TOF-MS) has been used for characterization of mustard seeds and table mustard. The possibility to use DART to analyse glucosinolates was confirmed on determination of sinalbin (4-hydroxybenzyl glucosinolate). The DART-TOF-MS method was optimized and validated. A set of samples of mustard seeds and mustard products was analyzed. High-performance liquid chromatography and DART-TOF-MS were used to determine glucosinolates in mustard seeds and compared. The correlation equation between these methods was DART = 0.797*HPLC + 6.987, R(2)  = 0.972. The DART technique seems to be a suitable method for evaluation of the quality of mustard seeds and mustard products. Copyright © 2014 John Wiley & Sons, Ltd.

Boron concentration measurements by alpha spectrometry and quantitative neutron autoradiography in cells and tissues treated with different boronated formulations and administration protocols.

PubMed

Bortolussi, Silva; Ciani, Laura; Postuma, Ian; Protti, Nicoletta; Luca Reversi; Bruschi, Piero; Ferrari, Cinzia; Cansolino, Laura; Panza, Luigi; Ristori, Sandra; Altieri, Saverio

2014-06-01

The possibility to measure boron concentration with high precision in tissues that will be irradiated represents a fundamental step for a safe and effective BNCT treatment. In Pavia, two techniques have been used for this purpose, a quantitative method based on charged particles spectrometry and a boron biodistribution imaging based on neutron autoradiography. A quantitative method to determine boron concentration by neutron autoradiography has been recently set-up and calibrated for the measurement of biological samples, both solid and liquid, in the frame of the feasibility study of BNCT. This technique was calibrated and the obtained results were cross checked with those of α spectrometry, in order to validate them. The comparisons were performed using tissues taken form animals treated with different boron administration protocols. Subsequently the quantitative neutron autoradiography was employed to measure osteosarcoma cell samples treated with BPA and with new boronated formulations. © 2013 Published by Elsevier Ltd.

Identification and quantification of flavonoids and chromes in Baeckea frutescens by using HPLC coupled with diode-array detection and quadruple time-of-flight mass spectrometry.

PubMed

Jia, Bei-Xi; Huangfu, Qian-Qian; Ren, Feng-Xiao; Jia, Lu; Zhang, Yan-Bing; Liu, Hong-Min; Yang, Jie; Wang, Qiang

2015-01-01

This article marks the first report on high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD) and quadruple time-of-flight mass spectrometry (Q-TOF/MS) for the identification and quantification of main bioactive constituents in Baeckea frutescens. In total, 24 compounds were identified or tentatively characterised based on their retention behaviours, UV profiles and MS fragment information. Furthermore, a validated method with good linearity, sensitivity, precision, stability, repeatability and accuracy was successfully applied for simultaneous determination of five flavonoids and one chromone in different plant parts of B. frutescens collected at different harvest times, and their dynamic contents revealed the appropriate harvest times. The established HPLC-DAD-Q-TOF/MS using multi-bioactive markers was proved to be a validated strategy for the quality evaluation on both raw materials and related products of B. frutescens.

Application of dispersive solid phase extraction for trace analysis of toxic chemicals in foods.

PubMed

Neely, Sarah; Martin, Jordan; da Cruz, Natalia Ferreira; Piester, Gavin; Robinson, Morgan; Okoniewski, Richard; Tran, Buu N

2018-05-29

The objectives of this study were to develop and validate a method for the identification of toxic organic chemicals, including groups of controlled substances, alkaloids and pesticides that are highly toxic and considered threats to public health. This project aims to ensure our laboratory's readiness to respond to emergencies involving our food supply in cooperation with the Food Emergency Response Network (FERN) program. The food matrices were homogenized in a blender or food processor prior to extraction with an acetonitrile-water mixture using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure. The extracts were then analyzed by either gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-electrospray tandem mass spectrometry (LC-ESI/MS/MS). Method validation was performed on a variety of food matrices including lettuce, grapes, milk, chicken, pork and beef. MDLs for the toxic compounds ranged from 0.01 to 0.66 mg/kg (ppm). The findings in this study will provide a valuable resource for the determination of toxic chemicals in food matrices for emergency response situations. Copyright © 2018. Published by Elsevier B.V.

High-sensitivity simultaneous liquid chromatography-tandem mass spectrometry assay of ethinyl estradiol and levonorgestrel in human plasma.

PubMed

Gandhi, Abhishek; Guttikar, Swati; Trivedi, Priti

2015-10-01

A sensitive and simultaneous liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of ethinyl estradiol and levonorgestrel. The analytes were extracted with methyl-tert-butyl ether: n-hexane (50:50, v/v) solvent mixture, followed by dansyl derivatization. The chromatographic separation was performed on a Kinetex C 18 (50 mm×4.6 mm, 2.6 µm) column with a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile in gradient composition. The mass transitions were monitored in electrospray positive ionization mode. The assay exhibited a linear range of 0.100-20.0 ng/mL for levonorgestrel and 4.00-500 pg/mL for ethinyl estradiol in human plasma. A run time of 9.0 min for each sample made it possible to analyze a throughput of more than 100 samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic and bioequivalence studies.

Simultaneous Determination of 13 Anticoagulant Rodenticidesin Human Blood by Liquid Chromatography-Tandem Mass Spectrometry and its Application in Three Poisoning Cases.

PubMed

Qiao, Zheng; Xiang, Ping; Shen, Baohua; Shen, Min; Yan, Hui

2018-05-01

Anticoagulant rodenticides are widely used for rodent control around the world. A rapid and sensitive method was developed and validated for the simultaneous determination of 13 anticoagulant rodenticides (coumafuryl, pindone, valone, warfarin, coumatetralyl, coumachlor, diphacinone, dicumarol, chlorophacinone, bromadiolone, difenacoum, flocoumafen, and brodifacoum) in human blood by liquid chromatography-tandem mass spectrometry. After liquid-liquid extraction, the anticoagulant rodenticides were separated on an Eclipse Plus C18 column. Linearities were observed for each analyte in blood ranging from 0.5 to 50 ng/mL, with correlation coefficients over 0.99. The limits of detection ranged from 0.01 to 0.2 ng/mL, and the limits of quantification were 0.5 ng/mL for all analytes. The intraday and interday precisions were <15%, and accuracies ranged from 80.3% to 111.0%. This validated method with high sensitivity has been applied in three anticoagulant rodenticide poisoning cases and has been used successfully in monitoring blood concentrations for months. © 2017 American Academy of Forensic Sciences.

Validation of a method for simultaneous determination of nitroimidazoles, benzimidazoles and chloramphenicols in swine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Xia, Xi; Wang, Yuanyuan; Wang, Xia; Li, Yun; Zhong, Feng; Li, Xiaowei; Huang, Yaoling; Ding, Shuangyang; Shen, Jianzhong

2013-05-31

This paper presents a sensitive and confirmatory multi-residue method for the analysis of 23 veterinary drugs and metabolites belonging to three classes (nitroimidazoles, benzimidazoles, and chloramphenicols) in porcine muscle, liver, and kidney. After extracted with ethyl acetate and basic ethyl acetate sequentially, the crude extracts were defatted with hexane and further purified using Oasis MCX solid-phase extraction cartridges. Rapid determination was carried out by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Data acquisition was performed under positive and negative mode simultaneously. Recoveries based on matrix-matched calibrations for meat, liver, and kidney ranged from 50.6 to 108.1%. The method quantification limits were in the range of 3-100ng/kg. Copyright © 2012 Elsevier B.V. All rights reserved.

Development and validation of a multiclass method for the quantification of veterinary drug residues in honey and royal jelly by liquid chromatography-tandem mass spectrometry.

PubMed

Jin, Yue; Zhang, Jinzhen; Zhao, Wen; Zhang, Wenwen; Wang, Lin; Zhou, Jinhui; Li, Yi

2017-04-15

The aim of this study was to develop an analytical method for the analysis of a wide range of veterinary drugs in honey and royal jelly. A modified sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed, followed by liquid chromatography tandem mass spectrometry determination. Use of the single sample preparation method for analysis of 42 veterinary drugs becomes more valuable because honey and royal jelly belong to completely different complex matrices. Another main advantage of the proposed method is its ability to identify and quantify 42 veterinary drugs with higher sensitivity than reference methods of China. This work has shown that the reported method was demonstrated to be convenient and reliable for the quick monitoring of veterinary drugs in honey and royal jelly samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in monosaccharides, organic acids and amino acids during Cabernet Sauvignon wine ageing based on a simultaneous analysis using gas chromatography-mass spectrometry.

PubMed

Zhang, Xin-Ke; Lan, Yi-Bin; Zhu, Bao-Qing; Xiang, Xiao-Feng; Duan, Chang-Qing; Shi, Ying

2018-01-01

Monosaccharides, organic acids and amino acids are the important flavour-related components in wines. The aim of this article is to develop and validate a method that could simultaneously analyse these compounds in wine based on silylation derivatisation and gas chromatography-mass spectrometry (GC-MS), and apply this method to the investigation of the changes of these compounds and speculate upon their related influences on Cabernet Sauvignon wine flavour during wine ageing. This work presented a new approach for wine analysis and provided more information concerning red wine ageing. This method could simultaneously quantitatively analyse 2 monosaccharides, 8 organic acids and 13 amino acids in wine. A validation experiment showed good linearity, sensitivity, reproducibility and recovery. Multiple derivatives of five amino acids have been found but their effects on quantitative analysis were negligible, except for methionine. The evolution pattern of each category was different, and we speculated that the corresponding mechanisms involving microorganism activities, physical interactions and chemical reactions had a great correlation with red wine flavours during ageing. Simultaneously quantitative analysis of monosaccharides, organic acids and amino acids in wine was feasible and reliable and this method has extensive application prospects. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Simultaneous determination of bioactive constituents in Danggui Buxue Tang for quality control by HPLC coupled with a diode array detector, an evaporative light scattering detector and mass spectrometry.

PubMed

Yi, Ling; Qi, Lian-Wen; Li, Ping; Ma, Yi-Han; Luo, Yong-Jing; Li, Hai-Yun

2007-09-01

Danggui Buxue Tang (DBT), a classical traditional Chinese formula comprising Radix Angelicae Sinensis (RAS) and Radix Astragali (RA), has been widely used to treat menopausal irregularity in Chinese women for nearly 800 years. In this study, a comprehensive analytical method of simultaneously determining the main types of bioactive constituents, eighteen in all from the formula, involving flavonoids, saponins, organic acid and some volatile compounds, was developed. This method was based on HPLC coupled to a diode array and evaporative light scattering detectors (HPLC-DAD-ELSD) on a common reverse-phase C(18) column. Liquid chromatography coupled with on-line electrospray ionization mass spectrometry (LC-ESI-MS) was also used to further validate and analyze the constituents. It was found that 0.3% aqueous formic acid and acetonitrile was the optimum mobile phase for gradient elution. This method, which showed good precision and accuracy, was successfully used to quantify the bioactive constituents in six products. As a result, the validated HPLC method, together with the LC-ESI-MS analysis, provided a new basis for assessing the quality of traditional Chinese medicinal compound preparations (TCMCPs) consisting of many bioactive components.

A newly validated and characterized spectrophotometric method for determination of a three water pollutants metal ions

NASA Astrophysics Data System (ADS)

Mohamed, Marwa E.; Frag, Eman Y. Z.; Mohamed, Mona A.

2018-01-01

A simple, fast and accurate spectrophotometric method had been developed to determine lead (II), chromium (III) and barium (II) ions in pure forms and in spiked water samples using thoron (THO) as a reagent forming colored complexes. It was found that the formed complexes absorbed maximally at 539, 540 and 538 nm for Pb(II)-THO, Cr(III)-THO and Ba(II)-THO complexes, respectively. The optimum experimental conditions for these complexes had been studied carefully. Beer's law was obeyed in the range 1-35, 1-70, and 1-45 μg mL- 1 for Pb (II), Cr(III) and Ba(II) ions with THO reagent, respectively. Different parameters such as linearity, selectivity, recovery, limits of quantification and detection, precision and accuracy were also evaluated in order to validate the proposed method. The results showed that, THO was effective in simultaneous determination of Pb(II), Cr(III) and Ba(III) ions in pure forms and in spiked water samples. Also, the results of the proposed method were compared with that obtained from atomic absorption spectrometry. The isolated solid complexes had been characterized using elemental analysis, X-ray powder diffraction (XRD), IR, mass spectrometry and TD-DFT calculations. Their biological activities were investigated against different types of bacteria and fungi organisms.

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. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Microvolume trace environmental analysis using peak-focusing online solid-phase extraction-nano-liquid chromatography-high-resolution mass spectrometry.

PubMed

Stravs, Michael A; Mechelke, Jonas; Ferguson, P Lee; Singer, Heinz; Hollender, Juliane

2016-03-01

Online solid-phase extraction was combined with nano-liquid chromatography coupled to high-resolution mass spectrometry (HRMS) for the analysis of micropollutants in environmental samples from small volumes. The method was validated in surface water, Microcystis aeruginosa cell lysate, and spent Microcystis growth medium. For 41 analytes, quantification limits of 0.1-28 ng/L (surface water) and 0.1-32 ng/L (growth medium) were obtained from only 88 μL of sample. In cell lysate, quantification limits ranged from 0.1-143 ng/L or 0.33-476 ng/g dry weight from a sample of 88 μL, or 26 μg dry weight, respectively. The method matches the sensitivity of established online and offline solid-phase extraction-liquid chromatography-mass spectrometry methods but requires only a fraction of the sample used by those techniques, and is among the first applications of nano-LC-MS for environmental analysis. The method was applied to the determination of bioconcentration in Microcystis aeruginosa in a laboratory experiment, and the benefit of coupling to HRMS was demonstrated in a transformation product screening.

Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization.

PubMed

Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

2008-10-01

Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15 per thousand, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment.

Magnetic solid phase extraction and static headspace gas chromatography-mass spectrometry method for the analysis of polycyclic aromatic hydrocarbons.

PubMed

Cai, Ying; Yan, Zhihong; Wang, Lijia; NguyenVan, Manh; Cai, Qingyun

2016-01-15

A magnetic solid phase extraction (MSPE) protocol combining a static headspace gas chromatography coupled to mass spectrometry (HS-GC-MS) method has been developed for extraction, and determination of 16 polycyclic aromatic hydrocarbons (PAHs) in drinking water samples. Magnetic nanoparticles (MNPs) were coated with 3-aminopropyltriethoxysilane and modified by cholesterol chloroformate. Transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy were used to characterize the cholesterol-functionalized sorbents, and the main parameters affecting the extraction as well as HS sampling, such as sorbent amount, extraction time, oven temperature and equilibration time have been investigated and established. Combination with HS sampling, the MSPE procedure was simple, fast and environmentally friendly, without need of any organic solvent. Method validation proved the feasibility of the developed sorbents for the quantitation of the investigated analytes at trace levels obtaining the limit of detection (S/N=3) ranging from 0.20 to 7.8 ng/L. Good values for intra and inter-day precision were obtained (RSDs ≤ 9.9%). The proposed method was successfully applied to drinking water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Sulfur-based absolute quantification of proteins using isotope dilution inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Lee, Hyun-Seok; Heun Kim, Sook; Jeong, Ji-Seon; Lee, Yong-Moon; Yim, Yong-Hyeon

2015-10-01

An element-based reductive approach provides an effective means of realizing International System of Units (SI) traceability for high-purity biological standards. Here, we develop an absolute protein quantification method using double isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS) combined with microwave-assisted acid digestion for the first time. We validated the method and applied it to certify the candidate protein certified reference material (CRM) of human growth hormone (hGH). The concentration of hGH was determined by analysing the total amount of sulfur in hGH. Next, the size-exclusion chromatography method was used with ICP-MS to characterize and quantify sulfur-containing impurities. By subtracting the contribution of sulfur-containing impurities from the total sulfur content in the hGH CRM, we obtained a SI-traceable certification value. The quantification result obtained with the present method based on sulfur analysis was in excellent agreement with the result determined via a well-established protein quantification method based on amino acid analysis using conventional acid hydrolysis combined with an ID liquid chromatography-tandem mass spectrometry. The element-based protein quantification method developed here can be generally used for SI-traceable absolute quantification of proteins, especially pure-protein standards.

Determination of four forms of vitamin B12 and other B vitamins in seawater by liquid chromatography/tandem mass spectrometry.

PubMed

Heal, Katherine R; Carlson, Laura Truxal; Devol, Allan H; Armbrust, E Virginia; Moffett, James W; Stahl, David A; Ingalls, Anitra E

2014-11-30

Vitamin B(12) is an essential nutrient for more than half of surveyed marine algae species, but methods for directly measuring this important cofactor in seawater are limited. Current mass spectrometry methods do not quantify all forms of B(12), potentially missing a significant portion of the B(12) pool. We present a method to measure vitamins B(1), B(2), B(6), B(7) and four forms of B(12) dissolved in seawater. The method entails solid-phase extraction, separation by ultra-performance liquid chromatography, and detection by triple-quadrupole tandem mass spectrometry using stable-isotope-labeled internal standards. We demonstrated the use of this method in the environment by analyzing B(12) concentrations at different depths in the Hood Canal, part of the Puget Sound estuarine system in Washington State. Recovery of vitamin B(12) forms during the preconcentration steps was >71% and the limits of detection were <0.275 pM in seawater. Standard addition calibration curves in three different seawater matrices were used to determine analytical response and to quantify samples from the environment. Hydroxocobalamin was the main form of B(12) in seawater at our field site. We developed a method for quantifying four forms of B(12) in seawater by liquid chromatography/mass spectrometry with the option of simultaneous analysis of vitamins B(1), B(2), B(6), and B(7). We validated the method and demonstrated its application in the field. Copyright © 2014 John Wiley & Sons, Ltd.

Comparison of analytical performances of inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry for trace analysis of bismuth and bismuth oxide

NASA Astrophysics Data System (ADS)

Medvedev, Nickolay S.; Shaverina, Anastasiya V.; Tsygankova, Alphiya R.; Saprykin, Anatoly I.

2018-04-01

The paper presents а comparison of analytical performances of inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) for trace analysis of high purity bismuth and bismuth oxide. Matrix effects in the ICP-MS and ICP-AES methods were studied as a function of Bi concentration, ICP power and nebulizer flow rate. For ICP-MS the strong dependence of the matrix effects versus the atomic mass of analytes was observed. For ICP-AES the minimal matrix effects were achieved for spectral lines of analytes with low excitation potentials. The optimum degree of sample dilution providing minimum values of the limits of detection (LODs) was chosen. Both methods let us to reach LODs from n·10-7 to n·10-4 wt% for more than 50 trace elements. For most elements the LODs of ICP-MS were lower in comparison to ICP-AES. Validation of accuracy of the developed techniques was performed by "added-found" experiments and by comparison of the results of ICP-MS and ICP-AES analysis of high-purity bismuth oxide.

Rapid analysis of aminoglycoside antibiotics in bovine tissues using disposable pipette extraction and ultrahigh performance liquid chromatography-tandem mass spectrometry.

PubMed

Lehotay, Steven J; Mastovska, Katerina; Lightfield, Alan R; Nuñez, Alberto; Dutko, Terry; Ng, Chilton; Bluhm, Louis

2013-10-25

A high-throughput qualitative screening and identification method for 9 aminoglycosides of regulatory interest has been developed, validated, and implemented for bovine kidney, liver, and muscle tissues. The method involves extraction at previously validated conditions, cleanup using disposable pipette extraction, and analysis by a 3 min ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. The drug analytes include neomycin, streptomycin, dihydrosptreptomycin, and spectinomycin, which have residue tolerances in bovine in the US, and kanamicin, gentamicin, apramycin, amikacin, and hygromycin, which do not have US tolerances established in bovine tissues. Tobramycin was used as an internal standard. An additional drug, paromomycin also was validated in the method, but it was dropped during implementation due to conversion of neomycin into paromomycin. Proposed fragmentation patterns for the monitored ions of each analyte were elucidated with the aid of high resolution MS using a quadrupole-time-of-flight instrument. Recoveries from spiking experiments at regulatory levels of concern showed that all analytes averaged 70-120% recoveries in all tissues, except hygromycin averaged 61% recovery. Lowest calibrated levels were as low as 0.005 μg/g in matrix extracts, which approximately corresponded to the limit of detection for screening purposes. Drug identifications at levels <0.05 μg/g were made in spiked and/or real samples for all analytes and tissues tested. Analyses of 60 samples from 20 slaughtered cattle previously screened positive for aminoglycosides showed that this method worked well in practice. The UHPLC-MS/MS method has several advantages compared to the previous microbial inhibition screening assay, especially for distinguishing individual drugs from a mixture and improving identification of gentamicin in tissue samples. Published by Elsevier B.V.

Development and Validation of a Rapid 13C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices

PubMed Central

Matsunami, Risë K.; Angelides, Kimon; Engler, David A.

2015-01-01

Background: There is currently considerable discussion about the accuracy of blood glucose concentrations determined by personal blood glucose monitoring systems (BGMS). To date, the FDA has allowed new BGMS to demonstrate accuracy in reference to other glucose measurement systems that use the same or similar enzymatic-based methods to determine glucose concentration. These types of reference measurement procedures are only comparative in nature and are subject to the same potential sources of error in measurement and system perturbations as the device under evaluation. It would be ideal to have a completely orthogonal primary method that could serve as a true standard reference measurement procedure for establishing the accuracy of new BGMS. Methods: An isotope-dilution liquid chromatography/mass spectrometry (ID-UPLC-MRM) assay was developed using 13C6-glucose as a stable isotope analogue to specifically measure glucose concentration in human plasma, and validated for use against NIST standard reference materials, and against fresh isolates of whole blood and plasma into which exogenous glucose had been spiked. Assay performance was quantified to NIST-traceable dry weight measures for both glucose and 13C6-glucose. Results: The newly developed assay method was shown to be rapid, highly specific, sensitive, accurate, and precise for measuring plasma glucose levels. The assay displayed sufficient dynamic range and linearity to measure across the range of both normal and diabetic blood glucose levels. Assay performance was measured to within the same uncertainty levels (<1%) as the NIST definitive method for glucose measurement in human serum. Conclusions: The newly developed ID UPLC-MRM assay can serve as a validated reference measurement procedure to which new BGMS can be assessed for glucose measurement performance. PMID:25986627

Development and validation of a streamlined method designed to detect residues of 62 veterinary drugs in bovine kidney using ultra-high performance liquid chromatography--tandem mass spectrometry.

PubMed

Lehotay, Steven J; Lightfield, Alan R; Geis-Asteggiante, Lucía; Schneider, Marilyn J; Dutko, Terry; Ng, Chilton; Bluhm, Louis; Mastovska, Katerina

2012-08-01

In the USA, the US Department of Agriculture's Food Safety and Inspection Service (FSIS) conducts the National Residue Program designed to monitor veterinary drug and other chemical residues in beef and other slaughtered food animals. Currently, FSIS uses a 7-plate bioassay in the laboratory to screen for antimicrobial drugs in bovine kidneys from those animals tested positive by inspectors in the slaughter establishments. The microbial inhibition bioassay has several limitations in terms of monitoring scope, sensitivity, selectivity, and analysis time. Ultra-high performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS) has many advantages over the bioassay for this application, and this study was designed to develop, evaluate, and validate a fast UHPLC-MS/MS method for antibiotics and other high-priority veterinary drugs in bovine kidney. Five existing multi-class, multi-residue methods from the literature were tested and compared, and each performed similarly. Experiments with incurred samples demonstrated that a 5-min shake of 2 g homogenized kidney with 10 ml of 4/1 (v/v) acetonitrile/water followed by simultaneous clean-up of the initial extract with 0.5 g C18 and 10 ml hexane gave a fast, simple, and effective sample preparation method for the <10 min UHPLC-MS/MS analysis. An extensive 5-day validation process demonstrated that the final method could be used to acceptably screen for 54 of the 62 drugs tested, and 50 of those met qualitative MS identification criteria. Quantification was not needed in the application, but the method gave ≥ 70% recoveries and ≤ 25% reproducibilities for 30 of the drugs. Published 2012. This article is a U.S. Government work and is in the public domain of the USA.

A novel method for the determination of glycidyl and 3-monochloropropanediol esters in fish oil by gas chromatography tandem mass spectrometry.

PubMed

Garballo-Rubio, A; Soto-Chinchilla, J; Moreno, A; Zafra-Gómez, A

2017-04-01

Today, food security is one of the most important global issues with food quality control and identification of contaminants in foods and beverages, being crucial for human health and safety. In this paper, a novel single-step method for the simultaneous determination of 3-monochloropropanediol (3-MCPD) and glycidyl esters in samples of winterized and non-winterized fish oil by using gas chromatography tandem mass spectrometry (GC-MS/MS) is validated. The method is based on alkaline hydrolysis of esters at room temperature, using only 3-MCPD-d5 as internal standard, and a derivatization step with phenylboronic acid (PBA) at 90°C. The use of GC-MS/MS results in a simplified sample treatment and improvement of the limits of quantification and precision of the analytical method with no need of additional concentration of the extracts. A backflush tee placed between two HP-5 MS UI columns (15m×0.25µm×0.25mm) was used in order to minimize matrix effects and peak shape degradation usually observed in routine analyses. The method was validated in winterized and non-winterized fish oil, achieving a limit of quantification of 100ngg -1 and 50ngg -1 for 3-MCPD and glycidol, respectively. Method validation was accomplished by comparing our laboratory results with results obtained by an accredited reference laboratory (SGS Germany GmbH) and by calculating the recoveries obtained in an assay with spiked samples. For glycidol quantification, a mathematical equation was developed in order to compensate for the partial conversion of 3-MCPD into glycidol. This expression involves the quantification of 3-MBPD-d5 generated during hydrolysis reaction. Copyright © 2016 Elsevier B.V. All rights reserved.

Tetracycline residues in royal jelly and honey by liquid chromatography tandem mass spectrometry: validation study according to Commission Decision 2002/657/EC.

PubMed

Giannetti, L; Longo, F; Buiarelli, F; Russo, M V; Neri, B

2010-09-01

A specific, sensitive and robust liquid chromatography tandem mass spectrometry method for determining oxytetracycline, tetracycline, chlortetracycline and doxycycline in royal jelly and honey samples is presented. Extraction of drug residues was performed by ammonium acetate buffer as extractant followed by a clean-up with metal chelate affinity chromatography and solid-phase extraction. Tetracycline analysis was performed using liquid chromatography-electrospray ionisation-tandem mass spectrometry. The presented method is the first validated for royal jelly and in accordance with the requirements set by Commission Decision 2002/657/EC. Recoveries of the methods, calculated spiking the samples at 5.0, 10.0, 20.0 and 30.0 μg kg(-1), were 79% to 90% for honey and 77% to 90% for royal jelly. The intra-day precision (RSD) ranged between 8.1% and 15.0% for honey and from 9.1% to 16.3% for royal jelly, while inter-day precision values were from 10.2% to 17.6% and from 10.6% to 18.4% respectively for honey and royal jelly. Linearity for the four analytes was calculated from 5.0 to 50.0 μg kg(-1). The decision limits (CCα) ranged from 6.2 to 6.4 μg kg(-1) and from 6.1 to 6.5 μg kg(-1) for honey and royal jelly, respectively. Detection capabilities values (CCβ) ranged between 7.2 and 7.7 μg kg(-1) and from 7.3 to 7.9 μg kg(-1) respectively for honey and royal jelly. The developed method is currently in use for confirmation of the official control analysis of honey and royal jelly samples.

Qualitative and quantitative analysis of poly(amidoamine) dendrimers in an aqueous matrix by liquid chromatography-electrospray ionization-hybrid quadrupole/time-of-flight mass spectrometry (LC-ESI-QTOF-MS).

PubMed

Uclés, A; Ulaszewska, M M; Hernando, M D; Ramos, M J; Herrera, S; García, E; Fernández-Alba, A R

2013-07-01

This work introduces a liquid chromatography-electrospray ionization-hybrid quadrupole/time-of-flight mass spectrometry (LC-ESI-QTOF-MS)-based method for qualitative and quantitative analysis of poly(amidoamine) (PAMAM) dendrimers of generations 0 to 3 in an aqueous matrix. The multiple charging of PAMAM dendrimers generated by means of ESI has provided key advantages in dendrimer identification by assignation of charge state through high resolution of isotopic clusters. Isotopic distribution in function of abundance of isotopes (12)C and (13)C yielded valuable and complementarity data for confident characterization. A mass accuracy below 3.8 ppm for the most abundant isotopes (diagnostic ions) provided unambiguous identification of PAMAM dendrimers. Validation of the LC-ESI-QTOF-MS method and matrix effect evaluation enabled reliable and reproducible quantification. The validation parameters, limits of quantification in the range of 0.012 to 1.73 μM, depending on the generation, good linear range (R > 0.996), repeatability (RSD < 13.4%), and reproducibility (RSD < 10.9%) demonstrated the suitability of the method for the quantification of dendrimers in aqueous matrices (water and wastewater). The added selectivity, achieved by multicharge phenomena, represents a clear advantage in screening aqueous mixtures due to the fact that the matrix had no significant effect on ionization, with what is evidenced by an absence of sensitivity loss in most generations of PAMAM dendrimers. Fig Liquid chromatography-electrospray ionization-hybrid quadrupole/time of flight mass spectrometry (LC-ESI-QTOF-MS) based method for qualitative and quantitative analysis of PAMAM dendrimers in aqueous matrix.

Brief Report: A mass spectrometry assay to simultaneously analyze ROS1 and RET fusion gene expression in non-small cell lung cancer

PubMed Central

Wijesinghe, Priyanga; Bepler, Gerold

2014-01-01

Introduction ROS1 and RET gene fusions were recently discovered in non-small cell lung cancer (NSCLC) as potential therapeutic targets with small molecule kinase inhibitors. The conventional screening methods of these fusions are time consuming and require samples of high quality and quantity. Here, we describe a novel and efficient method by coupling the power of multiplexing PCR and the sensitivity of mass spectrometry. Methods The multiplex mass spectrometry platform simultaneously tests samples for the expression of nine ROS1 and six RET fusion genes. The assay incorporates detection of wild-type exon junctions immediately upstream and downstream of the fusion junction to exclude false negative results. To flag false positives, the system also comprises two independent assays for each fusion gene junction. Results The characteristic mass spectrometric peaks of the gene fusions were obtained using engineered plasmid constructs. Specific assays targeting the wild-type gene exon junctions were validated using cDNA from lung tissue of healthy individuals. The system was further validated using cDNA derived from NSCLC cell lines that express endogenous fusion genes. The expressed ROS1-SLC34A2 and CCDC6-RET gene fusions from the NSCLC cell lines HCC78 and LC-2/ad, respectively, were accurately detected by the novel assay. The assay is extremely sensitive, capable of detecting an event in test specimens containing 0.5% positive tumors. Conclusion The novel multiplexed assay is robustly capable of detecting 15 different clinically relevant RET and ROS1 fusion variants. The benefits of this detection method include exceptionally low sample input, high cost efficiency, flexibility, and rapid turnover. PMID:25384172

Automated solid-phase extraction-liquid chromatography-tandem mass spectrometry analysis of 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in human urine specimens: application to a high-throughput urine analysis laboratory.

PubMed

Robandt, P V; Klette, K L; Sibum, M

2009-10-01

An automated solid-phase extraction coupled with liquid chromatography and tandem mass spectrometry (SPE-LC-MS-MS) method for the analysis of 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in human urine specimens was developed. The method was linear (R(2) = 0.9986) to 1000 ng/mL with no carryover evidenced at 2000 ng/mL. Limits of quantification and detection were found to be 2 ng/mL. Interrun precision was evaluated at the 15 ng/mL level over nine batches spanning 15 days (n = 45). The coefficient of variation (%CV) was found to be 5.5% over the course of the validation. Intrarun precision of a 15 ng/mL control (n = 5) ranged from 0.58% CV to 7.4% CV for the same set of analytical batches. Interference was tested using (+/-)-11-hydroxy-Delta(9)-tetrahydrocannabinol, cannabidiol, (-)-Delta(8)-tetrahydrocannabinol, and cannabinol. One hundred and nineteen specimens previously found to contain THC-COOH by a previously validated gas chromatographic mass spectrometry (GC-MS) procedure were compared to the SPE-LC-MS-MS method. Excellent agreement was found (R(2) = 0.9925) for the parallel comparison study. The automated SPE procedure eliminates the human factors of specimen handling, extraction, and derivatization, thereby reducing labor costs and rework resulting from human error or technique issues. Additionally, method runtime is greatly reduced (e.g., during parallel studies the SPE-LC-MS-MS instrument was often finished with analysis by the time the technician finished the offline SPE and derivatization procedure prior to the GC-MS analysis).

A Comparison of Tissue Spray and Lipid Extract Direct Injection Electrospray Ionization Mass Spectrometry for the Differentiation of Eutopic and Ectopic Endometrial Tissues

NASA Astrophysics Data System (ADS)

Chagovets, Vitaliy; Wang, Zhihao; Kononikhin, Alexey; Starodubtseva, Natalia; Borisova, Anna; Salimova, Dinara; Popov, Igor; Kozachenko, Andrey; Chingin, Konstantin; Chen, Huanwen; Frankevich, Vladimir; Adamyan, Leila; Sukhikh, Gennady

2018-02-01

Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts. Identified features in both cases belong to three lipid classes: phosphatidylcholines, phosphoethanolamines, and sphingomyelins. Lipids coverage is validated by hydrophilic interaction liquid chromatography with mass spectrometry of lipid extracts. Multivariate analysis of data from both methods reveals satisfactory differentiation of eutopic and ectopic endometrium tissues. Overall, our results indicate that the chemical information provided by tissue spray ionization is sufficient to allow differentiation of endometrial tissues by localization with similar reliability but higher speed than in the traditional approach relying on offline extraction.

Measurement of tamsulosin in human serum by liquid chromatography-tandem mass spectrometry.

PubMed

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

2013-07-01

A simple, sensitive and robust method to extract tamsulosin from human serum, and quantify by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated and is applicable as a measure of compliance in clinical research. Tamsulosin was extracted from human serum (100μL) via liquid-liquid extraction with methyl tert-butyl ether (2mL) following dilution with 0.1M ammonium hydroxide (100μL), achieving 99.9% analyte recovery. Internal standard, d9-finasteride, was synthesised in-house. Analyte and internal standard were separated on an Ascentis(®) Express C18 (100mm×3mm, 2.7μm) column using a gradient elution with mobile phases methanol and 2mM aqueous ammonium acetate (5:95, v/v). Total run-time was 6min. Tamsulosin was quantified using a triple quadrupole mass spectrometer operated in multi-reaction-monitoring (MRM) mode using positive electrospray ionisation. Mass transitions monitored for quantitation were: tamsulosin m/z 409→228 and d9-finasteride m/z 382→318, with the structural formulae of ions confirmed by Fourier transform ion cyclotron resonance mass spectrometry (within 10ppm). The limit of quantitation was 0.2ng/mL, and the method was validated in the linear range 0.2-50ng/mL with acceptable inter- and intra-assay precision and accuracy and stability suitable for routine laboratory practice. The method was successfully applied to samples taken from research volunteers in a clinical study of benign prostatic hyperplasia. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Liquid-liquid extraction of strongly protein bound BMS-299897 from human plasma and cerebrospinal fluid, followed by high-performance liquid chromatography/tandem mass spectrometry.

PubMed

Xue, Y J; Pursley, Janice; Arnold, Mark

2007-04-11

BMS-299897 is a gamma-secretase inhibitor that is being developed for the treatment of Alzheimer's disease. Liquid-liquid extraction (LLE), chromatographic/tandem mass spectrometry (LC/MS/MS) methods have been developed and validated for the quantitation of BMS-299897 in human plasma and cerebrospinal fluid (CSF). Both methods utilized (13)C6-BMS-299897, the stable label isotope analog, as the internal standard. For the human plasma extraction method, two incubation steps were required after the addition of 5 mM ammonium acetate and the internal standard in acetonitrile to release the analyte bound to proteins prior to LLE with toluene. For the human CSF extraction method, after the addition of 0.5 N HCl and the internal standard, CSF samples were extracted with toluene and no incubation was required. The organic layers obtained from both extraction methods were removed and evaporated to dryness. The residues were reconstituted and injected into the LC/MS/MS system. Chromatographic separation was achieved isocratically on a MetaChem C18 Hypersil BDS column (2.0 mm x 50 mm, 3 microm). The mobile phase contained 10 mM ammonium acetate pH 5 and acetonitrile. Detection was by negative ion electrospray tandem mass spectrometry. The standard curves ranged from 1 to 1000 ng/ml for human plasma and 0.25-100 ng/ml for human CSF. Both standard curves were fitted to a 1/x weighted quadratic regression model. For both methods, the intra-assay precision was within 8.2% CV, the inter-assay precision was within 5.4% CV, and assay accuracy was within +/-7.4% of the nominal values. The validation and sample analysis results demonstrated that both methods had acceptable precision and accuracy across the calibration ranges.

Simultaneous quantification of paeoniflorin, nobiletin, tangeretin, liquiritigenin, isoliquiritigenin, liquiritin and formononetin from Si-Ni-San extract in rat plasma and tissues by liquid chromatography-tandem mass spectrometry.

PubMed

Li, Tianxue; Yan, Zhixiang; Zhou, Chen; Sun, Jian; Jiang, Chuan; Yang, Xinghao

2013-08-01

In this study, a sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of seven bioactive components including paeoniflorin, nobiletin, tangeretin, liquiritigenin, isoliquiritigenin, liquiritin and formononetin in rat plasma and tissues after oral administration of Si-Ni-San extract using astragaloside IV as internal standard (IS). The plasma and tissue samples were extracted by solid-phase extraction. Chromatographic separation was accomplished on a C18 column with a multiple-step gradient elution. The quantification was obtained by scanning with multiple reaction monitoring via an electrospray ionization source that was operated by switching between the positive and negative modes in two MS/MS scan segments. Full validation of the assay was implemented. In conclusion, this method demonstrated good linearity and specificity. The lower limits of quantification for the analytes were <7.5 ng/mL. Intra- and inter-day precisions (RSD) were <12.5% and accuracy (RE) ranged from -10.2 to 7.3%. The average recoveries of the analytes from rat plasma and tissues were >65.2% and 58.6%, respectively. The validated method was further applied to the determination of actual rat plasma and tissues after oral administration of Si-Ni-San extract. The results provided a meaningful basis for the clinical application of this prescription. Copyright © 2013 John Wiley & Sons, Ltd.

Method for the Determination of Aconitum Alkaloids in Dietary Supplements and Raw Materials by Reversed-Phase Liquid Chromatography with Ultraviolet Detection and Confirmation by Tandem Mass Spectrometry: Single-Laboratory Validation

PubMed Central

Tang, Wai-Tong; Wong, Sui-Kay; Law, Tin-Yau; Pang, Kwok-Chu; Sin, Della; Tam, Yin-King

2008-01-01

A study of single-laboratory validation (SLV) of a reversed-phase liquid Chromatography (RP-LC) method was conducted for the determination of diester-diterpene Aconitum alkaloids, viz., aconitine, mesaconitine, and hypaconitine, in a variety of dietary supplements, including single-arid multiple-ingredient dry powder extracts, pills, capsules, and raw materials. The Aconitum alkaloids in the samples were extracted by diethyl ether in the presence of ammonia. After cleanup with solid-phase extraction to remove the matrix interferences, the alkaloids were determined by RP-LC with UV detection at 235 nm, and the results were confirmed by tandem mass Spectrometry. The linear responses for aconitine, mesaconitine, and hypaconitine based on the present LC system ranged from 0.5 to 200 μg/mL. Relative standard deviations of 2.0 to 6.9% were obtained from duplicate analysis of 6 test materials of different matrixes for the 3 Aconitum alkaloids performed by 2 analysts on 5 different days. The recoveries determined for supplements and raw materials spiked with 3 Aconitum alkaloids at levels of 2.5–10 μg/g were in the range of 86–99%. In view of the attainment of satisfactory results for accuracy, precision, and recovery in the SLV study, it is recommended that the method validation process proceed to a collaborative study. PMID:17225594

Analysis of nifedipine in human plasma and amniotic fluid by liquid chromatography-tandem mass spectrometry and its application to clinical pharmacokinetics in hypertensive pregnant women.

PubMed

Filgueira, Gabriela Campos de Oliveira; Filgueira, Osmany Alberto Silva; Carvalho, Daniela Miarelli; Marques, Maria Paula; Moisés, Elaine Christine Dantas; Duarte, Geraldo; Lanchote, Vera Lucia; Cavalli, Ricardo Carvalho

2015-07-01

Nifedipine is a dihydropyridine calcium channel blocker used for the treatment of hypertension in pregnant women. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for analysis of nifedipine in human plasma and amniotic fluid. Separation of nifedipine and nitrendipine (IS) was performed using a LiChroCART(®) RP-Select B column and a mixture of water:acetonitrile:glacial acetic acid (30:70:0.5 v/v) as the mobile phase. Aliquots of 500μL of biological samples were extracted at pH 13 using dichloromethane:n-pentane (3:7 v/v). The validated method was applied to a study of the pharmacokinetics of nifedipine in human plasma and amniotic fluid samples collected up to 12h after administration of the last slow-release nifedipine (20mg/12h) dose to 12 hypertensive pregnant women. The estimated pharmacokinetic parameters of nifedipine showed a mean AUC(0-12) of 250.2ngh/mL, ClT/F of 89.2L/h, Vd/F of 600.0L and t1/2 5.1h. The mean amniotic fluid/plasma concentration ratio was 0.05. The methods proved to be highly sensitive by showing a lower quantification limit of 0.1ng/mL for both matrices. And this study reports for the first time the complete development and validation of the method to quantify nifedipine in amniotic fluid using LC-MS-MS. Copyright © 2015 Elsevier B.V. All rights reserved.

FIXED DOSE COMBINATIONS WITH SELECTIVE BETA-BLOCKERS: QUANTITATIVE DETERMINATION IN BIOLOGICAL FLUIDS.

PubMed

Mahu, Ştefania Corina; Hăncianu, Monica; Agoroaei, Luminiţa; Grigoriu, Ioana Cezara; Strugaru, Anca Monica; Butnaru, Elena

2015-01-01

Hypertension is one of the most common causes of death, a complex and incompletely controlled disease for millions of patients. Metoprolol, bisoprolol, nebivolol and atenolol are selective beta-blockers frequently used in the management of arterial hypertension, alone or in fixed combination with other substances. This study presents the most used analytical methods for simultaneous determination in biological fluids of fixed combinations containing selective beta-blockers. Articles in Pub-Med, Science Direct and Wiley Journals databases published between years 2004-2014 were reviewed. Methods such as liquid chromatography--mass spectrometry--mass spectrometry (LC-MS/MS), high performance liquid chromatography (HPLC) or high performance liquid chromatography--mass spectrometry (HPLC-MS) were used for determination of fixed combination with beta-blockers in human plasma, rat plasma and human breast milk. LC-MS/MS method was used for simultaneous determination of fixed combinations of metoprolol with simvastatin, hydrochlorothiazide or ramipril, combinations of nebivolol and valsartan, or atenolol and amlodipine. Biological samples were processed by protein precipitation techniques or by liquid-liquid extraction. For the determination of fixed dose combinations of felodipine and metoprolol in rat plasma liquid chromatography--electrospray ionization--mass spectrometry (LC-ESI-MS/MS) was applied, using phenacetin as internal standard. HPLC-MS method was applied for the determination of bisoprolol and hydrochlorothiazide in human plasma. For the determination of atenolol and chlorthalidone from human breast milk and human plasma the HPLC method was used. The analytical methods were validated according to the specialized guidelines, and were applied to biological samples, thing that confirms the permanent concern of researchers in this field.

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. Copyright © 2014. Published by Elsevier B.V.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples.

PubMed

Gerace, E; Salomone, A; Abbadessa, G; Racca, S; Vincenti, M

2012-02-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid-liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples

PubMed Central

Gerace, E.; Salomone, A.; Abbadessa, G.; Racca, S.; Vincenti, M.

2011-01-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid–liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration. PMID:29403714

A fully validated method for the determination of lacosamide in human plasma using gas chromatography with mass spectrometry: application for therapeutic drug monitoring.

PubMed

Nikolaou, Panagiota; Papoutsis, Ioannis; Spiliopoulou, Chara; Voudris, Constantinos; Athanaselis, Sotiris

2015-01-01

A simple gas chromatographic method with mass spectrometry detection was developed and validated for the determination of lacosamide in human plasma. Lacosamide and the internal standard, levetiracetam-d6, were extracted from 200 μL plasma, by a solid-phase extraction through HF Bond Elut C18 columns, and derivatized using N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide with 1% tert-butyldimethylsilylchloride in acetonitrile. The limit of quantification was found to be 0.20 μg/mL and the assay was linear up to 20.0 μg/mL with correlation coefficient ≥0.994. The intra- and interday precision values were <4.1% in terms of relative standard deviation (%) and the values of intra- and interday accuracy were found to be within -7.2 and 5.3% in terms of relative error (%). Absolute recovery of the method for lacosamide was determined at three concentration levels and ranged from 92.5 to 97.6%. The developed method uses small volumes of plasma and proved to be simple, rapid, and sensitive for the determination of lacosamide in plasma. This method can be used in routine every day analysis of plasma samples obtained from patients who follow respective antiepileptic treatment and for the investigation of clinical and forensic cases where lacosamide is involved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of an LC-MS/MS Method for Urinary Lactulose and Mannitol Quantification: Results in Patients with Irritable Bowel Syndrome.

PubMed

Gervasoni, Jacopo; Schiattarella, Arcangelo; Giorgio, Valentina; Primiano, Aniello; Russo, Consuelo; Tesori, Valentina; Scaldaferri, Franco; Urbani, Andrea; Zuppi, Cecilia; Persichilli, Silvia

2016-01-01

Aim . Lactulose/mannitol ratio is used to assess intestinal barrier function. Aim of this work was to develop a robust and rapid method for the analysis of lactulose and mannitol in urine by liquid chromatography coupled to tandem mass spectrometry. Lactulose/mannitol ratio has been measured in pediatric patients suffering from irritable bowel syndrome. Methods . Calibration curves and raffinose, used as internal standard, were prepared in water : acetonitrile 20 : 80. Fifty μ L of urine sample was added to 450  μ L of internal standard solution. The chromatographic separation was performed using a Luna NH 2 column operating at a flow rate of 200  μ L/min and eluted with a linear gradient from 20% to 80% water in acetonitrile. Total run time is 9 minutes. The mass spectrometry operates in electrospray negative mode. Method was fully validated according to European Medicine Agency guidelines. Results and Conclusions . Linearity ranged from 10 to 1000 mg/L for mannitol and 2.5 to 1000 mg/L for lactulose. Imprecision in intra- and interassay was lower than 15% for both analytes. Accuracy was higher than 85%. Lactulose/mannitol ratio in pediatric patients is significantly higher than that measured in controls. The presented method, rapid and sensitive, is suitable in a clinical laboratory.

Simultaneous determination of water-soluble vitamins in SRM 1849 Infant/Adult Nutritional Formula powder by liquid chromatography-isotope dilution mass spectrometry.

PubMed

Goldschmidt, Robert J; Wolf, Wayne R

2010-05-01

Assessing dietary intake of vitamins from all sources, including foods, dietary supplements, and fortified foods, would be aided considerably by having analytical methodologies that are capable of simultaneous determination of several vitamins. Vitamins naturally present in foods may occur in different chemical forms, with levels ranging over several orders of magnitude. Vitamins in dietary supplements and fortified foods, however, are typically added in a single chemical form, and matrix issues are usually not as complex. These sources should thus be relatively amenable to approaches that aim for simultaneous determination of multiple vitamins. Our recent work has focused on development of liquid chromatography (LC)-UV/fluorescence and LC-tandem mass spectrometry methods for the simultaneous determination of water-soluble vitamins (thiamine, niacin, pyridoxine, pantothenic acid, folic acid, biotin, and riboflavin) in dietary supplement tablets and fortified foods, such as formula powders and breakfast cereals. As part of the validation of our methods and collaboration in characterization of a new NIST SRM 1849 Infant/Adult Nutritional Formula powder, we report data on SRM 1849 using isotope dilution mass spectrometric methods. Use of available NIST Standard Reference Materials(R) as test matrices in our method development and validation gives a benchmark for future application of these methods. We compare three chromatographic approaches and provide data on stability of vitamin standard solutions for LC-based multiple vitamin determinations.

Mass Spectrometry and Ion Mobility Characterization of Bioactive Peptide-Synthetic Polymer Conjugates.

PubMed

Alalwiat, Ahlam; Tang, Wen; Gerişlioğlu, Selim; Becker, Matthew L; Wesdemiotis, Chrys

2017-01-17

The bioconjugate BMP2-(PEO-HA) 2 , composed of a dendron with two monodisperse poly(ethylene oxide) (PEO) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone growth stimulating peptide (BMP2), has been comprehensively characterized by mass spectrometry (MS) methods, encompassing matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), tandem mass spectrometry (MS 2 ), and ion mobility mass spectrometry (IM-MS). MS 2 experiments using different ion activation techniques validated the sequences of the synthetic, bioactive peptides HA and BMP2, which contained highly basic amino acid residues either at the N-terminus (BMP2) or C-terminus (HA). Application of MALDI-MS, ESI-MS, and IM-MS to the polymer-peptide biomaterial confirmed its composition. Collision cross-section measurements and molecular modeling indicated that BMP2-(PEO-HA) 2 exists in several folded and extended conformations, depending on the degree of protonation. Protonation of all basic sites of the hybrid material nearly doubles its conformational space and accessible surface area.

New evidences on efficacy of boronic acid-based derivatization method to identify sugars in plant material by gas chromatography-mass spectrometry.

PubMed

Faraco, Marianna; Fico, Daniela; Pennetta, Antonio; De Benedetto, Giuseppe E

2016-10-01

This work presents an analytical procedure based on gas chromatography-mass spectrometry which allows the determination of aldoses (glucose, mannose, galactose, arabinose, xylose, fucose, rhamnose) and chetoses (fructose) in plant material. One peak for each target carbohydrate was obtained by using an efficient derivatization employing methylboronic acid and acetic anhydride sequentially, whereas the baseline separation of the analytes was accomplished using an ionic liquid capillary column. First, the proposed method was optimized and validated. Successively, it was applied to identify the carbohydrates present in plant material. Finally, the procedure was successfully applied to samples from a XVII century painting, thus highlighting the occurrence of starch glue and fruit tree gum as polysaccharide materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of Phosphonic Acids: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Vu, A; Koester, C

The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method titled Analysis of Diisopropyl Methylphosphonate, Ethyl Hydrogen Dimethylamidophosphate, Isopropyl Methylphosphonic Acid, Methylphosphonic Acid, and Pinacolyl Methylphosphonic Acid in Water by Multiple Reaction Monitoring Liquid Chromatography/Tandem Mass Spectrometry: EPA Version MS999. This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to validate and verify the analytical procedures describedmore » in EPA Method MS999 for analysis of the listed phosphonic acids and surrogates in aqueous samples. The gathered data from this validation study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of EPA Method MS999 can be determined.« less

Detection of anabolic and androgenic steroids and/or their esters in horse hair using ultra-high performance liquid chromatography-high resolution mass spectrometry.

PubMed

Kwok, Karen Y; Choi, Timmy L S; Kwok, Wai Him; Wong, Jenny K Y; Wan, Terence S M

2017-04-14

Anabolic and androgenic steroids (AASs) are a class of prohibited substances banned in horseracing at all times. The common approach for controlling the misuse of AASs in equine sports is by detecting the presence of AASs and/or their metabolites in urine and blood samples using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). This approach, however, often falls short as the duration of effect for many AASs are longer than their detection time in both urine and blood. As a result, there is a high risk that such AASs could escape detection in their official race-day samples although they may have been used during the long period of training. Hair analysis, on the other hand, can afford significantly longer detection windows. In addition, the identification of synthetic ester derivatives of AASs in hair, particularly for the endogenous ones, can provide unequivocal proof of their exogenous origin. This paper describes the development of a sensitive method (at sub to low parts-per-billion or ppb levels) for detecting 48 AASs and/or their esters in horse hair using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Decontaminated horse hair was pulverised and subjected to in-situ liquid-liquid extraction in a mixture of hexane - ethyl acetate (7:3, v/v) and phosphate buffer (0.1M, pH 9.5), followed by additional clean-up using mixed-mode solid-phase extraction. The final extract was analysed using UHPLC-HRMS in the positive electrospray ionisation (ESI) mode with both full scan and parallel reaction monitoring (PRM). This method was validated for qualitative identification purposes. Validation data, including method specificity, method sensitivity, extraction recovery, method precision and matrix effect are presented. Method applicability was demonstrated by the successful detection and confirmation of testosterone propionate in a referee hair sample. To our knowledge, this was the first report of a comprehensive screening method for detecting as many as 48 AASs and/or their esters in horse hair. Moreover, retrospective analysis of non-targeted AASs and/or their esters was made feasible by re-examining the full scan UHPLC-HRMS data acquired. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of mycotoxins in different food commodities by ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry.

PubMed

Beltrán, Eduardo; Ibáñez, María; Sancho, Juan Vicente; Hernández, Félix

2009-06-01

A rapid multianalyte-multiclass method with little sample manipulation has been developed for the simultaneous determination of eleven mycotoxins in different food commodities by using ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC/MS/MS). Toxins were extracted from the samples with acetonitrile/water (80:20, v/v) 0.1% HCOOH and, after a two-fold dilution with water, directly injected into the system. Thanks to the fast high-resolution separation of UHPLC, the eleven mycotoxins were separated by gradient elution in only 4 min. The method has been validated in three food matrices (maize kernels, dry pasta (wheat), and eight-multicereal babyfood (wheat, maize, rice, oat, barley, rye, sorghum, millet)) at four different concentration levels. Satisfactory recoveries were obtained (70-110%) and precision (expressed as relative standard deviation) was typically below 15% with very few exceptions. Quantification of samples was carried out with matrix-matched standards calibration. The lowest concentration successfully validated in sample was as low as 0.5 microg/kg for aflatoxins and ochratoxin A in babyfood, and 20 microg/kg for the rest of the selected mycotoxins in all matrices tested. Deoxynivalenol could be only validated at 200 microg/kg, due the poor sensitivity for this mycotoxin analysis. With only two exceptions (HT-2 and deoxynivalenol), the limits of detection (LODs), estimated for a signal-to-noise ratio of 3 from the chromatograms of samples spiked at the lowest level validated, varied between 0.1 and 1 microg/kg in the three food matrices tested. The method was applied to the analysis of different kinds of samples. Positive findings were confirmed by acquiring two transitions (Q quantification, q confirmation) and evaluating the Q/q ratio. Copyright (c) 2009 John Wiley & Sons, Ltd.

Development and validation of a hydrophilic interaction liquid chromatography-tandem mass spectrometry method for the quantification of lipid-related extracellular metabolites in Saccharomyces cerevisiae.

PubMed

Sun, Tao; Wetzel, Stephanie J; Johnson, Mitchell E; Surlow, Beth A; Patton-Vogt, Jana

2012-05-15

A highly sensitive hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method was developed and validated for the quantification of glycerophosphoinositol (GroPIns), glycerophosphocholine (GroPCho), glycerol 3-phosphate (GroP), inositol, and choline in the extracellular medium of Saccharomyces cerevisiae. The media samples were pretreated with a single two-phase liquid extraction. Chromatographic separation was achieved on a Waters Xbridge HILIC (150 mm × 4.6 mm, 5 μm) column under isocratic conditions using a mobile phase composed of acetonitrile/water, 70:30 (v/v) with 10mM ammonium acetate (pH adjusted to 4.5) at a flow-rate of 0.5 mL/min. Using a triple quadrupole tandem mass spectrometer, samples were detected in multiple reaction monitoring (MRM) mode via an electrospray ionization (ESI) source. The calibration curves were linear (r² ≥ 0.995) over the range of 0.5-150 nM, with the lower limit of quantitation validated at 0.5 nM for all analytes. The intra- and inter-day precision (calculated by coefficient of variation, CV%) ranged from 1.24 to 5.88% and 2.46 to 9.77%, respectively, and intra- and inter-day accuracy (calculated by relative error, RE%) was between -8.42 to 8.22% and -9.35 to 6.62%, respectively, at all quality control levels. The extracellular metabolites were stable throughout various storage stability studies. The fully validated method was successfully applied to determine the extracellular levels of phospholipid-related metabolites in S. cerevisiae. Copyright © 2012 Elsevier B.V. All rights reserved.

Development and Validation of a Rapid (13)C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices.

PubMed

Matsunami, Risë K; Angelides, Kimon; Engler, David A

2015-05-18

There is currently considerable discussion about the accuracy of blood glucose concentrations determined by personal blood glucose monitoring systems (BGMS). To date, the FDA has allowed new BGMS to demonstrate accuracy in reference to other glucose measurement systems that use the same or similar enzymatic-based methods to determine glucose concentration. These types of reference measurement procedures are only comparative in nature and are subject to the same potential sources of error in measurement and system perturbations as the device under evaluation. It would be ideal to have a completely orthogonal primary method that could serve as a true standard reference measurement procedure for establishing the accuracy of new BGMS. An isotope-dilution liquid chromatography/mass spectrometry (ID-UPLC-MRM) assay was developed using (13)C6-glucose as a stable isotope analogue to specifically measure glucose concentration in human plasma, and validated for use against NIST standard reference materials, and against fresh isolates of whole blood and plasma into which exogenous glucose had been spiked. Assay performance was quantified to NIST-traceable dry weight measures for both glucose and (13)C6-glucose. The newly developed assay method was shown to be rapid, highly specific, sensitive, accurate, and precise for measuring plasma glucose levels. The assay displayed sufficient dynamic range and linearity to measure across the range of both normal and diabetic blood glucose levels. Assay performance was measured to within the same uncertainty levels (<1%) as the NIST definitive method for glucose measurement in human serum. The newly developed ID UPLC-MRM assay can serve as a validated reference measurement procedure to which new BGMS can be assessed for glucose measurement performance. © 2015 Diabetes Technology Society.

Application of a novel liquid chromatography/tandem mass spectrometry method for the determination of antazoline in human plasma: Result of ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study.

PubMed

Giebułtowicz, Joanna; Piotrowski, Roman; Baran, Jakub; Kułakowski, Piotr; Wroczyński, Piotr

2016-05-10

Antazoline is a first-generation antihistaminic agent with antiarrhythmic quinidine-like properties. In some countries, it is widely used for termination of cardiac arrhythmias, especially atrial fibrillation (AF). However, no human pharmacokinetic studies have been conducted with intravenous antazoline. The aim of our study was to develop and validate a novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the determination of antazoline in human plasma: the ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study. Antazoline was extracted from plasma using liquid-liquid extraction. The concentration of the analyte was measured by LC-MS/MS with xylometazoline as an internal standard. The method was validated for linearity, precision, accuracy, stability (freeze/thaw stability, stability in autosampler, short and long term stability), dilution integrity and matrix effect. The analyzed validation criteria were fulfilled. The method was applied to a pharmacokinetic study involving 10 healthy volunteers. Following a single intravenous dose of antazoline mesylate (100 mg), the plasma concentration profile showed a relative fast elimination with a terminal elimination half-life of 2.29 h. A relatively high volume of distribution was observed (Vss=315 L). The values of mean residence time (MRT∞), area under the curve (AUC∞) and clearance were 3.45 h, 0.91 mg h L(-1) and 80.5 L h(-1), respectively. One volunteer showed significant differences in pharmacokinetic parameters. In conclusion, the proposed new LC-MS/MS method was successfully used for the first time for the determination of antazoline in human plasma. Copyright © 2016 Elsevier B.V. All rights reserved.

Segmental analysis of amphetamines in hair using a sensitive UHPLC-MS/MS method.

PubMed

Jakobsson, Gerd; Kronstrand, Robert

2014-06-01

A sensitive and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy methamphetamine in hair samples. Segmented hair (10 mg) was incubated in 2M sodium hydroxide (80°C, 10 min) before liquid-liquid extraction with isooctane followed by centrifugation and evaporation of the organic phase to dryness. The residue was reconstituted in methanol:formate buffer pH 3 (20:80). The total run time was 4 min and after optimization of UHPLC-MS/MS-parameters validation included selectivity, matrix effects, recovery, process efficiency, calibration model and range, lower limit of quantification, precision and bias. The calibration curve ranged from 0.02 to 12.5 ng/mg, and the recovery was between 62 and 83%. During validation the bias was less than ±7% and the imprecision was less than 5% for all analytes. In routine analysis, fortified control samples demonstrated an imprecision <13% and control samples made from authentic hair demonstrated an imprecision <26%. The method was applied to samples from a controlled study of amphetamine intake as well as forensic hair samples previously analyzed with an ultra high performance liquid chromatography time of flight mass spectrometry (UHPLC-TOF-MS) screening method. The proposed method was suitable for quantification of these drugs in forensic cases including violent crimes, autopsy cases, drug testing and re-granting of driving licences. This study also demonstrated that if hair samples are divided into several short segments, the time point for intake of a small dose of amphetamine can be estimated, which might be useful when drug facilitated crimes are investigated. Copyright © 2014 John Wiley & Sons, Ltd.

Direct total and free testosterone measurement by liquid chromatography tandem mass spectrometry across two different platforms.

PubMed

Rhea, Jeanne M; French, Deborah; Molinaro, Ross J

2013-05-01

To develop and validate liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for the direct measurement of total and free testosterone in patient samples on two different analytical systems. An API 4000 and 5000 triple quadropoles were used and compared; the former is reported to be 3-5 times less sensitive, as was used to set the quantitation limits. Free testosterone was separated from the protein-bound fraction by equilibrium dialysis followed by derivatization. Either free or total testosterone, and a deuterated internal standard (d3-testosterone) were extracted by liquid-liquid extraction. The validation results were compared to two different clinical laboratories. The use of d2-testosterone was found to be unacceptable for our method. The total testosterone LC-MS/MS methods on both systems were linear over a wide concentration range of 1.5-2000ng/dL. Free testosterone was measured directly using equilibrium dialysis coupled LC-MS/MS and linear over the concentration range of 2.5-2500pg/mL. Good correlation (total testosterone, R(2)=0.96; free testosterone, R(2)=0.98) was observed between our LC-MS/MS systems and comparator laboratory. However, differences in absolute values for both free and total testosterone measurements were observed while a comparison to a second published LC-MS/MS method showed excellent correlation. Free and total testosterone measurements correlated well with clinical observations. To our knowledge, this is the first published validation of free and total testosterone methods across two analytical systems of different analytical sensitivities. A less sensitive system does not sacrifice analytical or clinical sensitivity to directly measure free and total testosterone in patient samples. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Multi-residue method for the determination of pesticides and pesticide metabolites in honeybees by liquid and gas chromatography coupled with tandem mass spectrometry--Honeybee poisoning incidents.

PubMed

Kiljanek, Tomasz; Niewiadowska, Alicja; Semeniuk, Stanisław; Gaweł, Marta; Borzęcka, Milena; Posyniak, Andrzej

2016-02-26

A method for the determination of 200 pesticides and pesticide metabolites in honeybee samples has been developed and validated. Almost 98% of compounds included in this method are approved to use within European Union, as active substances of plant protection products or veterinary medicinal products used by beekeepers to control mites Varroa destructor in hives. Many significant metabolites, like metabolites of imidacloprid, thiacloprid, fipronil, methiocarb and amitraz, are also possible to detect. The sample preparation was based on the buffered QuEChERS method. Samples of bees were extracted with acetonitrile containing 1% acetic acid and then subjected to clean-up by dispersive solid phase extraction (dSPE) using a new Z-Sep+ sorbent and PSA. The majority of pesticides, including neonicotionoids and their metabolites, were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) but some of pesticides, especially pyrethroid insecticides, were analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS). The procedure was validated according to the Guidance document SANCO/12571/2013 at four concentration levels: 1, 5, 10 and 100 ng/g bees and verified in the international proficiency test. The analysis of bee samples spiked at the limit of quantification (LOQ) showed about 98% mean recovery value (trueness) and 97% of analytes showed recovery in the required range of 70-120% and RSDr (precision) below 20%. Linearity and matrix effects were also established. The LOQs of pesticides were in the range of 1-100 ng/g. The developed method allows determination of insecticides at concentrations of 10 ng/g or less, except abamectin and tebufenozide. LOQ values are lower than the median lethal doses LD50 for bees. The method was used to investigate more than 70 honeybee poisoning incidents. Data about detected pesticides and their metabolites are included. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic-tandem mass spectrometric method.

PubMed

Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A

2012-11-01

A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25-6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. Copyright © 2012 Elsevier B.V. All rights reserved.

Specter: linear deconvolution for targeted analysis of data-independent acquisition mass spectrometry proteomics.

PubMed

Peckner, Ryan; Myers, Samuel A; Jacome, Alvaro Sebastian Vaca; Egertson, Jarrett D; Abelin, Jennifer G; MacCoss, Michael J; Carr, Steven A; Jaffe, Jacob D

2018-05-01

Mass spectrometry with data-independent acquisition (DIA) is a promising method to improve the comprehensiveness and reproducibility of targeted and discovery proteomics, in theory by systematically measuring all peptide precursors in a biological sample. However, the analytical challenges involved in discriminating between peptides with similar sequences in convoluted spectra have limited its applicability in important cases, such as the detection of single-nucleotide polymorphisms (SNPs) and alternative site localizations in phosphoproteomics data. We report Specter (https://github.com/rpeckner-broad/Specter), an open-source software tool that uses linear algebra to deconvolute DIA mixture spectra directly through comparison to a spectral library, thus circumventing the problems associated with typical fragment-correlation-based approaches. We validate the sensitivity of Specter and its performance relative to that of other methods, and show that Specter is able to successfully analyze cases involving highly similar peptides that are typically challenging for DIA analysis methods.

Isolation of 236U and 239,240Pu from seawater samples and its determination by Accelerator Mass Spectrometry.

PubMed

López-Lora, Mercedes; Chamizo, Elena; Villa-Alfageme, María; Hurtado-Bermúdez, Santiago; Casacuberta, Núria; García-León, Manuel

2018-02-01

In this work we present and evaluate a radiochemical procedure optimised for the analysis of 236 U and 239,240 Pu in seawater samples by Accelerator Mass Spectrometry (AMS). The method is based on Fe(OH) 3 co-precipitation of actinides and uses TEVA® and UTEVA® extraction chromatography resins in a simplified way for the final U and Pu purification. In order to improve the performance of the method, the radiochemical yields are analysed in 1 to 10L seawater volumes using alpha spectrometry (AS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Robust 80% plutonium recoveries are obtained; however, it is found that Fe(III) concentration in the precipitation solution and sample volume are the two critical and correlated parameters influencing the initial uranium extraction through Fe(OH) 3 co-precipitation. Therefore, we propose an expression that optimises the sample volume and Fe(III) amounts according to both the 236 U and 239,240 Pu concentrations in the samples and the performance parameters of the AMS facility. The method is validated for the current setup of the 1MV AMS system (CNA, Sevilla, Spain), where He gas is used as a stripper, by analysing a set of intercomparison seawater samples, together with the Laboratory of Ion Beam Physics (ETH, Zürich, Switzerland). Copyright © 2017 Elsevier B.V. All rights reserved.

Quantification of 11-Nor-9-Carboxy-Δ9-Tetrahydrocannabinol in Human Oral Fluid by Gas Chromatography–Tandem Mass Spectrometry

PubMed Central

Barnes, Allan J.; Scheidweiler, Karl B.; Huestis, Marilyn A.

2015-01-01

A sensitive and specific method for the quantification of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) in oral fluid collected with the Quantisal and Oral-Eze devices was developed and fully validated. Extracted analytes were derivatized with hexafluoroisopropanol and trifluoroacetic anhydride and quantified by gas chromatography–tandem mass spectrometry with negative chemical ionization. Standard curves, using linear least-squares regression with 1/x2 weighting were linear from 10 to 1000 ng/L with coefficients of determination >0.998 for both collection devices. Bias was 89.2%–112.6%, total imprecision 4.0%–5.1% coefficient of variation, and extraction efficiency >79.8% across the linear range for Quantisal-collected specimens. Bias was 84.6%–109.3%, total imprecision 3.6%–7.3% coefficient of variation, and extraction efficiency >92.6% for specimens collected with the Oral-Eze device at all 3 quality control concentrations (10, 120, and 750 ng/L). This effective high-throughput method reduces analysis time by 9 minutes per sample compared with our current 2-dimensional gas chromatography–mass spectrometry method and extends the capability of quantifying this important oral fluid analyte to gas chromatography–tandem mass spectrometry. This method was applied to the analysis of oral fluid specimens collected from individuals participating in controlled cannabis studies and will be effective for distinguishing passive environmental contamination from active cannabis smoking. PMID:24622724

Accurate determination of selected pesticides in soya beans by liquid chromatography coupled to isotope dilution mass spectrometry.

PubMed

Huertas Pérez, J F; Sejerøe-Olsen, B; Fernández Alba, A R; Schimmel, H; Dabrio, M

2015-05-01

A sensitive, accurate and simple liquid chromatography coupled with mass spectrometry method for the determination of 10 selected pesticides in soya beans has been developed and validated. The method is intended for use during the characterization of selected pesticides in a reference material. In this process, high accuracy and appropriate uncertainty levels associated to the analytical measurements are of utmost importance. The analytical procedure is based on sample extraction by the use of a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction and subsequent clean-up of the extract with C18, PSA and Florisil. Analytes were separated on a C18 column using gradient elution with water-methanol/2.5 mM ammonium acetate mobile phase, and finally identified and quantified by triple quadrupole mass spectrometry in the multiple reaction monitoring mode (MRM). Reliable and accurate quantification of the analytes was achieved by means of stable isotope-labelled analogues employed as internal standards (IS) and calibration with pure substance solutions containing both, the isotopically labelled and native compounds. Exceptions were made for thiodicarb and malaoxon where the isotopically labelled congeners were not commercially available at the time of analysis. For the quantification of those compounds methomyl-(13)C2(15)N and malathion-D10 were used respectively. The method was validated according to the general principles covered by DG SANCO guidelines. However, validation criteria were set more stringently. Mean recoveries were in the range of 86-103% with RSDs lower than 8.1%. Repeatability and intermediate precision were in the range of 3.9-7.6% and 1.9-8.7% respectively. LODs were theoretically estimated and experimentally confirmed to be in the range 0.001-0.005 mg kg(-1) in the matrix, while LOQs established as the lowest spiking mass fractionation level were in the range 0.01-0.05 mg kg(-1). The method reliably identifies and quantifies the selected pesticides in soya beans at appropriate uncertainty levels, making it suitable for the characterization of candidate reference materials. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Determination of methylmercury in marine biota samples with advanced mercury analyzer: method validation.

PubMed

Azemard, Sabine; Vassileva, Emilia

2015-06-01

In this paper, we present a simple, fast and cost-effective method for determination of methyl mercury (MeHg) in marine samples. All important parameters influencing the sample preparation process were investigated and optimized. Full validation of the method was performed in accordance to the ISO-17025 (ISO/IEC, 2005) and Eurachem guidelines. Blanks, selectivity, working range (0.09-3.0ng), recovery (92-108%), intermediate precision (1.7-4.5%), traceability, limit of detection (0.009ng), limit of quantification (0.045ng) and expanded uncertainty (15%, k=2) were assessed. Estimation of the uncertainty contribution of each parameter and the demonstration of traceability of measurement results was provided as well. Furthermore, the selectivity of the method was studied by analyzing the same sample extracts by advanced mercury analyzer (AMA) and gas chromatography-atomic fluorescence spectrometry (GC-AFS). Additional validation of the proposed procedure was effectuated by participation in the IAEA-461 worldwide inter-laboratory comparison exercises. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry.

PubMed

Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro

2017-09-01

Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg -1 ; ICP-MS, 437ngg -1 ) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses. Copyright © 2016 Elsevier GmbH. All rights reserved.

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

2014-12-03

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.

Application of supercritical fluid chromatography coupled to mass spectrometry to the determination of fat-soluble vitamins in selected food products.

PubMed

Oberson, Jean-Marie; Campos-Giménez, Esther; Rivière, Johann; Martin, Frédéric

2018-06-01

In the present manuscript, we describe a fully optimized and validated method suitable to analyse nine compounds (retinyl acetate, retinyl palmitate, retinol, α-tocopherol, α-tocopheryl acetate, cholecalciferol, ergocalciferol, phylloquinone, menaquinone-4) representing the major contributors to the fat-soluble vitamin activity of selected food products (infant formulas, adult nutritionals, infant cereals and mixed meals). Sample preparation involves direct solvent extraction using enzyme-assisted matrix disintegration and methanolic protein precipitation. Direct injection of the extract allows quantification of vitamins A, E and K in only 7 min, while vitamin D is determined after fast derivatization of the extract. Separation is achieved by supercritical fluid chromatography and detection performed by tandem mass spectrometry in positive Atmospheric Pressure Chemical Ionization mode. Results on a Standard Reference Material (SRM 1849a Infant/Adult Nutritional) were not statistically different from reference values. Full validation of the method showed excellent overall performance. Average recovery rate was between 90 and 110% for all vitamins and matrixes. The methodology shows enhanced safety and reduced cost as compared with previously published methods, together with potential for application to more complex matrixes. The full procedure can be easily applied in control laboratories dramatically increasing sample throughput and reducing solvent consumption. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of L-ephedrine, pseudoephedrine, and caffeine in rat plasma by liquid chromatography-tandem mass spectrometry.

PubMed

Cooper, Stephen D; Fletcher, Brenda L; Silinski, Melanie A Rehder; Brown, Sherri S; Lodge, Jon W; Fernando, Reshan A; Collins, Bradley J

2011-07-01

A rapid and simple liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of L-ephedrine, pseudoephedrine, and caffeine in male Fisher-344 rat plasma at nanogram-per-milliliter concentrations for use in support of toxicology studies. Only 25 μL of plasma is required, and extraction is performed using a simple, single-step protein precipitation. The method was validated over a range of 2.09 to 5460 ng/mL for L-ephedrine, 2.09 to 5050 ng/mL for pseudoephedrine and 2.03 to 5340 ng/mL for caffeine. A binary gradient elution at 0.3 mL/min was used with a Waters XBridge Phenyl (2.1 × 150 mm, 3.5 μm) column and a Waters XBridge Phenyl 2.1- × 10-mm guard column at ambient temperature. The mobile phase consisted of 10 mM ammonium acetate in water (pH 5.0) and methanol. Caffeine trimethyl-(13)C(3) was used as the internal standard. The method was evaluated for linearity, recovery, precision, accuracy, and stability, and it was successfully applied in toxicokinetic studies of ephedrine, administered alone, in combination with caffeine, and in the herbal source Ma Huang.

Determination of limonin in dog plasma by liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

PubMed

Liu, Shi-jia; Zhou, Ling; Zhang, Jun; Yu, Bo-yang; Li, Chang-yin; Liu, Zi-xiu; Ju, Wen-zheng

2013-04-01

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 mm ammonium acetate buffer-methanol (26:74, v/v) on a C18 column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 469.4 → 229.3 and m/z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625-100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs. Copyright © 2012 John Wiley & Sons, Ltd.

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

A novel high-throughput method for supported liquid extraction of retinol and alpha-tocopherol from human serum and simultaneous quantitation by liquid chromatography tandem mass spectrometry.

PubMed

Hinchliffe, Edward; Rudge, James; Reed, Paul

2016-07-01

Measurement of vitamin A (retinol) and E (alpha-tocopherol) in UK clinical laboratories is currently performed exclusively by high-performance liquid chromatography with ultraviolet detection. We investigated whether retinol and alpha-tocopherol could be measured simultaneously by liquid chromatography tandem mass spectrometry. Serum samples (100 μL) were extracted using Isolute + Supported Liquid Extraction plates. Chromatography was performed on a Phenomenex Kinetex Biphenyl 2.6 μm, 50 × 2.1 mm column, and liquid chromatography tandem mass spectrometry on a Waters Acquity TQD. Injection-to-injection time was 4.3 min. The assay was validated according to published guidelines. Patient samples were used to compare liquid chromatography tandem mass spectrometry and high-performance liquid chromatography with ultraviolet detection methods. For retinol and alpha-tocopherol, respectively, the assay was linear up to 6.0 and 80.0 μmol/L, and lower limit of quantification was 0.07 and 0.26 μmol/L. Intra and interassay imprecision were within desirable analytical specifications. Analysis of quality control material aligned to NIST SRM 968e, and relative spiked recovery from human serum, both yielded results within 15% of target values. Method comparison with high-performance liquid chromatography with ultraviolet detection methodology demonstrated a negative bias for retinol and alpha-tocopherol by the liquid chromatography tandem mass spectrometry method. Analysis of United Kingdom National External Quality Assurance Scheme samples yielded mean bias from the target value of +3.0% for retinol and -11.2% for alpha-tocopherol. We have developed a novel, high-throughput method for extraction of retinol and alpha-tocopherol from human serum followed by simultaneous quantitation by liquid chromatography tandem mass spectrometry. The method offers a rapid, sensitive, specific and cost-effective alternative to high-performance liquid chromatography with ultraviolet detection methodology, and is suitable for routine clinical monitoring of patients predisposed to fat-soluble vitamin malabsorption. © The Author(s) 2015.

A need for determination of arsenic species at low levels in cereal-based food and infant cereals. Validation of a method by IC-ICPMS.

PubMed

Llorente-Mirandes, Toni; Calderón, Josep; Centrich, Francesc; Rubio, Roser; López-Sánchez, José Fermín

2014-03-15

The present study arose from the need to determine inorganic arsenic (iAs) at low levels in cereal-based food. Validated methods with a low limit of detection (LOD) are required to analyse these kinds of food. An analytical method for the determination of iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA) in cereal-based food and infant cereals is reported. The method was optimised and validated to achieve low LODs. Ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS) was used for arsenic speciation. The main quality parameters were established. To expand the applicability of the method, different cereal products were analysed: bread, biscuits, breakfast cereals, wheat flour, corn snacks, pasta and infant cereals. The total and inorganic arsenic content of 29 cereal-based food samples ranged between 3.7-35.6 and 3.1-26.0 μg As kg(-1), respectively. The present method could be considered a valuable tool for assessing inorganic arsenic contents in cereal-based foods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Validation of QuEChERS method for the determination of some pesticide residues in two apple varieties.

PubMed

Tiryaki, Osman

2016-10-02

This study was undertaken to validate the "quick, easy, cheap, effective, rugged and safe" (QuEChERS) method using Golden Delicious and Starking Delicious apple matrices spiked at 0.1 maximum residue limit (MRL), 1.0 MRL and 10 MRL levels of the four pesticides (chlorpyrifos, dimethoate, indoxacarb and imidacloprid). For the extraction and cleanup, original QuEChERS method was followed, then the samples were subjected to liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) for chromatographic analyses. According to t test, matrix effect was not significant for chlorpyrifos in both sample matrices, but it was significant for dimethoate, indoxacarb and imidacloprid in both sample matrices. Thus, matrix-matched calibration (MC) was used to compensate matrix effect and quantifications were carried out by using MC. The overall recovery of the method was 90.15% with a relative standard deviation of 13.27% (n = 330). Estimated method detection limit of analytes blew the MRLs. Some other parameters of the method validation, such as recovery, precision, accuracy and linearity were found to be within the required ranges.

Evaluation of the Effects of Ketoconazole and Voriconazole on the Pharmacokinetics of Oxcarbazepine and Its Main Metabolite MHD in Rats by UPLC-MS-MS.

PubMed

Chen, Xinxin; Gu, Ermin; Wang, Shuanghu; Zheng, Xiang; Chen, Mengchun; Wang, Li; Hu, Guoxin; Cai, Jian-ping; Zhou, Hongyu

2016-03-01

Oxcarbazepine (OXC), a second-generation antiepileptic drug, undergoes rapid reduction with formation of the active metabolite 10,11-dihydro-10-hydroxy-carbazepine (MHD) in vivo. In this study, a method for simultaneous determination of OXC and MHD in rat plasma using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS-MS) was developed and validated. Under given chromatographic conditions, OXC, MHD and internal standard diazepam were separated well and quantified by electrospray positive ionization mass spectrometry in the multiple reaction monitoring transitions mode. The method validation demonstrated good linearity over the range of 10-2,000 ng/mL for OXC and 5-1,000 ng/mL for MHD. The lower limit of quantification was 5 ng/mL for OXC and 2.5 ng/mL for MHD, respectively. The method was successfully applied to the evaluation of the pharmacokinetics of OXC and MHD in rats, with or without pretreatment by ketoconazole (KET) and voriconazole (VOR). Statistics indicated that KET and VOR significantly affected the disposition of OXC and MHD in vivo, whereas VOR predominantly interfered with the disposition of MHD. This method is suitable for pharmacokinetic study in small animals. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Quality evaluation of Semen Cassiae (Cassia obtusifolia L.) by using ultra-high performance liquid chromatography coupled with mass spectrometry.

PubMed

Zhang, Wei-Dong; Wang, Ying; Wang, Qing; Yang, Wan-Jun; Gu, Yi; Wang, Rong; Song, Xiao-Mei; Wang, Xiao-Juan

2012-08-01

A sensitive and reliable ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry has been developed and partially validated to evaluate the quality of Semen Cassiae (Cassia obtusifolia L.) through simultaneous determination of 11 anthraquinones and two naphtha-γ-pyrone compounds. The analysis was achieved on a Poroshell 120 EC-C(18) column (100 mm × 2.1 mm, 2.7 μm; Agilent, Palo Alto, CA, USA) with gradient elution using a mobile phase that consisted of acetonitrile-water (30 mM ammonium acetate) at a flow rate of 0.4 mL/min. For quantitative analysis, all calibration curves showed perfect linear regression (r(2) > 0.99) within the testing range. This method was also validated with respect to precision and accuracy, and was successfully applied to quantify the 13 components in nine batches of Semen Cassiae samples from different areas. The performance of developed method was compared with that of conventional high-performance liquid chromatography method. The significant advantages of the former include high-speed chromatographic separation, four times faster than high-performance liquid chromatography with conventional columns, and great enhancement in sensitivity. This developed method provided a new basis for overall assessment on quality of Semen Cassiae. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of praziquantel, pyrantel embonate, febantel and its active metabolites, oxfendazole and fenbendazole, in dog plasma by liquid chromatography/mass spectrometry.

PubMed

Klausz, Gabriella; Keller, Éva; Sára, Zoltán; Székely-Körmöczy, Péter; Laczay, Péter; Ary, Kornélia; Sótonyi, Péter; Róna, Kálmán

2015-12-01

A liquid chromatography-electrospray-mass spectrometry method (LC/MS) has been developed and validated for determination of praziquantel (PZQ), pyrantel (PYR), febantel (FBT), and the active metabolites fenbendazole (FEN) and oxfendazole (OXF), in dog plasma, using mebendazole as internal standard (IS). The method consists of solid-phase extractions on Strata-X polymeric cartridges. Chromatographic separation was carried out on a Phenomenex Gemini C6 -Phenyl column using binary gradient elution containing methanol and 50 mm ammonium-formate (pH 3). The method was linear (r(2)  ≥ 0.990) over concentration ranges of 3-250 ng/mL for PYR andFEB, 5-250 ng/mL for OXF and FEN, and 24-1000 ng/mL for PZQ. The mean precisions were 1.3-10.6% (within-run) and 2.5-9.1% (between-run), and mean accuracies were 90.7-109.4% (within-run) and 91.6-108.2% (between-run). The relative standard deviations (RSD) were <9.1%. The mean recoveries of five targeted compounds from dog plasma ranged from 77 to 94%.The new LC/MS method described herein was fully validated and successfully applied to the bioequivalence studies of different anthelmintic formulations such as tablets containing PZQ, PYR embonate and FBT in dogs after oral administration. Copyright © 2015 John Wiley & Sons, Ltd.

Simultaneous determination of mushroom toxins α-amanitin, β-amanitin and muscarine in human urine by solid-phase extraction and ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry.

PubMed

Tomková, Jana; Ondra, Peter; Válka, Ivo

2015-06-01

This paper presents a method for the simultaneous determination of α-amanitin, β-amanitin and muscarine in human urine by solid-phase extraction (SPE) and ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry. The method can be used for a diagnostics of mushroom poisonings. Different SPE cartridges were tested for sample preparation, namely hydrophilic modified reversed-phase (Oasis HLB) and polymeric weak cation phase (Strata X-CW). The latter gave better results and therefore it was chosen for the subsequent method optimization and partial validation. In the course of validation, limits of detection, linearity, intraday and interday precisions and recoveries were evaluated. The obtained LOD values of α-amanitin and β-amanitin were 1ng/mL and of muscarine 0.09ng/mL. The intraday and interday precisions of human urine spiked with α-amanitin (10ng/mL), β-amanitin (10ng/mL) and muscarine (1ng/mL) ranged from 6% to 10% and from 7% to 13%, respectively. The developed method was proved to be a relevant tool for the simultaneous determination of the studied mushroom toxins in human urine after mushroom poisoning. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Determination of lipophilic marine toxins in mussels. Quantification and confirmation criteria using high resolution mass spectrometry.

PubMed

Domènech, Albert; Cortés-Francisco, Nuria; Palacios, Oscar; Franco, José M; Riobó, Pilar; Llerena, José J; Vichi, Stefania; Caixach, Josep

2014-02-07

A multitoxin method has been developed for quantification and confirmation of lipophilic marine biotoxins in mussels by liquid chromatography coupled to high resolution mass spectrometry (HRMS), using an Orbitrap-Exactive HCD mass spectrometer. Okadaic acid (OA), yessotoxin, azaspiracid-1, gymnodimine, 13-desmethyl spirolide C, pectenotoxin-2 and Brevetoxin B were analyzed as representative compounds of each lipophilic toxin group. HRMS identification and confirmation criteria were established. Fragment and isotope ions and ion ratios were studied and evaluated for confirmation purpose. In depth characterization of full scan and fragmentation spectrum of the main toxins were carried out. Accuracy (trueness and precision), linearity, calibration curve check, limit of quantification (LOQ) and specificity were the parameters established for the method validation. The validation was performed at 0.5 times the current European Union permitted levels. The method performed very well for the parameters investigated. The trueness, expressed as recovery, ranged from 80% to 94%, the precision, expressed as intralaboratory reproducibility, ranged from 5% to 22% and the LOQs range from 0.9 to 4.8pg on column. Uncertainty of the method was also estimated for OA, using a certified reference material. A top-down approach considering two main contributions: those arising from the trueness studies and those coming from the precision's determination, was used. An overall expanded uncertainty of 38% was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

MSX-3D: a tool to validate 3D protein models using mass spectrometry.

PubMed

Heymann, Michaël; Paramelle, David; Subra, Gilles; Forest, Eric; Martinez, Jean; Geourjon, Christophe; Deléage, Gilbert

2008-12-01

The technique of chemical cross-linking followed by mass spectrometry has proven to bring valuable information about the protein structure and interactions between proteic subunits. It is an effective and efficient way to experimentally investigate some aspects of a protein structure when NMR and X-ray crystallography data are lacking. We introduce MSX-3D, a tool specifically geared to validate protein models using mass spectrometry. In addition to classical peptides identifications, it allows an interactive 3D visualization of the distance constraints derived from a cross-linking experiment. Freely available at http://proteomics-pbil.ibcp.fr

Comprehensive analysis of ß-lactam antibiotics including penicillins, cephalosporins, and carbapenems in poultry muscle using liquid chromatography coupled to tandem mass spectrometry.

PubMed

Berendsen, Bjorn J A; Gerritsen, Henk W; Wegh, Robin S; Lameris, Steven; van Sebille, Ralph; Stolker, Alida A M; Nielen, Michel W F

2013-09-01

A comprehensive method for the quantitative residue analysis of trace levels of 22 ß-lactam antibiotics, including penicillins, cephalosporins, and carbapenems, in poultry muscle by liquid chromatography in combination with tandem mass spectrometric detection is reported. The samples analyzed for ß-lactam residues are hydrolyzed using piperidine in order to improve compound stability and to include the total residue content of the cephalosporin ceftifour. The reaction procedure was optimized using a full experimental design. Following detailed isotope labeling, tandem mass spectrometry studies and exact mass measurements using high-resolution mass spectrometry reaction schemes could be proposed for all ß-lactams studied. The main reaction occurring is the hydrolysis of the ß-lactam ring under formation of the piperidine substituted amide. For some ß-lactams, multiple isobaric hydrolysis reaction products are obtained, in accordance with expectations, but this did not hamper quantitative analysis. The final method was fully validated as a quantitative confirmatory residue analysis method according to Commission Decision 2002/657/EC and showed satisfactory quantitative performance for all compounds with trueness between 80 and 110% and within-laboratory reproducibility below 22% at target level, except for biapenem. For biapenem, the method proved to be suitable for qualitative analysis only.

Molecularly imprinted solid phase extraction for simultaneous determination of Δ9-tetrahydrocannabinol and its main metabolites by gas chromatography-mass spectrometry in urine samples.

PubMed

Nestić, Marina; Babić, Sandra; Pavlović, Dragana Mutavdžić; Sutlović, Davorka

2013-09-10

In presented paper analytical method based on solid-phase extraction using molecularly imprinted polymer and gas chromatography-mass spectrometry has been developed and validated for the confirmation of THC, THC-OH and THC-COOH in urine samples. Non-covalent molecularly imprinted polymers of THC-OH were prepared using different functional monomers (methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate), ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator of radical polymerization. Analytes were extracted from urine samples using prepared polymer sorbent with highest binding selectivity and capability. Before extraction, urine samples were hydrolyzed with alkaline. Elution was performed with chloroform:ethyl acetate (60:40, v/v). Dry extracts were silylated with BSTFA+1% TMCS. Detection and quantification were performed using gas chromatography-mass spectrometry in single ion recording mode. The developed method was linear over the range from LOQ to 150 ng mL(-1) for all three analytes. For THC, THC-OH and THC-COOH LOD was 2.5, 1 and 1 ng mL(-1), and LOQ was 3, 2 and 2 ng mL(-1), respectively. The precision, accuracy, recovery and matrix effect were investigated at 5, 25 and 50 ng mL(-1). In the investigated concentration range recoveries were 71.9% for THC, 78.6% for THC-OH and 75.2% for THC-COOH. Matrix effect was not significant (<10%) for all analytes in the concentration range from 5 ng mL(-1) to 50 ng mL(-1). Extraction recovery on non-imprinted polymer was relatively high indicating high non-specific binding. Optimized and validated method was applied to 15 post-mortem urine samples. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Improving quantitative gas chromatography-electron ionization mass spectrometry results using a modified ion source: demonstration for a pharmaceutical application.

PubMed

D'Autry, Ward; Wolfs, Kris; Hoogmartens, Jos; Adams, Erwin; Van Schepdael, Ann

2011-07-01

Gas chromatography-mass spectrometry is a well established analytical technique. However, mass spectrometers with electron ionization sources may suffer from signal drifts, hereby negatively influencing quantitative performance. To demonstrate this phenomenon for a real application, a static headspace-gas chromatography method in combination with electron ionization-quadrupole mass spectrometry was optimized for the determination of residual dichloromethane in coronary stent coatings. Validating the method, the quantitative performance of an original stainless steel ion source was compared to that of a modified ion source. Ion source modification included the application of a gold coating on the repeller and exit plate. Several validation aspects such as limit of detection, limit of quantification, linearity and precision were evaluated using both ion sources. It was found that, as expected, the stainless steel ion source suffered from signal drift. As a consequence, non-linearity and high RSD values for repeated analyses were obtained. An additional experiment was performed to check whether an internal standard compound would lead to better results. It was found that the signal drift patterns of the analyte and internal standard were different, consequently leading to high RSD values for the response factor. With the modified ion source however, a more stable signal was observed resulting in acceptable linearity and precision. Moreover, it was also found that sensitivity improved compared to the stainless steel ion source. Finally, the optimized method with the modified ion source was applied to determine residual dichloromethane in the coating of coronary stents. The solvent was detected but found to be below the limit of quantification. Copyright © 2011 Elsevier B.V. All rights reserved.

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). Copyright © 2016 Elsevier Inc. All rights reserved.

Validation of Direct Analysis Real Time source/Time-of-Flight Mass Spectrometry for organophosphate quantitation on wafer surface.

PubMed

Hayeck, Nathalie; Ravier, Sylvain; Gemayel, Rachel; Gligorovski, Sasho; Poulet, Irène; Maalouly, Jacqueline; Wortham, Henri

2015-11-01

Microelectronic wafers are exposed to airborne molecular contamination (AMC) during the fabrication process of microelectronic components. The organophosphate compounds belonging to the dopant group are one of the most harmful groups. Once adsorbed on the wafer surface these compounds hardly desorb and could diffuse in the bulk of the wafer and invert the wafer from p-type to n-type. The presence of these compounds on wafer surface could have electrical effect on the microelectronic components. For these reasons, it is of importance to control the amount of these compounds on the surface of the wafer. As a result, a fast quantitative and qualitative analytical method, nondestructive for the wafers, is needed to be able to adjust the process and avoid the loss of an important quantity of processed wafers due to the contamination by organophosphate compounds. Here we developed and validated an analytical method for the determination of organic compounds adsorbed on the surface of microelectronic wafers using the Direct Analysis in Real Time-Time of Flight-Mass Spectrometry (DART-ToF-MS) system. Specifically, the developed methodology concerns the organophosphate group. Copyright © 2015 Elsevier B.V. All rights reserved.

Fast and solvent-free quantitation of boar taint odorants in pig fat by stable isotope dilution analysis-dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry.

PubMed

Fischer, Jochen; Haas, Torsten; Leppert, Jan; Lammers, Peter Schulze; Horner, Gerhard; Wüst, Matthias; Boeker, Peter

2014-09-01

Boar taint is a specific off-odour of boar meat products, known to be caused by at least three unpleasant odorants, with very low odour thresholds. Androstenone is a boar pheromone produced in the testes, whereas skatole and indole originate from the microbial breakdown of tryptophan in the intestinal tract. A new procedure, applying stable isotope dilution analysis (SIDA) and dynamic headspace-thermal desorption-gas chromatography/time-of-flight mass spectrometry (dynHS-TD-GC/TOFMS) for the simultaneous quantitation of these boar taint compounds in pig fat was elaborated and validated in this paper. The new method is characterised by a simple and solvent-free dynamic headspace sampling. The deuterated compounds d3-androstenone, d3-skatole and d6-indole were used as internal standards to eliminate matrix effects. The method validation performed revealed low limits of detection (LOD) and quantitation (LOQ) with high accuracy and precision, thus confirming the feasibility of the new dynHS-TD-GC/TOFMS approach for routine analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Development of liquid chromatography-tandem mass spectrometry methods for the quantitation of Anisakis simplex proteins in fish.

PubMed

Fæste, Christiane Kruse; Moen, Anders; Schniedewind, Björn; Haug Anonsen, Jan; Klawitter, Jelena; Christians, Uwe

2016-02-05

The parasite Anisakis simplex is present in many marine fish species that are directly used as food or in processed products. The anisakid larvae infect mostly the gut and inner organs of fish but have also been shown to penetrate into the fillet. Thus, human health can be at risk, either by contracting anisakiasis through the consumption of raw or under-cooked fish, or by sensitisation to anisakid proteins in processed food. A number of different methods for the detection of A. simplex in fish and products thereof have been developed, including visual techniques and PCR for larvae tracing, and immunological assays for the determination of proteins. The recent identification of a number of anisakid proteins by mass spectrometry-based proteomics has laid the groundwork for the development of two quantitative liquid chromatography-tandem mass spectrometry methods for the detection of A. simplex in fish that are described in the present study. Both, the label-free semi-quantitative nLC-nESI-Orbitrap-MS/MS (MS1) and the heavy peptide-applying absolute-quantitative (AQUA) LC-TripleQ-MS/MS (MS2) use unique reporter peptides derived from anisakid hemoglobin and SXP/RAL-2 protein as analytes. Standard curves in buffer and in salmon matrix showed limits of detection at 1μg/mL and 10μg/mL for MS1 and 0.1μg/mL and 2μg/mL for MS2. Preliminary method validation included the assessment of sensitivity, repeatability, reproducibility, and applicability to incurred and naturally-contaminated samples for both assays. By further optimization and full validation in accordance with current recommendations the LC-MS/MS methods could be standardized and used generally as confirmative techniques for the detection of A. simplex protein in fish. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance assessment of two lysis methods for direct identification of yeasts from clinical blood cultures using MALDI-TOF mass spectrometry.

PubMed

Jeddi, Fakhri; Yapo-Kouadio, Gisèle Cha; Normand, Anne-Cécile; Cassagne, Carole; Marty, Pierre; Piarroux, Renaud

2017-02-01

In cases of fungal infection of the bloodstream, rapid species identification is crucial to provide adapted therapy and thereby ameliorate patient outcome. Currently, the commercial Sepsityper kit and the sodium-dodecyl sulfate (SDS) method coupled with MALDI-TOF mass spectrometry are the most commonly reported lysis protocols for direct identification of fungi from positive blood culture vials. However, the performance of these two protocols has never been compared on clinical samples. Accordingly, we performed a two-step survey on two distinct panels of clinical positive blood culture vials to identify the most efficient protocol, establish an appropriate log score (LS) cut-off, and validate the best method. We first compared the performance of the Sepsityper and the SDS protocols on 71 clinical samples. For 69 monomicrobial samples, mass spectrometry LS values were significantly higher with the SDS protocol than with the Sepsityper method (P < .0001), especially when the best score of four deposited spots was considered. Next, we established the LS cut-off for accurate identification at 1.7, based on specimen DNA sequence data. Using this LS cut-off, 66 (95.6%) and 46 (66.6%) isolates were correctly identified at the species level with the SDS and the Sepsityper protocols, respectively. In the second arm of the survey, we validated the SDS protocol on an additional panel of 94 clinical samples. Ninety-two (98.9%) of 93 monomicrobial samples were correctly identified at the species level (median LS = 2.061). Overall, our data suggest that the SDS method yields more accurate species identification of yeasts, than the Sepsityper protocol. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Optimization and Validation of Thermal Desorption Gas Chromatography-Mass Spectrometry for the Determination of Polycyclic Aromatic Hydrocarbons in Ambient Air

PubMed Central

Durana, Nieves; García, José Antonio; Gómez, María Carmen; Alonso, Lucio

2018-01-01

Thermal desorption (TD) coupled with gas chromatography/mass spectrometry (TD-GC/MS) is a simple alternative that overcomes the main drawbacks of the solvent extraction-based method: long extraction times, high sample manipulation, and large amounts of solvent waste. This work describes the optimization of TD-GC/MS for the measurement of airborne polycyclic aromatic hydrocarbons (PAHs) in particulate phase. The performance of the method was tested by Standard Reference Material (SRM) 1649b urban dust and compared with the conventional method (Soxhlet extraction-GC/MS), showing a better recovery (mean of 97%), precision (mean of 12%), and accuracy (±25%) for the determination of 14 EPA PAHs. Furthermore, other 15 nonpriority PAHs were identified and quantified using their relative response factors (RRFs). Finally, the proposed method was successfully applied for the quantification of PAHs in real 8 h-samples (PM10), demonstrating its capability for determination of these compounds in short-term monitoring. PMID:29854561

Development and validation of a FIA/UV-vis method for pK(a) determination of oxime based acetylcholinesterase reactivators.

PubMed

Musil, Karel; Florianova, Veronika; Bucek, Pavel; Dohnal, Vlastimil; Kuca, Kamil; Musilek, Kamil

2016-01-05

Acetylcholinesterase reactivators (oximes) are compounds used for antidotal treatment in case of organophosphorus poisoning. The dissociation constants (pK(a1)) of ten standard or promising acetylcholinesterase reactivators were determined by ultraviolet absorption spectrometry. Two methods of spectra measurement (UV-vis spectrometry, FIA/UV-vis) were applied and compared. The soft and hard models for calculation of pK(a1) values were performed. The pK(a1) values were recommended in the range 7.00-8.35, where at least 10% of oximate anion is available for organophosphate reactivation. All tested oximes were found to have pK(a1) in this range. The FIA/UV-vis method provided rapid sample throughput, low sample consumption, high sensitivity and precision compared to standard UV-vis method. The hard calculation model was proposed as more accurate for pK(a1) calculation. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous Determination of Isopyrazam and Azoxystrobin in Cucumbers by Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Hu, Dan; Xu, Xu; Cai, Tian; Wang, Wei-Ying; Wu, Chun-Jie; Ye, Li-Ming

2017-12-01

A rapid and sensitive analytical method based on high-performance liquid chromatography-tandem mass spectrometry was developed and validated for the determination of isopyrazam (IZM) and azoxystrobin (AZT) in cucumbers. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used as the pretreatment procedure. The samples were extracted with acetonitrile and cleaned up with octadecylsilyl silica (C18) and graphite carbon black. The proposed method resulted in satisfactory recovery of IZM and AZT (91.48 to 114.62%), and relative standard deviations were less than 13.1% at fortification concentrations of 1, 20, and 500 μg kg -1 (n = 3). The limits of quantification for IZM and AZT were 0.498 and 0.499 μg kg -1 , respectively, which are far below the maximum residue level (0.5 mg kg -1 ) established for this type of sample. Matrix effects were also evaluated. This study established a sensitive and fast method for the detection of IZM and AZT in cucumber samples.

Simultaneous determination of the quantity and isotopic ratios of uranium in individual micro-particles by isotope dilution thermal ionization mass spectrometry (ID-TIMS).

PubMed

Park, Jong-Ho; Choi, Eun-Ju

2016-11-01

A method to determine the quantity and isotopic ratios of uranium in individual micro-particles simultaneously by isotope dilution thermal ionization mass spectrometry (ID-TIMS) has been developed. This method consists of sequential sample and spike loading, ID-TIMS for isotopic measurement, and application of a series of mathematical procedures to remove the contribution of uranium in the spike. The homogeneity of evaporation and ionization of uranium content was confirmed by the consistent ratio of n((233)U)/n((238)U) determined by TIMS measurements. Verification of the method was performed using U030 solution droplets and U030 particles. Good agreements of resulting uranium quantity, n((235)U)/n((238)U), and n((236)U)/n((238)U) with the estimated or certified values showed the validity of this newly developed method for particle analysis when simultaneous determination of the quantity and isotopic ratios of uranium is required. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a liquid chromatography-tandem mass spectrometry method for the determination of pyridostigmine bromide from guinea pig plasma.

PubMed

Needham, Shane R; Ye, Binying; Smith, J Richard; Korte, William D

2003-11-05

An HPLC/MS/MS method was validated for the low level analysis of pyridostigmine bromide (PB) from guinea pig plasma. An advantage of this strong-cation exchange HPLC/MS/MS method was the enhancement of the ESI-MS signal by providing good retention and good peak shape of PB with a mobile phase of 70% acetonitrile. In addition, the use of 70% acetonitrile in the mobile phase allowed the direct injection of the supernant from the protein precipitated extracted sample. The assay was linear from the range of 0.1 to 50 ng/ml using only 25 microl of sample. The precision and accuracy of the assay was better than 9.1 and 113%, respectively.

Efficient Enrichment and Analysis of Vicinal-Diol-Containing Flavonoid Molecules Using Boronic-Acid-Functionalized Particles and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

PubMed

Kim, Eunjin; Kang, Hyunook; Choi, Insung; Song, Jihyeon; Mok, Hyejung; Jung, Woong; Yeo, Woon-Seok

2018-05-09

Detection and quantitation of flavonoids are relatively difficult compared to those of other small-molecule analytes because flavonoids undergo rapid metabolic processes, resulting in their elimination from the body. Here, we report an efficient enrichment method for facilitating the analysis of vicinal-diol-containing flavonoid molecules using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In our strategy, boronic-acid-functionalized polyacrylamide particles were used, where boronic acids bound to vicinal diols to form boronate monoesters at basic pH. This complex remained intact during the enrichment processes, and the vicinal-diol-containing flavonoids were easily separated by centrifugation and subsequent acidic treatments. The selectivity and limit of detection of our strategy were confirmed by mass spectrometry analysis, and the validity was assessed by performing the detection and quantitation of quercetin in mouse organs.

Zooming In on Plant Hormone Analysis: Tissue- and Cell-Specific Approaches.

PubMed

Novák, Ondřej; Napier, Richard; Ljung, Karin

2017-04-28

Plant hormones are a group of naturally occurring, low-abundance organic compounds that influence physiological processes in plants. Our knowledge of the distribution profiles of phytohormones in plant organs, tissues, and cells is still incomplete, but advances in mass spectrometry have enabled significant progress in tissue- and cell-type-specific analyses of phytohormones over the last decade. Mass spectrometry is able to simultaneously identify and quantify hormones and their related substances. Biosensors, on the other hand, offer continuous monitoring; can visualize local distributions and real-time quantification; and, in the case of genetically encoded biosensors, are noninvasive. Thus, biosensors offer additional, complementary technologies for determining temporal and spatial changes in phytohormone concentrations. In this review, we focus on recent advances in mass spectrometry-based quantification, describe monitoring systems based on biosensors, and discuss validations of the various methods before looking ahead at future developments for both approaches.

Determination of the neuropharmacological drug nodakenin in rat plasma and brain tissues by liquid chromatography tandem mass spectrometry: Application to pharmacokinetic studies.

PubMed

Song, Yingshi; Yan, Huiyu; Xu, Jingbo; Ma, Hongxi

2017-09-01

A rapid and sensitive liquid chromatography tandem mass spectrometry detection using selected reaction monitoring in positive ionization mode was developed and validated for the quantification of nodakenin in rat plasma and brain. Pareruptorin A was used as internal standard. A single step liquid-liquid extraction was used for plasma and brain sample preparation. The method was validated with respect to selectivity, precision, accuracy, linearity, limit of quantification, recovery, matrix effect and stability. Lower limit of quantification of nodakenin was 2.0 ng/mL in plasma and brain tissue homogenates. Linear calibration curves were obtained over concentration ranges of 2.0-1000 ng/mL in plasma and brain tissue homogenates for nodakenin. Intra-day and inter-day precisions (relative standard deviation, RSD) were <15% in both biological media. This assay was successfully applied to plasma and brain pharmacokinetic studies of nodakenin in rats after intravenous administration. Copyright © 2017 John Wiley & Sons, Ltd.

Generation and structural validation of a library of diverse xyloglucan-derived oligosaccharides, including an update on xyloglucan nomenclature.

PubMed

Tuomivaara, Sami T; Yaoi, Katsuro; O'Neill, Malcolm A; York, William S

2015-01-30

Xyloglucans are structurally complex plant cell wall polysaccharides that are involved in cell growth and expansion, energy metabolism, and signaling. Determining the structure-function relationships of xyloglucans would benefit from the availability of a comprehensive and structurally diverse collection of rigorously characterized xyloglucan oligosaccharides. Here, we present a workflow for the semi-preparative scale generation and purification of neutral and acidic xyloglucan oligosaccharides using a combination of enzymatic and chemical treatments and size-exclusion chromatography. Twenty-six of these oligosaccharides were purified to near homogeneity and their structures validated using a combination of matrix-assisted laser desorption/ionization mass spectrometry, high-performance anion exchange chromatography, and 1H nuclear magnetic resonance spectroscopy. Mass spectrometry and analytical chromatography were compared as methods for xyloglucan oligosaccharide quantification. 1H chemical shifts were assigned using two-dimensional correlation spectroscopy. A comprehensive update of the nomenclature describing xyloglucan side-chain structures is provided for reference. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dried blood spot testing for seven steroids using liquid chromatography-tandem mass spectrometry with reference interval determination in the Korean population.

PubMed

Kim, Borahm; Lee, Mi Na; Park, Hyung Doo; Kim, Jong Won; Chang, Yun Sil; Park, Won Soon; Lee, Soo Youn

2015-11-01

Conventional screening for congenital adrenal hyperplasia (CAH) using immunoassays generates a large number of false-positive results. A more specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been introduced to minimize unnecessary follow-ups. However, because of limited data on its use in the Korean population, LC-MS/MS has not yet been incorporated into newborn screening programs in this region. The present study aims to develop and validate an LC-MS/MS method for the simultaneous determination of seven steroids in dried blood spots (DBS) for CAH screening, and to define age-specific reference intervals in the Korean population. We developed and validated an LC-MS/MS method to determine the reference intervals of cortisol, 17-hydroxyprogesterone, 11-deoxycortisol, 21-deoxycortisol, androstenedione, corticosterone, and 11-deoxycorticosterone simultaneously in 453 DBS samples. The samples were from Korean subjects stratified by age group (78 full-term neonates, 76 premature neonates, 89 children, and 100 adults). The accuracy, precision, matrix effects, and extraction recovery were satisfactory for all the steroids at three concentrations; values of intra- and inter-day precision coefficients of variance, bias, and recovery were 0.7-7.7%, -1.5-9.8%, and 49.3-97.5%, respectively. The linearity range was 1-100 ng/mL for cortisol and 0.5-50 ng/mL for other steroids (R²>0.99). The reference intervals were in agreement with the previous reports. This LC-MS/MS method and the reference intervals validated in the Korean population can be successfully applied to analyze seven steroids in DBS for the diagnosis of CAH.

Simultaneous determination of phentermine and topiramate in human plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

PubMed

Ni, Yang; Zhou, Ying; Xu, Mingzhen; He, Xiaomeng; Li, Huqun; Haseeb, Satter; Chen, Hui; Li, Weiyong

2015-03-25

A new method for simultaneous determination of phentermine and topiramate by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching modes was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. Analyses were performed on a liquid chromatography system employing a Kromasil 60-5CN column (2.1 mm × 100 mm, 5 μm) and an isocratic elution with mixed solution of acetonitrile-20mM ammonium formate containing 0.3% formic acid (40:60, v/v), at a flow rate of 0.35 mL/min. Doxazosin mesylate and pioglitazone were used as the internal standard (IS) respectively for quantification. The determination was carried out on an API 4000 triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 150.0/91.0 for phentermine, m/z 452.1/344.3 for doxazosin, and negative m/z 338.3/77.9 for topiramate, m/z 355.0/41.9 for pioglitazone. The method was validated to be linear over the concentration range of 1-800 ng mL(-1) for phentermine, 1-1000 ng mL(-1) for topiramate. Within- and between-day accuracy and precision of the validated method at three different concentration levels were within the acceptable limits of <15% at all concentrations. Blood samples were collected into heparinized tubes before and after administration. The simple and robust LC/MS/MS method was successfully applied for the simultaneous determination of phentermine and topiramate in a pharmacokinetic study in healthy male Chinese volunteers. Copyright © 2015 Elsevier B.V. All rights reserved.

Validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of sulfonamides, trimethoprim and dapsone in muscle, egg, milk and honey.

PubMed

Varenina, Ivana; Bilandžić, Nina; Kolanović, Božica Solomun; Božić, Đurđica; Sedak, Marija; Đokić, Maja; Varga, Ines

2016-01-01

A quantitative multi-residue method that includes 13 sulfonamides, trimethoprim and dapsone was developed and validated according to Commission Decision 2002/657/EC for muscle, milk egg and honey samples. For all matrices, the same extraction procedure was used. Samples were extracted with an acetone/dichloromethane mixture and cleaned up on aromatic sulfonic acid (SO3H) SPE cartridges. After elution and concentration steps, analytes were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data were acquired according to the multiple reaction-monitoring approach (MRM) and analytes were quantified both by the isotope dilution and the matrix-matched approaches calculating the response factors for the scanned product ions. The developed method shows good linearity, specificity, precision (repeatability and within-laboratory reproducibility), and trueness. Estimated CCβ for sulfonamides ranged between 5.6 and 8.2 µg kg(-1) for eggs, between 11.1 and 69.9 µg kg(-1) for milk, between 64.7 and 87.9 µg kg(-1) for muscle, and between 2.7 and 5.3 µg kg(-1) for honey. CCβ values for dapsone were 3.1, 0.6, 0.7 and 1.5 µg kg(-1) and for trimethoprim were 3.1, 6.7, 81.7 and 3.0 µg kg(-1) calculated for eggs, milk, muscle and honey, respectively. Recovery for all matrices was in the range from 89.1% and 109.7%. In matrix effect testing, no significant deviations were found between different samples of muscle and milk; however, a matrix effect was observed when testing different types of honey. The validation results demonstrate that the method is suitable for routine veterinary drug analysis and confirmation of suspect samples.

Liquid chromatography/tandem mass spectrometry method for simultaneous determination of cocaine and its metabolite (-)ecgonine methyl ester in human acidified stabilized plasma samples.

PubMed

Liu, Yongzhen; Zheng, Bo; Strafford, Stephanie; Orugunty, Ravi; Sullivan, Michael; Gus, Jeffrey; Heidbreder, Christian; Fudala, Paul J; Nasser, Azmi

2014-06-15

Two simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methods (low range and high range) were developed and validated for the quantification of cocaine and its metabolite (-)ecgonine methyl ester (EME) in human acidified stabilized plasma samples. In the low range assay, cocaine and the internal standard, cocaine-D3, were extracted using a single step liquid-liquid extraction from human acidified stabilized plasma. For the high range assay, human acidified stabilized plasma containing cocaine, EME, and the internal standards, cocaine-D3 and EME-D3, was mixed with acetonitrile, and the protein precipitate was separated by centrifugation. Both cocaine and EME extracted from both assays were separated on a HILIC column and detected in positive ion mode using multiple reaction monitoring (MRM). Both methods were validated and the specificity, linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries and stability were determined. The linear range for the low range assay was 0.01-5ng/mL for cocaine; in the high range assay values were 5-1000ng/mL for cocaine and 1-200ng/mL for EME. The correlation coefficient (R(2)) values for both assays were 0.993 or greater. The precision and accuracy for intra-day and inter-day were better than 13.0%. The recovery was above 85% and matrix effects were low with the matrix factor ranging from 0.817 to 1.10 for both analytes in both assays. The validated methods were successfully used to quantify the plasma concentrations of cocaine and EME in clinical pharmacokinetic and pharmacodynamic studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of a novel nonfluorinated quinolone, nemonoxacin, in human feces and its glucuronide conjugate in human urine and feces by high-performance liquid chromatography-triple quadrupole mass spectrometry.

PubMed

He, Gaoli; Guo, Beining; Yu, Jicheng; Zhang, Jing; Wu, Xiaojie; Cao, Guoying; Shi, Yaoguo; Tsai, Cheng-Yuan

2015-05-01

Three methods were developed and validated for determination of nemonoxacin in human feces and its major metabolite, nemonoxacin acyl-β- d-glucuronide, in human urine and feces. Nemonoxacin was extracted by liquid-liquid extraction in feces homogenate samples and nemonoxacin acyl-β- d-glucuronide by a solid-phase extraction procedure for pretreatment of both urine and feces homogenate sample. Separation was performed on a C18 reversed-phase column under isocratic elution with the mobile phase consisting of acetonitrile and 0.1% formic acid. Both analytes were determined by liquid chromatography-tandem mass spectrometry with positive electrospray ionization in selected reaction monitoring mode and gatifloxacin as the internal standard. The lower limit of quantitation (LLOQ) of nemonoxacin in feces was 0.12 µg/g and the calibration curve was linear in the concentration range of 0.12-48.00 µg/g. The LLOQ of the metabolite was 0.0010 µg/mL and 0.03 µg/g in urine and feces matrices, while the linear range was 0.0010-0.2000 µg/mL and 0.03-3.00 µg/g, respectively. Validation included selectivity, accuracy, precision, linearity, recovery, matrix effect, carryover, dilution integrity and stability, indicating that the methods can quantify the corresponding analytes with excellent reliability. The validated methods were successfully applied to an absolute bioavailability clinical study of nemonoxacin malate capsule. Copyright © 2014 John Wiley & Sons, Ltd.

Validation of an LC-MS/MS method for the quantification of choline-related compounds and phospholipids in foods and tissues.

PubMed

Xiong, Yeping; Zhao, Yuan-Yuan; Goruk, Sue; Oilund, Kirsten; Field, Catherine J; Jacobs, René L; Curtis, Jonathan M

2012-12-12

A hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC LC-MS/MS) method was developed and validated to simultaneously quantify six aqueous choline-related compounds and eight major phospholipids classes in a single run. HILIC chromatography was coupled to positive ion electrospray mass spectrometry. A combination of multiple scan modes including precursor ion scan, neutral loss scan and multiple reaction monitoring was optimized for the determination of each compound or class in a single LC/MS run. This work developed a simplified extraction scheme in which both free choline and related compounds along with phospholipids were extracted into a homogenized phase using chloroform/methanol/water (1:2:0.8) and diluted into methanol for the analysis of target compounds in a variety of sample matrices. The analyte recoveries were evaluated by spiking tissues and food samples with two isotope-labeled internal standards, PC-d(3) and Cho-d(3). Recoveries of between 90% and 115% were obtained by spiking a range of sample matrices with authentic standards containing all 14 of the target analytes. The precision of the analysis ranged from 1.6% to 13%. Accuracy and precision was comparable to that obtained by quantification of selected phospholipid classes using (31)P NMR. A variety of sample matrices including egg yolks, human diets and animal tissues were analyzed using the validated method. The measurements of total choline in selected foods were found to be in good agreement with values obtained from the USDA choline database. Copyright © 2012 Elsevier B.V. All rights reserved.

Analysis of polonium-210 in food products and bioassay samples by isotope-dilution alpha spectrometry.

PubMed

Lin, Zhichao; Wu, Zhongyu

2009-05-01

A rapid and reliable radiochemical method coupled with a simple and compact plating apparatus was developed, validated, and applied for the analysis of (210)Po in variety of food products and bioassay samples. The method performance characteristics, including accuracy, precision, robustness, and specificity, were evaluated along with a detailed measurement uncertainty analysis. With high Po recovery, improved energy resolution, and effective removal of interfering elements by chromatographic extraction, the overall method accuracy was determined to be better than 5% with measurement precision of 10%, at 95% confidence level.

High-resolution gas chromatography/mass spectrometry method for characterization and quantitative analysis of ginkgolic acids in Ginkgo biloba plants, extracts, and dietary supplements.

PubMed

Wang, Mei; Zhao, Jianping; Avula, Bharathi; Wang, Yan-Hong; Avonto, Cristina; Chittiboyina, Amar G; Wylie, Philip L; Parcher, Jon F; Khan, Ikhlas A

2014-12-17

A high-resolution gas chromatography/mass spectrometry (GC/MS) with selected ion monitor method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts, and commercial products was developed and validated. The method involved sample extraction with (1:1) methanol and 10% formic acid, liquid-liquid extraction with n-hexane, and derivatization with trimethylsulfonium hydroxide (TMSH). Separation of two saturated (C13:0 and C15:0) and six unsaturated ginkgolic acid methyl esters with different positional double bonds (C15:1 Δ8 and Δ10, C17:1 Δ8, Δ10, and Δ12, and C17:2) was achieved on a very polar (88% cyanopropyl) aryl-polysiloxane HP-88 capillary GC column. The double bond positions in the GAs were determined by ozonolysis. The developed GC/MS method was validated according to ICH guidelines, and the quantitation results were verified by comparison with a standard high-performance liquid chromatography method. Nineteen G. biloba authenticated and commercial plant samples and 21 dietary supplements purported to contain G. biloba leaf extracts were analyzed. Finally, the presence of the marker compounds, terpene trilactones and flavonol glycosides for Ginkgo biloba in the dietary supplements was determined by UHPLC/MS and used to confirm the presence of G. biloba leaf extracts in all of the botanical dietary supplements.

Simultaneous identification and quantification of bisphenol A and 12 bisphenol analogues in environmental samples using precolumn derivatization and ultra high performance liquid chromatography with tandem mass spectrometry.

PubMed

Wang, Zhonghe; Yu, Jing; Yao, Jiaxi; Wu, Linlin; Xiao, Hang; Wang, Jun; Gao, Rong

2018-02-10

A method for the identification and quantification of bisphenol A and 12 bisphenol analogues in river water and sediment samples combining liquid-liquid extraction, precolumn derivatization, and ultra high-performance liquid chromatography coupled with tandem mass spectrometry was developed and validated. Analytes were extracted from the river water sample using a liquid-liquid extraction method. Dansyl chloride was selected as a derivatization reagent. Derivatization reaction conditions affecting production of the dansyl derivatives were tested and optimized. All the derivatized target compounds were well separated and eluted in 10 min. Dansyl chloride labeled compounds were analyzed using a high-resolution mass spectrometer with electrospray ionization in the positive mode, and the results were confirmed and quantified in the parallel reaction monitoring mode. The method validation results showed a satisfactory level of sensitivity. Linearity was assessed using matrix-matched standard calibration, and good correlation coefficients were obtained. The limits of quantification for the analytes ranged from 0.005 to 0.02 ng/mL in river water and from 0.15 to 0.80 ng/g in sediment. Good reproducibility of the method in terms of intra- and interday precision was achieved, yielding relative standard deviations of less than 10.1 and 11.6%, respectively. Finally, this method was successfully applied to the analysis of real samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mass spectrometry as a quantitative tool in plant metabolomics

PubMed Central

Jorge, Tiago F.; Mata, Ana T.

2016-01-01

Metabolomics is a research field used to acquire comprehensive information on the composition of a metabolite pool to provide a functional screen of the cellular state. Studies of the plant metabolome include the analysis of a wide range of chemical species with very diverse physico-chemical properties, and therefore powerful analytical tools are required for the separation, characterization and quantification of this vast compound diversity present in plant matrices. In this review, challenges in the use of mass spectrometry (MS) as a quantitative tool in plant metabolomics experiments are discussed, and important criteria for the development and validation of MS-based analytical methods provided. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644967

Good quantification practices of flavours and fragrances by mass spectrometry.

PubMed

Begnaud, Frédéric; Chaintreau, Alain

2016-10-28

Over the past 15 years, chromatographic techniques with mass spectrometric detection have been increasingly used to monitor the rapidly expanded list of regulated flavour and fragrance ingredients. This trend entails a need for good quantification practices suitable for complex media, especially for multi-analytes. In this article, we present experimental precautions needed to perform the analyses and ways to process the data according to the most recent approaches. This notably includes the identification of analytes during their quantification and method validation, when applied to real matrices, based on accuracy profiles. A brief survey of application studies based on such practices is given.This article is part of the themed issue 'Quantitative mass spectrometry'. © 2016 The Authors.

Determination of virginiamycin M1 residue in tissues of swine and chicken by ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Wang, Xiaoyang; Wang, Mi; Zhang, Keyu; Hou, Ting; Zhang, Lifang; Fei, Chenzong; Xue, Feiqun; Hang, Taijun

2018-06-01

A reliable UPLC-MS/MS method with high sensitivity was developed and validated for the determination of virginiamycin M1 in muscle, fat, liver, and kidney samples of chicken and swine. Analytes were extracted using acetonitrile and extracts were defatted by N-hexane. Chromatographic separation was performed on a BEH C18 liquid chromatography column. The analytes were then detected using triplequadrupole mass spectrometry in positive electrospray ionization and multiple reaction monitoring mode. Calibration plots were constructed using standard working solutions and showed good linearity. Limits of quantification ranged from 2 to 60 ng mL -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Study of odor recorder using Mass Spectrometry

NASA Astrophysics Data System (ADS)

Miura, Tomohiro; Nakamoto, Takamichi; Moriizumi, Toyosaka

It is necessary to determine the recipe of a target odor with sufficient accuracy to realize an odor recorder for recording and reproducing it. We studied the recipe measurement method of a target odor using a mass spectrometry. It was confirmed that the linear superposition was valid when the binary mixture of the apple-flavor components such as isobutyric acid and ethyl valerate was measured. The superposition of a mass spectrum pattern may enable the recipe determination of a multi-component odor easily. In this research, we succeeded in the recipe determinations of orange flavor made up of 14 component odors when its typical recipe, the equalized, the citral-enhanced and the citronellol-enhanced ones were measured.

Method validation using weighted linear regression models for quantification of UV filters in water samples.

PubMed

da Silva, Claudia Pereira; Emídio, Elissandro Soares; de Marchi, Mary Rosa Rodrigues

2015-01-01

This paper describes the validation of a method consisting of solid-phase extraction followed by gas chromatography-tandem mass spectrometry for the analysis of the ultraviolet (UV) filters benzophenone-3, ethylhexyl salicylate, ethylhexyl methoxycinnamate and octocrylene. The method validation criteria included evaluation of selectivity, analytical curve, trueness, precision, limits of detection and limits of quantification. The non-weighted linear regression model has traditionally been used for calibration, but it is not necessarily the optimal model in all cases. Because the assumption of homoscedasticity was not met for the analytical data in this work, a weighted least squares linear regression was used for the calibration method. The evaluated analytical parameters were satisfactory for the analytes and showed recoveries at four fortification levels between 62% and 107%, with relative standard deviations less than 14%. The detection limits ranged from 7.6 to 24.1 ng L(-1). The proposed method was used to determine the amount of UV filters in water samples from water treatment plants in Araraquara and Jau in São Paulo, Brazil. Copyright © 2014 Elsevier B.V. All rights reserved.

Simple and rapid quantification of brominated vegetable oil in commercial soft drinks by LC–MS

PubMed Central

Chitranshi, Priyanka; da Costa, Gonçalo Gamboa

2016-01-01

We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography–electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple “dilute and shoot” sample preparation. The quantification is conducted by mass spectrometry in selected ion recording mode and a single point standard addition procedure. The method was validated in the range of 5–25 μg/mL BVO, encompassing the legal limit of 15 μg/mL established by the US FDA for fruit-flavored beverages in the US market. The method was characterized by excellent intra- and inter-assay accuracy (97.3–103.4%) and very low imprecision [0.5–3.6% (RSD)]. The direct nature of the quantification, simplicity, and excellent statistical performance of this methodology constitute clear advantages in relation to previously published methods for the analysis of BVO in soft drinks. PMID:27451219

An ultra-high pressure liquid chromatography-tandem mass spectrometry method for the quantification of teicoplanin in plasma of neonates.

PubMed

Begou, O; Kontou, A; Raikos, N; Sarafidis, K; Roilides, E; Papadoyannis, I N; Gika, H G

2017-03-15

The development and validation of an ultra-high pressure liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method was performed with the aim to be applied for the quantification of plasma teicoplanin concentrations in neonates. Pharmacokinetic data of teicoplanin in the neonatal population is very limited, therefore, a sensitive and reliable method for the determination of all isoforms of teicoplanin applied in a low volume of sample is of real importance. Teicoplanin main components were extracted by a simple acetonitrile precipitation step and analysed on a C18 chromatographic column by a triple quadrupole MS with electrospray ionization. The method provides quantitative data over a linear range of 25-6400ng/mL with LOD 8.5ng/mL and LOQ 25ng/mL for total teicoplanin. The method was applied in plasma samples from neonates to support pharmacokinetic data and proved to be a reliable and fast method for the quantification of teicoplanin concentration levels in plasma of infants during therapy in Intensive Care Unit. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of on-line desalter-inductively coupled plasma-mass spectrometry system for determination of Cr(III), Cr(VI), and total chromium concentrations in natural water and urine samples

NASA Astrophysics Data System (ADS)

Sun, Y. C.; Lin, C. Y.; Wu, S. F.; Chung, Y. T.

2006-02-01

We have developed a simple and convenient method for the determination of Cr(III), Cr(VI), and the total chromium concentrations in natural water and urine samples that use a flow injection on-line desalter-inductively coupled plasma-mass spectrometry system. When using aqueous ammonium chloride (pH 8) as the stripping solution, the severe interference from sodium in the matrix can be eliminated prior to inductively coupled plasma-mass spectrometry measurement, and the Cr(VI) level can be determined directly. To determine the total concentration of Cr in natural water and urine samples, we used H 2O 2 or HNO 3 to decompose the organic matter and convert all chromium species into the Cr(VI) oxidation state. To overcome the spectral interference caused by the matrix chloride ion in the resulting solutions, we employed cool plasma to successfully suppress chloride-based molecular ion interference during the inductively coupled plasma-mass spectrometry measurement. By significantly eliminating interference from the cationic and anionic components in the matrices prior to the inductively coupled plasma-mass spectrometry measurement, we found that the detection limit reached 0.18 μg L - 1 (based on 3 sigma). We validated this method through the analysis of the total chromium content in two reference materials (NIST 1643c and 2670E) and through measuring the recovery in spiked samples.

Rapid multiplexed genotyping for hereditary thrombophilia by SELDI-TOF mass spectrometry.

PubMed

Yang, Shangbin; Xu, Lihui; Wu, Haifeng M

2010-03-01

Approximately 50% of patients with venous thromboembolism also present with hereditary predisposition. The most common genetic factors are single nucleotide polymorphisms (SNPs) of factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T. Genotyping these SNPs helps clinicians to correctly diagnose the disease and properly manage patients. In this study, we report a novel method using surface-enhanced laser desorption and ionization time of flight mass spectrometry to rapidly genotype, in a multiplex fashion, 3 SNPs that predispose patients to thrombosis. First, patient DNA samples were subjected to polymerase chain reaction to amplify and extend the DNA products with masses corresponding to specific genotypes. Polymerase chain reaction products were then applied to Q10 anionic protein chips, undergoing on-chip sample enrichment and clean-up. Finally, the genotypes of the SNPs were determined by surface-enhanced laser desorption and ionization time of flight mass spectrometry. This method offers a rapid turnaround time of less than 5 hours from sample collection to result reporting. The analytical accuracy of each SNP genotyping result has been confirmed by DNA sequencing. In addition, the genotype results produced by this method were validated by comparing them with results obtained by the approved method in the clinical reference laboratory. This novel method is fast, accurate, and reproducible, and thus provides an excellent platform to promote personalized medicine in the management of clotting disorders.

Generic sample preparation combined with high-resolution liquid chromatography-time-of-flight mass spectrometry for unification of urine screening in doping-control laboratories.

PubMed

Peters, R J B; Oosterink, J E; Stolker, A A M; Georgakopoulos, C; Nielen, M W F

2010-04-01

A unification of doping-control screening procedures of prohibited small molecule substances--including stimulants, narcotics, steroids, beta2-agonists and diuretics--is highly urgent in order to free resources for new classes such as banned proteins. Conceptually this may be achieved by the use of a combination of one gas chromatography-time-of-flight mass spectrometry method and one liquid chromatography-time-of-flight mass spectrometry method. In this work a quantitative screening method using high-resolution liquid chromatography in combination with accurate-mass time-of-flight mass spectrometry was developed and validated for determination of glucocorticosteroids, beta2-agonists, thiazide diuretics, and narcotics and stimulants in urine. To enable the simultaneous isolation of all the compounds of interest and the necessary purification of the resulting extracts, a generic extraction and hydrolysis procedure was combined with a solid-phase extraction modified for these groups of compounds. All 56 compounds are determined using positive electrospray ionisation with the exception of the thiazide diuretics for which the best sensitivity was obtained by using negative electrospray ionisation. The results show that, with the exception of clenhexyl, procaterol, and reproterol, all compounds can be detected below the respective minimum required performance level and the results for linearity, repeatability, within-lab reproducibility, and accuracy show that the method can be used for quantitative screening. If qualitative screening is sufficient the instrumental analysis may be limited to positive ionisation, because all analytes including the thiazides can be detected at the respective minimum required levels in the positive mode. The results show that the application of accurate-mass time-of-flight mass spectrometry in combination with generic extraction and purification procedures is suitable for unification and expansion of the window of screening methods of doping laboratories. Moreover, the full-scan accurate-mass data sets obtained still allow retrospective examination for emerging doping agents, without re-analyzing the samples.

Analysis of Ergot Alkaloids

PubMed Central

Crews, Colin

2015-01-01

The principles and application of established and newer methods for the quantitative and semi-quantitative determination of ergot alkaloids in food, feed, plant materials and animal tissues are reviewed. The techniques of sampling, extraction, clean-up, detection, quantification and validation are described. The major procedures for ergot alkaloid analysis comprise liquid chromatography with tandem mass spectrometry (LC-MS/MS) and liquid chromatography with fluorescence detection (LC-FLD). Other methods based on immunoassays are under development and variations of these and minor techniques are available for specific purposes. PMID:26046699

Determination of 20 trace elements and arsenic species for a realgar-containing traditional Chinese medicine Niuhuang Jiedu tablets by direct inductively coupled plasma-mass spectrometry and high performance liquid chromatography-inductively coupled plasma-mass spectrometry.

PubMed

Jin, Pengfei; Liang, Xiaoli; Xia, Lufeng; Jahouh, Farid; Wang, Rong; Kuang, Yongmei; Hu, Xin

2016-01-01

Niuhuang Jiedu tablet (NHJDT) is a realgar-containing traditional Chinese medicine. A direct inductively coupled plasma-mass spectrometry (ICP-MS) method for the simultaneous determination of 20 trace elements (Mg, K, Ca, Na, Fe, As, Zn, Sr, Ba, Cu, Mn, Ni, Pb, V, Cr, Se, Co, Mo, Cd, Hg) in NHJDT, as well as in water, gastric fluid and intestinal fluid was established. Meanwhile, a high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) method was developed for the determination of arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and for the identification of arsenobetaine (AsB) and arsenocholine (AsC) in these extracts. Both methods were fully validated in the respect of linearity, sensitivity, precision, stability and accuracy. The reliability of the ICP-MS method was further evaluated using a certified standard reference material prepared from dried tomato leaves (NIST, SRM 1572a). The analysis showed that some manufacturers formulated lower amount of realgar than required in the Chinese Pharmacopoeia (ChP) in their preparations. In addition, almost same extraction profiles for total As and inorganic As were found in water and in gastrointestinal fluids, while higher extraction rates for other 19 elements were observed in gastrointestinal fluids. Our findings show that the toxicities of Hg, Cu, Cd and Pb in NHJDP are low, while the real As toxicity in NHJDT should be deeply investigated. Copyright © 2015 Elsevier GmbH. All rights reserved.

Development and validation of a method for mercury determination in seawater for the process control of a candidate certified reference material.

PubMed

Sánchez, Raquel; Snell, James; Held, Andrea; Emons, Hendrik

2015-08-01

A simple, robust and reliable method for mercury determination in seawater matrices based on the combination of cold vapour generation and inductively coupled plasma mass spectrometry (CV-ICP-MS) and its complete in-house validation are described. The method validation covers parameters such as linearity, limit of detection (LOD), limit of quantification (LOQ), trueness, repeatability, intermediate precision and robustness. A calibration curve covering the whole working range was achieved with coefficients of determination typically higher than 0.9992. The repeatability of the method (RSDrep) was 0.5 %, and the intermediate precision was 2.3 % at the target mass fraction of 20 ng/kg. Moreover, the method was robust with respect to the salinity of the seawater. The limit of quantification was 2.7 ng/kg, which corresponds to 13.5 % of the target mass fraction in the future certified reference material (20 ng/kg). An uncertainty budget for the measurement of mercury in seawater has been established. The relative expanded (k = 2) combined uncertainty is 6 %. The performance of the validated method was demonstrated by generating results for process control and a homogeneity study for the production of a candidate certified reference material.

Cross validation of gas chromatography-flame photometric detection and gas chromatography-mass spectrometry methods for measuring dialkylphosphate metabolites of organophosphate pesticides in human urine.

PubMed

Prapamontol, Tippawan; Sutan, Kunrunya; Laoyang, Sompong; Hongsibsong, Surat; Lee, Grace; Yano, Yukiko; Hunter, Ronald Elton; Ryan, P Barry; Barr, Dana Boyd; Panuwet, Parinya

2014-01-01

We report two analytical methods for the measurement of dialkylphosphate (DAP) metabolites of organophosphate pesticides in human urine. These methods were independently developed/modified and implemented in two separate laboratories and cross validated. The aim was to develop simple, cost effective, and reliable methods that could use available resources and sample matrices in Thailand and the United States. While several methods already exist, we found that direct application of these methods required modification of sample preparation and chromatographic conditions to render accurate, reliable data. The problems encountered with existing methods were attributable to urinary matrix interferences, and differences in the pH of urine samples and reagents used during the extraction and derivatization processes. Thus, we provide information on key parameters that require attention during method modification and execution that affect the ruggedness of the methods. The methods presented here employ gas chromatography (GC) coupled with either flame photometric detection (FPD) or electron impact ionization-mass spectrometry (EI-MS) with isotopic dilution quantification. The limits of detection were reported from 0.10ng/mL urine to 2.5ng/mL urine (for GC-FPD), while the limits of quantification were reported from 0.25ng/mL urine to 2.5ng/mL urine (for GC-MS), for all six common DAP metabolites (i.e., dimethylphosphate, dimethylthiophosphate, dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and diethyldithiophosphate). Each method showed a relative recovery range of 94-119% (for GC-FPD) and 92-103% (for GC-MS), and relative standard deviations (RSD) of less than 20%. Cross-validation was performed on the same set of urine samples (n=46) collected from pregnant women residing in the agricultural areas of northern Thailand. The results from split sample analysis from both laboratories agreed well for each metabolite, suggesting that each method can produce comparable data. In addition, results from analyses of specimens from the German External Quality Assessment Scheme (G-EQUAS) suggested that the GC-FPD method produced accurate results that can be reasonably compared to other studies. Copyright © 2013 Elsevier GmbH. All rights reserved.

Surrogate analyte approach for quantitation of endogenous NAD(+) in human acidified blood samples using liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

PubMed

Liu, Liling; Cui, Zhiyi; Deng, Yuzhong; Dean, Brian; Hop, Cornelis E C A; Liang, Xiaorong

2016-02-01

A high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the quantitative determination of NAD(+) in human whole blood using a surrogate analyte approach was developed and validated. Human whole blood was acidified using 0.5N perchloric acid at a ratio of 1:3 (v:v, blood:perchloric acid) during sample collection. 25μL of acidified blood was extracted using a protein precipitation method and the resulting extracts were analyzed using reverse-phase chromatography and positive electrospray ionization mass spectrometry. (13)C5-NAD(+) was used as the surrogate analyte for authentic analyte, NAD(+). The standard curve ranging from 0.250 to 25.0μg/mL in acidified human blood for (13)C5-NAD(+) was fitted to a 1/x(2) weighted linear regression model. The LC-MS/MS response between surrogate analyte and authentic analyte at the same concentration was obtained before and after the batch run. This response factor was not applied when determining the NAD(+) concentration from the (13)C5-NAD(+) standard curve since the percent difference was less than 5%. The precision and accuracy of the LC-MS/MS assay based on the five analytical QC levels were well within the acceptance criteria from both FDA and EMA guidance for bioanalytical method validation. Average extraction recovery of (13)C5-NAD(+) was 94.6% across the curve range. Matrix factor was 0.99 for both high and low QC indicating minimal ion suppression or enhancement. The validated assay was used to measure the baseline level of NAD(+) in 29 male and 21 female human subjects. This assay was also used to study the circadian effect of endogenous level of NAD(+) in 10 human subjects. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparative Validation of the Determination of Sofosbuvir in Pharmaceuticals by Several Inexpensive Ecofriendly Chromatographic, Electrophoretic, and Spectrophotometric Methods.

PubMed

El-Yazbi, Amira F

2017-07-01

Sofosbuvir (SOFO) was approved by the U.S. Food and Drug Administration in 2013 for the treatment of hepatitis C virus infection with enhanced antiviral potency compared with earlier analogs. Notwithstanding, all current editions of the pharmacopeias still do not present any analytical methods for the quantification of SOFO. Thus, rapid, simple, and ecofriendly methods for the routine analysis of commercial formulations of SOFO are desirable. In this study, five accurate methods for the determination of SOFO in pharmaceutical tablets were developed and validated. These methods include HPLC, capillary zone electrophoresis, HPTLC, and UV spectrophotometric and derivative spectrometry methods. The proposed methods proved to be rapid, simple, sensitive, selective, and accurate analytical procedures that were suitable for the reliable determination of SOFO in pharmaceutical tablets. An analysis of variance test with P-value > 0.05 confirmed that there were no significant differences between the proposed assays. Thus, any of these methods can be used for the routine analysis of SOFO in commercial tablets.

Development and validation of a streamlined method designed to detech residues of 62 veterinary drugs in bovine kidney using ultrahigh performance liquid chromatography - tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

In the USA, the US Department of Agriculture’s Food Safety Inspection Service (FSIS) conducts the National Residue Program designed to monitor veterinary drug and other chemical residues in beef and other slaughtered food animals. Currently, FSIS uses a 7-plate bioassay in the laboratory to screen f...

Determination of lead, cadmium and mercury in blood for assessment of environmental exposure: A comparison between inductively coupled plasma mass spectrometry and atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Palmer, Christopher D.; Lewis, Miles E.; Geraghty, Ciaran M.; Barbosa, Fernando; Parsons, Patrick J.

2006-08-01

A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 μl of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 μg dl - 1 for Pb, 0.09 μg l - 1 for Cd; and 0.17 μg l - 1 for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 μg dl - 1 , 0.54 μg l - 1 , and 0.6 μg l - 1 , for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (a) the New York State Department of Health's Wadsworth Center, Albany, NY, USA (b) L'Institut National de Santé Publique du Québec, Centre de Toxicologie du Québec, Canada, (c) Friedrich-Alexander University, Erlangen, Germany, and (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

Determination of perfluorinated compounds in fish fillet homogenates: method validation and application to fillet homogenates from the Mississippi River.

PubMed

Malinsky, Michelle Duval; Jacoby, Cliffton B; Reagen, William K

2011-01-10

We report herein a simple protein precipitation extraction-liquid chromatography tandem mass spectrometry (LC/MS/MS) method, validation, and application for the analysis of perfluorinated carboxylic acids (C7-C12), perfluorinated sulfonic acids (C4, C6, and C8), and perfluorooctane sulfonamide (FOSA) in fish fillet tissue. The method combines a rapid homogenization and protein precipitation tissue extraction procedure using stable-isotope internal standard (IS) calibration. Method validation in bluegill (Lepomis macrochirus) fillet tissue evaluated the following: (1) method accuracy and precision in both extracted matrix-matched calibration and solvent (unextracted) calibration, (2) quantitation of mixed branched and linear isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) with linear isomer calibration, (3) quantitation of low level (ppb) perfluorinated compounds (PFCs) in the presence of high level (ppm) PFOS, and (4) specificity from matrix interferences. Both calibration techniques produced method accuracy of at least 100±13% with a precision (%RSD) ≤18% for all target analytes. Method accuracy and precision results for fillet samples from nine different fish species taken from the Mississippi River in 2008 and 2009 are also presented. Copyright © 2010 Elsevier B.V. All rights reserved.

Determination of Inorganic Arsenic in a Wide Range of Food Matrices using Hydride Generation - Atomic Absorption Spectrometry.

PubMed

de la Calle, Maria B; Devesa, Vicenta; Fiamegos, Yiannis; Vélez, Dinoraz

2017-09-01

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to inorganic arsenic through diet, information about distribution of arsenic species in various food types must be generated. A method, previously validated in a collaborative trial, has been applied to determine inorganic arsenic in a wide variety of food matrices, covering grains, mushrooms and food of marine origin (31 samples in total). The method is based on detection by flow injection-hydride generation-atomic absorption spectrometry of the iAs selectively extracted into chloroform after digestion of the proteins with concentrated HCl. The method is characterized by a limit of quantification of 10 µg/kg dry weight, which allowed quantification of inorganic arsenic in a large amount of food matrices. Information is provided about performance scores given to results obtained with this method and which were reported by different laboratories in several proficiency tests. The percentage of satisfactory results obtained with the discussed method is higher than that of the results obtained with other analytical approaches.

Development of a liquid chromatography-tandem mass spectrometry method for quantitative analysis of trace d-amino acids.

PubMed

Nakano, Yosuke; Konya, Yutaka; Taniguchi, Moyu; Fukusaki, Eiichiro

2017-01-01

d-Amino acids have recently attracted much attention in various research fields including medical, clinical and food industry due to their important biological functions that differ from l-amino acid. Most chiral amino acid separation techniques require complicated derivatization procedures in order to achieve the desirable chromatographic behavior and detectability. Thus, the aim of this research is to develop a highly sensitive analytical method for the enantioseparation of chiral amino acids without any derivatization process using liquid chromatography-tandem mass spectrometry (LC-MS/MS). By optimizing MS/MS parameters, we established a quantification method that allowed the simultaneous analysis of 18 d-amino acids with high sensitivity and reproducibility. Additionally, we applied the method to food sample (vinegar) for the validation, and successfully quantified trace levels of d-amino acids in samples. These results demonstrated the applicability and feasibility of the LC-MS/MS method as a novel, effective tool for d-amino acid measurement in various biological samples. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Determination of molindone enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry using macrocyclic antibiotic chiral stationary phases.

PubMed

Jiang, Hongliang; Li, Yinghe; Pelzer, Mary; Cannon, Michelle J; Randlett, Christopher; Junga, Heiko; Jiang, Xiangyu; Ji, Qin C

2008-05-30

A sensitive and selective bioanalytical assay was developed and validated for the determination of enantiomeric molindone in human plasma using high-performance liquid chromatography-tandem mass spectrometry along with supported liquid extraction procedures. The chiral separation was evaluated and optimized on macrocyclic antibiotic type chiral stationary phases (CSPs) based on teicoplanin aglycone (Chirobiotic TAG) in polar organic, polar ionic, and reversed-phase mode chromatography, respectively. Complete baseline separation was achieved on a Chirobiotic TAG column under isocratic condition in reversed-phase chromatography. The method validation was conducted using a Chirobiotic TAG column (100 mm x 2.1 mm) over the curve range 0.100-100 ng/ml for each molindone enantiomer using 0.0500 ml of plasma sample. The flow rate was 0.8 ml/min and the total run time was 9 min. Supported liquid extraction in a 96-well plate format was used for sample preparation. Parameters including recovery, matrix effect, linearity, sensitivity, specificity, carryover, precision, accuracy, dilution integrity, and stability were evaluated. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels were RSD

Simultaneous determination of dextromethorphan, dextrorphan, and guaifenesin in human plasma using semi-automated liquid/liquid extraction and gradient liquid chromatography tandem mass spectrometry.

PubMed

Eichhold, Thomas H; McCauley-Myers, David L; Khambe, Deepa A; Thompson, Gary A; Hoke, Steven H

2007-01-17

A method for the simultaneous determination of dextromethorphan (DEX), dextrorphan (DET), and guaifenesin (GG) in human plasma was developed, validated, and applied to determine plasma concentrations of these compounds in samples from six clinical pharmacokinetic (PK) studies. Semi-automated liquid handling systems were used to perform the majority of the sample manipulation including liquid/liquid extraction (LLE) of the analytes from human plasma. Stable-isotope-labeled analogues were utilized as internal standards (ISTDs) for each analyte to facilitate accurate and precise quantification. Extracts were analyzed using gradient liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Use of semi-automated LLE with LC-MS/MS proved to be a very rugged and reliable approach for analysis of more than 6200 clinical study samples. The lower limit of quantification was validated at 0.010, 0.010, and 1.0 ng/mL of plasma for DEX, DET, and GG, respectively. Accuracy and precision of quality control (QC) samples for all three analytes met FDA Guidance criteria of +/-15% for average QC accuracy with coefficients of variation less than 15%. Data from the thorough evaluation of the method during development, validation, and application are presented to characterize selectivity, linearity, over-range sample analysis, accuracy, precision, autosampler carry-over, ruggedness, extraction efficiency, ionization suppression, and stability. Pharmacokinetic data are also provided to illustrate improvements in systemic drug and metabolite concentration-time profiles that were achieved by formulation optimization.

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

A novel ultra performance liquid chromatography-tandem mass spectrometry method for the determination of sucrose octasulfate in dog plasma.

PubMed

Ke, Yuyong; Li, Steve Lianghong; Chang, Linda Dongxia; Kapanadze, Theo

2015-01-26

A novel, specific and sensitive bioanalytical method has been developed for the determination of sucrose octasulfate (SOS) in dog plasma and urine using ion-pair reversed-phase ultraperformance liquid chromatography coupled with electrospray triple quadruple mass spectrometry (IPRP-UPLC ESI MS/MS). (13)C-labeled sucrose octasulfate-(13)C12 sodium salt is used as the internal standard. 200 μL of plasma or serum sample is extracted using weak anion exchange solid phase cartridge. In this method, a polar amide column is employed for the liquid chromatograph (LC) separation while the diethylamine and formic acid buffer is used as the ion-pairing reagent. The low limitation of quantitation of sucrose octasulfate is 0.20 ng on the column with a signal to noise ratio larger than 50. Parameters such as linearity, accuracy and precision have been validated in full compliance with the FDA guidelines for the bioanalytical method development and validation. A linear regression model fit the calibration curve very well with R>0.99. The bias and coefficient of variation of all levels of QCs are within the range of 15%. The selectivity, matrix effect and stabilities of analytes in solution and matrix have also been evaluated and the results met the acceptance criteria according to the guidelines. Based on these results, the method has qualified to analyze sucrose octasulfate in dog plasma for clinic research. This method has been applied to 1000 preclinical samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioanalytical method development and validation for the determination of glycine in human cerebrospinal fluid by ion-pair reversed-phase liquid chromatography-tandem mass spectrometry.

PubMed

Jiang, Jian; James, Christopher A; Wong, Philip

2016-09-05

A LC-MS/MS method has been developed and validated for the determination of glycine in human cerebrospinal fluid (CSF). The validated method used artificial cerebrospinal fluid as a surrogate matrix for calibration standards. The calibration curve range for the assay was 100-10,000ng/mL and (13)C2, (15)N-glycine was used as an internal standard (IS). Pre-validation experiments were performed to demonstrate parallelism with surrogate matrix and standard addition methods. The mean endogenous glycine concentration in a pooled human CSF determined on three days by using artificial CSF as a surrogate matrix and the method of standard addition was found to be 748±30.6 and 768±18.1ng/mL, respectively. A percentage difference of -2.6% indicated that artificial CSF could be used as a surrogate calibration matrix for the determination of glycine in human CSF. Quality control (QC) samples, except the lower limit of quantitation (LLOQ) QC and low QC samples, were prepared by spiking glycine into aliquots of pooled human CSF sample. The low QC sample was prepared from a separate pooled human CSF sample containing low endogenous glycine concentrations, while the LLOQ QC sample was prepared in artificial CSF. Standard addition was used extensively to evaluate matrix effects during validation. The validated method was used to determine the endogenous glycine concentrations in human CSF samples. Incurred sample reanalysis demonstrated reproducibility of the method. Copyright © 2016 Elsevier B.V. All rights reserved.

Estimation of terpene content in loblolly pine biomass using a hybrid fast-GC and pyrolysis-molecular beam mass spectrometry method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harman-Ware, Anne E.; Davis, Mark F.; Peter, Gary F.

Terpenes can be used as renewable fuels and chemicals and quantifying their presence in biomass is becoming increasingly important. A novel method was developed to rapidly quantify total diterpenoid resin acids using pyrolysis-molecular beam mass spectrometry (py-MBMS). Pine sapling monoterpenes and diterpenoids were extracted from wood using a 1:1 (v/v) mixture of hexane and acetone and analyses were performed before and after extraction to determine the extraction efficiency of the solvent system. The resulting extract was analyzed for total diterpenoid content using py-MBMS and was combined with total monoterpene content that was determined using a low thermal mass modular acceleratedmore » column heater (LTM MACH) fast-GC/FID to measure the terpene content present in pine saplings. Oleoresin extruded from larger pine trees was used to validate mass balance closure of the terpene content in the extract solvent.« less

Targeted profiling of hydrophilic constituents of royal jelly by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

PubMed

Pina, Athanasia; Begou, Olga; Kanelis, Dimitris; Gika, Helen; Kalogiannis, Stavros; Tananaki, Chrysoula; Theodoridis, Georgios; Zotou, Anastasia

2018-01-05

In the present work a Hydrophilic Interaction Liquid Chromatography-tandem Mass Spectrometry (HILIC-MS/MS) method was developed for the efficient separation and quantification of a large number of small polar bioactive molecules in Royal Jelly. The method was validated and provided satisfactory detection sensitivity for 88 components. Quantification was proven to be precise for 64 components exhibiting good linearity, recoveries R% >90% for the majority of analytes and intra- and inter-day precision from 0.14 to 20% RSD. Analysis of 125 fresh royal jelly samples of Greek origin provided useful information on royal jelly's hydrophilic bioactive components revealing lysine, ribose, proline, melezitose and glutamic acid to be in high abundance. In addition the occurrence of 18 hydrophilic nutrients which have not been reported previously as royal jelly constituents is shown. Copyright © 2017 Elsevier B.V. All rights reserved.

Silymarin in liposomes and ethosomes: pharmacokinetics and tissue distribution in free-moving rats by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Chang, Li-Wen; Hou, Mei-Ling; Tsai, Tung-Hu

2014-12-03

The aim of this study was to prepare silymarin formulations (silymarin entrapped in liposomes and ethosomes, formulations referred to as LSM and ESM, respectively) to improve oral bioavailability of silymarin and evaluate its tissue distribution by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in free-moving rats. Silibinin is the major active constituent of silymarin, which is the main component to be analyzed. A rapid, sensitive, and repeatable LC-MS/MS method was developed and validated in terms of precision, accuracy, and extraction recovery. Furthermore, the established method was applied to study the pharmacokinetics and tissue distribution of silymarin in rats. The size, ζ potential, and drug release of the formulations were characterized. These results showed that the LSM and ESM encapsulated formulations of silymarin may provide more efficient tissue distribution and increased oral bioavailability, thus improving its therapeutic bioactive properties in the body.

Estimation of terpene content in loblolly pine biomass using a hybrid fast-GC and pyrolysis-molecular beam mass spectrometry method

DOE PAGES

Harman-Ware, Anne E.; Davis, Mark F.; Peter, Gary F.; ...

2017-01-16

Terpenes can be used as renewable fuels and chemicals and quantifying their presence in biomass is becoming increasingly important. A novel method was developed to rapidly quantify total diterpenoid resin acids using pyrolysis-molecular beam mass spectrometry (py-MBMS). Pine sapling monoterpenes and diterpenoids were extracted from wood using a 1:1 (v/v) mixture of hexane and acetone and analyses were performed before and after extraction to determine the extraction efficiency of the solvent system. The resulting extract was analyzed for total diterpenoid content using py-MBMS and was combined with total monoterpene content that was determined using a low thermal mass modular acceleratedmore » column heater (LTM MACH) fast-GC/FID to measure the terpene content present in pine saplings. Oleoresin extruded from larger pine trees was used to validate mass balance closure of the terpene content in the extract solvent.« less

Procedure for detecting and confirming pentobarbital residues in dog food by gas chromatography/mass spectrometry.

PubMed

Adam, L A; Reeves, V B

1998-01-01

The method described detects and confirms presence of pentobarbital residues in dry, extruded feeds at concentrations of 5-20 ppb. Dried feed is ground to a uniform powder and shaken overnight in methanol. A portion of the methanolic extract is evaporated, and the residue is reconstituted in phosphate-buffered saline. The aqueous extract is cleaned with a solid-phase extraction cartridge designed to extract barbiturate residues from biological matrixes. Dimethyl sulfoxide, tetramethylammonium hydroxide, and iodomethane are added to derivatize pentobarbital, 1,3-Dimethyl-pentobarbital is then acidified with dilute hydrochloric acid and extracted with isooctane. The organic layer is transferred and evaporated under a stream of nitrogen. The residue is reconstituted in a small volume of ethyl acetate for analysis by gas chromatography/mass spectrometry. The limit of detection is approximately 0.7 ppb. The method was validated with pentobarbital-fortified feed samples containing high concentrations of meat and bone meal.

High-performance liquid chromatography-electrospray ionization mass spectrometry determination of sodium ferulate in human plasma.

PubMed

Yang, Cheng; Tian, Yuan; Zhang, Zunjian; Xu, Fengguo; Chen, Yun

2007-02-19

A selective and sensitive high-performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the determination of sodium ferulate in human plasma. The sample preparation was a liquid-liquid extraction and chromatographic separation was achieved with an Agilent ZORBAX SB-C(18) (3.5 microm, 100 mm x 3.0 mm) column, using a mobile phase of methanol-0.05% acetic acid 40:60 (v/v). Standard curves were linear (r(2)=0.9982) over the concentration range of 0.007-4.63 nM/ml and had acceptable accuracy and precision. The within- and between-batch precisions were within 12% relative standard deviation. The lower limit of quantification (LLOQ) was 0.007 nM/ml. The validated HPLC-ESI-MS method has been used successfully to study sodium ferulate pharmacokinetics, bioavailability and bioequivalence in 20 healthy volunteers.

Mass spectrometry based biomarker discovery, verification, and validation--quality assurance and control of protein biomarker assays.

PubMed

Parker, Carol E; Borchers, Christoph H

2014-06-01

In its early years, mass spectrometry (MS)-based proteomics focused on the cataloging of proteins found in different species or different tissues. By 2005, proteomics was being used for protein quantitation, typically based on "proteotypic" peptides which act as surrogates for the parent proteins. Biomarker discovery is usually done by non-targeted "shotgun" proteomics, using relative quantitation methods to determine protein expression changes that correlate with disease (output given as "up-or-down regulation" or "fold-increases"). MS-based techniques can also perform "absolute" quantitation which is required for clinical applications (output given as protein concentrations). Here we describe the differences between these methods, factors that affect the precision and accuracy of the results, and some examples of recent studies using MS-based proteomics to verify cancer-related biomarkers. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

From the street to the laboratory: analytical profiles of methoxetamine, 3-methoxyeticyclidine and 3-methoxyphencyclidine and their determination in three biological matrices.

PubMed

De Paoli, Giorgia; Brandt, Simon D; Wallach, Jason; Archer, Roland P; Pounder, Derrick J

2013-06-01

Three psychoactive arylcyclohexylamines, advertised as "research chemicals," were obtained from an online retailer and characterized by gas chromatography ion trap electron and chemical ionization mass spectrometry, nuclear magnetic resonance spectroscopy and diode array detection. The three phencyclidines were identified as 2-(ethylamino)-2-(3-methoxyphenyl)cyclohexanone (methoxetamine), N-ethyl-1-(3-methoxyphenyl)cyclohexanamine and 1-[1-(3-methoxyphenyl)cyclohexyl]piperidine. A qualitative/quantitative method of analysis was developed and validated using liquid chromatography (HPLC) electrospray tandem mass spectrometry and ultraviolet (UV) detection for the determination of these compounds in blood, urine and vitreous humor. HPLC-UV proved to be a robust, accurate and precise method for the qualitative and quantitative analysis of these substances in biological fluids (0.16-5.0 mg/L), whereas the mass spectrometer was useful as a confirmatory tool.

Determination of volatile monophenols in beer using acetylation and headspace solid-phase microextraction in combination with gas chromatography and mass spectrometry.

PubMed

Sterckx, Femke L; Saison, Daan; Delvaux, Freddy R

2010-08-31

Monophenols are widely spread compounds contributing to the flavour of many foods and beverages. They are most likely present in beer, but so far, little is known about their influence on beer flavour. To quantify these monophenols in beer, we optimised a headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry. To improve their isolation from the beer matrix and their chromatographic properties, the monophenols were acetylated using acetic anhydride and KHCO(3) as derivatising agent and base catalyst, respectively. Derivatisation conditions were optimised with attention for the pH of the reaction medium. Additionally, different parameters affecting extraction efficiency were optimised, including fibre coating, extraction time and temperature and salt addition. Afterwards, we calibrated and validated the method successfully and applied it for the analysis of monophenols in beer samples. 2010 Elsevier B.V. All rights reserved.

High-throughput and direct measurement of androgen levels using turbulent flow chromatography liquid chromatography-triple quadrupole mass spectrometry (TFC-LC-TQMS) to discover chemicals that modulate dihydrotestosterone production in human prostate cancer cells.

PubMed

Kang, Kyungsu; Peng, Lei; Jung, Yu-Jin; Kim, Joo Yeon; Lee, Eun Ha; Lee, Hee Ju; Kim, Sang Min; Sung, Sang Hyun; Pan, Cheol-Ho; Choi, Yongsoo

2018-02-01

To develop a high-throughput screening system to measure the conversion of testosterone to dihydrotestosterone (DHT) in cultured human prostate cancer cells using turbulent flow chromatography liquid chromatography-triple quadrupole mass spectrometry (TFC-LC-TQMS). After optimizing the cell reaction system, this method demonstrated a screening capability of 103 samples, including 78 single compounds and 25 extracts, in less than 12 h without manual sample preparation. Consequently, fucoxanthin, phenethyl caffeate, and Curcuma longa L. extract were validated as bioactive chemicals that inhibited DHT production in cultured DU145 cells. In addition, naringenin boosted DHT production in DU145 cells. The method can facilitate the discovery of bioactive chemicals that modulate the DHT production, and four phytochemicals are potential candidates of nutraceuticals to adjust DHT levels in male hormonal dysfunction.

Rapid screening and identification of multi-class substances of very high concern in textiles using liquid chromatography-hybrid linear ion trap orbitrap mass spectrometry.

PubMed

Zhang, Li; Luo, Xin; Niu, Zengyuan; Ye, Xiwen; Tang, Zhixu; Yao, Peng

2015-03-20

A new analytical method was established and validated for the analysis of 19 substances of very high concern (SVHCs) in textiles, including phthalic acid esters (PAEs), organotins (OTs), perfluorochemicals (PFCs) and flame retardants (FRs). After ultrasonic extraction in methanol, the textile samples were analyzed by high performance liquid chromatography-hybrid linear ion trap Orbitrap high resolution mass spectrometry (HPLC-LTQ/Orbitrap). The values of LOQ were in the range of 2-200mg/kg. Recoveries at two levels (at the LOQ and at half the limit of regulation) ranged from 68% to 120%, and the repeatability was lower than 13%. This method was successfully applied to the screening of SVHCs in commercial textile samples and is useful for the fast screening of various SVHCs. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological Matrix Effects in Quantitative Tandem Mass Spectrometry-Based Analytical Methods: Advancing Biomonitoring

PubMed Central

Panuwet, Parinya; Hunter, Ronald E.; D’Souza, Priya E.; Chen, Xianyu; Radford, Samantha A.; Cohen, Jordan R.; Marder, M. Elizabeth; Kartavenka, Kostya; Ryan, P. Barry; Barr, Dana Boyd

2015-01-01

The ability to quantify levels of target analytes in biological samples accurately and precisely, in biomonitoring, involves the use of highly sensitive and selective instrumentation such as tandem mass spectrometers and a thorough understanding of highly variable matrix effects. Typically, matrix effects are caused by co-eluting matrix components that alter the ionization of target analytes as well as the chromatographic response of target analytes, leading to reduced or increased sensitivity of the analysis. Thus, before the desired accuracy and precision standards of laboratory data are achieved, these effects must be characterized and controlled. Here we present our review and observations of matrix effects encountered during the validation and implementation of tandem mass spectrometry-based analytical methods. We also provide systematic, comprehensive laboratory strategies needed to control challenges posed by matrix effects in order to ensure delivery of the most accurate data for biomonitoring studies assessing exposure to environmental toxicants. PMID:25562585

Validation of a multi-residue method for the determination of several antibiotic groups in honey by LC-MS/MS.

PubMed

Bohm, Detlef A; Stachel, Carolin S; Gowik, Petra

2012-07-01

The presented multi-method was developed for the confirmation of 37 antibiotic substances from the six antibiotic groups: macrolides, lincosamides, quinolones, tetracyclines, pleuromutilines and diamino-pyrimidine derivatives. All substances were analysed simultaneously in a single analytical run with the same procedure, including an extraction with buffer, a clean-up by solid-phase extraction, and the measurement by liquid chromatography tandem mass spectrometry in ESI+ mode. The method was validated on the basis of an in-house validation concept with factorial design by combination of seven factors to check the robustness in a concentration range of 5-50 μg kg(-1). The honeys used were of different types with regard to colour and origin. The values calculated for the validation parameters-decision limit CCα (range, 7.5-12.9 μg kg(-1)), detection capability CCβ (range, 9.4-19.9 μg kg(-1)), within-laboratory reproducibility RSD(wR) (<20% except for tulathromycin with 23.5% and tylvalosin with 21.4 %), repeatability RSD(r) (<20% except for tylvalosin with 21.1%), and recovery (range, 92-106%)-were acceptable and in agreement with the criteria of Commission Decision 2002/657/EC. The validation results showed that the method was applicable for the residue analysis of antibiotics in honey to substances with and without recommended concentrations, although some changes had been tested during validation to determine the robustness of the method.

Microfluidic direct injection method for analysis of urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) using molecularly imprinted polymers coupled on-line with LC-MS/MS.

PubMed

Shah, Kumar A; Peoples, Michael C; Halquist, Matthew S; Rutan, Sarah C; Karnes, H Thomas

2011-01-25

The work described in this paper involves development of a high-throughput on-line microfluidic sample extraction method using capillary micro-columns packed with MIP beads coupled with tandem mass spectrometry for the analysis of urinary NNAL. The method was optimized and matrix effects were evaluated and resolved. The method enabled low sample volume (200 μL) and rapid analysis of urinary NNAL by direct injection onto the microfluidic column packed with molecularly imprinted beads engineered to NNAL. The method was validated according to the FDA bioanalytical method validation guidance. The dynamic range extended from 20.0 to 2500.0 pg/mL with a percent relative error of ±5.9% and a run time of 7.00 min. The lower limit of quantitation was 20.0 pg/mL. The method was used for the analysis of NNAL and NNAL-Gluc concentrations in smokers' urine. Copyright © 2010 Elsevier B.V. All rights reserved.

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. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Rapid determination of eight bioactive alkaloids in Portulaca oleracea L. by the optimal microwave extraction combined with positive-negative conversion multiple reaction monitor (+/-MRM) technology.

PubMed

Liang, Xiao; Tian, Jinlong; Li, Lingzhi; Gao, Jun; Zhang, Qingyi; Gao, Pinyi; Song, Shaojiang

2014-03-01

A rapid and reliable microwave extraction and the triple quadrupole-linear ion trap mass spectrometry method was developed and validated for the determination of eight alkaloids in Portulaca oleracea L. The optimal microwave extraction (MWE) condition was performed at 60 °C for 12 min with ethanol-water (70:30, v/v) as the extracting solvent, and the solvent to solid ratio was 30:1. The alkaloids were first detected simultaneously by electrospray ionization tandem mass spectrometry under positive-negative conversion multiple reaction monitor ((+/-)MRM) technique. With investigating three different columns, samples were separated in only 8 min on a Waters ACQUITY UPLC HSS T3 (50 × 2.1 mm(2), 1.8 μm) column using acetonitrile and formic acid-water solution as a mobile phase with a flow rate at 0.2 mL/min. All calibration curves showed good linearity (r>0.999) within the test ranges. The method developed was validated with acceptable sensitivity, intra- and inter-day precision, reproducibility, and extraction recoveries. It was successfully applied to the determination of eight alkaloids in Portulaca oleracea L. from different sources and different harvest periods. The method also provide a reference for extraction and determination of alkaloids in other complex systems. © 2013 Elsevier B.V. All rights reserved.

Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods

PubMed Central

Lv, Surong; Niu, Yumin; Zhang, Jing; Shao, Bing; Du, Zhenxia

2017-01-01

Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate. PMID:28281659

Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method Coupled with Dispersive Solid-Phase Extraction for Simultaneous Quantification of Eight Paralytic Shellfish Poisoning Toxins in Shellfish.

PubMed

Yang, Xianli; Zhou, Lei; Tan, Yanglan; Shi, Xizhi; Zhao, Zhiyong; Nie, Dongxia; Zhou, Changyan; Liu, Hong

2017-06-29

In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of eight paralytic shellfish poisoning (PSP) toxins, including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins (GTX1-4) and the N -sulfo carbamoyl toxins C1 and C2, in sea shellfish. The samples were extracted by acetonitrile/water (80:20, v / v ) with 0.1% formic and purified by dispersive solid-phase extraction (dSPE) with C18 silica and acidic alumina. Qualitative and quantitative detection for the target toxins were conducted under the multiple reaction monitoring (MRM) mode by using the positive electrospray ionization (ESI) mode after chromatographic separation on a TSK-gel Amide-80 HILIC column with water and acetonitrile. Matrix-matched calibration was used to compensate for matrix effects. The established method was further validated by determining the linearity ( R ² ≥ 0.9900), average recovery (81.52-116.50%), sensitivity (limits of detection (LODs): 0.33-5.52 μg·kg -1 ; limits of quantitation (LOQs): 1.32-11.29 μg·kg -1 ) and precision (relative standard deviation (RSD) ≤ 19.10%). The application of this proposed approach to thirty shellfish samples proved its desirable performance and sufficient capability for simultaneous determination of multiclass PSP toxins in sea foods.

Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods

NASA Astrophysics Data System (ADS)

Lv, Surong; Niu, Yumin; Zhang, Jing; Shao, Bing; Du, Zhenxia

2017-03-01

Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate.

Rapid, simultaneous and nanomolar determination of pyroglutamic acid and cis-/trans-urocanic acid in human stratum corneum by hydrophilic interaction liquid chromatography (HILIC)-electrospray ionization tandem mass spectrometry.

PubMed

Joo, Kyung-Mi; Han, Ji Yeon; Son, Eui Dong; Nam, Gae-Won; Chung, Han Young; Jeong, Hye-Jin; Cho, Jun-Cheol; Lim, Kyung-Min

2012-05-15

A rapid, sensitive and specific hydrophilic interaction liquid chromatography coupled to tandem mass spectrometric (HILIC-MS/MS) method for the simultaneous determination of pyroglutamic acid, cis- and trans-urocanic acid in human skin stratum corneum (SC) were developed and validated. This method was carried out without derivatization or addition of ion-pair additives in mobile phase. The analytes were extracted by PBS buffer solution and analyzed using an electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an AQUITY UPLC amide column using gradient elution with the mobile phase of water and acetonitrile. The standard curves were linear over the concentration range of 1.0-250 ng/mL with a correlation coefficient higher than 0.999 with an LLOQ of 0.5 ng/mL. The lower limits of detection (LLOD) of these analytes were lower than 0.2 ng/mL. The intra- and inter-day precisions were measured to be below 7.7% and accuracies were within the range of 94.3-102.6%. The validated method was successfully applied to determine the level of pyroglutamic acid and cis-/trans-urocanic acid in the SC samples from forearm and forehead region of 19 human volunteers. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous determination of antidementia drugs in human plasma for therapeutic drug monitoring.

PubMed

Noetzli, Muriel; Choong, Eva; Ansermot, Nicolas; Eap, Chin B

2011-04-01

A simple liquid chromatography mass spectrometry method was developed and validated for the simultaneous determination of antidementia drugs, including donepezil, galantamine, rivastigmine and its major metabolite, NAP 226-90, and memantine. A solid phase extraction procedure with a mixed-mode sorbent was used to isolate the drugs from 0.5 mL human plasma. Reverse phase chromatographic separation of the compounds was obtained with a gradient elution of an ammonium acetate buffer at pH 9.3 and acetonitrile and the analytes were detected by mass spectrometry in the single ion monitoring mode. The method was validated according to the recommendations of the Food and Drug Administration, including assessment of trueness (-8.0% to +10.7%), imprecision (repeatability: 1.1-4.9%, intermediate imprecision: 2.1-8.5%), selectivity and matrix effects variability (less than 6%) as well as short- and long-term stability in plasma. The calibration ranges were from 1 ng/mL to 300 ng/mL (rivastigmine and memantine) and 2 ng/mL to 300 ng/mL (donepezil, galantamine, and NAP 226-90). The method was successfully applied to patients' samples and might contribute to evaluate whether a therapeutic drug monitoring-guided dose adjustment of antidementia drugs could contribute to minimize the risk of adverse reactions and to increase the probability of efficient therapeutic response.

Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods.

PubMed

Lv, Surong; Niu, Yumin; Zhang, Jing; Shao, Bing; Du, Zhenxia

2017-03-10

Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate.

Enantioselective column coupled electrophoresis employing large bore capillaries hyphenated with tandem mass spectrometry for ultra-trace determination of chiral compounds in complex real samples.

PubMed

Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Havránek, Emil; Mikuš, Peter

2015-12-01

A new multidimensional analytical approach for the ultra-trace determination of target chiral compounds in unpretreated complex real samples was developed in this work. The proposed analytical system provided high orthogonality due to on-line combination of three different methods (separation mechanisms), i.e. (1) isotachophoresis (ITP), (2) chiral capillary zone electrophoresis (chiral CZE), and (3) triple quadrupole mass spectrometry (QqQ MS). The ITP step, performed in a large bore capillary (800 μm), was utilized for the effective sample pretreatment (preconcentration and matrix clean-up) in a large injection volume (1-10 μL) enabling to obtain as low as ca. 80 pg/mL limits of detection for the target enantiomers in urine matrices. In the chiral CZE step, the different chiral selectors (neutral, ionizable, and permanently charged cyclodextrins) and buffer systems were tested in terms of enantioselectivity and influence on the MS detection response. The performance parameters of the optimized ITP - chiral CZE-QqQ MS method were evaluated according to the FDA guidance for bioanalytical method validation. Successful validation and application (enantioselective monitoring of renally eliminated pheniramine and its metabolite in human urine) highlighted great potential of this chiral approach in advanced enantioselective biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lipidomics by ultrahigh performance liquid chromatography-high resolution mass spectrometry and its application to complex biological samples

PubMed Central

Triebl, Alexander; Trötzmüller, Martin; Hartler, Jürgen; Stojakovic, Tatjana; Köfeler, Harald C

2018-01-01

An improved approach for selective and sensitive identification and quantitation of lipid molecular species using reversed phase chromatography coupled to high resolution mass spectrometry was developed. The method is applicable to a wide variety of biological matrices using a simple liquid-liquid extraction procedure. Together, this approach combines three selectivity criteria: Reversed phase chromatography separates lipids according to their acyl chain length and degree of unsaturation and is capable of resolving positional isomers of lysophospholipids, as well as structural isomers of diacyl phospholipids and glycerolipids. Orbitrap mass spectrometry delivers the elemental composition of both positive and negative ions with high mass accuracy. Finally, automatically generated tandem mass spectra provide structural insight into numerous glycerolipids, phospholipids, and sphingolipids within a single run. Method validation resulted in a linearity range of more than four orders of magnitude, good values for accuracy and precision at biologically relevant concentration levels, and limits of quantitation of a few femtomoles on column. Hundreds of lipid molecular species were detected and quantified in three different biological matrices, which cover well the wide variety and complexity of various model organisms in lipidomic research. Together with a reliable software package, this method is a prime choice for global lipidomic analysis of even the most complex biological samples. PMID:28415015

Simultaneous quantitation of six major quassinoids in Tongkat Ali dietary supplements by liquid chromatography with tandem mass spectrometry.

PubMed

Han, Young Min; Jang, Moonhee; Kim, In Sook; Kim, Seung Hyun; Yoo, Hye Hyun

2015-07-01

Tongkat Ali (Eurycoma longifolia) is one of the most popular traditional herbs in Southeast Asia and generally consumed as forms of dietary supplements, tea, or drink additives for coffee or energy beverages. In this study, the liquid chromatography with tandem mass spectrometry method for the simultaneous quantitation of six major quassinoids of Tongkat Ali (eurycomanone, 13,21-dihydroeurycomanone, 13α(21)-epoxyeurycomanone, 14,15β-dihydroxyklaineanone, eurycomalactone, and longilactone) was developed and validated. Using the developed method, the content of the six quassinoids was measured in Tongkat Ali containing dietary supplement tablets or capsules, and the resulting data were used to confirm the presence of Tongkat Ali in those products. Among the six quassinoids, eurycomanone was the most abundant quassinoid in all samples tested. The developed method would be useful for the quality assessment of Tongkat Ali containing dietary supplements. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of the extracts of Isatis tinctoria by new analytical approaches of HPLC, MS and NMR.

PubMed

Zhou, Jue; Qu, Fan

2011-01-01

The methods of extraction, separation and analysis of alkaloids and indole glucosinolates (GLs) ofIsatis tinctoria were reviewed. Different analytical approaches such as High-pressure Liquid Chromatography (HPLC), Liquid Chromatography with Electrospray Ionization Mass Spectrometry (LC/ESI/MS), Electrospray Ionization Time-Of-Flight Mass Spectrometry (ESI-TOF-MS), and Nuclear Magnetic Resonance (NMR) were used to validate and identity of these constituents. These methods provide rapid separation, identification and quantitative measurements of alkaloids and GLs of Isatis tinctoria. By connection with different detectors to HPLC such as PDA, ELSD, ESI- and APCI-MS in positive and negative ion modes, complicated compounds could be detected with at least two independent detection modes. The molecular formula can be derived in a second step of ESI-TOF-MS data. But for some constituents, UV and MS cannot provide sufficient structure identification. After peak purification, NMR by semi-preparative HPLC can be used as a complementary method.

Ultra trace determination of 31 pesticides in water samples by direct injection-rapid resolution liquid chromatography-electrospray tandem mass spectrometry.

PubMed

Díaz, Laura; Llorca-Pórcel, Julio; Valor, Ignacio

2008-08-22

A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for the detection of pesticides in tap and treated wastewater was developed and validated according to the ISO/IEC 17025:1999. Key features of this method include direct injection of 100 microL of sample, an 11 min separation by means of a rapid resolution liquid chromatography system with a 4.6 mm x 50 mm, 1.8 microm particle size reverse phase column and detection by electrospray ionization (ESI) MS-MS. The limits of detection were below 15 ng L(-1) and correlation coefficients for the calibration curves in the range of 30-2000 ng L(-1) were higher than 0.99. Precision was always below 20% and accuracy was confirmed by external evaluation. The main advantages of this method are direct injection of sample without preparative procedures and low limits of detection that fulfill the requirements established by the current European regulations governing pesticide detection.

Enantiomeric determination of DOPA in dietary supplements containing Mucuna pruriens by liquid chromatography/mass spectrometry.

PubMed

Hasegawa, Takashi; Takahashi, Kazunaga; Fukiwake, Tomohide; Saijo, Masaaki; Motoki, Yuji

2013-01-01

We developed a simple and rapid liquid chromatography/mass spectrometry (LC/MS) method for the enantiomeric determination of DOPA in dietary supplements containing Mucuna pruriens. L- and D-DOPA were ultrasonically extracted with 1% formic acid aqueous solution. The isolated extracts were analyzed by LC/MS using a Crownpak CR (-) column at 30℃. The mass spectrometer was operated in the positive mode of electrospray ionization, and the mobile phase was aqueous formic acid (pH 2.0). L-DOPA-ring-d3 was used as an internal standard. The method was validated for a dietary supplement spiked with L- and D-DOPA at 50 and 500 μg/g, respectively, and the recoveries of the DOPA enantiomers were between 97.5% and 101.3%. Relative standard deviation values of repeatability and intermediate precision were less than 7%. The method was applied to 14 dietary supplements. L-DOPA was detected in these supplements in the range of 0.88-12.8 mg/unit. D-DOPA was not detected.

Analysis of potential migrants from plastic materials in milk by liquid chromatography-mass spectrometry with liquid-liquid extraction and low-temperature purification.

PubMed

Bodai, Zsolt; Szabó, Bálint Sámuel; Novák, Márton; Hámori, Susanne; Nyiri, Zoltán; Rikker, Tamás; Eke, Zsuzsanna

2014-10-15

A simple and fast analytical method was developed for the determination of six UV stabilizers (Cyasorb UV-1164, Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, and Tinuvin 1577) and five antioxidants (Irgafos 168, Irganox 1010, Irganox 3114, Irganox 3790, and Irganox 565) in milk. For sample preparation liquid-liquid extraction with low-temperature purification combined with centrifugation was used to remove fats, proteins, and sugars. After the cleanup step, the sample was analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). External standard and matrix calibrations were tested. External calibration proved to be acceptable for Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, Irganox 3114, and Irganox 3790. The method was successfully validated with matrix calibration for all compounds. Method detection limits were between 0.25 and 10 μg/kg. Accuracies ranged from 93 to 109%, and intraday precisions were <13%.

Derivatization coupled to headspace programmed-temperature vaporizer gas chromatography with mass spectrometry for the determination of amino acids: Application to urine samples.

PubMed

González Paredes, Rosa María; García Pinto, Carmelo; Pérez Pavón, José Luis; Moreno Cordero, Bernardo

2016-09-01

A new method based on headspace programmed-temperature vaporizer gas chromatography with mass spectrometry has been developed and validated for the determination of amino acids (alanine, sarcosine, ethylglycine, valine, leucine, and proline) in human urine samples. Derivatization with ethyl chloroformate was employed successfully to determine the amino acids. The derivatization reaction conditions as well as the variables of the headspace sampling were optimized. The existence of a matrix effect was checked and the analytical characteristics of the method were determined. The limits of detection were 0.15-2.89 mg/L, and the limits of quantification were 0.46-8.67 mg/L. The instrumental repeatability was 1.6-11.5%. The quantification of the amino acids in six urine samples from healthy subjects was performed with the method developed with the one-point standard additions protocol, with norleucine as the internal standard. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-throughput method for the determination of residues of β-lactam antibiotics in bovine milk by LC-MS/MS.

PubMed

Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

2015-01-01

This study describes the development and validation procedures for scope extension of a method for the determination of β-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCβ), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin - CLX and cefapirin - CFAP.

Development and validation of a LC-MS/MS method for the determination of clebopride and its application to a pharmacokinetics study in healthy Chinese volunteers.

PubMed

Tan, Zhirong; Ouyang, Dongsheng; Chen, Yao; Zhou, Gan; Cao, Shan; Wang, Yicheng; Peng, Xiujuan; Zhou, Honghao

2010-08-01

A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) method has been developed and validated for the identification and quantification of clebopride in human plasma using itopride as an internal standard. The method involves a simple liquid-liquid extraction. The analytes were separated by isocratic gradient elution on a CAPCELL MG-III C(18) (5 microm, 150 mm x 2.1 mm i.d.) column and analyzed in multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI) interface using the respective [M+H](+) ions, m/z 373.9-->m/z184.0 for clebopride, m/z 359.9-->m/z71.5 for itopride. The method was validated over the concentration range of 69.530-4450.0 pg/ml for clebopride. Within- and between-batch precision (RSD%) was all within 6.83% and accuracy ranged from -8.16 to 1.88%. The LLOQ was 69.530 pg/ml. The extraction recovery was on an average 77% for clebopride. The validated method was used to study the pharmacokinetics profile of clebopride in human plasma after oral administration of clebopride. Copyright 2010. Published by Elsevier B.V.

Liquid chromatography tandem-mass spectrometry (LC-MS/MS) and dried blood spot sampling applied to pharmacokinetics studies in animals: Correlation of classic and block design.

PubMed

Baldo, Matías N; Angeli, Emmanuel; Gareis, Natalia C; Hunzicker, Gabriel A; Murguía, Marcelo C; Ortega, Hugo H; Hein, Gustavo J

2018-04-01

A relative bioavailability study (RBA) of two phenytoin (PHT) formulations was conducted in rabbits, in order to compare the results obtained from different matrices (plasma and blood from dried blood spot (DBS) sampling) and different experimental designs (classic and block). The method was developed by liquid chromatography tandem-mass spectrometry (LC-MS/MS) in plasma and blood samples. The different sample preparation techniques, plasma protein precipitation and DBS, were validated according to international requirements. The analytical method was validated with ranges 0.20-50.80 and 0.12-20.32 µg ml -1 , r > 0.999 for plasma and blood, respectively. Accuracy and precision were within acceptance criteria for bioanalytical assay validation (< 15 for bias and CV% and < 20 for limit of quantification (LOQ)). PHT showed long-term stability, both for plasma and blood, and under refrigerated and room temperature conditions. Haematocrit values were measured during the validation process and RBA study. Finally, the pharmacokinetic parameters (C max , T max and AUC 0-t ) obtained from the RBA study were tested. Results were highly comparable for matrices and experimental designs. A matrix correlation higher than 0.975 and a ratio of (PHT blood) = 1.158 (PHT plasma) were obtained. The results obtained herein show that the use of classic experimental design and DBS sampling for animal pharmacokinetic studies should be encouraged as they could help to prevent the use of a large number of animals and also animal euthanasia. Finally, the combination of DBS sampling with LC-MS/MS technology showed to be an excellent tool not only for therapeutic drug monitoring but also for RBA studies.

Validation of the Mass-Extraction-Window for Quantitative Methods Using Liquid Chromatography High Resolution Mass Spectrometry.

PubMed

Glauser, Gaétan; Grund, Baptiste; Gassner, Anne-Laure; Menin, Laure; Henry, Hugues; Bromirski, Maciej; Schütz, Frédéric; McMullen, Justin; Rochat, Bertrand

2016-03-15

A paradigm shift is underway in the field of quantitative liquid chromatography-mass spectrometry (LC-MS) analysis thanks to the arrival of recent high-resolution mass spectrometers (HRMS). The capability of HRMS to perform sensitive and reliable quantifications of a large variety of analytes in HR-full scan mode is showing that it is now realistic to perform quantitative and qualitative analysis with the same instrument. Moreover, HR-full scan acquisition offers a global view of sample extracts and allows retrospective investigations as virtually all ionized compounds are detected with a high sensitivity. In time, the versatility of HRMS together with the increasing need for relative quantification of hundreds of endogenous metabolites should promote a shift from triple-quadrupole MS to HRMS. However, a current "pitfall" in quantitative LC-HRMS analysis is the lack of HRMS-specific guidance for validated quantitative analyses. Indeed, false positive and false negative HRMS detections are rare, albeit possible, if inadequate parameters are used. Here, we investigated two key parameters for the validation of LC-HRMS quantitative analyses: the mass accuracy (MA) and the mass-extraction-window (MEW) that is used to construct the extracted-ion-chromatograms. We propose MA-parameters, graphs, and equations to calculate rational MEW width for the validation of quantitative LC-HRMS methods. MA measurements were performed on four different LC-HRMS platforms. Experimentally determined MEW values ranged between 5.6 and 16.5 ppm and depended on the HRMS platform, its working environment, the calibration procedure, and the analyte considered. The proposed procedure provides a fit-for-purpose MEW determination and prevents false detections.

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. Copyright © 2015 John Wiley & Sons, Ltd.

Development and validation of a UPLC-MS/MS method for quantitation of droxidopa in human plasma: Application to a pharmacokinetic study.

PubMed

Wang, Haidong; Yang, Guangsheng; Zhou, Jinyu; Pei, Jiang; Zhang, Qiangfeng; Song, Xingfa; Sun, Zengxian

2016-08-01

In this study, a simple and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for quantitation of droxidopa in human plasma for the first time. A simple plasma protein precipitation method using methanol containing 3% formic acid was selected, and the separation was achieved by an Acquity UPLC™ BEH Amide column (2.1mm×50mm, 1.7μm) with a gradient elution using acetonitrile, ammonium formate buffer and formic acid as mobile phase. The detection of droxidopa and benserazide (internal standard, IS) was performed using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The precursor-to-product ion transitions m/z 214.2→m/z 152.0 for droxidopa, and m/z 258.1→m/z 139.1 for IS were used for quantification. A lower limit of quantification of 5.00ng/mL was achieved and the linear curve range was 5.00-4000ng/mL using a weighted (1/x(2)) linear regression model. Intra-assay and inter-assay precision was less than 10.2%, and the accuracy ranged from 0.1% to 2.1%. Stability, recovery and matrix effects were within the acceptance criteria recommended by the regulatory bioanalytical guidelines. The method was successfully applied to a pharmacokinetic study of droxidopa in healthy Chinese volunteers. Copyright © 2016. Published by Elsevier B.V.

Development and validation of a liquid chromatography-tandem mass spectrometry method for the separation of conjugated and unconjugated 17alpha- and 17beta-boldenone in urine sample.

PubMed

Gasparini, Mara; Assini, Walter; Bozzoni, Eros; Tognoli, Nadia; Dusi, Guglielmo

2007-03-14

Natural occurrence or illegal treatment of boldenone (BOLD) presence in cattle urine is under debate within the European Union. Separation of conjugated and unconjugated forms of 17alpha-boldenone (alpha-BOLD) and 17beta-boldenone (beta-BOLD) and presence of related molecules as androsta-1,4-diene-3,17-dione (ADD) appear critical points for the decision of an illegal use. The aim of this study is a new analytical approach of BOLD and ADD confirmation in cattle urine. The separation between conjugated and unconjugated forms of BOLD was obtained by a preliminary urine liquid-liquid extraction step with ethyl acetate. In this step the organic phase extracts only unconjugated BOLD and ADD, while BOLD in conjugated form remain in urine phase. Afterwards the urine phase, contains conjugated BOLD, was subjected to an enzymatic deconjugation. Solid-phase extraction (OASIS-HLB Waters) was used for the purification and concentration of analytes in organic and urine phases and liquid chromatography ion electrospray tandem mass spectrometry (LC-MS-MS) was applied for the confirmation of BOLD and ADD, using deuterium-labelled 17beta-boldenone (BOLD-d3) as internal standard. The method was validated as a quantitative confirmatory method according to the Commission Decision 2002/657/CE. The results obtained demonstrate that the developed method show very high specificity, precision, trueness and ruggedness. Decision limits (CCalpha) smaller than 0.5 ng mL(-1) were obtained for each analyte.

Stir bar sorptive extraction and liquid chromatography-tandem mass spectrometry determination of polar and non-polar emerging and priority pollutants in environmental waters.

PubMed

Aparicio, Irene; Martín, Julia; Santos, Juan Luis; Malvar, José Luis; Alonso, Esteban

2017-06-02

An analytical method based on stir bar sorptive extraction (SBSE) was developed and validated for the determination of environmental concern pollutants in environmental waters by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Target compounds include six water and oil repellents (perfluorinated compounds), four preservatives (butylated hydroxytoluene and three parabens), two plasticizers (bisphenol A and di(2-ethylhexyl)phthalate), seven surfactants (four linear alkylbenzene sulfonates, nonylphenol and two nonylphenol ethoxylates), a flame retardant (hexabromocyclododecane), four hormones, fourteen pharmaceutical compounds, an UV-filter (2-ethylhexyl 4-methoxycinnamate) and nine pesticides. To achieve the simultaneous extraction of polar and non-polar pollutants two stir bar coatings were tested, the classic polydimethylsiloxane (PDMS) coating and the novel ethylene glycol modified silicone (EG-silicone). The best extraction recoveries were obtained using EG-silicone coating. The effects of sample pH, volume and ionic strength and extraction time on extraction recoveries were evaluated. The analytical method was validated for surface water and tap water samples. The method quantification limits ranged from 7.0ngL -1 to 177ngL -1 . The inter-day precision, expressed as relative standard deviation, was lower than 20%. Accuracy, expressed as relative recovery values, was in the range from 61 to 130%. The method was applied for the determination of the 48 target compounds in surface and tap water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomonitoring of 21 endocrine disrupting chemicals in human hair samples using ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Rodríguez-Gómez, R; Martín, J; Zafra-Gómez, A; Alonso, E; Vílchez, J L; Navalón, A

2017-02-01

Rapid industrial growth has increased human exposure to a large variety of chemicals with adverse health effects. These industrial chemicals are usually present in the environment, foods, beverages, clothes and personal care products. Among these compounds, endocrine disrupting chemicals (EDCs) have raised concern over the last years. In the present work, the determination of 21 EDCs in human hair samples is proposed. An analytical method based on the digestion of the samples with a mixture of acetic acid/methanol (20:80, v/v) followed by a solid-liquid microextraction and analysis by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. The most influential parameters affecting the extraction method were optimized. The method was validated using matrix-matched calibration and recovery assays. Limits of detection ranged from 0.2 to 4 ng g -1 , limits of quantification from 0.5 to 12 ng g -1 , and inter- and intra-day variability was under 15% in all cases. Recovery rates for spiked samples ranged from 92.1 to 113.8%. The method was applied for the determination of the selected compounds in human hair. Samples were collected weekly from six randomly selected volunteers (three men and three women) over a three-month period. All the analyzed samples tested positive for at least one of the analyzed compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative analysis of drug distribution by ambient mass spectrometry imaging method with signal extinction normalization strategy and inkjet-printing technology.

PubMed

Luo, Zhigang; He, Jingjing; He, Jiuming; Huang, Lan; Song, Xiaowei; Li, Xin; Abliz, Zeper

2018-03-01

Quantitative mass spectrometry imaging (MSI) is a robust approach that provides both quantitative and spatial information for drug candidates' research. However, because of complicated signal suppression and interference, acquiring accurate quantitative information from MSI data remains a challenge, especially for whole-body tissue sample. Ambient MSI techniques using spray-based ionization appear to be ideal for pharmaceutical quantitative MSI analysis. However, it is more challenging, as it involves almost no sample preparation and is more susceptible to ion suppression/enhancement. Herein, based on our developed air flow-assisted desorption electrospray ionization (AFADESI)-MSI technology, an ambient quantitative MSI method was introduced by integrating inkjet-printing technology with normalization of the signal extinction coefficient (SEC) using the target compound itself. The method utilized a single calibration curve to quantify multiple tissue types. Basic blue 7 and an antitumor drug candidate (S-(+)-deoxytylophorinidine, CAT) were chosen to initially validate the feasibility and reliability of the quantitative MSI method. Rat tissue sections (heart, kidney, and brain) administered with CAT was then analyzed. The quantitative MSI analysis results were cross-validated by LC-MS/MS analysis data of the same tissues. The consistency suggests that the approach is able to fast obtain the quantitative MSI data without introducing interference into the in-situ environment of the tissue sample, and is potential to provide a high-throughput, economical and reliable approach for drug discovery and development. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of alkylphenols and bisphenol A in seawater samples by dispersive liquid-liquid microextraction and liquid chromatography tandem mass spectrometry for compliance with environmental quality standards (Directive 2008/105/EC).

PubMed

Salgueiro-González, N; Concha-Graña, E; Turnes-Carou, I; Muniategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

2012-02-03

A fast, simple, sensitive and green analytical chemistry method for the simultaneous determination of alkylphenols (4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, nonylphenol) and bisphenol A in seawater was developed and validated. The procedure was based on a dispersive liquid-liquid microextraction (DLLME) of a small volume of seawater sample (30 mL) using only 100 μL of 1-octanol, combined with liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode (LC-ESI-MS/MS). The matrix effect was studied and compensated using deuterated labelled standards as surrogate standards for the quantitation of target compounds. The analytical features of the proposed method were satisfactory: repeatability and intermediate precision were <10% and recoveries were around 84-104% for all compounds. Uncertainty assessment of measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) ranged between 0.005 and 0.03 μg L⁻¹, therefore the levels established in the Directive 2008/105/EC were achieved. The applicability of the proposed method was demonstrated analyzing seawater samples from different sites of A Coruña (Northwest of Spain). The analyses showed the presence of all compounds at levels between 0.035 (bisphenol A) and 0.14 μg L⁻¹ (nonylphenol). Copyright © 2011 Elsevier B.V. All rights reserved.

Extraction and Liquid Chromatography-Tandem Mass Spectrometry Detection of 3-Monochloropropanediol Esters and Glycidyl Esters in Infant Formula.

PubMed

Leigh, Jessica K; MacMahon, Shaun

2016-12-14

A method was developed for the extraction of fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD) and glycidol from infant formula, followed by quantitative analysis of the extracts using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These process-induced chemical contaminants are found in refined vegetable oils, and studies have shown that they are potentially carcinogenic and/or genotoxic, making their presence in edible oils (and processed foods containing these oils) a potential health risk. The extraction procedure involves a liquid-liquid extraction, where powdered infant formula is dissolved in water and extracted with ethyl acetate. Following shaking, centrifugation, and drying of the organic phase, the resulting fat extract is cleaned-up using solid-phase extraction and analyzed by LC-MS/MS. Method performance was confirmed by verifying the percent recovery of each 3-MCPD and glycidyl ester in a homemade powdered infant formula reference material. Average ester recoveries in the reference material ranged from 84.9 to 109.0% (0.6-9.5% RSD). The method was also validated by fortifying three varieties of commercial infant formulas with a 3-MCPD and glycidyl ester solution. Average recoveries of the esters across all concentrations and varieties of infant formula ranged from 88.7 to 107.5% (1.0-9.5% RSD). Based on the validation results, this method is suitable for producing 3-MCPD and glycidyl ester occurrence data in all commercially available varieties of infant formula.

An analytical method to screen for six thyreostatic drug residues in the thyroid gland and muscle tissues of food producing animals by liquid chromatography with ultraviolet absorption detection and liquid chromatography/mass spectrometry.

PubMed

Asea, Philip E; MacNeil, James D; Boison, Joe O

2006-01-01

A method was developed and validated to screen for residues of the thyreostatic drugs, tapazole (TAP), mercaptobenzimidazole (MBI), thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PrTU), and phenylthiouracil (PhTU) in bovine, equine, ovine, and porcine thyroid and muscle tissues at concentrations > or = 5 ng/g using 2-methoxy-mercaptobenzimidazole (MeMBI) and dimethylthiouracil (DMTU) as internal standards. In this method, the drugs were solvent extracted from thyroid and muscle tissue and cleaned up on an amino-propyl solid-phase extraction (SPE) cartridge. The unretained fraction containing TAP and MBI and the internal standard, MeMBI, was collected as Fraction 1. The retained fraction containing TU, MTU, PrTU, PhTU, and the internal standard, DMTU, was eluted with 3% acetic acid-isopropanol as Fraction 2. Fraction 1 was further cleaned up on an alumina B SPE cartridge and analyzed by gradient elution on a C18 high-performance liquid chromatography (HPLC) column with ultraviolet detection at wavelengths of 255 and 300 nm. Fraction 2 was taken to dryness, derivatized with 4-chloro-7-nitrobenzo-2-furazan at pH 8, and analyzed by gradient elution on a C18 LC column with mass spectrometry (MS) detection. Any "presumptive positive" test results were submitted for further analysis by LC/MS/MS. The validated method was applied to the analysis of over 300 thyroid tissue samples.

Validation and Clinical Evaluation of a Novel Method To Measure Miltefosine in Leishmaniasis Patients Using Dried Blood Spot Sample Collection

PubMed Central

Rosing, H.; Hillebrand, M. J. X.; Blesson, S.; Mengesha, B.; Diro, E.; Hailu, A.; Schellens, J. H. M.; Beijnen, J. H.

2016-01-01

To facilitate future pharmacokinetic studies of combination treatments against leishmaniasis in remote regions in which the disease is endemic, a simple cheap sampling method is required for miltefosine quantification. The aims of this study were to validate a liquid chromatography-tandem mass spectrometry method to quantify miltefosine in dried blood spot (DBS) samples and to validate its use with Ethiopian patients with visceral leishmaniasis (VL). Since hematocrit (Ht) levels are typically severely decreased in VL patients, returning to normal during treatment, the method was evaluated over a range of clinically relevant Ht values. Miltefosine was extracted from DBS samples using a simple method of pretreatment with methanol, resulting in >97% recovery. The method was validated over a calibration range of 10 to 2,000 ng/ml, and accuracy and precision were within ±11.2% and ≤7.0% (≤19.1% at the lower limit of quantification), respectively. The method was accurate and precise for blood spot volumes between 10 and 30 μl and for Ht levels of 20 to 35%, although a linear effect of Ht levels on miltefosine quantification was observed in the bioanalytical validation. DBS samples were stable for at least 162 days at 37°C. Clinical validation of the method using paired DBS and plasma samples from 16 VL patients showed a median observed DBS/plasma miltefosine concentration ratio of 0.99, with good correlation (Pearson's r = 0.946). Correcting for patient-specific Ht levels did not further improve the concordance between the sampling methods. This successfully validated method to quantify miltefosine in DBS samples was demonstrated to be a valid and practical alternative to venous blood sampling that can be applied in future miltefosine pharmacokinetic studies with leishmaniasis patients, without Ht correction. PMID:26787691

Supercritical fluid chromatography coupled with tandem mass spectrometry: A high-efficiency detection technique to quantify Taxane drugs in whole-blood samples.

PubMed

Jin, Chan; Guan, Jibin; Zhang, Dong; Li, Bing; Liu, Hongzhuo; He, Zhonggui

2017-10-01

We present a technique to rapid determine taxane in blood samples by supercritical fluid chromatography together with mass spectrometry. The aim of this study was to develop a supercritical fluid chromatography with mass spectrometry method for the analysis of paclitaxel, cabazitaxel, and docetaxel in whole-blood samples of rats. Liquid-dry matrix spot extraction was selected in sample preparation procedure. Supercritical fluid chromatography separation of paclitaxel, cabazitaxel, docetaxel, and glyburide (internal standard) was accomplished within 3 min by using the gradient mobile phase consisted of methanol as the compensation solvent and carbon dioxide at a flow rate of 1.0 mL/min. The method was validated regarding specificity, the lower limit of quantification, repeatability, and reproducibility of quantification, extraction recovery, and matrix effects. The lower limit of quantification was found to be 10 ng/mL since it exhibited acceptable precision and accuracy at the corresponding level. All interday accuracies and precisions were within the accepted criteria of ±15% of the nominal value and within ±20% at the lower limit of quantification, implying that the method was reliable and reproducible. In conclusion, this method is a promising tool to support and improve preclinical or clinical pharmacokinetic studies with the taxanes anticancer drugs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BASTet: Shareable and Reproducible Analysis and Visualization of Mass Spectrometry Imaging Data via OpenMSI.

PubMed

Rubel, Oliver; Bowen, Benjamin P

2018-01-01

Mass spectrometry imaging (MSI) is a transformative imaging method that supports the untargeted, quantitative measurement of the chemical composition and spatial heterogeneity of complex samples with broad applications in life sciences, bioenergy, and health. While MSI data can be routinely collected, its broad application is currently limited by the lack of easily accessible analysis methods that can process data of the size, volume, diversity, and complexity generated by MSI experiments. The development and application of cutting-edge analytical methods is a core driver in MSI research for new scientific discoveries, medical diagnostics, and commercial-innovation. However, the lack of means to share, apply, and reproduce analyses hinders the broad application, validation, and use of novel MSI analysis methods. To address this central challenge, we introduce the Berkeley Analysis and Storage Toolkit (BASTet), a novel framework for shareable and reproducible data analysis that supports standardized data and analysis interfaces, integrated data storage, data provenance, workflow management, and a broad set of integrated tools. Based on BASTet, we describe the extension of the OpenMSI mass spectrometry imaging science gateway to enable web-based sharing, reuse, analysis, and visualization of data analyses and derived data products. We demonstrate the application of BASTet and OpenMSI in practice to identify and compare characteristic substructures in the mouse brain based on their chemical composition measured via MSI.

Analysis of Thiodiglycol: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS777

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Koester, C

The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method for the analysis of thiodiglycol, the breakdown product of the sulfur mustard HD, in water by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), titled Method EPA MS777 (hereafter referred to as EPA CRL SOP MS777). This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to verifymore » the analytical procedures described in MS777 for analysis of thiodiglycol in aqueous samples. The gathered data from this study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of Method EPA MS777 can be determined.« less

Development and validation of an ultra-fast and sensitive microflow liquid chromatography-tandem mass spectrometry (MFLC-MS/MS) method for quantification of LSD and its metabolites in plasma and application to a controlled LSD administration study in humans.

PubMed

Steuer, Andrea E; Poetzsch, Michael; Stock, Lorena; Eisenbeiss, Lisa; Schmid, Yasmin; Liechti, Matthias E; Kraemer, Thomas

2017-05-01

Lysergic acid diethylamide (LSD) is a semi-synthetic hallucinogen that has gained popularity as a recreational drug and has been investigated as an adjunct to psychotherapy. Analysis of LSD represents a major challenge in forensic toxicology due to its instability, low drug concentrations, and short detection windows in biological samples. A new, fast, and sensitive microflow liquid chromatography (MFLC) tandem mass spectrometry method for the validated quantification of LSD, iso-LSD, 2-oxo 3-hydroxy-LSD (oxo-HO-LSD), and N-desmethyl-LSD (nor-LSD) was developed in plasma and applied to a controlled pharmacokinetic (PK) study in humans to test whether LSD metabolites would offer for longer detection windows. Five hundred microlitres of plasma were extracted by solid phase extraction. Analysis was performed on a Sciex Eksigent MFLC system coupled to a Sciex 5500 QTrap. The method was validated according to (inter)-national guidelines. MFLC allowed for separation of the mentioned analytes within 3 minutes and limits of quantification of 0.01 ng/mL. Validation criteria were fulfilled for all analytes. PK data could be calculated for LSD, iso-LSD, and oxo-HO-LSD in all participants. Additionally, hydroxy-LSD (HO-LSD) and HO-LSD glucuronide could be qualitatively detected and PK determined in 11 and 8 subjects, respectively. Nor-LSD was only sporadically detected. Elimination half-lives of iso-LSD (median 12 h) and LSD metabolites (median 9, 7.4, 12, and 11 h for oxo-HO-LSD, HO-LSD, HO-LSD-gluc, and nor-LSD, respectively) exceeded those of LSD (median 4.2 h). However, screening for metabolites to increase detection windows in plasma seems not to be constructive due to their very low concentrations. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Multiresidue method for detection of pesticides in beef meat using liquid chromatography coupled to mass spectrometry detection (LC-MS) after QuEChERS extraction.

PubMed

Oliveira, Fabiano Aurélio da Silva; Pereira, Elba Nathália Corrêa; Gobbi, Jennifer Mattedi; Soto-Blanco, Benito; Melo, Marília Martins

2018-01-01

Beef meat is an important food that can be contaminated by pesticides. This study aimed to optimize a multiresidue method for identification and quantification of pesticides in beef meat by liquid chromatography coupled to mass spectrometry detection (LC-MS). The extraction and clean-up procedures were adapted from the QuECHERS method. From the 188 analytes tested, the method was validated as qualitative method for 19 compounds and as quantitative method for 152 compounds. The results were satisfactory, yielding coefficients of variation of less than 20% and recoveries ranging from 70% to 120% and expanded uncertainty of less than 50%. The quantification limit was typically 10 µg kg -1 (but 25 µg kg -1 for 12 of the compounds) and the detection limit was 5.0 µg kg -1 . Thirty-two real samples of commercialized beef meat were analyzed without any residual pesticide being found. Thus, the results showed that the multiresidue method for detecting 171 pesticides, using adapted QuECHERS for extraction and LC-MS for detection, is suitable for analyzing beef meat.

A comparative pharmacokinetic study of three flavonoids and three anthraquinones in normal and gastrointestinal motility disorders rat plasma after the oral administration of Wei-Chang-Shu tablet using high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Ren, Yan; Zhao, Weiwei; Zhao, Juanjuan; Chen, Xiangming; Yu, Chen; Liu, Mengan

2017-11-01

A simple, fast and reliable high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification and pharmacokinetic study of three flavonoids (liquiritigenin, isoliquiritigenin and formononetin) and three anthraquinones (emodin, rhein and aloe-emodin), which are the bioactive ingredients of Wei-Chang-Shu tablet found in rat plasma. After extraction by liquid-liquid extraction with ethyl acetate, chromatographic separation was achieved on an Agilent Zorbax SB-C 18 column (4.6 × 150 mm, 5 μm) at a flow rate of 1 mL/min by gradient elution using 0.1% aqueous acetic acid and acetonitrile. The detection was performed using a triple quadrupole mass spectrometer equipped with electrospray ionization source in the negative ionization and selected reaction monitoring mode. Method validation was performed in terms of specificity, carryover, linearity (r > 0.99), intra-/inter-day precision (1.0-10.1%), accuracy (relative error, <7.6%), stability (0.6-13.2%), extract recovery (74.9-91.9%) and matrix effect (89.1-109%). The lower limits of quantification of the six analytes varied from 0.92 to 10.4 ng/mL. The validated method was successfully applied to compare the pharmacokinetic properties of Wei-Chang-Shu tablet in normal rats and in rats with gastrointestinal motility disorders. The results indicated that there were obvious differences in the pharmacokinetic behavior between normal and model rats. This study will be helpful in the clinical application of Wei-Chang-Shu tablet. Copyright © 2017 John Wiley & Sons, Ltd.

Determination of a highly selective mixed-affinity sigma receptor ligand, in rat plasma by ultra performance liquid chromatography mass spectrometry and its application to a pharmacokinetic study

PubMed Central

Jamalapuram, Seshulatha; Vuppala, Pradeep K.; Mesangeau, Christophe; McCurdy, Christopher R.; Avery, Bonnie A.

2014-01-01

A selective, rapid and sensitive ultra performance liquid chromatography mass spectrometry (UPLC/MS) method was developed and validated to quantitate a highly selective mixed-affinity sigma receptor ligand, CM156 (3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d] thiazole-2(3H)-thione), in rat plasma. CM156 and the internal standard (aripiprazole) were extracted from plasma samples by a single step liquid–liquid extraction using chloroform. The analysis was carried out on an ACQUITY UPLCTM BEH HILIC column (1.7 µm, 2.1 mm × 50 mm) with isocratic elution at flow rate of 0.2 mL/min using 10 mM ammonium formate in 0.1% formic acid and acetonitrile (10:90) as the mobile phase. The detection of the analyte was performed on a mass spectrometer operated in selected ion recording (SIR) mode with positive electrospray ionization (ESI). The validated analytical method resulted in a run time of 4 min and the retention times observed were 2.6 ± 0.1 and 2.1 ± 0.1 min for CM156 and the IS, respectively. The calibration curve exhibited excellent linearity over a concentration range of 5–4000 ng/mL with the lower limit of quantification of 5 ng/mL. The intra- and inter-day precision values were below 15% and accuracy ranged from −6.5% to 5.0%. The mean recovery of CM156 from plasma was 96.8%. The validated method was applied to a pilot intravenous pharmacokinetic study in rats. PMID:22406103

Highly sensitive measurement of whole blood chromium by inductively coupled plasma mass spectrometry.

PubMed

Cieslak, Wendy; Pap, Kathleen; Bunch, Dustin R; Reineks, Edmunds; Jackson, Raymond; Steinle, Roxanne; Wang, Sihe

2013-02-01

Chromium (Cr), a trace metal element, is implicated in diabetes and cardiovascular disease. A hypochromic state has been associated with poor blood glucose control and unfavorable lipid metabolism. Sensitive and accurate measurement of blood chromium is very important to assess the chromium nutritional status. However, interferents in biological matrices and contamination make the sensitive analysis challenging. The primary goal of this study was to develop a highly sensitive method for quantification of total Cr in whole blood by inductively coupled plasma mass spectrometry (ICP-MS) and to validate the reference interval in a local healthy population. This method was developed on an ICP-MS with a collision/reaction cell. Interference was minimized using both kinetic energy discrimination between the quadrupole and hexapole and a selective collision gas (helium). Reference interval was validated in whole blood samples (n=51) collected in trace element free EDTA tubes from healthy adults (12 males, 39 females), aged 19-64 years (38.8±12.6), after a minimum of 8 h fasting. Blood samples were aliquoted into cryogenic vials and stored at -70 °C until analysis. The assay linearity was 3.42 to 1446.59 nmol/L with an accuracy of 87.7 to 99.8%. The high sensitivity was achieved by minimization of interference through selective kinetic energy discrimination and selective collision using helium. The reference interval for total Cr using a non-parametric method was verified to be 3.92 to 7.48 nmol/L. This validated ICP-MS methodology is highly sensitive and selective for measuring total Cr in whole blood. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Published by Elsevier Inc. All rights reserved.

Blood monitoring of perfluorocarbon compounds (F-tert-butylcyclohexane, perfluoromethyldecalin and perfluorodecalin) by headspace-gas chromatography-tandem mass spectrometry.

PubMed

Giuliani, N; Saugy, M; Augsburger, M; Varlet, V

2015-11-01

A headspace-gas chromatography-tandem mass spectrometry (HS-GC-MS/MS) method for the trace measurement of perfluorocarbon compounds (PFCs) in blood was developed. Due to oxygen carrying capabilities of PFCs, application to doping and sports misuse is speculated. This study was therefore extended to perform validation methods for F-tert-butylcyclohexane (Oxycyte(®)), perfluoro(methyldecalin) (PFMD) and perfluorodecalin (PFD). The limit of detection of these compounds was established and found to be 1.2 µg/mL blood for F-tert-butylcyclohexane, 4.9 µg/mL blood for PFMD and 9.6 µg/mL blood for PFD. The limit of quantification was assumed to be 12 µg/mL blood (F-tert-butylcyclohexane), 48 µg/mL blood (PFMD) and 96 µg/mL blood (PFD). HS-GC-MS/MS technique allows detection from 1000 to 10,000 times lower than the estimated required dose to ensure a biological effect for the investigated PFCs. Thus, this technique could be used to identify a PFC misuse several hours, maybe days, after the injection or the sporting event. Clinical trials with those compounds are still required to evaluate the validation parameters with the calculated estimations. Copyright © 2015 Elsevier B.V. All rights reserved.

[Preparation and certification of mussel reference material for organochlorine pesticides and polychlorinated biphenyls using isotope dilution-high resolution mass spectrometry].

PubMed

Lu, Xianbo; Chen, Jiping; Wang, Shuqiu; Zou, Lili; Tian, Yuzeng; Ni, Yuwen; Su, Fan

2012-09-01

A method for the preparation and certification of the reference material of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in mussel tissue is described. The mussel tissue from Dalian Bay was frozen-dried, comminuted, sieved, homogenized, packaged, and sterilized by 60Co radiation sterilization in turn. The certified values for 18 OCPs and 16 PCBs were determined by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) using isotope dilution and internal standard quantitation techniques. The certified values were validated and given based on seven accredited laboratories, and these values are traceable to the SI (international system of units) through gravimetrically prepared standards of established purity and measurement intercomparisons. The certified values of PCBs and OCPs in mussel span 4 orders of magnitude with a relative uncertainty of about 10%. This material is a natural biological material with confirmed good homogeneity and stability, and it was approved as the grade "primary reference material" (GBW10069) in June 2012 in China. This reference material provided necessary quality control products for our country to implement the Stockholm Treaty on the monitoring of persistent organic pollutants (POPs). The material is intended to be used for the method validation and quality control in the determination of OCPs and PCBs in biota samples.

Detection of boldenone, its conjugates and androstadienedione, as well as five corticosteroids in bovine bile through a unique immunoaffinity column clean-up and two validated liquid chromatography-tandem mass spectrometry analyses.

PubMed

Chiesa, L; Nobile, M; Panseri, S; Sgoifo Rossi, C A; Pavlovic, R; Arioli, F

2014-12-10

The presence of β-boldenone II phase metabolites and prednisolone in urine samples, owing to endogenous or natural origin or illicit treatment, is under debate within the European Union. The detection of β-boldenone conjugates, α-boldenone conjugates at concentrations higher than 2 ng mL(-1) and prednisolone above the cut-off level of 5 ng mL(-1) in urine have been, until now, critical in deciding if illegal drug use has occurred. The use of urine sometimes is not entirely satisfactory, especially when the drug is administrated at low doses or when its metabolic conversion is very fast. This subsequently would hamper its detection in urine. The introduction of a new, advantageous matrix where the illicit treatment can be investigated would be highly appreciated. In this study, we have developed and validated a simple and unique immunoaffinity clean-up procedure, which was applied to bovine bile samples, followed by two different analytical liquid chromatography-electrospray-tandem mass spectrometry methods. The first method tests androstadienedione, α- and β-boldenone sulphate, glucuronate and related free forms, while the other method assays prednisolone, prednisone, dexamethasone, cortisone, and cortisol. The methods were validated according to European Commission Decision 2002/657/EC. The evaluated parameters were linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit and detection capability. The decision limits (CCα) were between 0.38 and 0.45 ng mL(-1) for anabolic steroids, and 0.13 and 0.15 ng mL(-1) as far as corticosteroids were concerned. Intra- and inter-day repeatability was below 15.8 and 19.9% for all analytes, respectively. The methods were applied to the analysis of some bile samples collected from untreated young bulls in order to investigate the presence of the studied steroids in this matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuerteltaub, K. W.; Bench, G.; Buchholz, B. A.

The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integratedmore » HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory instruments.4.) Provide high throughput 14C BioAMS analysis for collaborative and service clients.« less

Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turteltaub, K. W.; Bench, G.; Buchholz, B. A.

2016-04-08

The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integratedmore » HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory instruments.4.) Provide high throughput 14C BioAMS analysis for collaborative and service clients.« less

Simultaneous Determination of Ten Constituents in Chaiqin Qingning Capsule by High-performance Liquid Chromatography Coupled with Triple-quadrupole Mass Spectrometry

PubMed Central

Li, Ting Yu; Huo, Xiao Kui; Zheng, Lu; Wang, Chao; Cong, Hai Jian; Xiang, Ting; Zhang, Lin; Zhang, Bao Jing; Huang, Shan Shan; Wu, Bin; Li, Xin Yu

2017-01-01

Background: Chaiqin Qingning Capsule (CQQNC) was a prescription of Traditional Chinese Medicine with the effects of clearing away heat and removing toxin, harmonizing the exterior and interior, it was widely used in Asian, for example, China and Japan, different batches of the raws materials and different processing time may be the vital factor which raised a challenge to control the quality of the CQQNC. Experimental Methods: In this experiment, a high-performance liquid chromatography-mass spectrometry/MS (HPLC-MS/MS) method was developed to simultaneously determine ten bioactive components for the quality control of CQQNC. Chromatographic separation was achieved using an XBridge BEH C18 column (150 mm × 4.6 mm, 2.5 μm) with a mobile phase composed of 10 mm aqueous ammonium acetate and acetonitrile using a gradient elution in 20 min. This study was conducted by multiple reaction monitoring mode through electrospray ionization resource with a negative ionization mode. Results: The established method was validated with good performance of precision, accuracy, stability, and reproducibility and was utilized to simultaneously quantify ten constituents of CQQNC obtained from seven different batches. Conclusion: It is the first time to report the rapid and simultaneous analysis of the ten compounds in CQQNC by HPLC-MS/MS and apply to determine 10 constituents in 7 batches of CQQNC bought from drug store in china. This method could be considered as good quality criteria to control the quality of CQQNC. SUMMARY In this paper, a simple, specific, and rapid high-performance liquid chromatogram coupled with triple-quadrupole mass spectrometry method for simultaneous quantification of ten constituents in Chaiqin Qingning Capsule has been developed for the first time. This method could be considered as good quality criteria to control the quality of CQQNC. Abbreviations used: CHM: Chinese herbal medicine; TCM: Traditional Chinese Medicine; CQQNC: Triple-quadrupole mass spectrometry Chaiqin Qingning Capsules; HPLC–MS/MS: High liquid chromatography equipped with tandem mass spectrometry; ESI: Electrospray ionization; DP: Declustering potential; CE: Collision energy; RSD: Relative standard deviation; LOD: Limit of detection; LOQ: Limit of quantity. PMID:29200714

A new LC-MS/MS bioanalytical method for perindopril and perindoprilat in human plasma and milk.

PubMed

Lwin, Ei Mon Phyo; Gerber, Cobus; Song, Yunmei; Leggett, Catherine; Ritchie, Usha; Turner, Sean; Garg, Sanjay

2017-10-01

A first of its kind, simple, rapid, and sensitive liquid chromatography mass spectrometry (LC-MS/MS) method was developed and validated for quantification of perindopril and perindoprilat in both human plasma and breast milk. The analytes and internal standards (phenazone and acetyl salicylic acid) were extracted from biological matrices by protein precipitation. A Phenomenex® C-18 column was used to provide an appropriate chromatographic separation of the analytes, followed by detection with tandem mass spectrometry. Gradient chromatographic and mass spectrometric detection conditions with mobile phases (A: 5% methanol + 0.1% formic acid in water v/v, and B: 95% methanol + 0.1% formic acid in water v/v) were developed to achieve a LOQ of 0.5 ng/mL in both human plasma and milk. The method was suitable of evaluating clinical samples. The mass transition was followed as m/z 369.10/172.00 for perindopril, m/z 339.00/168.10 for perindoprilat, m/z 188.90/55.95 for phenazone, and m/z 179.04/137.02 for acetyl salicylic acid. The developed method was optimized and validated with a linear range of 0.1-200 ng/mL (r 2  = better than 0.99 for both perindopril and perindoprilat). The precision and accuracy values were within 15% CV. The overall recovery of the analytes was 80-110%. The method has good specificity and repeatability. Stability studies were conducted in both human plasma and bovine milk for up to 3 months, at the storage conditions of 25, 4, and -80 °C.

A validated ultra-performance liquid chromatography–tandem mass spectrometry method for the quantification of polymyxin B in mouse serum and epithelial lining fluid: application to pharmacokinetic studies

PubMed Central

He, Jie; Gao, Song; Hu, Ming; Chow, Diana S.-L.; Tam, Vincent H.

2013-01-01

Objectives A rapid, sensitive and robust ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method was developed for the quantification of four major polymyxin B components (polymyxin B1, polymyxin B2, polymyxin B3 and isoleucine-polymyxin B1) in serum and epithelial lining fluid (ELF) samples. Methods A Waters Acquity UPLC HSS C18 column was used with 0.1% formic acid in water/acetonitrile as mobile phases. Analysis was performed in a positive ionization mode with multiple-reactions monitoring scan type. Five percent trichloroacetic acid was used to precipitate proteins in biological samples and to increase the sensitivity of detection. Results Our results showed a linear concentration range of 0.0065–3.2 mg/L for all the major polymyxin B components in both serum and ELF, respectively; the interday variation was <10% and the accuracy was 88%–115%. The validated method was used to characterize the pharmacokinetics (serum and ELF) of polymyxin B in mice. Conclusions This is the first report, to date, examining the individual pharmacokinetics of various polymyxin B components in mice. Our results revealed no considerable differences in clearances among the components. The limited exposure of polymyxin B in ELF observed was consistent with the less favourable efficacy of polymyxin B reported for the treatment of pulmonary infections. This method can be used to further examine the pharmacokinetics of polymyxin B in a variety of clinical and experimental settings. PMID:23341128

Determination of pesticides in sewage sludge from an agro-food industry using QuEChERS extraction followed by analysis with liquid chromatography-tandem mass spectrometry.

PubMed

Ponce-Robles, Laura; Rivas, Gracia; Esteban, Belen; Oller, Isabel; Malato, Sixto; Agüera, Ana

2017-10-01

An analytical method was developed and validated for the determination of ten pesticides in sewage sludge coming from an agro-food industry. The method was based on the application of Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction for solid sewage sludge and SPE extraction for sludge aqueous phase, followed by liquid chromatography (LC) coupled to hybrid quadrupole/linear ion trap mass spectrometry (QqLIT-MS). The QuEChERS method was reported 14 years ago and nowadays is mainly applied to the analysis of pesticides in food. More recent applications have been reported in other matrices as sewage sludge, but the complexity of the matrix makes necessary the optimization of the cleanup step to improve the efficiency of the analysis. With this aim, several dispersive solid-phase extraction cleanup sorbents were tested, choosing C18 + PSA as a d-SPE sorbent. The proposed method was satisfactorily validated for most compounds investigated, showing recoveries higher than 80% in most cases, with the only exception of prochloraz (71%) at low concentration level. Limits of quantification were lower than 40 ng l -1 in the aqueous phase and below 40 ng g -1 in the solid phase for the majority of the analytes. The method was applied to solid sludge and the sludge aqueous phase coming from an agro-food industry which processes fruits and vegetables. Graphical abstract Application of LC/MS/MS advanced analytical techniques for determination of pesticides contained in sewage sludge.

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry method for the determination of dienogest in human plasma and its pharmacokinetic applications under fasting.

PubMed

Pallapothu, Leela Mohan Kumar; Batta, Neelima; Pigili, Ravi Kumar; Yejella, Rajendra Prasad

2015-02-01

A simple, rapid and sensitive analytical method using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) detection with positive ion electrospray ionization was developed for the determination of dienogest in human K2 EDTA plasma using levonorgestrel d6 as an internal standard (IS). Dienogest and IS were extracted from human plasma using simple liquid-liquid extraction. Chromatographic separation was achieved on a Zorbax XDB-Phenyl column (4.6 × 75 mm, 3.5 µm) under isocratic conditions using acetonitrile-5 mm ammonium acetate (70:30, v/v) at a flow rate of 0.60 mL/min. The protonated precursor to product ion transitions monitored for dienogest and IS were at m/z 312.30 → 135.30 and 319.00 → 251.30, respectively. The method was validated with a linearity range of 1.003-200.896 ng/mL having a total analysis time for each chromatograph of 3.0 min. The method has shown tremendous reproducibility with intra- and inter-day precision (coefficient of variation) <3.97 and 6.10%, respectively, and accuracy within ±4.0% of nominal values. The validated method was applied to a pharmacokinetic study in human plasma samples generated after administration of a single oral dose of 2.0 mg dienogest tablets to healthy female volunteers and was proved to be highly reliable for the analysis of clinical samples. Copyright © 2014 John Wiley & Sons, Ltd.

Validated ultra-performance liquid chromatography-tandem mass spectrometry method for analyzing LSD, iso-LSD, nor-LSD, and O-H-LSD in blood and urine.

PubMed

Chung, Angela; Hudson, John; McKay, Gordon

2009-06-01

The Royal Canadian Mounted Police Forensic Science and Identification Services was looking for a confirmatory method for lysergic acid diethylamide (LSD). As a result, an ultra-performance liquid chromatography-tandem mass spectrometry method was validated for the confirmation and quantitation of LSD, iso-LSD, N-demethyl-LSD (nor-LSD), and 2-oxo-3-hydroxy-LSD (O-H-LSD). Relative retention time and ion ratios were used as identification parameters. Limits of detection (LOD) in blood were 5 pg/mL for LSD and iso-LSD and 10 pg/mL for nor-LSD and O-H-LSD. In urine, the LOD was 10 pg/mL for all analytes. Limits of quantitation (LOQ) in blood and urine were 20 pg/mL for LSD and iso-LSD and 50 pg/mL for nor-LSD and O-H-LSD. The method was linear, accurate, and precise from 10 to 2000 pg/mL in blood and 20 to 2000 pg/mL in urine for LSD and iso-LSD and from 20 to 2000 pg/mL in blood and 50 to 2000 pg/mL in urine for nor-LSD and O-H-LSD with a coefficient of determination (R(2)) > or = 0.99. The method was applied to blinded biological control samples and biological samples taken from a suspected LSD user. This is the first reported detection of O-H-LSD in blood from a suspected LSD user.

Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

PubMed

Lísa, Miroslav; Cífková, Eva; Khalikova, Maria; Ovčačíková, Magdaléna; Holčapek, Michal

2017-11-24

Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements. Copyright © 2017 Elsevier B.V. All rights reserved.

Deconvolving molecular signatures of interactions between microbial colonies

PubMed Central

Harn, Y.-C.; Powers, M. J.; Shank, E. A.; Jojic, V.

2015-01-01

Motivation: The interactions between microbial colonies through chemical signaling are not well understood. A microbial colony can use different molecules to inhibit or accelerate the growth of other colonies. A better understanding of the molecules involved in these interactions could lead to advancements in health and medicine. Imaging mass spectrometry (IMS) applied to co-cultured microbial communities aims to capture the spatial characteristics of the colonies’ molecular fingerprints. These data are high-dimensional and require computational analysis methods to interpret. Results: Here, we present a dictionary learning method that deconvolves spectra of different molecules from IMS data. We call this method MOLecular Dictionary Learning (MOLDL). Unlike standard dictionary learning methods which assume Gaussian-distributed data, our method uses the Poisson distribution to capture the count nature of the mass spectrometry data. Also, our method incorporates universally applicable information on common ion types of molecules in MALDI mass spectrometry. This greatly reduces model parameterization and increases deconvolution accuracy by eliminating spurious solutions. Moreover, our method leverages the spatial nature of IMS data by assuming that nearby locations share similar abundances, thus avoiding overfitting to noise. Tests on simulated datasets show that this method has good performance in recovering molecule dictionaries. We also tested our method on real data measured on a microbial community composed of two species. We confirmed through follow-up validation experiments that our method recovered true and complete signatures of molecules. These results indicate that our method can discover molecules in IMS data reliably, and hence can help advance the study of interaction of microbial colonies. Availability and implementation: The code used in this paper is available at: https://github.com/frizfealer/IMS_project. Contact: vjojic@cs.unc.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26072476

Determination of (2)H-enrichment of rat brain interstitial fluid and rat plasma by headspace-gas-chromatography - quadrupole-mass-spectrometry.

PubMed

Eberl, Anita; Altendorfer-Kroath, Thomas; Kollmann, Denise; Birngruber, Thomas; Sinner, Frank; Raml, Reingard; Magnes, Christoph

2016-09-15

(2)H2O as nonradioactive, stable marker substance is commonly used in preclinical and clinical studies and the precise determination of (2)H2O concentration in biological samples is crucial. However, aside from isotope ratio mass spectrometry (IRMS), only a very limited number of methods to accurately measure the (2)H2O concentration in biological samples are routinely established until now. In this study, we present a straightforward method to accurately measure (2)H-enrichment of rat brain interstitial fluid (ISF) and rat plasma to determine the relative recovery of a cerebral open flow microperfusion (cOFM) probe, using headspace-gas-chromatography - quadrupole-mass-spectrometry. This method is based on basic-catalyzed hydrogen/deuterium exchange in acetone and detects the (2)H-labelled acetone directly by the headspace GC-MS. Small sample volumes and limited number of preparation steps make this method highly competitive. It has been fully validated. (2)H enriched to 8800 ppm in plasma showed an accuracy of 98.9% and %Relative Standard Deviation (RSD) of 3.1 with n = 18 over three days and with two operators. Similar performance was obtained for cerebral ISF enriched to 1100 ppm (accuracy: 96.5%, %RSD: 3.1). With this highly reproducible method we demonstrated the successful employment of (2)H2O as performance marker for a cOFM probe. Copyright © 2016. Published by Elsevier Inc.

Refined methodology for the determination of neonicotinoid pesticides and their metabolites in honey bees and bee products by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

PubMed

Kamel, Alaa

2010-05-26

An analytical method was refined for the extraction and determination of neonicotinoid pesticide residues and their metabolites in honey bees and bee products. Samples were extracted with 2% triethylamine (TEA) in acetonitrile (ACN) followed by salting out, solid phase extraction (SPE) cleanup, and detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated in triplicate at three fortification concentrations in each matrix. Good recoveries were observed for most analytes and ranged between 70 and 120% with relative standard deviations between replicates of <20% in most cases. The method limits of detection were 0.2 ng/g for the parent neonicotinoid pesticides and ranged between 0.2 and 15 ng/g for the neonicotinoid metabolites. This refined method provides lower detection limits and improved recovery of neonicotinoids and their metabolites, which will help researchers evaluate subchronic effects of these pesticides, address data gaps related to colony collapse disorder (CCD), and determine the role of pesticides in pollinator decline.

Optimization of sample preparation by central composite design for multi-class determination of veterinary drugs in bovine muscle, kidney and liver by ultra-high-performance liquid chromatographic-tandem mass spectrometry.

PubMed

Rizzetti, Tiele M; de Souza, Maiara P; Prestes, Osmar D; Adaime, Martha B; Zanella, Renato

2018-04-25

In this study a simple and fast multi-class method for the determination of veterinary drugs in bovine liver, kidney and muscle was developed. The method employed acetonitrile for extraction followed by clean-up with EMR-Lipid® sorbent and trichloracetic acid. Tests indicated that the use of TCA was most effective when added in the final step of the clean-up procedure instead of during extraction. Different sorbents were tested and optimized using central composite design and the analytes determined by ultra-high-performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS). The method was validated according the European Commission Decision 2002/657 presenting satisfactory results for 69 veterinary drugs in bovine liver and 68 compounds in bovine muscle and kidney. The method was applied in real samples and in proficiency tests and proved to be adequate for routine analysis. Residues of abamectin, doramectin, eprinomectin and ivermectin were found in samples of bovine muscle and only ivermectin in bovine liver. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quality evaluation of Desmodium styracifolium using high-performance liquid chromatography with photodiode array detection and electrospray ionisation tandem mass spectrometry.

PubMed

Zhou, Chan; Luo, Jian-Guang; Kong, Ling-Yi

2012-01-01

Desmodium styracifolium, with C-flavone glycosides as main pharmacological effective compounds, is a popular Chinese medicinal herb and has been used to treat urination disturbance, urolithiasis, edema and jaundice. However, few systematic methods have been reported on the quality control of this natural herb. To develop a method for control the quality of D. styracifolium by combining chromatographic fingerprints and major constituent quantification. Separations were performed on an Ultimate XB-C-18 column by gradient elution using acetonitrile and 0.1% aqueous formic acid. Analytes were identified by HPLC coupled with electrospray ionisation mass spectrometry experiments. Twenty common peaks in chromatographic fingerprints were first identified among 15 batches of D. styracifolium from various regions. On basis of this, a HPLC-PAD method was established to simultaneously quantify five major constituents, which was validated for limit of qualification, linearity and interday variation of precision and accuracy. The assay developed could be considered as a suitable quality control method of D. styracifolium. Copyright © 2011 John Wiley & Sons, Ltd.

Liquid chromatography-electrospray ionization tandem mass spectrometry and dynamic multiple reaction monitoring method for determining multiple pesticide residues in tomato.

PubMed

Andrade, G C R M; Monteiro, S H; Francisco, J G; Figueiredo, L A; Botelho, R G; Tornisielo, V L

2015-05-15

A quick and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method, using dynamic multiple reaction monitoring and a 1.8-μm particle size analytical column, was developed to determine 57 pesticides in tomato in a 13-min run. QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for samples preparations and validations was carried out in compliance with EU SANCO guidelines. The method was applied to 58 tomato samples. More than 84% of the compounds investigated showed limits of detection equal to or lower than 5 mg kg(-1). A mild (<20%), medium (20-50%), and strong (>50%) matrix effect was observed for 72%, 25%, and 3% of the pesticides studied, respectively. Eighty-one percent of the pesticides showed recoveries ranging between 70% and 120%. Twelve pesticides were detected in 35 samples, all below the maximum residue levels permitted in the Brazilian legislation; 15 samples exceeded the maximum residue levels established by the EU legislation for methamidophos; and 10 exceeded limits for acephate and four for bromuconazole. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validation of an ultra-high-performance liquid chromatography-tandem mass spectrometry method to quantify illicit drug and pharmaceutical residues in wastewater using accuracy profile approach.

PubMed

Hubert, Cécile; Roosen, Martin; Levi, Yves; Karolak, Sara

2017-06-02

The analysis of biomarkers in wastewater has become a common approach to assess community behavior. This method is an interesting way to estimate illicit drug consumption in a given population: by using a back calculation method, it is therefore possible to quantify the amount of a specific drug used in a community and to assess the consumption variation at different times and locations. Such a method needs reliable analytical data since the determination of a concentration in the ngL -1 range in a complex matrix is difficult and not easily reproducible. The best analytical method is liquid chromatography - mass spectrometry coupling after solid-phase extraction or on-line pre-concentration. Quality criteria are not specially defined for this kind of determination. In this context, it was decided to develop an UHPLC-MS/MS method to analyze 10 illicit drugs and pharmaceuticals in wastewater treatment plant influent or effluent using a pre-concentration on-line system. A validation process was then carried out using the accuracy profile concept as an innovative tool to estimate the probability of getting prospective results within specified acceptance limits. Influent and effluent samples were spiked with known amounts of the 10 compounds and analyzed three times a day for three days in order to estimate intra-day and inter-day variations. The matrix effect was estimated for each compound. The developed method can provide at least 80% of results within ±25% limits except for compounds that are degraded in influent. Copyright © 2017 Elsevier B.V. All rights reserved.

Maximum residue level validation of triclabendazole marker residues in bovine liver, muscle and milk matrices by ultra high pressure liquid chromatography tandem mass spectrometry.

PubMed

Whelan, Michelle; O'Mahony, John; Moloney, Mary; Cooper, Kevin M; Furey, Ambrose; Kennedy, D Glenn; Danaher, Martin

2013-02-01

Triclabendazole is the only anthelmintic drug, which is active against immature, mature and adult stages of fluke. The objective of this work was to develop an analytical method to quantify and confirm the presence of triclabendazole residues around the MRL. In this work, a new analytical method was developed, which extended dynamic range to 1-100 and 5-1000 μg kg(-1) for milk and tissue, respectively. This was achieved using a mobile phase containing trifluoroacetic acid (pK(a) of 0.3), which resulted in the formation of the protonated pseudomolecular ions, [M+H](+), of triclabendazole metabolites. Insufficient ionisation of common mobile phase additives due to low pK(a) values (<2) was identified as the cause of poor linearity. The new mobile phase conditions allowed the analysis of triclabendazole residues in liver, muscle and milk encompassing their EU maximum residue levels (MRL) (250, 225 and 10 μg kg(-1) respectively). Triclabendazole residues were extracted using a modified QuEChERS method and analysed by positive electrospray ionisation mass spectrometry with all analytes eluted by 2.23 min. The method was validated at the MRL according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCα) of the method was in the range of 250.8-287.2, 2554.9-290.8 and 10.9-12.1 μg kg(-1) for liver, muscle and milk, respectively. The performance of the method was successfully verified for triclabendazole in muscle by participating in a proficiency study, the method was also applied to incurred liver, muscle and milk samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrophilic interaction liquid chromatography-tandem mass spectrometry quantitative method for the cellular analysis of varying structures of gemini surfactants designed as nanomaterial drug carriers.

PubMed

Donkuru, McDonald; Michel, Deborah; Awad, Hanan; Katselis, George; El-Aneed, Anas

2016-05-13

Diquaternary gemini surfactants have successfully been used to form lipid-based nanoparticles that are able to compact, protect, and deliver genetic materials into cells. However, what happens to the gemini surfactants after they have released their therapeutic cargo is unknown. Such knowledge is critical to assess the quality, safety, and efficacy of gemini surfactant nanoparticles. We have developed a simple and rapid liquid chromatography electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantitative determination of various structures of gemini surfactants in cells. Hydrophilic interaction liquid chromatography (HILIC) was employed allowing for a short simple isocratic run of only 4min. The lower limit of detection (LLOD) was 3ng/mL. The method was valid to 18 structures of gemini surfactants belonging to two different structural families. A full method validation was performed for two lead compounds according to USFDA guidelines. The HILIC-MS/MS method was compatible with the physicochemical properties of gemini surfactants that bear a permanent positive charge with both hydrophilic and hydrophobic elements within their molecular structure. In addition, an effective liquid-liquid extraction method (98% recovery) was employed surpassing previously used extraction methods. The analysis of nanoparticle-treated cells showed an initial rise in the analyte intracellular concentration followed by a maximum and a somewhat more gradual decrease of the intracellular concentration. The observed intracellular depletion of the gemini surfactants may be attributable to their bio-transformation into metabolites and exocytosis from the host cells. Obtained cellular data showed a pattern that grants additional investigations, evaluating metabolite formation and assessing the subcellular distribution of tested compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Extraction and analysis of intact glucosinolates--a validated pressurized liquid extraction/liquid chromatography-mass spectrometry protocol for Isatis tinctoria, and qualitative analysis of other cruciferous plants.

PubMed

Mohn, Tobias; Cutting, Brian; Ernst, Beat; Hamburger, Matthias

2007-09-28

Glucosinolates have attracted significant interest due to the chemopreventive properties of some of their transformation products. Numerous protocols for the extraction and analysis of glucosinolates have been published, but limited effort has been devoted to optimize and validate crucial extraction parameters and sample preparation steps. We carried out a systematic optimization and validation of a quantitative assay for the direct analysis of intact glucosinolates in Isatis tinctoria leaves (woad, Brassicaceae). Various parameters such as solvent composition, particle size, temperature, and number of required extraction steps were optimized using pressurized liquid extraction (PLE). We observed thermal degradation of glucosinolates at temperatures above 50 degrees C, and loss of >60% within 10min at 100 degrees C, but no enzymatic degradation in the leaf samples at ambient temperature. Excellent peak shape and resolution was obtained by reversed-phase chromatography on a Phenomenex Aqua column using 10mM ammonium formate as ion-pair reagent. Detection was carried out by electrospray ionisation mass spectrometry in the negative ion mode. Analysis of cruciferous vegetables and spices such as broccoli (Brassica oleracea L. var. italica), garden cress (Lepidium sativum L.) and black mustard (Sinapis nigra L.) demonstrated the general applicability of the method.

Determination of Antimycin-A in water by liquid chromatographic/mass spectrometry: single-laboratory validation

USGS Publications Warehouse

Bernardy, Jeffry A.; Hubert, Terrance D.; Ogorek, Jacob M.; Schmidt, Larry J.

2013-01-01

An LC/MS method was developed and validated for the quantitative determination and confirmation of antimycin-A (ANT-A) in water from lakes or streams. Three different water sample volumes (25, 50, and 250 mL) were evaluated. ANT-A was stabilized in the field by immediately extracting it from water into anhydrous acetone using SPE. The stabilized concentrated samples were then transported to a laboratory and analyzed by LC/MS using negative electrospray ionization. The method was determined to have adequate accuracy (78 to 113% recovery), precision (0.77 to 7.5% RSD with samples ≥500 ng/L and 4.8 to 17% RSD with samples ≤100 ng/L), linearity, and robustness over an LOQ range from 8 to 51 600 ng/L.

Determination of antimycin-A in water by liquid chromatographic/mass spectrometry: single-laboratory validation.

PubMed

Bernardy, Jeffry A; Hubert, Terrance D; Ogorek, Jacob M; Schmidt, Larry J

2013-01-01

An LC/MS method was developed and validated for the quantitative determination and confirmation of antimycin-A (ANT-A) in water from lakes or streams. Three different water sample volumes (25, 50, and 250 mL) were evaluated. ANT-A was stabilized in the field by immediately extracting it from water into anhydrous acetone using SPE. The stabilized concentrated samples were then transported to a laboratory and analyzed by LC/MS using negative electrospray ionization. The method was determined to have adequate accuracy (78 to 113% recovery), precision (0.77 to 7.5% RSD with samples > or = 500 ng/L and 4.8 to 17% RSD with samples < or = 100 ng/L), linearity, and robustness over an LOQ range from 8 to 51 600 ng/L.

Rapid and sensitive determination of major polyphenolic components in Euphoria longana Lam. seeds using matrix solid-phase dispersion extraction and UHPLC with hybrid linear ion trap triple quadrupole mass spectrometry.

PubMed

Rathore, Atul S; Sathiyanarayanan, L; Deshpande, Shreekant; Mahadik, Kakasaheb R

2016-11-01

A rapid and sensitive method for the extraction and determination of four major polyphenolic components in Euphoria longana Lam. seeds is presented for the first time based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with hybrid triple quadrupole linear ion trap mass spectrometry. Matrix solid-phase dispersion method was designed for the extraction of Euphoria longana seed constituents and compared with microwave-assisted extraction and ultrasonic-assisted extraction methods. An Ultra high performance liquid chromatography with hybrid triple quadrupole linear ion-trap mass spectrometry method was developed for quantitative analysis in multiple-reaction monitoring mode in negative electrospray ionization. The chromatographic separation was accomplished using an ACQUITY UPLC BEH C 18 (2.1 mm × 50 mm, 1.7 μm) column with gradient elution of 0.1% aqueous formic acid and 0.1% formic acid in acetonitrile. The developed method was validated with acceptable linearity (r 2 > 0.999), precision (RSD ≤ 2.22%) and recovery (RSD ≤ 2.35%). The results indicated that matrix solid-phase dispersion produced comparable extraction efficiency compared with other methods nevertheless was more convenient and time-saving with reduced requirements on sample and solvent volumes. The proposed method is rapid and sensitive in providing a promising alternative for extraction and comprehensive determination of active components for quality control of Euphoria longana products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanomanipulation-Coupled Matrix-Assisted Laser Desorption/ Ionization-Direct Organelle Mass Spectrometry: A Technique for the Detailed Analysis of Single Organelles

NASA Astrophysics Data System (ADS)

Phelps, Mandy S.; Sturtevant, Drew; Chapman, Kent D.; Verbeck, Guido F.

2016-02-01

We describe a novel technique combining precise organelle microextraction with deposition and matrix-assisted laser desorption/ionization (MALDI) for a rapid, minimally invasive mass spectrometry (MS) analysis of single organelles from living cells. A dual-positioner nanomanipulator workstation was utilized for both extraction of organelle content and precise co-deposition of analyte and matrix solution for MALDI-direct organelle mass spectrometry (DOMS) analysis. Here, the triacylglycerol (TAG) profiles of single lipid droplets from 3T3-L1 adipocytes were acquired and results validated with nanoelectrospray ionization (NSI) MS. The results demonstrate the utility of the MALDI-DOMS technique as it enabled longer mass analysis time, higher ionization efficiency, MS imaging of the co-deposited spot, and subsequent MS/MS capabilities of localized lipid content in comparison to NSI-DOMS. This method provides selective organellar resolution, which complements current biochemical analyses and prompts for subsequent subcellular studies to be performed where limited samples and analyte volume are of concern.

[Determination of Al, Be, Cd, Co, Cr, Mn, Ni, Pb, Se and Tl in whole blood by atomic absorption spectrometry without preliminary sample digestion].

PubMed

Ivanenko, N B; Ivanenko, A A; Solov'ev, N D; Navolotskiĭ, D V; Pavlova, O V; Ganeev, A A

2014-01-01

Methods of whole blood trace element determination by Graphite furnace atomic absorption spectrometry (in the variant of Zeeman's modulation polarization spectrometry) have been proposed. They do not require preliminary sample digestion. Furnace programs, modifiers and blood dilution factors were optimized. Seronorm™ human whole blood reference materials were used for validation. Dynamic ranges (for undiluted blood samples) were: Al 8 ¸ 210 мg/L; Be 0.3 ¸ 50 мg/L; Cd 0.2 ¸ 75 мg/L; Сo 5 ¸ 350 мg/L; Cr 10 ¸ 100 мg/L; Mn 6 ¸ 250 мg/L; Ni 10 ¸ 350 мg/L; Pb 3 ¸ 240 мg/L; Se 10 ¸ 500 мg/L; Tl 2 ¸ 600 мg/L. Precision (RSD) for the middle of dynamic range ranged from 5% for Mn to 11 for Se.

Role of Imaging Specrometer Data for Model-based Cross-calibration of Imaging Sensors

NASA Technical Reports Server (NTRS)

Thome, Kurtis John

2014-01-01

Site characterization benefits from imaging spectrometry to determine spectral bi-directional reflectance of a well-understood surface. Cross calibration approaches, uncertainties, role of imaging spectrometry, model-based site characterization, and application to product validation.

Determination of Gentamicin Sulphate Composition and Related Substances in Pharmaceutical Preparations by LC with Charged Aerosol Detection

PubMed Central

Stypulkowska, Karolina; Fijalek, Zbigniew; Sarna, Katarzyna

2010-01-01

A new, simple and repeatable liquid chromatography method with charged aerosol detection (LC-CAD) for the determination of gentamicin sulphate composition and related substances has been developed. Gentamicin lacks of chromophores, therefore its determination is quite problematic. Using a universal CAD enables to achieve good separation without sample derivatization. Mass spectrometry was employed to confirm the LC-CAD peak profile. The proposed method was validated and applied for the determination of gentamicin sulphate composition and related substances in pharmaceutical preparations. PMID:21212825

Design and Validation of In-Source Atmospheric Pressure Photoionization Hydrogen/Deuterium Exchange Mass Spectrometry with Continuous Feeding of D2O.

PubMed

Acter, Thamina; Lee, Seulgidaun; Cho, Eunji; Jung, Maeng-Joon; Kim, Sunghwan

2018-01-01

In this study, continuous in-source hydrogen/deuterium exchange (HDX) atmospheric pressure photoionization (APPI) mass spectrometry (MS) with continuous feeding of D 2 O was developed and validated. D 2 O was continuously fed using a capillary line placed on the center of a metal plate positioned between the UV lamp and nebulizer. The proposed system overcomes the limitations of previously reported APPI HDX-MS approaches where deuterated solvents were premixed with sample solutions before ionization. This is particularly important for APPI because solvent composition can greatly influence ionization efficiency as well as the solubility of analytes. The experimental parameters for APPI HDX-MS with continuous feeding of D 2 O were optimized, and the optimized conditions were applied for the analysis of nitrogen-, oxygen-, and sulfur-containing compounds. The developed method was also applied for the analysis of the polar fraction of a petroleum sample. Thus, the data presented in this study clearly show that the proposed HDX approach can serve as an effective analytical tool for the structural analysis of complex mixtures. Graphical abstract ᅟ.

Determination of 21 antibiotics in sea cucumber using accelerated solvent extraction with in-cell clean-up coupled to ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhu, Minghua; Zhao, Hongxia; Xia, Deming; Du, Juan; Xie, Huaijun; Chen, Jingwen

2018-08-30

An accelerated solvent extraction (ASE) with in-cell clean-up method coupled to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to determine 21 antibiotics in sea cucumber. The analytes include 10 sulfonamides, 4 fluoroquinolones, 3 amphenicols, 2 beta-lactams, 1 lincosamide and trimethoprim. Optimal parameters of ASE method were obtained at 80 °C, 1 static cycle of 5 min with methanol/acetonitrile (1/1, v/v) using 2 g of C18 as adsorbent. Recoveries at 50.1-129.2% were achieved with RSD under 20%. Method detection limits ranged from 0.03 to 2.9 μg kg -1 . Compared to the reported ultrasound-assisted extraction method, the proposed method offered comparable extraction efficiency for sulfonamides from sea cucumber, but higher for other categories of antibiotics. This validated method was then successfully applied to sea cucumber samples and 9 antibiotics were detected with the highest concentration up to 57.7 μg kg -1 for norfloxacin. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pharmacokinetics and tissue distribution study of schisandrin B in rats by ultra-fast liquid chromatography with tandem mass spectrometry.

PubMed

Zhu, Heyun; Zhang, Xiurong; Guan, Jiao; Cui, Baiji; Zhao, Longshan; Zhao, Xu

2013-05-05

A rapid, sensitive and high throughput ultra-fast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) method was established and validated for the determination of schisandrin B in rat plasma and various tissues (including heart, liver, spleen, lung, and kidney). The biological samples were prepared by protein precipitation, and the separation was achieved on a shim-pack XR-ODS C18 column (75 mm × 3.0 mm, 2.2 μm) with a mobile phase consisting of methanol-0.1% formic acid water (85:15, v/v) at a flow rate of 0.4 mL/min. The MS/MS detection was performed on an API 3200 QTRAP mass spectrometry equipped with electrospray ionization (ESI) source using multiple reactions monitoring (MRM) mode by monitoring the fragmentation of m/z 401.2→300.2 for schisandrin B and m/z 271.2→203.1 for imperatorin (internal standard, IS). The calibration curve was linear in the range of 1-500 ng/mL for plasma and tissue homogenates (r ≥ 0.9927). The lower limit of quantification (LLOQ) was 1 ng/mL. The validated method was successfully applied to the pharmacokinetics and tissue distribution study of schisandrin B after oral administration to rats. The pharmacokinetic curve showed double peaks after oral administration, which demonstrated that a hepatoenteral circulation may exist. Tissue distribution showed the highest level was observed in liver, then in kidney, which indicated schisandrin B was mainly accumulated in liver and renal excretion might be a main elimination route. Copyright © 2013 Elsevier B.V. All rights reserved.

LC-MS/MS method for the simultaneous determination of Lys-MCC-DM1, MCC-DM1 and DM1 as potential intracellular catabolites of the antibody-drug conjugate trastuzumab emtansine (T-DM1).

PubMed

Liu, Yazhong; Zhou, Fang; Sang, Hua; Ye, Hui; Chen, Qianying; Yao, Lan; Ni, Ping; Wang, Guangji; Zhang, Jingwei

2017-04-15

Lysine-MCC-DM1, MCC-DM1 and DM1 are potential catabolites of trastuzumab emtansine (T-DM1). A convenient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to detect these catabolites simultaneously in in vitro investigations for the first time. Protein precipitation was utilized to prepare the samples. Chromatographic separation was achieved on a Phenomenex Kinetex C18 column (100×2.1mm, 2.6μm) with mobile-phase gradient elution. The calibration curves of each analyte ranging from 1 to 100nM showed good linearity (r 2 >0.995). The method was validated successfully and applied to the intracellular catabolism and regulation of T-DM1. Copyright © 2017 Elsevier B.V. All rights reserved.

Unravelling associations between unassigned mass spectrometry peaks with frequent itemset mining techniques.

PubMed

Vu, Trung Nghia; Mrzic, Aida; Valkenborg, Dirk; Maes, Evelyne; Lemière, Filip; Goethals, Bart; Laukens, Kris

2014-01-01

Mass spectrometry-based proteomics experiments generate spectra that are rich in information. Often only a fraction of this information is used for peptide/protein identification, whereas a significant proportion of the peaks in a spectrum remain unexplained. In this paper we explore how a specific class of data mining techniques termed "frequent itemset mining" can be employed to discover patterns in the unassigned data, and how such patterns can help us interpret the origin of the unexpected/unexplained peaks. First a model is proposed that describes the origin of the observed peaks in a mass spectrum. For this purpose we use the classical correlative database search algorithm. Peaks that support a positive identification of the spectrum are termed explained peaks. Next, frequent itemset mining techniques are introduced to infer which unexplained peaks are associated in a spectrum. The method is validated on two types of experimental proteomic data. First, peptide mass fingerprint data is analyzed to explain the unassigned peaks in a full scan mass spectrum. Interestingly, a large numbers of experimental spectra reveals several highly frequent unexplained masses, and pattern mining on these frequent masses demonstrates that subsets of these peaks frequently co-occur. Further evaluation shows that several of these co-occurring peaks indeed have a known common origin, and other patterns are promising hypothesis generators for further analysis. Second, the proposed methodology is validated on tandem mass spectrometral data using a public spectral library, where associations within the mass differences of unassigned peaks and peptide modifications are explored. The investigation of the found patterns illustrates that meaningful patterns can be discovered that can be explained by features of the employed technology and found modifications. This simple approach offers opportunities to monitor accumulating unexplained mass spectrometry data for emerging new patterns, with possible applications for the development of mass exclusion lists, for the refinement of quality control strategies and for a further interpretation of unexplained spectral peaks in mass spectrometry and tandem mass spectrometry.

Determination of serum levels of imatinib mesylate in patients with chronic myeloid leukemia: validation and application of a new analytical method to monitor treatment compliance

PubMed Central

Rezende, Vinícius Marcondes; Rivellis, Ariane Julio; Gomes, Melissa Medrano; Dörr, Felipe Augusto; Novaes, Mafalda Megumi Yoshinaga; Nardinelli, Luciana; Costa, Ariel Lais de Lima; Chamone, Dalton de Alencar Fisher; Bendit, Israel

2013-01-01

Objective The goal of this study was to monitor imatinib mesylate therapeutically in the Tumor Biology Laboratory, Department of Hematology and Hemotherapy, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP). A simple and sensitive method to quantify imatinib and its metabolite (CGP74588) in human serum was developed and fully validated in order to monitor treatment compliance. Methods The method used to quantify these compounds in serum included protein precipitation extraction followed by instrumental analysis using high performance liquid chromatography coupled with mass spectrometry. The method was validated for several parameters, including selectivity, precision, accuracy, recovery and linearity. Results The parameters evaluated during the validation stage exhibited satisfactory results based on the Food and Drug Administration and the Brazilian Health Surveillance Agency (ANVISA) guidelines for validating bioanalytical methods. These parameters also showed a linear correlation greater than 0.99 for the concentration range between 0.500 µg/mL and 10.0 µg/mL and a total analysis time of 13 minutes per sample. This study includes results (imatinib serum concentrations) for 308 samples from patients being treated with imatinib mesylate. Conclusion The method developed in this study was successfully validated and is being efficiently used to measure imatinib concentrations in samples from chronic myeloid leukemia patients to check treatment compliance. The imatinib serum levels of patients achieving a major molecular response were significantly higher than those of patients who did not achieve this result. These results are thus consistent with published reports concerning other populations. PMID:23741187

Validation and Determination of the Contents of Acetaldehyde and Formaldehyde in Foods

PubMed Central

Jeong, Hye-Seung; Chung, Hyun; Song, Sang-Hoon; Kim, Cho-Il; Lee, Joon-Goo

2015-01-01

The aim of this study was to develop an efficient quantitative method for the determination of acetaldehyde (AA) and formaldehyde (FA) contents in solid and liquid food matrices. The determination of those compounds was validated and performed using gas chromatography-mass spectrometry combined by solid phase micro-extraction after derivatization with O-(2,3,4,5,6-pentafluoro-benzyl)-hydroxylamine hydrochloride. Validation was carried out in terms of limit of detection, limit of quantitation, linearity, precision, and recovery. Then their contents were analyzed in various food samples including 15 fruits, 22 milk products, 31 alcohol-free beverages, and 13 alcoholic beverages. The highest contents of AA and FA were determined in a white wine (40,607.02 ng/g) and an instant coffee (1,522.46 ng/g), respectively. PMID:26483886

In-house validation of a liquid chromatography-tandem mass spectrometry method for the determination of selective androgen receptor modulators (SARMS) in bovine urine.

PubMed

Schmidt, Kathrin S; Mankertz, Joachim

2018-06-01

A sensitive and robust LC-MS/MS method allowing the rapid screening and confirmation of selective androgen receptor modulators in bovine urine was developed and successfully validated according to Commission Decision 2002/657/EC, chapter 3.1.3 'alternative validation', by applying a matrix-comprehensive in-house validation concept. The confirmation of the analytes in the validation samples was achieved both on the basis of the MRM ion ratios as laid down in Commission Decision 2002/657/EC and by comparison of their enhanced product ion (EPI) spectra with a reference mass spectral library by making use of the QTRAP technology. Here, in addition to the MRM survey scan, EPI spectra were generated in a data-dependent way according to an information-dependent acquisition criterion. Moreover, stability studies of the analytes in solution and in matrix according to an isochronous approach proved the stability of the analytes in solution and in matrix for at least the duration of the validation study. To identify factors that have a significant influence on the test method in routine analysis, a factorial effect analysis was performed. To this end, factors considered to be relevant for the method in routine analysis (e.g. operator, storage duration of the extracts before measurement, different cartridge lots and different hydrolysis conditions) were systematically varied on two levels. The examination of the extent to which these factors influence the measurement results of the individual analytes showed that none of the validation factors exerts a significant influence on the measurement results.

Development of a validated liquid chromatography/tandem mass spectrometry method for the distinction of thyronine and thyronamine constitutional isomers and for the identification of new deiodinase substrates.

PubMed

Piehl, Susanne; Heberer, Thomas; Balizs, Gabor; Scanlan, Thomas S; Köhrle, Josef

2008-10-01

Thyronines (THs) and thyronamines (TAMs) are two groups of endogenous iodine-containing signaling molecules whose representatives differ from each other only regarding the number and/or the position of the iodine atoms. Both groups of compounds are substrates of three deiodinase isozymes, which catalyze the sequential reductive removal of iodine from the respective precursor molecule. In this study, a novel analytical method applying liquid chromatography/tandem mass spectrometry (LC-MS/MS) was developed. This method permitted the unequivocal, simultaneous identification and quantification of all THs and TAMs in the same biological sample. Furthermore, a liquid-liquid extraction procedure permitting the concurrent isolation of all THs and TAMs from biological matrices, namely deiodinase (Dio) reaction mixtures, was established. Method validation experiments with extracted TH and TAM analytes demonstrated that the method was selective, devoid of matrix effects, sensitive, linear over a wide range of analyte concentrations and robust in terms of reproducible recoveries, process efficiencies as well as intra-assay and inter-assay stability parameters. The method was applied to study the deiodination reactions of iodinated THs catalyzed by the three deiodinase isozymes. With the HPLC protocol developed herein, sufficient chromatographic separation of all constitutional TH and TAM isomers was achieved. Accordingly, the position of each iodine atom removed from a TH substrate in a Dio-catalyzed reaction was backtracked unequivocally. While several established deiodination reactions were verified, two as yet unknown reactions, namely the phenolic ring deiodination of 3',5'-diiodothyronine (3',5'-T2) by Dio2 and the tyrosyl ring deiodination of 3-monoiodothyronine (3-T1) by Dio3, were newly identified.

A liquid chromatography - tandem mass spectrometry method to measure a selected panel of uremic retention solutes derived from endogenous and colonic microbial metabolism.

PubMed

de Loor, Henriette; Poesen, Ruben; De Leger, Wout; Dehaen, Wim; Augustijns, Patrick; Evenepoel, Pieter; Meijers, Björn

2016-09-14

Chronic kidney disease (CKD) is associated with an increased risk of mortality and cardiovascular disease, which is, at least partly, mediated by the accumulation of so-called uremic retention solutes. Although there has been an increasing interest in the behavior of these solutes, derived from both the endogenous and colonic microbial metabolism, methods to simultaneously and accurately measure a broad panel of relevant uremic retention solutes remain scarce. We developed a highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. A high throughput sample preparation was used with extraction of analytes from 50 μl serum using Ostro plate technology. For most solutes, stable isotopes labelled metabolites were used as internal standards. Chromatography was achieved using an Acquity UPLC CSH Fluoro Phenyl column. The total run time was 8 min, the mobile phase was a gradient of 0.1% formic acid in Milli-Q water and pure methanol at a flow rate of 0.5 ml min(-1). Detection was performed using a tandem mass spectrometer with alternated positive and negative electrospray ionization. Calibration curves were linear for all solutes. Precision was assessed according to the NCCLS EP5-T guideline, being below 15% for all metabolites. Mean recoveries were between 83 and 104% for all metabolites. The validated method was successfully applied in a cohort of 488 patients with CKD. We developed and validated a sensitive and robust UPLC-MS/MS method for quantification of 15 uremic retention solutes derived from endogenous and colonic microbial metabolism. This method allows for studying the behavior and relevance of these solutes in patients with CKD. Copyright © 2016 Elsevier B.V. All rights reserved.

Headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry for the determination of haloanisoles in sparkling (cava and cider) and non-sparkling (wine) alcoholic beverages.

PubMed

Ruiz-Delgado, Ana; Arrebola-Liébanas, Francisco Javier; Romero-González, Roberto; López-Ruiz, Rosalía; Garrido Frenich, Antonia

2016-10-01

A highly sensitive analytical method was developed to determine 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and 2,3,4,5,6-pentachloroanisole (PCA) in sparkling alcoholic beverages. The method was based on the use of headspace solid-phase microextraction (HS-SPME) using a polydimethylsiloxane (PDMS) fibre. It was coupled to gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) for the detection and quantification of the target haloanisoles. The method was fully automated and no sample preparation was needed. The method was validated for alcoholic beverages. The influence of CO 2 on the extraction efficiency was also evaluated for the studied sparkling drinks (cava and cider). All the calibration curves showed good linearity (R 2  > 0.98) within the tested range (1-50 ng l -1 ). Recoveries were evaluated at three different levels (1, 5 and 50 ng l -1 ) and were always between 71% and 119%. Precision was expressed as relative standard deviation (RSD), and was evaluated as intra- and inter-day precisions, with values ≤ 22% in both cases. Limits of quantitation (LOQs) were ≤ 0.91 ng l -1 , which are below the sensory threshold levels for such compounds in humans. The validated method was applied to commercial samples, 10 cavas and 10 ciders, but it was also used for the analysis of nine red wines and four white wines, demonstrating the further applicability of the proposed method to non-sparkling beverages. TCA was detected in most samples at up to 0.45 ng l -1 .

Comparison of two microextraction methods based on solidification of floating organic droplet for the determination of multiclass analytes in river water samples by liquid chromatography tandem mass spectrometry using Central Composite Design.

PubMed

Asati, Ankita; Satyanarayana, G N V; Patel, Devendra K

2017-09-01

Two low density organic solvents based liquid-liquid microextraction methods, namely Vortex assisted liquid-liquid microextraction based on solidification of floating organic droplet (VALLME-SFO) and Dispersive liquid-liquid microextraction based on solidification of floating organic droplet(DLLME-SFO) have been compared for the determination of multiclass analytes (pesticides, plasticizers, pharmaceuticals and personal care products) in river water samples by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The effect of various experimental parameters on the efficiency of the two methods and their optimum values were studied with the aid of Central Composite Design (CCD) and Response Surface Methodology(RSM). Under optimal conditions, VALLME-SFO was validated in terms of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery for which the respective values were (0.011-0.219ngmL -1 ), (0.035-0.723ngmL -1 ), (0.050-0.500ngmL -1 ), (R 2 =0.992-0.999), (40-56), (80-106%). However, when the DLLME-SFO method was validated under optimal conditions, the range of values of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery were (0.025-0.377ngmL -1 ), (0.083-1.256ngmL -1 ), (0.100-1.000ngmL -1 ), (R 2 =0.990-0.999), (35-49), (69-98%) respectively. Interday and intraday precisions were calculated as percent relative standard deviation (%RSD) and the values were ≤15% for VALLME-SFO and DLLME-SFO methods. Both methods were successfully applied for determining multiclass analytes in river water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Method development and validation for total haloxyfop analysis in infant formulas and related ingredient matrices using liquid chromatography-tandem mass spectrometry.

PubMed

Koesukwiwat, Urairat; Vaclavik, Lukas; Mastovska, Katerina

2018-05-08

According to the European Commission directive 2006/141/EC, haloxyfop residue levels should not exceed 0.003 mg/kg in ready-to-feed infant formula, and the residue definition includes sum of haloxyfop, its esters, salts, and conjugates expressed as haloxyfop. A simple method for total haloxyfop analysis in infant formula and related ingredient matrices was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The sample preparation consisted of an alkaline hydrolysis with methanolic sodium hydroxide to release haloxyfop (parent acid) from its bound forms prior to the extraction with acetonitrile. A mixture of magnesium sulfate (MgSO 4 ) and sodium chloride (NaCl) (4:1, w/w) was added to the extract to induce phase separation and force the analyte into the upper acetonitrile-methanol layer and then a 1-mL aliquot was subsequently cleaned up by dispersive solid phase extraction with 150 mg of MgSO 4 and 50 mg of octadecyl (C 18 ) sorbent. The analytical procedure was developed and carefully optimized to enable low-level, total haloxyfop analysis in a variety of challenging matrices, including infant formulas and their important high-carbohydrate, high-protein, high-fat, and emulsifier ingredients. The final method was validated in two different laboratories by fortifying samples with haloxyfop and haloxyfop-methyl, which was used as a model compound simulating bound forms of the analyte. Mean recoveries of haloxyfop across all fortification levels and evaluated matrices ranged between 92.2 and 114% with repeatability, within-lab reproducibility, and reproducibility RSDs ≤ 14%. Based on the validation results, this method was capable to convert the haloxyfop ester into the parent acid in a wide range of sample types and to reliably identify and quantify total haloxyfop at the target 0.003 mg/kg level in infant formulas (both powdered and ready-to-feed liquid forms). Graphical abstract LC-MS/MS-based workflow for the determination of the total haloxyfop in infant formula and related ingredients.

Determination of calcium, magnesium, sodium, and potassium in foodstuffs by using a microsampling flame atomic absorption spectrometric method after closed-vessel microwave digestion: method validation.

PubMed

Chekri, Rachida; Noël, Laurent; Vastel, Christelle; Millour, Sandrine; Kadar, Ali; Guérin, Thierry

2010-01-01

This paper describes a validation process in compliance with the NFIEN ISO/IEC 17025 standard for the determination of the macrominerals calcium, magnesium, sodium, and potassium in foodstuffs by microsampling with flame atomic absorption spectrometry after closed-vessel microwave digestion. The French Standards Commission (Agence Francaise de Normalisation) standards NF V03-110, NF EN V03-115, and XP T-90-210 were used to evaluate this method. The method was validated in the context of an analysis of the 1322 food samples of the second French Total Diet Study (TDS). Several performance criteria (linearity, LOQ, specificity, trueness, precision under repeatability conditions, and intermediate precision reproducibility) were evaluated. Furthermore, the method was monitored by several internal quality controls. The LOQ values obtained (25, 5, 8.3, and 8.3 mg/kg for Ca, Mg, Na, and K, respectively) were in compliance with the needs of the TDS. The method provided accurate results as demonstrated by a repeatability CV (CVr) of < 7% and a reproducibility CV (CVR) of < 12% for all the elements. Therefore, the results indicated that this method could be used in the laboratory for the routine determination of these four elements in foodstuffs with acceptable analytical performance.

Fast determination of octinoxate and oxybenzone uv filters in swimming pool waters by gas chromatography/mass spectrometry after solid-phase microextraction.

PubMed

Yılmazcan, Ö; Kanakaki, C; Izgi, B; Rosenberg, E

2015-07-01

A fast gas chromatography/mass spectrometry method was developed and validated for the analysis of the potential endocrine disrupters octinoxate and oxybenzone in swimming pool water samples based on the solvent-free solid-phase microextraction technique. The low-pressure gas chromatography/mass spectrometry method used for the fast identification of UV filter substances was compared to a conventional method in terms of sensitivity and speed. The fast method proposed resulted in 2 min runs, leading to an eightfold decrease in the total analysis time and a sevenfold improvement in detection limits. The main parameters affecting the solid-phase microextraction process were also studied in detail and the optimized conditions were as follows: fiber coating, polyacrylate; extraction mode, direct immersion; extraction temperature, 25°C; sample volume, 5 mL; extraction time 45 min; pH 6.5. Under the optimized conditions, a linear response was obtained in the concentration range of 0.5-25 μg/L with correlation coefficients in the range 0.990-0.999. The limits of detection were 0.17-0.29 μg/L, and the recoveries were 80-83%. Combined method uncertainty was assessed and found to be less than 7% for both analytes for concentrations equal to or higher than 5 μg/L. Pool water samples were analyzed to demonstrate the applicability of the proposed method. Neither octinoxate nor oxybenzone were detected in the swimming pool water samples at concentrations above the respective limits of detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate using stable isotope dilution liquid chromatography with atmospheric-pressure photoionization tandem mass spectrometry.

PubMed

Zhang, Xiaotao; Hou, Hongwei; Chen, Huan; Liu, Yong; Wang, An; Hu, Qingyuan

2015-09-17

A stable isotope dilution liquid chromatography with tandem mass spectrometry method for the analysis of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate was developed and validated. Compared with previously reported methods, this method has lower limits of detection (0.04-1.35 ng/cig). Additionally, the proposed method saves time, reduces the number of separation steps, and reduces the quantity of solvent needed. The new method was applied to evaluate polycyclic aromatic hydrocarbon content in 213 commercially available cigarettes in China, under the International Standardization Organization smoking regime and the Health Canadian intense smoking regime. The results showed that the total polycyclic aromatic hydrocarbon content was more than two times higher in samples from the Health Canadian intense smoking regime than in samples from the International Standardization Organization smoking regime (1189.23 vs. 2859.50 ng/cig, p<0.05). Meanwhile, the concentration of individual polycyclic aromatic hydrocarbons (and total polycyclic aromatic hydrocarbons) increased with labeled tar content in both of the tested smoking regimes. There was a positive correlation between total polycyclic aromatic hydrocarbons under the International Standardization Organization smoking regime with that under the Health Canadian intense smoking regime. The proposed liquid chromatography with tandem mass spectrometry method is satisfactory for the rapid, sensitive, and accurately quantitative evaluation of polycyclic aromatic hydrocarbon content in cigarette smoke condensate, and it can be applied to assess potential health risks from smoking. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Development and validation of an LC-MS method for determination of Karanjin in rat plasma: application to preclinical pharmacokinetics.

PubMed

Yi, Deliang; Wang, Zhihua; Yi, Longzhi

2015-04-01

A selective and sensitive liquid chromatography-mass spectrometry (MS) method was developed and validated for the determination of karanjin in rat plasma. The target analyte, together with the internal standard (warfarin), was extracted from rat plasma by liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a ZORBAX SB-C18 column using a mixture of acetonitrile and 0.1% aqueous formic acid as the mobile phase with linear gradient elution. MS detection was performed on a single quadrupole MS by selected ion monitoring mode via a positive electrospray ionization source. The assay exhibited a linear dynamic range of 2.50-3,000 ng/mL for karanjin. The intra- and inter-day precision was <10.8%, and the intra- and inter-day accuracy was <9.2%. The validated method has been applied to the preclinical pharmacokinetic studies of karanjin following oral administration of 5, 10 and 20 mg/kg karanjin to rats. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of multi-residue and multi-class antibiotics in aquaculture shrimps by UPLC-MS/MS.

PubMed

Saxena, Sushil Kumar; Rangasamy, Rajesh; Krishnan, Anoop A; Singh, Dhirendra P; Uke, Sumedh P; Malekadi, Praveen Kumar; Sengar, Anoop S; Mohamed, D Peer; Gupta, Ananda

2018-09-15

An accurate, reliable and fast multi-residue, multi-class method using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated for simultaneous determination and quantification of 24 pharmacologically active substances of three different classes (Quinolones including fluoroquinolones, sulphonamides and tetracyclines) in aquaculture shrimps. Sample preparation involves extraction with acetonitrile containing 0.1% formic acid and followed by clean up with n-hexane and 0.1% methanol in water by UPLC-MS/MS within 8 min. The method was validated according to European Commission Decision 2002/657. Acceptable values were obtained for linearity (5-200 μg kg -1 ), specificity, Limit of Quantification (5-10 μg kg -1 ), recovery (between 83 and 100%), repeatability (RSD < 9%), within lab reproducibility (RSD < 15%), reproducibility (RSD ≤ 22%), decision limit (105-116 μg kg -1 ) and detection capability (110-132 μg kg -1 ). The validated method was applied to aquaculture shrimp samples from India. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validation of a liquid chromatography-electrospray ionization tandem mass spectrometric method to determine six polyether ionophores in raw, UHT, pasteurized and powdered milk.

PubMed

Pereira, Mararlene Ulberg; Spisso, Bernardete Ferraz; Jacob, Silvana do Couto; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; Carlos, Betânia de Souza; da Nóbrega, Armi Wanderley

2016-04-01

This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous determination of apatinib and its four major metabolites in human plasma using liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

PubMed

Ding, Juefang; Chen, Xiaoyan; Dai, Xiaojian; Zhong, Dafang

2012-05-01

Apatinib, also known as YN968D1, is a novel antiangiogenic agent that selectively inhibits vascular endothelial growth factor receptor-2. Currently, apatinib is undergoing phase II/III clinical trials in China for the treatment of solid tumors. Apatinib is extensively metabolized in humans, and its major metabolites in circulation include cis-3-hydroxy-apatinib (M1-1), trans-3-hydroxy-apatinib (M1-2), apatinib-25-N-oxide (M1-6), and cis-3-hydroxy-apatinib-O-glucuronide (M9-2). To investigate the pharmacokinetics of apatinib and its four major metabolites in patients with advanced colorectal cancer, a sensitive and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of apatinib, M1-1, M1-2, M1-6, and M9-2 in human plasma. After a simple protein precipitation using acetonitrile as the precipitation solvent, all the analytes and the internal standard vatalanib were separated on a Zorbax Eclipse XDB C(18) column (50 mm × 4.6 mm, 1.8 μm, Agilent) using acetonitrile: 5 mmol/L ammonium acetate with 0.1% formic acid as the mobile phase with gradient elution. A chromatographic total run time of 9 min was achieved. Mass spectrometry detection was conducted through electrospray ionization in positive ion multiple reaction monitoring modes. The method was linear over the concentration range of 3.00-2000 ng/mL for each analyte. The lower limit of quantification for each analyte was 3.00 ng/mL. The intra-assay precision for all the analytes was less than 11.3%, the inter-assay precision was less than 13.8%, and the accuracy was between -5.8% and 3.3%. The validated method was successfully applied to a clinical pharmacokinetic study following oral administration of 500 mg apatinib mesylate in patients with advanced colorectal cancer. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous Determination of Ten Constituents in Chaiqin Qingning Capsule by High-performance Liquid Chromatography Coupled with Triple-quadrupole Mass Spectrometry.

PubMed

Li, Ting Yu; Huo, Xiao Kui; Zheng, Lu; Wang, Chao; Cong, Hai Jian; Xiang, Ting; Zhang, Lin; Zhang, Bao Jing; Huang, Shan Shan; Wu, Bin; Li, Xin Yu

2017-01-01

Chaiqin Qingning Capsule (CQQNC) was a prescription of Traditional Chinese Medicine with the effects of clearing away heat and removing toxin, harmonizing the exterior and interior, it was widely used in Asian, for example, China and Japan, different batches of the raws materials and different processing time may be the vital factor which raised a challenge to control the quality of the CQQNC. In this experiment, a high-performance liquid chromatography-mass spectrometry/MS (HPLC-MS/MS) method was developed to simultaneously determine ten bioactive components for the quality control of CQQNC. Chromatographic separation was achieved using an XBridge BEH C18 column (150 mm × 4.6 mm, 2.5 μm) with a mobile phase composed of 10 mm aqueous ammonium acetate and acetonitrile using a gradient elution in 20 min. This study was conducted by multiple reaction monitoring mode through electrospray ionization resource with a negative ionization mode. The established method was validated with good performance of precision, accuracy, stability, and reproducibility and was utilized to simultaneously quantify ten constituents of CQQNC obtained from seven different batches. It is the first time to report the rapid and simultaneous analysis of the ten compounds in CQQNC by HPLC-MS/MS and apply to determine 10 constituents in 7 batches of CQQNC bought from drug store in china. This method could be considered as good quality criteria to control the quality of CQQNC. In this paper, a simple, specific, and rapid high-performance liquid chromatogram coupled with triple-quadrupole mass spectrometry method for simultaneous quantification of ten constituents in Chaiqin Qingning Capsule has been developed for the first time. This method could be considered as good quality criteria to control the quality of CQQNC. Abbreviations used: CHM: Chinese herbal medicine; TCM: Traditional Chinese Medicine; CQQNC: Triple-quadrupole mass spectrometry Chaiqin Qingning Capsules; HPLC-MS/MS: High liquid chromatography equipped with tandem mass spectrometry; ESI: Electrospray ionization; DP: Declustering potential; CE: Collision energy; RSD: Relative standard deviation; LOD: Limit of detection; LOQ: Limit of quantity.

Comparative Validation of the Determination of Sofosbuvir in Pharmaceuticals by Several Inexpensive Ecofriendly Chromatographic, Electrophoretic, and Spectrophotometric Methods.

PubMed

El-Yazbi, Amira F

2017-01-20

Sofosbuvir (SOFO) was approved by the U.S. Food and Drug Administration in 2013 for the treatment of hepatitis C virusinfection with enhanced antiviral potency compared with earlier analogs. Notwithstanding, all current editions of the pharmacopeias still do not present any analytical methods for the quantification of SOFO. Thus, rapid, simple, and ecofriendly methods for the routine analysis of commercial formulations of SOFO are desirable. In this study, five accurate methods for the determination of SOFO in pharmaceutical tablets were developed and validated. These methods include HPLC, capillary zone electrophoresis, HPTLC, and UV spectrophotometric and derivative spectrometry methods. The proposed methods proved to be rapid, simple, sensitive, selective, and accurate analytical procedures that were suitable for the reliable determination of SOFO in pharmaceutical tablets. An analysis of variance test with <em>P</em>-value &#x003E; 0.05 confirmed that there were no significant differences between the proposed assays. Thus, any of these methods can be used for the routine analysis of SOFO in commercial tablets.

Quantification of doping compounds in faecal samples from racing pigeons, by liquid chromatography-tandem mass spectrometry.

PubMed

Moreira, Fernando X; Silva, Renata; André, Maria B; de Pinho, Paula G; Bastos, Maria L; Ruivo, João; Ruivo, Patrícia; Carmo, Helena

2018-07-01

The use of performance enhancing drugs is not only common in humans, but also in animal sports, including racing of horses, greyhounds and pigeons. The development of accurate analytical procedures to detect doping agents in sports is crucial in order to protect the fair-play of the game, avoid financial fraud in the attribution of eventual awards and, even more important, to protect the animals from harmful drugs and/or dangerous dosage regimens. The present study aimed to develop and validate, a method that enabled the screening and confirmation of the presence of a beta-agonist (clenbuterol) and three corticosteroids (betamethasone, prednisolone and budesonide) in faeces from pigeons. The extraction procedure entailed the combination of liquid-liquid extraction with solid-phase extraction and the analysis was performed by liquid- chromatography coupled to tandem mass spectrometry, with a single 15 minute chromatographic run-time. The method was validated concerning selectivity, linearity (with coefficients of determination always >0.99), accuracy (87.5-114.9%), inter-day and intra-day precisions, limits of detection (0.14-1.81 ng/g) and limits of quantification (0.49-6.08 ng/g), stability and extraction recovery (71.0%-99.3%). The method was successfully applied for the analysis of samples from two pigeons that had been orally administered betamethasone, demonstrating its suitability for doping control purposes. Copyright © 2018. Published by Elsevier B.V.

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.

Diagnostic microbiology in veterinary dermatology: present and future.

PubMed

Guardabassi, Luca; Damborg, Peter; Stamm, Ivonne; Kopp, Peter A; Broens, Els M; Toutain, Pierre-Louis

2017-02-01

The microbiology laboratory can be perceived as a service provider rather than an integral part of the healthcare team. The aim of this review is to discuss the current challenges of providing a state-of-the-art diagnostic veterinary microbiology service including the identification (ID) and antimicrobial susceptibility testing (AST) of key pathogens in veterinary dermatology. The Study Group for Veterinary Microbiology (ESGVM) of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) identified scientific, technological, educational and regulatory issues impacting the predictive value of AST and the quality of the service offered by microbiology laboratories. The advent of mass spectrometry has significantly reduced the time required for ID of key pathogens such as Staphylococcus pseudintermedius. However, the turnaround time for validated AST methods has remained unchanged for many years. Beyond scientific and technological constraints, AST methods are not harmonized and clinical breakpoints for some antimicrobial drugs are either missing or inadequate. Small laboratories, including in-clinic laboratories, are usually not adequately equipped to run up-to-date clinical microbiologic diagnostic tests. ESGVM recommends the use of laboratories employing mass spectrometry for ID and broth micro-dilution for AST, and offering assistance by expert microbiologists on pre- and post-analytical issues. Setting general standards for veterinary clinical microbiology, promoting antimicrobial stewardship, and the development of new, validated and rapid diagnostic methods, especially for AST, are among the missions of ESGVM. © 2017 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of the ESVD and ACVD.

High-throughput quantification of the levels and labeling abundance of free amino acids by liquid chromatography tandem mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cocuron, Jean-Christophe; Tsogtbaatar, Enkhtuul; Alonso, Ana P.

Accurate assessment of mass isotopomer distributions (MIDs) of intracellular metabolites, such as free amino acids (AAs), is crucial for quantifying in vivo fluxes. To date, the majority of studies that measured AA MIDs have relied on the analysis of proteinogenic rather than free AAs by: i) GC–MS, which involved cumbersome process of derivatization, or ii) NMR, which requires large quantities of biological sample. In this work, the development and validation of a high-throughput LC–MS/MS method allowing the quantification of the levels and labeling of free AAs is described. Sensitivity in the order of the femtomol was achieved using multiple reactionmore » monitoring mode (MRM). The MIDs of all free AAs were assessed without the need of derivatization, and were validated (except for Trp) on a mixture of unlabeled AA standards. Finally, this method was applied to the determination of the 13C-labeling abundance in free AAs extracted from maize embryos cultured with 13C-glutamine or 13C-glucose. Although Cys was below the limit of detection in these biological samples, the MIDs of a total of 18 free AAs were successfully determined. Due to the increased application of tandem mass spectrometry for 13C-Metabolic Flux Analysis, this novel method will enable the assessment of more complete and accurate labeling information of intracellular AAs, and therefore a better definition of the fluxes.« less

Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method Coupled with Dispersive Solid-Phase Extraction for Simultaneous Quantification of Eight Paralytic Shellfish Poisoning Toxins in Shellfish

PubMed Central

Yang, Xianli; Zhou, Lei; Tan, Yanglan; Shi, Xizhi; Zhao, Zhiyong; Nie, Dongxia; Zhou, Changyan; Liu, Hong

2017-01-01

In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of eight paralytic shellfish poisoning (PSP) toxins, including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins (GTX1–4) and the N-sulfo carbamoyl toxins C1 and C2, in sea shellfish. The samples were extracted by acetonitrile/water (80:20, v/v) with 0.1% formic and purified by dispersive solid-phase extraction (dSPE) with C18 silica and acidic alumina. Qualitative and quantitative detection for the target toxins were conducted under the multiple reaction monitoring (MRM) mode by using the positive electrospray ionization (ESI) mode after chromatographic separation on a TSK-gel Amide-80 HILIC column with water and acetonitrile. Matrix-matched calibration was used to compensate for matrix effects. The established method was further validated by determining the linearity (R2 ≥ 0.9900), average recovery (81.52–116.50%), sensitivity (limits of detection (LODs): 0.33–5.52 μg·kg−1; limits of quantitation (LOQs): 1.32–11.29 μg·kg−1) and precision (relative standard deviation (RSD) ≤ 19.10%). The application of this proposed approach to thirty shellfish samples proved its desirable performance and sufficient capability for simultaneous determination of multiclass PSP toxins in sea foods. PMID:28661471

High-throughput quantification of the levels and labeling abundance of free amino acids by liquid chromatography tandem mass spectrometry

DOE PAGES

Cocuron, Jean-Christophe; Tsogtbaatar, Enkhtuul; Alonso, Ana P.

2017-02-16

Accurate assessment of mass isotopomer distributions (MIDs) of intracellular metabolites, such as free amino acids (AAs), is crucial for quantifying in vivo fluxes. To date, the majority of studies that measured AA MIDs have relied on the analysis of proteinogenic rather than free AAs by: i) GC–MS, which involved cumbersome process of derivatization, or ii) NMR, which requires large quantities of biological sample. In this work, the development and validation of a high-throughput LC–MS/MS method allowing the quantification of the levels and labeling of free AAs is described. Sensitivity in the order of the femtomol was achieved using multiple reactionmore » monitoring mode (MRM). The MIDs of all free AAs were assessed without the need of derivatization, and were validated (except for Trp) on a mixture of unlabeled AA standards. Finally, this method was applied to the determination of the 13C-labeling abundance in free AAs extracted from maize embryos cultured with 13C-glutamine or 13C-glucose. Although Cys was below the limit of detection in these biological samples, the MIDs of a total of 18 free AAs were successfully determined. Due to the increased application of tandem mass spectrometry for 13C-Metabolic Flux Analysis, this novel method will enable the assessment of more complete and accurate labeling information of intracellular AAs, and therefore a better definition of the fluxes.« less

Analysis of endocrine disruptor compounds in marine sediments by in cell clean up-pressurized liquid extraction-liquid chromatography tandem mass spectrometry determination.

PubMed

Salgueiro-González, N; Turnes-Carou, I; Muniategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

2014-12-10

A less time-, solvent- and sorbent-consuming analytical methodology for the determination of bisphenol A and alkylphenols (4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, nonylphenol) in marine sediment was developed and validated. The method was based on selective pressurized liquid extraction (SPLE) with a simultaneous in cell clean up combined with liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode (LC-ESI-MS/MS). The SPLE extraction conditions were optimized by a Plackett-Burman design followed by a central composite design. Quantitation was performed by standard addition curves in order to correct matrix effects. The analytical features of the method were satisfactory: relative recoveries varied between 94 and 100% and repeatability and intermediate precision were <6% for all compounds. Uncertainty assessment of measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) ranged between 0.17 (4-n-nonylphenol) and 4.01 ng g(-1) dry weight (nonylphenol). Sensitivity, selectivity, automaticity and fastness are the main advantages of this green methodology. As an application, marine sediment samples from Galicia coast (NW of Spain) were analysed. Nonylphenol and 4-tert-octylphenol were measured in all samples at concentrations between 20.1 and 1409 ng g(-1) dry weight, respectively. Sediment toxicity was estimated and no risk to aquatic biota was found. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous quantification of Aroclor mixtures in soil samples by gas chromatography/mass spectrometry with solid phase microextraction using partial least-squares regression.

PubMed

Zhang, Mengliang; Harrington, Peter de B

2015-01-01

Multivariate partial least-squares (PLS) method was applied to the quantification of two complex polychlorinated biphenyls (PCBs) commercial mixtures, Aroclor 1254 and 1260, in a soil matrix. PCBs in soil samples were extracted by headspace solid phase microextraction (SPME) and determined by gas chromatography/mass spectrometry (GC/MS). Decachlorinated biphenyl (deca-CB) was used as internal standard. After the baseline correction was applied, four data representations including extracted ion chromatograms (EIC) for Aroclor 1254, EIC for Aroclor 1260, EIC for both Aroclors and two-way data sets were constructed for PLS-1 and PLS-2 calibrations and evaluated with respect to quantitative prediction accuracy. The PLS model was optimized with respect to the number of latent variables using cross validation of the calibration data set. The validation of the method was performed with certified soil samples and real field soil samples and the predicted concentrations for both Aroclors using EIC data sets agreed with the certified values. The linear range of the method was from 10μgkg(-1) to 1000μgkg(-1) for both Aroclor 1254 and 1260 in soil matrices and the detection limit was 4μgkg(-1) for Aroclor 1254 and 6μgkg(-1) for Aroclor 1260. This holistic approach for the determination of mixtures of complex samples has broad application to environmental forensics and modeling. Copyright © 2014 Elsevier Ltd. All rights reserved.

Method validation and reconnaissance of pharmaceuticals, personal care products, and alkylphenols in surface waters, sediments, and mussels in an urban estuary.

PubMed

Klosterhaus, Susan L; Grace, Richard; Hamilton, M Coreen; Yee, Donald

2013-04-01

Novel methods utilizing liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry were validated for low-level detection of 104 pharmaceuticals and personal care products ingredients (PPCPs) and four alkylphenols (APs) in environmental samples. The methods were applied to surface water, sediment, and mussel tissue samples collected from San Francisco Bay, CA, USA, an urban estuary that receives direct discharge from over forty municipal and industrial wastewater outfalls. Among the target PPCPs, 35% were detected in at least one sample, with 31, 10, and 17 compounds detected in water, sediment, and mussels, respectively. Maximum concentrations were 92 ng/L in water (valsartan), 33 ng/g dry weight (dw) in sediments (triclocarban), and 14 ng/g wet weight (ww) in mussels (N,N-diethyl-m-toluamide). Nonylphenol was detected in water (<2-73 ng/L), sediments (22-86 ng/g dw), and mussels (<0.04-95 ng/g ww), and nonylphenol mono- and diethoxylates were detected in sediments (<1-40 ng/g dw) and mussels (<5-192 ng/g ww). The concentrations of PPCPs and APs detected in the San Francisco Bay samples were generally at least an order of magnitude below concentrations expected to elicit toxic effects in aquatic organisms. This study represents the first reconnaissance of PPCPs in mussels living in an urban estuary and provides the first field-derived bioaccumulation factors (BAFs) for select compounds in aquatic organisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development and validation of a liquid chromatography isotope dilution mass spectrometry method for the reliable quantification of alkylphenols in environmental water samples by isotope pattern deconvolution.

PubMed

Fabregat-Cabello, Neus; Sancho, Juan V; Vidal, Andreu; González, Florenci V; Roig-Navarro, Antoni Francesc

2014-02-07

We present here a new measurement method for the rapid extraction and accurate quantification of technical nonylphenol (NP) and 4-t-octylphenol (OP) in complex matrix water samples by UHPLC-ESI-MS/MS. The extraction of both compounds is achieved in 30min by means of hollow fiber liquid phase microextraction (HF-LPME) using 1-octanol as acceptor phase, which provides an enrichment (preconcentration) factor of 800. On the other hand we have developed a quantification method based on isotope dilution mass spectrometry (IDMS) and singly (13)C1-labeled compounds. To this end the minimal labeled (13)C1-4-(3,6-dimethyl-3-heptyl)-phenol and (13)C1-t-octylphenol isomers were synthesized, which coelute with the natural compounds and allows the compensation of the matrix effect. The quantification was carried out by using isotope pattern deconvolution (IPD), which permits to obtain the concentration of both compounds without the need to build any calibration graph, reducing the total analysis time. The combination of both extraction and determination techniques have allowed to validate for the first time a HF-LPME methodology at the required levels by legislation achieving limits of quantification of 0.1ngmL(-1) and recoveries within 97-109%. Due to the low cost of HF-LPME and total time consumption, this methodology is ready for implementation in routine analytical laboratories. Copyright © 2013 Elsevier B.V. All rights reserved.

Ultra-high performance liquid chromatography with tandem mass spectrometry method for the simultaneous quantitation of five phthalides in rat plasma: Application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and herb-pair extract.

PubMed

Ma, Wen; Wang, Weihui; Peng, Yan; Bian, Qiaoxia; Wang, Nannan; Lee, David Y-W; Dai, Ronghua

2016-06-01

A fast, sensitive, and reliable ultra-high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the simultaneous quantitation and pharmacokinetic study of five phthalides (senkyunolide A, ligustilide, butylidenephthalide, 3-butylphthalide, and levistilide A) in rat plasma after oral administration of Huo Luo Xiao Ling Dan (HLXLD) or Angelica sinensis--Ligusticum chuanxiong herb pair (DG-CX) between normal and arthritis rats. After extraction from blood, the analytes and internal standard were subjected to ultra-high performance liquid chromatography with a Shim-pack XR-ODS column (75 × 3.0 mm(2) , 2.2 μm particles) and mobile phase was composed of methanol and water (containing 0.05% formic acid) under gradient elution conditions, with an electrospray ionization source in the positive ionization and multiple reaction monitoring mode. The lower limits of quantification were 0.192-0.800 ng/mL for all the analytes. Satisfactory linearity, precision, accuracy, mean extraction recovery, and acceptable matrix effect have been achieved. The validated method was successfully applied to a comparative pharmacokinetic study of five bioactive components in rat plasma after oral administration of HLXLD or DG-CX alone, respectively, between normal and arthritic rats. The results showed that there were unlike characters of pharmacokinetics among different groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In house validation of a high resolution mass spectrometry Orbitrap-based method for multiple allergen detection in a processed model food.

PubMed

Pilolli, Rosa; De Angelis, Elisabetta; Monaci, Linda

2018-02-13

In recent years, mass spectrometry (MS) has been establishing its role in the development of analytical methods for multiple allergen detection, but most analyses are being carried out on low-resolution mass spectrometers such as triple quadrupole or ion traps. In this investigation, performance provided by a high resolution (HR) hybrid quadrupole-Orbitrap™ MS platform for the multiple allergens detection in processed food matrix is presented. In particular, three different acquisition modes were compared: full-MS, targeted-selected ion monitoring with data-dependent fragmentation (t-SIM/dd2), and parallel reaction monitoring. In order to challenge the HR-MS platform, the sample preparation was kept as simple as possible, limited to a 30-min ultrasound-aided protein extraction followed by clean-up with disposable size exclusion cartridges. Selected peptide markers tracing for five allergenic ingredients namely skim milk, whole egg, soy flour, ground hazelnut, and ground peanut were monitored in home-made cookies chosen as model processed matrix. Timed t-SIM/dd2 was found the best choice as a good compromise between sensitivity and accuracy, accomplishing the detection of 17 peptides originating from the five allergens in the same run. The optimized method was validated in-house through the evaluation of matrix and processing effects, recoveries, and precision. The selected quantitative markers for each allergenic ingredient provided quantification of 60-100 μg ingred /g allergenic ingredient/matrix in incurred cookies.

Development and validation of a rapid multi-class method for the confirmation of fourteen prohibited medicinal additives in pig and poultry compound feed by liquid chromatography-tandem mass spectrometry.

PubMed

Cronly, Mark; Behan, P; Foley, B; Malone, E; Earley, S; Gallagher, M; Shearan, P; Regan, L

2010-12-01

A confirmatory method has been developed to allow for the analysis of fourteen prohibited medicinal additives in pig and poultry compound feed. These compounds are prohibited for use as feed additives although some are still authorised for use in medicated feed. Feed samples are extracted by acetonitrile with addition of sodium sulfate. The extracts undergo a hexane wash to aid with sample purification. The extracts are then evaporated to dryness and reconstituted in initial mobile phase. The samples undergo an ultracentrifugation step prior to injection onto the LC-MS/MS system and are analysed in a run time of 26 min. The LC-MS/MS system is run in MRM mode with both positive and negative electrospray ionisation. The method was validated over three days and is capable of quantitatively analysing for metronidazole, dimetridazole, ronidazole, ipronidazole, chloramphenicol, sulfamethazine, dinitolimide, ethopabate, carbadox and clopidol. The method is also capable of qualitatively analysing for sulfadiazine, tylosin, virginiamycin and avilamycin. A level of 100 microg kg(-1) was used for validation purposes and the method is capable of analysing to this level for all the compounds. Validation criteria of trueness, precision, repeatability and reproducibility along with measurement uncertainty are calculated for all analytes. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Determination of tigecycline in turkey plasma by LC-MS/MS: validation and application in a pharmacokinetic study.

PubMed

Jasiecka-Mikołajczyk, A; Jaroszewski, J J

2017-03-01

Tigecycline (TIG), a novel glycylcycline antibiotic, plays an important role in the management of complicated skin and intra-abdominal infections. The available data lack any description of a method for determination of TIG in avian plasma. In our study, a selective, accurate and reversed-phase high performance liquid chromatography-tandem mass spectrometry method was developed for the determination of TIG in turkey plasma. Sample preparation was based on protein precipitation and liquid-liquid extraction using 1,2-dichloroethane. Chromatographic separation of TIG and minocycline (internal standard, IS) was achieved on an Atlantis T3 column (150 mm × 3.0 mm, 3.0 μm) using gradient elution. The selected reaction monitoring transitions were performed at 293.60 m/z → 257.10 m/z for TIG and 458.00 m/z → 441.20 m/z for IS. The developed method was validated in terms of specificity, selectivity, linearity, lowest limit of quantification, limit of detection, precision, accuracy, matrix effect, carry-over effect, extraction recovery and stability. All parameters of the method submitted to validation met the acceptance criteria. The assay was linear over the concentration range of 0.01-100 μg/ml. This validated method was successfully applied to a TIG pharmacokinetic study in turkey after intravenous and oral administration at a dose of 10 mg/kg at various time-points.

Comparison of Ambient and Atmospheric Pressure Ion Sources for Cystic Fibrosis Exhaled Breath Condensate Ion Mobility-Mass Spectrometry Metabolomics

NASA Astrophysics Data System (ADS)

Zang, Xiaoling; Pérez, José J.; Jones, Christina M.; Monge, María Eugenia; McCarty, Nael A.; Stecenko, Arlene A.; Fernández, Facundo M.

2017-08-01

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The vast majority of the mortality is due to progressive lung disease. Targeted and untargeted CF breath metabolomics investigations via exhaled breath condensate (EBC) analyses have the potential to expose metabolic alterations associated with CF pathology and aid in assessing the effectiveness of CF therapies. Here, transmission-mode direct analysis in real time traveling wave ion mobility spectrometry time-of-flight mass spectrometry (TM-DART-TWIMS-TOF MS) was tested as a high-throughput alternative to conventional direct infusion (DI) electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) methods, and a critical comparison of the three ionization methods was conducted. EBC was chosen as the noninvasive surrogate for airway sampling over expectorated sputum as EBC can be collected in all CF subjects regardless of age and lung disease severity. When using pooled EBC collected from a healthy control, ESI detected the most metabolites, APCI a log order less, and TM-DART the least. TM-DART-TWIMS-TOF MS was used to profile metabolites in EBC samples from five healthy controls and four CF patients, finding that a panel of three discriminant EBC metabolites, some of which had been previously detected by other methods, differentiated these two classes with excellent cross-validated accuracy.

Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: A multivariate study

NASA Astrophysics Data System (ADS)

Arain, Salma Aslam; Kazi, Tasneem G.; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

2014-12-01

An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046 μg L-1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.

A standards-based method for compositional analysis by energy dispersive X-ray spectrometry using multivariate statistical analysis: application to multicomponent alloys.

PubMed

Rathi, Monika; Ahrenkiel, S P; Carapella, J J; Wanlass, M W

2013-02-01

Given an unknown multicomponent alloy, and a set of standard compounds or alloys of known composition, can one improve upon popular standards-based methods for energy dispersive X-ray (EDX) spectrometry to quantify the elemental composition of the unknown specimen? A method is presented here for determining elemental composition of alloys using transmission electron microscopy-based EDX with appropriate standards. The method begins with a discrete set of related reference standards of known composition, applies multivariate statistical analysis to those spectra, and evaluates the compositions with a linear matrix algebra method to relate the spectra to elemental composition. By using associated standards, only limited assumptions about the physical origins of the EDX spectra are needed. Spectral absorption corrections can be performed by providing an estimate of the foil thickness of one or more reference standards. The technique was applied to III-V multicomponent alloy thin films: composition and foil thickness were determined for various III-V alloys. The results were then validated by comparing with X-ray diffraction and photoluminescence analysis, demonstrating accuracy of approximately 1% in atomic fraction.

Multiresidue analysis of 24 Water Framework Directive priority substances by on-line solid phase extraction-liquid chromatography tandem mass spectrometry in environmental waters.

PubMed

Rubirola, Adrià; Boleda, Mª Rosa; Galceran, Mª Teresa

2017-04-14

This paper reports the development of a fully multiresidue and automated on-line solid phase extraction (SPE) - liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of 24 priority substances (PS) belonging to different classes (pesticides, hormones or pharmaceuticals) included in the Directive 2013/39/UE and the recent Watch List (Decision 2015/495) in water samples (drinking water, surface water, and effluent wastewaters). LC-MS/MS conditions and on-line SPE parameters such as sorbent type, sample and wash volumes were optimized. The developed method is highly sensitive (limits of detection between 0.1 and 1.4ngL -1 ) and precise (relative standard deviations lower than 8%). As part of the method validation studies, linearity, accuracy and matrix effects were assessed. The main advantage of this method over traditional off-line procedures is the minimization of tedious sample preparation increasing productivity and sample throughput. The optimized method was applied to the analysis of water samples and the results revealed the presence of 16 PS in river water and effluent water of wastewater treatment plants. Copyright © 2017 Elsevier B.V. All rights reserved.

A short review of applications of liquid chromatography mass spectrometry based metabolomics techniques to the analysis of human urine.

PubMed

Zhang, Tong; Watson, David G

2015-05-07

The applications of metabolomics as a methodology for providing better treatment and understanding human disease continue to expand rapidly. In this review, covering the last two years, the focus is on liquid chromatography-mass spectrometry (LC-MS) profiling of metabolites in urine. In LC-MS based metabolomics there are still problems with regard to: chromatographic separation, peak picking and alignment, metabolite identification, metabolite coverage, instrument sensitivity and data interpretation and in the case of urine sample normalisation. Progress has been made with regard to all of these issues during the period of the review. Of particular interest are the increasing use of orthogonal chromatographic methods for optimal metabolite coverage and the increasing adoption of receiver operator characteristic (ROC) curves for biomarker validation.

Profiling and Quantification of Regioisomeric Caffeoyl Glucoses in Berry Fruits.

PubMed

Patras, Maria A; Jaiswal, Rakesh; McDougall, Gordon J; Kuhnert, Nikolai

2018-02-07

On the basis of a recently developed tandem mass spectrometry-based hierarchical scheme for the identification of regioisomeric caffeoyl glucoses, selected berry fruits were profiled for their caffeoyl glucose ester content. Fresh edible berries profiled, including strawberries, raspberries, blueberries, blackberries, red currant, black currant, lingonberries, gooseberries, and juices of elderberries, goji berries, chokeberries, cranberries, açai berries, sea buckthorn berries, Montmorency sour cherries, and pomegranates, were investigated. 1-Caffeoyl glucose was found to be the predominant isomer in the majority of samples, with further profiling revealing the presence of additional hydroxycinnamoyl glucose esters and O-glycosides with p-coumaroyl, feruloyl, and sinapoyl substituents. A quantitative liquid chromatography-mass spectrometry-based method was developed and validated, and all caffeoyl glucose isomers were quantified for the first time in edible berries.

Multispectral Wavefronts Retrieval in Digital Holographic Three-Dimensional Imaging Spectrometry

NASA Astrophysics Data System (ADS)

Yoshimori, Kyu

2010-04-01

This paper deals with a recently developed passive interferometric technique for retrieving a set of spectral components of wavefronts that are propagating from a spatially incoherent, polychromatic object. The technique is based on measurement of 5-D spatial coherence function using a suitably designed interferometer. By applying signal processing, including aperture synthesis and spectral decomposition, one may obtains a set of wavefronts of different spectral bands. Since each wavefront is equivalent to the complex Fresnel hologram at a particular spectrum of the polychromatic object, application of the conventional Fresnel transform yields 3-D image of different spectrum. Thus, this technique of multispectral wavefronts retrieval provides a new type of 3-D imaging spectrometry based on a fully passive interferometry. Experimental results are also shown to demonstrate the validity of the method.

A validated inductively coupled plasma mass spectrometry (ICP-MS) method for the quantification of total platinum content in plasma, plasma ultrafiltrate, urine and peritoneal fluid.

PubMed

Lemoine, Lieselotte; Thijssen, Elsy; Noben, Jean-Paul; Adriaensens, Peter; Carleer, Robert; Speeten, Kurt Van der

2018-04-15

Oxaliplatin is a platinum (Pt) 1 containing antineoplastic agent that is applied in current clinical practice for the treatment of colon and appendiceal neoplasms. A fully validated, highly sensitive, high throughput inductively coupled plasma mass spectrometry (ICP-MS) method is provided to quantify the total Pt content in plasma, plasma ultrafiltrate, urine and peritoneal fluid. In this ICP-MS approach, the only step of sample preparation is a 1000-fold dilution in 0.5% nitric acid, allowing the analysis of 17 samples per hour. Detection of Pt was achieved over a linear range of 0.01-100 ng/mL. The limit of quantification was 18.0 ng/mL Pt in plasma, 8.0 ng/mL in ultrafiltrate and 6.1 ng/mL in urine and peritoneal fluid. The ICP-MS method was further validated for inter-and intraday precision and accuracy (≤15%), recovery, robustness and stability. Short-term storage of the biofluids, for 14 days, can be performed at -4 °C, -24 °C and -80 °C. As to long-term stability, up to 5 months, storage at -80 °C is encouraged. Furthermore, a timeline assessing the total and unbound Pt fraction in plasma and ultrafiltrate over a period of 45 h is provided. Following an incubation period of 5 h at 37 °C, 19-21% of Pt was recovered in the ultrafiltrate, emphasizing the extensive and rapid binding of oxaliplatin-derived Pt to plasma proteins. The described method can easily be implemented in a routine setting for pharmacokinetic studies in patients treated with oxaliplatin-based hyperthermic intraperitoneal perioperative chemotherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Dried Blood Spots Combined With Ultra-High-Performance Liquid Chromatography-Mass Spectrometry for the Quantification of the Antipsychotics Risperidone, Aripiprazole, Pipamperone, and Their Major Metabolites.

PubMed

Tron, Camille; Kloosterboer, Sanne M; van der Nagel, Bart C H; Wijma, Rixt A; Dierckx, Bram; Dieleman, Gwen C; van Gelder, Teun; Koch, Birgit C P

2017-08-01

Risperidone, aripiprazole, and pipamperone are antipsychotic drugs frequently prescribed for the treatment of comorbid behavioral problems in children with autism spectrum disorders. Therapeutic drug monitoring (TDM) could be useful to decrease side effects and to improve patient outcome. Dried blood spot (DBS) sample collection seems to be an attractive technique to develop TDM of these drugs in a pediatric population. The aim of this work was to develop and validate a DBS assay suitable for TDM and home sampling. Risperidone, 9-OH risperidone, aripiprazole, dehydroaripiprazole, and pipamperone were extracted from DBS and analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry using a C18 reversed-phase column with a mobile phase consisting of ammonium acetate/formic acid in water or methanol. The suitability of DBS for TDM was assessed by studying the influence of specific parameters: extraction solution, EDTA carryover, hematocrit, punching location, spot volume, and hemolysis. The assay was validated with respect to conventional guidelines for bioanalytical methods. The method was linear, specific without any critical matrix effect, and with a mean recovery around 90%. Accuracy and imprecision were within the acceptance criteria in samples with hematocrit values from 30% to 45%. EDTA or hemolysis did not skew the results, and no punching carryover was observed. No significant influence of the spot volume or the punch location was observed. The antipsychotics were all stable in DBS stored 10 days at room temperature and 1 month at 4 or -80°C. The method was successfully applied to quantify the 3 antipsychotics and their metabolites in patient samples. A UHPLC-MS/MS method has been successfully validated for the simultaneous quantification of risperidone, 9-OH risperidone, aripiprazole, dehydroaripiprazole, and pipamperone in DBS. The assay provided good analytical performances for TDM and clinical research applications.

Simultaneous determination of flurbiprofen and its hydroxy metabolite in human plasma by liquid chromatography-tandem mass spectrometry for clinical application.

PubMed

Lee, Hye-In; Choi, Chang-Ik; Byeon, Ji-Yeong; Lee, Jung-Eun; Park, So-Young; Kim, Young-Hoon; Kim, Se-Hyung; Lee, Yun-Jeong; Jang, Choon-Gon; Lee, Seok-Yong

2014-11-15

Flurbiprofen (FLB) is one of the phenylalkanoic acid derivatives of non-steroidal anti-inflammatory drugs used for the management of pain and inflammation in patients with arthritis. We developed and validated a rapid and sensitive high-performance liquid chromatography analytical method utilizing tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of FLB and its major metabolite, 4'-hydroxyflurbiprofen (4'-OH-FLB), in human plasma. Probenecid was used as an internal standard (IS). After liquid-liquid extraction with methyl t-butyl ether, chromatographic separation of the two analytes was achieved using a reversed-phase Luna C18 column (2.0mm×50mm, 5μm particles) with a mobile phase of 10mM ammonium formate buffer (pH 3.5)-methanol (15:85, v/v) and quantified by MS/MS detection in ESI negative ion mode. The flow rate of the mobile phase was 250μl/min and the retention times of FLB, 4'-OH-FLB, and IS were 1.1, 0.8, and 0.9min, respectively. The calibration curves were linear over a range of 0.01-10μg/ml for FLB and 0.01-1μg/ml for 4'-OH-FLB. The lower limit of quantifications using 100μl of human plasma was 0.01μg/ml for both analytes. The mean accuracy and precision for intra- and inter-run validation of FLB and 4'-OH-FLB were all within acceptable limits. The present HPLC-MS/MS method showed improved sensitivity for quantification of the FLB and its major metabolite in human plasma compared with previously described analytical methods. The validated method was successfully applied to a pharmacokinetic study in humans. Copyright © 2014 Elsevier B.V. All rights reserved.

Hydrogen sulfide measurement using sulfide dibimane: critical evaluation with electrospray ion trap mass spectrometry

PubMed Central

Shen, Xinggui; Chakraborty, Sourav; Dugas, Tammy R; Kevil, Christopher G

2015-01-01

Accurate measurement of hydrogen sulfide bioavailability remains a technical challenge due to numerous issues involving sample processing, detection methods used, and actual biochemical products measured. Our group and others have reported that reverse phase HPLC detection of sulfide dibimane (SDB) product from the reaction of H2S/HS− with monobromobimane allows for analytical detection of hydrogen sulfide bioavailability in free and other biochemical forms. However, it remains unclear whether possible interfering contaminants may contribute to HPLC SDB peak readings that may result in inaccurate measurements of bioavailable sulfide. In this study, we critically compared hydrogen sulfide dependent SDB detection using reverse phase HPLC (RP-HPLC) versus quantitative SRM electrospray ionization mass spectrometry (ESI/MS) to obtain greater clarity into the validity of the reverse phase HPLC method for analytical measurement of hydrogen sulfide. Using an LCQ-deca ion-trap mass spectrometer, SDB was identified by ESI/MS positive ion mode, and quantified by selected reaction monitoring (SRM) using hydrocortisone as an internal standard. Collision induced dissociation (CID) parameters were optimized at MS2 level for SDB and hydrocortisone. ESI/MS detection of SDB standard was found to be a log order more sensitive than RP-HPLC with a lower limit of 0.25 nM. Direct comparison of tissue and plasma SDB levels using RP-HPLC and ESI/MS methods revealed comparable sulfide levels in plasma, aorta, heart, lung and brain. Together, these data confirm the use of SDB as valid indicator of H2S bioavailability and highlights differences between analytical detection methods. PMID:24932544

Liquid chromatography-tandem mass spectrometry assay for the quantification of free and total sialic acid in human cerebrospinal fluid.

PubMed

van der Ham, Maria; de Koning, Tom J; Lefeber, Dirk; Fleer, André; Prinsen, Berthil H C M T; de Sain-van der Velden, Monique G M

2010-05-01

Analysis of sialic acid (SA) metabolites in cerebrospinal fluid (CSF) is important for clinical diagnosis. In the present study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS) method for free sialic acid (FSA) and total sialic acid (TSA) in human CSF was validated. The method utilized a simple sample-preparation procedure of protein precipitation for FSA and acid hydrolysis for TSA. Negative electrospray ionisation was used to monitor the transitions m/z 308.2-->87.0 (SA) and m/z 311.2--> 90.0 ((13)C(3)-SA). Conjugated sialic acid (CSA) was calculated by subtracting FSA from TSA. We established reference intervals for FSA, TSA and CSA in CSF in 217 control subjects. The method has been applied to patients' samples with known differences in SA metabolites like meningitis (n=6), brain tumour (n=2), leukaemia (n=5), and Salla disease (n=1). Limit of detection (LOD) was 0.54 microM for FSA and 0.45 mM for TSA. Intra- and inter-assay variation for FSA (21.8 microM) were 4.8% (n=10) and 10.4% (n=40) respectively. Intra- and inter-assay variation for TSA (35.6 microM) were 9.7% (n=10) and 12.8% (n=40) respectively. Tested patients showed values of TSA above established reference value. The validated method allows sensitive and specific measurement of SA metabolites in CSF and can be applied for clinical diagnoses. 2010 Elsevier B.V. All rights reserved.

Capillary electrophoresis tandem mass spectrometry determination of glutamic acid and homocysteine's metabolites: Potential biomarkers of amyotrophic lateral sclerosis.

PubMed

Cieslarova, Zuzana; Lopes, Fernando Silva; do Lago, Claudimir Lucio; França, Marcondes Cavalcante; Colnaghi Simionato, Ana Valéria

2017-08-01

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both lower and upper motor neurons, leading to muscle atrophy, paralysis, and death caused by respiratory failure or infectious complications. Altered levels of homocysteine, cysteine, methionine, and glutamic acid have been observed in plasma of ALS patients. In this context, a method for determination of these potential biomarkers in plasma by capillary electrophoresis tandem mass spectrometry (CE-MS/MS) is proposed herein. Sample preparation was carefully investigated, since sulfur-containing amino acids may interact with plasma proteins. Owing to the non-thiol sulfur atom in methionine, it was necessary to split sample preparation into two methods: i) determination of homocysteine and cysteine as S-acetyl amino acids; ii) determination of glutamic acid and methionine. All amino acids were separated within 25min by CE-MS/MS using 5molL -1 acetic acid as background electrolyte and 5mmolL -1 acetic acid in 50% methanol/H 2 O (v/v) as sheath liquid. The proposed CE-MS/MS method was validated, presenting RSD values below 6% and 11% for intra- and inter-day precision, respectively, for the middle concentration level within the linear range. The limits of detection ranged from 35 (homocysteine) to 268nmolL -1 (glutamic acid). The validated method was applied to the analysis of plasma samples from a group of healthy individuals and patients with ALS, showing the potential of glutamic acid and homocysteine metabolites as biomarkers of ALS. Copyright © 2017 Elsevier B.V. All rights reserved.

Automated solid-phase extraction-liquid chromatography-tandem mass spectrometry analysis of 6-acetylmorphine in human urine specimens: application for a high-throughput urine analysis laboratory.

PubMed

Robandt, P V; Bui, H M; Scancella, J M; Klette, K L

2010-10-01

An automated solid-phase extraction-liquid chromatography- tandem mass spectrometry (SPE-LC-MS-MS) method using the Spark Holland Symbiosis Pharma SPE-LC coupled to a Waters Quattro Micro MS-MS was developed for the analysis of 6-acetylmorphine (6-AM) in human urine specimens. The method was linear (R² = 0.9983) to 100 ng/mL, with no carryover at 200 ng/mL. Limits of quantification and detection were found to be 2 ng/mL. Interrun precision calculated as percent coefficient of variation (%CV) and evaluated by analyzing five specimens at 10 ng/mL over nine batches (n = 45) was 3.6%. Intrarun precision evaluated from 0 to 100 ng/mL ranged from 1.0 to 4.4%CV. Other opioids (codeine, morphine, oxycodone, oxymorphone, hydromorphone, hydrocodone, and norcodeine) did not interfere in the detection, quantification, or chromatography of 6-AM or the deuterated internal standard. The quantified values for 41 authentic human urine specimens previously found to contain 6-AM by a validated gas chromatography (GC)-MS method were compared to those obtained by the SPE-LC-MS-MS method. The SPE-LC-MS-MS procedure eliminates the human factors of specimen handling, extraction, and derivatization, thereby reducing labor costs and rework resulting from human error or technique issues. The time required for extraction and analysis was reduced by approximately 50% when compared to a validated 6-AM procedure using manual SPE and GC-MS analysis.

Determination of Aristolochic Acid in Botanicals and Dietary Supplements by Liquid Chromatography with Ultraviolet Detection and by Liquid Chromatography/Mass Spectrometry: Single Laboratory Validation Confirmation

PubMed Central

Trujillo, William A.; Sorenson, Wendy R.; La Luzerne, Paul; Austad, John W.; Sullivan, Darryl

2008-01-01

The presence of aristolochic acid in some dietary supplements is a concern to regulators and consumers. A method has been developed, by initially using a reference method as a guide, during single laboratory validation (SLV) for the determination of aristolochic acid I, also known as aristolochic acid A, in botanical species and dietary supplements at concentrations of approximately 2 to 32 μg/g. Higher levels were determined by dilution to fit the standard curve. Through the SLV, the method was optimized for quantification by liquid Chromatography with ultraviolet detection (LC-UV) and LC/mass Spectrometry (MS) confirmation. The test samples were extracted with organic solvent and water, then injected on a reverse phase LC column. Quantification was achieved with linear regression using a laboratory automation system. The SLV study included systematically optimizing the LC-UV method with regard to test sample size, fine grinding of solids, and solvent extraction efficiency. These parameters were varied in increments (and in separate optimization studies), in order to ensure that each parameter was individually studied; the test results include corresponding tables of parameter variations. In addition, the chromatographic conditions were optimized with respect to injection volume and detection wavelength. Precision studies produced overall relative standard deviation values from 2.44 up to 8.26% for aristolochic acid I. Mean recoveries were between 100 and 103% at the 2 μg/g level, between 102 and 103% at the 10 μg/g level, and 104% at the 30 μg/g level. PMID:16915829

Determination of aristolochic acid in botanicals and dietary supplements by liquid chromatography with ultraviolet detection and by liquid chromatography/mass spectrometry: single laboratory validation confirmation.

PubMed

Trujillo, William A; Sorenson, Wendy R; La Luzerne, Paul; Austad, John W; Sullivan, Darryl

2006-01-01

The presence of aristolochic acid in some dietary supplements is a concern to regulators and consumers. A method has been developed, by initially using a reference method as a guide, during single laboratory validation (SLV) for the determination of aristolochic acid I, also known as aristolochic acid A, in botanical species and dietary supplements at concentrations of approximately 2 to 32 microg/g. Higher levels were determined by dilution to fit the standard curve. Through the SLV, the method was optimized for quantification by liquid chromatography with ultraviolet detection (LC-UV) and LC/mass spectrometry (MS) confirmation. The test samples were extracted with organic solvent and water, then injected on a reverse phase LC column. Quantification was achieved with linear regression using a laboratory automation system. The SLV study included systematically optimizing the LC-UV method with regard to test sample size, fine grinding of solids, and solvent extraction efficiency. These parameters were varied in increments (and in separate optimization studies), in order to ensure that each parameter was individually studied; the test results include corresponding tables of parameter variations. In addition, the chromatographic conditions were optimized with respect to injection volume and detection wavelength. Precision studies produced overall relative standard deviation values from 2.44 up to 8.26% for aristolochic acid I. Mean recoveries were between 100 and 103% at the 2 microg/g level, between 102 and 103% at the 10 microg/g level, and 104% at the 30 microg/g level.

Simultaneous Determination of Celecoxib, Erlotinib, and its Metabolite Desmethyl-Erlotinib (OSI-420) in Rat Plasma by Liquid chromatography/Tandem Mass Spectrometry with Positive/Negative Ion-Switching Electrospray Ionisation

PubMed Central

Thappali, Satheeshmanikandan R. S.; Varanasi, Kanthikiran; Veeraraghavan, Sridhar; Arla, Rambabu; Chennupati, Sandhya; Rajamanickam, Madheswaran; Vakkalanka, Swaroop; Khagga, Mukkanti

2012-01-01

A new method for the simultaneous determination of celecoxib, erlotinib, and its active metabolite desmethyl-erlotinib (OSI-420) in rat plasma, by liquid chromatography/tandem mass spectrometry with positive/negative ion-switching electrospray ionization mode, was developed and validated. Protein precipitation with methanol was selected as the method for preparing the samples. The analytes were separated on a reverse-phase C18 column (50mm×4.6mm i.d., 3μ) using methanol: 2 mM ammonium acetate buffer, and pH 4.0 as the mobile phase at a flow rate 0.8 mL/min. Sitagliptin and Efervirenz were used as the internal standards for quantification. The determination was carried out on a Theremo Finnigan Quantam ultra triple-quadrupole mass spectrometer, operated in selected reaction monitoring (SRM) mode using the following transitions monitored simultaneously: positive m/z 394.5→278.1 for erlotinib, m/z 380.3→278.1 for desmethyl erlotinib (OSI-420), and negative m/z −380.1→ −316.3 for celecoxib. The limits of quantification (LOQs) were 1.5 ng/mL for Celecoxib, erlotinib, and OSI-420. Within- and between-day accuracy and precision of the validated method were within the acceptable limits of < 15% at all concentrations. The quantitation method was successfully applied for the simultaneous estimation of celecoxib, erlotinib, and desmethyl erlotinib in a pharmacokinetic study in Wistar rats. PMID:23008811

Development, validation and application of a micro-liquid chromatography-tandem mass spectrometry based method for simultaneous quantification of selected protein biomarkers of endothelial dysfunction in murine plasma.

PubMed

Suraj, Joanna; Kurpińska, Anna; Olkowicz, Mariola; Niedzielska-Andres, Ewa; Smolik, Magdalena; Zakrzewska, Agnieszka; Jasztal, Agnieszka; Sitek, Barbara; Chlopicki, Stefan; Walczak, Maria

2018-02-05

The objective of this study was to develop and validate the method based on micro-liquid chromatography-tandem mass spectrometry (microLC/MS-MRM) for simultaneous determination of adiponectin (ADN), von Willebrand factor (vWF), soluble form of vascular cell adhesion molecule 1 (sVCAM-1), soluble form of intercellular adhesion molecule 1 (sICAM-1) and syndecan-1 (SDC-1) in mouse plasma. The calibration range was established from 2.5pmol/mL to 5000pmol/mL for ADN; 5pmol/mL to 5000pmol/mL for vWF; 0.375pmol/mL to 250pmol/mL for sVCAM-1 and sICAM-1; and 0.25pmol/mL to 250pmol/mL for SDC-1. The method was applied to measure the plasma concentration of selected proteins in mice fed high-fat diet (HFD), and revealed the pro-thrombotic status by increased concentration of vWF (1.31±0.17 nmol/mL (Control) vs 1.98±0.09 nmol/mL (HFD), p <0.05) and the dysregulation of adipose tissue metabolism by decreased concentration of ADN (0.62±0.08 nmol/mL (Control) vs 0.37±0.06 nmol/mL (HFD), p <0.05). In conclusion, the microLC/MS-MRM-based method allows for reliable measurements of selected protein biomarkers of endothelial dysfunction in mouse plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

An improved LC-MS/MS method for the quantification of alverine and para hydroxy alverine in human plasma for a bioequivalence study☆.

PubMed

Rathod, Dhiraj M; Patel, Keyur R; Mistri, Hiren N; Jangid, Arvind G; Shrivastav, Pranav S; Sanyal, Mallika

2017-04-01

A highly sensitive and selective high performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of alverine (ALV) and its active metabolite, para hydroxy alverine (PHA), in human plasma. For sample preparation, solid phase extraction of analytes was performed on Phenomenex Strata-X cartridges using alverine-d5 as the internal standard. The analytes were separated on Symmetry Shield RP 18 (150 mm×3.9 mm, 5 µm) column with a mobile phase consisting of acetonitrile and 10 mM ammonium formate (65:35, v/v). Detection and quantitation was done by electrospray ionization mass spectrometry in the positive mode using multiple reaction monitoring. The assay method was fully validated over the concentration range of 15.0-15,000 pg/mL for ALV and 30.0-15,000 pg/mL for PHA. The intra-day and inter-day accuracy and precision (% CV) ranged from 94.00% to 96.00% and 0.48% to 4.15% for both the analytes. The mean recovery obtained for ALV and PHA was 80.59% and 81.26%, respectively. Matrix effect, expressed as IS-normalized matrix factor ranged from 0.982 to 1.009 for both the analytes. The application of the method was demonstrated for the specific analysis of ALV and PHA for a bioequivalence study in 52 healthy subjects using 120 mg ALV capsules. The assay reproducibility was also verified by reanalysis of 175 incurred subject samples.

Determination of triapine, a ribonucleotide reductase inhibitor, in human plasma by liquid chromatography tandem mass spectrometry.

PubMed

Feng, Ye; Kunos, Charles A; Xu, Yan

2015-09-01

Triapine is an inhibitor of ribonucleotide reductase (RNR). Studies have shown that triapine significantly decreases the activity of RNR and enhanced the radiation-mediated cytotoxicity in cervical and colon cancer. In this work, we have developed and validated a selective and sensitive LC-MS/MS method for the determination of triapine in human plasma. In this method, 2-[(3-fluoro-2-pyridinyl)methylene] hydrazinecarbothioamide (NSC 266749) was used as the internal standard (IS); plasma samples were prepared by deproteinization with acetonitrile; tripaine and the IS were separated on a Waters Xbridge Shield RP18 column (3.5 µm; 2.1 × 50 mm) using a mobile phase containing 25.0% methanol and 75.0% ammonium bicarbonate buffer (10.0 mM, pH 8.50; v/v); column eluate was monitored by positive turbo-ionspray tandem mass spectrometry; and quantitation of triapine was carried out in multiple-reaction-monitoring mode. The method developed had a linear calibration range of 0.250-50.0 ng/mL with correlation coefficient of 0.999 for triapine in human plasma. The IS-normalized recovery and the IS-normalized matrix factor of triapine were 101-104% and 0.89-1.05, respectively. The accuracy expressed as percentage error and precision expressed as coefficient of variation were ≤±6 and ≤8%, respectively. The validated LC-MS/MS method was applied to the measurement of triapine in patient samples from a phase I clinical trial. Copyright © 2015 John Wiley & Sons, Ltd.

Counting Molecules by Desorption Ionization and Mass Spectrometry/Mass Spectrometry.

ERIC Educational Resources Information Center

Cooks, R. G.; Busch, K. L.

1982-01-01

Discusses two newer methods in mass spectrometry and shows how they can increase signal and signal-to-noise ratios, respectively. The first method, desorption ionization (DI), increases sensitivity while the second method, mass spectrometry/mass spectrometry (MS/MS), increases specificity. Together, the two methods offer improved analytical…

Fast analysis of doping agents in urine by ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry. II: Confirmatory analysis.

PubMed

Badoud, F; Grata, E; Perrenoud, L; Saugy, M; Rudaz, S; Veuthey, J-L

2010-06-18

For doping control, analyses of samples are generally achieved in two steps: a rapid screening and, in the case of a positive result, a confirmatory analysis. A two-step methodology based on ultra-high-pressure liquid chromatography coupled to a quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was developed to screen and confirm 103 doping agents from various classes (e.g., beta-blockers, stimulants, diuretics, and narcotics). The screening method was presented in a previous article as part I (i.e., Fast analysis of doping agents in urine by ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry. Part I: screening analysis). For the confirmatory method, basic, neutral and acidic compounds were extracted by a dedicated solid-phase extraction (SPE) in a 96-well plate format and detected by MS in the tandem mode to obtain precursor and characteristic product ions. The mass accuracy and the elemental composition of precursor and product ions were used for compound identification. After validation including matrix effect determination, the method was considered reliable to confirm suspect results without ambiguity according to the positivity criteria established by the World Anti-Doping Agency (WADA). Moreover, an isocratic method was developed to separate ephedrine from its isomer pseudoephedrine and cathine from phenylpropanolamine in a single run, what allowed their direct quantification in urine. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Comprehensive analysis of chemical constituents in Xingxiong injection by high performance liquid chromatography coupled with mass spectrometry.

PubMed

Guo, Long; Dou, Li-Li; Duan, Li; Liu, Ke; Bi, Zhi-Ming; Li, Ping; Liu, E-Hu

2015-09-01

Xingxiong injection (XXI) is a widely used Chinese herbal formula prepared by the folium ginkgo extract and ligustrazine for the treatment of cardiovascular and cerebrovascular diseases. Compared with the pharmacological studies, chemical analysis and quality control studies on this formula are relatively limited. In the present study, a high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF MS) method was applied to comprehensive analysis of constituents in XXI. According to the fragmentation rules and previous reports, thirty ginkgo flavonoids, four ginkgo terpene lactones, and one alkaloid were identified. A high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-QQQ MS) method was then applied to quantify ten major constituents in XXI. The method validation results indicated that the developed method had desirable specificity, linearity, precision and accuracy. The total contents of ginkgo flavonoids were about 22.05-25.51 μg·mL(-1) and the ginkgo terpene lactones amounts were about 4.41-8.70 μg·mL(-1) in six batches of XXI samples, respectively. Furthermore, cosine ratio algorithm and distance measurements were employed to evaluate the similarity of XXI samples, and the results demonstrated a high-quality consistency. This work could provide comprehensive information on the quality control of Xingxiong injection, which be helpful in the establishment of a rational quality control standard. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Quantification of citalopram or escitalopram and their demethylated metabolites in neonatal hair samples by liquid chromatography-tandem mass spectrometry.

PubMed

Frison, Giampietro; Favretto, Donata; Vogliardi, Susanna; Terranova, Claudio; Ferrara, Santo Davide

2008-08-01

Citalopram and escitalopram are highly selective serotonin reuptake inhibitors widely used in the treatment of depression. They exhibit adverse drug reactions and side effects, however, and the development of specific methods for their determination is of great interest in clinical and forensic toxicology. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the assay of citalopram, escitalopram, and their demethylated metabolites in 10-mg hair samples. The analytes were extracted by incubation in methanol and liquid/liquid extraction with diethyl ether/dichloromethane. Gradient elution on a narrow bore C18 column was realized using clomipramine-d3 as an internal standard. Positive ion electrospray ionization and tandem mass spectrometry determination by collision-induced dissociation were performed in an ion trap mass spectrometer. The method exhibited a linear range of 25 to 2000 pg/mg, a quantification limit of 25 pg/mg for all analytes, relative standard deviations in the range of 12.10 to 9.80 (intraassay), and 13.80 to 11.78 (interassay), and accuracies (as percent recovery of the spiked standards) in the range of 90% to 110%; it was applied to the determination of citalopram and escitalopram and their metabolites in hair samples of two newborns to document their in utero exposure to the drugs. The method proved suitable for neonatal hair analysis of citalopram or escitalopram and was applied to two real cases of gestational exposure.

Simultaneous determination of four alkaloids in Lindera aggregata by ultra-high-pressure liquid chromatography-tandem mass spectrometry.

PubMed

Han, Zheng; Zheng, Yunliang; Chen, Na; Luan, Lianjun; Zhou, Changxin; Gan, Lishe; Wu, Yongjiang

2008-11-28

A new separation and quantification method using liquid chromatography under ultra-high-pressure in combination with tandem mass spectrometry (MS/MS) was developed for simultaneous determination of four alkaloids in Lindera aggregata. The analysis was performed on an Acquity UPLC BEH C(18) column (50mmx2.1mm, 1.7microm particle size; Waters, Milford, MA, USA) utilizing a gradient elution profile and a mobile phase consisting of (A) water containing 10mM ammonium acetate adjusted to pH 3 with acetic acid and (B) acetonitrile. An electrospray ionization (ESI)-tandem interface in the positive mode was employed prior to mass spectrometric detection. The calibration curve was linear over the range of 17.1-856ng for boldine, 42.4-2652ng for norboldine, 6.1-304ng for reticuline and 0.5-50ng for linderegatine, respectively. The average recoveries ranged from 99.2 to 101.4% with RSDs< or =2.7%. Then, four L. aggregata samples from different batches were analyzed using the established method. The results indicated that ultra-high-pressure liquid chromatography-tandem mass spectrometry provided improved chromatographic parameters resulting in significantly increased sample throughput including lower solvent consumption and lower limits of quantitation (LOQs) for most of target analytes compared to previous method employing conventional high-performance liquid chromatography (HPLC) separation. So, the established method was validated, sensitive and reliable for the determination of four alkaloids in L. aggregata.

Dereplication of plant phenolics using a mass-spectrometry database independent method.

PubMed

Borges, Ricardo M; Taujale, Rahil; de Souza, Juliana Santana; de Andrade Bezerra, Thaís; Silva, Eder Lana E; Herzog, Ronny; Ponce, Francesca V; Wolfender, Jean-Luc; Edison, Arthur S

2018-05-29

Dereplication, an approach to sidestep the efforts involved in the isolation of known compounds, is generally accepted as being the first stage of novel discoveries in natural product research. It is based on metabolite profiling analysis of complex natural extracts. To present the application of LipidXplorer for automatic targeted dereplication of phenolics in plant crude extracts based on direct infusion high-resolution tandem mass spectrometry data. LipidXplorer uses a user-defined molecular fragmentation query language (MFQL) to search for specific characteristic fragmentation patterns in large data sets and highlight the corresponding metabolites. To this end, MFQL files were written to dereplicate common phenolics occurring in plant extracts. Complementary MFQL files were used for validation purposes. New MFQL files with molecular formula restrictions for common classes of phenolic natural products were generated for the metabolite profiling of different representative crude plant extracts. This method was evaluated against an open-source software for mass-spectrometry data processing (MZMine®) and against manual annotation based on published data. The targeted LipidXplorer method implemented using common phenolic fragmentation patterns, was found to be able to annotate more phenolics than MZMine® that is based on automated queries on the available databases. Additionally, screening for ascarosides, natural products with unrelated structures to plant phenolics collected from the nematode Caenorhabditis elegans, demonstrated the specificity of this method by cross-testing both groups of chemicals in both plants and nematodes. Copyright © 2018 John Wiley & Sons, Ltd.

Ultra-trace levels analysis of microcystins and nodularin in surface water by on-line solid-phase extraction with high-performance liquid chromatography tandem mass spectrometry.

PubMed

Balest, Lydia; Murgolo, Sapia; Sciancalepore, Lucia; Montemurro, Patrizia; Abis, Pier Paolo; Pastore, Carlo; Mascolo, Giuseppe

2016-06-01

An on-line solid phase extraction coupled with high-performance liquid chromatography in tandem with mass spectrometry (on-line SPE/HPLC/MS-MS) method for the determination of five microcystins and nodularin in surface waters at submicrogram per liter concentrations has been optimized. Maximum recoveries were achieved by carefully optimizing the extraction sample volume, loading solvent, wash solvent, and pH of the sample. The developed method was also validated according to both UNI EN ISO IEC 17025 and UNICHIM guidelines. Specifically, ten analytical runs were performed at three different concentration levels using a reference mix solution containing the six analytes. The method was applied for monitoring the concentrations of microcystins and nodularin in real surface water during a sampling campaign of 9 months in which the ELISA method was used as standard official method. The results of the two methods were compared showing good agreement when the highest concentration values of MCs were found. Graphical abstract An on-line SPE/HPLC/MS-MS method for the determination of five microcystins and nodularin in surface waters at sub μg L(-1) was optimized and compared with ELISA assay method for real samples.

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. Copyright © 2016 John Wiley & Sons, Ltd.

Analytical method for the determination of various arsenic species in rice, rice food products, apple juice, and other juices by ion chromatography-inductively coupled plasma/mass spectrometry.

PubMed

Ellingson, David; Zywicki, Richard; Sullivan, Darryl

2014-01-01

Recent studies have shown that there are detectable levels of arsenic (As) in rice, rice food products, and apple juice. This has created significant concern to the public, the food industry, and various regulatory bodies. Classic test methods typically measure total As and are unable to differentiate the various As species. Since different As species have greatly different toxicities, an analytical method was needed to separate and quantify the different inorganic and organic species of As. The inorganic species arsenite [As(+3)] and arsenate [As(+5)] are highly toxic. With this in mind, an ion chromatography-inductively coupled plasma (IC-ICP/MS) method was developed and validated for rice and rice food products that can separate and individually measure multiple inorganic and organic species of As. This allows for the evaluation of the safety or risk associated with any product analyzed. The IC-ICP/MS method was validated on rice and rice food products, and it has been used successfully on apple juice. This paper provides details of the validated method as well as some lessons learned during its development. Precision and accuracy data are presented for rice, rice food products, and apple juice.

Development, validation and accreditation of a method for the determination of Pb, Cd, Cu and As in seafood and fish feed samples.

PubMed

Psoma, A K; Pasias, I N; Rousis, N I; Barkonikos, K A; Thomaidis, N S

2014-05-15

A rapid, sensitive, accurate and precise method for the determination of Pb, Cd, As and Cu in seafood and fish feed samples by Simultaneous Electrothermal Atomic Absorption Spectrometry was developed in regard to Council Directive 333/2007EC and ISO/IEC 17025 (2005). Different approaches were investigated in order to shorten the analysis time, always taking into account the sensitivity. For method validation, precision (repeatability and reproducibility) and accuracy by addition recovery tests have been assessed as performance criteria. The expanded uncertainties based on the Eurachem/Citac Guidelines were calculated. The method was accredited by the Hellenic Accreditation System and it was applied for an 8 years study in seafood (n=202) and fish feeds (n=275) from the Greek market. The annual and seasonal variation of the elemental content and correlation among the elemental content in fish feeds and the respective fish samples were also accomplished. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analysis of polymeric phenolics in red wines using different techniques combined with gel permeation chromatography fractionation.

PubMed

Guadalupe, Zenaida; Soldevilla, Alberto; Sáenz-Navajas, María-Pilar; Ayestarán, Belén

2006-04-21

A multiple-step analytical method was developed to improve the analysis of polymeric phenolics in red wines. With a common initial step based on the fractionation of wine phenolics by gel permeation chromatography (GPC), different analytical techniques were used: high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-mass spectrometry (MS), capillary zone electrophoresis (CZE) and spectrophotometry. This method proved to be valid for analyzing different families of phenolic compounds, such as monomeric phenolics and their derivatives, polymeric pigments and proanthocyanidins. The analytical characteristics of fractionation by GPC were studied and the method was fully validated, yielding satisfactory statistical results. GPC fractionation substantially improved the analysis of polymeric pigments by CZE, in terms of response, repeatability and reproducibility. It also represented an improvement in the traditional vanillin assay used for proanthocyanidin (PA) quantification. Astringent proanthocyanidins were also analyzed using a simple combined method that allowed these compounds, for which only general indexes were available, to be quantified.

Quantitative analysis of amoxicillin, its major metabolites and ampicillin in eggs by liquid chromatography combined with electrospray ionization tandem mass spectrometry.

PubMed

Sun, Lirui; Jia, Longfei; Xie, Xing; Xie, Kaizhou; Wang, Jianfeng; Liu, Jianyu; Cui, Lulu; Zhang, Genxi; Dai, Guojun; Wang, Jinyu

2016-02-01

In this present study, we developed a simple, rapid and specific method for the quantitative analysis of the contents of amoxicillin (AMO), AMO metabolites and ampicillin (AMP) in eggs. This method uses a simple liquid-liquid extraction with acetonitrile followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized method has been validated according to requirements defined by the European Union and Food and Drug Administration. Extraction recoveries of the target compounds from the egg at 5, 10 and 25 μg/kg were all higher than 80%, with relative standard deviations not exceeding 10.00%. The limits of quantification in eggs were below the maximum residue limits (MRLs). The decision limits (CCα) ranged between 11.1 and 11.5 μg/kg, while detection capabilities (CCβ) from 12.1 to 13.0 μg/kg. These values were very close to the corresponding MRLs. Finally, the new approach was successfully verified for the quantitative determination of these analytes in 40 commercial eggs from local supermarkets. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rapid screening of selective serotonin re-uptake inhibitors in urine samples using solid-phase microextraction gas chromatography-mass spectrometry.

PubMed

Salgado-Petinal, Carmen; Lamas, J Pablo; Garcia-Jares, Carmen; Llompart, Maria; Cela, Rafael

2005-07-01

In this paper a solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method is proposed for a rapid analysis of some frequently prescribed selective serotonin re-uptake inhibitors (SSRI)-venlafaxine, fluvoxamine, mirtazapine, fluoxetine, citalopram, and sertraline-in urine samples. The SPME-based method enables simultaneous determination of the target SSRI after simple in-situ derivatization of some of the target compounds. Calibration curves in water and in urine were validated and statistically compared. This revealed the absence of matrix effect and, in consequence, the possibility of quantifying SSRI in urine samples by external water calibration. Intra-day and inter-day precision was satisfactory for all the target compounds (relative standard deviation, RSD, <14%) and the detection limits achieved were <0.4 ng mL(-1) urine. The time required for the SPME step and for GC analysis (30 min each) enables high throughput. The method was applied to real urine samples from different patients being treated with some of these pharmaceuticals. Some SSRI metabolites were also detected and tentatively identified.

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

Optimization of focused ultrasonic extraction of propellant components determined by gas chromatography/mass spectrometry.

PubMed

Fryš, Ondřej; Česla, Petr; Bajerová, Petra; Adam, Martin; Ventura, Karel

2012-09-15

A method for focused ultrasonic extraction of nitroglycerin, triphenyl amine and acetyl tributyl citrate presented in double-base propellant samples following by the gas chromatography/mass spectrometry analysis was developed. A face-centered central composite design of the experiments and response surface modeling was used for optimization of the time, amplitude and sample amount. The dichloromethane was used as the extractant solvent. The optimal extraction conditions with respect to the maximum yield of the lowest abundant compound triphenyl amine were found at the 20 min extraction time, 35% amplitude of ultrasonic waves and 2.5 g of the propellant sample. The results obtained under optimal conditions were compared with the results achieved with validated Soxhlet extraction method, which is typically used for isolation and pre-concentration of compounds from the samples of explosives. The extraction yields for acetyl tributyl citrate using both extraction methods were comparable; however, the yield of ultrasonic extraction of nitroglycerin and triphenyl amine was lower than using Soxhlet extraction. The possible sources of different extraction yields are estimated and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Fast analysis of triterpenoids in Ganoderma lucidum spores by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

PubMed

Yan, Zhou; Xia, Bing; Qiu, Ming Hua; Li Sheng, Ding; Xu, Hong Xi

2013-11-01

A rapid and reliable method was established for simultaneous determination of main triterpenoids in Ganoderma lucidum spores using ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-TQ-MS). The established method was validated in terms of linearity, sensitivity, precision, accuracy and stability, and was successfully applied to determine the contents of 10 main triterpenoids in different batches of G. lucidum spores. The analysis results showed that moderate levels of triterpenoids were found in G. lucidum spores. In addition, a MS full scan with a daughter ion scan experiment was performed to identify the potential derivatives of triterpenoids present in G. lucidum spores. As a result, a total of 22 triterpenoids from different G. lucidum spores were unequivocally or tentatively identified via comparisons with authentic standards and literatures. This method provides both qualitative and quantitative results without the need for repetitive UPLC-MS analyses, thereby increasing efficiency and productivity, making it suitable for high-throughput applications. Copyright © 2013 John Wiley & Sons, Ltd.

Enrichment and determination of octylphenol and nonylphenol in environmental water samples by solid-phase microextraction with carboxylated carbon nano-spheres coating prior to gas chromatography-mass spectrometry.

PubMed

Gong, Sheng-Xiang; Wang, Xia; Li, Lei; Wang, Ming-Lin; Zhao, Ru-Song

2015-11-01

In this paper, a novel and simple method for the sensitive determination of endocrine disrupter compounds octylphenol (OP) and nonylphenol (NP) in environmental water samples has been developed using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. Carboxylated carbon nano-spheres (CNSs-COOH) are used as a novel SPME coating via physical adhesion. The CNSs-COOH fiber possessed higher adsorption efficiency than 100 μm polydimethysiloxane (PDMS) fiber and was similar to 85 μm polyacrylate (PA) fiber for the two analytes. Important parameters, such as extraction time, pH, agitation speed, ionic strength, and desorption temperature and time, were investigated and optimized in detail. Under the optimal parameters, the developed method achieved low limits of detection of 0.13~0.14 ng·L(-1) and a wide linear range of 1~1000 ng·(-1) for OP and NP. The novel method was validated with several real environmental water samples, and satisfactory results were obtained.

Determination of flubendiamide in honey at trace levels by using solid phase extraction and liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

PubMed

Ares, Ana M; Valverde, Silvia; Bernal, José L; Toribio, Laura; Nozal, María J; Bernal, José

2017-10-01

In this study, a new method has been developed to determine flubendiamide in honey using liquid chromatography coupled to a selective mass spectrometry detector (quadrupole-time-of-flight). An efficient sample treatment involving a solid phase extraction with a C 18 sorbent was proposed (average analyte recoveries were between 94 and 104%). Chromatographic analysis (9min) was performed on a C 18 column (Gemini C 18 , 50×2.0mm, 3µm, 110Å). The mobile phase consisted of water and acetonitrile, with a flow rate of 0.5mL/min in gradient elution mode. The method was fully validated in terms of selectivity, limits of detection and quantification, matrix effect, linearity, trueness and precision. Low limits of detection and quantification were obtained, ranging from 0.1 to 0.2µg/kg and 0.4 to 0.6µg/kg, respectively. The method was applied to analyze flubendiamide in honey from different botanic origins (multifloral, rosemary and heather). Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and validation of a new method to simultaneously quantify triazoles in plasma spotted on dry sample spot devices and analysed by HPLC-MS.

PubMed

Baietto, Lorena; D'Avolio, Antonio; Marra, Cristina; Simiele, Marco; Cusato, Jessica; Pace, Simone; Ariaudo, Alessandra; De Rosa, Francesco Giuseppe; Di Perri, Giovanni

2012-11-01

Therapeutic drug monitoring (TDM) of triazoles is widely used in clinical practice to optimize therapy. TDM is limited by technical problems and cost considerations, such as sample storage and dry-ice shipping. We aimed to develop and validate a new method to analyse itraconazole, posaconazole and voriconazole in plasma spotted on dry sample spot devices (DSSDs) and to quantify them by an HPLC system. Extraction from DSSDs was done using n-hexane/ethyl acetate and ammonia solution. Samples were analysed using HPLC with mass spectrometry (HPLC-MS). Accuracy and precision were assayed by inter- and intra-day validation. The stability of triazoles in plasma spotted on DSSDs was investigated at room temperature for 1 month. The method was compared with a validated standard HPLC method for quantification of triazoles in human plasma. Mean inter- and intra-day accuracy and precision were <15% for all compounds. Triazoles were stable for 2 weeks at room temperature. The method was linear (r(2) > 0.999) in the range 0.031-8 mg/L for itraconazole and posaconazole, and 0.058-15 mg/L for voriconazole. High sensitivity was observed; limits of detection were 0.008, 0.004 and 0.007 mg/L for itraconazole, posaconazole and voriconazole, respectively. A high degree of correlation (r(2) > 0.94) was obtained between the DSSD method and the standard method of analysis. The method that we developed and validated to quantify triazoles in human plasma spotted on DSSDs is accurate and precise. It overcomes problems related to plasma sample storage and shipment, allowing TDM to be performed in a cheaper and safer manner.

Measurement of neosaxitoxin in human plasma using liquid-chromatography tandem mass spectrometry: Proof of concept for a pharmacokinetic application.

PubMed

Peake, Roy W A; Zhang, Victoria Y; Azcue, Nina; Hartigan, Christina E; Shkreta, Aida; Prabhakara, Jasmina; Berde, Charles B; Kellogg, Mark D

2016-11-15

Neosaxitoxin, a member of the saxitoxin family of paralytic shellfish poisoning toxins, has shown potential as an effective, long-acting, anesthetic. We describe the development and validation of a highly sensitive method for measurement of neosaxitoxin in human plasma using liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide evidence for its use in a human pharmacokinetic study. Samples were prepared using cation exchange solid phase extraction followed by hydrophilic interaction liquid chromatography and MS/MS detection in positive electrospray ionization mode. Multiple reaction monitoring was used to monitor neosaxitoxin (m/z 316.17>220.07) and the internal standard analogue decarbamoylneosaxitoxin (m/z 273.12>180.00). The method was validated for lower limit of quantification, precision, accuracy, linearity and matrix effect. The stability of neosaxitoxin in plasma matrix at various storage conditions was also investigated. Standard curves for calibration were linear (r>0.995) across the assay calibration range, 10 to 1000pg/mL. The analytical measurable range of the assay was 10-10,000pg/mL in plasma matrix. This method has demonstrated excellent sensitivity demonstrating a lower limit of quantification in human plasma of 10pg/mL. The mean, inter-batch variation was <5.2% across the concentration range 30 to 800pg/mL. This method was successfully used in a phase 1 trial to investigate the pharmacokinetic profile of neosaxitoxin in humans following the intravenous administration of the drug at a range of doses up to 40μg. We conclude that our high-sensitivity method for measurement of neosaxitoxin in human plasma is capable of supporting future clinical trials. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of an ultra high performance liquid chromatography tandem mass spectrometry method for simultaneous determination of sulfonamides, quinolones and benzimidazoles in bovine milk.

PubMed

Hou, Xiao-Lin; Chen, Guo; Zhu, Li; Yang, Ting; Zhao, Jian; Wang, Lei; Wu, Yin-Liang

2014-07-01

A simple, sensitive and reliable analytical method was developed for the simultaneous determination of 38 veterinary drugs (18 sulfonamides, 11 quinolones and 9 benzimidazoles) and 8 metabolites of benzimidazoles in bovine milk by ultra high performance liquid chromatography-positive electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Samples were extracted with acidified acetonitrile, cleaned up with Oasis(®) MCX cartridges, and analyzed by LC-MS/MS on an Acquity UPLC(®) BEH C18 column with gradient elution. The method allows such multi-analyte measurements within a 13min runtime while the specificity is ensured through the MRM acquisition mode. The method was validated according to the European Commission Decision 2002/657/EC determining specificity, decision limit (CCα), detection capability (CCβ), recovery, precision, linearity and stability. For compounds which have MRLs in bovine milk, the CCα values fall into a range from 11 to 115μg/kg, and the CCβ values fall within a range of 12-125μg/kg. For compounds which have not MRLs in bovine milk, the CCα values fall into a range from 0.01 to 0.08μg/kg, and the CCβ values fall within a range of 0.02-0.11μg/kg. The mean recoveries of the 46 analytes were between 87 and 119%. The calculated RSD values of repeatability and within-laboratory reproducibility experiments were below 11% and 15% for the 46 compounds, respectively. The method was demonstrated to be suitable for the simultaneous determination of sulfonamides, quinolones and benzimidazoles in bovine milk. Copyright © 2014 Elsevier B.V. All rights reserved.

Liquid chromatography-tandem mass spectrometry method for determination of aliskiren in saliva and its application to a clinical trial with healthy volunteers.

PubMed

Burckhardt, Bjoern B; Tins, Jutta; Laeer, Stephanie

2014-08-05

Although serum and plasma are the biological fluids of choice for pharmacokinetic determination of drugs in adults, it is desirable to elucidate noninvasive methods which can be used for investigations in vulnerable groups such as children. If the drug properties grant sufficient penetration of the drug from blood into saliva, the latter is a useful matrix for noninvasive investigations. Concerning the known physicochemical properties, the direct renin inhibitor aliskiren is one of the substances of which saliva concentrations could substitute blood concentrations for pharmacokinetic investigations in children. Therefore, a reliable bioanalytical method was successfully developed and validated according to the criteria of current international bioanalytical guidelines to enable the comparison of blood and saliva concentrations of aliskiren. After purification of the fluid by solid-phase extraction the chromatographic separation was conducted by using Xselect™ C18 CSH columns. Applying a mobile phase gradient of acidified methanol and acidified water at a flow rate of 0.4ml/min the column effluent was monitored during a total run time of 7.5min by tandem mass spectrometry with electrospray ionization. Running in positive mode the following transitions were investigated: 552.2-436.2m/z for aliskiren and 425.3-351.2m/z for benazepril (internal standard). Calibration curves were constructed in the range of 0.586-1200ng/ml and were analyzed utilizing 1/x(2) weighted linear regression. Intra-run and inter-run precision were 3.8-8.1% and 3.4-8.9%. The method provides selectivity, linearity and accuracy. The validated method was then applied to determine aliskiren concentrations in saliva and blood of three healthy volunteers after oral administration of 300mg aliskiren. Copyright © 2014 Elsevier B.V. All rights reserved.

Multi-class analysis of new psychoactive substances and metabolites in hair by pressurized liquid extraction coupled to HPLC-HRMS.

PubMed

Montesano, Camilla; Vannutelli, Gabriele; Massa, Maristella; Simeoni, Maria Chiara; Gregori, Adolfo; Ripani, Luigi; Compagnone, Dario; Curini, Roberta; Sergi, Manuel

2017-05-01

In this paper, an analytical method has been developed and validated for the analysis of new psychoactive substances (NPS) and metabolites in hair samples. The method was based on pressurized liquid extraction (PLE) followed by solid-phase extraction (SPE) clean-up and high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) analysis. To evaluate extraction efficiency and the applicability of the method, hair samples were fortified by soaking in order to obtain a good surrogate for drug users' hair; the amount of incorporated drugs related to their lipophilicity, similarly to in vivo drug incorporation. To the best of our knowledge, this is the first method that allowed for the analysis of both cathinones (5) and synthetic cannabinoids (7) in hair with a single extraction procedure and chromatographic run. A phenethylamine (2C-T-4), 4- fluorophenylpiperazine and methoxetamine were also included showing that PLE coupled to SPE clean-up was suitable for a multi-class analysis of NPS in hair. In addition, the use of PLE significantly reduced hair analysis time: decontamination, incubation, clean-up, and liquid chromatography-mass spectrometry (LC-MS) analysis were carried out in approximately 45 min. The method was fully validated according to Scientific Working Group for Forensic Toxicology (SWGTOX) and Society of Hair Testing (SoHT) guidelines. Limit of quantification (LOQ) values ranged from 8 to 50 pg mg -1 for cathinones, phenetylamines and piperazines, and from 9 to 40 pg mg -1 for synthetic cannabinoids (10 pg mg -1 for methoxetamine). Matrix effects were below 15% for all the analytes, demonstrating the effectiveness of the clean-up step. Inaccuracy was lower than 9% in terms of bias. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Development of a gas chromatography-mass spectrometry method for the determination of pesticides in gaseous and particulate phases in the atmosphere.

PubMed

Borrás, E; Sánchez, P; Muñoz, A; Tortajada-Genaro, L A

2011-08-05

A reliable multi-residue method for determining gaseous and particulate phase pesticides in atmospheric samples has been developed. This method, based on full scan gas chromatography-mass spectrometry (GC-MS), allowed the proper determination of sixteen relevant pesticides, in a wide range of concentrations and without the influence of interferences. The pesticides were benfluralin, bitertanol, buprofezin, chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, ethalfluralin, fenthion, lindane, malathion, methidathion, propachlor, propanil, pyriproxifen, tebuconazol and trifluralin. Comparisons of two types of sampling filters (quartz and glass fibre) and four types of solid-phase cartridges (XAD-2, XAD-4, Florisil and Orbo-49P) showed that the most suitable supports were glass fibre filter for particulate pesticides and XAD-2 and XAD-4 cartridges for gaseous pesticides (>95% recovery). Evaluations of elution solvents for ultrasonic-assisted extraction demonstrated that isooctane is better than ethylacetate, dichloromethane, methanol or a mixture of acetone:hexane (1:1). Recovery assays and the standard addition method were performed to validate the proposed methodology. Moreover, large simulator chamber experiments allowed the best study of the gas-particle partitioning of pesticides for testing the sampling efficiency for the validation of an analytical multiresidue method for pesticides in air. Satisfactory analytical parameters were obtained, with a repeatability of 5±1%, a reproducibility of 13±3% and detection limits of 0.05-0.18 pg m(-3) for the particulate phase and 26-88 pg m(-3) for the gaseous phase. Finally, the methodology was successfully applied to rural and agricultural samples in the Mediterranean area. Copyright © 2011 Elsevier B.V. All rights reserved.

Enantiomeric separation and quantification of R/S-amphetamine in urine by ultra-high performance supercritical fluid chromatography tandem mass spectrometry.

PubMed

Hegstad, S; Havnen, H; Helland, A; Spigset, O; Frost, J

2018-03-01

To distinguish between legal and illegal consumption of amphetamine reliable analytical methods for chiral separation of the R- and S-enantiomers of amphetamine in biological specimens are required. In this regard, supercritical fluid chromatography (SFC) has several potential advantages over liquid chromatography, including rapid separation of enantiomers due to low viscosity and high diffusivity of supercritical carbon dioxide, the main component in the SFC mobile phase. A method for enantiomeric separation and quantification of R- and S-amphetamine in urine was developed and validated using ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS). Sample preparation prior to UHPSFC-MS/MS analysis was a semi-automatic solid phase extraction method. The UHPSFC-MS/MS method used a Chiralpak AD-3 column with a mobile phase consisting of CO 2 and 0.2% cyclohexylamine in 2-propanol. The injection volume was 2 μL and run-time was 6 min. MS/MS detection was performed with positive electrospray ionization and two multiple reaction monitoring transitions (m/z 136.1 > 119.0 and m/z 136.1 > 91.0). The calibration range was 50-10,000 ng/mL for each enantiomer. The between-assay relative standard deviations were in the range of 3.7-7.6%. Recovery was 92-93% and matrix effects ranged from 100 to 104% corrected with internal standard. After development and validation, the method has been successfully implemented in routine use at our laboratory for both separation and quantification of R/S-amphetamine, and has proved to be a reliable and useful tool for distinguishing intake of R- and S-amphetamine in authentic patient samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Development and validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of acrivastine and pseudoephedrine in human plasma and its application in pharmacokinetics.

PubMed

He, J-C; Feng, E-F; Liu, M; Li, H-L; Tian, M; Zhang, Q; Dong, L-C; Xu, G-L

2012-10-01

A specific, sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous determination of acrivastine and pseudoephedrine in human plasma samples. Plasma samples were processed and analyzed on a Phenomenex Luna 3 μ CN 100A column (150 mm×2.0 mm) eluted with the mobile phase consisting of methanol and 0.01 mol/L ammonium acetate water solution containing 0.1% formic acid (45:55, v/v) at a flow rate of 0.2 mL/min. The analytes were detected by positive ion electrospray ionization in multiple reaction monitoring mode. The transitions of m/z 349→278, m/z 166→148 and m/z 256→167 were monitored for acrivastine, pseudoephedrine and diphenhydramine (IS), respectively. The method was specific and sensitive with a lower limit of quantitation (LLOQ) of 1.52 ng/mL for acrivastine and 8.13 ng/mL for pseudoephedrine. The method showed good linearity in the range of 1.52~606.0 0 ng/mL for acrivastine and 8.13~813.12 ng/mL for pseudoephedrine (r≥0.996). The mean recovery were ranged 91.82% ~ 98.46% for acrivastine and 90.77% ~ 92.05% for pseudoephedrine. Validation results, such as accuracy, precision and repeatability were within the required limits. The method was successfully applied in a pharmacokinetic study of the acrivastine and pseudoephedrine hydrochloride compound capsule in humans. © Georg Thieme Verlag KG Stuttgart · New York.

Amnesic shellfish poisoning toxins in shellfish: estimation of uncertainty of measurement for a liquid chromatography/tandem mass spectrometry method.

PubMed

Holland, Patrick T; McNabb, Paul; Selwood, Andrew I; Neil, Tracey

2003-01-01

A liquid chromatography/mass spectrometry (LC/MS) method for amnesic shellfish poisoning toxins in shellfish was developed and validated. Tissue homogenate (4 g) was extracted with 16 mL methanol-water (1 + 1, v/v). Dilution into acetonitrile-water (1 + 9, v/v) was followed by C18 solid-phase extraction cleanup. Domoic acid (DA) and epi-domoic acid were determined by LC/MS/MS with electrospray ionization and multiple reaction monitoring. External calibration was performed with dilutions of a certified reference standard. Advantages of this method include speed, lower detection limits, and a very high degree of specificity. The LC/MS response was highly linear, and there were no significant interferences to the determination of DA. Formal method validation was performed on 4 shellfish species. Fortification studies gave recoveries (mean +/- SD; n = 24) of 93 +/- 14% at 1 mg/kg, and 93.3 +/- 7.6% at 20 mg/kg over all the species. Analysis of a mussel certified reference material showed the bias as < 5%. The limits of detection and quantitation were 0.15 and 0.5 mg/kg, respectively. Routine application of the method over 4 months gave a recovery for the QC sample (1 mg/kg fortified blank mussel homogenate) run with each batch of 88.9 +/- 5.5% (mean +/- SD; n = 37). The total uncertainty of measurement results were estimated as 0.12 (12%) at 0.25-5 mg/kg and 0.079 (7.9%) at 5-50 mg/kg. The major contribution to the uncertainty was the repeatability of the LC/MS determination, probably arising from subtle matrix effects.

Airborne environmental endotoxin: a cross-validation of sampling and analysis techniques.

PubMed Central

Walters, M; Milton, D; Larsson, L; Ford, T

1994-01-01

A standard method for measurement of airborne environmental endotoxin was developed and field tested in a fiberglass insulation-manufacturing facility. This method involved sampling with a capillary-pore membrane filter, extraction in buffer using a sonication bath, and analysis by the kinetic-Limulus assay with resistant-parallel-line estimation (KLARE). Cross-validation of the extraction and assay method was performed by comparison with methanolysis of samples followed by 3-hydroxy fatty acid (3-OHFA) analysis by gas chromatography-mass spectrometry. Direct methanolysis of filter samples and methanolysis of buffer extracts of the filters yielded similar 3-OHFA content (P = 0.72); the average difference was 2.1%. Analysis of buffer extracts for endotoxin content by the KLARE method and by gas chromatography-mass spectrometry for 3-OHFA content produced similar results (P = 0.23); the average difference was 0.88%. The source of endotoxin was gram-negative bacteria growing in recycled washwater used to clean the insulation-manufacturing equipment. The endotoxin and bacteria become airborne during spray cleaning operations. The types of 3-OHFAs in bacteria cultured from the washwater, present in the washwater and in the air, were similar. Virtually all of the bacteria cultured from air and water were gram negative composed mostly of two species, Deleya aesta and Acinetobacter johnsonii. Airborne countable bacteria correlated well with endotoxin (r2 = 0.64). Replicate sampling showed that results with the standard sampling, extraction, and Limulus assay by the KLARE method were highly reproducible (95% confidence interval for endotoxin measurement +/- 0.28 log10). These results demonstrate the accuracy, precision, and sensitivity of the standard procedure proposed for airborne environmental endotoxin. PMID:8161191

Quantitation of isocitrate dehydrogenase (IDH)-induced D and L enantiomers of 2-hydroxyglutaric acid in biological fluids by a fully validated liquid tandem mass spectrometry method, suitable for clinical applications.

PubMed

Poinsignon, Vianney; Mercier, Lionel; Nakabayashi, Koïchi; David, Muriel D; Lalli, Alexandre; Penard-Lacronique, Virginie; Quivoron, Cyril; Saada, Véronique; De Botton, Stéphane; Broutin, Sophie; Paci, Angelo

2016-06-01

A recent update of the hallmarks of cancer includes metabolism with deregulating cellular energetics. Activating mutations in isocitrate dehydrogenase (IDH) metabolic enzymes leading to the abnormal accumulation of 2-hydroxyglutaric acid (2-HGA) have been described in hematologic malignancies and solid tumours. The diagnostic value of 2-HGA levels in blood to identify IDH mutations and its prognostic significance have been reported. We developed a liquid chromatography tandem mass spectrometry method allowing a rapid, accurate and precise simultaneous quantification of both L and D enantiomers of 2-HGA in blood samples from acute myeloid leukaemia (AML) patients, suitable for clinical applications. The method was also develop for preclinical applications from cellular and tissues samples. Deuterated (R,S)-2-hydroxyglutaric acid, disodium salt was used as internal standard and added to samples before a solid phase extraction on Phenomenex STRATA™-XL-A (200mg-3mL) 33μm cartridges. A derivatization step with (+)- o,o'-diacetyl-l-tartaric anhydride permitted to separate the two resulting diastereoisomers without chiral stationary phase, on a C18 column combined to a Xevo TQ-MS Waters mass spectrometer with an electrospray ionization (ESI) source. This method allows standard curves to be linear over the range 0.34-135.04μM with r(2) values>0.999 and low matrix effects (<11.7%). This method, which was validated according to current EMA guidelines, is accurate between-run (<3.1%) and within-run (<7.9%) and precise between-run (<5.3CV%) and within-run (<6.2CV%), and is suitable for clinical and preclinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of trichloroanisole and trichlorophenol in wineries' ambient air by passive sampling and thermal desorption-gas chromatography coupled to tandem mass spectrometry.

PubMed

Camino-Sánchez, F J; Bermúdez-Peinado, R; Zafra-Gómez, A; Ruíz-García, J; Vílchez-Quero, J L

2015-02-06

The present paper describes the calibration of selected passive samplers used in the quantitation of trichlorophenol and trichloroanisole in wineries' ambient air, by calculating the corresponding sampling rates. The method is based on passive sampling with sorbent tubes and involves thermal desorption-gas chromatography-triple quadrupole mass spectrometry analysis. Three commercially available sorbents were tested using sampling cartridges with a radial design instead of axial ones. The best results were found for Tenax TA™. Sampling rates (R-values) for the selected sorbents were determined. Passive sampling was also used for accurately determining the amount of compounds present in the air. Adequate correlation coefficients between the mass of the target analytes and exposure time were obtained. The proposed validated method is a useful tool for the early detection of trichloroanisole and its precursor trichlorophenol in wineries' ambient air while avoiding contamination of wine or winery facilities. Copyright © 2015 Elsevier B.V. All rights reserved.