Science.gov

Sample records for spectrometry hplc-icp ms

  1. Application of high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for determination of chromium compounds in the air at the workplace.

    PubMed

    Stanislawska, Magdalena; Janasik, Beata; Wasowicz, Wojciech

    2013-12-15

    The toxicity and bioavailability of chromium species are highly dependable on the form or species, therefore determination of total chromium is insufficient for a complete toxicological evaluation and risk assessment. An analytical method for determination of soluble and insoluble Cr (III) and Cr (VI) compounds in welding fume at workplace air has been developed. The total chromium (Cr) was determined by using quadruple inductively coupled plasma mass spectrometry (ICP-MS) equipped with a dynamic reaction cell (DRC(®)). Soluble trivalent and hexavalent chromium compounds were determined by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). A high-speed, reversed-phase CR C8 column (PerkinElmer, Inc., Shelton, CT, USA) was used for the speciation of soluble Cr (III) and soluble Cr (VI). The separation was accomplished by interaction of the chromium species with the different components of the mobile phase. Cr (III) formed a complex with EDTA, i.e. retained on the column, while Cr (VI) existed in the solutions as dichromate. Alkaline extraction (2% KOH and 3% Na2CO3) and anion exchange column (PRP-X100, PEEK, Hamilton) were used for the separation of the total Cr (VI). The results of the determination of Cr (VI) were confirmed by the analysis of the certified reference material BCR CRM 545 (Cr (VI) in welding dust). The results obtained for the certified material (40.2±0.6 g kg(-1)) and the values recorded in the examined samples (40.7±0.6 g kg(-1)) were highly consistent. This analytical method was applied for the determination of chromium in the samples in the workplace air collected onto glass (Whatman, Ø 37 mm) and membrane filters (Sartorius, 0.8 μm, Ø 37 mm). High performance liquid chromatography with inductively coupled plasma mass spectrometry is a remarkably powerful and versatile technique for determination of chromium species in welding fume at workplace air. PMID:24209303

  2. Arsenic speciation in chinese seaweeds using HPLC-ICP-MS and HPLC-ES-MS.

    PubMed

    Van Hulle, Marijn; Zhang, Chao; Zhang, Xinrong; Cornelis, Rita

    2002-05-01

    Three common Chinese edible seaweeds, one brown (Laminaria japonica) and two red (Porphyra crispata and Eucheuma denticulatum), were examined for their total arsenic content. The As species were extracted with yields of 76.4, 69.8 and 25.0%, respectively. Anion-exchange and cation-exchange high-performance liquid chromatography (HPLC) in combination with inductively coupled plasma mass spectrometry (ICP-MS) were used for the separation of the different arsenic species in two of the three seaweed extracts (Laminaria and Porphyra). The main arsenic species in the algal extracts are arseno sugars, although it has been shown that the Laminaria seaweed contains significant amounts of dimethylarsinic acid (DMA). HPLC was coupled with electrospray mass spectrometry (ES-MS) for structural confirmation of the arsenic species. The mass spectrometer settings for the arseno sugars were optimised using standards. The conclusions drawn on the basis of HPLC-ICP-MS were confirmed by the HPLC-ES-MS data. The HPLC-ES-MS method is capable of determining both arseno sugars and DMA in the seaweeds. The unknown compounds seen in the HPLC-ICP-MS chromatogram of Laminaria could not be ascribed to trimethylarsenic oxide or tetramethylarsonium ion. PMID:12081041

  3. HPLC-ICP atomic emission spectrometry in environmental analysis

    SciTech Connect

    Frame, E.M.S.

    1996-10-01

    Trace concentrations of many compounds are difficult to determine directly by traditional chromatographic techniques. Organosilicon compounds, for example, have no chromophoric groups. Size exclusion (SEC) and high performance liquid chromatography (HPLC) can separate high and low molecular weight organosilicon compounds, but routinely employ detectors with insufficient sensitivity for trace concentrations in environmental samples. Elemental analysis methods such as inductively coupled plasma optical emission spectrometry (ICP) provide excellent element sensitivity but no speciation information. Interfacing of a chromatographic method with ICP has been shown to provide quantitative determination of trace compounds while retaining the chemical speciation information. This work will describe the power of the HPLC-ICP combination for trace compounds in environmental samples to identify and determine ppm levels of organometallics.

  4. HPLC/ICP-MS in combination with "reverse" online isotope dilution in drug metabolism studies.

    PubMed

    Meermann, Björn; Hulstaert, Anne; Laenen, Aline; Van Looveren, Cis; Vliegen, Maarten; Cuyckens, Filip; Vanhaecke, Frank

    2012-03-01

    During the development of a new drug compound, its metabolism needs to be unraveled. For quantification of the metabolites formed, the drug under investigation is traditionally synthesized with a radiolabel ((14)C or (3)H) and the metabolites present in different matrixes (blood, urine, feces) upon drug administration are determined by means of high-performance liquid chromatography (HPLC) coupled to radiodetection. This approach allows for quantification of the metabolites formed and enables a straightforward distinction between exogenous (i.e., drug-related) and endogenous species (as only the radiolabeled species are detected). However, in some cases, the use of a radiolabeled compound in human in vivo studies is not advisible, e.g., for drug compounds or their metabolites showing a long plasma or tissue half-life. In cases where the candidate drug molecule contains an element detectable by means of inductively coupled plasma mass spectrometry (ICP-MS), HPLC/ICP-MS is a promising alternative approach. However, the method lacks specificity when a distinction between drug-related species and endogenous compounds containing the same target element needs to be accomplished. As a result, we have developed an HPLC/ICP-MS-based method combined with "reverse" online isotope dilution ("reverse" online ID) for metabolite quantification. The methodology was evaluated by the analysis of feces samples from rats dosed with a (81)Br-labeled drug compound. The method allows for both (i) valid quantification of the drug metabolites and (ii) distinction among endogenous, exogenous, and "mixed" species, based on their isotopic "fingerprint". A good repeatability (relative standard deviation of 4.2%) and limit of detection (0.35 mg of drug compound L(-1) of feces extract), of the same order of magnitude as those observed for "normal" online ID HPLC/ICP-MS and HPLC/radiodetection, were achieved.

  5. Novel separation method for highly sensitive speciation of cancerostatic platinum compounds by HPLC-ICP-MS.

    PubMed

    Hann, S; Stefánka, Zs; Lenz, K; Stingeder, G

    2005-01-01

    A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method is presented for analysis of cisplatin, monoaquacisplatin, diaquacisplatin, carboplatin, and oxaliplatin in biological and environmental samples. Chromatographic separation was achieved on pentafluorophenylpropyl-functionalized silica gel. For cisplatin, carboplatin, and oxaliplatin limits of detection of 0.09, 0.10, and 0.15 microg L(-1), respectively, were calculated at m/z 194, using aqueous standard solutions. (3 microL injection volume). The method was utilized for model experiments studying the stability of carboplatin and oxaliplatin at different chloride concentrations simulating wastewater and surface water conditions. It was found that a high fraction of carboplatin is stable in ultrapure water and in solutions containing 1.5 mol L(-1) Cl-, whereas oxaliplatin degradation was increased by increasing the chloride concentration. In order to support the assessment of oxaliplatin eco-toxicology, the method was tested for speciation of patient urine. The urine sample contained more than 17 different reaction products, which demonstrates the extensive biotransformation of the compound. In a second step of the study the method was successfully evaluated for monitoring cancerostatic platinum compounds in hospital waste water.

  6. Chromium and its speciation in water samples by HPLC/ICP-MS--technique establishing metrological traceability: a review since 2000.

    PubMed

    Markiewicz, Barbara; Komorowicz, Izabela; Sajnóg, Adam; Belter, Magdalena; Barałkiewicz, Danuta

    2015-01-01

    Chromium holds a special position among living organisms because depending on its species it can be either essential or toxic. Cr(VI) even at very low concentrations is harmful and carcinogenic, while Cr(III) is a necessary microelement for cellular metabolism. Therefore, a simple analysis of Cr concentration in collected samples will not be able to distinguish these differences effectively: for a proper chemical analysis we need to perform a reliable detection and quantification of Cr species. Separation and detection of chromium can be accomplished with high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-MS) in a one-step. Our review assembles articles published since 2000 regarding chromium speciation in water samples with the use of HPLC/ICP-MS. It addresses the following issues: chromium chemistry, the possibilities of dealing with interferences, metrological aspects, analytical performance and speciated isotope dilution mass spectrometry (SIDMS) which is a definitive measurement method. The authors would like to advocate this hyphenated advanced technique as well as the metrological approach in speciation analysis of chromium.

  7. Rapid speciation and quantification of selenium compounds by HPLC-ICP MS using multiple standards labelled with different isotopes.

    PubMed

    Ohta, Yuki; Suzuki, Noriyuki; Kobayashi, Yayoi; Hirano, Seishiro

    2011-09-01

    Speciation analysis using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP MS) is now commonly used to investigate metabolic and toxicological aspects of some metals and metalloids. We have developed a rapid method for simultaneous identification and quantification of metabolites of selenium (Se) compounds using multiple standards labelled with different isotopes. A mixture of the labelled standards was spiked in a selenised garlic extract and the sample was subjected to speciation analysis by HPLC-ICP MS. The selenised garlic contains γ-glutamyl-methylselenocysteine, methylselenocysteine, and selenomethionine and the concentrations of those Se compounds were 723.8, 414.8, and 310.7 ng Se ml(-1), respectively. The isotopically labelled standards were also applied to the speciation of Se in rat urine. Selenate, methylselenonic acid, selenosugar, and trimethyselenium ions were found to be excreted by the present speciation procedure. Multiple standards labelled with different stable isotopes enable high-throughput identification and quantitative measurements of Se metabolites.

  8. Ultra-fast HPLC-ICP-MS analysis of oxaliplatin in patient urine.

    PubMed

    Koellensperger, Gunda; Hann, Stephan

    2010-05-01

    A novel method for rapid HPLC-ICP-MS analysis of oxaliplatin in human urine was developed implementing a stationary HPLC phase with a particle size of 1.8 microm. The method allowed a cycle time of <1 min at a HPLC flow rate of 0.9 mL min(-1). Procedural limits of detection of 0.05 microg L(-1) oxaliplatin (150 fg on column) were obtained. Analysis of oxaliplatin in patient urine showed that accurate quantification of the intact drug demanded for storage at -80 degrees C and rapid measurement after thawing.

  9. Application of a new HPLC-ICP-MS method for simultaneous determination of Al(3+) and aluminium fluoride complexes.

    PubMed

    Zioła-Frankowska, Anetta; Kuta, Jan; Frankowski, Marcin

    2015-10-01

    The paper presents the new HPLC-ICP-MS method used for conducting speciation analysis of aluminum as free Al(3+) and aluminum fluoride complexes during one analysis. In the study, 5% HNO3 was used as a derivative reagent in order to minimize the possibility of clogging the torch in ICP-MS. Using the new HPLC-ICP-MS method, speciation analysis of aluminum and aluminum fluoride complexes was conducted on the basis of model solutions and real samples (soil-water extracts and groundwater samples). The analysis in the presented analytical system lasts only 4 min. PMID:27441221

  10. Speciation analysis of antimony in extracts of size-classified volcanic ash by HPLC-ICP-MS.

    PubMed

    Miravet, R; López-Sánchez, J F; Rubio, R; Smichowski, P; Polla, G

    2007-03-01

    Although there is concern about the presence of toxic elements and their species in environmental matrices, for example water, sediment, and soil, speciation analysis of volcanic ash has received little attention. Antimony, in particular, an emerging element of environmental concern, has been less studied than other potentially toxic trace elements. In this context, a study was undertaken to assess the presence of inorganic Sb species in ash emitted from the Copahue volcano (Argentina). Antimony species were extracted from size-classified volcanic ash (<36 microm, 35-45 microm, 45-150 microm, and 150-300 microm) by use of 1 mol L(-1) citrate buffer at pH 5. Antimony(III) and (V) in the extracts were separated and quantified by high-performance liquid chromatography combined on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Antimony species concentrations (microg g(-1)) in the four fractions varied from 0.14 to 0.67 for Sb(III) and from 0.02 to 0.03 for Sb(V). The results reveal, for the first time, the occurrence of both inorganic Sb species in the extractable portion of volcanic ash. Sb(III) was always the predominant species.

  11. Use of the bromine isotope ratio in HPLC-ICP-MS and HPLC-ESI-MS analysis of a new drug in development.

    PubMed

    Cuyckens, Filip; Balcaen, Lieve I L; De Wolf, Kenny; De Samber, Bjorn; Van Looveren, Cis; Hurkmans, Rob; Vanhaecke, Frank

    2008-04-01

    A combination of inductively coupled plasma mass spectrometry (ICP-MS) and electrospray ionization mass spectrometry (ESI-MS) was deployed for the metabolite profiling and metabolite identification of a new antituberculosis compound (R207910, also known as TMC207) that is currently in drug development. R207910 contains one bromine atom, allowing the detection by ICP-MS. Fluctuations in the Br sensitivity caused by the HPLC gradient were counteracted by the use of species-unspecific isotope dilution. In order to evaluate the method developed, the results obtained were compared with those acquired via radioactivity detection. HPLC-ESI-MS was used for the structural identification of R207910 and its metabolites. The (79)Br/(81)Br isotope ratio is also valuable in the search for metabolites in the complex background of endogenous compounds obtained using HPLC-ESI-MS analyses. Data-dependent scanning using isotope recognition with an ion trap mass spectrometer or processing of Q-Tof data provides HPLC-ICP-MS-like "bromatograms". The combination of accurate mass measurements and the fragmentation behavior in the MS(2) spectra obtained using the Q-Tof Ultima mass spectrometer or MS(n) spectra acquired using the LTQ-Orbitrap allowed structural characterization of the main metabolites of R207910 in methanolic dog and rat faeces extracts taken 0-24 h post-dose.

  12. Absolute quantification of transferrin in blood samples of harbour seals using HPLC-ICP-MS.

    PubMed

    Grebe, Mechthild; Pröfrock, Daniel; Kakuschke, Antje; Broekaert, Jose A C; Prange, Andreas

    2011-02-01

    Harbour seals (Phoca vitulina) are bio-indicators for the assessment of their habitat and environmental changes. Besides population parameters and trends (survival, age structure, sex ratio), the individual health status represents a further important parameter for this assessment. The health status of seals is a complex and vague term, determined by a wide range of diagnostic parameters. Quantities of important blood proteins such as transferrin (Tf), as well as altered distribution patterns of its glycoforms, are frequently used as biomarkers in clinical diagnosis. Within this context Tf quantities and a varying pattern of its glycoforms are used as indicator for e.g. certain liver diseases, which also represents one of the most frequently observed pathological indication in harbour seals of the North Sea. Currently, most assay based quantification methods for Tf are limited since they often provide only information regarding the total Tf concentration rather than information of its different glycoforms. Due to a lack of suitable seal Tf antibodies also the application of more specific antibody based approaches is not possible. Within this background a new approach for the absolute quantification of the iron-transport protein Tf in the blood of harbour seals using its characteristic iron content and HPLC-ICP-MS detection is described. Method validation was performed using a certified human serum reference material (ERM-DA470K/IFCC). A Tf concentration of 2.33 ± 0.03 g L(-1) (sum of all quantified glycoforms) has been calculated, which is in good agreement with the certified total Tf concentration of 2.35 ± 0.08 g L(-1), confirming the accuracy of the proposed analytical method. Finally, different seal samples were analysed to demonstrate the suitability of the procedure for the quantification of Tf in real samples as well as to observe modified glycoform patterns. Compared to our previous studies for the first time it was possible to quantify the serum Tf

  13. Arsenic speciation in environmental waters by a new specific phosphine modified polymer microsphere preconcentration and HPLC-ICP-MS determination.

    PubMed

    Jia, Xiaoyu; Gong, Dirong; Wang, Jiani; Huang, Fuyi; Duan, Taicheng; Zhang, Xian

    2016-11-01

    A new specific phosphine modified polymer microsphere (PPMs) was designed and used as the core adsorbent to comprehensively enrich both inorganic and organic arsenic species in environmental waters by on line solid-phase extraction (SPE). Avoiding any redox reagent, all the four arsenic species have been quantitatively retained on the home made mini-column with large number of positively charged adsorption groups, and then eluted rapidly (within seconds) with a mixed solution of ammonium nitrate and ammonium dihydrogen phosphate. The trace separation and determination of As(III), DMA, MMA and As(V) species have been simultaneously achieved by high performance liquid chromatography hyphenated to inductively coupled plasma spectrometry (HPLC-ICP-MS) technique. This work has developed a versatile tri-n-butylphosphine functionalized polymer microsphere for an efficient and reliable on-line of simultaneous preconcentration and detection of inorganic and organic arsenic speciation. Under the optimized experimental conditions, the enrichment factors obtained for As(III) and DMA with 25mL sample solution were 28, while for MMA and As(V) reached 30. The low detection limits of 1.2ngL(-1), 0.96ngL(-1), 0.82ngL(-1) and 0.91ngL(-1), with the relative standard deviations (RSDs) of 3.9%, 5.6%, 3.2% and 4.5% were obtained for As(III), DMA, MMA and As(V), respectively. The developed method was validated by analyzing Certified Reference Materials GSBZ 07-3171-2014, promising for routine monitoring of arsenic species in lake water, river water and seawater samples. PMID:27591635

  14. Simultaneous determination of organotin pesticides by HPLC-ICP-MS and their sorption, desorption, and transformation in freshwater sediments.

    PubMed

    Gui, Wenjun; Tian, Chunxia; Sun, Qianqian; Li, Shuying; Zhang, Wei; Tang, Jun; Zhu, Guonian

    2016-05-15

    In order to better assess their environmental risks, the sorption and degradation of triphenyltin hydroxide, azocyclotin and fenbutatin oxide were studied in two sediments under varying laboratory conditions in this study. An analytical method for simultaneous determination of the three organotins in environmental samples was firstly developed using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). The limit of detection and limit of quantification for standards ranged from 0.13 to 1.46 μg/L. Fortification study showed that when spiked at 2-250 μg/kg the mass recoveries were 73.7-119.6%. Sorption isotherm experiments indicated that the organotins could be strongly adsorbed by the sediments, and organotin sorption kinetics obeyed the pseudo second-order kinetic model. The sorption affinity was inversely related to their water solubility. All isotherms fitted with the Henry mode fairly well (r(2) > 0.96) with distribution coefficients (Kd) ranging from 746.1 to 2465.2 mL/g. The three organotins could rapidly move from the upper water layer to the lower sediment layer, and they were all of moderate degradation compounds with the degradation half lives varying from 38.3 to 84.5d in anaerobic and aerobic water-sediment systems. The degradation rate seemed to be positively related to organic matter content of sediment. Result inferred that the three organotins had the low risks to pollute groundwater when applied on dry land and could moderately degrade in water-sediment system. However, more attention should still be paid to these organotins due to the wide application on agricultural field. PMID:26994697

  15. Selenium speciation analysis of Misgurnus anguillicaudatus selenoprotein by HPLC-ICP-MS and HPLC-ESI-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analytical methods for selenium (Se) speciation were developed using high performance liquid chromatography (HPLC) coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionization tandem mass spectrometry (ESI-MS/MS). Separations of selenomethionine (Se-Met) and sel...

  16. Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

    PubMed

    Ščančar, Janez; Berlinger, Balázs; Thomassen, Yngvar; Milačič, Radmila

    2015-09-01

    A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% water to 100% 0.7 M NaCl was applied for chromatographic separation of metal species. In standard aqueous solution at neutral pH molybdate, tungstate and vanadate exist in several aqueous species, while chromate is present as a single CrO4(2-) species. Consequently, only chromate can be separated from this solution in a sharp chromatographic peak. For obtaining sharp chromatographic peaks for molybdate, tungstate and vanadate, the pH of aqueous standard solutions was raised to 12. At highly alkaline conditions single CrO4(2-), MoO4(2-) and WO4(2-) are present and were eluted in sharp chromatographic peaks, while VO4(3-) species, which predominates at pH 12 was eluted in slightly broaden peak. In a mixture of aqueous standard solutions (pH 12) chromate, molybdate, tungstate and vanadate were eluted at retention times from 380 to 420 s, 320 to 370 s, 300 to 350 s and 240 to 360 s, respectively. Eluted species were simultaneously detected on-line by ICP-MS recording m/z 52, 95, 182 and 51. The developed procedure was successfully applied to the analysis of leachable concentrations of chromate, molybdate, tungstate and vanadate in alkaline extracts (2% NaOH+3% Na2CO3) of manual metal arc (MMA) welding fumes loaded on filters. Good repeatability and reproducibility of measurement (RSD±3.0%) for the investigated species were obtained in both aqueous standard solutions (pH 12) and in alkaline extracts of welding fumes. Low limits of detection (LODs) were found for chromate (0.02 ng Cr mL(-1)), molybdate (0.1 ng Mo mL(-1)), tungstate (0.1 ng W mL(-1)) and vanadate (0.2 ng V mL(-1)). The accuracy of analytical procedure for the determination of chromate was checked by analysis of

  17. Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

    PubMed

    Ščančar, Janez; Berlinger, Balázs; Thomassen, Yngvar; Milačič, Radmila

    2015-09-01

    A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% water to 100% 0.7 M NaCl was applied for chromatographic separation of metal species. In standard aqueous solution at neutral pH molybdate, tungstate and vanadate exist in several aqueous species, while chromate is present as a single CrO4(2-) species. Consequently, only chromate can be separated from this solution in a sharp chromatographic peak. For obtaining sharp chromatographic peaks for molybdate, tungstate and vanadate, the pH of aqueous standard solutions was raised to 12. At highly alkaline conditions single CrO4(2-), MoO4(2-) and WO4(2-) are present and were eluted in sharp chromatographic peaks, while VO4(3-) species, which predominates at pH 12 was eluted in slightly broaden peak. In a mixture of aqueous standard solutions (pH 12) chromate, molybdate, tungstate and vanadate were eluted at retention times from 380 to 420 s, 320 to 370 s, 300 to 350 s and 240 to 360 s, respectively. Eluted species were simultaneously detected on-line by ICP-MS recording m/z 52, 95, 182 and 51. The developed procedure was successfully applied to the analysis of leachable concentrations of chromate, molybdate, tungstate and vanadate in alkaline extracts (2% NaOH+3% Na2CO3) of manual metal arc (MMA) welding fumes loaded on filters. Good repeatability and reproducibility of measurement (RSD±3.0%) for the investigated species were obtained in both aqueous standard solutions (pH 12) and in alkaline extracts of welding fumes. Low limits of detection (LODs) were found for chromate (0.02 ng Cr mL(-1)), molybdate (0.1 ng Mo mL(-1)), tungstate (0.1 ng W mL(-1)) and vanadate (0.2 ng V mL(-1)). The accuracy of analytical procedure for the determination of chromate was checked by analysis of

  18. Development of a mild mercaptoethanol extraction method for determination of mercury species in biological samples by HPLC-ICP-MS.

    PubMed

    Wang, Meng; Feng, Weiyue; Shi, Junwen; Zhang, Fang; Wang, Bing; Zhu, Motao; Li, Bai; Zhao, Yuliang; Chai, Zhifang

    2007-03-30

    A mild, efficient and convenient extraction method of using 2-mercaptoethanol contained extractant solution combined with an incubator shaker for determination of mercury species in biological samples by HPLC-ICP-MS has been developed. The effects of the concentration of 2-mercaptoethanol, the composition of the extractant solution and the shaking time on the efficiency of mercury extraction were evaluated. The optimization experiments indicated that the quantitative extraction of mercury species from biological samples could be achieved by using 0.1% (v/v) HCl, 0.1% (v/v) 2-mercapoethanol and 0.15% (m/v) KCl extractant solution in an incubator shaker for shaking overnight (about 12h) at room temperature. The established method was validated by analysis of various biological certified reference materials, including NRCC DOLT-3 (dogfish liver), IAEA 436 (tuna fish), IAEA MA-B-3/TM (garfish filet), IAEA MA-M-2/TM (mussel tissue), GBW 08193 (bovine liver) and GBW 08572 (prawn). The analytical results of the reference materials were in good agreement with the certified or reference values of both methyl and total mercury, indicating that no distinguishable transformation between mercury species had occurred during the extraction and determination procedures. The limit of detection (LOD) for methyl (CH(3)Hg(+)) and inorganic mercury (Hg(2+)) by the method are both as 0.2microg L(-1). The relative standard deviation (R.S.D.s) for CH(3)Hg(+) and Hg(2+) are 3.0% and 5.8%, respectively. The advantages of the developed extraction method are that (1) it is easy to operate in HPLC-ICP-MS for mercury species determination since the extracted solution can be directly injected into the HPLC column without pH adjustment and (2) the memory effect of mercury in the ICP-MS measurement system can be reduced.

  19. Improving metallomics information related to transgenic and non-transgenic soybean seeds using 2D-HPLC-ICP-MS and ESI-MS/MS.

    PubMed

    Mataveli, Lidiane Raquel Verola; Fioramonte, Mariana; Gozzo, Fabio César; Arruda, Marco Aurélio Zezzi

    2012-04-01

    This work reports the use of 2D-HPLC-ICP-MS to enlarge metallomics information when considering soybean seeds. Separations using size exclusion chromatography (SEC) allowed the identification of three metal fractions: the first corresponding to molecular weights from 38.1 to 181.1 kDa, the second from 8.2 to 17.2 kDa and the third from 0.4 to 3.8 kDa. In a second dimension, using anion exchange chromatography (AEX), three sub-fractions containing Fe, Mg and Mn, one containing Cu, and three containing Co, Cu, Mg, Mn and Zn were obtained. After these separations, 33 proteins were identified using the ESI-MS/MS technique, and divided into four functional categories: plant growth/cell division, protein destination and storage, metabolism and unclassified proteins. Among the identified proteins, proteins previously related to metals were found.

  20. Speciation of small molecules and inorganic ions in salmon egg cell cytoplasm by surfactant-mediated HPLC/ICP-MS.

    PubMed

    Matsuura, Hirotaka; Hasegawa, Takuya; Nagata, Hitomi; Takatani, Kohei; Asano, Motoki; Itoh, Akihide; Haraguchi, Hiroki

    2003-01-01

    The speciation of diverse elements in salmon egg cell cytoplasm was performed by a surfactant-mediated HPLC/ICP-MS hyphenated system. In the present experiment, an ODS column coated with CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate), which is a zwitterionic bile acid derivative, was employed as a surfactant-mediated separation column, and ICP-MS was used as an element-selective detector. The present surfactant-mediated HPLC allowed us to separate large and small molecules within 10 min; large molecules, such as proteins, were eluted within 2.5 min, while small molecules were eluted after 2.5 min, but within 10 min. In the present experiment, Fe, Cu, and Zn in egg cell cytoplasm were observed mostly in species with large molecular weights, indicating that these elements are contained as metalloproteins or metalloenzymes in egg cell cytoplasm. On the contrary, it was found that P, S, Mo, and halogens in egg cell cytoplasm were contained as small molecules or inorganic ions. The major species of P in egg cell cytoplasm was identified as the phosphate ion (PO4(3-)). Molybdenum, Cl, and Br in egg cell cytoplasm were molybdate (MoO4(2-), chloride (Cl-), and bromide (Br-) ions, respectively.

  1. Simultaneous Speciation of Arsenic, Selenium, and Chromium by HPLC-ICP-MS

    USGS Publications Warehouse

    Wolf, Ruth E.; Morman, Suzette A.; Morrison, Jean M.; Lamothe, Paul J.

    2008-01-01

    An adaptation of an analytical method developed for chromium speciation has been utilized for the simultaneous determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) species using high performance liquid chromatography (HPLC) separation with ICP-MS detection. Reduction of interferences for the determination of As, Se, and Cr by ICP-MS is a major consideration for this method. Toward this end, a Dynamic Reaction Cell (DRC) ICP-MS system was used to detect the species eluted from the chromatographic column. A variety of reaction cell gases and conditions may be utilized, and the advantages and limitations of the gases tested to date will be presented and discussed. The separation and detection of the As, Se, and Cr species of interest can be achieved using the same chromatographic conditions in less than 2 minutes by complexing the Cr(III) with EDTA prior to injection on the HPLC column. Practical aspects of simultaneous speciation analysis will be presented and discussed, including issues with HPLC sample vial contamination, standard and sample contamination, species stability, and considerations regarding sample collection and preservation methods. The results of testing to determine the method's robustness to common concomitant element and anion effects will also be discussed. Finally, results will be presented using the method for the analysis of a variety of environmental and geological samples including waters, soil leachates and simulated bio-fluid leachates.

  2. Speciation analysis of bromine-containing drug metabolites in feces samples from a human in vivo study by means of HPLC/ICP-MS combined with on-line isotope dilution.

    PubMed

    Meermann, Björn; Bockx, Marc; Laenen, Aline; Van Looveren, Cis; Cuyckens, Filip; Vanhaecke, Frank

    2012-01-01

    The aim of this work was speciation analysis of metabolites in feces samples collected within a clinical study during which a bromine-containing anti-tuberculosis drug (TMC207) was administered to patients with multi-drug resistant tuberculosis infection. Owing to slow elimination of the drug, no (14)C label was used within this study. Quantification of the bromine species was accomplished using high performance liquid chromatography coupled to inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) in combination with on-line isotope dilution (on-line ID), while structural elucidation of the species was performed using HPLC coupled to electrospray ionization-mass spectrometry. The ICP-MS-based method developed shows a good intra- and inter-day reproducibility (relative standard deviation = 3.5%, N = 9); the limit of detection (1.5 mg TMC207 L(-1)) is of the same order of magnitude as that for HPLC/radiodetection; the dynamic range of the method covers more than two orders of magnitude. Furthermore, the column recovery was demonstrated to be quantitative (recoveries between 90.6% and 99.5%). Based on the excellent figures of merit, the "cold" HPLC/ICP-MS approach could be deployed for the actual human in vivo metabolism study, such that exposure of the human volunteers to the (14)C radiolabel was avoided.

  3. Evaluation of selenium species in selenium-enriched pakchoi (Brassica chinensis Jusl var parachinensis (Bailey) Tsen & Lee) using mixed ion-pair reversed phase HPLC-ICP-MS.

    PubMed

    Thosaikham, Witphon; Jitmanee, Kritsana; Sittipout, Rossukon; Maneetong, Sarunya; Chantiratikul, Anut; Chantiratikul, Piyanete

    2014-02-15

    HPLC-ICP-MS based on ion-paired reversed phase chromatography for the selenium speciation using the mixture of 1-butanesulfonic acid (BA) and trifluoroacetic acid (TFA) as the mixed ion-pairing reagents was developed and applied to selenium-enriched pakchoi (Brassica chinensis Jusl var parachinensis (Bailey) Tsen & Lee). Several conditions of ion-paired reversed phase HPLC-ICP-MS, such as pH of the mobile phase, concentration of ion pairing reagents, types and length of analytical column, and flow rate of the mobile phase, were optimised for five selenium species; selenate (Se(VI)), Selenite (se(IV)), selenocysteine (SeC), Se-methylselenocysteine (SeMC) and selenomethionine (SeM). The results showed that the optimum conditions for pH, BA and TFA condition, type of separating column and flow rate, were 4.5, 8mM, 4mM, C18 (250 mm length × 4.6mm I.D) and 1.2 mL min(-1), respectively. These conditions archived separation of the organic selenium species. The limits of detection (LOD) and quantitation (LOQ) of each selenium species were lower than 5 and 16 ng Se mL(-1), respectively. Furthermore, the recoveries of most selenium species were good, except for SeC. In this research, selenium-enriched pakchoi was cultivated by supplementing inorganic selenium from selenate into sand. The result showed that inorganic selenium, SeMC, SeM and several unknown species were found in selenium-enriched pakchoi sprouts by using the proposed method. Thereby, the biotransformation of selenate in pakchoi was similar to other Brassicaceae plants such as kale and broccoli.

  4. Exploring the in vitro formation of trimethylarsine sulfide from dimethylthioarsinic acid in anaerobic microflora of mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS

    SciTech Connect

    Kubachka, Kevin M.; Kohan, Michael C.; Herbin-Davis, Karen; Creed, John T. Thomas, David J.

    2009-09-01

    Although metabolism of arsenicals to form methylated oxoarsenical species has been extensively studied, less is known about the formation of thiolated arsenical species that have recently been detected as urinary metabolites. Indeed, their presence suggests that the metabolism of ingested arsenic is more complex than previously thought. Recent reports have shown that thiolated arsenicals can be produced by the anaerobic microflora of the mouse cecum, suggesting that metabolism prior to systemic absorption may be a significant determinant of the pattern and extent of exposure to various arsenic-containing species. Here, we examined the metabolism of {sup 34}S labeled dimethylthioarsinic acid ({sup 34}S-DMTA{sup V}) by the anaerobic microflora of the mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS/MS to monitor for the presence of various oxo- and thioarsenicals. The use of isotopically enriched {sup 34}S-DMTA{sup V} made it possible to differentiate among potential metabolic pathways for production of the trimethylarsine sulfide (TMAS{sup V}). Upon in vitro incubation in an assay containing anaerobic microflora of mouse cecum, {sup 34}S-DMTA{sup V} underwent several transformations. Labile {sup 34}S was exchanged with more abundant {sup 32}S to produce {sup 32}S-DMTA{sup V}, a thiol group was added to yield DMDTA{sup V}, and a methyl group was added to yield {sup 34}S-TMAS{sup V}. Because incubation of {sup 34}S-DMTA{sup V} resulted in the formation of {sup 34}S-TMAS{sup V}, the pathway for its formation must preserve the arsenic-sulfur bond. The alternative metabolic pathway postulated for formation of TMAS{sup V} from dimethylarsinic acid (DMA{sup V}) would proceed via a dimethylarsinous acid (DMA{sup III}) intermediate and would necessitate the loss of {sup 34}S label. Structural confirmation of the metabolic product was achieved using HPLC-ESI-MS/MS. The data presented support the direct methylation of DMTA{sup V} to TMAS{sup V}. Additionally, the detection of

  5. Exploring the in vitro formation of trimethylarsine sulfide from dimethylthioarsinic acid in anaerobic microflora of mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS.

    PubMed

    Kubachka, Kevin M; Kohan, Michael C; Herbin-Davis, Karen; Creed, John T; Thomas, David J

    2009-09-01

    Although metabolism of arsenicals to form methylated oxoarsenical species has been extensively studied, less is known about the formation of thiolated arsenical species that have recently been detected as urinary metabolites. Indeed, their presence suggests that the metabolism of ingested arsenic is more complex than previously thought. Recent reports have shown that thiolated arsenicals can be produced by the anaerobic microflora of the mouse cecum, suggesting that metabolism prior to systemic absorption may be a significant determinant of the pattern and extent of exposure to various arsenic-containing species. Here, we examined the metabolism of 34S labeled dimethylthioarsinic acid (34S-DMTA(V)) by the anaerobic microflora of the mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS/MS to monitor for the presence of various oxo- and thioarsenicals. The use of isotopically enriched 34S-DMTA(V) made it possible to differentiate among potential metabolic pathways for production of the trimethylarsine sulfide (TMAS(V)). Upon in vitro incubation in an assay containing anaerobic microflora of mouse cecum, 34S-DMTA(V) underwent several transformations. Labile 34S was exchanged with more abundant 32S to produce 32S-DMTA(V), a thiol group was added to yield DMDTA(V), and a methyl group was added to yield 34S-TMAS(V). Because incubation of 34S-DMTA(V) resulted in the formation of 34S-TMAS(V), the pathway for its formation must preserve the arsenic-sulfur bond. The alternative metabolic pathway postulated for formation of TMAS(V) from dimethylarsinic acid (DMA(V)) would proceed via a dimethylarsinous acid (DMA(III)) intermediate and would necessitate the loss of 34S label. Structural confirmation of the metabolic product was achieved using HPLC-ESI-MS/MS. The data presented support the direct methylation of DMTA(V) to TMAS(V). Additionally, the detection of isotopically pure 34S-TMAS(V) raises questions about the sulfur exchange properties of TMAS(V) in the cecum material

  6. Ribonucleoside labeling with Os(VI): a methodological approach to evaluation of RNA methylation by HPLC-ICP-MS.

    PubMed

    Wrobel, Katarzyna; Rodríguez Flores, Crescencio; Chan, Qilin; Wrobel, Kazimierz

    2010-02-01

    Covalent modifications of nucleobases are thought to play an important role in regulating the functions of DNA and various cellular RNA types. Perhaps the best characterized is DNA methylation on cytosine (methyl tag attached to carbon 5 position) and such modification has also been detected in stable and long-lived RNA molecules. In this work, we propose a novel procedure enabling very sensitive quantification of methylcytidine and other ribonucleosides, based on reversed phase liquid chromatography with inductively coupled plasma mass spectrometry (ICP-MS) detection. The procedure relies on labeling ribose residues with osmium, by formation of a ternary complex between cis-diol ribose groups, hexavalent osmium (K(2)OsO(2)(OH)(4)) and tetramethylethylenediamine (TEMED). The derivatization reaction was carried out with 50 : 1 molar excess of Os to ribonucleoside, pH 4, for 2 h at room temperature. The structures of Os-labeled cytidine and methylcytidine were confirmed by electrospray ionization mass spectrometry. The separation of Os-labeled cytidine (C), uridine (U), 5-methylcytidine (5mC) and guanosine (G) was achieved on C18 column (Gemini, 150 × 3 mm, 5 μm) with isocratic elution (0.05% triethylamine + 6 mmol L(-1) ammonium acetate, pH 4.4: methanol (85 : 15)) and a total flow rate 0.6 mL min(-1). The column effluent was on-line introduced to ICP-MS (a model 7500 ce, Agilent Technologies) for specific detection at (189)Os. Calibration was performed within the concentration range 0-200 nmol L(-1) of each ribonucleoside and the analytical figures of merit were evaluated. For 100 μL injection, the detection limits for C, U, 5mC, G were 24, 38, 21 and 28 pmol L(-1), respectively. While introducing Os(vi)-TEMED to the column, it eluted in the dead volume and the detection limit for osmium was 20 pmol L(-1). The results obtained in this work might be helpful in the analysis of RNA digests, providing quantitative data on the ribonucleoside composition and

  7. Combined use of HPLC-ICP-MS and microwave-assisted extraction for the determination of cobalt compounds in nutritive supplements.

    PubMed

    Yang, Fang-Yu; Jiang, Shiuh-Jen; Sahayam, A C

    2014-03-15

    Speciation analysis of cobalt in nutritive supplements has been carried out using HPLC and ICP-MS equipped with a membrane desolvation sample introduction system as detector. In this study, cobalt containing compounds, namely Co(II), cyanocobalamin (CN-Cbl) and hydroxylcobalamin (OH-Cbl), were well separated by reversed phase HPLC with a C8-HPLC column as the stationary phase and 8 mmol L(-1) ammonium acetate in 22%v/v methanol solution (pH 4) as the mobile phase using isocratic elution. Detection limit was in the range of 0.008-0.014 μg CoL(-1) for various Co species. Over 98% of the total cobalt species was extracted in nutritive supplements using a 0.5%v/v HNO3 solution in a microwave field; and the spike recovery was in the range of 92-108% for various species. The HPLC-ICP-MS results showed a satisfactory agreement with the total cobalt concentrations obtained by ICP-MS analysis of completely dissolved samples.

  8. Development of analytical procedures for determination of total chromium by quadrupole ICP-MS and high-resolution ICP-MS, and hexavalent chromium by HPLC-ICP-MS, in different materials used in the automotive industry.

    PubMed

    Séby, F; Gagean, M; Garraud, H; Castetbon, A; Donard, O F X

    2003-10-01

    A European directive was recently adopted limiting the use of hazardous substances such as Pb, Hg, Cd, and Cr(VI) in vehicle manufacturing. From July 2003 a maximum of 2 g Cr(VI) will be authorised per vehicle in corrosion-preventing coatings of key components. As no standardised procedures are available to check if produced vehicles are in agreement with this directive, the objective of this work was to develop analytical procedures for total chromium and Cr(VI) determination in these materials. The first step of this study was to optimise digestion procedures for total chromium determination in plastic and metallic materials by inductively coupled plasma mass spectrometry (ICP-MS). High resolution (HR) ICP-MS was used to examine the influence of polyatomic interferences on the detection of the (52)Cr(+) and (53)Cr(+) isotopes. If there was strong interference with m/ z 52 for plastic materials, it was possible to use quadrupole ICP-MS for m/ z 53 if digestions were performed with HNO(3)+H(2)O(2). This mixture was also necessary for digestion of chromium from metallic materials. Extraction procedures in alkaline medium (NH(4)(+)/NH(3) buffer solution at pH 8.9) assisted by sonication were developed for determining Cr(VI) in four different corrosion-preventing coatings by HPLC-ICP-MS. After optimisation and validation with the only solid reference material certified for its Cr(VI) content (BCR 545; welding dusts), the efficiency of this extraction procedure for screw coatings was compared with that described in the EN ISO 3613 standard generally used in routine laboratories. For coatings comprising zinc and aluminium passivated in depth with chromium oxides the extraction procedure developed herein enabled determination of higher Cr(VI) concentrations. This was also observed for the screw covered with a chromium passivant layer on zinc-nickel. For coating comprising a chromium passivant layer on alkaline zinc the standardized extraction procedure was more efficient

  9. Determination of arsenic species in rice from Thailand and other Asian countries using simple extraction and HPLC-ICP-MS analysis.

    PubMed

    Nookabkaew, Sumontha; Rangkadilok, Nuchanart; Mahidol, Chulabhorn; Promsuk, Gunlatida; Satayavivad, Jutamaad

    2013-07-17

    Human exposure to arsenic (As) via rice consumption is of increasing concern. In the present study, the extraction and HPLC-ICP-MS analysis for As speciation in rice were investigated. A simple extraction with water and digestion with α-amylase followed by the analysis using ion-paring mode HPLC separation was developed. The method showed good extraction efficiencies (generally >80%) and column efficiencies (>90%) for rice samples. The optimization of mobile phase showed well separated peaks of As species. The limits of quantification (LOQ) of As(III), As(V), MMA, and DMA that were calculated based on sample mass were 1.6, 2.0, 2.0, and 1.6 μg kg(-1), respectively. A total of 185 rice samples (various types of rice) collected from different four regions in Thailand and some other Asian countries were analyzed. The total As and inorganic As in rice samples were in the ranges of 22.51-375.39 and 13.89-232.62 μg kg(-1), respectively. The estimated weekly intake of inorganic As from rice by Thai people accounted for 13.91-29.22% of the provisional tolerable weekly intake (PTWI).

  10. Speciation analysis of selenium in plankton, Brazil nut and human urine samples by HPLC-ICP-MS.

    PubMed

    da Silva, Elidiane Gomes; Mataveli, Lidiane Raquel Verola; Arruda, Marco Aurélio Zezzi

    2013-06-15

    The HPLC (anion exchange)-ICP-MS technique was used for the identification (based on retention time of standards) and determination of four selenium species (selenite, selenate, selenomethionine and selenocystine) in plankton (BCR-414), Brazil nuts and urine samples. A recovery of 91% was attained for certified reference materials (BCR-414). Se(IV) was the predominant species in plankton, with the highest selenium concentration in the extract. The Brazil nuts showed only the organic species selenomethionine and selenocystine after water extraction, but after simulated gastrointestinal digestion, only selenomethionine was found as bioaccessible, corresponding to 74% of the total selenium (54.8±4.6 μg g(-1)). Analyses of the urine samples suggested the presence of selenocystine, and significant differences were observed between samples from men and women in terms of the concentration of this species after consumption of Brazil nuts (1 nut per day during 15 days).

  11. Antimony, Arsenic and Chromium Speciation Studies in Biała Przemsza River (Upper Silesia, Poland) Water by HPLC-ICP-MS

    PubMed Central

    Jabłońska-Czapla, Magdalena

    2015-01-01

    In this paper the total concentration of As, Cr, Sb, pH and the red-ox potential of water and sediment samples of the Biała Przemsza River were determined. The arsenic (AB, MMA, DMA, As(III), As(V)), chromium (Cr(III), Cr(VI)) and antimony (Sb(III), Sb(V)) forms were studied by HPLC-ICP-MS. Ions were successfully separated on Hamilton PRP-X100: (AB, MMA, DMA, As(III), As(V)), Dionex Ion Pac AS-7 (Sb(III), Sb(V)) and Dionex IonPac AG7 columns: Cr(III), Cr(VI) with LOD 0.16 μg/L, 0.08 μg/L, 0.09 μg/L, 0.012 μg/L, 0.08 μg/L, 0.12 μg/L, 0.009 μg/L, 0.012 μg/L, 0.19 μg/L, 0.37 μg/L, respectively. The simplified BCR three-step sequential chemical extraction was performed on the bottom sediment samples. The samples were collected monthly, between April and December 2014, at five sampling points. Large contents of manganese, lead, cadmium and zinc were found in the Biała Przemsza River water. In December 2014, the lead content in the bottom sediment in Sławków was nearly 6000 mg/kg. In the river water, only the inorganic arsenic speciation forms were found. Sb(V), As(V) and Cr(III) were dominant. Studies have shown that arsenic, antimony and chromium were mainly bound to oxides, organic matter and sulphides in the bottom sediments. PMID:25941843

  12. Antimony, Arsenic and Chromium Speciation Studies in Biała Przemsza River (Upper Silesia, Poland) Water by HPLC-ICP-MS.

    PubMed

    Jabłońska-Czapla, Magdalena

    2015-04-30

    In this paper the total concentration of As, Cr, Sb, pH and the red-ox potential of water and sediment samples of the Biała Przemsza River were determined. The arsenic (AB, MMA, DMA, As(III), As(V)), chromium (Cr(III), Cr(VI)) and antimony (Sb(III), Sb(V)) forms were studied by HPLC-ICP-MS. Ions were successfully separated on Hamilton PRP-X100: (AB, MMA, DMA, As(III), As(V)), Dionex Ion Pac AS-7 (Sb(III), Sb(V)) and Dionex IonPac AG7 columns: Cr(III), Cr(VI) with LOD 0.16 μg/L, 0.08 μg/L, 0.09 μg/L, 0.012 μg/L, 0.08 μg/L, 0.12 μg/L, 0.009 μg/L, 0.012 μg/L, 0.19 μg/L, 0.37 μg/L, respectively. The simplified BCR three-step sequential chemical extraction was performed on the bottom sediment samples. The samples were collected monthly, between April and December 2014, at five sampling points. Large contents of manganese, lead, cadmium and zinc were found in the Biała Przemsza River water. In December 2014, the lead content in the bottom sediment in Sławków was nearly 6000 mg/kg. In the river water, only the inorganic arsenic speciation forms were found. Sb(V), As(V) and Cr(III) were dominant. Studies have shown that arsenic, antimony and chromium were mainly bound to oxides, organic matter and sulphides in the bottom sediments.

  13. An HPLC-ICP-MS technique for determination of cadmium-phytochelatins in genetically modified Arabidopsis thaliana.

    PubMed

    Sadi, Baki B M; Vonderheide, Anne P; Gong, Ji-Ming; Schroeder, Julian I; Shann, Jodi R; Caruso, Joseph A

    2008-01-01

    A reversed-phase high-performance liquid chromatographic technique was developed to separate cadmium-phytochelatin complexes (Cd-PC2, Cd-PC3, and Cd-PC4) of interest in the plant Arapidopsis thaliana. High-performance liquid chromatography (HPLC) was coupled to an inductively coupled plasma mass spectrometric (ICP-MS) system with some modification to the interface. This was done in order to sustain the plasma with optimum sensitivity for cadmium detection in the presence of the high methanol loads used in the gradient elution of the reversed-phase separation. The detection limits were found to be 91.8 ngl(-1), 77.2 ngl(-1) and 49.2 ngl(-1) for Cd-PC2, Cd-PC3, and Cd-PC4 respectively. The regression coefficients (r2) for Cd-PC2 to Cd-PC4 detection ranged from 0.998 to 0.999. The method was then used to investigate the occurrence and effect of cadmium-phytochelatin complexes in wild-type Arabidopsis and a phytochelatin-deficient mutant cad1-3 that had been genetically modified to ectopically express the wheat TaPCS1 phytochelatin synthase enzyme. The primary complex found in both wild-type and transgenic plants was Cd-PC2. In both lines, higher levels of Cd-PC2 were found in shoots than in roots, showing that phytochelatin synthases contribute to the accumulation of cadmium in shoots, in the Cd-PC2 form. Genetic modification did, however, impact the overall accumulation of Cd. Transgenic plants contained almost two times more cadmium in the form of Cd-PC2 in their roots than did the corresponding wild-type plants. Similarly, the shoot samples of the modified species also contained more (by 1.6 times) cadmium in the form of Cd-PC2 than the wild type. The enhanced role of PC2 in the transgenic Arabidopsis correlates with data showing long-distance transport of Cd in transgenic plants. Targeted transgenic expression of non-native phytochelatin synthases may contribute to improving the efficiency of plants for phytoremediation. PMID:18065298

  14. An HPLC-ICP-MS technique for determination of cadmium-phytochelatins in genetically modified Arabidopsis thaliana.

    PubMed

    Sadi, Baki B M; Vonderheide, Anne P; Gong, Ji-Ming; Schroeder, Julian I; Shann, Jodi R; Caruso, Joseph A

    2008-01-01

    A reversed-phase high-performance liquid chromatographic technique was developed to separate cadmium-phytochelatin complexes (Cd-PC2, Cd-PC3, and Cd-PC4) of interest in the plant Arapidopsis thaliana. High-performance liquid chromatography (HPLC) was coupled to an inductively coupled plasma mass spectrometric (ICP-MS) system with some modification to the interface. This was done in order to sustain the plasma with optimum sensitivity for cadmium detection in the presence of the high methanol loads used in the gradient elution of the reversed-phase separation. The detection limits were found to be 91.8 ngl(-1), 77.2 ngl(-1) and 49.2 ngl(-1) for Cd-PC2, Cd-PC3, and Cd-PC4 respectively. The regression coefficients (r2) for Cd-PC2 to Cd-PC4 detection ranged from 0.998 to 0.999. The method was then used to investigate the occurrence and effect of cadmium-phytochelatin complexes in wild-type Arabidopsis and a phytochelatin-deficient mutant cad1-3 that had been genetically modified to ectopically express the wheat TaPCS1 phytochelatin synthase enzyme. The primary complex found in both wild-type and transgenic plants was Cd-PC2. In both lines, higher levels of Cd-PC2 were found in shoots than in roots, showing that phytochelatin synthases contribute to the accumulation of cadmium in shoots, in the Cd-PC2 form. Genetic modification did, however, impact the overall accumulation of Cd. Transgenic plants contained almost two times more cadmium in the form of Cd-PC2 in their roots than did the corresponding wild-type plants. Similarly, the shoot samples of the modified species also contained more (by 1.6 times) cadmium in the form of Cd-PC2 than the wild type. The enhanced role of PC2 in the transgenic Arabidopsis correlates with data showing long-distance transport of Cd in transgenic plants. Targeted transgenic expression of non-native phytochelatin synthases may contribute to improving the efficiency of plants for phytoremediation.

  15. An HPLC-ICP-MS technique for determination of cadmium–phytochelatins in genetically modified Arabidopsis thaliana

    PubMed Central

    Sadi, Baki B.M.; Vonderheide, Anne P.; Gong, Ji-Ming; Schroeder, Julian I.; Shann, Jodi R.; Caruso, Joseph A.

    2010-01-01

    A reversed-phase high-performance liquid chromatographic technique was developed to separate cadmium–phytochelatin complexes (Cd-PC2, Cd-PC3, and Cd-PC4) of interest in the plant Arapidopsis thaliana. High-performance liquid chromatography (HPLC) was coupled to an inductively coupled plasma mass spectrometric (ICP-MS) system with some modification to the interface. This was done in order to sustain the plasma with optimum sensitivity for cadmium detection in the presence of the high methanol loads used in the gradient elution of the reversed-phase separation. The detection limits were found to be 91.8 ng l−1, 77.2 ng l−1 and 49.2 ng l−1 for Cd-PC2, Cd-PC3, and Cd-PC4 respectively. The regression coefficients (r2) for Cd-PC2 to Cd-PC4 detection ranged from 0.998 to 0.999. The method was then used to investigate the occurrence and effect of cadmium–phytochelatin complexes in wild-type Arabidopsis and a phytochelatin-deficient mutant cad1-3 that had been genetically modified to ectopically express the wheat TaPCS1 phytochelatin synthase enzyme. The primary complex found in both wild-type and transgenic plants was Cd-PC2. In both lines, higher levels of Cd-PC2 were found in shoots than in roots, showing that phytochelatin synthases contribute to the accumulation of cadmium in shoots, in the Cd-PC2 form. Genetic modification did, however, impact the overall accumulation of Cd. Transgenic plants contained almost two times more cadmium in the form of Cd-PC2 in their roots than did the corresponding wild-type plants. Similarly, the shoot samples of the modified species also contained more (by 1.6 times) cadmium in the form of Cd-PC2 than the wild type. The enhanced role of PC2 in the transgenic Arabidopsis correlates with data showing long-distance transport of Cd in transgenic plants. Targeted transgenic expression of non-native phytochelatin synthases may contribute to improving the efficiency of plants for phytoremediation. PMID:18065298

  16. Study on multielemental speciation analysis of Cr(VI), As(III) and As(V) in water by advanced hyphenated technique HPLC/ICP-DRC-MS. Fast and reliable procedures.

    PubMed

    Marcinkowska, Monika; Komorowicz, Izabela; Barałkiewicz, Danuta

    2015-11-01

    Analytical procedures for multielemental speciation analysis of arsenite - As(III), arsenate - As(V) and hexavalent chromium - Cr(VI) in water using high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC/ICP-DRC-MS) hyphenated technique have been developed. A dynamic reaction cell (DRC) for spectral interferences elimination has been involved in the experiment. Application of oxygen and ammonia as reaction gases in the DRC under various conditions has been verified. Optimization of the following chromatographic conditions: mobile phase composition, concentration of particular components, mobile phase pH and flow rate, injection volume and column temperature, has been conducted. Species separation has been carried out on anion-exchange chromatographic column using isocratic elution with: 22 mM (NH4)2HPO4, 25 mM NH4NO3 (for procedure A) and 22 mM (NH4)2HPO4, 65 mM NH4NO3 (for procedure B) as mobile phases. Detection limits (LD) for procedure A were 0.16 µg L(-1), 0.090 µg L(-1), 0.073 µg L(-1), and for procedure B were 0.14 µg L(-1), 0.062 µg L(-1), 0.15 µg L(-1) for As(III), As(V) and Cr(VI), respectively. Linearity was tested at two concentration ranges of: (0.5-10.0) µg L(-1) for procedure A and (5-50) µg L(-1) for procedure B, and showed correlation coefficients for each of the analytes to be above 0.999. Repeatability values obtained for spiked real water samples were in the range of (4.2-7.6)% and (2.0-2.4)% for procedure A and B respectively. Accuracy was calculated based on the analysis of spiked real water samples at three concentration levels. Obtained recoveries were from 94% to 102%. PMID:26452815

  17. New procedure for multielemental speciation analysis of five toxic species: As(III), As(V), Cr(VI), Sb(III) and Sb(V) in drinking water samples by advanced hyphenated technique HPLC/ICP-DRC-MS.

    PubMed

    Marcinkowska, Monika; Komorowicz, Izabela; Barałkiewicz, Danuta

    2016-05-12

    Analytical procedure dedicated for multielemental determination of toxic species: As(III), As(V), Cr(VI), Sb(III) and Sb(V) in drinking water samples using high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-DRC-MS) technique was developed. Optimization of the detection and separation conditions was conducted. Dynamic reaction cell (DRC) with oxygen as a reaction gas was involved in the experiments. Obtained analytical signals for species separation were symmetrical, as studied by anion-exchange chromatography. Applied mobile phase consisted of 3 mM of EDTANa2 and 36 mM of ammonium nitrate. Full separation of species in the form of the following forms: H3AsO3, H2AsO4(-), SbO2(-), Sb(OH)6(-), CrO4(2-) was achieved in 15 min with use of gradient elution program. Detailed validation of analytical procedure proved the reliability of analytical measurements. The procedure was characterized by high precision in the range from 1.7% to 2.4%. Detection limits (LD) were 0.067 μg L(-1), 0.068 μg L(-1), 0.098 μg L(-1), 0.083 μg L(-1) and 0.038 μg L(-1) for As(III), As(V), Cr(VI), Sb(III) and Sb(V), respectively. Obtained recoveries confirmed the lack of interferences' influence on analytical signals as their values were in the range of 91%-110%. The applicability of the proposed procedure was tested on drinking water samples characterized by mineralization up to 650 mg L(-1). PMID:27114229

  18. Determination of cadmium and lead species and phytochelatins in pea (Pisum sativum) by HPLC-ICP-MS and HPLC-ESI-MSn.

    PubMed

    Barałkiewicz, Danuta; Kózka, Małgorzata; Piechalak, Aneta; Tomaszewska, Barbara; Sobczak, Paweł

    2009-07-15

    An analytical approach based on hyphenated techniques was used for studying the speciation of cadmium and lead in Pisum sativum. Proper preservation conditions were employed to avoid the oxidation of -SH groups and corresponding decomposition of metal-binding complexes. SEC column was washed with 5 mM beta-mercaptoethanol and then samples were analysed using ICP-MS as a detector. Results showed that cadmium is the inhibitor of lead uptake. HPLC-ESI-MS(n) assays revealed fragmentation pathways of phytochelatins. PMID:19559910

  19. Determination of cadmium and lead species and phytochelatins in pea (Pisum sativum) by HPLC-ICP-MS and HPLC-ESI-MSn.

    PubMed

    Barałkiewicz, Danuta; Kózka, Małgorzata; Piechalak, Aneta; Tomaszewska, Barbara; Sobczak, Paweł

    2009-07-15

    An analytical approach based on hyphenated techniques was used for studying the speciation of cadmium and lead in Pisum sativum. Proper preservation conditions were employed to avoid the oxidation of -SH groups and corresponding decomposition of metal-binding complexes. SEC column was washed with 5 mM beta-mercaptoethanol and then samples were analysed using ICP-MS as a detector. Results showed that cadmium is the inhibitor of lead uptake. HPLC-ESI-MS(n) assays revealed fragmentation pathways of phytochelatins.

  20. A study of Cu turnover in proteins of the visceral complex of Littorina littorea by stable isotopic analysis using coupled HPLC-ICP-MS.

    PubMed

    Mason, A Z; Borja, M R

    2002-01-01

    A two-dimensional HPLC system, tandemly coupled to an ICP-MS, has been used to study copper accumulation and turnover in the visceral complex cytosol of the gastropod, Littorina littorea. Animals were exposed for 8 weeks to NTA-buffered seawater containing stable isotopic 65Cu and then transferred to media containing stable isotopic 63Cu. The free ion activity of each isotope was maintained at 10(-11) M. Size exclusion (SE) HPLC showed Cu associated with haemocyanin (HC) and metallothionein-like (MT) proteins in two ligand pools with apparent molecular weights of >300 kDa and approximately 17 kDa, respectively. The MT pool was inducible by Cu, could assimilate the metal from both intrinsic and extrinsic sources and showed a higher rate of Cu accumulation and turnover than the HC pool. The induction of this pool also caused the sequestration and cytosolic redistribution of Zn, Cd, Pb, Mn and Co. Further fractionation of the MT pool by ion-exchange (IE) HPLC revealed that the Cu was associated with a single, major isoform of the protein that was Cu inducible and also bound trace quantities of Zn and Pb. A number of additional metal containing proteins were also resolved by IE. the most prominent of which also bound Pb, Mn and minor quantities of Zn. The significance of these findings in metal homeostasis and detoxification is discussed. PMID:12408587

  1. Accurate quantification of total chromium and its speciation form Cr(VI) in water by ICP-DRC-IDMS and HPLC/ICP-DRC-IDMS.

    PubMed

    Markiewicz, Barbara; Komorowicz, Izabela; Barałkiewicz, Danuta

    2016-05-15

    Two analytical procedures have been developed for the determination of total chromium (TCr) and its highly toxic species, i.e. Cr(VI) in water samples using the following methods: inductively coupled plasma dynamic reaction cell isotope dilution mass spectrometry (ICP-DRC-IDMS) and high performance liquid chromatography inductively coupled plasma dynamic reaction cell isotope dilution mass spectrometry (HPLC/ICP-DRC-IDMS). Spectral interferences, predominantly occurring in chromium determination, were removed using a dynamic reaction cell (DRC). The presented procedures facilitate the quantification of trace amounts - below 1 µg L(-1) of TCr and individual Cr species - in various water matrices including drinking water and still bottled water with different mineral composition. Special attention has been paid to the adequate preparation of isotopically enriched (53)Cr(VI) standard solution in order to avoid artifacts in chromium speciation. Both procedures were fully validated as well as establishing the traceability and estimation of the uncertainty of measurement were carried out. Application of all of the above mentioned elements and of the isotope dilution technique, which provides the highest quality of metrological traceability, allowed to obtain reliable and high quality results of chromium determination in water samples. Additionally, the comparison of two methods: HPLC/ICP-DRC-MS and HPLC/ICP-DRC-IDMS for Cr(VI) determination, was submitted basing on the validation parameters. As a result, the lower values for these parameters were obtained using the second method. PMID:26992546

  2. HPLC-ICP/MS Analysis of Thyroid Hormone and Related Iodinated Compounds in Tissues and Media

    EPA Science Inventory

    Quantifying thyroid hormone (TH) and the synthetic precursors and metabolic products of TH is important for developing models of the hypothalamic-pituitary-thyroid (HPT) axis as well as for understanding the effects of xenobiotics on HPT axis function. In this study, the developm...

  3. Fast Determination of Toxic Arsenic Species in Food Samples Using Narrow-bore High-Performance Liquid-Chromatography Inductively Coupled Plasma Mass Spectrometry.

    PubMed

    Terol, Amanda; Marcinkowska, Monika; Ardini, Francisco; Grotti, Marco

    2016-01-01

    A new method for the speciation analysis of arsenic in food using narrow-bore high-performance liquid-chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been developed. Fast separation of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid was carried out in 7 min using an anion-exchange narrow-bore Nucleosil 100 SB column and 12 mM ammonium dihydrogen phosphate of pH 5.2 as the mobile phase, at a flow rate of 0.3 mL min(-1). A PFA-ST micronebulizer jointed to a cyclonic spray chamber was used for HPLC-ICP-MS coupling. Compared with standard-bore HPLC-ICP-MS, the new method has provided higher sensitivity, reduced mobile-phase consumption, a lower matrix plasma load and a shorter analysis time. The achieved instrumental limits of detection were in the 0.3 - 0.4 ng As mL(-1) range, and the precision was better than 3%. The arsenic compounds were efficiently (>80%) extracted from various food samples using a 1:5 methanol/water solution, with additional ultrasonic treatment for rice products. The applicability of this method was demonstrated by the analysis of several samples, such as seafood (fish, mussels, shrimps, edible algae) and rice-based products (Jasmine and Arborio rice, spaghetti, flour, crackers), including three certified reference materials. PMID:27506720

  4. Electrospray Ionization Tandem Mass Spectrometry (ESI-MS/MS)-Based Shotgun Lipidomics

    SciTech Connect

    Mezengie, Giorgis I.

    2011-01-11

    In the past decade, many new strategies for mass spectrometry (MS)-based analyses of lipids have been developed. Lipidomics is one of the most promising research fields to emerge as a result of these advances in MS. Currently, mass spectrometric analysis of lipids involves two complementary approaches: direct infusion (shotgun lipidomics) and liquid chromatography coupled to MS. In this chapter, I will demonstrate the approach of shotgun lipidomics using electrospray ionization tandem MS for the analysis of lipid molecular species directly from crude biological extracts of tissue or fluids.

  5. Arsenic speciation in soil using high performance liquid chromatography/inductively coupled plasma/mass spectrometry

    SciTech Connect

    Bass, D.A.; Yaeger, J.S.; Parish, K.J.; Crain, J.S.; Kiely, J.T.; Gowdy, M.J.; Mohrman, G.B.; Besmer, M.G.

    1996-08-01

    A method has been developed to identify and quantify As(III), As(V), and organoarsenic compounds in soil samples from the Rocky Mountain Arsenal (RMA) by high performance liquid chromatography/inductively coupled plasma/mass spectrometry (HPLC/ICP/MS). The soils were extracted using tetrabutylammonium hydroxide (TBAH) and sonication. The percentages of As(III), As(V), and organoarsenic species extracted from soil samples were 30, 50, and 100 respectively. The arsenic species were not altered during the extraction process. They were separated by reversed-phase, ion-pairing, HPLC using a microbore Inertsil-ODS{trademark} column. The HPLC column effluent was introduced into an ICP/MS system using a direct injection nebulizer (DIN). Detection limits of less than 1 pg were readily obtained for each arsenic species. Internal standards are recommended to increase accuracy and precision. Soil samples spiked with arsenic oxide, sodium arsenate, dimethylarsinic acid (DMAA), and chlorovinyl arsenious acid (CVAA) were extracted, identified and quantified with the HPLC/ICP/MS system. The soil samples were analyzed in support of the analytical needs of a thermal desorption treatability study being conducted at the RMA.

  6. Simultaneous speciation of selenium and sulfur species in selenized odorless garlic (Allium sativum L. Shiro) and shallot (Allium ascalonicum) by HPLC-inductively coupled plasma-(octopole reaction system)-mass spectrometry and electrospray ionization-tandem mass spectrometry.

    PubMed

    Ogra, Yasumitsu; Ishiwata, Kazuya; Iwashita, Yuji; Suzuki, Kazuo T

    2005-11-01

    The simultaneous speciation of selenium and sulfur in selenized odorless garlic (Allium sativum L. Shiro) and a weakly odorous Allium plant, shallot (Allium ascalonicum), was performed by means of a hyphenated technique, a HPLC coupled with an inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) equipped with an octopole reaction system (ORS). The aqueous extracts of them contained the common seleno compound that was identified as gamma-glutamylmethylselenocysteine by an electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Normal garlic contains alliin as the major sulfur-containing compound, which is the biological precursor of the garlic odorant, allicin. Alliin, however, was not detected in the extracts of the selenized odorless garlic. At least, four unidentified sulfur-containing compounds were detected in odorless garlic and shallot. Moreover, these Allium plants showed chemopreventive effects against human leukemia cells.

  7. Speciation of Selenium in Selenium-Enriched Sunflower Oil by High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry/Electrospray-Orbitrap Tandem Mass Spectrometry.

    PubMed

    Bierla, Katarzyna; Flis-Borsuk, Anna; Suchocki, Piotr; Szpunar, Joanna; Lobinski, Ryszard

    2016-06-22

    The reaction of sunflower oil with selenite produces a complex mixture of selenitriglycerides with antioxidant and anticancer properties. To obtain insight into the identity and characteristics of the species formed, an analytical approach based on the combination of high-performance liquid chromatography (HPLC) with (78)Se-specific selenium detection by inductively coupled plasma mass spectrometry (ICP MS) and high-resolution (100 000), high mass accuracy (<1 ppm) molecule-specific detection by electrospray-Orbitrap MS(3) was developed. For the first time, a non-aqueous mobile phase gradient was used in reversed-phase HPLC-ICP MS for the separation of a complex mixture of selenospecies and a mathematical correction of the background signal was developed. The identical chromatographic conditions served for the sample introduction into electrospray MS. Two types of samples were analyzed: sunflower oil dissolved in isopropanol and methanol extract of the oil containing 65% selenium. HPLC-ICP MS showed 14 peaks, 11 of which could also be detected in the methanol extract. Isotopic patterns corresponding to molecules with one or two selenium atoms could be attributed by Orbitrap MS at the retention times corresponding to the HPLC-ICP MS peak apexes. Structural data for these species were acquired by MS(2) and MS(3) fragmentation of protonated or sodiated ions using high-energy collisional dissociation (HCD). A total of 11 selenium-containing triglycerol derivatives resulting from the oxidation of one or two double bonds of linoleic acid and analogous derivatives of glycerol-mixed linoleate(s)/oleinate(s) have been identified for the first time. The presence of these species was confirmed by the targeted analysis in the total oil isopropanol solution. Their identification corroborated the predicted elution order in reversed-phase chromatography: LLL (glycerol trilinoleate), LLO (glycerol dilinoleate-oleinate), LOO (glycerol linoleate-dioleinate), OOO (glycerol

  8. Speciation of Selenium in Selenium-Enriched Sunflower Oil by High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry/Electrospray-Orbitrap Tandem Mass Spectrometry.

    PubMed

    Bierla, Katarzyna; Flis-Borsuk, Anna; Suchocki, Piotr; Szpunar, Joanna; Lobinski, Ryszard

    2016-06-22

    The reaction of sunflower oil with selenite produces a complex mixture of selenitriglycerides with antioxidant and anticancer properties. To obtain insight into the identity and characteristics of the species formed, an analytical approach based on the combination of high-performance liquid chromatography (HPLC) with (78)Se-specific selenium detection by inductively coupled plasma mass spectrometry (ICP MS) and high-resolution (100 000), high mass accuracy (<1 ppm) molecule-specific detection by electrospray-Orbitrap MS(3) was developed. For the first time, a non-aqueous mobile phase gradient was used in reversed-phase HPLC-ICP MS for the separation of a complex mixture of selenospecies and a mathematical correction of the background signal was developed. The identical chromatographic conditions served for the sample introduction into electrospray MS. Two types of samples were analyzed: sunflower oil dissolved in isopropanol and methanol extract of the oil containing 65% selenium. HPLC-ICP MS showed 14 peaks, 11 of which could also be detected in the methanol extract. Isotopic patterns corresponding to molecules with one or two selenium atoms could be attributed by Orbitrap MS at the retention times corresponding to the HPLC-ICP MS peak apexes. Structural data for these species were acquired by MS(2) and MS(3) fragmentation of protonated or sodiated ions using high-energy collisional dissociation (HCD). A total of 11 selenium-containing triglycerol derivatives resulting from the oxidation of one or two double bonds of linoleic acid and analogous derivatives of glycerol-mixed linoleate(s)/oleinate(s) have been identified for the first time. The presence of these species was confirmed by the targeted analysis in the total oil isopropanol solution. Their identification corroborated the predicted elution order in reversed-phase chromatography: LLL (glycerol trilinoleate), LLO (glycerol dilinoleate-oleinate), LOO (glycerol linoleate-dioleinate), OOO (glycerol

  9. Monoacylglycerol Analysis Using MS/MS(ALL) Quadruple Time of Flight Mass Spectrometry.

    PubMed

    Gao, Fei; McDaniel, Justice; Chen, Emily Y; Rockwell, Hannah; Lynes, Matthew D; Tseng, Yu-Hua; Sarangarajan, Rangaprasad; Narain, Niven R; Kiebish, Michael A

    2016-01-01

    Monoacylglycerols (MAGs) are structural and bioactive metabolites critical for biological function. Development of facile tools for measuring MAG are essential to understand its role in different diseases and various pathways. A data-independent acquisition method, MS/MS(ALL), using electrospray ionization (ESI) coupled quadrupole time of flight mass spectrometry (MS), was utilized for the structural identification and quantitative analysis of individual MAG molecular species. Compared with other acylglycerols, diacylglycerols (DAG) and triacylglycerols (TAG), MAG characteristically presented as a dominant protonated ion, [M + H]⁺, and under low collision energy as fatty acid-like fragments due to the neutral loss of the glycerol head group. At low concentrations (<10 pmol/µL), where lipid-lipid interactions are rare, there was a strong linear correlation between ion abundance and MAG concentration. Moreover, using the MS/MS(ALL) method the major MAG species from human plasma and mouse brown and white adipose tissues were quantified in less than 6 min. Collectively, these results demonstrate that MS/MS(ALL) analysis of MAG is an enabling strategy for the direct identification and quantitative analysis of low level MAG species from biological samples with high throughput and sensitivity. PMID:27548241

  10. SWATH Mass Spectrometry Performance Using Extended Peptide MS/MS Assay Libraries.

    PubMed

    Wu, Jemma X; Song, Xiaomin; Pascovici, Dana; Zaw, Thiri; Care, Natasha; Krisp, Christoph; Molloy, Mark P

    2016-07-01

    The use of data-independent acquisition methods such as SWATH for mass spectrometry based proteomics is usually performed with peptide MS/MS assay libraries which enable identification and quantitation of peptide peak areas. Reference assay libraries can be generated locally through information dependent acquisition, or obtained from community data repositories for commonly studied organisms. However, there have been no studies performed to systematically evaluate how locally generated or repository-based assay libraries affect SWATH performance for proteomic studies. To undertake this analysis, we developed a software workflow, SwathXtend, which generates extended peptide assay libraries by integration with a local seed library and delivers statistical analysis of SWATH-quantitative comparisons. We designed test samples using peptides from a yeast extract spiked into peptides from human K562 cell lysates at three different ratios to simulate protein abundance change comparisons. SWATH-MS performance was assessed using local and external assay libraries of varying complexities and proteome compositions. These experiments demonstrated that local seed libraries integrated with external assay libraries achieve better performance than local assay libraries alone, in terms of the number of identified peptides and proteins and the specificity to detect differentially abundant proteins. Our findings show that the performance of extended assay libraries is influenced by the MS/MS feature similarity of the seed and external libraries, while statistical analysis using multiple testing corrections increases the statistical rigor needed when searching against large extended assay libraries.

  11. Dual Parallel Mass Spectrometry (LC1/MS2 and LC2/MS2) for Lipid and Vitamin D Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and electrospray ionization (ESI) MS are complementary techniques that provide different types of information for lipids such as triacylglycerols (TAGs), phospholipids, and fat-soluble vitamins. Since no one technique is by itsel...

  12. Analysis of potassium iodate reduction in tissue homogenates using high performance liquid chromatography-inductively coupled plasma-mass spectrometry.

    PubMed

    Cao, Xiaoxiao; Ma, Wei; Liu, Liejun; Xu, Jing; Wang, Haiyan; Li, Xiuwei; Wang, Jiangqing; Zhang, Jianhua; Wang, Zexi; Gu, Yunyou

    2015-10-01

    Potassium iodate (KIO3) and potassium iodide (KI) are the major salt iodization agents used worldwide. Unlike iodide (I(-)), iodate (IO3(-)) should be reduced to I(-) before it can be effectively used by the thyroid. In this study, we developed a new method for analyzing IO3(-) and I(-) in tissue homogenates using high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). We further applied the method to demonstrate the KIO3 reduction process by tissues in vitro. The effects of KIO3 on the total antioxidative activity (TAA) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) were also investigated here. Finally, we found that IO3(-) can be reduced to I(-) by tissue homogenates and IO3(-) irreversibly decreases the antioxidant capability of tissues. Our studies suggest that KIO3 might have a big effect on the redox balance of tissue and would further result in oxidative stress of organisms.

  13. Selective quantitation of the neurotoxin BMAA by use of hydrophilic-interaction liquid chromatography-differential mobility spectrometry-tandem mass spectrometry (HILIC-DMS-MS/MS).

    PubMed

    Beach, Daniel G; Kerrin, Elliott S; Quilliam, Michael A

    2015-11-01

    The neurotoxin β-N-methylamino-L-alanine (BMAA) has been reported in cyanobacteria and shellfish, raising concerns about widespread human exposure. However, inconsistent results for BMAA analysis have led to controversy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the most appropriate method for analysis of BMAA, but the risk of interference from isomers, other sample components, and the electrospray background is still present. We have investigated differential mobility spectrometry (DMS) as an ion filter to improve selectivity in the hydrophilic interaction liquid chromatographic (HILIC)-MS/MS determination of BMAA. We obtained standards for two BMAA isomers not previously analyzed by HILIC-MS, β-amino-N-methylalanine and 3,4-diaminobutanoic acid, and the typically used 2,4-diaminobutanoic acid and N-(2-aminoethyl)glycine. DMS separation of BMAA from these isomers was achieved and optimized conditions were used to develop a sensitive and highly selective multidimensional HILIC-DMS-MS/MS method. This work revealed current technical limitations of DMS for trace quantitation, and practical solutions were implemented. Accurate control of low levels of DMS carrier gas modifier was essential, but required external metering. The linearity of our optimized method was excellent from 0.01 to 6 μmol L(-1). The instrumental LOD was 0.4 pg BMAA injected on-column and the estimated method LOD was 20 ng g(-1) dry weight for BMAA in sample matrix. The method was used to analyze cycad plant tissue, a cyanobacterial reference material, and mussel tissues, by use of isotope-dilution quantitation with deuterated BMAA. This confirmed the presence of BMAA and several of its isomers in cycad and mussel tissues, including commercially available mussel tissue reference materials certified for other biotoxins. Graphical Abstract Differential Mobility Spectrometry is used to increases the selectivity of BMAA analysis by HILIC-MS/MS. PMID:26396078

  14. Quantitative, Multidrug Pain Medication Testing by Liquid Chromatography: Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Bodor, Geza S

    2016-01-01

    Chronic pain is often treated with narcotic analgesics. The most commonly used narcotic analgesics are the opiates (natural or modified compounds of the poppy plant) or opioids (synthetic chemicals that act on opiate receptors). While opiates and opioids are excellent analgesics, they can also have significant side effects that include respiratory depression, coma, or death. Tolerance, physical dependence, and addiction (psychological dependence) are other severe side effects of opioid use. Patients who develop dependence or addiction often times abuse other, non-opioid narcotics and may trade their prescription medication for illegal street drugs (called "diversion"). In order to minimize side effects, detect possible multidrug abuse and prove diversion, simultaneous monitoring of numerous prescription and illicit drugs is required. The method described in this chapter is for the quantitative measurement of 43 different drugs in urine. The panel includes narcotic pain medications, benzodiazepines, NIDA drugs, and other, commonly abused medications. The analytes of interests are injected in the presence of deuterated internal standards to correct for possible extraction inefficiencies, ion suppression, or other interferences. The sample is prepared by adding dilution buffer with the deuterated internal standards to the sample, followed by reversed-phase, gradient HPLC separation on a Phenyl-Hexyl column using water and methanol as mobile phases. Detection of the analytes of interest is done by isotope-dilution mass spectrometry on a triple-quadrupole tandem mass spectrometer following electrospray ionization in the positive mode. Mass spectrometric (MS) data are collected in the scheduled MRM (sMRM) mode. Two MRM transitions are monitored for each analyte and one MRM transition is monitored for each IS. Quantitation of the unknown analytes is achieved by comparing the peak area ratios of the analytes to that of the internal standards and reading the unknown

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

    EPA Science Inventory

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

  16. Characterization of a mixture of lobster digestive cysteine proteinases by ionspray mass spectrometry and tryptic mapping with LC--MS and LC--MS--MS

    NASA Astrophysics Data System (ADS)

    Thibault, P.; Pleasance, S.; Laycock, M. V.; Mackay, R. M.; Boyd, R. K.

    1991-12-01

    An inseparable mixture of two cysteine proteinases, isolated from the digestive tract of the American lobster, was investigated by ionspray mass spectrometry (ISP-MS), using a combination of infusion of intact proteins with on-line liquid chromatography--mass spectrometry (LC--MS) and LC--MS--MS analyses of tryptic digests. These data were interpreted by comparisons with predictions from results of molecular cloning of cysteine-proteinase-encoding messenger RNA sequences previously isolated from the lobster hepatopancreas. Investigations of the numbers of free thiol groups and of disulfide bonds were made by measuring the molecular weights of the alkylated proteins with and without prior reduction of disulfide bonds, and comparison with the corresponding data for the native proteins. Identification of tyrptic fragment peptides containing cysteine residues was facilitated by comparing LC--MS analyses of tryptic digests of denatured and of denatured and alkylated proteins, since such tryptic peptides are subject to shifts in both mass and retention time upon reduction and alkylation. Confirmation of amino acid sequences was obtained from fragment ion spectra of each tryptic peptide (alkylated or not) as it eluted from the column. Acquisition of such on-line LC--MS data was possible through use of the entire effluent from a standard 1 mm high performance liquid chromatography (HPLC) column by an IonsSpray® LC--MS interface (pneumatically assisted electrospray).

  17. Simultaneous determination of creatinine and creatine in human serum by double-spike isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Añón Álvarez, M Elena; Rodríguez, Felix; Menéndez, Francisco V Álvarez; García Alonso, J Ignacio

    2015-04-01

    This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors

  18. High-Speed MALDI MS/MS Imaging Mass Spectrometry Using Continuous Raster Sampling

    PubMed Central

    Prentice, Boone M.; Chumbley, Chad W.; Caprioli, Richard M.

    2015-01-01

    A matrix-assisted laser desorption/ionization time of flight/time of flight tandem mass spectrometer (MALDI TOF/TOF) has been used for high-speed precursor/fragment ion transition image acquisition. High throughput analysis is facilitated by a Nd:YLF solid state laser capable of pulse repetition rates up to 5 kHz, a high digitizer acquisition rate (up to 50 pixels/second), and continuous laser raster sampling. MS/MS experiments are enabled through the use of a precision timed ion selector, second source acceleration, and a dedicated collision cell. Continuous raster sampling is shown here to facilitate rapid MS/MS ion image acquisition from thin tissue sections for the drug rifampicin and of a common kidney lipid, SM4s(d18:1/24:1). The ability to confirm the structural identity of an analyte as part of the MS/MS imaging experiment is an essential part of the analysis. Additionally, the increase in sensitivity and specificity afforded by an MS/MS approach is highly advantageous, especially when interrogating complex chemical environments such as those in biological tissues. Herein, we report continuous laser raster sampling TOF/TOF imaging methodologies which demonstrate 8-14 fold increases in throughput compared to existing MS/MS instrumentation, an important advantage when imaging large areas on tissues. PMID:26149115

  19. New insights from MALDI-ToF MS, NMR, and GC-MS: mass spectrometry techniques applied to palynology.

    PubMed

    Moore, S E M; Hemsley, A R; French, A N; Dudley, E; Newton, R P

    2006-08-01

    The present study for the first time describes the application of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-ToF MS) to palynology. With an accessible mass range of up to about 350,000 Da at subpicomolar range, this technique is ideal for the characterisation of bio-macromolecules, such as sporopollenin, found in fossil and extant pollen and spore walls, which often can only be isolated in very small quantities. At this stage, the limited solubility of sporopollenin allows for the identification of sections of this biopolymer, but with the optimisation of MALDI-ToF matrices, further structure elucidation will become possible. Furthermore, gas chromatography-mass spectrometry (GC-MS) and (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy data obtained from a number of experiments revealed that some previously reported data were misinterpreted. These results add support to the hypothesis that common plasticizers were wrongly described as sporopollenin compounds.

  20. Beyond the proteome: Mass Spectrometry Special Interest Group (MS-SIG) at ISMB/ECCB 2013

    SciTech Connect

    Ryu, Soyoung; Payne, Samuel H.; Schaab, Christoph; Xiao, Wenzhong

    2014-07-02

    Mass spectrometry special interest group (MS-SIG) aims to bring together experts from the global research community to discuss highlights and challenges in the field of mass spectrometry (MS)-based proteomics and computational biology. The rapid echnological developments in MS-based proteomics have enabled the generation of a large amount of meaningful information on hundreds to thousands of proteins simultaneously from a biological sample; however, the complexity of the MS data require sophisticated computational algorithms and software for data analysis and interpretation. This year’s MS-SIG meeting theme was ‘Beyond the Proteome’ with major focuses on improving protein identification/quantification and using proteomics data to solve interesting problems in systems biology and clinical research.

  1. Ion mobility spectrometry-mass spectrometry (IMS-MS) for on- and offline analysis of atmospheric gas and aerosol species

    NASA Astrophysics Data System (ADS)

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; Budisulistiorini, Sri H.; Zhang, Haofei; Surratt, Jason D.; Knochenmuss, Richard; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose-Luis; Canagaratna, Manjula R.

    2016-07-01

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS-MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS-MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI-IMS-MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambient field campaign in the forested SE US. The ambient IMS-MS signals are consistent with laboratory IMS-MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS-MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS-MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of oligomers, and confirm the

  2. Atmospheric-pressure chemical ionization tandem mass spectrometry (APGC/MS/MS) an alternative to high-resolution mass spectrometry (HRGC/HRMS) for the determination of dioxins.

    PubMed

    van Bavel, Bert; Geng, Dawei; Cherta, Laura; Nácher-Mestre, Jaime; Portolés, Tania; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; Dunstan, Jody; Jones, Rhys; Kotz, Alexander; Winterhalter, Helmut; Malisch, Rainer; Traag, Wim; Hagberg, Jessika; Ericson Jogsten, Ingrid; Beltran, Joaquim; Hernández, Félix

    2015-09-01

    The use of a new atmospheric-pressure chemical ionization source for gas chromatography (APGC) coupled with a tandem quadrupole mass spectrometry (MS/MS) system, as an alternative to high-resolution mass spectrometry (HRMS), for the determination of PCDDs/PCDFs is described. The potential of using atmospheric-pressure chemical ionization (APCI) coupled to a tandem quadrupole analyzer has been validated for the identification and quantification of dioxins and furans in different complex matrices. The main advantage of using the APCI source is the soft ionization at atmospheric pressure, which results in very limited fragmentation. APCI mass spectra are dominated by the molecular ion cluster, in contrast with the high energy ionization process under electron ionization (EI). The use of the molecular ion as the precursor ion in MS/MS enhances selectivity and, consequently, sensitivity by increasing the signal-to-noise ratios (S/N). For standard solutions of 2,3,7,8-TCDD, injections of 10 fg in the splitless mode on 30- or 60-m-length, 0.25 mm inner diameter (id), and 25 μm film thickness low-polarity capillary columns (DB5MS type), signal-to-noise (S/N) ratios of >10:1 were routinely obtained. Linearity was achieved in the region (correlation coefficient of r(2) > 0.998) for calibration curves ranging from 100 fg/μL to 1000 pg/μL. The results from a wide variety of complex samples, including certified and standard reference materials and samples from several QA/QC studies, which were previously analyzed by EI HRGC/HRMS, were compared with the results from the APGC/MS/MS system. Results between instruments showed good agreement both in individual congeners and toxic equivalence factors (TEQs). The data show that the use of APGC in combination with MS/MS for the analysis of dioxins has the same potential, in terms of sensitivity and selectivity, as the traditional HRMS instrumentation used for this analysis. However, the APCI/MS/MS system, as a benchtop system, is

  3. OpenMS: a flexible open-source software platform for mass spectrometry data analysis.

    PubMed

    Röst, Hannes L; Sachsenberg, Timo; Aiche, Stephan; Bielow, Chris; Weisser, Hendrik; Aicheler, Fabian; Andreotti, Sandro; Ehrlich, Hans-Christian; Gutenbrunner, Petra; Kenar, Erhan; Liang, Xiao; Nahnsen, Sven; Nilse, Lars; Pfeuffer, Julianus; Rosenberger, George; Rurik, Marc; Schmitt, Uwe; Veit, Johannes; Walzer, Mathias; Wojnar, David; Wolski, Witold E; Schilling, Oliver; Choudhary, Jyoti S; Malmström, Lars; Aebersold, Ruedi; Reinert, Knut; Kohlbacher, Oliver

    2016-08-30

    High-resolution mass spectrometry (MS) has become an important tool in the life sciences, contributing to the diagnosis and understanding of human diseases, elucidating biomolecular structural information and characterizing cellular signaling networks. However, the rapid growth in the volume and complexity of MS data makes transparent, accurate and reproducible analysis difficult. We present OpenMS 2.0 (http://www.openms.de), a robust, open-source, cross-platform software specifically designed for the flexible and reproducible analysis of high-throughput MS data. The extensible OpenMS software implements common mass spectrometric data processing tasks through a well-defined application programming interface in C++ and Python and through standardized open data formats. OpenMS additionally provides a set of 185 tools and ready-made workflows for common mass spectrometric data processing tasks, which enable users to perform complex quantitative mass spectrometric analyses with ease. PMID:27575624

  4. OpenMS: a flexible open-source software platform for mass spectrometry data analysis.

    PubMed

    Röst, Hannes L; Sachsenberg, Timo; Aiche, Stephan; Bielow, Chris; Weisser, Hendrik; Aicheler, Fabian; Andreotti, Sandro; Ehrlich, Hans-Christian; Gutenbrunner, Petra; Kenar, Erhan; Liang, Xiao; Nahnsen, Sven; Nilse, Lars; Pfeuffer, Julianus; Rosenberger, George; Rurik, Marc; Schmitt, Uwe; Veit, Johannes; Walzer, Mathias; Wojnar, David; Wolski, Witold E; Schilling, Oliver; Choudhary, Jyoti S; Malmström, Lars; Aebersold, Ruedi; Reinert, Knut; Kohlbacher, Oliver

    2016-08-30

    High-resolution mass spectrometry (MS) has become an important tool in the life sciences, contributing to the diagnosis and understanding of human diseases, elucidating biomolecular structural information and characterizing cellular signaling networks. However, the rapid growth in the volume and complexity of MS data makes transparent, accurate and reproducible analysis difficult. We present OpenMS 2.0 (http://www.openms.de), a robust, open-source, cross-platform software specifically designed for the flexible and reproducible analysis of high-throughput MS data. The extensible OpenMS software implements common mass spectrometric data processing tasks through a well-defined application programming interface in C++ and Python and through standardized open data formats. OpenMS additionally provides a set of 185 tools and ready-made workflows for common mass spectrometric data processing tasks, which enable users to perform complex quantitative mass spectrometric analyses with ease.

  5. Tandem mass spectrometry in metallomics and the involving role of ICP-MS detection: a review.

    PubMed

    Vogiatzis, C G; Zachariadis, G A

    2014-03-28

    Metallomics is a relatively new branch of omics with a growing interest. The study of metallomes is becoming more focused in certain metabolites and the screening of various categories of analytes using a robust analytical methodology is more than appealing. In this context, when dealing with the challenge of identifying a certain species or specify a particular molecular structure, tandem mass spectrometry (MS/MS) is a reliable tool. Moreover, MS/MS instrumentation is recommended in hyphenated chromatographic techniques with MS detection such as LC-MS, where primary molecular species suffer minor fragmentation (soft-ionization techniques). ICP-MS is widely used in metallomics with its main advantages being the provided high sensitivity and selectivity. Usually, analyzes utilize ICP-MS as the main detection. Its role in proteomics is significant as an alternating choice for protein and peptide quantifications. In this review, we discuss modern trends and applications of MS/MS in the important and growing field of metallomics. These reports concern the identification, characterization and determination of various metal species such as metalloproteins, metallo-DNA adducts, metal-labeled molecules and other metal binding biomolecules. Such assays also present new and interesting hyphenated instrumentation and novel sophisticated apparatus. In addition, we designate the role of ICP-MS in the mentioned contributions and in the same scope we highlight some general analytical strategies.

  6. Quantification of Iohexol in Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Vicente, Faye B; Vespa, Gina; Miller, Alan; Haymond, Shannon

    2016-01-01

    Iohexol is a nonradioactive contrast medium, and its clearance from serum or urine is used to measure glomerular filtration rate (GFR). GFR is the most useful indicator of kidney function and progression of kidney disease. GFR determination using iohexol clearance is increasingly being applied in clinical practice, given its advantages over and correlation with inulin. We describe a high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method for iohexol clearance, requiring only 50 μL of serum. The sample preparation involves protein precipitation with LC/MS-grade methanol, containing ioversol as the internal standard. Samples are centrifuged and supernatant is dried under nitrogen gas at room temperature. Samples are reconstituted with mobile phase (ammonium acetate-formic acid-water). Iohexol is separated using an HPLC gradient method on a C-8 analytical column. MS/MS detection is in the multiple-reaction monitoring (MRM) mode and the transitions monitored are m/z 822.0 to m/z 804.0 and m/z 807.0 to m/z 588.0 for iohexol and ioversol, respectively.

  7. Comparison of enzyme kinetics of warfarin analyzed by LC-MS/MS QTrap and differential mobility spectrometry.

    PubMed

    Shaik, Abdul Naveed; Grater, Richard; Lulla, Mukesh; Williams, David A; Gan, Lawrence L; Bohnert, Tonika; LeDuc, Barbara W

    2016-01-01

    Warfarin is an anticoagulant used in the treatment of thrombosis and thromboembolism. It is given as a racemic mixture of R and S enantiomers. These two enantiomers show differences in metabolism by CYPs: S-warfarin undergoes 7 hydroxylation by CYP2C9 and R-warfarin by CYP3A4 to form 10 hydroxy warfarin. In addition, warfarin is acted upon by different CYPs to form the minor metabolites 3'-hydroxy, 4'-hydroxy, 6-hydroxy, and 8-hydroxy warfarin. For analysis, separation of these metabolites is necessary since all have the same m/z ratio and similar fragmentation pattern. Enzyme kinetics for the formation of all of the six hydroxylated metabolites of warfarin from human liver microsomes were determined using an LC-MS/MS QTrap and LC-MS/MS with a differential mobility spectrometry (DMS) (SelexION™) interface to compare the kinetic parameters. These two methods were chosen to compare their selectivity and sensitivity. Substrate curves for 3'-OH, 4'-OH, 6-OH, 7-OH, 8-OH and 10-OH warfarin formation were generated to determine the kinetic parameters (Km and Vmax) in human liver microsomal preparations. The limit of quantitation (LOQ) for all the six hydroxylated metabolites of warfarin were in the range of 1-3nM using an LC-MS/MS QTrap method which had a run time of 22min. In contrast, the LOQ for all the six hydroxylated metabolites using DMS interface technology was 100nM with a run time of 2.8min. We compare these two MS methods and discuss the kinetics of metabolite formation for the metabolites generated from racemic warfarin. In addition, we show inhibition of major metabolic pathways of warfarin by sulfaphenazole and ketoconazole which are known specific inhibitors of CYP2C9 and CYP3A4 respectively. PMID:26655108

  8. Improving Alpha Spectrometry Energy Resolution by Ion Implantation with ICP-MS

    SciTech Connect

    Dion, Michael P.; Liezers, Martin; Farmer, Orville T.; Miller, Brian W.; Morley, Shannon M.; Barinaga, Charles J.; Eiden, Gregory C.

    2015-01-01

    We report results of a novel technique using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) as a method of source preparation for alpha spectrometry. This method produced thin, contaminant free 241Am samples which yielded extraordinary energy resolution which appear to be at the lower limit of the detection technology used in this research.

  9. Accurate Mass MS/MS/MS Analysis of Siderophores Ferrioxamine B and E1 by Collision-Induced Dissociation Electrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Sidebottom, Ashley M.; Karty, Jonathan A.; Carlson, Erin E.

    2015-11-01

    Siderophores are bacterially secreted, small molecule iron chelators that facilitate the binding of insoluble iron (III) for reuptake and use in various biological processes. These compounds are classified by their iron (III) binding geometry, as dictated by subunit composition and include groups such as the trihydroxamates (hexadentate ligand) and catecholates (bidentate). Small modifications to the core structure such as acetylation, lipid tail addition, or cyclization, make facile characterization of new siderophores difficult by molecular ion detection alone (MS1). We have expanded upon previous fragmentation-directed studies using electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS/MS/MS) and identified diagnostic MS3 features from the trihydroxamate siderophore class for ferrioxamine B and E1 by accurate mass. Diagnostic features for MS3 include C-C, C-N, amide, and oxime cleavage events with proposed losses of water and -CO from the iron (III) coordination sites. These insights will facilitate the discovery of novel trihydroxamate siderophores from complex sample matrices.

  10. Quantitation of the Oral Anticoagulants Dabigatran, Rivaroxaban, Apixaban, and Warfarin in Plasma Using Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry (UPLC-MS/MS).

    PubMed

    Noguez, Jaime H; Ritchie, James C

    2016-01-01

    This chapter describes a method to measure the oral anticoagulants dabigatran, rivaroxaban, apixaban, and warfarin in plasma samples using ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS/MS). The instrument is operated in multiple reaction monitoring (MRM) mode with an electrospray ionization (ESI) source in positive ionization mode. Samples are extracted with a 90:10 methanol/0.1 N hydrochloric acid solution containing stable isotope-labeled internal standards for each analyte. After centrifugation the supernatant is transferred to a mass spectrometry vial, injected onto the UPLC-ESI-MS/MS, and quantified using an eight-point calibration curve.

  11. Stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet/inductively coupled plasma mass spectrometry for analysis of thyroxine in urine samples.

    PubMed

    Fan, Wenying; Mao, Xiangju; He, Man; Chen, Beibei; Hu, Bin

    2013-11-29

    tIn this work, polyethyleneglycol (PEG)/hydroxyl polydimethylsiloxane (OH-PDMS)/γ -mercaptopropyltrimethoxysilane (γ -MPTS) coated stir bar was prepared by sol–gel process and its extraction performance for the extraction of amphoteric thyroxines (3,3',5,5'-tetraiodothyronin, T(4); 3,3',5-triiodothyronine, T(3); reversed-3,3',5-triiodothyronine, rT(3)) and their metabolite (3,5-diiodothyronine,T2) was studied. The preparation reproducibility of PEG/OH-PDMS/γ -MPTS coated stir bar was investigated, and the relative standard deviations (RSDs) in the same batch and among different batches were 3.3–14.3% (n = 5) and 7.7–16.6% (n = 3), respectively. The prepared PEG/OH-PDMS/γ -MPTS coated stir bar could be reused for more than 20 times. Based on this fact, a novel method of stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV)and HPLC-inductively coupled plasma mass spectrometry (ICP-MS) for the analysis of target thyroxinesin human urine samples was developed. The influencing factors of SBSE, such as sample pH, extraction time, stirring rate, salt effect, desorption solution and desorption time, were studied in detail, and the analytical performance of the proposed method was evaluated under the optimized conditions. The enrichment factors (EFs) of the developed method for four target thyroxines were in the range of 14.9–70.4(theoretical enrichment factor was 100). The RSDs were ranging from 4.0% to 13.8% for SBSE-HPLC-UV (c = 25 μg/L, n = 6) and from 3.7% to 6.1% for SBSE-HPLC-ICP-MS (c = 0.5 μg/L, n = 5). The linear range obtained by SBSE-HPLC-UV was 2–500 μg/L for T(2)and 5–500 μg/L for rT3, T(3)and T(4), with correlation coefficients (r) ranging from 0.9957 to 0.9998, respectively, while the linear range obtained by SBSE-HPLC-ICP-MS was 0.05–500 μg/L for T(2) and rT(3), 0.10–200 μg/L for T(3) and 0.05–200 μg/L for T(4)with r ranging from 0.9979 to 0.9998, respectively. The

  12. Complementary arsenic speciation methods: A review

    NASA Astrophysics Data System (ADS)

    Nearing, Michelle M.; Koch, Iris; Reimer, Kenneth J.

    2014-09-01

    The toxicity of arsenic greatly depends on its chemical form and oxidation state (speciation) and therefore accurate determination of arsenic speciation is a crucial step in understanding its chemistry and potential risk. High performance liquid chromatography with inductively coupled mass spectrometry (HPLC-ICP-MS) is the most common analysis used for arsenic speciation but it has two major limitations: it relies on an extraction step (usually from a solid sample) that can be incomplete or alter the arsenic compounds; and it provides no structural information, relying on matching sample peaks to standard peaks. The use of additional analytical methods in a complementary manner introduces the ability to address these disadvantages. The use of X-ray absorption spectroscopy (XAS) with HPLC-ICP-MS can be used to identify compounds not extracted for HPLC-ICP-MS and provide minimal processing steps for solid state analysis that may help preserve labile compounds such as those containing arsenicsbnd sulfur bonds, which can degrade under chromatographic conditions. On the other hand, HPLC-ICP-MS is essential in confirming organoarsenic compounds with similar white line energies seen by using XAS, and identifying trace arsenic compounds that are too low to be detected by XAS. The complementary use of electrospray mass spectrometry (ESI-MS) with HPLC-ICP-MS provides confirmation of arsenic compounds identified during the HPLC-ICP-MS analysis, identification of unknown compounds observed during the HPLC-ICP-MS analysis and further resolves HPLC-ICP-MS by identifying co-eluting compounds. In the complementary use of HPLC-ICP-MS and ESI-MS, HPLC-ICP-MS helps to focus the ESI-MS selection of ions. Numerous studies have shown that the information obtained from HPLC-ICP-MS analysis can be greatly enhanced by complementary approaches.

  13. Detection of Radiation-Exposure Biomarkers by Differential Mobility Prefiltered Mass Spectrometry (DMS-MS)

    PubMed Central

    Coy, Stephen L.; Krylov, Evgeny V.; Schneider, Bradley B.; Covey, Thomas R.; Brenner, David J.; Tyburski, John B.; Patterson, Andrew D.; Krausz, Kris W.; Fornace, Albert J.; Nazarov, Erkinjon G.

    2010-01-01

    Technology to enable rapid screening for radiation exposure has been identified as an important need, and, as a part of a NIH / NIAD effort in this direction, metabolomic biomarkers for radiation exposure have been identified in a recent series of papers. To reduce the time necessary to detect and measure these biomarkers, differential mobility spectrometry – mass spectrometry (DMS-MS) systems have been developed and tested. Differential mobility ion filters preselect specific ions and also suppress chemical noise created in typical atmospheric-pressure ionization sources (ESI, MALDI, and others). Differential-mobility-based ion selection is based on the field dependence of ion mobility, which, in turn, depends on ion characteristics that include conformation, charge distribution, molecular polarizability, and other properties, and on the transport gas composition which can be modified to enhance resolution. DMS-MS is able to resolve small-molecule biomarkers from nearly-isobaric interferences, and suppresses chemical noise generated in the ion source and in the mass spectrometer, improving selectivity and quantitative accuracy. Our planar DMS design is rapid, operating in a few milliseconds, and analyzes ions before fragmentation. Depending on MS inlet conditions, DMS-selected ions can be dissociated in the MS inlet expansion, before mass analysis, providing a capability similar to MS/MS with simpler instrumentation. This report presents selected DMS-MS experimental results, including resolution of complex test mixtures of isobaric compounds, separation of charge states, separation of isobaric biomarkers (citrate and isocitrate), and separation of nearly-isobaric biomarker anions in direct analysis of a bio-fluid sample from the radiation-treated group of a mouse-model study. These uses of DMS combined with moderate resolution MS instrumentation indicate the feasibility of field-deployable instrumentation for biomarker evaluation. PMID:20305793

  14. Forensic applications of desorption electrospray ionisation mass spectrometry (DESI-MS).

    PubMed

    Morelato, Marie; Beavis, Alison; Kirkbride, Paul; Roux, Claude

    2013-03-10

    Desorption electrospray ionisation mass spectrometry (DESI-MS) is an emerging analytical technique that enables in situ mass spectrometric analysis of specimens under ambient conditions. It has been successfully applied to a large range of forensically relevant materials. This review assesses and highlights forensic applications of DESI-MS including the analysis and detection of illicit drugs, explosives, chemical warfare agents, inks and documents, fingermarks, gunshot residues and drugs of abuse in urine and plasma specimens. The minimal specimen preparation required for analysis and the sensitivity of detection achieved offer great advantages, especially in the field of forensic science.

  15. Rapid classification of perfumes by extractive electrospray ionization mass spectrometry (EESI-MS).

    PubMed

    Chingin, Konstantin; Gamez, Gerardo; Chen, Huanwen; Zhu, Liang; Zenobi, Renato

    2008-07-01

    Extractive electrospray ionization mass spectrometry (EESI-MS) was applied to rapid fingerprinting of various perfumes for quality classification. Unique EESI-MS fingerprints of ten famous brands were obtained. This technique was shown to be applicable to rapid forgery detection on the example of an authentic and a counterfeit 'Miss Dior' fragrance by Christian Dior. We believe that the high throughput and simplicity of this sample-preparation-free method can be advantageous in the perfume industry, for instance when applied to online quality control.

  16. Arsenosugar identification in seaweed extracts using high-performance liquid chromatography/electrospray ion trap mass spectrometry.

    PubMed

    Miguens-Rodriguez, Maria; Pickford, Russell; Thomas-Oates, Jane E; Pergantis, Spiros A

    2002-01-01

    The development of analytical techniques suitable for providing structural information on a wide range of elemental species is a growing necessity. For arsenic speciation a variety of mass spectrometric techniques, mainly inductively coupled plasma mass spectrometry (ICP-MS) and electrospray tandem mass spectrometry (ES-MS/MS) coupled on-line with high-performance liquid chromatography (HPLC), are in use. In this paper we report the identification of arsenic species present in samples of marine origin (seaweed extracts) using ES ion trap mass spectrometry (IT) multistage mass spectrometry (MS(n)). Both reversed-phase and anion-exchange HPLC have been coupled on-line to ES-ITMS. Product ion scans with multiple stages of tandem MS (MS(n); n=2-4) were used to acquire diagnostic data for each arsenosugar. The spectra contain structurally characteristic fragment ions for each of the arsenosugars examined. In addition it was observed that upon successive stages of collision-induced dissociation (CID) a common product ion (m/z 237) was formed from all four arsenosugars examined. This product ion has the potential to be used as an indicator for the presence of dimethylated arsenosugars (dimethylarsinoylribosides). The HPLC/ES-ITMS(n) method developed allows the sensitive identification of arsenosugars present in crude seaweed extracts without the need for extended sample preparation. In fact, sample preparation requirements are identical to those typically employed for HPLC/ICP-MS analysis. Additionally, the resulting product ions are structurally diagnostic of the arsenosugars examined, and tandem mass spectra are reproducible and correspond well to those obtained using other low-energy CID techniques. As a result, the HPLC/ES-ITMS(n) approach minimises the potential for arsenic species misidentification and has great potential as a means of overcoming the need for characterised standards.

  17. Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS).

    PubMed

    Looi, Wen Donq; Brown, Blake; Chamand, Laura; Brajter-Toth, Anna

    2016-03-01

    A new online electrochemistry/liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS) system with a simple electrochemical thin-layer flow-through cell was developed and tested using N,N-dimethyl-p-phenylenediamine (DMPA) as a model probe. Although oxidation of DMPA is observed as a result of ionization of LS in positive ion mode LS DESI, application of voltage to the online electrochemical (EC) cell in EC/LS DESI MS increases yields of oxidation products. An advantage of LS DESI MS is its sensitivity in aqueous electrolyte solutions, which improves efficiency of electrochemical reactions in EC/LS DESI MS. In highly conductive low pH aqueous buffer solutions, oxidation efficiency is close to 100%. EC/ESI MS typically requires mixed aqueous/organic solvents and low electrolyte concentrations for efficient ionization in MS, limiting efficiency of electrochemistry online with MS. Independently, the results verify higher electrochemical oxidation efficiency during positive mode ESI than during LS DESI.

  18. 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.

  19. Quantification of Docetaxel in Serum Using Turbulent Flow Liquid Chromatography Electrospray Tandem Mass Spectrometry (TFC-HPLC-ESI-MS/MS).

    PubMed

    Crutchfield, Christopher A; Marzinke, Mark A; Clarke, William A

    2016-01-01

    Docetaxel is a second-generation taxane and is used clinically as an anti-neoplastic agent in cancer chemotherapy via an anti-mitotic mechanism. Its efficacy is limited to a narrow therapeutic window. Inappropriately high concentrations may cause erythema, fluid retention, nausea, diarrhea, and neutropenia. As a result, dosing recommendations have changed from high dosage loading every 3 weeks to lower dosage loading weekly. We describe a method that can be used for therapeutic drug monitoring of docetaxel levels using turbulent flow liquid chromatography electrospray tandem mass spectrometry (TFC-HPLC-ESI-MS/MS). The method is rapid, requiring only 6.3 min per analytical run following a simple protein crash. The method requires only 100 μL of serum. Concentrations of docetaxel were quantified by a calibration curve relating the peak-area ratio of docetaxel to a deuterated internal standard (docetaxel-D9). The method was linear from 7.8 to 1000 ng/mL, with imprecision ≤6.2 %.

  20. Chiral liquid chromatography-mass spectrometry (LC-MS/MS) method development for the detection of salbutamol in urine samples.

    PubMed

    Chan, Sue Hay; Lee, Warren; Asmawi, Mohd Zaini; Tan, Soo Choon

    2016-07-01

    A sequential solid-phase extraction (SPE) method was developed and validated using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the detection and quantification of salbutamol enantiomers in porcine urine. Porcine urine samples were hydrolysed with β-glucuronidase/arylsulfatase from Helix pomatia and then subjected to a double solid-phase extraction (SPE) first using the Abs-Elut Nexus SPE and then followed by the Bond Elut Phenylboronic Acid (PBA) SPE. The salbutamol enantiomers were separated using the Astec CHIROBIOTIC™ T HPLC column (3.0mm×100mm; 5μm) maintained at 15°C with a 15min isocratic run at a flow rate of 0.4mL/min. The mobile phase constituted of 5mM ammonium formate in methanol. Salbutamol and salbutamol-tert-butyl-d9 (internal standard, IS) was monitored and quantified with the multiple reaction monitoring (MRM) mode. The method showed good linearity for the range of 0.1-10ng/mL with limit of quantification at 0.3ng/mL. Analysis of the QC samples showed intra- and inter-assay precisions to be less than 5.04%, and recovery ranging from 83.82 to 102.33%. PMID:27232053

  1. [Evaluation of mass spectrometry: MALDI-TOF MS for fast and reliable yeast identification].

    PubMed

    Relloso, María S; Nievas, Jimena; Fares Taie, Santiago; Farquharson, Victoria; Mujica, María T; Romano, Vanesa; Zarate, Mariela S; Smayevsky, Jorgelina

    2015-01-01

    The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique known as MALDI-TOF MS is a tool used for the identification of clinical pathogens by generating a protein spectrum that is unique for a given species. In this study we assessed the identification of clinical yeast isolates by MALDI-TOF MS in a university hospital from Argentina and compared two procedures for protein extraction: a rapid method and a procedure based on the manufacturer's recommendations. A short protein extraction procedure was applied in 100 isolates and the rate of correct identification at genus and species level was 98.0%. In addition, we analyzed 201 isolates, previously identified by conventional methods, using the methodology recommended by the manufacturer and there was 95.38% coincidence in the identification at species level. MALDI TOF MS showed to be a fast, simple and reliable tool for yeast identification.

  2. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and its Application in Life Sciences

    NASA Astrophysics Data System (ADS)

    Xu, Gu-feng; Wang, Hong-mei

    2001-08-01

    Inductively-coupled plasma mass spectrometry (ICP-MS) has made much progress since its birth in the late 1990s. This paper will give a rather systematic overview on the use of this technique in new devices and technologies related to plasma source, sample-introducing device and detecting spectrometer etc. In this overview, an emphasis will be put on the evaluation of the ICP-MS technique in combination with a series of physical, chemical and biological techniques, such as laser ablation (LA), capillary electrophoresis (CE) and high performance liquid chromatograph (HPLC), along with their representative high accuracy and high sensitivity. Finally, comprehensive and fruitful applications of the ICP-MS and its combinative techniques in the detection of trace metallic elements and isotopes in complex biological and environmental samples will be revealed.

  3. Transversal modulation ion mobility spectrometry (IMS) coupled with mass spectrometry (MS): exploring the IMS-IMS-MS possibilities of the instrument.

    PubMed

    Vidal-de-Miguel, G; Macía, M; Barrios, C; Cuevas, J

    2015-02-01

    A prototype is introduced based on the transversal modulation ion mobility spectrometry (TMIMS) technique, which provides a continuous output of mobility-selected ions, greatly easing the synchronization between different analyzing stages. In the new architecture, two stages of filtration are used to drastically reduce the background produced by one stage alone. Two-stages TMIMS was coupled with two different atmospheric pressure interface mass spectrometers (MS). The new system enables IMS-IMS-MS analysis and other modes of operation: IMS prefiltration, IMS-IMS, and full transmission mode. It provides a resolving power R > 60 in IMS mode, and R > 40 in each stage of IMS-IMS mode. 2-Propanol vapors were introduced in one of the stages to enhance the mobility variations, and their effect was studied on a set of tetraalkylammonium ions. We found that concentrations as low as 1% (in partial pressure) produce mobility variations as high as 20%, which suggest that IMS-IMS separation using dried N2 (in one stage) and a dopant (in the other stage), could be a very powerful way to enhance the separation capacity of the IMS-IMS prefiltration approach.

  4. Identification of bacterial plant pathogens using multilocus PCR and electrospray ionization-mass spectrometry (PCR/ESI-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS, previously known as “TIGER”) utilizes PCR with broad range primers to amplify products from wide array of organisms within a taxonomic group, followed by analysis of PCR amplicons using mass spectrometry. Computer analysis of precise masses ...

  5. Rapid tomato volatile profiling by using proton-transfer reaction mass spectrometry (PTR-MS).

    PubMed

    Farneti, Brian; Cristescu, Simona M; Costa, Guglielmo; Harren, Frans J M; Woltering, Ernst J

    2012-05-01

    The availability of rapid and accurate methods to assess fruit flavor is of utmost importance to support quality control especially in the breeding phase. Breeders need more information and analytical tools to facilitate selection for complex multigenic traits such as flavor quality. In this study, it is shown that proton-transfer reaction mass spectrometry (PTR-MS) is a suitable method to monitor at high sensitivity the emission of volatiles determining the tomato aromatic profile such as hexanal, hexenals, methanol, ethanol, and acetaldehyde. The volatiles emitted by 14 tomato varieties (at red stage) were analyzed by 2 solvent-free headspace methods: solid-phase microextraction/gas chromatography MS and PTR-MS. Multivariate statistics (principal component analysis and cluster analysis) of the PTR-MS results allow an unambiguous separation between varieties, especially with a clear fingerprinting separation between the different tomato types: round truss, cocktail, and cherry tomatoes. PTR-MS was also successfully used to monitor the changes in volatile profiles during postharvest ripening and storage. PMID:22509736

  6. OpenMS – An open-source software framework for mass spectrometry

    PubMed Central

    Sturm, Marc; Bertsch, Andreas; Gröpl, Clemens; Hildebrandt, Andreas; Hussong, Rene; Lange, Eva; Pfeifer, Nico; Schulz-Trieglaff, Ole; Zerck, Alexandra; Reinert, Knut; Kohlbacher, Oliver

    2008-01-01

    Background Mass spectrometry is an essential analytical technique for high-throughput analysis in proteomics and metabolomics. The development of new separation techniques, precise mass analyzers and experimental protocols is a very active field of research. This leads to more complex experimental setups yielding ever increasing amounts of data. Consequently, analysis of the data is currently often the bottleneck for experimental studies. Although software tools for many data analysis tasks are available today, they are often hard to combine with each other or not flexible enough to allow for rapid prototyping of a new analysis workflow. Results We present OpenMS, a software framework for rapid application development in mass spectrometry. OpenMS has been designed to be portable, easy-to-use and robust while offering a rich functionality ranging from basic data structures to sophisticated algorithms for data analysis. This has already been demonstrated in several studies. Conclusion OpenMS is available under the Lesser GNU Public License (LGPL) from the project website at . PMID:18366760

  7. Mass Spectrometry Data from the Biological MS Data and Software Distribution Center

    DOE Data Explorer

    Anderson, Gordon

    The mass spectrometry capabilities at Pacific Northwest National Laboratory (PNNL) are primarily applied to biological research, with an emphasis on proteomics and metabolomics. Many of these cutting-edge mass spectrometry capabilities and bioinformatics methods are housed in the Department of Energy's Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility operated by PNNL. These capabilities have been developed and acquired through cooperation between the EMSL national scientific user program and PNNL programmatic research. At the website of the Biological MS Data and Software Distribution Center, the following resources are made available: PNNL-developed software tools and source code, PNNL-generated raw data and processed results, links to publications that used the data and results available on this site, and tutorials and user manuals. [taken from http://omics.pnl.gov/

  8. Tandem mass spectrometry approach for the investigation of the steroidal metabolism: structure-fragmentation relationship (SFR) in anabolic steroids and their metabolites by ESI-MS/MS analysis.

    PubMed

    Musharraf, Syed Ghulam; Ali, Arslan; Khan, Naik Tameem; Yousuf, Maria; Choudhary, Muhammad Iqbal; Atta-ur-Rahman

    2013-02-01

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to investigate the effect of different substitutions introduced during metabolism on fragmentation patterns of four anabolic steroids including methyltestosterone, methandrostenolone, cis-androsterone and adrenosterone, along with their metabolites. Collision-induced dissociation (CID) analysis was performed to correlate the major product ions of 19 steroids with structural features. The analysis is done to portray metabolic alteration, such as incorporation or reduction of double bonds, hydroxylations, and/or oxidation of hydroxyl moieties to keto functional group on steroidal skeleton which leads to drastically changed product ion spectra from the respective classes of steroids, therefore, making them difficult to identify. The comparative ESI-MS/MS study also revealed some characteristic peaks to differentiate different steroidal metabolites and can be useful for the unambiguous identification of anabolic steroids in biological fluid. Moreover, LC-ESI-MS/MS analysis of fermented extract of methyltestosterone, obtained by Macrophomina phaseolina was also investigated. PMID:23159734

  9. Tandem mass spectrometry approach for the investigation of the steroidal metabolism: structure-fragmentation relationship (SFR) in anabolic steroids and their metabolites by ESI-MS/MS analysis.

    PubMed

    Musharraf, Syed Ghulam; Ali, Arslan; Khan, Naik Tameem; Yousuf, Maria; Choudhary, Muhammad Iqbal; Atta-ur-Rahman

    2013-02-01

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to investigate the effect of different substitutions introduced during metabolism on fragmentation patterns of four anabolic steroids including methyltestosterone, methandrostenolone, cis-androsterone and adrenosterone, along with their metabolites. Collision-induced dissociation (CID) analysis was performed to correlate the major product ions of 19 steroids with structural features. The analysis is done to portray metabolic alteration, such as incorporation or reduction of double bonds, hydroxylations, and/or oxidation of hydroxyl moieties to keto functional group on steroidal skeleton which leads to drastically changed product ion spectra from the respective classes of steroids, therefore, making them difficult to identify. The comparative ESI-MS/MS study also revealed some characteristic peaks to differentiate different steroidal metabolites and can be useful for the unambiguous identification of anabolic steroids in biological fluid. Moreover, LC-ESI-MS/MS analysis of fermented extract of methyltestosterone, obtained by Macrophomina phaseolina was also investigated.

  10. Magnetic scavengers as carriers of analytes for flowing atmospheric pressure afterglow mass spectrometry (FAPA-MS).

    PubMed

    Cegłowski, Michał; Kurczewska, Joanna; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2015-09-01

    In this paper, a procedure for the preconcentration and transport of mixtures of acids, bases, and drug components to a mass spectrometer using magnetic scavengers is presented. Flowing atmospheric pressure afterglow mass spectrometry (FAPA-MS) was used as an analytical method for identification of the compounds by thermal desorption from the scavengers. The proposed procedure is fast and cheap, and does not involve time-consuming purification steps. The developed methodology can be applied for trapping harmful substances in minute quantities, to transport them to specialized, remotely located laboratories.

  11. Analysis of trace gases at ppb levels by proton transfer reaction mass spectrometry (PTR-MS)

    NASA Astrophysics Data System (ADS)

    Lindinger, W.; Hansel, A.

    1997-05-01

    A proton transfer reaction mass spectrometry (PTR-MS) system has been developed which allows for on-line measurements of trace gas components with concentrations as low as 1 ppb. The method is based on reactions of 0963-0252/6/2/004/img1 ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of medical applications by means of breath analysis, examples of environmental trace gas analysis and examples in the field of food chemistry demonstrate the wide applicability of the method.

  12. Use of Gas Chromatography-Mass Spectrometry (GC-MS) in Nonscience Major Course Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Kostecka, Keith S.; Lerman, Zafra M.; Angelos, Sanford A.

    1996-06-01

    Gas chromatography-mass spectrometry (GC-MS) has been utilized with nonscience majors in the courses: "Modern Methods in Science: Discovering Molecular Secrets"; "The Extraordinary Chemistry of Ordinary Things"; "From Ozone to Oil Spills: Chemistry, the Environment and You"; and "Crime Lab Chemistry: Solving Crime through Analytical Chemistry". Our efforts have centered on introducing prospective science communicators (film, video, radio, television, and journalism majors) to science relative to their majors and personal interests. Quality lecture-discussion topics, "mystery"-based laboratory activities have assisted in introducing and/or explaining specific areas of chemistry that attempt to reduce fear of subject matter. Students have also used GC-MS, as a form of alternative assessment, in course projects that have been based on their majors, personal interests, and cultural backgrounds. Students have also conducted advanced independent work in different areas of chemistry, including the analysis of nail polishes and lacquers and eleven aromatic compounds present in three different brands of gasoline.

  13. Monoacylglycerol Analysis Using MS/MSALL Quadruple Time of Flight Mass Spectrometry

    PubMed Central

    Gao, Fei; McDaniel, Justice; Chen, Emily Y.; Rockwell, Hannah; Lynes, Matthew D.; Tseng, Yu-Hua; Sarangarajan, Rangaprasad; Narain, Niven R.; Kiebish, Michael A.

    2016-01-01

    Monoacylglycerols (MAGs) are structural and bioactive metabolites critical for biological function. Development of facile tools for measuring MAG are essential to understand its role in different diseases and various pathways. A data-independent acquisition method, MS/MSALL, using electrospray ionization (ESI) coupled quadrupole time of flight mass spectrometry (MS), was utilized for the structural identification and quantitative analysis of individual MAG molecular species. Compared with other acylglycerols, diacylglycerols (DAG) and triacylglycerols (TAG), MAG characteristically presented as a dominant protonated ion, [M + H]+, and under low collision energy as fatty acid-like fragments due to the neutral loss of the glycerol head group. At low concentrations (<10 pmol/µL), where lipid-lipid interactions are rare, there was a strong linear correlation between ion abundance and MAG concentration. Moreover, using the MS/MSALL method the major MAG species from human plasma and mouse brown and white adipose tissues were quantified in less than 6 min. Collectively, these results demonstrate that MS/MSALL analysis of MAG is an enabling strategy for the direct identification and quantitative analysis of low level MAG species from biological samples with high throughput and sensitivity. PMID:27548241

  14. Protein turnover measurement using selected reaction monitoring-mass spectrometry (SRM-MS).

    PubMed

    Holman, Stephen W; Hammond, Dean E; Simpson, Deborah M; Waters, John; Hurst, Jane L; Beynon, Robert J

    2016-10-28

    Protein turnover represents an important mechanism in the functioning of cells, with deregulated synthesis and degradation of proteins implicated in many diseased states. Therefore, proteomics strategies to measure turnover rates with high confidence are of vital importance to understanding many biological processes. In this study, the more widely used approach of non-targeted precursor ion signal intensity (MS1) quantification is compared with selected reaction monitoring (SRM), a data acquisition strategy that records data for specific peptides, to determine if improved quantitative data would be obtained using a targeted quantification approach. Using mouse liver as a model system, turnover measurement of four tricarboxylic acid cycle proteins was performed using both MS1 and SRM quantification strategies. SRM outperformed MS1 in terms of sensitivity and selectivity of measurement, allowing more confident determination of protein turnover rates. SRM data are acquired using cheaper and more widely available tandem quadrupole mass spectrometers, making the approach accessible to a larger number of researchers than MS1 quantification, which is best performed on high mass resolution instruments. SRM acquisition is ideally suited to focused studies where the turnover of tens of proteins is measured, making it applicable in determining the dynamics of proteins complexes and complete metabolic pathways.This article is part of the themed issue 'Quantitative mass spectrometry'. PMID:27644981

  15. Triple Quadrupole Versus High Resolution Quadrupole-Time-of-Flight Mass Spectrometry for Quantitative LC-MS/MS Analysis of 25-Hydroxyvitamin D in Human Serum

    NASA Astrophysics Data System (ADS)

    Geib, Timon; Sleno, Lekha; Hall, Rabea A.; Stokes, Caroline S.; Volmer, Dietrich A.

    2016-08-01

    We describe a systematic comparison of high and low resolution LC-MS/MS assays for quantification of 25-hydroxyvitamin D3 in human serum. Identical sample preparation, chromatography separations, electrospray ionization sources, precursor ion selection, and ion activation were used; the two assays differed only in the implemented final mass analyzer stage; viz. high resolution quadrupole-quadrupole-time-of-flight (QqTOF) versus low resolution triple quadrupole instruments. The results were assessed against measured concentration levels from a routine clinical chemiluminescence immunoassay. Isobaric interferences prevented the simple use of TOF-MS spectra for extraction of accurate masses and necessitated the application of collision-induced dissociation on the QqTOF platform. The two mass spectrometry assays provided very similar analytical figures of merit, reflecting the lack of relevant isobaric interferences in the MS/MS domain, and were successfully applied to determine the levels of 25-hydroxyvitamin D for patients with chronic liver disease.

  16. Mass spectrometry of rhenium complexes: a comparative study by using LDI-MS, MALDI-MS, PESI-MS and ESI-MS.

    PubMed

    Petroselli, Gabriela; Mandal, Mridul Kanti; Chen, Lee Chuin; Ruiz, Gustavo T; Wolcan, Ezequiel; Hiraoka, Kenzo; Nonami, Hiroshi; Erra-Balsells, Rosa

    2012-03-01

    A group of rhenium (I) complexes including in their structure ligands such as CF(3)SO(3)-, CH(3)CO(2)-, CO, 2,2'-bipyridine, dipyridil[3,2-a:2'3'-c]phenazine, naphthalene-2-carboxylate, anthracene-9-carboxylate, pyrene-1-carboxylate and 1,10-phenanthroline have been studied for the first time by mass spectrometry. The probe electrospray ionization (PESI) is a technique based on electrospray ionization (ESI) that generates electrospray from the tip of a solid metal needle. In this work, mass spectra for organometallic complexes obtained by PESI were compared with those obtained by classical ESI and high flow rate electrospray ionization assisted by corona discharge (HF-ESI-CD), an ideal method to avoid decomposition of the complexes and to induce their oxidation to yield intact molecular cation radicals in gas state [M](+·) and to produce their reduction yielding the gas species [M](-·). It was found that both techniques showed in general the intact molecular ions of the organometallics studied and provided additional structure characteristic diagnostic fragments. As the rhenium complexes studied in the present work showed strong absorption in the UV-visible region, particularly at 355 nm, laser desorption ionization (LDI) mass spectrometry experiments could be conducted. Although intact molecular ions could be detected in a few cases, LDI mass spectra showed diagnostic fragments for characterization of the complexes structure. Furthermore, matrix-assisted laser desorption ionization (MALDI) mass spectra were obtained. Nor-harmane, a compound with basic character, was used as matrix, and the intact molecular ions were detected in two examples, in negative ion mode as the [M](-·) species. Results obtained with 2-[(2E)-3-(4-tert-buthylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) as matrix are also described. LDI experiments provided more information about the rhenium complex structures than did the MALDI ones.

  17. {sup 99}Tc bioassay by inductively coupled plasma mass spectrometry (ICP-MS)

    SciTech Connect

    Lewis, L.A.

    1998-05-01

    A means of analyzing {sup 99}Tc in urine by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. Historically, {sup 99}Tc analysis was based on the radiometric detection of the 293 keV E{sub Max} beta decay product by liquid scintillation or gas flow proportional counting. In a urine matrix, the analysis of{sup 99}Tc is plagued with many difficulties using conventional radiometric methods. Difficulties originate during chemical separation due to the volatile nature of Tc{sub 2}O{sub 7} or during radiation detection due to color or chemical quenching. A separation scheme for {sup 99}Tc detection by ICP-MS is given and is proven to be a sensitive and robust analytical alternative. A comparison of methods using radiometric and mass quantitation of {sup 99}Tc has been conducted in water, artificial urine, and real urine matrices at activity levels between 700 and 2,200 dpm/L. Liquid scintillation results based on an external standard quench correction and a quench curve correction method are compared to results obtained by ICP-MS. Each method produced accurate results, however the precision of the ICP-MS results is superior to that of liquid scintillation results. Limits of detection (LOD) for ICP-MS and liquid scintillation detection are 14.67 and 203.4 dpm/L, respectively, in a real urine matrix. In order to determine the basis for the increased precision of the ICP-MS results, the detection sensitivity for each method is derived and measured. The detection sensitivity for the {sup 99}Tc isotope by ICP-MS is 2.175 x 10{sup {minus}7} {+-} 8.990 x 10{sup {minus}9} and by liquid scintillation is 7.434 x 10{sup {minus}14} {+-} 7.461 x 10{sup {minus}15}. A difference by seven orders of magnitude between the two detection systems allows ICP-MS samples to be analyzed for a period of 15 s compared to 3,600 s by liquid scintillation counting with a lower LOD.

  18. High performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry for V and Ni quantification as tetrapyrroles

    NASA Astrophysics Data System (ADS)

    Duyck, Christiane Béatrice; Saint'Pierre, Tatiana Dillenburg; Miekeley, Norbert; da Fonseca, Teresa Cristina Oliveira; Szatmari, Peter

    2011-05-01

    A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 μg L - 1 and 8 μg L - 1 . The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

  19. Comparison of copper labeling followed by liquid chromatography-inductively coupled plasma mass spectrometry and immunochemical assays for serum hepcidin-25 determination.

    PubMed

    Konz, Tobias; Alonso-García, Javier; Montes-Bayón, María; Sanz-Medel, Alfredo

    2013-10-17

    Hepcidin-25 has been defined as the key biomarker in iron metabolism. This peptide binds to the iron transporter ferroportin to cause its degradation. Therefore, the need for specific, accurate and precise methods for the quantification of hepcidin-25 in biological fluids is dramatically increasing. In this regard, the use of rapid immunochemical methods that provide low limit of quantification is desired for routine clinical use. However, such fast methodologies should be first analytically evaluated and compared with alternative strategies to check for their advantages and limitations. Here we compare the use of a commercial immunochemical assay for hepcidin determination with a novel analytical approach based on Cu-labeling of the peptide followed by Cu determination using liquid chromatography (HPLC) and plasma mass spectrometry (ICP-MS). The figures of merit of both systems reveal similar analytical characteristics and both seem to be adequate for the determination of the peptide at biologically relevant concentrations in human serum samples. The analysis of a larger number of samples (n=50) by both techniques showed a good agreement in the concentrations found. Such finding permits to address the hepcidin recovery in the sample preparation procedure necessary for the HPLC-ICP-MS analysis in human serum that turn out to be 76-85%. Additionally, limitations due to cross-reactivity issues of the ELISA method could be addressed in some of the samples by using LC-ICP-MS and were confirmed by LC-Electrospray-MS.

  20. LC-IMS-MS Feature Finder. Detecting Multidimensional Liquid Chromatography, Ion Mobility, and Mass Spectrometry Features in Complex Datasets

    SciTech Connect

    Crowell, Kevin L.; Slysz, Gordon W.; Baker, Erin Shammel; Lamarche, Brian L.; Monroe, Matthew E.; Ibrahim, Yehia M.; Payne, Samuel H.; Anderson, Gordon A.; Smith, Richard D.

    2013-09-05

    We introduce a command line software application LC-IMS-MS Feature Finder that searches for molecular ion signatures in multidimensional liquid chromatography-ion mobility spectrometry-mass spectrometry (LC-IMS-MS) data by clustering deisotoped peaks with similar monoisotopic mass, charge state, LC elution time, and ion mobility drift time values. The software application includes an algorithm for detecting and quantifying co-eluting chemical species, including species that exist in multiple conformations that may have been separated in the IMS dimension.

  1. Chemical profile of mango (Mangifera indica L.) using electrospray ionisation mass spectrometry (ESI-MS).

    PubMed

    Oliveira, Bruno G; Costa, Helber B; Ventura, José A; Kondratyuk, Tamara P; Barroso, Maria E S; Correia, Radigya M; Pimentel, Elisângela F; Pinto, Fernanda E; Endringer, Denise C; Romão, Wanderson

    2016-08-01

    Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention. PMID:26988473

  2. Chemical profile of mango (Mangifera indica L.) using electrospray ionisation mass spectrometry (ESI-MS).

    PubMed

    Oliveira, Bruno G; Costa, Helber B; Ventura, José A; Kondratyuk, Tamara P; Barroso, Maria E S; Correia, Radigya M; Pimentel, Elisângela F; Pinto, Fernanda E; Endringer, Denise C; Romão, Wanderson

    2016-08-01

    Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention.

  3. Analysis of thyroid hormones in serum of Baikal seals and humans by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay methods: application of the LC-MS/MS method to wildlife tissues.

    PubMed

    Kunisue, Tatsuya; Eguchi, Akifumi; Iwata, Hisato; Tanabe, Shinsuke; Kannan, Kurunthachalam

    2011-12-01

    Thyroid hormones (THs) are essential for the regulation of growth and development in both humans and wildlife. Until recently, TH concentrations in the tissues of animals have been examined by immunoassay (IA) methods. IA methods are sensitive, but for TH analysis, they are compromised by a lack of adequate specificity. In this study, we determined the concentrations of six THs, L-thyroxine (T(4)), 3,3',5-triiodo-L-thyronine (T(3)), 3,3',5'-triiodo-L-thyronine (rT(3)), 3,5-diiodo-L-thyronine (3,5-T(2)), 3,3'-diiodo-L-thyronine (3,3'-T(2)), and 3-iodo-L-thyronine (3-T(1)), in the serum of humans (n = 79) and wild Baikal seals (n = 37), by isotope ([(13)C(6)]-T(4))-dilution liquid chromatography (LC)-tandem mass spectrometry (MS/MS), and compared the TH levels with those measured by an electrochemiluminescent immunoassay (ECLIA) method. T(3) and T(4) were detected in all serum samples of both humans and Baikal seals, whereas T(1), 3,3'-T(2), and 3,5-T(2) were below the limit of detection (LOD). rT(3) was detected in Baikal seal sera at concentrations higher than T(3) in 28 seal samples, indicating an anomaly in deiodinase activity in Baikal seals. In humans, regression analyses of TH concentrations, measured by ECLIA and LC-MS/MS methods, showed significant correlations for T(4) (r = 0.852) and T(3) (r = 0.676; after removal of a serum sample with abnormal T(3) levels). In Baikal seals, a low correlation coefficient (r = 0.466) for T(4) levels and no correlation for T(3) levels (p = 0.093) were found between ECLIA and LC-MS/MS methods. These results suggest that interference by a nonspecific reaction against anti-T(3) and anti-T(4) antibodies used in the ECLIA can contribute to inaccuracies in TH measurement in Baikal seals. When the relationship between concentrations of THs in sera and dioxin-like toxic equivalents in blubber samples of Baikal seals (n = 19) was examined, a significantly negative correlation was found for serum T(4) levels measured by the LC-MS/MS

  4. The bridge between thin layer chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry: The realization of liquid thin layer chromatography-mass spectrometry (LTLC-MS).

    PubMed

    Li, Yafeng; Wang, Jianing; Zhan, Lingpeng; Wleklinski, Michael; Wang, Jiyun; Xiong, Caiqiao; Liu, Huihui; Zhou, Yueming; Nie, Zongxiu

    2016-08-19

    The combination of thin layer chromatography (TLC) and mass spectrometry (MS) has been studied for decades, but for most cases MS detection is done after TLC separation is finished. Here, an online simultaneous TLC-MS analysis system, liquid thin layer chromatography-mass spectrometry (LTLC-MS), is developed which successfully synchronize TLC separation process and MS detection process like GC-MS and HPLC-MS do. And there's no need to use specially designed TLC, just regular TLC plates are enough. LTLC-MS method is composed of a newly developed ambient ionization method, glow discharge-matrix assisted infrared desorption ionization (GD-MAIRDI), and forced-flow TLC (FFTLC) technique, which guarantees the MS detection process does not disturb the TLC separation process throughout the whole analysis. The whole LTLC-MS analysis only need two steps and less than 15min. Mixtures as well as the two main components of a pain relief pills have been successfully analyzed by LTLC-MS. This proof of concept study opens up new possibilities of combining TLC with MS, and will further broaden the application abilities of TLC. PMID:27452991

  5. The future of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discovery

    PubMed Central

    Metz, Thomas O.; Zhang, Qibin; Page, Jason S.; Shen, Yufeng; Callister, Stephen J.; Jacobs, Jon M.; Smith, Richard D.

    2008-01-01

    SUMMARY The future utility of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discover will be discussed, beginning with a brief description of the evolution of metabolomics and the utilization of the three most popular analytical platforms in such studies: NMR, GC-MS, and LC-MS. Emphasis is placed on recent developments in high-efficiency LC separations, sensitive electrospray ionization approaches, and the benefits to incorporating both in LC-MS-based approaches. The advantages and disadvantages of various quantitative approaches are reviewed, followed by the current LC-MS-based tools available for candidate biomarker characterization and identification. Finally, a brief prediction on the future path of LC-MS-based methods in metabolic profiling and metabolomic studies is given. PMID:19177179

  6. Determination of multiple mycotoxins in dietary supplements containing green coffee bean extracts using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).

    PubMed

    Vaclavik, Lukas; Vaclavikova, Marta; Begley, Timothy H; Krynitsky, Alexander J; Rader, Jeanne I

    2013-05-22

    An ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of 34 mycotoxins in dietary supplements containing green coffee bean (GCB) extracts was developed, evaluated, and used in the analysis of 50 commercial products. A QuEChERS-like procedure was used for isolation of target analytes from the examined matrices. Average recoveries of the analytes were in the range of 75-110%. The precision of the method expressed as relative standard deviation was below 12%. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 1.0 to 50.0 μg/kg and from 2.5 to 100 μg/kg, respectively. Due to matrix effects, the method of standard additions was used to ensure accurate quantitation. Ochratoxin A, ochratoxin B, fumonisin B1 and mycophenolic acid were found in 36%, 32%, 10%, and 16% of tested products, respectively. Mycotoxins occurred in the following concentration ranges: ochratoxin A, <1.0-136.9 μg/kg; ochratoxin B, <1.0-20.2 μg/kg; fumonisin B1, <50.0-415.0 μg/kg; mycophenolic acid, <5.0-395.0 μg/kg. High-resolution mass spectrometry operated in full MS and MS/MS mode was used to confirm the identities of the reported compounds.

  7. Simple quantitative determination of potent thiols at ultratrace levels in wine by derivatization and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis.

    PubMed

    Capone, Dimitra L; Ristic, Renata; Pardon, Kevin H; Jeffery, David W

    2015-01-20

    Volatile sulfur compounds contribute characteristic aromas to foods and beverages and are widely studied, because of their impact on sensory properties. Certain thiols are particularly important to the aromas of roasted coffee, cooked meat, passion fruit, grapefruit, and guava. These same thiols enhance the aroma profiles of different wine styles, imparting pleasant aromas reminiscent of citrus and tropical fruits (due to 3-mercaptohexan-1-ol, 3-mercaptohexyl acetate, 4-mercapto-4-methylpentan-2-one), roasted coffee (2-furfurylthiol), and struck flint (benzyl mercaptan), at nanogram-per-liter levels. In contrast to the usual gas chromatography (GC) approaches, a simple and unique high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for routine analysis of five wine thiols, using 4,4'-dithiodipyridine (DTDP) as a derivatizing agent and polydeuterated internal standards for maximum accuracy and precision. DTDP reacted rapidly with thiols at wine pH and provided stable derivatives, which were enriched by solid-phase extraction (SPE) prior to analysis by HPLC-MS/MS. All steps were optimized and the method was validated in different wine matrices, with method performance being comparable to a well-optimized but more cumbersome gas chromatography-mass spectrometry (GC-MS) method. A range of commercial wines was analyzed with the new method, revealing the distribution of the five thiols in white, red, rosé, and sparkling wine styles.

  8. Determination of starch lysophospholipids in rice using liquid chromatography-mass spectrometry (LC-MS).

    PubMed

    Liu, Lei; Tong, Chuan; Bao, Jinsong; Waters, Daniel L E; Rose, Terry J; King, Graham J

    2014-07-16

    Acquiring a complete understanding of rice starch lysophospholipids (LPLs), their biosynthetic pathways and genetic diversity, and the influence of genotype by environment interactions has been hampered by the lack of efficient high-throughput extraction and analysis methods. It was hypothesized a single-step aqueous n-propanol extraction combined with liquid chromatography-mass spectrometry (LC-MS) could be employed to analyze starch LPLs in white rice. The investigation found different grinding methods showed little effect on the final LPL detected, and a simple single-step extraction with 75% n-propanol (8 mL/0.15 g) heated at 100 °C for 2 h was as effective as an onerous multistep extraction method. A LC-MS method was optimized to simultaneously quantify 10 major LPLs in rice starch within 15 min. This method enables total and individual starch LPL analysis of a large number of rice samples at little cost. This approach could be applied to starch LPLs in other cereals.

  9. Differentiation of linear and cyclic polymer architectures by MALDI tandem mass spectrometry (MALDI-MS2).

    PubMed

    Yol, Aleer M; Dabney, David E; Wang, Shih-Fan; Laurent, Boyd A; Foster, Mark D; Quirk, Roderic P; Grayson, Scott M; Wesdemiotis, Chrys

    2013-01-01

    [M + Ag](+) ions from cyclic and linear polystyrenes and polybutadienes, formed by matrix-assisted laser desorption ionization (MALDI), give rise to significantly different fragmentation patterns in tandem mass spectrometry (MS(2)) experiments. In both cases, fragmentation starts with homolytic cleavage at the weakest bond, usually a C-C bond, to generate two radicals. From linear structures, the separated radicals depolymerize extensively by monomer losses and backbiting rearrangements, leading to low-mass radical ions and much less abundant medium- and high-mass closed-shell fragments that contain one of the original end groups, along with internal fragments. With cyclic structures, depolymerization is less efficient, as it can readily be terminated by intramolecular H-atom transfer between the still interconnected radical sites (disproportionation). These differences in fragmentation reactivity result in substantially different fragment ion distributions in the MS(2) spectra. Simple inspection of the relative intensities of low- versus high-mass fragments permits conclusive determination of the macromolecular architecture, while full spectral interpretation reveals the individual end groups of linear polymers or the identity of the linker used to form the cyclic polymer. PMID:23192702

  10. Urinary Succinylacetone Analysis by Gas Chromatography-Mass Spectrometry (GC-MS).

    PubMed

    Chen, Hongjie; Yu, Chunli

    2016-01-01

    Succinylacetone (SA) is used for the diagnosis and monitoring of patients with tyrosinemia type I (Tyr I). SA is exclusively elevated in blood and urine of patients with Tyr I. As urinary SA concentration is much higher than blood, SA is usually tested in urine samples. Urinary SA quantitation by gas chromatography mass spectrometry (GC-MS) is described in this chapter. The urine sample in the amount of 1 μmol creatinine is used for testing. 3,4,5,6,7-(13)C5-succinylacetone ((13)C5-SA) is used as an internal standard (IS). SA and (13)C5-SA are oximated and extracted from urine with organic solvents, and then derivatized to form trimethylsilane (TMS) derivatives. TMS derivatives of SA and (13)C5-SA are detected and quantified by GC-MS using selective ion monitoring (SIM). The assay is linear from 0.05 to 450 mmol/mol creatinine to cover the broad range of urinary SA concentrations.

  11. Differentiation of Linear and Cyclic Polymer Architectures by MALDI Tandem Mass Spectrometry (MALDI-MS2)

    NASA Astrophysics Data System (ADS)

    Yol, Aleer M.; Dabney, David E.; Wang, Shih-Fan; Laurent, Boyd A.; Foster, Mark D.; Quirk, Roderic P.; Grayson, Scott M.; Wesdemiotis, Chrys

    2013-01-01

    [M + Ag]+ ions from cyclic and linear polystyrenes and polybutadienes, formed by matrix-assisted laser desorption ionization (MALDI), give rise to significantly different fragmentation patterns in tandem mass spectrometry (MS2) experiments. In both cases, fragmentation starts with homolytic cleavage at the weakest bond, usually a C-C bond, to generate two radicals. From linear structures, the separated radicals depolymerize extensively by monomer losses and backbiting rearrangements, leading to low-mass radical ions and much less abundant medium- and high-mass closed-shell fragments that contain one of the original end groups, along with internal fragments. With cyclic structures, depolymerization is less efficient, as it can readily be terminated by intramolecular H-atom transfer between the still interconnected radical sites (disproportionation). These differences in fragmentation reactivity result in substantially different fragment ion distributions in the MS2 spectra. Simple inspection of the relative intensities of low- versus high-mass fragments permits conclusive determination of the macromolecular architecture, while full spectral interpretation reveals the individual end groups of linear polymers or the identity of the linker used to form the cyclic polymer.

  12. Metabolic profile of naringenin in the stomach and colon using liquid chromatography/electrospray ionization linear ion trap quadrupole-Orbitrap-mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) and LC-ESI-MS/MS.

    PubMed

    Orrego-Lagarón, Naiara; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Lamuela-Raventos, Rosa M; Escribano-Ferrer, Elvira

    2016-02-20

    Several biological activities (antioxidant, anti-inflammatory, anticarcinogenic) are attributed to naringenin (NAR)-a predominant flavonoid of citrus fruit and tomato-despite its low bioavailability after ingestion. NAR undergoes extensive metabolism when crossing the gastrointestinal tract, resulting in enteric, hepatic and microbial metabolites, some of them with recognized beneficial effects on human health. This study sought to provide new insights into the metabolism of NAR in regions of the gastrointestinal tract where it has been less studied: the stomach and colon. With this purpose, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique (LC-ESI-LTQ-Orbitrap-MS) was used for an accurate identification of NAR metabolites, and liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole was used for their identification and quantification. The combination of both analytical techniques provided a broader metabolic profile of NAR. As far as we know, this is the first in-depth metabolic profiling study of NAR in the stomach of mice. Three of the metabolites determined using the LC-LTQ-Orbitrap could not be identified by LC-ESI-MS/MS in stomach perfusion samples: apigenin, 3-(4-hydroxyphenyl) propionic acid and phloroglucinol. The number of colonic metabolites determined using the LTQ-Orbitrap-MS was more than twice the number identified by LC-ESI-MS/MS.

  13. Metabolic profile of naringenin in the stomach and colon using liquid chromatography/electrospray ionization linear ion trap quadrupole-Orbitrap-mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) and LC-ESI-MS/MS.

    PubMed

    Orrego-Lagarón, Naiara; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Lamuela-Raventos, Rosa M; Escribano-Ferrer, Elvira

    2016-02-20

    Several biological activities (antioxidant, anti-inflammatory, anticarcinogenic) are attributed to naringenin (NAR)-a predominant flavonoid of citrus fruit and tomato-despite its low bioavailability after ingestion. NAR undergoes extensive metabolism when crossing the gastrointestinal tract, resulting in enteric, hepatic and microbial metabolites, some of them with recognized beneficial effects on human health. This study sought to provide new insights into the metabolism of NAR in regions of the gastrointestinal tract where it has been less studied: the stomach and colon. With this purpose, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique (LC-ESI-LTQ-Orbitrap-MS) was used for an accurate identification of NAR metabolites, and liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole was used for their identification and quantification. The combination of both analytical techniques provided a broader metabolic profile of NAR. As far as we know, this is the first in-depth metabolic profiling study of NAR in the stomach of mice. Three of the metabolites determined using the LC-LTQ-Orbitrap could not be identified by LC-ESI-MS/MS in stomach perfusion samples: apigenin, 3-(4-hydroxyphenyl) propionic acid and phloroglucinol. The number of colonic metabolites determined using the LTQ-Orbitrap-MS was more than twice the number identified by LC-ESI-MS/MS. PMID:26698229

  14. Calibration and intercomparison of acetic acid measurements using proton transfer reaction mass spectrometry (PTR-MS)

    USGS Publications Warehouse

    Haase, K.B.; Keene, W.C.; Pszenny, A.A.P.; Mayne, H.R.; Talbot, R.W.; Sive, B.C.

    2012-01-01

    Acetic acid is one of the most abundant organic acids in the ambient atmosphere, with maximum mixing ratios reaching into the tens of parts per billion by volume (ppbv) range. The identities and associated magnitudes of the major sources and sinks for acetic acid are poorly characterized, due in part to the limitation in available measurement techniques. This paper demonstrates that Proton Transfer Reaction Mass Spectrometry (PTR-MS) can reliably quantify acetic acid vapor in ambient air. Three different PTR-MS configurations were calibrated at low ppbv mixing ratios using permeation tubes, which yielded calibration factors between 7.0 and 10.9 normalized counts per second per ppbv (ncps ppbv−1) at a drift tube field strength of 132 townsend (Td). Detection limits ranged from 0.06 to 0.32 ppbv with dwell times of 5 s. These calibration factors showed negligible humidity dependence. Using the experimentally determined calibration factors, PTR-MS measurements of acetic acid during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign were validated against results obtained using Mist Chambers coupled with Ion Chromatography (MC/IC). An orthogonal least squares linear regression of paired data yielded a slope of 1.14 ± 0.06 (2σ), an intercept of 0.049 ± 20 (2σ) ppbv, and an R2 of 0.78. The median mixing ratio of acetic acid on Appledore Island, ME during the ICARTT campaign was 0.530 ± 0.025 ppbv with a minimum of 0.075 ± 0.004 ppbv, and a maximum of 3.555 ± 0.171 ppbv.

  15. Determination of organic and inorganic mercury species in water and sediment samples by HPLC on-line coupled with ICP-MS.

    PubMed

    dos Santos, José Soares; de la Guárdia, Miguel; Pastor, Augustin; dos Santos, Maria Lúcia Pires

    2009-11-15

    This paper describes a preconcentration method for Hg(2+) and MeHg(+) in water samples using sodium diethyldithiocarbamate immobilized in polyurethane foam (PU-NaDDC) and an extraction method for several mercury species in sediment samples, including MeHg(+), EtHg(+) and PhHg(+), which is simple, rapid, and uses a single organic solvent. Separation and measurement were done by high-performance liquid chromatography on-line with inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Initially, the test of recovery was applied using procedures compatible with HPLC. Under the optimum extraction conditions, recoveries of 96.7, 96.3 and 97.3% were obtained for MeHg(+), EtHg(+), and PhHg(+), respectively, from n=4 spiked sediment samples. This study also demonstrates that the combination of solid-phase extraction on PU-NaDDC with HPLC separation and ICP-MS detection is an effective preconcentration procedure for simultaneous measurement of Hg(2+) and MeHg(+) at ultra-trace levels in water samples. The application of the proposed procedure to the determination of mercury species in drinking water sample was investigated. The proposed method clearly gave satisfactory average recoveries between 93.7 and 101.5%.

  16. Identification and quantitation of cocaine, benzoylecgonine, and cocaethylene in blood, serum, and plasma using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS).

    PubMed

    Kriger, Scott; Gunn, Josh; Terrell, Andrea R

    2010-01-01

    Cocaine is a widely abused stimulant. Numerous methods exist for the identification of the drug, or more commonly, one of its metabolites in urine. Urine testing is useful for most cases, but it is necessary to use other matrices in forensic situations and when subjects are anuric. We describe a novel method for the analysis of cocaine, benzoylecgonine, and cocaethylene in blood, serum, and plasma utilizing ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Sample preparation has been minimized to a simple deproteinization step in which each specimen is mixed with an acetonitrile-internal standard mixture. The method has excellent precision across the linear range of 25-2,000 ng/mL for each analyte. With a run-time of 4 min, this method provides a significant improvement over traditional GC/MS methods. PMID:20077068

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

    PubMed

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

    2016-09-01

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

  18. [Interest and limits of inductively coupled plasma mass spectrometry (ICP-MS) for urinary diagnosis of radionuclide internal contamination].

    PubMed

    Lecompte, Yannick; Bohand, Sandra; Laroche, Pierre; Cazoulat, Alain

    2013-01-01

    After a review of radiometric reference methods used in radiotoxicology, analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) for the workplace urinary diagnosis of internal contamination by radionuclides are evaluated. A literature review (covering the period from 2000 to 2012) is performed to identify the different applications of ICP-MS in radiotoxicology for urine analysis. The limits of detection are compared to the recommendations of the International commission on radiological protection (ICRP 78: "Individual monitoring for internal exposure of workers"). Except one publication describing the determination of strontium-90 (β emitter), all methods using ICP-MS reported in the literature concern actinides (α emitters). For radionuclides with a radioactive period higher than 10(4) years, limits of detection are most often in compliance with ICRP publication 78 and frequently lower than radiometric methods. ICP-MS allows the specific determination of plutonium-239 + 240 isotopes which cannot be discriminated by α spectrometry. High resolution ICP-MS can also measure uranium isotopic ratios in urine for total uranium concentrations lower than 20 ng/L. The interest of ICP-MS in radiotoxicology concerns essentially the urinary measurement of long radioactive period actinides, particularly for uranium isotope ratio determination and 239 and 240 plutonium isotopes discrimination. Radiometric methods remain the most efficient for the majority of other radionuclides.

  19. [Interest and limits of inductively coupled plasma mass spectrometry (ICP-MS) for urinary diagnosis of radionuclide internal contamination].

    PubMed

    Lecompte, Yannick; Bohand, Sandra; Laroche, Pierre; Cazoulat, Alain

    2013-01-01

    After a review of radiometric reference methods used in radiotoxicology, analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) for the workplace urinary diagnosis of internal contamination by radionuclides are evaluated. A literature review (covering the period from 2000 to 2012) is performed to identify the different applications of ICP-MS in radiotoxicology for urine analysis. The limits of detection are compared to the recommendations of the International commission on radiological protection (ICRP 78: "Individual monitoring for internal exposure of workers"). Except one publication describing the determination of strontium-90 (β emitter), all methods using ICP-MS reported in the literature concern actinides (α emitters). For radionuclides with a radioactive period higher than 10(4) years, limits of detection are most often in compliance with ICRP publication 78 and frequently lower than radiometric methods. ICP-MS allows the specific determination of plutonium-239 + 240 isotopes which cannot be discriminated by α spectrometry. High resolution ICP-MS can also measure uranium isotopic ratios in urine for total uranium concentrations lower than 20 ng/L. The interest of ICP-MS in radiotoxicology concerns essentially the urinary measurement of long radioactive period actinides, particularly for uranium isotope ratio determination and 239 and 240 plutonium isotopes discrimination. Radiometric methods remain the most efficient for the majority of other radionuclides. PMID:23747664

  20. Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species

    DOE PAGESBeta

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; et al

    2016-07-25

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS–MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS–MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI–IMS–MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambientmore » field campaign in the forested SE US. The ambient IMS–MS signals are consistent with laboratory IMS–MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS–MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS–MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of

  1. Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS for isotope analysis of long-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Becker, J. Sabine

    2005-04-01

    For a few years now inductively coupled plasma mass spectrometry has been increasingly used for precise and accurate determination of isotope ratios of long-lived radionuclides at the trace and ultratrace level due to its excellent sensitivity, good precision and accuracy. At present, ICP-MS and also laser ablation ICP-MS are applied as powerful analytical techniques in different fields such as the characterization of nuclear materials, recycled and by-products (e.g., spent nuclear fuel or depleted uranium ammunitions), radioactive waste control, in environmental monitoring and in bioassay measurements, in health control, in geochemistry and geochronology. Especially double-focusing sector field ICP mass spectrometers with single ion detector or with multiple ion collector device have been used for the precise determination of long-lived radionuclides isotope ratios at very low concentration levels. Progress has been achieved by the combination of ultrasensitive mass spectrometric techniques with effective separation and enrichment procedures in order to improve detection limits or by the introduction of the collision cell in ICP-MS for reducing disturbing interfering ions (e.g., of 129Xe+ for the determination of 129I). This review describes the state of the art and the progress of ICP-MS and laser ablation ICP-MS for isotope ratio measurements of long-lived radionuclides in different sample types, especially in the main application fields of characterization of nuclear and radioactive waste material, environmental research and health controls.

  2. Direct Analysis in Real Time Mass Spectrometry (DART-MS) of Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Mazzotta, Michael G.; Pace, Robert B.; Wallgren, Brandy N.; Morton, Samuel A.; Miller, Kevin M.; Smith, Darrin L.

    2013-10-01

    Direct analysis in real time mass spectrometry (DART-MS) was used to analyze ionic liquids (ILs) containing either imidazolium or phosphonium cations combined with different types of inorganic and organic anions. Ionic liquids were directly inserted into the ionization source using a glass probe without dissolution into organic solvents. Mass spectra of the ILs were collected in both positive and negative mode with a linear ion-trap instrument. The intact cation of the compound was typically the dominant peak in positive mass spectra and cluster ion formation was present. Some individual anions were not readily observed in the negative mass spectra (based on the type of anion); however, the mass difference of adjacent cluster ions equal the mass of a complete IL and the anion mass could be verified by subtracting the known cation mass. The degree and intensity of the cluster ion formations was found to be dependent on the nature of the specific ILs as well as the DART temperature gas stream.

  3. [Screening and identification of forensic molecular markers of injury using MALDI-TOF-MS imaging mass spectrometry].

    PubMed

    Liu, Ning-Guo; Chen, Yi-Jiu

    2014-10-01

    There are many deficiencies in forensic traumatic molecular markers detected by the techniques of traditional immunohistology and molecular biology, because these markers are isolated and obscure of the mechanism of interaction. The imaging mass spectrometry (IMS) is more suitable for the forensic molecular markers using function of screening, analysis and graphical representation. In this paper, the techniques and the latest research in screening and identification of typical molecular markers by IMS based on matrix-assisted laser adsorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) are reviewed. And its application values in forensic injury are discussed.

  4. Quantitation of fluoroquinolones in honey using tandem mass spectrometry (LC-MS/MS): nested validation with two mass spectrometers.

    PubMed

    Durden, David A; Fernandes, Gwen

    2010-01-01

    A number of drugs in the quinolone and fluoroquinolone families, approved for veterinary treatment of food animals by various countries, may be used to treat bee diseases and thereby contaminate honey. An LC-MS/MS method has been developed for the quantification of the quinolones: flumequine, nalidixic acid, oxolinic acid, and pipemidic acid; and the fluoroquinolones ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, norfloxacin, ofloxacin, orbifloxacin, marbofloxacin, sarafloxacin, and sparfloxacin. A method-matched calibration curve is used with several internal standards, i.e., ciprofloxacin-d8, Iomefloxacin, and cinoxacin, to correct for the various types of honey matrices: white, light, medium, and dark colors. Enoxacin is added as an external recovery standard. The LOD values range from 0.05 microg/kg (ofloxacin) to 0.4 microg/kg (flumequine). The compounds are verified by LC-MS/MS retention times and ion ratios. Method uncertainty was determined using two separate analytical systems. The method has successfully measured the presence of norfloxacin in several samples of honey imported into Canada.

  5. Using ProHits to store, annotate and analyze affinity purification - mass spectrometry (AP-MS) data

    PubMed Central

    Liu, Guomin; Zhang, Jianping; Choi, Hyungwon; Lambert, Jean-Philippe; Srikumar, Tharan; Larsen, Brett; Nesvizhskii, Alexey I.; Raught, Brian; Tyers, Mike; Gingras, Anne-Claude

    2012-01-01

    Affinity purification coupled with mass spectrometry (AP-MS) is a robust technique used to identify protein-protein interactions. With recent improvements in sample preparation, and dramatic advances in MS instrumentation speed and sensitivity, this technique is becoming more widely used throughout the scientific community. To meet the needs of research groups both large and small, we have developed software solutions for tracking, scoring and analyzing AP-MS data. Here, we provide details for the installation and utilization of ProHits, a Laboratory Information Management System designed specifically for AP-MS interaction proteomics. This protocol explains: (i) how to install the complete ProHits system, including modules for the management of mass spectrometry files and the analysis of interaction data, and (ii) alternative options for the use of pre-existing search results in simpler versions of ProHits, including a virtual machine implementation of our ProHits Lite software. We also describe how to use the main features of the software to analyze AP-MS data. PMID:22948730

  6. Towards absolute quantification of therapeutic monoclonal antibody in serum by LC-MS/MS using isotope-labeled antibody standard and protein cleavage isotope dilution mass spectrometry.

    PubMed

    Heudi, Olivier; Barteau, Samuel; Zimmer, Dieter; Schmidt, Joerg; Bill, Kurt; Lehmann, Natalie; Bauer, Christian; Kretz, Olivier

    2008-06-01

    Although LC-MS methods are increasingly used for the absolute quantification of proteins, the lack of appropriate internal standard (IS) hinders the development of rapid and standardized analytical methods for both in vitro and in vivo studies. Here, we have developed a novel method for the absolute quantification of a therapeutic protein, which is monoclonal antibody (mAb). The method combines liquid chromatography tandem mass spectrometry (LC-MS/MS) and protein cleavage isotope dilution mass spectrometry with the isotope-labeled mAb as IS. The latter was identical to the analyzed mAb with the exception that each threonine contains four (13)C atoms and one (15)N atom. Serum samples were spiked with IS prior to the overnight trypsin digestion and subsequent sample cleanup. Sample extracts were analyzed on a C18 ACE column (150 mm x 4.6 mm) using an LC gradient time of 11 min. Endogenous mAb concentrations were determined by calculating the peak height ratio of its signature peptide to the corresponding isotope-labeled peptide. The linear dynamic range was established between 5.00 and 1000 microg/mL mAb with accuracy and precision within +/-15% at all concentrations and below +/-20% at the LLOQ (lower limit of quantification). The overall method recovery in terms of mAb was 14%. The losses due to sample preparation (digestion and purification) were 72% from which about 32% was due to the first step of the method, the sample digestion. This huge loss during sample preparation strongly emphasizes the necessity to employ an IS right from the beginning. Our method was successfully applied to the mAb quantification in marmoset serum study samples, and the precision obtained on duplicate samples was, in most cases, below 20%. The comparison with enzyme-linked immunosorbent assay (ELISA) showed higher exposure in terms of AUC and Cmax with the LC-MS/MS method. Possible reasons for this discrepancy are discussed in this study. The results of this study indicate that our LC-MS/MS

  7. Liquid chromatography-tandem mass spectrometry (LC/APCI-MS/MS) methods for the quantification of captan and folpet phthalimide metabolites in human plasma and urine.

    PubMed

    Berthet, Aurélie; Bouchard, Michèle; Schüpfer, Patrick; Vernez, David; Danuser, Brigitta; Huynh, Cong Khanh

    2011-02-01

    Captan and folpet are fungicides largely used in agriculture. They have similar chemical structures, except that folpet has an aromatic ring unlike captan. Their half-lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide (THPI) and phthalimide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted either by gas chromatography coupled to mass spectrometry or liquid chromatography with UV detection. The objective of this study was thus to develop simple, sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI was added as an internal standard and purification was performed by solid-phase extraction followed by LC/APCI-MS/MS analysis in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers exposed to captan or folpet. The methods showed a good linearity (R (2) > 0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%), and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively, for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human plasma and urine.

  8. Observation of T-2 Toxin and HT-2 Toxin Glucosides from Fusarium sporotrichioides by Liquid Chromatography Coupled to Tandem Mass Spectrometry (LC-MS/MS)

    PubMed Central

    Busman, Mark; Poling, Stephen M.; Maragos, Chris M.

    2011-01-01

    The trichothecenes produced by solid and liquid cultures of Fusarium sporotrichioides were evaluated with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Along with the expected T-2 toxin HT-2 toxin and neosolaniol, two additional compounds were detected, which had ions 162 m/z higher than those in the mass spectra of T-2 toxin or HT-2 toxin. Fragmentation behavior of these two compounds was similar to that of T-2 toxin and HT-2 toxin. Based on LC-MS/MS behavior, it is proposed that the two compounds are T-2 toxin 3-O-glucoside and HT-2 toxin 3-O-glucoside. Production of the two glucosides was measured in kernels from wheat and oat inoculated with F. sporotrichiodes, as well as in cultures grown in liquid media and on cracked corn or rice. Production of glucosides in wheat and oats suggest that they may also be present in naturally contaminated cereals. PMID:22295176

  9. Analysing persistent organic pollutants in eggs, blood and tissue of the green sea turtle (Chelonia mydas) using gas chromatography with tandem mass spectrometry (GC-MS/MS).

    PubMed

    van de Merwe, Jason Paul; Hodge, Mary; Whittier, Joan Margaret; Lee, Shing Yip

    2009-03-01

    Investigation into persistent organic pollutants (POPs) in sea turtles is an important area of conservation research due to the harmful effects of these chemicals. However, the analysis of POPs in the green sea turtle (Chelonia mydas) has been limited by methods with relatively high limits of detection and high costs associated with multiple sample injections into complex arrangements of analytical equipment. The present study aimed to develop a method that could detect a large number of POPs in the blood, eggs and tissue of C. mydas at trace concentrations. A gas chromatography with tandem mass spectrometry (GC-MS/MS) method was developed that could report 125 POP compounds to a limit of detection of <35 pg g(-1) using a single sample injection. The recoveries of internal standards ranged from 30% to 96%, and the standard reference materials were reported to within 70% of the certified values. The coefficient of variation of ten replicates of pooled egg sample was <20% for all compounds, indicating low within-run variation. This GC-MS/MS method is an improvement of previous methods for analysing POPs in C. mydas in that more compounds can be reported at lower concentrations and the accuracy and precision of the method are sound. This is particularly important for C. mydas as they occupy a low trophic level and have lower concentrations of POPs. This method is also simple to set up, and there are minimal differences in sample preparation for the different tissue types.

  10. Detection of a rare BCR-ABL tyrosine kinase fusion protein in H929 multiple myeloma cells using immunoprecipitation (IP)-tandem mass spectrometry (MS/MS).

    PubMed

    Breitkopf, Susanne B; Yuan, Min; Pihan, German A; Asara, John M

    2012-10-01

    Hypothesis directed proteomics offers higher throughput over global analyses. We show that immunoprecipitation (IP)-tandem mass spectrometry (LC-MS/MS) in H929 multiple myeloma (MM) cancer cells led to the discovery of a rare and unexpected BCR-ABL fusion, informing a therapeutic intervention using imatinib (Gleevec). BCR-ABL is the driving mutation in chronic myeloid leukemia (CML) and is uncommon to other cancers. Three different IP-MS experiments central to cell signaling pathways were sufficient to discover a BCR-ABL fusion in H929 cells: phosphotyrosine (pY) peptide IP, p85 regulatory subunit of phosphoinositide-3-kinase (PI3K) IP, and the GRB2 adaptor IP. The pY peptides inform tyrosine kinase activity, p85 IP informs the activating adaptors and receptor tyrosine kinases (RTKs) involved in AKT activation and GRB2 IP identifies RTKs and adaptors leading to ERK activation. Integration of the bait-prey data from the three separate experiments identified the BCR-ABL protein complex, which was confirmed by biochemistry, cytogenetic methods, and DNA sequencing revealed the e14a2 fusion transcript. The tyrosine phosphatase SHP2 and the GAB2 adaptor protein, important for MAPK signaling, were common to all three IP-MS experiments. The comparative treatment of tyrosine kinase inhibitor (TKI) drugs revealed only imatinib, the standard of care in CML, was inhibitory to BCR-ABL leading to down-regulation of pERK and pS6K and inhibiting cell proliferation. These data suggest a model for directed proteomics from patient tumor samples for selecting the appropriate TKI drug(s) based on IP and LC-MS/MS. The data also suggest that MM patients, in addition to CML patients, may benefit from BCR-ABL diagnostic screening.

  11. Quantification of isoflavones in coffee by using solid phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

    PubMed

    Caprioli, Giovanni; Navarini, Luciano; Cortese, Manuela; Ricciutelli, Massimo; Torregiani, Elisabetta; Vittori, Sauro; Sagratini, Gianni

    2016-09-01

    A new method for extracting isoflavones from espresso coffee (EC) was coupled with high-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the first time to analyse five isoflavones, which included both a glycosilated form, genistin and the aglycons daidzein, genistein, formononetin and biochanin A. Isoflavones were extracted from coffee samples using methanol, stored in a freezer overnight to precipitate proteic or lipidic residues and purified on SPE C18 cartridges before high-performance liquid chromatography-MS/MS analysis. The recovery percentages obtained by spiking the matrix at concentrations of 10 and 100 µg l(-1) with a standard mixture of isoflavones were in the range of 70 to 104%. The limits of detection and limits of quantification were in the range of 0.015-0.3 µg l(-1) and 0.05-1 µg l(-1) , respectively. Once validated, the method was used to analyze the concentrations of isoflavones in six ECs and ten ground coffee samples. Only formononetin and biochanin A were found, and their respective concentrations ranged from 0.36 to 0.41 µg l(-1) and from 0.58 to 3.26 µg l(-1) in ECs and from 0.36 to 4.27 µg kg(-1) and from 0.71 to 3.95 µg kg(-1) in ground coffees. This method confirms the high specificity and selectivity of MS/MS systems for detecting bioactives in complex matrices such as coffee.Copyright © 2016 John Wiley & Sons, Ltd. PMID:27628757

  12. Bile Acid Metabolome after an Oral Lipid Tolerance Test by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

    PubMed Central

    Schmid, Andreas; Neumann, Hannah; Karrasch, Thomas; Liebisch, Gerhard; Schäffler, Andreas

    2016-01-01

    Context Besides their role in intestinal resorption of lipids, bile acids are regarded as endocrine and metabolic signaling molecules. The detailed profile of bile acid species in peripheral blood after an oral lipid tolerance test (OLTT) is unknown. Objective We quantified the regulation of 18 bile acids after OLTT in healthy individuals. Material and methods 100 volunteers were characterized by anthropometric and laboratory parameters and underwent OLTT. Venous blood was drawn in the fasted state (0 h) and at 2h, 4h, and 6 h after OLTT. Serum concentrations of 18 bile acids were measured by LC-MS/MS. Results All of the 6 taurine-conjugated bile acids (TUDCA, THDCA, TCA, TCDCA, TDCA, TLCA) and all of the 6 glycine-conjugated bile acids (GUDCA, GHDCA, GCA, GCDCA, GDCA, GLCA) rose significantly at 2h and remained elevated during OLTT. Of the primary bile acids, CA remained unchanged, whereas CDCA significantly decreased at 4h. Of the secondary bile acids, DCA, UDCA and HDCA were not altered, whereas LCA decreased. There was a significant positive correlation between the intestinal feed-back regulator of bile acid synthesis FGF-19 and bile acids. This correlation seems to depend on all of the six taurine-conjugated bile acids and on GCA, GDCA, and GCDCA. Females and users of hormonal contraception displayed higher levels of taurine-conjugated bile acids. Conclusions The novelty of the study is based on the identification of single bile acids during OLTT. LC-MS/MS-based quantification of bile acids in serum provides a reliable tool for future investigation of endocrine and metabolic effects of bile acids. PMID:26863103

  13. Optimization and Application of APCI Hydrogen-Deuterium Exchange Mass Spectrometry (HDX MS) for the Speciation of Nitrogen Compounds

    NASA Astrophysics Data System (ADS)

    Acter, Thamina; Cho, Yunju; Kim, Sungji; Ahmed, Arif; Kim, Byungjoo; Kim, Sunghwan

    2015-09-01

    A systematic study was performed to investigate the utility of atmospheric pressure chemical ionization hydrogen-deuterium exchange mass spectrometry (APCI HDX MS) to identify the structures of nitrogen-containing aromatic compounds. First, experiments were performed to determine the optimized experimental conditions, with dichloromethane and CH3OD found to be good cosolvents for APCI HDX. In addition, a positive correlation between the heated capillary temperature and the observed HDX signal was observed, and it was suggested that the HDX reaction occurred when molecules were contained in the solvent cluster. Second, 20 standard nitrogen-containing compounds were analyzed to investigate whether speciation could be determined based on the different types of ions produced from nitrogen-containing compounds with various functional groups. The number of exchanges occurring within the compounds correlated well with the number of active hydrogen atoms attached to nitrogen, and it was confirmed that APCI HDX MS could be used to determine speciation. The results obtained by APCI HDX MS were combined with the subsequent investigation of the double bond equivalence distribution and indicated that resins of shale oil extract contained mostly pyridine type nitrogen compounds. This study confirmed that APCI HDX MS can be added to previously reported chemical ionization, electrospray ionization, and atmospheric pressure photo ionization-based HDX methods, which can be used for structural elucidation by mass spectrometry.

  14. Optimization and Application of APCI Hydrogen-Deuterium Exchange Mass Spectrometry (HDX MS) for the Speciation of Nitrogen Compounds.

    PubMed

    Acter, Thamina; Cho, Yunju; Kim, Sungji; Ahmed, Arif; Kim, Byungjoo; Kim, Sunghwan

    2015-09-01

    A systematic study was performed to investigate the utility of atmospheric pressure chemical ionization hydrogen-deuterium exchange mass spectrometry (APCI HDX MS) to identify the structures of nitrogen-containing aromatic compounds. First, experiments were performed to determine the optimized experimental conditions, with dichloromethane and CH(3)OD found to be good cosolvents for APCI HDX. In addition, a positive correlation between the heated capillary temperature and the observed HDX signal was observed, and it was suggested that the HDX reaction occurred when molecules were contained in the solvent cluster. Second, 20 standard nitrogen-containing compounds were analyzed to investigate whether speciation could be determined based on the different types of ions produced from nitrogen-containing compounds with various functional groups. The number of exchanges occurring within the compounds correlated well with the number of active hydrogen atoms attached to nitrogen, and it was confirmed that APCI HDX MS could be used to determine speciation. The results obtained by APCI HDX MS were combined with the subsequent investigation of the double bond equivalence distribution and indicated that resins of shale oil extract contained mostly pyridine type nitrogen compounds. This study confirmed that APCI HDX MS can be added to previously reported chemical ionization, electrospray ionization, and atmospheric pressure photo ionization-based HDX methods, which can be used for structural elucidation by mass spectrometry.

  15. Quantification of Tricyclic Antidepressants in Serum Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    PubMed

    Crutchfield, Christopher A; Breaud, Autumn R; Clarke, William A

    2016-01-01

    Tricyclic antidepressants (TCA) are used to treat major depressive disorder and other psychological conditions. The efficacy of these drugs is tied to a narrow therapeutic window. Inappropriately high drug concentrations can result in serious side effects such as hypotension, tachycardia, or coma. As a result, concentrations of tricyclic antidepressants are routinely monitored to ensure compliance and to prevent adverse side effects by dose adjustments. We describe a method for the determination of concentrations of amitriptyline, desipramine, imipramine, and nortriptyline in human serum using high-performance liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization (HPLC-ESI-MS/MS). The method is rapid, requiring only 3.5 min per analysis. The method requires 100 μL of serum. Concentrations of each TCA were quantified by a calibration curve relating the peak area ratio of each TCA analyte to a deuterated internal standard (amitriptyline-D3, desipramine-D3, imipramine-D3, and nortriptyline-D3). The method was linear from ~70 ng/mL to ~1000 ng/mL for all TCAs, with imprecision ≤ 12%.

  16. Imidacloprid Extraction from Citrus Leaves and Analysis by Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS).

    PubMed

    Leiva, Jorge A; Nkedi-Kizza, Peter; Borejsza-Wysocki, Wlodzimierz S; Bauder, Victor S; Morgan, Kelly T

    2016-05-01

    A procedure was developed to extract Imidacloprid (IMD) from newly-flushed and fully-expanded citrus leaves. The extraction was conducted in a bullet blender, using a small sample mass (0.5 g of fresh tissue), stainless-steel beads (24 g), and methanol as extractant (10 mL). The extracts did not require further clean-up before analysis by HPLC-MS/MS. The method was validated with control samples from IMD-untreated Hamlin orange trees. The method limit of detection and limit of quantitation were 0.04 and 0.12 μg g(-1), respectively. IMD recoveries from fortified leaf tissue were between 92 % and 102 %, with relative standard deviations of <8 %. The method was further evaluated by extracting leaves from Hamlin orange trees treated with IMD. The treated trees showed maximum concentrations of 10.8 and 21.8 µg g(-1), observed at 20 days after applying two soil-drenching rates (0.51 and 1.02 kg IMD ha(-1)), respectively. This extraction technique will generate useful data on IMD plant uptake, foliar concentration, and correlations with Asian citrus psyllid (ACP) mortality or control. The method could be used to generate baseline data to improve IMD soil-drenching applications as the main management practice to control the ACP. PMID:26988226

  17. Method optimization and quality assurance in speciation analysis using high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Larsen, Erik H.

    1998-02-01

    Achievement of optimum selectivity, sensitivity and robustness in speciation analysis using high performance liquid chromatography (HPLC) with inductively coupled mass spectrometry (ICP-MS) detection requires that each instrumental component is selected and optimized with a view to the ideal operating characteristics of the entire hyphenated system. An isocratic HPLC system, which employs an aqueous mobile phase with organic buffer constituents, is well suited for introduction into the ICP-MS because of the stability of the detector response and high degree of analyte sensitivity attained. Anion and cation exchange HPLC systems, which meet these requirements, were used for the seperation of selenium and arsenic species in crude extracts of biological samples. Furthermore, the signal-to-noise ratios obtained for these incompletely ionized elements in the argon ICP were further enhanced by a factor of four by continously introducing carbon as methanol via the mobile phase into the ICP. Sources of error in the HPLC system (column overload), in the sample introduction system (memory by organic solvents) and in the ICP-MS (spectroscopic interferences) and their prevention are also discussed. The optimized anion and cation exchange HPLC-ICP-MS systems were used for arsenic speciation in contaminated ground water and in an in-house shrimp reference sample. For the purpose of verification, HPLC coupled with tandem mass spectrometry with electrospray ionization was additionally used for arsenic speciation in the shrimp sample. With this analytical technique the HPLC retention time in combination with mass analysis of the molecular ions and their collision-induced fragments provide almost conclusive evidence of the identity of the analyte species. The speciation methods are validated by establishing a mass balance of the analytes in each fraction of the extraction procedure, by recovery of spikes and by employing and comparing independent techniques. The urgent need for

  18. EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)

    EPA Science Inventory

    Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water.

  19. Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

  20. High rates of non-adherence to antihypertensive treatment revealed by high-performance liquid chromatography-tandem mass spectrometry (HP LC-MS/MS) urine analysis

    PubMed Central

    Tomaszewski, Maciej; White, Christobelle; Patel, Prashanth; Masca, Nicholas; Damani, Ravi; Hepworth, Joanne; Samani, Nilesh J; Gupta, Pankaj; Madira, Webster; Stanley, Adrian; Williams, Bryan

    2014-01-01

    Objectives Non-adherence to therapy is an important cause of suboptimal blood pressure control but few practical tools exist to accurately and routinely detect it. We used a simple urine-based assay to evaluate the prevalence of antihypertensive treatment non-adherence and its impact on blood pressure in a specialist hypertension centre. Methods 208 hypertensive patients (125 new referrals, 66 follow-up patients with inadequate blood pressure control and 17 renal denervation referrals) underwent assessment of antihypertensive drug intake using high-performance liquid chromatography-tandem mass spectrometry (HP LC-MS/MS) urine analysis at the time of clinical appointment. A total of 40 most commonly prescribed antihypertensive medications (or their metabolites) were screened for in spot urine samples. Results Overall, 25% of patients were totally or partially non-adherent to antihypertensive treatment (total non-adherence 10.1%, partial non-adherence 14.9%). The highest prevalence of partial and total non-adherence was among follow-up patients with inadequate blood pressure control (28.8%) and those referred for consideration of renal denervation (23.5%), respectively. There was a linear relationship between blood pressure and the numerical difference in detected/prescribed antihypertensive medications—every unit increase in this difference was associated with 3.0 (1.1) mm Hg, 3.1 (0.7) mm Hg and 1.9 (0.7) mm Hg increase in adjusted clinic systolic blood pressure, clinic diastolic blood pressure (DBP) and 24 h mean daytime DBP (p=0.0051, p=8.62×10−6, p=0.0057), respectively. Conclusions Non-adherence to blood pressure lowering therapy is common, particularly in patients with suboptimal blood pressure control and those referred for renal denervation. HP LC-MS/MS urine analysis could be used to exclude non-adherence and better stratify further investigations and intervention. PMID:24694797

  1. Analytical Determination of Vitamin B12 Content in Infant and Toddler Milk Formulas by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

    PubMed Central

    Lee, Jung-Hoon; Shin, Jin-Ho; Park, Jung-Min; Kim, Ha-Jung; Ahn, Jang-Hyuk; Kwak, Byung-Man; Kim, Jin-Man

    2015-01-01

    The development of a sample preparation method and optimization of the analytical instrumentation conditions were performed for the determination of the vitamin B12 content in emulsified baby foods sold on the Korea market. After removal of the milk protein and fats by chloroform extraction and centrifugation, the vitamin B12 was water extracted from the sample. Following filtration of the solution through a nylon filter, the water-soluble extract was purified by solid-phase extraction using a Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The solution eluted from the cartridge was dried under a stream of nitrogen gas and reconstituted with 1 mL of water. The sample solution was injected into an LC-MS/MS system after optimizing the mobile phase for vitamin B12 detection. The calibration curve showed good linearity with the coefficient of correlation (r2) value of 0.9999. The limit of detection was 0.03 µg/L and the limit of quantitation was 0.1 µg/L. The method of detection limit was 0.02 µg/kg. The vitamin B12 recovery from a spiking test was 99.62% for infant formula and 99.46% for cereal-based baby food. The sample preparation method developed in this study would be appropriate for the rapid determination of the vitamin B12 content in infant formula and baby foods with emulsified milk characteristics. The ability to obtain stable results more quickly and efficiently would also allow governments to exercise a more extensive quality control inspection and monitoring of products expected to contain vitamin B12. This method could be implemented in laboratories that require time and labor saving. PMID:26877636

  2. Selective derivatization of nucleotide diphosphate (NDP)-4-keto sugars for electrospray ionization-mass spectrometry (ESI-MS).

    PubMed

    Kim, Yun-Gon; Park, Hyung-Yeon; Yoo, Dongwon; Sung, Changmin; Song, Eunjung; Lee, Jae-Hun; Choi, Yun-Hui; Kim, Yong-Hyun; Lee, Chang-Soo; Park, Kyungmoon; Kim, Byung-Gee; Yang, Yung-Hun

    2012-04-15

    Nucleotide diphosphate (NDP) sugars are widely present in antibiotics and glycoconjugates, such as protein- and lipid-linked oligosaccharides, where they act as substrates for glycosyltransferase in eukaryotes and prokaryotes. Among NDP sugars, NDP-4-keto sugars are key intermediates in the synthesis of structurally diverse NDP sugars with different functional groups. However, the structural identification of the NDP-4-keto sugars via mass spectrometry (electrospray ionization-mass spectrometry (ESI-MS)) continues to be a challenge because of the carbonyl group in these sugars interferes with ionization process. In this study, we evaluated various hydroxylamine compounds for the derivatization of NDP-4-keto sugars, so that the detection of the sugars by ESI-MS is more efficient. As a result, O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine was found to be the most effective tagging molecule for the detection of NDP-4-keto sugars without being interfered by original MS. This method can be used for identifying NDP-4-keto sugars such as thymidine diphosphate (TDP)-, adenosine diphosphate (ADP)-, uridine diphosphate (UDP)-, and cytosine diphosphate (CDP)-4-keto sugars as well as new NDP-4-keto-dehydratases.

  3. Combining Ion Mobility Spectrometry with Hydrogen-Deuterium Exchange and Top-Down MS for Peptide Ion Structure Analysis

    NASA Astrophysics Data System (ADS)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Maleki, Hossein; Arndt, James R.; Donohoe, Gregory C.; Valentine, Stephen J.

    2014-12-01

    The gas-phase conformations of electrosprayed ions of the model peptide KKDDDDIIKIIK have been examined by ion mobility spectrometry (IMS) and hydrogen deuterium exchange (HDX)-tandem mass spectrometry (MS/MS) techniques. [M+4H]4+ ions exhibit two conformers with collision cross sections of 418 Å2 and 471 Å2. [M+3H]3+ ions exhibit a predominant conformer with a collision cross section of 340 Å2 as well as an unresolved conformer (shoulder) with a collision cross section of ~367 Å2. Maximum HDX levels for the more compact [M+4H]4+ ions and the compact and partially-folded [M+3H]3+ ions are ~12.9, ~15.5, and ~14.9, respectively. Ion structures obtained from molecular dynamics simulations (MDS) suggest that this ordering of HDX level results from increased charge-site/exchange-site density for the more compact ions of lower charge. Additionally, a new model that includes two distance calculations (charge site to carbonyl group and carbonyl group to exchange site) for the computer-generated structures is shown to better correlate to the experimentally determined per-residue deuterium uptake. Future comparisons of IMS-HDX-MS data with structures obtained from MDS are discussed with respect to novel experiments that will reveal the HDX rates of individual residues.

  4. High temperature gas chromatography-time-of-flight-mass spectrometry (HTGC-ToF-MS) for high-boiling compounds.

    PubMed

    Sutton, P A; Rowland, S J

    2012-06-22

    High temperature gas chromatography (HTGC) is a routine technique for the analysis of high boiling compounds which are eluted from the column with oven cycling up to > 400 °C. In contrast, the coupling of HTGC with mass spectrometry (HTGC-MS) has received relatively little attention. This may be due to the availability of GC columns, mass spectrometers and accessories that are able to withstand constant high temperature cycling. We have assembled a HTGC-time of flight-MS (HTGC-ToF-MS) system from readily available products that is capable of rapid (<25 min) analysis of ∼C₁₀₋₁₀₀ hydrocarbon boiling equivalents and full mass spectral data recording up to m/z 1850. Here we report initial results from the analysis of diverse substrates including:long-chain (> C₆₀) n-alkanes, n-acid methyl esters up to C₆₄, triacylglycerides (TAGs) with molecular and fragment ions in a single analysis, intact wax esters from C₄₀₋₆₄, C₈₀ glycerol alkyl glycerol tetraethers (GDGTs), and C₃₃₋₄₄ metallated porphyrins. Mass spectrometry at 430 °C was achievable on a routine basis without significant thermal degradation of analytes. The method is applicable to analysis of a wide range of industrial, environmental, biological, geochemical and other samples where high molecular weight analytes are of interest.

  5. Simultaneous separation of 17 inorganic and organic arsenic compounds in marine biota by means of high-performance liquid chromatography/inductively coupled plasma mass spectrometry.

    PubMed

    Kohlmeyer, Ute; Kuballa, Jürgen; Jantzen, Eckard

    2002-01-01

    A method using high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS) has been developed to determine inorganic arsenic (arsenite, arsenate) along with organic arsenic compounds (monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium ion and several arsenosugars) in fish, mussel, oyster and marine algae samples. The species were extracted by means of a methanol/water mixture and a dispersion unit in 2 min, with extraction efficiencies ranging from 83 to 107% in the different organisms. Up to 17 different species were determined within 15 min on an anion-exchange column, using a nitric acid gradient and an ion-pairing reagent. As all species are shown in one chromatogram, a clear overview of arsenic distribution patterns in different marine organisms is given. Arsenobetaine is the major compound in marine animals whereas arsenosugars and arsenate are dominant in marine algae. The method was validated with CRM DORM-2 (dogfish muscle). Concentrations were within the certified limits and low detection limits of 8 ng g(-1) (arsenite) to 50 ng g(-1) (arsenate) were obtained. PMID:11968129

  6. Deconstruction of activity-dependent covalent modification of heme in human neutrophil myeloperoxidase by multistage mass spectrometry (MS(4)).

    PubMed

    Geoghegan, Kieran F; Varghese, Alison H; Feng, Xidong; Bessire, Andrew J; Conboy, James J; Ruggeri, Roger B; Ahn, Kay; Spath, Samantha N; Filippov, Sergey V; Conrad, Steven J; Carpino, Philip A; Guimarães, Cristiano R W; Vajdos, Felix F

    2012-03-13

    Myeloperoxidase (MPO) is known to be inactivated and covalently modified by treatment with hydrogen peroxide and agents similar to 3-(2-ethoxypropyl)-2-thioxo-2,3-dihydro-1H-purin-6(9H)-one (1), a 254.08 Da derivative of 2-thioxanthine. Peptide mapping by liquid chromatography and mass spectrometry detected modification by 1 in a labile peptide-heme-peptide fragment of the enzyme, accompanied by a mass increase of 252.08 Da. The loss of two hydrogen atoms was consistent with mechanism-based oxidative coupling. Multistage mass spectrometry (MS(4)) of the modified fragment in an ion trap/Orbitrap spectrometer demonstrated that 1 was coupled directly to heme. Use of a 10 amu window delivered the full isotopic envelope of each precursor ion to collision-induced dissociation, preserving definitive isotopic profiles for iron-containing fragments through successive steps of multistage mass spectrometry. Iron isotope signatures and accurate mass measurements supported the structural assignments. Crystallographic analysis confirmed linkage between the methyl substituent of the heme pyrrole D ring and the sulfur atom of 1. The final orientation of 1 perpendicular to the plane of the heme ring suggested a mechanism consisting of two consecutive one-electron oxidations of 1 by MPO. Multistage mass spectrometry using stage-specific collision energies permits stepwise deconstruction of modifications of heme enzymes containing covalent links between the heme group and the polypeptide chain.

  7. Increasing Confidence of LC-MS Identifications by Utilizing Ion Mobility Spectrometry

    SciTech Connect

    Crowell, Kevin L.; Baker, Erin Shammel; Payne, Samuel H.; Ibrahim, Yehia M.; Monroe, Matthew E.; Slysz, Gordon W.; Lamarche, Brian L.; Petyuk, Vladislav A.; Piehowski, Paul D.; Danielson, William F.; Anderson, Gordon A.; Smith, Richard D.

    2013-09-05

    Ion mobility spectrometry in conjunction with liquid chromatography separations and mass spectrometry offers a range of new possibilities for analyzing complex biological samples. To fully utilize the information obtained from these three measurement dimensions, informatics tools based on the accurate mass and time tag methodology were modified to incorporate ion mobility spectrometry drift times for peptides observed in human serum. A reference human serum database was created using 12,139 peptides, tracking the monoisotopic mass, liquid chromatography normalized elution time, and ion mobility spectrometry drift time(s) for each peptide. We demonstrate that the use of three dimensions for peak matching during the peptide identification process resulted in increased numbers of identifications and lower false discovery rates relative to the use of only the mass and normalized elution time dimensions.

  8. Simultaneous determination of vitamins A and D3 in dairy products by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

    NASA Astrophysics Data System (ADS)

    Barakat, I. S. A.; Hammouri, M. K.; Habib, I.

    2015-10-01

    A potential method for simultaneous determination of vitamin A and vitamin D3 (25- hydroxyvitamin D3) in fresh milk samples is addressed. The method is based on combination of high performance liquid chromatography and mass spectrometry during the course of analysis. The method applied for determination of vitamins A and D3 on eighteen (18) different fresh milk samples using liquid chromatography along with tandem -mass spectrometry. The work describes the suitability of the proposed method for the simultaneous determination of both vitamins using LC-MS/MS as a specific and quantitative technique. The vitamins of milk were separated by C18 Thermo gold column(100mm × 4.6mm × 5 μm) with a flow rate of 1ml/min (using an isocratic mobile phase). The method was validated using duplicate analyses, relative recovery experiment, and comparative analysis with control samples. Liquid- liquid extraction was employed as a pre-concentration step with n-hexane - dichloromethane mixture (90%:10%) as an extraction solvent. The molecular ions (m/z) appeared near 286 and 385nm and for the base peaks were appeared near 255 and 355nm for vitamins A and D3. Good correlation coefficients were obtained, 0.9999 for vitamin D3 and 0.9994 for vitamin A. The limit of detection and the limit of quantification were found to be 0.09ng/ml and 0.54ng/ml for vitamin D3 and 0.32ng/ml and 1.8ng/ml and for vitamin A. The proposed method showed excellent recoveries, about 98% for both vitamins A and D3.

  9. Utilization of Negative Ion ESI-MS and Tandem Mass Spectrometry to Detect and Confirm the NADH-Boric Acid Complex

    ERIC Educational Resources Information Center

    Kim, Danny H.; Eckhert, Curtis D.; Faull, Kym F.

    2011-01-01

    Mass spectrometry (MS) is a powerful analytical technique that is now widely used in the chemical, physical, engineering, and life sciences, with rapidly growing applications in many areas including clinical, forensic, pharmaceutical, and environmental fields. The increase in use of MS in both academic and industrial settings for research and…

  10. 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. PMID:24321357

  11. Potential for using isotopically altered metalloproteins in species-specific isotope dilution analysis of proteins by HPLC coupled to inductively coupled plasma mass spectrometry.

    PubMed

    Harrington, Chris F; Vidler, Daniel S; Watts, Michael J; Hall, John F

    2005-07-01

    The production and evaluation of an isotopically enriched metalloprotein standard for use as a calibrant in species-specific isotope dilution analysis by HPLC coupled to inductively coupled plasma mass spectrometry is described. Using a model system involving the copper-containing protein rusticyanin (Rc) from the bacterium Acido-thiobacillus ferrooxidans, it was possible to demonstrate the analytical conditions that could be used for the measurement of metalloproteins by on-line IDMS analysis. Rc was chosen because it is a well-characterized protein with an established amino acid sequence and can be produced in suitable quantities using a bacterial recombinant system. Three different forms of the protein were studied by organic and inorganic mass spectrometry: the native form of the protein containing a natural isotopic profile for copper, an isotopically enriched species containing virtually all of its copper as the 65Cu isotope, and the nonmetalated apo form. Incorporation of the copper isotopes into the apo form of the protein was determined using a UV-vis spectrophotometric assay and shown to be complete for each of the copper-containing species. The experimental conditions required to maintain the conformational form of the protein with a nonexchangeable copper center were established using +ve electrospray mass spectrometry. A pH 7.0 buffer was found to afford the most appropriate conditions, and this was then used with HPLC-ICP-MS to verify the stability of the copper center by analysis of mixtures of different isotopic solutions. No exchange of the enriched copper isotope from Rc with an added naturally abundant inorganic copper cation was observed under a neutral pH environment, indicating that species-specific ID-MS analysis of metalloproteins is possible.

  12. 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.

  13. Development of a multi-class steroid hormone screening method using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Boggs, Ashley S P; Bowden, John A; Galligan, Thomas M; Guillette, Louis J; Kucklick, John R

    2016-06-01

    Monitoring complex endocrine pathways is often limited by indirect measurement or measurement of a single hormone class per analysis. There is a burgeoning need to develop specific direct-detection methods capable of providing simultaneous measurement of biologically relevant concentrations of multiple classes of hormones (estrogens, androgens, progestogens, and corticosteroids). The objectives of this study were to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for multi-class steroid hormone detection using biologically relevant concentrations, then test limits of detection (LOD) in a high-background matrix by spiking charcoal-stripped fetal bovine serum (FBS) extract. Accuracy was tested with National Institute of Standards and Technology Standard Reference Materials (SRMs) with certified concentrations of cortisol, testosterone, and progesterone. 11-Deoxycorticosterone, 11-deoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, adrenosterone, androstenedione, cortisol, corticosterone, dehydroepiandrosterone, dihydrotestosterone, estradiol, estriol, estrone, equilin, pregnenolone, progesterone, and testosterone were also measured using isotopic dilution. Dansyl chloride (DC) derivatization was investigated maintaining the same method to improve and expedite estrogen analysis. Biologically relevant LODs were determined for 15 hormones. DC derivatization improved estrogen response two- to eight-fold, and improved chromatographic separation. All measurements had an accuracy ≤14 % difference from certified values (not accounting for uncertainty) and relative standard deviation ≤14 %. This method chromatographically separated and quantified biologically relevant concentrations of four hormone classes using highly specific fragmentation patterns and measured certified values of hormones that were previously split into three separate chromatographic methods. PMID:27039201

  14. The Development of Electrostatic Precipitation-Electrospray Ionization Mass Spectrometry (EP-ESI-MS) for Atmospheric Aerosol Analysis

    NASA Astrophysics Data System (ADS)

    He, S.; Hogan, C. J., Jr.; Naqwi, A.; Gross, D. S.; Li, L.; Duan, H.; Jiang, L.; Flowers, J.; Grubb, E.; Au, L.

    2015-12-01

    Chemical composition analysis of atmospheric aerosols is of considerable interest and has been facilitated by mass spectrometry. Electrospray ionization (ESI) is a suitable mode of ion generation of many organic species comprising aerosol particles, as it leads to minimal analyte fragmentation. However, particles exist in the atmosphere at mass concentrations of the order 10 μg/m3 or less in many environments and are highly heterogeneous; low concentrations and chemical complexity have limited ESI application in aerosol analysis. In this presentation, the development of an approach to apply ESI to molecules within submicrometer and nanometer scale aerosol particles is discussed. The technique, which we term electrostatic precipitation-ESI-MS (EP-ESI-MS), utilizes unipolar ionization to charge particles, electrostatic precipitation to collect particles on the tip of a tungsten rod, and subsequently, by flowing liquid over the rod, ESI and mass analysis of dissolved species originating from the collected particles. EP-ESI-MS is shown to enable analysis of nanogram quantities of collected inorganic and organic components. Furthermore, it is coupled with a tandem mass spectrometry and challenged with oxidation products of α-pinene to investigate its capability of enabling structure analysis of complex organic compounds in aerosol particles. With EP-ESI-MS, the identification of chemical components in aerosol particles is realized and the integrated mass spectrometric signals are found to be a monotonic function of the analyte mass concentration in the aerosol phase. Additionally, it is shown to have a dynamic range of 5 orders of magnitude in mass, making it suitable for molecular analysis of aerosol particles in laboratory settings, as well as analysis of atmospheric aerosols in ambient air.

  15. Cysteine shotgun–mass spectrometry (CS-MS) reveals dynamic sequence of protein structure changes within mutant and stressed cells

    PubMed Central

    Krieger, Christine C.; An, Xiuli; Tang, Hsin-Yao; Mohandas, Narla; Speicher, David W.; Discher, Dennis E.

    2011-01-01

    Questions of if and when protein structures change within cells pervade biology and include questions of how the cytoskeleton sustains stresses on cells—particularly in mutant versus normal cells. Cysteine shotgun labeling with fluorophores is analyzed here with mass spectrometry of the spectrin–actin membrane skeleton in sheared red blood cell ghosts from normal and diseased mice. Sheared samples are compared to static samples at 37 °C in terms of cell membrane intensity in fluorescence microscopy, separated protein fluorescence, and tryptic peptide modification in liquid chromatography–tandem mass spectrometry (LC-MS/MS). Spectrin labeling proves to be the most sensitive to shear, whereas binding partners ankyrin and actin exhibit shear thresholds in labeling and both the ankyrin-binding membrane protein band 3 and the spectrin–actin stabilizer 4.1R show minimal differential labeling. Cells from 4.1R-null mice differ significantly from normal in the shear-dependent labeling of spectrin, ankyrin, and band 3: Decreased labeling of spectrin reveals less stress on the mutant network as spectrin dissociates from actin. Mapping the stress-dependent labeling kinetics of α- and β-spectrin by LC-MS/MS identifies Cys in these antiparallel chains that are either force-enhanced or force-independent in labeling, with structural analyses indicating the force-enhanced sites are sequestered either in spectrin’s triple-helical domains or in interactions with actin or ankyrin. Shear-sensitive sites identified comprehensively here in both spectrin and ankyrin appear consistent with stress relief through forced unfolding followed by cytoskeletal disruption. PMID:21527722

  16. Quantitative Analysis of Staphylococcal Enterotoxins A and B in Food Matrices Using Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS)

    PubMed Central

    Zuberovic Muratovic, Aida; Hagström, Thomas; Rosén, Johan; Granelli, Kristina; Hellenäs, Karl-Erik

    2015-01-01

    A method that uses mass spectrometry (MS) for identification and quantification of protein toxins, staphylococcal enterotoxins A and B (SEA and SEB), in milk and shrimp is described. The analysis was performed using a tryptic peptide, from each of the toxins, as the target analyte together with the corresponding 13C-labeled synthetic internal standard peptide. The performance of the method was evaluated by analyzing spiked samples in the quantification range 2.5–30 ng/g (R2 = 0.92–0.99). The limit of quantification (LOQ) in milk and the limit of detection (LOD) in shrimp was 2.5 ng/g, for both SEA and SEB toxins. The in-house reproducibility (RSD) was 8%–30% and 5%–41% at different concentrations for milk and shrimp, respectively. The method was compared to the ELISA method, used at the EU-RL (France), for milk samples spiked with SEA at low levels, in the quantification range of 2.5 to 5 ng/g. The comparison showed good coherence for the two methods: 2.9 (MS)/1.8 (ELISA) and 3.6 (MS)/3.8 (ELISA) ng/g. The major advantage of the developed method is that it allows direct confirmation of the molecular identity and quantitative analysis of SEA and SEB at low nanogram levels using a label and antibody free approach. Therefore, this method is an important step in the development of alternatives to the immune-assay tests currently used for staphylococcal enterotoxin analysis. PMID:26378579

  17. Accurate Quantification of Selenoprotein P (SEPP1) in Plasma Using Isotopically Enriched Seleno-peptides and Species-Specific Isotope Dilution with HPLC Coupled to ICP-MS/MS.

    PubMed

    Deitrich, Christian L; Cuello-Nuñez, Susana; Kmiotek, Diana; Torma, Frank Attila; Del Castillo Busto, Maria Estela; Fisicaro, Paola; Goenaga-Infante, Heidi

    2016-06-21

    A novel strategy for the absolute quantification of selenium (Se) included in selenoprotein P (SEPP1), an important biomarker for human nutrition and disease, including diabetes and cancer, is presented here for the first time. It is based on the use of species-specific double isotope dilution mass spectrometry (SSIDA) in combination with HPLC-ICP-MS/MS for the determination of protein bound Se down to the peptide level in a complex plasma matrix with a total content of Se of 105.5 μg kg(-1). The method enabled the selective Se speciation analysis of human plasma samples without the need of extensive cleanup or preconcentration steps as required for traditional protein mass spectrometric approaches. To assess the method accuracy, two plasma reference materials, namely, BCR-637 and SRM1950, for which literature data and a reference value for SEPP1 have been reported, were analyzed using complementary hyphenated methods and the species-specific approach developed in this work. The Se mass fractions obtained via the isotopic ratios (78)Se/(76)Se and (82)Se/(76)Se for each of the Se-peptides, namely, ENLPSLCSUQGLR (ENL) and AEENITESCQUR (AEE) (where U is SeCys), were found to agree within 2.4%. A relative expanded combined uncertainty (k = 2) of 5.4% was achieved for a Se (as SEPP1) mass fraction of approximately 60 μg kg(-1). This work represents a systematic approach to the accurate quantitation of plasma SEPP1 at clinical levels using SSIDA quantification. Such methodology will be invaluable for the certification of reference materials and the provision of reference values to clinical measurements and clinical trials. PMID:27108743

  18. Mass-spectrometry analysis of histone post-translational modifications in pathology tissue using the PAT-H-MS approach.

    PubMed

    Noberini, Roberta; Pruneri, Giancarlo; Minucci, Saverio; Bonaldi, Tiziana

    2016-06-01

    Aberrant histone post-translational modifications (hPTMs) have been implicated with various pathologies, including cancer, and may represent useful epigenetic biomarkers. The data described here provide a mass spectrometry-based quantitative analysis of hPTMs from formalin-fixed paraffin-embedded (FFPE) tissues, from which histones were extracted through the recently developed PAT-H-MS method. First, we analyzed FFPE samples from mouse spleen and liver or human breast cancer up to six years old, together with their corresponding fresh frozen tissue. We then combined the PAT-H-MS approach with a histone-focused version of the super-SILAC strategy-using a mix of histones from four breast cancer cell lines as a spike-in standard- to accurately quantify hPTMs from breast cancer specimens belonging to different subtypes. The data, which are associated with a recent publication (Pathology tissue-quantitative mass spectrometry analysis to profile histone post-translational modification patterns in patient samples (Noberini, 2015) [1]), are deposited at the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD002669. PMID:27408908

  19. Provenance determination of oriental porcelain using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).

    PubMed

    Bartle, Emma K; Watling, R John

    2007-03-01

    The sale of fraudulent oriental ceramics constitutes a large proportion of the illegal artifact and antique trade and threatens to undermine the legitimate international market. The sophistication and skill of forgers has reached a level where, using traditional appraisal by eye and hand, even the most experienced specialist is often unable to distinguish between a genuine and fraudulent piece. In addition, current provenancing techniques such as energy-dispersive X-ray fluorescence (EDXRF) spectrometry and thermoluminescence (TL) dating can result in significant damage to the artifact itself. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a relatively nondestructive analytical technique, has been used for the provenance determination of materials based on geographical origin. The technique requires the production of a laser crater, c. 100 microm in diameter, which is essentially invisible to the naked eye. Debris from this crater is analyzed using ICP-MS, with the results forming the basis of the provenance establishment protocol. Chinese, Japanese, and English porcelain shards have been analyzed using this protocol and generic isotopic distribution patterns have been produced that enable the provenance establishment of porcelain artifacts to their country of production. Minor variations between elemental fingerprints of artifacts produced in the same country also indicate that it may be possible to further provenance oriental ceramics to a specific production region or kiln site.

  20. Comparative proteomic analysis of normal and tumor stromal cells by tissue on chip based mass spectrometry (toc-MS)

    PubMed Central

    2010-01-01

    In carcinoma tissues, genetic and metabolic changes not only occur at the tumor cell level, but also in the surrounding stroma. This carcinoma-reactive stromal tissue is heterogeneous and consists e.g. of non-epithelial cells such as fibroblasts or fibrocytes, inflammatory cells and vasculature-related cells, which promote carcinoma growth and progression of carcinomas. Nevertheless, there is just little knowledge about the proteomic changes from normal connective tissue to tumor stroma. In the present study, we acquired and analysed specific protein patterns of small stromal sections surrounding head and neck cell complexes in comparison to normal subepithelial connective tissue. To gain defined stromal areas we used laser-based tissue microdissection. Because these stromal areas are limited in size we established the highly sensitive 'tissue on chip based mass spectrometry' (toc-MS). Therefore, the dissected areas were directly transferred to chromatographic arrays and the proteomic profiles were subsequently analysed with mass spectrometry. At least 100 cells were needed for an adequate spectrum. The locating of differentially expressed proteins enables a precise separation of normal and tumor stroma. The newly described toc-MS technology allows an initial insight into proteomic differences between small numbers of exactly defined cells from normal and tumor stroma. PMID:20205871

  1. LC-MS-MS aboard ship: tandem mass spectrometry in the search for phycotoxins and novel toxigenic plankton from the North Sea.

    PubMed

    Krock, Bernd; Tillmann, Urban; John, Uwe; Cembella, Allan

    2008-11-01

    Phycotoxins produced by various species of toxigenic microalgae occurring in the plankton are a global threat to the security of seafood resources and the health of humans and coastal marine ecosystems. This has necessitated the development and application of advanced methods in liquid chromatography coupled to mass spectrometry (LC-MS) for monitoring of these compounds, particularly in plankton and shellfish. Most such chemical analyses are conducted in land-based laboratories on stored samples, and thus much information on the near real-time biogeographical distribution and dynamics of phycotoxins in the plankton is unavailable. To resolve this problem, we conducted ship-board analysis of a broad spectrum of phycotoxins collected directly from the water column on an oceanographic cruise along the North Sea coast of Scotland, Norway, and Denmark. We equipped the ship with a triple-quadrupole linear ion-trap hybrid LC-MS-MS system for detection and quantitative analysis of toxins, such as domoic acid, gymnodimine, spirolides, dinophysistoxins, okadaic acid, pectenotoxins, yessotoxins, and azaspiracids (AZAs). We focused particular attention on the detection of AZAs, a group of potent nitrogenous polyether toxins, because the culprit species associated with the occurrence of these toxins in shellfish has been controversial. Marine toxins were analyzed directly from size-fractionated plankton net tows (20 microm mesh size) and Niskin bottle samples from discrete depths, after rapid methanolic extraction but without any further clean-up. Almost all expected phycotoxins were detected in North Sea plankton samples, with domoic acid and 20-methylspirolide G being most abundant. Although AZA was the least abundant of these toxins, the high sensitivity of the LC-MS-MS enabled detailed quantification, indicating that the highest amounts of AZA-1 were present in the southern Skagerrak in the 3-20 microm size-fraction. The direct on-board toxin measurements enabled isolation

  2. Hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) determination of cocaine and its metabolites benzoylecgonine, ecgonine methyl ester, and cocaethylene in hair samples.

    PubMed

    Quintela, Oscar; Lendoiro, Elena; Cruz, Angelines; de Castro, Ana; Quevedo, Alfredo; Jurado, Carmen; López-Rivadulla, Manuel

    2010-03-01

    This study reports the development and validation of a method using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for the analysis of cocaine and its metabolites benzoylecgonine (BE), ecgonine methyl ester (EME), and cocaethylene (CE) in hair samples. Decontamination was performed as follows: Firstly, the aliquot of hair was briefly rinsed with 2 mL dichloromethane, then was washed three times with 10 mL 0.01 M phosphate buffer, pH 6, for 15 min, followed by 2 mL 2-propanol for less than 2 min, and, finally, a last rinse with 2 mL dichloromethane was again done. Cocaine compounds were extracted from 10 mg of hair by incubation with 2 mL 0.1 M HCl at 50 °C for 12 h and purified by solid phase extraction with Oasis MCX cartridges. Analysis was performed by LC-MS/MS using an Atlantis HILIC silica chromatographic column. The method was fully validated. Linearity was established over the concentration range 0.020-10.0 ng/mg for cocaine (COC), 0.010-10.0 ng/mg for BE and CE, and 0.005-2.0 ng/mg for EME, and the correlation coefficients were all >0.99. Extraction efficiency was >70% for all analytes. Limits of detection were 0.0005 ng/mg for CE and 0.001 ng/mg for the other analytes (COC, BE, and EME). Lower limits of quantification were the lowest points of the calibration curves with acceptable accuracy and precision (coefficient of variation ≤20%). Intra- and inter-day imprecision ranged between 1.5% and 9.5% and 0.7% and 12.6%, respectively. Intra- and inter-day inaccuracy ranged from 0.5% to 12.3% and from 0.7% to 7.1%, respectively. With regard to matrix effects, suppression was <27.5% in all cases. The method was applied to the analysis of several samples derived from forensic cases. PMID:20052577

  3. Gas chromatography coupled to atmospheric pressure ionization mass spectrometry (GC-API-MS): review.

    PubMed

    Li, Du-Xin; Gan, Lin; Bronja, Amela; Schmitz, Oliver J

    2015-09-01

    Although the coupling of GC/MS with atmospheric pressure ionization (API) has been reported in 1970s, the interest in coupling GC with atmospheric pressure ion source was expanded in the last decade. The demand of a "soft" ion source for preserving highly diagnostic molecular ion is desirable, as compared to the "hard" ionization technique such as electron ionization (EI) in traditional GC/MS, which fragments the molecule in an extensive way. These API sources include atmospheric pressure chemical ionization (APCI), atmospheric pressure photoionization (APPI), atmospheric pressure laser ionization (APLI), electrospray ionization (ESI) and low temperature plasma (LTP). This review discusses the advantages and drawbacks of this analytical platform. After an introduction in atmospheric pressure ionization the review gives an overview about the history and explains the mechanisms of various atmospheric pressure ionization techniques used in combination with GC such as APCI, APPI, APLI, ESI and LTP. Also new developments made in ion source geometry, ion source miniaturization and multipurpose ion source constructions are discussed and a comparison between GC-FID, GC-EI-MS and GC-API-MS shows the advantages and drawbacks of these techniques. The review ends with an overview of applications realized with GC-API-MS.

  4. Ion Mobility Mass Spectrometry for Ion Recovery and Clean-Up of MS and MS/MS Spectra Obtained from Low Abundance Viral Samples

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Crispin, Max; Bonomelli, Camille; Scrivens, Jim H.

    2015-07-01

    Many samples of complex mixtures of N-glycans released from small amounts of material, such as glycoproteins from viruses, present problems for mass spectrometric analysis because of the presence of contaminating material that is difficult to remove by conventional methods without involving sample loss. This study describes the use of ion mobility for extraction of glycan profiles from such samples and for obtaining clean CID spectra when targeted m/z values capture additional ions from those of the target compound. N-glycans were released enzymatically from within SDS-PAGE gels, from the representative recombinant glycoprotein, gp120 of the human immunodeficiency virus, and examined by direct infusion electrospray in negative mode followed by ion mobility with a Waters Synapt G2 mass spectrometer (Waters MS-Technologies, Manchester, UK). Clean profiles of singly, doubly, and triply charged N-glycans were obtained from samples in cases where the raw electrospray spectra displayed only a few glycan ions as the result of low sample concentration or the presence of contamination. Ion mobility also enabled uncontaminated CID spectra to be obtained from glycans when their molecular ions displayed coincidence with ions from fragments or multiply charged ions with similar m/z values. This technique proved to be invaluable for removing extraneous ions from many CID spectra. The presence of such ions often produces spectra that are difficult to interpret. Most CID spectra, even those from abundant glycan constituents, benefited from such clean-up, showing that the extra dimension provided by ion mobility was invaluable for studies of this type.

  5. Ion Mobility Mass Spectrometry for Ion Recovery and Clean-Up of MS and MS/MS Spectra Obtained from Low Abundance Viral Samples.

    PubMed

    Harvey, David J; Crispin, Max; Bonomelli, Camille; Scrivens, Jim H

    2015-10-01

    Many samples of complex mixtures of N-glycans released from small amounts of material, such as glycoproteins from viruses, present problems for mass spectrometric analysis because of the presence of contaminating material that is difficult to remove by conventional methods without involving sample loss. This study describes the use of ion mobility for extraction of glycan profiles from such samples and for obtaining clean CID spectra when targeted m/z values capture additional ions from those of the target compound. N-glycans were released enzymatically from within SDS-PAGE gels, from the representative recombinant glycoprotein, gp120 of the human immunodeficiency virus, and examined by direct infusion electrospray in negative mode followed by ion mobility with a Waters Synapt G2 mass spectrometer (Waters MS-Technologies, Manchester, UK). Clean profiles of singly, doubly, and triply charged N-glycans were obtained from samples in cases where the raw electrospray spectra displayed only a few glycan ions as the result of low sample concentration or the presence of contamination. Ion mobility also enabled uncontaminated CID spectra to be obtained from glycans when their molecular ions displayed coincidence with ions from fragments or multiply charged ions with similar m/z values. This technique proved to be invaluable for removing extraneous ions from many CID spectra. The presence of such ions often produces spectra that are difficult to interpret. Most CID spectra, even those from abundant glycan constituents, benefited from such clean-up, showing that the extra dimension provided by ion mobility was invaluable for studies of this type.

  6. Can we trust mass spectrometry for determination of arsenic peptides in plants: comparison of LC-ICP-MS and LC-ES-MS/ICP-MS with XANES/EXAFS in analysis of Thunbergia alata.

    PubMed

    Bluemlein, Katharina; Raab, Andrea; Meharg, Andrew A; Charnock, John M; Feldmann, Jörg

    2008-04-01

    The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP-MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L(-1) as arsenate. The approach of formic acid extraction followed by HPLC-ES-MS/ICP-MS identified different As(III)-PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible. Although sulfur sensitivity could be significantly increased when xenon was used as collision gas in ICP-qMS, or when HR-ICP-MS was used in medium resolution, the As:S ratio gave misleading results in the identification of As(III)-PC complexes due to the relatively low resolution of the chromatography system in relation to the variety of As-peptides in plants. Hence only the parallel use of ES-MS/ICP-MS was able to prove the occurrence of such arsenite phytochelatin complexes. Between 55 and 64% of the arsenic was bound to the sulfur of peptides mainly as As(III)(PC(2))(2), As(III)(PC(3)) and As(III)(PC(4)). XANES (X-ray absorption near-edge spectroscopy) measurement, using the freshly exposed plant root directly, confirmed that most of the arsenic is trivalent and binds to S of peptides (53% As-S) while 38% occurred as arsenite and only 9% unchanged as arsenate. EXAFS data confirmed that As-S and As-O bonds occur in the plants. This study confirms, for the first time, that As-peptides can be extracted by formic acid and chromatographically separated on a reversed-phase column without significant decomposition or de-novo synthesis during the extraction step. PMID:18084749

  7. Can we trust mass spectrometry for determination of arsenic peptides in plants: comparison of LC-ICP-MS and LC-ES-MS/ICP-MS with XANES/EXAFS in analysis of Thunbergia alata.

    PubMed

    Bluemlein, Katharina; Raab, Andrea; Meharg, Andrew A; Charnock, John M; Feldmann, Jörg

    2008-04-01

    The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP-MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L(-1) as arsenate. The approach of formic acid extraction followed by HPLC-ES-MS/ICP-MS identified different As(III)-PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible. Although sulfur sensitivity could be significantly increased when xenon was used as collision gas in ICP-qMS, or when HR-ICP-MS was used in medium resolution, the As:S ratio gave misleading results in the identification of As(III)-PC complexes due to the relatively low resolution of the chromatography system in relation to the variety of As-peptides in plants. Hence only the parallel use of ES-MS/ICP-MS was able to prove the occurrence of such arsenite phytochelatin complexes. Between 55 and 64% of the arsenic was bound to the sulfur of peptides mainly as As(III)(PC(2))(2), As(III)(PC(3)) and As(III)(PC(4)). XANES (X-ray absorption near-edge spectroscopy) measurement, using the freshly exposed plant root directly, confirmed that most of the arsenic is trivalent and binds to S of peptides (53% As-S) while 38% occurred as arsenite and only 9% unchanged as arsenate. EXAFS data confirmed that As-S and As-O bonds occur in the plants. This study confirms, for the first time, that As-peptides can be extracted by formic acid and chromatographically separated on a reversed-phase column without significant decomposition or de-novo synthesis during the extraction step.

  8. One step derivatization with British Anti-Lewsite in combination with gas chromatography coupled to triple-quadrupole tandem mass spectrometry for the fast and selective analysis of inorganic arsenic in rice.

    PubMed

    Kang, Ju Hui; Jung, Hyun Jeong; Jung, Mun Yhung

    2016-08-31

    We developed a new fast and selective analytical method for the determination of inorganic arsenic (iAs) in rice by a gas chromatography - tandem mass spectrometry (GC-MS/MS) in combination with one step derivatization of inorganic arsenic (iAs) with British Anti-Lewsite (BAL). Two step derivatization of iAs with BAL has been previously performed for the GC-MS analysis. In this paper, the quantitative one step derivatization condition was successfully established. The GC-MS/MS was carried out with a short nonpolar capillary column (0.25 mm × 10 m) under the conditions of fast oven temperature ramp rate (4 °C/s) and high linear velocity (108.8 cm/s) of the carrier gas. The established GC-MS/MS method showed an excellent linearity (r(2) > 0.999) in a tested range (0.2-100.0 μg L(-1)), ultra-low limit of detection (LOD, 0.08 pg), and high precision and accuracy. The GC-MS/MS technique showed far greater selectivity (22.5 fold higher signal to noise ratio in rice sample) on iAs than GC-MS method. The gas chromatographic running time was only 2.5 min with the iAs retention time of 1.98 min. The established method was successfully applied to quantify the iAs contents in polished rice. The mean iAs content in the Korean polished rice (n = 27) was 66.1 μg kg(-1) with the range of 37.5-125.0 μg kg(-1). This represents the first report on the GC-tandem mass spectrometry in combination with the one step derivatization with BAL for the iAs speciation in rice. This GC-MS/MS method would be a simple, useful and reliable measure for the iAs analysis in rice in the laboratories in which the expensive and element specific HPLC-ICP-MS is not available. PMID:27506365

  9. Aqueous phase oligomerization of α,β-unsaturated carbonyls and acids investigated using ion mobility spectrometry coupled to mass spectrometry (IMS-MS)

    NASA Astrophysics Data System (ADS)

    Renard, Pascal; Tlili, Sabrine; Ravier, Sylvain; Quivet, Etienne; Monod, Anne

    2016-04-01

    One of the current essential issues to unravel our ability to forecast future climate change and air quality, implies a better understanding of natural processes leading to secondary organic aerosol (SOA) formation, and in particular the formation and fate of oligomers. The difficulty in characterizing macromolecules is to discern between large oxygenated molecules from series of oligomers containing repeated small monomers of diverse structures. In the present study, taking advantage from previously established radical vinyl oligomerization of methyl vinylketone (MVK) in the aqueous phase, where relatively simple oligomers containing up to 14 monomers were observed, we have investigated the same reactivity on several other unsaturated water soluble organic compounds (UWSOCs) and on a few mixtures of these precursor compounds. The technique used to characterize the formed oligomers was a traveling wave ion mobility spectrometry coupled to a hybrid quadrupole - time of flight mass spectrometer (IMS-MS) fitted with an electrospray source and ultra-high performance liquid chromatography (UPLC). The technique allows for an additional separation, especially for large ions, containing long carbon chains. We have shown the efficiency of the IMS-mass spectrometry technique to detect oligomers derived from MVK photooxidation in the aqueous phase. The results were then compared to other oligomers, derived from ten other individual biogenic UWSOCs. The technique allowed distinguishing between different oligomers arising from different precursors. It also clearly showed that compounds bearing a non-conjugated unsaturation did not provide oligomerization. Finally, it was shown that the IMS-mass spectrometry technique, applied to mixtures of unsaturated conjugated precursors, exhibited the ability of these precursors to co-oligomerize, i.e. forming only one complex oligomer system bearing monomers of different structures. The results are discussed in terms of atmospheric

  10. Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS)

    PubMed Central

    Broeckling, Corey D.; Heuberger, Adam L.; Prenni, Jessica E.

    2013-01-01

    Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. The approach offers an unbiased and in-depth analysis that can enable the development of diagnostic tests, novel therapies, and further our understanding of disease processes. The inherent chemical diversity of the metabolome creates significant analytical challenges and there is no single experimental approach that can detect all metabolites. Additionally, the biological variation in individual metabolism and the dependence of metabolism on environmental factors necessitates large sample numbers to achieve the appropriate statistical power required for meaningful biological interpretation. To address these challenges, this tutorial outlines an analytical workflow for large scale non-targeted metabolite profiling of serum by UPLC-MS. The procedure includes guidelines for sample organization and preparation, data acquisition, quality control, and metabolite identification and will enable reliable acquisition of data for large experiments and provide a starting point for laboratories new to non-targeted metabolite profiling by UPLC-MS. PMID:23524330

  11. msIQuant--Quantitation Software for Mass Spectrometry Imaging Enabling Fast Access, Visualization, and Analysis of Large Data Sets.

    PubMed

    Källback, Patrik; Nilsson, Anna; Shariatgorji, Mohammadreza; Andrén, Per E

    2016-04-19

    This paper presents msIQuant, a novel instrument- and manufacturer-independent quantitative mass spectrometry imaging software suite that uses the standardized open access data format imzML. Its data processing structure enables rapid image display and the analysis of very large data sets (>50 GB) without any data reduction. In addition, msIQuant provides many tools for image visualization including multiple interpolation methods, low intensity transparency display, and image fusion. It also has a quantitation function that automatically generates calibration standard curves from series of standards that can be used to determine the concentrations of specific analytes. Regions-of-interest in a tissue section can be analyzed based on a number of quantities including the number of pixels, average intensity, standard deviation of intensity, and median and quartile intensities. Moreover, the suite's export functions enable simplified postprocessing of data and report creation. We demonstrate its potential through several applications including the quantitation of small molecules such as drugs and neurotransmitters. The msIQuant suite is a powerful tool for accessing and evaluating very large data sets, quantifying drugs and endogenous compounds in tissue areas of interest, and for processing mass spectra and images.

  12. Bioimaging of metals in brain tissue by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and metallomics.

    PubMed

    Becker, J Sabine; Matusch, Andreas; Palm, Christoph; Salber, Dagmar; Morton, Kathryn A; Becker, J Susanne

    2010-02-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been developed and established as an emerging technique in the generation of quantitative images of metal distributions in thin tissue sections of brain samples (such as human, rat and mouse brain), with applications in research related to neurodegenerative disorders. A new analytical protocol is described which includes sample preparation by cryo-cutting of thin tissue sections and matrix-matched laboratory standards, mass spectrometric measurements, data acquisition, and quantitative analysis. Specific examples of the bioimaging of metal distributions in normal rodent brains are provided. Differences to the normal were assessed in a Parkinson's disease and a stroke brain model. Furthermore, changes during normal aging were studied. Powerful analytical techniques are also required for the determination and characterization of metal-containing proteins within a large pool of proteins, e.g., after denaturing or non-denaturing electrophoretic separation of proteins in one-dimensional and two-dimensional gels. LA-ICP-MS can be employed to detect metalloproteins in protein bands or spots separated after gel electrophoresis. MALDI-MS can then be used to identify specific metal-containing proteins in these bands or spots. The combination of these techniques is described in the second section.

  13. Precise Re isotope ratio measurements by negative thermal ionization mass spectrometry (NTI-MS) using total evaporation technique

    NASA Astrophysics Data System (ADS)

    Suzuki, Katsuhiko; Miyata, Yoshiki; Kanazawa, Nobuyuki

    2004-06-01

    High precision rhenium isotope ratios, 187Re/185Re, have been determined by negative thermal ionization mass spectrometry (NTI-MS) using a total evaporation technique. The salient features of this method are evaporation of the entire sample and simultaneous integration of the signal from each isotope, which effectively eliminates isotope fractionation effects during the evaporation process. The 187Re/185Re ratio is obtained with a high reproducibility (1.6755+/-0.0014 (2[sigma]), R.S.D.=0.083%, n=28) for 50 pg-1 ng of a Re natural standard using the total evaporation with NTI-MS. This value is within analytical uncertainty of the previously reported accurate 187Re/185Re ratio (1.6740+/-0.0011) adopted by IUPAC as the Re isotopic composition, and is significantly more precise than the ratio obtained from conventional NTI-MS isotopic measurements in our laboratory (1.6772+/-0.0037 (2[sigma]), R.S.D.=0.22%, n=34). Based on these results, the total evaporation technique allows us to precisely determine Re isotope ratios, even for small sample amounts. In addition, this method is effective for highly precise Re abundance determinations using isotope dilution.

  14. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS)

    SciTech Connect

    Browner, R.F.

    1990-10-01

    Accomplishments on the fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry (LC/MS) interface during the period 1 December 1989 to 30 November 1990 are summarized. In order to determine the influence of temperature on the vaporization and decomposition properties of molecules, test have been carried out on both thermally stable and thermally labile molecules. The test compounds used were a series of polynuclear aromatic (PAH) compounds covering a wide range of molecular weights from two-ring naphthalene to twelve-ring perylene. The less thermally stable species examined were aldicarb, a highly thermally labile pesticide, and cholesterol, which readily loses water when subjected to high temperatures. A new, externally heated probe, which can be raised to temperatures as high as 500{degree}C was also used. Matrix loading effects for a range of surface active and non-surface active compounds in three different matrices: glycerol, 3-nitrobenzyl alcohol, and thioglycerol for fast atom bombardment (FAB) particle beam LC/MS have been studied. The time dependence of FAB spectra generation in the particle beam system has been examined and contrasted with ion generation in normal probe FAB work. Future FAB LC/MS research is outlined. 3 refs. (BM)

  15. Mass Spectrometry Imaging and GC-MS Profiling of the Mammalian Peripheral Sensory-Motor Circuit.

    PubMed

    Rubakhin, Stanislav S; Ulanov, Alexander; Sweedler, Jonathan V

    2015-06-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has evolved to become an effective discovery tool in science and clinical diagnostics. Here, chemical imaging approaches are applied to well-defined regions of the mammalian peripheral sensory-motor system, including the dorsal root ganglia (DRG) and adjacent nerves. By combining several MSI approaches, analyte coverage is increased and 195 distinct molecular features are observed. Principal component analysis suggests three chemically different regions within the sensory-motor system, with the DRG and adjacent nerve regions being the most distinct. Investigation of these regions using gas chromatography-mass spectrometry corroborate these findings and reveal important metabolic markers related to the observed differences. The heterogeneity of the structurally, physiologically, and functionally connected regions demonstrates the intricate chemical and spatial regulation of their chemical composition.

  16. Mass Spectrometry Imaging and GC-MS Profiling of the Mammalian Peripheral Sensory-Motor Circuit

    NASA Astrophysics Data System (ADS)

    Rubakhin, Stanislav S.; Ulanov, Alexander; Sweedler, Jonathan V.

    2015-06-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has evolved to become an effective discovery tool in science and clinical diagnostics. Here, chemical imaging approaches are applied to well-defined regions of the mammalian peripheral sensory-motor system, including the dorsal root ganglia (DRG) and adjacent nerves. By combining several MSI approaches, analyte coverage is increased and 195 distinct molecular features are observed. Principal component analysis suggests three chemically different regions within the sensory-motor system, with the DRG and adjacent nerve regions being the most distinct. Investigation of these regions using gas chromatography-mass spectrometry corroborate these findings and reveal important metabolic markers related to the observed differences. The heterogeneity of the structurally, physiologically, and functionally connected regions demonstrates the intricate chemical and spatial regulation of their chemical composition.

  17. Mass Spectrometry Imaging and GC-MS Profiling of the Mammalian Peripheral Sensory-Motor Circuit

    PubMed Central

    Rubakhin, Stanislav S.; Ulanov, Alexander; Sweedler, Jonathan V.

    2015-01-01

    Matrix-assisted laser desorption / ionization-mass spectrometry imaging (MSI) has evolved to become an effective discovery tool in science and clinical diagnostics. Here, chemical imaging approaches are applied to well-defined regions of the mammalian peripheral sensory-motor system, including the dorsal root ganglia (DRG) and adjacent nerves. By combining several MSI approaches, analyte coverage is increased and 195 distinct molecular features are observed. Principal component analysis suggests three chemically different regions within the sensory-motor system, with the DRG and adjacent nerve regions being the most distinct. Investigation of these regions using gas chromatography-mass spectrometry corroborate these findings and reveal important metabolic markers related to the observed differences. The heterogeneity of the structurally, physiologically, and functionally connected regions demonstrates the intricate chemical and spatial regulation of their chemical composition. PMID:25822927

  18. Simultaneous determination of multi-mycotoxins in palm kernel cake (PKC) using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Yibadatihan, S; Jinap, S; Mahyudin, N A

    2014-01-01

    Palm kernel cake (PKC) is a useful source of protein and energy for livestock. Recently, it has been used as an ingredient in poultry feed. Mycotoxin contamination of PKC due to inappropriate handling during production and storage has increased public concern about economic losses and health risks for poultry and humans. This concern has accentuated the need for the evaluation of mycotoxins in PKC. Furthermore, a method for quantifying mycotoxins in PKC has so far not been established. The aims of this study were therefore (1) to develop a method for the simultaneous determination of mycotoxins in PKC and (2) to validate and verify the method. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using an electrospray ionisation interface (ESI) in both positive- and negative-ion modes was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T-2 and HT-2 toxin in PKC. An optimum method using a 0.2 ml min⁻¹ flow rate, 0.2% formic acid in aqueous phase, 10% organic phase at the beginning and 90% organic phase at the end of the gradient was achieved. The extraction of mycotoxins was performed using a solvent mixture of acetonitrile-water-formic acid (79:20:1, v/v) without further clean-up. The mean recoveries of mycotoxins in spiked PKC samples ranged from 81% to 112%. Limits of detection (LODs) and limits of quantification (LOQs) for mycotoxin standards and PKC samples ranged from 0.02 to 17.5 μg kg⁻¹ and from 0.06 to 58.0 μg kg⁻¹, respectively. Finally, the newly developed method was successfully applied to PKC samples. The results illustrated the fact that the method is efficient and accurate for the simultaneous multi-mycotoxin determination in PKC, which can be ideal for routine analysis. PMID:25396715

  19. Simultaneous determination of multi-mycotoxins in palm kernel cake (PKC) using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Yibadatihan, S; Jinap, S; Mahyudin, N A

    2014-01-01

    Palm kernel cake (PKC) is a useful source of protein and energy for livestock. Recently, it has been used as an ingredient in poultry feed. Mycotoxin contamination of PKC due to inappropriate handling during production and storage has increased public concern about economic losses and health risks for poultry and humans. This concern has accentuated the need for the evaluation of mycotoxins in PKC. Furthermore, a method for quantifying mycotoxins in PKC has so far not been established. The aims of this study were therefore (1) to develop a method for the simultaneous determination of mycotoxins in PKC and (2) to validate and verify the method. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using an electrospray ionisation interface (ESI) in both positive- and negative-ion modes was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T-2 and HT-2 toxin in PKC. An optimum method using a 0.2 ml min⁻¹ flow rate, 0.2% formic acid in aqueous phase, 10% organic phase at the beginning and 90% organic phase at the end of the gradient was achieved. The extraction of mycotoxins was performed using a solvent mixture of acetonitrile-water-formic acid (79:20:1, v/v) without further clean-up. The mean recoveries of mycotoxins in spiked PKC samples ranged from 81% to 112%. Limits of detection (LODs) and limits of quantification (LOQs) for mycotoxin standards and PKC samples ranged from 0.02 to 17.5 μg kg⁻¹ and from 0.06 to 58.0 μg kg⁻¹, respectively. Finally, the newly developed method was successfully applied to PKC samples. The results illustrated the fact that the method is efficient and accurate for the simultaneous multi-mycotoxin determination in PKC, which can be ideal for routine analysis.

  20. Determination of caramel colorants' by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

    PubMed

    Goscinny, Séverine; Hanot, Vincent; Trabelsi, Hasna; Van Loco, Joris

    2014-01-01

    2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml⁻¹ (LOQ) to 500 ng ml⁻¹ with recoveries of 75.4-112.4% and RSDs of 1.5-15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25-30 µg ml⁻¹ with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml⁻¹. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml⁻¹). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml⁻¹), which required a high level of dilution before following the standard addition protocol.

  1. Two complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods to study the excretion and metabolic interaction of edaravone and taurine in rats.

    PubMed

    Tang, Dao-quan; Zheng, Xiao-xiao; Li, Yin-jie; Bian, Ting-ting; Yu, Yan-yan; Du, Qian; Yang, Dong-zhi; Jiang, Shui-shi

    2014-11-01

    In this study, two independent and complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were respectively developed and validated for the determination of edaravone or taurine in rat urine, feces and bile after intravenous administration, using 3-methyl-l-p-tolyl-5-pyrazolone and sulfanilic acid as the internal standards (IS). Edaravone was separated on an Agilent Eclipse Plus C18 column (100×2.1 mm, 3.5 μm) using methanol and water (containing 5 mM ammonium formate and 0.02% formic acid) as mobile phase, while taurine was performed on a Waters Atlantis HILIC Silica column (150×2.1 mm, 3 μm) using acetonitrile and water (containing 5mM ammonium formate and 0.2% formic acid) as mobile phase. The mass analysis was performed in a Triple Quadrupole mass spectrometer via multiple reaction monitoring (MRM) with negative ionization mode. The optimized mass transition ion pairs (m/z) for quantification were 173.1→92.2 and 187.2→106.0 for edaravone and its IS, 124.1→80.0 and 172.0→80.0 for taurine and its IS, respectively. The validated methods have been successfully applied to the excretion and metabolism interaction study of edaravone and taurine in rats after independent intravenous administration and co-administration with a single dose. The results demonstrated that there were no significant alternations on the metabolism and cumulative excretion rate of edaravone and taurine, implying that the proposed combination therapy was pharmacologically viable.

  2. Protein turnover measurement using selected reaction monitoring-mass spectrometry (SRM-MS)

    PubMed Central

    Holman, Stephen W.; Hammond, Dean E.; Simpson, Deborah M.; Waters, John; Hurst, Jane L.

    2016-01-01

    Protein turnover represents an important mechanism in the functioning of cells, with deregulated synthesis and degradation of proteins implicated in many diseased states. Therefore, proteomics strategies to measure turnover rates with high confidence are of vital importance to understanding many biological processes. In this study, the more widely used approach of non-targeted precursor ion signal intensity (MS1) quantification is compared with selected reaction monitoring (SRM), a data acquisition strategy that records data for specific peptides, to determine if improved quantitative data would be obtained using a targeted quantification approach. Using mouse liver as a model system, turnover measurement of four tricarboxylic acid cycle proteins was performed using both MS1 and SRM quantification strategies. SRM outperformed MS1 in terms of sensitivity and selectivity of measurement, allowing more confident determination of protein turnover rates. SRM data are acquired using cheaper and more widely available tandem quadrupole mass spectrometers, making the approach accessible to a larger number of researchers than MS1 quantification, which is best performed on high mass resolution instruments. SRM acquisition is ideally suited to focused studies where the turnover of tens of proteins is measured, making it applicable in determining the dynamics of proteins complexes and complete metabolic pathways. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644981

  3. Computer-aided method for identification of major flavone/flavonol glycosides by high-performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS).

    PubMed

    Wang, Zhengfang; Lin, Longze; Harnly, James M; Harrington, Peter de B; Chen, Pei

    2014-11-01

    A new computational tool is proposed here for tentatively identifying major (UV quantifiable) flavone/flavonol glycoside peaks of high performance liquid chromatogram (HPLC)-diode array detection (DAD)-tandem mass spectrometry (MS/MS) profiles based on a MATLAB-based script implementing an in-house algorithm. The HPLC-DAD-MS/MS profiles of red onion, Chinese lettuce, carrot leaf, and celery seed extracts were analyzed by the proposed computer-aided screening method for identifying possible flavone/flavonol glycoside peaks from the HPLC-UV and MS total ion current (TIC) chromatograms. The number of identified flavone/flavonol glycoside peaks of the HPLC-UV chromatograms is four, four, six, and nine for red onion, Chinese lettuce, carrot leaf, and celery seed, respectively. These results have been validated by human(s) experts. For the batch processing of nine HPLC-DAD-MS/MS profiles of celery seed extract, the entire script execution time was within 15 s while manual calculation of only one HPLC-DAD-MS/MS profile by a flavonoid expert could take hours. Therefore, this MATLAB-based screening method is able to facilitate the HPLC-DAD-MS/MS analysis of flavone/flavonol glycosides in plants to a large extent.

  4. Computer-aided method for identification of major flavone/flavonol glycosides by high-performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS).

    PubMed

    Wang, Zhengfang; Lin, Longze; Harnly, James M; Harrington, Peter de B; Chen, Pei

    2014-11-01

    A new computational tool is proposed here for tentatively identifying major (UV quantifiable) flavone/flavonol glycoside peaks of high performance liquid chromatogram (HPLC)-diode array detection (DAD)-tandem mass spectrometry (MS/MS) profiles based on a MATLAB-based script implementing an in-house algorithm. The HPLC-DAD-MS/MS profiles of red onion, Chinese lettuce, carrot leaf, and celery seed extracts were analyzed by the proposed computer-aided screening method for identifying possible flavone/flavonol glycoside peaks from the HPLC-UV and MS total ion current (TIC) chromatograms. The number of identified flavone/flavonol glycoside peaks of the HPLC-UV chromatograms is four, four, six, and nine for red onion, Chinese lettuce, carrot leaf, and celery seed, respectively. These results have been validated by human(s) experts. For the batch processing of nine HPLC-DAD-MS/MS profiles of celery seed extract, the entire script execution time was within 15 s while manual calculation of only one HPLC-DAD-MS/MS profile by a flavonoid expert could take hours. Therefore, this MATLAB-based screening method is able to facilitate the HPLC-DAD-MS/MS analysis of flavone/flavonol glycosides in plants to a large extent. PMID:25270867

  5. Characterization of Two Different Clay Materials by Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dilatometry (DIL) and Mass Spectrometry (MS) - 12215

    SciTech Connect

    Post, Ekkehard; Henderson, Jack B.

    2012-07-01

    An illitic clay containing higher amounts of organic materials was investigated by dilatometry, thermogravimetry and differential scanning calorimetric. The evolved gases were studied during simultaneous TG-DSC (STA) and dilatometer measurements with simultaneous mass spectrometry in inert gas and oxidizing atmosphere. The dilatometer results were compared with the STA-MS results which confirmed and explained the reactions found during heating of the clay, like dehydration, dehydroxylation, shrinkage, sintering, quartz phase transition, combustion or pyrolysis of organics and the solid state reactions forming meta-kaolinite and mullite. The high amount of organic material effects in inert gas atmosphere most probably a reduction of the oxides which leads to a higher mass loss than in oxidizing atmosphere. Due to this reduction an additional CO{sub 2} emission at around 1000 deg. C was detected which did not occur in oxidizing atmosphere. Furthermore TG-MS results of a clay containing alkali nitrates show that during heating, in addition to water and CO{sub 2}, NO and NO{sub 2} are also evolved, leading to additional mass loss steps. These types of clays showed water loss starting around 100 deg. C or even earlier. This relative small mass loss affects only less shrinkage during the expansion of the sample. The dehydroxylation and the high crystalline quartz content result in considerable shrinkage and expansion of the clay. During the usual solid state reaction where the clay structure collapses, the remaining material finally shrinks down to a so-called clinker. With the help of MS the TG steps can be better interpreted as the evolved gases are identified. With the help of the MS it is possible to distinguish between CO{sub 2} and water (carbonate decomposition, oxidation of organics or dehydration/dehydroxylation). The MS also clearly shows that mass number 44 is found during the TG step of the illitic clay at about 900 deg. C in inert gas, which was interpreted

  6. Detection of gunshot residue in blowfly larvae and decomposing porcine tissue using inductively coupled plasma mass spectrometry (ICP-MS).

    PubMed

    Lagoo, Lisa; Schaeffer, Luther S; Szymanski, David W; Smith, Ruth Waddell

    2010-05-01

    Blowfly larvae and porcine tissue contaminated with gunshot residue (GSR) were collected during summer and winter months, over a 37-day and a 60-day sampling period, respectively. Wound samples were microwave-digested and analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for the detection of antimony, barium, and lead. During summer, the 37-day sampling period encompassed all stages of decomposition, except skeletonization. The three elements were detected in larvae only on days 3 and 4 after death but were detected at significant levels in tissue samples throughout the entire sampling period. In winter, no significant decomposition was observed throughout the 60-day sampling. Although temperatures were too low for blowfly activity, the three elements were detected in the tissue samples at relatively constant, significant levels. Hence, GSR determination in tissue was more dependent on decomposition stage rather than time since death.

  7. Comparative studies of Remazol Brillant Blue removal by immobilized organisms; investigation of metabolites by GC/MS and FTIR spectrometry.

    PubMed

    Akdogan, Hatice Ardag; Topuz, Merve Canpolat

    2015-01-01

    Reactive dyes are important chemical pollutants from textile industries. Treatment of effluents from dye-based industries poses a major problem, and biotreatment with white rot fungi seems to be a viable option. The biological treatment of synthetic dyes at a low cost and in the shortest possible time is used especially in dye and textile industries and leads to pollution in the wastewater dumped into the environment by these industries. For this study, decolorization of the recalcitrant dye Remazol Brilliant Blue R by immobilized Pleurotus ostreatus and Coprinus plicatilis was investigated. This dye was removed 100% (dye concentration: 10.0 mg/L) by both immobilized organisms. Extracellular ligninolytic enzyme activities were also measured during the decolorization. There was an attempt to identify metabolites with FTIR spectrometry and GC/MS at the end of the decolorization. These results indicated that the samples did not include any detectable metabolite. PMID:25905752

  8. Electrospun Nanofiber Mats as "Smart Surfaces" for Desorption Electrospray Ionization Mass Spectrometry (DESI MS)-Based Analysis and Imprint Imaging.

    PubMed

    Hemalatha, R G; Ganayee, Mohd Azhardin; Pradeep, T

    2016-06-01

    In this paper, desorption electrospray ionization mass spectrometry (DESI MS)-based molecular analysis and imprint imaging using electrospun nylon-6 nanofiber mats are demonstrated for various analytical contexts. Uniform mats of varying thicknesses composed of ∼200 nm diameter fibers were prepared using needleless electrospinning. Analytical applications requiring rapid understanding of the analytes in single drops, dyes, inks, and/or plant extracts incorporated directly into the nanofibers are discussed with illustrations. The possibility to imprint patterns made of printing inks, plant parts (such as petals, leaves, and slices of rhizomes), and fungal growth on fruits with their faithful reproductions on the nanofiber mats is illustrated with suitable examples. Metabolites were identified by tandem mass spectrometry data available in the literature and in databases. The results highlight the significance of electrospun nanofiber mats as smart surfaces to capture diverse classes of compounds for rapid detection or to imprint imaging under ambient conditions. Large surface area, appropriate chemical functionalities exposed, and easiness of desorption due to weaker interactions of the analyte species are the specific advantages of nanofibers for this application. PMID:27159150

  9. Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

    NASA Astrophysics Data System (ADS)

    Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

    2016-10-01

    Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

  10. Resonance-Enhanced Multiphoton Ionization Mass Spectrometry (REMPI-MS): Applications for Process Analysis

    NASA Astrophysics Data System (ADS)

    Streibel, Thorsten; Zimmermann, Ralf

    2014-06-01

    Process analysis is an emerging discipline in analytical sciences that poses special requirements on analytical techniques, especially when conducted in an online manner. Mass spectrometric methods seem exceedingly suitable for this task, particularly if a soft ionization method is applied. Resonance-enhanced multiphoton ionization (REMPI) in combination with time-of-flight mass spectrometry (TOFMS) provides a selective and sensitive means for monitoring (poly)aromatic compounds in process flows. The properties of REMPI and various variations of the ionization process are presented. The potential of REMPI for process analysis is highlighted with several examples, and drawbacks of the method are also noted. Applications of REMPI-TOFMS for the detection and monitoring of aromatic species in a large variety of combustion processes comprising flames, vehicle exhaust, and incinerators are discussed. New trends in technical development and combination with other analytical methods are brought forward.

  11. Coumarin and furanocoumarin quantitation in citrus peel via ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS).

    PubMed

    Dugrand, Audray; Olry, Alexandre; Duval, Thibault; Hehn, Alain; Froelicher, Yann; Bourgaud, Frédéric

    2013-11-13

    Coumarins and furanocoumarins are secondary metabolites commonly found in citrus plants. These molecules are allelochemical compounds in plants that have controversial effects on humans, such as phototoxicity and the commonly described interactions with drugs, referred to as the "grapefruit juice effect". Thus, it is important to develop a reliable method to identify and quantitate the coumarins and furanocoumarins in citrus extracts. For this purpose, we herein describe an ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS)-based method. We first developed a rapid UPLC method (20 min) to separate the isomers of each furanocoumarin. A subsequent single ion monitoring MS detection method was performed to distinguish between the molecules, which were possibly coeluting but had different molecular weights. The method was successfully used to separate and quantitate 6 coumarins and 21 furanocoumarins in variable amounts within peel extracts (flavedo and albedo) of 6 varieties of Citrus (sweet orange, lemon, grapefruit, bergamot, pummelo, and clementine). This method combines high selectivity and sensitivity in a rapid analysis and is useful for fingerprinting Citrus species via their coumarin and furanocoumarin contents.

  12. Analytical Approaches Based on Gas Chromatography Mass Spectrometry (GC/MS) to Study Organic Materials in Artworks and Archaeological Objects.

    PubMed

    Bonaduce, Ilaria; Ribechini, Erika; Modugno, Francesca; Colombini, Maria Perla

    2016-02-01

    Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects. The latest progresses in advancing analytical approaches, characterising materials and understanding their degradation, and developing methods for monitoring their stability are discussed. Case studies from the literature are presented to examine how the choice of the working conditions and the analytical approaches is driven by the analytical and technical question to be answered, as well as the nature of the object from which the samples are collected. PMID:27572989

  13. Multi-elemental analysis of aqueous geochemical samples by quadrupole inductively coupled plasma-mass spectrometry (ICP-MS)

    USGS Publications Warehouse

    Wolf, Ruth E.; Adams, Monique

    2015-01-01

    Typically, quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) is used to determine as many as 57 major, minor, and trace elements in aqueous geochemical samples, including natural surface water and groundwater, acid mine drainage water, and extracts or leachates from geological samples. The sample solution is aspirated into the inductively coupled plasma (ICP) which is an electrodeless discharge of ionized argon gas at a temperature of approximately 6,000 degrees Celsius. The elements in the sample solution are subsequently volatilized, atomized, and ionized by the ICP. The ions generated are then focused and introduced into a quadrupole mass filter which only allows one mass to reach the detector at a given moment in time. As the settings of the mass analyzer change, subsequent masses are allowed to impact the detector. Although the typical quadrupole ICP-MS system is a sequential scanning instrument (determining each mass separately), the scan speed of modern instruments is on the order of several thousand masses per second. Consequently, typical total sample analysis times of 2–3 minutes are readily achievable for up to 57 elements.

  14. Analytical Approaches Based on Gas Chromatography Mass Spectrometry (GC/MS) to Study Organic Materials in Artworks and Archaeological Objects.

    PubMed

    Bonaduce, Ilaria; Ribechini, Erika; Modugno, Francesca; Colombini, Maria Perla

    2016-02-01

    Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects. The latest progresses in advancing analytical approaches, characterising materials and understanding their degradation, and developing methods for monitoring their stability are discussed. Case studies from the literature are presented to examine how the choice of the working conditions and the analytical approaches is driven by the analytical and technical question to be answered, as well as the nature of the object from which the samples are collected.

  15. Determination of phenobarbital in hair matrix by liquid phase microextraction (LPME) and gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Roveri, Flávia Lopes; Paranhos, Beatriz Aparecida Passos Bismara; Yonamine, Mauricio

    2016-08-01

    A method for identification and quantification of phenobarbital in hair samples by liquid phase microextraction (LPME) and gas chromatography-mass spectrometry (GC-MS) has been presented. Drug-free hair specimens were collected and separated in 50mg aliquots. Each aliquot was washed with 2.0mL of dichloromethane for 15min at 37°C. Standards and deuterated internal standards for calibration and quality control samples were added to the washed hair aliquot and the sample was submitted to complete digestion with sodium hydroxide (NaOH) 1.0mol/L for 15min at 70°C. The dissolved sample was submitted to LPME. After extraction, the residue was derivatized with tetramethylammonium hydroxide (TMAH) and analyzed by GC-MS. The limit of detection (LOD) was 0.1ng/mg and the limit of quantification (LOQ) was 0.25ng/mg. The calibration curve was linear over a concentration range of 0.25ng/mg to 10ng/mg (r(2)>0.99). The intra- and inter-assay precisions, given by RSD, were less than 6% for phenobarbital. Fortified samples of secobarbital and pentobarbital were also submitted to the validated method. The method was successfully applied to hair samples collected from three volunteers who reported regular use of phenobarbital (clinical treatment). The concentrations found were 9.5, 15.1 and 16.3ng/mg of phenobarbital. To contemplate the concentrations found, dilution integrity tests were also validated. The LPME and GC-MS method showed to be suitable for the detection of phenobarbital in hair samples and can be promptly used for different purposes whenever required. PMID:26829332

  16. Measurement of atmospheric sesquiterpenes by proton transfer reaction-mass spectrometry (PTR-MS)

    NASA Astrophysics Data System (ADS)

    Kim, S.; Karl, T.; Helmig, D.; Daly, R.; Rasmussen, R.; Guenther, A.

    2008-12-01

    The ability to measure sesquiterpenes (SQT; C15H24) by a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) was investigated with SQT standards, prepared by a capillary diffusion method, and the estimated mixing ratios, derived from the counts of product ions and proton transfer reaction constants were intercompared with measured mixing ratios, measured by a complementary Gas Chromatograph (GC) coupled to a Flame Ionization Detector (GC-FID). Product ion distributions due to soft-ionization occurring in a selected ion drift tube via proton transfer were measured as a function of collision energies. Results after the consideration of the mass discrimination of the PTR-MS system suggest that quantitative SQT measurements within 20% accuracy can be achieved with PTR-MS if two major product ions (m/z 149+ and 205+) out of seven major product ions (m/z 81+, 95+, 109+, 123+, 135+, 149+ and 205+) are accounted for. Bicyclic sesquiterpenes, i.e. β-caryophyllene and α-humulene, showed considerable fragmentation causing the accuracy of their analysis to be reduced to 50% if only the parent ion (m/z 205) is considered. These findings were applied to a field dataset collected above a deciduous forest at the PROPHET (Program for Research on Oxidants: Photochemistry, Emissions, and Transport) research station in 2005. Inferred Average daytime ecosystem scale mixing ratios (fluxes) of isoprene, sum of monoterpenes (MT), and sum of SQT exhibited values of 15 μg m-3 (4.5 mg m-2 h-1), 1.2 μg m-3 (0.21 mg m-2 h-1) and 0.0016 μg m-3 (0.10 mgm-2 h-1) respectively. A range of MT and SQT reactivities with respect to the OH radical was calculated and compared to an earlier study inferring significantly underestimated OH reactivities due to unknown terpenes above this deciduous forest. The results indicate that MT and SQT can resolve ~30% of missing OH reactivity, reported from this site.

  17. Investigation on pharmacokinetics, tissue distribution and excretion of 1-triacontanol in rats by gas chromatography-tandem mass spectrometry (GC-MS/MS).

    PubMed

    Wang, Chunfeng; Fan, Ali; Deng, Shuhua; Gao, Wenchao; Zhang, Wei; Yang, Wei; Zhu, Xiaojie; Lu, Yang; Chen, Xijing

    2015-01-01

    1. 1-Triacontanol (TA) recently shows promising anti-tumor activity. The present study was aimed to develop a sensitive gas chromatography-tandem mass spectrometry method to explore the pharmacokinetic profiles, distribution and excretion of TA in Sprague-Dawley rats after oral administration of TA. Chromatography separation was performed on a HP-5MS column. 1-Octacosanal was used as the internal standard (IS). Quantification of TA and IS was carried out at m/z 495.6 → 97.0 and m/z 467.5 → 97.0, respectively, in positive electron ionization and multiple reaction monitoring mode. The pharmacokinetic parameters were calculated by non-compartmental analysis. 2. The area under concentration-time curve AUC0-6 h and AUC0-∞ for TA at 60 mg/kg were 87.737 ± 13.574 and 93.617 ± 17.62, respectively. The mean residence time was 3.25 ± 0.17 h. In addition, the elimination half-lives (t1/2) were (2.37 ± 1.23, 1.27 ± 0.49, 2.07 ± 0.93) h after single oral administration of 30, 60 and 120 mg/kg of TA. After oral administration, TA was extensively distributed in stomach and intestine. The majority of TA excreted via feces, and its accumulative excretion ratio during the period of 72 h was 26.68 ± 7.14%, but only 0.0023 ± 0.0015% and 0.0027 ± 0.0006% for urines and bile, respectively. The absolute bioavailability (F, %) of TA was about 2.0%.

  18. Determination of multiple human arsenic metabolites employing high performance liquid chromatography inductively coupled plasma mass spectrometry.

    PubMed

    Stice, Szabina; Liu, Guangliang; Matulis, Shannon; Boise, Lawrence H; Cai, Yong

    2016-01-15

    During the metabolism of different arsenic-containing compounds in human, a variety of metabolites are produced with significantly varying toxicities. Currently available analytical methods can only detect a limited number of human metabolites in biological samples during one run due to their diverse characteristics. In addition, co-elution of species is often unnoticeable with most detection techniques leading to inaccurate metabolic profiles and assessment of toxicity. A high performance liquid chromatography inductively coupled mass spectrometry (HPLC-ICP-MS) method was developed that can identify thirteen common arsenic metabolites possibly present in human with special attention dedicated to thiolated or thiol conjugated arsenicals. The thirteen species included in this study are arsenite (As(III)), arsino-glutathione (As(GS)3), arsenate (As(V)), monomethylarsonous acid (MMA(III)), monomethylarsino-glutathione (MMA(III)(GS) 2), monomethylarsonic acid (MMA(V)), dimethylarsinous acid (DMA(III) (from DMA(III)I)), S-(dimethylarsinic)cysteine (DMA(III) (Cys)), dimethylarsino-glutathione (DMA(III)(GS)), dimethylarsinic acid (DMA(V)), dimethylmonothioarsinic acid (DMMTA(V)), dimethyldithioarsinic acid (DMDTA(V)), dimethylarsinothioyl glutathione (DMMTA(V)(GS)). The developed method was applied for the analysis of cancer cells that were incubated with darinaparsin (DMA(III)(GS)), a novel chemotherapeutic agent for refractory malignancies, and the arsenic metabolic profile obtained was compared to results using a previously developed method. This method provides a useful analytical tool which is much needed in unequivocally identifying the arsenicals formed during the metabolism of environmental arsenic exposure or therapeutic arsenic administration.

  19. METHOD 530 DETERMINATION OF SELECT SEMIVOLATILE ORGANIC CHEMICALS IN DRINKING WATER BY SOLID PHASE EXTRACTION AND GAS CHROMATOGRAPHY/ MASS SPECTROMETRY (GC/MS)

    EPA Science Inventory

    1.1. This is a gas chromatography/mass spectrometry (GC/MS) method for the determination of selected semivolatile organic compounds in drinking waters. Accuracy and precision data have been generated in reagent water, and in finished ground and surface waters for the compounds li...

  20. Quantitative Analysis of Bisphenol A Leached from Household Plastics by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (SPME-GC-MS)

    ERIC Educational Resources Information Center

    Johnson, Bettie Obi; Burke, Fernanda M.; Harrison, Rebecca; Burdette, Samantha

    2012-01-01

    The measurement of trace levels of bisphenol A (BPA) leached out of household plastics using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) is reported here. BPA is an endocrine-disrupting compound used in the industrial manufacture of polycarbonate plastic bottles and epoxy resin can liners. This experiment…

  1. DIFFERENTIATION OF AEROMONAS ISOLATES OBTAINED FROM DRINKING WATER DISTRIBUTION SYSTEM USING MATRIX-ASSISTED LASER DESCRIPTION/IONIZATION-MASS SPECTROMETRY (MALDI-MS)

    EPA Science Inventory

    The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the...

  2. Analysis of Phospholipid Mixtures from Biological Tissues by Matrix-Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS): A Laboratory Experiment

    ERIC Educational Resources Information Center

    Eibisch, Mandy; Fuchs, Beate; Schiller, Jurgen; Sub, Rosmarie; Teuber, Kristin

    2011-01-01

    Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used to investigate the phospholipid (PL) compositions of tissues and body fluids, often without previous separation of the total mixture into the individual PL classes. Therefore, the questions of whether all PL classes are detectable…

  3. A convenient method for calculation of ionic diffusion coefficients for accurate selected ion flow tube mass spectrometry, SIFT-MS

    NASA Astrophysics Data System (ADS)

    Dryahina, K.; Spanel, P.

    2005-07-01

    A method to calculate diffusion coefficients of ions important for the selected ion flow tube mass spectrometry, SIFT-MS, is presented. The ions, on which this method is demonstrated, include the SIFT-MS precursors H3O+(H2O)0,1,2,3, NO.+(H2O)0,1,2 and O2+ and the product ions relevant to analysis of breath trace metabolites ammonia (NH3+(H2O)0,1,2, NH4+(H2O)0,1,2), acetaldehyde (C2H4OH+(H2O)0,1,2), acetone (CH3CO+, (CH3)2CO+, (CH3)2COH+(H2O)0,1, (CH3)2CO.NO+), ethanol (C2H5OHH+(H2O)0,1,2) and isoprene (C5H7+, C5H8+, C5H9+). Theoretical model of the (12, 4) potential for interaction between the ions and the helium atoms is used, with the repulsive part approximated by the mean hard-sphere cross section and the attractive part describing ion-induced dipole interactions. The reduced zero-field mobilities at 300 K are calculated using the Viehland and Mason theory [L.A. Viehland, S.L. Lin, E.A. Mason, At. Data Nucl. Data Tables, 60 (1995) 37-95], parameterised by a simple formula as a function of the mean hard-sphere cross section, and converted to diffusion coefficients using the Einstein relation. The method is tested on a set of experimental data for simple ions and cluster ions.

  4. Estimation of honey authenticity by multielements characteristics using inductively coupled plasma-mass spectrometry (ICP-MS) combined with chemometrics.

    PubMed

    Chudzinska, M; Baralkiewicz, D

    2010-01-01

    In our study the mineral content of 55 honey samples, which represented three different types of honey: honeydew, buckwheat and rape honey from different areas in Poland, was evaluated. Determination of 13 elements (Al, B, Ba, Ca, Cd, Cu, K, Mg, Mn, Na, Ni, Pb, Zn) was performed using inductively coupled plasma-mass spectrometry. We tried to prove that the analysis of quality and quantity of honey elements could be used to define honey origin by using ICP-MS as a technique for simultaneous determination of elements. Chemometric methods, such as CA and PCA, were applied to classify honey according to mineral content. CA showed three clusters corresponding to the three botanical origins of honey. PCA permitted the reduction of 13 variables to four principal components explaining 77.19% of the total variance. The first most important principal component was strongly associated with the value of K, Al, Ni and Cd. This study revealed that CA and PCA analysis appear useful tools for differentiation of honey samples authenticity using the profile of mineral content and they highlighted the relationship between the elements distribution and honey type.

  5. A comprehensive characterisation of beer polyphenols by high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap-MS).

    PubMed

    Quifer-Rada, Paola; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Chiva-Blanch, Gemma; Jáuregui, Olga; Estruch, Ramon; Lamuela-Raventós, Rosa

    2015-02-15

    Beer is the second most consumed alcoholic beverage in Europe and shown by the European Prospective Investigation into Cancer and Nutrition cohort study to be the main food contributor to hydroxybenzoic acid intake. About 70-80% of the total polyphenol content in beer comes from malt, and the remaining 30-20% from hops. In this work, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique has been used for an accurate identification of beer polyphenols. 47 phenolic compounds were identified using high mass accuracy and confirmed by MS(2) experiments, including simple phenolic acids, hydroxycinnamoylquinics, flavanols, flavonols, flavones, alkylmethoxyphenols, alpha- and iso-alpha-acids, hydroxyphenylacetic acids and prenylflavonoids. As far as we know, 7 of these compounds have been recognised in beer for the first time: feruloylquinic acid, caffeic acid-O-hexoside, coumaric acid-O-hexoside, sinapic acid-O-hexoside, catechin-O-dihexoside, kaempferol-O-hexoside, and apigenin-C-hexoside-pentoside. PMID:25236235

  6. A comprehensive characterisation of beer polyphenols by high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap-MS).

    PubMed

    Quifer-Rada, Paola; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Chiva-Blanch, Gemma; Jáuregui, Olga; Estruch, Ramon; Lamuela-Raventós, Rosa

    2015-02-15

    Beer is the second most consumed alcoholic beverage in Europe and shown by the European Prospective Investigation into Cancer and Nutrition cohort study to be the main food contributor to hydroxybenzoic acid intake. About 70-80% of the total polyphenol content in beer comes from malt, and the remaining 30-20% from hops. In this work, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique has been used for an accurate identification of beer polyphenols. 47 phenolic compounds were identified using high mass accuracy and confirmed by MS(2) experiments, including simple phenolic acids, hydroxycinnamoylquinics, flavanols, flavonols, flavones, alkylmethoxyphenols, alpha- and iso-alpha-acids, hydroxyphenylacetic acids and prenylflavonoids. As far as we know, 7 of these compounds have been recognised in beer for the first time: feruloylquinic acid, caffeic acid-O-hexoside, coumaric acid-O-hexoside, sinapic acid-O-hexoside, catechin-O-dihexoside, kaempferol-O-hexoside, and apigenin-C-hexoside-pentoside.

  7. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study on colour stability of ovine meat.

    PubMed

    Subbaraj, Arvind K; Kim, Yuan H Brad; Fraser, Karl; Farouk, Mustafa M

    2016-07-01

    Meat colour is one of the cues available to the consumer to gauge overall meat quality and wholesomeness. Colour stability of meat is determined by several factors both inherent to the animal and post-slaughter conditions, including ageing, storage/packaging and display times. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study was undertaken to identify and compare polar metabolites between ovine meat samples that were exposed to different durations of ageing, storage conditions, and display times. Primary metabolites comprising amino acids, sugars, nucleotides, nucleosides, organic acids and their breakdown products were mainly identified as discriminating factors. For the first time, boron complexes of sugar and malic acid were also tentatively identified. As expected, most compounds identified were related to myoglobin chemistry, and compounds with antioxidant properties were found in higher levels in colour stable samples. Supplementary studies identifying semi-polar, non-polar and volatile compounds will provide a holistic understanding of the chemical basis of colour stability in ovine meat. PMID:26986230

  8. Identification of the country of growth of Sophora flavescens using direct analysis in real time mass spectrometry (DART-MS).

    PubMed

    Fukuda, Eriko; Uesawa, Yoshihiro; Baba, Masaki; Suzuki, Ryuichiro; Fukuda, Tatsuo; Shirataki, Yoshiaki; Okada, Yoshihito

    2014-11-01

    In order to identify the country of growth of Sophora flavescens by chemical fingerprinting, extracts of plants grown in China and Japan were analyzed using direct analysis in real time mass spectrometry (DART)-MS. The peaks characteristic of each country of growth were statistically analyzed using a volcano plot to summarize the relationship between the p-values of a statistical test and the magnitude of the difference in the peak intensities of the samples in the groups. Peaks with ap value < 0.05 in the t-test and a ≥ 2 absolute difference were defined as characteristic. Peaks characteristic of Chinese S. flavescens were found at m/z 439 and 440. In contrast, peaks characteristic of Japanese S. flavescens were found at m/z 313, 423, 437 and 441. The intensity of the selected peaks was similar in Japanese samples, whereas the m/z 439 peak had a significantly higher intensity than the other peaks in Chinese samples. Therefore, differences in selected peak patterns may allow identification of the country of growth of S. flavescens.

  9. Profiling of nonvolatiles in whiskeys using ultra high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS).

    PubMed

    Collins, Thomas S; Zweigenbaum, Jerry; Ebeler, Susan E

    2014-11-15

    Commercial samples of 63 American whiskeys, including bourbon whiskeys, Tennessee whiskeys, rye whiskeys and other blended whiskeys were analysed using ultra high pressure liquid chromatography (UHPLC) coupled with quadrupole time-of-flight (QTOF) mass spectrometry (MS). The non-volatile composition of the whiskeys was used to model differences among the samples using discriminant analysis. The blended American whiskeys were readily distinguished from the remaining types. Additionally, most Tennessee whiskeys could be differentiated from bourbon and rye whiskeys. Similarly, younger (<4 years old) and older (>8 years old) whiskeys could be separated. The compounds important for differentiating among these whiskeys included wood derived phenolic compounds, lignan derived compounds and several C8 and larger lipids. A number of additional compounds differentiated the whiskeys but could not be identified using MS and MS/MS data alone.

  10. Nanostructured indium tin oxide slides for small-molecule profiling and imaging mass spectrometry of metabolites by surface-assisted laser desorption ionization MS.

    PubMed

    López de Laorden, Carlos; Beloqui, Ana; Yate, Luis; Calvo, Javier; Puigivila, Maria; Llop, Jordi; Reichardt, Niels-Christian

    2015-01-01

    Due to their electrical conductivity and optical transparency, slides coated with a thin layer of indium tin oxide (ITO) are the standard substrate for protein imaging mass spectrometry on tissue samples by MALDI-TOF MS. We have now studied the rf magnetron sputtering deposition parameters to prepare ITO thin films on glass substrates with the required nanometric surface structure for their use in the matrix-free imaging of metabolites and small-molecule drugs, without affecting the transparency required for classical histology. The custom-made surfaces were characterized by atomic force microscopy, scanning electron microscopy, ellipsometry, UV, and laser desorption ionization MS (LDI-MS) and employed for the LDI-MS-based analysis of glycans and druglike molecules, the quantification of lactose in milk by isotopic dilution, and metabolite imaging on mouse brain tissue samples. PMID:25411795

  11. Profiling of nonvolatiles in whiskeys using ultra high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS).

    PubMed

    Collins, Thomas S; Zweigenbaum, Jerry; Ebeler, Susan E

    2014-11-15

    Commercial samples of 63 American whiskeys, including bourbon whiskeys, Tennessee whiskeys, rye whiskeys and other blended whiskeys were analysed using ultra high pressure liquid chromatography (UHPLC) coupled with quadrupole time-of-flight (QTOF) mass spectrometry (MS). The non-volatile composition of the whiskeys was used to model differences among the samples using discriminant analysis. The blended American whiskeys were readily distinguished from the remaining types. Additionally, most Tennessee whiskeys could be differentiated from bourbon and rye whiskeys. Similarly, younger (<4 years old) and older (>8 years old) whiskeys could be separated. The compounds important for differentiating among these whiskeys included wood derived phenolic compounds, lignan derived compounds and several C8 and larger lipids. A number of additional compounds differentiated the whiskeys but could not be identified using MS and MS/MS data alone. PMID:24912715

  12. Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography-Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods.

    PubMed

    Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; De Kimpe, Norbert; Matthijs, Bert; Le Bizec, Bruno

    2015-09-01

    The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (n = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair.

  13. Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography-Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods.

    PubMed

    Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; De Kimpe, Norbert; Matthijs, Bert; Le Bizec, Bruno

    2015-09-01

    The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (n = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair. PMID:26271751

  14. Direct identification of trypanosomatids by matrix-assisted laser desorption ionization-time of flight mass spectrometry (DIT MALDI-TOF MS).

    PubMed

    Avila, C C; Almeida, F G; Palmisano, G

    2016-08-01

    Accurate and rapid determination of trypanosomatids is essential in epidemiological surveillance and therapeutic studies. Matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) has been shown to be a useful and powerful technique to identify bacteria, fungi, metazoa and human intact cells with applications in clinical settings. Here, we developed and optimized a MALDI-TOF MS method to profile trypanosomatids. trypanosomatid cells were deposited on a MALDI target plate followed by addition of matrix solution. The plate was then subjected to MALDI-TOF MS measurement to create reference mass spectra library and unknown samples were identified by pattern matching using the BioTyper software tool. Several m/z peaks reproducibly and uniquely identified trypanosomatids species showing the potentials of direct identification of trypanosomatids by MALDI-TOF MS. Moreover, this method discriminated different life stages of Trypanosoma cruzi, epimastigote and bloodstream trypomastigote and Trypanosoma brucei, procyclic and bloodstream. T. cruzi Discrete Typing Units (DTUs) were also discriminated in three clades. However, it was not possible to achieve enough resolution and software-assisted identification at the strain level. Overall, this study shows the importance of MALDI-TOF MS for the direct identification of trypanosomatids and opens new avenues for mass spectrometry-based detection of parasites in biofluids. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27659938

  15. Identification and quantitation of amphetamine, methamphetamine, MDMA, pseudoephedrine, and ephedrine in blood, plasma, and serum using gas chromatography-mass spectrometry (GC/MS).

    PubMed

    Gunn, Josh; Kriger, Scott; Terrell, Andrea R

    2010-01-01

    Amphetamine, methamphetamine, MDMA, pseudoephedrine, and ephedrine are measured in blood, serum, and plasma using gas chromatography coupled to mass spectrometry (GC/MS). Following a simple liquid-liquid extraction, analytes are derivatized with heptafluorobutyric anhydride (HFBA) and 1 microL injected onto a HP-5MS 15-meter capillary column. Quantitation of each analyte is accomplished using a multi-point calibration curve and deuterated internal standards. The method provides a simple, robust, and reliable means to identify and measure these analytes.

  16. Analysis of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues in chlorine-treated water by gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS).

    PubMed

    Planas, Carles; Ventura, Francesc; Caixach, Josep; Martín, Jordi; Boleda, M Rosa; Paraira, Miquel

    2015-11-01

    A simple, selective and sensitive method for the analysis of the strong mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues (BMXs) in chlorine-treated water has been developed. The method is based on gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS), previous liquid-liquid extraction (LLE) of a smaller sample volume compared to other methods and on-line derivatization with a silylation reactive. GC-QqQ-MS/MS has been raised as an alternative easier to perform than gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) for the analysis of MX and BMXs, and it allows to achieve low LODs (0.3 ng/L for MX and 0.4-0.9 ng/L for BMXs). This technique had not been previously described for the analysis of MX and BMXs. Quality parameters were calculated and real samples related to 3 drinking water treatment plants (DWTPs), tap water and both untreated and chlorinated groundwater were analyzed. Concentrations of 0.3-6.6 ng/L for MX and 1.0-7.3 ng/L for BMXs were detected. Results were discussed according to five of the main factors affecting MX and BMXs formation in chlorine-treated water (organic precursors, influence of bromide ions, evolution of MX and BMXs in the drinking water distribution system, groundwater chlorination and infiltration of water coming from chlorination processes in groundwater).

  17. Analysis of Flavan-3-ols and procyanidins in food samples by reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS).

    PubMed

    Rzeppa, Sebastian; Von Bargen, Christoph; Bittner, Katharina; Humpf, Hans-Ulrich

    2011-10-12

    Concentrations of the main dimeric and trimeric procyanidins (PC) and their monomeric constitutive units catechin (CT) and epicatechin (EC) were determined in food samples by using reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS). In a first step, 12 PCs (PC B1, B2, B3, B4, B5, B6, B7, B8, C1, C2, and A2 and cinnamtannin B1), of which most are not commercially available, were isolated from plant materials or synthesized and purified by a combination of column chromatographic separation techniques with different stationary phases. These PCs in combination with CT and EC were used as standard substances for identification and quantification during the following screening of food samples by RP-HPLC-ESI-MS/MS analysis. The main focus of the newly developed RP-HPLC-ESI-MS/MS method is the compensation of matrix effects by using the echo-peak technique simulating internal standard injection. The suitability of this new method was demonstrated by the determination of recovery rates being 90% or higher. Use of this method allowed the determination of patterns and concentrations of PCs in 55 food samples.

  18. Enhancing Biological Analyses with Three Dimensional Field Asymmetric Ion Mobility, Low Field Drift Time Ion Mobility and Mass Spectrometry (µFAIMS/IMS-MS) Separations

    SciTech Connect

    Zhang, Xing; Ibrahim, Yehia M.; Chen, Tsung-Chi; Kyle, Jennifer E.; Norheim, Randolph V.; Monroe, Matthew E.; Smith, Richard D.; Baker, Erin Shammel

    2015-06-30

    We report the first evaluation of a platform coupling a high speed field asymmetric ion mobility spectrometry microchip (µFAIMS) with drift tube ion mobility and mass spectrometry (IMS-MS). The µFAIMS/IMS-MS platform was used to analyze biological samples and simultaneously acquire multidimensional information of detected features from the measured FAIMS compensation fields and IMS drift times, while also obtaining accurate ion masses. These separations thereby increase the overall separation power, resulting increased information content, and provide more complete characterization of more complex samples. The separation conditions were optimized for sensitivity and resolving power by the selection of gas compositions and pressures in the FAIMS and IMS separation stages. The resulting performance provided three dimensional separations, benefitting both broad complex mixture studies and targeted analyses by e.g. improving isomeric separations and allowing detection of species obscured by “chemical noise” and other interfering peaks.

  19. Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Can Precisely Discriminate the Lineages of Listeria monocytogenes and Species of Listeria.

    PubMed

    Ojima-Kato, Teruyo; Yamamoto, Naomi; Takahashi, Hajime; Tamura, Hiroto

    2016-01-01

    The genetic lineages of Listeria monocytogenes and other species of the genus Listeria are correlated with pathogenesis in humans. Although matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a prevailing tool for rapid and reliable microbial identification, the precise discrimination of Listeria species and lineages remains a crucial issue in clinical settings and for food safety. In this study, we constructed an accurate and reliable MS database to discriminate the lineages of L. monocytogenes and the species of Listeria (L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, L. ivanovii, L. grayi, and L. rocourtiae) based on the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum (S10-GERMS) proteotyping method, which relies on both genetic information (genomics) and observed MS peaks in MALDI-TOF MS (proteomics). The specific set of eight biomarkers (ribosomal proteins L24, L6, L18, L15, S11, S9, L31 type B, and S16) yielded characteristic MS patterns for the lineages of L. monocytogenes and the different species of Listeria, and led to the construction of a MS database that was successful in discriminating between these organisms in MALDI-TOF MS fingerprinting analysis followed by advanced proteotyping software Strain Solution analysis. We also confirmed the constructed database on the proteotyping software Strain Solution by using 23 Listeria strains collected from natural sources.

  20. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass-Spectrometry (MALDI-TOF MS) Based Microbial Identifications: Challenges and Scopes for Microbial Ecologists

    PubMed Central

    Rahi, Praveen; Prakash, Om; Shouche, Yogesh S.

    2016-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) based biotyping is an emerging technique for high-throughput and rapid microbial identification. Due to its relatively higher accuracy, comprehensive database of clinically important microorganisms and low-cost compared to other microbial identification methods, MALDI-TOF MS has started replacing existing practices prevalent in clinical diagnosis. However, applicability of MALDI-TOF MS in the area of microbial ecology research is still limited mainly due to the lack of data on non-clinical microorganisms. Intense research activities on cultivation of microbial diversity by conventional as well as by innovative and high-throughput methods has substantially increased the number of microbial species known today. This important area of research is in urgent need of rapid and reliable method(s) for characterization and de-replication of microorganisms from various ecosystems. MALDI-TOF MS based characterization, in our opinion, appears to be the most suitable technique for such studies. Reliability of MALDI-TOF MS based identification method depends mainly on accuracy and width of reference databases, which need continuous expansion and improvement. In this review, we propose a common strategy to generate MALDI-TOF MS spectral database and advocated its sharing, and also discuss the role of MALDI-TOF MS based high-throughput microbial identification in microbial ecology studies.

  1. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass-Spectrometry (MALDI-TOF MS) Based Microbial Identifications: Challenges and Scopes for Microbial Ecologists.

    PubMed

    Rahi, Praveen; Prakash, Om; Shouche, Yogesh S

    2016-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) based biotyping is an emerging technique for high-throughput and rapid microbial identification. Due to its relatively higher accuracy, comprehensive database of clinically important microorganisms and low-cost compared to other microbial identification methods, MALDI-TOF MS has started replacing existing practices prevalent in clinical diagnosis. However, applicability of MALDI-TOF MS in the area of microbial ecology research is still limited mainly due to the lack of data on non-clinical microorganisms. Intense research activities on cultivation of microbial diversity by conventional as well as by innovative and high-throughput methods has substantially increased the number of microbial species known today. This important area of research is in urgent need of rapid and reliable method(s) for characterization and de-replication of microorganisms from various ecosystems. MALDI-TOF MS based characterization, in our opinion, appears to be the most suitable technique for such studies. Reliability of MALDI-TOF MS based identification method depends mainly on accuracy and width of reference databases, which need continuous expansion and improvement. In this review, we propose a common strategy to generate MALDI-TOF MS spectral database and advocated its sharing, and also discuss the role of MALDI-TOF MS based high-throughput microbial identification in microbial ecology studies. PMID:27625644

  2. Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Can Precisely Discriminate the Lineages of Listeria monocytogenes and Species of Listeria

    PubMed Central

    Yamamoto, Naomi; Takahashi, Hajime; Tamura, Hiroto

    2016-01-01

    The genetic lineages of Listeria monocytogenes and other species of the genus Listeria are correlated with pathogenesis in humans. Although matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a prevailing tool for rapid and reliable microbial identification, the precise discrimination of Listeria species and lineages remains a crucial issue in clinical settings and for food safety. In this study, we constructed an accurate and reliable MS database to discriminate the lineages of L. monocytogenes and the species of Listeria (L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, L. ivanovii, L. grayi, and L. rocourtiae) based on the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum (S10-GERMS) proteotyping method, which relies on both genetic information (genomics) and observed MS peaks in MALDI-TOF MS (proteomics). The specific set of eight biomarkers (ribosomal proteins L24, L6, L18, L15, S11, S9, L31 type B, and S16) yielded characteristic MS patterns for the lineages of L. monocytogenes and the different species of Listeria, and led to the construction of a MS database that was successful in discriminating between these organisms in MALDI-TOF MS fingerprinting analysis followed by advanced proteotyping software Strain Solution analysis. We also confirmed the constructed database on the proteotyping software Strain Solution by using 23 Listeria strains collected from natural sources. PMID:27442502

  3. Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Can Precisely Discriminate the Lineages of Listeria monocytogenes and Species of Listeria.

    PubMed

    Ojima-Kato, Teruyo; Yamamoto, Naomi; Takahashi, Hajime; Tamura, Hiroto

    2016-01-01

    The genetic lineages of Listeria monocytogenes and other species of the genus Listeria are correlated with pathogenesis in humans. Although matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a prevailing tool for rapid and reliable microbial identification, the precise discrimination of Listeria species and lineages remains a crucial issue in clinical settings and for food safety. In this study, we constructed an accurate and reliable MS database to discriminate the lineages of L. monocytogenes and the species of Listeria (L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, L. ivanovii, L. grayi, and L. rocourtiae) based on the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum (S10-GERMS) proteotyping method, which relies on both genetic information (genomics) and observed MS peaks in MALDI-TOF MS (proteomics). The specific set of eight biomarkers (ribosomal proteins L24, L6, L18, L15, S11, S9, L31 type B, and S16) yielded characteristic MS patterns for the lineages of L. monocytogenes and the different species of Listeria, and led to the construction of a MS database that was successful in discriminating between these organisms in MALDI-TOF MS fingerprinting analysis followed by advanced proteotyping software Strain Solution analysis. We also confirmed the constructed database on the proteotyping software Strain Solution by using 23 Listeria strains collected from natural sources. PMID:27442502

  4. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass-Spectrometry (MALDI-TOF MS) Based Microbial Identifications: Challenges and Scopes for Microbial Ecologists

    PubMed Central

    Rahi, Praveen; Prakash, Om; Shouche, Yogesh S.

    2016-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) based biotyping is an emerging technique for high-throughput and rapid microbial identification. Due to its relatively higher accuracy, comprehensive database of clinically important microorganisms and low-cost compared to other microbial identification methods, MALDI-TOF MS has started replacing existing practices prevalent in clinical diagnosis. However, applicability of MALDI-TOF MS in the area of microbial ecology research is still limited mainly due to the lack of data on non-clinical microorganisms. Intense research activities on cultivation of microbial diversity by conventional as well as by innovative and high-throughput methods has substantially increased the number of microbial species known today. This important area of research is in urgent need of rapid and reliable method(s) for characterization and de-replication of microorganisms from various ecosystems. MALDI-TOF MS based characterization, in our opinion, appears to be the most suitable technique for such studies. Reliability of MALDI-TOF MS based identification method depends mainly on accuracy and width of reference databases, which need continuous expansion and improvement. In this review, we propose a common strategy to generate MALDI-TOF MS spectral database and advocated its sharing, and also discuss the role of MALDI-TOF MS based high-throughput microbial identification in microbial ecology studies. PMID:27625644

  5. Spray Inlet Proton Transfer Reaction Mass Spectrometry (SI-PTR-MS) for Rapid and Sensitive Online Monitoring of Benzene in Water.

    PubMed

    Zou, Xue; Kang, Meng; Li, Aiyue; Shen, Chengyin; Chu, Yannan

    2016-03-15

    Rapid and sensitive monitoring of benzene in water is very important to the health of people and for environmental protection. A novel and online detection method of spray inlet proton transfer reaction mass spectrometry (SI-PTR-MS) was introduced for rapid and sensitive monitoring of trace benzene in water. A spraying extraction system was coupled with the self-developed PTR-MS. The benzene was extracted from the water sample in the spraying extraction system and continuously detected with PTR-MS. The flow of carrier gas and salt concentration in water were optimized to be 50 sccm and 20% (w/v), respectively. The response time and the limit of detection of the SI-PTR-MS for detection of benzene in water were 55 s and 0.14 μg/L at 10 s integration time, respectively. The repeatability of the SI-PTR-MS was evaluated, and the relative standard deviation of five replicate determinations was 4.3%. The SI-PTR-MS system was employed for monitoring benzene in different water matrices, such as tap water, lake water, and wastewater. The results indicated that the online SI-PTR-MS can be used for rapid and sensitive monitoring of trace benzene in water.

  6. Development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 16 'legal high' cathinone derivatives.

    PubMed

    Nic Daeid, Niamh; Savage, Kathleen A; Ramsay, Donna; Holland, Ciara; Sutcliffe, Oliver B

    2014-01-01

    The prevalence of so-called 'legal high' drugs in forensic science drug casework has increased markedly in recent years. This has given rise to both legal and analytical challenges in the identification of these substances. The requirement for validated, reliable and rapid testing methodologies for these compounds is obvious. This work reports the analysis of sixteen synthesised cathinone derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS). PMID:24438774

  7. An Assessment of the Utility of Tissue Smears in Rapid Cancer Profiling with Desorption Electrospray Ionization Mass Spectrometry (DESI-MS)

    NASA Astrophysics Data System (ADS)

    Woolman, Michael; Tata, Alessandra; Bluemke, Emma; Dara, Delaram; Ginsberg, Howard J.; Zarrine-Afsar, Arash

    2016-10-01

    Mass spectrometry imaging with desorption electrospray ionization mass spectrometry (DESI-MS) is used to characterize cancer from ex vivo slices of tissues. The process is time-consuming. The use of tissue smears for DESI-MS analysis has been proposed as it eliminates the time required to snap-freeze and section the tissue. To assess the utility of tissue smears for rapid cancer characterization, principal component analysis (PCA) was performed to evaluate the concordance between DESI-MS profiles of breast cancer from tissue slices and smears prepared on various surfaces. PCA suggested no statistical discrimination between DESI-MS profiles of tissue sections and tissue smears prepared on glass, polytetrafluoroethylene (PTFE), and porous PTFE. However, the abundances of cancer biomarker ions varied between sections and smears, with DESI-MS analysis of tissue sections yielding higher ion abundances of cancer biomarkers compared with smears. Coefficient of variance (CV) analysis suggests DESI-MS profiles from tissue smears are as reproducible as the ones from tissue sections. The limit of detection with smear samples from single pixel analysis is comparable to tissue sections that average the signal from a tissue area of 0.01 mm2. The smears prepared on the PTFE surface possessed a higher degree of homogeneity compared with the smears prepared on the glass surface. This allowed single MS scans (~1 s) from random positions across the surface of the smear to be used in rapid cancer typing with good reproducibility, providing pathologic information for cancer typing at speeds suitable for clinical utility.

  8. Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    PubMed

    Molinelli, Alejandro R; Rose, Charles H

    2016-01-01

    Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring.

  9. Finding a Needle in a Haystack: the Advantages of Liquid Chromatography--Tandem Mass Spectrometry (LC-MS/MS) in Determination of Sex Hormones in Children.

    PubMed

    Hirsh, Shira; Ben-Dor, Anat

    2016-06-01

    Determination of steroid sex hormones concentrations in children is very important for diagnosis of a wide range of pubertal, adrenal and sex development disorders. The majority of hormone measurements are carried out using traditional immunoassays, due to their technical simplicity, cost and availability of commercial reagents. But, due to limited specificity and sensitivity, traditional immunoassays often fail to determine low concentration analytes such as sex hormones in pediatric blood. In the last decade, the LC-MS/MS assay has risen as a new player in the analytic diagnostic field. The assay has proven appropriate for detection of very low hormones concentrations in blood, is quite easy to perform and can detect multiple steroids from a single sample. For the routine determination of an individual or panel of steroids, LC-MS/MS is now the recommended method for most diagnostic laboratories.

  10. Quantitative liquid chromatography, thermospray/tandem mass spectrometry (LC/TSP/MS/MS) analysis of some thermolabile benzodiazepines in whole-blood.

    PubMed

    Verweij, A M; Lipman, P J; Zweipfenning, P G

    1992-04-01

    An LC/TSP/MS/MS selected reaction monitoring (SRM) method in the daughter ion scan mode can be applied successfully for the quantitative determination of thermolabile benzodiazepines in whole-blood following an Extrelut extraction method. Detection limits as low as 100 pg per injection can be reached for all benzodiazepines. The benzodiazepines under investigation proved to be stable, with the exception of ketazolam for which complete degradation to diazepam was observed.

  11. Profiling intact steroid sulfates and unconjugated steroids in biological fluids by liquid chromatography-tandem mass spectrometry (LC-MS-MS).

    PubMed

    Galuska, Christina E; Hartmann, Michaela F; Sánchez-Guijo, Alberto; Bakhaus, Katharina; Geyer, Joachim; Schuler, Gerhard; Zimmer, Klaus-Peter; Wudy, Stefan A

    2013-07-01

    Within the combined DFG research project "Sulfated Steroids in Reproduction" an analytical method was needed for determining sulfated and unconjugated steroids with highest specificity out of different biological matrices such as aqueous solution, cell lysate and serum. With regard to this analytical challenge, LC-MS-MS presents the technique of choice because it permits (1) analysis of the intact steroid conjugate, (2) allows for simultaneous determination of multiple analytes (profiling, targeted metabolomics approach) and (3) is independent of phenomena such as cross-reactivity. Sample work up consisted of incubation of sample with internal standards (deuterium labeled steroids) followed by solid phase extraction. Only serum samples required a protein precipitation step prior to solid phase extraction. The extract was divided in two parts: six steroid sulfates (E1S, E2S, AS, 16-OH-DHEAS, PREGS, DHEAS) were analyzed by C18aQ-ESI-MS-MS in negative ion mode and eleven unconjugated steroids (E3, 16-OH-DHEA, E1, E2, (4)A, DHEA, T, 17-OH-PREG, Prog, An, PREG) were analyzed by C18-APCI-MS-MS in positive ion mode. For steroid sulfates, we found high sensitivities with LoQ values ranging from 0.08 to 1 ng mL(-1). Unconjugated steroids showed LoQ values between 0.5 and 10 ng mL(-1). Calibration plots showed excellent linearity. Mean intra- and inter-assay CVs were 2.4% for steroid sulfates and 6.4% for unconjugated steroids. Accuracy - determined in a two-level spike experiment - showed mean relative errors of 5.9% for steroid sulfates and 6.1% for unconjugated steroids. In summary, we describe a novel LC-MS-MS procedure capable of profiling six steroid sulfates and eleven unconjugated steroids from various biological matrices.

  12. Analytical mass spectrometry of poly(ethylene glycol) additives in artists' acrylic emulsion media, artists' paints, and microsamples from acrylic paintings using MALDI-MS and nanospray-ESI-MS

    NASA Astrophysics Data System (ADS)

    Hoogland, F. G.; Boon, J. J.

    2009-07-01

    Poly(ethylene glycol) (PEG) compounds in artists' acrylic emulsion paint products from different paint manufacturers, ranging from base emulsions (Rohm and Haas, Röhm and Scott Bader), to modified emulsions and complete paints (Rowney, Winsor and Newton, Golden, Liquitex, Lascaux), were characterised with a newly developed mass spectrometric method which combines data from Matrix assisted laser desorption/ionisation mass spectrometry (MALDI-MS) and nano-electrospray ionisation mass spectrometry (nano-ESI-MS(MS)). MALDI-MS was used for the determination of the molar mass distribution (MMD) and calculation of the molar mass averages (Mw and Mn), the polydispersity index (D) and the relative amount of a specific distribution if multiple PEGs were present. Electrospray ionisation mass spectrometry was used for the end-group analysis. Three different classes of polymers was found being PEG, polypropylene glycol (PPG) and a block copolymer of polyethylene glycol/polypropylene glycol (PEG/PPG) with molar mass averages ranging from 400 to 4200 Da. PEG compounds with a nonylphenyl or an octylphenyl hydrophobic end-group are most common. The hydrophilic end-groups observed are hydroxide and/or sulphate. Water extracts of microsamples from a palette by David Hockney dating from 1970 and samples paintings by Patrick Caulfield (1936-2005) and John Hoyland (born in 1934) were investigated with the same technique. Although some artist paint manufacturers use the same specific base emulsions to make their paints, the composition of the PEG compounds present in the water extracts of the palette and paintings samples made it possible, in some cases, to suggest a specific brand of paint used by the artist.

  13. Simultaneous measurement of testosterone, androstenedione and dehydroepiandrosterone (DHEA) in serum and plasma using Isotope-Dilution 2-Dimension Ultra High Performance Liquid-Chromatography Tandem Mass Spectrometry (ID-LC-MS/MS).

    PubMed

    Büttler, Rahel M; Martens, Frans; Kushnir, Mark M; Ackermans, Mariette T; Blankenstein, Marinus A; Heijboer, Annemieke C

    2015-01-01

    The adrenal and gonadal androgens, testosterone, androstenedione and dehydroepiandrosterone (DHEA) play an important role in sexual development as well as in other processes. We developed a method for simultaneous quantitative analysis of serum and plasma testosterone, androstenedione and DHEA levels using Isotope-Dilution Liquid-Chromatography Tandem Mass Spectrometry (ID-LC-MS/MS). Samples underwent liquid-liquid extraction and were analyzed on an Acquity 2D-UPLC-System and a Xevo TQ-S tandem mass spectrometer (Waters). The intra-assay and inter-assay coefficients of variation were <4.0%, <6.3% and <7.0% and <6.0%, <8.1% and <7.7% for testosterone, androstenedione and DHEA, respectively. Inter-assay CVs at the lower limit were 10.6%, 16.9% and 9.0% for testosterone (0.10nmol/L), androstenedione (0.10nmol/L) and DHEA (1.0nmol/L), respectively. Recoveries of spiked analytes were 93-107%. The present testosterone method compared well (y=1.00x-0.04; r=0.998) to a published ID-LC-MS/MS method for testosterone in our lab. The latter method being concordant with a published reference method (Bui et al., 2013). The present method compared well to a published ID-LC-MS/MS method (Kushnir et al., 2010) (y=1.06x-0.06; r=0.996 for testosterone; y=1.04x-0.04; r=0.995 for androstenedione and y=1.03x+0.01; r=0.991 for DHEA). In conclusion, we developed a sensitive and accurate ID-LC-MS/MS method to simultaneously measure serum testosterone, androstenedione and DHEA in serum and plasma.

  14. Inborn Error of Metabolism (IEM) screening in Singapore by electrospray ionization-tandem mass spectrometry (ESI/MS/MS): An 8 year journey from pilot to current program.

    PubMed

    Lim, J S; Tan, E S; John, C M; Poh, S; Yeo, S J; Ang, J S M; Adakalaisamy, P; Rozalli, R A; Hart, C; Tan, E T H; Ranieri, E; Rajadurai, V S; Cleary, M A; Goh, D L M

    2014-01-01

    IEM screening by ESI/MS/MS was introduced in Singapore in 2006. There were two phases; a pilot study followed by implementation of the current program. The pilot study was over a 4 year period. During the pilot study, a total of 61,313 newborns were screened, and 20 cases of IEM were diagnosed (detection rate of 1:3065; positive predictive value (PPV) of 11%). Regular self-review, participation in external quality assessment and the Region 4 Genetic collaborative programs (http://www.region4genetics.org/) had led to the robust development of our current NBS MS/MS program. Overall, from July 2006 to April 2014, we screened a total of 177,267 newborns. The mean age at the time of sampling was 47.9h. Transportation of samples to the testing laboratory averaged 0.92 day. Upon receipt of sample, the NBS result was available within 1.64 days and within 3.8 days if a second tier test was required. Using absolute cut-off values in place of the initial 99th percentile reference range for the analyte markers and the introduction of two 2nd tier tests (MMA and Succinylacetone) had significantly reduced the high recall rate from an initial 1.5% during the period 2006-07 to 0.12% in 2013. The NBS MS/MS program was supported by a centralized confirmatory/diagnostic testing laboratory and a rapid response team of metabolic specialists. The detection rate was 1: 3165 (1:2727 if maternal conditions were also included). There were 23 newborns affected with organic acidemias (incidence: 1:6565), 23 with fatty acid oxidation disorders (incidence: 1:6565), and 10 with amino acidopathies (incidence 1:17,726). The performance metrics for the screening test were acceptable (sensitivity: 95.59%, specificity: 99.85%, PPV: 20%, FPR: 0.15). Participation in the NBS MS/MS program by hospitals was voluntary, and in 2013, the uptake rate was 71% of the annual births. We hope that newborn screening by MS/MS will become a standard of care for all babies in Singapore.

  15. Identification of Enterobacteriaceae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the VITEK MS system.

    PubMed

    Richter, S S; Sercia, L; Branda, J A; Burnham, C-A D; Bythrow, M; Ferraro, M J; Garner, O B; Ginocchio, C C; Jennemann, R; Lewinski, M A; Manji, R; Mochon, A B; Rychert, J A; Westblade, L F; Procop, G W

    2013-12-01

    This multicenter study evaluated the accuracy of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry identifications from the VITEK MS system (bioMérieux, Marcy l'Etoile, France) for Enterobacteriaceae typically encountered in the clinical laboratory. Enterobacteriaceae isolates (n = 965) representing 17 genera and 40 species were analyzed on the VITEK MS system (database v2.0), in accordance with the manufacturer's instructions. Colony growth (≤72 h) was applied directly to the target slide. Matrix solution (α-cyano-4-hydroxycinnamic acid) was added and allowed to dry before mass spectrometry analysis. On the basis of the confidence level, the VITEK MS system provided a species, genus only, or no identification for each isolate. The accuracy of the mass spectrometric identification was compared to 16S rRNA gene sequencing performed at MIDI Labs (Newark, DE). Supplemental phenotypic testing was performed at bioMérieux when necessary. The VITEK MS result agreed with the reference method identification for 96.7% of the 965 isolates tested, with 83.8% correct to the species level and 12.8% limited to a genus-level identification. There was no identification for 1.7% of the isolates. The VITEK MS system misidentified 7 isolates (0.7 %) as different genera. Three Pantoea agglomerans isolates were misidentified as Enterobacter spp. and single isolates of Enterobacter cancerogenus, Escherichia hermannii, Hafnia alvei, and Raoultella ornithinolytica were misidentified as Klebsiella oxytoca, Citrobacter koseri, Obesumbacterium proteus, and Enterobacter aerogenes, respectively. Eight isolates (0.8 %) were misidentified as a different species in the correct genus. The VITEK MS system provides reliable mass spectrometric identifications for Enterobacteriaceae. PMID:23818163

  16. Quantitation of Flecainide, Mexiletine, Propafenone, and Amiodarone in Serum or Plasma Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Slawson, Matthew H; Johnson-Davis, Kamisha L

    2016-01-01

    Flecainide, mexiletine, propafenone, and amiodarone are antiarrhythmic drugs that are used primarily in the treatment of cardiac arrhythmias. The monitoring of the use of these drugs has applications in therapeutic drug monitoring and overdose situations. LC-MS/MS is used to analyze plasma/serum extracts with loxapine as the internal standard to ensure accurate quantitation and control for any potential matrix effects. Positive ion electrospray is used to introduce the analytes into the mass spectrometer. Selected reaction monitoring of two product ions for each analyte allows for the calculation of ion ratios which ensures correct identification of each analyte, while a matrix matched calibration curve is used for quantitation. PMID:26660169

  17. Comparison of the Microflex LT and Vitek MS Systems for Routine Identification of Bacteria by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

    PubMed Central

    Busson, Laurent; Wybo, Ingrid; El Haj, Rachid Ait; Dediste, Anne; Vandenberg, Olivier

    2012-01-01

    This study compared the performance of three matrix-assisted laser desorption ionization–time of flight mass spectrometry systems: Microflex LT (Bruker Daltonics, Bremen, Germany), Vitek MS RUO (Axima Assurance-Saramis database; bioMérieux, Marcy l'Etoile, France), and Vitek MS IVD (bioMérieux). A total of 1,129 isolates, including 1,003 routine isolates, 73 anaerobes, and 53 bacterial enteropathogens, were tested on the Microflex LT and Axima Assurance devices. The spectra were analyzed using three databases: Biotyper (Bruker Daltonics), Saramis, and Vitek MS (bioMérieux). Among the routine isolates requiring identification to the species level (n = 986), 92.7% and 93.2% were correctly identified by the Biotyper and Vitek MS databases, respectively. The Vitek MS database is more specific for the identification of Streptococcus viridans. For the anaerobes, the Biotyper database often identified Fusobacterium isolates to only the genus level, which is of low clinical significance, whereas 20% of the Bacteroides species were not identified or were misidentified by the Vitek MS database. For the enteropathogens, the poor discrimination between Escherichia coli and Shigella explains the high proportion of unidentified organisms. In contrast to the Biotyper database, the Vitek MS database properly discriminated all of the Salmonella entrica serovar Typhi isolates (n = 5). The performance of the Saramis database was globally poorer. In conclusion, for routine procedures, the Microflex LT and Vitek-MS systems are equally good choices in terms of analytical efficiency. Other factors, including price, work flow, and lab activity, will affect the choice of a system. PMID:22322345

  18. Proteomic analysis of rat plasma with experimental autoimmune uveitis based on label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Guo, Dadong; Gu, Peiming; Liu, Zhengfeng; Tang, Kai; Du, Yuxiang; Bi, Hongsheng

    2015-01-22

    Uveitis is a severe autoimmune eye disease that can cause intraocular inflammation even lead to severe vision loss, and the occurrence of uveitis can be closely associated with abnormal expression of proteins. However, the abnormally expressed proteins involved in uveitis are not well identified. Using liquid chromatography-tandem mass spectrometry technique, we examined the alterations in proteomic expression profiling in rat plasma specimens related to experimental autoimmune uveitis (EAU) versus normal samples. In addition, the experimental verification was further performed using enzyme-linked immunosorbent assay (ELISA) for abnormally expressed proteins in EAU rat plasma. The results indicate that 62 proteins were upregulated and 106 proteins were downregulated in plasma from EAU rats compared with those in saline-treated samples. In the meantime, we observed that the plasma level of complement component 3 in EAU rats was upregulated versus saline-treated rats (from 92.32μg/mL to 168.92μg/mL), whereas the level of interleukin-1 receptor accessory protein was downregulated (from 1120.97pg/mL to 798.39pg/mL), and these results were highly in agreement with those of mass spectrometry determination. Taken together, our results indicate that liquid chromatography-tandem mass spectrometry analysis possesses a good resolution for peptides in plasma, and the findings will provide the baseline plasma dataset for EAU rats and the relevant information can contribute to future studies on the understanding the mechanism of uveitis.

  19. Determination of mercury in fish otoliths by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS)†

    PubMed Central

    Kenduzler, Erdal; Ates, Mehmet; Arslan, Zikri; McHenry, Melanie; Tchounwou, Paul B.

    2012-01-01

    A method based on cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS) has been developed for determination of inorganic mercury, Hg(II), and total mercury in fish otoliths. Sodium borohydride (NaBH4) was used as the only reducing agent and its concentration was optimized across an acidity gradient to selectively reduce Hg(II) without affecting methylmercury, CH3Hg(I). Inorganic Hg was quantitatively reduced to elemental mercury (Hg0) with 1×10−4% (m/v) NaBH4. CH3Hg(I) required a minimum of 0.5% (m/v) NaBH4 for complete reduction. Increasing the HCl concentration of solution to 5% (v/v) improved the selectivity toward Hg(II) as it decreased the signals from CH3Hg(I) to baseline levels. Potassium ferricyanide solution was the most effective in eliminating the memory effects of Hg compared with a number of chelating and oxidizing agents, including EDTA, gold chloride, thiourea, cerium ammonium nitrate and 2-mercaptoethylamine chloride. The relative standard deviation (RSD) was less than 5% for 1.0 μg L−1 Hg(II) solution. The detection limits were 4.2 and 6.4 ng L−1 (ppt) for Hg(II) and total Hg, respectively. Sample dissolution conditions and recoveries were examined with ultra-pure CaCO3 (99.99%) spiked with Hg(II) and CH3HgCl. Methylmercury was stable when dissolution was performed with up to 20% (v/v) HCl at 100 oC. Recoveries from spiked solutions were higher than 95% for both Hg(II) and CH3Hg(I). The method was applied to the determination of Hg(II) and total Hg concentrations in the otoliths of red emperor (CRM 22) and Pacific halibut. Total Hg concentration in the otoliths was 0.038 ± 0.004 μg g−1 for the red emperor and 0.021 ± 0.003 μg g−1 for the Pacific halibut. Inorganic Hg accounted for about 25% of total Hg indicating that Hg in the otoliths was predominantly organic mercury (e.g., methylmercury). However, as opposed to the bioaccumulation in tissues, methylmercury levels in otoliths was very low suggesting a

  20. Comprehensive multidimensional separation methods by hyphenation of single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) with GC and GCxGC.

    PubMed

    Eschner, Markus S; Welthagen, Werner; Gröger, Thomas M; Gonin, Marc; Fuhrer, Katrin; Zimmermann, Ralf

    2010-10-01

    One- and comprehensive two-dimensional gas chromatography were hyphenated with soft photoionization mass spectrometry. The characteristics of these two- and three-dimensional comprehensive separation techniques are discussed in detail. Using the innovative electron beam pumped excimer light source (EBEL) for single-photon ionization (SPI), organic molecules with ionization energies (E ( i )) of below 9.8 eV can be detected by a time-of-flight mass spectrometer (TOF-MS). SPI with 126 nm vacuum ultraviolet (VUV) photons enables the universal and soft ionization of organic molecules. SPI-TOF-MS hyphenated to one-dimensional gas chromatography results in a comprehensive two-dimensional separation method (GCxMS). To demonstrate this, diesel fuel was analyzed, and the resulting GCxMS chromatograms are discussed in depth. A three-dimensional separation method was also realized by combining comprehensive two-dimensional gas chromatography (GCxGC) with SPI-MS. In the resulting separation space, constituents originating from mineral oil diesel blended with biodiesel were dispersed along the two GC separation axes, while the molecular mass axis served as a third separation dimension.

  1. Rapid and facile detection of four date rape drugs in different beverages utilizing proton transfer reaction mass spectrometry (PTR-MS).

    PubMed

    Jürschik, Simone; Agarwal, Bishu; Kassebacher, Thomas; Sulzer, Philipp; Mayhew, Christopher A; Märk, Tilmann D

    2012-09-01

    In this work, we illustrate the application of proton transfer reaction mass spectrometry (PTR-MS) in the field of food and drink safety. We present proof-of-principle measurements of four different drinks (water, tea, red wine and white wine) each spiked separately with four different date rape drugs (chloral hydrate, tricholorethanol, γ-butyrolactone and butanediol). At first, the ideal PTR-MS operating conditions (reduced electric field strength and monitoring the most abundant [fragment] ion) for detection of the drugs were determined utilizing a time-of-flight-based PTR-MS instrument. We then dissolved small quantities of the drugs (below the activation threshold for effects on humans) into the various types of drinks and detected them using a quadrupole-based PTR-MS instrument via two different sampling methods: (1) dynamic headspace sampling and (2) direct liquid injection. Both methods have their advantages and drawbacks. Only with dynamic headspace sampling can rape drug contaminations be detected within a timeframe of seconds, and therefore, this method is the most promising use of PTR-MS as a fast, sensitive and selective monitor for the detection of food and drink contamination. PMID:22972776

  2. Performances and Reliability of Bruker Microflex LT and VITEK MS MALDI-TOF Mass Spectrometry Systems for the Identification of Clinical Microorganisms.

    PubMed

    Bilecen, Kivanc; Yaman, Gorkem; Ciftci, Ugur; Laleli, Yahya Rauf

    2015-01-01

    In clinical microbiology laboratories, routine microbial identification is mostly performed using culture based methodologies requiring 24 to 72 hours from culturing to identification. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology has been established as a cost effective, reliable, and faster alternative identification platform. In this study, we evaluated the reliability of the two available MALDI-TOF MS systems for their routine clinical level identification accuracy and efficiency in a clinical microbiology laboratory setting. A total of 1,341 routine phenotypically identified clinical bacterial and fungal isolates were selected and simultaneously analyzed using VITEK MS (bioMérieux, France) and Microflex LT (Bruker Diagnostics, Germany) MALDI-TOF MS systems. For any isolate that could not be identified with either of the systems and for any discordant result, 16S rDNA gene or ITS1/ITS2 sequencing was used. VITEK MS and Microflex LT correctly identified 1,303 (97.17%) and 1,298 (96.79%) isolates to the species level, respectively. In 114 (8.50%) isolates initial phenotypic identification was inaccurate. Both systems showed a similar identification efficiency and workflow robustness, and they were twice as more accurate compared to routine phenotypic identification in our sample pool. MALDITOF systems with their accuracy and robustness offer a good identification platform for routine clinical microbiology laboratories.

  3. Performances and Reliability of Bruker Microflex LT and VITEK MS MALDI-TOF Mass Spectrometry Systems for the Identification of Clinical Microorganisms

    PubMed Central

    Yaman, Gorkem; Ciftci, Ugur; Laleli, Yahya Rauf

    2015-01-01

    In clinical microbiology laboratories, routine microbial identification is mostly performed using culture based methodologies requiring 24 to 72 hours from culturing to identification. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology has been established as a cost effective, reliable, and faster alternative identification platform. In this study, we evaluated the reliability of the two available MALDI-TOF MS systems for their routine clinical level identification accuracy and efficiency in a clinical microbiology laboratory setting. A total of 1,341 routine phenotypically identified clinical bacterial and fungal isolates were selected and simultaneously analyzed using VITEK MS (bioMérieux, France) and Microflex LT (Bruker Diagnostics, Germany) MALDI-TOF MS systems. For any isolate that could not be identified with either of the systems and for any discordant result, 16S rDNA gene or ITS1/ITS2 sequencing was used. VITEK MS and Microflex LT correctly identified 1,303 (97.17%) and 1,298 (96.79%) isolates to the species level, respectively. In 114 (8.50%) isolates initial phenotypic identification was inaccurate. Both systems showed a similar identification efficiency and workflow robustness, and they were twice as more accurate compared to routine phenotypic identification in our sample pool. MALDITOF systems with their accuracy and robustness offer a good identification platform for routine clinical microbiology laboratories. PMID:26793718

  4. A 96-well single-pot protein precipitation, liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of muraglitazar, a novel diabetes drug, in human plasma.

    PubMed

    Xue, Y-J; Liu, Jane; Pursley, Janice; Unger, Steve

    2006-02-01

    A 96-well single-pot protein precipitation, liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of muraglitazar, a PPAR alpha/gamma dual agonist, in human plasma. The internal standard, a chemical analogue, was dissolved in acetonitrile containing 0.1% formic acid. The solvent system was also served as a protein precipitation reagent. Human plasma samples (0.1 mL) and the internal standard solution (0.3 mL) were added to a 96-well plate. The plate was vortexed for 1 min and centrifuged for 5 min. Then the supernatant layers were directly injected into the LC/MS/MS system. The chromatographic separation was achieved isocratically on a Phenomenox C18(2) Luna column (2 mm x 50 mm, 5 microm). The mobile phase contained 20/80 (v/v) of water and acetonitrile containing 0.1% formic acid. Detection was by positive ion electrospray tandem mass spectrometry on a Sciex API 3000. The standard curve, which ranged from 1 to 1000 ng/mL, was fitted to a 1/x weighted quadratic regression model. This single-pot approach effectively eliminated three time consuming sample preparation steps: sample transfer, dry-down, and reconstitution before the injection, while it preserved all the benefits of the traditional protein precipitation. By properly adjusting the autosampler needle offset level, only the supernatant was injected, without disturbing the precipitated proteins in the bottom. As a result, the quality of chromatography and column life were not compromised. After more than 600 injections, there was only slightly increase of column back-pressure. The validation results demonstrated that this method was rugged and provide satisfactory precision and accuracy. The method has been successfully applied to analyze human plasma samples in support of a first-in-man study. This method has also been validated in monkey and mouse plasma for the determination of muraglitazar. PMID:16388995

  5. Analysis of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues in chlorine-treated water by gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS).

    PubMed

    Planas, Carles; Ventura, Francesc; Caixach, Josep; Martín, Jordi; Boleda, M Rosa; Paraira, Miquel

    2015-11-01

    A simple, selective and sensitive method for the analysis of the strong mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues (BMXs) in chlorine-treated water has been developed. The method is based on gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS), previous liquid-liquid extraction (LLE) of a smaller sample volume compared to other methods and on-line derivatization with a silylation reactive. GC-QqQ-MS/MS has been raised as an alternative easier to perform than gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) for the analysis of MX and BMXs, and it allows to achieve low LODs (0.3 ng/L for MX and 0.4-0.9 ng/L for BMXs). This technique had not been previously described for the analysis of MX and BMXs. Quality parameters were calculated and real samples related to 3 drinking water treatment plants (DWTPs), tap water and both untreated and chlorinated groundwater were analyzed. Concentrations of 0.3-6.6 ng/L for MX and 1.0-7.3 ng/L for BMXs were detected. Results were discussed according to five of the main factors affecting MX and BMXs formation in chlorine-treated water (organic precursors, influence of bromide ions, evolution of MX and BMXs in the drinking water distribution system, groundwater chlorination and infiltration of water coming from chlorination processes in groundwater). PMID:26452804

  6. Stability considerations of aspartame in the direct analysis of artificial sweeteners in water samples using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

    PubMed

    Berset, Jean-Daniel; Ochsenbein, Nicole

    2012-07-01

    A HPLC-MS/MS method is presented for the simultaneous determination of frequently used artificial sweeteners (ASs) and the main metabolite of aspartame (ASP), diketopiperazine (DKP), in environmental water samples using the direct-injection (DI) technique, thereby achieving limits of quantification (LOQ) of 10 ng L(-1). For a reliable quantification of ASP pH should be adjusted to 4.3 to prevent formation of the metabolite. Acesulfame (ACE), saccharin (SAC), cyclamate (CYC) and sucralose (SUC) were ubiquitously found in water samples. Highest concentrations up to 61 μg L(-1) of ACE were found in wastewater effluents, followed by surface water with concentrations up to 7 μg L(-1), lakes up to 600 ng L(-1) and groundwater and tap water up to 70 ng L(-1). The metabolite DKP was only detected in wastewater up to 200 ng L(-1) and at low detection frequencies.

  7. Rapid Characterization of Microalgae and Microalgae Mixtures Using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS).

    PubMed

    Barbano, Duane; Diaz, Regina; Zhang, Lin; Sandrin, Todd; Gerken, Henri; Dempster, Thomas

    2015-01-01

    Current molecular methods to characterize microalgae are time-intensive and expensive. Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) may represent a rapid and economical alternative approach. The objectives of this study were to determine whether MALDI-TOF MS can be used to: 1) differentiate microalgae at the species and strain levels and 2) characterize simple microalgal mixtures. A common protein extraction sample preparation method was used to facilitate rapid mass spectrometry-based analysis of 31 microalgae. Each yielded spectra containing between 6 and 56 peaks in the m/z 2,000 to 20,000 range. The taxonomic resolution of this approach appeared higher than that of 18S rDNA sequence analysis. For example, two strains of Scenedesmus acutus differed only by two 18S rDNA nucleotides, but yielded distinct MALDI-TOF mass spectra. Mixtures of two and three microalgae yielded relatively complex spectra that contained peaks associated with members of each mixture. Interestingly, though, mixture-specific peaks were observed at m/z 11,048 and 11,230. Our results suggest that MALDI-TOF MS affords rapid characterization of individual microalgae and simple microalgal mixtures.

  8. Rapid Characterization of Microalgae and Microalgae Mixtures Using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS)

    PubMed Central

    Barbano, Duane; Diaz, Regina; Zhang, Lin; Sandrin, Todd; Gerken, Henri; Dempster, Thomas

    2015-01-01

    Current molecular methods to characterize microalgae are time-intensive and expensive. Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) may represent a rapid and economical alternative approach. The objectives of this study were to determine whether MALDI-TOF MS can be used to: 1) differentiate microalgae at the species and strain levels and 2) characterize simple microalgal mixtures. A common protein extraction sample preparation method was used to facilitate rapid mass spectrometry-based analysis of 31 microalgae. Each yielded spectra containing between 6 and 56 peaks in the m/z 2,000 to 20,000 range. The taxonomic resolution of this approach appeared higher than that of 18S rDNA sequence analysis. For example, two strains of Scenedesmus acutus differed only by two 18S rDNA nucleotides, but yielded distinct MALDI-TOF mass spectra. Mixtures of two and three microalgae yielded relatively complex spectra that contained peaks associated with members of each mixture. Interestingly, though, mixture-specific peaks were observed at m/z 11,048 and 11,230. Our results suggest that MALDI-TOF MS affords rapid characterization of individual microalgae and simple microalgal mixtures. PMID:26271045

  9. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS). Final progress report, December 1, 1989--December 31, 1992

    SciTech Connect

    Browner, R.F.

    1992-12-01

    One of the most dramatic developments in mass spectrometry in the last fifteen years has been the evolution of versatile and powerful interfacing approaches that allow direct chromatographic coupling of separations techniques to mass spectrometers. The most successful of these approaches have been aerosol-based. This report describes the research carried out under DOE support directed toward fundamental studies with the Particle Beam LC/MS interface (also known as the MAGIC LC/MS interface). The primary goal has been to gain a better understanding of aerosol generation, transport, vaporization, and ionization processes which forms the basis of the technique. Gaining a deeper understanding of the basic physical processes on which particle Beam LC/MS is based provides the most direct way to improve performance benchmarks, such as (1) detection limits (2) quality of mass spectra (3) range of compound types possible, and (4) the ability to interface with all types of separation techniques. This research effort has been devoted to developing a fundamental understanding of the basic physical process which underlie aerosol mass spectrometry interfacing approaches. The paper describes chromatographic peak broadening studies and carrier effects with the particle beam interface.

  10. IMS - MS Data Extractor

    SciTech Connect

    2015-10-20

    An automated drift time extraction and computed associated collision cross section software tool for small molecule analysis with ion mobility spectrometry-mass spectrometry (IMS-MS). The software automatically extracts drift times and computes associated collision cross sections for small molecules analyzed using ion mobility spectrometry-mass spectrometry (IMS-MS) based on a target list of expected ions provided by the user.

  11. Deconstruction of Activity-Dependent Covalent Modification of Heme in Human Neutrophil Myeloperoxidase by Multistage Mass Spectrometry (MS[superscript 4])

    SciTech Connect

    Geoghegan, Kieran F.; Varghese, Alison H.; Feng, Xidong; Bessire, Andrew J.; Conboy, James J.; Ruggeri, Roger B.; Ahn, Kay; Spath, Samantha N.; Filippov, Sergey V.; Conrad, Steven J.; Carpino, Philip A.; Guimarães, Cristiano R.W.; Vajdos, Felix F.

    2013-03-07

    Myeloperoxidase (MPO) is known to be inactivated and covalently modified by treatment with hydrogen peroxide and agents similar to 3-(2-ethoxypropyl)-2-thioxo-2,3-dihydro-1H-purin-6(9H)-one (1), a 254.08 Da derivative of 2-thioxanthine. Peptide mapping by liquid chromatography and mass spectrometry detected modification by 1 in a labile peptide-heme-peptide fragment of the enzyme, accompanied by a mass increase of 252.08 Da. The loss of two hydrogen atoms was consistent with mechanism-based oxidative coupling. Multistage mass spectrometry (MS{sup 4}) of the modified fragment in an ion trap/Orbitrap spectrometer demonstrated that 1 was coupled directly to heme. Use of a 10 amu window delivered the full isotopic envelope of each precursor ion to collision-induced dissociation, preserving definitive isotopic profiles for iron-containing fragments through successive steps of multistage mass spectrometry. Iron isotope signatures and accurate mass measurements supported the structural assignments. Crystallographic analysis confirmed linkage between the methyl substituent of the heme pyrrole D ring and the sulfur atom of 1. The final orientation of 1 perpendicular to the plane of the heme ring suggested a mechanism consisting of two consecutive one-electron oxidations of 1 by MPO. Multistage mass spectrometry using stage-specific collision energies permits stepwise deconstruction of modifications of heme enzymes containing covalent links between the heme group and the polypeptide chain.

  12. Single-laboratory validation of a method for the determination of vitamin D3 in dietary supplements by liquid chromatography with tandem mass spectrometry (LC-MS/MS).

    PubMed

    Lam, Victor K M; Hung, Ray C T; Wong, Ella L M; Fok, Johnny Y W; Wong, Yiu-Chung

    2014-01-01

    A single-laboratory validation (SLV) for the analysis of vitamin D3 was performed in four types of dietary supplements (capsules, soft gels, syrups, and tablets) using LC-MS/MS. Samples were treated by alkaline saponification for oil-based soft gels and utilized EDTA solution for capsules, syrups, and tablets prior to n-hexane extraction. Vitamin D3 in sample extracts was separated on a reversed-phase C18 column (100 x 2.1 mm, 2.7 pm) using a mobile phase of a 95 + 5 (v/v) mixture of 5 mM ammonium formate in methanol containing 0.1% formic acid and 5 mM ammonium formate in 0.1% formic acid running at a flow rate of 0.2 mL/min. Vitamin D3 was confirmed by the presence of three fragment ions at m/z 107, 159, and 259 within a defined retention time window from the precursor ion at m/z 385. Quantitation was based on the peak area at m/z 367 to that of the internal standard (d3-vitamin D3) at m/z 370 with reference to the respective response ratios of the calibration standards. The linear response of vitamin D3 ranged from 0.10 to 6.29 mg/L and the correlation coefficient (r) of the six-point calibration curves was > 0.999. Accuracy, in terms of the spiked recoveries from blank syrup and starch powder at three different concentration levels, was 101-103%. Precision, determined by two different analysts over a period of 5 weeks, ranged from 2.7 to 7.0% for the four preparations. The SLV demonstrates the present LC-MS/MS method is reliable and robust for the determination of vitamin D3 in the studied dietary supplements. Considering the attainment of satisfactory SLV results, further validation through intra-laboratory collaborative study is recommended. PMID:24830152

  13. Quantitation of Ubiquinone (Coenzyme Q₁₀) in Serum/Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (ESI-LC-MS/MS).

    PubMed

    Mathieu, Richard E; Riley, Catherine P

    2016-01-01

    Dietary ubiquinone (Coenzyme Q10) is considered an essential co-factor in the mitochondrial respiratory chain responsible for oxidative phosphorylation. This oil-soluble vitamin-like substance is mobile in cellular membranes and plays a unique role in the electron transport chain (ETC). Coenzyme Q10 (CoQ10) is present in most eukaryotic cells and functions as an electron carrier and an antioxidant. Although the exact role of Coenzyme Q10 is often debated; there is a growing interest in the measurement of CoQ10 concentrations particularly in the area of cardiovascular disease, malignancies, exercise physiology, Parkinson's disease, and patients undergoing statin drug therapies. We describe a simple method for the quantitative measurement of the ammonium adduct of Coenzyme Q10 using a high-pressure liquid chromatography combined with positive electrospray ionization tandem mass spectroscopy (ESI-LC-MS/MS) utilizing a 3 μm PFP(2) 50 × 2.0 mm 100 Å column. A stable isotopic deuterated internal standard, in the form of Coenzyme Q10-[D9], is added to the patient serum. The extraneous proteins are precipitated from the sample with ethanol and isolation of the targeted compound is facilitated by the addition of hexane to aide in the cleanup and recovery. Quantitation occurs via a 6-point calibration that is linear from 0.16 to 6.0 μg with an observed error of 6.2 % across the analytical range. PMID:26602118

  14. Reference values for salivary testosterone in adolescent boys and girls determined using Isotope-Dilution Liquid-Chromatography Tandem Mass Spectrometry (ID-LC-MS/MS).

    PubMed

    Büttler, Rahel M; Peper, Jiska S; Crone, Eveline A; Lentjes, Eef G W; Blankenstein, Marinus A; Heijboer, Annemieke C

    2016-05-01

    The measurement of testosterone in saliva is an attractive alternative to serum analysis due to the simple and non-invasive sample collection. In children and adolescents salivary testosterone is mainly measured to investigate whether puberty has started or not. This study aimed to establish reference values for salivary testosterone during puberty in boys and girls. We measured salivary testosterone using ID-LC-MS/MS in a cohort of 131 girls and 123 boys of whom each had salivary testosterone measured at two time points during puberty. Salivary testosterone concentrations start to increase with the start of puberty around eight years and continuously increase up to adult concentrations in the following ten years. Reference values were calculated using the Lambda-Mu-Sigma (LMS)-curve fitting method and provided per year from 8 to 26 years of age in boys and girls. These reference ranges may help clinicians and researchers to interpret salivary testosterone results in both individual patients and study subjects.

  15. Quantitation of Ubiquinone (Coenzyme Q₁₀) in Serum/Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (ESI-LC-MS/MS).

    PubMed

    Mathieu, Richard E; Riley, Catherine P

    2016-01-01

    Dietary ubiquinone (Coenzyme Q10) is considered an essential co-factor in the mitochondrial respiratory chain responsible for oxidative phosphorylation. This oil-soluble vitamin-like substance is mobile in cellular membranes and plays a unique role in the electron transport chain (ETC). Coenzyme Q10 (CoQ10) is present in most eukaryotic cells and functions as an electron carrier and an antioxidant. Although the exact role of Coenzyme Q10 is often debated; there is a growing interest in the measurement of CoQ10 concentrations particularly in the area of cardiovascular disease, malignancies, exercise physiology, Parkinson's disease, and patients undergoing statin drug therapies. We describe a simple method for the quantitative measurement of the ammonium adduct of Coenzyme Q10 using a high-pressure liquid chromatography combined with positive electrospray ionization tandem mass spectroscopy (ESI-LC-MS/MS) utilizing a 3 μm PFP(2) 50 × 2.0 mm 100 Å column. A stable isotopic deuterated internal standard, in the form of Coenzyme Q10-[D9], is added to the patient serum. The extraneous proteins are precipitated from the sample with ethanol and isolation of the targeted compound is facilitated by the addition of hexane to aide in the cleanup and recovery. Quantitation occurs via a 6-point calibration that is linear from 0.16 to 6.0 μg with an observed error of 6.2 % across the analytical range.

  16. Parabens in urine, serum and seminal plasma from healthy Danish men determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Frederiksen, Hanne; Jørgensen, Niels; Andersson, Anna-Maria

    2011-01-01

    Parabens are used as anti-microbial preservatives in a range of consumer products, especially in cosmetics. In vitro and animal studies have shown weak estrogenic and other endocrine disrupting effects of parabens, including reduced testosterone levels in exposed male rats. The knowledge of paraben exposure, distribution and excretion in humans is limited. In this study we determined the concentration of five parabens; methyl-, ethyl-, n-propyl-, n-butyl- and benzylparaben in urine, serum and seminal plasma samples from 60 healthy Danish men. To conduct the study a sensitive and specific method using LC-MS/MS for simultaneous determination of the five parabens was developed for all three different matrices. Highest concentrations of the parabens were found in urine, wherein methyl-, ethyl-, n-propyl- and n-butyl parabens were measurable in 98%, 80%, 98% and 83% of the men, respectively. Benzyl paraben was only measurable in urine from 7% of the men. Methyl- and n-propyl parabens were also measurable in the majority of serum and seminal plasma samples, whereas the other parabens could only be detected in some of the samples. In all the three matrices significant correlations between the parabens were seen. Furthermore, urinary paraben concentrations correlate to the paraben concentrations in both serum and seminal plasma.

  17. Application of Probe Electrospray Ionization Mass Spectrometry (PESI-MS) to Clinical Diagnosis: Solvent Effect on Lipid Analysis

    NASA Astrophysics Data System (ADS)

    Mandal, Mridul Kanti; Yoshimura, Kentaro; Chen, Lee Chuin; Yu, Zhan; Nakazawa, Tadao; Katoh, Ryohei; Fujii, Hideki; Takeda, Sen; Nonami, Hiroshi; Hiraoka, Kenzo

    2012-11-01

    We have examined several combinations of solvents with the aim of optimizing the ionization conditions for molecular diagnosis of malignant tumours by PESI-MS. Although the best conditions may depend on the actual species in the sample, the optimal conditions for renal cell carcinoma (RCC) were achieved by using alcohols. PESI-MS successfully delineated the differential expression of phospholipids (PCs) and triacylglycerols (TAGs) in noncancerous and RCC tissues by using these solvent systems. This study paves the way for the application of PESI-MS in medical samples.

  18. Identification of different respiratory viruses, after a cell culture step, by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS)

    PubMed Central

    Calderaro, Adriana; Arcangeletti, Maria Cristina; Rodighiero, Isabella; Buttrini, Mirko; Montecchini, Sara; Vasile Simone, Rosita; Medici, Maria Cristina; Chezzi, Carlo; De Conto, Flora

    2016-01-01

    In this study matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), a reliable identification method for the diagnosis of bacterial and fungal infections, is presented as an innovative tool to investigate the protein profile of cell cultures infected by the most common viruses causing respiratory tract infections in humans. MALDI-TOF MS was applied to the identification of influenza A and B viruses, adenovirus C species, parainfluenza virus types 1, 2 and 3, respiratory syncytial virus, echovirus, cytomegalovirus and metapneumovirus. In this study MALDI-TOF MS was proposed as a model to be applied to the identification of cultivable respiratory viruses using cell culture as a viral proteins enrichment method to the proteome profiling of virus infected and uninfected cell cultures. The reference virus strains and 58 viruses identified from respiratory samples of subjects with respiratory diseases positive for one of the above mentioned viral agents by cell culture were used for the in vitro infection of suitable cell cultures. The isolated viral particles, concentrated by ultracentrifugation, were used for subsequent protein extraction and their spectra profiles were generated by MALDI-TOF MS analysis. The newly created library allowed us to discriminate between uninfected and respiratory virus infected cell cultures. PMID:27786297

  19. Direct Analysis in Real Time Mass Spectrometry (DART-MS) Analysis of Skin Metabolome Changes in the Ultraviolet B-Induced Mice.

    PubMed

    Park, Hye Min; Kim, Hye Jin; Jang, Young Pyo; Kim, Sun Yeou

    2013-11-01

    Ultraviolet (UV) radiation is a major environmental factor that leads to acute and chronic reactions in the human skin. UV exposure induces wrinkle formation, DNA damage, and generation of reactive oxygen species (ROS). Most mechanistic studies of skin physiology and pharmacology related with UV-irradiated skin have focused on proteins and their related gene expression or single- targeted small molecules. The present study identified and analyzed the alteration of skin metabolites following UVB irradiation and topical retinyl palmitate (RP, 5%) treatment in hairless mice using direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) with multivariate analysis. Under the negative ion mode, the DART ion source successfully ionized various fatty acids including palmitoleic and linolenic acid. From DART-TOF-MS fingerprints measured in positive mode, the prominent dehydrated ion peak (m/z: 369, M+H-H2O) of cholesterol was characterized in all three groups. In positive mode, the discrimination among three groups was much clearer than that in negative mode by using multivariate analysis of orthogonal partial-least squares-discriminant analysis (OPLS-DA). DART-TOF-MS can ionize various small organic molecules in living tissues and is an efficient alternative analytical tool for acquiring full chemical fingerprints from living tissues without requiring sample preparation. DART-MS measurement of skin tissue with multivariate analysis proved to be a powerful method to discriminate between experimental groups and to find biomarkers for various experiment models in skin dermatological research.

  20. Direct Analysis in Real Time Mass Spectrometry (DART-MS) Analysis of Skin Metabolome Changes in the Ultraviolet B-Induced Mice

    PubMed Central

    Park, Hye Min; Kim, Hye Jin; Jang, Young Pyo; Kim, Sun Yeou

    2013-01-01

    Ultraviolet (UV) radiation is a major environmental factor that leads to acute and chronic reactions in the human skin. UV exposure induces wrinkle formation, DNA damage, and generation of reactive oxygen species (ROS). Most mechanistic studies of skin physiology and pharmacology related with UV-irradiated skin have focused on proteins and their related gene expression or single- targeted small molecules. The present study identified and analyzed the alteration of skin metabolites following UVB irradiation and topical retinyl palmitate (RP, 5%) treatment in hairless mice using direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) with multivariate analysis. Under the negative ion mode, the DART ion source successfully ionized various fatty acids including palmitoleic and linolenic acid. From DART-TOF-MS fingerprints measured in positive mode, the prominent dehydrated ion peak (m/z: 369, M+H-H2O) of cholesterol was characterized in all three groups. In positive mode, the discrimination among three groups was much clearer than that in negative mode by using multivariate analysis of orthogonal partial-least squares-discriminant analysis (OPLS-DA). DART-TOF-MS can ionize various small organic molecules in living tissues and is an efficient alternative analytical tool for acquiring full chemical fingerprints from living tissues without requiring sample preparation. DART-MS measurement of skin tissue with multivariate analysis proved to be a powerful method to discriminate between experimental groups and to find biomarkers for various experiment models in skin dermatological research. PMID:24404338

  1. Direct Analysis in Real Time Mass Spectrometry (DART-MS) Analysis of Skin Metabolome Changes in the Ultraviolet B-Induced Mice.

    PubMed

    Park, Hye Min; Kim, Hye Jin; Jang, Young Pyo; Kim, Sun Yeou

    2013-11-01

    Ultraviolet (UV) radiation is a major environmental factor that leads to acute and chronic reactions in the human skin. UV exposure induces wrinkle formation, DNA damage, and generation of reactive oxygen species (ROS). Most mechanistic studies of skin physiology and pharmacology related with UV-irradiated skin have focused on proteins and their related gene expression or single- targeted small molecules. The present study identified and analyzed the alteration of skin metabolites following UVB irradiation and topical retinyl palmitate (RP, 5%) treatment in hairless mice using direct analysis in real time (DART) time-of-flight mass spectrometry (TOF-MS) with multivariate analysis. Under the negative ion mode, the DART ion source successfully ionized various fatty acids including palmitoleic and linolenic acid. From DART-TOF-MS fingerprints measured in positive mode, the prominent dehydrated ion peak (m/z: 369, M+H-H2O) of cholesterol was characterized in all three groups. In positive mode, the discrimination among three groups was much clearer than that in negative mode by using multivariate analysis of orthogonal partial-least squares-discriminant analysis (OPLS-DA). DART-TOF-MS can ionize various small organic molecules in living tissues and is an efficient alternative analytical tool for acquiring full chemical fingerprints from living tissues without requiring sample preparation. DART-MS measurement of skin tissue with multivariate analysis proved to be a powerful method to discriminate between experimental groups and to find biomarkers for various experiment models in skin dermatological research. PMID:24404338

  2. Analysis of Non-Enzymatically Glycated Peptides: Neutral-Loss Triggered MS3 Versus Multi-Stage Activation Tandem Mass Spectrometry

    SciTech Connect

    Zhang, Qibin; Petyuk, Vladislav A.; Schepmoes, Athena A.; Orton, Daniel J.; Monroe, Matthew E.; Yang, Feng; Smith, Richard D.; Metz, Thomas O.

    2008-10-15

    Non-enzymatic glycation of tissue proteins has important implications in the development of complications of diabetes mellitus. While electron transfer dissociation (ETD) has been shown to outperform collision-induced dissociation (CID) in sequencing glycated peptides by tandem mass spectrometry, ETD instrumentation is not yet available in all laboratories. In this study, we evaluated different advanced CID techniques (i.e., neutral-loss triggered MS3 and multi-stage activation) during LC-MSn analyses of Amadori-modified peptides enriched from human serum glycated in vitro. During neutral-loss triggered MS3 experiments, MS3 scans triggered by neutral-losses of 3 H2O or 3 H2O + HCHO produced similar results in terms of glycated peptide identifications. However, neutral losses of 3 H2O resulted in significantly more glycated peptide identifications during multi-stage activation experiments. Overall, the multi-stage activation approach produced more glycated peptide identifications, while the neutral-loss triggered MS3 approach resulted in much higher specificity. Both techniques offer a viable alternative to ETD for identifying glycated peptides when that method is unavailable.

  3. Performances of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Rapid Identification of Bacteria in Routine Clinical Microbiology

    PubMed Central

    Grare, Marion; Prere, Marie-Françoise; Segonds, Christine; Marty, Nicole; Oswald, Eric

    2012-01-01

    Rapid and cost-effective matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based systems will replace conventional phenotypic methods for routine identification of bacteria. We report here the first evaluation of the new MALDI-TOF MS-based Vitek MS system in a large clinical microbiology laboratory. This system uses an original spectrum classifier algorithm and a specific database designed for the identification of clinically relevant species. We have tested 767 routine clinical isolates representative of 50 genera and 124 species. Vitek MS-based identifications were performed by means of a single deposit on a MALDI disposable target without any prior extraction step and compared with reference identifications obtained mainly with the VITEK2 phenotypic system; if the identifications were discordant, molecular techniques provided reference identifications. The Vitek MS system provided 96.2% correct identifications to the species level (86.7%), to the genus level (8.2%), or within a range of species belonging to different genera (1.3%). Conversely, 1.3% of isolates were misidentified and 2.5% were unidentified, partly because the species was not included in the database; a second deposit provided a successful identification for 0.8% of isolates unidentified with the first deposit. The Vitek MS system is a simple, convenient, and accurate method for routine bacterial identification with a single deposit, considering the high bacterial diversity studied and as evidenced by the low prevalence of species without correct identification. In addition to a second deposit in uncommon cases, expanding the spectral database is expected to further enhance performances. PMID:22593596

  4. Comparative Investigation between In Situ Laser Ablation Versus Bulk Sample (Solution Mode) Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Analysis of Trinitite Post-Detonation Materials.

    PubMed

    Dustin, Megan K; Koeman, Elizabeth C; Simonetti, Antonio; Torrano, Zachary; Burns, Peter C

    2016-09-01

    In the event of the interception of illicit nuclear materials or detonation of a nuclear device, timely and accurate deciphering of the chemical and isotopic composition of pertinent samples is pivotal in enhancing both nuclear security and source attribution. This study reports the results from a first time (to our knowledge), detailed comparative investigation conducted of Trinitite post-detonation materials using both solution mode (SM) and laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) techniques. Trace element abundances determined for bulk Trinitite samples subsequent to digestion and preparation for SM-ICP-MS analysis compare favorably to calculated median concentrations based on LA-ICP-MS analyses for the identical samples. The trace element concentrations obtained by individual LA-ICP-MS analyses indicate a large scatter compared to the corresponding bulk sample SM-ICP-MS results for the same sample; this feature can be attributed to the incorporation into the blast melt of specific, precursor accessory minerals (minerals in small quantities, such as carbonates, sulfates, chlorites, clay, and mafic minerals) present at ground zero. The favorable comparison reported here validates and confirms the use of the LA-ICP-MS technique in obtaining accurate forensic information at high spatial resolution in nuclear materials for source attribution purposes. This investigation also reports device-like (240)Pu/(239)Pu ratios (∼0.022) for Pu-rich regions of the blast melt that are also characterized by higher Ca and U contents, which is consistent with results from previous studies. PMID:27566253

  5. Performances of the Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for rapid identification of bacteria in routine clinical microbiology.

    PubMed

    Dubois, Damien; Grare, Marion; Prere, Marie-Françoise; Segonds, Christine; Marty, Nicole; Oswald, Eric

    2012-08-01

    Rapid and cost-effective matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based systems will replace conventional phenotypic methods for routine identification of bacteria. We report here the first evaluation of the new MALDI-TOF MS-based Vitek MS system in a large clinical microbiology laboratory. This system uses an original spectrum classifier algorithm and a specific database designed for the identification of clinically relevant species. We have tested 767 routine clinical isolates representative of 50 genera and 124 species. Vitek MS-based identifications were performed by means of a single deposit on a MALDI disposable target without any prior extraction step and compared with reference identifications obtained mainly with the VITEK2 phenotypic system; if the identifications were discordant, molecular techniques provided reference identifications. The Vitek MS system provided 96.2% correct identifications to the species level (86.7%), to the genus level (8.2%), or within a range of species belonging to different genera (1.3%). Conversely, 1.3% of isolates were misidentified and 2.5% were unidentified, partly because the species was not included in the database; a second deposit provided a successful identification for 0.8% of isolates unidentified with the first deposit. The Vitek MS system is a simple, convenient, and accurate method for routine bacterial identification with a single deposit, considering the high bacterial diversity studied and as evidenced by the low prevalence of species without correct identification. In addition to a second deposit in uncommon cases, expanding the spectral database is expected to further enhance performances.

  6. Analysis of ethyl glucuronide in hair samples by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS).

    PubMed

    Cabarcos, Pamela; Hassan, Huda M; Tabernero, María Jesús; Scott, Karen S

    2013-07-01

    Many different biomarkers can be used to evaluate ethanol intake. Ethyl glucuronide (EtG) is a direct phase II and minor metabolite of ethanol formed through the UDP-glucuronosyl transferase-catalyzed conjugation of ethanol with glucuronic acid. Its investigation is of interest in both clinical and forensic contexts because of the wide window of detection. A sensitive LC-MS/MS procedure has been developed and fully validated according to the guidelines of forensic toxicology for the analysis of EtG in hair. Sample preparation and chromatographic separation were thoroughly optimized. The analysis was performed in the multiple reaction monitoring mode using the transitions m/z 221 → 203 (for the quantification) and 221 → 85 or 75 (for the qualification) for EtG, and m/z 226 → 208 (for quantification) and 226 → 75 or 85 (for qualification) for EtG-D5, used as the internal standard. Analyses were carried out using an Inertsil ODS-3 column (100 × 3 mm i.d., 3 µm particle size) and a mobile phase composed of formic acid and acetonitrile. Various SPE cartridges and solvents were tested in order to obtain the highest recoveries and cleanest extracts. The assay linearity of EtG was confirmed over the range from 20 to 2500 pg mg(-1), with a coefficient of determination (R(2) ) above 0.99. The lower limit of quantitation (LLOQ) was 20 pg mg(-1) and the limit of detection was 10 pg mg(-1). Intra- and inter-day assays were less than 15% except at the LLOQ (20%). The analytical method was applied to 72 post-mortem hair samples. EtG concentration in the hair ranged from 0 to 653 pg mg(-1) hair. PMID:22234871

  7. In-house-validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for survey of acrylamide in various processed foods from Korean market.

    PubMed

    Lee, Sanghee; Yoo, Miyoung; Koo, Minseon; Kim, Hyun Jung; Kim, Meehye; Park, Sung-Kug; Shin, Dongbin

    2013-09-01

    Acrylamide (AA) is a chemical found in starchy foods that have been cooked at high temperatures. The objective of this study is to monitor the levels of AA in a total of 274 samples of potato chips, chips (except potato chips), biscuits, French fries, breakfast cereals, chocolate products, tea, seasoned laver, and nut products sampled in Korean market. These processed foods include (1) potato chips, (2) chips (except potato chips), (3) biscuits, (4) French fries, (5) breakfast cereals, (6) chocolate products, (7) tea, (8) seasoned laver, and (9) nut products. Samples used for this study were cleaned up using HLB Oasis polymeric and Accucat mixed-mode anion and cation exchange solid-phase extraction cartridge. Liquid chromatography-tandem mass spectroscopy (LC-MS/MS) was validated in-house as an efficient analytical method for the routine analysis of AA in various food products. AA was detected with a Fortis dC18 (1.7 μm, 100 mm × 2.1 mm) column using 0.5% methanol/0.1% acetic acid in water as the mobile phase. Good results were obtained with respect to repeatability (RSDs < 5%). The recoveries obtained for a variety of food matrices ranged between 94.5% and 107.6%. Quantification during routine monitoring was sensitive enough to detect AA at a concentration of 10 μg/kg. A total of 274 food samples were analyzed for AA. The AA levels in the food groups were in the following order: potato chips > French fries > biscuits > tea > chips (except potato chips) > seasoned laver > breakfast cereals > chocolate products > nut products. AA was detected at levels ranging from not detectable to 1435 μg/kg. PMID:24804047

  8. In-house-validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for survey of acrylamide in various processed foods from Korean market.

    PubMed

    Lee, Sanghee; Yoo, Miyoung; Koo, Minseon; Kim, Hyun Jung; Kim, Meehye; Park, Sung-Kug; Shin, Dongbin

    2013-09-01

    Acrylamide (AA) is a chemical found in starchy foods that have been cooked at high temperatures. The objective of this study is to monitor the levels of AA in a total of 274 samples of potato chips, chips (except potato chips), biscuits, French fries, breakfast cereals, chocolate products, tea, seasoned laver, and nut products sampled in Korean market. These processed foods include (1) potato chips, (2) chips (except potato chips), (3) biscuits, (4) French fries, (5) breakfast cereals, (6) chocolate products, (7) tea, (8) seasoned laver, and (9) nut products. Samples used for this study were cleaned up using HLB Oasis polymeric and Accucat mixed-mode anion and cation exchange solid-phase extraction cartridge. Liquid chromatography-tandem mass spectroscopy (LC-MS/MS) was validated in-house as an efficient analytical method for the routine analysis of AA in various food products. AA was detected with a Fortis dC18 (1.7 μm, 100 mm × 2.1 mm) column using 0.5% methanol/0.1% acetic acid in water as the mobile phase. Good results were obtained with respect to repeatability (RSDs < 5%). The recoveries obtained for a variety of food matrices ranged between 94.5% and 107.6%. Quantification during routine monitoring was sensitive enough to detect AA at a concentration of 10 μg/kg. A total of 274 food samples were analyzed for AA. The AA levels in the food groups were in the following order: potato chips > French fries > biscuits > tea > chips (except potato chips) > seasoned laver > breakfast cereals > chocolate products > nut products. AA was detected at levels ranging from not detectable to 1435 μg/kg.

  9. Continental bottled water assessment by stir bar sorptive extraction followed by gas chromatography-tandem mass spectrometry (SBSE-GC-MS/MS).

    PubMed

    Guart, Albert; Calabuig, Ignacio; Lacorte, Silvia; Borrell, Antonio

    2014-02-01

    This study was aimed to determine the presence of 69 organic contaminants in 77 representative bottled waters collected from 27 countries all over the world. All water samples were contained in polyethylene terephthalate bottles. Target compounds were (1) environmental contaminants (including 13 polycyclic aromatic hydrocarbons (PAHs), 31 pesticides including organochlorine (OCPs), organophosphorus, and pyrethroids; 7 polychlorinated biphenyls (PCBs); and 7 triazines) and (2) plasticizers (including 6 phthalates and 5 other compounds). Samples were analyzed by stir bar sorptive extraction followed by gas chromatography-tandem mass spectrometry. PAHs, OCPs, PCBs, and triazines, which are indicators of groundwater pollution, were not detected in most of the samples, except for naphthalene (0.005-0.202 μg/L, n = 16). On the other hand, plastic components were detected in 77 % of the samples. Most frequently detected compounds were dimethyl phthalate and benzophenone at concentrations of 0.005-0.125 (n = 41) and 0.014-0.921 (n = 32), respectively. Levels detected are discussed in terms of contamination origin and geographical distribution. Target compounds were detected at low concentrations. Results obtained showed the high quality of bottled water in the different countries around the world.

  10. Data on the identification of protein interactors with the Evening Complex and PCH1 in Arabidopsis using tandem affinity purification and mass spectrometry (TAP-MS).

    PubMed

    Huang, He; Alvarez, Sophie; Nusinow, Dmitri A

    2016-09-01

    Tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis is a powerful biochemical approach to identify protein-protein associations. Here we describe two datasets generated by a series of TAP-MS analyses to co-purify proteins associated with either ELF3 or ELF4 of the Evening Complex (EC) ("Identification of Evening Complex Associated Proteins in Arabidopsis by Affinity Purification and Mass Spectrometry" (Huang et al., 2016a) [1]) or proteins associated with PCH1, which is a newly identified output of the circadian clock to regulate photoperiodic growth in Arabidopsis thaliana ("PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis" (Huang et al. 2016b) [2]). We used either ELF3, ELF4 or PCH1 fused to a C-terminal tandem affinity tag (6xHis-3xFLAG) as baits and conducted purifications in various genetic mutant backgrounds. These data are discussed in recent publications [1,2], and are deposited at the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PRIDE: PXD002606 (for EC) and PRIDE: PXD003352 (for PCH1).

  11. Data on the identification of protein interactors with the Evening Complex and PCH1 in Arabidopsis using tandem affinity purification and mass spectrometry (TAP-MS).

    PubMed

    Huang, He; Alvarez, Sophie; Nusinow, Dmitri A

    2016-09-01

    Tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis is a powerful biochemical approach to identify protein-protein associations. Here we describe two datasets generated by a series of TAP-MS analyses to co-purify proteins associated with either ELF3 or ELF4 of the Evening Complex (EC) ("Identification of Evening Complex Associated Proteins in Arabidopsis by Affinity Purification and Mass Spectrometry" (Huang et al., 2016a) [1]) or proteins associated with PCH1, which is a newly identified output of the circadian clock to regulate photoperiodic growth in Arabidopsis thaliana ("PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis" (Huang et al. 2016b) [2]). We used either ELF3, ELF4 or PCH1 fused to a C-terminal tandem affinity tag (6xHis-3xFLAG) as baits and conducted purifications in various genetic mutant backgrounds. These data are discussed in recent publications [1,2], and are deposited at the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PRIDE: PXD002606 (for EC) and PRIDE: PXD003352 (for PCH1). PMID:27274533

  12. Rapid and sensitive quantification of levoglucosan in aerosols by high-performance anion-exchange chromatography with positive electrospray ionization mass spectrometry (HPAEC-positive ESI-MS)

    NASA Astrophysics Data System (ADS)

    Asakawa, Daichi; Furuichi, Yuko; Yamamoto, Atsushi; Oku, Yuichiro; Funasaka, Kunihiro

    2015-12-01

    A convenient quantification method for underivatized levoglucosan, which is a tracer for biomass burning influenced particulate matter (PM), has been established using high-performance anion-exchange chromatography (HPAEC) coupled to positive electrospray ionization mass spectrometry ((+)ESI-MS). Levoglucosan was chromatographically separated from its isomers (mannosan and galactosan) and detected selectively with positive ESI-MS. Limits of detection and quantification for this method were 0.40 and 1.3 ng mL-1, respectively. A comparison of simultaneous measurements by this method and conventional derivatization gas chromatography/mass spectrometry showed a good linearity with a slope of 1.008 and a determination coefficient of 0.9932. The developed method was applied to ambient suspended particulate matter hourly collected by continuous particulate monitors at 10 stations. The hourly concentration of levoglucosan during August 9-11, 2011, was 1.7-918 ng m-3 and its distribution indicated the transportation of biomass burning aerosols of a forest fire. This is the first report of horizontal distribution of the hourly levoglucosan concentration in Japan.

  13. Isotope dilution quantification of ultratrace gamma-glutamyl-Se-methylselenocysteine species using HPLC with enhanced ICP-MS detection by ultrasonic nebulisation or carbon-loaded plasma.

    PubMed

    Goenaga Infante, Heidi; Ovejero Bendito, María del Carmen; Cámara, Carmen; Evans, Linda; Hearn, Ruth; Moesgaard, Sven

    2008-04-01

    A method for the accurate determination of ultratrace selenium species of relevance to cancer research, such as gamma-glutamyl-Se-methylselenocysteine (gamma-glutamyl-SeMC), using species-specific double isotope dilution analysis (IDA) with HPLC-ICP-MS is reported for the first time. The (77)Se-enriched gamma-glutamyl-SeMC spike was produced in-house by collecting the fraction at the retention time of the gamma-glutamyl-SeMC peak from a chromatographed aqueous extract of (77)Se-enriched yeast, pooling the collected fractions and freeze-drying the homogenate. The Se content of this spike was characterised using reverse isotope dilution mass spectrometry (IDMS) and the isotopic composition of this spike was checked prior to quantification of the natural abundance dipeptide species in garlic using speciated IDA. The extraction of the gamma-glutamyl-SeMC species in water was performed in a sonication bath for 2 h after adding an appropriate quantity of (77)Se-enriched gamma-glutamyl-SeMC to 50 mg of garlic to give optimal (78)Se/(77)Se and (82)Se/(77)Se ratios of 1.5 and 0.6, respectively. The effect of ultrasonic nebulisation, in comparison with the loading of the ICP with carbon (through the addition of methane gas on-line), on the detection of Se associated with gamma-glutamyl-SeMC using collision/reaction cell ICP-MS with hydrogen as collision gas was investigated. Sensitivity enhancements of approximately fourfold and twofold were achieved using USN and methane mixed plasma, respectively, in comparison with conventional nebulisation and conventional Ar ICP-MS. However, an approximately twofold improvement in the detection limit was achieved using both approaches (42 ng kg(-1) for (78)Se using peak height measurements). The use of species-specific IDMS enabled quantification of the dipeptide species at ng g(-1) levels (603 ng g(-1) Se) in the complex food matrix with a relative standard deviation (RSD, n = 4) of 4.5%, which was approximately half that obtained

  14. Quantification of Al2O3 nanoparticles in human cell lines applying inductively coupled plasma mass spectrometry (neb-ICP-MS, LA-ICP-MS) and flow cytometry-based methods.

    PubMed

    Böhme, Steffi; Stärk, Hans-Joachim; Meißner, Tobias; Springer, Armin; Reemtsma, Thorsten; Kühnel, Dana; Busch, Wibke

    2014-01-01

    In order to quantify and compare the uptake of aluminum oxide nanoparticles of three different sizes into two human cell lines (skin keratinocytes (HaCaT) and lung epithelial cells (A549)), three analytical methods were applied: digestion followed by nebulization inductively coupled plasma mass spectrometry (neb-ICP-MS), direct laser ablation ICP-MS (LA-ICP-MS), and flow cytometry. Light and electron microscopy revealed an accumulation and agglomeration of all particle types within the cell cytoplasm, whereas no particles were detected in the cell nuclei. The internalized Al2O3 particles exerted no toxicity in the two cell lines after 24 h of exposure. The smallest particles with a primary particle size (x BET) of 14 nm (Alu1) showed the lowest sedimentation velocity within the cell culture media, but were calculated to have settled completely after 20 h. Alu2 (x BET = 111 nm) and Alu3 (x BET = 750 nm) were calculated to reach the cell surface after 7 h and 3 min, respectively. The internal concentrations determined with the different methods lay in a comparable range of 2-8 µg Al2O3/cm(2) cell layer, indicating the suitability of all methods to quantify the nanoparticle uptake. Nevertheless, particle size limitations of analytical methods using optical devices were demonstrated for LA-ICP-MS and flow cytometry. Furthermore, the consideration and comparison of particle properties as parameters for particle internalization revealed the particle size and the exposure concentration as determining factors for particle uptake. PMID:25285033

  15. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method extension to quantify simultaneously melamine and cyanuric acid in egg powder and soy protein in addition to milk products.

    PubMed

    Rodriguez Mondal, Ana Mary; Desmarchelier, Aurélien; Konings, Erik; Acheson-Shalom, Ruth; Delatour, Thierry

    2010-11-24

    As a consequence of the adulteration of infant formulas and milk powders with melamine (MEL) in China in 2008, much attention has been devoted to the analysis of MEL [and cyanuric acid (CA)] in dairy products. Several methods based on high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), nuclear magnetic resonance (NMR), or Raman spectroscopy have been described in the literature. However, no method is available for the simultaneous determination of MEL and CA in other raw materials, which are considered as high-risk materials for economically motivated adulteration. The present paper reports the results of an interlaboratory-based performance evaluation conducted with seven laboratories worldwide. The purpose was to demonstrate the ability of a cleanup-free LC-MS/MS method, originally developed for cow's milk and milk-powdered infant formula, to quantify MEL and CA in egg powder and soy protein. Limit of detection (LOD) and limit of quantification (LOQ) were 0.02 and 0.05 mg/kg for MEL in egg powder and soy protein, respectively. For CA, LOD and LOQ were 0.05 and 0.10 mg/kg in egg powder and 1.0 and 1.50 mg/kg in soy protein, respectively. Recoveries ranged within a 97-113% range for both MEL and CA in egg powder and soy protein. Reproducibility values (RSD(R)) from seven laboratories were within a 5.4-11.7% range for both analytes in the considered matrices. Horwitz ratio (HorRat) values between 0.4 and 0.7 indicate acceptable among-laboratory precision for the method described. PMID:21038852

  16. Development of a highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of phenylethanolamine A in tissue and feed samples and confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS).

    PubMed

    Cao, Biyun; He, Guangzhao; Yang, Hong; Chang, Huafang; Li, Shuqun; Deng, Anping

    2013-10-15

    Phenylethanolamine A (PA) is a new emerged β-adrenergic agonist illegally used as feed additives for growth promotion. In this study, a highly sensitive and specific indirect competitive enzyme-linked immunosorbent assay (ELISA) for the detection of PA in tissue and feed samples was developed and confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS). By reduction of nitryl group to amino group, the PA derivative was synthesized and coupled to carrier proteins with diazobenzidine method. The antisera obtained from four immunized rabbits were characterized in terms of sensitivity and specificity. All antisera displayed high sensitivity with IC50 values lower than 0.48 ng mL(-1). The most sensitive ELISA was established with IC50 and limit of detection (LOD) values of 0.049 ng mL(-1) and 0.003 ng mL(-1), respectively. The cross-reactivity (CR) values of the antisera with three frequently used β-adrenergic agonists (clenbuterol, salbutamol and ractopamine) were lesser than 0.39%; there was no CR of the antisera with other six compounds including two structurally related substances (isoproterenol, phenylephrine). To investigate the accuracy and precision of the assay, swine kidney, liver, meat and feed samples were fortified with PA at different content and analyzed by ELISA. Acceptable recovery rates of 92.2-113.7% and intra-assay coefficients of variation of 3.8-10.9% (n=3) were achieved. Seven spiked samples were simultaneously analyzed by ELISA and LC-MS/MS. There was a high correlation coefficient of 0.9956 (n=7) between the two methods. The proposed ELISA proven to be a feasible quantitative/screening method for PA analysis in tissue and feed samples with the properties of high sensitivity and specificity, high sample throughput and low expensive.

  17. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method extension to quantify simultaneously melamine and cyanuric acid in egg powder and soy protein in addition to milk products.

    PubMed

    Rodriguez Mondal, Ana Mary; Desmarchelier, Aurélien; Konings, Erik; Acheson-Shalom, Ruth; Delatour, Thierry

    2010-11-24

    As a consequence of the adulteration of infant formulas and milk powders with melamine (MEL) in China in 2008, much attention has been devoted to the analysis of MEL [and cyanuric acid (CA)] in dairy products. Several methods based on high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), nuclear magnetic resonance (NMR), or Raman spectroscopy have been described in the literature. However, no method is available for the simultaneous determination of MEL and CA in other raw materials, which are considered as high-risk materials for economically motivated adulteration. The present paper reports the results of an interlaboratory-based performance evaluation conducted with seven laboratories worldwide. The purpose was to demonstrate the ability of a cleanup-free LC-MS/MS method, originally developed for cow's milk and milk-powdered infant formula, to quantify MEL and CA in egg powder and soy protein. Limit of detection (LOD) and limit of quantification (LOQ) were 0.02 and 0.05 mg/kg for MEL in egg powder and soy protein, respectively. For CA, LOD and LOQ were 0.05 and 0.10 mg/kg in egg powder and 1.0 and 1.50 mg/kg in soy protein, respectively. Recoveries ranged within a 97-113% range for both MEL and CA in egg powder and soy protein. Reproducibility values (RSD(R)) from seven laboratories were within a 5.4-11.7% range for both analytes in the considered matrices. Horwitz ratio (HorRat) values between 0.4 and 0.7 indicate acceptable among-laboratory precision for the method described.

  18. Determination of ethyl glucuronide in hair samples of Chinese people by protein precipitation (PPT) and large volume injection-gas chromatography-tandem mass spectrometry (LVI-GC/MS/MS).

    PubMed

    Shi, Yan; Shen, Baohua; Xiang, Ping; Yan, Hui; Shen, Min

    2010-11-15

    Ethyl glucuronide (EtG) has been shown to be a suitable marker of excessive alcohol consumption. Determination of EtG in hair samples may help to differentiate social drinkers from alcoholics, and this testing can be widely used in forensic science, treatment programs, workplaces, military bases as well as driving ability test to provide legal proof of drinking. A method for determination of EtG in hair samples using large volume injection-gas chromatography-tandem mass spectrometry (LVI-GC/MS/MS) was developed and validated. Hair samples (in 1 mL deionized water) were ultrasonicated for 1h and incubated overnight; these samples were then deproteinated to remove impurities and derivatisated with 15 μL of pyridine and 30 μL of BSTFA. EtG was detected using GC/MS/MS in multiple-reaction monitoring mode. This method exhibited good linearity: y=0.0036 x+0.0437, R²=0.9993, the limit of detection and the limit of quantification were 5 pg/mg and 10 pg/mg, respectively. The extraction recoveries were more than 60%, and the inter-day and intra-day relative standard deviations (RSD) were less than 15%. This method has been applied to the analysis of EtG in hair samples from 21 Chinese subjects. The results for samples obtained from all of those who were teetotallers were negative, and the results for the other 15 samples ranged from 10 to 78 pg/mg, except for one negative sample. These data are the basis for interpretation of alcohol abuse. PMID:20977979

  19. Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of glucocorticoid residues in edible tissues of swine, cattle, sheep, and chicken.

    PubMed

    Chen, Dongmei; Tao, Yanfei; Liu, Zhaoying; Liu, Zhenli; Wang, Yulian; Huang, Lingli; Yuan, Zonghui

    2010-10-01

    A confirmatory and quantitative method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the presence of eight glucocorticoids (prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone, and fludrocortisone) in the muscles and livers of swine, cattle, and sheep and the muscle of chicken is described. After deconjugation in alkali media, samples were extracted with ethyl acetate for glucocorticoids followed by solid-phase extraction clean-up and reconstitution in the LC mobile phase. The hydrolysis procedure with sodium hydroxide was used to reduce handling time. A single-step solid-phase extraction method was optimized which is suitable for the clean-up of the compounds of interest in many diverse tissue matrices. LC separations were performed on a C(18) column with gradient elution using acetonitrile and water (containing 0.2% formic acid) and the two epimers betamethasone and dexamethasone were successfully separated. LC-electrospray ionization (ESI)-MS/MS in negative mode with selected reaction monitoring (SRM) mode was performed to improve method sensitivity and reduce matrix interference. Two SRM transitions were used for each compound. The recovery of glucocorticoids spiked at levels of 0.5-16 microg kg(-1) ranged from 55% to 107%; the between-day relative standard deviations were no more than 15%. The limits of quantification were 0.5-2.0 microg kg(-1) in muscle and 1-4 microg kg(-1) in liver. The optimized procedure was successfully applied to monitor the food at the 2008 Summer Olympics Games in Beijing, China, demonstrating the method to be simple, fast, robust, and suitable for identification and quantification of glucocorticoids residues in foods of animal origin.

  20. Multicenter Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Gram-Positive Aerobic Bacteria

    PubMed Central

    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; Westblade, Lars F.; Ferraro, Mary Jane; Branda, John A.

    2013-01-01

    Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261

  1. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize copper, zinc and mercury along grizzly bear hair providing estimate of diet.

    PubMed

    Noël, Marie; Christensen, Jennie R; Spence, Jody; Robbins, Charles T

    2015-10-01

    We enhanced an existing technique, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to function as a non-lethal tool in the temporal characterization of trace element exposure in wild mammals. Mercury (Hg), copper (Cu), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) were analyzed along the hair of captive and wild grizzly bears (Ursus arctos horribilis). Laser parameters were optimized (consecutive 2000 μm line scans along the middle line of the hair at a speed of 50 μm/s; spot size=30 μm) for consistent ablation of the hair. A pressed pellet of reference material DOLT-2 and sulfur were used as external and internal standards, respectively. Our newly adapted method passed the quality control tests with strong correlations between trace element concentrations obtained using LA-ICP-MS and those obtained with regular solution-ICP-MS (r(2)=0.92, 0.98, 0.63, 0.57, 0.99 and 0.90 for Hg, Fe, Cu, Zn, Cd and Pb, respectively). Cross-correlation analyses revealed good reproducibility between trace element patterns obtained from hair collected from the same bear. One exception was Cd for which external contamination was observed resulting in poor reproducibility. In order to validate the method, we used LA-ICP-MS on the hair of five captive grizzly bears fed known and varying amounts of cutthroat trout over a period of 33 days. Trace element patterns along the hair revealed strong Hg, Cu and Zn signals coinciding with fish consumption. Accordingly, significant correlations between Hg, Cu, and Zn in the hair and Hg, Cu, and Zn intake were evident and we were able to develop accumulation models for each of these elements. While the use of LA-ICP-MS for the monitoring of trace elements in wildlife is in its infancy, this study highlights the robustness and applicability of this newly adapted method.

  2. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize copper, zinc and mercury along grizzly bear hair providing estimate of diet.

    PubMed

    Noël, Marie; Christensen, Jennie R; Spence, Jody; Robbins, Charles T

    2015-10-01

    We enhanced an existing technique, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to function as a non-lethal tool in the temporal characterization of trace element exposure in wild mammals. Mercury (Hg), copper (Cu), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) were analyzed along the hair of captive and wild grizzly bears (Ursus arctos horribilis). Laser parameters were optimized (consecutive 2000 μm line scans along the middle line of the hair at a speed of 50 μm/s; spot size=30 μm) for consistent ablation of the hair. A pressed pellet of reference material DOLT-2 and sulfur were used as external and internal standards, respectively. Our newly adapted method passed the quality control tests with strong correlations between trace element concentrations obtained using LA-ICP-MS and those obtained with regular solution-ICP-MS (r(2)=0.92, 0.98, 0.63, 0.57, 0.99 and 0.90 for Hg, Fe, Cu, Zn, Cd and Pb, respectively). Cross-correlation analyses revealed good reproducibility between trace element patterns obtained from hair collected from the same bear. One exception was Cd for which external contamination was observed resulting in poor reproducibility. In order to validate the method, we used LA-ICP-MS on the hair of five captive grizzly bears fed known and varying amounts of cutthroat trout over a period of 33 days. Trace element patterns along the hair revealed strong Hg, Cu and Zn signals coinciding with fish consumption. Accordingly, significant correlations between Hg, Cu, and Zn in the hair and Hg, Cu, and Zn intake were evident and we were able to develop accumulation models for each of these elements. While the use of LA-ICP-MS for the monitoring of trace elements in wildlife is in its infancy, this study highlights the robustness and applicability of this newly adapted method. PMID:26005744

  3. Feasibility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) networking in university hospitals in Brussels.

    PubMed

    Martiny, D; Cremagnani, P; Gaillard, A; Miendje Deyi, V Y; Mascart, G; Ebraert, A; Attalibi, S; Dediste, A; Vandenberg, O

    2014-05-01

    The mutualisation of analytical platforms might be used to address rising healthcare costs. Our study aimed to evaluate the feasibility of networking a unique matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) system for common use in several university hospitals in Brussels, Belgium. During a one-month period, 1,055 successive bacterial isolates from the Brugmann University Hospital were identified on-site using conventional techniques; these same isolates were also identified using a MALDI-TOF MS system at the Porte de Hal Laboratory by sending target plates and identification projects via transportation and the INFECTIO_MALDI software (Infopartner, Nancy, France), respectively. The occurrence of transmission problems (<2 %) and human errors (<1 %) suggested that the system was sufficiently robust to be implemented in a network. With a median time-to-identification of 5 h and 11 min (78 min, min-max: 154-547), MALDI-TOF MS networking always provided a faster identification result than conventional techniques, except when chromogenic culture media and oxidase tests were used (p < 0.0001). However, the limited clinical benefits of the chromogenic culture media do not support their extra cost. Our financial analysis also suggested that MALDI-TOF MS networking could lead to substantial annual cost savings. MALDI-TOF MS networking presents many advantages, and few conventional techniques (optochin and oxidase tests) are required to ensure the same quality in patient care from the distant laboratory. Nevertheless, such networking should not be considered unless there is a reorganisation of workflow, efficient communication between teams, qualified technologists and a reliable IT department and helpdesk to manage potential connectivity problems.

  4. Differential mass spectrometry: a label-free LC-MS method for finding significant differences in complex peptide and protein mixtures.

    PubMed

    Wiener, Matthew C; Sachs, Jeffrey R; Deyanova, Ekaterina G; Yates, Nathan A

    2004-10-15

    Efficiently identifying and quantifying disease- or treatment-related changes in the abundance of proteins is an important area of research for the pharmaceutical industry. Here we describe an automated, label-free method for finding differences in complex mixtures using complete LC-MS data sets, rather than subsets of extracted peaks or features. The method selectively finds statistically significant differences in the intensity of both high-abundance and low-abundance ions, accounting for the variability of measured intensities and the fact that true differences will persist in time. The method was used to compare two complex peptide mixtures with known peptide differences. This controlled experiment allowed us to assess the validity of each difference found and so to analyze the method's sensitivity and specificity. The method detects both presence versus absence and a 2-fold change in peptide concentration near the limit of detection of the instrument used, where chromatographic peaks may not be sufficiently well defined to be detected in individual samples. The method is more sensitive and gives fewer false positives than subtractive methods that ignore signal variability. Differential mass spectrometry combined with targeted MS/MS analysis of only identified differences may save both computation time and human effort compared to shotgun proteomics approaches. PMID:15481957

  5. Identification of endogenous metabolites in human sperm cells using proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Paiva, C; Amaral, A; Rodriguez, M; Canyellas, N; Correig, X; Ballescà, J L; Ramalho-Santos, J; Oliva, R

    2015-05-01

    The objective of this study was to contribute to the first comprehensive metabolomic characterization of the human sperm cell through the application of two untargeted platforms based on proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography coupled to mass spectrometry (GC-MS). Using these two complementary strategies, we were able to identify a total of 69 metabolites, of which 42 were identified using NMR, 27 using GC-MS and 4 by both techniques. The identity of some of these metabolites was further confirmed by two-dimensional (1) H-(1) H homonuclear correlation spectroscopy (COSY) and (1) H-(13) C heteronuclear single-quantum correlation (HSQC) spectroscopy. Most of the metabolites identified are reported here for the first time in mature human spermatozoa. The relationship between the metabolites identified and the previously reported sperm proteome was also explored. Interestingly, overrepresented pathways included not only the metabolism of carbohydrates, but also of lipids and lipoproteins. Of note, a large number of the metabolites identified belonged to the amino acids, peptides and analogues super class. The identification of this initial set of metabolites represents an important first step to further study their function in male gamete physiology and to explore potential reasons for dysfunction in future studies. We also demonstrate that the application of NMR and MS provides complementary results, thus constituting a promising strategy towards the completion of the human sperm cell metabolome.

  6. Gas chromatography-mass spectrometry (GC-MS) method for the determination of 16 European priority polycyclic aromatic hydrocarbons in smoked meat products and edible oils.

    PubMed

    Jira, W; Ziegenhals, K; Speer, K

    2008-06-01

    A gas chromatography-mass spectrometry (GC-MS) method was developed for the analysis of 15 polycyclic aromatic hydrocarbons (PAHs) highlighted as carcinogenic by the Scientific Committee on Food (SCF) plus benzo[c]fluorine (recommended to be analysed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in fat-containing foods such as edible oils and smoked meat products. This method includes accelerated solvent extraction (ASE) and the highly automated clean-up steps gel permeation chromatography (GPC) and solid-phase extraction (SPE). Using a VF-17ms GC column, a good separation of benzo[b]fluoranthene, benzo[j]fluoranthene and benzo[k]fluoranthene was achieved. Futhermore, the six methylchrysene isomers and the PAH compounds with a molecular weight of 302 Daltons in fat-containing foods attained a better chromatographic separation in comparison with a 5-ms column. The reliability of the analytical method for edible oils was demonstrated by the results from a proficiency test. Measurements with GC-high-resolution mass spectroscopy (HRMS) and gas chromatography-mass selective detection (GC-MSD) led to comparable results. A survey of the 16 PAHs in 22 smoked meat products showed concentrations in the range < 0.01-19 microg kg(-1). The median concentration for benzo[a]pyrene was below 0.15 microg kg(-1).

  7. Pivotal role of computers and software in mass spectrometry - SEQUEST and 20 years of tandem MS database searching.

    PubMed

    Yates, John R

    2015-11-01

    Advances in computer technology and software have driven developments in mass spectrometry over the last 50 years. Computers and software have been impactful in three areas: the automation of difficult calculations to aid interpretation, the collection of data and control of instruments, and data interpretation. As the power of computers has grown, so too has the utility and impact on mass spectrometers and their capabilities. This has been particularly evident in the use of tandem mass spectrometry data to search protein and nucleotide sequence databases to identify peptide and protein sequences. This capability has driven the development of many new approaches to study biological systems, including the use of "bottom-up shotgun proteomics" to directly analyze protein mixtures. Graphical Abstract ᅟ. PMID:26286455

  8. Pivotal role of computers and software in mass spectrometry - SEQUEST and 20 years of tandem MS database searching.

    PubMed

    Yates, John R

    2015-11-01

    Advances in computer technology and software have driven developments in mass spectrometry over the last 50 years. Computers and software have been impactful in three areas: the automation of difficult calculations to aid interpretation, the collection of data and control of instruments, and data interpretation. As the power of computers has grown, so too has the utility and impact on mass spectrometers and their capabilities. This has been particularly evident in the use of tandem mass spectrometry data to search protein and nucleotide sequence databases to identify peptide and protein sequences. This capability has driven the development of many new approaches to study biological systems, including the use of "bottom-up shotgun proteomics" to directly analyze protein mixtures. Graphical Abstract ᅟ.

  9. Pivotal Role of Computers and Software in Mass Spectrometry - SEQUEST and 20 Years of Tandem MS Database Searching

    NASA Astrophysics Data System (ADS)

    Yates, John R.

    2015-11-01

    Advances in computer technology and software have driven developments in mass spectrometry over the last 50 years. Computers and software have been impactful in three areas: the automation of difficult calculations to aid interpretation, the collection of data and control of instruments, and data interpretation. As the power of computers has grown, so too has the utility and impact on mass spectrometers and their capabilities. This has been particularly evident in the use of tandem mass spectrometry data to search protein and nucleotide sequence databases to identify peptide and protein sequences. This capability has driven the development of many new approaches to study biological systems, including the use of "bottom-up shotgun proteomics" to directly analyze protein mixtures.

  10. Detection of volatile compounds produced by microbial growth in urine by selected ion flow tube mass spectrometry (SIFT-MS).

    PubMed

    Storer, Malina K; Hibbard-Melles, Kim; Davis, Brett; Scotter, Jenny

    2011-10-01

    Selected ion flow tube-mass spectrometry has been used to measure the volatile compounds occurring in the headspace of urine samples inoculated with common urinary tract infection (UTI)-causing microbes Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Enterococcus faecalis, or Candida albicans. This technique has the potential to offer rapid and simple diagnosis of the causative agent of UTIs.

  11. Determination of the aflatoxin AFB1 from corn by direct analysis in real time-mass spectrometry (DART-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct analysis in real time (DART) ionization coupled to a high resolution mass spectrometer (MS) was used for screening of aflatoxins from a variety of surfaces and the rapid quantitative analysis of a common form of aflatoxin, AFB1, extracted from corn. Sample preparation procedure and instrument...

  12. Analysis of the aflatoxin AFB1 from corn by direct analysis in real time - mass spectrometry (DART-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct analysis in real time (DART) ionization coupled to a high resolution mass spectrometer (MS) was used for screening of aflatoxins from a variety of surfaces and the rapid quantitative analysis of aflatoxins extracted from corn. Sample preparation procedure and instrument parameter settings wer...

  13. Determination of the aflatoxin AFB1 from corn by direct analysis in real time-mass spectrometry (DART-MS).

    PubMed

    Busman, Mark; Liu, Jihong; Zhong, Hongjian; Bobell, John R; Maragos, Chris M

    2014-01-01

    Direct analysis in real time (DART) ionisation coupled to a high-resolution mass spectrometer (MS) was used for screening of aflatoxins from a variety of surfaces and the rapid quantitative analysis of a common form of aflatoxin, AFB1, extracted from corn. Sample preparation procedure and instrument parameter settings were optimised to obtain sensitive and accurate determination of aflatoxin AFB1. 84:16 acetonitrile water extracts of corn were analysed by DART-MS. The lowest calibration level (LCL) for aflatoxin AFB1 was 4 μg kg⁻¹. Quantitative analysis was performed with the use of matrix-matched standards employing the ¹³C-labelled internal standard for AFB1. DART-MS of spiked corn extracts gave linear response in the range 4-1000 μg kg⁻¹. Good recoveries (94-110%) and repeatabilities (RSD = 0.7-6.9%) were obtained at spiking levels of 20 and 100 μg kg⁻¹ with the use of an isotope dilution technique. Trueness of data obtained for AFB1 in maize by DART-MS was demonstrated by analysis of corn certified reference materials. PMID:24588621

  14. 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.

  15. Simultaneous Determination of 16 Nucleosides and Nucleobases in Euryale ferox Salisb. by Liquid Chromatography Coupled with Electro Spray Ionization Tandem Triple Quadrupole Mass Spectrometry (HPLC-ESI-TQ-MS/MS) in Multiple Reaction Monitoring (MRM) Mode.

    PubMed

    Wang, Hong; Wu, Qinan; Wu, Chengying; Jiang, Zheng

    2015-09-01

    In this study, a simple, rapid, efficient analytical method was established for the qualification and quantification of 16 nucleosides and nucleobases in Euryale ferox Salisb. by using liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-TQ-MS/MS) in multiple-reaction monitoring (MRM) mode. Ideal separation of 16 target compounds was achieved on Xbridge Amide HILIC column (4.6 × 150 mm, 3.5 μm) with gradient elution in 11 min by optimized conditions. Variations of nucleosides and nucleobase in samples from different cultivation regions ranging from 190.50 to 1594.30 μg/g were obvious. The total nucleoside contents were higher than total nucleobases, especially in the compositions of guanosine, cytidine and 2'-deoxyguanosine. Samples 1-18 with dense thorns were better characters than samples 19-26 without thorns in terms of nucleosides and nucleobases concentrations in general. The limits of detection (LODs) and quantification (LOQs) for 16 analytical substances were investigated to be 0.11-6.33 ng/mL and 0.35-21.1 ng/mL, respectively. And the method was first applied to large aquatic plants with good linearity, precision, repeatability and accuracy. All present information provided a scientific and rational reference for quality assessment and control of Euryale ferox Salisb.

  16. Simultaneous Determination of 16 Nucleosides and Nucleobases in Euryale ferox Salisb. by Liquid Chromatography Coupled with Electro Spray Ionization Tandem Triple Quadrupole Mass Spectrometry (HPLC-ESI-TQ-MS/MS) in Multiple Reaction Monitoring (MRM) Mode.

    PubMed

    Wang, Hong; Wu, Qinan; Wu, Chengying; Jiang, Zheng

    2015-09-01

    In this study, a simple, rapid, efficient analytical method was established for the qualification and quantification of 16 nucleosides and nucleobases in Euryale ferox Salisb. by using liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-TQ-MS/MS) in multiple-reaction monitoring (MRM) mode. Ideal separation of 16 target compounds was achieved on Xbridge Amide HILIC column (4.6 × 150 mm, 3.5 μm) with gradient elution in 11 min by optimized conditions. Variations of nucleosides and nucleobase in samples from different cultivation regions ranging from 190.50 to 1594.30 μg/g were obvious. The total nucleoside contents were higher than total nucleobases, especially in the compositions of guanosine, cytidine and 2'-deoxyguanosine. Samples 1-18 with dense thorns were better characters than samples 19-26 without thorns in terms of nucleosides and nucleobases concentrations in general. The limits of detection (LODs) and quantification (LOQs) for 16 analytical substances were investigated to be 0.11-6.33 ng/mL and 0.35-21.1 ng/mL, respectively. And the method was first applied to large aquatic plants with good linearity, precision, repeatability and accuracy. All present information provided a scientific and rational reference for quality assessment and control of Euryale ferox Salisb. PMID:25947362

  17. Applicability of Gas Chromatography (GC) Coupled to Triple-Quadrupole (QqQ) Tandem Mass Spectrometry (MS/MS) for Polybrominated Diphenyl Ether (PBDE) and Emerging Brominated Flame Retardant (BFR) Determinations in Functional Foods Enriched in Omega-3.

    PubMed

    García-Bermejo, Ángel; Mohr, Susana; Herrero, Laura; González, María-José; Gómara, Belén

    2016-09-28

    This paper reports on the optimization, characterization, and applicability of gas chromatography coupled to triple-quadrupole tandem mass spectrometry (GC-QqQ(MS/MS)) for the determination of 14 polybrominated diphenylethers (PBDEs) and 2 emerging brominated flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), in functional food samples. The method showed satisfactory precision and linearity with instrumental limits of detection (iLODs) ranging from 0.12 to 7.1 pg, for tri- to octa-BDEs and BTBPE, and equal to 51 and 20 pg for BDE-209 and DBDPE, respectively. The highest ΣBFR concentrations were found in fish oil supplements (924 pg/g fresh weight, fw), followed by biscuits (90 pg/g fw), vegetable oil supplements (46 pg/g fw), chicken eggs (45 pg/g fw), cow's milk (7.7 pg/g fw), and soy products (1.6 pg/g fw). BDE-47, BDE-99, and DBDPE were the most abundant compounds. Foodstuffs enriched with omega-3 presented concentrations similar to or even lower than those of conventional foods commercialized in Spain since 2000. PMID:27600263

  18. Applicability of Gas Chromatography (GC) Coupled to Triple-Quadrupole (QqQ) Tandem Mass Spectrometry (MS/MS) for Polybrominated Diphenyl Ether (PBDE) and Emerging Brominated Flame Retardant (BFR) Determinations in Functional Foods Enriched in Omega-3.

    PubMed

    García-Bermejo, Ángel; Mohr, Susana; Herrero, Laura; González, María-José; Gómara, Belén

    2016-09-28

    This paper reports on the optimization, characterization, and applicability of gas chromatography coupled to triple-quadrupole tandem mass spectrometry (GC-QqQ(MS/MS)) for the determination of 14 polybrominated diphenylethers (PBDEs) and 2 emerging brominated flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), in functional food samples. The method showed satisfactory precision and linearity with instrumental limits of detection (iLODs) ranging from 0.12 to 7.1 pg, for tri- to octa-BDEs and BTBPE, and equal to 51 and 20 pg for BDE-209 and DBDPE, respectively. The highest ΣBFR concentrations were found in fish oil supplements (924 pg/g fresh weight, fw), followed by biscuits (90 pg/g fw), vegetable oil supplements (46 pg/g fw), chicken eggs (45 pg/g fw), cow's milk (7.7 pg/g fw), and soy products (1.6 pg/g fw). BDE-47, BDE-99, and DBDPE were the most abundant compounds. Foodstuffs enriched with omega-3 presented concentrations similar to or even lower than those of conventional foods commercialized in Spain since 2000.

  19. The performance and the characterization of laser ablation aerosol particle time-of-flight mass spectrometry (LAAP-ToF-MS)

    NASA Astrophysics Data System (ADS)

    Gemayel, Rachel; Hellebust, Stig; Temime-Roussel, Brice; Hayeck, Nathalie; Van Elteren, Johannes T.; Wortham, Henri; Gligorovski, Sasho

    2016-05-01

    Hyphenated laser ablation-mass spectrometry instruments have been recognized as useful analytical tools for the detection and chemical characterization of aerosol particles. Here we describe the performances of a laser ablation aerosol particle time-of-flight mass spectrometer (LAAP-ToF-MS) which was designed for aerodynamic particle sizing using two 405 nm scattering lasers and characterization of the chemical composition of single aerosol particle via ablation/ionization by a 193 nm excimer laser and detection in a bipolar time-of-flight mass spectrometer with a mass resolving power of m/Δm > 600.

    We describe a laboratory based optimization strategy for the development of an analytical methodology for characterization of atmospheric particles using the LAAP-ToF-MS instrument in combination with a particle generator, a differential mobility analyzer and an optical particle counter. We investigated the influence of particle number concentration, particle size and particle composition on the detection efficiency. The detection efficiency is a product of the scattering efficiency of the laser diodes and the ionization efficiency or hit rate of the excimer laser. The scattering efficiency was found to vary between 0.6 and 1.9 % with an average of 1.1 %; the relative standard deviation (RSD) was 17.0 %. The hit rate exhibited good repeatability with an average value of 63 % and an RSD of 18 %. In addition to laboratory tests, the LAAP-ToF-MS was used to sample ambient air during a period of 6 days at the campus of Aix-Marseille University, situated in the city center of Marseille, France. The optimized LAAP-ToF-MS methodology enables high temporal resolution measurements of the chemical composition of ambient particles, provides new insights into environmental science, and a new investigative tool for atmospheric chemistry and physics, aerosol science and health impact studies.

  20. Characterization of Nα-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MS(n)): effect of protecting group on fragmentation of dipeptides.

    PubMed

    Ramesh, M; Raju, B; Srinivas, R; Sureshbabu, V V; Vishwanatha, T M; Hemantha, H P

    2011-07-30

    A series of positional isomeric pairs of Fmoc-protected dipeptides, Fmoc-Gly-Xxx-OY/Fmoc-Xxx-Gly-OY (Xxx=Ala, Val, Leu, Phe) and Fmoc-Ala-Xxx-OY/Fmoc-Xxx-Ala-OY (Xxx=Leu, Phe) (Fmoc=[(9-fluorenylmethyl)oxy]carbonyl) and Y=CH(3)/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS(n)). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y(1)(+) and/or a(1)(+) ions, the protonated Fmoc-Xxx-Gly-OY, Fmoc-Ala-Xxx-OY and Fmoc-Xxx-Ala-OY yield significant b(1)(+) ions. These ions are formed, presumably with stable protonated aziridinone structures. However, the peptides with Gly- at the N-terminus do not form b(1)(+) ions. The [M+H](+) ions of all the peptides undergo a McLafferty-type rearrangement followed by loss of CO(2) to form [M+H-Fmoc+H](+). The MS(3) collision-induced dissociation (CID) of these ions helps distinguish the pairs of isomeric dipeptides studied in this work. Further, negative ion MS(3) CID has also been found to be useful for differentiating these isomeric peptide acids. The MS(3) of [M-H-Fmoc+H](-) of isomeric peptide acids produce c(1)(-), z(1)(-) and y(1)(-) ions. Thus the present study of Fmoc-protected peptides provides additional information on mass spectral characterization of the dipeptides and distinguishes the positional isomers.

  1. Structural calculations and experimental detection of small Ga mS n clusters using time-of-flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    BelBruno, J. J.; Sanville, E.; Burnin, A.; Muhangi, A. K.; Malyutin, A.

    2009-08-01

    Ga mS n clusters were generated by laser ablation of a solid sample of Ga 2S 3. The resulting molecules were analyzed in a time-of-flight mass spectrometer. In addition to atomic species, the spectra exhibited evidence for the existence of GaS3+, GaS4+, GaS5+, and GaS6+ clusters. The potential neutral and cationic structures of the observed Ga mS n clusters were computationally investigated using a density-functional approach. Reference is made to the kinetic pathways required for production of clusters from the starting point of the stoichiometric molecule or molecular ion. Cluster atomization enthalpies are compared with bulk values from the literature.

  2. Determination of volatile aroma compounds of Ganoderma lucidum by gas chromatography mass spectrometry (HS-GC/MS).

    PubMed

    Taşkın, Hatıra; Kafkas, Ebru; Çakıroğlu, Özgün; Büyükalaca, Saadet

    2013-01-01

    This study was conducted at Horticulture Department of Cukurova University, Adana, Turkey during 2010-2011. Fresh sample of Ganoderma lucidum collected from Mersin province of Turkey was used as material. Volatile aroma compounds were performed by Headspace Gas Chromatography (HS-GC/MS). Alcohols, aldehydes, acids, phenol, L-Alanine, d-Alanine, 3Methyl, 2-Butanamine, 2-Propanamine were determined. 1-Octen-3-ol (Alcohol) and 3-methyl butanal (Aldehyde) were identified as major aroma compounds.

  3. Sequence Verification of Oligonucleotides Containing Multiple Arylamine Modifications by Enzymatic Digestion and Liquid Chromatography Mass Spectrometry (LC/MS)

    PubMed Central

    Gao, Lan; Zhang, Li; Cho, Bongsup P.; Chiarelli, M. Paul

    2010-01-01

    An analytical method for the structure differentiation of arylamine modified oligonucleotides (ODNs) using on-line LC/MS analysis of raw exonuclease digests is described. Six different dodeca ODNs derived from the reaction of N-acetoxy-N-(trifluoroacetyl)-2-aminofluorene with the dodeca oligonucleotide 5′-CTCGGCGCCATC-3′ are isolated and sequenced with this LC/MS method using 3′- and 5′-exonucleases. When the three products modified by a single aminofluorene (AF) are subjected to 3′-exonuclease digestion, the exonuclease will cleave a modified nucleotide but when di-AF modified ODNs are analyzed the 3′-exonuclease ceases to cleave nucleotides when the first modification is exposed at the 3′-terminus. Small abundances of ODN fragments formed by the cleavage of an AF-modified nucleotide were observed when two of the three di-AF modified ODNs were subjected to 5′-exonuclease digestion. The results of the 5′-exonuclease studies of the three di-AF modified ODNs suggest that as the number of unmodified bases between two modifications in an ODN sequence increases, the easier it becomes to sequence beyond the modification closest to the 5′-terminus. The results of this study indicate that the LC/MS method described here would be useful in sequencing ODNs modified by multiple arylamines to be used as templates for site-specific mutagenesis studies. PMID:18524623

  4. Microwave distillation followed by headspace single drop microextraction coupled to gas chromatography-mass spectrometry (GC-MS) for fast analysis of volatile components of Echinophora platyloba DC.

    PubMed

    Gholivand, Mohammad Bagher; Abolghasemi, Mir Mahdi; Piryaei, Marzieh; Maassoumi, Sayed Mohammad; Papzan, Abdolhamid

    2013-05-01

    To avoid the traditional and time consuming hydrodistillation, the analyses of volatile components in aerial parts of Echinophora platyloba DC was carried out by a simple microwave distillation followed by headspace single drop microextraction (MD-HS-SDME) coupled to gas chromatography-mass spectrometry (GC-MS). The headspace volatile compounds were collected after irradiation using a single drop of n-heptadecan. The extraction conditions were optimised using the relative peak areas as index. The chemical composition of the MD-HS-SDME extracts was confirmed according to their retention indexes and mass spectra. Fifty-three components were extracted and identified by using the MD-HS-SDME method. E-β-ocimene (53.81%), R-D-decalactone (12.75%), α-pinene (6.43%), n-heptanol (6.27%), β-phellanderne (2.70%) and linalool (1.89%) were the major constituents.

  5. Microwave distillation followed by headspace single drop microextraction coupled to gas chromatography-mass spectrometry (GC-MS) for fast analysis of volatile components of Echinophora platyloba DC.

    PubMed

    Gholivand, Mohammad Bagher; Abolghasemi, Mir Mahdi; Piryaei, Marzieh; Maassoumi, Sayed Mohammad; Papzan, Abdolhamid

    2013-05-01

    To avoid the traditional and time consuming hydrodistillation, the analyses of volatile components in aerial parts of Echinophora platyloba DC was carried out by a simple microwave distillation followed by headspace single drop microextraction (MD-HS-SDME) coupled to gas chromatography-mass spectrometry (GC-MS). The headspace volatile compounds were collected after irradiation using a single drop of n-heptadecan. The extraction conditions were optimised using the relative peak areas as index. The chemical composition of the MD-HS-SDME extracts was confirmed according to their retention indexes and mass spectra. Fifty-three components were extracted and identified by using the MD-HS-SDME method. E-β-ocimene (53.81%), R-D-decalactone (12.75%), α-pinene (6.43%), n-heptanol (6.27%), β-phellanderne (2.70%) and linalool (1.89%) were the major constituents. PMID:23265484

  6. The use of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of toxic and essential elements in different types of food samples

    NASA Astrophysics Data System (ADS)

    Voica, C.; Dehelean, A.; Kovacs, M. H.

    2012-02-01

    Food is the primary source of essential elements for humans and it is an important source of exposure to toxic elements. In this context, levels of essential and toxic elements must be determined routinely in consumed food products. The content of trace elements (As, Pb, Cu, Cd, Zn, Sn, Hg) in different types of food samples (e.g. rice, bread, sugar, cheese, milk, butter, wheat, coffee, chocolate, biscuits pasta, etc.) was determined, using inductively coupled plasma mass spectrometry (ICP-MS). Trace element contents in some foods were higher than maximum permissible levels of toxic metals in human food (Cd in bread, Zn in cheese, Cu in coffee, Hg in carrots and peppers).

  7. A lectin-coupled, targeted proteomic mass spectrometry (MRM MS) platform for identification of multiple liver cancer biomarkers in human plasma.

    PubMed

    Ahn, Yeong Hee; Shin, Park Min; Oh, Na Ree; Park, Gun Wook; Kim, Hoguen; Yoo, Jong Shin

    2012-09-18

    Aberrantly glycosylated proteins related to liver cancer progression were captured with specific lectin and identified from human plasma by multiple reaction monitoring (MRM) mass spectrometry as multiple biomarkers for hepatocellular carcinoma (HCC). The lectin fractionation for fucosylated protein glycoforms in human plasma was conducted with a fucose-specific aleuria aurantia lectin (AAL). Following tryptic digestion of the lectin-captured fraction, plasma samples from 30 control cases (including 10 healthy, 10 hepatitis B virus [HBV], and 10 cirrhosis cases) and 10 HCC cases were quantitatively analyzed by MRM to identify which glycoproteins are viable HCC biomarkers. A1AG1, AACT, A1AT, and CERU were found to be potent biomarkers to differentiate HCC plasma from control plasmas. The AUROC generated independently from these four biomarker candidates ranged from 0.73 to 0.92. However, the lectin-coupled MRM assay with multiple combinations of biomarker candidates is superior statistically to those generated from the individual candidates with AUROC more than 0.95, which can be an alternative to the immunoassay inevitably requiring tedious development of multiple antibodies against biomarker candidates to be verified. Eventually the lectin-coupled, targeted proteomic mass spectrometry (MRM MS) platform was found to be efficient to identify multiple biomarkers from human plasma according to cancer progression.

  8. Online measurement of biogenic organic acids in the boreal forest using atmospheric pressure chemical ionization mass spectrometry (APCI-MS)

    NASA Astrophysics Data System (ADS)

    Vogel, A. L.; Brüggemann, M.; ńijälä, M.; Ehn, M.; Junninen, H.; Corrigan, A. L.; Petäjä, T.; Worsnop, D. R.; Russell, L. M.; Kulmala, M.; Williams, J.; Hoffmann, T.

    2012-04-01

    Emission of biogenic volatile organic compounds (BVOCs) by vegetation in the boreal forest and their subsequent atmospheric oxidation leads to the formation of secondary organic aerosol (SOA) which has important impacts on climate and human health. Oxidation of BVOCs produces a variety of mostly unidentified species in oxygenated organic aerosol (OOA). Presently aerosol mass spectrometers (AMS) are able to determine quantitative information about the relative oxygen to carbon content of organic aerosols and thereby reveal the photochemical age and volatility of organic aerosol by distinguishing between low volatile oxygenated organic aerosol (LV-OOA), semivolatile oxygenated organic aerosol (SV-OOA) and hydrocarbon like organic aerosol (HOA)[1]. However, the AMS can usually not be used to measure and quantify single organic compounds such as individual biogenic organic marker compounds. Here we show the results of online measurements of gas and particle phase biogenic acids during HUMPPA-COPEC 2010 at Hyytiälä, Finland. This was achieved by coupling a self built miniature Versatile Aerosol Concentration Enrichment System (mVACES) as described by Geller et al. [2] with an Atmospheric Pressure Chemical Ionization Ion Trap Mass Spectrometer (APCI IT MS; Hoffmann et al., [3]). The benefits of the on-line APCI-MS are soft ionization with little fragmentation compared to AMS, high measurement frequency and less sampling artifacts than in the common procedure of taking filter samples, extraction and detection with LC-MS. Furthermore, the ion trap of the instrument allows MS/MS experiments to be performed by isolation of single m/z ratios of selected molecular species. By subsequent addition of energy, the trapped ions form characteristic fragments which enable structural insight on the molecular level. Comparison of APCI-MS data to AMS data, acquired with a C-ToF-AMS [4], revealed a good correlation coefficient for total organics and sulphate. Furthermore, data show

  9. Elucidating the higher-order structure of biopolymers by structural probing and mass spectrometry: MS3D

    PubMed Central

    Fabris, Daniele; Yu, Eizadora T.

    2010-01-01

    Chemical probing represents a very versatile alternative for studying the structure and dynamics of substrates that are intractable by established high-resolution techniques. The implementation of MS-based strategies for the characterization of probing products has not only extended the range of applicability to virtually all types of biopolymers, but has also paved the way for the introduction of new reagents that would not have been viable with traditional analytical platforms. As the availability of probing data is steadily increasing on the wings of the development of dedicated interpretation aids, powerful computational approaches have been explored to enable the effective utilization of such information to generate valid molecular models. This combination of factors has contributed to making the possibility of obtaining actual 3D structures by MS-based technologies (MS3D) a reality. Although approaches for achieving structure determination of unknown substrates or assessing the dynamics of known structures may share similar reagents and development trajectories, they clearly involve distinctive experimental strategies, analytical concerns, and interpretation paradigms. This Perspective offers a commentary on methods aimed at obtaining distance constraints for the modeling of full-fledged structures, while highlighting common elements, salient distinctions, and complementary capabilities exhibited by methods employed in dynamics studies. We discuss critical factors to be addressed for completing effective structural determinations and expose possible pitfalls of chemical methods. We survey programs developed for facilitating the interpretation of experimental data and discuss possible computational strategies for translating sparse spatial constraints into all-atom models. Examples are provided to illustrate how the concerted application of very diverse probing techniques can lead to the solution of actual biological substrates. PMID:20648672

  10. Determination of bromine and tin compounds in plastics using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

    PubMed

    İzgi, Belgin; Kayar, Murat

    2015-07-01

    The polybrominated flame retardants and organotin compounds were screened in terms of bromine and tin content using laser ablation inductively coupled plasma mass spectrometry in plastics. The calibration standards were prepared using the fused-disk technique, and all samples were investigated under optimal conditions. Using a central composite experimental design, laser parameters, laser energy, pulse rate, scan rate and spot size were identified. The detection limits of the method were 1000 mgkg(-1) and 1600 mgkg(-1) for bromide and tin, whereas the relative standard deviation (%) values of the analysis were 9% and 6% (n=3) for ERM EC681k with 770 ± 70 mgkg(-1) Br and 86 ± 6 mgkg(-1) Sn respectively, and 106-115% of Br and 102-104% of Sn were observed for the tetrabromobisphenol A and butyltin trichloride spike plastics, respectively.

  11. Simultaneous determination of chlorpyrifos and 3,5,6-trichloro-2-pyridinol in duck muscle by modified QuEChERS coupled to gas chromatography tandem mass spectrometry (GC-MS/MS).

    PubMed

    Li, Rui; He, Liang; Zhou, Ting; Ji, Xiaofeng; Qian, Mingrong; Zhou, Yu; Wang, Qiang

    2014-05-01

    A rapid, specific, and sensitive method based on modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) coupled to gas chromatography tandem mass spectrometry (GC-MS/MS) was developed and validated for simultaneous determination of chlorpyrifos (CP) and its metabolite 3,5,6-trichloro-2-pyridinol (TCP) in duck muscle. The residues of CP and TCP were extracted by acidified acetonitrile. The fat layer of the extract was removed under -20 °C, then the organic layer was evaporated. The analytes were derivatized by N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) and cleaned up by a mixture of 150 mg MgSO4, 25 mg graphitized carbon black (GCB), and 50 mg N-propylethylenediamine (PSA) to remove interference. The final extract was analyzed by GC-MS/MS. Recovery values at the spiking concentrations ranged from 86.2 to 92.3 % for CP and from 74.8 to 81.8 % for TCP, with relative standard deviations (RSDs) lower than 9.5 and 12.3, respectively. The correlation coefficients of CP (from 2 to 2,000 μg/kg) and TCP (from 1 to 1,000 μg/kg) were equal to or higher than 0.998. The limits of detection (LODs) were 0.3 and 0.15 μg/kg, and the limits of quantification (LOQs) were 1.0 and 0.5 μg/kg for CP and TCP in duck muscle, respectively. The average intra- and inter-day accuracy ranged from 84.6 to 91.2 % for CP and 75.6 to 82.3 % for TCP, and the intra- and inter-day precisions were from 5.8 to 8.2 % for CP and 6.5 to 11.9 % for TCP. Furthermore, the CP and TCP residues in duck muscle samples were detected for dietary risk assessment using the validated method. PMID:24691719

  12. Online solid phase extraction liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) method for the determination of sucralose in reclaimed and drinking waters and its photo degradation in natural waters from South Florida

    PubMed Central

    2013-01-01

    Background Sucralose has gained popularity as a low calorie artificial sweetener worldwide. Due to its high stability and persistence, sucralose has shown widespread occurrence in environmental waters, at concentrations that could reach up to several μg/L. Previous studies have used time consuming sample preparation methods (offline solid phase extraction/derivatization) or methods with rather high detection limits (direct injection) for sucralose analysis. This study described a faster and sensitive analytical method for the determination of sucralose in environmental samples. Results An online SPE-LC–MS/MS method was developed, being capable to quantify sucralose in 12 minutes using only 10 mL of sample, with method detection limits (MDLs) of 4.5 ng/L, 8.5 ng/L and 45 ng/L for deionized water, drinking and reclaimed waters (1:10 diluted with deionized water), respectively. Sucralose was detected in 82% of the reclaimed water samples at concentrations reaching up to 18 μg/L. The monthly average for a period of one year was 9.1 ± 2.9 μg/L. The calculated mass loads per capita of sucralose discharged through WWTP effluents based on the concentrations detected in wastewaters in the U. S. is 5.0 mg/day/person. As expected, the concentrations observed in drinking water were much lower but still relevant reaching as high as 465 ng/L. In order to evaluate the stability of sucralose, photodegradation experiments were performed in natural waters. Significant photodegradation of sucralose was observed only in freshwater at 254 nm. Minimal degradation (<20%) was observed for all matrices under more natural conditions (350 nm or solar simulator). The only photolysis product of sucralose identified by high resolution mass spectrometry was a de-chlorinated molecule at m/z 362.0535, with molecular formula C12H20Cl2O8. Conclusions Online SPE LC-APCI/MS/MS developed in the study was applied to more than 100 environmental samples. Sucralose was frequently

  13. Data from mass spectrometry, NMR spectra, GC-MS of fatty acid esters produced by Lasiodiplodia theobromae.

    PubMed

    Uranga, Carla C; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D; Hernández-Martínez, Rufina

    2016-09-01

    The data described herein is related to the article with the title "Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings" C.C. Uranga, J. Beld, A. Mrse, I. Cordova-Guerrero, M.D. Burkart, R. Hernandez-Martinez (2016) [1]. Data includes nuclear magnetic resonance spectroscopy and GC-MS data used for the identification and characterization of fatty acid esters produced by L. theobromae. GC-MS traces are also shown for incubations in defined substrate, consisting in Vogel׳s salts supplemented with either 5% grapeseed oil or 5% glucose, the two combined, or 5% fructose. Traces for incubations in the combination of 5% grapeseed oil and 5% glucose for different fungal species are also included. Images of mycelium morphology when grown in 5% glucose with or without 5% grapeseed oil are shown due to the stark difference in mycelial pigmentation in the presence of triglycerides. High concentration gradient data for the plant model Nicotiana tabacum germinated in ethyl stearate (SAEE) and ethyl linoleate (LAEE) is included to show the transition between growth inhibition and growth induction in N. tabacum by these compounds.

  14. Data from mass spectrometry, NMR spectra, GC-MS of fatty acid esters produced by Lasiodiplodia theobromae.

    PubMed

    Uranga, Carla C; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D; Hernández-Martínez, Rufina

    2016-09-01

    The data described herein is related to the article with the title "Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings" C.C. Uranga, J. Beld, A. Mrse, I. Cordova-Guerrero, M.D. Burkart, R. Hernandez-Martinez (2016) [1]. Data includes nuclear magnetic resonance spectroscopy and GC-MS data used for the identification and characterization of fatty acid esters produced by L. theobromae. GC-MS traces are also shown for incubations in defined substrate, consisting in Vogel׳s salts supplemented with either 5% grapeseed oil or 5% glucose, the two combined, or 5% fructose. Traces for incubations in the combination of 5% grapeseed oil and 5% glucose for different fungal species are also included. Images of mycelium morphology when grown in 5% glucose with or without 5% grapeseed oil are shown due to the stark difference in mycelial pigmentation in the presence of triglycerides. High concentration gradient data for the plant model Nicotiana tabacum germinated in ethyl stearate (SAEE) and ethyl linoleate (LAEE) is included to show the transition between growth inhibition and growth induction in N. tabacum by these compounds. PMID:27274528

  15. Nuclear Magnetic Resonance (NMR), Infrared (IR) and Mass Spectrometry (MS) study of keto-enol tautomerism of isobenzofuran-1(3H)-one derivatives

    NASA Astrophysics Data System (ADS)

    Pires, Diego Arantes Teixeira; Pereira, Wagner Luiz; Teixeira, Róbson Ricardo; Figueroa-Villar, José Daniel; Nascimento, Claudia Jorge do

    2016-06-01

    The keto-enol tautomerism of 3-(2-hydroxy-4,4-dimethyl-6-oxo-cyclohexen-1-yl)isobenzofuran-1(3H-one (1), 3-(2-hydroxy-6-oxocyclohex-1-enyl)isobenzofuran-1(3H)-one (2), 3-(2-hydroxy-4-methyl-6-oxocyclohex-1-enyl)isobenzofuran-1(3H)-one (3), 3-(2-hydroxy-5-oxocyclopent-1-enyl)isobenzofuran-1(3H)-one (4) and 2-(3-oxo-1,3-dihydroisobenzofuran-1-yl)-1H-indene-1,3(2H)-dione (5) were investigated. We noticed that for compounds 1 to 4 only the enol form is observed in solid, in solution or in the gas phase. Their tautomeric equilibria are not affected by the solvent, temperature or physical state. Compound 5 was observed in its keto form in solution (NMR) and solid state (IR). The enol species of 5 was also observed upon Mass Spectrometry analysis. These findings were supported by NMR, IR, MS/MS and molecular modeling analyses.

  16. Determination of different recreational drugs in sweat by headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME GC/MS): Application to drugged drivers.

    PubMed

    Gentili, Stefano; Mortali, Claudia; Mastrobattista, Luisa; Berretta, Paolo; Zaami, Simona

    2016-09-10

    A procedure based on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC/MS) has been developed for the determination of most commonly used drugs of abuse in sweat of drivers stopped during roadside controls. DrugWipe 5A sweat screening device was used to collect sweat by a specific pad rubbed gently over forehead skin surface. The procedure involved an acid hydrolysis, a HS-SPME extraction for drugs of abuse but Δ(9)-tetrahydrocannabinol, which was directly extracted in alkaline medium HS-SPME conditions, a GC separation of analytes by a capillary column and MS detection by electron impact ionisation. The method was linear from the limit of quantification (LOQ) to 50ng drug per pad (r(2)≥0.99), with an intra- and inter-assay precision and accuracy always less than 15% and an analytical recovery between 95.1% and 102.8%, depending on the considered analyte. Using the validated method, sweat from 60 apparently intoxicated drivers were found positive to one or more drugs of abuse, showing sweat patches testing as a viable economic and simple alternative to conventional (blood and/or urine) and non conventional (oral fluid) testing of drugs of abuse in drugged drivers. PMID:27442890

  17. Mobile selected ion flow tube mass spectrometry (SIFT-MS) devices and their use for pollution exposure monitoring in breath and ambient air-pilot study.

    PubMed

    Storer, Malina; Salmond, Jennifer; Dirks, Kim N; Kingham, Simon; Epton, Michael

    2014-09-01

    Studies of health effects of air pollution exposure are limited by inability to accurately determine dose and exposure of air pollution in field trials. We explored the feasibility of using a mobile selected ion flow tube mass spectrometry (SIFT-MS) device, housed in a van, to determine ambient air and breath levels of benzene, xylene and toluene following exercise in areas of high motor vehicle traffic. The breath toluene, xylene and benzene concentration of healthy subjects were measured before and after exercising close to a busy road. The concentration of the volatile organic compounds (VOCs), in ambient air were also analysed in real time. Exercise close to traffic pollution is associated with a two-fold increase in breath VOCs (benzene, xylene and toluene) with levels returning to baseline within 20 min. This effect is not seen when exercising away from traffic pollution sources. Situating the testing device 50 m from the road reduced any confounding due to VOCs in the inspired air prior to the breath testing manoeuvre itself. Real-time field testing for air pollution exposure is possible using a mobile SIFT-MS device. This device is suitable for exploring exposure and dose relationships in a number of large scale field test scenarios.

  18. 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. PMID:24272386

  19. Accuracy profile validation of a new method for carbon monoxide measurement in the human blood using headspace-gas chromatography-mass spectrometry (HS-GC-MS).

    PubMed

    Varlet, V; De Croutte, E Lagroy; Augsburger, M; Mangin, P

    2012-01-01

    The aim of our study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable for the routine determination of blood CO concentration in forensic toxicology laboratories. The main drawback of the GC/MS methods discussed in literature for CO measurement is the absence of a specific CO internal standard necessary for performing quantification. Even if stable isotope of CO is commercially available in the gaseous state, it is essential to develop a safer method to limit the manipulation of gaseous CO and to precisely control the injected amount of CO for spiking and calibration. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in a vial in situ, an internal labeled standard gas ((13)CO) formed by the reaction of labeled formic acid formic acid (H(13)COOH) with sulfuric acid. As sulfuric acid can also be employed to liberate the CO reagent from whole blood, the procedure allows for the liberation of CO simultaneously with the generation of (13)CO. This method allows for precise measurement of blood CO concentrations from a small amount of blood (10 μL). Finally, this method was applied to measure the CO concentration of intoxicated human blood samples from autopsies.

  20. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics for comparison of caffeinated and decaffeinated coffee and its implications for Alzheimer's disease.

    PubMed

    Chang, Kai Lun; Ho, Paul C

    2014-01-01

    Findings from epidemiology, preclinical and clinical studies indicate that consumption of coffee could have beneficial effects against dementia and Alzheimer's disease (AD). The benefits appear to come from caffeinated coffee, but not decaffeinated coffee or pure caffeine itself. Therefore, the objective of this study was to use metabolomics approach to delineate the discriminant metabolites between caffeinated and decaffeinated coffee, which could have contributed to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed distinct separation between the two types of coffee (cumulative Q(2) = 0.998). A total of 69 discriminant metabolites were identified based on the OPLS-DA model, with 37 and 32 metabolites detected to be higher in caffeinated and decaffeinated coffee, respectively. These metabolites include several benzoate and cinnamate-derived phenolic compounds, organic acids, sugar, fatty acids, and amino acids. Our study successfully established GC-TOF-MS based metabolomics approach as a highly robust tool in discriminant analysis between caffeinated and decaffeinated coffee samples. Discriminant metabolites identified in this study are biologically relevant and provide valuable insights into therapeutic research of coffee against AD. Our data also hint at possible involvement of gut microbial metabolism to enhance therapeutic potential of coffee components, which represents an interesting area for future research. PMID:25098597

  1. Fast screening and secure confirmation of milk powder adulteration with maltodextrin via electrospray ionization-mass spectrometry [ESI(+)-MS] and selective enzymatic hydrolysis.

    PubMed

    Sanvido, Gustavo B; Garcia, Jerusa S; Corilo, Yuri E; Vaz, Boniek G; Zacca, Jorge J; Cosso, Ricardo G; Eberlin, Marcos N; Peter, Martin G

    2010-09-01

    Direct-infusion electrospray ionization-mass spectrometry [ESI(+)-MS] of several milk powder samples, confiscated by the Brazilian Federal Police, showed ions accounting for sodiated and potassiated molecules of disaccharides (m/z 365 and 381) as well as trisaccharides (m/z 527 and 543), whereas monosaccharide ions were not detected. The trisaccharide ions were not detected in samples of genuine milk powder, raising the suspicion that their presence indicates adulteration by the addition of maltodextrin. In control samples, maltose and maltotriose were hydrolyzed by alpha-glucosidase and not beta-galactosidase, whereas lactose was resistant to alpha-glucosidase but was hydrolyzed with beta-galactosidase. Samples suspected of being adulterated behaved in the same fashion, confirming the presence of maltose and maltotriose or maltodextrin. Direct-infusion ESI-MS is shown therefore to provide rapid screening of milk powder for adulteration with maltodextrin, whereas its combination with selective enzymatic hydrolysis provides highly reliable confirmation for unambiguous results.

  2. Using non-targeted direct analysis in real time-mass spectrometry (DART-MS) to discriminate seeds based on endogenous or exogenous chemicals.

    PubMed

    Subbaraj, Arvind K; Barrett, Brent A; Wakelin, Steve A; Fraser, Karl

    2015-10-01

    Forage seeds are a highly traded agricultural commodity, and therefore, quality control and assurance is high priority. In this study, we have used direct analysis in real time-mass spectrometry (DART-MS) as a tool to discriminate forage seeds based on their non-targeted chemical profiles. In the first experiment, two lots of perennial ryegrass (Lolium perenne L.) seed were discriminated based on exogenous residues of N-(3, 4-dichlorophenyl)-N,N-dimethylurea (Diuron(TM)), a herbicide. In a separate experiment, washed and unwashed seeds of the forage legumes white clover (Trifolium repens L.) and alfalfa (Medicago sativa L.) were discriminated based on the presence or absence of oxylipins, a class of endogenous antimicrobial compounds. Unwashed seeds confer toxicity towards symbiotic, nitrogen-fixing rhizobia which are routinely coated on legume seeds before planting, resulting in reduced rhizobial count. This is the first report of automatic introduction of intact seeds in the DART ion source and detecting oxylipins using DART-MS. Apart from providing scope to investigate legume-rhizobia symbiosis further in the context of oxylipins, the results presented here will enable future studies aimed at classification of seeds based on chemicals bound to the seed coat, thereby offering an efficient screening device for industry.

  3. 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. PMID:27527103

  4. Library screening by means of mass spectrometry (MS) binding assays-exemplarily demonstrated for a pseudostatic library addressing γ-aminobutyric acid (GABA) transporter 1 (GAT1).

    PubMed

    Sindelar, Miriam; Wanner, Klaus T

    2012-09-01

    In the present study, the application of mass spectrometry (MS) binding assays as a tool for library screening is reported. For library generation, dynamic combinatorial chemistry (DCC) was used. These libraries can be screened by means of MS binding assays when appropriate measures are taken to render the libraries pseudostatic. That way, the efficiency of MS binding assays to determine ligand binding in compound screening with the ease of library generation by DCC is combined. The feasibility of this approach is shown for γ-aminobutyric acid (GABA) transporter 1 (GAT1) as a target, representing the most important subtype of the GABA transporters. For the screening, hydrazone libraries were employed that were generated in the presence of the target by reacting various sets of aldehydes with a hydrazine derivative that is delineated from piperidine-3-carboxylic acid (nipecotic acid), a common fragment of known GAT1 inhibitors. To ensure that the library generated is pseudostatic, a large excess of the nipecotic acid derivative is employed. As the library is generated in a buffer system suitable for binding and the target is already present, the mixtures can be directly analyzed by MS binding assays-the process of library generation and screening thus becoming simple to perform. The binding affinities of the hits identified by deconvolution were confirmed in conventional competitive MS binding assays performed with single compounds obtained by separate synthesis. In this way, two nipecotic acid derivatives exhibiting a biaryl moiety, 1-{2-[2'-(1,1'-biphenyl-2-ylmethylidene)hydrazine]ethyl}piperidine-3-carboxylic acid and 1-(2-{2'-[1-(2-thiophenylphenyl)methylidene]hydrazine}ethyl)piperidine-3-carboxylic acid, were found to be potent GAT1 ligands exhibiting pK(i) values of 6.186 ± 0.028 and 6.229 ± 0.039, respectively. This method enables screening of libraries, whether generated by conventional chemistry or DCC, and is applicable to all kinds of targets including

  5. Library screening by means of mass spectrometry (MS) binding assays-exemplarily demonstrated for a pseudostatic library addressing γ-aminobutyric acid (GABA) transporter 1 (GAT1).

    PubMed

    Sindelar, Miriam; Wanner, Klaus T

    2012-09-01

    In the present study, the application of mass spectrometry (MS) binding assays as a tool for library screening is reported. For library generation, dynamic combinatorial chemistry (DCC) was used. These libraries can be screened by means of MS binding assays when appropriate measures are taken to render the libraries pseudostatic. That way, the efficiency of MS binding assays to determine ligand binding in compound screening with the ease of library generation by DCC is combined. The feasibility of this approach is shown for γ-aminobutyric acid (GABA) transporter 1 (GAT1) as a target, representing the most important subtype of the GABA transporters. For the screening, hydrazone libraries were employed that were generated in the presence of the target by reacting various sets of aldehydes with a hydrazine derivative that is delineated from piperidine-3-carboxylic acid (nipecotic acid), a common fragment of known GAT1 inhibitors. To ensure that the library generated is pseudostatic, a large excess of the nipecotic acid derivative is employed. As the library is generated in a buffer system suitable for binding and the target is already present, the mixtures can be directly analyzed by MS binding assays-the process of library generation and screening thus becoming simple to perform. The binding affinities of the hits identified by deconvolution were confirmed in conventional competitive MS binding assays performed with single compounds obtained by separate synthesis. In this way, two nipecotic acid derivatives exhibiting a biaryl moiety, 1-{2-[2'-(1,1'-biphenyl-2-ylmethylidene)hydrazine]ethyl}piperidine-3-carboxylic acid and 1-(2-{2'-[1-(2-thiophenylphenyl)methylidene]hydrazine}ethyl)piperidine-3-carboxylic acid, were found to be potent GAT1 ligands exhibiting pK(i) values of 6.186 ± 0.028 and 6.229 ± 0.039, respectively. This method enables screening of libraries, whether generated by conventional chemistry or DCC, and is applicable to all kinds of targets including

  6. Gram-Stain Plus MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry) for a Rapid Diagnosis of Urinary Tract Infection

    PubMed Central

    Burillo, Almudena; Rodríguez-Sánchez, Belén; Ramiro, Ana; Cercenado, Emilia; Rodríguez-Créixems, Marta; Bouza, Emilio

    2014-01-01

    Microbiological confirmation of a urinary tract infection (UTI) takes 24–48 h. In the meantime, patients are usually given empirical antibiotics, sometimes inappropriately. We assessed the feasibility of sequentially performing a Gram stain and MALDI-TOF MS mass spectrometry (MS) on urine samples to anticipate clinically useful information. In May-June 2012, we randomly selected 1000 urine samples from patients with suspected UTI. All were Gram stained and those yielding bacteria of a single morphotype were processed for MALDI-TOF MS. Our sequential algorithm was correlated with the standard semiquantitative urine culture result as follows: Match, the information provided was anticipative of culture result; Minor error, the information provided was partially anticipative of culture result; Major error, the information provided was incorrect, potentially leading to inappropriate changes in antimicrobial therapy. A positive culture was obtained in 242/1000 samples. The Gram stain revealed a single morphotype in 207 samples, which were subjected to MALDI-TOF MS. The diagnostic performance of the Gram stain was: sensitivity (Se) 81.3%, specificity (Sp) 93.2%, positive predictive value (PPV) 81.3%, negative predictive value (NPV) 93.2%, positive likelihood ratio (+LR) 11.91, negative likelihood ratio (−LR) 0.20 and accuracy 90.0% while that of MALDI-TOF MS was: Se 79.2%, Sp 73.5, +LR 2.99, −LR 0.28 and accuracy 78.3%. The use of both techniques provided information anticipative of the culture result in 82.7% of cases, information with minor errors in 13.4% and information with major errors in 3.9%. Results were available within 1 h. Our serial algorithm provided information that was consistent or showed minor errors for 96.1% of urine samples from patients with suspected UTI. The clinical impacts of this rapid UTI diagnosis strategy need to be assessed through indicators of adequacy of treatment such as a reduced time to appropriate empirical treatment or earlier

  7. A novel quantification strategy of transferrin and albumin in human serum by species-unspecific isotope dilution laser ablation inductively coupled plasma mass spectrometry (ICP-MS).

    PubMed

    Feng, Liuxing; Zhang, Dan; Wang, Jun; Shen, Dairui; Li, Hongmei

    2015-07-16

    Species-specific (SS) isotope dilution analysis with gel electrophoresis (GE)-laser ablation (LA)-ICP-MS is a promising technique for the quantification of particular metal-binding proteins in biological samples. However, unavailable isotopically enriched spike and metal losses in GE separation are main limitations for SS-isotope dilution PAGE-LA-ICP-MS. In this study, we report for the first time the absolute quantification of transferrin (Tf) and albumin (Alb) in human serum by non-denaturing (native) GE combined with species-unspecific isotope dilution mass spectrometry (IDMS). In order to achieve a homogeneous distribution of both protein and isotope-enriched spike (simulated isotope equilibration), immersing the protein strips with (34)S spike solution after gel electrophoresis was demonstrated to be an effective way of spike addition. Furthermore, effects of immersion time and (34)S spike concentration were investigated to obtain optimal conditions of the post-electrophoresis isotope dilution method. The relative mass of spike and ablated sample (m(sp)/m(sam)) in IDMS equation was calculated by standard Tf and Alb proteins, which could be applied to the quantification of Tf and Alb in ERM-DA470k/IFCC for method confirmation. The results were in agreement with the certified value with good precision and small uncertainty (1.5-3%). In this method, species-specific spike protein is not necessary and the integrity of the heteroatom-protein could be maintained in sample preparation process. Moreover, the application of species-unspecific isotope dilution GE-LA-ICP-MS has the potential to offer reliable, direct and simultaneous quantification of proteins after conventional 1D and 2D gel electrophoretic separations.

  8. 4-Chloro-α-cyanocinnamic acid is an efficient soft matrix for cyanocobalamin detection in foodstuffs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS).

    PubMed

    Calvano, Cosima Damiana; Ventura, Giovanni; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-09-01

    4-Chloro-α-cyanocinnamic acid (ClCCA) is a very useful matrix able to give the protonated adduct [M+H](+) of intact cyanocobalamin (CNCbl) as the base peak (m/z 1355.58) in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The only fragment observed is [M-CN + H](+•) formed through the facile (•) CN neutral loss reflecting the fairly low Co-C bond energy. All other investigated proton transfer matrices, including α-cyano-4-hydroxycinnamic acid, para-nitroaniline and 2,5-dihydroxybenzoic acid, give rise to a complete decyanation of CNCbl with concomitant formation of [M-CN + H](+•) , [M-CN + Na](+•) and [M-CN + K](+•) adducts at m/z 1329.57, 1351.55 and 1367.51, respectively. Depending on the matrix used, a variable degree of fragmentation involving the α-side axial ligand was observed. A plausible explanation of the specific behaviour of 4-chloro-α-cyanocinnamic acid as a soft matrix is discussed. Tandem mass spectra of both [M + H](+) and [M-CN + H](+•) ions were obtained and product ions successfully assigned. The possibility of detecting the protonated adduct of intact CNCbl was exploited in foodstuff samples such as cow milk and hen egg yolk by MALDI tandem MS upon sample extraction. We believe that our data provide strong basis for the application of MALDI tandem MS in the qualitative analysis of natural CNCbl, including fish, liver and meat samples. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27468135

  9. Exploiting dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) for sequential determination of trace elements in blood using a dilute-and-shoot procedure.

    PubMed

    Batista, Bruno Lemos; Rodrigues, Jairo Lisboa; Nunes, Juliana Andrade; Souza, Vanessa Cristina de Oliveira; Barbosa, Fernando

    2009-04-20

    Inductively coupled plasma mass spectrometry with quadrupole (q-ICP-MS) and dynamic reaction cell (DRC-ICP-MS) were evaluated for sequential determination of As, Cd, Co, Cr, Cu, Mn, Pb, Se, Tl, V and Zn in blood. The method requires as little as 100 microL of blood. Prior to analysis, samples (100 microL) were diluted 1:50 in a solution containing 0.01% (v/v) Triton X-100 and 0.5% (v/v) nitric acid. The use of the DRC was only mandatory for Cr, Cu, V and Zn. For the other elements the equipment may be operated in a standard mode (q-ICP-MS). Ammonia was used as reaction gas. Selection of best flow rate of ammonium gas and optimization of the quadrupole dynamic band-pass tuning parameter (RPq) were carried out, using a ovine base blood for Cr and V and a synthetic matrix solution (SMS) for Zn and Cu diluted 1:50 and spiked to contain 1 microg L(-1) of each element. Method detection limits (3 s) for (75)As, (114)Cd, (59)Co, (51)Cr, (63)Cu (55)Mn, (208)Pb, (82)Se, (205)Tl, (51)V, and (64)Zn were 14.0, 3.0, 11.0, 7.0, 280, 9.0, 3.0, 264, 0.7, 6.0 and 800 ng L(-1), respectively. Method validation was accomplished by the analysis of blood Reference Materials produced by the L'Institut National de Santé Publique du Quebec (Canada).

  10. Analysis of methicillin-resistant Staphylococcus aureus major clonal lineages by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

    PubMed

    Zhang, Tingting; Ding, Jinya; Rao, Xiancai; Yu, Jingbo; Chu, Meiling; Ren, Wei; Wang, Lu; Xue, Wencheng

    2015-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen associated with nosocomial infections in many countries. Multilocus sequence typing (MLST) is one of the genetic typing methods used to type MRSA with a high discriminatory power, however, it is labor-intensive, timely, and costly. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled with ClinProTools is a potential tool to discover biomarker peaks and to generate a classification model based on highly sophisticated mathematical algorithms to discriminate clonal lineages. We investigated the performance of MALDI-TOF MS for discriminating 154 MRSA-ST239, 72 MRSA-ST5, 30 MRSA-ST59, 14 MRSA-ST45, and 20 MRSA-OST (other clonal lineages). Our results indicate that the model construction and validation have good potency to discriminate ST45 from other lineages with a sensitivity and a specificity of both 100%, and a sensitivity of 95.80% and a specificity of 94.62% to identify ST239. For Biotyper classification, the sensitivity and specificity were more than of 90% for ST239, ST59 and ST45, whereas only 81.94% sensitivity for ST5. By single-peak analysis, the peaks m/z 4808 and 9614 can correctly discriminate ST45 a sensitivity and a specificity of both 100%; the peak m/z 6554 can also discriminate ST239 with a sensitivity of 91.9% and a specificity of 85.4%. In conclusion, MALDI-TOF MS coupled with ClinProTools has a high detection performance for MRSA typing with obvious advantages of being rapid, highly accurate, and being a low cost in comparison with MLST.

  11. Molecular characterisation of soil organic matter by laser-desorption ionization Fourier-transform ion cyclotron resonance mass spectrometry (LDI-FT-ICR-MS)

    NASA Astrophysics Data System (ADS)

    Abiven, S.; Fuchser, J.; Schmidt, M. W. I.; Dittmar, T.

    2012-04-01

    Soil organic matter (SOM) characterisation has been an analytical challenge for decades. On one hand, methods like humic substances extraction describe large pools of molecules, but these extractions target operationnally- rather than chemically-defined pools. On the other hand, specific compound analysis provides a more precise overview on the molecules present in the soil, but the sum of these molecules represents only a minor portion of the soil organic matter. Despite these shortcomings, soil organic matter characterisation is used in many concepts of soil science. For example, the soil aggregation hierarchical model describes the physical organisation of soils into fractions bound together by organic matter of different quality for each size fraction. Due to the method inadequation, most of these concepts still need to be validated. We took advantage of a unique analytical set-up coupling laser-desorption ionization (LDI) to ultrahigh-resolution mass spectrometry via the Fourier-transform ion cyclotron resonance technique (FT-ICR-MS) to further characterise soil organic matter and to validate the soil aggregation hierarchical model. Soil aggregates (3-5 mm) were collected from two soils, a cambisol (32 % clay, 4.2 %C), and a loess-derived soil (15% clay, 1.6 %C). Aggregates were fractionated by fast wetting into <63, 63-125, 125-250 and > 250 μm fractions. These fractions were air-dried and ground to powder prior to analysis. LDI-FT-ICR-MS analyses were performed on otherwise untreated samples. Thousands of molecular formulae were identified in each samples, many of them could be associated with polyphenolic structures. The combination of LDI with ultrahigh-resolution FT-ICR-MS offers fundmentally new insights into soil organic matter, one of the largest organic matter pools on Earth.

  12. Bottom-up approach for the reaction of xenobiotics and their metabolites with model substances for natural organic matter by electrochemistry-mass spectrometry (EC-MS).

    PubMed

    Chen, Lei; Hofmann, Diana; Klumpp, Erwin; Xiang, Xinyi; Chen, Yingxu; Küppers, Stephan

    2012-11-01

    Risk assessment of xenobiotics requires a comprehensive understanding of their transformation in the environment. As most of the transformation processes usually involve a redox reaction or a hydrolysis as the first steps of the transformation, we applied an approach that uses an electrochemical cell to investigate model "redox" reactions in aqueous solutions for environmental processes. We investigated the degradation of a variety of xenobiotics from polar to nonpolar and analyzed their degradation products by on-line coupling of electrochemistry with mass spectrometry (EC-MS). Furthermore, we evaluated possible binding reactions with regard to the generation of non-extractable residues with some model substances (catechol, phthalic acid, γ-L-Glutamyl-L-cysteinyl-glycine (GSH) and L-histidine) deduced from a natural organic matter (NOM) structure model and identified possible binding-sites. Whereas typically investigations in soil/water-systems have been applied, we used to our knowledge for the first time a bottom-up approach, starting from the chemicals of interest and different model substances for natural organic matter to evaluate chemical binding mechanisms (or processes) in the EC-MS under redox conditions. Under oxidative conditions, bindings of the xenobiotics with catechol, GSH and histidine were found, but no reactions with the model compound phthalic acid were observed. In general, no chemical binding has yet been found under reductive conditions. In some cases (i.e. benzo[a]anthracene) the oxidation product only underwent a binding reaction, whereas the xenobiotic itself did not undergo any reactions. EC-MS is a promising fast and simple screening method to investigate the environmental behavior of xenobiotics and to evaluate the potential risks of newly synthesized substances.

  13. 4-Chloro-α-cyanocinnamic acid is an efficient soft matrix for cyanocobalamin detection in foodstuffs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS).

    PubMed

    Calvano, Cosima Damiana; Ventura, Giovanni; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-09-01

    4-Chloro-α-cyanocinnamic acid (ClCCA) is a very useful matrix able to give the protonated adduct [M+H](+) of intact cyanocobalamin (CNCbl) as the base peak (m/z 1355.58) in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The only fragment observed is [M-CN + H](+•) formed through the facile (•) CN neutral loss reflecting the fairly low Co-C bond energy. All other investigated proton transfer matrices, including α-cyano-4-hydroxycinnamic acid, para-nitroaniline and 2,5-dihydroxybenzoic acid, give rise to a complete decyanation of CNCbl with concomitant formation of [M-CN + H](+•) , [M-CN + Na](+•) and [M-CN + K](+•) adducts at m/z 1329.57, 1351.55 and 1367.51, respectively. Depending on the matrix used, a variable degree of fragmentation involving the α-side axial ligand was observed. A plausible explanation of the specific behaviour of 4-chloro-α-cyanocinnamic acid as a soft matrix is discussed. Tandem mass spectra of both [M + H](+) and [M-CN + H](+•) ions were obtained and product ions successfully assigned. The possibility of detecting the protonated adduct of intact CNCbl was exploited in foodstuff samples such as cow milk and hen egg yolk by MALDI tandem MS upon sample extraction. We believe that our data provide strong basis for the application of MALDI tandem MS in the qualitative analysis of natural CNCbl, including fish, liver and meat samples. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Distinct energy metabolism of auditory and vestibular sensory epithelia revealed by quantitative mass spectrometry using MS2 intensity.

    PubMed

    Spinelli, Kateri J; Klimek, John E; Wilmarth, Phillip A; Shin, Jung-Bum; Choi, Dongseok; David, Larry L; Gillespie, Peter G

    2012-01-31

    Measuring the abundance of many proteins over a broad dynamic range requires accurate quantitation. We show empirically that, in MS experiments, relative quantitation using summed dissociation-product ion-current intensities is accurate, albeit variable from protein to protein, and outperforms spectral counting. By applying intensities to quantify proteins in two complex but related tissues, chick auditory and vestibular sensory epithelia, we find that glycolytic enzymes are enriched threefold in auditory epithelia, whereas enzymes responsible for oxidative phosphorylation are increased at least fourfold in vestibular epithelia. This striking difference in relative use of the two ATP-production pathways likely reflects the isolation of the auditory epithelium from its blood supply, necessary to prevent heartbeat-induced mechanical disruptions. The global view of protein expression afforded by label-free quantitation with a wide dynamic range reveals molecular specialization at a tissue or cellular level.

  15. The determination of sulfonamides in honey by high performance liquid chromatography--mass spectrometry method (LC/MS).

    PubMed

    Krivohlavek, Adela; Smit, Zdenko; Bastinac, Martina; Zuntar, Irena; Plavic-Plavsic, Franjo

    2005-08-01

    The sulfonamides (SAs) are stable chemotherapeutics used against the bacterial disease affecting bees, known as American foulbrood (Bacillus larvae), so their residues could appear in the honey of treated bees. Their presence at a concentration above the limit value could be a potential danger to human health. Therefore, a simple, rapid, and reliable method for determination of 11 available SAs in honey was optimized. The samples were homogenized and cleaned with extraction on solid phase by means of Chromabond C18 end-capped cartridge followed by LC/MS analyses. A detection limit of 25 microg/kg was achieved for all analytes. The repeatability of the method was proven and the optimal parameters for temperature and pH of the mobile phase and acetic buffer, respectively, were determined. In this study, 20 samples of domestic honey were included. Six of the analyzed samples were positive, but all results were below the Croatian permissible limit value (100 microg/kg).

  16. Determination of 241Am in Urine Using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS)

    PubMed Central

    Xiao, Ge; Saunders, David; Jones, Robert L.; Caldwell, Kathleen L.

    2016-01-01

    Quantification of 241Am in urine at low levels is important for assessment of individuals’ or populations’ accidental, environmental, or terrorism-related internal contamination, but no convenient, precise method has been established to rapidly determine these low levels. Here we report a new analytical method to measure 241Am as developed and validated at the Centers for Disease Control and Prevention (CDC) by means of the selective retention of Am from urine directly on DGA resin, followed by SF-ICP-MS detection. The method provides rapid results with a Limit of Detection (LOD) of 0.22 pg/L (0.028 Bq/L), which is lower than 1/3 of the C/P CDG for 241Am at 5 days post-exposure. The results obtained by this method closely agree with CDC values as measured by Liquid Scintillation Counting, and with National Institute of Standards Technology (NIST) Certified Reference Materials (CRM) target values. PMID:27375308

  17. Determination of T-2 toxin, HT-2 toxin, and three other type A trichothecenes in layer feed by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS)--comparison of two sample preparation methods.

    PubMed

    Bernhardt, Katrin; Valenta, Hana; Kersten, Susanne; Humpf, Hans-Ulrich; Dänicke, Sven

    2016-05-01

    A sensitive method for the simultaneous determination of T-2 toxin, HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol in layer feed using high-performance liquid chromatography coupled to triple quadrupole mass spectrometry in the positive ionization mode (LC-ESI-MS/MS) is described. Two fast and easy clean-up methods-with BondElut Mycotoxin and MycoSep 227 columns, respectively-were tested. The separation of the toxins was conducted on a Pursuit XRs Ultra 2.8 HPLC column using 0.13 mM ammonium acetate as eluent A and methanol as eluent B. Detection of the mycotoxins was carried out in the multiple reaction monitoring (MRM) mode using ammonium adducts as precursor ions. Quantification of all analytes was performed with d3-T-2 toxin as an internal standard. The clean-up method with MycoSep 227 columns gave slightly better results for layer feed compared to the method using BondElut Mycotoxin columns (MycoSep 227: recovery between 50 and 63%, BondElut Mycotoxin: recovery between 32 and 67%) and was therefore chosen as the final method. The limits of detection ranged between 0.9 and 7.5 ng/g depending on the mycotoxin. The method was developed for the analysis of layer feed used at carry-over experiments with T-2 toxin in laying hens. For carry-over experiments, it is necessary that the method includes not only T-2 toxin but also the potential metabolites in animal tissues HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol which could naturally occur in cereals used as feed stuff as well. PMID:26940912

  18. Characterisation of steroids in wooden crates of veal calves by accelerated solvent extraction (ASE) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-QqQ-MS-MS).

    PubMed

    Verheyden, K; Noppe, H; Vanden Bussche, J; Wille, K; Bekaert, K; De Boever, L; Van Acker, J; Janssen, C R; De Brabander, H F; Vanhaecke, L

    2010-05-01

    Illegal steroid administration to enhance growth performance in veal calves has long been, and still is, a serious issue facing regulatory agencies. Over the last years, stating undisputable markers of illegal treatment has become complex because of the endogenous origin of several anabolic steroids. Knowledge on the origin of an analyte is therefore of paramount importance. The present study shows the presence of steroid analytes in wooden crates used for housing veal calves. For this purpose, an analytical procedure using accelerated solvent extraction (ASE(R)), solid-phase extraction (SPE) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-MS-MS) is developed for the characterisation of androstadienedione (ADD), boldenone (bBol), androstenedione (AED), beta-testosterone (bT), alpha-testosterone (aT), progesterone (P) and 17alpha-hydroxy-progesterone (OH-P) in wood samples. In samples of wooden crates used for housing veal calves, ADD, AED, aT and P could be identified. Using the standard addition approach concentrations of these analytes were determined ranging from 20 +/- 4 ppb to 32 +/- 4 ppb for ADD, from 19 +/- 5 ppb to 44 +/- 17 ppb for AED, from 11 +/- 6 ppb to 30 +/- 2 ppb for aT and from 14 +/- 1 ppb to 42 +/- 27 ppb for P, depending on the sample type. As exposure of veal calves to steroid hormones in their housing facilities might complicate decision-making on illegal hormone administration, inequitable slaughter of animals remains possible. Therefore, complete prohibition of wooden calf accommodation should be considered. PMID:20186540

  19. Analysis of carbohydrates in Fusarium verticillioides using size-exclusion HPLC – DRI and direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS) and size-exclusion HPLC – DRI are used, respectively, to qualitatively and quantitatively determine the carbohydrates extracted from the corn rot fungus Fusarium verticillioides. In situ permethylation in the DART...

  20. Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Nascimento, Eduardo S P; Cardoso, Daniel R; Franco, Douglas W

    2008-07-23

    An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) microg L(-1), whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected, ethyl acetate is the major ester in whiskey and rum, followed by ethyl lactate for samples of rum. Nevertheless, whiskey samples exhibit ethyl lactate at contents lower or at the same order of magnitude of the fatty esters.

  1. Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Nascimento, Eduardo S P; Cardoso, Daniel R; Franco, Douglas W

    2008-07-23

    An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) microg L(-1), whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected, ethyl acetate is the major ester in whiskey and rum, followed by ethyl lactate for samples of rum. Nevertheless, whiskey samples exhibit ethyl lactate at contents lower or at the same order of magnitude of the fatty esters. PMID:18570431

  2. Rapid and reliable species identification of wild mushrooms by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS).

    PubMed

    Sugawara, Ryota; Yamada, Sayumi; Tu, Zhihao; Sugawara, Akiko; Suzuki, Kousuke; Hoshiba, Toshihiro; Eisaka, Sadao; Yamaguchi, Akihiro

    2016-08-31

    Mushrooms are a favourite natural food in many countries. However, some wild species cause food poisoning, sometimes lethal, due to misidentification caused by confusing fruiting bodies similar to those of edible species. The morphological inspection of mycelia, spores and fruiting bodies have been traditionally used for the identification of mushrooms. More recently, DNA sequencing analysis has been successfully applied to mushrooms and to many other species. This study focuses on a simpler and more rapid methodology for the identification of wild mushrooms via protein profiling based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). A preliminary study using 6 commercially available cultivated mushrooms suggested that a more reproducible spectrum was obtained from a portion of the cap than from the stem of a fruiting body by the extraction of proteins with a formic acid-acetonitrile mixture (1 + 1). We used 157 wild mushroom-fruiting bodies collected in the centre of Hokkaido from June to November 2014. Sequencing analysis of a portion of the ribosomal RNA gene provided 134 identifications of mushrooms by genus or species, however 23 samples containing 10 unknown species that had lower concordance rate of the nucleotide sequences in a BLAST search (less than 97%) and 13 samples that had unidentifiable poor or mixed sequencing signals remained unknown. MALDI-TOF MS analysis yielded a reproducible spectrum (frequency of matching score ≥ 2.0 was ≥6 spectra from 12 spectra measurements) for 114 of 157 samples. Profiling scores that matched each other within the database gave correct species identification (with scores of ≥2.0) for 110 samples (96%). An in-house prepared database was constructed from 106 independent species, except for overlapping identifications. We used 48 wild mushrooms that were collected in autumn 2015 to validate the in-house database. As a result, 21 mushrooms were identified at the species level with

  3. Rapid and reliable species identification of wild mushrooms by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS).

    PubMed

    Sugawara, Ryota; Yamada, Sayumi; Tu, Zhihao; Sugawara, Akiko; Suzuki, Kousuke; Hoshiba, Toshihiro; Eisaka, Sadao; Yamaguchi, Akihiro

    2016-08-31

    Mushrooms are a favourite natural food in many countries. However, some wild species cause food poisoning, sometimes lethal, due to misidentification caused by confusing fruiting bodies similar to those of edible species. The morphological inspection of mycelia, spores and fruiting bodies have been traditionally used for the identification of mushrooms. More recently, DNA sequencing analysis has been successfully applied to mushrooms and to many other species. This study focuses on a simpler and more rapid methodology for the identification of wild mushrooms via protein profiling based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). A preliminary study using 6 commercially available cultivated mushrooms suggested that a more reproducible spectrum was obtained from a portion of the cap than from the stem of a fruiting body by the extraction of proteins with a formic acid-acetonitrile mixture (1 + 1). We used 157 wild mushroom-fruiting bodies collected in the centre of Hokkaido from June to November 2014. Sequencing analysis of a portion of the ribosomal RNA gene provided 134 identifications of mushrooms by genus or species, however 23 samples containing 10 unknown species that had lower concordance rate of the nucleotide sequences in a BLAST search (less than 97%) and 13 samples that had unidentifiable poor or mixed sequencing signals remained unknown. MALDI-TOF MS analysis yielded a reproducible spectrum (frequency of matching score ≥ 2.0 was ≥6 spectra from 12 spectra measurements) for 114 of 157 samples. Profiling scores that matched each other within the database gave correct species identification (with scores of ≥2.0) for 110 samples (96%). An in-house prepared database was constructed from 106 independent species, except for overlapping identifications. We used 48 wild mushrooms that were collected in autumn 2015 to validate the in-house database. As a result, 21 mushrooms were identified at the species level with

  4. Studies on thermal decomposition mechanism of CL-20 by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS).

    PubMed

    Naik, N H; Gore, G M; Gandhe, B R; Sikder, A K

    2008-11-30

    The thermal decomposition study of CL-20 (hexanitrohexaazaisowurtzitane) using pyrolysis GC/MS was carried out mainly by electron impact (EI) mode. Chemical ionization (CI) mode was used for further confirmation of identified species. Mass spectrum of CL-20 decomposition products predominantly revealed fragments with m/z 81 and 96 corresponding to C(4)H(5)N(2)(+) and C(4)H(4)N(2)O(+) ions, respectively. The total ion chromatogram (TIC) of CL-20 pyrolysis shows peak within first 2 min due to the presence of low molecular weight gases. Peaks corresponding to several other products were also observed including the atmospheric gases. Cyanogen formation (C(2)N(2), m/z 52) observed to be enriched at the scan number 300-500. The low molecular mass range decomposition products formed by cleavage of C-N ring structure were found in majority. Additional structural information was sought by employing chemical ionization mode. The data generated during this study was instrumented in determining decomposition pathways of CL-20.

  5. Studies on thermal decomposition mechanism of CL-20 by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS).

    PubMed

    Naik, N H; Gore, G M; Gandhe, B R; Sikder, A K

    2008-11-30

    The thermal decomposition study of CL-20 (hexanitrohexaazaisowurtzitane) using pyrolysis GC/MS was carried out mainly by electron impact (EI) mode. Chemical ionization (CI) mode was used for further confirmation of identified species. Mass spectrum of CL-20 decomposition products predominantly revealed fragments with m/z 81 and 96 corresponding to C(4)H(5)N(2)(+) and C(4)H(4)N(2)O(+) ions, respectively. The total ion chromatogram (TIC) of CL-20 pyrolysis shows peak within first 2 min due to the presence of low molecular weight gases. Peaks corresponding to several other products were also observed including the atmospheric gases. Cyanogen formation (C(2)N(2), m/z 52) observed to be enriched at the scan number 300-500. The low molecular mass range decomposition products formed by cleavage of C-N ring structure were found in majority. Additional structural information was sought by employing chemical ionization mode. The data generated during this study was instrumented in determining decomposition pathways of CL-20. PMID:18468788

  6. Trace elemental analysis of automotive paints by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).

    PubMed

    Hobbs, Andria L; Almirall, José R

    2003-08-01

    Paints and coatings are frequently encountered as types of materials that are submitted to forensic science laboratories as a result of trace evidence transfers. The aim of this study was to develop a method to complement the commonly used techniques in a forensic laboratory in order to better characterize these samples for forensic purposes. A laser ablation method has been used to simultaneously sample several layers directly prior to introduction into an inductively coupled plasma-mass spectrometer for the detection and quantification of the trace metals present in the layer(s). Time-resolved analysis plots displaying the elemental response and quantification of selected metals are compared to associate/discriminate paint samples. Matrix-matched standards were successfully incorporated into the analysis scheme for quantification of lead in the solid paint samples. Preparation of new matrix-matched standards for quantification of additional elements developed for this study are also presented. A sample set of eighteen (18) survey automotive paint samples have been analyzed with the developed method in order to determine the utility of LA-ICP-MS for trace element analysis of paints.

  7. Analysis of the chemical composition of the essential oil of Polygonum minus Huds. using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC-TOF MS).

    PubMed

    Baharum, Syarul Nataqain; Bunawan, Hamidun; Ghani, Ma'aruf Abd; Mustapha, Wan Aida Wan; Noor, Normah Mohd

    2010-10-12

    The essential oil in leaves of Polygonum minus Huds., a local aromatic plant, were identified by a pipeline of gas chromatography (GC) techniques coupled with mass-spectrometry (MS), flame ionization detector (FID) and two dimensional gas chromatography time of flight mass spectrometry (GC x GC-TOF MS). A total of 48 compounds with a good match and high probability values were identified using this technique. Meanwhile, 42 compounds were successfully identified in this study using GC-MS, a significantly larger number than in previous studies. GC-FID was used in determining the retention indices of chemical components in P. minus essential oil. The result also showed the efficiency and reliability were greatly improved when chemometric methods and retention indices were used in identification and quantification of chemical components in plant essential oil.

  8. Ultra high performance supercritical fluid chromatography coupled with tandem mass spectrometry for screening of doping agents. I: Investigation of mobile phase and MS conditions.

    PubMed

    Nováková, Lucie; Grand-Guillaume Perrenoud, Alexandre; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

    2015-01-01

    The conditions for the analysis of selected doping substances by UHPSFC-MS/MS were optimized to ensure suitable peak shapes and maximized MS responses. A representative mixture of 31 acidic and basic doping agents was analyzed, in both ESI+ and ESI- modes. The best compromise for all compounds in terms of MS sensitivity and chromatographic performance was obtained when adding 2% water and 10mM ammonium formate in the CO2/MeOH mobile phase. Beside mobile phase, the nature of the make-up solvent added for interfacing UHPSFC with MS was also evaluated. Ethanol was found to be the best candidate as it was able to compensate for the negative effect of 2% water addition in ESI- mode and provided a suitable MS response for all doping agents. Sensitivity of the optimized UHPSFC-MS/MS method was finally assessed and compared to the results obtained in conventional UHPLC-MS/MS. Sensitivity was improved by 5-100-fold in UHPSFC-MS/MS vs. UHPLC-MS/MS for 56% of compounds, while only one compound (bumetanide) offered a significantly higher MS response (4-fold) under UHPLC-MS/MS conditions. In the second paper of this series, the optimal conditions for UHPSFC-MS/MS analysis will be employed to screen >100 doping agents in urine matrix and results will be compared to those obtained by conventional UHPLC-MS/MS.

  9. Expediting the method development and quality control of reversed-phase liquid chromatography electrospray ionization mass spectrometry for pharmaceutical analysis by using an LC/MS performance test mix.

    PubMed

    Tang, L; Fitch, W L; Alexander, M S; Dolan, J W

    2000-11-01

    Mass spectrometry combined with liquid chromatography (LC/MS) has become an important analytical methodology in both pharmaceutical and biomolecule analyses. LC/MS, especially with reversed-phase HPLC (RP-LC), is extensively used in the separation and structural identification of pharmaceutical samples. However, many parameters have to be considered when a new LC/MS method is developed for either separation and structural analysis of unknown mixtures or quantitative analysis of a set of known compounds in an assay. The optimization of a new LC/MS method can be a time-consuming process. A novel kit-LC/MS performance test mix-composed of aspartame, cortisone, reserpine, and dioctyl phthalate has been developed to accelerate the process of establishing a new RP-LC/MS method. The LC/MS mix makes the evaluation and validation of an LC/MS method more efficient and easier. It also simplifies the quality control procedure for an LC/MS method in use.

  10. Ion-pair chromatography coupled to inductively coupled plasma-mass spectrometry (IPC-ICP-MS) as a method for thiomolybdate speciation in natural waters.

    PubMed

    Lohmayer, Regina; Reithmaier, Gloria Maria Susanne; Bura-Nakić, Elvira; Planer-Friedrich, Britta

    2015-03-17

    Molybdenum precipitates preferentially under reducing conditions; therefore, its occurrence in sediment records is used as an indicator of paleoredox conditions. Although thiomolybdates (MoO4-xSx(2-) with x = 1-4) supposedly are necessary intermediates in the process of molybdenum precipitation under anoxic conditions, there is no information about their abundance in natural environments, because of a lack of element-specific methods with sufficiently low detection limits. Here, we optimized ion-pair chromatographic separation for coupling to an inductively coupled plasma-mass spectrometry detector (IPC-ICP-MS). 2-Propanol (10%-25% gradient) replaced the previously used acetonitrile (25%-75%) as the solvent, to reduce the carbon load into the plasma. In synthetic solutions, formation of thiomolybdates was found to occur spontaneously in the presence of excess sulfide and the degree of thiolation was highest at pH 7. Excess hydroxyl led to a transformation of thiomolybdates to molybdate. Under acidic to neutral conditions, precipitation of molybdenum and hydrolysis of tetrathiomolybdate were observed. Flash-freezing was found to be suitable to stabilize tetrathiomolybdate, with <4% transformation over more than two months. High ionic strengths matrices (>2 mM) negatively affected the detection of molybdate, which eluted mainly in the dead volume, but had no negative effect on higher thiolated molybdates. Detection limits were ∼10 nM. With the newly developed IPC-ICP-MS method, thiomolybdates were found to form spontaneously in euxinic marine waters after adding a molybdate spike and occur naturally in sulfidic geothermal waters.

  11. Liquid chromatography/negative electrospray ionization ion trap MS(2) mass spectrometry application for the determination of microcystins occurrence in Southern Portugal water reservoirs.

    PubMed

    Rodrigues, M A; Reis, M P; Mateus, M C

    2013-11-01

    Microcystins (MCs) are toxins produced by cyanobacteria which are common organisms in the phytoplankton of eutrophic lakes, rivers and freshwater reservoirs. In the present work, a novel method of liquid chromatography-electrospray ion trap tandem mass spectrometry (LC/ESI/Ion trap-MS/MS), operated in the negative ionization mode, was developed for the analysis of these cyanotoxins. The method was applied to determine the amounts of total microcystins-LR, -YR and -RR in two water reservoirs in Southern Portugal, namely Alqueva and Beliche. A total of 30 water samples were analysed along 2011. Solid phase extraction (SPE) was used for sample cleaning-up and analyte enrichment. The extracted toxins were separated on a C18 column with a gradient of acetonitrile/water with 0.1% formic acid. Detection of microcystins was carried out using multiple reaction monitoring (MRM) in the negative polarity mode, as this method gave a higher selectivity. The MC-RR, YR and LR quantification limits were 17.9, 31.7 and 15.8 ng/L, respectively; quite below the limits recommended by WHO guidelines for drinking water (1 μg/L). Total MC highest concentrations were found in the warm months of June, July and September in Alqueva sampling sites, with concentrations of MC LR and RR ranging 17-344 and 25-212 ng/L, respectively, showing comparable results for MC-RR and LR and slightly lower concentration of MC-YR. Detected values for Beliche reservoir were below quantification limits.

  12. Data-independent liquid chromatography/mass spectrometry (LC/MS(E)) detection and quantification of the secreted Apium graveolens pathogen defense protein mannitol dehydrogenase.

    PubMed

    Blackburn, Kevin; Cheng, Fang-Yi; Williamson, John D; Goshe, Michael B

    2010-04-15

    Plant cells secrete a wide variety of defense-related proteins into the extracellular space or apoplast in response to pathogen attack. One of these, mannitol dehydrogenase (MTD), is normally a cytoplasmic enzyme whose primary role is the regulation of intracellular levels of the sugar alcohol mannitol in plants. Recent immunological and biochemical evidence, however, suggests that MTD is also secreted into the apoplast in response to pathogen attack, despite lacking a known peptide signal sequence for Golgi-mediated secretion. Because many plant pathogenic fungi secrete mannitol to overcome pathogen-induced generation of reactive oxygen species (ROS) by the plant, extracellular localization of MTD is hypothesized to have a defensive role of catabolizing pathogen-secreted mannitol. In the current study, LC/MS(E) was used to analyze proteins in the secretome of Apium graveolens (celery) following treatment with salicylic acid (SA), an endogenous elicitor of defense responses in plants. Levels of MTD in the secretome of SA-treated celery cell cultures were found to be induced at least 18-fold over secretome samples from cell cultures not exposed to SA. This value is in close agreement with published immunological and biochemical observations. Overall, this report provides the first mass spectrometry identification and quantification measurements supporting the hypothesis that MTD is secreted in response to simulated pathogen attack via a non-classical secretion mechanism. As demonstrated with MTD secretion, LC/MS(E) can be implemented as a discovery-driven MRM-based quantitative approach which can be used to reveal potential post-translational modifications, thus providing a new method in the area of gel-free and label-free proteomic analysis.

  13. Novel approach for the determination of volatile compounds in processed onion by headspace gas chromatography-mass spectrometry (HS GC-MS).

    PubMed

    Colina-Coca, Clara; González-Peña, Diana; Vega, Estela; de Ancos, Begoña; Sánchez-Moreno, Concepción

    2013-01-15

    A novel headspace gas chromatography-mass spectrometry (HS GC-MS) method was developed for analysis of volatile compounds in onion (Allium cepa L. var. cepa, 'Recas'). MS was operated using full scan mode and selective ion monitoring (SIM) mode in order to quantify some specific compounds with increased sensitivity relative to full scan mode. The limits of detection and quantitation ranged from 0.01 to 0.10 μg/g and from 0.02 to 3.83 μg/g fresh weight, respectively, for studied compounds. The procedure allowed the identification of eighteen compounds and quantitation of nine compounds in the volatile fraction of onion, belonging mainly to di-, and trisulfides and aldehydes. These methods were applied to evaluate how high-pressure (HP) as a processing technology affects onion volatile compounds, responsible in part of the onion biological activity. Onion samples were treated at T1: 200 MPa/25°C/5 min, T2: 400 MPa/25°C/5 min and T3: 600 MPa/25°C/5 min (treatments). In addition, the difference among diced, freeze-dried and pulverized onions (groups) was studied, in order to select the process more adequate for better preserving volatile compounds. The results obtained in full scan mode showed that both main factors (group and treatment) had a significant effect (P<0.001). There were also significant differences between groups and treatments for all compounds, being the main effect of group more marked by HS GC-MS using selective ion monitoring (SIM) mode. For 2-methyl 2-pentenal, dimethyl trisulfide, and methyl propyl trisulfide it has been observed an increase in freeze-dried and pulverized onion samples compared with diced samples regardless the HP treatment. However, freeze-drying and pulverization processes affected the stability of propionaldehyde, 1-propanethiol, hexanal, dipropyl disulfide, and dipropyl trisulfide, diminishing their content regardless the HP treatment. HP at 200 and 400 MPa/25°C/5 min were the least detrimental treatments to the total

  14. Quantification and visualization of glutathione S-transferase omega 1 in cells using inductively coupled plasma mass spectrometry (ICP-MS) and fluorescence microscopy.

    PubMed

    Liang, Yong; Jiang, Xin; Tang, Nannan; Yang, Limin; Chen, Haifeng; Wang, Qiuquan

    2015-03-01

    We report a novel activity-based and Cu-free click chemistry (CC) mediated methodology for glutathione S-transferase omega 1 (GSTO1) quantification using species-unspecific isotope dilution inductively coupled plasma mass spectrometry (SUID ICP-MS), in which dibenzylcyclooctyne-modified 2-chloroacetamide (DBCO-ChAcA) was designed and synthesized, meanwhile, as a navigator towards GSTO1 for subsequent N3-DOTA-Eu-tagging via Cu-free CC. Using (153)Eu-SUID ICP-MS coupled with size exclusion chromatography (SEC), the LOD (3σ) of GSTO1 reached 6.9 fmol with an RSD of 2.4% at the 0.1 μM level (n = 5) considering the recovery of GSTO1 on the SEC was 96.5 ± 2.4%. The GSTO1 contents in the cells of human hepatocellular carcinoma C7721 and breast carcinoma MCF-7 as well as normal hepatic C7701 without or with cis-platin administration were quantified to be from 1.2 μg/10,000 cells (n = 3, RSD = 4.5%) corresponding to 1.2 × 10(-2) ng per cell to 4.76 μg/10,000 cells (n = 3, RSD = 2.9%) corresponding to 4.76 × 10(-2) ng per cell. For a comparative study, DBCO-ChAcA-fluor 488-based fluorescence microscopy could not alone visualize GSTO1 in the cells but could together with those from the small SH-containing molecules such as GSH and that from extra N3-fluor 488 in the cells. This activity-based CC-mediated tagging/labeling strategy provided an opportunity for ICP-MS-based targeted protein quantification, and is very much expected to find its applications in biological mechanism study and the subsequent drug design.

  15. Rapid detection by direct analysis in real time-mass spectrometry (DART-MS) of psychoactive plant drugs of abuse: the case of Mitragyna speciosa aka "Kratom".

    PubMed

    Lesiak, Ashton D; Cody, Robert B; Dane, A John; Musah, Rabi A

    2014-09-01

    Mitragyna speciosa, also known commonly as "Kratom" or "Ketum", is a plant with psychoactive properties that have been attributed to the presence of various indole alkaloids such as mitragynine and 7-hydroxymitragynine. M. speciosa use is gaining popularity internationally as a natural and legal alternative to narcotics. As a drug of abuse, its detection and identification are not straightforward, since M. speciosa plant material is not particularly distinctive. Here, we show that direct analysis in real time-mass spectrometry (DART-MS) can be used not only to rapidly identify M. speciosa plant material and distinguish it from other plants, but also to distinguish between M. speciosa plant varieties, based on differences between their chemical profiles. The method is rapid and the analysis expeditious. Plant material such as that found at a crime scene can be analyzed directly with no sample pre-preparation steps. Furthermore, we show that the basis set of principal components that permit characterization of the plant material can be used to positively identify M. speciosa. PMID:25086346

  16. Analysis of Cu, Co, V and Zn in coastal waters of the East China Sea by inductively coupled plasma mass spectrometry (ICP-MS)

    NASA Astrophysics Data System (ADS)

    Yang, Rujun; Ning, Yutong; Zhang, Aibin; Li, Yan; Su, Han

    2016-10-01

    In this study, a simple method for the simultaneous determination of trace metals (Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry (ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L-1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.

  17. Determination of impurities in thoria (ThO 2) using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

    NASA Astrophysics Data System (ADS)

    Alamelu, Devanathan; Choudhary, Ashwini Kumar; Aggarwal, Suresh Kumar

    2010-11-01

    Elemental impurities in nuclear grade thoria were determined using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) employing ArF laser (20 ns, 193 nm, 20 Hz). Three certified standards of thoria, prepared in the Department of Atomic Energy (DAE), India were used for this work. Magnesium was used as an internal standard for quantification in view of its addition during fuel fabrication. The concentrations determined for 16 different elements (Al, B, Cd, Ce, Cu, Dy, Er, Eu, Fe, Gd, Mg, Mn, Mo, Ni, Sb, Sm and V), spanning four orders of magnitude, were within 20% of the certified values in the standards. The methodology is of interest to reduce the analytical effort with regard to dissolution of thoria samples, avoid the production of radioactive liquid waste streams and relatively simple mass spectrum as compared to complex emission spectra in atomic emission spectroscopy (AES) and laser induced breakdown spectroscopy (LIBS). The development and validation of analytical methodologies based on independent physico-chemical principles is of great relevance to characterize the in-house prepared working standards for routine applications.

  18. Multi-residue analysis method for analysis of pharmaceuticals using liquid chromatography-time of flight/mass spectrometry (LC-TOF/MS) in water sample

    NASA Astrophysics Data System (ADS)

    Al-Qaim, Fouad Fadhil; Abdullah, Md Pauzi; Othman, Mohamed Rozali

    2013-11-01

    In this work, a developed method using solid - phase extraction (SPE) followed by liquid chromatography - time of flight mass spectrometry (LC-ESI-TOF/MS) was developed and validated for quantification and confirmation of eleven pharmaceuticals with different therapeutic classes in water samples, Malaysia. These compounds are caffeine (CAF), prazosin (PRZ), enalapril (ENL), carbamazepine (CBZ), nifedipine (NFD), levonorgestrel (LNG), simvastatin (SMV), hydrochlorothiazide (HYD), gliclazide (GLIC), diclofenac-Na (DIC-Na) and mefenamic acid (MEF). LC was performed on a Dionex Ultimate 3000/LC 09115047 (USA) system. Chromatography was performed on a Thermo Scientific C18 (250 mm × 2.1 mm, i.d.: 5μm) column. Several parameters were optimised such as; mobile phase, gradient elution, collision energy and solvent elution for extraction of compounds from water. The recoveries obtained ranged from 30-148 % in river water. Five pharmaceutical compounds were detected in the surface water samples: caffeine, prazosin, enalpril, diclofenac-Na and mefenamic acid. The developed method is precise and accepted recoveries were got. In addition, this method is suitable to identify and quantify trace concentrations of pharmaceuticals in surface water.

  19. Quantification of 11-Carboxy-Delta-9-Tetrahydrocannabinol (THC-COOH) in Meconium Using Gas Chromatography/Mass Spectrometry (GC/MS).

    PubMed

    Peat, Judy; Davis, Brehon; Frazee, Clint; Garg, Uttam

    2016-01-01

    Maternal substance abuse is an ongoing concern and detecting drug use during pregnancy is an important component of neonatal care when drug abuse is suspected. Meconium is the preferred specimen for drug testing because it is easier to collect than neonatal urine and it provides a much broader time frame of drug exposure. We describe a method for quantifying 11-carboxy-delta-9-tetrahydrocannabinol (THC-COOH) in meconium. After adding a labeled internal standard (THC-COOH D9) and acetonitrile, samples are sonicated to release both free and conjugated THC-COOH. The acetonitrile/aqueous layer is removed and mixed with a strong base to hydrolyze the conjugated THC-COOH. The samples are then extracted with an organic solvent mixture as part of a sample "cleanup." The organic solvent layer is discarded and the remaining aqueous sample is acidified. Following extraction with a second organic mixture, the organic layer is removed and concentrated to dryness. The resulting residue is converted to a trimethylsilyl (TMS) derivative and analyzed using gas chromatography/mass spectrometry (GC/MS) in selective ion monitoring (SIM) mode.

  20. Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS)

    SciTech Connect

    Aerosol Dynamics Inc; Aerodyne Research, Inc.,; Tofwerk AG, Thun; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Doug R.; Goldstein, Allen H.

    2011-09-13

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  1. Analysis of caffeic acid derivatives in echinacea extracts by liquid chromatography particle beam mass spectrometry (LC-PB/MS) employing electron impact and glow discharge ionization sources.

    PubMed

    Castro, Joaudimir; Krishna, M V Balarama; Choiniere, John R; Marcus, R Kenneth

    2010-06-01

    A liquid chromatography-particle beam/mass spectrometry (LC-PB/MS) method with electron impact (EI) and glow discharge (GD) ionization sources is presented for the determination of caffeic acid derivatives in echinacea tinctures. In this work, two commercially available echinacea ethanolic extracts were used as the test samples for the separation, identification, and quantification of the caffeic acid derivatives (caffeic acid, chlorogenic acid, cichoric acid, and caftaric acid), which are suggested to have beneficial medicinal properties. Detailed evaluations of the two primary controlling parameters for EI (electron energy and source block temperature) and GD (discharge current and pressure) sources were performed to determine optimal instrument operation conditions. The mass spectra obtained from both ion sources provide clear and simple molecular fragmentation patterns for each of the target analytes. The absolute detection limits for the caffeic acid derivatives were determined to be at subnanogram levels for both the EI and GD sources. The separation of the caffeic acid derivatives in echinacea was accomplished by reversed-phase chromatography using a C(18) column and a gradient elution system of water containing 0.1% trifluoroacetic acid and methanol, with an analysis time of less than 40 min. A standard addition method was employed for the quantification of each of the caffeic acid derivatives in the tincture. PMID:20349350

  2. Determination of the alkylpyrazine composition of coffee using stable isotope dilution-gas chromatography-mass spectrometry (SIDA-GC-MS).

    PubMed

    Pickard, Stephanie; Becker, Irina; Merz, Karl-Heinz; Richling, Elke

    2013-07-01

    A stable isotope dilution analysis based on gas chromatography-mass spectrometry analysis (SIDA-GC-MS) was developed for the quantitative analysis of 12 alkylpyrazines found in commercially available coffee samples. These compounds contribute to coffee flavor. The accuracy of this method was tested by analyzing model mixtures of alkylpyrazines. Comparisons of alkylpyrazine-concentrations suggested that water as extraction solvent was superior to dichloromethane. The distribution patterns of alkylpyrazines in different roasted coffees were quite similar. The most abundant alkylpyrazine in each coffee sample was 2-methylpyrazine, followed by 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, and 2,3,5-trimethylpyrazine, respectively. Among the alkylpyrazines tested, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine revealed the lowest concentrations in roasted coffee. By the use of isotope dilution analysis, the total concentrations of alkylpyrazines in commercially available ground coffee ranged between 82.1 and 211.6 mg/kg, respectively. Decaffeinated coffee samples were found to contain lower amounts of alkylpyrazines than regular coffee samples by a factor of 0.3-0.7, which might be a result of the decaffeination procedure. PMID:23745606

  3. Chemical speciation studies on DU contaminated soils using flow field flow fractionation linked to inductively coupled plasma mass spectrometry (FlFFF-ICP-MS).

    PubMed

    Brittain, S R; Cox, A G; Tomos, A D; Paterson, E; Siripinyanond, A; McLeod, C W

    2012-03-01

    Flow field flow fractionation (FlFFF) in combination with inductively coupled plasma mass spectrometry (ICP-MS) was used to study the chemical speciation of U and trace metals in depleted uranium (DU) contaminated soils. A chemical extraction procedure using sodium pyrophosphate, followed by isolation of humic and fulvic substances was applied to two dissimilar DU contaminated sample types (a sandy soil and a clay-rich soil), in addition to a control soil. The sodium pyrophosphate fractions of the firing range soils (Eskmeals and Kirkcudbright) were found to contain over 50% of the total U (measured after aqua regia digestion), compared to approximately 10% for the control soil. This implies that the soils from the contaminated sites contained a large proportion of the U within more easily mobile soil fractions. Humic and fulvic acid fractions each gave characteristic peak maxima for analytes of interest (Mn, Fe, Cu, Zn, Pb and U), with the fulvic acid fraction eluting at a smaller diameter (approximately 2.1 nm on average) than the humic fraction (approximately 2.4 nm on average). DU in the fulvic acid fraction gave a bimodal peak, not apparent for other trace elements investigated, including natural U. This implies that DU interacts with the fulvic acid fraction in a different way to all other elements studied. PMID:22237634

  4. Identification of volatile butyl rubber thermal-oxidative degradation products by cryofocusing gas chromatography/mass spectrometry (cryo-GC/MS).

    SciTech Connect

    Smith, Jonell Nicole; White, Michael Irvin; Bernstein, Robert; Hochrein, James Michael

    2013-02-01

    Chemical structure and physical properties of materials, such as polymers, can be altered as aging progresses, which may result in a material that is ineffective for its envisioned intent. Butyl rubber formulations, starting material, and additives were aged under thermal-oxidative conditions for up to 413 total days at up to 124 ÀC. Samples included: two formulations developed at Kansas City Plant (KCP) (#6 and #10), one commercially available formulation (#21), Laxness bromobutyl 2030 starting material, and two additives (polyethylene AC-617 and Vanax MBM). The low-molecular weight volatile thermal-oxidative degradation products that collected in the headspace over the samples were preconcentrated, separated, and detected using cryofocusing gas chromatography mass spectrometry (cryo-GC/MS). The majority of identified degradation species were alkanes, alkenes, alcohols, ketones, and aldehydes. Observations for Butyl #10 aged in an oxygen-18 enriched atmosphere (18O2) were used to verify when the source of oxygen in the applicable degradation products was from the gaseous environment rather than the polymeric mixture. For comparison purposes, Butyl #10 was also aged under non-oxidative thermal conditions using an argon atmosphere.

  5. Determination of the alkylpyrazine composition of coffee using stable isotope dilution-gas chromatography-mass spectrometry (SIDA-GC-MS).

    PubMed

    Pickard, Stephanie; Becker, Irina; Merz, Karl-Heinz; Richling, Elke

    2013-07-01

    A stable isotope dilution analysis based on gas chromatography-mass spectrometry analysis (SIDA-GC-MS) was developed for the quantitative analysis of 12 alkylpyrazines found in commercially available coffee samples. These compounds contribute to coffee flavor. The accuracy of this method was tested by analyzing model mixtures of alkylpyrazines. Comparisons of alkylpyrazine-concentrations suggested that water as extraction solvent was superior to dichloromethane. The distribution patterns of alkylpyrazines in different roasted coffees were quite similar. The most abundant alkylpyrazine in each coffee sample was 2-methylpyrazine, followed by 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, and 2,3,5-trimethylpyrazine, respectively. Among the alkylpyrazines tested, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine revealed the lowest concentrations in roasted coffee. By the use of isotope dilution analysis, the total concentrations of alkylpyrazines in commercially available ground coffee ranged between 82.1 and 211.6 mg/kg, respectively. Decaffeinated coffee samples were found to contain lower amounts of alkylpyrazines than regular coffee samples by a factor of 0.3-0.7, which might be a result of the decaffeination procedure.

  6. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the human biomonitoring of non-occupational exposure to the fragrance 2-(4-tert-butylbenzyl)propionaldehyde (lysmeral).

    PubMed

    Pluym, Nikola; Krnac, Dusan; Gilch, Gerhard; Scherer, Max; Leibold, Edgar; Scherer, Gerhard

    2016-08-01

    2-(4-tert-Butylbenzyl)propionaldehyde also known as lysmeral, lilial, or lily aldehyde (CAS No. 80-54-6) is a synthetic odorant mainly used as a fragrance in a variety of consumer products like cleaning agents, fine fragrances, cosmetics, and air fresheners. Due to its broad application in various fields, lysmeral was selected for the development of a biomonitoring method for the quantitative exposure assessment within the frame of the cooperation project of the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) and the German Chemical Industry Association (VCI). A method based on ultra-high pressure liquid chromatography combined with tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of potential biomarkers of lysmeral in human urine samples. Sample cleanup was performed by liquid-liquid extraction (LLE). Quantification was achieved by standard addition using stable isotope-labeled, authentic reference standards. The method is characterized by its robustness, reliability, and excellent sensitivity as proven during method validation according to approved standard guidelines. The following five lysmeral metabolites were identified as potential biomarkers of exposure for lysmeral in human urine samples: lysmerol, lysmerylic acid, hydroxylated lysmerylic acid, tert-butylbenzoic acid (TBBA), and tert-butylhippuric acid (TBHA). The determination of lysmerol required derivatization with 3-nitrophthalic acid anhydride and showed the lowest limit of detection (LOD) and limit of quantification (LOQ) in urine (0.035 and 0.10 μg/L, respectively). LOD and LOQ for the other metabolites were in the range of 0.12-0.15 and 0.36-0.45 μg/L, respectively. Accuracy for all analytes was in the range of 90-110 %. Intra- and inter-day precision was in the range of 5-10 %, except for TBHA, for which the coefficient of variation was unacceptably high (>20 %) and therefore excluded from the method. The

  7. General unknown screening in hair by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).

    PubMed

    Broecker, Sebastian; Herre, Sieglinde; Pragst, Fritz

    2012-05-10

    The retrospective investigation of the exposure to toxic substances by general unknown screening of hair is still a difficult task because of the large number of possible poisons, the low sample amount and the difficult sample matrix. In this study the use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was tested as a promising technique for this purpose. In the optimized procedure, 20mg hair were decontaminated with water and acetone and two times extracted by 18h incubation with 0.5ml of a mixture of methanol/acetonitrile/H(2)O/ammonium formate at 37°C. A mixture of deuterated standards from different drug groups was added for quantification and method control. The united extracts were evaporated to a residue of 0.5ml and 5μl were injected without clean-up for LC-QTOF-MS measurement (instrument Agilent 6530) with positive electrospray ionization and in data dependent acquisition mode. For peak identification the accurate mass data base and spectral library of the authors was used which contains accurate mass CID spectra of more than 2500 and theoretically calculated accurate mass data of more than 7500 toxicologically relevant substances. Validation at the example of 24 illegal drugs, their metabolites and benzodiazepines resulted in limits of detection of 0.003-0.015ng/mg, and limits of quantification of 0.006-0.021ng/mg with good accuracy and intra- and interday reproducibility. The matrix effect by ion suppression/enhancement was 72-107% for basic drugs and 42-75% for benzodiazepines. Yields of the hair extraction above 90% were determined for 59 drugs or metabolites. The method was applied to hair samples from 30 drug fatalities and from 60 death cases with known therapeutic drug intake at life time. Altogether 212 substances were identified with a frequency per drug of 1-40 (mean 4.2) and per case of 2-33 (mean 10.2), between them 35 illegal drug related substances and 154 therapeutic drugs. Comparison with the

  8. Development of a Rapid and Accurate Identification Method for Citrobacter Species Isolated from Pork Products Using a Matrix-Assisted Laser-Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS).

    PubMed

    Kwak, Hye-Lim; Han, Sun-Kyung; Park, Sunghoon; Park, Si Hong; Shim, Jae-Yong; Oh, Mihwa; Ricke, Steven C; Kim, Hae-Yeong

    2015-09-01

    Previous detection methods for Citrobacter are considered time consuming and laborious. In this study, we have developed a rapid and accurate detection method for Citrobacter species in pork products, using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). A total of 35 Citrobacter strains were isolated from 30 pork products and identified by both MALDI-TOF MS and 16S rRNA gene sequencing approaches. All isolates were identified to the species level by the MALDI-TOF MS, while 16S rRNA gene sequencing results could not discriminate them clearly. These results confirmed that MALDI-TOF MS is a more accurate and rapid detection method for the identification of Citrobacter species.

  9. MS Detectors

    SciTech Connect

    Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

    2005-11-01

    Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

  10. Characterization of 4-hydroxy-2-nonenal-modified peptides by liquid chromatography-tandem mass spectrometry using data-dependent acquisition: neutral loss-driven MS3 versus neutral loss-driven electron capture dissociation.

    PubMed

    Rauniyar, Navin; Stevens, Stanley M; Prokai-Tatrai, Katalin; Prokai, Laszlo

    2009-01-15

    Reactive oxygen species generated during oxidative stress can lead to unfavorable cellular consequences, predominantly due to formation of 4-hydroxy-2-nonenal (HNE) during lipid peroxidation. Data-dependent and neutral loss (NL)-driven MS(3) acquisition have been reported for the identification of HNE adducts by mass spectrometry-based proteomics. However, the limitation associated with this method is the ambiguity in correct assignment of the HNE modification site when more than one candidate site is present as MS(3) is triggered on the neutral loss ion. We introduce NL-triggered electron capture dissociation tandem mass spectrometry (NL-ECD-MS/MS) for the characterization of HNE-modification sites in peptides. With this method performed using a hybrid linear ion trap-Fourier transform ion cyclotron resonance (FTICR) mass spectrometer, ECD in the FTICR unit of the instrument is initiated on precursor ions of peptides showing the neutral loss of 156 Da corresponding to an HNE molecule in the prescan acquired via collision-induced dissociation tandem mass spectrometry in the linear ion trap. In addition to manifold advantages associated with the ECD method of backbone fragmentation, including extensive sequence fragments, ECD tends to retain the HNE group during MS/MS of the precursor ion, facilitating the correct localization of the modification site. The results also suggest that predisposition of a peptide molecular ion to lose HNE during collision-induced dissociation-based fragmentation is independent of its charge state (2+ or 3+). In addition, we have demonstrated that coupling of solid-phase enrichment of HNE-modified peptides facilitates the detection of this posttranslational modification by NL-driven strategies for low-abundance proteins that are susceptible to substoichiometric carbonylation during oxidative stress.

  11. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  12. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  13. Metallomics approach to trace element analysis in ustilago maydis using cellular fractionation, atomic absorption spectrometry, and size exclusion chromatography with ICP-MS detection.

    PubMed

    Muñoz, Alma Hortensia Serafin; Kubachka, Kevin; Wrobel, Kazimierz; Corona, Felix Gutierrez; Yathavakilla, Santha K V; Caruso, Joseph A; Wrobel, Katarzyna

    2005-06-29

    Huitlacoche is the ethnic name of the young fruiting bodies of Ustilago maydis, a common parasite of maize. In Mexico and other Latin American countries, this fungus has been traditionally appreciated as a local delicacy. In this work a metallomics approach was used with the determination of eight elements in huitlacoche by electrothermal atomic absorption spectrometry as one facet of this approach. The results obtained indicated relatively lower concentrations of commonly analyzed metals, as referred to the data reported for other mushroom types. This effect was ascribed to different accessibilities of elements, depending on fungus substrate (lower from plant than from soil). Subcellular fractionation was accomplished by centrifugation of cell homogenates suspended in Tris-HCl buffer. Recoveries of the fractionation procedure were in the range of 71-103%. For six elements (Cr, Cu, Fe, Mn, Ni, and Pb), the mean relative contributions in cytosol, cell walls, and mixed membrane fraction were 50.7, 48.2, and 1.1% respectively. To attain the molecular weight distribution of compounds containing target elements as an additional aspect of the metallomics approach, the fungus extract (1% sodium dodecyl sulfate in Tris-HCl, 30 mmol L(-)(1), pH 7.0) was analyzed by size exclusion chromatography with UV and ICP-MS detection. With spectrophotometric detection (280 nm), the elution of high molecular weight compounds was observed in the form of one peak (MW > 10 kDa), and several lower peaks appeared at higher retention times (MW < 10 kDa). On ICP-MS chromatograms, a coelution of (59)Co, (63)Cu, (57)Fe, (202)Hg, (60)Ni, and (80)Se with the first peak on the UV chromatogram was clearly observed, indicating that a fraction of each element incorporated with high molecular weight compounds (12.7, 19.8, 33.7, 100, 19.4, and 45.8%, respectively, based on the peak area measurements). From a comparison of (80)Se and (33)S chromatograms (for sulfur analysis, the extract was obtained in

  14. Investigation on pharmacokinetics, tissue distribution and excretion of a novel platinum anticancer agent in rats by inductively coupled plasma mass spectrometry (ICP-MS).

    PubMed

    Zhao, Jie; Wen, Yanli; Zhang, Wei; Zhao, Di; Fan, Ali; Zhang, Yongjie; Deng, Shuhua; Wang, Xin; Liu, Qingwang; Lu, Yang; Wang, Zhimei; Gou, Shaohua; Chen, Xijing

    2014-08-01

    1. DN604 is a new platinum agent with encouraging anticancer activity. The present study was to explore the pharmacokinetic profiles, distribution and excretion of platinum in Sprague-Dawley rats after intravenous administration of DN604. A sensitive and selective inductively coupled plasma mass spectrometry (ICP-MS) method was established for determination of platinum in biological specimens. The pharmacokinetic parameters were calculated by a non-compartmental method. 2. The area under concentration-time curve AUC0-t and AUC0-∞ for platinum originating from DN604 at 10 mg/kg were 25.15 ± 1.29 and 28.72 ± 1.04 μg/hml, respectively. The mean residence time MRT was 36.59 ± 6.65 h. The volume of distribution Vz was 11.42 ± 2.49 l/kg and clearance CL was 0.18 ± 0.01 l/h/kg. In addition, the elimination half-life T1/2z was 44.83 ± 9.75 h. After intravenous administration of DN604, platinum was extensively distributed in most of tested tissues except brain. The majority of platinum excreted via urine, and its accumulative excretion ratio during the period of 120 h was 63.5% ± 7.7% for urine, but only 6.94% ± 0.11% for feces. 3. The satisfactory half-life, wide distribution and high excretion made this novel platinum agent worthy of further research and development.

  15. Xylem sap collection and extraction methodologies to determine in vivo concentrations of ABA and its bound forms by gas chromatography-mass spectrometry (GC-MS)

    PubMed Central

    2012-01-01

    Background Accurate quantification of xylem sap ABA concentrations is important to underpin models of root-to-shoot ABA signalling to predict the physiological effects of soil drying. Growing tomato plants in a whole plant pressure chamber allowed sequential xylem sap collection from a detached leaf, the petiole stub of an otherwise intact plant and finally the de-topped root system of the same plant, to determine the impact of xylem sap sampling methodology on xylem ABA concentration. Since xylem sap can contain bound forms of ABA, a novel gas chromatography-mass spectrometry (GC-MS) procedure was developed to chemically separate free ABA from two in planta bound ABA forms known as Adducts I and II and ABA-glucose-ester (ABA-GE). Results Xylem sap ABA concentrations were highly dependent on the sampling methodology used: the highest concentrations were detected in sap collected by applying an overpressure to detached leaves following the measurement of leaf water potential. Irrespective of xylem sap source, the wild-type cultivars Ailsa Craig and Rheinlands Ruhm had higher free ABA concentrations than a range of ABA-deficient mutants (notabilis, flacca and sitiens). However, in the mutants, concentrations of bound forms of ABA were similar to wild-type plants, and similar to free ABA concentrations. Conclusions Although xylem concentrations of these bound ABA forms and ABA-GE suggest they have a limited physiological impact on ABA homeostasis in tomato, the methods developed here will allow a more complete understanding of ABA biochemistry and root-to-shoot signalling in species known to have higher concentrations of these compounds. PMID:22439865

  16. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    NASA Astrophysics Data System (ADS)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  17. Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.

    PubMed

    Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

    2014-08-13

    Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS.

  18. Application of fast ultrasound water-bath assisted enzymatic hydrolysis--high performance liquid chromatography-inductively coupled plasma-mass spectrometry procedures for arsenic speciation in seafood materials.

    PubMed

    Moreda-Piñeiro, Antonio; Moreda-Piñeiro, Jorge; Herbello-Hermelo, Paloma; Bermejo-Barrera, Pilar; Muniategui-Lorenzo, Soledad; López-Mahía, Purificación; Prada-Rodríguez, Darío

    2011-09-28

    Enzymatic hydrolysis of seafood materials for isolating arsenic species (As(III), As(V), DMA and AsB) has been successfully performed by assisting the procedure with ultrasound energy (35 kHz) supplied by an ultrasound water-bath. The use of pepsin, as a proteolytic enzyme, under optimized operating conditions (pH 3.0, temperature 40°C, enzyme to sample ratio of 0.3) led to an efficient assistance of the enzymatic process in a short period of time (from 4.0 to 30 min). The enzymatic extract was then subjected to a clean-up procedure based on ENVI-Carb™ solid phase extraction (SPE). An optimized anion exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) permitted the fast separation (less than 15 min) of six different arsenic species (arsenite, As(III); arsenate, As(V); dimethylarsinic acid, DMA; and arsenobetaine, AsB; as well as monomethylarsonic acid, MMA; and arsenocholine, AsC) in a single run. Relative standard deviations (n=11) of the over-all procedure were 7% for AsB and DMA, 11% for As(III) and 9% for MMA. HPLC-ICP-MS determinations were performed using aqueous calibrations covering arsenic concentrations of 0, 5, 10, 25, 100 and 200 μg L(-1) (expressed as arsenic) for As(III), As(V), MMA, DMA and AsC; and 0, 125, 250, 500, 750, 1000 and 2000 μg L(-1) (expressed as arsenic) for AsB. Germanium (5 μg L(-1)) was used as an internal standard. Analytical recoveries from the anion exchange column varied from 96 to 105% (enzymatic digests spiked with low target concentrations), from 97 to 104% (enzymatic digests spiked with intermediate target concentrations), and from 98 to 103% (enzymatic digests spiked with high target concentrations). The developed method was successfully applied to two certified reference materials (CRMs), DORM-2 and BCR 627, which offer certified AsB and DMA contents, and also to different seafood samples (mollusks, white fish and cold water fish). Good agreement

  19. Sensitive Detection of Aromatic Hydrophobic Compounds in Water and Perfluorooctane Sulfonate in Human Serum by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry (SALDI-MS) with Amine Functionalized Graphene-Coated Cobalt Nanoparticles

    PubMed Central

    Nakai, Keisuke; Kawasaki, Hideya; Yamamoto, Atsushi; Arakawa, Ryuichi; Grass, Robert N.; Stark, Wendelin J.

    2014-01-01

    In this article, we describe the application of surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) with the use of amine functionalized graphene-coated cobalt nanoparticles (CoC–NH2 nanoparticles) to analyse aromatic hydrophobic compounds that are known environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP). Our results demonstrated that SALDI-MS can detect PCP, anthracene, and pyrene in water. In particular, the CoC–NH2 nanoparticles proved to be an efficient means of capturing PCP in water because of the high adsorption capacity of the nanoparticles for PCP, which resulted in a detectability of 100 ppt. Furthermore, the CoC–NH2 nanoparticles also functioned as an adsorbent for solid-phase extraction of perfluorooctane sulfonate (PFOS) from human serum, displaying good performance with a detectability of 10 ppb by SALDI-MS. PMID:26819871

  20. Sensitive Detection of Aromatic Hydrophobic Compounds in Water and Perfluorooctane Sulfonate in Human Serum by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry (SALDI-MS) with Amine Functionalized Graphene-Coated Cobalt Nanoparticles.

    PubMed

    Nakai, Keisuke; Kawasaki, Hideya; Yamamoto, Atsushi; Arakawa, Ryuichi; Grass, Robert N; Stark, Wendelin J

    2014-01-01

    In this article, we describe the application of surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) with the use of amine functionalized graphene-coated cobalt nanoparticles (CoC-NH2 nanoparticles) to analyse aromatic hydrophobic compounds that are known environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP). Our results demonstrated that SALDI-MS can detect PCP, anthracene, and pyrene in water. In particular, the CoC-NH2 nanoparticles proved to be an efficient means of capturing PCP in water because of the high adsorption capacity of the nanoparticles for PCP, which resulted in a detectability of 100 ppt. Furthermore, the CoC-NH2 nanoparticles also functioned as an adsorbent for solid-phase extraction of perfluorooctane sulfonate (PFOS) from human serum, displaying good performance with a detectability of 10 ppb by SALDI-MS.

  1. Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): species-level identification of clinical isolates of Exophiala dermatitidis.

    PubMed

    Kondori, Nahid; Erhard, Marcel; Welinder-Olsson, Christina; Groenewald, Marizeth; Verkley, Gerard; Moore, Edward R B

    2015-01-01

    Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxon- specific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35(T)) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods. PMID:25790495

  2. [Simultaneous determination of multi-organotin compounds in seawater by liquid-liquid extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry].

    PubMed

    Yu, Zhen-Hua; Jing, Miao; Wang, Xiao-Ru; Chen, Deng-Yun; Huang, Yan-Liang

    2009-10-01

    The hyphenated technique of high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was applied to the simultaneous determination of five organotin compounds (trimethyltin, dibutyltin, tributyltin, diphenyltin and triphenyltin) in seawater samples. Agilent TC-C18 column was used for the separation, the mobile phase of HPLC was CH3CN : H2O : CH3COOH = 65 : 23 : 12 (phi3), 0.05% TEA, and pH value was adjusted to 3.0 by diluent ammonia. The flow rate was 0.6 mL x min(-1). Five mixed organotin compounds in a mix standard solution from 100 to 0.5 microg x L(-1) were applied for the method assessment. The experimental results indicate that the correlation coefficient of calibration curves (R2) for each organotin compound was over 0.998 and the detection limits of the five organotin compounds were lower than 3 ng x L(-1). Different mixed organic solvents including dichloromethane or toluene were used for extraction of organotin and the extraction condition of organotin from seawater was optimized. The 100 mL seawater acidized by hydrochloric acid was extracted by 10 mL carbon dichloride (CH2 Cl2) with 2% tropolone for 10 min twice. Extracted organic solvents were mixed and blown to one drop by nitrogen with the rate of 1.7 mL x min(-1), then 1 mL acetonitrile was added to the drop for redissolving the organotin compounds. Finally, the mixed redissolution was filtered by 0.22 microm organic filter membrane before analysis. It was found that the only organotin compound in seawater was triphenyltin (TPHT) and the content was 53.2 ng x L(-1). The recoveries test from the standard addition for diphenyltin (DPHT), dibutyltin (DBT), tributyltin (TBT) and triphenyltin (TPHT) were over 80%. However, the recovery for trimethyltin (TMT) was relatively low and the value was 50%. The reason might be attributed to the decomposition or adsorption of those compounds during the extraction procedure. Further study on this subject is in

  3. Sensomics analysis of key hazelnut odorants (Corylus avellana L. 'Tonda Gentile') using comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC×GC-TOF-MS).

    PubMed

    Kiefl, Johannes; Pollner, Gwendola; Schieberle, Peter

    2013-06-01

    Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) has been used a few times to identify and quantitate single aroma-active compounds, but the capability of this technique to monitor a complete set of key odorants evoking the aroma of a given food in one run has not been exploited so far. A fast, multiodorant analysis using GC×GC-TOF-MS in combination with stable isotope dilution assays (SIDA) was developed to quantitate the entire set of aroma compounds, the sensometabolome, of raw and roasted hazelnuts ( Corylus avellana L. 'Tonda Gentile') previously established by GC-olfactometry. The capability of the method to evaluate the aroma contribution of each sensometabolite was evaluated by introducing a new term, the limit of odor activity value (LOAV), indicating whether a given aroma compound can be determined down to an odor activity value (OAV) of 1 (odor activity value = ratio of concentration to odor threshold). The advantage of the new method was proven by comparing the performance parameters with a traditional one-dimensional approach using GC-ion trap mass-spectrometry (GC-IT-MS). The results showed that the detector linearity and sensitivity of GC×GC-TOF-MS was on average higher by a factor of 10 compared to GC-IT-MS, thus enabling the quantitation of the aroma relevant amounts of 22 key odorants of hazelnuts in one run of the 30 aroma-active compounds. Seven novel isotopically labeled internal standards were synthesized to meet the analytical requirements defined by electron impact ionization in TOF-MS, that is, to keep the label. On the basis of the quantitative results obtained, it was possible to closely mimic the aroma of raw and roasted 'Tonda Gentile' hazelnuts by preparing an aroma recombinate containing the key odorants at their natural concentrations occurring in the nuts.

  4. Sensomics analysis of key hazelnut odorants (Corylus avellana L. 'Tonda Gentile') using comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC×GC-TOF-MS).

    PubMed

    Kiefl, Johannes; Pollner, Gwendola; Schieberle, Peter

    2013-06-01

    Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) has been used a few times to identify and quantitate single aroma-active compounds, but the capability of this technique to monitor a complete set of key odorants evoking the aroma of a given food in one run has not been exploited so far. A fast, multiodorant analysis using GC×GC-TOF-MS in combination with stable isotope dilution assays (SIDA) was developed to quantitate the entire set of aroma compounds, the sensometabolome, of raw and roasted hazelnuts ( Corylus avellana L. 'Tonda Gentile') previously established by GC-olfactometry. The capability of the method to evaluate the aroma contribution of each sensometabolite was evaluated by introducing a new term, the limit of odor activity value (LOAV), indicating whether a given aroma compound can be determined down to an odor activity value (OAV) of 1 (odor activity value = ratio of concentration to odor threshold). The advantage of the new method was proven by comparing the performance parameters with a traditional one-dimensional approach using GC-ion trap mass-spectrometry (GC-IT-MS). The results showed that the detector linearity and sensitivity of GC×GC-TOF-MS was on average higher by a factor of 10 compared to GC-IT-MS, thus enabling the quantitation of the aroma relevant amounts of 22 key odorants of hazelnuts in one run of the 30 aroma-active compounds. Seven novel isotopically labeled internal standards were synthesized to meet the analytical requirements defined by electron impact ionization in TOF-MS, that is, to keep the label. On the basis of the quantitative results obtained, it was possible to closely mimic the aroma of raw and roasted 'Tonda Gentile' hazelnuts by preparing an aroma recombinate containing the key odorants at their natural concentrations occurring in the nuts. PMID:23663170

  5. Rapid identification of betacyanins from Amaranthus tricolor, Gomphrena globosa, and Hylocereus polyrhizus by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS).

    PubMed

    Cai, Yi-Zhong; Xing, Jie; Sun, Mei; Corke, Harold

    2006-09-01

    Natural betacyanins have attracted great attention as food colorants and potential antioxidants. Matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS) is a new and powerful technique for the identification of low molecular weight compounds. This study is the first to employ MALDI-QIT-TOF MS to rapidly identify, within a few minutes, a great number of betacyanins in crude extracts from Amaranthus tricolor seedlings, Gomphrena globosa flowers, and Hylocereus polyrhizus fruits. The fresh crude extract samples without any purification were directly used for MALDI-QIT-TOF MS analysis with 2,5-dihydroxybenzoic acid as a matrix. The MS2 and MS3 spectrometric data acquired could provide important characteristic information for structural elucidation of the betacyanins. Fourteen free and acylated betacyanins, belonging to amaranthin-type, betanin-type, and gomphrenin-type betacyanins, respectively, were identified. However, the related isomers should be differentiated with the aid of HPLC.

  6. Identification of Clinical Streptococcus pneumoniae Isolates among other Alpha and Nonhemolytic Streptococci by Use of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System

    PubMed Central

    Segonds, Christine; Prere, Marie-Françoise; Marty, Nicole; Oswald, Eric

    2013-01-01

    Discrimination between Streptococcus pneumoniae and its close relatives of the viridans group is a common difficulty in matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry-based identification. In the present study, the performances of the Vitek MS MALDI-TOF mass spectrometry system were assessed using 334 pneumococci, 166 other S. mitis group streptococci, 184 non-S. mitis group streptococci, and 19 related alpha- and nonhemolytic aerobic Gram-positive catalase-negative coccal isolates. Pneumococci had been identified by means of optochin susceptibility and bile solubility or serotyping, and other isolates mainly by use of RapidID32 Strep strips. In case of discordant or low-discrimination results, genotypic methods were used. The sensitivity of the Vitek MS for the identification of S. pneumoniae was 99.1%, since only three bile-insoluble isolates were misidentified as Streptococcus mitis/Streptococcus oralis. Conversely, two optochin-resistant pneumococci were correctly identified (specificity, 100%). Three Streptococcus pseudopneumoniae isolates were also correctly identified. Among nonpneumococcal isolates, 90.8% (n = 335) were correctly identified to the species or subspecies level and 2.4% (n = 9) at the group level. For the remaining 25 isolates, the Vitek MS proposed a bacterial species included in the list of possible species suggested by genotypic methods, except for 4 isolates which were not identified due to the absence of the species in the database. According to our study, the Vitek MS displays performance similar to that of the optochin susceptibility test for routine identification of pneumococcal isolates. Moreover, the Vitek MS is efficient for the identification of other viridans group streptococci and related isolates, provided that the species are included in the database. PMID:23576536

  7. 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. PMID:26526911

  8. 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.

  9. Determination of vitamins D2 and D3 in selected food matrices by online high-performance liquid chromatography-gas chromatography-mass spectrometry (HPLC-GC-MS).

    PubMed

    Nestola, Marco; Thellmann, Andrea

    2015-01-01

    An online normal-phase liquid chromatography-gas chromatography-mass spectrometry (HPLC-GC-MS) method was developed for the determination of vitamins D2 and D3 in selected food matrices. Transfer of the sample from HPLC to GC was realized by large volume on-column injection; detection was performed with a time-of-flight mass spectrometer (TOF-MS). Typical GC problems in the determination of vitamin D such as sample degradation or sensitivity issues, previously reported in the literature, were not observed. Determination of total vitamin D content was done by quantitation of its pyro isomer based on an isotopically labelled internal standard (ISTD). Extracted ion traces of analyte and ISTD showed cross-contribution, but non-linearity of the calibration curve was not determined inside the chosen calibration range by selection of appropriate quantifier ions. Absolute limits of detection (LOD) and quantitation (LOQ) for vitamins D2 and D3 were calculated as approximately 50 and 150 pg, respectively. Repeatability with internal standard correction was below 2 %. Good agreement between quantitative results of an established high-performance liquid chromatography with UV detection (HPLC-UV) method and HPLC-GC-MS was found. Sterol-enriched margarine was subjected to HPLC-GC-MS and HPLC-MS/MS for comparison, because HPLC-UV showed strong matrix interferences. HPLC-GC-MS produced comparable results with less manual sample cleanup. In summary, online hyphenation of HPLC and GC allowed a minimization in manual sample preparation with an increase of sample throughput.

  10. Comparative evaluation of two matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems, Vitek MS and Microflex LT, for the identification of Gram-positive cocci routinely isolated in clinical microbiology laboratories.

    PubMed

    Lee, Miae; Chung, Hae-Sun; Moon, Hee-Won; Lee, Sun Hwa; Lee, Kyungwon

    2015-06-01

    We evaluated the performance of two MALDI-TOF MS systems for the identification of clinically important Gram-positive cocci. Vitek MS and Microflex LT correctly identified 97.2% and 94.7%, respectively. Both systems offer reliable and rapid identification of clinically important Gram-positive cocci isolated in clinical laboratories, including staphylococci, streptococci, and enterococci. Expanding the databases, especially of coagulase-negative staphylococci and viridans streptococci, would enhance performance.

  11. Pediatric MS

    MedlinePlus

    ... of the oral medications in the pediatric population. Network of Pediatric MS Centers The National MS Society ... MS Study Group (2004) and established a nationwide network of six Pediatric MS Centers of Excellence (2006) ...

  12. Online Capillary IsoElectric Focusing-ElectroSpray Ionization Mass Spectrometry (CIEF-ESI MS) in Glycerol-Water Media for the Separation and Characterization of Hydrophilic and Hydrophobic Proteins.

    PubMed

    Mokaddem, Meriem; d'Orlyé, Fanny; Varenne, Anne

    2016-01-01

    Capillary isoelectric focusing (CIEF) is a high-resolution technique for the separation of ampholytes, such as proteins, according to their isoelectric point. CIEF coupled online with MS is regarded as a promising alternative to 2-D PAGE for fast proteome analysis with high-resolving capabilities and enhanced structural information without the drawbacks of conventional slab-gel electrophoresis. However, online coupling has been rarely described, as it presents some difficulties. A new methodology for the online coupling of CIEF with electrospray ionization mass spectrometry (ESI-MS) has been developed in glycerol-water media. This new integrated methodology provides a mean for the characterization of a large number of hydrophilic and hydrophobic proteins. PMID:27473481

  13. Proteome-based bacterial identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS): A revolutionary shift in clinical diagnostic microbiology.

    PubMed

    Nomura, Fumio

    2015-06-01

    Rapid and accurate identification of microorganisms, a prerequisite for appropriate patient care and infection control, is a critical function of any clinical microbiology laboratory. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a quick and reliable method for identification of microorganisms, including bacteria, yeast, molds, and mycobacteria. Indeed, there has been a revolutionary shift in clinical diagnostic microbiology. In the present review, the state of the art and advantages of MALDI-TOF MS-based bacterial identification are described. The potential of this innovative technology for use in strain typing and detection of antibiotic resistance is also discussed. This article is part of a Special Issue entitled: Medical Proteomics.

  14. 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. PMID:25621437

  15. Comparison of the Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of mycobacteria using simplified protein extraction protocols.

    PubMed

    Mather, Cheryl A; Rivera, Sheila F; Butler-Wu, Susan M

    2014-01-01

    Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been described as a fast and inexpensive method for the identification of mycobacteria. Although mycobacteria require extraction prior to MALDI-TOF MS analysis, previously published protocols have been relatively complex, involving significant hands-on time and materials not often found in the clinical laboratory. In this study, we tested two simplified protein extraction protocols developed at the University of Washington (UW) and by bioMérieux (BMX) for use with two different mass spectrometry platforms (the Bruker MALDI Biotyper and the bioMérieux Vitek MS, respectively). Both extraction protocols included vortexing with silica beads in the presence of ethanol. The commercial Bruker database was also augmented with an in-house database composed of 123 clinical Mycobacterium strains. A total of 198 clinical strains, representing 18 Mycobacterium species, were correctly identified to the species level 94.9% of the time when extracted using the UW protocol and compared to the augmented database. The BMX protocol and Vitek MS system resulted in correct species-level identifications for 94.4% of these strains. In contrast, only 79.3% of the strains were identified to the species level by the nonaugmented Bruker database, although the use of a lower identification score threshold (≥1.7) increased the identification rate to 93.9%, with two misidentifications that were unlikely to be clinically relevant. The two simplified protein extraction protocols described in this study are easy to use for identifying commonly encountered Mycobacterium species. PMID:24172150

  16. Mass spectrometry and NMR spectroscopy: modern high-end detectors for high resolution separation techniques--state of the art in natural product HPLC-MS, HPLC-NMR, and CE-MS hyphenations.

    PubMed

    Seger, Christoph; Sturm, Sonja; Stuppner, Hermann

    2013-07-01

    Current natural product research is unthinkable without the use of high resolution separation techniques as high performance liquid chromatography or capillary electrophoresis (HPLC or CE respectively) combined with mass spectrometers (MS) or nuclear magnetic resonance (NMR) spectrometers. These hyphenated instrumental analysis platforms (CE-MS, HPLC-MS or HPLC-NMR) are valuable tools for natural product de novo identification, as well as the authentication, distribution, and quantification of constituents in biogenic raw materials, natural medicines and biological materials obtained from model organisms, animals and humans. Moreover, metabolic profiling and metabolic fingerprinting applications can be addressed as well as pharmacodynamic and pharmacokinetic issues. This review provides an overview of latest technological developments, discusses the assets and drawbacks of the available hyphenation techniques, and describes typical analytical workflows.

  17. Reduction of measurement uncertainty by experimental design in high-order (double, triple, and quadruple) isotope dilution mass spectrometry: application to GC-MS measurement of bromide.

    PubMed

    Pagliano, Enea; Mester, Zoltán; Meija, Juris

    2013-03-01

    Since its introduction a century ago, isotope dilution analysis has played a central role in developments of analytical chemistry. This method has witnessed many elaborations and developments over the years. To date, we have single, double, and even triple isotope dilution methods. In this manuscript, we summarize the conceptual aspects of isotope dilution methods and introduce the quadruple dilution and the concept of exact matching triple and quadruple dilutions. The comparison of isotope dilution methods is performed by determination of bromide ions in groundwater using novel ethyl-derivatization chemistry in conjunction with GC/MS. We show that the benefits of higher-order isotope dilution methods are countered with a greater need for careful experimental design of the isotopic blends. Just as for ID(2)MS, ID(3)MS and ID(4)MS perform best when the isotope ratio of one sample/spike blend is matched with that of a standard/spike blend (exact matching).

  18. Reduction of measurement uncertainty by experimental design in high-order (double, triple, and quadruple) isotope dilution mass spectrometry: application to GC-MS measurement of bromide.

    PubMed

    Pagliano, Enea; Mester, Zoltán; Meija, Juris

    2013-03-01

    Since its introduction a century ago, isotope dilution analysis has played a central role in developments of analytical chemistry. This method has witnessed many elaborations and developments over the years. To date, we have single, double, and even triple isotope dilution methods. In this manuscript, we summarize the conceptual aspects of isotope dilution methods and introduce the quadruple dilution and the concept of exact matching triple and quadruple dilutions. The comparison of isotope dilution methods is performed by determination of bromide ions in groundwater using novel ethyl-derivatization chemistry in conjunction with GC/MS. We show that the benefits of higher-order isotope dilution methods are countered with a greater need for careful experimental design of the isotopic blends. Just as for ID(2)MS, ID(3)MS and ID(4)MS perform best when the isotope ratio of one sample/spike blend is matched with that of a standard/spike blend (exact matching). PMID:23371530

  19. Measurement of elemental speciation by liquid chromatography -- inductively coupled plasma mass spectrometry (LC-ICP-MS) with the direct injection nebulizer (DIN)

    SciTech Connect

    Shum, S.

    1993-05-01

    This thesis is divided into 4 parts: elemental speciation, speciation of mercury and lead compounds by microbore column LC-ICP-MS with direct injection nebulization, spatially resolved measurements of size and velocity distributions of aerosol droplets from a direct injection nebulizer, and elemental speciation by anion exchange and size exclusion chromatography with detection by ICP-MS with direct injection nebulization. Tabs, figs, refs.

  20. Simultaneous TG/DSC (thermogravimetry/differential scanning calorimetry) and TG/MS (thermogravimetry/mass spectrometry) analyses of polymeric and energetic materials

    SciTech Connect

    Whitaker, R B; Brown, C R; Chang, C; McDaniel, J A; Shell, T L

    1987-01-01

    The utility of simultaneous thermal analysis techniques, such as TG/DSC and TG/MS, has been demonstrated for both energetic and polymeric materials. TG/DSC can assist in elucidating reaction mechanisms and determining weight losses for endothermic transitions which precede decomposition of energetic materials. The endothermic and exothermic nature of decomposition processes can be defined by TG/DSC and the decomposition products identified by TG/MS.

  1. Analysis of sphingolipids in potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) by reversed phase high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS).

    PubMed

    Bartke, Nana; Fischbeck, Anne; Humpf, Hans-Ulrich

    2006-12-01

    Ceramides and glucocerebrosides of potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) were analyzed using RP-HPLC-ESI-MS/MS. Ceramides and glucocerebrosides containing the three different long-chain bases 4,8-sphingadienine (d18:2(delta4,delta8)), 4-hydroxy-8-sphingenine (t18:1(delta8)), and 8-sphingenine (d18:1(delta8)) acylated to saturated and unsaturated hydroxy- and nonhydroxy fatty acids with 16-26 carbon atoms were detected. For ceramides and glucocerebrosides 4,8-sphingadienine (d18:2(delta4,delta8)) was found as the major long-chain base, with lesser amounts of 4-hydroxy-8-sphingenine (t18:1(delta8)) and 8-sphingenine (d18:1(delta8)). 2-(Alpha-)hydroxypalmitic acid (C16:0h) was the major fatty acid, which was found to be acylated to the long-chain bases. For quantification of these compounds, an RP-HPLC-ESI-MS/MS method with an "echo-peak"-technique simulating internal standard injection was developed. The analyzed samples of potatoes and sweet potatoes showed amounts of approximately 0.1-8 microg/kg single ceramides and amounts up to 500 microg/kg glucocerebrosides, with C16:0h-glucosyl-4,8-sphingadienine as the major component.

  2. Analysis of sphingolipids in potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) by reversed phase high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS).

    PubMed

    Bartke, Nana; Fischbeck, Anne; Humpf, Hans-Ulrich

    2006-12-01

    Ceramides and glucocerebrosides of potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) were analyzed using RP-HPLC-ESI-MS/MS. Ceramides and glucocerebrosides containing the three different long-chain bases 4,8-sphingadienine (d18:2(delta4,delta8)), 4-hydroxy-8-sphingenine (t18:1(delta8)), and 8-sphingenine (d18:1(delta8)) acylated to saturated and unsaturated hydroxy- and nonhydroxy fatty acids with 16-26 carbon atoms were detected. For ceramides and glucocerebrosides 4,8-sphingadienine (d18:2(delta4,delta8)) was found as the major long-chain base, with lesser amounts of 4-hydroxy-8-sphingenine (t18:1(delta8)) and 8-sphingenine (d18:1(delta8)). 2-(Alpha-)hydroxypalmitic acid (C16:0h) was the major fatty acid, which was found to be acylated to the long-chain bases. For quantification of these compounds, an RP-HPLC-ESI-MS/MS method with an "echo-peak"-technique simulating internal standard injection was developed. The analyzed samples of potatoes and sweet potatoes showed amounts of approximately 0.1-8 microg/kg single ceramides and amounts up to 500 microg/kg glucocerebrosides, with C16:0h-glucosyl-4,8-sphingadienine as the major component. PMID:17103377

  3. QuEChERS-based purification method coupled to ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to determine six quaternary ammonium compounds (QACs) in dairy products.

    PubMed

    Xian, Yanping; Dong, Hao; Wu, Yuluan; Guo, Xindong; Hou, Xiangchang; Wang, Bin

    2016-12-01

    QuEChERS-based purification coupled with UPLC-MS/MS method, was developed for six quaternary ammonium compounds (QACs) determination in dairy products. Powder samples were firstly dispersed by water. Protein in liquid milk was precipitated and sample solution was extracted by acetonitrile. QuEChERS-based purification was used to purify the solution. QACs were finally separated by HILIC column and detected in MRM mode of MS/MS under ESI(+). The stable isotope benzyl-2,3,4,5,6-d5-dimethyltetradecylammonium bromide (C14-BAC-d5) was used as an internal standard. This method was validated in terms of linearity, sensitivity, precision, accuracy. Linear relations were favorable for QACs over the selected concentration ranges of 0.2-50μg/L, with correlation coefficients greater than 0.999. The limits of detection (LODs) were in the range of 0.4-14.5μg/kg. Recoveries were between 91.2% and 115% with RSDs of 2.8-7.5% for intra-day precision and 3.7-6.7% for inter-day precision. This validated method was successfully applied to determine the QACs concentrations in dairy products. PMID:27374511

  4. Determination of steroidal oestrogens in tap water samples using solid-phase extraction on a molecularly imprinted polymer sorbent and quantification with gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Zacs, D; Perkons, I; Bartkevics, V

    2016-07-01

    An analytical method was established and validated for the analysis of steroidal oestrogens in tap water samples. Gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) were used for the identification/quantification of selected compounds and the analytical performance of these techniques was evaluated. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) with a molecularly imprinted polymer (MIP) stationary phase that was highly selective for oestrogens were used for the extraction of 100-mL aliquots of water samples. The recoveries of analytes with the described methods ranged from 92 to 114 %, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 2.1 to 15.2 % (n = 5). It was concluded that SPE with MIP that was highly selective for oestrogens in combination with GC-HRMS detection is more preferable for the analysis of oestrogens in tap water samples. The typical oestrogen, 17β-estradiol (17β-E2), was detected above the method limit of quantification (m-LOQ) in 5 of 14 analysed tap water samples at concentrations from 0.09 to 0.15 ng L(-1). Despite that 17α-ethynylestradiol (17α-EE2) was not quantified in this study above m-LOQ, the presence of this chemical was qualitatively confirmed in some of the analysed samples.

  5. Anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma-isotope dilution-time-of-flight mass spectrometry for speciation analysis of metal complexes with metallothionein isoforms in gibel carp (Carassius auratus gibelio) exposed to environmental metal pollution.

    PubMed

    Infante, Heidi Goenaga; Van Campenhout, Karen; Blust, Ronny; Adams, Freddy C

    2006-07-21

    The capability of post-column isotope dilution (ID) combined with anion-exchange HPLC-ICP-time-of-flight (TOF)-MS was for the first time investigated for environmental quality assessment through metal speciation analysis of metallothionein (MT) isoforms in cytosols of gibel carp (Carassius auratus gibelio), used as biomarkers for environmental metal exposure. A full spectral scanning of the biological sample (with 50 microl injection volume) using ICP-TOF-MS in transient mode allowed fast multi-isotope screening of cytosolic metal-containing fractions and to investigate the presence of matrix-induced interferences. The MT cytosolic fraction of liver and kidney of the carp, sampled at three different sampling sites in Belgium, was partially purified using size-exclusion (SE) HPLC. Quantification of the elements Cd (toxic) and Zn and Cu (essential) associated with MT isoforms in this fraction was addressed using an hybrid approach based on post-column addition of the enriched isotopes 65Cu, 67Zn, 106Cd and monitoring on-line the isotope ratios 63Cu/65Cu, 64Zn/67Zn and 114Cd/106Cd by ICP-MS with a time of flight instrument, which was coupled to anion-exchange HPLC. With this separation method, baseline separation of up to five MT isoforms, which is required for quantitative metal speciation by HPLC-ICP-IDMS, was achieved within a run of 15 min. The MT fraction of the cytosols was also analysed for the total metal content using IDMS with size-exclusion HPLC-ICP-MS and species-unspecific calibration. Results showed significant differences between speciation results and total MT concentrations of control fish and fish from the most contaminated sampling sites, revealing the potential of gibel carp MT for sequestering excess intracellular free-ions (essential and toxic elements) and for its protection against metal toxicity. Preferences for metal sequestration of metal complexes with MT isoforms were also found to be tissue-specific: excess of Cd was found preferably

  6. NMR/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

    PubMed

    Bingol, Kerem; Brüschweiler, Rafael

    2015-06-01

    A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases. PMID:25881480

  7. A downscaled multi-residue strategy for detection of anabolic steroids in bovine urine using gas chromatography tandem mass spectrometry (GC-MS3).

    PubMed

    Impens, S; Van Loco, J; Degroodt, J M; De Brabander, H

    2007-03-14

    Within the scope of the European Community member states' residue monitoring plan, illicit administration of anabolic steroids is monitored at slaughterhouse level as well as on living animals. At farm level, urine is one of the target matrices to detect possible abuse of anabolic steroid growth promoters. Optimisation of the routinely applied analysis method resulted in a procedure for which high performance liquid chromatographic (HPLC) fractionation prior to GC-MS(n) analysis was no longer required. Analytical results could be obtained within 1 day and only 5 mL urine was needed to carry out the screening procedure. Using the downscaled methodology, all validation criteria described in the European Commission document 2002/657/EC could be fulfilled, and the minimum required performance limits (MRPLs) established for anabolic steroids in urine, could be achieved. A higher GC-MS technique's specificity was achieved by detecting the steroids using GC-MS3. Nevertheless, it was decided to screen routinely sampled urine with GC-MS2 whereas GC-MS3 was applied to confirm the presence of anabolic steroid residues in suspected sample extracts. PMID:17386695

  8. Rapid Discrimination of Haemophilus influenzae, H. parainfluenzae, and H. haemolyticus by Fluorescence In Situ Hybridization (FISH) and Two Matrix-Assisted Laser-Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) Platforms

    PubMed Central

    Frickmann, Hagen; Christner, Martin; Donat, Martina; Berger, Anja; Essig, Andreas; Podbielski, Andreas; Hagen, Ralf Matthias; Poppert, Sven

    2013-01-01

    Background Due to considerable differences in pathogenicity, Haemophilus influenzae, H. parainfluenzae and H. haemolyticus have to be reliably discriminated in routine diagnostics. Retrospective analyses suggest frequent misidentifications of commensal H. haemolyticus as H. influenzae. In a multi-center approach, we assessed the suitability of fluorescence in situ hybridization (FISH) and matrix-assisted laser-desorption-ionization time-of-flight mass-spectrometry (MALDI-TOF-MS) for the identification of H. influenzae, H. parainfluenzae and H. haemolyticus to species level. Methodology A strain collection of 84 Haemophilus spp. comprising 50 H. influenzae, 25 H. parainfluenzae, 7 H. haemolyticus, and 2 H. parahaemolyticus including 77 clinical isolates was analyzed by FISH with newly designed DNA probes, and two different MALDI-TOF-MS systems (Bruker, Shimadzu) with and without prior formic acid extraction. Principal Findings Among the 84 Haemophilus strains analyzed, FISH led to 71 correct results (85%), 13 uninterpretable results (15%), and no misidentifications. Shimadzu MALDI-TOF-MS resulted in 59 correct identifications (70%), 19 uninterpretable results (23%), and 6 misidentifications (7%), using colony material applied directly. Bruker MALDI-TOF-MS with prior formic acid extraction led to 74 correct results (88%), 4 uninterpretable results (5%) and 6 misidentifications (7%). The Bruker MALDI-TOF-MS misidentifications could be resolved by the addition of a suitable H. haemolyticus reference spectrum to the system's database. In conclusion, no analyzed diagnostic procedure was free of errors. Diagnostic results have to be interpreted carefully and alternative tests should be applied in case of ambiguous test results on isolates from seriously ill patients. PMID:23646201

  9. Species-Level Identification of Actinomyces Isolates Causing Invasive Infections: Multiyear Comparison of Vitek MS (Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry) to Partial Sequencing of the 16S rRNA Gene.

    PubMed

    Lynch, T; Gregson, D; Church, D L

    2016-03-01

    Actinomyces species are uncommon but important causes of invasive infections. The ability of our regional clinical microbiology laboratory to report species-level identification of Actinomyces relied on molecular identification by partial sequencing of the 16S ribosomal gene prior to the implementation of the Vitek MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS]) system. We compared the use of the Vitek MS to that of 16S rRNA gene sequencing for reliable species-level identification of invasive infections caused by Actinomyces spp. because limited data had been published for this important genera. A total of 115 cases of Actinomyces spp., either alone or as part of a polymicrobial infection, were diagnosed between 2011 and 2014. Actinomyces spp. were considered the principal pathogen in bloodstream infections (n = 17, 15%), in skin and soft tissue abscesses (n = 25, 22%), and in pulmonary (n = 26, 23%), bone (n = 27, 23%), intraabdominal (n = 16, 14%), and central nervous system (n = 4, 3%) infections. Compared to sequencing and identification from the SmartGene Integrated Database Network System (IDNS), Vitek MS identified 47/115 (41%) isolates to the correct species and 10 (9%) isolates to the correct genus. However, the Vitek MS was unable to provide identification for 43 (37%) isolates while 15 (13%) had discordant results. Phylogenetic analyses of the 16S rRNA sequences demonstrate high diversity in recovered Actinomyces spp. and provide additional information to compare/confirm discordant identifications between MALDI-TOF and 16S rRNA gene sequences. This study highlights the diversity of clinically relevant Actinomyces spp. and provides an important typing comparison. Based on our analysis, 16S rRNA gene sequencing should be used to rapidly identify Actinomyces spp. until MALDI-TOF databases are optimized.

  10. Mass spectrometry. [review of techniques

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

    1976-01-01

    Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

  11. Direct identification of microorganisms from positive blood cultures using the lysis-filtration technique and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): a multicentre study.

    PubMed

    Farina, Claudio; Arena, Fabio; Casprini, Patrizia; Cichero, Paola; Clementi, Massimo; Cosentino, Marina; Degl'Innocenti, Roberto; Giani, Tommaso; Luzzaro, Francesco; Mattei, Romano; Mauri, Carola; Nardone, Maria; Rossolini, Gian Maria; Serna Ortega, Paula Andrea; Vailati, Francesca

    2015-04-01

    Microbial identification from blood cultures is essential to institute optimal antibiotic therapy and improve survival possibilities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied to identify bacteria and yeasts from positive blood cultures broths. The aim of this multicentre study was to evaluate the reliability of the lysis-filtration technique associated with MALDI-TOF MS to directly identify microorganisms from 765 positive blood cultures collected in six Italian hospitals. Overall, 675/765 (78.1%) blood isolates were correctly identified at the species level, with significant differences between Gram-negative and Gram-positive bacteria (92.6%, and 69.8%, respectively). Some difficulties arise in identifying Streptococcus pneumoniae, Staphylococcus aureus, yeasts and anaerobes. The lysis-filtration protocol is a suitable procedure in terms of performance in identifying microorganisms, but it is quite expensive and technically time-consuming since the time of filtration is not regular for all the samples. The application of the MALDI-TOF MS technique to the direct microbial identification from positive blood cultures is a very promising approach, even if more experience must be gained to minimize errors and costs. PMID:25938749

  12. Real-time analysis of aromatics in combustion engine exhaust by resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS): a robust tool for chassis dynamometer testing.

    PubMed

    Adam, T W; Clairotte, M; Streibel, T; Elsasser, M; Pommeres, A; Manfredi, U; Carriero, M; Martini, G; Sklorz, M; Krasenbrink, A; Astorga, C; Zimmermann, R

    2012-07-01

    Resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS) is a robust method for real-time analysis of monocyclic and polycyclic aromatic hydrocarbons in complex emissions. A mobile system has been developed which enables direct analysis on site. In this paper, we utilize a multicomponent calibration scheme based on the analytes' photo-ionisation cross-sections relative to a calibrated species. This allows semi-quantification of a great number of components by only calibrating one compound of choice, here toluene. The cross-sections were determined by injecting nebulised solutions of aromatic compounds into the TOF-MS ion source with the help of a HPLC pump. Then, REMPI-TOF-MS was implemented at various chassis dynamometers and test cells and the exhaust of the following vehicles and engines investigated: a compression ignition light-duty (LD) passenger car, a compression ignition LD van, two spark ignition LD passenger cars, 2 two-stroke mopeds, and a two-stroke engine of a string gas trimmer. The quantitative time profiles of benzene are shown. The results indicate that two-stroke engines are a significant source for toxic and cancerogenic compounds. Air pollution and health effects caused by gardening equipment might still be underestimated.

  13. Direct identification of microorganisms from positive blood cultures using the lysis-filtration technique and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): a multicentre study.

    PubMed

    Farina, Claudio; Arena, Fabio; Casprini, Patrizia; Cichero, Paola; Clementi, Massimo; Cosentino, Marina; Degl'Innocenti, Roberto; Giani, Tommaso; Luzzaro, Francesco; Mattei, Romano; Mauri, Carola; Nardone, Maria; Rossolini, Gian Maria; Serna Ortega, Paula Andrea; Vailati, Francesca

    2015-04-01

    Microbial identification from blood cultures is essential to institute optimal antibiotic therapy and improve survival possibilities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied to identify bacteria and yeasts from positive blood cultures broths. The aim of this multicentre study was to evaluate the reliability of the lysis-filtration technique associated with MALDI-TOF MS to directly identify microorganisms from 765 positive blood cultures collected in six Italian hospitals. Overall, 675/765 (78.1%) blood isolates were correctly identified at the species level, with significant differences between Gram-negative and Gram-positive bacteria (92.6%, and 69.8%, respectively). Some difficulties arise in identifying Streptococcus pneumoniae, Staphylococcus aureus, yeasts and anaerobes. The lysis-filtration protocol is a suitable procedure in terms of performance in identifying microorganisms, but it is quite expensive and technically time-consuming since the time of filtration is not regular for all the samples. The application of the MALDI-TOF MS technique to the direct microbial identification from positive blood cultures is a very promising approach, even if more experience must be gained to minimize errors and costs.

  14. Differentiating the Bishop ash bed and related tephra layers by elemental-based similarity coefficients of volcanic glass shards using solution inductively coupled plasma-mass spectrometry (S-ICP-MS)

    USGS Publications Warehouse

    Knott, J.R.; Sarna-Wojcicki, A. M.; Montanez, I.P.; Wan, E.

    2007-01-01

    Volcanic glass samples from the same volcanic center (intra-source) often have a similar major-element composition. Thus, it can be difficult to distinguish between individual tephra layers, particularly when using similarity coefficients calculated from electron microprobe major-element measurements. Minor/trace element concentrations in glass can be determined by solution inductively coupled plasma mass spectrometry (S-ICP-MS), but have not been shown as suitable for use in large tephrochronologic databases. Here, we present minor/trace-element concentrations measured by S-ICP-MS and compare these data by similarity coefficients, the method commonly used in large databases. Trial samples from the Bishop Tuff, the upper and lower tuffs of Glass Mountain and the tuffs of Mesquite Spring suites from eastern California, USA, which have an indistinguishable major-element composition, were analyzed using S-ICP-MS. The resulting minor/trace element similarity coefficients clearly separated the suites of tephra layers and, in most cases, individual tephra layers within each suite. Comparisons with previous instrumental neutron activation analysis (INAA) elemental measurements were marginally successful. This is important step toward quantitative correlation in large tephrochronologic databases to achieve definitive identification of volcanic glass samples and for high-resolution age determinations. ?? 2007 Elsevier Ltd and INQUA.

  15. Application of 13C isotope labeling using liquid chromatography mass spectrometry (LC-MS) to determining phosphate-containing metabolic incorporation

    PubMed Central

    Bhowmik, Salil Kumar; Putluri, Vasanta; Kommagani, Ramakrishna; Konde, Sai Aparna; Lydon, John P.; Sreekumar, Arun; Putluri, Nagireddy

    2016-01-01

    Here, we describe an approach wherein negative electrospray ionization mass spectrometry has used to understand the relative flux through phosphate containing metabolic intermediates associated with central carbon metabolism after administering cells with 13C-labeled substrates. The method was applied to examine the 13C incorporation through glycolysis in T47D breast cancer cells and showed reduction of glycolytic relative flux upon treatment with 2-Deoxyglucose. PMID:24338880

  16. Characterization of ACE Inhibitory Peptides from Mactra veneriformis Hydrolysate by Nano-Liquid Chromatography Electrospray Ionization Mass Spectrometry (Nano-LC-ESI-MS) and Molecular Docking

    PubMed Central

    Liu, Rui; Zhu, Yunhan; Chen, Jiao; Wu, Hao; Shi, Lei; Wang, Xinzhi; Wang, Lingchong

    2014-01-01

    Food-derived bioactive compounds are gaining increasing significance in life sciences. In the present study, we identified angiotensin I-converting enzyme (ACE)-inhibitory peptides from Mactra veneriformis hydrolysate using a nano-LC-MS/MS method. Mactra veneriformis hydrolysate was first separated into four fractions (F1–F4) based on molecular weight by ultrafiltration. The fraction with molecular weight lower than 1 kDa (F1) showed the highest ACE inhibitory activity. F1 was then analyzed by a high throughput nano-LC-MS/MS method and sequences of peptides in F1 were calculated accordingly. The 27 peptides identified as above were chemically synthesized and tested for ACE-inhibitory activity. The hexapeptide VVCVPW showed the highest potency with an IC50 value of 4.07 μM. We then investigated the interaction mechanism between the six most potent peptides and ACE by molecular docking. Our docking results suggested that the ACE inhibitory peptides bind to ACE via interactions with His383, His387, and Glu411 residues. Particularly, similar to the thiol group of captopril, the cysteine thiol group of the most potent peptide VVCVPW may play a key role in the binding of this peptide to the ACE active site. PMID:24983637

  17. Biodegradation of carbamazepine and clarithromycin by Trichoderma harzianum and Pleurotus ostreatus investigated by liquid chromatography - high-resolution tandem mass spectrometry (FTICR MS-IRMPD).

    PubMed

    Buchicchio, Alessandro; Bianco, Giuliana; Sofo, Adriano; Masi, Salvatore; Caniani, Donatella

    2016-07-01

    In this study, the capability of pharmaceutical biodegradation of fungus Trichoderma harzianum was evaluated through the comparison with the well-known biodegradation capability of white-rot fungus Pleurotus ostreatus. The study was performed in aqueous phase under aerobic conditions, using two of the most frequently detected drugs in water bodies: carbamazepine and clarithromycin, with concentrations commonly found in treated wastewater (4μg/l and 0.03μg/l respectively). For the first time, we demonstrated that T. harzianum is able to remove carbamazepine and clarithromycin. The analyses were performed by reversed-phase liquid chromatography/mass spectrometry, using high-resolution Fourier-transform ion cyclotron resonance mass spectrometry upon electrospray ionization in positive ion mode. The high selectivity and mass accuracy provided by high-resolution mass spectrometry, allowed us to identify some unknown metabolites. On the basis of our study, the major metabolites detected in liquid culture treated by T. harzianum were: 14-hydroxy-descladinosyl- and descladinosyl-clarithromycin, which are pharmacologically inactive products not dangerous for the environment. PMID:27039063

  18. The potential of combining ion trap/MS/MS and TOF/MS for identification of emerging contaminants

    USGS Publications Warehouse

    Ferrer, I.; Furlong, E.T.; Heine, C.E.; Thurman, E.M.

    2002-01-01

    The use of a method combining ion trap tandem mass spectrometry (MS/MS) and time of flight mass spectrometry (TOF/MS) for identification of emerging contaminates was discussed. The two tools together complemented each other in sensitivity, fragmentation and accurate mass determination. Liquid chromatography/electrospray ionization/ion-trap tandem mass spectrometry (LC/ESI/MS/MS), in positive ion mode of operation, was used to separate and identify specific compounds. Diagnostic fragment ions were obtained for a polyethyleneglycol(PEG) homolog by ion trap MS/MS, and fragments were measured by TOF/MS. It was observed that the combined method gave an exact mass measurement that differed from the calculated mass.

  19. Identification of the Metabolic Enzyme Involved Morusin Metabolism and Characterization of Its Metabolites by Ultraperformance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UPLC/Q-TOF-MS/MS)

    PubMed Central

    Shi, Xianbao; Mackie, Brianna; Zhang, Gang; Song, Yonggui; Su, Dan; Liu, Yali

    2016-01-01

    Morusin, the important active component of a traditional Chinese medicine, Morus alba L., has been shown to exhibit many vital pharmacological activities. In this study, six recombinant CYP450 supersomes and liver microsomes were used to perform metabolic studies. Chemical inhibition studies and screening assays with recombinant human cytochrome P450s were also used to characterize the CYP450 isoforms involved in morusin metabolism. The morusin metabolites identified varied greatly among different species. Eight metabolites of morusin were detected in the liver microsomes from pigs (PLMs), rats (RLMs), and monkeys (MLMs) by LC-MS/MS and six metabolites were detected in the liver microsomes from humans (HLMs), rabbits (RAMs), and dogs (DLMs). Four metabolites (M1, M2, M5, and M7) were found in all species and hydroxylation was the major metabolic transformation. CYP1A2, CYP2C9, CYP2D6, CYP2E1, CYP3A4, and CYP2C19 contributed differently to the metabolism of morusin. Compared to other CYP450 isoforms, CYP3A4 played the most significant role in the metabolism of morusin in human liver microsomes. These results are significant to better understand the metabolic behaviors of morusin among various species.

  20. Fast Detection of Phenolic Compounds in Extracts of Easter Pears (Pyrus communis) from the Atacama Desert by Ultrahigh-Performance Liquid Chromatography and Mass Spectrometry (UHPLC-Q/Orbitrap/MS/MS).

    PubMed

    Simirgiotis, Mario J; Quispe, Cristina; Bórquez, Jorge; Areche, Carlos; Sepúlveda, Beatriz

    2016-01-15

    A small Chilean variety of pears growing in the town of Toconao, an oasis located at the northeastern edge of the Salar de Atacama, northern Chile, was studied by means of modern PDA and high resolution mass spectral data (UHPLC-PDA-HESI-orbitrap-MS/MS). In addition, the antioxidant features of the fruits were compared with the varieties Packhman's Triumph and Abate Fetel and correlated with the presence of phenolic compounds. The non-pigmented phenolics were fingerprinted and related to the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics and flavonoids measured by spectroscopic methods. The machine allowed a fast separation of 15 min employing a flow rate of 1 mL per minute and could accurately identify 25 compounds, including several isorhamnetin derivatives and phenolic acids, present in the peel and pulps of this Chilean variety for the first time. The compounds were monitored using a wavelength range of 210-800 nm. The native small Chilean pear showed the highest antioxidant activity measured as the bleaching of the DPPH radical, the ferric reducing antioxidant power and superoxide anion scavenging activity (8.61 ± 0.65 μg/mL, 712.63 ± 12.12 micromols trolox equivalents (μmol/TE)/100 g FW, and 82.89% ± 2.52% at 100 μg/mL, respectively).

  1. Fast Detection of Phenolic Compounds in Extracts of Easter Pears (Pyrus communis) from the Atacama Desert by Ultrahigh-Performance Liquid Chromatography and Mass Spectrometry (UHPLC-Q/Orbitrap/MS/MS).

    PubMed

    Simirgiotis, Mario J; Quispe, Cristina; Bórquez, Jorge; Areche, Carlos; Sepúlveda, Beatriz

    2016-01-01

    A small Chilean variety of pears growing in the town of Toconao, an oasis located at the northeastern edge of the Salar de Atacama, northern Chile, was studied by means of modern PDA and high resolution mass spectral data (UHPLC-PDA-HESI-orbitrap-MS/MS). In addition, the antioxidant features of the fruits were compared with the varieties Packhman's Triumph and Abate Fetel and correlated with the presence of phenolic compounds. The non-pigmented phenolics were fingerprinted and related to the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics and flavonoids measured by spectroscopic methods. The machine allowed a fast separation of 15 min employing a flow rate of 1 mL per minute and could accurately identify 25 compounds, including several isorhamnetin derivatives and phenolic acids, present in the peel and pulps of this Chilean variety for the first time. The compounds were monitored using a wavelength range of 210-800 nm. The native small Chilean pear showed the highest antioxidant activity measured as the bleaching of the DPPH radical, the ferric reducing antioxidant power and superoxide anion scavenging activity (8.61 ± 0.65 μg/mL, 712.63 ± 12.12 micromols trolox equivalents (μmol/TE)/100 g FW, and 82.89% ± 2.52% at 100 μg/mL, respectively). PMID:26784158

  2. Identification of the Metabolic Enzyme Involved Morusin Metabolism and Characterization of Its Metabolites by Ultraperformance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UPLC/Q-TOF-MS/MS)

    PubMed Central

    Shi, Xianbao; Mackie, Brianna; Zhang, Gang; Song, Yonggui; Su, Dan; Liu, Yali

    2016-01-01

    Morusin, the important active component of a traditional Chinese medicine, Morus alba L., has been shown to exhibit many vital pharmacological activities. In this study, six recombinant CYP450 supersomes and liver microsomes were used to perform metabolic studies. Chemical inhibition studies and screening assays with recombinant human cytochrome P450s were also used to characterize the CYP450 isoforms involved in morusin metabolism. The morusin metabolites identified varied greatly among different species. Eight metabolites of morusin were detected in the liver microsomes from pigs (PLMs), rats (RLMs), and monkeys (MLMs) by LC-MS/MS and six metabolites were detected in the liver microsomes from humans (HLMs), rabbits (RAMs), and dogs (DLMs). Four metabolites (M1, M2, M5, and M7) were found in all species and hydroxylation was the major metabolic transformation. CYP1A2, CYP2C9, CYP2D6, CYP2E1, CYP3A4, and CYP2C19 contributed differently to the metabolism of morusin. Compared to other CYP450 isoforms, CYP3A4 played the most significant role in the metabolism of morusin in human liver microsomes. These results are significant to better understand the metabolic behaviors of morusin among various species. PMID:27698677

  3. The collaboratory for MS3D: a new cyberinfrastructure for the structural elucidation of biological macromolecules and their assemblies using mass spectrometry-based approaches.

    PubMed

    Yu, Eizadora T; Hawkins, Arie; Kuntz, Irwin D; Rahn, Larry A; Rothfuss, Andrew; Sale, Kenneth; Young, Malin M; Yang, Christine L; Pancerella, Carmen M; Fabris, Daniele

    2008-11-01

    Modern biomedical research is evolving with the rapid growth of diverse data types, biophysical characterization methods, computational tools and extensive collaboration among researchers spanning various communities and having complementary backgrounds and expertise. Collaborating researchers are increasingly dependent on shared data and tools made available by other investigators with common interests, thus forming communities that transcend the traditional boundaries of the single research laboratory or institution. Barriers, however, remain to the formation of these virtual communities, usually due to the steep learning curve associated with becoming familiar with new tools, or with the difficulties associated with transferring data between tools. Recognizing the need for shared reference data and analysis tools, we are developing an integrated knowledge environment that supports productive interactions among researchers. Here we report on our current collaborative environment, which focuses on bringing together structural biologists working in the area of mass spectrometric based methods for the analysis of tertiary and quaternary macromolecular structures (MS3D) called the Collaboratory for MS3D (C-MS3D). C-MS3D is a Web-portal designed to provide collaborators with a shared work environment that integrates data storage and management with data analysis tools. Files are stored and archived along with pertinent meta data in such a way as to allow file handling to be tracked (data provenance) and data files to be searched using keywords and modification dates. While at this time the portal is designed around a specific application, the shared work environment is a general approach to building collaborative work groups. The goal of this is to not only provide a common data sharing and archiving system, but also to assist in the building of new collaborations and to spur the development of new tools and technologies. PMID:18817429

  4. Quantitative protein topography analysis and high-resolution structure prediction using hydroxyl radical labeling and tandem-ion mass spectrometry (MS).

    PubMed

    Kaur, Parminder; Kiselar, Janna; Yang, Sichun; Chance, Mark R

    2015-04-01

    Hydroxyl radical footprinting based MS for protein structure assessment has the goal of understanding ligand induced conformational changes and macromolecular interactions, for example, protein tertiary and quaternary structure, but the structural resolution provided by typical peptide-level quantification is limiting. In this work, we present experimental strategies using tandem-MS fragmentation to increase the spatial resolution of the technique to the single residue level to provide a high precision tool for molecular biophysics research. Overall, in this study we demonstrated an eightfold increase in structural resolution compared with peptide level assessments. In addition, to provide a quantitative analysis of residue based solvent accessibility and protein topography as a basis for high-resolution structure prediction; we illustrate strategies of data transformation using the relative reactivity of side chains as a normalization strategy and predict side-chain surface area from the footprinting data. We tested the methods by examination of Ca(+2)-calmodulin showing highly significant correlations between surface area and side-chain contact predictions for individual side chains and the crystal structure. Tandem ion based hydroxyl radical footprinting-MS provides quantitative high-resolution protein topology information in solution that can fill existing gaps in structure determination for large proteins and macromolecular complexes.

  5. Selenium transformation studies during broccoli (Brassica oleracea) growing process by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS).

    PubMed

    Pedrero, Zoyne; Elvira, Daniel; Cámara, Carmen; Madrid, Yolanda

    2007-07-23

    Selenium uptake and transformation was studied in Se-enriched Broccoli (Brassica olearacea). Plants were grown in hydroponic culture and exposed during 40 days to Na2SeO3 (1 mg L(-1)). After growing, the plants were harvested and their different parts (roots, stems and fruit) were analyzed by ICP-MS or LC-ICP-MS. Se-species were identified and quantified after enzymatic extraction by using both an anion exchange (PRP-X100), and a size exclusion/ion exchange (Shodex Asahipak) chromatographic columns. Selenium translocation and transformation Se species in plants was studied through the Se-speciation in root, stem and fruit. After 40 days of exposure, selenomethionine was the major species found in roots, however, Se-methylselenocysteine was the main species found in the fruit, suggesting Broccoli as a source of this important selenoamino acid in human diet. However, the degree of meal processing influences the stability of Se-aminoacids. Speciation studies in boiled Broccoli and in the extraction water were also carried out. This experiment revealed a noticeable degradation of Se-methylselenocysteine in the boiled Broccoli fruit. Proteins soluble in Tris-HCl were analyzed by two-dimensional chromatography coupled to ICP-MS. The results obtained contribute not only to a deeper understanding of Se accumulation mechanisms by plants but also to further functional food complements preparation and the effect of food processing on species stability.

  6. Quantitative Protein Topography Analysis and High-Resolution Structure Prediction Using Hydroxyl Radical Labeling and Tandem-Ion Mass Spectrometry (MS)*

    PubMed Central

    Kaur, Parminder; Kiselar, Janna; Yang, Sichun; Chance, Mark R.

    2015-01-01

    Hydroxyl radical footprinting based MS for protein structure assessment has the goal of understanding ligand induced conformational changes and macromolecular interactions, for example, protein tertiary and quaternary structure, but the structural resolution provided by typical peptide-level quantification is limiting. In this work, we present experimental strategies using tandem-MS fragmentation to increase the spatial resolution of the technique to the single residue level to provide a high precision tool for molecular biophysics research. Overall, in this study we demonstrated an eightfold increase in structural resolution compared with peptide level assessments. In addition, to provide a quantitative analysis of residue based solvent accessibility and protein topography as a basis for high-resolution structure prediction; we illustrate strategies of data transformation using the relative reactivity of side chains as a normalization strategy and predict side-chain surface area from the footprinting data. We tested the methods by examination of Ca+2-calmodulin showing highly significant correlations between surface area and side-chain contact predictions for individual side chains and the crystal structure. Tandem ion based hydroxyl radical footprinting-MS provides quantitative high-resolution protein topology information in solution that can fill existing gaps in structure determination for large proteins and macromolecular complexes. PMID:25687570

  7. MS-DIAL: Data Independent MS/MS Deconvolution for Comprehensive Metabolome Analysis

    PubMed Central

    Tsugawa, Hiroshi; Cajka, Tomas; Kind, Tobias; Ma, Yan; Higgins, Brendan; Ikeda, Kazutaka; Kanazawa, Mitsuhiro; VanderGheynst, Jean; Fiehn, Oliver; Arita, Masanori

    2015-01-01

    Data-independent acquisition (DIA) in liquid chromatography tandem mass spectrometry (LC-MS/MS) provides more comprehensive untargeted acquisition of molecular data. Here we provide an open-source software pipeline, MS-DIAL, to demonstrate how DIA improves simultaneous identification and quantification of small molecules by mass spectral deconvolution. For reversed phase LC-MS/MS, our program with an enriched LipidBlast library identified total 1,023 lipid compounds from nine algal strains to highlight their chemotaxonomic relationships. PMID:25938372

  8. Determination of (90)Sr in soil samples using inductively coupled plasma mass spectrometry equipped with dynamic reaction cell (ICP-DRC-MS).

    PubMed

    Feuerstein, J; Boulyga, S F; Galler, P; Stingeder, G; Prohaska, T

    2008-11-01

    A rapid method is reported for the determination of (90)Sr in contaminated soil samples in the vicinity of the Chernobyl Nuclear Power Plant by ICP-DRC-MS. Sample preparation and measurement procedures focus on overcoming the isobaric interference of (90)Zr, which is present in soils at concentrations higher by more than six orders of magnitude than (90)Sr. Zirconium was separated from strontium in two steps to reduce the interference by (90)Zr(+) ions by a factor of more than 10(7): (i) by ion exchange using a Sr-specific resin and (ii) by reaction with oxygen as reaction gas in a dynamic reaction cell (DRC) of a quadrupole ICP-MS. The relative abundance sensitivity of the ICP-MS was studied systematically and the peak tailing originating from (88)Sr on mass 90 u was found to be about 3 x 10(-9). Detection limits of 4 fg g(-1) (0.02 Bq g(-1)) were achieved when measuring Sr solutions containing no Zr. In digested uncontaminated soil samples after matrix separation as well as in a solution of 5 microg g(-1) Sr and 50 ng g(-1) Zr a detection limit of 0.2 pg g(-1) soil (1 Bq g(-1) soil) was determined. (90)Sr concentrations in three soil samples collected in the vicinity of the Chernobyl Nuclear Power Plant were 4.66+/-0.27, 13.48+/-0.68 and 12.9+/-1.5 pg g(-1) corresponding to specific activities of 23.7+/-1.3, 68.6+/-3.5 and 65.6+/-7.8 Bq g(-1), respectively. The ICP-DRC-MS results were compared to the activities measured earlier by radiometry. Although the ICP-DRC-MS is inferior to commonly used radiometric methods with respect to the achievable minimum detectable activity it represents a time- and cost-effective alternative technique for fast monitoring of high-level (90)Sr contamination in environmental or nuclear industrial samples down to activities of about 1 Bq g(-1). PMID:18760512

  9. Quantitative low-volume assay for simultaneous determination of fentanyl, norfentanyl, and minor metabolites in human plasma and urine by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Mahlke, Nina Sophia; Ziesenitz, Victoria; Mikus, Gerd; Skopp, Gisela

    2014-09-01

    A rapid and sensitive liquid chromatography/tandem mass spectrometric (LC-MS/MS) method for simultaneous quantification of fentanyl (F), norfentanyl (NF), despropionylfentanyl (DPF), and hydroxynorfentanyl (OHNF) in human plasma and urine specimens has been developed and validated according to international guidelines. Analytes were extracted from 250-μL plasma or urine by liquid-liquid extraction. OHNF in urine affords a second extraction step and analysis with a different column. Calibration curves in plasma were linear from 0.05-10 ng/mL for F, 0.07-0.5 ng/mL for NF, 0.02-1.0 ng/ml for DPF, and 0.67-3.0 ng/mL for OHNF; in urine, from 0.09-10.0, 0.17-50, 0.08-1.0, and 1.0-5.0 ng/mL for F, NF, DPF, and OHNF, respectively. Analytical bias and intra- and inter-assay imprecision were within ± 15 % of target, except for OHNF in plasma and DPF in urine at the respective lower quality control level. All analytes were stable in processed samples when stored for 24 h at room temperature. Recoveries and process efficiencies were above 82.9 and 75.1 % for all analytes in plasma and urine. The low level of DPF in plasma indicated with a matrix effect of 71.3 % moderate ion suppression, all other analytes in plasma and urine showed no matrix effects. The lower limit of quantification (LOQ) in plasma was 0.05, 0.07, 0.02 and 0.67 ng/mL for F, NF, DPF, and OHNF, respectively. In urine, the LOQ of F, NF, DPF, and OHNF were 0.09, 0.17, 0.08, and 1.28 ng/mL, respectively. This assay has been applied to human specimens collected during a clinical drug-drug interaction study.

  10. Analysis of llicit and illicit drugs in waste, surface and lake water samples using large volume direct injection high performance liquid chromatography--electrospray tandem mass spectrometry (HPLC-MS/MS).

    PubMed

    Berset, Jean-Daniel; Brenneisen, Rudolf; Mathieu, Christoph

    2010-11-01

    Llicit and illicit drugs represent a recent group of emerging contaminants and have been found in the aquatic environment. A HPLC-MS/MS method was developed using direct injection (DI) of larger volumes and a polar endcapped reversed-phase (RP) column to measure drug components in water samples belonging to the cocaine group, opiates, amphetamine-like stimulants and metabolites thereof. After validation, including sensitivity, linearity, recovery, precision and matrix effect studies, most drugs could be detected with limits of quantitation (LOQ) of 20 ng L(-1) in wastewater (WW) and 0.2 ng L(-1) in surface water. The major substances found in influents and effluents were cocaine (COC), benzoylecgonine (BE), morphine (MO), methadone (MD) and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) with concentrations up to 2 μg L(-1), followed by codeine (COD) and the amphetamines which ranged between 20 and 400 ng L(-1). Except for MO, COD and EDDP levels were generally lower in the effluents. River and lake water contained trace amounts of mainly BE, MD and EDDP from the high pg L(-1) to the low ng L(-1) level. Monitoring COC and BE levels over 11 consecutive days in influents and effluents suggests a consumption preference on week-end days. Finally, measuring an influent after a major music event revealed that sewage treatment plants (STPs) are exposed, for a limited period of time, to high concentration peaks of COC and BE as well as amphetamine-like stimulants such as ecstasy (MDMA).

  11. Simultaneous determination of Se, trace elements and major elements in Se-rich rice by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) after microwave digestion.

    PubMed

    Wei, Yi Hua; Zhang, Jin Yan; Zhang, Da Wen; Luo, Lin Guang; Tu, Tian Hua

    2014-09-15

    A quick and accurate method was devised to determine Se, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr and Zn in Se-rich rice samples by microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS). Spectral interferences on Se were eliminated using methane as a reaction gas in the dynamic reaction cell (DRC). Rhodium was used as an internal standard to compensate for sample matrix effects. A rice-certified reference material (CRM) (GBW 10010) was used to verify the accuracy of the method. The method detection limits were 0.001-0.03 mg/kg, analyte recoveries were 85-108% and precisions (RSDs) ranged from 2.1% to 5.8%. Correlation analysis showed that the Se concentrations in the Se-rich rice samples correlated well with the Cu concentrations (r=0.53, p<0.05).

  12. Elemental profiling and geographical differentiation of Ethiopian coffee samples through inductively coupled plasma-optical emission spectroscopy (ICP-OES), ICP-mass spectrometry (ICP-MS) and direct mercury analyzer (DMA).

    PubMed

    Habte, Girum; Hwang, In Min; Kim, Jae Sung; Hong, Joon Ho; Hong, Young Sin; Choi, Ji Yeon; Nho, Eun Yeong; Jamila, Nargis; Khan, Naeem; Kim, Kyong Su

    2016-12-01

    This study was aimed to establish the elemental profiling and provenance of coffee samples collected from eleven major coffee producing regions of Ethiopia. A total of 129 samples were analyzed for forty-five elements using inductively coupled plasma (ICP)-optical emission spectroscopy (OES), ICP-mass spectrometry (MS) and direct mercury analyzer (DMA). Among the macro elements, K showed the highest levels whereas Fe was found to have the lowest concentration values. In all the samples, Ca, K, Mg, P and S contents were statistically significant (p<0.05). Micro elements showed the concentrations order of: Mn>Cu>Sr>Zn>Rb>Ni>B. Contents of the trace elements were lower than the permissible standard values. Inter-regions differentiation by cluster analysis (CA), linear discriminant analysis (LDA) and principal component analysis (PCA) showed that micro and trace elements are the best chemical descriptors of the analyzed coffee samples. PMID:27374562

  13. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins.

    PubMed

    Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

    2016-01-01

    It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks ("seeds") for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn's largest moon, Titan.

  14. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins.

    PubMed

    Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

    2016-01-01

    It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks ("seeds") for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn's largest moon, Titan. PMID:27023520

  15. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins

    PubMed Central

    Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

    2016-01-01

    It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks (“seeds”) for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn’s largest moon, Titan. PMID:27023520

  16. Separate vaporisation of boric acid and inorganic boron from tungsten sample cuvette-tungsten boat furnace followed by the detection of boron species by inductively coupled plasma mass spectrometry and atomic emission spectrometry (ICP-MS and ICP-AES).

    PubMed

    Kataoka, Hiroko; Okamoto, Yasuaki; Tsukahara, Satoshi; Fujiwara, Terufumi; Ito, Kazuaki

    2008-03-10

    Utilising extremely different vaporisation properties of boron compounds, the determination procedures of volatile boric acid and total boron using tungsten boat furnace (TBF) ICP-MS and TBF-ICP-AES have been investigated. For the determination of volatile boric acid by TBF-ICP-MS, tetramethylammonium hydroxide (TMAH, Me(4)NOH) was used as a chemical modifier to retain it during drying and ashing stages. As for the total boron, not only non-volatile inorganic boron such as boron nitride (BN), boron carbide (B(4)C), etc. but also boric acid (B(OH)(3)) was decomposed by a furnace-fusion digestion with NaOH to produce sodium salt of boron, a suitable species for the electrothermal vaporisation (ETV) procedure. The proposed method was applied to the analysis of various standard reference materials. The analytical results for various biological and steel samples are described.

  17. 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.

  18. Simultaneous quantification of simvastatin and simvastatin hydroxy acid in blood serum at physiological pH by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS).

    PubMed

    Bews, Hilary J; Carlson, Jules C; Jha, Aruni; Basu, Sujata; Halayko, Andrew J; Wong, Charles S

    2014-02-01

    Simvastatin attenuates airway inflammation and hyperreactivity, hallmarks of asthma, in allergen-challenged mice. As such, it is under consideration as a novel therapeutic, thus it is important to quantify the levels of simvastatin and its pharmacologically active and interconvertible metabolite, simvastatin hydroxy acid, that can be attained in the body. Methods exist to measure the concentrations of these compounds in biological media; however they do not maintain a physiological pH, and as a result do not accurately measure the ratio of these two compounds that exists in vivo. We developed a new method to measure simvastatin and simvastatin hydroxy acid more accurately in serum from mice by ultra high performance liquid chromatography-tandem mass spectrometry. We minimized the time that the compounds were in aqueous solution, and buffered samples to a physiological pH value of 7.4. Limits of quantification (LOQ) were 0.16 ng mL(-1) extract (1.3 ng mL(-1) serum) for simvastatin, and 8.3 ng mL(-1) extract (66 ng mL(-1) serum) for simvastatin hydroxy acid, respectively. No interconversion was observed, based on spike-and-recovery experiments of solutions containing both compounds. The method was applied using biological samples from mice challenged with house dust mite extract and simultaneously treated with subcutaneous simvastatin injection. Simvastatin hydroxy acid concentrations became significantly increased after a 2 week pre-treatment regime, whereas simvastatin concentrations were below the LOQ for all serum samples.

  19. Applications of direct analysis in real time-mass spectrometry (DART-MS) in Allium chemistry. (Z)-butanethial S-oxide and 1-butenyl thiosulfinates and their S-(E)-1-butenylcysteine S-oxide precursor from Allium siculum.

    PubMed

    Kubec, Roman; Cody, Robert B; Dane, A John; Musah, Rabi A; Schraml, Jan; Vattekkatte, Abith; Block, Eric

    2010-01-27

    Lachrymatory (Z)-butanethial S-oxide along with several 1-butenyl thiosulfinates was detected by DART mass spectrometry upon cutting Allium siculum , a popular ornamental Allium species used in some cultures as a spice. (Z)-Butanethial S-oxide isolated from the plant was shown to be identical to a synthetic sample. Its likely precursor, (R(S),R(C),E)-S-(1-butenyl)cysteine S-oxide (homoisoalliin), was isolated from homogenates of A. siculum, and a closely related species Allium tripedale , and fully characterized. Through use of LC-MS, a series of related gamma-glutamyl derivatives were tentatively identified in A. siculum and A. tripedale homogenates, including gamma-glutamyl-(E)-S-(1-butenyl)cysteine and its S-oxide, gamma-glutamyl-S-butylcysteine and its S-oxide, and gamma-glutamyl-S-methylcysteine and its S-oxide. Because compounds containing the 1-butenyl group have not been previously identified in genus Allium species, this work extends the range of known Allium sulfur compounds. The general applicability of DART mass spectrometry in identifying naturally occurring, thermally fragile thial S-oxides and thiosulfinates is illustrated with onion, Allium cepa , as well as a plant from a different genus, Petiveria alliacea .

  20. Quantitative Determination of Perfluorochemicals and Fluorotelomer Alcohols in Plants from Biosolid-Amended Fields using LC/MS/MS and GC/MS

    EPA Science Inventory

    Analytical methods for determining perfluorochemicals (PFCs) and fluorotelomer alcohols (FTOHs) in plants using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) were developed, and applied to quantify a suite of analytes i...

  1. Hydrogen Exchange Mass Spectrometry.

    PubMed

    Mayne, Leland

    2016-01-01

    Hydrogen exchange (HX) methods can reveal much about the structure, energetics, and dynamics of proteins. The addition of mass spectrometry (MS) to an earlier fragmentation-separation HX analysis now extends HX studies to larger proteins at high structural resolution and can provide information not available before. This chapter discusses experimental aspects of HX labeling, especially with respect to the use of MS and the analysis of MS data.

  2. Fe isotope analysis by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using 58Fe-54Fe double-spike

    NASA Astrophysics Data System (ADS)

    Dideriksen, K.; Baker, J.; Stipp, S. L. S.; Williams, H. M.

    2003-04-01

    The growth of Fe isotope studies has been facilitated by the advent of plasma-source mass spectroscopy. To-date, MC-ICP-MS determination of Fe isotope fractionation has relied on sample-standard bracketing or Cu-doping techniques to correct for instrumental mass bias (e.g. Anbar et al. 2000). Both approaches are robust, but MC-ICP-MS analysis using a 58Fe-54Fe double-spike may have several advantages over these methods: 1) Isobaric interference on mass 54 is reduced dramatically; background contributions on 58, 57, 56 and 54 from Ni, ArOH, ArO and ArN are le2.4 ɛ-unit. 2) Isotopic fractionation, which may occur during chemical separation, can be accounted for by spiking before chemical separation. This may prove valuable when several chemical separation passes are required, for example when analysis of trace amounts of Fe in Fe-poor material is necessary. 3) The method does not require extensive analysis of standards. 4) Potential inaccuracies, caused by sample and standards having slightly different matrices or Fe oxidation states do not affect double spike analysis. On the other hand, the double-spike method also has disadvantages. Careful washout between sample measurements is crucial for correct determination of Fe isotope ratios given the slightly variable Fe isotope ratios produced by different sample to spike ratios. We have developed a method for Fe isotope analysis using a double spike procedure by MC-ICP-MS without a collision cell (VG Axiom) on ˜10 ppm Fe solutions. Preliminary experiments suggest that a long-term external reproducibility of less than 1.1 ɛ-unit (2 SD) can be achieved. Literature: Anbar A.D.; Roe J.E.; Barling J.; Nealson K.H.(2000) Nonbiological fractionation of iron isotopes. In: Science. Vol. 288 (5463). pp 126-128.

  3. Simultaneous detection of multi-allergens in an incurred food matrix using ELISA, multiplex flow cytometry and liquid chromatography mass spectrometry (LC-MS).

    PubMed

    Gomaa, Ahmed; Boye, Joyce

    2015-05-15

    Food allergy is a public health concern and an important food safety issue. Food allergies affect up to 6% of infants and children and 4% of adults. The objective of this work was to determine differences in the detection of single and multiple allergens (i.e., casein, soy protein, and gluten) in an incurred food matrix before and after baking. Cookies were used as a model food system. Three methods, namely, multiplex assay (a new optimized method based on flow cytometry for multiple allergen analysis), enzyme-linked immunosorbent assay (ELISA) using commercial kits and LC-MS were used to detect allergens in the samples before and after baking. The ELISA kits performed well in detecting allergens in the raw samples with recoveries of 91-108%, 88-127% and 85-108% for casein, soy protein and gluten, respectively. Recoveries were poor for the baked cookies (67-90%, 66-95% and 66-88% for casein, soy protein and gluten, respectively). The multiplex flow cytometry assay permitted multiple allergen detection in the raw samples, with the following recoveries based on soluble protein: casein, 95-107%; soy protein, 92-97%, and gluten, 96-99%. Data for the baked cookies were as follows: casein, 84-90%; soy protein, 80-88%, and gluten, 80-90%. The LC-MS technique detected marker peptides that could be used to identify allergens in the baked food samples up to concentrations of 10 ppm for casein and soy protein, and 100 ppm for gluten. To the best of our knowledge, the current study is the first to compare ELISA, LC-MS and multiplex flow cytometry methods for the detection of multiple allergens simultaneously incurred in a model food system.

  4. Validation and Uncertainty of the method for multiresidue analysis of 35 pesticides in melon using Gas Chromatography Coupled to Quadrupole Mass Spectrometry (GC-QP/MS)

    NASA Astrophysics Data System (ADS)

    Milhome, M. A. L.; Sousa, J. S.; Andrade, G. A.; de Castro, R. C.; Lima, L. K.; Lima, C. G.; Nascimento, R. F.

    2015-01-01

    QuEChERS method and detection in GC/SQ-MS were validated for the analysis of 35 pesticides in melon. Validation parameters (selectivity, linearity, LOD, LOQ, accuracy and precision) were determined according ABNT NBR 14029:2005. The recoveries rates for all the pesticides studied were from 63% to 117% with relative standard deviation (RSD) lower than 15% in the concentration range of 0.05 - 0.20 mg/kg. The limit of quantification (LOQ) for most compounds were below the MRLs established in Brazil. The combined relative uncertainty (Uc) and expanded uncertainty (Ue) was determined using repetitivity, recovery and calibration curves data for each pesticide.

  5. Quantitation of cocaine, benzoylecgonine, ecgonine methyl ester, and cocaethylene in urine and blood using gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Fleming, Steven W; Dasgupta, Amitava; Garg, Uttam

    2010-01-01

    Cocaine, a stimulant, is a commonly abused drug. Cocaine and its metabolites are measured in various biological specimens for clinical and forensic purposes. Urine or plasma or serum is spiked with deuterated internal standards cocaine-d3, benzoylecgonine-d3, ecgonine methyl ester-d3, and cocaethylene-d3 and buffered with phosphate buffer. The drugs in the sample are extracted by cation-exchange solid phase extraction. The drugs from the solid phase cartridge are eluted and the eluent is dried under the stream of nitrogen. The residue is incubated with pentafluoropropionic acid anhydride and pentafluoropropanol to form pentafluoropropionyl derivatives of ecgonine methyl ester and benzoylecgonine. Cocaine and cocaethylene are refractory to derivatization. The extract is dried, reconstituted in ethyl acetate, and injected into gas chromatography mass-spectrometry analyzer. Quantitation of the drugs in the samples is made, using selected ion monitoring, from a 3-point calibration curve. PMID:20077067

  6. Development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) procedure for screening of urine specimens for 100 analytes relevant in drug-facilitated crime (DFC).

    PubMed

    Remane, Daniela; Wetzel, Diana; Peters, Frank T

    2014-07-01

    In recent years, drug-facilitated crime (DFC) has become an increasing problem. A minimum list of 80 analytes to be monitored in such cases has been proposed by the Society of Forensic Toxicologists (SOFT) including the recommended minimum performance limits (RMPL). In the present study, two liquid chromatography-tandem mass spectrometry-based screening procedures, one in positive (method I) and one in negative (method II) electrospray ionization mode were developed and validated. Gradient elution was performed on a ZORBAX Eclipse XDB-C18 column after protein precipitation of the urine samples. Detection was carried out in the scheduled multiple reaction monitoring (MRM) mode monitoring two transitions per compound. A total of 100 analytes (91 basic in method I and nine acidic in method II) could be identified using the described procedure. No interferences were observed in 30 tested blank urine samples. The RMPLs were achieved for all analytes and ranged from 1 ng/mL for fentanyl to 10 μg/mL for γ-hydroxybutyrate (GHB). Matrix effects (ME) were evaluated using the same 30 urine samples and ranged from -90 % for tetrazepam to >6,000 % for the 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH). The relative standard deviations of ME were below 25 % for the vast majority of analytes. Results for urine specimens from nine authentic DFC cases were always negative with exception of drugs prescribed to the victims. Reanalysis with the developed procedure of 24 urine samples, with a positive screening result during routine clinical toxicology analysis, confirmed the routine findings. In an excretion study after a single oral doxylamine dose (30 mg), the parent drug and its nor metabolite could be detected in urine specimens from a young female volunteer for 10 days. The developed procedure allows a selective and sensitive screening of urine samples for almost all recommended analytes relevant in DFC cases. PMID:24817357

  7. Identification of known chemicals and their metabolites from Alpinia oxyphylla fruit extract in rat plasma using liquid chromatography/tandem mass spectrometry (LC-MS/MS) with selected reaction monitoring.

    PubMed

    Chen, Feng; Li, Hai-Long; Tan, Yin-Feng; Li, Yong-Hui; Lai, Wei-Yong; Guan, Wei-Wei; Zhang, Jun-Qing; Zhao, Yuan-Sheng; Qin, Zhen-Miao

    2014-08-01

    Alpinia oxyphylla (Yizhi) capsularfruits are commonly used in traditional medicine. Pharmacological studies have demonstrated that A. oxyphylla capsularfruits have some beneficial roles. Besides volatile oil, sesquiterpenes, diarylheptanoids and flavonoids are main bioactive constituents occurring in the Yizhi capsularfruits. The representative constituents include tectochrysin, izalpinin, chrysin, apigenin-4',7-dimethylether, kaempferide, yakuchinone A, yakuchinone B, oxyphyllacinol and nootkatone. Their content levels in the fruit and its pharmaceutical preparations have been reported by our group. The nine phytochemicals are also the major components present in the Yizhi alcoholic extracts, which have anti-diarrheal activities. However, the fates of these constituents in the body after oral or intravenous administration remain largely unknown. In the present study, we focus on these phytochemicals albeit other concomitant compounds. The chemicals and their metabolites in rat plasma were identified using liquid chromatography/tandem mass spectrometry with selected reaction monitoring mode after orally administered Yizhi extract to rats. Rat plasma samples were treated by methanol precipitation, acidic or enzymatic hydrolysis. This target analysis study revealed that: (1) low or trace plasma levels of parent chemicals were measured after p.o. administration of Yizhi extract, Suoquan capsules and pills to rats; (2) flavonoids and diarylheptanoids formed mainly monoglucuronide metabolites; however, diglucuronide metabolites for chrysin, izalpinin and kaempferide were also detected; (3) metabolic reduction of Yizhi diarylheptanoids occurred in rats. Yakuchinone B was reduced to yakuchinone A and then to oxyphyllacinol in a stepwise manner and subsequently glucuronidated by UDP-glucuronosyl transferase. Further research is needed to characterize the UDP-glucuronosyl transferase and reductase involved in the biotransformation of Yizhi chemicals. PMID:24879483

  8. Detection of aqueous phase chemical warfare agent degradation products by negative mode ion mobility time-of-flight mass spectrometry [IM(tof)MS].

    PubMed

    Steiner, Wes E; Harden, Charles S; Hong, Feng; Klopsch, Steve J; Hill, Herbert H; McHugh, Vincent M

    2006-02-01

    The use of negative ion monitoring mode with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer [IM(tof)MS] to detect chemical warfare agent (CWA) degradation products from aqueous phase samples has been determined. Aqueous phase sampling used a traditional electrospray ionization (ESI) source for sample introduction and ionization. Certified reference materials (CRM) of CWA degradation products for the detection of Schedule 1, 2, or 3 toxic chemicals or their precursors as defined by the chemical warfare convention (CWC) treaty verification were used in this study. A mixture of six G-series nerve related CWA degradation products (EMPA, IMPA, EHEP, IHEP, CHMPA, and PMPA) and their related collision induced dissociation (CID) fragment ions (MPA and EPA) were found in each case to be clearly resolved and detected using the IM(tof)MS instrument in negative ion monitoring mode. Corresponding ions, masses, drift times, K(o) values, and signal intensities for each of the CWA degradation products are reported. PMID:16413205

  9. Exploring Biosignatures Associated with Thenardite by Geomatrix-Assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (GALDI-FTICR-MS)

    SciTech Connect

    C. Doc Richardson; Nancy W. Hinman; Timothy R. McJunkin; J. Michelle Kotler; Jill R. Scott

    2008-10-01

    Geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) has been employed to determine how effectively bio/organic molecules associated with the mineral thenardite (Na2SO4) can be detected. GALDI is based on the ability of the mineral host to assist desorption and ionization of bio/organic molecules without additional sample preparation. When glycine was mixed with thenardite, glycine was deprotonated to produce C2H4NO-2 at m/z 74.025. The combination of stearic acid with thenardite produced a complex cluster ion at m/z 390.258 in the negative mode, which was assigned a composition ofC18H39O7Na-. Anatural sample of thenardite from Searles Lake in California also produced a peak at m/z 390.260. The bio/organic signatures in both the laboratory-based and natural samples were heterogeneously dispersed as revealed by chemical imaging. The detection limits for the stearic acid and thenardite combination were estimated to be 3 parts per trillion or~7 zeptomoles (10-21) per laser spot. Attempts to improve the signal-to-noise ratio by co-adding FTICR-MS data predetermined to contain the biosignatures of interest revealed problems due to a lack of phase coherence between data sets.

  10. Investigation of volatiles emitted from freshly cut onions (Allium cepa L.) by real time proton-transfer reaction-mass spectrometry (PTR-MS).

    PubMed

    Løkke, Mette Marie; Edelenbos, Merete; Larsen, Erik; Feilberg, Anders

    2012-11-22

    Volatile organic compounds (VOCs) in cut onions (Allium cepa L.) were continuously measured by PTR-MS during the first 120 min after cutting. The headspace composition changed rapidly due to the very reactive volatile sulfurous compounds emitted from onion tissue after cell disruption. Mass spectral signals corresponding to propanethial S-oxide (the lachrymatory factor) and breakdown products of this compound dominated 0-10 min after cutting. Subsequently, propanethiol and dipropyl disulfide predominantly appeared, together with traces of thiosulfinates. The concentrations of these compounds reached a maximum at 60 min after cutting. Propanethiol was present in highest concentrations and had an odor activity value 20 times higher than dipropyl disulfide. Thus, propanethiol is suggested to be the main source of the characteristic onion odor. Monitoring the rapid changes of VOCs in the headspace of cut onion necessitates a high time resolution, and PTR-MS is demonstrated to be a very suitable method for monitoring the headspace of freshly cut onions directly after cutting without extraction or pre-concentration.

  11. Capillary-Channeled Polymer (C-CP) Films as Processing Platforms for Protein Analysis by Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry (MALDI-MS)

    NASA Astrophysics Data System (ADS)

    Pittman, Jennifer J.; Manard, Benjamin T.; Kowalski, Paul J.; Marcus, R. Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H2O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs.

  12. Capillary-channeled polymer (C-CP) films as processing platforms for protein analysis by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS).

    PubMed

    Pittman, Jennifer J; Manard, Benjamin T; Kowalski, Paul J; Marcus, R Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H(2)O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs. PMID:22012690

  13. A reversed-phase capillary ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method for comprehensive top-down/bottom-up lipid profiling

    PubMed Central

    Gao, Xiaoli; Zhang, Qibin; Meng, Da; Issac, Giorgis; Zhao, Rui; Fillmore, Thomas L.; Chu, Rosey K.; Zhou, Jianying; Tang, Keqi; Hu, Zeping; Moore, Ronald J.; Smith, Richard D.; Katze, Michael G.; Metz, Thomas O.

    2012-01-01

    Lipidomics is a critical part of metabolomics and aims to study all the lipids within a living system. We present here the development and evaluation of a sensitive capillary UPLC-MS method for comprehensive top-down/bottom-up lipid profiling. Three different stationary phases were evaluated in terms of peak capacity, linearity, reproducibility, and limit of quantification (LOQ) using a mixture of lipid standards representative of the lipidome. The relative standard deviations of the retention times and peak abundances of the lipid standards were 0.29% and 7.7%, respectively, when using the optimized method. The linearity was acceptable at >0.99 over 3 orders of magnitude, and the LOQs were sub-fmol. To demonstrate the performance of the method in the analysis of complex samples, we analyzed lipids extracted from a human cell line, rat plasma, and a model human skin tissue, identifying 446, 444, and 370 unique lipids, respectively. Overall, the method provided either higher coverage of the lipidome, greater measurement sensitivity, or both, when compared to other approaches of global, untargeted lipid profiling based on chromatography coupled with MS. PMID:22354571

  14. Biomarker- and similarity coefficient-based approaches to bacterial mixture characterization using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)

    PubMed Central

    Zhang, Lin; Smart, Sonja; Sandrin, Todd R

    2015-01-01

    MALDI-TOF MS profiling has been shown to be a rapid and reliable method to characterize pure cultures of bacteria. Currently, there is keen interest in using this technique to identify bacteria in mixtures. Promising results have been reported with two- or three-isolate model systems using biomarker-based approaches. In this work, we applied MALDI-TOF MS-based methods to a more complex model mixture containing six bacteria. We employed: 1) a biomarker-based approach that has previously been shown to be useful in identification of individual bacteria in pure cultures and simple mixtures and 2) a similarity coefficient-based approach that is routinely and nearly exclusively applied to identification of individual bacteria in pure cultures. Both strategies were developed and evaluated using blind-coded mixtures. With regard to the biomarker-based approach, results showed that most peaks in mixture spectra could be assigned to those found in spectra of each component bacterium; however, peaks shared by two isolates as well as peaks that could not be assigned to any individual component isolate were observed. For two-isolate blind-coded samples, bacteria were correctly identified using both similarity coefficient- and biomarker-based strategies, while for blind-coded samples containing more than two isolates, bacteria were more effectively identified using a biomarker-based strategy. PMID:26537565

  15. Migration of odorous compounds from adhesives used in market samples of food packaging materials by chromatography olfactometry and mass spectrometry (GC-O-MS).

    PubMed

    Vera, Paula; Canellas, Elena; Nerín, Cristina

    2014-02-15

    Adhesives are commonly used in the manufacture of multilayer food packaging materials. Although they are not in direct contact with the packed food, their compounds may migrate from the adhesive through the substrates to the food. The aim of this work is to determine the migrant concentration in order to evaluate the possible human risk and also to determine if this migration could affect the organoleptic properties of packed food. For this purpose, a total of 12 market samples of multilayer materials (laminates) for packaging dry food (tomatoes, cakes, cookies, breadcrumbs, flour or salt) or fresh food (pizza and pastry) produced with 5 different adhesives were analysed by GC-O-MS. A total of 25 different compounds from adhesives were detected in these laminates. Seventy-six percentage of these compounds migrated into a dry food simulant (Tenax®). Furthermore, compounds with concentrations below the MS detection limit were detected by sniffers with a high modified frequency (MF%). Acetic acid, butyric acid and cyclohexanol with vinegar, cheese and camphor odours were the most abundant compounds. All migration data were below the specific migration limits (SML) and threshold toxicological concern (TTC) recommended values according to the Cramer classification.

  16. Characterization of flavonoid metabolites in rat plasma, urine, and feces after oral administration of Semen Ziziphi Spinosae extract by HPLC-diode-array detection (DAD) and ion-trap mass spectrometry (MS(n)).

    PubMed

    Bao, Kang-De; Li, Ping; Qi, Lian-Wen; Li, Hui-Jun; Yi, Ling; Wang, Wei; Wang, Ya-Qiong

    2009-02-01

    A highly specific and sensitive method using high performance liquid chromatography coupled with diode-array detection and ion-trap mass spectrometry (HPLC-DAD-MS(n)) was developed for study of the constituents of flavonoid extract of jujube seeds and the metabolites in rat plasma, urine, and feces samples after oral administration of flavonoid extract of jujube seeds. Two major flavonoids (spinosin and 6'''-feruloylspinosin) with content >60% in the flavonoid extract of jujube seeds were detected and confirmed by comparison with the reference standards. Furthermore, five metabolic components in plasma, seven in urine, and four in feces were detected and elucidated. The scientific and plausible biotransformation pathways of the main components in flavonoid extract of jujube seeds were also proposed, together with presentation of clues for potential bioactive mechanisms. This convenient HPLC-DAD-MS(n) method could be used to identify the chemical components of flavonoid extract of jujube seeds as well as their metabolites, and to reveal their possible metabolic mechanism of action in vivo. PMID:19182403

  17. Chemodiversity in the fingerprint analysis of volatile organic compounds (VOCs) of 35 old and 7 modern apple cultivars determined by proton-transfer-reaction mass spectrometry (PTR-MS) in two different seasons.

    PubMed

    Ciesa, Flavio; Höller, Irene; Guerra, Walter; Berger, Jennifer; Dalla Via, Josef; Oberhuber, Michael

    2015-05-01

    Volatile organic compounds (VOCs) are chemical species that play an important role in determining the characteristic aroma and flavor of fruits. Apple (Malus × domestica Borkh.) cultivars differ in their aroma and composition of VOCs. To determine varietal differences in the aroma profiles, VOCs emitted by 7 modern and 35 old apple cultivars were analyzed using Proton Transfer Reaction Mass Spectrometry (PTR-MS). PTR-MS is a rapid, reproducible, and non-destructive spectrometric technique for VOC analysis of single fruits, developed for direct injection analysis. In the present study, we analyzed the differences in the emission of VOCs from single fruits at harvest and after a storage period of 60±10 days, followed by 3 d of shelf life. Our results show that VOC profile differences among apple cultivars were more pronounced after storage than at harvest. Furthermore, chemodiversity was higher in old cultivars compared to modern cultivars, probably due to their greater genetic variability. Our data highlight the importance of storage and shelf life are crucial for the development of the typical aroma and flavor of several apple cultivars. The validity of the method is demonstrated by comparison of two different harvest years.

  18. Gas Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF-MS)-Based Metabolomics for Comparison of Caffeinated and Decaffeinated Coffee and Its Implications for Alzheimer’s Disease

    PubMed Central

    Chang, Kai Lun; Ho, Paul C.

    2014-01-01

    Findings from epidemiology, preclinical and clinical studies indicate that consumption of coffee could have beneficial effects against dementia and Alzheimer’s disease (AD). The benefits appear to come from caffeinated coffee, but not decaffeinated coffee or pure caffeine itself. Therefore, the objective of this study was to use metabolomics approach to delineate the discriminant metabolites between caffeinated and decaffeinated coffee, which could have contributed to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed distinct separation between the two types of coffee (cumulative Q2 = 0.998). A total of 69 discriminant metabolites were identified based on the OPLS-DA model, with 37 and 32 metabolites detected to be higher in caffeinated and decaffeinated coffee, respectively. These metabolites include several benzoate and cinnamate-derived phenolic compounds, organic acids, sugar, fatty acids, and amino acids. Our study successfully established GC-TOF-MS based metabolomics approach as a highly robust tool in discriminant analysis between caffeinated and decaffeinated coffee samples. Discriminant metabolites identified in this study are biologically relevant and provide valuable insights into therapeutic research of coffee against AD. Our data also hint at possible involvement of gut microbial metabolism to enhance therapeutic potential of coffee components, which represents an interesting area for future research. PMID:25098597

  19. Comparative performance study of different sample introduction techniques for rapid and precise selenium isotope ratio determination using multi-collector inductively coupled plasma mass spectrometry (MC-ICP/MS).

    PubMed

    Elwaer, Nagmeddin; Hintelmann, Holger

    2007-11-01

    The analytical performance of five sample introduction systems, a cross flow nebulizer spray chamber, two different solvent desolvation systems, a multi-mode sample introduction system (MSIS), and a hydride generation (LI2) system were compared for the determination of Se isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP/MS). The optimal operating parameters for obtaining the highest Se signal-to-noise (S/N) ratios and isotope ratio precision for each sample introduction were determined. The hydride generation (LI2) system was identified as the most suitable sample introduction method yielding maximum sensitivity and precision for Se isotope ratio measurement. It provided five times higher S/N ratios for all Se isotopes compared to the MSIS, 20 times the S/N ratios of both desolvation units, and 100 times the S/N ratios produced by the conventional spray chamber sample introduction method. The internal precision achieved for the (78)Se/(82)Se ratio at 100 ng mL(-1) Se with the spray chamber, two desolvation, MSIS, and the LI2 systems coupled to MC-ICP/MS was 150, 125, 114, 13, and 7 ppm, respectively. Instrument mass bias factors (K) were calculated using an exponential law correction function. Among the five studied sample introduction systems the LI2 showed the lowest mass bias of -0.0265 and the desolvation system showed the largest bias with -0.0321. PMID:17726602

  20. Evaluation of glycoalkaloids in tubers of genetically modified virus Y-resistant potato plants (var. Désirée) by non-aqueous capillary electrophoresis coupled with electrospray ionization mass spectrometry (NACE-ESI-MS).

    PubMed

    Bianco, Giuliana; Schmitt-Kopplin, Philippe; Crescenzi, Aniello; Comes, Soccorsa; Kettrup, Antonius; Cataldi, Tommaso R I

    2003-03-01

    The glycoalkaloid content of transgenic potatoes was evaluated by an optimised method based on non-aqueous capillary electrophoresis coupled on-line with electrospray ionization-mass spectrometry (NACE-ESI-MS). The potato material consisted of tubers from a conventional cv. Désirée and from three lines of modified plants resistant, intermediate and susceptible to infection by potato virus Y (PVY). The main glycoalkaloids were confirmed to be alpha-solanine and alpha-chaconine with parent ion masses m/z 852 and 868, respectively. In addition, an unknown minor peak at m/z 850.6 was found both in conventional (control) and susceptible line potato tubers. Such a compound exhibited an MS(2) spectrum with fragments ions at 704 and 396 m/z derived by loss of two ions, i.e. m/z 146 and 307, most likely corresponding to a rhamnose unit and a [glucose-(rhamnose)(2)] moiety, respectively. Up to 30-80-fold higher concentrations of total glycoalkaloids were found in the peel compared to flesh samples of all tubers examined. TGA content was nearly doubled in peel samples of resistant compared to control lines, and these levels were lower than the limit recommended for food safety, i.e. 20-60 mg of TGA per 100 g fresh weight. Moreover, it was established that tubers produced by virus-resistant clones are substantially equivalent in glycoalkaloid contents to those produced by conventional potato varieties.

  1. Multiresidue method for determination of 88 pesticides in berry fruits using solid-phase extraction and gas chromatography-mass spectrometry: Determination of 88 pesticides in berries using SPE and GC-MS.

    PubMed

    Yang, X; Zhang, H; Liu, Y; Wang, J; Zhang, Y C; Dong, A J; Zhao, H T; Sun, C H; Cui, J

    2011-07-15

    A method using solid phase extraction (SPE) cleanup followed by gas chromatography-mass spectrometry (GC-MS) has been established for quantitative determination of 88 pesticide residues in berry fruits including raspberry, strawberry, blueberry and grape. Based on an appraisal of the characteristics of GC-MS, validation experiments were conducted for 88 pesticides. In the method, solid-phase extraction was carried out using Envi-Carb cartridge coupled with NH(2)-LC cartridge with acetonitrile-toluene (3:1, v/v) as the eluted solvent. In the linear range of each pesticide, the correlation coefficient was R(2)⩾0.99. At the low, medium and high three fortification levels of 0.05-0.5mgkg(-1), recoveries fell within 63-137%. The relative standard deviation was between 1% and 19% for all 88 pesticides. Low limits of detection (0.006-0.05mgkg(-1)) and quantification (0.02-0.15mgkg(-1)) were readily achieved with this method for all tested pesticides. PMID:23140746

  2. Analysis of benzophenone and 4-methylbenzophenone in breakfast cereals using ultrasonic extraction in combination with gas chromatography-tandem mass spectrometry (GC-MS(n)).

    PubMed

    Van Hoeck, E; De Schaetzen, T; Pacquet, C; Bolle, F; Boxus, L; Van Loco, J

    2010-03-17

    Benzophenone (BP) and 4-methylbenzophenone (4MBP) are photo-initiators that are generally used to cure ink on carton boards. In this contribution, a fast and reliable method for the determination of BP and 4MBP in breakfast cereals is described. The sample was extracted ultrasonically using a mixture of dichloromethane and acetonitrile (1:1), followed by a clean-up of the extract using solid phase extraction with a silica cartridge. Finally, the extract was analysed by GC-MS(n). Benzophenone-d(10) was used as internal standard. The presented method is validated in terms of linearity, recovery, repeatability and intra-laboratory reproducibility, specificity, limit of detection and limit of quantification. In conclusion, this method is able to detect both BP and 4MBP at very low concentrations (LOD=2microg kg(-1)) in breakfast cereals.

  3. Ion Mobility Measurements of Nondenatured 12-150 kDa Proteins and Protein Multimers by Tandem Differential Mobility Analysis-Mass Spectrometry (DMA-MS)

    NASA Astrophysics Data System (ADS)

    Hogan, Christopher J.; de la Mora, Juan Fernández

    2011-01-01

    The mobilities of electrosprayed proteins and protein multimers with molecular weights ranging from 12.4 kDa (cytochrome C monomers) to 154 kDa (nonspecific concanavalin A hexamers) were measured in dry air by a planar differential mobility analyzer (DMA) coupled to a time-of-flight mass spectrometer (TOF-MS). The DMA determines true mobility at atmospheric pressure, without perturbing ion structure from that delivered by the electrospray. A nondenaturing aqueous 20 mM triethylammonium formate buffer yields compact ions with low charge states, moderating polarization effects on ion mobility. Conversion of mobilities into cross-sections involves a reduction factor ξ for the actual mobility relative to that associated with elastic specular collisions with smooth surfaces. ξ is known to be 1.36 in air from Millikan's oil drop experiments. A similar enhancement effect ascribed to atomic-scale surface roughness has been found in numerical simulations. Adopting Millikan's value ξ = 1.36 and assuming a spherical geometry yields a gas-phase protein density ρ p = 0.949 ± 0.053 g cm-3 for all our protein data. This is substantially higher than the 0.67 g cm-3 found in recent low-resolution DMA measurements of singly charged proteins. DMA-MS can distinguish nonspecific protein aggregates formed during the electrospray process from those formed preferentially in solution. The observed charge versus diameter relation is compatible with a protein charge reduction mechanism based on the evaporation of triethylammonium ions from electrosprayed drops.

  4. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS): Progress report, September 1, 1985-August 31, 1988

    SciTech Connect

    Browner, R.F.

    1988-05-01

    Technical advances have been made through a number of careful and detailed studies of fundamental processes occurring within the interface. These have led to great improvements in the performance of the interface, many of which are detailed below. Of particular importance has been an improvement in detection capabilities, allowing full-scan (40--400 daltons) electron impact mass spectra to be obtained with only approximately 5 ng of material injected on column. Selected ion monitoring gives detection limits in the range of 100 pg. These figures are particularly noteworthy because they represent values within a factor of 3 of the lowest detection limits possible with the same instrument when used in a GC/MS mode. The full range of compound types accessible with the MAGIC-LC/MS interface has not been fully investigated. In general terms, all compounds which are known to be capable of generating EI and CI spectra and which have been tried with the interface have generated good quality spectra. These include carbamate and triazine pesticides, phenyl urea herbicides, polynuclear aromatic hydrocarbons, plant alkaloids, antioxidants and EPA Appendix 8 compounds. Compounds known not to generate EI spectra, such as simple sugars and certain azo dyes, predictably do not generate spectra with the current system. The primary mode of ion formation appears to be through a flash vaporization step in the ion source, followed by EI or CI ionization, as selected. It is possible to generate good searchable EI spectra with strong molecular ions even for quite involatile species. An example is provided by reserpine, with a molecular weight of 608 daltons, which generates a searchable EI spectrum with a strong molecular ion at m/z 608. 11 refs.

  5. On-line chemical vapour generation of cadmium in the presence of hexacyanochromate(III) for determination by inductively coupled plasma mass spectrometry (ICP-MS)

    PubMed Central

    Yilmaz, Vedat; Rose, LaKeysha; Little, Maria D.

    2012-01-01

    A vapour generation (VG) procedure has been described for determination of Cd by ICP-MS. Volatile species of Cd were generated on-line by interacting acidic sample solution containing potassium hexacyanochromate(III), K3Cr(CN)6, with sodium borohydride (NaBH4). The hexacyanochromate(III) complex was generated on-line by reacting 0.04 mol L−1 chromium(III) nitrate and 0.16 mol L−1 potassium cyanide (KCN) solutions in water. The resulting suspension of chromium(III) hydroxide, Cr(OH)3, was fed continuously to acidic stream of sample solution in the presence of excess KCN. The experimental conditions were optimized for effective generation of volatile species of Cd. Optimum signals were obtained from reaction of sample solutions in 4% v/v HCl with 2% m/v NaBH4 solution. Presence of K3Cr(CN)6 improved the efficiency of Cd vapour generation substantially affording 15-fold higher sensitivity. This phenomenon was thought to occur through formation of reactive intermediates evolved from interaction of [Cr(CN)6]3− with NaBH4 that react with Cd(II) to increase the yield volatile Cd species. Under the optimum conditions, no significant interferences were observed from the transition metals, including Cu and Ni, up to 1.0 μg mL−1 levels. Among the hydride forming elements, Bi, Pb, Sb and Sn depressed the signals above 0.1 μg mL−1. The detection limits (3s) were 6.2 and 5.2 ng L−1 for 110Cd and 111Cd isotopes, respectively. The method was successfully applied to determination of Cd by ICP-MS in several certified reference materials, including Nearshore seawater (CASS-4), Bone ash (SRM 1400), Dogfish liver (DOLT-4) and Mussel tissue (SRM 2976). PMID:23997384

  6. Fecal metabonomic study of a polysaccharide, MDG-1 from Ophiopogon japonicus on diabetic mice based on gas chromatography/time-of-flight mass spectrometry (GC TOF/MS).

    PubMed

    Zhu, Yunyun; Cong, Wenjuan; Shen, Lan; Wei, Hai; Wang, Yuan; Wang, Lingyi; Ruan, Kefeng; Wu, Fei; Feng, Yi

    2014-02-01

    Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disorder with systemic complications and has been a worldwide epidemic. Ophiopogon japonicus is a traditional Chinese medicine used to treat diabetes for thousands of years. From our previous work, we know that MDG-1, a water-soluble β-D-fructan polysaccharide from O. japonicas could treat T2DM experimentally. However, MDG-1 is poorly absorbed and its mechanism of action is still unknown. Therefore, a GC TOF/MS-based metabonomic approach in combination with multivariate statistical analysis was performed to investigate the mechanism of MDG-1 in a spontaneous diabetic model. Female diabetic KKay mice (21 weeks old) were randomly divided into a diabetic group (n = 6, gavaged with distilled water) and a MDG-1-Diabetic group (n = 7, gavaged with MDG-1, 300 mg kg(-1)) and female C57BL/6 mice (21 weeks old) were set as controls (n = 6, gavaged with distilled water). After 8-weeks of treatment, feces samples were collected for GC-TOF/MS analysis. Consequently, 12 potential biomarkers were identified, including monosugars (D-tagatose, D-lyxose, D-erythrose, xylo-hexos-5-ulose, 2-deoxy-galactose), butanedioic acid, amino acids (phenylalanine, L-lysine, L-methionine, L-aspartic acid) and purine derivatives (7H-purine, 2'-deoxyinosine). We assume the monosugars and butanedioic acid were the fermentation products of MDG-1 by intestinal microbes and MDG-1 actions against diabetes might be accomplished through the absorbable monosugars and butanedioic acid via suppressing intestinal glucose absorption, enhancing liver glycogenesis, inhibiting glycogenolysis and promoting GLP-1 secretion. Besides, MDG-1 might alleviate diabetes and diabetic nephropathy by reducing 7H-purine and 2'-deoxyinosine. Further omics-driven studies including genomics, proteomics and metabonomics were considered to be carried out to provide direct evidence of gut microbiome contribution to MDG-1 actions.

  7. New method to determine free sterols/oxysterols in food matrices using gas chromatography and ion trap mass spectrometry (GC-IT-MS).

    PubMed

    Szterk, Arkadiusz; Pakuła, Lucyna

    2016-05-15

    Sterols/oxysterols in food may be free or bound i.e. esterified with fatty acids. Methods commonly applied to determine those compounds in such matrices (based on various analytical techniques) usually start with hydrolysis of the food lipid fraction, which means that the results are no good indication of concentration of free sterols/oxysterols only. But only free oxysterols are proatherogenic factors, bound ones are not. There are some published methods selectively sensitive to free oxysterols only, but they are capable to determine only a few compounds and feature very low recovery rates. The aim of this work was to develop a method to determine various free (non-esterified) sterols/oxysterols in various food matrices. The developed method is based on the GC-IT-MS technique used in the chemical ionization mode. It was applied to determine 16 different free sterols/oxysterols in egg powder, cheese, butter, milk and salami. Fat extracted from the given matrix is purified on a specially prepared silica-gel bed to separate the sterol fraction from the oxysterol one. Sterols are silylated using N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane BSTFA:TMCS, then GC-IT-MS analysed. The method features high recovery rates (75-95%), high reproducibility (RSD<20%), and sensitivity within the 0.01-0.3 mg 100 g(-1) range, depending on the analysed compound. The method is ideally suited for determination of free sterols/oxysterols. Besides, should total concentration of both free and bound forms be of interest, food lipids may be transesterificated before the silica-gel bed purification step.

  8. New method to determine free sterols/oxysterols in food matrices using gas chromatography and ion trap mass spectrometry (GC-IT-MS).

    PubMed

    Szterk, Arkadiusz; Pakuła, Lucyna

    2016-05-15

    Sterols/oxysterols in food may be free or bound i.e. esterified with fatty acids. Methods commonly applied to determine those compounds in such matrices (based on various analytical techniques) usually start with hydrolysis of the food lipid fraction, which means that the results are no good indication of concentration of free sterols/oxysterols only. But only free oxysterols are proatherogenic factors, bound ones are not. There are some published methods selectively sensitive to free oxysterols only, but they are capable to determine only a few compounds and feature very low recovery rates. The aim of this work was to develop a method to determine various free (non-esterified) sterols/oxysterols in various food matrices. The developed method is based on the GC-IT-MS technique used in the chemical ionization mode. It was applied to determine 16 different free sterols/oxysterols in egg powder, cheese, butter, milk and salami. Fat extracted from the given matrix is purified on a specially prepared silica-gel bed to separate the sterol fraction from the oxysterol one. Sterols are silylated using N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane BSTFA:TMCS, then GC-IT-MS analysed. The method features high recovery rates (75-95%), high reproducibility (RSD<20%), and sensitivity within the 0.01-0.3 mg 100 g(-1) range, depending on the analysed compound. The method is ideally suited for determination of free sterols/oxysterols. Besides, should total concentration of both free and bound forms be of interest, food lipids may be transesterificated before the silica-gel bed purification step. PMID:26992495

  9. Chromium in rivers impacted by tannery wastes determined by high performance liquid chromatography - inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pereira de Abreu, M.-H.; Vignati, D.; Dominik, J.

    2003-05-01

    The total chromium concentrations by ICP-MS and HPLC-ICP-MS and the redox chromium species have been determined in rivers impacted by untreated wastes from tanneries at Fès (Morocco). The results obtained by two ICP-MS analysis methods showed significantly different chromium values at m/z 53. The higher values obtained with external calibration, can be attributed to matrix effects, especially ^{37}Cl ^{16}O at m/z 53. This is confirmed on the chromatograms by the presence of a peak at 100s with the anomalous ^{52}Cr/^{53}Cr isotopic ratio. The hexavalent chromium was not detected. Two trivalent chromium monomer species, Cr(OH)(H2O)5^{2+} and Cr(H2O)6^{3+}, were present in low concentrations. We suppose that the major part of chromium occurred as Cr(III) polymeric species which were not retained on the column. These Cr(III) forms are usually complexed with Cl^- or/and SO4^{2-}, used as tanning agents.

  10. Independent assessment of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) sample preparation quality: A novel statistical approach for quality scoring.

    PubMed

    Kooijman, Pieter C; Kok, Sander J; Weusten, Jos J A M; Honing, Maarten

    2016-05-01

    Preparation of samples according to an optimized method is crucial for accurate determination of polymer sample characteristics by Matrix-Assisted Laser Desorption Ionization (MALDI) analysis. Sample preparation conditions such as matrix choice, cationization agent, deposition technique or even the deposition volume should be chosen to suit the sample of interest. Many sample preparation protocols have been developed and employed, yet finding the optimal sample preparation protocol remains a challenge. Because an objective comparison between the results of diverse protocols is not possible, "gut-feeling" or "good enough" is often decisive in the search for an optimum. This implies that sub-optimal protocols are used, leading to a loss of mass spectral information quality. To address this problem a novel analytical strategy based on MALDI imaging and statistical data processing was developed in which eight parameters were formulated to objectively quantify the quality of sample deposition and optimal MALDI matrix composition and finally sum up to an overall quality score of the sample deposition. These parameters can be established in a fully automated way using commercially available mass spectrometry imaging instruments without any hardware adjustments. With the newly developed analytical strategy the highest quality MALDI spots were selected, resulting in more reproducible and more valuable spectra for PEG in a variety of matrices. Moreover, our method enables an objective comparison of sample preparation protocols for any analyte and opens up new fields of investigation by presenting MALDI performance data in a clear and concise way.

  11. A Metabolomic Approach to Clarifying the Effect of AST-120 on 5/6 Nephrectomized Rats by Capillary Electrophoresis with Mass Spectrometry (CE-MS)

    PubMed Central

    Akiyama, Yasutoshi; Takeuchi, Yoichi; Kikuchi, Koichi; Mishima, Eikan; Yamamoto, Yasuaki; Suzuki, Chitose; Toyohara, Takafumi; Suzuki, Takehiro; Hozawa, Atsushi; Ito, Sadayoshi; Soga, Tomoyoshi; Abe, Takaaki

    2012-01-01

    The oral adsorbent AST-120 is composed of spherical carbon particles and has an adsorption ability for certain small-molecular-weight compounds that accumulate in patients with chronic kidney disease (CKD). So far, very few compounds are known to be adsorbed by AST-120 in vivo. To examine the effect of AST-120 in vivo, we comprehensively evaluated the plasma concentrations of 146 compounds (61 anions and 85 cations) in CKD model rats, with or without four weeks of treatment with AST-120. By capillary electrophoresis with mass spectrometry, we identified 6 anions and 17 cations that were significantly decreased by AST-120 treatment. In contrast, we also identified 2 cations that were significantly increased by AST-120. Among them, 4 anions, apart from indoxyl sulfate and hippurate, and 19 cations were newly identified in this study. The plasma levels of N-acetyl-neuraminate, 4-pyridoxate, 4-oxopentanoate, glycine, γ-guanidinobutyrate, N-γ-ethylglutamine, allantoin, cytosine, 5-methylcytosine and imidazole-4-acetate were significantly increased in the CKD model compared with the sham-operated group, and were significantly decreased by AST-120 treatment. Therefore, these 10 compounds could be added as uremic compounds that indicate the effect of AST-120 treatment. This study provides useful information not only for identifying the indicators of AST-120, but also for clarifying changes in the metabolic profile by AST-120 treatment in the clinical setting. PMID:23202318

  12. Direct analysis in real time-mass spectrometry (DART-MS) for rapid qualitative screening of toxic glycols in glycerin-containing products.

    PubMed

    Self, Randy L

    2013-06-01

    In 2007, the United States Food and Drug Administration released guidance recommending testing of glycerin used in regulated consumer products, such as cough syrup preparations, toothpaste, and other pharmaceutical and food products, for the toxic compounds ethylene glycol and diethylene glycol. Regulatory laboratories routinely test glycerin, and products containing glycerin or related compounds for these toxic glycols, using an official gas chromatographic method, to ensure the safety of these products. The current work describes a companion technique to compliment this GC-FID method utilizing Orbitrap mass spectrometry with direct analysis in real time ionization to rapidly screen these samples qualitatively, with results in as little as five seconds, with no sample preparation required. This allows the more time and resource intensive method to be reserved for those rare cases when these compounds are detected, potentially greatly improving laboratory efficiency. The technique was evaluated for qualitative sensitivity and repeatability, and compared against the GC-FID method. The method appears to perform well against these metrics. PMID:23584076

  13. Ferrocenoyl piperazide as derivatizing agent for the analysis of isocyanates and related compounds using liquid chromatography/electrochemistry/mass spectrometry (LC/EC/MS).

    PubMed

    Seiwert, Bettina; Henneken, Hartmut; Karst, Uwe

    2004-12-01

    Ferrocenoyl piperazide is introduced as a new pre-column derivatizing agent for the analysis of various isocyanates in air samples using reversed-phase liquid chromatographic separation, electrochemical oxidation/ionization, and mass spectrometry. The nonpolar derivatives can be separated well using a phenyl-modified stationary phase and a formic acid/ammonium formate buffer of pH 3, which yields excellent separations, especially for one problematic group of isocyanates consisting of 2,4- and 2,6-toluylenediisocyanate (2,4- and 2,6-TDI) and hexamethylenediisocyanate (HDI). Electrochemical oxidation at low potentials (0.5 V versus Pd/H(2)) leads to formation of charged products, which are nebulized in a commercial atmospheric pressure chemical ionization (APCI) source, with the corona discharge operated only at low voltage. Limits of detection between 6 and 20 nmol/L are obtained for the isocyanate derivatives, and calibration is linear over at least two decades of concentration. The method is applied for the analysis of air after thermal degradation of a polyurethane foam, and it is demonstrated that it is suitable as well for the analysis of carboxylic acid chlorides and of isothiocyanates.