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Sample records for em aquidauana ms

  1. The E-MS Algorithm: Model Selection with Incomplete Data.

    PubMed

    Jiang, Jiming; Nguyen, Thuan; Rao, J Sunil

    2015-04-04

    We propose a procedure associated with the idea of the E-M algorithm for model selection in the presence of missing data. The idea extends the concept of parameters to include both the model and the parameters under the model, and thus allows the model to be part of the E-M iterations. We develop the procedure, known as the E-MS algorithm, under the assumption that the class of candidate models is finite. Some special cases of the procedure are considered, including E-MS with the generalized information criteria (GIC), and E-MS with the adaptive fence (AF; Jiang et al. 2008). We prove numerical convergence of the E-MS algorithm as well as consistency in model selection of the limiting model of the E-MS convergence, for E-MS with GIC and E-MS with AF. We study the impact on model selection of different missing data mechanisms. Furthermore, we carry out extensive simulation studies on the finite-sample performance of the E-MS with comparisons to other procedures. The methodology is also illustrated on a real data analysis involving QTL mapping for an agricultural study on barley grains.

  2. Biostratigraphy and paleoecology of an unusual palynological record from the Aquidauana Formation, Late Pennsylvanian of Paraná Basin.

    PubMed

    Souza, Paulo A; Perinotto, José A J; Félix, Cristina M; Araújo, Bruno C

    2015-01-01

    The Aquidauana Formation is a Permo-Carboniferous sedimentary unit, widely stratigraphicaly distributed in the northwestern and northern portions of the Paraná Basin. However, little paleontological data is available from this formation, preventing accurate biostratigraphic and paleoecological interpretations. An abundant, diversified and well preserved assemblage of palynomorphs was recognized from sampling conducted in an outcrop section in Cipolândia District of Aquidauana Municipality, state of Mato Grosso do Sul, Brazil. A total of 35 indigenous palynomorph taxa was recognized, comprising 6 species of spores (related to 5 genera), 28 species of pollen grains (14 genera) and 1 species of chlorophycean algae. Monosaccate pollen grains are exceptionally dominant, representing 90.38% of the association, particularly constituted by species of the genera Cannanoropollis (30.41% of the total assemblage), Potonieisporites (28.14%) and Plicatipollenites (19.52%). This quantitative overrepresentation is not usual from Gondwana deposits, revealing a particular plant dominance of Cordaitales in the terrestrial flora. These results are interpreted as an upland ecology characterized by plants with a moisture-independent reproduction strategy, under a glacial climate influence. Certain species of pollen allow assignment of this assemblage to the Crucisaccites monoletus Zone (Late Pennsylvanian), which had been recognized only in the middle portion of the Itararé Group at the northeastern margin of the basin.

  3. SAND FLIES (DIPTERA: PSYCHODIDAE) IN AN ENDEMIC AREA OF LEISHMANIASIS IN AQUIDAUANA MUNICIPALITY, PANTANAL OF MATO GROSSO DO SUL , BRAZIL.

    PubMed

    Figueiredo, Helen Rezende de; Santos, Mirella Ferreira da Cunha; Casaril, Aline Etelvina; Infran, Jucelei Oliveira de Moura; Ribeiro, Leticia Moraes; Fernandes, Carlos Eurico Dos Santos; Oliveira, Alessandra Gutierrez de

    2016-12-08

    The Aquidauana municipality is considered an endemic area of leishmaniasis and an important tourist site in Mato Grosso do Sul State. The aim of this study was to investigate the sand fly fauna in the city of Aquidauana. Captures were carried out twice a month, from April 2012 to March 2014 with automatic light traps and active aspiration, in the peridomicile and domicile of six residences. A total of 9,338 specimens were collected, 3,179 and 6,159 using light traps and active aspiration, respectively. The fauna consisted of: Brumptomyia brumpti, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. orcyi, Ev. sallesi, Ev. termitophila, Ev. walkeri, Lutzomyia longipalpis and Psathyromyia bigeniculata. The most abundant species captured was Lutzomyia longipalpis, present in all the ecotopes, predominantly in peridomicile areas, and mainly males. Leishmania DNA was not detected in the insects. It was observed the abundance of the sand fly fauna in the region, as well as the high frequency of Lu. longipalpis, the main vector of L. infantum. The results of this study show the need to increase the monitoring and more effective control measures. It is noteworthy that the studied region presents several activities related to tourism and recreation, increasing the risk of transmission of leishmaniasis to this particular human population.

  4. SAND FLIES (DIPTERA: PSYCHODIDAE) IN AN ENDEMIC AREA OF LEISHMANIASIS IN AQUIDAUANA MUNICIPALITY, PANTANAL OF MATO GROSSO DO SUL , BRAZIL

    PubMed Central

    de FIGUEIREDO, Helen Rezende; SANTOS, Mirella Ferreira da Cunha; CASARIL, Aline Etelvina; INFRAN, Jucelei Oliveira de Moura; RIBEIRO, Leticia Moraes; FERNANDES, Carlos Eurico dos Santos; de OLIVEIRA, Alessandra Gutierrez

    2016-01-01

    SUMMARY The Aquidauana municipality is considered an endemic area of leishmaniasis and an important tourist site in Mato Grosso do Sul State. The aim of this study was to investigate the sand fly fauna in the city of Aquidauana. Captures were carried out twice a month, from April 2012 to March 2014 with automatic light traps and active aspiration, in the peridomicile and domicile of six residences. A total of 9,338 specimens were collected, 3,179 and 6,159 using light traps and active aspiration, respectively. The fauna consisted of: Brumptomyia brumpti, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. orcyi, Ev. sallesi, Ev. termitophila, Ev. walkeri, Lutzomyia longipalpis and Psathyromyia bigeniculata. The most abundant species captured was Lutzomyia longipalpis, present in all the ecotopes, predominantly in peridomicile areas, and mainly males. Leishmania DNA was not detected in the insects. It was observed the abundance of the sand fly fauna in the region, as well as the high frequency of Lu. longipalpis, the main vector of L. infantum. The results of this study show the need to increase the monitoring and more effective control measures. It is noteworthy that the studied region presents several activities related to tourism and recreation, increasing the risk of transmission of leishmaniasis to this particular human population. PMID:27982353

  5. The influence of effective microorganisms (EM) and yeast on the degradation of strobilurins and carboxamides in leafy vegetables monitored by LC-MS/MS and health risk assessment.

    PubMed

    Wołejko, Elżbieta; Łozowicka, Bożena; Kaczyński, Piotr; Jankowska, Magdalena; Piekut, Jolanta

    2016-01-01

    The aim of this study was to determine the behaviour of strobilurin and carbocyamides commonly used in chemical protection of lettuce depending on carefully selected effective microorganisms (EM) and yeast (Y). Additionally, the assessment of the chronic health risk during a 2-week experiment was performed. The statistical method for correlation of physico-chemical parameters and time of degradation for pesticides was applied. In this study, the concentration of azoxystrobin, boscalid, pyraclostrobin and iprodione using liquid chromatography-mass spectrometry (LC-MS/MS) in the matrix of lettuce plants was performed, and there was no case of concentration above maximum residues levels. Before harvest, four fungicides and their mixture with EM (1 % and 10 %) and/or yeast 5 % were applied. In our work, the mixtures of 1%EM + Y and 10%EM + Y both stimulated and inhibited the degradation of the tested active substances. Adding 10%EM to the test substances strongly inhibited the degradation of iprodione, and its concentration decreased by 30 %, and in the case of other test substances, the degradation was approximately 60 %. Moreover, the addition of yeast stimulated the distribution of pyraclostrobin and boscalid in lettuce leaves. The risk assessment for the pesticides ranged from 0.4 to 64.8 % on day 1, but after 14 days, it ranged from 0.0 to 20.9 % for children and adults, respectively. It indicated no risk of adverse effects following exposure to individual pesticides and their mixtures with EM and yeast.

  6. Pediatric MS

    MedlinePlus

    ... with Others on MSconnection.org Join a Local Support Group Ask an MS Navigator Edward M. Dowd Personal ... navigate the school system through the Pediatric MS Support Group . Treating pediatric MS Studies have shown that the ...

  7. 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.

  8. Sensitivity of GC-EI/MS, GC-EI/MS/MS, LC-ESI/MS/MS, LC-Ag(+) CIS/MS/MS, and GC-ESI/MS/MS for analysis of anabolic steroids in doping control.

    PubMed

    Cha, Eunju; Kim, Sohee; Kim, Ho Jun; Lee, Kang Mi; Kim, Ki Hun; Kwon, Oh-Seung; Lee, Jaeick

    2015-01-01

    This study compared the sensitivity of various separation and ionization methods, including gas chromatography with an electron ionization source (GC-EI), liquid chromatography with an electrospray ionization source (LC-ESI), and liquid chromatography with a silver ion coordination ion spray source (LC-Ag(+) CIS), coupled to a mass spectrometer (MS) for steroid analysis. Chromatographic conditions, mass spectrometric transitions, and ion source parameters were optimized. The majority of steroids in GC-EI/MS/MS and LC-Ag(+) CIS/MS/MS analysis showed higher sensitivities than those obtained with other analytical methods. The limits of detection (LODs) of 65 steroids by GC-EI/MS/MS, 68 steroids by LC-Ag(+) CIS/MS/MS, 56 steroids by GC-EI/MS, 54 steroids by LC-ESI/MS/MS, and 27 steroids by GC-ESI/MS/MS were below cut-off value of 2.0 ng/mL. LODs of steroids that formed protonated ions in LC-ESI/MS/MS analysis were all lower than the cut-off value. Several steroids such as unconjugated C3-hydroxyl with C17-hydroxyl structure showed higher sensitivities in GC-EI/MS/MS analysis relative to those obtained using the LC-based methods. The steroids containing 4, 9, 11-triene structures showed relatively poor sensitivities in GC-EI/MS and GC-ESI/MS/MS analysis. The results of this study provide information that may be useful for selecting suitable analytical methods for confirmatory analysis of steroids.

  9. Progressive-Relapsing MS (PRMS)

    MedlinePlus

    ... to navigation Skip to content Menu Navigation National Multiple Sclerosis Society Sign In In Your Area Donate Donate ... of MS What Causes MS? Who Gets MS? Multiple Sclerosis FAQs Types of MS Related Conditions Symptoms & Diagnosis ...

  10. Ms. Mentor Unmasked

    ERIC Educational Resources Information Center

    Krebs, Paula

    2008-01-01

    This article presents an interview with Emily Toth, who writes the monthly "Ms. Mentor" academic advice column in the "Chronicle of Higher Education" and teaches in the English department at Louisiana State University, in Baton Rouge. She is the author of "Ms. Mentor's Impeccable Advice for Women in Academia" (1997), "Inside Peyton Place: The Life…

  11. Living with Advanced MS

    MedlinePlus

    ... more progressive disease course. Taking these factors into account can help you and your family plan more effectively for the future. Identifying options The key message to anyone living with advanced MS is ...

  12. Glossary of MS Terms

    MedlinePlus

    ... Nutrition Exercise Emotional Health Smoking Sleep Alcohol Heat & Temperature Sensitivity Travel and Recreation Managing MS and Another ... disease symptoms, resulting from an elevation in body temperature or other stressor (e.g., an infection, severe ...

  13. MS Based Metabonomics

    SciTech Connect

    Want, Elizabeth J.; Metz, Thomas O.

    2010-03-01

    Metabonomics is the latest and least mature of the systems biology triad, which also includes genomics and proteomics, and has its origins in the early orthomolecular medicine work pioneered by Linus Pauling and Arthur Robinson. It was defined by Nicholson and colleagues in 1999 as the quantitative measurement of perturbations in the metabolite complement of an integrated biological system in response to internal or external stimuli, and is often used today to describe many non-global types of metabolite analyses. Applications of metabonomics are extensive and include toxicology, nutrition, pharmaceutical research and development, physiological monitoring and disease diagnosis. For example, blood samples from millions of neonates are tested routinely by mass spectrometry (MS) as a diagnostic tool for inborn errors of metabolism. The metabonome encompasses a wide range of structurally diverse metabolites; therefore, no single analytical platform will be sufficient. Specialized sample preparation and detection techniques are required, and advances in NMR and MS technologies have led to enhanced metabonome coverage, which in turn demands improved data analysis approaches. The role of MS in metabonomics is still evolving as instrumentation and software becomes more sophisticated and as researchers realize the strengths and limitations of current technology. MS offers a wide dynamic range, high sensitivity, and reproducible, quantitative analysis. These attributes are essential for addressing the challenges of metabonomics, as the range of metabolite concentrations easily exceeds nine orders of magnitude in biofluids, and the diversity of molecular species ranges from simple amino and organic acids to lipids and complex carbohydrates. Additional challenges arise in generating a comprehensive metabolite profile, downstream data processing and analysis, and structural characterization of important metabolites. A typical workflow of MS-based metabonomics is shown in Figure

  14. 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.

  15. ICP-MS Workshop

    SciTech Connect

    Carman, April J.; Eiden, Gregory C.

    2014-11-01

    This is a short document that explains the materials that will be transmitted to LLNL and DNN HQ regarding the ICP-MS Workshop held at PNNL June 17-19th. The goal of the information is to pass on to LLNL information regarding the planning and preparations for the Workshop at PNNL in preparation of the SIMS workshop at LLNL.

  16. NAPS-MS

    PubMed Central

    Gudesblatt, Mark; Kresa-Reahl, Kiren; Brandes, David W.; Sater, Pamela

    2016-01-01

    Background: Patients with multiple sclerosis (MS) have higher rates of fatigue, mood disturbance, and cognitive impairments than healthy populations. Disease-modifying agents may affect sleep. Although patients taking natalizumab often show improvement in fatigue during the first year of therapy, the mechanism behind this effect is unknown. The aim of the NAPS-MS study was to investigate whether natalizumab affected objective measures of sleep as determined by polysomnography (PSG) and multiple sleep latency testing (MSLT) in patients with MS with fatigue or sleepiness initiating therapy. Additional goals were to evaluate changes in measures of fatigue, mood, and cognition and to correlate these measures with objective sleep measures. Methods: Patients underwent PSG and MSLT before their first natalizumab infusion and after their seventh. Patients completed the Modified Fatigue Impact Scale, Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and visual analogue scale for fatigue (VAS-F) at their first, fourth, and seventh natalizumab infusions. NeuroTrax cognitive tests and the Hospital Anxiety and Depression Scale (HADS) were performed at the first and seventh natalizumab infusions. Results: Changes in sleep efficiency, wakefulness after sleep onset, and multiple sleep latency from baseline to 6 months of therapy did not reach significance. The FSS, VAS-F, ESS, and HADS scores were significantly improved after 6 months of therapy; cognitive scores were not significantly improved. Conclusions: Although treatment with natalizumab was associated with improvements in fatigue, sleepiness, and mood, changes in objective measures of sleep were not significant. PMID:27551242

  17. MS-DIAL: data-independent MS/MS deconvolution for comprehensive metabolome analysis.

    PubMed

    Tsugawa, Hiroshi; Cajka, Tomas; Kind, Tobias; Ma, Yan; Higgins, Brendan; Ikeda, Kazutaka; Kanazawa, Mitsuhiro; VanderGheynst, Jean; Fiehn, Oliver; Arita, Masanori

    2015-06-01

    Data-independent acquisition (DIA) in liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS) provides comprehensive untargeted acquisition of molecular data. We provide an open-source software pipeline, which we call MS-DIAL, for DIA-based identification and quantification of small molecules by mass spectral deconvolution. For a reversed-phase LC-MS/MS analysis of nine algal strains, MS-DIAL using an enriched LipidBlast library identified 1,023 lipid compounds, highlighting the chemotaxonomic relationships between the algal strains.

  18. Polyamine analysis by LC-MS.

    PubMed

    Häkkinen, Merja R

    2011-01-01

    This chapter describes a protocol to analyze polyamines without any derivatization steps utilizing LC-MS/MS. Polyamines are separated by reversed phase LC prior MS analysis using heptafluorobutyric acid as MS compatible volatile ion-pairing agent, and selective and sensitive MS detection is performed using MS/MS in selected reaction monitoring mode.

  19. Relapsing-Remitting MS (RRMS)

    MedlinePlus Videos and Cool Tools

    ... Information Advanced Care Needs Employment Resources for Specific Populations Find Programs & Services in Your Area Living Well with MS Health and Wellness Family and Relationships Mobility & Accessibility Personal ...

  20. MS Thornton and MS Gardner conduct DSO 410 on middeck

    NASA Technical Reports Server (NTRS)

    1983-01-01

    On middeck, Mission Specialist (MS) Thornton, his head surrounded by wiring and with electrodes attached to his face and forehead, controls instrument switch as MS Gardner, wearing headset, signals with his thumb. Procedures are part of Detailed Supplementary Objective (DSO) 410 - Audiometry. Forward lockers and starboard wall with field sequential (FS) crew cabin camera, sleep restraints, and net stowage bag appear in background.

  1. Determination of Glyphosate Levels in Breast Milk Samples from Germany by LC-MS/MS and GC-MS/MS.

    PubMed

    Steinborn, Angelika; Alder, Lutz; Michalski, Britta; Zomer, Paul; Bendig, Paul; Martinez, Sandra Aleson; Mol, Hans G J; Class, Thomas J; Pinheiro, Nathalie Costa

    2016-02-17

    This study describes the validation and application of two independent analytical methods for the determination of glyphosate in breast milk. They are based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively. For LC-MS/MS, sample preparation involved an ultrafiltration followed by chromatography on an anion exchange column. The analysis by GC-MS/MS involved an extraction step, cleanup on a cation exchange column, and derivatization with heptafluorobutanol and trifluoroacetic acid anhydride. Both methods were newly developed for breast milk and are able to quantify glyphosate residues at concentrations as low as 1 ng/mL. The methods were applied to quantify glyphosate levels in 114 breast milk samples, which had been collected from August to September of 2015 in Germany. The mothers participated at their own request and thus do not form a representative sample. In none of the investigated samples were glyphosate residues above the limit of detection found.

  2. METLIN: MS/MS metabolite data from the MAGGIE Project

    DOE Data Explorer

    METLIN is a metabolite database for metabolomics containing over 50,000 structures, it also represents a data management system designed to assist in a broad array of metabolite research and metabolite identification by providing public access to its repository of current and comprehensive MS/MS metabolite data. An annotated list of known metabolites and their mass, chemical formula, and structure are available on the METLIN website. Each metabolite is conveniently linked to outside resources such as the the Kyoto Encyclopedia of Genes and Genomes (KEGG) for further reference and inquiry. MS/MS data is also available on many of the metabolites. The list is expanding continuously as more metabolite information is being deposited and discovered. [from http://metlin.scripps.edu/] Metlin is a component of the MAGGIE Project. MAGGIE is funded by the DOE Genomics: GTL and is an acronym for "Molecular Assemblies, Genes, and Genomics Integrated Efficiently."

  3. Qualitative identification of rodenticide anticoagulants by LC-MS/MS.

    PubMed

    Middleberg, Robert A; Homan, Joseph

    2012-01-01

    Rodenticide anticoagulants are used in the control of rodent populations. In addition to accidental ingestions in humans, such agents have also been used for homicidal and suicidal purposes. There are two major groups of rodenticide anticoagulants - hydroxycoumarins and indanediones. Before the advent of LC-MS/MS, analysis for such agents was relegated to such techniques as TLC and HPLC with nonspecific modes of detection. LC-MS/MS has been used to determine any given number of rodenticide anticoagulants in animal tissues, foods, plasma, etc. Use of this technique allows for the simultaneous identification of individual compounds within both classes of rodenticide anticoagulants. The LC-MS/MS method presented allows for simultaneous qualitative identification of brodifacoum, bromadiolone, chlorphacinone, dicumarol, difenacoum, diphacinone, and warfarin in blood, serum, and plasma using ESI in the negative mode. Two transitions are monitored for each analyte after a simple sample preparation. Chromatographic separation is accomplished using a gradient of ammonium hydroxide in water and ammonium hydroxide in methanol. Chloro-warfarin is used as internal standard.

  4. Finding of pesticides in fashionable fruit juices by LC-MS/MS and GC-MS/MS.

    PubMed

    Tran, Kevin; Eide, David; Nickols, Susan M; Cromer, Michele R; Sabaa-Srur, Armando; Smith, Robert E

    2012-10-15

    Products labelled as containing extracts from two mushrooms (cordyceps plus reishi) and the juices from açaí, goji, mangosteen, noni, pomegranate, and sea buckthorn have been analysed for 174 different pesticides, using the validated QuEChERS method for sample preparation and electrospray LC-MS/MS in the positive ion mode for analysis. Pesticides were found in 10 of the 21 samples analysed. Most pesticides found were below the tolerance levels (1-6 μg/g, depending on the pesticide), but some were not. This included boscalid, dimethomorph, iprovalicarb, pyridaben, pyrimethanil, and imazalil, for which there is no tolerance reported or zero tolerance in any fruit. However, genuine açaí that was harvested in the state of Pará and lyophilised in Rio de Janeiro had no detectable pesticides, when analysed by both LC-MS/MS and GC-MS/MS, which can detect 213 more pesticides and industrial chemicals. Likewise no pesticides were found in one sample each of cordyceps plus reishi, sea buckthorn and noni.

  5. ExMS: Data Analysis for HX-MS Experiments

    NASA Astrophysics Data System (ADS)

    Kan, Zhong-Yuan; Mayne, Leland; Sevugan Chetty, Palaniappan; Englander, S. Walter

    2011-11-01

    A previous paper considered the problems that presently limit the hydrogen exchange - mass spectrometry (HX-MS) method for studying the biophysical and functional properties of proteins. Many of these problems can be overcome by obtaining and analyzing hundreds of sequentially overlapping peptide fragments that cover the protein many times over (Mayne et al. J. Am. Soc. Mass Spectrom. 2011: 10.1007/s13361-011-0235-4). This paper describes a computer program called ExMS that furthers this advance by making it possible to efficiently process crowded mass spectra and definitively identify and characterize these many peptide fragments. ExMS automatically scans through high resolution MS data to find the individual isotopic peaks and isotopic envelopes of a list of peptides previously identified by MS/MS. It performs a number of tests to ensure correct identification in spite of peptide overlap in both chromatographic and mass spectrometric dimensions and possible multi-modal envelopes due to static or dynamic structural heterogeneity or HX EX1 behavior. The program can automatically process data from many sequential HX time points with no operator intervention at the rate of ~2 sec per peptide per HX time point using desktop computer equipment, but it also provides for rapid manual checking and decision when ambiguity exists. Additional subroutines can provide a step by step report of performance at each test along the way and parameter adjustment, deconvolute isotopic envelopes, and plot the time course of single and multi-modal H-D exchange. The program will be available on an open source basis at: http://HX2.med.upenn.edu/download.html

  6. Modeling Contaminants in AP-MS/MS Experiments

    PubMed Central

    Lavallée-Adam, Mathieu; Cloutier, Philippe; Coulombe, Benoit; Blanchette, Mathieu

    2015-01-01

    Identification of protein–protein interactions (PPI) by affinity purification (AP) coupled with tandem mass spectrometry (AP-MS/MS) produces large data sets with high rates of false positives. This is in part because of contamination at the AP level (due to gel contamination, nonspecific binding to the TAP columns in the context of tandem affinity purification, insufficient purification, etc.). In this paper, we introduce a Bayesian approach to identify false-positive PPIs involving contaminants in AP-MS/MS experiments. Specifically, we propose a confidence assessment algorithm (called Decontaminator) that builds a model of contaminants using a small number of representative control experiments. It then uses this model to determine whether the Mascot score of a putative prey is significantly larger than what was observed in control experiments and assigns it a p-value and a false discovery rate. We show that our method identifies contaminants better than previously used approaches and results in a set of PPIs with a larger overlap with databases of known PPIs. Our approach will thus allow improved accuracy in PPI identification while reducing the number of control experiments required. PMID:21117706

  7. MS-MS Approaches for the Analysis of Environmental Pollutants

    EPA Science Inventory

    Concern about the environment and the start of environmental analysis coincided with the rise of gas chromatography-mass spectrometry (GC-MS). The United States Environmental Protection Agency (U.S. EPA) was founded in 1970, and as the need for techniques to analyze environmental...

  8. Disposable chromatography for a high-throughput nano-ESI/MS and nano-ESI/MS-MS platform.

    PubMed

    Williams, Jason G; Tomer, Kenneth B

    2004-09-01

    High-throughput proteomics has typically relied on protein identification based on MALDI-MS peptide maps of proteolytic digests of 2D-gel-separated proteins. This technique, however, requires significant sequence coverage in order to achieve a high level of confidence in the identification. Tandem MS data have the advantage of requiring fewer peptides (2) for high confidence identification, assuming adequate MS/MS sequence coverage. MALDI-MS/MS techniques are becoming available, but can still be problematic because of the difficulty of inducing fragment ions of a singly charged parent ion. Electrospray ionization, however, has the advantage of generating multiply charged species that are more readily fragmented during MS/MS analysis. Two electrospray/tandem mass spectrometry-based approaches, nanovial-ESI-MS/MS and LC-MS/MS, are used for high throughput proteomics, but much less often than MALDI-MS and peptide mass fingerprinting. Nanovial introduction entails extensive manual manipulation and often shows significant chemical background from the in-gel digest. LC-MS has the advantages that the chemical background can be removed prior to analysis and the analytes are concentrated during the separation, resulting in more abundant analyte signals. On the other hand, LC-MS can often be time intensive. Here, we report the incorporation of on-line sample clean-up and analyte concentration with a high-throughput, chip-based, robotic nano-ESI-MS platform for proteomics studies.

  9. 10 years of MS instrumental developments--impact on LC-MS/MS in clinical chemistry.

    PubMed

    Himmelsbach, Markus

    2012-02-01

    The combination of liquid chromatography and mass spectrometry (LC-MS) is a powerful and indispensable analytical tool that is widely applied in many areas of chemistry, medicine, pharmaceutics and biochemistry. In this review recent MS instrumental developments are presented as part of a special issue covering various aspects of liquid chromatography tandem mass spectrometry (LC-MS/MS) in clinical chemistry. Improvements, new inventions as well as new combinations in ion source technology are described focusing on dual or multimode sources and atmospheric pressure photoionization (APPI). Increasing demands regarding sensitivity, accuracy, resolution and both quantitation and identification guarantee on-going improvements in mass analyzer technology. This paper discusses new hybrid MS instruments that can perform novel scan modes as well as high-resolution mass spectrometers (HRMS) that finally seem to be able to overcome, or at least significantly reduce, their weaknesses in quantitative applications. Ion mobility-mass spectrometry (IMMS) itself is not an invention of the last 10 years, but a lot of progress was made within the last decade that reveals the potential benefits of this combination. This is clearly reflected by the increased number of commercially available instruments and the various designs of IMMS are covered in detail in this review. Selected applications for all these instrumental developments are given focusing on the perspective of clinical chemistry.

  10. Massachusetts Small MS4 General Permit | Stormwater ...

    EPA Pesticide Factsheets

    2017-02-21

    The 2016 Massachusetts Small MS4 General Permit was signed April 4, 2016 and will become effective July 1, 2017. The final permit reflects modifications to the 2014 draft small MS4 general permit released for comment on September 30, 2014 and replaces the 2003 small MS4 general permit for MS4 operators within the Commonwealth of Massachusetts.

  11. CE-microreactor-CE-MS/MS for protein analysis

    PubMed Central

    Schoenherr, Regine M.; Ye, Mingliang; Vannatta, Michael

    2008-01-01

    We present a proof-of-principle for a fully automated bottom-up approach to protein characterization. Proteins are first separated by capillary electrophoresis. A pepsin microreactor is incorporated into the distal end of this capillary. Peptides formed in the reactor are transferred to a second capillary, where they are separated by capillary electrophoresis and characterized by mass spectrometry. While peptides generated from one digestion are being separated in the second capillary, the next protein fraction undergoes digestion in the microreactor. The migration time in the first dimension capillary is characteristic of the protein while migration time in the second dimension is characteristic of the peptide. Spot capacity for the two-dimensional separation is 590. A MS/MS analysis of a mixture of cytochrome C and myoglobin generated Mascot MOWSE scores of 107 for cytochrome C and 58 for myoglobin. The sequence coverages were 48% and 22%, respectively. PMID:17295444

  12. Determination of drugs in hair using GC/MS/MS.

    PubMed

    Uhl, M

    1997-01-17

    An important task for the forensic toxicologist and expert witness is the detection of the noxa in biological matrices. Because of this, the identification and quantification of residues of illegal drugs in human hair is still of growing interest. Utilizing the advantages of GC/MS/MS testing human hair is performed for most common drugs of abuse like heroin and other opioides, cocaine, cannabis and amphetamine derivatives. Analyzing hair specimens for substances that present a toxicological risk is another challenge. Several quality control parameters must be observed to avoid false positive or false negative results and to gain additional information. Blank sample, blank hair as well as the combined wash extracts are tested for the presence of the relevant compounds within every series. Careful evaluation of the findings can provide an approximate measure of the intensity of drug use in the majority of cases.

  13. Determination of paraquat in vegetables using HPLC-MS-MS.

    PubMed

    Zou, Tingting; He, Pingli; Cao, Jingjing; Li, Zhen

    2015-02-01

    A simple, sensitive, reliable and economical method was developed for the determination of paraquat (a widely used herbicide) in four edible vegetables (cabbage, lettuce, spinach and Chinese cabbage) using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS). The samples were extracted with water under sonication and cleaned up by weak cation exchange solid-phase extraction. Chromatographic separation of paraquat was achieved on a hydrophilic interaction liquid chromatography column (2.1 × 100 mm, 3 µm) with a gradient program using 10 mM ammonium acetate in 0.1% formic acid and acetonitrile as mobile phase. The low salt concentration used in the eluting buffer ensured extended LC-MS analysis of paraquat in different matrices without the necessity of frequent source cleaning. The validity of the developed method was evaluated by spiking paraquat in four edible vegetables at 50 and 500 ng g(-1). Recovery ranged from 43.6 to 73.5%. The limit of detection is 0.94 ng g(-1). With the developed method, the kinetic of paraquat entering plant tissue was also evaluated.

  14. Quantitative acylcarnitine determination by UHPLC-MS/MS--Going beyond tandem MS acylcarnitine "profiles".

    PubMed

    Minkler, Paul E; Stoll, Maria S K; Ingalls, Stephen T; Kerner, Janos; Hoppel, Charles L

    2015-12-01

    Tandem MS "profiling" of acylcarnitines and amino acids was conceived as a first-tier screening method, and its application to expanded newborn screening has been enormously successful. However, unlike amino acid screening (which uses amino acid analysis as its second-tier validation of screening results), acylcarnitine "profiling" also assumed the role of second-tier validation, due to the lack of a generally accepted second-tier acylcarnitine determination method. In this report, we present results from the application of our validated UHPLC-MS/MS second-tier method for the quantification of total carnitine, free carnitine, butyrobetaine, and acylcarnitines to patient samples with known diagnoses: malonic acidemia, short-chain acyl-CoA dehydrogenase deficiency (SCADD) or isobutyryl-CoA dehydrogenase deficiency (IBD), 3-methyl-crotonyl carboxylase deficiency (3-MCC) or ß-ketothiolase deficiency (BKT), and methylmalonic acidemia (MMA). We demonstrate the assay's ability to separate constitutional isomers and diastereomeric acylcarnitines and generate values with a high level of accuracy and precision. These capabilities are unavailable when using tandem MS "profiles". We also show examples of research interest, where separation of acylcarnitine species and accurate and precise acylcarnitine quantification is necessary.

  15. PTR-MS in enology

    NASA Astrophysics Data System (ADS)

    Spitaler, Renate; Araghipour, Nooshin; Mikoviny, Tomas; Wisthaler, Armin; Via, Josef Dalla; Märk, Tilmann D.

    2007-10-01

    The present communication deals with the improvement of proton transfer reaction mass spectrometry (PTR-MS) wine headspace analyses. In contrast to previous PTR-MS investigations of wine, where wine headspace was ionized by protonated ethanol clusters, the headspace was diluted by a factor of 1:40 with N2 and ionized by H3O+ ions. This method is better suited for routine applications than the previously reported method since it is simpler, faster, and the mass spectra obtained are less complex. A test wine was mixed with ethanol and with water to yield ethanol contents ranging from 10 to 15% (v/v) and these mixtures were analyzed to assess whether any quantitative differences in the composition of volatiles were detectable. The data showed no impact of the ethanol content on the wine headspace composition. The new method was applied to eight different wine samples produced from two different grape varieties: Pinot Noir and Cabernet Sauvignon. Each variety was grown in two different locations in South Tyrol (Northern Italy) and harvested at two different dates. Quantitative (but not qualitative) differences in PTR-MS spectra between the two wine varieties were observed. Using principal component analysis of selected m/z signals differentiation between Pinot Noir and Cabernet Sauvignon samples was achievable.

  16. 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.

  17. 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...

  18. Dealing with MS in Your Important Relationships

    MedlinePlus

    ... Addressing the Challenges of MS Webinar & Telelearning Program Momentum Magazine Educational Videos Live Fully, Live Well Knowledge ... and access resources . Additional resources The Friend Zone - Momentum article MS in Focus Tips for People with ...

  19. New Help for MS Patients

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Mark VII MicroClimate Medical Personal Cooling system enables multiple sclerosis' victims, as well as cerebral palsy, spinabifida patients and others to lower their body temperatures. Although this is not a cure, cooling can produce a dramatic improvement in symptoms. The Multiple Sclerosis Association of America has placed cool suits in MS research care centers. This technology originated in the need for cooling systems in spa@esuits. "Cool Suits" are now used by hazardous materials workers, armored vehicle crews, firefighters and crop dusters. A surgical personal cooling system has also been developed for medical personnel working in hot operating room environments.

  20. Biomarker discovery by CE-MS enables sequence analysis via MS/MS with platform-independent separation.

    PubMed

    Zürbig, Petra; Renfrow, Matthew B; Schiffer, Eric; Novak, Jan; Walden, Michael; Wittke, Stefan; Just, Ingo; Pelzing, Matthias; Neusüss, Christian; Theodorescu, Dan; Root, Karen E; Ross, Mark M; Mischak, Harald

    2006-06-01

    CE-MS is a successful proteomic platform for the definition of biomarkers in different body fluids. Besides the biomarker defining experimental parameters, CE migration time and molecular weight, especially biomarker's sequence identity is an indispensable cornerstone for deeper insights into the pathophysiological pathways of diseases or for made-to-measure therapeutic drug design. Therefore, this report presents a detailed discussion of different peptide sequencing platforms consisting of high performance separation method either coupled on-line or off-line to different MS/MS devices, such as MALDI-TOF-TOF, ESI-IT, ESI-QTOF and Fourier transform ion cyclotron resonance, for sequencing indicative peptides. This comparison demonstrates the unique feature of CE-MS technology to serve as a reliable basis for the assignment of peptide sequence data obtained using different separation MS/MS methods to the biomarker defining parameters, CE migration time and molecular weight. Discovery of potential biomarkers by CE-MS enables sequence analysis via MS/MS with platform-independent sample separation. This is due to the fact that the number of basic and neutral polar amino acids of biomarkers sequences distinctly correlates with their CE-MS migration time/molecular weight coordinates. This uniqueness facilitates the independent entry of different sequencing platforms for peptide sequencing of CE-MS-defined biomarkers from highly complex mixtures.

  1. MOMA GC-MS coupling

    NASA Astrophysics Data System (ADS)

    Buch, A.; Pinnick, V. T.; Grand, N.; Szopa, C.; Danell, R.; Lustrement, B.; Freissinet, C.; van Amerom, F. H.; Raulin, F.; Glavin, D. P.; Stalport, F.; Coll, P. J.; Arevalo, R. D.; Brinckerhoff, W. B.; Goesmann, F.; Mahaffy, P. R.

    2013-12-01

    The joint ESA-Roscosmos Exo-Mars-2018 rover mission seeks the signs of past or present life on Mars. The Mars Organic Molecule Analyzer (MOMA) aboard the ExoMars rover will be a key analytical tool in providing chemical (molecular) information from the solid samples, with particular focus on the characterization of organic content. Central to MOMA instrumentation is a gas chromatograph-mass spectrometer (GC-MS) which provides the unique ability to characterize a broad range of compounds allowing chemical analyses of volatile and non-volatile species. The Gas chromatograph and the oven have been built at LATMOS/LISA (France) and at MPS (Germany) respectively whereas the mass spectrometer has been built at the NASA Goddard Space Flight Center (USA). Both instruments have been tested separately first and have been coupled in order to test the efficiency of the future MOMA GC-MS instrument. The main objective of the second step has been to test the quantitative response of both instruments while they are coupled and to characterize the combined instrument detection limit for several compounds. A final experiment has been done in order to test the feasibility of the separation and detection of a mixture contained in a soil sample introduced in the MOMA oven.

  2. Treatment optimization in MS: Canadian MS Working Group updated recommendations.

    PubMed

    Freedman, Mark S; Selchen, Daniel; Arnold, Douglas L; Prat, Alexandre; Banwell, Brenda; Yeung, Michael; Morgenthau, David; Lapierre, Yves

    2013-05-01

    The Canadian Multiple Sclerosis Working Group (CMSWG) developed practical recommendations in 2004 to assist clinicians in optimizing the use of disease-modifying therapies (DMT) in patients with relapsing multiple sclerosis. The CMSWG convened to review how disease activity is assessed, propose a more current approach for assessing suboptimal response, and to suggest a scheme for switching or escalating treatment. Practical criteria for relapses, Expanded Disability Status Scale (EDSS) progression and MRI were developed to classify the clinical level of concern as Low, Medium and High. The group concluded that a change in treatment may be considered in any RRMS patient if there is a high level of concern in any one domain (relapses, progression or MRI), a medium level of concern in any two domains, or a low level of concern in all three domains. These recommendations for assessing treatment response should assist clinicians in making more rational choices in their management of relapsing MS patients.

  3. The immortality of Ms Jones.

    PubMed

    Gallagher, Timothy

    2014-07-01

    When I began my medical student clinical rotations, I quickly became overwhelmed by feelings of inadequacy. While the doctors around me conjured appropriate diagnoses and treatment approaches, I fumbled with the only tools I possessed: my time and a smile. It was only when I met the patient Ms Jones that I came to understand the potential impact of these simple tools. My encouragement became part of her recovery process. She gave me the confidence to construct this ability of comforting patients into a small platform of confidence from which I could safely venture to educate patients or suggest treatments to residents. It could be something that I could reliably fall back on in times of doubt and something I could pass along to other people I met.

  4. The Immortality of Ms Jones

    PubMed Central

    Gallagher, Timothy

    2014-01-01

    When I began my medical student clinical rotations, I quickly became overwhelmed by feelings of inadequacy. While the doctors around me conjured appropriate diagnoses and treatment approaches, I fumbled with the only tools I possessed: my time and a smile. It was only when I met the patient Ms Jones that I came to understand the potential impact of these simple tools. My encouragement became part of her recovery process. She gave me the confidence to construct this ability of comforting patients into a small platform of confidence from which I could safely venture to educate patients or suggest treatments to residents. It could be something that I could reliably fall back on in times of doubt and something I could pass along to other people I met. PMID:25024247

  5. PTR-MS and GC-MS Analyses of Sesquiterpenes

    NASA Astrophysics Data System (ADS)

    Rasmussen, R. A.; Geron, C.; Goldstein, A. H.; Holzinger, R.; Lee, A.

    2003-12-01

    Terpene hydrocarbons are ubiquitous compounds in the atmosphere. Frits Went, in 1960 suggested that the volatile organic emissions from plants especially the monoterpenes were responsible for the formation of the atmosphere's `blue haze'. Surveys of plant emissions using a Proton Transfer Reaction - Mass Spectrometer (PTR-MS) have shown that many species emit sesquiterpenes (Ssqt's) independent of emitting monoterpenes or isoprene. It is possible they are a comparable source of the organic micro-aerosols responsible for scattering the blue end of the spectrum, i.e. `blue haze' in addition to the monoterpenes as they have more rapid and complete reactions with ozone resulting in particles. Ambient concentrations of the terpenic hydrocarbons are site dependent, but are typically very low from a few to 1000 pptCv, except for isoprene which has summer mid-day median levels of 3 to 6 ppbCv. The sesquiterpenes are very difficult to measure in the atmosphere by conventional means but cubebene, copaene, bourbonene and alpha- and beta-caryophyllene are common foliage emissions. Direct measurements of isoprene, monoterpenes and sesquiterpenes over plant foliages with a PTR-MS were compared with captive samples of the air from the same plant foliages collected in Summa canisters. None of the biogenic organic emissions stored in the Summa canisters showed any significant losses due to wall effects. Neither did we observe that any of the processing steps were responsible for losses or internal molecular rearrangements. The reason for the stability and 100% recovery of these C5 to C15 olefinic compounds at room temperature is believed to be due to the water layer formed on the electropolished stainless steel walls of the canister under pressure at 30 psig. Ozone added to the test systems was observed to have an immediate effect on the sesquiterpenes at ambient levels. Measurements made this past summer at the Duke and Blodgett Research Forests again confirm that the ambient

  6. Profiling cytosine oxidation in DNA by LC-MS/MS.

    PubMed

    Samson-Thibault, Francois; Madugundu, Guru S; Gao, Shanshan; Cadet, Jean; Wagner, J Richard

    2012-09-17

    Spontaneous and oxidant-induced damage to cytosine is probably the main cause of CG to TA transition mutations in mammalian genomes. The reaction of hydroxyl radical (·OH) and one-electron oxidants with cytosine derivatives produces numerous oxidation products, which have been identified in large part by model studies with monomers and short oligonucleotides. Here, we developed an analytical method based on LC-MS/MS to detect 10 oxidized bases in DNA, including 5 oxidation products of cytosine. The utility of this method is demonstrated by the measurement of base damage in isolated calf thymus DNA exposed to ionizing radiation in aerated aqueous solutions (0-200 Gy) and to well-known Fenton-like reactions (Fe(2+) or Cu(+) with H(2)O(2) and ascorbate). The following cytosine modifications were quantified as modified 2'-deoxyribonucleosides upon exposure of DNA to ionizing radiation in aqueous aerated solution: 5-hydroxyhydantoin (Hyd-Ura) > 5-hydroxyuracil (5-OHUra) > 5-hydroxycytosine (5-OHCyt) > 5,6-dihydroxy-5,6-dihydrouracil (Ura-Gly) > 1-carbamoyl-4,5-dihydroxy-2-oxoimidazolidine (Imid-Cyt). The total yield of cytosine oxidation products was comparable to that of thymine oxidation products (5,6-dihydroxy-5,6-dihydrothymine (Thy-Gly), 5-hydroxy-5-methylhydantotin (Hyd-Thy), 5-(hydroxymethyl)uracil (5-HmUra), and 5-formyluracil (5-ForUra)) as well as the yield of 8-oxo-7,8-dihydroguanine (8-oxoGua). The major oxidation product of cytosine in DNA was Hyd-Ura. In contrast, the formation of Imid-Cyt was a minor pathway of DNA damage, although it is the major product arising from irradiation of the monomers, cytosine, and 2'-deoxycytidine. The reaction of Fenton-like reagents with DNA gave a different distribution of cytosine derived products compared to ionizing radiation, which likely reflects the reaction of metal ions with intermediate peroxyl radicals or hydroperoxides. The analysis of the main cytosine oxidation products will help elucidate the complex

  7. LC-MS systems for quantitative bioanalysis.

    PubMed

    van Dongen, William D; Niessen, Wilfried M A

    2012-10-01

    LC-MS has become the method-of-choice in small-molecule drug bioanalysis (molecular mass <800 Da) and is also increasingly being applied as an alternative to ligand-binding assays for the bioanalytical determination of biopharmaceuticals. Triple quadrupole MS is the established bioanalytical technique due to its unpreceded selectivity and sensitivity, but high-resolution accurate-mass MS is recently gaining ground due to its ability to provide simultaneous quantitative and qualitative analysis of drugs and their metabolites. This article discusses current trends in the field of bioanalytical LC-MS (until September 2012), and provides an overview of currently available commercial triple quadrupole MS and high-resolution LC-MS instruments as applied for the bioanalysis of small-molecule and biopharmaceutical drugs.

  8. LC-MS/MS in the Clinical Laboratory – Where to From Here?

    PubMed Central

    Grebe, Stefan KG; Singh, Ravinder J

    2011-01-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in clinical laboratories during the last 10–15 years. It offers analytical specificity superior to that of immunoassays or conventional high performance/pressure liquid chromatography (HPLC) for low molecular weight analytes and has higher throughput than gas chromatography-mass spectrometry (GC-MS). Drug/Toxicology and Biochemical Genetics/Newborn Screening laboratories were at the vanguard of clinical LC-MS/MS use, but have been eclipsed by Endocrine laboratories. In USA reference/referral laboratories, most steroids and biogenic amines are now assayed by LC-MS/MS, and the technology has started to penetrate into smaller laboratories. Assays for mineralo- and gluco-corticoids and their precursors, sex steroids, metanephrines and 25-hydroxy vitamin D highlight the advantages of LC-MS/MS. However, several limitations of LC-MS/MS have become apparent, centring on the interacting triangle of sensitivity – specificity – throughput. While sample throughput is higher than for conventional HPLC or GC-MS, it lags behind automated immunoassays. Techniques which improve throughput include direct sample injection, LC-multiplexing and samplemultiplexing. Measures to improve specificity and sensitivity include sample clean-up and optimising chromatography to avoid interferences and ion suppression due to sample-matrix components. Next generation instrumentation may offer additional benefits. The next challenge for clinical LC-MS/MS is peptide/protein analysis. The quest for multi-biomarker profiles for various diseases has largely failed, but targeted peptide and protein testing by LC-MS/MS, directed at analytical and clinical questions that need to be answered, is proving highly successful. We anticipate that this will result in similar growth of clinical protein/peptide LC-MS/MS as has been seen for low molecular weight applications. PMID:21451775

  9. A Comparison of nLC-ESI-MS/MS and nLC-MALDI-MS/MS for GeLC-based Protein Identification and iTRAQ-based Shotgun Quantitative Proteomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of nLC-ESI-MS/MS in shotgun proteomics experiments and GeLC-MS/MS analysis is well accepted and routinely available in most proteomics laboratories. However, the same cannot be said for nLC-MALDI MS/MS, which has yet to experience such widespread acceptance despite the fact that the MALDI t...

  10. Repeated exposure of goldfish (Carassius auratus) to tricaine methanesulfonate (MS-222).

    PubMed

    Posner, Lysa Pam; Scott, Gregory N; Law, J McHugh

    2013-06-01

    Goldfish that have been repeatedly exposed to tricaine methanesulfonate (MS-222) require greater concentration of the drug to attain equivalent planes of anesthesia, but the mechanism for this increased anesthetic need is unknown. Minimum anesthetic concentration (MAC) is a commonly used method with which to compare anesthetics. It was hypothesized that fish exposed to MS-222 daily would have an increased MAC. It was also hypothesized that fish exposed daily to MS-222 would develop histomorphologic changes to their gills to explain the increasing demand. Forty-nine Serasa comet goldfish were enrolled and were divided into three populations (n = 15, n = 15, and n = 19). In trial 1, using an up-down method, MAC was determined daily after 4 min of exposure to MS-222 for which the starting concentration was 160 mg/L. In trial 2, MAC was determined following 2 min of exposure to MS-222 for which the starting concentration was 260 mg/L. In trial 3, four naive fish were euthanatized and gills collected for histology and electron microscopy (EM). The remaining fish were exposed to MS-222 daily for 4 wk. Four fish were euthanatized and their gills submitted for similar examination at 2 wk and 4 wk. MAC for fish exposed to MS-222 for 4 min increased from 120 to 160 mg/L. The regression line had a slope of 1.51 +/- 0.26 (R2 = 0.65; P < 0.0001). MAC for fish exposed to MS-222 for 2 min increased from 210 pmm to 220 mg/L; the regression line had a slope of 0.52 +/- 0.38 (R2 = 0.12; P = 0.2). Histologic and EM examination of gills did not show morphologic changes indicative of a reaction to MS-222. Goldfish in this study had an increased requirement for MS-222 following daily exposure for 4 min but not following daily exposure for 2 min at a higher concentration. The cause of this increased anesthetic need is not related to morphologic changes to the gills.

  11. LC-MS/MS analysis of steroids in the clinical laboratory.

    PubMed

    Keevil, Brian G

    2016-09-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool that is changing the way we analyse steroids in the clinical laboratory. It is already opening up the field of steroid analysis in endocrinology and is providing new applications for individual steroids and panels of steroids in different clinical conditions. LC-MS/MS is now well-accepted technology and is increasingly being used to replace problematic immunoassay methods because of greater sensitivity and specificity. Improved sample preparation, modern chromatography methods, and sensitive, faster scanning mass spectrometers have all played a role in improving LC-MS/MS. LC-MS/MS is also playing a key role in improving the quality of assays through the development of reference measurement procedures, characterisation of reference materials and multi-site calibration programmes. There is increasing interest in multiplexing steroid assays into panels of diagnostic tests to aid and improve the diagnosis and monitoring of disease.

  12. [Method for determination of histamine in food by LC-MS/MS].

    PubMed

    Ohtsubo, Yoshito; Kurooka, Hiroyuki; Tada, Hisae; Manabe, Noboru

    2014-01-01

    In Japan, a criterion value of histamine residue in food is not clearly defined and there is no official test method. We examined histamine in fish and fish products according to the food sanitation test guideline (fluorescence derivatization of histamine with dansyl chloride and quantification by LC-FL: the LC-FL method). Positive samples were confirmed by determining dansylated histamine using our developed LC-MS/MS procedure (the LC-MS/MS method) when histamine was detected. Validation was earried out according to the validation test guideline using fresh fish. Recovery tests of histamine from fresh fish spiked at the level of 20 ppm were carried out. The limit of quantification was 5 ppm. The results confirmed that our LC-MS/MS method is applicable for the inspection of fish and fish products. This LC-MS/MS method has a lower false-positive ratio and a higher selectivity than the LC-FL method.

  13. Gadofosveset: MS 325, MS 32520, Vasovist, ZK 236018.

    PubMed

    2004-01-01

    Gadofosveset [MS 325, MS 32520, Vasovist, ZK 236018], a gadolinium-based chelate, is an injectable angiography imaging agent for use in magnetic resonance imaging (MRI) scans. The agent is being developed by EPIX Medical (formerly Metasyn) for diagnostic imaging of blood vessels of the cardiovascular system. Gadofosveset has potential as an alternative to the range of x-ray, invasive, catheter-based angiograms and thallium stress tests currently used in the diagnosis of coronary artery disease. The agent may also have applications in the diagnosis of peripheral vascular disease, thrombosis and breast cancer. Unlike conventional MRI contrast agents, gadofosveset binds to serum albumin in the blood and moves with the blood through the arteries and veins for an extended period of time before being excreted by the kidneys. The MRI with gadofosveset allows 3D images of the whole body to be accessed in one imaging session. Moreover, it makes it possible to view vessel structures.EPIX Medical has acquired an exclusive licence from the Massachusetts General Hospital to a certain technology, including patents and patent applications, that relates to the company's product candidates such as gadofosveset.EPIX Medical, Mallinckrodt (Tyco International) and Schering AG signed several agreements to develop, manufacture and market gadofosveset (formerly known as Mallinckrodt's AngioMARK). Initially, in June 2000 Schering AG acquired worldwide exclusive rights (except for Japan) from EPIX Medical to develop and market gadofosveset. Under the terms of the agreement, EPIX Medical is responsible for the completion of clinical trials and filing for approval in the US, while Schering AG undertakes responsibility for clinical investigation of gadofosveset outside the US. Mallinckrodt is responsible and will undertake a long-term supply contract for gadofosveset for clinical development and sales. Schering's subsidiary Berlex will market the product in the US after the approval via its

  14. LC-MS/MS Method for Serum Creatinine: Comparison with Enzymatic Method and Jaffe Method

    PubMed Central

    Li, Shuijun; Liu, Gangyi; Jia, Jingying; Zhang, Menqi; Zhang, Haichen; Yu, Chen

    2015-01-01

    Accurate quantification of creatinine (Cre) is important to estimate glomerular filtration rate (GFR). Differences among various methods of Cre quantification were previously noted. This study aims to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for serum Cre and compare this method with clinical routine methods. LC-MS/MS analysis was performed on API 4000 triple quadrupole mass spectrometer coupled with an Agilent 1200 liquid chromatography system. After adding isotope-labeled Cre-d3 as internal standard, serum samples were prepared via a one-step protein precipitation with methanol. The LC-MS/MS method was compared with frequently used enzymatic method and Jaffe method. This developed method, with a total run time of 3 min, had a lower limit of quantification of 4.4 μmol/L, a total imprecision of 1.15%–3.84%, and an average bias of 1.06%. No significant matrix effect, carryover, and interference were observed for the LC-MS/MS method. The reference intervals of serum Cre measured by LC-MS/MS assay were 41–79 μmol/L for adult women, and 46–101 μmol/L for adult men. Using LC-MS/MS as a reference, the enzymatic method showed an average bias of -2.1% and the Jaffe method showed a substantial average bias of 11.7%. Compared with the LC-MS/MS method, significant negative bias was observed for the enzymatic and Jaffe methods in hemolytic and lipimic samples. We developed a simple, specific, and accurate LC-MS/MS method to analyze serum Cre. Discordance existed among different methods. PMID:26207996

  15. Efficient Modeling of MS/MS Data for Metabolic Flux Analysis.

    PubMed

    Tepper, Naama; Shlomi, Tomer

    2015-01-01

    Metabolic flux analysis (MFA) is a widely used method for quantifying intracellular metabolic fluxes. It works by feeding cells with isotopic labeled nutrients, measuring metabolite isotopic labeling, and computationally interpreting the measured labeling data to estimate flux. Tandem mass-spectrometry (MS/MS) has been shown to be useful for MFA, providing positional isotopic labeling data. Specifically, MS/MS enables the measurement of a metabolite tandem mass-isotopomer distribution, representing the abundance in which certain parent and product fragments of a metabolite have different number of labeled atoms. However, a major limitation in using MFA with MS/MS data is the lack of a computationally efficient method for simulating such isotopic labeling data. Here, we describe the tandemer approach for efficiently computing metabolite tandem mass-isotopomer distributions in a metabolic network, given an estimation of metabolic fluxes. This approach can be used by MFA to find optimal metabolic fluxes, whose induced metabolite labeling patterns match tandem mass-isotopomer distributions measured by MS/MS. The tandemer approach is applied to simulate MS/MS data in a small-scale metabolic network model of mammalian methionine metabolism and in a large-scale metabolic network model of E. coli. It is shown to significantly improve the running time by between two to three orders of magnitude compared to the state-of-the-art, cumomers approach. We expect the tandemer approach to promote broader usage of MS/MS technology in metabolic flux analysis.

  16. EPA CRL MS014: Analysis of Aldicarb, Bromadiolone, Carbofuran, Oxamyl and Methomyl in Water by Multiple Reaction Monitoring Liquid Chromatography / Tandem Mass Spectrometry (LC/MS/MS)

    EPA Pesticide Factsheets

    Method MS014 describes procedures for solvent extraction of aldicarb, bromadiolone, carbofuran, oxamyl and methomyl from water samples, followed by analysis using liquid chromatography tandem mass spectrometry (LC-MS-MS).

  17. EMS Student Handbook.

    ERIC Educational Resources Information Center

    Ogle, Patrick

    This student guide is one of a series of self-contained materials for students enrolled in an emergency medical services (EMS) training program. Discussed in the individual sections of the guide are the following topics: the purpose and history of EMS professionals; EMS training, certification and examinations (national and state certification and…

  18. Automated precursor ion exclusion during LC-MS/MS data acquisition for optimal ion identification.

    PubMed

    Zhang, Zhongqi

    2012-08-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is widely used for characterizing multiple samples of complex mixtures with similar compositions. This article addresses a data acquisition strategy for collecting a maximal number of unique, high-quality MS/MS during LC-MS/MS analysis of multiple samples. Based on the concept that a component only needs to be identified once when analyzing multiple samples with similar compositions, an automated intersample data-dependent acquisition strategy was developed. The strategy is based on precursor ion exclusion (PIE) and is implemented in MassAnalyzer in an automated fashion for Thermo Scientific (San Jose, CA, USA) mass spectrometers. In this method, MassAnalyzer submits one sample at a time to the sample queue. After data acquisition of each sample, MassAnalyzer automatically analyzes the data to generate a PIE list based on the MS/MS precursor ions, merges this list with the list generated from previous runs, adds the list to the MS method file, and submits the next sample to the queue. The PIE list contains both m/z value and time window for each precursor ion, and is generated intelligently so that if an MS/MS is insufficient for identifying the peak of interest, it will be collected again near the top of the peak in the next run. Therefore, the strategy maximizes both quality and the number of unique MS/MS. When automated PIE was used to acquire LC-MS/MS data of an antibody tryptic digest and a soy hydrolysate sample, the number of identified ions increased by 52% and 93%, respectively, compared with data acquired without using PIE.

  19. Applications and challenges in using LC-MS/MS assays for quantitative doping analysis.

    PubMed

    Wang, Zhanliang; Lu, Jianghai; Zhang, Yinong; Tian, Ye; Yuan, Hong; Xu, Youxuan

    2016-06-01

    LC-MS/MS is useful for qualitative and quantitative analysis of 'doped' biological samples from athletes. LC-MS/MS-based assays at low-mass resolution allow fast and sensitive screening and quantification of targeted analytes that are based on preselected diagnostic precursor-product ion pairs. Whereas LC coupled with high-resolution/high-accuracy MS can be used for identification and quantification, both have advantages and challenges for routine analysis. Here, we review the literature regarding various quantification methods for measuring prohibited substances in athletes as they pertain to World Anti-Doping Agency regulations.

  20. The Neurophysiologist Perspective into MS Plasticity

    PubMed Central

    Houdayer, Elise; Comi, Giancarlo; Leocani, Letizia

    2015-01-01

    Multiple sclerosis (MS) is a frequent, highly debilitating inflammatory demyelinating disease, starting to manifest in early adulthood and presenting a wide variety of symptoms, which are often resistant to pharmacological treatments. Cortical dysfunctions have been demonstrated to be key components of MS condition, and plasticity of the corticospinal motor system is highly involved in major MS symptoms, such as fatigue, spasticity, or pain. Cortical dysfunction in MS can be studied with neurophysiological tools, such as electroencephalography (EEG) and related techniques (evoked potentials) or transcranial magnetic stimulation (TMS). These techniques are now widely used to provide essential elements of MS diagnosis and can also be used to modulate plasticity. Indeed, the recent development of non-invasive brain stimulation techniques able to induce cortical plasticity, such as repetitive TMS or transcranial direct current stimulation, has brought promising results as add-on treatments. In this review, we will focus on the use of these tools (EEG and TMS) to study plasticity in MS and on the major techniques used to modulate plasticity in MS. PMID:26388835

  1. Improved Chiral Separation of Methamphetamine Enantiomers Using CSP-LC-MS-MS.

    PubMed

    Ward, Lauren F; Enders, Jeffrey R; Bell, David S; Cramer, Hugh M; Wallace, Frank N; McIntire, Gregory L

    2016-05-01

    To determine the true enantiomeric composition of methamphetamine urine drug testing results, chiral separation of dextro (D) and levo (L) enantiomers is necessary. While enantiomeric separation of methamphetamine has traditionally been accomplished using gas chromatography-mass spectrometry (GC-MS), chiral separation of D- and L-methamphetamine by chiral stationary phase (CSP) liquid chromatography-mass spectrometry/mass spectrometry (LC-MS-MS) has proved more reliable. Chirally selective detection of methamphetamine by GC-MS is often performed using L-N-trifluoroacetyl-prolyl chloride (TPC). L-TPC, a chiral compound, is known to have impurities that can affect the chiral composition percentages of the methamphetamine sample, potentially leading to inaccurate patient results. The comparative analysis of the samples run by GC and LC methods showed preferential bias of the GC method for producing error rates, consistent with previous research, of 8-19%. The CSP-LC-MS-MS method produces percent deviation errors of <2%. Additionally, the GC method failed to produce results that were 100% D- or L-isomer even for enantiomerically pure standards. A higher rate of D- and L-methamphetamine isomer racemization is seen in samples when analyzed by GC-MS using L-TPC-derivatizing agent. This racemization is not seen when these samples are tested with CSP-LC-MS-MS. Thus, a more accurate method of enantiomeric analysis is provided by CSP-LC-MS-MS.

  2. MS/MS networking guided analysis of molecule and gene cluster families.

    PubMed

    Nguyen, Don Duy; Wu, Cheng-Hsuan; Moree, Wilna J; Lamsa, Anne; Medema, Marnix H; Zhao, Xiling; Gavilan, Ronnie G; Aparicio, Marystella; Atencio, Librada; Jackson, Chanaye; Ballesteros, Javier; Sanchez, Joel; Watrous, Jeramie D; Phelan, Vanessa V; van de Wiel, Corine; Kersten, Roland D; Mehnaz, Samina; De Mot, René; Shank, Elizabeth A; Charusanti, Pep; Nagarajan, Harish; Duggan, Brendan M; Moore, Bradley S; Bandeira, Nuno; Palsson, Bernhard Ø; Pogliano, Kit; Gutiérrez, Marcelino; Dorrestein, Pieter C

    2013-07-09

    The ability to correlate the production of specialized metabolites to the genetic capacity of the organism that produces such molecules has become an invaluable tool in aiding the discovery of biotechnologically applicable molecules. Here, we accomplish this task by matching molecular families with gene cluster families, making these correlations to 60 microbes at one time instead of connecting one molecule to one organism at a time, such as how it is traditionally done. We can correlate these families through the use of nanospray desorption electrospray ionization MS/MS, an ambient pressure MS technique, in conjunction with MS/MS networking and peptidogenomics. We matched the molecular families of peptide natural products produced by 42 bacilli and 18 pseudomonads through the generation of amino acid sequence tags from MS/MS data of specific clusters found in the MS/MS network. These sequence tags were then linked to biosynthetic gene clusters in publicly accessible genomes, providing us with the ability to link particular molecules with the genes that produced them. As an example of its use, this approach was applied to two unsequenced Pseudoalteromonas species, leading to the discovery of the gene cluster for a molecular family, the bromoalterochromides, in the previously sequenced strain P. piscicida JCM 20779(T). The approach itself is not limited to 60 related strains, because spectral networking can be readily adopted to look at molecular family-gene cluster families of hundreds or more diverse organisms in one single MS/MS network.

  3. MUSCLE: automated multi-objective evolutionary optimization of targeted LC-MS/MS analysis.

    PubMed

    Bradbury, James; Genta-Jouve, Grégory; Allwood, J William; Dunn, Warwick B; Goodacre, Royston; Knowles, Joshua D; He, Shan; Viant, Mark R

    2015-03-15

    Developing liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of (bio)chemicals is both time consuming and challenging, largely because of the large number of LC and MS instrument parameters that need to be optimized. This bottleneck significantly impedes our ability to establish new (bio)analytical methods in fields such as pharmacology, metabolomics and pesticide research. We report the development of a multi-platform, user-friendly software tool MUSCLE (multi-platform unbiased optimization of spectrometry via closed-loop experimentation) for the robust and fully automated multi-objective optimization of targeted LC-MS/MS analysis. MUSCLE shortened the analysis times and increased the analytical sensitivities of targeted metabolite analysis, which was demonstrated on two different manufacturer's LC-MS/MS instruments.

  4. EM International. Volume 1

    SciTech Connect

    Not Available

    1993-07-01

    It is the intent of EM International to describe the Office of Environmental Restoration and Waste Management`s (EM`s) various roles and responsibilities within the international community. Cooperative agreements and programs, descriptions of projects and technologies, and synopses of visits to international sites are all highlighted in this semiannual journal. Focus on EM programs in this issue is on international collaboration in vitrification projects. Technology highlights covers: in situ sealing for contaminated sites; and remote sensors for toxic pollutants. Section on profiles of countries includes: Arctic contamination by the former Soviet Union, and EM activities with Germany--cooperative arrangements.

  5. Positive and negative ion mode ESI-MS and MS/MS for studying drug-DNA complexes

    NASA Astrophysics Data System (ADS)

    Rosu, Frédéric; Pirotte, Sophie; Pauw, Edwin De; Gabelica, Valérie

    2006-07-01

    We report systematic investigation of duplex DNA complexes with minor groove binders (Hoechsts 33258 and 33342, netropsin and DAPI) and intercalators (daunomycin, doxorubicin, actinomycin D, ethidium, cryptolepine, neocryptolepine, m-Amsacrine, proflavine, ellipticine and mitoxantrone) by ESI-MS and ESI-MS/MS in the negative ion mode and in the positive ion mode. The apparent solution phase equilibrium binding constants can be determined by measuring relative intensities in the ESI-MS spectrum. While negative ion mode gives reliable results, positive ion mode gives a systematic underestimation of the binding constants and even a complete suppression of the complexes for intercalators lacking functional groups capable of interacting in the grooves. In the second part of the paper we systematically compare MS/MS fragmentation channels and breakdown curves in the positive and the negative modes, and discuss the possible uses and caveats of MS/MS in drug-DNA complexes. In the negative mode, the drugs can be separated in three groups: (1) those that leave the complex with no net charge; (2) those that leave the complex with a negative charge; and (3) those that remain attached on the strands upon dissociation of the duplex due to their positive charge. In the positive ion mode, all complexes fragment via the loss of protonated drug. Information on the stabilization of the complex by drug-DNA noncovalent interactions can be obtained straightforwardly only in the case of neutral drug loss. In all other cases, proton affinity (in the positive ion mode), gas-phase basicity (in the negative ion mode) and coulombic repulsion are the major factors influencing the fragmentation channel and the dissociation kinetics.

  6. NLRP3 Inflammasome and MS/EAE

    PubMed Central

    Shinohara, Mari L.

    2013-01-01

    Inflammasomes are cytosolic sensors that detect pathogens and danger signals in the innate immune system. The NLRP3 inflammasome is currently the most fully characterized inflammasome and is known to detect a wide array of microbes and endogenous damage-associated molecules. Possible involvement of the NLRP3 inflammasome (or inflammasomes) in the development of multiple sclerosis (MS) was suggested in a number of studies. Recent studies showed that the NLRP3 inflammasome exacerbates experimental autoimmune encephalomyelitis (EAE), an animal model of MS, although EAE can also develop without the NLRP3 inflammasome. In this paper, we discuss the NLRP3 inflammasome in MS and EAE development. PMID:23365725

  7. Using the MMPB technique to confirm microcystin concentrations in water measured by ELISA and HPLC (UV, MS, MS/MS).

    PubMed

    Foss, Amanda J; Aubel, Mark T

    2015-09-15

    Microcystins have been detected in raw and finished drinking water using a variety of techniques, including assays (immunoassay, phosphatase inhibition) and HPLC (UV, MS/(MS)). The principal challenge to microcystin analysis is accounting for the over 150 variants that have been described. A confirmatory individual variant HPLC analysis is prone to under-reporting total microcystins due to method specificity. One method that allows for total microcystin quantitation is the MMPB technique. In this study, water samples with native microcystins were oxidized to cleave the Adda moiety, common to all microcystin variants. LC-MS/MS analysis was conducted on the subsequent MMPB (3-methoxy-2-methyl-4-phenylbutyric acid) molecule and calibrated using a certified reference standard (microcystin-LR) and 4-phenylbutyric acid. Total microcystin concentrations from MMPB were compared to Adda ELISA and individual variant analyses (LC-UV, LC-MS/(MS)). Variants of microcystin, including [DAsp(3)]MC-RR, [Dha(7)]MC-RR, MC-RR, MC-YR, MC-LR, [DAsp(3)]MC-LR, [Dha(7)]MC-LR, MC-WR, MC-LA, and MC-LY were detected and quantified in samples. The individual variant analyses did not account for total microcystins present in samples, as indicated by ELISA and MMPB data. Results demonstrated the MMPB technique is a simple and valuable approach to confirm ELISA data when analyzing microcystins, with method detection limits of 0.05 μg L(-1) for total microcystins.

  8. In Vivo Metabolism Study of Xiamenmycin A in Mouse Plasma by UPLC-QTOF-MS and LC-MS/MS

    PubMed Central

    Lei, Feng; Gao, Du; Zhang, Xi; Xu, Jun; Xu, Min-Juan

    2015-01-01

    Xiamenmycin A is an antifibrotic leading compound with a benzopyran skeleton that is isolated from mangrove-derived Streptomyces xiamenensis. As a promising small molecule for fibrotic diseases, less information is known about its metabolic characteristics in vivo. In this study, the time-course of xiamenmycin A in mouse plasma was investigated by relative quantification. After two types of administration of xiamenmycin A at a single dose of 10 mg/kg, the plasma concentrations were measured quantitatively by LC-MS/MS. The dynamic changes in the xiamenmycin A concentration showed rapid absorption and quick elimination in plasma post-administration. Four metabolites (M1–M4) were identified in blood by UPLC-QTOF-MS, and xiamenmycin B (M3) is the principal metabolite in vivo, as verified by comparison of the authentic standard sample. The structures of other metabolites were identified based on the characteristics of their MS and MS/MS data. The newly identified metabolites are useful for understanding the metabolism of xiamenmycin A in vivo, aiming at the development of an anti-fibrotic drug candidate for the therapeutic treatment of excessive fibrotic diseases. PMID:25636156

  9. Analysis of Thiodiglycol: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS777

    SciTech Connect

    Owens, J; Koester, C

    2008-07-24

    The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method for the analysis of thiodiglycol, the breakdown product of the sulfur mustard HD, in water by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), titled Method EPA MS777 (hereafter referred to as EPA CRL SOP MS777). This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to verify the analytical procedures described in MS777 for analysis of thiodiglycol in aqueous samples. The gathered data from this study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of Method EPA MS777 can be determined.

  10. CLaMS: Classifier for Metagenomic Sequences

    SciTech Connect

    Pati, Amrita

    2010-12-01

    CLaMS-"Classifer for Metagenonic Sequences" is a Java application for binning assembled metagenomes wings user-specified training sequence sets and other user-specified initial parameters. Since ClAmS analyzes and matches sequence composition-based genomic signatures, it is much faster than binning tools that rely on alignments to homologs; CLaMS can bin ~20,000 sequences in 3 minutes on a laptop with a 2.4 Ghz. Intel Core 2 Duo processor and 2 GB Ram. CLaMS is meant to be desktop application for biologist and can be run on any machine under any operating system on which the Java Runtime Environment is enabled. CLaMS is freely available in both GVI-based and command-line based forms.

  11. Simultaneous analysis of 17 diuretics in dietary supplements by HPLC and LC-MS/MS.

    PubMed

    Woo, H; Kim, J W; Han, K M; Lee, J H; Hwang, I S; Lee, J H; Kim, J; Kweon, S J; Cho, S; Chae, K R; Han, S Y; Kim, J

    2013-01-01

    In order to test health foods for illegally added diuretics for weight loss, we developed simple, rapid, selective, and sensitive methods using HPLC and LC-MS/MS for the simultaneous analysis of 17 diuretics in dietary supplements. HPLC conditions were set with a Capcell-pak C18, using a mobile phase consisting of gradient conditions, UV detection at 254 nm and validated for linearity (r(2)> 0.999), precision (CV ≤ 3%), recoveries (90.4-102.8%) and reproducibility. Identification and quantification of 17 diuretics were accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM). The chromatographic separation was carried out under the reversed-phase mechanism on an HSS-T3 column. The LC-MS/MS method was validated for linearity (r(2)> 0.99) and precision (CV < 13%). Sixteen dietary supplements were tested with the developed methods. Diuretics were not detected in all samples. Extraction recovery was also investigated and the extraction recoveries in different formulations were from 88% to 110% and from 81% to 116% using HPLC and LC-MS/MS, respectively. There was no significant difference in recoveries in the type of dietary supplements. Based on this result, the developed methods to monitor illegal drug adulterations in dietary supplements using HPLC and LC-MS/MS are simple, fast and reliable. Therefore, it is applicable to routine drug-adulteration screening.

  12. Determination of zinc pyrithione in shampoos by HPLC and HPLC-MS/MS.

    PubMed

    Gu, Yu-Xiang; Wang, Qing-He; Zhou, Ze-Lin; Lv, Qing; Mai, Cheng-Hua

    2014-01-01

    Methods have been developed for the determination of zinc pyrithione (ZPT) in shampoos using high-performance liquid chromatography (HPLC) and high-performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS). Samples were washed by water first to remove surfactant and water-soluble impurities, then ultrasonic-extracted by acetonitrile-methanol for 30 min, and finally analyzed by MG C18 column (250 mm x 4.6 mm, 5 μm) or RP-18e (100 mm x 3 mm, 2 μm) plus APCI-MS/MS. Limits of detection were determined as 0.015% (HPLC) and 0.003% (HPLC-MS/MS), with a limit of quantization of 0.05% and 0.01%, respectively. The recoveries were 85.8-104% (HPLC) and 87.6-107% (HPLC-MS/MS). A good linear relationship was obtained from 3.20 μg·ml(-1) to 200 μg·ml(-1) (HPLC) and 1.00 μg·ml(-1) to 200 μg·ml(-1) (HPLC-MS/MS). The proposed methods have been successfully applied to the analysis of ZPT in many shampoos. The established two methods were rapid and reproducible with low interference.

  13. 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

  14. Expert System for Computer-assisted Annotation of MS/MS Spectra*

    PubMed Central

    Neuhauser, Nadin; Michalski, Annette; Cox, Jürgen; Mann, Matthias

    2012-01-01

    An important step in mass spectrometry (MS)-based proteomics is the identification of peptides by their fragment spectra. Regardless of the identification score achieved, almost all tandem-MS (MS/MS) spectra contain remaining peaks that are not assigned by the search engine. These peaks may be explainable by human experts but the scale of modern proteomics experiments makes this impractical. In computer science, Expert Systems are a mature technology to implement a list of rules generated by interviews with practitioners. We here develop such an Expert System, making use of literature knowledge as well as a large body of high mass accuracy and pure fragmentation spectra. Interestingly, we find that even with high mass accuracy data, rule sets can quickly become too complex, leading to over-annotation. Therefore we establish a rigorous false discovery rate, calculated by random insertion of peaks from a large collection of other MS/MS spectra, and use it to develop an optimized knowledge base. This rule set correctly annotates almost all peaks of medium or high abundance. For high resolution HCD data, median intensity coverage of fragment peaks in MS/MS spectra increases from 58% by search engine annotation alone to 86%. The resulting annotation performance surpasses a human expert, especially on complex spectra such as those of larger phosphorylated peptides. Our system is also applicable to high resolution collision-induced dissociation data. It is available both as a part of MaxQuant and via a webserver that only requires an MS/MS spectrum and the corresponding peptides sequence, and which outputs publication quality, annotated MS/MS spectra (www.biochem.mpg.de/mann/tools/). It provides expert knowledge to beginners in the field of MS-based proteomics and helps advanced users to focus on unusual and possibly novel types of fragment ions. PMID:22888147

  15. Ecological Epigenetics: Beyond MS-AFLP.

    PubMed

    Schrey, Aaron W; Alvarez, Mariano; Foust, Christy M; Kilvitis, Holly J; Lee, Jacob D; Liebl, Andrea L; Martin, Lynn B; Richards, Christina L; Robertson, Marta

    2013-08-01

    Ecological Epigenetics studies the relationship between epigenetic variation and ecologically relevant phenotypic variation. As molecular epigenetic mechanisms often control gene expression, even across generations, they may impact many evolutionary processes. Multiple molecular epigenetic mechanisms exist, but methylation of DNA so far has dominated the Ecological Epigenetic literature. There are several molecular techniques used to screen methylation of DNA; here, we focus on the most common technique, methylation-sensitive-AFLP (MS-AFLP), which is used to identify genome-wide methylation patterns. We review studies that used MS-AFLP to address ecological questions, that describe which taxa have been investigated, and that identify general trends in the field. We then discuss, noting the general themes, four studies across taxa that demonstrate characteristics that increase the inferences that can be made from MS-AFLP data; we suggest that future MS-AFLP studies should incorporate these methods and techniques. We then review the short-comings of MS-AFLP and suggest alternative techniques that might address some of these limitations. Finally, we make specific suggestions for future research on MS-AFLP and identify questions that are most compelling and tractable in the short term.

  16. Fast MS/MS acquisition without dynamic exclusion enables precise and accurate quantification of proteome by MS/MS fragment intensity

    PubMed Central

    Zhang, Shen; Wu, Qi; Shan, Yichu; Zhao, Qun; Zhao, Baofeng; Weng, Yejing; Sui, Zhigang; Zhang, Lihua; Zhang, Yukui

    2016-01-01

    Most currently proteomic studies use data-dependent acquisition with dynamic exclusion to identify and quantify the peptides generated by the digestion of biological sample. Although dynamic exclusion permits more identifications and higher possibility to find low abundant proteins, stochastic and irreproducible precursor ion selection caused by dynamic exclusion limit the quantification capabilities, especially for MS/MS based quantification. This is because a peptide is usually triggered for fragmentation only once due to dynamic exclusion. Therefore the fragment ions used for quantification only reflect the peptide abundances at that given time point. Here, we propose a strategy of fast MS/MS acquisition without dynamic exclusion to enable precise and accurate quantification of proteome by MS/MS fragment intensity. The results showed comparable proteome identification efficiency compared to the traditional data-dependent acquisition with dynamic exclusion, better quantitative accuracy and reproducibility regardless of label-free based quantification or isobaric labeling based quantification. It provides us with new insights to fully explore the potential of modern mass spectrometers. This strategy was applied to the relative quantification of two human disease cell lines, showing great promises for quantitative proteomic applications. PMID:27198003

  17. Enantioselective quantification of chiral drugs in human plasma with LC-MS/MS.

    PubMed

    Liu, Ke; Zhong, Dafang; Chen, Xiaoyan

    2009-06-01

    Today, approximately 60% of synthetic drugs are chiral and 88% of these chiral synthetic drugs are used therapeutically as racemates. However, for many racemic drugs, their stereospecific plasma pharmacokinetics in humans are not known due to the limitations of the analytical methods. Nowadays, liquid chromatography (LC)-tandem mass spectrometry (MS/MS) methods based on various chiral stationary phases (CSPs), with a high degree of specificity and sensitivity, have been widely used in enantioselective determination of chiral drugs and/or their metabolites in human plasma. The technologies and issues when coupling chiral chromatography with MS/MS detection in bioanalytical methods will be reviewed herein. The introduction and applications of various CPSs, including polysaccharide-, macrocyclic glycopeptide-, protein- and cyclodextrin-based phases, are described here. This review also includes a discussion of interface and matrix effects in enantioselective LC-MS/MS methods.

  18. OpenMS and TOPP: open source software for LC-MS data analysis.

    PubMed

    Reinert, Knut; Kohlbacher, Oliver

    2010-01-01

    The automatic analysis of mass spectrometry data is becoming more and more important since increasingly larger datasets are readily available that cannot be evaluated manually. This has triggered the development of several open-source software libraries for the automatic analysis of such data. Among those is OpenMS together with TOPP (The OpenMS Proteomics Pipeline). OpenMS is a C++ library for rapid prototyping of complex algorithms for the analysis of mass spectrometry data. Based on the OpenMS library, TOPP provides a collection of tools for the most important tasks in proteomics analysis. The tight coupling of OpenMS and TOPP makes it easy to extend TOPP by adding new tools to the OpenMS library. We describe the overall concepts behind the software and illustrate its use with several examples.

  19. Online nanoscale ERLIC-MS outperforms RPLC-MS for shotgun proteomics in complex mixtures.

    PubMed

    de Jong, Ebbing P; Griffin, Timothy J

    2012-10-05

    We have explored the use of electrostatic repulsion hydrophilic interaction chromatography (ERLIC) as an alternative to the gold-standard in shotgun proteomics: reversed-phase (RP) LC for online ESI-MS/MS. Conditions for sample solubilization and initial gradient conditions were optimized to strike a balance between peptide solubility and maximum peptide retention when using mobile phase with high organic solvent concentration. Online ERLIC-MS demonstrated a 57% increase in total peptide identifications compared to RP-MS. We examined the mechanism of this improved performance and found that it stems from ERLIC's propensity to retain longer peptides, which can be identified with greater confidence. Online nanoscale ERLIC-MS provides a powerful new tool for enhancing MS-based shotgun proteomic in a broad range of applications.

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

    SciTech Connect

    Owens, J; Koester, C

    2008-05-14

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

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

    SciTech Connect

    Owens, J; Vu, A; Koester, C

    2008-10-08

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

  2. Isolation and characterization of a male fertility gene (Ms4) in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying a stable male-sterility system is crucial for the development of hybrid soybean. In soybean, eleven male-sterile, female-fertile mutants (ms1, ms2, ms3, ms4, ms5, ms6, ms7, ms8, ms9, msMOS, and msp) have been identified and some of which have been mapped to soybean chromosomes. The objec...

  3. Vitamin D and Multiple Sclerosis (MS): Is There Any Connection?

    MedlinePlus

    ... and MS is strengthened by the association between sunlight and the risk of MS. The farther away ... person lives, the higher the risk of MS. Sunlight is the body's most efficient source for vitamin ...

  4. Two Time Point MS Lesion Segmentation in Brain MRI: An Expectation-Maximization Framework

    PubMed Central

    Jain, Saurabh; Ribbens, Annemie; Sima, Diana M.; Cambron, Melissa; De Keyser, Jacques; Wang, Chenyu; Barnett, Michael H.; Van Huffel, Sabine; Maes, Frederik; Smeets, Dirk

    2016-01-01

    Purpose: Lesion volume is a meaningful measure in multiple sclerosis (MS) prognosis. Manual lesion segmentation for computing volume in a single or multiple time points is time consuming and suffers from intra and inter-observer variability. Methods: In this paper, we present MSmetrix-long: a joint expectation-maximization (EM) framework for two time point white matter (WM) lesion segmentation. MSmetrix-long takes as input a 3D T1-weighted and a 3D FLAIR MR image and segments lesions in three steps: (1) cross-sectional lesion segmentation of the two time points; (2) creation of difference image, which is used to model the lesion evolution; (3) a joint EM lesion segmentation framework that uses output of step (1) and step (2) to provide the final lesion segmentation. The accuracy (Dice score) and reproducibility (absolute lesion volume difference) of MSmetrix-long is evaluated using two datasets. Results: On the first dataset, the median Dice score between MSmetrix-long and expert lesion segmentation was 0.63 and the Pearson correlation coefficient (PCC) was equal to 0.96. On the second dataset, the median absolute volume difference was 0.11 ml. Conclusions: MSmetrix-long is accurate and consistent in segmenting MS lesions. Also, MSmetrix-long compares favorably with the publicly available longitudinal MS lesion segmentation algorithm of Lesion Segmentation Toolbox. PMID:28066162

  5. Two Time Point MS Lesion Segmentation in Brain MRI: An Expectation-Maximization Framework.

    PubMed

    Jain, Saurabh; Ribbens, Annemie; Sima, Diana M; Cambron, Melissa; De Keyser, Jacques; Wang, Chenyu; Barnett, Michael H; Van Huffel, Sabine; Maes, Frederik; Smeets, Dirk

    2016-01-01

    Purpose: Lesion volume is a meaningful measure in multiple sclerosis (MS) prognosis. Manual lesion segmentation for computing volume in a single or multiple time points is time consuming and suffers from intra and inter-observer variability. Methods: In this paper, we present MSmetrix-long: a joint expectation-maximization (EM) framework for two time point white matter (WM) lesion segmentation. MSmetrix-long takes as input a 3D T1-weighted and a 3D FLAIR MR image and segments lesions in three steps: (1) cross-sectional lesion segmentation of the two time points; (2) creation of difference image, which is used to model the lesion evolution; (3) a joint EM lesion segmentation framework that uses output of step (1) and step (2) to provide the final lesion segmentation. The accuracy (Dice score) and reproducibility (absolute lesion volume difference) of MSmetrix-long is evaluated using two datasets. Results: On the first dataset, the median Dice score between MSmetrix-long and expert lesion segmentation was 0.63 and the Pearson correlation coefficient (PCC) was equal to 0.96. On the second dataset, the median absolute volume difference was 0.11 ml. Conclusions: MSmetrix-long is accurate and consistent in segmenting MS lesions. Also, MSmetrix-long compares favorably with the publicly available longitudinal MS lesion segmentation algorithm of Lesion Segmentation Toolbox.

  6. Reliable procedures to evaluate and repair crosstalk for bioanalytical MS/MS assays.

    PubMed

    Morin, Louis-Philippe; Mess, Jean-Nicholas; Furtado, Milton; Garofolo, Fabio

    2011-02-01

    Louis-Philippe Morin is a senior instrument application specialist at Algorithme Pharma, a CRO located in Laval, Canada. He has been working in the bioanalysis industry for the past 10 years where he became a subject matter expert in analytical instrumentation, especially in the MS field. His responsibilities in his current position are to optimize the workflow of the laboratory and to find new procedures, or approaches, to fix complex analytical problems. Louis-Philippe's expertise acquired over the years has led him to multiple publications regarding instrumentation. LC-MS/MS is the analytical technique of choice for the quantification of drugs in biological fluids. In recent years, MS/MS detection has been impacted by the rapid evolution of bioanalysis industry requirements. The availability of fast chromatographic systems, the demand for wider dynamic ranges and the extensive use of stable isotope-labeled internal standards in bioanalysis has pushed some triple quadrupole detectors to their limits of operation. Consequently, this situation has led to a re-evaluation of the problem of crosstalk as a potential cause of issues in bioanalysis. In this article, the importance of crosstalk verification on the MS/MS instrument will be demonstrated. Additionally, procedures to identify, evaluate and fix possible crosstalk issues during bioanalytical assays on MS/MS instruments are proposed.

  7. Analysis of Combustion Chamber Deposits by ESI-TOF-MS and MALDI-TOF-MS

    SciTech Connect

    Reynolds, J G; Shields, S J; Roos, J W

    2001-06-14

    Combustion chamber deposits (CCDs) in internal combustion engines have been studied by various techniques to understand the relationship of performance degradation with deposit quantity and structure. XPS, XAS, NMR, and elemental analysis have offered insight into the bulk structure of C, H, N, O and metal components [1]. MS has offered some information about compound structure, but results are limited due to the insolubility and complexity of the materials. Recent advances in MS have opened new possibilities for analysis of CCDs. Here we report initial findings on the carbon structure of these deposits determined by ESI-TOF-MS and MADLI-TOF-MS.

  8. Improving natural products identification through targeted LC-MS/MS in an untargeted secondary metabolomics workflow.

    PubMed

    Hoffmann, Thomas; Krug, Daniel; Hüttel, Stephan; Müller, Rolf

    2014-11-04

    Tandem mass spectrometry is a widely applied and highly sensitive technique for the discovery and characterization of microbial natural products such as secondary metabolites from myxobacteria. Here, a data mining workflow based on MS/MS precursor lists targeting only signals related to bacterial metabolism is established using LC-MS data of crude extracts from shaking flask fermentations. The devised method is not biased toward specific compound classes or structural features and is capable of increasing the information content of LC-MS/MS analyses by directing fragmentation events to signals of interest. The approach is thus contrary to typical auto-MS(2) setups where precursor ions are usually selected according to signal intensity, which is regarded as a drawback for metabolite discovery applications when samples contain many overlapping signals and the most intense signals do not necessarily represent compounds of interest. In line with this, the method described here achieves improved MS/MS scan coverage for low-abundance precursor ions not captured by auto-MS(2) experiments and thereby facilitates the search for new secondary metabolites in complex biological samples. To underpin the effectiveness of the approach, the identification and structure elucidation of two new myxobacterial secondary metabolite classes is reported.

  9. 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.

  10. Leveraging EMS and VPP

    DTIC Science & Technology

    2009-05-01

    Elements of EMS  International Standards Organization ( ISO ) 14001 , Environmental Management Systems  The Key Elements of EMS: - Policy - Planning...wingman-- ON and OFF duty Fully Conforming vs. Fully Implemented  “Fully Conforming”  Meets standards established in ISO 14001  ESOH council...e n c e Every airman looking out for his wingman-- ON and OFF duty EMS & VPP Commonalities Environmental Management System ISO 14001 : 2004 Voluntary

  11. Metabolic profiling of roots of liquorice (Glycyrrhiza glabra) from different geographical areas by ESI/MS/MS and determination of major metabolites by LC-ESI/MS and LC-ESI/MS/MS.

    PubMed

    Montoro, Paola; Maldini, Mariateresa; Russo, Mariateresa; Postorino, Santo; Piacente, Sonia; Pizza, Cosimo

    2011-02-20

    Liquid chromatography electrospray mass spectrometry (LC-ESI/MS) has been applied to the full characterization of saponins and phenolics in hydroalcoholic extracts of roots of liquorice (Glycyrrhiza glabra). Relative quantitative analyses of the samples with respect to the phenolic constituents and to a group of saponins related to glycyrrhizic acid were performed using LC-ESI/MS. For the saponin constituents, full scan LC-MS/MS fragmentation of the protonated (positive ion mode) or deprotonated (negative ion mode) molecular species generated diagnostic fragment ions that provided information concerning the triterpene skeleton and the number and nature of the substituents. On the basis of the specific fragmentation of glycyrrhizic acid, an LC-MS/MS method was developed in order to quantify the analyte in the liquorice root samples. Chinese G. glabra roots contained the highest levels of glycyrrhizic acid, followed by those from Italy (Calabria).

  12. The pinhole interface for IMS/MS

    NASA Technical Reports Server (NTRS)

    Spangler, Glenn E.

    1995-01-01

    An important supplementary technique for ion mobility spectrometry (IMS) is mass spectrometry (MS). A mass spectrometer coupled to an ion mobility spectrometer (IMS/MS) can provide significant information on the composition of the ions contributing to an ion mobility peak. On the other hand, the interpretation of IMS/MS results requires knowledge of processes which can occur at the pinhole interface. When the ion composition is a mixture of ion clusters, the observed cluster distribution may not be an accurate representation of the ion clusters in the IMS. Depending on the buffer gas, lower clusters can form by equilibrating with reduced concentrations in the continuum regime of the expansion and larger clusters can form by collisional stabilization in the cooled jet stream. Besides water, nitrogen molecules can also add to the ion clusters. Even though nitrogen is non-polar, this addition is made possible by an ion-induced dipole interaction between the ion and molecule.

  13. STS-47 MS Davis and MS Jemison with LBNP device in SLJ module aboard OV-105

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-47 Mission Specialist (MS) N. Jan Davis (left) and MS Mae C. Jemison prepare the lower body negative pressure (LBNP) device for the LBNP experiment in the Spacelab Japan (SLJ) science module aboard the Earth-orbiting Endeavour, Orbiter Vehicle (OV) 105. Displayed on the aft end cone in the background is an Auburn University banner.

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

    EPA Science Inventory

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

  15. Natural isotope correction of MS/MS measurements for metabolomics and (13)C fluxomics.

    PubMed

    Niedenführ, Sebastian; ten Pierick, Angela; van Dam, Patricia T N; Suarez-Mendez, Camilo A; Nöh, Katharina; Wahl, S Aljoscha

    2016-05-01

    Fluxomics and metabolomics are crucial tools for metabolic engineering and biomedical analysis to determine the in vivo cellular state. Especially, the application of (13)C isotopes allows comprehensive insights into the functional operation of cellular metabolism. Compared to single MS, tandem mass spectrometry (MS/MS) provides more detailed and accurate measurements of the metabolite enrichment patterns (tandem mass isotopomers), increasing the accuracy of metabolite concentration measurements and metabolic flux estimation. MS-type data from isotope labeling experiments is biased by naturally occurring stable isotopes (C, H, N, O, etc.). In particular, GC-MS(/MS) requires derivatization for the usually non-volatile intracellular metabolites introducing additional natural isotopes leading to measurements that do not directly represent the carbon labeling distribution. To make full use of LC- and GC-MS/MS mass isotopomer measurements, the influence of natural isotopes has to be eliminated (corrected). Our correction approach is analyzed for the two most common applications; (13)C fluxomics and isotope dilution mass spectrometry (IDMS) based metabolomics. Natural isotopes can have an impact on the calculated flux distribution which strongly depends on the substrate labeling and the actual flux distribution. Second, we show that in IDMS based metabolomics natural isotopes lead to underestimated concentrations that can and should be corrected with a nonlinear calibration. Our simulations indicate that the correction for natural abundance in isotope based fluxomics and quantitative metabolomics is essential for correct data interpretation.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. A multiclass multiresidue LC-MS/MS method for analysis of veterinary drugs in bovine kidney

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased efficiency permitted by multiclass, multiresidue methods has made such approaches very attractive to laboratories involved in monitoring veterinary drug residues in animal tissues. In this current work, evaluation of a multiclass multiresidue LC-MS/MS method in bovine kidney is describ...

  18. Sample preparation for proteomic analysis using a GeLC-MS/MS strategy.

    PubMed

    Paulo, Joao A

    In-gel digestion coupled with mass spectrometric analysis (GeLC-MS/MS) is a cornerstone for protein identification and characterization. Here I review this versatile approach which combines classical and modern biochemistry strategies and allows for targeted and proteome-wide analyses. Starting with any protein sample, reduced and alkylated proteins are precipitated prior to fractionation by SDS-PAGE. Proteins are in-gel digested and the resulting peptides are extracted and desalted for downstream LC-MS/MS analysis. GeLC-MS/MS leverages the advantages of both traditional SDS-PAGE visualization and protein fractionation with the robust protein and post-translational modification identification and quantitation capabilities of state-of-the-art mass spectrometry-based technology. As such, this strategy allows for the visible assessment of protein amount and quality, prior to analysis via virtually any mass spectrometry platform. Moreover, gel extracted peptides may be derived from any sample type-e.g., from cell culture, tissue, body fluid, or recombinantly-expressed protein-and are fully compatible with isobaric tagging. GeLC-MS/MS is an invaluable technique for proteomic analyses.

  19. STS-44 MS Runco and MS Voss pose with EMUs in OV-104's airlock

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-44 Mission Specialist (MS) Mario Runco, Jr (left) and MS James S. Voss pose with two extravehicular mobility units (EMUs) in Atlantis', Orbiter Vehicle (OV) 104's, airlock. The EMUs are mounted on airlock adapter plates (AAPs) and have lower torso restraints in place. They are stowed in the airlock and will be used in the event of a contingency extravehicular activity (EVA).

  20. 12 CFR Appendix Ms-3 to Part 1024 - Appendix MS-3 to Part 1024

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... you buy yourself. If you have any questions, please contact us at . MS-3(B)—Model Form for Force... have any questions, please contact us at . MS-3(C)—Model Form for Force-Placed Insurance Notice... have any questions, please contact us at . Effective Date Notes: 1. At 78 FR 10886, Feb. 14,...

  1. An impulse-driven liquid-droplet deposition interface for combining LC with MALDI MS and MS/MS.

    PubMed

    Young, J Bryce; Li, Liang

    2006-03-01

    A simple and robust impulse-driven droplet deposition system was developed for off-line liquid chromatography matrix-assisted laser desorption ionization mass spectrometry (LC-MALDI MS). The system uses a solenoid operated with a pulsed voltage power supply to generate impulses that dislodge the hanging droplets from the LC outlet directly to a MALDI plate via a momentum transfer process. There is no contact between the LC outlet and the collection surface. The system is compatible with solvents of varying polarity and viscosity, and accommodates the use of hydrophobic and hydrophilic MALDI matrices. MALDI spots are produced on-line with the separation, and do not require further processing before MS analysis. It is shown that high quality MALDI spectra from 5 fmol of pyro-Glu-fibrinopeptide deposition after LC separation could be obtained using the device, indicating that there was no sample loss in the interface. To demonstrate the analytical performance of the system as a proteome analysis tool, a range of BSA digest concentrations covering about 3 orders of magnitude, from 5 fmol to 1 pmol, were analyzed by LC-MALDI quadrupole time-of-flight MS, yielding 6 and 57% amino acid sequence coverage, respectively. In addition, a complex protein mixture of an E. coli cell extract was tryptically digested and analyzed by LC-MALDI MS, resulting in the detection of a total of 409 unique peptides from 100 fractions of 15-s intervals.

  2. Rapid sample pre-treatment prior to GC-MS and GC-MS/MS urinary toxicological screening.

    PubMed

    Versace, François; Sporkert, Frank; Mangin, Patrice; Staub, Christian

    2012-11-15

    Drug screening is an important issue in clinical and forensic toxicology. Gas chromatography coupled to mass spectrometry (GC-MS) remains the gold standard technique for the screening of unknown compounds in urine samples. However, this technique requires substantial sample preparation, which is time consuming. Moreover, some common drugs such as cannabis cannot be easily detected in urine using general procedures. In this work, a sample preparation protocol for treating 200 μL of urine in less than 30 min is described. The enzymatic hydrolysis of glucuro-conjugates was performed in 5 min thanks to the use of microwaves. The use of a deconvolution software allowed reducing the GC-MS run to 10 min, without impairing the quality of the compound identifications. Comparing the results from 139 authentic urine samples to those obtained using the current routine analysis indicated this method performed well. Moreover, additional 5-min GC-MS/MS programs are described, enabling a very sensitive target screening of 54 drugs, including THC-COOH or buprenorphine, without further sample preparation. These methods appeared as an interesting alternative to immuno-assays based screening. The analytical strategy presented in this article proved to be a promising approach for systematic toxicological analysis (STA) of drugs in urine.

  3. Neuronal Determinants of Motor Disability in MS

    DTIC Science & Technology

    2015-10-01

    between approximately 6 to 8 months delayed from the original SOW primarily due to delays in human subject authorization steps. 15. SUBJECT TERMS Motor...Motor disability is one of the primary disabling features of MS and is predictive of an aggressive progressive course of the disease . However, to...neuron  injury,  function,  and  loss   and   disease  related  metrics  in  MS  patients  at  a  baseline  and  1

  4. LC-MS-MS Method for Analysis of Opiates in Wastewater During Football Games II.

    PubMed

    Gul, Waseem; Stamper, Brandon; Godfrey, Murrell; Gul, Shahbaz W; ElSohly, Mahmoud A

    2016-06-01

    Continuing our previous studies analyzing drugs of abuse in municipal wastewater, a method was developed for the analysis of opiates in wastewater samples using liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). Eight opiate drugs and metabolites were analyzed including codeine, hydrocodone, hydromorphone, 6-monoacetylmorphine (6-MAM, the primary urinary metabolite of heroin), morphine, norhydrocodone (the primary urinary metabolite of hydrocodone), oxycodone and oxymorphone. These drugs were chosen because of their widespread abuse. Wastewater samples were collected at both the Oxford Waste Water Treatment Plant in Oxford, Mississippi (MS) and the University Wastewater Treatment Plant in University, MS. These wastewater samples were collected on weekends in which the Ole Miss Rebel football team held home games (Vaught-Hemingway Stadium, University, MS 38677). The collected samples were analyzed using a validated method and found to contain codeine, hydrocodone, hydromorphone, morphine, norhydrocodone, oxycodone and oxymorphone. None of the samples contained 6-MAM.

  5. Determination of steroidal glycosides in Yucca gloriosa flowers by LC/MS/MS.

    PubMed

    Montoro, Paola; Skhirtladze, Alexandre; Perrone, Angela; Benidze, Mariam; Kemertelidze, Ether; Piacente, Sonia

    2010-09-05

    An high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (MS/MS) method, was developed for the quantitative analysis of the steroidal glycosides occurring in Yucca gloriosa flowers. The HPLC experiments were performed by means of an octadecyl-modified reversed-phase C-18 column and a binary mobile phase system under gradient elution conditions. The fragmentation patterns of steroidal saponins were analyzed by ESI-MS(n) in positive ion mode and a specific multiple reaction monitoring MS/MS detection was developed for their quantitative determination. The described method provides high sensitivity and specificity for quantitative determination of the steroidal glycosides in Y. gloriosa flowers. Quantification was performed against an external calibration line obtained using each pure steroidal glycoside. Short- and long-term repeatabilities of the methods were better than 3 and 6%, respectively. The method was validated according to EMEA guidelines and applied to real samples.

  6. MS/MS similarity networking accelerated target profiling of triterpene saponins in Eleutherococcus senticosus leaves.

    PubMed

    Ge, Yue-Wei; Zhu, Shu; Yoshimatsu, Kayo; Komatsu, Katsuko

    2017-07-15

    The targeted mass information of compounds accelerated their discovery in a large volume of untargeted MS data. An MS/MS similarity networking is advanced in clustering the structural analogues, which benefits the collection of mass information of similar compounds. The triterpene saponins extracted from Eleutherococcus senticosus leaves (ESL), a kind of functional tea, have shown promise in the relief of Alzheimer's disease. In this work, a target-precursor list (TPL) generated using MS/MS similarity networking was employed to rapidly trace 106 triterpene saponins from the aqueous extracts of ESL, of which 49 were tentatively identified as potentially new triterpene saponins. Moreover, a compound database of triterpene saponins was established and successfully applied to uncover their distribution features in ESL samples collected from different areas.

  7. Screening for Expressed Nonribosomal Peptide Synthetases and Polyketide Synthases Using LC-MS/MS-Based Proteomics

    PubMed Central

    Chen, Yunqiu; McClure, Ryan A.; Kelleher, Neil L.

    2016-01-01

    Liquid chromatography–mass spectrometry (LC-MS)-based proteomics is a powerful technique for the profiling of protein expression in cells in a high-throughput fashion. Herein we report a protocol using LC-MS/MS-based proteomics for the screening of enzymes involved in natural product biosynthesis, such as nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) from bacterial strains. Taking advantage of the large size of modular NRPSs and PKSs (often >200 kDa), size-based separation (SDS-PAGE) is employed prior to LC-MS/MS analysis. Based upon the protein identifications obtained through software search, we can accurately pinpoint the expressed NRPS and/or PKS gene clusters from a given strain and growth condition. The proteomics screening result can be used to guide the discovery of potentially new nonribosomal peptide and polyketide natural products. PMID:26831706

  8. Instrument-independent software tools for the analysis of MS-MS and LC-MS lipidomics data.

    PubMed

    Haimi, Perttu; Chaithanya, Krishna; Kainu, Ville; Hermansson, Martin; Somerharju, Pentti

    2009-01-01

    Mass spectrometry (MS), particularly electrospray-MS, is the key tool in modern lipidomics. However, as even a modest scale experiment produces a great amount of data, data processing often becomes limiting. Notably, the software provided with MS instruments are not well suited for quantitative analysis of lipidomes because of the great variety of species present and complexities in response calibration. Here we describe the use of two recently introduced software tools: lipid mass spectrum analysis (LIMSA) and spectrum extraction from chromatographic data (SECD), which significantly increase the speed and reliability of mass spectrometric analysis of complex lipidomes. LIMSA is a Microsoft Excel add-on that (1) finds and integrates the peaks in an imported spectrum, (2) identifies the peaks, (3) corrects the peak areas for overlap by isotopic peaks of other species and (4) quantifies the identified species using included internal standards. LIMSA is instrument-independent because it processes text-format MS spectra. Typically, the analysis of one spectrum takes only a few seconds.The SECD software allows one to display MS chromatograms as two-dimensional maps, which is useful for visual inspection of the data. More importantly, however, SECD allows one to extract mass spectra from user-defined regions of the map for further analysis with, e.g., LIMSA. The use of select regions rather than simple time-range averaging significantly improves the signal-to-noise ratio as signals outside the region of interest are more efficiently excluded. LIMSA and SECD have proven to be robust and convenient tools and are available free of charge from the authors.

  9. Dopamine, T cells and multiple sclerosis (MS).

    PubMed

    Levite, Mia; Marino, Franca; Cosentino, Marco

    2017-03-10

    Dopamine is a key neurotransmitter that induces critical effects in the nervous system and in many peripheral organs, via 5 dopamine receptors (DRs): D1R-D5R. Dopamine also induces many direct and very potent effects on many DR-expressing immune cells, primarily T cells and dendritic cells. In this review, we focus only on dopamine receptors, effects and production in T cells. Dopamine by itself (at an optimal concentration of~0.1 nM) induces multiple function of resting normal human T cells, among them: T cell adhesion, chemotactic migration, homing, cytokine secretion and others. Interestingly, dopamine activates resting effector T cells (Teffs), but suppresses regulatory T cells (Tregs), and both effects lead eventually to Teff activation. Dopamine-induced effects on T cells are dynamic, context-sensitive and determined by the: T cell activation state, T cell type, DR type, and dopamine concentration. Dopamine itself, and also few dopaminergic molecules/ drugs that are in clinical use for cardiac, neurological and other non-immune indications, have direct effects on human T cells (summarized in this review). These dopaminergic drugs include: dopamine = intropin, L-DOPA, bromocriptine, pramipexole, pergolide, haloperidol, pimozide, and amantadine. Other dopaminergic drugs were not yet tested for their direct effects on T cells. Extensive evidence in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) show dopaminergic dysregulations in T cells in these diseases: D1-like DRs are decreased in Teffs of MS patients, and dopamine does not affect these cells. In contrast, D1-like DRs are increased in Tregs of MS patients, possibly causing functional Treg impairment in MS. Treatment of MS patients with interferon β (IFN-β) increases D1-like DRs and decreases D2-like DRs in Teffs, decreases D1-like DRs in Tregs, and most important: restores responsiveness of patient's Teffs to dopamine. DR agonists and antagonists confer some benefits in

  10. Ms. Affirmation and Her Technicolor Responses.

    ERIC Educational Resources Information Center

    Johnson-Kuby, Sue Ann; Katz, Claudia Anne

    1997-01-01

    Presents four questions from teachers regarding "classroom dilemmas" (such as seating assignments, requests for bathroom visits, and parent/teacher communication) with the responses by "Ms. Affirmation," a middle-school guidance counselor who collaborates with teachers to assist them in working with students. (SR)

  11. 78 FR 25336 - Mississippi Disaster # MS-00066

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00066 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... Application Deadline Date: 01/21/2014. ADDRESSES: Submit completed loan applications to: U.S. Small...

  12. 78 FR 3494 - Mississippi Disaster #MS-00063

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-16

    ... ADMINISTRATION Mississippi Disaster MS-00063 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Mississippi dated 01... adversely affected by the disaster: Primary Counties: Pearl River. Contiguous Counties: Mississippi;...

  13. 76 FR 28120 - Mississippi Disaster #MS-00047

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00047 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of Mississippi (FEMA- 1972-DR), dated 04/29/2011. Incident: Severe Storms, Tornadoes,...

  14. 75 FR 25305 - Mississippi Disaster #MS-00036

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00036 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This... State of Mississippi (FEMA- 1906-DR), dated 04/29/2010. Incident: Severe Storms, Tornadoes, and...

  15. 78 FR 13393 - Mississippi Disaster # MS-00065

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00065 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of Mississippi (FEMA- 4101-DR), dated 02/19/2013. Incident: Severe Storms, Tornadoes, and...

  16. 77 FR 55890 - Mississippi Disaster # MS-00059

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... ADMINISTRATION Mississippi Disaster MS-00059 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Mississippi (FEMA... Only): Mississippi: Forrest, George, Lamar, Marion, Stone. Alabama: Mobile. Louisiana: Saint...

  17. 76 FR 43368 - Mississippi Disaster #MS-00049

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-20

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00049 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of Mississippi (FEMA- 1983-DR), dated 07/12/2011. Incident: Flooding. Incident Period:...

  18. 75 FR 79064 - Mississippi Disaster #MS-00042

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-17

    ... ADMINISTRATION Mississippi Disaster MS-00042 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Mississippi dated 12...: Mississippi: Chickasaw, Choctaw, Clay, Itawamba, Lee, Lowndes, Noxubee, Webster, Winston. Alabama:...

  19. 75 FR 29371 - Mississippi Disaster #MS-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-25

    ... ADMINISTRATION Mississippi Disaster MS-00037 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Mississippi (FEMA..., Lafayette, Tippah, Tishomingo. Contiguous Counties (Economic Injury Loans Only): Mississippi:...

  20. 76 FR 29810 - Mississippi Disaster #MS-00048

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... ADMINISTRATION Mississippi Disaster MS-00048 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Mississippi (FEMA...): Mississippi: Amite, Attala, Copiah, Franklin, Hinds, Holmes, Leflore, Lincoln, Madison, Marshall,...

  1. 76 FR 27139 - Mississippi Disaster # MS-00045

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... ADMINISTRATION Mississippi Disaster MS-00045 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Mississippi (FEMA...): Mississippi Calhoun, Chickasaw, Claiborne, Clay, Copiah, George, Itawamba, Jones, Lauderdale, Lee,...

  2. 78 FR 12805 - Mississippi Disaster #MS-00064

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... ADMINISTRATION Mississippi Disaster MS-00064 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Mississippi (FEMA... (Economic Injury Loans Only): Mississippi: Covington, Jefferson Davis, Jones, Marion, Pearl River,...

  3. 75 FR 29370 - Mississippi Disaster #MS-00039

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-25

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Mississippi Disaster MS-00039 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of Mississippi (FEMA- 1916-DR), dated 05/14/2010. Incident: Severe Storms, Tornadoes, and...

  4. MS Musgrave conducts CFES experiment on middeck

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Mission Specialist (MS) Musgrave readies biological sample plate for insertion into Continuous Flow Electrophoresis System (CFES) fluid systems opens biological sample compartment on fluid systems module and documents experiment progress at separation column with 35mm camera. CFES is located on middeck in the galley position (port side wall) with control panel ML86B and water dispenser appearing on the right.

  5. Endocrine system dynamics and MS epidemiology.

    PubMed

    Moynihan, James; Moore, Helena

    2010-05-01

    In the kidney there is a co-transport relationship in the nephron between the reabsorption of positive Na(+) ions and the reabsorption of negative ions such as uric acid anions. Uric acid acts as an anti-oxidant and it has been shown to have a sealing effect on the blood-brain barrier. The theory developed here is that chronic neurological vasoconstriction in cool environmental conditions injects an offset into the rennin-angiotensin-aldosterone system (RAAS) blood pressure control loop and reduces demand for angiotensin and aldosterone. (Aldosterone is produced in the adrenal gland and has a direct effect on renal reabsorption of Na(+) ions.) Via co-transport these conditions will reduce the body's ability to reabsorb uric acid and this in turn will weaken the integrity of the blood-brain barrier. Also, in cool environments, where levels of vasopressin (ADH) and aldosterone are lower, the gain of the hypothalamus-pituitary-adrenal gland (HPA) axis is reduced so that the production average levels of ACTH, cortisone and aldosterone will be biased at a lower level and the kidney-local levels of aldosterone in particular will remain lower. This paper develops these ideas and suggests that they can help explain the traditionally-recognized latitudinal gradient in MS epidemiology. Also, acclimatization to heat encourages sweating, which should create a greater demand for the renal reabsorption of Na(+) ions which enables greater reabsorption of uric acid. Therefore people living at low latitudes should have a lower chance of hypouricemia and a lower chance of developing MS. In fact people who spend their first fifteen years in the tropics almost never go onto develop MS. And MS patients in relapse are consistently hypouricemic. This hypothesis can explain both of these facts. The paper goes onto show how the MS condition will tend to progress because of a number of self-sustaining effects: over time the immune system becomes more targeted to myelin, MS patients are

  6. Liquid chromatography electron capture dissociation tandem mass spectrometry (LC-ECD-MS/MS) versus liquid chromatography collision-induced dissociation tandem mass spectrometry (LC-CID-MS/MS) for the identification of proteins.

    PubMed

    Creese, Andrew J; Cooper, Helen J

    2007-05-01

    Electron capture dissociation (ECD) offers many advantages over the more traditional fragmentation techniques for the analysis of peptides and proteins, although the question remains: How suitable is ECD for incorporation within proteomic strategies for the identification of proteins? Here, we compare LC-ECD-MS/MS and LC-CID-MS/MS as techniques for the identification of proteins. Experiments were performed on a hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. Replicate analyses of a six-protein (bovine serum albumin, apo-transferrin, lysozyme, cytochrome c, alcohol dehydrogenase, and beta-galactosidase) tryptic digest were performed and the results analyzed on the basis of overall protein sequence coverage and sequence tag lengths within individual peptides. The results show that although protein coverage was lower for LC-ECD-MS/MS than for LC-CID-MS/MS, LC-ECD-MS/MS resulted in longer peptide sequence tags, providing greater confidence in protein assignment.

  7. LC-MS/MS for protein and peptide quantification in clinical chemistry.

    PubMed

    Rauh, Manfred

    2012-02-01

    The LC-triple quadrupole mass spectrometer (LC-MS/MS) is an increasingly common tool in the clinical laboratory. Established applications include routine assays for detecting inborn errors of metabolism, and for monitoring therapeutic drugs and steroids. Peptides and proteins in biological matrices have traditionally been quantified by immunological methods such as RIA or ELISA. These methods have the drawback of being insufficiently selective, often not allowing differentiation between the peptide and its derivatives or degradation fragments. The improved robustness and sensitivity of LC-MS-based techniques provide reliable alternatives for peptide quantification. Mass spectrometry does not require specific antibody reagents and is a powerful tool for the study of posttranslational modifications (PTM). In addition, several studies have demonstrated the utility of selected reaction monitoring (SRM) assays using stable-isotope-labelled (tryptic) peptides for quantifying proteins in human serum. Peptide-based MS/MS is a relatively new development in the measurement of clinically significant proteins, offering cost effectiveness, high throughput, multiplexed analysis and quantification, with the potential for combining the measurement of small molecules, peptides and proteins on a single technology platform. Quantitative analysis of proteins and peptides by LC-MS/MS is becoming a practical technique for clinical laboratories. To move from the laboratories of highly skilled analysts to routine clinical diagnostic laboratories requires that a number of technical hurdles be overcome in regard to sensitivity, imprecision, accuracy and the sample handling necessary for clinical use.

  8. Quantitative determination of paralytic shellfish toxins in cultured toxic algae by LC-MS/MS.

    PubMed

    Watanabe, Ryuichi; Matsushima, Ryoji; Harada, Tomoko; Oikawa, Hiroshi; Murata, Masakazu; Suzuki, Toshiyuki

    2013-01-01

    We developed a sample preparation and LC-MS/MS method for the determination of saxitoxins in toxic algae. Paralytic shellfish toxins (PSTs) were successfully separated by gradient elution on an amide column with the hydrophilic interaction mode and quantified with multiple reaction monitoring (MRM) detection in the positive ion mode. This method showed good performance in the summed LODs and LOQs for all 12 toxins, 25 and 84 nM, respectively. Next, extracts of cultured strains of a toxic dinoflagellate Alexandrium tamarense and a freshwater cyanobacteria Anabaena circinalis were treated in a short column of basic alumina and the toxic fractions were analysed by our LC-MS/MS method and by HPLC with fluorescence detection. Comparison of the results obtained by the two methods demonstrated that approximately equivalent results were obtained for both the dinoflagellate and the cyanobacteria. In addition, the retention time of the toxins showed acceptable shifts. Therefore, the clean-up of the toxic algal extracts by using the basic alumina column controlled unwanted chromatographic behaviour and variable ionisation efficiency during MS detection. LC-MS/MS for saxitoxins has great potential as a rapid analytical method for determining all primary saxitoxins in cultured algae.

  9. Positional isomer differentiation of synthetic cannabinoid JWH-081 by GC-MS/MS.

    PubMed

    Kusano, Maiko; Zaitsu, Kei; Nakayama, Hiroshi; Nakajima, Junichi; Hisatsune, Kazuaki; Moriyasu, Takako; Matsuta, Shuntaro; Katagi, Munehiro; Tsuchihashi, Hitoshi; Ishii, Akira

    2015-03-01

    Like many new designer drugs of abuse, synthetic cannabinoids (SC) have structural or positional isomers which may or may not all be regulated under law. Differences in acute toxicity may exist between isomers which impose further burden in the fields of forensic toxicology, medicine and legislation. Isomer differentiation therefore becomes crucial from these standpoints as new designer drugs continuously emerge with just minor positional modifications to their preexisting analogs. The aim of this study was to differentiate the positional isomers of JWH-081. Purchased standard compounds of JWH-081 and its positional isomers were analyzed by gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) first in scan mode to investigate those isomers who could be differentiated by EI scan spectra. Isomers with identical or near-identical EI spectra were further subjected to GC-tandem mass spectrometry (MS/MS) analysis with appropriate precursor ions. EI scan was able to distinguish 3 of the 7 isomers: 2-methoxy, 7-methoxy and 8-methoxy. The remaining isomers exhibited near-identical spectra; hence, MS/MS was performed by selecting m/z 185 and 157 as precursor ions. 3-Methoxy and 5-methoxy isomers produced characteristic product ions that enabled the differentiation between them. Product ion spectrum of 6-methoxy isomer resembled that of JWH-081; however, the relative ion intensities were clearly different from one another. The combination of EI scan and MS/MS allowed for the regioisomeric differentiation of the targeted compounds in this study.

  10. Retinoid quantification by HPLC/MS(n)

    NASA Technical Reports Server (NTRS)

    McCaffery, Peter; Evans, James; Koul, Omanand; Volpert, Amy; Reid, Kevin; Ullman, M. David

    2002-01-01

    Retinoic acid (RA) mediates most of the biological effects of vitamin A that are essential for vertebrate survival. It acts through binding to receptors that belong to the nuclear receptor transcription factor superfamily (Mangelsdorf et al. 1994). It is also a highly potent vertebrate teratogen. To determine the function and effects of endogenous and exogenous RA, it is important to have a highly specific, sensitive, accurate, and precise analytical procedure. Current analyses of RA and other retinoids are labor intensive, of poor sensitivity, have limited specificity, or require compatibility with RA reporter cell lines (Chen et al. 1995. BIOCHEM: Pharmacol. 50: 1257-1264; Creech Kraft et al. 1994. BIOCHEM: J. 301: 111-119; Lanvers et al. 1996. J. Chromatogr. B Biomed. Appl. 685: 233-240; Maden et al. 1998. DEVELOPMENT: 125: 4133-4144; Wagner et al. 1992. DEVELOPMENT: 116: 55-66). This paper describes an HPLC/mass spectrometry/mass spectrometry product ion scan (HPLC/MS(n)) procedure for the analysis of retinoids that employs atmospheric pressure chemical ionization MS. The retinoids are separated by normal-phase column chromatography with a linear hexane-isopropanol-dioxane gradient. Each retinoid is detected by a unique series of MS(n) functions set at optimal collision-induced dissociation energy (30% to 32%) for all MS(n) steps. The scan events are divided into three segments, based on HPLC elution order, to maximize the mass spectrometer duty cycle. The all-trans, 9-cis, and 13-cis RA isomers are separated, if desired, by an isocratic hexane-dioxane-isopropanol mobile phase. This paper describes an HPLC/MS(n) procedure possessing high sensitivity and specificity for retinoids.

  11. Gaussian and linear deconvolution of LC-MS/MS chromatograms of the eight aminobutyric acid isomers.

    PubMed

    Vemula, Harika; Kitase, Yukiko; Ayon, Navid J; Bonewald, Lynda; Gutheil, William G

    2017-01-01

    Isomeric molecules present a challenge for analytical resolution and quantification, even with MS-based detection. The eight aminobutyric acid (ABA) isomers are of interest for their various biological activities, particularly γ-aminobutyric acid (GABA) and the d- and l-isomers of β-aminoisobutyric acid (β-AIBA; BAIBA). This study aimed to investigate LC-MS/MS-based resolution of these ABA isomers as their Marfey's (Mar) reagent derivatives. HPLC was able to separate three Mar-ABA isomers l-β-ABA (l-BABA), and l- and d-α-ABA (AABA) completely, with three isomers (GABA, and d/l-BAIBA) in one chromatographic cluster, and two isomers (α-AIBA (AAIBA) and d-BABA) in a second cluster. Partially separated cluster components were deconvoluted using Gaussian peak fitting except for GABA and d-BAIBA. MS/MS detection of Marfey's derivatized ABA isomers provided six MS/MS fragments, with substantially different intensity profiles between structural isomers. This allowed linear deconvolution of ABA isomer peaks. Combining HPLC separation with linear and Gaussian deconvolution allowed resolution of all eight ABA isomers. Application to human serum found a substantial level of l-AABA (13 μM), an intermediate level of l-BAIBA (0.8 μM), and low but detectable levels (<0.2 μM) of GABA, l-BABA, AAIBA, d-BAIBA, and d-AABA. This approach should be useful for LC-MS/MS deconvolution of other challenging groups of isomeric molecules.

  12. New approach to study of spilled crude oils using high resolution GC-MS (SIM) and metastable reaction monitoring GC-MS-MS.

    PubMed

    Munoz, D; Doumenq, P; Guiliano, M; Jacquot, F; Scherrer, P; Mille, G

    1997-12-12

    Polycyclic aromatic hydrocarbons (PAHs) and geochemical biomarkers are good environmental markers to study the origin and evolution of an oil spill. To have access to the greatest number of molecular ratios, no fractionation of oil into aliphatic and aromatic compounds is made. Three analytical MS approaches are tested to analyze markers in this total hydrocarbon fraction: classical quadrupole GC-MS, high resolution GC-MS (HR GC-MS) and metastable reaction monitoring GC-MS-MS (MRM GC-MS-MS). This analytical approach is used to follow the evolution of PAHs in petroleum polluted mangrove soils over 8 years by using molecular ratios between polycyclic aromatic hydrocarbons and tri- and tetracyclic terpanes.

  13. Development of LC-MS/MS method for analysis of polyphenolic compounds in juice, tea and coffee samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple and fast method for the analysis of a wide range of polyphenolic compounds in juice, tea, and coffee samples was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was based on a simple sample preparation “dilute and shoot” approach, and LC-MS/MS triple qu...

  14. Isomer-Specific Analysis of Released N-Glycans by LC-ESI MS/MS with Porous Graphitized Carbon.

    PubMed

    Kolarich, Daniel; Windwarder, Markus; Alagesan, Kathirvel; Altmann, Friedrich

    2015-01-01

    The combination of porous graphitized carbon (PGC) liquid chromatography (LC) with mass spectrometric (MS) detection probably constitutes the most elaborate single stage analysis for isomer-specific N-glycan analysis. Here, we describe sample preparation and analysis procedures for the identification of released N-glycans using PGC-LC-ESI-MS and MS/MS.

  15. Identification of a Bacteria Using Phylogenetic Relationships Revealed by MS/MS Sequencing of Tryptic Peptides Derived From Cellular Proteins

    DTIC Science & Technology

    2004-12-01

    phylogenetic relationships between bacterial species as a part of a hierarchical decision tree process. 1. INTRODUCTION The detection and...1 IDENTIFICATION OF BACTERIA USING PHYLOGENETIC RELATIONSHIPS REVEALED BY MS/MS SEQUENCING OF TRYPTIC PEPTIDES DERIVED FROM CELLULAR PROTEINS...based on analysis of an electrospray ionization (ESI)-MS/MS data for the fast classification of analyzed bacteria, using phylogenetic relationships

  16. EMS in the pueblos.

    PubMed

    Vigil, M A

    1994-02-01

    Imagine creating a movie by excerpting scenes from "Dances With Wolves," splicing it with footage from "Code 3" or "Emergency Response" and then flavoring the script with the mystery of a Tony Hillerman novel. A film producer would probably find it quite difficult to choreograph a finished product from such a compilation of material. To hundreds of Native American EMS providers, however, such a movie is played out every day in Indian country. And with this movie come some real-life problems, including trauma, which is the number-one cause of premature death among Native Americans. But a high trauma rate is just one of the challenges facing tribal EMS responders. There's also prolonged response and transport, the problems involved in maintaining the unique culture and standard of care, the challenges of tribal EMS administration and EMS education of Native American students, and the unsure future of Native American EMS. Beyond that, there's the fact that EMS is a s unique to each Indian reservation as are the cultures of the native peoples who reside on these lands. Yet while no two systems are alike, most tribal EMS providers face similar challenges.

  17. MASIC: a software program for fast quantitation and flexible visualization of chromatographic profiles from detected LC-MS(/MS) features

    SciTech Connect

    Monroe, Matthew E.; Shaw, Jason L.; Daly, Don S.; Adkins, Joshua N.; Smith, Richard D.

    2008-06-01

    Quantitative analysis of liquid chromatography (LC)- mass spectrometry (MS) and tandem mass spectrometry (MS/MS) data is essential to many proteomics studies. We have developed MASIC to accurately measure peptide abundances and LC elution times in low-resolution LC-MS/MS analyses. This software program uses an efficient processing algorithm to quickly generate mass specific selected ion chromatograms from a dataset and provides an interactive browser that allows users to examine individual chromatograms in a variety of fashions. The improved elution time estimates afforded by MASIC increase the utility of LC-MS/MS data in the accurate mass and time (AMT) tag approach to proteomics.

  18. 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...

  19. High-throughput GC/MS and HPLC/MS/MS techniques for the multiclass, multiresidue determination of 653 pesticides and chemical pollutants in tea.

    PubMed

    Pang, Guo-Fang; Fan, Chun-Lin; Zhang, Feng; Li, Yan; Chang, Qiao-Ying; Cao, Yan-Zhong; Liu, Yong-Ming; Li, Zeng-Yin; Wang, Qun-Jie; Hu, Xue-Yan; Liang, Ping

    2011-01-01

    An efficient and sensitive method has been established for simultaneous determination of 653 pesticides in teas by GC/MS and HPLC/MS/MS. The method involved extraction with acetonitrile followed by cleanup using Cleanert-TPT SPE and subsequent identification and quantitation of 490 pesticides by GC/MS and 448 pesticides by HPLC/MS/ MS. The LODs for pesticides determined by GC/MS were between 1.0 and 500 microg/kg, and those determined by HPLC/MS/MS were between 0.03 and 4820 microg/kg. At the low fortification levels of 0.01-100 microg/kg, the average recoveries of 94% of the pesticides determined by GC/MS were between 60 and 120%, 77% of which had an RSD below 20%. For 91% of pesticides determined by HPLC/MS/MS, the average recoveries were between 60 and 120%, 76% of which had an RSD below 20%. The paper also reports a novel SPE column, Cleanert TPT, which comprised graphitized carbon black (PestiCarb), polyamine silica, and amide polystyrene for purifying the tea samples. The results indicated good repeatiblity and reproducibility.

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

    SciTech Connect

    Owens, J; Vu, A; Koester, C

    2008-10-31

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

  1. Glyco- and sphingophosphonolipids from the medusa Phyllorhiza punctata: NMR and ESI-MS/MS fingerprints.

    PubMed

    de Souza, Lauro M; Iacomini, Marcello; Gorin, Philip A J; Sari, Roger S; Haddad, Maria A; Sassaki, Guilherme L

    2007-02-01

    The medusa Phyllorhiza punctata has been found in Brazilian waters where it is an exotic species, having arrived in ballasts from the Indo-Pacific Ocean in the general region of North Australia and Indonesia. Fatty acids of the intact animal and its component umbrella, oral arms, and mucus were identified. Two different groups of glycolipids and a sphingolipid were isolated by silica-gel column chromatography and characterized using GC-MS, ESI-MS, 1D, 2D (13)C, (1)H and (31)P NMR spectroscopy. They were sulfoquinovosyldiacylglycerol (SQDG), monogalactosyldiacylglycerol (MGDG), and ceramide aminoethylphosphonate (CAEP). The CAEP long chain base (LCB) and its polar head group (PHG) formed by partial hydrolysis, were analyzed by ESI-MS/MS. The probable origin of MGDG and SQDG in the jellyfish is the result of an endosymbiotic association with a microalga of the Dinoflagellate group, since these lipids are commonly found in photosynthetic membranes.

  2. Characterization of phenolic composition in Lamiaceae spices by LC-ESI-MS/MS.

    PubMed

    Hossain, Mohammad B; Rai, Dilip K; Brunton, Nigel P; Martin-Diana, Ana B; Barry-Ryan, Catherine

    2010-10-13

    A total of 38 phenolic compounds in the solid/liquid extracts of five Lamiaceae spices, rosemary, oregano, sage, basil, and thyme, were identified in the present study using LC-ESI-MS/MS. These compounds were distributed in four major categories, namely, hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, flavonoids, and phenolic terpenes. Among them, the category of flavonoids was the largest, with 17 compounds. Identification of the phenolic compounds was carried out by comparing retention times and mass spectra with those of authentic standards. If standards were unavailable, phenolic compounds were identified on the basis of accurate mass of pseudomolecular [M - H](-) ions and tandem mass spectrometry (MS/MS) data. The results of accurate mass measurements fit well with the elemental composition of the compounds. The diagnostic fragmentation patterns of the compounds during collision-induced dissociation (CID) elucidated the structural information of the compounds analyzed.

  3. MS fragment isotope ratio analysis for evaluation of citrus essential oils by HRGC-MS.

    PubMed

    Satake, Atsushi; Furukawa, Kiyoshi; Ueno, Takao; Ukeda, Hiroyuki; Sawamura, Masayoshi

    2004-02-01

    To evaluate the origin of citrus essential oils, the isotope ratio of fragment peaks on HRGC-MS of the volatile compounds from various citrus oils was measured. The MS fragment ratio was found by the ratio of fragment peak intensity, m+1/m (m/z). This ratio reflects the isotope effect of volatile compounds, that is, it provides information about locality, quality, and species for essential oils. Multivariate analysis based on the MS fragment ratio of monoterpene hydrocarbons clearly distinguished three citrus species, yuzu, lemon, and lime. The carbonyl fractions were also extracted from citrus essential oils by the sodium hydrogensulfite method. The isotope ratio of MS fragments of octanal, nonanal, and decanal was also examined. The results suggest that there was no significant difference in the individual fragment isotope ratios of the three aldehydes.

  4. Quantification of Free Carnitine and Acylcarnitines in Plasma or Serum Using HPLC/MS/MS.

    PubMed

    Scott, David; Heese, Bryce; Garg, Uttam

    2016-01-01

    Acylcarnitines are formed by esterification between fatty acids CoA or organic acids CoA molecules and carnitine. In various fatty acids oxidation defects and organic acidurias, there is increased concentration of corresponding acylcarnitines. Abnormalities in specific acylcarnitines are used in the diagnosis of fatty acids oxidation defects and organic acidurias. Most commonly used method for the assay of acylcarnitines is HPLC-tandem mass spectrometry (HPLC/MS/MS). A HPLC/MS/MS method is described for the quantification of number of acylcarnitines. The method involves butylation of carnitine/acylcarnitines using acidified butanol, HPLC flow injection, and measurement of acylcarnitines using precursor ion scan and multiple reactions monitoring (MRM).

  5. Measurement of free carnitine and acylcarnitines in plasma by HILIC-ESI-MS/MS without derivatization.

    PubMed

    Peng, Minzhi; Liu, Li; Jiang, Minyan; Liang, Cuili; Zhao, Xiaoyuan; Cai, Yanna; Sheng, Huiying; Ou, Zhiying; Luo, Hong

    2013-08-01

    Measurement of carnitine and acylcarnitines in plasma is important in diagnosis of fatty acid β-oxidation disorders and organic acidemia. The usual method uses flow injection tandem mass spectrometry (FIA-MS/MS), which has limitations. A rapid and more accurate method was developed to be used for high-risk screening and diagnosis. Carnitine and acylcarnitines were separated by hydrophilic interaction liquid chromatography (HILIC) without derivatization and detected with a QTRAP MS/MS System. Total analysis time was 9.0min. The imprecision of within- and between-run were less than 6% and 17%, respectively. Recoveries were in the range of 85-110% at three concentrations. Some acylcarnitine isomers could be separated, such as dicarboxylic and hydroxyl acylcarnitines. The method could also separate interferent to avoid false positive results. 216 normal samples and 116 patient samples were detected with the validated method, and 49 patients were identified with fatty acid oxidation disorders or organic acidemias.

  6. Development of LC-MS/MS analysis of cyclic dipeptides and its application to tea extract.

    PubMed

    Yamamoto, Kenji; Hayashi, Miki; Murakami, Yuka; Araki, Yoko; Otsuka, Yuuki; Kashiwagi, Takehiro; Shimamura, Tomoko; Ukeda, Hiroyuki

    2015-01-01

    2,5-Diketopiperazines (DKPs), also called cyclic dipeptides, have been known to occur in various foods. Recently, DKPs have attracted attentions as bioactive components. There were some reports on analytical methods for DKPs, but the number of analyzed DKPs was only a part of all DKPs and the quantitative performance was not studied in detail. In this study, we selected 31 kinds of DKPs and developed a quantitative and simultaneous analytical method using LC-MS/MS. This method was applied to DKPs determination in Pu-erh tea, post-fermentation tea, and 18 kinds of DKPs were determined at concentration of 0.0017-0.11 ppm. As a result of spiked test, it was concluded that the developed method using LC-MS/MS was useful for estimating DKPs concentration in tea.

  7. Determination of hydrogen cyanide in cigarette mainstream smoke by LC/MS/MS.

    PubMed

    Mottier, Nicolas; Jeanneret, Florent; Rotach, Michel

    2010-01-01

    An LC/MS/MS method is presented for the determination of hydrogen cyanide in cigarette mainstream smoke. Cyanide is derivatized with 2,3'-naphthalenedicarboxaldehyde and taurine to form a benzo[f]isoindole derivative, which is then analyzed by LC/MS/MS. Isotopic KCN (K13C15N) was used as an internal standard. The regression equation was linear within the range 2.4-331 ng/mL for cyanide with a correlation coefficient > 0.999. The LOD was calculated as 4.1 ng/cigarette. The influence of the sodium hydroxide trapping solution concentration on the results is discussed. A 1 M solution showed the best results in terms of sample stability and trapping efficiency. The method proved to be robust, reliable, and more selective than current methods, making it a logical choice for determination of total cyanide in cigarette smoke.

  8. [Simultaneous determination of pesticide residues in agricultural products by LC-MS/MS].

    PubMed

    Watanabe, Minae; Ueno, Eiji; Inoue, Tomomi; Ohno, Haruka; Ikai, Yoshitomo; Morishita, Toshio; Oshima, Harumi; Hayashi, Rumiko

    2013-01-01

    A method for the simultaneous determination of multiple pesticide residues in agricultural products was developed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The sample was extracted with acetonitrile. Co-extractives were removed by GPC/graphitized carbon column SPE, and silica gel/PSA cartridge column SPE. Pesticides in the test solution were determined by LC-MS/MS using scheduled MRM. Recoveries of 124 pesticides from spinach, brown rice, soybean, orange and tomato were tested at the level of 0.1 µg/g, and those of 121 pesticides ranged from 70 to 120% (RSD≤15%). Pesticide residues in 239 agricultural products were investigated by this method, and residues of 49 pesticides were detected in 98 agricultural products.

  9. The APEX Quantitative Proteomics Tool: Generating protein quantitation estimates from LC-MS/MS proteomics results

    PubMed Central

    Braisted, John C; Kuntumalla, Srilatha; Vogel, Christine; Marcotte, Edward M; Rodrigues, Alan R; Wang, Rong; Huang, Shih-Ting; Ferlanti, Erik S; Saeed, Alexander I; Fleischmann, Robert D; Peterson, Scott N; Pieper, Rembert

    2008-01-01

    Background Mass spectrometry (MS) based label-free protein quantitation has mainly focused on analysis of ion peak heights and peptide spectral counts. Most analyses of tandem mass spectrometry (MS/MS) data begin with an enzymatic digestion of a complex protein mixture to generate smaller peptides that can be separated and identified by an MS/MS instrument. Peptide spectral counting techniques attempt to quantify protein abundance by counting the number of detected tryptic peptides and their corresponding MS spectra. However, spectral counting is confounded by the fact that peptide physicochemical properties severely affect MS detection resulting in each peptide having a different detection probability. Lu et al. (2007) described a modified spectral counting technique, Absolute Protein Expression (APEX), which improves on basic spectral counting methods by including a correction factor for each protein (called Oi value) that accounts for variable peptide detection by MS techniques. The technique uses machine learning classification to derive peptide detection probabilities that are used to predict the number of tryptic peptides expected to be detected for one molecule of a particular protein (Oi). This predicted spectral count is compared to the protein's observed MS total spectral count during APEX computation of protein abundances. Results The APEX Quantitative Proteomics Tool, introduced here, is a free open source Java application that supports the APEX protein quantitation technique. The APEX tool uses data from standard tandem mass spectrometry proteomics experiments and provides computational support for APEX protein abundance quantitation through a set of graphical user interfaces that partition thparameter controls for the various processing tasks. The tool also provides a Z-score analysis for identification of significant differential protein expression, a utility to assess APEX classifier performance via cross validation, and a utility to merge multiple

  10. STS-33 MS Carter and MS Thornton display 'Maggot on Board' sign and candy

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Mission Specialist (MS) Manley L. Carter, Jr (left) and MS Kathryn C. Thornton display 'Maggot on Board' sign and 'SMARTIES' candy stored in plastic bag on the aft flight deck of Discovery, Orbiter Vehicle (OV) 103. The mission specialists are wearing their mission polo shirts and communications kit assembly headsets. An overhead window appears above their heads. A gold necklace chain floats around Carter's neck.

  11. STS-35 MS Hoffman's height is recorded by MS Lounge on OV-102's middeck

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-35 Mission Specialist (MS) Jeffrey A. Hoffman stretches out on the middeck floor while MS John M. Lounge records his height. The two crewmembers are in front of the forward lockers aboard Columbia, Orbiter Vehicle (OV) 102. Hoffman steadies himself using the stowed treadmill and the lockers. Above Hoffman's head is a plastic bag filled with Development Test Objective (DTO) 634, Trash Compaction and Retention System Demonstration, trash compactor charcoal filtered bag lids.

  12. Quantitation of Total Buprenorphine and Norbuprenorphine in Meconium by LC-MS/MS.

    PubMed

    Marin, Stephanie J; McMillin, Gwendolyn A

    2016-01-01

    Buprenorphine (Suboxone, Zubsolv, Buprenex, Butrans, etc.) is an opioid drug that has been used to treat opioid dependence on an outpatient basis, and is also prescribed for managing moderate to severe pain. Pregnant women may be prescribed buprenorphine as part of a treatment plan for opioid addiction. This chapter quantitates buprenorphine and norbuprenorphine in meconium by liquid chromatography tandem mass spectrometry (LC-MS/MS).

  13. Algorithms for database-dependent search of MS/MS data.

    PubMed

    Matthiesen, Rune

    2013-01-01

    The frequent used bottom-up strategy for identification of proteins and their associated modifications generate nowadays typically thousands of MS/MS spectra that normally are matched automatically against a protein sequence database. Search engines that take as input MS/MS spectra and a protein sequence database are referred as database-dependent search engines. Many programs both commercial and freely available exist for database-dependent search of MS/MS spectra and most of the programs have excellent user documentation. The aim here is therefore to outline the algorithm strategy behind different search engines rather than providing software user manuals. The process of database-dependent search can be divided into search strategy, peptide scoring, protein scoring, and finally protein inference. Most efforts in the literature have been put in to comparing results from different software rather than discussing the underlining algorithms. Such practical comparisons can be cluttered by suboptimal implementation and the observed differences are frequently caused by software parameters settings which have not been set proper to allow even comparison. In other words an algorithmic idea can still be worth considering even if the software implementation has been demonstrated to be suboptimal. The aim in this chapter is therefore to split the algorithms for database-dependent searching of MS/MS data into the above steps so that the different algorithmic ideas become more transparent and comparable. Most search engines provide good implementations of the first three data analysis steps mentioned above, whereas the final step of protein inference are much less developed for most search engines and is in many cases performed by an external software. The final part of this chapter illustrates how protein inference is built into the VEMS search engine and discusses a stand-alone program SIR for protein inference that can import a Mascot search result.

  14. STS-37 MS Godwin balances MS Ross using her index finger on OV-104's middeck

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-37 Mission Specialist (MS) Linda M. Godwin holds MS Jerry L. Ross over her head using only her index finger. The two crewmembers are participating in a microgravity balancing act on the middeck of Atlantis, Orbiter Vehicle (OV) 104. The Bioserve Instrumentation Technology Associates Materials Dispersion Apparatus (BIMDA) bioprocessing test bed mixing and sampling configuration is attached to the forward middeck lockers at Ross' right. The sleep restraints are attached on the starboard wall behind the astronauts.

  15. STS-47 MS Davis and MS/PLC Lee during JSC bailout training

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-47 Endeavour, Orbiter Vehicle (OV) 105, Mission Specialist (MS) N. Jan Davis (left) and MS and Payload Commander (PLC) Mark C. Lee take a break from bailout (launch egress training) held in JSC's Mockup and Training Laboratory (MAIL) Bldg 9A. The two crewmembers, wearing launch and entry suits (LESs) and communications carrier assemblies (CCAs), are standing in front of the crew compartment trainer (CCT).

  16. STS-35 MS Hoffman and MS Parker on the middeck of Columbia, OV-102

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Posing on the middeck of Columbia, Orbiter Vehicle (OV) 102, are Mission Specialist (MS) Jeffrey A. Hoffman (mustache) and MS Robert A. R. Parker. Determining who is right side up is complicated by the microgravity of space. Hoffman's head is at the middeck floor and his feet are at the ceiling. The two crewmembers are in front of OV-102's port side with the waste collection system (WCS) contingency unit, side hatch, and galley visible behind them.

  17. MS/MS analysis of the products of toluene photooxidation and measurement of their mutagenic activity

    SciTech Connect

    Dumdel, B.E.; Kenny, D.V.; Shepson, P.B.; Kleindienst, T.E.; Nero, C.M.; Cupitt, L.T.; Claxton, L.D.

    1988-12-01

    Products of the photooxidation of toluene from an irradiated 5.1 ppm toluene/0.9 ppm NO/sub x/ mixture were identified by use of a triple-quadrupole MS/MS operated in an atmospheric pressure ionization mode. The reaction was carried out in a flow-mode 22.7-m/sup 3/ Telfon smog chamber. The steady-state reactant and product mixture was continuously transferred to the mass spectrometer inlet at 144 L/min. By using structurally similar standards, semiquantitative MS/MS analyses for many of the ring fragmentation products were conducted. Quantitative analyses by chromatographic methods and semiquantitative analyses by MS/MS were conducted for a variety of ring fragmentation products. The following products were found with yields of 1% (C/C) or greater: methylglyoxal, glyoxal, benzaldehyde, methylbutenedial, hydroxy-methylbutenedial, peroxyacetyl nitrate, oxoheptadienal, CH/sub 3/COOH, HCHO, hexadienal, and hydroxyoxo-heptadienal. The mutagenic activity of the steady-state product mixture was measured by using the Ames assay Salmonella typhimurium strain TA 100. The mutagenic activity data are discussed relative to our earlier findings that resulted from different reaction conditions.

  18. Quantitative LC-MS/MS Analysis of Proteins Involved in Metastasis of Breast Cancer

    PubMed Central

    Goto, Rieko; Nakamura, Yasushi; Takami, Tomonori; Sanke, Tokio; Tozuka, Zenzaburo

    2015-01-01

    The purpose of this study was to develop quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for the analysis of proteins involved in metastasis of breast cancer for diagnosis and determining disease prognosis, as well as to further our understand of metastatic mechanisms. We have previously demonstrated that the protein type XIV collagen may be specifically expressed in metastatic tissues by two dimensional LC-MS/MS. In this study, we developed quantitative LC-MS/MS methods for type XIV collagen. Type XIV collagen was quantified by analyzing 2 peptides generated by digesting type XIV collagen using stable isotope-labeled peptides. The individual concentrations were equivalent between 2 different peptides of type XIV collagen by evaluation of imprecise transitions and using the best transition for the peptide concentration. The results indicated that type XIV collagen is highly expressed in metastatic tissues of patients with massive lymph node involvement compared to non-metastatic tissues. These findings were validated by quantitative real-time RT-PCR. Further studies on type XIV collagen are desired to verify its role as a prognostic factor and diagnosis marker for metastasis. PMID:26176947

  19. Analysis of coffee for the presence of acrylamide by LC-MS/MS.

    PubMed

    Andrzejewski, Denis; Roach, John A G; Gay, Martha L; Musser, Steven M

    2004-04-07

    A variety of popular instant, ground, and brewed coffees were analyzed using a modified liquid chromatography-tandem mass spectrometry (LC-MS/MS) method specifically developed for the determination of acrylamide in foods. Coffee test portions were spiked with 13C3-labeled acrylamide as an internal standard prior to their extraction and cleanup. Ground coffees (1 g) and instant coffees (0.5 g) were extracted by shaking with 9 mL of water for 20 min. Brewed coffee test portions (9 mL) were taken through the cleanup procedure without further dilution with extraction solvent. Coffee test portions were cleaned up by passing 1.5 mL first through an Oasis HLB (hydrophilic/lipophilic copolymer sorbent) solid phase extraction (SPE) cartridge and then a Bond Elut-Accucat (cation and anion exchange sorbent) SPE cartridge. The cleaned up extracts were analyzed by positive ion electrospray LC-MS/MS. The MS/MS data was used to detect, confirm, and quantitate acrylamide. The limit of quantitation of the method was 10 ng/g for ground and instant coffees and 1.0 ng/mL for brewed coffee. The levels of acrylamide ranged from 45 to 374 ng/g in unbrewed coffee grounds, from 172 to 539 ng/g in instant coffee crystals, and from 6 to 16 ng/mL in brewed coffee.

  20. Determination of buprenorphine, fentanyl and LSD in whole blood by UPLC-MS-MS.

    PubMed

    Berg, Thomas; Jørgenrud, Benedicte; Strand, Dag Helge

    2013-04-01

    A sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method has been developed and validated for the quantification of buprenorphine, fentanyl and lysergic acid diethylamide (LSD) in whole blood. Sample preparation was performed by liquid-liquid extraction (LLE) with methyl tert-butyl ether. UPLC-MS-MS analysis was performed with a mobile phase consisting of ammonium formate (pH 10.2) and methanol. Positive electrospray ionization MS-MS detection was performed with two multiple reaction monitoring transitions for each of the analytes and the deuterium labeled internal standards. Limit of detection values of buprenorphine, fentanyl and LSD were 0.28, 0.044 and 0.0097 ng/mL and limit of quantification values were 0.94, 0.14 and 0.036 ng/mL, respectively. Most phospholipids were removed during LLE. No or only minor matrix effects were observed. The method has been routinely used at the Norwegian Institute of Public Health since September 2011 for qualitative and quantitative detections of buprenorphine, fentanyl and/or LSD in more than 400 whole blood samples with two replicates per sample.

  1. Determination and pharmacokinetics of amygdalin in rats by LC-MS-MS.

    PubMed

    Li, Xiao-bo; Liu, Chang-hui; Zhang, Rong; Huang, Xiao-tao; Li, Ying-yi; Han, Liang; Xu, Mei-li; Mi, Sui-qing; Wang, Ning-sheng

    2014-07-01

    A sensitive and specific liquid chromatography-tandem mass spectrometric (LC-MS-MS) method was developed for the determination and pharmacokinetics of amygdalin in rats. Rat plasma pretreated by solid-phase extraction was analyzed by LC-MS-MS with negative electrospray ionization in the multiple reaction monitoring mode. Amygdalin and geniposide [the internal standard (IS)] were separated on a C18 column eluted with a mobile phase of methanol and water (85:15; v/v) at a flow rate of 0.25 mL/min in a run time of 3.0 min. The precursor to product ion transitions were monitored at m/z 457.2 → 279.1 for amygdalin and m/z 387.1 → 224.9 for the IS. The calibration curve of amygdalin showed good linearity over a concentration range of 10-2,000 ng/mL. The limit of quantification was 10 ng/mL. Intra-day and inter-day precisions and accuracy (percent relative standard deviation) were both within 10%. The method was fully validated for its selectivity, sensitivity, matrix effect, recovery and stability. This accurate and specific assay produced a useful LC-MS-MS method, which was successfully applied to pharmacokinetic studies after the oral administration of amygdalin to rats.

  2. Identification of RNA sequence isomer by isotope labeling and LC-MS/MS.

    PubMed

    Li, Siwei; Limbach, Patrick A

    2014-11-01

    Recently, we developed a method for modified ribonucleic acid (RNA) analysis based on the comparative analysis of RNA digests (CARD). Within this CARD approach, sequence or modification differences between two samples are identified through differential isotopic labeling of two samples. Components present in both samples will each be labeled, yielding doublets in the CARD mass spectrum. Components unique to only one sample should be detected as singlets. A limitation of the prior singlet identification strategy occurs when the two samples contain components of unique sequence but identical base composition. At the first stage of mass spectrometry, these sequence isomers cannot be differentiated and would appear as doublets rather than singlets. However, underlying sequence differences should be detectable by collision-induced dissociation tandem mass spectrometry (CID MS/MS), as y-type product ions will retain the original enzymatically incorporated isotope label. Here, we determine appropriate instrumental conditions that enable CID MS/MS of isotopically labeled ribonuclease T1 (RNase T1) digestion products such that the original isotope label is maintained in the product ion mass spectrum. Next, we demonstrate how y-type product ions can be used to differentiate singlets and doublets from isomer sequences. We were then able to extend the utility of this approach by using CID MS/MS for the confirmation of an expected RNase T1 digestion product within the CARD analysis of an Escherichia coli mutant strain even in the presence of interfering and overlapping digestion products from other transfer RNAs.

  3. Stable Isotope Labeled Tracers for Metabolic Pathway Elucidation by GC-MS and FT-MS

    PubMed Central

    Higashi, Richard M.; Fan, Teresa W-M.; Lorkiewicz, Pawel K.; Moseley, Hunter N.B.; Lane, Andrew N.

    2015-01-01

    Advances in analytical methodologies, principally nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS), over the last decade have made large-scale analysis of the human metabolome a reality. This is leading to the reawakening of the importance of metabolism in human diseases, particularly widespread metabolic diseases such as cancer, diabetes, and obesity. Emerging NMR and MS atom-tracking technologies and informatics is poised to revolutionize metabolomics-based research because they deliver the high information throughput (HIT) that is needed for deciphering systems biochemistry. In particular, Stable Isotope Resolved Metabolomics (SIRM) enables unambiguous tracking of individual atoms through compartmentalized metabolic networks, in a wide range of experimental systems, including human subjects. MS offers a wide range of initial capital outlay and operating costs, ranging from gas-chromatography (GC) MS affordable by many individual laboratories, to the HIT-supporting Fourier-transform (FT) class of MS that rivals NMR in cost and infrastructure support. This chapter will focus on sample preparation, instrument, and data processing procedures for these two extremes of MS instrumentation used in SIRM. PMID:25270929

  4. Confirmation of Drug Delivery after Liver Chemoembolization: Direct Tissue Doxorubicin Measurement by UHPLC-MS-MS

    PubMed Central

    Baumgarten, Sigrid; Gaba, Ron C.; van Breemen, Richard B.

    2012-01-01

    Because liver cancer is rarely suitable for surgery, transcatheter arterial chemoembolization (TACE) is used for palliative therapy. In this procedure, an emulsion of doxorubicin in iodized oil is injected directly into liver tumors through a catheter positioned within the artery supplying blood flow to the tumor. At present, there is limited understanding of factors affecting the delivery and dispersion of doxorubicin within treated tumors during TACE. This study addresses the development and application of an ultrahigh pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) method for rapid confirmation of drug delivery after TACE in a rabbit VX2 liver cancer model. Doxorubicin levels in liver tumors were measured using UHPLC-MS-MS and compared with computed tomography measured levels of iodized oil, a metric used clinically to indicate drug delivery. We found that tissue drug levels determined using UHPLC-MS-MS did not correlate with the regional iodized oil concentration (vehicle) within tumors following TACE, suggesting that chemotherapeutic drugs like doxorubicin spread throughout tumors, and that lack of iodized oil staining in portions of a tumor does not necessarily indicate inadequate therapy during TACE. PMID:22454282

  5. Ultrahigh-throughput proteomics using fast RPLC separations with ESI-MS/MS.

    PubMed

    Shen, Yufeng; Smith, Richard D; Unger, Klaus K; Kumar, Dipika; Lubda, Dieter

    2005-10-15

    We describe approaches for proteomics analysis using electrospray ionization-tandem mass spectrometry coupled with fast reversed-phase liquid chromatography (RPLC) separations. The RPLC separations used 50-microm-i.d. fused-silica capillaries packed with submicrometer-sized C18-bonded porous silica particles and achieved peak capacities of 130-420 for analytes from proteome tryptic digests. When these separations were combined with linear ion trap tandem mass spectrometry measurements, approximately 1000 proteins could be identified in 50 min from approximately 4000 identified tryptic peptides; approximately 550 proteins in 20 min from approximately 1800 peptides; and approximately 250 proteins in 8 min from approximately 700 peptides for a S. oneidensis tryptic digest. The dynamic range for protein identification with the fast separations was determined to be approximately 3-4 orders of magnitude of relative protein abundance on the basis of known proteins in human blood plasma analyses. We found that 55% of the MS/MS spectra acquired during the entire analysis (and up to 100% of the MS/MS spectra acquired from the most data-rich zone) provided sufficient quality for identifying peptides. The results confirm that such analyses using very fast (minutes) RPLC separations based on columns packed with microsized porous particles are primarily limited by the MS/MS analysis speed.

  6. [Potential pathogens in multiple sclerosis (MS)].

    PubMed

    Zawada, Mariola

    2012-10-22

     Multiple sclerosis is a neuroimmunological disease in which etiologic agents have not been identified yet. The etiology of MS is complex in its nature and may involve many different agents acting simultaneously or in a cascade manner leading to the development of the disease. The causes of MS development were sought among the factors associated with HLA and TCR genes and human endogenous retroviruses (HERV). Environmental factors such as bacterial, fungal and viral infections as well as potential participation of vitamin D in the pathogenesis of the disease have also been examined. The current state of knowledge concerning potential factors participating in the etiopathogenesis of multiple sclerosis has been reviewed in this paper.

  7. Greenhouse Gas Analysis by GC/MS

    NASA Astrophysics Data System (ADS)

    Bock, E. M.; Easton, Z. M.; Macek, P.

    2015-12-01

    Current methods to analyze greenhouse gases rely on designated complex, multiple-column, multiple-detector gas chromatographs. A novel method was developed in partnership with Shimadzu for simultaneous quantification of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in environmental gas samples. Gas bulbs were used to make custom standard mixtures by injecting small volumes of pure analyte into the nitrogen-filled bulb. Resulting calibration curves were validated using a certified gas standard. The use of GC/MS systems to perform this analysis has the potential to move the analysis of greenhouse gasses from expensive, custom GC systems to standard single-quadrupole GC/MS systems that are available in most laboratories, which wide variety of applications beyond greenhouse gas analysis. Additionally, use of mass spectrometry can provide confirmation of identity of target analytes, and will assist in the identification of unknown peaks should they be present in the chromatogram.

  8. Isotopic ratio measurements with ICP-MS

    SciTech Connect

    Russ, G.P. III; Bazan, J.M.

    1986-06-03

    An inductively-coupled-plasma source mass spectrometer (ICP-MS) has been used to measure the isotopic composition of U, Pb, Os, and B standards. Particular emphasis has been placed on uranium because of its nuclear and environmental interest and because of the availability of a well-characterized set of standards with a wide range of isotopic compositions. The precision and accuracy obtainable in isotope ratio measurements by ICP-MS depend on many factors including background, interferences, dead time, mass fractionation (bias), abundance sensitivity, and counting statistics. Which, if any, of these factors controls accuracy and precision depends on the type of sample being analyzed and the characteristics of the mass spectrometer. These issues are discussed in detail.

  9. Familiar Face Detection in 180ms

    PubMed Central

    Visconti di Oleggio Castello, Matteo; Gobbini, M. Ida

    2015-01-01

    The visual system is tuned for rapid detection of faces, with the fastest choice saccade to a face at 100ms. Familiar faces have a more robust representation than do unfamiliar faces, and are detected faster in the absence of awareness and with reduced attentional resources. Faces of family and close friends become familiar over a protracted period involving learning the unique visual appearance, including a view-invariant representation, as well as person knowledge. We investigated the effect of personal familiarity on the earliest stages of face processing by using a saccadic-choice task to measure how fast familiar face detection can happen. Subjects made correct and reliable saccades to familiar faces when unfamiliar faces were distractors at 180ms—very rapid saccades that are 30 to 70ms earlier than the earliest evoked potential modulated by familiarity. By contrast, accuracy of saccades to unfamiliar faces with familiar faces as distractors did not exceed chance. Saccades to faces with object distractors were even faster (110 to 120 ms) and equivalent for familiar and unfamiliar faces, indicating that familiarity does not affect ultra-rapid saccades. We propose that detectors of diagnostic facial features for familiar faces develop in visual cortices through learning and allow rapid detection that precedes explicit recognition of identity. PMID:26305788

  10. Detection of gamma-hydroxybutyrate in hair: validation of GC-MS and LC-MS/MS methods and application to a real case.

    PubMed

    Bertol, Elisabetta; Argo, Antonina; Procaccianti, Paolo; Vaiano, Fabio; Di Milia, Maria Grazia; Furlanetto, Sandra; Mari, Francesco

    2012-11-01

    A gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method were validated for quantifying endogenous and exogenous hair concentrations of gamma-hydroxybutyrate (GHB). The GC-MS method is based on overnight extraction of 25 mg hair in NaOH at 56 °C, liquid/liquid extraction in ethylacetate and trimethylsylil derivatization; analysis is by electron ionization and single ion monitoring of three ions. The LC-MS/MS method entails a rapid digestion of 25 mg hair with NaOH at 75 °C for 40 min, liquid/liquid extraction in ethylacetate and reconstitution of the extract in the LC mobile phase; negative ion electrospray ionization and multiple reaction monitoring (MRM) analysis are employed for the LC-MS/MS detection. In both cases, GHB-d6 is used as an internal standard. The endogenous amount in "blank" hair are estimated by the standard addition method. Limits of detection are 0.4 and 0.5 ng/mg for GC-MS and LC-MS/MS respectively, while the limit of quantification (LOQ) is 0.6 ng/mg for both methods; the GC-MS method proved to be linear in the range 1-50 ng/mg whereas linearity was demonstrated from 0.6 to 50 ng/mg for the LC-MS/MS; imprecision and inaccuracy were always lower than 23% for quality controls samples. The two methods were applied to a real case of a man addicted to GHB; the drug concentration in segments from 17 cm hair strand well correlated with self-reported use of GHB in different periods of his life. Performances of the two methods were similar.

  11. siMS Score: Simple Method for Quantifying Metabolic Syndrome

    PubMed Central

    Soldatovic, Ivan; Vukovic, Rade; Culafic, Djordje; Gajic, Milan; Dimitrijevic-Sreckovic, Vesna

    2016-01-01

    Objective To evaluate siMS score and siMS risk score, novel continuous metabolic syndrome scores as methods for quantification of metabolic status and risk. Materials and Methods Developed siMS score was calculated using formula: siMS score = 2*Waist/Height + Gly/5.6 + Tg/1.7 + TAsystolic/130—HDL/1.02 or 1.28 (for male or female subjects, respectively). siMS risk score was calculated using formula: siMS risk score = siMS score * age/45 or 50 (for male or female subjects, respectively) * family history of cardio/cerebro-vascular events (event = 1.2, no event = 1). A sample of 528 obese and non-obese participants was used to validate siMS score and siMS risk score. Scores calculated as sum of z-scores (each component of metabolic syndrome regressed with age and gender) and sum of scores derived from principal component analysis (PCA) were used for evaluation of siMS score. Variants were made by replacing glucose with HOMA in calculations. Framingham score was used for evaluation of siMS risk score. Results Correlation between siMS score with sum of z-scores and weighted sum of factors of PCA was high (r = 0.866 and r = 0.822, respectively). Correlation between siMS risk score and log transformed Framingham score was medium to high for age groups 18+,30+ and 35+ (0.835, 0.707 and 0.667, respectively). Conclusions siMS score and siMS risk score showed high correlation with more complex scores. Demonstrated accuracy together with superior simplicity and the ability to evaluate and follow-up individual patients makes siMS and siMS risk scores very convenient for use in clinical practice and research as well. PMID:26745635

  12. Validation of an HPLC-MS/MS and wipe procedure for mitomycin C contamination.

    PubMed

    B'Hymer, Clayton; Connor, Thomas; Stinson, Derek; Pretty, Jack

    2015-04-01

    A high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the determination of mitomycin C, an anticancer drug, from contamination on various surfaces. Mitomycin C is often used in various forms of intraperitoneal chemotherapy, and operating room healthcare worker exposure to this drug is possible. The surface testing method consisted of a wiping procedure utilizing a solution of 20/45/35 (v/v/v) of acetonitrile-isopropanol-water made 0.01 M in ammonium citrate (apparent pH 7.0). The wipe solutions were analyzed by means of HPLC-MS/MS using a reversed-phase gradient system and electrospray ionization in positive ion mode with a triple-quadrupole MS detector. Accuracy and precision of this method were demonstrated by a series of recovery studies of both spiked solutions and extracted wipes from various surfaces (stainless steel, vinyl and Formica(®)) spiked with known levels of mitomycin C. Recoveries of spiked solutions containing the analyte demonstrate mean recoveries (accuracy) ranged from 93 to 105%. Precision as measured by the relative standard deviation (% RSD) of multiple samples (n= 10) at each concentration level demonstrated values of 7.5% or less. The recoveries from spiked surfaces varied from 30 to 99%. The limit of detection for this methodology is ∼2 ng/100 cm(2) equivalent surface area, and the limit of quantitation is ∼6 ng/100 cm(2).

  13. LC-MS/MS method for the characterization of the forced degradation products of Entecavir.

    PubMed

    Ramesh, Thippani; Rao, Pothuraju Nageswara; Rao, Ramisetti Nageswara

    2014-02-01

    A rapid, specific, and reliable isocratic LC-MS/MS method has been developed and validated for the identification and characterization of the stressed degradation products of Entecavir (ETV). ETV, an antiviral drug, was subjected to hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis and thermal stress, as per the international conference on harmonization specified conditions. The drug showed extensive degradation under oxidative and acid hydrolysis stress conditions. However, it was stable to thermal, acidic, neutral, and photolysis stress conditions. A total of five degradation products were observed and the chromatographic separation of the drug and its degradation products were achieved on a Waters Symmetry C18 (250 mm × 4.6 mm, id, 5 μm) column using 20 mM ammonium acetate (pH 3)/acetonitrile (50:50, v/v) as a mobile phase. The degradation products were characterized by LC-MS/MS and its fragmentation pathways were proposed. The LC-MS method was validated with respect to specificity, linearity, accuracy, and precision. No previous reports were found in the literature regarding the degradation behavior of ETV.

  14. Comparison of Proteins in Whole Blood and Dried Blood Spot Samples by LC/MS/MS

    NASA Astrophysics Data System (ADS)

    Chambers, Andrew G.; Percy, Andrew J.; Hardie, Darryl B.; Borchers, Christoph H.

    2013-09-01

    Dried blood spot (DBS) sampling methods are desirable for population-wide biomarker screening programs because of their ease of collection, transportation, and storage. Immunoassays are traditionally used to quantify endogenous proteins in these samples but require a separate assay for each protein. Recently, targeted mass spectrometry (MS) has been proposed for generating highly-multiplexed assays for biomarker proteins in DBS samples. In this work, we report the first comparison of proteins in whole blood and DBS samples using an untargeted MS approach. The average number of proteins identified in undepleted whole blood and DBS samples by liquid chromatography (LC)/MS/MS was 223 and 253, respectively. Protein identification repeatability was between 77 %-92 % within replicates and the majority of these repeated proteins (70 %) were observed in both sample formats. Proteins exclusively identified in the liquid or dried fluid spot format were unbiased based on their molecular weight, isoelectric point, aliphatic index, and grand average hydrophobicity. In addition, we extended this comparison to include proteins in matching plasma and serum samples with their dried fluid spot equivalents, dried plasma spot (DPS), and dried serum spot (DSS). This work begins to define the accessibility of endogenous proteins in dried fluid spot samples for analysis by MS and is useful in evaluating the scope of this new approach.

  15. 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.

  16. Characterization of cocoa liquors by GC-MS and LC-MS/MS: focus on alkylpyrazines and flavanols.

    PubMed

    Magi, Emanuele; Bono, Luca; Di Carro, Marina

    2012-09-01

    Flavor is one of the most important characteristics of chocolate products and is due to a complex volatile fraction, depending both on the cocoa bean genotype and the several processes occurring during chocolate production (fermentation, drying, roasting and conching). Alkylpyrazines are among the most studied volatiles, being one of the main classes of odorant compounds in cocoa products. In this work, a mass spectrometric approach was used for the comparison of cocoa liquors from different countries. A headspace solid-phase microextraction gas chromatography-mass spectrometry method was developed for the qualitative study of the volatile fraction; the standard addition method was then used for the quantitative determination of five pyrazines (2-methylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine and tetramethylpyrazine). Satisfactory figures of merit were obtained: Limits of quantitation were in the range 0.1-2.7 ng/g; repeatability and reproducibility varied between 3% and 7% and between 8% and 14%, respectively. The total content of the pyrazines was remarkably different in the considered samples, ranging from 99 to 708 ng/g. Tetramethylpyrazine showed the highest concentration in all samples, with a maximum value of 585 ng/g. A preliminary study was also performed on the nonvolatile fraction using LC-MS/MS, identifying some flavanols such as catechin, epicatechin and procyanidins.

  17. 8. OLD AMORYBIGBEE BRIDGE MISSISSIPPI, MONROE CO., AMORY MS. 6, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. OLD AMORY-BIGBEE BRIDGE MISSISSIPPI, MONROE CO., AMORY MS. 6, 1.5 mi. NW of Amory. Road 2.5 mi. N of Bull Mtn. Cr. Copy of 8x10 photo taken at completion of work, 1899. Swing bridge is fully open. View from S. Credit to Evans Memorial Library, Aberdeen, Ms. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  18. 7. OLD AMORYBIGBEE BRIDGE MISSISSIPPI, MONROE CO., AMORY MS. 6, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. OLD AMORY-BIGBEE BRIDGE MISSISSIPPI, MONROE CO., AMORY MS. 6, 1.5 mi. NW of Amory. Road 2.5 mi. N of Bull Mtn. Cr. Copy of 8x10 photo taken at completion of work, 1899. Swing bridge is fully open. View from S. Credit to Evans Memorial Library, Aberdeen, Ms. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  19. Clinically meaningful performance benchmarks in MS

    PubMed Central

    Motl, Robert W.; Scagnelli, John; Pula, John H.; Sosnoff, Jacob J.; Cadavid, Diego

    2013-01-01

    Objective: Identify and validate clinically meaningful Timed 25-Foot Walk (T25FW) performance benchmarks in individuals living with multiple sclerosis (MS). Methods: Cross-sectional study of 159 MS patients first identified candidate T25FW benchmarks. To characterize the clinical meaningfulness of T25FW benchmarks, we ascertained their relationships to real-life anchors, functional independence, and physiologic measurements of gait and disease progression. Candidate T25FW benchmarks were then prospectively validated in 95 subjects using 13 measures of ambulation and cognition, patient-reported outcomes, and optical coherence tomography. Results: T25FW of 6 to 7.99 seconds was associated with a change in occupation due to MS, occupational disability, walking with a cane, and needing “some help” with instrumental activities of daily living; T25FW ≥8 seconds was associated with collecting Supplemental Security Income and government health care, walking with a walker, and inability to do instrumental activities of daily living. During prospective benchmark validation, we trichotomized data by T25FW benchmarks (<6 seconds, 6–7.99 seconds, and ≥8 seconds) and found group main effects on 12 of 13 objective and subjective measures (p < 0.05). Conclusions: Using a cross-sectional design, we identified 2 clinically meaningful T25FW benchmarks of ≥6 seconds (6–7.99) and ≥8 seconds. Longitudinal and larger studies are needed to confirm the clinical utility and relevance of these proposed T25FW benchmarks and to parse out whether there are additional benchmarks in the lower (<6 seconds) and higher (>10 seconds) ranges of performance. PMID:24174581

  20. A emissão em 8mm e as bandas de Merrill-Sanford em estrelas carbonadas

    NASA Astrophysics Data System (ADS)

    de Mello, A. B.; Lorenz-Martins, S.

    2003-08-01

    Estrelas carbonadas possuem bandas moleculares em absorção no visível e, no infravermelho (IR) as principais características espectrais se devem a emissão de grãos. Recentemente foi detectada a presença de bandas de SiC2 (Merrill-Sanford, MS) em emissão sendo atribuída à presença de um disco rico em poeira. Neste trabalho analisamos uma amostra de 14 estrelas carbonadas, observadas no telescópio de 1.52 m do ESO em 4 regiões espectrais diferentes, a fim de detectar as bandas de MS em emissão. Nossa amostra é composta de estrelas que apresentam além da emissão em 11.3 mm, outra em 8 mm. Esta última emissão, não usual nestes objetos, tem sido atribuída ou a moléculas de C2H2, ou a um composto sólido ainda indefinido. A detecção de emissões de MS e aquelas no IR, simultaneamente, revelaria um cenário mais complexo que o habitualmente esperado para os ventos destes objetos. No entanto como primeiro resultado, verificamos que as bandas de Merrill-Sanford encontram-se em absorção, não revelando nenhuma conexão com a emissão a 8 mm. Assim, temos duas hipóteses: (a) a emissão a 8 mm se deve à molécula C2H2 ou (b) essa emissão é resultado da emissão térmica de grãos. Testamos a segunda hipótese modelando a amostra com grãos não-homogêneos de SiC e quartzo, o qual emite em aproximadamente 8mm. Este grão seria produzido em uma fase evolutiva anterior a das carbonadas (estrelas S) e por terem uma estrutura cristalina são destruídos apenas na presença de campos de radiação ultravioleta muito intensos. Os modelos para os envoltórios utilizam o método de Monte Carlo para descrever o problema do transporte da radiação. As conclusões deste trabalho são: (1) as bandas de Merrill-Sanford se encontram em absorção, sugerindo um cenário usual para os ventos das estrelas da amostra; (2) neste cenário, a emissão em 8 mm seria resultado de grãos de quartzo com mantos de SiC, indicando que o quartzo poderia sobreviver a fase

  1. MS-ONLINE Mass Spectral Database

    NASA Astrophysics Data System (ADS)

    Tokizane, Soichi; Nagaoka, Nobuaki

    A mass spectral database, MS-ONLINE, is described which is produced by FIZ Chemie, in Federal Republic of Germany and offered online through the INKADATA system. The data source of this database is WILEY/NBS MASS SPECTRAL DATA BASE and it includes 80,680 spectra. Spectral data can be retrieved from a substance search (by assigning molecular weight, molecular formula or name), a specific peak search, or a similarity search of peak patterns called SISCOM search. Further more, the system has functions supporting the component identification of mixtures and the identification from an isotopic abundance. The algorism of the SISCOM search is explained in detail.

  2. Simultaneous quantification of the organophosphorus pesticides dimethoate and omethoate in porcine plasma and urine by LC-ESI-MS/MS and flow-injection-ESI-MS/MS.

    PubMed

    John, Harald; Eddleston, Michael; Clutton, R Eddie; Worek, Franz; Thiermann, Horst

    2010-05-15

    Dimethoate is an organophosphorus toxicant used in agri- and horticulture as a systemic broad-spectrum insecticide. It also exhibits toxic activity towards mammalian organism provoked by catalytic desulfuration in the liver producing its oxon-derivative omethoate thus inhibiting acetylcholinesterase, initiating cholinergic crisis and ultimately leading to death by respiratory paralysis and cardiovascular collapse. Pharmaco- and toxicokinetic studies in animal models help to broaden basic understanding of medical intervention by antidotes and supportive care. Therefore, we developed and validated a LC-ESI-MS/MS method suitable for the simultaneous, selective, precise (RSD(intra-day) 1-8%; RSD(inter-day) 5-14%), accurate (intra-day: 95-107%; inter-day: 90-115%), and robust quantification of both pesticides from porcine urine and plasma after deproteinization by precipitation and extensive dilution (1:11,250 for plasma and 1:40,000 for urine). Accordingly, lower limits of quantification (0.24-0.49 microg/ml plasma and 0.78-1.56 microg/ml urine) and lower limits of detection (0.12-0.24 microg/ml plasma and 0.39-0.78 microg/ml urine) were equivalent to quite low absolute on-column amounts (1.1-2.1 pg for plasma and 2.0-3.9 pg for urine). The calibration range (0.24-250 microg/ml plasma and 0.78-200 microg/ml urine) was subdivided into two linear ranges (r(2)>or=0.998) each covering nearly two orders of magnitude. The lack of any interfering peak in 6 individual blank specimens from plasma and urine demonstrated the high selectivity of the method. Furthermore, extensive sample dilution causing lowest concentration of potentially interfering matrix ingredients prompted us to develop and validate an additional flow-injection method (FI-ESI-MS/MS). Validation characteristics were as good as for the chromatographic method but sample throughput was enhanced by a factor of 6. Effects on ionization provoked by plasma and urine matrix from 6 individuals as well as in the

  3. Identification and quantification of carotenoids, by HPLC-PDA-MS/MS, from Amazonian fruits.

    PubMed

    de Rosso, Veridiana V; Mercadante, Adriana Z

    2007-06-27

    The major and minor carotenoids from six fruits, buriti (Mauritia vinifera), mamey (Mammea americana), marimari (Geoffrola striata), peach palm (Bactrys gasipaes), physalis (Physalis angulata), and tucuma (Astrocaryum aculeatum), all native to the Amazonia region, were determined by high-performance liquid chromatography-photodiode array detector-mass spectrometry detector (HPLC-PDA-MS/MS), fulfilling the recommended criteria for identification. A total of 60 different carotenoids were separated on a C30 column, all-trans-beta-carotene being the major carotenoid found in all fruits. The presence of apo-10'-beta-carotenol, found in mamey, was not previously reported in foods. In addition, this is the first time that the identification of beta-zeacarotene in natural sources is supported by MS data. The total carotenoid content ranged from 38 microg/g in marimari to 514 microg/g in buriti. All fruits analyzed can be considered good sources of provitamin A, especially buriti, with 7280 RE/100 g.

  4. Analysis of peptides using an integrated microchip HPLC-MS/MS system.

    SciTech Connect

    Kirby, Brian J.; Chirica, Gabriela S.; Reichmuth, David S.

    2004-06-01

    Hyphendated LC-MS techniques are quickly becoming the standard tool for protemic analyses. For large homogeneous samples, bulk processing methods and capillary injection and separation techniques are suitable. However, for analysis of small or heterogeneous samples, techniques that can manipulate picoliter samples without dilution are required or samples will be lost or corrupted; further, static nanospray-type flowrates are required to maximize SNR. Microchip-level integration of sample injection with separation and mass spectrometry allow small-volume analytes to be processed on chip and immediately injected without dilution for analysis. An on-chip HPLC was fabricated using in situ polymerization of both fixed and mobile polymer monoliths. Integration of the chip with a nanospray MS emitter enables identification of peptides by the use of tandem MS. The chip is capable of analyzing of very small sample volumes (< 200 pl) in short times (< 3 min).

  5. 61. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER'S BRIDGE Ms. 14, 6 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    61. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER'S BRIDGE Ms. 14, 6 miles E to McLeod, 4.5 miles S on McLeod-Shuqualak road. Overall view of bridge, looking E along N side, from below deck level. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  6. Determination of Aflatoxin B1 in Smokeless Tobacco Products by Use of UHPLC-MS/MS.

    PubMed

    Zitomer, Nicholas; Rybak, Michael E; Li, Zhong; Walters, Matthew J; Holman, Matthew R

    2015-10-21

    This work developed a UHPLC-MS/MS method for the detection and quantitation of aflatoxins in smokeless tobacco products, which was then used to determine aflatoxin B1 concentrations in 32 smokeless tobacco products commercially available in the United States. Smokeless tobacco products were dried, milled, and amended with (13)C17-labeled internal standards, extracted in water/methanol solution in the presence of a surfactant, isolated through use of immunoaffinity column chromatography, and reconstituted in mobile phase prior to UHPLC-MS/MS analysis. The method was capable of baseline separation of aflatoxins B1, B2, G1, and G2 in a 2.5 min run by use of a fused core C18 column and a water/methanol gradient. MS/MS transition (m/z) 313.3 → 241.2 was used for aflatoxin B1 quantitation, with 313.3 → 285.1 used for confirmation. The limit of detection (LOD) for aflatoxin B1 was 0.007 parts per billion (ppb). Method imprecision for aflatoxin B1 (expressed as coefficient of variation) ranged from 5.5 to 9.4%. Spike recoveries were 105-111%. Aflatoxin B1 concentrations in the smokeless tobacco products analyzed ranged from

  7. UFLC-ESI-MS/MS analysis of multiple mycotoxins in medicinal and edible Areca catechu.

    PubMed

    Liu, Hongmei; Luo, Jiaoyang; Kong, Weijun; Liu, Qiutao; Hu, Yichen; Yang, Meihua

    2016-05-01

    A robust, sensitive and reliable ultra fast liquid chromatography combined with electrospray ionization tandem mass spectrometry (UFLC-ESI-MS/MS) was optimized and validated for simultaneous identification and quantification of eleven mycotoxins in medicinal and edible Areca catechu, based on one-step extraction without any further clean-up. Separation and quantification were performed in both positive and negative modes under multiple reaction monitoring (MRM) in a single run with zearalanone (ZAN) as internal standard. The chromatographic conditions and MS/MS parameters were carefully optimized. Matrix-matched calibration was recommended to reduce matrix effects and improve accuracy, showing good linearity within wide concentration ranges. Limits of quantification (LOQ) were lower than 50 μg kg(-1), while limits of detection (LOD) were in the range of 0.1-20 μg kg(-1). The accuracy of the developed method was validated for recoveries, ranging from 85% to 115% with relative standard deviation (RSD) ≤14.87% at low level, from 75% to 119% with RSD ≤ 14.43% at medium level and from 61% to 120% with RSD ≤ 13.18% at high level, respectively. Finally, the developed multi-mycotoxin method was applied for screening of these mycotoxins in 24 commercial samples. Only aflatoxin B2 and zearalenone were found in 2 samples. This is the first report on the application of UFLC-ESI(+/-)-MS/MS for multi-class mycotoxins in A. catechu. The developed method with many advantages of simple pretreatment, rapid determination and high sensitivity is a proposed candidate for large-scale detection and quantification of multiple mycotoxins in other complex matrixes.

  8. Identification of chemical markers in Cordyceps sinensis by HPLC-MS/MS.

    PubMed

    Hu, Hankun; Xiao, Ling; Zheng, Baogen; Wei, Xin; Ellis, Alexis; Liu, Yi-Ming

    2015-10-01

    Authentication and quality assessment of Cordyceps sinensis, a precious and pricey natural product that offers a variety of health benefits, is highly significant. To identify effective chemical markers, authentic C. sinensis was thoroughly screened by using HPLC-MS/MS. In addition to many previously reported ingredients, two glycosides, i.e., cyclo-Ala-Leu-rhamnose and Phe-o-glucose, were detected for the first time in this material. Six ingredients detected, including cordycepin, D-mannitol, Phe, Phe-o-glucose, cyclo-Gly-Pro, and cyclo-Ala-Leu-rhamnose, were selected as a collection of chemical markers. An HPLC-MS/MS method was developed to simultaneously quantify them with sensitivity and specificity. The method had limits of detection ranging from 0.008 μg mL(-1) for cordycepin to 0.75 μg mL(-1) for cyclo-Gly-Pro. Recovery was found between 96 and 103 % in all tests. To evaluate the effectiveness of the marker collection proposed, five authentic C. sinensis samples and five samples of its substitutes were analyzed. Cordycepin, D-mannitol, and Phe were found present in all samples. The contents ranged from 0.0076 to 0.029 % (w/w) for cordycepin, 0.33 to 18.9 % for mannitol, and 0.0013 to 0.642 % for Phe. Interestingly, the two glycosides, Phe-o-glucose and cyclo-Ala-Leu-rhamnose, were detected only in authentic C. sinensis samples. These results indicated that the proposed protocol based on HPLC-MS/MS quantification of the markers might have a great potential in authentication and quality assessment of C. sinensis. Graphical abstract Chemical markers of C. sinensis identified in this work.

  9. Analysis of benzodiazepines and their metabolites using DBS cards and LC-MS/MS.

    PubMed

    Lee, Heesang; Park, Yujin; Jo, Jiyeong; In, Sangwhan; Park, Yonghoon; Kim, Eunmi; Pyo, Jaesung; Choe, Sanggil

    2015-10-01

    Dried Blood Spot (DBS) has been used a blood extraction method for inherited metabolic disorder screening since 1960s. With introduction of LC-MS/MS, not only DBS could be used to analysis drugs in small blood volume, but in various fields, such as toxicology, drug therapeutic monitoring, drug diagnostic screening, and illicit drugs. In toxicology field, many drugs (e.g. benzodiazepines, acetaminophen, small molecule drugs) have been tested with DBS. Compared with earlier blood extraction methods (SPE and LLE), DBS has lots of advantages; lower blood volume (less than 50μL), shorter analysis time caused by a more concise analysis procedure and lower cost. We optimized the DBS procedure and LC-MS/MS conditions for 18 benzodiazepines, seven benzodiazepine metabolites, and one z-drug (zolpidem) analysis in blood. 30μL of whole blood was spotted on FTA DMPK card C and dried for 2h in a desiccator. A 6-mm disk was punched and vortexed for 1min in a centrifuge tube with 300μL methanol/acetonitrile mixture (1:1, v/v). After evaporation, redissolved in 100μL mobile phase of LC-MS/MS and 5μL was injected. In the analysis for 26 target compounds in blood, all of the method validation parameters - LLOD, LLOQ, accuracy (intra- and inter-assay), and precision (intra- and inter-assay) - were satisfied with method validation criteria, within 15%. The results of matrix effect, recovery, and process efficiency were good. We developed a fast and reliable sample preparation method using DBS for 26 benzodiazepines, benzodiazepine metabolites, and z-drug (zolpidem).

  10. [Simultaneous determination of 11 mycotoxins in malt by isotope internal standard-UPLC-MS/MS].

    PubMed

    Wang, Sha; Kong, Wei-jun; Yang, Mei-hua

    2016-01-01

    A suitable ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of 11 mycotoxins with isotope internal standard in malt. The mycotoxins in malt were extracted and purified by one-step ultrasonic extraction procedure using acetonitrile/water/acetic acid (80 : 19 : 1), and then detected and confirmed by UPLC-MS/MS, and quantified by isotope labeled AFB1 ([13C17]-AFB1) and ZEN ([13C18]-ZEN) internal standards. Rapid separation of the 11 mycotoxins was successfully achieved on a Phenomenex Kinetex C18 column (100 mm x 2.1 mm, 2.6 μm) with gradient elution using the mobile phase of methanol containing 0.1% formic acid and 2 mmol x L(-1) ammonium acetate in water. Simultaneous acquisition was performed in multiple reaction monitoring (MRM) mode with electrospray ionization (ESI) source operated in both positive and negative ionization modes. The established method provided a good linearity for the 11 mycotoxins within their respective linear ranges with correlation coefficients all higher than 0.999 1. The average recoveries ranged from 75.0% to 117.0% with relative standard deviations (RSDs) below 5.1%. The limits of detection (LODs) and quantitation (LOQs) ranged from 0.05 to 30 μg x kg(-1) and 0.15 to 87.5 μg x kg(-1), respectively, which were below the maximum residue levels (MRLs) set by the European Union. Twenty malt samples were analyzed and nine samples were detected with mycotoxins, which were confirmed according to the same fragment ions found in positive samples and the standards at the same retention time. This study has demonstrated that the one-step extraction procedure of mycotoxins from complex matrices coupled to UPLC-MS/MS method is simple, quick, accurate and sensitive for quantitative and qualitative analysis of multiple mycotoxins in malt.

  11. Techniques for quantitative LC-MS/MS analysis of protein therapeutics: advances in enzyme digestion and immunocapture.

    PubMed

    Fung, Eliza N; Bryan, Peter; Kozhich, Alexander

    2016-04-01

    LC-MS/MS has been investigated to quantify protein therapeutics in biological matrices. The protein therapeutics is digested by an enzyme to generate surrogate peptide(s) before LC-MS/MS analysis. One challenge is isolating protein therapeutics in the presence of large number of endogenous proteins in biological matrices. Immunocapture, in which a capture agent is used to preferentially bind the protein therapeutics over other proteins, is gaining traction. The protein therapeutics is eluted for digestion and LC-MS/MS analysis. One area of tremendous potential for immunocapture-LC-MS/MS is to obtain quantitative data where ligand-binding assay alone is not sufficient, for example, quantitation of antidrug antibody complexes. Herein, we present an overview of recent advance in enzyme digestion and immunocapture applicable to protein quantitation.

  12. [Determination method of ultra-high-intensity sweetener, advantame, in processed foods by HPLC and LC-MS/MS].

    PubMed

    Kobayashi, Miki; Terada, Hisaya; Nakajima, Masahiro

    2015-01-01

    A simple method using HPLC and LC-MS/MS was developed for the determination of ultra-high-intensity sweetener, advantame, in processed foods. Advantame was extracted by dialysis, and cleaned up on a Sep-Pak Plus C18 cartridge, then determined by HPLC and LC-MS/MS. The recoveries from 5 kinds of processed foods fortified at the levels of 0.001 g/kg and 0.01 g/kg were 64.1-89.9% (RSD 0.9-6.9%) by HPLC and 68.8-99.9% (RSD 0.8-4.9%) by LC-MS/MS. The quantitation limit was 0.0004 g/kg by HPLC and 0.00004 g/kg by LC-MS/MS.

  13. Development of multi-residue sulfonamide analysis using LC-MS/MS for detection in wastewater and river samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A qTOF-LC-MS/MS method was developed for multi-residue analysis of sulfonamides, including sulfathiazole, sulfadiazine, sulfapyridine, sulfamerazine, sulfamethizole, sulfamethazine, sulfachloropydirine, sulfamethoxazole (SMX), sulfadimethoxine, sulfabenzamide, sulfaquinoxaline, and sulfasalazine. Tw...

  14. STS-47 MS Davis and MS Jemison conduct LBNP experiment in the SLJ module

    NASA Technical Reports Server (NTRS)

    1992-01-01

    At the aft end of the Spacelab Japan (SLJ) science module, STS-47 Mission Specialist (MS) N. Jan Davis (foreground) readies Rack 9 Automatic Blood Pressure System (ABPS) controls as MS Mae C. Jemison, inside the cylindrical fabric lower body negative pressure (LBNP) device, waits for the LBNP experiment to begin. LBNP device is sealed around Jemison's waist. It is attached to the SLJ floor and has a controller that operates a pump to change the pressure inside. Davis will monitor Jemison's pulse rate, blood pressure, and cardiac dimensions and functions.

  15. STS-31 MS Sullivan, MS McCandless, DSO 462 medical device on OV-103 middeck

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 Mission Specialist (MS) Kathryn D. Sullivan applies a gel to a transducer while MS Bruce McCandless II uses a central venous pressure mouthpiece on the middeck of Discovery, Orbiter Vehicle (OV) 103. The crewmembers are conducting Detailed Supplementary Objective (DSO) 462, Non-Invasive Estimation of Central Venous Pressure. After preparing the transducer, Sullivan will apply it to McCandless' juggler. DSO 462 will measure the physiological adaptation to the headward shift that occurs in microgravity. This non-invasive technique of determining central venous pressure uses the mouthpiece with varying resistance and a probe that utilizes Doppler flowmetry.

  16. STS-54 MS2 Harbaugh and MS3 Helms during slidewire egress training at KSC

    NASA Technical Reports Server (NTRS)

    1993-01-01

    STS-54 Endeavour, Orbiter Vehicle (OV) 105, Mission Specialist (MS2) Gregory J. Harbaugh (left) and MS3 Susan J. Helms, wearing launch and entry suits (LESs) and launch and entry helmets (LEHs), listen to instructions during emergency egress system (slidewire) training at a Kennedy Space Center (KSC) Launch Complex (LC) tower. The two crewmembers, positioned in a slidewire litter (basket), watch as Lockheed (Houston) technician Max Kandler, wearing stocking hat, performs final checks before sending them down the slidewire. The emergency egress training was part of the preflight terminal countdown demonstration tests (TCDTs).

  17. Targeted pesticide residue analysis using triple Quad LC-MS/MS.

    PubMed

    Alder, Lutz

    2011-01-01

    The determination of pesticide residues by HPLC-MS/MS requires decisions on a multitude of analytical parameters. This includes the selection of eluents, columns and ion sources, but also the optimization of the tandem mass spectrometer for the selected target analytes. Another aspect is the use of the restricted acquisition time between two chromatographic data points. An appropriate selection of all these parameters as well as the measures to avoid interference by cross talks and wrong quantitative results by matrix effects is discussed in this chapter.

  18. HPLC-ESI-MS/MS determination of zuclopenthixol in a fatal intoxication during psychiatric therapy.

    PubMed

    Kollroser, M; Henning, G; Gatternig, R; Schober, C

    2001-12-01

    The first non-suicidal fatality due to intramuscular administration of Cisordinol (zuclopenthixol, ZPT) is described. A new, rapid, and sensitive method for the determination of ZPT in postmortem specimens has been developed. High performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was employed for drug confirmation and quantitation. Sample clean up was performed using a simple liquid-liquid extraction procedure. The postmortem concentration of ZPT in heart blood was 0.68 microg/ml. Furthermore, zotepine, carbamazepine, and chlorprotixene were detected in body fluids. The proposed method enables the unambiguous identification and quantitation of ZPT and other neuroleptic drugs in clinical and forensic specimens.

  19. STS-54 MS2 Harbaugh and MS3 Helms during training in JSC's ETA / airlock

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-54 Endeavour, Orbiter Vehicle (OV) 105, Mission Specialist (MS2) Gregory J. Harbaugh, wearing an extravehicular mobility unit (EMU) and communications carrier assembly (CCA), is assisted by MS3 Susan J. Helms during Environmental Test Article (ETA) / Airlock training (STB-SS-956) in JSC's Crew Systems Laboratory Bldg 7. Helms readies the EMU glove as Harbaugh looks on. Though not assigned to the scheduled STS-54 extravehicular activity (EVA), Helms will assist Harbaugh in EVA preparations as she does here and will serve as a backup EVA crewmember. Two crewmembers will perform a four-hour-plus spacewalk during STS-54.

  20. Analysis of pesticide residues in strawberries and soils by GC-MS/MS, LC-MS/MS and two-dimensional GC-time-of-flight MS comparing organic and integrated pest management farming.

    PubMed

    Fernandes, Virgínia C; Lehotay, Steven J; Geis-Asteggiante, Lucía; Kwon, Hyeyoung; Mol, Hans G J; van der Kamp, Henk; Mateus, Nuno; Domingues, Valentina F; Delerue-Matos, Cristina

    2014-01-01

    This study analysed 22 strawberry and soil samples after their collection over the course of 2 years to compare the residue profiles from organic farming with integrated pest management practices in Portugal. For sample preparation, we used the citrate-buffered version of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. We applied three different methods for analysis: (1) 27 pesticides were targeted using LC-MS/MS; (2) 143 were targeted using low pressure GC-tandem mass spectrometry (LP-GC-MS/MS); and (3) more than 600 pesticides were screened in a targeted and untargeted approach using comprehensive, two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Comparison was made of the analyses using the different methods for the shared samples. The results were similar, thereby providing satisfactory confirmation of both similarly positive and negative findings. No pesticides were found in the organic-farmed samples. In samples from integrated pest management practices, nine pesticides were determined and confirmed to be present, ranging from 2 µg kg(-1) for fluazifop-p-butyl to 50 µg kg(-1) for fenpropathrin. Concentrations of residues in strawberries were less than European maximum residue limits.

  1. ms_lims, a simple yet powerful open source laboratory information management system for MS-driven proteomics.

    PubMed

    Helsens, Kenny; Colaert, Niklaas; Barsnes, Harald; Muth, Thilo; Flikka, Kristian; Staes, An; Timmerman, Evy; Wortelkamp, Steffi; Sickmann, Albert; Vandekerckhove, Joël; Gevaert, Kris; Martens, Lennart

    2010-03-01

    MS-based proteomics produces large amounts of mass spectra that require processing, identification and possibly quantification before interpretation can be undertaken. High-throughput studies require automation of these various steps, and management of the data in association with the results obtained. We here present ms_lims (http://genesis.UGent.be/ms_lims), a freely available, open-source system based on a central database to automate data management and processing in MS-driven proteomics analyses.

  2. Identification of Bacteria Using Phylogenetic Relationships, Revealed by MS/MS Sequencing of Tryptic Peptides Derived from Cellular Proteins

    DTIC Science & Technology

    2004-11-17

    Universal Phylogenetic Tree of Bacteria Based on SSU rRNA Sequences Aquificae Termotogae Planctomycetes Actinobacteria Firmicutes Cyanobacteria...Identification of Bacteria Using Phylogenetic Relationships Revealed by MS/MS Sequencing of Tryptic Peptides Derived from Cellular Proteins Jacek P...Bacteria Using Phylogenetic Relationships Revealed by MS/MS Sequencing of Tryptic Peptides Derived from Cellular Proteins 5a. CONTRACT NUMBER 5b. GRANT

  3. Robert Carswell: the first illustrator of MS.

    PubMed

    Murray, T J

    2009-09-01

    The first illustration of multiple sclerosis (MS) was by a young Scottish physician and artist, Dr Robert Carswell. Recognized as a talented illustrator by his teachers, he was encouraged to create an anatomy and pathology atlas. He spent years in the hospitals and mortuaries of Paris and Lyon painting watercolours and pen and ink drawings of patients and post mortem preparations. Of the 1034 paintings, 99 are of the brain and spinal cord and Plate 4, figure 4.4 in the atlas (Figure 2), is of MS. Carswell indicated he saw two examples of this pathology, but had not examined either patient, but illustrated one of them. We know little about the clinical history other than that the patient was paralyzed. About 200 of the atlases were printed, and it is still regarded as one of the greatest and most beautiful of all medical books. Carswell was appointed as the first Professor of Anatomy at the North London Hospital, later renamed the University College Hospital UK, where the original copy of his great atlas is archived. Due to ill health he resigned after a few years to reside in the healthier air outside Brussels, Belgium. He was appointed physician to King Leopold, but was also noted for his care of the poor. Queen Victoria knighted him for his care of King Louis Philippe of France when he was in exile. Although English journals did not note his passing at the age of 64 years, his great atlas remains as his memorial.

  4. EMS in Mauritius.

    PubMed

    Ramalanjaona, Georges; Brogan, Gerald X

    2009-02-01

    Mauritius lies in the southwest Indian Ocean about 1250 miles from the African coast and 500 miles from Madagascar. Mauritius (estimated population 1,230,602) became independent from the United Kingdom in 1968 and has one of the highest GDP per capita in Africa. Within Mauritius there is a well established EMS system with a single 999 national dispatch system. Ambulances are either publicly or privately owned. Public ambulances are run by the Government (SAMU). Megacare is a private subscriber only ambulance service. The Government has recently invested in new technology such as telemedicine to further enhance the role of EMS on the island. This article describes the current state of EMS in Mauritius and depicts its development in the context of Government effort to decentralise and modernise the healthcare system.

  5. Measurement of unlabeled and stable isotope-labeled homoarginine, arginine and their metabolites in biological samples by GC-MS and GC-MS/MS.

    PubMed

    Kayacelebi, Arslan Arinc; Knöfel, Ann-Kathrin; Beckmann, Bibiana; Hanff, Erik; Warnecke, Gregor; Tsikas, Dimitrios

    2015-09-01

    Circulating and excretory L-homoarginine (hArg) and asymmetric dimethylarginine (ADMA) are cardiovascular risk factors. L-Arginine (Arg) is the common precursor of hArg and ADMA. This protocol describes gas chromatography-mass spectrometry (GC-MS) and gas chromatography-mass spectrometry-mass spectrometry (GC-MS/MS) methods for the quantitative determination of hArg, Arg and ADMA in biological samples, including human plasma, urine and sputum. Aliquots (10 µL) of native urine, plasma or serum ultrafiltrate (cutoff, 10 kDa), and acetone-deproteinized sputum samples are evaporated to dryness. Then, amino acids are derivatized to their methyl ester N-pentafluoropropionyl derivatives. In parallel, trideuteromethyl ester N-pentafluoropropionyl derivatives of hArg, Arg and ADMA are de novo synthesized from the unlabelled amino acids and used as internal standards. Alternatively, commercially available stable isotope-labeled analogs of hArg, Arg and ADMA are used as internal standards, and they are added to the native biological samples. Quantification is performed by selected ion monitoring in GC-MS and selected reaction monitoring in GC-MS/MS. By these protocols, unlabelled and stable isotope-labeled hArg, Arg and their metabolites including ADMA and ornithine can be measured equally accurately and precisely by GC-MS and GC-MS/MS in several different biological fluids in experimental and clinical settings.

  6. The comparison of glycosphingolipids isolated from an epithelial ovarian cancer cell line and a nontumorigenic epithelial ovarian cell line using MALDI-MS and MALDI-MS/MS.

    PubMed

    Rajanayake, Krishani K; Taylor, William R; Isailovic, Dragan

    2016-08-05

    Glycosphingolipids (GSLs) are important biomolecules, which are linked to many diseases such as GSL storage disorders and cancer. Consequently, the expression of GSLs may be altered in ovarian cancer cell lines in comparison to apparently healthy cell lines. Here, differential expressions of GSLs in an epithelial ovarian cancer cell line SKOV3 and a nontumorigenic epithelial ovarian cell line T29 were studied using matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and MALDI-MS/MS. The isolation of GSLs from SKOV3 and T29 cell lines was carried out using Folch partition. GSLs were successfully detected by MALDI-MS, and structurally assigned by a comparison of their MALDI-MS/MS fragmentation patterns with MS/MS data found in SimLipid database. Additionally, LIPID MAPS was used to assign GSL ion masses in MALDI-MS spectra. Seventeen neutral GSLs were identified in Folch partition lower (chloroform/methanol) phases originating from both cell lines, while five globo series neutral GSLs were identified only in the Folch partition lower phase of SKOV3 cell line. Several different sialylated GSLs were detected in Folch partition upper (water/methanol) phases of SKOV3 and T29 cell lines. Overall, this study demonstrates the alteration and increased glycosylation of GSLs in an epithelial ovarian cancer cell line in comparison to a nontumorigenic epithelial ovarian cell line.

  7. ANALYSIS OF DISINFECTION BY-PRODUCTS IN DRINKING WATER BY LC-MS AND RELATED MS TECHNIQUES

    EPA Science Inventory

    This review covers recent applications of LC/MS and other related techniques such as flow injection-atmospheric pressure chemical ionization and electrospray ionization-MS, high-field asymmetric waveform ion mobility spectrometry-electrospray ionization-MS, membrane introduction ...

  8. Identification of monomenthyl succinate in natural mint extracts by LC-ESI-MS-MS and GC-MS.

    PubMed

    Marin, Christophe; Schippa, Christine

    2006-06-28

    Fresh and dried mint leaves Mentha piperita (peppermint) and Mentha spicata (spearmint) were extracted in two different ways and the extracts investigated by high performance liquid chromatography-tandem mass spectrometry. All the ethanolic extracts prepared with Soxhlet apparatus were used in the identification of monomenthyl succinate as previously reported. The highest level was found in fresh spearmint leaves. The analysis of the extractions, prepared under mild conditions using a fluorinated solvent (HFC 134-a), confirmed the natural occurrence of monomenthyl succinate in the leaves, ruling out the hypothesis that this constituent could be an artifact of the Soxhlet extraction process. A method for identifying this compound in such a fluorinated solvent extract of mint leaf using preliminary esterification with diazomethane and then GC-MS is described.

  9. Determination of Plutonium Isotope Ratios at Very Low Levels by ICP-MS using On-Line Electrochemically Modulated Separations

    SciTech Connect

    Liezers, Martin; Lehn, Scott A; Olsen, Khris B; Farmer, Orville T; Duckworth, Douglas C

    2009-10-01

    Electrochemically modulated separations (EMS) are shown to be a rapid and selective means of extracting and concentrating Pu from complex solutions prior to isotopic analysis by inductively coupled plasma mass spectrometry (ICP-MS). This separation is performed in a flow injection mode, on-line with the ICP-MS. A three-electrode, flow-by electrochemical cell is used to accumulate Pu at an anodized glassy carbon electrode by redox conversion of Pu(III) to Pu (IV&VI). The entire process takes place in 2% v/v (0.46M) HNO3. No redox chemicals or acid concentration changes are required. Plutonium accumulation and release is redox dependent and controlled by the applied cell potential. Thus large transient volumetric concentration enhancements can be achieved. Based on more negative U(IV) potentials relative to Pu(IV), separation of Pu from uranium is efficient, thereby eliminating uranium hydride interferences. EMS-ICP-MS isotope ratio measurement performance will be presented for femtogram to attogram level plutonium concentrations.

  10. Validation of Electrochemically Modulated Separations Performed On-Line with MC-ICP-MS for Uranium and Plutonium Isotopic Analyses

    SciTech Connect

    Liezers, Martin; Olsen, Khris B.; Mitroshkov, Alexandre V.; Duckworth, Douglas C.

    2010-08-11

    The most time consuming process in uranium or plutonium isotopic analyses is performing the requisite chromatographic separation of the actinides. Filament preparation for thermal ionization (TIMS) adds further delays, but is generally accepted due to the unmatched performance in trace isotopic analyses. Advances in Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) are beginning to rival the performance of TIMS. Methods, such as Electrochemically Modulated Separations (EMS) can efficiently pre-concentrate U or Pu quite selectively from small solution volumes in a matrix of 0.5 M nitric acid. When performed in-line with ICP-MS, the rapid analyte release from the electrode is fast, and large transient analyte signal enhancements of >100 fold can be achieved as compared to more conventional continuous nebulization of the original starting solution. This makes the approach ideal for very low level isotope ratio measurements. In this paper, some aspects of EMS performance are described. These include low level Pu isotope ratio behavior versus concentration by MC-ICP-MS and uranium rejection characteristics that are also important for reliable low level Pu isotope ratio determinations.

  11. 3D imaging of biological specimen using MS.

    PubMed

    Fletcher, John S

    2015-01-01

    Imaging MS can provide unique information about the distribution of native and non-native compounds in biological specimen. MALDI MS and secondary ion MS are the two most commonly applied imaging MS techniques and can provide complementary information about a sample. MALDI offers access to high mass species such as proteins while secondary ion MS can operate at higher spatial resolution and provide information about lower mass species including elemental signals. Imaging MS is not limited to two dimensions and different approaches have been developed that allow 3D molecular images to be generated of chemicals in whole organs down to single cells. Resolution in the z-dimension is often higher than in x and y, so such analysis offers the potential for probing the distribution of drug molecules and studying drug action by MS with a much higher precision - possibly even organelle level.

  12. Analysis of six relevant toxaphene congeners in biological samples using ion trap MS/MS.

    PubMed

    Gouteux, Bruno; Lebeuf, Michel; Trottier, Steve; Gagné, Jean-Pierre

    2002-10-01

    The quantification of six polychlorinated bornanes (CHBs) was studied using ion trap MS/MS. The significance of the selection of parent ions (Ip) and daughter ions (Id) on the detection of these toxaphene congeners was assessed in standard solution and biological samples. Our results indicate that different Ip and Id, selected at either low or high mass-to-charge (m/z) ratios, influence drastically the response factor of the CHBs and the chemical noise observed. For the octachlorinated toxaphene congeners (Parlar-26 (P-26), Parlar-40/41 (P-40/41), Parlar-44 (P-44)), the detection performance of the ion trap MS/MS is similar whether Ip and Id were chosen at low or high m/z ratios. However, the selection of Ip and Id at high m/z ratios clearly enhances the detection of the nonachlorinated toxaphene congeners (Parlar-50 (P-50), Parlar-62 (P-62)). The improved method, which selects Ip and Id at low m/z ratios for P-26, P-40/41 and P-44 and at high m/z ratios for P-50 and P-62, permitted to obtain low detection limits as well as repeatable and accurate results.

  13. Determination and confirmation of nitrofuran residues in honey using LC-MS/MS.

    PubMed

    Lopez, Mayda I; Feldlaufer, Mark F; Williams, Anthony D; Chu, Pak-Sin

    2007-02-21

    A method was developed for the determination and confirmation of furazolidone, nitrofurazone, furaltadone, and nitrofurantoin as their side-chain residues in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). An initial solid-phase extraction cleanup of the honey samples was followed by overnight hydrolysis and derivatization of the nitrofuran side-chain residues with 2-nitrobenzaldehyde. After pH adjustment and liquid-liquid extraction, the extracts were assayed by LC-MS/MS using electrospray ionization in the positive ion mode. The method was validated at concentrations ranging from 0.5 to 2.0 ppb with accuracies of 92-103% and coefficients of variation of < or =10%. The lowest calibration standard used (0.25 ppb) was defined as the limit of quantitation for all four nitrofuran side-chain residues. The extracts and standards were also used for confirmatory purposes. Honey from dosed beehives was assayed to study the stability of the nitrofuran residues and to demonstrate the effectiveness of the method.

  14. Validation of an HPLC-MS/MS and Wipe Procedure for Mitomycin C Contamination

    PubMed Central

    B’Hymer, C.; Connor, T.H.; Stinson, D.; Pretty, J.R.

    2015-01-01

    A high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the determination of mitomycin C, an anticancer drug, from contamination on various surfaces. Mitomycin C is often used in various forms of intraperitoneal chemotherapy, and operating room healthcare worker exposure to this drug is possible. The surface testing method consisted of a wiping procedure utilizing a solution of 20/45/35 (v/v/v) of acetonitrile-isopropanol-water made 0.01 M in ammonium citrate (apparent pH 7.0). The wipe solutions were analyzed by means of HPLC-MS/MS using a reversed-phase gradient system and electrospray ionization in positive ion-mode with a triple-quadrupole mass spectrometric detector. Accuracy and precision of this method were demonstrated by a series of recovery studies of both spiked solutions and extracted wipes from various surfaces (stainless steel, vinyl and Formica®) spiked with known levels of mitomycin C. Recoveries of spiked solutions containing the analyte demonstrate mean recoveries (accuracy) ranged from 93 to 105%. Precision as measured by the relative standard deviation (%RSD) of multiple samples (n=10) at each concentration level demonstrated values of 7.5% or less. The recoveries from spiked surfaces varied from 30 to 99%. The limit of detection (LOD) for this methodology is approximately 2 ng/100 cm2 equivalent surface area, and the limit of quantitation (LOQ) is approximately 6 ng/100 cm2. PMID:25129062

  15. Photocatalytic degradation of hexazinone and its determination in water via UPLC-MS/MS.

    PubMed

    Mei, Mei; Du, Zhenxia; Xu, Ruifen; Chen, Yun; Zhang, Haojie; Qu, Shuping

    2012-06-30

    Degradation of hexazinone has been investigated by means of photocatalysis of mixed-phase crystal nano-TiO(2). Influences of adsorption, amount of nano-TiO(2), pH and irradiation time on the photocatalytic process are studied. Results show that hexazinone is totally degraded within 40min of irradiation under pH neutral conditions. This compares favorably with Degussa P25 TiO(2) when conducted under the same experimental conditions. Preliminary photocatalytic kinetic information for hexazinone degradation is proposed. First order kinetics is obtained for the adsorption and photocatalytic degradation reactions, which fit the Langmuir-Hinshelwood model. A rapid, sensitive and accurate UPLC-MS/MS technique is developed and utilized to determine the level of hexazinone in water in support of the degradation kinetics study. The results indicate a limit of detection (LOD) at 0.05μg/l and the recoveries between 90.2 and 98.5% with relative standard deviations (RSD) lower than 12%. A LC-MS/MS technique is used to trace the degradation process. Complete degradation is achieved into final products including nontoxic water, carbon dioxide and urea. A probable pathway for the total photocatalytic degradation of hexazinone is proposed.

  16. Potential Health Benefits and Metabolomics of Camel Milk by GC-MS and ICP-MS.

    PubMed

    Ahamad, Syed Rizwan; Raish, Mohammad; Ahmad, Ajaz; Shakeel, Faiyaz

    2017-02-01

    None of the research reports reveals the metabolomics and elemental studies on camel milk. Recent studies showed that camel milk possesses anticancer and anti-inflammatory activity. Metabolomics and elemental studies were carried out in camel milk which showed us the pathways and composition that are responsible for the key biological role of camel milk. Camel milk was dissolved in methanol and chloroform fraction and then vortexed and centrifuged. Both the fractions were derivatized by N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) and TMCS after nitrogen purging and analyzed by GC-MS. Camel milk was also analyzed by ICP-MS after microwave digestion. We found that higher alkanes and fatty acids are present in the chloroform fraction and amino acids, sugars and fatty acid derivatives are present in aqueous fractions. All the heavy metals like As, Pb, Cd, Co, Cu, and Ni were in the safe limits in terms of maximum daily intake of these elements. Na, K, Mg, and Ca were also present in the safe limits in terms of maximum daily intake of these elements. These results suggested that the camel milk drinking is safe and there is no health hazard. The present data of GC-MS and ICP-MS correlate the activities related to camel milk.

  17. Novel LC/MS/MS and High-Throughput Mass Spectrometric Assays for Monoacylglycerol Acyltransferase Inhibitors.

    PubMed

    Qi, Jenson; Masucci, John A; Lang, Wensheng; Connelly, Margery A; Caldwell, Gary W; Petrounia, Ioanna; Kirkpatrick, Jennifer; Barnakov, Alexander N; Struble, Geoffrey; Miller, Robyn; Dzordzorine, Keli; Kuo, Gee-Hong; Gaul, Michael; Pocai, Alessandro; Lee, Seunghun

    2017-04-01

    Monoacylglycerol acyltransferase enzymes (MGAT1, MGAT2, and MGAT3) convert monoacylglycerol to diacylglycerol (DAG). MGAT1 and MGAT2 are both implicated in obesity-related metabolic diseases. Conventional MGAT enzyme assays use radioactive substrates, wherein the product of the MGAT-catalyzed reaction is usually resolved by time-consuming thin layer chromatography (TLC) analysis. Furthermore, microsomal membrane preparations typically contain endogenous diacylglycerol acyltransferase (DGAT) from the host cells, and these DGAT activities can further acylate DAG to form triglyceride (TG). Our mass spectrometry (liquid chromatography-tandem mass spectrometry, or LC/MS/MS) MGAT2 assay measures human recombinant MGAT2-catalyzed formation of didecanoyl-glycerol from 1-decanoyl-rac-glycerol and decanoyl-CoA, to produce predominantly 1,3-didecanoyl-glycerol. Unlike 1,2-DAG, 1,3-didecanoyl-glycerol is proved to be not susceptible to further acylation to TG. 1,3-Didecanoyl-glycerol product can be readily solubilized and directly subjected to high-throughput mass spectrometry (HTMS) without further extraction in a 384-well format. We also have established the LC/MS/MS MGAT activity assay in the intestinal microsomes from various species. Our assay is proved to be highly sensitive, and thus it allows measurement of endogenous MGAT activity in cell lysates and tissue preparations. The implementation of the HTMS MGAT activity assay has facilitated the robust screening and evaluation of MGAT inhibitors for the treatment of metabolic diseases.

  18. LC-MS/MS Validation Analysis of Trastuzumab Using dSIL Approach for Evaluating Pharmacokinetics.

    PubMed

    Budhraja, Rohit H; Shah, Milin A; Suthar, Mahendra; Yadav, Arun; Shah, Sahil P; Kale, Prashant; Asvadi, Parisa; Valan Arasu, Mariadhas; Al-Dhabi, Naif Abdullah; Park, Chun Geon; Kim, Young-Ock; Kim, Hak Jae; Agrawal, Y K; Krovidi, Ravi K

    2016-11-02

    Quantitative targeted proteomics based approaches deploy state-of-the-art Liquid chromatography tandem mass spectrometry LC-MS technologies and are evolving as a complementary technique to standard ligand-binding based assays. Advancements in MS technology, which have augmented the specificity, selectivity and sensitivity limits of detection and freedom from antibody generation, have made it amicable towards various clinical applications. In our current work, a surrogate peptide based quantitative proteomics assessment is performed by selecting specific signature peptides from the complementary determining region CDR region of trastuzumab (Herclon(®), Roche products in India). We developed a double Stable Isotope Label (dSIL) approach by using two different surrogate peptides to evaluate the proteolytic digestion efficiency and accurate quantification of the target analyte peptide of Herclon(®) in human serum. Method validation experiments were meticulously performed as per bioanalytical method validation guidelines. The dSIL approach, using an LC-MS/MS based quantification assay demonstrated good linearity over a range of 5-500 µg/mL of Herclon(®), and validation experimental data is in compliance with bioanalytical regulatory guidelines.

  19. Rapid Analysis of Listeria monocytogenes Cell Wall Teichoic Acid Carbohydrates by ESI-MS/MS

    PubMed Central

    Eugster, Marcel R.; Loessner, Martin J.

    2011-01-01

    We report the application of electrospray ionization (ESI) mass spectrometry for compositional characterization of wall teichoic acids (WTA), a major component of Gram-positive bacterial cell walls. Tandem mass spectrometry (ESI-MS/MS) of purified and chemically hydrolyzed monomeric WTA components provided sufficient information to identify WTA monomers and their specific carbohydrate constituents. A lithium matrix was used for ionization of uncharged WTA monomers, and successfully applied to analyze the WTA molecules of four Listeria strains differing in carbohydrate substitution on a conserved polyribitol-phosphate backbone structure. Carbohydrate residues such as N-acetylglucosamine or rhamnose linked to the WTA could directly be identified by ESI-MS/MS, circumventing the need for quantitative analysis by gas chromatography. The presence of a terminal N-acetylglucosamine residue tethered to the ribitol was confirmed using fluorescently labeled wheat-germ agglutinin. In conclusion, the mass spectrometry method described here will greatly facilitate compositional analysis and characterization of teichoic acids and similar macromolecules from diverse bacterial species, and represents a significant advance in the identification of serovar-specific carbohydrates and sugar molecules on bacteria. PMID:21738682

  20. Determination of residual fipronil in chicken egg and muscle by LC-MS/MS.

    PubMed

    Zhang, Meiyu; Bian, Kui; Zhou, Tong; Song, Xuqin; Liu, Qingying; Meng, Chenying; He, Limin

    2016-03-01

    A simple, sensitive and reliable method was developed and applied to the residue analysis of fipronil in chicken egg and muscle by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chicken egg and muscle samples were extracted with acetronitrile, then salting out by dehydration with anhydrous magnesium sulfate and sodium chloride. The extracts were purified by the C18 solid phase extraction cartridge prior to analysis by LC-MS/MS. The matrix-matched calibration curve showed a good linear within the concentration range from 0.01 to 2.00μgkg(-1) (r(2)≥0.999). The average recoveries of fipronil at three spiked levels of 0.01, 0.1 and 1.0μgkg(-1) ranged from 79.7% to 98.0%, and the relative standard deviations were less than 8.8%. The decision limit (CCα) and detection capability (CCβ) of fipronil in chicken egg and muscle matrices were all 0.002μgkg(-1) and 0.01μgkg(-1), respectively. The method has also been successfully applied to monitoring fipronil in the real samples.

  1. Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA) in Milk.

    PubMed

    Andjelkovic, Mirjana; Tsilia, Varvara; Rajkovic, Andreja; De Cremer, Koen; Van Loco, Joris

    2016-04-20

    Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs) in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS) based on multiple reaction monitoring (MRM) was used to detect and quantify two types of SE (A and B) spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively.

  2. Simultaneous determination of β-agonists and psychiatric drugs in feeds by LC-MS-MS.

    PubMed

    Suo, D C; Zhao, G L; Wang, P L; Su, X O

    2014-08-01

    A method was developed for the simultaneous determination of nine β-agonists (cimaterol, ractopamine, terbutaline, zilpaterol, salbutamol, clenbuterol, mabuterol, bambuterol and brombuterol) and six psychiatric drugs (diazepam, nitrazepam, oxazepam, chlorpromazine, promethazine and perphenazine) in animal feed by using solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Conditions were optimized for the extraction of the target analytes from animal feed and for clean-up with MCX SPE cartridges. The eluent was evaporated to dryness under nitrogen, and the residue was dissolved in a solution of acetonitrile and 1% formic acid (2:8, v/v) and analyzed by LC-MS-MS using an isotopic internal standard for quantification. Under the optimum conditions, the recovery values of the target analytes were between 70.1 and 110%, with coefficients of variation between 1.9 and 18.4%. The method was very reliable for the simultaneous determination of nine β-agonists and six psychiatric drugs in animal feed.

  3. Simultaneous Determination of 11 Illicit Phenethylamines in Hair by LC-MS-MS: In Vivo Application.

    PubMed

    Nieddu, Maria; Burrai, Lucia; Demontis, Maria Piera; Varoni, Maria Vittoria; Baralla, Elena; Trignano, Claudia; Boatto, Gianpiero

    2015-09-01

    Existing phenethylamines are a class of synthetic compounds that differ from each other only in small changes to a largely conserved chemical structure. The recreational and illicit use of phenethylamines is a widespread problem. A simple procedure for the simultaneous quantitative determination in hair of 11 phenethylamines that are officially recognized as illicit by Italian legislation (p-methoxyamphetamine; p-methoxymethamphetamine; 3,4,5-trimethoxyamphetamine; 2,5-dimethoxyamphetamine; 2,5-dimethoxy-4-methylamphetamine; 2,5-dimethoxy-4-ethylamphetamine; 2,5-dimethoxy-4-bromoamphetamine; 2,5-dimethoxy-4-bromophenethylamine; 2,5-dimethoxy-4-iodophenethylamine; 2,5-dimethoxy-4-ethylthiophenethylamine and 2,5-dimethoxy-4-n-propylthiophenethylamine) has been developed and validated. Extraction from the matrix was performed after incubation in methanolic HCl and filtered reconstituted extracts were injected into a liquid chromatography/tandem mass spectrometry system (LC-MS-MS) without any further purification steps. This validated LC-MS-MS method has been used to determine the in vivo accumulation/retention of the above target analytes in hair after repeat oral administration to rats. This experiment further permitted investigation of the effect of pigmentation on the uptake of these phenethylamines by hair and the effect of hair pigmentation. The developed method could potentially be used for forensic and toxicological purposes, in the detection and quantitation of these illicit substances in human hair in workplace drug testing; drug-facilitated crime investigation; driver re-licensing; determining drug abuse history and postmortem toxicology.

  4. [Simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS following derivatization].

    PubMed

    Liu, Xiao-Fen; Ding, Cun-Gang; Ge, Qing-Hua; Zhou, Zhen; Zhi, Xiao-Jin

    2010-01-01

    To establish a sensitive and specific method for simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS, plasma samples were extracted and derivatized before injection. An ESI ion source was used and operated in the positive ion mode with multiple reaction monitoring (MRM). Norgestrel was chosen as internal standard and performed on a C18 (100 mm x 2.1 mm, 5 microm) column. The concentrations of gestodene, etonogestrel and ethinylestradiol were measured, using step-gradient mobile phase and step-gradient flow rate. The method was validated over the concentration range of 0.1-20 ng x mL(-1) for gestodene and etonogestrel and 0.01-2 ng x mL(-1) for ethinylestradiol, and showed excellent linearity. The intra- and inter-assay accuracy and precision were below 10.0% and recovery was 93.6%-110.9% over the three concentration levels evaluated. The method was applied in pharmacokinetic study of the compound gestodene patch and the compound etonogestrel patch in rabbits. The LC-MS/MS method was selective, accurate and sensitive, especially the LOQ were 100 pg x mL(-1) for gestodene and etonogestrel and 10 pg x mL(-1) for ethinylestradiol. The method was successfully applied in pharmacokinetic study for contraceptives.

  5. Determination of trace levels of aquaculture chemotherapeutants in seawater samples by SPME-GC-MS/MS.

    PubMed

    García-Rodríguez, Diego; Carro, Antonia M; Lorenzo, Rosa A; Fernández, Fátima; Cela, Rafael

    2008-08-01

    A sensitive and efficient solid-phase microextraction (SPME) method for the determination of organophosphorous (OPPs) and pyrethroid pesticides (Pyrs) in aquaculture-seawater samples by using GC with MS/MS (GC-MS/MS) was developed. Dichlorvos and chlorpyrifos (OPPs); permethrin, alpha-cypermethrin and deltamethrin (Pyrs) were selected according to their use as chemotherapeutants in the aquaculture industry. Different parameters affecting extraction efficiency such as fibre coating, agitation, pH and extraction time profiles were investigated. An experimental central composite design (alpha = 1) and desirability functions were used for the simultaneous optimization of extraction temperature and sample volume. Finally, a method based on direct SPME in 40 min at 75 degrees C using 100-microm-thick poly(dimethyl)siloxane (PDMS) fibre and 20 mL of sample volume is proposed. The method was validated, exhibiting good linearity, precision and accuracy parameters with picogram per millilitre LODs. The proposed methodology was applied to determine the ultratrace levels of OPPs and Pyrs in aquaculture-seawater samples by the standard addition approach, which proved to be reliable and sensitive, in addition to requiring only small amounts of sample.

  6. Multimycotoxin UPLC-MS/MS for tea, herbal infusions and the derived drinkable products.

    PubMed

    Monbaliu, Sofie; Wu, Aibo; Zhang, Dabing; Van Peteghem, Carlos; De Saeger, Sarah

    2010-12-22

    In recent years the consumption of tea and herbal infusions has increased. These hot drinks are consumed as daily drinks as well as for medicinal purposes. All tea varieties (white, yellow, green, oolong, black and puerh) originate from the leaves of the tea plant, Camellia sinensis. All extracts made of plant or herbal materials which do not contain Camellia sinensis are referred as herbal infusions or tisanes. During processing and manufacturing fungal contamination of the plant materials is possible, enabling contamination of these products with mycotoxins. In this study a multimycotoxin UPLC-MS/MS method was developed and validated for the analysis of the raw tea and herbal infusion materials as well as for their drinkable products. The samples were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), with a mobile phase consisting of variable mixtures of water and methanol with 0.3% formic acid. The limits of detection for the different mycotoxins varied between 2.1 μg/kg and 121 μg/kg for raw materials and between 0.4 μg/L and 46 μg/L for drinkable products. Afterward 91 different tea and herbal infusion samples were analyzed. Only in one sample, Ceylon melange, 76 μg/kg fumonisin B(1) was detected. No mycotoxins were detected in the drinkable products.

  7. The determination of haloacetic acids in real world samples using IC-ESI-MS-MS.

    PubMed

    Slingsby, Rosanne; Saini, Charanjit; Pohl, Christopher

    2009-08-01

    This paper presents the determination of nine haloacetic acids (HAAs) in high ionic strength, treated effluent waters using an ion chromatography-electrospray ionization-tandem mass spectrometry (IC-ESI-MS-MS) method with internal standards and discussions of each of the method parameters. Data is also provided for these same samples using USEPA Method 552.2. The sample matrices contain up to 170 mg/L chloride and 243 mg/L sulfate. Matrix ions are separated from the analytes using a high capacity anion exchange analytical column and diverted to a waste stream during each analysis to avoid signal suppression and contamination of the detector. No derivatization, offline matrix elimination, or preconcentration is used. Four isotopically-labeled HAAs are used for quantification, and detection limits are in the range of 400-1000 microg/L with R(2) of at least 0.997 over two orders of magnitude for all analytes in matrix. A trichloroacetic acid (TCAA) internal standard with the label on the alpha carbon is found to be more stable than the TCAA-1-(13)C. Amounts found using IC-MS-MS are 65-130% of amounts found using Method 552.2 for all analytes in the real world treated effluent waters. Detection limits for all nine analytes in matrix are in the range of 100-700 ng/L.

  8. Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA) in Milk

    PubMed Central

    Andjelkovic, Mirjana; Tsilia, Varvara; Rajkovic, Andreja; De Cremer, Koen; Van Loco, Joris

    2016-01-01

    Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs) in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS) based on multiple reaction monitoring (MRM) was used to detect and quantify two types of SE (A and B) spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively. PMID:27104569

  9. Simultaneous assessment of endogenous thiol compounds by LC-MS/MS.

    PubMed

    Sun, Yao; Yao, Tong; Guo, Xiucai; Peng, Ying; Zheng, Jiang

    2016-09-01

    Biological thiol compounds are very important molecules that participate in various physiological events. Alteration in levels of endogenous thiols has been suggested as a biomarker of early stage of pathological changes. We reported a chemical derivatization- and LC-MS/MS-based approach to simultaneously determine thiol compounds including glutathione (GSH), cysteine (Cys), N-acetyl cysteine (NAC), homocysteine (Hcy), and cysteinylglycine (CysGly) in biological samples. Thiol-containing samples were derivatized with monobromobimane (mBrB) at room temperature, followed by LC-MS/MS analysis. Assessment of the analytes with baseline separation was completed within 10min, using a gradient elution on a C18 reversed-phase column. Excellent linearity was observed for all analytes over their concentration ranges of 1-400μM. The lowest limits of detection (S/N=3) in a range from 0.31fmol (for NAC) to 4.98fmol (for CysGly) were achieved. The results indicate that this approach was sensitive, selective, and well suited for high-throughput quantitative determination of the biological thiols.

  10. Girard derivatization for LC-MS/MS profiling of endogenous ecdysteroids in Drosophila[S

    PubMed Central

    Lavrynenko, Oksana; Nedielkov, Ruslan; Möller, Heiko M.; Shevchenko, Andrej

    2013-01-01

    Ecdysteroids are potent developmental regulators that control molting, reproduction, and stress response in arthropods. In developing larvae, picogram quantities of individual ecdysteroids and their conjugated forms are present along with milligrams of structural and energy storage lipids. To enhance the specificity and sensitivity of ecdysteroid detection, we targeted the 6-ketone group, which is common to all ecdysteroids, with Girard reagents. Unlike other ketosteroids, during the reaction, Girard hydrazones of ecdysteroids eliminated the C14-hydroxyl group, creating an additional C14-C15 double bond. Dehydrated hydrazones of endogenous ecdysteroids were detected by LC-MS/MS in the multiple reaction monitoring (MRM) mode using two mass transitions: one relied upon neutral loss of a quaternary amine from the Girard T moiety; another complementary transition followed neutral loss of the hydrocarbon chain upon C20-C27 cleavage. We further demonstrated that a combination of Girard derivatization and LC-MS/MS enabled unequivocal detection of three major endogenous hormones at the picogram level in an extract from a single Drosophila pupa. PMID:23843360

  11. LC-MS/MS Identification of a Bromelain Peptide Biomarker from Ananas comosus Merr

    PubMed Central

    Secor, Eric R.; Szczepanek, Steven M.; Singh, Anurag; Guernsey, Linda; Natarajan, Prabitha; Rezaul, Karim; Han, David K.; Thrall, Roger S.; Silbart, Lawrence K.

    2012-01-01

    Bromelain (Br) is a cysteine peptidase (GenBank AEH26024.1) from pineapple, with over 40 years of clinical use. The constituents mediating its anti-inflammatory activity are not thoroughly characterized and no peptide biomarker exists. Our objective is to characterize Br raw material and identify peptides in the plasma of Br treated mice. After SDS-PAGE in-gel digestion, Br (VN#3507; Middletown, CT, USA) peptides were analyzed via LC/MS/MS using 95% protein probability, 95% peptide probability, and a minimum peptide number = 5. Br spiked mouse plasma (1 ug/ul) and plasma from i.p. treated mice (12 mg/kg) were assessed using SRM. In Br raw material, we identified seven proteins: four proteases, one jacalin-like lectin, and two protease inhibitors. In Br spiked mouse plasma, six proteins (ananain, bromelain inhibitor, cysteine proteinase AN11, FB1035 precursor, FBSB precursor, and jacalin-like lectin) were identified. Using LC/MS/MS, we identified the unique peptide, DYGAVNEVK, derived from FB1035, in the plasma of i.p. Br treated mice. The spectral count of this peptide peaked at 6 hrs and was undetectable by 24 hrs. In this study, a novel Br peptide was identified in the plasma of treated mice for the first time. This Br peptide could serve as a biomarker to standardize the therapeutic dose and maximize clinical utility. PMID:23082082

  12. Identification of hormone esters in injection site in muscle tissues by LC/MS/MS.

    PubMed

    Costain, R M; Fesser, A C E; McKenzie, D; Mizuno, M; MacNeil, J D

    2008-12-01

    The detection of hormone abuse for growth promotion in food animal production is a global concern. Initial testing for hormones in Canada was directed at the compounds approved for use in beef cattle, melengestrol acetate, trenbolone acetate and zeranol, and the banned compound diethylstilbestrol (DES). No hormonal growth promoters are approved for use in veal production in Canada. However, instances of use of trenbolone and clenbuterol were detected in Canada in the 1990s. During the development of a new analytical method for testosterone and progesterone, there were reports of suspicious injection sites being found in veal calves. Upon implementation of the method, analysis of investigative samples revealed significant residues of testosterone in some injection sites. To prove that the source of these residues was exogenous, a fully validated method for hormone esters was developed to confirm the presence of exogenous hormones in these injection sites. The QUECHERS model was employed in methods development and resulted in a simple, effective extraction technique that consisted of sample pre-homogenization, liquid/liquid partitioning, extract dilution, filtration and use of LC/MS/MS to provide detection selectivity. The result was an adaptable MS/MS confirmation technique that meets the needs of Canadian regulatory authorities to confirm the misuse of injectable testosterone, and potentially other hormones, in food animal production.

  13. Multiclass determination and confirmation of antibiotic residues in honey using LC-MS/MS.

    PubMed

    Lopez, Mayda I; Pettis, Jeffery S; Smith, I Barton; Chu, Pak-Sin

    2008-03-12

    A multiclass method has been developed for the determination and confirmation in honey of tetracyclines (chlortetracycline, doxycycline, oxytetracycline, and tetracycline), fluoroquinolones (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, and sarafloxacin), macrolides (tylosin), lincosamides (lincomycin), aminoglycosides (streptomycin), sulfonamides (sulfathiazole), phenicols (chloramphenicol), and fumagillin residues using liquid chromatography tandem mass spectrometry (LC-MS/MS). Erythromycin (a macrolide) and monensin (an ionophore) can be detected and confirmed but not quantitated. Honey samples (approximately 2 g) are dissolved in 10 mL of water and centrifuged. An aliquot of the supernatant is used to determine streptomycin. The remaining supernatant is filtered through a fine-mesh nylon fabric and cleaned up by solid phase extraction. After solvent evaporation and sample reconstitution, 15 antibiotics are assayed by LC-MS/MS using electrospray ionization (ESI) in positive ion mode. Afterward, chloramphenicol is assayed using ESI in negative ion mode. The method has been validated at the low part per billion levels for most of the drugs with accuracies between 65 and 104% and coefficients of variation less than 17%. The evaluation of matrix effects caused by honey of different floral origin is presented.

  14. MALDI MSI and LC-MS/MS: Towards preclinical determination of the neurotoxic potential of fluoroquinolones.

    PubMed

    Shobo, Adeola; Baijnath, Sooraj; Bratkowska, Dominika; Naiker, Suhashni; Somboro, Anou M; Bester, Linda A; Singh, Sanil D; Naicker, Tricia; Kruger, Hendrik G; Govender, Thavendran

    2016-08-01

    Fluoroquinolones are broad-spectrum antibiotics with efficacy against a wide range of pathogenic microbes associated with respiratory and meningeal infections. The potential toxicity of this class of chemical agents is a source of major concern and is becoming a global issue. The aim of this study was to develop a method for the brain distribution and the pharmacokinetic profile of gatifloxacin in healthy Sprague-Dawley rats, via Multicenter matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) and quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS). We developed a sensitive LC-MS/MS method to quantify gatifloxacin in plasma, lung, and brain homogenates. A pharmacokinetic profile was observed where there is a double peak pattern; a sharp initial increase in the concentration soon after dosing followed by a steady decline until another increase in concentration after a longer period post dosing in all three biological samples was observed. The imaging results showed the drug gradually entering the brain via the blood brain barrier and into the cortical regions from 15 to 240 min post dose. As time elapses, the drug leaves the brain following the same path as it followed on its entry and finally concentrates at the cortex. Copyright © 2015 John Wiley & Sons, Ltd.

  15. LC/MS/MS for identification of in vivo and in vitro metabolites of jatrorrhizine.

    PubMed

    Zhang, Yi; Wu, Wenhua; Han, Fengmei; Chen, Yong

    2008-12-01

    The in vivo and in vitro metabolism of jatrorrhizine has been investigated using a specific and sensitive LC/MS/MS method. In vivo samples including rat feces, urine and plasma collected separately after dosing healthy rats with jatrorrhizine (34 mg/kg) orally, along with in vitro samples prepared by incubating jatrorrhizine with rat intestinal flora and liver microsome, respectively, were purified using a C(18) solid-phase extraction cartridge. The purified samples were then separated with a reversed-phase C(18) column with methanol-formic acid aqueous solution (70:30, v/v, pH3.5) as mobile phase and detected by on-line MS/MS. The structural elucidation of the metabolites was performed by comparing their molecular weights and product ions with those of the parent drug. As a result, seven new metabolites were found in rat urine, 13 metabolites were detected in rat feces, 11 metabolites were detected in rat plasma, 17 metabolites were identified in intestinal flora incubation solution and nine metabolites were detected in liver microsome incubation solution. The main biotransformation reactions of jatrorrhizine were the hydroxylation reaction, the methylation reaction, the demethylation reaction and the dehydrogenation reaction of parent drug and its relative metabolites. All the results were reported for the first time, except for some of the metabolites in rat urine.

  16. Rapid analysis of Listeria monocytogenes cell wall teichoic acid carbohydrates by ESI-MS/MS.

    PubMed

    Eugster, Marcel R; Loessner, Martin J

    2011-01-01

    We report the application of electrospray ionization (ESI) mass spectrometry for compositional characterization of wall teichoic acids (WTA), a major component of gram-positive bacterial cell walls. Tandem mass spectrometry (ESI-MS/MS) of purified and chemically hydrolyzed monomeric WTA components provided sufficient information to identify WTA monomers and their specific carbohydrate constituents. A lithium matrix was used for ionization of uncharged WTA monomers, and successfully applied to analyze the WTA molecules of four Listeria strains differing in carbohydrate substitution on a conserved polyribitol-phosphate backbone structure. Carbohydrate residues such as N-acetylglucosamine or rhamnose linked to the WTA could directly be identified by ESI-MS/MS, circumventing the need for quantitative analysis by gas chromatography. The presence of a terminal N-acetylglucosamine residue tethered to the ribitol was confirmed using fluorescently labeled wheat-germ agglutinin. In conclusion, the mass spectrometry method described here will greatly facilitate compositional analysis and characterization of teichoic acids and similar macromolecules from diverse bacterial species, and represents a significant advance in the identification of serovar-specific carbohydrates and sugar molecules on bacteria.

  17. UP-HILIC-MS/MS to Determine the Action Pattern of Penicillium sp. Dextranase

    NASA Astrophysics Data System (ADS)

    Yi, Lin; Sun, Xue; Du, Kenze; Ouyang, Yilan; Wu, Chengling; Xu, Naiyu; Linhardt, Robert J.; Zhang, Zhenqing

    2015-07-01

    Investigation of the action pattern of enzymes acting on carbohydrates is challenging, as both the substrate and the digestion products are complex mixtures. Dextran and its enzyme-derived oligosaccharides are widely used for many industrial applications. In this work, a new method relying on ultra-performance hydrophilic interaction liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UP-HILIC- Q/TOF-MS/MS) was developed to analyze a complex mixture of dextran oligosaccharide products to determine the action pattern of dextranase. No derivatization of oligosaccharides was required and the impact of the α- and β-configurations of the native oligosaccharides on the chromatographic separation was eliminated. The 1→6, 1→3, 1→4 backbone linkages and the branch linkages of these oligosaccharides were all distinguished from diagnostic ions in their MS/MS spectra, including fragments corresponding to 0,2A, 0,3A, 0,4A, B-H2O, 2,5A, and 3,5A. The sequences of the oligosaccharide products were similarly established. Thus, the complex oligosaccharide mixtures in dextran digestion products were profiled and identified using this method. The more enzyme-resistant structures in dextran were established using much less sample, labor, time, and uncertainty than in previous studies. This method provides an efficient, sensitive, and straightforward way to monitor the entire process of digestion, establish the action pattern of the dextranase from Penicillium sp., and to support the proper industrial application of dextranase.

  18. Annotation of Different Dehydrocatechin Oligomers by MS/MS and Their Occurrence in Black Tea.

    PubMed

    Verloop, Annewieke J W; Gruppen, Harry; Vincken, Jean-Paul

    2016-08-03

    Dehydrocatechins (DhC's), oligomeric oxidation products of (epi)catechins, were formed in model incubations of epicatechin with mushroom tyrosinase. DhC oligomers up to tetramers were detected by reversed-phase ultrahigh-performance liquid chromatography mass spectrometry (RP-UHPLC-MS) analysis. Measurements with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) showed formation of oligomers up to at least 15 catechin subunits. Isomeric DhC's were obtained, and a method based on MS(2) fragment ratios was set up to distinguish between the different interflavanic configurations of the isomers. In the model incubation, 8 dehydrodicatechins (DhC2's) and 22 dehydrotricatechins (DhC3's) were tentatively annotated by their MS(2) signature fragments. Three different interflavanic configuration types were determined for the DhC2's. DhC2's and DhC3's were shown to occur in a black tea extract for the first time. For the DhC2's, at least two isomeric types, i.e., DhC β and DhC ε, could be annotated in black tea.

  19. Global metabolite profiling of human colorectal cancer xenografts in mice using HPLC-MS/MS.

    PubMed

    Loftus, Neil J; Lai, Lindsay; Wilkinson, Robert W; Odedra, Rajesh; Wilson, Ian D; Barnes, Alan J

    2013-06-07

    Reversed-phase gradient LC-MS was used to perform untargeted metabonomic analysis on extracts of human colorectal cancer (CRC) cell lines (COLO 205, HT-29, HCT 116 and SW620) subcutaneously implanted into age-matched athymic nude male mice to study small molecule metabolic profiles and examine possible correlations with human cancer biopsies. Following high mass accuracy data analysis using MS and MS/MS, metabolites were identified by searching against major metabolite databases including METLIN, MASSBANK, The Human Metabolome Database, PubChem, Biospider, LipidMaps and KEGG. HT-29 and COLO 205 tumor xenografts showed a distribution of metabolites that differed from SW620 and HCT 116 xenografts (predominantly on the basis of relative differences in the amounts of amino acids and lipids detected). This finding is consistent with NMR-based analysis of human colorectal tissue, where the metabolite profiles of HT-29 tumors exhibit the greatest similarity to human rectal cancer tissue with respect to changes in the relative amounts of lipids and choline-containing compounds. As the metabolic signatures of cancer cells result from oncogene-directed metabolic reprogramming, the HT-29 xenografts in mice may prove to be a useful model to further study the tumor microenvironment and cancer biology.

  20. Simultaneous inhibition assay for human and microbial kinases via MALDI-MS/MS.

    PubMed

    Smith, Anne Marie E; Brennan, John D

    2014-03-03

    Selective inhibition of one kinase over another is a critical issue in drug development. For antimicrobial development, it is particularly important to selectively inhibit bacterial kinases, which can phosphorylate antimicrobial compounds such as aminoglycosides, without affecting human kinases. Previous work from our group showed the development of a MALDI-MS/MS assay for the detection of small molecule modulators of the bacterial aminoglycoside kinase APH3'IIIa. Herein, we demonstrate the development of an enhanced kinase MALDI-MS/MS assay involving simultaneous assaying of two kinase reactions, one for APH3'IIIa, and the other for human protein kinase A (PKA), which leads to an output that provides direct information on selectivity and mechanism of action. Specificity of the respective enzyme substrates were verified, and the assay was validated through generation of Z'-factors of 0.55 for APH3'IIIa with kanamycin and 0.60 for PKA with kemptide. The assay was used to simultaneously screen a kinase-directed library of mixtures of ten compounds each against both enzymes, leading to the identification of selective inhibitors for each enzyme as well as one non-selective inhibitor following mixture deconvolution.

  1. Quantitation of amphetamine-type stimulants by LC-MS/MS.

    PubMed

    Middleberg, Robert A; Homan, Joseph

    2012-01-01

    Amphetamines or amphetamine-type stimulants (ATSs) refer to a group of pharmacological and -toxicological agents that have a common phenethylamine structural backbone and typically impart effects that include, but are not limited to, vasoconstriction, anorexia, central nervous system stimulation, and/or hallucinations. While differences in side chain chemistry can impart different pharmacological or toxicological effects, for some compounds, e.g., MDMA (Ecstasy), alterations of the phenyl part of the molecule impart other significant effects. ATSs are used both therapeutically and recreationally, with significant abuse and addiction potential. Therapeutically, these agents are mainly used to treat hyperactivity disorders or aid in weight loss. Toxicological effects include hypertension, arrhythmia, excitability, aggressiveness, psychoses, coma, and death.Traditional analytical methods to analyze amphetamines include gas chromatography-mass spectrometry where derivatization is often required to facilitate analysis. Besides sample preparation issues, it has been demonstrated that injection port chemistry in the GC can lead to misleading results with some members of the amphetamine class. To circumvent these issues, liquid chromatography-mass spectrometry (LC-MS/MS) offers the promise of a simpler sample preparation procedure and fewer analytical concerns. This chapter describes an LC-MS/MS technique for the analysis of 14 ATSs in blood, serum/plasma, and urine. The method is quantitative and has reporting limits in the low ng/mL range. Electrospray ionization is used in the positive ion mode. Two transitions for each compound are monitored along with ion ratios.

  2. LC-MS/MS Identification of a Bromelain Peptide Biomarker from Ananas comosus Merr.

    PubMed

    Secor, Eric R; Szczepanek, Steven M; Singh, Anurag; Guernsey, Linda; Natarajan, Prabitha; Rezaul, Karim; Han, David K; Thrall, Roger S; Silbart, Lawrence K

    2012-01-01

    Bromelain (Br) is a cysteine peptidase (GenBank AEH26024.1) from pineapple, with over 40 years of clinical use. The constituents mediating its anti-inflammatory activity are not thoroughly characterized and no peptide biomarker exists. Our objective is to characterize Br raw material and identify peptides in the plasma of Br treated mice. After SDS-PAGE in-gel digestion, Br (VN#3507; Middletown, CT, USA) peptides were analyzed via LC/MS/MS using 95% protein probability, 95% peptide probability, and a minimum peptide number = 5. Br spiked mouse plasma (1 ug/ul) and plasma from i.p. treated mice (12 mg/kg) were assessed using SRM. In Br raw material, we identified seven proteins: four proteases, one jacalin-like lectin, and two protease inhibitors. In Br spiked mouse plasma, six proteins (ananain, bromelain inhibitor, cysteine proteinase AN11, FB1035 precursor, FBSB precursor, and jacalin-like lectin) were identified. Using LC/MS/MS, we identified the unique peptide, DYGAVNEVK, derived from FB1035, in the plasma of i.p. Br treated mice. The spectral count of this peptide peaked at 6 hrs and was undetectable by 24 hrs. In this study, a novel Br peptide was identified in the plasma of treated mice for the first time. This Br peptide could serve as a biomarker to standardize the therapeutic dose and maximize clinical utility.

  3. Detection and validated quantification of toxic alkaloids in human blood plasma--comparison of LC-APCI-MS with LC-ESI-MS/MS.

    PubMed

    Beyer, Jochen; Peters, Frank T; Kraemer, Thomas; Maurer, Hans H

    2007-05-01

    Poisonings with toxic plants may occur after abuse, intentional or accidental ingestion of plants. For diagnosis of such poisonings, multianalyte procedures were developed for detection and validated quantification of the toxic alkaloids aconitine, atropine, colchicine, coniine, cytisine, nicotine and its metabolite cotinine, physostigmine, and scopolamine in plasma using LC-APCI-MS and LC-ESI-MS/MS. After mixed-mode solid-phase extraction of 1 ml of plasma, the analytes were separated using a C8 base select separation column and gradient elution (acetonitrile/ammonium formate, pH 3.5). Calibration curves were used for quantification with cotinine-d(3), benzoylecgonine-d(3), and trimipramine-d(3) as internal standards. The method was validated according to international guidelines. Both assays were selective for the tested compounds. No instability was observed after repeated freezing and thawing or in processed samples. The assays were linear for coniine, cytisine, nicotine and its metabolite cotinine, from 50 to 1000 ng/ml using LC-APCI-MS and 1 to 1000 ng/ml using LC-ESI-MS/MS, respectively, and for aconitine, atropine, colchicine, physostigmine, and scopolamine from 5 to 100 ng/ml for LC-APCI-MS and 0.1 to 100 ng/ml for LC-ESI-MS/MS, respectively. Accuracy ranged from -38.6 to 14.0%, repeatability from 2.5 to 13.5%, and intermediate precision from 4.8 to 13.5% using LC-APCI-MS and from -38.3 to 8.3% for accuracy, from 3.5 to 13.8%, for repeatability, and from 4.3 to 14.7% for intermediate precision using LC-ESI-MS/MS. The lower limit of quantification was fixed at the lowest calibrator in the linearity experiments. With the exception of the greater sensitivity and higher identification power, LC-ESI-MS/MS had no major advantages over LC-APCI-MS. Both presented assays were applicable for sensitive detection of all studied analytes and for accurate and precise quantification, with the exception of the rather volatile nicotine. The applicability of the assays was

  4. Applications of LC/ESI-MS/MS and UHPLC QqTOF MS for the determination of 148 pesticides in fruits and vegetables.

    PubMed

    Wang, Jian; Chow, Willis; Leung, Daniel

    2010-02-01

    This paper presented the applications of liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and ultra-high-pressure liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC QqTOF MS) for the determination of 148 pesticides in fruits and vegetables. Pesticides were extracted from fruits and vegetables using a buffered QuEChERS method. Quantification was achieved using matrix-matched standard calibration curves with isotopically labeled standards or a chemical analog as internal standards in an analytical range from 5 to 500 microg/kg. The method performance parameters including overall recovery, intermediate precision, and measurement uncertainty were evaluated according to a statistically designed experiment, i.e., a nested design. For LC/ESI-MS/MS, 95% of the pesticides had recoveries between 81% and 110%; 97% had an intermediate precision < or = 20%; and 95% (in fruits) or 93% (in vegetables) showed measurement uncertainty < or = 40%. Compared to LC/ESI-MS/MS, UHPLC QqTOF MS showed a relatively poor repeatability and large measurement uncertainty. About 93% (in fruits) or 94% (in vegetables) of the pesticides had recoveries between 81% and 110%; 86% (in fruits) or 90% (in vegetables) had an intermediate precision < or = 20%; and 79% (in fruits) or 88% (in vegetables) showed measurement uncertainty < or = 40%. LC/ESI-MS/MS proved to be the first choice for quantification or pre-target analysis due to its superior sensitivity and good repeatability. UHPLC QqTOF MS provided accurate mass measurement and isotopic patterns, and was an ideal tool for post-target screening and confirmation.

  5. Outdoor and indoor benzene evaluation by GC-FID and GC-MS/MS.

    PubMed

    Sousa, José A; Domingues, Valentina F; Rosas, Mónica S; Ribeiro, Susana O; Alvim-Ferraz, Conceiçao M; Delerue-Matos, Cristina F

    2011-01-01

    The evaluation of benzene in different environments such as indoor (with and without tobacco smoke), a city area, countryside, gas stations and near exhaust pipes from cars running on different types of fuels was performed. The samples were analyzed using gas chromatography (GC) with flame ionization detection (FID) and tandem mass spectrometric detection (MS/MS) (to confirm the identification of benzene in the air samples). Operating conditions for the GC-MS analysis were optimized as well as the sampling and sample preparation. The results obtained in this work indicate that i) the type of fuel directly influences the benzene concentration in the air. Gasoline with additives provided the highest amount of benzene followed by unleaded gasoline and diesel; ii) the benzene concentration in the gas station was always higher than the advisable limit established by law (5 μg m⁻³) and during the unloading of gasoline the achieved concentration was 8371 μg m⁻³; iii) the data from the countryside (Taliscas) and the urban city (Matosinhos) were below 5 μg m⁻³ except 5 days after a fire on a petroleum refinery plant located near the city; iv) it was proven that in coffee shops where smoking is allowed the benzene concentration is higher (6 μg m⁻³) than in coffee shops where this is forbidden (4 μg m⁻³). This method may also be helpful for environmental analytical chemists who use GC-MS/MS for the confirmation or/and quantification of benzene.

  6. Aqueous Organometal Speciation by GC-ICP-MS and HPLC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Hannigan, R.

    2005-12-01

    Organometals, specifically organomercury, organotin and organolead, may only account for a small fraction of the total metal load in aquatic systems. Despite their lower relative abundance, organometal species may have a larger impact on the environment. Although biogeochemical studies of mercury, tin, and to a lesser degree lead, have been done, little is known about the transport and transformation of these organometals in the water column and, more specifically, at the sediment-water interface. Our knowledge is limited, in part, by the lack of instrumental techniques that provide simultaneous highly precise data about the metal species and binding ligand. We have developed a series of hyphenated techniques that allow for precise quantification of the elemental and organic forms of these metals. Most importantly these methods remove sample pre-treatment from the methods though headspace trap desorption, split injection and sequential chromatography with split detection providing detailed information about the metals and organics in stream water samples. Our data show that using headspace trap GC-ICP-MS it is possible to by-pass chromatographic separation of the species and detect elemental, dimethyl and methyl mercury in a single sample from a single injection. Additional research shows that GC-ICP-MS and HPLC-ICP-MS speciation of organotins provide differential speciation data with GC-ICP-MS detecting, at very low concentrations, butylins and HPLC-ICP-MS detecting, at very low concentrations, ethyltins. Integration of these techniques into a single system will eventually lead to a system which provides simultaneous detection of metals and organic binding ligands in a single sample.

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

    PubMed

    Jakobsson, Gerd; Kronstrand, Robert

    2014-06-01

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

  8. Computer-aided tracking of MS lesions

    NASA Astrophysics Data System (ADS)

    Sturm, Deborah; Gurwitz Kletenik, Devorah; Koshy, Philip

    2011-03-01

    Multiple Sclerosis (MS) lesions are known to change over time. The location, size and shape characteristics of lesions are often used to diagnose and to track disease progression. We have improved our lesion-browsing tool that allows users to automatically locate successive significant lesions in a MRI stack. In addition, an automatic alignment feature was implemented to facilitate comparisons across stacks. A lesion stack is formed that can be browsed independently or in tandem with the image windows. Lesions of interest can then be measured, rendered and rotated. Multiple windows allow the viewer to compare the size and shape of lesions from the MRI images of the same patient taken at different time intervals.

  9. Direct sampling MS for environmental screening

    SciTech Connect

    Wise, M.B.; Guerin, M.R.

    1997-01-01

    Decades of improper storage and disposal of hazardous materials by government and industry have resulted in =40,000 contaminated sites that will require cleanup by state and federal agencies. Almost 1,300 of these sites are classified as especially serious threats and are listed on the Superfund National Priorities List (NPL) for accelerated remediation; by 2020, it is estimated that the number of NPL sites will exceed 3,000. Given that an average of 10 years is required to clean up a superfund site, remediation of known hazardous sites will continue well into the next century. Cost projections for environmental restoration range from nearly $200 billion to more than $2 trillion. DSMS is a simple technique that provides real-time response, high sample throughput, and ppb detection limits at low cost. This paper discusses screening methods and direct sampling MS (DSMS) for more cost-effective and efficient environmental characterization. 18 refs., 2 figs., 1 tab.

  10. Semi-automated tandem mass spectrometric (MS/MS) triple quadrupole operating parameter optimization for high-throughput MS/MS detection workflows.

    PubMed

    Geddes, Kristin; Adamson, Gary; Dube, Neal; Crathern, Susan; King, Richard C

    2009-05-01

    This paper describes an automated workflow for the determination of selected reaction monitoring (SRM) transitions and optimum mass spectrometric (MS) instrument parameters. The approach uses a Nanomate from Advion Biosciences for automated infusion of small amounts of sample in combination with Automaton optimization software from Sciex. The results are stored in the Analyst software Compound Database for automated acquisition method building. Comparisons are presented between the more traditional optimization methods of manual flow injection optimization, Autotune infusion optimization, Automaton flow injection optimization and the Nanomate-Automaton optimization approach. Data is also presented to show that acquisition methods developed on the Sciex model API3000 instrument can be effectively transferred to the Sceix API4000 and API5000 model instruments.

  11. Characterization of wine with PTR-MS

    NASA Astrophysics Data System (ADS)

    Boscaini, Elena; Mikoviny, Tomas; Wisthaler, Armin; Hartungen, Eugen Von; Märk, Tilmann D.

    2004-12-01

    A new method for measuring volatile profiles of alcoholic beverages (or other ethanol-containing analytes such as perfumes or herbs) has been developed. The method is based on proton transfer reaction mass spectrometry (PTR-MS). However, instead of hydronium ions (H3O+) protonated ethanol clusters (C2H5OH2+(C2H5OH)n = 1,2) are used as chemical ionization reagent ions. A stable reagent ion distribution is obtained by a 10-fold dilution of analyte headspace into ethanol-saturated nitrogen. Samples with different ethanol content can thus be directly compared. Characteristic mass spectral fingerprints have been obtained for four wine varieties. Principal component analysis discriminates between different wine varieties and shows specific correlations between wine variety and selected ions.

  12. Quantitation of Melatonin and N-acetylserotonin in Human Plasma by Nanoflow LC-MS/MS and Electrospray LC-MS/MS

    PubMed Central

    Carter, Melissa D.; Calcutt, M. Wade; Malow, Beth A.; Rose, Kristie L.; Hachey, David L.

    2012-01-01

    Melatonin (MEL) and its chemical precursor N-acetylserotonin (NAS) are believed to be potential biomarkers for sleep-related disorders. Measurement of these compounds, however, has proven to be difficult due to their low circulating levels, especially that of NAS. Few methods offer the sensitivity, specificity and dynamic range needed to monitor MEL and its precursors and metabolites in small blood samples, such as those obtained from pediatric patients. In support of our ongoing study to determine the safety, tolerability, and PK dosing strategies for MEL in treating insomnia in children with autism spectrum disorder, two highly sensitive LC-MS/MS assays were developed for the quantitation of MEL and precursor NAS at pg/mL levels in small volumes of human plasma. A validated electrospray ionization (ESI) method was used to quantitate high levels of MEL in PK studies and a validated nanospray (nESI) method was developed for quantitation of MEL and NAS at endogenous levels. In both assays plasma samples were processed by centrifugal membrane dialysis after addition of stable isotopic internal standards, and the components were separated by either conventional LC using a Waters SymmetryShield RP18 column (2.1×100 mm, 3.5 μm) or on a polyimide-coated, fused-silica capillary self-packed with 17 cm AquaC18 (3 μm, 125 Å). Quantitation was done using the SRM transitions m/z 233→174 and m/z 219→160 for MEL and NAS, respectively. The analytical response ratio vs. concentration curves were linear for MEL (nanoflow LC: 11.7–1165 pg/mL, LC: 1165–116500 pg/mL) and for NAS (nanoflow LC: 11.0–1095 pg/mL). PMID:22431453

  13. Segmental hair analysis for differentiation of tilidine intake from external contamination using LC-ESI-MS/MS and MALDI-MS/MS imaging.

    PubMed

    Poetzsch, Michael; Baumgartner, Markus R; Steuer, Andrea E; Kraemer, Thomas

    2015-02-01

    Segmental hair analysis has been used for monitoring changes of consumption habit of drugs. Contamination from the environment or sweat might cause interpretative problems. For this reason, hair analysis results were compared in hair samples taken 24 h and 30 days after a single tilidine dose. The 24-h hair samples already showed high concentrations of tilidine and nortilidine. Analysis of wash water from sample preparation confirmed external contamination by sweat as reason. The 30-day hair samples were still positive for tilidine in all segments. Negative wash-water analysis proved incorporation from sweat into the hair matrix. Interpretation of a forensic case was requested where two children had been administered tilidine by their nanny and tilidine/nortilidine had been detected in all hair segments, possibly indicating multiple applications. Taking into consideration the results of the present study and of MALDI-MS imaging, a single application as cause for analytical results could no longer be excluded. Interpretation of consumption behaviour of tilidine based on segmental hair analysis has to be done with caution, even after typical wash procedures during sample preparation. External sweat contamination followed by incorporation into the hair matrix can mimic chronic intake. For assessment of external contamination, hair samples should not only be collected several weeks but also one to a few days after intake. MALDI-MS imaging of single hair can be a complementary tool for interpretation. Limitations for interpretation of segmental hair analysis shown here might also be applicable to drugs with comparable physicochemical and pharmacokinetic properties.

  14. Yield of 6,000 proteins by 1D nLC-MS/MS without pre-fractionation.

    PubMed

    Anagnostopoulos, Athanasios K; Stravopodis, Dimitrios J; Tsangaris, George Th

    2017-03-15

    Mass spectrometry (MS) has dominated over other protein analysis methods that aspire to deliver rapid and sensitive protein annotation, due to its ability to acquire high-content biological information from samples of great complexity. Routinely, in-depth analysis of complex biological samples, such as total cell lysates, relies on the high separation power of two-dimensional liquid chromatography-tandem MS (2D LC-MS/MS), often combined with protein pre-fractionation. However, on the basis of recent advances in chromatographic and MS instrumentation, one-dimensional (1D) LC-MS/MS approaches have become the method-of-choice for high-volume/high-throughput protein experiments. Thousands of proteins can be identified in single-run LC-MS/MS experiments. In the present study a 1D LC-MS/MS approach was applied on whole-cell lysates of WM-266-4 human cells leading to identification of more than 5,300 protein groups, 6,000 proteins and 22,00 peptides, in a single run. Using no pre-fractionation steps, method optimization was achieved through experimentation on lysis and protein extraction solutions, as well as nLC gradient parameters.

  15. Aflatoxins contamination in Pakistani brown rice: a comparison of TLC, HPLC, LC-MS/MS and ELISA techniques.

    PubMed

    Iqbal, Javed; Asghar, Muhammad Asif; Ahmed, Aftab; Khan, Mobeen Ahmed; Jamil, Khalid

    2014-12-01

    Advancement in the field of analytical food-chemistry has explored various experimental techniques for aflatoxins (AFs) quantification. The present study was aimed to compare four different techniques; thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA) for the analysis of aflatoxin B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂) in brown rice (n = 120) being collected from Karachi, Pakistan. All the four assays provide precised, accurate and comparable results. However, some differences were observed. For instance, TLC, HPLC and LC-MS/MS methodologies offered the advantage of the quantification of individual toxins in contrast to ELISA technique. The contamination ranges of AFB₁/AFB₂ as determined by TLC, HPLC and LC-MS/MS were 1.18-9.97/0.59-1.52, 0.16-10.54/0.26-1.35 and 0.11-10.88/0.38-1.48 µg/kg, respectively. However, AFG₁ and AFG₂ were not detected in any tested samples. Furthermore, owing to low-detection limit and sensitivity, HPLC and LC-MS/MS methodologies have identified greater number of contaminated samples in comparison to TLC and ELISA techniques. The overall average results of total AFs as provided by HPLC (3.79 µg/kg) and LC-MS/MS (3.89 µg/kg) were found higher in comparison to TLC (3.68 µg/kg) and ELISA (3.70 µg/kg). On the basis of achieved results, it was concluded that TLC, HPLC, LC-MS/MS and ELISA techniques are valuable tool for the quantification of AFs in cereals and grains. Furthermore, HPLC and LC-MS/MS techniques offer an added advantage for the detection of AFs in diminutive levels.

  16. Title: The validation of Cryogenic Laser Ablation ICP-MS (CLA-ICP-MS) methods by comparison to laser ablation (LA)-ICP-MS and solution based ICP-MS methods, for the analysis of metals in biological tissues

    NASA Astrophysics Data System (ADS)

    Hannigan, R.; Darrah, T. H.; Horton, M.

    2009-12-01

    ICP-MS and laser ablation ICP-MS (LA-ICP-MS) are well established techniques for the analysis of metals in geological and environmental samples. LA-ICP-MS is commonly used in geological applications to determine the spatial distribution of metal concentrations at small sampling intervals (as low as 10 microns). However, measurement of metals in water-rich, soft biological tissues typically requires samples to be digested into solutions, obfuscating spatial variations in metal concentrations. The cryogenic cell solidifies (by freezing) soft tissue, allowing these tissues to be analyzed by laser ablation for spatial variations in metal concentration. The cell is temperature programmable and capable of maintaining a sample at any temperature between -35C and 25C throughout prolonged analysis. We validate the cryogenic laser ablation ICP-MS (CLA-ICP-MS) method using NIST Glass SRM 612. We also compare metal concentration data analyzed by cryogenic laser ablation ICP-MS (CLA-ICP-MS), LA-ICP-MS, and solution based ICP-MS, for human and rodent brain samples. The cryogenic laser ablation cell will expand analytical capabilities for measuring spatial distribution and concentration of metals incorporated into biological tissues.

  17. Determination of anabolic-androgenic steroid adulterants in counterfeit drugs by UHPLC-MS/MS.

    PubMed

    Cho, So-Hyun; Park, Hyoung Joon; Lee, Ji Hyun; Do, Jung-Ah; Heo, Seok; Jo, Jeong Hwa; Cho, Sooyeul

    2015-01-01

    Anabolic-androgenic steroids (AASs) have been illegally used in counterfeit drugs to improve the performance of athletes. In addition, AASs have been used for cosmetic purpose by non-athletes. To determine the presence of 26 AASs, an analysis method using ultra-liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. The validated method was applied to 19 counterfeit drugs collected from the Internet and off-line markets during 2014. Nearly 50% (9/19) of the samples contained one of these 26 AASs. In addition, the concentration ranges of the AASs ranged from 0.09 to 119,228.57 mg/kg in the suspected samples. The determined AASs primarily consisted of testosterone and testosterone 17-propionate (26%) followed by boldenone (21%). These results indicate the adulteration of over-the-counter counterfeit drugs, and the continuous monitoring of counterfeit drugs or dubious dietary supplements containing anabolic steroids is warranted.

  18. HPLC-DAD-ESI-MS/MS screening of bioactive components from Rhus coriaria L. (Sumac) fruits.

    PubMed

    Abu-Reidah, Ibrahim M; Ali-Shtayeh, Mohammed S; Jamous, Rana M; Arráez-Román, David; Segura-Carretero, Antonio

    2015-01-01

    Rhus coriaria L. (sumac) is an important crop widely used in the Mediterranean basin as a food spice, and also in folk medicine, due to its health-promoting properties. Phytochemicals present in plant foods are in part responsible for these consequent health benefits. Nevertheless, detailed information on these bioactive compounds is still scarce. Therefore, the present work was aimed at investigating the phytochemical components of sumac fruit epicarp using HPLC-DAD-ESI-MS/MS in two different ionisation modes. The proposed method provided tentative identification of 211 phenolic and other phyto-constituents, most of which have not been described so far in R. coriaria fruits. More than 180 phytochemicals (tannins, (iso)flavonoids, terpenoids, etc.) are reported herein in sumac fruits for the first time. The obtained results highlight the importance of R. coriaria as a promising source of functional ingredients, and boost its potential use in the food and nutraceutical industries.

  19. STS-31 MS McCandless and MS Sullivan during JSC WETF underwater simulation

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This overall view shows STS-31 Mission Specialist (MS) Bruce McCandless II (left) and MS Kathryn D. Sullivan making a practice space walk in JSC's Weightless Environment Training Facility (WETF) Bldg 29 pool. McCandless works with a mockup of the remote manipulator system (RMS) end effector which is attached to a grapple fixture on the Hubble Space Telescope (HST) mockup. Sullivan manipulates HST hardware on the Support System Module (SSM) forward shell. SCUBA-equipped divers monitor the extravehicular mobility unit (EMU) suited crewmembers during this simulated extravehicular activity (EVA). No EVA is planned for the Hubble Space Telescope (HST) deployment, but the duo has trained for contingencies which might arise during the STS-31 mission aboard Discovery, Orbiter Vehicle (OV) 103. Photo taken by NASA JSC photographer Sheri Dunnette.

  20. Building and searching tandem mass (MS/MS) spectral libraries for peptide identification in proteomics.

    PubMed

    Lam, Henry; Aebersold, Ruedi

    2011-08-01

    Spectral library searching is an emerging approach in peptide identifications from tandem mass spectra, a critical step in proteomic data analysis. In spectral library searching, a spectral library is first meticulously compiled from a large collection of previously observed peptide MS/MS spectra that are conclusively assigned to their corresponding amino acid sequence. An unknown spectrum is then identified by comparing it to all the candidates in the spectral library for the most similar match. This review discusses the basic principles of spectral library building and searching, describes its advantages and limitations, and provides a primer for researchers interested in adopting this new approach in their data analysis. It will also discuss the future outlook on the evolution and utility of spectral libraries in the field of proteomics.

  1. Multiresidue determination of triarylmethane and phenothiazine dyes in fish tissues by LC-MS/MS.

    PubMed

    Tarbin, Jonathan A; Chan, Danny; Stubbings, George; Sharman, Matthew

    2008-09-12

    The occurrence of residues of malachite green and its leuco-metabolite in tissues of farmed fish for human consumption have long been of concern and there is extensive literature on methods of analysis and surveillance for these compounds. Recently, concern has been expressed that the use of other related compounds in place of malachite green may go undetected. This paper describes a new method for extending the range of triarylmethane and related phenothiazine dyes that can be detected in fish. In this procedure 13 parent compounds are monitored, with any potential leuco-forms being oxidized back to the parent prior to determination. The method utilizes a buffer-acetonitrile extraction followed by liquid-liquid extraction. Oxidant is added and the extracts further purified by cation exchange chromatography. Final determination is carried out using LC-MS/MS. The method has been validated to the standards of Commission Decision 2002/657/EC.

  2. Determination of phenolic compounds in Yucca gloriosa bark and root by LC-MS/MS.

    PubMed

    Montoro, Paola; Skhirtladze, Alexandre; Bassarello, Carla; Perrone, Angela; Kemertelidze, Ether; Pizza, Cosimo; Piacente, Sonia

    2008-08-05

    On the basis of the biological activities shown by yuccaols and gloriosaols from Yucca schidigera and Yucca gloriosa, the content of yuccaols and gloriosaols in two different parts of Y. gloriosa (roots and bark), was determined for each single compound, and compared with phenolic determination in Y. schidigera bark, concluding that Y. gloriosa bark and roots are rich sources of phenolic derivatives structurally related to resveratrol. LC/ESIMS (liquid chromatography coupled to electrospray mass spectrometry) qualitative and an LC/ESIMS/MS (liquid chromatography coupled to tandem electrospray mass spectrometry) quantitative studies of the phenolic fraction of Y. gloriosa were performed. LC/ESIMS/MS multiple reaction monitoring (MRM) method previously described for yuccaols in Y. schidigera was applied and optimised for separation and determination of gloriosaols and yuccaols in Y. gloriosa. Due to the sensitivity and the repeatability of the assay, we suggest this method as suitable for industrial quality control of raw materials and final products.

  3. Alternative matrices for therapeutic drug monitoring of immunosuppressive agents using LC-MS/MS.

    PubMed

    Ghareeb, Mwlod; Akhlaghi, Fatemeh

    2015-01-01

    Immunosuppressive drugs used in solid organ transplants typically have narrow therapeutic windows and high intra- and intersubject variability. To ensure satisfactory exposure, therapeutic drug monitoring (TDM) plays a pivotal role in any successful posttransplant maintenance therapy. Currently, recommendations for optimum immunosuppressant concentrations are based on blood/plasma measurements. However, they introduce many disadvantages, including poor prediction of allograft survival and toxicity, a weak correlation with drug concentrations at the site of action and the invasive nature of the sample collection. Thus, alternative matrices have been investigated. This paper reviews tandem-mass spectrometry (LC-MS/MS) methods used for the quantification of immunosuppressant drugs utilizing nonconventional matrices, namely oral fluids, fingerprick blood and intracellular and intratissue sampling. The advantages, disadvantages and clinical application of such alternative mediums are discussed. Additionally, sample extraction techniques and basic chromatography information regarding these methods are presented in tabulated form.

  4. Free amino acid profiling in the giant puffball mushroom (Calvatia gigantea) using UPLC-MS/MS.

    PubMed

    Kıvrak, İbrahim; Kıvrak, Şeyda; Harmandar, Mansur

    2014-09-01

    Wild edible and medicinal mushroom, Calvatia gigantea, was quantitatively analyzed for the determination of its free amino acids using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The concentrations of total free amino acids, essential and non-essential amino acids were 199.65 mg/100 g, 113.69 mg/100 g, and 85.96 mg/100 g in C. gigantea, respectively. This study showed that C. gigantea, so called a giant puffball mushroom, has free amino acids content. The essential amino acids: tryptophan, isoleucine, valine, phenylalanine, leucine, threonine, lysine, histidine, methionine, and the non-essential amino acids: tyrosine, 4-hyrdroxy proline, arginine, proline, glycine, serine, alanine, glutamine, glutamic acid, aspargine, aspartic acid were detected.

  5. Lipid Discovery by Combinatorial Screening and Untargeted LC-MS/MS

    PubMed Central

    Bilgin, Mesut; Born, Petra; Fezza, Filomena; Heimes, Michael; Mastrangelo, Nicolina; Wagner, Nicolai; Schultz, Carsten; Maccarrone, Mauro; Eaton, Suzanne; Nadler, André; Wilm, Matthias; Shevchenko, Andrej

    2016-01-01

    We present a method for the systematic identification of picogram quantities of new lipids in total extracts of tissues and fluids. It relies on the modularity of lipid structures and applies all-ions fragmentation LC-MS/MS and Arcadiate software to recognize individual modules originating from the same lipid precursor of known or assumed structure. In this way it alleviates the need to recognize and fragment very low abundant precursors of novel molecules in complex lipid extracts. In a single analysis of rat kidney extract the method identified 58 known and discovered 74 novel endogenous endocannabinoids and endocannabinoid-related molecules, including a novel class of N-acylaspartates that inhibit Hedgehog signaling while having no impact on endocannabinoid receptors. PMID:27312775

  6. Rapid and reproducible determination of active gibberellins in citrus tissues by UPLC/ESI-MS/MS.

    PubMed

    Manzi, Matías; Gómez-Cadenas, Aurelio; Arbona, Vicent

    2015-09-01

    Phytohormone determination is crucial to explain the physiological mechanisms during growth and development. Therefore, rapid and precise methods are needed to achieve reproducible determination of phytohormones. Among many others, gibberellins (GAs) constitute a family of complex analytes as most of them share similar structure and chemical properties although only a few hold biological activity (namely GA1; GA3; GA4 and GA7). A method has been developed to extract GAs from plant tissues by mechanical disruption using ultrapure water as solvent and, in this way, ion suppression was reduced whereas sensitivity increased. Using this methodology, the four active GAs were separated and quantified by UPLC coupled to MS/MS using the isotope-labeled internal standards [(2)H2]-GA1 and [(2)H2]-GA4. To sum up, the new method provides a fast and reproducible protocol to determine bioactive GAs at low concentrations, using minimal amounts of sample and reducing the use of organic solvents.

  7. Contribution to the characterization of Opuntia spp. juices by LC-DAD-ESI-MS/MS.

    PubMed

    Mata, A; Ferreira, J P; Semedo, C; Serra, T; Duarte, C M M; Bronze, M R

    2016-11-01

    Opuntia spp. fruits are considered as health promoting foods due to the diversity of bioactive molecules found in these fruits. The composition in organic acids, flavonols and betalains in the Opuntia ficus-indica juice from a region of Portugal was accomplished for the first time by liquid chromatography and tandem mass spectrometry using an electrospray ionization source operating in negative and positive mode. The methodology used allowed the detection of 44 compounds, from which 32 were identified. Isorhamnetin derivatives were the dominant flavonol glycosides. A total of 9 betalains including 6 betaxanthins and 3 betacyanin were also detected in the fruit juice samples and indicaxanthin, betanin and isobetanin were the major pigments. Phenolic acid and phenylpyruvic acid derivatives were also identified. To our knowledge, it is the first time derivative compounds from piscidic acid, phenolic compounds and betalains are characterized in cactus pear juice using a single LC-DAD-ESI-MS/MS method.

  8. Cetirizine Quantification by High-Performance Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Munar, Ada; Frazee, Clint; Jones, Bridgette; Garg, Uttam

    2016-01-01

    A multiple reaction monitoring (MRM), positive ion electrospray ionization, LC/MS/MS method is described for the quantification of cetirizine. The compound was isolated from human plasma by protein precipitation using acetonitrile. Cetirizine d4 was used as an internal standard. Chromatographic conditions were achieved using a C18 column and a combination of ammonium acetate, water, and methanol as the mobile phase. MRMs were: cetirizine, 389.26 → 165.16, 201.09; cetirizine d4, 393.09 → 165.15, 201.10. Calibration curves were constructed by plotting the peak area ratios of the calibrators' target MRM transition area to labeled internal standard target MRM transition area versus concentration.

  9. Substitution pattern elucidation of hydroxypropyl Pinus pinaster (Ait.) bark polyflavonoid derivatives by ESI(-)-MS/MS.

    PubMed

    García Marrero, Danny E; Glasser, Wolfgang G; Pizzi, Antonio; Paczkowski, Sebastian; Laborie, Marie-Pierre G

    2014-10-01

    The structure of condensed tannins (CTs) from Pinus pinaster bark extract and their hydroxypropylated derivatives with four degrees of substitution (DS 1, 2, 3 and 4) has been characterized for the first time using negative-ion mode electrospray ionization tandem mass spectrometry (ESI(-)-MS/MS). The results showed that P. pinaster bark CTs possess structural homogeneity in terms of monomeric units (C(15), catechin). The oligomer sizes were detected to be dimers to heptamers. The derivatives showed typical phenyl-propyl ether mass fragmentation by substituent elimination (58 amu) and inherent C(15) flavonoid fissions. The relative abundance of the product ions revealed a preferential triple, tetra-/penta- and octa- hydroxypropylation substitution pattern in the monomer, dimer and trimer derivatives, respectively. A defined order of -OH reactivity towards propylene oxide was established by means of multistage experiments (A-ring ≥ B-ring > C-ring). A high structural heterogeneity of the modified oligomers was detected.

  10. Quantitation of sweet steviol glycosides by means of a HILIC-MS/MS-SIDA approach.

    PubMed

    Well, Caroline; Frank, Oliver; Hofmann, Thomas

    2013-11-27

    Meeting the rising consumer demand for natural food ingredients, steviol glycosides, the sweet principle of Stevia rebaudiana Bertoni (Bertoni), have recently been approved as food additives in the European Union. As regulatory constraints require sensitive methods to analyze the sweet-tasting steviol glycosides in foods and beverages, a HILIC-MS/MS method was developed enabling the accurate and reliable quantitation of the major steviol glycosides stevioside, rebaudiosides A-F, steviolbioside, rubusoside, and dulcoside A by using the corresponding deuterated 16,17-dihydrosteviol glycosides as suitable internal standards. This quantitation not only enables the analysis of the individual steviol glycosides in foods and beverages but also can support the optimization of breeding and postharvest downstream processing of Stevia plants to produce preferentially sweet and least bitter tasting Stevia extracts.

  11. Quantitative lipopolysaccharide analysis using HPLC/MS/MS and its combination with the limulus amebocyte lysate assay[S

    PubMed Central

    Pais de Barros, Jean-Paul; Gautier, Thomas; Sali, Wahib; Adrie, Christophe; Choubley, Hélène; Charron, Emilie; Lalande, Caroline; Le Guern, Naig; Deckert, Valérie; Monchi, Mehran; Quenot, Jean-Pierre; Lagrost, Laurent

    2015-01-01

    Quantitation of plasma lipopolysaccharides (LPSs) might be used to document Gram-negative bacterial infection. In the present work, LPS-derived 3-hydroxymyristate was extracted from plasma samples with an organic solvent, separated by reversed phase HPLC, and quantitated by MS/MS. This mass assay was combined with the limulus amebocyte lysate (LAL) bioassay to monitor neutralization of LPS activity in biological samples. The described HPLC/MS/MS method is a reliable, practical, accurate, and sensitive tool to quantitate LPS. The combination of the LAL and HPLC/MS/MS analyses provided new evidence for the intrinsic capacity of plasma lipoproteins and phospholipid transfer protein to neutralize the activity of LPS. In a subset of patients with systemic inflammatory response syndrome, with documented infection but with a negative plasma LAL test, significant amounts of LPS were measured by the HPLC/MS/MS method. Patients with the highest plasma LPS concentration were more severely ill. HPLC/MS/MS is a relevant method to quantitate endotoxin in a sample, to assess the efficacy of LPS neutralization, and to evaluate the proinflammatory potential of LPS in vivo. PMID:26023073

  12. LC-MS/MS Peptide Mapping with Automated Data Processing for Routine Profiling of N-Glycans in Immunoglobulins

    NASA Astrophysics Data System (ADS)

    Shah, Bhavana; Jiang, Xinzhao Grace; Chen, Louise; Zhang, Zhongqi

    2014-06-01

    Protein N-Glycan analysis is traditionally performed by high pH anion exchange chromatography (HPAEC), reversed phase liquid chromatography (RPLC), or hydrophilic interaction liquid chromatography (HILIC) on fluorescence-labeled glycans enzymatically released from the glycoprotein. These methods require time-consuming sample preparations and do not provide site-specific glycosylation information. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) peptide mapping is frequently used for protein structural characterization and, as a bonus, can potentially provide glycan profile on each individual glycosylation site. In this work, a recently developed glycopeptide fragmentation model was used for automated identification, based on their MS/MS, of N-glycopeptides from proteolytic digestion of monoclonal antibodies (mAbs). Experimental conditions were optimized to achieve accurate profiling of glycoforms. Glycan profiles obtained from LC-MS/MS peptide mapping were compared with those obtained from HPAEC, RPLC, and HILIC analyses of released glycans for several mAb molecules. Accuracy, reproducibility, and linearity of the LC-MS/MS peptide mapping method for glycan profiling were evaluated. The LC-MS/MS peptide mapping method with fully automated data analysis requires less sample preparation, provides site-specific information, and may serve as an alternative method for routine profiling of N-glycans on immunoglobulins as well as other glycoproteins with simple N-glycans.

  13. Identification and Quantification of Loline-Type Alkaloids in Endophyte-Infected Grasses by LC-MS/MS.

    PubMed

    Adhikari, Khem B; Boelt, Birte; Fomsgaard, Inge S

    2016-08-10

    Lolines, fungal metabolites of the grass-endophyte association, were identified and quantified using newly developed LC-MS/MS methods in endophyte-infected grasses belonging to the Lolium and Festuca genera after extraction with three different solvents using two extraction methods. The shaking extraction method with isopropanol/water was superior to the other methods due to its high sensitivity, high accuracy (recovery within or close to the range of 80-120%), and high precision (coefficient of variation of <10%). Seven loline alkaloids were identified and quantified using our newly established LC-MS/MS methods, and N-formylloline was the most abundant (5 mg/g dry matter), followed by N-acetylloline. These LC-MS/MS methods used the shortest sample handling time and the fewest sample preparation steps and proved to be good alternatives to existing GC and GC-MS analytical methods without compromising analytical efficiency. In conclusion, we developed for the first time a highly sensitive quantitative LC-MS/MS analytical method for the accurate and reproducible quantification and a LightSight-assisted LC-QTRAP/MS qualitative method for the tentative identification of loline-type alkaloids in endophyte-infected grasses.

  14. The EM Earthquake Precursor

    NASA Astrophysics Data System (ADS)

    Jones, K. B., II; Saxton, P. T.

    2013-12-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

  15. Analysis of biofluids by paper spray MS: advances and challenges.

    PubMed

    Manicke, Nicholas E; Bills, Brandon J; Zhang, Chengsen

    2016-03-01

    Paper spray MS is part of a cohort of ambient ionization or direct analysis methods that seek to analyze complex samples without prior sample preparation. Extraction and electrospray ionization occur directly from the paper substrate upon which a dried matrix spot is stored. Paper spray MS is capable of detecting drugs directly from dried blood, plasma and urine spots at the low ng/ml to pg/ml levels without sample preparation. No front end separation is performed, so MS/MS or high-resolution MS is required. Here, we discuss paper spray methodology, give a comprehensive literature review of the use of paper spray MS for bioanalysis, discuss technological advancements and variations on this technique and discuss some of its limitations.

  16. LC-MS/MS Based Proteomic Analysis and Functional Inference of Hypothetical Proteins in Desulfovibrio Vulgaris

    SciTech Connect

    Zhang, Weiwen; Culley, David E.; Gritsenko, Marina A.; Moore, Ronald J.; Nie, Lei; Scholten, Johannes C.; Petritis, Konstantinos; Strittmatter, Eric F.; Camp, David G.; Smith, Richard D.; Brockman, Fred J.

    2006-11-03

    Direct liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to examine the proteins extracted from Desulfovibrio vulgaris cells. While our previous study provided a proteomic overview of the cellular metabolism based on proteins with known functions (Zhang et al., 2006a, Proteomics, 6: 4286-4299), this study describes the global detection and functional inference for hypothetical D. vulgaris proteins. Across six growth conditions, 15,841 tryptic peptides were identified with high confidence. Using a criterion of peptide identification from at least two out of three independent LC-MS/MS analyses per protein, 176 open reading frames (ORFs) originally annotated as hypothetical proteins were found to encode expressed proteins. These proteins ranged from 6.0 to 153 kDa, and had calculated pI values ranging from 3.7 to 11.5. Based on homology search results (with E value <= 0.01 as a cutoff), 159 proteins were defined as conserved hypothetical proteins, and 17 proteins were unique to the D. vulgaris genome. Functional inference of the conserved hypothetical proteins was performed by a combination of several non-homology based methods: genomic context analysis, phylogenomic profiling, and analysis of a combination of experimental information including peptide detection in cells grown under specific culture conditions and cellular location of the proteins. Using this approach we were able to assign possible functions to 27 conserved hypothetical proteins. This study demonstrated that a combination of proteomics and bioinformatics methodologies can provide verification for the authenticity of hypothetical proteins and improve annotation for the D. vulgaris genome.

  17. Stars of type MS with evidence of white dwarf companions. [IUE, Main Sequence (MS)

    NASA Technical Reports Server (NTRS)

    Peery, Benjamin F., Jr.

    1986-01-01

    A search for white dwarf companions of MS-type stars was conducted, using IUE. The overendowments of these stars in typical S-process nuclides suggest that they, like the Ba II stars, may owe their peculiar compositions to earlier mass transfer. Short-wavelength IUE spectra show striking emission line variability in HD35155, HD61913, and 4 Ori; HD35155 and 4 Ori show evidence of white dwarf companions.

  18. Rapid Multi-Residue Analysis of Pesticides in Pulses by LC-MS/MS.

    PubMed

    Iwakoshi, Keiko; Otsuka, Kenji; Tamura, Yasuhiro; Tomizawa, Sanae; Masubuchi, Tamako; Yamaki, Yumiko; Nakagawa, Yukiko; Masuda, Ryoko; Suto, Shota; Kokaji, Yoshie; Shindo, Tetsuya; Takano, Ichiro

    2016-01-01

    Rapid multi-residue analysis of pesticides in pulses was developed using LC-MS/MS. Pesticide residues in 5 g of homogenized pulses were extracted with 30 mL of acetonitrile and salted out with 4 g of anhydrous magnesium sulfate and 2 g of sodium chloride in the presence of citrate buffer in a disposable tube. The resulting residues were extracted with 30 mL of acetonitrile, and co-extractives were removed on a handmade four-layer column, consisting of a layer of Z-Sep/C18 (20 mg/50 mg) dry particles on top of a three-layer, custom-made (pre-packed) column (lower bed: 60 mg of PSA, middle bed: 30 mg of GC, and top bed: 60 mg of C18) packed in a 10 mm internal diameter polypropylene column (3 mL). The developed method showed good recoveries of pesticides in soybean, lentil, white kidney bean and garbanzo. According to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan, recovery tests were conducted in soybeans fortified with 107 kinds of pesticides at the levels of 0.01 and 0.1 μg/g, respectively. At each concentration 2 samples were extracted on 5 separate days. Pesticides in the test solution were determined by LC-MS/MS using scheduled MRM. As regards the trueness of this method for 107 pesticides in soybeans, 97 pesticides were in the range of 70-120% with satisfactory repeatability and within-run reproducibility. This new method is expected to be applicable for routine examination of pesticide residues in soybeans.

  19. Quantitative determination of vitamin D metabolites in plasma using UHPLC-MS/MS.

    PubMed

    Ding, Shujing; Schoenmakers, Inez; Jones, Kerry; Koulman, Albert; Prentice, Ann; Volmer, Dietrich A

    2010-09-01

    Vitamin D is an important determinant of bone health at all ages. The plasma concentrations of 25-hydroxy vitamin D (25-OH D) and other metabolites are used as biomarkers for vitamin sufficiency and function. To allow for the simultaneous determination of five vitamin D metabolites, 25-OH D(3), 25-OH D(2), 24,25-(OH)(2) D(3), 1,25-(OH)(2) D(3), and 1,25-(OH)(2) D(2), in low volumes of human plasma, an assay using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was established. Plasma samples were spiked with isotope-labeled internal standards and pretreated using protein precipitation, solid-phase extraction (SPE) and a Diels-Alder derivatization step with 4-phenyl-1,2,4-triazoline-3,5-dione. The SPE recovery rates ranged from 55% to 85%, depending on the vitamin D metabolite; the total sample run time was <5 min. Mass spectrometry was conducted using positive ion electrospray ionization in the multiple reaction monitoring mode on a quadrupole-quadrupole-linear ion trap instrument after pre-column addition of methylamine to increase the ionization efficiency. The intra- and inter-day relative standard deviations were 1.6-4.1% and 3.7-6.8%, respectively. The limit of quantitation for these compounds was determined to be between 10 and 20 pg/mL. The 25-OH D results were compared with values obtained for reference materials (DEQAS). In addition, plasma samples were analyzed with two additional Diasorin antibody assays. All comparisons with conventional methods showed excellent correlations (r(2) = 0.9738) for DEQAS samples, demonstrating the high degree of comparability of the new UHPLC-MS/MS technique to existing methods.

  20. LC-MS/MS Method for the Simultaneous Determination of Free Urinary Steroids.

    PubMed

    Allende, Fidel; Solari, Sandra; Campino, Carmen; Carvajal, Cristian A; Lagos, Carlos F; Vecchiola, Andrea; Valdivia, Carolina; Baudrand, René; Owen, Gareth I; Fardella, Carlos E

    2014-01-01

    Cortisol homeostasis is implicated in hypertension and metabolic syndrome. Two enzymes modulate cortisol availability; 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) preferentially converts inactive cortisone to cortisol, whereas 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) converts cortisol to cortisone. In contrast, 5α and 5β reductases inactivate cortisol by conversion to its tetrahydrometabolites: tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone. A subtle local increase in cortisol can be detected by measuring 24-h urine metabolites, LC-MS/MS being the reference method. The 11β-HSD2 activity is assessed based on the cortisol/cortisone ratio, and the 11β-HSD1 activity on the (tetrahydrocortisol + allo-tetrahydrocortisol)/tetrahydrocortisone ratio. To better understand hypertension and/or metabolic syndrome pathogenesis a method for simultaneous determination of cortisol, cortisone, tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone was developed and validated in an LC coupled with the new detector AB Sciex QTrap(®) 4500 tandem mass spectrometer. The steroids were extracted from 1 mL urine, using cortisol-D4 as internal standard. The quantification range was 0.1-120 ng/mL for cortisol and cortisone, and 1-120 ng/mL for tetrahydrometabolites, with >89 % recovery for all analytes. The coefficient of variation and accuracy was <10 %, and 85-105 %, respectively. Our LC-MS/MS method is accurate and reproducible in accordance with Food and Drug Administration guidelines, showing good sensitivity and recovery. This method allows the assessment of 11β-HSD2 and 11β-HSD1 activities in a single analytical run providing an innovative tool to explain etiology of misclassified essential hypertension and/or metabolic syndrome.

  1. LC-MS/MS detection of unaltered glucuronoconjugated metabolites of metandienone.

    PubMed

    Esquivel, Argitxu; Pozo, Oscar J; Garrostas, Lorena; Balcells, Georgina; Gómez, Cristina; Kotronoulas, Aristotelis; Joglar, Jesús; Ventura, Rosa

    2016-05-30

    The aim of this study was to evaluate the direct detection of glucuronoconjugated metabolites of metandienone (MTD) and their detection times. Metabolites resistant to enzymatic hydrolysis were also evaluated. Based on the common mass spectrometric behaviour of steroid glucuronides, three liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategies were applied for the detection of unpredicted and predicted metabolites: precursor ion scan (PI), neutral loss scan (NL), and theoretical selected reaction monitoring (SRM) methods. Samples from four excretion studies of MTD were analyzed for both the detection of metabolites and the establishment of their detection times. Using PI and NL methods, seven metabolites were observed in post-administration samples. SRM methods allowed for the detection of 13 glucuronide metabolites. The detection times, measured by analysis with an SRM method, were between 1 and 22 days. The metabolite detected for the longest time was 18-nor-17β-hydroxymethyl-17α-methyl-5β-androsta-1,4,13-triene-3-one-17-glucuronide. One metabolite was resistant to hydrolysis with β-glucuronidase; however it was only detected in urine up to four days after administration. The three glucuronide metabolites with the highest retrospectivity were identified by chemical synthesis or mass spectrometric data, and although they were previously reported, this is the first time that analytical data of the intact phase II metabolites are presented for some of them. The LC-MS/MS strategies applied have demonstrated to be useful for detecting glucuronoconjugated metabolites of MTD, including glucuronides resistant to enzymatic hydrolysis which cannot be detected by conventional approaches. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Analysis of free, mono- and diacetylated polyamines from human urine by LC-MS/MS.

    PubMed

    Häkkinen, Merja R; Roine, Antti; Auriola, Seppo; Tuokko, Antti; Veskimäe, Erik; Keinänen, Tuomo A; Lehtimäki, Terho; Oksala, Niku; Vepsäläinen, Jouko

    2013-12-15

    Polyamines are promising biochemical markers of cancer and many other pathophysiological conditions, and thus their concentrations in biological fluids are a matter of interest. However, since the concentrations of these compounds are low, their quantitation is typically based on methods requiring laborious sample preparation. Here we developed and validated an LC-MS/MS method to analyze simultaneously free (DAP, PUT, CAD, SPD, SPM) monoacetylated (AcPUT, AcCAD, N(1)AcSPD, N(8)AcSPD, N(1)AcSPM) and diacetylated (DiAcPUT, DiAcCAD, DiAcSPD, DiAcSPM) polyamines from human urine without the need for derivatization. Deuterium labeled polyamines were the internal standards for each analyte. Diluted urine samples spiked with internal standards were filtered through a strong anion exchange resin prior to LC-MS/MS analysis. The chromatographic separation of 14 polyamines was achieved in 12min on C18 column with 0.1% HFBA (v/v) as the ion-pairing agent and a water-acetonitrile gradient. Ionization was performed with positive electrospray ionization (ESI) and detection was with a triple quadrupole mass spectrometer with selected reaction monitoring. Calibration curves ranged from up to 5 to 10,000nM. The accuracy and precision of the method were determined using urine based quality control samples, and matrix effects were examined by using standard addition methods. This novel method is suitable for elucidating differences in urinary polyamine excretion in cancer patients and healthy humans.

  3. Highly sensitive simultaneous quantification of estrogenic tamoxifen metabolites and steroid hormones by LC-MS/MS.

    PubMed

    Johänning, Janina; Heinkele, Georg; Precht, Jana C; Brauch, Hiltrud; Eichelbaum, Michel; Schwab, Matthias; Schroth, Werner; Mürdter, Thomas E

    2015-09-01

    Tamoxifen is a mainstay in the treatment of estrogen receptor-positive breast cancer and is metabolized to more than 30 different compounds. Little is known about in vivo concentrations of estrogenic metabolites E-metabolite E, Z-metabolite E, and bisphenol and their relevance for tamoxifen efficacy. Therefore, we developed a highly sensitive HPLC-ESI-MS/MS quantification method for tamoxifen metabolites bisphenol, E-metabolite E, and Z-metabolite E as well as for the sex steroid hormones estradiol, estrone, testosterone, androstenedione, and progesterone. Plasma samples were subjected to protein precipitation followed by solid phase extraction. Upon derivatization with 3-[(N-succinimide-1-yl)oxycarbonyl]-1-methylpyridinium iodide, all analytes were separated on a sub-2-μm column with a gradient of acetonitrile in water with 0.1 % of formic acid. Analytes were detected on a triple-quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction monitoring mode. Our method demonstrated high sensitivity, accuracy, and precision. The lower limits of quantification were 12, 8, and 25 pM for bisphenol, E-metabolite E, and Z-metabolite E, respectively, and 4 pM for estradiol and estrogen, 50 pM for testosterone and androstenedione, and 25 pM for progesterone. The method was applied to plasma samples of postmenopausal patients taken at baseline and under tamoxifen therapy. Graphical Abstract Sample preparation and derivatization for highly sensitive quantification of estrogenic tamoxifen metabolites and steroid hormones by HPLC-MS/MS.

  4. Methylmalonic acid quantification in low serum volumes by UPLC-MS/MS.

    PubMed

    Pedersen, Theresa L; Keyes, William R; Shahab-Ferdows, Setareh; Allen, Lindsay H; Newman, John W

    2011-06-01

    Methylmalonic acid (MMA) is a metabolic intermediate transformed to succinic acid (SA) by a vitamin B(12)-dependent catalytic step, and is broadly used as a clinical biomarker of functional vitamin B12 status. However, reported methods use between 100 and 1000 μL of serum or plasma making them sub-optimal for sample-limited studies, including those with neonates and infants. LC-MS/MS based protocols to measure MMA as n-butyl esters in the presence of tri-deuterated MMA (MMA-d(3)) were modified for use with 25 μL of human serum by scaling down sample processing volumes and analysis by UPLC-MS/MS. Plasma-based calibration solutions were found to be unnecessary, and chromatographic resolution and peak shape of SA and MMA was optimized in <4 min with isocratic 53:47 methanol/1.67 mM (pH 6.5) ammonium formate. Additionally, 1-cyclohexyl-urido-3-dodecanoic acid (CUDA) was included as internal standard allowing direct assessment of MMA recovery. Sample concentrations in the low normal range produced a signal:noise of >100:1. MMA intra- and inter-assay variability was under 10%. MMA-d(3) surrogate recovery averaged 93±14%. MMA stability exceeded three years in frozen samples and was unaffected by up to five freeze/thaw cycles. In conclusion, we report that methylmalonic acid can be measured with 25 μL of serum using water based standards. The assay signal:noise per concentration indicates that the method could perform as implemented with as little as 5 μL of serum. The reported method is applicable for studies of functional B12 status in sample limited experiments including investigations of nutritional status in neonates and in studies where low normal MMA levels are expected.

  5. Analysis and Exposure Assessment of Perchlorate in Korean Dairy Products with LC-MS/MS

    PubMed Central

    Oh, Sung-Hee; Lee, Ji-Woo; Mandy, Pawlas

    2011-01-01

    Objectives Perchlorate is an emerging contaminant that is found everywhere, including various foods. Perchlorate is known to disturb the production of thyroid hormones and leads to mental disorders in fetuses and infants, as well as metabolic problems in adults. In this study, we attempted to establish an LC-MS/MS method for measuring perchlorate in dairy products and used this developed method to investigate perchlorate levels in Korean milk and yogurt samples. Methods The developed method of perchlorate analysis requires a shaker and 1% acetic acid/acetonitrile as the extracting solvent. Briefly, the samples were extracted and then centrifuged (4000 rpm, 1hour), and the supernatant was then passed through a Envi™ Carb SPE cartridge that had been prewashed sequentially with 6 mL of acetonitrile and 6 mL of 1% acetic acid in water. The final volume of the sample extract was adjusted to 40 mL with reagent water and the final sample was filtered through a 0.20-µm pore size PTFE (Polytetrafluoroethylene) syringe filter prior to LC-MS/MS. Results The average levels of perchlorate in milk and yogurt samples were 5.63 ± 3.49 µg/L and 3.65 ± 2.42 µg/L, respectively. The perchlorate levels observed in milk samples in this study were similar to those reported from China, Japan, and the United States. Conclusions The exposure of Koreans to perchlorate through the consumption of dairy products was calculated based on the results of this study. For all age groups, the calculated exposure to perchlorate was below the reference of dose (0.7 µg/kg-day) proposed by the National Academy of Science, USA, but the perchlorate exposure of children was higher than that of adults. Therefore, further investigation of perchlorate in other food samples is needed to enable a more exact assessment of exposure of children to perchlorate. PMID:22125772

  6. STS-47 MS Davis and MS/PLC Lee inspect SLJ Rack 5 during KSC training

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-47 Endeavour, Orbiter Vehicle (OV) 105, Mission Specialist N. Jan Davis and MS and Payload Commander (PLC) Mark C. Lee, wearing clean suits, check latches on the Spacelab Japan (SLJ) Rack 5 Adult Frog Compartment during an inspection of the SLJ module which is currently undergoing preflight processing in a high bay of the Kennedy Space Center's (KSC's) Orbiter Processing Facility (OPF). View provided by KSC with alternate KSC number KSC-92PC-1643.

  7. STS-47 MS Davis and MS/PLC Lee examine SLJ Rack 10 during KSC inspection

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-47 Endeavour, Orbiter Vehicle (OV) 105, Mission Specialist N. Jan Davis and MS and Payload Commander (PLC) Mark C. Lee, wearing clean suits, examine NASDA Material Sciences control panel on Spacelab Japan (SLJ) Rack 10 during an inspection of the SLJ module. The module is currently undergoing preflight processing in a high bay of the Kennedy Space Center's (KSC's) Orbiter Processing Facility (OPF). View provided by KSC with alternate KSC number KSC-92PC-1644.

  8. Therapeutic monitoring of amphotericin B in Saudi ICU patients using UPLC MS/MS assay.

    PubMed

    Al-Quadeib, Bushra T; Radwan, Mahasen A; Siller, Lidija; Mutch, Elaine; Horrocks, Ben; Wright, Matthew; Alshaer, Abdulaziz

    2014-12-01

    Amphotericin B (AmB) is the first-line agent for the treatment of life-threatening invasive fungal infections. The aim of this study was to monitor AmB in critically ill Saudi patients in ICU after i.v. administration of 0.68 ± 0.1 mg/kg/day Fungizone®. A selective, sensitive and precise UPLC MS/MS method was developed to measure AmB concentrations in these patients. Seven ICU patients with creatinine clearance (ClCr) >40 mL/min were included. AmB levels were analyzed using a Waters Aquity UPLC MS/MS system, a BEH Shield RP18 column and detection via electrospray ionization source with positive ionization mode. The precision and accuracy of the developed UPLC method in the concentration range of 200-4000 ng/mL show no significant difference among inter- and-intra-day analysis (p > 0.05). Linearity was observed over the investigated range with correlation coefficient, r > 0.995 (n = 6/day). The pharmacokinetics of AmB in these patients, at steady state, showed a high terminal half-life of 124.6 ± 73.4 h, with a highest concentration of 513.9 ± 281.1 ng/mL, a lowest concentration 316.4 ± 129.0 ng/mL and a mean clearance 91.1 ± 39.2 mL/h/kg. The pharmacokinetics of AmB in critically ill Saudi patients in ICU was studied using a fully validated assay. A weak correlation (r = -0.22) of AmB Cl with ClCr was obtained, which suggests the need for further investigation in a larger population.

  9. LC-MS/MS Analysis Unravels Deep Oxidation of Manganese Superoxide Dismutase in Kidney Cancer

    PubMed Central

    Zhao, Zuohui; Azadzoi, Kazem M.; Choi, Han-Pil; Jing, Ruirui; Lu, Xin; Li, Cuiling; Wang, Fengqin; Lu, Jiaju; Yang, Jing-Hua

    2017-01-01

    Manganese superoxide dismutase (MNSOD) is one of the major scavengers of reactive oxygen species (ROS) in mitochondria with pivotal regulatory role in ischemic disorders, inflammation and cancer. Here we report oxidative modification of MNSOD in human renal cell carcinoma (RCC) by the shotgun method using data-dependent liquid chromatography tandem mass spectrometry (LC-MS/MS). While 5816 and 5571 proteins were identified in cancer and adjacent tissues, respectively, 208 proteins were found to be up- or down-regulated (p < 0.05). Ontological category, interaction network and Western blotting suggested a close correlation between RCC-mediated proteins and oxidoreductases such as MNSOD. Markedly, oxidative modifications of MNSOD were identified at histidine (H54 and H55), tyrosine (Y58), tryptophan (W147, W149, W205 and W210) and asparagine (N206 and N209) residues additional to methionine. These oxidative insults were located at three hotspots near the hydrophobic pocket of the manganese binding site, of which the oxidation of Y58, W147 and W149 was up-regulated around three folds and the oxidation of H54 and H55 was detected in the cancer tissues only (p < 0.05). When normalized to MNSOD expression levels, relative MNSOD enzymatic activity was decreased in cancer tissues, suggesting impairment of MNSOD enzymatic activity in kidney cancer due to modifications. Thus, LC-MS/MS analysis revealed multiple oxidative modifications of MNSOD at different amino acid residues that might mediate the regulation of the superoxide radicals, mitochondrial ROS scavenging and MNSOD activity in kidney cancer. PMID:28165386

  10. LC-MS/MS screening method for designer amphetamines, tryptamines, and piperazines in serum.

    PubMed

    Wohlfarth, Ariane; Weinmann, Wolfgang; Dresen, Sebastian

    2010-04-01

    Since the late 1990s and early 2000s, derivatives of well-known designer drugs as well as new psychoactive compounds have been sold on the illicit drug market and have led to intoxications and fatalities. The LC-MS/MS screening method presented covers 31 new designer drugs as well as cathinone, methcathinone, phencyclidine, and ketamine which were included to complete the screening spectrum. All but the last two are modified molecular structures of amphetamine, tryptamine, or piperazine. Among the amphetamine derivatives are cathinone, methcathinone, 3,4-DMA, 2,5-DMA, DOB, DOET, DOM, ethylamphetamine, MDDMA, 4-MTA, PMA, PMMA, 3,4,5-TMA, TMA-6 and members of the 2C group: 2C-B, 2C-D, 2C-H, 2C-I, 2C-P, 2C-T-2, 2C-T-4, and 2C-T-7. AMT, DPT, DiPT, MiPT, DMT, and 5MeO-DMT are contained in the tryptamine group, BZP, MDBP, TFMPP, mCPP, and MeOPP in the piperazine group. Using an Applied Biosystems LC-MS/MS API 365 TurboIonSpray it is possible to identify all 35 substances. After addition of internal standards and mixed-mode solid-phase extraction the analytes are separated using a Synergi Polar RP column and gradient elution with 1 mM ammonium formate and methanol/0.1% formic acid as mobile phases A and B. Data acquisition is performed in MRM mode with positive electro spray ionization. The assay is selective for all tested substances. Limits of detection were determined by analyzing S/N-ratios and are between 1.0 and 5.0 ng/mL. Matrix effects lie between 65% and 118%, extraction efficiencies range from 72% to 90%.

  11. Determination of cannabinoids in whole blood by UPLC-MS-MS.

    PubMed

    Jamey, Carole; Szwarc, Esther; Tracqui, Antoine; Ludes, Bertrand

    2008-06-01

    An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method was developed and validated for the simultaneous determination of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THC-COOH) in whole blood. Samples were prepared by protein precipitation followed by solid-phase extraction. Data were acquired using positive electrospray ionization and multiple reaction monitoring. Two transitions were selected for THC (m/z 315.0 > 193.0 and m/z 315.0 > 122.7) and THC-COOH (m/z 345.0 > 299.0 and m/z 345.0 > 327.0), and one transition was chosen for 11-OH-THC (m/z 331.0 > 313.0). Deuterated analogues of each analyte were used as internal standards for quantification. Run time was 10 min. Limits of quantification (LOQ) were 0.05 ng/mL for THC, 0.1 ng/mL for 11-OH-THC, and 0.2 ng/mL for THC-COOH. Linearity was established from LOQ to 50 ng/mL for each substance (r(2) always > 0.999). Accuracy ranged from 96 to 106%, and imprecision was less than 10% for all analytes. The UPLC-MS-MS method was found to be sensitive, specific, and rapid because it requires no derivatization step. It can be an alternative to gas chromatography-mass spectrometry for the determination of cannabinoids in whole blood.

  12. QC Metrics from CPTAC Raw LC-MS/MS Data Interpreted through Multivariate Statistics

    PubMed Central

    2015-01-01

    Shotgun proteomics experiments integrate a complex sequence of processes, any of which can introduce variability. Quality metrics computed from LC-MS/MS data have relied upon identifying MS/MS scans, but a new mode for the QuaMeter software produces metrics that are independent of identifications. Rather than evaluating each metric independently, we have created a robust multivariate statistical toolkit that accommodates the correlation structure of these metrics and allows for hierarchical relationships among data sets. The framework enables visualization and structural assessment of variability. Study 1 for the Clinical Proteomics Technology Assessment for Cancer (CPTAC), which analyzed three replicates of two common samples at each of two time points among 23 mass spectrometers in nine laboratories, provided the data to demonstrate this framework, and CPTAC Study 5 provided data from complex lysates under Standard Operating Procedures (SOPs) to complement these findings. Identification-independent quality metrics enabled the differentiation of sites and run-times through robust principal components analysis and subsequent factor analysis. Dissimilarity metrics revealed outliers in performance, and a nested ANOVA model revealed the extent to which all metrics or individual metrics were impacted by mass spectrometer and run time. Study 5 data revealed that even when SOPs have been applied, instrument-dependent variability remains prominent, although it may be reduced, while within-site variability is reduced significantly. Finally, identification-independent quality metrics were shown to be predictive of identification sensitivity in these data sets. QuaMeter and the associated multivariate framework are available from http://fenchurch.mc.vanderbilt.edu and http://homepages.uc.edu/~wang2x7/, respectively. PMID:24494671

  13. Liquid- and gas-phase nitration of bovine serum albumin studied by LC-MS and LC-MS/MS using monolithic columns.

    PubMed

    Walcher, Wolfgang; Franze, Thomas; Weller, Michael G; Pöschl, Ulrich; Huber, Christian G

    2003-01-01

    Post-translational nitration of proteins was analyzed by capillary reversed-phase high-performance liquid chromatography (RP-HPLC) on-line interfaced to electrospray ionization mass spectrometry (ESI--MS) or tandem mass spectrometry (ESI--MS/MS). Both methods were compared using a tryptic digest of bovine serum albumin (BSA) and yielded sequence coverages of 95% and 33% with RP-HPLC--ESI--MS and RP-HPLC--ESI--MS/MS, respectively. At least 95% of the tyrosines were covered by the former method, whereas the latter method only detected less than 50% of the tyrosine-containing peptides. Upon liquid-phase nitration of BSA in aqueous solution using an excess of tetranitromethane, at least 16 of the 20 tyrosine residues were found to be nitrated. After exposure of solid BSA samples to gaseous nitrogen dioxide and ozone at atmospherically relevant concentration levels, only 3 nitrated peptides were detected. By use of such a model system, RP-HPLC--ESI--MS proved to be a rapid and highly efficient method for the comprehensive and quantitative detection of protein nitration.

  14. 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).

  15. Quantification of flavonol glycosides in Camellia sinensis by MRM mode of UPLC-QQQ-MS/MS.

    PubMed

    Wu, Yahui; Jiang, Xiaolan; Zhang, Shuxiang; Dai, Xinlong; Liu, Yajun; Tan, Huarong; Gao, Liping; Xia, Tao

    2016-04-01

    Phenolic compounds are major components of tea flavour, in which catechins and flavonol glycosides play important roles in the astringent taste of tea infusion. However, the flavonol glycosides are difficult to quantify because of the large variety, as well as the inefficient seperation on chromatography. In this paper, a total of 15 flavonol glycosides in the tea plant (Camellia sinensis) were identified by the high performance liquid chromatography (HPLC) coupled to a time-of-flight mass spectrometer (TOF-MS), and a quantitative method was established based on multiple reaction monitoring (MRM) mode of ultra-high performance liquid chromatography (UPLC) coupled to a triple quadrupole mass spectrometer (QQQ-MS/MS). It provided the limit of detection and quantification to the order of picogram, which was more sensitive than the HPLC detection of the order of nanogram. The relative standard deviations of the intra- and inter-day variations in retention time and signal intensity (peak area) of six analytes were less than 0.26% and 4%, respectively. The flavonol glycosides of four tea cultivars were relatively quantified using the signal intensity (peak area) of product ion, in which six flavonol glycosides were quantified by the authentic standards. The results showed that the flavonol mono-, di- and tri-glycoside mostly accumulated in young leaves of the four tea cultivars. Notably, the myricetin 3-O-galactoside was the major component among the six flavonol glycosides detected.

  16. DESI-MS/MS of Chemical Warfare Agents and Related Compounds

    NASA Astrophysics Data System (ADS)

    D'Agostino, Paul A.

    Solid phase microextraction (SPME) fibers were used to headspace ­sample chemical warfare agents and their hydrolysis products from glass vials and glass vials containing spiked media, including Dacron swabs, office carpet, paper and fabric. The interface of the Z-spray source was modified to permit safe introduction of the SPME fibers for desorption electrospray ionization mass spectrometric (DESI-MS) analysis. A "dip and shoot" method was also developed for the rapid sampling and DESI-MS analysis of chemical warfare agents and their hydrolysis products in liquid samples. Sampling was performed by simply dipping fused silica, stainless steel or SPME tips into the organic or aqueous samples. Replicate analyses were completed within several minutes under ambient conditions with no sample pre-treatment, resulting in a significant increase in sample throughput. The developed sample handling and analysis method was applied to the determination of chemical warfare agent content in samples containing unknown chemical and/or biological warfare agents. Ottawa sand was spiked with sulfur mustard, extracted with water and autoclaved to ensure sterility. Sulfur mustard was completely hydrolysed during the extraction/autoclave step and thiodiglycol was identified by DESI-MS, with analyses generally being completed within 1 min using the "dip and shoot" method.

  17. Identification and quantitation of new glutamic acid derivatives in soy sauce by UPLC/MS/MS.

    PubMed

    Frerot, Eric; Chen, Ting

    2013-10-01

    Glutamic acid is an abundant amino acid that lends a characteristic umami taste to foods. In fermented foods, glutamic acid can be found as a free amino acid formed by proteolysis or as a non-proteolytic derivative formed by microorganisms. The aim of the present study was to identify different structures of glutamic acid derivatives in a typical fermented protein-based food product, soy sauce. An acidic fraction was prepared with anion-exchange solid-phase extraction (SPE) and analyzed by UPLC/MS/MS and UPLC/TOF-MS. α-Glutamyl, γ-glutamyl, and pyroglutamyl dipeptides, as well as lactoyl amino acids, were identified in the acidic fraction of soy sauce. They were chemically synthesized for confirmation of their occurrence and quantified in the selected reaction monitoring (SRM) mode. Pyroglutamyl dipeptides accounted for 770 mg/kg of soy sauce, followed by lactoyl amino acids (135 mg/kg) and γ-glutamyl dipeptides (70 mg/kg). In addition, N-succinoylglutamic acid was identified for the first time in food as a minor compound in soy sauce (5 mg/kg).

  18. Simultaneous determination of 10 nucleosides and nucleobases in Antrodia camphorata using QTRAP LC-MS/MS.

    PubMed

    Chen, Fei; Zhang, Fengsu; Yang, Nianyun; Liu, Xunhong

    2014-09-01

    A liquid chromatography-triple-quadrupole linear ion trap mass spectrometry (LC-QTrap-MS) analysis has been developed for the identification and quantification of 10 nucleosides and nucleobases in extracts of Antrodia camphorata. The method was successfully used to qualitatively identify for six nucleosides namely, cytidine, uridine, inosine, guanosine, thymidine, adenosine and four nucleobases namely, uracil, guanine, xanthine, adenine in A. camphorata. Under optimized chromatographic conditions, good separation for 10 target compounds were obtained on an Agilent HC-C18(2) column (4.6 × 250 mm, 5 μm) eluted by a mobile phase of 5 mM ammonium acetate solution-methanol at a flow rate of 0.5 mL/min. Data acquisition was carried out in multiple reaction monitoring transition mode. Additional identification and confirmation of target compounds were performed using the enhanced product ion modus of the linear ion trap. It was the first report about simultaneous analysis of nucleosides and nucleobases in A. camphorata using this method. These results demonstrated that the QTRAP LC-MS/MS was a useful tool for quality evaluation of some medicinal plant products by using nucleosides and nucleobases as chemical markers. This method might also be utilized for the investigation of edible plant materials and agricultural products containing nucleosides and nucleobases.

  19. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies.

    PubMed

    Abobo, Cyril V; Wu, Lei; John, Jyothy; Joseph, Mathew K; Bates, Theodore R; Liang, Dong

    2010-11-15

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C₁₈ column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1-100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model.

  20. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies

    PubMed Central

    Abobo, Cyril; Wu, Lei; John, Jyothy; Joseph, Mathew K.; Bates, Theodore R.; Liang, Dong

    2010-01-01

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C18 column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1 ng/mL to 100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model. PMID:20965798

  1. 58. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER'S BRIDGE, 1884, Ms. 14, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER'S BRIDGE, 1884, Ms. 14, E 6.5 mi. to McLeod, 4.5 miles S on McLeod-Shuqualak road. Mahorner's bridge (1884). Lower panel point, west span. View is at right-angles to the bridge and from below deck level. show pin connection, floor beams, and stringers. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  2. The Navy’s M&S Standards Development Activities

    DTIC Science & Technology

    2010-01-01

    identify supporting protocols, techniques and processes. The purpose of this paper is to provide an overview of the Navy’s M&S standards development ...process and to identify new opportunities to develop and promote M&S Standards across the DoD and industry M&S communities. We will specifically...on the premise that no simulation can satisfy all uses and users. An individual simulation, or set of simulations, developed for one purpose can be

  3. A novel study of screening and confirmation of modafinil, adrafinil and their metabolite modafinilic acid under EI-GC-MS and ESI-LC-MS-MS ionization

    PubMed Central

    Dubey, S.; Ahi, S.; Reddy, I. M.; Kaur, T.; Beotra, A.; Jain, S.

    2009-01-01

    Objective: Adrafinil and modafinil have received wide publicity and have become controversial in the sporting world when several athletes were discovered allegedly using these drugs as doping agents. By acknowledging the facts, the World Anti-Doping Agency (WADA) banned these drugs in sports since 2004. The present study explores the possibility of differentiating adrafinil and modafinil and their major metabolites under electron impact ionization in gas chromatograph–mass spectrometer (GC-MSD) and electrospray ionization in liquid chromatograph–mass spectrometer (LC-MS/MS) by studying the fragmentation pattern of these drugs. Materials and Methods: Adrafinil, modafinil and their major metabolite, modafinilic acid were analyzed on EI-GC-MSD and ESI-LC-MS/MS using various individual parameters on both the instruments. The analytical technique and equipment used in the analysis were an Agilent 6890N GC with 5973 mass selective detector for the GC-MSD analysis and an Agilent 1100 HPLC with API-3200 Triple quadrupole mass spectrometer for the LC-MS/MS analysis. Validation of both methods was performed using six replicates at different concentrations. Result and Discussion: The results show that adrafinil, modafinil and their major metabolite modafinilic acid could be detected as a single artifact without differentiation under EI-GC-MSD analysis. However, all drugs could be detected and differentiated under ESI-LCMS/MS analysis without any artifaction. The GC-MSD analysis gives a single artifact for both the drugs without differentiation and thus can be used as a marker for screening purposes. Further, the Multiple Reaction Monitoring (MRM) method developed under LC-MS/MS is fit for the purpose for confirmation of suspicious samples in routine sports testing and in forensic and clinical analysis. PMID:20407560

  4. Diagnosing Depression in MS in the Face of Overlapping Symptoms.

    PubMed

    Patten, Sb

    2010-01-01

    Depression is an important problem in multiple sclerosis (MS), but the diagnosis is challenging since symptoms of depression overlap with those of MS. In the past, the main strategy has been to remove physical symptoms from scales assessing depressive symptoms in MS, but these attempts have not been successful. Depression and overlapping MS symptoms may actually share pathophysiological mechanisms, so the strategy of attempting to exclude such symptoms may be fundamentally flawed. Current diagnostic criteria provide a pragmatic solution, but it may be possible to develop improved definitions.

  5. A new type of GC-MS with advanced capabilities

    NASA Astrophysics Data System (ADS)

    Fialkov, Alexander B.; Steiner, Urs; Jones, Larry; Amirav, Aviv

    2006-03-01

    We have combined the benefits of supersonic molecular beam interface and its related fly-through electron ionization (EI) ion source with the advanced features of the Varian 1200L gas chromatography-mass spectrometry (GC-MS) and mass spectrometry-mass spectrometry (MS-MS), resulting in a new and powerful GC-MS platform with record setting performance. Electron ionization of vibrationally cold molecules in the supersonic molecular beams (SMB) (cold EI) provided mass spectra with enhanced molecular ion, yet with good library search results and superior identification probabilities. We found that high GC column flow rates lower the elution temperature for any given compounds. This allows much larger molecules to elute at the maximum temperature of standard columns. We analyzed a mixture of heavy linear chain hydrocarbons all the way to C84H170 with a molecular weight of 1179.3 amu, using a 4 m 0.25 mm i.d. column and 32 ml/min He flow rate. Furthermore, we obtained a dominant molecular ion to all these compounds. The lower elution temperatures also greatly enhance the ability to analyze very thermally labile compounds such as carbamate pesticides. The experimental 1200 system is capable of triple quadrupole based MS-MS. We found that MS-MS on the molecular ion is much more effective than on fragment ions, and thus, the enhancement of the molecular ion directly improves the MS-MS sensitivity. Fast GC-MS analysis was also explored, based on very high column flow rate for fast splitless injections without affecting the sensitivity, and on the high system selectivity due to the combination of enhanced molecular ion and MS-MS. We demonstrate a few seconds long GC-MS-MS analysis of diazinon, spiked at 10 ng/g in a mixed fruit and vegetable extract. The feature of enhanced molecular ion provides significant enhancement in the detection sensitivity via SIM and RSIM on the molecular ion. While octafluoronaphthalene (OFN) detection limit of below 1 fg in SIM mode is shown, the

  6. Ethyl Esterification for MALDI-MS Analysis of Protein Glycosylation.

    PubMed

    Reiding, Karli R; Lonardi, Emanuela; Hipgrave Ederveen, Agnes L; Wuhrer, Manfred

    2016-01-01

    Ethyl esterification is a technique for the chemical modification of sialylated glycans, leading to enhanced stability when performing matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS), as well as allowing the efficient detection of both sialylated and non-sialylated glycans in positive ion mode. In addition, the method shows specific reaction products for α2,3- and α2,6-linked sialic acids, leading to an MS distinguishable mass difference. Here, we describe the ethyl esterification protocol for 96 glycan samples, including enzymatic N-glycan release, the aforementioned ethyl esterification, glycan enrichment, MALDI target preparation, and the MS(/MS) measurement.

  7. International Pediatric MS Study Group Global Members Symposium report.

    PubMed

    Wassmer, Evangeline; Chitnis, Tanuja; Pohl, Daniela; Amato, Maria Pia; Banwell, Brenda; Ghezzi, Angelo; Hintzen, Rogier Q; Krupp, Lauren B; Makhani, Naila; Rostásy, Kevin; Tardieu, Marc; Tenembaum, Silvia; Waldman, Amy; Waubant, Emmanuelle; Kornberg, Andrew J

    2016-08-30

    The International Pediatric Multiple Sclerosis Study Group held its inaugural educational program, "The World of Pediatric MS: A Global Update," in September 2014 to discuss advances and challenges in the diagnosis and management of pediatric multiple sclerosis (MS) and other neuroinflammatory CNS disorders. Highlights included a discussion on the revised diagnostic criteria, which enable the differentiation of MS, acute disseminated encephalomyelitis, neuromyelitis optica, and other neuroinflammatory disorders. While these criteria currently identify clinical and MRI features for a particular diagnosis, advances in biomarkers may prove to be useful in the future. An update was also provided on environmental factors associated with pediatric MS risk and possibly outcomes, notably vitamin D deficiency. However, optimal vitamin D intake and its role in altering MS course in children have yet to be established. Regarding MS outcomes, our understanding of the cognitive consequences of early-onset MS has grown. However, further work is needed to define the course of cognitive function and its long-term outcome in diverse patient samples and to develop strategies for effective cognitive rehabilitation specifically tailored to children and adolescents. Finally, treatment strategies were discussed, including a need to consider additional drug treatment options and paradigms (escalation vs induction), although treatment should be tailored to the individual child. Of critical importance, clinical trials of newer MS agents in children are required. Although our understanding of childhood MS has improved, further research is needed to have a positive impact for children and their families.

  8. Preprocessing and Analysis of LC-MS-Based Proteomic Data

    PubMed Central

    Tsai, Tsung-Heng; Wang, Minkun; Ressom, Habtom W.

    2016-01-01

    Liquid chromatography coupled with mass spectrometry (LC-MS) has been widely used for profiling protein expression levels. This chapter is focused on LC-MS data preprocessing, which is a crucial step in the analysis of LC-MS based proteomics. We provide a high-level overview, highlight associated challenges, and present a step-by-step example for analysis of data from LC-MS based untargeted proteomic study. Furthermore, key procedures and relevant issues with the subsequent analysis by multiple reaction monitoring (MRM) are discussed. PMID:26519169

  9. EMS & the DEA.

    PubMed

    Beeson, Jeff; Ayres, Chris

    2010-01-01

    It's clear that EMS medical directors and management staff must be vigilant in their oversight of implementation, administration and monitoring of controlled substances within their agencies to best serve the public and avoid running afoul of investigation and incurring significant penalties. Those potentially affected by the need for individual registrations of both emergency vehicles and central inventory systems should carefully monitor upcoming developments in the interpretation od DEA regulations.

  10. Quantitative analysis of lipids: a higher-throughput LC–MS/MS-based method and its comparison to ELISA

    PubMed Central

    Gandhi, Adarsh S; Budac, David; Khayrullina, Tanzilya; Staal, Roland; Chandrasena, Gamini

    2017-01-01

    Aim: Lipids such as prostaglandins, leukotrienes and thromboxanes are released as a result of an inflammatory episode in pain (central and peripheral). Methodology & results: To measure these lipids as potential mechanistic biomarkers in neuropathic pain models, we developed a higher-throughput LC–MS/MS-based method with simultaneous detection of PGE2, PGD2, PGF2α, LTB4, TXB2 and 2-arachidonoyl glycerol in brain and spinal cord tissues. We also demonstrate that the LC–MS/MS method was more sensitive and specific in differentiating PGE2 levels in CNS tissues compared with ELISA. Conclusion: The ability to modify the LC–MS/MS method to accommodate numerous other lipids in one analysis, demonstrates that the presented method offers a cost–effective and more sensitive alternative to ELISA method useful in drug discovery settings. PMID:28344822

  11. LC-ESI-MS/MS identification of polar lipids of two thermophilic Anoxybacillus bacteria containing a unique lipid pattern.

    PubMed

    Rezanka, Tomáš; Kambourova, Margarita; Derekova, Anna; Kolouchová, Irena; Sigler, Karel

    2012-07-01

    Phospholipids and glycolipids from two recently described species belonging to the thermophilic genus Anoxybacillus were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC/ESI-MS/MS). Analysis of total lipids from the facultatively anaerobic A. bogrovensis on a HILIC (Hydrophilic Interaction LIquid Chromatography) column succeeded in separating diacyl- and plasmalogen phospholipids. The LC/ESI-MS/MS analysis of the strict aerobe A. rupiensis revealed the presence of different unique polar lipids, predominantly alanyl-, lysyl-, and glucosyl-phosphatidylglycerols and cardiolipins. Each of the classes of polar lipids was then analyzed by means of the ESI-MS/MS and more than 140 molecular species of six lipid classes from A. bogrovensis and nearly 200 molecular species of nine classes of polar lipids from A. rupiensis were identified. Five classes of unidentified polar lipids were detected in both strains. Plasmalogens were thus determined for the first time in a facultatively anaerobic bacterium, i.e. A. bogrovensis.

  12. Evaluation of GC-ion trap-MS/MS methodology for monitoring PCDD/Fs in infant formulas.

    PubMed

    Lorán, Susana; Bayarri, Susana; Conchello, Pilar; Herrera, Antonio

    2007-03-01

    The application of high resolution gas chromatography in combination with low resolution mass spectrometry with electron ionization and MS/MS detection (HRGC-MS/MS) is tested for its use in the analysis of PCDD/Fs in infant formulas. Development of the analytical method was based upon EPA directrices and international recommendations. Calibration linearity was tested and average relative response for any native and labelled compound over the five-point calibration range below 14% was found. The precision and accuracy of the proposed analytical procedure are also presented. Results obtained are in agreement with EPA criteria. The method is applied to the analysis of a number of initial and follow-on milk based infant formulas. In general, HRGC-MS/MS constitutes an interesting method for the analysis of dioxins in such matrices.

  13. Quantification of Dehydroepiandrosterone, 11-Deoxycortisol, 17-Hydroxyprogesterone, and Testosterone by Liquid Chromatography-Tandem Mass Spectrometry (LC/MS/MS).

    PubMed

    Munar, Ada; Frazee, Clint; Garg, Uttam

    2016-01-01

    Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders due to enzymatic defects in the biosynthetic pathway of cortisol and/or aldosterone. The analysis of cortisol, 17-hydroxyprogesterone (OHPG), dehydroepiandrosterone (DHEA), 11-deoxycortisol, and testosterone is generally performed in the diagnosis and/or follow-up of CAH. Cortisol is generally analyzed by immunoassays whereas other hormones are preferably assayed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). A multiple reaction monitoring, positive mode atmospheric pressure chemical ionization, LC/MS/MS method is described for the simultaneous quantification of 17-hydroxyprogesterone, DHEA, 11-deoxycortisol, and testosterone. Stable-isotope labeled internal standards are added to serum samples and steroids are extracted by liquid-liquid extraction using methyl tert-butyl ether. The extract is evaporated under stream of nitrogen and the residue is reconstituted in methanol and analyzed by LC/MS/MS.

  14. MS/MS-Assisted Design of Sequence-Controlled Synthetic Polymers for Improved Reading of Encoded Information

    NASA Astrophysics Data System (ADS)

    Charles, Laurence; Cavallo, Gianni; Monnier, Valérie; Oswald, Laurence; Szweda, Roza; Lutz, Jean-François

    2016-12-01

    In order to improve their MS/MS sequencing, structure of sequence-controlled synthetic polymers can be optimized based on considerations regarding their fragmentation behavior in collision-induced dissociation conditions, as demonstrated here for two digitally encoded polymer families. In poly(triazole amide)s, the main dissociation route proceeded via cleavage of the amide bond in each monomer, hence allowing the chains to be safely sequenced. However, a competitive cleavage of an ether bond in a tri(ethylene glycol) spacer placed between each coding moiety complicated MS/MS spectra while not bringing new structural information. Changing the tri(ethylene glycol) spacer to an alkyl group of the same size allowed this unwanted fragmentation pathway to be avoided, hence greatly simplifying the MS/MS reading step for such undecyl-based poly(triazole amide)s. In poly(alkoxyamine phosphodiester)s, a single dissociation pathway was achieved with repeating units containing an alkoxyamine linkage, which, by very low dissociation energy, made any other chemical bonds MS/MS-silent. Structure of these polymers was further tailored to enhance the stability of those precursor ions with a negatively charged phosphate group per monomer in order to improve their MS/MS readability. Increasing the size of both the alkyl coding moiety and the nitroxide spacer allowed sufficient distance between phosphate groups for all of them to be deprotonated simultaneously. Because the charge state of product ions increased with their polymerization degree, MS/MS spectra typically exhibited groups of fragments at one or the other side of the precursor ion depending on the original α or ω end-group they contain, allowing sequence reconstruction in a straightforward manner.

  15. Time correlation between mononucleosis and initial symptoms of MS

    PubMed Central

    Endriz, John; Ho, Peggy P.

    2017-01-01

    Objective: To determine the average age of MS onset vs the age at which Epstein-Barr infection has previously occurred and stratify this analysis by sex and the blood level of Epstein-Barr nuclear antigen 1 (EBNA1) antibody. Methods: Using infectious mononucleosis (IM) as a temporal marker in data from the Swedish epidemiologic investigation of MS, 259 adult IM/MS cases were identified and then augmented to account for “missing” childhood data so that the average age of MS onset could be determined for cases binned by age of IM (as stratified by sex and EBNA1 titer level). Results: Mean age of IM vs mean age of MS reveals a positive time correlation for all IM ages (from ∼5 to ∼30 years), with IM-to-MS delay decreasing with increased age. When bifurcated by sex or EBNA1 blood titer levels, males and high-titer subpopulations show even stronger positive time correlation, while females and low-titer populations show negative time correlation in early childhood (long IM/MS delay). The correlation becomes positive in females beyond puberty. Conclusions: IM/MS time correlation implies causality if IM is time random. Alternative confounding models seem implausible, in light of constraints imposed by time-invariant delay observed here. Childhood infection with Epstein-Barr virus (EBV) in females and/or those genetically prone to low EBNA1 blood titers will develop MS slowly. Males and/or high EBNA1-prone develop MS more rapidly following IM infection at all ages. For all, postpubescent EBV infection is critical for the initiation and rapid development of MS. PMID:28271078

  16. Biodegradation of the (aliphatic + aromatic) fraction of Oural crude oil. Biomarker identification using GC/MS SIM and GC/MS/MS.

    PubMed

    Jacquot, F; Doumenq, P; Guiliano, M; Munoz, D; Guichard, J R; Mille, G

    1996-03-01

    A simplified fraction of the Oural crude oil (aliphatic and aromatic hydrocarbons) was incubated in the presence of an hydrocarbonoclastic bacterial community isolated from a marine sediment highly contaminated by petroleum residue. The biodegradation has been carried out under aerobic conditions for 5 weeks and followed by FTIR, UV synchronous luminescence and GC/FID. Disappearance of the n-alkanes (2nd week), an important attack of the isoprenoïd compounds (5th week) and preferential alteration of monomethylated polyaromatics were observed. Concerning the biomarkers, the bicyclic alkanes and pentacyclic terpanes have been comparatively elucidated using GC/MS data. The identification of C(26) to C(29) steranes has required a most selective method, namely GC/MS/MS. Many molecular ratios based on GC/MS abundances were calculated, which showed good stability. Consequently, they can be used to determine the origin of a petroleum even one altered by biodegradation.

  17. Simultaneous screening of targeted and non-targeted contaminants using an LC-QTOF-MS system and automated MS/MS library searching.

    PubMed

    Herrera-Lopez, S; Hernando, M D; García-Calvo, E; Fernández-Alba, A R; Ulaszewska, M M

    2014-09-01

    Simultaneous high-resolution full-scan and tandem mass spectrometry (MS/MS) analysis using time of flight mass spectrometry brings an answer for increasing demand of retrospective and non-targeted data analysis. Such analysis combined with spectral library searching is a promising tool for targeted and untargeted screening of small molecules. Despite considerable extension of the panel of compounds of tandem mass spectral libraries, the heterogeneity of spectral data poses a major challenge against the effective usage of spectral libraries. Performance evaluation of available LC-MS/MS libraries will significantly increase credibility in the search results. The present work was aimed to evaluate fluctuation of MS/MS pattern, in the peak intensities distribution together with mass accuracy measurements, and in consequence, performance compliant with ion ratio and mass error criteria as principles in identification processes for targeted and untargeted contaminants at trace levels. Matrix effect and ultra-trace levels of concentration (from 50 ng l(-1) to 1000 ng l(-1) were evaluated as potential source of inaccuracy in the performance of spectral matching. Matrix-matched samples and real samples were screened for proof of applicability. By manual review of data and application of ion ratio and ppm error criteria, false negatives were obtained; this number diminished when in-house library was used, while with on-line MS/MS databases 100% of positive samples were found. In our experience, intensity of peaks across spectra was highly correlated to the concentration effect and matrix complexity. In turn, analysis of spectra acquired at trace concentrations and in different matrices results in better performance in providing correct and reliable identification.

  18. Proteome profile of zebrafish caudal fin based on one-dimensional gel electrophoresis LCMS/MS and two-dimensional gel electrophoresis MALDI MS/MS analysis.

    PubMed

    Singh, Sachin K; Lakshmi, Mula G Meena; Saxena, Sandeep; Swamy, Cherukuvada V Brahmendra; Idris, Mohammed M

    2011-01-01

    Zebrafish (Danio rerio) is the widely used vertebrate model animal for understanding the complexity of development and disease process. Zebrafish has been also extensively used in understanding the mechanism of regeneration for its extensive capability of regenerating fins and other tissues. We have analyzed the proteome profile of zebrafish caudal fin in its native state based on one-dimensional gel electrophoresis LCMS/MS and two-dimensional gel electrophoresis MS/MS analyses. A total of 417 proteins were identified as zebrafish fin tissue specific, which includes 397 proteins identified based on one-dimensional gel electrophoresis LCMS/MS analysis and 101 proteins identified based on two-dimensional gel electrophoresis MALDI MS/MS. The proteins mapped to the zebrafish fin tissue were shown to be involved in various biological activities related to development, apoptosis, signaling and metabolic process. Focal adhesion, regulation of actin cytoskeleton, cancer-related pathways, mitogen-activated protein kinase signaling, antigen processing and presentation, and proteasome are some of the important pathways associated with the identified proteome data set of the zebrafish fin.

  19. High-resolution MS, MS/MS, and UV database of fungal secondary metabolites as a dereplication protocol for bioactive natural products.

    PubMed

    El-Elimat, Tamam; Figueroa, Mario; Ehrmann, Brandie M; Cech, Nadja B; Pearce, Cedric J; Oberlies, Nicholas H

    2013-09-27

    A major problem in the discovery of new biologically active compounds from natural products is the reisolation of known compounds. Such reisolations waste time and resources, distracting chemists from more promising leads. To address this problem, dereplication strategies are needed that enable crude extracts to be screened for the presence of known compounds before isolation efforts are initiated. In a project to identify anticancer drug leads from filamentous fungi, a significant dereplication challenge arises, as the taxonomy of the source materials is rarely known, and, thus, the literature cannot be probed to identify likely known compounds. An ultraperformance liquid chromatography-photodiode array-high-resolution tandem mass spectrometric (UPLC-PDA-HRMS-MS/MS) method was developed for dereplication of fungal secondary metabolites in crude culture extracts. A database was constructed by recording HRMS and MS/MS spectra of fungal metabolites, utilizing both positive- and negative-ionization modes. Additional details, such as UV-absorption maxima and retention times, were also recorded. Small-scale cultures that showed cytotoxic activities were dereplicated before engaging in the scale-up or purification processes. Using these methods, approximately 50% of the cytotoxic extracts could be eliminated from further study after the confident identification of known compounds. The specific attributes of this dereplication methodology include a focus on bioactive secondary metabolites from fungi, the use of a 10 min chromatographic method, and the inclusion of both HRMS and MS/MS data.

  20. 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.

  1. Analysis of agricultural residues on tea using d-SPE sample preparation with GC-NCI-MS and UHPLC-MS/MS.

    PubMed

    Zhang, Xian; Mobley, Nicole; Zhang, Jiugen; Zheng, Xiaomin; Lu, Ling; Ragin, Oscar; Smith, Christopher J

    2010-11-24

    This study presents new sample preparation and analytical procedures for the quantification of pesticides on processed tea leaves. The new method includes tea extraction and dispersive solid phase extraction (d-SPE) to prepare gas chromatography (GC) and ultrahigh-performance liquid chromatography (UHPLC)-ready samples, providing a fast and cost-effective solution for time-sensitive industrial analysis to fulfill regulatory requirements. Both GC-negative chemical ionization mass spectrometry (GC-NCI-MS) and UHPLC-tandem mass spectrometry (UHPLC-MS/MS) were employed to produce highly sensitive and reproducible data. Excellent limits of detection (typically below 1 μg/kg for GC and 10 μg/kg for UHPLC), wide linearity ranges, and good recoveries (mostly >70%) were achieved on the selected pesticides. Twenty-seven tea samples purchased from local grocery stores were analyzed using the newly developed methods. Among the pesticides analyzed, endosulfan sulfate and kelthane were the most frequently detected by GC-NCI-MS and imidacloprid and acetamiprid by UHPLC-MS/MS in these teas. The samples were found to be relatively clean, with <1 mg/kg of total pesticide residues. The organic-labeled teas were significantly cleaner than nonorganic ones. The cost per gram of tea did not correlate with pesticide residue levels detected.

  2. 56. MISSISSIPPI, NOXUBEE CO. MACON HIGHWAY BRIDGE Ms. 14, 6 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. MISSISSIPPI, NOXUBEE CO. MACON HIGHWAY BRIDGE Ms. 14, 6 miles E to McLeod, 4.5 miles S on McLeod-Shuqualak road. Mahorner's bridge (1884). View from E approach. Sarcone Photography, Atlanta, Ga. Aug. 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  3. Liquid MALDI MS Analysis of Complex Peptide and Proteome Samples.

    PubMed

    Wiangnon, Kanjana; Cramer, Rainer

    2016-09-02

    Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) is well-known to be a powerful technique for the analysis of biological samples. By using glycerol-based liquid support matrices (LSMs) instead of conventional MALDI matrices the power of this technique can be extended further. In this study, we exploited LSMs for the identification of complex samples, that is, the Lactobacillus proteome and a bovine serum albumin (BSA) digest. Liquid and solid MALDI samples were manually and robotically prepared by coupling a nanoflow high-performance liquid chromatography (nanoHPLC) system to an automated MALDI sample spotting device. MS and MS/MS data were successfully acquired at the femtomole level using TOF/TOF as well as Q-TOF instrumentation and used for protein identification searching sequence databases. For the BSA digest analysis, liquid MALDI samples resulted in peptide mass fingerprints, which led to a higher confidence in protein identification compared with solid (crystalline) MALDI samples; however, postsource decay (PSD) MS/MS analysis of both the proteome of Lactobacillus plantarum WCFS1 cells and BSA digest showed that further optimization of the formation and detection of peptide fragment ions is still needed for liquid MALDI samples, as the MS/MS ion search score was lower than that for the solid MALDI samples, reflecting the poorer quality of the liquid MALDI-PSD spectra, which can be attributed to the differences in PSD parameters and their optimization that is currently achievable.

  4. The Dominant Ms Allele in Onion Shows Reduced Penetrance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most commonly used source of cytoplasmic male sterility in onion is controlled by the interaction of the cytoplasm [male-sterile (S) or normal (N) male-fertile] and one nuclear male-fertility-restoration locus (Ms). Scoring of genotypes at Ms is generally done by testcrossing male-fertile to mal...

  5. The Ms. Stereotype Revisited: Implicit and Explicit Facets

    ERIC Educational Resources Information Center

    Malcolmson, Kelly A.; Sinclair, Lisa

    2007-01-01

    Implicit and explicit stereotypes toward the title Ms. were examined. Participants read a short description of a target person whose title of address varied (Ms., Mrs., Miss, Mr.). They then rated the person on agentic and communal traits and completed an Implicit Association Test. Replicating earlier research (Dion, 1987), at an explicit level,…

  6. Investigation of Imposter Perfumes Using GC-MS

    ERIC Educational Resources Information Center

    Mowery, Kelly A.; Blanchard, Daniel E.; Smith, Stephanie; Betts, Thomas A.

    2004-01-01

    An experiment to initiate students into several features of gas chromatograph-mass spectrometers (GC-MS) through the study of branded and counterfeit perfumes is described. The experiment enables the students to appreciate the power of GC-MS in distinguishing between original and imitation perfumes, and in analyzing data with its application…

  7. Rapid quantification of 14 saponins of Maesa lanceolata by UPLC-MS/MS.

    PubMed

    Foubert, K; Cuyckens, F; Vleeschouwer, K; Theunis, M; Vlietinck, A; Pieters, L; Apers, S

    2010-06-15

    Saponins are high molecular weight glycosides which are known for their broad range of biological activities. In case of Maesa lanceolata, a tree growing in African countries, the maesasaponins showed virucidal, haemolytic, molluscicidal and anti-angiogenic activity. Since the different activities are dependent on the structure of the saponins, a method was developed and validated for the analysis of the individual saponins in this plant. Since the saponins were only present in small amounts, it was necessary to develop a very sensitive analytical method. For the fast and sensitive analysis of the extracted and purified plant samples ultra-performance liquid chromatography was coupled to a triple quadrupole mass spectrometer for MS/MS detection. A method in positive ESI mode, using sodium acetate in the mobile phase, was developed. The sodium adduct ion was selected as the precursor ion since it provided better sensitivity and a better, more stable fragmentation compared to the deprotonated and protonated ions. The intensity of the signal obtained by fragmentation of the sodium adducts of the saponins, was optimized by the addition of different concentrations of sodium acetate to the mobile phase. Reference standards were not available for all 14 saponins. Therefore, a relative MS/UV response was calculated allowing the estimation of the saponins in real samples. alpha-Hederin was used as external standard. The method was linear over the investigated concentration range with a good correlation coefficient (>0.99). The intra- and inter-day precisions were below 15% for most maesasaponins with the exception of maesasaponin II, which showed a precision within 20%. The recoveries of the spiked pure compounds maesasaponin IV.1 and VII.1 were 96.6% and 85.5%, respectively. The validated method can be applied in the investigation of the content of 14 saponins in transgenic and non-transgenic plant material of M. lanceolata.

  8. Peptide sequence motif analysis of tandem MS data with the SALSA algorithm.

    PubMed

    Liebler, Daniel C; Hansen, Beau T; Davey, Sean W; Tiscareno, Laura; Mason, Daniel E

    2002-01-01

    We have developed a pattern recognition algorithm called SALSA (scoring algorithm for spectral analysis) for the detection of specific features in tandem MS (MS-MS) spectra. Application of the SALSA algorithm to the detection of peptide MS-MS ion series enables identification of MS-MS spectra displaying characteristics of specific peptide sequences. SALSA analysis scores MS-MS spectra based on correspondence between theoretical ion series for peptide sequence motifs and actual MS-MS product ion series, regardless of their absolute positions on the m/z axis. Analyses of tryptic digests of bovine serum albumin (BSA) by LC-MS-MS followed by SALSA analysis detected MS-MS spectra for both unmodified and multiple modified forms of several BSA tryptic peptides. SALSA analysis of MS-MS data from mixtures of BSA and human serum albumin (HSA) tryptic digests indicated that ion series searches with BSA peptide sequence motifs identified MS-MS spectra for both BSA and closely related HSA peptides. Optimal discrimination between MS-MS spectra of variant peptide forms is achieved when the SALSA search criteria are optimized to the target peptide. Application of SALSA to LC-MS-MS proteome analysis will facilitate the characterization of modified and sequence variant proteins.

  9. Quantitative performance of a quadrupole-orbitrap-MS in targeted LC-MS determinations of small molecules.

    PubMed

    Grund, Baptiste; Marvin, Laure; Rochat, Bertrand

    2016-05-30

    High-resolution mass spectrometry (HRMS) has been associated with qualitative and research analysis and QQQ-MS with quantitative and routine analysis. This view is now challenged and for this reason, we have evaluated the quantitative LC-MS performance of a new high-resolution mass spectrometer (HRMS), a Q-orbitrap-MS, and compared the results obtained with a recent triple-quadrupole MS (QQQ-MS). High-resolution full-scan (HR-FS) and MS/MS acquisitions have been tested with real plasma extracts or pure standards. Limits of detection, dynamic range, mass accuracy and false positive or false negative detections have been determined or investigated with protease inhibitors, tyrosine kinase inhibitors, steroids and metanephrines. Our quantitative results show that today's available HRMS are reliable and sensitive quantitative instruments and comparable to QQQ-MS quantitative performance. Taking into account their versatility, user-friendliness and robustness, we believe that HRMS should be seen more and more as key instruments in quantitative LC-MS analyses. In this scenario, most targeted LC-HRMS analyses should be performed by HR-FS recording virtually "all" ions. In addition to absolute quantifications, HR-FS will allow the relative quantifications of hundreds of metabolites in plasma revealing individual's metabolome and exposome. This phenotyping of known metabolites should promote HRMS in clinical environment. A few other LC-HRMS analyses should be performed in single-ion-monitoring or MS/MS mode when increased sensitivity and/or detection selectivity will be necessary.

  10. UPLC-MS/MS determination of florfenicol and florfenicol amine antimicrobial residues in tilapia muscle.

    PubMed

    Orlando, Eduardo Adilson; Costa Roque, Aline Gabriela; Losekann, Marcos Eliseu; Colnaghi Simionato, Ana Valéria

    2016-11-01

    Despite the benefits to fish farmers, the use of antimicrobials in aquaculture has concerned consumers and competent authorities. The indiscriminate use of such substances promotes the emergence of resistant microorganisms, decreases the effectiveness of treatments, and causes possible toxic effects in humans. In Brazil, florfenicol is the only antimicrobial registered for use in aquaculture and is often used in tilapia in cage creation. Thus, this study aimed to develop a method for determination of florfenicol residues and its metabolite florfenicol amine in tilapia fillet by UPLC-MS/MS. Analytes were extracted with ethyl acetate, followed by liquid-liquid partition clean-up with hexane and SPE. The sorbents C18, phenyl and HLB-Oasis were evaluated by SPE. Phenyl sorbent showed the best results, and the extraction conditions were optimized in the sample matrix with fractional factorial design 2(4-1). The analytes were separated on a C18 chromatographic column (50×2.1mm×1.7μm) using water (A) and acetonitrile (B) as mobile phase at a flow rate of 0.3mLmin(-1) with a linear gradient (in% B): 0-2.0min: 20%; 2.0-2.5min: increase to 90%; 2.5-3.5min: 90%; 3.0-3.5min: decrease to 20%; 4.0-5.0min: 20%. The analytes were monitored in a MS/MS triple quadrupole system by MRM mode with transitions at m/z 356.1>336.1 (florfenicol) and m/z 248.1>130.1 (florfenicol amine). The optimized method was validated obtaining LOQ values of 3 and 25ngg(-1) for florfenicol and florfenicol amine, respectively, precision between 20 and 36%, absolute extraction efficiency between 38 and 80%, and adequate linearity. The method was applied to samples intended for human consumption, and within the 15 evaluated samples, only one showed florfenicol residue at 30ngg(-1), which is below the maximum residue limit established in Brazil.

  11. Quantitation of sirolimus using liquid chromatography-tandem mass spectrometry (LC-MS-MS).

    PubMed

    Korecka, Magdalena; Shaw, Leslie M

    2010-01-01

    A multiple reaction monitoring positive ion HPLC method with tandem mass spectrometric detection (MS-MS) for determination of sirolimus in human blood samples is described. This method utilizes an online cleanup step that provides simple and rapid sample preparation with a switching valve technique. This procedure includes: instrumentation, API 3000 triple quadrupole with turbo-ion spray (Applied Biosystems, Foster City, CA); HPLC system (Agilent Technologies series 1100, Wilmington, DE); two position switching valve (Valco, Houston, TX); 10 mm guard cartridge (C(18)) used as an extraction column (Perkin Elmer, Norwalk, CT); analytical column (Nova-Pak C(18) column, 2.1 x 150 mm I.D., 4 microm, Waters Corp, Milford, MA) maintained at 65 degrees C; extraction solution, ammonium acetate (30 mM, pH 5.2), flow rate 1.0 mL/min; eluting solution, methanol:30 mM ammonium acetate buffer (pH 5.2, 97:3 v/v), flow rate 0.8 mL/min with 1/3 of the flow split post-column into the MS-MS; total run-time 3.5 min. Sample preparation is based on simple protein precipitation with a mixture of methanol and zinc sulfate (7:3, v/v) followed by online sample cleanup. This procedure provides a decreased sample preparation time by a factor of four compared to a method that uses an SPE column. The first and third quadrupoles were set to detect the ammonium adduct ion and a high mass fragment of sirolimus (m/z 931.8-->864.6), and of an internal standard (ascomycin) (m/z 809.5-->756.5). The lower limit of quantification of this method is 2.5 microg/L. The quantification of drug is made from standard curve using peak-area ratio of analyte vs. internal standard. Calibration curve is constructed using non-weighted linear through zero regression.

  12. Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS

    NASA Technical Reports Server (NTRS)

    Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

    2007-01-01

    Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV < 0.5 %. The intra-day and inter-day CVs are < 15 % for quality control samples with concentrations of 75, 300, 750 and 3000 pg/mL of scopolamine in human saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS

  13. Identification of flea species using MALDI-TOF/MS.

    PubMed

    Yssouf, Amina; Socolovschi, Cristina; Leulmi, Hamza; Kernif, Tahar; Bitam, Idir; Audoly, Gilles; Almeras, Lionel; Raoult, Didier; Parola, Philippe

    2014-05-01

    In the present study, a molecular proteomics (MALDI-TOF/MS) approach was used as a tool for identifying flea vectors. We measured the MS spectra from 38 flea specimens of 5 species including Ctenocephalides felis, Ctenocephalides canis, Archaeopsylla erinacei, Xenopsylla cheopis and Stenoponia tripectinata. A blind test performed with 24 specimens from species included in a library spectral database confirmed that MALDI-TOF/MS is an effective tool for discriminating flea species. Although fresh and 70% ethanol-conserved samples subjected to MALDI-TOF/MS in blind tests were correctly classified, only MS spectra of quality from fresh specimens were sufficient for accurate and significant identification. A cluster analysis highlighted that the MALDI Biotyper can be used for studying the phylogeny of fleas.

  14. Coumarin tags for analysis of peptides by MALDI-TOF MS and MS/MS. 2. Alexa Fluor 350 tag for increased peptide and protein Identification by LC-MALDI-TOF/TOF MS.

    PubMed

    Pashkova, Anna; Chen, Hsuan-Shen; Rejtar, Tomas; Zang, Xin; Giese, Roger; Andreev, Victor; Moskovets, Eugene; Karger, Barry L

    2005-04-01

    The goal of this study was the development of N-terminal tags to improve peptide identification using high-throughput MALDI-TOF/TOF MS. Part 1 of the study was focused on the influence of derivatization on the intensities of MALDI-TOF MS signals of peptides. In part 2, various derivatization approaches for the improvement of peptide fragmentation efficiency in MALDI-TOF/TOF MS are explored. We demonstrate that permanent cation tags, while significantly improving signal intensity in the MS mode, lead to severe suppression of MS/MS fragmentation, making these tags unsuitable for high-throughput MALDI-TOF/TOF MS analysis. In the present work, it was found that labeling with Alexa Fluor 350, a coumarin tag containing a sulfo group, along with guanidation of epsilon-amino groups of Lys, could enhance unimolecular fragmentation of peptides with the formation of a high-intensity y-ion series, while the peptide intensities in the MS mode were not severely affected. LC-MALDI-TOF/TOF MS analysis of tryptic peptides from the SCX fractions of an E. coli lysate revealed improved peptide scores, a doubling of the total number of peptides, and a 30% increase in the number of proteins identified, as a result of labeling. Furthermore, by combining the data from native and labeled samples, confidence in correct identification was increased, as many proteins were identified by different peptides in the native and labeled data sets. Additionally, derivatization was found not to impair chromatographic behavior of peptides. All these factors suggest that labeling with Alexa Fluor 350 is a promising approach to the high-throughput LC-MALDI-TOF/TOF MS analysis of proteomic samples.

  15. Iron stabilizes thylakoid protein-pigment complexes in Indian mustard during Cd-phytoremediation as revealed by BN-SDS-PAGE and ESI-MS/MS.

    PubMed

    Qureshi, M Irfan; D'Amici, Gian Maria; Fagioni, Marco; Rinalducci, Sara; Zolla, Lello

    2010-07-01

    Two-dimensional BN-SDS-PAGE, ESI-MS/MS and electron microscopy (EM) were used to study the role of iron (Fe) under cadmium (Cd) stress in retention of thylakoidal multiprotein complexes (MPCs) and chloroplast ultrastructure of Indian mustard, a moderate hyperaccumulator plant. Mustard was grown hydroponically with or without iron for 17 days and then exposed to CdCl2 for 3 days. Fe deficiency led to an increase in oxidative stress and damage to chloroplast/thylakoids accompanied by a decrease in chlorophyll content; exposure of plants to Cd further enhanced the oxidative stress and Cd accumulation (more in -Fe plants). However, the presence of iron aided plants in the suppression of oxidative stress and retention of chloroplasts and chlorophylls under Cd stress. Proteomic analyses by 2D BN-SDS-PAGE and mass spectrometry showed that Fe deficiency considerably decreased the amount of LHCII trimer, ATPase-F1 portion, cyt b6/f and RuBisCO. No or less reduction, was observed for PSI(RCI+LHCI), the PSII-core monomer, and the PSII subcomplex, while an increase in the LHCII monomer was noted. Under iron deficiency, Cd proved to be very deleterious to MPCs, except for the PSII subcomplex, the LHCII monomer and free proteins which were increased. Iron proved to be very protective in retaining almost all the complexes. MPCs showed greater susceptibility to Cd than Fe deficiency, mainly at the level of RuBisCO and cyt b6/f; an increase in the amount of the PSII subcomplex, LHCII monomer and free proteins indicates differences in the mechanisms affected by Fe deficiency and Cd stress when compared to Fe-fed plants. This study furthers our understanding of the sites actually damaged in MPCs under Fe deficiency and Cd stress. A role emerges for iron in the protection of MPCs and, hence, of the chloroplast. The present study also indicates the importance of iron for efficient phytoextraction/phytoremediation.

  16. Development of a UHPLC-MS/MS method for the measurement of chlortetracycline degradation in swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed capable of simultaneously measuring chlortetracycline (CTC), epi-chlortetracycline (epi-CTC), isochlortetracycline (ICTC), oxytetracycline, and tetracycline in swine manure. A simple sample pr...

  17. Development of a UHPLC-MS/MS method for the measurement of chlortetracycline degradation in swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed capable of simultaneously measuring chlortetracycline (CTC), epi-chlortetracycline (epi-CTC) and isochlortetracycline (ICTC), as well as other structurally related tetracyclines in swine manur...

  18. Male Sex Is Independently Associated with Faster Disability Accumulation in Relapse-Onset MS but Not in Primary Progressive MS

    PubMed Central

    Ribbons, Karen Ann; McElduff, Patrick; Boz, Cavit; Trojano, Maria; Izquierdo, Guillermo; Duquette, Pierre; Girard, Marc; Grand’Maison, Francois; Hupperts, Raymond; Grammond, Pierre; Oreja-Guevara, Celia; Petersen, Thor; Bergamaschi, Roberto; Giuliani, Giorgio; Barnett, Michael; van Pesch, Vincent; Amato, Maria-Pia; Iuliano, Gerardo; Fiol, Marcela; Slee, Mark; Verheul, Freek; Cristiano, Edgardo; Fernandez-Bolanos, Ricardo; Saladino, Maria-Laura; Rio, Maria Edite; Cabrera-Gomez, Jose; Butzkueven, Helmut; van Munster, Erik; Den Braber-Moerland, Leontien; La Spitaleri, Daniele; Lugaresi, Alessandra; Shaygannejad, Vahid; Gray, Orla; Deri, Norma; Alroughani, Raed; Lechner-Scott, Jeannette

    2015-01-01

    Background Multiple Sclerosis is more common in women than men and females have more relapses than men. In a large international cohort we have evaluated the effect of gender on disability accumulation and disease progression to determine if male MS patients have a worse clinical outcome than females. Methods Using the MSBase Registry, data from 15,826 MS patients from 25 countries was analysed. Changes in the severity of MS (EDSS) were compared between sexes using a repeated measures analysis in generalised linear mixed models. Kaplan-Meier analysis was used to test for sex difference in the time to reach EDSS milestones 3 and 6 and the secondary progressive MS. Results In relapse onset MS patients (n = 14,453), males progressed significantly faster in their EDSS than females (0.133 vs 0.112 per year, P<0.001,). Females had a reduced risk of secondary progressive MS (HR (95% CI) = 0.77 (0.67 to 0.90) P = 0.001). In primary progressive MS (n = 1,373), there was a significant increase in EDSS over time in males and females (P<0.001) but there was no significant sex effect on the annualized rate of EDSS change. Conclusion Among registrants of MSBase, male relapse-onset patients accumulate disability faster than female patients. In contrast, the rate of disability accumulation between male and female patients with primary progressive MS is similar. PMID:26046348

  19. Metabolomic and elemental analysis of camel and bovine urine by GC-MS and ICP-MS.

    PubMed

    Ahamad, Syed Rizwan; Alhaider, Abdul Qader; Raish, Mohammad; Shakeel, Faiyaz

    2017-01-01

    Recent studies from the author's laboratory indicated that camel urine possesses antiplatelet activity and anti-cancer activity which is not present in bovine urine. The objective of this study is to compare the volatile and elemental components of bovine and camel urine using GC-MS and ICP-MS analysis. We are interested to know the component that performs these biological activities. The freeze dried urine was dissolved in dichloromethane and then derivatization process followed by using BSTFA for GC-MS analysis. Thirty different compounds were analyzed by the derivatization process in full scan mode. For ICP-MS analysis twenty eight important elements were analyzed in both bovine and camel urine. The results of GC-MS and ICP-MS analysis showed marked difference in the urinary metabolites. GC-MS evaluation of camel urine finds a lot of products of metabolism like benzene propanoic acid derivatives, fatty acid derivatives, amino acid derivatives, sugars, prostaglandins and canavanine. Several research reports reveal the metabolomics studies on camel urine but none of them completely reported the pharmacology related metabolomics. The present data of GC-MS suggest and support the previous studies and activities related to camel urine.

  20. Dual parallel mass apectrometry (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, phospholipids, and fat-soluble vitamins. Since no one technique is by itself idea...

  1. 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...

  2. Simultaneous determination of structurally diverse compounds in different Fangchi species by UHPLC-DAD and UHPLC-ESI-MS/MS.

    PubMed

    Sim, Hee-Jung; Kim, Ji Hee; Lee, Kang Ro; Hong, Jongki

    2013-05-07

    Two bisbenzylisoquinoline alkaloids, two morphine alkaloids, one aporphine alkaloid, syringaresinol and aristolochic acid І were selected as marker compounds and simultaneously analyzed using an ultra-high pressure liquid chromatography-diode array detection (UHPLC-DAD) method. These marker compounds were used for the quality control of Fangchi species of different origins, including Sinomenium acutum, Stephania tetrandra, Cocculus trilobus and Aristolochia fangchi. A reversed-phase UHPLC-DAD method was developed and validated for the simultaneous quantification of structurally diverse markers in different Fangchi species. In addition, an UHPLC-electrospray ionization tandem mass spectrometry (ESI-MS/MS) method was used for marker identification in Fangchi species, which provided diagnostic MS/MS spectral patterns that were dependent upon the marker structures. The UHPLC-MS/MS data were used to confirm and complement the UHPLC-DAD quality evaluation results. Additionally, magnoflorine and syringaresinol were observed for the first time in S. tetrandra and C. trilobus, respectively. Twenty different Fangchi species samples were analyzed for aristolochic acid I, syringaresinol and the alkaloids using the UHPLC-DAD and MS/MS method. Based on the levels of markers and principal component analysis (PCA), this method allowed for the clear classification of the samples into four different groups representing samples originating from the four species.

  3. Ms.ing the Free Press: The Advertising and Editorial Content of "Ms." Magazine, 1972-1992.

    ERIC Educational Resources Information Center

    McKinnon, Lori Melton

    1994-01-01

    Uses content analysis to show that, although "Ms." magazine sometimes compromised its promise to be a mass-mediated forum for feminist debate, its current format (ad-free, to do away with conflicts experienced between editors' ideology and advertisers' wishes) has allowed "Ms." to present a renewed vision of feminism. (SR)

  4. Matrix effects break the LC behavior rule for analytes in LC-MS/MS analysis of biological samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are generally accepted as the preferred techniques for detecting and quantitating analytes of interest in biological matrices on the basis of the rule that one chemical compound yields one LC-...

  5. Analysis of glucosinolates, isothiocyanates, and amine degradation products in vegetable extracts and blood plasma by LC-MS/MS.

    PubMed

    Song, Lijiang; Morrison, John J; Botting, Nigel P; Thornalley, Paul J

    2005-12-15

    Dietary glucosinolates are under intensive investigation as precursors of cancer-preventive isothiocyanates. Quantitation of the dose and bioavailability of glucosinolates and isothiocyanates requires a comprehensive analysis of the major dietary glucosinolates, isothiocyanates, and related metabolites. We report a liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) analytical method for the comprehensive analysis of the seven major dietary glucosinolates, related isothiocyanates, and putative amine degradation products. The parent glucosinolates were sinigrin, gluconapin, progoitrin, glucoiberin, glucoraphanin, glucoalyssin, and gluconasturtiin. The LC-MS/MS analysis method for these compounds was developed and validated; a standard addition analysis protocol was used generally to avoid the requirement for stable isotopic standards. Where stable isotopic standards were available, internal standardization with these gave estimates in agreement with those obtained by the standard addition analysis protocol. For glucosinolates, negative ion electrospray LC-MS/MS analysis was performed. Isothiocyanates and amines were prederivatized to the corresponding thiourea and N-acetamides, respectively, and were quantified by positive ion electrospray LC-MS/MS. The limits of detection were 0.5-2 pmol; the recoveries for glucosinolates, isothiocyanates, and amines were 85-90%, 50-85%, and 60-70%, respectively; and the intra- and interbatch coefficients of variation were 1-4% and 3-10%, respectively. These methods provide facile access to comprehensive analytical data on the major dietary glucosinolates and related metabolites to quantify inputs and metabolic formation of these compounds in cancer prevention and related studies.

  6. QUANTIFICATION OF 2,4-D ON SOLID-PHASE EXPOSURE SAMPLING MEDIA BY LC/MS/MS

    EPA Science Inventory

    Three types of solid phase chemical exposure sampling media: cellulose, polyurethane foam (PUF) and XAD-2, were analyzed for 2,4-D and the amine salts of 2,4-D. Individual samples were extracted into acidified methanol and the extracts were analyzed via LC/MS/MS using electrospra...

  7. DETERMINATION OF ECOLOGICALLY RELEVANT PHARMACEUTICALS AND THEIR SELECTED METABOLITES IN EFFLUENT AND SURFACE WATER USING UPLC/MS/MS

    EPA Science Inventory

    Objective is to develop analytical methods including SPE and UPLC/MS/MS needed to analyze over 60 human prescription pharamceuticals and metabolites belonging to a multitude of different classes in surface waters and wastewater effluent. The methods will be used in future studies...

  8. Structural Feature Ions for Distinguishing N- and O-Linked Glycan Isomers by LC-ESI-IT MS/MS

    NASA Astrophysics Data System (ADS)

    Everest-Dass, Arun V.; Abrahams, Jodie L.; Kolarich, Daniel; Packer, Nicolle H.; Campbell, Matthew P.

    2013-06-01

    Glycomics is the comprehensive study of glycan expression in an organism, cell, or tissue that relies on effective analytical technologies to understand glycan structure-function relationships. Owing to the macro- and micro-heterogeneity of oligosaccharides, detailed structure characterization has required an orthogonal approach, such as a combination of specific exoglycosidase digestions, LC-MS/MS, and the development of bioinformatic resources to comprehensively profile a complex biological sample. Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) has emerged as a key tool in the structural analysis of oligosaccharides because of its high sensitivity, resolution, and robustness. Here, we present a strategy that uses LC-ESI-MS/MS to characterize over 200 N- and O-glycans from human saliva glycoproteins, complemented by sequential exoglycosidase treatment, to further verify the annotated glycan structures. Fragment-specific substructure diagnostic ions were collated from an extensive screen of the literature available on the detailed structural characterization of oligosaccharides and, together with other specific glycan structure feature ions derived from cross-ring and glycosidic-linkage fragmentation, were used to characterize the glycans and differentiate isomers. The availability of such annotated mass spectrometric fragmentation spectral libraries of glycan structures, together with such substructure diagnostic ions, will be key inputs for the future development of the automated elucidation of oligosaccharide structures from MS/MS data.

  9. Rapid, Potentially Automatable, Method Extract Biomarkers for HPLC/ESI/MS/MS to Detect and Identify BW Agents

    DTIC Science & Technology

    1997-11-01

    status can sometimes be reflected in the infectious potential or drug resistance of those pathogens. For example, in Mycobacterium tuberculosis ... Mycobacterium tuberculosis , its antibiotic resistance and prediction of pathogenicity amongst Mycobacterium spp. based on signature lipid biomarkers ...TITLE AND SUBTITLE Rapid, Potentially Automatable, Method Extract Biomarkers for HPLC/ESI/MS/MS to Detect and Identify BW Agents 5a. CONTRACT NUMBER 5b

  10. Staphylococcus aureus methicillin resistance detected by HPLC-MS/MS targeted metabolic profiling.

    PubMed

    Schelli, Katie; Rutowski, Joshua; Roubidoux, Julia; Zhu, Jiangjiang

    2017-03-15

    Recently, novel bioanalytical methods, such as NMR and mass spectrometry based metabolomics approaches, have started to show promise in providing rapid, sensitive and reproducible detection of Staphylococcus aureus antibiotic resistance. Here we performed a proof-of-concept study focused on the application of HPLC-MS/MS based targeted metabolic profiling for detecting and monitoring the bacterial metabolic profile changes in response to sub-lethal levels of methicillin exposure. One hundred seventy-seven targeted metabolites from over 20 metabolic pathways were specifically screened and one hundred and thirty metabolites from in vitro bacterial tests were confidently detected from both methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA, respectively). The metabolic profiles can be used to distinguish the isogenic pairs of MSSA strains from MRSA strains, without or with sub-lethal levels of methicillin exposure. In addition, better separation between MSSA and MRSA strains can be achieved in the latter case using principal component analysis (PCA). Metabolite data from isogenic pairs of MSSA and MRSA strains were further compared without and with sub-lethal levels of methicillin exposure, with metabolic pathway analyses additionally performed. Both analyses suggested that the metabolic activities of MSSA strains were more susceptible to the perturbation of the sub-lethal levels of methicillin exposure compared to the MRSA strains.

  11. Determination of lipophilic toxins by LC/MS/MS: single-laboratory validation.

    PubMed

    Villar-González, Adriano; Rodríguez-Velasco, María Luisa; Gago-Martínez, Ana

    2011-01-01

    An LC/MS/MS method has been developed, assessed, and intralaboratory-validated for the analysis of the lipophilic toxins currently regulated by European Union legislation: okadaic acid (OA) and dinophysistoxins 1 and 2, including their ester forms; azaspiracids 1, 2, and 3; pectenotoxins 1 and 2; yessotoxin (YTX), and the analogs 45 OH-YTX, Homo YTX, and 45 OH-Homo YTX; as well as for the analysis of 13-desmetil-spirolide C. The method consists of duplicate sample extraction with methanol and direct analysis of the crude extract without further cleanup or concentration. Ester forms of OA and dinophysistoxins are detected as the parent ions after alkaline hydrolysis of the extract. The validation process of this method was performed using both fortified and naturally contaminated samples, and experiments were designed according to International Organization for Standardization, International Union of Pure and Applied Chemistry, and AOAC guidelines. With the exception of YTX in fortified samples, RSDr below 15% and RSDR were below 25%. Recovery values were between 77 and 95%, and LOQs were below 60 microg/kg. These data together with validation experiments for recovery, selectivity, robustness, traceability, and linearity, as well as uncertainty calculations, are presented in this paper.

  12. Determination of eight pesticides in Lycium barbarum by LC-MS/MS and dietary risk assessment.

    PubMed

    Fu, Yan; Yang, Ting; Zhao, Jian; Zhang, Liang; Chen, Ruoxia; Wu, Yinliang

    2017-03-01

    A LC-MS/MS method for determination of eight pesticides (triadimefon, sulfoxaflor, flusilazole, tebuconazole, difenoconazole, amitraz, azoxystrobin, and thiophanate-methyl) in Lycium barbarum was established. The samples were extracted with acetonitrile, and then cleaned up by primary secondary amine. The extracts were diluted with 0.1% formic acid in water. The results showed that at the fortified levels of 0.01-10mg/kg, the average recoveries of these pesticides ranged from 82.1% to 96.2% with the relative standard deviations lower than 7%. The half-lives of eight pesticides were 1.3-5.0days in Lycium barbarum fruits. The pre-harvest interval of all pesticides mentioned above were investigated. Tebuconazole (14days), sulfoxaflor (14days) and flusilazole (28days) have longer pre-harvest interval than the others which have 7days. The dietary risks, assessed as hazard quotients, were far below 100%. The results showed that the eight pesticides applied to Lycium barbarum were comparably safe for the consumer.

  13. Monitoring of chronic Cannabis abuse: an LC-MS/MS method for hair analysis.

    PubMed

    Mercolini, Laura; Mandrioli, Roberto; Protti, Michele; Conti, Matteo; Serpelloni, Giovanni; Raggi, Maria Augusta

    2013-03-25

    An advanced analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS), has been developed for the identification and determination in hair of Δ(9)-tetrahydrocannabinol together with its major metabolite 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol. Since the latter is formed endogenously, it allows the assessment of chronic use excluding passive exposure to Cannabis. The sample pre-treatment procedure is based on a feasible incubative extraction followed by a liquid-liquid extraction step. Chromatographic separation was performed using a reversed-phase column and gradient elution with a formic acid/acetonitrile/water mobile phase. The limits of quantitation and of detection were 3pg/mg and 1pg/mg, respectively, for both analytes. The method was successfully applied to the analysis of hair samples from Cannabis abusers; the analyte concentrations found ranged from 55 to 100pg/mg for Δ(9)-tetrahydrocannabinol and from 5 to 10pg/mg for 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol. Accuracy studies also gave satisfactory results (recovery>87%), thus confirming the suitability of the assay for chronic consumption monitoring.

  14. A simple, fast and sensitive screening LC-ESI-MS/MS method for antibiotics in fish.

    PubMed

    Guidi, Letícia Rocha; Santos, Flávio Alves; Ribeiro, Ana Cláudia S R; Fernandes, Christian; Silva, Luiza H M; Gloria, Maria Beatriz A

    2017-01-15

    The objective of this study was to develop and validate a fast, sensitive and simple liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the screening of six classes of antibiotics (aminoglycosides, beta-lactams, macrolides, quinolones, sulfonamides and tetracyclines) in fish. Samples were extracted with trichloroacetic acid. LC separation was achieved on a Zorbax Eclipse XDB C18 column and gradient elution using 0.1% heptafluorobutyric acid in water and acetonitrile as mobile phase. Analysis was carried out in multiple reaction monitoring mode via electrospray interface operated in the positive ionization mode, with sulfaphenazole as internal standard. The method was suitable for routine screening purposes of 40 antibiotics, according to EC Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines, taking into consideration threshold value, cut-off factor, detection capability, limit of detection, sensitivity and specificity. Real fish samples (n=193) from aquaculture were analyzed and 15% were positive for enrofloxacin (quinolone), one of them at a higher concentration than the level of interest (50µgkg(-1)), suggesting possible contamination or illegal use of that antibiotic.

  15. [Determination of Amantadine in Poultry Tissues and Egg by LC-MS/MS].

    PubMed

    Tsuruoka, Yumi; Nakajima, Takayuki; Hashimoto, Tsuneo; Kanda, Maki; Hayashi, Hiroshi; Matsushima, Youko; Yoshikawa, Souichi; Nagano, Chieko; Okutomi, Yuki; Takano, Ichiro

    2015-01-01

    An accurate and selective analytical method for amantadine, which is used as antiviral drug to treat influenza A virus infection, was developed using LC-MS/MS. Residual amantadine was extracted from 4 kinds of food sample (poultry muscle, liver, gizzard and egg) with acetonitrile-pH 3.0 McIlvaine buffer (7 : 3), then cleaned up with an Oasis® MCX mini-cartridge. An external standard calibration curve was used for quantification, after sample purification by the combination of a reverse-phase strong cation exchange mixed mode cartridge for cleanup and a HILIC column for HPLC. The method was validated by performing recovery tests in accordance with Japanese guidelines for the validation of analytical methods for residual agricultural chemicals in food. Recovery ranged from 79.3% to 91.7%, RSDs of repeatability were under 3.3%, and RSDs of within-laboratory reproducibility were under 8.4%. This new method was applied to samples of poultry and egg purehased in Tokyo, but residual amantadine was not detected at all.

  16. Simultaneous determination of metformin and vildagliptin in human plasma by a HILIC-MS/MS method.

    PubMed

    Pontarolo, Roberto; Gimenez, Ana Carolina; de Francisco, Thais Martins Guimarães; Ribeiro, Rômulo Pereira; Pontes, Flávia Lada Degaut; Gasparetto, João Cleverson

    2014-08-15

    The objective of this work was to develop and validate a HILIC-MS/MS method for the simultaneous determination of metformin and vildagliptin in human plasma. Chromatographic separation was achieved using an Atlantis HILIC Silica 150-mm × 2.1-mm, 3-μm particle size column maintained at 40°C. The isocratic mobile phase consisted of 20% water and 80% acetonitrile/water solution 95:5 (v/v), containing both 0.1% formic acid and 3mM ammonium formate. The flow rate was maintained at 400 μL min(-1). Data from validation studies demonstrated that the new method is highly selective, sensitive (limits of detection <1.5 ng mL(-1)) and free of matrix and residual effects. The new method was also precise (RSD<9.0%), accurate (RE<11.2%) and linear (r ≥ 0.99) over the ranges of 5-500 ng mL(-1) for each compound. The developed method was successfully applied to determine metformin and vildagliptin in plasma volunteers who orally received a single dose of metformin (850 mg), vildagliptin (50mg) or drug association (metformin 850 mg+vildagliptin 50mg). The new method can thus also be used as a tool for the clinical monitoring of metformin and vildagliptin.

  17. IPeak: An open source tool to combine results from multiple MS/MS search engines.

    PubMed

    Wen, Bo; Du, Chaoqin; Li, Guilin; Ghali, Fawaz; Jones, Andrew R; Käll, Lukas; Xu, Shaohang; Zhou, Ruo; Ren, Zhe; Feng, Qiang; Xu, Xun; Wang, Jun

    2015-09-01

    Liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) is an important technique for detecting peptides in proteomics studies. Here, we present an open source software tool, termed IPeak, a peptide identification pipeline that is designed to combine the Percolator post-processing algorithm and multi-search strategy to enhance the sensitivity of peptide identifications without compromising accuracy. IPeak provides a graphical user interface (GUI) as well as a command-line interface, which is implemented in JAVA and can work on all three major operating system platforms: Windows, Linux/Unix and OS X. IPeak has been designed to work with the mzIdentML standard from the Proteomics Standards Initiative (PSI) as an input and output, and also been fully integrated into the associated mzidLibrary project, providing access to the overall pipeline, as well as modules for calling Percolator on individual search engine result files. The integration thus enables IPeak (and Percolator) to be used in conjunction with any software packages implementing the mzIdentML data standard. IPeak is freely available and can be downloaded under an Apache 2.0 license at https://code.google.com/p/mzidentml-lib/.

  18. Development and validation of UFLC-MS/MS method for determination of bosentan in rat plasma.

    PubMed

    Atila, Alptug; Ozturk, Murat; Kadioglu, Yucel; Halici, Zekai; Turkan, Didar; Yayla, Muhammed; Un, Harun

    2014-08-01

    A rapid, simple and sensitive UFLC-MS/MS method was developed and validated for the determination of bosentan in rat plasma using etodolac as an internal standard (IS) after liquid-liquid extraction with diethyl ether-chloroform (4:1, v/v). Bosentan and IS were detected using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the transitions m/z 551.90→201.90 and 288.20→172.00, respectively. Chromatographic separation was performed on the inertsil ODS-4 column with a gradient mobile phase, which consisted of 0.1% acetic acid with 5mM ammonium acetate in water for solvent A and 5mM ammonium acetate in acetonitrile-methanol (50:50, v/v) for solvent B at a flow rate of 0.3mL/min. The method was sensitive with 0.5ng/mL as the lower limit of quantitation (LLOQ) and the standard calibration curve for bosentan was linear (r>0.997) over the studied concentration range (0.5-2000ng/mL). The proposed method was fully validated by determining specificity, linearity, LLOQ, precision and accuracy, recovery, matrix effect and stability. The validated method was successfully applied to plasma samples obtained from rats.

  19. MS/MS-based strategies for proteomic profiling of invasive cell structures.

    PubMed

    Havrylov, Serhiy; Park, Morag

    2015-01-01

    Acquired capacity of cancer cells to penetrate through the extracellular matrix of surrounding tissues is a prerequisite for tumour metastatic spread - the main source of cancer-associated mortality. Through combined efforts of many research groups, we are beginning to understand that the ability of cells to invade through the extracellular matrix is a multi-faceted phenomenon supported by variety of specialised protrusive cellular structures, primarily pseudopodia, invadopodia and podosomes. Additionally, secreted extracellular vesicles are being increasingly recognised as important mediators of invasive cell phenotypes and therefore may be considered bona fide invasive cell structures. Dissection of the molecular makings underlying biogenesis and function of all of these structures is crucial to identify novel targets for specific anti-metastatic therapies. Rapid advances and growing accessibility of MS/MS-based protein identification made this family of techniques a suitable and appropriate choice for proteomic profiling of invasive cell structures. In this review, we provide a summary of current progress in the characterisation of protein composition and topology of protein interaction networks of pseudopodia, invadopodia, podosomes and extracellular vesicles, as well as outline challenges and perspectives of the field.

  20. Multi-mycotoxin stable isotope dilution LC-MS/MS method for Fusarium toxins in cereals.

    PubMed

    Habler, Katharina; Rychlik, Michael

    2016-01-01

    A multi-mycotoxin stable isotope dilution LC-MS/MS method was developed for 14 Fusarium toxins including modified mycotoxins in cereals (deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, HT2-toxin, T2-toxin, enniatin B, enniatin B1, enniatin A1, enniatin A, beauvericin, fusarenone X, nivalenol, deoxynivalenol-3-glucoside, and zearalenone). The chromatographic separation of the toxins with particular focus on deoxynivalenol and deoxynivalenol-3-glucoside was achieved using a C18-hydrosphere column. An expedient sample preparation method was developed that uses solid-phase extraction for the purification of trichothecenes combined with zearalenone, enniatins, and beauvericin and provides excellent validation data. Linearity, intra-day precision, inter-day precision, and recoveries were ≥0.9982, 1-6%, 5-12%, and 79-117%, respectively. Method accuracy was verified by analyzing certified reference materials for deoxynivalenol, HT2-toxin, and T2-toxin with deviations below 7%. The results of this method found barley malt samples from 2012, 2013, and 2014 frequently contaminated with high concentrations of enniatin B, deoxynivalenol, and its modified mycotoxin deoxynivalenol-3-glucoside. Samples from 2012 were especially contaminated. Fusarenone X was not detected in any of the analyzed samples.

  1. Quantitation of brinzolamide in dried blood spots by a novel LC-QTOF-MS/MS method.

    PubMed

    Foivas, Anargyros; Malenović, Anđelija; Kostić, Nađa; Božić, Marija; Knežević, Miroslav; Loukas, Yannis L; Dotsikas, Yannis

    2016-02-05

    In the current study, a rapid and sensitive LC-QTOF-MS/MS method for the determination of brinzolamide in dried blood spots (DBS) was developed and validated. This novel sample collection, storage and transfer technique was suitable for analyzing a drug with high distribution into red blood cells and negligible plasma levels. The method included an isocratic mobile phase consisting of methanol and 10mM ammonium formate (90:10, v/v) and detection in positive electrospray mode (ESI+). The flow rate was adjusted to 0.350mL/min yielding retention times of 1.7min for both brinzolamide and internal standard (IS) rabeprazole on a Cyano analytical column, respectively. The validation of the proposed method over the concentration range 0.500-20.0μg/mL was performed in compliance with EMEA and FDA guidelines, assessing all major performance characteristics. Inter- and intra- assay precisions were less than 14%, while inter- and intra- assay accuracies varied from 92.2 to 111%. No matrix effect was observed and the mean brinzolamide extraction recovery was 93.5%. The method was successfully applied to real DBS samples from patients in steady state condition, receiving brinzolamide ophthalmic suspension 1% (w/v) for several months. Initial concentrations were corrected due to hematocrit effect, using image processing algorithm written in Matlab.

  2. Isotope dilution LC/MS/MS for the detection of nerve agent exposure in urine.

    PubMed

    Ciner, Frederic L; McCord, Carla E; Plunkett, Roy W; Martin, Michael F; Croley, Timothy R

    2007-02-01

    Organophosphorus nerve agents (OPNA), chemically related to and derived from organophosphate insecticides, constitute a clear and present threat to both military and civilian targets. Military regimes and terrorist organizations have demonstrated the will and ability to produce mass casualties by dispersing organophosphorus nerve agents, which, in turn could terrorize populations and overwhelm healthcare systems. A high throughput, robust and sensitive analytical protocol has been developed for the quantitation of the urinary metabolites of sarin (GB), soman (GD), VX, Russian VX (RVX) and cyclohexylsarin (GF) utilizing solid phase extraction (SPE) followed by High Performance Liquid Chromatography (HPLC)-isotope dilution tandem mass spectrometry (LC/MS/MS). The method has demonstrated linearity and reproducibility (1-200 ng/mL) for all analytes and has a Limit of Quantitation (LOQ)< or =0.5 ng/mL for all analytes (S/N> or =10/1). The method was validated by performing 20 individual analyses over 10 days by five scientists with all values falling within two standard deviations of the mean.

  3. Method Development and Validation for UHPLC-MS-MS Determination of Hop Prenylflavonoids in Human Serum

    PubMed Central

    Yuan, Yang; Qiu, Xi; Nikolic, Dejan; Dahl, Jeffrey H.; van Breemen, Richard B.

    2013-01-01

    Hops (Humulus lupulus L.) are used in the brewing of beer, and hop extracts containing prenylated compounds such as xanthohumol and 8-prenylnaringenin are under investigation as dietary supplements for cancer chemoprevention and for the management of hot flashes in menopausal women. To facilitate clinical studies of hop safety and efficacy, a selective, sensitive, and fast ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS-MS) method was developed and validated for the simultaneous determination of the hop prenylflavonoids xanthohumol, isoxanthohumol, 6-prenylnaringenin, and 8-prenylnaringenin in human serum. The analytical method requires 300 μL of human serum which is processed using liquid-liquid extraction. UHPLC separation was carried out in 2.5 min with gradient elution using a reversed phase column containing 1.6 μm packing material. Prenylflavonoids were measured using negative ion electrospray mass spectrometry with collision-induced dissociation and selected reaction monitoring. The method was validated and showed good accuracy and precision with a lower limit of quantitation (LLOQ) of 0.50 ng/mL for XN (1.4 nM) and 1.0 ng/mL for 6-PN (2.8 nM), XN and IX (2.9 nM) in serum for each analyte. PMID:23451393

  4. LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang).

    PubMed

    Chua, Lee Suan; Amin, Nor Amaiza Mohd; Neo, Jason Chun Hong; Lee, Ting Hun; Lee, Chew Tin; Sarmidi, Mohamad Roji; Aziz, Ramlan Abdul

    2011-12-15

    A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.

  5. Quantification of Hydrazine in Human Urine by HPLC-MS-MS.

    PubMed

    Isenberg, Samantha L; Carter, Melissa D; Crow, Brian S; Graham, Leigh Ann; Johnson, Darryl; Beninato, Nick; Steele, Kandace; Thomas, Jerry D; Johnson, Rudolph C

    2016-05-01

    Currently used on F-16 fighter jets and some space shuttles, hydrazine could be released at toxic levels to humans as a result of an accidental leakage or spill. Lower-level exposures occur in industrial workers or as a result of the use of some pharmaceuticals. A method was developed for the quantitation of hydrazine in human urine and can be extended by dilution with water to cover at least six orders of magnitude, allowing measurement at all clinically significant levels of potential exposure. Urine samples were processed by isotope dilution, filtered, derivatized and then quantified by HPLC-MS-MS. The analytical response ratio was linearly proportional to the urine concentration of hydrazine from 0.0493 to 12.3 ng/mL, with an average correlation coefficientRof 0.9985. Inter-run accuracy for 21 runs, expressed as percent relative error (% RE), was ≤14%, and the corresponding precision, expressed as percent relative standard deviation (% RSD), was ≤15%. Because this method can provide a quantitative measurement of clinical samples over six orders of magnitude, it can be used to monitor trace amounts of hydrazine exposure as well as industrial and environmental exposure levels.

  6. Simultaneous quantification of ten cytotoxic drugs by a validated LC-ESI-MS/MS method.

    PubMed

    Nussbaumer, Susanne; Fleury-Souverain, Sandrine; Antinori, Paola; Sadeghipour, Farshid; Hochstrasser, Denis F; Bonnabry, Pascal; Veuthey, Jean-Luc; Geiser, Laurent

    2010-12-01

    A liquid chromatography separation with electrospray ionisation and tandem mass spectrometry detection method was developed for the simultaneous quantification of ten commonly handled cytotoxic drugs in a hospital pharmacy. These cytotoxic drugs are cytarabine, gemcitabine, methotrexate, etoposide phosphate, cyclophosphamide, ifosfamide, irinotecan, doxorubicin, epirubicin and vincristine. The chromatographic separation was carried out by RPLC in less than 21 min, applying a gradient elution of water and acetonitrile in the presence of 0.1% formic acid. MS/MS was performed on a triple quadrupole in selected reaction monitoring mode. The analytical method was validated to determine the limit of quantification (LOQ) and quantitative performance: lowest LOQs were between 0.25 and 2 ng mL(-1) for the ten investigated cytotoxic drugs; trueness values (i.e. recovery) were between 85% and 110%, and relative standard deviations for both repeatability and intermediate precision were always inferior to 15%. The multi-compound method was successfully applied for the quality control of pharmaceutical formulations and for analyses of spiked samples on potentially contaminated surfaces.

  7. Development and validation of an HPLC-MS/MS method for the early diagnosis of aspergillosis.

    PubMed

    Cerqueira, Letícia B; de Francisco, Thais M G; Gasparetto, João C; Campos, Francinete R; Pontarolo, Roberto

    2014-01-01

    Invasive aspergillosis is an opportunistic infection that is mainly caused by Aspergillus fumigatus, which is known to produce several secondary metabolites, including gliotoxin, the most abundant metabolite produced during hyphal growth. The diagnosis of invasive aspergillosis is often made late in the infection because of the lack of reliable and feasible diagnostic techniques; therefore, early detection is critical to begin treatment and avoid more serious complications. The present work reports the development and validation of an HPLC-MS/MS method for the detection of gliotoxin in the serum of patients with suspected aspergillosis. Chromatographic separation was achieved using an XBridge C18 column (150 × 2.1 mm id; 5 mm particle size) maintained at 25 °C with the corresponding guard column (XBridge C18, 10 × 2.1 mm id, 5 mm particle size). The mobile phase was composed of a gradient of water and acetonitrile/water (95:5 v/v), both containing 1 mM ammonium formate with a flow rate of 0.45 mL min(-1). Data from the validation studies demonstrate that this new method is highly sensitive, selective, linear, precise, accurate and free from matrix interference. The developed method was successfully applied to samples from patients suspected of having aspergillosis. Therefore, the developed method has considerable potential as a diagnostic technique for aspergillosis.

  8. Dried haematic microsamples and LC-MS/MS for the analysis of natural and synthetic cannabinoids.

    PubMed

    Protti, Michele; Rudge, James; Sberna, Angelo Eliseo; Gerra, Gilberto; Mercolini, Laura

    2017-02-15

    Synthetic cannabinoids are new psychoactive substances (NPS) with similar effects when compared to natural ones found in Cannabis derivatives. They have rapidly integrated into the illicit market, often sold as alternatives under international control. The need to identify and quantify an unprecedented and growing number of new compounds represents a unique challenge for toxicological, forensic and anti-doping analysis. Dried blood spots have been used within the bioanalytical framework in place of plasma or serum, in order to reduce invasiveness, lower sample size, simplify handling, storage and shipping of samples and to facilitate home-based and on-field applications. However, DBS implementation has been limited mainly by concerns related to haematocrit effect on method accuracy. Volumetric absorptive microsampling (VAMS™), a second generation dried miniaturized sampling technology, has been developed just in order to eliminate haematocrit effect, thus providing accurate sampling but still granting feasible sample processing. An original LC-MS/MS method was herein developed and validated for the analysis of THC and its 2 main metabolites, together with 10 representative synthetic cannabinoids in both DBS and VAMS dried microsamples. The ultimate goal of this work is to provide highly innovative DBS and VAMS analytical protocols, whose performances were extensively optimized and compared, in order to provide effective and alternative tools that can be applied for natural and synthetic cannabinoid determination, in place of classical analytical strategies.

  9. Determination of colistin in human plasma, urine and other biological samples using LC-MS/MS.

    PubMed

    Ma, Zheng; Wang, Jiping; Gerber, Jacobus P; Milne, Robert W

    2008-02-01

    A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed to quantify colistin in human plasma and urine, and perfusate and urine from the isolated perfused rat kidney (IPK). Solid phase extraction (SPE) preceded chromatography on a Synergi Fusion-RP column with a mobile phase of acetonitrile, water and acetic acid (80/19/1) at 0.2mL/min. Ions were generated using electrospray ionization and detected in the positive-ion mode. Multiple reaction monitoring was performed using precursor-product ion combinations. Calibration curves were linear from 0.028microg/mL (human plasma, IPK perfusate and urine)/0.056microg/mL (human urine) to 1.78microg/mL (all four media) for colistin A sulfate; corresponding values for colistin B sulfate were 0.016/0.032 to 1.01microg/mL. Accuracy and precision were within 10%. The LLOQ for colistin A sulfate was 0.028microg/mL in human plasma, IPK perfusate and urine and 0.056microg/mL in human urine; corresponding values for colistin B sulfate were 0.016 and 0.032microg/mL. The low sample volume, short analysis time and low LLOQ are ideal for pre-clinical and human pharmacokinetic studies of colistin.

  10. Bioanalytical Method for Carbocisteine in Human Plasma by Using LC-MS/MS: A Pharmacokinetic Application.

    PubMed

    Dhanure, Shivanand; Savalia, Atulkumar; More, Pravinkumar; Shirode, Prashant; Kapse, Kailas; Shah, Virag

    2014-01-01

    A simple, sensitive, and selective LC-MS/MS method was developed and validated for the quantification of carbocisteine in human plasma. Rosiglitazone was used as the internal standard and heparin was used as the anticoagulant. The chromatographic separation was performed by using the Waters Symmetry Shield RP 8, 150 × 3.9 mm, 5 μ column at 40°C with a mobile phase consisting of a mixture of methanol and 0.5% formic acid solution in a 40:60 proportion. The flow rate was 500 μl/min along with a 5 μl injection volume. Protein precipitation was used as the extraction method. Mass spectrometric data were detected in positive ion mode. The MRM mode of the ions for carbocisteine was 180.0 > 89.0 and for rosiglitazone it was 238.1 > 135.1. The method was validated in the concentration curve range of 50.000 ng/mL to 6000.000 ng/mL. The retention times of carbocisteine and the internal standard rosiglitazone were approximately 2.20 and 3.01 min, respectively. The overall run time was 4.50 min. This method was found suitable to analyze human plasma samples for the application in pharmacokinetic and BA/BE studies.

  11. Bioanalytical Method for Carbocisteine in Human Plasma by Using LC-MS/MS: A Pharmacokinetic Application

    PubMed Central

    Dhanure, Shivanand; Savalia, Atulkumar; More, Pravinkumar; Shirode, Prashant; Kapse, Kailas; Shah, Virag

    2014-01-01

    Abstract A simple, sensitive, and selective LC-MS/MS method was developed and validated for the quantification of carbocisteine in human plasma. Rosiglitazone was used as the internal standard and heparin was used as the anticoagulant. The chromatographic separation was performed by using the Waters Symmetry Shield RP 8, 150 × 3.9 mm, 5 μ column at 40°C with a mobile phase consisting of a mixture of methanol and 0.5% formic acid solution in a 40:60 proportion. The flow rate was 500 μl/min along with a 5 μl injection volume. Protein precipitation was used as the extraction method. Mass spectrometric data were detected in positive ion mode. The MRM mode of the ions for carbocisteine was 180.0 > 89.0 and for rosiglitazone it was 238.1 > 135.1. The method was validated in the concentration curve range of 50.000 ng/mL to 6000.000 ng/mL. The retention times of carbocisteine and the internal standard rosiglitazone were approximately 2.20 and 3.01 min, respectively. The overall run time was 4.50 min. This method was found suitable to analyze human plasma samples for the application in pharmacokinetic and BA/BE studies. PMID:26171322

  12. Antioxidant capacity and phenolic compounds of Lonicerae macranthoides by HPLC-DAD-QTOF-MS/MS.

    PubMed

    Hu, Xin; Chen, Lin; Shi, Shuyun; Cai, Ping; Liang, Xuejuan; Zhang, Shuihan

    2016-05-30

    Lonicerae macranthoides with strong antioxidant activity is commonly used in traditional Chinese medicine and folk tea/beverage. However, detailed information about its antioxidant activity and bioactive compounds is limited. Then at first, we comparatively evaluated total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities of water extract, petroleum ether, ethyl acetate and n-butanol fractions of L. macranthoides. Ethyl acetate fraction exhibited the highest level of TPC (207.38 mg GAE/g DW), TFC (53.06 mg RE/g DW) and the best DPPH scavenge activity and reducing power. n-Butanol fraction showed the best ABTS(+) and O2(-) scavenging activities. Interestingly, water extract, ethyl acetate and n-butanol fractions showed stronger antioxidant activities than positive control, butylated hydroxytoluene (BHT). After that, thirty-one antioxidant phenolic compounds, including twenty-two phenolic acids and nine flavonoids, were screened by DPPH-HPLC experiment and then identified using HPLC-DAD-QTOF-MS/MS. It is noted that twenty-one compounds (1, 3-4, 6-17, 19, 23, 26, 28-29, and 31), as far as was known, were discovered from L. macranthoide for the first time, and eleven of them (3-4, 10-17, and 23) were reported in Lonicera species for the first time. Results indicated that L. macranthoides could serve as promising source of rich antioxidants in foods, beverages and medicines for health promotion.

  13. [Simultaneous determination of 3 phenolic acids in Usnea by HPLC-ESI-MS/MS].

    PubMed

    Ma, Ying-hua; Tian, Ting-tingi; Xie, Wei-wei; Jin, Yi-ran; Xu, Hui-jun; Zhang, Lan-tong; Du, Ying-feng

    2015-12-01

    A quick HPLC-ESI-MS/MS method was established for simultaneous determination of three chemical compositions in Usnea, including usnic acid, diffractaic acid, and ramalic acid. The separation was performed on a chromatographic column of Agilent ZORBAX SB-C, (4.6 mm x 250 mm, 5 µm), and the mobile phase was methanol (0.05% formic acid)-0.05% formic acid solution (4 mmol ammonium acetate), with an isocratic elution at a flow rate of 0.8 ml · min⁻¹. Multiple reaction monitoring scanning mode (MRM) was performed combined with the ion switching technology in positive and negative ion switching mode to apply for the quantitative determination. The calibration curves for the above three compounds were linear in corresponding injection amount. Their average recoveries were 95.0%-105.1%, with RSDs of 1.1%-5.2%. The method was simple, rapid, accurate with high repeatability, which could provide a reference for overcalling evaluation the quality of Usnea.

  14. UHPLC/ESI-MS/MS Determination of 187 Pesticides in Wine.

    PubMed

    Wang, Jian; Cheung, Wendy

    2016-01-01

    This paper presents an ultra HPLC/electrospray ionization-tandem MS method to determine pesticides in wine. We adopted the quick, easy, cheap, effective, rugged, and safe (QuEChERs) method for extraction and used core-shell column to achieve ultra-HPLC to develop and validate a simple and fast method to analyze 187 pesticide residues in red and white wine samples. Pesticide residues were extracted from wine samples using QuEChERS. Ultra HPLC/electrospray ionization-tandem MS quantification was achieved using matrix-matched standard calibration curves with isotopically labeled standards or a chemical analogue as internal standards with an analytical range from 5.0 to 500.0 μg/L. The method performance characteristics that included overall recovery, intermediate precision, and measurement uncertainty were evaluated according to a nested experimental design. Generally, 98.4% (in red wine) and 96.8% (in white wine) of the pesticides had recoveries between 71 and 120%; 98.9% (in red wine) and 99.5% (in white wine) of the pesticides had the intermediate precision ≤20%; and 99.5% (in red wine) and 98.4% (in white wine) of the pesticides had measurement uncertainty ≤50%.

  15. Simultaneous determination of sweeteners in beverages by LC-MS/MS.

    PubMed

    Sakai, Hiroaki; Yamashita, Azusa; Tamura, Masayoshi; Uyama, Atsuo; Mochizuki, Naoki

    2015-01-01

    A new method was established for the simultaneous determination of 10 sweeteners and a degradation product in beverages by using LC-MS/MS. An ACQUITY UPLC BEH C18 (2.1 × 100 mm, 1.7 μm) was used as the LC column and 0.1% each of aqueous formic acid and formic acid in acetonitrile were used as the mobile phase. A simple and rapid determination of sweeteners was possible by diluting with a solvent, and in the case of some samples containing a large amount of foreign matter, after pre-treatment by diluting with solvent and clean-up of the sample using an Oasis HLB cartridge. All the validation results were satisfactory. As the regulations and standards for sweeteners vary from country to country, a field survey of 58 beverages marketed in Japan was performed using the present method. No issues concerning the labelling or food sanitation law were found in the tested samples.

  16. A quick LC-MS-MS method for the determination of flunixin in bovine muscle.

    PubMed

    Lugoboni, B; Barbarossa, A; Gazzotti, T; Zironi, E; Farabegoli, F; Pagliuca, G

    2014-03-01

    A simple, fast and cost-effective liquid chromatographic/tandem mass spectrometry (LC-MS-MS) method for the quantitative determination of flunixin (FLU) in bovine muscle was developed and validated. The sample preparation procedure involved an extraction with acetonitrile, followed by evaporation and reconstitution. Chromatographic separation was achieved on a reverse-phase column under programmed conditions. FLU detection was performed with positive electrospray ionization in selected reaction monitoringmode, monitoring one precursor and two products ions. For quantification purposes, FLU-d3 was used as an internal standard. The matrix effect on the analysis of FLU in bovine muscle was evaluated by comparison between calibration curves prepared with standard solution and in blank matrix extracts. The equivalent responses obtained confirmed the absence of signal suppression or/and enhancement. The method was extensively validated according to the parameters requested by European Commission Decision 2002/657/EC in terms of specificity, limit of detection, linearity, trueness, precision, decision limit (CCα) and detection capability (CCβ). FLU stability was also investigated in matrix and in sample extracts at different times and storage conditions.

  17. Development and validation of a LC-MS/MS method to determine sulforaphane in honey.

    PubMed

    Ares, Ana M; Valverde, Silvia; Bernal, José L; Nozal, María J; Bernal, José

    2015-08-15

    A new method was developed to determine sulforaphane (SFN) in honey using liquid chromatography tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). An efficient extraction procedure was proposed (average analyte recoveries were between 92% and 99%); this involved a solid phase extraction (SPE) with a polymeric sorbent. Chromatography was performed on a Synergi™ Hydro analytical column with a mobile phase of 0.02 M ammonium formate in water and acetonitrile, at a flow rate of 0.5 mL/min. The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, carry-over effect, reinjection reproducibility, precision and accuracy. The LOD and LOQ values were below 0.8 μg/kg and 2.6 μg/kg, respectively. The proposed method was applied to analyze SFN in honey from different botanical origins (rosemary, multifloral, orange blossom and heather), and SFN was detected at trace levels in some of the honey samples examined.

  18. Exposure assessment approach through mycotoxin/creatinine ratio evaluation in urine by GC-MS/MS.

    PubMed

    Rodríguez-Carrasco, Yelko; Moltó, Juan Carlos; Mañes, Jordi; Berrada, Houda

    2014-10-01

    In this pilot survey human urine samples were analyzed for presence of 15 mycotoxins and some of their metabolites using a novel urinary multi-mycotoxin GC-MS/MS method following salting-out liquid-liquid extraction. Fifty-four urine samples from children and adults residents in Valencia were analyzed for presence of urinary mycotoxin and expressed in gram of creatinine. Three out of 15 mycotoxins were detected namely, HT-2 toxin, nivalenol and deoxynivalenol (DON). 37 samples showed quantifiable values of mycotoxins. Co-occurrence of these contaminants was also observed in 20.4% of assayed samples. DON was the most frequently detected mycotoxin (68.5%) with mean levels of 23.3 μg/g creatinine (range: 2.8-69.1 μg/g creatinine). The levels of urinary DON were used to carry out an exposure assessment approach. 8.1% of total subjects were estimated to exceed the DON provisional maximum tolerable daily intake (PMTDI) (1 μg/kg b.w.). Two out of 9 exposed children exceeded the DON PMTDI thus, making them the most exposed based on the urinary results.

  19. Characterization of the Human Pancreatic Islet Proteome by Two-Dimensional LC/MS/MS

    SciTech Connect

    Metz, Thomas O.; Jacobs, Jon M.; Gritsenko, Marina A.; Fontes, Ghislaine; Qian, Weijun; Camp, David G.; Poitout, Vincent J.; Smith, Richard D.

    2006-12-01

    Research to elucidate the pathogenesis of type 1 diabetes mellitus has traditionally focused on the genetic and immunological factors associated with the disease, and, until recently, has not considered the target cell. While there have been reports detailing proteomic analyses of established islet cell lines or isolated rodent islets, the information gained is not always easily extrapolated to humans. Therefore, extensive characterization of the human islet proteome could result in better understanding of islet biology and lead to more effective treatment strategies. We have applied a two-dimensional LC-MS/MS-based analysis to the characterization of the human islet proteome, resulting in the detection of 29,021 unique peptides corresponding to 4,925 proteins. As expected, major islet hormones (insulin, glucagon, somatostatin), beta-cell enriched secretory products (IAPP), ion channels (K-ATP channel), and transcription factors (PDX-1, Nkx 6.1, HNF-1 beta) were detected. In addition, significant proteome coverage of metabolic enzymes and cellular pathways was obtained, including the insulin signaling cascade and the MAP kinase, NF-κβ, and JAK/STAT pathways. This work represents the most extensive characterization of the human islet proteome to date and provides a peptide reference library that may be utilized in future studies of islet biology and type 1 diabetes.

  20. Using SPE-LC-ESI-MS/MS Analysis to Assess Disperse Dyes in Environmental Water Samples.

    PubMed

    Zocolo, Guilherme Julião; Pilon dos Santos, Glauco; Vendemiatti, Josiane; Vacchi, Francine Inforçato; Umbuzeiro, Gisela de Aragão; Zanoni, Maria Valnice Boldrin

    2015-09-01

    We have optimized an SPE-LC-ESI-MS/MS method and used it to monitor disperse azo dyes in environmental aquatic samples. Calibration curves constructed for nine disperse dyes-Red 1, Violet 93, Blue 373, Orange 1, Orange 3, Orange 25, Yellow 3, Yellow 7 and Red 13-in aqueous solution presented good linearity between 2.0 and 100.0 ng mL(-1). The method provided limits of detection and quantification around 2.0 and 8.0 ng L(-1), respectively. For dyes at concentrations of 25.0 ng mL(-1), the intra- and interday analyses afforded relative standard deviation lower than 6 and 13%, respectively. The recovery values obtained for each target analyte in Milli-Q water, receiving waters and treated water samples spiked with the nine studied dyes at concentrations of 8.0, 25.0 and 50.0 ng L(-1) (n = 3) gave average recoveries greater than 70%, with RSD <20%. Statistical evaluation aided method validation. The validated method proved to be useful for analysis of organic extracts from effluents and receiving water samples after an SPE extraction step. More specifically, the method enabled detection of the dyes Disperse Red 1, Disperse Blue 373 and Disperse Violet 93 at concentrations ranging from 84 to 3452 ng L(-1) in the treated effluent (TE), affluent and points collected upstream and downstream of the drinking water treatment plant of a textile dye industry in Brazil.

  1. HPLC-MS/MS investigation of biochemical markers for the disclosure of erythropoietin abuse in sports

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    The polypeptide hormone erythropoietin (EPO), which is a forbidden doping drug, was determined by high-performance liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS). The hypothesis about the influence of EPO on the asymmetric dimethylarginine (ADMA)-dimethylargininedime-thylaminohydrolase (DDAH)-NO-synthase system was verified. Changes in this system can serve as indirect biochemical markers of the presence of the forbidden EPO drug in the organism. In the test group, the concentrations of biochemical markers varied from 10 to 40 μg/ml for ADMA and symmetrical DMA (SDMA) and from 0.5 to 10 μg/ml for arginine and citrulline. A single intravenous administration of r-HuEPO (Epocrin, 2000 ME/day) for two volunteers reliably increased ADMA, SDMA, arginine, and citrulline concentrations to 40-270 μg/ml, 40-240μg/ml, 10-60 μg/ml, and 12-140 μg/ml, respectively, with respect to the reference values. The simultaneous increase in arginine, methylarginines, and citrulline contents could be an indirect marker of EPO abuse. The method is recommended for fast screening analysis.

  2. Carotenoid composition of jackfruit (Artocarpus heterophyllus), determined by HPLC-PDA-MS/MS.

    PubMed

    de Faria, A F; de Rosso, V V; Mercadante, A Z

    2009-06-01

    Carotenoids are pigments responsible for the yellow-reddish color of many foods and are related to important functions and physiological actions, preventing several chronic-degenerative diseases. The objective of this study was to confirm the carotenoid composition of jackfruit by high-performance liquid chromatography connected to photodiode array and mass spectrometry detectors (HPLC-PDA-MS/MS). The main carotenoids were all-trans-lutein (24-44%), all-trans-beta-carotene (24-30%), all-trans-neoxanthin (4-19%), 9-cis-neoxanthin (4-9%) and 9-cis-violaxanthin (4-10%). Either qualitative or quantitative differences, mainly related to the lutein proportion, were found among three batches of jackfruit. Since the fruits from batch A showed significantly lower contents for almost all carotenoids, it also had the lowest total carotenoid content (34.1 microg/100 g) and provitamin A value, whereas the total carotenoid ranged from 129.0 to 150.3 microg/100 g in the other batches. The provitamin A values from batches B and C were 3.3 and 4.3 microg RAE/100 g, respectively. The carotenoid composition of jackfruit was successfully determined, where 14 of the 18 identified carotenoids were reported for first time. Differences among batches may be due to genetic and/or agricultural factors.

  3. Enantioselective analysis of etodolac in human plasma by LC-MS/MS: Application to clinical pharmacokinetics.

    PubMed

    de Miranda Silva, Carolina; Rocha, Adriana; Tozatto, Eduardo; da Silva, Lucienir Maria; Donadi, Eduardo Antônio; Lanchote, Vera Lucia

    2016-02-20

    Etodolac is a non-steroidal anti-inflammatory drug with preferential inhibition of cyclooxigenase-2 and is widely used in the management of pain in patients with inflammatory arthritis. Etodolac is available as a racemic mixture of (-)-(R)-Etodolac and (+)-(S)-Etodolac; cyclooxigenases inhibition is attributed to (+)-(S)-Etodolac. According to our knowledge, this is the first method for determination of etodolac enantiomers in plasma using LC-MS/MS. Plasma extraction were performed with 25μL of plasma and 1mL of n-hexane:ethyl acetate (95:5); racemic ibuprofen was used as internal standard. Resolution of enantiomers were performed in a Chiralcel(®)OD-H column; deprotonated [M-H](-) and their respective ion products were monitored at transitions of 286>242 for etodolac enantiomers and 205>161 for ibuprofen. The quantitation limit was 3.2ng/mL for both enantiomers in plasma. The method was applied to study the pharmacokinetics of etodolac enantiomers after the administration of a 300 and 400mg dose of racemic drug to a healthy volunteer. Analysis of plasma samples showed higher plasma concentration of (-)-(R)-Etodolacfor both doses (300mg dose: AUC(0-∞)49.80 versus 4.55ugh/mL;400mg dose: AUC(0-∞) 63.90 versus 6.00ugh/mL) with an (R)-(+)/(S)-(-) ratio of approximately 11.

  4. Multi-mycotoxin stable isotope dilution LC-MS/MS method for Fusarium toxins in beer.

    PubMed

    Habler, Katharina; Gotthardt, Marina; Schüler, Jan; Rychlik, Michael

    2017-03-01

    A stable isotope dilution LC-MS/MS multi-mycotoxin method was developed for 12 different Fusarium toxins including modified mycotoxins in beer (deoxynivalenol-3-glucoside, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyl-deoxynivalenol, HT2-toxin, T2-toxin, enniatin B, B1, A1, A, beauvericin and zearalenone). As sample preparation and purification of beer a combined solid phase extraction for trichothecenes, enniatins, beauvericin and zearalenone was firstly developed. The validation of the new method gave satisfying results: intra-day and inter-day precision and recoveries were 1-5%, 2-8% and 72-117%, respectively. In total, 61 different organic and conventional beer samples from Germany and all over the world were analyzed by using the newly developed multi-mycotoxin method. In summary, deoxynivalenol, deoxynivalenol-3-glucoside, 3-acetyldeoxynivaleneol and enniatin B were quantified in rather low contents in the investigated beer samples. None of the other monitored Fusarium toxins like 15-acetyldeoxynivalenol, HT2- and T2-toxin, zearalenone, enniatin B1, A1, A or beauvericin were detectable.

  5. Detection of non-sterol isoprenoids by HPLC-MS/MS

    PubMed Central

    Henneman, Linda; van Cruchten, Arno G.; Denis, Simone W.; Amolins, Michael W.; Placzek, Andrew T.; Gibbs, Richard A.; Kulik, Willem; Waterham, Hans R.

    2012-01-01

    Isoprenoids constitute an important class of biomolecules that participate in many different cellular processes. Most available detection methods only allow the identification of one or two specific non-sterol isoprenoid intermediates following radioactive or fluorescent labeling. We here report a rapid, non-radioactive and sensitive procedure for the simultaneous detection and quantification of the 8 main non-sterol intermediates of the isoprenoid biosynthesis pathway by means of tandem mass spectrometry. Intermediates were analyzed by HPLC-MS/MS in the multiple reaction monitoring mode using a silica-based C18 HPLC column. For quantification, their stable-isotope-labeled analogues were used as internal standards. HepG2 cells were used to validate the method. Mevalonate, phosphomevalonate and the 6 subsequent isoprenoid-pyrophosphates were readily determined with detection limits ranging from 0.03 to 1.0 μmol/L. The intra- and interassay variations for HepG2 cell homogenates supplemented with isoprenoid intermediates were 3.6–10.9% and 4.4–11.9%, respectively. Under normal culturing conditions, isoprenoid intermediates in HepG2 cells were below detection limits. However, incubation of the cells with pamidronate, an inhibitor of farnesyl pyrophosphate synthase, resulted in increased levels of MVA, IPP/DMAPP and GPP. This method will be suitable to measure profiles of isoprenoid intermediates in cells with compromised isoprenoid biosynthesis, and to determine the specificity of potential inhibitors of the pathway. PMID:18782552

  6. UHPLC-MS/MS based target profiling of stress-induced phytohormones.

    PubMed

    Floková, Kristýna; Tarkowská, Danuše; Miersch, Otto; Strnad, Miroslav; Wasternack, Claus; Novák, Ondřej

    2014-09-01

    Stress-induced changes in phytohormone metabolite profiles have rapid effects on plant metabolic activity and growth. The jasmonates (JAs) are a group of fatty acid-derived stress response regulators with roles in numerous developmental processes. To elucidate their dual regulatory effects, which overlap with those of other important defence-signalling plant hormones such as salicylic acid (SA), abscisic acid (ABA) and indole-3-acetic acid (IAA), we have developed a highly efficient single-step clean-up procedure for their enrichment from complex plant matrices that enables their sensitive quantitative analysis using hyphenated mass spectrometry technique. The rapid extraction of minute quantities of plant material (less than 20mg fresh weight, FW) into cold 10% methanol followed by one-step reversed-phase polymer-based solid phase extraction significantly reduced matrix effects and increased the recovery of labile JA analytes. This extraction and purification protocol was paired with a highly sensitive and validated ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method and used to simultaneously profile sixteen stress-induced phytohormones in minute plant material samples, including endogenous JA, several of its biosynthetic precursors and derivatives, as well as SA, ABA and IAA.

  7. Pharmacokinetics, tissue distribution, and plasma protein binding study of chicoric acid by HPLC-MS/MS.

    PubMed

    Wang, Yutang; Xie, Guo; Liu, Qian; Duan, Xiang; Liu, Zhigang; Liu, Xuebo

    2016-09-15

    Chicoric acid is a major active constituent of Echinacea purpurea and has a variety of biological functions. In this study, a liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) approach was developed and validated for the determination of chicoric acid in rat plasma and various tissues using ferulic acid as an internal standard (IS). This method was successfully applied to pharmacokinetics, tissue distribution, and plasma protein binding (PPB) study of chicoric acid in Sprague-Dawley (SD) rats dosed with 50mg/kg by gastric gavage. The pharmacokinetic parameters were determined and showed a half-life (t1/2) of 4.53±1.44h, an apparent volume of mean residual time (MRT) of 18.58±4.43h, and an area under the curve (AUC) of 26.14 mghL(-1). The tissue distribution of chicoric acid in rats after gavage administration showed a decreasing tendency in different tissues (liver>lung>kidney>heart>spleen>brain). The PPB rates in rat plasma, human plasma, and bovine serum albumin were 98.3, 96.9, and 96.6%, respectively. These results provide insight for the further pharmacological investigation of chicoric acid.

  8. A rapid and sensitive technique for assessing exposure to VX via GC-MS-MS analysis.

    PubMed

    McGuire, Jeffrey M; Byers, Christopher E; Hulet, Stanley W; Jakubowski, Edward M; Thomson, Sandra A

    2008-01-01

    A rapid and sensitive method for the determination of the chemical warfare agent VX in plasma taken from Göttingen minipigs has been developed using isotope-dilution gas chromatography-tandem mass spectrometry (GC-MS-MS). Chromatographic separation was achieved on a 5% diphenyl/95% dimethyl polysiloxane capillary column with a total run time of about 11 min. The analyte was detected using ammonia chemical ionization in the multiple reaction monitoring mode, following a simple extraction with 10% 2-propanol in hexane. A good linear relationship was obtained in the quantitative concentration range of 10 ng/mL to 1000 ng/mL (r(2) = 0.9998) with an average slope of 1.275 +/- 0.037 (n = 7), and an absolute detection limit of 0.4 pg on column. The average recovery for VX was 95% in saline in the concentration range of 50-100 ng/mL. The method was successfully applied to the analysis of VX in minipig plasma in a preliminary toxicokinetic study.

  9. Stability-Indicating Method and LC-MS-MS Characterization of Forced Degradation Products of Sofosbuvir.

    PubMed

    Nebsen, M; Elzanfaly, Eman S

    2016-07-19

    Sofosbuvir is a novel direct acting antiviral agent against hepatitis C virus. In the present work, a rapid, specific and reproducible isocratic reversed phase high performance liquid chromatography (RP-HPLC) method has been developed and validated for the determination of sofosbuvir in the presence of its stressed degradation products. Sobosbuvir was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per international conference on harmonization (ICH) conditions. The drug showed degradation under oxidative, photolysis, acid and base hydrolysis stress conditions. However, it was stable under thermal and neutral hydrolysis stress conditions. Chromatographic separation of the drug from its degradation products was performed on Inertsil ODS-3 C18 (250 mm × 4.6 mm i.d., 5 µm) column using a green mobile phase of methanol:water 70:30 (v/v). The degradation products were characterized by LC-MS-MS and the fragmentation pathways were proposed. The developed method was validated as per ICH guidelines. No previous method was reported regarding the degradation behavior of sofosbuvir.

  10. Development and validation of an HPLC–MS/MS method to determine clopidogrel in human plasma

    PubMed Central

    Liu, Gangyi; Dong, Chunxia; Shen, Weiwei; Lu, Xiaopei; Zhang, Mengqi; Gui, Yuzhou; Zhou, Qinyi; Yu, Chen

    2015-01-01

    A quantitative method for clopidogrel using online-SPE tandem LC–MS/MS was developed and fully validated according to the well-established FDA guidelines. The method achieves adequate sensitivity for pharmacokinetic studies, with lower limit of quantifications (LLOQs) as low as 10 pg/mL. Chromatographic separations were performed on reversed phase columns Kromasil Eternity-2.5-C18-UHPLC for both methods. Positive electrospray ionization in multiple reaction monitoring (MRM) mode was employed for signal detection and a deuterated analogue (clopidogrel-d4) was used as internal standard (IS). Adjustments in sample preparation, including introduction of an online-SPE system proved to be the most effective method to solve the analyte back-conversion in clinical samples. Pooled clinical samples (two levels) were prepared and successfully used as real-sample quality control (QC) in the validation of back-conversion testing under different conditions. The result showed that the real samples were stable in room temperature for 24 h. Linearity, precision, extraction recovery, matrix effect on spiked QC samples and stability tests on both spiked QCs and real sample QCs stored in different conditions met the acceptance criteria. This online-SPE method was successfully applied to a bioequivalence study of 75 mg single dose clopidogrel tablets in 48 healthy male subjects. PMID:26904399

  11. UHPLC-MS/MS quantification of buprenorphine, norbuprenorphine, methadone, and glucuronide conjugates in umbilical cord plasma.

    PubMed

    Kyle, Amy Redmond; Carmical, Jennifer; Shah, Darshan; Pryor, Jason; Brown, Stacy

    2015-10-01

    Opioid use during pregnancy can result in the newborn being physically dependent on the substance, thus experiencing drug withdrawal, termed neonatal abstinence syndrome (NAS). Buprenorphine and methadone are two drugs used to treat opioid withdrawal and are approved for use in pregnancy. Quantification of these compounds in umbilical cord plasma would help assess in utero exposure of neonates in cases of buprenorphine or methadone use during pregnancy. An LC-MS/MS method using solid-phase extraction sample preparation was developed and validated for the simultaneous quantification of methadone, buprenorphine, norbuprenorphine, and glucuronide metabolites in umbilical cord plasma. The average accuracy (percentage error) and precision (relative standard deviation) were <15% for each validated concentration. Our data establishes a 2 week maximum freezer storage window in order to achieve the most accurate cord plasma concentrations of these analytes. Additionally, we found that the umbilical cord tissue analysis was less sensitive compared with analysis with umbilical cord blood plasma, indicating that this may be a more appropriate matrix for determination of buprenorphine and metabolite concentrations. This method was successfully applied to the analysis of cord blood from women with known buprenorphine or methadone use during pregnancy.

  12. Characterization of fast-decaying PET radiotracers solely through LC-MS/MS of constituent radioactive and carrier isotopologues

    PubMed Central

    2013-01-01

    Background The characterization of fast-decaying radiotracers that are labeled with carbon-11 (t1/2 = 20.38 min), including critical measurement of specific radioactivity (activity per mole at a specific time) before release for use in positron-emission tomography (PET), has relied heavily on chromatographic plus radiometric measurements, each of which may be vulnerable to significant errors. Thus, we aimed to develop a mass-specific detection method using sensitive liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) for identifying 11C-labeled tracers and for verifying their specific radioactivities. Methods The LC-MS/MS was tuned and set up with methods to generate and measure the product ions specific for carbon-11 species and M + 1 carrier (predominantly the carbon-13 isotopologue) in four 11C-labeled tracers. These radiotracers were synthesized and then analyzed before extensive carbon-11 decay. The peak areas of carbon-11 species and M + 1 carrier from the LC-MS/MS measurement and the calculated abundances of carbon-12 carrier and M + 1 radioactive species gave the mole fraction of carbon-11 species in each sample. This value upon multiplication with the theoretical specific radioactivity of carbon-11 gave the specific radioactivity of the radiotracer. Results LC-MS/MS of each 11C-labeled tracer generated the product ion peaks for carbon-11 species and M + 1 carrier at the expected LC retention time. The intensity of the radioactive peak diminished as time elapsed and was undetectable after six half-lives of carbon-11. Measurements of radiotracer-specific radioactivity determined solely by LC-MS/MS at timed intervals gave a half-life for carbon-11 (20.43 min) in excellent agreement with the value obtained radiometrically. Additionally, the LC-MS/MS measurement gave specific radioactivity values (83 to 505 GBq/μmol) in good agreement with those from conventional radiometric methods. Conclusions 11C-Labeled tracers were

  13. Carcinogenic liver fluke Opisthorchis viverrini oxysterols detected by LC-MS/MS survey of soluble fraction parasite extract.

    PubMed

    Vale, Nuno; Gouveia, Maria João; Botelho, Mónica; Sripa, Banchob; Suttiprapa, Sutas; Rinaldi, Gabriel; Gomes, Paula; Brindley, Paul J; Correia da Costa, José Manuel

    2013-12-01

    Liquid chromatography in tandem mass spectrometry (LC-MS/MS) has emerged as an informative tool to investigate oxysterols (oxidized derivatives of cholesterol) in helminth parasite associated cancers. Here, we used LC-MS/MS to investigate in soluble extracts of the adult developmental stage of Opisthorchis viverrini from experimentally infected hamsters. Using comparisons with known bile acids and the metabolites of estrogens, the LC-MS data indicated the existence of novel oxysterol derivatives in O. viverrini. Most of these derivatives were ramified at C-17, in similar fashion to bile acids and their conjugated salts. Several were compatible with the presence of an estrogen core, and/or hydroxylation of the steroid aromatic ring A, hydroxylation of both C-2 and C-3 of the steroid ring and further oxidation into an estradiol-2,3-quinone.

  14. Joint GC-MS and LC-MS platforms for comprehensive plant metabolomics: repeatability and sample pre-treatment.

    PubMed

    t'Kindt, Ruben; Morreel, Kris; Deforce, Dieter; Boerjan, Wout; Van Bocxlaer, Jan

    2009-11-01

    Metabolomics nowadays mostly comprises the application of both LC-MS and GC-MS based approaches. Here we investigate different extraction set-ups for these two established analytical platforms in the field of plant metabolomics. Six extraction approaches for Arabidopsis thaliana leaves, varying in extraction solvent composition, extraction temperature and order of solvent addition within the extraction sequence, were analyzed on the two platforms. Our aim was to establish the most suitable analysis protocol, practicable for both LC-MS and GC-MS analysis, in order to obtain as extensive as possible metabolome coverage. One single sample preparation procedure would save time and valuable sample while still offering the complementary datasets generated by GC-MS and LC-MS. All extraction approaches were evaluated based on the following criteria: number of detected m/z-retention time pairs, heat maps of the detected peaks, and residual enzymatic activity of invertase and phosphatase in the plant leaf extracts. Unsupervised principal component analysis (PCA) was used to evaluate grouping trends between the different extraction approaches. Quality controls, a blend of aliquots of the different extracts, were used to establish a paired evaluation of the repeatability performance of the GC-MS and LC-MS analysis. We conclude that the use of chloroform in the extraction solvent is counterproductive in an untargeted LC-MS metabolomics approach as is heating. Below room temperature (instead of heated) extraction does not significantly degrade GC-MS performance but one should be more cautious with respect to residual enzymatic activity in the plant extract.

  15. The potential use of complex derivatization procedures in comprehensive HPLC-MS/MS detection of anabolic steroids.

    PubMed

    Baranov, Pavel A; Appolonova, Svetlana A; Rodchenkov, Grigory M

    2010-10-01

    The use of two separate derivatization procedures with the formation of oxime (hydroxyl ammonium pretreatment) and picolinoyl (mixed anhydride method) derivates of anabolic steroids following HPLC-MS/MS analysis was proposed. The main product ions of obtained derivatives for 21 anabolic steroids were evaluated and fragmentation pathways were compared.The analysis of MS/MS spectra for underivatized steroids versus oxime or picolinoyl derivatives showed that in case of analytes containing conjugated double bonds in sterane core all of the observed MS/MS spectra contained abundant product ions of diagnostic value. The implementation of derivatization procedures to such compounds is useful for upgrading sensitivity or selectivity of the evaluated method. On the other hand, MS/MS spectra of underivatized and oxime analytes without conjugated double bonds in sterane core produce spectra with large amounts of low abundant product ions. Picolinoyl derivatives formation leads to highly specific spectra with product ions of diagnostic value coupled with sensitive and selective analysis at the same time. The intra- and inter-group comparison analysis revealed that fragmentation pathways for underivatized steroids and correspondent oxime derivatives are similar.The obtained oxime and picolinoyl derivatives provided 10-15 times higher ESI response in the HPLC-ESI-MS-selected reaction monitoring (SRM) when compared to those of underivatized molecules in positive HPLC-ESI-MS mode.Due to the laborious sample preparation we suggest to use the performed strategy for confirmation analysis purposes, metabolic studies or while the identification of new steroids or steroid-like substances.

  16. On-line amino acid-based capillary isoelectric focusing-ESI-MS/MS for protein digests analysis.

    PubMed

    Zhu, Guijie; Sun, Liangliang; Yang, Ping; Dovichi, Norman J

    2012-10-31

    Six amino acids with pIs that ranged from 3.2 to 9.7 were used as ampholytes to establish a pH gradient in capillary isoelectric focusing. This amino acid-based capillary isoelectric focusing (cIEF) was coupled with ESI-MS/MS using an electrokinetically pumped sheath-flow interface for peptide analysis. Amino acid-based isoelectric focusing generates a two-order of magnitude lower background signal than commercial ampholytes in the important m/z range of 300-1800. Good focusing was achieved for insulin receptor, which produced ~10 s peak width. For 0.1 mg mL(-1) bovine serum albumin (BSA) digests, 24±1 peptides (sequence coverage 47±4%) were identified in triplicate analysis. As expected, the BSA peptides were separated according to their pI. The concentration detection limit for the BSA digests is 7 nM and the mass detection limit is 7 fmole. A solution of six bovine protein tryptic digests spanning 5 orders of magnitude in concentration was analyzed by amino acid based cIEF-ESI-MS/MS. Five proteins with a concentration range spanning 4 orders of magnitude were identified in triplicate runs. Using amino acid based cIEF-ESI-MS/MS, 112 protein groups and 303 unique peptides were identified in triplicate runs of a RAW 264.7 cell homogenate protein digest. In comparison with ampholyte based cIEF-ESI-MS/MS, amino acid based cIEF-ESI-MS/MS produces higher resolution of five acidic peptides, much cleaner mass spectra, and higher protein spectral counts.

  17. LA-ICP-MS of magnetite: Methods and reference materials

    USGS Publications Warehouse

    Nadoll, P.; Koenig, A.E.

    2011-01-01

    Magnetite (Fe3O4) is a common accessory mineral in many geologic settings. Its variable geochemistry makes it a powerful petrogenetic indicator. Electron microprobe (EMPA) analyses are commonly used to examine major and minor element contents in magnetite. Laser ablation ICP-MS (LA-ICP-MS) is applicable to trace element analyses of magnetite but has not been widely employed to examine compositional variations. We tested the applicability of the NIST SRM 610, the USGS GSE-1G, and the NIST SRM 2782 reference materials (RMs) as external standards and developed a reliable method for LA-ICP-MS analysis of magnetite. LA-ICP-MS analyses were carried out on well characterized magnetite samples with a 193 nm, Excimer, ArF LA system. Although matrix-matched RMs are sometimes important for calibration and normalization of LA-ICP-MS data, we demonstrate that glass RMs can produce accurate results for LA-ICP-MS analyses of magnetite. Cross-comparison between the NIST SRM 610 and USGS GSE-1G indicates good agreement for magnetite minor and trace element data calibrated with either of these RMs. Many elements show a sufficiently good match between the LA-ICP-MS and the EMPA data; for example, Ti and V show a close to linear relationship with correlation coefficients, R2 of 0.79 and 0.85 respectively. ?? 2011 The Royal Society of Chemistry.

  18. Towards establishing MS prevalence in Latin America and the Caribbean.

    PubMed

    Melcon, M O; Melcon, C M; Bartoloni, L; Cristiano, E; Duran, J C; Grzesiuk, A K; Fragoso, Y D; Brooks, J B Bidin; Díaz, V; Romero García, K M; Cabrera Gomez, J A; Abad, P; Islas, M A Macías; Gracia, F; Diaz de Bedoya, V F Hamuy; Ruiz, M E Córdova; Hackembruch, J H; Oehninger, C; Ketzoian, C N; Soto, A

    2013-02-01

    A very high prevalence of multiple sclerosis (MS) has been reported in some Western European and North American countries. The few surveys of MS epidemiology in South America reveal lower prevalence rates, implying that susceptibility varies between distinct ethnic groups, thus forming an important determinant of the geographic distribution of the disease. The objective of this study is to review MS prevalence estimates in different Latin American and Caribbean countries. We reviewed surveys of regional MS prevalence from 1991 to 2011. Sources included an online database, authors' reports and proceedings or specific lectures from regional conferences. We obtained a total of 30 prevalence surveys from 15 countries, showing low/medium MS prevalence rates. Both the number and the quality of prevalence surveys have greatly improved in this region over recent decades. This is the first collaborative study to map the regional frequency of MS. Establishment of standardized methods and joint epidemiological studies will advance future MS research in Latin America and the Caribbean.

  19. Laser desorption postionization for imaging MS of biological material.

    PubMed

    Akhmetov, Artem; Moore, Jerry F; Gasper, Gerald L; Koin, Peter J; Hanley, Luke

    2010-02-01

    Vacuum ultraviolet single photon ionization (VUV SPI) is a soft ionization technique that has the potential to address many of the limitations of matrix-assisted laser desorption/ionization (MALDI) for imaging MS. Laser desorption postionization (LDPI) uses VUV SPI for postionization and is experimentally analogous to a MALDI instrument with the addition of a pulsed VUV light source. This review discusses progress in LDPI-MS over the last decade, with an emphasis on imaging MS of bacterial biofilms, analytes whose high salt environment make them particularly resistant to imaging by MALDI-MS. This review first considers fundamental aspects of VUV SPI including ionization mechanisms, cross sections, quantum yields of ionization, dissociation and potential mass limits. The most common sources of pulsed VUV radiation are then described along with a newly constructed LDPI-MS instrument with imaging capabilities. Next, the detection and imaging of small molecules within intact biofilms is demonstrated by LDPI-MS using 7.87 eV (157.6 nm) VUV photons from a molecular fluorine excimer laser, followed by the use of aromatic tags for detection of selected species within the biofilm. The final section considers the future prospects for imaging intact biological samples by LDPI-MS.

  20. Backscatter Mossbauer Spectrometer (BaMS) for extraterrestrial applications

    NASA Astrophysics Data System (ADS)

    Agresti, D. G.; Shelfer, T. D.; Pimperl, M. M.; Wills, E. L.; Shen, M. H.; Morris, R. V.

    1993-06-01

    Mossbauer spectroscopy is a nuclear gamma resonance technique particularly well suited to the study of materials that contain iron (Fe-57). It can provide information on the oxidation state of iron as well as the type and proportion of iron-containing mineral species in a sample of interest. Iron Mossbauer spectroscopy (FeMS) has been applied to samples believed to have come from Mars (SNC meteorites) and has been helpful in refining the choice among putative Martian surface materials by suggesting a likely nanophase component of the Martian regolity. FeMS spectrum of a Martial analogue material (Hawaiian palagonite) is shown; it is dominated by ferric-bearing phases and shows evidence of a nanophase component. FeMS has also been applied to lunar materials. It can be used to measure the maturity of lunar surface material and has been proposed as a prospector for lunar ilmenite, an oxygen resource mineral. Several years ago we suggested a backscatter Mossbauer spectrometer (BaMS) for a Mars rover mission. Backscatter design was selected as most appropriate for in-situ application because no sample preparation is required. Since that time, we have continued to develop the BaMS instrument in anticipation that it would eventually find a home on a NASA planetary mission. Gooding proposed BaMS as a geochemistry instrument on MESUR. More recently, an LPI workshop has recommended that BaMS be included in a three-instrument payload on the next (1996?) lunar lander.

  1. Backscatter Mossbauer Spectrometer (BaMS) for extraterrestrial applications

    NASA Technical Reports Server (NTRS)

    Agresti, D. G.; Shelfer, T. D.; Pimperl, M. M.; Wills, E. L.; Shen, M. H.; Morris, R. V.

    1993-01-01

    Mossbauer spectroscopy is a nuclear gamma resonance technique particularly well suited to the study of materials that contain iron (Fe-57). It can provide information on the oxidation state of iron as well as the type and proportion of iron-containing mineral species in a sample of interest. Iron Mossbauer spectroscopy (FeMS) has been applied to samples believed to have come from Mars (SNC meteorites) and has been helpful in refining the choice among putative Martian surface materials by suggesting a likely nanophase component of the Martian regolity. FeMS spectrum of a Martial analogue material (Hawaiian palagonite) is shown; it is dominated by ferric-bearing phases and shows evidence of a nanophase component. FeMS has also been applied to lunar materials. It can be used to measure the maturity of lunar surface material and has been proposed as a prospector for lunar ilmenite, an oxygen resource mineral. Several years ago we suggested a backscatter Mossbauer spectrometer (BaMS) for a Mars rover mission. Backscatter design was selected as most appropriate for in-situ application because no sample preparation is required. Since that time, we have continued to develop the BaMS instrument in anticipation that it would eventually find a home on a NASA planetary mission. Gooding proposed BaMS as a geochemistry instrument on MESUR. More recently, an LPI workshop has recommended that BaMS be included in a three-instrument payload on the next (1996?) lunar lander.

  2. Tandem DART™ MS Methods for Methadone Analysis in Unprocessed Urine.

    PubMed

    Beck, Rachel; Carter, Patrick; Shonsey, Erin; Graves, David

    2016-03-01

    Current methods of methadone analysis in untreated urine are traditionally limited to enzyme immunoassays (EIA) while confirmation techniques require specimen processing (i.e., sample clean-up) before analyzing by gas or liquid chromatography coupled with mass spectrometry (GC-MS or LC-MS-MS). EIA and traditional confirmation techniques can be costly and, at times inefficient. As an alternative approach, we present Direct Analysis in Real Time (DART™) coupled with both time-of-flight and triple quadrupole linear ion trap (Q-TRAP™) mass spectrometers for screening and confirming methadone in untreated urine specimens. These approaches require neither expensive kits nor sample clean-up for analysis. More importantly, the total combined analysis time for both screening and confirmation methods was <5 min per sample; in contrast to the 3-5 day process required by traditional EIA, GC-MS and LC-MS-MS techniques. To examine the fundamental protocol and its applicability for routine drug screening, studies were performed that included limits of detection, precision, selectivity and specificity, sample recovery and stability and method robustness. The methods described in this report were determined to be highly specific and selective; allowing for detection of methadone at 250 ng/mL, consistent with cutoffs for current EIA techniques (300 ng/mL). The results reported here demonstrate the DART™ MS platform provides rapid and selective methadone analysis and the potential for providing savings of both time and resources compared with current analysis procedures.

  3. Combinatorial approach of LC-MS/MS and LC-TOF-MS for uncovering in vivo kinetics and biotransformation of ochratoxin A in rat.

    PubMed

    Han, Zheng; Zhao, Zhiyong; Shi, Jianxin; Liao, Yucai; Zhao, Zhihui; Zhang, Dabing; Wu, Yongning; De Saeger, Sarah; Wu, Aibo

    2013-04-15

    A combinatorial platform of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography coupled with time of flight mass spectrometry (LC-TOF-MS) has been developed to investigate the in vivo kinetics and biotransformation of ochratoxin A (OTA) in rats. The stable isotope dilution LC-MS/MS method was first validated by determining the linearity (R(2)≥0.9990), sensitivity (lower limit of quantitation of 0.05 ng mL(-1)), accuracy (83.3-108.3), precision (RSD≤15.6%) and stability (≥75.0%), and was approved for the determination OTA in plasma, heart, liver, spleen, lung, kidney and brain with a run time of 7.0 min. Simultaneously, an LC-TOF-MS method could unambiguously identify the metabolites of OTA in a total run time of 14 min. The subsequent studies on kinetics and distribution after oral administration of 0.2 mg/kg b.w. OTA in rat indicated that OTA could reach a maximum value of 1932.4±124.9 ng mL(-1) within 5h due to its fast absorption, and then was slowly eliminated in plasma with a half-life time (t1/2) of 75.6±29.0 h. Results of tissue accumulation after a daily oral administration of 0.1 mg/kg b.w. OTA during 20 days showed that the highest concentration of OTA was observed in lung (95.9±13.7 ng g(-1)), followed by liver (76.0±9.7 ng g(-1)), heart (62.0±4.2 ng g(-1)) and kidney (55.7±4.7 ng g(-1)). Furthermore, three less toxic metabolites of OTA were clearly identified: Ochratoxin β (OTβ) and ochratoxin B (OTB) methyl ester were found in kidney and spleen, respectively, while phenylalanine was detected in heart and kidney. Thus, a possible metabolic pathway of OTA was proposed. The above achieved results justified that the application of combinatorial LC-MS/MS and LC-TOF-MS methods are valuable tools to uncover the kinetics and metabolism of OTA for the interpretation of toxicological findings in animals and extrapolation of the resulting data as reference to humans.

  4. Importance of MS selectivity and chromatographic separation in LC-MS/MS-based methods when investigating pharmaceutical metabolites in water. Dipyrone as a case of study.

    PubMed

    Ibáñez, M; Gracia-Lor, E; Sancho, J V; Hernández, F

    2012-08-01

    Pharmaceuticals are emerging contaminants of increasing concern because of their presence in the aquatic environment and potential to reach drinking-water sources. After human and/or veterinary consumption, pharmaceuticals can be excreted in unchanged form, as the parent compound, and/or as free or conjugated metabolites. Determination of most pharmaceuticals and metabolites in the environment is commonly made by liquid chromatography (LC) coupled to mass spectrometry (MS). LC coupled to tandem MS is the technique of choice nowadays in this field. The acquisition of two selected reaction monitoring (SRM) transitions together with the retention time is the most widely accepted criterion for a safe quantification and confirmation assay. However, scarce attention is normally paid to the selectivity of the selected transitions as well as to the chromatographic separation. In this work, the importance of full spectrum acquisition high-resolution MS data using a hybrid quadrupole time-of-flight analyser and/or a suitable chromatographic separation (to reduce the possibility of co-eluting interferences) is highlighted when investigating pharmaceutical metabolites that share common fragment ions. For this purpose, the analytical challenge associated to the determination of metabolites of the widely used analgesic dipyrone (also known as metamizol) in urban wastewater is discussed. Examples are given on the possibilities of reporting false positives of dypirone metabolites by LC-MS/MS under SRM mode due to a wrong assignment of identity of the compounds detected.

  5. Multicenter experiment for quality control of peptide-centric LC-MS/MS analysis - A longitudinal performance assessment with nLC coupled to orbitrap MS analyzers.

    PubMed

    Campos, Alex; Díaz, Ramón; Martínez-Bartolomé, Salvador; Sierra, Jose; Gallardo, Oscar; Sabidó, Eduard; López-Lucendo, Maria; Ignacio Casal, J; Pasquarello, Carla; Scherl, Alexander; Chiva, Cristina; Borras, Eva; Odena, Antonia; Elortza, Félix; Azkargorta, Mikel; Ibarrola, Nieves; Canals, Francesc; Albar, Juan P; Oliveira, Eliandre

    2015-09-08

    Proteomic technologies based on mass spectrometry (MS) have greatly evolved in the past years, and nowadays it is possible to routinely identify thousands of peptides from complex biological samples in a single LC-MS/MS experiment. Despite the advancements in proteomic technologies, the scientific community still faces important challenges in terms of depth and reproducibility of proteomics analyses. Here, we present a multicenter study designed to evaluate long-term performance of LC-MS/MS platforms within the Spanish Proteomics Facilities Network (ProteoRed-ISCIII). The study was performed under well-established standard operating procedures, and demonstrated that it is possible to attain qualitative and quantitative reproducibility over time. Our study highlights the importance of deploying quality assessment metrics routinely in individual laboratories and in multi-laboratory studies. The mass spectrometry data have been deposited to the ProteomeXchange Consortium with the data set identifier PXD000205.This article is part of a Special Issue entitled: HUPO 2014.

  6. Identified EM Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth, II; Saxton, Patrick

    2014-05-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After a number of custom rock experiments, two hypotheses were formed which could answer the EM wave model. The first hypothesis concerned a sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio transmission. Electron flow along fracture surfaces was determined to be inadequate in creating strong EM fields, because rock has a very high electrical resistance making it a high quality insulator. Penetrative flow could not be corroborated as well, because it was discovered that rock was absorbing and confining electrons to a very thin skin depth. Radio wave transmission and detection worked with every single test administered. This hypothesis was reviewed for propagating, long-wave generation with sufficient amplitude, and the capability of penetrating solid rock. Additionally, fracture spaces, either air or ion-filled, can facilitate this concept from great depths and allow for surficial detection. A few propagating precursor signals have been detected in the field occurring with associated phases using custom-built loop antennae. Field testing was conducted in Southern California from 2006-2011, and outside the NE Texas town of Timpson in February, 2013. The antennae have mobility and observations were noted for

  7. Ni speciation in tea infusions by monolithic chromatography--ICP-MS and Q-TOF-MS.

    PubMed

    Ščančar, Janez; Zuliani, Tea; Žigon, Dušan; Milačič, Radmila

    2013-02-01

    For humans, Ni is not considered to be an essential trace element. Its compounds, at levels present in foodstuffs and drinks, are generally considered to be safe for consumption, but for individuals who already suffer from contact allergy to Ni and may be subject to develop systemic reactions from its dietary ingestion, dietary exposure to Ni must be kept under control. Being the second most popular beverage, tea is a potential source of dietary Ni. Present knowledge on its speciation in tea infusions is poor. Therefore, complete speciation analysis, consisting of separation by liquid chromatography using a weak CIM DEAE-1 monolithic column, "on-line" detection by inductively coupled plasma mass spectrometry (ICP-MS) and "off-line" identification of ligands by hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MS), was implemented for the first time to study Ni speciation in tea infusions. Total concentrations of Ni in dry leaves of white, green, oolong and black tea (Camellia sinensis) and flowers of herbal chamomile (Matricaria chamomilla) and hibiscus (Hibiscus sabdariffa) tea were determined after microwave digestion by ICP-MS. They lay between 1.21 and 14.4 mg kg(-1). Good agreement between the determined and the certified values of the Ni content in the standard reference material SRM 1573a tomato leaves confirmed the accuracy of the total Ni determination. During the infusion process, up to 85 % of Ni was extracted from tea leaves or flowers. Separation of Ni species was completed in 10 min by applying aqueous linear gradient elution with 0.6 mol L(-1) NH(4)NO(3). Ni was found to be present in the chromatographic fraction in which quinic acid was identified by Q-TOF in all the tea infusions analysed, which had pH values between 5.6 and 6.0. The only exception was the infusion of hibiscus tea with a pH of 2.7, where results of speciation analysis showed that Ni is present in its divalent ionic form.

  8. LC-MS of novel narcoepileptics and related substances.

    PubMed

    Rao, Ramisetti Nageswara; Shinde, Dhananjay D; Ramesh, Venna; Srinivas, Ragampeta

    2009-05-01

    Modafinil, adrafinil and their related substances were synthesized and analyzed by RP-LC with ESI-MS/MS. The ionization mode, polarity, cone voltage, and chromatographic conditions were evaluated. The optimum LC-MS conditions to obtain fragment ions indispensable for identification of the structures were described. The bulk drugs purity of modafinil and adrafinil was evaluated on Kromasil C(18) column with ACN/0.02 M ammonium acetate as mobile phase in gradient elution mode at 30 degrees C. The method was found to be suitable not only for monitoring the reactions during the process development but also for quality assurance of modafinil and adrafinil.

  9. Analysis of drugs of abuse in hair: evaluation of the immunochemical method VMA-T vs. LC-MS/MS or GC-MS.

    PubMed

    Baumgartner, Markus R; Guglielmello, Rosetta; Fanger, Monique; Kraemer, Thomas

    2012-02-10

    Hair analysis is an elaborate and time-consuming multi-step process. The immunometric test VMA-T from Comedical has been evaluated as screening assay for hair analysis. From routine work, authentic samples were selected that were positive for opiates, cocaine, MDMA-type drugs, amphetamines, methadone or THC. These hair samples were investigated by LC-MS or GC-MS and the VMA-T procedure, respectively. Using the cut-off values recommended by the Society of Hair Testing, the VMA-T method discriminates with good sensitivity between negative and positive hair samples and is an expedient screening method for drugs in keratinized matrices such as hair. In order to save time and resources, the residue of the VMA-T extraction solution can be reused for confirmation analysis by LC-MS except for cocaine.

  10. Nonanthocyanin secondary metabolites of black raspberry (Rubus occidentalis L.) fruits: identification by HPLC-DAD, NMR, HPLC-ESI-MS, and ESI-MS/MS analyses.

    PubMed

    Paudel, Liladhar; Wyzgoski, Faith J; Scheerens, Joseph C; Chanon, Ann M; Reese, R Neil; Smiljanic, Danijela; Wesdemiotis, Chrys; Blakeslee, Joshua J; Riedl, Kenneth M; Rinaldi, Peter L

    2013-12-11

    Nonanthocyanin secondary metabolites potentially contributing to the antiproliferative bioactivity of black raspberry ( Rubus occidentalis L.) fruits were extracted in ethyl acetate and isolated by semipreparative and analytical HPLC and analyzed by NMR, HPLC-ESI-MS, and ESI-MS/MS techniques. Here we present complete and partial structures of a variety of the chemical entities such as quercetin 3-glucoside, quercetin 3-rutinoside, myricetin glucoside, dihydrokaempferol glucoside, benzoic acid β-d-glucopyranosyl ester, 3,4-dihydroxybenzoic acid, epicatechin, caffeic acid, p-coumaric acid, p-coumaryl glucoside, p-coumaryl sugar ester, ellagic acid, methyl ellagic acid acetylpentose, methyl ellagic acid valerylpentose, trans-piceid, phloretin glucoside (phloridzin), dihydrosinapic acid, salicylic acid β-d-glucopyranosyl ester, a salicylic acid derivative without attached sugar, p-alkylphenyl glucoside, and a citric acid derivative. To our knowledge, 15 of these compounds were not previously reported in black raspberry fruits.

  11. Stability-indicating HPLC method development and structural elucidation of novel degradation products in posaconazole injection by LC-TOF/MS, LC-MS/MS and NMR.

    PubMed

    Yang, Yidi; Zhu, Xi; Zhang, Fei; Li, Wei; Wu, Ying; Ding, Li

    2016-06-05

    Stress testing was carried out under acidic, alkaline, oxidative, thermal and photolytic conditions to evaluate the intrinsic stability of posaconazole injection. A total of four degradation products were detected and the drug was found to be susceptible to oxidative and thermal degradations. Three unknown degradants formed under oxidative stress condition were isolated by preparative HPLC and unambiguously elucidated by LC-TOF/MS, LC-MS/MS, (1)H NMR, (13)C NMR and 2D NMR techniques. Based on the spectrometric and spectroscopic information, these novel degradation products were unequivocally assigned as the N-oxides of posaconazole. Probable mechanisms for the formation of the degradants were proposed. A new and selective HPLC method was developed and validated to separate, detect and quantify all the degradants in posaconazole injection.

  12. Identification of amygdalin and its major metabolites in rat urine by LC-MS/MS.

    PubMed

    Ge, B Y; Chen, H X; Han, F M; Chen, Y

    2007-10-01

    Amygdalin and its metabolites in rat urine were identified using liquid chromatography-electrospray ionization (ESI) tandem ion-trap mass spectrometry. The purified rat urine sample was separated using a reversed-phase C18 column with 10 mM sodium phosphate buffer (pH 3.1) containing 30% methanol as the mobile phase, amygdalin and its metabolites were detected by on-line mass detector in selected ion monitoring (SIM) mode. The identification of the metabolites and elucidation of their structure were performed by comparing the changes in molecular masses (DeltaM), retention times and MS(2) spectral patterns of metabolites with those of parent drug. At least seven metabolites and the parent drug were found in rat urine after i.v. injection of 100 mg/kg doses of amygdalin. Among them, six metabolites were reported for the first time.

  13. Matrix effect marker for multianalyte analysis by LC-MS/MS in biological samples.

    PubMed

    Tudela, Eva; Muñoz, Gloria; Muñoz-Guerra, Jesús A

    2012-07-15

    Matrix effects (ion suppression/enhancement) are a well-observed phenomenon in analyses of biological matrices by high-performance liquid chromatography-mass spectrometry (LC-MS). However, few simple solutions for detecting and minimizing these adverse effects have been described so far in multianalyte analysis, especially in the field of doping control. This study describes an exhaustive characterization of matrix effects in one hundred urine samples fortified with 41 analytes (glucocorticoids and diuretics). It introduces a novel marker to identify samples in which the reliability of the results is compromised because of acute ion suppression. This new strategy strengthens the rigor of the analysis for screening purposes. Once the matrix effect is identified, a selective sample preparation is introduced to minimize the adverse ion suppression effect. That selective extraction together with the use of a deuterated internal standard permits enhancing the ruggedness of the estimation of glucocorticoid concentration in urine.

  14. LC-MS quantification of protein drugs: validating protein LC-MS methods with predigestion immunocapture.

    PubMed

    Duggan, Jeffrey; Ren, Bailuo; Mao, Yan; Chen, Lin-Zhi; Philip, Elsy

    2016-09-01

    A refinement of protein LC-MS bioanalysis is to use predigestion immunoaffinity capture to extract the drug from matrix prior to digestion. Because of their increased sensitivity, such hybrid assays have been successfully validated and applied to a number of clinical studies; however, they can also be subject to potential interferences from antidrug antibodies, circulating ligands or other matrix components specific to patient populations and/or dosed subjects. The purpose of this paper is to describe validation experiments that measure immunocapture efficiency, digestion efficiency, matrix effect and selectivity/specificity that can be used during method optimization and validation to test the resistance of the method to these potential interferences. The designs and benefits of these experiments are discussed in this report using an actual assay case study.

  15. Comparison of sp-ICP-MS and MDG-ICP-MS for the determination of particle number concentration.

    PubMed

    Gschwind, Sabrina; Aja Montes, Maria de Lourdes; Günther, Detlef

    2015-05-01

    In 2011, the European Commission introduced new regulations on how nanomaterials are defined. Since then, researchers have emphasized that more complete characterization of nanoparticles (NPs) includes not just mass and size determinations, but also the determination of the particle number concentrations. In this study, two different sample introduction approaches for the analysis of NP suspensions with inductively coupled plasma mass spectrometry (ICP-MS) were investigated: pneumatic nebulization (sp-ICP-MS) and microdroplet generation (MDG-ICP-MS). These approaches were compared for the determination of particle number concentrations (PNCs) of gold and silver NP suspensions diluted in either ultra-pure water or citrate solution. For accurate sp-ICP-MS analysis, it is crucial to know the transport efficiency of nebulized sample into the plasma. Here, transport efficiencies, measured by the waste collection method, were 11-14 % for Ag suspensions and 9-11 % for Au. In contrast, the droplet transport efficiency of MDG-ICP-MS was 100 %. Analysis by sp-ICP-MS yielded a lower particle number concentration than expected (only 20-40 % of the expected value), whereas MDG-ICP-MS had NP recoveries up to 80 %. This study indicates that NP reference materials are of major importance for particle number determination and detailed results on particle number concentrations for different suspensions with respect to storage time are discussed.

  16. LC-MS/MS determination of pesticide residues in fruits and vegetables.

    PubMed

    Stachniuk, Anna; Szmagara, Agnieszka; Czeczko, Renata; Fornal, Emilia

    2017-03-29

    The aim of the research is to evaluate pesticide residue contamination of fresh and frozen fruits and vegetables, agricultural raw material, purchased from Polish farmers for production of frozen fruits and vegetables, and the estimation of the multiresidue method effectiveness expressed as the proportion of pesticides detected in food samples to the total number of pesticides analyzed by multiresidue methods. A total of 144 samples (of black currants, red currants, raspberries, cherries, strawberries, blackberries, cauliflowers and broccoli) were analyzed using LC-MS/MS method for the determination of 60 pesticides. QuEChERS extraction, matrix-matched calibration and dynamic multiple reaction monitoring method were used. Residues of 15 compounds, mainly fungicides and insecticides, were detected in 46 samples. The percentage of samples with residues above the maximum residue levels (MRL) was 15%, whereas samples with residues below MRL were 17%. A total of 13 samples contained more than one pesticide residue. Pesticide residues were detected most often in samples of black currants (50%), broccoli (36.4%), raspberries (29%) and red currants (21.8%). The most frequently detected pesticides were carbendazim and acetamiprid. The proportion of pesticides detected during our study to the total number of analyzed pesticides amounted to 25%. It was compared to literature findings. For three fourth of multiresidue methods, the proportion was below 50% for methods developed for the analysis of less than 100 pesticides, and below 30% for methods developed for the analysis of more than 100 pesticides. It appears that a lot of efforts and means is lost on pesticides never or rarely detected in examined samples. The workload and cost effectiveness of the development and application of multiresidue methods along with the range of pesticides covered by the method should be carefully and thoroughly considered anytime when a new method or workflow is developed. Including non

  17. Identification of in vitro and in vivo metabolites of alantolactone by UPLC-TOF-MS/MS.

    PubMed

    Yao, Donggui; Li, Zhe; Huo, Changhong; Wang, Yufang; Wu, Yibing; Zhang, Manli; Li, Ligeng; Shi, Qingwen; Kiyota, Hiromasa; Shi, Xiaowei

    2016-10-15

    Alantolactone (AL), an active sesquiterpene originating from Inula helenium, is a potential anticancer and anti-inflammatory agent. However so far, studies on AL metabolism have not been reported. In the present study, we have investigated for the first time the in vivo and in vitro metabolites of AL using ultra performance liquid chromatography combined with time of flight mass spectrometry (UPLC-TOF-MS/MS). A unique on-line information-dependent acquisition (IDA) method multiple mass defect filter (MMDF) combined with dynamic background subtraction (DBS) was applied to trace all of the probable metabolites of AL. Five MMDF templates were set according to the core structure of AL and the general metabolite biotransformation patterns, and other five sulfur-containing dimer filter templates were first established on the basis of structural elucidation of AL metabolites obtained from rat intestinal bacteria biotransformation. As a result, 44 metabolites were characterized: 41 metabolites from rat urine, bile and feces after oral administration of AL, and 13 metabolites from AL biotransformation by rat intestinal bacteria. Particularly, 26 metabolites were identified as novel sulfur-containing products. The results indicated that addition of double bond at Δ((11,13)) and oxidization were the main metabolic reactions of AL. A new metabolism pathway to produce addition products of H2S to AL and further generate a series of sulfur-containing dimers of AL was revealed. This study significantly enriched our knowledge about AL metabolism, which will lead to a better understanding of the safety and efficacy of AL. At the same time, the established methodology can be widely applied for the structural determination of the metabolites of other sesquiterpene containing α-methylene-γ-lactone moiety.

  18. Multi-class determination of anthelmintics in soil and water by LC-MS/MS.

    PubMed

    Islam, Marivil D; Haberhauer, Georg; Kist, Alla; Rathor, M Nasir; Gerzabek, Martin; Cannavan, Andrew

    2013-01-01

    The translocation of antiparasitic drugs from animal excrement through soil and water to crops and forages and their recycling to food-producing animals is a potential concern with respect to the contamination of the food chain. To facilitate the investigation of this problem, an LC-MS/MS method for selected anthelmintics in soil and water was developed. The soil sample preparation involved a simple solvent extraction and dispersive clean-up technique. The method was validated at 10, 20 and 40 µg kg(-1) for levamisole, fenbendazole, fenbendazole sulphoxide and fenbendazole sulphone and at 20, 40 and 80 µg kg(-1) for eprinomectin. LOQs were 10 µg kg(-1) for the first four compounds and 20 µg kg(-1) for eprinomectin. The overall mean recoveries ranged from 76.1% to 89% for loamy soils and from 79.9% to 96.9% for sandy soils. Analysis of water samples was performed by extraction/concentration on an Oasis-HLB (Aschaffenburg, Germany) cartridge. Validation was performed at 0.25, 0.5 and 1.0 µg l(-1). The LOQ for all compounds was 0.25 µg l(-1). Method recovery (and RSD) varied between 35.4% (28) for eprinomectin and 125.1% (16) for fenbendazole sulphone. The validated methods were applied to soil and water samples in a study on the behaviour of anthelmintic drugs in a soil-plant-water system (manuscript on "transport investigation of antiparasitic drugs based on a lysimeter experiment" in preparation).

  19. LC-MS-MS simultaneous determination of atorvastatin and ezetimibe in human plasma.

    PubMed

    El-Bagary, Ramzia I; Elkady, Ehab F; El-Sherif, Zeinab Abdelaziz; Kadry, Ahmed M

    2014-09-01

    Atorvastatin and ezetimibe are lipid-lowering drugs prescribed for the treatment of hypercholesterolemia. An LC-MS-MS method has been developed and validated for the simultaneous estimation of atorvastatin and ezetimibe in human plasma using pitavastatin as an internal standard. Liquid-liquid extraction was used for the purification and preconcentration of analytes from human plasma matrix. The chromatographic separation was achieved within 3.0 min by an isocratic mobile phase consisting of 0.2% formic acid in water-acetonitrile (30:70, v/v), flowing through Agilent Eclipse-plus C18, 100 × 4.6 mm, 3.5 µm analytical column, at a flow rate of 0.6 mL min(-1). Multiple reaction monitoring transitions were measured in the positive ion mode for atorvastatin and internal standard, while ezetimibe was measured in negative ion mode. A detailed validation of the method was performed as per US-FDA guidelines and the standard curves were found to be linear in the range of 0.2-30.0 ng mL(-1) with a mean correlation coefficient >0.999 for both drugs. In human plasma, atorvastatin and ezetimibe were stable for at least 36 days at -70 ± 5 °C and 6 h at ambient temperature. After extraction from plasma, the reconstituted samples of atorvastatin and ezetimibe were stable in an autosampler at ambient temperature for 6 h. Also, the cited drugs were stable in plasma samples upon subjecting to three freeze thaw cycles. The method is simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies of this combination.

  20. Enantioselective Determination of Polycyclic Musks in River and Wastewater by GC/MS/MS.

    PubMed

    Lee, Injung; Gopalan, Anantha-Iyengar; Lee, Kwang-Pill

    2016-03-22

    The separation of chiral compounds is an interesting and challenging topic in analytical chemistry, especially in environmental fields. Enantioselective degradation or bioaccumulation has been observed for several chiral pollutants. Polycyclic musks are chiral and are widely used as fragrances in a variety of personal care products such as soaps, shampoos, cosmetics and perfumes. In this study, the gas chromatographic separation of chiral polycyclic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclo-penta-γ-2-benzopyrane (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetra-hydronaphthalene (AHTN), 6-acetyl-1,1,2,3,3,5-hexamethylindane (AHDI), 5-acetyl-1,1,2,6-tetramethyl-3-iso-propylindane (ATII), and 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanone (DPMI) was achieved on modified cyclodextrin stationary phase (heptakis (2,3-di-O-methyl-6-O-tert-butyl-dimethylsilyl-β-CD in DV-1701)). Separation techniques are coupled to tandem mass spectrometry (MS-MS), as it provides the sensitivity and selectivity needed. River and wastewaters (influents and effluents of wastewater treatment plants (WWTPs)) in the Nakdong River were investigated with regard to the concentrations and the enantiomeric ratios of polycyclic musks. HHCB was most frequently detected in river and wastewaters, and an enantiomeric enrichment was observed in the effluents of one of the investigated wastewater treatment plants (WWTPs). We reported the contamination of river and wastewaters in Korea by chiral polycyclic musks. The results of this investigation suggest that enantioselective transformation may occur during wastewater treatment.

  1. LC-MS/MS quantification of salvinorin A from biological fluids.

    PubMed

    Caspers, Michael J; Williams, Todd D; Lovell, Kimberly M; Lozama, Anthony; Butelman, Eduardo R; Kreek, Mary Jeanne; Johnson, Matthew; Griffiths, Roland; Maclean, Katherine; Prisinzano, Thomas E

    2013-12-21

    A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided completely by simply diluting each sample to 10 % (v/v) acetonitrile, 1 % (v/v) formic acid and injecting under high aqueous conditions for analyte focusing. Extensive plasma sample preparation was investigated including protein precipitation, SPE column selection, and plasma particulate removal. Human plasma samples were centrifuged at 21,000 × gravity for 4 minutes to obtain clear particulate-free plasma, from which 300 μl was spiked with internal standard and loaded onto a C18 SPE column with a 100 mg mL(-1) loading capacity. Guard columns (C18, hand packed 1 mm × 20 mm) were exchanged after backpressure increased above 4600psi, about 250 injections. A shallow acetonitrile/water gradient was used, 29 to 33% CH3CN over 8 minutes to elute salvinorin A. Reduction of chemical noise was achieved using tandem mass spectrometry with multiple reaction monitoring while sensitivity increases were observed using a 50 μL injection volume onto a small bore analytical column (C18, 1 mm ID × 50 mm) thus increasing peak concentration. Limits of quantification were found to be 0.0125 ng mL(-1) (CSF) and 0.05 ng mL(-1) (plasma) with interday precision and accuracy below 1.7 % and 9.42 % (CSF) and 3.47 % and 12.37 % (plasma) respectively. This method was used to determine the concentration of salvinorin A from an in vivo Rhesus monkey study and a trial of healthy human research participants, using behaviorally active doses.

  2. LC–MS-MS Analysis of Urinary Biomarkers of Imazalil Following Experimental Exposures

    PubMed Central

    Faniband, Moosa H.; Littorin, Margareta; Ekman, Eva; Jönsson, Bo A.G.; Lindh, Christian H.

    2015-01-01

    Imazalil (IMZ) is a fungicide used in the cultivation of vegetables, such as cucumbers, in green houses or post-harvest on fruit to avoid spoilage due to fungal growth. Agricultural workers can be occupationally exposed to IMZ and the general public indirectly by the diet. The purpose of this study was to develop and validate an LC–MS-MS method for the analysis of IMZ in human urine. The method used electrospray ionization and selected reaction monitoring in the positive mode. Excellent linearity was observed in the range 0.5–100 ng/mL. The limit of detection of the method was 0.2 ng/mL, and the limit of quantitation 0.8 ng/mL. The method showed good within-run, between-run and between-batch precision, with a coefficient of variation <15%. The method was applied to analyze urine samples obtained from two human volunteers following experimental oral and dermal exposure. The excretion of IMZ seemed to follow a two-compartment model and first-order kinetics. In the oral exposure, the elimination half-life of IMZ in the rapid excretion phase was 2.6 and 1.9 h for the female and the male volunteer, respectively. In the slower excretion phase, it was 7.6 and 13 h, respectively. In the dermal exposure, the excretion seemed to follow a single-compartment model and first-order kinetics. The elimination half-life was 10 and 6.6 h for the female and the male volunteer, respectively. Although the study is limited to two volunteers, some information on basic toxicokinetics and metabolism of IMZ in humans is presented. PMID:26324206

  3. Stable-isotope GC-MS/MS determination of aminoethylcysteine ketimine decarboxylated dimer in biological samples

    PubMed Central

    Tsikas, Dimitrios; Evans, Christopher E.; Denton, Travis T.; Mitschke, Anja; Gutzki, Frank-Mathias; Pinto, John T.; Khomenko, Tetyana; Szabo, Sandor; Cooper, Arthur J.L.

    2012-01-01

    Aminoethylcysteine ketimine decarboxylated dimer [AECK-DD; systematic name: 1,2–3,4–5,6–7,8-octahydro-1,8a-diaza-4,6-dithiafluoren-9(8aH)-one] is a previously described metabolite of cysteamine that has been reported to be present in mammalian brain, urine, plasma, cells in culture and vegetables, and to possess potent anti-oxidative properties. Here, we describe a stable-isotope GC-MS/MS method for specific and sensitive determination of AECK-DD in biological samples. 13C2-AECK-DD was synthesized and used as the internal standard. Derivatization was carried out by N-pentafluorobenzylation with pentafluorobenzyl bromide in acetonitrile. Quantification was performed by selected-reaction monitoring of the mass transitions m/z 328 to m/z 268 for AECK-DD and m/z 330 to m/z 270 for 13C2-AECK-DD in the electron-capture negative-ion chemical ionization mode. The procedure was systematically validated for human plasma and urine samples. AECK-DD was not detectable in human plasma above ~ 4 nM, but was present in urine samples of healthy humans at a maximal concentration of 46 nM. AECK-DD was detectable in rat brain at very low levels of about 8 pmol/g wet weight. Higher levels of AECK-DD were detected in mouse brain (~1 nmol/g wet weight). Among nine dietary vegetables evaluated, only shallots were found to contain trace amounts of AECK-DD (~ 6.8 pmol/g fresh tissue). PMID:22858756

  4. Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS

    USGS Publications Warehouse

    Ferrer, I.; Furlong, E.T.

    2001-01-01

    A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples. This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode. Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate. Total method recoveries were higher than 71% in different water matrices. The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively. The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion. The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91. Detection limits for the methodology developed in this work were in the low nanogram-per-liter range. Concentration levels of BAC - ranging from 1.2 to 36.6 micrograms per liter - were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.

  5. Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS.

    PubMed

    Ferrer, I; Furlong, E T

    2001-06-15

    A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples. This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode. Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate. Total method recoveries were higher than 71% in different water matrices. The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively. The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion. The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91. Detection limits for the methodology developed in this work were in the low nanogram-per-liter range. Concentration levels of BAC--ranging from 1.2 to 36.6 micrograms per liter--were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.

  6. Quantification of coumarin in cinnamon and woodruff beverages using DIP-APCI-MS and LC-MS.

    PubMed

    Krieger, Sonja; Hayen, Heiko; Schmitz, Oliver J

    2013-10-01

    The use of the direct inlet probe-atmospheric-pressure chemical ionization (DIP-APCI) ion source developed in our laboratory coupled to a high resolution Q-TOF MS for the quantitative analysis of coumarin in different cinnamon samples was demonstrated in this study. Extraction of coumarin from various cinnamon samples was followed by DIP-APCI-mass spectrometry (MS) and liquid chromatography (LC)-MS analysis. For quantification, an external calibration with and without the use of stable isotope-labeled coumarin as internal standard was compared. The results obtained by DIP-APCI-MS and LC-MS were in good agreement. Even without the use of an internal standard satisfying linearity (R(2) > 0.997), recovery (94-104% for spiking levels between 100 and 5,000 mg/kg) and intra- and interday repeatability (2.2-13.8%RSD) was demonstrated using DIP-APCI-MS. To reduce the number of samples requiring quantitative analysis, the possibility of semi-quantitative screening of coumarin directly from powdered cinnamon using DIP-APCI-MS was shown. The analysis of woodruff-flavored beverages and cinnamon-flavored chewing gum by DIP-APCI-MS resulted in the formation of an artifact interfering with coumarin detection. As with other ambient ionization methods, special attention has to be paid to possible spectral interferences due to isobaric substances present in the sample matrix or formed from matrix components after ionization. The temperature-programmed vaporization in DIP-APCI-MS combined with the use of stable isotope-labeled coumarin as internal standard helped in recognizing this interference.

  7. Analysis of Rare Earth Elements in Rock and Mineral Samples by ICP-MS and LA-ICP-MS

    NASA Astrophysics Data System (ADS)

    Sindern, Sven

    2017-02-01

    The group of the rare earth elements (REEs) serves as valuable indicator of numerous geological processes such as magma formation or fluid-rock interaction. The decay systems of the radioactive REE isotopes 138La, 147Sm and 176Lu are used for geochronometric dating of a range of events, starting from first steps of planetary formation to younger steps of geodynamic development. Thus, the abundance of all REEs occurring in a large range of concentrations as well as precise isotope ratios must be analysed in different geomaterials. The inductively coupled plasma (ICP) ion source and various types of mass spectrometers (MS) represent the basis to fulfil the analytical requirements of geoscientific studies. Today, ICP-quadrupole MS and ICP-sector field MS (SFMS) with a single detector or multiple ion collection (MC-ICP-MS) are standard instruments for REE analyses in the geosciences. Due to the need for in situ analysis, laser ablation (LA)-ICP-MS has become an important trace element microprobe technique, which is widely applied for determination of REE concentrations and isotope compositions in geoscientific laboratories. The quality of concentration analysis or isotope ratio determination of REEs by ICP-MS and LA-ICP-MS is affected by many parameters. Most significant are interferences caused by polyatomic oxide and hydroxide ion species formed in the plasma as well as fractionation effects leading to non-stoichiometric behaviour during element determination or to biased isotope ratio measurements. Laser-induced fractionation and isobaric interferences have to be considered as additional effects for LA-ICP-MS. As analyte elements and matrix are unseparated, mineral standards matching the matrix of samples are a prerequisite for accurate and precise REE concentration and isotope ratio determination. Application of fs lasers instead of the more common ns lasers in LA-ICP-MS systems turns out to be a significant step to reduce laser-induced fractionation and to

  8. Separation and identification of DMPO adducts of oxygen-centered radicals formed from organic hydroperoxides by HPLC-ESR, ESI-MS and MS/MS.

    PubMed

    Guo, Qiong; Qian, Steven Y; Mason, Ronald P

    2003-08-01

    Many electron spin resonance (ESR) spectra of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) radical adducts from the reaction of organic hydroperoxides with heme proteins or Fe(2+) were assigned to the adducts of DMPO with peroxyl, alkoxyl, and alkyl radicals. In particular, the controversial assignment of DMPO/peroxyl radical adducts was based on the close similarity of their ESR spectra to that of the DMPO/superoxide radical adduct in conjunction with their insensitivity to superoxide dismutase, which distinguishes the peroxyl adducts from the DMPO/superoxide adduct. Although recent reports assigned the spectra suggested to be DMPO/peroxyl radical adducts to the DMPO/methoxyl adduct based on independent synthesis of the adduct and/or (17)O-labeling, (17)O-labeling is extremely expensive, and both of these assignments were still based on hyperfine coupling constants, which have not been confirmed by independent techniques. In this study, we have used online high performance liquid chromatography (HPLC or LC)/ESR, electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) to separate and directly characterize DMPO oxygen-centered radical adducts formed from the reaction of Fe(2+) with t-butyl or cumene hydroperoxide. In each reaction system, two DMPO oxygen-centered radical adducts were separated and detected by online LC/ESR. The first DMPO radical adduct from both systems showed identical chromatographic retention times (t(R) = 9.6 min) and hyperfine coupling constants (a(N) = 14.51 G, a(H)(beta) = 10.71 G, and a(H)(gamma) = 1.32 G). The ESI-MS and MS/MS spectra demonstrated that this radical was the DMPO/methoxyl radical adduct, not the peroxyl radical adduct as was thought at one time, although its ESR spectrum is nearly identical to that of the DMPO/superoxide radical adduct. Similarly, based on their MS/MS spectra, we verified that the second adducts (a(N) = 14.86 G and a(H)(beta) = 16.06 G in the reaction system containing t

  9. Mission Specialist (MS) Lenoir cuts Pilot Overmyer's hair on middeck

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Mission Specialist (MS) Lenoir, using hairbrush and scissors, cuts Pilot Overmyer's hair and trims his sideburns in front of forward middeck lockers. Personal hygiene kit (open), towels, meal tray assemblies, and field sequential (FS) crew cabincamera are attached to lockers.

  10. Mission Specialist (MS) Lenoir cuts Pilot Overmyer's hair on middeck

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Mission Specialist (MS) Lenoir, using hairbrush and scissors, cuts Pilot Overmyer's hair and trims his sideburns in front of forward middeck lockers. Personal hygiene kit (open), towels, and field sequential (FS) crew cabin camera are attached to lockers.

  11. New MS Drug Shows 'Breakthrough' Promise for Advanced Disease

    MedlinePlus

    ... News) -- A new drug slows the progress of multiple sclerosis, including an advanced form of the degenerative nerve ... also proved superior in treating people with relapsing multiple sclerosis, the most common form of MS, compared with ...

  12. 76 FR 5119 - Television Broadcasting Services; Jackson, MS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-28

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Jackson, MS AGENCY: Federal Communications... 73 Television, Television broadcasting. For the reasons discussed in the preamble, the...

  13. RadNet Air Data From Jackson, MS

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Jackson, MS from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  14. An LC-MS/MS method for serum methylmalonic acid suitable for monitoring vitamin B12 status in population surveys.

    PubMed

    Mineva, Ekaterina M; Zhang, Mindy; Rabinowitz, Daniel J; Phinney, Karen W; Pfeiffer, Christine M

    2015-04-01

    Methylmalonic acid (MMA), a functional indicator of vitamin B12 insufficiency, was measured in the US population in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004 using a GC/MS procedure that required 275 μL of sample and had a low throughput (36 samples/run). Our objective was to introduce a more efficient yet highly accurate LC-MS/MS method for NHANES 2011-2014. We adapted the sample preparation with some modifications from a published isotope-dilution LC-MS/MS procedure. The procedure utilized liquid-liquid extraction and generation of MMA dibutyl ester. Reversed-phase chromatography with isocratic elution allowed baseline resolution of MMA from its naturally occurring structural isomer succinic acid within 4.5 min. Our new method afforded an increased throughput (≤160 samples/run) and measured serum MMA with high sensitivity (LOD = 22.1 nmol/L) in only 75 μL of sample. Mean (±SD) recovery of MMA spiked into serum (2 d, 4 levels, 2 replicates each) was 94 % ± 5.5 %. Total imprecision (41 d, 2 replicates each) for three serum quality control pools was 4.9 %-7.9 % (97.1-548 nmol/L). The LC-MS/MS method showed excellent correlation (n = 326, r = 0.99) and no bias (Deming regression, Bland-Altman analysis) compared to the previous GC/MS method. Both methods produced virtually identical mean (±SD) MMA concentrations [LC-MS/MS: 18.47 ± 0.71 ng/mL (n = 17), GC/MS: 18.18 ± 0.67 ng/mL (n = 11)] on a future plasma reference material compared with a GC/MS method procedure from the National Institute of Standards and Technology [18.41 ± 0.70 ng/mL (n = 15)]. No adjustment will be necessary to compare previous (1999-2004) to future (2011-2014) NHANES MMA data.

  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. Analysis of Trichothecene Mycotoxins by Combined HPLC/MS.

    DTIC Science & Technology

    1986-04-15

    The development of HPLC/MS assays for the analysis of selected trichothecene mycotoxins in urine is the goal of this program. T-2 toxin has been the initial target of this investigation. Three important issues have been addressed before proceeding with the actual HPLC/MS experiments: the synthesis of isotopically labelled internal standards, efficient recovery of the target compounds from the urine matrix, and determination of HPLC conditions for their separation. Keywords: Mass spectrometry, High performance liquid chromatography , Phytotoxins.

  17. GC-MS investigation of tropane alkaloids in Datura stramonium.

    PubMed

    Philipov, Stefan; Berkov, Strahil

    2002-01-01

    Alkaloids, GS-MS, Datura stramonium The alkaloid spectrum in roots, leaves and seeds of Datura stramonium L. was investigated by GC-MS. Twenty-nine tropane alkaloids are detected. Twelve of them are new constituents for the species and the two tropane esters 3-(3'-acetoxytropoyloxy)tropane (21) and 3-(2'-hydroxytropoyloxy)tropane (26) are described for the first time.

  18. Elemental impurity analysis of mercuric iodide by ICP/MS

    SciTech Connect

    Cross, E.S.; Mroz, E.; Olivares, J.A.

    1993-06-01

    A method has been developed to analyze mercuric iodide (HgI{sub 2}) for elemental contamination using Inductively Coupled Plasma/Mass Spectroscopy (ICP/MS). This paper will discuss the ICP/MS method, the effectiveness of purification schemes for removing impurities from HgI{sub 2}, as well as preliminary correlations between HgI{sub 2} detector performance and elemental contamination levels.

  19. Elemental impurity analysis of mercuric iodide by ICP/MS

    SciTech Connect

    Cross, E.S. . Santa Barbara Operations); Mroz, E.; Olivares, J.A. )

    1993-01-01

    A method has been developed to analyze mercuric iodide (HgI[sub 2]) for elemental contamination using Inductively Coupled Plasma/Mass Spectroscopy (ICP/MS). This paper will discuss the ICP/MS method, the effectiveness of purification schemes for removing impurities from HgI[sub 2], as well as preliminary correlations between HgI[sub 2] detector performance and elemental contamination levels.

  20. How is MS-13 a Threat to US National Security?

    DTIC Science & Technology

    2009-02-12

    to hang out together, MS-13’s motivation, demographics, and initiation rituals are not unique. Like other street gangs, active members range in age...from broken homes.”49 MS-13’s initiation rituals are well established. To join the gang, an individual must submit to at least a 13 second beating by...Clair. Gangs in Central America. Washington D.C.: Congressional Research Service, Library of Congress, 10 May 2005. Romano , Andrew. "Machetes on

  1. A comparison of nLC-ESI-MS/MS and nLC-MALDI-MS/MS for GeLC-based protein identification and iTRAQ-based shotgun quantitative proteomics.

    PubMed

    Yang, Yong; Zhang, Sheng; Howe, Kevin; Wilson, David B; Moser, Felix; Irwin, Diana; Thannhauser, Theodore W

    2007-09-01

    The use of nLC-ESI-MS/MS in shotgun proteomics experiments and GeLC-MS/MS analysis is well accepted and routinely available in most proteomics laboratories. However, the same cannot be said for nLC-MALDI MS/MS, which has yet to experience such widespread acceptance, despite the fact that the MALDI technology offers several critical advantages over ESI. As an illustration, in an analysis of moderately complex sample of E. coli proteins, the use MALDI in addition to ESI in GeLC-MS/MS resulted in a 16% average increase in protein identifications, while with more complex samples the number of additional protein identifications increased by an average of 45%. The size of the unique peptides identified by MALDI was, on average, 25% larger than the unique peptides identified by ESI, and they were found to be slightly more hydrophilic. The insensitivity of MALDI to the presence of ionization suppression agents was shown to be a significant advantage, suggesting it be used as a complement to ESI when ion suppression is a possibility. Furthermore, the higher resolution of the TOF/TOF instrument improved the sensitivity, accuracy, and precision of the data over that obtained using only ESI-based iTRAQ experiments using a linear ion trap. Nevertheless, accurate data can be generated with either instrument. These results demonstrate that coupling nanoLC with both ESI and MALDI ionization interfaces improves proteome coverage, reduces the deleterious effects of ionization suppression agents, and improves quantitation, particularly in complex samples.

  2. PiMS: a data management system for structural proteomics.

    PubMed

    Morris, Chris

    2015-01-01

    PiMS (Protein Information Management System) is a laboratory information management system for protein scientists. It enables researchers to enter data, track samples, and report results during the production of recombinant proteins for structural and functional applications. PiMS is the only custom LIMS for protein production, recording data from the selected target to the sample of soluble protein. The xtalPIMS extension supports crystallogenesis and has recently been extended to support crystal fishing and crystal treatment. PiMS can be configured to match local working methods by defining protocols. These are used to provide templates for recording details of the experiments. PiMS will continue to be developed in response to the needs of users to provide a unified and extensible set of software tools for protein sciences. The vision for PiMS is that it will become the laboratory standard for protein-related data management. The Science and Technology Facilities Council (STFC) distributes PiMS free to academic users under the Community Model.

  3. Determination of pesticides in fatty matrices using gel permeation clean-up followed by GC-MS/MS and LC-MS/MS analysis: A comparison of low- and high-pressure gel permeation columns.

    PubMed

    David, Frank; Devos, Christophe; Dumont, Emmie; Yang, Zhen; Sandra, Pat; Huertas-Pérez, José Fernando

    2017-04-01

    Two low-pressure columns (Bio-Beads SX-3) and three high-pressure GPC columns were compared for clean-up of a wide range of pesticides in fatty matrices of vegetable or animal origin. The GPC fractions were analyzed by GC-MS/MS and LC-MS/MS without additional clean-up. The performance of the GPC clean-up on the five column types was compared in terms of solvent consumption, lipid removal, pesticide recovery and repeatability. It was found that for fatty matrices, mainly consisting of high molecular weight triglycerides i.e. most vegetable oils and animal fats, good fractionation is obtained for the majority of the pesticides. On the other hand, for fats and oils containing relatively high amounts of low molecular weight triglycerides, i.e. butter fat and palm kernel oil, none of the columns provided sufficient clean-up and cause interferences and system contamination, especially in the case of GC-MS/MS analysis. For the latter case, best results in terms of lipid removal and pesticide recovery were obtained on a set (2×300mmlength) of narrow bore (7.5mm ID) columns packed with 5µm PL Gel material. Column loadability is, however, much lower on that set of columns compared the other evaluated GPC columns, impairing overall method sensitivity.

  4. Detection of colchicine by means of LC-MS/MS after mistaking meadow saffron for bear's garlic.

    PubMed

    Wehner, Frank; Mußhoff, Frank; Schulz, Martin M; Martin, David D; Wehner, Heinz-Dieter

    2006-09-01

    The accidental ingestion of plant material containing colchicines is a rare cause of lethal poisoning. The death of a married couple who mistook colchicines for Bear's garlic (Allium ursinum) and prepared the latter as a salad is the tragic topic of this article. After discussing the specificity of the histological findings, a chemicotoxicological method using liquid chromatographic mass spectrometric (LC-MS/MS) is presented. Toxicological analyses using LC-MS/MS revealed colchicine concentrations between 36.6 ng/mL and 98.3 ng/mL in the heart blood and between 22.7 ng/mL and 78.4 ng/mL in the femoral blood of the victims.

  5. The analysis of linear and monomethylalkanes in exhaled breath samples by GC×GC-FID and GC-MS/MS.

    PubMed

    Hengerics Szabó, Alexandra; Podolec, Peter; Ferenczy, Viktória; Kubinec, Róbert; Blaško, Jaroslav; Soják, Ladislav; Górová, Renáta; Addová, Gabriela; Ostrovský, Ivan; Višňovský, Jozef; Bierhanzl, Václav; Čabala, Radomír; Amann, Anton

    2015-01-26

    A new arrangement of the INCAT (inside needle capillary adsorption trap) device with Carbopack X and Carboxen 1000 as sorbent materials was applied for sampling, preconcentration and injection of C6C19n-alkanes and their monomethyl analogs in exhaled breath samples. For the analysis both GC-MS/MS and GC×GC-FID techniques were used. Identification of the analytes was based on standards, measured retention indices and selective SRM transitions of the individual isomers. The GC-MS/MS detection limits were in the range from 2.1 pg for n-tetradecane to 86 pg for 5-methyloctadecane. The GC×GC-FID detection limits ranged from 19 pg for n-dodecane to 110 pg for 3-methyloctane.

  6. LC-MS/MS based identification of piperine production by endophytic Mycosphaerella sp. PF13 from Piper nigrum.

    PubMed

    Chithra, S; Jasim, B; Anisha, C; Mathew, Jyothis; Radhakrishnan, E K

    2014-05-01

    Piper nigrum is very remarkable for its medicinal properties due to the presence of metabolites like piperine. Emerging understanding on the biosynthetic potential of endophytic fungi suggests the possibility to have piperine producing fungi in P. nigrum. In the current study, endophytic fungi isolated from P. nigrum were screened for the presence of piperine by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This resulted in the identification of a Mycosphaerella sp. with the ability to produce piperine extracellularly. The biosynthesis of piperine (C17H19NO3) by the endophytic fungal isolate was confirmed by the presence of m/z 286.1 (M + H(+)) in the LC-MS/MS analysis using positive mode ionization. This was further supported by the presence of specific fragment ions with masses 135, 143, 171 and 201 formed due to the fragmentation of piperine present in the fungal extract.

  7. Quantitation of Buprenorphine, Norbuprenorphine, Buprenorphine Glucuronide, Norbuprenorphine Glucuronide, and Naloxone in Urine by LC-MS/MS.

    PubMed

    Marin, Stephanie J; McMillin, Gwendolyn A

    2016-01-01

    Buprenorphine is an opioid drug that has been used to treat opioid dependence on an outpatient basis, and is also prescribed for managing moderate to severe pain. Some formulations of buprenorphine also contain naloxone to discourage misuse. The major metabolite of buprenorphine is norbuprenorphine. Both compounds are pharmacologically active and both are extensively metabolized to their glucuronide conjugates, which are also active metabolites. Direct quantitation of the glucuronide conjugates in conjunction with free buprenorphine, norbuprenorphine, and naloxone in urine can distinguish compliance with prescribed therapy from specimen adulteration intended to mimic compliance with prescribed buprenorphine. This chapter quantitates buprenorphine, norbuprenorphine, their glucuronide conjugates and naloxone directly in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS). Urine is pretreated with formic acid and undergoes solid phase extraction (SPE) prior to analysis by LC-MS/MS.

  8. [Study on chemical constituents in stems of Nelumbo nucifera by UPLC-ESI/Q-TOF-MS/MS].

    PubMed

    Shan, Feng; Yuan, Yuan; Kang, Li-ping; Huang, Lu-qi

    2015-08-01

    This paper employed UPLC-Electrospray Ionization /Quadrupole-Time of Flight-Mass /Mass Spectrometry( UPLC-ESI/Q-TOF-MS/MS) to analyze the chemical constituents in the stems of Nelumbo nucifera. The stems of N. nucifera were extracted with 75% methanol, and we applied an Agilent Zorbax SB-Aq column (2.1 mm x 100 mm, 1.8 μm) to UPLC analysis with water methanol-water( containing 0.05% formic acid) in gradient as mobile phase. The eluates were then detected by ESI-Q-TOF-MS/MS. Results indicated that 22 benzylisoquinoline alkaloids were indendified. Among them, one alkaloid may be a new compound and a component was found in the Lotus for the first time. We fully identify the composition of the Lotus stems for the first time, Which could provides theoretical foundation for further study and utilization of the medicinal resources.

  9. Fast chiral chromatographic method development and validation for the quantitation of eszopiclone in human plasma using LC/MS/MS.

    PubMed

    Meng, Min; Rohde, Lisa; Cápka, Vladimír; Carter, Spencer J; Bennett, Patrick K

    2010-12-01

    Traditional chiral chromatographic separation method development is time consuming even for an experienced chromatographer. This paper describes the application of computer software ACD Lab to facilitate the development of chiral separation for the quantitation of eszopiclone using LC-MS/MS technology. Assisted by ACD/Chrom Manager and LC Simulator software, the optimal chiral chromatographic development was completed within hours. The baseline chiral separation was achieved with a total cycle time of 3 min. For sample extraction method development, a Waters Oasis Sorbent Selection Plate containing four different sorbents was utilized. Optimal conditions were determined using a single plate under various load, wash and elution conditions. This was followed by a GLP validation which demonstrated excellent intra- and inter-day accuracy and precision for the quantitation of eszopiclone in human plasma at 1.00-100 ng/mL range using LC/MS/MS technology. This method was utilized to support multiple clinic bioequivalence studies.

  10. Fragmentation pathways of drugs of abuse and their metabolites based on QTOF MS/MS and MS(E) accurate-mass spectra.

    PubMed

    Bijlsma, Lubertus; Sancho, Juan V; Hernández, Félix; Niessen, Wilfried M A

    2011-09-01

    A study of the fragmentation pathways of several classes of drugs of abuse (cannabinoids, ketamine, amphetamine and amphetamine-type stimulants (ATS), cocaine and opiates) and their related substances has been made. The knowledge of the fragmentation is highly useful for specific fragment selection or for recognition of related compounds when developing MS-based analytical methods for the trace-level determination of these compounds in complex matrices. In this work, accurate-mass spectra of selected compounds were obtained using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, performing both MS/MS and MS(E) experiments. As regards fragmentation behavior, the mass spectra of both approaches were quite similar and were useful to study the fragmentation of the drugs investigated. Accurate-mass spectra of 37 drugs of abuse and related compounds, including metabolites and deuterated analogues, were studied in this work, and structures of fragment ions were proposed. The accurate-mass data obtained allowed to confirm structures and fragmentation pathways previously proposed based on nominal mass measurements, although new insights and structure proposals were achieved in some particular cases, especially for amphetamine and ATS, 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH) and opiates.

  11. Branched perfluorooctane sulfonate isomer quantification and characterization in blood serum samples by HPLC/ESI-MS(/MS).

    PubMed

    Riddell, Nicole; Arsenault, Gilles; Benskin, Jonathan P; Chittim, Brock; Martin, Jonathan W; McAlees, Alan; McCrindle, Robert

    2009-10-15

    Perfluorooctane sulfonate (PFOS) is a global contaminant and is currently among the most prominent contaminants in human blood and wildlife samples. Although "total PFOS" (SigmaPFOS) analytical methods continue to be the most commonly used for quantification, recent analytical method developments have made it possible to resolve the various isomers of PFOS by HPLC-MS/MS. Characterized technical PFOS standards (i.e., containing a mixture of PFOS isomers) are now available that enable isomer specific quantification of PFOS, however the advantages of such an analysis have notyet been examined systematically. Herein, PFOS isomers have been individually quantified for the first time in real samples and the results are compared to a traditional SigmaPFOS method; the influence of analytical standards and isomer specific electrospray and MS/ MS behavior were also investigated. The two human serum standard reference materials chosen for analysis contained dramaticallydifferent PFOS isomer profiles (approximately 30-50% total branched isomers) emphasizing that isomer patterns should not be ignored and may provide useful information on exposure sources (i.e., direct exposure to PFOS vs indirect exposure from PFOS-precursors). Depending on the sample and the particular MS/MS transition chosen for SigmaPFOS analysis (i.e., 499-->80 or 499-->99), SigmaPFOS concentrations may be over- or underestimated compared to the isomer specific analysis. Differences in the extent of in-source fragmentation and MS/MS dissociation contributed to the systematic analytical bias. It was also shown that SigmaPFOS data are prone to interlaboratory variation due to various choices of PFOS standards and instrumental conditions used. In the future, for either SigmaPFOS or isomer specific PFOS analyses, we suggest that accuracy can be maximized and interlaboratory discrepancies minimized by using a common chemically pure technical PFOS standard characterized by 19F NMR.

  12. Structural modeling of protein-RNA complexes using crosslinking of segmentally isotope-labeled RNA and MS/MS.

    PubMed

    Dorn, Georg; Leitner, Alexander; Boudet, Julien; Campagne, Sébastien; von Schroetter, Christine; Moursy, Ahmed; Aebersold, Ruedi; Allain, Frédéric H-T

    2017-03-27

    Ribonucleoproteins (RNPs) are key regulators of cellular function. We established an efficient approach, crosslinking of segmentally isotope-labeled RNA and tandem mass spectrometry (CLIR-MS/MS), to localize protein-RNA interactions simultaneously at amino acid and nucleotide resolution. The approach was tested on polypyrimidine tract binding protein 1 and U1 small nuclear RNP. Our method provides distance restraints to support integrative atomic-scale structural modeling and to gain mechanistic insights into RNP-regulated processes.

  13. Wide-scope screening of pesticides in fruits and vegetables using information-dependent acquisition employing UHPLC-QTOF-MS and automated MS/MS library searching.

    PubMed

    Wang, Zhibin; Cao, Yanzhong; Ge, Na; Liu, Xiaomao; Chang, Qiaoying; Fan, Chunlin; Pang, Guo-Fang

    2016-11-01

    This paper presents an application of ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) for simultaneous screening and identification of 427 pesticides in fresh fruit and vegetable samples. Both full MS scan mode for quantification, and an artificial-intelligence-based product ion scan mode information-dependent acquisition (IDA) providing automatic MS to MS/MS switching of product ion spectra for identification, were conducted by one injection. A home-in collision-induced-dissociation all product ions accurate mass spectra library containing more than 1700 spectra was developed prior to actual application. Both qualitative and quantitative validations of the method were carried out. The result showed that 97.4 % of the pesticides had the screening detection limit (SDL) less than 50 μg kg(-1) and more than 86.7 % could be confirmed by accurate MS/MS spectra embodied in the home-made library. Meanwhile, calibration curves covering two orders of magnitude were performed, and they were linear over the concentration range studied for the selected matrices (from 5 to 500 μg kg(-1) for most of the pesticides). Recoveries between 80 and 110 % in four matrices (apple, orange, tomato, and spinach) at two spiked levels, 10 and 100 μg kg(-1), was 88.7 or 86.8 %. Furthermore, the overall relative standard deviation (RSD, n = 12) for 94.3 % of the pesticides in 10 μg kg(-1) and 98.1 % of the pesticides in 100 μg kg(-1) spiked levels was less than 20 %. In order to validate the suitability for routine analysis, the method was applied to 448 fruit and vegetable samples purchased in different local markets. The results show 83.3 % of the analyzed samples have positive findings (higher than the limits of identification and quantification), and 412 commodity-pesticide combinations are identified in our scope. The approach proved to be a cost-effective, time-saving and powerful strategy for routine large

  14. 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

  15. Analysis of dammar resin with MALDI-FT-ICR-MS and APCI-FT-ICR-MS.

    PubMed

    Vahur, Signe; Teearu, Anu; Haljasorg, Tõiv; Burk, Piia; Leito, Ivo; Kaljurand, Ivari

    2012-03-01

    Comprehensive analysis of high-resolution mass spectra of aged natural dammar resin obtained with Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS) using matrix-assisted laser desorption/ionization (MALDI) and atmospheric pressure chemical ionization (APCI) is presented. Dammar resin is one of the most important components of painting varnishes. Dammar resin is a terpenoid resin (dominated by triterpenoids) with intrinsically very complex composition. This complexity further increases with aging. Ten different solvents and two-component solvent mixtures were tested for sample preparation. The most suitable solvent mixtures for the MALDI-FT-ICR-MS analysis were dichloromethane-acetone and dichloromethane-ethanol. The obtained MALDI-FTMS mass spectrum contains nine clusters of peaks in the m/z range of 420-2200, and the obtained APCI-FTMS mass spectrum contains three clusters of peaks in the m/z range of 380-910. The peaks in the clusters correspond to the oxygenated derivatives of terpenoids differing by the number of C(15)H(24) units. The clusters, in turn, are composed of subclusters differing by the number of oxygen atoms in the molecules. Thorough analysis and identification of the components (or groups of components) by their accurate m/z ratios was carried out, and molecular formulas (elemental compositions) of all major peaks in the MALDI-FTMS and APCI-FTMS spectra were identified (and groups of possible isomeric compounds were proposed). In the MALDI-FTMS and APCI-FTMS mass spectrum, besides the oxidized C(30), triterpenoids also peaks corresponding to C(29) and C(31) derivatives of triterpenoids (demethylated and methylated, correspondingly) were detected. MALDI and APCI are complementary ionization sources for the analysis of natural dammar resin. In the MALDI source, preferably polar (extensively oxidized) components of the resin are ionized (mostly as Na(+) adducts), whereas in the APCI source, preferably nonpolar (hydrocarbon and

  16. Evaluation of several MS/MS search algorithms for analysis of spectra derived from electron transfer dissociation experiments.

    PubMed

    Kandasamy, Kumaran; Pandey, Akhilesh; Molina, Henrik

    2009-09-01

    Electron transfer dissociation (ETD) is increasingly becoming popular for high-throughput experiments especially in the identification of the labile post-translational modifications. Most search algorithms that are currently in use for querying MS/MS data against protein databases have been optimized on the basis of matching fragment ions derived from collision induced dissociation of peptides, which are dominated by b and y ions. However, electron transfer dissociation of peptides generates completely different types of fragments: c and z ions. The goal of our study was to test the ability of different search algorithms to handle data from this fragmentation method. We compared four MS/MS search algorithms (OMSSA, Mascot, Spectrum Mill, and X!Tandem) using approximately 170,000 spectra generated from a standard protein mix, as well as from complex proteomic samples which included a large number of phosphopeptides. Our analysis revealed (1) greater differences between algorithms than has been previously reported for CID data, (2) a significant charge state bias resulting in >60-fold difference in the numbers of matched doubly charged peptides, and (3) identification of 70% more peptides by the best performing algorithm than the algorithm identifying the least number of peptides. Our results indicate that the search engines for analyzing ETD derived MS/MS spectra are still in their early days and that multiple search engines could be used to reduce individual biases of algorithms.

  17. Analytics of the therapeutic peptide aviptadil by sheathless CE-MS and comparison with nanoRP-HPLC-MS.

    PubMed

    Gross, Peter C; Burkart, Sonja C; Müller, Rolf

    2014-01-01

    Purification and quality control of therapeutic peptides is often performed by one single method, RP-HPLC. As usage of an orthogonal technique is highly advisable for quality assurance, capillary electrophoresis (CE) employing a coated capillary coupled via a sheathless interface to a mass spectrometer was applied in parallel. The basic therapeutic peptide aviptadil served as a model substance to study the impurity profiles revealing 15 detectable impurities using CE-MS, two were detected by an appropriate nanoRP-HPLC-MS method. None of the impurities detected by CE were observed in LC and vice versa. The LOD in CE-MS was determined in the base peak electropherogram at ∼1fmol, a value 2500 times smaller than the LOD found in nanoRP-HPLC-MS (3pmol). In nanoRP-HPLC-MS only 0.2% of the extrapolated CE-MS signal for a 25ng aviptadil load was observed. We conclude that both, the LOD as well as the impurity profile of aviptadil, as analyzed by nanoRP-HPLC are influenced by both, the ligand-derivatized silica matrix and the flow-rate. Peptides may disappear completely and their variable emergence may lead to the determination of incorrect ratios as present in the sample.

  18. Fast targeted analysis of 132 acidic and neutral drugs and poisons in whole blood using LC-MS/MS.

    PubMed

    Di Rago, Matthew; Saar, Eva; Rodda, Luke N; Turfus, Sophie; Kotsos, Alex; Gerostamoulos, Dimitri; Drummer, Olaf H

    2014-10-01

    The aim of this study was to develop an LC-MS/MS based screening technique that covers a broad range of acidic and neutral drugs and poisons by combining a small sample volume and efficient extraction technique with simple automated data processing. After protein precipitation of 100μL of whole blood, 132 common acidic and neutral drugs and poisons including non-steroidal anti-inflammatory drugs, barbiturates, anticonvulsants, antidiabetics, muscle relaxants, diuretics and superwarfarin rodenticides (47 quantitated, 85 reported as detected) were separated using a Shimadzu Prominence HPLC system with a C18 separation column (Kinetex XB-C18, 4.6mm×150mm, 5μm), using gradient elution with a mobile phase of 25mM ammonium acetate buffer (pH 7.5)/acetonitrile. The drugs were detected using an ABSciex(®) API 2000 LC-MS/MS system (ESI+ and -, MRM mode, two transitions per analyte). The method was fully validated in accordance with international guidelines. Quantification data obtained using one-point calibration compared favorably to that using multiple calibrants. The presented LC-MS/MS assay has proven to be applicable for determination of the analytes in blood. The fast and reliable extraction method combined with automated processing gives the opportunity for high throughput and fast turnaround times for forensic and clinical toxicology.

  19. Improved liquid chromatography-MS/MS of heparan sulfate oligosaccharides via chip-based pulsed makeup flow.

    PubMed

    Huang, Yu; Shi, Xiaofeng; Yu, Xiang; Leymarie, Nancy; Staples, Gregory O; Yin, Hongfeng; Killeen, Kevin; Zaia, Joseph

    2011-11-01

    Microfluidic chip-based hydrophilic interaction chromatography (HILIC) is a useful separation system for liquid chromatography-mass spectrometry (LC-MS) in compositional profiling of heparan sulfate (HS) oligosaccharides; however, ions observed using HILIC LC-MS are low in charge. Tandem MS of HS oligosaccharide ions with low charge results in undesirable losses of SO(3) from precursor ions during collision induced dissociation. One solution is to add metal cations to stabilize sulfate groups. Another is to add a nonvolatile, polar compound such as sulfolane, a molecule known to supercharge proteins, to produce a similar effect for oligosaccharides. We demonstrate use of a novel pulsed makeup flow (MUF) HPLC-chip. The chip enables controlled application of additives during specified chromatographic time windows and thus minimizes the extent to which nonvolatile additives build up in the ion source. The pulsed MUF system was applied to LC-MS/MS of HS oligosaccharides. Metal cations and sulfolane were tested as additives. The most promising results were obtained for sulfolane, for which supercharging of the oligosaccharide ions increased their signal strengths relative to controls. Tandem MS of these supercharged precursor ions showed decreased abundances of product ions from sulfate losses yet more abundant product ions from backbone cleavages.

  20. Usage and limitations of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in clinical routine laboratories.

    PubMed

    Seger, Christoph

    2012-11-01

    Technical maturation of liquid chromatography tandem mass spectrometry (LC-MS/MS) brought this technology into most tertiary care clinical laboratories worldwide. It extended the technological armamentarium of clinical laboratories significantly, both in analytical and economical terms. Especially in therapeutic drug monitoring, endocrinology, and toxicology, it became an indispensable routine tool. Although well-designed LC-MS/MS assays generally outperform immunoassays because of increased accuracy, sensitivity, precision, and analytical multiplexing capability, they are not free from analytical problems. Besides limitations in selectivity due to the occurrence of "isobaric" interferences, unpredictable ion yield attenuations, known as "ion suppression effect," have to be considered. In addition, most LC-MS/MS methods used in clinical laboratories are still laboratory-developed tests ("in-house assays") operating on very heterogeneous instrument configurations. Consequently, assay heterogeneity and lack of traceability to reference procedures or materials may lead to an increased imprecision in proficiency testing as well as inaccurate result reporting if basic rules of assay validation and "post marketing" surveillance are violated.

  1. pyOpenMS: a Python-based interface to the OpenMS mass-spectrometry algorithm library.

    PubMed

    Röst, Hannes L; Schmitt, Uwe; Aebersold, Ruedi; Malmström, Lars

    2014-01-01

    pyOpenMS is an open-source, Python-based interface to the C++ OpenMS library, providing facile access to a feature-rich, open-source algorithm library for MS-based proteomics analysis. It contains Python bindings that allow raw access to the data structures and algorithms implemented in OpenMS, specifically those for file access (mzXML, mzML, TraML, mzIdentML among others), basic signal processing (smoothing, filtering, de-isotoping, and peak-picking) and complex data analysis (including label-free, SILAC, iTRAQ, and SWATH analysis tools). pyOpenMS thus allows fast prototyping and efficient workflow development in a fully interactive manner (using the interactive Python interpreter) and is also ideally suited for researchers not proficient in C++. In addition, our code to wrap a complex C++ library is completely open-source, allowing other projects to create similar bindings with ease. The pyOpenMS framework is freely available at https://pypi.python.org/pypi/pyopenms while the autowrap tool to create Cython code automatically is available at https://pypi.python.org/pypi/autowrap (both released under the 3-clause BSD licence).

  2. LC-MS/MS analysis of palytoxin analogues in blue humphead parrotfish Scarus ovifrons causing human poisoning in Japan.

    PubMed

    Suzuki, Toshiyuki; Watanabe, Ryuichi; Matsushima, Ryoji; Ishihara, Kenji; Uchida, Hajime; Kikutsugi, Saori; Harada, Tomoko; Nagai, Hiroshi; Adachi, Masao; Yasumoto, Takeshi; Murata, Masakazu

    2013-01-01

    Since 1953, a total of 27 human poisoning cases caused by the consumption of blue humphead parrotfish, Scarus ovifrons, have been reported in Japan. Characteristic symptoms are severe muscle pain associated with rhabdomyolysis. Although it is believed that palytoxin, which is one of the most potent non-protein marine biotoxins, is the most likely causative toxin in blue humphead parrotfish poisoning, palytoxin has not been proven conclusively as the causative toxin because of lack of a reliable and sensitive analytical method for palytoxin. In 2011, human poisoning cases caused by the consumption of blue humphead parrotfish occurred in Miyazaki and Tokyo. In our present study, an LC-MS/MS method for palytoxin and its analogues in the blue humphead parrotfish samples causing the human poisoning cases in 2011 was developed and the samples were analysed by using the newly developed LC-MS/MS method. Palytoxin and its analogues were not detected in the samples from the food poisoning cases. The LC-MS/MS findings therefore do not support the recently accepted hypothesis that palytoxin is the causative agent in blue humphead parrotfish poisoning in Japan.

  3. LC-ESI-MS/MS analysis and pharmacokinetics of heterophyllin B, a cyclic octapeptide from Pseudostellaria heterophylla in rat plasma.

    PubMed

    Zhao, Wai-Ou; Pang, Li; Dong, Ning; Yang, Shu

    2015-11-01

    Heterophyllin B (HB) is a cyclic octapeptide isolated from Pseudostellaria heterophylla. HB is used as the quality control index for evaluating P. heterophylla in the Chinese Pharmacopoeia. A rapid and sensitive LC-ESI-MS/MS method was developed and validated for the analysis of HB in rat plasma. Sample preparation consisted of a solid-phase extraction step for the removal of interference and preconcentration of the target analyte HB and the internal standard N-acetylcysteine before chromatographic analysis by MS/MS detection. The separation of HB and N-acetylcysteine was performed using a Hypersil GOLD™ C18 column and a mixture of methanol-water (60:40, v/v) containing 10 mmol/L ammonium formate and 0.1% formic acid as the mobile phase. The determination step was optimized in the selected reaction monitoring mode for the highly selective and sensitive quantitation of HB in rat plasma. Intra- and inter-assay precision (as relative standard deviation) was ≤9.1%, and accuracy was between 92.6 and 102.7%. The validated method was successfully applied to quantify HB concentrations up to 7 h after tail intravenous injections of 2.08, 4.16 and 8.32 mg/kg HB in rats. The LC-MS/MS method identified the relevant pharmacokinetic parameters of HB and its studied analog.

  4. A Fast One Step Extraction and UPLC-MS/MS Analysis for E2/D2 Series Prostaglandins and Isoprostanes

    PubMed Central

    Brose, Stephen A.; Baker, Andrew G.; Golovko, Mikhail Y.

    2013-01-01

    Prostaglandins (PG) and isoprostanes (iso-PG) may be derived through cyclooxygenase or free radical pathways and are important signaling molecules that are also robust biomarkers of oxidative stress. Their quantification is important for understanding many biological processes where PG, iso-PG, or oxidative stress are involved. One of the common methods for PG and iso-PG quantifications is LC-MS/MS that allows a highly selective, sensitive, simultaneous analysis for prostanoids without derivatization. However, the currently used LC-MS/MS methods require a multi-step extraction and a long (within an hour) LC separation to achieve simultaneous separation and analysis of the major iso-PG. The developed and validated for brain tissue analysis one-step extraction protocol and UPLC-MS/MS method significantly increases the recovery of the PG extraction up to 95%, and allows for a much faster (within 4 min) major iso-PGE2 and -PGD2 separation with 5 times narrower chromatographic peaks as compared to previously used methods. In addition, it decreases the time and cost of analysis due to one-step extraction approach performed in disposable centrifuge tubes. All together, this significantly increases the sensitivity, and the time and cost efficiency of the PG and iso-PG analysis. PMID:23400687

  5. Quality changes during storage of cooked and sliced meat products measured with PTR-MS and HS-GC-MS.

    PubMed

    Holm, E S; Adamsen, A P S; Feilberg, A; Schäfer, A; Løkke, M M; Petersen, M A

    2013-10-01

    The changes in the VOC composition of industrially produced saveloy were measured with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) and HeadSpace Gas chromatography-mass spectrometry (HS-GC-MS) during a six weeks storage period. A decrease in the volatile organic compounds contributing to the fresh aroma of saveloy was the main change observed with both PTR-MS and HS-GC-MS. Samples of four other types of cooked and sliced meat product were measured with PTR-MS in the middle and at the end of the four week shelf-life period. These measurements showed an increase in m/z 69, 71, 87 and 89 for the pork loin and in m/z 61 for the herbal saveloy samples. These ions were assigned to the microbial spoilage markers: acetic acid, 2- and 3-methylbutanol, 2- and 3-methylbutanal, diacetyl and acetoin. Overall, this study shows that PTR-MS has potential for quality control of cooked and sliced meat products.

  6. Highly sensitive quantification of serum malonate, a possible marker for de novo lipogenesis, by LC-ESI-MS/MS.

    PubMed

    Honda, Akira; Yamashita, Kouwa; Ikegami, Tadashi; Hara, Takashi; Miyazaki, Teruo; Hirayama, Takeshi; Numazawa, Mitsuteru; Matsuzaki, Yasushi

    2009-10-01

    We describe a new sensitive and specific method for the quantification of serum malonate (malonic acid, MA), which could be a new biomarker for de novo lipogenesis (fatty acid synthesis). This method is based upon a stable isotope-dilution technique using LC-MS/MS. MA from 50 microl of serum was derivatized into di-(1-methyl-3-piperidinyl)malonate (DMP-MA) and quantified by LC-MS/MS using the positive electrospray ionization mode. The detection limit of the DMP-MA was approximately 4.8 fmol (500 fg) (signal-to-noise ratio = 10), which was more than 100 times more sensitive compared with that of MA by LC-MS/MS using the negative electrospray ionization mode. The relative standard deviations between sample preparations and measurements made using the present method were 4.4% and 3.2%, respectively, by one-way ANOVA. Recovery experiments were performed using 50 microl aliquots of normal human serum spiked with 9.6 pmol (1 ng) to 28.8 pmol (3 ng) of MA and were validated by orthogonal regression analysis. The results showed that the estimated amount within a 95% confidence limit was 14.1 +/- 1.1 pmol, which was in complete agreement with the observed X(0) = 15.0 +/- 0.6 pmol, with a mean recovery of 96.0%. This method provides reliable and reproducible results for the quantification of MA in human serum.

  7. An integrated strategy for establishment of metabolite profile of endogenous lysoglycerophospholipids by two LC-MS/MS platforms.

    PubMed

    Chen, Guiying; Song, Chengwu; Jin, Shuna; Li, Sen; Zhang, Yang; Huang, Rongzeng; Feng, Yulin; Xu, Yong; Xiang, Yi; Jiang, Hongliang

    2017-01-01

    The methods for detecting endogenous phospholipids (PL) are focused on the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Since the structural relation and similar core structure of glycerophospholipids results in a common and predictable mass spectrometric fragmentation behavior, in the present study, six classes of lysoglycerophospholipid (Lyso-PL) were subjected to a predict-verify approach by multiple reaction monitoring (MRM) mode based on liquid chromatography-quadrupole linear ion trap mass spectrometry (LC-QTRAP-MS/MS) complemented with liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOF-MS/MS) in biological serum samples. A targeted metabolite profile of Lyso-PL was established and represented in the form of a LC-QTRAP-MRM analysis. There were total of 96 Lyso-PL molecular species, consisting of 317 regioisomers detected in serum of human and four rodent species. In addition, the metabolite profile was successfully applied to the analysis of qualitative distribution of Lyso-PLs in serum of human and four rodent species. We believe that this improvement in the method for qualitative analysis of endogenous Lyso-PLs should greatly contribute to identifying the role of lipid molecular species in biological systems. Also, the integrated strategy for establishment of metabolite profile can be applied to targeted qualitative analysis of other endogenous metabolites which occur in a high individual number but sharing either structural similarities or similar functional groups.

  8. Simultaneous determination of selected endocrine disrupter compounds in wastewater samples in ultra trace levels using HPLC-ES-MS/MS.

    PubMed

    Komesli, Okan Tarık; Bakırdere, Sezgin; Bayören, Ceren; Gökçay, Celal Ferdi

    2012-08-01

    An analytical procedure for the simultaneous determination of six selected endocrine disrupter compounds (EDCs: diltiazem, progesterone, benzyl butyl phthalate (BBP), estrone, carbamazepine (Cbz), acetaminophen) was developed by liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ES-MS/MS). All of the parameters for HPLC and ES-MS/MS systems including mobile phase composition, flow rate, and sample injection volume were optimized to obtain not only the best separation of species interested but also low detection limits. Reverse phase chromatography coupled to ES-MS/MS was used for the separation and detection of EDCs. Formic acid (0.10% ) and 5.0 mM ammonium formate were selected as mobile phase composition in gradient elution. Detection limits for diltiazem, progesterone, BBP, estrone, Cbz, and acetaminophen were found to be 0.13, 0.12, 0.04, 0.13, 0.12, and 0.05 ng/mL, respectively. Influent and effluents from three different wastewater treatment plants located in Ankara, i.e., rotating flat-sheet membrane unit, pilot type flat-sheet membrane unit located at METU Campus and samples from Ankara central wastewater treatment plant were analyzed for their EDCs contents under the optimum conditions.

  9. EPA LABORATORIES IMPLEMENT EMS PROGRAM

    EPA Science Inventory

    This paper highlights the breadth and magnitude of carrying out an effective Environmental Management System (EMS) program at the U.S. EPA's research and development laboratories. Federal research laboratories have unique operating challenges compared to more centralized industr...

  10. Analysis and Speciation of Lanthanoides by ICP-MS

    NASA Astrophysics Data System (ADS)

    Telgmann, Lena; Lindner, Uwe; Lingott, Jana; Jakubowski, Norbert

    2016-11-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is based on formation of positively charged atomic ions in a high-frequency inductively coupled Argon plasma at atmospheric pressure. The ions are extracted and transferred from the plasma source into a mass analyzer operated at high vacuum via an interface equipped with a sampling and a skimmer cone. The ions are separated in the mass analyzer according to their charge to mass ratio. The ions are converted at a conversion dynode and are detected by use of a secondary electron multiplier or a Faraday cup. From an analytical point of view, ICP-MS is a well-established method for multi-elemental analysis in particular for elements at trace- and ultra-trace levels. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional analytical techniques, and relative limits of detection (LODs) in the low pg g-1 range and absolute LODs down to the attomol range. For these applications, ICP-MS excels by a high sensitivity which is independent of the molecular structure and a wide linear dynamic range. It has found acceptance in various application areas and during the last decade ICP-MS is also more and more applied for detection of rare earth elements particularly in the life sciences. Due to the fact that all molecules introduced into the high temperature of the plasma in the ion source were completely dissociated and broken down into atoms, which are subsequently ionized, all elemental species information is completely lost. However, if the different species are separated before they enter the plasma by using adequate fractionation or separation techniques, then ICP-MS can be used as a very sensitive element-specific detector. We will discuss this feature of ICP-MS in this chapter in more detail at hand of the speciation of gadolinium-containing contrast agents.

  11. Melatonin acts as antioxidant and improves sleep in MS patients.

    PubMed

    Adamczyk-Sowa, Monika; Pierzchala, Krystyna; Sowa, Pawel; Mucha, Sebastian; Sadowska-Bartosz, Izabela; Adamczyk, Jowita; Hartel, Marcin

    2014-08-01

    The relationship between the prevalence of multiple sclerosis (MS) and sunlight's ultraviolet radiation was proved. Oxidative stress plays a role in the pathogenic traits of MS. Melatonin possesses antioxidative properties and regulates circadian rhythms. Sleep disturbances in MS patients are common and contribute to daytime fatigue. The aim of study was to evaluate 5 mg daily melatonin supplementation over 90 days on serum total oxidant status (TOS), total antioxidant capacity (TAC) and its influence on sleep quality and depression level of MS patients. A case-control prospective study was performed on 102 MS patients and 20 controls matched for age and sex. The Kurtzke's Expanded Disability Status Scale, magnetic resonance imaging examinations, Athens Insomnia Scale (AIS), Beck Depression Inventory questionnaires were completed. Serum TOS and TAC levels were measured. We observed higher serum levels of TOS in all MS groups, while after melatonin treatment the TOS levels significantly decreased. The TAC level was significantly lower only in mitoxantrone-treated group and it increased after melatonin supplementation. A strong positive correlation between T1Gd(+) number lesions and TAC level in interferon-beta-1A group was observed. AIS group mean score above 6 defining insomnia were observed in interferon-beta-1B-group, glatiramer acetate-group and mitoxantrone-group: 6.62 ± 2.88, 8.45 ± 2.07, 11.1 ± 3.25, respectively. After melatonin treatment the AIS mean scores decrease in glatiramer acetate-group and mitoxantrone-group achieving 5.25 ± 1.14 and 7.08 ± 2.39, respectively (p < 0.05). Finding from our study suggest that melatonin can act as an antioxidant and improves reduced sleep quality in MS patients.

  12. MS2 bacteriophage reduction and microbial communities in biosand filters.

    PubMed

    Wang, Hanting; Narihiro, Takashi; Straub, Anthony P; Pugh, Charles R; Tamaki, Hideyuki; Moor, Johnathan F; Bradley, Ian M; Kamagata, Yoichi; Liu, Wen-Tso; Nguyen, Thanh H

    2014-06-17

    This study evaluated the role of physical and biological filter characteristics on the reduction of MS2 bacteriophage in biosand filters (BSFs). Three full-scale concrete Version 10 BSFs, each with a 55 cm sand media depth and a 12 L charge volume, reached 4 log10 reduction of MS2 within 43 days of operation. A consistently high reduction of MS2 between 4 log10 and 7 log10 was demonstrated for up to 294 days. Further examining one of the filters revealed that an average of 2.8 log10 reduction of MS2 was achieved within the first 5 cm of the filter, and cumulative virus reduction reached an average of 5.6 log10 after 240 days. Core sand samples from this filter were taken for protein, carbohydrate, and genomic extraction. Higher reduction of MS2 in the top 5 cm of the sand media (0.56 log10 reduction per cm vs 0.06 log10 reduction per cm for the rest of the filter depth) coincided with greater diversity of microbial communities and increased concentrations of carbohydrates. In the upper layers, "Candidatus Nitrosopumilus maritimus" and "Ca. Nitrospira defluvii" were found as dominant populations, while significant amounts of Thiobacillus-related OTUs were detected in the lower layers. Proteolytic bacterial populations such as the classes Sphingobacteria and Clostridia were observed over the entire filter depth. Thus, this study provides the first insight into microbial community structures that may play a role in MS2 reduction in BSF ecosystems. Overall, besides media ripening and physical reduction mechanisms such as filter depth and long residence time (45 min vs 24 ± 8.5 h), the establishment of chemolithotrophs and proteolytic bacteria could greatly enhance the reduction of MS2.

  13. Determination of erythromycin and tylosin residues in honey by LC/MS/MS.

    PubMed

    Granja, Rodrigo; Niño, Alfredo Montes; Zucchetti, Roberto; Niño, Rosario Montes; Patel, Raj; Salerno, Alessandro Gonzalez

    2009-01-01

    Antibiotics are used in apiculture to protect bees against a variety of brood diseases. As a result of the development of resistance to oxytetracycline, erythromycin and tylosin are increasingly used for the prevention and treatment of these diseases. Therefore, Brazilian authorities have added these antibiotics to the National Regulatory Monitoring Program for the control of residues in honey. An analytical method has been developed for the determination of residues of erythromycin and tylosin in honey. The procedure involves solid-phase extraction of diluted honey samples with Bond Elut cartridges, followed by LC/MS with electrospray positive ionization in the multiple reaction monitoring mode. Two characteristic transitions were monitored for both drugs. Average analyte recoveries of erythromycin and tylosin ranged from 99 to 109% from sets of replicate honey samples fortified with drug concentrations of 5, 10, 15, and 20 microg/kg. The method decision limits were determined to be 1.27 and 0.59 microg/kg for erythromycin and tylosin, respectively. The detection capabilities were 5 and 5.2 microg/kg for erythromycin and tylosin, respectively.

  14. Chlorination of benzothiazoles and benzotriazoles and transformation products identification by LC-HR-MS/MS.

    PubMed

    Nika, Maria-Christina; Bletsou, Anna A; Koumaki, Elena; Noutsopoulos, Constantinos; Mamais, Daniel; Stasinakis, Athanasios S; Thomaidis, Nikolaos S

    2017-02-05

    The fate of four benzotriazoles [1-H-benzotriazole (1-H-BTRi), tolyltriazole (TTRi), xylyltriazole (XTRi) and 1-hydroxy-benzotriazole (1-OH-BTRi)] and three benzothiazoles [benzothiazole (BTH), 2-hydroxy-benzothiazole (2-OH-BTH) and 2-amino-benzothiazole (2-amino-BTH)], during chlorination batch experiments was investigated. In the first step, their degradation under different experimental conditions (applied molar ratio of NaOCl and the target contaminant (m.r.), reaction's contact time, pH value of the reaction's solution and the influence of total suspended solids (TSS) presence) was investigated and their removal kinetics parameters (kobs and t1/2) were determined. In the second step, LC-QTOFMS/MS was used for the detection and identification of transformation products (TPs) formed during chlorination, through the application of suspect and non-target screening approaches. Four and five TPs of XTRi and 2-amino-BTH, respectively, were detected and tentatively identified, while 1-H-BTRi was proven to be formed by the chlorination of 1-OH-BTRi. Moreover, since the identified TPs were also detected in spiked wastewater samples, after lab-scale chlorination experiments, toxicity assessment was carried out by ECOSAR calculations for the environmental relevance of their occurrence. The proposed chlorinated TPs were proven to be more toxic than their parent compounds.

  15. Determination of piracetam in rat plasma by LC-MS/MS and its application to pharmacokinetics.

    PubMed

    Wang, Xianqin; Zhu, Jiayin; Xu, Renai; Yang, Xuezhi; Wu, Haiya; Lin, Dan; Ye, Faqing; Hu, Lufeng

    2010-10-01

    A sensitive and selective liquid chromatography-tandem mass spectrometry method for the determination of piracetam in rat plasma was developed and validated over the concentration range of 0.1-20 µg/mL. After addition of oxiracetam as internal standard, a simplified protein precipitation with trichloroacetic acid (5%) was employed for the sample preparation. Chromatographic separation was performed by a Zorbax SB-Aq column (150 × 2.1 mm, 3.5 µm). The mobile phase was acetonitrile-1% formic acid in water (10:90 v/v) delivered at a flow rate of 0.3 mL/min. The MS data acquisition was accomplished in multiple reaction monitoring mode with a positive electrospray ionization interface. The lower limit of quantification was 0.1 µg/mL. For inter-day and intra-day tests, the precision (RSD) for the entire validation was less than 9%, and the accuracy was within the 94.6-103.2% range. The developed method was successfully applied to pharmacokinetic studies of piracetam in rats following single oral administration dose of 50 mg/kg.

  16. HPLC-MS/MS methods for the determination of 52 perfluoroalkyl and polyfluoroalkyl substances in aqueous samples.

    PubMed

    Gremmel, Christoph; Frömel, Tobias; Knepper, Thomas P

    2017-02-01

    Two quantitative methods using high-performance liquid chromatography (HPLC) combined with triple quadrupole tandem mass spectrometry (MS/MS) were developed to determine perfluoroalkyl and polyfluoroalkyl substances (PFASs) in aqueous samples. The first HPLC-MS/MS method was applied to 47 PFASs of 12 different substance classes with acidic characteristics such as perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), as well as precursor substances and biotransformation intermediates (e.g., unsaturated fluorotelomer carboxylic acids). In addition, 25 (13)C-, (18)O-, and (2)H-labeled PFASs were used as internal standards in this method. The second HPLC-MS/MS method was applied to fluorotelomer alcohols (FTOHs) and perfluorooctane sulfonamidoethanols as these compounds have physicochemical properties different from those of the previous ones. Accuracy between 82% and 110% and a standard deviation in the range from 2% to 22% depending on the substances were determined during the evaluation of repeatability and precision. The method quantification limit after solid-phase extraction ranged from 0.3 to 199 ng/L depending on the analyte and matrix. The HPLC-MS/MS methods developed were suitable for the determination of PFASs in aqueous samples (e.g., wastewater treatment plant effluents or influents after solid-phase extraction). These methods will be helpful in monitoring campaigns to evaluate the relevance of precursor substances as indirect sources of perfluorinated substances in the environment. In one exemplary application in an industrial wastewater treatment plant, FTOHs were found to be the major substance class in the influent; in particular, 6:2-FTOH was the predominant compound in the industrial samples and accounted for 74% of the total PFAS concentration. The increase in the concentration of the transformation products of FTOHs in the corresponding effluent, such as fluorotelomer carboxylic acids, unsaturated fluorotelomer

  17. High-Throughput Analytical Techniques for the Determination of the Residues of 653 Multiclass Pesticides and Chemical Pollutants in Tea, Part VII: A GC-MS, GC-MS/MS, and LC-MS/MS Study of the Degradation Profiles of Pesticide Residues in Green Tea.

    PubMed

    Chang, Qiao-Ying; Pang, Guo-Fang; Fan, Chun-Lin; Chen, Hui; Yang, Fang; Li, Jie; Wen, Bi-Fang

    2016-11-01

    GC-MS, GC-tandem MS (MS/MS), and LC-MS/MS were used to mathematically define the degradation profiles of pesticide residues in two field trials. Nineteen pesticides were studied in the first field trial and 11 in the second. The results of the field trials demonstrated that the degradation profiles of pesticide residues in green tea can be described with power functions to successfully estimate the amount of time, following pesticide application, pesticide residues appearing in tea in concentrations at and/or above the maximum residue limit (MRL) decrease to concentrations below the MRL. Stability tests on green tea samples stored at room temperature were conducted to determine whether pesticide-incurred green tea samples prepared according to the method used in the field trials would be suitable for the preparation of reference standards for laboratory-proficiency testing trials. This paper reports the results of a GC-MS, GC-MS/MS, and LC-MS/MS study, as well as the suitability of the samples prepared under these conditions for use as pesticide reference standards in tea analysis.

  18. Dinosaur: A Refined Open-Source Peptide MS Feature Detector

    PubMed Central

    2016-01-01

    In bottom-up mass spectrometry (MS)-based proteomics, peptide isotopic and chromatographic traces (features) are frequently used for label-free quantification in data-dependent acquisition MS but can also be used for the improved identification of chimeric spectra or sample complexity characterization. Feature detection is difficult because of the high complexity of MS proteomics data from biological samples, which frequently causes features to intermingle. In addition, existing feature detection algorithms commonly suffer from compatibility issues, long computation times, or poor performance on high-resolution data. Because of these limitations, we developed a new tool, Dinosaur, with increased speed and versatility. Dinosaur has the functionality to sample algorithm computations through quality-control plots, which we call a plot trail. From the evaluation of this plot trail, we introduce several algorithmic improvements to further improve the robustness and performance of Dinosaur, with the detection of features for 98% of MS/MS identifications in a benchmark data set, and no other algorithm tested in this study passed 96% feature detection. We finally used Dinosaur to reimplement a published workflow for peptide identification in chimeric spectra, increasing chimeric identification from 26% to 32% over the standard workflow. Dinosaur is operating-system-independent and is freely available as open source on https://github.com/fickludd/dinosaur. PMID:27224449

  19. SPR-MS: from identifying adsorbed molecules to image tissues

    NASA Astrophysics Data System (ADS)

    Masson, Jean-François; Breault-Turcot, Julien; Forest, Simon; Chaurand, Pierre

    2015-03-01

    Surface plasmon resonance (SPR) sensors have become valuable analytical sensors for biomolecule detection. While SPR is heralded with high sensitivity, label-free and real-time detection, nonspecific adsorption and detection of ultralow concentrations remain issues. Nonspecific adsorption can be minimized using adequate surface chemistry. For example, we have employed peptide monolayers to reduce nonspecific adsorption of crude serum or cell lysate. It is important to uncover the nature of molecules nonspecifically adsorbing to surfaces in these biofluids, to further improve understanding of the nonspecific adsorption processes. Mass spectrometry (MS) provides a complementary tool to SPR to identify biomolecule adsorbed to surface. Trypsic digestion of the proteins adsorbed to surfaces led to identification of characteristic peptides from the proteins involved in nonspecific adsorption. Nonspecific adsorption in crude cell lysate results mainly from lipids, as confirmed with SPR and MS but proteins were observed on some surfaces. In another application of SPR and MS, imaging SPR can be used in combination to imaging MS to image tissue sections. Thin sections of mouse liver were inserted in the fluidic chamber of a SPRi instrument and proteins were transferred to the SPRi chip. The SPR chip was then imaged using MALDI imaging MS to identify the biomolecules that were transferred to the SPRi chip.

  20. HPTLC-MS Coupling: New Dimension of HPTLC

    NASA Astrophysics Data System (ADS)

    Gupta, Ajai Prakash; Gupta, Suphla

    The direct coupling of TLC/HPTLC with mass spectrometry (MS) is of particular interest because of the later's high sensitivity, rapid analysis, and ability to aid structural characterization. The conventional ionization method requires heating of the analyte and was suitable only for the analyses of volatile and thermally stable compounds. In contrast, desorption/ionization (DI) techniques, such as fast atom bombardment (FAB), plasma desorption, laser desorption, and matrix-assisted laser desorption/ionization (MALDI) methods, appear to be better for directly characterizing nonvolatile and thermally labile chemical or biochemical compounds separated by HPTLC. HPTLC-MS is cost-effective because the chromatographic run is decoupled with the detection step. Van Berkel and co-workers introduced a novel TLC-ESI-MS, a surface sampling probe-to-TLC/HPTLC plate liquid microjunction, and a self-aspirating ES emitter for the direct detection of small organic compounds. Luftmann developed a plunger-based extraction device for TLC/HPTLC ESI-MS and used a direct electrospray probe to generate analyte ions directly from the end of a TLC plate. Recently, Van Berkel's group applied desorption electrospray ionization (DESI). Cooks et al. introduced the analysis of analytes on solids for coupling TLC with MS. Due to the great understanding of the subject, thin layer chromatography/high-performance thin-layer chromatography can be used interchangeably for methods developed in the twenty-first century.

  1. Laser desorption VUV postionization MS imaging of a cocultured biofilm.

    PubMed

    Bhardwaj, Chhavi; Moore, Jerry F; Cui, Yang; Gasper, Gerald L; Bernstein, Hans C; Carlson, Ross P; Hanley, Luke

    2013-09-01

    Laser desorption postionization mass spectrometry (LDPI-MS) imaging is demonstrated with a 10.5 eV photon energy source for analysis and imaging of small endogenous molecules within intact biofilms. Biofilm consortia comprised of a synthetic Escherichia coli K12 coculture engineered for syntrophic metabolite exchange are grown on membranes and then used to test LDPI-MS analysis and imaging. Both E. coli strains displayed many similar peaks in LDPI-MS up to m/z 650, although some observed differences in peak intensities were consistent with the appearance of byproducts preferentially expressed by one strain. The relatively low mass resolution and accuracy of this specific LDPI-MS instrument prevented definitive assignment of species to peaks, but strategies are discussed to overcome this shortcoming. The results are also discussed in terms of desorption and ionization issues related to the use of 10.5 eV single-photon ionization, with control experiments providing additional mechanistic information. Finally, 10.5 eV LDPI-MS was able to collect ion images from intact, electrically insulating biofilms at ~100 μm spatial resolution. Spatial resolution of ~20 μm was possible, although a relatively long acquisition time resulted from the 10 Hz repetition rate of the single-photon ionization source.

  2. Two-dimensional HPLC coupled to ICP-MS and electrospray ionisation (ESI)-MS/MS for investigating the bioavailability in vitro of arsenic species from edible seaweed.

    PubMed

    Garcia-Sartal, Cristina; Taebunpakul, Sutthinun; Stokes, Emma; Barciela-Alonso, María del Carmen; Bermejo-Barrera, Pilar; Goenaga-Infante, Heidi

    2012-04-01

    Edible seaweed consumption is a route of exposure to arsenic. However, little attention has been paid to estimate the bioaccessibility and/or bioavailability of arsenosugars in edible seaweed and their possible degradation products during gastrointestinal digestion. This work presents first use of combined inductively coupled plasma mass spectroscopy (ICP-MS) with electrospray ionization tandem mass spectrometry (ESI-MS/MS) with two-dimensional HPLC (size exclusion followed by anion exchange) to compare the qualitative and quantitative arsenosugars speciation of different edible seaweed with that of their bioavailable fraction as obtained using an in vitro gastrointestinal digestion procedure. Optimal extraction conditions for As species from four seaweed namely kombu, wakame, nori and sea lettuce were selected as a compromise between As extraction efficiency and preservation of compound identity. For most investigated samples, the use of ammonium acetate buffer as extractant and 1 h sonication in a water bath followed by HPLC-ICP-MS resulted in 40-61% of the total As to be found in the buffered aqueous extract, of which 86-110% was present as arsenosugars (glycerol sugar, phosphate sugar and sulfonate sugar for wakame and kombu and glycerol sugar and phosphate sugar for nori). The exception was sea lettuce, for which the arsenosugar fraction (glycerol sugar, phosphate sugar) only comprised 44% of the total extracted As. Interestingly, the ratio of arsenobetaine and dimethylarsinic acid to arsenosugars in sea lettuce extracts seemed higher than that for the rest of investigated samples. After in vitro gastrointestinal digestion, approximately 11-16% of the total As in the solid sample was found in the dialyzates with arsenosugars comprising 93-120% and 41% of the dialyzable As fraction for kombu, wakame, nori and sea lettuce, respectively. Moreover, the relative As species distribution in seaweed-buffered extracts and dialyzates was found to be very similar

  3. A Fast and Effective Microfluidic Spraying-Plunging Method for High-Resolution Single-Particle Cryo-EM.

    PubMed

    Feng, Xiangsong; Fu, Ziao; Kaledhonkar, Sandip; Jia, Yuan; Shah, Binita; Jin, Amy; Liu, Zheng; Sun, Ming; Chen, Bo; Grassucci, Robert A; Ren, Yukun; Jiang, Hongyuan; Frank, Joachim; Lin, Qiao

    2017-03-06

    We describe a spraying-plunging method for preparing cryoelectron microscopy (cryo-EM) grids with vitreous ice of controllable, highly consistent thickness using a microfluidic device. The new polydimethylsiloxane (PDMS)-based sprayer was tested with apoferritin. We demonstrate that the structure can be solved to high resolution with this method of sample preparation. Besides replacing the conventional pipetting-blotting-plunging method, one of many potential applications of the new sprayer is in time-resolved cryo-EM, as part of a PDMS-based microfluidic reaction channel to study short-lived intermediates on the timescale of 10-1,000 ms.

  4. 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.

  5. Marker peptide selection for the determination of hazelnut by LC-MS/MS and occurrence in other nuts.

    PubMed

    Ansari, Parisa; Stoppacher, Norbert; Baumgartner, Sabine

    2012-03-01

    The aim of this work was identifying and selecting hazelnut marker peptides and subsequently developing a complementary method of common immunoassay for the detection of hazelnut. For this purpose, at first, an in silico digestion of three major hazelnut allergens (Cor a 8, Cor a 9 and Cor a 11) was performed to get information about expected peptides. After extraction and trypsin digestion of hazelnut proteins, the samples were measured with tandem mass spectrometry (MS/MS) by direct infusion, which led to identification of 14 peptides. Eight of them with the highest MS signal were synthesized and used as standards for developing a liquid chromatography (LC)-MS/MS method in selected reaction monitoring (SRM) mode. Since almost all food allergens derived from nuts belong to the seed storage protein family and have homologue structure, a Basic Local Alignment Search Tool (BLAST) search was performed to identify the hazelnut specificity of the developed method. According to BLAST, only one peptide occurs in three other nuts, and the remaining seven selected peptides are hazelnut specific. Additionally to hazelnut, the eight other listed nuts in Directive 2003/89/EC as allergen were extracted, digested and measured with the developed method to prove the BLAST results. The analytical data confirmed that six peptides are hazelnut specific, on the contrary to anti-hazelnut antibodies, which showed cross-reactivities to all other nut extracts. Comparing these results, it could be shown that with this LC-MS/MS method in SRM mode, the specific detection of hazelnut is possible.

  6. Lumpy - an interactive Lumped Parameter Modeling code based on MS Access and MS Excel.

    NASA Astrophysics Data System (ADS)

    Suckow, A.

    2012-04-01

    Several tracers for dating groundwater (18O/2H, 3H, CFCs, SF6, 85Kr) need lumped parameter modeling (LPM) to convert measured values into numbers with unit time. Other tracers (T/3He, 39Ar, 14C, 81Kr) allow the computation of apparent ages with a mathematical formula using radioactive decay without defining the age mixture that any groundwater sample represents. Also interpretation of the latter profits significantly from LPM tools that allow forward modeling of input time series to measurable output values assuming different age distributions and mixtures in the sample. This talk presents a Lumped Parameter Modeling code, Lumpy, combining up to two LPMs in parallel. The code is standalone and freeware. It is based on MS Access and Access Basic (AB) and allows using any number of measurements for both input time series and output measurements, with any, not necessarily constant, time resolution. Several tracers, also comprising very different timescales like e.g. the combination of 18O, CFCs and 14C, can be modeled, displayed and fitted simultaneously. Lumpy allows for each of the two parallel models the choice of the following age distributions: Exponential Piston flow Model (EPM), Linear Piston flow Model (LPM), Dispersion Model (DM), Piston flow Model (PM) and Gamma Model (GM). Concerning input functions, Lumpy allows delaying (passage through the unsaturated zone) shifting by a constant value (converting 18O data from a GNIP station to a different altitude), multiplying by a constant value (geochemical reduction of initial 14C) and the definition of a constant input value prior to the input time series (pre-bomb tritium). Lumpy also allows underground tracer production (4He or 39Ar) and the computation of a daughter product (tritiugenic 3He) as well as partial loss of the daughter product (partial re-equilibration of 3He). These additional parameters and the input functions can be defined independently for the two sub-LPMs to represent two different recharge

  7. Busca de estruturas em grandes escalas em altos redshifts

    NASA Astrophysics Data System (ADS)

    Boris, N. V.; Sodrã©, L., Jr.; Cypriano, E.

    2003-08-01

    A busca por estruturas em grandes escalas (aglomerados de galáxias, por exemplo) é um ativo tópico de pesquisas hoje em dia, pois a detecção de um único aglomerado em altos redshifts pode por vínculos fortes sobre os modelos cosmológicos. Neste projeto estamos fazendo uma busca de estruturas distantes em campos contendo pares de quasares próximos entre si em z Â3 0.9. Os pares de quasares foram extraídos do catálogo de Véron-Cetty & Véron (2001) e estão sendo observados com os telescópios: 2,2m da University of Hawaii (UH), 2,5m do Observatório de Las Campanas e com o GEMINI. Apresentamos aqui a análise preliminar de um par de quasares observado nos filtros i'(7800 Å) e z'(9500 Å) com o GEMINI. A cor (i'-z') mostrou-se útil para detectar objetos "early-type" em redshifts menores que 1.1. No estudo do par 131046+0006/J131055+0008, com redshift ~ 0.9, o uso deste método possibilitou a detecção de sete objetos candidatos a galáxias "early-type". Num mapa da distribuição projetada dos objetos para 22 < i' < 25 observou-se que estas galáxias estão localizadas próximas a um dos quasares e há indícios de que estejam aglomeradas dentro de um área de ~ 6 arcmin2. Se esse for o caso, estes objetos seriam membros de uma estrutura em grande escala. Um outro argumento em favor dessa hipótese é que eles obedecem uma relação do tipo Kormendy (raio equivalente X brilho superficial dentro desse raio), como a apresentada pelas galáxias elípticas em z = 0.

  8. Diagnosis and treatment of MS in Latin America. MS Forum Interactive Symposium at the LACTRIMS Congress, 27 August 2004, Iguazu Falls, Brazil.

    PubMed

    Montalban, Xavier

    2004-12-01

    The LACTRIMS congress at Foz do Iguacu attracted approximately 500 delegates, representing an important medium for increasing awareness of MS within the neurology community in Latin America. It also provided a forum for neurologists in Latin America, who are already diagnosing and treating patients with MS, to discuss ideas and exchange experiences. This year's congress discussed comprehensive management of patients with MS in Latin America, and how best to achieve this within the context of the local healthcare system. An MS Forum Interactive Symposium formed part of the congress programme and gave attendees the opportunity to learn more about the MS Forum and its activities, as well as managing MS.

  9. Fast and accurate database searches with MS-GF+Percolator.

    PubMed

    Granholm, Viktor; Kim, Sangtae; Navarro, José C F; Sjölund, Erik; Smith, Richard D; Käll, Lukas

    2014-02-07

    One can interpret fragmentation spectra stemming from peptides in mass-spectrometry-based proteomics experiments using so-called database search engines. Frequently, one also runs post-processors such as Percolator to assess the confidence, infer unique peptides, and increase the number of identifications. A recent search engine, MS-GF+, has shown promising results, due to a new and efficient scoring algorithm. However, MS-GF+ provides few statistical estimates about the peptide-spectrum matches, hence limiting the biological interpretation. Here, we enabled Percolator processing for MS-GF+ output and observed an increased number of identified peptides for a wide variety of data sets. In addition, Percolator directly reports p values and false discovery rate estimates, such as q values and posterior error probabilities, for peptide-spectrum matches, peptides, and proteins, functions that are useful for the whole proteomics community.

  10. GeMS/GSAOI performances from a user perspective

    NASA Astrophysics Data System (ADS)

    Dalessandro, Emanuele; Saracino, Sara; Origlia, Livia; Marchetti, Enrico; Ferraro, Francesco R.; Lanzoni, Barbara; Geisler, Douglas; Mauro, Francesco

    2016-07-01

    Ground-based near-IR imagers assisted by Multi Conjugate Adaptive Optics (MCAO) systems are the technological frontier to obtain high-quality stellar photometry in crowded fields at the highest possible spatial resolution. The Gemini MCAO System (GeMS) feeding the Gemini South Adaptive Optics Imager (GSAOI) is the only facility of this kind currently available to the Community. We used a set of images obtained in the J and Ks bands of the central regions of two Galactic bulge globular clusters (Liller 1 and NGC 6624) with GeMS/GSAOI, under significantly different atmospheric conditions. We characterized the performances of the system in terms of efficiency and uniformity of the Point Spread Function (PSF) over the field of view with varying seeing, airmass and tip-tilt star asterisms. We also compared the PSF performances of GeMS/GSAOI with the HST/ACS ones in the F606W and F814W bands.

  11. Peptidome Analysis of Cerebrospinal Fluid by LC-MALDI MS

    PubMed Central

    Hölttä, Mikko; Zetterberg, Henrik; Mirgorodskaya, Ekaterina; Mattsson, Niklas; Blennow, Kaj; Gobom, Johan

    2012-01-01

    We report on the analysis of endogenous peptides in cerebrospinal fluid (CSF) by mass spectrometry. A method was developed for preparation of peptide extracts from CSF. Analysis of the extracts by offline LC-MALDI MS resulted in the detection of 3,000–4,000 peptide-like features. Out of these, 730 peptides were identified by MS/MS. The majority of these peptides have not been previously reported in CSF. The identified peptides were found to originate from 104 proteins, of which several have been reported to be involved in different disorders of the central nervous system. These results support the notion that CSF peptidomics may be viable complement to proteomics in the search of biomarkers of CNS disorders. PMID:22880031

  12. Biomarker Candidates of Chlamydophila pneumoniae Proteins and Protein Fragments Identified by Affinity-Proteomics Using FTICR-MS and LC-MS/MS

    NASA Astrophysics Data System (ADS)

    Susnea, Iuliana; Bunk, Sebastian; Wendel, Albrecht; Hermann, Corinna; Przybylski, Michael

    2011-04-01

    We report here an affinity-proteomics approach that combines 2D-gel electrophoresis and immunoblotting with high performance mass spectrometry to the identification of both full length protein antigens and antigenic fragments of Chlamydophila pneumoniae (C. pneumoniae). The present affinity-mass spectrometry approach effectively utilized high resolution FTICR mass spectrometry and LC-tandem-MS for protein identification, and enabled the identification of several new highly antigenic C. pneumoniae proteins that were not hitherto reported or previously detected only in other Chlamydia species, such as Chlamydia trachomatis. Moreover, high resolution affinity-MS provided the identification of several neo-antigenic protein fragments containing N- and C-terminal, and central domains such as fragments of the membrane protein Pmp21 and the secreted chlamydial proteasome-like factor (Cpaf), representing specific biomarker candidates.

  13. Independent highly sensitive characterization of asparagine deamidation and aspartic acid isomerization by sheathless CZE-ESI-MS/MS.

    PubMed

    Gahoual, Rabah; Beck, Alain; François, Yannis-Nicolas; Leize-Wagner, Emmanuelle

    2016-02-01

    Amino acids residues are commonly submitted to various physicochemical modifications occurring at physiological pH and temperature. Post-translational modifications (PTMs) require comprehensive characterization because of their major influence on protein structure and involvement in numerous in vivo process or signaling. Mass spectrometry (MS) has gradually become an analytical tool of choice to characterize PTMs; however, some modifications are still challenging because of sample faint modification levels or difficulty to separate an intact peptide from modified counterparts before their transfer to the ionization source. Here, we report the implementation of capillary zone electrophoresis coupled to electrospray ionization tandem mass spectrometry (CZE-ESI-MS/MS) by the intermediate of a sheathless interfacing for independent and highly sensitive characterization of asparagine deamidation (deaN) and aspartic acid isomerization (isoD). CZE selectivity regarding deaN and isoD was studied extensively using different sets of synthetic peptides based on actual tryptic peptides. Results demonstrated CZE ability to separate the unmodified peptide from modified homologous exhibiting deaN, isoD or both independently with a resolution systematically superior to 1.29. Developed CZE-ESI-MS/MS method was applied for the characterization of monoclonal antibodies and complex protein mixture. Conserved CZE selectivity could be demonstrated even for complex samples, and foremost results obtained showed that CZE selectivity is similar regardless of the composition of the peptide. Separation of modified peptides prior to the MS analysis allowed to characterize and estimate modification levels of the sample independently for deaN and isoD even for peptides affected by both modifications and, as a consequence, enables to distinguish the formation of l-aspartic acid or d-aspartic acid generated from deaN. Separation based on peptide modification allowed, as supported by the ESI

  14. International Pediatric MS Study Group Clinical Trials Summit

    PubMed Central

    Tardieu, Marc; Amato, Maria Pia; Banwell, Brenda; Bar-Or, Amit; Ghezzi, Angelo; Kornberg, Andrew; Krupp, Lauren B.; Pohl, Daniela; Rostasy, Kevin; Tenembaum, Silvia; Waubant, Emmanuelle; Wassmer, Evangeline

    2013-01-01

    Objective: Pediatric studies for new biological agents are mandated by recent legislation, necessitating careful thought to evaluation of emerging multiple sclerosis (MS) therapies in children with MS. Challenges include a small patient population, the lack of prior randomized clinical trials, and ethical concerns. The goal of this meeting was to assess areas of consensus regarding clinical trial design and outcome measures among academic experts involved in pediatric MS care and research. Methods: The Steering Committee of the International Pediatric MS Study Group identified key focus areas for discussion. A total of 69 meeting attendees were assembled, including 35 academic experts. Regulatory and pharmaceutical representatives also attended, and provided input, which informed academic expert consensus decisions. Results: The academic experts agreed that clinical trials were necessary in pediatric MS to obtain pharmacokinetic, safety and efficacy data, and regulatory approval allowing for greater medication access. The academic experts agreed that relapse was an appropriate primary outcome measure for phase III pediatric trials. An international standardized cognitive battery was identified. The pros and cons of various trial designs were discussed. Guidelines surrounding MRI studies, pharmacokinetics, pharmacodynamics, and registries were developed. The academic experts agreed that given the limited subject pool, a stepwise approach to the launch of clinical trials for the most promising medications is necessary in order to ensure study completion. Alternative approaches could result in unethical exposure of patients to trial conditions without gaining knowledge. Conclusion: Consensus points for conduct of clinical trials in the rare disease pediatric MS were identified amongst a panel of academic experts, informed by regulatory and industry stakeholders. PMID:23509048

  15. Diagnosis of MS: a comparison of three different clinical settings.

    PubMed

    Porter, B; Keenan, E; Record, E; Thompson, A J

    2003-10-01

    In order to compare a newly established diagnostic clinic with two existing clinical settings in the management of the diagnostic phase of multiple sclerosis (MS), a retrospective audit was performed over a 12-month period comparing the length of time, adherence to recently published standards and price charged in diagnosing MS in three different clinical diagnostic settings operating within the same hospital: a specifically designed demyelinating disease diagnostic clinic (DDC), a general neurology clinic (GNC) and an inpatient investigation unit (IIU). An audit tool was created to measure the standards advocated by the UK MS Society on management of the diagnostic phase of MS. The costing tool was the price charged to health authorities. A randomized retrospective case note and referral letter review method was used. The entry criterion was a confirmed diagnosis of MS documented in the medical notes following investigation during the period April 1999-April 2001. The time between referral and first appointment favoured the DDC with a mean time of 5.9 weeks, compared to 7.7 weeks for the GNC and 10.0 weeks for the IIU. The mean times between the first appointment and receipt of results were 4.7 weeks (DDC), 18.8 weeks (GNC) and 21.2 weeks (IIU). Prices ranged from pounds sterling 395-pounds sterling 790 (DDC), pounds sterling 95-pounds sterling 380 (GNC) and pounds sterling 1940-pounds sterling 2700 (IIU). This study suggests that the UK MS Society standards are achievable in most areas without excessive additional costs and provides evidence that the DDC offers a better service than other existing models.

  16. A generic screening methodology for horse doping control by LC-TOF-MS, GC-HRMS and GC-MS.

    PubMed

    Kioussi, Maroula K; Lyris, Emmanouil M; Angelis, Yiannis S; Tsivou, Maria; Koupparis, Michael A; Georgakopoulos, Costas G

    2013-12-15

    In the present study a general screening protocol was developed to detect prohibited substances and metabolites for doping control purposes in equine sports. It was based on the establishment of a unified sample preparation and on the combined implementation of liquid and gas chromatographic MS analysis. The sample pretreatment began with two parallel procedures: enzymatic hydrolysis of sulfate and glucuronide conjugates, and methanolysis of the 17β-sulfate steroid conjugates. The extracts were treated for LC-TOF-MS, GC-HRMS and GC-MS assays. The majority of the prohibited substances were identified through a high mass accuracy technique, such as LC-TOF-MS, without prior derivatization. The sample preparation procedure included the formation of methylated and trimethylsilylated derivatives common in toxicological GC-MS libraries. The screening method was enhanced by post-run library searching using automated mass spectral deconvolution and identification system (AMDIS) combined with deconvolution reporting software (DRS). The current methodology is able to detect the presence of more than 350 target analytes in horse urine and may easily incorporate a lot of new substances without changes in chromatography. The full scan acquisition allows retrospective identification of prohibited substances in stored urine samples after reprocessing of the acquired data. Validation was performed for sixty representative compounds and included limit of detection, matrix interference - specificity, extraction recovery, precision, mass accuracy, matrix effect and carry over contamination. The suitability of the method was demonstrated with previously declared positive horse urine samples.

  17. Finding and confirming nontargeted pesticides using GC/MS, LC/quadrupole-time-of-flight MS, and databases.

    PubMed

    Meng, Chin-Kai; Zweigenbaum, Jerry; Fürst, Peter; Blanke, Eva

    2010-01-01

    Two methods are described for identifying unknowns in complex matrixes. One approach, suitable for nonpolar and thermally stable compounds, uses GC/MS with a deconvolution technique, followed by a spectral library search. The second approach, suitable for polar and thermally labile compounds, uses LC/quadrupole-time-of-flight (LC/Q-TOF) MS with a Molecular Feature Extractor (MFE), followed by a database search on the exact mass of each found compound. Two example analyses are presented to illustrate the GC/MS method. The first example processes data files obtained by a multiresidue analysis of pesticides in surface water. In this example, 71 pesticides were identified using Deconvolution Reporting Software in conjunction with Automated Mass Spectral Deconvolution and Identification System software. The second example illustrates the deconvolution approach in detail using peaches and pears analyzed after extraction by the quick, easy, cheap, effective, rugged, and safe (QuEChERS) protocol. The LC/Q-TOF approach is illustrated through analysis of a grape extract prepared by the QuEChERS protocol. The resulting total ion chromatogram was found by the MFE to contain 510 chemicals (components). The masses of found chemicals were subsequently searched against an Exact Mass Database of hundreds pesticides, and 15 exact mass hits were found. Several of these exact mass hits were selected for further confirmation by MS/MS analysis using the same LC/Q-TOF.

  18. Combination of TLC and HPLC-MS/MS methods. Approach to a rational quality control of Chinese star anise.

    PubMed

    Lederer, Ines; Schulzki, Grit; Gross, Julia; Steffen, Jens-Peter

    2006-03-22

    In this study, a methodological approach for an effective and reliable quality control of Chinese star anise (Illicium verum Hook. F.) is developed and validated. A combined method of TLC and HPLC-MS/MS was used for differentiation of various Illicium species, especially Chinese and Japanese star anise. Species can be distinguished by their TLC flavonoid pattern. A sensitive and selective HPLC/ESI-MS/MS method was developed for the detection and quantification of lower admixtures of I. anisatum and of further toxic Illicium species at a low concentration range using the sesquiterpene lactone anisatin as a marker. The proposed assay includes a solid-phase extraction cleanup procedure with a high recovery (>90%). Chromatographic separation of anisatin was carried out on a C18 column, followed by MS detection using ESI in negative mode. The precursor/product ion transitions m/z 327 --> 127 (quantifier) and m/z 327 --> 297 (qualifier) were monitored. Statistical evaluation of this multireaction-monitoring procedure reveals good linearity and intra- and interday precision. The limits of detection and quantification are 1.2 and 3.9 microg/kg, respectively.

  19. High-Throughput LC-MS/MS Method for Direct Quantification of Glucuronidated, Sulfated, and Free Enterolactone in Human Plasma.

    PubMed

    Nørskov, Natalja P; Kyrø, Cecilie; Olsen, Anja; Tjønneland, Anne; Knudsen, Knud Erik Bach

    2016-03-04

    Sulfation and glucuronidation constitute a major pathway in humans and may play an important role in biological activity of metabolites including the enterolignan, enterolactone. Because the aromatic structure of enterolactone has similarities to steroid metabolites, it was hypothesized that enterolactone may protect against hormone-dependent cancers. This led to numerous epidemiological studies. In this context, there has been a demand for rapid, sensitive, high-throughput methods to measure enterolactone in biofluids. Different methods have been developed using GC-MS, HPLC, LC-MS/MS and a fluoroimmunoassay; however, most of these methods measure the total concentration of enterolactone, without any specification of its conjugation pattern. Here for the first time we present a high-throughput LC-MS/MS method to quantify enterolactone in its intact form as glucuronide, sulfate, and free enterolactone. The method has shown good accuracy and precision at low concentration and very high sensitivity, with LLOQ for enterolactone sulfate at 16 pM, enterolactone glucuronide at 26 pM, and free enterolactone at 86 pM. The short run time of 2.6 min combined with simple sample clean up and high sensitivity make this method attractive for the high-throughput of samples needed for epidemiological studies. Finally, we have adapted the new method to quantify enterolactone and its conjugates in 3956 plasma samples from an epidemiological study. We found enterolactone glucuronide to be the major conjugation form and that conjugation pattern was similar between men and women.

  20. New triterpene saponins from the roots of Glycyrrhiza yunnanensis and their rapid screening by LC/MS/MS.

    PubMed

    Ji, Shuai; Wang, Qing; Qiao, Xue; Guo, Hong-cheng; Yang, Yan-fang; Bo, Tao; Xiang, Cheng; Guo, De-an; Ye, Min

    2014-03-01

    The roots of Glycyrrhiza yunnanensis Cheng f. et L. K. Dai ex P. C. Li are used as licorice in traditional medicine of Southwest China. Triterpene saponins are the major chemical constituents. In this study, one new oleanane-type triterpenoid, glyyunnansapogenin I (I), seven new triterpene saponins, yunganosides E3 (II), L (III), M (IV), N1 (V), O (VI), P (VII) and N2 (VIII), together with four known saponins (IX-XII) were isolated from the roots of G. yunnanensis by preparative chromatography. Their structures were identified by spectroscopic analysis including NMR and HR-MS. Based on (-)-ESI-MS/MS fragmentation behaviors of these reference standards, an LC/MS/MS method using neutral loss scan and precursor ion scan on a triple quadrupole mass spectrometer was established to rapidly and comprehensively analyze triterpene saponins in G. yunnanensis. Combined with high-accuracy qTOF mass spectrometry analysis, a total of 50 saponins were detected, and their structures were identified or tentatively characterized. This is the first systematic study on triterpene saponins in G. yunnanensis.