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Sample records for mass spectrometry investigations

  1. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  2. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  3. Liquid chromatography/microspray mass spectrometry for bacterial investigations.

    PubMed

    Krishnamurthy, T; Davis, M T; Stahl, D C; Lee, T D

    1999-01-01

    Cellular proteins (biomarkers) specific to any individual microorganism, determined by the direct mass spectral analysis of the corresponding intact cellular suspension, can be applied for the rapid and specific identification of the organisms present in unknown samples. The components of the bacterial suspensions, after a rapid separation over a C18 reversed-phase microcapillary column, were directly subjected to on-line electrospray ionization followed by analysis using an ion trap tandem mass spectrometer. This approach is equally effective for gram-positive as well as gram-negative bacteria but has a distinct advantage over our earlier reported method involving matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). During electrospray ionitation mass spectrometry (ESI-MS), liquid samples can be directly analyzed and there is the potential for developing tandem mass spectral methods for more specific identification of the individual organisms present in crude bacterial mixtures. The total analysis time leading to unambiguous bacterial identification in samples was less than 10 minutes and the results were quite reproducible. Miniaturization of the instrumentation along with total automation of this simple process could have immense impact on field operations. Routine, rapid, cost-effective field monitoring of environmental samples, agricultural products, samples from food processing, industrial sites and health institutions for suspected bacterial contamination could be a reality in the near future. Potential utility in biological, medical, bioprocessing, pharmaceutical, and other industrial research is also enormous.

  4. Preliminary Investigation into Pyrotechnic Chemical Products via Mass Spectrometry Techniques

    DTIC Science & Technology

    2015-03-11

    mass spectrometer via electrospray ionization. Pyrolysis‐MS is then used to investigate the gaseous products that are formed from thermal ...MS is then used to investigate the gaseous products that are formed from  thermal   decomposition of several individual components of the pyrotechnic...measurement within environmental samples 16 The United States Environmental Protection Agency (EPA) has designated 32 PAHs as Priority Pollutants

  5. Investigations of paleoclimate variations using accelerator mass spectrometry

    SciTech Connect

    Southon, J R; Kashgarian, M; Brown, T A

    2000-08-24

    This project has used Accelerator Mass Spectrometry (AMS) {sup 14}C measurements to study climate and carbon cycle variations on time scales from decades to millennia over the past 30,000 years, primarily in the western US and the North Pacific. {sup 14}C dates provide a temporal framework for records of climate change, and natural radiocarbon acts as a carbon cycle tracer in independently dated records. The overall basis for the study is the observation that attempts to model future climate and carbon cycle changes cannot be taken seriously if the models have not been adequately tested. Paleoclimate studies are unique because they provide realistic test data under climate conditions significantly different from those of the present, whereas instrumental results can only sample the system as it is today. The aim of this project has been to better establish the extent, timing, and causes of past climate perturbations, and the carbon cycle changes with which they are linked. This provides real-world data for model testing, both for the development of individual models and also for inter-model diagnosis and comparison activities such as those of LLNL's PCMDI program; it helps us achieve a better basic understanding of how the climate system works so that models can be improved; and it gives an indication of the natural variability in the climate system underlying any anthropogenically-driven changes. The research has involved four projects which test hypotheses concerning the overall behavior of the North Pacific climate system. All are aspects of an overall theme that climate linkages are strong and direct, so that regional climate records are correlated, details of fine structure are important, and accurate and precise dating is critical for establishing correlations and even causality. An important requirement for such studies is the requirement for an accurate and precise radiocarbon calibration, to allow better correlation of radiocarbon-dated records with

  6. Mass spectrometry-based proteomics and analyses of serum: a primer for the clinical investigator.

    PubMed

    Fusaro, V A; Stone, J H

    2003-01-01

    The vocabulary of proteomics and the swiftly-developing, technological nature of the field constitute substantial barriers to clinical investigators. In recent years, mass spectrometry has emerged as the most promising technique in this field. The purpose of this review is to introduce the field of mass spectrometry-based proteomics to clinical investigators, to explain many of the relevant terms, to introduce the equipment employed in this field, and to outline approaches to asking clinical questions using a proteomic approach. Examples of clinical applications of proteomic techniques are provided from the fields of cancer and vasculitis research, with an emphasis on a pattern recognition approach.

  7. Ion mobility-mass spectrometry as a tool to investigate protein-ligand interactions.

    PubMed

    Göth, Melanie; Pagel, Kevin

    2017-07-01

    Ion mobility-mass spectrometry (IM-MS) is a powerful tool for the simultaneous analysis of mass, charge, size, and shape of ionic species. It allows the characterization of even low-abundant species in complex samples and is therefore particularly suitable for the analysis of proteins and their assemblies. In the last few years even complex and intractable species have been investigated successfully with IM-MS and the number of publications in this field is steadily growing. This trend article highlights recent advances in which IM-MS was used to study protein-ligand complexes and in particular focuses on the catch and release (CaR) strategy and collision-induced unfolding (CIU). Graphical Abstract Native mass spectrometry and ion mobility-mass spectrometry are versatile tools to follow the stoichiometry, energetics, and structural impact of protein-ligand binding.

  8. MASS SPECTROMETRY

    DOEpatents

    Friedman, L.

    1962-01-01

    method is described for operating a mass spectrometer to improve its resolution qualities and to extend its period of use substantially between cleanings. In this method, a small amount of a beta emitting gas such as hydrogen titride or carbon-14 methane is added to the sample being supplied to the spectrometer for investigation. The additive establishes leakage paths on the surface of the non-conducting film accumulating within the vacuum chamber of the spectrometer, thereby reducing the effect of an accumulated static charge on the electrostatic and magnetic fields established within the instrument. (AEC)

  9. MASS SPECTROMETRY

    DOEpatents

    Nier, A.O.C.

    1959-08-25

    A voltage switching apparatus is described for use with a mass spectrometer in the concentratron analysis of several components of a gas mixture. The system automatically varies the voltage on the accelerating electrode of the mass spectrometer through a program of voltages which corresponds to the particular gas components under analysis. Automatic operation may be discontinued at any time to permit the operator to manually select any desired predetermined accelerating voltage. Further, the system may be manually adjusted to vary the accelerating voltage over a wide range.

  10. Synchrotron based mass spectrometry to investigate the molecular properties of mineral-organic associations

    SciTech Connect

    Liu, Suet Yi; Kleber, Markus; Takahashi, Lynelle K.; Nico, Peter; Keiluweit, Marco; Ahmed, Musahid

    2013-04-01

    Soil organic matter (OM) is important because its decay drives life processes in the biosphere. Analysis of organic compounds in geological systems is difficult because of their intimate association with mineral surfaces. To date there is no procedure capable of quantitatively separating organic from mineral phases without creating artifacts or mass loss. Therefore, analytical techniques that can (a) generate information about both organic and mineral phases simultaneously and (b) allow the examination of predetermined high-interest regions of the sample as opposed to conventional bulk analytical techniques are valuable. Laser Desorption Synchrotron Postionization (synchrotron-LDPI) mass spectrometry is introduced as a novel analytical tool to characterize the molecular properties of organic compounds in mineral-organic samples from terrestrial systems, and it is demonstrated that when combined with Secondary Ion Mass Spectrometry (SIMS), can provide complementary information on mineral composition. Mass spectrometry along a decomposition gradient in density fractions, verifies the consistency of our results with bulk analytical techniques. We further demonstrate that by changing laser and photoionization energies, variations in molecular stability of organic compounds associated with mineral surfaces can be determined. The combination of synchrotron-LDPI and SIMS shows that the energetic conditions involved in desorption and ionization of organic matter may be a greater determinant of mass spectral signatures than the inherent molecular structure of the organic compounds investigated. The latter has implications for molecular models of natural organic matter that are based on mass spectrometric information.

  11. Applications of Mass Spectrometry in Investigations of Alleged Use of Chemical Warfare Agents

    NASA Astrophysics Data System (ADS)

    Read, Robert W.

    Chemical warfare agents were used extensively throughout the twentieth century. Many such uses are well documented; however some allegations of use of chemical warfare agents were not easily confirmed. During the early 1980s interest developed into investigation of alleged use by analytical techniques, particularly mass spectrometry. Since that time, many combined chromatographic - mass spectrometric methods have been developed, both for application to the analysis of environmental and biomedical samples and for investigation of physiological interactions of chemical warfare agents. Examples are given of some of the investigations in which the author has been involved, including those into Yellow Rain and uses of chemical warfare agents in Iraq and Iran. These examples illustrate the use of combined chromatographic-mass spectrometric methods and emphasise the importance of controls in analytical investigations.

  12. Investigation of Elemental Mass Spectrometry in Pharmacology for Peptide Quantitation at Femtomolar Levels.

    PubMed

    Cordeau, Emmanuelle; Arnaudguilhem, Carine; Bouyssiere, Brice; Hagège, Agnès; Martinez, Jean; Subra, Gilles; Cantel, Sonia; Enjalbal, Christine

    2016-01-01

    In the search of new robust and environmental-friendly analytical methods able to answer quantitative issues in pharmacology, we explore liquid chromatography (LC) associated with elemental mass spectrometry (ICP-MS) to monitor peptides in such complex biological matrices. The novelty is to use mass spectrometry to replace radiolabelling and radioactivity measurements, which represent up-to now the gold standard to measure organic compound concentrations in life science. As a proof of concept, we choose the vasopressin (AVP)/V1A receptor system for model pharmacological assays. The capacity of ICP-MS to provide highly sensitive quantitation of metallic and hetero elements, whatever the sample medium, prompted us to investigate this technique in combination with appropriate labelling of the peptide of interest. Selenium, that is scarcely present in biological media, was selected as a good compromise between ICP-MS response, covalent tagging ability using conventional sulfur chemistry and peptide detection specificity. Applying selenium monitoring by elemental mass spectrometry in pharmacology is challenging due to the very high salt content and organic material complexity of the samples that produces polyatomic aggregates and thus potentially mass interferences with selenium detection. Hyphenation with a chromatographic separation was found compulsory. Noteworthy, we aimed to develop a straightforward quantitative protocol that can be performed in any laboratory equipped with a standard macrobore LC-ICP-MS system, in order to avoid time-consuming sample treatment or special implementation of instrumental set-up, while allowing efficient suppression of all mass interferences to reach the targeted sensitivity. Significantly, a quantification limit of 57 ng Se L-1 (72 femtomoles of injected Se) was achieved, the samples issued from the pharmacological assays being directly introduced into the LC-ICP-MS system. The established method was successfully validated and

  13. Investigation of Elemental Mass Spectrometry in Pharmacology for Peptide Quantitation at Femtomolar Levels

    PubMed Central

    Cordeau, Emmanuelle; Arnaudguilhem, Carine; Bouyssiere, Brice; Hagège, Agnès; Martinez, Jean; Subra, Gilles; Cantel, Sonia

    2016-01-01

    In the search of new robust and environmental-friendly analytical methods able to answer quantitative issues in pharmacology, we explore liquid chromatography (LC) associated with elemental mass spectrometry (ICP-MS) to monitor peptides in such complex biological matrices. The novelty is to use mass spectrometry to replace radiolabelling and radioactivity measurements, which represent up-to now the gold standard to measure organic compound concentrations in life science. As a proof of concept, we choose the vasopressin (AVP)/V1A receptor system for model pharmacological assays. The capacity of ICP-MS to provide highly sensitive quantitation of metallic and hetero elements, whatever the sample medium, prompted us to investigate this technique in combination with appropriate labelling of the peptide of interest. Selenium, that is scarcely present in biological media, was selected as a good compromise between ICP-MS response, covalent tagging ability using conventional sulfur chemistry and peptide detection specificity. Applying selenium monitoring by elemental mass spectrometry in pharmacology is challenging due to the very high salt content and organic material complexity of the samples that produces polyatomic aggregates and thus potentially mass interferences with selenium detection. Hyphenation with a chromatographic separation was found compulsory. Noteworthy, we aimed to develop a straightforward quantitative protocol that can be performed in any laboratory equipped with a standard macrobore LC-ICP-MS system, in order to avoid time-consuming sample treatment or special implementation of instrumental set-up, while allowing efficient suppression of all mass interferences to reach the targeted sensitivity. Significantly, a quantification limit of 57 ng Se L-1 (72 femtomoles of injected Se) was achieved, the samples issued from the pharmacological assays being directly introduced into the LC-ICP-MS system. The established method was successfully validated and

  14. Qualitative and quantitative metabolomic investigation of single neurons by capillary electrophoresis electrospray ionization mass spectrometry

    PubMed Central

    Nemes, Peter; Rubakhin, Stanislav S.; Aerts, Jordan T.; Sweedler, Jonathan V.

    2013-01-01

    Single-cell mass spectrometry (MS) empowers metabolomic investigations by decreasing analytical dimensions to the size of individual cells and subcellular structures. We describe a protocol for investigating and quantifying metabolites in individual isolated neurons using single-cell capillary electrophoresis hyphenated to electrospray ionization time-of-flight MS. The protocol requires ~2 h for sample preparation, neuron isolation, and metabolite extraction, and 1 h for metabolic measurement. The approach was used to detect more than 300 distinct compounds in the mass range of typical metabolites in various individual neurons (25–500-µm in diameter) isolated from the sea slug (Aplysia californica) central and rat (Rattus norvegicus) peripheral nervous systems. A subset of identified compounds was sufficient to reveal metabolic differences among freshly isolated neurons of different types and changes in the metabolite profiles of cultured neurons. The protocol can be applied to the characterization of the metabolome in a variety of smaller cells and/or subcellular domains. PMID:23538882

  15. Mass Spectrometry-Based Proteomics for Investigating DNA Damage-Associated Protein Ubiquitylation

    PubMed Central

    Heidelberger, Jan B.; Wagner, Sebastian A.; Beli, Petra

    2016-01-01

    Modification of proteins with the 76 amino acid protein ubiquitin plays essential roles in cellular signaling. Development of methods for specific enrichment of ubiquitin remnant peptides and advances in high-resolution mass spectrometry have enabled proteome-wide identification of endogenous ubiquitylation sites. Moreover, ubiquitin remnant profiling has emerged as a powerful approach for investigating changes in protein ubiquitylation in response to cellular perturbations, such as DNA damage, as well as for identification of substrates of ubiquitin-modifying enzymes. Despite these advances, interrogation of ubiquitin chain topologies on substrate proteins remains a challenging task. Here, we describe mass spectrometry-based approaches for quantitative analyses of site-specific protein ubiquitylation and highlight recent studies that employed these methods for investigation of ubiquitylation in the context of the cellular DNA damage response. Furthermore, we provide an overview of experimental strategies for probing ubiquitin chain topologies on proteins and discuss how these methods can be applied to analyze functions of ubiquitylation in the DNA damage response. PMID:27379159

  16. A mass spectrometry platform for a streamlined investigation of proteasome integrity, posttranslational modifications, and inhibitor binding.

    PubMed

    Gersch, Malte; Hackl, Mathias W; Dubiella, Christian; Dobrinevski, Alexander; Groll, Michael; Sieber, Stephan A

    2015-03-19

    The proteasome is responsible for the majority of protein degradation within eukaryotic cells and proteasome inhibitors have gained blockbuster status as anticancer drugs. Here, we introduce an analytical platform comprising reverse phase chromatography, intact protein mass spectrometry, and customized data analysis that allows a streamlined investigation of proteasome integrity and posttranslational modifications. We report the complete mass spectrometric assignment of all subunits of the yeast core particle, as well as of the human constitutive 20S proteasome and the human immunoproteasome, including phosphorylated isoforms of α7. Importantly, we found several batches of commercially available immunoproteasome to also contain constitutive catalytic subunits. Moreover, we applied the method to study the binding mechanisms of proteasome inhibitors, both validating the approach and providing a direct readout of subunit preferences complementary to biochemical methods. Collectively, our platform facilitates an easy, reliable and comprehensive detection of different types of covalent modifications on multisubunit protein complexes with high accuracy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Dyeing regions of oxidative hair dyes in human hair investigated by nanoscale secondary ion mass spectrometry.

    PubMed

    Kojima, Toru; Yamada, Hiromi; Yamamoto, Toshihiko; Matsushita, Yasuyuki; Fukushima, Kazuhiko

    2013-06-01

    To develop more effective oxidative hair coloring products, it is important to understand the localization of colored chromophores, which are formed from oxidative dyes, in the fine structure of hair. However, the dyeing regions of oxidative hair dyes in the fine structure of hair have not been extensively examined. In this study, we investigated the distribution and localization of colored chromophores formed by an oxidative hair coloring product in the fine structure of human hair by using a stable isotope-labeled oxidative dye with nanoscale secondary ion mass spectrometry (NanoSIMS). First, formation of the colored chromophore from a deuterium-labeled oxidative dye was examined by visible spectra similarly to a study of its formation using nonlabeled oxidative dye. Furthermore, the formation of binuclear indo dye containing deuterium in its chemical structure was confirmed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis. As a result of the NanoSIMS image on a cross-sectional dyed hair, although deuterium ions were detected in whole hair cross-section, quite a few of them were detected at particulate regions. These particulate regions of the dyed black hair in which deuterium ions were intensely detected were identified as melanin granules, by comparing the dyeing behaviors of black and white hair. NanoSIMS analysis revealed that melanin granules of black human hair are important dyeing regions in oxidative hair coloring. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Thin-Layer Chromatography/Desorption Electrospray Ionization Mass Spectrometry: Investigation of Goldenseal Alkaloids

    SciTech Connect

    Van Berkel, Gary J; Tomkins, Bruce A; Kertesz, Vilmos

    2007-01-01

    Desorption electrospray ionization mass spectrometry was investigated as a means to qualitatively identify and to quantify analytes directly from developed normal-phase thin layer chromatography plates. The atmospheric sampling capillary of a commercial ion trap mass spectrometer was extended to permit sampling and ionization of analytes in bands separated on intact TLC plates (up to 10 cm x 10 cm). A surface positioning software package and the appropriate hardware enabled computer-controlled surface scanning along the length of development lanes or at fixed RF value across the plates versus the stationary desorption electrospray emitter. Goldenseal (Hydrastis canadensis) and related alkaloids and commercial dietary supplements were used as standards and samples. Alkaloid standards and samples were spotted and separated on aluminum- or glass-backed plates using established literature methods. The mass spectral signal levels as a function of desorption spray solvent were investigated with acetonitrile proving superior to methanol. The detection levels (ca. 5 ng each or 14 -28 pmol) in mass spectral full scan mode were determined statistically from the calibration curves (2.5 - 100 pmol) for the standards berberine, palmatine and hydrastinine spotted as a mixture and separated on the plates. Qualitative screening of the major alkaloids present in six different over-the-counter "goldenseal" dietary supplements was accomplished by obtaining full scan mass spectra during surface scans along the development lane in the direction of increasing RF value. In one sample, alkaloids were detected that strongly suggested the presence of at least one additional herb undeclared on the product label. These same data indicated the misidentification of one of the alkaloids in the TLC literature. Quantities of the alkaloids present in two of the samples determined using the mass spectral data were in reasonable agreement with the label values indicating the quantitative ability of

  19. Investigation of formation and ageing of biogenic secondary aerosols by soft ionization aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Müller, Lars; Reinnig, Marc-Christopher; Vogel, Alexander; Mentel, Thomas; Tillmann, Ralf; Schlosser, E.; Wahner, Andreas; Donahue, Neil; Saathoff, Harald; Hoffmann, Thorsten

    2010-05-01

    The knowledge of the chemical composition of secondary organic aerosol is one essential key to understand the significance and fate of SOA in the atmosphere. However, the chemical evolution of SOA, from the very first condensing/nucleating molecules to the final oxidation products is still insufficiently understood and object of current research [1-3]. Consequently, the formation and photochemical ageing of secondary organic aerosol (SOA) was investigated in a series of reaction chamber experiments by applying on-line aerosol mass spectrometry (atmospheric pressure chemical ionization mass spectrometry (APCI/MS)) as well as off-line high performance liquid chromatography mass spectrometry (HPLC-MS). In a set of experiments, performed in the large outdoor reaction chamber SAPHIR (Jülich, Germany), SOA was generated from a boreal mixture of biogenic VOCs. During a two-day experiment the generated biogenic SOA was exposed to OH-radicals and the temporal evolution of the chemical composition was characterized. The applied on-line MS method not only provides highly time resolved chemical information (such as an AMS) but also allows molecular identification/quantification of specific marker compounds. Several first and higher generation BSOA products were identified. Among the higher generation products, especially a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid) [2] was observed as an eye-catching oxidative processing marker. A more detailed investigation of hydroxyl radical induced SOA aging at the AIDA chamber facility in Karlsruhe, again using terpenes as SOA precursors, clearly showed that the formation of the tricarboxylic acid takes place in the gas phase by the reaction of semivolatile first generation products and hydroxyl radicals. Actually, there were no indications for OH induced oxidation of compounds in the condensed phase. The consequences of these results will be discussed in the contribution. 1. Rudich, Y., N.M. Donahue, and T.F. Mentel

  20. Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry.

    PubMed

    Lu, Mei; Liu, Yong; Helmy, Roy; Martin, Gary E; Dewald, Howard D; Chen, Hao

    2015-10-01

    Electrochemistry (EC) combined with mass spectrometry (MS) is a powerful tool for elucidation of electrochemical reaction mechanisms. However, direct online analysis of electrochemical reaction in aqueous phase was rarely explored. This paper presents the online investigation of several electrochemical reactions with biological relevance in the aqueous phase, such as nitrosothiol reduction, carbohydrate oxidation, and carbamazepine oxidation using desorption electrospray ionization mass spectrometry (DESI-MS). It was found that electroreduction of nitrosothiols [e.g., nitrosylated insulin B (13-23)] leads to free thiols by loss of NO, as confirmed by online MS analysis for the first time. The characteristic mass shift of 29 Da and the reduced intensity provide a quick way to identify nitrosylated species. Equally importantly, upon collision-induced dissociation (CID), the reduced peptide ion produces more fragment ions than its nitrosylated precursor ion (presumably the backbone fragmentation cannot compete with the facile NO loss for the precursor ion), thus facilitating peptide sequencing. In the case of saccharide oxidation, it was found that glucose undergoes electro-oxidation to produce gluconic acid at alkaline pH, but not at neutral and acidic pHs. Such a pH-dependent electrochemical behavior was also observed for disaccharides such as maltose and cellobiose. Upon electrochemical oxidation, carbamazepine was found to undergo ring contraction and amide bond cleavage, which parallels the oxidative metabolism observed for this drug in leucocytes. The mechanistic information of these redox reactions revealed by EC/DESI-MS would be of value in nitroso-proteome research and carbohydrate/drug metabolic studies.

  1. Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lu, Mei; Liu, Yong; Helmy, Roy; Martin, Gary E.; Dewald, Howard D.; Chen, Hao

    2015-08-01

    Electrochemistry (EC) combined with mass spectrometry (MS) is a powerful tool for elucidation of electrochemical reaction mechanisms. However, direct online analysis of electrochemical reaction in aqueous phase was rarely explored. This paper presents the online investigation of several electrochemical reactions with biological relevance in the aqueous phase, such as nitrosothiol reduction, carbohydrate oxidation, and carbamazepine oxidation using desorption electrospray ionization mass spectrometry (DESI-MS). It was found that electroreduction of nitrosothiols [e.g., nitrosylated insulin B (13-23)] leads to free thiols by loss of NO, as confirmed by online MS analysis for the first time. The characteristic mass shift of 29 Da and the reduced intensity provide a quick way to identify nitrosylated species. Equally importantly, upon collision-induced dissociation (CID), the reduced peptide ion produces more fragment ions than its nitrosylated precursor ion (presumably the backbone fragmentation cannot compete with the facile NO loss for the precursor ion), thus facilitating peptide sequencing. In the case of saccharide oxidation, it was found that glucose undergoes electro-oxidation to produce gluconic acid at alkaline pH, but not at neutral and acidic pHs. Such a pH-dependent electrochemical behavior was also observed for disaccharides such as maltose and cellobiose. Upon electrochemical oxidation, carbamazepine was found to undergo ring contraction and amide bond cleavage, which parallels the oxidative metabolism observed for this drug in leucocytes. The mechanistic information of these redox reactions revealed by EC/DESI-MS would be of value in nitroso-proteome research and carbohydrate/drug metabolic studies.

  2. Development of Laser Desorption Imaging Mass Spectrometry Methods to Investigate the Molecular Composition of Latent Fingermarks

    NASA Astrophysics Data System (ADS)

    Lauzon, Nidia; Dufresne, Martin; Chauhan, Vinita; Chaurand, Pierre

    2015-06-01

    For a century, fingermark analysis has been one of the most important and common methods in forensic investigations. Modern chemical analysis technologies have added the potential to determine the molecular composition of fingermarks and possibly identify chemicals a suspect may have come into contact with. Improvements in analytical detection of the molecular composition of fingermarks is therefore of great importance. In this regard, matrix-assisted laser desorption ionization (MALDI) and laser desorption ionization (LDI) imaging mass spectrometry (IMS) have proven to be useful technologies for fingermark analysis. In these analyses, the choice of ionizing agent and its mode of deposition are critical steps for the identification of molecular markers. Here we propose two novel and complementary IMS approaches for endogenous and exogenous substance detection in fingermarks: sublimation of 2-mercaptobenzothiazol (2-MBT) matrix and silver sputtering.

  3. Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

    SciTech Connect

    Saetveit, Nathan Joe

    2008-01-01

    Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 μg L-1 or better were found for P, Mn, Fe, Cu, and Zn in a 60 μL injection in a physiological saline matrix.

  4. Mass spectrometry investigation of Titan aerosols analogs formed with traces of aromatic compounds

    NASA Astrophysics Data System (ADS)

    Gautier, Thomas; Trainer, Melissa; Sebree, Joshua; Li, Xiang; Pinnick, Veronica; Getty, Stephanie; Brinckerhoff, Will

    2016-06-01

    The detection of benzene at ppm levels in Titan's atmosphere [1] by Cassini's Ion and Neutral Mass Spectrometer (INMS) supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titan's aerosols formation. In laboratory studies it has been shown that these aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation [2] and be used to dope the production of aerosol analogs [3]. In this work we investigate the effect on the aerosol composition and growth pattern of the chemical nature of the aromatic reactant used to produce aerosol. Analysis are performed using Laser Desorption-Time of Flight mass spectrometry (LD-TOF) and Fourier Transform Infrared Spectroscopy (FTIR) Infrared analysis of our samples shows that inclusion of aromatic compounds as trace precursors allows to better fit laboratory data to Titan aerosol spectra observed by Cassini [3,4]. The improvement is especially visible on the far infrared (˜200 cm-1) bands observed by CIRS [5]. LDMS results show that the aerosol growth patterns depend both on the number of rings and on the nitrogen content of the trace precursor used. We also perform MS/MS analysis on some prominent peaks of aerosol mass spectra. This MS/MS approach allows us to identify some of the key compounds in the aerosol growth processes.

  5. The investigation of ionization conditions in the trace amounts detection of heterocyclic compounds by ion mobility spectrometry and mass spectrometry

    NASA Astrophysics Data System (ADS)

    Shaltaeva, Y. R.; Sysoev, A. A.; Poteshin, S. S.; Negru, K. I.; Grishin, S. S.; Trefilova, V. V.; Zuev, M. I.; Baberkina, E. P.

    2016-10-01

    The first part of paper is devoted to the detection of New Psychoactive Substances by ion mobility mass spectrometry study. In the second part of the paper presents a promising approach to prevent the spread of narcotic substances, consisting in the use of field-portable ion mobility spectrometers and finding the correlation between the peaks of the spectrograms of ion mobility and the chemical structure of the compound.

  6. Fourier Transform Mass Spectrometry.

    ERIC Educational Resources Information Center

    Gross, Michael L.; Rempel, Don L.

    1984-01-01

    Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

  7. INVESTIGATION OF ARSINE-GENERATING REACTIONS USING DEUTERIUM-LABELED REAGENTS AND MASS SPECTROMETRY

    EPA Science Inventory

    Mass spectrometry was used to detect transfer of deuterium from labeled reagents to arsines following hydride-generation reactions. The arsine gases liberated from the reactions of arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid with HC1 and NaBD4 in H2O, or with...

  8. Mass Spectrometry for the Masses

    ERIC Educational Resources Information Center

    Persinger, Jared D.; Hoops, Geoffrey, C.; Samide, Michael J.

    2004-01-01

    A simple, qualitative experiment is developed for implementation, where the gas chromatography-mass spectrometry (GC-MS) plays an important role, into the laboratory curriculum of a chemistry course designed for nonscience majors. This laboratory experiment is well suited for the students as it helps them to determine the validity of their…

  9. Mass Spectrometry for the Masses

    ERIC Educational Resources Information Center

    Persinger, Jared D.; Hoops, Geoffrey, C.; Samide, Michael J.

    2004-01-01

    A simple, qualitative experiment is developed for implementation, where the gas chromatography-mass spectrometry (GC-MS) plays an important role, into the laboratory curriculum of a chemistry course designed for nonscience majors. This laboratory experiment is well suited for the students as it helps them to determine the validity of their…

  10. Investigation of the interaction of Mercurochrome constituents with proteins using liquid chromatography/mass spectrometry.

    PubMed

    Wilken, Andrea; Janzen, Rasmus; Holtkamp, Michael; Nowak, Sascha; Sperling, Michael; Vogel, Martin; Karst, Uwe

    2010-08-01

    The interaction of Mercurochrome, a medical preparation based on the mercury organic compound merbromin, with free thiols in low molecular weight peptides and in proteins has been investigated by means of liquid chromatography (LC) and electrospray mass spectrometry (ESI-MS). Beta-lactoglobulin A (beta-LGA) from bovine milk (18.4 kDa) has been used as the model protein. It was found that, in contrast to assumptions in literature, the commercial product itself is a heterogeneous mixture of moderate chemical stability, which may contain precipitated Hg salts depending on storage time and conditions. Further variability results from different degrees of bromination of the fluorescein backbone of the compound. The formation of mercury compound-protein adducts was detected. The peptide sequence T13 containing a free thiol residue was identified as the binding site for mercury species after tryptic digestion of beta-lactoglobulin A. While fresh Mercurochrome tends to the formation of a Hg(II)-beta-LGA adducts due to excess Hg(2+) in solution, investigations after precipitation of Hg salts yield Hg(merbromin)(beta-LGA) as the major product.

  11. High resolution mass spectrometry to investigate omeprazole and venlafaxine metabolites in wastewater.

    PubMed

    Boix, Clara; Ibáñez, María; Bagnati, Renzo; Zuccato, Ettore; Sancho, Juan V; Hernández, Félix; Castiglioni, Sara

    2016-01-25

    This study reports an investigation of omeprazole and venlafaxine parent substances and metabolites in Italian municipal influent wastewaters (IWWs). These pharmaceuticals were selected because they are widely consumed in Italy, but are poorly detected in waste and surface water. The aim of the study was to identify the most relevant pharmaceuticals metabolites in wastewater in order to improve the prioritization step and choose priority pollutants for environmental monitoring campaigns. This was done by investigating omeprazole, venlafaxine and their main metabolites in 30 IWWs from ten Italian cities and by comparing results with information from pharmacokinetic studies. Analysis was performed by solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) coupled to high resolution mass spectrometry (HRMS). We searched for 23 omeprazole and four venlafaxine metabolites using data-dependent and MS/MS methods. Parent omeprazole was never present in the samples. Six omeprazole metabolites were found in IWWs. Venlafaxine and two metabolites were present in all the samples. The metabolic profiles in Italian IWW agreed with results in IWW from Spain and with urinary excretion profiles from pharmacokinetic studies. Comparing results from different sources was useful to improve the identification of pharmaceuticals metabolites in environmental samples and to focus the attention of future studies on the most relevant compounds.

  12. Investigating the Lymphatic System by Dual-Color Elemental Mass Spectrometry Imaging

    PubMed Central

    Niehoff, Ann-Christin; Klasen, Tim; Schmidt, Rebecca; Palmes, Daniel; Faber, Cornelius

    2017-01-01

    Secondary lymphedema accompanied with strong restrictions in quality of life is still major side effects in cancer therapy. Therefore, dedicated diagnostic tools and further investigation of the lymphatic system are crucial to improve lymphedema therapy. In this pilot study, a method for quantitative analysis of the lymphatic system in a rat model by laser ablation (LA) with inductively coupled plasma mass spectrometry imaging (ICP-MSI) is presented. As a possible lymph marker, thulium(III)(1R,4R,7R,10R)-α,α′,α′′,α′′′-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (Tm-DOTMA) is introduced and compared to the clinically used magnetic resonance imaging contrast agent gadolinium(III)2,2′,2′′-(10-((2R,3S)-1,3,4-trihydroxybutan-2-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate (Gd-DO3A-butrol). Gadobutrol functioned as standard contrast media in MRI lymphangiography to detect lymphatic flow qualitatively. Thus, Tm-DOTMA was investigated as lymphatic marker to detect lymphatic flow quantitatively. Both contrast agents were successfully used to visualize the lymphatic flow in successive lymph nodes in LA-ICP-MS due to lower limits of detection compared to MRI. Furthermore, the distribution of contrast agents by multicolored imaging showed accumulation in specific areas (sectors) of the lymph nodes after application of contrast agents in different areas.

  13. Forensic Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Hoffmann, William D.; Jackson, Glen P.

    2015-07-01

    Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques.

  14. Forensic Mass Spectrometry.

    PubMed

    Hoffmann, William D; Jackson, Glen P

    2015-01-01

    Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques.

  15. Investigation of a measure of robustness in inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Makonnen, Yoseif; Beauchemin, Diane

    2015-01-01

    In industrial/commercial settings where operators often have minimal expertise in inductively coupled plasma (ICP) mass spectrometry (MS), there is a prevalent need for a response factor indicating robust plasma conditions, which is analogous to the Mg II/Mg I ratio in ICP optical emission spectrometry (OES), whereby a Mg II/Mg I ratio of 10 constitutes robust conditions. While minimizing the oxide ratio usually corresponds to robust conditions, there is no specific target value that is widely accepted as indicating robust conditions. Furthermore, tuning for low oxide ratios does not necessarily guarantee minimal matrix effects, as they really address polyatomic interferences. From experiments, conducted in parallel for both MS and OES, there were some element pairs of similar mass and very different ionization potential that were exploited for such a purpose, the rationale being that, if these elements were ionized to the same extent, then that could be indicative of a robust plasma. The Be II/Li I intensity ratio was directly related to the Mg II/Mg I ratio in OES. Moreover, the 9Be+/7Li+ ratio was inversely related to the CeO+/Ce+ and LaO+/La+ oxide ratios in MS. The effects of different matrices (i.e. 0.01-0.1 M Na) were also investigated and compared to a conventional argon plasma optimized for maximum sensitivity. The suppression effect of these matrices was significantly reduced, if not eliminated in the case of 0.01 M Na, when the 9Be+/7Li+ ratio was around 0.30 on the Varian 820 MS instrument. Moreover, a very similar ratio (0.28) increased robustness to the same extent on a completely different ICP-MS instrument (PerkinElmer NEXION). Much greater robustness was achieved using a mixed-gas plasma with nitrogen in the outer gas and either nitrogen or hydrogen as a sheathing gas, as the 9Be+/7Li+ ratio was then around 1.70. To the best of our knowledge, this is the first report on using a simple analyte intensity ratio, 9Be+/7Li+, to gauge plasma robustness.

  16. Experimental and Theoretical Investigation of Sodiated Multimers of Steroid Epimers with Ion Mobility-Mass Spectrometry.

    PubMed

    Chouinard, Christopher D; Cruzeiro, Vinícius Wilian D; Roitberg, Adrian E; Yost, Richard A

    2017-02-01

    Ion mobility-mass spectrometry (IM-MS) has recently seen increased use in the analysis of small molecules, especially in the field of metabolomics, for increased breadth of information and improved separation of isomers. In this study, steroid epimers androsterone and trans-androsterone were analyzed with IM-MS to investigate differences in their relative mobilities. Although sodiated monomers exhibited very similar collision cross-sections (CCS), baseline separation was observed for the sodiated dimer species (RS = 1.81), with measured CCS of 242.6 and 256.3 Å(2), respectively. Theoretical modeling was performed to determine the most energetically stable structures of solution-phase and gas-phase monomer and dimer structures. It was revealed that these epimers differ in their preferred dimer binding mode in solution phase: androsterone adopts a R=O - Na(+) - OH-R' configuration, whereas trans-androsterone adopts a R=O - Na(+) - O=R' configuration. This difference contributes to a significant structural variation, and subsequent CCS calculations based on these structures relaxed in the gas phase were in agreement with experimentally measured values (ΔCCS ~ 5%). Additionally, these calculations accurately predicted the relative difference in mobility between the epimers. This study illustrates the power of combining experimental and theoretical results to better elucidate gas-phase structures. Graphical Abstract ᅟ.

  17. Experimental and Theoretical Investigation of Sodiated Multimers of Steroid Epimers with Ion Mobility-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chouinard, Christopher D.; Cruzeiro, Vinícius Wilian D.; Roitberg, Adrian E.; Yost, Richard A.

    2017-02-01

    Ion mobility-mass spectrometry (IM-MS) has recently seen increased use in the analysis of small molecules, especially in the field of metabolomics, for increased breadth of information and improved separation of isomers. In this study, steroid epimers androsterone and trans-androsterone were analyzed with IM-MS to investigate differences in their relative mobilities. Although sodiated monomers exhibited very similar collision cross-sections (CCS), baseline separation was observed for the sodiated dimer species (RS = 1.81), with measured CCS of 242.6 and 256.3 Å2, respectively. Theoretical modeling was performed to determine the most energetically stable structures of solution-phase and gas-phase monomer and dimer structures. It was revealed that these epimers differ in their preferred dimer binding mode in solution phase: androsterone adopts a R=O - Na+ - OH—R' configuration, whereas trans-androsterone adopts a R=O - Na+ - O=R' configuration. This difference contributes to a significant structural variation, and subsequent CCS calculations based on these structures relaxed in the gas phase were in agreement with experimentally measured values (ΔCCS 5%). Additionally, these calculations accurately predicted the relative difference in mobility between the epimers. This study illustrates the power of combining experimental and theoretical results to better elucidate gas-phase structures.

  18. Plasma Lipidomics Investigation of Hemodialysis Effects by Using Liquid Chromatography-Mass Spectrometry.

    PubMed

    Wang, Lichao; Hu, Chunxiu; Liu, Shuxin; Chang, Ming; Gao, Peng; Wang, Lili; Pan, Zaifa; Xu, Guowang

    2016-06-03

    Chronic kidney disease (CKD) has been a global health problem that has a great possibility of being developed into uremia in the end. Hemodialysis (HD) is the most commonly used strategy for treating uremic patients; however, the patients still have a high risk of suffering various complications. It is well recognized that lipid disorder usually occurs in maintenance HD patients. To systemically study the effects of HD on lipid metabolism associated with uremia, we employed an ultraperformance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based lipidomics method. A total of 87 human plasma samples from patients with prehemodialysis (pre-HD)/posthemodialysis (post-HD) treatment and the healthy controls were enrolled in the study. As compared with pre-HD patients, many plasma lipids showed significant changes (p < 0.05) in patients receiving HD therapy. Specifically, sum of free fatty acids (FFA) as well as saturated FFA and eicosanoids and sums of lyso-phosphatidylinositols and lyso-phosphatidylethanolamines, FFA 16:1/FFA 16:0, and FFA 18:1/FFA 18:0 were obviously higher in the pre-HD group than in the controls while they were significantly lower in patients after HD. These results indicated that UPLC-Q-TOF/MS-based lipidomics is a promising approach to investigate lipid alterations in relation to uremia and it is helpful to understand complex complications involved in HD patients.

  19. Lacidipine, a potential peroxynitrite scavenger: investigation of activity by liquid chromatography and mass spectrometry.

    PubMed

    Garzotti, Marco

    2003-01-01

    Inflamed tissues are often characterised by the production of *NO and O(2)(-) radicals, which are known to react at an extremely fast rate to produce peroxynitrite (ONOO(-)). This highly oxidising entity reacts with protein-bound tyrosine to give 3-nitrotyrosine, which is considered a biochemical marker of peroxynitrite-induced damage. Lacidipine is a calcium antagonist indicated for the treatment of mild to moderate hypertension. In the present work, electrospray mass spectrometry with and without liquid chromatography was used to evaluate the capability of lacidipine and two other related molecules as ONOO(-) scavengers. This capability is compared with that associated with a number of commercial polyphenols described in the literature as efficient scavengers of this cytotoxic agent. The use of mass spectrometry provided rapid quantitative assessment of both the nitration and its reduction, and showed that lacidipine possesses a reasonable capability for reducing in vitro nitration of superoxide dismutase.

  20. An unprecedented silver-decavanadate dimer investigated using ion-mobility mass spectrometry.

    PubMed

    McGlone, Thomas; Thiel, Johannes; Streb, Carsten; Long, De-Liang; Cronin, Leroy

    2012-01-11

    A silver(I)-linked decavanadate system has been synthesised, and characterised in both the solid-state and solution showing that two cluster units are held in a specific, dimeric arrangement wholly supported by cooperative hydrogen bonds, and ion-mobility mass spectrometry (IM-MS) was used to analyse the system yielding significant information on the secondary building units and aggregation behaviour supported by hydrogen bonding.

  1. Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction

    DOE PAGES

    Savee, John D.; Borkar, Sampada; Welz, Oliver; ...

    2015-05-18

    Here, the reaction of O(3P) + propyne (C3H4) was investigated at 298 K and 4 Torr using time-resolved multiplexed photoionization mass spectrometry and a synchrotron-generated tunable vacuum ultraviolet light source. The time-resolved mass spectra of the observed products suggest five major channels under our conditions: C2H3 + HCO, CH3 + HCCO, H + CH3CCO, C2H4 + CO, and C2H2 + H2 + CO. The relative branching ratios for these channels were found to be 1.00, (0.35 ± 0.11), (0.18 ± 0.10), (0.73 ± 0.27), and (1.31 ± 0.62). In addition, we observed signals consistent with minor production of C3H3 +more » OH and H2 + CH2CCO, although we cannot conclusively assign them as direct product channels from O(3P) + propyne. The direct abstraction mechanism plays only a minor role (≤1%), and we estimate that O(3P) addition to the central carbon of propyne accounts for 10% of products, with addition to the terminal carbon accounting for the remaining 89%. The isotopologues observed in experiments using d1-propyne (CH3CCD) and analysis of product branching in light of previously computed stationary points on the singlet and triplet potential energy surfaces (PESs) relevant to O(3P) + propyne suggest that, under our conditions, (84 ± 14)% of the observed product channels from O(3P) + propyne result from intersystem crossing from the initial triplet PES to the lower-lying singlet PES.« less

  2. Combustion of butanol isomers - A detailed molecular beam mass spectrometry investigation of their flame chemistry

    SciTech Connect

    Osswald, Patrick; Gueldenberg, Hanna; Kohse-Hoeinghaus, Katharina; Yang, Bin; Yuan, Tao; Qi, Fei

    2011-01-15

    The combustion chemistry of the four butanol isomers, 1-, 2-, iso- and tert-butanol was studied in flat, premixed, laminar low-pressure (40 mbar) flames of the respective alcohols. Fuel-rich ({phi} = 1.7) butanol-oxygen-(25%)argon flames were investigated using different molecular beam mass spectrometry (MBMS) techniques. Quantitative mole fraction profiles are reported as a function of burner distance. In total, 57 chemical compounds, including radical and isomeric species, have been unambiguously assigned and detected quantitatively in each flame using a combination of vacuum ultraviolet (VUV) photoionization (PI) and electron ionization (EI) MBMS. Synchrotron-based PI-MBMS allowed to separate isomeric combustion intermediates according to their different ionization thresholds. Complementary measurements in the same flames with a high mass-resolution EI-MBMS system provided the exact elementary composition of the involved species. Resulting mole fraction profiles from both instruments are generally in good quantitative agreement. In these flames of the four butanol isomers, temperature, measured by laser-induced fluorescence (LIF) of seeded nitric oxide, and major species profiles are strikingly similar, indicating seemingly analog global combustion behavior. However, significant variations in the intermediate species pool are observed between the fuels and discussed with respect to fuel-specific destruction pathways. As a consequence, different, fuel-specific pollutant emissions may be expected, by both their chemical nature and concentrations. The results reported here are the first of their kind from premixed isomeric butanol flames and are thought to be valuable for improving existing kinetic combustion models. (author)

  3. Ambient ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lebedev, A. T.

    2015-07-01

    Ambient ionization mass spectrometry emerged as a new scientific discipline only about ten years ago. A considerable body of information has been reported since that time. Keeping the sensitivity, performance and informativity of classical mass spectrometry methods, the new approach made it possible to eliminate laborious sample preparation procedures and triggered the development of miniaturized instruments to work directly in the field. The review concerns the theoretical foundations and design of ambient ionization methods. Their advantages and drawbacks, as well as prospects for application in chemistry, biology, medicine, environmetal analysis, etc., are discussed. The bibliography includes 194 references.

  4. Protein and Peptide Composition of Male Accessory Glands of Apis mellifera Drones Investigated by Mass Spectrometry.

    PubMed

    Gorshkov, Vladimir; Blenau, Wolfgang; Koeniger, Gudrun; Römpp, Andreas; Vilcinskas, Andreas; Spengler, Bernhard

    2015-01-01

    In honeybees, reproductive females usually mate early in their life with more than 10 males in free flight, often within 10 minutes, and then store male gametes for up to five years. Because of the extreme polyandry and mating in free flight special adaptations in males are most likely. We present here the results of an investigation of the protein content of four types of male reproductive glands from the Western honeybee (Apis mellifera) drone, namely seminal vesicles (secretion in ejaculate), as well as bulbus, cornua and mucus glands (secretions for the mating plug). Using high resolution and accuracy mass spectrometry and a combination of database searching and de novo sequencing techniques it was possible to identify 50 different proteins in total, inside all mentioned glands, except in the mucus gland. Most of the proteins are unique for a specific gland type, only one of them (H9KEY1/ATP synthase subunit O) was found in three glands, and 7 proteins were found in two types of glands. The identified proteins represent a wide variety of biological functions and can be assigned to several physiological classes, such as protection, energy generation, maintaining optimal conditions, associated mainly with vesicula seminalis; signaling, cuticle proteins, icarpin and apolipoproteins located mainly in the bulbus and cornua glands; and some other classes. Most of the discovered proteins were not found earlier during investigation of semen, seminal fluid and tissue of reproductive glands of the bee drone. Moreover, we provide here the origin of each protein. Thus, the presented data might shed light on the role of each reproductive gland.

  5. Protein and Peptide Composition of Male Accessory Glands of Apis mellifera Drones Investigated by Mass Spectrometry

    PubMed Central

    Gorshkov, Vladimir; Blenau, Wolfgang; Koeniger, Gudrun; Römpp, Andreas; Vilcinskas, Andreas; Spengler, Bernhard

    2015-01-01

    In honeybees, reproductive females usually mate early in their life with more than 10 males in free flight, often within 10 minutes, and then store male gametes for up to five years. Because of the extreme polyandry and mating in free flight special adaptations in males are most likely. We present here the results of an investigation of the protein content of four types of male reproductive glands from the Western honeybee (Apis mellifera) drone, namely seminal vesicles (secretion in ejaculate), as well as bulbus, cornua and mucus glands (secretions for the mating plug). Using high resolution and accuracy mass spectrometry and a combination of database searching and de novo sequencing techniques it was possible to identify 50 different proteins in total, inside all mentioned glands, except in the mucus gland. Most of the proteins are unique for a specific gland type, only one of them (H9KEY1/ATP synthase subunit O) was found in three glands, and 7 proteins were found in two types of glands. The identified proteins represent a wide variety of biological functions and can be assigned to several physiological classes, such as protection, energy generation, maintaining optimal conditions, associated mainly with vesicula seminalis; signaling, cuticle proteins, icarpin and apolipoproteins located mainly in the bulbus and cornua glands; and some other classes. Most of the discovered proteins were not found earlier during investigation of semen, seminal fluid and tissue of reproductive glands of the bee drone. Moreover, we provide here the origin of each protein. Thus, the presented data might shed light on the role of each reproductive gland. PMID:25955586

  6. In vivo investigation of homocysteine metabolism to polyamines by high-resolution accurate mass spectrometry and stable isotope labeling.

    PubMed

    Ruseva, Silviya; Lozanov, Valentin; Markova, Petia; Girchev, Radoslav; Mitev, Vanio

    2014-07-15

    Polyamines are essential polycations, playing important roles in mammalian physiology. Theoretically, the involvement of homocysteine in polyamine synthesis via S-adenosylmethionine is possible; however, to our knowledge, it has not been established experimentally. Here, we propose an original approach for investigation of homocysteine metabolites in an animal model. The method is based on the combination of isotope-labeled homocysteine supplementation and high-resolution accurate mass spectrometry analysis. Structural identity of the isotope-labeled metabolites was confirmed by accurate mass measurements of molecular and fragment ions and comparison of the retention times and tandem mass spectrometry fragmentation patterns. Isotope-labeled methionine, spermidine, and spermine were detected in all investigated plasma and tissue samples. The induction of moderate hyperhomocysteinemia leads to an alteration in polyamine levels in a different manner. The involvement of homocysteine in polyamine synthesis and modulation of polyamine levels could contribute to a better understanding of the mechanisms connected with homocysteine toxicity.

  7. [MALDI-TOF mass spectrometry in the investigation of large high-molecular biological compounds].

    PubMed

    Porubl'ova, L V; Rebriiev, A V; Hromovyĭ, T Iu; Minia, I I; Obolens'ka, M Iu

    2009-01-01

    MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight) mass spectrometry has become, in the recent years, a tool of choice for analyses of biological polymers. The wide mass range, high accuracy, informativity and sensitivity make it a superior method for analysis of all kinds of high-molecular biological compounds including proteins, nucleic acids and lipids. MALDI-TOF-MS is particularly suitable for the identification of proteins by mass fingerprint or microsequencing. Therefore it has become an important technique of proteomics. Furthermore, the method allows making a detailed analysis of post-translational protein modifications, protein-protein and protein-nucleic acid interactions. Recently, the method was also successfully applied to nucleic acid sequencing as well as screening for mutations.

  8. [Investigation of JinKui ShenQi pills by ultraviolet spectra and tandem mass spectrometry].

    PubMed

    Li, Wen-lan; Sun, Zhi; Cheng, Bin; Ji, Yu-bin; Bai, Jing

    2008-08-01

    On the base of establishing the fingerprint of JinKui ShenQi pills, the ultraviolet spectra-mass spectrometry/mass spectrometry, method was used to identify the fingerprint. Seperation was performed on the Symmetry Shield RP18 (5 microm, 4. 6 mm X 15 mm) analytical column with mobile phase consisting of 1% acetic acid and acetonitrile with gradient elute at the flow rate of 1.0 mL x min(-1), and the ultraviolet detection wavelength was set at 248 nm. Using the above-mentioned chromatographic condition, the fingerprint of different samples was established and the same fingerprint was defined. The fingerprints of different samples were compared with similarity evaluation software published by Pharmacopeia committee codex (2004A). The mass spectrograph with API-ESI ionization source was used, setting the flow rate at 0.5 mL x min(-1) after splitting stream. The pressure of atomization room was 50 Psi, the flow rate of dry gas was 9.0 L x min(-1), the capillary voltage was 4 kV, and the transmission voltage was 70 V. The negative scanner mode was chosen, scan scope was 100-2000, using ion trap to analyze quasimolecular ion peak and the selected fragment ion, and TIC chromatography and second order mass chromatogram were recorded. The major constituents among in JinKui ShenQi pills from different origins were separated well by HPLC. Although there was difference among different origins, they showed nineteen identical characteristic absorption bands. Three fingerprints chemical compositions such as loganin, cinnamal and paeonol were identified based on the retention time and ultraviolet spectra of standard preparation. According to their ultraviolet spectra, molecular weight and fragmentation information, ten peaks in the fingerprint were identified by ultraviolet spectroscopy-mass, spectrometry/massg spectrometry. They are 1,2,3-tri-O-galloyl-glucose, loganin, paeoniflorin, 1,2,3,6-tetro-O-galloyl-glucose, soya-cerebroside, cornuside, and PGG, benzoyl

  9. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  10. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  11. Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction

    SciTech Connect

    Savee, John D.; Borkar, Sampada; Welz, Oliver; Sztaray, Balint; Taatjes, Craig A.; Osborn, David L.

    2015-05-18

    Here, the reaction of O(3P) + propyne (C3H4) was investigated at 298 K and 4 Torr using time-resolved multiplexed photoionization mass spectrometry and a synchrotron-generated tunable vacuum ultraviolet light source. The time-resolved mass spectra of the observed products suggest five major channels under our conditions: C2H3 + HCO, CH3 + HCCO, H + CH3CCO, C2H4 + CO, and C2H2 + H2 + CO. The relative branching ratios for these channels were found to be 1.00, (0.35 ± 0.11), (0.18 ± 0.10), (0.73 ± 0.27), and (1.31 ± 0.62). In addition, we observed signals consistent with minor production of C3H3 + OH and H2 + CH2CCO, although we cannot conclusively assign them as direct product channels from O(3P) + propyne. The direct abstraction mechanism plays only a minor role (≤1%), and we estimate that O(3P) addition to the central carbon of propyne accounts for 10% of products, with addition to the terminal carbon accounting for the remaining 89%. The isotopologues observed in experiments using d1-propyne (CH3CCD) and analysis of product branching in light of previously computed stationary points on the singlet and triplet potential energy surfaces (PESs) relevant to O(3P) + propyne suggest that, under our conditions, (84 ± 14)% of the observed product channels from O(3P) + propyne result from intersystem crossing from the initial triplet PES to the lower-lying singlet PES.

  12. Imaging mass spectrometry in microbiology

    PubMed Central

    Watrous, Jeramie D.; Dorrestein, Pieter C.

    2013-01-01

    Mass spectrometry tools which allow for the 2-D visualization of the distribution of trace metals, metabolites, surface lipids, peptides and proteins directly from biological samples without the need for chemical tagging or antibodies are becoming increasingly useful for microbiology applications. These tools, comprised of different imaging mass spectrometry techniques, are ushering in an exciting new era of discovery by allowing for the generation of chemical hypotheses based on of the spatial mapping of atoms and molecules that can correlate to or transcend observed phenotypes. In this review, we explore the wide range of imaging mass spectrometry techniques available to microbiologists and describe their unique applications to microbiology with respect to the types of microbiology samples to be investigated. PMID:21822293

  13. Cocoa content influences chocolate molecular profile investigated by MALDI-TOF mass spectrometry.

    PubMed

    Bonatto, Cínthia C; Silva, Luciano P

    2015-06-01

    Chocolate authentication is a key aspect of quality control and safety. Matrix-assisted laser desorption ionization time-of flight (MALDI-TOF) mass spectrometry (MS) has been demonstrated to be useful for molecular profiling of cells, tissues, and even food. The present study evaluated if MALDI-TOF MS analysis on low molecular mass profile may classify chocolate samples according to the cocoa content. The molecular profiles of seven processed commercial chocolate samples were compared by using MALDI-TOF MS. Some ions detected exclusively in chocolate samples corresponded to the metabolites of cocoa or other constituents. This method showed the presence of three distinct clusters according to confectionery and sensorial features of the chocolates and was used to establish a mass spectra database. Also, novel chocolate samples were evaluated in order to check the validity of the method and to challenge the database created with the mass spectra of the primary samples. Thus, the method was shown to be reliable for clustering unknown samples into the main chocolate categories. Simple sample preparation of the MALDI-TOF MS approach described will allow the surveillance and monitoring of constituents during the molecular profiling of chocolates. © 2014 Society of Chemical Industry.

  14. Mass spectrometry with accelerators.

    PubMed

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  15. An Ion Mobility-Mass Spectrometry Investigation of Monocyte Chemoattractant Protein-1

    PubMed Central

    Schenauer, Matthew R.; Leary, Julie A.

    2009-01-01

    In the present article we describe the gas-phase dissociation behavior of the dimeric form of monocyte chemoattractant protein-1 (MCP-1) using quadrupole-traveling wave ion mobility-time of flight mass spectrometry (q-TWIMS-TOF MS) (Waters Synapt™). Through investigation of the 9+ charge state of the dimer, we were able to monitor dissociation product ion (monomer) formation as a function of activation energy. Using ion mobility, we were able to observe precursor ion structural changes occurring throughout the activation process. Arrival time distributions (ATDs) for the 5+ monomeric MCP-1 product ions, derived from the gas-phase dissociation of the 9+ dimer, were then compared with ATDs obtained for the 5+ MCP-1 monomer isolated directly from solution. The results show that the dissociated monomer is as compact as the monomer arising from solution, regardless of the trap collision energy (CE) used in the dissociation. The solution-derived monomer, when collisionally activated, also resists significant unfolding within measure. Finally, we compared the collisional activation data for the MCP-1 dimer with an MCP-1 dimer non-covalently bound to a single molecule of the semi-synthetic glycosaminoglycan (GAG) analog Arixtra™; the latter a therapeutic anti-thrombin III-activating pentasaccharide. We observed that while dimeric MCP-1 dissociated at relatively low trap CEs, the Arixtra-bound dimer required much higher energies, which also induced covalent bond cleavage in the bound Arixtra molecule. Both the free and Arixtra-bound dimers became less compact and exhibited longer arrival times with increasing trap CEs, albeit the Arixtra-bound complex at slightly higher energies. That both dimers shifted to longer arrival times with increasing activation energy, while the dissociated MCP-1 monomers remained compact, suggests that the longer arrival times of the Arixtra-free and Arixtra-bound dimers may represent a partial breach of non-covalent interactions between the

  16. Investigating the formation of "molybdenum blues" with gel electrophoresis and mass spectrometry.

    PubMed

    Nakamura, Ippei; Miras, Haralampos N; Fujiwara, Aya; Fujibayashi, Masaru; Song, Yu-Fei; Cronin, Leroy; Tsunashima, Ryo

    2015-05-27

    The reduction of solutions of acidified molybdate leads to the formation of a family of nanostructured molybdenum blue (MB) wheels which are linked together in a series of complex reaction networks. These networks are complex because the species which define the nodes are extremely labile, unstable, and common to many different networks. Herein, we combine gel electrophoresis and electrospray ionization mass spectrometry (ESI-MS) to investigate the effect of the pH and the ratio of reactants and reducing agents, R (R = [S2O4(2-)]/[MoO4(2-)]), on the complex underlying set of equilibria that make up MBs. By mapping the reaction parameter space given by experimental variables such as pH, R, solvent medium, and type of counterion, we show that the species present range from nanostructured MB wheels (comprising ca. 154 Mo atoms) to smaller molecular capsules, [(SO3)2Mo(V)2Mo(VI)16O54](6-) ({S2Mo18}), and templated hexameric [(μ6-SO3)Mo(V)6O15(μ2-SO3)3](8-)({S4Mo6}) anions. The parallel effects of templation and reduction on the self-assembly process are discussed, taking into consideration the Lewis basicity of the template, the oxidation state of the Mo centers, and the polarity of the reaction medium. Finally, we report a new type of molecular cage (TBA)5[Na(SO3)2(PhPO3)4Mo(V)4Mo(VI)14O49]·nMeCN (1), templated by SO3(2-) anions and decorated by organic ligands. This discovery results from the exploration of the cooperative effect of two anions possessing comparable Lewis basicity, and we believe this constitutes a new synthetic approach for the design of new nanostructured molecular metal oxides and will lead to a greater understanding of the complex reaction networks underpinning the assembly of this family of nanoclusters.

  17. Investigation by Imaging Mass Spectrometry of Biomarker Candidates for Aging in the Hair Cortex

    PubMed Central

    Waki, Michihiko Luca; Onoue, Kenji; Takahashi, Tsukasa; Goto, Kensuke; Saito, Yusuke; Inami, Katsuaki; Makita, Ippei; Angata, Yurika; Suzuki, Tomomi; Yamashita, Mihi; Sato, Narumi; Nakamura, Saki; Yuki, Dai; Sugiura, Yuki; Zaima, Nobuhiro; Goto-Inoue, Naoko; Hayasaka, Takahiro; Shimomura, Yutaka; Setou, Mitsutoshi

    2011-01-01

    Background Human hair is one of the essential components that define appearance and is a useful source of samples for non-invasive biomonitoring. We describe a novel application of imaging mass spectrometry (IMS) of hair biomolecules for advanced molecular characterization and a better understanding of hair aging. As a cosmetic and biomedical application, molecules whose levels in hair altered with aging were comprehensively investigated. Methods Human hair was collected from 15 young (20±5 years old) and 15 older (50±5 years old) volunteers. Matrix-free laser desorption/ionization IMS was used to visualize molecular distribution in the hair sections. Hair-specific ions displaying a significant difference in the intensities between the 2 age groups were extracted as candidate markers for aging. Tissue localization of the molecules and alterations in their levels in the cortex and medulla in the young and old groups were determined. Results Among the 31 molecules detected specifically in hair sections, 2—one at m/z 153.00, tentatively assigned to be dihydrouracil, and the other at m/z 207.04, identified to be 3,4-dihydroxymandelic acid (DHMA)—exhibited a higher signal intensity in the young group than in the old, and 1 molecule at m/z 164.00, presumed to be O-phosphoethanolamine, displayed a higher intensity in the old group. Among the 3, putative O-phosphoethanolamine showed a cortex-specific distribution. The 3 molecules in cortex presented the same pattern of alteration in signal intensity with aging, whereas those in medulla did not exhibit significant alteration. Conclusion Three molecules whose levels in hair altered with age were extracted. While they are all possible markers for aging, putative dihydrouracil and DHMA, are also suspected to play a role in maintaining hair properties and could be targets for cosmetic supplementation. Mapping of ion localization in hair by IMS is a powerful method to extract biomolecules in specified regions and determine

  18. Desorption in Mass Spectrometry.

    PubMed

    Usmanov, Dilshadbek Tursunbayevich; Ninomiya, Satoshi; Chen, Lee Chuin; Saha, Subhrakanti; Mandal, Mridul Kanti; Sakai, Yuji; Takaishi, Rio; Habib, Ahsan; Hiraoka, Kenzo; Yoshimura, Kentaro; Takeda, Sen; Wada, Hiroshi; Nonami, Hiroshi

    2017-01-01

    In mass spectrometry, analytes must be released in the gas phase. There are two representative methods for the gasification of the condensed samples, i.e., ablation and desorption. While ablation is based on the explosion induced by the energy accumulated in the condensed matrix, desorption is a single molecular process taking place on the surface. In this paper, desorption methods for mass spectrometry developed in our laboratory: flash heating/rapid cooling, Leidenfrost phenomenon-assisted thermal desorption (LPTD), solid/solid friction, liquid/solid friction, electrospray droplet impact (EDI) ionization/desorption, and probe electrospray ionization (PESI), will be described. All the methods are concerned with the surface and interface phenomena. The concept of how to desorb less-volatility compounds from the surface will be discussed.

  19. Desorption in Mass Spectrometry

    PubMed Central

    Usmanov, Dilshadbek Tursunbayevich; Ninomiya, Satoshi; Chen, Lee Chuin; Saha, Subhrakanti; Mandal, Mridul Kanti; Sakai, Yuji; Takaishi, Rio; Habib, Ahsan; Hiraoka, Kenzo; Yoshimura, Kentaro; Takeda, Sen; Wada, Hiroshi; Nonami, Hiroshi

    2017-01-01

    In mass spectrometry, analytes must be released in the gas phase. There are two representative methods for the gasification of the condensed samples, i.e., ablation and desorption. While ablation is based on the explosion induced by the energy accumulated in the condensed matrix, desorption is a single molecular process taking place on the surface. In this paper, desorption methods for mass spectrometry developed in our laboratory: flash heating/rapid cooling, Leidenfrost phenomenon-assisted thermal desorption (LPTD), solid/solid friction, liquid/solid friction, electrospray droplet impact (EDI) ionization/desorption, and probe electrospray ionization (PESI), will be described. All the methods are concerned with the surface and interface phenomena. The concept of how to desorb less-volatility compounds from the surface will be discussed. PMID:28337398

  20. Biological Cluster Mass Spectrometry

    PubMed Central

    Winograd, Nicholas; Garrison, Barbara J.

    2010-01-01

    This article reviews the new physics and new applications of secondary ion mass spectrometry using cluster ion probes. These probes, particularly C60, exhibit enhanced molecular desorption with improved sensitivity owing to the unique nature of the energy-deposition process. In addition, these projectiles are capable of eroding molecular solids while retaining the molecular specificity of mass spectrometry. When the beams are microfocused to a spot on the sample, bioimaging experiments in two and three dimensions are feasible. We describe emerging theoretical models that allow the energy-deposition process to be understood on an atomic and molecular basis. Moreover, experiments on model systems are described that allow protocols for imaging on biological materials to be implemented. Finally, we present recent applications of imaging to biological tissue and single cells to illustrate the future directions of this methodology. PMID:20055679

  1. MASS SPECTROMETRY IN ENVIRONMENTAL SCIENCES

    EPA Science Inventory

    This review covers applications of mass spectrometry to the environmental sciences. From the early applications of mass spectrometry to environmental research in the 1960s and 1970s, mass spectrometry has played an important role in aiding our understanding of environmental poll...

  2. MASS SPECTROMETRY IN ENVIRONMENTAL SCIENCES

    EPA Science Inventory

    This review covers applications of mass spectrometry to the environmental sciences. From the early applications of mass spectrometry to environmental research in the 1960s and 1970s, mass spectrometry has played an important role in aiding our understanding of environmental poll...

  3. Hybrid instruments for mass spectrometry/mass spectrometry

    SciTech Connect

    Glish, G.L.; McLuckey, S.A.

    1986-01-01

    In order to refine further the technique of mass spectrometry/mass spectrometry efforts are being made to combine the desirable features of sector based tandem instruments with those of triple quadrupole mass spectrometers. This has resulted in the construction of tandem mass spectrometers which incorporate both sector type analyzers and quadrupole mass filters. These so-called hybrid instruments, designed specifically for mass spectrometry/mass spectrometry applications, are appearing in a variety of geometries each with unique features. This review describes the hybrid instruments reported to data and discusses general considerations for evaluating hybrid instruments with regard to application. 100 references.

  4. Investigation of the metabolism of ergot alkaloids in cell culture by fourier transformation mass spectrometry.

    PubMed

    Mulac, Dennis; Grote, Anna-Karina; Kleigrewe, Karin; Humpf, Hans-Ulrich

    2011-07-27

    Ergot alkaloids are known toxic secondary metabolites of the fungus Claviceps purpurea occurring in various grains, especially rye products. The liver is responsible for converting the ergot alkaloids into metabolites; however, the toxic impact of these end products of metabolism is still unknown. The aim of this study was to analyze the metabolism of ergot alkaloids in colon and liver cell lines (HT-29, HepG2), as well as in human primary renal cells (RPTEC). It was shown that cells in vitro are able to metabolize ergot alkaloids, forming a variety of metabolic compounds. Significant differences between the used cell types could be identified, and a suitable model system was established using HT-29 cells, performing an intensive metabolism to hydroxylated metabolites. The formed substances were analyzed by coupling of high-performance liquid chromatography with fluorescence detection and Fourier transformation mass spectrometry (HPLC-FLD-FTMS) as a powerful tool to identify known and unknown metabolites.

  5. Investigating the Transformations of Polyoxoanions Using Mass Spectrometry and Molecular Dynamics.

    PubMed

    Cameron, Jamie M; Vilà-Nadal, Laia; Winter, Ross S; Iijima, Fumichika; Murillo, Juan Carlos; Rodríguez-Fortea, Antonio; Oshio, Hiroki; Poblet, Josep M; Cronin, Leroy

    2016-07-20

    The reactions of [γ-SiW10O36](8-) represent one of the most important synthetic gateways into a vast array of polyoxotungstate chemistry. Herein, we set about exploring the transformation of the lacunary polyoxoanion [β2-SiW11O39](8-) into [γ-SiW10O36](8-) using high-resolution electrospray mass spectrometry, density functional theory, and molecular dynamics. We show that the reaction proceeds through an unexpected {SiW9} precursor capable of undertaking a direct β → γ isomerization via a rotational transformation. The remarkably low-energy transition state of this transformation could be identified through theoretical calculations. Moreover, we explore the significant role of the countercations for the first time in such studies. This combination of experimental and the theoretical studies can now be used to understand the complex chemical transformations of oxoanions, leading to the design of reactivity by structural control.

  6. MASS SPECTROMETRY-BASED METABOLOMICS

    PubMed Central

    Dettmer, Katja; Aronov, Pavel A.; Hammock, Bruce D.

    2007-01-01

    This review presents an overview of the dynamically developing field of mass spectrometry-based metabolomics. Metabolomics aims at the comprehensive and quantitative analysis of wide arrays of metabolites in biological samples. These numerous analytes have very diverse physico-chemical properties and occur at different abundance levels. Consequently, comprehensive metabolomics investigations are primarily a challenge for analytical chemistry and specifically mass spectrometry has vast potential as a tool for this type of investigation. Metabolomics require special approaches for sample preparation, separation, and mass spectrometric analysis. Current examples of those approaches are described in this review. It primarily focuses on metabolic fingerprinting, a technique that analyzes all detectable analytes in a given sample with subsequent classification of samples and identification of differentially expressed metabolites, which define the sample classes. To perform this complex task, data analysis tools, metabolite libraries, and databases are required. Therefore, recent advances in metabolomics bioinformatics are also discussed. PMID:16921475

  7. "Magic" Ionization Mass Spectrometry.

    PubMed

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.

  8. "Magic" Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The "magic" that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.

  9. Microdosing studies using accelerated mass spectrometry as exploratory investigational new drug trials.

    PubMed

    Bae, Soo Kyung; Shon, Ji-Hong

    2011-11-01

    Innovative attempts have been made to overcome nonproductivity and high expenditure in the clinical stages of new drug development. Microdosing studies using subpharmacological doses provide early insight into the body's disposition toward candidate compounds, and are innovative exploratory trials that can promote productivity in drug development. Highly sensitive analytical technology is crucial in microdosing studies that employ qualitative and quantitative assays of target materials in humans. Accelerator mass spectrometry (AMS) has facilitated the adoption of a human microdosing study in the early phase of clinical drug development. Results derived from AMS microdosing studies using labeled compounds can provide various types of information for candidate selection, including pharmacokinetic characteristics and metabolic profiles of candidate compounds. The applicability of microdosing studies is currently expanding into absolute bioavailability and mass balance studies. Although it remains uncertain whether microdosing adequately predicts the pharmacokinetics of therapeutic doses, further development of microdosing studies using AMS may benefit the field of new drug development and could pose a new challenge to researchers. The use of advanced technology in candidate selection will contribute to improved productivity and competitiveness in pharmaceutical research and development. The introduction of microdosing studies using AMS in Korea will present a newly applicable method for innovative clinical trials and contribute to development potential in global competition.

  10. Investigation of isovaline enantiomeric excesses in CM meteorites using liquid chromatography time of flight mass spectrometry

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Dworkin, Jason P.

    2003-01-01

    The enantiomeric abundances of the alpha-dialkyl amino acid isovaline were measured in the CM2 meteorites Murchison and LEW 90500 using a new liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS) technique coupled with OPA/NAC derivatization and UV fluorescence detection. Previous analyses of Murchison have shown that L-enantiomeric excesses of isovaline range from 0 to 15.2% with significant variation between meteorite fragments [1]. For this study, hot water extracts of interior fragments (> 2 cm from fusion crust) of the Murchison (USNM 6650.2, mass 6 g) and LEW 90500 (split 69, parent 1, mass 5 g) carbonaceous meteorites were analyzed. Enantiomeric excesses were measured using the single ion LC-ToF-MS trace for the OPA/NAC derivative of isovaline at d z 393.15 (Fig. 1). L-isovaline excesses in these meteorite samples ranged from 18.9 to 20.5% for Murchison and -0.5 to 3.0% for LEW 90500. The measured values for Murchison are the largest enantiomeric excesses for isovaline reported to date. The enantiomeric excesses of L-isovaline cannot be the result of interference from other C5 amino acid isomers present in the meteorites or terrestrial contamination from the landing site environments. The L-isovaline excesses in Murchison are inconsistent with the synthesis of all of the isovaline by the Strecker-cyanohydrin pathway on the CM meteorite parent body. The mechanism(s) for the formation of the enantiomeric asymmetry in isovaline in Murchison are currently unknown and it is not clear how the asymmetry of alpha-dialkyl amino acids could be transferred to the a-hydrogen protein amino acids common in all life on Earth today.

  11. Investigation of isovaline enantiomeric excesses in CM meteorites using liquid chromatography time of flight mass spectrometry

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Dworkin, Jason P.

    2003-01-01

    The enantiomeric abundances of the alpha-dialkyl amino acid isovaline were measured in the CM2 meteorites Murchison and LEW 90500 using a new liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS) technique coupled with OPA/NAC derivatization and UV fluorescence detection. Previous analyses of Murchison have shown that L-enantiomeric excesses of isovaline range from 0 to 15.2% with significant variation between meteorite fragments [1]. For this study, hot water extracts of interior fragments (> 2 cm from fusion crust) of the Murchison (USNM 6650.2, mass 6 g) and LEW 90500 (split 69, parent 1, mass 5 g) carbonaceous meteorites were analyzed. Enantiomeric excesses were measured using the single ion LC-ToF-MS trace for the OPA/NAC derivative of isovaline at d z 393.15 (Fig. 1). L-isovaline excesses in these meteorite samples ranged from 18.9 to 20.5% for Murchison and -0.5 to 3.0% for LEW 90500. The measured values for Murchison are the largest enantiomeric excesses for isovaline reported to date. The enantiomeric excesses of L-isovaline cannot be the result of interference from other C5 amino acid isomers present in the meteorites or terrestrial contamination from the landing site environments. The L-isovaline excesses in Murchison are inconsistent with the synthesis of all of the isovaline by the Strecker-cyanohydrin pathway on the CM meteorite parent body. The mechanism(s) for the formation of the enantiomeric asymmetry in isovaline in Murchison are currently unknown and it is not clear how the asymmetry of alpha-dialkyl amino acids could be transferred to the a-hydrogen protein amino acids common in all life on Earth today.

  12. Mass spectrometry and renal calculi

    PubMed Central

    Purcarea, VL; Sisu, I; Sisu, E

    2010-01-01

    The present review represents a concise and complete survey of the literature covering 2004–2009, concerning the mass spectrometric techniques involved in the structural investigation of renal calculi. After a short presentation of the fundamental mass spectrometric techniques (MALDI–TOF, QTOF, MS–MS) as well as hyphenated methods (GC–MS, LC–MS, CE–MS), an extensive study of the urinary proteome analysis as well as the detection and quantification by mass spectrometry of toxins, drugs and metabolites from renal calculi is presented. PMID:20968197

  13. Investigation of an enhanced resolution triple quadrupole mass spectrometer for high-throughput liquid chromatography/tandem mass spectrometry assays.

    PubMed

    Yang, Liyu; Amad, Ma'an; Winnik, Witold M; Schoen, Alan E; Schweingruber, Hans; Mylchreest, Iain; Rudewicz, Patrick J

    2002-01-01

    Triple quadrupole mass spectrometers, when operated in multiple reaction monitoring (MRM) mode, offer a unique combination of sensitivity, specificity, and dynamic range. Consequently, the triple quadrupole is the workhorse for high-throughput quantitation within the pharmaceutical industry. However, in the past, the unit mass resolution of quadrupole instruments has been a limitation when interference from matrix or metabolites cannot be eliminated. With recent advances in instrument design, triple quadrupole instruments now afford mass resolution of less than 0.1 Dalton (Da) full width at half maximum (FWHM). This paper describes the evaluation of an enhanced resolution triple quadrupole mass spectrometer for high-throughput bioanalysis with emphasis on comparison of selectivity, sensitivity, dynamic range, precision, accuracy, and stability under both unit mass (1 Da FWHM) and enhanced (mass resolution, the transmitted precursor ion from the first quadrupole contained not only protonated molecules from mometasone, but also PPG interference. At enhanced resolution only selected mometasone peaks were transmitted, and no interference from PPG was detected. Sensitivity of the instrument was demonstrated with 10 femtograms of descarboethoxyloratadine injected on-column, for which a signal-to-noise (S/N) ratio of 24 was obtained for MRM chromatograms at both unit and enhanced resolution. Absolute signals obtained at enhanced resolution were about one-third those obtained at unit mass resolution. However, S/N was maintained at enhanced resolution due to the proportional decrease in noise level. Finally, the stability of the instrument operating at enhanced resolution was demonstrated during an overnight 17 h period that was used to validate a liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for

  14. Investigating nephrotoxicity of polymyxin derivatives by mapping renal distribution using mass spectrometry imaging.

    PubMed

    Nilsson, Anna; Goodwin, Richard J A; Swales, John G; Gallagher, Richard; Shankaran, Harish; Sathe, Abhishek; Pradeepan, Selvi; Xue, Aixiang; Keirstead, Natalie; Sasaki, Jennifer C; Andren, Per E; Gupta, Anshul

    2015-09-21

    Colistin and polymyxin B are effective treatment options for Gram-negative resistant bacteria but are used as last-line therapy due to their dose-limiting nephrotoxicity. A critical factor in developing safer polymyxin analogues is understanding accumulation of the drugs and their metabolites, which is currently limited due to the lack of effective techniques for analysis of these challenging molecules. Mass spectrometry imaging (MSI) allows direct detection of targets (drugs, metabolites, and endogenous compounds) from tissue sections. The presented study exemplifies the utility of MSI by measuring the distribution of polymyxin B1, colistin, and polymyxin B nonapeptide (PMBN) within dosed rat kidney tissue sections. The label-free MSI analysis revealed that the nephrotoxic compounds (polymyxin B1 and colistin) preferentially accumulated in the renal cortical region. The less nephrotoxic analogue, polymyxin B nonapeptide, was more uniformly distributed throughout the kidney. In addition, metabolites of the dosed compounds were detected by MSI. Kidney homogenates were analyzed using LC/MS/MS to determine total drug exposure and for metabolite identification. To our knowledge, this is the first time such techniques have been utilized to measure the distribution of polymyxin drugs and their metabolites. By simultaneously detecting the distribution of drug and drug metabolites, MSI offers a powerful alternative to tissue homogenization analysis and label or antibody-based imaging.

  15. Calculating Relative Ionization Probabilities of Plutonium for Resonance Ionization Mass Spectrometry to Support Nuclear Forensic Investigations

    NASA Astrophysics Data System (ADS)

    Lensegrav, Craig; Smith, Craig; Isselhardt, Brett

    2015-03-01

    Ongoing work seeks to apply the technology of Resonance Ionization Mass Spectrometry (RIMS) to problems related to nuclear forensics and, in particular, to the analysis and quantification of debris from nuclear detonations. As part of this effort, modeling and simulation methods are being applied to analyze and predict the potential for ionization by laser excitation of isotopes of both uranium and plutonium. Early work focused on the ionization potential of isotopes of uranium, and the present effort has expanded and extended the previous work by identifying and integrating new data for plutonium isotopes. In addition to extending the effort to this important new element, we have implemented more accurate descriptions of the spatial distribution of the laser beams to improve the accuracy of model predictions compared with experiment results as well as an ability to readily incorporate new experimental data as they become available. The model is used to estimate ionization cross sections and to compare relative excitation on two isotopes as a function of wavelength. This allows the study of sensitivity of these measurements to fluctuations in laser wavelength, irradiance, and bandwidth. We also report on initial efforts to include predictions of americium ionization probabilities into our modeling package. I would like to thank my co-authors, Gamani Karunasiri and Fabio Alves. My success is a product of their support and guidance.

  16. An investigation of a nosocomial outbreak of Clostridium difficile by pyrolysis mass spectrometry.

    PubMed

    Magee, J T; Brazier, J S; Hosein, I K; Ribeiro, C D; Hill, D W; Griffiths, A; Da Costa, C; Sinclair, A J; Duerden, B I

    1993-11-01

    Isolates from a presumptive nosocomial outbreak of Clostridium difficile infection at a large teaching hospital were typed by pyrolysis mass spectrometry (PMS) and antibiograms. One isolate, from the putative index case, was dissimilar from the outbreak strain, but 24 isolates from 16 patients were indistinguishable by both methods. The outbreak centred on two wards for the acute care of the elderly, with a few cases elsewhere. Transfer of patients appeared to be the route of transmission between wards. There was a significant fall in the incidence of cases following intervention by the Infection Control Unit. This included ward inspection, advice on antibiotic usage and advice on prevention of faecal-oral transfer, particularly by proper handwashing. Subsequent monitoring of C. difficile infection showed a background of sporadic, dissimilar isolates with occasional apparent cross-infection incidents limited to a few patients. In suspected outbreaks, patterns of antibiotic susceptibility may be useful in initial screening, before referral for more sophisticated typing. There was excellent correlation between PMS results, antibiograms and epidemiological information.

  17. Investigating the Transformations of Polyoxoanions Using Mass Spectrometry and Molecular Dynamics

    PubMed Central

    2016-01-01

    The reactions of [γ-SiW10O36]8– represent one of the most important synthetic gateways into a vast array of polyoxotungstate chemistry. Herein, we set about exploring the transformation of the lacunary polyoxoanion [β2-SiW11O39]8– into [γ-SiW10O36]8– using high-resolution electrospray mass spectrometry, density functional theory, and molecular dynamics. We show that the reaction proceeds through an unexpected {SiW9} precursor capable of undertaking a direct β → γ isomerization via a rotational transformation. The remarkably low-energy transition state of this transformation could be identified through theoretical calculations. Moreover, we explore the significant role of the countercations for the first time in such studies. This combination of experimental and the theoretical studies can now be used to understand the complex chemical transformations of oxoanions, leading to the design of reactivity by structural control. PMID:27321042

  18. Single event mass spectrometry

    DOEpatents

    Conzemius, Robert J.

    1990-01-16

    A means and method for single event time of flight mass spectrometry for analysis of specimen materials. The method of the invention includes pulsing an ion source imposing at least one pulsed ion onto the specimen to produce a corresponding emission of at least one electrically charged particle. The emitted particle is then dissociated into a charged ion component and an uncharged neutral component. The ion and neutral components are then detected. The time of flight of the components are recorded and can be used to analyze the predecessor of the components, and therefore the specimen material. When more than one ion particle is emitted from the specimen per single ion impact, the single event time of flight mass spectrometer described here furnis This invention was made with Government support under Contract No. W-7405-ENG82 awarded by the Department of Energy. The Government has certain rights in the invention.

  19. Metabonomics investigation of human urine after ingestion of green tea with gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and (1)H NMR spectroscopy.

    PubMed

    Law, Wai Siang; Huang, Pei Yun; Ong, Eng Shi; Ong, Choon Nam; Li, Sam Fong Yau; Pasikanti, Kishore Kumar; Chan, Eric Chun Yong

    2008-08-01

    A method using gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and (1)H NMR with pattern recognition tools such as principle components analysis (PCA) was used to study the human urinary metabolic profiles after the intake of green tea. From the normalized peak areas obtained from GC/MS and LC/MS and peak heights from (1)H NMR, statistical analyses were used in the identification of potential biomarkers. Metabolic profiling by GC/MS provided a different set of quantitative signatures of metabolites that can be used to characterize the molecular changes in human urine samples. A comparison of normalized metabonomics data for selected metabolites in human urine samples in the presence of potential overlapping peaks after tea ingestion from LC/MS and (1)H NMR showed the reliability of the current approach and method of normalization. The close agreements of LC/MS with (1)H NMR data showed that the effects of ion suppression in LC/MS for early eluting metabolites were not significant. Concurrently, the specificity of detecting the stated metabolites by (1)H NMR and LC/MS was demonstrated. Our data showed that a number of metabolites involved in glucose metabolism, citric acid cycle and amino acid metabolism were affected immediately after the intake of green tea. The proposed approach provided a more comprehensive picture of the metabolic changes after intake of green tea in human urine. The multiple analytical approach together with pattern recognition tools is a useful platform to study metabolic profiles after ingestion of botanicals and medicinal plants.

  20. Proteomic investigation of human burn wounds by 2D-difference gel electrophoresis and mass spectrometry

    PubMed Central

    Pollins, Alonda C.; Friedman, David B.; Nanney, Lillian B.

    2009-01-01

    Background In humans, thermal cutaneous injury represents a serious traumatic event that induces a host of dynamic alterations. Unfortunately the molecular mechanisms that underlie these serious perturbations remain poorly understood. We applied a global analysis method to identify dynamically changing proteins within the burn environment, which could eventually become biomarkers or targets for treatment. Materials and Methods Protein extracts of normal/unwounded skin and burn wounds were assayed by 2D difference gel electrophoresis (DIGE), a proteomic technology by which abundance levels of intact proteins (including isoforms) were simultaneously quantified from multiple samples with statistical confidence. Through unsupervised multivariate principal component analysis, protein expression patterns from individual samples were appropriately clustered into their correct temporal healing periods grouped into postburn periods of 1–3 days, 4–6 days or 7–10 days after injury. Forty-six proteins were subsequently selected for identification by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Results Proteins identified with differential temporal patterns of expression included predictable cytoskeletal proteins such as vimentin, and keratins 1, 5, 6, 16, and 17. Other candidate proteins with potential involvement in healing included HSP90, members of the serpin family (Serpin B1, SCCA1 & 2), haptoglobin, gelsolin, eIF4A1, IQGAP1, and TCTP. Conclusions We have utilized the combined technique, DIGE/MS, to capture new insights into cutaneous responses to burn trauma and subsequent processes of early wound healing in humans. This pilot study provides a proteomic snapshot of temporal events that can be used to weave together the interconnected processes that define the response to serious cutaneous injury. PMID:17604053

  1. Isotope dilution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Heumann, Klaus G.

    1992-09-01

    In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of

  2. Imaging Mass Spectrometry in Neuroscience

    PubMed Central

    2013-01-01

    Imaging mass spectrometry is an emerging technique of great potential for investigating the chemical architecture in biological matrices. Although the potential for studying neurobiological systems is evident, the relevance of the technique for application in neuroscience is still in its infancy. In the present Review, a principal overview of the different approaches, including matrix assisted laser desorption ionization and secondary ion mass spectrometry, is provided with particular focus on their strengths and limitations for studying different neurochemical species in situ and in vitro. The potential of the various approaches is discussed based on both fundamental and biomedical neuroscience research. This Review aims to serve as a general guide to familiarize the neuroscience community and other biomedical researchers with the technique, highlighting its great potential and suitability for comprehensive and specific chemical imaging. PMID:23530951

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  4. Time-resolved measurements with single droplet introduction to investigate space-charge effects in plasma mass spectrometry.

    PubMed

    Stewart, I I; Olesik, J W

    1999-02-01

    An investigation of the space-charge induced effects of high concentrations of Pb+ matrix ions on Li+ analyte ions in inductively coupled plasma mass spectrometry (ICP-MS) is presented using a vertically oriented mass spectrometer with single droplet introduction. Greater reproducibility and stability in droplet-to-droplet sample introduction using the monodisperse microparticulate injector (MDMI) was achieved with the vertical orientation. Typical variation (%RSD) in the droplet-to-droplet arrival times, and mass spectrometry peak analytical areas are better than 5%. With this precision, a more quantitative description of the space-charge effect on a single cloud of ions is obtained. Both radial and axial space-charge effects were found to occur in the ion beam. Radial effects result in a loss in intensity because of poor transmission or collisions at surfaces within the mass spectrometer. Axial effects modify the kinetic energy distribution of background ion beam components (e.g., 16O+ and 40Ar+) and sampled ion cloud constituents (e.g., 7Li+). However, axial effects do not appear to generate significant broadening of sampled ion clouds within the mass spectrometer. At the point of charge separation and high ion-beam charge density, the ion cloud maxima for Li and Pb are not coincident. This is because of mass dependent diffusion in the ICP as the ion clouds approach the sampling orifice. Space-charge induced ion loss occurs predominantly at a localized region after the Li+ sampled cloud peak maximum. When the Pb concentration in the sample is sufficiently high the 7Li+ sampled signal has a bimodal peak shape. The existence of the dip and its relative location in the bimodal 7Li+ sampled signal suggests that space-charge effects are localized to the region of high charge density occurring just after charge separation.

  5. Mass spectrometry and tandem mass spectrometry of citrus limonoids.

    PubMed

    Tian, Qingguo; Schwartz, Steven J

    2003-10-15

    Methods for atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) of citrus limonoid aglycones and electrospray ionization tandem mass spectrometry (ESI-MS/MS) of limonoid glucosides are reported. The fragmentation patterns of four citrus limonoid aglycones (limonin, nomilin, obacunone, and deacetylnomilin) and six limonoid glucosides, that is, limonin 17-beta-D-glucopyranoside (LG), nomilin 17-beta-D-glucopyranoside (NG), nomilinic acid 17-beta-D-glucopyranoside (NAG), deacetyl nomilinic acid 17-beta-D-glucopyranoside (DNAG), obacunone 17-beta-D-glucopyranoside (OG), and obacunoic acid 17-beta-D-glucopyranoside (OAG) were investigated using a quadruple mass spectrometer in low-energy collisionally activated dissociation (CAD). The four limonoid aglycones and four limonoid glucosides (LG, OG, NAG, and DNAG) were purified from citrus seeds; the other two limonoid glucosides (NG and OAG) were tentatively identified in the crude extract of grapefruit seeds by ESI mass spectrometry in both positive and negative ion analysis. Ammonium hydroxide or acetic acid was added to the mobile phase to facilitate ionization. During positive ion APCI analysis of limonoid aglycones, protonated molecular ion, [M + H]+, or adduct ion, [M + NH3 + H]-, was formed as base peaks when ammonium hydroxide was added to the mobile phase. Molecular anions or adduct ions with acetic acid ([M + HOAc - H] and [M + HOAc]-) or a deprotonated molecular ion were produced during negative ion APCI analysis of limonoid aglycones, depending on the mobile-phase modifier used. Positive ion ESI-MS of limonoid glucosides produced adduct ions of [M + H + NH3]+, [M + Na]+, and [M + K]+ when ammonium hydroxide was added to the mobile phase. After collisionally activated dissociation (CAD) of the limonoid aglycone molecular ions in negative ion APCI analysis, fragment ions indicated structural information of the precursor ions, showing the presence of methyl, carboxyl, and oxygenated ring

  6. Analytical strategy to investigate 3,4-methylenedioxypyrovalerone (MDPV) metabolites in consumers' urine by high-resolution mass spectrometry.

    PubMed

    Ibáñez, María; Pozo, Óscar J; Sancho, Juan V; Orengo, Teresa; Haro, Gonzalo; Hernández, Félix

    2016-01-01

    The potential of high-resolution mass spectrometry (HRMS) for the investigation of human in vivo metabolism of 3,4-methylenedioxypyrovalerone (MDPV) using urine collected from a consumer (this is, in non-controlled experiments) has been investigated. As a control sample was not available, the common approach based on the comparison of a control/blank sample and samples collected after drug intake could not be used. Alternatively, an investigation based on common fragmentation pathways was applied, assuming that most metabolites share some fragments with the parent drug. An extension of this approach was also applied based on the fragmentation pathway of those metabolites identified in urine samples in the first step. The use of MS(E) experiments (sequential acquisition of mass spectra at low and high collision energy) has been crucial to this aim as it allowed promoting fragmentation in the collision cell without any previous precursor ion selection. MDPV belongs to the group of new psychoactive substances (NPS), being known as the "cannibal drug". This substance is being abused more and more and is associated with dangerous side effects. The human metabolites (both phase I and phase II) were detected and tentatively identified by accurate mass full-spectrum measurements using ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Following this strategy, up to 10 phase I metabolites, together with some glucuronides and sulphates, were detected and tentative structures were proposed. Several compounds identified in this work have not been previously reported in the literature.

  7. Investigation of lanthanum-strontium-cobalt ferrites using laser ablation inductively coupled plasma-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Óvári, Mihály; Tarsoly, Gergely; Németh, Zoltán; Mihucz, Victor G.; Záray, Gyula

    2017-01-01

    In the present study, suitability of laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for characterization of the purity and homogeneity of lanthanum-strontium-cobalt ferrite (LSCF) ceramic microsamples with general formula La1 - xSrxFe0.025Co0.975O3 (0.00 ≤ x ≤ 0.50) was studied through determination of their Sr:La ratios as well as Sr content either in depth or line profiling mode. The Sr content of the LSCF samples expressed as weight percent ranged between 5.8% and 9.7% in the case of wet chemical ICP-MS analysis, while theoretical values varied from 5.5% to 9.4%. In the case of LA-ICP-MS, relative standard deviation of the La-normalized Sr intensities was sufficient to characterize the homogeneity of the studied samples. Major and trace element (Mn, Ni, Cu, Mg, Al, Ba) concentrations could be detected at medium resolution of the applied sector field ICP-MS instrument after microwave-assisted acid digestion. For depth and line profiling, a successful approach consisted of the normalization of intensities of Sr, Fe and Co with the corresponding La counts. For the determination of the elemental ratios of La and Sr, the methods involving LA were in good agreement with theoretical values by standardization to an in-house standard corresponding to the LSCF sample having the highest x value (i.e., 0.50) checked by wet chemical ICP-MS measurements. Thus, assessment of fine scale doping of synthesized perovskite type of microsamples could be achieved by the proposed LA-ICP-MS based on a novel calibration approach applying an in-house perovskite standard. Therefore, LA-ICP-MS can be recommended for quality control of perovskite-based products. In memoriam Attila Vértes (1934-2011), full professor of the Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.

  8. Application of mass spectrometry to hair analysis for forensic toxicological investigations.

    PubMed

    Vincenti, Marco; Salomone, Alberto; Gerace, Enrico; Pirro, Valentina

    2013-01-01

    The increasing role of hair analysis in forensic toxicological investigations principally owes to recent improvements of mass spectrometric instrumentation. Research achievements during the last 6 years in this distinctive application area of analytical toxicology are reviewed. The earlier state of the art of hair analysis was comprehensively covered by a dedicated book (Kintz, 2007a. Analytical and practical aspects of drug testing in hair. Boca Raton: CRC Press and Taylor & Francis, 382 p) that represents key reference of the present overview. Whereas the traditional organization of analytical methods in forensic toxicology divided target substances into quite homogeneous groups of drugs, with similar structures and chemical properties, the current approach often takes advantage of the rapid expansion of multiclass and multiresidue analytical procedures; the latter is made possible by the fast operation and extreme sensitivity of modern mass spectrometers. This change in the strategy of toxicological analysis is reflected in the presentation of the recent literature material, which is mostly based on a fit-for-purpose logic. Thus, general screening of unknown substances is applied in diverse forensic contexts than drugs of abuse testing, and different instrumentation (triple quadrupoles, time-of-flight analyzers, linear and orbital traps) is utilized to optimally cope with the scope. Other key issues of modern toxicology, such as cost reduction and high sample throughput, are discussed with reference to procedural and instrumental alternatives.

  9. A mass quadrupole spectrometry investigation on proton emission by nanosecond laser ablation

    SciTech Connect

    Caridi, F.

    2015-02-15

    A nanosecond pulsed Nd:YAG laser operating at the fundamental wavelength of 1064 nm and at an intensity of about 10{sup 10} W/cm{sup 2} was employed to irradiate hydrogenated polymers in vacuum. The produced plasma was characterized in terms of thermal and Coulomb interactions evaluating the equivalent temperature and the acceleration voltage developed in the non-equilibrium plasma core. Particles emission along the normal to the target surface was investigated by measuring, with the Hiden EQP 300 mass quadrupole spectrometer, ion energy distributions and fitting experimental data with the “Coulomb-Boltzmann-shifted” function. Time-of-flight technique was employed in order to measure the proton energy and yield. A comparison between experimental results is presented and discussed, with a special regard to the protons emission.

  10. International Mass Spectrometry Society (IMSS).

    PubMed

    Cooks, R G; Gelpi, E; Nibbering, N M

    2001-02-01

    This paper gives a brief description of the recently formalized International Mass Spectrometry Society (IMSS). It is presented here in order to increase awareness of the opportunities for collaboration in mass spectrometry in an international context. It also describes the recent 15th International Mass Spectrometry Conference, held August/September 2000, in Barcelona. Each of the authors is associated with the IMSS. The 15th Conference, which covers all of mass spectrometry on a triennial basis, was chaired by Professor Emilio Gelpi of the Instituto de Investigaciones Biomedicas, Barcelona. The outgoing and founding President of the IMSS is Professor Graham Cooks, Purdue University, and the incoming President is Professor Nico Nibbering, University of Amsterdam. Similar material has been provided to the Editors of other journals that cover mass spectrometry.

  11. A mass spectrometry primer for mass spectrometry imaging

    PubMed Central

    Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2011-01-01

    Mass spectrometry imaging (MSI), a rapidly growing subfield of chemical imaging, employs mass spectrometry (MS) technologies to create single- and multi-dimensional localization maps for a variety of atoms and molecules. Complimentary to other imaging approaches, MSI provides high chemical specificity and broad analyte coverage. This powerful analytical toolset is capable of measuring the distribution of many classes of inorganics, metabolites, proteins and pharmaceuticals in chemically and structurally complex biological specimens in vivo, in vitro, and in situ. The MSI approaches highlighted in this Methods in Molecular Biology volume provide flexibility of detection, characterization, and identification of multiple known and unknown analytes. The goal of this chapter is to introduce investigators who may be unfamiliar with MS to the basic principles of the mass spectrometric approaches as used in MSI. In addition to guidelines for choosing the most suitable MSI method for specific investigations, cross-references are provided to the chapters in this volume that describe the appropriate experimental protocols. PMID:20680583

  12. Compositional changes of human hair melanin resulting from bleach treatment investigated by nanoscale secondary ion mass spectrometry.

    PubMed

    Kojima, Toru; Yamada, Hiromi; Isobe, Mitsuru; Yamamoto, Toshihiko; Takeuchi, Miyuki; Aoki, Dan; Matsushita, Yasuyuki; Fukushima, Kazuhiko

    2014-11-01

    It is important to understand the influence of bleach treatment on human hair because it is one of the most important chemical treatments in hair cosmetic processes. A comparison of the elemental composition of melanin between virgin hair and bleached hair would provide important information about the structural changes of melanin. To investigate the elemental composition of melanin granules in virgin black hair and bleached hair, these hair cross-sections are analyzed by using a nanoscale secondary ion mass spectrometry (NanoSIMS). The virgin black hair and bleached hair samples were embedded in resin and smooth hair cross-sections were obtained using an ultramicrotome. NanoSIMS measurements were performed using a Cs(+) primary ion beam to detect negative secondary ions. More intensive (16) O(-) ions were detected from the melanin granules of bleached hair than from those of virgin black hair in NanoSIMS (16) O(-) ion image. In addition, it was indicated that (16) O(-) ion intensity and (16) O(-) /(12) C(14) N(-) ion intensity ratio of melanin granules in bleached hair were higher than those in virgin black hair. Nanoscale secondary ion mass spectrometry analysis of the cross-sections of virgin black hair and bleached hair indicated that the oxygen content in melanin granules was increased by bleach treatment. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Accelerator mass spectrometry.

    PubMed

    Hellborg, Ragnar; Skog, Göran

    2008-01-01

    In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg and even sub-mg size) and shorter measuring times (less than 1 hr). The equipment used for AMS is almost exclusively based on the electrostatic tandem accelerator, although some of the newest systems are based on a slightly different principle. Dedicated accelerators as well as older "nuclear physics machines" can be found in the 80 or so AMS laboratories in existence today. The most widely used isotope studied with AMS is 14C. Besides radiocarbon dating this isotope is used in climate studies, biomedicine applications and many other fields. More than 100,000 14C samples are measured per year. Other isotopes studied include 10Be, 26Al, 36Cl, 41Ca, 59Ni, 129I, U, and Pu. Although these measurements are important, the number of samples of these other isotopes measured each year is estimated to be less than 10% of the number of 14C samples. Copyright 2008 Wiley Periodicals, Inc.

  14. Quantitative mass spectrometry: an overview

    NASA Astrophysics Data System (ADS)

    Urban, Pawel L.

    2016-10-01

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry-especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements. This article is part of the themed issue 'Quantitative mass spectrometry'.

  15. Flow-Tube Investigations of Hypergolic Reactions of a Dicyanamide Ionic Liquid Via Tunable Vacuum Ultraviolet Aerosol Mass Spectrometry.

    PubMed

    Chambreau, Steven D; Koh, Christine J; Popolan-Vaida, Denisia M; Gallegos, Christopher J; Hooper, Justin B; Bedrov, Dmitry; Vaghjiani, Ghanshyam L; Leone, Stephen R

    2016-10-07

    The unusually high heats of vaporization of room-temperature ionic liquids (RTILs) complicate the utilization of thermal evaporation to study ionic liquid reactivity. Although effusion of RTILs into a reaction flow-tube or mass spectrometer is possible, competition between vaporization and thermal decomposition of the RTIL can greatly increase the complexity of the observed reaction products. In order to investigate the reaction kinetics of a hypergolic RTIL, 1-butyl-3-methylimidazolium dicyanamide (BMIM(+)DCA(-)) was aerosolized and reacted with gaseous nitric acid, and the products were monitored via tunable vacuum ultraviolet photoionization time-of-flight mass spectrometry at the Chemical Dynamics Beamline 9.0.2 at the Advanced Light Source. Reaction product formation at m/z 42, 43, 44, 67, 85, 126, and higher masses was observed as a function of HNO3 exposure. The identities of the product species were assigned to the masses on the basis of their ionization energies. The observed exposure profile of the m/z 67 signal suggests that the excess gaseous HNO3 initiates rapid reactions near the surface of the RTIL aerosol. Nonreactive molecular dynamics simulations support this observation, suggesting that diffusion within the particle may be a limiting step. The mechanism is consistent with previous reports that nitric acid forms protonated dicyanamide species in the first step of the reaction.

  16. Mass spectrometry in environmental toxicology.

    PubMed

    Groh, Ksenia J; Suter, Marc J-F

    2014-01-01

    In environmental toxicology, mass spectrometry can be applied to evaluate both exposure to chemicals as well as their effects in organisms. Various ultra-trace techniques are employed today to measure pollutants in different environmental compartments. Increasingly, effect-directed analysis is being applied to focus chemical monitoring on sites of ecotoxicological concern. Mass spectrometry is also very instrumental for studying the interactions of chemicals with organisms on the molecular and cellular level, providing new insights into mechanisms of toxicity. In the future, diverse mass spectrometry-based techniques are expected to become even more widely used in this field, contributing to the refinement of currently used environmental risk assessment strategies.

  17. Ion mobility-mass spectrometry.

    PubMed

    Kanu, Abu B; Dwivedi, Prabha; Tam, Maggie; Matz, Laura; Hill, Herbert H

    2008-01-01

    This review article compares and contrasts various types of ion mobility-mass spectrometers available today and describes their advantages for application to a wide range of analytes. Ion mobility spectrometry (IMS), when coupled with mass spectrometry, offers value-added data not possible from mass spectra alone. Separation of isomers, isobars, and conformers; reduction of chemical noise; and measurement of ion size are possible with the addition of ion mobility cells to mass spectrometers. In addition, structurally similar ions and ions of the same charge state can be separated into families of ions which appear along a unique mass-mobility correlation line. This review describes the four methods of ion mobility separation currently used with mass spectrometry. They are (1) drift-time ion mobility spectrometry (DTIMS), (2) aspiration ion mobility spectrometry (AIMS), (3) differential-mobility spectrometry (DMS) which is also called field-asymmetric waveform ion mobility spectrometry (FAIMS) and (4) traveling-wave ion mobility spectrometry (TWIMS). DTIMS provides the highest IMS resolving power and is the only IMS method which can directly measure collision cross-sections. AIMS is a low resolution mobility separation method but can monitor ions in a continuous manner. DMS and FAIMS offer continuous-ion monitoring capability as well as orthogonal ion mobility separation in which high-separation selectivity can be achieved. TWIMS is a novel method of IMS with a low resolving power but has good sensitivity and is well intergrated into a commercial mass spectrometer. One hundred and sixty references on ion mobility-mass spectrometry (IMMS) are provided.

  18. Investigations into the origins of polyatomic ions in inductively coupled plasma-mass spectrometry

    SciTech Connect

    McIntyre, Sally M.

    2010-01-01

    An inductively coupled plasma-mass spectrometer (ICP-MS) is an elemental analytical instrument capable of determining nearly all elements in the periodic table at limits of detection in the parts per quadrillion and with a linear analytical range over 8-10 orders of magnitude. Three concentric quartz tubes make up the plasma torch. Argon gas is spiraled through the outer tube and generates the plasma powered by a looped load coil operating at 27.1 or 40.6 MHz. The argon flow of the middle channel is used to keep the plasma above the innermost tube through which solid or aqueous sample is carried in a third argon stream. A sample is progressively desolvated, atomized and ionized. The torch is operated at atmospheric pressure. To reach the reduced pressures of mass spectrometers, ions are extracted through a series of two, approximately one millimeter wide, circular apertures set in water cooled metal cones. The space between the cones is evacuated to approximately one torr. The space behind the second cone is pumped down to, or near to, the pressure needed for the mass spectrometer (MS). The first cone, called the sampler, is placed directly in the plasma plume and its position is adjusted to the point where atomic ions are most abundant. The hot plasma gas expands through the sampler orifice and in this expansion is placed the second cone, called the skimmer. After the skimmer traditional MS designs are employed, i.e. quadrupoles, magnetic sectors, time-of-flight. ICP-MS is the leading trace element analysis technique. One of its weaknesses are polyatomic ions. This dissertation has added to the fundamental understanding of some of these polyatomic ions, their origins and behavior. Although mainly continuing the work of others, certain novel approaches have been introduced here. Chapter 2 includes the first reported efforts to include high temperature corrections to the partition functions of the polyatomic ions in ICP-MS. This and other objections to preceeding

  19. Investigating the effect of mixing ratio on molar mass distributions of synthetic polymers determined by MALDI-TOF mass spectrometry using design of experiments.

    PubMed

    Brandt, Heike; Ehmann, Thomas; Otto, Matthias

    2010-11-01

    It is well known that the mixing ratio affects the molar mass distribution of synthetic polymers determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Surely, the molar mixing ratio determines whether a mass spectrum will be obtained or not. However, depending on the mass range, several effects such as multimer formation occur, which might be a source of errors in molar mass distribution calculations. In this study, the effect of mixing ratio was investigated for several synthetic polymers, including polystyrene (PS), poly(dimethylsiloxane) (PDMS), poly(ethylene glycol) (PEG), and poly(methyl methacrylate) (PMMA) using statistical designs of experiments. The 2(3) full factorial design was found to be suitable in the study of more than 1000 samples. The obtained MALDI mass spectra as well as the ANOVA statistics show that the mixing ratio affects the molar mass distribution. The optimal mixing ratio for a defined synthetic polymer depends on the studied combination (matrix, cationization reagent, solvent).

  20. Direct Analysis in Real Time Mass Spectrometry for the Nondestructive Investigation of Conservation Treatments of Cultural Heritage

    PubMed Central

    Bearman, Greg; France, Fenella; Barberis, Elettra; Shor, Pnina; Marengo, Emilio

    2016-01-01

    Today the long-term conservation of cultural heritage is a big challenge: often the artworks were subjected to unknown interventions, which eventually were found to be harmful. The noninvasive investigation of the conservation treatments to which they were subjected to is a crucial step in order to undertake the best conservation strategies. We describe here the preliminary results on a quick and direct method for the nondestructive identification of the various interventions of parchment by means of direct analysis in real time (DART) ionization and high-resolution time-of-flight mass spectrometry and chemometrics. The method has been developed for the noninvasive analysis of the Dead Sea Scrolls, one of the most important archaeological discoveries of the 20th century. In this study castor oil and glycerol parchment treatments, prepared on new parchment specimens, were investigated in order to evaluate two different types of operations. The method was able to identify both treatments. In order to investigate the effect of the ion source temperature on the mass spectra, the DART-MS analysis was also carried out at several temperatures. Due to the high sensitivity, simplicity, and no sample preparation requirement, the proposed analytical methodology could help conservators in the challenging analysis of unknown treatments in cultural heritage. PMID:27957383

  1. Direct Analysis in Real Time Mass Spectrometry for the Nondestructive Investigation of Conservation Treatments of Cultural Heritage.

    PubMed

    Manfredi, Marcello; Robotti, Elisa; Bearman, Greg; France, Fenella; Barberis, Elettra; Shor, Pnina; Marengo, Emilio

    2016-01-01

    Today the long-term conservation of cultural heritage is a big challenge: often the artworks were subjected to unknown interventions, which eventually were found to be harmful. The noninvasive investigation of the conservation treatments to which they were subjected to is a crucial step in order to undertake the best conservation strategies. We describe here the preliminary results on a quick and direct method for the nondestructive identification of the various interventions of parchment by means of direct analysis in real time (DART) ionization and high-resolution time-of-flight mass spectrometry and chemometrics. The method has been developed for the noninvasive analysis of the Dead Sea Scrolls, one of the most important archaeological discoveries of the 20th century. In this study castor oil and glycerol parchment treatments, prepared on new parchment specimens, were investigated in order to evaluate two different types of operations. The method was able to identify both treatments. In order to investigate the effect of the ion source temperature on the mass spectra, the DART-MS analysis was also carried out at several temperatures. Due to the high sensitivity, simplicity, and no sample preparation requirement, the proposed analytical methodology could help conservators in the challenging analysis of unknown treatments in cultural heritage.

  2. Investigation of combwax of honeybees with high-temperature gas chromatography and high-temperature gas chromatography-chemical ionization mass spectrometry. II: High-temperature gas chromatography-chemical ionization mass spectrometry.

    PubMed

    Aichholz, R; Lorbeer, E

    2000-06-23

    Crude combwax of six various honey bee species have been analyzed by high-temperature gas chromatography (HTGC)-chemical ionization mass spectrometry after a two-step silylation procedure. An optimized chromatographic procedure, described previously, enables the separation of high-molecular mass lipid compounds resulting in a characteristic fingerprint of the combwaxes of different honeybee species. The coupling of HTGC to mass spectrometry requires appropriate instrumentation in order to achieve sufficient sensitivity at high elution temperatures and avoid loss of chromatographic resolution. Chemical ionization was carried out using methane as reagent gas in order to determine the molecular mass of the individual compounds by means of abundant quasi molecular ions. To confirm the presence of unsaturated wax esters, ammonia was used as reagent gas. More than 80 lipid constituents were separated and characterized by their mass spectra. Representative chemical ionization mass spectra of individual compounds are presented. Both, HTGC-flame ionization detection data and the results of the HTGC-mass spectrometric investigations enabled a rapid profiling of the individual classes of compounds in crude combwaxes.

  3. Investigation of the ligand spectrum of human sterol carrier protein 2 using a direct mass spectrometry assay.

    PubMed

    Stanley, Will A; Versluis, Kees; Schultz, Carsten; Heck, Albert J R; Wilmanns, Matthias

    2007-05-01

    Sterol carrier protein 2 (SCP2) has been investigated by nearly native electrospray ionisation mass spectrometry in the presence of long chain fatty acyl CoAs (LCFA-CoAs) and carnitine derivatives of equivalent fatty acid chain length (LCFA-carnitines). Four SCP2 constructs were compared to examine the influence of the N-terminal presequence and the C-terminal peroxisomal targeting signal on ligand binding. Removal of N- or C-terminal residues did not influence ligand binding. The observation that LCFA-CoAs are high affinity ligands for SCP2 was confirmed, while LCFA-carnitines were demonstrated for the first time not to interact with SCP2. LCFA-CoAs formed non-covalent complexes with SCP2 of 2:1 and 1:1 stoichiometry, which could be dissociated by elevating the energy of the ions upon entrance to the mass spectrometer. A fluorescence-competition assay using Nile Red butyric acid confirmed the mass spectrometric observations in solution. The physiological significance of the lack of LCFA-carnitine binding by SCP2 is discussed.

  4. Review: mass spectrometry in Russia.

    PubMed

    Zaikin, Vladimir G; Sysoev, Alexander A

    2013-01-01

    The present review covers the main research in the area of mass spectrometry from the 1990s which was about the same time as the Russian Federation emerged from the collapse of the Soviet Union (USSR). It consists of two main parts-application of mass spectrometry to chemistry and related fields and creation and development of mass spectrometric technique. Both traditional and comparatively new mass spectrometric methods were used to solve various problems in organic chemistry (reactivity of gas-phase ions, structure elucidation and problems of identification, quantitative and trace analysis, differentiation of stereoisomers, derivatization approaches etc.), biochemistry (proteomics and peptidomics, lipidomics), medical chemistry (mainly the search of biomarkers, pharmacology, doping control), environmental, petrochemistry, polymer chemistry, inorganic and physical chemistry, determination of natural isotope ratio etc. Although a lot of talented mass spectrometrists left Russia and moved abroad after the collapse of the Soviet Union, the vitality of the mass spectral community proved to be rather high, which allowed the continuation of new developments in the field of mass spectrometric instrumentation. They are devoted to improvements in traditional magnetic sector mass spectrometers and the development of new ion source types, to analysis and modification of quadrupole, time-of-flight (ToF) and ion cyclotron resonance (ICR) analyzers. The most important achievements are due to the creation of multi-reflecting ToF mass analyzers. Special attention was paid to the construction of compact mass spectrometers, particularly for space exploration, of combined instruments, such as ion mobility spectrometer/mass spectrometer and accelerating mass spectrometers. The comparatively young Russian Mass Spectrometry Society is working hard to consolidate the mass spectrometrists from Russia and foreign countries, to train young professionals on new appliances and regularly

  5. Linear electric field mass spectrometry

    DOEpatents

    McComas, David J.; Nordholt, Jane E.

    1992-01-01

    A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.

  6. Linear electric field mass spectrometry

    DOEpatents

    McComas, D.J.; Nordholt, J.E.

    1992-12-01

    A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

  7. Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging.

    PubMed

    Kiss, András; Smith, Donald F; Jungmann, Julia H; Heeren, Ron M A

    2013-12-30

    Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyatomic primary ion sources, are required to exploit the full potential of microscope mode mass spectrometry imaging, i.e. to efficiently push the limits of ultra-high spatial resolution, sample throughput and sensitivity. In this work, a C60 primary source was combined with a commercial mass microscope for microscope mode secondary ion mass spectrometry imaging. The detector setup is a pixelated detector from the Medipix/Timepix family with high-voltage post-acceleration capabilities. The system's mass spectral and imaging performance is tested with various benchmark samples and thin tissue sections. The high secondary ion yield (with respect to 'traditional' monatomic primary ion sources) of the C60 primary ion source and the increased sensitivity of the high voltage detector setup improve microscope mode secondary ion mass spectrometry imaging. The analysis time and the signal-to-noise ratio are improved compared with other microscope mode imaging systems, all at high spatial resolution. We have demonstrated the unique capabilities of a C60 ion microscope with a Timepix detector for high spatial resolution microscope mode secondary ion mass spectrometry imaging. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Investigating the Origin and Evolution of Venus with In Situ Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Trainer, M. G.; Mahaffy, P. R.; Brinckerhoff, W. B.; Johnson, N. M.; Glaze, L. S.

    2015-01-01

    Measurement of noble gas abundances on Venus remain a high priority for planetary science. These studies are only possible through in situ measurement, and can be accomplished by a modern neutral mass spectrometer (NMS) such as that developed at NASA Goddard, based on flight-proven technology. Here we show how the measurement of noble gases can be secured using demonstrated enrichment techniques.

  9. Mass spectrometry investigations on electrolyte degradation products for the development of nanocomposite electrodes in lithium ion batteries.

    PubMed

    Gireaud, Laurent; Grugeon, Sylvie; Pilard, Serge; Guenot, Pierre; Tarascon, Jean-Marie; Laruelle, Stephane

    2006-06-01

    In the continuing challenge to find new routes to improve the performance of commercial lithium ion batteries cycling in alkyl carbonate-based electrolyte solutions, original designs, and new electrode materials are under active worldwide investigation. Our group has focused on the electrochemical behavior of a new generation of nanocomposite electrodes showing improved capacities (up to 3 times the capacity of conventional electrode materials). However, moving down to "nanometric-scale" active materials leads to a significant increase in electrolyte degradation, compared to that taking place within commercial batteries. Postmortem electrolyte studies on experimental coin cells were conducted to understand the degradation mechanisms. Structural analysis of the organic degradation products were investigated using a combination of complementary high-resolution mass spectrometry techniques: desorption under electron impact, electrospray ionization, and gas chromatography coupled to a mass spectrometer equipped with electron impact and chemical ionization ion sources. Numerous organic degradation products such as ethylene oxide oligomers (with methyl, hydroxyl, phosphate, and methyl carbonate endings) have been characterized. In light of our findings, possible chemical or electrochemical pathways are proposed to account for their formation. A thorough knowledge of these degradation mechanisms will enable us to propose new electrolyte formulations to optimize nanocomposite-based lithium ion battery performance.

  10. Investigating the Interaction between the Neonatal Fc Receptor and Monoclonal Antibody Variants by Hydrogen/Deuterium Exchange Mass Spectrometry*

    PubMed Central

    Jensen, Pernille Foged; Larraillet, Vincent; Schlothauer, Tilman; Kettenberger, Hubert; Hilger, Maximiliane; Rand, Kasper D.

    2015-01-01

    The recycling of immunoglobulins by the neonatal Fc receptor (FcRn) is of crucial importance in the maintenance of antibody levels in plasma and is responsible for the long half-lives of endogenous and recombinant monoclonal antibodies. From a therapeutic point of view there is great interest in understanding and modulating the IgG–FcRn interaction to optimize antibody pharmacokinetics and ultimately improve efficacy and safety. Here we studied the interaction between a full-length human IgG1 and human FcRn via hydrogen/deuterium exchange mass spectrometry and targeted electron transfer dissociation to map sites perturbed by binding on both partners of the IgG–FcRn complex. Several regions in the antibody Fc region and the FcRn were protected from exchange upon complex formation, in good agreement with previous crystallographic studies of FcRn in complex with the Fc fragment. Interestingly, we found that several regions in the IgG Fab region also showed reduced deuterium uptake. Our findings indicate the presence of hitherto unknown FcRn interaction sites in the Fab region or a possible conformational link between the IgG Fc and Fab regions upon FcRn binding. Further, we investigated the role of IgG glycosylation in the conformational response of the IgG–FcRn interaction. Removal of antibody glycans increased the flexibility of the FcRn binding site in the Fc region. Consequently, FcRn binding did not induce a similar conformational stabilization of deglycosylated IgG as observed for the wild-type glycosylated IgG. Our results provide new molecular insight into the IgG–FcRn interaction and illustrate the capability of hydrogen/deuterium exchange mass spectrometry to advance structural proteomics by providing detailed information on the conformation and dynamics of large protein complexes in solution. PMID:25378534

  11. Investigating the interaction between the neonatal Fc receptor and monoclonal antibody variants by hydrogen/deuterium exchange mass spectrometry.

    PubMed

    Jensen, Pernille Foged; Larraillet, Vincent; Schlothauer, Tilman; Kettenberger, Hubert; Hilger, Maximiliane; Rand, Kasper D

    2015-01-01

    The recycling of immunoglobulins by the neonatal Fc receptor (FcRn) is of crucial importance in the maintenance of antibody levels in plasma and is responsible for the long half-lives of endogenous and recombinant monoclonal antibodies. From a therapeutic point of view there is great interest in understanding and modulating the IgG-FcRn interaction to optimize antibody pharmacokinetics and ultimately improve efficacy and safety. Here we studied the interaction between a full-length human IgG(1) and human FcRn via hydrogen/deuterium exchange mass spectrometry and targeted electron transfer dissociation to map sites perturbed by binding on both partners of the IgG-FcRn complex. Several regions in the antibody Fc region and the FcRn were protected from exchange upon complex formation, in good agreement with previous crystallographic studies of FcRn in complex with the Fc fragment. Interestingly, we found that several regions in the IgG Fab region also showed reduced deuterium uptake. Our findings indicate the presence of hitherto unknown FcRn interaction sites in the Fab region or a possible conformational link between the IgG Fc and Fab regions upon FcRn binding. Further, we investigated the role of IgG glycosylation in the conformational response of the IgG-FcRn interaction. Removal of antibody glycans increased the flexibility of the FcRn binding site in the Fc region. Consequently, FcRn binding did not induce a similar conformational stabilization of deglycosylated IgG as observed for the wild-type glycosylated IgG. Our results provide new molecular insight into the IgG-FcRn interaction and illustrate the capability of hydrogen/deuterium exchange mass spectrometry to advance structural proteomics by providing detailed information on the conformation and dynamics of large protein complexes in solution. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Investigating the Origin and Evolution of Venus with In Situ Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Trainer, M. G.; Mahaffy, P. R.; Brinckerhoff, W. B.; Johnson, N. M.; Glaze, L. S.

    2015-10-01

    Measurement of noble gas abundances on Venus remain a high priority for planetary science [1,2]. These studies are only possible through in situ measurement, and can be accomplished by a modern neutral mass spectrometer (NMS) such as that developed at NASA Goddard, based on flight-proven technology. Here we show how the measurement of noble gases can be secured using demonstrated enrichment techniques.

  13. Investigating types and sources of organic aerosol in Rocky Mountain National Park using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L., Jr.

    2015-01-01

    The environmental impacts of atmospheric particles are highlighted in remote areas where visibility and ecosystem health can be degraded by even relatively low particle concentrations. Submicron particle size, composition, and source apportionment were explored at Rocky Mountain National Park using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer. This summer campaign found low average, but variable, particulate mass (PM) concentrations (max = 93.1 μg m-3, avg. = 5.13 ± 2.72 μg m-3) of which 75.2 ± 11.1% is organic. Low-volatility oxidized organic aerosol (LV-OOA, 39.3% of PM1 on average) identified using Positive Matrix Factorization appears to be mixed with ammonium sulfate (3.9% and 16.6% of mass, respectively), while semi-volatile OOA (27.6%) is correlated with ammonium nitrate (nitrate: 4.3%); concentrations of these mixtures are enhanced with upslope (SE) surface winds from the densely populated Front Range area, indicating the importance of transport. A local biomass burning organic aerosol (BBOA, 8.4%) source is suggested by mass spectral cellulose combustion markers (m/z 60 and 73) limited to brief, high-concentration, polydisperse events (suggesting fresh combustion), a diurnal maximum at 22:00 local standard time when campfires were set at adjacent summer camps, and association with surface winds consistent with local campfire locations. The particle characteristics determined here represent typical summertime conditions at the Rocky Mountain site based on comparison to ~10 years of meteorological, particle composition, and fire data.

  14. Investigating types and sources of organic aerosol in Rocky Mountain National Park using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L., Jr.

    2014-07-01

    The environmental impacts of atmospheric particles are highlighted in remote areas where visibility and ecosystem health can be degraded by even relatively low particle concentrations. Submicron particle size, composition, and source apportionment were explored at Rocky Mountain National Park using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer. This summer campaign found low average, but variable, particulate mass (PM) concentrations (max = 93.1 μg m-3, avg. = 5.13 ± 2.72 μg m-3) of which 75.2 ± 11.1% is organic. Low-volatility oxidized organic aerosol (LV-OOA, 39.3% of PM1 on average) identified using Positive Matrix Factorization appears to be mixed with ammonium sulfate (3.9 and 16.6% of mass, respectively), while semi-volatile OOA (27.6%) is correlated with ammonium nitrate (nitrate: 4.3%); concentrations of these mixtures are enhanced with upslope (SE) surface winds from the densely populated Front Range area, indicating the importance of transport. A local biomass burning organic aerosol (BBOA, 8.4%) source is suggested by mass spectral cellulose combustion markers (m/zs 60 and 73) limited to brief, high-concentration, polydisperse events (suggesting fresh combustion), a diurnal maximum at 22:00 local standard time (LST) when campfires were set at adjacent summer camps, and association with surface winds consistent with local campfire locations. The particle characteristics determined here represent typical summertime conditions at the Rocky Mountain site based on comparison to ∼10 years of meteorological, particle composition, and fire data.

  15. Structural Investigation of Fluoridated POSS Cages Using Ion Mobility Mass Spectrometry and Molecular Mechanics (Preprint)

    DTIC Science & Technology

    2008-01-09

    organic polymer. For example, the low surface energy properties of fluorinated POSS compounds have been used to augment both fluorinated and non... fluorinated polymers.10-13 Many POSS monomers have been successfully characterized using MALDI techniques14-16 in conjunction with ion mobility mass...nucleophilic attack, are shown in blue. Negative contours, showing susceptibility to electrophilic attack, are shown in red. The positive contour of

  16. Structure investigation of codeine drug using mass spectrometry, thermal analyses and semi-emperical molecular orbital (MO) calculations

    NASA Astrophysics Data System (ADS)

    Zayed, M. A.; Hawash, M. F.; Fahmey, M. A.

    2006-05-01

    Codeine is an analgesic with uses similar to morphine, but it has a mild sedative effect. It is preferable used as phosphate form and it is often administrated by mouth with aspirin or paracetamol. Therefore, it is important to investigate its structure to know the active groups and weak bonds responsible for its medical activity. Consequently in the present work, codeine was investigated by mass spectrometry and thermal analyses (TG, DTG and DTA) and confirming by semi-empirical MO-calculation (PM3 method) in the neutral and positively charged forms of the drug. Some results of studying the d-block element complexes of codeine were used to declare the relationship between drug structure and its chemical reactivity in vitro system. The mass spectra and thermal analyses fragmentation pathways were proposed and compared to each other to select the most suitable scheme representing the correct fragmentation of this drug. From EI mass spectra, the main primary cleavage site of the charged drug molecule is that due to β-cleavage to nitrogen atom in its skeleton. It occurs in two parallel mechanisms with the same possibility, i.e. no difference in appearance activation energy between them. In the neutral drug form the primary site cleavage is that occurs in the ether ring. Thermal analyses of the neutral form of the drug revealed the high response of the drug to the temperature variation with very fast rate. It decomposed in several sequential steps in the temperature range 200-600 °C. The initial thermal fragments are very similar to that obtained by mass spectrometric fragmentation. Therefore, comparison between mass and thermal helps in selection of the proper pathway representing the fragmentation of this drug. This comparison successfully confirmed by MOC. These calculations give the bond order, charge distribution, heat of formation and possible hybridization of some atoms in different position of the drug skeleton. This helps the successful choice of the weakest

  17. Structure investigation of codeine drug using mass spectrometry, thermal analyses and semi-emperical molecular orbital (MO) calculations.

    PubMed

    Zayed, M A; Hawash, M F; Fahmey, M A

    2006-05-15

    Codeine is an analgesic with uses similar to morphine, but it has a mild sedative effect. It is preferable used as phosphate form and it is often administrated by mouth with aspirin or paracetamol. Therefore, it is important to investigate its structure to know the active groups and weak bonds responsible for its medical activity. Consequently in the present work, codeine was investigated by mass spectrometry and thermal analyses (TG, DTG and DTA) and confirming by semi-empirical MO-calculation (PM3 method) in the neutral and positively charged forms of the drug. Some results of studying the d-block element complexes of codeine were used to declare the relationship between drug structure and its chemical reactivity in vitro system. The mass spectra and thermal analyses fragmentation pathways were proposed and compared to each other to select the most suitable scheme representing the correct fragmentation of this drug. From EI mass spectra, the main primary cleavage site of the charged drug molecule is that due to beta-cleavage to nitrogen atom in its skeleton. It occurs in two parallel mechanisms with the same possibility, i.e. no difference in appearance activation energy between them. In the neutral drug form the primary site cleavage is that occurs in the ether ring. Thermal analyses of the neutral form of the drug revealed the high response of the drug to the temperature variation with very fast rate. It decomposed in several sequential steps in the temperature range 200-600 degrees C. The initial thermal fragments are very similar to that obtained by mass spectrometric fragmentation. Therefore, comparison between mass and thermal helps in selection of the proper pathway representing the fragmentation of this drug. This comparison successfully confirmed by MOC. These calculations give the bond order, charge distribution, heat of formation and possible hybridization of some atoms in different position of the drug skeleton. This helps the successful choice of the

  18. Mass spectrometry. [in organic chemistry

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

    1978-01-01

    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  19. Mass spectrometry. [in organic chemistry

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

    1978-01-01

    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  20. Large-Scale Mass Spectrometry Imaging Investigation of Consequences of Cortical Spreading Depression in a Transgenic Mouse Model of Migraine

    NASA Astrophysics Data System (ADS)

    Carreira, Ricardo J.; Shyti, Reinald; Balluff, Benjamin; Abdelmoula, Walid M.; van Heiningen, Sandra H.; van Zeijl, Rene J.; Dijkstra, Jouke; Ferrari, Michel D.; Tolner, Else A.; McDonnell, Liam A.; van den Maagdenberg, Arn M. J. M.

    2015-06-01

    Cortical spreading depression (CSD) is the electrophysiological correlate of migraine aura. Transgenic mice carrying the R192Q missense mutation in the Cacna1a gene, which in patients causes familial hemiplegic migraine type 1 (FHM1), exhibit increased propensity to CSD. Herein, mass spectrometry imaging (MSI) was applied for the first time to an animal cohort of transgenic and wild type mice to study the biomolecular changes following CSD in the brain. Ninety-six coronal brain sections from 32 mice were analyzed by MALDI-MSI. All MSI datasets were registered to the Allen Brain Atlas reference atlas of the mouse brain so that the molecular signatures of distinct brain regions could be compared. A number of metabolites and peptides showed substantial changes in the brain associated with CSD. Among those, different mass spectral features showed significant ( t-test, P < 0.05) changes in the cortex, 146 and 377 Da, and in the thalamus, 1820 and 1834 Da, of the CSD-affected hemisphere of FHM1 R192Q mice. Our findings reveal CSD- and genotype-specific molecular changes in the brain of FHM1 transgenic mice that may further our understanding about the role of CSD in migraine pathophysiology. The results also demonstrate the utility of aligning MSI datasets to a common reference atlas for large-scale MSI investigations.

  1. Investigations on the direct introduction of cigarette smoke for trace elements analysis by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Chang, Michael J.; Naworal, John D.; Walker, Kathleen; Connell, Chris T.

    2003-11-01

    Direct introduction of mainstream cigarette smoke into an inductively coupled plasma mass spectrometry (ICP-MS) has been investigated with respect to its feasibility for on-line analysis of trace elements. An automated apparatus was designed and built interfacing a smoking machine with an ICP-MS for smoke generation, collection, injection and analysis. Major and minor elements present in the particulate phase and the gas phase of mainstream cigarette smoke of 2R4F reference cigarettes have been qualitatively identified by examination of their full mass spectra. This method provides a rapid-screening analysis of the transfer of trace elements into mainstream smoke during cigarette combustion. A full suite of elements present in the whole cigarette smoke has been identified, including As, B, Ba, Br, Cd, Cl, Cs, Cu, Hg, I, K, Li, Mn, Na, Pb, Rb, Sb, Sn, Tl and Zn. Of these elements, the major portions of B, Ba, Cs, Cu, K, Li, Mn, Na, Pb, Rb, Sn, Tl and Zn are present in the particulate phase, whereas the major portion of Hg is present in the gas phase. As, Br, Cd, Cl, I and Sb exist in a distribution between the gas phase and the particulate phase. Depending on the element, the precision of measurement ranges from 5 to 25% in terms of relative standard deviation of peak height and peak area, based on the fourth puff of 2R4F mainstream cigarette smoke analyzed in five smoking replicates.

  2. Hydrodynamic chromatography coupled with single particle-inductively coupled plasma mass spectrometry for investigating nanoparticles agglomerates.

    PubMed

    Rakcheev, Denis; Philippe, Allan; Schaumann, Gabriele E

    2013-11-19

    Studying the environmental fate of engineered or natural colloids requires efficient methods for measuring their size and quantifying them in the environment. For example, an ideal method should maintain its correctness, accuracy, reproducibility, and robustness when applied to samples contained in complex matrixes and distinguish the target particles from the natural colloidal background signals. Since it is expected that a large portion of nanoparticles will form homo- or heteroagglomerates when released into environmental media, it is necessary to differentiate agglomerates from primary particles. At present, most sizing techniques do not fulfill these requirements. In this study, we used online coupling of two promising complementary sizing techniques: hydrodynamic chromatography (HDC) and single-particle ICPMS analysis to analyze gold nanoparticles agglomerated under controlled conditions. We used the single-particle mode of the ICPMS detector to detect single particles eluted from an HDC-column and determine a mass and an effective diameter for each particle using a double calibration approach. The average agglomerate relative density and fractal dimension were calculated using these data and used to follow the morphological evolution of agglomerates over time during the agglomeration process. The results demonstrate the ability of HDC coupled to single-particle analysis to identify and characterize nanoparticle homoagglomerates and is a very promising technique for the analysis of colloids in complex media.

  3. Instrumentation for mass spectrometry: 1997

    SciTech Connect

    McLuckey, S.A.

    1997-08-01

    All mass spectrometry experiments involve the manipulation of material, an interface with the mass spectrometer, ionization, ion manipulation/analysis, detection and data collection/reduction. Each of these elements involve instrumentation. The wide range of species now amenable to mass spectrometry and the diverse areas of physical science in which it plays a role have led to a seemingly unlimited array of instrumental combinations. However, only a limited number of mass analyzers, and their combinations, dominate. The dominant analyzers include time-of-flight, Fourier transform ion cyclotron resonance, the Paul trap, the mass filter, and the sector mass spectrometer. Why there are so few (or so many, depending upon one`s point of view) can be understood upon consideration of a set of mass analyzer figures of merit. These include mass resolution, mass accuracy, mass range, dynamic range, abundance sensitivity, precision, efficiency, speed, MS{sup n} capability, compatibility with the ionizer, cost, and size. The most appropriate form of mass spectrometry is determined by the priorities of the particular measurement placed on the various mass analyzer characteristics and the relative strengths of the analyzers in meeting the requirements. Each of the analyzer types has a unique set of figures of merit that makes it optimally suited for particular applications. This paper discusses these figures of merit, provides data illustrating recent developments for each analyzer type, and gives the figures of merit of each type of analyzer as they stand in 1997. 101 refs., 24 figs.

  4. Mass spectrometry guided structural biology.

    PubMed

    Liko, Idlir; Allison, Timothy M; Hopper, Jonathan Ts; Robinson, Carol V

    2016-10-01

    With the convergence of breakthroughs in structural biology, specifically breaking the resolution barriers in cryo-electron microscopy and with continuing developments in crystallography, novel interfaces with other biophysical methods are emerging. Here we consider how mass spectrometry can inform these techniques by providing unambiguous definition of subunit stoichiometry. Moreover recent developments that increase mass spectral resolution enable molecular details to be ascribed to unassigned density within high-resolution maps of membrane and soluble protein complexes. Importantly we also show how developments in mass spectrometry can define optimal solution conditions to guide downstream structure determination, particularly of challenging biomolecules that refuse to crystallise.

  5. Quantitative mass spectrometry: an overview

    PubMed Central

    2016-01-01

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry—especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644965

  6. Investigation on the enantioseparation of duloxetine by capillary electrophoresis, NMR, and mass spectrometry.

    PubMed

    Sánchez-López, Elena; Salgado, Antonio; Crego, Antonio L; Marina, María Luisa

    2014-10-01

    The enantiomeric separation of the antidepressant drug duloxetine was investigated by CE using 15 neutral CDs as chiral selectors. Among them, (2-hydroxypropyl)-β-CD and methyl-γ-CD gave rise to the highest enantioresolution. The enantiomer migration order for duloxetine was found to be reversed depending on the CD employed: R-duloxetine was the first-migrating enantiomer for (2-hydroxypropyl)-β-CD while it was the second-migrating enantiomer for methyl-γ-CD. NMR and MS experiments were performed in order to justify this behavior. Although the elucidation of the structure of the enantiomer-CD complexes was not possible, their averaged stoichiometry was studied and their apparent and averaged equilibrium constants were calculated. The results obtained showed that the chiral separation of duloxetine by CE depends not only on the thermodynamic stability of the enantiomer-chiral selector complexes but also on their electrophoretic mobility.

  7. Investigating the structural transitions of proteins during dissolution by mass spectrometry.

    PubMed

    Gong, Xiaoyun; Xiong, Xingchuang; Qi, Lin; Fang, Xiang

    2017-03-01

    An appropriate solvent environment is essential for the implementation of biological functions of proteins. Interactions between protein residues and solvent molecules are of great importance for proteins to maintain their active structure and catalyze biochemical reactions. In this study, we investigated such interactions and studied the structural transitions of proteins during their dissolution process. Our previously developed technique, namely solvent assisted electric field induced desorption/ionization, was used for the dissolution and immediate ionization of proteins. Different solvents and proteins were involved in the investigation. According to the results, cytochrome c underwent significant unfolding during dissolution in the most commonly used NH4Ac buffer. The unfolding got more serious when the concentration of NH4Ac was further increased. Extending the dissolution time resulted in the re-folding of cytochrome c. In comparison, no unfolding was observed if cytochrome c was pre-dissolved in NH4Ac buffer and detected by nano-ESI. Furthermore, no unfolding was observed during the dissolution process of cytochrome c in water. Interactions between the residues of cytochrome c and the solute of NH4Ac might be the reason for the unfolding phenomenon. Similar unfolding phenomenon was observed on holo-myoglobin. However, the observed dissolution feature of insulin was different. No unfolding was observed on insulin during dissolution in NH4Ac buffers. Insulin underwent observable unfolding when water was used for dissolution. This might be due to the structural difference between different proteins. The obtained results in the present study furthered our insights into the interactions between proteins and the solvents during the phase transition of dissolution.

  8. Phenolic compounds from Bursera simaruba Sarg. bark: phytochemical investigation and quantitative analysis by tandem mass spectrometry.

    PubMed

    Maldini, Mariateresa; Montoro, Paola; Piacente, Sonia; Pizza, Cosimo

    2009-03-01

    Phytochemical investigation of the methanolic extract of Bursera simaruba bark led to the isolation of 11 compounds, including lignans yatein, beta-peltatin-O-beta-D-glucopyranoside, hinokinin and bursehernin, and three natural compounds namely 3,4-dimetoxyphenyl-1-O-beta-D-(6-sulpho)-glucopyranoside, 3,4,5-trimetoxyphenyl 1-O-beta-D-(6-sulpho)-glucopyranoside and 3,4-diidroxyphenylethanol-1-O-beta-D-(6-sulpho)-glucopyranoside. Their structures were established by NMR and ESI/MS experiments. Additionally, an LC-ESI/MS qualitative study on the phenolic compounds and an LC-ESI/MS/MS quantitative study on the lignans found in the methanolic extract of B. simaruba bark were performed to give value to the plant as source of these biological active compounds. Quantitative analyses results confirmed that compounds yatein, beta-peltatin-O-beta-D-glucopyranoside, hinokinin and bursehernin are major compounds in the bark and, in particular, beta-peltatin-O-beta-D-glucopyranoside appears to be the most abundant.

  9. Mass spectrometry for malaria diagnosis.

    PubMed

    Demirev, Plamen A

    2004-11-01

    A physical method currently being developed for malaria parasite detection and diagnosis in blood is reviewed in this article. The method - direct laser desorption mass spectrometry - is based on the detection of heme (iron protoporphyrin) as a unique qualitative and quantitative molecular biomarker for malaria. In infected erythrocytes, the parasite sequesters heme in a molecular crystal (hemozoin) - a volume of highly concentrated and purified biomarker molecules. Laser desorption mass spectrometry detects only heme from hemozoin in parasite-infected blood, and not heme that is bound to hemoglobin or other proteins in uninfected blood samples. The method requires only a drop of blood with minimal sample preparation. Laser desorption mass spectrometry may become a rapid and high-throughput tool for specific and sensitive pan-malaria detection at levels below 10 parasites/mul of blood.

  10. Symposium on accelerator mass spectrometry

    SciTech Connect

    1981-01-01

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  11. Investigation of Pokemon-regulated proteins in hepatocellular carcinoma using mass spectrometry-based multiplex quantitative proteomics.

    PubMed

    Bi, Xin; Jin, Yibao; Gao, Xiang; Liu, Feng; Gao, Dan; Jiang, Yuyang; Liu, Hongxia

    2013-01-01

    Pokemon is a transcription regulator involved in embryonic development, cellular differentiation and oncogenesis. It is aberrantly overexpressed in multiple human cancers including Hepatocellular carcinoma (HCC) and is considered as a promising biomarker for HCC. In this work, the isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics strategy was used to investigate the proteomic profile associated with Pokemon in human HCC cell line QGY7703 and human hepatocyte line HL7702. Samples were labeled with four-plex iTRAQ reagents followed by two-dimensional liquid chromatography coupled with tandem mass spectrometry analysis. A total of 24 differentially expressed proteins were selected as significant. Nine proteins were potentially up-regulated by Pokemon while 15 proteins were potentially down-regulated and many proteins were previously identified as potential biomarkers for HCC. Gene ontology (GO) term enrichment revealed that the listed proteins were mainly involved in DNA metabolism and biosynthesis process. The changes of glucose-6-phosphate 1-dehydrogenase (G6PD, up-regulated) and ribonucleoside-diphosphate reductase large sub-unit (RIM1, down-regulated) were validated by Western blotting analysis and denoted as Pokemon's function of oncogenesis. We also found that Pokemon potentially repressed the expression of highly clustered proteins (MCM3, MCM5, MCM6, MCM7) which played key roles in promoting DNA replication. Altogether, our results may help better understand the role of Pokemon in HCC and promote the clinical applications.

  12. Investigation of Fundamental Physical Properties of a Polydimethylsiloxane (PDMS) Membrane using a Proton Transfer Reaction-Mass Spectrometry (PRTMS)

    SciTech Connect

    Boscaini, Elena; Alexander, M. Lizabeth; Prazeller, Peter; Mark, T. D.

    2004-12-15

    A membrane introduction proton transfer reaction mass spectrometry (MI-PTRMS) has been employed for the characterisation of a polydimethylsiloxane (PDMS) membrane. For this purpose the diffusion and partition coefficients (which serves as a measure for solubility) have been determined experimentally for different classes of chemical compounds both non-polar and polar species, i.e. aromatics, alcohols, ketones. It turned out that not only polar compounds exhibit strong interaction with a hydrophobic membrane such as the PDMS, but also non polar compounds as trimethylbenzene or propylbenzene which bear a relevant number of methyl groups or an alkyl chain show strong interaction with a PDMS membrane. Stronger interaction analyte-membrane leads to a slower diffusion coefficient and larger partition coefficient. The effect of the temperature on the diffusion coefficient and partition coefficient is also investigated. At higher temperature diffusion becomes faster and solubility lower. Permeability is calculated from diffusion and partition coefficients and activation energy are derived from corresponding Arrhenius plots. The MI-PTRMS system shows detection limits in the order of tens of pptv and it’s linear over five orders of magnitude.

  13. Investigation of early and advanced stages in ovarian cancer using human plasma by differential scanning calorimetry and mass spectrometry.

    PubMed

    Kim, Nam Ah; Jin, Jing Hui; Kim, Kyung-Hee; Lim, Dae Gon; Cheong, Heesun; Kim, Yun Hwan; Ju, Woong; Kim, Seung Cheol; Jeong, Seong Hoon

    2016-05-01

    Ovarian cancer is recognized with high mortality due to asymptomatic nature of the disease and difficulties in diagnosing early stage of the cancer. The present study evaluates the use of differential scanning calorimetry (DSC) in differentiating the severity of ovarian cancer from healthy women. 47 diseased women were subdivided into four stages with respect to clinical relevance and severity. Stages I-II were regarded as early stages and stages III-IV were regarded as advanced stages. The two average transition temperatures (T m ) increased with disease severity from 64.84 and 70.32 °C (healthy) to 68.46 and 75.24 °C (stage IV), respectively. T m were increased depending on clinical groups. In addition, the change in heat capacity was also dependent on the disease severity. To further support and investigate the nature of the proposed interactions, matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis is employed. The results suggest the differences in peptide expression between early and advanced stage of ovarian cancer, affected abundant proteins in plasma. The combined DSC and MS approach was supportive in identifying a unique signature of ovarian cancer stages, and demonstrates the potential of DSC as a complementary diagnostic tool in the evaluation of early stage ovarian cancer.

  14. Investigation of the molecular structure of the human stratum corneum ceramides [NP] and [EOS] by mass spectrometry.

    PubMed

    Hinder, A; Schmelzer, C E H; Rawlings, A V; Neubert, R H H

    2011-01-01

    The aim of this study was to characterize the two ceramide (CER) subclasses CER[NP] and CER[EOS] of human stratum corneum and to identify the chemical structures of their subspecies. High-performance thin-layer chromatography and normal-phase high-performance liquid chromatography were used for the separation of CER fractions, whereas nanoelectrospray ionization tandem mass spectrometry was applied to investigate the chemical structures in detail. Thus, CER[EOS] fragmentation revealed that in addition to linoleic acid other esterified fatty acids occur in the ω-position. Of particular interest is the identification of a 17:2 fatty acid located in this part of the molecule. Several subspecies of CER[NP], including subspecies with odd numbers of carbon atoms in both chains, the non-α-hydroxylated fatty acid moiety (part N) and the phytosphingosine (part P), were identified. Furthermore, it was found that 12% of CER[NP] subspecies have an odd number of carbon atoms in both chains of the molecule. Similar results were obtained for CER[EOS]. Both the esterified fatty acid (part E) and the sphingosine base (part S) were found to contain odd-numbered chain lengths. These results underline the heterogeneity of the CER composition in the stratum corneum lipid bilayer. Copyright © 2011 S. Karger AG, Basel.

  15. Mass spectrometry for biomarker development

    SciTech Connect

    Wu, Chaochao; Liu, Tao; Baker, Erin Shammel; Rodland, Karin D.; Smith, Richard D.

    2015-06-19

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

  16. Investigation of the origin of ephedrine and methamphetamine by stable isotope ratio mass spectrometry: a Japanese experience.

    PubMed

    Makino, Y; Urano, Y; Nagano, T

    2005-01-01

    Illicit drug abuse is a serious global problem that can only be solved through international cooperation. In Asian countries, the abuse of methamphetamine is one of the most pressing problems. To assist in the control of methamphetamine, the authors investigated in detail the character of ephedrine, which is a key precursor for the illicit manufacture of methamphetamine. Commercial ephedrine is produced by one of three methods: (a) extraction from Ephedra plants, (b) full chemical synthesis or (c) via a semi-synthetic process involving the fermentation of sugar, followed by amination. Although chemically there is no difference between ephedrine samples from different origins (natural, synthetic or semi-synthetic), scientific and analytical tools such as drug-characterization and impurity-profiling programmes may provide valuable information for law enforcement and regulatory activities as part of precursor control strategies. During the research under discussion in the present article, in addition to classical impurity profiling of manufacturing by-products, the use of stable isotope ratio mass spectrometry was investigated for determining the origin of the ephedrine that had been used as a precursor in seized methamphetamine samples. The results of carbon and nitrogen stable isotope ratio (delta13C and delta15N) analysis of samples of crystalline methamphetamine seized in Japan suggested that the drug had been synthesized from either natural or semi-synthetic ephedrine and not from synthetic ephedrine. Stable isotope ratio analysis is expected to be a useful tool for tracing the origins of seized methamphetamine. It has attracted much interest from precursor control authorities in Japan and the East Asian region and may prove useful in the international control of precursors.

  17. Combining two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy, imaging desorption electrospray ionization mass spectrometry, and direct analysis in real-time mass spectrometry for the integral investigation of counterfeit pharmaceuticals.

    PubMed

    Nyadong, Leonard; Harris, Glenn A; Balayssac, Stéphane; Galhena, Asiri S; Malet-Martino, Myriam; Martino, Robert; Parry, R Mitchell; Wang, May Dongmei; Fernández, Facundo M; Gilard, Véronique

    2009-06-15

    During the past decade, there has been a marked increase in the number of reported cases involving counterfeit medicines in developing and developed countries. Particularly, artesunate-based antimalarial drugs have been targeted, because of their high demand and cost. Counterfeit antimalarials can cause death and can contribute to the growing problem of drug resistance, particularly in southeast Asia. In this study, the complementarity of two-dimensional diffusion-ordered (1)H nuclear magnetic resonance spectroscopy (2D DOSY (1)H NMR) with direct analysis in real-time mass spectrometry (DART MS) and desorption electrospray ionization mass spectrometry (DESI MS) was assessed for pharmaceutical forensic purposes. Fourteen different artesunate tablets, representative of what can be purchased from informal sources in southeast Asia, were investigated with these techniques. The expected active pharmaceutical ingredient was detected in only five formulations via both nuclear magnetic resonance (NMR) and mass spectrometry (MS) methods. Common organic excipients such as sucrose, lactose, stearate, dextrin, and starch were also detected. The graphical representation of DOSY (1)H NMR results proved very useful for establishing similarities among groups of samples, enabling counterfeit drug "chemotyping". In addition to bulk- and surface-average analyses, spatially resolved information on the surface composition of counterfeit and genuine antimalarial formulations was obtained using DESI MS that was performed in the imaging mode, which enabled one to visualize the homogeneity of both genuine and counterfeit drug samples. Overall, this study suggests that 2D DOSY (1)H NMR, combined with ambient MS, comprises a powerful suite of instrumental analysis methodologies for the integral characterization of counterfeit antimalarials.

  18. Ion Mobility Spectrometry (IMS) and Mass Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.

    2010-04-20

    In a media of finite viscosity, the Coulomb force of external electric field moves ions with some terminal speed. This dynamics is controlled by “mobility” - a property of the interaction potential between ions and media molecules. This fact has been used to separate and characterize gas-phase ions in various modes of ion mobility spectrometry (IMS) developed since 1970. Commercial IMS devices were introduced in 1980-s for field detection of volatile traces such as explosives and chemical warfare agents. Coupling to soft-ionization sources, mass spectrometry (MS), and chromatographic methods in 1990-s had allowed IMS to handle complex samples, enabling new applications in biological and environmental analyses, nanoscience, and other areas. Since 2003, the introduction of commercial systems by major instrument vendors started bringing the IMS/MS capability to broad user community. The other major development of last decade has been the differential IMS or “field asymmetric waveform IMS” (FAIMS) that employs asymmetric time-dependent electric field to sort ions not by mobility itself, but by the difference between its values in strong and weak electric fields. Coupling of FAIMS to conventional IMS and stacking of conventional IMS stages have enabled two-dimensional separations that dramatically expand the power of ion mobility methods.

  19. Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  20. "EMERGING" POLLUTANTS, MASS SPECTROMETRY, AND ...

    EPA Pesticide Factsheets

    A foundation for Environmental Science - Mass Spectrometry: Historically fundamental to amassing our understanding of environmental processes and chemical pollution is the realm of mass spectrometry - the mainstay of analytical chemistry - the workhorse that supplies much of the definitive data that environmental scientists rely upon for identifying the molecular compositions (and ultimately the structures) of chemicals. This is not to ignore the complementary, critical roles played by the adjunct practices of sample enrichment (via any of various means of selective extraction) and analyte separation (via the myriad forms of chromatography and electrophoresis).While the power of mass spectrometry has long been highly visible to the practicing environmental chemist, it borders on continued obscurity to the lay public and most non-chemists. Even though mass spectrometry has played a long, historic (and largely invisible) role in establishing or undergirdidng our existing knowledge about environmental processes and pollution, what recognition it does enjoy is usually relegated to that of a tool. It is ususally the relevance of ssignificance of the knowledge acquired from the application of the tool that has ultimate meaning to the public and science at large - not how the knowledge was acquired. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in

  1. Mass spectrometry based in vitro assay investigations on the transformation of pharmaceutical compounds by oxidative enzymes.

    PubMed

    Stadlmair, Lara F; Letzel, Thomas; Drewes, Jörg E; Graßmann, Johanna

    2017-05-01

    The ubiquitous presence of trace organic chemicals in wastewater and surface water leads to a growing demand for novel removal technologies. The use of isolated enzymes has been shown to possess the capability for a targeted application but requires a clearer mechanistic understanding. In this study, the potential of peroxidase from horseradish (HRP) and laccase from Pleurotus ostreatus (LccPO) to transform selected trace organic chemicals was studied using mass spectrometry (MS)-based in vitro enzyme assays. Conversion by HRP appeared to be more efficient compared to LccPO. Diclofenac (DCF) and sotalol (STL) were completely transformed by HRP after 4 h and immediate conversion was observed for acetaminophen (APAP). During treatment with LccPO, 60% of DCF was still detectable after 24 h and no conversion was found for STL. APAP was completely transformed after 20 min. Sulfamethoxazole (SMX), carbamazepine (CBZ), ibuprofen (IBP) and naproxen (NAP) were insusceptible to enzymatic conversion. In pharmaceutical mixtures, HRP exhibited a preference for DCF and APAP and the generally less efficient conversion of STL was enhanced in presence of APAP. Transformation product pattern after treatment with HRP revealed polymerization products for DCF while STL showed cleavage reactions. DCF product formation shifted towards a proposed dimeric iminoquinone product in presence of APAP whereas a generally less pronounced product formation in mixtures was observed for STL. In conclusion, the enzymatic treatment approach worked selectively and efficiently for a few pharmaceuticals. However, for application the investigation and possibly immobilization of multiplex enzymes being able to transform diverse chemical structures is recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Accelerator mass spectrometry

    SciTech Connect

    Vogel, J.S.; Turteltaub, K.W.; Finkel, R.; Nelson, D.E.

    1995-06-01

    Accelerator mass spectroscopy (AMS) can be used for efficient detection of long-lived isotopes at part-per-quadrillion sensitivities with good precision. In this article we present an overview of AMS and its recent use in archaeology, geochemistry and biomolecular tracing. All AMS systems use cesium sputter ion sources to produce negative ions from a small button of a solid sample containing the element of interest, such as graphite, metal halide, or metal oxide, often mixed with a metal powder as binder and thermal conductor. Experience shows that both natural and biomedical samples are compatible in a single AMS system, but few other AMS sites make routine {sup 14}C measurements for both dating and tracing. AMS is, in one sense, just `a very sensitive decay counter`, but if AMS sensitivity is creatively coupled to analytical chemistry of certain isotopes, whole new areas of geosciences, archaeology, and life sciences can be explored. 29 refs., 2 figs., 1 tab.

  3. Mass spectrometry of aerospace materials

    NASA Technical Reports Server (NTRS)

    Colony, J. A.

    1976-01-01

    Mass spectrometry is used for chemical analysis of aerospace materials and contaminants. Years of analytical aerospace experience have resulted in the development of specialized techniques of sampling and analysis which are required in order to optimize results. This work has resulted in the evolution of a hybrid method of indexing mass spectra which include both the largest peaks and the structurally significant peaks in a concise format. With this system, a library of mass spectra of aerospace materials was assembled, including the materials responsible for 80 to 90 percent of the contamination problems at Goddard Space Flight Center during the past several years.

  4. An investigation of accelerating mode and decelerating mode constant-momentum mass spectrometry and their application to a residual gas analyzer

    NASA Technical Reports Server (NTRS)

    Ng, Y. S.

    1977-01-01

    A theoretical analysis of constant momentum mass spectrometry was made. A maximum resolving power for the decelerating mode constant momentum mass spectrometer was shown theoretically to exist for a beam of ions of known energy. A vacuum system and an electron beam ionization source was constructed. Supporting electronics for a residual gas analyzer were built. Experimental investigations of various types of accelerating and decelerating impulsive modes of a constant momentum mass spectrometer as applied to a residual gas analyzer were made. The data indicate that the resolving power for the decelerating mode is comparable to that of the accelerating mode.

  5. Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry for the Investigation of Proteins and Peptides

    NASA Astrophysics Data System (ADS)

    Burnum, Kristin E.; Frappier, Sara L.; Caprioli, Richard M.

    2008-07-01

    Mass spectrometry (MS) is an excellent technology for molecular imaging because of its high data dimensionality. MS can monitor thousands of individual molecular data channels measured as mass-to-charge (m/z). We describe the use of matrix-assisted laser desorption/ionization (MALDI) MS for the image analysis of proteins, peptides, lipids, drugs, and metabolites in tissues. We discuss the basic instrumentation and sample preparation methods needed to produce high-resolution images and high image reproducibility. Matrix-addition protocols are briefly discussed along with normal operating procedures, and selected biological and medical applications of MALDI imaging MS are described. We give examples of both two- and three-dimensional imaging, including normal mouse embryo implantation, sperm maturation in mouse epididymis, protein distributions in brain sections, protein alterations as a result of drug administration, and protein changes in brain due to neurodegeneration and tumor formation. Advantages of this technology and future challenges for its improvement are discussed.

  6. Investigating the presence of omeprazole in waters by liquid chromatography coupled to low and high resolution mass spectrometry: degradation experiments.

    PubMed

    Boix, C; Ibáñez, M; Sancho, J V; Niessen, W M A; Hernández, F

    2013-10-01

    Omeprazole is one of the most consumed pharmaceuticals around the world. However, this compound is scarcely detected in urban wastewater and surface water. The absence of this pharmaceutical in the aquatic ecosystem might be due to its degradation in wastewater treatment plants, as well as in receiving water. In this work, different laboratory-controlled degradation experiments have been carried out on surface water in order to elucidate generated omeprazole transformation products (TPs). Surface water spiked with omeprazole was subjected to hydrolysis, photo-degradation under both sunlight and ultraviolet radiation and chlorination. Analyses by liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF MS) permitted identification of up to 17 omeprazole TPs. In a subsequent step, the TPs identified were sought in surface water and urban wastewater by LC-QTOF MS and by LC coupled to tandem mass spectrometry with triple quadrupole. The parent omeprazole was not detected in any of the samples, but four TPs were found in several water samples. The most frequently detected compound was OTP 5 (omeprazole sulfide), which might be a reasonable candidate to be included in monitoring programs rather than the parent omeprazole.

  7. EMERGING POLLUTANTS, MASS SPECTROMETRY, AND ...

    EPA Pesticide Factsheets

    Historically fundamental to amassing our understanding of environmental processes and chemical pollution is the realm of mass spectrometry (MS) - the mainstay of analytical chemistry - the workhorse that supplies definitive data that environmental scientists and engineers reply upon for identifying molecular compositions (and ultimately structures) of chemicals. While the power of MS has long been visible to the practicing environmental chemist, it borders on obscurity to the lay public and many scientists. While MS has played a long, historic (and largely invisible) role in establishing our knowledge of environmental processes and pollution, what recognition it does enjoy is usually relegated to that of a tool. It is usually the relevance or significance of the knowledge acquired from the application of the tool that has ultimate meaning to the public and science at large - not how the data were acquired. Methods (736/800): Mass Spectrometry and the

  8. Investigation of the Reactivity of Oligodeoxynucleotides with Glyoxal and KMnO4 Chemical Probes by Electrospray Ionization Mass Spectrometry

    PubMed Central

    Parr, Carol; Pierce, Sarah E.; Smith, Suncerae I.; Brodbelt, Jennifer S.

    2010-01-01

    The reactions of two well-known chemical probes, glyoxal and potassium permanganate (KMnO4), with oligodeoxynucleotides were monitored by electrospray ionization (ESI) mass spectrometry to evaluate the influence of the sequence of DNA, its secondary structure, and interactions with associated ligands on the reactivity of the two probes. Glyoxal, a guanine-reactive probe, incorporated a mass shift of 58 Da, and potassium permanganate (KMnO4) is a thymine-reactive probe that resulted in a mass shift of 34 Da. The reactions depended on the accessibility of the nucleobases, and the peak abundances of the adducts in the ESI-mass spectra were used to quantify the extent of the chemical probe reactions. In this study, both mixed-base sequences were studied as well as control sequences in which one reactive site was located at the terminus or center of the oligodeoxynucleotide while the surrounding bases were a second, different nucleobase. In addition, the reactions of the chemical probes with non-covalent complexes formed between DNA and either actinomycin D or ethidium bromide, both known to interact with single strand DNA, were evaluated. PMID:21743793

  9. Elemental Composition Analysis to Investigate NOx Effects on Secondary Organic Aerosol from α-Pinene Using Ultrahigh Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lim, H. J.; Park, J. H.; Babar, Z.

    2015-12-01

    Secondary organic aerosol (SOA) accounts for 20-70% of atmospheric fine aerosol. NOx plays crucial roles in SOA formation and consequently affects the composition and yield of SOA. SOA component speciation is incomplete due to its complex composition of polar oxygenated and multifunctional species. In this study, ultrahigh resolution mass spectrometry (UHR MS) was applied to improve the understanding of NOx effects on biogenic SOA formation by identifying the elemental composition of SOA. Additional research aim was to investigate oligomer components that are considered as a driving force for SOA formation and growth. In this study α-pinene SOA from photochemical reaction was examined. SOA formation was performed in the absence and presence of NOx at dry condition (<5% RH) of room temperature (~25oC) in ~8 m3 KNU smog chamber. SOA was collected on Teflon-coated glass fiber filter, which was extracted using acetonitrile and analyzed by ultrahigh resolution 15T FT-ICR MS. UHR MS data were interpreted in various ways including molecular formula, Kendrick diagram, van Krevelen diagram, and double bond equivalent values. Substantially large fractions of them are nitrogen containing species. Thousands of individual species of SOA were identified. For SOA in the absence of NOx. intensity normalized mean O/C, H/C, N/C, OM/OC ratios were 0.43, 1.52, 0.02, and 1.68, respectively. For SOA in the presence of NOx, those ratios were 0.52, 0.95, 0.08, and 1.48, respectively. 4 different oligomer formation mechanisms (addition, H abstraction, hydrolysis and de-hydrolysis reaction) were examined on the basis of SOA compositions. Detailed discussion will be presented on the molecular structure and building block of oligomers in SOA as well as the evolution of individual elemental composition by multi-generation reactions. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-01350000).

  10. Mass spectrometry. [review of techniques

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

    1976-01-01

    Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

  11. Mass spectrometry. [review of techniques

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

    1976-01-01

    Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

  12. Glycosaminoglycan Glycomics Using Mass Spectrometry*

    PubMed Central

    Zaia, Joseph

    2013-01-01

    The fact that sulfated glycosaminoglycans (GAGs) are necessary for the functioning of all animal physiological systems drives the need to understand their biology. This understanding is limited, however, by the heterogeneous nature of GAG chains and their dynamic spatial and temporal expression patterns. GAGs have a regulated structure overlaid by heterogeneity but lack the detail necessary to build structure/function relationships. In order to provide this information, we need glycomics platforms that are sensitive, robust, high throughput, and information rich. This review summarizes progress on mass-spectrometry-based GAG glycomics methods. The areas covered include disaccharide analysis, oligosaccharide profiling, and tandem mass spectrometric sequencing. PMID:23325770

  13. INSTRUMENTS AND METHODS OF INVESTIGATION: Surface-ionization field mass-spectrometry studies of nonequilibrium surface ionization

    NASA Astrophysics Data System (ADS)

    Blashenkov, Nikolai M.; Lavrent'ev, Gennadii Ya

    2007-01-01

    The ionization of polyatomic molecules on tungsten and tungsten oxide surfaces is considered for quasiequilibrium or essentially nonequilibrium conditions (in the latter case, the term nonequilibrium surface ionization is used for adsorbate ionization). Heterogeneous reactions are supposed to proceed through monomolecular decay of polyatomic molecules or fragments of multimolecular complexes. The nonequilibrium nature of these reactions is established. The dependences of the current density of disordered ions on the surface temperature, electric field strength, and ionized particle energy distribution are obtained in analytical form. Heterogeneous dissociation energies, the ionization potentials of radicals, and the magnitude of reaction departure from equilibrium are determined from experimental data, as are energy exchange times between reaction products and surfaces, the number of molecules in molecular complexes, and the number of effective degrees of freedom in molecules and complexes. In collecting the data a new technique relying on surface-ionization field mass-spectrometry was applied.

  14. Investigating Uranium Concentrations in Groundwaters in the State of Idaho Using Kinetic Phosphorescence Analysis and Inductively Coupled Plasma Mass Spectrometry.

    PubMed

    Tkavadze, Levan; Dunker, Roy E; Brey, Richard R; Dudgeon, John

    2016-11-01

    The determination of uranium concentrations in natural water samples is of great interest due to the environmental consequences of this radionuclide. In this study, 380 groundwater samples from various locations within the state of Idaho were analyzed using two different techniques. The first method was Kinetic Phosphorescence Analysis (KPA), which gives the total uranium concentrations in water samples. The second analysis method was inductively coupled plasma mass spectrometry (ICP- MS). This method determines the total uranium concentration as well as the separate isotope concentrations of uranium. The U/U isotopic ratio was also measured for each sample to confirm that there was no depleted or enriched uranium present. The results were compared and mapped separately from each other. The study also found that in some areas of the state, natural uranium concentrations are relatively high.

  15. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    NASA Astrophysics Data System (ADS)

    Tarik, Mohamed; Lotito, Giovanni; Whitby, James A.; Koch, Joachim; Fuhrer, Katrin; Gonin, Marc; Michler, Johann; Bolli, Jean-Luc; Günther, Detlef

    2009-03-01

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  16. Coded Apertures in Mass Spectrometry.

    PubMed

    Amsden, Jason J; Gehm, Michael E; Russell, Zachary E; Chen, Evan X; Di Dona, Shane T; Wolter, Scott D; Danell, Ryan M; Kibelka, Gottfried; Parker, Charles B; Stoner, Brian R; Brady, David J; Glass, Jeffrey T

    2017-06-12

    The use of coded apertures in mass spectrometry can break the trade-off between throughput and resolution that has historically plagued conventional instruments. Despite their very early stage of development, coded apertures have been shown to increase throughput by more than one order of magnitude, with no loss in resolution in a simple 90-degree magnetic sector. This enhanced throughput can increase the signal level with respect to the underlying noise, thereby significantly improving sensitivity to low concentrations of analyte. Simultaneous resolution can be maintained, preventing any decrease in selectivity. Both one- and two-dimensional (2D) codes have been demonstrated. A 2D code can provide increased measurement diversity and therefore improved numerical conditioning of the mass spectrum that is reconstructed from the coded signal. This review discusses the state of development, the applications where coding is expected to provide added value, and the various instrument modifications necessary to implement coded apertures in mass spectrometers.

  17. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  18. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, B.D.; Fought, E.R.

    1987-11-10

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface. 8 figs.

  19. Affinity membrane introduction mass spectrometry

    SciTech Connect

    Xu, C.; Patrick, J.S.; Cooks, R.G. )

    1995-02-15

    A new technique, affinity membrane introduction mass spectrometry, is described. In this method, a chemically modified membrane is used to selectively adsorb analytes bearing a particular functional group and concentrate them from solution. Release of the bound analyte results in its transfer across the membrane and allows it to be monitored mass spectrometrically, using, in the present case, a benchtop ion trap instrument. Alkylamine-modified cellulose membranes are used to bind substituted benzaldehydes through imine formation at high pH. Release of the bound aldehyde is achieved by acid hydrolysis of the surface-bound imine. Benzaldehyde is detected with excellent specificity at 10 ppm in a complex mixture using this method. Using the enrichment capability of the membrane, a full mass spectrum of benzaldehyde can be measured at a concentration of 10 ppb. The behavior of a variety of other aldehydes is also discussed to illustrate the capabilities of the method. 21 refs., 5 figs., 2 tabs.

  20. Laser Raman spectroscopy and omegatron mass spectrometry applied to investigations of the radiochemical reactions between methane and tritium

    SciTech Connect

    Engelmann, U.; Glugla, M.; Penzhorn, R.D.; Ache, H.J. . Inst. fuer Radiochemie)

    1992-03-01

    This paper reports that the radiochemical reactions between methane and tritium were vicariously chosen for the evaluation of an omegatron type mass spectrometer and a laser Raman spectrometer in view of their analytical application in tritium systems. Assessment of the omegatron was extended beyond previous work on the quantitative analysis of all hydrogen isotopes and stable helium isotopes to include the determination of tritiated hydrocarbons. As opposed to mass spectrometry, laser Raman spectroscopy is an absolute method, which in principle is applicable to all polyatomic gases. For the employment in tritium systems an uhv-tight stainless steel gas cell using windows mounted in CF flanges with a flatness better than 1 lambda was constructed and tested. The Raman spectra of H{sub 2}, HD and D{sub 2} were measured and the pure rotation and rotation vibration branches assigned. The fundamental vibrations of methane and deuterated methanes have also been identified. First kinetic data on the {beta}-radiation induced exchange reaction between tritium and methane have been obtained with an omegatron.

  1. Metabolomic investigation of porcine muscle and fatty tissue after Clenbuterol treatment using gas chromatography/mass spectrometry.

    PubMed

    Li, Guanglei; Fu, Yuhua; Han, Xiaosong; Li, Xinyun; Li, Changchun

    2016-07-22

    Clenbuterol is a β-adrenergic agonist used as additive to increase the muscle mass of meat-producing animals. Previous studies were limited to evaluations of animal growth performance and determination of the residues. Several studies have focused on urine samples. Little information about the underlying molecular mechanisms that can explain Clenbuterol metabolism and promote energy repartition in animal muscle and fatty tissue is available. Therefore, this research aims to detect the metabolite variations in muscle and fatty tissue acquired from Chinese pigs fed with Clenbuterol using gas chromatography/mass spectrometry (GC/MS). Ten two-month old Enshi black pigs were fed under the same condition; five of which were fed with basic ration containing Clenbuterol for one month, whereas the other five pigs were fed only with basic ration. Muscle and fatty tissue were subjected to metabolomics analysis using GC/MS. Differences in metabolomic profiles between the two groups were characterized by multivariate statistical analysis. The muscle samples showed that 15 metabolites were significantly different in the Clenbuterol-treated group compared with the control group; 13 potential biomarkers were found in the fatty tissue. Most of the metabolites were associated with fatty acid metabolism and amino acid metabolism. Glycerol, phenylalanine, and leucine were the common metabolites between the muscle and fatty tissue. These metabolites may provide a new clue that contributes to the understanding of the energy reassignment induced by Clenbuterol.

  2. Investigation of pharmaceuticals in processed animal by-products by liquid chromatography coupled to high-resolution mass spectrometry.

    PubMed

    Nácher-Mestre, Jaime; Ibáñez, María; Serrano, Roque; Boix, Clara; Bijlsma, Lubertus; Lunestad, Bjørn Tore; Hannisdal, Rita; Alm, Martin; Hernández, Félix; Berntssen, Marc H G

    2016-07-01

    There is an on-going trend for developing more sustainable salmon feed in which traditionally applied marine feed ingredients are replaced with alternatives. Processed animal products (PAPs) have been re-authorized as novel high quality protein ingredients in 2013. These PAPs may harbor undesirable substances such as pharmaceuticals and metabolites which are not previously associated with salmon farming, but might cause a potential risk for feed and food safety. To control these contaminants, an analytical strategy based on a generic extraction followed by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS) using quadrupole time-of-flight mass analyzer (QTOF MS) was applied for wide scope screening. Quality control samples, consisting of PAP commodities spiked at 0.02, 0.1 and 0.2 mg/kg with 150 analytes, were injected in every sample batch to verify the overall method performance. The methodology was applied to 19 commercially available PAP samples from six different types of matrices from the EU animal rendering industry. This strategy allows assessing possible emergent risk exposition of the salmon farming industry to 1005 undesirables, including pharmaceuticals, several dyes and relevant metabolites.

  3. Space Applications of Mass Spectrometry. Chapter 31

    NASA Technical Reports Server (NTRS)

    Hoffman, John H.; Griffin, Timothy P.; Limero, Thomas; Arkin, C. Richard

    2010-01-01

    Mass spectrometers have been involved in essentially all aspects of space exploration. This chapter outlines some of these many uses. Mass spectrometers have not only helped to expand our knowledge and understanding of the world and solar system around us, they have helped to put man safely in space and expand our frontier. Mass spectrometry continues to prove to be a very reliable, robust, and flexible analytical instrument, ensuring that its use will continue to help aid our investigation of the universe and this small planet that we call home.

  4. Flow reactor and triple quadrupole mass spectrometer investigations of negative ion reactions involving nitric acid - Implications for atmospheric HNO3 detection by chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Moehler, O.; Arnold, F.

    1991-07-01

    The ion-molecule reactions on which Active Chemical Ionization Mass Spectrometry (ACIMS) measurements of atmospheric nitric acid are based are presently subjected to product-ion distribution and rate coefficient measurements. The results obtained indicate that while previous stratospheric nitric acid measurements were not impared by collisional dissociation processes, these processes may have played a major role during previous tropospheric measurements: leading to an undereestimation of nitric acid concentrations. A novel ACIMS ion source has been developed in order to avoid these problems.

  5. Preliminary investigation of the application of on-line membrane extraction of trifluoroacetic acid as an aid to improvement of negative ion electrospray mass spectrometry data.

    PubMed

    New, A P; Wolff, J C; Crabtree, S; Freitas do Santos, L; Okafo, G; Lee, J; Divan, K

    2001-04-13

    We have recently investigated the biodegradation of a number of acidic aromatic compounds that give excellent chromatography using trifluoroacetic acid (TFA) based HPLC methods. Unfortunately HPLC methods using TFA are not usually compatible with detection by negative ion mass spectrometry as TFA suppresses ionisation of the analyte during the electrospray process. We present a preliminary investigation of the use of an anion-exchange micro-membrane suppressor to remove TFA on-line post column with the aim of improvement of mass spectral data using an aromatic acid as an example, Thus LC-MS using a TFA based HPLC method with negative ion mass spectral detection is shown to be possible with good sensitivity.

  6. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new tool in diagnostic investigation of nail disorders?

    PubMed

    Pföhler, Claudia; Hollemeyer, Klaus; Heinzle, Elmar; Altmeyer, Wolfgang; Graeber, Stefan; Müller, Cornelia S L; Stark, Alexandra; Jager, Sven Uwe; Tilgen, Wolfgang

    2009-10-01

    The incidence and prevalence of onychomycosis are rising worldwide. Common diagnostic techniques often lack sensitivity or specificity. Differentiation between non-infectious nail disorders is frequently not possible. The aim of this study was to establish a better diagnostic routine procedure based on modern mass spectrometric peptide analysis techniques. One hundred and fifty-five nail samples from 145 patients with clinically suspected onychomycosis (n = 96, 62%) and without onychomycosis [e.g. nail psoriasis or nail dystrophy resulting from eczema (n = 59, 38%)] were investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peptide mass fingerprinting in comparison with standard techniques. We demonstrated that MALDI-TOF MS represents a precise, robust and fast tool in diagnostic investigation of nail disorders, which is superior to common standard methods.

  7. Neuroscience and Accelerator Mass Spectrometry

    SciTech Connect

    Palmblad, M N; Buchholz, B A; Hillegonds, D J; Vogel, J S

    2004-08-02

    Accelerator mass spectrometry (AMS) is a mass spectrometric method for quantifying rare isotopes. It has had great impact in geochronology and archaeology and is now being applied in biomedicine. AMS measures radioisotopes such as {sup 3}H, {sup 14}C, {sup 26}Al, {sup 36}Cl and {sup 41}Ca, with zepto- or attomole sensitivity and high precision and throughput, enabling safe human pharmacokinetic studies involving: microgram doses, agents having low bioavailability, or toxicology studies where administered doses must be kept low (<1 {micro}g/kg). It is used to study long-term pharmacokinetics, to identify biomolecular interactions, to determine chronic and low-dose effects or molecular targets of neurotoxic substances, to quantify transport across the blood-brain barrier and to resolve molecular turnover rates in the human brain on the timescale of decades. We will here review how AMS is applied in neurotoxicology and neuroscience.

  8. Neuroscience and accelerator mass spectrometry.

    PubMed

    Palmblad, Magnus; Buchholz, Bruce A; Hillegonds, Darren J; Vogel, John S

    2005-02-01

    Accelerator mass spectrometry (AMS) is a mass spectrometric method for quantifying rare isotopes. It has had a great impact in geochronology and archaeology and is now being applied in biomedicine. AMS measures radioisotopes such as 3H, 14C, 26Al, 36Cl and 41Ca, with zepto- or attomole sensitivity and high precision and throughput, allowing safe human pharmacokinetic studies involving microgram doses, agents having low bioavailability or toxicology studies where administered doses must be kept low (<1 microg kg(-1)). It is used to study long-term pharmacokinetics, to identify biomolecular interactions, to determine chronic and low-dose effects or molecular targets of neurotoxic substances, to quantify transport across the blood-brain barrier and to resolve molecular turnover rates in the human brain on the time-scale of decades. We review here how AMS is applied in neurotoxicology and neuroscience.

  9. Mass Spectrometry Applications for Toxicology.

    PubMed

    Mbughuni, Michael M; Jannetto, Paul J; Langman, Loralie J

    2016-12-01

    Toxicology is a multidisciplinary study of poisons, aimed to correlate the quantitative and qualitative relationships between poisons and their physiological and behavioural effects in living systems. Other key aspects of toxicology focus on elucidation of the mechanisms of action of poisons and development of remedies and treatment plans for associated toxic effects. In these endeavours, Mass spectrometry (MS) has become a powerful analytical technique with a wide range of application used in the Toxicological analysis of drugs, poisons, and metabolites of both. To date, MS applications have permeated all fields of toxicology which include; environmental, clinical, and forensic toxicology. While many different analytical applications are used in these fields, MS and its hyphenated applications such as; gas chromatography MS (GC-MS), liquid chromatography MS (LC-MS), inductively coupled plasma ionization MS (ICP-MS), tandem mass spectrometry (MS/MS and MS(n)) have emerged as powerful tools used in toxicology laboratories. This review will focus on these hyphenated MS technologies and their applications for toxicology.

  10. Mass spectrometry in combinatorial chemistry.

    PubMed

    Enjalbal, C; Martinez, J; Aubagnac, J L

    2000-01-01

    In the fast expanding field of combinatorial chemistry, profiling libraries has always been a matter of concern--as illustrated by the buoyant literature over the past seven years. Spectroscopic methods, including especially mass spectrometry and to a lesser extent IR and NMR, have been applied at different levels of combinatorial library synthesis: in the rehearsal phase to optimize the chemistry prior to library generation, to confirm library composition, and to characterize after screening each structure that exhibits positive response. Most of the efforts have been concentrated on library composition assessment. The difficulties of such analyses have evolved from the infancy of the combinatorial concept, where large mixtures were prepared, to the recent parallel syntheses of collections of discrete compounds. Whereas the complexity of the analyses has diminished, an increased degree of automation was simultaneously required to achieve efficient library component identification and quantification. In this respect, mass spectrometry has been found to be the method of choice, providing rapid, sensitive, and informative analyses, especially when coupled to chromatographic separation. Fully automated workstations able to cope with several hundreds of compounds per day have been designed. After a brief introduction to describe the combinatorial approach, library characterization will be discussed in detail, considering first the solution-based methodologies and secondly the support-bound material analyses.

  11. Mass Spectrometry Applications for Toxicology

    PubMed Central

    Mbughuni, Michael M.; Jannetto, Paul J.

    2016-01-01

    Toxicology is a multidisciplinary study of poisons, aimed to correlate the quantitative and qualitative relationships between poisons and their physiological and behavioural effects in living systems. Other key aspects of toxicology focus on elucidation of the mechanisms of action of poisons and development of remedies and treatment plans for associated toxic effects. In these endeavours, Mass spectrometry (MS) has become a powerful analytical technique with a wide range of application used in the Toxicological analysis of drugs, poisons, and metabolites of both. To date, MS applications have permeated all fields of toxicology which include; environmental, clinical, and forensic toxicology. While many different analytical applications are used in these fields, MS and its hyphenated applications such as; gas chromatography MS (GC-MS), liquid chromatography MS (LC-MS), inductively coupled plasma ionization MS (ICP-MS), tandem mass spectrometry (MS/MS and MSn) have emerged as powerful tools used in toxicology laboratories. This review will focus on these hyphenated MS technologies and their applications for toxicology. PMID:28149262

  12. Composition of dissolved organic nitrogen in continental precipitation investigated by ultra-high resolution FT-ICR mass spectrometry.

    PubMed

    Altieri, Katye E; Turpin, Barbara J; Seitzinger, Sybil P

    2009-09-15

    The atmospheric transport of fixed nitrogen (N) is a critical component of the global N cycle that has been heavily impacted by human activities. It has been shown that organic N is an important contributor to atmospheric N, but its sources and composition are largely unknown. Rainwater samples collected in New Jersey were analyzed by negative and positive ion ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Elemental compositions of 402 N-containing compounds were determined and five main groups of compound classes were identified: compounds containing carbon, hydrogen, oxygen, and N detected as positive ions (CHON+), compounds containing CHON detected as negative ions (CHON-), compounds containing CHN detected as positive ions (CHN+), and CHON compounds that contain sulfur (S) detected as both positive and negative ions (CHONS+, CHONS-, respectively). The CHON+ compound class has the largest number of compounds detected (i.e., 281), with the majority, i.e., 207, containing only one N atom. The elemental ratios of these compounds and their detection in the positive ion mode suggest that they are compounds with reduced N functionality. Known contributors to secondary organic aerosol with anthropogenic sources were also identified including organonitrate compounds and nitrooxy organosulfates.

  13. Flow microcapillary plasma mass spectrometry-based investigation of new Al-Cr-Fe complex metallic alloy passivation.

    PubMed

    Ott, N; Beni, A; Ulrich, A; Ludwig, C; Schmutz, P

    2014-03-01

    Al-Cr-Fe complex metallic alloys are new intermetallic phases with low surface energy, low friction, and high corrosion resistance down to very low pH values (0-2). Flow microcapillary plasma mass spectrometry under potentiostatic control was used to characterize the dynamic aspect of passivation of an Al-Cr-Fe gamma phase in acidic electrolytes, allowing a better insight on the parameters inducing chemical stability at the oxyhydroxide-solution interface. In sulfuric acid pH 0, low element dissolution rates (in the µg cm(-2) range after 60 min) evidenced the passive state of the Al-Cr-Fe gamma phase with a preferential over-stoichiometric dissolution of Al and Fe cations. Longer air-aging was found to be beneficial for stabilizing the passive film. In chloride-containing electrolytes, ten times higher Al dissolution rates were detected at open-circuit potential (OCP), indicating that the spontaneously formed passive film becomes unstable. However, electrochemical polarization at low passive potentials induces electrical field generated oxide film modification, increasing chemical stability at the oxyhydroxide-solution interface. In the high potential passive region, localized attack is initiated with subsequent active metal dissolution.

  14. Investigation of pharmaceuticals in Missouri natural and drinking water using high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Chuan; Shi, Honglan; Adams, Craig D; Gamagedara, Sanjeewa; Stayton, Isaac; Timmons, Terry; Ma, Yinfa

    2011-02-01

    A comprehensive method has been developed and validated in two different water matrices for the analysis of 16 pharmaceutical compounds using solid phase extraction (SPE) of water samples, followed by liquid chromatography coupled with tandem mass spectrometry. These 16 compounds include antibiotics, hormones, analgesics, stimulants, antiepileptics, and X-ray contrast media. Method detection limits (MDLs) that were determined in both reagent water and municipal tap water ranged from 0.1 to 9.9 ng/L. Recoveries for most of the compounds were comparable to those obtained using U.S. EPA methods. Treated and untreated water samples were collected from 31 different water treatment facilities across Missouri, in both winter and summer seasons, and analyzed to assess the 16 pharmaceutical compounds. The results showed that the highest pharmaceutical concentrations in untreated water were caffeine, ibuprofen, and acetaminophen, at concentrations of 224, 77.2, and 70 ng/L, respectively. Concentrations of pharmaceuticals were generally higher during the winter months, as compared to those in the summer due, presumably, to smaller water quantities in the winter, even though pharmaceutical loadings into the receiving waters were similar for both seasons. © 2010 Elsevier Ltd. All rights reserved.

  15. Investigation on the combined effect of cocaine and ethanol administration through a liquid chromatography-mass spectrometry metabolomics approach.

    PubMed

    Sánchez-López, Elena; Marcos, Alberto; Ambrosio, Emilio; Mayboroda, Oleg A; Marina, María Luisa; Crego, Antonio L

    2017-06-05

    Alcohol is the most widely consumed legal drug, whereas cocaine is the illicit psychostimulant most commonly used in Europe. The combined use of alcohol and cocaine is frequent among drug-abuse consumers and leads to further exacerbation of health consequences compared to individual consumption. The pharmacokinetic and metabolic interactions leading to an increase in their combined toxicity still remains poorly understood. Here, the first metabolomics study of combined cocaine and ethanol chronic exposure effects is reported. A Liquid Chromatography strategy based on sample derivatization with 9-fluorenylmethyloxycarbonyl chloride and using a C18 column coupled to high resolution Mass Spectrometry (time of flight analyzer) was employed to analyze plasma from rats exposed intravenously to these drugs in a 52-min analysis. Using a combination of non-supervised and supervised multivariate analysis the metabolic differences between our experimental groups were explored and unraveled. A comparative analysis of the individual models and their variable importance in the projection values have shown that every experiment intervention includes a subset of specific metabolites. Eleven of these metabolites were annotated, where eight were unequivocally identified using standards and three were tentatively identified by matching the MS/MS spectra to libraries. The results demonstrated that the affected metabolic pathways were mainly those related to the metabolism of different amino acids. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Use of liquid chromatography coupled to quadrupole time-of-flight mass spectrometry to investigate pesticide residues in fruits.

    PubMed

    Grimalt, Susana; Pozo, Oscar J; Sancho, Juan V; Hernández, Félix

    2007-04-01

    In this paper, the potential of coupling liquid chromatography with hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF) for the determination of pesticides in a variety of fruit samples (orange peel and flesh, banana skin and flesh, strawberry and pear) has been explored. The quantitative application at residue levels has been proven for two insecticides (buprofezin and hexythiazox), which were satisfactorily determined at three concentration levels, 0.1, 1, and 5 mg/kg, obtaining a suitable linearity range (correlation coefficient>0.99) of more than 2 orders of magnitude. Satisfactory recoveries have been obtained for both compounds at the three levels tested in all sample matrices, with lowest calibration levels (LCL) of 0.075 and 0.01 mg/kg. The excellent potential of QTOF for identification purposes is illustrated by the high number of identification points (IPs) earned, up to 21, at the highest concentration of 5 mg/kg, or between 11 and 21 at the 0.1 and 1 mg/kg levels. The application of LC-QTOF MS to real samples revealed the presence of several positives at concentrations close to the LCL, all of which were confirmed with more than 11 IPs. The potential of QTOF for elucidation of nontarget analytes has also been demonstrated by the finding of one transformation product (TP) of buprofezin in a banana skin sample. This TP was identified by obtaining the full scan product ion spectra at different collision energies with acceptable accurate mass deviation. The work performed in this paper illustrates the suitability and excellent confirmatory potential of LC-QTOF MS for pesticides residues analysis in food samples.

  17. Clinical Application of Ambient Ionization Mass Spectrometry

    PubMed Central

    Li, Li-Hua; Hsieh, Hua-Yi; Hsu, Cheng-Chih

    2017-01-01

    Ambient ionization allows mass spectrometry analysis directly on the sample surface under atmospheric pressure with almost zero sample pretreatment. Since the development of desorption electrospray ionization (DESI) in 2004, many other ambient ionization techniques were developed. Due to their simplicity and low operation cost, rapid and on-site clinical mass spectrometry analysis becomes real. In this review, we will highlight some of the most widely used ambient ionization mass spectrometry approaches and their applications in clinical study. PMID:28337399

  18. Nanoscale investigations of shift of individual interfaces in temperature induced processes of Ni-Si system by secondary neutral mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lakatos, A.; Langer, G. A.; Csik, A.; Cserhati, C.; Kis-Varga, M.; Daroczi, L.; Katona, G. L.; Erdélyi, Z.; Erdelyi, G.; Vad, K.; Beke, D. L.

    2010-12-01

    We describe a method for measurement of nanoscale shift of interfaces in layered systems by a combination of secondary neutral mass spectrometry and profilometer. We demonstrate it by the example of the investigation of interface shifts during the solid state reaction in Ni/amorphous-Si system. The kinetics of the shrinkage of the initial nanocrystalline Ni film and the amorphous Si layer as well as the average growth kinetics of the product phases were determined at 503 K. The results show that nanoscale resolution can be reached and the method is promising for following solid state reactions in different thin film systems.

  19. Liquid chromatography/mass spectrometry investigation of the impact of thermal processing and storage on peach procyanidins.

    PubMed

    Hong, Yun-Jeong; Barrett, Diane M; Mitchell, Alyson E

    2004-04-21

    Normal-phase liquid chromatography/mass spectrometry (LC/MS) was used to determine the levels and fate of procyanidins in frozen and canned Ross clingstone peaches as well as in the syrup used in the canning over a 3 month period. Procyanidin oligomers, monomers through undecamers, were identified in Ross clingstone peaches. Optimized methods allowed for the quantitation of oligomers through octamers. The profile of procyanidins in peaches is similar to profiles found in grapes, chocolate, and beverages linked to health benefits such as tea and wine. The monomer content in frozen peeled peaches was found to be 19.59 mg/kg. Dimers (39.59 mg/kg) and trimers (38.81 mg/kg) constituted the largest percent composition of oligomers in the peaches. Tetramers through octamers were present in levels of 17.81, 12.43, 10.62, 3.94 and 1.75 mg/kg, respectively. Thermal processing resulted in an 11% reduction in monomers, a 9% reduction in dimers, a 12% reduction in trimers, a 6% reduction in tetramers, and a 5% reduction in pentamers. Hexamers and heptamers demonstrated an approximate 30% loss, and octamers were no longer detected. Analysis of the syrup after thermal processing indicates that there is a migration of procyanidin monomers through hexamers into the syrup that can account for the losses observed during the canning process. Storage of canned peaches for 3 months demonstrated a time-related loss in higher oligomers and that by 3 months oligomers larger than tetramers are not observed. At 3 months postcanning, levels of monomers had decreased by 10%, dimers by 16%, trimers by 45%, and tetramers by 80%. A similar trend was observed in the canning syrup.

  20. Investigations in the possibility of early detection of colorectal cancer by gas chromatography/triple-quadrupole mass spectrometry.

    PubMed

    Nishiumi, Shin; Kobayashi, Takashi; Kawana, Shuichi; Unno, Yumi; Sakai, Takero; Okamoto, Koji; Yamada, Yasuhide; Sudo, Kazuki; Yamaji, Taiki; Saito, Yutaka; Kanemitsu, Yukihide; Okita, Natsuko Tsuda; Saito, Hiroshi; Tsugane, Shoichiro; Azuma, Takeshi; Ojima, Noriyuki; Yoshida, Masaru

    2017-03-07

    In developed countries, the number of patients with colorectal cancer has been increasing, and colorectal cancer is one of the most common causes of cancer death. To improve the quality of life of colorectal cancer patients, it is necessary to establish novel screening methods that would allow early detection of colorectal cancer. We performed metabolome analysis of a plasma sample set from 282 stage 0/I/II colorectal cancer patients and 291 healthy volunteers using gas chromatography/triple-quadrupole mass spectrometry in an attempt to identify metabolite biomarkers of stage 0/I/II colorectal cancer. The colorectal cancer patients included patients with stage 0 (N=79), I (N=80), and II (N=123) in whom invasion and metastasis were absent. Our analytical system detected 64 metabolites in the plasma samples, and the levels of 29 metabolites differed significantly (Bonferroni-corrected p=0.000781) between the patients and healthy volunteers. Based on these results, a multiple logistic regression analysis of various metabolite biomarkers was carried out, and a stage 0/I/II colorectal cancer prediction model was established. The area under the curve, sensitivity, and specificity values of this model for detecting stage 0/I/II colorectal cancer were 0.996, 99.3%, and 93.8%, respectively. The model's sensitivity and specificity values for each disease stage were >90%, and surprisingly, its sensitivity for stage 0, specificity for stage 0, and sensitivity for stage II disease were all 100%. Our predictive model can aid early detection of colorectal cancer and has potential as a novel screening test for cases of colorectal cancer that do not involve lymph node or distant metastasis.

  1. Investigations in the possibility of early detection of colorectal cancer by gas chromatography/triple-quadrupole mass spectrometry

    PubMed Central

    Kawana, Shuichi; Unno, Yumi; Sakai, Takero; Okamoto, Koji; Yamada, Yasuhide; Sudo, Kazuki; Yamaji, Taiki; Saito, Yutaka; Kanemitsu, Yukihide; Okita, Natsuko Tsuda; Saito, Hiroshi; Tsugane, Shoichiro; Azuma, Takeshi; Ojima, Noriyuki; Yoshida, Masaru

    2017-01-01

    In developed countries, the number of patients with colorectal cancer has been increasing, and colorectal cancer is one of the most common causes of cancer death. To improve the quality of life of colorectal cancer patients, it is necessary to establish novel screening methods that would allow early detection of colorectal cancer. We performed metabolome analysis of a plasma sample set from 282 stage 0/I/II colorectal cancer patients and 291 healthy volunteers using gas chromatography/triple-quadrupole mass spectrometry in an attempt to identify metabolite biomarkers of stage 0/I/II colorectal cancer. The colorectal cancer patients included patients with stage 0 (N=79), I (N=80), and II (N=123) in whom invasion and metastasis were absent. Our analytical system detected 64 metabolites in the plasma samples, and the levels of 29 metabolites differed significantly (Bonferroni-corrected p=0.000781) between the patients and healthy volunteers. Based on these results, a multiple logistic regression analysis of various metabolite biomarkers was carried out, and a stage 0/I/II colorectal cancer prediction model was established. The area under the curve, sensitivity, and specificity values of this model for detecting stage 0/I/II colorectal cancer were 0.996, 99.3%, and 93.8%, respectively. The model's sensitivity and specificity values for each disease stage were >90%, and surprisingly, its sensitivity for stage 0, specificity for stage 0, and sensitivity for stage II disease were all 100%. Our predictive model can aid early detection of colorectal cancer and has potential as a novel screening test for cases of colorectal cancer that do not involve lymph node or distant metastasis. PMID:28179577

  2. The absolute bioavailability investigation of LS177 in rats using ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Lunhui; Ju, Ping; Zhou, Feifei; Zhang, Yuanyuan; Zhao, Simin; Jiang, Yu; Bi, Kaishun; Chen, Xiaohui

    2015-09-01

    LS177 is a novel inhibitor of mesenchymal epithelial transition (MET) that was used as an anticancer agent. The present study was to evaluate the absolute bioavailability of LS177 in rats. A rapid and sensitive ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) method has been developed and validated for the determination of LS177 in rat plasma. LS177 and internal standard (IS, LS410) were extracted from rat plasma samples by protein precipitation (PPT) for intravenous group and liquid-liquid extraction (LLE) procedure for oral group, then separated on a Phenomenex Kinetex XB-C18 (2.1 mm I.D. × 50 mm, 2.6 µm) using a mobile phase consisting of 0.1% formic acid in acetonitrile-0.1% formic acid water with a gradient elution program. The standard curves were linear over the ranges of 5.0-2000.0 ng · mL(-1) for PPT and 1.0-200.0 ng · mL(-1) for LLE. The mean recovery of LS177 was greater than 83.4% for PPT and not less than 88.5% for LLE, respectively. The intra- and inter-day accuracy and precision were within the acceptable limits of less than 15.0% at all concentrations. The validated method was successfully applied to the bioavailability study in rat plasma of LS177 and its absolute bioavailability was 25.37%. Copyright © 2015 John Wiley & Sons, Ltd.

  3. The membrane-associated conformation of HIV-1 Nef investigated with hydrogen exchange mass spectrometry at a Langmuir monolayer

    PubMed Central

    Pirrone, Gregory F.; Emert-Sedlak, Lori A.; Wales, Thomas E.; Smithgall, Thomas E.; Kent, Michael S.; Engen, John R.

    2015-01-01

    In the companion paper to this work, we have described development of a new type of hydrogen exchange (HX) mass spectrometry (MS) measurement that integrates Langmuir monolayers. With Langmuir monolayers, the lipid packing density can be reproducibly controlled and changed as desired. Analysis of HX in proteins that may undergo conformational changes as a function of lipid packing, for example conformational rearrangements after insertion into a lipid layer, are then possible. We previously used neutron reflection to characterize just such a conformational change in the myristoylated HIV-1 Nef protein (myrNef): at high lipid packing density, myrNef could not insert into the lipids and maintained a compact conformation adjacent to the monolayer whereas at lower lipid packing density, myrNef was able to insert N-terminal arm residues causing displacement of the core domain away from the monolayer. In order to locate where conformation may have been altered by lipid association, we applied the HX MS Langmuir monolayer method to myrNef associated with monolayers of packing densities identical to those used for the prior neutron reflection measurements. The results show that the N-terminal region and the C-terminal unstructured loop undergo conformational changes when associated with a low lipid density lipid monolayer. The results are not consistent with the hypothesis of myrNef dimerization upon membrane association in the absence of other myrNef binding partners. The HX MS Langmuir monolayer method provides new and meaningful information for myrNef that helps explain necessary conformational changes required for function at the membrane. PMID:26133569

  4. Mass Spectrometry Imaging under Ambient Conditions

    PubMed Central

    Wu, Chunping; Dill, Allison L.; Eberlin, Livia S.; Cooks, R. Graham; Ifa, Demian R.

    2012-01-01

    Mass spectrometry imaging (MSI) has emerged as an important tool in the last decade and it is beginning to show potential to provide new information in many fields owing to its unique ability to acquire molecularly specific images and to provide multiplexed information, without the need for labeling or staining. In MSI, the chemical identity of molecules present on a surface is investigated as a function of spatial distribution. In addition to now standard methods involving MSI in vacuum, recently developed ambient ionization techniques allow MSI to be performed under atmospheric pressure on untreated samples outside the mass spectrometer. Here we review recent developments and applications of MSI emphasizing the ambient ionization techniques of desorption electrospray ionization (DESI), laser ablation electrospray ionization (LAESI), probe electrospray ionization (PESI), desorption atmospheric pressure photoionization (DAPPI), femtosecond laser desorption ionization (fs-LDI), laser electrospray mass spectrometry (LEMS), infrared laser ablation metastable-induced chemical ionization (IR-LAMICI), liquid microjunction surface sampling probe mass spectrometry (LMJ-SSP MS), nanospray desorption electrospray ionization (nano-DESI), and plasma sources such as the low temperature plasma (LTP) probe and laser ablation coupled to flowing atmospheric-pressure afterglow (LA-FAPA). Included are discussions of some of the features of ambient MSI including the ability to implement chemical reactions with the goal of providing high abundance ions characteristic of specific compounds of interest and the use of tandem mass spectrometry to either map the distribution of targeted molecules with high specificity or to provide additional MS information in the structural identification of compounds. We also describe the role of bioinformatics in acquiring and interpreting the chemical and spatial information obtained through MSI, especially in biological applications for tissue

  5. Ion and gas chromatography mass spectrometry investigations of organophosphates in lithium ion battery electrolytes by electrochemical aging at elevated cathode potentials

    NASA Astrophysics Data System (ADS)

    Weber, Waldemar; Wagner, Ralf; Streipert, Benjamin; Kraft, Vadim; Winter, Martin; Nowak, Sascha

    2016-02-01

    The electrochemical aging of commercial non-aqueous lithium hexafluorophosphate (LiPF6)/organic carbonate solvent based lithium ion battery electrolyte has been investigated in view of the formation of ionic and non-ionic alkylated phosphates. Subject was a solvent mixture of ethylene carbonate/ethyl methyl carbonate EC:EMC (1:1, by wt.) with 1 M LiPF6 (LP50 Selectilyte™, BASF). The analysis was carried out by ion chromatography coupled with electrospray ionization mass spectrometry (ESI-MS) for ionic compounds and (headspace) gas chromatography mass spectrometry ((HS)-GC-MS) for non-ionic compounds. The electrochemical aging was performed by galvanostatic charge/discharge cycling and potentiostatic experiments with LiNi0.5Mn1.5O4 (LMNO) as cathode material at increased cut-off potentials (>4.5 V vs. Li/Li+). A strong dependence of the formation of organophosphates on the applied electrode potential was observed and investigated by quantitative analysis of the formed phosphates. In addition, new possible "fingerprint" compounds for describing the electrolyte status were investigated and compared to existing compounds.

  6. Mass fractions of 52 trace elements and zinc/trace element content ratios in intact human prostates investigated by inductively coupled plasma mass spectrometry.

    PubMed

    Zaichick, Sofia; Zaichick, Vladimir; Nosenko, Sergey; Moskvina, Irina

    2012-11-01

    Contents of 52 trace elements in intact prostate of 64 apparently healthy 13-60-year-old men (mean age 36.5 years) were investigated by inductively coupled plasma mass spectrometry. Mean values (M ± SΕΜ) for mass fraction (in milligrams per kilogram, on dry-weight basis) of trace elements were as follows: Ag 0.041 ± 0.005, Al 36 ± 4, Au 0.0039 ± 0.0007, B 0.97 ± 0.13, Be 0.00099 ± 0.00006, Bi 0.021 ± 0.008, Br 29 ± 3, Cd 0.78 ± 0.09, Ce 0.028 ± 0.004, Co 0.035 ± 0.003, Cs 0.034 ± 0.003, Dy 0.0031 ± 0.0005, Er 0.0018 ± 0.0004, Gd 0.0030 ± 0.0005, Hg 0.046 ± 0.006, Ho 0.00056 ± 0.00008, La 0.074 ± 0.015, Li 0.040 ± 0.004, Mn 1.53 ± 0.09, Mo 0.30 ± 0.03, Nb 0.0051 ± 0.0009, Nd 0.013 ± 0.002, Ni 4.3 ± 0.7, Pb 1.8 ± 0.4, Pr 0.0033 ± 0.0004, Rb 15.9 ± 0.6, Sb 0.040 ± 0.005, Se 0.73 ± 0.03, Sm 0.0027 ± 0.0004, Sn 0.25 ± 0.05, Tb 0.00043 ± 0.00009, Th 0.0024 ± 0.0005, Tl 0.0014 ± 0.0001, Tm 0.00030 ± 0.00006, U 0.0049 ± 0.0014, Y 0.019 ± 0.003, Yb 0.0015 ± 0.0002, Zn 782 ± 97, and Zr 0.044 ± 0.009, respectively. The upper limit of mean contents of As, Cr, Eu, Ga, Hf, Ir, Lu, Pd, Pt, Re, Ta, and Ti were the following: As ≤ 0.018, Cr ≤ 0.64, Eu ≤ 0.0006, Ga ≤ 0.08, Hf ≤ 0.02, Ir ≤ 0.0004, Lu ≤ 0.00028, Pd ≤ 0.007, Pt ≤ 0.0009, Re ≤ 0.0015, Ta ≤ 0.005, and Ti ≤ 2.6. In all prostate samples, the content of Te was under detection limit (<0.003). Additionally, ratios of the Zn content to other trace element contents as well as correlations between Zn and trace elements were calculated. Our data indicate that the human prostate accumulates such trace elements as Al, Au, B, Br, Cd, Cr, Ga, Li, Mn, Ni, Pb, U, and Zn. No special relationship between Zn and other trace elements was found.

  7. Counting Molecules by Desorption Ionization and Mass Spectrometry/Mass Spectrometry.

    ERIC Educational Resources Information Center

    Cooks, R. G.; Busch, K. L.

    1982-01-01

    Discusses two newer methods in mass spectrometry and shows how they can increase signal and signal-to-noise ratios, respectively. The first method, desorption ionization (DI), increases sensitivity while the second method, mass spectrometry/mass spectrometry (MS/MS), increases specificity. Together, the two methods offer improved analytical…

  8. Structural investigation and elucidation of new communesins from a marine-derived Penicillium expansum Link by liquid chromatography/electrospray ionization mass spectrometry.

    PubMed

    Kerzaon, Isabelle; Pouchus, Yves F; Monteau, Fabrice; Le Bizec, Bruno; Nourrisson, Marie-Renée; Biard, Jean-François; Grovel, Olivier

    2009-12-01

    Penicillium expansum is a ubiquitous species for which there are only few reports for chemical investigation in marine environments. Among the numerous secondary metabolites produced by this species, communesins represent a new class of cytotoxic and insecticidal indole alkaloids. In this study, we investigated a marine P. expansum strain exhibiting neuroactivity on a Diptera larvae bioassay. Bio-guided purification led to the isolation and the identification of communesin B as the main active compound by HRMS and 1H and 13C NMR. Liquid chromatography analyses with detection by electrospray ionization coupled with tandem mass spectrometry (LC/ESI-MS/MS) and high-resolution tandem mass spectrometry (LC/HRMS/MS) allowed the identification and characterization of four other known communesins (A, D, E and F) in the crude extract. A fragmentation model for dimethyl epoxide communesins was proposed after detailed interpretation of their MS/MS spectra. Further analyses of the extract using the modelled fragmentations led to the detection of seven new communesins found as minor compounds. Chemical structural elucidation of these new derivatives is discussed based on their fragmentation characteristics.

  9. Fast ion mass spectrometry and charged particle spectrography investigations of transverse ion acceleration and beam-plasma interactions

    NASA Technical Reports Server (NTRS)

    Gibson, W. C.; Tomlinson, W. M.; Marshall, J. A.

    1987-01-01

    Ion acceleration transverse to the magnetic field in the topside ionosphere was investigated. Transverse acceleration is believed to be responsible for the upward-moving conical ion distributions commonly observed along auroral field lines at altitudes from several hundred to several thousand kilometers. Of primary concern in this investigation is the extent of these conic events in space and time. Theoretical predictions indicate very rapid initial heating rates, depending on the ion species. These same theories predict that the events will occur within a narrow vertical region of only a few hundred kilometers. Thus an instrument with very high spatial and temporal resolution was required; further, since different heating rates were predicted for different ions, it was necessary to obtain composition as well as velocity space distributions. The fast ion mass spectrometer (FIMS) was designed to meet these criteria. This instrument and its operation is discussed.

  10. Jarosite as a Storage Mineral for Small Organic Molecules: Investigations of Natural Samples Using an 'In Situ' Laser Desorption Fourier Transform Mass Spectrometry Technique

    NASA Astrophysics Data System (ADS)

    Kotler, J. M.; Hinman, N. W.; Yan, B.; Stoner, D. L.; Scott, J. R.

    2007-03-01

    The use of laser desorption Fourier transform mass spectrometry has revealed the presence of organic matter in several jarosite samples from various locations worldwide including jarosite precipitated in the lab by acidothiobacillus ferroxidans.

  11. Applications of Mass Spectrometry to Lipids and Membranes

    PubMed Central

    Harkewicz, Richard; Dennis, Edward A.

    2012-01-01

    Lipidomics, a major part of metabolomics, constitutes the detailed analysis and global characterization, both spatial and temporal, of the structure and function of lipids (the lipidome) within a living system. As with proteomics, mass spectrometry has earned a central analytical role in lipidomics, and this role will continue to grow with technological developments. Currently, there exist two mass spectrometry-based lipidomics approaches, one based on a division of lipids into categories and classes prior to analysis, the “comprehensive lipidomics analysis by separation simplification” (CLASS), and the other in which all lipid species are analyzed together without prior separation, shotgun. In exploring the lipidome of various living systems, novel lipids are being discovered, and mass spectrometry is helping characterize their chemical structure. Deuterium exchange mass spectrometry (DXMS) is being used to investigate the association of lipids and membranes with proteins and enzymes, and imaging mass spectrometry (IMS) is being applied to the in situ analysis of lipids in tissues. PMID:21469951

  12. Application of Ion Mobility-Mass Spectrometry to the Study of Ionic Clusters: Investigation of Cluster Ions with Stable Sizes and Compositions

    PubMed Central

    Ohshimo, Keijiro; Komukai, Tatsuya; Takahashi, Tohru; Norimasa, Naoya; Wu, Jenna Wen Ju; Moriyama, Ryoichi; Koyasu, Kiichirou; Misaizu, Fuminori

    2014-01-01

    Stable cluster sizes and compositions have been investigated for cations and anions of ionic bond clusters such as alkali halides and transition metal oxides by ion mobility-mass spectrometry (IM-MS). Usually structural information of ions can be obtained from collision cross sections determined in IM-MS. In addition, we have found that stable ion sizes or compositions were predominantly produced in a total ion mass spectrum, which was constructed from the IM-MS measurement. These stable species were produced as a result of collision induced dissociations of the ions in a drift cell. We have confirmed this result in the sodium fluoride cluster ions, in which cuboid magic number cluster ions were predominantly observed. Next the stable compositions, which were obtained for the oxide systems of the first row transition metals, Ti, Fe, and Co, are characteristic for each of the metal oxide cluster ions. PMID:26819887

  13. Thermal rearrangement of 1,4-dinitroimidazole to 2,4-dinitroimidazole. Characterization and investigation of the mechanism by mass spectrometry and isotope labeling

    SciTech Connect

    Bulusu, S.; Damavarapu, R.; Autera, J.R.; Behrens, R. Jr.; Minier, L.M.; Villanueva, J.; Jayasuriya, K.; Axenrod, T.

    1995-04-06

    The thermal rearrangement of 1,4-dinitroimidazole to 2,4-dinitroimidazole has been investigated by differential scanning calorimetry and mass spectrometry techniques. When mixtures of independently prepared deuterium-and {sup 15}N-labeled samples of the 1,4-isomer were subjected to thermal rearrangement, the resulting 2,4-dinitroimidazole failed to show isotope-scrambled molecular ions in its mass spectrum, suggesting that the reaction was intramolecular in nature. This was interpreted to mean that the mechanism was of the (1,5)-sigmatropic type rearrangement. Extensive NMR measurements were used to obtain unequivocal evidence for the identity of the assumed structures of the isomeric dinitroimidazoles. Two byproducts (4-nitroimidazole and a trinitroimidazole), formed during the rearrangement reaction, have also been identified. Plausible mechanisms for their formation are discussed. 15 refs., 3 figs., 3 tabs.

  14. Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry.

    PubMed

    Malmborg, V B; Eriksson, A C; Shen, M; Nilsson, P; Gallo, Y; Waldheim, B; Martinsson, J; Andersson, Ö; Pagels, J

    2017-02-07

    To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C5-containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.

  15. Inorganic trace analysis by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Becker, Johanna Sabine; Dietze, Hans-Joachim

    1998-10-01

    Mass spectrometric methods for the trace analysis of inorganic materials with their ability to provide a very sensitive multielemental analysis have been established for the determination of trace and ultratrace elements in high-purity materials (metals, semiconductors and insulators), in different technical samples (e.g. alloys, pure chemicals, ceramics, thin films, ion-implanted semiconductors), in environmental samples (waters, soils, biological and medical materials) and geological samples. Whereas such techniques as spark source mass spectrometry (SSMS), laser ionization mass spectrometry (LIMS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) have multielemental capability, other methods such as thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have been used for sensitive mono- or oligoelemental ultratrace analysis (and precise determination of isotopic ratios) in solid samples. The limits of detection for chemical elements using these mass spectrometric techniques are in the low ng g -1 concentration range. The quantification of the analytical results of mass spectrometric methods is sometimes difficult due to a lack of matrix-fitted multielement standard reference materials (SRMs) for many solid samples. Therefore, owing to the simple quantification procedure of the aqueous solution, inductively coupled plasma mass spectrometry (ICP-MS) is being increasingly used for the characterization of solid samples after sample dissolution. ICP-MS is often combined with special sample introduction equipment (e.g. flow injection, hydride generation, high performance liquid chromatography (HPLC) or electrothermal vaporization) or an off-line matrix separation and enrichment of trace impurities (especially for characterization of

  16. Characterization of microbial siderophores by mass spectrometry.

    PubMed

    Pluháček, Tomáš; Lemr, Karel; Ghosh, Dipankar; Milde, David; Novák, Jiří; Havlíček, Vladimír

    2016-01-01

    Siderophores play important roles in microbial iron piracy, and are applied as infectious disease biomarkers and novel pharmaceutical drugs. Inductively coupled plasma and molecular mass spectrometry (ICP-MS) combined with high resolution separations allow characterization of siderophores in complex samples taking advantages of mass defect data filtering, tandem mass spectrometry, and iron-containing compound quantitation. The enrichment approaches used in siderophore analysis and current ICP-MS technologies are reviewed. The recent tools for fast dereplication of secondary metabolites and their databases are reported. This review on siderophores is concluded with their recent medical, biochemical, geochemical, and agricultural applications in mass spectrometry context.

  17. Mass Spectrometry Imaging Quick View

    SciTech Connect

    2013-01-24

    MSI QuickView is a software designed to provide a graphical user interface (GUI) for greatly speeding up experimental feedback (visualization and analysis) of mass spectrometry imaging (MSI or IMS) data during data acquisition. Often different software loads the entire data set, i.e., all lines of data into computer memory (RAM). This causes out of memory errors for larger datasets. We solved this in MSI QuickView by reading in the data one line at a time. Only the required information (e.g. the final pixel values for that line of heat map) is maintained in RAM. Interim analysis options include the mean intensity vs. m/z spectrum, intensity vs. time spectrums for up to 6 different m/z values or ranges chosen by the user and heat maps for each line. This assists in validating the usefulness of the particular experiment after scanning the first few lines. In addition, the tool facilitates further processing and analysis of the massive datasets. The user can manually pick different m/z values, time ranges, scroll through the spectra for any line in the data without having to load it in manually, save multiple images, change aspect ratios for the heat maps, and process the heat maps in multiple ways including overlaying images at different m/z values, displaying up to 9 different heat maps, alignment of scans along each line etc. There is no manipulation of the data required by the user to visualize the data.

  18. Mass spectrometry of extracellular vesicles.

    PubMed

    Pocsfalvi, Gabriella; Stanly, Christopher; Vilasi, Annalisa; Fiume, Immacolata; Capasso, Giovambattista; Turiák, Lilla; Buzas, Edit I; Vékey, Károly

    2016-01-01

    The review briefly summaries main features of extracellular vesicles, a joint terminology for exosomes, microvesicles, and apoptotic vesicles. These vesicles are in the center of interest in biology and medical sciences, and form a very active field of research. Mass spectrometry (MS), with its specificity and sensitivity, has the potential to identify and characterize molecular composition of these vesicles; but as yet there are only a limited, but fast-growing, number of publications that use MS workflows in this field. MS is the major tool to assess protein composition of extracellular vesicles: qualitative and quantitative proteomics approaches are both reviewed. Beside proteins, lipid and metabolite composition of vesicles might also be best assessed by MS techniques; however there are few applications as yet in this respect. The role of alternative analytical approaches, like gel-based proteomics and antibody-based immunoassays, are also mentioned. The objective of the review is to give an overview of this fast-growing field to help orient MS-based research on extracellular vesicles. © 2015 Wiley Periodicals, Inc.

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

    PubMed

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

    2013-02-01

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

  20. Mass spectrometry innovations in drug discovery and development.

    PubMed

    Papac, D I; Shahrokh, Z

    2001-02-01

    This review highlights the many roles mass spectrometry plays in the discovery and development of new therapeutics by both the pharmaceutical and the biotechnology industries. Innovations in mass spectrometer source design, improvements to mass accuracy, and implementation of computer-controlled automation have accelerated the purification and characterization of compounds derived from combinatorial libraries, as well as the throughput of pharmacokinetics studies. The use of accelerator mass spectrometry, chemical reaction interface-mass spectrometry and continuous flow-isotope ratio mass spectrometry are promising alternatives for conducting mass balance studies in man. To meet the technical challenges of proteomics, discovery groups in biotechnology companies have led the way to development of instruments with greater sensitivity and mass accuracy (e.g., MALDI-TOF, ESI-Q-TOF, Ion Trap), the miniaturization of separation techniques and ion sources (e.g., capillary HPLC and nanospray), and the utilization of bioinformatics. Affinity-based methods coupled to mass spectrometry are allowing rapid and selective identification of both synthetic and biological molecules. With decreasing instrument cost and size and increasing reliability, mass spectrometers are penetrating both the manufacturing and the quality control arenas. The next generation of technologies to simplify the investigation of the complex fate of novel pharmaceutical entities in vitro and in vivo will be chip-based approaches coupled with mass spectrometry.

  1. Oligomers formed through in-cloud methylglyoxal reactions: Chemical composition, properties, and mechanisms investigated by ultra-high resolution FT-ICR mass spectrometry

    NASA Astrophysics Data System (ADS)

    Altieri, K. E.; Seitzinger, S. P.; Carlton, A. G.; Turpin, B. J.; Klein, G. C.; Marshall, A. G.

    Secondary organic aerosol (SOA) is a substantial component of total atmospheric organic particulate matter, but little is known about the composition of SOA formed through cloud processing. We conducted aqueous phase photo-oxidation experiments of methylglyoxal and hydroxyl radical to simulate cloud processing. In addition to predicted organic acid monomers, oligomer formation from methylglyoxal-hydroxyl radical reactions was detected by electrospray ionization mass spectrometry (ESI-MS). The chemical composition of the oligomers and the mechanism of their formation were investigated by ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and LCQ DUO ion trap mass spectrometry (ESI-MS-MS). Reaction products included 415 compounds detected in the mass range 245-800 Da and the elemental composition of all 415 compounds were determined by ultra-high resolution FT-ICR MS. The ratio of total organic molecular weight per organic carbon weight (OM:OC) of the oligomers (1.0-2.5) was lower than the OM:OC of the organic acid monomers (2.3-3.8) formed, suggesting that the oligomers are less hygroscopic than the organic acid monomers formed from methylglyoxal-hydroxyl radical reaction. The OM:OC of the oligomers (average=2.0) is consistent with that of aged atmospheric aerosols and atmospheric humic-like substances (HULIS). A mechanism is proposed in which the organic acid monomers formed through hydroxyl radical reactions oligomerize through esterification. The mechanism is supported by the existence of series of oligomers identified by elemental composition from FT-ICR MS and ion fragmentation patterns from ESI-MS-MS. Each oligomer series starts with an organic acid monomer formed from hydroxyl radical oxidation, and increases in molecular weight and total oxygen content through esterification with a hydroxy acid (C 3H 6O 3) resulting in multiple additions of 72.02113 Da (C 3H 4O 2) to the parent organic acid monomer. Methylglyoxal is

  2. Broadband Analysis of Bioagents by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Fenselau, Catherine; Wynne, Colin; Edwards, Nathan

    Mass spectrometry was first reported to provide analysis of intact metabolite biomarkers from whole cells in 1975.1 Since then advances in ionization techniques have extended our capabilities to polar lipids and, eventually, to proteins.2, 3 Mass spectrometry provides a broadband detection system, which, however, has great specificity. Bioinformatics plays an important role in providing flexible and rapid characterization of species, based on protein and peptide mass spectra collected in the field.

  3. Mass spectrometry analysis of nucleosides and nucleotides.

    PubMed

    Dudley, Ed; Bond, Liz

    2014-01-01

    Mass spectrometry has been widely utilised in the study of nucleobases, nucleosides and nucleotides as components of nucleic acids and as bioactive metabolites in their own right. In this review, the application of mass spectrometry to such analysis is overviewed in relation to various aspects regarding the analytical mass spectrometric and chromatographic techniques applied and also the various applications of such analysis. © 2013 Wiley Periodicals, Inc.

  4. Application of mass spectrometry in proteomics.

    PubMed

    Guerrera, Ida Chiara; Kleiner, Oliver

    2005-01-01

    Mass spectrometry has arguably become the core technology in proteomics. The application of mass spectrometry based techniques for the qualitative and quantitative analysis of global proteome samples derived from complex mixtures has had a big impact in the understanding of cellular function. Here, we give a brief introduction to principles of mass spectrometry and instrumentation currently used in proteomics experiments. In addition, recent developments in the application of mass spectrometry in proteomics are summarised. Strategies allowing high-throughput identification of proteins from highly complex mixtures include accurate mass measurement of peptides derived from total proteome digests and multidimensional peptide separations coupled with mass spectrometry. Mass spectrometric analysis of intact proteins permits the characterisation of protein isoforms. Recent developments in stable isotope labelling techniques and chemical tagging allow the mass spectrometry based differential display and quantitation of proteins, and newly established affinity procedures enable the targeted characterisation of post-translationally modified proteins. Finally, advances in mass spectrometric imaging allow the gathering of specific information on the local molecular composition, relative abundance and spatial distribution of peptides and proteins in thin tissue sections.

  5. Mechanistic investigation of the interaction between bisquaternary antimicrobial agents and phospholipids by liquid secondary ion mass spectrometry and differential scanning calorimetry.

    PubMed

    Pashynskaya, V A; Kosevich, M V; Gömöry, A; Vashchenko, O V; Lisetski, L N

    2002-01-01

    Mechanisms of interaction between the antimicrobial drugs decamethoxinum and aethonium, which are based on bisquaternary ammonium compounds, and a phospholipid component of biological membranes, dipalmitoylphosphatidylcholine, were studied by means of liquid secondary ion mass spectrometry (LSIMS) and differential scanning calorimetry (DSC). Supramolecular complexes of the drugs with this phospholipid were recorded under secondary ion mass spectrometric conditions. The dependence of the structures of these complexes on structural parameters of the dications of the bisquaternary ammonium compounds was demonstrated. Tandem mass spectrometric investigations of the metastable decay of doubly charged ions of decamethoxinum and aethonium complexes with dipalmitoylphosphatidylcholine allowed estimation of structural parameters of these complexes in the gas phase. Interactions of decamethoxinum and aethonium with model membrane assemblies built from hydrated dipalmitoylphosphatidylcholine were studied using DSC. It was shown that while both drugs can interact with model membranes, the mechanisms of such interactions for decamethoxinum and aethonium differ. The correlation between the nature of these interactions and structural and electronic parameters of the dications of the two bisquaternary agents is discussed. Interpretation of combined mass spectrometric and calorimetric experimental data led to proposals that the molecular mechanisms of antimicrobial action of bisquaternary ammonium compounds are related to their effect on the membrane phospholipid components of microbial cells.

  6. Mass Spectrometry on Future Mars Landers

    NASA Technical Reports Server (NTRS)

    Brinckerhoff, W. B.; Mahaffy, P. R.

    2011-01-01

    Mass spectrometry investigations on the 2011 Mars Science Laboratory (MSL) and the 2018 ExoMars missions will address core science objectives related to the potential habitability of their landing site environments and more generally the near-surface organic inventory of Mars. The analysis of complex solid samples by mass spectrometry is a well-known approach that can provide a broad and sensitive survey of organic and inorganic compounds as well as supportive data for mineralogical analysis. The science value of such compositional information is maximized when one appreciates the particular opportunities and limitations of in situ analysis with resource-constrained instrumentation in the context of a complete science payload and applied to materials found in a particular environment. The Sample Analysis at Mars (SAM) investigation on MSL and the Mars Organic Molecule Analyzer (MOMA) investigation on ExoMars will thus benefit from and inform broad-based analog field site work linked to the Mars environments where such analysis will occur.

  7. Characterization of the triphenylphosphonium derivative of peptides by fast atom bombardment-tandem mass spectrometry, and investigations of the mechanisms of fragmentation of peptides

    SciTech Connect

    Wagner, D.S.

    1992-01-01

    Fast atom bombardment collisionally activated dissociation tandem mass spectrometry is a powerful technique for the determination of the primary structure of peptides. However, there are factors that frequently prevent successful sequence analysis by mass spectrometry. Two such factors are the poor ionization efficiency of some hydrophilic peptides and, for many peptides, ambiguities in interpretation of the spectra when key sequence ions are weak or absent. Novel and simple procedures for preparing ethyl-triphenylphosphonium derivatives of peptides are described. These procedures allow an ethyl-triphenylphosphonium moiety to be selectively attached to either the N- or C-terminus. Modification of peptides by these chemical methods significantly enhances the efficiency of fast atom bombardment ionization. Moreover, upon collisionally activated dissociation, the derivatized peptides generate a predictable series of sequence ions from either the C-terminus or the N-terminus, depending on the location of the ethyl-triphenylphosphonium moiety. The potential utility of the ethyl-triphenylphosphonium derivative in structure elucidation is illustrated by a comparison of the mass spectra of underivatized and derivatized peptides containing up to 20 amino acid residues, or contain an N-terminal blocking group, or contain a phosphate group, or contain a disulfide bond, or contain a backbone modification. When protonated peptide molecules and cationized peptide molecules are subjected to high-energy collisionally activated dissociation, skeletal bonds cleave generating sequence-specific fragment ions. These bond cleavages usually involve H-shifts. The utility of selective deuterium labeling was applied here to elucidate fragmentation mechanisms. Skeletal bond cleavages in the ionized peptide H-VGVAPG-OH were investigated, in which the molecule was analyzed in the protonated form, cationized form, or as the charge-localized ethyl-triphenylphosphonium derivative.

  8. Investigation of the selective androgen receptor modulators S1, S4 and S22 and their metabolites in equine plasma using high-resolution mass spectrometry.

    PubMed

    Hansson, Annelie; Knych, Heather; Stanley, Scott; Thevis, Mario; Bondesson, Ulf; Hedeland, Mikael

    2016-04-15

    Selective androgen receptor modulators (SARMs) are prohibited in sports due to their performance enhancing ability. It is important to investigate the metabolism to determine appropriate targets for doping control. This is the first study where the equine metabolites of SARMs S1, S4 (Andarine) and S22 (Ostarine) have been studied in plasma. Each SARM was administered to three horses as an intravenous bolus dose and plasma samples were collected. The samples were pretreated with protein precipitation using cold acetonitrile before separation by liquid chromatography. The mass spectrometric analysis was performed using negative electrospray, quadrupole time-of-flight mass spectrometry operated in MS(E) mode and triple-quadrupole mass spectrometry operated in selected reaction monitoring mode. For the quantification of SARM S1, a deuterated analogue was used as internal standard. The numbers of observed metabolites were eight, nine and four for the SARMs S1, S4 and S22, respectively. The major metabolite was formed by the same metabolic reactions for all three SARMs, namely amide hydrolysis, hydroxylation and sulfonation. The values of the determined maximum plasma concentrations were in the range of 97-170 ng/mL for SARM S1, 95-115 ng/mL for SARM S4 and 92-147 ng/mL for SARM S22 and the compounds could be detected for 96 h, 12 h and 18 h, respectively. The maximum plasma concentration of SARMs S1, S4 and S22 was measured in the first sample (5 min) after administration and they were eliminated fast from plasma. The proposed targets to be used in equine doping control are the parent compounds for all three SARMs, but with the metabolite yielding the highest response as a complementary target. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Ion chromatography electrospray ionization mass spectrometry method development and investigation of lithium hexafluorophosphate-based organic electrolytes and their thermal decomposition products.

    PubMed

    Kraft, Vadim; Grützke, Martin; Weber, Waldemar; Winter, Martin; Nowak, Sascha

    2014-08-08

    A method based on the coupling of ion chromatography (IC) and electrospray ionization mass spectrometry (ESI-MS) for the separation and determination of thermal decomposition products of LiPF6-based organic electrolytes is presented. The utilized electrolytes, LP30 and LP50, are commercially available and consist of 1mol/l LiPF6 dissolved in ethylene carbonate/dimethyl carbonate and ethylene carbonate/ethyl methyl carbonate, respectively. For the separation method development three ion chromatographic columns with different capacity and stationary phase were used and compared. Besides the known hydrolysis products of lithium hexafluorophosphate, several new organophosphates were separated and identified with the developed IC-ESI-MS method during aging investigations of the electrolytes. The chemical structures were elucidated with IC-ESI-MS/MS.

  10. Structure investigation of sertraline drug and its iodine product using mass spectrometry, thermal analyses and MO-calculations

    NASA Astrophysics Data System (ADS)

    Zayed, M. A.; Hawash, M. F.; Fahmey, M. A.; El-Habeeb, Abeer A.

    2007-11-01

    Sertraline (C 17H 17Cl 2N) as an antidepressant drug was investigated using thermal analysis (TA) measurements (TG/DTG and DTA) in comparison with electron impact (EI) mass spectral (MS) fragmentation at 70 eV. Semi-empirical MO-calculations, using PM3 procedure, has been carried out on neutral molecule and positively charged species. These calculations included bond length, bond order, bond strain, partial charge distribution and heats of formation (Δ Hf). Also, in the present work sertraline-iodine product was prepared and its structure was investigated using elemental analyses, IR, 1H NMR, 13C NMR, MS and TA. It was also subjected to molecular orbital calculations (MOC) in order to confirm its fragmentation behavior by both MS and TA in comparison with the sertraline parent drug. In MS of sertraline the initial rupture occurred was CH 3NH 2+ fragment ion via H-rearrangement while in sertraline-iodine product the initial rupture was due to the loss of I + and/or HI + fragment ions followed by CH 2dbnd NH + fragment ion loss. In thermal analyses (TA) the initial rupture in sertraline is due to the loss of C 6H 3Cl 2 followed by the loss of CH 3-NH forming tetraline molecule which thermally decomposed to give C 4H 8, C 6H 6 or the loss of H 2 forming naphthalene molecule which thermally sublimated. In sertraline-iodine product as a daughter the initial thermal rupture is due to successive loss of HI and CH 3NH followed by the loss of C 6H 5HI and HCl. Sertraline biological activity increases with the introduction of iodine into its skeleton. The activities of the drug and its daughter are mainly depend upon their fragmentation to give their metabolites in vivo systems, which are very similar to the identified fragments in both MS and TA. The importance of the present work is also due to the decision of the possible mechanism of fragmentation of the drug and its daughter and its confirmation by MOC.

  11. Investigation of the persistence of nerve agent degradation analytes on surfaces through wipe sampling and detection with ultrahigh performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Willison, Stuart A

    2015-01-20

    The persistence of chemical warfare nerve agent degradation analytes on surfaces is important, from indicating the presence of nerve agent on a surface to guiding environmental restoration of a site after a release. Persistence was investigated for several chemical warfare nerve agent degradation analytes on indoor surfaces and presents an approach for wipe sampling of surfaces, followed by wipe extraction and liquid chromatography-tandem mass spectrometry detection. Commercially available wipe materials were investigated to determine optimal wipe recoveries. Tested surfaces included porous/permeable (vinyl tile, painted drywall, and wood) and largely nonporous/impermeable (laminate, galvanized steel, and glass) surfaces. Wipe extracts were analyzed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). UPLC provides a separation of targeted degradation analytes in addition to being nearly four times faster than high-performance liquid chromatography, allowing for greater throughput after a large-scale contamination incident and subsequent remediation events. Percent recoveries from nonporous/impermeable surfaces were 60-103% for isopropyl methylphosphonate (IMPA), GB degradate; 61-91% for ethyl methylphosphonate (EMPA), VX degradate; and 60-98% for pinacolyl methylphosphonate (PMPA), GD degradate. Recovery efficiencies for methyl phosphonate (MPA), nerve agent degradate, and ethylhydrogen dimethylphosphonate (EHDMAP), GA degradate, were lower, perhaps due to matrix effects. Diisopropyl methylphosphonate, GB impurity, was not recovered from surfaces. The resulting detection limits for wipe extracts were 0.065 ng/cm(2) for IMPA, 0.079 ng/cm(2) for MPA, 0.040 ng/cm(2) for EMPA, 0.078 ng/cm(2) for EHDMAP, and 0.013 ng/cm(2) for PMPA. The data indicate that laboratories may hold wipe samples for up to 30 days prior to analysis. Target analytes were observed to persist on surfaces for at least 6 weeks.

  12. Methods for recalibration of mass spectrometry data

    DOEpatents

    Tolmachev, Aleksey V.; Smith, Richard D.

    2009-03-03

    Disclosed are methods for recalibrating mass spectrometry data that provide improvement in both mass accuracy and precision by adjusting for experimental variance in parameters that have a substantial impact on mass measurement accuracy. Optimal coefficients are determined using correlated pairs of mass values compiled by matching sets of measured and putative mass values that minimize overall effective mass error and mass error spread. Coefficients are subsequently used to correct mass values for peaks detected in the measured dataset, providing recalibration thereof. Sub-ppm mass measurement accuracy has been demonstrated on a complex fungal proteome after recalibration, providing improved confidence for peptide identifications.

  13. Universal Mass Spectrometry-Based Life Detection

    NASA Astrophysics Data System (ADS)

    Cleaves, H. J.; Giri, C.

    2017-02-01

    The search for ET life will be an important 21st century solar system exploration goal. Mass spectrometry offers a comprehensive, rapid way of "chemotyping" environmental samples. Preparation of a reference catalogue of abiotic and biological samples is described.

  14. Plasma Desorption Mass Spectrometry: Coming of Age.

    ERIC Educational Resources Information Center

    Cotter, Robert J.

    1988-01-01

    Discusses the history and development of Plasma Desorption Mass Spectrometry to determine molecular weights and structures of proteins and polymers. Outlines theory, instrumentation, and sample preparation commonly used. Gives several examples of resulting spectra. (ML)

  15. Plasma Desorption Mass Spectrometry: Coming of Age.

    ERIC Educational Resources Information Center

    Cotter, Robert J.

    1988-01-01

    Discusses the history and development of Plasma Desorption Mass Spectrometry to determine molecular weights and structures of proteins and polymers. Outlines theory, instrumentation, and sample preparation commonly used. Gives several examples of resulting spectra. (ML)

  16. Protein Sequencing with Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ziady, Assem G.; Kinter, Michael

    The recent introduction of electrospray ionization techniques that are suitable for peptides and whole proteins has allowed for the design of mass spectrometric protocols that provide accurate sequence information for proteins. The advantages gained by these approaches over traditional Edman Degradation sequencing include faster analysis and femtomole, sometimes attomole, sensitivity. The ability to efficiently identify proteins has allowed investigators to conduct studies on their differential expression or modification in response to various treatments or disease states. In this chapter, we discuss the use of electrospray tandem mass spectrometry, a technique whereby protein-derived peptides are subjected to fragmentation in the gas phase, revealing sequence information for the protein. This powerful technique has been instrumental for the study of proteins and markers associated with various disorders, including heart disease, cancer, and cystic fibrosis. We use the study of protein expression in cystic fibrosis as an example.

  17. Investigation of the formation of the [2(iohexol) + Mg](2+) complex and its fragmentation in electrospray ionization tandem mass spectrometry.

    PubMed

    Guo, Mengzhe; Yin, Dengyang; Han, Jie; Li, Xiao; Zhang, Liyan; Du, Yan; Wang, Haibo; Guo, Cheng; Tang, Daoquan

    2017-01-15

    Mass spectrometry has been developed as one of the common tools for the analysis of the organometallic systems in the gas phase over decades. The study of the fragmentation of organics-metal complexes has attracted much attention since the interesting dissociation pathways exhibited by these compounds are usually different from the protonated analogues. In this work, iohexol complexed with different dications such as Mg(2)(+) , Cu(2)(+) and Zn(2)(+) have been investigated by electrospray ionization (ESI) tandem mass spectrometry. Additionally, deuterium-labeling experiments and an analogue of iohexol were utilized to confirm the reaction mechanisms. A computational chemistry method was used to identify the coordination conformation between iohexol and metal ions in the gas phase. UV detection was also used to identify the interaction between iohexol and metal ions in the liquid phase. A special gas-phase open-loop reaction of iohexol induced by Mg(2)(+) , leading to the formation of [iohexol + Mg - H - HI - C3 H4 O](+) , was observed in the collision-induced dissociation of [2(iohexol) + Mg](2+) complexes. Moreover, theoretical calculation shows the proposed coordination configuration of iohexol/Mg(2)(+) complexes. The Mg(2)(+) could have tetrahedral coordination with two iohexol molecules. The percent study is a case for better understanding the formation of a typical organic/metal complex and its gas-phase fragmentation reaction. In addition, it provides useful information for researchers working on analysis or structural elucidation of complicated compounds which contain the iohexol analogues. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Gas-Phase Structure of Amyloid-β (12 - 28) Peptide Investigated by Infrared Spectroscopy, Electron Capture Dissociation and Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Le, Thi Nga; Poully, Jean Christophe; Lecomte, Frédéric; Nieuwjaer, Nicolas; Manil, Bruno; Desfrançois, Charles; Chirot, Fabien; Lemoine, Jerome; Dugourd, Philippe; van der Rest, Guillaume; Grégoire, Gilles

    2013-12-01

    The gas-phase structures of doubly and triply protonated Amyloid-β12-28 peptides have been investigated through the combination of ion mobility (IM), electron capture dissociation (ECD) mass spectrometry, and infrared multi-photon dissociation (IRMPD) spectroscopy together with theoretical modeling. Replica-exchange molecular dynamics simulations were conducted to explore the conformational space of these protonated peptides, from which several classes of structures were found. Among the low-lying conformers, those with predicted diffusion cross-sections consistent with the ion mobility experiment were further selected and their IR spectra simulated using a hybrid quantum mechanical/semiempirical method at the ONIOM DFT/B3LYP/6-31 g(d)/AM1 level. In ECD mass spectrometry, the c/z product ion abundance (PIA) has been analyzed for the two charge states and revealed drastic differences. For the doubly protonated species, N - Cα bond cleavage occurs only on the N and C terminal parts, while a periodic distribution of PIA is clearly observed for the triply charged peptides. These PIA distributions have been rationalized by comparison with the inverse of the distances from the protonated sites to the carbonyl oxygens for the conformations suggested from IR and IM experiments. Structural assignment for the amyloid peptide is then made possible by the combination of these three experimental techniques that provide complementary information on the possible secondary structure adopted by peptides. Although globular conformations are favored for the doubly protonated peptide, incrementing the charge state leads to a conformational transition towards extended structures with 310- and α-helix motifs.

  19. Mass spectrometry in the home and garden.

    PubMed

    Pulliam, Christopher J; Bain, Ryan M; Wiley, Joshua S; Ouyang, Zheng; Cooks, R Graham

    2015-02-01

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application.

  20. Mass Spectrometry in the Home and Garden

    NASA Astrophysics Data System (ADS)

    Pulliam, Christopher J.; Bain, Ryan M.; Wiley, Joshua S.; Ouyang, Zheng; Cooks, R. Graham

    2015-02-01

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application.

  1. Challenges and developments in tandem mass spectrometry based clinical metabolomics.

    PubMed

    Ceglarek, Uta; Leichtle, Alexander; Brügel, Mathias; Kortz, Linda; Brauer, Romy; Bresler, Kristin; Thiery, Joachim; Fiedler, Georg Martin

    2009-03-25

    'Clinical metabolomics' aims at evaluating and predicting health and disease risk in an individual by investigating metabolic signatures in body fluids or tissues, which are influenced by genetics, epigenetics, environmental exposures, diet, and behaviour. Powerful analytical techniques like liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) offers a rapid, effective and economical way to analyze metabolic alterations of pre-defined target metabolites in biological samples. Novel hyphenated technical approaches like the combination of tandem mass spectrometry combined with linear ion trap (QTrap mass spectrometry) combines both identification and quantification of known and unknown metabolic targets. We describe new concepts and developments of mass spectrometry based multi-target metabolome profiling in the field of clinical diagnostics and research. Particularly, the experiences from newborn screening provided important insights about the diagnostic potential of metabolite profiling arrays and directs to the clinical aim of predictive, preventive and personalized medicine by metabolomics.

  2. Coupled Space- and Velocity-Focusing in Time-of-Flight Mass Spectrometry-a Comprehensive Theoretical Investigation.

    PubMed

    Cai, Yi-Hong; Lai, Yin-Hung; Wang, Yi-Sheng

    2015-10-01

    A comprehensive theoretical calculation that couples space- and velocity-focusing is developed for optimizing the design of a time-of-flight (TOF) mass spectrometer. Conventional designs for ion sources of TOF mass spectrometers deviate from the optimal condition because the velocity- and space-focusing conditions are considered separately for two ions with simplified equations. The result of a reexamination taking into account all essential ions reveals that the conventional ion source design, especially the length of the ion extraction region, results in poor resolving power. The comprehensive calculation demonstrates that the resolving power increases when the length of the extraction region is shorter than that of the conventional ion source. A numerical analysis indicates that the resolving power dramatically increases when the effective extraction potential compensates for the initial kinetic energy spread of ions. With typically used extraction potentials, the newly optimized ion source improves the resolving power by more than two orders of magnitude compared with the conventional design. This new theoretical interpretation can also be used to predict the optimal extraction potential and extraction delay in conventional ion sources to substantially improve the resolving power. This comprehensive calculation method is effective not only for designing new high-resolution instruments but also for optimizing commercial products.

  3. Investigation of the aroma of commercial peach (Prunus persica L. Batsch) types by Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and sensory analysis.

    PubMed

    Bianchi, Tiago; Weesepoel, Yannick; Koot, Alex; Iglesias, Ignasi; Eduardo, Iban; Gratacós-Cubarsí, Marta; Guerrero, Luis; Hortós, Maria; van Ruth, Saskia

    2017-09-01

    The aim of this study was to investigate the aroma and sensory profiles of various types of peaches (Prunus persica L. Batsch.). Forty-three commercial cultivars comprising peaches, flat peaches, nectarines, and canning peaches (pavías) were grown over two consecutive harvest years. Fruits were assessed for chemical aroma and sensory profiles. Chemical aroma profile was obtained by proton transfer reaction-mass spectrometry (PTR-MS) and spectral masses were tentatively identified with PTR-Time of Flight-MS (PTR-Tof-MS). Sensory analysis was performed at commercial maturity considering seven aroma/flavor attributes. The four types of peaches showed both distinct chemical aroma and sensory profiles. Flat peaches and canning peaches showed most distinct patterns according to discriminant analysis. The sensory data were related to the volatile compounds by partial least square regression. γ-Hexalactone, γ-octalactone, hotrienol, acetic acid and ethyl acetate correlated positively, and benzeneacetaldehyde, trimethylbenzene and acetaldehyde negatively to the intensities of aroma and ripe fruit sensory scores. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Investigation of protein-protein noncovalent interactions in soybean agglutinin by electrospray ionization time-of-flight mass spectrometry.

    PubMed

    Tang, X J; Brewer, C F; Saha, S; Chernushevich, I; Ens, W; Standing, K G

    1994-09-01

    Noncovalent interactions in soybean agglutinin (SBA) were studied on an electrospray ionization (ESI) time-of-flight mass spectrometer constructed recently at the University of Manitoba. The high m/z range and high sensitivity of the instrument together with mild ESI interface conditions turned out to be ideal for detecting this noncovalently bonded tetrameric protein (MW approximately 116,000 Da) in low charge states (z = 23 to 27). By altering the acetonitrile content of the SBA solutions it was shown that the observed SBA tetramers are due to structurally specific noncovalent associations in solution. Octamers and dodecamers (MW approximately 350,000 Da) were also detected. Information on the quaternary structure of the tetramers was obtained by analyzing the fragment-ion spectrum resulting from the collision-induced dissociation of the tetramer ions.

  5. Microbial proteomics using mass spectrometry.

    PubMed

    Hines, Harry B

    2012-01-01

    Proteomic analyses involve a series of intricate, interdependent steps involving approaches and technical issues that must be fully coordinated to obtain the optimal amount of required information about the test subject. Fortunately, many of these steps are common to most test subjects, requiring only modifications to or, in some cases, substitution of some of the steps to ensure they are relevant to the desired objective of a study. This fortunate occurrence creates an essential core of proteomic approaches and techniques that are consistently available for most studies, regardless of test subject. In this chapter, an overview of some of these core approaches, techniques, and mass spectrometric instrumentation is given, while indicating how such steps are useful for and applied to bacterial investigations. To exemplify how such proteomic concepts and techniques are applicable to bacterial investigations, a practical, quantitative method useful for bacterial proteomic analysis is presented with a discussion of possibilities, pitfalls, and some emerging technology to provide a compilation of information from the diverse literature that is intermingled with experimental experience.

  6. Top-Down Mass Spectrometry: Proteomics to Proteoforms.

    PubMed

    Patrie, Steven M

    2016-01-01

    This chapter highlights many of the fundamental concepts and technologies in the field of top-down mass spectrometry (TDMS), and provides numerous examples of contributions that TD is making in biology, biophysics, and clinical investigations. TD workflows include variegated steps that may include non-specific or targeted preparative strategies, orthogonal liquid chromatography techniques, analyte ionization, mass analysis, tandem mass spectrometry (MS/MS) and informatics procedures. This diversity of experimental designs has evolved to manage the large dynamic range of protein expression and diverse physiochemical properties of proteins in proteome investigations, tackle proteoform microheterogeneity, as well as determine structure and composition of gas-phase proteins and protein assemblies.

  7. Glossary of terms for separations coupled to mass spectrometry.

    PubMed

    Murray, Kermit K

    2010-06-18

    This document is a glossary of terms for separations coupled to mass spectrometry. It covers gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry, and supercritical fluid chromatography/mass spectrometry and the sample introduction, ionization, and data analysis methods used with these combined techniques. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  8. Mass spectrometry: a revolution in clinical microbiology?

    PubMed

    Lavigne, Jean-Philippe; Espinal, Paula; Dunyach-Remy, Catherine; Messad, Nourredine; Pantel, Alix; Sotto, Albert

    2013-02-01

    Recently, different bacteriological laboratory interventions that decrease reporting time have been developed. These promising new broad-based techniques have merit, based on their ability to identify rapidly many bacteria, organisms difficult to grow or newly emerging strains, as well as their capacity to track disease transmission. The benefit of rapid reporting of identification and/or resistance of bacteria can greatly impact patient outcomes, with an improvement in the use of antibiotics, in the reduction of the emergence of multidrug resistant bacteria and in mortality rates. Different techniques revolve around mass spectrometry (MS) technology: matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), PCR combined with electrospray ionization-mass spectrometry (PCR/ESIMS), iPLEX MassArray system and other new evolutions combining different techniques. This report emphasizes the (r)evolution of these technologies in clinical microbiology.

  9. Mass Spectrometry of Intact Membrane Protein Complexes

    PubMed Central

    Laganowsky, Arthur; Reading, Eamonn; Hopper, Jonathan T.S.; Robinson, Carol V.

    2014-01-01

    Mass spectrometry of intact soluble protein complexes has emerged as a powerful technique to study the stoichiometry, structure-function and dynamics of protein assemblies. Recent developments have extended this technique to the study of membrane protein complexes where it has already revealed subunit stoichiometries and specific phospholipid interactions. Here, we describe a protocol for mass spectrometry of membrane protein complexes. The protocol begins with preparation of the membrane protein complex enabling not only the direct assessment of stoichiometry, delipidation, and quality of the target complex, but also evaluation of the purification strategy. A detailed list of compatible non-ionic detergents is included, along with a protocol for screening detergents to find an optimal one for mass spectrometry, biochemical and structural studies. This protocol also covers the preparation of lipids for protein-lipid binding studies and includes detailed settings for a Q-ToF mass spectrometer after introduction of complexes from gold-coated nanoflow capillaries. PMID:23471109

  10. Analytical aspects of hydrogen exchange mass spectrometry

    PubMed Central

    Engen, John R.; Wales, Thomas E.

    2016-01-01

    The analytical aspects of measuring hydrogen exchange by mass spectrometry are reviewed. The nature of analytical selectivity in hydrogen exchange is described followed by review of the analytical tools required to accomplish fragmentation, separation, and the mass spectrometry measurements under restrictive exchange quench conditions. In contrast to analytical quantitation that relies on measurements of peak intensity or area, quantitation in hydrogen exchange mass spectrometry depends on measuring a mass change with respect to an undeuterated or deuterated control, resulting in a value between zero and the maximum amount of deuterium that could be incorporated. Reliable quantitation is a function of experimental fidelity and to achieve high measurement reproducibility, a large number of experimental variables must be controlled during sample preparation and analysis. The method also reports on important qualitative aspects of the sample, including conformational heterogeneity and population dynamics. PMID:26048552

  11. Mass Spectrometry: A Technique of Many Faces

    PubMed Central

    Olshina, Maya A.; Sharon, Michal

    2016-01-01

    Protein complexes form the critical foundation for a wide range of biological process, however understanding the intricate details of their activities is often challenging. In this review we describe how mass spectrometry plays a key role in the analysis of protein assemblies and the cellular pathways which they are involved in. Specifically, we discuss how the versatility of mass spectrometric approaches provides unprecedented information on multiple levels. We demonstrate this on the ubiquitin-proteasome proteolytic pathway, a process that is responsible for protein turnover. We follow the various steps of this degradation route and illustrate the different mass spectrometry workflows that were applied for elucidating molecular information. Overall, this review aims to stimulate the integrated use of multiple mass spectrometry approaches for analyzing complex biological systems. PMID:28100928

  12. Investigation of cannabis biomarkers and transformation products in waters by liquid chromatography coupled to time of flight and triple quadrupole mass spectrometry.

    PubMed

    Boix, Clara; Ibáñez, María; Bijlsma, Lubertus; Sancho, Juan V; Hernández, Félix

    2014-03-01

    11-Nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH) is commonly selected as biomarker for the investigation of cannabis consumption through wastewater analysis. The removal efficiency of THC-COOH in wastewater treatment plants (WWTPs) has been reported to vary between 31% and 98%. Accordingly, possible transformation products (TPs) of this metabolite might be formed during treatment processes or in receiving surface water under environmental conditions. In this work, surface water was spiked with THC-COOH and subjected to hydrolysis, chlorination and photo-degradation (both ultraviolet and simulated sunlight) experiments under laboratory-controlled conditions. One hydrolysis, eight chlorination, three ultraviolet photo-degradation and seven sunlight photo-degradation TPs were tentatively identified by liquid chromatography coupled to quadrupole time-of-flight mass spectrometer (LC-QTOF MS). In a subsequent step, THC-COOH and the identified TPs were searched in wastewater samples using LC coupled to tandem mass spectrometry (LC-MS/MS) with triple quadrupole. THC-COOH was found in all influent and effluent wastewater samples analyzed, although at significant lower concentrations in the effluent samples. The removal efficiency of WWTP under study was approximately 86%. Furthermore, THC-COOH was also investigated in several surface waters, and it was detected in 50% of the samples analyzed. Regarding TPs, none were found in influent wastewater, while one hydrolysis and five photo-degradation (simulated sunlight) TPs were detected in effluent and surface waters. The most detected compound, resulting from sunlight photo-degradation, was found in 60% of surface waters analyzed. This fact illustrates the importance of investigating these TPs in the aquatic environment.

  13. Quantitative imaging of platinum based on laser ablation-inductively coupled plasma-mass spectrometry to investigate toxic side effects of cisplatin.

    PubMed

    Köppen, C; Reifschneider, O; Castanheira, I; Sperling, M; Karst, U; Ciarimboli, G

    2015-12-01

    This work presents a quantitative bioimaging method for platinum based on laser ablation-inductively coupled plasma-mass spectrometry and its application for a biomedical study concerning toxic side effects of cisplatin. To trace the histopathology back to cisplatin, platinum was localized and quantified in major functional units of testicle, cochlea, kidney, nerve and brain sections from cisplatin treated mice. The direct consideration of the histology enables precise interpretation of the Pt images and the novel quantitative evaluation approach allows significantly more precise investigations than the pure image. For the first time, platinum was detected and quantified in all major injured structures including organ of Corti of cochlea and seminiferous tubule of testicle. In this way, proximal tubule in kidney, Leydig cells in testicle, stria vascularis and organ of Corti in cochlea and nerve fibers in sciatic nerves are confirmed as targets of cisplatin in these organs. However, the accumulation of platinum in almost all investigated structures also raises questions about more complex pathogenesis including direct and indirect interruption of several biological processes.

  14. Investigation of endogenous blood lipids components that contribute to matrix effects in dried blood spot samples by liquid chromatography-tandem mass spectrometry.

    PubMed

    Ismaiel, Omnia A; Jenkins, Rand G; Karnes, H Thomas

    2013-08-01

    Dried blood spot (DBS) sampling coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a rapidly developing approach in the field of biopharmaceutical analysis. DBS sampling enables analysis of small sample volumes with high sensitivity and selectivity while providing a convenient easy to store and ship format. Lipid components that may be extracted during biological sample processing may result in matrix ionization effects and can significantly affect the precision and accuracy of the results. Glycerophosphocholines (GPChos), cholesterols and triacylglycerols (TAG) are the main lipid components that contribute to matrix effects in LC-MS/MS. Various organic solvents such as methanol, acetonitrile, methyl tertiary butyl ether, ethyl ether, dichloromethane and n-hexane were investigated for elution of these lipid components from DBS samples. Methanol extracts demonstrated the highest levels of GPChos whereas ethyl ether and n-hexane extracts contained less than 1.0 % of the GPChos levels in the methanol extracts. Ethyl ether extracts contained the highest levels of cholesterols and TAG in comparison to other investigated organic solvents. Acetonitrile is recommended as an elution solvent due to low lipid recoveries. Matrix effects resulted from different extracted lipid components should be studied and assessed carefully in DBS samples. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Investigation by mass spectrometry of metal complexes of new molecular hosts: cyclic oligomer of sugar amino acid and sugar-aza-crown ethers.

    PubMed

    Fournier, Françoise; Afonso, Carlos; Ménand, Mickaël; Hamon, Louis; Xie, Juan; Tabet, Jean-Claude

    2008-01-01

    The affinity of cyclic oligomers of sugar amino acid and sugar-aza-crown ether compounds towards various transition metal cations (Cu(II), Ni(II), Co(II), Fe(II) and Zn(II)) was investigated with positive-ion electrospray mass spectrometry. The binding between the receptors (M) and the different metals (Met) is evidenced mainly by the presence of the [M + Met(II)Cl](+) ion. The experimental results showed that all studied receptors present specificity to Cu(II). An attempt has been made with CuI but no complexation was obtained. The formation of these complexes can be rationalized by considering the presence of two oxygens and two nitrogens on the receptor rim. The lone electron pair can serve as the electron donor to Cu(II). Theoretical calculations were carried out in order to show the structure of the complex and, in particular, to determine if Cu(2+) is situated either on the outer surface, on the rim of the receptor or inside the cavity. Comparison of complex formation was carried out by mixing the four receptors with various amounts of Cu(II) (one equivalent and five equivalents). It appears that the best complexation was obtained with the sugar-aza-crown ethers (amine linker) for both benzylated and methylated compounds. In addition, the stereochemical effects have been investigated.

  16. Spatially resolved investigation of systemic and contact pesticides in plant material by desorption electrospray ionization mass spectrometry imaging (DESI-MSI).

    PubMed

    Gerbig, Stefanie; Brunn, Hubertus E; Spengler, Bernhard; Schulz, Sabine

    2015-09-01

    Distribution of pesticides both on the surface of leaves and in cross sections of plant stem and leaves was investigated using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with a spatial resolution of 50-100 μm. Two commercially available insecticide sprays containing different contact pesticides were applied onto leaves of Cotoneaster horizontalis, and the distributions of all active ingredients were directly analyzed. The first spray contained pyrethrins and rapeseed oil, both known as natural insecticides. Each component showed an inhomogeneous spreading throughout the leaf, based on substance polarity and solubility. The second spray contained the synthetic insecticides imidacloprid and methiocarb. Imidacloprid accumulated on the border of the leaf, while methiocarb was distributed more homogenously. In order to investigate the incorporation of a systemically acting pesticide into Kalanchoe blossfeldiana, a commercially available insecticide tablet containing dimethoate was spiked to the soil of the plant. Cross sections of the stem and leaf were obtained 25 and 60 days after application. Dimethoate was mainly detected in the transport system of the plant after 25 days, while it was found to be homogenously distributed in a leaf section after 60 days.

  17. Detection of gunshot residues using mass spectrometry.

    PubMed

    Taudte, Regina Verena; Beavis, Alison; Blanes, Lucas; Cole, Nerida; Doble, Philip; Roux, Claude

    2014-01-01

    In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR), although the "gold standard" for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX). This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis.

  18. Mass Spectrometry Methodology in Lipid Analysis

    PubMed Central

    Li, Lin; Han, Juanjuan; Wang, Zhenpeng; Liu, Jian’an; Wei, Jinchao; Xiong, Shaoxiang; Zhao, Zhenwen

    2014-01-01

    Lipidomics is an emerging field, where the structures, functions and dynamic changes of lipids in cells, tissues or body fluids are investigated. Due to the vital roles of lipids in human physiological and pathological processes, lipidomics is attracting more and more attentions. However, because of the diversity and complexity of lipids, lipid analysis is still full of challenges. The recent development of methods for lipid extraction and analysis and the combination with bioinformatics technology greatly push forward the study of lipidomics. Among them, mass spectrometry (MS) is the most important technology for lipid analysis. In this review, the methodology based on MS for lipid analysis was introduced. It is believed that along with the rapid development of MS and its further applications to lipid analysis, more functional lipids will be identified as biomarkers and therapeutic targets and for the study of the mechanisms of disease. PMID:24921707

  19. Mass Spectrometry Imaging in Oncology Drug Discovery.

    PubMed

    Goodwin, R J A; Bunch, J; McGinnity, D F

    2017-01-01

    Over the last decade mass spectrometry imaging (MSI) has been integrated in to many areas of drug discovery and development. It can have significant impact in oncology drug discovery as it allows efficacy and safety of compounds to be assessed against the backdrop of the complex tumour microenvironment. We will discuss the roles of MSI in investigating compound and metabolite biodistribution and defining pharmacokinetic -pharmacodynamic relationships, analysis that is applicable to all drug discovery projects. We will then look more specifically at how MSI can be used to understand tumour metabolism and other applications specific to oncology research. This will all be described alongside the challenges of applying MSI to industry research with increased use of metrology for MSI. © 2017 Elsevier Inc. All rights reserved.

  20. Mass spectrometry methodology in lipid analysis.

    PubMed

    Li, Lin; Han, Juanjuan; Wang, Zhenpeng; Liu, Jian'an; Wei, Jinchao; Xiong, Shaoxiang; Zhao, Zhenwen

    2014-06-11

    Lipidomics is an emerging field, where the structures, functions and dynamic changes of lipids in cells, tissues or body fluids are investigated. Due to the vital roles of lipids in human physiological and pathological processes, lipidomics is attracting more and more attentions. However, because of the diversity and complexity of lipids, lipid analysis is still full of challenges. The recent development of methods for lipid extraction and analysis and the combination with bioinformatics technology greatly push forward the study of lipidomics. Among them, mass spectrometry (MS) is the most important technology for lipid analysis. In this review, the methodology based on MS for lipid analysis was introduced. It is believed that along with the rapid development of MS and its further applications to lipid analysis, more functional lipids will be identified as biomarkers and therapeutic targets and for the study of the mechanisms of disease.

  1. Liquid chromatography-mass spectrometry (LC-MS) investigation of the thiobarbituric acid reactive substances (TBARS) reaction.

    PubMed

    Jardine, Daniel; Antolovich, Michael; Prenzler, Paul D; Robards, Kevin

    2002-03-13

    The thiobarbituric acid reactive substances (TBARS) assay is a commonly used method for the detection of lipid peroxidation. Malondialdehyde is formed as a result of lipid peroxidation and reacts with thiobarbituric acid to form a pink pigment that has an absorption maximum at 532 nm. Other compounds also react with thiobarbituric acid to form colored species that can interfere with this assay, but little is known about these interfering species. This is the first investigation using LC-MS and MS-MS to study the structures of the pink adduct as well as a common unstable yellow interference compound, which absorbs at 455 nm. Also, the presence of barbituric acid impurities in the thiobarbituric acid reagent was found to produce 1:1:1 thiobarbituric acid/malondialdehyde/barbituric acid and 2:1 barbituric acid/malondialdehyde adducts that absorbed at 513 and 490 nm, respectively, indicating that thiobarbituric acid should be purified before use.

  2. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  3. Biodegradation of carbamazepine and clarithromycin by Trichoderma harzianum and Pleurotus ostreatus investigated by liquid chromatography - high-resolution tandem mass spectrometry (FTICR MS-IRMPD).

    PubMed

    Buchicchio, Alessandro; Bianco, Giuliana; Sofo, Adriano; Masi, Salvatore; Caniani, Donatella

    2016-07-01

    In this study, the capability of pharmaceutical biodegradation of fungus Trichoderma harzianum was evaluated through the comparison with the well-known biodegradation capability of white-rot fungus Pleurotus ostreatus. The study was performed in aqueous phase under aerobic conditions, using two of the most frequently detected drugs in water bodies: carbamazepine and clarithromycin, with concentrations commonly found in treated wastewater (4μg/l and 0.03μg/l respectively). For the first time, we demonstrated that T. harzianum is able to remove carbamazepine and clarithromycin. The analyses were performed by reversed-phase liquid chromatography/mass spectrometry, using high-resolution Fourier-transform ion cyclotron resonance mass spectrometry upon electrospray ionization in positive ion mode. The high selectivity and mass accuracy provided by high-resolution mass spectrometry, allowed us to identify some unknown metabolites. On the basis of our study, the major metabolites detected in liquid culture treated by T. harzianum were: 14-hydroxy-descladinosyl- and descladinosyl-clarithromycin, which are pharmacologically inactive products not dangerous for the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Mass spectrometry imaging and profiling of single cells

    PubMed Central

    Lanni, Eric J.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2012-01-01

    Mass spectrometry imaging and profiling of individual cells and subcellular structures provide unique analytical capabilities for biological and biomedical research, including determination of the biochemical heterogeneity of cellular populations and intracellular localization of pharmaceuticals. Two mass spectrometry technologies—secondary ion mass spectrometry (SIMS) and matrix assisted laser desorption ionization mass spectrometry (MALDI MS)—are most often used in micro-bioanalytical investigations. Recent advances in ion probe technologies have increased the dynamic range and sensitivity of analyte detection by SIMS, allowing two- and three-dimensional localization of analytes in a variety of cells. SIMS operating in the mass spectrometry imaging (MSI) mode can routinely reach spatial resolutions at the submicron level; therefore, it is frequently used in studies of the chemical composition of subcellular structures. MALDI MS offers a large mass range and high sensitivity of analyte detection. It has been successfully applied in a variety of single-cell and organelle profiling studies. Innovative instrumentation such as scanning microprobe MALDI and mass microscope spectrometers enable new subcellular MSI measurements. Other approaches for MS-based chemical imaging and profiling include those based on near-field laser ablation and inductively-coupled plasma MS analysis, which offer complementary capabilities for subcellular chemical imaging and profiling. PMID:22498881

  5. Analysis of omnoponum by surface-ionization mass spectrometry and liquid chromatography tandem mass spectrometry methods.

    PubMed

    Usmanov, Dilshadbek; Khasanov, Usman; Pantsirev, Aleksey; Van Bocxlaer, Jan

    2010-12-01

    This paper provides the development of analytical capabilities of surface-ionization mass spectrometry (SI/MS) and high performance liquid chromatography with tandem mass spectrometry (HPLC/MS/MS) for narcotic analgesic omnoponum, which perfectly exemplifies a mixture of opium alkaloids. It has been revealed that the investigated opiates solution, omnoponum, is ionized by the surface ionization (SI) method with high sensitivity. In the SI mass spectrum, M+, (M-H)+, (M-H-2nH)+, (M-R)+ and (M-R-2nH)+ ion lines, where M is a molecule, H is the hydrogen atom and R is a radical, were observed. These ion lines consist of combined omnoponum mixture SI mass spectra, i.e. morphine, codeine, thebaine, papaverine, and narcotine. Moreover, while the study of omnoponum by HPLC/MS/MS methods has attested that the mixture really consists of 5 components, it has been demonstrated that the SI/MS method can be utilized for the analysis of this mixture without the necessity of its chromatographic separation. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  6. Investigation of the Chemical Interface in the Soybean-Aphid and Rice-Bacteria Interactions Using MALDI-Mass Spectrometry Imaging.

    PubMed

    Klein, Adam T; Yagnik, Gargey B; Hohenstein, Jessica D; Ji, Zhiyuan; Zi, Jiachen; Reichert, Malinda D; MacIntosh, Gustavo C; Yang, Bing; Peters, Reuben J; Vela, Javier; Lee, Young Jin

    2015-05-19

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plant-pest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between rice-bacterium and soybean-aphid were investigated as two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plant-pest interactions. Specifically, salicylic acid and isoflavone based resistance was visualized in the soybean-aphid system and antibiotic diterpenoids in rice-bacterium interactions.

  7. Investigation of the chemical interface in the soybean–aphid and rice–bacteria interactions using MALDI-mass spectrometry imaging

    SciTech Connect

    Klein, Adam T.; Yagnik, Gargey B.; Hohenstein, Jessica D.; Ji, Zhiyuan; Zi, Jiachen; Reichert, Malinda D.; MacIntosh, Gustavo C.; Yang, Bing; Peters, Reuben J.; Vela, Javier; Lee, Young Jin

    2015-04-27

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plant–pest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between rice–bacterium and soybean–aphid were investigated as two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plant–pest interactions. Basically, salicylic acid and isoflavone based resistance was visualized in the soybean–aphid system and antibiotic diterpenoids in rice–bacterium interactions.

  8. Investigation of the chemical interface in the soybean–aphid and rice–bacteria interactions using MALDI-mass spectrometry imaging

    DOE PAGES

    Klein, Adam T.; Yagnik, Gargey B.; Hohenstein, Jessica D.; ...

    2015-04-27

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plant–pest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between rice–bacterium and soybean–aphid were investigated asmore » two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plant–pest interactions. Basically, salicylic acid and isoflavone based resistance was visualized in the soybean–aphid system and antibiotic diterpenoids in rice–bacterium interactions.« less

  9. Investigation of dyeing behavior of oxidative dye in fine structures of the human hair cuticle by nanoscale secondary ion mass spectrometry.

    PubMed

    Kojima, T; Yamada, H; Saito, Y; Nawa, T; Isobe, M; Yamamoto, T; Aoki, D; Matsushita, Y; Fukushima, K

    2015-08-01

    In oxidative coloring, the hair cuticle layers are not only the penetration pathway for active ingredients but also one of the most important dyeing regions. The dyeing mechanism of oxidative dyes in fine structures of the cuticle remains unclear. To investigate the dyeing behavior of oxidative dyes in fine structures of the cuticle, hair cross-sections were analyzed by nanoscale secondary ion mass spectrometry (NanoSIMS). The preparation method of hair cross-section for NanoSIMS measurement was improved. Improved hair cross-sections were analyzed using NanoSIMS. The cuticle layer thickness of the hair cross-section could be widened. It was confirmed that (12) C(-) ions were more strongly detected from endocuticle than from other fine structures of cuticle. The NanoSIMS (12) C(-) image and hue saturation intensity (HSI) D(-) /(1) H(-) ratio image of the hair, dyed with deuterium-labeled oxidative dye, indicated that the endocuticle had a higher D(-) /(1) H(-) ratio than the other fine structures of the cuticle. It was substantiated that more colored chromophores were fixated in the endocuticle than in other fine structures of the cuticle. The dyeing behavior of oxidative dyes in fine structures of hair cuticle was substantiated by NanoSIMS analysis using the improved hair cross-section preparation method. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Processing technology investigation of loquat (Eriobotrya japonica) leaf by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with chemometrics.

    PubMed

    Wu, Labin; Jiang, Xue; Huang, Linfang; Chen, Shilin

    2013-01-01

    Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and multivariate statistical analysis were used to investigate the processing technology of Loquat (Eriobotrya japonica) leaf (pipaye, PPY). The differences in samples processed using different methods were revealed by unsupervised principal component analysis (PCA). In the scores plot of PCA, honey-processed PPY (PPPY), crude PPY (CPPY), and heated PPY (HPPY) were clearly discriminated. Furthermore, samples processed at different temperatures could also be distinguished; indeed, our PCA results demonstrated the importance of temperature during processing. Two unique marker ions were found to discriminate between PPPY and CPPY by orthogonal partial least squares discriminant analysis (OPLS-DA), which could be used as potential chemical markers. The method was further confirmed by a verification test with commercial PPY. The orthogonal array experiment revealed an optimized processing condition with 50% honey at 140°C for 20 min after 4 h of moistening time, a process that provides significant information for standardized production.

  11. Processing Technology Investigation of Loquat (Eriobotrya japonica) Leaf by Ultra-Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry Combined with Chemometrics

    PubMed Central

    Wu, Labin; Jiang, Xue; Huang, Linfang; Chen, Shilin

    2013-01-01

    Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and multivariate statistical analysis were used to investigate the processing technology of Loquat (Eriobotrya japonica) leaf (pipaye, PPY). The differences in samples processed using different methods were revealed by unsupervised principal component analysis (PCA). In the scores plot of PCA, honey-processed PPY (PPPY), crude PPY (CPPY), and heated PPY (HPPY) were clearly discriminated. Furthermore, samples processed at different temperatures could also be distinguished; indeed, our PCA results demonstrated the importance of temperature during processing. Two unique marker ions were found to discriminate between PPPY and CPPY by orthogonal partial least squares discriminant analysis (OPLS-DA), which could be used as potential chemical markers. The method was further confirmed by a verification test with commercial PPY. The orthogonal array experiment revealed an optimized processing condition with 50% honey at 140°C for 20 min after 4 h of moistening time, a process that provides significant information for standardized production. PMID:23667702

  12. An investigation of the antidepressant action of xiaoyaosan in rats using ultra performance liquid chromatography-mass spectrometry combined with metabonomics.

    PubMed

    Gao, Xiao-Xia; Cui, Jie; Zheng, Xing-Yu; Li, Zhen-Yu; Choi, Young-Hae; Zhou, Yu-Zhi; Tian, Jun-Sheng; Xing, Jie; Tan, Xiao-Jie; Du, Guan-Hua; Qin, Xue-Mei

    2013-07-01

    A rapid, highly sensitive, and selective method was applied in a non-invasive way to investigate the antidepressant action of Xiaoyaosan (XYS) using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) and chemometrics. Many significantly altered metabolites were used to explain the mechanism. Venlafaxine HCl and fluoxetine HCl were used as chemical positive control drugs with a relatively clear mechanism of action to evaluate the efficiency and to predict the mechanism of action of XYS. Urine obtained from rats subjected to chronic unpredictable mild stress (CUMS) was analyzed by UPLC-MS. Distinct changes in the pattern of metabolites in the rat urine after CUMS production and drug intervention were observed using partial least squares-discriminant analysis. The results of behavioral tests and multivariate analysis showed that CUMS was successfully reproduced, and a moderate-dose XYS produced significant therapeutic effects in the rodent model, equivalent to those of the positive control drugs, venlafaxine HCl and fluoxetine HCl. Metabolites with significant changes induced by CUMS were identified, and 17 biomarker candidates for stress and drug intervention were identified. The therapeutic effect of XYS on depression may involve regulation of the dysfunctions of energy metabolism, amino acid metabolism, and gut microflora changes. Metabonomic methods are valuable tools for measuring efficacy and mechanisms of action in the study of traditional Chinese medicines. Copyright © 2012 John Wiley & Sons, Ltd.

  13. The power of energy-resolved tandem mass spectrometry experiments for resolution of isomers: the case of drug plasma stability investigation of multidrug resistance inhibitors.

    PubMed

    Menicatti, Marta; Guandalini, Luca; Dei, Silvia; Floriddia, Elisa; Teodori, Elisabetta; Traldi, Pietro; Bartolucci, Gianluca

    2016-02-15

    A series of drug plasma stability experiments were carried out to evaluate the bioavailability of three multidrug resistance inhibitors. The studied compounds are positional isomers; therefore, a chromatographic separation or taking advantage of specific collisionally activated decomposition pathways, obtained by tandem mass spectrometry (MS/MS) experiments, is necessary in order to resolve them. A method was developed for quantitative determination of the analytes in plasma using liquid chromatography (LC) coupled with a triple quadrupole mass spectrometer operating in MS/MS mode. Different collisional approaches were employed based on the potentiality of a triple quadrupole system. Aside from the classical product ion spectroscopy, energy-resolved MS/MS experiments and a post-processing mathematical algorithm tool (LEDA) were used to distinguish among different kinds of inhibitors present in the sample batch. The developed LC/MS/MS method showed precision between 1.8-7.9%, accuracy ranging from 92.8 to 99.9% and limit of detection (LOD) values in the range 1.0-1.4 ng mL(-1) for all the analytes. The evaluation of matrix effects demonstrated that the sample preparation procedure did not affect the ionization efficiency or recovery (matrix effects and recovery larger than 88%). Finally, the LEDA tool was able to differentiate among the isomers, ensuring their proper monitoring. The proposed LC/MS/MS method was suitable for evaluating the stability of the analytes in plasma samples, although small concentration variations occurred. Furthermore, the investigation on the energetics of fragmentation pathways allowed the better product ions and optimal abundance ratios to be selected for LEDA application into a multi-component analysis. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  14. Fast Atom Bombardment Mass Spectrometry.

    ERIC Educational Resources Information Center

    Rinehart, Kenneth L., Jr.

    1982-01-01

    Discusses reactions and characteristics of fast atom bombardment (FAB) mass spectroscopy in which samples are ionized in a condensed state by bombardment with xenon or argon atoms, yielding positive/negative secondary ions. Includes applications of FAB to structural problems and considers future developments using the technique. (Author/JN)

  15. Fast Atom Bombardment Mass Spectrometry.

    ERIC Educational Resources Information Center

    Rinehart, Kenneth L., Jr.

    1982-01-01

    Discusses reactions and characteristics of fast atom bombardment (FAB) mass spectroscopy in which samples are ionized in a condensed state by bombardment with xenon or argon atoms, yielding positive/negative secondary ions. Includes applications of FAB to structural problems and considers future developments using the technique. (Author/JN)

  16. Fourier transform ion cyclotron resonance mass spectrometry

    NASA Astrophysics Data System (ADS)

    Marshall, Alan G.

    1998-06-01

    As for Fourier transform infrared (FT-IR) interferometry and nuclear magnetic resonance (NMR) spectroscopy, the introduction of pulsed Fourier transform techniques revolutionized ion cyclotron resonance mass spectrometry: increased speed (factor of 10,000), increased sensitivity (factor of 100), increased mass resolution (factor of 10,000-an improvement not shared by the introduction of FT techniques to IR or NMR spectroscopy), increased mass range (factor of 500), and automated operation. FT-ICR mass spectrometry is the most versatile technique for unscrambling and quantifying ion-molecule reaction kinetics and equilibria in the absence of solvent (i.e., the gas phase). In addition, FT-ICR MS has the following analytically important features: speed (~1 second per spectrum); ultrahigh mass resolution and ultrahigh mass accuracy for analysis of mixtures and polymers; attomole sensitivity; MSn with one spectrometer, including two-dimensional FT/FT-ICR/MS; positive and/or negative ions; multiple ion sources (especially MALDI and electrospray); biomolecular molecular weight and sequencing; LC/MS; and single-molecule detection up to 108 Dalton. Here, some basic features and recent developments of FT-ICR mass spectrometry are reviewed, with applications ranging from crude oil to molecular biology.

  17. A history of mass spectrometry in Australia.

    PubMed

    Downard, Kevin M; de Laeter, John R

    2005-09-01

    An interest in mass spectrometry in Australia can be traced back to the 1920s with an early correspondence with Francis Aston who first visited these shores a decade earlier. The region has a rich tradition in both the development of the field and its application, from early measurements of ionization and appearance potentials by Jim Morrison at the Council for Scientific and Industrial Research (CSIR) around 1950 to the design and construction of instrumentation including the first use of a triple quadrupole mass spectrometer for tandem mass spectrometry, the first suite of programs to simulate ion optics (SIMION), the development of early TOF/TOF instruments and orthogonal acceleration and the local design and construction of several generations of a sensitive high-resolution ion microprobe (SHRIMP) instrument. Mass spectrometry has been exploited in the study and characterization of the constituents of this nation's unique flora and fauna from Australian apples, honey, tea plant and eucalyptus oil, snake, spider, fish and frog venoms, coal, oil, sediments and shale, environmental studies of groundwater to geochronological dating of limestone and granite, other terrestrial and meteoritic rocks and coral from the Great Barrier Reef. Peter Jeffery's establishment of geochronological dating techniques in Western Australia in the early 1950s led to the establishment of geochronology research both at the Australian National University and at what is now the Curtin Institute of Technology in the 1960s. This article traces the history of mass spectrometry in its many guises and applications in the island continent of Australia. An article such as this can never be complete. It instead focuses on contributions of scientists who played a major role in the early establishment of mass spectrometry in Australia. In general, those who are presently active in the field, and whose histories are incomplete, have been mentioned at best only briefly despite their important

  18. Targeted Quantitation of Proteins by Mass Spectrometry

    PubMed Central

    2013-01-01

    Quantitative measurement of proteins is one of the most fundamental analytical tasks in a biochemistry laboratory, but widely used immunochemical methods often have limited specificity and high measurement variation. In this review, we discuss applications of multiple-reaction monitoring (MRM) mass spectrometry, which allows sensitive, precise quantitative analyses of peptides and the proteins from which they are derived. Systematic development of MRM assays is permitted by databases of peptide mass spectra and sequences, software tools for analysis design and data analysis, and rapid evolution of tandem mass spectrometer technology. Key advantages of MRM assays are the ability to target specific peptide sequences, including variants and modified forms, and the capacity for multiplexing that allows analysis of dozens to hundreds of peptides. Different quantitative standardization methods provide options that balance precision, sensitivity, and assay cost. Targeted protein quantitation by MRM and related mass spectrometry methods can advance biochemistry by transforming approaches to protein measurement. PMID:23517332

  19. Absorption mode FTICR mass spectrometry imaging.

    PubMed

    Smith, Donald F; Kilgour, David P A; Konijnenburg, Marco; O'Connor, Peter B; Heeren, Ron M A

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here, we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image, and then, these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode "Datacubes" for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  20. Laser desorption mass spectrometry for molecular diagnosis

    NASA Astrophysics Data System (ADS)

    Chen, C. H. Winston; Taranenko, N. I.; Zhu, Y. F.; Allman, S. L.; Tang, K.; Matteson, K. J.; Chang, L. Y.; Chung, C. N.; Martin, Steve; Haff, Lawrence

    1996-04-01

    Laser desorption mass spectrometry has been used for molecular diagnosis of cystic fibrosis. Both 3-base deletion and single-base point mutation have been successfully detected by clinical samples. This new detection method can possibly speed up the diagnosis by one order of magnitude in the future. It may become a new biotechnology technique for population screening of genetic disease.

  1. Pyrolysis Mass Spectrometry of Complex Organic Materials.

    ERIC Educational Resources Information Center

    Meuzelaar, Henk L. C.; And Others

    1984-01-01

    Illustrates the state of the art in pyrolysis mass spectrometry techniques through applications in: (1) structural determination and quality control of synthetic polymers; (2) quantitative analysis of polymer mixtures; (3) classification and structural characterization of fossil organic matter; and (4) nonsupervised numerical extraction of…

  2. Pyrolysis Mass Spectrometry of Complex Organic Materials.

    ERIC Educational Resources Information Center

    Meuzelaar, Henk L. C.; And Others

    1984-01-01

    Illustrates the state of the art in pyrolysis mass spectrometry techniques through applications in: (1) structural determination and quality control of synthetic polymers; (2) quantitative analysis of polymer mixtures; (3) classification and structural characterization of fossil organic matter; and (4) nonsupervised numerical extraction of…

  3. Nanostructure-initiator mass spectrometry biometrics

    DOEpatents

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  4. Optimization Of A Mass Spectrometry Process

    SciTech Connect

    Lopes, Jose; Alegria, F. Correa; Redondo, Luis; Barradas, N. P.; Alves, E.; Rocha, Jorge

    2011-06-01

    In this paper we present and discuss a system developed in order to optimize the mass spectrometry process of an ion implanter. The system uses a PC to control and display the mass spectrum. The operator interacts with the I/O board, that interfaces with the computer and the ion implanter by a LabVIEW code. Experimental results are shown and the capabilities of the system are discussed.

  5. Ambient air particle transport into the effluent of a cold atmospheric-pressure argon plasma jet investigated by molecular beam mass spectrometry

    NASA Astrophysics Data System (ADS)

    Dünnbier, M.; Schmidt-Bleker, A.; Winter, J.; Wolfram, M.; Hippler, R.; Weltmann, K.-D.; Reuter, S.

    2013-10-01

    Ambient air species, which are transported into the active effluent of an atmospheric-pressure plasma jet result in highly reactive oxygen and nitrogen species (RONS). Especially for the envisaged application field of plasma medicine, these RONS are responsible for strong biological responses. In this work, the effect of ambient air transport into the effluent of an atmospheric-pressure plasma argon jet on the on-axis densities of nitrogen, oxygen and argon was investigated by means of absolutely calibrated molecular beam mass spectrometry (MBMS). According to biomedical experiments a (bottomless) Petri dish was installed in front of the MBMS. In the following, the near flow field is referring to the region close to the nozzle exit and the far flow field is referring to the region beyond that. The absolute on-axis densities were obtained by three different methods, for the near flow field with VUV-absorption technique, for the far flow field with the MBMS and the total flow field was calculated with a computational fluid dynamics (CFD) simulation. The results of the ambient air particle densities of all independent methods were compared and showed an excellent agreement. Therefore the transport processes of ambient air species can be measured for the whole effluent of an atmospheric-pressure plasma jet. Additionally, with the validation of the simulation it is possible in future to calculate the ambient species transport for various gas fluxes in the same turbulent flow regime. Comparing the on-axis densities obtained with an ignited and with a non-ignited plasma jet shows that for the investigated parameters, the main influence on the ambient air species transport is due to the increased temperature in the case when the jet is switched on. Moreover, the presence of positive ions (e.g. ArN_{2}^{+} ) formed due to the interaction of plasma-produced particles and ambient air species, which are transported into the effluent, is shown.

  6. Investigation of the new sorption preconcentration systems for determination of noble metals in rocks by inductively coupled plasma-mass spectrometry.

    PubMed

    Dubenskiy, A S; Seregina, I F; Blinnikova, Z K; Tsyurupa, M P; Pavlova, L A; Davankov, V A; Bolshov, M A

    2016-06-01

    The reversible sorption preconcentration of noble metals (NMs) prior to their determination by inductively coupled plasma-mass spectrometry (ICP-MS) was investigated. Six new hypercrosslinked polystyrene sorbents were tested. The dependence of the degree of NMs sorption on the average degree of polymer network crosslinking and pore diameters was investigated. It was found that sorbents HP-100/6, HP-300/6 and HP-500/6 have low efficiency of NMs chlorocomplexes extraction. Among Stirosorb sorbents (Stirosorb-2, Stirosorb-514 and Stirosorb-584) the highest efficiency of the extraction of NMs' chlorocomplexes has Stirosorb-514. Tributylamine (TBA), N-methylbenzylamine (MBA), N,N-dimethylbenzylamine (DMBA), N,N-dibenzylmetylamine (DBMA) were studied as the reagents for extraction of Ru, Rh, Pd, Ir, Pt and Au chlorocomplexes from hydrochloric acid solutions in the form of ion associates by reversed-phase mechanism. The reversible quantitative extraction of Ru, Pd, Pt and Au in system Stirosorb-514 - TBA - 1M HCl in ethanol as eluent was achieved. It was found that resulting eluates do not contain matrix components which may cause spectral interferences on the stage of NMs determination by ICP-MS. The found scheme of NMs reversible sorption was validated by the analysis of certified reference materials of basic and ultrabasic rocks GPt-5, GPt-6 and SARM-7. Good agreement between the measured NMs concentrations and the certified values was demonstrated. The achieved limits of detection for Ru, Pd, Pt and Au vary within 10(-8)-10(-7)wt% range.

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

    PubMed

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

    2016-09-01

    In the event of the interception of illicit nuclear materials or detonation of a nuclear device, timely and accurate deciphering of the chemical and isotopic composition of pertinent samples is pivotal in enhancing both nuclear security and source attribution. This study reports the results from a first time (to our knowledge), detailed comparative investigation conducted of Trinitite post-detonation materials using both solution mode (SM) and laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) techniques. Trace element abundances determined for bulk Trinitite samples subsequent to digestion and preparation for SM-ICP-MS analysis compare favorably to calculated median concentrations based on LA-ICP-MS analyses for the identical samples. The trace element concentrations obtained by individual LA-ICP-MS analyses indicate a large scatter compared to the corresponding bulk sample SM-ICP-MS results for the same sample; this feature can be attributed to the incorporation into the blast melt of specific, precursor accessory minerals (minerals in small quantities, such as carbonates, sulfates, chlorites, clay, and mafic minerals) present at ground zero. The favorable comparison reported here validates and confirms the use of the LA-ICP-MS technique in obtaining accurate forensic information at high spatial resolution in nuclear materials for source attribution purposes. This investigation also reports device-like (240)Pu/(239)Pu ratios (∼0.022) for Pu-rich regions of the blast melt that are also characterized by higher Ca and U contents, which is consistent with results from previous studies. © The Author(s) 2016.

  8. Application of mass spectrometry for metabolite identification.

    PubMed

    Ma, Shuguang; Chowdhury, Swapan K; Alton, Kevin B

    2006-06-01

    Metabolism studies play a pivotal role in drug discovery and development. Characterization of metabolic "hot-spots" as well as reactive and pharmacologically active metabolites is critical to designing new drug candidates with improved metabolic stability, toxicological profile and efficacy. Metabolite identification in the preclinical species used for safety evaluation is required in order to determine whether human metabolites have been adequately tested during non-clinical safety assessment. From an instrumental standpoint, high performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) dominates all analytical tools used for metabolite identification. The general strategies employed for metabolite identification in both drug discovery and drug development settings together with sample preparation techniques are reviewed herein. These include a discussion of the various ionization methods, mass analyzers, and tandem mass spectrometry (MS/MS) techniques that are used for structural characterization in a modern drug metabolism laboratory. Mass spectrometry-based techniques, such as stable isotope labeling, on-line H/D exchange, accurate mass measurement to enhance metabolite identification and recent improvements in data acquisition and processing for accelerating metabolite identification are also described. Rounding out this review, we offer additional thoughts about the potential of alternative and less frequently used techniques such as LC-NMR/MS, CRIMS and ICPMS.

  9. Isotope ratio measurements by secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS)

    NASA Astrophysics Data System (ADS)

    Betti, Maria

    2005-04-01

    The basic principles of secondary ion mass spectrometry and glow discharge mass spectrometry have been shortly revisited. The applications of both techniques as exploited for the isotope ratio measurements in several matrices have been reviewed. Emphasis has been given to research fields in expansions such as solar system studies, medicine, biology, environment and nuclear forensic. The characteristics of the two techniques are discussed in terms of sensitivity and methodology of quantification. Considerations on the different detection possibilities in SIMS are also presented.

  10. Compositions and Structures of Vanadium Oxide Cluster Ions VmOn(±) (m = 2-20) Investigated by Ion Mobility Mass Spectrometry.

    PubMed

    Wu, Jenna W J; Moriyama, Ryoichi; Tahara, Hiroshi; Ohshimo, Keijiro; Misaizu, Fuminori

    2016-06-02

    Stable compositions and geometrical structures of vanadium oxide cluster ions, VmOn(±), were investigated by ion mobility mass spectrometry (IM-MS). The most stable compositions of vanadium oxide cluster cations were (V2O4)(V2O5)(m-2)/2(+) and (VO2)(V2O5)(m-1)/2(+), depending on the clusters with even and odd numbers of vanadium atoms. Compositions one-oxygen richer than the cations, such as (V2O5)m/2(-) and (VO3)(V2O5)(m-1)/2(-), were predominantly observed for cluster anions. Assignments of these stable cluster ion compositions, which were determined as a result of collision-induced dissociations in IM-MS, can partly be explained with consideration of spin density distribution. By comparing the experimental collision cross sections (CCSs) obtained from ion mobility measurement with CCSs of the theoretically calculated structures, we confirmed the patterned growth of geometrical structures partially discussed in previous theoretical and spectroscopic studies. We showed that even sized (V2O5)m/2(±) where m = 6-12 had right polygonal prism structures except for the anionic V12O30(-), and for the clusters of odd numbers of vanadium m, cations and anions can either have bridged or pyramid structures. Both of the odd sized structures proposed were derivatives from the even sized right polygonal prism structures. The exception, V12O30(-), which had a CCS almost equal to that of the neighboring smaller V11O28(-), should have a structure of higher density than the right hexagonal prism, in which it was proposed to be a captured pyramid structure, derived from V11O28(-).

  11. Liquid chromatography-quadrupole time-of-flight mass spectrometry for screening in vitro drug metabolites in humans: investigation on seven phenethylamine-based designer drugs.

    PubMed

    Lai, Foon Yin; Erratico, Claudio; Kinyua, Juliet; Mueller, Jochen F; Covaci, Adrian; van Nuijs, Alexander L N

    2015-10-10

    Phenethylamine-based designer drugs are prevalent within the new psychoactive substance market. Characterisation of their metabolites is important in order to identify suitable biomarkers which can be used for better monitoring their consumption. Careful design of in vitro metabolism experiments using subcellular liver fractions will assist in obtaining reliable outcomes for such purposes. The objective of this study was to stepwise investigate the in vitro human metabolism of seven phenethylamine-based designer drugs using individual families of enzymes. This included para-methoxyamphetamine, para-methoxymethamphetamine, 4-methylthioamphetamine, N-methyl-benzodioxolylbutanamine, benzodioxolylbutanamine, 5-(2-aminopropyl) benzofuran and 6-(2-aminopropyl) benzofuran. Identification and structural elucidation of the metabolites was performed using liquid chromatography-quadrupole-time-of-flight mass spectrometry. The targeted drugs were mainly metabolised by cytochrome P450 enzymes via O-dealkylation as the major pathway, followed by N-dealkylation, oxidation of unsubstituted C atoms and deamination (to a small extent). These drugs were largely free from Phase II metabolism. Only a limited number of metabolites were found which was consistent with the existing literature for other phenethylamine-based drugs. Also, the metabolism of most of the targeted drugs progressed at slow rate. The reproducibility of the identified metabolites was assessed through examining formation patterns using different incubation times, substrate and enzyme concentrations. Completion of the work has led to a set of metabolites which are representative for specific detection of these drugs in intoxicated individuals and also for meaningful evaluation of their use in communities by wastewater-based drug epidemiology. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. A liquid chromatography-tandem mass spectrometry-based investigation of the lamellar interstitial metabolome in healthy horses and during experimental laminitis induction.

    PubMed

    Medina-Torres, C E; van Eps, A W; Nielsen, L K; Hodson, M P

    2015-11-01

    Lamellar bioenergetic failure is thought to contribute to laminitis pathogenesis but current knowledge of lamellar bioenergetic physiology is limited. Metabolomic analysis (MA) can systematically profile multiple metabolites. Applied to lamellar microdialysis samples (dialysate), lamellar bioenergetic changes during laminitis (the laminitis metabolome) can be characterised. The objectives of this study were to develop a technique for targeted MA of lamellar and skin dialysates in normal horses, and to compare the lamellar and plasma metabolomic profiles of normal horses with those from horses developing experimentally induced laminitis. Archived lamellar and skin dialysates (n = 7) and tissues (n = 6) from normal horses, and lamellar dialysate and plasma from horses given either 10 g/kg oligofructose (treatment group, OFT; n = 4) or sham (control group, CON; n = 4) were analysed. The concentrations of 44 intermediates of central carbon metabolism (CCM) were determined using liquid chromatography-tandem mass spectrometry. Data were analysed using multivariate (MVA) and univariate (UVA) analysis methods. The plasma metabolome appeared to be more variable than the lamellar metabolome by MVA, driven by malate, pyruvate, aconitate and glycolate. In lamellar dialysate, these metabolites decreased in OFT horses at the later time points. Plasma malate was markedly increased after 6 h in OFT horses. Plasma malate concentrations between OFT and CON at this time point were significantly different by UVA. MA of lamellar CCM was capable of differentiating horses developing experimental laminitis from controls. Lamellar malate, pyruvate, aconitate and glycolate, and plasma malate alone were identified as the source of differentiation between OFT and CON groups. These results highlighted clear discriminators between OFT and CON horses, suggesting that changes in energy metabolism occur locally in the lamellar tissue during laminitis development. The biological

  13. Investigation of volatile organic metabolites in lung cancer pleural effusions by solid-phase microextraction and gas chromatography/mass spectrometry.

    PubMed

    Liu, Huijun; Wang, Hong; Li, Caixia; Wang, Lichao; Pan, Zaifa; Wang, Lili

    2014-01-15

    Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/mass spectrometry (GC/MS) method was applied for the investigation of low molecular weight volatile organic metabolites (VOMs) in pleural effusion samples. Three important HS-SPME experimental parameters that influence extraction efficiency (fiber coating, extraction time and temperature of sampling) were optimized by a univariate optimization design. The highest extraction efficiency was obtained when sampling was performed at 50°C for 10min under agitation using a carboxen/polydimethylsiloxane (CAR/PDMS) fiber. A total of 36 volatile metabolites belonging to nine distinct chemical classes were identified in 40 pleural effusion samples (20 malignant effusions from lung cancer patients and 20 benign effusions from inflammatory patients). Ketones, alcohols, and benzene derivatives were the main chemical classes for the metabolomic profile of malignant effusions. The average peak areas of ketones and alcohols were much higher in malignant group compared to benign group. Together with phenols, they exhibit significant differences (P<0.05) between the two groups. Particularly, the average peak areas of cyclohexanone and 2-ethyl-1-hexanol in malignant effusions were significantly higher than those in benign ones. Furthermore, of the 36 identified metabolites, 5 compounds including cyclohexanone and 2-ethyl-1-hexanol were found to be statistically different (Student's t-test, P<0.05) between the two groups by statistical analysis based on the peak areas of all identified metabolites. Among them, cyclohexanone and 2-ethyl-1-hexanol might be considered as candidate biomarkers of lung cancer to differentiate malignant from benign effusions. The results show that HS-SPME-GC/MS is a simple, rapid, sensitive and solvent-free method for the determination of VOMs in pleural effusion samples. Pleural effusion is a valuable sample source for observation of changes in VOMs for differentiation between

  14. Investigating Differences in Gas-Phase Conformations of 25-Hydroxyvitamin D3 Sodiated Epimers using Ion Mobility-Mass Spectrometry and Theoretical Modeling

    NASA Astrophysics Data System (ADS)

    Chouinard, Christopher D.; Cruzeiro, Vinícius Wilian D.; Beekman, Christopher R.; Roitberg, Adrian E.; Yost, Richard A.

    2017-08-01

    Drift tube ion mobility coupled with mass spectrometry was used to investigate the gas-phase structure of 25-hydroxyvitamin D3 (25OHD3) and D2 (25OHD2) epimers, and to evaluate its potential in rapid separation of these compounds. Experimental results revealed two distinct drift species for the 25OHD3 sodiated monomer, whereas only one of these conformations was observed for its epimer (epi25OHD3). The unique species allowed 25OHD3 to be readily distinguished, and the same pattern was observed for 25OHD2 epimers. Theoretical modeling of 25OHD3 epimers identified energetically stable gas-phase structures, indicating that both compounds may adopt a compact "closed" conformation, but that 25OHD3 may also adopt a slightly less energetically favorable "open" conformation that is not accessible to its epimer. Calculated theoretical collision cross-sections for these structures agreed with experimental results to <2%. Experimentation indicated that additional energy in the ESI source (i.e., increased temperature, spray voltage) affected the ratio of 25OHD3 conformations, with the less energetically favorable "open" conformation increasing in relative intensity. Finally, LC-IM-MS results yielded linear quantitation of 25OHD3, in the presence of the epimer interference, at biologically relevant concentrations. This study demonstrates that ion mobility can be used in tandem with theoretical modeling to determine structural differences that contribute to drift separation. These separation capabilities provide potential for rapid (<60 ms) identification of 25OHD3 and 25OHD2 in mixtures with their epimers.

  15. Initial results of positron ionization mass spectrometry

    NASA Technical Reports Server (NTRS)

    Donohue, D. L.; Hulett, L. D., Jr.; Mcluckey, S. A.; Glish, G. L.; Eckenrode, B. A.

    1990-01-01

    The use of monoenergetic positrons for the ionization of organic molecules in the gas phase is described. The ionic products are analyzed with a time-of-flight mass spectrometer and detected to produce a mass spectrum. The ionization mechanisms which can be studied in this way include positron impact at energies above the ionization limit of the target molecules, positronium formation in the Ore gap energy range, and positron attachment at energies less than 1eV. The technique of positron ionization mass spectrometry (PIMS) may have analytical utility in that chemical selectivity is observed for one or more of these processes.

  16. Application of Lithium Attachment Mass Spectrometry for Knudsen Evaporation and Chemical Ionisation Mass Spectrometry (KEMS, CIMS)

    NASA Astrophysics Data System (ADS)

    Bannan, T.; Booth, M.; Benyezzar, M.; Bacak, A.; Alfarra, M. R. R.; Topping, D. O.; Percival, C.

    2015-12-01

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting and sensitive method for detection of volatile species in the gas phase. The design, manufacture, and results from lithium ion attachment ionisation sources for two mass spectrometry systems are presented. Trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure (VP) measurements using a modified Knudsen Effusion Mass Spectrometer (KEMS) are presented. The Li+ modified CIMS provided limits of detection of 4 ppt for acetone, 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt from ammonia. Despite improvements, the problem of burnout remained persistent. The Li+ CIMS would unlikely be suitable for field or aircraft work, but could be appropriate for certain lab applications. The KEMS currently utilizes an electron impact (EI) ionisation source which provides a highly sensitive source, with the drawback of fragmentation of ionized molecules (Booth et al., 2009). Using Li+ KEMS the VP of samples can be measured without fragmentation and can therefore be used to identify VPs of individual components in mixtures. The validity of using Li+ for determining the VP of mixtures was tested by making single component VP measurements, which showed good agreement with EI measurements of Poly ethylene glycol (PEG) 3 and PEG 4, both when individually measured and when mixed. The Li+ KEMS was then used to investigate a system of atmospheric relevance, α-pinene secondary organic aerosol, generated in a reaction chamber (Alfarra et al., 2012). The VPs of the individual components from this generated sample are within the range we expect for compounds capable of partitioning between the particle and gas phase of an aerosol (0.1-10-5 Pa). Li+ source has a calculated sensitivity approximately 75 times less than that of EI, but the lack of fragmentation using the Li+ source is a significant advantage.

  17. Application of Lithium Attachment Mass Spectrometry for Knudsen Evaporation and Chemical Ionisation Mass Spectrometry (KEMS, CIMS)

    NASA Astrophysics Data System (ADS)

    Bannan, Thomas; Booth, A. Murray; Alfarra, Rami; Bacak, Asan; Pericval, Carl

    2016-04-01

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting and sensitive method for detection of volatile species in the gas phase. The design, manufacture, and results from lithium ion attachment ionisation sources for two mass spectrometry systems are presented. Trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure (VP) measurements using a modified Knudsen Effusion Mass Spectrometer (KEMS) are presented. The Li+ modified CIMS provided limits of detection of 4 ppt for acetone, 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt from ammonia. Despite improvements, the problem of burnout remained persistent. The Li+ CIMS would unlikely be suitable for field or aircraft work, but could be appropriate for certain lab applications. The KEMS currently utilizes an electron impact (EI) ionisation source which provides a highly sensitive source, with the drawback of fragmentation of ionized molecules (Booth et al., 2009). Using Li+ KEMS the VP of samples can be measured without fragmentation and can therefore be used to identify VPs of individual components in mixtures. The validity of using Li+ for determining the VP of mixtures was tested by making single component VP measurements, which showed good agreement with EI measurements of Poly ethylene glycol (PEG) 3 and PEG 4, both when individually measured and when mixed. The Li+ KEMS was then used to investigate a system of atmospheric relevance, α-pinene secondary organic aerosol, generated in a reaction chamber (Alfarra et al., 2012). The VPs of the individual components from this generated sample are within the range we expect for compounds capable of partitioning between the particle and gas phase of an aerosol (0.1-10-5 Pa). Li+ source has a calculated sensitivity approximately 75 times less than that of EI, but the lack of fragmentation using the Li+ source is a significant advantage.

  18. Nuclear applications of inorganic mass spectrometry.

    PubMed

    De Laeter, John

    2010-01-01

    There are several basic characteristics of mass spectrometry that are not always fully appreciated by the science community. These characteristics include the distinction between relative and absolute isotope abundances, and the influence of isotope fractionation on the accuracy of isotopic measurements. These characteristics can be illustrated in the field of nuclear physics with reference to the measurement of nuclear parameters, which involve the use of enriched isotopes, and to test models of s-, r-, and p-process nucleosynthesis. The power of isotope-dilution mass spectrometry (IDMS) to measure trace elements in primitive meteorites to produce accurate Solar System abundances has been essential to the development of nuclear astrophysics. The variety of mass spectrometric instrumentation used to measure the isotopic composition of elements has sometimes been accompanied by a lack of implementation of basic mass spectrometric protocols which are applicable to all instruments. These metrological protocols are especially important in atomic weight determinations, but must also be carefully observed in cases where the anomalies might be very small, such as in studies of the daughter products of extinct radionuclides to decipher events in the early history of the Solar System. There are occasions in which misleading conclusions have been drawn from isotopic data derived from mass spectrometers where such protocols have been ignored. It is important to choose the mass spectrometer instrument most appropriate to the proposed experiment. The importance of the integrative nature of mass spectrometric measurements has been demonstrated by experiments in which long, double beta decay and geochronological decay half-lives have been measured as an alternative to costly radioactive-counting experiments. This characteristic is also illustrated in the measurement of spontaneous fission yields, which have accumulated over long periods of time. Mass spectrometry is also a

  19. Investigation of the depth range through ultra-thin carbon films on magnetic layers by time-of-flight secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Tadokoro, N.; Yuki, M.; Osakabe, K.

    2003-01-01

    This paper presents an examination of the depth range of magnetic layers through ultra-thin carbon films by time-of-flight secondary ion mass spectrometry (TOF-SIMS). X-ray photoelectron spectroscopy (XPS) was used for comparison of TOF-SIMS. The sampling depth of TOF-SIMS is somewhat smaller than that of XPS. And also, the sampling depth obtained from this analysis is larger than that of the static SIMS (less than 1 nm) [Surf. Interf. Anal. 10 (1987) 384]. Our results suggest that the sampling depth is related to the sample structure (defects or pinholes of nanometer scale), the sensitivity of analytical tools and the emission process.

  20. Linking Mass Spectrometry with Toxicology for Emerging Water Contaminants

    EPA Science Inventory

    This overview presentation will discuss the benefits of combining mass spectrometry with toxicology. These benefits will be described for 3 main areas: (1) Toxicity assays used to test new environmental contaminants previously identified using mass spectrometry, such that furth...

  1. Linking Mass Spectrometry with Toxicology for Emerging Water Contaminants

    EPA Science Inventory

    This overview presentation will discuss the benefits of combining mass spectrometry with toxicology. These benefits will be described for 3 main areas: (1) Toxicity assays used to test new environmental contaminants previously identified using mass spectrometry, such that furth...

  2. Structure Determination of Natural Products by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Biemann, Klaus

    2015-07-01

    I review laboratory research on the development of mass spectrometric methodology for the determination of the structure of natural products of biological and medical interest, which I conducted from 1958 to the end of the twentieth century. The methodology was developed by converting small peptides to their corresponding polyamino alcohols to make them amenable to mass spectrometry, thereby making it applicable to whole proteins. The structures of alkaloids were determined by analyzing the fragmentation of a known alkaloid and then using the results to deduce the structures of related compounds. Heparin-like structures were investigated by determining their molecular weights from the mass of protonated molecular ions of complexes with highly basic, synthetic peptides. Mass spectrometry was also employed in the analysis of lunar material returned by the Apollo missions. A miniaturized gas chromatograph mass spectrometer was sent to Mars on board of the two Viking 1976 spacecrafts.

  3. Ultrahigh-Mass Mass Spectrometry of Single Biomolecules and Bioparticles

    NASA Astrophysics Data System (ADS)

    Chang, Huan-Cheng

    2009-07-01

    Since the advent of soft ionization methods, mass spectrometry (MS) has found widespread application in the life sciences. Mass is now known to be a critical parameter for characterization of biomolecules and their complexes; it is also a useful parameter to characterize bioparticles such as viruses and cells. However, because of the genetic diversity of these entities, it is necessary to measure their masses individually and to obtain the corresponding mean masses and mass distributions. Here, I review recent technological developments that enable mass measurement of ultrahigh-mass biomolecules and bioparticles at the single-ion level. Some representative examples include cryodetection time-of-flight MS of single-megadalton protein ions, Millikan-type mass measurements of single viruses in a cylindrical ion trap, and charge-detection quadrupole ion trap MS of single whole cells. I also discuss the promises and challenges of these new technologies in real-world applications.

  4. Biological particle analysis by mass spectrometry

    NASA Technical Reports Server (NTRS)

    Vilker, V. L.; Platz, R. M.

    1983-01-01

    An instrument that analyzes the chemical composition of biological particles in aerosol or hydrosol form was developed. Efforts were directed toward the acquisition of mass spectra from aerosols of biomolecules and bacteria. The filament ion source was installed on the particle analysis by mass spectrometry system. Modifications of the vacuum system improved the sensitivity of the mass spectrometer. After the modifications were incorporated, detailed mass spectra of simple compounds from the three major classes of biomolecules, proteins, nucleic acids, and carbohydrates were obtained. A method of generating bacterial aerosols was developed. The aerosols generated were collected and examined in the scanning electron microscope to insure that the bacteria delivered to the mass spectrometer were intact and free from debris.

  5. Laser-Cooling-Assisted Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Schneider, Christian; Schowalter, Steven J.; Chen, Kuang; Sullivan, Scott T.; Hudson, Eric R.

    2014-09-01

    Mass spectrometry is used in a wide range of scientific disciplines including proteomics, pharmaceutics, forensics, and fundamental physics and chemistry. Given this ubiquity, there is a worldwide effort to improve the efficiency and resolution of mass spectrometers. However, the performance of all techniques is ultimately limited by the initial phase-space distribution of the molecules being analyzed. Here, we dramatically reduce the width of this initial phase-space distribution by sympathetically cooling the input molecules with laser-cooled, cotrapped atomic ions, improving both the mass resolution and detection efficiency of a time-of-flight mass spectrometer by over an order of magnitude. Detailed molecular-dynamics simulations verify the technique and aid with evaluating its effectiveness. This technique appears to be applicable to other types of mass spectrometers.

  6. Mass spectrometry in Chronic Kidney Disease research

    PubMed Central

    Merchant, Michael L.

    2010-01-01

    Proteomics has evolved into an invaluable tool for biomedical research and for research on renal diseases. A central player in the proteomic revolution is the mass spectrometer and its application to analyze biological samples. Our need to understand both the identity of proteins and their abundance has led to improvements in mass spectrometers and their ability to analyze complex tryptic peptide mixtures with high sensitivity and high mass accuracy in a high throughput fashion (such as the LTQ-Orbitrap). It should not be surprising that this occurred coincident with dramatic improvements in our understanding chronic kidney disease (CKD), the mechanisms through which CKD progresses and the development of candidate CKD biomarkers. This review attempts to present a basic framework for the operational components of mass spectrometers, basic insight into how they are used in renal research and a discussion of CKD research that was driven by mass spectrometry. PMID:21044768

  7. Detection of Gunshot Residues Using Mass Spectrometry

    PubMed Central

    Blanes, Lucas; Cole, Nerida; Doble, Philip; Roux, Claude

    2014-01-01

    In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR), although the “gold standard” for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX). This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis. PMID:24977168

  8. Proton Dynamics in Protein Mass Spectrometry.

    PubMed

    Li, Jinyu; Lyu, Wenping; Rossetti, Giulia; Konijnenberg, Albert; Natalello, Antonino; Ippoliti, Emiliano; Orozco, Modesto; Sobott, Frank; Grandori, Rita; Carloni, Paolo

    2017-03-16

    Native electrospray ionization/ion mobility-mass spectrometry (ESI/IM-MS) allows an accurate determination of low-resolution structural features of proteins. Yet, the presence of proton dynamics, observed already by us for DNA in the gas phase, and its impact on protein structural determinants, have not been investigated so far. Here, we address this issue by a multistep simulation strategy on a pharmacologically relevant peptide, the N-terminal residues of amyloid-β peptide (Aβ(1-16)). Our calculations reproduce the experimental maximum charge state from ESI-MS and are also in fair agreement with collision cross section (CCS) data measured here by ESI/IM-MS. Although the main structural features are preserved, subtle conformational changes do take place in the first ∼0.1 ms of dynamics. In addition, intramolecular proton dynamics processes occur on the picosecond-time scale in the gas phase as emerging from quantum mechanics/molecular mechanics (QM/MM) simulations at the B3LYP level of theory. We conclude that proton transfer phenomena do occur frequently during fly time in ESI-MS experiments (typically on the millisecond time scale). However, the structural changes associated with the process do not significantly affect the structural determinants.

  9. Signatures for Mass Spectrometry Data Quality

    PubMed Central

    2014-01-01

    Ensuring data quality and proper instrument functionality is a prerequisite for scientific investigation. Manual quality assurance is time-consuming and subjective. Metrics for describing liquid chromatography mass spectrometry (LC–MS) data have been developed; however, the wide variety of LC–MS instruments and configurations precludes applying a simple cutoff. Using 1150 manually classified quality control (QC) data sets, we trained logistic regression classification models to predict whether a data set is in or out of control. Model parameters were optimized by minimizing a loss function that accounts for the trade-off between false positive and false negative errors. The classifier models detected bad data sets with high sensitivity while maintaining high specificity. Moreover, the composite classifier was dramatically more specific than single metrics. Finally, we evaluated the performance of the classifier on a separate validation set where it performed comparably to the results for the testing/training data sets. By presenting the methods and software used to create the classifier, other groups can create a classifier for their specific QC regimen, which is highly variable lab-to-lab. In total, this manuscript presents 3400 LC–MS data sets for the same QC sample (whole cell lysate of Shewanella oneidensis), deposited to the ProteomeXchange with identifiers PXD000320–PXD000324. PMID:24611607

  10. 1912: a Titanic year for mass spectrometry.

    PubMed

    Downard, Kevin M

    2012-08-01

    The 1912 sinking of the Titanic continues to capture the imagination and fascination of the general public. The year coincides with the birth of mass spectrometry that began with the cathode ray experiments performed by Joseph John (J. J.) Thomson in Cambridge. Modifications made to Thomson's cathode ray apparatus by Francis William Aston, resulted in an increase in the brightness of the positive rays that aided their detection. This led to the discovery of heavy isotopes for many of the chemical elements in the ensuing decades. As the discovery of (22) Ne was reported in 1913, another of Thomson's students was taking part in an expedition to help save future ocean liners from the fate of the Titanic. Geoffrey Ingram Taylor took part in the first ice patrol of the North Atlantic in 1913 aboard the SS Scotia to investigate the formation and position of icebergs. This article, 100 years on, describes Taylor's work and its impact on safe ocean passage across the Atlantic. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Single-Cell Imaging Mass Spectrometry

    PubMed Central

    Passarelli, Melissa K.; Ewing, Andrew G.

    2013-01-01

    Single-cell imaging mass spectrometry (IMS) is a powerful technique used to map the distributions of endogenous biomolecules with sub-cellular resolution. Currently, secondary ion mass spectrometry is the predominant technique for single-cell IMS, thanks to its sub-micron lateral resolution and surface sensitivity. However, recent methodological and technological developments aimed at improving the spatial resolution of matrix assisted laser desorption ionization (MALDI) have made this technique a potential platform of single-cell IMS. MALDI opens the field of single-cell IMS to new possibilities, including single cell proteomic imaging and atmospheric pressure analyses; however, sensitivity is a challenge. In this report, we estimate the availability of proteins and lipids in a single cell and discuss strategies employed to improve sensitivity at the single-cell level. PMID:23948695

  12. Dissecting the ubiquitin pathway by mass spectrometry

    PubMed Central

    Xu, Ping; Peng, Junmin

    2007-01-01

    Summary Protein modification by ubiquitin is a central regulatory mechanism in eukaryotic cells. Recent proteomics developments in mass spectrometry enable systematic analysis of cellular components in the ubiquitin pathway. Here, we review the advances in analyzing ubiquitinated substrates, determining modified lysine residues, quantifying polyubiquitin chain topologies, as well as profiling deubiquitinating enzymes based on the activity. Moreover, proteomic approaches have been developed for probing the interactome of proteasome and for identifying proteins with ubiquitin-binding domains. Similar strategies have been applied on the studies of the modification by ubiquitin-like proteins as well. These strategies are discussed with respect to their advantages, limitations and potential improvements. While the utilization of current methodologies has rapidly expanded the scope of protein modification by the ubiquitin family, a more active role is anticipated in the functional studies with the emerging of quantitative mass spectrometry. PMID:17055348

  13. Impact of automation on mass spectrometry.

    PubMed

    Zhang, Yan Victoria; Rockwood, Alan

    2015-10-23

    Mass spectrometry coupled to liquid chromatography (LC-MS and LC-MS/MS) is an analytical technique that has rapidly grown in popularity in clinical practice. In contrast to traditional technology, mass spectrometry is superior in many respects including resolution, specificity, multiplex capability and has the ability to measure analytes in various matrices. Despite these advantages, LC-MS/MS remains high cost, labor intensive and has limited throughput. This specialized technology requires highly trained personnel and therefore has largely been limited to large institutions, academic organizations and reference laboratories. Advances in automation will be paramount to break through this bottleneck and increase its appeal for routine use. This article reviews these challenges, shares perspectives on essential features for LC-MS/MS total automation and proposes a step-wise and incremental approach to achieve total automation through reducing human intervention, increasing throughput and eventually integrating the LC-MS/MS system into the automated clinical laboratory operations.

  14. Exploring the potential of high resolution mass spectrometry for the investigation of lignin-derived phenol substitutes in phenolic resin syntheses.

    PubMed

    Dier, Tobias K F; Fleckenstein, Marco; Militz, Holger; Volmer, Dietrich A

    2017-03-23

    Chemical degradation is an efficient method to obtain bio-oils and other compounds from lignin. Lignin bio-oils are potential substitutes for the phenol component of phenol formaldehyde (PF) resins. Here, we developed an analytical method based on high resolution mass spectrometry that provided structural information for the synthesized lignin-derived resins and supported the prediction of their properties. Different model resins based on typical lignin degradation products were analyzed by electrospray ionization in negative ionization mode. Utilizing enhanced mass defect filter techniques provided detailed structural information of the lignin-based model resins and readily complemented the analytical data from differential scanning calorimetry and thermogravimetric analysis. Relative reactivity and chemical diversity of the phenol substitutes were significant determinants of the outcome of the PF resin synthesis and thus controlled the areas of application of the resulting polymers. Graphical abstract ᅟ.

  15. Anatoxins and degradation products, determined using hybrid quadrupole time-of-flight and quadrupole ion-trap mass spectrometry: forensic investigations of cyanobacterial neurotoxin poisoning.

    PubMed

    James, Kevin J; Crowley, Janet; Hamilton, Brett; Lehane, Mary; Skulberg, Olav; Furey, Ambrose

    2005-01-01

    The potent neurotoxins from cyanobacteria, anatoxin-a (AN), its methyl analogue, homoanatoxin-a (HMAN), and their degradation products, have been studied using nano-electrospray hybrid quadrupole time-of-flight mass spectrometry (QqTOF-MS). The anatoxin degradation products, which are readily produced in vivo by either reduction or epoxidation, were also examined in this study. The high mass accuracy QqTOF-MS data was used to confirm formula assignments for major product ions and quadrupole ion-trap (QIT)-MS was used to construct fragmentation pathways for anatoxins. Significant differences between these fragmentation pathways were observed. Comparisons between the spectra of compounds that differ in side-chain length (the AN and HMAN series) were used to identify ions that are characteristic of the homologues. The application to forensic samples in which the principal neurotoxin had undergone rapid biodegradation has been demonstrated and used to confirm anatoxin poisoning of dogs. Copyright 2005 John Wiley & Sons, Ltd.

  16. An investigation into artefacts formed during gas chromatography/mass spectrometry analysis of firearms propellant that contains diphenylamine as the stabiliser.

    PubMed

    Pigou, Paul; Dennison, Genevieve H; Johnston, Martin; Kobus, Hilton

    2017-10-01

    In the course of providing assistance to legal counsel in a matter that involved the analysis of firearms propellant by gas chromatography/mass spectrometry it was noticed that phenoxazine was reported as a component of 0.22 calibre propellant that contained diphenylamine as the stabiliser. The research was conducted to find how phenoxazine was formed. The results showed that the compound was not phenoxazine but a diphenylamine derivative 4-(phenylimino) cyclohexa-2,5-dien-1-one that formed in the injection port of the gas chromatograph. In addition a second artefact was found to form in the ion source of the mass spectrometer. While the presence of the artefacts does not affect the ability to identify particles as propellant they may impact on comparison with source ammunition. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Proton-transfer-reaction mass spectrometry (PTR-MS) of carboxylic acids: Determination of Henry's law constants and axillary odour investigations

    NASA Astrophysics Data System (ADS)

    Hartungen, Eugen Von; Wisthaler, Armin; Mikoviny, Tomas; Jaksch, Dagmar; Boscaini, Elena; Dunphy, Patrick J.; Märk, Tilmann D.

    2004-12-01

    Proton-transfer-reaction mass spectrometry (PTR-MS) was used as an analytical tool to measure gas-phase concentrations of short-chain fatty acids. Chemical ionisation of C2C6 carboxylic acids by PTR-MS produced intense protonated molecular ions (with traces of hydrates) along with acylium ion fragments. Gas-phase concentrations were derived using the established method for calculating PTR-MS sensitivity factors. Henry's law constants of carboxylic acids for aqueous solutions at 40 °C were determined. Direct monitoring of volatile fatty acids, known to be associated with secretions from the human axilla, was performed via a specially designed transfer device situated in the axilla. Mass spectral data corresponded with the findings of a sensory assessor.

  18. Accelerator mass spectrometry - from DNA to astrophysics

    NASA Astrophysics Data System (ADS)

    Kutschera, Walter

    2013-12-01

    A brief review of accelerator mass spectrometry (AMS) is presented. The present work touches on a few technical aspects and recent developments of AMS, and describes two specific applications of AMS, the dating of human DNA with the 14C bomb peak and the search for superheavy elements in nature. Since two extended general reviews on technical developments in AMS [1] and applications of AMS [2] will appear in 2013, frequent reference to these reviews is made.

  19. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  20. Radiation Biomarker Research Using Mass Spectrometry

    DTIC Science & Technology

    2007-07-01

    The data was of insufficient quality to obtain definitive biomarkers. Trips were also made to AFRL/HEDR at Brooks City Base to assist with their...sample analysis using the Finnigan LTQ located there. Mr. Mullens and Ms. Nagore assisted with training personnel at AFRL/HEDR and when necessary...techniques with saliva samples and matrix- assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), we have been able to

  1. [Photon burst mass spectrometry technique.] Final report

    SciTech Connect

    Fairbank, W.M. Jr

    1996-04-01

    The basic tools have been developed and demonstrated for selective detection of Kr isotopes in the Photon Burst Mass Spectrometry technique. The effort is divided into: photon burst measurements on Mg{sup +} demonstrating high isotopic selectivity, charge exchange of Kr{sup +} with Cs and Rb to produce metastable Kr atoms, development of a diode laser system for photon burst detection of Kr{sup +}, and measurements of photon bursts detection of Kr.

  2. Investigation of the electrochemical oxidation products of zotepine and their fragmentation using on-line electrochemistry/electrospray ionization mass spectrometry.

    PubMed

    Nozaki, Kazuyoshi; Kitagawa, Hiroshi; Kimura, Sumihisa; Kagayama, Akira; Arakawa, Ryuichi

    2006-05-01

    When zotepine, an antipsychotic drug, was electrochemically oxidized using electrospray ionization mass spectrometry (ESI-MS) coupled with a microflow electrolytic cell, [M + 16 + H]+ (m/z 348), [M-H]+ (m/z 330) and [M-14 + H]+ (m/z 318) were observed as electrochemical oxidation product ions (M represents the zotepine molecule). Although a major fragment ion that was derived from the dimethyl aminoethyl moiety was observed only at m/z 72 in the collision-induced dissociation (CID) spectrum of zotepine, new fragments such as m/z 315 and 286 ions could be generated in the CID spectrum by combining electrochemical oxidation and CID. Since these fragments were relatively specific with high ion strength, it was thought that they would be useful for developing a sensitive LC-MS/MS assay. The S-oxide and N-demethylated products were detected by electrolysis assuring that a portion of P450 metabolites of zotepine could be mimicked by the electrochemistry/electrospray ionization mass spectrometry (EC/ESI-MS) system.

  3. Preparation and properties of pure, full-length IclR protein of Escherichia coli. Use of time-of-flight mass spectrometry to investigate the problems encountered.

    PubMed

    Donald, L J; Chernushevich, I V; Zhou, J; Verentchikov, A; Poppe-Schriemer, N; Hosfield, D J; Westmore, J B; Ens, W; Duckworth, H W; Standing, K G

    1996-08-01

    IclR protein, the repressor of the aceBAK operon of Escherichia coli, has been examined by time-of-flight mass spectrometry, with ionization by matrix assisted laser desorption or by electrospray. The purified protein was found to have a smaller mass than that predicted from the base sequence of the cloned iclR gene. Additional measurements were made on mixtures of peptides derived from IclR by treatment with trypsin and cyanogen bromide. They showed that the amino acid sequence is that predicted from the gene sequence, except that the protein has suffered truncation by removal of the N-terminal eight or, in some cases, nine amino acid residues. The peptide bond whose hydrolysis would remove eight residues is a typical target for the E. coli protease OmpT. We find that, by taking precautions to minimize Omp T proteolysis, or by eliminating it through mutation of the host strain, we can isolate full-length IclR protein (lacking only the N-terminal methionine residue). Full-length IclR is a much better DNA-binding protein than the truncated versions: it binds the aceBAK operator sequence 44-fold more tightly, presumably because of additional contacts that the N-terminal residues make with the DNA. Our experience thus demonstrates the advantages of using mass spectrometry to characterize newly purified proteins produced from cloned genes, especially where proteolysis or other covalent modification is a concern. This technique gives mass spectra from complex peptide mixtures that can be analyzed completely, without any fractionation of the mixtures, by reference to the amino acid sequence inferred from the base sequence of the cloned gene.

  4. Preparation and properties of pure, full-length IclR protein of Escherichia coli. Use of time-of-flight mass spectrometry to investigate the problems encountered.

    PubMed Central

    Donald, L. J.; Chernushevich, I. V.; Zhou, J.; Verentchikov, A.; Poppe-Schriemer, N.; Hosfield, D. J.; Westmore, J. B.; Ens, W.; Duckworth, H. W.; Standing, K. G.

    1996-01-01

    IclR protein, the repressor of the aceBAK operon of Escherichia coli, has been examined by time-of-flight mass spectrometry, with ionization by matrix assisted laser desorption or by electrospray. The purified protein was found to have a smaller mass than that predicted from the base sequence of the cloned iclR gene. Additional measurements were made on mixtures of peptides derived from IclR by treatment with trypsin and cyanogen bromide. They showed that the amino acid sequence is that predicted from the gene sequence, except that the protein has suffered truncation by removal of the N-terminal eight or, in some cases, nine amino acid residues. The peptide bond whose hydrolysis would remove eight residues is a typical target for the E. coli protease OmpT. We find that, by taking precautions to minimize Omp T proteolysis, or by eliminating it through mutation of the host strain, we can isolate full-length IclR protein (lacking only the N-terminal methionine residue). Full-length IclR is a much better DNA-binding protein than the truncated versions: it binds the aceBAK operator sequence 44-fold more tightly, presumably because of additional contacts that the N-terminal residues make with the DNA. Our experience thus demonstrates the advantages of using mass spectrometry to characterize newly purified proteins produced from cloned genes, especially where proteolysis or other covalent modification is a concern. This technique gives mass spectra from complex peptide mixtures that can be analyzed completely, without any fractionation of the mixtures, by reference to the amino acid sequence inferred from the base sequence of the cloned gene. PMID:8844850

  5. Charging of Proteins in Native Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Susa, Anna C.; Xia, Zijie; Tang, Henry Y. H.; Tainer, John A.; Williams, Evan R.

    2017-02-01

    Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same. Moreover, ions formed from these two solutions do not undergo proton transfer to 2-fluoropyridine, which is 8 kcal/mol more basic than ammonia. These results provide compelling evidence that proton transfer between ammonia and protein ions does not limit protein ion charge in native electrospray ionization. Both circular dichroism and ion mobility measurements indicate that there are differences in conformations of proteins in pure water and aqueous ammonium acetate, and these differences can account for the difference in the extent of charging and proton-transfer reactivities of protein ions formed from these solutions. The extent of proton transfer of the protein ions with higher gas-phase basicity bases trends with how closely the protein ions are charged to the value predicted by the Rayleigh limit for spherical water droplets approximately the same size as the proteins. These results indicate that droplet charge limits protein ion charge in native mass spectrometry and are consistent with these ions being formed by the charged residue mechanism.

  6. [Sample preparation and bioanalysis in mass spectrometry].

    PubMed

    Bourgogne, Emmanuel; Wagner, Michel

    2015-01-01

    The quantitative analysis of compounds of clinical interest of low molecular weight (<1000 Da) in biological fluids is currently in most cases performed by liquid chromatography-mass spectrometry (LC-MS). Analysis of these compounds in biological fluids (plasma, urine, saliva, hair...) is a difficult task requiring a sample preparation. Sample preparation is a crucial part of chemical/biological analysis and in a sense is considered the bottleneck of the whole analytical process. The main objectives of sample preparation are the removal of potential interferences, analyte preconcentration, and converting (if needed) the analyte into a more suitable form for detection or separation. Without chromatographic separation, endogenous compounds, co-eluted products may affect a quantitative method in mass spectrometry performance. This work focuses on three distinct parts. First, quantitative bioanalysis will be defined, different matrices and sample preparation techniques currently used in bioanalysis by mass spectrometry of/for small molecules of clinical interest in biological fluids. In a second step the goals of sample preparation will be described. Finally, in a third step, sample preparation strategies will be made either directly ("dilute and shoot") or after precipitation.

  7. Mass Spectrometry of Proteins in Liquids

    NASA Astrophysics Data System (ADS)

    Baltz-Knorr, Michelle; Papantonakis, Michael; Ermer Haglund, David, Jr.

    1999-11-01

    Infrared matrix assisted laser desorption/ionization mass spectrometry (IR-MALDI) is an effective technique for mass identification and structural analysis of biomolecules. We are using liquid glycerol/water matrices in a reflectron time-of-flight mass spectrometer equipped with a liquid nitrogen cooled sample stage to provide a more natural environment for biomolecules. An Er:YAG laser (2.94 μm) and also a tunable free electron laser (2-9 μm) are used to induce desorption and ionization by exciting the O-H and CH2 stretching vibrations in the glycerol. This vibrationally enhanced ionization makes IR-MALDI very efficient, as observed in the mass spectra of small peptides. This work is a first step toward using mass spectrometry to study noncovalently bound protein complexes in vitro and to study proteins in their cellular environment. Supported by the Medical Free Electron Laser Program of the Office of Naval Research and the Vanderbilt Molecular Biophysics Training Grant of the National Institutes of Health

  8. Toward Single-Molecule Nanomechanical Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Roukes, Michael

    2009-03-01

    Mass spectrometry (MS) has become a preeminent methodology of proteomics since it provides rapid and quantitative identification of protein species with relatively low sample consumption. Yet with the trend toward biological analysis at increasingly smaller scales, ultimately down to the volume of an individual cell, MS with few-to-single molecule resolution will be required. We report the first realization of MS based on single-biological-molecule detection with nanoelectromechanical systems (NEMS). NEMS provide unparalleled mass resolution, now sufficient for detection of individual molecular species in real time. However, high sensitivity is only one of several components required for MS. We demonstrate a first complete prototype NEMS-MS system for single-molecule mass spectrometry providing proof-of-principle for this new technique. Nanoparticles and protein species are introduced by electrospray injection from the fluid phase in ambient conditions into vacuum and subsequently delivered to the NEMS detector by hexapole ion optics . Mass measurements are then recorded in real-time as analytes adsorb, one-by-one, onto a phase-locked, ultrahigh frequency (UHF) NEMS resonator. These first NEMS-MS spectra, obtained with modest resolution from only several hundred mass adsorption events, presage the future capabilities of this methodology. We outline the substantial improvements feasible in near term, through recent advances and technological avenues that are unique to NEMS-MS.

  9. May the Best Molecule Win: Competition ESI Mass Spectrometry

    PubMed Central

    Laughlin, Sarah; Wilson, W. David

    2015-01-01

    Electrospray ionization mass spectrometry has become invaluable in the characterization of macromolecular biological systems such as nucleic acids and proteins. Recent advances in the field of mass spectrometry and the soft conditions characteristic of electrospray ionization allow for the investigation of non-covalent interactions among large biomolecules and ligands. Modulation of genetic processes through the use of small molecule inhibitors with the DNA minor groove is gaining attention as a potential therapeutic approach. In this review, we discuss the development of a competition method using electrospray ionization mass spectrometry to probe the interactions of multiple DNA sequences with libraries of minor groove binding molecules. Such an approach acts as a high-throughput screening method to determine important information including the stoichiometry, binding mode, cooperativity, and relative binding affinity. In addition to small molecule-DNA complexes, we highlight other applications in which competition mass spectrometry has been used. A competitive approach to simultaneously investigate complex interactions promises to be a powerful tool in the discovery of small molecule inhibitors with high specificity and for specific, important DNA sequences. PMID:26501262

  10. Mass spectrometry with direct supercritical fluid injection

    SciTech Connect

    Smith, R.D.; Udseth, H.R.

    1983-12-01

    Direct fluid injection mass spectrometry utilizes supercritical fluids for solvation and transfer of materials to a mass spectrometer chemical ionization (CI) source. Available data suggest that any material soluble in a supercritical fluid is transferred efficiently to the ionization region. Mass spectra are presented for mycotoxins of the trichothecene group obtained by use of supercritical carbon dioxide with isobutane as the CI reagent gas. Direct fluid injection MS/MS is also illustrated for major ions in the isobutane chemical ionization of T-2 toxin. The effect of pressure and temperature upon solubility in supercritical fluids is described and illustrated for diacetoxycirpenol. A potential method is also demonstrated for on-line fraction during MS analysis using pressure to control supercritical fluid solubility. Mass spectra are also presented for polar compounds, using supercritical ammonia, and the extension to complex mixtures is described. The fundamental basis and experimental requirements of the direct fluid injection process are discussed. 34 references, 11 figures, 1 table.

  11. Mass spectrometry with direct supercritical fluid injection

    SciTech Connect

    Smith, R.D.; Udseth, H.R.

    1983-12-01

    Direct fluid injection mass spectrometry utilizes supercritical fluids for solvation and transfer of materials to a mass spectrometer chemical ionization (CI) source. Available data suggest that any material soluble in a supercritical fluid is transferred efficiently to the ionization region. Mass spectra are presented for mycotoxins of the trichothecene group obtained by use of supercritical carbon dioxide with isobutane as the CI reagent gas. Direct fluid injection MS/MS is also illustrated for major ions in the isobutane chemical ionization of T-2 toxin. The effect of pressure and temperature upon solubility in supercritical fluids is described and illustrated for diacetoxyscirpenol. A potential method is also demonstrated for ''on-line fractionation'' during MS analysis using pressure to control supercritical fluid solubility. Mass spectra are also presented for polar compounds, using supercritical ammonia, and the extension to complex mixtures is described. The fundamental basis and experimental requirements of the direct fluid injection process are discussed. 1 figure, 11 tables.

  12. Near-infrared laser desorption/ionization aerosol mass spectrometry for investigating primary and secondary organic aerosols under low loading conditions.

    PubMed

    Geddes, Scott; Nichols, Brian; Flemer, Stevenson; Eisenhauer, Jessica; Zahardis, James; Petrucci, Giuseppe A

    2010-10-01

    A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS), is described for the real time analysis of organic aerosols at atmospherically relevant mass loadings. Use of a single NIR laser pulse to vaporize and ionize particle components deposited on an aluminum probe results in minimal fragmentation to produce exclusively intact pseudomolecular anions at [M-H](-). Limits of detection (total particulate mass sampled) for oxidized compounds of relevance to atmospheric primary and secondary organic aerosol range from 89 fg for pinic acid to 8.8 pg for cholesterol. NIR-LDI-AMS was used in conjunction with the University of Vermont Environmental Chamber to study secondary organic aerosol (SOA) formation from ozonolysis of limonene at total aerosol mass loadings ranging from 3.2 to 25.0 μg m(-3) and with a time resolution of several minutes. NIR-LDI-AMS permitted direct delineation between gas-phase, homogeneous SOA formation and subsequent heterogeneous aerosol processing by ozone.

  13. Thermal desorption/tunable vacuum-ultraviolet time-of-flight photoionization aerosol mass spectrometry for investigating secondary organic aerosols in chamber experiments.

    PubMed

    Fang, Wenzheng; Gong, Lei; Shan, Xiaobin; Liu, Fuyi; Wang, Zhenya; Sheng, Liusi

    2011-12-01

    This paper describes thermal desorption/tunable vacuum-ultraviolet photoionization time-of-flight aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for the real-time analysis of secondary organic aerosols (SOAs) in smog chamber experiments. SOAs are sampled directly from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. Once the particles have entered the source region, they impact on a heater and are vaporized. The nascent vapor is then softly ionized by tunable VUV synchrotron radiation. TD-VUV-TOF-PIAMS was used in conjunction with the smog chamber to study SOA formation from the photooxidation of toluene with hydroxyl radicals. The ionization energies (IEs) of these SOA products are sometimes very different with each other. As the ideal photon source is tunable, its energy can be adjusted for each molecular to be ionized. The mass spectra obtained at different photon energies are then to be useful for molecular identification. Real-time analysis of the mass spectra of SOAs is compared with previous off-line measurements. These results illustrate the potential of TD-VUV-TOF-PIAMS for direct molecular characterization of SOAs in smog chamber experiments.

  14. Investigation of plant hormone level changes in shoot tips of longan (Dimocarpus longan Lour.) treated with potassium chlorate by liquid chromatography-electrospray ionization mass spectrometry.

    PubMed

    Susawaengsup, Chanthana; Rayanakorn, Mongkon; Wongpornchai, Sugunya; Wangkarn, Sunanta

    2011-08-15

    The endogenous levels of indole-3-acetic acid (IAA), gibberellins (GAs), abscisic acid (ABA) and cytokinins (CKs) and their changes were investigated in shoot tips of ten longan (Dimocarpus longan Lour.) trees for off-season flowering until 60 days after potassium chlorate treatment in comparison with those of ten control (untreated) longan trees. These analytes were extracted and interfering matrices removed with a single mixed-mode solid phase extraction under optimum conditions. The recoveries at three levels of concentration were in the range of 72-112%. The endogenous plant hormones were separated and quantified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Detection limits based on the signal-to-noise ratio ranged from 10 ng mL(-1) for gibberellin A4 (GA4) to 200 ng mL(-1) for IAA. Within the first week after potassium chlorate treatment, dry weight (DW) amounts in the treated longan shoot tips of four gibberellins, namely: gibberellin A1(GA1), gibberellic acid (GA3), gibberellin A19 (GA19) and gibberellin A20 (GA20), were found to increase to approximately 25, 50, 20 and 60 ng g(-1) respectively, all of which were significantly higher than those of the controls. In contrast, gibberellin A8 (GA8) obtained from the treated longan was found to decrease to approximately 20 ng g(-1)DW while that of the control increased to around 80 ng g(-1)DW. Certain CKs which play a role in leaf bud induction, particularly isopentenyl adenine (iP), isopentenyl adenosine (iPR) and dihydrozeatin riboside (DHZR), were found to be present in amounts of approximately 20, 50 and 60 ng g(-1)DW in the shoot tips of the control longan. The analytical results obtained from the two-month off-season longan flowering period indicate that high GA1, GA3, GA19 and GA20 levels in the longan shoot tips contribute to flower bud induction while high levels of CKs, IAA and ABA in the control longan contribute more to the vegetative development.

  15. An investigation on the chemical structure of nitrogen and sulfur codoped carbon nanoparticles by ultra-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Hu, Qin; Meng, Xiangpeng; Chan, Wan

    2016-07-01

    A highly fluorescent nitrogen and sulfur codoped carbon nanoparticles (N,S-CNP) sample was obtained by microwave-assisted pyrolysis of citric acid and L-cysteine. After being purified by dialysis, the complexity and chemical composition of N,S-CNP were evaluated by ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) as well as by UPLC coupled with ultraviolet (UV) absorption and fluorescence detection (UPLC-UV/FLD) methods. By using the high-resolution UPLC separation, the N,S-CNP were well fractionated into six fractions within 3.5 min. Based on high-accuracy MS and tandem (MS/MS) analyses, the N,S-CNP species were revealed to display various chemical formulas, including (C12H16N2O7S2) n , (C9H13NO8S) n , (C18H20N2O14S2) n , (C18H20N2O12S2) n , (C9H11NO5S) n , and (C9H11NO7S) n . More importantly, our study disclosed unambiguously for the first time that the N,S-CNP species exist as supramolecular clusters with their individual monomer units linked together through noncovalent bonding forces. By using UPLC-UV/FLD analysis, the spectral characteristics of each N,S-CNP species were revealed. Each individual CNP species possesses its unique absorption and PL properties with absorption bands that are redshifted, whereas its emission bands are blueshifted with its elution order. This work highlights the merit of UPLC-MS together with UPLC-UV/FLD to investigate the chemical composition and the spectral properties of each individual N,S-CNP species. It is anticipated that our proposed methodology will open up a new venue in optimizing experimental conditions for producing specific N,S-CNP species of desired composition. Graphical Abstract Carbon nanoparticles synthesized by microwave-assisted pyrolysis of citric acid and L-cysteine exist as supramolecular clusters with their individual monomer units linked together by noncovalent interactions.

  16. Investigation of amino acid δ 13C signatures in bone collagen to reconstruct human palaeodiets using liquid chromatography-isotope ratio mass spectrometry

    NASA Astrophysics Data System (ADS)

    Choy, Kyungcheol; Smith, Colin I.; Fuller, Benjamin T.; Richards, Michael P.

    2010-11-01

    This research presents the individual amino acid δ 13C values in bone collagen of humans ( n = 9) and animals ( n = 27) from two prehistoric shell midden sites in Korea. We obtained complete baseline separation of 16 of the 18 amino acids found in bone collagen by using liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). The isotopic results reveal that the humans and animals in the two sites had similar patterns in essential amino acids (EAAs) and non-essential amino acids (NEAAs). The EAA and NEAA δ 13C values in humans are intermediate between those in marine and terrestrial animals. However, the threonine δ 13C values in humans and animals measured in this study are more highly enriched than those of other amino acids. At both sites, all amino acids in marine animals are 13C-enriched relative to those of the terrestrial animals. The isotopic evidence suggests that the Tongsamdong human had EAAs and NEAAs from marine food resources, while the Nukdo humans mainly had EAAs from terrestrial food resources but obtained NEAAs from both terrestrial and marine resources. The δ 13C isotopic differences in amino acids between marine and terrestrial animals were the largest for glycine (NEAA) and histidine (EAA) and the smallest for tyrosine (NEAA) and phenylalanine (EAA). In addition, threonine among the EAAs also had a large difference (˜8‰) in δ 13C values between marine and terrestrial animals, and has the potential to be used as an isotopic marker in palaeodietary studies. Threonine δ 13C values were used in conjunction with the established Δ 13C Glycine-phenylalanine values and produced three distinct dietary groups (terrestrial, omnivorous, and marine). In addition, threonine δ 13C values and Δ 13C Serine-phenylalanine values were discovered to separate between two dietary groups (terrestrial vs. marine), and these δ 13C values may provide a potential new indicator for investigating the distinction between marine and terrestrial protein

  17. Mass spectrometry methods for the analysis of biodegradable hybrid materials

    NASA Astrophysics Data System (ADS)

    Alalwiat, Ahlam

    This dissertation focuses on the characterization of hybrid materials and surfactant blends by using mass spectrometry (MS), tandem mass spectrometry (MS/MS), liquid chromatography (LC), and ion mobility (IM) spectrometry combined with measurement and simulation of molecular collision cross sections. Chapter II describes the principles and the history of mass spectrometry (MS) and liquid chromatography (LC). Chapter III introduces the materials and instrumentation used to complete this dissertation. In chapter IV, two hybrid materials containing poly(t-butyl acrylate) (PtBA) or poly(acrylic acid) (PAA) blocks attached to a hydrophobic peptide rich in valine and glycine (VG2), as well as the poly(acrylic acid) (PAA) and VG2 peptide precursor materials, are characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS) and ion mobility mass spectrometry (IM-MS). Collision cross-sections and molecular modeling have been used to determine the final architecture of both hybrid materials. Chapter V investigates a different hybrid material, [BMP-2(HA)2 ], comprised of a dendron with two polyethylene glycol (PEG) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone morphogenic protein mimicking peptide (BMP-2). MALDI-MS, ESI-MS and IM-MS have been used to characterize the HA and BMP-2 peptides. Collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) have been employed in double stage (i.e. tandem) mass spectrometry (MS/MS) experiments to confirm the sequences of the two peptides HA and BMP-2. The MALDI-MS, ESI-MS and IM-MS methods were also applied to characterize the [BMP-2(HA)2] hybrid material. Collision cross-section measurements and molecular modeling indicated that [BMP-2(HA)2] can attain folded or extended conformation, depending on its degree of protonation (charge state). Chapter VI focuses on the analysis of

  18. Investigation of heavy-metal accumulation in selected plant samples using laser induced breakdown spectroscopy and laser ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Galiová, M.; Kaiser, J.; Novotný, K.; Novotný, J.; Vaculovič, T.; Liška, M.; Malina, R.; Stejskal, K.; Adam, V.; Kizek, R.

    2008-12-01

    Single-pulse Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Ablation Inductively Coupled Plasma Mass-Spectrometry (LA-ICP-MS) were applied for mapping the silver and copper distribution in Helianthus Annuus L. samples treated with contaminant in controlled conditions. For Ag and Cu detection the 328.07 nm Ag(I) and 324.75 nm Cu(I) lines were used, respectively. The LIBS experimental conditions (mainly the laser energy and the observation window) were optimized in order to avoid self-absorption effect in the measured spectra. In the LA-ICP-MS analysis the Ag 107 and Cu 63 isotopes were detected. The capability of these two analytical techniques for high-resolution mapping of selected trace chemical elements was demonstrated.

  19. An Investigation of the Complexity of Maillard Reaction Product Profiles from the Thermal Reaction of Amino Acids with Sucrose Using High Resolution Mass Spectrometry

    PubMed Central

    Golon, Agnieszka; Kropf, Christian; Vockenroth, Inga; Kuhnert, Nikolai

    2014-01-01

    Thermal treatment of food changes its chemical composition drastically with the formation of “so-called” Maillard reaction products, being responsible for the sensory properties of food, along with detrimental and beneficial health effects. In this contribution, we will describe the reactivity of several amino acids, including arginine, lysine, aspartic acid, tyrosine, serine and cysteine, with carbohydrates. The analytical strategy employed involves high and ultra-high resolution mass spectrometry followed by chemometric-type data analysis. The different reactivity of amino acids towards carbohydrates has been observed with cysteine and serine, resulting in complex MS spectra with thousands of detectable reaction products. Several compounds have been tentatively identified, including caramelization reaction products, adducts of amino acids with carbohydrates, their dehydration and hydration products, disproportionation products and aromatic compounds based on molecular formula considerations. PMID:28234331

  20. Investigations into the post-translational modification and mechanism of isopenicillin N:acyl-CoA acyltransferase using electrospray mass spectrometry.

    PubMed Central

    Aplin, R T; Baldwin, J E; Roach, P L; Robinson, C V; Schofield, C J

    1993-01-01

    Electrospray mass spectrometry (e.s.m.s.) was used to confirm the position of the post-translational cleavage of the isopenicillin N:acyl-CoA acyltransferase preprotein to give the alpha- and beta-subunits. The e.s.m.s. studies suggested partial modification of the alpha-subunit in vivo by exogenously added substituted acetic acids. E.s.m.s. has also allowed the observation in vitro of the transfer of the acyl group from several acyl-CoAs to the beta-subunit. N.m.r. data for the CoA species have been deposited as Supplementary Publication SUP 500173 (2 pages) at the British Library Document Supply Centre (DSC), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, from whom copies can be obtained on the terms indicated in Biochem. J. (1993) 289, 9. Images Figure 1 PMID:8396910

  1. [Feasibility investigation of hydrogen instead of helium as carrier gas in the determination of five organophosphorus pesticides by gas chromatography-mass spectrometry].

    PubMed

    Liu, Zhenxue; Zhou, Shixue

    2015-01-01

    Helium is almost the only choosable carrier gas used in gas chromatography-mass spectrometry (GC-MS). A mixed standard solution of five organophosphorus pesticides was analyzed by using GC-MS, and hydrogen or helium as carrier gas, so as to study the feasibility of hydrogen instead of helium as carrier gas for the determination of organophosphorus pesticides. Combining a mass spectrum database built by ourselves, the results were deconvolved and identified by Automated Mass Spectral Deconvolution & Identification System (AMDIS32), a software belonging to the workstation of the instrument. Then, the statistical software, IBM SPSS Statistics 19.0 was used for the clustering analysis of the data. The results indicated that when hydrogen was used as carrier gas, the peaks of the pesticides detected were slightly earlier than those when helium used as carrier gas, but the resolutions of the chromatographic peaks were lower, and the fraction good indices (Frac. Good) were lower, too. When hydrogen was used as carrier gas, the signals of the pesticides were unstable, the measuring accuracies of the pesticides were reduced too, and even more, some compounds were undetectable. Therefore, considering the measuring accuracy, the signal stability, and the safety, etc., hydrogen should be cautiously used as carrier gas in the determination of organophosphorus pesticides by GC-MS.

  2. Investigation of NO interaction on Rh/doped TiO2-based automotive catalyst using combined transient diffuse reflectance Fourier transform infrared and mass spectrometry

    NASA Astrophysics Data System (ADS)

    Chafik, T.; Ouassini, A.; Verykios, X. E.

    1998-07-01

    The interaction of NO with Rh supported on W+6 doped TiO2 has been investigated by coupling transient diffuse reflectance Fourier transform Infrared spectroscopy and mass spectrometry. The experiments were carried out in dynamic conditions (under reactant flow and at temperature reaction) at atmospheric pressure. By comparing the results obtained with undoped Rh/TiO2 and Rh/TiO2(W6+) catalysts, the analytical approach used permitted to emphasis the effect of carrier doping, with respect to the elementary steps and surface intermediates involved in NO interaction process. It was found that W6+-doping of TiO2 promotes significantly the formation of Rh-NO- species and enhances the thermal stability of Rh-NO+ on Rh/TiO2 (W6+) surfaces. This leads to a drastic increase in the selectivity of NO decomposition reaction towards N2 formation, whereas the N2O yield decreases significantly. L'intéraction de NO sur un catalyseur à base de rhodium supporté sur TiO2 dopé par le tungstène W6+ a été étudiée en régime transitoire par couplage de la spectroscopie Infrarouge Diffuse à Transformée de Fourier (DRIFT) et la spectrométrie de masse. Ces études ont été effectuées dans des conditions dynamiques (sous flux de réactifs gazeux et à la température de la réaction) à la pression atmosphérique. La comparaison des études menées avec des catalyseurs non dopé (Rh/TiO2) et dopé (Rh/TiO2(W6+)) a permis de mettre en évidence l'influence du dopage du support catalytique sur la nature des intermédiaires superficiels et les étapes élémentaires intervenant dans le processus d'interaction de NO avec ces solides. Il a été montré que le dopage de TiO2 par W6+ accroît la formation des espèces Rh-NO- et la stabilité thermique des espèces Rh-NO+ sur Rh/TiO2(W6+). Ceci est à l'origine de l'augmentation de la sélectivité de la conversion de NO en N2 suite à la diminution considérable de la quantité N2O formée.

  3. Rapid discrimination of bacteria by paper spray mass spectrometry.

    PubMed

    Hamid, Ahmed M; Jarmusch, Alan K; Pirro, Valentina; Pincus, David H; Clay, Bradford G; Gervasi, Gaspard; Cooks, R Graham

    2014-08-05

    Paper spray mass spectrometry ambient ionization is utilized for rapid discrimination of bacteria without sample preparation. Bacterial colonies were smeared onto filter paper precut to a sharp point, then wetted with solvent and held at a high potential. Charged droplets released by field emission were sucked into the mass spectrometer inlet and mass spectra were recorded. Sixteen different species representing eight different genera from Gram-positive and Gram-negative bacteria were investigated. Phospholipids were the predominant species observed in the mass spectra in both the negative and positive ion modes. Multivariate data analysis based on principal component analysis, followed by linear discriminant analysis, allowed bacterial discrimination. The lipid information in the negative ion mass spectra proved useful for species level differentiation of the investigated Gram-positive bacteria. Gram-negative bacteria were differentiated at the species level by using a numerical data fusion strategy of positive and negative ion mass spectra.

  4. Noncovalent interactions between ([18]crown-6)-tetracarboxylic acid and amino acids: electrospray-ionization mass spectrometry investigation of the chiral-recognition processes.

    PubMed

    Gerbaux, Pascal; De Winter, Julien; Cornil, David; Ravicini, Katia; Pesesse, Gaëlle; Cornil, Jérôme; Flammang, Robert

    2008-01-01

    Chiral recognition of enantiomers by host compounds is one of the most challenging topics in modern host-guest chemistry. Amongst the well-established methods, mass spectrometry (MS) is increasingly used nowadays, due to its low detection limit, short analysis time, and suitability for analyzing mixtures and for studying chiral effects in the gas phase. The development of electrospray-ionization (ESI) techniques provides an invaluable tool to study, in the gas phase, diastereoisomeric complex ions prepared from enantiomer ions and a chiral selector. This paper reports on an ESIMS and ESIMSMS study of the molecular mechanisms that intervene in the chiral-recognition phenomena observed between amino acids and a chiral crown ether. The modified crown ether, namely (+)-([18]crown-6)-2,3,11,12-tetracarboxylic acid, is used as the chiral selector when covalently bound on a stationary phase in liquid chromatography. This study was stimulated by the fact that, except with threonine and proline, consistent elution orders were observed, which indicates that the D enantiomers interact more strongly with the chiral selector than the L enantiomers. For proline, the lack of a primary amino group is likely to be responsible for the nonresolution of the two forms, whereas the second stereogenic center on threonine could explain the reversed elution order. In light of those observations, we performed mass spectrometry experiments to understand more deeply the enantiomeric recognition phenomena, both in solution by the enantiomer-labeled guest method and in the gas phase by gas-phase ligand-exchange ion/molecule reactions. The results have been further supported by quantum chemical calculations. One of the most interesting features of this work is the identification of a nonspecific interaction between proline and the crown ether upon ESIMS analysis.

  5. Analysis of Glycosaminoglycans Using Mass Spectrometry

    PubMed Central

    Staples, Gregory O.; Zaia, Joseph

    2015-01-01

    The glycosaminoglycans (GAGs) are linear polysaccharides expressed on animal cell surfaces and in extracellular matrices. Their biosynthesis is under complex control and confers a domain structure that is essential to their ability to bind to protein partners. Key to understanding the functions of GAGs are methods to determine accurately and rapidly patterns of sulfation, acetylation and uronic acid epimerization that correlate with protein binding or other biological activities. Mass spectrometry (MS) is particularly suitable for the analysis of GAGs for biomedical purposes. Using modern ionization techniques it is possible to accurately determine molecular weights of GAG oligosaccharides and their distributions within a mixture. Methods for direct interfacing with liquid chromatography have been developed to permit online mass spectrometric analysis of GAGs. New tandem mass spectrometric methods for fine structure determination of GAGs are emerging. This review summarizes MS-based approaches for analysis of GAGs, including tissue extraction and chromatographic methods compatible with LC/MS and tandem MS. PMID:25705143

  6. Computational mass spectrometry for small molecules

    PubMed Central

    2013-01-01

    The identification of small molecules from mass spectrometry (MS) data remains a major challenge in the interpretation of MS data. This review covers the computational aspects of identifying small molecules, from the identification of a compound searching a reference spectral library, to the structural elucidation of unknowns. In detail, we describe the basic principles and pitfalls of searching mass spectral reference libraries. Determining the molecular formula of the compound can serve as a basis for subsequent structural elucidation; consequently, we cover different methods for molecular formula identification, focussing on isotope pattern analysis. We then discuss automated methods to deal with mass spectra of compounds that are not present in spectral libraries, and provide an insight into de novo analysis of fragmentation spectra using fragmentation trees. In addition, this review shortly covers the reconstruction of metabolic networks using MS data. Finally, we list available software for different steps of the analysis pipeline. PMID:23453222

  7. Computational mass spectrometry for small molecules.

    PubMed

    Scheubert, Kerstin; Hufsky, Franziska; Böcker, Sebastian

    2013-03-01

    : The identification of small molecules from mass spectrometry (MS) data remains a major challenge in the interpretation of MS data. This review covers the computational aspects of identifying small molecules, from the identification of a compound searching a reference spectral library, to the structural elucidation of unknowns. In detail, we describe the basic principles and pitfalls of searching mass spectral reference libraries. Determining the molecular formula of the compound can serve as a basis for subsequent structural elucidation; consequently, we cover different methods for molecular formula identification, focussing on isotope pattern analysis. We then discuss automated methods to deal with mass spectra of compounds that are not present in spectral libraries, and provide an insight into de novo analysis of fragmentation spectra using fragmentation trees. In addition, this review shortly covers the reconstruction of metabolic networks using MS data. Finally, we list available software for different steps of the analysis pipeline.

  8. CHARACTERIZATION OF CRYPTOSPORIDIUM PARVUM BY MATRIX-ASSISTED LASER DESORPTION -- IONIZATION TIME OF FLIGHT MASS SPECTROMETRY

    EPA Science Inventory

    Matrix assisted laser desorption/ionization (MALDI) mass spectrometry was used to investigate whole and freeze thawed Cryptosporidium parvum oocysts. Whole oocysts revealed some mass spectral features. Reproducible patterns of spectral markers and increased sensitivity were obtai...

  9. Improving gene annotation using peptide mass spectrometry

    PubMed Central

    Tanner, Stephen; Shen, Zhouxin; Ng, Julio; Florea, Liliana; Guigó, Roderic; Briggs, Steven P.; Bafna, Vineet

    2007-01-01

    Annotation of protein-coding genes is a key goal of genome sequencing projects. In spite of tremendous recent advances in computational gene finding, comprehensive annotation remains a challenge. Peptide mass spectrometry is a powerful tool for researching the dynamic proteome and suggests an attractive approach to discover and validate protein-coding genes. We present algorithms to construct and efficiently search spectra against a genomic database, with no prior knowledge of encoded proteins. By searching a corpus of 18.5 million tandem mass spectra (MS/MS) from human proteomic samples, we validate 39,000 exons and 11,000 introns at the level of translation. We present translation-level evidence for novel or extended exons in 16 genes, confirm translation of 224 hypothetical proteins, and discover or confirm over 40 alternative splicing events. Polymorphisms are efficiently encoded in our database, allowing us to observe variant alleles for 308 coding SNPs. Finally, we demonstrate the use of mass spectrometry to improve automated gene prediction, adding 800 correct exons to our predictions using a simple rescoring strategy. Our results demonstrate that proteomic profiling should play a role in any genome sequencing project. PMID:17189379

  10. The role of ion mobility spectrometry-mass spectrometry in the analysis of protein reference standards.

    PubMed

    Pritchard, Caroline; O'Connor, Gavin; Ashcroft, Alison E

    2013-08-06

    To achieve comparability of measurement results of protein amount of substance content between clinical laboratories, suitable reference materials are required. The impact on measurement comparability of potential differences in the tertiary and quaternary structure of protein reference standards is as yet not well understood. With the use of human growth hormone as a model protein, the potential of ion mobility spectrometry-mass spectrometry as a tool to assess differences in the structure of protein reference materials and their interactions with antibodies has been investigated here.

  11. Biological accelerator mass spectrometry at Uppsala University.

    PubMed

    Salehpour, Mehran; Possnert, Göran; Bryhni, Helge; Palminger-Hallén, Ira; Ståhle, Lars

    2009-03-01

    A new research programme for the biological applications of accelerator mass spectrometry has been initiated at Uppsala University and the first results are presented. A (14)C-labelled pharmaceutical substance has been dissolved in human blood, plasma and urine and diluted over 3 orders of magnitude. The measured drug concentrations were found to be in good agreement with the predicted values. Furthermore, the effect of the sample preparation background contribution has been studied as the sample amount was varied down to sub-microl sizes.

  12. Accelerator mass spectrometry of the planetary elements

    NASA Astrophysics Data System (ADS)

    Fifield, L. K.; Clacher, A. P.; Morris, K.; King, S. J.; Cresswell, R. G.; Day, J. P.; Livens, F. R.

    1997-03-01

    Accelerator mass spectrometry has been applied for the first time to the detection of 237Np. Sensitivity approaches 105 atoms. A first measurement of the mobility of 237Np in a marine environment is reported, and lends support to the prediction that neptunium should be substantially more mobile than plutonium. Measurements of backgrounds and transmissions for plutonium and neptunium in different charge states are also reported. In addition, the relative negative ion formation probabilities for the monoxide ions of Th, U, Np and Pu have been measured.

  13. Isotopic trace analysis by atomic mass spectrometry

    SciTech Connect

    Stoffels, J.J.

    1993-12-01

    All the production facilities at Hanford are now shut down. However, the legacy from half a century of plutonium production includes 177 underground storage tanks of up to one million gallons each containing the largest accumulation of high-level radioactive waste in what used to be called ``the free world.`` Hanford`s new mission, in addition to a spectrum of ongoing research and development, is radioactive waste management and environmental restoration. Isotope-ratio mass spectrometry will continue to be an essential tool in monitoring the progress of that mission.

  14. Mass Determination of Entire Amyloid Fibrils by Using Mass Spectrometry.

    PubMed

    Doussineau, Tristan; Mathevon, Carole; Altamura, Lucie; Vendrely, Charlotte; Dugourd, Philippe; Forge, Vincent; Antoine, Rodolphe

    2016-02-12

    Amyloid fibrils are self-assembled protein structures with important roles in biology (either pathogenic or physiological), and are attracting increasing interest in nanotechnology. However, because of their high aspect ratio and the presence of some polymorphism, that is, the possibility to adopt various structures, their characterization is challenging and basic information such as their mass is unknown. Here we show that charge-detection mass spectrometry, recently developed for large self-assembled systems such as viruses, provides such information in a straightforward manner. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Resonant Laser Ionization Mass Spectrometry: An Alternative to AMS?

    SciTech Connect

    Wendt, Klaus; Trautmann, N.; Bushaw, Bruce A.

    2001-02-15

    Resonant laser ionization mass spectrometry (RIMS) has developed into a versatile experimental method particularly concerning applications for highly selective ultratrace analaysis. Apart from providing nearly complete isobaric suspression and high overall efficiency, the possibolility for combining optical isotpic selectivity with that of hte mass spectrometer leads to remarkable specifications. The widespread analytical potential and applicability of different techniques based on resonant laser ionization is demonstrated in investigations on stable and radioactive ultratrace isotopes with the focus on applications which require high selectivity, concerning, e.g., the noble gas isotopes, 81,85KR, PU isotopes, 89,90SR, 99Tc and 41Ca. Selective ultratrace determination of these radioisotopes proved access to a variety of fundamental research problems in environmental sciences, geo- and cosmochemistry, archaeology, and biomedicine, which previously were often an exclusive domain for accelerator mass spectrometry (AMS).

  16. Recent developments in Penning-trap mass spectrometry

    NASA Astrophysics Data System (ADS)

    Block, M.

    2016-06-01

    Penning-trap mass spectrometry provides atomic masses with the highest precision. At accelerator-based on-line facilities it is applied to investigate exotic radionuclides in the context of tests of fundamental symmetries, nuclear structure studies, and nuclear astrophysics research. Recent progress in slowing down radioactive ion-beams in buffer-gas cells in combination with advanced ion-manipulation techniques has paved the way to reach nuclides ever-more far from stability. In this endeavor many efforts are underway to increase the sensitivity, the efficiency, and the precision of Penning-trap mass spectrometry. In this article some recent experimental developments are addressed with the focus on the phase-imaging ion-cyclotron-resonance technique and the Fourier transform ion-cyclotron-resonance technique.

  17. Boundaries of Mass Resolution in Native Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lössl, Philip; Snijder, Joost; Heck, Albert J. R.

    2014-06-01

    Over the last two decades, native mass spectrometry (MS) has emerged as a valuable tool to study intact proteins and noncovalent protein complexes. Studied experimental systems range from small-molecule (drug)-protein interactions, to nanomachineries such as the proteasome and ribosome, to even virus assembly. In native MS, ions attain high m/z values, requiring special mass analyzers for their detection. Depending on the particular mass analyzer used, instrumental mass resolution does often decrease at higher m/z but can still be above a couple of thousand at m/z 5000. However, the mass resolving power obtained on charge states of protein complexes in this m/z region is experimentally found to remain well below the inherent instrument resolution of the mass analyzers employed. Here, we inquire into reasons for this discrepancy and ask how native MS would benefit from higher instrumental mass resolution. To answer this question, we discuss advantages and shortcomings of mass analyzers used to study intact biomolecules and biomolecular complexes in their native state, and we review which other factors determine mass resolving power in native MS analyses. Recent examples from the literature are given to illustrate the current status and limitations.

  18. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery

    PubMed Central

    Lu, Ming; Faull, Kym F.; Whitelegge, Julian P.; He, Jianbo; Shen, Dejun; Saxton, Romaine E.; Chang, Helena R.

    2007-01-01

    Proteomics is a rapidly advancing field not only in the field of biology but also in translational cancer research. In recent years, mass spectrometry and associated technologies have been explored to identify proteins or a set of proteins specific to a given disease, for the purpose of disease detection and diagnosis. Such biomarkers are being investigated in samples including cells, tissues, serum/plasma, and other types of body fluids. When sufficiently refined, proteomic technologies may pave the way for early detection of cancer or individualized therapy for cancer. Mass spectrometry approaches coupled with bioinformatic tools are being developed for biomarker discovery and validation. Understanding basic concepts and application of such technology by investigators in the field may accelerate the clinical application of protein biomarkers in disease management. PMID:19662217

  19. Mass Spectrometry for Rapid Characterization of Microorganisms

    NASA Astrophysics Data System (ADS)

    Demirev, Plamen A.; Fenselau, Catherine

    2008-07-01

    Advances in instrumentation, proteomics, and bioinformatics have contributed to the successful applications of mass spectrometry (MS) for detection, identification, and classification of microorganisms. These MS applications are based on the detection of organism-specific biomarker molecules, which allow differentiation between organisms to be made. Intact proteins, their proteolytic peptides, and nonribosomal peptides have been successfully utilized as biomarkers. Sequence-specific fragments for biomarkers are generated by tandem MS of intact proteins or proteolytic peptides, obtained after, for instance, microwave-assisted acid hydrolysis. In combination with proteome database searching, individual biomarker proteins are unambiguously identified from their tandem mass spectra, and from there the source microorganism is also identified. Such top-down or bottom-up proteomics approaches permit rapid, sensitive, and confident characterization of individual microorganisms in mixtures and are reviewed here. Examples of MS-based functional assays for detection of targeted microorganisms, e.g., Bacillus anthracis, in environmental or clinically relevant backgrounds are also reviewed.

  20. Liquid Chromatography Mass Spectrometry Profiling of Histones

    PubMed Central

    Su, Xiaodan; Jacob, Naduparambil K.; Amunugama, Ravindra; Lucas, David M.; Knapp, Amy R.; Ren, Chen; Davis, Melanie E.; Marcucci, Guido; Parthun, Mark R.; Byrd, John C.; Fishel, Richard A.; Freitas, Michael A.

    2007-01-01

    Here we describe the use of reverse-phase liquid chromatography mass spectrometry (RP-LC-MS) to simultaneously characterize variants and post-translationally modified isoforms for each histone. The analysis of intact proteins significantly reduces the time of sample preparation and simplifies data interpretation. LC-MS analysis and peptide mass mapping have previously been applied to identify histone proteins and to characterize their post-translational modifications. However, these studies provided limited characterization of both linker histones and core histones. The current LC-MS analysis allows for the simultaneous observation of all histone PTMs and variants (both replacement and bulk histones) without further enrichment, which will be valuable in comparative studies. Protein identities were verified by the analysis of histone H2A species using RPLC fractionation, AU-PAGE separation and nano-LC-MS/MS. PMID:17254850

  1. Study of odor recorder using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Miura, Tomohiro; Nakamoto, Takamichi; Moriizumi, Toyosaka

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

  2. FAPA mass spectrometry of designer drugs.

    PubMed

    Smoluch, Marek; Gierczyk, Blazej; Reszke, Edward; Babij, Michal; Gotszalk, Teodor; Schroeder, Grzegorz; Silberring, Jerzy

    2016-01-01

    Application of a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS) for the analysis of designer drugs is described. In this paper, we present application of FAPA MS for identification of exemplary psychotropic drugs: JWH-122, 4BMC, Pentedrone, 3,4-DNNC and ETH-CAT. We have utilized two approaches for introducing samples into the plasma stream; first in the form of a methanolic aerosol from the nebulizer, and the second based on a release of vapors from the electrically heated crucible by thermal desorption. The analytes were ionized by FAPA and identified in the mass analyzer. The order of release of the compounds depends on their volatility. These methods offer fast and reliable structural information, without pre-separation, and can be an alternative to the Electron Impact, GC/MS, and ESI for fast analysis of designer-, and other psychoactive drugs.

  3. MALDI mass spectrometry imaging in rheumatic diseases.

    PubMed

    Rocha, Beatriz; Cillero-Pastor, Berta; Blanco, Francisco J; Ruiz-Romero, Cristina

    2017-07-01

    Mass spectrometry imaging (MSI) is a technique used to visualize the spatial distribution of biomolecules such as peptides, proteins, lipids or other organic compounds by their molecular masses. Among the different MSI strategies, MALDI-MSI provides a sensitive and label-free approach for imaging of a wide variety of protein or peptide biomarkers from the surface of tissue sections, being currently used in an increasing number of biomedical applications such as biomarker discovery and tissue classification. In the field of rheumatology, MALDI-MSI has been applied to date for the analysis of joint tissues such as synovial membrane or cartilage. This review summarizes the studies and key achievements obtained using MALDI-MSI to increase understanding on rheumatic pathologies and to describe potential diagnostic or prognostic biomarkers of these diseases. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Steroid Hormone Analysis by Tandem Mass Spectrometry

    PubMed Central

    Soldin, Steven J.; Soldin, Offie P.

    2013-01-01

    BACKGROUND New high-performance liquid chromatography/ tandem mass spectrometry (LC-MS/MS) methods are among the most successful approaches to improve specificity problems inherent in many immunoassays. CONTENT We emphasize problems with immunoassays for the measurement of steroids and review the emerging role of LC-MS/MS in the measurement of clinically relevant steroids. The latest generation of tandem mass spectrometers has superior limits of quantification, permitting omission of previously employed derivatization steps. The measurement of steroid profiles in the diagnosis and treatment of congenital adrenal hyperplasia, adrenal insufficiency, chronic pelvic pain and prostatitis, oncology (breast cancer), and athletes has important new applications. CONCLUSIONS LC-MS/MS now affords the specificity, imprecision, and limits of quantification necessary for the reliable measurement of steroids in human fluids, enhancing diagnostic capabilities, particularly when steroid profiles are available. PMID:19325015

  5. Radiocarbon positive-ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Shanks, Richard P.; Donzel, Xavier; Gaubert, Gabriel

    2015-10-01

    Proof-of-principle of a new mass spectrometric technique for radiocarbon measurement is demonstrated. Interfering nitrogen and hydrocarbon molecules are largely eliminated in a charge-exchange cell operating on non-metallic gas. The positive-to-negative ion conversion is the reverse of that conventionally used in accelerator mass spectrometry (AMS) and is compatible with plasma ion sources that may be significantly more efficient and capable of greater output than are AMS sputter ion sources. The Nanogan electron cyclotron resonance (ECR) ion source employed exhibited no sample memory and the >50 kyrs age range of AMS was reproduced. A bespoke prototype new instrument is now required to optimise the plasma and cell physics and to realise hypothetical performance gains over AMS.

  6. [Mass spectrometry in the clinical microbiology laboratory].

    PubMed

    Jordana-Lluch, Elena; Martró Català, Elisa; Ausina Ruiz, Vicente

    2012-12-01

    Infectious diseases are still a cause of high mortality and morbidity rates. Current microbiological diagnostic methods are based on culture and phenotypic identification of isolated microorganisms, which can be obtained in about 24-48 h. Given that the microbiological identification is of major importance for patient management, new diagnostic methods are needed in order to detect and identify microorganisms in a timely and accurate manner. Over the last few years, several molecular techniques based on the amplification of microbial nucleic acids have been developed with the aim of reducing the time needed for the identification of the microorganisms involved in different infectious processes. On the other hand, mass spectrometry has emerged as a rapid and consistent alternative to conventional methods for microorganism identification. This review describes the most widely used mass spectrometry technologies -matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and electrospray ionization time-of-flight (ESI-TOF)-, both for protein and nucleic acid analysis, as well as the commercial platforms available. Related publications of most interest in clinical microbiology are also reviewed.

  7. Research Using Accelerator Mass Spectrometry at Arizona

    NASA Astrophysics Data System (ADS)

    Jull, A.; Donahue, D. J.; Burr, G. S.; Beck, W.; Hatheway, A. L.; Biddulph, D. L.; McHargue, L. R.

    2002-12-01

    An Accelerator Mass Spectrometry (AMS) facility has been operated at the University of Arizona since 1982. This is an excellent example of a facility which has benefitted from the NSF Earth Sciences Instrumentation and Facilities Program. AMS has many applications to the fields of geochronology, geoarchaeology, paleoclimatology. A wide range of climatic, geologic and archeological records can be characterized by measuring their 14C and 10Be concentrations, using accelerator mass spectrometry (AMS). These records are found not only in the traditional sampling sites such as lake sediments and ice cores, but also in diverse natural accumulates and biogeochemical products such as: loess/paleosol deposits, corals, speleothems, and forest-fire horizons. The in-situ production of cosmogenic radionuclides in terrestrial and extraterrestrial materials provides several possibilities of determining their chronology. Thes studies are important for understanding cosmic-ray production of radionuclides in rock surfaces, by which we can draw conclusions about exposure time and erosion. Studies on extraterrestrial materials such as lunar samples allow us to determine the solar and galactic cosmic-ray fluxes in the past, and the cosmogenic 14C and 10Be in meteorites can be used to determine terrestrial ages. In this paper, we will highlight some selected applications of AMS, including dating of some interesting art works and artifacts, to show some of the great range of studies which can be undertaken.

  8. Lipid imaging by mass spectrometry - a review.

    PubMed

    Gode, David; Volmer, Dietrich A

    2013-03-07

    Mass spectrometry imaging (MSI) has proven to be extremely useful for applications such as the spatial analysis of peptides and proteins in biological tissue, the performance assessment of drugs in vivo or the measurement of protein or metabolite expression as tissue classifiers or biomarkers from disease versus control tissue comparisons. The most popular MSI technique is MALDI mass spectrometry. First invented by Richard Caprioli in the mid-1990s, it is the highest performing MSI technique in terms of spatial resolution, sensitivity for intact biomolecules and application range today. The unique ability to identify and spatially resolve numerous compounds simultaneously, based on m/z values has inter alia been applied to untargeted and targeted chemical mapping of biological compartments, revealing changes of physiological states, disease pathologies and metabolic faith and distribution of xenobiotics. Many MSI applications focus on lipid species because of the lipids' diverse roles as structural components of cell membranes, their function in the surfactant cycle, and their involvement as second messengers in signalling cascades of tissues and cells. This article gives a comprehensive overview of lipid imaging techniques and applications using established MALDI and SIMS methods but also other promising MSI techniques such as DESI.

  9. [Application of mass spectrometry in mycobacteria].

    PubMed

    Alcaide, Fernando; Palop-Borrás, Begoña; Domingo, Diego; Tudó, Griselda

    2016-06-01

    To date, more than 170 species of mycobacteria have been described, of which more than one third may be pathogenic to humans, representing a significant workload for microbiology laboratories. These species must be identified in clinical practice, which has long been a major problem due to the shortcomings of conventional (phenotypic) methods and the limitations and complexity of modern methods largely based on molecular biology techniques. The aim of this review was to briefly describe different aspects related to the use of MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) for the identification of mycobacteria. Several difficulties are encountered with the use of this methodology in these microorganisms mainly due to the high pathogenicity of some mycobacteria and the peculiar structure of their cell wall, requiring inactivation and special protein extraction protocols. We also analysed other relevant aspects such as culture media, the reference methods employed (gold standard) in the final identification of the different species, the cut-off used to accept data as valid, and the databases of the different mass spectrometry systems available. MS has revolutionized diagnosis in modern microbiology; however, specific improvements are needed to consolidate the use of this technology in mycobacteriology. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  10. Isotope ratio mass spectrometry in nutrition research

    SciTech Connect

    Luke, A.H.

    1994-12-31

    Many of the biochemical pathways and processes that form the foundation of modern nutrition research was elucidated using stable isotopes as physiological tracers. Since the discovery of stable isotopes, improvements and innovations in mass spectrometry and chromatography have led to greatly expanded applications. This research project was designed to evaluate gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) as a tool for isotopic tracer studies and to delineate the operational parameters for the analysis of {sup 13}C-labeled cholesterol, leucine and {alpha}-ketoisocaproate. The same isotope ratio mass spectrometer was then used as the base instrument for the ratio mass spectrometer was then used as the base instrument for the development of two additional inlet systems: a continuous-flow inlet for the analyses of {sup 13}C and {sup 18}O as CO{sub 2} and a filament inlet for on-line combustion and isotopic analysis of non-volatile organic compounds. Each of these three inlets was evaluated and their utility in nutrition research illustrated. GC/C/IRMS was used to analyze cholesterol, leucine and {alpha}-ketoisocaproate with good accuracy, precision and little isotopic memory. For all three compounds the detection limits achieved well surpassed currently used technologies. For compounds that can be well separated by GC, GC/C/IRMS is a valuable analytical tool. The continuous-flow inlet provided good accuracy and precision for measurements of {sup 13}CO{sub 2} from breath tests and {sup 18}O as CO{sub 2} from total energy expenditure tests. Most importantly, the continuous-flow inlet increased sample throughput by at least a factor of three over conventional analytical techniques. The filament inlet provided accurate and precise {sup 13}C ratio measurements of both natural abundance and enriched standards of non-volatile organic compounds of physiological interest.

  11. Isotope ratio analysis by Orbitrap mass spectrometry

    NASA Astrophysics Data System (ADS)

    Eiler, J. M.; Chimiak, L. M.; Dallas, B.; Griep-Raming, J.; Juchelka, D.; Makarov, A.; Schwieters, J. B.

    2016-12-01

    Several technologies are being developed to examine the intramolecular isotopic structures of molecules (i.e., site-specific and multiple substitution), but various limitations in sample size and type or (for IRMS) resolution have so far prevented the creation of a truly general technique. We will discuss the initial findings of a technique based on Fourier transform mass spectrometry, using the Thermo Scientific Q Exactive GC — an instrument that contains an Orbitrap mass analyzer. Fourier transform mass spectrometry is marked by exceptionally high mass resolutions (the Orbitrap reaches M/∆M in the range 250,000-1M in the mass range of greatest interest, 50-200 amu). This allows for resolution of a large range of nearly isobaric interferences for isotopologues of volatile and semi-volatile compounds (i.e., involving isotopes of H, C, N, O and S). It also provides potential to solve very challenging mass resolution problems for isotopic analysis of other, heavier elements. Both internal and external experimental reproducibilities of isotope ratio analyses using the Orbitrap typically conform to shot-noise limits down to levels of 0.2 ‰ (1SE), and routinely in the range 0.5-1.0 ‰, with similar accuracy when standardized to concurrently run reference materials. Such measurements can be made without modifications to the ion optics of the Q Exactive GC, but do require specially designed sample introduction devices to permit sample/standard comparison and long integration times. The sensitivity of the Q Exactive GC permits analysis of sub-nanomolar samples and quantification of multiply-substituted species. The site-specific capability of this instrument arises from the fact that mass spectra of molecular analytes commonly contain diverse fragment ion species, each of which samples a specific sub-set of molecular sites. We will present applications of this technique to the biological and abiological chemistry of amino acids, forensic identification of

  12. NITPICK: peak identification for mass spectrometry data

    PubMed Central

    Renard, Bernhard Y; Kirchner, Marc; Steen , Hanno; Steen, Judith AJ; Hamprecht , Fred A

    2008-01-01

    Background The reliable extraction of features from mass spectra is a fundamental step in the automated analysis of proteomic mass spectrometry (MS) experiments. Results This contribution proposes a sparse template regression approach to peak picking called NITPICK. NITPICK is a Non-greedy, Iterative Template-based peak PICKer that deconvolves complex overlapping isotope distributions in multicomponent mass spectra. NITPICK is based on fractional averagine, a novel extension to Senko's well-known averagine model, and on a modified version of sparse, non-negative least angle regression, for which a suitable, statistically motivated early stopping criterion has been derived. The strength of NITPICK is the deconvolution of overlapping mixture mass spectra. Conclusion Extensive comparative evaluation has been carried out and results are provided for simulated and real-world data sets. NITPICK outperforms pepex, to date the only alternate, publicly available, non-greedy feature extraction routine. NITPICK is available as software package for the R programming language and can be downloaded from . PMID:18755032

  13. Reliable liquid chromatography-mass spectrometry method for investigation of primary aromatic amines migration from food packaging and during industrial curing of multilayer plastic laminates.

    PubMed

    Lambertini, Francesca; Di Lallo, Valentina; Catellani, Dante; Mattarozzi, Monica; Careri, Maria; Suman, Michele

    2014-09-01

    Primary aromatic amines (PAAs) can migrate from packaging into food from different sources such as polyurethanic adhesives used for the manufacture of multilayer films, which may contain residual aromatic isocyanates, or recycled paperboard, because of the presence of azo dyes in the printed paper massively used in the recycling process. In the present work, a reliable analytical method, exploiting a conventional high-performance liquid chromatography-(selected ion monitoring)-mass spectrometry system, for PAAs compliance assessment in food contact materials was developed as an effective alternative to the current standard spectrophotometric one, moving in this way from the screening to the accurate and selective quantitation perspective for the analysis of PAAs both in aqueous and acidic food simulants. The main validation parameters were verified achieving very satisfactory results in terms of linearity range, limit of detection (ranging from 0.1 to 1.0 µg kg(-1)) and quantitation (ranging from 0.1 to 3.6 µg kg(-1)), repeatability and accuracy. Suitability of the method was demonstrated for a wide range of commercial samples, chosen among different producers of the most common used food packaging plastic and paperboard categories and then analyzed to assess the risk related to PAAs migration. Finally, the method was also successfully exploited to monitor the evolution of potential PAAs migration during the industrial curing process of multilayer plastic laminates, prior to their release for delivery to the food industry end user. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Investigation of colloidal graphite as a matrix for matrix-assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes.

    PubMed

    Warren, Alexander D; Conway, Ulric; Arthur, Christopher J; Gates, Paul J

    2016-07-01

    The analysis of low molecular weight compounds by matrix-assisted laser desorption/ionisation mass spectrometry is problematic due to the interference and suppression of analyte ionisation by the matrices typically employed - which are themselves low molecular weight compounds. The application of colloidal graphite is demonstrated here as an easy to use matrix that can promote the ionisation of a wide range of analytes including low molecular weight organic compounds, complex natural products and inorganic complexes. Analyte ionisation with colloidal graphite is compared with traditional organic matrices along with various other sources of graphite (e.g. graphite rods and charcoal pencils). Factors such as ease of application, spectra reproducibility, spot longevity, spot-to-spot reproducibility and spot homogeneity (through single spot imaging) are explored. For some analytes, considerable matrix suppression effects are observed resulting in spectra completely devoid of matrix ions. We also report the observation of radical molecular ions [M(-●) ] in the negative ion mode, particularly with some aromatic analytes. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Investigation of natural phosphatidylcholine sources: separation and identification by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2) of molecular species.

    PubMed

    Le Grandois, Julie; Marchioni, Eric; Zhao, Minjie; Giuffrida, Francesca; Ennahar, Saïd; Bindler, Françoise

    2009-07-22

    This study is a contribution to the exploration of natural phospholipid (PL) sources rich in long-chain polyunsaturated fatty acids (LC-PUFAs) with nutritional interest. Phosphatidylcholines (PCs) were purified from total lipid extracts of different food matrices, and their molecular species were separated and identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS(2)). Fragmentation of lithiated adducts allowed for the identification of fatty acids linked to the glycerol backbone. Soy PC was particularly rich in species containing essential fatty acids, such as (18:2-18:2)PC (34.0%), (16:0-18:2)PC (20.8%), and (18:1-18:2)PC (16.3%). PC from animal sources (ox liver and egg yolk) contained major molecular species, such as (16:0-18:2)PC, (16:0-18:1)PC, (18:0-18:2)PC, or (18:0-18:1)PC. Finally, marine source (krill oil), which was particularly rich in (16:0-20:5)PC and (16:0-22:6)PC, appeared to be an interesting potential source for food supplementation with LC-PUFA-PLs, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

  16. Quantitative profiling of PrP(Sc) peptides by high-performance liquid chromatography mass spectrometry to investigate the diversity of prions.

    PubMed

    Gielbert, Adriana; Davis, Linda A; Sayers, A Robin; Tang, Yue; Hope, James; Sauer, Maurice J

    2013-05-01

    Prions are proteins that can exist in two (or more) folding states, a normal or cellular form and a series of infectious or prion forms, which are prone to aggregate. The prion form can induce conversion of the cellular form and so transmit phenotypic effects of this structural rearrangement within and between cells and organisms. The conversion of PrP(C), the mammalian prion glycoprotein, to its prion form, PrP(Sc), in the brain is a precursor to progressive neurological degeneration, and the various folded forms of PrP(Sc) (defined by the size and glycosylation of protease-resistant core peptides of the PrP aggregates, PrP(res)) are characteristic of a particular neurodegenerative phenotype or prion disease. Here, quantitative multiplex mass spectrometry was used for N-terminal amino acid profiling (N-TAAP) of PrP(res) from sheep affected by scrapie, the prion disease of small ruminants, to rapidly assess the diversity of prions within particular flocks. In 29 cases, PrP(res) concentrations varied from below the limit of detection (350 fmol/g) to 15 pmol/g wet brain. Although most had a single N-TAAP profile, two novel variants were identified: one common to the ARH/ARQ animals in this study and one in an animal of the wild-type sheep PrP genotype (ARQ/ARQ).

  17. Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry To Identify Vancomycin-Resistant Enterococci and Investigate the Epidemiology of an Outbreak

    PubMed Central

    Price, Gareth R.; Schooneveldt, Jacqueline M.; Schlebusch, Sanmarié; Tilse, Martyn H.; Urbanski, Tess; Hamilton, Brett; Venter, Deon

    2012-01-01

    The control of vancomycin-resistant enterococci (VRE) has become an increasing burden on health care resources since their discovery over 20 years ago. Current techniques employed for their detection include time-consuming and laborious phenotypic methods or molecular methods requiring costly equipment and consumables and highly trained staff. An accurate, rapid diagnostic test has the ability to greatly reduce the spread of this organism, which has the ability to colonize patients for long periods, potentially even lifelong. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a technology with the ability to identify organisms in seconds and has shown promise in the identification of other forms of antimicrobial resistance in other organisms. Here we show that MALDI-TOF MS is capable of rapidly and accurately identifying vanB-positive Enterococcus faecium VRE from susceptible isolates. Internal validation of the optimal model generated produced a sensitivity of 92.4% and a specificity of 85.2%. Prospective validation results, following incorporation into the routine laboratory work flow, demonstrated a greater sensitivity and specificity at 96.7% and 98.1%, respectively. In addition, the utilization of MALDI-TOF MS to determine the relatedness of isolates contributing to an outbreak is also demonstrated. PMID:22740710

  18. Investigations on the metabolism of alkyl polyglucosides and their determination in waste water by means of liquid chromatography-electrospray mass spectrometry.

    PubMed

    Eichhorn, P; Knepper, T P

    1999-08-27

    Alkyl polyglucosides (APGs) were analyzed by reversed-phase liquid chromatography coupled to mass spectrometry with electrospray ionization. Analytes were separated according to the chain length of the alkyl homologues, whereas the separation of isomeric forms of the glucose moiety was achieved partially. Depending on the structure of the glucose ring the alkyl monoglucosides show a distinct affinity in terms of the formation of sodium and ammonium adduct ions. Metabolism of isomer pure alkyl monoglucosides was studied on a testfilter device to gather information about the degradation behavior and to obtain eventually poorly degradable metabolites. In spite of unsuccessful detection of any metabolites such as "polyglucoside alcanoic acids", a degradation pathway was proposed including the cleavage of the glucosidic bond as initial step. In addition, a method for the determination of APGs in municipal waste water effluent was developed using solid-phase extraction on reversed-phase material. Recovery rates were in the range of 66 to 98% for three spiked alkyl monoglucosides and a quantitation limit of 0.2 microg l(-1) was achieved.

  19. Liquid chromatography-mass spectrometry analysis of macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B in rat plasma for the pharmacokinetic investigation.

    PubMed

    Chen, Chun-Yun; Qi, Lian-Wen; Yi, Ling; Li, Ping; Wen, Xiao-Dong

    2009-01-15

    A liquid chromatography-electrospray ionization-mass spectrometry method has been developed and validated for identification and quantification of four major bioactive saponins in rat plasma after oral administration of extraction of saponins from Flos Lonicerae, i.e., macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B. Plasma samples were extracted with solid-phase extraction, separated on a Shim-pack CLC-ODS column and detected by MS in negative selective ion monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r(2)>0.999. The method showed the low limit quantification of 7.72, 6.06, 7.16, and 1.43 ng/mL for macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B, respectively. The inter- and intra-CV precision (R.S.D.) were all within 10% and accuracy (% bias) ranged from -10 to 10%. The overall recovery was more than 70%. This developed method was subsequently successfully applied to pharmacokinetic profiles of the four saponins in rats. After oral administration of extraction of saponins in rats, the concentration-time course was found to be the double peaks of curve.

  20. Theoretical Investigation of Small Polyatomic Ions Observed in Inductively Coupled Plasma Mass Spectrometry: HxCO+ and HxN2+ (x = 1, 2, 3)

    SciTech Connect

    Sears, K.; Ferguson, J.; Dudley, T.; Houk, R.; Gordon, M.

    2008-03-01

    Two series of small polyatomic ions, H{sub x}CO{sup +} and H{sub x}N{sub 2}{sup +} (x = 1, 2, 3), were systematically characterized using three correlated theoretical techniques: density functional theory using the B3LYP functional, spin-restricted second-order perturbation theory, and singles + doubles coupled cluster theory with perturbative triples. On the basis of thermodynamic data, the existence of these ions in inductively coupled plasma mass spectrometry (ICP-MS) experiments is not surprising since the ions are predicted to be considerably more stable than their corresponding dissociation products (by 30-170 kcal/mol). While each pair of isoelectronic ions exhibit very similar thermodynamic and kinetic characteristics, there are significant differences within each series. While the mechanism for dissociation of the larger ions occurs through hydrogen abstraction, the triatomic ions (HCO{sup +} and HN{sub 2}{sup +}) appear to dissociate by proton abstraction. These differing mechanisms help to explain large differences in the abundances of HN{sub 2}{sup +} and HCO{sup +} observed in ICP-MS experiments.

  1. Theoretical investigation of small polyatomic ions observed in inductively coupled plasma mass spectrometry: H(x)CO+ and H(x)N2(+) (x = 1, 2, 3).

    PubMed

    Sears, Kyle C; Ferguson, Jill W; Dudley, Timothy J; Houk, R S; Gordon, Mark S

    2008-03-27

    Two series of small polyatomic ions, HxCO+ and HxN2(+) (x = 1, 2, 3), were systematically characterized using three correlated theoretical techniques: density functional theory using the B3LYP functional, spin-restricted second-order perturbation theory, and singles + doubles coupled cluster theory with perturbative triples. On the basis of thermodynamic data, the existence of these ions in inductively coupled plasma mass spectrometry (ICP-MS) experiments is not surprising since the ions are predicted to be considerably more stable than their corresponding dissociation products (by 30-170 kcal/mol). While each pair of isoelectronic ions exhibit very similar thermodynamic and kinetic characteristics, there are significant differences within each series. While the mechanism for dissociation of the larger ions occurs through hydrogen abstraction, the triatomic ions (HCO+ and HN2(+)) appear to dissociate by proton abstraction. These differing mechanisms help to explain large differences in the abundances of HN2(+) and HCO+ observed in ICP-MS experiments.

  2. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    PubMed Central

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-01-01

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics. PMID:21728281

  3. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    SciTech Connect

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-06-16

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

  4. Investigations on the emission of fragrance allergens from scented toys by means of headspace solid-phase microextraction gas chromatography-mass spectrometry.

    PubMed

    Masuck, Ines; Hutzler, Christoph; Luch, Andreas

    2010-04-30

    In the revised European toy safety directive 2009/48/EC the application of fragrance allergens in children's toys is restricted. The focus of the present work lies on the instrumental analytics of 13 banned fragrance allergens, as well as on 11 fragrance allergens that require declaration when concentrations surpass 100 microg per gram material. Applying a mixture of ethyl acetate and toluene solid/liquid extraction was performed prior to quantitative analysis of mass contents of fragrances in scented toys. In addition, an easy-to-perform method for the determination of emitted fragrances at 23 degrees C (handling conditions) or at 40 degrees C (worst case scenario) has been worked out to allow for the evaluation of potential risks originating from inhalation of these compounds during handling of or playing with toys. For this purpose a headspace solid-phase microextraction (HS-SPME) technique was developed and coupled to subsequent gas chromatography-mass spectrometry (GC-MS) analysis. Fragrance allergens were adsorbed (extracted) from the gas phase onto an 85 microm polyacrylate fiber while incubating pieces of the scented toys in sealed headspace vials at 23 degrees C and 40 degrees C. Quantification of compounds was performed via external calibration. The newly developed headspace method was subsequently applied to five perfumed toys. As expected, the emission of fragrance allergens from scented toys depends on the temperature and on the content of fragrance allergens present in those samples. In particular at conditions mimicking worst case (40 degrees C), fragrance allergens in toys may pose a risk to children since considerable amounts of compound might be absorbed by lung tissue via breathing of contaminated air. 2010 Elsevier B.V. All rights reserved.

  5. Mass Spectrometry for Large Undergraduate Laboratory Sections

    NASA Astrophysics Data System (ADS)

    Illies, A.; Shevlin, P. B.; Childers, G.; Peschke, M.; Tsai, J.

    1995-08-01

    Mass spectrometry is routinely covered in undergraduate organic chemistry courses and a number of valuable laboratory experiments featuring its use have been discussed (1-7). Although such experiments work well at institutions with limited laboratory enrollments, we typically teach laboratories with enrollments of 160 or more in which it is difficult to allow each student to carry out a meaningful "hands on" mass spectrometry experiment. Since we feel that some practical experience with this technique is important, we have designed a simple gas chromatography-mass spectrometry (gc/ms) exercise that allows each student to analyze the products of a simple synthesis that they have performed. The exercise starts with the microscale SN2 synthesis of 1-bromobutane from 1-butanol as described by Williamson (8). The students complete the synthesis and place one drop of the distilled product in a screw capped vial. The vials are then sealed, labeled with the students name and taken to the mass spectrometry laboratory by a teaching assistant. Students are instructed to sign up for a 20-min block of time over the next few days in order to analyze their sample. When the student arrives at the laboratory, he or she adds 1 ml CH2Cl2 to the sample and injects 0.3 microliters of the solution into the gas chromatograph. The samples typically contain the 1-butanol starting material and the 1-bromobutane product along with traces of dibutyl ether. The figure shows a mass chromatogram along with the mass spectra of the starting material and product from an actual student run. For this analysis to be applicable to large numbers of students, the gc separation must be as rapid as possible. We have been able to analyze each sample in 6 minutes on a 30 m DB-5 capillary column with the following temperature program: 70 oC for 1 min, 70-80 oC at 10 oC/min, 86-140 oC at 67.5 oC/min, 140-210 oC at 70 oC/min, and 210 oC for 1 min. A mass range of 20-200 amu is scanned with a solvent delay of 2

  6. Cortisol production rates measured by liquid chromatography/mass spectrometry

    SciTech Connect

    Esteban, N.V.; Yergey, A.L. )

    1990-04-01

    Cortisol production rates (FPRs) in physiologic and pathologic states in humans have been investigated over the past 30 years. However, there has been conflicting evidence concerning the validity of the currently accepted value of FPRs in humans (12 to 15 mg/m2/d) as determined by radiotracer methodology. The present study reviews previous methods proposed for the measurement of FPRs in humans and discusses the applications of the first method for the direct determination of 24-hour plasma FPRs during continuous administration of a stable isotope, using a thermospray high-pressure liquid chromatography-mass spectrometry technique. The technique is fast, sensitive, and, unlike gas chromatography-mass spectrometry methods, does not require derivatization, allowing on-line detection and quantification of plasma cortisol after a simple extraction procedure. The results of determination of plasma FPRs by stable tracer/mass spectrometry are directly in units of mass/time and, unlike radiotracer methods, are independent of any determination of volume of distribution or cortisol concentration. Our methodology offers distinct advantages over radiotracer techniques in simplicity and reliability since only single measurements of isotope ratios are required. The technique was validated in adrenalectomized patients. Circadian variations in daily FRPs were observed in normal volunteers, and, to date, results suggest a lower FRP in normal children and adults than previously believed. 88 references.

  7. Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.

    ERIC Educational Resources Information Center

    Denoyer, Eric; And Others

    1982-01-01

    Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

  8. Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.

    ERIC Educational Resources Information Center

    Denoyer, Eric; And Others

    1982-01-01

    Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

  9. Challenges ahead for mass spectrometry and proteomics applications in epigenetics.

    PubMed

    Kessler, Benedikt M

    2010-02-01

    Inheritance of biological information to future generations depends on the replication of DNA and the Mendelian principle of distribution of genes. In addition, external and environmental factors can influence traits that can be propagated to offspring, but the molecular details of this are only beginning to be understood. The discoveries of DNA methylation and post-translational modifications on chromatin and histones provided entry points for regulating gene expression, an area now defined as epigenetics and epigenomics. Mass spectrometry turned out to be instrumental in uncovering molecular details involved in these processes. The central role of histone post-translational modifications in epigenetics related biological processes has revitalized mass spectrometry based investigations. In this special report, current approaches and future challenges that lay ahead due to the enormous complexity are discussed.

  10. Characterisation of DEFB107 by mass spectrometry

    NASA Astrophysics Data System (ADS)

    McCullough, Bryan J.; Eastwood, Hayden; Clark, Dave J.; Polfer, Nick C.; Campopiano, Dominic J.; Dorin, Julia A.; Maxwell, Alison; Langley, Ross J.; Govan, John R. W.; Bernstein, Summer L.; Bowers, Michael T.; Barran, Perdita E.

    2006-05-01

    Mammalian defensins are small endogenous cationic proteins which form a class of antimicrobial peptides that is part of the innate immune response of all mammalian species [R. Lehrer, Nat. Rev. Microbiol. 2 (9) (2004) 727; T. Ganz, R.I. Lehrer, Curr. Opin. Immunol. 6 (4) (1994) 584] [1] and [2]. We have developed mass spectrometry based strategies for characterising the structure-activity relationship of defensins [D.J. Campopiano, D.J. Clarke, N.C. Polfer, P.E. Barran, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, J. Biol. Chem. 279 (47) (2004) 48671; P.E. Barran, N.C. Polfer, D.J. Campopiano, D.J. Clarke, P.R.R. Langridge-Smith, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, R.P. Millar, M.T. Bowers, Int. J. Mass Spectrom. 240 (2005) 273] [3] and [4], and here we present data obtained from a five cysteine containing [beta]-defensin, DEFB107. The synthetic product of this human defensin exists with a glutathione capping group, its oxidation state and disulphide connectivity have been determined via accurate mass measurements and peptide mass mapping respectively, and despite possessing three disulphide bridges, it does not fit the [beta]-defensin canonical motif. With the use of molecular modelling, we have generated candidate geometries to discern the influence of disulphide bridging on the overall tertiary structure of DEFB107. These are compared with experimental results from ion mobility measurements. Defensins display activity against a wide variety of pathogens including both gram-negative and gram-positive bacteria. Their mechanism of mode of action is unknown, but is believed to involve defensin aggregation at cell surfaces, followed by cell permeabilisation and hence deathE To probe this mechanism, the localisation of DEFB107 in synthetic vesicles was studied using H/D exchange and mass spectrometry. The results obtained are used to analyse the antimicrobial activity of DEFB107.

  11. Interfacing membrane mimetics with mass spectrometry

    PubMed Central

    Marty, Michael T.; Hoi, Kin Kuan; Robinson, Carol V.

    2017-01-01

    Conspectus Membrane proteins play critical physiological roles and make up the majority of drug targets. Due to their generally low expression levels and amphipathic nature, membrane proteins represent challenging molecular entities for biophysical study. Mass spectrometry offers several sensitive approaches to study the biophysics of membrane proteins. By preserving noncovalent interactions in the gas phase and using collisional activation to remove solubilization agents inside the mass spectrometer, native mass spectrometry (MS) is capable of studying isolated assemblies that would be insoluble in aqueous solution, such as membrane protein oligomers and protein-lipid complexes. Conventional methods use detergent to solubilize the protein prior to electrospray ionization. Gas-phase activation inside the mass spectrometer removes the detergent to yield the isolated proteins with bound ligands. This approach has proven highly successful for ionizing membrane proteins. With the appropriate choice of detergents, membrane proteins with bound lipid species can be observed, which allows characterization of protein-lipid interactions. However, detergents have several limitations. They do not necessarily replicate the native lipid bilayer environment, and only a small number of protein-lipid interactions can be resolved. In this Account, we summarize the development of different membrane mimetics as cassettes for MS analysis of membrane proteins. Examples include amphipols, bicelles, and picodiscs with a special emphasis on lipoprotein Nanodiscs. Polydispersity and heterogeneity of the membrane mimetic cassette is a critical issue for study by MS. Ever more complex datasets consisting of overlapping protein charge states and multiple lipid-bound entities have required development of new computational, theoretical, and experimental approaches to interpret both mass and ion mobility spectra. We will present the rationale and limitations of these approaches. Starting with the

  12. [Application of mass spectrometry in mycology].

    PubMed

    Quiles Melero, Inmaculada; Peláez, Teresa; Rezusta López, Antonio; Garcia-Rodríguez, Julio

    2016-06-01

    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) is becoming an essential tool in most microbiology laboratories. At present, by using a characteristic fungal profile obtained from whole cells or through simple extraction protocols, MALDI-TOF MS allows the identification of pathogenic fungi with a high performance potential. This methodology decreases the laboratory turnaround time, optimizing the detection of mycoses. This article describes the state-of-the-art of the use of MALDI-TOF MS for the detection of human clinical fungal pathogens in the laboratory and discusses the future applications of this technology, which will further improve routine mycological diagnosis. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  13. Live single-cell mass spectrometry.

    PubMed

    Masujima, Tsutomu

    2009-08-01

    The history from bio-imaging to live single-cell mass spectrometry (MS) is herein reviewed. The limitation of the current bio-imaging method is probing only known molecules, and a method for finding new molecules is needed for cells which, however, show individual behaviors even in the same incubation dish. Single-cell MALDI-TOF/MS has been developed, but it can detect only molecules that can be easily ionized, and not be exhaustive. Recently, the contents of a single cell have been sucked out by a nano-electro spray tip, and directly introduced into MS by nano-spray ionization. Thousands of molecular peaks have been successfully and exhaustively detected, and an extraction method for key molecules was also developed. This new method is now being widely applied to explore site- or state-specific molecules in various aspects of cell dynamisms.

  14. Recent trends in inorganic mass spectrometry

    SciTech Connect

    Smith, D.H.; Barshick, C.M.; Duckworth, D.C.; Riciputi, L.R.

    1996-10-01

    The field of inorganic mass spectrometry has seen substantial change in the author`s professional lifetime (over 30 years). Techniques in their infancy 30 years ago have matured; some have almost disappeared. New and previously unthought of techniques have come into being; some of these, such as ICP-MS, are reasonably mature now, while others have some distance to go before they can be so considered. Most of these new areas provide fertile fields for researchers, both in the development of new analytical techniques and by allowing fundamental studies to be undertaken that were previously difficult, impossible, or completely unforeseen. As full coverage of the field is manifestly impossible within the framework of this paper, only those areas with which the author has personal contact will be discussed. Most of the work originated in his own laboratory, but that of other laboratories is covered where it seemed appropriate.

  15. Characterization of Microorganisms by MALDI Mass Spectrometry

    SciTech Connect

    Petersen, Catherine E.; Valentine, Nancy B.; Wahl, Karen L.

    2008-10-02

    Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for characterization and analysis of microorganisms, specifically bacteria, is described here as a rapid screening tool. The objective of this technique is not comprehensive protein analysis of a microorganism but rather a rapid screening of the organism and the accessible protein pattern for characterization and distinction. This method is based on the ionization of the readily accessible and easily ionizable portion of the protein profile of an organism that is often characteristic of different bacterial species. The utility of this screening approach is yet to reach its full potential but could be applied to food safety, disease outbreak monitoring in hospitals, culture stock integrity and verification, microbial forensics or homeland security applications.

  16. [Future applications of mass spectrometry in microbiology].

    PubMed

    Vila, Jordi; Zboromyrska, Yuliya; Burillo, Almudena; Bouza, Emilio

    2016-06-01

    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) has been vigorously introduced in many clinical microbiology laboratories for the rapid and accurate identification of bacteria and fungi. In fact, the implementation of this methodology can be considered a revolution in these laboratories. In addition to microbial identification, MALDI-TOF MS is being used for the detection of some mechanisms of antibiotic resistance and for the molecular typing of bacteria. A number of current and future applications that increase the versatility of this methodology may also be mentioned. Among these are its direct application on clinical samples, the detection of toxins or specific microbial antigens, and its application in the fields of virology and parasitology. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  17. Glass microfabricated nebulizer chip for mass spectrometry.

    PubMed

    Saarela, Ville; Haapala, Markus; Kostiainen, Risto; Kotiaho, Tapio; Franssila, Sami

    2007-05-01

    A microfluidic nebulizer chip for mass spectrometry is presented. It is an all-glass device which consists of fusion bonded Pyrex wafers with embedded flow channels and a nozzle at the chip edge. A platinum heater is located on the wafer backside. Fabrication of the chip is detailed, especially glass deep etching, wafer bonding, and metal patterning. Various process combinations of bonding and metallization have been considered (anodic bonding vs. fusion bonding; heater inside/outside channel; metallization before/after bonding; platinum lift-off vs. etching). The chip vaporizes the liquid sample (0.1-10 microL min(-1)) and mixes it with a nebulizer gas (ca. 100 sccm N2). Operating temperatures can go up to 500 degrees C ensuring efficient vaporization. Thermal insulation of the glass ensures low temperatures at the far end of the chip, enabling easy interconnections.

  18. Functional phosphoproteomic mass spectrometry-based approaches

    PubMed Central

    2012-01-01

    Mass Spectrometry (MS)-based phosphoproteomics tools are crucial for understanding the structure and dynamics of signaling networks. Approaches such as affinity purification followed by MS have also been used to elucidate relevant biological questions in health and disease. The study of proteomes and phosphoproteomes as linked systems, rather than research studies of individual proteins, are necessary to understand the functions of phosphorylated and un-phosphorylated proteins under spatial and temporal conditions. Phosphoproteome studies also facilitate drug target protein identification which may be clinically useful in the near future. Here, we provide an overview of general principles of signaling pathways versus phosphorylation. Likewise, we detail chemical phosphoproteomic tools, including pros and cons with examples where these methods have been applied. In addition, basic clues of electrospray ionization and collision induced dissociation fragmentation are detailed in a simple manner for successful phosphoproteomic clinical studies. PMID:23369623

  19. Accelerator mass spectrometry (AMS) in plutonium analysis.

    PubMed

    Strumińska-Parulska, Dagmara I

    The paper summarizes the results of the (240)Pu/(239)Pu atomic ratio studies in atmospheric fallout samples collected in 1986 over Gdynia (Poland) as well as three Baltic fish species collected in 1997 using the accelerator mass spectrometry. A new generation of AMS has been developed during last years and this method is an efficient and good technique to measure long-lived radioisotopes in the environment and provides the most accurate determination of the atomic ratios between (240)Pu and (239)Pu. The nuclide compositions of plutonium in filter samples correspond to their means of production. AMS measurements of atmospheric fallout collected in April showed sufficient increase of the (240)Pu/(239)Pu atomic ratio from 0.28 from March to 0.47. Also such high increase of (240)Pu/(239)Pu atomic ratio, close to reactor core (240)Pu/(239)Pu atomic ratio, was observed in September and equaled 0.47.

  20. Mass spectrometry and Web 2.0.

    PubMed

    Murray, Kermit K

    2007-10-01

    The term Web 2.0 is a convenient shorthand for a new era in the Internet in which users themselves are both generating and modifying existing web content. Several types of tools can be used. With social bookmarking, users assign a keyword to a web resource and the collection of the keyword 'tags' from multiple users form the classification of these resources. Blogs are a form of diary or news report published on the web in reverse chronological order and are a popular form of information sharing. A wiki is a website that can be edited using a web browser and can be used for collaborative creation of information on the site. This article is a tutorial that describes how these new ways of creating, modifying, and sharing information on the Web are being used for on-line mass spectrometry resources.

  1. In situ secondary ion mass spectrometry analysis

    SciTech Connect

    Groenewold, G.S.; Applehans, A.D.; Ingram, J.C.; Delmore, J.E.; Dahl, D.A.

    1993-01-01

    The direct detection of tributyl phosphate (TBP) on rocks using molecular beam surface analysis [MBSA or in situ secondary ion mass spectrometry (SIMS)] is demonstrated. Quantities as low as 250 ng were detected on basalt and sandstone with little or no sample preparation. Detection of TBP on soil has proven to be more problematic and requires further study. Ethylenediaminetetraacetic acid (EDTA) is more difficult to detect because it is very reactive with surfaces of interest. Nevertheless, it is possible to detect EDTA if the acidity of the surface is controlled. The detection of EDTA-metal complexes is currently an open question, but evidence is presented for the detection of ions arising from a EDTA-lead complex. Carboxylic acids (i.e., citric, ascorbic, malic, succinic, malonic, and oxalic) give characteristic SIM spectra, but their detection on sample surfaces awaits evaluation.

  2. Dating silk by capillary electrophoresis mass spectrometry.

    PubMed

    Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

    2011-10-01

    A new capillary electrophoresis mass spectrometry (CE-MS) technique is introduced for age estimation of silk textiles based on amino acid racemization rates. With an L to D conversion half-life of ~2500 years for silk (B. mori) aspartic acid, the technique is capable of dating silk textiles ranging in age from several decades to a few-thousand-years-old. Analysis required only ~100 μg or less of silk fiber. Except for a 2 h acid hydrolysis at 110 °C, no other sample preparation is required. The CE-MS analysis takes ~20 min, consumes only nanoliters of the amino acid mixture, and provides both amino acid composition profiles and D/L ratios for ~11 amino acids.

  3. Multiplex mass spectrometry imaging for latent fingerprints.

    PubMed

    Yagnik, Gargey B; Korte, Andrew R; Lee, Young Jin

    2013-01-01

    We have previously developed in-parallel data acquisition of orbitrap mass spectrometry (MS) and ion trap MS and/or MS/MS scans for matrix-assisted laser desorption/ionization MS imaging (MSI) to obtain rich chemical information in less data acquisition time. In the present study, we demonstrate a novel application of this multiplex MSI methodology for latent fingerprints. In a single imaging experiment, we could obtain chemical images of various endogenous and exogenous compounds, along with simultaneous MS/MS images of a few selected compounds. This work confirms the usefulness of multiplex MSI to explore chemical markers when the sample specimen is very limited. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Hutchinson, Robert W.; McLachlin, Katherine M.; Riquelme, Paloma; Haarer, Jan; Broichhausen, Christiane; Ritter, Uwe; Geissler, Edward K.; Hutchinson, James A.

    2015-01-01

    ABSTRACT New analytical techniques for multiparametric characterisation of individual cells are likely to reveal important information about the heterogeneity of immunological responses at the single-cell level. In this proof-of-principle study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to the problem of concurrently detecting 24 lineage and activation markers expressed by human leucocytes. This approach was sufficiently sensitive and specific to identify subpopulations of isolated T, B, and natural killer cells. Leucocyte subsets were also accurately detected within unfractionated peripheral blood mononuclear cells preparations. Accordingly, we judge LA-ICP-MS to be a suitable method for assessing expression of multiple tissue antigens in solid-phase biological specimens, such as tissue sections, cytospins, or cells grown on slides. These results augur well for future development of LA-ICP-MS–based bioimaging instruments for general users. PMID:27500232

  5. Deciphering the histone code using mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ueberheide, Beatrix M.; Mollah, Sahana

    2007-01-01

    During the past decade, studies surrounding chromatin research have grown exponentially. A major focus of chromatin biology is centered on understanding of how histone modifications alter chromatin structure at the molecular and mechanistic levels. Discoveries are being made at a rapid pace due to the advent of new and innovative techniques. Mass spectrometry has emerged as a powerful tool in the field of histone research due to its speed, sensitivity, and ease of use. This has resulted in the identification of a number of novel histone modification sites. In consequence, new roles in biological processes have been discovered and hypothetical models, such as the `histone code' have been reaffirmed or refined. One significant advantage to using mass spectrometric techniques is that the combinations of modifications on different sites can be determined which is crucial to deciphering the `histone code'. In this manuscript, the mass spectrometric approaches developed over the past decade for both qualitative and quantitative analysis of histone post-translational modifications (PTMs) are discussed.

  6. Atmospheric-pressure Penning ionization mass spectrometry.

    PubMed

    Hiraoka, Kenzo; Fujimaki, Susumu; Kambara, Shizuka; Furuya, Hiroko; Okazaki, Shigemitsu

    2004-01-01

    A preliminary study on the atmospheric-pressure Penning ionization (APP(e)I) of gaseous organic compounds with Ar* has been made. The metastable argon atoms (Ar*: 11.55 eV for (3)P(2) and 11.72 eV for (3)P(0)) were generated by the negative-mode corona discharge of atmospheric-pressure argon gas. By applying a high positive voltage (+500 to +1000 V) to the stainless steel capillary for the sample introduction (0.1 mm i.d., 0.3 mm o.d.), strong ion signals could be obtained. The ions formed were sampled through an orifice into the vacuum and mass-analyzed by an orthogonal time-of-flight mass spectrometer. The major ions formed by APP(e)I are found to be molecular-related ions for alkanes, aromatics, and oxygen-containing compounds. Because only the molecules with ionization energies less than the internal energy of Ar* are ionized, the present method will be a selective and highly sensitive interface for gas chromatography/mass spectrometry.

  7. Mass spectrometry-based quantitative proteomic profiling.

    PubMed

    Yan, Wei; Chen, Sharon S

    2005-05-01

    Quantitative proteomics involves the identification and quantitation of protein components in various biological systems. Stable isotope labelling technology, by both metabolic and chemical methods, has been the most commonly used approach for global proteome-wide profiling. Recently, its capability has been extended from labelled pairs to multiple labels, allowing for the simultaneous quantification of multiplex samples. The ion intensity-based quantitative approach has progressively gained more popularity as mass spectrometry performance has improved significantly. Although some success has been reported, it remains difficult comprehensively to characterise the global proteome, due to its enormous complexity and dynamic range. The use of sub-proteome fractionation techniques permits a simplification of the proteome and provides a practical step towards the ultimate dissection of the entire proteome. Further development of the technology for targeting sub-proteomes on a functional basis - such as selecting proteins with differential expression profiles from mass spectrometric analyses, for further mass spectrometric sequencing in an intelligent manner--is expected in the near future.

  8. Forensic applications of ambient ionization mass spectrometry.

    PubMed

    Ifa, Demian R; Jackson, Ayanna U; Paglia, Giuseppe; Cooks, R Graham

    2009-08-01

    This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques--to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin--are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents.

  9. Enantioselectivity of mass spectrometry: challenges and promises.

    PubMed

    Awad, Hanan; El-Aneed, Anas

    2013-01-01

    With the fast growing market of pure enantiomer drugs and bioactive molecules, new chiral-selective analytical tools have been instigated including the use of mass spectrometry (MS). Even though MS is one of the best analytical tools that has efficiently been used in several pharmaceutical and biological applications, traditionally MS is considered as a "chiral-blind" technique. This limitation is due to the MS inability to differentiate between two enantiomers of a chiral molecule based merely on their masses. Several approaches have been explored to assess the potential role of MS in chiral analysis. The first approach depends on the use of MS-hyphenated techniques utilizing fast and sensitive chiral separation tools such as liquid chromatography (LC), gas chromatography (GC), and capillary electrophoresis (CE) coupled to MS detector. More recently, several alternative separation techniques have been evaluated such as supercritical fluid chromatography (SFC) and capillary electrochromatography (CEC); the latter being a hybrid technique that combines the efficiency of CE with the selectivity of LC. The second approach is based on using the MS instrument solely for the chiral recognition. This method depends on the behavioral differences between enantiomers towards a foreign molecule and the ability of MS to monitor such differences. These behavioral differences can be divided into three types: (i) differences in the enantiomeric affinity for association with the chiral selector, (ii) differences of the enantiomeric exchange rate with a foreign reagent, and (iii) differences in the complex MS dissociation behaviors of the enantiomers. Most recently, ion mobility spectrometry was introduced to qualitatively and quantitatively evaluate chiral compounds. This article provides an overview of MS role in chiral analysis by discussing MS based methodologies and presenting the challenges and promises associated with each approach.

  10. Investigations of Acetate Chemical Ionization Mass Spectrometry (NIPT-CIMS): Underlying Chemistry, Calibrations, and Operational Considerations for the Detection of Carboxylic Acids and Other Species

    NASA Astrophysics Data System (ADS)

    Brophy, P.; Farmer, D.

    2015-12-01

    The growing use of high resolution time-of-flight chemical ionization mass spectrometers (HR-TOF-CIMS) as applied to gas and particle measurements requires a thorough understanding of the underlying chemistry to ensure accurate molecular identification. These systems are deployed using a number of reagent ion chemistries in both the positive and negative mode. Moreover, high resolution time-of-flight mass spectrometers make it possible to detect and (potentially) quantify species without the use of authentic standards. Acetate CIMS (or negative-ion proton-transfer CIMS) detects species by abstracting a proton from carboxylic acids, nitrated phenols, and other species with acidic protons. Clustering reactions are also known to occur, complicating analysis. proper interpretation of the mass spectra requires understanding these mechanisms and controlling for unwanted ionization processes. We investigate the ability to control for clustering reactions using authentic standards under various clustering regimes while maintaining ion transmission efficiency in simple and complex matrices. The feasibility of using isotopically labeled acetate to unambiguously identify clusters is also investigated. Bulk metrics for describing the spectra (oxygen:carbon, oxidation state, average carbon number, etc) are also investigated to understand their susceptibility to experimental configuration.

  11. Quantitative monitoring of tamoxifen in human plasma extended to 40 metabolites using liquid-chromatography high-resolution mass spectrometry: new investigation capabilities for clinical pharmacology.

    PubMed

    Dahmane, Elyes; Boccard, Julien; Csajka, Chantal; Rudaz, Serge; Décosterd, Laurent; Genin, Eric; Duretz, Bénédicte; Bromirski, Maciej; Zaman, Khalil; Testa, Bernard; Rochat, Bertrand

    2014-04-01

    Liquid-chromatography (LC) high-resolution (HR) mass spectrometry (MS) analysis can record HR full scans, a technique of detection that shows comparable selectivity and sensitivity to ion transitions (SRM) performed with triple-quadrupole (TQ)-MS but that allows de facto determination of "all" ions including drug metabolites. This could be of potential utility in in vivo drug metabolism and pharmacovigilance studies in order to have a more comprehensive insight in drug biotransformation profile differences in patients. This simultaneous quantitative and qualitative (Quan/Qual) approach has been tested with 20 patients chronically treated with tamoxifen (TAM). The absolute quantification of TAM and three metabolites in plasma was realized using HR- and TQ-MS and compared. The same LC-HR-MS analysis allowed the identification and relative quantification of 37 additional TAM metabolites. A number of new metabolites were detected in patients' plasma including metabolites identified as didemethyl-trihydroxy-TAM-glucoside and didemethyl-tetrahydroxy-TAM-glucoside conjugates corresponding to TAM with six and seven biotransformation steps, respectively. Multivariate analysis allowed relevant patterns of metabolites and ratios to be associated with TAM administration and CYP2D6 genotype. Two hydroxylated metabolites, α-OH-TAM and 4'-OH-TAM, were newly identified as putative CYP2D6 substrates. The relative quantification was precise (<20 %), and the semiquantitative estimation suggests that metabolite levels are non-negligible. Metabolites could play an important role in drug toxicity, but their impact on drug-related side effects has been partially neglected due to the tremendous effort needed with previous MS technologies. Using present HR-MS, this situation should evolve with the straightforward determination of drug metabolites, enlarging the possibilities in studying inter- and intra-patients drug metabolism variability and related effects.

  12. Alkylation of DNA by melphalan: investigation of capillary liquid chromatography-electrospray ionization tandem mass spectrometry in the study of the adducts at the nucleoside level.

    PubMed

    Van den Driessche, Bart; Lemière, Filip; Van Dongen, Walter; Esmans, Eddy L

    2003-02-25

    Nitrogen mustards are among the oldest cancer chemotherapeutic agents and remain the drugs of choice for treatment of many human cancers. A serious complication of treatment with nitrogen mustards is the increased risk of a secondary leukaemia in long-term survivors because not all alkylating agent interactions with DNA result in cell death. In an earlier study 2'-deoxy-5'-mononucleotide/melphalan adducts have been analysed by us by LC-ES MSMS. In this work we want to present the first results of the analysis of the corresponding 2'-deoxynucleoside/melphalan adducts from DNA hydrolysates by column switching/capillary LC-ES tandem mass spectrometry. Nucleosides, compared to nucleotides, give better chromatographic results and show a good sensitivity under electrospray (+) [ES(+)] ionisation. Several adducts were identified under ES(+) conditions. Mono-alkylated nucleoside adducts alkylated at the base moiety were identified for dGuo, dCyd and dAdo. Structures were identified by recording the low-energy CAD product ion scans. Also a mono-alkylated nucleotide pdA with alkylation position at the phosphate moiety could be detected. This proves that in the case of phosphate alkylation the enzymatic dephosphorylation reaction was inhibited. A Jurkat cell suspension was treated with melphalan (1 mM) and incubated at 37 degrees C (5% CO(2)). After 6 and 48 h, the DNA was isolated and enzymatically hydrolysed. The corresponding nucleoside pool was evaluated with the developed LC-MS method. In the 48-h experiment, one adduct could be identified as a N-7 alkylated dGuo. In the 6-h experiment, no adducts could be found. Additional experiments were done wherein Jurkat-DNA, isolated from a non-treated cell culture, was treated with melphalan. These results were analogous with the data found in melphalan-treated calf thymus DNA. Additionally, we tried to determine the exact alkylation position by interpreting high-resolution fragmentation spectra.

  13. Investigation of Exhaled Breath Samples from Patients with Alzheimer's Disease Using Gas Chromatography-Mass Spectrometry and an Exhaled Breath Sensor System.

    PubMed

    Lau, Hui-Chong; Yu, Joon-Boo; Lee, Ho-Won; Huh, Jeung-Soo; Lim, Jeong-Ok

    2017-08-03

    Exhaled breath is a body secretion, and the sampling process of this is simple and cost effective. It can be non-invasively collected for diagnostic procedures. Variations in the chemical composition of exhaled breath resulting from gaseous exchange in the extensive capillary network of the body are proposed to be associated with pathophysiological changes. In light of the foreseeable potential of exhaled breath as a diagnostic specimen, we used gas chromatography and mass spectrometry (GC-MS) to study the chemical compounds present in exhaled breath samples from patients with Alzheimer's disease (AD), Parkinson's disease (PD), and from healthy individuals as a control group. In addition, we also designed and developed a chemical-based exhaled breath sensor system to examine the distribution pattern in the patient and control groups. The results of our study showed that several chemical compounds, such as 1-phenantherol and ethyl 3-cyano-2,3-bis (2,5,-dimethyl-3-thienyl)-acrylate, had a higher percentage area in the AD group than in the PD and control groups. These results may indicate an association of these chemical components in exhaled breath with the progression of disease. In addition, in-house fabricated exhaled breath sensor systems, containing several types of gas sensors, showed significant differences in terms of the normalized response of the sensitivity characteristics between the patient and control groups. A subsequent clustering analysis was able to distinguish between the AD patients, PD patients, and healthy individuals using principal component analysis, Sammon's mapping, and a combination of both methods, in particular when using the exhaled breath sensor array system A consisting of eight sensors. With this in mind, the exhaled breath sensor system could provide alternative option for diagnosis and be applied as a useful, effective tool for the screening and diagnosis of AD in the near future.

  14. Investigation of Exhaled Breath Samples from Patients with Alzheimer’s Disease Using Gas Chromatography-Mass Spectrometry and an Exhaled Breath Sensor System

    PubMed Central

    Lau, Hui-Chong; Yu, Joon-Boo; Lee, Ho-Won; Huh, Jeung-Soo; Lim, Jeong-Ok

    2017-01-01

    Exhaled breath is a body secretion, and the sampling process of this is simple and cost effective. It can be non-invasively collected for diagnostic procedures. Variations in the chemical composition of exhaled breath resulting from gaseous exchange in the extensive capillary network of the body are proposed to be associated with pathophysiological changes. In light of the foreseeable potential of exhaled breath as a diagnostic specimen, we used gas chromatography and mass spectrometry (GC-MS) to study the chemical compounds present in exhaled breath samples from patients with Alzheimer’s disease (AD), Parkinson’s disease (PD), and from healthy individuals as a control group. In addition, we also designed and developed a chemical-based exhaled breath sensor system to examine the distribution pattern in the patient and control groups. The results of our study showed that several chemical compounds, such as 1-phenantherol and ethyl 3-cyano-2,3-bis (2,5,-dimethyl-3-thienyl)-acrylate, had a higher percentage area in the AD group than in the PD and control groups. These results may indicate an association of these chemical components in exhaled breath with the progression of disease. In addition, in-house fabricated exhaled breath sensor systems, containing several types of gas sensors, showed significant differences in terms of the normalized response of the sensitivity characteristics between the patient and control groups. A subsequent clustering analysis was able to distinguish between the AD patients, PD patients, and healthy individuals using principal component analysis, Sammon’s mapping, and a combination of both methods, in particular when using the exhaled breath sensor array system A consisting of eight sensors. With this in mind, the exhaled breath sensor system could provide alternative option for diagnosis and be applied as a useful, effective tool for the screening and diagnosis of AD in the near future. PMID:28771180

  15. Plasticity of Cytochrome P450 2B4 as Investigated by Hydrogen-Deuterium Exchange Mass Spectrometry and X-ray Crystallography*

    PubMed Central

    Wilderman, P. Ross; Shah, Manish B.; Liu, Tong; Li, Sheng; Hsu, Simon; Roberts, Arthur G.; Goodlett, David R.; Zhang, Qinghai; Woods, Virgil L.; Stout, C. David; Halpert, James R.

    2010-01-01

    Crystal structures of the xenobiotic metabolizing cytochrome P450 2B4 have demonstrated markedly different conformations in the presence of imidazole inhibitors or in the absence of ligand. However, knowledge of the plasticity of the enzyme in solution has remained scant. Thus, hydrogen-deuterium exchange mass spectrometry (DXMS) was utilized to probe the conformations of ligand-free P450 2B4 and the complex with 4-(4-chlorophenyl)imidazole (4-CPI) or 1-biphenyl-4-methyl-1H-imidazole (1-PBI). The results of DXMS indicate that the binding of 4-CPI slowed the hydrogen-deuterium exchange rate over the B′- and C-helices and portions of the F-G-helix cassette compared with P450 2B4 in the absence of ligands. In contrast, there was little difference between the ligand-free and 1-PBI-bound exchange sets. In addition, DXMS suggests that the ligand-free P450 2B4 is predominantly open in solution. Interestingly, a new high resolution structure of ligand-free P450 2B4 was obtained in a closed conformation very similar to the 4-CPI complex. Molecular dynamics simulations performed with the closed ligand-free structure as the starting point were used to probe the energetically accessible conformations of P450 2B4. The simulations were found to equilibrate to a conformation resembling the 1-PBI-bound P450 2B4 crystal structure. The results indicate that conformational changes observed in available crystal structures of the promiscuous xenobiotic metabolizing cytochrome P450 2B4 are consistent with its solution structural behavior. PMID:20880847

  16. Investigation on pharmacokinetics, tissue distribution and excretion of a novel platinum anticancer agent in rats by inductively coupled plasma mass spectrometry (ICP-MS).

    PubMed

    Zhao, Jie; Wen, Yanli; Zhang, Wei; Zhao, Di; Fan, Ali; Zhang, Yongjie; Deng, Shuhua; Wang, Xin; Liu, Qingwang; Lu, Yang; Wang, Zhimei; Gou, Shaohua; Chen, Xijing

    2014-08-01

    1. DN604 is a new platinum agent with encouraging anticancer activity. The present study was to explore the pharmacokinetic profiles, distribution and excretion of platinum in Sprague-Dawley rats after intravenous administration of DN604. A sensitive and selective inductively coupled plasma mass spectrometry (ICP-MS) method was established for determination of platinum in biological specimens. The pharmacokinetic parameters were calculated by a non-compartmental method. 2. The area under concentration-time curve AUC0-t and AUC0-∞ for platinum originating from DN604 at 10 mg/kg were 25.15 ± 1.29 and 28.72 ± 1.04 μg/hml, respectively. The mean residence time MRT was 36.59 ± 6.65 h. The volume of distribution Vz was 11.42 ± 2.49 l/kg and clearance CL was 0.18 ± 0.01 l/h/kg. In addition, the elimination half-life T1/2z was 44.83 ± 9.75 h. After intravenous administration of DN604, platinum was extensively distributed in most of tested tissues except brain. The majority of platinum excreted via urine, and its accumulative excretion ratio during the period of 120 h was 63.5% ± 7.7% for urine, but only 6.94% ± 0.11% for feces. 3. The satisfactory half-life, wide distribution and high excretion made this novel platinum agent worthy of further research and development.

  17. The role of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to test blood and urine samples for the toxicological investigation of drug-facilitated crimes.

    PubMed

    Deveaux, Marc; Chèze, Marjorie; Pépin, Gilbert

    2008-04-01

    The authors present an overview of the drug-facilitated crime (DFC) phenomenon, especially in France. Recently, there has been an increase in reports of incidents (mainly sexual assaults and robbery) as well as in scientific publications and congress presentations on the topic. From enquiries conducted nationally, a list of drugs reportedly associated with DFC was established and includes benzodiazepines and benzodiazepine-like drugs (zolpidem, zopiclone), minor tranquilizers and neuroleptics, barbiturates, narcotics, hallucinogens, and anaesthetics. Some of these molecules are specific to France in DFC cases. A study using healthy volunteers who had taken benzodiazepines (lorazepam, bromazepam, flunitrazepam, clonazepam), zolpidem and zopiclone, showed that the only way to increase the duration of detection of these drugs is to use liquid chromatography-tandem mass spectrometry (LC-MS/MS) to test blood and urine samples. The very high sensitivity of this method appears to be an essential condition to document the cases, because the drugs tested were still detectable in urine at least 6 days after the ingestion of one therapeutic dose. Limits of detection were always lower than 0.5 ng/mL in urine. The actual list of molecules and metabolites the authors screened for in urine and blood by LC-MS/MS, in every DFC, is given in detail: 25 benzodiazepines and benzodiazepine-like drugs, 11 minor tranquilizers and neuroleptics, 2 barbiturates, 12 narcotics, 4 hallucinogens, and 1 anaesthetic. However, the distinction between continual therapeutic use of a psychotropic drug or illegal narcotic and a single ingestion has to be documented by sequential analysis of hair, again with LC-MS/MS.

  18. Investigation of pyrrolizidine alkaloids including their respective N-oxides in selected food products available in Hong Kong by liquid chromatography electrospray ionisation mass spectrometry.

    PubMed

    Chung, Stephen W C; Lam, Aaron C H

    2017-07-01

    This study determined the levels of pyrrolizidine alkaloids (PAs), including their respective N-oxides, in foodstuffs available in Hong Kong by liquid chromatography-electrospray ionisation tandem mass spectrometry. A total of 234 samples (48 food items) were collected randomly from a local market and analysed. About 50% of samples were found to contain detectable amount of PAs. Amongst the 48 food items, PAs were not detected in 11 food items, including barley flour, beef, cattle liver, pork, pig liver, chicken meat, chicken liver, milk, non-fermented tea, Melissa tea and linden tea. For those found to contain detectable PAs, the summed PA content ranged up to 11,000 µg kg(-1). The highest sum of PA content among the 37 food items calculated with lower bound was cumin seed, then followed by oregano, tarragon and herbs de Provence with ranges of 2.5-11,000, 1.5-5100, 8.0-3300 and 18-1300 µg kg(-1) respectively. Among the samples, the highest sum of PA content was detected in a cumin seed sample (11,000 µg kg(-1)), followed by an oregano (5100 µg kg(-1)), a tarragon (3300 µg kg(-1)) and a herbs de Provence (1300 µg kg(-1)). In general, the results of this study agreed well with other published results in peer-reviewed journals, except that the total PAs in honey and specific tea infusion in this study were comparatively lower.

  19. Nanospray ion mobility mass spectrometry of selected high mass species.

    PubMed

    Campuzano, Iain; Giles, Kevin

    2011-01-01

    The introduction of electrospray ionization (ESI) and in particular nano-electrospray (nESI) has enabled the routine mass spectrometric (MS) analysis of large protein complexes in native aqueous buffers. Time-of-flight (ToF) mass spectrometers, in particular the hybrid quadrupole time-of-flight (Q-ToF) instruments, are well suited to the analysis of large protein complexes. When ionized under native-MS conditions, protein complexes routinely exhibit multiple charge states in excess of m/z 6,000, well above the standard mass range of many quadrupole or ion cyclotron-based instruments. The research area of native MS has expanded considerably in the last decade and has shown particular relevance in the area of protein structure determination. Researchers are now able to routinely measure intact MS spectra of protein complexes above 1 MDa in mass. The advent of ion mobility mass spectrometry (IM-MS), in combination with molecular dynamics (MD) studies, is now allowing researchers to infer the shape of the protein complex being analyzed. Herein, we describe how to acquire IM-MS data that ranges from inorganic salt clusters of caesium iodide (CsI) to large biomolecular complexes such as the chaperone protein GroEL.

  20. Advances in imaging secondary ion mass spectrometry for biological samples

    SciTech Connect

    Boxer, Steven G.; Kraft, Mary L.; Weber, Peter K.

    2008-12-16

    Imaging mass spectrometry combines the power of mass spectrometry to identify complex molecules based on mass with sample imaging. Recent advances in secondary ion mass spectrometry have improved sensitivity and spatial resolution, so that these methods have the potential to bridge between high-resolution structures obtained by X-ray crystallography and cyro-electron microscopy and ultrastructure visualized by conventional light microscopy. Following background information on the method and instrumentation, we address the key issue of sample preparation. Because mass spectrometry is performed in high vacuum, it is essential to preserve the lateral organization of the sample while removing bulk water, and this has been a major barrier for applications to biological systems. Furthermore, recent applications of imaging mass spectrometry to cell biology, microbial communities, and biosynthetic pathways are summarized briefly, and studies of biological membrane organization are described in greater depth.

  1. Advantageous Uses of Mass Spectrometry for the Quantification of Proteins

    PubMed Central

    Hale, John E.

    2013-01-01

    Quantitative protein measurements by mass spectrometry have gained wide acceptance in research settings. However, clinical uptake of mass spectrometric protein assays has not followed suit. In part, this is due to the long-standing acceptance by regulatory agencies of immunological assays such as ELISA assays. In most cases, ELISAs provide highly accurate, sensitive, relatively inexpensive, and simple assays for many analytes. The barrier to acceptance of mass spectrometry in these situations will remain high. However, mass spectrometry provides solutions to certain protein measurements that are difficult, if not impossible, to accomplish by immunological methods. Cases where mass spectrometry can provide solutions to difficult assay development include distinguishing between very closely related protein species and monitoring biological and analytical variability due to sample handling and very high multiplexing capacity. This paper will highlight several examples where mass spectrometry has made certain protein measurements possible where immunological techniques have had a great difficulty. PMID:23365751

  2. Advances in imaging secondary ion mass spectrometry for biological samples

    DOE PAGES

    Boxer, Steven G.; Kraft, Mary L.; Weber, Peter K.

    2008-12-16

    Imaging mass spectrometry combines the power of mass spectrometry to identify complex molecules based on mass with sample imaging. Recent advances in secondary ion mass spectrometry have improved sensitivity and spatial resolution, so that these methods have the potential to bridge between high-resolution structures obtained by X-ray crystallography and cyro-electron microscopy and ultrastructure visualized by conventional light microscopy. Following background information on the method and instrumentation, we address the key issue of sample preparation. Because mass spectrometry is performed in high vacuum, it is essential to preserve the lateral organization of the sample while removing bulk water, and this hasmore » been a major barrier for applications to biological systems. Furthermore, recent applications of imaging mass spectrometry to cell biology, microbial communities, and biosynthetic pathways are summarized briefly, and studies of biological membrane organization are described in greater depth.« less

  3. Advancements in mass spectrometry for biological samples: Protein chemical cross-linking and metabolite analysis of plant tissues

    SciTech Connect

    Klein, Adam

    2015-01-01

    This thesis presents work on advancements and applications of methodology for the analysis of biological samples using mass spectrometry. Included in this work are improvements to chemical cross-linking mass spectrometry (CXMS) for the study of protein structures and mass spectrometry imaging and quantitative analysis to study plant metabolites. Applications include using matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to further explore metabolic heterogeneity in plant tissues and chemical interactions at the interface between plants and pests. Additional work was focused on developing liquid chromatography-mass spectrometry (LC-MS) methods to investigate metabolites associated with plant-pest interactions.

  4. Mass Spectrometry of Acoustically Levitated Droplets

    PubMed Central

    Westphall, Michael S.; Jorabchi, Kaveh; Smith, Lloyd M.

    2008-01-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air–droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-μL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing chargere combination after ion desorption. PMID:18582090

  5. Mass spectrometry of acoustically levitated droplets.

    PubMed

    Westphall, Michael S; Jorabchi, Kaveh; Smith, Lloyd M

    2008-08-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air-droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-microL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing charge recombination after ion desorption.

  6. Single-protein nanomechanical mass spectrometry in real time

    PubMed Central

    Hanay, M.S.; Kelber, S.; Naik, A.K.; Chi, D.; Hentz, S.; Bullard, E.C.; Colinet, E.; Duraffourg, L.; Roukes, M.L.

    2012-01-01

    Nanoelectromechanical systems (NEMS) resonators can detect mass with exceptional sensitivity. Previously, mass spectra from several hundred adsorption events were assembled in NEMS-based mass spectrometry using statistical analysis. Here, we report the first realization of single-molecule NEMS-based mass spectrometry in real time. As each molecule in the sample adsorbs upon the NEMS resonator, its mass and the position-of-adsorption are determined by continuously tracking two driven vibrational modes of the device. We demonstrate the potential of multimode NEMS-based mass spectrometry by analyzing IgM antibody complexes in real-time. NEMS-MS is a unique and promising new form of mass spectrometry: it can resolve neutral species, provides resolving power that increases markedly for very large masses, and allows acquisition of spectra, molecule-by-molecule, in real-time. PMID:22922541

  7. Laser ablation/Fourier transform mass spectrometry of polymers

    NASA Astrophysics Data System (ADS)

    Creasy, William R.; Brenna, J. T.

    1989-10-01

    Laser ablation/ionization followed by Fourier transform mass spectrometry is used to identify and characterize polymers. The mass spectra of several polymers are discussed, including polyimide, polyamic acid, Dupont Tefzel, and polyphenylene sulfide.

  8. Reliability of veterinary drug residue confirmation: high resolution mass spectrometry versus tandem mass spectrometry.

    PubMed

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2015-01-26

    Confirmation of suspected residues has been a long time domain of tandem triple quadrupole mass spectrometry (QqQ). The currently most widely used confirmation strategy relies on the use of two selected reaction monitoring signals (SRM). The details of this confirmation procedure are described in detail in the Commission Decision 93/256/EC (CD). On the other hand, high resolution mass spectrometry (HRMS) is nowadays increasingly used for trace analysis. Yet its utility for confirmatory purposes has not been well explored and utilized, since established confirmation strategies like the CD do not yet include rules for modern HRMS technologies. It is the focus of this paper to evaluate the likelihood of false positive and false negative confirmation results, when using a variety of HRMS based measurement modes as compared to conventional QqQ mass spectrometry. The experimental strategy relies on the chromatographic separation of a complex blank sample (bovine liver extract) and the subsequent monitoring of a number of dummy transitions respectively dummy accurate masses. The term "dummy" refers to precursor and derived product ions (based on a realistic neutral loss) whose elemental compositions (CxHyNzOdCle) were produced by a random number generator. Monitoring a large number of such hypothetical SRM's, or accurate masses inevitably produces a number of mass traces containing chromatographic peaks (false detects) which are caused by eluting matrix compounds. The number and intensity of these peaks were recorded and standardized to permit a comparison among the two employed MS technologies. QqQ performance (compounds which happen to produce a response in two SRM traces at identical retention time) was compared with a number of different HRMS(1) and HRMS(2) detection based modes. A HRMS confirmation criterion based on two full scans (an unfragmented and an all ion fragmented) was proposed. Compared to the CD criteria, a significantly lower probability of false

  9. Fluxomics: mass spectrometry versus quantitative imaging

    PubMed Central

    Wiechert, Wolfgang; Schweissgut, Oliver; Takanaga, Hitomi; Frommer, Wolf B

    2010-01-01

    The recent development of analytic high-throughput technologies enables us to take a bird’s view of how metabolism is regulated in real time. We have known for a long time that metabolism is highly regulated at all levels, including transcriptional, posttranslational and allosteric controls. Flux through a metabolic or signaling pathway is determined by the activity of its individual components. Fluxomics aims to define the genes involved in regulation by following the flux. Two technologies are used to monitor fluxes. Pulse labeling of the organism or cell with a tracer, such as 13C, followed by mass spectrometric analysis of the partitioning of label into different compounds provides an efficient tool to study flux and to compare the effect of mutations on flux. The second approach is based on the use of flux sensors, proteins that respond with a conformational change to ligand binding. Fluorescence resonance energy transfer (FRET) detects the conformational change and serves as a proxy for ligand concentration. In contrast to the mass spectrometry assays, FRET nanosensors monitor only a single compound. Both methods provide high time resolution. The major advantages of FRET nanosensors are that they yield data with cellular and subcellular resolution and the method is minimally invasive. PMID:17481942

  10. Fluxomics: mass spectrometry versus quantitative imaging.

    PubMed

    Wiechert, Wolfgang; Schweissgut, Oliver; Takanaga, Hitomi; Frommer, Wolf B

    2007-06-01

    The recent development of analytic high-throughput technologies enables us to take a bird's view of how metabolism is regulated in real time. We have known for a long time that metabolism is highly regulated at all levels, including transcriptional, posttranslational and allosteric controls. Flux through a metabolic or signaling pathway is determined by the activity of its individual components. Fluxomics aims to define the genes involved in regulation by following the flux. Two technologies are used to monitor fluxes. Pulse labeling of the organism or cell with a tracer, such as 13C, followed by mass spectrometric analysis of the partitioning of label into different compounds provides an efficient tool to study flux and to compare the effect of mutations on flux. The second approach is based on the use of flux sensors, proteins that respond with a conformational change to ligand binding. Fluorescence resonance energy transfer (FRET) detects the conformational change and serves as a proxy for ligand concentration. In contrast to the mass spectrometry assays, FRET nanosensors monitor only a single compound. Both methods provide high time resolution. The major advantages of FRET nanosensors are that they yield data with cellular and subcellular resolution and the method is minimally invasive.

  11. Pushing the limits of accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Galindo-Uribarri, A.; Beene, J. R.; Danchev, M.; Doupé, J.; Fuentes, B.; Gomez del Campo, J.; Hausladen, P. A.; Juras, R. C.; Liang, J. F.; Litherland, A. E.; Liu, Y.; Meigs, M. J.; Mills, G. D.; Mueller, P. E.; Padilla-Rodal, E.; Pavan, J.; Sinclair, J. W.; Stracener, D. W.

    2007-06-01

    A renewed interest in Accelerator Mass Spectrometry (AMS) from nuclear physics laboratories is emerging in connection with Radioactive Ion Beams (RIBs). At the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) we are exploring the AMS capabilities of the 25-MV tandem accelerator. Behind this effort is the realization that two fields of research - AMS and RIBs - complement each other in techniques. Development of effective and efficient beam purification techniques is of common interest to both AMS and the RIB program. Two main characteristics of the 25-MV tandem provide unique opportunities for performing the highest sensitivity measurements of AMS; namely (i) the highest operating voltage in the world, and (ii) a folded geometry which involves a 180° magnet in the terminal. For the RIB program, we have used AMS techniques to improve the sensitivity of detection of some radioactive species in the measurement of unknown masses of n-rich nuclei. For AMS, we have concentrated in exploring two important isotopes, 14C and 36Cl, for applications that require the highest sensitivity. We have successfully measured 36Cl/Cl ratios as low as a few times 10-16 in seawater samples demonstrating that our setup has the highest sensitivity for this isotope and proving that 36Cl can be measured at the levels required for a tracer in oceanography.

  12. Multifunctional Carbon Fiber Ionization Mass Spectrometry.

    PubMed

    Wu, Meng-Xi; Wang, Hao-Yang; Zhang, Jun-Ting; Guo, Yin-Long

    2016-10-04

    A carbon fiber ionization (CFI) technique was developed for the mass spectrometric analysis of various organic compounds with different polarities. The design of the CFI technique was based on the good compatibility and dispersion of samples and solutions in different solvents on carbon fiber. As a fast, convenient, and versatile ionization method, CFI-MS is especially efficient for analyzing many low/nonpolar organic compounds, such as polycyclic aromatic hydrocarbons, long-chain aliphatic aldehydes, sensitive steroids, terpenoids, and organometallic compounds. Some of these compounds may not be well-analyzed by electrospray ionization or electron ionization mass spectrometry. On the basis of our experimental results, the major ion formation mechanism of CFI-MS was suggested to involve desorption in a steam-distillation-like process, and then, ionization occurred mainly via corona discharge under high voltage. CFI-MS could not only work alone but also be coupled with separation techniques. It works well when coupled with supercritical fluid chromatography (SFC) as well as in the analysis of exhaled human air. The high flexibility and versatility of CFI-MS has extended its applications in many areas, such as fast chemical screening, clinical testing, and forensic analysis.

  13. Mass spectrometry in bioinorganic analytical chemistry.

    PubMed

    Lobiński, Ryszard; Schaumlöffel, Dirk; Szpunar, Joanna

    2006-01-01

    A considerable momentum has recently been gained by in vitro and in vivo studies of interactions of trace elements in biomolecules due to advances in inductively coupled plasma mass spectrometry (ICP MS) used as a detector in chromatography and capillary and planar electrophoresis. The multi-isotopic (including non-metals such as S, P, or Se) detection capability, high sensitivity, tolerance to matrix, and large linearity range regardless of the chemical environment of an analyte make ICP MS a valuable complementary technique to electrospray MS and MALDI MS. This review covers different facets of the recent progress in metal speciation in biochemistry, including probing in vitro interactions between metals and biomolecules, detection, determination, and structural characterization of heteroatom-containing molecules in biological tissues, and protein monitoring and quantification via a heteroelement (S, Se, or P) signal. The application areas include environmental chemistry, plant and animal biochemistry, nutrition, and medicine. (c) 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:255-289, 2006.

  14. Chip-mass spectrometry for glycomic studies.

    PubMed

    Bindila, Laura; Peter-Katalinić, Jasna

    2009-01-01

    The introduction of micro- and nanochip front end technologies for electrospray mass spectrometry addressed a major challenge in carbohydrate analysis: high sensitivity structural determination and heterogeneity assessment in high dynamic range mixtures of biological origin. Chip-enhanced electrospray ionization was demonstrated to provide reproducible performance irrespective of the type of carbohydrate, while the amenability of chip systems for coupling with different mass spectrometers greatly advance the chip/MS technique as a versatile key tool in glycomic studies. A more accurate representation of the glycan repertoire to include novel biologically-relevant information was achieved in different biological sources, asserting this technique as a valuable tool in glycan biomarker discovery and monitoring. Additionally, the integration of various analytical functions onto chip devices and direct hyphenation to MS proved its potential for glycan analysis during the recent years, whereby a new analytical tool is on the verge of maturation: lab-on-chip MS glycomics. The achievements until early beginning of 2007 on the implementation of chip- and functional integrated chip/MS in systems glycobiology studies are reviewed here. (c) 2009 Wiley Periodicals, Inc.

  15. High Resolution Double-Focusing Isotope Ratio Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Radke, J.; Deerberg, M.; Hilkert, A.; Schlüter, H.-J.; Schwieters, J.

    2012-04-01

    In recent years isotope ratio mass spectrometry has extended to the capability of quantifying very small isotope signatures related with low abundances and simultaneously detecting molecular masses such as isotopomers and isotopologues containing clumped isotopes. Some of those applications are limited by molecular interferences like different gas molecules with the same nominal mass, e.g. Ar/O2, adducts of the same molecule or of different molecules, and very small isotope abundances. The Thermo Scientific MAT 253 ULTRA is the next generation of high precision gas isotope ratio mass spectrometry, which combines a 10 KV gas ionization source (Thermo Scientific MAT 253) with a double focusing multi-collector mass analyzer (Thermo Scientific Neptune) and reduces those limitations by measuring isotope ratios on a larger dynamic range with high precision. Small ion beam requirements and high sensitivity are achieved by signal-to-noise improvements through enhanced ion beam amplification in faraday cups and ion counters. Interfering backgrounds, e.g. interfering isotopologues or isobaric ions of contaminants, are dramatically decreased by a dynamic range increase combined with high evacuation leading to undisturbed ion transmission through the double-focusing analyser. Furthermore, automated gain calibration for mathematical baseline corrections, switchable detector arrays, ion source control, analyser focusing and full data export is controlled under Isodat data control. New reference/sample strategies are under investigation besides incorporation of the continuous-flow technique and its versatile inlet devices. We are presenting first results and applications of the MAT 253 Ultra.

  16. Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine

    SciTech Connect

    Annesley, Thomas M.; Cooks, Robert G.; Herold, David A.; Hoofnagle, Andrew N.

    2016-01-04

    Each year the journal Clinical Chemistry publishes a January special issue on a topic that is relevant to the laboratory medicine community. In January 2016 the topic is mass spectrometry, and the issue is entitled “Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine”. One popular feature in our issues is a Q&A on a topic, clearly in this case mass spectrometry. The journal is assembling a panel of 5-6 experts from various areas of mass spectrometry ranging from instrument manufacturing to practicing clinical chemists. Dick Smith is one of the scientist requested to participate in this special issue Q&A on Mass Spectrometry. The Q&A Transcript is attached

  17. US Food and Drug Administration Perspectives on Clinical Mass Spectrometry.

    PubMed

    Lathrop, Julia Tait; Jeffery, Douglas A; Shea, Yvonne R; Scholl, Peter F; Chan, Maria M

    2016-01-01

    Mass spectrometry-based in vitro diagnostic devices that measure proteins and peptides are underutilized in clinical practice, and none has been cleared or approved by the Food and Drug Administration (FDA) for marketing or for use in clinical trials. One way to increase their utilization is through enhanced interactions between the FDA and the clinical mass spectrometry community to improve the validation and regulatory review of these devices. As a reference point from which to develop these interactions, this article surveys the FDA's regulation of mass spectrometry-based devices, explains how the FDA uses guidance documents and standards in the review process, and describes the FDA's previous outreach to stakeholders. Here we also discuss how further communication and collaboration with the clinical mass spectrometry communities can identify opportunities for the FDA to provide help in the development of mass spectrometry-based devices and enhance their entry into the clinic.

  18. Photodegradation of organophosphorus insecticides - investigations of products and their toxicity using gas chromatography-mass spectrometry and AChE-thermal lens spectrometric bioassay.

    PubMed

    Bavcon Kralj, M; Franko, M; Trebse, P

    2007-02-01

    Four organophosphorus compounds: azinphos-methyl, chlorpyrifos, malathion and malaoxon in aqueous solution were degraded by using a 125 W xenon parabolic lamp. Gas chromatography-mass spectrometry (GC-MS) was used to monitor the disappearance of starting compounds and formation of degradation products as a function of time. AChE-thermal lens spectrometric bioassay was employed to assess the toxicity of photoproducts. The photodegradation kinetics can be described by a first-order degradation curve C=C0e(-kt), resulting in the following half lives: 2.5min for azinphos-methyl, 11.6 min for malathion, 13.3 min for chlorpyrifos and 45.5 min for malaoxon, under given experimental conditions. During the photoprocess several intermediates were identified by GC-MS suggesting the pathway of OP degradation. The oxidation of chlorpyrifos results in the formation of chlorpyrifos-oxon as the main identified photoproduct. In case of malathion and azinphos-methyl the corresponding oxon analogues were not detected. The formation of diethyl (dimethoxy-phosphoryl) succinate in traces was observed during photodegradation of malaoxon and malathion. Several other photoproducts including trimethyl phosphate esters, which are known to be AChE inhibitors and 1,2,3-benzotriazin-4(3H)-one as a member of triazine compounds were identified in photodegraded samples of malathion, malaoxon, and azinphos-methyl. Based on this, two main degradation pathways can be proposed, both result of the (P-S-C) bond cleavage taking place at the side of leaving group. The enhanced inhibition of AChE observed with the TLS bioassay during the initial 30 min of photodegradation in case of all four OPs, confirmed the formation of toxic intermediates. With the continuation of irradiation, the AChE inhibition decreased, indicating that the formed toxic compounds were further degraded to AChE non-inhibiting products. The presented results demonstrate the importance of toxicity monitoring during the degradation of

  19. Illustrating the Concepts of Isotopes and Mass Spectrometry in Introductory Courses: A MALDI-TOF Mass Spectrometry Laboratory Experiment

    ERIC Educational Resources Information Center

    Dopke, Nancy Carter; Lovett, Timothy Neal

    2007-01-01

    Mass spectrometry is a widely used and versatile tool for scientists in many different fields. Soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI) allow for the analysis of biomolecules, polymers, and clusters. This article describes a MALDI mass spectrometry experiment designed for students in introductory…

  20. Illustrating the Concepts of Isotopes and Mass Spectrometry in Introductory Courses: A MALDI-TOF Mass Spectrometry Laboratory Experiment

    ERIC Educational Resources Information Center

    Dopke, Nancy Carter; Lovett, Timothy Neal

    2007-01-01

    Mass spectrometry is a widely used and versatile tool for scientists in many different fields. Soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI) allow for the analysis of biomolecules, polymers, and clusters. This article describes a MALDI mass spectrometry experiment designed for students in introductory…

  1. Constraining Anthropogenic and Biogenic Emissions Using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Spencer, Kathleen M.

    Numerous gas-phase anthropogenic and biogenic compounds are emitted into the atmosphere. These gases undergo oxidation to form other gas-phase species and particulate matter. Whether directly or indirectly, primary pollutants, secondary gas-phase products, and particulate matter all pose health and environmental risks. In this work, ambient measurements conducted using chemical ionization mass spectrometry are used as a tool for investigating regional air quality. Ambient measurements of peroxynitric acid (HO2NO2) were conducted in Mexico City. A method of inferring the rate of ozone production, PO3, is developed based on observations of HO2NO 2, NO, and NO2. Comparison of this observationally based PO3 to a highly constrained photochemical box model indicates that regulations aimed at reducing ozone levels in Mexico City by reducing NOx concentrations may be effective at higher NO x levels than predicted using accepted photochemistry. Measurements of SO2 and particulate sulfate were conducted over the Los Angeles basin in 2008 and are compared to measurements made in 2002. A large decrease in SO2 concentration and a change in spatial distribution are observed. Nevertheless, only a modest reduction in sulfate concentration is observed at ground sites within the basin. Possible explanations for these trends are investigated. Two techniques, single and triple quadrupole chemical ionization mass spectrometry, were used to quantify ambient concentrations of biogenic oxidation products, hydroxyacetone and glycolaldehyde. The use of these techniques demonstrates the advantage of triple quadrupole mass spectrometry for separation of mass analogues, provided the collision-induced daughter ions are sufficiently distinct. Enhancement ratios of hydroxyacetone and glycolaldehyde in Californian biomass burning plumes are presented as are concentrations of these compounds at a rural ground site downwind of Sacramento.

  2. Novel Polyfluorinated Compounds Identified Using High Resolution Mass Spectrometry Downstream of Manufacturing Facilities near Decatur, Alabama

    EPA Science Inventory

    Concern over persistence, bioaccumulation, and toxicity has led to international regulation and phase-outs of certain perfluorinated compounds and little is known about their replacement products. High resolution mass spectrometry was used to investigate the occurrence and identi...

  3. Novel Polyfluorinated Compounds Identified Using High Resolution Mass Spectrometry Downstream of Manufacturing Facilities near Decatur, Alabama

    EPA Science Inventory

    Concern over persistence, bioaccumulation, and toxicity has led to international regulation and phase-outs of certain perfluorinated compounds and little is known about their replacement products. High resolution mass spectrometry was used to investigate the occurrence and identi...

  4. Neuropeptide Signaling in Crustaceans Probed by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liang, Zhidan

    Neuropeptides are one of the most diverse classes of signaling molecules whose identities and functions are not yet fully understood. They have been implicated in the regulation of a wide range of physiological processes, including feeding-related and motivated behaviors, and also environmental adaptations. In this work, improved mass spectrometry-based analytical platforms were developed and applied to the crustacean systems to characterize signaling molecules. This dissertation begins with a review of mass spectrometry-based neuropeptide studies from both temporal- and spatial-domains. This review is then followed by several chapters detailing a few research projects related to the crustacean neuropeptidomic characterization and comparative analysis. The neuropeptidome of crayfish, Orconectes rusticus is characterized for the first time using mass spectrometry-based tools. In vivo microdialysis sampling technique offers the capability of direct sampling from extracellular space in a time-resolved manner. It is used to investigate the secreted neuropeptide and neurotransmitter content in Jonah crab, Cancer borealis, in this work. A new quantitation strategy using alternative mass spectrometry data acquisition approach is developed and applied for the first time to quantify neuropeptides. Coupling of this method with microdialysis enables the study of neuropeptide dynamics concurrent with different behaviors. Proof-of-principle experiments validating this approach have been carried out in Jonah crab, Cancer borealis to study feeding- and circadian rhythm-related neuropeptide changes using micoridialysis in a time-resolved manner. This permits a close correlation between behavioral and neurochemical changes, providing potential candidates for future validation of regulatory roles. In addition to providing spatial information, mass spectrometry imaging (MSI) technique enables the characterization of signaling molecules while preserving the temporal resolution. A

  5. Mass Spectrometry Imaging: facts and perspectives from a non-mass spectrometrist point of view.

    PubMed

    Cameron, L C

    2012-08-01

    Mass Spectrometry Imaging (MSI, also called Imaging Mass Spectrometry) can be used to map molecules according to their chemical abundance and spatial distribution. This technique is not widely used in mass spectrometry circles and is barely known by other scientists. In this review, a brief overview of the mass spectrometer hardware used in MSI and some of the possible applications of this powerful technique are discussed. I intend to call attention to MSI uses from cell biology to histopathology for biological scientists who have little background in mass spectrometry. MSI facts and perspectives are presented from a non-mass spectrometrist point of view.

  6. Identification of Unknown Contaminants in Water Samples from ISS Employing Liquid Chromatography/Mass Spectrometry/Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Rutz, Jeffrey A.; Schultz, John R.

    2008-01-01

    Mass Spectrometry/Mass Spectrometry (MS/MS) is a powerful technique for identifying unknown organic compounds. For non-volatile or thermally unstable unknowns dissolved in liquids, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) is often the variety of MS/MS used for the identification. One type of LC/MS/MS that is rapidly becoming popular is time-of-flight (TOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of one unknown is reviewed in detail in this paper. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns.

  7. [Application of mass spectrometry to bacterial identification].

    PubMed

    Hernández, Álvaro Pascual; Ballestero-Téllez, Mónica; Galán-Sánchez, Fátima; Iglesias, Manuel Rodríguez

    2016-06-01

    Correct and rapid identification of bacteria is essential for the correct diagnosis and treatment of infected patients. Until a few years ago, biochemical, colorimetric or even antibiotic sensitivity tests were used to identify genera and species. The main limitations of these methods were the time needed for their performance and the difficulty of distinguishing between microorganisms that were little reactive, highly similar, or difficult to culture. Many of these problems have been solved by the introduction of mass spectrometry (MS) in the laboratory with the use of MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight). Knowledge of the strengths and weaknesses of this technology is essential to be able to take maximum advantage of this technique. Not all microorganisms can be identified with the same ease and reliability by MALDI-TOF and microbiologists need to know how to interpret the results obtained with this technique and the available alternatives in order to identify the microorganisms causing the most problems. This article aims to summarise the available information on the correct identification of the main human pathogenic bacteria through the use of MALDI-TOF MS, focusing on Gram-negative, Grampositive and anaerobic microorganisms. The main factors that must be taken into account for the reliable identification of any bacterium are the conditions for culture, sample preparation with the ideal extraction method and especially the use of a correct and updated database. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  8. Accelerator Mass Spectrometry in Laboratory Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Nusair, O.; Bauder, W.; Gyürky, G.; Paul, M.; Collon, P.; Fülöp, Zs; Greene, J.; Kinoshita, N.; Palchan, T.; Pardo, R.; Rehm, K. E.; Scott, R.; Vondrasek, R.

    2016-01-01

    The extreme sensitivity and discrimination power of accelerator mass spectrometry (AMS) allows for the search and the detection of rare nuclides either in natural samples or produced in the laboratory. At Argonne National Laboratory, we are developing an AMS setup aimed in particular at the detection of medium and heavy nuclides, relying on the high ion energy achievable with the ATLAS superconducting linear accelerator and on gas-filled magnet isobaric separation. The setup was recently used for the detection of the 146Sm p-process nuclide and for a new determination of the 146Sm half-life (68.7 My). AMS plays an important role in the measurement of stellar nuclear reaction cross sections by the activation method, extending thus the technique to the study of production of long-lived radionuclides. Preliminary measurements of the 147Sm(γ,n)146Sm are described. A measurement of the 142Nd(α,γ)146Sm and 142Nd(α,n)145Sm reactions is in preparation. A new laser-ablation method for the feeding of the Electron Cyclotron Resonance (ECR) ion source is described.

  9. Accelerator mass spectrometry of small biological samples.

    PubMed

    Salehpour, Mehran; Forsgard, Niklas; Possnert, Göran

    2008-12-01

    Accelerator mass spectrometry (AMS) is an ultra-sensitive technique for isotopic ratio measurements. In the biomedical field, AMS can be used to measure femtomolar concentrations of labeled drugs in body fluids, with direct applications in early drug development such as Microdosing. Likewise, the regenerative properties of cells which are of fundamental significance in stem-cell research can be determined with an accuracy of a few years by AMS analysis of human DNA. However, AMS nominally requires about 1 mg of carbon per sample which is not always available when dealing with specific body substances such as localized, organ-specific DNA samples. Consequently, it is of analytical interest to develop methods for the routine analysis of small samples in the range of a few tens of microg. We have used a 5 MV Pelletron tandem accelerator to study small biological samples using AMS. Different methods are presented and compared. A (12)C-carrier sample preparation method is described which is potentially more sensitive and less susceptible to contamination than the standard procedures.

  10. Secondary Ion Mass Spectrometry SIMS XI

    NASA Astrophysics Data System (ADS)

    Gillen, G.; Lareau, R.; Bennett, J.; Stevie, F.

    2003-05-01

    This volume contains 252 contributions presented as plenary, invited and contributed poster and oral presentations at the 11th International Conference on Secondary Ion Mass Spectrometry (SIMS XI) held at the Hilton Hotel, Walt Disney World Village, Orlando, Florida, 7 12 September, 1997. The book covers a diverse range of research, reflecting the rapid growth in advanced semiconductor characterization, ultra shallow depth profiling, TOF-SIMS and the new areas in which SIMS techniques are being used, for example in biological sciences and organic surface characterization. Papers are presented under the following categories: Isotopic SIMS Biological SIMS Semiconductor Characterization Techniques and Applications Ultra Shallow Depth Profiling Depth Profiling Fundamental/Modelling and Diffusion Sputter-Induced Topography Fundamentals of Molecular Desorption Organic Materials Practical TOF-SIMS Polyatomic Primary Ions Materials/Surface Analysis Postionization Instrumentation Geological SIMS Imaging Fundamentals of Sputtering Ion Formation and Cluster Formation Quantitative Analysis Environmental/Particle Characterization Related Techniques These proceedings provide an invaluable source of reference for both newcomers to the field and experienced SIMS users.

  11. JAMSS: proteomics mass spectrometry simulation in Java.

    PubMed

    Smith, Rob; Prince, John T

    2015-03-01

    Countless proteomics data processing algorithms have been proposed, yet few have been critically evaluated due to lack of labeled data (data with known identities and quantities). Although labeling techniques exist, they are limited in terms of confidence and accuracy. In silico simulators have recently been used to create complex data with known identities and quantities. We propose Java Mass Spectrometry Simulator (JAMSS): a fast, self-contained in silico simulator capable of generating simulated MS and LC-MS runs while providing meta information on the provenance of each generated signal. JAMSS improves upon previous in silico simulators in terms of its ease to install, minimal parameters, graphical user interface, multithreading capability, retention time shift model and reproducibility. The simulator creates mzML 1.1.0. It is open source software licensed under the GPLv3. The software and source are available at https://github.com/optimusmoose/JAMSS. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. 3D Imaging by Mass Spectrometry: A New Frontier

    PubMed Central

    Seeley, Erin H.; Caprioli, Richard M.

    2012-01-01

    Summary Imaging mass spectrometry can generate three-dimensional volumes showing molecular distributions in an entire organ or animal through registration and stacking of serial tissue sections. Here we review the current state of 3D imaging mass spectrometry as well as provide insights and perspectives on the process of generating 3D mass spectral data along with a discussion of the process necessary to generate a 3D image volume. PMID:22276611

  13. Mass spectrometry of Natural Products: Current, Emerging and Future Technologies

    PubMed Central

    Bouslimani, Amina; Sanchez, Laura M; Garg, Neha; Dorrestein, Pieter C

    2014-01-01

    Although mass spectrometry is a century old technology, we are entering into an exciting time for the analysis of molecular information directly from complex biological systems. In this viewpoint article, we highlight emerging mass spectrometric methods and tools used by the natural product community and give a perspective of future directions where the mass spectrometry field is migrating towards over the next decade. PMID:24801551

  14. Application of accelerator mass spectrometry in aluminum metabolism studies

    NASA Astrophysics Data System (ADS)

    Meirav, O.; Sutton, R. A. L.; Fink, D.; Middleton, R.; Klein, J.; Walker, V. R.; Halabe, A.; Vetterli, D.; Johnson, R. R.

    1990-12-01

    The recent recognition that aluminum causes toxicity in uremie patients and may be associated with Alzheimer's disease has stimulated many studies of its biochemical effects. However, such studies were hampered by the lack of a suitable tracer. In a novel experiment, we have applied the new technique of accelerator mass spectrometry to investigate aluminum kinetics in rats, using as a marker the long-lived isotope 26Al. We present the first aluminum kinetic model for a biological system. The results clearly demonstrate the advantage this technique holds for isotope tracer studies in animals as well as in humans.

  15. Epidemiological typing of Klebsiella pneumoniae by pyrolysis mass spectrometry.

    PubMed

    Jackson, R M; Heginbothom, M L; Magee, J T

    1997-01-01

    Thirteen isolates of ceftazidime-resistant Klebsiella pneumoniae from a suspected cross-infection outbreak involving patients on an intensive care unit and a haematology ward were examined in pyrolysis-mass spectrometry (Py-MS), along with eight concurrent non-outbreak-associated clinical isolates of klebsiellae as controls. Py-MS showed tight clustering of the suspected outbreak isolates, suggesting cross-infection with a single strain. Non-outbreak isolates were clearly distinct from one another and from the outbreak strain. The results confirm that Py-MS is a powerful tool for rapid strain comparison in investigations of cross-infection incidents.

  16. Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products

    NASA Astrophysics Data System (ADS)

    Es-Safi, Nour-Eddine; Essassi, El Mokhtar; Massoui, Mohamed; Banoub, Joseph

    Mass spectrometry is an important tool for the identification and structural elucidation of natural and synthesized compounds. Its high sensitivity and the possibility of coupling liquid chromatography with mass spectrometry detection make it a technique of choice for the investigation of complex mixtures like raw natural extracts. The mass spectrometer is a universal detector that can achieve very high sensitivity and provide information on the molecular mass. More detailed information can be subsequently obtained by resorting to collision-induced dissociation tandem mass spectrometry (CID-MS/MS). In this review, the application of mass spectrometric techniques for the identification of natural and synthetic compounds is presented. The gas-phase fragmentation patterns of a series of four natural flavonoid glycosides, three synthesized benzodiazepines and two synthesized quinoxalinone derivatives were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry techniques. Exact accurate masses were measured using a modorate resolution quadrupole orthogonal time-of-flight QqTOF-MS/MS hybrid mass spectrometer instrument. Confirmation of the molecular masses and the chemical structures of the studied compounds were achieved by exploring the gas-phase breakdown routes of the ionized molecules. This was rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole hexapole-quadrupole (QhQ) tandem mass spectrometer.

  17. Analysis of perchlorate in groundwater by electrospray ionization mass spectrometry/mass spectrometry

    SciTech Connect

    Koester, C.J.; Beller, H.R.; Halden, R.U.

    2000-05-01

    An electrospray ionization mass spectrometry/mass spectrometry (ESI/MS/MS) method was developed to measure part-per-billion ({micro}g/L) concentrations of perchlorate in groundwater. Selective and sensitive perchlorate detection was achieved by operating the mass spectrometer in the negative ionization mode and by using MS/MS to monitor the CIO{sub 4}{sup {minus}} to ClO{sub 3}{sup {minus}} transition. The method of standard additions was used to address the considerable signal suppression caused by anions that are typically present in groundwater, such as bicarbonate and sulfate. ESI-MS/MS analysis was rapid, accurate, reproducible, and provided a detection limit of 0.5 {micro}g/L perchlorate in groundwater. Accuracy and precision of the ESI/MS/MS method were assessed by analyzing performance evaluation samples in a groundwater matrix and by comparing ion chromatography (IC) and ESI/MS/MS results for local groundwater samples. Results for the performance evaluation samples differed from the certified values by 4--13%, and precision ranged from 3 to 10% (relative standard deviation). The IC and ESI/MS/MS results were statistically indistinguishable for perchlorate concentrations above the detection limits of both methods.

  18. Characterization of Membrane Protein-Lipid Interactions by Mass Spectrometry Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Cong, Xiao; Liu, Wen; Laganowsky, Arthur

    2017-04-01

    Lipids in the biological membrane can modulate the structure and function of integral and peripheral membrane proteins. Distinguishing individual lipids that bind selectively to membrane protein complexes from an ensemble of lipid-bound species remains a daunting task. Recently, ion mobility mass spectrometry (IM-MS) has proven to be invaluable for interrogating the interactions between protein and individual lipids, where the complex undergoes collision induced unfolding followed by quantification of the unfolding pathway to assess the effect of these interactions. However, gas-phase unfolding experiments for membrane proteins are typically performed on the entire ensemble ( apo and lipid bound species), raising uncertainty to the contribution of individual lipids and the species that are ejected in the unfolding process. Here, we describe the application of mass spectrometry ion mobility mass spectrometry (MS-IM-MS) for isolating ions corresponding to lipid-bound states of a model integral membrane protein, ammonia channel (AmtB) from Escherichia coli. Free of ensemble effects, MS-IM-MS reveals that bound lipids are ejected as neutral species; however, no correlation was found between the lipid-induced stabilization of complex and their equilibrium binding constants. In comparison to data obtained by IM-MS, there are surprisingly limited differences in stability measurements from IM-MS and MS-IM-MS. The approach described here to isolate ions of membrane protein complexes will be useful for other MS methods, such as surface induced dissociation or collision induced dissociation to determine the stoichiometry of hetero-oligomeric membrane protein complexes.

  19. Characterization of Membrane Protein-Lipid Interactions by Mass Spectrometry Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Cong, Xiao; Liu, Wen; Laganowsky, Arthur

    2016-12-01

    Lipids in the biological membrane can modulate the structure and function of integral and peripheral membrane proteins. Distinguishing individual lipids that bind selectively to membrane protein complexes from an ensemble of lipid-bound species remains a daunting task. Recently, ion mobility mass spectrometry (IM-MS) has proven to be invaluable for interrogating the interactions between protein and individual lipids, where the complex undergoes collision induced unfolding followed by quantification of the unfolding pathway to assess the effect of these interactions. However, gas-phase unfolding experiments for membrane proteins are typically performed on the entire ensemble (apo and lipid bound species), raising uncertainty to the contribution of individual lipids and the species that are ejected in the unfolding process. Here, we describe the application of mass spectrometry ion mobility mass spectrometry (MS-IM-MS) for isolating ions corresponding to lipid-bound states of a model integral membrane protein, ammonia channel (AmtB) from Escherichia coli. Free of ensemble effects, MS-IM-MS reveals that bound lipids are ejected as neutral species; however, no correlation was found between the lipid-induced stabilization of complex and their equilibrium binding constants. In comparison to data obtained by IM-MS, there are surprisingly limited differences in stability measurements from IM-MS and MS-IM-MS. The approach described here to isolate ions of membrane protein complexes will be useful for other MS methods, such as surface induced dissociation or collision induced dissociation to determine the stoichiometry of hetero-oligomeric membrane protein complexes.

  20. Application of comprehensive two-dimensional gas chromatography mass spectrometry and different types of data analysis for the investigation of cigarette particulate matter.

    PubMed

    Gröger, Thomas; Welthagen, Werner; Mitschke, Stefan; Schäffer, Marion; Zimmermann, Ralf

    2008-10-01

    In tobacco research, the comparison of different tobacco blends as well as the puff-dependent behaviour of cigarettes is a matter of particular interest. For the investigation of smoke characteristics, GC x GC offers different ways for data analysis, namely, compound target analysis, automated peak-based compound classification and comprehensive pixel-based data analysis. This study will show the application as well as the pros and cons of these types of data analysis for very complex matrices like cigarette particulate matter. In addition, new aspects about the recently discovered puff-dependent behaviour of compounds in cigarette smoke will be presented. Automated peak-based compound classification including mass spectrometric pattern recognition is used for the classification of tobacco particulate matter samples and the puff-dependent investigation of different compound classes. This compound group specific analysis is further reinforced by applying an even more comprehensive pixel-based analysis. This kind of analysis is used to generate fingerprints of different types of cigarettes. The combination of fast feature reduction methods like analysis of variance (ANOVA) and t-test with multivariate feature transformation methods like partial least squares discriminate analysis (PLSDA) for feature selection provides a powerful tool for a detailed inspection of different types of cigarettes.

  1. Intact MicroRNA Analysis Using High Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Kullolli, Majlinda; Knouf, Emily; Arampatzidou, Maria; Tewari, Muneesh; Pitteri, Sharon J.

    2014-01-01

    MicroRNAs (miRNAs) are small single-stranded non-coding RNAs that post-transcriptionally regulate gene expression, and play key roles in the regulation of a variety of cellular processes and in disease. New tools to analyze miRNAs will add understanding of the physiological origins and biological functions of this class of molecules. In this study, we investigate the utility of high resolution mass spectrometry for the analysis of miRNAs through proof-of-concept experiments. We demonstrate the ability of mass spectrometry to resolve and separate miRNAs and corresponding 3' variants in mixtures. The mass accuracy of the monoisotopic deprotonated peaks from various miRNAs is in the low ppm range. We compare fragmentation of miRNA by collision-induced dissociation (CID) and by higher-energy collisional dissociation (HCD) which yields similar sequence coverage from both methods but additional fragmentation by HCD versus CID. We measure the linear dynamic range, limit of detection, and limit of quantitation of miRNA loaded onto a C18 column. Lastly, we explore the use of data-dependent acquisition of MS/MS spectra of miRNA during online LC-MS and demonstrate that multiple charge states can be fragmented, yielding nearly full sequence coverage of miRNA on a chromatographic time scale. We conclude that high resolution mass spectrometry allows the separation and measurement of miRNAs in mixtures and a standard LC-MS setup can be adapted for online analysis of these molecules.

  2. Intact MicroRNA Analysis Using High Resolution Mass Spectrometry

    PubMed Central

    Kullolli, Majlinda; Knouf, Emily; Arampatzidou, Maria; Tewari, Muneesh; Pitteri, Sharon J.

    2014-01-01

    MicroRNAs (miRNAs) are small single-stranded non-coding RNAs that post-transcriptionally regulate gene expression, and play key roles in the regulation of a variety of cellular processes and in disease. New tools to analyze miRNAs will add understanding of the physiological origins and biological functions of this class of molecules. In this study we investigate the utility of high resolution mass spectrometry for the analysis of miRNAs through proof-of-concept experiments. We demonstrate the ability of mass spectrometry to resolve and separate miRNAs and corresponding 3′ variants in mixtures. The mass accuracy of the monoisotopic deprotonated peaks from various miRNAs is in the low ppm range. We compare fragmentation of miRNA by collision-induced dissociation (CID) and by higher-energy collisional dissociation (HCD) which yields similar sequence coverage from both methods but additional fragmentation by HCD versus CID. We measure the linear dynamic range, limit of detection, and limit of quantitation of miRNA loaded onto a C18 column. Lastly we explore the use of data dependent acquisition of MS/MS spectra of miRNA during online LC-MS and demonstrate that multiple charge states can be fragmented, yielding nearly full sequence coverage of miRNA on a chromatographic time scale. We conclude that high resolution mass spectrometry allows the separation and measurement of miRNAs in mixtures and a standard LC-MS setup can be adapted for online analysis of these molecules. PMID:24174127

  3. Molecular mass spectrometry imaging in biomedical and life science research.

    PubMed

    Pól, Jaroslav; Strohalm, Martin; Havlíček, Vladimír; Volný, Michael

    2010-11-01

    This review describes the current state of mass spectrometry imaging (MSI) in life sciences. A brief overview of mass spectrometry principles is presented followed by a thorough introduction to the MSI workflows, principles and areas of application. Three major desorption-ionization techniques used in MSI, namely, secondary ion mass spectrometry (SIMS), matrix-assisted laser desorption ionization (MALDI), and desorption electrospray ionization (DESI) are described, and biomedical and life science imaging applications of each ionization technique are reviewed. A separate section is devoted to data handling and current challenges and future perspectives are briefly discussed at the end.

  4. Investigation of the transformation of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol during water chlorination by liquid chromatography-quadrupole-time-of-flight-mass spectrometry.

    PubMed

    González-Mariño, Iria; Rodríguez, Isaac; Quintana, José Benito; Cela, Rafael

    2013-10-15

    The stability of the main metabolite of cannabis, (±)-11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH), during water chlorination has been investigated. THCCOOH was degraded in few seconds following a pseudo-first order kinetics. Sample pH turned out to be a significant factor, decreasing THCCOOH half-life with an increase in its values. Seven by-products could be positively identified from accurate mass measurements: three compounds resulted from electrophilic substitutions of hydrogen per chlorine (or bromine) in the aromatic ring, whereas the formation of the remaining four involved additional reactions in the C-C double bond (hydration and halogenation). The software predicted toxicity of these products towards Daphnia magna indicates that they are expected to have toxicity values similar or higher than its precursor compound. Experiments conducted with diluted urine showed that THCCOOH was stable in this matrix, probably due to a rapid and complete reaction between chlorine and other organic constituents already present in the samples. In real surface waters, the extent of the reaction was also affected by the organic matter content, and so THCCOOH was rapidly degraded in samples scarcely affected by human activities, being more stable in waters with a higher level of pollution.

  5. Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting.

    PubMed

    Senyuva, Hamide Z; Gökmen, Vural

    2005-03-01

    An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500?microg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225 degrees C. Change in the CIE (Commission Internationale de l'Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.

  6. First application of mass spectrometry and gas chromatography in investigation of α-cellulose hydrolysates: the influence of climate changes on glucose molecules in pine tree-rings.

    PubMed

    Sensuła, Barbara M; Pazdur, Anna; Marais, Marie-France

    2011-02-28

    We present the first results of the quantitative and qualitative gas chromatographic and isotope ratio mass spectrometric analysis of monosaccharides derived from acid hydrolysis of α-cellulose extracted from annual pine tree-rings. The conifers investigated in this study grew in the Niepolomice Forest in Poland, and the annual rings covered the time span from 1940 to 2000 AD. The main components of the α-cellulose samples were two saccharides: glucose and mannose. The amount of glucose in the annual rings varied between 17 and 44%. The δ(13)C of glucose was found to be less negative than that of α-cellulose and the δ(18)O values in glucose were less positive than those in α-cellulose. The content of monosaccharides in the α-cellulose samples has an influence on the isotope fractionation factors. The values of the carbon isotope fractionation factor increase with an increase in the monosaccharides concentration in α-cellulose, while the values of the oxygen isotope fractionation factor decrease with an increase in monosaccharides concentration in α-cellulose. The challenge is to establish, with respect to climate changes and environmental conditions, the significance of the interannual variations in the observed monosaccharide concentration.

  7. imzML: Imaging Mass Spectrometry Markup Language: A common data format for mass spectrometry imaging.

    PubMed

    Römpp, Andreas; Schramm, Thorsten; Hester, Alfons; Klinkert, Ivo; Both, Jean-Pierre; Heeren, Ron M A; Stöckli, Markus; Spengler, Bernhard

    2011-01-01

    Imaging mass spectrometry is the method of scanning a sample of interest and generating an "image" of the intensity distribution of a specific analyte. The data sets consist of a large number of mass spectra which are usually acquired with identical settings. Existing data formats are not sufficient to describe an MS imaging experiment completely. The data format imzML was developed to allow the flexible and efficient exchange of MS imaging data between different instruments and data analysis software.For this purpose, the MS imaging data is divided in two separate files. The mass spectral data is stored in a binary file to ensure efficient storage. All metadata (e.g., instrumental parameters, sample details) are stored in an XML file which is based on the standard data format mzML developed by HUPO-PSI. The original mzML controlled vocabulary was extended to include specific parameters of imaging mass spectrometry (such as x/y position and spatial resolution). The two files (XML and binary) are connected by offset values in the XML file and are unambiguously linked by a universally unique identifier. The resulting datasets are comparable in size to the raw data and the separate metadata file allows flexible handling of large datasets.Several imaging MS software tools already support imzML. This allows choosing from a (growing) number of processing tools. One is no longer limited to proprietary software, but is able to use the processing software which is best suited for a specific question or application. On the other hand, measurements from different instruments can be compared within one software application using identical settings for data processing. All necessary information for evaluating and implementing imzML can be found at http://www.imzML.org .

  8. The allure of mass spectrometry: From an earlyday chemist's perspective.

    PubMed

    Tőkés, László

    2017-07-01

    This reminiscing review article is an account of the author's fascination and involvements with mass spectrometry from the perspective of an organic chemist with an interest in natural product chemistry. It covers a period from 1961 through the mid 1990s as mass spectrometry evolved form a novelty technique to become a most widely used analytical technique. Following a brief synopsis of my pathway to mass spectrometry, my research efforts in this field are presented with a focus mainly on evolving principles and technologies which I had personal involvements with. To provide historical perspectives, discussions of these developments are accompanied by brief outlines of the relevant state-of-the-art, shedding light on the technical and conceptual challenges encountered during those early days in mass spectrometry. Examples are presented of my involvements with basic and applied research in mass spectrometry during graduate studies at Stanford University and close to three decade tenure in pharmaceutical research at Syntex Research. My basic research interests focused mainly on principles of electron ionization induced fragmentation mechanisms, with an emphasis on steroids and other model compounds. Extensive deuterium labeling evidence was used to determine the fragmentation mechanisms of the diagnostically significant ions in the spectra of numerous model compounds, uncovering examples of wide-ranging hydrogen transfers, skeletal rearrangements, methyl and phenyl migrations, stereoselective fragmentations and low and high energy fragmentation processes. Depiction of the industrial research phase of my career includes comments on the pivotal role mass spectrometry played on advancing modern pharmaceutical research. Examples are presented of involvements with instrumental developments and a few select cases of applied research, including studies of bile mechanisms in vertebrates, identification of bisphenol-A leaching from sterilized polycarbonate containers, high

  9. Calcium isotope analysis by mass spectrometry.

    PubMed

    Boulyga, Sergei F

    2010-01-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of (41)Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use

  10. Optical mass memory investigation

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The MASTER 1 optical mass storage system advanced working model (AWM) was designed to demonstrate recording and playback of imagery data and to enable quantitative data to be derived as to the statistical distribution of raw errors experienced through the system. The AWM consists of two subsystems, the recorder and storage and retrieval. The recorder subsystem utilizes key technologies such as an acoustic travelling wave lens to achieve recording of digital data on fiche at a rate of 30 Mbits/sec, whereas the storage and retrieval reproducer subsystem utilizes a less complex optical system that employs an acousto-optical beam deflector to achieve data readout at a 5 Mbits/sec rate. The system has the built in capability for detecting and collecting error statistics. The recorder and storage and retrieval subsystems operate independent of one another and are each constructed in modular form with each module performing independent functions. The operation of each module and its interface to other modules is controlled by one controller for both subsystems.

  11. Protein Quantitation of the Developing Cochlea Using Mass Spectrometry.

    PubMed

    Darville, Lancia N F; Sokolowski, Bernd H A

    2016-01-01

    Mass spectrometry-based proteomics allows for the measurement of hundreds to thousands of proteins in a biological system. Additionally, mass spectrometry can also be used to quantify proteins and peptides. However, observing quantitative differences between biological systems using mass spectrometry-based proteomics can be challenging because it is critical to have a method that is fast, reproducible, and accurate. Therefore, to study differential protein expression in biological samples labeling or label-free quantitative methods can be used. Labeling methods have been widely used in quantitative proteomics, however label-free methods have become equally as popular and more preferred because they produce faster, cleaner, and simpler results. Here, we describe the methods by which proteins are isolated and identified from cochlear sensory epithelia tissues at different ages and quantitatively differentiated using label-free mass spectrometry.

  12. Molecular Beam Mass Spectrometry (MBMS) (Revised) (Fact Sheet)

    SciTech Connect

    Not Available

    2011-07-01

    This fact sheet provides information about Molecular Beam Mass Spectrometry (MBMS) capabilities and applications at NREL's National Bioenergy Center. NREL has six MBMS systems that researchers and industry partners can use to understand thermochemical biomass conversion and biomass composition recalcitrance.

  13. Laser mass spectrometry for DNA sequencing, disease diagnosis, and fingerprinting

    NASA Astrophysics Data System (ADS)

    Chen, C. H. Winston; Taranenko, N. I.; Zhu, Y. F.; Chung, C. N.; Allman, S. L.

    1997-05-01

    Since laser mass spectrometry has the potential for achieving very fast DNA analysis, we recently applied it to DNA sequencing, DNA typing for fingerprinting, and DNA screening for disease diagnosis. Two different approaches for sequencing DNA have been successfully demonstrated. One is to sequence DNA with DNA ladders produced from Sanger's enzymatic method. The other is to do direct sequencing without DNA ladders. The need for quick DNA typing for identification purposes is critical for forensic application. Our preliminary results indicate laser mass spectrometry can possible be used for rapid DNA fingerprinting applications at a much lower cost than gel electrophoresis. Population screening for certain genetic disease can be a very efficient step to reducing medical costs through prevention. Since laser mass spectrometry can provide very fast DNA analysis, we applied laser mass spectrometry to disease diagnosis. Clinical samples with both base deletion and point mutation have been tested with complete success.

  14. Laser mass spectrometry for DNA sequencing, disease diagnosis, and fingerprinting

    SciTech Connect

    Winston Chen, C.H.; Taranenko, N.I.; Zhu, Y.F.; Chung, C.N.; Allman, S.L.

    1997-03-01

    Since laser mass spectrometry has the potential for achieving very fast DNA analysis, the authors recently applied it to DNA sequencing, DNA typing for fingerprinting, and DNA screening for disease diagnosis. Two different approaches for sequencing DNA have been successfully demonstrated. One is to sequence DNA with DNA ladders produced from Snager`s enzymatic method. The other is to do direct sequencing without DNA ladders. The need for quick DNA typing for identification purposes is critical for forensic application. The preliminary results indicate laser mass spectrometry can possibly be used for rapid DNA fingerprinting applications at a much lower cost than gel electrophoresis. Population screening for certain genetic disease can be a very efficient step to reducing medical costs through prevention. Since laser mass spectrometry can provide very fast DNA analysis, the authors applied laser mass spectrometry to disease diagnosis. Clinical samples with both base deletion and point mutation have been tested with complete success.

  15. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues (2010 Review)

    EPA Science Inventory

    This biennial review covers developments in environmental mass spectrometry for emerging environmental contaminants over the period of 2008-2009. A few significant references that appeared between January and February 2010 are also included. Analytical Chemistry’s current polic...

  16. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues, 2008 Review

    EPA Science Inventory

    This biennial review covers developments in Environmental Mass Spectrometry for Emerging Environmental Contaminants over the period of 2006-2007. A few significant references that appeared between January and February 2008 are also included. Analytical Chemistry’s current polic...

  17. Mass Spectrometry of Membrane Proteins: A Focus on Aquaporins

    PubMed Central

    Schey, Kevin L.; Grey, Angus C.; Nicklay, Joshua J.

    2015-01-01

    Membrane proteins are abundant, critically important biomolecules that conduct essential functions in all cells and are the targets of a significant number of therapeutic drugs. However, the analysis of their expression, modification, protein–protein interactions, and structure by mass spectrometry has lagged behind similar studies of soluble proteins. Here we review the limitations to analysis of integral membrane and membrane-associated proteins and highlight advances in sample preparation and mass spectrometry methods that have led to the successful analysis of this protein class. Advances in the analysis of membrane protein posttranslational modification, protein–protein interaction, protein structure, and tissue distributions by imaging mass spectrometry are discussed. Furthermore, we focus our discussion on the application of mass spectrometry for the analysis of aquaporins as a prototypical integral membrane protein and how advances in analytical methods have revealed new biological insights into the structure and function of this family of proteins. PMID:23394619

  18. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues (2010 Review)

    EPA Science Inventory

    This biennial review covers developments in environmental mass spectrometry for emerging environmental contaminants over the period of 2008-2009. A few significant references that appeared between January and February 2010 are also included. Analytical Chemistry’s current polic...

  19. Recent applications of mass spectrometry in forensic toxicology

    NASA Astrophysics Data System (ADS)

    Foltz, Rodger L.

    1992-09-01

    This review encompasses applications of mass spectrometry reported during the years 1989, 1990 and 1991 for the analysis of cannabinoids, cocaine, opiates, amphetamines, lysergic acid diethylamide (LSD), and their metabolites in physiological specimens.

  20. Mass spectrometry of membrane proteins: a focus on aquaporins.

    PubMed

    Schey, Kevin L; Grey, Angus C; Nicklay, Joshua J

    2013-06-04

    Membrane proteins are abundant, critically important biomolecules that conduct essential functions in all cells and are the targets of a significant number of therapeutic drugs. However, the analysis of their expression, modification, protein-protein interactions, and structure by mass spectrometry has lagged behind similar studies of soluble proteins. Here we review the limitations to analysis of integral membrane and membrane-associated proteins and highlight advances in sample preparation and mass spectrometry methods that have led to the successful analysis of this protein class. Advances in the analysis of membrane protein posttranslational modification, protein-protein interaction, protein structure, and tissue distributions by imaging mass spectrometry are discussed. Furthermore, we focus our discussion on the application of mass spectrometry for the analysis of aquaporins as a prototypical integral membrane protein and how advances in analytical methods have revealed new biological insights into the structure and function of this family of proteins.

  1. Photodissociation mass spectrometry: New tools for characterization of biological molecules

    PubMed Central

    Brodbelt, Jennifer S.

    2014-01-01

    Photodissociation mass spectrometry combines the ability to activate and fragment ions using photons with the sensitive detection of the resulting product ions by mass spectrometry. The resulting combination affords a versatile tool for characterization of biological molecules. The scope and breadth of photodissociation mass spectrometry have increased substantially over the past decade as new research groups have entered the field and developed a number of innovative applications that illustrate the ability of photodissociation to produce rich fragmentation patterns, to cleave bonds selectively, and to target specific molecules based on incorporation of chromophores. This review focuses on many of the key developments in photodissociation mass spectrometry over the past decade with a particular emphasis on its applications to biological molecules. PMID:24481009

  2. THE APPLICATION OF MASS SPECTROMETRY TO THE STUDY OF MICROORGANISMS

    EPA Science Inventory

    The purpose of this research project is to use state-of-the-art mass spectrometric techniques, such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS), to provide "protein mass fingerprinting" and protein sequencing i...

  3. THE APPLICATION OF MASS SPECTROMETRY TO THE STUDY OF MICROORGANISMS

    EPA Science Inventory

    The purpose of this research project is to use state-of-the-art mass spectrometric techniques, such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS), to provide "protein mass fingerprinting" and protein sequencing i...

  4. A purge and trap technique to capture volatile compounds combined with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry to investigate the effect of sulfur-fumigation on Radix Angelicae Dahuricae.

    PubMed

    Cao, Gang; Li, Qinglin; Zhang, Jida; Cai, Hao; Cai, Baochang

    2014-09-01

    Sulfur-fumigation is known to reduce volatile compounds that are the main active components in herbs used in herbal medicine. We investigated changes in chemical composition between sun-dried and sulfur-fumigated Radix Angelicae Dahuricae using a purge and trap technique to capture volatile compounds, and two-dimensional gas chromatography/time-of-flight mass spectrometry for identification. Using sun-dried Radix Angelicae Dahuricae samples as a reference, the results showed that 73 volatile compounds, including 12 sulfide compounds, were found to be present only in sulfur-fumigated samples. Furthermore, 32 volatile compounds that were found in sun-dried Radix Angelicae Dahuricae samples disappeared after sulfur-fumigation. The proposed method can be applied to accurately discriminate sulfur-fumigated Radix Angelicae Dahuricae from different commercial sources.

  5. Simultaneous enantioselective separation of azelastine and three of its metabolites for the investigation of the enantiomeric metabolism in rats. I. Liquid chromatography-ionspray tandem mass spectrometry and electrokinetic capillary chromatography.

    PubMed

    Heinemann, Ute; Blaschke, Gottfried; Knebel, Norbert

    2003-08-15

    Enantioselective separation methods and the enantioselective determination of the anti-allergic drug azelastine and of three of its main phase I metabolites in a biological matrix underwent chromatographic and electrophoretic investigations. An enantioselective assay of a coupling of HPLC using a beta-cyclodextrin chiral stationary phase to ionspray tandem mass spectrometry is presented. Additionally, this assay is compared to another enantioselective assay using electrokinetic capillary chromatography with beta-cyclodextrin and carboxymethyl-beta-cyclodextrin in polyacrylamide-coated capillaries. For capillary electrophoresis (CE) the importance of polyacrylamide coating for the validation of this separation method is highlighted. Extracted rat plasma samples of enantioselective metabolism studies were measured by both validated assays. Differences in the pharmacokinetics and pharmacodynamics were evaluated for the main substance azelastine and its main metabolite demethylazelastine. So, a first hint about the enantioselectivity of biotransformation of azelastine in rats was seen after oral application of either enantiomer or the racemate to rats.

  6. Mass Spectrometry of Protein Complexes: From Origins to Applications

    NASA Astrophysics Data System (ADS)

    Mehmood, Shahid; Allison, Timothy M.; Robinson, Carol V.

    2015-04-01

    Now routine is the ability to investigate soluble and membrane protein complexes in the gas phase of a mass spectrometer while preserving folded structure and ligand-binding properties. Several recent transformative developments have occurred to arrive at this point. These include advances in mass spectrometry instrumentation, particularly with respect to resolution; the ability to study intact membrane protein complexes released from detergent micelles; and the use of protein unfolding in the gas phase to obtain stability parameters. Together, these discoveries are providing unprecedented information on the compositional heterogeneity of biomacromolecules, the unfolding trajectories of multidomain proteins, and the stability imparted by ligand binding to both soluble and membrane-embedded protein complexes. We review these recent breakthroughs, highlighting the challenges that had to be overcome and the physicochemical insight that can now be gained from studying proteins and their assemblies in the gas phase.

  7. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

    PubMed Central

    Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

    2016-01-01

    The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions. PMID:28042492

  8. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells.

    PubMed

    Johánek, Viktor; Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

    2016-01-01

    The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

  9. Calcium Isotope Analysis by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Boulyga, S.; Richter, S.

    2010-12-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. This presentation discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. Additionally, the availability of Ca isotope reference materials will be discussed.

  10. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    DOEpatents

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  11. Analysis of chirality by femtosecond laser ionization mass spectrometry.

    PubMed

    Horsch, Philipp; Urbasch, Gunter; Weitzel, Karl-Michael

    2012-09-01

    Recent progress in the field of chirality analysis employing laser ionization mass spectrometry is reviewed. Emphasis is given to femtosecond (fs) laser ionization work from the author's group. We begin by reviewing fundamental aspects of determining circular dichroism (CD) in fs-laser ionization mass spectrometry (fs-LIMS) discussing an example from the literature (resonant fs-LIMS of 3-methylcyclopentanone). Second, we present new data indicating CD in non-resonant fs-LIMS of propylene oxide.

  12. The role of mass spectrometry in atomic weight determinations.

    PubMed

    De Laeter, John R

    2009-01-01

    The 1914 Nobel Prize for Chemistry was awarded to Theodore Richards, whose work provided an insight into the history of the birth and evolution of matter as embedded in the atomic weights. However, the secret to unlocking the hieroglyphics contained in the atomic weights is revealed by a study of the relative abundances of the isotopes. A consistent set of internationally accepted atomic weights has been a goal of the scientific community for over a century. Atomic weights were originally determined by chemical stoichiometry--the so-called "Harvard Method," but this methodology has now been superseded by the "physical method," in which the isotopic composition and atomic masses of the isotopes comprising an element are used to calculate the atomic weight with far greater accuracy than before. The role of mass spectrometry in atomic weight determinations was initiated by the discovery of isotopes by Thomson, and established by the pioneering work of Aston, Dempster, and Nier using sophisticated mass spectrographs. The advent of the sector field mass spectrometer in 1947, revolutionized the application of mass spectrometry for both solids and gases to other fields of science including atomic weights. Subsequently, technological advances in mass spectrometry have enabled atomic masses to be determined with an accuracy better than one part in 10(7), whilst the absolute isotopic composition of many elements has been determined to produce accurate values of their atomic weights. Conversely, those same technological developments have revealed significant variations in the isotope abundances of many elements caused by a variety of physiochemical mechanisms in natural materials. Although these variations were initially seen as an impediment to the accuracy with which atomic weights could be determined, it was quickly realized that nature had provided a new tool to investigate physiochemical and biogeochemical mechanisms in nature, which could be exploited by precise and

  13. Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry.

    PubMed

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2015-03-03

    An ultra-high performance liquid chromatography based method, coupled to high resolution mass spectrometry (UHPLC-HRMS), was developed to permit the detection and quantification of various nitrofuran and chloramphenicol residues in a number of animal based food products. This method is based on the hydrolysis of covalently bound metabolites and derivatization with 2-nitrobenzaldehyde. Clean-up is achieved by a liquid/liquid and a reversed phase/solid phase extraction. Not only are the four conventional nitrofurans (nitrofurantoin, furazolidone, nitrofurazone and furaltadone) detected, but also nifursol, nitrovin and nifuroxazide. Furthermore, an underivatizable nitrofuran (nifurpirinol) and another banned drug (chloramphenicol) can be quantified as well. The compounds are detected in the form of their precursor ions, [M+H](+) and [M-H](-), respectively. The mass resolving power of 70,000 FWHM, and the applied mass window ensure sufficient selectivity and sensitivity. Confirmation is obtained by monitoring the HRMS resolved product ions which were derived from the unit-mass resolved precursor ions. The multiplexing capability of the utilized Orbitrap instrument provides not only highly selective, but also sensitive confirmatory signals. This method has been validated according to the CD 2002/657/EC for the following matrices: muscle, liver, kidney, fish, honey, eggs and milk.

  14. Mass Spectrometry Imaging of Complex Microbial Communities

    PubMed Central

    2016-01-01

    Conspectus In the two decades since mass spectrometry imaging (MSI) was first applied to visualize the distribution of peptides across biological tissues and cells, the technique has become increasingly effective and reliable. MSI excels at providing complementary information to existing methods for molecular analysis—such as genomics, transcriptomics, and metabolomics—and stands apart from other chemical imaging modalities through its capability to generate information that is simultaneously multiplexed and chemically specific. Today a diverse family of MSI approaches are applied throughout the scientific community to study the distribution of proteins, peptides, and small-molecule metabolites across many biological models. The inherent strengths of MSI make the technique valuable for studying microbial systems. Many microbes reside in surface-attached multicellular and multispecies communities, such as biofilms and motile colonies, where they work together to harness surrounding nutrients, fend off hostile organisms, and shield one another from adverse environmental conditions. These processes, as well as many others essential for microbial survival, are mediated through the production and utilization of a diverse assortment of chemicals. Although bacterial cells are generally only a few microns in diameter, the ecologies they influence can encompass entire ecosystems, and the chemical changes that they bring about can occur over time scales ranging from milliseconds to decades. Because of their incredible complexity, our understanding of and influence over microbial systems requires detailed scientific evaluations that yield both chemical and spatial information. MSI is well-positioned to fulfill these requirements. With small adaptations to existing methods, the technique can be applied to study a wide variety of chemical interactions, including those that occur inside single-species microbial communities, between cohabitating microbes, and between microbes

  15. Calculating Measurement Uncertainties for Mass Spectrometry Data

    NASA Astrophysics Data System (ADS)

    Essex, R. M.; Goldberg, S. A.

    2006-12-01

    A complete and transparent characterization of measurement uncertainty is fundamentally important to the interpretation of analytical results. We have observed that the calculation and reporting of uncertainty estimates for isotopic measurement from a variety of analytical facilities are inconsistent, making it difficult to compare and evaluate data. Therefore, we recommend an approach to uncertainty estimation that has been adopted by both US national metrology facilities and is becoming widely accepted within the analytical community. This approach is outlined in the ISO "Guide to the Expression of Uncertainty in Measurement" (GUM). The GUM approach to uncertainty estimation includes four major steps: 1) Specify the measurand; 2) Identify uncertainty sources; 3) Quantify components by determining the standard uncertainty (u) for each component; and 4) Calculate combined standard uncertainty (u_c) by using established propagation laws to combine the various components. To obtain a desired confidence level, the combined standard uncertainty is multiplied by a coverage factor (k) to yield an expanded uncertainty (U). To be consistent with the GUM principles, it is also necessary create an uncertainty budget, which is a listing of all the components comprising the uncertainty and their relative contribution to the combined standard uncertainty. In mass spectrometry, Step 1 is normally the determination of an isotopic ratio for a particular element. Step 2 requires the identification of the many potential sources of measurement variability and bias including: gain, baseline, cup efficiency, Schottky noise, counting statistics, CRM uncertainties, yield calibrations, linearity calibrations, run conditions, and filament geometry. Then an equation expressing the relationship of all of the components to the measurement value must be written. To complete Step 3, these potential sources of uncertainty must be characterized (Type A or Type B) and quantified. This information

  16. The allure of mass spectrometry: From an earlyday chemist's perspective

    PubMed Central

    2016-01-01

    1 This reminiscing review article is an account of the author's fascination and involvements with mass spectrometry from the perspective of an organic chemist with an interest in natural product chemistry. It covers a period from 1961 through the mid 1990s as mass spectrometry evolved form a novelty technique to become a most widely used analytical technique. Following a brief synopsis of my pathway to mass spectrometry, my research efforts in this field are presented with a focus mainly on evolving principles and technologies which I had personal involvements with. To provide historical perspectives, discussions of these developments are accompanied by brief outlines of the relevant state‐of‐the‐art, shedding light on the technical and conceptual challenges encountered during those early days in mass spectrometry. Examples are presented of my involvements with basic and applied research in mass spectrometry during graduate studies at Stanford University and close to three decade tenure in pharmaceutical research at Syntex Research. My basic research interests focused mainly on principles of electron ionization induced fragmentation mechanisms, with an emphasis on steroids and other model compounds. Extensive deuterium labeling evidence was used to determine the fragmentation mechanisms of the diagnostically significant ions in the spectra of numerous model compounds, uncovering examples of wide‐ranging hydrogen transfers, skeletal rearrangements, methyl and phenyl migrations, stereoselective fragmentations and low and high energy fragmentation processes. Depiction of the industrial research phase of my career includes comments on the pivotal role mass spectrometry played on advancing modern pharmaceutical research. Examples are presented of involvements with instrumental developments and a few select cases of applied research, including studies of bile mechanisms in vertebrates, identification of bisphenol‐A leaching from sterilized polycarbonate

  17. Mass Spectrometry of Atmospheric Pressure Surface Wave Discharges

    NASA Astrophysics Data System (ADS)

    Ridenti, M. A.; Souza-Corrêa, J. A.; Amorim, J.

    2016-05-01

    By applying mass spectrometry techniques, we carried out measurements of ionic mass spectrum and their energy distribution in order to investigate an atmospheric argon discharge by using a surfatron surface-wave device. The mass and energy distribution measurements were performed with fixed flow rate (2.5 SLM) of pure argon gas (99.999%) and different Ar-O2 gas mixture compositions (99-1, 98-2 and 97-3). The mass spectra and energy distributions were recorded for Ar+, O+, O+ 2, N+ and N2 +. The axial distribution profiles of ionic mass and their energy were obtained for different experimental conditions as a function of the plasma length. The results showed that the peak of the positive ion energy distributions shifted to higher energies and also that the distribution width increased as the distance between the sampling orifice and the launcher gap was increased. It was also found that under certain experimental conditions the ion flux of atomic species were higher than the ion flux of their diatomic counterpart. The motivation of this study was to obtain a better understanding of a surface wave discharge in atmospheric pressure that may play a key role on new second generation biofuel technologies.

  18. Unexpected Analyte Oxidation during Desorption Electrospray Ionization - Mass Spectrometry

    SciTech Connect

    Pasilis, Sofie P; Kertesz, Vilmos; Van Berkel, Gary J

    2008-01-01

    During the analysis of surface spotted analytes using desorption electrospray ionization mass spectrometry (DESI-MS), abundant ions are sometimes observed that appear to be the result of oxygen addition reactions. In this investigation, the effect of sample aging, the ambient lab environment, spray voltage, analyte surface concentration, and surface type on this oxidative modification of spotted analytes, exemplified by tamoxifen and reserpine, during analysis by desorption electrospray ionization mass spectrometry was studied. Simple exposure of the samples to air and to ambient lighting increased the extent of oxidation. Increased spray voltage lead also to increased analyte oxidation, possibly as a result of oxidative species formed electrochemically at the emitter electrode or in the gas - phase by discharge processes. These oxidative species are carried by the spray and impinge on and react with the sampled analyte during desorption/ionization. The relative abundance of oxidized species was more significant for analysis of deposited analyte having a relatively low surface concentration. Increasing spray solvent flow rate and addition of hydroquinone as a redox buffer to the spray solvent were found to decrease, but not entirely eliminate, analyte oxidation during analysis. The major parameters that both minimize and maximize analyte oxidation were identified and DESI-MS operational recommendations to avoid these unwanted reactions are suggested.

  19. Mass spectrometry-based proteomics: existing capabilities and future directions

    SciTech Connect

    Angel, Thomas E.; Aryal, Uma K.; Hengel, Shawna M.; Baker, Erin Shammel; Kelly, Ryan T.; Robinson, Errol W.; Smith, Richard D.

    2012-05-21

    Mass spectrometry-based proteomics provides a means for identification, characterization, and quantification of biomolecules that are integral components of the processes essential for life. Characterization of proteins present in a biological system at the proteome and sub-proteomes (e.g., the phosphoproteome, proteoglycome, or degradome/peptidome) levels provides a foundation for understanding fundamental aspects as well as potentially a range of translational applications. Emerging technologies such as ion mobility separations coupled with mass spectrometry and microchip-based - proteome measurements combined with continued enhancement of MS instrumentation and separation techniques, such as reversed phase liquid chromatography and potentially capillary electrophoresis, show great promise for both broad undirected as well as targeted measurements and will be critical for e.g., the proteome-wide characterization of post translational modifications and identification, or the verification, and validation of potential biomarkers of disease. MS-based proteomics is also increasingly demonstrating great potential for contributing to our understanding of the dynamics, reactions, and roles proteins and peptides play advancing our understanding of biology on a system wide level for a wide range of applications, from investigations of microbial communities, bioremediation, and human health and disease states alike.

  20. Analysis of hazardous biological material by MALDI mass spectrometry

    SciTech Connect

    KL Wahl; KH Jarman; NB Valentine; MT Kingsley; CE Petersen; ST Cebula; AJ Saenz

    2000-03-21

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) has become a valuable tool for analyzing microorganisms. The speed with which data can be obtained from MALDI-MS makes this a potentially important tool for biological health hazard monitoring and forensic applications. The excitement in the mass spectrometry community in this potential field of application is evident by the expanding list of research laboratories pursuing development of MALDI-MS for bacterial identification. Numerous research groups have demonstrated the ability to obtain unique MALDI-MS spectra from intact bacterial cells and bacterial cell extracts. The ability to differentiate strains of the same species has been investigated. Reproducibility of MALDI-MS spectra from bacterial species under carefully controlled experimental conditions has also been demonstrated. Wang et al. have reported on interlaboratory reproducibility of the MALDI-MS analysis of several bacterial species. However, there are still issues that need to be addressed, including the careful control of experimental parameters for reproducible spectra and selection of optimal experimental parameters such as solvent and matrix.

  1. Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams

    SciTech Connect

    Debord, J. Daniel; Smith, Donald F.; Anderton, Christopher R.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana; Gomer, Richard H.; Fernandez-Lima, Francisco A.

    2014-06-09

    High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.

  2. NCBI Peptidome: a new repository for mass spectrometry proteomics data.

    PubMed

    Ji, Li; Barrett, Tanya; Ayanbule, Oluwabukunmi; Troup, Dennis B; Rudnev, Dmitry; Muertter, Rolf N; Tomashevsky, Maxim; Soboleva, Alexandra; Slotta, Douglas J

    2010-01-01

    Peptidome is a public repository that archives and freely distributes tandem mass spectrometry peptide and protein identification data generated by the scientific community. Data from all stages of a mass spectrometry experiment are captured, including original mass spectra files, experimental metadata and conclusion-level results. The submission process is facilitated through acceptance of data in commonly used open formats, and all submissions undergo syntactic validation and curation in an effort to uphold data integrity and quality. Peptidome is not restricted to specific organisms, instruments or experiment types; data from any tandem mass spectrometry experiment from any species are accepted. In addition to data storage, web-based interfaces are available to help users query, browse and explore individual peptides, proteins or entire Samples and Studies. Results are integrated and linked with other NCBI resources to ensure dissemination of the information beyond the mass spectroscopy proteomics community. Peptidome is freely accessible at http://www.ncbi.nlm.nih.gov/peptidome.

  3. Differential mobility spectrometry/mass spectrometry history, theory, design optimization, simulations, and applications.

    PubMed

    Schneider, Bradley B; Nazarov, Erkinjon G; Londry, Frank; Vouros, Paul; Covey, Thomas R

    2016-10-01

    This review of differential mobility spectrometry focuses primarily on mass spectrometry coupling, starting with the history of the development of this technique in the Soviet Union. Fundamental principles of the separation process are covered, in addition to efforts related to design optimization and advancements in computer simulations. The flexibility of differential mobility spectrometry design features is explored in detail, particularly with regards to separation capability, speed, and ion transmission. 2015 Wiley Periodicals, Inc. Mass Spec Rev 35:687-737, 2016. © 2015 Wiley Periodicals, Inc.

  4. Analysis of Milk Oligosaccharides by Mass Spectrometry.

    PubMed

    Wu, Lauren D; Ruhaak, L Renee; Lebrilla, Carlito B

    2017-01-01

    Human milk oligosaccharides (HMOs) are a highly abundant constituent in human milk, and its protective and prebiotic properties have attracted considerable attention. HMOs have been shown to directly and indirectly benefit the overall health of the infant due to a number of functions including serving as a beneficial food for gut bacteria, block to pathogens, and aiding in brain development. Researchers are currently exploring whether these structures may act as possible disease and nutrition biomarkers. Because of this, rapid-throughput methods are desired to investigate biological activity in large patient sets. We have optimized a rapid-throughput protocol to analyze human milk oligosaccharides using micro-volumes of human breast milk for nutritional biomarkers. This method may additionally be applied to other biological fluid substrates such as plasma, urine, and feces. The protocol involves lipid separation via centrifugation, protein precipitation using ethanol, alditol reduction with sodium borohydride, and a final solid-phase extraction purification step using graphitized carbon cartridges. Samples are analyzed using HPLC-Chip/TOF-MS and data filtered on Agilent MassHunter using an in-house library. Individual structural identification is matched against a previously developed HMO library using accurate mass and retention time. Using this method will allow in-depth characterization and profiling of HMOs in large patient sets, and will ease the process of discovering significant nutritional biomarkers in human milk.

  5. Noncovalent Shiga-like toxin assemblies: characterization by means of mass spectrometry and tandem mass spectrometry.

    PubMed

    Williams, Jonathan P; Green, Brian N; Smith, Daniel C; Jennings, Keith R; Moore, Katherine A H; Slade, Susan E; Roberts, Lynne M; Scrivens, James H

    2005-06-14

    Shiga-like toxin 1 (SLTx), produced by enterohemorrhagic strains of Escherichia coli (EHEC), belongs to a family of structurally and functionally related AB(5) protein toxins that are associated with human disease. EHEC infection often gives rise to hemolytic colitis, while toxin-induced kidney damage is one of the major causes of hemolytic uremic syndrome (HUS) and acute renal failure in children. As such, an understanding and analysis of the noncovalent interactions that maintain the quaternary structure of this toxin are fundamentally important since such interactions have significant biochemical and medical implications. This paper reports on the analysis of the noncovalent homopentameric complex of Shiga-like toxin B chain (SLTx-B(5)) using electrospray ionization (ESI) triple-quadrupole (QqQ) mass spectrometry (MS) and tandem mass spectrometry (MS/MS) and the analysis of the noncovalent hexameric holotoxin (SLTx-AB(5)) using ESI time-of-flight (TOF) MS. The triple-quadrupole analysis revealed highly charged monomer ions dissociate from the multiprotein complex to form dimer, trimer, and tetramer product ions, which were also seen to further dissociate. The ESI-TOFMS analysis of SLTx-AB(5) revealed the complex remained intact and was observed in the gas phase over a range of pHs. Theses findings demonstrate that the gas-phase structure observed for both the holotoxin and the isoloated B chains correlates well with the structures reported to exist in the solution phase for these proteins. Such analysis provides a rapid screening technique for assessing the noncovalent structure of this family of proteins and other structurally related toxins.

  6. Evaluating plant immunity using mass spectrometry-based metabolomics workflows

    PubMed Central

    Heuberger, Adam L.; Robison, Faith M.; Lyons, Sarah Marie A.; Broeckling, Corey D.; Prenni, Jessica E.

    2014-01-01

    Metabolic processes in plants are key components of physiological and biochemical disease resistance. Metabolomics, the analysis of a broad range of small molecule compounds in a biological system, has been used to provide a systems-wide overview of plant metabolism associated with defense responses. Plant immunity has been examined using multiple metabolomics workflows that vary in methods of detection, annotation, and interpretation, and the choice of workflow can significantly impact the conclusions inferred from a metabolomics investigation. The broad range of metabolites involved in plant defense often requires multiple chemical detection platforms and implementation of a non-targeted approach. A review of the current literature reveals a wide range of workflows that are currently used in plant metabolomics, and new methods for analyzing and reporting mass spectrometry (MS) data can improve the ability to translate investigative findings among different plant-pathogen systems. PMID:25009545