WorldWideScience

Sample records for activity-based mass spectrometric

  1. Mass spectrometric immunoassay

    Science.gov (United States)

    Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

    2007-12-04

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  2. Mass Spectrometric Studies of Oxides

    Science.gov (United States)

    Jacobson, Nathan S.

    2012-01-01

    Current studies at NASA Glenn on oxide thermodynamics are discussed. Previous studies on the vaporization of B2O3 in reducing atmospheres led to inconsistent studies when B was used as a reductant. It is shown that liquid B2O3 does not wet B and a clear phase separation was noted in the Knudsen cell. This problem was solved by using FeB and Fe2B to supply a different and constant activity of B. The thermodynamic data thus derived are compared to quantum chemical composite calculations. A major problem in high temperature mass spectrometry is the determination of accurate ionization cross sections, particularly for molecules. The method of Deutsch and Mark shows promise and some sample calculations are discussed. Finally current studies on the thermodynamics of rare earth silicates are discussed. Here the problems are obtaining a measurable signal from SiO2 vaporization and non-equilibrium vaporization. The use of a Ta reducing agent provides a stronger signal, which is related to silica activity. The Whitman-Motzfeld relation adapted to KEMS measurements is applied to obtain equilibrium pressures.

  3. Recent advances in mass spectrometric applications in hydrology

    International Nuclear Information System (INIS)

    The recent advances in mass spectrometric applications in hydrology include 18O of nitrates and sulphates, 37Cl of chlorides for studying origin of groundwater pollution, 3He/4He for geothermal fluids and analysis, 14C, 36Cl and 129I for dating groundwater by Accelerator Mass Spectrometry (AMS)

  4. Characterization of nuclear fuels by ICP mass-spectrometric techniques

    International Nuclear Information System (INIS)

    Isotopic analyses of radioactive materials such as irradiated nuclear fuel are of major importance for the optimization of the nuclear fuel cycle and for safeguard aspects. Among the mass-spectrometric techniques available, inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry are the most frequently applied methods for nuclear applications. Because of the low detection limits, the ability to analyze the isotopic composition of the elements and the applicability of the techniques for measuring stable as well as radioactive nuclides with similar sensitivity, both mass-spectrometric techniques are an excellent amendment to classical radioactivity counting methods. The paper describes selected applications of multicollector ICP-MS in combination with chromatographic separation techniques and laser ablation for the isotopic analysis of irradiated nuclear fuels. The advantages and limitations of the selected analytical technique for the characterization of such a heterogeneous sample matrix are discussed. (orig.)

  5. Challenges and recent advances in mass spectrometric imaging of neurotransmitters

    OpenAIRE

    Gemperline, Erin; Chen, Bingming; Li, Lingjun

    2014-01-01

    Mass spectrometric imaging (MSI) is a powerful tool that grants the ability to investigate a broad mass range of molecules, from small molecules to large proteins, by creating detailed distribution maps of selected compounds. To date, MSI has demonstrated its versatility in the study of neurotransmitters and neuropeptides of different classes toward investigation of neurobiological functions and diseases. These studies have provided significant insight in neurobiology over the years and curre...

  6. Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides

    Directory of Open Access Journals (Sweden)

    Lajos Kovács

    2012-07-01

    Full Text Available Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+ etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds.

  7. Mass spectrometric detection, identification, and fragmentation of arseno-phytochelatins.

    Science.gov (United States)

    Schmied-Tobies, Maria I H; Arroyo-Abad, Uriel; Mattusch, Jürgen; Reemtsma, Thorsten

    2014-11-01

    Phytochelatins (PC) are cystein-rich oligopeptides in plants for coordination with toxic metals and metalloids via their thiol groups. The composition, structure, and mass spectrometric fragmentation of arseno-PC (As-PC) with PC of different degree of oligomerization (PC2-PC5) in solution were studied using liquid chromatography coupled in parallel to inductively coupled plasma mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. As-PC were detected from As(PC2) to As(PC5) with an increasing number of isomers that differ in the position of thiol groups bound to As. Thermodynamic modeling supported the identification process in case of these isomers. Mass spectrometric fragmentation of the As-PC does not follow the established pattern of peptides but is governed by the formation of series of As-containing annular cations, which coordinate to As via S, N, or O. Structure proposals for 30 As-PC fragment ions in the range m/z 147.92 to m/z 1290.18 are elaborated. Many of these fragment ions are characteristic to several As-PC and may be suited for a screening for As-PC in plant extracts. The mass spectrometric data offer the perspective for a future more sensitive determination of As-PC by means of liquid chromatography tandem mass spectrometry with multiple reaction monitoring. PMID:25395130

  8. Mass spectrometric detection, identification, and fragmentation of arseno-phytochelatins.

    Science.gov (United States)

    Schmied-Tobies, Maria I H; Arroyo-Abad, Uriel; Mattusch, Jürgen; Reemtsma, Thorsten

    2014-11-01

    Phytochelatins (PC) are cystein-rich oligopeptides in plants for coordination with toxic metals and metalloids via their thiol groups. The composition, structure, and mass spectrometric fragmentation of arseno-PC (As-PC) with PC of different degree of oligomerization (PC2-PC5) in solution were studied using liquid chromatography coupled in parallel to inductively coupled plasma mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. As-PC were detected from As(PC2) to As(PC5) with an increasing number of isomers that differ in the position of thiol groups bound to As. Thermodynamic modeling supported the identification process in case of these isomers. Mass spectrometric fragmentation of the As-PC does not follow the established pattern of peptides but is governed by the formation of series of As-containing annular cations, which coordinate to As via S, N, or O. Structure proposals for 30 As-PC fragment ions in the range m/z 147.92 to m/z 1290.18 are elaborated. Many of these fragment ions are characteristic to several As-PC and may be suited for a screening for As-PC in plant extracts. The mass spectrometric data offer the perspective for a future more sensitive determination of As-PC by means of liquid chromatography tandem mass spectrometry with multiple reaction monitoring.

  9. Mass spectrometric analysis of protein interactions

    DEFF Research Database (Denmark)

    Borch, Jonas; Jørgensen, Thomas J. D.; Roepstorff, Peter

    2005-01-01

    Mass spectrometry is a powerful tool for identification of interaction partners and structural characterization of protein interactions because of its high sensitivity, mass accuracy and tolerance towards sample heterogeneity. Several tools that allow studies of protein interaction are now...... available and recent developments that increase the confidence of studies of protein interaction by mass spectrometry include quantification of affinity-purified proteins by stable isotope labeling and reagents for surface topology studies that can be identified by mass-contributing reporters (e.g. isotope...... labels, cleavable cross-linkers or fragment ions. The use of mass spectrometers to study protein interactions using deuterium exchange and for analysis of intact protein complexes recently has progressed considerably....

  10. Mass Spectrometric Analysis of Water-soluble Gold Nanoclusters

    International Nuclear Information System (INIS)

    Batches of water-soluble gold nanoclusters of nominal 2.0 or 3.5-nm diameter were prepared to evaluate particle size determinations by a number of techniques such as transmission electron microscopy or atomic force microscopy and to validate estimates derived by mass spectrometric analysis using matrix-assisted laser desorption ionization (MALDI). Good agreement was found and MALDI lends itself to analyses even in the presence of aggregates

  11. Hydrogen preparation system for mass spectrometric analysis

    International Nuclear Information System (INIS)

    A gas source mass spectrometer has been recently set up at PINSTECH to carry out hydrological mapping of Pakistan by measuring isotopic ratio variations in H2, O2 and CO2 in waters of different origin. For D/H ratio analyses using this mass spectrometer water sample of size 20-25 microliter is to be converted to hydrogen gas. The preparation system developed for this purpose is described. (author)

  12. Visualization of High Resolution Spatial Mass Spectrometric Data during Acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Mathew; Heath, Brandi S.; Laskin, Julia; Li, Dongsheng; Liu, Ellen C.; Hui, Katrina L.; Kuprat, Andrew P.; Kleese van Dam, Kerstin; Carson, James P.

    2012-08-28

    Mass Spectrometric Imaging (IMS) allows the generation of 2D ion density maps that help visualize molecules present in sections of tissues and cells. The combination of spatial and mass resolution results in large and complex data sets that require powerful and efficient analysis and interpretation. In this paper, a graphical user interface (GUI) that can visualize the large data during data acquisition itself is presented. The program also has the ability to perform processing and analysis of the dataset. The various functions of the GUI including visualization of mass spectra, generation of 2D maps for selected species, manipulation of the heat maps, and peak identification are also presented.

  13. Mass spectrometric imaging of ginsenosides localization in Panax ginseng root

    OpenAIRE

    Taira, Shu; Ikeda, Ryuzo; Yokota, Naohiko; OSAKA, Issey; Sakamoto, Manabu; Kato, Mitsuro; Sahashi, Yuko

    2010-01-01

    We succeeded in performing mass spectrometric imaging (MSI) of the localization of ginsenosides (Rb_1, Rb_2 or R_c, and Rf) in cross-sections of the Panax ginseng root at a resolution of 100 μm using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Tandem mass spectrometry (MS/MS) of alkali metal-adducted ginsenoside ions revealed structural information of the corresponding saccharides and agricones. MALDI-MSI confirmed that localization of ginsenosides in the cortex ...

  14. Mass Spectrometric Analysis of Histone Proteoforms

    Science.gov (United States)

    Yuan, Zuo-Fei; Arnaudo, Anna M.; Garcia, Benjamin A.

    2014-06-01

    Histones play important roles in chromatin, in the forms of various posttranslational modifications (PTMs) and sequence variants, which are called histone proteoforms. Investigating modifications and variants is an ongoing challenge. Previous methods are based on antibodies, and because they usually detect only one modification at a time, they are not suitable for studying the various combinations of modifications on histones. Fortunately, mass spectrometry (MS) has emerged as a high-throughput technology for histone analysis and does not require prior knowledge about any modifications. From the data generated by mass spectrometers, both identification and quantification of modifications, as well as variants, can be obtained easily. On the basis of this information, the functions of histones in various cellular contexts can be revealed. Therefore, MS continues to play an important role in the study of histone proteoforms. In this review, we discuss the analysis strategies of MS, their applications on histones, and some key remaining challenges.

  15. Mass spectrometric analysis of monolayer protected nanoparticles

    Science.gov (United States)

    Zhu, Zhengjiang

    Monolayer protected nanoparticles (NPs) include an inorganic core and a monolayer of organic ligands. The wide variety of core materials and the tunable surface monolayers make NPs promising materials for numerous applications. Concerns related to unforeseen human health and environmental impacts of NPs have also been raised. In this thesis, new analytical methods based on mass spectrometry are developed to understand the fate, transport, and biodistributions of NPs in the complex biological systems. A laser desorption/ionization mass spectrometry (LDI-MS) method has been developed to characterize the monolayers on NP surface. LDI-MS allows multiple NPs taken up by cells to be measured and quantified in a multiplexed fashion. The correlations between surface properties of NPs and cellular uptake have also been explored. LDI-MS is further coupled with inductively coupled plasma mass spectrometry (ICP-MS) to quantitatively measure monolayer stability of gold NPs (AuNPs) and quantum dots (QDs), respectively, in live cells. This label-free approach allows correlating monolayer structure and particle size with NP stability in various cellular environments. Finally, uptake, distribution, accumulation, and excretion of NPs in higher order organisms, such as fish and plants, have been investigated to understand the environmental impact of nanomaterials. The results indicate that surface chemistry is a primary determinant. NPs with hydrophilic surfaces are substantially less toxic and present a lower degree of bioaccumulation, making these nanomaterials attractive for sustainable nanotechnology.

  16. The hydrolysis of aluminium, a mass spectrometric study

    OpenAIRE

    Sarpola, A.

    2007-01-01

    Abstract This thesis is focused on the hydrolysis of aluminium, the polymerisation of the hydrolysis products, and how these can be monitored by mass spectrometric methods. The main aim of this research is to figure out how the aqueous speciation of aluminium changes as a function of pH (3.2–10), concentration (1–100 mM), reaction time (1s–14d), and counter anion (Cl-, SO42-, HCOO-). The method used was electrospray mass spectrometry. The results showed more variable speciation than those ...

  17. Mass spectrometric detection of radiocarbon for dating applications

    Energy Technology Data Exchange (ETDEWEB)

    Synal, H.-A., E-mail: synal@phys.ethz.ch [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland); Schulze-Koenig, T.; Seiler, M.; Suter, M.; Wacker, L. [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland)

    2013-01-15

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV {sup 14}C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  18. Mass spectrometric detection of radiocarbon for dating applications

    Science.gov (United States)

    Synal, H.-A.; Schulze-König, T.; Seiler, M.; Suter, M.; Wacker, L.

    2013-01-01

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV 14C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  19. Mass spectrometric determination of early and advanced glycation in biology.

    Science.gov (United States)

    Rabbani, Naila; Ashour, Amal; Thornalley, Paul J

    2016-08-01

    Protein glycation in biological systems occurs predominantly on lysine, arginine and N-terminal residues of proteins. Major quantitative glycation adducts are found at mean extents of modification of 1-5 mol percent of proteins. These are glucose-derived fructosamine on lysine and N-terminal residues of proteins, methylglyoxal-derived hydroimidazolone on arginine residues and N(ε)-carboxymethyl-lysine residues mainly formed by the oxidative degradation of fructosamine. Total glycation adducts of different types are quantified by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Metabolism of glycated proteins is followed by LC-MS/MS of glycation free adducts as minor components of the amino acid metabolome. Glycated proteins and sites of modification within them - amino acid residues modified by the glycating agent moiety - are identified and quantified by label-free and stable isotope labelling with amino acids in cell culture (SILAC) high resolution mass spectrometry. Sites of glycation by glucose and methylglyoxal in selected proteins are listed. Key issues in applying proteomics techniques to analysis of glycated proteins are: (i) avoiding compromise of analysis by formation, loss and relocation of glycation adducts in pre-analytic processing; (ii) specificity of immunoaffinity enrichment procedures, (iii) maximizing protein sequence coverage in mass spectrometric analysis for detection of glycation sites, and (iv) development of bioinformatics tools for prediction of protein glycation sites. Protein glycation studies have important applications in biology, ageing and translational medicine - particularly on studies of obesity, diabetes, cardiovascular disease, renal failure, neurological disorders and cancer. Mass spectrometric analysis of glycated proteins has yet to find widespread use clinically. Future use in health screening, disease diagnosis and therapeutic monitoring, and

  20. Advances in Mass Spectrometric Tools for Probing Neuropeptides

    Science.gov (United States)

    Buchberger, Amanda; Yu, Qing; Li, Lingjun

    2015-07-01

    Neuropeptides are important mediators in the functionality of the brain and other neurological organs. Because neuropeptides exist in a wide range of concentrations, appropriate characterization methods are needed to provide dynamic, chemical, and spatial information. Mass spectrometry and compatible tools have been a popular choice in analyzing neuropeptides. There have been several advances and challenges, both of which are the focus of this review. Discussions range from sample collection to bioinformatic tools, although avenues such as quantitation and imaging are included. Further development of the presented methods for neuropeptidomic mass spectrometric analysis is inevitable, which will lead to a further understanding of the complex interplay of neuropeptides and other signaling molecules in the nervous system.

  1. Mass spectrometric profiling of flavonoid glycoconjugates possessing isomeric aglycones.

    Science.gov (United States)

    Abrankó, László; Szilvássy, Blanka

    2015-01-01

    In fields such as food and nutrition science or plant physiology, interest in untargeted profiling of flavonoids continues to expand. The group of flavonoids encompasses several thousands of chemically distinguishable compounds, among which are a number of isobaric compounds with the same elemental composition. Thus, the mass spectrometric identification of these compounds is challenging, especially when reference standards are not available to support their identification. Many different types of isomers of flavonoid glycoconjugates are known, i.e. compounds that differ in their glycosylation position, glycan sequence or type of interglycosidic linkage. This work focuses on the mass spectrometric identification of flavonoid glycoconjugate isomers possessing the same glycan mass and differing only in their aglycone core. A non-targeted HPLC-ESI-MS/MS profiling method using a triple quadrupole MS is presented herein, which utilizes in-source fragmentation and a pseudo-MS(3) approach for the selective analysis of flavonoid glycoconjugates with isomeric/isobaric aglycones. A selective MRM-based identification of the in-source formed isobaric aglycone fragments was established. Additionally, utilizing the precursor scanning capability of the employed triple quadrupole instrument, the developed method enabled the determination of the molecular weight of the studied intact flavonoid glycoconjugate. The versatility of the method was proven with various types of flavonoid aglycones, i.e. anthocyanins, flavonols, flavones, flavanones and isoflavones, along with their representative glycoconjugates. The developed method was also successfully applied to a commercially available sour cherry sample, in which 16 different glycoconjugates of pelargonidin, genistein, cyanidin, kaempferol and quercetin could be tentatively identified, including a number of compounds containing isomeric/isobaric aglycones. PMID:25601677

  2. Extraction, chromatographic and mass spectrometric methods for lipid analysis.

    Science.gov (United States)

    Pati, Sumitra; Nie, Ben; Arnold, Robert D; Cummings, Brian S

    2016-05-01

    Lipids make up a diverse subset of biomolecules that are responsible for mediating a variety of structural and functional properties as well as modulating cellular functions such as trafficking, regulation of membrane proteins and subcellular compartmentalization. In particular, phospholipids are the main constituents of biological membranes and play major roles in cellular processes like transmembrane signaling and structural dynamics. The chemical and structural variety of lipids makes analysis using a single experimental approach quite challenging. Research in the field relies on the use of multiple techniques to detect and quantify components of cellular lipidomes as well as determine structural features and cellular organization. Understanding these features can allow researchers to elucidate the biochemical mechanisms by which lipid-lipid and/or lipid-protein interactions take place within the conditions of study. Herein, we provide an overview of essential methods for the examination of lipids, including extraction methods, chromatographic techniques and approaches for mass spectrometric analysis.

  3. Surface acoustic wave nebulization facilitating lipid mass spectrometric analysis.

    Science.gov (United States)

    Yoon, Sung Hwan; Huang, Yue; Edgar, J Scott; Ting, Ying S; Heron, Scott R; Kao, Yuchieh; Li, Yanyan; Masselon, Christophe D; Ernst, Robert K; Goodlett, David R

    2012-08-01

    Surface acoustic wave nebulization (SAWN) is a novel method to transfer nonvolatile analytes directly from the aqueous phase to the gas phase for mass spectrometric analysis. The lower ion energetics of SAWN and its planar nature make it appealing for analytically challenging lipid samples. This challenge is a result of their amphipathic nature, labile nature, and tendency to form aggregates, which readily precipitate clogging capillaries used for electrospray ionization (ESI). Here, we report the use of SAWN to characterize the complex glycolipid, lipid A, which serves as the membrane anchor component of lipopolysaccharide (LPS) and has a pronounced tendency to clog nano-ESI capillaries. We also show that unlike ESI SAWN is capable of ionizing labile phospholipids without fragmentation. Lastly, we compare the ease of use of SAWN to the more conventional infusion-based ESI methods and demonstrate the ability to generate higher order tandem mass spectral data of lipid A for automated structure assignment using our previously reported hierarchical tandem mass spectrometry (HiTMS) algorithm. The ease of generating SAWN-MS(n) data combined with HiTMS interpretation offers the potential for high throughput lipid A structure analysis. PMID:22742654

  4. Functional proteomics with new mass spectrometric and bioinformatics tools

    International Nuclear Information System (INIS)

    A comprehensive range of mass spectrometric tools is required to investigate todays life science applications and a strong focus is on addressing the needs of functional proteomics. Application examples are given showing the streamlined process of protein identification from low femtomole amounts of digests. Sample preparation is achieved with a convertible robot for automated 2D gel picking, and MALDI target dispensing. MALDI-TOF or ESI-MS subsequent to enzymatic digestion. A choice of mass spectrometers including Q-q-TOF with multipass capability, MALDI-MS/MS with unsegmented PSD, Ion Trap and FT-MS are discussed for their respective strengths and applications. Bioinformatics software that allows both database work and novel peptide mass spectra interpretation is reviewed. The automated database searching uses either entire digest LC-MSn ESI Ion Trap data or MALDI MS and MS/MS spectra. It is shown how post translational modifications are interactively uncovered and de-novo sequencing of peptides is facilitated

  5. Method of double tracer addition for determining uranium in geological samples by mass spectrometric isotope dilution

    International Nuclear Information System (INIS)

    The present work shows the experimental details on the uranium determination in materials by mass spectrometric isotope dilution technique with double tracer (233U + 235U). The mass discrimination phenomenon effect is studied. The uranium concentration values obtained by mass spectrometric isotope dilution technique with double tracer are compared with other techniques. The influence of the sampling in the accurate determination of uranium in the rock sample is discussed. (author)

  6. Mass spectrometric study of the amipurimycin hexopyranosidic sugar moiety

    Science.gov (United States)

    Almoster Ferreira, M. A.; Borges, C.; Oliveira, M. C.; Pocsfalvi, G.; Rauter, A. P.; Fernandes, A. C.

    1997-11-01

    Amipurimycin is a natural nucleoside that displays a remarkable activity in vitro and in vivo against Pyricularia oryzae, which is responsible for the rice blast disease. Six important precursors for the synthesis of the Amipurimycin sugar moiety were prepared. In order to obtain structural information a mass spectrometric study of these compounds was performed using liquid secondary ion mass spectrometry (LSIMS) with high-energy collision-induced dissociation (CID) experiments on a four-sector instrument. Elimination of methanol is the preferential fragmentation path for five of the six protonated molecules, indicating that protonation plays an important role in the process, whilst for the other protonated molecule loss of water is the main fragmentation. Examination of the [M + Li]+ precursor ion spectra shows that loss of methanol does not occur in three of them, but in the other three gives rise to fairly abundant ions, indicating that in this case methanol elimination implies intramolecular hydrogen transfer, the resulting ion having a very stable structure.

  7. Status of mass spectrometric radiocarbon detection at ETHZ

    Science.gov (United States)

    Seiler, Martin; Maxeiner, Sascha; Wacker, Lukas; Synal, Hans-Arno

    2015-10-01

    A prototype of a mass spectrometric radiocarbon detection instrument without accelerator stage was built for the first time and set into operation at ETH Zurich. The system is designed as an experimental platform to optimize performance of 14C detection at low ion energies and to study the most relevant processes that may limit system performance. The optimized stripper unit incorporates differential pumping to maintain a low gas outflow and a revised tube design to better match the phase space volume of the ion beam at low energies. The system is fully operational and has demonstrated true radiocarbon dating capabilities. The overall beam transmission through the stripper tube is about 40% for the 1+ charge state. Radiocarbon analyses with an overall precision of 0.6% were obtained on a single sample under regular measurement conditions. By analyzing multiple targets of the same sample material an uncertainty level of 0.3% has been reached. The background level corresponds to a radiocarbon age of 40,000 years.

  8. Single hair cocaine consumption monitoring by mass spectrometric imaging.

    Science.gov (United States)

    Porta, Tiffany; Grivet, Chantal; Kraemer, Thomas; Varesio, Emmanuel; Hopfgartner, Gérard

    2011-06-01

    Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was used to image the distribution of cocaine and its metabolites in intact single hair samples from chronic users down to a concentration of 5 ng/mg. Acquisitions were performed in rastering mode, at a speed of 1 mm/s and in the selected reaction monitoring (SRM) mode on a MALDI triple quadrupole linear ion trap fitted with a high repetition rate laser (1 kHz). Compared to traditional methods based on LC-MS/MS or GC-MS(/MS) which require to segment the hair to obtain spatial resolution, MALDI-MSI, with a straightforward sample preparation beforehand, allowed obtaining a spatial resolution of 1 mm and thus the chronological information about cocaine consumption contained in a single intact hair over several months could be monitored. The analysis time of an intact single hair sample of 6 cm is approximately of 6 min. Cocaine and its metabolites benzoylecgonine, ethylcocaine, and norcocaine were investigated in nine sets of hair samples for forensic purposes. The analyses were accomplished by spraying α-cyano-4-hydroxycinnamic acid (CHCA), 4-chloro-α-cyano-cinnamic acid (Cl-CCA), or (E)-2-cyano-3-(naphthalen-2-yl)acrylic acid (NpCCA) as MALDI matrices. We also propose a rapid strategy for sensitive confirmatory analyses with both MS/MS and MS(3) experiments performed directly on intact hair samples. Since only part of the hair strand is analyzed, additional analyses are possible at any time on the remaining hair from the strand. PMID:21510611

  9. Modular mass spectrometric tool for analysis of composition and phosphorylation of protein complexes.

    Directory of Open Access Journals (Sweden)

    Justin D Blethrow

    Full Text Available The combination of high accuracy, sensitivity and speed of single and multiple-stage mass spectrometric analyses enables the collection of comprehensive sets of data containing detailed information about complex biological samples. To achieve these properties, we combined two high-performance matrix-assisted laser desorption ionization mass analyzers in one modular mass spectrometric tool, and applied this tool for dissecting the composition and post-translational modifications of protein complexes. As an example of this approach, we here present studies of the Saccharomyces cerevisiae anaphase-promoting complexes (APC and elucidation of phosphorylation sites on its components. In general, the modular concept we describe could be useful for assembling mass spectrometers operating with both matrix-assisted laser desorption ionization (MALDI and electrospray ionization (ESI ion sources into powerful mass spectrometric tools for the comprehensive analysis of complex biological samples.

  10. Hydrogen--deuterium exchange in water vapor: the mass spectrometric sensitivities and the equilibrium constant

    Energy Technology Data Exchange (ETDEWEB)

    Pyper, J.W.; Dupzyk, R.J.; Friesen, R.D.; Bernasek, S.L.; May, C.A.; Echeverria, A.W.; Tolman, L.F.

    1976-04-21

    The equilibrium constant, K/sub HDO/, for the reaction H/sub 2/O + D/sub 2/O = 2HDO can be expressed as an intensity ratio, I, measured mass spectrometrically, times a sensitivity ratio, S, measured in mass spectrometric calibration experiments. The latter is difficult to measure and previously was assumed to be unity. The 2.4 percent discrepancy between K's from theoretical calculations and direct mass spectrometric measurements might be explained by another value of S. An indirect measurement of S using a pulsed-molecular beam quadrupole mass filter that has a unique three-chamber, three-leak gas inlet system is reported. The results show the sensitivities are probably equal and therefore S = 1. Systematic errors were found in the procedure, however, which precluded an unambiguous test of the theory.

  11. Protein nitration in biological aging: proteomic and tandem mass spectrometric characterization of nitrated sites.

    Science.gov (United States)

    Kanski, Jaroslaw; Schöneich, Christian

    2005-01-01

    Proteomic techniques for the identification of 3-nitrotyrosine-containing proteins in various biological systems are described with emphasis on the direct mass spectrometric detection and sequencing of 3-nitrotyrosine-containing peptides. Strengths and weaknesses of various separation and mass spectrometric techniques are discussed. Some examples for the MS/MS analysis of nitrated peptides obtained from aging rat heart and skeletal muscle are provided, such as nitration of Tyr105 of the mitochondrial electron-transfer flavoprotein and Tyr14 of creatine kinase.

  12. Mass spectrometric analysis of integral membrane proteins: application to complete mapping of bacteriorhodopsins and rhodopsin.

    OpenAIRE

    Ball, L. E.; Oatis, J. E.; Dharmasiri, K.; Busman, M.; Wang, J.; Cowden, L. B.; Galijatovic, A.; N. Chen; Crouch, R K; Knapp, D R

    1998-01-01

    Integral membrane proteins have not been readily amenable to the general methods developed for mass spectrometric (or internal Edman degradation) analysis of soluble proteins. We present here a sample preparation method and high performance liquid chromatography (HPLC) separation system which permits online HPLC-electrospray ionization mass spectrometry (ESI-MS) and -tandem mass spectrometry (MS/MS) analysis of cyanogen bromide cleavage fragments of integral membrane proteins. This method has...

  13. Mass spectrometric analysis of isotope effects in bioconversion of benzene to cyclohexanone

    Science.gov (United States)

    Nam, In-Hyun; Murugesan, Kumarasamy; Kim, Young-Mo; Yang, In-Hee; Chang, Yoon-Seok

    2006-06-01

    Pseudomonas veronii strain PH-03 has been shown to convert benzene to cyclohexanone through phenol. Mass spectrometry results revealed that unusual isotopic effects have been occurred in the transformation product, cyclohexanone. The isotopic composition was strongly depends on the compound specific hydrogen or oxygen source. The exchange of labile deuterium atoms has been investigated through electrospray ionization liquid chromatography mass spectrometry. The mass spectrometric analysis of biotransformation products enabled the proposal of a corresponding bioconversion pathway.

  14. Mass Spectrometric Method for Analyzing Metabolites in Yeast with Single Cell Sensitivity

    NARCIS (Netherlands)

    Amantonico, Andrea; Oh, Joo Yeon; Sobek, Jens; Heinemann, Matthias; Zenobi, Renato

    2008-01-01

    Getting a look-in: An optimized MALDI-MS procedure has been developed to detect endogenous primary metabolites directly in the cell extract. A detection limit corresponding to metabolites from less than a single cell has been attained, opening the door to single-cell metabolomics by mass spectrometr

  15. Thermal ionization mass spectrometric study of U-Pu-O system

    International Nuclear Information System (INIS)

    First inference from a thermal ionization mass spectrometric study of samples corresponding to the ternary U-Pu-O system, especially if high surface ionization temperatures are employed, is likely to be at variance with that from equilibrium vaporization thermodynamic studies, that the atomic species U and Pu dominate the vapor phase

  16. Gas Chromatographic Mass Spectrometric Determination of Myo-inositol in Humans Utilizing a Deuterated Internal Standard

    DEFF Research Database (Denmark)

    Andersen, Jan Rud; Larsen, Elfinn; Harbo, Helge;

    1982-01-01

    , was added as internal standard to the samples at an early stage in the analytical procedure. After separation and derivatization to the hexa-acetate, the gas chromatographic mass spectrometric analysis was carried out. A 25 m fused silica capillary column coated with methyl silicone was used, and the ions...

  17. QuEChERS sample preparation approach for mass spectrometric analysis of pesticide residues in foods

    Science.gov (United States)

    This chapter describes an easy, rapid, and low-cost sample preparation approach for the determination of pesticide residues in foods using gas and/or liquid chromatographic (GC and/or LC) analytical separation and mass spectrometric (MS) detection. The approach is known as QuEChERS, which stands fo...

  18. Mass spectrometric methods for the direct elemental and isotopic analysis of solid material

    Science.gov (United States)

    Ganeev, A. A.; Gubal, A. R.; Potapov, S. V.; Agafonova, N. N.; Nemets, V. M.

    2016-04-01

    Methods for the direct analysis of solids have a number of undeniable advantages over the methods that require preliminary dissolution of samples. High sensitivity and selectivity make the direct mass spectrometric techniques the most in-demand. The review concerns spark source mass spectrometry, laser ionization mass spectrometry, laser ablation inductively coupled plasma mass spectrometry, secondary ion mass spectrometry, secondary neutral mass spectrometry and glow discharge mass spectrometry. Basic principles, analytical characteristics and trends in the development of these techniques are discussed. Particular attention is given to applications of the techniques as well as to their competitive advantages and drawbacks. The bibliography includes 123 references.

  19. Liquid chromatography-mass spectrometric and liquid chromatography-tandem mass spectrometric determination of hallucinogenic indoles psilocin and psilocybin in "magic mushroom" samples.

    Science.gov (United States)

    Kamata, Tooru; Nishikawa, Mayumi; Katagi, Munehiro; Tsuchihashi, Hitoshi

    2005-03-01

    Accurate and sensitive analytical methods for psilocin (PC) and psilocybin (PB), tryptamine-type hallucinogens contained in "magic mushrooms," were investigated using liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The chromatographic separation on an ODS column and mass spectral information gave complete discrimination between PC and PB without derivatization. The mass spectrometric detection had a high sensitivity, and the tandem mass spectrometric detection provided more specificity and accuracy, as well as high sensitivity. The detection limits ranged from 1 to 25 pg by LC-MS in the selected ion monitoring mode, and the intra- and inter-day coefficients of variation were estimated to be 4.21-5.93% by LC-MS-MS in the selected reaction monitoring mode. By applying the present LC-MS-MS technique to four real samples, the contents of PC and PB were found to vary over a wide range (0.60-1.4 and 0.18-3.8 mg/g dry wt. for PC and PB, respectively) between samples.

  20. Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

    OpenAIRE

    Hou, Xiaolin; Roos, Per

    2008-01-01

    The radiometric methods, alpha (alpha)-, beta (beta)-, gamma (gamma)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for rad...

  1. Mass spectrometric analysis of the volatiles released by heating or crushing rocks

    Science.gov (United States)

    Barker, C.; Sommer, M. A.

    1973-01-01

    Vacuum extraction with subsequent mass spectrometric analysis of evolved volatiles was selected as the analytical procedure. The high-vacuum gas-handling system was constructed of stainless steel. The system was completely free from mercury, grease, or volatile organic materials. The furnace for heating the samples is discussed together with the high-vacuum crusher, the mass spectrometer, and approaches for water determination. The analytical procedure is considered, giving attention to the extraction of volatiles, adsorption studies, and the analysis of volatiles.

  2. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  3. Recent developments of nanoparticle-based enrichment methods for mass spectrometric analysis in proteomics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In proteome research, rapid and effective separation strategies are essential for successful protein identification due to the broad dynamic range of proteins in biological samples. Some important proteins are often expressed in ultra low abundance, thus making the pre-concentration procedure before mass spectrometric analysis prerequisite. The main purpose of enrichment is to isolate target molecules from complex mixtures to reduce sample complexity and facilitate the subsequent analyzing steps. The introduction of nanoparticles into this field has accelerated the development of enrichment methods. In this review, we mainly focus on recent developments of using different nanomaterials for pre-concentration of low-abundance peptides/ proteins, including those containing post-translational modifications, such as phosphorylation and glycosylation, prior to mass spectrometric analysis.

  4. New FORTRAN computer programs to acquire and process isotopic mass-spectrometric data

    International Nuclear Information System (INIS)

    The computer programs described in New Computer Programs to Acquire and Process Isotopic Mass Spectrometric Data have been revised. This report describes in some detail the operation of these programs, which acquire and process isotopic mass spectrometric data. Both functional and overall design aspects are addressed. The three basic program units - file manipulation, data acquisition, and data processing - are discussed in turn. Step-by-step instructions are included where appropriate, and each subsection is described in enough detail to give a clear picture of its function. Organization of file structure, which is central to the entire concept, is extensively discussed with the help of numerous tables. Appendices contain flow charts and outline file structure to help a programmer unfamiliar with the programs to alter them with a minimum of lost time

  5. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium metal

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium metal to determine compliance with specifications.

  6. Quantification of salsolinol enantiomers by stable isotope dilution liquid chromatography with tandem mass spectrometric detection

    OpenAIRE

    Cai, Min; Liu, Yi-Ming

    2008-01-01

    Salsolinol, 1-methyl-6,7-dihydroxy-2,3,4,5-tetrahydroisoquinoline (SAL), is a precursor of a Parkinsonian neurotoxin, N-methysalsolinol (N-methyl-SAL). Previous studies have shown that individual enantiomers of N-methyl-SAL possess distinct neurotoxicological properties. In this work, a chiral high-performance liquid chromatography (HPLC) method with electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the quantification of (R/S)-SAL enantiomers. Enantiose...

  7. Mass Spectrometric Detection of Nanoparticle Host–Guest Interactions in Cells

    OpenAIRE

    Yan, Bo; Yesilbag Tonga, Gulen; Hou, Singyuk; Fedick, Patrick W.; Yeh, Yi-Cheun; Alfonso, Felix S.; Mizuhara, Tsukasa; Vachet, Richard W.; Rotello, Vincent M.

    2014-01-01

    Synthetic host–guest chemistry is a versatile tool for biomedical applications. Characterization and detection of host–guest complexes in biological systems, however, is challenging due to the complexity of the biological milieu. Here, we describe and apply a mass spectrometric method to monitor the association and dissociation of nanoparticle (NP)-based host–guest interactions that integrates NP-assisted laser desorption/ionization (LDI) and matrix assisted laser desoption/ionization (MALDI)...

  8. Mass spectrometric studies on irradiated (U, Pu) mixed carbide fuel of Fbtr

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, R. [Fuel Chemistry Division, IGCAR, Kalpakkam 603 102, Tamil Nadu (India)]. E-mail: rbs@igcar.ernet.in; Darwin Albert Raj, D.; Nalini, S.; Sai Baba, M. [Fuel Chemistry Division, IGCAR, Kalpakkam 603 102, Tamil Nadu (India)

    2005-07-01

    Mass spectrometry was employed to characterise the irradiated mixed carbide fuel of fast breeder test reactor (FBTR) for assessing its performance: thermal ionisation mass spectrometry to determine the isotopic composition, concentrations of U, Pu and Nd in the dissolver solutions and to deduce the burn-up, and a quadrupole mass spectrometric system to obtain the percentage release of fission gases (Kr + Xe). A summary and analysis of the results obtained with the fuel at 25,000 and 50,000 MWd/t in these studies is given in this paper. (author)

  9. MALDI-TOF mass spectrometric identification of dyes and pigments.

    Science.gov (United States)

    Soltzberg, L J; Hagar, Amanda; Kridaratikorn, Supicha; Mattson, Anne; Newman, Richard

    2007-11-01

    We have used MALDI-TOF mass spectrometry to characterize a selection of dyes from the Schweppe dye collection and pigments from the Tate Gallery collection. MALDI-TOF mass spectra of such samples are easily obtained and, through observation of both positive and negative ion spectra, provide a convenient, versatile method for dye characterization and identification. Such pairs of positive and negative ion spectra immediately distinguish between acidic and basic dyes and provide the characteristic mass of either the molecular ion or a simply related fragment ion. This approach is especially useful in situations where very small amounts of analyte are available, as in museum research and forensic analysis. In the case of textile dyes, we have carried out identification on material from single fibers and, with insoluble pigments, have begun to identify components of historically important pastel sticks from submicrogram samples.

  10. Mass spectrometric studies of the cluster formation of radon progeny

    International Nuclear Information System (INIS)

    A new experimental system is developed to study the cluster formation of radon progeny with neutral molecules in the environment, which includes a modified mass spectrometer and a surface barrier detector. With the system, the cluster research is carried out at molecular level at which the mass of individual cluster formed is measured. A theory is also proposed to treat the cluster formation as a discrete process based on the ion-dipole and dipole-dipole interactions. Comparison between the theory and experiment is given. (author). 16 refs., 6 figs

  11. Mass spectrometric studies on the interaction of cisplatin and insulin.

    Science.gov (United States)

    Li, Jing; Yue, Lei; Liu, Yaqin; Yin, Xinchi; Yin, Qi; Pan, Yuanjiang; Yang, Lirong

    2016-04-01

    The interaction of antitumor drug, cisplatin (cis-[PtCl2(NH3)2], CDDP) with insulin from porcine pancreas has been investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high resolution hybrid ion trap/time-of-flight mass spectrometry (MALIDI-TOF/TOF-MS and ESI-IT/TOF MS). The MALDI-TOF/TOF-MS results demonstrated that the presence of cisplatin complex resulted in the reduction of the disulfide bond in porcine pancreas after the incubations of the two substances were performed in vitro. It indicated that the presence of cisplatin would destroy the native configuration of insulin, which may lead to the inactivation of insulin. High resolution mass values and the characteristic isotopic pattern of the platinated insulin ions allowed the analysis of platinated mono-, di- and triadducts of cisplatin and insulin in the incubations under different conditions. The laser-induced dissociation of the monoadduct obtained in MALDI source was carried out and one platinum was found to bind to insulin B chain was determined. The platinum binding sites were further identified to be the N terminus (B chain), cysteine 7 (B chain) and cysteine 19 (B chain) residues by electrospray ionization tandem mass spectrometry. The identification of the interaction between insulin and cisplatin broadens the horizon of the knowledge in the interaction of the proteins and metallodrugs. PMID:26724920

  12. Mass-spectrometric exploration of proteome structure and function

    DEFF Research Database (Denmark)

    Aebersold, Ruedi; Mann, Matthias

    2016-01-01

    , the structures and functions of selected proteins have been studied using biochemical and biophysical methods. However, the properties and behaviour of the proteome as an integrated system have largely remained elusive. Powerful mass-spectrometry-based technologies now provide unprecedented insights...

  13. Mass Spectrometric Monitoring of Animal Feed for BSE Spread

    Science.gov (United States)

    King, Angela G.

    2004-01-01

    The researchers in London have developed an emerging technology that utilizes mass spectrometry to detect processed animal protein (PAP) in animal feed. The amount of animal protein in the feed can be determined by the ratio of the hydrolyzed gelatine signal at m/z 1044 to an internal standard signal at m/z 556.

  14. Extending the frontiers of mass spectrometric instrumentation and methods

    Energy Technology Data Exchange (ETDEWEB)

    Schieffer, Gregg Martin [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    The focus of this dissertation is two-fold: developing novel analysis methods using mass spectrometry and the implementation and characterization of a novel ion mobility mass spectrometry instrumentation. The novel mass spectrometry combines ion trap for ion/ion reactions coupled to an ion mobility cell. The long term goal of this instrumentation is to use ion/ion reactions to probe the structure of gas phase biomolecule ions. The three ion source - ion trap - ion mobility - qTOF mass spectrometer (IT - IM - TOF MS) instrument is described. The analysis of the degradation products in coal (Chapter 2) and the imaging plant metabolites (Appendix III) fall under the methods development category. These projects use existing commercial instrumentation (JEOL AccuTOF MS and Thermo Finnigan LCQ IT, respectively) for the mass analysis of the degraded coal products and the plant metabolites, respectively. The coal degradation paper discusses the use of the DART ion source for fast and easy sample analysis. The sample preparation consisted of a simple 50 fold dilution of the soluble coal products in water and placing the liquid in front of the heated gas stream. This is the first time the DART ion source has been used for analysis of coal. Steven Raders under the guidance of John Verkade came up with the coal degradation projects. Raders performed the coal degradation reactions, worked up the products, and sent them to me. Gregg Schieffer developed the method and wrote the paper demonstrating the use of the DART ion source for the fast and easy sample analysis. The plant metabolite imaging project extends the use of colloidal graphite as a sample coating for atmospheric pressure LDI. DC Perdian and I closely worked together to make this project work. Perdian focused on building the LDI setup whereas Schieffer focused on the MSn analysis of the metabolites. Both Perdian and I took the data featured in the paper. Perdian was the primary writer of the paper and used it as a

  15. Detection of Candida albicans by mass spectrometric fingerprinting.

    Science.gov (United States)

    Zehm, Sarah; Schweinitz, Simone; Würzner, Reinhard; Colvin, Hans Peter; Rieder, Josef

    2012-03-01

    Candida albicans is one of the most frequent causes of fungal infections in humans. Significant correlation between candiduria and invasive candidiasis has previously been described. The existing diagnostic methods are often time-consuming, cost-intensive and lack in sensitivity and specificity. In this study, the profile of low-molecular weight volatile compounds in the headspace of C. albicans-urine suspensions of four different fungal cell concentrations compared to nutrient media and urine without C. albicans was determined using proton-transfer reaction mass spectrometry (PTR-MS). At fungal counts of ≥1.5 × 10(5) colony forming units (CFU)/ml signals at 45, 47 and 73 atomic mass units (amu) highly significantly increased. At fungal counts of albicans-urine suspensions of different fungal cell concentrations. PTR-MS represents a promising approach to rapid, highly sensitive and non-invasive clinical diagnostics allowing qualitative and quantitative analysis.

  16. Mass spectrometric analysis with cluster projectiles and coincidence counting

    Energy Technology Data Exchange (ETDEWEB)

    Cox, B.D.

    1992-01-01

    Methods for maximizing the amount of secondary ion information, per primary projectile, are described. The method is based on time-of-flight mass spectrometry and event-by-event coincidence counting. The information obtained from coincidence counting time-of-flight mass spectrometry includes: (a) surface composition, (b) relative concentrations, and (c) degree of intermolecular mixing. The technique was applied to the study of an important new class of polymers: polymer blends. Secondary ion mass spectrometry, when applied to the analysis of synthetic polymers, induces backbone fragmentation which is characteristic of the homopolymer. The characteristic fingerprint peaks from polystyrene and poly(vinyl methyl ether) were used to identify the presence of these two polymers in a polymer blend. The percent coincidence between the characteristic secondary ions from each component of the blend were used to determine both the relative concentration and the degree of molecular mixing. Results indicate molecular segregation of the two polymers on the film surface. The largest degree of segregation was determined for the phase separated blends. The performance of this technique depends on the desorption efficiency of the primary projectiles. In practice one seeks primary ions which are surface sensitive, have controllable parameters such as size, velocity, and charge state, and generate high secondary ion yields. Focus was placed on the use of keV organic cluster projectiles to meet these criteria. Of interest to this study were C[sub 18] (chrysene), C[sub 24] (coronene), and C[sub 60] (buckminster-fulleren). Results indicate enhanced secondary ion yields for C[sub 60]. For example, when CsI is bombarded with 30 keV C[sub 60], the yields for I[sup [minus

  17. Extraction-mass spectrometric determination of platinum metals in materials of complex composition

    International Nuclear Information System (INIS)

    A method is developed for the extraction mass-spectrometric determination of platinum metals, including ruthenium. The loWer limit of detectable contents is 1.6x10-6 mass.% (a coefficient of concentration is 50). The relative standard deviation is 0.19-0.38. Relative sensitivity coefficients determined experimentally with the aid of reference samples for platinum metals enable the systematic errors of analysis results to be taken into account. The method is most advisably used for the simultaneous determination of platinum metals in complex objects (minerals, rocks, etc.)

  18. Terverticillate Penicillia studied by direct electrospray mass spectrometric profiling of crude extracts: I. Chemosystematics

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn; Frisvad, Jens Christian

    1997-01-01

    mass profile, but a noise level was applied. Cluster analysis using the correlation coefficient resulted in dendrograms where approximately 75% of the included taxa could be considered segregated in distinct clusters. Standard normalized data (mass spectra) resulted in clear clusters, but grouped taxa......A chemosystematic study of 339 isolates from all known terverticillate Penicillium taxa was performed using electrospray mass spectrometric analysis of extractable metabolites. The mass profiles were made by injecting crude plug extracts made from cultures grown on Czapek Yeast Autolysate agar (CYA......) and Yeast Extract Sucrose agar (YES) directly into the electrospray source of the mass spectrometer. A data matrix was made from each substrate by transferring the complete centroid mass spectrum from 200 to 700 amu as 501 variables to individual columns. No attempt was made to identify ions in the...

  19. Mass spectrometric measurements of the isotopic anatomies of molecules (Invited)

    Science.gov (United States)

    Eiler, J. M.; Krumwiede, D.; Schlueter, H.

    2013-12-01

    Site-specific and multiple isotopic substitutions in molecular structures potentially provide an extraordinarily rich set of constraints on their sources, conditions of formation, reaction and transport histories, and perhaps other issues. Examples include carbonate ';clumped isotope' thermometry, clumped isotope measurements of CO2, O2, and, recently, methane, ethane and N2O; site-specific 15N measurements in N2O and 13C and D analyses of fatty acids, sugars, cellulose, food products, and, recently, n-alkanes. Extension of the principles behind these tools to the very large number of isotopologues of complex molecules could potentially lead to new uses of isotope chemistry, similar to proteomics, metabolomics and genomics in their complexity and depth of detail (';isotomics'?). Several technologies are potentially useful for this field, including ';SNIF-NMR', gas source mass spectrometry and IR absorption spectroscopy. However, all well established methods have restrictive limits in the sizes of samples, types of analyzes, and the sorts of isotopologues that can be measured with useful precision. We will present an overview of several emerging instruments and techniques of high-resolution gas source mass spectrometry that may enable study of a large proportion of the isotopologues of a wide range of volatile and semi-volatile compounds, including many organics, with precisions and sample sizes suitable for a range of applications. A variety of isotopologues can be measured by combining information from the Thermo 253 Ultra (a new high resolution, multi-collector gas source mass spectrometer) and the Thermo DFS (a very high resolution single collector, but used here on a novel mode to achieve ~per mil precision ratio measurements), sometimes supplemented by conventional bulk isotopic measurements. It is possible to design methods in which no one of these sources of data meaningfully constrain abundances of specific isotopologues, but their combination fully and

  20. A mass spectrometric-derived cell surface protein atlas.

    Directory of Open Access Journals (Sweden)

    Damaris Bausch-Fluck

    Full Text Available Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa. The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments.

  1. A mass spectrometric-derived cell surface protein atlas.

    Science.gov (United States)

    Bausch-Fluck, Damaris; Hofmann, Andreas; Bock, Thomas; Frei, Andreas P; Cerciello, Ferdinando; Jacobs, Andrea; Moest, Hansjoerg; Omasits, Ulrich; Gundry, Rebekah L; Yoon, Charles; Schiess, Ralph; Schmidt, Alexander; Mirkowska, Paulina; Härtlová, Anetta; Van Eyk, Jennifer E; Bourquin, Jean-Pierre; Aebersold, Ruedi; Boheler, Kenneth R; Zandstra, Peter; Wollscheid, Bernd

    2015-01-01

    Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome) of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC) technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA) providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa). The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments. PMID:25894527

  2. Mass Spectrometric Screening of Ovarian Cancer with Serum Glycans

    Directory of Open Access Journals (Sweden)

    Jae-Han Kim

    2014-01-01

    Full Text Available Changes of glycosylation pattern in serum proteins have been linked to various diseases including cancer, suggesting possible development of novel biomarkers based on the glycomic analysis. In this study, N-linked glycans from human serum were quantitatively profiled by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF mass spectrometry (MS and compared between healthy controls and ovarian cancer patients. A training set consisting of 40 healthy controls and 40 ovarian cancer cases demonstrated an inverse correlation between P value of ANOVA and area under the curve (AUC of each candidate biomarker peak from MALDI-TOF MS, providing standards for the classification. A multibiomarker panel composed of 15 MALDI-TOF MS peaks resulted in AUC of 0.89, 80~90% sensitivity, and 70~83% specificity in the training set. The performance of the biomarker panel was validated in a separate blind test set composed of 23 healthy controls and 37 ovarian cancer patients, leading to 81~84% sensitivity and 83% specificity with cut-off values determined by the training set. Sensitivity of CA-125, the most widely used ovarian cancer marker, was 74% in the training set and 78% in the test set, respectively. These results indicate that MALDI-TOF MS-mediated serum N-glycan analysis could provide critical information for the screening of ovarian cancer.

  3. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The standard covers analytical procedures to determine compliance of nuclear-grade boron carbide powder and pellets to specifications. The following methods are described in detail: total carbon by combustion and gravimetry; total boron by titrimetry; isotopic composition by mass spectrometry; chloride and fluoride separation by pyrohydrolysis; chloride by constant-current coulometry; fluoride by ion-selective electrode; water by constant-voltage coulometry; impurities by spectrochemical analysis; soluble boron by titrimetry; soluble carbon by a manometric measurement; metallic impurities by a direct reader spectrometric method. (JMT)

  4. Mass Spectrometric Detection of Bacterial Protein Toxins and Their Enzymatic Activity.

    Science.gov (United States)

    Kalb, Suzanne R; Boyer, Anne E; Barr, John R

    2015-08-31

    Mass spectrometry has recently become a powerful technique for bacterial identification. Mass spectrometry approaches generally rely upon introduction of the bacteria into a matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometer with mass spectrometric recognition of proteins specific to that organism that form a reliable fingerprint. With some bacteria, such as Bacillus anthracis and Clostridium botulinum, the health threat posed by these organisms is not the organism itself, but rather the protein toxins produced by the organisms. One such example is botulinum neurotoxin (BoNT), a potent neurotoxin produced by C. botulinum. There are seven known serotypes of BoNT, A-G, and many of the serotypes can be further differentiated into toxin variants, which are up to 99.9% identical in some cases. Mass spectrometric proteomic techniques have been established to differentiate the serotype or toxin variant of BoNT produced by varied strains of C. botulinum. Detection of potent biological toxins requires high analytical sensitivity and mass spectrometry based methods have been developed to determine the enzymatic activity of BoNT and the anthrax lethal toxins produced by B. anthracis. This enzymatic activity, unique for each toxin, is assessed with detection of the toxin-induced cleavage of strategically designed peptide substrates by MALDI-TOF mass spectrometry offering unparalleled specificity. Furthermore, activity assays allow for the assessment of the biological activity of a toxin and its potential health risk. Such methods have become important diagnostics for botulism and anthrax. Here, we review mass spectrometry based methods for the enzymatic activity of BoNT and the anthrax lethal factor toxin.

  5. Assessment of current mass spectrometric workflows for the quantification of low abundant proteins and phosphorylation sites

    Directory of Open Access Journals (Sweden)

    Manuel Bauer

    2015-12-01

    Full Text Available The data described here provide a systematic performance evaluation of popular data-dependent (DDA and independent (DIA mass spectrometric (MS workflows currently used in quantitative proteomics. We assessed the limits of identification, quantification and detection for each method by analyzing a dilution series of 20 unmodified and 10 phosphorylated synthetic heavy labeled reference peptides, respectively, covering six orders of magnitude in peptide concentration with and without a complex human cell digest background. We found that all methods performed very similarly in the absence of background proteins, however, when analyzing whole cell lysates, targeted methods were at least 5–10 times more sensitive than directed or DDA methods. In particular, higher stage fragmentation (MS3 of the neutral loss peak using a linear ion trap increased dynamic quantification range of some phosphopeptides up to 100-fold. We illustrate the power of this targeted MS3 approach for phosphopeptide monitoring by successfully quantifying 9 phosphorylation sites of the kinetochore and spindle assembly checkpoint component Mad1 over different cell cycle states from non-enriched pull-down samples. The data are associated to the research article ‘Evaluation of data-dependent and data-independent mass spectrometric workflows for sensitive quantification of proteins and phosphorylation sites׳ (Bauer et al., 2014 [1]. The mass spectrometry and the analysis dataset have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org via the PRIDE partner repository with the dataset identifier PXD000964.

  6. Determination of trace quantities of uranium in rocks mass spectrometric isotope dilution technique

    International Nuclear Information System (INIS)

    A detailed experimental investigation on the thermionic emission of uranium deposited on a single flat type rhenium filament has been carried out. The study was aimed at determining the influence of various forms of deposition on the emission sensitivity and thermal stability of U+ , UO+ and UO2+ ions. Based on these investigations, a technique, involving an addition of a small quantity of colloidal suspension of graphite on top of the uranyl nitrate sample deposited, was chosen because of its higher, emission sensitivity for uranium metal ions. The experimental parameters of the technique were optimised and the technique was employed in the determination of trace quantities of uranium in rock samples using mass spectrometric isotope dilution method. For the mass spectrometric isotope dilution analysis National Bureau of Standards uranium isotopic standard NBS-U 970 was employed as a tracer, where as the mass discrimination effect in the uranium isotope analysis was corrected using the uranium isotopic standard NBS-U500. Uranium was determined in each of the seven granite samples from Wyoming, USA and two USGS standard rocks. The precision of the analysis was found to be ±1% . The uranium values obtained on the rock samples were compared with the analyses of other investigators. Influence of the sample splitting on the uranium analysis was discussed in the light of the analytical results obtained.(author)

  7. GNU polyxmass: a software framework for mass spectrometric simulations of linear (bio-polymeric analytes

    Directory of Open Access Journals (Sweden)

    Rusconi Filippo

    2006-04-01

    Full Text Available Abstract Background Nowadays, a variety of (bio-polymers can be analyzed by mass spectrometry. The detailed interpretation of the spectra requires a huge number of "hypothesis cycles", comprising the following three actions 1 put forth a structural hypothesis, 2 test it, 3 (invalidate it. This time-consuming and painstaking data scrutiny is alleviated by using specialized software tools. However, all the software tools available to date are polymer chemistry-specific. This imposes a heavy overhead to researchers who do mass spectrometry on a variety of (bio-polymers, as each polymer type will require a different software tool to perform data simulations and analyses. We developed a software to address the lack of an integrated software framework able to deal with different polymer chemistries. Results The GNU polyxmass software framework performs common (bio-chemical simulations–along with simultaneous mass spectrometric calculations–for any kind of linear bio-polymeric analyte (DNA, RNA, saccharides or proteins. The framework is organized into three modules, all accessible from one single binary program. The modules let the user to 1 define brand new polymer chemistries, 2 perform quick mass calculations using a desktop calculator paradigm, 3 graphically edit polymer sequences and perform (bio-chemical/mass spectrometric simulations. Any aspect of the mass calculations, polymer chemistry reactions or graphical polymer sequence editing is configurable. Conclusion The scientist who uses mass spectrometry to characterize (bio-polymeric analytes of different chemistries is provided with a single software framework for his data prediction/analysis needs, whatever the polymer chemistry being involved.

  8. Mass-spectrometric determination of trace elements in aqueous media without preconcentration

    Energy Technology Data Exchange (ETDEWEB)

    Foss, G. O.

    1981-10-01

    Feasibility of using a low pressure glow discharge as an ion source for the mass spectrometric determination of trace elements in aqueous media was investigated. A cryogenically cooled hollow cathode ion source was developed to analyze aqueous samples without external preconcentration. Aqueous solutions containing seventy elements were analyzed and the detection limits, sensitivity factors, and linear regression correlation coefficients were determined. A standard test solution of trace elements in water was analyzed and the concentrations of trace elements were calculated using the sensitivity factors determined previously. The results compared favorably within the error limits predicted by the semiquantitative survey methods used. Tap water and natural lake water samples were examined and minimal interference effects due to organic compounds and biological compounds were noted. A research ion optical system (RIOS) was developed as a flexible mass analyzer for the development of new ion sources. The RIOS is a double focussing mass analyzer designed utilizing the Mattauch-Herzog geometry with externally adjustable slit assemblies.

  9. Mass spectrometric identification of proteins and characterization of their post-translational modifications in proteome analysis

    DEFF Research Database (Denmark)

    Roepstorff, P; Larsen, Martin Røssel

    2001-01-01

    more than 425.000 protein sequences. However, the cellular functions are determined by the set of proteins expressed in the cell--the proteome. Two-dimensional gel electrophoresis, mass spectrometry and bioinformatics have become important tools in correlating the proteome with the genome. The current...... dominant strategies for identification of proteins from gels based on peptide mass spectrometric fingerprinting and partial sequencing by mass spectrometry are described. After identification of the proteins the next challenge in proteome analysis is characterization of their post-translational...... modifications. The general problems associated with characterization of these directly from gel separated proteins are described and the current state of art for the determination of phosphorylation, glycosylation and proteolytic processing is illustrated....

  10. The Bremen mass spectrometric facility for the measurement of helium isotopes, neon, and tritium in water.

    Science.gov (United States)

    Sültenfuss, Jürgen; Roether, Wolfgang; Rhein, Monika

    2009-06-01

    We describe the mass spectrometric facility for measuring helium isotopes, neon, and tritium that has been operative at this institute since 1989, and also the sampling and sample preparation steps that precede the mass spectrometric analysis. For water samples in a near-equilibrium with atmospheric air, the facility achieves precision for (3)He/(4)He ratios of+/-0.4% or better, and+/-0.8 % or better for helium and neon concentrations. Tritium precision is typically+/-3 % and the detection limit 10 mTU ( approximately 1.2.10(-3) Bq/kg of pure water). Sample throughputs can reach some thousands per year. These achievements are enabled, among other features, by automation of the measurement procedure and by elaborate calibration, assisted by continual development in detail. To date, we have measured more than 15,000 samples for tritium and 23,000 for helium isotopes and neon, mostly in the context of oceanographic and hydrologic work. Some results of such work are outlined. Even when atmospheric tritium concentrations have become rather uniform, tritium provides water ages if (3)He data are taken concurrently. The technique can resolve tritium concentrations in waters of the pre-nuclear era.

  11. MALDI mass spectrometric imaging meets "omics": recent advances in the fruitful marriage.

    Science.gov (United States)

    Crecelius, A C; Schubert, U S; von Eggeling, F

    2015-09-01

    Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI MSI) is a method that allows the investigation of the molecular content of surfaces, in particular, tissues, within its morphological context. The applications of MALDI MSI in the field of large-scale mass spectrometric studies, which are typically denoted by the suffix "omics", are steadily increasing. This is because, on the one hand, technical advances regarding sample collection and preparation, matrix application, instrumentation, and data processing have enhanced the molecular specificity and sensitivity of MALDI MSI; on the other hand, the focus of the "omics" community has moved from establishing an inventory of certain compound classes to exploring their spatial distribution to gain novel insights. Thus, the aim of this mini-review is twofold, to display the state-of-the-art in terms of technical aspects in MALDI MSI and to highlight selected applications in the last two years, which either have significantly advanced a certain "omics" field or have introduced a new one through pioneering efforts. PMID:26161715

  12. Mass Spectrometric Calibration of Controlled Fluoroform Leak Rate Devices Technique and Uncertainty Analysis

    CERN Document Server

    Balsley, S D; Laduca, C A

    2003-01-01

    Controlled leak rate devices of fluoroform on the order of 10 sup - sup 8 atm centre dot cc sec sup - sup 1 at 25 C are used to calibrate QC-1 War Reserve neutron tube exhaust stations for leak detection sensitivity. Close-out calibration of these tritium-contaminated devices is provided by the Gas Dynamics and Mass Spectrometry Laboratory, Organization 14406, which is a tritium analytical facility. The mass spectrometric technique used for the measurement is discussed, as is the first principals calculation (pressure, volume, temperature and time). The uncertainty of the measurement is largely driven by contributing factors in the determination of P, V and T. The expanded uncertainty of the leak rate measurement is shown to be 4.42%, with a coverage factor of 3 (k=3).

  13. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  14. Mass spectrometric behaviour of carboxylated polyethylene glycols and carboxylated octylphenol ethoxylates.

    Science.gov (United States)

    Frańska, Magdalena; Zgoła, Agnieszka; Rychłowska, Joanna; Szymański, Andrzej; Łukaszewski, Zenon; Frański, Rafał

    2003-01-01

    Mass spectrometric behaviour of mono- and di-carboxylated polyethylene glycols (PEGCs and CPEGCs) and carboxylated octylphenol ethoxylates (OPECs) are discussed. The tendency for ionisation (deprotonation, protonation and cationisation by alkali metal cations) of carboxylated PEGs was compared with that of non-carboxylated correspondents by using both secondary ion mass spectrometry (SIMS) and electrospray ionisation (ESI). The fragmentation of the PEGCs and CPEGCs is discussed and also compared with their neutral correspondents, PEGs. The B/E mass spectra were recorded, using secondary ion mass spectrometry as a method for generation, for deprotonated and protonated molecules and molecules cationised by alkali metal cations. The fragmentation behaviour of PEGs is found to be different from that of CPEGCs, The presence of carboxylic groups may be confirmed not only by the determination of molecular weights of the ethoxylates studied, but also on the basis of the fragment ions formed. The metastable decomposition of the [OPEC-H](-) ions proceed through the cleavage of the bond between the octylphenol moiety and the ethoxylene chain leading to the octylphenoxy anions. It permits determination of the mass of the hydrophobic moiety of the studied carboxylated alkylphenol ethoxylate. ESI mass spectra recorded in the negative ion mode were found to be more suitable for the determination of the average molecular weight of carboxylated ethoxylates than SI mass spectra. PMID:12939494

  15. Identifying tissue-specific signal variation in MALDI mass spectrometric imaging by use of an internal standard

    NARCIS (Netherlands)

    Pirman, D.A.; Kiss, A.; Heeren, R.M.A.; Yost, R.A.

    2013-01-01

    Generating analyte-specific distribution maps of compounds in a tissue sample by matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) has become a useful tool in numerous areas across the biological sciences. Direct analysis of the tissue sample provides MS images of

  16. XMS: Cross-Platform Normalization Method for Multimodal Mass Spectrometric Tissue Profiling

    Science.gov (United States)

    Golf, Ottmar; Muirhead, Laura J.; Speller, Abigail; Balog, Júlia; Abbassi-Ghadi, Nima; Kumar, Sacheen; Mróz, Anna; Veselkov, Kirill; Takáts, Zoltán

    2015-01-01

    Here we present a proof of concept cross-platform normalization approach to convert raw mass spectra acquired by distinct desorption ionization methods and/or instrumental setups to cross-platform normalized analyte profiles. The initial step of the workflow is database driven peak annotation followed by summarization of peak intensities of different ions from the same molecule. The resulting compound-intensity spectra are adjusted to a method-independent intensity scale by using predetermined, compound-specific normalization factors. The method is based on the assumption that distinct MS-based platforms capture a similar set of chemical species in a biological sample, though these species may exhibit platform-specific molecular ion intensity distribution patterns. The method was validated on two sample sets of (1) porcine tissue analyzed by laser desorption ionization (LDI), desorption electrospray ionization (DESI), and rapid evaporative ionization mass spectrometric (REIMS) in combination with Fourier transformation-based mass spectrometry; and (2) healthy/cancerous colorectal tissue analyzed by DESI and REIMS with the latter being combined with time-of-flight mass spectrometry. We demonstrate the capacity of our method to reduce MS-platform specific variation resulting in (1) high inter-platform concordance coefficients of analyte intensities; (2) clear principal component based clustering of analyte profiles according to histological tissue types, irrespective of the used desorption ionization technique or mass spectrometer; and (3) accurate "blind" classification of histologic tissue types using cross-platform normalized analyte profiles.

  17. MASS SPECTROMETRIC ANALYSIS FOR THE IDENTIFICATION OF THUNNUS GENUS FOUR SPECIES

    Directory of Open Access Journals (Sweden)

    T. Pepe

    2011-01-01

    Full Text Available An accurate identification of similar fish species is necessary to prevent illegal substitution and is imposed by labeling regulations in UE countries (1. The genus Thunnus comprises many species of different quality and commercial value. The increasing trade of fish preparations of the species included in this genus and the consequent loss of the external anatomical and morphological features enables fraudulent substitutions. This study reports data relating to the proteomic analysis of four tuna species (T. thynnus, T. alalunga, T. albacares, T. obesus. Sarcoplasmic proteins were studied by mono and two dimensional electrophoresis. The most significant proteins for the characterization of the species were analyzed by mass spectrometric techniques. As reported in a previous study (2, an accurate identification of the species seems possible, owing to the polymorphism displayed by the species of the Thunnus genus.

  18. Determination of Mass Spectrometric Sensitivity of Different Metalloporphyrin Esters Relative to Porphyrin Ester

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Møller, J.;

    1977-01-01

    Quantitative determination of metalloporphyrin contamination in preparations of biologically important porphyrins was achieved mass spectrometrically by application of the integrated ion current technique. For this purpose, the relative molecular ion sensitivities of the contaminating metal...... complexes were determined from the ratios of the integrated molecular ion currents of a series of calibration samples containing a porphyrin ester and one of its metal complexes in known molar ratio. Complexes formed with divalent ions of Cu, Zn, Fe, Co and Ni of copro- as well as uro......-prophyrin permethylester were all found to have the same molecular ion sensitivities as their metal-free porphyrin ester. The relative metalloporphyrin ester content in a sample of porphyrin ester was thus obtained directly as the integrated ion current ratios of the normalized molecular ions. The preparation of...

  19. Mass spectrometric imaging of flavonoid glycosides and biflavonoids in Ginkgo biloba L.

    Science.gov (United States)

    Beck, Sebastian; Stengel, Julia

    2016-10-01

    Ginkgo biloba L. is known to be rich in flavonoids and flavonoid glycosides. However, the distribution within specific plant organs (e.g. within leaves) is not known. By using HPLC-MS and MS/MS we have identified a number of previously known G. biloba flavonoid glycosides and biflavonoids from leaves. Namely, kaempferol, quercetin, isorhamnetin, myricetin, laricitrin/mearnsetin and apigenin glycosides were identified. Furthermore, biflavonoids like ginkgetin/isoginkgetin were also detected. The application of MALDI mass spectrometric imaging, enabled the compilation of concentration profiles of flavonoid glycosides and biflavonoids in G. biloba L. leaves. Both, flavonoid glycosides and biflavonoids show a distinct distribution in leaf thin sections of G. biloba L. PMID:27233155

  20. Molecular beam mass spectrometric sampling of minor species from coal dust-air flames

    International Nuclear Information System (INIS)

    It has been demonstrated that unaugmented, unconfined, premixed coal dust-air flames can be stabilized on small conical or flat, Meeker type burners. Since these flames are laminar, they can be used to study the kinetics of various processes in coal combustion and related areas such as understanding mechanisms of fireside corrosion and of flame and explosive inhibition. Some of the current work with these flames is directed toward identification and measurement of minor alkali metal and other species responsible for fireside corrosion. In order to make these measurements, molecular beam mass spectrometric sampling techniques have been adpated for use with these heterogeneous flames. In this paper, the equipment and techniques used are reviewed and some preliminary results presented

  1. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  2. New fortran computer programs to acquire and process isotopic mass spectrometric data

    International Nuclear Information System (INIS)

    This report describes in some detail the operation of newly written programs that acquire and process isotopic mass spectrometric data. Both functional and overall design aspects are addressed. The three basic program units - file manipulation, data acquisition, and data processing - are discussed in turn. Step-by-step instructions are included where appropriate, and each subsection is described in enough detail to give a clear picture of its function. Organization of the file structure, which is central to the entire concept, is extensively discussed with the help of numerous tables. Appendices contain flow charts and definitions of variables to help a programmer unfamiliar with the programs to alter them with a minimum of lost time. 12 figures, 17 tables

  3. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples.

  4. Spatial correlation of confocal Raman scattering and secondary ion mass spectrometric molecular images of lignocellulosic materials.

    Science.gov (United States)

    Li, Zhen; Chu, Li-Qiang; Sweedler, Jonathan V; Bohn, Paul W

    2010-04-01

    A detailed chemical and structural understanding of pre-enzymatic processing of lignocellulosic materials (LCMs) is a key objective in the development of renewable energy. Efficient rendering of biomass components into fermentable substrates for conversion into biofuel feedstocks would benefit greatly from the development of new technologies to provide high-quality, spatially resolved chemical information about LCMs during the various processing states. In an effort to realize this important goal, spatially correlated confocal Raman and mass spectrometric images allow the extraction of three-dimensional information from the perennial grass, Miscanthus x giganteus. An optical microscopy-based landmark registry scheme was developed that allows samples to be transferred between laboratories at different institutions, while retaining the capability to access the same physical regions of the samples. Subsequent to higher resolution imaging via confocal Raman microscopy and secondary ion mass spectrometry (SIMS), laser desorption-ionization mass spectrometry was used to place these regions within the overall sample architecture. Excellent sample registry was evident in the highly correlated Raman and SIMS images. In addition, the correlation of vibrational Raman scattering with mass spectra from specific spatial locations allowed confirmation of the assignment of intracellular globular structures to hemicellulose-rich lignin complexes, an assignment which could only be made tentatively from either image alone. PMID:20205411

  5. Activity-Based Costing Application in an Urban Mass Transport Company

    OpenAIRE

    Popesko Boris; Novák Petr

    2011-01-01

    The purpose of this paper is to provide a basic overview of the application of Activity-Based Costing in an urban mass transport company which operates land public transport via buses and trolleys within the city. The case study was conducted using the Activity-Based Methodology in order to calculate the true cost of individual operations and to measure the profitability of particular transport lines. The case study analysis showed the possible effects of the application of the Activity-Based...

  6. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  7. Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide-related peptides.

    Science.gov (United States)

    Sweedler, J V; Li, L; Floyd, P; Gilly, W

    2000-12-01

    A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) survey of the major peptides in the stellar, fin and pallial nerves and the posterior chromatophore lobe of the cephalopods Sepia officinalis, Loligo opalescens and Dosidicus gigas has been performed. Although a large number of putative peptides are distinct among the three species, several molecular masses are conserved. In addition to peptides, characterization of the lipid content of the nerves is reported, and these lipid peaks account for many of the lower molecular masses observed. One conserved set of peaks corresponds to the FMRFamide-related peptides (FRPs). The Loligo opalescens FMRFa gene has been sequenced. It encodes a 331 amino acid residue prohormone that is processed into 14 FRPs, which are both predicted by the nucleotide sequence and confirmed by MALDI MS. The FRPs predicted by this gene (FMRFa, FLRFa/FIRFa and ALSGDAFLRFa) are observed in all three species, indicating that members of this peptide family are highly conserved across cephalopods. PMID:11060217

  8. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Uranium dioxide is used as a nuclear-reactor fuel. In order to be suitable for this purpose, the material must meet certain criteria for uranium content, stoichiometry, isotopic composition, impurity content. The following analytical procedures, which are described in detail, are designed to show whether or not a given material meets specifications: uranium by ferrous sulfate reduction in phosphoric acid and dichromate titration method; uranium and oxygen uranium atomic ratio by the ignition (gravimetric) impurity correction method; oxygen to uranium atomic ratios by the polarographic method; carbon (total) by direct combustion-thermal conductivity method; total chlorine and fluorine by pyrohydrolysis ion-selective electrode method; moisture by the coulometric, electrolytic moisture analyzer method; nitrogen by the Kjeldahl method; total sulfur by distillation-spectrophotometric method; isotopic uranium composition by multiple-filament surface-ionization mass spectrometric method; spectrochemical determination of trace elements in high-purity uranium dioxide; volatile fluoride impurities by spectrochemical method using the rotating-disk spark technique; spectrochemical determination of silver by gallium oxide carrier D-C arc technique; rare earths by copper spark-spectrochemical method; impurity elements by a spark-source mass spectrographic method; surface area by nitrogen absorption method; total gas in reactor-grade uranium dioxide pellets; thorium and rare earth elements by spectroscopy; hydrogen by inert gas fusion; and uranium isotopic analysis by mass spectrometry. (JMT)

  9. Mass spectrometric analysis of O-linked oligosaccharides from various recombinant expression systems.

    Science.gov (United States)

    Kenny, Diarmuid T; Gaunitz, Stefan; Hayes, Catherine A; Gustafsson, Anki; Sjöblom, Magnus; Holgersson, Jan; Karlsson, Niclas G

    2013-01-01

    Analysis of O-linked glycosylation is one of the main challenges during structural validation of recombinant glycoproteins. With methods available for N-linked glycosylation in regard to oligosaccharide analysis as well as glycopeptide mapping, there are still challenges for O-linked glycan analysis. Here, we present mass spectrometric methodology for O-linked oligosaccharides released by reductive β-elimination. Using LC-MS and LC-MS(2) with graphitized carbon columns, oligosaccharides are analyzed without derivatization. This approach provides a high-throughput method for screening during clonal selection, as well as product structure verification, without impairing sequencing ability. The protocols are exemplified by analysis of glycoproteins from mammalian cell cultures (CHO cells) as well as insect cells and yeast. The data shows that the method can be successfully applied to both neutral and acidic O-linked oligosaccharides, where sialic acid, hexuronic acid, and sulfate are common substituents. Further characterization of O-glycans can be achieved using permethylation. Permethylation of O-linked oligosaccharides followed by direct infusion into the mass spectrometer provide information about oligosaccharide composition, and subsequent MS (n) experiments can be carried out to elucidate oligosaccharide structure including linkage information and sequence.

  10. Mass spectrometric analysis of the marine lipophilic biotoxins pectenotoxin-2 and okadaic acid by four different types of mass spectrometers.

    Science.gov (United States)

    Gerssen, Arjen; Mulder, Patrick; van Rhijn, Hans; de Boer, Jacob

    2008-08-01

    The performances of four different mass spectrometers [triple-quadrupole (TQ), time-of-flight (ToF), quadrupole ToF (Q-ToF) and ion trap (IT)] for the detection of the marine lipophilic toxins pectenotoxin-2 (PTX2) and okadaic acid (OA) were investigated. The spectral data obtained with the different mass spectrometric analyzers were used to propose fragmentation schemes for PTX2 in the positive electrospray mode and for OA in the negative electrospray mode. TQ data were used to obtain product ions, while ToF and Q-ToF-MS produced accurate mass data of the precursor ion and product ions, respectively. IT data provided a better understanding of the fragmentation pathways using MS(n) experiments. With respect to analytical performance, all four mass analyzers showed a good linearity (R(2) > 0.97) and repeatability (CV < 20%). Detection limits (LoDs) (S/N = 3) were the lowest on triple-quad MS: 12.2 and 2.9 pg on-column for PTX2 and OA, respectively.

  11. Mass spectrometric analysis of a UV-cross-linked protein-DNA complex: tryptophans 54 and 88 of E. coli SSB cross-link to DNA

    DEFF Research Database (Denmark)

    Steen, H; Petersen, J; Mann, M;

    2001-01-01

    . Enzymatic degradation of protein and oligonucleotide was combined with miniaturized sample preparation methods for enrichment and desalting of cross-linked peptide-nucleic acid heteroconjugates from complex mixtures prior to mass spectrometric analysis. Detailed characterization of the peptidic component...

  12. Mass spectrometric analysis of electrophoretically separated allergens and proteases in grass pollen diffusates

    Directory of Open Access Journals (Sweden)

    Geczy Carolyn L

    2003-09-01

    Full Text Available Abstract Background Pollens are important triggers for allergic asthma and seasonal rhinitis, and proteases released by major allergenic pollens can injure airway epithelial cells in vitro. Disruption of mucosal epithelial integrity by proteases released by inhaled pollens could promote allergic sensitisation. Methods Pollen diffusates from Kentucky blue grass (Poa pratensis, rye grass (Lolium perenne and Bermuda grass (Cynodon dactylon were assessed for peptidase activity using a fluorogenic substrate, as well as by gelatin zymography. Following one- or two-dimensional gel electrophoresis, Coomassie-stained individual bands/spots were excised, subjected to tryptic digestion and analysed by mass spectrometry, either MALDI reflectron TOF or microcapillary liquid chromatography MS-MS. Database searches were used to identify allergens and other plant proteins in pollen diffusates. Results All pollen diffusates tested exhibited peptidase activity. Gelatin zymography revealed high Mr proteolytic activity at ~ 95,000 in all diffusates and additional proteolytic bands in rye and Bermuda grass diffusates, which appeared to be serine proteases on the basis of inhibition studies. A proteolytic band at Mr ~ 35,000 in Bermuda grass diffusate, which corresponded to an intense band detected by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense group 1 allergen Phl p 1, was identified by mass spectrometric analysis as the group 1 allergen Cyn d 1. Two-dimensional analysis similarly demonstrated proteolytic activity corresponding to protein spots identified as Cyn d 1. Conclusion One- and two-dimensional electrophoretic separation, combined with analysis by mass spectrometry, is useful for rapid determination of the identities of pollen proteins. A component of the proteolytic activity in Bermuda grass diffusate is likely to be related to the allergen Cyn d 1.

  13. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27041659

  14. Analysis of endocrine disrupting pesticides by capillary GC with mass spectrometric detection.

    Science.gov (United States)

    Matisová, Eva; Hrouzková, Svetlana

    2012-09-01

    Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC) and fast CGC with mass spectrometric detection (MS) has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP) residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  15. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    Directory of Open Access Journals (Sweden)

    Svetlana Hrouzková

    2012-09-01

    Full Text Available Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC and fast CGC with mass spectrometric detection (MS has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  16. Mass spectrometric and high-performance liquid chromatographic studies of medroxyprogesterone acetate metabolites in human plasma.

    Science.gov (United States)

    Sturm, G; Häberlein, H; Bauer, T; Plaum, T; Stalker, D J

    1991-01-01

    Medroxyprogesterone acetate (MPA) treatment has been shown to exert several beneficial effects in cancer patients. It has been suggested that such effects are due in part to the metabolites derived from MPA in vivo. The first results are reported on the identification of 2 alpha-hydroxy- and 21-hydroxy-MPA, 20-dihydro-MPA, 17 alpha-acetoxy-2 alpha,3 beta-dihydroxy-6 alpha-methylpregn-1,4-dien-20-one and two X,21-dihydroxy-MPAs, one of them presumably being 6 alpha-hydroxymethyl-21-hydroxy-MPA, in patient's plasma by high-performance liquid chromatographic (HPLC), gas chromatographic-mass spectrometric and NMR methods. Additionally, the presence of other metabolites such as di- and tetrahydro-MPAs and 6,21-dihydroxy-MPA, found in urine and other samples, was demonstrated in plasma. For routine clinical examinations an HPLC method is described for determination of, e.g., the unreduced MPA metabolite group in Sep-Pak-ODS column extracts of patients' plasma. PMID:1827448

  17. Mass spectrometric methods for studying nutrient mineral and trace element absorption and metabolism in humans using stable isotopes: a review

    International Nuclear Information System (INIS)

    Mass spectrometric methods for determining stable isotopes of nutrient minerals and trace elements in human metabolic studies are described and discussed. The advantages and disadvantages of the techniques of electron ionization, fast atom bombardment, thermal ionization, and inductively coupled plasma and gas chromatography mass spectrometry are evaluated with reference to their accuracy, precision, sensitivity, and convenience, and the demands of human nutrition research. Examples of specific applications are described and the significance of current developments in mass spectrometry are discussed with reference to present and probable future research needs. (Author)

  18. Quantitative MALDI tandem mass spectrometric imaging of cocaine from brain tissue with a deuterated internal standard.

    Science.gov (United States)

    Pirman, David A; Reich, Richard F; Kiss, András; Heeren, Ron M A; Yost, Richard A

    2013-01-15

    Mass spectrometric imaging (MSI) is an analytical technique used to determine the distribution of individual analytes within a given sample. A wide array of analytes and samples can be investigated by MSI, including drug distribution in rats, lipid analysis from brain tissue, protein differentiation in tumors, and plant metabolite distributions. Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique capable of desorbing and ionizing a large range of compounds, and it is the most common ionization source used in MSI. MALDI mass spectrometry (MS) is generally considered to be a qualitative analytical technique because of significant ion-signal variability. Consequently, MSI is also thought to be a qualitative technique because of the quantitative limitations of MALDI coupled with the homogeneity of tissue sections inherent in an MSI experiment. Thus, conclusions based on MS images are often limited by the inability to correlate ion signal increases with actual concentration increases. Here, we report a quantitative MSI method for the analysis of cocaine (COC) from brain tissue using a deuterated internal standard (COC-d(3)) combined with wide-isolation MS/MS for analysis of the tissue extracts with scan-by-scan COC-to-COC-d(3) normalization. This resulted in significant improvements in signal reproducibility and calibration curve linearity. Quantitative results from the MSI experiments were compared with quantitative results from liquid chromatography (LC)-MS/MS results from brain tissue extracts. Two different quantitative MSI techniques (standard addition and external calibration) produced quantitative results comparable to LC-MS/MS data. Tissue extracts were also analyzed by MALDI wide-isolation MS/MS, and quantitative results were nearly identical to those from LC-MS/MS. These results clearly demonstrate the necessity for an internal standard for quantitative MSI experiments. PMID:23214490

  19. Metabolism of boldione in humans by mass spectrometric techniques: detection of pseudoendogenous metabolites.

    Science.gov (United States)

    de la Torre, Xavier; Curcio, Davide; Colamonici, Cristiana; Molaioni, Francesco; Botrè, Francesco

    2013-01-01

    Boldione is an anabolic androgenic steroid (AAS) related to boldenone, androstenedione, and testosterone bearing two double bonds in C1 and C4 positions. Boldione is rapidly transformed to the well-known AAS boldenone, being both compounds included in the list of prohibited substances and methods published yearly by the World Anti-Doping Agency (WADA). After the administration of boldione to a male volunteer, the already described urinary metabolites of boldenone produced after reduction in C4, oxydoreduction in C3 and C17, and hydroxylation have been detected. In addition, minor new metabolites have been detected and their structure postulated after mass spectrometric analyses. Finally, the reduction of the double bound in C1 produces metabolites identical to the endogenously produced ones. A method based on gas chromatography coupled to isotope ratio mass spectrometry (GC/C/IRMS) after a urine sample purification by high performance liquid chromatography (HPLC) permitted to confirm the main synthetic like boldione/boldenone metabolite (17β-hydroxy-5β-androst-1-en-3-one) and boldenone at trace levels (synthetic or endogenous origin, and to determine the exogenous origin of metabolites with the same chemical structure of the endogenous ones. The detection of pseudoendogenous androgens of synthetic origin partially overlapped boldenone and its main metabolite detection, being an additional proof of synthetic steroids misuse. By the use of IRMS, the correct evaluation of the modifications of the steroid profile after the administration of synthetic AAS that could be converted into endogenous like ones is possible. PMID:24259377

  20. Rapid Mass Spectrometric Analysis of a Novel Fucoidan, Extracted from the Brown Alga Coccophora langsdorfii

    Directory of Open Access Journals (Sweden)

    Stanislav D. Anastyuk

    2014-01-01

    Full Text Available The novel highly sulfated (35% fucoidan fraction Cf2 , which contained, along with fucose, galactose and traces of xylose and uronic acids was purified from the brown alga Coccophora langsdorfii. Its structural features were predominantly determined (in comparison with fragments of known structure by a rapid mass spectrometric investigation of the low-molecular-weight fragments, obtained by “mild” (5 mg/mL and “exhaustive” (maximal concentration autohydrolysis. Tandem matrix-assisted laser desorption/ionization mass spectra (MALDI-TOF/TOFMS of fucooligosaccharides with even degree of polymerization (DP, obtained by “mild” autohydrolysis, were the same as that observed for fucoidan from Fucus evanescens, which have a backbone of alternating (1 → 3- and (1 → 4 linked sulfated at C-2 and sometimes at C-4 of 3-linked α-L-Fucp residues. Fragmentation patterns of oligosaccharides with odd DP indicated sulfation at C-2 and at C-4 of (1 → 3 linked α-L-Fucp residues on the reducing terminus. Minor sulfation at C-3 was also suggested. The “exhaustive” autohydrolysis allowed us to observe the “mixed” oligosaccharides, built up of fucose/xylose and fucose/galactose. Xylose residues were found to occupy both the reducing and nonreducing termini of FucXyl disaccharides. Nonreducing galactose residues as part of GalFuc disaccharides were found to be linked, possibly, by 2-type of linkage to fucose residues and were found to be sulfated, most likely, at position C-2.

  1. Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples.

    Science.gov (United States)

    Hou, Xiaolin; Roos, Per

    2008-02-11

    The radiometric methods, alpha (alpha)-, beta (beta)-, gamma (gamma)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include (3)H, (14)C, (36)Cl, (41)Ca, (59,63)Ni, (89,90)Sr, (99)Tc, (129)I, (135,137)Cs, (210)Pb, (226,228)Ra, (237)Np, (241)Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed.

  2. Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples.

    Science.gov (United States)

    Hou, Xiaolin; Roos, Per

    2008-02-11

    The radiometric methods, alpha (alpha)-, beta (beta)-, gamma (gamma)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include (3)H, (14)C, (36)Cl, (41)Ca, (59,63)Ni, (89,90)Sr, (99)Tc, (129)I, (135,137)Cs, (210)Pb, (226,228)Ra, (237)Np, (241)Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed. PMID:18215644

  3. High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Burnum-Johnson, Kristin E.; Thomas, Mathew; Short, Joshua TL; Carson, James P.; Cha, Jeeyeon; Dey, Sudhansu K.; Yang, Pengxiang; Prieto Conaway, Maria C.; Laskin, Julia

    2013-10-15

    Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis (m/m=17,500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of more than 300 molecules from 92 selected m/z windows (± 1 Da) with a spatial resolution of better than 150 um. Uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pre-treatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 um/s while acquiring higher-energy collision-induced dissociation (HCD) spectra for a targeted inclusion list of 92 m/z values at a rate of ~6.3 spectra/s. Molecular ions and their corresponding fragments, separated using high-resolution mass analysis, were assigned based on accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isobaric sodium and potassium adducts of phospholipids. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules.

  4. Solid-state UV-MALDI mass spectrometric quantitation of fluroxypyr and triclopyr in soil.

    Science.gov (United States)

    Ivanova, Bojidarka; Spiteller, Michael

    2015-06-01

    The work presented here refers firstly to solid-state UV-MALDI-Orbitrap-mass spectrometric analysis of fluroxypyr (A) and triclopyr (B) in soils under laboratory conditions. The experimental design has involved the following: (a) determination of analytes A and B in polycrystalline composites of organic materials 1-7, based on 2-piperidine (pyrrolidine or piperazine)-1-yl-ethyl ammonium salts in order to determine the effect of sample preparation techniques on method performance using commercial herbicide formulations and (b) analysis of non-(X j,k,l (i) ) and sterilized (Y j,k,l (i) ) soil samples (i-fold rate 1, 10, 100, or 1,000; j-pesticide type A or B; k-time (0, 5, 10, 20, and 50 days) and l = 1-3 replicated samples) having clay content ∈ 5.0-12.0 %, silt ∈ 23.0-51.1 %, sand ∈ 7.2-72.0 %, and pH ∈ 4.0-8.1. In order to obtain a high representativeness of the data toward real-field experiments, the pollution scheme has involved 1-, 10-, 100-, and 1,000-fold rates. The firstfold rate has concentration of pollutant A of 2.639 × 10(-4) g in 625 cm(2) soil horizon of 0-25 cm(2) (5 cm depth) according to registration report (PSM-Zulassungbericht) of German Federal Office of Consumer Protection and Food Safety (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit) 6337/26.10.2009. The experimental design has involved quincunx systematic statistical approach for collection of soil samples. The performance has been compared with the corresponding statistical variable obtained, using an independent HPLC-ESI-(APCI-)-MS/MS analysis. PMID:25555463

  5. Lipopeptides from the Banyan Endophyte, Bacillus subtilis K1: Mass Spectrometric Characterization of a Library of Fengycins

    Science.gov (United States)

    Pathak, Khyati V.; Keharia, Haresh; Gupta, Kallol; Thakur, Suman S.; Balaram, Padmanabhan

    2012-10-01

    Mass spectrometric analysis of a banyan endophyte, Bacillus subtilis K1, extract showing broad spectrum antifungal activity revealed a complex mixture of lipopeptides, iturins, surfactins, and fengycins. Fractionation by reversed-phase high performance liquid chromatography (HPLC) facilitated a detailed analysis of fengycin microheterogeneity. Matrix assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometric studies permitted the identification of several new fengycin variants. Four major sites of heterogeneity are identified: (1) N-terminus β-hydroxy fatty acid moiety, where chain length variation and the presence of unsaturation occur, (2) position 6 (Ala/Val/Ile/Leu), (3) position 10 (Val/Ile) within the macrocyclic ring, and (4) Gln to Glu replacement at position 8, resulting in fengycin variants that differ in mass by 1 Da. Diagnostic fragment ions provide a quick method for localizing the sites of variation in the macrocycle or the linear segment. Subsequent establishment of the sequences is achieved by MS/MS analysis of linear fengycin species produced by hydrolysis of the macrocyclic lactone. Unsaturation in the fatty acid chain and the presence of linear precursors in the B. subtilis K1 extract are also established by mass spectrometry. The anomalous distribution of intensities within isotopic multiplets is a diagnostic for Gln/Glu replacements. High resolution mass spectrometry facilitates the identification of fengycin species differing by 1 Da by localizing the variable position (Gln8/Glu8) in the fengycin variants.

  6. Activity-Based Costing Application in an Urban Mass Transport Company

    Directory of Open Access Journals (Sweden)

    Popesko Boris

    2011-12-01

    Full Text Available The purpose of this paper is to provide a basic overview of the application of Activity-Based Costing in an urban mass transport company which operates land public transport via buses and trolleys within the city. The case study was conducted using the Activity-Based Methodology in order to calculate the true cost of individual operations and to measure the profitability of particular transport lines. The case study analysis showed the possible effects of the application of the Activity-Based Costing for an urban mass transport company as well as the limitations of using the ABC methodology in the service industry. With regards to the application of the ABC methodology, the primary limitation of the accuracy of the conclusions is the quality of the non-financial information which had to be gathered throughout the implementation process. A basic limitation of the accurate data acquisition is the nature of the fare system of the transport company which does not allow the identification of the route that is taken by an individual passenger. The study illustrates the technique of ABC in urban mass transport and provides a real company example of information outputs of the ABC system. The users indicated that, the ABC model is very useful for profitability reporting and profit management. Also, the paper shows specific application of the Activity-Based Methodology in conditions of urban mass transport companies with regional specifics.

  7. Desorption Electrospray Ionization (DESI) Mass Spectrometric Imaging of the Distribution of Rohitukine in the Seedling of Dysoxylum binectariferum Hook. F.

    Science.gov (United States)

    Mohana Kumara, Patel; Srimany, Amitava; Arunan, Suganya; Ravikanth, Gudasalamani; Uma Shaanker, Ramanan; Pradeep, Thalappil

    2016-01-01

    Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae) was performed to reconstruct the molecular distribution of rohitukine (Rh) and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. Desorption electrospray ionization mass spectrometry imaging (DESI MSI) and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) analysis detected Rh as well as its glycosylated, acetylated, oxidized, and methoxylated analogues. Rh was predominantly distributed in the main roots, collar region of the stem, and young leaves. In the stem and roots, Rh was primarily restricted to the cortex region. The identities of the metabolites were assigned based on both the fragmentation patterns and exact mass analyses. We discuss these results, with specific reference to the possible pathways of Rh biosynthesis and translocation during seedling development in D. binectariferum. PMID:27362422

  8. Desorption Electrospray Ionization (DESI Mass Spectrometric Imaging of the Distribution of Rohitukine in the Seedling of Dysoxylum binectariferum Hook. F.

    Directory of Open Access Journals (Sweden)

    Patel Mohana Kumara

    Full Text Available Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae was performed to reconstruct the molecular distribution of rohitukine (Rh and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. Desorption electrospray ionization mass spectrometry imaging (DESI MSI and electrospray ionization (ESI tandem mass spectrometry (MS/MS analysis detected Rh as well as its glycosylated, acetylated, oxidized, and methoxylated analogues. Rh was predominantly distributed in the main roots, collar region of the stem, and young leaves. In the stem and roots, Rh was primarily restricted to the cortex region. The identities of the metabolites were assigned based on both the fragmentation patterns and exact mass analyses. We discuss these results, with specific reference to the possible pathways of Rh biosynthesis and translocation during seedling development in D. binectariferum.

  9. High-Performance Liquid Chromatographic-Tandem Mass Spectrometric Determination of Itraconazole in Human Plasma for Bioavailability and Bioequivalence Studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Wook; Nam, Dae Young; Kang, Kyoung Hoon; Ha, Kyung Wook; Han, In Hee; Chang, Byung Kon; Yoon, Mi Kyeong; Lee, Jae Hwi [Chung-Ang University, Seoul (Korea, Republic of)

    2006-02-15

    A highly sensitive high-performance liquid chromatographic-tandem mass spectrometric method (HPLC-MSMS) has been developed to quantify itraconazole in human plasma for the purpose of pharmacokinetic studies. Sample preparation was carried out by liquid-liquid extraction using loratadine as an internal standard. Chromatographic separation used a YMC C{sub 18} column, giving an extremely fast total run time of 3 min. The method was validated and used for the bioequivalence study of itraconazole tablets in healthy male volunteers (n = 31). The lower limit of detection proved to be 0.2 ng /mL for itraconazole.

  10. Mass spectrometric analysis of laser evaporation products of ceramics of Bi2Sr2CaCu2Ox composition

    International Nuclear Information System (INIS)

    Mass spectrometric analysis is used to study mechanism of laser evaporation of superconducting ceramics of Bi2Sr2CaCu2Ox composition. During evaporation as a result of pulsed laser irradiation of a sample placed in vaccum ions of all metals containing in ceramics and also neutral O2, Ca, Sr, Cu, Bi and metal oxides were detected on yttrium aluminate. Time-of-flight spectra had two peaks corresponding to ion and neutral components. Comparison of neutral components. Comparison of neutral particle rates points to the fact that gas dynamic processes connected with formation of dense gas cloud near the target surface play an important

  11. Development of a combined chemical and enzymatic approach for the mass spectrometric identification and quantification of aberrant N-glycosylation.

    Science.gov (United States)

    Chen, Rui; Wang, Fangjun; Tan, Yexiong; Sun, Zhen; Song, Chunxia; Ye, Mingliang; Wang, Hongyang; Zou, Hanfa

    2012-02-16

    Direct mass spectrometric analysis of aberrant protein glycosylation is a challenge to the current analytical techniques. Except lectin affinity chromatography, no other glycosylation enrichment techniques are available for analysis of aberrant glycosylation. In this study, we developed a combined chemical and enzymatic strategy as an alternative for the mass spectrometric analysis of aberrant glycosylation. Sialylated glycopeptides were enriched with reverse glycoblotting, cleaved by endoglycosidase F3 and analyzed by mass spectrometry with both neutral loss triggered MS(3) in collision induced dissociation (CID) and electron transfer dissociation (ETD). Interestingly, a great part of resulted glycopeptides were found with fucose attached to the N-acetylglucosamine (N-GlcNAc), which indicated that the aberrant glycosylation that is carrying both terminal sialylation and core fucosylation was identified. Totally, 69 aberrant N-glycosylation sites were identified in sera samples from hepatocellular carcinoma (HCC) patients. Following the identification, quantification of the level of this aberrant glycosylation was also carried out using stable isotope dimethyl labeling and pooled sera sample from liver cirrhosis and HCC was compared. Six glycosylation sites demonstrated elevated level of aberrancy, which demonstrated that our developed strategy was effective in both qualitative and quantitative studies of aberrant glycosylation. PMID:22202184

  12. Mass spectrometric protein characterization in proteome analysis using GELoader tip micro-columns packed with various chromatographic material

    International Nuclear Information System (INIS)

    In the early 90'ies mass spectrometry (MS) was introduced as a tool for identifying proteins in protein sequence databases. Since then it has become an integrated tool in protein characterization and is today routinely used to identify proteins separated by gel electrophoresis. A two-tiered mass spectrometric protein identification strategy has recently been proposed. In the first strategy peptide mass maps obtained from the protein of interest are compared with theoretically derived peptide mass maps from proteins in protein sequence databases. If the protein cannot be identified by this strategy, tandem mass spectrometric sequencing is used to generate enough sequence data to identify the protein in protein sequence databases or expressed sequence tag (EST) databases. However, the above strategies primarily identify a protein relatively to the DNA sequence, in which no information about e.g. post-translational modifications (PTMs) is stored. PTMs are known to modify the function, location, solubility and activity of proteins in the cell, and they are therefore very important for understanding living cells. More than 200 different PTMs are known, of which glycosylation, phosphorylation and proteolytic processing are the most common ones. Mass spectrometric analysis of PTMs on gel-separated proteins requires a higher amount of protein than for identification only. In addition, higher sequence coverage from the peptide mass maps or pre-purification of the modified peptides prior to MS analysis, is necessary for detection of putative modified peptides. In this study a multi-tiered strategy, in which GELoader tip micro-columns packed with increasingly more hydrophobic chromatographic material are used in combination with mass spectrometry, is described. The ultimate aim was to gain increased sequence coverage from peptide mixtures derived from gel-separated proteins, in order to locate modified peptides. Graphite powder is described as an alternative to traditional

  13. Comparative mass spectrometric analyses of Photofrin oligomers by fast atom bombardment mass spectrometry, UV and IR matrix-assisted laser desorption/ionization mass spectrometry, electrospray ionization mass spectrometry and laser desorption/jet-cooling photoionization mass spectrometry.

    Science.gov (United States)

    Siegel, M M; Tabei, K; Tsao, R; Pastel, M J; Pandey, R K; Berkenkamp, S; Hillenkamp, F; de Vries, M S

    1999-06-01

    Photofrin (porfimer sodium) is a porphyrin derivative used in the treatment of a variety of cancers by photodynamic therapy. This oligomer complex and a variety of porphyrin monomers, dimers and trimers were analyzed with five different mass spectral ionization techniques: fast atom bombardment, UV and IR matrix-assisted laser desorption/ionization, electrospray ionization, and laser desorption/jet-cooling photoionization. All five approaches resulted in very similar oligomer distributions with an average oligomer length of 2.7 +/- 0.1 porphyrin units. In addition to the Photofrin analysis, this study provides a side-by-side comparison of the spectra for the five different mass spectrometric techniques.

  14. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography 64 to 70 Moisture by the Coulomet...

  15. Mass distributions of a macromolecular assembly based on electrospray ionization mass spectrometric masses of the constituent subunits

    Indian Academy of Sciences (India)

    Leonid Hanin; Brian Green; Franck Zal; Serge Vinogradov

    2003-09-01

    Macromolecular assemblies containing multiple protein subunits and having masses in the megadalton (MDa) range are involved in most of the functions of a living cell. Because of variation in the number and masses of subunits, macromolecular assemblies do not have a unique mass, but rather a mass distribution. The giant extracelular erythrocruorins (Ers), ∼ 3.5 MDa, comprized of at least 180 polypeptide chains, are one of the best characterized assemblies. Three-dimensional reconstructions from cryoelectron microscopic images show them to be hexagonal bilayer complexes of 12 subassemblies, each comprised of 12 globin chains, anchored to a subassembly of 36 nonglobin linker chains. We have calculated the most probable mass distributions for Lumbricus and Riftia assemblies and their globin and linker subassemblies, based on the Lumbricus Er stoichiometry and using accurate subunit masses obtained by electrospray ionization mass spectrometry. The expected masses of Lumbricus and Riftia Ers are 3.517 MDa and 3.284 MDa, respectively, with a possible variation of ∼ 9% due to the breadth of the mass distributions. The Lumbricus Er mass is in astonishingly good agreement with the mean of 23 known masses, 3.524 ± 0.481 MDa.

  16. Gas chromatographic-mass spectrometric analysis of steroids and steroid glucuronides in the seminal vesicle fluid of the African catfish, Clarias gariepinus

    NARCIS (Netherlands)

    Schoonen, W.G.E.J.; Lambert, J.G.D.

    1987-01-01

    Gas chromatographic-mass spectrometric analysis was carried out to identify steroids and steroid glucuronides in the seminal vesicle fluid of African catfish, Clarias gariepinus, collected in the Hula nature reserve (Israel) during the breeding season. Full mass spectra of 5β-pregnane-3α,17α-diol-20

  17. Applications of information theory and pattern recognition to gas chromatography-mass spectrometric analysis of toxic organic compounds in ambient air

    Energy Technology Data Exchange (ETDEWEB)

    Scott, D.R.

    1986-05-01

    The number of information channels contained in the gas-chromatographic, mass-spectrometric, and combined gas chromatography-mass spectrometric analysis of 78 toxic organic compounds was determined. The toxic compounds are those routinely monitored in ambient air samples using Tenax collection and gas chromatography-mass spectrometric analysis. The Shannon information content of the binary encoded and full-intensity mass spectra, of the gas-chromatographic retention times, and of the combined gas chromatographic-mass spectrometric spectra of the 78 compounds was calculated. The maximum binary information contents of the 35 channel gas chromatographic, 17 key channel mass spectral, and the 595 channel gas chromatographic-mass spectral methods were 6.4, 15.4, and < 21.8 bits, respectively. The 17 masses with the highest binary information content with regard to the 78 compounds were used with SIMCA pattern recognition to determine four classes among the 78 compounds. These included aromatics without chlorine substitution, chloroaromatics, bromoalkanes and alkenes, and chloroalkanes and alkenes.

  18. A gas/liquid chromatographic-mass spectrometric method for the rapid screening of 250 pesticides in aqueous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Chandramouli, B.; Harvan, D.; Brittain, S.; Hass, R. [Eno River Labs, LLC. Durham, NC (United States)

    2004-09-15

    Pesticide residues in food present a potentially serious and significant cause for concern. Many pesticides have been associated with significant health effects to the nervous and endocrine systems and some have been deemed carcinogenic. There are many well-established techniques for pesticide analysis. However, commercial pesticide methods have traditionally only been available for specific pesticide families, such as chlorinated pesticides or herbicides, and at detection limits ranging from 0.05 ppb to 1 ppm in aqueous matrices. Techniques that can quickly screen for the presence/absence of pesticide residues in food matrices are critical in ensuring the safety of food and water. This paper outlines a combined Gas Chromatographic-High Resolution Mass Spectrometric (GC-HRMS) and Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) screening assay for 250 pesticides that was developed for use in water, and soda samples at screening levels ranging from 0.1-5 ppb. The pesticides selected have been identified by the European Union as being of concern and the target of possible legislation. The list encompasses a variety of pesticide classes and compound groupings.

  19. Spectrometric techniques 4

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume IV discusses three widely diversified areas of spectrometric techniques. The book focuses on three spectrometric methods. Chapter 1 discusses the phenomenology and applications of Coherent Anti-Stokes Raman Spectroscopy (CARS), the most commonly used optical technique that exploit the Raman effect. The second chapter is concerned with diffraction gratings and mountings for the Vacuum Ultraviolet Spectral Region. Chapter 3 accounts the uses of mass spectrometry, detectors, types of spectrometers, and ion sources. Physicists and chemists will find the book a go

  20. The mechanism of 2-furaldehyde formation from D-xylose dehydration in the gas phase. A tandem mass spectrometric study.

    Science.gov (United States)

    Ricci, Andreina; Piccolella, Simona; Pepi, Federico; Garzoli, Stefania; Giacomello, Pierluigi

    2013-07-01

    The mechanism of reactions occurring in solution can be investigated also in the gas phase by suited mass spectrometric techniques, which allow to highlight fundamental mechanistic features independent of the influence of the medium and to clarifying controversial hypotheses proposed in solution studies. In this work, we report a gas-phase study performed by electrospray triple stage quadrupole mass spectrometry (ESI-TSQ/MS) on the dehydration of D-xylose, leading mainly to the formation of 2-furaldehyde (2-FA). It is generally known in carbohydrate chemistry that the thermal acid catalyzed dehydration of pentoses leads to the formation of 2-FA, but several aspects on the solution-phase mechanism are controversial. Here, gaseous reactant ions corresponding to protonated xylose molecules obtained from ESI of a solution containing D-xylose and ammonium acetate as protonating reagent were allowed to undergo collisionally activated decomposition (CAD) into the triple stage quadrupole analyzer. The product ion mass spectra of protonated xylose are characterized by the presence of ionic intermediates arising from xylose dehydration, which were structurally characterized by their fragmentation patterns. As expected, the xylose triple dehydration leads to the formation of the ion at m/z 97, corresponding to protonated 2-FA. On the basis of mass spectrometric evidences, we demonstrated that in the gas phase, the formation of 2-FA involves protonation at the OH group bound to the C1 atom of the sugar, the first ionic intermediate being characterized by a cyclic structure. Finally, energy resolved product ion mass spectra allowed to obtain information on the energetic features of the D-xylose→2-FA conversion. ᅟ PMID:23690250

  1. In Situ Probing of Cholesterol in Astrocytes at the Single Cell Level using Laser Desorption Ionization Mass Spectrometric Imaging with Colloidal Silver

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, D.C.; Cha, Sangwon; Oh, Jisun; Sakaguchi, Donald S.; Yeung, Edward S.; and Lee, Young Jin

    2010-03-18

    Mass spectrometric imaging has been utilized to localize individual astrocytes and to obtain cholesterol populations at the single-cell level in laser desorption ionization (LDI) with colloidal silver. The silver ion adduct of membrane-bound cholesterol was monitored to detect individual cells. Good correlation between mass spectrometric and optical images at different cell densities indicates the ability to perform single-cell studies of cholesterol abundance. The feasibility of quantification is confirmed by the agreement between the LDI-MS ion signals and the results from a traditional enzymatic fluorometric assay. We propose that this approach could be an effective tool to study chemical populations at the cellular level.

  2. 2DB: a Proteomics database for storage, analysis, presentation, and retrieval of information from mass spectrometric experiments

    Directory of Open Access Journals (Sweden)

    Hippler Michael

    2008-07-01

    Full Text Available Abstract Background The amount of information stemming from proteomics experiments involving (multi dimensional separation techniques, mass spectrometric analysis, and computational analysis is ever-increasing. Data from such an experimental workflow needs to be captured, related and analyzed. Biological experiments within this scope produce heterogenic data ranging from pictures of one or two-dimensional protein maps and spectra recorded by tandem mass spectrometry to text-based identifications made by algorithms which analyze these spectra. Additionally, peptide and corresponding protein information needs to be displayed. Results In order to handle the large amount of data from computational processing of mass spectrometric experiments, automatic import scripts are available and the necessity for manual input to the database has been minimized. Information is in a generic format which abstracts from specific software tools typically used in such an experimental workflow. The software is therefore capable of storing and cross analysing results from many algorithms. A novel feature and a focus of this database is to facilitate protein identification by using peptides identified from mass spectrometry and link this information directly to respective protein maps. Additionally, our application employs spectral counting for quantitative presentation of the data. All information can be linked to hot spots on images to place the results into an experimental context. A summary of identified proteins, containing all relevant information per hot spot, is automatically generated, usually upon either a change in the underlying protein models or due to newly imported identifications. The supporting information for this report can be accessed in multiple ways using the user interface provided by the application. Conclusion We present a proteomics database which aims to greatly reduce evaluation time of results from mass spectrometric experiments and enhance

  3. Ultraviolet irradiation-induced substitution of fluorine with hydroxyl radical for mass spectrometric analysis of perfluorooctane sulfonyl fluoride.

    Science.gov (United States)

    Wang, Peng; Tang, Xuemei; Huang, Lulu; Kang, Jie; Zhong, Hongying

    2016-01-28

    A rapid and solvent free substitution reaction of a fluorine atom in perfluorooctane sulfonyl fluoride (PFOSF) with a hydroxyl radical is reported. Under irradiation of ultraviolet laser on semiconductor nanoparticles or metal surfaces, hydroxyl radicals can be generated through hole oxidization. Among all fluorine atoms of PFOSF, highly active hydroxyl radicals specifically substitute the fluorine of sulfonyl fluoride functional group. Resultant perfluorooctane sulfonic acid is further ionized through capture of photo-generated electrons that switch the neutral molecules to negatively charged odd electron hypervalent ions. The unpaired electron subsequently initiates α O-H bond cleavage and produces perfluorooctane sulfonate negative ions. Hydroxyl radical substitution and molecular dissociation of PFOSF have been confirmed by masses with high accuracy and resolution. It has been applied to direct mass spectrometric imaging of PFOSF adsorbed on surfaces of plant leaves.

  4. Thermodynamic properties of the UO2-ZrO2 system studied by the isothermal mass spectrometric vaporization method

    International Nuclear Information System (INIS)

    The Knudsen effusion high-temperature mass spectrometric method was used to study the vaporization processes and thermodynamic properties of the UO2-ZrO2 system in the temperature range 2200-2650 K. The work was carried out with the MS 1301 mass spectrometer developed for studies of physico-chemical properties of inorganic substances at high temperatures. Vaporization of the solid solutions containing 0.02-0.45 mol fractions of UO2 was done using tungsten cells. The vaporization processes and the chemical potentials of ZrO2 in the UO2-ZrO2 system and in the Y2O3-ZrO2, Lu2O3-ZrO2 and HfO2-ZrO2 systems, available in the literature, were discussed from the point of view of the acid-base concept. (orig.)

  5. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    Science.gov (United States)

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-11-10

    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria.

  6. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

  7. Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

    International Nuclear Information System (INIS)

    D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitative these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra. (orig.)

  8. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  9. Differentiation of the four major types (C. Burmannii, C. Verum, C. cassia, And C. Loureiroi) of cinnamons using a flow-injection mass spectrometric (FIMS) fingerprinting method

    Science.gov (United States)

    A simple and efficient flow-injection mass spectrometric (FIMS) method was developed to differentiate cinnamon (Cinnamomum) bark (CB) samples of the four major species (C. burmannii, C. verum, C. aromaticum, and C. loureiroi) of cinnamon. Fifty cinnamon samples collected from China, Vietnam, Indon...

  10. Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection

    DEFF Research Database (Denmark)

    Justesen, U.; Knuthsen, Pia; Leth, Torben

    1998-01-01

    A high-performance liquid chromatographic (HPLC) separation method viith photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained...

  11. Standard methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium metal

    International Nuclear Information System (INIS)

    Methods are described for the analysis of matrix materials and various impurities in Pu metal. Controlled-potential coulometry, amperometric titration with Fe2+, or titration with ceric sulfate methods are described for the determination of Pu. A mass spectrometric method is given for determination of the isotopic content of the metal. Determination of C by direct combustion-thermal conductivity is described. Methods for the spectrophotometric determination of U with arsenazo I, Th with thorin, Fe with 1,10-phenanthroline or α,α'-dipyridyl, and Cl-, F-, N, and S following separation by distillation are described. If the Pu metal does not contain significant amounts of other radioactive fission products or high specific-activity γ emitters, 241Am may be determined by γ counting. Determination of γ-emitting fission products, U and Th, is determined by γ spectroscopy. Spectrochemical methods for the determination of rare earths, W, Nb, Ta, and about 40 other trace elements are included

  12. Mass spectrometric detection of proteins in non-aqueous media : the case of prion proteins in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Douma, M.D.; Kerr, G.M.; Brown, R.S.; Keller, B.O.; Oleschuk, R.D. [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

    2008-08-15

    This paper presented a filtration method for detecting protein traces in non-aqueous media. The extraction technique used a mixture of acetonitrile, non-ionic detergent and water along with filter disks with embedded C{sub 8}-modified silica particles to capture the proteins from non-aqueous samples. The extraction process was then followed by an elution of the protein from the filter disk and direct mass spectrometric detection and tryptic digestion with peptide mapping and MS/MS fragmentation of protein-specific peptides. The method was used to detect prion proteins in spiked biodiesel samples. A tryptic peptide with the sequence YGQGSPGGNR was used for unambiguous identification. Results of the study showed that the method is suitable for the large-scale testing of protein impurities in tallow-based biodiesel production processes. 33 refs., 6 figs.

  13. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

  14. Stable isotope dilution analysis of salicylic acid and hydroquinone in human skin samples by gas chromatography with mass spectrometric detection.

    Science.gov (United States)

    Judefeind, Anja; van Rensburg, Peet Jansen; Langelaar, Stephan; du Plessis, Jeanetta

    2007-06-01

    A sensitive and accurate gas chromatographic-mass spectrometric (GC-MS) method has been developed for the quantitative determination of salicylic acid (SA) and hydroquinone (HQ) from human skin samples and cosmetic emulsions. Deuterium labeled SA-d(6) and HQ-d(6) were used as internal standards (IS). The samples were extracted with methanol, dried under nitrogen and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS). Quantification was performed in SIM mode with a limit of quantification (LOQ) of 50 ng ml(-1) for SA and 10 ng ml(-1) for HQ. The inter-day variation (R.S.D.) was less than 5% and the accuracy was better than 13.3% for both compounds. The recoveries from the different matrices ranged between 93.1 and 103.3% for SA, and 97.3 and 100.8% for HQ.

  15. A microchip electrophoresis-mass spectrometric platform with double cell lysis nano-electrodes for automated single cell analysis.

    Science.gov (United States)

    Li, Xiangtang; Zhao, Shulin; Hu, Hankun; Liu, Yi-Ming

    2016-06-17

    Capillary electrophoresis-based single cell analysis has become an essential approach in researches at the cellular level. However, automation of single cell analysis has been a challenge due to the difficulty to control the number of cells injected and the irreproducibility associated with cell aggregation. Herein we report the development of a new microfluidic platform deploying the double nano-electrode cell lysis technique for automated analysis of single cells with mass spectrometric detection. The proposed microfluidic chip features integration of a cell-sized high voltage zone for quick single cell lysis, a microfluidic channel for electrophoretic separation, and a nanoelectrospray emitter for ionization in MS detection. Built upon this platform, a microchip electrophoresis-mass spectrometric method (MCE-MS) has been developed for automated single cell analysis. In the method, cell introduction, cell lysis, and MCE-MS separation are computer controlled and integrated as a cycle into consecutive assays. Analysis of large numbers of individual PC-12 neuronal cells (both intact and exposed to 25mM KCl) was carried out to determine intracellular levels of dopamine (DA) and glutamic acid (Glu). It was found that DA content in PC-12 cells was higher than Glu content, and both varied from cell to cell. The ratio of intracellular DA to Glu was 4.20±0.8 (n=150). Interestingly, the ratio drastically decreased to 0.38±0.20 (n=150) after the cells are exposed to 25mM KCl for 8min, suggesting the cells released DA promptly and heavily while they released Glu at a much slower pace in response to KCl-induced depolarization. These results indicate that the proposed MCE-MS analytical platform may have a great potential in researches at the cellular level. PMID:27207575

  16. Novel concepts and strategies in anticancer metallodrug development : towards oral activity, peptide conjugation and mass spectrometric applications

    International Nuclear Information System (INIS)

    including top-down electrospray ionization-mass spectrometry (ESI-MS). Mass spectrometry is an invaluable tool in the analysis of molecular interactions between metallodrugs and biomolecules, such as DNA or proteins and their constituents. Furthermore, the molecular reactivity may give insight into the mode of action of a particular metallodrug or family of metallodrugs. Within the frame of this Ph.D. thesis, mass spectrometric techniques have been used to characterize the reactivity of representative (thio)pyr(id)onato RuII–p-cymene metallodrugs towards amino acids, nucleotides and proteins and an inverse correlation was found between extent of protein binding and antiproliferative activity, at least for these families of metallodrugs. Furthermore, the analysis of metallation sites of metallodrugs on proteins by mass spectrometric methods poses significant challenges in many cases due to low adduct detection efficiencies. Top-down mass spectrometric analysis is a promising approach to determine oxaliplatin binding sites on ubiquitin and different fragmentation techniques were investigated with the combination of higher energy C-trap dissociation (HCD) and electron transfer dissociation (ETD) tandem mass spectrometry yielding the highest information content. This approach led to the confirmation of methionine-1 as the primary and histidine-68 as the secondary binding site. (author)

  17. Mass Spectrometric Fragmentation of 1-(Benzyloxycarbonyl)amino-2-alkyl/cycloalkyl Thioacetates: a Thioester Pyrolysis-type Rearrangement under Electron Impact Ionization

    Institute of Scientific and Technical Information of China (English)

    Shu XU; Jia Xi XU

    2006-01-01

    The mass spectrometric fragmentation of 1-(benzyloxycarbonyl)amino-2-alkyl/cycloalkyl thioacetates has been studied with the aid of mass-analysed ion kinetic energy spectrometry under electron impact ionization. All compounds show a tendency to eliminate a ketene, thioacetic acid, and benzyl carbamate molecule, or an acetyl and benzyloxy radicals. A thioester pyrolysis-type rearrangement under electron impact ionizations was observed.

  18. Partial vapor-phase hydrolysis of peptide bonds: A method for mass spectrometric determination of O-glycosylated sites in glycopeptides

    DEFF Research Database (Denmark)

    Mirgorodskaya, E; Hassan, H; Wandall, H H;

    1999-01-01

    In this study we present a method for determination of O-glycosylation sites in glycopeptides, based on partial vapor-phase acid hydrolysis in combination with mass spectrometric analysis. Pentafluoropropionic acid and hydrochloric acid were used for the hydrolysis of glycosylated peptides. The r...... of the reaction products without further purification both by matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry....

  19. Application of mass spectrometric techniques for the trace analysis of short-lived iodine-containing volatiles emitted by seaweed.

    Science.gov (United States)

    Kundel, Michael; Thorenz, Ute R; Petersen, Jan H; Huang, Ru-Jin; Bings, Nicolas H; Hoffmann, Thorsten

    2012-04-01

    Knowledge of the composition and emission rates of iodine-containing volatiles from major widespread seaweed species is important for modeling the impact of halogens on gas-phase atmospheric chemistry, new particle formation, and climate. In this work, we present the application of mass spectrometric techniques for the quantification of short-lived iodine-containing volatiles emitted by eight different seaweeds from the intertidal zone of Helgoland, Germany. A previously developed online time-of-flight aerosol mass spectrometric method was used to determine I(2) emission rates and investigate temporally resolved emission profiles. Simultaneously, iodocarbons were preconcentrated on solid adsorbent tubes and quantified offline using thermodesorption-gas chromatography-mass spectrometry. The total iodine content of the seaweeds was determined using microwave-assisted tetramethylammonium hydroxide extraction followed by inductively coupled-plasma mass spectrometry analysis. The highest total iodine content was found in the Laminariales, followed by the brown algae Ascophyllum nodosum, Fucus vesiculosus, Fucus serratus, and both red algae Chondrus crispus and Delesseria sanguinea. Laminariales were found to be the strongest I(2) emitters. Time series of the iodine release of Laminaria digitata and Laminaria hyperborea showed a strong initial I(2) emission when first exposed to air followed by an exponential decline of the release rate. For both species, I(2) emission bursts were observed. For Laminaria saccharina und F. serratus, a more continuous I(2) release profile was detected, however, F. serratus released much less I(2). A. nodosum and F. vesiculosus showed a completely different emission behavior. The I(2) emission rates of these species were slowly increasing with time during the first 1 to 2 h until a more or less stable I(2) emission rate was reached. The lowest I(2) emission rates were detected for the red algae C. crispus and D. sanguinea. Total iodocarbon

  20. Product Identification and Mass Spectrometric Analysis of n-Butane and i-Butane Pyrolysis at Low Pressure

    Institute of Scientific and Technical Information of China (English)

    Yi-jun Zhang; Wen-hao Yuan; Jiang-huai Cai; Li-dong Zhang; Fei Qi; Yu-yang Li

    2013-01-01

    The pyrolysis of n-butane andi-butane at low pressure was investigated from 823-1823 K in an electrically heated flow reactor using synchrotron vacuum ultraviolet photoionization mass spectrometry.More than 20 species,especially several radicals and isomers,were detected and identified from the measurements of photoionization efficiency (PIE) spectra.Based on the mass spectrometric analysis,the characteristics of n-butane and i-butane pyrolysis were discussed,which provided experimental evidences for the discussion of decomposition pathways of butane isomers.It is concluded that the isomeric structures of n-butane and i-butane have strong influence on their main decomposition pathways,and lead to dramatic differences in their mass spectra and PIE spectra such as the different dominant products and isomeric structures of butene products.Furthermore,compared with n-butane,i-butane can produce strong signals of benzene at low temperature in its pyrolysis due to the enhanced formation of benzene precursors like propargyl and C4 species,which provides experimental clues to explain the higher sooting tendencies of iso-alkanes than n-alkanes.

  1. Metallomics investigations on potential binding partners of methylmercury in tuna fish muscle tissue using complementary mass spectrometric techniques.

    Science.gov (United States)

    Kutscher, Daniel J; Sanz-Medel, Alfredo; Bettmer, Jörg

    2012-08-01

    In this study, the binding behaviour of methylmercury (MeHg(+)) towards proteins is investigated. Free sulfhydryl groups in cysteine residues are known to be the most likely binding partners, due to the high affinity of mercury to sulphur. However, detailed knowledge about discrete binding sites in living organisms has been so far scarce. A metallomics approach using different methods like size-exclusion chromatography (SEC) and liquid chromatography (LC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) as well as complementary mass spectrometric techniques (electrospray ionisation-tandem mass spectrometry, ESI-MS/MS) are combined to sequence and identify possible target proteins or peptides after enzymatic digestion. Potential targets for MeHg(+) in tuna fish muscle tissue are investigated using the certified reference material CRM464 as a model tissue. Different extraction procedures appropriate for the extraction of proteins are evaluated for their efficiency using isotope dilution analysis for the determination of total Hg in the extracts. Due to the high chemical stability of the mercury-sulphur bond, the bioconjugate can be quantitatively extracted with a combination of tris(hydroxymethyl)aminomethane (TRIS) and sodium dodecyl sulphate (SDS). Using different separation techniques such as SEC and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) it can be shown that major binding occurs to a high-molecular weight protein (M(w) > 200 kDa). A potential target protein, skeletal muscle myosin heavy chain, could be identified after tryptic digestion and capillary LC-ESI-MS/MS.

  2. A review of recent advances in mass spectrometric methods for gas-phase chiral analysis of pharmaceutical and biological compounds.

    Science.gov (United States)

    Wu, Lianming; Vogt, Frederick G

    2012-10-01

    Chirality has been of great interest in pharmaceutical and biological sciences. The capabilities of mass spectrometry (MS) for rapid analysis of complex mixtures have encouraged its exploration for gas-phase chiral differentiation. Although particular instances of successful discrimination between enantiomers have been reported over the past three decades, a general method of quantitative chiral analysis by MS has only been demonstrated recently. This review describes the current state of the chiral MS methods without chiral chromatographic separation, which fall into five main categories: (1) the kinetic method, (2) host-guest (H-G) diastereomeric adduct formation, (3) ion/molecule (equilibrium) reactions, (4) collision-induced dissociation (CID) of diastereomeric adducts, and (5) the emerging technique for gas-phase separation using ion mobility spectrometry (IMS). It emphasizes tandem mass spectrometry (MS/MS), which provides several unique analytical advantages for quantitative chiral analysis. These include intrinsically high sensitivity, molecular specificity, and tolerance to impurities as well as the simplicity and speed of the mass spectrometric measurements. Practical prospects and current challenges in quantitative chiral MS techniques for QbD (quality-by-design)-based pharmaceutical applications are also discussed. PMID:22579598

  3. Terverticillate penicillia studied by direct electrospray mass spectrometric profiling of crude extracts II. Database and identification

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn

    1997-01-01

    A mass spectral database was built using standard instrument software from 678 electrospray mass spectra (mass profiles) from crude fungal extracts of terverticillate taxa within the genus Penicillium. The match factors calculated from searching all the mass profiles stored in the database were...... isolates stored according to classical taxonomic criteria. Mass profiles collected in previous studies could be identified by a search in the database. (C) 1997 Elsevier Science Ltd....

  4. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator andarine (S-4) for routine doping control purposes.

    Science.gov (United States)

    Thevis, Mario; Thomas, Andreas; Fusshöller, Gregor; Beuck, Simon; Geyer, Hans; Schänzer, Wilhelm

    2010-08-15

    Selective androgen receptor modulators (SARMs) are potent anabolic agents with tissue-selective properties. Due to their potential misuse in elite sport, the World Anti-Doping Agency (WADA) has prohibited SARMs since 2008, and although no representative drug candidate has yet received full clinical approval, recent findings of SARMs illegally sold via the internet have further supported the need to efficiently test for these compounds in doping controls. In the present communication, the mass spectrometric characterization of urinary metabolites of the SARM Andarine (also referred to as S-4) compared with earlier in vitro and animal studies is reported. Liquid chromatography interfaced to high-resolution/high-accuracy (tandem) mass spectrometry was used to identify phase I and II metabolites, confirming the predicted target analytes for sports drug testing purposes including the glucuronic acid conjugates of the active drug, its monohydroxylated and/or deacetylated product, the hydrolysis product resulting from the removal of the compound's B-ring, as well as the sulfate of the monohydroxylated and the deacetylated phase I metabolite. The obtained data will support future efforts to effectively screen for and confirm the misuse of the non-approved drug candidate Andarine. PMID:20623476

  5. Comparison of accelerator mass spectrometric measurement with liquid scintillation counting measurement for the determination of {sup 14}C in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Yasuike, Kaeko, E-mail: k-yasuike@hokuriku-u.ac.j [Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, Kanazawa, Ishikawa 920-1181 (Japan); Yamada, Yoshimune [Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, Kanazawa, Ishikawa 920-1181 (Japan); Amano, Hikaru [AMS Management Section, Japan Atomic Energy Agency, 4-24, Minato-machi, Mutsu, Aomori 035-0064 (Japan)

    2010-04-15

    The concentrations of organically-bound {sup 14}C in tree-ring cellulose of a Japanese Black Pine grown in Shika-machi (37.0 deg. N, 136.8 deg. E) and those of a Japanese Cedar grown in Kanazawa (36.5 deg. N, 136.7 deg. E), Japan, were analyzed for the ring-years from 1989 to 1998 by the accelerator mass spectrometric measurement. The results were compared with those of the same samples analyzed by the liquid scintillation counting measurement to determine the reliability of liquid scintillation counting measurement. An important result of this study is that the sensitivity and reproducibility of accelerator mass spectrometric measurement was almost equal to that of liquid scintillation counting measurement.

  6. Differentiation of the Four Major Species of Cinnamons (C. burmannii, C. verum, C. cassia, and C. loureiroi) Using a Flow Injection Mass Spectrometric (FIMS) Fingerprinting Method

    OpenAIRE

    Chen, Pei; Sun, Jianghao; Ford, Paul

    2014-01-01

    A simple and efficient flow injection mass spectrometric (FIMS) method was developed to differentiate cinnamon (Cinnamomum) bark (CB) samples of the four major species (C. burmannii, C. verum, C. aromaticum, and C. loureiroi) of cinnamon. Fifty cinnamon samples collected from China, Vietnam, Indonesia, and Sri Lanka were studied using the developed FIMS fingerprinting method. The FIMS fingerprints of the cinnamon samples were analyzed using principal component analysis (PCA). The FIMS techniq...

  7. Preprocessing of Tandem Mass Spectrometric Data Based on Decision Tree Classification

    Institute of Scientific and Technical Information of China (English)

    Jing-Fen Zhang; Si-Min He; Jin-Jin Cai; Xing-Jun Cao; Rui-Xiang Sun; Yan Fu; Rong Zeng; Wen Gao

    2005-01-01

    In this study, we present a preprocessing method for quadrupole time-of-flight(Q-TOF) tandem mass spectra to increase the accuracy of database searching for peptide (protein) identification. Based on the natural isotopic information inherent in tandem mass spectra, we construct a decision tree after feature selection to classify the noise and ion peaks in tandem spectra. Furthermore, we recognize overlapping peaks to find the monoisotopic masses of ions for the following identification process. The experimental results show that this preprocessing method increases the search speed and the reliability of peptide identification.

  8. The IDA-80 measurement evaluation programme on mass spectrometric isotope dilution analysis of uranium and plutonium. Vol. 1

    International Nuclear Information System (INIS)

    The main objective was the acquisition of basic data on the uncertainties involved in the mass spectrometric isotope dilution analysis as applied to the determination of uranium and plutonium in active feed solutions of reprocessing plants. The element concentrations and isotopic compositions of all test materials used were determined by CBNM and NBS with high accuracy. The more than 60000 analytical data reported by the participating laboratories were evaluated by statistical methods applied mainly to the calculation of estimates of the variances for the different uncertainty components contributing to the total uncertainty of this analytical technique. Attention was given to such topics as sample ageing, influence of fission products, spike calibration, ion fractionation, Pu-241 decay correction, minor isotope measurement and errors in data transfer. Furthermore, the performance of the 'dried sample' technique and the 'in-situ' spiking method of undiluted samples of reprocessing fuel solution with U-235/Pu-242 metal alloy spikes, were tested successfully. Considerable improvement of isotope dilution analysis in this safeguards relevant application during the last decade is shown as compared to the results obtained in the IDA-72 interlaboratory experiment, organized by KfK in 1972 on the same subject. (orig./HP)

  9. Standard methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets

    International Nuclear Information System (INIS)

    Various methods are described in detail as to procedure, interferences, and limits of detection or applicability for the determination of Pu and various impurities in PuO2 powders and pellets. Methods for the determination of Pu are controlled-potential coulometry, ceric sulfate titration, and amperometric titration with Fe2+. Spectrophotometric methods are given for N and S, and a direct combustion-thermal conductivity method for the determination of total C is described. A pyrohydrolysis method is described for the determination of μg amounts of Cl- and F-. A mass spectrometric determination of the Pu isotopic content of the oxide is included, and general chemical methods are included for the determination of moisture in both powders and pellets and for total gas--exclusive of moisture--in pellets. Spectrochemical methods are described for the determination of rare earths, 36 trace elements whose recommended analytical spectral lines and concentration ranges are tabulated, and impurities occurring in the atom-ppB range

  10. Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria.

    Science.gov (United States)

    Kleigrewe, Karin; Almaliti, Jehad; Tian, Isaac Yuheng; Kinnel, Robin B; Korobeynikov, Anton; Monroe, Emily A; Duggan, Brendan M; Di Marzo, Vincenzo; Sherman, David H; Dorrestein, Pieter C; Gerwick, Lena; Gerwick, William H

    2015-07-24

    An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columbamides, a new class of di- and trichlorinated acyl amides with cannabinomimetic activity. Three species of cultured marine cyanobacteria, Moorea producens 3L, Moorea producens JHB, and Moorea bouillonii PNG, were subjected to genome sequencing and analysis for their recognizable biosynthetic pathways, and this information was then compared with their respective metabolomes as detected by MS profiling. By genome analysis, a presumed regulatory domain was identified upstream of several previously described biosynthetic gene clusters in two of these cyanobacteria, M. producens 3L and M. producens JHB. A similar regulatory domain was identified in the M. bouillonii PNG genome, and a corresponding downstream biosynthetic gene cluster was located and carefully analyzed. Subsequently, MS-based molecular networking identified a series of candidate products, and these were isolated and their structures rigorously established. On the basis of their distinctive acyl amide structure, the most prevalent metabolite was evaluated for cannabinomimetic properties and found to be moderate affinity ligands for CB1.

  11. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 μg/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

  12. Mass Spectrometric-Based Selected Reaction Monitoring of Protein Phosphorylation during Symbiotic Signaling in the Model Legume, Medicago truncatula.

    Science.gov (United States)

    Van Ness, Lori K; Jayaraman, Dhileepkumar; Maeda, Junko; Barrett-Wilt, Gregory A; Sussman, Michael R; Ané, Jean-Michel

    2016-01-01

    Unlike the major cereal crops corn, rice, and wheat, leguminous plants such as soybean and alfalfa can meet their nitrogen requirement via endosymbiotic associations with soil bacteria. The establishment of this symbiosis is a complex process playing out over several weeks and is facilitated by the exchange of chemical signals between these partners from different kingdoms. Several plant components that are involved in this signaling pathway have been identified, but there is still a great deal of uncertainty regarding the early events in symbiotic signaling, i.e., within the first minutes and hours after the rhizobial signals (Nod factors) are perceived at the plant plasma membrane. The presence of several protein kinases in this pathway suggests a mechanism of signal transduction via posttranslational modification of proteins in which phosphate is added to the hydroxyl groups of serine, threonine and tyrosine amino acid side chains. To monitor the phosphorylation dynamics and complement our previous untargeted 'discovery' approach, we report here the results of experiments using a targeted mass spectrometric technique, Selected Reaction Monitoring (SRM) that enables the quantification of phosphorylation targets with great sensitivity and precision. Using this approach, we confirm a rapid change in the level of phosphorylation in 4 phosphosites of at least 4 plant phosphoproteins that have not been previously characterized. This detailed analysis reveals aspects of the symbiotic signaling mechanism in legumes that, in the long term, will inform efforts to engineer this nitrogen-fixing symbiosis in important non-legume crops such as rice, wheat and corn. PMID:27203723

  13. Mass spectrometric analysis of stable carbon isotopes in abiogenic and biogenic natural compounds

    International Nuclear Information System (INIS)

    This report describes the general methodology of sup/13/ carbon analysis on mass spectrometer and various preparation systems developed for conversion of samples into isotopically non-fractionated and purified carbon dioxide. Laboratory standards required for sup/13/ C analysis have been calibrated against international standards. The reproducibility/accuracy of sample preparation and analysis on mass spectrometer for sup/13/ C or sup/12/ C measurement is well within the internationally acceptable limits. (author)

  14. Mass spectrometric base composition profiling: Implications for forensic mtDNA databasing

    OpenAIRE

    Eduardoff, Mayra; Huber, Gabriela; Bayer, Birgit; Schmid, Dagmar; Anslinger, Katja; Göbel, Tanja; Zimmermann, Bettina; Schneider, Peter M; Röck, Alexander W; Parson, Walther

    2013-01-01

    In forensic genetics mitochondrial DNA (mtDNA) is usually analyzed by direct Sanger-type sequencing (STS). This method is known to be laborious and sometimes prone to human error. Alternative methods have been proposed that lead to faster results. Among these are methods that involve mass-spectrometry resulting in base composition profiles that are, by definition, less informative than the full nucleotide sequence. Here, we applied a highly automated electrospray ionization mass spectrometry ...

  15. Vacuum-Ultraviolet Photoionization and Mass Spectrometric Characterization of Lignin Monomers Coniferyl and Sinapyl Alcohols

    OpenAIRE

    Takahashi, Lynelle K.

    2011-01-01

    The fragmentation mechanisms of monolignols under various energetic processes are studied with jet-cooled thermal desorption molecular beam (TDMB) mass spectrometry (MS), 25 keV Bi3+ secondary ion MS (SIMS), synchrotron vacuum-ultraviolet secondary neutral MS (VUV-SNMS) and theoretical methods. Experimental and calculated appearance energies of fragments observed in TDMB MS indicate that the coniferyl alcohol photoionization mass spectra contain the molecular parent and several dissociative ...

  16. Remote Mass Spectrometric Sampling of Electrospray- and Desorption Electrospray-Generated Ions Using an Air Ejector

    OpenAIRE

    Dixon, R. Brent; Bereman, Michael S.; Muddiman, David C.; Hawkridge, Adam M.

    2007-01-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrom...

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

    Directory of Open Access Journals (Sweden)

    Richard D. Smith

    2006-04-01

    Full Text Available Progress is reviewed towards the development of a global strategy that aims to extend the sensitivity, dynamic range, comprehensiveness and throughput of proteomic measurements based upon the use of high performance separations and mass spectrometry. The approach uses high accuracy mass measurements from Fourier transform ion cyclotron resonance mass spectrometry (FTICR to validate peptide ‘accurate mass tags’ (AMTs produced by global protein enzymatic digestions for a specific organism, tissue or cell type from ‘potential mass tags’ tentatively identified using conventional tandem mass spectrometry (MS/MS. This provides the basis for subsequent measurements without the need for MS/ MS. High resolution capillary liquid chromatography separations combined with high sensitivity, and high resolution accurate FTICR measurements are shown to be capable of characterizing peptide mixtures of more than 105 components. The strategy has been initially demonstrated using the microorganisms Saccharomyces cerevisiae and Deinococcus radiodurans. Advantages of the approach include the high confidence of protein identification, its broad proteome coverage, high sensitivity, and the capability for stableisotope labeling methods for precise relative protein abundance measurements.

  18. Vacuum-Ultraviolet Photoionization and Mass Spectrometric Characterization of Lignin Monomers Coniferyl and Sinapyl Alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Lynelle K.; Zhou, Jia; Kostko, Oleg; Golan, Amir; Leone, Stephen R.; Ahmed, Musahid

    2011-02-09

    The fragmentation mechanisms of monolignols under various energetic processes are studied with jet-cooled thermal desorption molecular beam (TDMB) mass spectrometry (MS), 25 keV Bi3+ secondary ion MS (SIMS), synchrotron vacuum-ultraviolet secondary neutral MS (VUV-SNMS) and theoretical methods. Experimental and calculated appearance energies of fragments observed in TDMB MS indicate that the coniferyl alcohol photoionization mass spectra contain the molecular parent and several dissociative photoionization products. Similar results obtained for sinapyl alcohol are also discussed briefly. Ionization energies of 7.60 eV ? 0.05 eV for coniferyl alcohol and<7.4 eV for both sinapyl and dihydrosinapyl alcohols are determined. The positive ion SIMS spectrum of coniferyl alcohol shares few characteristic peaks (m/z = 137 and 151) with the TDMB mass spectra, shows extensive fragmentation, and does not exhibit clear molecular parent signals. VUV-SNMS spectra, on the other hand, are dominated by the parent ion and main fragments also present in the TDMB spectra. Molecular fragmentation in VUV-SNMS spectra can be reduced by increasing the extraction delay time. Some features resembling the SIMS spectra are also observed in the desorbed neutral products. The monolignol VUV-SNMS peaks shared with the TDMB mass spectra suggest that dissociative photoionization of ion-sputtered neutral molecules predominate in the VUV-SNMS mass spectra, despite the extra internal energy imparted in the initial ion impact. The potential applications of these results to imaging mass spectrometry of bio-molecules are discussed.

  19. Focused analyte spray emission apparatus and process for mass spectrometric analysis

    Science.gov (United States)

    Roach, Patrick J.; Laskin, Julia; Laskin, Alexander

    2012-01-17

    An apparatus and process are disclosed that deliver an analyte deposited on a substrate to a mass spectrometer that provides for trace analysis of complex organic analytes. Analytes are probed using a small droplet of solvent that is formed at the junction between two capillaries. A supply capillary maintains the droplet of solvent on the substrate; a collection capillary collects analyte desorbed from the surface and emits analyte ions as a focused spray to the inlet of a mass spectrometer for analysis. The invention enables efficient separation of desorption and ionization events, providing enhanced control over transport and ionization of the analyte.

  20. Uranyl-water-containing complexes: solid-state UV-MALDI mass spectrometric and IR spectroscopic approach for selective quantitation.

    Science.gov (United States)

    Ivanova, Bojidarka; Spiteller, Michael

    2014-01-01

    Since primary environmental concept for long storage of nuclear waste involved assessment of water in uranium complexes depending on migration processes, the paper emphasized solid-state matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) and IR spectroscopic determination of UO2(NO3)2·6H2O; UO2(NO3)2·3H2O, α-, β-, and γ-UO3 modifications; UO3·xH2O (x = 1 or 2); UO3·H2O, described chemically as UO2(OH)2, β- and γ-UO2(OH)2 modifications; and UO4·2H2O, respectively. Advantages and limitation of vibrational spectroscopic approach are discussed, comparing optical spectroscopic data and crystallographic ones. Structural similarities occurred in α-γ modifications of UO3, and UO2(OH)2 compositions are analyzed. Selective speciation achieved by solid-state mass spectrometry is discussed both in terms of its analytical contribution for environmental quality assurance and assessment of radionuclides, and fundamental methodological interest related the mechanistic complex water exchange of UO3·H2O forms in the gas phase. In addition to high selectivity and precision, UV-MALDI-MS, employing an Orbitrap analyzer, was a method that provided fast steps that limited sample pretreatment techniques for direct analysis including imaging. Therefore, random and systematic errors altering metrology and originating from the sample pretreatment stages in the widely implemented analytical protocols for environmental sampling determination of actinides are significantly reduced involving the UV-MALDI-Orbitrap-MS method. The method of quantum chemistry is utilized as well to predict reliably the thermodynamics and nature of U-O bonds in uranium species in gas and condensed phases. PMID:23942998

  1. Mass Spectrometric Evidence of Heparin Disaccharides for the Catalytic Characterization of A Novel Endolytic Heparinase

    Institute of Scientific and Technical Information of China (English)

    Yapeng CHAO; Shaoxiang XIONG; Xiulan CHENG; Shijun QIAN

    2004-01-01

    Heparinase from different sources can eliminate heparin or/and heparan sulfate into various low-molecular weight heparins with different characteristics. Porcine intestinal mucosa heparin was degraded into a series of oligosaccharides by a novel heparinase from the species Sphingobacterium. Disaccharide components from the digests were separated and purified by ultrafiltration and HPLC. Five major peaks appeared as three types according to their retention time. The mass spectrometry of peak Ⅰ mainly gave the non-sulfated disaccharide with the mass of 379 Da. Peak Ⅱ and Ⅲ were indicated as two major monosulfated disaccharides with molecular mass of 417 and 459 Da respectively. Moreover, the peak Ⅲ represented an Nacetyl disaccharide. Both peak Ⅳ and Ⅴ showed the same mass of 496 Da, hinting that they were disulfatesubstituted disaccharides. No trisulfate-substituted disaccharides were detected in the mixture of the heparin digest though they were abundant in the heparin structure. The results revealed that the heparinase might specifically cut the sites with low sulfated domain in heparin.

  2. Gas chromatographic-mass spectrometric analysis of tar compounds formed during pyrolysis of rice husks

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Stevens, T.W.; Hovestad, A.; Skolnik, V.; Visser, R.

    1991-01-01

    Pyrolysis of agricultural waste to produce fuel gas involves formation of tars as noxious by-products. In this paper the qualitative analysis of tars formed during pyrolysis of rice husks is presented, based on identification by gas chromatography—mass spectrometry and interpolation of retention tim

  3. Application of mass spectrometric techniques to delineate the modes-of-action of anticancer metallodrugs

    NARCIS (Netherlands)

    Hartinger, Christian G.; Groessl, Michael; Meier, Samuel M.; Casini, Angela; Dyson, Paul J.

    2013-01-01

    Mass spectrometry (MS) has emerged as an important tool for studying anticancer metallodrugs in complex biological samples and for characterising their interactions with biomolecules and potential targets on a molecular level. The exact modes-of-action of these coordination compounds and especially

  4. FINAL REPORT. MASS SPECTROMETRIC FINGERPRINTING OF TANK WASTES USING TUNABLE, ULTRAFAST INFRARED LASERS

    Science.gov (United States)

    The principal scientific thrust of this project was to demonstrate a novel method for precision matrix-assisted laser desorption-ionization (MALDI) mass spectrometry (MS) of model tank-waste materials, using the sodium nitrate component of the tank waste both as the matrix and as...

  5. Electrochemical oxidation and cleavage of peptides analyzed with on-line mass spectrometric detection

    NARCIS (Netherlands)

    Permentier, H.P.; Jurva, U; Barroso, B.; Bruins, A.P.

    2003-01-01

    An on-line electrochernistry/electrospray mass spectrometry system (EC/MS) is described that allows fast analysis of the oxidation products of peptides. A range of peptides was oxidized in an electrochemical cell by application of a potential ramp from 0 to 1.5 V during passage of the sample. Electr

  6. Heterogeneous nuclear ribonucleoproteins C1/C2 identified as autoantigens by biochemical and mass spectrometric methods

    DEFF Research Database (Denmark)

    Heegaard, N H; Larsen, Martin Røssel; Muncrief, T;

    2000-01-01

    gel and their contents were analyzed by matrix-assisted laser desorption-ionization (MALDI) or nanoelectrospray ionization time-of-flight (TOF) tandem mass spectrometry (MS) after in-gel digestion with trypsin. A database search identified the proteins as the C1 and C2 heterogeneous nuclear...

  7. Mass spectrometric study of selected precursors and degradation products of chemical warfare agents.

    Science.gov (United States)

    Papousková, Barbora; Bednár, Petr; Frysová, Iveta; Stýskala, Jakub; Hlavác, Jan; Barták, Petr; Ulrichová, Jitka; Jirkovský, Jaromír; Lemr, Karel

    2007-12-01

    Selected precursors and degradation products of chemical warfare agents namely N,N-dialkylaminoethane-2-ols, N,N-dialkylaminoethyl-2-chlorides and some of related N-quaternary salts were studied by means of electrospray ionization-multiple tandem mass spectrometry (ESI-MS(n)). Proposed structures were confirmed with accurate mass measurement. General fragmentation patterns of these compounds are discussed in detail and suggested processes are confirmed using deuterated standards. The typical processes are elimination of alkene, hydrogen chloride, or water, respectively. Besides, elimination of ethene from propyl chain under specific conditions was observed and unambiguously confirmed using exact mass measurement and labelled standard. The potential of mass spectrometry to distinguish the positional isomers occurring among the studied compounds is reviewed in detail using two different MS instruments (i.e. ion trap and hybrid quadrupole-time of flight (Q-TOF) analyzer). A new microcolumn liquid chromatography (microLC)/MS(n) method was designed for the cases where the resolution based solely on differences in fragmentation is not sufficient. Low retention of the derivatives on reversed phase (RP) was overcome by using addition of less typical ion pairing agent (1 mM/l, 3,5-dinitrobenzoic acid) to the mobile phase (mixture water : acetonitrile). PMID:18085550

  8. Vacuum-ultraviolet photoionization and mass spectrometric characterization of lignin monomers coniferyl and sinapyl alcohols.

    Science.gov (United States)

    Takahashi, Lynelle K; Zhou, Jia; Kostko, Oleg; Golan, Amir; Leone, Stephen R; Ahmed, Musahid

    2011-04-21

    The fragmentation mechanisms of monolignols under various energetic processes are studied with jet-cooled thermal desorption molecular beam (TDMB) mass spectrometry (MS), 25 keV Bi(3)(+) secondary ion MS (SIMS), synchrotron vacuum-ultraviolet secondary neutral MS (VUV-SNMS) and theoretical methods. Experimental and calculated appearance energies of fragments observed in TDMB MS indicate that the coniferyl alcohol photoionization mass spectra contain the molecular parent and several dissociative photoionization products. Similar results obtained for sinapyl alcohol are also discussed briefly. Ionization energies of 7.60 eV ± 0.05 eV for coniferyl alcohol and SNMS spectra, on the other hand, are dominated by the parent ion and main fragments also present in the TDMB spectra. Molecular fragmentation in VUV-SNMS spectra can be reduced by increasing the extraction delay time. Some features resembling the SIMS spectra are also observed in the desorbed neutral products. The monolignol VUV-SNMS peaks shared with the TDMB mass spectra suggest that dissociative photoionization of ion-sputtered neutral molecules predominate in the VUV-SNMS mass spectra, despite the extra internal energy imparted in the initial ion impact. The potential applications of these results to imaging MS of biomolecules are discussed. PMID:21410275

  9. MALDI-TOF mass spectrometric detection of multiplex single base extended primers

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Sanchez Sanchez, Juan Jose; Børsting, Claus;

    2004-01-01

    One of the most promising techniques for typing of multiple single-nucleotide polymorphism (SNP) is detection of single base extension primers (SBE) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a new MALDI-TOF MS protocol for typing...

  10. Photoionization mass spectrometric studies of selected compounds in a molecular beam

    Energy Technology Data Exchange (ETDEWEB)

    Trott, W.M.

    1979-03-01

    Photoionization efficiency curves have been measured at moderate to high resolution for several species produced in supersonic molecular beams of acetone, acetone-d/sub 6/ and CS/sub 2/. The molecular beam photoionization mass spectrometer which has been assembled for this work is described. The performance of this instrument has been characterized by a number of experiments and calculations.

  11. Combination of a SAW-biosensor with MALDI mass spectrometric analysis.

    Science.gov (United States)

    Treitz, G; Gronewold, T M A; Quandt, E; Zabe-Kühn, M

    2008-05-15

    A S-sens K5 surface acoustic wave biosensor was coupled with mass spectrometry (SAW-MS) for the analysis of a protein complex consisting of human blood clotting cascade factor alpha-thrombin and human antithrombin III, a specific blood plasma inhibitor of thrombin. Specific binding of antithrombin III to thrombin was recorded as a function of time with a S-sens K5 biosensor. Two out of five elements of the sensor chip were used as references. To the remaining three elements coated with RNA anti-thrombin aptamers, thrombin and antithrombin III were bound consecutively. The biosensor measures mass changes on the chip surface showing that 20% of about 400fmol/cm2 thrombin formed a complex with the 1.7-times larger antithrombin III. Mass spectrometry (MS) was applied to identify the bound proteins. Sensor chips with aptamer-captured (1) thrombin and (2) thrombin-antithrombin III complex (TAT-complex) were digested with proteases on the sensor element and subsequently identified by peptide mass fingerprint (PMF) with matrix assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry. A significant identification of thrombin was achieved by measuring the entire digest with MALDI-ToF MS directly from the sensor chip surface. For the significant identification of both proteins in the TAT-complex, the proteolytic peptides had to be separated by nano-capillary-HPLC prior to MALDI-ToF MS. SAW-MS is applicable to protein interaction analysis as in functional proteomics and to miniaturized diagnostics. PMID:18316185

  12. Mass spectrometric screening and identification of acidic metabolites in fulvic acid fractions of contaminated groundwater.

    Science.gov (United States)

    Jobelius, Carsten; Frimmel, Fritz H; Zwiener, Christian

    2014-05-01

    The anaerobic microbial degradation of aromatic and heterocyclic compounds is a prevalent process in contaminated groundwater systems. The introduction of functional groups into the contaminant molecules often results in aromatic and heterocyclic and succinic acids. These metabolites can be used as indicators for prevailing degradation processes. Therefore, there is a strong interest in developing analytical methods for screening and identification of these metabolites. In this study, neutral loss scans (NLS) by liquid chromatography-electrospray ionization/tandem mass spectrometry with losses of CO2 (NL ∆m/z = 44) and C2H4(CO2)2 (NL ∆m/z = 116) were applied for the first time successfully to screen selectively for acidic and succinic metabolites of aromatic and heterocyclic contaminants in two fulvic acid fractions from a contaminated site and a downstream region of a tar oil-polluted groundwater. Identification of these preselected signals was performed by high-resolution mass spectrometry with a liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry instrument. High-resolution mass and mass fragmentation data were then compared with a list of known metabolites from a literature search or matched with chemical databases supported with in silico fragmentation. Based on authentic analytical standards, several compounds from NLS were identified (e.g., 4-hydroxy-3-methylbenzoic acid, benzylsuccinic acid, naphthyl-2-methylsuccinic acid, 2-carboxyindane, and 2-carboxybenzothiophene) and tentatively identified (e.g., benzofuranmethylsuccinic acid and dihydrocarboxybenzothiophene) as aromatic, phenolic, heterocyclic, and succinic acids. The acidic metabolites were found exclusively in the contaminated region of the aquifer which indicates active biodegradation processes and no relevant occurrence of acidic metabolites in the downstream region.

  13. Mass Spectrometric Detection of Botulinum Neurotoxin by Measuring its Activity in Serum and Milk

    Science.gov (United States)

    Kalb, Suzanne R.; Pirkle, James L.; Barr, John R.

    Botulinum neurotoxins (BoNTs) are bacterial protein toxins which are considered likely agents for bioterrorism due to their extreme toxicity and high availability. A new mass spectrometry based assay called Endopep MS detects and defines the toxin serotype in clinical and food matrices via toxin activity upon a peptide substrate which mimics the toxin's natural target. Furthermore, the subtype of the toxin is differentiated by employing mass spectrometry based proteomic techniques on the same sample. The Endopep-MS assay selectively detects active BoNT and defines the serotype faster and with sensitivity greater than the mouse bioassay. One 96-well plate can be analyzed in under 7 h. On higher level or "hot" samples, the subtype can then be differentiated in less than 2 h with no need for DNA.

  14. High-production laser ion source using plasma focusing for mass spectrometric analysis of solids

    International Nuclear Information System (INIS)

    A laser-plasma ion source having an ion collection coefficient of about 3x10-8 has been designed. The laser is an alumo-yttrium garnet giant pulse FM laser generating pulses with repetition rate of 100 Hz and energy of 20 mJ per pulse. When a sample is affected by a high-power light, plasma is formed the ions of which are extracted by the field of the ''spherical diode'', accelerated and focused on the mass-spectrometer aperture. This plasma-focused laser ion source in combination with a mass-spectrometer may be used for the massspectrometric analysis of solid bodies. The results of such analysis are consistent with the data known from previous publications

  15. Liquid chromatography/electrospray ionization mass spectrometric characterization of Harpagophytum in equine urine and plasma.

    Science.gov (United States)

    Colas, Cyril; Garcia, Patrice; Popot, Marie-Agnès; Bonnaire, Yves; Bouchonnet, Stéphane

    2006-01-01

    A method has been developed for the analysis and characterization in equine urine and plasma of iridoid glycosides: harpagide, harpagoside and 8-para-coumaroyl harpagide, which are the main active principles of Harpagophytum, a plant with antiinflammatory properties. The method involves liquid chromatography coupled with positive electrospray ionization mass spectrometry. The addition of sodium or lithium chloride instead of formic acid in the eluting solvent has been studied in order to enhance the signal and to modify the ion's internal energy. Fragmentation pathways and associated patterns are proposed for each analyte. A comparison of three types of mass spectrometer: a 3D ion trap, a triple quadrupole and a linear ion trap, has been conducted. The 3D ion trap was selected for drug screening analysis whereas the linear ion trap was retained for identification and quantitation analysis. PMID:17044124

  16. Capillary liquid chromatography using laser-based and mass spectrometric detection. Final technical progress report, September 1, 1989--January 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M.J.; Cook, K.D.

    1992-09-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  17. Mass spectrometric analysis of 40 S ribosomal proteins from Rat-1 fibroblasts.

    Science.gov (United States)

    Louie, D F; Resing, K A; Lewis, T S; Ahn, N G

    1996-11-01

    Although sequences of most mammalian ribosomal proteins are available, little is known about the post-translational processing of ribosomal proteins. To examine their post-translational modifications, 40 S subunit proteins purified from Rat-1 fibroblasts and their peptides were analyzed by liquid chromatography coupled with electrospray mass spectrometry. Of 41 proteins observed, 36 corresponded to the 32 rat 40 S ribosomal proteins with known sequences (S3, S5, S7, and S24 presented in two forms). The observed masses of S4, S6-S8, S13, S15a, S16, S17, S19, S27a, S29, and S30 matched those predicted. Sa, S3a, S5, S11, S15, S18, S20, S21, S24, S26-S28, and an S7 variant showed changes in mass that were consistent with N-terminal demethionylation and/or acetylation (S5 and S27 also appeared to be internally formylated and acetylated, respectively). S23 appeared to be internally hydroxylated or methylated. S2, S3, S9, S10, S12, S14, and S25 showed changes in mass inconsistent with known covalent modifications (+220, -75, +86, +56, -100, -117, and -103 Da, respectively), possibly representing novel post-translational modifications or allelic sequence variation. Five unidentified proteins (12,084, 13,706, 13,741, 13,884, and 34, 987 Da) were observed; for one, a sequence tag (PPGPPP), absent in any known ribosomal proteins, was determined, suggesting that it is a previously undescribed ribosome-associated protein. This study establishes a powerful method to rapidly analyze protein components of large biological complexes and their covalent modifications.

  18. Gas chromatographic/mass spectrometric determination of lysergic acid diethylamide (LSD) in serum samples.

    Science.gov (United States)

    Musshoff, F; Daldrup, T

    1997-08-01

    A sensitive method for the detection and quantification of lysergic acid diethylamide (LSD) in serum samples is described. After liquid-liquid extraction the trimethylsilyl derivative of LSD is detected by gas chromatography-mass spectrometry. Experiments with spiked samples resulted in a recovery of 76%, the coefficient of variation was 9.3%. Excellent linearity was obtained over the range 0.1-10 ng ml-1. Additionally experiments demonstrating the light sensitivity of LSD are presented together with casuistics.

  19. Gas chromatographic-mass spectrometric analysis of tar compounds formed during pyrolysis of rice husks

    OpenAIRE

    Haanappel, V.A.C.; Stevens, T.W.; Hovestad, A.; Skolnik, V.; Visser, R.

    1991-01-01

    Pyrolysis of agricultural waste to produce fuel gas involves formation of tars as noxious by-products. In this paper the qualitative analysis of tars formed during pyrolysis of rice husks is presented, based on identification by gas chromatography—mass spectrometry and interpolation of retention times on a polyaromatic hydrocarbon index scale. The influence of some reaction parameters on product formation is briefly discussed.

  20. Visualizing Dermal Permeation of Sodium Channel Modulators by Mass Spectrometric Imaging

    OpenAIRE

    Eberlin, Livia S; Mulcahy, John V.; Tzabazis, Alexander; Zhang, Jialing; Liu, Huwei; Logan, Matthew M.; Roberts, Heather J.; Lee, Gordon K.; Yeomans, David C.; Du Bois, Justin; Zare, Richard N.

    2014-01-01

    Determining permeability of a given compound through human skin is a principal challenge owing to the highly complex nature of dermal tissue. We describe the application of an ambient mass spectrometry imaging method for visualizing skin penetration of sodium channel modulators, including novel synthetic analogs of natural neurotoxic alkaloids, topically applied ex vivo to human skin. Our simple and label-free approach enables successful mapping of the transverse and lateral diffusion of smal...

  1. Mass spectrometric study of the phase boundaries of the CdS-CdTe system

    Energy Technology Data Exchange (ETDEWEB)

    Nunoue, S.Y.; Hemmi, T.; Kato, E. (Dept. of Materials Science and Engineering, Waseda Univ., Shinjuku-ku Tokyo 160 (JP))

    1990-04-01

    An isothermal evaporation method by means of a Knudsen cell-mass spectrometer combination has been applied to the determination of the phase boundaries in the CdS-CdTe system in the temperature range of 650{degrees}--720{degrees}C. The phase boundaries obtained were compared with published phase boundaries. The advantages of the present method over the x-ray diffraction technique are discussed.

  2. Calibration of mass spectrometric measurements of gas phase reactions on steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Falk, H., E-mail: heinzfalk@unitybox.de [Scientific Consultancy, Kleve (Germany); Falk, M. [Falk Steuerungssysteme GmbH, Stadthagen (Germany); Wuttke, T. [FuE-EV ThyssenKrupp Steel Europe, Dortmund (Germany)

    2015-03-01

    The sampling of the surface-near gas composition using a mass spectrometer (MS-Probe) is a valuable tool within a hot dip process simulator. Since reference samples with well characterized surface coverage are usually not available, steel samples can deliver quantifiable amounts of the process relevant species H{sub 2}O, CO and H{sub 2} using the decarburization reaction with water vapor. Such “artificial calibration samples” (ACS) can be used for the calibration of the MS-Probe measurements. The carbon release rate, which is governed by the diffusion law, was determined by GDOES, since the diffusion coefficients of carbon in steel samples are usually not known. The measured carbon concentration profiles in the ACS after the thermal treatment confirmed the validity of the diffusion model described in this paper. The carbon bulk concentration > 100 ppm is sufficient for the use of a steel material as ACS. The experimental results reported in this paper reveal, that with the MS-Probe the LOQ of less than one monolayer of iron oxide can be achieved. - Highlights: • Gas to surface reactions at steel sheets is monitored with a mass spectrometer on-line. • The experimental data are calibrated in absolute terms as oxide mass densities. • Standard steel samples can be used for the calibration procedure. • Additional GDOES analysis of the carbon depletion in the calibration samples was carried out. • Limits of quantitation below one monolayer of oxide surface coverage were achieved.

  3. Process and Formulation Effects on Protein Structure in Lyophilized Solids Using Mass Spectrometric Methods.

    Science.gov (United States)

    Iyer, Lavanya K; Sacha, Gregory A; Moorthy, Balakrishnan S; Nail, Steven L; Topp, Elizabeth M

    2016-05-01

    Myoglobin (Mb) was lyophilized in the absence (Mb-A) and presence (Mb-B) of sucrose in a pilot-scale lyophilizer with or without controlled ice nucleation. Cake morphology was characterized using scanning electron microscopy, and changes in protein structure were monitored using solid-state Fourier-transform infrared spectroscopy, solid-state hydrogen-deuterium exchange-mass spectrometry, and solid-state photolytic labeling-mass spectrometry (ssPL-MS). The results showed greater variability in nucleation temperature and irregular cake structure for formulations lyophilized without controlled nucleation. Controlled nucleation resulted in nucleation at ∼(-5°C) and uniform cake structure. Formulations containing sucrose showed better retention of protein structure by all measures than formulations without sucrose. Samples lyophilized with and without controlled nucleation were similar by most measures of protein structure. However, ssPL-MS showed the greatest photoleucine incorporation and more labeled regions for Mb-B lyophilized with controlled nucleation. The data support the use of solid-state hydrogen-deuterium exchange-mass spectrometry and ssPL-MS to study formulation and process-induced conformational changes in lyophilized proteins. PMID:27044943

  4. Determination of total body water by a simple and rapid mass spectrometric method.

    Science.gov (United States)

    Van Kreel, B K; Van der Vegt, F; Meers, M; Wagenmakers, T; Westerterp, K; Coward, A

    1996-01-01

    A rapid and inexpensive method was developed to determine deuterium enrichment in body fluids. This is achieved by converting water into acetylene. To vacutainer tubes a small amount of calcium carbide is added. The tubes are evacuated and 25 microliters of sample are injected through the stopper. The reaction takes place spontaneously at room temperature in a few seconds. Enrichment at mass 27 compared with mass 26 can be determined by continuous flow isotope ratio mass spectrometry without any interference from the carrier gas helium. A series of D2O samples diluted with increasing amounts of H2O is prepared at the time of measurement of the biological samples and the measured ratios are used to calculate the isotope dilution of the unknown. The relative error of the method is 1.6% when a dose of 25 ml kg-1 is administered to the patient. The method was compared with two different methods in use in other laboratories, by a published method The means of the differences were -0.1 and 0.08 1, respectively, with standard deviations of 0.63 and 3.0.

  5. Ultrahigh resolution mass spectrometric characterization of organic aerosol from European and Chinese cities

    Science.gov (United States)

    Wang, Kai; Huang, Ru-Jin; Hoffmann, Thorsten

    2016-04-01

    Organic aerosol constitutes a substantial fraction (20-90%) of submicrometer aerosol mass, playing an important role in air quality and human health. Over the past few years, ultra-high resolution mass spectrometry (UHRMS) has been applied to elucidate the chemical composition of ambient aerosols. However, most of the UHRMS studies used direct infusion without prior separation by liquid chromatography, which may cause the loss of individual compound information and interference problems. In the present study, urban ambient aerosol with particle diameter Beijing, China, respectively. Two pretreatment procedures were applied to extract the organic compounds from the filter samples: One method uses a mixture of acetonitrile and water, the other uses pure water and prepared for the extraction of humic-like substances. The extracts were analyzed by ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometer in both negative and the positive modes. The effects of pretreatment procedures on the characterization of organic aerosol and the city-wise difference in chemical composition of organic aerosol will be discussed in detail.

  6. Chemometric profile of root extracts of Rhodiola imbricata Edgew. with hyphenated gas chromatography mass spectrometric technique.

    Science.gov (United States)

    Tayade, Amol B; Dhar, Priyanka; Kumar, Jatinder; Sharma, Manu; Chauhan, Rajinder S; Chaurasia, Om P; Srivastava, Ravi B

    2013-01-01

    Rhodiola imbricata Edgew. (Rose root or Arctic root or Golden root or Shrolo), belonging to the family Crassulaceae, is an important food crop and medicinal plant in the Indian trans-Himalayan cold desert. Chemometric profile of the n-hexane, chloroform, dichloroethane, ethyl acetate, methanol, and 60% ethanol root extracts of R. imbricata were performed by hyphenated gas chromatography mass spectrometry (GC/MS) technique. GC/MS analysis was carried out using Thermo Finnigan PolarisQ Ion Trap GC/MS MS system comprising of an AS2000 liquid autosampler. Interpretation on mass spectrum of GC/MS was done using the NIST/EPA/NIH Mass Spectral Database, with NIST MS search program v.2.0g. Chemometric profile of root extracts revealed the presence of 63 phyto-chemotypes, among them, 1-pentacosanol; stigmast-5-en-3-ol, (3β,24S); 1-teracosanol; 1-henteracontanol; 17-pentatriacontene; 13-tetradecen-1-ol acetate; methyl tri-butyl ammonium chloride; bis(2-ethylhexyl) phthalate; 7,8-dimethylbenzocyclooctene; ethyl linoleate; 3-methoxy-5-methylphenol; hexadecanoic acid; camphor; 1,3-dimethoxybenzene; thujone; 1,3-benzenediol, 5-pentadecyl; benzenemethanol, 3-hydroxy, 5-methoxy; cholest-4-ene-3,6-dione; dodecanoic acid, 3-hydroxy; octadecane, 1-chloro; ethanone, 1-(4-hydroxyphenyl); α-tocopherol; ascaridole; campesterol; 1-dotriacontane; heptadecane, 9-hexyl were found to be present in major amount. Eventually, in the present study we have found phytosterols, terpenoids, fatty acids, fatty acid esters, alkyl halides, phenols, alcohols, ethers, alkanes, and alkenes as the major group of phyto-chemotypes in the different root extracts of R. imbricata. All these compounds identified by GC/MS analysis were further investigated for their biological activities and it was found that they possess a diverse range of positive pharmacological actions. In future, isolation of individual phyto-chemotypes and subjecting them to biological activity will definitely prove fruitful results in

  7. Raman spectroscopic and mass spectrometric investigations of the hydrogen isotopes and isotopically labelled methane

    Energy Technology Data Exchange (ETDEWEB)

    Jewett, J.R., Fluor Daniel Hanford

    1997-02-24

    Suitable analytical methods must be tested and developed for monitoring the individual process steps within the fuel cycle of a fusion reactor and for tritium accountability. The utility of laser-Raman spectroscopy accompanied by mass spectrometry with an Omegatron was investigated using the analysis of all hydrogen isotopes and isotopically labeled methanes as an example. The Omegatron is useful for analyzing all hydrogen isotopes mixed with the stable helium isotopes. The application of this mass spectrometer were demonstrated by analyzing mixtures of deuterated methanes. In addition, it was employed to study the radiochemical Witzbach exchange reaction between tritium and methanes. A laser-Raman spectrometer was designed for analysis of tritium-containing gases and was built from individual components. A tritium-compatible, metal-sealed Raman cuvette having windows with good optical properties and additional means for measuring the stray light was first used successfully in this work. The Raman spectra of the hydrogen isotopes were acquired in the pure rotation mode and in the rotation-vibration mode and were used for on. The deuterated methanes were measured by Raman spectroscopy, the wavenumbers determined were assigned to the corresponding vibrations, and the wavenumbers for the rotational fine-structure were summarized in tables. The fundamental Vibrations of the deuterated methanes produced Witzbach reactions were detected and assigned. The fundamental vibrations of the molecules were obtained with Raman spectroscopy for the first time in this work. The @-Raman spectrometer assembled is well suited for the analysis of tritium- containing gases and is practical in combination with mass spectrometry using an Omegatron, for studying gases used in fusion.

  8. Use of flow injection mass spectrometric fingerprinting and chemometrics for differentiation of three black cohosh species

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huilian [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); Key Laboratory of Modern Preparation of TCM, Jiangxi University of Traditional Chinese Medicine, Ministry of Education, Nanchang, Jiangxi Province (China); Sun, Jianghao [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); McCoy, Joe-Ann [The North Carolina Arboretum Germplasm Repository, UNC Affiliate Campus, Asheville, NC (United States); Zhong, Haiyan [College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan Province (China); Fletcher, Edward J. [Strategic Sourcing, Inc., Banner Elk, NC 28604 (United States); Harnly, James, E-mail: harnly.james@ars.usda.gov [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); Chen, Pei, E-mail: pei.chen@ars.usda.gov [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States)

    2015-03-01

    Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. This method has proven to be a powerful tool for botanical authentication and in this study it was used to distinguish between three Actaea species prior to a more detailed chemical analysis using ultra high-performance liquid chromatography high-resolution mass spectrometry (UHPLC–HRMS). Black cohosh has become increasingly popular as a dietary supplement in the United States for the treatment of symptoms related to menopause. However, it has been known to be adulterated with the Asian Actaea dahurica (Turcz. ex Fisch. & C.A.Mey.) Franch. species (syn. Cimicifuga dahurica (Turcz.) Maxim). Existing methods for identification of black cohosh and differentiation of Actaea species are usually lengthy, laborious, and lack robustness, often based on the comparison of a few pre-selected components. Chemical fingerprints were obtained for 77 black cohosh samples and their related species using FIMS in the negative ion mode. The analysis time for each sample was less than 2 min. All data were processed using principal component analysis (PCA). FIMS fingerprints could readily differentiate all three species. Representative samples from each of the three species were further examined using UHPLC–MS to provide detailed profiles of the chemical differences between the three species and were compared to the PCA loadings. This study demonstrates a simple, fast, and easy analytical method that can be used to differentiate A. racemosa, Actaea podocarpa, and A. dahurica. - Highlights: • Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. • FIMS can discriminate between A. dahurica, A. podocarpa, and A. racemosa. • FIMS is a valuable screening tool for authentication of botanicals.

  9. Use of flow injection mass spectrometric fingerprinting and chemometrics for differentiation of three black cohosh species

    International Nuclear Information System (INIS)

    Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. This method has proven to be a powerful tool for botanical authentication and in this study it was used to distinguish between three Actaea species prior to a more detailed chemical analysis using ultra high-performance liquid chromatography high-resolution mass spectrometry (UHPLC–HRMS). Black cohosh has become increasingly popular as a dietary supplement in the United States for the treatment of symptoms related to menopause. However, it has been known to be adulterated with the Asian Actaea dahurica (Turcz. ex Fisch. & C.A.Mey.) Franch. species (syn. Cimicifuga dahurica (Turcz.) Maxim). Existing methods for identification of black cohosh and differentiation of Actaea species are usually lengthy, laborious, and lack robustness, often based on the comparison of a few pre-selected components. Chemical fingerprints were obtained for 77 black cohosh samples and their related species using FIMS in the negative ion mode. The analysis time for each sample was less than 2 min. All data were processed using principal component analysis (PCA). FIMS fingerprints could readily differentiate all three species. Representative samples from each of the three species were further examined using UHPLC–MS to provide detailed profiles of the chemical differences between the three species and were compared to the PCA loadings. This study demonstrates a simple, fast, and easy analytical method that can be used to differentiate A. racemosa, Actaea podocarpa, and A. dahurica. - Highlights: • Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. • FIMS can discriminate between A. dahurica, A. podocarpa, and A. racemosa. • FIMS is a valuable screening tool for authentication of botanicals

  10. Chemometric profile of root extracts of Rhodiola imbricata Edgew. with hyphenated gas chromatography mass spectrometric technique.

    Directory of Open Access Journals (Sweden)

    Amol B Tayade

    Full Text Available Rhodiola imbricata Edgew. (Rose root or Arctic root or Golden root or Shrolo, belonging to the family Crassulaceae, is an important food crop and medicinal plant in the Indian trans-Himalayan cold desert. Chemometric profile of the n-hexane, chloroform, dichloroethane, ethyl acetate, methanol, and 60% ethanol root extracts of R. imbricata were performed by hyphenated gas chromatography mass spectrometry (GC/MS technique. GC/MS analysis was carried out using Thermo Finnigan PolarisQ Ion Trap GC/MS MS system comprising of an AS2000 liquid autosampler. Interpretation on mass spectrum of GC/MS was done using the NIST/EPA/NIH Mass Spectral Database, with NIST MS search program v.2.0g. Chemometric profile of root extracts revealed the presence of 63 phyto-chemotypes, among them, 1-pentacosanol; stigmast-5-en-3-ol, (3β,24S; 1-teracosanol; 1-henteracontanol; 17-pentatriacontene; 13-tetradecen-1-ol acetate; methyl tri-butyl ammonium chloride; bis(2-ethylhexyl phthalate; 7,8-dimethylbenzocyclooctene; ethyl linoleate; 3-methoxy-5-methylphenol; hexadecanoic acid; camphor; 1,3-dimethoxybenzene; thujone; 1,3-benzenediol, 5-pentadecyl; benzenemethanol, 3-hydroxy, 5-methoxy; cholest-4-ene-3,6-dione; dodecanoic acid, 3-hydroxy; octadecane, 1-chloro; ethanone, 1-(4-hydroxyphenyl; α-tocopherol; ascaridole; campesterol; 1-dotriacontane; heptadecane, 9-hexyl were found to be present in major amount. Eventually, in the present study we have found phytosterols, terpenoids, fatty acids, fatty acid esters, alkyl halides, phenols, alcohols, ethers, alkanes, and alkenes as the major group of phyto-chemotypes in the different root extracts of R. imbricata. All these compounds identified by GC/MS analysis were further investigated for their biological activities and it was found that they possess a diverse range of positive pharmacological actions. In future, isolation of individual phyto-chemotypes and subjecting them to biological activity will definitely prove fruitful

  11. Mass spectrometric methodology for the analysis of highly oxidized diterpenoid acids in Old Master paintings.

    Science.gov (United States)

    Berg; Boon; Pastorova; Spetter

    2000-04-01

    Diterpenoid resins from larch and pine trees and the corresponding fractions in a >100-year-old wax-resin adhesive and varnish and a 200-year-old resin/oil paint sample were analysed with by gas chromatography/mass spectrometry (GC/MS) using several off-line and on-line derivatization methods. The main resin compounds were highly oxidized abietic acids. Important products found are hydroxydehydroabietic acids (OH-DHAs), 7-oxoDHA, di-OH-DHAs and 15-OH-7-oxoDHA. The last two compounds have not been reported to occur in artworks before. Larixyl acetate, an important marker from larch resins, was found to be still present in high amounts in the adhesive. A large number of mass spectra of the different oxidation products and larixol and larixyl acetate are presented and their fragmentation behaviour under electron impact conditions is discussed. An index for the degree of oxidation (IDOX) of the abietic acids is presented as an indicator of the degree of oxidation of the matrix in which the resin is present. The IDOX was 0.10, 0.67, 0.81 and 0.76 for the fresh resins, the dark-aged adhesive, the aged varnish and the resin/oil paint, respectively (measured with pyrolysis (Py)-tetramethylammonium hydroxide (TMAH)-GC/MS). Py-TMAH-GC/MS and direct temperature-resolved mass spectrometry are reliable, valuable and fast techniques for the assessment of the presence and degree of oxidation of diterpenoid resins. Copyright 2000 John Wiley & Sons, Ltd. PMID:10797648

  12. Mass spectrometric analysis of selected radiolyzed amino acids in an astrochemical context

    International Nuclear Information System (INIS)

    A selection of amino acids, namely arginine, proline and tyrosine previously irradiated to 3.2 mega-Gray in the solid state and analyzed by differential scanning calorimetry (DSC) and optical rotatory dispersion (ORD) were analyzed in the present work by mass spectrometry with the purpose to identify the radiolysis products and validate the results obtained previously with DSC and ORD. The radiolysis of amino acids is a top-down approach of a research program designed to assess the radiolysis resistance of these molecules for 4.6 x 109 years once buried in primitive bodies of the Solar System. (author)

  13. In-gel digestion for mass spectrometric characterization of proteins and proteomes.

    Science.gov (United States)

    Shevchenko, Andrej; Tomas, Henrik; Havlis, Jan; Olsen, Jesper V; Mann, Matthias

    2006-01-01

    In-gel digestion of proteins isolated by gel electrophoresis is a cornerstone of mass spectrometry (MS)-driven proteomics. The 10-year-old recipe by Shevchenko et al. has been optimized to increase the speed and sensitivity of analysis. The protocol is for the in-gel digestion of both silver and Coomassie-stained protein spots or bands and can be followed by MALDI-MS or LC-MS/MS analysis to identify proteins at sensitivities better than a few femtomoles of protein starting material. PMID:17406544

  14. Pyrolysis-mass spectrometric prediction of liquefaction reactivity and structural analysis of coals

    Energy Technology Data Exchange (ETDEWEB)

    Durfee, S.L.; Voorhees, K.J.

    1985-10-01

    Forty-seven PSOC coals were pyrolyzed with eight replicates each in a Curie point pyrolysis mass spectrometer. This large data set was normalized and then analyzed using principal component analysis. From the reduced data set, equations were developed by using stepwise linear regression which modeled reactivity of the coal in tubing bombs and in the Gulf continuous flow reactor. Through the use of factor and loading spectra, structural components of the coal which were correlated with reactivity were identified. 33 references, 9 figures, 1 table.

  15. A mass spectrometric study of the vaporization of boron phosphate (BPO(4))

    Science.gov (United States)

    Lopatin; Semenov

    1999-01-01

    The vaporization behavior of boron phosphate has been studied by using Knudsen effusion mass spectrometry. The vapor over BPO(4) consists of B(2)O(3), P(4)O(10), PO(2), BPO(4) (platinum cell) and B(2)O(3), PO, PO(2), BPO(3), BPO(4) (molybdenum cell). Standard enthalpies of formation and atomization (kJ/mol) were derived for BPO(4) (g) (-1000 +/- 15 and 2863 +/- 16) and for BPO(3) (g) (-731 +/- 15 and 2347 +/- 16), respectively. Copyright 1999 John Wiley & Sons, Ltd.

  16. Nanodisc-based Co-immunoprecipitation for Mass Spectrometric Identification of Membrane-interacting Proteins

    DEFF Research Database (Denmark)

    Borch-Jensen, Jonas; Roepstorff, Peter; Møller-Jensen, Jakob

    2011-01-01

    interaction partners of the glycolipid ganglioside GM1 harbored by nanodiscs. Highly specific binding activity for nanodisc-GM1 immobilized on sensorchips was observed by surface plasmon resonance in culture media from enterotoxigenic Escherischia coli. To isolate the interaction partner(s) from...... enterotoxigenic Escherischia coli, GM1-nanodiscs were employed for co-immunoprecipitation. The B subunit of heat labile enterotoxin was identified as a specific interaction partner by mass spectrometry, thus demonstrating that nanodisc technology is useful for highly specific detection and identification of...

  17. New FORTRAN computer programs to acquire and process isotopic mass spectrometric data: Operator`s manual

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.H.; McKown, H.S.

    1993-09-01

    This TM is one of a pair that describes ORNL-developed software for acquisition and processing of isotope ratio mass spectral data. This TM is directed at the laboratory analyst. No technical knowledge of the programs and programming is required. It describes how to create and edit files, how to acquire and process data, and how to set up files to obtain the desired results. The aim of this TM is to serve as a utilitarian instruction manual, a {open_quotes}how to{close_quotes} approach rather than a {open_quotes}why?{close_quotes}

  18. GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS OF HIGH PURITY SULFUR HEXAFLUORIDE ENRICHED WITH 32S ISOTOPE

    OpenAIRE

    Krylov, V. A.; Sozin, A. Iu.; Chernova, O. Iu.

    2016-01-01

    The method of gas chromatography-mass spectrometry was used for the first time to investigate the impurity composition of high-purity sulfur hexafluoride enriched with 32S isotope. For the separation of impurities an adsorption capillary column GS-GasPro of 60 m ´ 0.32 mm with a modified silica gel and a column of 25 m × 0.26 mm, df = 0.25 microns with  a poly trimethylsilyl propyne (PTMSP) were used. It was shown that GS-GasPro column allowed separating the impurity substances with low molec...

  19. Determination of Metformin in Human Plasma by Liquid Chromatography-tandem Mass Spectrometric Assay

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; WANG Ying-wu; GU Jing-kai; WU Yi; WANG Yan

    2005-01-01

    @@ Introduction Metformin (1,1-dimethylbiguanide) (Fig. 1) is an oral anti-hyperglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus (type Ⅱ). Owing to its weight-decreasing and serum lipid-normalizing effects, it is especially recommended for obese patients[1,2] Various analytical methods have been described for the measurement of metformin in biological fluids, including gas chromatography(GC)[3-5], capillary electrophoresis (CE)[6] and HPLC[7~16]with UV detection[7-12,17] HPLC-Mass spectrometry (LC/APCIMS/MS ) offers an attractive alternative to HPLC[18].

  20. Mass spectrometric characterization of a pyrolytic radical source using femtosecond ionization

    Energy Technology Data Exchange (ETDEWEB)

    Frey, H.M.; Beaud, P.; Mischler, B.; Radi, P.P.; Tzannis, A.P.; Gerber, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Radicals play, as reactive species, an important role in the chemistry of combustion. In contrast to atmospheric flames where spectra are congested due to high vibrational and rotational excitation, experiments in the cold environment of a molecular beam (MB) yield clean spectra that can be easily attributed to one species by Resonantly Enhanced Multi Photon Ionization (REMP). A pyrolytic radical source has been set up. To characterize the efficiency of the source `soft` ionization with femto second pulses is applied which results in less fragmentation, simplifying the interpretation of the mass spectrum. (author) figs., tabs., refs.

  1. Characterization of spent nuclear fuels by an online combination of chromatographic and mass spectrometric techniques

    International Nuclear Information System (INIS)

    The determination of the burn-up is one of the essential parts in post-irradiation examinations on nuclear fuel samples. In the frame of national and international research programs the analysis of the isotopic vectors of uranium, plutonium, neodymium and some other fission products and actinides was carried out in the Hot lab of the Paul Scherrer Institute in the last years by using high-performance liquid chromatography coupled online with an inductively coupled plasma quadrupole mass spectrometer. In the meantime a multicollector ICP-MS, suitable for high precision isotope ratio measurements, was installed within the Hot lab and has been used now in combination with a chromatographic separation system for the first time for burn-up determinations of nuclear fuel samples. The results of these investigations, a comparison of both methods with the classical technique for burn-up analyses (thermal ionization mass spectrometry), the advantages and limitations of the methods and the accuracy and precision of this type of analyses are presented in the paper. (author)

  2. Thermogravimetric-Mass Spectrometric Study of the Pyrolysis Behavior of PVC

    Institute of Scientific and Technical Information of China (English)

    SUN Qing-lei; SHI Xin-gang; LIN Yun-liang; ZHU He; WANG Xiao; CHENG Chuan-ge; LIU Jian-hua

    2007-01-01

    The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000 ℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412 ℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HCl, C6H6, light hydrocarbon and chlorine-containing gases. The evolution curves showed that HCl, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416 ℃. This is consistent with the fact that the weight loss curves also peak at about 412 ℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions: dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.

  3. Rapid mass-spectrometric determination of boron isotopic distribution in boron carbide.

    Science.gov (United States)

    Rein, J E; Abernathey, R M

    1972-07-01

    Boron isotopic ratios are measured in boron carbide by thermionic ionization mass spectrometry with no prior chemical separation. A powder blend of boron carbide and sodium hydroxide is prepared, a small portion is transferred to a tantalum filament, the filament is heated to produce sodium borate, and the filament is transferred to the mass spectrometer where the(11)B/(10)B ratio is measured, using the Na(2)BO(2)(+) ion. Variables investigated for their effect on preferential volatilization of (10)B include the sodium hydroxide-boron carbide ratio and the temperature and duration of filament heating. A series of boron carbide pellets containing natural boron, of the type proposed for the control rods of the Fast Flux Test Facility reactor, were analysed with an apparently unbiased result of 4.0560 for the (11)B/(10)B ratio (standard deviation 0.0087). The pellets contained over 3% metal impurities typically found in this material. Time of analysis is 45 min per sample, with one analyst. PMID:18961131

  4. Rapid mass-spectrometric determination of boron isotopic distribution in boron carbide.

    Science.gov (United States)

    Rein, J E; Abernathey, R M

    1972-07-01

    Boron isotopic ratios are measured in boron carbide by thermionic ionization mass spectrometry with no prior chemical separation. A powder blend of boron carbide and sodium hydroxide is prepared, a small portion is transferred to a tantalum filament, the filament is heated to produce sodium borate, and the filament is transferred to the mass spectrometer where the(11)B/(10)B ratio is measured, using the Na(2)BO(2)(+) ion. Variables investigated for their effect on preferential volatilization of (10)B include the sodium hydroxide-boron carbide ratio and the temperature and duration of filament heating. A series of boron carbide pellets containing natural boron, of the type proposed for the control rods of the Fast Flux Test Facility reactor, were analysed with an apparently unbiased result of 4.0560 for the (11)B/(10)B ratio (standard deviation 0.0087). The pellets contained over 3% metal impurities typically found in this material. Time of analysis is 45 min per sample, with one analyst.

  5. Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    International Nuclear Information System (INIS)

    The standard covers analytical procedures to determine compliance of nuclear-grade uranyl nitrate solution to specifications. The following methods are described in detail: uranium by ferrous sulfate reduction-potassium dichromate titrimetry and by ignition gravimetry; specific gravity by pycnometry; free acid by oxalate complexation; thorium by the Arsenazo(III) (photometric) method; chromium by the diphenylcarbazide (photometric) method; molybdenum by the thiocyanate (photometric) method; halogens separation by steam distillation; fluorine by specific ion electrode; halogen distillate analysis: chloride, bromide and iodide by amperometric microtitrimetry; bromine by the fluorescein (photometric) method; sulfate sulfur by (photometric) turbidimetry; phosphorus by the molybdenum blue (photometric) method; silicon by the molybdenum blue (photometric) method; carbon by persulfate oxidation-acid titrimetry; nonvolatile impurities by spectrography; volatile impurities by rotating-disk spark spectrography; boron by emission spectrography; impurity elements by spark source mass spectrography; isotopic composition by multiple filament surface-ionization mass spectrometry; uranium-232 by alpha spectrometry; total alpha activity by direct alpha counting; fission product activity by beta and gamma counting; entrained organic matter by infrared spectrophotometry

  6. A mass spectrometric investigation of the vaporisation behaviour in the (U + Pu + O) system

    International Nuclear Information System (INIS)

    Highlights: • Vapour pressure measurements performed at high temperatures on (U, Pu) oxide samples. • Experimental facility consisted of a Knudsen cell coupled with a mass spectrometer. • Partial pressures of gaseous species were assessed from ionisation efficiency curves. • Vapour pressure was calculated using a thermochemical model for the ternary system. -- Abstract: The vaporisation behaviour of (U, Pu)O2 mixed oxides (Pu/M = 0.25, 0.50 and 0.75, with M = U + Pu) was studied by means of mass spectrometry. Hyperstoichiometric samples were heated in a Knudsen cell up to T = 2300 K. The evolution of the uranium and plutonium bearing gaseous species was studied as a function of time in order to evaluate the congruent vapour composition. Ionisation efficiency measurements were performed and the partial pressures of the gaseous species involved in the vaporisation process were determined. The vapour pressure has also been calculated using a thermochemical model for the (U + Pu + O) system. A quasi congruent composition with respect to the O/M ratio has been assumed, in agreement with the experiments. Nevertheless, the evaluation of all the experimental and calculated results shows that a total congruent composition exists for a single composition of the mixed oxide (MOX) samples with a Pu/M content slightly lower than 0.50. A good agreement is obtained between the calculated and experimental vapour pressure data, as well as the quasi congruent vaporisation compositions

  7. Mass spectrometric studies of the vapour phase in the (Pu + O) system

    International Nuclear Information System (INIS)

    Highlights: → Vapour pressure measurements performed at high temperatures on PuO2-x samples. → Experimental facility consisted of a Knudsen cell coupled with a mass spectrometer. → Partial pressures of gaseous species were assessed from ionisation efficiency curves. → (Pu + O) system was studied for stoichiometry corresponding to O/M from 1.5 to 2.0. - Abstract: Vapour pressure measurements at high temperatures have been performed on plutonium oxide samples using a Knudsen cell coupled with a mass spectrometer. Different experimental conditions were applied for the derivation of the solid-gas phase relations for three composition in the Pu-O phase diagram: the (Pu2O3-PuO2-x) two-phase domain, the congruent vapourisation composition and near stoichiometric PuO2.00. The partial pressures of the gaseous species PuO2, PuO, and Pu were assessed from ionisation efficiency curves recorded at constant temperature. The vapour pressure results for different phase fields were discussed together with all the available literature data.

  8. Engineering cell-compatible paper chips for cell culturing, drug screening, and mass spectrometric sensing.

    Science.gov (United States)

    Chen, Qiushui; He, Ziyi; Liu, Wu; Lin, Xuexia; Wu, Jing; Li, Haifang; Lin, Jin-Ming

    2015-10-28

    Paper-supported cell culture is an unprecedented development for advanced bioassays. This study reports a strategy for in vitro engineering of cell-compatible paper chips that allow for adherent cell culture, quantitative assessment of drug efficiency, and label-free sensing of intracellular molecules via paper spray mass spectrometry. The polycarbonate paper is employed as an excellent alternative bioscaffold for cell distribution, adhesion, and growth, as well as allowing for fluorescence imaging without light scattering. The cell-cultured paper chips are thus amenable to fabricate 3D tissue construction and cocultures by flexible deformation, stacks and assembly by layers of cells. As a result, the successful development of cell-compatible paper chips subsequently offers a uniquely flexible approach for in situ sensing of live cell components by paper spray mass spectrometry, allowing profiling the cellular lipids and quantitative measurement of drug metabolism with minimum sample pretreatment. Consequently, the developed paper chips for adherent cell culture are inexpensive for one-time use, compatible with high throughputs, and amenable to label-free and rapid analysis.

  9. Mass spectrometric characterization of elements and molecules in cell cultures and tissues

    Science.gov (United States)

    Arlinghaus, H. F.; Kriegeskotte, C.; Fartmann, M.; Wittig, A.; Sauerwein, W.; Lipinsky, D.

    2006-07-01

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (laser-SNMS) have been used to image and quantify targeted compounds, intrinsic elements and molecules with subcellular resolution in single cells of both cell cultures and tissues. Special preparation procedures for analyzing cell cultures and tissue materials were developed. Cancer cells type MeWo, incubated with boronated compounds, were sandwiched between two substrates, cryofixed, freeze-fractured and freeze-dried. Also, after injection with boronated compounds, different types of mouse tissues were extracted, prepared on a special specimen carrier and plunged with high velocity into LN 2-cooled propane for cryofixation. After trimming, these tissue blocks were freeze-dried. The measurements of the K/Na ratio demonstrated that for both cell cultures and tissue materials the special preparation techniques used were appropriate for preserving the chemical and structural integrity of the living cell. The boron images show inter- and intracellular boron signals with different intensities. Molecular images show distinct features partly correlated with the cell structure. A comparison between laser-SNMS and ToF-SIMS showed that especially laser-SNMS is particularly well-suited for identifying specific cell structures and imaging ultratrace element concentrations in tissues.

  10. Mass spectrometric characterization of elements and molecules in cell cultures and tissues

    Energy Technology Data Exchange (ETDEWEB)

    Arlinghaus, H.F. [Physikalisches Institut, Universitaet Muenster, Wilhelm-Klemm-Str. 10, D-48149 Muenster (Germany)]. E-mail: arlinghaus@uni-muenster.de; Kriegeskotte, C. [Physikalisches Institut, Universitaet Muenster, Wilhelm-Klemm-Str. 10, D-48149 Muenster (Germany); Fartmann, M. [Physikalisches Institut, Universitaet Muenster, Wilhelm-Klemm-Str. 10, D-48149 Muenster (Germany); Wittig, A. [Strahlenklinik, Universitaetsklinikum Essen, D-45122 Essen (Germany); Sauerwein, W. [Strahlenklinik, Universitaetsklinikum Essen, D-45122 Essen (Germany); Lipinsky, D. [Physikalisches Institut, Universitaet Muenster, Wilhelm-Klemm-Str. 10, D-48149 Muenster (Germany)

    2006-07-30

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and laser post-ionization secondary neutral mass spectrometry (laser-SNMS) have been used to image and quantify targeted compounds, intrinsic elements and molecules with subcellular resolution in single cells of both cell cultures and tissues. Special preparation procedures for analyzing cell cultures and tissue materials were developed. Cancer cells type MeWo, incubated with boronated compounds, were sandwiched between two substrates, cryofixed, freeze-fractured and freeze-dried. Also, after injection with boronated compounds, different types of mouse tissues were extracted, prepared on a special specimen carrier and plunged with high velocity into LN{sub 2}-cooled propane for cryofixation. After trimming, these tissue blocks were freeze-dried. The measurements of the K/Na ratio demonstrated that for both cell cultures and tissue materials the special preparation techniques used were appropriate for preserving the chemical and structural integrity of the living cell. The boron images show inter- and intracellular boron signals with different intensities. Molecular images show distinct features partly correlated with the cell structure. A comparison between laser-SNMS and ToF-SIMS showed that especially laser-SNMS is particularly well-suited for identifying specific cell structures and imaging ultratrace element concentrations in tissues.

  11. Cryogenic micro-calorimeters for mass spectrometric identification of neutral molecules and molecular fragments

    CERN Document Server

    Novotný, O; Enss, C; Fleischmann, A; Gamer, L; Hengstler, D; Kempf, S; Krantz, C; Pabinger, A; Pies, C; Savin, D W; Schwalm, D; Wolf, A

    2015-01-01

    We have systematically investigated the energy resolution of a magnetic micro-calorimeter (MMC) for atomic and molecular projectiles at impact energies ranging from $E\\approx13$ to 150~keV. For atoms we obtained absolute energy resolutions down to $\\Delta E \\approx 120$~eV and relative energy resolutions down to $\\Delta E/E\\approx10^{-3}$. We also studied in detail the MMC energy-response function to molecular projectiles of up to mass 56~u. We have demonstrated the capability of identifying neutral fragmentation products of these molecules by calorimetric mass spectrometry. We have modeled the MMC energy-response function for molecular projectiles and conclude that backscattering is the dominant source of the energy spread at the impact energies investigated. We have successfully demonstrated the use of a detector absorber coating to suppress such spreads. We briefly outline the use of MMC detectors in experiments on gas-phase collision reactions with neutral products. Our findings are of general interest fo...

  12. Interpretation of organic components from positive matrix factorization of aerosol mass spectrometric data

    Directory of Open Access Journals (Sweden)

    I. M. Ulbrich

    2008-04-01

    Full Text Available The organic aerosol (OA dataset from an Aerodyne Aerosol Mass Spectrometer (Q-AMS collected at the Pittsburgh Air Quality Study in September 2002 was analyzed for components with Positive Matrix Factorization (PMF. Three components – hydrocarbon-like organic aerosol OA (HOA, a highly-oxygenated OA (OOA-I that correlates well with sulfate, and a less-oxygenated, semi-volatile OA (OOA-II that correlates well with nitrate and chloride – are identified and interpreted as primary combustion emissions, aged SOA, and semivolatile, less aged SOA, respectively. The complexity of interpreting the PMF solutions of unit mass resolution (UMR AMS data is illustrated by a detailed analysis of the solutions as a function of number of components and rotational state. A public database of AMS spectra has been created to aid this type of analysis. A sensitivity analysis with realistic synthetic data is also used to characterize the behavior of PMF for choosing the best number of factors, rotations of non-unique solutions, and the retrievability of more (or less correlated factors. The ambient and synthetic data indicate that the variation of the PMF quality of fit parameter (Q, a normalized chi-squared metric vs. number of factors in the solution is useful to identify the minimum number of factors, but more detailed analysis and interpretation is needed to choose the best number of factors. The maximum value of the rotational matrix is not useful for determining the best number of factors. In synthetic datasets, factors are "split" into two or more components when solving for more factors than were used in the input. Elements of the "splitting" behavior are observed in solutions of real datasets with several factors. Significant structure remains in the residual of the real dataset after physically-meaningful factors have been assigned and an unrealistic number of factors would be required to explain the remaining variance. This residual structure appears to

  13. Comparative Studies on Mass Spectrometric Fragmentation of Linear Chiral Secondary Alcohols (R) -1-(4-Alkylphenyl) and (R) -1-(4-Alkoxyphenyl/Alkylthiophenyl) Alcohols

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Mass spectrometric behaviour of (R)-1-(4-alkylphenyl) alcohols, 1-(4-alkoxylphenyl) alcohols, and 1-(4-alkylthiophenyl) alcohols were studied with the aid of mass-analyzed ion kinetic energy spectrometry under electron impact ionization. All the title compounds show a tendency to eliminate a water molecule to form alkene ions and undergo an a-cleavage to produce protonated aldehyde ions by the loss of alkyl radicals. Except these two common fragment ions, they also show some different fragmentations due to with or without oxy/thioether-linkage.

  14. Nasal absorption studies of granisetron in rats using a validated high-performance liquid chromatographic method with mass spectrometric detection.

    Science.gov (United States)

    Woo, Jong Soo

    2007-06-01

    Granisetron is a selective 5-HT3 receptor antagonist that is used therapeutically for the prevention of vomiting and nausea associated with emetogenic cancer chemotherapy. Although forms of the drug are commercially available for intravenous and oral dosage, there is a need for intranasal delivery formulations in specific patient populations in which the use of these dosage forms may be unfeasible and/or inconvenient. A rapid and specific high-performance liq uid chromatography method with mass spectrometric detection (LC-MS) was developed and validated for the analysis of granisetron in plasma after nasal administration in rats. Granisetron was separated in a reverse-phase C-18 column without interference from other components of plasma. This method involves a rapid assay for the determination of granisetron in a small volume of plasma with a run time of 12 min using ondansetron as an internal standard. Data were acquired in the electrospray ionization (ESI) mode with positive ion detection and application of single ion recording (SIR). Granisetron and ondansetron were detected at m/z values of 313.2 and 294.2, respectively. The method described was found to be suitable for the analysis of all samples collected during preclinical pharmacokinetic investigations of granisetron in rats after nasal administration. To date, the first pharmacokinetic study after intranasal administration of granisetron was performed and some pharmacokinetic parameters were presented in this paper. Granisetron was found to be well absorbed through nasal route and the bioavailability of this drug following nasal administration was comparable with that of intravenous administration. PMID:17679558

  15. Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions

    International Nuclear Information System (INIS)

    These analytical procedures are designed to show whether a given material meets the purchaser's specifications as to plutonium content, effective fissile content, and impurity content. The following procedures are described in detail: plutonium by controlled-potential coulometry; plutonium by amperometric titration with iron(II); free acid by titration in an oxalate solution; free acid by iodate precipitation-potentiometric titration method; uranium by Arsenazo I spectrophotometric method; thorium by thorin spectrophotometric method; iron by 1,10-phenanthroline spectrophotometric method; chloride by thiocyanate spectrophotometric method; fluoride by distillation-spectrophotometric method; sulfate by barium sulfate turbidimetric method; isotopic composition by mass spectrometry; americium-241 by extraction and gamma counting; americium-241 by gamma counting; gamma-emitting fission products, uranium, and thorium by gamma-ray spectroscopy; rare earths by copper spark spectrochemical method; tungsten, niobium (columbium), and tantalum by spectrochemical method; simple preparation by spectrographic analysis for general impurities

  16. Laser R2PI spectroscopic and mass spectrometric studies of chiral neurotransmitters

    Science.gov (United States)

    Giardini, A.; Marotta, V.; Paladini, A.; Piccirillo, S.; Rondino, F.; Satta, M.; Speranza, M.

    2007-07-01

    One color, mass selected resonant two-photon ionization (1cR2PI) spectra of supersonically expanded bare neurotransmitter, (1 S,2 S)-(+)- N-methyl pseudoephedrine (MPE), and its complexes with chiral and achiral molecules have been investigated. The excitation spectrum of bare MPE has been analyzed and discussed on the basis of theoretical predictions at the B3LYP/6-31G** level of theory. The results allowed to get information on the possible conformers of MPE molecule and on the intermolecular forces on its cluster formed with a variety of solvent molecules, including chiral alcohols, lactates and water. Further information on intermolecular interactions have been obtained with ESI-CID-MS 2 technique, applied to chiral biomolecules linked through a metal ion to the neurotransmitter. The experimental results are compared with theoretical predictions.

  17. [Mass Spectrometric Methods for Colorative Mechanism Analysis of Yaozhou Porcelain Glaze].

    Science.gov (United States)

    Xiao, Yuan-fang; He, Miao-hong; Zhang, Shu-di; Hang, Wei

    2015-09-01

    An in-house-built femtosecond laser ionization time-of-flight mass spectrometry (fs-LI-TOFMS) has been applied to the multi-elemental analysis of porcelain glaze from Yaozhou kiln. The samples are selected representing products of different dynasties, including Tang, Five, Song, Jin, and Ming Dynasty. For exploring the colorative mechanism of Yaozhou porcelain through the elemental analysis of the glaze, the effects of all potential coloring elements, especially transition elements, were considered. There was a speculation that the typical Co-Cr-Fe-Mn recipe was used in the fabrication of Yaozhou black glaze; the low content of Fe and high content of Ni resulted in the porcelain of white glaze; an increase content of P could lead the porcelain to be yellow-glazed. Undoubtedly, this research is an important supplement to the study of the colorative mechanism of the Yaozhou porcelain system. PMID:26669145

  18. Mass spectrometric investigation into thermal decomposition of double hafnium and ammonium sulfate

    International Nuclear Information System (INIS)

    The method of pyrolytic mass spectrometry has been used to investigate thermal decomposition doUble hafnium ammonium sulfate of the (Nr4)4Hf(SO4)4X4H2O composition during heating from 20 to 800 deg. In volatile destruction products the following ions are found: H2O+, NH3+, SO+, SO2+, O2+, H2S+, N2+, SO3+ ion is practically absent. Removal of crystallization water occurs in the 85-285 deg range, that of ammonium and sulfur oxides - at 300-775 deg. Higher than 300 deg the ratios of intensities of peaks of SO2+:SO+:O2+ ions do not exceed those standard for SO2, which proves a deeper destruction of sUlfUr dioxide under given conditions

  19. On-chip electro membrane extraction with online ultraviolet and mass spectrometric detection

    DEFF Research Database (Denmark)

    Petersen, Nickolaj Jacob; Foss, Sunniva Taule; Jensen, Henrik;

    2011-01-01

    Electro membrane extraction was demonstrated in a microfluidic device. The device was composed of a 25 μm thick porous polypropylene membrane bonded between two poly(methyl methacrylate) (PMMA) substrates, each having 50 μm deep channel structures facing the membrane. The supported liquid membrane...... (SLM) consisted of 2-nitrophenyl octyl ether (NPOE) immobilized in the pores of the membrane. The driving force for the extraction was a 15 V direct current (DC) electrical potential applied across the SLM. Samples containing the basic drugs pethidine, nortriptyline, methadone, haloperidol, loperamide......L/min, enrichment factors exceeding 75 were obtained during 12 min of operation from a total sample volume of only 108 μL. The on-chip electro membrane system was coupled online to electrospray ionization mass spectrometry and used to monitor online and real-time metabolism of amitriptyline by rat liver microsomes...

  20. Gas chromatographic and mass spectrometric analysis of conjugated steroids in urine

    Indian Academy of Sciences (India)

    Jong Man Yoon; Kyung Ho Lee

    2001-12-01

    This study was carried out qualitatively and quantitatively to investigate the presence and the concentrations of anabolic steroids in urine collected from orally administered humans. Microanalysis of conjugated steroids by gas chromatography and mass spectrometry (GC/MS) has been carried out. Following oral administration three major metabolites of anabolic steroid drugs have been detected and partially characterized. The six steroids can be analysed at the same time in 17 min. The lower detection limit was 10 ng/ml in 5 ml of urine. The conjugated steroids from urine were centrifuged to 2,430 for 10 min, the supernatant solution passed through Amberlite XAD-2 column and the steroids eluted fraction esterified by using MSTFA and TMSI. The rate of metabolism and urinary excretion seem to be reasonably fast.

  1. Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis

    Science.gov (United States)

    Ball, J.W.; Bassett, R.L.

    2000-01-01

    A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

  2. Sensitive and specific liquid chromatographic-tandem mass spectrometric assay for barnidipine in human plasma.

    Science.gov (United States)

    Pawula, M; Watson, D; Teramura, T; Watanabe, T; Higuchi, S; Cheng, K N

    1998-11-20

    A sensitive and specific LC-MS-MS assay has been developed and validated for barnidipine (1-benzyl-3-pyrrolidinyl)methyl-2,6-dimethyl-4(m-nitrophenyl)-1,4-dihydr opyridine-3,5-dicarboxylate). The assay involves a simple and rapid solid-phase extraction procedure. Sample analysis was on a Spherisorb S3ODS2 100 mmX2 mm I.D. column, with a Finnigan TSQ 7000 mass spectrometer, using an electrospray interface and selective reaction monitoring (SRM). The intra- and inter-day precision and accuracy, determined as the coefficient of variation and relative error, respectively, were 11.8% or less. The limit of quantitation was 0.03 ng/ml, and the calibration was linear between 0.03 and 3.0 ng/ml. The method has been used successfully for the measurement of over two thousand human plasma samples from pharmacokinetic clinical trials. PMID:9869371

  3. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    Science.gov (United States)

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol. PMID:26112364

  4. Expression, purification and mass spectrometric analysis of LIM mineralization protein-1 in human lung epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Sreedhara Sangadala; Louisa Titus; Scott D. Boden

    2008-01-01

    LIM mineralization protein-1 (LMP-1) is a novel osteoin ductive protein that has been cloned and shown to induce bone formation both in vitro and in vivo. Detection and evaluation of the possible presence of carbohydrate structures in LMP-1 is an important regulatory consideration for the therapeutic use of recombinantly expressed protein. The sequence of LMP-1 contains a highly conserved N-terminal PDZ domain and three C-terminal LIM domains. The sequence analysis of LMP-I predicts two potential N-glycosylation sites and several O-glycosylation sites. Here, we report the cloning and overexpression of LMP.1 in human lung carcinoma(A549) cells. Even though our group already reported the sequence of LMP-1 cDNA, we undertook this work to clarify whether or not the overexpressed protein undergoes any glycosylation in vivo. The expressed full-length recombinant protein was purified and subjected to chemical analysis and internal sequencing. The absence of any hexosamines (Nacetyl glucosamine or N-acetyl galactosamine) in chemical composition analysis of LMP.I protein revealed that there is little or no post-translational glycosylation of the LMP-1 polypeptide in lung carcinoma cells (A549). We performed in-gel trypsin digestion on purified LMP-I, and the resulting peptide digests were analyzed further using matrix.assisted laser desorption and ionization mass spectrometry for peptide mass finger printing, which produced several exact matches with the corresponding LMP-1 peptides. Separation by high performance liquid chromatography and purification of the desired peptides followed by N-terminal sequencing resulted in many exact LMP-1 matches for several purified peptides, thus establishing the identity of the purified protein as LMP-1.

  5. Honeybee Venom Proteome Profile of Queens and Winter Bees as Determined by a Mass Spectrometric Approach

    Directory of Open Access Journals (Sweden)

    Ellen L. Danneels

    2015-10-01

    Full Text Available Venoms of invertebrates contain an enormous diversity of proteins, peptides, and other classes of substances. Insect venoms are characterized by a large interspecific variation resulting in extended lists of venom compounds. The venom composition of several hymenopterans also shows different intraspecific variation. For instance, venom from different honeybee castes, more specifically queens and workers, shows quantitative and qualitative variation, while the environment, like seasonal changes, also proves to be an important factor. The present study aimed at an in-depth analysis of the intraspecific variation in the honeybee venom proteome. In summer workers, the recent list of venom proteins resulted from merging combinatorial peptide ligand library sample pretreatment and targeted tandem mass spectrometry realized with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS/MS. Now, the same technique was used to determine the venom proteome of queens and winter bees, enabling us to compare it with that of summer bees. In total, 34 putative venom toxins were found, of which two were never described in honeybee venoms before. Venom from winter workers did not contain toxins that were not present in queens or summer workers, while winter worker venom lacked the allergen Api m 12, also known as vitellogenin. Venom from queen bees, on the other hand, was lacking six of the 34 venom toxins compared to worker bees, while it contained two new venom toxins, in particularly serine proteinase stubble and antithrombin-III. Although people are hardly stung by honeybees during winter or by queen bees, these newly identified toxins should be taken into account in the characterization of a putative allergic response against Apis mellifera stings.

  6. Honeybee venom proteome profile of queens and winter bees as determined by a mass spectrometric approach.

    Science.gov (United States)

    Danneels, Ellen L; Van Vaerenbergh, Matthias; Debyser, Griet; Devreese, Bart; de Graaf, Dirk C

    2015-11-01

    Venoms of invertebrates contain an enormous diversity of proteins, peptides, and other classes of substances. Insect venoms are characterized by a large interspecific variation resulting in extended lists of venom compounds. The venom composition of several hymenopterans also shows different intraspecific variation. For instance, venom from different honeybee castes, more specifically queens and workers, shows quantitative and qualitative variation, while the environment, like seasonal changes, also proves to be an important factor. The present study aimed at an in-depth analysis of the intraspecific variation in the honeybee venom proteome. In summer workers, the recent list of venom proteins resulted from merging combinatorial peptide ligand library sample pretreatment and targeted tandem mass spectrometry realized with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS/MS). Now, the same technique was used to determine the venom proteome of queens and winter bees, enabling us to compare it with that of summer bees. In total, 34 putative venom toxins were found, of which two were never described in honeybee venoms before. Venom from winter workers did not contain toxins that were not present in queens or summer workers, while winter worker venom lacked the allergen Api m 12, also known as vitellogenin. Venom from queen bees, on the other hand, was lacking six of the 34 venom toxins compared to worker bees, while it contained two new venom toxins, in particularly serine proteinase stubble and antithrombin-III. Although people are hardly stung by honeybees during winter or by queen bees, these newly identified toxins should be taken into account in the characterization of a putative allergic response against Apis mellifera stings. PMID:26529016

  7. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    Science.gov (United States)

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol.

  8. Complexation of trace organic contaminants with fractionated dissolved organic matter: implications for mass spectrometric quantification.

    Science.gov (United States)

    Ruiz, Selene Hernandez; Wickramasekara, Samanthi; Abrell, Leif; Gao, Xiaodong; Chefetz, Benny; Chorover, Jon

    2013-04-01

    Interaction with aqueous phase dissolved organic matter (DOM) can alter the fate of trace organic contaminants of emerging concern once they enter the water cycle. In order to probe possible DOM binding mechanisms and their consequences for contaminant detection and quantification in natural waters, a set of laboratory experiments was conducted with aqueous solutions containing various operationally-defined "hydrophilic" and "hydrophobic" freshwater DOM fractions isolated by resin adsorption techniques from reference Suwannee River natural organic matter (SROM). Per unit mass of SROM carbon, hydrophobic acids (HoA) comprised the largest C fraction (0.63±0.029), followed by hydrophilic-neutrals (HiN, 0.11±0.01) and acids (HiA, 0.09±0.017). Aqueous solutions comprising 8mgL(-1) DOC of each SROM fraction were spiked with a concentration range (10-1000μgL(-1)) of bisphenol A (BPA), carbamazepine (CBZ), or ibuprofen (IBU) as model target compounds in 24mM NH4HCO3 background electrolyte at pH 7.4. Contaminant interaction with the SROM fractions was probed using fluorescence spectroscopy, and effects on quantitative analysis of the target compounds were measured using direct aqueous-injection liquid chromatography tandem mass spectrometry (LC-MS/MS). Total quenching was greater for the hydrophilic fractions of SROM and associations were principally with protein-like and fulvic acid-like constituents. Whereas LC-MS/MS recoveries indicated relatively weak interactions with most SROM factions, an important exception was the HiA fraction, which diminished recovery of CBZ and IBU by ca. 30% and 70%, respectively, indicating relatively strong molecular interactions. PMID:23276460

  9. Determination of long-lived radionuclides at ultratrace level using advanced mass spectrometric techniques

    International Nuclear Information System (INIS)

    Determination of long-lived radionuclides at sub-fg concentration level is a challenging task in analytical chemistry. Inductively coupled plasma mass spectrometry (ICP-MS) with its ability to provide the sensitive and fast multielemental analysis is one of the most suitable method for the measurements of long lived radionuclides in the trace and ultra trace concentration range. In present the Ph.D. study a variety of procedures have been developed permitting the sub fg ml-1 determination of long-lived radionuclides (e.g. U, Th, Pu) as well as 226Ra (T1/2 = 1600 y) and 90Sr (T1/2= 28.1 y) in different samples. In order to avoid isobaric interferences, to increase the sensitivity, precision and accuracy of the methods the application of different techniques: pre-concentration of the sample, off-line separation on the crown resin, measurements under cold plasma conditions, using microconcentric nebulizers (e.g DIHEN, DS-5) or the application of LA-ICP-MS for sample introduction have been studied. The limits of detection for different radionuclides was significantly improved in comparison to the ones reported in the literature, and, depending on the method applied, was varied from 10-15 to 10-18 g ml-1 concentration range. In addition to the analysis of long lived radionuclides, some other elements, that can present potential interest to the analyzed sample, were measured within the framework of the present study. Laser ablation inductively coupled plasma mass spectrometry (LAICP- MS) was used to produce images of element distribution in 20μm m thin sections of human brain tissue. The sample surface was scanned (raster area ∝80 mm2) with a focused laser beam (wavelength 213 nm, diameter of laser crater 50μm, and laser power density 3x109 W cm-2) in a cooled laser ablation chamber developed for these measurements. Cross sections of human brain samples - hippocampus as well as brain tissues infected and non-infected with Glioblastoma Multiforme (tumor cells) were

  10. Calibration of Dissolved Noble Gas Mass Spectrometric Measurements by an Air-Water Equilibration System

    Science.gov (United States)

    Hillegonds, Darren; Matsumoto, Takuya; Jaklitsch, Manfred; Han, Liang-Feng; Klaus, Philipp; Wassenaar, Leonard; Aggarwal, Pradeep

    2013-04-01

    Precise measurements by mass spectrometry of dissolved noble gases (He, Ar, Ne, Kr, Xe) in water samples require careful calibration against laboratory standards with known concentrations. Currently, air pipettes are used for day-to-day calibrations, making estimation of overall analytical uncertainties for dissolved noble gas measurements in water difficult. Air equilibrated water (AEW) is often used as a matrix-equivalent laboratory standard for dissolved gases in groundwater, because of the well-known and constant fractions of noble gases in the atmosphere. AEW standards, however, are only useful if the temperature and pressure of the gas-water equilibrium can be controlled and measured precisely (i.e., to better than 0.5%); contamination and partial sample degassing must also be prevented during sampling. Here we present the details of a new custom air-water equilibration system which consists of an insulated 600 liter tank filled with deionized water, held isothermally at a precise target temperature (water in the tank are monitored continually, as are atmospheric pressure and air temperature in the laboratory. Different noble gas concentration standards can be reliably produced by accurately controlling the water temperature of the equilibration system. Equilibration characteristics and reproducibility of this system for production of copper tubes containing known amounts of noble gases will be presented.

  11. Mass spectrometric study of the release of volatile fission products from irradiated LWR fuel

    International Nuclear Information System (INIS)

    The objective of these studies is to experimentally determine the chemical form and the rate of release of volatile fission product species from defected irradiated LWR reactor fuel pins. After release from the defected fuel pin the gaseous species immediately enters the ionizer of a quadrupole mass spectrometer thus ensuring that their chemical form is not likely to be changed prior to identification and measurement. These studies differ from prior studies in that: (1) the chemical form of the volatile fission products will be determined; and (2) the detection and measurement method does not depend on the radioactivity of the fission product element. Information on the chemical form of the released fission product species will enable a more accurate description of their transport and reaction in the primary system. These studies are also expected to yield information on the reaction of fission products after release from the fuel oxide with the zircaloy cladding. The results of these studies are expected to increase the understanding of the first step in the release of fission products by irradiated fuel and therefore help in the accurate prediction of source terms

  12. Chemical, mass spectrometric, spectrochemical, nuclear and radiochemical analysis of nuclear-grade plutonium metal

    International Nuclear Information System (INIS)

    These analytical procedures are designed to show whether a given material meets the purchaser's specifications as to plutonium content, effective fissile content, and impurity content. The following procedures are described in detail: dissolution procedure; plutonium by controlled-potential coulometry; plutonium by amperometric titration with iron(II); plutonium by ceric sulfate titration method; uranium by Arsenazo I spectrophotometric method; thorium by thorin spectrophotometric method; iron by 1,10-phenanthroline spectrophotometric method; iron by 2,2'-bipyridyl spectrophotometric method; chloride by the thiocyanate spectrophotometric method; fluoride by distillation-spectrophotometric method; nitrogen by distillation-Nessler reagent spectrophotometric method; carbon by the direct combustion-thermal conductivity method; sulfur by distillation-spectrophotometric method; isotopic composition by mass spectrometry; Americium-241 by extraction and gamma counting; Americium-241 by gamma counting; gamma-emitting fission products, uranium, and thorium by gamma-ray spectroscopy; rare earths by copper spark spectrochemical method; tungsten, niobium (columbium) and tantalum by spectrochemical method; sample preparation for spectrographic analysis for trace impurities

  13. Mass spectrometric studies of the complexing behaviour of actinide ions in solution

    International Nuclear Information System (INIS)

    As the long-term radiotoxicity of spent nuclear fuel is governed by Plutonium and the Minor Actinides, these elements are focussed on for investigations in the framework of safety assessment for nuclear waste repositories. To shed more light on the selectivity of the partitioning ligands BTP and BTBP towards the extraction of trivalent actinides, the complexes these ligands form with lanthanides in octanolic solution were characterized. The differences in the extraction efficiencies among the different lanthanides were traced back to the varying preferential formation of Ln(BTP)3 complexes, depending on the ionic radius of the lanthanides. Additionally it was shown that depending on the sterical demand of BTBP ligands nitrate anions coordinate in the first coordination shell of Eu(BTBP)2-complexes. As the behavior of Plutonium under geochemical conditions is of particular interest for the safety assessment of potential nuclear waste repositories, the second part of the thesis focuses on the hydrolysis and colloid formation behavior of aqueous Plutonium solutions. The solution species of Zirconium(IV) as analogue for Plutonium(IV) as well as of Uranium(VI) and Plutonium(VI) were characterized and quantified by means of electrospray ionization mass spectrometry. Moreover the colloid-induced reduction of Pu(V) to Pu(IV) and the subsequent formation of colloidal species was investigated.

  14. Competitive ion kinetics in direct mass spectrometric organic speciation. 1994 Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Sieck, L.W.

    1994-12-31

    The experimental work on the gas phase proton affinity (PA) scale, discussed in some detail in last year`s Progress Report, will be completed within the next few weeks. Basically this effort involves the development of a precise and accurate interlocking ladder of relative PA`s derived from the temperature dependence of proton transfer equilibria incorporating a variety of reactant pairs using the technique of pulsed high pressure mass spectrometry (NIST has the only US facility). The PA subset under investigation was expanded from the original list to cover the region between CH{sub 3}CHO and (CH{sub 3}){sub 2}CO, which spans a PA range of approximately 12 kcal/mol. More than 300 separate equilibrium measurements have been carried out to date over the temperature range 240--395 C. The thermochemical region under study creates a bridge between the so-called upper and lower PA scales, and includes two primary reference standards, CH{sub 3}CHO and i-C{sub 4}H{sub 8}, with PA`s independently defined elsewhere via photoionization techniques.

  15. Calibration of mass spectrometric measurements of gas phase reactions on steel surfaces

    Science.gov (United States)

    Falk, H.; Falk, M.; Wuttke, T.

    2015-03-01

    The sampling of the surface-near gas composition using a mass spectrometer (MS-Probe) is a valuable tool within a hot dip process simulator. Since reference samples with well characterized surface coverage are usually not available, steel samples can deliver quantifiable amounts of the process relevant species H2O, CO and H2 using the decarburization reaction with water vapor. Such "artificial calibration samples" (ACS) can be used for the calibration of the MS-Probe measurements. The carbon release rate, which is governed by the diffusion law, was determined by GDOES, since the diffusion coefficients of carbon in steel samples are usually not known. The measured carbon concentration profiles in the ACS after the thermal treatment confirmed the validity of the diffusion model described in this paper. The carbon bulk concentration > 100 ppm is sufficient for the use of a steel material as ACS. The experimental results reported in this paper reveal, that with the MS-Probe the LOQ of less than one monolayer of iron oxide can be achieved.

  16. Ultrafast High-Resolution Mass Spectrometric Finger Pore Imaging in Latent Finger Prints

    Science.gov (United States)

    Elsner, Christian; Abel, Bernd

    2014-11-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record `three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals.

  17. Vaporisation studies on tellurium dioxide: A Knudsen effusion mass spectrometric study

    Science.gov (United States)

    Lakshmi Narasimhan, T. S.; Balasubramanian, R.; Nalini, S.; Sai Baba, M.

    1997-08-01

    The vaporisation of TeO 2(s) was studied by Knudsen effusion mass spectrometry. The vapour phase was found to consist of (TeO 2) n(n = 1-3)(g), (TeO) n(g) (n = 1-3) and Te 2(g). The p- T relations of TeO 2(g), (TeO 2) 2(g) and (TeO 2) 3(g) were derived to be log( p/Pa) = (-13534 ± 78)/ T + (14.241 ± 0.09) (750-950 K), log( p/Pa) = (-14823 ± 212)/T + (14.373 ± 0.242) (825-950 K) and log( p/Pa) = (-19074 ± 540)/ T+ (17.337 ± 0.606) (850-921 K) respectively. From the partial pressures, Δ rH298.150 of nTeO 2(s) = (TeO 2) n(g) ( n = 1-3) were evaluated by second and third law methods. Also, enthalpy of the pressure independent reaction TeO 2(s) + TeO 2(g) = (TeO 2) 2(g) has been evaluated. Using the Δ fH 298.150 of TeO 2(s), Δ fH 298.150 of (Te0 2) n(g) ( n= 1-3) were calculated. The partial pressure and enthalpy data for (TeO 2) 3(g) have been obtained for the first time.

  18. Resonance ionization mass spectrometric analysis of thorium by external laser cavity enhancement techniques

    International Nuclear Information System (INIS)

    Over the last several years, extensive effort has been directed towards the demonstration of Resonance Ionization Mass Spectrometry (RIMS) as a generally-applicable isotopic analysis technique. The major problems in this task have been to achieve a high overall ionization efficiency as well as good sample utilization. Several aspects of these problems are apparent in the choice of the excitation and ionization sources for the selective RIMS process. Pulsed lasers have typically had low repetition rates, poor spectral and temporal behavior, and short pulse durations. These characteristics have limited the general utility of pulsed lasers because of the low duty cycle (low efficiency), pulse pile-up detection difficulties (limited dynamic range), and relatively poor stability (poor precision). In contrast, cw lasers offer 100% effective duty cycles, well-controlled laser profiles (spectrally, spatially and temporally), and excellent power stability. The main feature limiting the utility of cw lasers has been power. While sufficient intensity is available to saturate the resonant transition, efficient promotion of excited atoms to the ionization continuum is difficult. This last aspect is where the authors efforts have centered. Presently, they are pursuing an external cavity technique which will generate overall ionization efficiencies of tens of percent, as well as increase the available spectral range. Experimental aspects and process to date on thorium will be discussed in detail

  19. Mass Spectrometric Quantification of N-Linked Glycans by Reference to Exogenous Standards.

    Science.gov (United States)

    Mehta, Nickita; Porterfield, Mindy; Struwe, Weston B; Heiss, Christian; Azadi, Parastoo; Rudd, Pauline M; Tiemeyer, Michael; Aoki, Kazuhiro

    2016-09-01

    Environmental and metabolic processes shape the profile of glycoprotein glycans expressed by cells, whether in culture, developing tissues, or mature organisms. Quantitative characterization of glycomic changes associated with these conditions has been achieved historically by reductive coupling of oligosaccharides to various fluorophores following release from glycoprotein and subsequent HPLC or capillary electrophoretic separation. Such labeling-based approaches provide a robust means of quantifying glycan amount based on fluorescence yield. Mass spectrometry, on the other hand, has generally been limited to relative quantification in which the contribution of the signal intensity for an individual glycan is expressed as a percent of the signal intensity summed over the total profile. Relative quantification has been valuable for highlighting changes in glycan expression between samples; sensitivity is high, and structural information can be derived by fragmentation. We have investigated whether MS-based glycomics is amenable to absolute quantification by referencing signal intensities to well-characterized oligosaccharide standards. We report the qualification of a set of N-linked oligosaccharide standards by NMR, HPLC, and MS. We also demonstrate the dynamic range, sensitivity, and recovery from complex biological matrices for these standards in their permethylated form. Our results indicate that absolute quantification for MS-based glycomic analysis is reproducible and robust utilizing currently available glycan standards. PMID:27432553

  20. A Mass Spectrometric Analysis Method Based on PPCA and SVM for Early Detection of Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Jiang Wu

    2016-01-01

    Full Text Available Background. Surfaced-enhanced laser desorption-ionization-time of flight mass spectrometry (SELDI-TOF-MS technology plays an important role in the early diagnosis of ovarian cancer. However, the raw MS data is highly dimensional and redundant. Therefore, it is necessary to study rapid and accurate detection methods from the massive MS data. Methods. The clinical data set used in the experiments for early cancer detection consisted of 216 SELDI-TOF-MS samples. An MS analysis method based on probabilistic principal components analysis (PPCA and support vector machine (SVM was proposed and applied to the ovarian cancer early classification in the data set. Additionally, by the same data set, we also established a traditional PCA-SVM model. Finally we compared the two models in detection accuracy, specificity, and sensitivity. Results. Using independent training and testing experiments 10 times to evaluate the ovarian cancer detection models, the average prediction accuracy, sensitivity, and specificity of the PCA-SVM model were 83.34%, 82.70%, and 83.88%, respectively. In contrast, those of the PPCA-SVM model were 90.80%, 92.98%, and 88.97%, respectively. Conclusions. The PPCA-SVM model had better detection performance. And the model combined with the SELDI-TOF-MS technology had a prospect in early clinical detection and diagnosis of ovarian cancer.

  1. Mass spectrometric estimation of gas permeation coefficients for thin polymer membranes

    Science.gov (United States)

    Nörenberg, Holger; Miyamoto, T.; Tsukahara, Y.; Smith, G. D. W.; Briggs, G. A. D.

    1999-05-01

    We have developed a new method to estimate the permeation coefficient of gases through polymer membranes. A fixed volume of gas is put in a gas cell and introduced into ultrahigh vacuum. After positioning the gas cell to face a quadrupole mass spectrometer, the partial pressure of the gases are measured as function of time. In a simple model, the partial pressure as function of time obeys an exponential law. A formula is derived to calculate the permeation coefficient with the time constant of the partial pressure decay and geometric parameters of the gas cell as input. Using these parameters the method gives absolute permeation values without calibration. If the time constant is difficult to establish (this may happen for membranes with a low permeation coefficient), the permeation coefficient can be estimated by extrapolating the partial pressure to t=0. The method can be used to study the permeation behavior of individual components of gas mixtures. The sample size can be about two orders of magnitude smaller than usually used in conventional permeation measurements. The method is illustrated with oriented polypropylene and polyethylene terephtalate membranes of different thickness. The estimated permeation coefficients are in reasonable agreement with values obtained from a control experiment using a gas chromatograph and with values from the literature.

  2. Mass spectrometric analysis of spatio-temporal dynamics of crustacean neuropeptides.

    Science.gov (United States)

    OuYang, Chuanzi; Liang, Zhidan; Li, Lingjun

    2015-07-01

    Neuropeptides represent one of the largest classes of signaling molecules used by nervous systems to regulate a wide range of physiological processes. Over the past several years, mass spectrometry (MS)-based strategies have revolutionized the discovery of neuropeptides in numerous model organisms, especially in decapod crustaceans. Here, we focus our discussion on recent advances in the use of MS-based techniques to map neuropeptides in the spatial domain and monitoring their dynamic changes in the temporal domain. These MS-enabled investigations provide valuable information about the distribution, secretion and potential function of neuropeptides with high molecular specificity and sensitivity. In situ MS imaging and in vivo microdialysis are highlighted as key technologies for probing spatio-temporal dynamics of neuropeptides in the crustacean nervous system. This review summarizes the latest advancement in MS-based methodologies for neuropeptide analysis including typical workflow and sample preparation strategies as well as major neuropeptide families discovered in decapod crustaceans. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.

  3. Mass spectrometric dereplication of nitrogen-containing constituents of black cohosh (Cimicifuga racemosa L.)

    Science.gov (United States)

    Nikolić, Dejan; Gödecke, Tanja; Chen, Shao-Nong; White, Jerry; Lankin, David C.; Pauli, Guido F.; van Breemen, Richard B.

    2011-01-01

    Black cohosh preparations are popular dietary supplements among women seeking alternative treatments for menopausal complaints. For decades, triterpene glycosides and phenolic acids have dominated the phytochemical and biomedical research on this plant. In this study, we provide evidence that black cohosh contains an unexpected and highly diverse group of secondary nitrogenous metabolites previously unknown to exist in this plant. Using a dereplication approach that combines accurate mass measurements, database searches and general knowledge of biosynthetic pathways of natural products, we identified or tentatively identified 73 nitrogen-containing metabolites, many of which are new natural products. The identified compounds belong to several structural groups including alkaloids, amides or esters of hydroxycinnamic acids and betains. Among the alkaloids, several classes such as guanidino alkaloids, isoquinolines and β-carbolines were identified. Fragmentation patterns for major compound classes are discussed, which provides a framework for the discovery of these compounds from other sources. Identification of alkaloids as a well-known group of bioactive natural products represents an important advance in better understanding of the pharmacological profile of black cohosh. PMID:22178683

  4. Mass spectrometric investigation of molecular variability of grass pollen group 1 allergens.

    Science.gov (United States)

    Fenaille, François; Nony, Emmanuel; Chabre, Henri; Lautrette, Aurélie; Couret, Marie-Noëlle; Batard, Thierry; Moingeon, Philippe; Ezan, Eric

    2009-08-01

    Natural grass pollen allergens exhibit a wide variety of isoforms. Precise characterization of such microheterogeneity is essential to improve diagnosis and design appropriate immunotherapies. Moreover, standardization of allergen vaccine production is a prerequisite for product safety and efficiency. Both qualitative and quantitative analytical methods are thus required to monitor and control the huge natural variability of pollens, as well as final product quality. A proteomic approach has been set up to investigate in depth the structural variability of five group 1 allergens originating from distinct grass species (Ant o 1, Dac g 1, Lol p 1, Phl p 1, and Poa p 1). Whereas group 1 is the most conserved grass pollen allergen, great variations were shown between the various isoforms found in these five species using mass spectrometry, with many amino acid exchanges, as well as variations in proline hydroxylation level and in main N-glycan motifs. The presence of O-linked pentose residues was also demonstrated, with up to three consecutive units on the first hydroxyproline of Ant o 1. In addition, species-specific peptides were identified that might be used for product authentication or individual allergen quantification. Lastly, natural or process-induced modifications (deamidation, oxidation, glycation) were evidenced, which might constitute useful indicators of product degradation. PMID:19572759

  5. Comparison of extraction techniques and mass spectrometric ionization modes in the analysis of wine volatile carbonyls

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Julian; Mateo-Vivaracho, Laura; Cacho, Juan [Laboratory for Flavor Analysis and Enology, Institute of Engineering of Aragon, I3A, Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza (Spain); Ferreira, Vicente, E-mail: vferre@unizar.es [Laboratory for Flavor Analysis and Enology, Institute of Engineering of Aragon, I3A, Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza (Spain)

    2010-02-15

    This work presents a comparative study of the analytical characteristics of two methods for the analysis of carbonyl compounds in wine, both based on the derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA). In the first method derivatives are formed in the solid phase extraction (SPE) cartridge in which the analytes have been previously isolated, while in the second method derivatives are formed in a solid phase microextraction (SPME) fibre saturated with vapors of the reagent and exposed to the sample headspace. In both cases detection has been carried out by electron impact (EI) or negative chemical ionization (NCI) mass spectrometry. The possibility of determining haloanisols simultaneously has been also considered. The method based on SPE presents, in general, better analytical properties than the SPME one. Although linearity was satisfactory for both methods (R{sup 2} > 0.99), repeatability of the SPE method (RSD < 10%) was better than that obtained with SPME (9% < RSD < 20%). Detection limits obtained with EI are better for the SPE method except for trihaloanisols, while with NCI detection limits for both strategies are comparable, although the SPME strategy presents worse results for ketones and methional. Detection limits are always lower with NCI, being the improvement most notable for SPME. Recovery experiments show that in the case of SPE, uncertainties are lower than 12% in all cases, while with the SPME method the imprecision plus the existence of matrix effects make the global uncertainty to be higher than 15%.

  6. New triterpenic acids from Uncaria rhynchophylla: chemistry, NO-inhibitory activity, and tandem mass spectrometric analysis.

    Science.gov (United States)

    Zhang, Yi-bei; Yang, Wen-zhi; Yao, Chang-liang; Feng, Rui-hong; Yang, Min; Guo, De-an; Wu, Wan-ying

    2014-07-01

    Five new oleanane and ursane type triterpenes, namely uncarinic acids F-J (1-5), together with six known triterpenic acids (6-11) were isolated from the stems and hooks of Uncaria rhynchophylla. Structure elucidation of 1-5 was based on the integrated analyses of high-resolution MS data, 1D ((1)H NMR, (13)C NMR, DEPT) and 2D (HSQC, HMBC, ROESY) NMR spectra. Compounds 4, 10, and 11 exhibited weak inhibitory effects on LPS-induced NO production in RAW264.7 cells (with IC50 1.48, 7.01, and 1.89 μM, respectively) with dexamethasone (IC50 0.04 μM) and quercetin (IC50 0.86 μM) as the positive controls. 19-OH substituted oleanane triterpenic acids (1, 2, 5, 8) were prone to eliminate CH2O3, whereas those ursane-type encompassing 19-OH (3, 6, 7, 9, 4) were featured by preferred cleavage of H2O while performing the negative collision-induced MS/MS fragmentation on an LTQ/Orbitrap mass spectrometer. PMID:24727084

  7. The Use of Mass Spectrometric Techniques to Differentiate Isobaric and Isomeric Flavonoid Conjugates from Axyris amaranthoides

    Directory of Open Access Journals (Sweden)

    Łukasz Marczak

    2016-09-01

    Full Text Available Flavonoids are a group of compounds that are commonly found in various plants, where they play important roles in many processes, including free radical scavenging and UV protection. These compounds can also act as chemical messengers, physiological regulators or protectants against pathogens in the defense reactions of plants. Flavonoid activity is regulated by the addition of various substituents, usually mono- or oligosaccharides of common sugars, such as glucose, rhamnose or galactose. In some plants, glucuronic acid is attached, and this sugar is often acylated by phenylpropanoic acids. Identification of these compounds and their derivatives is of great importance to understanding their role in plant metabolism and defense mechanisms; this research is important because flavonoids are frequently a significant constituent of the human diet. In this study, we identify the flavonoid conjugates present in Axyris amaranthoides L. extracts and demonstrate the usefulness of high-resolution mass spectrometry (HRMS analyzers for the differentiation of isobaric compounds and the utility of fragmentation spectra for the differentiation of isomeric structures. According to our knowledge, some of the structures, especially dehydrodiferulated conjugates of tricin, whose structures are proposed here have been found for the first time in plant material.

  8. Diagnostic Accuracy of MALDI Mass Spectrometric Analysis of Unfractionated Serum in Lung Cancer

    Science.gov (United States)

    Yildiz, Pinar B.; Shyr, Yu; Rahman, Jamshedur S. M.; Wardwell, Noel R.; Zimmerman, Lisa J.; Shakhtour, Bashar; Gray, William H.; Chen, Shuo; Li, Ming; Roder, Heinrich; Liebler, Daniel C.; Bigbee, William L.; Siegfried, Jill M.; Weissfeld, Joel L.; Gonzalez, Adriana L.; Ninan, Mathew; Johnson, David H.; Carbone, David P.; Caprioli, Richard M.; Massion, Pierre P.

    2014-01-01

    Purpose There is a critical need for improvements in the noninvasive diagnosis of lung cancer. We hypothesized that matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) analysis of the most abundant peptides in the serum may distinguish lung cancer cases from matched controls. Patients and Methods We used MALDI MS to analyze unfractionated serum from a total of 288 cases and matched controls split into training (n = 182) and test sets (n = 106). We used a training–testing paradigm with application of the model profile defined in a training set to a blinded test cohort. Results Reproducibility and lack of analytical bias was confirmed in quality-control studies. A serum proteomic signature of seven features in the training set reached an overall accuracy of 78%, a sensitivity of 67.4%, and a specificity of 88.9%. In the blinded test set, this signature reached an overall accuracy of 72.6 %, a sensitivity of 58%, and a specificity of 85.7%. The serum signature was associated with the diagnosis of lung cancer independently of gender, smoking status, smoking pack-years, and C-reactive protein levels. From this signature, we identified three discriminatory features as members of a cluster of truncated forms of serum amyloid A. Conclusions We found a serum proteomic profile that discriminates lung cancer from matched controls. Proteomic analysis of unfractionated serum may have a role in the noninvasive diagnosis of lung cancer and will require methodological refinements and prospective validation to achieve clinical utility. PMID:17909350

  9. Vaporisation studies on tellurium dioxide: A Knudsen effusion mass spectrometric study.

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmi Narasimhan, T.S. [Indira Gandhi Centre for Atomic Res., Kalpakkam (India). Mater. Chem. Div.; Balasubramanian, R. [Indira Gandhi Centre for Atomic Res., Kalpakkam (India). Mater. Chem. Div.; Nalini, S. [Indira Gandhi Centre for Atomic Res., Kalpakkam (India). Mater. Chem. Div.; Sai Baba, M. [Indira Gandhi Centre for Atomic Res., Kalpakkam (India). Mater. Chem. Div.

    1997-08-01

    The vaporisation of TeO{sub 2}(s) was studied by Knudsen effusion mass spectrometry. The vapour phase was found to consist of (TeO{sub 2}){sub n} (n=1-3)(g), (TeO){sub n}(g) (n=1-3) and Te{sub 2}(g). The p-T relations of TeO{sub 2}(g), (TeO{sub 2}){sub 2}(g) and (TeO{sub 2}){sub 3}(g) were derived to be log(p/Pa)=(-13 534{+-}78)/T+(14.241{+-}0.09) (750-950 K), log(p/Pa)=(-14 823{+-}212)/T+(14.373{+-}0.242) (825-950 K) and log(p/Pa)=(-19 074{+-}540)/T+(17.337{+-}0.606) (850-921 K) respectively. From the partial pressures, {Delta}{sub r}H{sub 298.15}{sup 0} of nTeO{sub 2}(s)=(TeO{sub 2}){sub n}(g) (n=1-3) were evaluated by second and third law methods. Also, enthalpy of the pressure independent reaction TeO{sub 2}(s)+TeO{sub 2}(g)=(TeO{sub 2}){sub 2}(g) has been evaluated. Using the {Delta}{sub f}H{sub 298.15}{sup 0} of TeO{sub 2}(s), {Delta}{sub f}H{sub 298.15}{sup 0} of (TeO{sub 2}){sub n}(g) (n=1-3) were calculated. The partial pressure and enthalpy data for (TeO{sub 2}){sub 3}(g) have been obtained for the first time. (orig.).

  10. Vaporisation studies on tellurium dioxide: A Knudsen effusion mass spectrometric study

    International Nuclear Information System (INIS)

    The vaporisation of TeO2(s) was studied by Knudsen effusion mass spectrometry. The vapour phase was found to consist of (TeO2)n (n=1-3)(g), (TeO)n(g) (n=1-3) and Te2(g). The p-T relations of TeO2(g), (TeO2)2(g) and (TeO2)3(g) were derived to be log(p/Pa)=(-13 534±78)/T+(14.241±0.09) (750-950 K), log(p/Pa)=(-14 823±212)/T+(14.373±0.242) (825-950 K) and log(p/Pa)=(-19 074±540)/T+(17.337±0.606) (850-921 K) respectively. From the partial pressures, ΔrH298.150 of nTeO2(s)=(TeO2)n(g) (n=1-3) were evaluated by second and third law methods. Also, enthalpy of the pressure independent reaction TeO2(s)+TeO2(g)=(TeO2)2(g) has been evaluated. Using the ΔfH298.150 of TeO2(s), ΔfH298.150 of (TeO2)n(g) (n=1-3) were calculated. The partial pressure and enthalpy data for (TeO2)3(g) have been obtained for the first time. (orig.)

  11. Photochemical vapor generation of lead for inductively coupled plasma mass spectrometric detection

    Science.gov (United States)

    Duan, Hualing; Zhang, Ningning; Gong, Zhenbin; Li, Weifeng; Hang, Wei

    2016-06-01

    Photochemical vapor generation (PCVG) of lead was successfully achieved with a simplified and convenient system, in which only low molecular weight organic acid and a high-efficiency photochemical reactor were needed. The reactor was used to generate lead volatile species when a solution of lead containing a small amount of low molecular weight organic acid was pumped through. Several factors, including the concentration of acetic acid, the concentration of hydrochloride acid, and the irradiation time of UV light were optimized. Under the optimal conditions, including the addition of 0.90% (v/v) acetic acid and 0.03% (v/v) hydrochloride acid, and irradiation time of 28 s, intense and repeatable signal of lead volatile species was successfully obtained and identified with inductively coupled plasma mass spectrometry (ICPMS). In addition, the effects from inorganic anions and transition metal ions, including Cl-, NO3-, SO42 -, Cu2 +, Fe3 +, Co2 + and Ni2 +, were investigated, which suggests that their suppression to the PCVG of lead was in the order of Cl- < SO42 - < NO3- for anions and Ni2 +, Co2 + < Fe3 + < Cu2 + for transition metal ions. Under optimized conditions, relative standard derivation (RSD) of 4.4% was achieved from replicate measurements (n = 5) of a standard solution of 0.1 μg L- 1 lead. And, the limit of quantitation (LOQ, 10σ) of 0.012 μg L- 1 lead was obtained using this method and the method blank could be easily controlled down to 0.023 μg L- 1. To validate applicability of this method, it was also employed for the determination of lead in tap water, rain water and lake water.

  12. Characterization of Peptide Polymer Interactions in Poly(alkylcyanoacrylate) Nanoparticles: A Mass Spectrometric Approach.

    Science.gov (United States)

    Kafka, Alexandra P; Kleffmann, Torsten; Rades, Thomas; McDowell, Arlene

    2010-07-01

    Drug/polymer interactions occur during in situ polymerization of poly(alkylcyanoacrylate) (PACA) formulations. We have used MALDI ionization coupled tandem time-of-flight (TOF) mass spectrometry as an accurate method to characterize covalent peptide/polymer interactions of PACA nanoparticles with the bioactives D-Lys6-GnRH, insulin, [Asn1-Val5]-angiotensin II, and fragments of insulin-like growth factor 1 (IGF-1 (1-3)) and human adrenocorticotropic hormone (h-ACTH, (18-39)) at the molecular level. Covalent interactions of peptide with alkylcyanoacrylate were identified for D-Lys6-GnRH, [Asn1-Val5]-angiotensin II and IGF-1 (1-3). D-Lys6-GnRH and [Asn1-Val5]-angiotensin II were modified at their histidine side chain within the peptide, whilst IGF-1 (1-3) was modified at the C-terminal glutamic acid residue. The more complex protein insulin was not modified despite the presence of 2 histidine residues. This might be explained by the engagement of histidine residues in the folding and sterical arrangement of insulin under polymerization conditions. As expected, h-ACTH (18-39) that does not contain histidine residues did not interfere in the polymerization process. Lowering the pH did not prevent the covalent association of PACA with D-Lys6-GnRH or IGF-1 (1-3). Conclusively, protein and peptide bioactives are potentially reactive towards alkylcyanoacrylate monomers via various mechanisms with limited interference of pH. Histidines and C-terminal glutamic acid residues have been identified as potential sites of interaction. The likelihood of their engagement in the polymerization process (initiators), however, seems dependent on their sterical availability. The reactivity of nucleophilic functional groups should always be considered and bioactives examined for their potential to covalently interfere with alkylcyanoacrylate monomers, especially when designing PACA delivery systems for protein and peptide biopharmaceuticals.

  13. Mass Spectrometric Observation of Doubly Charged Alkaline-Earth Argon Ions.

    Science.gov (United States)

    Hattendorf, Bodo; Gusmini, Bianca; Dorta, Ladina; Houk, Robert S; Günther, Detlef

    2016-09-01

    Doubly charged diatomic ions MAr(2+) where M=Mg, Ca, Sr or Ba have been observed by mass spectrometry with an inductively coupled plasma ion source. Abundance ratios are quite high, 0.1 % for MgAr(2+) , 0.4 % for CaAr(2+) , 0.2 % for SrAr(2+) and 0.1 % for BaAr(2+) relative to the corresponding doubly charged atomic ions M(2+) . It is assumed that these molecular ions are formed through reactions of the doubly charged metal ions with neutral argon atoms within the ion source. Bond dissociation energies (D0 ) were calculated and agree well with previously published values. The abundance ratios MAr(+) /M(+) and MAr(2+) /M(2+) generally follow the predicted bond dissociation energies with the exception of MgAr(2+) . Mg(2+) should form the strongest bond with Ar [D0 (MgAr(2+) )=124 to 130 kJ mol(-1) ] but its relative abundance is similar to that of the weakest bound BaAr(2+) (D0 =34 to 42 kJ mol(-1) ). The relative abundances of the various MAr(2+) ions are higher than those expected from an argon plasma at T=6000 K, indicating that collisions during ion extraction reduce the abundance of the MAr(2+) ions relative to the composition in the source. The corresponding singly charged MAr(+) ions are also observed but occur at about three orders of magnitude lower intensity than MAr(2+) . PMID:27252087

  14. Linear ion-trap mass spectrometric characterization of human pituitary nitrotyrosine-containing proteins

    Science.gov (United States)

    Zhan, Xianquan; Desiderio, Dominic M.

    2007-01-01

    The nitric oxide-mediated Tyr-nitration of endogenous proteins is associated with several pathological and physiological processes. In order to investigate the presence - and potential roles - of Tyr-nitration in the human pituitary, a large-format two-dimensional gel separation plus a Western blot against a specific anti-3-nitrotyrosine antibody were used to separate and detect nitroproteins from a human pituitary proteome. The nitroproteins were subjected to in-gel trypsin digestion, and high-sensitivity vacuum matrix-assisted laser desorption/ionization (vMALDI) linear ion-trap tandem mass spectrometry was used to analyze the tryptic peptides. Those MS/MS data were used to determine the amino acid sequence and the specific nitration site of each tryptic nitropeptide, and were matched to corresponding proteins with Bioworks TuboSEQUEST software. Compared to our previous study, 16 new nitrotyrosine-immunoreactive positive Western blot spots were found within the area pI 3.0-10 and Mr 10-100 kDa. Four new nitroproteins were discovered: the stanniocalcin 1 precursor--involved in calcium and phosphate metabolism; mitochondrial co-chaperone protein HscB, which might act as a co-chaperone in iron-sulfur cluster assembly in mitochrondria; progestin and adipoQ receptor family member III--a seven-transmembrane receptor; proteasome subunit alpha type 2--involved in an ATP/ubiquitin-dependent non-lysosomal proteolytic pathway. Those data demonstrate that nitric oxide-mediated Tyr-nitration might participate in various biochemical, metabolic, and pathological processes in the human pituitary.

  15. iMS2Flux – a high–throughput processing tool for stable isotope labeled mass spectrometric data used for metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Poskar C Hart

    2012-11-01

    Full Text Available Abstract Background Metabolic flux analysis has become an established method in systems biology and functional genomics. The most common approach for determining intracellular metabolic fluxes is to utilize mass spectrometry in combination with stable isotope labeling experiments. However, before the mass spectrometric data can be used it has to be corrected for biases caused by naturally occurring stable isotopes, by the analytical technique(s employed, or by the biological sample itself. Finally the MS data and the labeling information it contains have to be assembled into a data format usable by flux analysis software (of which several dedicated packages exist. Currently the processing of mass spectrometric data is time-consuming and error-prone requiring peak by peak cut-and-paste analysis and manual curation. In order to facilitate high-throughput metabolic flux analysis, the automation of multiple steps in the analytical workflow is necessary. Results Here we describe iMS2Flux, software developed to automate, standardize and connect the data flow between mass spectrometric measurements and flux analysis programs. This tool streamlines the transfer of data from extraction via correction tools to 13C-Flux software by processing MS data from stable isotope labeling experiments. It allows the correction of large and heterogeneous MS datasets for the presence of naturally occurring stable isotopes, initial biomass and several mass spectrometry effects. Before and after data correction, several checks can be performed to ensure accurate data. The corrected data may be returned in a variety of formats including those used by metabolic flux analysis software such as 13CFLUX, OpenFLUX and 13CFLUX2. Conclusion iMS2Flux is a versatile, easy to use tool for the automated processing of mass spectrometric data containing isotope labeling information. It represents the core framework for a standardized workflow and data processing. Due to its flexibility

  16. Calcinated gold nanoparticle arrays for on-chip, multiplexed and matrix-free mass spectrometric analysis of peptides and small molecules

    Science.gov (United States)

    Hinman, Samuel S.; Chen, Chih-Yuan; Duan, Jicheng; Cheng, Quan

    2016-01-01

    A patterned gold nanoparticle microarray, functionalized with a nanoscale silicate coating, has been developed for on-chip, high-throughput mass spectrometric analyses of biomolecules with minimal sample preparation and reagent costs. Fabrication was realized by the combination of layer-by-layer functionalization of the nanoparticles with suitable polyelectrolytes, followed by fluidic patterning of the glass microarray support and calcination for permanent fixation of the nano-coating. Performance of the microarray was evaluated for surface-assisted laser-desorption/ionization mass spectrometry (SALDI-MS), where the nano-silicate coating was found to enhance SALDI efficiency, resulting in comparable performance to some common organic matrices for small and medium sized molecules. Performance contributing factors of this material have been discussed; heat confinement and interband transition/plasmonic resonance may play important roles. Taking the accessibility of fabrication, performance, and reusability of this substrate together, the material developed here provides a new tool for multiplexed and chip-based mass spectrometric analysis.A patterned gold nanoparticle microarray, functionalized with a nanoscale silicate coating, has been developed for on-chip, high-throughput mass spectrometric analyses of biomolecules with minimal sample preparation and reagent costs. Fabrication was realized by the combination of layer-by-layer functionalization of the nanoparticles with suitable polyelectrolytes, followed by fluidic patterning of the glass microarray support and calcination for permanent fixation of the nano-coating. Performance of the microarray was evaluated for surface-assisted laser-desorption/ionization mass spectrometry (SALDI-MS), where the nano-silicate coating was found to enhance SALDI efficiency, resulting in comparable performance to some common organic matrices for small and medium sized molecules. Performance contributing factors of this material

  17. Mass spectrometric analysis of the marine lipophilic biotoxins pectenotoxin-2 and okadaic acid by four different types of mass spectrometers

    NARCIS (Netherlands)

    Gerssen, A.; Mulder, P.P.J.; Rhijn, van J.A.; Boer, de J.

    2008-01-01

    The performances of four different mass spectrometers [triple-quadrupole (TQ), time-of-flight (ToF), quadrupole ToF (Q-ToF) and ion trap (IT)] for the detection of the marine lipophilic toxins pectenotoxin-2 (PTX2) and okadaic acid (OA) were investigated. The spectral data obtained with the differen

  18. NMR and mass spectrometric characterization of vinblastine, vincristine and some new related impurities - part I.

    Science.gov (United States)

    Dubrovay, Zsófia; Háda, Viktor; Béni, Zoltán; Szántay, Csaba

    2013-10-01

    In the course of exploring the possibilities of developing a new, improved process at Gedeon Richter for the production of the "bisindole" alkaloids vinblastine (VLB) and vincristine (VCR), some novel VLB/VCR-related trace impurities were detected by analytical HPLC. Following isolation by preparative HPLC, a combination of 1D and 2D ultra high-field NMR and high-resolution (HR) (LC-)MS/MS studies allowed the structural identification and complete spectral characterization of several hitherto unpublished VLB/VCR-analogue impurities. Since the impurities could not be isolated in entirely pure forms and were available only in minute, mass-limited quantities, accessing the spectral information needed for their ab initio structure determination was met with various practical difficulties. Successful structure determination therefore relied heavily on the availability and use of detailed and definitive spectral data for both VLB and VCR. In particular, the utilization of detailed (1)H, (13)C, and (15)N NMR assignments as well as (1)H-(1)H, (1)H-(13)C and (1)H-(15)N spin-spin connectivities pertaining to different solvents for VLB/VCR base and sulphate salt was required. Although NMR studies on VLB base and other bisindoles were reported earlier in the literature, an NMR characterization of VLB and VCR under the above-mentioned circumstances and using ultra-high field instrumentation is either scarcely available or entirely lacking, therefore the necessary data had to be obtained in-house. Likewise, a modern tandem HR-ESI-MS/MS(n) fragmentation study of VLB and VCR has not been published yet. In the present paper we therefore give a thorough NMR and MS characterization of VLB and VCR specifically with a view to filling this void and to provide sufficiently extensive and solid reference data for the structural investigation of the aforementioned VLB/VCR impurities. Besides being scientifically relevant in its own right, the disclosed data should be useful for anyone

  19. Mass spectrometric QUAL/QUAN approaches for drug metabolism and metabolomics.

    Science.gov (United States)

    Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard

    2012-01-01

    A liquid chromatography-high-resolution mass spectrometry platform was used for simultaneous qualitative and quantitative (QUAL/QUAN) acquisition, enabling drug metabolism and metabolomics investi- gations. Plasma study samples were monitored for three different groups of patients at a single time-point (1 h after drug administration): one group received acetaminophen (APAP), one group received both APAP and ketorolac and one group was a control group. The quantification of APAP and two of its metabolites (APAP-glucuronide and APAP-cysteine) was performed on a fast acquisition quadrupole-Time-Of-Flight (50-100 ms duty cycle, resolving power of 30,000) compatible with UHPLC time constraints. High-resolution Selected Reaction Monitoring was used for quantification of APAP and its metabolites from 50-10,000 ng/mL using a 50 μL plasma aliquot. Average measured concentrations were for APAP 6,650 ng/mL vs 6,160 ng/mL, APAP-CYS concentrations were 154.2 ng/mL vs 140.6 ng/mL and APAP-GLU concentrations 8,750 ng/mL vs 8,430 ng/mL between the group that received only APAP (n = 11) and the group that received APAP in combination with ketorolac (n = 11). No major differences were observed between the two groups of patients, as it would be expected due to the differing metabolism pathway for both substances. For the qualitative aspect, a metabolomics data processing platform with biological QC samples was applied to the study samples to search for unanticipated metabolites and biomarkers related to APAP and ketorolac metabolism. Multivariate analysis (i.e. Principle Component Analysis), variables grouping tools (i.e. PCVG) and high-resolution MS(/MS) spectra from the MS(ALL) acquisition strategy enabled the profiling and characterization of circulating metabolites of APAP in plasma such as APAP-sulfate, APAP-mercapturate as well as ketorolac. PMID:22613154

  20. Thermodynamic modelling of Li–Sn liquid alloy based on Knudsen effusion mass spectrometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bencze, L., E-mail: bencze@chem.elte.hu [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Eötvös Loránd University, Dept. of Physical Chemistry, H-1117 Budapest, Pázmány Péter sétány 1/A (Hungary); Henriques, D. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Motalov, V. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Department of Physics, Ivanovo State University of Chemistry and Technology, Sheremetevsky av.7, 153000 Ivanovo (Russian Federation); Markus, T. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany)

    2014-09-01

    Highlights: • The experimental KEMS data fit well with the Redlich–Kister sub-regular solution model applied to Li–Sn melt. • The Redlich–Kister binary interaction L-parameters of the Li–Sn melt were provided in this work. • The experimental KEMS data fit well with the ideally associated mixture model, too. • The quantitative associate composition of the Li–Sn melt was given. • The thermodynamic properties of the associate-forming reactions were also provided. - Abstract: The mixing thermodynamic properties of liquid Li–Sn system, determined previously by Knudsen effusion mass spectrometry (KEMS), were successfully fitted to both Redlich–Kister (RK) sub-regular mixture and ideally associated mixture (IAMT) models. The RK binary interaction L parameters, as a function of temperature in the CALPHAD-type functional form, were obtained as follows: L{sup (0)}=-(108580±0.00171)+(16.4±1.6·10{sup -5})·T+(1.96496·10{sup -9}±2.03133·10{sup -6}) ·T·ln(T) L{sup (1)}=-(96600±4700)+(3.3±43.0)·T+(4.4±5.6)·T·ln(T) L{sup (2)}=-(64670±190)-(44.4±1.7)·T+(8.44±0.22)·T·ln(T) L{sup (3)}=-(20900±1500)-(29±14)·T+(4.3±1.8)·T·ln(T) The former literature data provided only qualitative information on possible liquid associates but no quantitative associate composition was given as a function of the sample composition and temperature. The experimental KEMS data in the composition range X{sub Li} = 0 to ∼0.7 fit well with the Li(l) + Sn(l) + LiSn(l) + LiSn{sub 2}(l) + Li{sub 2}Sn(l) associate model. At X{sub Li} > 0.7 no associate variations – including further associate variants such as Li{sub 4}Sn(l) etc. – could be fitted to the KEMS data. Nevertheless, in this work the Li(l) + Sn(l) + LiSn(l) + LiSn{sub 2}(l) + Li{sub 2}Sn(l) + Li{sub 4}Sn(l) + Li{sub 9}Sn(l) associate model was successfully fitted to the thermodynamic data of a selected literature study over the complete composition range. The thermodynamic data of the associate

  1. Advances in mass spectrometric characterization of naphthenic acids fraction compounds in oil sands environmental samples and crude oil--A review.

    Science.gov (United States)

    Headley, John V; Peru, Kerry M; Barrow, Mark P

    2016-01-01

    There has been a recent surge in the development of mass spectrometric methods for detailed characterization of naphthenic acid fraction compounds (all C(c)H(h)N(n)O(o)S(s), species, including heteroatomic and aromatic components in the acid-extractable fraction) in environmental samples. This surge is driven by the increased activity in oil sands environmental monitoring programs in Canada, the exponential increase in research studies on the isolation and toxicity identification of components in oil sands process water (OSPW), and the analytical requirements for development of technologies for treatment of OSPW. There has been additional impetus due to the parallel studies to control corrosion from naphthenic acids during the mining and refining of heavy bitumen and crude oils. As a result, a range of new mass spectrometry tools have been introduced since our last major review of this topic in 2009. Of particular significance are the developments of combined mass spectrometric methods that incorporate technologies such as gas chromatography, liquid chromatography, and ion mobility. There has been additional progress with respect to improved visualization methods for petroleomics and oil sands environmental forensics. For comprehensive coverage and more reliable characterization of samples, an approach based on multiple-methods that employ two or more ionization modes is recommended. On-line or off-line fractionation of isolated extracts, with or without derivatization, might also be used prior to mass spectrometric analyses. Individual ionization methods have their associated strengths and weaknesses, including biases, and thus dependence upon a single ionization method is potentially misleading. There is also a growing trend to not rely solely on low-resolution mass spectrometric methods (power at m/z 200) for characterization of complex samples. Future research is anticipated to focus upon (i) structural elucidation of components to determine the correlation

  2. Mass spectrometric analysis of small negative ions (e/m < 100) produced by Trichel pulse negative corona discharge fed by ozonised air

    OpenAIRE

    Skalny, J. D.; Horvath, G.; Mason, N

    2007-01-01

    Mass spectrometric analysis of small negative ions (e/m < 100) produced by DC negative corona discharge in ozonised wet air both in flow and flow-stopped regimes was conducted at pressure of 30 kPa. The point-to-plain electrode system has been used. The yield of individual ions is strongly affected by trace concentrations of ozone in both regimes. Ozone concentration greater than 25 ppm is sufficient to completely suppress the appearance of O2- and a NO2- ion as well as theirs clusters in the...

  3. MALDI-mass spectrometric imaging revealing hypoxia-driven lipids and proteins in a breast tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiang; Chughtai, Kamila; Purvine, Samuel O.; Bhujwalla, Zaver M.; Raman, Venu; Pasa-Tolic, Ljiljana; Heeren, Ronald M.; Glunde, Kristine

    2015-06-16

    Hypoxic areas are a common feature of rapidly growing malignant tumors and their metastases, and are typically spatially heterogeneous. Hypoxia has a strong impact on tumor cell biology and contributes to tumor progression in multiple ways. To date, only a few molecular key players in tumor hypoxia, such as for example hypoxia-inducible factor-1 (HIF-1), have been discovered. The distribution of biomolecules is frequently heterogeneous in the tumor volume, and may be driven by hypoxia and HIF-1α. Understanding the spatially heterogeneous hypoxic response of tumors is critical. Mass spectrometric imaging (MSI) provides a unique way of imaging biomolecular distributions in tissue sections with high spectral and spatial resolution. In this paper, breast tumor xenografts grown from MDA-MB-231-HRE-tdTomato cells, with a red fluorescent tdTomato protein construct under the control of a hypoxia response element (HRE)-containing promoter driven by HIF-1α, were used to detect the spatial distribution of hypoxic regions. We elucidated the 3D spatial relationship between hypoxic regions and the localization of small molecules, metabolites, lipids, and proteins by using principal component analysis – linear discriminant analysis (PCA-LDA) on 3D rendered MSI volume data from MDA-MB-231-HRE-tdTomato breast tumor xenografts. In this study we identified hypoxia-regulated proteins active in several distinct pathways such as glucose metabolism, regulation of actin cytoskeleton, protein folding, translation/ribosome, splicesome, the PI3K-Akt signaling pathway, hemoglobin chaperone, protein processing in endoplasmic reticulum, detoxification of reactive oxygen species, aurora B signaling/apoptotic execution phase, the RAS signaling pathway, the FAS signaling pathway/caspase cascade in apoptosis and telomere stress induced senescence. In parallel we also identified co-localization of hypoxic regions and various lipid species such as PC(16:0/18:1), PC(16:0/18:2), PC(18:0/18:1), PC

  4. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides ((U, Pu)O2)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides, (U, Pu)O2, powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Uranium in the Presence of Pu by Potentiometric Titration Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron (II) Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 7 to 14 Carbon (Total) by Direct Combustion-Thermal Conductivity 15 to 26 Total Chlorine and Fluorine by Pyrohydrolysis 27 to 34 Sulfur by Distillation-Spectrophotometry 35 to 43 Moisture by the Coulometric, Electrolytic Moisture Analyzer 44 to 51 Isotopic Composition by Mass Spectrometry Rare Earths by Copper Spark Spectroscopy 52 to 59 Trace Impurities by Carrier Distillation Spectroscopy 60 to 69 Impurities by Spark-Source Mass Spectrography 70 to 76 Total Gas in Reactor-Grade Mixed Dioxide P...

  5. Mass Spectrometric Fragmentation of 1,8-Bis[4-substituted-(oxazolin-2-yl)] anthracenes: Ring-contraction Rearrangement of Oxazoline Ring under Electron-Impact Ionization Conditions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mass spectrometric fragmentation of 1,8-bis[4-substituted(oxazolin-2-yl)] anthracenes(AnBOXes) was investigated by using mass-analyzed ion kinetic energy spectrometry under electron-impact ionization conditions. All the compounds could undergo a ring contraction by the loss of an RCH=CH2 molecule to form 1-oxazirinyl-8-(oxazolin-2-yl) anthracene ions, which could further lose an R radical, followed by the loss of oxazoline. These ions could also eliminate an R radical and subsequently undergo ring-contraction rearrangements to lose a CHCH2O fragment and an epoxide molecule, respectively. The ions that are formed could further lose CHCH2O and CH2=CH fragments. Several ring-contraction rearrangements of the oxazoline ring were observed under electron-impact ionization conditions.

  6. Identification of NTBC metabolites in urine from patients with hereditary tyrosinemia type 1 using two different mass spectrometric platforms: triple stage quadrupole and LTQ-Orbitrap.

    Science.gov (United States)

    Herebian, Diran; Lamshöft, Marc; Mayatepek, Ertan; Spiekerkoetter, Ute

    2010-03-01

    The objective of our work was to identify known and unknown metabolites of the drug NTBC (2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione) in urine from patients during the treatment of hereditary tyrosinemia type 1 (HT-1) disease, a severe inborn error of tyrosine metabolism. Two different mass spectrometric techniques, a triple stage quadrupole and an LTQ-Orbitrap (Fourier transform mass spectrometry (FTMS)), were used for the identification and the structural elucidation of the detected metabolites. Initially, the mass spectrometric (MS) approach consisted of the precursor ion scan detection of the selected product ions, followed by the corresponding collision-induced dissociation (CID) fragmentation analysis (MS(2)) for the targeted selected reaction monitoring (SRM) mode. Subsequently, accurate and high-resolution full scan and MS/MS measurements were performed on the possible metabolites using the LTQ-Orbitrap. Final confirmation of the identified metabolites was achieved by measuring commercially supplied or laboratory-synthesized standards. Altogether six metabolites, including NTBC itself, were extracted, detected and identified. In addition, two new NTBC metabolites were unambiguously identified as amino acid conjugates, namely glycine-NTBC and beta-alanine-NTBC. These identifications were based on their characteristics of chromatographic retention times, protonated molecular ions, elemental compositions, product ions (using CID and higher-energy C-trap dissociation (HCD) techniques) and synthesized references. The applied MS strategy, based on two different MS platforms (LC/MS/MS and FTMS), allowed the rapid identification analysis of the drug metabolites from human extracts and could be used for pharmaceutical research and drug development. PMID:20187082

  7. Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometric Analysis of the Recombinant Human Macrophage Colony Stimulating Factor Beta and Derivatives

    International Nuclear Information System (INIS)

    The potential of electrospray ionization (ESI) Fourier transform ion cyclotron mass spectrometry (FTICR-MS) to assist in the structural characterization of monomeric and dimeric derivatives of the macrophage colony stimulating factor B (rhM-CSF B) was assessed. Mass spectrometric analysis of the 49 kDa protein required the use of sustained off-resonance irradiation (SORI) in-trap cleanup to reduce adduction. High resolution mass spectra were acquired for a fully reduced and a fully S-cyanylated monomeric derivative (∼25 kDa). Mass accuracy for monomeric derivatives was better than 5 ppm, after applying a new calibration method (i.e., DeCAL) which eliminates space charge effects upon high accuracy mass measurements. This high mass accuracy allowed the direct determination of the exact number of incorporated cyanyl groups. Collisionally induced dissociation using SORI yielded b- and y-fragment ions within the N- and C-terminal regions for the monomeric derivatives, but obtaining information on other regions required proteolytic digestion, or potentially the use of alternative dissociation methods

  8. Development of high-spatial and high-mass resolution mass spectrometric imaging (MSI) and its application to the study of small metabolites and endogenous molecules of plants

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Ji Hyun [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    High-spatial and high-mass resolution laser desorption ionization (LDI) mass spectrometric (MS) imaging technology was developed for the attainment of MS images of higher quality containing more information on the relevant cellular and molecular biology in unprecedented depth. The distribution of plant metabolites is asymmetric throughout the cells and tissues, and therefore the increase in the spatial resolution was pursued to reveal the localization of plant metabolites at the cellular level by MS imaging. For achieving high-spatial resolution, the laser beam size was reduced by utilizing an optical fiber with small core diameter (25 μm) in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer. Matrix application was greatly improved using oscillating capillary nebulizer. As a result, single cell level spatial resolution of ~ 12 μm was achieved. MS imaging at this high spatial resolution was directly applied to a whole Arabidopsis flower and the substructures of an anther and single pollen grains at the stigma and anther were successfully visualized. MS imaging of high spatial resolution was also demonstrated to the secondary roots of Arabidopsis thaliana and a high degree of localization of detected metabolites was successfully unveiled. This was the first MS imaging on the root for molecular species. MS imaging with high mass resolution was also achieved by utilizing the LTQ-Orbitrap mass spectrometer for the direct identification of the surface metabolites on the Arabidopsis stem and root and differentiation of isobaric ions having the same nominal mass with no need of tandem mass spectrometry (MS/MS). MS imaging at high-spatial and high-mass resolution was also applied to cer1 mutant of the model system Arabidopsis thaliana to demonstrate its usefulness in biological studies and reveal associated metabolite changes in terms of spatial distribution and/or abundances compared to those of wild-type. The spatial

  9. Development of high-spatial and high-mass resolution mass spectrometric imaging (MSI) and its application to the study of small metabolites and endogenous molecules of plants

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Ji Hyun [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    High-spatial and high-mass resolution laser desorption ionization (LDI) mass spectrometric (MS) imaging technology was developed for the attainment of MS images of higher quality containing more information on the relevant cellular and molecular biology in unprecedented depth. The distribution of plant metabolites is asymmetric throughout the cells and tissues, and therefore the increase in the spatial resolution was pursued to reveal the localization of plant metabolites at the cellular level by MS imaging. For achieving high-spatial resolution, the laser beam size was reduced by utilizing an optical fiber with small core diameter (25 μm) in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer. Matrix application was greatly improved using oscillating capillary nebulizer. As a result, single cell level spatial resolution of ~ 12 μm was achieved. MS imaging at this high spatial resolution was directly applied to a whole Arabidopsis flower and the substructures of an anther and single pollen grains at the stigma and anther were successfully visualized. MS imaging of high spatial resolution was also demonstrated to the secondary roots of Arabidopsis thaliana and a high degree of localization of detected metabolites was successfully unveiled. This was the first MS imaging on the root for molecular species. MS imaging with high mass resolution was also achieved by utilizing the LTQ-Orbitrap mass spectrometer for the direct identification of the surface metabolites on the Arabidopsis stem and root and differentiation of isobaric ions having the same nominal mass with no need of tandem mass spectrometry (MS/MS). MS imaging at high-spatial and high-mass resolution was also applied to cer1 mutant of the model system Arabidopsis thaliana to demonstrate its usefulness in biological studies and reveal associated metabolite changes in terms of spatial distribution and/or abundances compared to those of wild-type. The spatial

  10. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A., E-mail: joseph.caruso@uc.edu; Landero-Figueroa, Julio

    2014-10-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag{sup +}) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg{sup −1} detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

  11. Gas chromatographic-mass spectrometric characterization of all acyclic C5-C7 alkenes from fluid catalytic cracked gasoline using polydimethylsiloxane and squalane stationary phases.

    Science.gov (United States)

    Soják, Ladislav; Addová, Gabriela; Kubinec, Róbert; Kraus, Angelika; Hu, Gengyuan

    2002-02-15

    Published retention indices of acyclic alkenes C5-C7 on squalane and polydimethylsiloxane as stationary phases were investigated, and reliable retention indices of alkenes from various sources were converted to separation systems used in a laboratory. Retention indices measured on available authentic commercial alkenes and on alkenic fraction of gasoline, published retention indices as well as means of GC-MS were used for verification of calculated retention indices. Retention of some gas chromatographic unseparated isomer pairs was obtained by mass spectrometric deconvolution using a specific single-ion monitoring. On the basis of these retention data, C5-C7 alkenes were identified and analyzed in the gasoline from fluid catalytic cracking. In the gasoline all 59 acyclic C5-C7 isomeric alkenes were determined at significantly different concentration levels.

  12. Determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using radiochemical separation combined with radiometric and mass spectrometric measurements

    DEFF Research Database (Denmark)

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin;

    2014-01-01

    This paper reports an analytical method for the determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using anion exchange chromatography in combination with extraction chromatography for chemical separation of Pu. Both radiometric methods (liquid scintillation......, this is critical for the measurement of plutonium isotopes using mass spectrometric technique. Although the chemical yield of Pu in the entire procedure is about 55%, the analytical results of IAEA soil 6 and IAEA-367 in this work are in a good agreement with the values reported in the literature or reference...... values, revealing that the developed method for plutonium determination in environmental samples is reliable. The measurement results of 239+240Pu by alpha spectrometry agreed very well with the sum of 239Pu and 240Pu measured by ICP-MS. ICP-MS can not only measure 239Pu and 240Pu separately but also 241...

  13. Thermospray ionization mass spectrometric characterization on thermal stability of developing pharmaceutical products; TSP shitsuryo bunsekiho ni yoru kaihatsu iyakuhin no netsuanteisei hyoka no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, T.; Ishizuka, Y. [Pharmacia and Upjohn Tsukuba Research Lab., Tsukuba (Japan)

    1998-08-01

    In order to ensure quality of pharmaceutical products, the data concerning stability of pharmaceutical products are a kind of important parameters. It is well known that hydrolytic ion peaks caused by heat at initial stage appear in the positions that do not correspond to the molecular ion peaks according to the thermospray ionization LC/MS. It is an obstacle for obtaining high quality LC/MS data, and it is necessary to minimize it by restraining the spray temperature. In this study, using thermospray ionization mass spectrometric analyzer, re-evaluation of an on-line investigation method of pharmaceutical products in solution is studied. And, an example of its application, namely, an application on two kinds of pharmaceutical products, PNU-52047 that is a kind of anticancer drugs (USAN name: Menogaril) and PNU-100766 that is antibiotic material used for mesitylene resistance yellow staphylococcus (MRSA) that is a reason of in hospital inflection, is illustrated. 6 refs., 7 figs.

  14. 质谱技术在DNA甲基化研究中的应用%Application of Mass Spectrometric Technology in DNA Methylation Study

    Institute of Scientific and Technical Information of China (English)

    黄新凤; 叶金波; 刘建军

    2015-01-01

    DNA methylation is one of most important epigenetic modifications, which mainly occurs in carbon-5 position of CpG nucleotide sequence in mammal genomes and relates to organism development, transposable silence, X chromosome inactivation and many diseases. The understanding for molecular mechanism of DNA methylation formation, maintenance and reconstruction remain limited. however, in order to find an optimal method for DNA methylation qualitative and quantitative analysis, mass spectrometric technology with high sensitivity, good performance, high precision, high resolution and good repeatability, has a great value in the study of DNA methylation. In the following, we will make a introduction of mass spectrometric technology application in whole genomic DNA methylation and promoter DNA methylation study.%DNA甲基化是最重要的表观遗传修饰之一,主要发生在哺乳动物基因组CpG核苷酸序列中的胞嘧啶C-5位点,并与机体生长发育、转座子沉默、X染色体失活及许多疾病的发生相关。但对DNA甲基化的形成、维持和重构的分子机制的认识是有限的,需要从基因组水平寻找最优的DNA甲基化定性和定量分析方法,而质谱技术以高敏感性、高通量、高准确率、高分辨率、快速且重复性好等优势在该研究领域具有较大的应用价值。介绍质谱技术在全基因组DNA甲基化和启动子区甲基化分析中的应用。

  15. Inventory of metal complexes circulating in plant fluids: a reliable method based on HPLC coupled with dual elemental and high-resolution molecular mass spectrometric detection.

    Science.gov (United States)

    Flis, Paulina; Ouerdane, Laurent; Grillet, Louis; Curie, Catherine; Mari, Stéphane; Lobinski, Ryszard

    2016-08-01

    Description of metal species in plant fluids such as xylem, phloem or related saps remains a complex challenge usually addressed either by liquid chromatography-mass spectrometry, X-ray analysis or computational prediction. To date, none of these techniques has achieved a complete and true picture of metal-containing species in plant fluids, especially for the least concentrated complexes. Here, we present a generic analytical methodology for a large-scale (> 10 metals, > 50 metal complexes) detection, identification and semiquantitative determination of metal complexes in the xylem and embryo sac liquid of the green pea, Pisum sativum. The procedure is based on direct injection using hydrophilic interaction chromatography with dual detection by elemental (inductively coupled plasma mass spectrometry) and molecular (high-resolution electrospray mass spectrometry) mass spectrometric detection. Numerous and novel complexes of iron(II), iron(III), copper(II), zinc, manganese, cobalt(II), cobalt(III), magnesium, calcium, nickel and molybdenum(IV) with several ligands including nicotianamine, citrate, malate, histidine, glutamine, aspartic acid, asparagine, phenylalanine and others are observed in pea fluids and discussed. This methodology provides a large inventory of various types of metal complexes, which is a significant asset for future biochemical and genetic studies into metal transport/homeostasis. PMID:27111838

  16. Parallel development of chromatographic and mass-spectrometric methods for quantitative analysis of glycation on an IgG1 monoclonal antibody.

    Science.gov (United States)

    Viski, Kornél; Gengeliczki, Zsolt; Lenkey, Krisztián; Baranyáné Ganzler, Katalin

    2016-10-01

    Monitoring post-translational modifications (PTMs) in biotherapeutics is of paramount importance. In pharmaceutical industry, chromatography with optical detection is the standard choice of quantitation of product related impurities; and mass spectrometry is used only for characterization. Parallel development of a boronate affinity chromatographic (BAC) and a mass spectrometric methods for quantitative measurement of glycation on a monoclonal antibody (mAb) shed light on the importance of certain characteristics of the individual methods. Non-specific interactions in BAC has to be suppressed with the so-called shielding reagent. We have found that excessive amount of shielding reagents in the chromatographic solvents may cause significant underestimation of glycation. Although contamination of the retained peak with the non-glycated isoforms in BAC is unavoidable, our work shows that it can be characterized and quantitated by mass spectrometry. It has been demonstrated that glycation can be measured by mass spectrometry at the intact protein level with an LOQ value of 3.0% and error bar of ±0.5%. The BAC and MS methods have been found to provide equivalent results. These methods have not been compared from these points of view before.

  17. Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid - a mass spectrometric study of SOA aging

    Science.gov (United States)

    Müller, L.; Reinnig, M.-C.; Naumann, K. H.; Saathoff, H.; Mentel, T. F.; Donahue, N. M.; Hoffmann, T.

    2012-02-01

    This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pinene SOA product and a tracer compound for terpene SOA, is formed from the oxidation of pinonic acid and that this oxidation takes place in the gas phase. This finding is confirmed by temperature-dependent aging experiments on whole SOA formed from α-pinene, in which the yield of MBTCA scales with the pinonic acid fraction in the gas phase. Based on the results, several feasible gas-phase radical mechanisms are discussed to explain the formation of MBTCA from OH-initiated pinonic acid oxidation.

  18. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Boron by Titrimetry 7 to 13 Separation of Boron for Mass Spectrometry 14 to 19 Isotopic Composition by Mass Spectrometry 20 to 23 Separation of Halides by Pyrohydrolysis 24 to 27 Fluoride by Ion-Selective Electrode 28 to 30 Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 31 to 33 Trace Elements by Emission Spectroscopy 34 to 46 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (F...

  19. Pilot study of gas chromatographic-mass spectrometric screening of newborn urine for inborn errors of metabolism after treatment with urease.

    Science.gov (United States)

    Kuhara, T; Shinka, T; Inoue, Y; Ohse, M; Zhen-wei, X; Yoshida, I; Inokuchi, T; Yamaguchi, S; Takayanagi, M; Matsumoto, I

    1999-08-01

    Gas chromatographic-mass spectrometric (GC-MS) techniques for urinary organic acid profiling have been applied to high-risk screening for a wide range of diseases, mainly for inborn errors of metabolism (IEM), rather than to low-risk screening or mass screening. Using a simplified procedure with urease-pretreatment and the GC-MS technique, which allows simultaneous determination of organic acids, amino acids, sugars and sugar acids, we performed a pilot study of the application of this procedure to neonatal urine screening for 22 IEM. Out of 16,246 newborns screened, 11 cases of metabolic disorders were chemically diagnosed: two each of methylmalonic aciduria and glyceroluria, four of cystinuria, and one each of Hartnup disease, citrullinemia and alpha-aminoadipic aciduria/alpha-ketoadipic aciduria. The incidence of IEM was thus one per 1477, which was higher than the one per 3000 obtained in the USA in a study targeting amino acids and acylcarnitines in newborn blood spots by tandem mass spectrometry. Also, 227 cases were found to have transient metabolic abnormalities: 108 cases with neonatal tyrosinuria, 99 cases with neonatal galactosuria, and 20 cases with other transient metabolic disorders. Two hundred and thirty-eight cases out of 16,246 neonates (approximately 1/68) were thus diagnosed using this procedure as having either persistent or transient metabolic abnormalities. PMID:10492000

  20. Identification strategy using combined mass spectrometric techniques for elucidation of phase I and phase II in vitro metabolites of lipophilic marine biotoxins.

    Science.gov (United States)

    Kittler, Katrin; Preiss-Weigert, Angelika; These, Anja

    2010-11-15

    Combining mass spectrometric tools, a total of 47 in vitro metabolites of okadaic acid (OA), dinophysistoxins 1 and 2 (DTX1 and DTX2), yessotoxin (YTX), azaspiracid1 (AZA1), and pectenotoxin 2 (PTX2) could be detected and confirmed after an incubation with rat liver S9-mix. In a first step, liquid chromatography (LC) combined with tandem mass spectrometry (MS/MS) was used as a screening tool for the identification of in vitro metabolites of lipophilic marine biotoxins. Metabolic phase I and phase II reactions were screened for metabolites by calculating and subsequently monitoring theoretical MS transitions. In a second step, metabolites were confirmed by determination of accurate masses using high resolution MS provided by Orbitrap technology. Subsequently, product ion spectra, precursor ion spectra, and MS3 spectra were recorded for structure elucidation of metabolites. While all investigated toxins were found to form various oxygenated metabolites during the oxidative phase I metabolism, those metabolites varied in the number of added oxygen atoms and in the number of individual isomers. No hints were obtained concerning the formation of glutathione adducts, and a conjugation with glucuronic acid was detected for AZA1 only.

  1. Evaluation of mass spectrometric data using principal component analysis for determination of the effects of organic lakes on protein binder identification.

    Science.gov (United States)

    Hrdlickova Kuckova, Stepanka; Rambouskova, Gabriela; Hynek, Radovan; Cejnar, Pavel; Oltrogge, Doris; Fuchs, Robert

    2015-11-01

    Matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry is commonly used for the identification of proteinaceous binders and their mixtures in artworks. The determination of protein binders is based on a comparison between the m/z values of tryptic peptides in the unknown sample and a reference one (egg, casein, animal glues etc.), but this method has greater potential to study changes due to ageing and the influence of organic/inorganic components on protein identification. However, it is necessary to then carry out statistical evaluation on the obtained data. Before now, it has been complicated to routinely convert the mass spectrometric data into a statistical programme, to extract and match the appropriate peaks. Only several 'homemade' computer programmes without user-friendly interfaces are available for these purposes. In this paper, we would like to present our completely new, publically available, non-commercial software, ms-alone and multiMS-toolbox, for principal component analyses of MALDI-TOF MS data for R software, and their application to the study of the influence of heterogeneous matrices (organic lakes) for protein identification. Using this new software, we determined the main factors that influence the protein analyses of artificially aged model mixtures of organic lakes and fish glue, prepared according to historical recipes that were used for book illumination, using MALDI-TOF peptide mass mapping. PMID:26505772

  2. Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid – a mass spectrometric study of SOA aging

    Directory of Open Access Journals (Sweden)

    L. Müller

    2011-07-01

    Full Text Available This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS. The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA, a known and very low volatile α-pinene SOA product, is formed from the oxidation of pinonic acid and that this oxidation takes place in the gas phase. This finding is confirmed by temperature-dependent aging experiments on whole SOA formed from α-pinene, in which the yield of MBTCA scales with the pinonic acid fraction in the gas phase. Based on the results, several feasible gas-phase radical mechanisms are discussed to explain the formation of MBTCA from OH-initiated pinonic acid oxidation.

  3. Quick identification of xanthine oxidase inhibitor and antioxidant from Erycibe obtusifolia by a drug discovery platform composed of multiple mass spectrometric platforms and thin-layer chromatography bioautography.

    Science.gov (United States)

    Chen, Zhiyong; Tao, Hongxun; Liao, Liping; Zhang, Zijia; Wang, Zhengtao

    2014-08-01

    As a final step of the purine metabolism process, xanthine oxidase catalyzes the oxidation of hypoxanthine and xanthine into uric acid. Our research has demonstrated that Erycibe obtusifolia has xanthine oxidase inhibitory properties. The purpose of this paper is to describe a new strategy based on a combination of multiple mass spectrometric platforms and thin-layer chromatography bioautography for effectively screening the xanthine oxidase inhibitory and antioxidant properties of E. obtusifolia. This strategy was accomplished through the following steps. (i) Separate the extract of E. obtusifolia into fractions by an autopurification system controlled by liquid chromatography with mass spectrometry. (ii) Determine the active fractions of E. obtusifolia by thin-layer chromatography bioautography. (iii) Identify the structure of the main active compounds with the information provided by direct analysis in real time mass spectrometry. (iv) Calculate the IC50 value of each compound against xanthine oxidase using high-performance liquid chromatography. Using the caulis of E. obtusifolia as the experimental material, seven target peaks were screened out as xanthine oxidase inhibitors or antioxidants. Our screening strategy allows for rapid analysis of small molecules with almost no sample preparation and can be completed within a week, making it a useful assay to identify unstable compounds and provide the empirical foundation for E. obtusifolia as a natural remedy for gout and oxidative-stress-related diseases.

  4. Mass Spectrometric Investigation of Silicon Extremely Enriched in (28)Si: From (28)SiF4 (Gas Phase IRMS) to (28)Si Crystals (MC-ICP-MS).

    Science.gov (United States)

    Pramann, Axel; Rienitz, Olaf

    2016-06-01

    A new generation of silicon crystals even further enriched in (28)Si (x((28)Si) > 0.999 98 mol/mol), recently produced by companies and institutes in Russia within the framework of a project initiated by PTB, were investigated with respect to their isotopic composition and molar mass M(Si). A modified isotope dilution mass spectrometric (IDMS) method treating the silicon as the matrix containing a so-called virtual element (VE) existing of the isotopes (29)Si and (30)Si solely and high resolution multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) were applied in combination. This method succeeds also when examining the new materials holding merely trace amounts of (29)Si (x((29)Si) ≈ 5 × 10(-6) mol/mol) and (30)Si (x((30)Si) ≈ 7 × 10(-7) mol/mol) extremely difficult to detect with lowest uncertainty. However, there is a need for validating the enrichment in (28)Si already in the precursor material of the final crystals, silicon tetrafluoride (SiF4) gas prior to crystal production. For that purpose, the isotopic composition of selected SiF4 samples was determined using a multicollector magnetic sector field gas-phase isotope ratio mass spectrometer. Contaminations of SiF4 by natural silicon due to storing and during the isotope ratio mass spectrometry (IRMS) measurements were observed and quantified. The respective MC-ICP-MS measurements of the corresponding crystal samples show-in contrast-several advantages compared to gas phase IRMS. M(Si) of the new crystals were determined to some extent with uncertainties urel(M) Si)) on the degree of enrichment in (28)Si. This leads to a reduction of urel(M(Si)) during the past decade by almost 3 orders of magnitude and thus further reduces the uncertainty of the Avogadro constant NA which is one of the preconditions for the redefinition of the SI unit kilogram.

  5. Mass Spectrometric Investigation of Silicon Extremely Enriched in (28)Si: From (28)SiF4 (Gas Phase IRMS) to (28)Si Crystals (MC-ICP-MS).

    Science.gov (United States)

    Pramann, Axel; Rienitz, Olaf

    2016-06-01

    A new generation of silicon crystals even further enriched in (28)Si (x((28)Si) > 0.999 98 mol/mol), recently produced by companies and institutes in Russia within the framework of a project initiated by PTB, were investigated with respect to their isotopic composition and molar mass M(Si). A modified isotope dilution mass spectrometric (IDMS) method treating the silicon as the matrix containing a so-called virtual element (VE) existing of the isotopes (29)Si and (30)Si solely and high resolution multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) were applied in combination. This method succeeds also when examining the new materials holding merely trace amounts of (29)Si (x((29)Si) ≈ 5 × 10(-6) mol/mol) and (30)Si (x((30)Si) ≈ 7 × 10(-7) mol/mol) extremely difficult to detect with lowest uncertainty. However, there is a need for validating the enrichment in (28)Si already in the precursor material of the final crystals, silicon tetrafluoride (SiF4) gas prior to crystal production. For that purpose, the isotopic composition of selected SiF4 samples was determined using a multicollector magnetic sector field gas-phase isotope ratio mass spectrometer. Contaminations of SiF4 by natural silicon due to storing and during the isotope ratio mass spectrometry (IRMS) measurements were observed and quantified. The respective MC-ICP-MS measurements of the corresponding crystal samples show-in contrast-several advantages compared to gas phase IRMS. M(Si) of the new crystals were determined to some extent with uncertainties urel(M) orders of magnitude and thus further reduces the uncertainty of the Avogadro constant NA which is one of the preconditions for the redefinition of the SI unit kilogram. PMID:27173726

  6. High Throughput In Situ DDA Analysis of Neuropeptides by Coupling Novel Multiplex Mass Spectrometric Imaging (MSI) with Gas-Phase Fractionation

    Science.gov (United States)

    OuYang, Chuanzi; Chen, Bingming; Li, Lingjun

    2015-12-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging (MSI) is a powerful tool to map the spatial distribution of biomolecules on tissue sections. Recent developments of hybrid MS instruments allow combination of different types of data acquisition by various mass analyzers into a single MSI analysis, which reduces experimental time and sample consumptions. Here, using the well-characterized crustacean nervous system as a test-bed, we explore the utility of high resolution and accurate mass (HRAM) MALDI Orbitrap platform for enhanced in situ characterization of the neuropeptidome with improved chemical information. Specifically, we report on a multiplex-MSI method, which combines HRAM MSI with data dependent acquisition (DDA) tandem MS analysis in a single experiment. This method enables simultaneous mapping of neuropeptide distribution, sequence validation, and novel neuropeptide discovery in crustacean neuronal tissues. To enhance the dynamic range and efficiency of in situ DDA, we introduced a novel approach of fractionating full m/z range into several sub-mass ranges and embedding the setup using the multiplex-DDA-MSI scan events to generate pseudo fractionation before MS/MS scans. The division of entire m/z into multiple segments of m/z sub-ranges for MS interrogation greatly decreased the complexity of molecular species from tissue samples and the heterogeneity of the distribution and variation of intensities of m/z peaks. By carefully optimizing the experimental conditions such as the dynamic exclusion, the multiplex-DDA-MSI approach demonstrates better performance with broader precursor coverage, less biased MS/MS scans towards high abundance molecules, and improved quality of tandem mass spectra for low intensity molecular species.

  7. Evaluation of the "added value" of SIMS: A mass spectrometric and spectroscopic study of an unusual Naples yellow oil paint reconstruction

    Science.gov (United States)

    Keune, Katrien; Hoogland, Frank; Boon, Jaap J.; Peggie, David; Higgitt, Catherine

    2009-07-01

    Naples yellow-containing oil paints aged under natural and artificial conditions were investigated as model systems to evaluate the potential of secondary ion mass spectrometry (SIMS) when used in combination with other mass spectrometric and spectroscopic analytical methods. Although the advantage of SIMS is the simultaneous detection of organic and inorganic components and their spatial distribution, the methodology has limitations in compound sensitivity and shows bias towards certain constituents. Gas chromatography-mass spectrometry (GC/MS) shows dicarboxylic fatty acids to be main components in the paint, but SIMS detects these compounds poorly. Electrospray ionisation mass spectrometry (ESI-MS) shows a broad range of glyceryl derivatives of mono- and dicarboxylic fatty acids (mono-, di- and triglyceride derivatives), while SIMS only detects the mono- and diglycerides of the monocarboxylic acids. Compared to SIMS, direct temperature-resolved mass spectrometry (DTMS) offers greater insight into how the various constituents are incorporated into the paint film, but SIMS data supports the information provided by Fourier transform infrared (FTIR) on metal soap formation. The surface sensitivity of SIMS is an advantage for probing paint constituent distributions and was exploited to examine variations in the composition of the top and bottom of a paint film, and the spatial correlation between metal and fatty acid composition in metal soap aggregates. Disadvantages of SIMS are the low yields and matrix dependency of the organic species in the paint matrix. Application of an ultra-thin gold coating overcomes this, and enhances the organic secondary ion yields leading to more accurate spatial distribution.

  8. Gas chromatography-mass spectrometric analysis of bonded long chain fatty acids in a single zebrafish egg by ultrasound-assisted one-step transmethylation and extraction

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianjian; Yue Yingxia; Li Tingting; Hu Xuejiao [Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079 (China); Zhong Hongying, E-mail: hyzhong@mail.ccnu.edu.cn [Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079 (China)

    2009-09-21

    Changes in the level of lipid composition in a single zebrafish egg have been involved in biological responses to chemical exposures. In this paper, an one-step transmethylation of lipids and simultaneous extraction of resultant fatty acid methyl esters followed by gas chromatography-mass spectrometric analysis was developed for the identification of bonded long chain fatty acids in a single zebrafish egg. The efficiency of transmethylation under different experimental conditions has been investigated. Dried egg homogenates were directly mixed with either 0.5 M NaOH or 1% H{sub 2}SO{sub 4} or 4% HCl solution of methanol and then an n-hexane solution was added on the top. Ultrasonication of this immiscible liquid-liquid-solid system produces high velocity impacts between solid particles and liquid phases and thus promotes mass transfer among phases. It was demonstrated that ultrasound irradiation has strong effect on the alkaline-catalyzed transmethylation of lipids but cannot significantly change the acid-catalyzed transmethylation of lipids. With the aid of ultrasonication, transmethylation can be combined with simultaneous extraction of the resultant fatty acid methyl esters into n-hexane phase. This approach simplifies the sample preparation procedure, shortens the reaction time but improves the efficiency of the transmethylation of lipids and reduces sample losses, especially for small size samples. It has been applied to determine bonded fatty acids in a single zebrafish egg. In total, 28 fatty acids from a single zebrafish egg have been identified reproducibly.

  9. Gas chromatography-mass spectrometric analysis of bonded long chain fatty acids in a single zebrafish egg by ultrasound-assisted one-step transmethylation and extraction

    International Nuclear Information System (INIS)

    Changes in the level of lipid composition in a single zebrafish egg have been involved in biological responses to chemical exposures. In this paper, an one-step transmethylation of lipids and simultaneous extraction of resultant fatty acid methyl esters followed by gas chromatography-mass spectrometric analysis was developed for the identification of bonded long chain fatty acids in a single zebrafish egg. The efficiency of transmethylation under different experimental conditions has been investigated. Dried egg homogenates were directly mixed with either 0.5 M NaOH or 1% H2SO4 or 4% HCl solution of methanol and then an n-hexane solution was added on the top. Ultrasonication of this immiscible liquid-liquid-solid system produces high velocity impacts between solid particles and liquid phases and thus promotes mass transfer among phases. It was demonstrated that ultrasound irradiation has strong effect on the alkaline-catalyzed transmethylation of lipids but cannot significantly change the acid-catalyzed transmethylation of lipids. With the aid of ultrasonication, transmethylation can be combined with simultaneous extraction of the resultant fatty acid methyl esters into n-hexane phase. This approach simplifies the sample preparation procedure, shortens the reaction time but improves the efficiency of the transmethylation of lipids and reduces sample losses, especially for small size samples. It has been applied to determine bonded fatty acids in a single zebrafish egg. In total, 28 fatty acids from a single zebrafish egg have been identified reproducibly.

  10. [Determination of nine estrogenic steroids in milk using matrix solid phase dispersion-ultra performance liquid chromatography with mass spectrometric detector].

    Science.gov (United States)

    Liu, Hongcheng; Li, Ning; Lin, Tao; Shao, Jinliang; Li, Qiwan

    2015-11-01

    An analytical method for the multiresidue determination of nine estrogenic steroids in milk was developed by modified matrix solid phase dispersion (MSPD) purification and ultra performance liquid chromatography (UPLC) with mass spectrometric detector (MSD). The sensitivity and accuracy of MSD were better than that of ultraviolet detector. In comparison with traditional mass spectrometry, the merits of MSD were simpler in operation and shorter in starting time (5 min). The results showed that the limits of detection of the compounds with nucleophilic substitution were high in positive ion mode of MSD and were easily affected by environmental conditions. The matrix effects of milk samples reduced from 84%-160% to 80%-121% after MSPD purification. The intraday precision and interday precision of the nine estrogenic steroids were 0.87%-1.78% and 1.82%-3.79%, respectively. The average recoveries were 68.7%-94.7%, and the relative standard deviations (RSDs) were less than 10%. The limits of detection (LODs) were 0.5-10 μg/kg. The limits of quantification (LOQ) were 2-20 μg/kg. PMID:26939362

  11. Determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using radiochemical separation combined with radiometric and mass spectrometric measurements.

    Science.gov (United States)

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin; Pan, Shaoming; Roos, Per

    2014-02-01

    This paper reports an analytical method for the determination of plutonium isotopes ((238)Pu, (239)Pu, (240)Pu, (241)Pu) in environmental samples using anion exchange chromatography in combination with extraction chromatography for chemical separation of Pu. Both radiometric methods (liquid scintillation counting and alpha spectrometry) and inductively coupled plasma mass spectrometry (ICP-MS) were applied for the measurement of plutonium isotopes. The decontamination factors for uranium were significantly improved up to 7.5 × 10(5) for 20 g soil compared to the level reported in the literature, this is critical for the measurement of plutonium isotopes using mass spectrometric technique. Although the chemical yield of Pu in the entire procedure is about 55%, the analytical results of IAEA soil 6 and IAEA-367 in this work are in a good agreement with the values reported in the literature or reference values, revealing that the developed method for plutonium determination in environmental samples is reliable. The measurement results of (239+240)Pu by alpha spectrometry agreed very well with the sum of (239)Pu and (240)Pu measured by ICP-MS. ICP-MS can not only measure (239)Pu and (240)Pu separately but also (241)Pu. However, it is impossible to measure (238)Pu using ICP-MS in environmental samples even a decontamination factor as high as 10(6) for uranium was obtained by chemical separation. PMID:24401459

  12. Determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using radiochemical separation combined with radiometric and mass spectrometric measurements.

    Science.gov (United States)

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin; Pan, Shaoming; Roos, Per

    2014-02-01

    This paper reports an analytical method for the determination of plutonium isotopes ((238)Pu, (239)Pu, (240)Pu, (241)Pu) in environmental samples using anion exchange chromatography in combination with extraction chromatography for chemical separation of Pu. Both radiometric methods (liquid scintillation counting and alpha spectrometry) and inductively coupled plasma mass spectrometry (ICP-MS) were applied for the measurement of plutonium isotopes. The decontamination factors for uranium were significantly improved up to 7.5 × 10(5) for 20 g soil compared to the level reported in the literature, this is critical for the measurement of plutonium isotopes using mass spectrometric technique. Although the chemical yield of Pu in the entire procedure is about 55%, the analytical results of IAEA soil 6 and IAEA-367 in this work are in a good agreement with the values reported in the literature or reference values, revealing that the developed method for plutonium determination in environmental samples is reliable. The measurement results of (239+240)Pu by alpha spectrometry agreed very well with the sum of (239)Pu and (240)Pu measured by ICP-MS. ICP-MS can not only measure (239)Pu and (240)Pu separately but also (241)Pu. However, it is impossible to measure (238)Pu using ICP-MS in environmental samples even a decontamination factor as high as 10(6) for uranium was obtained by chemical separation.

  13. Parallel Workflow for High-Throughput (>1,000 Samples/Day) Quantitative Analysis of Human Insulin-Like Growth Factor 1 Using Mass Spectrometric Immunoassay

    Science.gov (United States)

    Oran, Paul E.; Trenchevska, Olgica; Nedelkov, Dobrin; Borges, Chad R.; Schaab, Matthew R.; Rehder, Douglas S.; Jarvis, Jason W.; Sherma, Nisha D.; Shen, Luhui; Krastins, Bryan; Lopez, Mary F.; Schwenke, Dawn C.; Reaven, Peter D.; Nelson, Randall W.

    2014-01-01

    Insulin-like growth factor 1 (IGF1) is an important biomarker for the management of growth hormone disorders. Recently there has been rising interest in deploying mass spectrometric (MS) methods of detection for measuring IGF1. However, widespread clinical adoption of any MS-based IGF1 assay will require increased throughput and speed to justify the costs of analyses, and robust industrial platforms that are reproducible across laboratories. Presented here is an MS-based quantitative IGF1 assay with performance rating of >1,000 samples/day, and a capability of quantifying IGF1 point mutations and posttranslational modifications. The throughput of the IGF1 mass spectrometric immunoassay (MSIA) benefited from a simplified sample preparation step, IGF1 immunocapture in a tip format, and high-throughput MALDI-TOF MS analysis. The Limit of Detection and Limit of Quantification of the resulting assay were 1.5 μg/L and 5 μg/L, respectively, with intra- and inter-assay precision CVs of less than 10%, and good linearity and recovery characteristics. The IGF1 MSIA was benchmarked against commercially available IGF1 ELISA via Bland-Altman method comparison test, resulting in a slight positive bias of 16%. The IGF1 MSIA was employed in an optimized parallel workflow utilizing two pipetting robots and MALDI-TOF-MS instruments synced into one-hour phases of sample preparation, extraction and MSIA pipette tip elution, MS data collection, and data processing. Using this workflow, high-throughput IGF1 quantification of 1,054 human samples was achieved in approximately 9 hours. This rate of assaying is a significant improvement over existing MS-based IGF1 assays, and is on par with that of the enzyme-based immunoassays. Furthermore, a mutation was detected in ∼1% of the samples (SNP: rs17884626, creating an A→T substitution at position 67 of the IGF1), demonstrating the capability of IGF1 MSIA to detect point mutations and posttranslational modifications. PMID:24664114

  14. Parallel workflow for high-throughput (>1,000 samples/day quantitative analysis of human insulin-like growth factor 1 using mass spectrometric immunoassay.

    Directory of Open Access Journals (Sweden)

    Paul E Oran

    Full Text Available Insulin-like growth factor 1 (IGF1 is an important biomarker for the management of growth hormone disorders. Recently there has been rising interest in deploying mass spectrometric (MS methods of detection for measuring IGF1. However, widespread clinical adoption of any MS-based IGF1 assay will require increased throughput and speed to justify the costs of analyses, and robust industrial platforms that are reproducible across laboratories. Presented here is an MS-based quantitative IGF1 assay with performance rating of >1,000 samples/day, and a capability of quantifying IGF1 point mutations and posttranslational modifications. The throughput of the IGF1 mass spectrometric immunoassay (MSIA benefited from a simplified sample preparation step, IGF1 immunocapture in a tip format, and high-throughput MALDI-TOF MS analysis. The Limit of Detection and Limit of Quantification of the resulting assay were 1.5 μg/L and 5 μg/L, respectively, with intra- and inter-assay precision CVs of less than 10%, and good linearity and recovery characteristics. The IGF1 MSIA was benchmarked against commercially available IGF1 ELISA via Bland-Altman method comparison test, resulting in a slight positive bias of 16%. The IGF1 MSIA was employed in an optimized parallel workflow utilizing two pipetting robots and MALDI-TOF-MS instruments synced into one-hour phases of sample preparation, extraction and MSIA pipette tip elution, MS data collection, and data processing. Using this workflow, high-throughput IGF1 quantification of 1,054 human samples was achieved in approximately 9 hours. This rate of assaying is a significant improvement over existing MS-based IGF1 assays, and is on par with that of the enzyme-based immunoassays. Furthermore, a mutation was detected in ∼1% of the samples (SNP: rs17884626, creating an A→T substitution at position 67 of the IGF1, demonstrating the capability of IGF1 MSIA to detect point mutations and posttranslational modifications.

  15. Mass-spectrometric identification of primary biological particle markers and application to pristine submicron aerosol measurements in Amazonia

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2011-11-01

    Full Text Available The detection of primary biological material in submicron aerosol by means of thermal desorption/electron impact ionization aerosol mass spectrometry was investigated. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker fragments were identified. The intensity of the marker signals relative to the total organic mass spectrum allows for an estimation of the content of primary biological material in ambient organic aerosol. The developed method was applied to mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker fragments places upper limits of 7.5% for amino acids and 5.6% for carbohydrates on the contribution of primary biological aerosol particles (PBAP to the submicron organic aerosol mass concentration during this time period. Upper limits for the absolute submicron concentrations for both compound classes range from 0.01 to 0.1 μg m−3. Carbohydrates and proteins (composed of amino acids make up for about two thirds of the dry mass of a biological cell. Thus, our findings suggest an upper limit for the PBAP mass fraction of about 20% to the submicron organic aerosol measured in Amazonia during AMAZE-08.

  16. Development of a high-speed MALDI-triple quadrupole mass spectrometric method for the determination of 3,4-methylenedioxymethamphetamine (MDMA) in oral fluid.

    Science.gov (United States)

    Poetzsch, Michael; Steuer, Andrea E; Hysek, Cedric M; Liechti, Matthias E; Kraemer, Thomas

    2016-02-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is still a widely used illicit designer drug and its detection in different matrices is of major importance for forensic purposes (e.g. driving under the influence) as well as for workplace drug testing or abstinence control. Established analytical methods for the determination of MDMA are mainly employing high performance liquid chromatography (HPLC) or gas chromatography (GC) coupled to mass spectrometric detection. Matrix assisted laser desorption/ionization-triple quadrupole-tandem mass spectrometry (MALDI-QqQ-MS/MS) is so far rarely used in forensics and offers an ultrafast high-throughput platform. The Quantisal™ Oral Fluid Collection Device was used for sample collection. After addition of the deuterated internal standard and a carbonate buffer (0.75 M Na2 CO3 ), oral fluid samples were liquid-liquid extracted (ButOAc/EtOAc, 1:1). As little as 1 microlitre of a mixture of this extract and the MALDI matrix (alpha-cyano-4-hydroxycinnamic acid) was spotted onto the MALDI plate and could directly be analyzed. With MALDI omitting chromatographic separation, very short analysis times of about 10 s per sample were possible. The method was developed and validated according to international guidelines including specificity, recovery, matrix effects, accuracy and precision, stabilities and limit of quantification. All validation criteria were fulfilled except for ion suppression/enhancement. Comparison with a routine liquid chromatography-tandem mass spectrometry (LC-MS/MS) method showed good agreement of the results. Applicability of the method was shown by analyzing about 250 oral fluid samples collected after controlled administration of 125 mg MDMA in a pharmacokinetic study. The whole lot of samples could be analyzed in less than 1 h, proving the ultra-high-speed of the method. PMID:25990956

  17. Ampicillin/penicillin-binding protein interactions as a model drug-target system to optimize affinity pull-down and mass spectrometric strategies for target and pathway identification.

    Science.gov (United States)

    von Rechenberg, Moritz; Blake, Brian Kelly; Ho, Yew-Seng J; Zhen, Yuejun; Chepanoske, Cindy Lou; Richardson, Bonnie E; Xu, Nafei; Kery, Vladimir

    2005-05-01

    The identification and validation of the targets of active compounds identified in cell-based assays is an important step in preclinical drug development. New analytical approaches that combine drug affinity pull-down assays with mass spectrometry (MS) could lead to the identification of new targets and druggable pathways. In this work, we investigate a drug-target system consisting of ampicillin- and penicillin-binding proteins (PBPs) to evaluate and compare different amino-reactive resins for the immobilization of the affinity compound and mass spectrometric methods to identify proteins from drug affinity pull-down assays. First, ampicillin was immobilized onto various amino-reactive resins, which were compared in the ampicillin-PBP model with respect to their nonspecific binding of proteins from an Escherichia coli membrane extract. Dynal M-270 magnetic beads were chosen to further study the system as a model for capturing and identifying the targets of ampicillin, PBPs that were specifically and covalently bound to the immobilized ampicillin. The PBPs were identified, after in situ digestion of proteins bound to ampicillin directly on the beads, by using either one-dimensional (1-D) or two-dimensional (2-D) liquid chromatography (LC) separation techniques followed by tandem mass spectrometry (MS/MS) analysis. Alternatively, an elution with N-lauroylsarcosine (sarcosyl) from the ampicillin beads followed by in situ digestion and 2-D LC-MS/MS analysis identified proteins potentially interacting noncovalently with the PBPs or the ampicillin. The in situ approach required only little time, resources, and sample for the analysis. The combination of drug affinity pull-down assays with in situ digestion and 2-D LC-MS/MS analysis is a useful tool in obtaining complex information about a primary drug target as well as its protein interactors. PMID:15761956

  18. Identification of Polish cochineal (Porphyrophora polonica L.) in historical textiles by high-performance liquid chromatography coupled with spectrophotometric and tandem mass spectrometric detection.

    Science.gov (United States)

    Lech, Katarzyna; Jarosz, Maciej

    2016-05-01

    The present work reports a method for identification of Polish cochineal (Porphyrophora polonica L.) in historical fabrics by the use of high-performance liquid chromatography coupled with diode array and tandem mass spectrometric detection with electrospray ionization (HPLC-DAD-ESI MS/MS). This hyphened technique allows detection and identification of 16 new minor colorants present in the discussed scale insect (including two previously observed by Wouters and Verhecken (Ann Soc Entomol Fr. 1989;25:393-410), but specified only as compounds of unknown structures) that do not occur (e.g., in American cochineal). The MS/MS experiments, complemented with UV-VIS data, enable identification of mono- and di-, C- and O-hexosides of kermesic and flavokermesic acids or their derivatives. The present paper introduces a fingerprint of color compounds present in Polish cochineal and defines them, particularly pp6 (ppI, O-hexoside of flavokermesic acid), as its markers allow distinguishing of Polish-cochineal reds from the American ones. Usefulness of the selected set of markers for identification of Polish cochineal has been demonstrated in the examination of textiles from the collection of the National Museum in Warsaw using the multiple reaction monitoring (MRM) method, originally elaborated on the basis of this study. PMID:26935929

  19. Simple field-based automated dispersive liquid-liquid microextraction of trace level phthalate esters in natural waters with gas chromatography and mass spectrometric analysis.

    Science.gov (United States)

    Leng, Geng; Chen, Wenjin; Wang, Yong

    2016-09-01

    A small, simple, and field-based automated dispersive liquid-liquid microextraction method followed by gas chromatography mass spectrometric analysis was developed for trace level phthalate esters analysis in natural waters. With a single syringe pump that is coupled with a multiposition valve, the whole extraction procedure including cleaning, sampling, mixing of extractant and disperser solvents, extraction, phase separation, and analytes collection was carried out in a totally automated way with a sample throughput of 21 h(-1) . Key factors, such as type and ratio of the extractant and disperser solvent, aspiration flow rate, extraction time, and matrix effect, were thoroughly investigated. Under the optimum conditions, linearity was found in the range from 0.03 to 60 μg/L. Limits of detection ranged from 0.0015 to 0.003 μg/L. Enrichment factors were in a range of 106-141. Reproducibility and recoveries were assessed by testing a series of three natural water samples that were spiked with different concentration levels. Finally, the proposed method was successfully applied in analysis of real surface waters. The developed system is inexpensive, light (2.6 kg), simple to use, applicable in the field, with high sample throughput, and sensitive enough for trace level phthalate esters analysis in natural waters.

  20. Liquid chromatography-tandem mass spectrometric methods for the determination of spinosad, thiacloprid and pyridalyl in spring onions and estimation of their pre-harvest interval values.

    Science.gov (United States)

    Dasenaki, Marilena E; Bletsou, Anna A; Hanafi, Ahmad H; Thomaidis, Nikolaos S

    2016-12-15

    Two liquid chromatography-tandem mass spectrometric methods were developed and validated to determine spinosyn A and D, thiacloprid and pyridalyl in spring onions cultivated under Egyptian field conditions. The degradation rates, the pre-harvest interval (PHI) values and the half-life values of the three pesticides were estimated. QuEChERS was used for sample preparation and the separation was performed on an X-Bridge C18 column with ACN-formic acid 0.1% as the mobile phase. Linear range, method detection limits (MDLs), precision, recovery and matrix effects were estimated. The multi-residue MDLs ranged from 0.02μg/kg (spinosyn A & D) to 0.05μg/kg for pyridalyl. All the investigated pesticides showed high degradation rates. For spinosad the half-life value was 1.2days, for thiacloprid it reached 2.2days and for pyridalyl 4.4days. Furthermore, the calculated PHI values, according to the maximum residue levels set by the EU, were 0days for spinosad, 9.8days for thiacloprid and 39.4days for pyridalyl. PMID:27451196

  1. Simple field-based automated dispersive liquid-liquid microextraction of trace level phthalate esters in natural waters with gas chromatography and mass spectrometric analysis.

    Science.gov (United States)

    Leng, Geng; Chen, Wenjin; Wang, Yong

    2016-09-01

    A small, simple, and field-based automated dispersive liquid-liquid microextraction method followed by gas chromatography mass spectrometric analysis was developed for trace level phthalate esters analysis in natural waters. With a single syringe pump that is coupled with a multiposition valve, the whole extraction procedure including cleaning, sampling, mixing of extractant and disperser solvents, extraction, phase separation, and analytes collection was carried out in a totally automated way with a sample throughput of 21 h(-1) . Key factors, such as type and ratio of the extractant and disperser solvent, aspiration flow rate, extraction time, and matrix effect, were thoroughly investigated. Under the optimum conditions, linearity was found in the range from 0.03 to 60 μg/L. Limits of detection ranged from 0.0015 to 0.003 μg/L. Enrichment factors were in a range of 106-141. Reproducibility and recoveries were assessed by testing a series of three natural water samples that were spiked with different concentration levels. Finally, the proposed method was successfully applied in analysis of real surface waters. The developed system is inexpensive, light (2.6 kg), simple to use, applicable in the field, with high sample throughput, and sensitive enough for trace level phthalate esters analysis in natural waters. PMID:27377176

  2. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, S. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Otto, M. [TU Bergakademie Freiberg (TU BAF), Institute for Analytical Chemistry, Leipziger Str. 29, D - 09599 Freiberg (Germany)], E-mail: matthias.otto@chemie.tu-freiberg.de; Niewoehner, L.; Barth, M. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Brozek-Mucha, Z. [Instytut Ekspertyz Sadowych (IES), Westerplatte St. 9, PL - 31-033 Krakow (Poland); Biegstraaten, J. [Nederlands Forensisch Instituut (NFI), Fysische Technologie, Laan van Ypenburg 6, NL-2497 GB Den Haag (Netherlands); Horvath, R. [Kriminalisticky a Expertizny Ustav (KEU PZ), Institute of Forensic Science, Sklabinska 1, SK - 812 72 Bratislava (Slovakia)

    2007-09-15

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  3. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    International Nuclear Information System (INIS)

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification

  4. A method of test for residual isophorone diisocyanate trimer in new polyester-polyurethane coatings on light metal packaging using liquid chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Driffield, Malcolm; Bradley, Emma L; Castle, Laurence

    2007-02-01

    A method of test for residual isophorone diisocyanate (IPDI) trimer in experimental formulation polyester-polyurethane (PEPU) thermoset coatings on metal food packaging is described. The method involves extraction of coated panels using acetonitrile containing dibutylamine for concurrent derivatisation, and then high performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection (LC-MS/MS). Single laboratory validation was carried out using three different experimental PEPU-based coatings. The calibrations were linear, the analytical recovery was good, no interferences were seen, and substance identification criteria were met. The detection limit of the method is around 0.02 micro g/100 cm(2) of coating, which for a typical sized can and assuming complete migration of any residual IPDI trimer, corresponds to about 0.2 micro g/kg food or beverage. Separate studies indicated that, even if migration occurred at such low levels, the IPDI trimer would not be expected to persist in canned aqueous or fatty foodstuffs as it would hydrolyse to the corresponding aliphatic amine or react with food components to destroy the isocyanate moiety. The method of test developed here for residual IPDI trimer in thermoset polyester-polyurethane coatings should prove to be a valuable tool for investigating the cure kinetics of these novel coatings and help to guide the development of enhanced formulations.

  5. Automated multi-plug filtration cleanup for liquid chromatographic-tandem mass spectrometric pesticide multi-residue analysis in representative crop commodities.

    Science.gov (United States)

    Qin, Yuhong; Zhang, Jingru; Zhang, Yuan; Li, Fangbing; Han, Yongtao; Zou, Nan; Xu, Haowei; Qian, Meiyuan; Pan, Canping

    2016-09-01

    An automated multi-plug filtration cleanup (m-PFC) method on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts was developed. The automatic device was aimed to reduce labor-consuming manual operation workload in the cleanup steps. It could control the volume and the speed of pulling and pushing cycles accurately. In this work, m-PFC was based on multi-walled carbon nanotubes (MWCNTs) mixed with other sorbents and anhydrous magnesium sulfate (MgSO4) in a packed tip for analysis of pesticide multi-residues in crop commodities followed by liquid chromatography with tandem mass spectrometric (LC-MS/MS) detection. It was validated by analyzing 25 pesticides in six representative matrices spiked at two concentration levels of 10 and 100μg/kg. Salts, sorbents, m-PFC procedure, automated pulling and pushing volume, automated pulling speed, and pushing speed for each matrix were optimized. After optimization, two general automated m-PFC methods were introduced to relatively simple (apple, citrus fruit, peanut) and relatively complex (spinach, leek, green tea) matrices. Spike recoveries were within 83 and 108% and 1-14% RSD for most analytes in the tested matrices. Matrix-matched calibrations were performed with the coefficients of determination >0.997 between concentration levels of 10 and 1000μg/kg. The developed method was successfully applied to the determination of pesticide residues in market samples.

  6. A liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric method for the determination of organosulfur compounds in petroleum asphalt cements.

    Science.gov (United States)

    da Silveira, Géssica Domingos; Faccin, Henrique; Claussen, Luis; Goularte, Rayane Bueno; Do Nascimento, Paulo C; Bohrer, Denise; Cravo, Margareth; Leite, Leni F M; de Carvalho, Leandro Machado

    2016-07-29

    We present a sensitive liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric (UHPLC-APPI-MS/MS) method for the determination of selected organosulfur compounds in Brazilian asphalt cements. It was possible to detect 14 organosulfur compounds of different classes where sulfoxides and sulfones presented higher sensibility in ionization than thiophenes and aromatic sulfides. A dopant-assisted APPI method was also tested, however, when chromatographic flow rate was optimized a decrease in signal was observed for all compounds. PAHs were tested and ruled out as possible interfering compounds and the matrix effect of asphalt cements was within an acceptable range for the quantification of organosulfur compounds. The proposed method was found to have satisfactory linearity and accuracy with recoveries between 83.85 and 110.28% for thianaphthene and 3-methylbenzothiophene, respectively. Therefore, the method allowed the characterization of organosulfur compounds in Brazilian asphalt cements and demonstrated changes in the amount quantified in asphaltenic and maltenic fractions after the RTFOT+SUNTEST aging process. PMID:27342135

  7. Validation of method for determination of different classes of pesticides in aqueous samples by dispersive liquid-liquid microextraction with liquid chromatography-tandem mass spectrometric detection.

    Science.gov (United States)

    Caldas, Sergiane Souza; Costa, Fabiane Pinho; Primel, Ednei Gilberto

    2010-04-14

    In this study, a simple, rapid and efficient method has been developed for the extraction and preconcentration of different classes of pesticides, carbofuran (insecticide), clomazone (herbicide) and tebuconazole (fungicide) in aqueous samples by dispersive liquid-liquid microextraction (DLLME) coupled with liquid chromatography-tandem mass spectrometric detection. Some experimental parameters that influence the extraction efficiency, such as the type and volume of the disperser solvents and extraction solvents, extraction time, speed of centrifugation, pH and addition of salt were examined and optimized. Under the optimum conditions, the recoveries of pesticides in water at spiking levels between 0.02 and 2.0 microg L(-1) ranged from 62.7% to 120.0%. The relative standard deviations varied between 1.9% and 9.1% (n=3). The limits of quantification of the method considering a 50-fold preconcentration step were 0.02 microg L(-1). The linearity of the method ranged from 1.0 to 1000 microg L(-1) for all compounds, with correlation coefficients varying from 0.9982 to 0.9992. Results show that the method we propose can meet the requirements for the determination of pesticides in water samples. The comparison of this method with solid-phase extraction indicates that DLLME is a simple, fast, and low-cost method for the determination of pesticides in natural waters.

  8. A method of test for residual isophorone diisocyanate trimer in new polyester-polyurethane coatings on light metal packaging using liquid chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Driffield, Malcolm; Bradley, Emma L; Castle, Laurence

    2007-02-01

    A method of test for residual isophorone diisocyanate (IPDI) trimer in experimental formulation polyester-polyurethane (PEPU) thermoset coatings on metal food packaging is described. The method involves extraction of coated panels using acetonitrile containing dibutylamine for concurrent derivatisation, and then high performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection (LC-MS/MS). Single laboratory validation was carried out using three different experimental PEPU-based coatings. The calibrations were linear, the analytical recovery was good, no interferences were seen, and substance identification criteria were met. The detection limit of the method is around 0.02 micro g/100 cm(2) of coating, which for a typical sized can and assuming complete migration of any residual IPDI trimer, corresponds to about 0.2 micro g/kg food or beverage. Separate studies indicated that, even if migration occurred at such low levels, the IPDI trimer would not be expected to persist in canned aqueous or fatty foodstuffs as it would hydrolyse to the corresponding aliphatic amine or react with food components to destroy the isocyanate moiety. The method of test developed here for residual IPDI trimer in thermoset polyester-polyurethane coatings should prove to be a valuable tool for investigating the cure kinetics of these novel coatings and help to guide the development of enhanced formulations. PMID:17178416

  9. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    Science.gov (United States)

    Steffen, S.; Otto, M.; Niewoehner, L.; Barth, M.; Bro¿żek-Mucha, Z.; Biegstraaten, J.; Horváth, R.

    2007-09-01

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  10. Application of comprehensive two-dimensional gas chromatography with mass spectrometric detection for the analysis of selected drug residues in wastewater and surface water

    Institute of Scientific and Technical Information of China (English)

    Petr Lacina; Ludmila Mravcová; Milada Vávrová

    2013-01-01

    Pharmaceutical residues have become tightly controlled environmental contaminants in recent years,due to their increasing concentration in environmental components.This is mainly caused by their high level of production and everyday consumption.Therefore there is a need to apply new and sufficiently sensitive analytical methods,which can detect the presence of these contaminants even in very low concentrations.This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues,mainly from the group of non-steroidal anti-iaffammatory drugs (salicylic acid,acetylsalicylic acid,clofibric acid,ibuprofen,acetaminophen,caffeine,naproxen,mefenamic acid,ketoprofen,and dicofenac),in wastewaters and surface waters.This analytical method is based on solid phase extraction,derivatization by N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection (GCxGC-TOF MS).Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix.The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice,Czech Republic.The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of μg/L in wastewater.

  11. Timing of Holocene sea-level highstands by mass spectro-metric U-series ages of a coral reef from Leizhou Peninsula,South China Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Systematic mass spectrometric 230Th ages are reported for a Porites coral reef terrace from Dengloujiao,Leizhou Peninsula, South China Sea. Seven episodes of coral growth were recognized in this terrace: 7125±96, 6764±29,5826±37, 5006±54, 2543±24, 1915±15, and 1513±22 calendar years before present (cal. aBP). 50% of the coral age population fall between 7200 and 6600 cal. aBP, marking post-glacial stabdization of global sea level. Considering the facts that ( i ) Dengloujiao reef fiat was measured at 1.6-2.5m above modern tidal datum plane; (ii) modern Porites corals in the South China Sea are living at least ~1 m below the modern tidal datum plane; (iii) the top 20-30 cm of the reef was eroded; and (iv) crustal subsidence in the region since mid-Holocene was negligible, we conclude that the above age groups record at least two major periods (7200-5000 and 2500-1500 cal. aBP) of high sea-level at least 2.9-3.8 m above the present-day level.

  12. Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Roos, Per

    2008-01-01

    spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer...

  13. Development of liquid chromatography mass spectrometric methods for quantification of metabolites from cellular level to clinical biomarkers

    OpenAIRE

    Tohmola, Niina

    2015-01-01

    Metabolites are low molecular weight compounds participating in different functions of cellular systems. Metabolites can be used as diagnostic biomarkers for numerous diseases. Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a powerful tool in quantification of metabolites from various sample matrices. Good sensitivity and specificity are the main benefits of the technique. Mass spectrometry is commonly used in industry, drug research and clinical diagnostics. Extensive validatio...

  14. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    OpenAIRE

    Chang Young Lee; Yi Fan; Rubakhin, Stanislav S.; Sook Yoon; Sweedler, Jonathan V.

    2016-01-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia...

  15. High Precision Thermal Ionization Mass Spectrometric Dating of Corals and Its Application to Paleo—Environmental Study

    Institute of Scientific and Technical Information of China (English)

    王兆荣; 张兆峰; 等

    2001-01-01

    Global change has become a hot spot in Quaternary geology,and high-precision,high-sensitivity dating is also an urgent problem which needs to be solved.This paper presents some achievements in U-servies dating of marine corals by thermal ionization mass spectrometry (TIMS) and its application to the study of paleo-environments.Recently,coral samples were determined for their ages on a MAT-262 mass spectrometer and satisfactory results have been obtained.

  16. High Precision Thermal Ionization Mass Spectrometric Dating of Corals and Its Application to Paleo-Environmental Study

    Institute of Scientific and Technical Information of China (English)

    王兆荣; 张兆峰; 彭子成; 马志邦

    2001-01-01

    Global change has become a hot spot in Quaternary geology, and high-precision,high-sensitivity dating is also an urgent problem which needs to be solved. This paper presents some achievements in U-series dating of marine corals by thermal ionization mass spectrometry (TIMS) and its application to the study of paleo-environments. Recently, coral samples were determined for their ages on a MAT-262 mass spectrometer and satisfactory results have been obtained.

  17. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Aluminum oxide pellets are used in a reactor core as filler or spacers within fuel, burnable poison, or control rods. In order to be suitable for this purpose, the material must meet certain criteria for impurity content. The test methods in the standard are designed to show whether or not a given material meets these specifications. The following analytical procedures are described in detail: boron by titrimetry; separation of boron by mass spectrometry; isotopic composition by mass spectrometry; separation of halides by pyrohydrolysis; fluoride by ion-selective electrode; chloride, bromide, and iodide by amperometric microtitrimetry; trace elements by emission spectroscopy. (JMT)

  18. A liquid chromatography-tandem mass spectrometric method for quantitative determination of native 5-methyltetrahydrofolate and its polyglutamyl derivatives in raw vegetables.

    Science.gov (United States)

    Wang, Chao; Riedl, Ken M; Schwartz, Steven J

    2010-11-01

    Folate deficiency is a prevalent phenomenon worldwide especially in underprivileged countries. Polyglutamyl 5-methyltetrahydrofolate (5MTHF) species are the naturally occurring principle folate in store-bought vegetables. Here we report a simple and complete extraction method for the determination of native polyglutamyl 5-methyltetrahydrofolate in vegetables using high performance liquid chromatography with tandem mass spectrometric detection (HPLC-MS/MS). Coarsely chopped samples (18 different vegetables) were steamed to inactivate glutamylase enzymes and liberate folate from binding proteins and extracted in a reducing buffer with (13)C(5) 5MTHF stable isotope added as internal standard. The polyglutamyl 5-methyltetrahydrofolate species were separated in 9 min on a C(18) column using a reversed phase system. HPLC eluate was interfaced with a triple quadrupole mass spectrometer operated in electrospray positive mode. The respective pseudomolecular cation of each polyglutamyl 5-methyltetrahydrofolate species was selected for fragmentation to a common daughter ion for detection. We quantitated polyglutamyl 5-methyltetrahydrofolate in store-bought vegetables from families Brassicaceae, Asteraceae and Amaranthaceae (including mustard greens, romaine lettuce and Swiss chard) of which most have not been quantitated previously. Most vegetables from Asteraceae and those from Amaranthaceae contained similar amounts of monoglutamyl 5MTHF and polyglutamyl 5MTHF while Brassicaceae were dominated by polyglutamyls and endive species (Asteraceae) contained mainly monoglutamyl 5MTHF. The precision of the method for the various polyglutamyl 5-methyltetrahydrofolate forms was 1-9% RSD, recovery 84-91%, limit of detection 64-658 fmol and limit of quantitation 193-1994 fmol. Herein we describe a rapid, sensitive and selective HPLC-MS/MS technique to quantitate polyglutamyl 5-methyltetrahydrofolate species. This method may be suitable for analyzing the polyglutamyl 5

  19. Bioprospecting of microalgae: Proper extraction followed by high performance liquid chromatographic-high resolution mass spectrometric fingerprinting as key tools for successful metabolom characterization.

    Science.gov (United States)

    Stranska-Zachariasova, Milena; Kastanek, Petr; Dzuman, Zbynek; Rubert, Josep; Godula, Michal; Hajslova, Jana

    2016-03-15

    Currently, the interest in microalgae as a source of biologically active components exploitable as supplementary ingredients to food/feed or in cosmetics continues to increase. Existing research mainly aims to focus on revealing and recovering the rare, cost competitive components of the algae metabolom. Because these components could be of very different physicochemical character, a universal approach for their isolation and characterization should be developed. This study demonstrates the systematic development of the extraction strategy that represents one of the key challenges in effective algae bioprospecting, which predefines their further industrial application. By using of Trachydiscus minutus as a model microalgae biomass, following procedures were tested and critically evaluated in order to develop the generic procedure for microalgae bioprospecting: (i) various ways of mechanical disintegration of algae cells enabling maximum extraction efficiency, (ii) the use of a wide range of extraction solvents/solvent mixtures suitable for optimal extraction yields of polar, medium-polar, and non-polar compounds, (iii) the use of consecutive extractions as a fractionation approach. Within the study, targeted screening of selected compounds representing broad range of polarities was realized by ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometric detection (UHPLC-HRMS/MS), to assess the effectiveness of undertaken isolation steps. As a result, simple and high-throughput extraction-fractionation strategy based on consecutive extraction with water-aqueous methanol-hexane/isopropanol was developed. Moreover, to demonstrate the potential of the UHPLC-HRMS/MS for the retrospective non-target screening and compounds identification, the collected mass spectra have been evaluated to characterize the pattern of extracted metabolites. Attention was focused on medium-/non-polar extracts and characterization of lipid species

  20. An ultra-high-performance liquid chromatography-tandem mass spectrometric method for the determination of hederacoside C, a drug candidate for respiratory disorder, in rat plasma.

    Science.gov (United States)

    Rehman, Shaheed Ur; Choi, Min Sun; Kim, In Sook; Kim, Seung Hyun; Yoo, Hye Hyun

    2016-09-10

    Hederacoside C is a principal bioactive pharmaceutical ingredient of Hedera helix leaf extracts. H. helix extracts have long been used in folk medicine for the treatment of respiratory disorders. Currently, hederacoside C is investigated as a promising candidate for the treatment of respiratory diseases. In this study, an accurate, sensitive, rapid, and reliable bioanalytical method was developed for the determination of hederacoside C in rat plasma using ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). For sample preparation, plasma proteins were precipitated with 0.1% acetic acid in acetonitrile. Waters UPLC BEH C18 (2.1mm I.D.×100mm, 1.7μm) column was used for chromatographic separation. A gradient elution of mobile phases consisting of 0.02% acetic acid in distilled water (solvent A) and 0.02% acetic acid in acetonitrile (solvent B) was used at a flow rate of 0.3mL/min. The multiple reaction monitoring (MRM) mode was used for mass spectrometric detection; the MRM transitions were m/z 1219.7→m/z 469.2 for hederacoside C and m/z 1108.3→m/z 221.2 for ginsenoside Rb1 (internal standard) in the negative ionization mode. A calibration curve was constructed in the range of 10-1000ng/mL. The intra- and inter-day precision and accuracy were within 5%. The developed UPLC-MS/MS method was successfully applied in a pharmacokinetic study of hederacoside C in rats. Hederacoside C was quickly but inadequately absorbed from the gastrointestinal tract of rats resulting in extremely low bioavailability and relatively slow clearance.

  1. Peptides from two sanguinovorous leeches analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometric detector

    Directory of Open Access Journals (Sweden)

    Ling Xiao

    2015-01-01

    Full Text Available Background: Hirudo nipponica Whitman and Poecilobdella manillensis Lesson fall into the family of Hirudinidae Whitman, both of them are sanguinovorous leeches and used a anticoagulant medicines in China. Their medicinal parts are the dried bodies. However, the peptides in the dried body of the two leeches have not been very clear up to now. Objective: To analyze the peptides from two sanguinovorous leeches, H. nipponica and P. manillensis. Materials and Methods: In this article it is reported that the peptides were obtained from anticoagulant active extracted parts of dried bodies of the two leeches and their molecular weights were analyzed by ultra-performance liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometry mass spectrometric detector online. Results: Three peptide components were identified from H. nipponica with their molecular weight separately 14998, 15988, and 15956, six peptide components were identified from P. manillensis with molecular weight 9590, 13642, 14998, 17631, 15988, and 16567. Two of peptides from P. manillensis have the same molecular weight 14998 and 15988 as that in H. nipponica. Conclusion: And the two peptides are the main peaks in the base peak ion chromatogram because they occupied a large ratio of total base peak area. Hence the composition of the extracted active part of the two leeches are very close, difference is in that the extract of P. manillensis has more small peptide peaks, but the extract of H. nipponica has not. Furthermore, the tryptic digestion hydrolysates of the extracted active part of each sample were analyzed and the results showed that there were four peaks which only exist in P. manillensis, but not in Hirudo nipponia. They may be the identified peak between the two leeches. This work support the viewpoint that P. manillensis can be used as a medicinal leech as H. nipponia and these peptide components of dried bodies of the two species leeches are a

  2. Simultaneous determination of major type A and B trichothecenes, zearalenone and certain modified metabolites in Finnish cereal grains with a novel liquid chromatography-tandem mass spectrometric method.

    Science.gov (United States)

    Nathanail, Alexis V; Syvähuoko, Jenna; Malachová, Alexandra; Jestoi, Marika; Varga, Elisabeth; Michlmayr, Herbert; Adam, Gerhard; Sieviläinen, Elina; Berthiller, Franz; Peltonen, Kimmo

    2015-06-01

    A reliable and sensitive liquid chromatography-tandem mass spectrometric method was developed for the simultaneous quantitative determination in cereals of the Fusarium mycotoxins HT-2 toxin, T-2 toxin, deoxynivalenol, nivalenol and zearalenone, as well as the modified metabolites 3-acetyl-deoxynivalenol, α-zearalenol, β-zearalenol, deoxynivalenol-3-glucoside, HT-2-3-glucoside, nivalenol-3-glucoside, zearalenone-14-glucoside, zearalenone-14-sulphate, zearalenone-16-glucoside, α-zearalenol-14-glucoside and β-zearalenol-14-glucoside. The 'dilute and shoot' approach was used for sample preparation after extraction with acetonitrile:water:acetic acid (79:20:1, v/v/v). Separation was carried out using reversed-phase liquid chromatography, and detection was performed using tandem mass spectrometry in the selected reaction monitoring mode. The method was in-house validated according to performance characteristics, established in Commission Regulation EC No 401/2006 and Commission Decision EC No 657/2002, prior to its application in a nationwide survey for the analysis of barley, oat and wheat samples (n = 95) harvested in Finland during 2013. Deoxynivalenol and its glucosylated form were the most abundant of the analytes, being detected in 93 and 81 % of the samples, respectively. Concentrations of deoxynivalenol were unusually high in 2013, especially in oats, with some cases exceeding the maximum legislative limits for unprocessed oats placed on the market for first-stage processing. All modified mycotoxins analysed were detected, and the natural occurrence of some of these compounds (e.g. zearalenone-16-glucoside and nivalenol-3-glucoside) in barley, oats and/or wheat was documented for the first time.

  3. Bioprospecting of microalgae: Proper extraction followed by high performance liquid chromatographic-high resolution mass spectrometric fingerprinting as key tools for successful metabolom characterization.

    Science.gov (United States)

    Stranska-Zachariasova, Milena; Kastanek, Petr; Dzuman, Zbynek; Rubert, Josep; Godula, Michal; Hajslova, Jana

    2016-03-15

    Currently, the interest in microalgae as a source of biologically active components exploitable as supplementary ingredients to food/feed or in cosmetics continues to increase. Existing research mainly aims to focus on revealing and recovering the rare, cost competitive components of the algae metabolom. Because these components could be of very different physicochemical character, a universal approach for their isolation and characterization should be developed. This study demonstrates the systematic development of the extraction strategy that represents one of the key challenges in effective algae bioprospecting, which predefines their further industrial application. By using of Trachydiscus minutus as a model microalgae biomass, following procedures were tested and critically evaluated in order to develop the generic procedure for microalgae bioprospecting: (i) various ways of mechanical disintegration of algae cells enabling maximum extraction efficiency, (ii) the use of a wide range of extraction solvents/solvent mixtures suitable for optimal extraction yields of polar, medium-polar, and non-polar compounds, (iii) the use of consecutive extractions as a fractionation approach. Within the study, targeted screening of selected compounds representing broad range of polarities was realized by ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometric detection (UHPLC-HRMS/MS), to assess the effectiveness of undertaken isolation steps. As a result, simple and high-throughput extraction-fractionation strategy based on consecutive extraction with water-aqueous methanol-hexane/isopropanol was developed. Moreover, to demonstrate the potential of the UHPLC-HRMS/MS for the retrospective non-target screening and compounds identification, the collected mass spectra have been evaluated to characterize the pattern of extracted metabolites. Attention was focused on medium-/non-polar extracts and characterization of lipid species

  4. Mass spectrometric determination of atomization energies of inorganic molecules and their correlation by empirical models of bonding

    International Nuclear Information System (INIS)

    The application of the Knudsen effusion method combined with mass spectrometry for the measurement of atomization energies of inorganic molecules is described. Recent results with emphasis on molecular metals, intermetallic molecules and metal carbides are presented. The use and limitations of various empirica models of bonding are illustrated by comparing experimental values with those calculated by the various models

  5. Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison

    NARCIS (Netherlands)

    Hintikka, L.; Kuuranne, T.; Leinonen, A.; Thevis, M.; Schanzer, W.; Halket, J.; Cowan, D.; Grosse, J.; Hemmersbach, P.; Nielen, M.W.F.; Kostiainen, R.

    2008-01-01

    Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in huma

  6. Venom landscapes: mining the complexity of spider venoms via a combined cDNA and mass spectrometric approach.

    Science.gov (United States)

    Escoubas, Pierre; Sollod, Brianna; King, Glenn F

    2006-05-01

    The complexity of Australian funnel-web spider venoms has been explored via the combined use of MALDI-TOF mass spectrometry coupled with chromatographic separation and the analysis of venom-gland cDNA libraries. The results show that these venoms are far more complex than previously realized. We show that the venoms of Australian funnel-web spiders contain many hundreds of peptides that follow a bimodal distribution, with about 75% of the peptides having a mass of 3000-5000 Da. The mass spectral data were validated by matching the experimentally observed masses with those predicted from peptide sequences derived from analysis of venom-gland cDNA libraries. We show that multiple isoforms of these peptides are found in small chromatographic windows, which suggests that the wide distribution of close molecular weights among the chromatographic fractions probably reflects a diversity of structures and physicochemical properties. The combination of all predicted and measured parameters permits the interpretation of three-dimensional 'venom landscapes' derived from LC-MALDI analysis. We propose that these venom landscapes might have predictive value for the discovery of various groups of pharmacologically distinct toxins in complex venoms.

  7. Developing a discrimination rule between breast cancer patients and controls using proteomics mass spectrometric data: A three-step approach

    NARCIS (Netherlands)

    Heidema, A.G.; Nagelkerke, N.

    2008-01-01

    To discriminate between breast cancer patients and controls, we used a three-step approach to obtain our decision rule. First, we ranked the mass/charge values using random forests, because it generates importance indices that take possible interactions into account. We observed that the top ranked

  8. Electrospray ionization quadrupole time-of-flight tandem mass spectrometric analysis of hexamethylenediamine-modified maltodextrin and dextran

    NARCIS (Netherlands)

    Sisu, E.; Bosker, W.T.E.; Norde, W.; Slaghek, T.M.; Timmermans, J.W.; Peter-Katalinić, J.; Cohen-Stuart, M.A.; Zamfir, A.D.

    2006-01-01

    A combined methodology for obtaining at the preparative scale and characterization by nanoelectrospray ionization (nanoESI) quadrupole time-of-flight (QTOF) mass spectrometry (MS) and tandem MS (MS/MS) of linear polysaccharides modified at the reducing end is presented. Two polydisperse maltodextrin

  9. Mass spectrometer introduction line: application to the analysis of impurities in uranium hexafluoride; Ligne d'introduction pour spectrometre de masse: application a l'analyse des impuretes contenues dans l'UF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Besson, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement de physico-chimie, service des isotopes stables, section de spectrometrie de masse

    1967-01-01

    The continuous mass-spectrometric analysis of impurities in UF{sub 6} is possible industrially if certain conditions imposed by the nature of the gas are respected. The gas introduction line arriving at the spectrometer's source makes it possible to fix the flow-rate, to control the inlet pressure and to selectively destroy the gas containing the impurities. The operational conditions for the line are defined and a description is given of the theoretical and experimental study of the various elements of which it is composed, i.e. the leak valve, the flow-meter, the chemical trap and the servo-mechanism making it possible to regulate and control the gas flow. The dynamic characteristics of the line's various components and the performance of the equipment in the case of the analyses considered are given. (author) [French] L'analyse en continu par spectrometrie de masse des impuretes contenus dans l'UF{sub 6} est possible industriellement moyennant certaines conditions imposees par la nature du gaz. La ligne d'introduction des gaz dans la source du spectrometre permet de regler le debit, de controler la pression d'introduction et de detruire selectivement le gaz porteur d'impuretes. Les conditions de fonctionnement de la ligne etant definies, on decrit l'etude theorique et experimentale des differents elements qui la composent, c'est-a-dire: le robinet a fuite, le debitmetre, le piege chimique et l'ensemble d'asservissement permettant la regulation et le controle du debit. On donne les caracteristiques dynamiques des differents constituants de la ligne et les performances de l'ensemble pour les analyses considerees. (auteur)

  10. Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination

    International Nuclear Information System (INIS)

    An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (2/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20 min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100 pg kg-1 for 5-300 mg of sample.

  11. TLC/HPTLC with Direct Mass Spectrometric Detection: A Review of the Progress Achieved in the Last 5 Years

    Science.gov (United States)

    Schiller, Jurgen; Fuchs, Beate; Teuber, Kristin; Nimptsch, Ariane; Nimptsch, Kathrin; Süß, Rosmarie

    Thin-layer chromatography (TLC) is a widely used, fast and inexpensive method. Even minor constituents of complex mixtures can be often characterized. Unfortunately, the unambiguous assignment of the spots to defined compounds is often difficult because common staining methods normally reveal only (at best) a substance class, not a specific compound. For instance, in the case of phospholipids, the lipid class, but not the detailed fatty acyl composition, can be determined (normal phase TLC). Nowadays mass spectrometry (MS) seems to be the most suitable method for analyte characterization due to its high sensitivity and mass accuracy. This became possible by the invention of soft ionization methods such as matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) MS and electrospray ionization (ESI) although many further desorption techniques are available nowadays. This review summarizes the so far available knowledge about direct TLC/MS couplings and gives an overview about selected compounds that could be successfully analyzed.

  12. Mass spectrometric detection of multiple extended series of neutral highly fucosylated N-acetyllactosamine oligosaccharides in human milk

    Science.gov (United States)

    Pfenninger, Anja; Chan, Shiu-Yung; Karas, Michael; Finke, Berndt; Stahl, Bernd; Costello, Catherine E.

    2008-12-01

    Complex mixtures of high-molecular weight fractions of pooled neutral human milk oligosaccharides (obtained via gel permeation chromatography) have been investigated. The subfractions were each permethylated and analyzed by high-resolution mass spectrometry, using matrix-assisted laser desorption/ionization (MALDI)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry, in order to investigate their oligosaccharide compositions. The obtained spectra reveal that human milk contains more complex neutral oligosaccharides than have been described previously; the data show that these oligosaccharides can be highly fucosylated, and that their poly-N-acetyllactosamine cores are substituted with up to 10 fucose residues on an oligosaccharide that has 7-N-acetyllactosamine units. This is the first report of the existence in human milk of this large range of highly fucosylated oligosaccharides which possess novel, potentially immunologically active structures.

  13. Rapid mass spectrometric analysis of 15N-Leu incorporation fidelity during preparation of specifically labeled NMR samples

    DEFF Research Database (Denmark)

    Truhlar, Stephanie M E; Cervantes, Carla F; Torpey, Justin W;

    2008-01-01

    analyzing the isotopic abundance of the peptides in the mass spectra using the program DEX. This analysis determined that expression with a 10-fold excess of unlabeled amino acids relative to the (15)N-amino acid prevents the scrambling of the (15)N label that is observed when equimolar amounts are used......Advances in NMR spectroscopy have enabled the study of larger proteins that typically have significant overlap in their spectra. Specific (15)N-amino acid incorporation is a powerful tool for reducing spectral overlap and attaining reliable sequential assignments. However, scrambling of the label...... during protein expression is a common problem. We describe a rapid method to evaluate the fidelity of specific (15)N-amino acid incorporation. The selectively labeled protein is proteolyzed, and the resulting peptides are analyzed using MALDI mass spectrometry. The (15)N incorporation is determined by...

  14. New approaches for the mass spectrometric determination of trace concentrations and congener group patterns of chlorinated paraffins in biota

    OpenAIRE

    Reth, Margot

    2006-01-01

    The determination of chlorinated paraffins (CPs) in the environment is important, since CPs are persistent, bioaccumulative and toxic. However, the analysis of these complex mixtures containing thousands of isomers is also a demanding task. CP analysis and especially the quantification of CPs are far from being well established. In this work, new methodologies were developed for the determination of CPs in biota by low-resolution mass spectrometry (LRMS). The use of expensiv...

  15. Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection

    OpenAIRE

    Zygler, Agata; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

    2011-01-01

    An analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages, dairy and fish products). After extraction with a buffer...

  16. Development and application of mass-spectrometric methods for the quantification and characterization of organic compounds in ice cores

    OpenAIRE

    Müller-Tautges, Christina

    2014-01-01

    Eisbohrkerne stellen wertvolle Klimaarchive dar, da sie atmosphärisches Aerosol konservieren. Die Analyse chemischer Verbindungen als Bestandteil atmosphärischer Aerosole in Eisbohrkernen liefert wichtige Informationen über Umweltbedingungen und Klima der Vergangenheit. Zur Untersuchung der α-Dicarbonyle Glyoxal und Methylglyoxal in Eis- und Schneeproben wurde eine neue, sensitive Methode entwickelt, die die Stir Bar Sorptive Extraction (SBSE) mit der Hochleistungsflüssigchromatographie-Masse...

  17. Mass spectrometric and bioinformatics approaches to characterizing of cyclic non-ribosomal peptides and ribosomally encoded peptide antibiotic

    OpenAIRE

    Liu, Wei-Ting

    2009-01-01

    Natural products are a crucial component in drug discovery because of their considerable pharmaceutical properties. Cyclic non-ribosomally peptides are one category of natural products featured by containing non-standard amino acids and lactam or lactone structures, thus increasing the complexity of the resulting tandem mass spectrometry data. Cyclosporin, microcystins and nodularins all are well-known examples and have notable pharmacologically importance. In this current work, by collaborat...

  18. Development of a Novel System for Mass Spectrometric Analysis of Cancer-Associated Fucosylation in Plasma α1-Acid Glycoprotein

    Directory of Open Access Journals (Sweden)

    Takayuki Asao

    2013-01-01

    Full Text Available Human plasma α1-acid glycoprotein (AGP from cancer patients and healthy volunteers was purified by sequential application of ion-exchange columns, and N-linked glycans enzymatically released from AGP were labeled and applied to a mass spectrometer. Additionally, a novel software system for use in combination with a mass spectrometer to determine N-linked glycans in AGP was developed. A database with 607 glycans including 453 different glycan structures that were theoretically predicted to be present in AGP was prepared for designing the software called AGPAS. This AGPAS was applied to determine relative abundance of each glycan in the AGP molecules based on mass spectra. It was found that the relative abundance of fucosylated glycans in tri- and tetra-antennary structures (FUCAGP was significantly higher in cancer patients as compared with the healthy group (P<0.001. Furthermore, extremely elevated levels of FUCAGP were found specifically in patients with a poor prognosis but not in patients with a good prognosis. In conclusion, the present software system allowed rapid determination of the primary structures of AGP glycans. The fucosylated glycans as novel tumor markers have clinical relevance in the diagnosis and assessment of cancer progression as well as patient prognosis.

  19. A VUV photoionization mass spectrometric study on the OH-initiated photooxidation of isoprene with synchrotron radiation

    Institute of Scientific and Technical Information of China (English)

    Gang Pan; Jun Chen; Fuyi Liu; Xiaobin Shan; Liusi Sheng; Changjin Hu; Mingqiang Huang; Zhenya Wang; Yue Cheng; Zhi Liu; Xuejun Gu; Weixiong Zhao; Weijun Zhang

    2012-01-01

    The gas-phase organic compounds resulting from OH-initiated photooxidation of isoprene have been investigated on-line by VUV photoionization mass spectrometry based on synchrotron radiation for the first time.The photoionization efficiency curves of the corresponding gaseous products as well as the chosen standards have been deduced by gating the interested peaks in the photoionization mass spectra while scanning the photon energy simultaneously,which permits the identification of the pivotal gaseous products of the photooxidation of isoprene,such as formaldehyde (10.84 eV),formic acid (11.38 eV),acetone (9.68 eV),glyoxal (9.84 eV),acetic acid (10.75 eV),methacrolein (9.91 eV),and methyl vinyl ketone (9.66 eV).Proposed reaction mechanisms leading to the formation of these key products were discussed,which were completely consistent with the previous works of different groups.The capability of synchrotron radiation photoionization mass spectrometry to directly identify the chemical composition of the gaseous products in a simulation chamber has been demonstrated,and its potential application in related studies of atmospheric oxidation of ambient volatile organic compounds is anticipated.

  20. Solid-phase microextraction /gas-chromatographic /mass-spectrometric analysis of p-dichlorobenzene and naphthalene in honey

    OpenAIRE

    Petros A. Tarantilis

    2008-01-01

    Abstract Protection of honey combs from wax moth Galleria mellonella involves the use of physical, biological or chemical control methods. Chemical control may results of residues in the extracted honey. The presence of residues of p-dichlorobenzene and naphthalene in honey were investigated by means of solid-phase microextraction (SPME) coupled to gas-chromatography and mass-spectrometry (GC/MS). The method was linear between 5 ig/kg and 200 ig/kg of honey for p-dichlorobenzene an...

  1. Authenticity assessment of beef origin by principal component analysis of matrix-assisted laser desorption/ionization mass spectrometric data.

    Science.gov (United States)

    Zaima, Nobuhiro; Goto-Inoue, Naoko; Hayasaka, Takahiro; Enomoto, Hirofumi; Setou, Mitsutoshi

    2011-06-01

    It has become necessary to assess the authenticity of beef origin because of concerns regarding human health hazards. In this study, we used a metabolomic approach involving matrix-assisted laser desorption/ionization imaging mass spectrometry to assess the authenticity of beef origin. Highly accurate data were obtained for samples of extracted lipids from beef of different origin; the samples were grouped according to their origin. The analysis of extracted lipids in this study ended within 10 min, suggesting this approach can be used as a simple authenticity assessment before a definitive identification by isotope analysis.

  2. Mass Spectrometric Studies of the Effect of pH on the Accumulation of Intermediates in Denitrification by Paracoccus denitrificans

    OpenAIRE

    Thomsen, Jens K.; Geest, Torben; Cox, Raymond P.

    1994-01-01

    We have used a quadrupole mass spectrometer with a gas-permeable membrane inlet for continuous measurements of the production of N2O and N2 from nitrate or nitrite by cell suspensions of Paracoccus denitrificans. The use of nitrate and nitrite labeled with 15N was shown to simplify the interpretation of the results when these gases were measured. This approach was used to study the effect of pH on the production of denitrification intermediates from nitrate and nitrite under anoxic conditions...

  3. Quantitative Mass spectrometric Analysis of Ropivacaine and Bupivacaine in Authentic, Pharmaceutical and Spiked Human Plasma without Chromatographic Separation

    Directory of Open Access Journals (Sweden)

    Nahla N. Salama

    2009-01-01

    Full Text Available The present study employs time of flight mass spectrometry for quantitative analysis of the local anesthetic drugs ropivacaine and bupivacaine in authentic, pharmaceutical and spiked human plasma as well as in the presence of their impurities 2,6-dimethylaniline and alkaline degradation product. The method is based on time of flight electron spray ionization mass spectrometry technique without preliminary chromatographic separation and makes use of bupivacaine as internal standard for ropivacaine, which is used as internal standard for bupivacaine. A linear relationship between drug concentrations and the peak intensity ratio of ions of the analyzed substances is established. The method is linear from 23.8 to 2380.0 ng mL-1 for both drugs. The correlation coefficient was ≥0.996 in authentic and spiked human plasma. The average percentage recoveries in the ranges of 95.39%–102.75% was obtained. The method is accurate (% RE < 5% and reproducible with intra- and inter-assay precision (RSD% < 8.0%. The quantification limit is 23.8 ng mL-1 for both drugs. The method is not only highly sensitive and selective, but also simple and effective for determination or identification of both drugs in authentic and biological fluids. The method can be applied in purity testing, quality control and stability monitoring for the studied drugs.

  4. Improvement of the Digestibility of Sulfated Hyaluronans by Bovine Testicular Hyaluronidase: A UV Spectroscopic and Mass Spectrometric Study

    Directory of Open Access Journals (Sweden)

    Katharina Lemmnitzer

    2014-01-01

    Full Text Available Glycosaminoglycans (GAGs such as hyaluronan (HA and chondroitin sulfate (CS are important, natural polysaccharides which occur in biological (connective tissues and have various biotechnological and medical applications. Additionally, there is increasing evidence that chemically (oversulfated GAGs possess promising properties and are useful as implant coatings. Unfortunately, a detailed characterization of these GAGs is challenging: although mass spectrometry (MS is one of the most powerful tools to elucidate the structures of (polysaccharides, MS is not applicable to high mass polysaccharides, but characteristic oligosaccharides are needed. These oligosaccharides are normally generated by enzymatic digestion. However, chemically modified (particularly sulfated GAGs are extremely refractive to enzymatic digestion. This study focuses on the investigation of the digestibility of GAGs with different degrees of sulfation by bovine testicular hyaluronidase (BTH. It will be shown by using an adapted spectrophotometric assay that all investigated GAGs can be basically digested if the reaction conditions are carefully adjusted. However, the oligosaccharide yield correlates reciprocally with the number of sulfate residues per polymer repeating unit. Finally, matrix-laser desorption and ionization (MALDI MS will be used to study the released oligosaccharides and their sulfation patterns.

  5. A mass spectrometric study of the acid-catalysed d-fructose dehydration in the gas phase.

    Science.gov (United States)

    Pepi, Federico; Ricci, Andreina; Garzoli, Stefania; Troiani, Anna; Salvitti, Chiara; Di Rienzo, Brunella; Giacomello, Pierluigi

    2015-09-01

    5-hydroxymethylfuraldehyde (5-HMF) and simpler compounds, such as levulinic acid (LA) and glyceraldehyde, are platform molecules produced by the thermal acid-catalyzed dehydration of carbohydrates coming from biomass. Understanding sugar degradation pathways on a molecular level is necessary to increase selectivity, reduce degradation by-products yields and optimize catalytic strategies, fundamental knowledge for the development of a sustainable renewable industry. In this work gaseous protonated d-fructose ions, generated in the ESI source of a triple quadrupole mass spectrometer, were allowed to undergo Collisionally Activated Decomposition (CAD) into the quadrupole collision cell. The ionic intermediates and products derived from protonated d-fructose dehydration were structurally characterized by their fragmentation patterns and the relative water-loss dehydration energies measured by energy-resolved CAD mass spectra. The data were compared with those obtained from protonated d-glucose decomposition in the same experimental conditions. In the gas phase, d-fructose dehydration leads to the formation of a mixed population of isomeric [C6H6O3]H(+) ions, whose structures do not correspond exclusively to 5-hydroxymethyl-2-furaldehyde protonated at the more basic aldehydic group. PMID:26122965

  6. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    Science.gov (United States)

    Lee, Chang Young; Fan, Yi; Rubakhin, Stanislav S.; Yoon, Sook; Sweedler, Jonathan V.

    2016-06-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns.

  7. A multiresidue liquid chromatographic/tandem mass spectrometric method for the detection and quantitation of 15 nonsteroidal anti-inflammatory drugs (NSAIDs) in bovine meat and milk.

    Science.gov (United States)

    van Pamel, Els; Daeseleire, Els

    2015-06-01

    This study concerns a validated liquid chromatographic/tandem mass spectrometric (LC-MS/MS) multiresidue method for the simultaneous detection, identification, and quantitation of 15 nonsteroidal anti-inflammatory drugs (NSAIDs) in bovine meat and milk. The NSAIDs considered are carprofen, diclofenac, flufenamic acid, flunixin (5-hydroxyflunixin as marker metabolite in milk), ketoprofen, mefenamic acid, meloxicam, 4-methylaminoantipyrine (marker metabolite of metamizole in meat and milk), naproxen, niflumic acid, phenylbutazone (and metabolite oxyphenbutazone), ramifenazone, salicylic acid, and tolfenamic acid. These compounds were chosen as representatives of different chemical subclasses of NSAIDs. Flunixin-d3, diclofenac-d4, 4-aminoantipyrine-d3, and phenylbutazone-d10 were used as internal standards. Performance characteristics were validated according to the Commission Decision 2002/657/EC (Off J Eur Communities, L221: 8-36). Recovery percentages varied between 81 and 114% for bovine meat and between 79 and 118% for milk. Repeatability percentages were within the range of 1-12% for meat and between 1 and 17% for milk, whereas the intralaboratory reproducibility varied between 3 and 19% for meat and between 3 and 23% for milk. The decision limit and the detection capability for bovine meat were within the range of 0.5-579 μg kg(-1)and 0.6-642 μg kg(-1), respectively. Those for milk were within the range of 0.12-55 μg kg(-1) and 0.14-61 μg kg(-1), respectively. The methods developed were successfully applied for proficiency test samples and routine samples analyzed in the laboratory. The methodology concerns fast, user-friendly, and sensitive methods, which can be easily extended for other compounds and matrices. In general, such multiresidue methods contribute to the reduction of human exposure to these veterinary drug residues by consumption of contaminated bovine-derived products such as meat and milk.

  8. Oral and topical pharmacokinetic studies of a novel TRPV1 antagonist, PAC-14028 in rats and minipigs using liquid chromatography/tandem mass spectrometric method.

    Science.gov (United States)

    Park, Yang-Hui; Joo, Kyung-Mi; Woo, Byoung-Young; Son, Eui Dong; Byun, Sang Yo; Shin, Hong-Ju; Lee, Ki-Wha; Park, Young-Ho; Lim, Kyung-Min

    2012-03-01

    PAC-14028 ((E)-N-((R)-1-(3,5-difluoro-4-methanesulfonylamino-phenyl)-ethyl)-3-(2-propyl-6-trifluoromethyl-pyridine-3-yl)-acrylamide) is a novel and potent transient receptor potential vanilloid type I (TRPV1) antagonist. We developed and validated a rapid, sensitive and selective liquid chromatography/tandem mass spectrometric method for determination of PAC-14028 in rat and minipig plasma. After protein precipitation PAC-14028 and internal standard (methylated analog, PAC-14026) were separated on a Symmetry C(18) column (4.6 mm × 75 mm, 3.5 μm) with an isocratic mobile phase, acetonitrile: water (8:2, v/v) containing 0.2% formic acid and monitored by electrospray positive ionization with multiple reaction monitoring mode (PAC-14028, 492→156; IS, 506→156, m/z). The calibration curve was linear over the range of 1.0-500 ng/ml (r(2)>0.999) and lower limit of quantitation (LLOQ) was 1 ng/ml. The precision and accuracy were within ± 15% and the stability was acceptable during bench-top, auto-sampler, 3 freeze-thaw cycles and 4-week storage in a freezer at -80°C. This method was successfully applied to the intravenous, oral and topical pharmacokinetic studies of PAC-14028 in rats and minipigs, which showed comparable pharmacokinetic parameters (T1/2, 2.1h and 3.8h; F%, 52.7% and 64.2% for rats and minipigs, respectively). Percutaneous absorption of PAC-14028 was negligible after topical application (F% 0.2-1.7%). PMID:22169466

  9. Single-walled carbon nanotubes coated fibers for solid-phase microextraction and gas chromatography-mass spectrometric determination of pesticides in Tea samples.

    Science.gov (United States)

    Wu, Fang; Lu, Wanping; Chen, Jinghua; Liu, Wei; Zhang, Lan

    2010-08-15

    Using a single-walled carbon nanotubes (SWCNTs) as stationary phase of solid-phase microextraction (SPME) fibers, a simple, low cost and environmentally friendly method for extraction of 13 pesticides in Tea samples has been developed following gas chromatography-mass spectrometric determination. Potential factors affecting the extraction efficiency were investigated and optimized, including extraction and desorption time, extraction temperature, stirring rate, solution pH and ionic strength. Under optimized conditions, the linearity of the developed method was in the range of 0.125-25 ng/mL with correlation coefficients greater than 0.9928 and the limits of detections (LODs) were 0.027-0.23 ng/mL (S/N=3). Meanwhile, the relative standard deviations (RSDs) for five successive measurements with single fiber, fiber-to-fiber, day-to-day were 2.3-13.0, 8.2-14.6 and 4.1-12.5%, respectively, indicating good reproducibility of the proposed method. The fiber had high extraction efficiency for studied pesticides in comparison with commercial poly(dimethylsiloxane) (PDMS) and polyacrylate (PA) fibers and could be used for more than 70 times without decrease of efficiency. The developed method was successfully applied for the analysis of real samples including green Tea, oolong Tea, white Tea, and flower Tea, and the recoveries of the pesticides spiked in these samples ranged from 75.1 to 118.4%. Chlorfenapyr and lambda-cyhalothrin were found in the Tea samples bought randomly from local market. The results demonstrated that the developed SWCNTs-SPME method was a simple, efficient pretreatment and enrichment procedure for pesticides in complex matrices. PMID:20678665

  10. A high-performance liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric method for determination of risperidone and 9-hydroxyrisperidone in human plasma.

    Science.gov (United States)

    Moody, David E; Laycock, John D; Huang, Wei; Foltz, Rodger L

    2004-09-01

    Risperidone, a benzisoxazole derivative, is an antipsychotic agent used for the treatment of schizophrenia. We developed a liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric (LC-APCI-MS-MS) method with improved sensitivity, selectivity, and dynamic range for determination of risperidone and 9-hydroxyrisperidone in human plasma. A structural analogue of risperidone, RO68808 (5 ng/mL), is added as the internal standard to 1 mL of human plasma. Plasma is made basic, extracted with pentane/methylene chloride (3:1), the organic phase evaporated to dryness, and the residue is reconstituted in water with 0.1% formic acid/acetonitrile (20:1). For LC-MS-MS analysis, a Metachem Inertsel HPLC column (2.1 x 150 mm, 5-microm particle size) is connected to a Finnigan TSQ7000 tandem MS via the Finnigan API interface. Both electrospray (ESI) and APCI produced predominantly MH(+) ions for the two analytes and the internal standard. Ions detected by selected reaction monitoring correspond to the following transitions: m/z 411 to 191 for risperidone, m/z 427 to 207 for 9-hydroxyrisperidone, and m/z 421 to 201 for the internal standard. APCI provided a larger dynamic range (0.1 to 25 ng/mL) and better precision and accuracy than ESI. Intrarun accuracy and precision determined at 0.1, 0.25, 2.5, and 15 ng/mL were within 12% of target with %CVs not exceeding 10.9%. Interrun accuracy and precision determined at the same concentrations were within 9.6% of target with %CVs not exceeding 6.7%. Analytes were stable in plasma after 24 h at room temperature, 2 freeze-thaw cycles, and 490 days at -20 degrees C. PMID:15516302

  11. Mass spectrometric U-series dating of Huanglong Cave in Hubei Province, Central China: evidence for early presence of modern humans in Eastern Asia.

    Science.gov (United States)

    Shen, Guanjun; Wu, Xianzhu; Wang, Qian; Tu, Hua; Feng, Yue-xing; Zhao, Jian-xin

    2013-08-01

    Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ∼50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia. PMID:23870460

  12. Determination of total lead in 400 lipsticks on the U.S. market using a validated microwave-assisted digestion, inductively coupled plasma-mass spectrometric method.

    Science.gov (United States)

    Hepp, Nancy M

    2012-01-01

    In 2009, the U.S. Food and Drug Administration (FDA) published lead (Pb) content results from a small survey of 20 tube lipsticks with red shades using a validated inductively coupled plasma-mass spectrometric (ICP-MS) method developed by FDA chemists. The study was prompted by a media report suggesting that potential exposure to lead from lipsticks under conditions of ordinary use might be harmful. The FDA has since investigated the lead content of tube lipsticks by conducting an expanded survey that included a variety of shades and manufacturers, at varying prices. The purposes of the expanded survey were to ascertain the levels of lead in lipsticks sold on the U.S. market, to identify any categories of lipstick with elevated levels of lead, and to compare the results to those from the initial small survey. Four hundred lipsticks available on the U.S. market in the spring of 2010 were tested for total lead content using the FDA's validated method. The analyses were performed by a private laboratory contracted by the FDA. The maximum lead level found was 7.19 mg Pb/kg. Thirteen of the 400 lipsticks were found to contain levels greater than 3.06 mg Pb/kg, the highest amount found in the initial survey. The average lead concentration found in the expanded survey was 1.11 mg Pb/kg, which was very close to the average of 1.07 mg Pb/kg found in the initial survey. Some statistically significant associations between lead level and parent company were found. The contract requirements, testing procedures, and findings from the expanded survey are described here. PMID:23193690

  13. Ambient ionization mass spectrometric analysis of human surgical specimens to distinguish renal cell carcinoma from healthy renal tissue.

    Science.gov (United States)

    Alfaro, Clint M; Jarmusch, Alan K; Pirro, Valentina; Kerian, Kevin S; Masterson, Timothy A; Cheng, Liang; Cooks, R Graham

    2016-08-01

    Touch spray-mass spectrometry (TS-MS) is an ambient ionization technique (ionization of unprocessed samples in the open air) that may find intraoperative applications in quickly identifying the disease state of cancerous tissues and in defining surgical margins. In this study, TS-MS was performed on fresh kidney tissue (∼1-5 cm(3)), within 1 h of resection, from 21 human subjects afflicted by renal cell carcinoma (RCC). The preliminary diagnostic value of TS-MS data taken from freshly resected tissue was evaluated. Principal component analysis (PCA) of the negative ion mode (m/z 700-1000) data provided the separation between RCC (16 samples) and healthy renal tissue (13 samples). Linear discriminant analysis (LDA) on the PCA-compressed data estimated sensitivity (true positive rate) and specificity (true negative rate) of 98 and 95 %, respectively, based on histopathological evaluation. The results indicate that TS-MS might provide rapid diagnostic information in spite of the complexity of unprocessed kidney tissue and the presence of interferences such as urine and blood. Desorption electrospray ionization-MS imaging (DESI-MSI) in the negative ionization mode was performed on the tissue specimens after TS-MS analysis as a reference method. The DESI imaging experiments provided phospholipid profiles (m/z 700-1000) that also separated RCC and healthy tissue in the PCA space, with PCA-LDA sensitivity and specificity of 100 and 89 %, respectively. The TS and DESI loading plots indicated that different ions contributed most to the separation of RCC from healthy renal tissue (m/z 794 [PC 34:1 + Cl](-) and 844 [PC 38:4 + Cl](-) for TS vs. m/z 788 [PS 36:1 - H](-) and 810 [PS 38:4 - H](-) for DESI), while m/z 885 ([PI 38:4 - H](-)) was important in both TS and DESI. The prospect, remaining hurdles, and future work required for translating TS-MS into a method of intraoperative tissue diagnosis are discussed. Graphical abstract Touch spray-mass spectrometry used for

  14. Carbon-enhanced inductively coupled plasma mass spectrometric detection of arsenic and selenium and its application to arsenic speciation

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Sturup, Stefan

    1994-01-01

    Addition of carbon as methanol or ammonium carbonate to the aqueous analyte solutions in combination with increased plasma power input enhanced the inductively coupled plasma mass spectrometry (ICP-MS) signal intensities of arsenic and selenium. In the presence of the optimum 3% v/v methanol...... concentration the signal intensities achieved were about 4500-5000 counts s-1 per ng ml-1 of arsenic and about 700-1100 counts s-1 per ng ml-1 of selenium (Se-82), corresponding to enhancement factors of 3.5-4.5 compared with aqueous solution for the two elements. Differences in sensitivity (calculated...... on the basis of analyte atom) were observed between the individual arsenic species and between the selenium species in aqueous as well as in carbon-added solutions. The presence of 3% v/v methanol in the analyte solutions doubled the level of the background signal for arsenic and selenium, but its fluctuation...

  15. Mass spectrometric study of thermodynamic properties of gaseous lead tellurates. Estimation of formation enthalpies of gaseous lead polonates

    Science.gov (United States)

    Shugurov, S. M.; Panin, A. I.; Lopatin, S. I.; Emelyanova, K. A.

    2016-10-01

    Gaseous reactions involving lead oxides, tellurium oxide and lead tellurates were studied by the Knudsen effusion mass spectrometry. Equilibrium constants and reaction enthalpies were evaluated. Structures, molecular parameters and thermodynamic functions of gaseous PbTeO3 and Pb2TeO4 were calculated by quantum chemistry methods. The formation enthalpies ΔfH0 (298.15) = -294 ± 13 for gaseous PbTeO3 and ΔfH0 (298.15) = -499 ± 12 for gaseous Pb2TeO4 were obtained. On the base of these results the formation enthalpies of gaseous PbPoO3 and Pb2PoO4 were estimated as -249 ± 34 and -478 ± 38, respectively.

  16. Extraction estimation and gas chromatographic mass spectrometric analysis of the non polar fraction of the pistia stratiotes

    International Nuclear Information System (INIS)

    The non-polar compounds of the Pistia stratiotes were extracted using n-hexane as solvent. The extraction yields were determined both for the cold and hot extraction procedure as 8.50 +- 0.05% and 12.00 +- 0.05%, respectively. The extract was analyzed and separated into its components using GC equipped with FID and GC mass in separate experiments. The most important compounds identified in n-hexane extract of leaves of P. stratiotes are long chain compound of the nitrogenous nature and oxygenated compounds of mixed functional groups. The antibacterial activity of this fraction was investigated against eight pathogenic bacteria using disc diffusion method. Larger zones of inhibition were observed for Bacillus subtilis, Pseudomonas aeruginosa and Agrobacterium tumefaciens as compared to Klebsiella pneumoniaee and Staphylococcus aureus where the activity was relatively less. No activity was observed against Escherichia coli, Salmonella typhi and Bacillus atrophaeus. (author)

  17. Determination of plasticizers included in balloon by solid phase microextraction and gas chromatography with mass spectrometric detection.

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.M.; Kim, J.H.; Ryu, J.Ch.; Kim, Y.M.; Lee, K.B. [Korea Institute of Science and Technology, Seoul (Korea)

    2001-02-01

    Solid-phase microextraction (SPME) with 85 {mu}m polyacrylate fiber, coupled to gas chromatography-mass spectrometry was used to analyze the plasticizers contained in balloon samples. The balloons were identified to be made of polyisoprene by IR spectroscopy. The plasticizers extracted from the balloon samples soaked in acetone-added water solvent for an hour were quantified by external standard method using nine kinds of plasticizers. The quantification method was validated for standard plasticizers in the range of 0.25-25 {mu}g/g. The detection limits were 0.11-0.38 {mu}g/g for different plasticizers. The RSDs for the reproducibility of this quantitation method were 3.7-14.2%. A few of balloons included risky level of plasticizer concerned as an endocrine disrupter, and it is necessary to regulate these products. (author). 10 refs., 3 tabs., 4 figs.

  18. Automated on-line liquid-liquid extraction system for temporal mass spectrometric analysis of dynamic samples.

    Science.gov (United States)

    Hsieh, Kai-Ta; Liu, Pei-Han; Urban, Pawel L

    2015-09-24

    Most real samples cannot directly be infused to mass spectrometers because they could contaminate delicate parts of ion source and guides, or cause ion suppression. Conventional sample preparation procedures limit temporal resolution of analysis. We have developed an automated liquid-liquid extraction system that enables unsupervised repetitive treatment of dynamic samples and instantaneous analysis by mass spectrometry (MS). It incorporates inexpensive open-source microcontroller boards (Arduino and Netduino) to guide the extraction and analysis process. Duration of every extraction cycle is 17 min. The system enables monitoring of dynamic processes over many hours. The extracts are automatically transferred to the ion source incorporating a Venturi pump. Operation of the device has been characterized (repeatability, RSD = 15%, n = 20; concentration range for ibuprofen, 0.053-2.000 mM; LOD for ibuprofen, ∼0.005 mM; including extraction and detection). To exemplify its usefulness in real-world applications, we implemented this device in chemical profiling of pharmaceutical formulation dissolution process. Temporal dissolution profiles of commercial ibuprofen and acetaminophen tablets were recorded during 10 h. The extraction-MS datasets were fitted with exponential functions to characterize the rates of release of the main and auxiliary ingredients (e.g. ibuprofen, k = 0.43 ± 0.01 h(-1)). The electronic control unit of this system interacts with the operator via touch screen, internet, voice, and short text messages sent to the mobile phone, which is helpful when launching long-term (e.g. overnight) measurements. Due to these interactive features, the platform brings the concept of the Internet-of-Things (IoT) to the chemistry laboratory environment. PMID:26423626

  19. Probing organic ligands and their binding schemes on nanocrystals by mass spectrometric and FT-IR spectroscopic imaging

    Science.gov (United States)

    Son, Jin Gyeong; Choi, Eunjin; Piao, Yuanzhe; Han, Sang Woo; Lee, Tae Geol

    2016-02-01

    We report an analysis method to identify conjugated ligands and their binding states on semiconductor nanocrystals based on their molecular information. Surface science techniques, such as time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and FT-IR spectroscopy, are adopted based on the micro-aggregated sampling method. Typical trioctylphosphine oxide-based synthesis methods of CdSe/ZnS quantum dots (QDs) have been criticized because of the peculiar effects of impurities on the synthesis processes. Because the ToF-SIMS technique provides molecular composition evidence on the existence of certain ligands, we were able to clearly identify n-octylphosphonic acid (OPA) as a surface ligand on CdSe/ZnS QDs. Furthermore, the complementary use of the ToF-SIMS technique with the FT-IR technique could reveal the OPA ligands' binding state as bidentate complexes.We report an analysis method to identify conjugated ligands and their binding states on semiconductor nanocrystals based on their molecular information. Surface science techniques, such as time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and FT-IR spectroscopy, are adopted based on the micro-aggregated sampling method. Typical trioctylphosphine oxide-based synthesis methods of CdSe/ZnS quantum dots (QDs) have been criticized because of the peculiar effects of impurities on the synthesis processes. Because the ToF-SIMS technique provides molecular composition evidence on the existence of certain ligands, we were able to clearly identify n-octylphosphonic acid (OPA) as a surface ligand on CdSe/ZnS QDs. Furthermore, the complementary use of the ToF-SIMS technique with the FT-IR technique could reveal the OPA ligands' binding state as bidentate complexes. Electronic supplementary information (ESI) available: Additional data (Fig. S1-S5). See DOI: 10.1039/c5nr07592k

  20. Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane.

    Science.gov (United States)

    Rotavera, Brandon; Zádor, Judit; Welz, Oliver; Sheps, Leonid; Scheer, Adam M; Savee, John D; Akbar Ali, Mohamad; Lee, Taek Soon; Simmons, Blake A; Osborn, David L; Violi, Angela; Taatjes, Craig A

    2014-11-01

    Product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). Interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperature over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals. Quantum-chemical and master-equation calculations of the unimolecular decomposition of the primary alkyl radical reveal that isomerization to the tertiary alkyl radical is the most favorable pathway, and is favored over O2-addition at 650 K under the conditions herein. The isomerization pathway to tertiary alkyl radicals therefore contributes an additional mechanism to 2,2,5,5-tetramethyltetrahydrofuran formation; (3) carbonyl species (acetone, propanal, and methylpropanal) consistent with β-scission of QOOH radicals were formed in significant yield, indicating unimolecular QOOH decomposition into carbonyl + alkene + OH.

  1. Theory and Application of Mass Spectrometric Kinetic Method%质谱动力学方法原理及应用

    Institute of Scientific and Technical Information of China (English)

    李明; 李红梅; 熊行创; 江游; 黄泽建; 方向

    2012-01-01

    The mass spectrometric kinetic method based on the competitive dissociations of mass-selected cluster ions has been increasingly applied to thermochemical determination mainly due to its simplicity, speediness and sensitivity. Because the kinetic method employs tandem mass spectrometry, the compounds of interest need not be available in pure form. The kinetic method has been used to estimate gas-phase acidity and basicity and proton affinity, electron affinity, ionization energy, gas-phase basicities of multiply-charged biomole-cules, metal ion affinities, heterolytic bond dissociation energies, chiral recognition and quantification. In this paper the theory of kinetic method is introduced in detail and its applications are enumerated.%质谱动力学方法(Kinetic Method,简称KM法)是一种基于经质量选择的簇离子竞争解离反应速率的不同对热力学数据进行测定的方法,由于采用串联质谱技术,分析样品无需纯化,具有简便、快速、灵敏等优点.目前该方法已应用于气相酸碱度和质子亲合势的测定、电子亲和能的测定、电离能的测定、多电荷生物分子气相碱度的测定、金属离子与生物分子亲和力的测定、异裂离解能的测定、离子结构的检测及对手性化合物对映体过量的测定等.本工作在介绍质谱动力学方法原理的同时,列举了其应用实例,详细地对质谱动力学方法进行了综合述评.

  2. Mass spectrometric analysis and mutagenesis predict involvement of multiple cysteines in redox regulation of the skeletal muscle ryanodine receptor ion channel complex

    Directory of Open Access Journals (Sweden)

    Evgeniy V Petrotchenko

    2011-01-01

    Full Text Available Evgeniy V Petrotchenko1,2,4, Naohiro Yamaguchi1,3,4, Daniel A Pasek1, Christoph H Borchers1,2, Gerhard Meissner11Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA; 2University of Victoria, Genome BC Proteomics Centre, Victoria, British Columbia, Canada; 3Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA 4Contributed equally to the workAbstract: The tetrameric skeletal muscle ryanodine receptor ion channel complex (RyR1 contains a large number of free cysteines that are potential targets for redox-active molecules. Here, we report the mass spectrometric analysis of free thiols in RyR1 using the lipophilic, thiol-specific probe monobromobimane (MBB. In the presence of reduced glutathione, MBB labeled 14 cysteines per RyR1 subunit in tryptic peptides in five of five experiments. Forty-six additional MBB-labeled cysteines per RyR1 subunit were detected with lower frequency in tryptic peptides, bringing the total number of MBB-labeled cysteines to 60 per RyR1 subunit. A combination of fluorescence detection and mass spectrometry of RyR1, labeled in the presence of reduced and oxidized glutathione, identified two redox-sensitive cysteines (C1040 and C1303. Regulation of RyR activity by reduced and oxidized glutathione was investigated in skeletal muscle mutant RyR1s in which 18 cysteines were substituted with serine or alanine, using a [3H]ryanodine ligand binding assay. Three single-site RyR1 mutants (C1781S, C2436S, and C2606S and two multisite mutants with five and seven substituted cysteines exhibited a reduced redox response compared with wild-type RyR1. The results suggest that multiple cysteines determine the redox state and activity of RyR1.Keywords: mass spectrometry, mutagenesis, ryanodine receptor, redox modification of cysteines

  3. Mass spectrometric analysis of 7-sulfoxymethyl-12-methylbenz[a]anthracene and related electrophilic polycyclic aromatic hydrocarbon metabolites.

    Science.gov (United States)

    Lehner, Andreas F; Horn, Jamie; Flesher, James W

    2004-11-01

    The Meso-region theory of polycyclic aromatic hydrocarbon (PAH) carcinogenesis predicts that the development of pronounced carcinogenicity depends on the introduction of a good leaving group on alkyl side-chains attached to the exceptionally reactive meso-anthracenic or L-region positions of PAHs. Thus, the first step in carcinogenesis by methylated PAHs such as 7,12-dimethylbenz[a]anthracene (DMBA) would be the hydroxylation of the L-region methyl groups, particularly the 7-methyl group. The second would be the formation of a metabolite, e.g. a sulfate ester, which is expected to be a good leaving group capable of generating a highly reactive benzylic carbocation. 7-Hydroxymethyl-12-methylbenz[a]anthracene (7-HMBA) is a metabolite of DMBA, and sulfation of 7-HMBA to a 7-sulfoxymethyl metabolite (7-SMBA) is a known Phase II metabolic process designed to facilitate excretion, but actually enabling more destructive side-reactions. These side-reactions occur with generation of an electrophilic 7-methylene carbonium ion, and/or by in vivo halide exchange to provide neutral side-products more capable of entering cells, especially those of DMBA target tissues. Electrospray ionization mass spectrometry (MS) enabled us to visualize 7-SMBA as an intact m/z 351 conjugate anion by negative mode, and as a released m/z 255 carbonium ion by positive mode. Upon prolonged refrigeration, 7-SMBA accumulated an m/z 383 photooxide, which appeared capable of re-evolving the starting material as visualized by tandem quadrupole MS, or MS/MS. The 7-SMBA carbonium ion provided interpretable fragments when studied by fragment ion MS/MS, including those representing the loss of up to several protons. Subtle differences in this property were encountered upon perturbing 7-SMBA, either by warming it at 37 degrees C for 2 h or by substituting the initial sulfoxy group with an iodo group. Side-reactions accounting for such proton losses are proposed, and are of interest whether they occur in the

  4. Insulin sensitivity is reflected by characteristic metabolic fingerprints--a Fourier transform mass spectrometric non-targeted metabolomics approach.

    Directory of Open Access Journals (Sweden)

    Marianna Lucio

    Full Text Available BACKGROUND: A decline in body insulin sensitivity in apparently healthy individuals indicates a high risk to develop type 2 diabetes. Investigating the metabolic fingerprints of individuals with different whole body insulin sensitivity according to the formula of Matsuda, et al. (ISI(Matsuda by a non-targeted metabolomics approach we aimed a to figure out an unsuspicious and altered metabolic pattern, b to estimate a threshold related to these changes based on the ISI, and c to identify the metabolic pathways responsible for the discrimination of the two patterns. METHODOLOGY AND PRINCIPAL FINDINGS: By applying infusion ion cyclotron resonance Fourier transform mass spectrometry, we analyzed plasma of 46 non-diabetic subjects exhibiting high to low insulin sensitivities. The orthogonal partial least square model revealed a cluster of 28 individuals with alterations in their metabolic fingerprints associated with a decline in insulin sensitivity. This group could be separated from 18 subjects with an unsuspicious metabolite pattern. The orthogonal signal correction score scatter plot suggests a threshold of an ISI(Matsuda of 15 for the discrimination of these two groups. Of note, a potential subgroup represented by eight individuals (ISI(Matsuda value between 8.5 and 15 was identified in different models. This subgroup may indicate a metabolic transition state, since it is already located within the cluster of individuals with declined insulin sensitivity but the metabolic fingerprints still show some similarities with unaffected individuals (ISI >15. Moreover, the highest number of metabolite intensity differences between unsuspicious and altered metabolic fingerprints was detected in lipid metabolic pathways (arachidonic acid metabolism, metabolism of essential fatty acids and biosynthesis of unsaturated fatty acids, steroid hormone biosyntheses and bile acid metabolism, based on data evaluation using the metabolic annotation interface Mass

  5. Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection.

    Science.gov (United States)

    Zygler, Agata; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

    2011-06-01

    An analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages, dairy and fish products). After extraction with a buffer composed of formic acid and N,N-diisopropylethylamine at pH 4.5 in ultrasonic bath, extracts were cleaned up using Strata-X 33 μm Polymeric SPE column. The analytes were separated in gradient elution mode on C(18) column and detected by mass spectrometer working with an electrospray source in negative ion mode. To confirm that analytical method is suitable for its intended use, several validation parameters, such as linearity, limits of detection and quantification, trueness and repeatibilty were evaluated. Calibration curves were linear within a studied range of concentrations (r(2) ≥ 0.999) for six investigated sweeteners (CYC, ASP, ALI, DUL, NHDC, NEO). Three compounds (ACS-K, SAC, SCL) gave non-linear response in the investigated concentration range. The method detection limits (corresponding to signal-to-noise (S/N) ratio of 3) were below 0.25 μg mL(-1) (μg g(-1)), whereas the method quantitation limits (corresponding to S/N ratio of 10) were below 2.5 μg mL(-1) (μg g(-1)). The recoveries at the tested concentrations (50%, 100% and 125% of maximum usable dose) for all sweeteners were in the range of 84.2 ÷ 106.7%, with relative standard deviations sweeteners in drinks, yoghurts and fish products. The procedure described here is simple, accurate and precise and is suitable for routine quality control analysis of foodstuffs. PMID:21465096

  6. Mass spectrometric analysis of 7-sulfoxymethyl-12-methylbenz[a]anthracene and related electrophilic polycyclic aromatic hydrocarbon metabolites.

    Science.gov (United States)

    Lehner, Andreas F; Horn, Jamie; Flesher, James W

    2004-11-01

    The Meso-region theory of polycyclic aromatic hydrocarbon (PAH) carcinogenesis predicts that the development of pronounced carcinogenicity depends on the introduction of a good leaving group on alkyl side-chains attached to the exceptionally reactive meso-anthracenic or L-region positions of PAHs. Thus, the first step in carcinogenesis by methylated PAHs such as 7,12-dimethylbenz[a]anthracene (DMBA) would be the hydroxylation of the L-region methyl groups, particularly the 7-methyl group. The second would be the formation of a metabolite, e.g. a sulfate ester, which is expected to be a good leaving group capable of generating a highly reactive benzylic carbocation. 7-Hydroxymethyl-12-methylbenz[a]anthracene (7-HMBA) is a metabolite of DMBA, and sulfation of 7-HMBA to a 7-sulfoxymethyl metabolite (7-SMBA) is a known Phase II metabolic process designed to facilitate excretion, but actually enabling more destructive side-reactions. These side-reactions occur with generation of an electrophilic 7-methylene carbonium ion, and/or by in vivo halide exchange to provide neutral side-products more capable of entering cells, especially those of DMBA target tissues. Electrospray ionization mass spectrometry (MS) enabled us to visualize 7-SMBA as an intact m/z 351 conjugate anion by negative mode, and as a released m/z 255 carbonium ion by positive mode. Upon prolonged refrigeration, 7-SMBA accumulated an m/z 383 photooxide, which appeared capable of re-evolving the starting material as visualized by tandem quadrupole MS, or MS/MS. The 7-SMBA carbonium ion provided interpretable fragments when studied by fragment ion MS/MS, including those representing the loss of up to several protons. Subtle differences in this property were encountered upon perturbing 7-SMBA, either by warming it at 37 degrees C for 2 h or by substituting the initial sulfoxy group with an iodo group. Side-reactions accounting for such proton losses are proposed, and are of interest whether they occur in the

  7. Isotope ratio mass spectrometric method for the on-line determination of oxygen-18 in organic matter.

    Science.gov (United States)

    Koziet, J

    1997-01-01

    A method for the on-line determination of oxygen-18, at a naturally occurring level, in organic material is presented. After pyrolysis of the samples to form carbon monoxide, which is performed at 1300 degrees C in a vitreous carbon tube, the pyrolysis products are transported by a stream of helium gas. Using an open split, a small part of the effluent is transferred to the ion source of an isotope ratio mass spectrometer. The ratio is obtained from a measurement of the ion current intensities at m/z 30 and 28 (12C18O and 12C16O). The method was tested with the secondary water standard GISP (Greenland Ice Sheet Precipitation) and the carbonate standard NBS 19. The values obtained were -24.8/1000 and 27.3/1000 vs. VSMOW (Vienna Standard Mean Ocean Water) (LAEA reference values are -24.8/1000 and 28.7/1000 vs. VSMOW). The potential of the method was demonstrated by measuring the 18O content of samples of beet and cane sucrose and also samples of vanillin extracted from vanilla pods or of synthetic origin. PMID:9008872

  8. Standard methods for chemical, mass spectrometric, and spectrochemical analysis of, and physical tests on, beryllium oxide powder

    International Nuclear Information System (INIS)

    Methods are described for the determination of C, Fe, N, Cl-, Li, S, thirty trace elements, and the amount of BeO in BeO powder. Methods are included for certain physical properties of the oxide powders. C is determined by the combustion-thermal conductivity method. A colorimetric method using orthophenanthroline is used for the determination of Fe, and N is determined by a micro Kjeldahl method. Chlorine is determined nephlometrically using AgNO3, and Li is determined by atomic absorption spectrophotometry. A complete burning spectrochemical method and a spark-source mass spectrographic method were used to analyze for the thirty trace elements. The density of the BeO powders was measured by a toluene displacement method, and a tap-pak volumetric method was used for the determination of the pour and tap densities. Two different methods described for the particle-size composition determination are Coulter Counter method and sieve analysis method. Methods for determination of bulk density, real density, porosity, and pore size of the solid oxides are described. A nitrogen absorption method is described for the determination of surface area

  9. Advanced analytical mass spectrometric techniques and bioassays to characterize untreated and ozonated oil sands process-affected water.

    Science.gov (United States)

    Sun, Nian; Chelme-Ayala, Pamela; Klamerth, Nikolaus; McPhedran, Kerry N; Islam, Md Shahinoor; Perez-Estrada, Leonidas; Drzewicz, Przemysław; Blunt, Brian J; Reichert, Megan; Hagen, Mariel; Tierney, Keith B; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2014-10-01

    Oil sands process-affected water (OSPW) is a toxic and poorly biodegradable mixture of sand, silt, heavy metals, and organics. In this study, qualitative and quantitative comparisons of naphthenic acids (NAs) were done using ultraperformance liquid chromatography time-of-flight mass spectrometry (UPLC TOF-MS), Fourier transform ion cyclotron resonance (FT-ICR) MS, and ion mobility spectrometry (IMS). The unique combination of these analyses allowed for the determination and correlation of NAs, oxidized NAs, and heteroatom (sulfur or nitrogen) NAs. Despite its lower resolution, UPLC-TOF MS was shown to offer a comparable level of reliability and precision as the high resolution FT-ICR MS. Additionally, the impacts of ozonation (35 mg/L utilized ozone dose) and subsequent NAs degradation on OSPW toxicity were assessed via a collection of organisms and toxicity end points using Vibrio fischeri (nonspecific), specific fish macrophage antimicrobial responses, and fish olfactory responses. Fish macrophages exposed to ozonated OSPW for 1 week showed higher production of reactive oxygen and nitrogen intermediates; however, after 12 weeks the responses were reduced significantly. Fish olfactory tests suggested that OSPW interfered with their perception of odorants. Current results indicate that the quantification of NAs species, using novel analytical methods, can be combined with various toxicity methods to assess the efficiency of OSPW treatment processes. PMID:25211339

  10. Inductively coupled plasma mass-spectrometric determination of platinum in excretion products of client-owned pet dogs.

    Science.gov (United States)

    Janssens, T; Brouwers, E E M; de Vos, J P; de Vries, N; Schellens, J H M; Beijnen, J H

    2015-06-01

    Residues of antineoplastic drugs in canine excretion products may represent exposure risks to veterinary personnel, owners of pet dogs and other animal care-takers. The aim of this study was to measure the extent and duration of platinum (Pt) excretion in pet dogs treated with carboplatin. Samples were collected before and up to 21 days after administration of carboplatin. We used validated, ultra-sensitive, inductively coupled plasma-mass spectrometry assays to measure Pt in canine urine, faeces, saliva, sebum and cerumen. Results showed that urine is the major route of elimination of Pt in dogs. In addition, excretion occurs via faeces and saliva, with the highest amounts eliminated during the first 5 days. The amount of excreted Pt decreased over time but was still quantifiable at 21 days after administration of carboplatin. In conclusion, increased Pt levels were found in all measured excretion products up to 21 days after administration of carboplatin to pet dogs, with urine as the main route of excretion. These findings may be used to further adapt current veterinary guidelines on safe handling of antineoplastic drugs and treated animals. PMID:23714139

  11. Production, Purification, and Characterization of 15N-Labeled DNA Repair Proteins as Internal Standards for Mass Spectrometric Measurements

    Science.gov (United States)

    Jaruga, Pawel; Nelson, Bryant C.; Lowenthal, Mark S.; Jemth, Ann-Sofie; Loseva, Olga; Coskun, Erdem; Helleday, Thomas

    2016-01-01

    Oxidatively induced DNA damage is caused in living organisms by a variety of damaging agents, resulting in the formation of a multiplicity of lesions, which are mutagenic and cytotoxic. Unless repaired by DNA repair mechanisms before DNA replication, DNA lesions can lead to genomic instability, which is one of the hallmarks of cancer. Oxidatively induced DNA damage is mainly repaired by base excision repair pathway with the involvement of a plethora of proteins. Cancer tissues develop greater DNA repair capacity than normal tissues by overexpressing DNA repair proteins. Increased DNA repair in tumors that removes DNA lesions generated by therapeutic agents before they became toxic is a major mechanism in the development of therapy resistance. Evidence suggests that DNA repair capacity may be a predictive biomarker of patient response. Thus, knowledge of DNA–protein expressions in disease-free and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. Our laboratory has developed methodologies that use mass spectrometry with isotope dilution for the measurement of expression of DNA repair proteins in human tissues and cultured cells. For this purpose, full-length 15N-labeled analogs of a number of human DNA repair proteins have been produced and purified to be used as internal standards for positive identification and accurate quantification. This chapter describes in detail the protocols of this work. The use of 15N-labeled proteins as internal standards for the measurement of several DNA repair proteins in vivo is also presented. PMID:26791985

  12. Gas chromatographic-mass spectrometric fragmentation study of phytoestrogens as their trimethylsilyl derivatives: Identification in soy milk and wastewater samples

    Science.gov (United States)

    Ferrer, I.; Barber, L.B.; Thurman, E.M.

    2009-01-01

    An analytical method for the identification of eight plant phytoestrogens (biochanin A, coumestrol, daidzein, equol, formononetin, glycitein, genistein and prunetin) in soy products and wastewater samples was developed using gas chromatography coupled with ion trap mass spectrometry (GC/MS-MS). The phytoestrogens were derivatized as their trimethylsilyl ethers with trimethylchlorosilane (TMCS) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The phytoestrogens were isolated from all samples with liquid-liquid extraction using ethyl acetate. Daidzein-d4 and genistein-d4 labeled standards were used as internal standards before extraction and derivatization. The fragmentation patterns of the phytoestrogens were investigated by isolating and fragmenting the precursor ions in the ion-trap and a typical fragmentation involved the loss of a methyl and a carbonyl group. Two characteristic fragment ions for each analyte were chosen for identification and confirmation. The developed methodology was applied to the identification and confirmation of phytoestrogens in soy milk, in wastewater effluent from a soy-milk processing plant, and in wastewater (influent and effluent) from a treatment plant. Detected concentrations of genistein ranged from 50,000 ??g/L and 2000 ??g/L in soy milk and in wastewater from a soy-plant, respectively, to 20 ??g/L and <1 ??g/L for influent and effluent from a wastewater treatment plant, respectively. ?? 2009 Elsevier B.V.

  13. A robust and rapid liquid chromatography tandem mass spectrometric method for the quantitative analysis of 5-azacytidine.

    Science.gov (United States)

    Anders, Nicole M; Wanjiku, Teresia M; He, Ping; Azad, Nilofer S; Rudek, Michelle A

    2016-03-01

    The DNA methyltransferase inhibitor 5-azacytidine is being evaluated clinically as an oral formulation to treat various solid tumors. A sensitive, reliable method was developed to quantitate 5-azacytidine using LC-MS/MS to perform detailed pharmacokinetic studies. The drug of interest was extracted from plasma using Oasis MCX ion exchange solid-phase extraction 96-well plates. Chromatographic separation was achieved with a YMC J'sphere M80 C18 column and isocratic elution with a methanol-water-formic acid (15:85:0.1, v/v/v) mobile phase over a 7 min total analytical run time. An AB Sciex 5500 triple quadrupole mass spectrometer operated in positive electrospray ionization mode was used for the detection of 5-azacytidine. The assay range was 5-500 ng/mL and proved to be accurate (97.8-109.1%) and precise (CV ≤ 9.8%). Tetrahydrouridine was used to stabilize 5-azacytidine in blood/plasma samples. With the addition of tetrahydrouridine, long-term frozen plasma stability for 5-azacytidine at -70°C has been determined for at least 323 days. The method was applied for the measurement of total plasma concentrations of 5-azacytidine in a cancer patient receiving a 300 mg oral daily dose. PMID:26174363

  14. A robust and rapid liquid chromatography tandem mass spectrometric method for the quantitative analysis of 5-azacytidine

    Science.gov (United States)

    Anders, Nicole M.; Wanjiku, Teresia M.; He, Ping; Azad, Nilofer S.; Rudek, Michelle A.

    2015-01-01

    The DNA methyltransferase inhibitor 5-azacytidine is being evaluated clinically as an oral formulation to treat various solid tumors. A sensitive, reliable method was developed to quantitate 5-azacytidine using LC-MS/MS to perform detailed pharmacokinetic studies. The drug of interest was extracted from plasma using Oasis MCX ion exchange solid-phase extraction 96-well plates. Chromatographic separation was achieved with an YMC J'sphere M80 C18 column and isocratic elution with a methanol-water-formic acid (15:85:0.1, v/v/v) mobile phase over a 7 minute total analytical run time. An AB Sciex 5500 triple quadrupole mass spectrometer operated in positive electrospray ionization mode was used for the detection of 5-azacytidine. The assay range was 5 to 500 ng/mL and proved to be accurate (97.8-109.1%) and precise (%CV ≤9.8%). Tetrahydrouridine was used to stabilize 5-azacytidine in blood/plasma samples. With the addition of tetrahydrouridine, long-term frozen plasma stability for 5-azacytidine at -70°C has been determined for at least 323 days. The method was applied for the measurement of total plasma concentrations of 5-azacytidine in a cancer patient receiving a 300 mg oral daily dose. PMID:26174363

  15. Antioxidant activity and gas chromatographic-mass spectrometric analysis of extracts of the marine algae, caulerpa peltata and padina gymnospora

    Directory of Open Access Journals (Sweden)

    Kavitha Murugan

    2014-01-01

    Full Text Available The results of our previous investigations on extracts of selected marine algae showed that Caulerpa peltata and Padina gymnospora had more promising antiproliferative and antioxidant activities than Gelidiella acerosa and Sargassum wightii. Based on these results, the more active chloroform extract of C. peltata and ethyl acetate extract of P. gymnospora were further analyzed for their constituents by using gas chromatography in tandem with mass spectrometry. The GC-MS analysis (GC % peak area given in parentheses showed that fucosterol (12.45% and L-(+-ascorbic acid 2,6-dihexadecanoate (8.13% were the major compounds present in P. gymnospora ethyl acetate extract. On the other hand, C. peltata chloroform extract had 1-heptacosanol (10.52%, hexacosanol acetate (9.28%, tetradecyl ester of chloroacetic acid (7.22%, Z,Z-6,28-heptatriactontadien-2-one (6.77% and 10,13-dimethyl-methyl ester of tetradecanoic acid (5.34% as major compounds. Also described in the report are the beta-carotene bleaching inhibitory and total reducing activities of the chloroform and ethyl acetate extracts of C. peltata and P. gymnospora, respectively, relative to the other three extracts (aqueous, methanol, chloroform or ethyl acetate of the two algae.

  16. Shotgun Proteomics of Tomato Fruits: Evaluation, Optimization and Validation of Sample Preparation Methods and Mass Spectrometric Parameters.

    Science.gov (United States)

    Kilambi, Himabindu V; Manda, Kalyani; Sanivarapu, Hemalatha; Maurya, Vineet K; Sharma, Rameshwar; Sreelakshmi, Yellamaraju

    2016-01-01

    An optimized protocol was developed for shotgun proteomics of tomato fruit, which is a recalcitrant tissue due to a high percentage of sugars and secondary metabolites. A number of protein extraction and fractionation techniques were examined for optimal protein extraction from tomato fruits followed by peptide separation on nanoLCMS. Of all evaluated extraction agents, buffer saturated phenol was the most efficient. In-gel digestion [SDS-PAGE followed by separation on LCMS (GeLCMS)] of phenol-extracted sample yielded a maximal number of proteins. For in-solution digested samples, fractionation by strong anion exchange chromatography (SAX) also gave similar high proteome coverage. For shotgun proteomic profiling, optimization of mass spectrometry parameters such as automatic gain control targets (5E+05 for MS, 1E+04 for MS/MS); ion injection times (500 ms for MS, 100 ms for MS/MS); resolution of 30,000; signal threshold of 500; top N-value of 20 and fragmentation by collision-induced dissociation yielded the highest number of proteins. Validation of the above protocol in two tomato cultivars demonstrated its reproducibility, consistency, and robustness with a CV of < 10%. The protocol facilitated the detection of five-fold higher number of proteins compared to published reports in tomato fruits. The protocol outlined would be useful for high-throughput proteome analysis from tomato fruits and can be applied to other recalcitrant tissues. PMID:27446192

  17. Quantitative secondary ion mass spectrometric analysis of secondary ion polarity in GaN films implanted with oxygen

    Science.gov (United States)

    Hashiguchi, Minako; Sakaguchi, Isao; Adachi, Yutaka; Ohashi, Naoki

    2016-10-01

    Quantitative analyses of N and O ions in GaN thin films implanted with oxygen ions (16O+) were conducted by secondary ion mass spectrometry (SIMS). Positive (CsM+) and negative secondary ions extracted by Cs+ primary ion bombardment were analyzed for oxygen quantitative analysis. The oxygen depth profiles were obtained using two types of primary ion beams: a Gaussian-type beam and a broad spot beam. The oxygen peak concentrations in GaN samples were from 3.2 × 1019 to 7.0 × 1021 atoms/cm3. The depth profiles show equivalent depth resolutions in the two analyses. The intensity of negative oxygen ions was approximately two orders of magnitude higher than that of positive ions. In contrast, the O/N intensity ratio measured using CsM+ molecular ions was close to the calculated atomic density ratio, indicating that the SIMS depth profiling using CsM+ ions is much more effective for the measurements of O and N ions in heavy O-implanted GaN than that using negative ions.

  18. Effects of Glucose Feeding on Respiration and Photosynthesis in Photoautotrophic Dianthus caryophyllus Cells: Mass Spectrometric Determination of Gas Exchange.

    Science.gov (United States)

    Avelange, M H; Sarrey, F; Rébillé, F

    1990-11-01

    When glucose (20 millimolar) was added to photoautotrophic cell suspension cultures of Dianthus caryophyllus, there was during the first 10 hours an accumulation of carbohydrates and phosphorylated compounds. These biochemical changes were accompanied by a progressive decrease of net photosynthesis and a twofold increase of the dark respiratory rate. The rise of respiration was associated with a rise of fumarase and cytochrome c oxidase activities, two mitochondrial markers. Gas exchange of illuminated cells were performed with a mass spectrometry technique and clearly established that during the first hours of glucose feeding, the decrease of net photosynthesis was essentially due to an increase of respiration in light, whereas the photosynthetic processes (gross O(2) evolution and gross CO(2) fixation) were almost not affected. However, after 24 hours of experiment, O(2) evolution and CO(2) fixation started to decline in turn. While ribulose-1,5-bisphosphate carboxylase activity was little affected during the first 48 hours of the experiment, the maximal light-induced phosphoribulokinase activity dramatically decreased with time and represented after 48 hours only 30% of its initial activity. It is postulated that the decrease in phosphoribulokinase activity was at least partially responsible for the decrease of CO(2) fixation and the metabolic events involved in this regulation are discussed.

  19. Determination of free amino compounds in betalainic fruits and vegetables by gas chromatography with flame ionization and mass spectrometric detection.

    Science.gov (United States)

    Kugler, Florian; Graneis, Stephan; Schreiter, Pat P-Y; Stintzing, Florian C; Carle, Reinhold

    2006-06-14

    Amino acids and amines are the precursors of betalains. Therefore, the profiles of free amino compounds in juices obtained from cactus pears [Opuntia ficus-indica (L.) Mill. cv. Bianca, cv. Gialla, and cv. Rossa], pitaya fruits [Selenicereus megalanthus (K. Schumann ex Vaupel) Moran, Hylocereus polyrhizus (Weber) Britton & Rose, and Hylocereus undatus (Haworth) Britton & Rose], and in extracts from differently colored Swiss chard [Beta vulgaris L. ssp. cicla (L.) Alef. cv. Bright Lights] petioles and red and yellow beets (B. vulgaris L. ssp. vulgaris var. conditiva Alef. cv. Burpee's Golden) were investigated for the first time. Amino compounds were derivatized with propyl chloroformate. While gas chromatography (GC) with mass spectrometry was used for peak assignment, GC flame ionization detection was applied for quantification of individual compounds. Whereas proline was the major free amino compound of cactus pear and pitaya fruit juices, glutamine dominated in Swiss chard stems and beets, respectively. Interestingly, extremely high concentrations of dopamine were detected in Swiss chard stems and beets. Furthermore, the cleavage of betaxanthins caused by derivatization in alkaline reaction solutions is demonstrated for the first time. Amino acids and amines thus released might increase the actual free amino compound contents of the respective sample. To evaluate the contribution of betaxanthin cleavage to total amino acid and amine concentration, isolated betaxanthins were derivatized according to the "EZ:faast" method prior to quantification of the respective amino compounds released. On a molar basis, betaxanthin contribution to overall amino compound contents was always below 6.4%. PMID:16756361

  20. Significant sensitivity improvements by matrix optimization: a MALDI-TOF mass spectrometric study of lipids from hen egg yolk.

    Science.gov (United States)

    Teuber, Kristin; Schiller, Jürgen; Fuchs, Beate; Karas, Michael; Jaskolla, Thorsten W

    2010-06-01

    Due to its sensitivity, the tolerance of impurities and the simplicity of performance, matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is increasingly used to analyze lipids from biological sources. Although its detailed role is not understood so far, the applied matrix has a pronounced effect on the achievable spectrum quality and particularly how sensitive the individual lipid classes are detectable. Different matrix compounds were recently established in the lipid field including 2,5-dihydroxybenzoic acid (DHB), 9-aminoacridine (9-AA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), and 2-(2-aminoethylamino)-5-nitropyridine (AAN). It is the aim of this paper to compare the properties of these matrices with the newly synthesized matrix, alpha-cyano-2,4-difluorocinnamic acid (Di-FCCA). An organic extract from hen egg yolk was used as a simple and easily available test system. It will be shown that Di-FCCA is the matrix of choice to detect lipids in the positive-ion mode due to an achievable sensitivity gain of more than one order of magnitude compared to alternative matrices. In contrast, Di-FCCA is not suitable for negative-ion detection of phospholipids. Here, 9-AA is unequivocally the matrix of choice. PMID:20420816

  1. In-situ Mass Spectrometric Determination of Molecular Structural Evolution at the Solid Electrolyte Interphase in Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zihua; Zhou, Yufan; Yan, Pengfei; Vemuri, Venkata Rama Ses; Xu, Wu; Zhao, Rui; Wang, Xuelin; Thevuthasan, Suntharampillai; Baer, Donald R.; Wang, Chong M.

    2015-08-19

    Dynamic molecular evolution at solid/liquid electrolyte interface is always a mystery for a rechargeable battery due to the challenge to directly probe/observe the solid/liquid interface under reaction conditions, which in essence appears to be similarly true for all the fields involving solid/liquid phases, such as electrocatalysis, electrodeposition, biofuel conversion, biofilm, and biomineralization, We use in-situ liquid secondary ion mass spectroscopy (SIMS) for the first time to directly observe the molecular structural evolution at the solid electrode/liquid electrolyte interface for a lithium (Li)-ion battery under dynamic operating conditions. We have discovered that the deposition of Li metal on copper electrode leads to the condensation of solvent molecules around the electrode. Chemically, this layer of solvent condensate tends to deplete the salt anion and with low concentration of Li+ ions, which essentially leads to the formation of a lean electrolyte layer adjacent to the electrode and therefore contributes to the overpotential of the cell. This unprecedented molecular level dynamic observation at the solid electrode/liquid electrolyte interface provides vital chemical information that is needed for designing of better battery chemistry for enhanced performance, and ultimately opens new avenues for using liquid SIMS to probe molecular evolution at solid/liquid interface in general.

  2. Matrix-assisted laser desorption/ionization mass spectrometric analysis of aliphatic biodegradable photoluminescent polymers using new ionic liquid matrices.

    Science.gov (United States)

    Serrano, Carlos A; Zhang, Yi; Yang, Jian; Schug, Kevin A

    2011-05-15

    In this study, two novel ionic liquid matrices (ILMs), N,N-diisopropylethylammonium 3-oxocoumarate and N,N-diisopropylethylammonium dihydroxymonooxoacetophenoate, were tested for the structural elucidation of recently developed aliphatic biodegradable polymers by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The polymers, formed by a condensation reaction of three components, citric acid, octane diol, and an amino acid, are fluorescent, but the exact mechanism behind their luminescent properties has not been fully elucidated. In the original studies, which introduced the polymer class (J. Yang et al., Proc. Natl. Acad. Sci. USA 2009, 106, 10086-10091), a hyper-conjugated cyclic structure was proposed as the source for the photoluminescent behavior. With the use of the two new ILMs, we present evidence that supports the presence of the proposed cyclization product. In addition, the new ILMs, when compared with a previously established ILM, N,N-diisopropylethylammonium α-cyano-3-hydroxycinnimate, provided similar signal intensities and maintained similar spectral profiles. This research also established that the new ILMs provided good spot-to-spot reproducibility and high ionization efficiency compared with corresponding crystalline matrix preparations. Many polymer features revealed through the use of the ILMs could not be observed with crystalline matrices. Ultimately, the new ILMs highlighted the composition of the synthetic polymers, as well as the loss of water that was expected for the formation of the proposed cyclic structure on the polymer backbone.

  3. Investigation of the climatic extremes influence on the humane adaptive capacity by mass spectrometric analysis of exhaled breath condensate

    Science.gov (United States)

    Ryabokon, Anna; Larina, Irina; Kononikhin, Alexey; Starodubtceva, Nataliia; Popov, Igor; Nikolaev, Eugene; Varfolomeev, Sergey

    Global climate change, which causes abnormal fluctuations in temperature and rainfall, has adverse effects on human health. Particularly people suffer with cardiovascular and respiratory system disease. Our research was concentrated on the changes in the regulation and adaptation systems of human organism related to hyperthermia and polluted air influence. Healthy individuals with the age from 22 to 45 years were isolated during 30 days in the ground based experimental facility located at Institute of medico-biological problems RAS (Moscow, Russia). In the ground based facility artificially climatic conditions of August, 2010 in Moscow were created. Exhaled breath condensate was collected before and after isolation by R-Tube collector, freeze dried, treated by trypsin and analyzed by nanoflow LC-MS/MS with a 7-Tesla LTQ-FT Ultra mass spectrometer (Thermo Electron, Bremen, Germany). Database search was performed using Mascot Server 2.2 software (Matrix Science, London, UK). Investigation of exhaled breath condensate (EBC) collected from participants of the 30 days isolation with hyper thermic and polluted air climate conditions was performed. After isolation reduction of the protein number was observed. Loss endothelial C receptor precursor - the main physiological anticoagulant - correlate with the clinical data of physicians to increase the propensity to thrombosis. Also COP9 signalosome protein, positive regulator of ubiquitin was identified in all EBC samples before isolation and was not detected for more than a half of donors after isolation. This phenomena may be due to violation of ubiquitin protection system of the cells from harmful proteins. During isolation the air was cleared from microdisperse particles.

  4. Accelerated tryptic digestion for the analysis of biopharmaceutical monoclonal antibodies in plasma by liquid chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Lesur, Antoine; Varesio, Emmanuel; Hopfgartner, Gérard

    2010-01-01

    Accelerated tryptic digestion of a therapeutic protein including microwave irradiation and thermal transfer by convection at 60 degrees C and 37 degrees C was investigated. An analytical setup was devised to follow the protein digestion rate using 1D gel electrophoresis and liquid chromatography coupled a triple quadrupole linear ion trap mass spectrometer. The formation kinetic of its tryptic peptides was monitored in the selected monitoring mode (LC-SRM/MS). Different digestion end points (e.g. 2, 5, 10, 15, 30 and 60min) as well as an overnight digestion were tested using a therapeutic human monoclonal antibody (mAb) with the goal of its LC-SRM/MS quantification in human plasma. The peptides from the human mAb were generated at different rates and were classified into three categories: (1) the fast forming peptides, (2) the slow forming peptides and (3) the peptides degrading over time. For many monitored peptides, a heating temperature of 37 degrees C with a 750rpm mixing applied for at least 30min provided equivalent results to microwave-assisted digestion and generally allowed the achievement of an equivalent peptide concentration as an overnight digestion carried out at 37 degrees C. The disappearance of the protein of the heavy and light chains can be monitored by 1D gel electrophoresis but was found not to be representative of the final tryptic peptide concentrations. For quantitative purposes a stable isotope labeled version ((13)C(4), (15)N(1)) of the therapeutic protein was used. The labeled protein as internal standard was found to be very efficient to compensate for incomplete digestion or losses during sample preparation. PMID:19939394

  5. Quantification of Lysine Acetylation and Succinylation Stoichiometry in Proteins Using Mass Spectrometric Data-Independent Acquisitions (SWATH)

    Science.gov (United States)

    Meyer, Jesse G.; D'Souza, Alexandria K.; Sorensen, Dylan J.; Rardin, Matthew J.; Wolfe, Alan J.; Gibson, Bradford W.; Schilling, Birgit

    2016-09-01

    Post-translational modification of lysine residues by NƐ-acylation is an important regulator of protein function. Many large-scale protein acylation studies have assessed relative changes of lysine acylation sites after antibody enrichment using mass spectrometry-based proteomics. Although relative acylation fold-changes are important, this does not reveal site occupancy, or stoichiometry, of individual modification sites, which is critical to understand functional consequences. Recently, methods for determining lysine acetylation stoichiometry have been proposed based on ratiometric analysis of endogenous levels to those introduced after quantitative per-acetylation of proteins using stable isotope-labeled acetic anhydride. However, in our hands, we find that these methods can overestimate acetylation stoichiometries because of signal interferences when endogenous levels of acylation are very low, which is especially problematic when using MS1 scans for quantification. In this study, we sought to improve the accuracy of determining acylation stoichiometry using data-independent acquisition (DIA). Specifically, we use SWATH acquisition to comprehensively collect both precursor and fragment ion intensity data. The use of fragment ions for stoichiometry quantification not only reduces interferences but also allows for determination of site-level stoichiometry from peptides with multiple lysine residues. We also demonstrate the novel extension of this method to measurements of succinylation stoichiometry using deuterium-labeled succinic anhydride. Proof of principle SWATH acquisition studies were first performed using bovine serum albumin for both acetylation and succinylation occupancy measurements, followed by the analysis of more complex samples of E. coli cell lysates. Although overall site occupancy was low (<1%), some proteins contained lysines with relatively high acetylation occupancy.

  6. Extraction chromatographic methods in the sample preparation sequence for thermal ionization mass spectrometric analysis of plutonium isotopes.

    Science.gov (United States)

    Grate, Jay W; O'Hara, Matthew J; Farawila, Anne F; Douglas, Matthew; Haney, Morgan M; Petersen, Steven L; Maiti, Tapas C; Aardahl, Christopher L

    2011-12-01

    A sample preparation sequence for actinide isotopic analysis by thermal ionization mass spectrometry (TIMS) is described that includes column-based extraction chromatography as the first separation step, followed by anion-exchange column separations. The sequence is designed to include a wet ashing step after the extraction chromatography to prevent any leached extractant or oxalic acid eluent reagents from interfering with subsequent separations, source preparation, or TIMS ionization. TEVA resin and DGA resin materials, containing extractants that consist only of C, N, O, and H atoms, were investigated for isolation of plutonium. Radiotracer level studies confirmed expected high yields from column-based separation procedures. Femtogram-level studies were carried out with TIMS detection, using multiple monoisotopic spikes applied sequentially throughout the separation sequence. Pu recoveries were 87% and 86% for TEVA and DGA resin separations, respectively. The Pu recoveries from 400 μL anion-exchange column separation sequences were 89% and 93% for trial sequences incorporating TEVA and DGA resin. Thus, a prior extraction chromatography step in the sequence did not interfere with the subsequent anion-exchange separation when a simple wet ash step was carried out in between these column separations. The average measurement efficiency for Pu, encompassing the chemical separation recoveries and the TIMS ionization efficiency, was 2.73% ± 0.77% (2σ) for the DGA resin trials and 2.67% ± 0.54% for the TEVA resin trials, compared to 3.41% and 2.37% (average 2.89%) for two control trials. These compare with an average measurement efficiency of 2.78% ± 1.70%, n = 33 from process benchmark analyses using Pu spikes processed through a sequence of oxalate precipitation, wet ash, iron hydroxide precipitation, and anion-exchange column separations. We conclude that extraction chromatography can be a viable separation procedure as part of a multistep sequence for TIMS

  7. Detection of drugs in lifted cyanoacrylate-developed latent fingermarks using two laser desorption/ionisation mass spectrometric methods.

    Science.gov (United States)

    Sundar, Latha; Rowell, Frederick

    2014-02-01

    This paper describes a method for lifting cyanoacrylate (CNA)-developed latent fingermarks from a glass surface and the detection of five drugs in lifted marks from fingers that had been in contact with the drugs, using Surface Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (SALDI-TOF-MS) or Matrix Assisted Laser Desorption Ionisation TOF-MS (MALDI-TOF-MS). Two drugs of abuse (cocaine and methadone) and three therapeutic drugs (aspirin, paracetamol and caffeine) were used as contact residues. Latent fingermarks spiked with the drugs were subjected to CNA fuming followed by dusting with ARRO SupraNano™ MS black magnetic powder (SALDI-TOF-MS) or 2,5-dihydroxybenzoic acid (DHB) (MALDI-TOF-MS). The dusted mark was then exposed to solvent vapour before lifting with a commercial fingerprint lifting tape following established procedures. The presence of the drugs was then confirmed by direct analysis on the tape without further processing using SALDI- or MALDI-TOF-MS. The black magnetic fingerprint powder provided visual enhancement of the CNA-fingermark while no visual enhancement was observed for marks dusted with DHB powder. Similar [M + H](+) peaks for all the drug analytes were observed for both methods along with some sodium and potassium adducts for SALDI-MS and some major fragment ions but the SALDI signals were generally more intense. Simple exposure to acetone vapour of the CNA-developed marks enabled their effective transfer onto the tape which was crucial for subsequent MS detection of the analytes.

  8. SIFamide peptides in clawed lobsters and freshwater crayfish (Crustacea, Decapoda, Astacidea): a combined molecular, mass spectrometric and electrophysiological investigation.

    Science.gov (United States)

    Dickinson, Patsy S; Stemmler, Elizabeth A; Cashman, Christopher R; Brennan, Henry R; Dennison, Bobbi; Huber, Kristen E; Peguero, Braulio; Rabacal, Whitney; Goiney, Christopher C; Smith, Christine M; Towle, David W; Christie, Andrew E

    2008-04-01

    Recently, we identified the peptide VYRKPPFNGSIFamide (Val(1)-SIFamide) in the stomatogastric nervous system (STNS) of the American lobster Homarus americanus using matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS). Given that H. americanus is the only species thus far shown to possess this peptide, and that a second SIFamide isoform, Gly(1)-SIFamide, is broadly conserved in other decapods, including another astacidean, the crayfish Procambarus clarkii, we became interested both in confirming our identification of Val(1)-SIFamide via molecular methods and in determining the extent to which this isoform is conserved within other members of the infraorder Astacidea. Here, we present the identification and characterization of an H. americanus prepro-SIFamide cDNA that encodes the Val(1) isoform. Moreover, we demonstrate via MALDI-FTMS the presence of Val(1)-SIFamide in a second Homarus species, Homarus gammarus. In contrast, only the Gly(1) isoform was detected in the other astacideans investigated, including the lobster Nephrops norvegicus, a member of the same family as Homarus, and the crayfish Cherax quadricarinatus, P. clarkii and Pacifastacus leniusculus, which represent members of each of the extant families of freshwater astacideans. These results suggest that Val(1)-SIFamide may be a genus (Homarus)-specific isoform. Interestingly, both Val(1)- and Gly(1)-SIFamide possess an internal dibasic site, Arg(3)-Lys(4), raising the possibility of the ubiquitously conserved isoform PPFNGSIFamide. However, this octapeptide was not detected via MALDI-FTMS in any of the investigated species, and when applied to the isolated STNS of H. americanus possessed little bioactivity relative to the full-length Val(1) isoform. Thus, it appears that the dodeca-variants Val(1)- and Gly(1)-SIFamide are the sole bioactive isoforms of this peptide family in clawed lobsters and freshwater crayfish. PMID:18308319

  9. Development of a matrix-assisted laser desorption ionization mass spectrometric method for rapid process-monitoring of phthalocyanine compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yi-Ting, E-mail: ytchen@mail.cgu.edu.tw [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Molecular Medicine Research Center, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan (China); Wang, Fu-Shing [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Li, Zhendong [Department of Chemistry, University of Alberta, Alberta T6G 2G2 (Canada); Li Liang, E-mail: liang.li@ualberta.ca [Department of Chemistry, University of Alberta, Alberta T6G 2G2 (Canada); Ling, Yong-Chien, E-mail: ycling@mx.nthu.edu.tw [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2012-07-29

    Highlights: Black-Right-Pointing-Pointer MALDI TOFMS is developed as a rapid means of monitoring the process of phthalocyanine derivatives. Black-Right-Pointing-Pointer All-trans retinoic acid is used as matrix to reduce ion fragmentation and background formation. Black-Right-Pointing-Pointer Samples from the reaction process are taken for direct analysis by MALDI TOFMS without any cleanup. Black-Right-Pointing-Pointer The method is demonstrated for monitoring the synthesis of brominated Ni- and Cu-phthalocyanine. - Abstract: Phthalocyanines (PCs), an important class of chemicals widely used in many industrial sectors, are macrocyclic compounds possessing a heteroaromatic {pi}-electron system with optical properties influenced by chemical structures and impurities or by-products introduced during the synthesis process. Analytical tools allowing for rapid monitoring of the synthesis processes are of significance for the development of new PCs with improved performance in many application areas. In this work, we report a matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOFMS) method for rapid and convenient monitoring of PC synthesis reactions. For this class of compounds, intact molecular ions could be detected by MALDI using retinoic acid as matrix. It was shown that relative quantification results of two PC compounds could be generated by MALDI MS. This method was applied to monitor the bromination reactions of nickel- and copper-containing PCs. It was demonstrated that, compared to the traditional UV-visible method, the MALDI MS method offers the advantage of higher sensitivity while providing chemical species and relative quantification information on the reactants and products, which are crucial to process monitoring.

  10. Mass Spectrometric Analysis of the Cell Surface N-Glycoproteome by Combining Metabolic Labeling and Click Chemistry

    Science.gov (United States)

    Smeekens, Johanna M.; Chen, Weixuan; Wu, Ronghu

    2015-04-01

    Cell surface N-glycoproteins play extraordinarily important roles in cell-cell communication, cell-matrix interactions, and cellular response to environmental cues. Global analysis is exceptionally challenging because many N-glycoproteins are present at low abundances and effective separation is difficult to achieve. Here, we have developed a novel strategy integrating metabolic labeling, copper-free click chemistry, and mass spectrometry (MS)-based proteomics methods to analyze cell surface N-glycoproteins comprehensively and site-specifically. A sugar analog containing an azido group, N-azidoacetylgalactosamine, was fed to cells to label glycoproteins. Glycoproteins with the functional group on the cell surface were then bound to dibenzocyclooctyne-sulfo-biotin via copper-free click chemistry under physiological conditions. After protein extraction and digestion, glycopeptides with the biotin tag were enriched by NeutrAvidin conjugated beads. Enriched glycopeptides were deglycosylated with peptide- N-glycosidase F in heavy-oxygen water, and in the process of glycan removal, asparagine was converted to aspartic acid and tagged with 18O for MS analysis. With this strategy, 144 unique N-glycopeptides containing 152 N-glycosylation sites were identified in 110 proteins in HEK293T cells. As expected, 95% of identified glycoproteins were membrane proteins, which were highly enriched. Many sites were located on important receptors, transporters, and cluster of differentiation proteins. The experimental results demonstrated that the current method is very effective for the comprehensive and site-specific identification of the cell surface N-glycoproteome and can be extensively applied to other cell surface protein studies.

  11. Extraction chromatographic methods in the sample preparation sequence for thermal ionization mass spectrometric analysis of plutonium isotopes.

    Science.gov (United States)

    Grate, Jay W; O'Hara, Matthew J; Farawila, Anne F; Douglas, Matthew; Haney, Morgan M; Petersen, Steven L; Maiti, Tapas C; Aardahl, Christopher L

    2011-12-01

    A sample preparation sequence for actinide isotopic analysis by thermal ionization mass spectrometry (TIMS) is described that includes column-based extraction chromatography as the first separation step, followed by anion-exchange column separations. The sequence is designed to include a wet ashing step after the extraction chromatography to prevent any leached extractant or oxalic acid eluent reagents from interfering with subsequent separations, source preparation, or TIMS ionization. TEVA resin and DGA resin materials, containing extractants that consist only of C, N, O, and H atoms, were investigated for isolation of plutonium. Radiotracer level studies confirmed expected high yields from column-based separation procedures. Femtogram-level studies were carried out with TIMS detection, using multiple monoisotopic spikes applied sequentially throughout the separation sequence. Pu recoveries were 87% and 86% for TEVA and DGA resin separations, respectively. The Pu recoveries from 400 μL anion-exchange column separation sequences were 89% and 93% for trial sequences incorporating TEVA and DGA resin. Thus, a prior extraction chromatography step in the sequence did not interfere with the subsequent anion-exchange separation when a simple wet ash step was carried out in between these column separations. The average measurement efficiency for Pu, encompassing the chemical separation recoveries and the TIMS ionization efficiency, was 2.73% ± 0.77% (2σ) for the DGA resin trials and 2.67% ± 0.54% for the TEVA resin trials, compared to 3.41% and 2.37% (average 2.89%) for two control trials. These compare with an average measurement efficiency of 2.78% ± 1.70%, n = 33 from process benchmark analyses using Pu spikes processed through a sequence of oxalate precipitation, wet ash, iron hydroxide precipitation, and anion-exchange column separations. We conclude that extraction chromatography can be a viable separation procedure as part of a multistep sequence for TIMS

  12. Acetylation and glycation of fibrinogen in vitro occur at specific lysine residues in a concentration dependent manner: A mass spectrometric and isotope labeling study

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Jan, E-mail: jan.svensson@ki.se [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Bergman, Ann-Charlotte [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Adamson, Ulf [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Blombaeck, Margareta [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Wallen, Hakan; Joerneskog, Gun [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)

    2012-05-04

    Highlights: Black-Right-Pointing-Pointer Fibrinogen was incubated in vitro with glucose or aspirin. Black-Right-Pointing-Pointer Acetylations and glycations were found at twelve lysine sites by mass spectrometry. Black-Right-Pointing-Pointer The labeling by aspirin and glucose occurred dose-dependently. Black-Right-Pointing-Pointer No competition between glucose and aspirin for binding to fibrinogen was found. -- Abstract: Aspirin may exert part of its antithrombotic effects through platelet-independent mechanisms. Diabetes is a condition in which the beneficial effects of aspirin are less prominent or absent - a phenomenon called 'aspirin resistance'. We investigated whether acetylation and glycation occur at specific sites in fibrinogen and if competition between glucose and aspirin in binding to fibrinogen occurs. Our hypothesis was that such competition might be one explanation to 'aspirin resistance' in diabetes. After incubation of fibrinogen in vitro with aspirin (0.8 mM, 24 h) or glucose (100 mM, 5-10 days), we found 12 modified sites with mass spectrometric techniques. Acetylations in the {alpha}-chain: {alpha}K191, {alpha}K208, {alpha}K224, {alpha}K429, {alpha}K457, {alpha}K539, {alpha}K562, in the {beta}-chain: {beta}K233, and in the {gamma}-chain: {gamma}K170 and {gamma}K273. Glycations were found at {beta}K133 and {gamma}K75, alternatively {gamma}K85. Notably, the lysine 539 is a site involved in FXIII-mediated cross-linking of fibrin. With isotope labeling in vitro, using [{sup 14}C-acetyl]salicylic acid and [{sup 14}C]glucose, a labeling of 0.013-0.084 and 0.12-0.5 mol of acetylated and glycated adduct/mol fibrinogen, respectively, was found for clinically (12.9-100 {mu}M aspirin) and physiologically (2-8 mM glucose) relevant plasma concentrations. No competition between acetylation and glycation could be demonstrated. Thus, fibrinogen is acetylated at several lysine residues, some of which are involved in the cross-linking of

  13. Collision Cross-Section Determination and Tandem Mass Spectrometric Analysis of Isomeric Carotenoids Using Electrospray Ion Mobility Time-of-Flight Mass Spectrometry

    OpenAIRE

    Dong, Linlin; Shion, Henry; Davis, Roderick G.; Terry-Penak, Brent; Castro-Perez, Jose; van Breemen, Richard B

    2010-01-01

    Carotenoids are natural pigments with provitamin A and antioxidant activities. Biosynthesized in plants as their all-trans isomers, carotenoids isomerize in solution and in humans to multiple cis isomers which can have different bioavailabilities and functions. Since separation and characterization of isomeric carotenoids using HPLC or LC-MS-MS is time consuming, the potential for ion mobility mass spectrometry (IM-MS) to resolve and characterize carotenoid isomers rapidly without chromatogra...

  14. Ultra-sensitive Mass Spectrometric and Other Advanced Methods Applied to Biological Samples. Second interlaboratory comparison study for the analysis of 239Pu in synthetic urine at the μBq (∼100 aCi) level by mass spectrometry

    International Nuclear Information System (INIS)

    As a follow up to the initial 1998 intercomparison study, a second study was initiated in 2001 as part of the ongoing evaluation of the capabilities of various ultra-sensitive methods to analyze 239Pu in urine samples. The initial study was sponsored by the Department of Energy, Office of International Health Programs to evaluate and validate new technologies that may supersede the existing fission tract analysis (FTA) method for the analysis of 239Pu in urine at the μBq/l level. The ultra-sensitive techniques evaluated in the second study included accelerator mass spectrometry (AMS) by LLNL, thermal ionization mass spectrometry (TIMS) by LANL and FTA by the University of Utah. Only the results for the mass spectrometric methods will be presented. For the second study, the testing levels were approximately 4, 9, 29 and 56 μBq of 239Pu per liter of synthetic urine. Each test sample also contained 240Pu at a 240Pu/239Pu atom ratio of ∼0.15 and natural uranium at a concentration of 50 μBq/ml. From the results of the two studies, it can be inferred that the best performance at the μBq level is more laboratory specific than method specific. The second study demonstrated that LANL-TIMS and LLNL-AMS had essentially the same quantification level for both isotopes. Study results for bias and precision and acceptable performance compared to ANSI N13.30 and ANSI N42.22 have been compiled. (author)

  15. Mass spectrometric studies of cis- and trans-1a,3-disubstituted-1,1-dichloro-4-formyl-1a, 2,3,4-tetrahydro-1H-azirino [ 1,2-a ][ 1,5 ] benzodiazepines

    Institute of Scientific and Technical Information of China (English)

    XU, Jia-Xi(许家喜); ZHANG, Xin-Yu(张新宇); JIN, Sheng(金声)

    2000-01-01

    The mass spectrometric behaviour of four cis- and trans-1a,3- disubstituted -1,1 - dichloro-4-formyl-1a,2,3,4-tetrahydro1H-azirino[1,2-a] [1,5] benzodiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino[1,2-b][1,3]benzimidazole ions. These azirino[1,2-a] [1,5]-benzodiazepines can also eliminate HCl, or Cl plus HCl simultaneously to undergo a ring enlargement rearrangement to yield 1,6-benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions.

  16. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo ionization time-of-flight mass spectrometry: a new off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Directory of Open Access Journals (Sweden)

    J. Diab

    2015-01-01

    Full Text Available Source apportionment and exposure of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOA warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal/optical analyzer-photo ionization time of flight mass spectrometer (PI-TOFMS system, was developed. The approach extends the capability of the widely used PM carbon analysis (for elemental/organic carbon (EC / OC by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multiphoton ionization, REMPI and non-selective photo ionization (single photon ionization, SPI techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by electron ionization (EI aerosol mass spectrometer (AMS. Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during the thermal/optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermally breakdown products. In case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98 have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source for particulate matter

  17. Fast Direct Injection Mass-Spectrometric Characterization of Stimuli for Insect Electrophysiology by Proton Transfer Reaction-Time of Flight Mass-Spectrometry (PTR-ToF-MS

    Directory of Open Access Journals (Sweden)

    Franco Biasioli

    2012-03-01

    Full Text Available Electrophysiological techniques are used in insect neuroscience to measure the response of olfactory neurons to volatile odour stimuli. Widely used systems to deliver an olfactory stimulus to a test insect include airstream guided flow through glass cartridges loaded with a given volatile compound on a sorbent support. Precise measurement of the quantity of compound reaching the sensory organ of the test organism is an urgent task in insect electrophysiology. In this study we evaluated the performances of the recent realised proton transfer reaction-time of flight mass-spectrometry (PTR-ToF-MS as a fast and selective gas sensor. In particular, we characterised the gas emission from cartridges loaded with a set of volatile compounds belonging to different chemical classes and commonly used in electrophysiological experiments. PTR-ToF-MS allowed a fast monitoring of all investigated compounds with sufficient sensitivity and time resolution. The detection and the quantification of air contaminants and solvent or synthetic standards impurities allowed a precise quantification of the stimulus exiting the cartridge. The outcome of this study was twofold: on one hand we showed that PTR-ToF-MS allows monitoring fast processes with high sensitivity by real time detection of a broad number of compounds; on the other hand we provided a tool to solve an important issue in insect electrophysiology.

  18. Probing the dynamics of polyatomic multichannel elementary reactions by crossed molecular beam experiments with soft electron-ionization mass spectrometric detection.

    Science.gov (United States)

    Casavecchia, Piergiorgio; Leonori, Francesca; Balucani, Nadia; Petrucci, Raffaele; Capozza, Giovanni; Segoloni, Enrico

    2009-01-01

    In this Perspective we highlight developments in the field of chemical reaction dynamics. Focus is on the advances recently made in the investigation of the dynamics of elementary multichannel radical-molecule and radical-radical reactions, as they have become possible using an improved crossed molecular beam scattering apparatus with universal electron-ionization mass spectrometric detection and time-of-flight analysis. These improvements consist in the implementation of (a) soft ionization detection by tunable low-energy electrons which has permitted us to reduce interfering signals originating from dissociative ionization processes, usually representing a major complication, (b) different beam crossing-angle set-ups which have permitted us to extend the range of collision energies over which a reaction can be studied, from very low (a few kJ mol(-1), as of interest in astrochemistry or planetary atmospheric chemistry) to quite high energies (several tens of kJ mol(-1), as of interest in high temperature combustion systems), and (c) continuous supersonic sources for producing a wide variety of atomic and molecular radical reactant beams. Exploiting these new features it has become possible to tackle the dynamics of a variety of polyatomic multichannel reactions, such as those occurring in many environments ranging from combustion and plasmas to terrestrial/planetary atmospheres and interstellar clouds. By measuring product angular and velocity distributions, after having suppressed or mitigated, when needed, the problem of dissociative ionization of interfering species (reactants, products, background gases) by soft ionization detection, essentially all primary reaction products can be identified, the dynamics of each reaction channel characterized, and the branching ratios determined as a function of collision energy. In general this information, besides being of fundamental relevance, is required for a predictive description of the chemistry of these

  19. Spectrometric techniques 3

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume III presents the applications of spectrometric techniques to atmospheric and space studies. This book reviews the spectral data processing and analysis techniques that are of broad applicability.Organized into five chapters, this volume begins with an overview of the instrumentation used for obtaining field data. This text then reviews the contribution that space-borne spectroscopy in the thermal IR has made to the understanding of the planets. Other chapters consider the instruments that have recorded the planetary emission spectra. This book discusses as well

  20. In-house validation of a method for determination of silver nanoparticles in chicken meat based on asymmetric flow field-flow fractionation and inductively coupled plasma mass spectrometric detection

    DEFF Research Database (Denmark)

    Löschner, Katrin; Navratilova, Jana; Grombe, Ringo;

    2015-01-01

    spectrometric detection (AF4-ICP-MS) was applied for quantitative analysis of silver nanoparticles (AgNPs) in a chicken meat matrix following enzymatic sample preparation. For the first time an analytical validation of nanoparticle detection in a food matrix by AF4-ICP-MS has been carried out and the results......Nanomaterials are increasingly used in food production and packaging, and validated methods for detection of nanoparticles (NPs) in foodstuffs need to be developed both for regulatory purposes and product development. Asymmetric flow field-flow fractionation with inductively coupled plasma mass...... showed repeatable and intermediately reproducible determination of AgNP mass fraction and size. The findings demonstrated the potential of AF4-ICP-MS for quantitative analysis of NPs in complex food matrices for use in food monitoring and control. The accurate determination of AgNP size distribution...

  1. Spectrometric techniques 2

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume II provides information pertinent to vacuum ultraviolet techniques to complete the demonstration of the diversity of methods available to the spectroscopist interested in the ultraviolet visible and infrared spectral regions. This book discusses the specific aspects of the technique of Fourier transform spectroscopy.Organized into five chapters, this volume begins with an overview of the large number of systematic effects in the recording of an interferogram. This text then examines the design approach for a Fourier transform spectrometer with focus on optics.

  2. Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa

    OpenAIRE

    Signor, Luca; Boeri Erba, Elisabetta

    2013-01-01

    Effectively determining masses of proteins is critical to many biological studies (e.g. for structural biology investigations). Accurate mass determination allows one to evaluate the correctness of protein primary sequences, the presence of mutations and/or post-translational modifications, the possible protein degradation, the sample homogeneity, and the degree of isotope incorporation in case of labelling (e.g. 13C labelling). Electrospray ionisation (ESI) mass spectrometry (MS) is widely u...

  3. Quantitative determination of α-ionone, β-ionone, and β-damascenone and enantiodifferentiation of α-ionone in wine for authenticity control using multidimensional gas chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Langen, Johannes; Wegmann-Herr, Pascal; Schmarr, Hans-Georg

    2016-09-01

    Native concentrations of α-ionone, β-ionone, and β-damascenone were studied in various authentic and commercial wines. In addition, the enantiomeric distribution of α-ionone was determined and its merits as a potential marker for aroma adulteration in wine were discussed. For extraction of volatiles, headspace solid-phase microextraction (HS-SPME) was applied, followed by heart-cut multidimensional gas chromatography coupled to tandem mass spectrometric detection for trace-level analysis. The enantioselective analysis of α-ionone was achieved with octakis(2,3-di-O-pentyl-6-O-methyl)-γ-cyclodextrin as the chiral selector in the separation column for gas chromatography (GC). In all the authentic wines studied, α-ionone showed a high enantiomeric ratio in favor of the (R)-enantiomer. Since an illegal addition of α-ionone in a racemic form changes the enantiomeric ratio, this ratio may serve as an adulteration marker. Concentrations varied between authenticity markers in wine. PMID:27417694

  4. Quantitative determination of α-ionone, β-ionone, and β-damascenone and enantiodifferentiation of α-ionone in wine for authenticity control using multidimensional gas chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Langen, Johannes; Wegmann-Herr, Pascal; Schmarr, Hans-Georg

    2016-09-01

    Native concentrations of α-ionone, β-ionone, and β-damascenone were studied in various authentic and commercial wines. In addition, the enantiomeric distribution of α-ionone was determined and its merits as a potential marker for aroma adulteration in wine were discussed. For extraction of volatiles, headspace solid-phase microextraction (HS-SPME) was applied, followed by heart-cut multidimensional gas chromatography coupled to tandem mass spectrometric detection for trace-level analysis. The enantioselective analysis of α-ionone was achieved with octakis(2,3-di-O-pentyl-6-O-methyl)-γ-cyclodextrin as the chiral selector in the separation column for gas chromatography (GC). In all the authentic wines studied, α-ionone showed a high enantiomeric ratio in favor of the (R)-enantiomer. Since an illegal addition of α-ionone in a racemic form changes the enantiomeric ratio, this ratio may serve as an adulteration marker. Concentrations varied between authenticity markers in wine.

  5. Electronic states and nature of bonding of the molecule NiGe by all electron ab initio Hartree–Fock (HF) and configuration interaction (CI) calculations and mass spectrometric equilibrium experiments

    DEFF Research Database (Denmark)

    Shim, Irene; Kingcade, Joseph E.; Gingerich, Karl A.

    1988-01-01

    All electron ab initio Hartree–Fock (HF) and configuration interaction (CI) calculations have been applied to investigate the low-lying electronic states of the NiGe molecule. The ground state of the NiGe molecule is predicted to be 1Sigma+. The chemical bond in the 1Sigma+ ground state is a double...... bond composed of one sigma and one pi bond. The sigma bond is due to a delocalized molecular orbital formed by combining the Ni 4s and the Ge 4psigma orbitals. The pi bond is a partly delocalized valence bond, originating from the coupling of the 3dpi hole on Ni with the 4ppi electron on Ge. The low......-lying electronic states of the NiGe molecule have all been characterized by the symmetry of the hole in the 3d shell of Ni. The dissociation energy of the NiGe molecule has been determined from our high temperature mass spectrometric equilibrium data in combination with the theoretical results as D [open circle] 0...

  6. A sensitive liquid chromatographic-mass spectrometric method for simultaneous quantification of six iridoid glycosides from Zhi-zi-chi Decoction in rat plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Qu, Kankan; Dai, Jinna; Zhao, Longshan; Lu, Yanan; Li, Bin; Zhao, Xu; Hou, Pengyi; Zhang, Yuanting; Bi, Kaishun; Chen, Xiaohui

    2013-05-01

    A sensitive liquid chromatographic-mass spectrometric (LC-MS) method was developed and validated for simultaneous determination of geniposide, geniposidic acid, scandoside methyl ester, gardenoside, deacetyl asperulosidic acid methyl ester and genipin-1-β-gentiobioside after oral administration of Zhi-zi-chi Decoction in rat plasma. The six iridoid glycosides were extracted from plasma samples by protein precipitation, and then separated on an Apollo C18 column (250 mm × 4.6mm, 5 μm) through the application of a gradient elution. The analytes were monitored in positive electrospray ionization by selected ion monitoring mode (SIM). The lower limits of quantitation (LLOQ) of the six analytes were all lower than 6 ng/mL. The accuracy (relative error, RE%) was between -7.0% and 9.9%, while the intra- and inter-day precisions (relative standard deviation, RSD%) were less than 6.3% and 9.8% for the six analytes, respectively. The developed method was successfully applied to a comparative pharmacokinetic study of the six iridoids in rat plasma after oral administration of Zhi-zi-chi Decoction and Gardenia jasminoides extract.

  7. Mass-spectrometric identification of primary biological particle markers: indication for low abundance of primary biological material in the pristine submicron aerosol of Amazonia

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2011-07-01

    Full Text Available The abundance of marker compounds for primary biological particles in submicron aerosol was investigated by means of aerosol mass spectrometry. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker peaks were identified. The identified marker peaks were compared with mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the Central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker peaks places upper limits of 7.5 % for amino acids and 5.6 % for carbohydrates on the contribution of primary biological aerosol particles (PBAPs to the submicron organic aerosol mass concentration during this time period. Upper limits for the absolute submicron concentrations for both compound classes range from 0.01 to 0.1 μg m−3. Carbohydrates and protein amino acids make up for about two thirds of the dry mass of a biological cell. Thus, our findings suggest an upper limit for the PBAPs mass fraction of about 20 % to the submicron organic aerosol.

  8. Matrix effects on the multi-collector inductively coupled plasma mass spectrometric analysis of high-precision cadmium and zinc isotope ratios

    International Nuclear Information System (INIS)

    Resin-derived contaminants added to samples during column chemistry are shown to cause matrix effects that lead to inaccuracy in multi-collector inductively coupled plasma mass spectrometry measurement of small natural variations in Cd and Zn isotopic compositions. These matrix effects were evaluated by comparing pure Cd and Zn standards and standards doped with bulk column blank from the anion exchange chromatography procedure. Doped standards exhibit signal enhancements (Cd, Ag, Zn and Cu), instrumental mass bias changes and inaccurate isotopic compositions relative to undoped standards, all of which are attributed to the combined presence of resin-derived organics and inorganics. The matrix effect associated with the inorganic component of the column blanks was evaluated separately by doping standards with metals at the trace levels detected in the column blanks. Mass bias effects introduced by the inorganic column blank matrix are smaller than for the bulk column blank matrix but can still lead to significant changes in ion signal intensity, instrumental mass bias and isotopic ratios. Chemical treatment with refluxed HNO3 or HClO4/HNO3 removes resin-derived organic components resulting in matrix effects similar in magnitude to those associated with the inorganic component of the column blank. Mass bias correction using combined external normalization-SSB does not correct for these matrix effects because the instrumental mass biases experienced by Cd and Zn are decoupled from those of Ag and Cu, respectively. Our results demonstrate that ion exchange chromatography and associated resin-derived contaminants can be a source of error in MC-ICP-MS measurement of heavy stable element isotopic compositions

  9. 因子分析法在质谱成像数据分析中的应用%Application of Factor Analysis in Imaging Mass Spectrometric Data Analysis

    Institute of Scientific and Technical Information of China (English)

    陈一; 唐飞; 李铁刚; 贺玖明; 再帕尔·阿不力孜; 刘力涛; 王晓浩

    2014-01-01

    The factor analysis method applied in imaging mass spectrometry data analysis was studied. The imaging mass spectrometric data were obtained by air flow-assisted ionization imaging mass spectrometry method. The sample contained some symbols which were drawn on slides using three different inks ( red, blue, black) . The imaging data analyzed by factor analysis method were divided into the background, black, blue and red factor. The results showed that the scores of m/z=443. 2, 478. 4, 322. 2(344. 2) in red, blue, black factor respectively were much larger than others. Therefore, they were markers of three inks. The results accorded with actual condition well and proved that the application of factor analysis in imaging mass spectrometric data analysis was feasible. The data analysis results of factor analysis and principal component analysis were compared. The results showed that the target sample markers could be extracted by factor analysis simply and quantitatively. It was of great potential in biomarker extraction, diseases diagnose and pharmacological analysis.%对因子分析法在质谱成像数据分析中的应用进行了研究。本方法分析的质谱成像数据来源于空气动力辅助离子源质谱成像技术,所用样品为含有3种不同颜料(红色、蓝色、黑色)的笔迹样品。对该样品的成像数据进行因子分析后,将成像数据分为了背景、黑色、蓝色和红色因子。分析结果显示, m/z 443.2,478.4,322.2(344.2)分别在红色、蓝色、黑色因子中的贡献值远大于其它质荷比,因此是3种颜料的特征质荷比。此结果与实际情况相符,证明使用因子分析方法对质谱成像数据进行分析和特征提取是可行的。对因子分析与主成分分析的成像数据处理结果进行了比较,结果显示,因子分析可以更简单和定量地对特征质荷比进行取舍,在生物标志物提取、疾病诊断、药理分析等方面有较大的应用潜力。

  10. Combining asymmetrical flow field-flow fractionation with light-scattering and inductively coupled plasma mass spectrometric detection for characterization of nanoclay used in biopolymer nanocomposites

    DEFF Research Database (Denmark)

    Schmidt, Bjørn; Petersen, Jens Højslev; Koch, C. Bender;

    2009-01-01

    of clay nanoparticulates, an analytical system combining asymmetrical flow field-flow fractionation (AF4) with multi-angle light-scattering detection (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) is presented. In a migration study, we tested a biopolymer nanocomposite consisting...

  11. An ultra performance liquid chromatography-time-of-flight-mass spectrometric method for fast analysis of ginsenosides in Panax ginseng root

    NARCIS (Netherlands)

    Hu, C.; Kong, H.; Zhu, C.; Wei, H.; Hankemeier, T.; Greef, J. van der; Wang, M.; Xu, G.

    2011-01-01

    A method for fast analysis of ginsenosides in Panax ginseng roots was developed using ultra performance liquid chromatography-time-of-flight-mass spectrometry (UPLC-TOF-MS). The column used was HSS T3 (100 mm × 2.1 mm, 1.8 µm). The mobile phase consisted of 15 mmol/L ammonium formate and acetonitril

  12. Diagnosis and dosimetry of exposure to sulfur mustard: Development of a standard operating procedure for mass spectrometric analysis of haemoglobin adducts - Exploratory research on albumin and keratin adducts

    NARCIS (Netherlands)

    Noort, D.; Fidder, A.; Hulst, A.G.; Jong, L.P.A. de; Benschop, H.P.

    2000-01-01

    Experiments were carried out to develop a standard operating procedure for analysis of sulfur mustard adducts to the N-terminal valine in haemoglobin and to explore adduct formation with albumin and keratin. In the first approach, gas chromatography-negative chemical ionization/mass spectrometry (GC

  13. High temperature mass spectrometric studies on Ni-Te-O system: studies over the phase field NiO(s) + Ni2Te3O8(s)

    International Nuclear Information System (INIS)

    In order to generate thermodynamic data on tellurium compounds studies were carried out on M-Te-O ternary systems employing high temperature mass spectrometry. The vaporisation behaviour of NiO-Ni2 Te3O8 two-phase mixture has been studied and initial results are given

  14. Gas Chromatographic-Mass Spectrometric Analysis of Volatiles Obtained by Four Different Techniques from Salvia rosifolia Sm. and Evaluation for Biological Activity

    Science.gov (United States)

    Volatile constituents from the aerial parts of Salvia rosifolia Sm. (Lamiaceae), endemic to Turkey, were obtained by four different isolation techniques and then analyzed by gas chromatography (GC/FID) and gas chromatography – mass spectrometry (GC/MS) methods. Also in scope of the present work, the...

  15. Data correlation in on-line solid-phase extraction-gas chromatography-atomic emission/mass spectrometric detection of unknown microcontaminants

    NARCIS (Netherlands)

    Hankemeier, Th.; Rozenbrand, J.; Abhadur, M.; Vreuls, J.J.; Brinkman, U.A.Th.

    1998-01-01

    A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction (SPE) was coupled on-line to both GC system

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

    Science.gov (United States)

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

    2012-11-01

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

  17. Mass-spectrometric identification of binding proteins of Mr 25,000 protein, a part of vitellogenin B1, detected in particulate fraction of Xenopus laevis oocytes.

    Science.gov (United States)

    Sugimoto, Isamu; Li, Zhijun; Yoshitome, Satoshi; Ito, Susumu; Hashimoto, Eikichi

    2004-10-01

    A phosphorylated protein with molecular mass of 25,000 (pp25) is a component of Xenopus laevis vitellogenin B1. Our previous report showed the existence of several binding proteins of pp25 in the particulate fraction of Xenopus oocytes. In an attempt to elucidate the function of pp25, two of these binding proteins were purified, analyzed by mass-spectrometry, and identified as ribosomal proteins S13 and S14. Other binding proteins in the particulate fraction mostly corresponded to those derived from purified 40S and 60S ribosomal subunits, as shown by the overlay assay method. However, pp25 did not show any effect on protein synthesis in the rabbit reticulocyte lysate system. A model in which pp25 connects a type of serpin (serine protease inhibitor), the only pp25-binding protein detected in the cytoplasm, to the endoplasmic reticulum through two serine clusters is proposed to explain a possible function of this protein.

  18. Mass Spectrometric Identification of Si-O-H(g) Species from the Reaction of Silica with Water Vapor at Atmospheric Pressure

    Science.gov (United States)

    Opila, Elizabeth J.; Fox, Dennis S.; Jacobson, Nathan S.

    1997-01-01

    A high-pressure sampling mass spectrometer was used to detect the volatile species formed from SiO2 at temperatures between 1200C and 1400C in a flowing water vapor/oxygen gas mixture at 1 bar total pressure. The primary vapor species identified was Si(OH)4. The fragment ion Si(OH)3+,' was observed in quantities 3 to 5 times larger than the parent ion Si(OH)4+. The Si(OH)3+ intensity was found to have a small temperature dependence and to increase with the water vapor partial pressure as expected. In addition, SiO(OH)+ believed to be a fragment of SiO(OH)2, was observed. These mass spectral results were compared to the behavior of silicon halides.

  19. Mass spectrometric analytical services and research activities to support coal-liquid characterization research. Quarterly report, June 9, 1976--October 5, 1976. [10 refs

    Energy Technology Data Exchange (ETDEWEB)

    Scheppele, S.E.

    1976-10-19

    Low-resolution field ionization and high-resolution 70-eV electron-impact mass spectra data were obtained for 28 GPC fractions acquired from Bartlett, Kansas, heavy petroleum by members of the Separation and Characterization group at the Bartlesville Energy Research Center. This group was supplied with most-probable empirical formulas deduced from the high resolution electron-impact data. Analysis of the qualitative and quantitative analytical data previously obtained for GPC fractions from a Synthoil sample by high- and low-resolution field-ionization and high-resolution 70-eV electron-impact mass spectrometry is essentially complete. A study of field-ionization sensitivities for saturates and mixtures of saturates and aromatics is in progress. Components required to modify the combined FI/EI ion source to permit operation in the field desorption mode have been ordered.

  20. Matrix Assisted Laser Desorption Ionization Mass Spectrometric Analysis of Bacillus anthracis: From Fingerprint Analysis of the Bacterium to Quantification of its Toxins in Clinical Samples

    Science.gov (United States)

    Woolfitt, Adrian R.; Boyer, Anne E.; Quinn, Conrad P.; Hoffmaster, Alex R.; Kozel, Thomas R.; de, Barun K.; Gallegos, Maribel; Moura, Hercules; Pirkle, James L.; Barr, John R.

    A range of mass spectrometry-based techniques have been used to identify, characterize and differentiate Bacillus anthracis, both in culture for forensic applications and for diagnosis during infection. This range of techniques could usefully be considered to exist as a continuum, based on the degrees of specificity involved. We show two examples here, a whole-organism fingerprinting method and a high-specificity assay for one unique protein, anthrax lethal factor.

  1. Direct Analysis in Real Time by Mass Spectrometric Technique for Determining the Variation in Metabolite Profiles of Cinnamomum tamala Nees and Eberm Genotypes

    OpenAIRE

    Vineeta Singh; Atul Kumar Gupta; Singh, S.P.; Anil Kumar

    2012-01-01

    Cinnamomum tamala Nees & Eberm. is an important traditional medicinal plant, mentioned in various ancient literatures such as Ayurveda. Several of its medicinal properties have recently been proved. To characterize diversity in terms of metabolite profiles of Cinnamomum tamala Nees and Eberm genotypes, a newly emerging mass spectral ionization technique direct time in real time (DART) is very helpful. The DART ion source has been used to analyze an extremely wide range of phytochemicals pre...

  2. Mass spectrometric profiling of Bacillus cereus strains and quantitation of the emetic toxin cereulide by means of stable isotope dilution analysis and HEp-2 bioassay.

    Science.gov (United States)

    Stark, Timo; Marxen, Sandra; Rütschle, Andrea; Lücking, Genia; Scherer, Siegfried; Ehling-Schulz, Monika; Hofmann, Thomas

    2013-01-01

    A fast and robust high-throughput ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC-TOF MS) profiling method was developed and successfully applied to discriminate a total of 78 Bacillus cereus strains into no/low, medium and high producers of the emetic toxin cereulide. The data obtained by UPLC-TOF MS profiling were confirmed by absolute quantitation of cereulide in selected samples by means of high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) and stable isotope dilution assay (SIDA). Interestingly, the B. cereus strains isolated from four vomit samples and five faeces samples from patients showing symptoms of intoxication were among the group of medium or high producers. Comparison of HEp-2 bioassay data with those determined by means of mass spectrometry showed differences, most likely because the HEp-2 bioassay is based on the toxic action of cereulide towards mitochondria of eukaryotic cells rather than on a direct measurement of the toxin. In conclusion, the UPLC-electrospray ionization (ESI)-TOF MS and the HPLC-ESI-MS/MS-SIDA analyses seem to be promising tools for the robust high-throughput analysis of cereulide in B. cereus cultures, foods and other biological samples.

  3. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues.

  4. Headspace solid-phase microextraction-gas chromatography-quadrupole mass spectrometric methodology for the establishment of the volatile composition of Passiflora fruit species

    OpenAIRE

    Pontes, M.; Marques, J.C.; Câmara, J. S.

    2009-01-01

    Dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography-quadrupole mass spectrometry analysis (GC-qMS), was used to investigate the aroma profile of different species of passion fruit samples. The performance of five commercially available SPME fibres: 65 μm polydimethylsiloxane/divinylbenzene, PDMS/DVB; 100 μm polydimethylsiloxane, PDMS; 85 μm polyacrylate, PA; 50/30 μm divinylbenzene/carboxen on polydimethylsiloxane, DVB/CAR/PDMS (StableFlex...

  5. Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate...... to arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant...

  6. Characterization of national food agency shrimp and plaice reference materials for trace elements and arsenic species by atomic and mass spectrometric techniques

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pedersen, Gitte Alsing; McLaren, J. W.

    1997-01-01

    The National Food Agency (NFA) of Denmark has produced and characterized NFA Plaice and NFA Shrimp reference materials (RMs) for the control of the accuracy of trace element and arsenic species determinations in similar seafood samples, The physical preparation of the materials included dissection...... mass spectrometry (MS/MS) for qualitative verification, Based on a rigorous statistical analysis of the analytical data using the DANREF software, it was decided to assign certified values for mercury, cadmium and arsenic in the NFA Shrimp, and mercury, selenium and arsenic in the NFA Plaice...

  7. Semiconductor Nanomaterials-Based Fluorescence Spectroscopic and Matrix-Assisted Laser Desorption/Ionization (MALDI Mass Spectrometric Approaches to Proteome Analysis

    Directory of Open Access Journals (Sweden)

    Suresh Kumar Kailasa

    2013-12-01

    Full Text Available Semiconductor quantum dots (QDs or nanoparticles (NPs exhibit very unusual physico-chemcial and optical properties. This review article introduces the applications of semiconductor nanomaterials (NMs in fluorescence spectroscopy and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS for biomolecule analysis. Due to their unique physico-chemical and optical properties, semiconductors NMs have created many new platforms for investigating biomolecular structures and information in modern biology. These semiconductor NMs served as effective fluorescent probes for sensing proteins and cells and acted as affinity or concentrating probes for enriching peptides, proteins and bacteria proteins prior to MALDI-MS analysis.

  8. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues. PMID:23352828

  9. Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma.

    Science.gov (United States)

    Rood, Johannes J M; van Bussel, Mark T J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2016-09-15

    A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was performed in a range from 1 to 1000ng/ml, with the lowest level corresponding to the lower limit of quantitation. Gradient elution was performed on a 1.8μm particle trifunctional bonded C18 column by 1% (v/v) formic acid in water, and acetonitrile as mobile phase. The analyte was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer after positive ionization with the heated electrospray interface. Within-day precisions ranged from 3.4 to 10.3%, and between-day precisions from 3.8 to 10.4%, accuracies were 95.5-102.8%. Plasma (either lithium heparin or sodium EDTA) pretreatment was performed by salting-out assisted liquid-liquid extraction using acetonitrile and magnesium sulfate. This method was used to analyze the osimertinib blood plasma levels of five adult patients with metastatic T790M mutated non-small cellular lung carcinoma for therapeutic drug monitoring purposes. PMID:27469903

  10. On-line Mass Spectrometric Study of Heavy-Ion Induced Reactions at Energies up to 86 MeV/amu

    CERN Multimedia

    2002-01-01

    The aim of the experiment was to measure isotopic distributions of Li, Na, K, Rb, Cs and Fr as reaction fragments in heavy ion collisions. In order to get an overall view of the new energy range for heavy ions available from the SC, different energies and projectile-target combinations had to be studied. The data taking status is now finished. |1|2C and |1|8O beams were used in bombarding |1|2C, |9|3Nb, |1|8|1Ta and |2|3|8U in order to look at target fragmentation, projectile fragmentation and evaporative residues of spallation processes. The experimental apparatus is composed of three parts: \\item a)~A target-oven-ionizer assembly where selective thermal diffusion and selective surface ionization takes place in order to obtain a chemical separation of the reaction products. \\item b)~The mass spectrometer where the different-mass fragments are selected. \\item c)~An electrostatic ion beam line through which the fragments are transported to a low-background area where the detector (an electron multiplier) is lo...

  11. Highly specific purification of N-glycans using phosphate-based derivatization as an affinity tag in combination with Ti(4+)-SPE enrichment for mass spectrometric analysis.

    Science.gov (United States)

    Zhang, Ying; Peng, Ye; Bin, Zhichao; Wang, Huijie; Lu, Haojie

    2016-08-31

    N-linked protein glycosylation is involved in regulation of a wide variety of cellular processes and associated with numerous diseases. Highly specific identification of N-glycome remains a challenge while its biological significance is acknowledged. The relatively low abundance of glycan in complex biological mixtures, lack of basic sites for protonation, and suppression by other highly abundant proteins/peptides lead to the particularly poor detection sensitivity of N-glycans in the MS analysis. Therefore, the highly specific purification procedure becomes a crucial step prior to MS analysis of the N-glycome. Herein, a novel N-glycans enrichment approach based on phosphate derivatization combined with Ti(4+)-SPE (solid phase extraction) was developed. Briefly, in this strategy, N-glycans were chemically labeled with a phospho-group at their reducing ends, such that the Ti(4+)-SPE microspheres were able to capture the phospho-containing glycans. The enrichment method was developed and optimized using model oligosaccharides (maltoheptaose DP7 and sialylated glycan A1) and also glycans from a standard glycoprotein (asialofetuin, ASF). This method experimentally showed high derivatization efficiency (almost 100%), excellent selectivity (analyzing DP7 in the digests of bovine serum albumin at a mass ratio of 1:100), high enriching recovery (90%), good reproducibility (CVN-glycome in human serum, in which a total of 31 N-glycan masses were identified.

  12. 液质联用分析神经类固醇的衍生化方法%Derivatization in Liquid Chromatograhy/Mass Spectrometric Analysis of Neurosteroids

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances. However, some compounds do not show enough sensitivity in LC/MS and soft-ionization methods commonly used in LC/MS, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), sometimes do not give satisfactory structural information. This report presents an overview of the derivatization methods in the LC/MS analysis of neurosteroids or neuroactive neurosteroids, which are synthesized and accumulated in the nervous system. The derivatization of pregnenolone 3-sulfate, one of these steroids, with 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2,1,3-benzoxadiazole gave a satisfactory sensitivity during the quantitative analysis using LC/ESI-MS. The obtained results are much lower than those previously obtained using gas chromatography/mass spectrometry or radioimmunoassay. On the other hand, the derivatization to acetate was useful for the treatment of labile catechol estrogens in rat brains and gave enough structural information in LC/APCI-MS, which confirmed the existence of catechol estrogens in mammalian brains.

  13. Miniscale Liquid-Liquid Extraction Coupled with Full Evaporation Dynamic Headspace Extraction for the Gas Chromatography/Mass Spectrometric Analysis of Polycyclic Aromatic Hydrocarbons with 4000-to-14 000-fold Enrichment.

    Science.gov (United States)

    Liew, Christina Shu Min; Li, Xiao; Lee, Hian Kee

    2016-09-20

    A new sample preparation approach of combining a miniscale version of liquid-liquid extraction (LLE), termed miniscale-LLE (msLLE), with automated full evaporation dynamic headspace extraction (FEDHS) was developed. Its applicability was demonstrated in the extraction of several polycyclic aromatic hydrocarbons (PAHs) (acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene) from aqueous samples. In the first step, msLLE was conducted with 1.75 mL of n-hexane, and all of the extract was vaporized through a Tenax TA sorbent tube via a nitrogen gas flow, in the FEDHS step. Due to the stronger π-π interaction between the Tenax TA polymer and PAHs, only the latter, and not n-hexane, was adsorbed by the sorbent. This selectivity by the Tenax TA polymer allowed an effective concentration of PAHs while eliminating n-hexane by the FEDHS process. After that, thermal desorption was applied to the PAHs to channel them into a gas chromatography/mass spectrometric (GC/MS) system for analysis. Experimental parameters affecting msLLE (solvent volume and mixing duration) and FEDHS (temperature and duration) were optimized. The obtained results achieved low limits of detection (1.85-3.63 ng/L) with good linearity (r(2) > 0.9989) and high enrichment factors ranging from 4200 to 14 100. The optimized settings were applied to the analysis of canal water sampled from an industrial area and tap water, and this methodology was compared to stir-bar sorptive extraction (SBSE). This innovative combined extraction-concentration approach proved to be fast, effective, and efficient in determining low concentrations of PAHs in aqueous samples.

  14. A Validated High-Performance Liquid Chromatography-Tandem Mass Spectrometric (Lc-Ms/Ms Method for Simultaneous Determination of R(+-Ketorolac and S(−-Ketorolac in Human Plasma and Its Application to a Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Sabyasachi Patri

    2011-01-01

    Full Text Available We report a selective, accurate, and reproducible liquid chromatography-tandem mass spectrometric (LC-MS/MS method that employs solid phase extraction for quantification of ketorolac enantiomers in human plasma. Resolution of R(+-ketorolac and S(−-ketorolac was achieved using a Chiral-AGP column and a mobile phase of ammonium formate buffer (10 mM, pH 4.70±0.05:acetonitrile (85 : 15, v/v and 70 : 30, v/v in a gradient time program. S(+-etodolac was used as the internal standard (IS. Quantification was achieved using a positive electrospray ionization (ESI+ interface under multiple reaction monitoring (MRM condition. The method was validated over the concentration range of 9.36–1198.69 ng/ml for R(+-ketorolac and 6.07–776.74 ng/ml for S(−-ketorolac. Matrix effect was found negligible and the method showed good performances in terms of accuracy (89.6–102.7% and precision (1.7–6.7% for both enantiomers. Extraction recoveries of R(+-ketorolac, S(−-ketorolac, and S(+-etodolac were 82.04, 70.94, and 93.90%, respectively. Results of all stability exercises in human plasma were within acceptable limits. The method was successfully applied to a single dose cross over bioequivalence study in healthy human male volunteers. Incurred Sample Reanalysis (ISR was performed by randomly selecting 10% of total subject samples of the study using Statistical Analysis Software (SAS. Values of 91.1% for R (+-ketorolac and 83.5% for S(−-ketorolac indicated good acceptance for ISR.

  15. Validation of a liquid chromatography-triple quadrupole mass spectrometric method for the determination of 5-nitro-5'-hydroxy-indirubin-3'-oxime (AGM-130) in human plasma and its application to microdose clinical trial.

    Science.gov (United States)

    Park, Min-Ho; Lee, Yun Young; Cho, Kyung Hee; La, Sookie; Lee, Hee Joo; Yim, Dong-Seok; Ban, Sooho; Park, Moon-Young; Kim, Yong-Chul; Kim, Yoon-Gyoon; Shin, Young G

    2016-03-01

    A liquid chromatography-triple quadrupole mass spectrometric (LC-MS/MS) method was developed and validated for the determination of 5-nitro-5'-hydroxy-indirubin-3'-oxime (AGM-130) in human plasma to support a microdose clinical trial. The method consisted of a liquid-liquid extraction for sample preparation and LC-MS/MS analysis in the positive ion mode using TurboIonSpray(TM) for analysis. d3 -AGM-130 was used as the internal standard. A linear regression (weighted 1/concentration) was used to fit calibration curves over the concentration range of 10-2000 pg/mL for AGM-130. There were no endogenous interference components in the blank human plasma tested. The accuracy at the lower limit of quantitation was 96.6% with a precision (coefficient of variation, CV) of 4.4%. For quality control samples at 30, 160 and 1600 pg/mL, the between run CV was ≤5.0 %. Between-run accuracy ranged from 98.1 to 101.0%. AGM-130 was stable in 50% acetonitrile for 168 h at 4°C and 6 h at room temperature. AGM-130 was also stable in human plasma at room temperature for 6 h and through three freeze-thaw cycles. The variability of selected samples for the incurred sample reanalysis was ≤12.7% when compared with the original sample concentrations. This validated LC-MS/MS method for determination of AGM-130 was used to support a phase 0 microdose clinical trial. PMID:26139072

  16. Rapid identification of Burkholderia mallei and Burkholderia pseudomallei by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing

    Directory of Open Access Journals (Sweden)

    Karger Axel

    2012-10-01

    Full Text Available Abstract Background Burkholderia (B. pseudomallei and B. mallei are genetically closely related species. B. pseudomallei causes melioidosis in humans and animals, whereas B. mallei is the causative agent of glanders in equines and rarely also in humans. Both agents have been classified by the CDC as priority category B biological agents. Rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. Matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS has the potential of rapid and reliable identification of pathogens, but is limited by the availability of a database containing validated reference spectra. The aim of this study was to evaluate the use of MALDI-TOF MS for the rapid and reliable identification and differentiation of B. pseudomallei and B. mallei and to build up a reliable reference database for both organisms. Results A collection of ten B. pseudomallei and seventeen B. mallei strains was used to generate a library of reference spectra. Samples of both species could be identified by MALDI-TOF MS, if a dedicated subset of the reference spectra library was used. In comparison with samples representing B. mallei, higher genetic diversity among B. pseudomallei was reflected in the higher average Eucledian distances between the mass spectra and a broader range of identification score values obtained with commercial software for the identification of microorganisms. The type strain of B. pseudomallei (ATCC 23343 was isolated decades ago and is outstanding in the spectrum-based dendrograms probably due to massive methylations as indicated by two intensive series of mass increments of 14 Da specifically and reproducibly found in the spectra of this strain. Conclusions Handling of pathogens under BSL 3 conditions is dangerous and cumbersome but can be minimized by inactivation of bacteria with ethanol, subsequent protein extraction under BSL 1 conditions and MALDI-TOF MS

  17. Headspace solid-phase microextraction-gas chromatographic-time-of-flight mass spectrometric methodology for geographical origin verification of coffee

    International Nuclear Information System (INIS)

    Increasing consumer awareness of food safety issues requires the development of highly sophisticated techniques for the authentication of food commodities. The food products targeted for falsification are either products of high commercial value or those produced in large quantities. For this reason, the present investigation is directed towards the characterization of coffee samples according to the geographical origin. The conducted research involves the development of a rapid headspace solid-phase microextraction (HS-SPME)-gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) method that is utilized for the verification of geographical origin traceability of coffee samples. As opposed to the utilization of traditional univariate optimization methods, the current study employs the application of multivariate experimental designs to the optimization of extraction-influencing parameters. Hence, the two-level full factorial first-order design aided in the identification of two influential variables: extraction time and sample temperature. The optimum set of conditions for the two variables was 12 min and 55 deg. C, respectively, as directed by utilization of Doehlert matrix and response surface methodology. The high-throughput automated SPME procedure was completed by implementing a single divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) 50/30 μm metal fiber with excellent durability properties ensuring the completion of overall sequence of coffee samples. The utilization of high-speed TOFMS instrument ensured the completion of one GC-MS run of a complex coffee sample in 7.9 min and the complete list of benefits provided by ChromaTOF software including fully automated background subtraction, baseline correction, peak find and mass spectral deconvolution algorithms was exploited during the data evaluation procedure. The combination of the retention index (RI) system using C8-C40 alkanes and the mass spectral library search was utilized for the

  18. The use of matrix coating assisted by an electric field (MCAEF) to enhance mass spectrometric imaging of human prostate cancer biomarkers.

    Science.gov (United States)

    Wang, Xiaodong; Han, Jun; Hardie, Darryl B; Yang, Juncong; Borchers, Christoph H

    2016-01-01

    In this work, we combined a newly developed matrix coating technique - matrix coating assisted by an electric field (MCAEF) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to enhance the imaging of peptides and proteins in tissue specimens of human prostate cancer. MCAEF increased the signal-to-noise ratios of the detected proteins by a factor of 2 to 5, and 232 signals were detected within the m/z 3500-37500 mass range on a time-of-flight mass spectrometer and with the sinapinic acid MALDI matrix. Among these species, three proteins (S100-A9, S100-A10, and S100-A12) were only observed in the cancerous cell region and 14 proteins, including a fragment of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 2, a fragment of cAMP-regulated phosphoprotein 19, 3 apolipoproteins (C-I, A-I, and A-II), 2 S100 proteins (A6 and A8), β-microseminoprotein, tumor protein D52, α-1-acid glycoprotein 1, heat shock protein β-1, prostate-specific antigen, and 2 unidentified large peptides at m/z 5002.2 and 6704.2, showed significantly differential distributions at the p < 0.05 (t-test) level between the cancerous and the noncancerous regions of the tissue. Among these 17 species, the distributions of apolipoprotein C-I, S100-A6, and S100-A8 were verified by immunohistological staining. In summary, this study resulted in the imaging of the largest group of proteins in prostate cancer tissues by MALDI-MS reported thus far, and is the first to show a correlation between S100 proteins and prostate cancer in a MS imaging study. The successful imaging of the three proteins only found in the cancerous tissues, as well as those showing differential expressions demonstrated the potential of MCAEF-MALDI/MS for the in situ detection of potential cancer biomarkers. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Methylenedioxy designer drugs: mass spectrometric characterization of their glutathione conjugates by means of liquid chromatography-high-resolution mass spectrometry/mass spectrometry and studies on their glutathionyl transferase inhibition potency.

    Science.gov (United States)

    Meyer, Markus R; Richter, Lilian H J; Maurer, Hans H

    2014-04-25

    Methylenedioxy designer drugs of abuse such as 3,4-methylenedioxymethamphetamine (MDMA) can be selectively toxic to serotonergic neurons and glutathione (GSH) adducts have been implicated in its neurotoxicity. The catecholic demethylenyl metabolites of MDMA, 3,4-dihydroxymethamphetamine and 3,4-dihydroxyamphetamine, are metabolically oxidized to the corresponding ortho-quinones, which are highly reactive intermediates. These intermediates can then be conjugated with GSH preventing cellular damage. Furthermore, glutathionyl transferase (GST) activity was described to be irreversibly inhibited by the catechols dopamine, α-methyldopa and their GSH conjugates. Therefore, the aims of the present work were the detection and characterization of GSH conjugates of ten methylenedioxy drugs of abuse and their phase I metabolites as well as to assess their inhibition potency on GST activity. The substrates were incubated using human placental GST with or without preincubation by cytochrome P450 enzymes preparations. GST inhibition was tested using chlorodinitrobenzene GSH conjugation as marker reaction. GSH conjugates were analyzed and characterized using LC-high-resolution-MS/MS. For confirmation of postulated fragmentation patterns, formation of GSH conjugates of selected deuterated analogs (deuterated analogue approach, DAA) of the investigated drugs was explored. For the methylenedioxy amphetamines the following steps could be identified: conjugation of the parent compounds at position 2, 5, 6, of the demethylenyl metabolites at position 2 and 5, and of the further deaminated demethylenyl metabolites at position 2. For the β-keto-phenylalkylamine and pyrrolidinophenone, conjugation of the demethylenyl metabolites and of the deaminated demethylenyl metabolites at position 2 could be identified. The DAA allowed the differentiation of the 2 and 5/6 isomers by confirmation of the postulated mass spectral fragments. Finally, the tested drugs and phase I metabolites showed no

  20. Sample preparation for inductively coupled plasma mass spectrometric determination of the zinc-70 to zinc-68 isotope ratio in biological samples

    International Nuclear Information System (INIS)

    Sample preparation was optimized for the 70Zn:68Zn isotope ratio determinations performed with inductively coupled plasma mass spectrometry in blood, faeces and urine from human pre-term babies after oral or intravenous administration of enriched 70Zn. The preparation techniques achieved complete decomposition, matrix separation, maximum preconcentration and minimum contamination. After sample decomposition, Zn was extracted into CCl4 with ammonium pyrrolidin-1-yldithioformate and back extracted into 1.2 mol dm-3 HNO3 for analysis. Residual chloride resulting from dissolved CCl4 in the acid led to interference by 35Cl2+, and the procedure was modified to evaporate the CCl4. Extraction was unnecessary for faecal samples. Under optimized conditions the 70Zn:68Zn isotope ratio can be measured with acceptable precision (200 ng cm-3 in the analytical solution). (Author)

  1. Main differences between volatiles of sparkling and base wines accessed through comprehensive two dimensional gas chromatography with time-of-flight mass spectrometric detection and chemometric tools.

    Science.gov (United States)

    Welke, Juliane Elisa; Zanus, Mauro; Lazzarotto, Marcelo; Pulgati, Fernando Hepp; Zini, Cláudia Alcaraz

    2014-12-01

    The main changes in the volatile profile of base wines and their corresponding sparkling wines produced by traditional method were evaluated and investigated for the first time using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) and chemometric tools. Fisher ratios helped to find the 119 analytes that were responsible for the main differences between base and sparkling wines and principal component analysis explained 93.1% of the total variance related to the selected 78 compounds. It was also possible to observe five subclusters in base wines and four subclusters in sparkling wines samples through hierarchical cluster analysis, which seemed to have an organised distribution according to the regions where the wines came from. Twenty of the most important volatile compounds co-eluted with other components and separation of some of them was possible due to GC×GC/TOFMS performance.

  2. Detection and quantification of some plant growth regulators in a seaweed-based foliar spray employing a mass spectrometric technique sans chromatographic separation.

    Science.gov (United States)

    Prasad, Kamalesh; Das, Arun Kumar; Oza, Mihir Deepak; Brahmbhatt, Harshad; Siddhanta, Arup Kumar; Meena, Ramavatar; Eswaran, Karuppanan; Rajyaguru, Mahesh Rameshchandra; Ghosh, Pushpito Kumar

    2010-04-28

    The sap expelled from the fresh harvest of Kappaphycus alvarezii , a red seaweed growing in tropical waters, has been reported to be a potent foliar spray. Tandem mass spectrometry of various organic extracts of the sap confirmed the presence of the plant growth regulators (PGRs) indole 3-acetic acid, gibberellin GA(3), kinetin, and zeatin. These PGRs were quantified in fresh state and after 1 year of storage by ESI-MS without recourse to chromatographic separation. Quantification was validated against HPLC data. The results may be useful in correlating with the efficacy of the sap. The methodology was extended to two other seaweeds. The method developed is convenient and precise and may find application in other agricultural formulations containing these growth hormones.

  3. Preparation of porous styrenics-based monolithic layers for thin layer chromatography coupled with matrix-assisted laser-desorption/ionization time-of-flight mass spectrometric detection.

    Science.gov (United States)

    Lv, Yongqin; Lin, Zhixing; Tan, Tianwei; Svec, Frantisek

    2013-11-01

    Monolithic 50 μm thin poly(4-methylstyrene-co-chloromethylstyrene-co-divinylbenzene) layers attached to 6.0 cm × 3.3 cm glass plates have been prepared, using a thermally initiated polymerization process. These layers had a well-defined porous structure with a globular morphology demonstrated with SEM images and exhibited superhydrophobic properties characterized with a water contact angle of 157°. They were then used for thin-layer chromatography of peptides and proteins fluorescently labeled with fluorescamine. The spots of individual separated compounds were visualized using UV light, and their identities were confirmed with a matrix-assisted laser desorption/ionization time of flight mass spectrometry. The presence of chloromethylstyrene units in the polymer enabled hypercrosslinking via a Friedel-Crafts alkylation reaction, and led to monoliths with much larger surface areas, which were suitable for separations of small dye molecules.

  4. Speciation analysis of 129I in seawater by carrier-free AgI-AgCl coprecipitation and accelerator mass spectrometric measurement

    DEFF Research Database (Denmark)

    Luo, Maoyi; Hou, Xiaolin; He, Chaohui;

    2013-01-01

    A rapid and simple method was developed for speciation analysis of 129I in seawater by selective coprecipitation of carrier-free iodide and accelerator mass spectrometry (AMS) measurement of 129I. Iodide was separated from seawater and other species of iodine by coprecipitation of AgI with Ag2SO3...... is higher than 70%. Six seawater samples collected from the Norwegian Sea were analyzed by this method as well as a conventional anion-exchange chromatographic method; the results from the two methods show no significant difference (p = 0.05). Because only one separation step and fewer chemicals...... are involved in the procedure, this method is suitable for operation on board sampling vessels, as it avoids the transport of samples to the laboratory and storage for a longer time before analysis, therefore significantly improving the analytical capacity and reliability of speciation analysis of 129I...

  5. Fluorinated carbon tag derivatization combined with fluorous solid-phase extraction: a new method for the highly sensitive and selective mass spectrometric analysis of glycans.

    Science.gov (United States)

    Li, Lulu; Jiao, Jing; Cai, Yan; Zhang, Ying; Lu, Haojie

    2015-01-01

    The sensitive and specific detection of glycans via mass spectrometry (MS) remains a significant challenge due to their low abundance in complex biological mixtures, inherent lack of hydrophobicity, and suppression by other, more abundant biological molecules (proteins/peptides) or contaminants. A new strategy for the sensitive and selective MS analysis of glycans based on fluorous chemistry is reported. Glycan reducing ends were derivatized with a hydrophobic fluorinated carbon tag, increasing glycan ionization efficiency during MS by more than an order of magnitude. More importantly, the fluorinated carbon tag enabled efficient fluorous solid-phase extraction (FSPE) to specifically enrich the glycans from contaminated solutions and protein mixtures. Finally, we successfully analyzed the N-glycome in human serum using this new method. PMID:25884104

  6. Development of a portable mass spectrometric system for determination of isotopic composition of solid uranium samples using fluorine volatilization. Final report

    International Nuclear Information System (INIS)

    Using hardware and materials supplied by LANL, a prototype quadrupole mass spectrometer system designed for portable field analysis of isotopic composition of solid uranium samples was assembled and tested. The system contained the capability for fluorine volatilization of solid uranium samples with gas introduction, which was successfully tested and demonstrated using 100 mg samples of U3O8. Determination of precision and accuracy for measuring isotopic composition was performed using isotopic standards. Use with soil samples containing uranium were also attempted. Silicates in the soil forming SiF4 were found to be a kinetic bottleneck to the formation of UF6. This could be avoided by performing some sort of chemical separation as a pre-treatment step, which was demonstrated using nitric acid

  7. Coumarins as new matrices for matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of hydrophobic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hang, E-mail: hangwang@sjtu.edu.cn [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Dai, Bona [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Liu, Bin [Key Laboratory of Kidney Disease Pathogenesis and Intervention of Hubei Province, College of Medicine, Hubei Polytechnic University, Huangshi, Hubei 435003 (China); Lu, Han [Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), 197, Rui Jin Er Road, Shanghai 200025 (China)

    2015-07-02

    Highlights: • Coumarins were used as new MALDI matrices. • Coumarins were used for MALDI-FT ICR MS detection of hydrophobic compounds. • DCA had improvement in detection sensitivity, stability, selectivity and reproducibility. • DCA was applied to sterols detection in yeast cells. - Abstract: Hydrophobic compounds with hydroxyl, aldehyde or ketone groups are generally difficult to detect using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), because these compounds have low proton affinity and are poorly ionized by MALDI. Herein, coumarins have been used as new matrices for MALDI-MS analysis of a variety of hydrophobic compounds with low ionization efficiency, including steroids, coenzyme Q10, a cyclic lipopeptide and cholesterol oleate. Five coumarins, including coumarin, umbelliferone, esculetin, 7-hydroxycoumarin-3-carboxylic acid (HCA) and 6,7-dihydroxycoumarin-3-carboxylic acid (DCA), were compared with the conventional matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA). Coumarins with hydroxyl or carboxylic acid groups enabled detection. Taking DCA as an example, this matrix proved to be superior to DHB or CHCA in detection sensitivity, stability, spot-to-spot and sample-to-sample reproducibility, and accuracy. DCA increased the stability of the target compounds and decreased the loss of water. The [M + Na]{sup +} peaks were observed for all target compounds by adding NaCl as an additive, and the [M − H{sub 2}O + H]{sup +} and [M + H]{sup +} peaks decreased. DCA was selected for the identification of sterols in yeast cells, and thirteen sterols were detected by Fourier transform ion cyclotron resonance (FT ICR) mass spectrometry. This work demonstrates the potential of DCA as a new matrix for detection of hydrophobic molecules by MALDI-MS and provides an alternative tool for screening sterols in antifungal research.

  8. Quantitation of donepezil and its active metabolite 6-O-desmethyl donepezil in human plasma by a selective and sensitive liquid chromatography-tandem mass spectrometric method

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Bhavin N. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India); Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sharma, Naveen [Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sanyal, Mallika [Chemistry Department, St. Xaviers' College, Navrangpura, Ahmedabad 380 009, Gujarat (India); Shrivastav, Pranav S. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India)], E-mail: pranav_shrivastav@yahoo.com

    2008-11-23

    A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous determination of donepezil (D) and its pharmacologically active metabolite, 6-O-desmethyl donepezil (6-ODD) in human plasma is developed using galantamine as internal standard (IS). The analytes and IS were extracted from 500 {mu}L aliquots of human plasma via solid-phase extraction (SPE) on Waters Oasis HLB cartridges. Chromatographic separation was achieved in a run time of 6.0 min on a Waters Novapak C18 (150 mm x 3.9 mm, 4 {mu}m) column under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for D, 6-ODD and IS were at m/z 380.1 {yields} 91.2, 366.3 {yields} 91.3 and 288.2 {yields} 213.2, respectively. The method was fully validated for its selectivity, interference check, sensitivity, linearity, precision and accuracy, recovery, matrix effect, ion suppression/enhancement, cross-specificity, stability and dilution integrity. A linear dynamic range of 0.10-50.0 ng mL{sup -1} for D and 0.02-10.0 ng mL{sup -1} for 6-ODD was evaluated with mean correlation coefficient (r) of 0.9975 and 0.9985, respectively. The intra-batch and inter-batch precision (%CV, coefficient of variation) across five quality control levels was less than 7.5% for both the analytes. The method was successfully applied to a bioequivalence study of 10 mg donepezil tablet formulation in 24 healthy Indian male subjects under fasting condition.

  9. Coumarins as new matrices for matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of hydrophobic compounds

    International Nuclear Information System (INIS)

    Highlights: • Coumarins were used as new MALDI matrices. • Coumarins were used for MALDI-FT ICR MS detection of hydrophobic compounds. • DCA had improvement in detection sensitivity, stability, selectivity and reproducibility. • DCA was applied to sterols detection in yeast cells. - Abstract: Hydrophobic compounds with hydroxyl, aldehyde or ketone groups are generally difficult to detect using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), because these compounds have low proton affinity and are poorly ionized by MALDI. Herein, coumarins have been used as new matrices for MALDI-MS analysis of a variety of hydrophobic compounds with low ionization efficiency, including steroids, coenzyme Q10, a cyclic lipopeptide and cholesterol oleate. Five coumarins, including coumarin, umbelliferone, esculetin, 7-hydroxycoumarin-3-carboxylic acid (HCA) and 6,7-dihydroxycoumarin-3-carboxylic acid (DCA), were compared with the conventional matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA). Coumarins with hydroxyl or carboxylic acid groups enabled detection. Taking DCA as an example, this matrix proved to be superior to DHB or CHCA in detection sensitivity, stability, spot-to-spot and sample-to-sample reproducibility, and accuracy. DCA increased the stability of the target compounds and decreased the loss of water. The [M + Na]+ peaks were observed for all target compounds by adding NaCl as an additive, and the [M − H2O + H]+ and [M + H]+ peaks decreased. DCA was selected for the identification of sterols in yeast cells, and thirteen sterols were detected by Fourier transform ion cyclotron resonance (FT ICR) mass spectrometry. This work demonstrates the potential of DCA as a new matrix for detection of hydrophobic molecules by MALDI-MS and provides an alternative tool for screening sterols in antifungal research

  10. A critical assessment of the performance criteria in confirmatory analysis for veterinary drug residue analysis using mass spectrometric detection in selected reaction monitoring mode.

    Science.gov (United States)

    Berendsen, Bjorn J A; Meijer, Thijs; Wegh, Robin; Mol, Hans G J; Smyth, Wesley G; Armstrong Hewitt, S; van Ginkel, Leen; Nielen, Michel W F

    2016-05-01

    Besides the identification point system to assure adequate set-up of instrumentation, European Commission Decision 2002/657/EC includes performance criteria regarding relative ion abundances in mass spectrometry and chromatographic retention time. In confirmatory analysis, the relative abundance of two product ions, acquired in selected reaction monitoring mode, the ion ratio should be within certain ranges for confirmation of the identity of a substance. The acceptable tolerance of the ion ratio varies with the relative abundance of the two product ions and for retention time, CD 2002/657/EC allows a tolerance of 5%. Because of rapid technical advances in analytical instruments and new approaches applied in the field of contaminant testing in food products (multi-compound and multi-class methods) a critical assessment of these criteria is justified. In this study a large number of representative, though challenging sample extracts were prepared, including muscle, urine, milk and liver, spiked with 100 registered and banned veterinary drugs at levels ranging from 0.5 to 100 µg/kg. These extracts were analysed using SRM mode using different chromatographic conditions and mass spectrometers from different vendors. In the initial study, robust data was collected using four different instrumental set-ups. Based on a unique and highly relevant data set, consisting of over 39 000 data points, the ion ratio and retention time criteria for applicability in confirmatory analysis were assessed. The outcomes were verified based on a collaborative trial including laboratories from all over the world. It was concluded that the ion ratio deviation is not related to the value of the ion ratio, but rather to the intensity of the lowest product ion. Therefore a fixed ion ratio deviation tolerance of 50% (relative) is proposed, which also is applicable for compounds present at sub-ppb levels or having poor ionisation efficiency. Furthermore, it was observed that retention time

  11. A critical assessment of the performance criteria in confirmatory analysis for veterinary drug residue analysis using mass spectrometric detection in selected reaction monitoring mode.

    Science.gov (United States)

    Berendsen, Bjorn J A; Meijer, Thijs; Wegh, Robin; Mol, Hans G J; Smyth, Wesley G; Armstrong Hewitt, S; van Ginkel, Leen; Nielen, Michel W F

    2016-05-01

    Besides the identification point system to assure adequate set-up of instrumentation, European Commission Decision 2002/657/EC includes performance criteria regarding relative ion abundances in mass spectrometry and chromatographic retention time. In confirmatory analysis, the relative abundance of two product ions, acquired in selected reaction monitoring mode, the ion ratio should be within certain ranges for confirmation of the identity of a substance. The acceptable tolerance of the ion ratio varies with the relative abundance of the two product ions and for retention time, CD 2002/657/EC allows a tolerance of 5%. Because of rapid technical advances in analytical instruments and new approaches applied in the field of contaminant testing in food products (multi-compound and multi-class methods) a critical assessment of these criteria is justified. In this study a large number of representative, though challenging sample extracts were prepared, including muscle, urine, milk and liver, spiked with 100 registered and banned veterinary drugs at levels ranging from 0.5 to 100 µg/kg. These extracts were analysed using SRM mode using different chromatographic conditions and mass spectrometers from different vendors. In the initial study, robust data was collected using four different instrumental set-ups. Based on a unique and highly relevant data set, consisting of over 39 000 data points, the ion ratio and retention time criteria for applicability in confirmatory analysis were assessed. The outcomes were verified based on a collaborative trial including laboratories from all over the world. It was concluded that the ion ratio deviation is not related to the value of the ion ratio, but rather to the intensity of the lowest product ion. Therefore a fixed ion ratio deviation tolerance of 50% (relative) is proposed, which also is applicable for compounds present at sub-ppb levels or having poor ionisation efficiency. Furthermore, it was observed that retention time

  12. Expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution/high accuracy mass spectrometric detection of stanozolol glucuronides in human sports drug testing.

    Science.gov (United States)

    Schänzer, Wilhelm; Guddat, Sven; Thomas, Andreas; Opfermann, Georg; Geyer, Hans; Thevis, Mario

    2013-01-01

    Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3'-OH-stanozolol glucuronide in sports drug testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3'-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3'-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the drug. Applying the established

  13. Mass spectrometric determination of thorium and uranium in human hair and nails in a high background natural radiation area of Serbia

    International Nuclear Information System (INIS)

    The content of elements in human hair and nails can be considered as alternative bio-indicators of public exposure to natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their presence in other tissues of body. Hair and nails were collected from a high natural background radiation area in Serbia to analyze the concentration of thorium, uranium and selected trace elements such as Mn, Ni, Cu, Sr, Cd, and Cs using inductively coupled plasma mass spectrometry. Th and U concentrations in hair varied from 0.0002 to 0.0276 μg/g and 0.0002 to 0.0771 μg/g, respectively. The concentration in nail varied from 0.0023 to 0.0564 μg/g and 0.0025 to 0.0447 μg/g, for Th and U, respectively. There was a large variation for other metal's concentrations in hair, which may be due to different geological origin and anthropogenic activities. (author)

  14. Displacement solid-phase extraction on mercapto-functionalized magnetite microspheres for inductively coupled plasma mass spectrometric determination of trace noble metals

    International Nuclear Information System (INIS)

    A flow injection online displacement solid-phase extraction (DSPE) via magnetic immobilization of mercapto-functionalized magnetite microspheres onto the inner walls of a knotted reactor (KR) coupled with inductively coupled plasma mass spectrometry was developed for selective preconcentration and determination of trace noble metals (Ru, Rh, Pd, Pt, Ir and Au) in complex matrices. Online DSPE of 2.7 mL aqueous solution gave the enhancement factors of 32-46 for the six noble metals in comparison with direct nebulization of aqueous sample solution, and the detection limits (3 s) of 2.1 ng L-1 for Ru, 1.9 ng L-1 for Rh, 2.5 ng L-1 for Pd, 1.8 ng L-1 for Ir, 1.9 ng L-1 for Pt and 1.7 ng L-1 for Au. The sample throughput of the developed method was about 20 samples h-1, and the relative standard deviation for eleven replicate determinations of the noble metals at the 30 ng L-1 level ranged from 1.2% to 2.1%. The recoveries of Ru, Rh, Pd, Pt, Ir and Au still maintained 90% even after successive 140 cycles of DSPE. The developed method was successfully applied to selective determination of trace Ru, Rh, Pd, Pt, Ir and Au in complex matrices.

  15. Development and validation of a supercritical fluid chromatography method for the direct determination of enantiomeric purity of provitamin B5 in cosmetic formulations with mass spectrometric detection.

    Science.gov (United States)

    Khater, Syame; West, Caroline

    2015-01-01

    A rapid and efficient chiral supercritical fluid chromatography (SFC) method has been developed for the quantitative determination of panthenol enantiomers in cosmetic formulations (cream, lotion, wipe, and exfoliant). Indeed, the pharmacological effect only depends on the D form (Dexpanthenol) thus accurate measurement of its enantiomeric purity in formulated cosmetic products is of interest. The samples were prepared with liquid-liquid extraction followed by solid-phase extraction on Adsorbex amino cartridges. After testing several enantioselective columns in an attempt at reversing the elution order to have the minor enantiomer eluted first, the best separation of enantiomers and internal standard (N-acetyl-L-alanine) was achieved on a 3 μm-amylose-type immobilized polysaccharide chiral stationary phase (Chiralpak IA) in less than 6 min with a simple mobile phase comprising carbon dioxide and 11% methanol pumped at 2.3 mL/min, 25°C and 150 bar backpressure. Supercritical fluid chromatography coupled to both an optical diode-array detector and a user-friendly single-quadrupole mass spectrometer (Waters QDa) equipped with electrospray ionization source has been used. The on-line coupling ensures the technique to be more informative and improves detection sensitivity, as underivatized panthenol has a poor UV absorption. The limit of quantification (LOQ) achieved with single-ion recording was 0.5 μg/mL. The method was validated in terms of linearity, precision and accuracy and satisfactory results were obtained. PMID:25459930

  16. Ca(2+) -complex stability of GAPAGPLIVPY peptide in gas and aqueous phase, investigated by affinity capillary electrophoresis and molecular dynamics simulations and compared to mass spectrometric results.

    Science.gov (United States)

    Nachbar, Markus; El Deeb, Sami; Mozafari, Mona; Alhazmi, Hassan A; Preu, Lutz; Redweik, Sabine; Lehmann, Wolf Dieter; Wätzig, Hermann

    2016-03-01

    Strong, sequence-specific gas-phase bindings between proline-rich peptides and alkaline earth metal ions in nanoESI-MS experiments were reported by Lehmann et al. (Rapid Commun. Mass Spectrom. 2006, 20, 2404-2410), however its relevance for physiological-like aqueous phase is uncertain. Therefore, the complexes should also be studied in aqueous solution and the relevance of the MS method for binding studies be evaluated. A mobility shift ACE method was used for determining the binding between the small peptide GAPAGPLIVPY and various metal ions in aqueous solution. The findings were compared to the MS results and further explained using computational methods. While the MS data showed a strong alkaline earth ion binding, the ACE results showed nonsignificant binding. The proposed vacuum state complex also decomposed during a molecular dynamic simulation in aqueous solution. This study shows that the formed stable peptide-metal ion adducts in the gas phase by ESI-MS does not imply the existence of analogous adducts in the aqueous phase. Comparing peptide-metal ion interaction under the gaseous MS and aqueous ACE conditions showed huge difference in binding behavior.

  17. Production, Purification, and Characterization of ¹⁵N-Labeled DNA Repair Proteins as Internal Standards for Mass Spectrometric Measurements.

    Science.gov (United States)

    Reddy, Prasad T; Jaruga, Pawel; Nelson, Bryant C; Lowenthal, Mark S; Jemth, Ann-Sofie; Loseva, Olga; Coskun, Erdem; Helleday, Thomas; Dizdaroglu, Miral

    2016-01-01

    Oxidatively induced DNA damage is caused in living organisms by a variety of damaging agents, resulting in the formation of a multiplicity of lesions, which are mutagenic and cytotoxic. Unless repaired by DNA repair mechanisms before DNA replication, DNA lesions can lead to genomic instability, which is one of the hallmarks of cancer. Oxidatively induced DNA damage is mainly repaired by base excision repair pathway with the involvement of a plethora of proteins. Cancer tissues develop greater DNA repair capacity than normal tissues by overexpressing DNA repair proteins. Increased DNA repair in tumors that removes DNA lesions generated by therapeutic agents before they became toxic is a major mechanism in the development of therapy resistance. Evidence suggests that DNA repair capacity may be a predictive biomarker of patient response. Thus, knowledge of DNA-protein expressions in disease-free and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. Our laboratory has developed methodologies that use mass spectrometry with isotope dilution for the measurement of expression of DNA repair proteins in human tissues and cultured cells. For this purpose, full-length (15)N-labeled analogs of a number of human DNA repair proteins have been produced and purified to be used as internal standards for positive identification and accurate quantification. This chapter describes in detail the protocols of this work. The use of (15)N-labeled proteins as internal standards for the measurement of several DNA repair proteins in vivo is also presented.

  18. Mass spectrometric determination of partial electron impact ionization cross sections of No, No2, and N2O from threshold up to 180 eV

    International Nuclear Information System (INIS)

    Electron impact ionization of nitric oxide (NO), nitrogen dioxide (NO2) and nitrous oxide (N2O) has been studied as a function of electron energy up to 180 eV with a double focussing mass spectrometer Varian MAT CH5 and an improved Nier type electron impact ion source. Relative partial ionization cross sections were measured for the processes NO+ + 2e, NO++ + 3e, and NO2 + e -> NO+2 + 2e, NO++ + 3e and N2O + e -> N2O+ + 2e. An accurate measurement of the cross section ratios q(NO2+/NO)/q(NO+/NO) and q(NO22/NO2)/q(NO+2/NO2) has been made. Relative cross section functions were calibrated absolutely with two different normalization methods. Moreover, both metastable and collision induced dissociations of N2O+ were studied quantitatively using the technique of decoupling the acceleration and deflection electric fields. Using the n- th root extrapolation the following ionization potentials have been derived from the cross section functions near threshold: NO+(X1Σ+); NO++; NO+2; NO2++; N2O+(X2π). These results are compared with previous measurements and theoretical calculations, where available. Part of the results presented have been already published in seven papers by the author. (Author)

  19. Gas chromatography-mass spectrometric determination of polycyclic aromatic hydrocarbons in five species of fish from three sites in the Arabian Gulf.

    Science.gov (United States)

    Al-Saleh, Iman; Al-Doush, Inaam

    2002-06-01

    A gas chromatography-mass spectrmetroic (GC-MS) method was developed to measure six polycyclic aromatic hydrocarbons (PAHs) in 54 fish samples. Five fish species highly consumed by the local population (shrimps, Emperors, Rabbitfish, Doublebar Bream and Greasy Grouper) were selected from three different sites on the Gulf coast of Saudi Arabia where agricultural, municipal and petroleum industry activities take place. Variations in PAH levels among the three sites were not significant. Total concentrations of PAHs benzo(a)anthracene, chrysene, and benzo(b)fluoranthene ranged from non-detectable to 44.9 microg kg(-1). In this study, concentrations of benzo(a)anthracene, chrysene, benzo(b)fluoranthene and total PAHs greater than the acceptable tolerance limit (1 microg kg(-1)) were found in 68.5, 40.7, 51.9 and 83.3% of the fish samples, respectively. PAH contents in fish vary considerably with species; Doublebar bream contain the highest while shrimps contain the lowest. This pilot study clearly shows that the consumption of fish could be a source of exposure of the local population to PAHs. Since there is a consensus on the substantial contribution of PAHs to cancer in humans, it would be interesting to conduct further research in order to determine the magnitude of the problem along other coastal regions of Saudi Arabia.

  20. QuEChERS Method Followed by Solid Phase Extraction Method for Gas Chromatographic-Mass Spectrometric Determination of Polycyclic Aromatic Hydrocarbons in Fish

    Directory of Open Access Journals (Sweden)

    Mona Khorshid

    2015-01-01

    Full Text Available A gas chromatography equipped with mass spectrometer (GCMS method was developed and validated for determination of 16 polycyclic aromatic hydrocarbons (PAHs in fish using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS method for extraction and solid phase extraction for sample cleanup to remove most of the coextract combined with GCMS for determination of low concentration of selected group of PAHs in homogenized fish samples. PAHs were separated on a GCMS with HP-5ms Ultra Inert GC Column (30 m, 0.25 mm, and 0.25 µm. Mean recovery ranged from 56 to 115%. The extraction efficiency was consistent over the entire range where indeno(1,2,3-cdpyrene and benzo(g,h,iperylene showed recovery (65, 69%, respectively, at 2 µg/kg. No significant dispersion of results was observed for the other remaining PAHs and recovery did not differ substantially, and at the lowest and the highest concentrations mean recovery and RSD% showed that most of PAHs were between 70% and 120% with RSD less than 10%. The measurement uncertainty is expressed as expanded uncertainty and in terms of relative standard deviation (at 95% confidence level is ±12%. This method is suitable for laboratories engaged daily in routine analysis of a large number of samples.

  1. Fabrication of SO/sub 2/preparation system and calibration of PINSTECH sulfur standard for /sup 34/S/sup 32/S mass spectrometric analysis

    International Nuclear Information System (INIS)

    This report describes the fabrication and standardization of operation procedures of a SO/sub 2/ preparation system used for the extraction of sulfur dioxide gas from sulfur minerals (aqueous sulfate, elemental sulfur, and sulfides) for sulfur isotope ratio measurements on a gas source mass spectrometer for hydrological, geological and environmental applications. SO/sub 2/ preparation procedure as described by Fumitaka Yanagisawa and Hitoshi Sakai (1983) is adopted with some modifications. A chemically pure BaSO/sub 4/ powder is chosen as PINSTECH Sulfur Standard PSS-I for routine laboratory /sup 34/S analysis. PSS-1 is calibrated against the International Atomic Energy Agency (IAEA) standard Cannon Diablo Troilite (CDT) using the NBS-127 sulfur standard Sigma /sup 34/S values of PSS-1 as analyzed at PINSTECH and Institute fur Hydorlogie, Munich are found to be 14.58 +-0.07 % CDT (n=6) and 14.59+-0.15% CDT (n=2) respectively. NBS-127 is BaSO/sub 4/ powder from the National Bureau of Standards, USA and has been calibrated against CDT. Interlaboratory comparison of various standards is also documented. Using this system, the reproducibility of sulfur isotope ratio measurements is better than +-0.2 % (n=10). (author)

  2. Mass spectrometric evaluation of mephedrone in vivo human metabolism: identification of phase I and phase II metabolites, including a novel succinyl conjugate.

    Science.gov (United States)

    Pozo, Óscar J; Ibáñez, María; Sancho, Juan V; Lahoz-Beneytez, Julio; Farré, Magí; Papaseit, Esther; de la Torre, Rafael; Hernández, Félix

    2015-02-01

    In recent years, many new designer drugs have emerged, including the group of cathinone derivatives. One frequently occurring drug is mephedrone; although mephedrone was originally considered as a "legal high" product, it is currently banned in most Western countries. Despite the banning, abuse of the drug and seizures are continuously reported. Although the metabolism of mephedrone has been studied in rats or in vitro using human liver microsomes, to the best of our knowledge, no dedicated study with human volunteers has been performed for studying the in vivo metabolism of mephedrone in humans. Therefore, the aim of this study was to establish the actual human metabolism of mephedrone and to compare it with other models. For this purpose, urine samples of two healthy volunteers, who ingested 200 mg mephedrone orally, were taken before administration and 4 hours after substance intake. The discovery and identification of the phase I and phase II metabolites of mephedrone were based on ultra-high-performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry, operating in the so-called MS(E) mode. Six phase I metabolites and four phase II metabolites were identified, four of them not previously reported in the literature. The structure of four of the detected metabolites was confirmed by synthesis of the suggested compounds. Remarkably, a mephedrone metabolite conjugated with succinic acid has been identified and confirmed by synthesis. According to the reviewed literature, this is the first time that this type of conjugate is reported for human metabolism.

  3. Comparative Label-Free Mass Spectrometric Analysis of Mildly versus Severely Affected mdx Mouse Skeletal Muscles Identifies Annexin, Lamin, and Vimentin as Universal Dystrophic Markers

    Directory of Open Access Journals (Sweden)

    Ashling Holland

    2015-06-01

    Full Text Available The primary deficiency in the membrane cytoskeletal protein dystrophin results in complex changes in dystrophic muscles. In order to compare the degree of secondary alterations in differently affected subtypes of skeletal muscles, we have conducted a global analysis of proteome-wide changes in various dystrophin-deficient muscles. In contrast to the highly degenerative mdx diaphragm muscle, which showed considerable alterations in 35 distinct proteins, the spectrum of mildly to moderately dystrophic skeletal muscles, including interosseus, flexor digitorum brevis, soleus, and extensor digitorum longus muscle, exhibited a smaller number of changed proteins. Compensatory mechanisms and/or cellular variances may be responsible for differing secondary changes in individual mdx muscles. Label-free mass spectrometry established altered expression levels for diaphragm proteins associated with contraction, energy metabolism, the cytoskeleton, the extracellular matrix and the cellular stress response. Comparative immunoblotting verified the differences in the degree of secondary changes in dystrophin-deficient muscles and showed that the up-regulation of molecular chaperones, the compensatory increase in proteins of the intermediate filaments, the fibrosis-related increase in collagen levels and the pathophysiological decrease in calcium binding proteins is more pronounced in mdx diaphragm as compared to the less severely affected mdx leg muscles. Annexin, lamin, and vimentin were identified as universal dystrophic markers.

  4. Mass spectrometric analysis of neutral and anionic N-glycans from a Dictyostelium discoideum model for human congenital disorder of glycosylation CDG IL.

    Science.gov (United States)

    Hykollari, Alba; Balog, Crina I A; Rendić, Dubravko; Braulke, Thomas; Wilson, Iain B H; Paschinger, Katharina

    2013-03-01

    The HL241 mutant strain of the cellular slime mold Dictyostelium discoideum is a potential model for human congenital disorder of glycosylation type IL (ALG9-CDG) and has been previously predicted to possess a lower degree of modification of its N-glycans with anionic moieties than the parental wild-type. In this study, we first showed that this strain has a premature stop codon in its alg9 mannosyltransferase gene compatible with the occurrence of truncated N-glycans. These were subject to an optimized analytical workflow, considering that the mass spectrometry of acidic glycans often presents challenges due to neutral loss and suppression effects. Therefore, the protein-bound N-glycans were first fractionated, after serial enzymatic release, by solid phase extraction. Then primarily single glycan species were isolated by mixed hydrophilic-interaction/anion-exchange or reversed-phase HPLC and analyzed using chemical and enzymatic treatments and MS/MS. We show that protein-linked N-glycans of the mutant are of reduced size as compared to those of wild-type AX3, but still contain core α1,3-fucose, intersecting N-acetylglucosamine, bisecting N-acetylglucosamine, methylphosphate, phosphate, and sulfate residues. We observe that a single N-glycan can carry up to four of these six possible modifications. Due to the improved analytical procedures, we reveal fuller details regarding the N-glycomic potential of this fascinating model organism. PMID:23320427

  5. Validation of a liquid chromatography-electrospray ionization tandem mass spectrometric method to determine six polyether ionophores in raw, UHT, pasteurized and powdered milk.

    Science.gov (United States)

    Pereira, Mararlene Ulberg; Spisso, Bernardete Ferraz; Jacob, Silvana do Couto; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; Carlos, Betânia de Souza; da Nóbrega, Armi Wanderley

    2016-04-01

    This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. PMID:26593474

  6. N-Alkylpyridinium isotope quaternization for matrix-assisted laser desorption/ionization Fourier transform mass spectrometric analysis of cholesterol and fatty alcohols in human hair

    International Nuclear Information System (INIS)

    Isotope-coded reagents have been developed for labeling of amino acids, phenols and fatty acids, but not for alcohols. In this work, a simple reaction based on direct N-alkylpyridinium isotope quaternization (NAPIQ) was developed for mild derivatization of cholesterol and fatty alcohols. Different from the conventional quaternary reagents with cations on themselves, two simple and charge-neutral reagents: pyridine and d5-pyridine directly attached N-cationic tag onto the target compounds in the presence of trifluoromethanesulfonic anhydride (Tf2O) without tedious sample preparation. The derivatization completed in 5 min and achieved charge labeling of the target compounds, which significantly improved the detection limits of analytes by 103-folds in further analysis by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). The use of commercially available d0/d5-pyridine pairs facilitated isotope-coded chemical derivatization and avoided the use of isotope-labeled internal standards; the excess pyridine did not affect the signals of analytes. Utility of the NAPIQ method was examined in the identification of cholesterol and fatty alcohols in small amount of human hair sample (0/d5 pairs, especially when isotope-labeled internal standards are unavailable.

  7. A rapid gas chromatographic injection-port derivatization method for the tandem mass spectrometric determination of patulin and 5-hydroxymethylfurfural in fruit juices.

    Science.gov (United States)

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2016-07-01

    A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6μg/kg and LOQ of 2 and 5μg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000μg/kg and between 5 and 192μg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples. PMID:27240947

  8. Mass Spectrometric Imaging of Wheat (Triticum spp.) and Barley (Hordeum vulgare L.) Cultivars: Distribution of Major Cell Wall Polysaccharides According to Their Main Structural Features.

    Science.gov (United States)

    Veličković, Dušan; Saulnier, Luc; Lhomme, Margot; Damond, Aurélie; Guillon, Fabienne; Rogniaux, Hélène

    2016-08-17

    Arabinoxylans (AX) and (1→3),(1→4)-β-glucans (BG) are the main components of cereal cell walls and influence many aspects of their end uses. Important variations in the composition and structure of these polysaccharides have been reported among cereals and cultivars of a given species. In this work, the spatial distribution of AX and BG in the endosperm of mature grains was established for nine wheat varieties and eight barley varieties using enzymatically assisted mass spectrometry imaging (MSI). Important structural features of the AX and BG polymers that were previously shown to influence their physicochemical properties were assessed. Differences in the distribution of AX and BG structures were observed, both within the endosperm of a given cultivar and between wheat and barley cultivars. This study provides a unique picture of the structural heterogeneity of AX and BG polysaccharides at the scale of the whole endosperm in a series of wheat and barley cultivars. Thus, it can participate meaningfully in a strategy aiming at understanding the structure-function relationships of these two polymers. PMID:27463368

  9. Performance evaluation of a thermal desorption/gas chromatographic/mass spectrometric method for the characterization of waste tank headspace samples

    International Nuclear Information System (INIS)

    A thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) method was validated for the determination of volatile organic compounds collected on carbonaceous triple sorbent traps and applied to characterize samples of headspace gases collected from underground nuclear waste storage tanks at the U.S. Department of Energy's Hanford site, in Richland, WA. Method validation used vapor-phase standards generated from 25 target analytes, including alkanes, alkyl alcohols, alkyl ketones, alkylated aromatics, and alkyl nitriles. The target analytes represent a group of compounds identified in one of the most problematic tanks. TD/GC/MS was carried out with modified injectors. Performance was characterized based on desorption efficiency, reproducibility, stability, and linearity of the calibration, method detection limits, preanalytical holding time, and quality control limits for surrogate standard recoveries. Desorption efficiencies were all greater than 82%, and the majority of the analytes (23 out of 25) had reproducibility values less than 24% near the method detection levels. The method was applied to the analysis of a total of 305 samples collected from the headspaces of 48 underground waste storge tanks. Quality control procedures were implemented to monitor sampling and TD/GC/MS method. 33 refs., 2 figs., 4 tabs

  10. Solid phase extraction and preconcentration of uranium(VI) and thorium(IV) on Duolite XAD761 prior to their inductively coupled plasma mass spectrometric determination.

    Science.gov (United States)

    Aydin, Funda Armagan; Soylak, Mustafa

    2007-04-15

    A simple and effective method is presented for the separation and preconcentration of thorium(IV) and uranium(VI) by solid phase extraction on Duolite XAD761 adsorption resin. Thorium(IV) and uranium(VI) 9-phenyl-3-fluorone chelates are formed and adsorbed onto the Duolite XAD761. Thorium(IV) and uranium(VI) are quantitatively eluted with 2molL(-1) HCl and determined by inductively coupled plasma-mass spectrometry (ICP-MS). The influences of analytical parameters including pH, amount of reagents, amount of Duolite XAD761 and sample volume, etc. were investigated on the recovery of analyte ions. The interference of a large number of anions and cations has been studied and the optimized conditions developed have been utilized for the trace determination of uranium and thorium. A preconcentration factor of 30 for uranium and thorium was achieved. The relative standard deviation (N=10) was 2.3% for uranium and 4.5% for thorium ions for 10 replicate determinations in the solution containing 0.5mug of uranium and thorium. The three sigma detection limits (N=15) for thorium(IV) and uranium(VI) ions were found to be 4.5 and 6.3ngL(-1), respectively. The developed solid phase extraction method was successively utilized for the determination of traces thorium(IV) and uranium(VI) in environmental samples by ICP-MS. PMID:19071600

  11. Mass Spectrometric Analysis of Glyoxal and Methylglyoxal-Induced Modifications in Human Hemoglobin from Poorly Controlled Type 2 Diabetes Mellitus Patients.

    Science.gov (United States)

    Chen, Hauh-Jyun Candy; Chen, Yu-Chin; Hsiao, Chiung-Fong; Chen, Pin-Fan

    2015-12-21

    Glyoxal and methylglyoxal are oxoaldehydes derived from the degradation of glucose-protein conjugates and from lipid peroxidation, and they are also present in the environment. This study investigated the site-specific reaction of glyoxal and methylglyoxal with the amino acid residues on human hemoglobin using a shot-gun proteomic approach with nanoflow liquid chromatography/nanospray ionization tandem mass spectrometry (nanoLC-NSI/MS/MS). In human hemoglobin incubated with glyoxal, modification on 8 different sites, including lysine residues at α-Lys-11, α-Lys-16, α-Lys-56, β-Lys-17, β-Lys-66, β-Lys-144, and arginine residues at α-Arg-92 and β-Arg-30, was observed using a data-dependent scan. In methylglyoxal-treated hemoglobin, there were specific residues, namely, α-Arg-92, β-Lys-66, β-Arg-30, and β-Lys-144, forming carboxyethylation as well as the dehydrated product hydroimidazolone at α-Arg-92 and β-Arg-30. These lysine and arginine modifications were confirmed by accurate mass measurement and the MS(2) and MS(3) spectra. The most intensive signal of each modified peptide was used as the precursor ion to perform the product ion scan. The relative extent of modifications was semiquantified simultaneously relative to the native reference peptide by nanoLC-NSI/MS/MS under the selected reaction monitoring (SRM) mode. The extent of these modifications increased dose-dependently with increasing concentrations of glyoxal or methylglyoxal. Six out of the eight modifications induced by glyoxal and three out of the six modifications induced by methylglyoxal were detected in hemoglobin freshly isolated from human blood samples. The relative extent of modification of these post-translational modifications was quantified in poorly controlled type 2 diabetes mellitus patients (n = 20) and in nondiabetic control subjects (n = 21). The results show that the carboxymethylated peptides at α-Lys-16, α-Arg-92, β-Lys-17, β-Lys-66, and the peptide at α-Arg-92

  12. Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Akihiro [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nishida, Manami [Hiroshima University Technical Center, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Saito, Takeshi [Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1143 (Japan); Kishiyama, Izumi; Miyazaki, Shota [GL Sciences Inc., Sayamagahara 237-2, Iruma, Saitama 358-0032 (Japan); Murakami, Katsunori [Scientific Investigation Laboratory, Hiroshima Prefectural Police Headquarters, Kohnan 2-26-3, Naka-ku, Hiroshima 730-0825 (Japan); Nagao, Masataka [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan); Namura, Akira, E-mail: namera@hiroshima-u.ac.jp [Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551 (Japan)

    2010-02-19

    A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d{sub 5} was used as an internal standard. The linear ranges were 0.01-5.0 {mu}g mL{sup -1} for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 {mu}g mL{sup -1} for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation {>=}0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 {mu}g mL{sup -1} of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio {>=} 3) in urine was 5 ng mL{sup -1} for MA and MDMA and 10 ng mL{sup -1} for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation.

  13. Gas chromatography coupled with mass spectrometric characterization of Curcuma longa: Protection against pathogenic microbes and lipid peroxidation in rat's tissue homogenate.

    Science.gov (United States)

    Hassan, Waseem; Gul, Shehnaz; Rehman, Shakilla; Kanwal, Farina; Afridi, Muhammad Siddique; Fazal, Hina; Shah, Ziarat; Rahman, Ataur; da Rocha, Joao B T

    2016-03-01

    The present study was designed to investigate the mineral content and antimicrobial activity of Curcuma Longa extracts and its essential oil. We also determined the lipid peroxidation inhibition activity of the ethanolic extract against sodium nitroprusside (SNP) induced thiobarbituric acid reactive species (TBARS) formation in rat's brain, kidney and liver homogenates. Major constituents of essential oil identified by gas chromatography and mass spectrometry (GCMS) were beta-sesquiphellandrene (38.69%), alpha-curcumene (18.44%) and p-mentha-1,4 (8)-diene (16.29%). Atomic absorption spectroscopy (AAS) was used for the quantitative estimation of Calcium (Ca), Magnesium (Mg), Iron (Fe), Copper (Cu), Zinc (Zn), Chromium (Cr), Nickel (Ni) and Manganese (Mn). The extract showed highest Mg (49.4 mg/l) concentration followed by Ca (35.42 mg/l) and Fe (1.27 mg/l). Our data revealed that the ethanolic extract of Curcuma Longa at 1-10 mg/kg significantly inhibited TBARS production in all tested homogenates. Crude extracts and essential oil were tested against three gram positive bacteria i.e. Bacillus subtilis, Bacillus atrophoeus, Staphylococcus aureus, six gram negative bacteria i.e. Escherichia coli, Klebsiella pneumonias, Salmonella typhi, Pseudomonas aeruginosa, Erwinia carotovora, Agrobacterium tumefaciens and one fungal strain namely Candida albicans by disc diffusion assay. Essential oil showed highest anti-microbial activity as compared to the crude extracts. The present study confirms the significant antimicrobial and antioxidant potential of the studied plant, which can be considered as a diet supplement for a variety of oxidative stress induced or infectious diseases.

  14. A mass spectrometric study of ions extracted from a point-to-plane dc corona discharge in N{sub 2}O at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Skalny, J D; Orszagh, J [Department of Plasma Physics, Comenius University, Mlynska dolina F-2, 84248 Bratislava (Slovakia); Mason, N J [Department of Physics and Astronomy, Centre of Molecular and Optical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Rees, J A; Aranda-Gonzalvo, Y; Whitmore, T D [Plasma and Surface Analysis Division, Hiden Analytical Ltd, 420 Europa Boulevard, Warrington WA5 7UN (United Kingdom)], E-mail: Skalny@fmph.uniba.sk

    2008-04-21

    In this paper we report the first study of ions formed in both positive and negative point-to-plane corona discharges fed by N{sub 2}O containing less than 0.1% of H{sub 2}O at atmospheric pressure. Considerable differences were observed in the mass spectra of the ions produced from corona discharges of different polarities. In all the discharges the product ions were observed mainly in the form of clusters. However, in positive corona discharges only four major groups of cluster ions were monitored whereas in all corona discharges operated with negative polarity a much more varied and complex variety of negative ions was observed. The spectrum of positive ions is highly sensitive to the content of water vapour in nitrous oxide with H{sub 3} O{sup +} {center_dot} (H{sub 2}O){sub n} clusters (especially H{sub 3}O{sup +} {center_dot} (H{sub 2}O){sub 3}) and NO{sup +} {center_dot} (H{sub 2}O){sub n} clusters being the dominant products. The yield of NO{sup +} {center_dot} (H{sub 2}O){sub n} was found to increase strongly with increasing discharge current while the yield of H{sub 3}O{sup +} {center_dot} (H{sub 2}O){sub n} clusters was reduced. Spectra of ions detected in negative corona discharges contain clusters of NO{sup -}, NO{sub 2}{sup -}, NO{sub 3}{sup -} ions and also HNO{sub 3}{sup -} clustered with N{sub 2}O, NO, NO{sub 2}, H{sub 2}O and HNO{sub 3}. This paper reports how the yield of such ions is influenced by the plasma characteristics and discusses how these results may be explained by physical and chemical processes in the plasma.

  15. A mass spectrometric study of ions extracted from a point-to-plane dc corona discharge in N2O at atmospheric pressure

    International Nuclear Information System (INIS)

    In this paper we report the first study of ions formed in both positive and negative point-to-plane corona discharges fed by N2O containing less than 0.1% of H2O at atmospheric pressure. Considerable differences were observed in the mass spectra of the ions produced from corona discharges of different polarities. In all the discharges the product ions were observed mainly in the form of clusters. However, in positive corona discharges only four major groups of cluster ions were monitored whereas in all corona discharges operated with negative polarity a much more varied and complex variety of negative ions was observed. The spectrum of positive ions is highly sensitive to the content of water vapour in nitrous oxide with H3 O+ · (H2O)n clusters (especially H3O+ · (H2O)3) and NO+ · (H2O)n clusters being the dominant products. The yield of NO+ · (H2O)n was found to increase strongly with increasing discharge current while the yield of H3O+ · (H2O)n clusters was reduced. Spectra of ions detected in negative corona discharges contain clusters of NO-, NO2-, NO3- ions and also HNO3- clustered with N2O, NO, NO2, H2O and HNO3. This paper reports how the yield of such ions is influenced by the plasma characteristics and discusses how these results may be explained by physical and chemical processes in the plasma

  16. Gas chromatography coupled with mass spectrometric characterization of Curcuma longa: Protection against pathogenic microbes and lipid peroxidation in rat's tissue homogenate.

    Science.gov (United States)

    Hassan, Waseem; Gul, Shehnaz; Rehman, Shakilla; Kanwal, Farina; Afridi, Muhammad Siddique; Fazal, Hina; Shah, Ziarat; Rahman, Ataur; da Rocha, Joao B T

    2016-03-01

    The present study was designed to investigate the mineral content and antimicrobial activity of Curcuma Longa extracts and its essential oil. We also determined the lipid peroxidation inhibition activity of the ethanolic extract against sodium nitroprusside (SNP) induced thiobarbituric acid reactive species (TBARS) formation in rat's brain, kidney and liver homogenates. Major constituents of essential oil identified by gas chromatography and mass spectrometry (GCMS) were beta-sesquiphellandrene (38.69%), alpha-curcumene (18.44%) and p-mentha-1,4 (8)-diene (16.29%). Atomic absorption spectroscopy (AAS) was used for the quantitative estimation of Calcium (Ca), Magnesium (Mg), Iron (Fe), Copper (Cu), Zinc (Zn), Chromium (Cr), Nickel (Ni) and Manganese (Mn). The extract showed highest Mg (49.4 mg/l) concentration followed by Ca (35.42 mg/l) and Fe (1.27 mg/l). Our data revealed that the ethanolic extract of Curcuma Longa at 1-10 mg/kg significantly inhibited TBARS production in all tested homogenates. Crude extracts and essential oil were tested against three gram positive bacteria i.e. Bacillus subtilis, Bacillus atrophoeus, Staphylococcus aureus, six gram negative bacteria i.e. Escherichia coli, Klebsiella pneumonias, Salmonella typhi, Pseudomonas aeruginosa, Erwinia carotovora, Agrobacterium tumefaciens and one fungal strain namely Candida albicans by disc diffusion assay. Essential oil showed highest anti-microbial activity as compared to the crude extracts. The present study confirms the significant antimicrobial and antioxidant potential of the studied plant, which can be considered as a diet supplement for a variety of oxidative stress induced or infectious diseases. PMID:27087084

  17. Mass spectrometric determination of O2 gas exchange during a dark-to-light transition in higher-plant cells : Evidence for two individual O2-uptake components.

    Science.gov (United States)

    Avelange, M H; Rébeillé, F

    1991-01-01

    The exchange of O2 and CO2 by photoautotrophic cells of Euphorbia characias L. was measured using a mass-spectrometry technique. During a dark-tolight transition the O2 uptake rate was little affected whereas CO2 efflux was decreased by 40%. In order to differentiate eventual superimposed O2-uptake processes, the kinetics of O2 exchange resulting from brief illuminations were measured with a highly sensitive device. When the cells were exposed to a saturating light for short periods, the rate of O2 uptake passed through a series of transients: there was first a stimulation occurring 2-3 s after the appearance of O2 from water-splitting, followed 30 s later by an inhibition. These two transients were reduced 80% by 3-(3',4'-dichlorophenyl)1, 1-dimethylurea (DCMU), indicating that they relied on the linear transport of electrons in the chloroplasts. The first transient (stimulation of an O2 uptake) was little affected by mitochondrial inhibitors such as antimycin A and oligomycin or the uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) but was increased in presence of KCN. When spaced flashes (2 us duration; 100-ms intervals) were used instead of continuous light, this transient was almost suppressed indicating that it was dependent on the saturation of some component of the chloroplastic chain. The second transient (inhibition of O2 uptake) was present when spaced flashes were used instead of continuous light. It was markedly decreased by addition of CCCP and mitochondrial inhibitors (antimycin A, oligomycin, KCN) which strongly indicates that it relied on mitochondrial respiration. It is concluded from these experiments that illumination of the cells resulted in an inhibition of mitochondrial respiration, but the resulting inhibition of O2 uptake was hidden by the appearance of an O2-uptake process of extramitochondrial origin, presumably located in the chloroplast. PMID:24193615

  18. Mass-spectrometric determination of O2 and CO 2 gas exchange in illuminated higher-plant cells : Evidence for light-inhibition of substrate decarboxylations.

    Science.gov (United States)

    Avelange, M H; Thiéry, J M; Sarrey, F; Gans, P; Rébeillé, F

    1991-01-01

    In order to estimate photosynthetic and respiratory rates in illuminated photoautotrophic cells of carnation (Dianthus caryophyllus L.), simultaneous measurements of CO2 and O2 gas exchange were performed using (18)O2, (13)CO2 and a mass-spectrometry technique. This method allowed the determination, and thus the comparison, of unidirectional fluxes of O2 and CO2. In optimum photosynthetic conditions (i.e. in the presence of high light and a saturating level of CO2), the rate of CO2 influx represented 75±5% of the rate of gross O2 evolution. After a dark-to-light transition, the rate of CO2 efflux was inhibited by 50% whereas the O2-uptake rate was little affected. The effect of a recycling of respiratory CO2 through photosynthesis on the exchange of CO2 gas was investigated using a mathematical model. The confliction of the experimental data with the simulated gas-exchange rates strongly supported the view that CO2 recycling was a minor event in these cells and could not be responsible for the observed inhibition of CO2 efflux. On the basis of this assumption it was concluded that illumination of carnation cells resulted in a decrease of substrate decarboxylations, and that CO2 efflux and O2 uptake were not as tightly coupled in the light as in the dark. Furthermore, it could be calculated from the rate of gross photosynthesis that the chloroplastic electron-transport chain produced enough ATP in the light to account for the measured CO2-uptake rate without involving cyclic transfer of electrons around PS I or mitochondrial supplementation. PMID:24193614

  19. Aerosol mass spectrometric analysis of the chemical composition of non-refractory PM(1) samples from school environments in Brisbane, Australia.

    Science.gov (United States)

    Crilley, Leigh R; Ayoko, Godwin A; Jayaratne, E Rohan; Salimi, Farhad; Morawska, Lidia

    2013-08-01

    Long-term exposure to vehicle emissions has been associated with detrimental health effects. Children are amongst the most susceptible group and schools represent an environment where they can experience significant exposure to vehicle emissions. However, there are limited studies on children's exposure to vehicle emissions in schools. The aim of this study was to quantify the concentration of organic aerosol (OA) and in particular, vehicle emissions that children are exposed to during school hours. Therefore an Aerodyne compact time-of-flight aerosol mass spectrometer (TOF-AMS) was deployed at five urban schools in Brisbane, Australia. TOF-AMS enabled the chemical composition of the non-refractory (NR-PM1) to be analysed with a high temporal resolution to assess the concentration of vehicle emissions and other OA components during school hours. The organic fraction at each school comprised the majority of NR-PM1. Primary emissions were found to dominate the OA at only one school which had an O:C ratio of 0.17, due to fuel powered gardening equipment used near the TOF-AMS. A significant source of the OA at two of the schools was aged vehicle emissions from nearby highways. More oxidised OA was observed at the remaining two schools, which also recorded strong biomass burning influences. In general, the diurnal cycle of the total OA concentration varied between schools and was found to be at a minimum during school hours. The major organic component that school children were exposed to during school hours was secondary OA at all schools. Peak exposure of school children to vehicle emissions occurred during school drop-off and pick-up times. Unless a school is located near major roads, children are exposed predominately to regional secondary OA as opposed to local emissions during school hours in urban environments. PMID:23644356

  20. A comparative study on the analytical utility of atmospheric and low-pressure MALDI sources for the mass spectrometric characterization of peptides.

    Science.gov (United States)

    Moskovets, Eugene; Misharin, Alexander; Laiko, Viktor; Doroshenko, Vladimir

    2016-07-15

    A comparative MS study was conducted on the analytical performance of two matrix-assisted laser desorption/ionization (MALDI) sources that operated at either low pressure (∼1Torr) or at atmospheric pressure. In both cases, the MALDI sources were attached to a linear ion trap mass spectrometer equipped with a two-stage ion funnel. The obtained results indicate that the limits of detection, in the analysis of identical peptide samples, were much lower with the source that was operated slightly below the 1-Torr pressure. In the low-pressure (LP) MALDI source, ion signals were observed at a laser fluence that was considerably lower than the one determining the appearance of ion signals in the atmospheric pressure (AP) MALDI source. When the near-threshold laser fluences were used to record MALDI MS spectra at 1-Torr and 750-Torr pressures, the level of chemical noise at the 1-Torr pressure was much lower compared to that at AP. The dependency of the analyte ion signals on the accelerating field which dragged the ions from the MALDI plate to the MS analyzer are presented for the LP and AP MALDI sources. The study indicates that the laser fluence, background gas pressure, and field accelerating the ions away from a MALDI plate were the main parameters which determined the ion yield, signal-to-noise (S/N) ratios, the fragmentation of the analyte ions, and adduct formation in the LP and AP MALDI MS methods. The presented results can be helpful for a deeper insight into the mechanisms responsible for the ion formation in MALDI.

  1. A comparative study on the analytical utility of atmospheric and low-pressure MALDI sources for the mass spectrometric characterization of peptides.

    Science.gov (United States)

    Moskovets, Eugene; Misharin, Alexander; Laiko, Viktor; Doroshenko, Vladimir

    2016-07-15

    A comparative MS study was conducted on the analytical performance of two matrix-assisted laser desorption/ionization (MALDI) sources that operated at either low pressure (∼1Torr) or at atmospheric pressure. In both cases, the MALDI sources were attached to a linear ion trap mass spectrometer equipped with a two-stage ion funnel. The obtained results indicate that the limits of detection, in the analysis of identical peptide samples, were much lower with the source that was operated slightly below the 1-Torr pressure. In the low-pressure (LP) MALDI source, ion signals were observed at a laser fluence that was considerably lower than the one determining the appearance of ion signals in the atmospheric pressure (AP) MALDI source. When the near-threshold laser fluences were used to record MALDI MS spectra at 1-Torr and 750-Torr pressures, the level of chemical noise at the 1-Torr pressure was much lower compared to that at AP. The dependency of the analyte ion signals on the accelerating field which dragged the ions from the MALDI plate to the MS analyzer are presented for the LP and AP MALDI sources. The study indicates that the laser fluence, background gas pressure, and field accelerating the ions away from a MALDI plate were the main parameters which determined the ion yield, signal-to-noise (S/N) ratios, the fragmentation of the analyte ions, and adduct formation in the LP and AP MALDI MS methods. The presented results can be helpful for a deeper insight into the mechanisms responsible for the ion formation in MALDI. PMID:26899429

  2. N-Alkylpyridinium isotope quaternization for matrix-assisted laser desorption/ionization Fourier transform mass spectrometric analysis of cholesterol and fatty alcohols in human hair

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hang; Wang Haoyang; Zhang Li; Zhang Jing [Shanghai Mass Spectrometry Center, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China); Guo Yinlong, E-mail: ylguo@sioc.ac.cn [Shanghai Mass Spectrometry Center, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China)

    2011-03-25

    Isotope-coded reagents have been developed for labeling of amino acids, phenols and fatty acids, but not for alcohols. In this work, a simple reaction based on direct N-alkylpyridinium isotope quaternization (NAPIQ) was developed for mild derivatization of cholesterol and fatty alcohols. Different from the conventional quaternary reagents with cations on themselves, two simple and charge-neutral reagents: pyridine and d{sub 5}-pyridine directly attached N-cationic tag onto the target compounds in the presence of trifluoromethanesulfonic anhydride (Tf{sub 2}O) without tedious sample preparation. The derivatization completed in 5 min and achieved charge labeling of the target compounds, which significantly improved the detection limits of analytes by 10{sup 3}-folds in further analysis by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). The use of commercially available d{sub 0}/d{sub 5}-pyridine pairs facilitated isotope-coded chemical derivatization and avoided the use of isotope-labeled internal standards; the excess pyridine did not affect the signals of analytes. Utility of the NAPIQ method was examined in the identification of cholesterol and fatty alcohols in small amount of human hair sample (<0.5 mg). The fluctuation of total cholesterol in human body was profiled during time by quantitatively comparing the different segments of a single strand of hair. This study combines the direct pyridinium quaternization with MALDI-FTMS, which offers a perspective and an alternative tool for the identification and quantification of substances in biological matrix by comparing d{sub 0}/d{sub 5} pairs, especially when isotope-labeled internal standards are unavailable.

  3. Quantitative determination of the enantiomers of methadone in human plasma and saliva by chiral column chromatography coupled with mass spectrometric detection.

    Science.gov (United States)

    George, Rani; Lobb, Michael; Haywood, Alison; Khan, Sohil; Hardy, Janet; Good, Phillip; Hennig, Stefanie; Norris, Ross

    2016-01-01

    Methadone is a potent lipophilic synthetic opioid that is effective in the treatment of cancer pain and perceived benefit in difficult pain control scenarios (especially in cases of neuropathic pain). The use of methadone in clinical practice is challenging however, due to the narrow therapeutic window and large inter- and intra-individual variability in therapeutic response. Quantitation of the enantiomers d- and l-methadone (d- and l-MTD) in plasma and saliva provides a basis for studying its pharmacokinetics in patients with cancer and for monitoring efficacy, toxicity and side-effects. This assay involves quantitation of the enantiomers of methadone using their respective deuterated internal standards, in plasma and saliva matrices with no impact of ion suppression in either matrix. The analytical recoveries of d- and l-MTD from the saliva collection devices (Salivette®) are optimised in this novel method with an accurate and simple extraction method employing dichloromethane. Optimal enantioselective separations were achieved using an α1-acid glycoprotein chiral stationary phase and triple quadrupole tandem mass spectrometer. Linearity was demonstrated over 0.05-1000µg/L for both enantiomers in plasma and in saliva with correlation coefficients greater than 0.998. The lower limit of quantitation (LLOQ) was determined to be 0.1µg/L in plasma and saliva for d- and l-MTD. Accuracy of the method ranges from 100% to 106% even at the LLOQ and total precision, expressed as the coefficient of variation, was between 0.2% and 4.4% for both analytes in both matrices. A simple one step extraction procedure resulted in recoveries greater than 95% for both analytes, at concentrations as low as 0.5µg/L, from the Salivette®. The validated method was applied successfully in 14 paired plasma and saliva samples obtained from adult patients with cancer pain receiving methadone.

  4. Application of operationally defined speciation techniques to the inductively coupled plasma mass spectrometric analysis of trace and ultra-trace elements in soils

    International Nuclear Information System (INIS)

    The extractants examined in this study were an acid oxalate solution (Tamm's Reagent), a dithionite-citrate (DC) solution, and a pyrophosphate solution used for the extraction of trace and ultra-trace elements associated with amorphous Fe (Mn) oxide, crystalline Fe(Mn) oxide, and organic matter, respectively. Water and 1 M NH4NO3 were also examined for water soluble and exchangeable form, respectively. Water extracts were directly aspirated into an inductively coupled plasma mass spectrometer (ICP-MS) after a thorough removal of particulate materials. The NH4NO3 extracts were treated with aqua regia (HNO3 - HCl) to remove NH4NO3 before the ICP-MS analysis. The acid oxalate and pyrophosphate extracts were treated with HNO3 - HClO4 - HF to decompose the organic matter and also to remove Si. For dithionite-citrate extracts, however, HNO3 - H2SO4 decomposition process was applied rather than an HNO3 - HClO4 - HF treatment. This is because the extracts still contain a large amount of un-reacted dithionite, which prevents the successful application of the latter procedure. The residues obtained by the above procedures were all dissolved with HNO3. The solution thus prepared was finally passed through a column filled with an ion exchange resin that has chelating ability (Muromac A-1) with the addition of malonic acid. The whole procedure was optimized for separating the analytes from the major constituents (Na, Al, Fe, SO4, and PO4) by adjusting the pH of the solution, the amount of resin, the concentration of malonic acid, and the flow rate. Under optimum conditions, it was possible to separate around 20 trace and ultra-trace elements with acceptable recoveries. (author)

  5. Determination of total lead in lipstick: development and validation of a microwave-assisted digestion, inductively coupled plasma-mass spectrometric method.

    Science.gov (United States)

    Hepp, Nancy M; Mindak, William R; Cheng, John

    2009-01-01

    Recent reports describing the presence of lead (Pb) in lipsticks have suggested that, under ordinary use, the potential amount of Pb exposure is harmful. To permit independent assessment of the Pb contamination, a method for determining total Pb in lipstick using microwave-assisted digestion and analysis employing inductively coupled plasma-mass spectrometry (ICP-MS) was developed and validated. Since lipsticks may contain fats, oils, pigments, dyes, and minerals, several reference materials (RM) were analyzed, including coal, wear metals in oil, organic Pb in oil, milk powder, and estuarine sediment. With the exception of the RM with mineral content (estuarine sediment), complete recovery of Pb from the RMs was obtained by simple nitric acid (HNO(3)) digestion. Complete recovery of Pb from estuarine sediment was achieved only when hydrofluoric acid (HF) was added to the digestion mix, followed by treatment with excess boric acid (H(3)BO(3)) to neutralize the HF and to dissolve insoluble fluorides. Commercial lipsticks were tested for total Pb by the validated method. The detection limit was estimated to be 0.04 microg Pb/g. The average value obtained for the lipsticks was 1.07 microg/g. Undigested material was present in some lipstick digests when only HNO(3) was used, and generally lower Pb values were obtained. All of the Pb levels found by the U.S. Food and Drug Administration (FDA) were within the range the agency would expect to find in lipsticks formulated with permitted color additives and other ingredients prepared under good manufacturing practice (GMP) conditions. This method will be useful for the FDA and industry in helping to ensure the safety of cosmetic products. PMID:19691936

  6. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator S-22 to identify potential targets for routine doping controls.

    Science.gov (United States)

    Thevis, Mario; Thomas, Andreas; Möller, Ines; Geyer, Hans; Dalton, James T; Schänzer, Wilhelm

    2011-08-15

    Drugs that promote anabolic processes with limited undesirable effects are of considerable therapeutic interest; some notable examples include those for the treatment of cancer cachexia and muscle-wasting diseases. Anabolic properties are not only therapeutically beneficial to critically ill and debilitated patients, but are also desirable to athletes seeking artificial enhancements in endurance, strength and accelerated recovery. The use of anabolic agents in the clinical setting is being reconsidered with the emergence of a new class of drugs referred to as SARMs (selective androgen receptor modulators). SARMs have the potential to complement or even replace anabolic androgenic steroidal use with the benefit of a reduction of the undesirable side effects associated with steroid administration alone. Arylpropionamide-based SARMs such as andarine (S-4) and S-22 have shown promising therapeutic properties and have attracted the interest of elite and amateur athletes despite the absence of clinical approval, and evidence for trafficking and misuse in sport has been obtained by doping control authorities. In this communication, the elucidation of urinary metabolites of the SARM drug candidate S-22 is compared with earlier in vitro metabolism studies. Following oral administration of illicit S-22, urine samples were collected after 62 and 135 h and analyzed for the active drug and its major metabolic products. Liquid chromatography interfaced with high-resolution/high-accuracy (tandem) mass spectrometry was used to identify and/or confirm the predicted target analytes for sports drug testing purposes. S-22 was detected in both specimens accompanied by its glucuronic acid conjugate. This was the B-ring hydroxylated derivative of S-22 plus the corresponding glucuronide (with the phase-II metabolites being the more abundant analytes). In addition, the samples collected 62 h post-administration also contained the phase-I metabolite hydroxylated at the methyl residue (C-20

  7. Studies of organohalogen contamination of fish using neutron activation liquid chromatography, nuclear magnetic resonance and mass spectrometric techniques. Highlights and achievements

    International Nuclear Information System (INIS)

    ), NMR, and various types of mass spectrometry methods for the separation and identification of at least a couple of new EOCl compounds in cod ovaries

  8. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator S-22 to identify potential targets for routine doping controls.

    Science.gov (United States)

    Thevis, Mario; Thomas, Andreas; Möller, Ines; Geyer, Hans; Dalton, James T; Schänzer, Wilhelm

    2011-08-15

    Drugs that promote anabolic processes with limited undesirable effects are of considerable therapeutic interest; some notable examples include those for the treatment of cancer cachexia and muscle-wasting diseases. Anabolic properties are not only therapeutically beneficial to critically ill and debilitated patients, but are also desirable to athletes seeking artificial enhancements in endurance, strength and accelerated recovery. The use of anabolic agents in the clinical setting is being reconsidered with the emergence of a new class of drugs referred to as SARMs (selective androgen receptor modulators). SARMs have the potential to complement or even replace anabolic androgenic steroidal use with the benefit of a reduction of the undesirable side effects associated with steroid administration alone. Arylpropionamide-based SARMs such as andarine (S-4) and S-22 have shown promising therapeutic properties and have attracted the interest of elite and amateur athletes despite the absence of clinical approval, and evidence for trafficking and misuse in sport has been obtained by doping control authorities. In this communication, the elucidation of urinary metabolites of the SARM drug candidate S-22 is compared with earlier in vitro metabolism studies. Following oral administration of illicit S-22, urine samples were collected after 62 and 135 h and analyzed for the active drug and its major metabolic products. Liquid chromatography interfaced with high-resolution/high-accuracy (tandem) mass spectrometry was used to identify and/or confirm the predicted target analytes for sports drug testing purposes. S-22 was detected in both specimens accompanied by its glucuronic acid conjugate. This was the B-ring hydroxylated derivative of S-22 plus the corresponding glucuronide (with the phase-II metabolites being the more abundant analytes). In addition, the samples collected 62 h post-administration also contained the phase-I metabolite hydroxylated at the methyl residue (C-20

  9. Development of Thermal Dissociation Atmospheric Chemical Ionization Source for Rapid Mass Spectrometric Analysis of Ambient Samples%常压热解离化学电离源的研制及表征

    Institute of Scientific and Technical Information of China (English)

    韩京; 李建强; 张燮; 胡斌; 罗明标; 陈焕文

    2011-01-01

    A novel thermal dissociation atmospheric chemical ionization source (TDCI) was developed for rapid chemical ionization of ambient analytes in complex matrices. By coupling the TDCI source to a commercial LTQ XL mass spectrometer, the dissociation of chemical reagents such as ionic liquids was systematically investigated using multiple-stage mass spectrometric experiments. The primary ions generated through the thermal dissociation process of the ionic liquids were accelerated by the high voltage applied on the repelling electrode of the TDCI source, and then reacted with the analytes present in the matrices of the raw samples to produce ions of analytes, which were then guided to the LTQ instrument for mass analysis. The construction of the TDCI source was detailed in the text. The effects of the experimental parameters such as the pyrolysis temperature, the distance, and the angles formed between the electrodes were experimentally studied using the signals of characteristic fragments of the ionic liquid. Under the optimal experimental parameters, TDCI was able to directly ionize a wide variety of compounds, including the poplar (e.g., amino acids, doping compounds) and non-polar chemicals (e.g, naphthalene) for sensitive detection using LTQ-MS, without any sample pretreatment. The average time for a single sample analysis was less than 30 s, and the relative standard deviation of the method was in the range of 5.9%- 11.1 %; the LOD for naphthalene was estimated to be 2.93 × 10-7 g/L.%自行研制了常压热解离化学电离源(TDCI),与商品化LTQ XL质谱仪成功联用,进一步考察了TDCI的性能,并对其应用领域进行了初步探索.TDCI-MS/MS谱图表明,离子液体可在现有实验条件下产生特征离子碎片;升高TDCI源偏置电压和温度,可以提高离子液体的信号强度.基于优化后的实验参数,常压热解离化学电离质谱方法(TDCI-MS)可以有效检测沙丁胺醇和萘等极性与非极性物质.本方法

  10. Improved precision and accuracy for high-performance liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometric exact mass measurement of small molecules from the simultaneous and controlled introduction of internal calibrants via a second electrospray nebuliser.

    Science.gov (United States)

    Herniman, Julie M; Bristow, Tony W T; O'Connor, Gavin; Jarvis, Jackie; Langley, G John

    2004-01-01

    The use of a second electrospray nebuliser has proved to be highly successful for exact mass measurement during high-performance liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry (HPLC/FTICRMS). Much improved accuracy and precision of mass measurement were afforded by the introduction of the internal calibration solution, thus overcoming space charge issues due to the lack of control over relative ion abundances of the species eluting from the HPLC column. Further, issues of suppression of ionisation, observed when using a T-piece method, are addressed and this simple system has significant benefits over other more elaborate approaches providing data that compares very favourably with these other approaches. The technique is robust, flexible and transferable and can be used in conjunction with HPLC, infusion or flow injection analysis (FIA) to provide constant internal calibration signals to allow routine, accurate and precise mass measurements to be recorded.

  11. Li^+ attachment mass spectrometric investigation of high-mass neutral species in the downstream region of Ar/CF4, Ar/CF4/O2 and Ar/CF4/H2 plasmas

    Science.gov (United States)

    Furuya, Kenji; Okumura, Hiroshi; Tamai, Yuji; Ide, Akihiro; Harata, Akira

    2008-10-01

    Recently gaseous high-mass species have received significant attentions as important contributors to the nucleation of films and particulates in fluorocarbon plasmas. We have unambiguously identified the gaseous high-mass neutral species in the downstream region of the Ar/CF4 plasma [1], using the Li^+ attachment ionization technique that is a fragment-free ionization method. In this report, we show the results of mass analysis of high-mass neutral species in the Ar/CF4/O2 and Ar/CF4/H2 plasmas as well as Ar/CF4. In the Ar/CF4 plasma, we observed CnF2n+2 (n = 2-7) and CnF2n (n = 4-8) as neutral species. Adding O2 to the Ar/CF4 plasma resulted in the intensity decrease of CnF2n+2 and CnF2n, especially of those with relatively small n values. CnF2nO (n = 1-7) were newly observed in the Ar/CF4/O2 plasma. In contrast, adding H2 to the Ar/CF4 plasma resulted in the production of various new compounds, such as CnF2n-2 (n=3-8), CnF2n-4 (n=3-9), CnF2n+1H (n=1-7), CnF2n-1H (n=2-8), CnF2n-3H (n=4-9) and CnF2n-5H (n=5-9). These species are produced through the abstraction of F from various CnFm species by the H radical and the addition of H to them. [1] K. Furuya, S. Yukita, H. Okumura, A. Harata, Chem. Lett. 34, 224 (2005).

  12. Knudsen effusion mass spectrometry. Chapter 20

    International Nuclear Information System (INIS)

    The Knudsen effusion mass spectrometric method for the determination of vapour pressures and thermodynamic properties is described. The aim of the article is to give a general introduction to the method rather than to give a critical review of the technique. The latest developments in this area of research are reviewed by the peers in the field during the triennial international mass spectrometric conferences. The Knudsen effusion mass spectrometric method is being applied for thermodynamic measurements. In recent times, laser vaporisation mass spectrometric methods have emerged as a source of determination of vapour pressures at very high temperatures and beyond the pressure regime far exceeding Knudsen effusion range

  13. Minimization of mass interferences in quadrupole inductively coupled plasma mass spectrometric (ICP-MS) determination of palladium using a flow injection on-line displacement solid-phase extraction protocol

    Energy Technology Data Exchange (ETDEWEB)

    Fang Jing [Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071 (China); Liu Liwen [Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071 (China); Yan Xiuping [Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071 (China)]. E-mail: xpyan@nankai.edu.cn

    2006-07-15

    A flow injection on-line displacement solid-phase extraction protocol was employed to minimize mass interferences with determination of palladium by inductively coupled plasma mass spectrometry (ICP-MS). The developed method involved in on-line complexing of Ag{sup +} with pyrrolidine dithiocarbamate (PDC), presorption of the resultant Ag-PDC onto a microcolumn packed with the cigarette filter, displacement sorption of Pd{sup 2+} through loading the sample solution onto the microcolumn due to on-line displacement reaction between Pd{sup 2+} and the presorbed Ag-PDC, elution of the retained Pd{sup 2+} with 50 {mu}L of ethanol for on-line ICP-MS detection. Interferences from co-existing heavy metal ions with lower stability of their PDC complexes relative to Ag-PDC were minimized/eliminated. No interferences from 5 mg L{sup -1} Zn and 3 mg L{sup -1} Pb for {sup 104}Pd, 0.4 mg L{sup -1} Cu for {sup 105}Pd, 6 mg L{sup -1} Zn and 2 mg L{sup -1} Cd for {sup 106}Pd, 6 mg L{sup -1} Zn and 3 mg L{sup -1} Cd for {sup 108}Pd, and 2 mg L{sup -1} Cd for {sup 110}Pd were observed for the determination of 100 ng L{sup -1} Pd. The enhancement factors of 71-75, sample throughput of 23 samples h{sup -1} and detection limits of 2.8-3.5 ng L{sup -1} were achieved with the consumption of 3.0 mL of sample solution. The precision (RSD) for eleven replicate determinations of Pd at the 100 ng L{sup -1} level was 1.8-2.7%. The developed method was applied to the determination of palladium in rock samples.

  14. Minimization of mass interferences in quadrupole inductively coupled plasma mass spectrometric (ICP-MS) determination of palladium using a flow injection on-line displacement solid-phase extraction protocol

    Science.gov (United States)

    Fang, Jing; Liu, Li-Wen; Yan, Xiu-Ping

    2006-07-01

    A flow injection on-line displacement solid-phase extraction protocol was employed to minimize mass interferences with determination of palladium by inductively coupled plasma mass spectrometry (ICP-MS). The developed method involved in on-line complexing of Ag + with pyrrolidine dithiocarbamate (PDC), presorption of the resultant Ag-PDC onto a microcolumn packed with the cigarette filter, displacement sorption of Pd 2+ through loading the sample solution onto the microcolumn due to on-line displacement reaction between Pd 2+ and the presorbed Ag-PDC, elution of the retained Pd 2+ with 50 μL of ethanol for on-line ICP-MS detection. Interferences from co-existing heavy metal ions with lower stability of their PDC complexes relative to Ag-PDC were minimized/eliminated. No interferences from 5 mg L - 1 Zn and 3 mg L - 1 Pb for 104Pd, 0.4 mg L - 1 Cu for 105Pd, 6 mg L - 1 Zn and 2 mg L - 1 Cd for 106Pd, 6 mg L - 1 Zn and 3 mg L - 1 Cd for 108Pd, and 2 mg L - 1 Cd for 110Pd were observed for the determination of 100 ng L - 1 Pd. The enhancement factors of 71-75, sample throughput of 23 samples h - 1 and detection limits of 2.8-3.5 ng L - 1 were achieved with the consumption of 3.0 mL of sample solution. The precision (RSD) for eleven replicate determinations of Pd at the 100 ng L - 1 level was 1.8-2.7%. The developed method was applied to the determination of palladium in rock samples.

  15. Minimization of mass interferences in quadrupole inductively coupled plasma mass spectrometric (ICP-MS) determination of palladium using a flow injection on-line displacement solid-phase extraction protocol

    International Nuclear Information System (INIS)

    A flow injection on-line displacement solid-phase extraction protocol was employed to minimize mass interferences with determination of palladium by inductively coupled plasma mass spectrometry (ICP-MS). The developed method involved in on-line complexing of Ag+ with pyrrolidine dithiocarbamate (PDC), presorption of the resultant Ag-PDC onto a microcolumn packed with the cigarette filter, displacement sorption of Pd2+ through loading the sample solution onto the microcolumn due to on-line displacement reaction between Pd2+ and the presorbed Ag-PDC, elution of the retained Pd2+ with 50 μL of ethanol for on-line ICP-MS detection. Interferences from co-existing heavy metal ions with lower stability of their PDC complexes relative to Ag-PDC were minimized/eliminated. No interferences from 5 mg L-1 Zn and 3 mg L-1 Pb for 104Pd, 0.4 mg L-1 Cu for 105Pd, 6 mg L-1 Zn and 2 mg L-1 Cd for 106Pd, 6 mg L-1 Zn and 3 mg L-1 Cd for 108Pd, and 2 mg L-1 Cd for 110Pd were observed for the determination of 100 ng L-1 Pd. The enhancement factors of 71-75, sample throughput of 23 samples h-1 and detection limits of 2.8-3.5 ng L-1 were achieved with the consumption of 3.0 mL of sample solution. The precision (RSD) for eleven replicate determinations of Pd at the 100 ng L-1 level was 1.8-2.7%. The developed method was applied to the determination of palladium in rock samples

  16. ACTIVITY - BASED COSTING DESIGNING

    OpenAIRE

    Wioletta Skibiñska; Marta Kad³ubek

    2010-01-01

    The traditional costing system sometimes does not give accurate information about the consumption of different resources and the activities of the organisation. The activity-based costing system is an information-rich costing system which is more and more necessary for the success of many European companies. Base of designing and implementation of an ABC system in the enterprises are presented in the article.

  17. Development and validation of highly selective screening and confirmatory methods for the qualitative forensic analysis of organic explosive compounds with high performance liquid chromatography coupled with (photodiode array and) LTQ ion trap/Orbitrap mass spectrometric detections (HPLC-(PDA)-LTQOrbitrap).

    Science.gov (United States)

    Xu, Xiaoma; Koeberg, Mattijs; Kuijpers, Chris-Jan; Kok, Eric

    2014-01-01

    An LTQ-Orbitrap FTMS is a new (hybrid) mass spectrometric (MS) analyzer. It allows for the acquisition of full scan MS(n) (n-stage fragmentations, n=1-n) spectra with the linear ion trap detector (LTQ) at high speed and/or with the Fourier Transform-detector (Orbitrap) with ultra high mass resolution (>60,000 at m/z17025 and NEN 7777). The methods are highly selective due to the simultaneous utilization of the Orbitrap FTMS and LTQ MS(2), both of which are highly selective detectors Tested explosive compounds can be detected in the molecular ion form by the Orbitrap analyzer with minimal mass interference in different matrices when using an extremely narrow mass tolerance detection window (≤2ppm). The identification of a detected compound follows an identification point system. Experimental results show that almost all explosive compounds meet the confirmation criteria (minimum 4 points) required for the positive identification by the DC 2002/657/EC. PMID:24438773

  18. Substrate-Enhanced Micro Laser Desorption Ionization Mass Spectrometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerodyne Research, Inc. and the University of Massachusetts at Amherst will collaborate to develop laser desorption ionization (LDI) mass spectrometric analysis of...

  19. Development and validation of highly selective screening and confirmatory methods for the qualitative forensic analysis of organic explosive compounds with high performance liquid chromatography coupled with (photodiode array and) LTQ ion trap/Orbitrap mass spectrometric detections (HPLC-(PDA)-LTQOrbitrap).

    Science.gov (United States)

    Xu, Xiaoma; Koeberg, Mattijs; Kuijpers, Chris-Jan; Kok, Eric

    2014-01-01

    An LTQ-Orbitrap FTMS is a new (hybrid) mass spectrometric (MS) analyzer. It allows for the acquisition of full scan MS(n) (n-stage fragmentations, n=1-n) spectra with the linear ion trap detector (LTQ) at high speed and/or with the Fourier Transform-detector (Orbitrap) with ultra high mass resolution (>60,000 at m/zphoto diode array (PDA) detection. Two methods for the forensic screening and confirmation of all common trace explosives in post-blast residues have been developed on this instrument using atmospheric pressure chemical ionization (APCI). In one run, the nitrogen-containing explosives are analyzed with the combination of "LC-(PDA)-APCI(-)-LTQ MS(2)/Orbitrap FTMS" (Method 1). In another run, peroxide explosives are analyzed with "LC-APCI(+)-LTQ MS(2)/Orbitrap FTMS" (Method 2). The performance of both methods has been validated according to procedures defined in the EU COMMISSION DECISION implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results (DC 2002/657/EC) and other standards (NEN 17025 and NEN 7777). The methods are highly selective due to the simultaneous utilization of the Orbitrap FTMS and LTQ MS(2), both of which are highly selective detectors Tested explosive compounds can be detected in the molecular ion form by the Orbitrap analyzer with minimal mass interference in different matrices when using an extremely narrow mass tolerance detection window (≤2ppm). The identification of a detected compound follows an identification point system. Experimental results show that almost all explosive compounds meet the confirmation criteria (minimum 4 points) required for the positive identification by the DC 2002/657/EC.

  20. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Robert De Levie

    2009-09-01

    The spectrometric analysis of a mixture of two chemically and spectroscopically similar compounds is illustrated for the simultaneous spectrometric determination of caffeine and theobromine, the primary stimulants in coffee and tea, based on their ultraviolet absorbances. Their analysis indicates that such measurements may need an unexpectedly high precision to yield accurate answers, because of an artifact of inverse cancellation, in which a small noise or drift signal is misinterpreted in terms of a concentration difference. The computed sum of the concentrations is not affected.