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Sample records for high-resolution time-of-flight mass

  1. A High-Resolution Time-of-Flight Mass Spectrometer for Experiments with Ultracold Gases

    CERN Document Server

    Kraft, S D; Staanum, P; Fioretti, A; Lange, J; Wester, R; Weidemüller, M; Kraft, Stephan D.; Mikosch, Jochen; Staanum, Peter; Fioretti, Andrea; Lange, Joerg; Wester, Roland; Weidemueller, Matthias

    2005-01-01

    We have realized a high-resolution time-of-flight mass spectrometer combined with a magneto-optical trap. The spectrometer enables excellent optical access to the trapped atomic cloud using properly devised acceleration and deflection electrodes. The ions are extracted along a laser axis and deflected onto an off axis detector. The setup is applied to detect atoms and molecules photoassociated from ultracold atoms. The detection is based on resonance-enhanced multi-photon ionization. The versatile setup can easily be implemented in more complex experiments with ultracold atomic and molecular gases. Mass resolution up to $m/\\Delta m_{rms} = 1000$ at the mass of $^{133}$Cs is achieved.

  2. New high-resolution electrostatic ion mass analyzer using time of flight

    Science.gov (United States)

    Hamilton, D. C.; Gloeckler, G.; Ipavich, F. M.; Lundgren, R. A.; Sheldon, R. B.

    1990-01-01

    The design of a high-resolution ion-mass analyzer is described, which is based on an accurate measurement of the time of flight (TOF) of ions within a region configured to produce a harmonic potential. In this device, the TOF, which is independent of ion energy, is determined from a start pulse from secondary electrons produced when the ion passes through a thin carbon foil at the entrance of the TOF region and at a stop pulse from the ion striking a microchannel plate upon exciting the region. A laboratory prototype instrument called 'VMASS' was built and was tested at the Goddard Space Flight Center electrostatic accelerator, showing a good mass resolution of the instrument. Sensors of the VMASS type will form part of the WIND Solar Wind and Suprathermal Ion experiment, the Soho mission, and the Advanced Composition Explorer.

  3. Mobile high-resolution time-of-flight mass spectrometer for in-situ analytics

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Johannes; Ebert, Jens [II. Physikalisches Institut, JLU, Giessen (Germany); Dickel, Timo; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [II. Physikalisches Institut, JLU, Giessen (Germany); GSI, Darmstadt (Germany)

    2011-07-01

    A compact multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been developed. For the first time it allows for mass measurements with a resolving power exceeding 100000 and sub ppm accuracy in a mobile device. Thus it allows to resolve isobars and enables to accurately determine the composition and structure of biomolecules. The MR-TOF-MS consists of an atmospheric pressure interface for DESI and REIMS, ion cooler, ion trap, time-of-flight analyzer, MCP detector and DAQ. Vacuum system components, power supplies as well as electronics are mounted together with the ion optical spectrometer parts on a single frame with a total volume of 0.8 m{sup 3}. Applications of the device within the AmbiProbe research program include in-situ mass spectrometry such as real-time tissue recognition in electrosurgery, identification of mycotoxins and analysis of soil samples for environmental studies.

  4. Clustering, methodology, and mechanistic insights into acetate chemical ionization using high-resolution time-of-flight mass spectrometry

    Science.gov (United States)

    Brophy, Patrick; Farmer, Delphine K.

    2016-08-01

    We present a comprehensive characterization of cluster control and transmission through the Tofwerk atmospheric pressure interface installed on various chemical ionization time-of-flight mass spectrometers using authentic standards. This characterization of the atmospheric pressure interface allows for a detailed investigation of the acetate chemical ionization mechanisms and the impact of controlling these mechanisms on sensitivity, selectivity, and mass spectral ambiguity with the aim of non-targeted analysis. Chemical ionization with acetate reagent ions is controlled by a distribution of reagent ion-neutral clusters that vary with relative humidity and the concentration of the acetic anhydride precursor. Deprotonated carboxylic acids are primarily detected only if sufficient declustering is employed inside the atmospheric pressure interface. The configuration of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) using an acetate chemical ionization source for non-targeted analysis is discussed. Recent approaches and studies characterizing acetate chemical ionization as it applies to the HR-TOF-CIMS are evaluated in light of the work presented herein.

  5. Determination of stimulants using gas chromatography/high-resolution time-of-flight mass spectrometry and a soft ionization source.

    Science.gov (United States)

    Lopez-Avila, Viorica; Cooley, James; Urdahl, Randall; Thevis, Mario

    2012-12-15

    The aim of this study was to investigate the mass spectral fragmentation of a small set of stimulants in a high-resolution time-of-flight mass spectrometer equipped with a soft ionization source using vacuum ultraviolet (VUV) photons emitted from different plasma gases. It was postulated that the use of a plasma gas such as Xe, which emits photons at a lower energy than Kr or Ar, would lead to softer ionization of the test compounds, and thus to less fragmentation. A set of nine stimulants: cocaine, codeine, nicotine, methadone, phenmetrazine, pentylenetetrazole, niketamide, fencamfamine, and caffeine, was analyzed by gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) in positive ion mode with this soft ionization source, using either Xe, Kr, or Ar as plasma gases. Working solutions of the test compounds at 0.1 to 100 ng/μL were used to establish instrument sensitivity and linearity. All test compounds, except methadone and pentylenetetrazole, exhibited strong molecular ions and no fragmentation with Xe-microplasma photoionization (MPPI). Methadone exhibited significant fragmentation not only with Xe, but also with Kr and Ar, and pentylenetetrazole could not be ionized with Xe, probably because its ionization energy is above 8.44 eV. The Kr- and Ar-MPPI mass spectra of the test compounds showed that the relative intensity of the molecular ion decreased as the photon energy increased. When coupled to a TOF mass spectrometer this soft ionization source has demonstrated signal-to-noise (S/N) ratios from 7 to 730 at 100 pg per injection (depending on the compound), and a dynamic range of three orders of magnitude (100 pg to 100 ng) for some of the test compounds. Copyright © 2012 John Wiley & Sons, Ltd.

  6. Multi-detection of corticosteroids in sports doping and veterinary control using high-resolution liquid chromatography/time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Touber, M.E.; Engelen, M.C.; Georgakopoulus, C.; Rhijn, van J.A.; Nielen, M.W.F.

    2007-01-01

    A liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) method was developed using the latest high-resolution LC column technology, the ultra performance liquid chromatography (UPLC (TM)), and electrospray ionization (ESI) in the positive ion mode. Gradient UPLC separation conditions wer

  7. Direct determination of acrylamide in food by gas chromatography-high-resolution time-of-flight mass spectrometry.

    Science.gov (United States)

    Dunovská, Lenka; Cajka, Tomás; Hajslová, Jana; Holadová, Katerina

    2006-09-25

    Simple and rapid gas chromatographic (GC) method employing a high-resolution time-of-flight mass analyzer that enables direct analysis (no derivatization) of acrylamide in various heat-processed foodstuffs has been developed and validated. Co-isolation of acrylamide precursors such as sugars and asparagine, constituting the risk of results overestimation due to additional formation of analyte in hot GC injector, is avoided by the extraction with n-propanol followed by solvent exchange to acetonitrile (MeCN). Introduction of a novel purification strategy, dispersive solid phase extraction, based on addition of primary-secondary amine (PSA) sorbent into deffated extract in MeCN, provides a significant reduction of some abundant matrix co-extracts (mainly free fatty acids). Isotope dilution technique (d3-acrylamide as an internal standard) is employed for compensation of potential target analyte losses and/or matrix-inducted chromatographic response enhancement. Limits of quantifications (LOQs) ranged between 15 and 40 microg kg(-1) and recoveries were between 97 and 108% depending on the examined food matrix. The repeatability of measurements (expressed as relative standard deviation, R.S.D.) was as low as 1.9% for potato crisps containing acrylamide at a level of 1 mg kg(-1). Slightly higher values (R.S.D.<4.0%) were achieved for breakfast cereals and crisp bread with approximately 10 times lower content of this processing contaminant. Trueness of results generated by this new method was demonstrated via FAPAS (Food Analysis Performance Assessment Scheme) interlaboratory proficiency tests.

  8. Direct determination of acrylamide in food by gas chromatography-high-resolution time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dunovska, Lenka [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic); Cajka, Tomas [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic); Hajslova, Jana [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic)]. E-mail: jana.hajslova@vscht.cz; Holadova, Katerina [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic)

    2006-09-25

    Simple and rapid gas chromatographic (GC) method employing a high-resolution time-of-flight mass analyzer that enables direct analysis (no derivatization) of acrylamide in various heat-processed foodstuffs has been developed and validated. Co-isolation of acrylamide precursors such as sugars and asparagine, constituting the risk of results overestimation due to additional formation of analyte in hot GC injector, is avoided by the extraction with n-propanol followed by solvent exchange to acetonitrile (MeCN). Introduction of a novel purification strategy, dispersive solid phase extraction, based on addition of primary-secondary amine (PSA) sorbent into deffated extract in MeCN, provides a significant reduction of some abundant matrix co-extracts (mainly free fatty acids). Isotope dilution technique (d{sub 3}-acrylamide as an internal standard) is employed for compensation of potential target analyte losses and/or matrix-inducted chromatographic response enhancement. Limits of quantifications (LOQs) ranged between 15 and 40 {mu}g kg{sup -1} and recoveries were between 97 and 108% depending on the examined food matrix. The repeatability of measurements (expressed as relative standard deviation, R.S.D.) was as low as 1.9% for potato crisps containing acrylamide at a level of 1 mg kg{sup -1}. Slightly higher values (R.S.D. < 4.0%) were achieved for breakfast cereals and crisp bread with approximately 10 times lower content of this processing contaminant. Trueness of results generated by this new method was demonstrated via FAPAS[reg] (Food Analysis Performance Assessment Scheme) interlaboratory proficiency tests.

  9. An iodide-adduct high-resolution time-of-flight chemical-ionization mass spectrometer: application to atmospheric inorganic and organic compounds.

    Science.gov (United States)

    Lee, Ben H; Lopez-Hilfiker, Felipe D; Mohr, Claudia; Kurtén, Theo; Worsnop, Douglas R; Thornton, Joel A

    2014-06-03

    A high-resolution time-of-flight chemical-ionization mass spectrometer (HR-ToF-CIMS) using Iodide-adducts has been characterized and deployed in several laboratory and field studies to measure a suite of organic and inorganic atmospheric species. The large negative mass defect of Iodide, combined with soft ionization and the high mass-accuracy (5500) of the time-of-flight mass spectrometer, provides an additional degree of separation and allows for the determination of elemental compositions for the vast majority of detected ions. Laboratory characterization reveals Iodide-adduct ionization generally exhibits increasing sensitivity toward more polar or acidic volatile organic compounds. Simultaneous retrieval of a wide range of mass-to-charge ratios (m/Q from 25 to 625 Th) at a high frequency (>1 Hz) provides a comprehensive view of atmospheric oxidative chemistry, particularly when sampling rapidly evolving plumes from fast moving platforms like an aircraft. We present the sampling protocol, detection limits and observations from the first aircraft deployment for an instrument of this type, which took place aboard the NOAA WP-3D aircraft during the Southeast Nexus (SENEX) 2013 field campaign.

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

    Science.gov (United States)

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

    2016-08-01

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

  11. [Application of gas chromatography-high resolution quadrupole time of flight mass spectrometry to the analysis of benzaldehyde, benzyl alcohol acetophenone and phenylacetaldehyde in complex aromatic samples].

    Science.gov (United States)

    Liu, Junyan; Cao, Zhe; Li, Jiwen; Wang, Zheming; Wang, Chuan; Gu, Songyuan

    2015-02-01

    The study focuses on the quantitative analytical characterization of benzaldehyde, benzyl alcohol, acetophenone and phenylacetaldehyde in complex aromatic samples by gas chromatography-high resolution quadrupole time of flight mass spectrometry (GC-QTOF MS). The four compounds in real sample were accurately qualified and quantified through a comprehensive analysis of the GC retention times and the accurate masses of the ion fragments obtained by the high resolution MS. The new method therefore effectively avoids the interference of the real sample substrate, which reduces the accuracy of the analysis results. The peak area of the characteristic ion fragment for each compound was used for quantitation calculation. The MS signal responses of the four compounds showed good linear relationships with the corresponding mass concentrations and the linear regression coefficients were greater than 0. 99. The method recoveries were 87. 97% - 103.01%. The limits of detection (LODs) were 0. 01, 0. 03, 0. 02 and 0. 01 mg/L for benzaldehyde, benzyl alcohol, acetophenone and phenylacetaldehyde respectively. The contents of the four compounds in three real samples were analyzed. The study provided a new strategy for oxygenate analysis in complex aromatic samples using GC-QTOF MS. By measuring the accurate masses, the new method reduces the reliance on chromatographic separation ability and makes up the shortcomings of the traditional GC-MS methods.

  12. Further development and application of a mobile multiple-reflection time-of-flight mass spectrometer for analytical high-resolution tandem mass spectrometry

    OpenAIRE

    Lippert, Wayne

    2016-01-01

    In this work, a mobile multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) for analytical mass spectrometry was enhanced in many important aspects. Technical as well as software-based improvements have been added to the instrument, thus greatly increasing its performance and applicability. Changes have been applied to the whole beam preparation system of the MR-TOF-MS. In this context, the electronic setup was completely overhauled and a quadrupole mass filter was commissioned. C...

  13. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically-resolved aerosol fluxes

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2010-12-01

    Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM1 fluxes. Average deposition velocity for total NR-PM1 aerosol at noon was 2.05 ± 0.04 mm/s. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm/s and are dominated by deposition of ammonium sulphate.

  14. Screening of environmental contaminants in honey bee wax comb using gas chromatography-high-resolution time-of-flight mass spectrometry.

    Science.gov (United States)

    Gómez-Ramos, M M; García-Valcárcel, A I; Tadeo, J L; Fernández-Alba, A R; Hernando, M D

    2016-03-01

    This study reports an analytical approach intended to be used for investigation of non-targeted environmental contaminants and to characterize the organic pollution pattern of bee wax comb samples. The method comprises a generic extraction followed by detection with gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF-MS), operated in electron impact ionization (EI) mode. The screening approach for the investigation of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS(1) with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, the molecular formula of representative ions (molecular ion when present in the EI spectrum) and, for at least other two fragment ions, was provided for those with an accurate mass scoring (mass error bee wax comb. This approach has allowed the tentative identification of some GC-amenable contaminants belonging to different chemical groups, among them, phthalates and polycyclic aromatic hydrocarbons (PAHs), along with residues of veterinary treatments used in apiculture.

  15. Chemical Characteristics of Particulate Matter from Vehicle emission using High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS)

    Science.gov (United States)

    Park, T.; Lee, T.; Kang, S.; Lee, J.; Kim, J.; Son, J.; Yoo, H. M.; Kim, K.; Park, G.

    2015-12-01

    Car emissions are major contributors of particulate matter (PM) in the urban environment and effects of air pollution, climate change, and human activities. By increasing of interest in research of car emission for assessment of the PM control, it became require to understand the chemical composition and characteristics of the car exhaust gases and particulate matter. To understand car emission characteristics of PM, we will study PM of car emissions for five driving modes (National Institute Environmental Research (NIER)-5, NIER-9, NIER-12, NIER-14) and three fixed speed driving modes (30km/h, 70km/h, 110km/h) using different fuel types (gasoline, diesel, and LPG) at Transportation Pollution Research Center (TPRC) of NIER in Incheon, South Korea. PM chemical composition of car emission was measured for concentrations of organics, sulfate, nitrate, ammonium, PAHs, oxidation states and size distribution using an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and engine exhaust particle sizer (EEPS) on real-time. In the study, organics concentration was dominated for all cases of driving modes and the concentration of organics was increased in 110km/h fixed speed mode for gasoline and diesel. The presentation will provide an overview of the chemical composition of PM in the car emissions.

  16. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2011-06-01

    Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM1 fluxes. Average deposition velocities for total NR-PM1 aerosol at noon were 2.05 ± 0.04 mm s−1. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s−1 and are dominated by deposition of ammonium sulphate.

  17. Characterization of biomass burning smoke from cooking fires, peat, crop residue and other fuels with high resolution proton-transfer-reaction time-of-flight mass spectrometry

    Science.gov (United States)

    Stockwell, C. E.; Veres, P. R.; Williams, J.; Yokelson, R. J.

    2014-08-01

    We deployed a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure biomass burning emissions from peat, crop-residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combination of gas standards calibrations and composition sensitive, mass dependent calibration curves were applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign best identities to most major "exact masses" including many high molecular mass species. Using these methods approximately 80-96% of the total NMOC mass detected by PTR-TOF-MS and FTIR was positively or tentatively identified for major fuel types. We report data for many rarely measured or previously unmeasured emissions in several compound classes including aromatic hydrocarbons, phenolic compounds, and furans; many of which are suspected secondary organic aerosol precursors. A large set of new emission factors (EFs) for a range of globally significant biomass fuels is presented. Measurements show that oxygenated NMOCs accounted for the largest fraction of emissions of all compound classes. In a brief study of various traditional and advanced cooking methods, the EFs for these emissions groups were greatest for open 3-stone cooking in comparison to their more advanced counterparts. Several little-studied nitrogen-containing organic compounds were detected from many fuel types that together accounted for 0.1-8.7% of the fuel nitrogen and some may play a role in new particle formation.

  18. Characterization of biomass burning emissions from cooking fires, peat, crop residue, and other fuels with high-resolution proton-transfer-reaction time-of-flight mass spectrometry

    Science.gov (United States)

    Stockwell, C. E.; Veres, P. R.; Williams, J.; Yokelson, R. J.

    2015-01-01

    We deployed a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure biomass-burning emissions from peat, crop residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combination of gas standard calibrations and composition sensitive, mass-dependent calibration curves was applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign the best identities to most major "exact masses", including many high molecular mass species. Using these methods, approximately 80-96% of the total NMOC mass detected by the PTR-TOF-MS and Fourier transform infrared (FTIR) spectroscopy was positively or tentatively identified for major fuel types. We report data for many rarely measured or previously unmeasured emissions in several compound classes including aromatic hydrocarbons, phenolic compounds, and furans; many of these are suspected secondary organic aerosol precursors. A large set of new emission factors (EFs) for a range of globally significant biomass fuels is presented. Measurements show that oxygenated NMOCs accounted for the largest fraction of emissions of all compound classes. In a brief study of various traditional and advanced cooking methods, the EFs for these emissions groups were greatest for open three-stone cooking in comparison to their more advanced counterparts. Several little-studied nitrogen-containing organic compounds were detected from many fuel types, that together accounted for 0.1-8.7% of the fuel nitrogen, and some may play a role in new particle formation.

  19. A two stage algorithm for target and suspect analysis of produced water via gas chromatography coupled with high resolution time of flight mass spectrometry.

    Science.gov (United States)

    Samanipour, Saer; Langford, Katherine; Reid, Malcolm J; Thomas, Kevin V

    2016-09-09

    Gas chromatography coupled with high resolution time of flight mass spectrometry (GC-HR-TOFMS) has gained popularity for the target and suspect analysis of complex samples. However, confident detection of target/suspect analytes in complex samples, such as produced water, remains a challenging task. Here we report on the development and validation of a two stage algorithm for the confident target and suspect analysis of produced water extracts. We performed both target and suspect analysis for 48 standards, which were a mixture of 28 aliphatic hydrocarbons and 20 alkylated phenols, in 3 produced water extracts. The two stage algorithm produces a chemical standard database of spectra, in the first stage, which is used for target and suspect analysis during the second stage. The first stage is carried out through five steps via an algorithm here referred to as unique ion extractor (UIE). During the first step the m/z values in the spectrum of a standard that do not belong to that standard are removed in order to produce a clean spectrum and then during the last step the cleaned spectrum is calibrated. The Dot-product algorithm, during the second stage, uses the cleaned and calibrated spectra of the standards for both target and suspect analysis. We performed the target analysis of 48 standards in all 3 samples via conventional methods, in order to validate the two stage algorithm. The two stage algorithm was demonstrated to be more robust, reliable, and less sensitive to the signal-to-noise ratio (S/N), when compared to the conventional method. The Dot-product algorithm showed lower potential in producing false positives compared to the conventional methods, when dealing with complex samples. We also evaluated the effect of the mass accuracy on the performances of Dot-product algorithm. Our results indicated the crucial importance of HR-MS data and the mass accuracy for confident suspect analysis in complex samples.

  20. Comparison between drug screening by immunoassay and ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry in post-mortem urine.

    Science.gov (United States)

    Sundström, Mira; Pelander, Anna; Ojanperä, Ilkka

    2015-05-01

    Immunoassay is currently the most common approach for urine drug screening. However, the continuous emergence of new psychoactive substances (NPS) and their low urinary concentrations have challenged the scope and sensitivity of immunoassays. Consequently, specialized toxicology laboratories rely more and more on mass spectrometry (MS) based techniques. Ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOF-MS) is an especially attractive technique for comprehensive drug screening. The objective was to compare the performances of immunoassay and UHPLC-HR-TOF-MS in terms of scope, flexibility, sensitivity, and reliability of substance identification. A total of 279 post-mortem urine samples were analyzed using a method representative of each technique. The immunoassay method was an Emit II Plus enzyme immunoassay for the following drug groups: amphetamines, benzodiazepines, buprenorphine, cannabis, and opiates. The UHPLC-HR-TOF-MS method was a recently published method covering hundreds of drugs: conventional drugs of abuse, abused prescription drugs, and NPS of various classes. UHPLC-HR-TOF-MS produced a lower number of false positive (FP) results for the drug groups covered by immunoassay. Many of the false negative (FN, n = 40) and FP (n = 22) immunoassay results were obviously due to the higher cut-off concentrations and interfering matrix, respectively. Moreover, the wider scope of UHPLC-HR-TOF-MS allowed detection of NPS and prescription drugs. UHPLC-HR-TOF-MS gave FP results related to a few particular substances. The future option of adjusting all compound-specific reporting parameters individually would allow the method's sensitivity and specificity to be fully exploited.

  1. Characterization of the sources and processes of organic and inorganic aerosols in New York City with a high-resolution time-of-flight aerosol mass spectrometer

    Directory of Open Access Journals (Sweden)

    Y.-L. Sun

    2010-10-01

    Full Text Available Submicron aerosol particles (PM1 were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS during the summer 2009 Field Intensive Study at Queens College in New York City. Organic aerosol (OA and sulfate are the two dominant species, accounting for 54% and 24%, respectively, of total PM1 mass on average. The average mass size distribution of OA presents a small mode peaking at ~150 nm (Dva in addition to an accumulation mode (~550 nm that is internally mixed with sulfate, nitrate, and ammonium. The diurnal cycles of sulfate and OA both show pronounced peaks between 01:00–02:00 p.m. EST due to photochemical production. The average (±1σ oxygen-to-carbon (O/C, hydrogen-to-carbon (H/C, and nitrogen-to-carbon (N/C ratios of OA in NYC are 0.36 (±0.09, 1.49 (±0.08, and 0.012(±0.005, respectively, corresponding to an average organic mass-to-carbon (OM/OC ratio of 1.62(±0.11. Positive matrix factorization (PMF of the high resolution mass spectra identified five OA components: a hydrocarbon-like OA (HOA, two types of oxygenated OA (OOA including a low-volatility OOA (LV-OOA and a semi-volatile OOA (SV-OOA, a cooking-emission related OA (COA, and a unique nitrogen-enriched OA (NOA. HOA appears to represent primary OA (POA from urban traffic emissions. It comprises primarily of reduced species (H/C=1.83; O/C=0.06 and shows a mass spectral pattern very similar to those of POA from fossil fuel combustion, and correlates tightly with traffic emission tracers including elemental carbon and NOx. LV-OOA, which is highly oxidized (O/C=0.63 and correlates well with sulfate, appears to be representative for regional, aged secondary OA (SOA. SV-OOA, which is less oxidized (O/C=0.38 and correlates well with non-refractory chloride, likely represents less photo-chemically aged, semi-volatile SOA. COA shows a similar spectral pattern to the reference spectra of POA from

  2. Detection of atmospheric gaseous amines and amides by a high-resolution time-of-flight chemical ionization mass spectrometer with protonated ethanol reagent ions

    Science.gov (United States)

    Yao, Lei; Wang, Ming-Yi; Wang, Xin-Ke; Liu, Yi-Jun; Chen, Hang-Fei; Zheng, Jun; Nie, Wei; Ding, Ai-Jun; Geng, Fu-Hai; Wang, Dong-Fang; Chen, Jian-Min; Worsnop, Douglas R.; Wang, Lin

    2016-11-01

    Amines and amides are important atmospheric organic-nitrogen compounds but high time resolution, highly sensitive, and simultaneous ambient measurements of these species are rather sparse. Here, we present the development of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) method, utilizing protonated ethanol as reagent ions to simultaneously detect atmospheric gaseous amines (C1 to C6) and amides (C1 to C6). This method possesses sensitivities of 5.6-19.4 Hz pptv-1 for amines and 3.8-38.0 Hz pptv-1 for amides under total reagent ion signals of ˜ 0.32 MHz. Meanwhile, the detection limits were 0.10-0.50 pptv for amines and 0.29-1.95 pptv for amides at 3σ of the background signal for a 1 min integration time. Controlled characterization in the laboratory indicates that relative humidity has significant influences on the detection of amines and amides, whereas the presence of organics has no obvious effects. Ambient measurements of amines and amides utilizing this method were conducted from 25 July to 25 August 2015 in urban Shanghai, China. While the concentrations of amines ranged from a few parts per trillion by volume to hundreds of parts per trillion by volume, concentrations of amides varied from tens of parts per trillion by volume to a few parts per billion by volume. Among the C1- to C6-amines, the C2-amines were the dominant species with concentrations up to 130 pptv. For amides, the C3-amides (up to 8.7 ppb) were the most abundant species. The diurnal and backward trajectory analysis profiles of amides suggest that in addition to the secondary formation of amides in the atmosphere, industrial emissions could be important sources of amides in urban Shanghai. During the campaign, photo-oxidation of amines and amides might be a main loss pathway for them in daytime, and wet deposition was also an important sink.

  3. High-resolution time-of-flight mass spectrometry fingerprinting of metabolites from cecum and distal colon contents of rats fed resistant starch

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Timothy J. [Ames Laboratory; Jones, Roger W. [Ames Laboratory; Ai, Yongfeng [Iowa State University; Houk, Robert S. [Ames Laboratory; Jane, Jay-lin [Iowa State University; Zhao, Yinsheng [Iowa State University; Birt, Diane F. [Iowa State University; McClelland, John F. [Ames Laboratory

    2013-12-04

    Time-of-flight mass spectrometry along with statistical analysis was utilized to study metabolic profiles among rats fed resistant starch (RS) diets. Fischer 344 rats were fed four starch diets consisting of 55 % (w/w, dbs) starch. A control starch diet consisting of corn starch was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. A subgroup received antibiotic treatment to determine if perturbations in the gut microbiome were long lasting. A second subgroup was treated with azoxymethane (AOM), a carcinogen. At the end of the 8-week study, cecal and distal colon content samples were collected from the sacrificed rats. Metabolites were extracted from cecal and distal colon samples into acetonitrile. The extracts were then analyzed on an accurate-mass time-of-flight mass spectrometer to obtain their metabolic profile. The data were analyzed using partial least-squares discriminant analysis (PLS-DA). The PLS-DA analysis utilized a training set and verification set to classify samples within diet and treatment groups. PLS-DA could reliably differentiate the diet treatments for both cecal and distal colon samples. The PLS-DA analyses of the antibiotic and no antibiotic-treated subgroups were well classified for cecal samples and modestly separated for distal colon samples. PLS-DA analysis had limited success separating distal colon samples for rats given AOM from those not treated; the cecal samples from AOM had very poor classification. Mass spectrometry profiling coupled with PLS-DA can readily classify metabolite differences among rats given RS diets.

  4. Non-target screening of organic contaminants in marine salts by gas chromatography coupled to high-resolution time-of-flight mass spectrometry.

    Science.gov (United States)

    Serrano, Roque; Nácher-Mestre, Jaime; Portolés, Tania; Amat, Francisco; Hernández, Félix

    2011-08-15

    Gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF MS) has been applied to characterize the organic pollution pattern of marine salt samples collected in saltworks from the Spanish Mediterranean coast. After dissolving the samples in water, a solid-phase extraction was applied reaching with a 250-preconcentration factor. The screening methodology allowed the detection of sample components without any kind of pre-selection of target pollutants. The identity of components detected was established by accurate mass measurements and comparison of experimental full-acquisition spectra with theoretical MS libraries. Several organic pollutants were identified in the samples, like plasticizers - potentially toxic to humans - and fragrances -included within the group of pharmaceuticals and personal care products-, among others. Our results indicate that these contaminants can be found in the marine salt after the crystallization process. GC-TOF MS is a powerful technique for wide-scope screening of (semi)volatile, low-polar organic contaminants, able to investigate the presence of a large number of compounds. Searching of contaminants is not restricted to a target list of compounds. Therefore, unexpected contaminants can be discovered in an efficient way, with better sensitivity and selectivity than other conventional analytical techniques, and making use of the powerful qualitative information provided by full-spectrum acquisition at accurate mass.

  5. Analysis of selected designer benzodiazepines by UHPLC with high-resolution time-of-flight mass spectrometry and the estimation of their partition coefficients by micellar electrokinetic chromatography.

    Science.gov (United States)

    Tomková, Jana; Švidrnoch, Martin; Maier, Vítězslav; Ondra, Peter

    2017-03-07

    A new ultra high performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry method for the selective and sensitive separation, identification and determination of selected designer benzodiazepines (namely, pyrazolam, phenazepam, etizolam, flubromazepam, diclazepam, deschloroetizolam, bentazepam, nimetazepam and flubromazolam) in human serum was developed. The separation of the studied designer benzodiazepines was achieved on C18 chromatographic column using gradient elution within 6 min without any significant matrix interferences. Liquid-liquid extraction with butyl acetate was applied for serum samples clean-up and preconcentration of studied designer benzodiazepines. The method was validated in terms of linearity, limit of detection, limit of quantification, matrix effects, specificity, precision, accuracy, recovery and sample stability. The limit of detection values were in range 0.10-0.15 ng/mL. The method was applied on spiked serum sample to demonstrate its applicability for systematic toxicology analysis. Furthermore, a capillary chromatographic method with micellar electrokinetic chromatography was used for the estimation of partition coefficients of studied designer benzodiazepines as important parameters to evaluate their pharmacological and toxicological properties. This article is protected by copyright. All rights reserved.

  6. Highly segmented, high resolution time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

    1991-12-31

    The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

  7. Highly segmented, high resolution time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

    1991-12-31

    The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

  8. Selective extraction of halogenated compounds from data measured by comprehensive multidimensional gas chromatography/high resolution time-of-flight mass spectrometry for non-target analysis of environmental and biological samples.

    Science.gov (United States)

    Hashimoto, Shunji; Zushi, Yasuyuki; Fushimi, Akihiro; Takazawa, Yoshikatsu; Tanabe, Kiyoshi; Shibata, Yasuyuki

    2013-03-22

    We developed a method that selectively extracts a subset from comprehensive 2D gas chromatography (GC×GC) and high-resolution time-of-flight mass spectrometry (HRTOFMS) data to detect and identify trace levels of organohalogens. The data were obtained by measuring several environmental and biological samples, namely fly ash, soil, sediment, the atmosphere, and human urine. For global analysis, some samples were measured without purification. By using our novel software, the mass spectra of organochlorines or organobromines were then extracted into a data subset under high mass accuracy conditions that were approximately equivalent to a mass resolution of 6000 for some samples. Mass defect filtering as pre-screening for the data extraction was very effective in removing the mass spectra of hydrocarbons. Those results showed that data obtained with HRTOFMS are valuable for global analysis of organohalogens, and probably of other compounds if specific data extraction methods can be devised.

  9. Characterization of eleutheroside B metabolites derived from an extract of Acanthopanax senticosus Harms by high-resolution liquid chromatography/quadrupole time-of-flight mass spectrometry and automated data analysis.

    Science.gov (United States)

    Lu, Fang; Sun, Qiang; Bai, Yun; Bao, Shunru; Li, Xuzhao; Yan, Guangli; Liu, Shumin

    2012-10-01

    We elucidated the structure and metabolite profile of eleutheroside B, a component derived from the extract of Acanthopanax senticosus Harms, after oral administration of the extract in rats. Samples of rat plasma were collected and analyzed by selective high-resolution liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) automated data analysis method. A total of 11 metabolites were detected: four were identified, and three of those four are reported for the first time here. The three new plasma metabolites were identified on the basis of mass fragmentation patterns and literature reports. The major in vivo metabolic processes associated with eleutheroside B in A. senticosus include demethylation, acetylation, oxidation and glucuronidation after deglycosylation. A fairly comprehensive metabolic pathway was proposed for eleutheroside B. Our results provide a meaningful basis for drug discovery, design and clinical applications related to A. senticosus in traditional Chinese medicine.

  10. Qualitative analysis of a sulfur-fumigated Chinese herbal medicine by comprehensive two-dimensional gas chromatography and high-resolution time of flight mass spectrometry using colorized fuzzy difference data processing.

    Science.gov (United States)

    Cai, Hao; Cao, Gang; Zhang, Hong-Yan

    2017-04-01

    To investigate the chemical transformation of volatile compounds in sulfur-fumigated Radix Angelicae Sinensis. A comprehensive two-dimensional gas chromatography (GC×GC) and high-resolution time-of-flight mass spectrometry (HR-TOF/MS) with colorized fuzzy difference (CFD) method was used to investigate the effect of sulfur-fumigation on the volatile components from Radix Angelicae Sinensis. Twenty-five compounds that were found in sun-dried samples disappeared in sulfur-fumigated samples. Seventeen volatile components including two sulfur-containing compounds were newly generated for the first time in volatile oils of sulfur-fumigated Radix Angelicae Sinensis. The strategy can be successfully applied to rapidly and holistically discriminate sun-dried and sulfur-fumigated Radix Angelicae Sinensis. GC×GC-HR-TOF/MS based CFD is a powerful and feasible approach for the global quality evaluation of Radix Angelicae Sinensis as well as other herbal medicines.

  11. Determination of osteocalcin in meat and bone meal of bovine and porcine origin using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry and high-resolution hybrid mass spectrometry.

    Science.gov (United States)

    Balizs, Gabor; Weise, Christoph; Rozycki, Christel; Opialla, Tobias; Sawada, Stefanie; Zagon, Jutta; Lampen, Alfonso

    2011-05-05

    A method has been developed for determining the origin of meat and bone meal (MBM) by detecting species-specific osteocalcin (OC) using matrix-assisted laser desorption ionization/time-of-flight (MALDI/TOF) and high-resolution hybrid mass spectrometry (HR-Q/TOF MS). The analysis is based on the detection of typical species-specific OC and its tryptic peptide fragments which differ in mass due to differences in the amino-acid sequences between species. After dissolving the MBM samples in EDTA buffer, purification after ultrafiltration was performed using two methods: solid-phase extraction using Zip-Tip C(18) or size exclusion coupled with reverse-phase chromatography. Fractions containing partially purified intact OC were analyzed using LC-Q/TOF and MALDI/TOF mass spectrometry. Species-specific OC was detected at the typical protonated and doubly protonated molecular ions. Furthermore, typical porcine- and bovine-derived tryptic fragments from MBM were detected after enzymatic digestion. In order to determine the underlying amino-acid sequences and to confirm the assignment to OC-derived peptides, MS/MS analysis was carried out. In conclusion, we were able to detect OC in bovine and porcine MBM with high sensitivity and the MS-based method described here by which total OC mass and marker peptides of digested OC are recorded can be used as an alternative approach to detect genus-specific differences in MBM and can be applied as a confirmatory method to mainly immunological osteocalcin screening methods.

  12. Determination of osteocalcin in meat and bone meal of bovine and porcine origin using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry and high-resolution hybrid mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Balizs, Gabor, E-mail: gabor.balizs@bfr.bund.de [Federal Institute for Risk Assessment, Thielallee 88-92, D-14195 Berlin (Germany); Weise, Christoph [Freie Universitaet Berlin, Institute for Chemistry and Biochemistry, Thielallee 63, D-14195 Berlin (Germany); Rozycki, Christel; Opialla, Tobias; Sawada, Stefanie; Zagon, Jutta; Lampen, Alfonso [Federal Institute for Risk Assessment, Thielallee 88-92, D-14195 Berlin (Germany)

    2011-05-05

    A method has been developed for determining the origin of meat and bone meal (MBM) by detecting species-specific osteocalcin (OC) using matrix-assisted laser desorption ionization/time-of-flight (MALDI/TOF) and high-resolution hybrid mass spectrometry (HR-Q/TOF MS). The analysis is based on the detection of typical species-specific OC and its tryptic peptide fragments which differ in mass due to differences in the amino-acid sequences between species. After dissolving the MBM samples in EDTA buffer, purification after ultrafiltration was performed using two methods: solid-phase extraction using Zip-Tip C{sub 18} or size exclusion coupled with reverse-phase chromatography. Fractions containing partially purified intact OC were analyzed using LC-Q/TOF and MALDI/TOF mass spectrometry. Species-specific OC was detected at the typical protonated and doubly protonated molecular ions. Furthermore, typical porcine- and bovine-derived tryptic fragments from MBM were detected after enzymatic digestion. In order to determine the underlying amino-acid sequences and to confirm the assignment to OC-derived peptides, MS/MS analysis was carried out. In conclusion, we were able to detect OC in bovine and porcine MBM with high sensitivity and the MS-based method described here by which total OC mass and marker peptides of digested OC are recorded can be used as an alternative approach to detect genus-specific differences in MBM and can be applied as a confirmatory method to mainly immunological osteocalcin screening methods.

  13. Chemical characterization of particle emissions from controlled burns of biomass fuels using a high resolution time-of-flight aerosol mass spectrometer

    Science.gov (United States)

    Qi, L.; Hosseini, S.; Jung, H.; Yokelson, B.; Weise, D.; Cocker, D., III; Huang, Y.

    2012-03-01

    A total of forty-nine burns were conducted at the Missoula Fire Sciences Lab consisting of nine fuel types; i.e., chamise scrub oak, ceanothus, maritime chaparral, coastal sage scrub, California sage brush, Manzanita, oak savanna, oak woodland and masticated mesquite. This paper focuses on the chemical characterization of fine particle emissions collected for flaming, mixed and smoldering phases using a HR ToF-AMS. The evolution of OM/OC, H/C, O/C and N/C from fire ignition to extinction was measured to capture the transient and integrated chemical composition of the non-refractory portion of bulk particles. Real time elemental ratios and empirical formulas derived with respect to modified combustion efficiency (MCE) are reported. For each fuel, the hydrogen fragment ions dominate the unit mass resolution (UMR) mass spectra with no specific fragment ions attributable to an individual ecological combination. An interference ion in the UMR m/z 73, a fragment normally attributed to levoglucosan, is noted. Therefore, the results imply that C2H4O2+ (m/z 60.021) plus C3H5O2+ (m/z 73.029) are more sufficient to estimate the contribution of levoglucosan. The results did not show significant variations of levoglucosan content in the organic particle with the overall average contribution fraction ranging from 0.74% for coastal sage to 1.93% for chamise.

  14. Chemical characterization of particle emissions from controlled burns of biomass fuels using a high resolution time-of-flight aerosol mass spectrometer

    Directory of Open Access Journals (Sweden)

    L. Qi

    2012-03-01

    Full Text Available A total of forty-nine burns were conducted at the Missoula Fire Sciences Lab consisting of nine fuel types; i.e., chamise scrub oak, ceanothus, maritime chaparral, coastal sage scrub, California sage brush, Manzanita, oak savanna, oak woodland and masticated mesquite. This paper focuses on the chemical characterization of fine particle emissions collected for flaming, mixed and smoldering phases using a HR ToF-AMS. The evolution of OM/OC, H/C, O/C and N/C from fire ignition to extinction was measured to capture the transient and integrated chemical composition of the non-refractory portion of bulk particles. Real time elemental ratios and empirical formulas derived with respect to modified combustion efficiency (MCE are reported. For each fuel, the hydrogen fragment ions dominate the unit mass resolution (UMR mass spectra with no specific fragment ions attributable to an individual ecological combination. An interference ion in the UMR m/z 73, a fragment normally attributed to levoglucosan, is noted. Therefore, the results imply that C2H4O2+ (m/z 60.021 plus C3H5O2+ (m/z 73.029 are more sufficient to estimate the contribution of levoglucosan. The results did not show significant variations of levoglucosan content in the organic particle with the overall average contribution fraction ranging from 0.74% for coastal sage to 1.93% for chamise.

  15. Retrospective analysis by data processing tools for comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry: a challenge for matrix-rich sediment core sample from Tokyo Bay.

    Science.gov (United States)

    Zushi, Yasuyuki; Hashimoto, Shunji; Tamada, Masafumi; Masunaga, Shigeki; Kanai, Yutaka; Tanabe, Kiyoshi

    2014-04-18

    Data processing tools for non-target analysis using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRTOFMS) were developed and applied to a sediment core in Tokyo Bay, focusing on chlorinated compounds in this study. The processing tools were classified in two different methods: (1) the consecutive use of mass defect filter followed by artificial neutral loss scan (MDF/artificial NLS) as a qualitative non-target screening method and (2) Entire Domain Combined Spectra Extraction and Integration Program (ComSpec) and two-dimensional peak sentinel (T-SEN) as a semi-quantitative target screening method. MDF/artificial NLS as a non-target screening approach revealed that PCBs, followed by octachlorodibenzo dioxin (OCDD), were the main chlorinated compounds present in all sediment layers. Furthermore, unknown peaks thought to be chlorinated compounds were found in increasing numbers, some in increasing amounts. T-SEN and ComSpec as a target screening approach were adapted for automatic semi-quantitative analysis showed that, in decreasing concentration order, PCBs, OCDD, and dichlorodiphenyltrichloroethane and its metabolites (DDEs, DDDs) were the main chlorinated pollutants in the sediments. The complementary use of both techniques allows us to extract significant chlorinated pollutants, including non-targeted compounds. This retrospective analysis by this approach performed well even on matrix-rich sediment samples and provided us an interesting insight of historical trends of pollution in Tokyo Bay.

  16. Characterization of the organic contamination pattern of a hyper-saline ecosystem by rapid screening using gas chromatography coupled to high-resolution time-of-flight mass spectrometry.

    Science.gov (United States)

    Serrano, Roque; Portolés, Tania; Blanes, Miguel A; Hernández, Félix; Navarro, Juan C; Varó, Inmaculada; Amat, Francisco

    2012-09-01

    In this paper, gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF MS) has been applied to evaluate organic pollution in a hyper-saline aquatic environment. Firstly, a target screening was made for a list of 150 GC-amenable organic micro-contaminants, including PAHs, octyl/nonyl phenols, PCBs, PBDEs, and a notable number of pesticides, such us insecticides (organochlorines, organophosphorus, carbamates and pyrethroids), herbicides (triazines and chloroacetanilides), fungicides and several transformation products. This methodology was applied to brine samples, with a salt content from 112 g/L to saturation, and to samples from Artemia populations (crustacean Anostraca) collected during 1 year from three sampling stations in saltworks bodies sited in the Ebro river delta. Around 50 target contaminants, belong to chemical families included in the list of priority substances within the framework on European water policy. Additionally, a non-target analysis was performed in both types of samples with the objective of investigating the presence of other non-selected organic compounds taking advantage of the potential of GC-TOF MS (high sensitivity in full-spectrum acquisition mode, accurate mass measurements) for searching unknowns. Organophosphorus pesticides were the contaminants more frequently detected in brine samples. Other compounds usually present in urban and industrial wastewaters, like caffeine, methylparaben, butylated-hydroxytoluene and N-butylbenzenesulfonamide were also detected in brines. The herbicide simazine and the insecticide chlorpyrifos were among the contaminants detected in Artemia samples. Results of this work reveal a potential threat to vulnerable populations inhabiting the hyper-saline ecosystem. The valuable contribution of GC-TOF MS in environmental analysis, allowing the rapid screening of a large number of organic contaminants, is also demonstrated in this paper.

  17. Novel analytical methods for flame retardants and plasticizers based on gas chromatography, comprehensive two-dimensional gas chromatography, and direct probe coupled to atmospheric pressure chemical ionization-high resolution time-of-flight-mass spectrometry.

    Science.gov (United States)

    Ballesteros-Gómez, Ana; de Boer, Jacob; Leonards, Pim E G

    2013-10-15

    In this study, we assess the applicability of different analytical techniques, namely, direct probe (DP), gas chromatography (GC), and comprehensive two-dimensional gas chromatography (GC × GC) coupled to atmospheric pressure chemical ionization (APCI) with a high resolution (HR)-time-of-flight (TOF)-mass spectrometry (MS) for the analysis of flame retardants and plasticizers in electronic waste and car interiors. APCI-HRTOFMS is a combination scarcely exploited yet with GC or with a direct probe for screening purposes and to the best of our knowledge, never with GC × GC to provide comprehensive information. Because of the increasing number of flame retardants and questions about their environmental fate, there is a need for the development of wider target and untargeted screening techniques to assess human exposure to these compounds. With the use of the APCI source, we took the advantage of using a soft ionization technique that provides mainly molecular ions, in addition to the accuracy of HRMS for identification. The direct probe provided a very easy and inexpensive method for the identification of flame retardants without any sample preparation. This technique seems extremely useful for the screening of solid materials such as electrical devices, electronics and other waste. GC-APCI-HRTOF-MS appeared to be more sensitive compared to liquid chromatography (LC)-APCI/atmospheric pressure photoionization (APPI)-HRTOF-MS for a wider range of flame retardants with absolute detection limits in the range of 0.5-25 pg. A variety of tri- to decabromodiphenyl ethers, phosphorus flame retardants and new flame retardants were found in the samples at levels from microgram per gram to milligram per gram levels.

  18. A high-resolution time-of-flight chemical ionization mass spectrometer utilizing hydronium ions (H3O+ ToF-CIMS) for measurements of volatile organic compounds in the atmosphere

    Science.gov (United States)

    Yuan, Bin; Koss, Abigail; Warneke, Carsten; Gilman, Jessica B.; Lerner, Brian M.; Stark, Harald; de Gouw, Joost A.

    2016-07-01

    Proton transfer reactions between hydronium ions (H3O+) and volatile organic compounds (VOCs) provide a fast and highly sensitive technique for VOC measurements, leading to extensive use of proton-transfer-reaction mass spectrometry (PTR-MS) in atmospheric research. Based on the same ionization approach, we describe the development of a high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) utilizing H3O+ as the reagent ion. The new H3O+ ToF-CIMS has sensitivities of 100-1000 cps ppb-1 (ion counts per second per part-per-billion mixing ratio of VOC) and detection limits of 20-600 ppt at 3σ for a 1 s integration time for simultaneous measurements of many VOC species of atmospheric relevance. The ToF analyzer with mass resolution (m/Δm) of up to 6000 allows the separation of isobaric masses, as shown in previous studies using similar ToF-MS. While radio frequency (RF)-only quadrupole ion guides provide better overall ion transmission than ion lens system, low-mass cutoff of RF-only quadrupole causes H3O+ ions to be transmitted less efficiently than heavier masses, which leads to unusual humidity dependence of reagent ions and difficulty obtaining a humidity-independent parameter for normalization. The humidity dependence of the instrument was characterized for various VOC species and the behaviors for different species can be explained by compound-specific properties that affect the ion chemistry (e.g., proton affinity and dipole moment). The new H3O+ ToF-CIMS was successfully deployed on the NOAA WP-3D research aircraft for the SONGNEX campaign in spring of 2015. The measured mixing ratios of several aromatics from the H3O+ ToF-CIMS agreed within ±10 % with independent gas chromatography measurements from whole air samples. Initial results from the SONGNEX measurements demonstrate that the H3O+ ToF-CIMS data set will be valuable for the identification and characterization of emissions from various sources, investigation of secondary

  19. Miniaturised Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Rohner, U.; Benz, W.; Whitby, J. A.; Wurz, P.; Schulz, R.; Romstedt, J.

    2004-04-01

    Originally intended for the European Space Agency's BepiColombo mission to Mercury, we have built a series of highly miniaturised laser ablation time of flight mass spectrometers (LMS), suitable for in situ measurements of the elemental and isotopic composition of the surface of airless planetary bodies. The instruments will determine ma jor, minor, and trace element abundances in minerals on a spatial scale of 10 m, and will have sufficient dynamic range and mass resolution to perform useful isotopic measurements in favourable cases. Solid material is simultaneously evaporated and ionised by means of laser ablation, requiring intense pulsed laser radiation. Laser ablation was chosen as the sample introduction technique principally because of its high spatial resolution and the lack of any need for sample preparation. Advantages of the technique include simplicity of the resulting design, speed of measurement, and the ability for depth profiling (potentially important for a regolith in which mineral grains are coated with impact produced glass). Time of flight mass spectrometers are simple, robust devices that couple well to a pulsed ion source and we have previous experience of their construction for space flight, e.g. the ROSINA instrument suite for the ROSETTA mission. For BepiColombo, we have built two prototype instruments, one with a design mass of 500 g and a volume comparable to a beer can intended to be deployed on a static lander, and a smaller cigarettebox sized version with a design mass of 250 g, small enough to be integrated in a rover or robotic arm.

  20. Development of a new corona discharge based ion source for high resolution time-of-flight chemical ionization mass spectrometer to measure gaseous H2SO4 and aerosol sulfate

    Science.gov (United States)

    Zheng, Jun; Yang, Dongsen; Ma, Yan; Chen, Mindong; Cheng, Jin; Li, Shizheng; Wang, Ming

    2015-10-01

    A new corona discharge (CD) based ion source was developed for a commercial high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) (Aerodyne Research Inc.) to measure both gaseous sulfuric acid (H2SO4) and aerosol sulfate after thermal desorption. Nitrate core ions (NO3-) were used as reagent ions and were generated by a negative discharge in zero air followed by addition of excess nitrogen dioxide (NO2) to convert primary ions and hydroxyl radicals (OH) into NO3- ions and nitric acid (HNO3). The CD-HRToF-CIMS showed no detectable interference from hundreds parts per billion by volume (ppbv) of sulfur dioxide (SO2). Unlike the atmospheric pressure ionization (API) ToF-CIMS, the CD ion source was integrated onto the ion-molecule reaction (IMR) chamber and which made it possible to measure aerosol sulfate by coupling to a filter inlet for gases and aerosols (FIGAERO). Moreover, compared with a quadrupole-based mass spectrometer, the desired HSO4- signal was detected by its exact mass of m/z 96.960, which was well resolved from the potential interferences of HCO3-ṡ(H2O)2 (m/z 97.014) and O-ṡH2OṡHNO3 (m/z 97.002). In this work, using laboratory-generated standards the CD-HRToF-CIMS was demonstrated to be able to detect as low as 3.1 × 105 molecules cm-3 gaseous H2SO4 and 0.5 μg m-3 ammonium sulfate based on 10-s integration time and two times of the baseline noise. The CD ion source had the advantages of low cost and a simple but robust structure. Since the system was non-radioactive and did not require corrosive HNO3 gas, it can be readily field deployed. The CD-HRToF-CIMS can be a powerful tool for both field and laboratory studies of aerosol formation mechanism and the chemical processes that were critical to understand the evolution of aerosols in the atmosphere.

  1. Evaluating the degree of oxygenation of organic aerosol during foggy and hazy days in Hong Kong using high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS

    Directory of Open Access Journals (Sweden)

    Y. J. Li

    2013-02-01

    Full Text Available The chemical characteristics of organic aerosol (OA are still poorly constrained. Here we present observation results of the degree of oxygenation of OA based on high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS measurements made at a coastal site in Hong Kong from late April to the end of May in 2011. Two foggy periods and one hazy period were chosen for detailed analysis to compare the changes in the degree of oxygenation of OA due to different processes. The Extended Aerosol Inorganic Model (E-AIM predicted a fine particle liquid water content (LWCfp up to 85 μg m−3 during the foggy days. Particle concentration as measured by HR-ToF-AMS was up to 60 μg m−3 during the hazy days and up to 30 μg m−3 during the foggy days. The degree of oxygenation of OA, as indicated by several parameters including the fraction of m/z 44 in organic mass spectra (f44, the elemental ratio of oxygen to carbon (O : C, and the carbon oxidation state (OSc, was evaluated against the odd oxygen (Ox concentration, LWCfp, ionic strength (IS, and in-situ pH (pHis. Results suggest that the high concentration of OA (on average 11 μg m−3 and the high degree of oxygenation (f44 = 0.15, O : C = 0.51, and OSc = −0.31 during the hazy period were mainly due to gas-phase oxidation. During the foggy periods with low photochemical activities, the degree of oxygenation of OA was almost as high as that on the hazy days and significantly higher than that during non-foggy/non-hazy days. However, the OA evolved quite differently in the two foggy periods. The first foggy period in late April saw a larger LWCfp and a lower Ox concentration and the OA was made up of ~ 20% semi

  2. Ultra high performance liquid chromatography-time-of-flight high resolution mass spectrometry in the analysis of hexabromocyclododecane diastereomers: method development and comparative evaluation versus ultra high performance liquid chromatography coupled to Orbitrap high resolution mass spectrometry and triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Zacs, D; Rjabova, J; Pugajeva, I; Nakurte, I; Viksna, A; Bartkevics, V

    2014-10-31

    An efficient ultra high performance liquid chromatography (UHPLC)-time-of-flight high resolution mass spectrometry (TOF-HRMS) method was elaborated for the determination of hexabromocyclododecane (HBCD) diastereomers in fish samples and compared against UHPLC-Orbitrap-HRMS and UHPLC-triple quadrupole (QqQ) tandem MS (MS/MS) techniques. The TOF-HRMS analyzer was operated at high resolution (>10000 full width at half maximum (FWHM)) with scanning the m/z range from 600 to 700, to achieve picogram quantitation limits. The effects of various operational parameters on the instrumental response were systematically investigated. Evaluation of the influence of sample clean-up procedure steps on signal suppression effect including removal of the matrix components by means of destructive acidic treatment or non-destructive gel permeation chromatography (GPC), and additional Florisil column chromatography step showed that the analytical response of UHPLC-TOF-HRMS system is much more affected by the presence of matrix components in the final extracts in comparison with UHPLC-Orbitrap-HRMS and UHPLC-QqQ-MS/MS systems. The method was robustly validated and used for the analysis of eel (Anquilla anquilla) samples originating from a Latvian lake. UHPLC-TOF-HRMS showed a suitable performance under the optimized conditions: recoveries for three selected diastereomers in the range of 99-116%; repeatability and intermediate precision expressed as relative standard deviation (RSD) in the ranges of 2.3-7.1% and 2.9-8.1%, respectively. The elaborated method achieved instrumental limits of quantification (i-LOQ) of 0.9-4.5pg on column that were suitable for the trace analysis of three HBCD diastereomers, corresponding to the method limits of quantification (m-LOQ) of 7.0-29pgg(-1) wet weight (w.w.). The efficiency of UHPLC-TOF-HRMS method was evaluated by comparing the performance characteristics and analytical data from real samples with the validation data and real sample results

  3. An integrated strategy for rapid and accurate determination of free and cell-bound microcystins and related peptides in natural blooms by liquid chromatography-electrospray-high resolution mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry using both positive and negative ionization modes.

    Science.gov (United States)

    Flores, Cintia; Caixach, Josep

    2015-08-14

    An integrated high resolution mass spectrometry (HRMS) strategy has been developed for rapid and accurate determination of free and cell-bound microcystins (MCs) and related peptides in water blooms. The natural samples (water and algae) were filtered for independent analysis of aqueous and sestonic fractions. These fractions were analyzed by MALDI-TOF/TOF-MS and ESI-Orbitrap-HCD-MS. MALDI, ESI and the study of fragmentation sequences have been provided crucial structural information. The potential of combined positive and negative ionization modes, full scan and fragmentation acquisition modes (TOF/TOF and HCD) by HRMS and high resolution and accurate mass was investigated in order to allow unequivocal determination of MCs. Besides, a reliable quantitation has been possible by HRMS. This composition helped to decrease the probability of false positives and negatives, as alternative to commonly used LC-ESI-MS/MS methods. The analysis was non-target, therefore covered the possibility to analyze all MC analogs concurrently without any pre-selection of target MC. Furthermore, archived data was subjected to retrospective "post-targeted" analysis and a screening of other potential toxins and related peptides as anabaenopeptins in the samples was done. Finally, the MS protocol and identification tools suggested were applied to the analysis of characteristic water blooms from Spanish reservoirs.

  4. Quadrupole Time-of-Flight Mass Spectrometer

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: The system generates superior quality mass spectrometry (MS) and tandem mass spectrometry (MS/MS) data from both atmospheric pressure ionization (API) and...

  5. High-Resolution Mass Spectrometers

    Science.gov (United States)

    Marshall, Alan G.; Hendrickson, Christopher L.

    2008-07-01

    Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

  6. Time-of-Flight Mass Measurements of Neutron Rich Nuclides

    Science.gov (United States)

    Estrade, A.; Matos, M.; Amthor, A. M.; Becerril, A.; Elliot, T.; Lorusso, G.; Rogers, A.; Schatz, H.; Bazin, D.; Gade, A.; Portillo, M.; Stolz, A.; Galaviz, D.; Pereira, J.; Shapira, D.; Smith, E.; Wallace, M.

    2008-10-01

    Nuclear masses of neutron rich isotopes in the region of Z ˜ 20-30 have been measured using the time-of-flight technique at the National Superconducting Cyclotron Laboratory (NSCL). The masses of 5 isotopes have been measured for the first time, and the precision of several other masses has been improved. The time-of-flight technique has shown the potential to access nuclear masses very far from stability when applied at radioactive beam facilities like the NSCL. Such measurements are important for understanding nuclear structure far from the valley of β-stability, and provide valuable information for astrophysical model calculations of processes involving very unstable nuclides.

  7. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosev, Krasimir Milchev

    2007-07-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  8. Development of a high resolution laser based angle-resolving time-of-flight photoelectron spectrometer

    CERN Document Server

    Berntsen, M H; Tjernberg, O

    2011-01-01

    We present the design and performance of a novel Laser-based Angle-Resolving Time-of-Flight (LARTOF) system for photoemission from solids in the vacuum ultraviolet (VUV) energy range. A pulsed laser provides photons which through a third harmonic generation (THG) process performed in a xenon filled gas cell generates VUV photons of energy 10.5 eV. The time-of-flight analyzer is able to collect all electrons that are emitted from the sample within a circular cone of up to +/-15 degrees. By simultaneously measuring the energy and emission angle along two spatial directions for the electrons the analyzer provides three-dimensional detection capability. Data from a test measurement performed on the Au(111) surface state is presented along with some more advanced measurements of the Fermi surface of the high-temperature superconductor Bi2212.

  9. A magnetic-free high-resolution parabolic mirror time-of-flight electron energy spectrometer

    Institute of Scientific and Technical Information of China (English)

    张戈; 沈鸿元; 曾瑞荣; 黄呈辉; 林文雄; 黄见洪

    2001-01-01

    The principle and structure of a magnetic-free high-resolution high-efficiency parabolic mirror time-offligght electron energy spectrometer are presented. The electron energy spectrum of Nz in a flight tube is measured using a 105 fs Ti:sappbire laser under different gas pressures.

  10. Wide-band mass measurements with a multi-reflection time-of-flight mass spectrograph

    CERN Document Server

    Schury, P; Wada, M; Wollnik, H

    2013-01-01

    We characterize the mass bandwidth of the a multi-reflection time-of-flight mass spectrograph, showing both the functional and useful mass bandwidth. We then demonstrate the use of a multi-reflection time-of-flight mass spectrograph to perform mass measurements in mass bands much wider than the mass bandwidth.

  11. Dynamic imaging with high resolution time-of-flight pet camera - TOFPET I

    Energy Technology Data Exchange (ETDEWEB)

    Mullani, N.A.; Bristow, D.; Gaeta, J.; Gould, K.L.; Hartz, R.K.; Philipe, E.A.; Wong, W.H.; Yerian, K.

    1984-02-01

    One of the major design goals of the TOFPET I positron camera was to produce a high resolution whole body positron camera capable of dynamically imaging an organ such as the heart. TOFPET I is now nearing completion and preliminary images have been obtained to assess its dynamic and three dimensional imaging capabilities. Multiple gated images of the uptake of Rubidium in the dog heart and three dimensional surface displays of the distribution of the Rubidium-82 in the myocardium have been generated to demonstrate the three dimensional imaging properties. Fast dynamic images of the first pass of a bolus of radio-tracer through the heart have been collected with 4 second integration time and 50% gating (2 second equivalent integration time) with 18 mCi of Rb-82.

  12. Ion trap with integrated time-of-flight mass spectrometer

    CERN Document Server

    Schneider, Christian; Yu, Peter; Hudson, Eric R

    2015-01-01

    Recently, we reported an ion trap experiment with an integrated time-of-flight mass spectrometer (TOFMS) [Phys. Rev. Appl. 2, 034013 (2014)] focussing on the improvement of mass resolution and detection limit due to sample preparation at millikelvin temperatures. The system utilizes a radio-frequency (RF) ion trap with asymmetric drive for storing and manipulating laser-cooled ions and features radial extraction into a compact $275$ mm long TOF drift tube. The mass resolution exceeds $m / \\Delta m = 500$, which provides isotopic resolution over the whole mass range of interest in current experiments and constitutes an improvement of almost an order of magnitude over other implementations. In this manuscript, we discuss the experimental implementation in detail, which is comprised of newly developed drive electronics for generating the required voltages to operate RF trap and TOFMS, as well as control electronics for regulating RF outputs and synchronizing the TOFMS extraction.

  13. Avalanche photodiode based time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Keiichi, E-mail: kogasawara@swri.edu; Livi, Stefano A.; Desai, Mihir I.; Ebert, Robert W.; McComas, David J.; Walther, Brandon C. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States)

    2015-08-15

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  14. Avalanche photodiode based time-of-flight mass spectrometry.

    Science.gov (United States)

    Ogasawara, Keiichi; Livi, Stefano A; Desai, Mihir I; Ebert, Robert W; McComas, David J; Walther, Brandon C

    2015-08-01

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1-40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  15. Proton Transfer Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Thomas B [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Proton Transfer Reaction Mass Spectrometer (PTRMS) measures gas-phase compounds in ambient air and headspace samples before using chemical ionization to produce positively charged molecules, which are detected with a time-of-flight (TOF) mass spectrometer. This ionization method uses a gentle proton transfer reaction method between the molecule of interest and protonated water, or hydronium ion (H3O+), to produce limited fragmentation of the parent molecule. The ions produced are primarily positively charged with the mass of the parent ion, plus an additional proton. Ion concentration is determined by adding the number of ions counted at the molecular ion’s mass-to-charge ratio to the number of air molecules in the reaction chamber, which can be identified according to the pressure levels in the reaction chamber. The PTRMS allows many volatile organic compounds in ambient air to be detected at levels from 10–100 parts per trillion by volume (pptv). The response time is 1 to 10 seconds.

  16. LVGEMS Time-of-Flight Mass Spectrometry on Satellites

    Science.gov (United States)

    Herrero, Federico

    2013-01-01

    NASA fs investigations of the upper atmosphere and ionosphere require measurements of composition of the neutral air and ions. NASA is able to undertake these observations, but the instruments currently in use have their limitations. NASA has extended the scope of its research in the atmosphere and now requires more measurements covering more of the atmosphere. Out of this need, NASA developed multipoint measurements using miniaturized satellites, also called nanosatellites (e.g., CubeSats), that require a new generation of spectrometers that can fit into a 4 4 in. (.10 10 cm) cross-section in the upgraded satellites. Overall, the new mass spectrometer required for the new depth of atmospheric research must fulfill a new level of low-voltage/low-power requirements, smaller size, and less risk of magnetic contamination. The Low-Voltage Gated Electrostatic Mass Spectrometer (LVGEMS) was developed to fulfill these requirements. The LVGEMS offers a new spectrometer that eliminates magnetic field issues associated with magnetic sector mass spectrometers, reduces power, and is about 1/10 the size of previous instruments. LVGEMS employs the time of flight (TOF) technique in the GEMS mass spectrometer previously developed. However, like any TOF mass spectrometer, GEMS requires a rectangular waveform of large voltage amplitude, exceeding 100 V -- that means that the voltage applied to one of the GEMS electrodes has to change from 0 to 100 V in a time of only a few nanoseconds. Such electronic speed requires more power than can be provided in a CubeSat. In the LVGEMS, the amplitude of the rectangular waveform is reduced to about 1 V, compatible with digital electronics supplies and requiring little power.

  17. High Throughput Screening of Tranquilizers in Dairy Products Using Ultra Performance Liquid Chromatography Coupled to High Resolution Time-of-Flight Mass Spectrometry%超高效液相色谱-飞行时间质谱法高通量筛查乳制品中20种镇静剂

    Institute of Scientific and Technical Information of China (English)

    严丽娟; 张洁; 潘晨松; 林立毅; 张欣怡; 申河清

    2013-01-01

    A high throughput screening method was developed for the simultaneous determination of twenty representative tranquilizers in dairy products using the combination of ultra-performance liquid chromatography -high resolution time-of-flight mass spectrometry and screening database built with Target Analysis software. The protein and fat in the sample was removed using a two-step precipitation of acetonitrile and acidic acetonitrile, and the supernatant was combined and concentrated with Speedvac concentrator. The chromatographie separation was performed on an ACQUITY BEH column with gradient elutin using 0. 1% formic acid and acetonitrile as mobile phase at a flow rate of 0. 3 mL/min. The monitoring of tranquilizers was achieved by time-of-flight mass spectrometry under positive ionization mode in 9 min. The quantification was performed with matrix-matching method. The linear ranges were 1-500 μg/L or 5-1000 μg/L. The LODs and LOQs were 0.3-1.5 μg/L and 1-5 μg/L, respectively. At 5 and 50 μg/L spiked levels, the average recoveries were 76. l%-108.2% with relative standard deviations of 2.5%-9.0%. The screening result for spiked sample showed all the spiked tranquilizers could be correctly identified with low deviations of retention time ( 89. 5%). The developed method was further applied for the analysis of 50 real dairy products, and no positive sample was detected.%利用超高效液相色谱/高分辨飞行时间质谱,结合数据库,建立了乳制品中20种镇静剂的高通量筛查方法.样品以乙腈和酸化乙腈沉淀蛋白质和脂肪,冷冻离心浓缩,经超高效液相色谱分离,采用电喷雾离子源,正离子模式,基质匹配法进行定量分析,可在9 min内对20种镇静剂进行高通量筛查和定量分析.镇静剂的质量浓度在l~ 500 μg/L或5~1000μg/L范围内具有较好的线性关系,检出限为0.3~1.5μg/L,定量限为1~5 μg/L.在5和50 μg/L添加水平时,平均回收率为76.1% ~ 108.2

  18. High resolution pulsed field ionization photoelectron spectroscopy using multibunch synchrotron radiation: Time-of-flight selection scheme

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, G.K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Song, Y.; Ng, C.Y. [Ames Laboratory, United States Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)

    1999-06-01

    We have developed an efficient electron time-of-flight (TOF) selection scheme for high resolution pulsed field ionization (PFI) photoelectron (PFI-PE) measurements using monochromatized multibunch undulator synchrotron radiation at the Advanced Light Source. By employing a simple electron TOF spectrometer, we show that PFI-PEs produced by the PFI in the dark gap of a synchrotron ring period can be cleanly separated from prompt background photoelectrons. A near complete suppression of prompt electrons was achieved in PFI-PE measurements by gating the PFI-PE TOF peak, as indicated by monitoring background electron counts at the Ar(11s{sup {prime}}) autoionizing Rydberg peak, which is adjacent to the Ar{sup +}({sup 2}P{sub 3/2}) PFI-PE band. The rotational-resolved PFI-PE band for H{sub 2}{sup +} (X {sup 2}{Sigma}{sub g}{sup +},v{sup +}=0) measured using this electron TOF selection scheme is nearly free from residues of nearby autoionizing features, which were observed in the previous measurement by employing an electron spectrometer equipped with a hemispherical energy analyzer. This comparison indicates that the TOF PFI-PE scheme is significantly more effective in suppressing the hot-electron background. In addition to attaining a high PFI-PE transmission, a major advantage of the electron TOF scheme is that it allows the use of a smaller pulsed electric field and thus results in a higher instrumental PFI-PE resolution. We have demonstrated instrumental resolutions of 1.0 cm{sup {minus}1} full width at half maximum (FWHM) and 1.9 cm{sup {minus}1} FWHM in the PFI-PE bands for Xe{sup +}({sup 2}P{sub 3/2}) and Ar{sup +}({sup 2}P{sub 3/2}) at 12.123 and 15.760 eV, respectively. These resolutions are more than a factor 2 better than those achieved in previous synchrotron based PFI-PE studies. {copyright} {ital 1999 American Institute of Physics.}

  19. The Impact II, a Very High-Resolution Quadrupole Time-of-Flight Instrument (QTOF) for Deep Shotgun Proteomics.

    Science.gov (United States)

    Beck, Scarlet; Michalski, Annette; Raether, Oliver; Lubeck, Markus; Kaspar, Stephanie; Goedecke, Niels; Baessmann, Carsten; Hornburg, Daniel; Meier, Florian; Paron, Igor; Kulak, Nils A; Cox, Juergen; Mann, Matthias

    2015-07-01

    Hybrid quadrupole time-of-flight (QTOF) mass spectrometry is one of the two major principles used in proteomics. Although based on simple fundamentals, it has over the last decades greatly evolved in terms of achievable resolution, mass accuracy, and dynamic range. The Bruker impact platform of QTOF instruments takes advantage of these developments and here we develop and evaluate the impact II for shotgun proteomics applications. Adaption of our heated liquid chromatography system achieved very narrow peptide elution peaks. The impact II is equipped with a new collision cell with both axial and radial ion ejection, more than doubling ion extraction at high tandem MS frequencies. The new reflectron and detector improve resolving power compared with the previous model up to 80%, i.e. to 40,000 at m/z 1222. We analyzed the ion current from the inlet capillary and found very high transmission (>80%) up to the collision cell. Simulation and measurement indicated 60% transfer into the flight tube. We adapted MaxQuant for QTOF data, improving absolute average mass deviations to better than 1.45 ppm. More than 4800 proteins can be identified in a single run of HeLa digest in a 90 min gradient. The workflow achieved high technical reproducibility (R2 > 0.99) and accurate fold change determination in spike-in experiments in complex mixtures. Using label-free quantification we rapidly quantified haploid against diploid yeast and characterized overall proteome differences in mouse cell lines originating from different tissues. Finally, after high pH reversed-phase fractionation we identified 9515 proteins in a triplicate measurement of HeLa peptide mixture and 11,257 proteins in single measurements of cerebellum-the highest proteome coverage reported with a QTOF instrument so far.

  20. 超高效液相色谱/高分辨飞行时间质谱法同时检测乳制品中19种抗生素%Simultaneous analysis of 19 antibiotics in dairy products using ultra-performance liquid chromatography coupled with high resolution time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张洁; 严丽娟; 潘晨松; 林立毅; 张欣怡; 申河清

    2012-01-01

    An ultra-performance liquid chromatography coupled with high resolution time-of-flight mass spectrometry method (UPLC/HRTOF-MS) has been developed for the simultaneous analysis of 19 antibiotics in dairy products. The sample was treated with acetonitrile and acidic acetonitrile to remove protein and fat, and then the supernatant was concentrated with a concentrator system. The antibiotics in the prepared sample were separated on a BEH column, and then qualitatively and quantitatively analyzed by HRTOF-MS in positive ionization mode within 10 min. A screening database containing the qualitative information of the antibiotics was built with TargetAnalysis software. Matrix matching was used in the antibiotic analysis to compensate for the matrix effects that influence analytical response. The linear range of the antibiotics was 10 -500 or 15 - 1 000 μg/L. The limits of detection (LOD) were from 3 to 5 μg/L. At the spiked levels of 20 and 100 μg/L, the average recoveries were from 68. 4% to 96. 7% with the relative standard deviations ranging from 2. 1% to 12. 5%. The screening results of a spiked milk sample showed that all the spiked antibiotics could be detected with their deviations of retention time ≤0. 1 min, the deviations of mass <5 mDa, the degrees of isotope pattern match ≥ 87.4%, and most spiked antibiotics were detected with high scores. Furthermore, the devel- oped method was applied for the analysis of antibiotics in more than 40 milk and dairy products of seven manufacturers, and the target antibiotics were not detected in all the samples. The method is rapid, sensitive and easy to operate, and is suitable for the screening of antibiotic residues in milk and dairy products.%利用超高效液相色谱/高分辨飞行时间质谱结合数据库建立了乳制品中19种抗生素的分析方法.样品依次经过乙腈和酸化乙腈处理后,冷冻离心浓缩,经超高效液相色谱分离,正离子扫描模式下,在10 min内对19种抗生素进

  1. Application of time-of-flight secondary ion mass spectrometry to automobile paint analysis.

    Science.gov (United States)

    Lee, Y; Han, S; Yoon, J H; Kim, Y M; Shon, S K; Park, S W

    2001-06-01

    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides a method of elemental analysis that can distinguish among automotive paint samples of the same or nearly the same color. TOF-SIMS survey spectra were employed to determine the relative abundances of elements in the surface layers of the paint chips. The depth profile of paint samples permitted the analysis of small paint chips, the reproducible results for specific elements, and the identification of each car paint. Seventy-three samples of blue, red, white, and silver automobile paints from the major manufacturers in Korea were investigated using high resolution TOF-SIMS technique. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. TOF-SIMS is a reliable, nondestructive, and small area analyzing method for characterization of the elemental composition of automotive paint chips.

  2. High-throughput shotgun lipidomics by quadrupole time-of-flight mass spectrometry

    DEFF Research Database (Denmark)

    Ståhlman, Marcus; Ejsing, Christer S.; Tarasov, Kirill;

    2009-01-01

    Technological advances in mass spectrometry and meticulous method development have produced several shotgun lipidomic approaches capable of characterizing lipid species by direct analysis of total lipid extracts. Shotgun lipidomics by hybrid quadrupole time-of-flight mass spectrometry allows...

  3. Rapid screening of 10 drugs in blood using ultra performance liquid chromatography with high resolution quadrupole-time-of-flight mass spectrometry%超高效液相色谱-四极杆-飞行时间质谱法快速筛查血液中10种常见毒物

    Institute of Scientific and Technical Information of China (English)

    石银涛; 王绘军; 郭璟琦; 丁静; 王俊伟

    2016-01-01

    A high-throughput method was developed for rapid screening of 10 drugs in blood by ultra performance liquid chromatography with high resolution quadrupole-time-of-flight mass spectrometry( UPLC-Q-TOF/MS). The sample was extracted by ethyl acetate,the extraction solution was concentrated to near dryness,and dissolved with methanol. Then the sample was passed through a 0. 22 μm membrane. The separation of the 10 target compounds was per-formed on a Waters ACQUITY UPLC@BEH C18 column(100 mm×2. 1 mm,1. 7 μm)with gra-dient elution using methanol and 0. 1%( v/v)formic acid aqueous solution as mobile phases, and analyzed by UPLC-Q-TOF/MS under electrospray ionization ( ESI ) mode with scanning range of m/z 50-1 000. Rapid screening can be achieved using MS matching scores,deviation of retention time,measured mass,isotopic abundance matching scores,isotope spacing match scores and MS/MS matching scores. Good linearities were observed in the range of 10. 0-500. 0μg/L with the correlation coefficients from 0. 990 8 to 0. 995 8. The limits of detection and the limits of quantification were 1. 0-2. 0 μg/L and 4. 0-8. 0 μg/L,respectively. The spiked recov-eries were 56. 7% -83. 0% with the relative standard deviations of 3. 6% -8. 9%. The result screening database was built using Agilent Mass Hunter PCDL Manager software and then used for the analysis of spiked samples. MS matching scores,isotopic abundance matching scores, isotope spacing matching scores(all > 90 points)and MS/MS matching scores(> 70 points) were applied to identify the drugs. The results showed that all the spiked drugs could be cor-rectly identified with low deviations of retention time(< 0. 1 min)and mass(< 1 mDa). The developed method is suitable for the screening and confirmation of the drugs in forensic and clinical analytical toxicology.%建立了超高效液相色谱-四极杆-飞行时间串联质谱( UPLC-Q-TOF/MS)快速筛查血液中10种毒物的检测方法。用乙酸乙酯提取

  4. A new Time-of-Flight mass measurement project for exotic nuclei and ultra-high precision detector development

    Directory of Open Access Journals (Sweden)

    Sun Bao-Hua

    2016-01-01

    Full Text Available The time-of-flight (TOF mass spectrometry (MS, a high-resolution magnetic spectrometer equipped with a fast particle tracking system, is well recognized by its ability in weighing the most exotic nuclei. Currently such TOF-MS can achieve a mass resolution power of about 2×10−4. We show that the mass resolution can be further improved by one order of magnitude with augmented timing and position detectors. We report the progress in developing ultra-fast detectors to be used in TOF-MS.

  5. Accurate Mass Determination of Amino Alcohols by Turboionspray/Time-of-Flight Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GENG,Yu(耿昱); GUO,Yin-Long(郭寅龙); ZHAO,Shi-Min(赵士民); MA,Sheng-Ming(麻生明)

    2002-01-01

    Amino alcohols were studied by turboionspray/time-of-flight mass spectrometry (TIS/TOF-MS) with the aim of determining the accurate mass of their protonated molecule ions.Polyethylene glycol (PEG) was used as the internal reference.Compared with the theoretical values, all relative errors were less than 5×10-6. The effects of nozzle potential, nozzle temperature, acquisition rate etc. on accurate mass determination were also studied.

  6. Miniature Time of Flight Mass Spectrometer for Space and Extraterrestrial Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The PI has developed a miniature time-of-flight mass spectrometer (TOF-MS), which can be op-timized for space and extraterrestrial applications, by using a...

  7. Data Collection and Processing Instrumentation for Time-of-Flight Mass Spectrometry and Ion Mobility Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Sysoev, Alexey A.; Fomin, O. I.; Poteshin, S. S.; Chernyshev, D. M.; Karpov, A. V.; Sysoev, Alexander A.

    Data processing characteristics can significantly affect reliability of obtained results. Here we discuss two recently developed data collection instruments based on analog-to-digital converters. The first instrument is based on three 500 MHz 12 bit ADC and used for extended dynamic range measurements. Based on 667 MHz 8 bit ADC the second one allows fast 3D data acquisition. The instruments were used for time-of-flight mass spectrometry and ion mobility TOF mass spectrometry fast data acquisition and processing.

  8. Assessment of a high-resolution candidate detector for prostate time-of-flight positron emission tomography.

    Science.gov (United States)

    Cosentino, Luigi; Finocchiaro, Paolo; Pappalardo, Alfio; Garibaldi, Franco

    2012-11-01

    We report on the measurements performed using a (22)Na source on a detector element for a magnetic resonance imaging-compatible time-of-flight-positron emission tomography endorectal prostate probe, with depth-of-interaction sensitivity. It is made from a LYSO scintillator crystal, wrapped with Lumirror, readout at both ends by means of silicon photomultipliers. With a detailed description of the data analysis procedure, we show that our results point to a 400 ps coincidence resolving time and, at the same time, to a depth-of-interaction resolution of 1 mm. These appealing features, along with the tiny 1.5 mm × 1.5 mm × 10 mm crystal size, are quite promising in view of the realization of a prototype probe.

  9. A high-resolution time-of-flight energy analyzer for femtosecond electron pulses at 30 keV

    Science.gov (United States)

    Gliserin, Alexander; Walbran, Matthew; Baum, Peter

    2016-03-01

    We report a time-of-flight spectrometer for electron pulses at up to 30 keV, which is a suitable energy for atomic-resolution femtosecond investigations via time-resolved electron diffraction, microscopy, and energy loss spectroscopy. For realistic femtosecond beams without apertures, the instrument's energy resolution is ˜0.5 eV (full width at half maximum) or 2 × 10-5 at a throughput of 50%-90%. We demonstrate the analyzer's versatility by three first applications, namely, femtosecond electron pulse metrology via optical streaking, in situ drift correction in laser-microwave synchronization for electron pulse compression, and time-resolved electron energy loss spectroscopy of aluminum, showing the instrument's capability of tracking plasmonic loss peak positions with few-meV accuracy.

  10. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.

    2012-01-01

    response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design...

  11. Linear electric field time-of-flight ion mass spectrometer

    Science.gov (United States)

    Funsten, Herbert O.; Feldman, William C.

    2008-06-10

    A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

  12. Time-of-flight mass spectrometry for explosives trace detection

    Science.gov (United States)

    Pettersson, Anna; Elfving, Anders; Elfsberg, Mattias; Hurtig, Tomas; Johansson, Niklas; Al-Khalili, Ahmed; Käck, Petra; Wallin, Sara; Östmark, Henric

    2012-06-01

    This paper presents the ongoing development of a laser ionization mass spectrometric system to be applied for screening for security related threat substances, specifically explosives. The system will be part of a larger security checkpoint system developed and demonstrated within the FP7 project EFFISEC to aid border police and customs at outer border checks. The laser ionization method of choice is SPI (single photon ionization), but the system also incorporates optional functionalities such as a cold trap and/or a particle concentrator to facilitate detection of minute amounts of explosives. The possibility of using jet-REMPI as a verification means is being scrutinized. Automated functionality and user friendliness is also considered in the demo system development.

  13. High-resolution Time-Of-Flight PET with Depth-Of-Interaction becomes feasible: a proof of principle

    CERN Document Server

    Cosentino, Luigi; Pappalardo, Alfio; Garibaldi, Franco

    2012-01-01

    In this paper we prove that the choice of a suitable treatment of the scintillator surfaces, along with suitable photodetectors electronics and specific algorithms for raw data analysis, allow to achieve an optimal tradeoff between energy, time and DOI resolution, thus strongly supporting the feasibility of a prostate TOF- PET probe, MRI compatible, with the required features and performance. In numbers this means a detector element of 1.5mm x 1.5mm x 10mm, achieving at the same time energy resolution around 11.5%, time-of- flight resolution around 150 ps and DOI resolution even below 1 mm. We stress that such a time resolution allows to increase significantly the Noise Equivalent Counting Rate, and consequently improve the image quality and the lesion detection capability. These individual values correspond to the best obtained so far by other groups, but we got all of them simultaneously. In our opinion this proof of principle paves the way to the feasibility of a TOF-PET MRI compatible probe with unprecede...

  14. Visualization of acetaminophen-induced liver injury by time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Murayama, Yohei; Satoh, Shuya; Hashiguchi, Akinori; Yamazaki, Ken; Hashimoto, Hiroyuki; Sakamoto, Michiie

    2015-11-01

    Time-of-flight secondary ion mass spectrometry (MS) provides secondary ion images that reflect distributions of substances with sub-micrometer spatial resolution. To evaluate the use of time-of-flight secondary ion MS to capture subcellular chemical changes in a tissue specimen, we visualized cellular damage showing a three-zone distribution in mouse liver tissue injured by acetaminophen overdose. First, we selected two types of ion peaks related to the hepatocyte nucleus and cytoplasm using control mouse liver. Acetaminophen-overdosed mouse liver was then classified into three areas using the time-of-flight secondary ion MS image of the two types of peaks, which roughly corresponded to established histopathological features. The ion peaks related to the cytoplasm decreased as the injury became more severe, and their origin was assumed to be mostly glycogen based on comparison with periodic acid-Schiff staining images and reference compound spectra. This indicated that the time-of-flight secondary ion MS image of the acetaminophen-overdosed mouse liver represented the chemical changes mainly corresponding to glycogen depletion on a subcellular scale. In addition, this technique also provided information on lipid species related to the injury. These results suggest that time-of-flight secondary ion MS has potential utility in histopathological applications.

  15. Identification of Bacteria Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Kedney, Mollie G.; Strunk, Kevin B.; Giaquinto, Lisa M.; Wagner, Jennifer A.; Pollack, Sidney; Patton, Walter A.

    2007-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS or simply MALDI) has become ubiquitous in the identification and analysis of biomacromolecules. As a technique that allows for the molecular weight determination of otherwise nonvolatile molecules, MALDI has had a profound impact in the molecular…

  16. Automated data processing of high-resolution mass spectra

    DEFF Research Database (Denmark)

    Hansen, Michael Adsetts Edberg; Smedsgaard, Jørn

    There has been an almost explosive growth in performance and applications of Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry, which today is one of the most efficient tools for screening of metabolites in complex bio-samples. Most efficiently ESI-MS can be used by directly...... infusion of crude extracts into the source taking advantage of the high sensitivity, high mass resolution and accuracy and the limited fragmentation. Unfortunately, there has not been a comparable development in the data processing techniques to fully exploit gain in high resolution and accuracy...... and mass axis on to a fixed one-dimensional array, we obtain a vector that can be used directly as input in multivariate statistics or library search methods. We demonstrate that both cluster- and discriminant analysis as well as PCA (and related methods) can be applied directly on mass spectra from direct...

  17. A collinear tandem time-of-flight mass spectrometer for infrared photodissociation spectroscopy of mass-selected ions

    Institute of Scientific and Technical Information of China (English)

    WANG GuanJun; CHI ChaoXian; XING XiaoPeng; DING ChuanFan; ZHOU MingFei

    2014-01-01

    An apparatus based on collinear tandem time-of-flight mass spectrometer has been designed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase.The ions from a pulsed laser vaporization supersonic ion source are skimmed and mass separated by a Wiley-McLaren time-of-flight mass spectrometer.The ion of interest is mass selected,decelerated and dissociated by a tunable IR laser.The fragment and parent ions are reaccelerated and mass analyzed by the second time-of-flight mass spectrometer.A simple new assembly integrated with mass gate,deceleration and reacceleration ion optics was designed,which allows us to measure the infrared spectra of mass selected ions with high sensitivity and easy timing synchronization.

  18. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    OpenAIRE

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF...

  19. Time-of-flight secondary ion mass spectrometry-based molecular distribution distinguishing healthy and osteoarthritic human cartilage

    CERN Document Server

    Cillero-Pastor, Berta; Kiss, Andras; Blanco, Francisco J; Heeren, Ron M A

    2013-01-01

    Osteoarthritis (OA) is a pathology that ultimately causes joint destruction. The cartilage is one of the principal affected tissues. Alterations in the lipid mediators and an imbalance in the metabolism of cells that form the cartilage (chondrocytes) have been described as contributors to the OA development. In this study, we have studied the distribution of lipids and chemical elements in healthy and OA human cartilage. Time of flight-secondary ion mass spectrometry (TOF-SIMS) allows us to study the spatial distribution of molecules at a high resolution on a tissue section. TOF-SIMS revealed a specific peak profile that distinguishes healthy from OA cartilages. The spatial distribution of cholesterol-related peaks exhibited a remarkable difference between healthy and OA cartilages. A distinctive colocalization of cholesterol and other lipids in the superficial area of the cartilage was found. A higher intensity of oleic acid and other fatty acids in the OA cartilages exhibited a similar localization. On the ...

  20. Construction and simulation of a multi-reflection time-of-flight mass spectrometer at the University of Notre Dame

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, B.E., E-mail: bschult4@nd.edu; Kelly, J.M.; Nicoloff, C.; Long, J.; Ryan, S.; Brodeur, M.

    2016-06-01

    One of the most significant problems in the production of rare isotopes is the simultaneous production of contaminants, often time isobaric. Thus, a high-resolution beam purification method is required which needs to be compatible with both the low yield and short half-life of the desired radionuclide. A multi-reflection time-of-flight mass spectrometer meets all these criteria, in addition to boasting a smaller footprint relative to traditional separator dipole magnets. Such a device is currently under construction at the University of Notre Dame and is intended to be coupled to the IG-ISOL source of the planned cyclotron facility. The motivation and conceptual design are presented, as well as the status of simulations to determine the feasibility of using a Bradbury–Nielsen gate for bunching ion beams during initial system testing.

  1. Construction and simulation of a multi-reflection time-of-flight mass spectrometer at the University of Notre Dame

    Science.gov (United States)

    Schultz, B. E.; Kelly, J. M.; Nicoloff, C.; Long, J.; Ryan, S.; Brodeur, M.

    2016-06-01

    One of the most significant problems in the production of rare isotopes is the simultaneous production of contaminants, often time isobaric. Thus, a high-resolution beam purification method is required which needs to be compatible with both the low yield and short half-life of the desired radionuclide. A multi-reflection time-of-flight mass spectrometer meets all these criteria, in addition to boasting a smaller footprint relative to traditional separator dipole magnets. Such a device is currently under construction at the University of Notre Dame and is intended to be coupled to the IG-ISOL source of the planned cyclotron facility. The motivation and conceptual design are presented, as well as the status of simulations to determine the feasibility of using a Bradbury-Nielsen gate for bunching ion beams during initial system testing.

  2. Isobaric Identification Using Gas-Filled Time-of-Flight Measurements in an Accelerator Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-Jing; RUAN Xiang-Dong; HE Ming; WANG Hui-Juan; LI Guo-Qiang; WU Shao-Yong; DONG Ke-Jun; LIN Min; JIANG Shan

    2005-01-01

    @@ A gas-filled time-of-flight (GF-TOF) detector has been built and developed to improve the ability of isobaric identification in accelerator mass spectrometry (AMS) measurements, and a time resolution (without gas filled)of better than 350ps is achieved. The GF-TOF detector is tested by means of measuring a standard AgCl(36Cl/Cl = 7.6 × 10-9g/g) sample with the 36Cl ion energy of 64, 49 and 33MeV, respectively. 36Cl and 36S particles were successfully separated in the TOF spectra output from the GF-TOF detector. The comparison between the gas-filled time-of-flight method and the △E - E method is described. Some results relative to the GF-TOF method are given as well.

  3. A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

    CERN Document Server

    Ito, Y; Wada, M; Naimi, S; Smorra, C; Sonoda, T; Mita, H; Takamine, A; Okada, K; Ozawa, A; Wollnik, H

    2013-01-01

    A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ~27% for 23Na+ and ~5.1% for 7Li+ has been achieved.

  4. Time-of-Flight Mass Measurements and Their Importance for Nuclear Astrophysics

    Science.gov (United States)

    Matoš, M.; Estrade, A.; Amthor, A. M.; Bazin, D.; Becerril, A.; Elliot, T.; Famiano, M.; Gade, A.; Galaviz, D.; Lorusso, G.; Pereira, J.; Portillo, M.; Rogers, A.; Schatz, H.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.

    2009-03-01

    Atomic masses play an important role in nuclear astrophysics. The lack of experimental values for nuclides of interest has triggered a rapid development of new mass measurement devices around the world, including Time-of-Flight (TOF) mass measurements offering an access to the most exotic nuclides. Recently, the TOF-Brho technique that includes a position measurement for magnetic rigidity correction has been implemented at the NSCL. An experiment with a similar TOF-Brho technique is approved and planned at the next generation radioactive beam facility (RIBF) at RIKEN.

  5. Combined distance-of-flight and time-of-flight mass spectrometer

    Science.gov (United States)

    Enke, Christie G; Ray, Steven J; Graham, Alexander W; Hieftje, Gary M; Barinaga, Charles J; Koppenaal, David W

    2014-02-11

    A combined distance-of-flight mass spectrometry (DOFMS) and time-of-flight mass spectrometry (TOFMS) instrument includes an ion source configured to produce ions having varying mass-to-charge ratios, a first detector configured to determine when each of the ions travels a predetermined distance, a second detector configured to determine how far each of the ions travels in a predetermined time, and a detector extraction region operable to direct portions of the ions either to the first detector or to the second detector.

  6. Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Li, Xiang; Cornish, Timothy; Getty, Stephanie A.; Brinckerhoff, William B.

    2016-01-01

    Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments.

  7. SOI pixel circuits with synchronized TMC for time-of-flight stigmatic imaging mass spectrometry

    CERN Document Server

    Watanabe, Kaori; Fujita, Youichi; Arai, Yasuo; Hazama, Hisanao

    2015-01-01

    We propose SOI pixel circuits with a synchronized time memory cell (TMC) for time-of-flight stigmatic imaging mass spectrometry. The circuits simultaneously detect the position and the fine/coarse flight time of an ion for the MALDI-ToF mass spectrometer. We discuss the circuit design and present the simulation results of a prototype detector comprised of a 32 x 32 pixel array in which each pixel pitch is 40 um and the time resolution is a minimum of 1 ns. The results of transient analysis demonstrate the fully correct synchronous operation at a 100-MHz clock frequency and simultaneous 32-word SRAM writing.

  8. Solid Phase Microextraction and Miniature Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hiller, j.m.

    1999-01-26

    A miniature mass spectrometer, based on the time-of-flight principle, has been developed for the detection of chemical warfare agent precursor molecules. The instrument, with minor modifications, could fulfill many of the needs for sensing organic molecules in various Defense Programs, including Enhanced Surveillance. The basic footprint of the instrument is about that of a lunch box. The instrument has a mass range to about 300, has parts-per-trillion detection limits, and can return spectra in less than a second. The instrument can also detect permanent gases and is especially sensitive to hydrogen. In volume, the device could be manufactured for under $5000.

  9. Fully automatic and precise data analysis developed for time-of-flight mass spectrometry.

    Science.gov (United States)

    Meyer, Stefan; Riedo, Andreas; Neuland, Maike B; Tulej, Marek; Wurz, Peter

    2017-09-01

    Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and, thus, a large amount of data to be analysed. Therefore, faster and especially robust automated data analysis with enhanced accuracy is required. In this contribution, an automatic data analysis software, which allows fast and precise quantitative data analysis of time-of-flight mass spectrometric data, is presented and discussed in detail. A crucial part of this software is a robust and fast peak finding algorithm with a consecutive numerical integration method allowing precise data analysis. We tested our analysis software with data from different time-of-flight mass spectrometers and different measurement campaigns thereof. The quantitative analysis of isotopes, using automatic data analysis, yields results with an accuracy of isotope ratios up to 100 ppm for a signal-to-noise ratio (SNR) of 10(4) . We show that the accuracy of isotope ratios is in fact proportional to SNR(-1) . Furthermore, we observe that the accuracy of isotope ratios is inversely proportional to the mass resolution. Additionally, we show that the accuracy of isotope ratios is depending on the sample width Ts by Ts(0.5) . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  10. One Hundred False-Positive Amphetamine Specimens Characterized by Liquid Chromatography Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Marin, Stephanie J.; Doyle, Kelly; Chang, Annie; Concheiro-Guisan, Marta; Huestis, Marilyn A.; Johnson-Davis, Kamisha L.

    2016-01-01

    Some amphetamine (AMP) and ecstacy (MDMA) urine immunoassay (IA) kits are prone to false-positive results due to poor specificity of the antibody. We employed two techniques, high-resolution mass spectrometry (HRMS) and an in silico structure search, to identify compounds likely to cause false-positive results. Hundred false-positive IA specimens for AMP and/or MDMA were analyzed by an Agilent 6230 time-of-flight (TOF) mass spectrometer. Separately, SciFinder (Chemical Abstracts) was used as an in silico structure search to generate a library of compounds that are known to cross-react with AMP/MDMA IAs. Chemical formulas and exact masses of 145 structures were then compared against masses identified by TOF. Compounds known to have cross-reactivity with the IAs were identified in the structure-based search. The chemical formulas and exact masses of 145 structures (of 20 chemical formulas) were compared against masses identified by TOF. Urine analysis by HRMS correlates accurate mass with chemical formulae, but provides little information regarding compound structure. Structural data of targeted antigens can be utilized to correlate HRMS-derived chemical formulas with structural analogs. PMID:26342055

  11. One Hundred False-Positive Amphetamine Specimens Characterized by Liquid Chromatography Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Marin, Stephanie J; Doyle, Kelly; Chang, Annie; Concheiro-Guisan, Marta; Huestis, Marilyn A; Johnson-Davis, Kamisha L

    2016-01-01

    Some amphetamine (AMP) and ecstacy (MDMA) urine immunoassay (IA) kits are prone to false-positive results due to poor specificity of the antibody. We employed two techniques, high-resolution mass spectrometry (HRMS) and an in silico structure search, to identify compounds likely to cause false-positive results. Hundred false-positive IA specimens for AMP and/or MDMA were analyzed by an Agilent 6230 time-of-flight (TOF) mass spectrometer. Separately, SciFinder (Chemical Abstracts) was used as an in silico structure search to generate a library of compounds that are known to cross-react with AMP/MDMA IAs. Chemical formulas and exact masses of 145 structures were then compared against masses identified by TOF. Compounds known to have cross-reactivity with the IAs were identified in the structure-based search. The chemical formulas and exact masses of 145 structures (of 20 chemical formulas) were compared against masses identified by TOF. Urine analysis by HRMS correlates accurate mass with chemical formulae, but provides little information regarding compound structure. Structural data of targeted antigens can be utilized to correlate HRMS-derived chemical formulas with structural analogs. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Pharmaceutical metabolite profiling using quadrupole/ion mobility spectrometry/time-of-flight mass spectrometry.

    Science.gov (United States)

    Chan, Eric C Y; New, Lee Sun; Yap, Chun Wei; Goh, Lin Tang

    2009-02-01

    The use of hybrid quadrupole ion mobility spectrometry time-of-flight mass spectrometry (Q/IMS/TOFMS) in the metabolite profiling of leflunomide (LEF) and acetaminophen (APAP) is presented. The IMS drift times (T(d)) of the drugs and their metabolites were determined in the IMS/TOFMS experiments and correlated with their exact monoisotopic masses and other in silico generated structural properties, such as connolly molecular area (CMA), connolly solvent-excluded volume (CSEV), principal moments of inertia along the X, Y and Z Cartesian coordinates (MI-X, MI-Y and MI-Z), inverse mobility and collision cross-section (CCS). The correlation of T(d) with these parameters is presented and discussed. IMS/TOF tandem mass spectrometry experiments (MS(2) and MS(3)) were successfully performed on the N-acetyl-p-benzoquinoneimine glutathione (NAPQI-GSH) adduct derived from the in vitro microsomal metabolism of APAP. As comparison, similar experiments were also performed using hybrid triple quadrupole linear ion trap mass spectrometry (QTRAPMS) and quadrupole time-of-flight mass spectrometry (QTOFMS). The abilities to resolve the product ions of the metabolite within the drift tube and fragment the ion mobility resolved product ions in the transfer travelling wave-enabled stacked ring ion guide (TWIG) demonstrated the potential applicability of the Q/IMS/TOFMS technique in pharmaceutical metabolite profiling.

  13. Constant-momentum acceleration time-of-flight mass spectrometry with energy focusing.

    Science.gov (United States)

    Dennis, Elise A; Ray, Steven J; Gundlach-Graham, Alexander W; Enke, Christie G; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2013-12-01

    Fundamental aspects of constant-momentum acceleration time-of-flight mass spectrometry (CMA-TOFMS) are explored as a means to improve mass resolution. By accelerating all ions to the same momentum rather than to the same energy, the effects of the initial ion spatial and energy distributions upon the total ion flight time are decoupled. This decoupling permits the initial spatial distribution of ions in the acceleration region to be optimized independently, and energy focus, including ion turn-around-time error, to be accomplished with a linear-field reflectron. Constant-momentum acceleration also linearly disperses ions across time according to mass-to-charge (m/z) ratio, instead of the quadratic relationship between flight time and m/z found in conventional TOFMS. Here, CMA-TOFMS is shown to achieve simultaneous spatial and energy focusing over a selected portion of the mass spectrum. An orthogonal-acceleration time-of-flight system outfitted with a reduced-pressure DC glow discharge (GD) ionization source is used to demonstrate CMA-TOFMS with atomic ions. The influence of experimental parameters such as the amplitude and width of the time-dependent CMA pulse on mass resolution is investigated, and a useful CMA-TOFMS focusing window of 2 to 18 Da is found for GD-CMA-TOFMS.

  14. TOF plotter—a program to perform routine analysis time-of-flight mass spectral data

    Science.gov (United States)

    Knippel, Brad C.; Padgett, Clifford W.; Marcus, R. Kenneth

    2004-03-01

    The main article discusses the operation and application of the program to mass spectral data files. This laboratory has recently reported the construction and characterization of a linear time-of-flight mass spectrometer (ToF-MS) utilizing a radio frequency glow discharge ionization source. Data acquisition and analysis was performed using a digital oscilloscope and Microsoft Excel, respectively. Presently, no software package is available that is specifically designed for time-of-flight mass spectral analysis that is not instrument dependent. While spreadsheet applications such as Excel offer tremendous utility, they can be cumbersome when repeatedly performing tasks which are too complex or too user intensive for macros to be viable. To address this situation and make data analysis a faster, simpler task, our laboratory has developed a Microsoft Windows-based software program coded in Microsoft Visual Basic. This program enables the user to rapidly perform routine data analysis tasks such as mass calibration, plotting and smoothing on x- y data sets. In addition to a suite of tools for data analysis, a number of calculators are built into the software to simplify routine calculations pertaining to linear ToF-MS. These include mass resolution, ion kinetic energy and single peak identification calculators. A detailed description of the software and its associated functions is presented followed by a characterization of its performance in the analysis of several representative ToF-MS spectra obtained from different GD-ToF-MS systems.

  15. Delayed extraction time-of-flight mass spectrometer with electron impact for PAH studies

    Science.gov (United States)

    Najeeb, P. K.; Kadhane, U.

    2017-03-01

    A time-of-flight (ToF) mass spectrometer with a pulsed electron beam as well as pulsed extraction of the recoil ions, with variable delay is reported. The effectiveness of this technique is highlighted by studying the statistical decay of mono-cations over microsecond time scales. Various details of the design and operation are discussed in the context of electron impact ionization and fragmentation of naphthalene (C10H8). The temporal behavior of acetylene (C2H2) and diacetylene (C4H2) loss is observed and compared with the associated Arrhenius decay constant, internal energy and plasmon excitation energy.

  16. Analysis of ion dynamics and peak shapes for delayed extraction time-of-flight mass spectrometers

    Science.gov (United States)

    Collado, V. M.; Ponciano, C. R.; Fernandez-Lima, F. A.; da Silveira, E. F.

    2004-06-01

    The dependence of time-of-flight (TOF) peak shapes on time-dependent extraction electric fields is studied theoretically. Conditions for time focusing are analyzed both analytically and numerically for double-acceleration-region TOF spectrometers. Expressions for the spectrometer mass resolution and for the critical delay time are deduced. Effects due to a leakage field in the first acceleration region are shown to be relevant under certain conditions. TOF peak shape simulations for the delayed extraction method are performed for emitted ions presenting a Maxwellian initial energy distribution. Calculations are compared to experimental results of Cs+ emission due to CsI laser ablation.

  17. Performance Characteristics of a New Hybrid Triple Quadrupole Time-of-Flight Tandem Mass Spectrometer

    Science.gov (United States)

    Andrews, Genna L.; Simons, Brigitte L.; Young, J. Bryce; Hawkridge, Adam M.; Muddiman, David C.

    2011-01-01

    The TripleTOF 5600 System, a hybrid triple quadrupole time-of-flight mass spectrometer, was evaluated to explore the key figures of merit in generating peptide and protein identifications which included spectral acquisition rates, data quality, proteome coverage, and biological depth. Employing a Saccharomyces cerevisiae tryptic digest, careful consideration of several performance features demonstrated that the speed of the TripleTOF contributed most to the resultant data. The TripleTOF system was operated with 8, 20, and 50 MS/MS events in an effort to compare to other MS technologies and to demonstrate the abilities of the instrument platform. PMID:21619048

  18. A miniature laser ablation time-of-flight mass spectrometer for in situ planetary exploration

    Science.gov (United States)

    Rohner, Urs; Whitby, James A.; Wurz, Peter

    2003-12-01

    We report the development and testing of a miniature mass spectrometer and ion source intended to be deployed on an airless planetary surface to measure the elemental and isotopic composition of rocks and soils. Our design concentrates at this stage on the proposed BepiColombo mission to the planet Mercury. The mass analyser is an axially symmetric reflectron time-of-flight design. The ion source utilizes a laser induced plasma, which is directly coupled into the mass analyser. Laser ablation gives high spatial resolution, and avoids the need for sample preparation. Our prototype instrument has a demonstrated mass resolution m/Dgrm (FWHM) in excess of 600 and a predicted dynamic range of better than four orders of magnitude. Isotopic fractionation effects are found to be minor. We estimate that a flight instrument would have a mass of 500 g (including all electronics), a volume of 650 cm3 and could operate on 3 W power.

  19. ACTRIS ACSM intercomparison - Part I: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with Time-of-Flight ACSM (ToF-ACSM), High Resolution ToF Aerosol Mass Spectrometer (HR-ToF-AMS) and other co-located instruments

    Science.gov (United States)

    Crenn, V.; Sciare, J.; Croteau, P. L.; Verlhac, S.; Fröhlich, R.; Belis, C. A.; Aas, W.; Äijälä, M.; Alastuey, A.; Artiñano, B.; Baisnée, D.; Bonnaire, N.; Bressi, M.; Canagaratna, M.; Canonaco, F.; Carbone, C.; Cavalli, F.; Coz, E.; Cubison, M. J.; Esser-Gietl, J. K.; Green, D. C.; Gros, V.; Heikkinen, L.; Herrmann, H.; Lunder, C.; Minguillón, M. C.; Močnik, G.; O'Dowd, C. D.; Ovadnevaite, J.; Petit, J.-E.; Petralia, E.; Poulain, L.; Priestman, M.; Riffault, V.; Ripoll, A.; Sarda-Estève, R.; Slowik, J. G.; Setyan, A.; Wiedensohler, A.; Baltensperger, U.; Prévôt, A. S. H.; Jayne, J. T.; Favez, O.

    2015-07-01

    As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for three weeks during the late fall-early winter period (November-December 2013). The first week was dedicated to tuning and calibration of each instrument whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium and chloride) in the non-refractory submicron aerosols (NR-PM1) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r2 > 0.9) were observed systematically for each individual ACSM across all chemical families except for chloride for which three ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025) and were found to be of 9, 15, 19, 28 and 36 % for NR-PM1, nitrate, organic matter, sulfate and ammonium respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of ACSMs, detailed intercomparison results are presented as well as a discussion of some recommendations

  20. An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

    Energy Technology Data Exchange (ETDEWEB)

    Shuai, P. [Research Center for Hadron Physics, National Laboratory of Heavy Ion Accelerator Facility in Lanzhou and University of Science and Technology of China, Hefei 230026 (China); Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Xu, X., E-mail: xuxing@impcas.ac.cn [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Y.H., E-mail: yhzhang@impcas.ac.cn [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Xu, H.S. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Litvinov, Yu. A. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt (Germany); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Wang, M. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); and others

    2016-06-01

    Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of the momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in a straight section of a storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

  1. High precision electric gate for time-of-flight ion mass spectrometers

    Science.gov (United States)

    Sittler, Edward C. (Inventor)

    2011-01-01

    A time-of-flight mass spectrometer having a chamber with electrodes to generate an electric field in the chamber and electric gating for allowing ions with a predetermined mass and velocity into the electric field. The design uses a row of very thin parallel aligned wires that are pulsed in sequence so the ion can pass through the gap of two parallel plates, which are biased to prevent passage of the ion. This design by itself can provide a high mass resolution capability and a very precise start pulse for an ion mass spectrometer. Furthermore, the ion will only pass through the chamber if it is within a wire diameter of the first wire when it is pulsed and has the right speed so it is near all other wires when they are pulsed.

  2. An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

    CERN Document Server

    Shuai, P; Zhang, Y H; Xu, H S; Litvinov, Yu A; Wang, M; Tu, X L; Blaum, K; Zhou, X H; Yuan, Y J; Yan, X L; Chen, X C; Chen, R J; Fu, C Y; Ge, Z; Huang, W J; Xing, Y M; Zeng, Q

    2016-01-01

    Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using the cocktail beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in the straight section of storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

  3. Advantages and Applications of Bruker maXis series Ultra High Resolution Time of Flight Mass Spectrometry%Bruker maXis系列超高分辨飞行时间质谱的性能特点和应用

    Institute of Scientific and Technical Information of China (English)

    潘晨松; 张欣怡

    2011-01-01

    2011年3月,Bruker公司在亚特兰大举办的Pittcon展会上推出了新型超高分辨飞行时间质谱产品(UHR-TOF)maXis 4G。这是一次非常大的突破,其分辨率达到了60,000(FWHM),质量准确度小于600 ppb。在2011的美国质谱协会年会上(ASMS),Bruker公司又推出了高性价比的maXis Impact,其分辨率达40,000(FWHM),质量准确度小于1ppm,每秒可以获得50张全谱,动态范围达4个数量级,完全可以满足超高效液相色谱快速分析的要求,实现了真正意义上的发现、鉴定和定量分析于一体,是实验室进行高通量分析的最佳选择。Bruker maXis系列质谱,实现了全范围的高分辨和高灵敏度,满足了用户对质谱同时准确定性和定量的需求,可广泛应用与化合物的表征和定性、痕量多目标物质的快速筛查和定量以及代谢组学、蛋白组学等研究。本文结合典型的应用实例,着重介绍maXis系列质谱的主要性能特点和应用。%In March,Bruker introduced the revolutionary maXis 4G system at Pittcon 2011 in Atlantic.maXis 4G sets entirely new performance heights with record-breaking 60,000 full-sensitivity resolution(FSR) and 600 parts-per-billion(ppb) mass accuracy.At ASMS,June 2011,Bruker announced a robust,affordable instrument maXis impact with uncompromised UHR-QqTOF performance.Delivering 40,000 FSR,1 ppm mass accuracy and more than four orders of magnitude dynamic range while acquiring at up to 50 full spectra per second,the maXis impact is the instrument of choice for high-throughput test laboratories,many of which are already equipped with UHPLC separations to raise throughput.The simultaneous combination of attributes is ideal for many discovery,development,screening and drug metabolism applications which often require both the identification and quantitation of sample components that vary widely in both structure and concentration.maXis impact is a powerful tool for proteomics and

  4. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification of mycobacteria in routine clinical practice

    National Research Council Canada - National Science Library

    El Khéchine, Amel; Couderc, Carine; Flaudrops, Christophe; Raoult, Didier; Drancourt, Michel

    2011-01-01

    .... Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) has previously been proven to effectively identify mycobacteria grown in high-concentration inocula from collections...

  5. An indigenous cluster beam apparatus with a reflectron time-of-flight mass spectrometer

    Indian Academy of Sciences (India)

    G Raina; G U Kulkarni; R T Yadav; V S Ramamurthy; C N R Rao

    2000-04-01

    The design and fabrication of a Smalley-type cluster source in combination with a reflectron based time-of-flight (TOF) mass spectrometer are reported. The generation of clusters is based on supersonic jet expansion of the sampling plume. Sample cells for both liquid and solid targets developed for this purpose are described. Two pulsed Nd-YAG lasers are used in tandem, one (532 nm) for target vapourization and the other (355 nm) for cluster ionization. Methanol clusters of nuclearity up to 14 (mass 500 amu) were produced from liquid methanol as the test sample. The clusters were detected with a mass resolution of ~ 2500 in the R-TOF geometry. Carbon clusters up to a nuclearity of 28 were obtained using a polyimide target. The utility of the instrument is demonstrated by carrying out experiments to generate mixed clusters from alcohol mixtures.

  6. A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y., E-mail: yito@riken.jp [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Schury, P. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States); Wada, M.; Naimi, S. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Smorra, C. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Sonoda, T. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mita, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Takamine, A. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoyama Gakuin University, 4-4-25 Shibuya, Shibuya-ku, Tokyo 150-8366 (Japan); Okada, K. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Ozawa, A. [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Wollnik, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States)

    2013-12-15

    Highlights: • Fast cooling time: 2 ms. • High efficiency: ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +}. • 100% Duty cycle with double trap system. -- Abstract: A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +} has been achieved.

  7. Development of grazing incidence devices for space-borne time of flight mass spectrometry

    Science.gov (United States)

    Cadu, A.; Devoto, P.; Louarn, P.; Sauvaud, J.-A.

    2012-04-01

    Time of flight mass spectrometer is widely used to study space plasmas in planetary and solar missions. This space-borne instrument selects ions in function of their energy through an electrostatic analyzer. Particles are then post-accelerated to energies in the range of 20 keV to cross a carbon foil. At the foil exit, electrons are emitted and separated from ion beam in the time of flight section. A first detector (a Micro-Channel Plate or MCP) emits a start signal at electron arrival and a second one emits a stop signal at incident ion end of path. The time difference gives the speed of the particle and its mass can be calculated, knowing its initial energy. However, current instruments suffer from strong limitations. The post acceleration needs very high voltage power supplies which are heavy, have a high power consumption and imply technical constraints for the development. A typical instrument weighs from 5 to 6 kg, includes a 20 kV power supply, consumes a least 5 W and encounters corona effect and electrical breakdown problems. Moreover, despite the particle high energy range, scattering and straggling phenomena in the carbon foil significantly reduce the instrument overall resolution. Some methods, such as electrostatic focus lenses or reflectrons, really improve mass separation but global system efficiency remains very low because of the charge state dependence of such devices. The main purpose of our work is to replace carbon foil by grazing incidence MCP's - also known as MPO's, for Micro Pore Optics - for electron emission. Thus, incident particles would back-scatter onto the channel inner surface with an angle of a few degrees. With this solution, we can decrease dispersion sources and lower the power supplies to post accelerate ions. The result would be a lighter and simpler instrument with a substantial resolution improvement. We have first simulated MPO's behavior with TRIM and MARLOWE Monte-Carlo codes. Energy scattering and output angle computed

  8. Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions

    Science.gov (United States)

    Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.; Tawalbeh, R.; Glenar, D.; Elsila, J. E.; Callahan, M.

    2012-01-01

    Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) is a versatile, low-complexity instrument class that holds significant promise for future landed in situ planetary missions that emphasize compositional analysis of surface materials. Here we describe a 5kg-class instrument that is capable of detecting and analyzing a variety of analytes directly from rock or ice samples. Through laboratory studies of a suite of representative samples, we show that detection and analysis of key mineral composition, small organics, and particularly, higher molecular weight organics are well suited to this instrument design. A mass range exceeding 100,000 Da has recently been demonstrated. We describe recent efforts in instrument prototype development and future directions that will enhance our analytical capabilities targeting organic mixtures on primitive and icy bodies. We present results on a series of standards, simulated mixtures, and meteoritic samples.

  9. SPIRAL2/DESIR high resolution mass separator

    Energy Technology Data Exchange (ETDEWEB)

    Kurtukian-Nieto, T., E-mail: kurtukia@cenbg.in2p3.fr [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Baartman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver B.C., V6T 2A3 (Canada); Blank, B.; Chiron, T. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Davids, C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Delalee, F. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Duval, M. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); El Abbeir, S.; Fournier, A. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Lunney, D. [CSNSM-IN2P3-CNRS, Université de Paris Sud, F-91405 Orsay (France); Méot, F. [BNL, Upton, Long Island, New York (United States); Serani, L. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Stodel, M.-H.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); and others

    2013-12-15

    DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. DESIR includes a high-resolution mass separator (HRS) with a designed resolving power m/Δm of 31,000 for a 1 π-mm-mrad beam emittance, obtained using a high-intensity beam cooling device. The proposed design consists of two 90-degree magnetic dipoles, complemented by electrostatic quadrupoles, sextupoles, and a multipole, arranged in a symmetric configuration to minimize aberrations. A detailed description of the design and results of extensive simulations are given.

  10. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    Energy Technology Data Exchange (ETDEWEB)

    Estrade, Alfredo [National Superconducting Cyclotron Laboratory (NSCL); Matos, M. [Louisiana State University; Schatz, Hendrik [Michigan State University, East Lansing; Amthor, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Bazin, D. [National Superconducting Cyclotron Laboratory (NSCL); Beard, Mary [University of Notre Dame, IN; Becerril, A. [National Superconducting Cyclotron Laboratory (NSCL); Brown, Edward [Michigan State University, East Lansing; Elliot, T [National Superconducting Cyclotron Laboratory (NSCL); Gade, A. [National Superconducting Cyclotron Laboratory (NSCL); Galaviz, D. [National Superconducting Cyclotron Laboratory (NSCL); George, S. [National Superconducting Cyclotron Laboratory (NSCL); Gupta, Sanjib [Indian Institute of Technology, Kanpur; Hix, William Raphael [ORNL; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL); Moeller, Peter [Los Alamos National Laboratory (LANL); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Portillo, M. [National Superconducting Cyclotron Laboratory (NSCL); Rogers, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Shapira, Dan [ORNL; Smith, E. [Ohio State University; Stolz, A. [Michigan State University, East Lansing; Wallace, M. [Los Alamos National Laboratory (LANL); Wiescher, Michael [University of Notre Dame, IN

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Supercon- ducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the Sc Ni element range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of 61V, 63Cr, 66Mn, and 74Ni were measured for the first time with mass excesses of 30.510(890) MeV, 35.280(650) MeV, 36.900(790) MeV, and 49.210(990) MeV, respectively. With the measurement of the 66Mn mass, the location of the two dominant heat sources in the outer crust of accreting neutron stars, which exhibit so called superbursts, is now experimentally constrained. We find that the location of the 66Fe 66Mn electron capture transition occurs sig- nificantly closer to the surface than previously assumed because our new experimental Q-value is 2.1 MeV smaller than predicted by the FRDM mass model. The results also provide new insights into the structure of neutron-rich nuclei around N = 40.

  11. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Directory of Open Access Journals (Sweden)

    T. Dickel

    2015-05-01

    Full Text Available 211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC. They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS. The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  12. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Dickel, T. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Plaß, W.R., E-mail: Wolfgang.R.Plass@exp2.physik.uni-giessen.de [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Ayet San Andres, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Ebert, J. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Geissel, H.; Haettner, E. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Hornung, C. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Miskun, I. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Pietri, S.; Purushothaman, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); and others

    2015-05-11

    {sup 211}Po ions in the ground and isomeric states were produced via {sup 238}U projectile fragmentation at 1000 MeV/u. The {sup 211}Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  13. Beer fingerprinting by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Šedo, Ondrej; Márová, Ivana; Zdráhal, Zbyněk

    2012-11-15

    A method allowing parallel fingerprinting of proteins and maltooligosaccharides directly from untreated beer samples is presented. These two classes of compounds were detected by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight-Mass Spectrometry (MALDI-TOF-MS) analysis of beer mixed with 2,5-dihydroxybenzoic acid solution. The maltooligosaccharide profiles acquired from the MALDI sample spot center were not found characteristic for beers of different source and technology. On the other hand, according to profiles containing protein signals acquired from crystals formed on the border of the MALDI sample spot, we were able to distinguish beer samples of the same brand produced by different breweries. The discriminatory abilities of the method were further examined on a set of 17 lager beers, where the fingerprints containing protein signals enabled resolution of majority of examined brands. We propose MALDI-TOF-MS profiling as a rapid tool for beer brewing technology process monitoring, quality control, and determination of beer authenticity.

  14. Probing nanoparticles and nanoparticle-conjugated biomolecules using time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Kim, Young-Pil; Shon, Hyun Kyong; Shin, Seung Koo; Lee, Tae Geol

    2015-01-01

    Bio-conjugated nanoparticles have emerged as novel molecular probes in nano-biotechnology and nanomedicine and chemical analyses of their surfaces have become challenges. The time-of-flight (TOF) secondary ion mass spectrometry (SIMS) has been one of the most powerful surface characterization techniques for both nanoparticles and biomolecules. When combined with various nanoparticle-based signal enhancing strategies, TOF-SIMS can probe the functionalization of nanoparticles as well as their locations and interactions in biological systems. Especially, nanoparticle-based SIMS is an attractive approach for label-free drug screening because signal-enhancing nanoparticles can be designed to directly measure the enzyme activity. The chemical-specific imaging analysis using SIMS is also well suited to screen nanoparticles and nanoparticle-biomolecule conjugates in complex environments. This review presents some recent applications of nanoparticle-based TOF-SIMS to the chemical analysis of complex biological systems.

  15. Campaign 1.7 Pu Aging. Development of Time of Flight Secondary Ion Mass Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Venhaus, Thomas J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-09

    The first application of Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) to an aged plutonium surface has resulted in a rich set of surface chemistry data, as well as some unexpected results. FY15 was highlighted by not only the first mapping of hydrogen-containing features within the metal, but also a prove-in series of experiments using the system’s Sieverts Reaction Cell. These experiments involved successfully heating the sample to ~450 oC for nearly 24 hours while the sample was dosed several times with hydrogen, followed by an in situ ToF-SIMS analysis. During this year, the data allowed for better and more consistent identification of the myriad peaks that result from the SIMS sputter process. In collaboration with the AWE (U.K), the system was also fully aligned for sputter depth profiling for future experiments.

  16. TOFwave: reproducibility in biomarker discovery from time-of-flight mass spectrometry data.

    Science.gov (United States)

    Chierici, Marco; Albanese, Davide; Franceschi, Pietro; Furlanello, Cesare

    2012-11-01

    Many are the sources of variability that can affect reproducibility of disease biomarkers from time-of-flight (TOF) Mass Spectrometry (MS) data. Here we present TOFwave, a complete software pipeline for TOF-MS biomarker identification, that limits the impact of parameter tuning along the whole chain of preprocessing and model selection modules. Peak profiles are obtained by a preprocessing based on Continuous Wavelet Transform (CWT), coupled with a machine learning protocol aimed at avoiding selection bias effects. Only two parameters (minimum peak width and a signal to noise cutoff) have to be explicitly set. The TOFwave pipeline is built on top of the mlpy Python package. Examples on Matrix-Assisted Laser Desorption and Ionization (MALDI) TOF datasets are presented. Software prototype, datasets and details to replicate results in this paper can be found at http://mlpy.sf.net/tofwave/.

  17. Time-of-flight mass spectrographs—From ions to neutral atoms

    Science.gov (United States)

    Möbius, E.; Galvin, A. B.; Kistler, L. M.; Kucharek, H.; Popecki, M. A.

    2016-12-01

    After their introduction to space physics in the mid 1980s time-of-flight (TOF) spectrographs have become a main staple in spaceborne mass spectrometry. They have largely replaced magnetic spectrometers, except when extremely high mass resolution is required to identify complex molecules, for example, in the vicinity of comets or in planetary atmospheres. In combination with electrostatic analyzers and often solid state detectors, TOF spectrographs have become key instruments to diagnose space plasma velocity distributions, mass, and ionic charge composition. With a variety of implementation schemes that also include isochronous electric field configurations, TOF spectrographs can respond to diverse science requirements. This includes a wide range in mass resolution to allow the separation of medium heavy isotopes or to simply provide distributions of the major species, such as H, He, and O, to obtain information on source tracers or mass fluxes. With a top-hat analyzer at the front end, or in combination with deflectors for three-axis stabilized spacecraft, the distribution function of ions can be obtained with good time resolution. Most recently, the reach of TOF ion mass spectrographs has been extended to include energetic neutral atoms. After selecting the arrival direction with mechanical collimation, followed by conversion to ions, adapted TOF sensors form a new branch of the spectrograph family tree. We review the requirements, challenges, and implementation schemes for ion and neutral atom spectrographs, including potential directions for the future, while largely avoiding overlap with complementary contributions in this special issue.

  18. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    CERN Document Server

    Estrade, A; Schatz, H; Amthor, A M; Bazin, D; Beard, M; Becerril, A; Brown, E F; Cyburt, R; Elliot, T; Gade, A; Galaviz, D; George, S; Gupta, S S; Hix, W R; Lau, R; Lorusso, G; Moller, P; Pereira, J; Portillo, M; Rogers, A M; Shapira, D; Smith, E; Stolz, A; Wallace, M; Wiescher, M

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Superconducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the scandium -- nickel range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of $^{61}${V}, $^{63}${Cr}, $^{66}${Mn}, and $^{74}${Ni} were measured for the first time with mass excesses of $-30.510(890)$ MeV, $-35.280(650)$ MeV, $-36.900(790)$ MeV, and $-49.210(990)$ MeV, respectively. With the measurement of the $^{66}$Mn mass, the locations of the two dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit superbursts are now experimentally constrained. We find that the location of the $^{66}$Fe$\\rightarrow^{66}$Mn electron capture transition occurs signi...

  19. Optimizing sequence coverage for a moderate mass protein in nano-electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Matsuda, Ryan; Kolli, Venkata; Woods, Megan; Dodds, Eric D; Hage, David S

    2016-09-15

    Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C, and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA.

  20. Use of electron ionization and atmospheric pressure chemical ionization in gas chromatography coupled to time-of-flight mass spetrometry for screening and identification of organic pollutants in waters

    NARCIS (Netherlands)

    Portoles, T.; Mol, J.G.J.; Sancho, J.V.; Hernandez, F.

    2014-01-01

    A new approach has been developed for multiclass screening of organic contaminants in water based on the use of gas chromatography coupled to hybrid quadrupole high-resolution time-of-flight mass spectrometry with atmospheric pressure chemical ionization (GC–(APCI)QTOF MS). The soft ionization promo

  1. Highly miniaturized laser ablation time-of-flight mass spectrometer for a planetary rover

    Science.gov (United States)

    Rohner, Urs; Whitby, James A.; Wurz, Peter; Barabash, Stas

    2004-05-01

    We report the development and testing of a highly miniaturized mass spectrometer and ion source intended to be deployed on an airless planetary surface to measure the elemental and isotopic composition of solids, e.g., rocks and soils. Our design concentrates at this stage on the proposed BepiColombo mission to the planet Mercury. The mass analyzer is a novel combination of an electrostatic analyzer and a reflectron time-of-flight design. The ion source utilizes a laser induced plasma, which is directly coupled into the mass analyzer. Laser ablation gives high spatial resolution and avoids the need for sample preparation. Our prototype instrument has a demonstrated mass resolution m/Δm full width at half maximum in excess of 180 and a predicted dynamic range of better than five orders of magnitude. We estimate that a flight instrument would have a mass of 280 g (including laser and all electronics), a volume of 84 cm3, and could operate on 3 W power.

  2. Single-reference high-precision mass measurement with a multi-reflection time-of-flight mass spectrograph

    CERN Document Server

    Ito, Y; Wada, M; Naimi, S; Sonoda, T; Mita, H; Arai, F; Takamine, A; Okada, K; Ozawa, A; Wollnik, H

    2013-01-01

    A multi-reflection time-of-flight mass spectrograph, competitive with Penning trap mass spectrometers, has been built at RIKEN. We have performed a first online mass measurement, using 8Li+ (T1/2 = 838 ms). A new analysis method has been realized, with which, using only 12C+ references, the mass excess of 8Li was accurately determined to be 20947.6(15)(34) keV (dm/m = 6.6 x 10-7). The speed, precision and accuracy of this first online measurement exemplifies the potential for using this new type of mass spectrograph for precision measurements of short-lived nuclei.

  3. Repetitively sampled time-of-flight mass spectrometry for gas-phase kinetics studies

    Science.gov (United States)

    Fockenberg, Christopher; Bernstein, Herbert J.; Hall, Gregory E.; Muckerman, James T.; Preses, Jack M.; Sears, Trevor J.; Weston, Ralph E.

    1999-08-01

    An apparatus has been constructed to study radical-radical reactions in the gas phase. It consists of a tubular quartz reactor in which radicals are produced by flash photolysis using an excimer laser as light source. The composition of the gas mixture is analyzed in situ by photoionizing sampled gases using the vacuum ultraviolet emission of a hollow cathode lamp and subsequent time-of-flight mass spectrometry. A simple arrangement of grids at the entrance to the flight tube is used to interrupt the constant flux of ions by application of a combination of constant and pulsed voltages. Individual mass spectra can be taken at a repetition rate of around 20 kHz following each photolysis event. Signal counts from a specified number of consecutive mass spectra are fed into a 2 GHz multiscaler and accumulated as a sampling-time-indexed series of mass spectra. This allows simultaneous observation of the concentrations of multiple transient or stable species on a millisecond time scale. To achieve a suitable signal-to-noise ratio, signals were typically accumulated over several tens of thousands of laser shots at a pulse rate of 10-15 Hz.

  4. Time-of-Flight Mass Measurements for Nuclear Processes in Neutron Star Crusts

    Science.gov (United States)

    Estradé, A.; Matoš, M.; Schatz, H.; Amthor, A. M.; Bazin, D.; Beard, M.; Becerril, A.; Brown, E. F.; Cyburt, R.; Elliot, T.; Gade, A.; Galaviz, D.; George, S.; Gupta, S. S.; Hix, W. R.; Lau, R.; Lorusso, G.; Möller, P.; Pereira, J.; Portillo, M.; Rogers, A. M.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, M.

    2011-10-01

    We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of V61, Cr63, Mn66, and Ni74 measured for the first time with mass excesses of -30.510(890)MeV, -35.280(650)MeV, -36.900(790)MeV, and -49.210(990)MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the Fe66→Mn66 electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface.

  5. Multiclass semi-volatile compounds determination in wine by gas chromatography accurate time-of-flight mass spectrometry.

    Science.gov (United States)

    Rodríguez-Cabo, T; Rodríguez, I; Ramil, M; Silva, A; Cela, R

    2016-04-15

    The performance of gas chromatography (GC) with accurate, high resolution mass spectrometry (HRMS) for the determination of a group of 39 semi-volatile compounds related to wine quality (pesticide residues, phenolic off-flavours, phenolic pollutants and bioactive stilbenes) is investigated. Solid-phase extraction (SPE) was used as extraction technique, previously to acetylation (phenolic compounds) and dispersive liquid-liquid microextraction (DLLME) concentration. Compounds were determined by GC coupled to a quadrupole time-of-flight (QTOF) MS system through an electron ionization (EI) source. The final method attained limits of quantification (LOQs) at the very low ng mL(-1) level, covering the range of expected concentrations for target compounds in red and white wines. For 38 out of 39 compounds, performance of sample preparation and determination steps were hardly affected by the wine matrix; thus, accurate recoveries were achieved by using pseudo-external calibration. Levels of target compounds in a set of 25 wine samples are reported. The capabilities of the described approach for the post-run identification of species not considered during method development, without retention time information, are illustrated and discussed with selected examples of compounds from different classes.

  6. Development of a Portable Single Photon Ionization-Photoelectron Ionization Time-of-Flight Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    Yunguang Huang

    2015-01-01

    Full Text Available A vacuum ultraviolet lamp based single photon ionization- (SPI- photoelectron ionization (PEI portable reflecting time-of-flight mass spectrometer (TOFMS was designed for online monitoring gas samples. It has a dual mode ionization source: SPI for analyte with ionization energy (IE below 10.6 eV and PEI for IE higher than 10.6 eV. Two kinds of sampling inlets, a capillary inlet and a membrane inlet, are utilized for high concentration and trace volatile organic compounds, respectively. A mass resolution of 1100 at m/z 64 has been obtained with a total size of 40 × 31 × 29 cm, the weight is 27 kg, and the power consumption is only 70 W. A mixture of benzene, toluene, and xylene (BTX, SO2, and discharging products of SF6 were used to test its performance, and the result showed that the limit of quantitation for BTX is as low as 5 ppbv (S/N = 10 : 1 with linear dynamic ranges greater than four orders of magnitude. The portable TOFMS was also evaluated by analyzing volatile organic compounds from wine and decomposition products of SF6 inside of a gas-insulated switchgear.

  7. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    Science.gov (United States)

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers. PMID:21382968

  8. Laser desorption time-of-flight mass spectrometry of vacuum UV photo-processed methanol ice

    Science.gov (United States)

    Paardekooper, D. M.; Bossa, J.-B.; Linnartz, H.

    2016-07-01

    Context. Methanol in the interstellar medium mainly forms upon sequential hydrogenation of solid CO. With typical abundances of up to 15% (with respect to water) it is an important constituent of interstellar ices where it is considered as a precursor in the formation of large and complex organic molecules (COMs), e.g. upon vacuum UV (VUV) photo-processing or exposure to cosmic rays. Aims: This study aims at detecting novel complex organic molecules formed during the VUV photo-processing of methanol ice in the laboratory using a technique more sensitive than regular surface diagnostic tools. In addition, the formation kinetics of the main photo-products of methanol are unravelled for an astronomically relevant temperature (20 K) and radiation dose. Methods: The VUV photo-processing of CH3OH ice is studied by applying laser desorption post-ionisation time-of-flight mass spectrometry (LDPI TOF-MS), and analysed by combining molecule-specific fragmentation and desorption features. Results: The mass spectra correspond to fragment ions originating from a number of previously recorded molecules and from new COMs, such as the series (CO)xH, with x = 3 and y prebiotic glycerin belongs. The formation of these large COMs has not been reported in earlier photolysis studies and suggests that such complex species may form in the solid state under interstellar conditions.

  9. Development of a portable time-of-flight membrane inlet mass spectrometer for environmental analysis

    Science.gov (United States)

    White, A. J.; Blamire, M. G.; Corlett, C. A.; Griffiths, B. W.; Martin, D. M.; Spencer, S. B.; Mullock, S. J.

    1998-02-01

    The benefits of on-site analysis of environmental pollutants are well known, with such techniques increasing sample throughput and reducing the overall cost of pollution level monitoring. This article describes a transportable time-of-flight (TOF) mass spectrometer, based upon a converging, annular TOF (CAT) arrangement. The instrument, the transportable CAT or T-CAT is battery powered and self-contained. The vacuum chamber is never vented and is kept at a very low pressure, even during analysis. Sample gases are admitted to the mass spectrometer via a membrane inlet system. Data collection and analysis are accomplished via a portable PC. The T-CAT is capable of detection limits approaching those of more conventional, nonportable design. The device shows reasonable linearity over wide concentration ranges. Initial results indicate that the T-CAT will be capable of use in a wide range of applications, particularly for environmental monitoring. This article describes the features of the T-CAT, and presents initial results from the membrane inlet/T-CAT system.

  10. Implementation of Ion/Ion Reactions in a Quadrupole/Time-of-Flight Tandem Mass Spectrometer

    Science.gov (United States)

    Xia, Yu; Chrisman, Paul A.; Erickson, David E.; Liu, Jian; Liang, Xiaorong; Londry, Frank A.; Yang, Min J.; McLuckey, Scott A.

    2008-01-01

    A commercial quadrupole/time-of-flight (QqTOF) tandem mass spectrometer has been adapted for ion/ion reaction studies. To enable mutual storage of oppositely charged ions in a linear ion trap, the oscillating quadrupole field of the second quadrupole of the system (Q2) serves to store ions in the radial dimension while auxiliary RF is superposed on the end lenses of Q2 during the reaction period to create barriers in the axial dimension. A pulsed dual electrospray (ESI) source is directly coupled to the instrument interface for the purpose of proton transfer reactions. Singly and doubly charged protein ions as high in mass as 66 kDa are readily formed and observed after proton transfer reactions. For the modified instrument, the mass resolving power is about 8000 for a wide m/z range and the mass accuracy is ~20 ppm for external calibration and ~5 ppm for internal calibration after ion/ion reactions. Parallel ion parking is demonstrated with a six-component protein mixture, which shows the potential application of reducing spectral complexity and concentrating certain charge states. The current system has high flexibility with respect to defining MSn experiments involving collision-induced dissociation (CID) and ion/ion reactions. Protein precursor and CID product masses can be determined with good accuracy, providing an attractive platform for top-down proteomics. Electron transfer dissociation (ETD) ion/ion reactions are implemented by using a pulsed nano-ESI/atmospheric pressure chemical ionization (APCI) dual source for ionization. The reaction between protonated peptide ions and radical anions of 1,3-dinitrobenzene formed exclusively c- and z- type fragment ions. PMID:16771545

  11. Application of matrix-assisted laser desorption/ionization to on-line aerosol time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Stowers, M.A.; Wuijckhuijse, A.L. van; Marijnissen, J.C.M.; Scarlett, B.; Baar, B.L.M. van; Kientz, Ch.E.

    2000-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of- flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated wi

  12. Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

    CSIR Research Space (South Africa)

    Raseleka, RM

    2004-01-01

    Full Text Available sulfate, chlo- rides of sodium, potassium, caesium, magnesium, calcium and strontium were vaporized in the graphite furnace. The vapors Fig. 1 UV absorption spectra of MgSO4,H2SO4 and sulfur powder. :10.1039/b400792a J. Anal. At. Spectrom., 2004, 19, 899... acquisition stages are 5 and 6. Fig. 2 (a) Electrothermal vaporizer coupled to a time of flight mass spectrometer. (b). Reflectron type time of flight mass spectrometer. 900 J. Anal. At. Spectrom., 2004, 19, 899?905 of the laser (10 Hz), the signals shown...

  13. Determination of triacetone triperoxide using ultraviolet femtosecond multiphoton ionization time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ezoe, Ryota [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Imasaka, Tomoko [Laboratory of Chemistry, Graduate School of Design, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka 815-8540 (Japan); Imasaka, Totaro, E-mail: imasaka@cstf.kyushu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Division of Optoelectronics and Photonics, Center for Future Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-01-01

    Highlights: • A UV ultrashort laser pulse was useful for ionization of triacetone triperoxide. • A molecular ion was strongly enhanced in multiphoton ionization mass spectrometry. • Triacetone triperoxide in the human blood was measured without any interferences. • An organic compound of phorone was formed in the human blood from acetone. - Abstract: Triacetone triperoxide (TATP), an explosive compound, was measured using gas chromatography combined with multiphoton ionization time-of-flight mass spectrometry (GC/MPI-TOFMS). By decreasing the pulse width of a femtosecond laser from 80 to 35 fs, a molecular ion was drastically enhanced and was measured as one of the major ions in the mass spectrum. The detection limits obtained using the molecular (M·{sup +}) and fragment (C{sub 2}H{sub 3}O{sup +}) ions were similar or slightly superior to those obtained using conventional mass spectrometry based on electron and chemical ionization. In order to improve the reliability, an isotope of TATP, i.e., TATP-d18, was synthesized and used as an internal standard in the trace analysis of TATP in a sample of human blood. TATP could be identified in a two-dimensional display, even though numerous interfering compounds were present in the sample. Acetone, which is frequently used as a solvent in sampling TATP, produced a chemical species with a retention time nearly identical to that of TATP and provided a C{sub 2}H{sub 3}O{sup +} fragment ion that was employed for measuring a chromatogram of TATP in conventional MS. This compound, the structure of which was assigned as phorone, was clearly differentiated from TATP based on a molecular ion observable in MPI-TOFMS.

  14. Development of analytically capable time-of-flight mass spectrometer with continuous ion introduction

    Science.gov (United States)

    Hárs, György; Dobos, Gábor

    2010-03-01

    The present article describes the results and findings explored in the course of the development of the analytically capable prototype of continuous time-of-flight (CTOF) mass spectrometer. Currently marketed pulsed TOF (PTOF) instruments use ion introduction with a 10 ns or so pulse width, followed by a waiting period roughly 100 μs. Accordingly, the sample is under excitation in 10-4 part of the total measuring time. This very low duty cycle severely limits the sensitivity of the PTOF method. A possible approach to deal with this problem is to use linear sinusoidal dual modulation technique (CTOF) as described in this article. This way the sensitivity of the method is increased, due to the 50% duty cycle of the excitation. All other types of TOF spectrometer use secondary electron multiplier (SEM) for detection, which unfortunately discriminates in amplification in favor of the lighter ions. This discrimination effect is especially undesirable in a mass spectrometric method, which targets high mass range. In CTOF method, SEM is replaced with Faraday cup detector, thus eliminating the mass discrimination effect. Omitting SEM is made possible by the high ion intensity and the very slow ion detection with some hundred hertz detection bandwidth. The electrometer electronics of the Faraday cup detector operates with amplification 1010 V/A. The primary ion beam is highly monoenergetic due to the construction of the ion gun, which made possible to omit any electrostatic mirror configuration for bunching the ions. The measurement is controlled by a personal computer and the intelligent signal generator Type Tabor WW 2571, which uses the direct digital synthesis technique for making arbitrary wave forms. The data are collected by a Labjack interface board, and the fast Fourier transformation is performed by the software. Noble gas mixture has been used to test the analytical capabilities of the prototype setup. Measurement presented proves the results of the mathematical

  15. Development of analytically capable time-of-flight mass spectrometer with continuous ion introduction.

    Science.gov (United States)

    Hárs, György; Dobos, Gábor

    2010-03-01

    The present article describes the results and findings explored in the course of the development of the analytically capable prototype of continuous time-of-flight (CTOF) mass spectrometer. Currently marketed pulsed TOF (PTOF) instruments use ion introduction with a 10 ns or so pulse width, followed by a waiting period roughly 100 micros. Accordingly, the sample is under excitation in 10(-4) part of the total measuring time. This very low duty cycle severely limits the sensitivity of the PTOF method. A possible approach to deal with this problem is to use linear sinusoidal dual modulation technique (CTOF) as described in this article. This way the sensitivity of the method is increased, due to the 50% duty cycle of the excitation. All other types of TOF spectrometer use secondary electron multiplier (SEM) for detection, which unfortunately discriminates in amplification in favor of the lighter ions. This discrimination effect is especially undesirable in a mass spectrometric method, which targets high mass range. In CTOF method, SEM is replaced with Faraday cup detector, thus eliminating the mass discrimination effect. Omitting SEM is made possible by the high ion intensity and the very slow ion detection with some hundred hertz detection bandwidth. The electrometer electronics of the Faraday cup detector operates with amplification 10(10) V/A. The primary ion beam is highly monoenergetic due to the construction of the ion gun, which made possible to omit any electrostatic mirror configuration for bunching the ions. The measurement is controlled by a personal computer and the intelligent signal generator Type Tabor WW 2571, which uses the direct digital synthesis technique for making arbitrary wave forms. The data are collected by a Labjack interface board, and the fast Fourier transformation is performed by the software. Noble gas mixture has been used to test the analytical capabilities of the prototype setup. Measurement presented proves the results of the

  16. Shock tube/time-of-flight mass spectrometer for high temperature kinetic studies.

    Science.gov (United States)

    Tranter, Robert S; Giri, Binod R; Kiefer, John H

    2007-03-01

    A shock tube (ST) with online, time-of-flight mass spectrometric (TOF-MS) detection has been constructed for the study of elementary reactions at high temperature. The ST and TOF-MS are coupled by a differentially pumped molecular beam sampling interface, which ensures that the samples entering the TOF-MS are not contaminated by gases drawn from the cold end wall thermal boundary layer in the ST. Additionally, the interface allows a large range of postshock pressures to be used in the shock tube while maintaining high vacuum in the TOF-MS. The apparatus and the details of the sampling system are described along with an analysis in which cooling of the sampled gases and minimization of thermal boundary layer effects are discussed. The accuracy of kinetic measurements made with the apparatus has been tested by investigating the thermal unimolecular dissociation of cyclohexene to ethylene and 1,3-butadiene, a well characterized reaction for which considerable literature data that are in good agreement exist. The experiments were performed at nominal reflected shock wave pressures of 600 and 1300 Torr, and temperatures ranging from 1260 to 1430 K. The rate coefficients obtained are compared with the earlier shock tube studies and are found to be in very good agreement. As expected no significant difference is observed in the rate constant between pressures of 600 and 1300 Torr.

  17. Liquid chromatography quadrupole time-of-flight mass spectrometry selective determination of ochratoxin A in wine.

    Science.gov (United States)

    Rodríguez-Cabo, T; Rodríguez, I; Ramil, M; Cela, R

    2016-05-15

    The performance of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for ochratoxin A (OTA) determination in wine is evaluated for the first time. Sample preparation was optimized to obtain quantitative recoveries at the same time that the efficiency of electrospray ionization (ESI) remained unaltered between sample extracts and calibration standards. Under final conditions, samples (20 mL) were concentrated using a reversed-phase solid-phase extraction (SPE) cartridge, followed by OTA elution with 1 mL of ethyl acetate. The absolute recoveries of the method, established against calibration standards, were 91-121% and 90-113% (without and with internal standard correction, respectively), for wines fortified at 3 concentration levels. The attained LOQ (0.05 ng mL(-1)) remained below the maximum permitted OTA concentration (2 ng mL(-1)) in dry wines. The method was applied to different samples, with OTA being found in some dessert wines at concentrations below 1 ng mL(-1). The ethyl ester of OTA (OTC) could be identified in the same wine samples from its accurate full product ion spectra.

  18. Advances in quantitative hepcidin measurements by time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Dorine W Swinkels

    Full Text Available Assays for the detection of the iron regulatory hormone hepcidin in plasma or urine have not yet been widely available, whereas quantitative comparisons between hepcidin levels in these different matrices were thus far even impossible due to technical restrictions. To circumvent these limitations, we here describe several advances in time-of flight mass spectrometry (TOF MS, the most important of which concerned spiking of a synthetic hepcidin analogue as internal standard into serum and urine samples. This serves both as a control for experimental variation, such as recovery and matrix-dependent ionization and ion suppression, and at the same time allows value assignment to the measured hepcidin peak intensities. The assay improvements were clinically evaluated using samples from various patients groups and its relevance was further underscored by the significant correlation of serum hepcidin levels with serum iron indices in healthy individuals. Most importantly, this approach allowed kinetic studies as illustrated by the paired analyses of serum and urine samples, showing that more than 97% of the freely filtered serum hepcidin can be reabsorbed in the kidney. Thus, the here reported advances in TOF MS-based hepcidin measurements represent critical steps in the accurate quantification of hepcidin in various body fluids and pave the way for clinical studies on the kinetic behavior of hepcidin in both healthy and diseased states.

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

    Directory of Open Access Journals (Sweden)

    Fei Gao

    2016-08-01

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

  20. Gas-phase pesticide measurement using iodide ionization time-of-flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. Murschell

    2017-06-01

    Full Text Available Volatilization and subsequent processing in the atmosphere are an important environmental pathway for the transport and chemical fate of pesticides. However, these processes remain a particularly poorly understood component of pesticide lifecycles due to analytical challenges in measuring pesticides in the atmosphere. Most pesticide measurements require long (hours to days sampling times coupled with offline analysis, inhibiting observation of meteorologically driven events or investigation of rapid oxidation chemistry. Here, we present chemical ionization time-of-flight mass spectrometry with iodide reagent ions as a fast and sensitive measurement of four current-use pesticides. These semi-volatile pesticides were calibrated with injections of solutions onto a filter and subsequently volatilized to generate gas-phase analytes. Trifluralin and atrazine are detected as iodide–molecule adducts, while permethrin and metolachlor are detected as adducts between iodide and fragments of the parent analyte molecule. Limits of detection (1 s are 0.37, 0.67, 0.56, and 1.1 µg m−3 for gas-phase trifluralin, metolachlor, atrazine, and permethrin, respectively. The sensitivities of trifluralin and metolachlor depend on relative humidity, changing as much as 70 and 59, respectively, as relative humidity of the sample air varies from 0 to 80 %. This measurement approach is thus appropriate for laboratory experiments and potentially near-source field measurements.

  1. Analytical strategy based on the combination of gas chromatography coupled to time-of-flight and hybrid quadrupole time-of-flight mass analyzers for non-target analysis in food packaging.

    Science.gov (United States)

    Cherta, L; Portolés, T; Pitarch, E; Beltran, J; López, F J; Calatayud, C; Company, B; Hernández, F

    2015-12-01

    The potential of an advanced analytical strategy based on the use of gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS) with two different analyzers and ionization sources has been investigated and applied to the non-target analysis of food packaging contaminants. Initially, the approach based on GC-time-of-flight (TOF) MS with electron ionization (EI) source allowed performing a library search and mass accurate measurements of selected ions. Then, a second analysis was performed using hybrid quadrupole (Q) TOF MS with an atmospheric pressure chemical ionization (APCI) source in order to search for the molecular ion or the protonated molecule and study the fragmentation behavior. This analytical strategy was applied to the analysis of four polypropylene/ethylene vinyl alcohol/polypropylene (PP/EVOH/PP) multilayer trays and one PP/Al foil/PP film, each one subjected to migration assays with the food simulants isooctane and Tenax®, in order to investigate its potential on the determination of migrant substances.

  2. Determination of glycated and acetylated hemoglobins in cord blood by time-of-flight mass spectrometry.

    Science.gov (United States)

    Dupont, Félix O; Gagnon, René; Ardilouze, Jean-Luc; Auray-Blais, Christiane

    2011-07-01

    The characterization of cord blood hemoglobin at the molecular level is a daunting challenge because hemoglobin F (HbF) and hemoglobin A (HbA) coexist in neonatal blood. We developed and validated a method using electrospray time-of-flight mass spectrometry (ES-TOF-MS) that measures, in a single analysis, relative levels of glycated and acetylated hemoglobin and allows the calculation of relative proportions of HbA, HbF(0), and HbF(1) in cord blood. Specific sections of acquired spectra were deconvoluted using a maximum entropy-based approach to true mass scale spectra. Mass precisions were less than 3 ppm with similar accuracies. Intra-interday precisions for α- and γ-chain glycation levels were 2.10%/3.72% and 2.75%/6.79%, respectively. The linearity of the α-chain glycation response was excellent (r(2) = 0.9990). We performed sample analysis on 39 cord blood specimens and found that the glycated α- and γ-chain levels were 2.27 ± 0.21% and 2.38 ± 0.29%, respectively, while the acetylated (G)γ and (A)γ-chain levels were 8.48 ± 0.53% and 7.14 ± 0.74%, respectively. We observed three types of HbF distinguishable by the intensities of γ-chain variants. Two-thirds of cord blood specimens were classified as HbF(I) with an intensity ratio (G)γ/(A)γ of 1.90 ± 0.12. For HbF(II) type (10/39 neonates), the intensity ratio of (G)γ/(A)γ was 3.71 ± 0.28. For three neonates with HbF(III), no (A)γ-chain was detected.

  3. Mass spectra and time-of-flight distributions of helium cluster beams

    Energy Technology Data Exchange (ETDEWEB)

    Buchenau, H.; Knuth, E.L.; Northby, J.; Toennies, J.P.; Winkler, C. (Max-Planck-Institut fuer Stroemungsforschung, Bunsenstrasse 10, D-3400 Goettingen, Federal Republic of Germany (DE))

    1990-06-01

    Liquid helium clusters are produced by expanding gaseous {sup 4} He into a vacuum from a cold source with temperatures between 5 and 20 K at stagnation pressures from {ital P}{sub 0} =8 to 20 bar and are studied by time-of-flight (TOF) and mass spectrometry. At low temperatures, {ital T}{sub 0} {lt}12 K, the mass spectra show several anomalies which can be attributed to pick-up of residual gases. At {ital T}{sub 0} {lt}10K, there is evidence for a very intense peak at {ital m}=16 amu which is attributed to He{sup +}{sub 4} . Depending on the temperatures, the TOF spectra reveal ions with three different velocities. These TOF observations are analyzed using isentropic lines in the known phase diagram of {sup 4} He, which take into account deviations from ideal gas behavior. Three qualitatively different expansion regimes are identified: (I) the expansion proceeds through a region on the high temperature side of the critical point, (II) the expansion passes through or near the critical point, and (III) the expansion passes through a region on the low temperature side of the critical point. The mass spectra, peak velocities and speed ratios, when analyzed with the aid of the phase diagram, indicate that (a) two of the TOF peaks are due to clusters, (b) the fastest cluster peak is due to clusters formed by condensation of gas phase atoms, and (c) the slowest cluster peak is due to either separation into two phases (regime II) or disintegration of a liquid phase (regime III). Measured conversions of initial enthalpy into free jet kinetic energy suggest that the cluster temperature undergoes a sharp drop to a very low temperature approaching 0 K at {ital T}{sub 0} {lt}6.5 K where the expansion isentrope intersects the liquid--vapor line upstream from the source orifice.

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

    Science.gov (United States)

    Glavin, Daniel P.; Dworkin, Jason P.

    2003-01-01

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

  5. A field-deployable, chemical ionization time-of-flight mass spectrometer

    Directory of Open Access Journals (Sweden)

    T. H. Bertram

    2011-07-01

    Full Text Available We constructed a new chemical ionization time-of-flight mass spectrometer (CI-TOFMS that measures atmospheric trace gases in real time with high sensitivity. We apply the technique to the measurement of formic acid via negative-ion proton transfer, using acetate as the reagent ion. A novel high pressure interface, incorporating two RF-only quadrupoles is used to efficiently focus ions through four stages of differential pumping before analysis with a compact TOFMS. The high ion-duty cycle (>20 % of the TOFMS combined with the efficient production and transmission of ions in the high pressure interface results in a highly sensitive (>300 ions s−1 pptv−1 formic acid instrument capable of measuring and saving complete mass spectra at rates faster than 10 Hz. We demonstrate the efficient transfer and detection of both bare ions and ion-molecule clusters, and characterize the instrument during field measurements aboard the R/V Atlantis as part of the CalNex campaign during the spring of 2010. The in-field short-term precision is better than 5 % at 1 pptv (pL/L, for 1-s averages. The detection limit (3 σ, 1-s averages of the current version of the CI-TOFMS, as applied to the in situ detection of formic acid, is limited by the magnitude and variability in the background determination and was determined to be 4 pptv. Application of the CI-TOFMS to the detection of other inorganic and organic acids, as well as the use of different reagent ion molecules (e.g. I, CF3O, CO3 is promising, as we have demonstrated efficient transmission and detection of both bare ions and their associated ion-molecule clusters.

  6. Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Sun, Jianghao; Baker, Andrew; Chen, Pei

    2011-09-30

    An ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine or ajmalicine core structure, plus methylated, oxidized and reduced species, were characterized. Common fragments and mass differences are described. It was shown that the use of IMS could provide another molecular descriptor, i.e. molecular shape by rotationally averaged collision cross-section; this is of great value for identification of constituents when reference materials are usually not available. Using the combination of high resolution (~40000) accurate mass measurement with time-aligned parallel (TAP) fragmentation, MS(E) (where E represents collision energy), ion mobility mass spectrometry (IMS) and UPLC chromatography, a total 55 indole alkaloids were characterized and a few new indole alkaloids are reported for the first time.

  7. Performance of matrix-assisted laser desorption-time of flight mass spectrometry for identification of clinical yeast isolates

    DEFF Research Database (Denmark)

    Rosenvinge, Flemming S; Dzajic, Esad; Knudsen, Elisa;

    2013-01-01

    Accurate and fast yeast identification is important when treating patients with invasive fungal disease as susceptibility to antifungal agents is highly species related. Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) provides a powerful tool with a clear potential...

  8. Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

    DEFF Research Database (Denmark)

    Bache, Nicolai; Rand, Kasper Dyrberg; Roepstorff, Peter;

    2008-01-01

    have now measured the level of hydrogen scrambling in a deprotonated, selectively labeled peptide using MALDI tandem time-of-flight mass spectrometry. Our results conclusively show that hydrogen scrambling is prevalent in the deprotonated peptide upon collisional activation. The amide hydrogens ((1)H...

  9. 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

  10. Time-of-flight mass spectrometry of laser exploding foil initiated PETN samples

    Science.gov (United States)

    Fajardo, Mario E.; Molek, Christopher D.; Fossum, Emily C.

    2017-01-01

    We report the results of time-of-flight mass spectrometry (TOFMS) measurements of the gaseous products of thin-film pentaerythritol tetranitrate [PETN, C(CH2NO3)4] samples reacting in vacuo. The PETN sample spots are produced by masked physical vapor deposition [A.S. Tappan, et al., AIP Conf. Proc. 1426, 677 (2012)] onto a first-surface aluminum mirror. A pulsed laser beam imaged through the soda lime glass mirror substrate converts the aluminum layer into a high-temperature high-pressure plasma which initiates chemical reactions in the overlying PETN sample. We had previously proposed [E.C. Fossum, et al., AIP Conf. Proc. 1426, 235 (2012)] to exploit differences in gaseous product chemical identities and molecular velocities to provide a chemically-based diagnostic for distinguishing between "detonation-like" and deflagration responses. Briefly: we expect in-vacuum detonations to produce hyperthermal (v˜10 km/s) thermodynamically-stable products such as N2, CO2, and H2O, and for deflagrations to produce mostly reaction intermediates, such as NO and NO2, with much slower molecular velocities - consistent with the expansion-quenched thermal decomposition of PETN. We observe primarily slow reaction intermediates (NO2, CH2NO3) at low laser pulse energies, the appearance of NO at intermediate laser pulse energies, and the appearance of hyperthemal CO/N2 at mass 28 amu at the highest laser pulse energies. However, these results are somewhat ambiguous, as the NO, NO2, and CH2NO3 intermediates persist and all species become hyperthermal at the higher laser pulse energies. Also, the purported CO/N2 signal at 28 amu may be contaminated by silicon ablated from the glass mirror substrate. We plan to mitigate these problems in future experiments by adopting the "Buelow" sample configuration which employs an intermediate foil barrier to shield the energetic material from the laser and the laser driven plasma [S.J. Buelow, et al., AIP Conf. Proc. 706, 1377 (2003)].

  11. Exact Mass Measurements for a-Allenic Alcohol by Atmospheric Pressure Chemical Ionization/Time-of-flight Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    何萍; 郭寅龙; 陈国强; 徐代旺; 麻生明

    2003-01-01

    The atmospheric pressure chemical ionization/time,of-flight mass speetrmtry (APEI/TOF-MS) was applied to determine the mass of five a.aIIenic alcohols via their vrotonated molecu.lar ions nslna Imsifive ion mode. Polyethylene Idycol (PEG) was used as the hlternal reference. All results were obtained under the resolution of about 5000 FWHM (full width at the half maximum). Solvent effects were studied and the satired results were obtained in acetonitrile. Comvared with the theoreflcal values, nun absolute errors were less thRn 1.0 mmu. The efTeets Of nozzle pote.Jldal, push pulse potential, pug pulse potentlai, puO bias potential and ic(lulsltion rate on exact mass determina/lon were also discussed. APCI/TOF.MS is proven to be a very semi/ire analytical technique and an alternative ionizafion mode in analytical technique lablle compounds with relatively weak polarity, such as a-allenic alcohol.

  12. Calibration of matrix-assisted laser desorption/ionization time-of-flight peptide mass fingerprinting spectra

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2007-01-01

    This chapter describes a number of aspects important for calibration of matrix-assisted laser desorption/ionization time-of-flight spectra prior to peptide mass fingerprinting searches. Both multipoint internal calibration and mass defect-based calibration is illustrated. The chapter describes ho...... potential internal calibrants, like tryptic autodigest peptides and keratin-related peptides, can be identified and used for high-precision calibration. Furthermore, the construction of project/user-specific lists of potential calibrants is illustrated....

  13. First on-line applications of multi-reflection time-of-flight mass separator at ISOLTRAP and the mass measurement of $^{82}$Zn

    CERN Document Server

    Wolf, Robert

    This thesis describes the implementation and first on-line application of a multi-reflection time-of-flight (MR-ToF) mass analyzer for high-resolution mass separation at the ISOLTRAP mass spectrometer at ISOLDE/CERN. On the one hand, the major objective was to improve ISOLTRAPs mass-measurement capabilities with respect to the ratio of delivered contaminating ions to ions of interest. On the other hand, the time necessary to purify wanted from unwanted species should be reduced as much as possible to enable access to even more exotic nuclei. The device has been set up, optimized and tested at the University of Greifswald before its move to ISOLTRAP. The achieved performance comprises mass resolving powers of up to 200000 reached at observation times of 30ms and a contamination suppression of about four orders of magnitude by use of a Bradbury-Nielsen gate. With the characteristics, it outperforms clearly the so far state-of-the-art purification method of a gas-filled Penning trap. To improve the utilization o...

  14. Identification of in vitro metabolites of ethylphenidate by liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

    OpenAIRE

    Negreira, Noelia; Erratico, Claudio; Nuijs, van, Alexander L.N.; Covaci, Adrian

    2016-01-01

    Abstract: Ethylphenidate is a new potent synthetic psychoactive drug, structurally related to methylphenidate. Using human liver microsomes and cytosol, we have investigated for the first time the Phase-I and Phase-II in vitro metabolism of ethylphenidate. The structure of the metabolites was elucidated by hybrid quadrupole time-of-flight mass spectrometry. Overall, seven Phase-I, but no Phase-II metabolites were detected. Ethylphenidate underwent hydroxylation forming two primary mono-hydrox...

  15. Molecule-Specific Imaging Analysis of Carcinogens in Breast Cancer Cells Using Time-of-Flight Secondary Ion Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Quong, J N; Knize, M G; Kulp, K S; Wu, K J

    2003-08-19

    Imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to study the localization of heterocyclic amines in MCF7 line of human breast cancer cells. The detection sensitivities of a model rodent mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were determined. Following an established criteria for the determination of status of freeze-fracture cells, the distribution of PhIP in the MCF7 cells are reported.

  16. Rapid Screening of Fluoroquinolones and Sulfonamides in Dairy Products Using Ultra Performance Liquid Chromatography Coupled to High Resolution Quadrupole Time-of-Flight Mass Spectrometry%超高效液相色谱-高分辨四级杆飞行时间质谱法快速筛查乳制品中磺胺类与氟喹诺酮类药物

    Institute of Scientific and Technical Information of China (English)

    孟哲; 石志红; 吕运开; 孙汉文

    2014-01-01

    利用超高效液相色谱-高分辨四级杆飞行时间质谱联用技术,建立了一种快速筛查乳制品中8种氟喹诺酮5种磺胺类药物及其4种乙酰化代谢物的新方法。采用乙腈-20%三氯乙酸溶液(100:1, V/V, pH 2.0)作溶剂和Oasis HLB固相萃取载体作吸附剂,实现了牛奶样品中17种目标物的同时提取和有效净化。利用MassLynx Chromlynx软件建立了这17种分析物的数据库。以Full Scan/MSE进行定性筛查和定量检测。4种代谢物在10~2000μg/L范围内和其它分析物在0.5~100μg/L范围内,其基质匹配内标校准曲线呈现良好的线性(R2>0.983)。氟喹诺酮的定量限为0.5~0.8μg/kg,磺胺类药物及代谢物的定量限为0.5~13.0μg/kg。在3个添加水平分析物的平均回收率(69%~92%)在职业分析化学家协会( AOAC)提出的允许范围之内,相对标准偏差均小于15%。本方法快速而灵敏,成功用于乳制品中抗生素及其代谢物的筛查、确认和定量分析。所研究的每种药物及代谢物残留均低于有关的最高残留限量( MRLs),但某些乳制品中其总残留量已超过最高残留限量。%A novel analytical method employing ultra performance liquid chromatography-quadrupole-time-of-flight mass spectrometry ( UPLC-Q-TOF/MS) was developed for the rapid screening of eight fluoroquinolones ( FQs) , five sulfonamides ( SAs) and four acetyled metabolites in dairy products. The simultaneous extraction and effective cleanup for seventeen target analytes in dairy product samples were achieved with acetonitrile-20% trichloroacetic acid (100:1, V/V, pH 2) as solvent and Oasis HLB SPE cartridges as sorbent. Using MassLynx Chromalynx Software, a database for 17 target analytes was established. Qualitatively screening and quantitative analysis were carried out by full scan/ MSE mode. The matrix-matched internal standard chalibration curves showed a good linearity (R2>0. 983) in the ranges of 10-2000 μg/L for metabolites and 0

  17. Structural elucidation of biologically active neomycin N-octyl derivatives in a regioisomeric mixture by means of liquid chromatography/ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Giera, Martin; de Vlieger, Jon S B; Lingeman, Henk; Irth, Hubertus; Niessen, Wilfried M A

    2010-05-30

    Structural elucidation of six regioisomers of mono-N-octyl derivatized neomycin is achieved using MS(n) (up to n = 4) on an ion trap time-of-flight (IT-TOF) instrument equipped with electrospray ionization. The mixture of six derivatized neomycin analogues was generated by reductive amination in a shotgun synthetic approach. In parallel to the liquid chromatography/mass spectrometry (LC/MS) detection, the antibacterial activity of the neomycin regioisomers was tested by post-column addition of buffer and bacterial inocula, subsequent microfractionation of the resulting mixture, incubation, and finally a chemiluminescence-based bioactivity measurement based on the production of bacterial ATP. The MS-based high-resolution screening approach described can be applied in medicinal chemistry to help in designing and producing new antibiotic substances, which is particularly challenging due to the high functionality of most antibiotic substances, therefore requiring advanced (hyphenated) separation and detection techniques for compound mixtures.

  18. Time-of-flight detector applied to mass measurements in Rare-RI Ring

    Energy Technology Data Exchange (ETDEWEB)

    Nagae, D., E-mail: nagae@tac.tsukuba.ac.jp [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Abe, Y. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Okada, S.; Ozawa, A. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Yamaguchi, T. [Department of Physics, Saitama University, Shimo-Okubo 255, Sakura-ku Saitama-shi, 338-8570 (Japan); Suzuki, H.; Moriguchi, T. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Ishibashi, Y. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Fukuoka, S.; Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T.; Suzaki, F.; Sato, K.; Furuki, H.; Ichihashi, N.; Miyazawa, S. [Department of Physics, Saitama University, Shimo-Okubo 255, Sakura-ku Saitama-shi, 338-8570 (Japan); Yamaguchi, Y.; Uesaka, T.; Wakasugi, M. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2013-12-15

    Highlights: • We have developed Time-of-flight detectors for the Rare-RI Ring. • Measurements to evaluate a time resolution and a detection efficiency have been performed using alpha particle and heavy ion beams. • Preliminary time resolution is about 130 ps and detection efficiency is about 56% for the heavy ion beams. -- Abstract: A large time-of-flight (TOF) detector has been developed for the Rare-RI Ring. This detector consists of a Multi Channel Plate (MCP) and a carbon foil. Secondary electrons from the carbon foil are transported to the MCP by crossed electric and magnetic fields. In order to cover the beam size of the ring, a large and thin carbon foil (100 mm × 50 mm{sup 2} and 60 μg/cm{sup 2}) is used as a sensitive material. The time resolution of σ≈130 ps, the detection efficiency about 56% and a position dependence of the TOF about 1 ns are obtained. A calculated position dependence of TOF adopting experimental (inhomogeneous) electric field and a homogeneous magnetic field is in agreement with the experimental one. These results suggest that the homogeneity of electric field is important to improve the time resolution in the large size detector.

  19. A multi-reflection time-of-flight mass spectrograph for short-lived and super-heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Schury, P., E-mail: schury@riken.jp [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); New Mexico State University, Dept. of Chem. and BioChem., Las Cruces, NM (United States); Wada, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ito, Y. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Naimi, S.; Sonoda, T. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Mita, H. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Aoyama Gakuin University, Sagamihara, Kanagawa (Japan); Okada, K. [Sophia University, Chiyoda-ku, Tokyo (Japan); Wollnik, H. [New Mexico State University, Dept. of Chem. and BioChem., Las Cruces, NM (United States); Chon, S. [KEK, Tsukuba, Ibaraki (Japan); Haba, H.; Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Koura, H. [Japan Atomic Energy Research Institute, Ibaraki (Japan); Miyatake, H. [KEK, Tsukuba, Ibaraki (Japan); Morimoto, K.; Morita, K. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan)

    2013-12-15

    Highlights: • Demonstrated very fast mass measurements with a multi-reflection time of flight mass spectrograph. • Mass resolving power of R{sub m}≈150,000 was achieved in 1.2-ms for A/q=39 ions. • Mass precision of (δm)/m =7.7×10{sup 8} was demonstrated for {sup 40}Ca{sub +}. • Effects of thermal and voltage instabilities are described. • Effects of thermal and voltage instabilities are described. -- Abstract: A multi-reflection time-of-flight (MRTOF) mass spectrograph has been implemented at RIKEN to provide high-precision mass measurements of very short-lived nuclei. Of particular interest are mass measurements of r-process nuclei and trans-uranium nuclei. In such nuclei, the MRTOF can perform on par with or better than traditional Penning trap systems. We demonstrate that the MRTOF-MS is capable of accurately attaining relative mass precision of δm/m<10{sup -7} and describe it’s utility with heavy, short-lived nuclei.

  20. Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

    Science.gov (United States)

    Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

    2013-01-01

    Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

  1. Headspace analysis of new psychoactive substances using a Selective Reagent Ionisation-Time of Flight-Mass Spectrometer

    OpenAIRE

    2014-01-01

    The rapid expansion in the number and use of new psychoactive substances presents a significant analytical challenge because highly sensitive instrumentation capable of detecting a broad range of chemical compounds in real-time with a low rate of false positives is required. A Selective Reagent Ionisation-Time of Flight-Mass Spectrometry (SRI-ToF-MS) instrument is capable of meeting all of these requirements. With its high mass resolution (up to m/Δm of 8000), the application of variations in...

  2. Derivatization of Dextran for Multiply Charged Ion Formation and Electrospray Ionization Time-of-Flight Mass Spectrometric Analysis

    Science.gov (United States)

    Tapia, Jesus B.; Hibbard, Hailey A. J.; Reynolds, Melissa M.

    2017-10-01

    We present the use of a simple, one-pot derivatization to allow the polysaccharide dextran to carry multiple positive charges, shifting its molecular weight distribution to a lower m/ z range. We performed this derivatization because molecular weight measurements of polysaccharides by mass spectrometry are challenging because of their lack of readily ionizable groups. The absence of ionizable groups limits proton abstraction and suppresses proton adduction during the ionization process, producing mass spectra with predominantly singly charged metal adduct ions, thereby limiting the detection of large polysaccharides. To address this challenge, we derivatized dextran T1 (approximately 1 kDa) by attaching ethylenediamine, giving dextran readily ionizable, terminal amine functional groups. The attached ethylenediamine groups facilitated proton adduction during the ionization process in positive ion mode. Using the low molecular weight dextran T1, we tracked the number of ethylenediamine attachments by measuring the mass shift from underivatized to derivatized dextran T1. Using electrospray ionization time-of-flight mass spectrometry, we observed derivatized dextran chains ranging from two to nine glucose residues with between one and four attachments/charges. Our success in shifting derivatized dextran T1 toward the low m/ z range suggests potential for this derivatization as a viable route for analysis of high molecular weight polysaccharides using electrospray ionization time-of-flight mass spectrometry. [Figure not available: see fulltext.

  3. Increasing throughput and information content for in vitro drug metabolism experiments using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer.

    Science.gov (United States)

    Castro-Perez, Jose; Plumb, Robert; Granger, Jennifer H; Beattie, Iain; Joncour, Karine; Wright, Andrew

    2005-01-01

    The field of drug metabolism has been revolutionized by liquid chromatography/mass spectrometry (LC/MS) applications with new technologies such as triple quadrupoles, ion traps and time-of-flight (ToF) instrumentation. Over the years, these developments have often relied on the improvements to the mass spectrometer hardware and software, which has allowed users to benefit from lower levels of detection and ease-of-use. One area in which the development pace has been slower is in high-performance liquid chromatography (HPLC). In the case of metabolite identification, where there are many challenges due to the complex nature of the biological matrices and the diversity of the metabolites produced, there is a need to obtain the most accurate data possible. Reactive or toxic metabolites need to be detected and identified as early as possible in the drug discovery process, in order to reduce the very costly attrition of compounds in late-phase development. High-resolution, exact mass measurement plays a very important role in metabolite identification because it allows the elimination of false positives and the determination of non-trivial metabolites in a much faster throughput environment than any other standard current methodology available to this field. By improving the chromatographic resolution, increased peak capacity can be achieved with a reduction in the number of co-eluting species leading to superior separations. The overall enhancement in the chromatographic resolution and peak capacity is transferred into a net reduction in ion suppression leading to an improvement in the MS sensitivity. To investigate this, a number of in vitro samples were analyzed using an ultra-performance liquid chromatography (UPLC) system, with columns packed with porous 1.7 mum particles, coupled to a hybrid quadrupole time-of-flight (ToF) mass spectrometer. This technique showed very clear examples for fundamental gains in sensitivity, chromatographic resolution and speed of

  4. Classification of stevia sweeteners in soft drinks using liquid chromatography and time-of-flight mass spectrometry.

    Science.gov (United States)

    Kakigi, Y; Suzuki, T; Icho, T; Uyama, A; Mochizuki, N

    2013-01-01

    The aim of this study was to develop a comprehensive analytical method for the characterisation of stevia sweeteners in soft drinks. By using LC and time-of-flight MS, we detected 30 steviol glycosides from nine stevia sweeteners. The mass spectral data of these compounds were applied to the analysis to determine steviol glycosides in nine soft drinks. On the basis of chromatographic data and principal-component analysis, these soft drinks were classified into three groups, and the soft drinks of each group, respectively, contained high-rebaudioside A extract, normal stevia extract or alfa-glucosyltransferase-treated stevia extract.

  5. Time-of-flight delay between oscillating neutrinos and gravitational waves from supernovae and the neutrino mass problem

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias]. E-mail: hermanjc@cbpf.br

    2001-04-01

    Neutrino oscillations during core bounce of a supernova collapse may induce detectable gravitational-wave bursts by the time they are trapped in the core. For large-scale distances the flavor changing neutrinos get delayed on its trip to earth while the gravitational waves they emit do not. Since the oscillation mechanism sets up the offset for both emissions, this fact yields in a time-of-flight delay between both the radiations that, whenever measured, could provide an inedit estimative of the absolute scale of neutrino masses. (author)

  6. Current status of matrix-assisted laser desorption ionisation-time of flight mass spectrometry in the clinical microbiology laboratory.

    Science.gov (United States)

    Kok, Jen; Chen, Sharon C A; Dwyer, Dominic E; Iredell, Jonathan R

    2013-01-01

    The integration of matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) into many clinical microbiology laboratories has revolutionised routine pathogen identification. MALDI-TOF MS complements and has good potential to replace existing phenotypic identification methods. Results are available in a more clinically relevant timeframe, particularly in bacteraemic septic shock. Novel applications include strain typing and the detection of antimicrobial resistance, but these are not widely used. This review discusses the technical aspects, current applications, and limitations of MALDI-TOF MS.

  7. Time-of-flight delay between oscillating neutrinos and gravitational waves from supernovae and the neutrino mass problem

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias]. E-mail: hermanjc@cbpf.br

    2001-04-01

    Neutrino oscillations during core bounce of a supernova collapse may induce detectable gravitational-wave bursts by the time they are trapped in the core. For large-scale distances the flavor changing neutrinos get delayed on its trip to earth while the gravitational waves they emit do not. Since the oscillation mechanism sets up the offset for both emissions, this fact yields in a time-of-flight delay between both the radiations that, whenever measured, could provide an inedit estimative of the absolute scale of neutrino masses. (author)

  8. Development of a time-of-flight mass spectrometer for ion desorption studies at HiSOR

    CERN Document Server

    Fujii, K; Nakashima, Y; Waki, S; Sardar, S A; Yasui, Y; Wada, S I; Sekitani, T; Tanaka, K

    2001-01-01

    We have developed a time-of-flight mass spectrometer which is now under operation at HiSOR storage ring for research of photon stimulated ion desorption (PSID). The employment of the pulsed high voltage method as a trigger allowed us to perform the investigations at a multi bunch operation of the storage ring. The performance of this spectrometer was evaluated by applying to the PSID measurements of PMMA (poly-methylmethacrylate) thin films. The results are compared with those obtained at Photon Factory by using pulsed synchrotron radiation in a single bunch operation. The capabilities of the apparatus for ion desorption studies are discussed.

  9. Direct Mass Measurements in the Light Neutron-Rich Region Using a Combined Energy and Time-of-Flight Technique

    Science.gov (United States)

    Pillai, C.; Swenson, L. W.; Vieira, D. J.; Butler, G. W.; Wouters, J. M.; Rokni, S. H.; Vaziri, K.; Remsberg, L. P.

    This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET(2) method. This technique has the advantage that many particle-bound nuclei, produced in fragmentation reactions can be measured simultaneously, independent of their N or Z. The main disadvantage of this approach is that both energy and time-of-flight must be measured precisely on an absolute scale. Although some mass walk with N and Z was observed in this experiment, these uncertainties were largely removed by extrapolating the smooth dependence observed for known nuclei which lie closer to the valley of (BETA)-stability. Mass measurements for several neutron-rich light nuclei ranging from C-17 to NE-26 have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of N-20 N and F-24 have been determined for the first time.

  10. Decomposition of cyclohexane ion induced by intense femtosecond laser fields by ion-trap time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Takao; Watanabe, Yusuke; Kanya, Reika [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamanouchi, Kaoru, E-mail: kaoru@chem.s.u-tokyo.ac.jp [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); NANOQUINE, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-01-14

    Decomposition of cyclohexane cations induced by intense femtosecond laser fields at the wavelength of 800 nm is investigated by ion-trap time-of-flight mass spectrometry in which cyclohexane cations C{sub 6}H{sub 12}{sup +} stored in an ion trap are irradiated with intense femtosecond laser pulses and the generated fragment ions are recorded by time-of-flight mass spectrometry. The various fragment ion species, C{sub 5}H{sub n}{sup +} (n = 7, 9), C{sub 4}H{sub n}{sup +} (n = 5–8), C{sub 3}H{sub n}{sup +} (n = 3–7), C{sub 2}H{sub n}{sup +} (n = 2–6), and CH{sub 3}{sup +}, identified in the mass spectra show that decomposition of C{sub 6}H{sub 12}{sup +} proceeds efficiently by the photo-irradiation. From the laser intensity dependences of the yields of the fragment ion species, the numbers of photons required for producing the respective fragment ions are estimated.

  11. Neutrino mass sensitivity by MAC-E-Filter based time-of-flight spectroscopy with the example of KATRIN

    CERN Document Server

    Steinbrink, Nicholas; Martin, Eric L; Robertson, R G Hamish; Zacher, Michael; Weinheimer, Christian

    2013-01-01

    The KATRIN experiment aims at a measurement of the neutrino mass with a 90 % C.L. sensitivity of 0.2 eV/c$^2$ by measuring the endpoint region of the tritium $\\beta$ decay spectrum from a windowless gaseous molecular tritium source using an integrating spectrometer of the MAC-E-Filter type. We discuss the idea of using the MAC-E-Filter in a time-of-flight mode (MAC-E-TOF) in which the neutrino mass is determined by a measurement of the electron time-of-flight (TOF) spectrum that depends on the neutrino mass. MAC-E-TOF spectroscopy here is a very sensitive method since the $\\beta$-electrons are slowed down to distinguishable velocities by the MAC-E-Filter. Their velocity depends strongly on their surplus energy above the electric retarding potential. Using MAC-E-TOF, a statistical sensitivity gain is expected. Because a small number of retarding-potential settings is sufficient for a complete measurement, in contrast to about 40 different retarding potentials used in the standard MAC-E-Filter mode, there is a ...

  12. Reduction of the jitter of single-flux-quantum time-to-digital converters for time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sano, K., E-mail: sano-kyosuke-cw@ynu.jp [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Muramatsu, Y.; Yamanashi, Y.; Yoshikawa, N. [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Zen, N.; Ohkubo, M. [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

    2014-09-15

    Highlights: • We proposed single-flux-quantum (SFQ) time-to-digital converters (TDCs) for TOF-MS. • SFQ TDC can measure time intervals between multiple signals with high-resolution. • SFQ TDC can directly convert the time intervals into binary data. • We designed two types of SFQ TDCs to reduce the jitter. • The jitter is reduced to less than 100 ps. - Abstract: We have been developing a high-resolution superconducting time-of-flight mass spectrometry (TOF-MS) system, which utilizes a superconducting strip ion detector (SSID) and a single-flux-quantum (SFQ) time-to-digital converter (TDC). The SFQ TDC can measure time intervals between multiple input signals and directly convert them into binary data. In our previous study, 24-bit SFQ TDC with a 3 × 24-bit First-In First-Out (FIFO) buffer was designed and implemented using the AIST Nb standard process 2 (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. In this study we reduce the jitter of the TDC by using two different approaches: one uses an on-chip clock generator with an on-chip low-pass filter for reducing the noise in the bias current, and the other uses a low-jitter external clock source at room temperature. We confirmed that the jitter is reduced to less than 100 ps in the latter approach.

  13. Time-of-flight secondary neutral & ion mass spectrometry using swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, L.; Meinerzhagen, F. [Universität Duisburg-Essen, Fakultät für Physik, D-47048 Duisburg (Germany); Bender, M.; Severin, D. [Gesellschaft für Schwerionenforschung GSI, D-64291 Darmstadt (Germany); Wucher, A., E-mail: andreas.wucher@uni-due.de [Universität Duisburg-Essen, Fakultät für Physik, D-47048 Duisburg (Germany)

    2015-12-15

    We report on a new time-of-flight (TOF) spectrometer designed to investigate sputtering phenomena induced by swift heavy ions in the electronic stopping regime. In this experiment, particular emphasis is put on the detection of secondary ions along with their emitted neutral counterparts in order to examine the ionization efficiency of the sputtered material. For the detection of neutral species, the system is equipped with a pulsed VUV laser for post-ionization of sputtered neutral atoms and molecules via single photon ionization at a wavelength of 157 nm (corresponding to 7.9 eV photon energy). For alignment purposes and in order to facilitate comparison to nuclear sputtering conditions, the system also includes a 5 keV Ar{sup +} ion beam directed to the same sample area. The instrument has been added to the M1-branch beam line at the German accelerator facility in Darmstadt (GSI) and was tested with 4.8 MeV/u Au{sup 26+} ions impinging onto various samples including metals, salts and organic films. It is found that secondary ion and neutral spectra obtained under both bombardment conditions can be acquired in an interleaved manner throughout a single accelerator pulse cycle, thus making efficient use of valuable beam time. In addition, the keV ion beam can be intermittently switched to dc mode between subsequent data acquisition windows and accelerator pulses in order to ensure reproducible surface conditions. For the case of a dynamically sputter cleaned metal surface, comparison of secondary ion and neutral signals obtained under otherwise identical instrumental conditions reveals a nearly identical ionization probability of atoms emitted under electronic and nuclear sputtering conditions.

  14. An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies.

    Science.gov (United States)

    Schowalter, Steven J; Chen, Kuang; Rellergert, Wade G; Sullivan, Scott T; Hudson, Eric R

    2012-04-01

    We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm ∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates. © 2012 American Institute of Physics

  15. Structural characterization of suppressor lipids by high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Rovillos, Mary Joy; Pauling, Josch Konstantin; Hannibal-Bach, Hans Kristian

    2016-01-01

    RATIONALE: Suppressor lipids were originally identified in 1993 and reported to encompass six lipid classes that enable Saccharomyces cerevisiae to live without sphingolipids. Structural characterization, using non-mass spectrometric approaches, revealed that these suppressor lipids are very long...... chain fatty acid (VLCFA)-containing glycerophospholipids with polar head groups that are typically incorporated into sphingolipids. Here we report, for the first time, the structural characterization of the yeast suppressor lipids using high-resolution mass spectrometry. METHODS: Suppressor lipids were...... isolated by preparative chromatography and subjected to structural characterization using hybrid quadrupole time-of-flight and ion trap-orbitrap mass spectrometry. RESULTS: Our investigation recapitulates the overall structural features of the suppressor lipids and provides an in-depth characterization...

  16. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Identification of Mycobacteria in Routine Clinical Practice: e24720

    National Research Council Canada - National Science Library

    Amel El Khéchine; Carine Couderc; Christophe Flaudrops; Didier Raoult; Michel Drancourt

    2011-01-01

    .... Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) has previously been proven to effectively identify mycobacteria grown in high-concentration inocula from collections...

  17. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics for comparison of caffeinated and decaffeinated coffee and its implications for Alzheimer's disease

    National Research Council Canada - National Science Library

    Chang, Kai Lun; Ho, Paul C

    2014-01-01

    ... to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee...

  18. Analysis of chlorophylls and their derivatives by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.

    Science.gov (United States)

    Suzuki, Toshiyuki; Midonoya, Hitoshi; Shioi, Yuzo

    2009-07-01

    The analysis of chlorophylls and their derivatives by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry is described. Four matrices-sinapinic acid, a-cyano-4-hydroxycinnnamic acid, terthiophene, and 3-aminoquinoline-were examined to determine optimal conditions for analysis of the molecular mass and structure of chlorophyll a as a representative chlorophyll. Among them, terthiophene was the most efficient without releasing metal ions, although it caused fragmentation of the phytol-ester linkage. Terthiophene was useful for the analyses of chlorophyll derivatives as well as porphyrin products such as 8-deethyl-8-vinyl-chlorophyll a, pheophorbide a, pyropheophorbide a, bacteriochlorophyll a esterified phytol, and protoporphyrin IX. The current method is suitable for rapid and accurate determination of the molecular mass and structure of chlorophylls and porphyrins.

  19. A data analysis method for isochronous mass spectrometry using two time-of-flight detectors at CSRe

    CERN Document Server

    Xu, Xing; Shuai, Peng; Chen, Rui-Jiu; Yan, Xin-Liang; Zhang, Yu-Hu; Yuan, You-Jin; Xu, Hu-Shan; Zhou, Xiao-Hong; Litvinov, Yuri A; Litvinov, Sergey; Tu, Xiao-Lin; Chen, Xiang-Cheng; Fu, Chao-Yi; Ge, Wen-Wen; Ge, Zhuang; Hu, Xue-Jing; Huang, Wen-Jia; Liu, Da-Wei; Xing, Yuan-Ming; Zeng, Qi; Zhang, Wei

    2016-01-01

    The concept of isochronous mass spectrometry (IMS) applying two time-of-flight (TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Recently, two TOF detectors have been installed at CSRe and the new working mode of the ring is under test. In this paper, a data analysis method for this mode is introduced and tested with a series of simulations. The results show that the new IMS method can significantly improve mass resolving power via the additional velocity information of stored ions. This improvement is especially important for nuclides with Lorentz factor $\\gamma$-value far away from the transition point $\\gamma _t$ of the storage ring CSRe.

  20. Direct Chemical Analysis of Solids by Laser Ablation in an Ion-Storage Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Klunder, G L; Grant, P M; Andresen, B D; Russo, R E

    2003-09-29

    A laser ablation/ionization mass spectrometer system is described for the direct analysis of solids, particles, and fibers. The system uses a quadrupole ion trap operated in an ion-storage (IS) mode, coupled with a reflectron time-of-flight mass spectrometer (TOF-MS). The sample is inserted radially into the ring electrode and an imaging system allows direct viewing and selected analysis of the sample. Measurements identified trace contaminants of Ag, Sn, and Sb in a Pb target with single laser-shot experiments. Resolution (m/{micro}m) of 1500 and detection limits of approximately 10 pg have been achieved with a single laser pulse. The system configuration and related operating principles for accurately measuring low concentrations of isotopes are described.

  1. Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Youngsu; Lee, Jonghee; Kim, Seongsoo [Agency for Defense Development, Daejeon (Korea, Republic of)

    2013-09-15

    The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field.

  2. Exploring the phase space of time of flight mass selected PtxY nanoparticles

    DEFF Research Database (Denmark)

    Masini, Federico; Hernandez-Fernandez, Patricia; Deiana, Davide

    2014-01-01

    Mass-selected nanoparticles can be conveniently produced using magnetron sputtering and aggregation techniques. However, numerous pitfalls can compromise the quality of the samples, e.g. double or triple mass production, dendritic structure formation or unpredicted particle composition. We stress...

  3. Multiresidue analysis of plant growth regulators in grapes by triple quadrupole and quadrupole-time of flight-based liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Oulkar, Dasharath P; Banerjee, Kaushik; Kulkarni, Sunil

    2011-01-01

    A selective and sensitive LC-MS/MS method is presented for simultaneous determination of 12 plant growth regulators, viz., indol-3-acetic acid, indol-3-butyric acid, kinetin, zeatin, 6-benzyl aminopurine, gibberellic acid, abscisic acid, chlormequat chloride, forchlorfenuron, paclobutrazole, daminozide, and 2,4-dichlorophenoxy acetic acid, in bud sprouts and grape berries. The sample preparation method involved extraction of homogenized sample (5 g) with 40 mL methanol (80%), and final determination was by LC-MS/MS in the multiple reaction monitoring (MRM) mode with time segmentation for quantification supported by complementary analysis by quadrupole-time of flight (Q-TOF) MS with targeted high-resolution MS/MS scanning for confirmatory identification based on accurate mass measurements. The recovery of the test compounds ranged within 90-107% with precision RSD less than 5% (n = 6). The method could be successfully applied in analyzing incurred residue samples, and the strength of accurate mass analysis could be utilized in identifying the compounds in cases where the qualifier MRM ions were absent or at an S/N less than 3:1 due to low concentrations.

  4. Sensitivity and fragmentation calibration of the time-of-flight mass spectrometer RTOF on board ESA's Rosetta mission

    Science.gov (United States)

    Gasc, Sébastien; Altwegg, Kathrin; Fiethe, Björn; Jäckel, Annette; Korth, Axel; Le Roy, Léna; Mall, Urs; Rème, Henri; Rubin, Martin; Hunter Waite, J.; Wurz, Peter

    2017-01-01

    The European Space Agency's Rosetta spacecraft, with the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) onboard, has been following and observing comet 67P/Churyumov-Gerasimenko since summer 2014. Prior to this period, and due to a technical failure also during this period, optimization and calibration campaigns have been conducted on ground with the Reflectron-type Time Of Flight (RTOF) mass spectrometer as a preparatory work for the analysis of data recorded during the science phase of the mission. In this work, we show the evolution of the performance of RTOF, and demonstrate and quantify the sensitivity and functionality of RTOF onboard Rosetta. We also present a fragmentation and sensitivity database for the most abundant molecules observed around the comet such as H2O, CO, CO2, as well as the noble gases.

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

    Science.gov (United States)

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

    2016-03-01

    Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the β-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R(2) > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of ≤ 2.5%. Additional and independent measurements of glycation of the α-subunit of hemoglobin are used to validate β-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.

  6. Urinary metabonomics of stomach cancer assessed by rapid resolution liquid chromatography/time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; REN Hui; JIANG Yang; GAO Yu-fei; LIU Shu-ying

    2013-01-01

    Background Stomach cancer is among the most commonly occurring malignancies worldwide.It would be beneficial to develop a urine-based assay whereby patients with undiagnosed stomach cancer could be screened and their cancer detected in the earliest stages.Methods A urinary metabonomics method based on ultra-performance liquid chromatography combined with quadruple time-of-flight mass spectrometry was used to analyze urine samples from patients with stomach cancer and healthy controls.Results Statistical analysis revealed a clear separation of patients and healthy controls using the aforementioned methodology.Some significantly changed metabolites were identified.Conclusions Use of the metabonomics method in patients with stomach cancer could effectively detect distinct changes in urinary metabolites and had the capacity to detect cancer; therefore,it may be a valuable tool in earlier diagnosis.Furthermore,the detection and identification of altered metabolites in the current study may help elucidate possible mechanisms involved in stomach cancer.

  7. Letter: A method for the chromatic aberration correction of a laser time of-flight mass analyzer.

    Science.gov (United States)

    Sysoeva, Elizaveta A; Sysoev, Alexander A

    2016-01-01

    The new ion-optical system of the laser time-of-flight (TOF) mass spectrometer on the basis of two tandem wedge-shape reflectors has been offered and implemented. A new method of correcting chromatic aberration by the ion energy was proposed that used a wire electrode unit with adjustable potentials. This unit allows one to adjust the local TOF of the ions in a narrow energy range ± (1-2)% within the total ion packet with an energy spread of ± 20%. The method reduces the duration of the ion packets by up to 1.5ns, which enables us to obtain the restriction of resolution at a level not worse than R ~ 10500 for a TOF ~35 µs. The aim of the project is to increase the separation of isobaric ions to improve the limit of detection of the laser TOF-MS for the analysis of high-purity samples.

  8. Potato glycoalkaloids in soil-optimising liquid chromatography-time-of-flight mass spectrometry for quantitative studies.

    Science.gov (United States)

    Jensen, Pia H; Juhler, René K; Nielsen, Nikoline J; Hansen, Thomas H; Strobel, Bjarne W; Jacobsen, Ole S; Nielsen, John; Hansen, Hans Christian B

    2008-02-22

    Potato glycoalkaloids are produced in high amounts in potato fields during the growth season and losses to soil potentially impact shallow groundwater and via tiles to fresh water ecosystems. A quantitative liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) method for determination and quantification of potato glycoalkaloids and their metabolites in aqueous soil extracts was developed. The LC-ESI-TOF-MS method had linearities up to 2000microg/L for alpha-solanine and alpha-chaconine and up to 760microg/L for solanidine. No matrix effect was observed, and the detection limits found were in the range 2.2-4.7microg/L. The method enabled quantification of the potato glycoalkaloids in environmental samples.

  9. Affinity labeling coupled with matrix assistant laser desorption tandem time of flight mass spectrometry for quantitative proteomies research

    Institute of Scientific and Technical Information of China (English)

    MENG Qingfang; ZHANG Yangjun; CAI Yun; QIAN Xiaohong

    2007-01-01

    A relative quantitative method for differential proteomics by cleavable isotope-coded atTmity tag (cICAT)and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-MS) was estab-lished. The accuracy and reproducibility of the method were evaluated by bovine serum albumin (BSA) digest as having a relative standard deviation of less than 30% and good reproducibility. The dynamic range was als0 evaluated by analyzing two mixtures of several standard proteins with dif-ferent concentration. The experimental results showed that in the dynamic range of 1:30, the quantitation error of the method was less than 30%. Although the quantitation error becomes very large when used beyond this range, it does not affect the derivation of information on the differential proteins. All the work provides an alternative method for differential proteomics analysis in biological samples from different origins.

  10. Feasibility of ultra-performance liquid chromatography-ion mobility-time-of-flight mass spectrometry in analyzing oxysterols.

    Science.gov (United States)

    Kylli, Petri; Hankemeier, Thomas; Kostiainen, Risto

    2017-03-03

    Oxysterols are oxygenated cholesterols that are important in many cell functions and they may also be indicative of certain diseases. The purpose of this work was to study the feasibility of ultra-performance liquid chromatography-ion mobility-time-of-flight mass spectrometry (UPLC-IM-TOFMS) using traveling wave cell in analyzing oxysterols and especially their isomers in biological samples. Oxysterols were analyzed as their p-toluenesulfonyl isocyanate derivatives, which improved the separation of isomeric oxysterols by ion mobility and ionization efficiency in the electrospray ionization step. The UPLC-IM-TOFMS method was shown to be fast and to provide good quantitative performance. The feasibility of the method was demonstrated in the analyses of oxysterols in fibroblast cell samples.

  11. Identification of Haemophilus influenzae and Haemophilus haemolyticus by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Bruin, J P; Kostrzewa, M; van der Ende, A; Badoux, P; Jansen, R; Boers, S A; Diederen, B M W

    2014-02-01

    Generally accepted laboratory methods that have been used for decades do not reliably distinguish between H. influenzae and H. haemolyticus isolates. H. haemolyticus strains are often incorrectly identified as nontypeable Haemophilus influenzae (NTHi). To distinguish H. influenzae from H. haemolyticus we have created a new database on the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) bio-typer 2 and compared the results with routine determination of Haemophilus (growth requirement for X and V factor), and multilocus sequence typing (MLST). In total we have tested 277 isolates, 244 H. influenzae and 33 H. haemolyticus. Using MLST as the gold standard, the agreement of MALDI-TOF MS was 99.6 %. MALDI-TOF MS allows reliable and rapid discrimination between H. influenzae and H. haemolyticus.

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

    Science.gov (United States)

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

    2016-03-01

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

  13. On Applicability of a Miniaturised Laser Ablation Time of Flight Mass Spectrometer for Trace Elements Measurements

    Directory of Open Access Journals (Sweden)

    Marek Tulej

    2012-01-01

    Full Text Available We present results from mass spectrometric analysis of NIST standard materials and meteoritic samples conducted by a miniaturised laser ablation mass spectrometer designed for space research. The mass analyser supports investigation with a mass resolution (/Δ ≈ 500–600 and dynamic range within seven decades. Nevertheless, to maintain an optimal spectral quality laser irradiances lower than ~1 GW/cm2 are applied so far which results in a spread of RSC values. To achieve the quantitative performance of mass analyser, various effects influencing RSC factors have to be investigated. In this paper we investigate influence of laser irradiance, sampling procedure and plasma chemistry on the quantitative elemental and isotopic analysis. The studies indicate necessity for accurate control of laser characteristics and acquisition procedure. A relatively low irradiance applied causes a negligible sample damage and allows for accumulation of large number of waveforms from one sample location. The procedure yields statistically well averaged data and allows a sensitive in-depth analysis. The quantitative analyses of isotopic composition can be performed with accuracy and precision better as 1% and 2%, for isotopic patterns of elements and clusters, respectively. The numerical integration methods would be preferred to achieve more accurate results. The measurements of Allende sample yield detection of Pb isotopic pattern, nevertheless cluster species are readily observed in spectrum and make the elemental analysis of other trace elements difficult due to isobaric interferences. These detections are of a considerable interest because of possible application of the instrument for in situ elemental and isotopic analysis and radiometric dating of solids.

  14. Accurate screening for synthetic preservatives in beverage using high performance liquid chromatography with time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiuqin; Zhang Feng; Sun Yanyan; Yong Wei [Institute of Food Safety, Chinese Academy of Inspection and Quarantine, Jia 3, Gaobeidian North Road, Beijing 100025 (China); Chu Xiaogang [Institute of Food Safety, Chinese Academy of Inspection and Quarantine, Jia 3, Gaobeidian North Road, Beijing 100025 (China)], E-mail: lixq_sypu@yahoo.com; Fang Yanyan; Zweigenbaum, Jerry [Agilent Technologies, Inc., 2850 Centerville Road, Wilmington, Delaware (United States)

    2008-02-11

    In this study, liquid chromatography time-of-flight mass spectrometry (HPLC/TOF-MS) is applied to qualitation and quantitation of 18 synthetic preservatives in beverage. The identification by HPLC/TOF-MS is accomplished with the accurate mass (the subsequent generated empirical formula) of the protonated molecules [M + H]+ or the deprotonated molecules [M - H]-, along with the accurate mass of their main fragment ions. In order to obtain sufficient sensitivity for quantitation purposes (using the protonated or deprotonated molecule) and additional qualitative mass spectrum information provided by the fragments ions, segment program of fragmentor voltages is designed in positive and negative ion mode, respectively. Accurate mass measurements are highly useful in the complex sample analyses since they allow us to achieve a high degree of specificity, often needed when other interferents are present in the matrix. The mass accuracy typically obtained is routinely better than 3 ppm. The 18 compounds behave linearly in the 0.005-5.0 mg.kg{sup -1} concentration range, with correlation coefficient >0.996. The recoveries at the tested concentrations of 1.0 mg.kg{sup -1}-100 mg.kg{sup -1} are 81-106%, with coefficients of variation <7.5%. Limits of detection (LODs) range from 0.0005 to 0.05 mg.kg{sup -1}, which are far below the required maximum residue level (MRL) for these preservatives in foodstuff. The method is suitable for routine quantitative and qualitative analyses of synthetic preservatives in foodstuff.

  15. A signature-based method to distinguish time-of-flight secondary-ion mass spectra from biological samples.

    Science.gov (United States)

    Quong, Judy N; Quong, Andrew A; Wu, Kuang Jen; Kercher, James R

    2005-11-01

    Time-Of-Flight Mass Spectrometry (TOF-SIMS) was used to determine elemental and biomolecular ions from isolated protein samples. We identified a set of 23 mass-to-charge ratio (m/z) peaks that represent signatures for distinguishing biological samples. The 23 peaks were identified by Singular Value Decomposition (SVD) and Canonical Analysis (CA) to find the underlying structure in the complex mass-spectra data sets. From this modified data, SVD was used to identify sets of m/z peaks, and we used these patterns from the TOF-SIMS data to predict the biological source from which individual mass spectra were generated. The signatures were validated using an additional data set different from the initial training set used to identify the signatures. We present a simple method to identify multiple variables required for sample classification based on mass spectra that avoids overfit. This is important in a variety of studies using mass spectrometry, including the ability to identify proteins in complex mixtures and for the identification of new biomarkers.

  16. Shotgun Lipidomics by Sequential Precursor Ion Fragmentation on a Hybrid Quadrupole Time-of-Flight Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    Brigitte Simons

    2012-02-01

    Full Text Available Shotgun lipidomics has evolved into a myriad of multi-dimensional strategies for molecular lipid characterization, including bioinformatics tools for mass spectrum interpretation and quantitative measurements to study systems-lipidomics in complex biological extracts. Taking advantage of spectral mass accuracy, scan speed and sensitivity of improved quadrupole linked time-of-flight mass analyzers, we developed a bias-free global lipid profiling acquisition technique of sequential precursor ion fragmentation called MS/MSALL. This generic information-independent tandem mass spectrometry (MS technique consists of a Q1 stepped mass isolation window through a set mass range in small increments, fragmenting and recording all product ions and neutral losses. Through the accurate MS and MS/MS information, the molecular lipid species are resolved, including distinction of isobaric and isomeric species, and composed into more precise lipidomic outputs. The method demonstrates good reproducibility and at least 3 orders of dynamic quantification range for isomeric ceramides in human plasma. More than 400 molecular lipids in human plasma were uncovered and quantified in less than 12 min, including acquisitions in both positive and negative polarity modes. We anticipate that the performance of sequential precursor ion fragmentation both in quality and throughput will lead to the uncovering of new avenues throughout the biomedical research community, enhance biomarker discovery and provide novel information target discovery programs as it will prospectively shed new insight into affected metabolic and signaling pathways.

  17. Accurate screening for synthetic preservatives in beverage using high performance liquid chromatography with time-of-flight mass spectrometry.

    Science.gov (United States)

    Li, Xiu Qin; Zhang, Feng; Sun, Yan Yan; Yong, Wei; Chu, Xiao Gang; Fang, Yan Yan; Zweigenbaum, Jerry

    2008-02-11

    In this study, liquid chromatography time-of-flight mass spectrometry (HPLC/TOF-MS) is applied to qualitation and quantitation of 18 synthetic preservatives in beverage. The identification by HPLC/TOF-MS is accomplished with the accurate mass (the subsequent generated empirical formula) of the protonated molecules [M+H]+ or the deprotonated molecules [M-H]-, along with the accurate mass of their main fragment ions. In order to obtain sufficient sensitivity for quantitation purposes (using the protonated or deprotonated molecule) and additional qualitative mass spectrum information provided by the fragments ions, segment program of fragmentor voltages is designed in positive and negative ion mode, respectively. Accurate mass measurements are highly useful in the complex sample analyses since they allow us to achieve a high degree of specificity, often needed when other interferents are present in the matrix. The mass accuracy typically obtained is routinely better than 3 ppm. The 18 compounds behave linearly in the 0.005-5.0mg.kg(-1) concentration range, with correlation coefficient >0.996. The recoveries at the tested concentrations of 1.0mg.kg(-1)-100mg.kg(-1) are 81-106%, with coefficients of variation preservatives in foodstuff. The method is suitable for routine quantitative and qualitative analyses of synthetic preservatives in foodstuff.

  18. Biological tissue imaging with a hybrid cluster SIMS quadrupole time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Carado, A. [Pennsylvania State University, 104 Chemistry Building, University Park, PA (United States)], E-mail: ajc161@psu.edu; Kozole, J.; Passarelli, M.; Winograd, N. [Pennsylvania State University, 104 Chemistry Building, University Park, PA (United States); Loboda, A. [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ontario, CA (United States); Bunch, J. [Centre for Analytical Sciences, University of Sheffield, Sheffield S3 7HF (United Kingdom); Wingate, J. [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ontario, CA (United States); Hankin, J.; Murphy, R. [University of Colorado at Denver and Health Science Center, 12801 East 17th Avenue, Aurora, CO (United States)

    2008-12-15

    A 20 keV C{sub 60}{sup +} ion source was mounted onto a commercial MALDI/electrospray orthogonal ToF mass spectrometer. Cross-sectional mouse brain and lung slices between 5 and 10 {mu}m prepared by cryostat sectioning were successfully imaged using a DC C{sub 60}{sup +} primary ion beam at a spot size of 100 {mu}m. Analysis was performed at room temperature following vacuum drying. An abundance of ions were mapped in all samples, many whose identity can only be found using the MS/MS functionality. We have successfully identified and imaged localizations of diacylglycerol (DAG) ions - 1-palmitoyl-2-oleoyl-glycerol (m/z{sup +} 577.5) and 1,2-dioleoyl-glycerol (m/z{sup +} 603.5) - in lung tissue. The mouse brain slice revealed strong, distinct localizations of many ions revealing the potential for this technique for biological imaging. Ions throughout the mass range of m/z{sup +} 50-800 were collected in sufficient quantities to permit unambiguous chemical mapping. Mass resolutions of 12,000 or greater were routinely obtained allowing for more accurate ion mapping than typically seen with ToF-SIMS image analysis.

  19. First online multireflection time-of-flight mass measurements of isobar chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy

    Science.gov (United States)

    Schury, P.; Wada, M.; Ito, Y.; Kaji, D.; Arai, F.; MacCormick, M.; Murray, I.; Haba, H.; Jeong, S.; Kimura, S.; Koura, H.; Miyatake, H.; Morimoto, K.; Morita, K.; Ozawa, A.; Rosenbusch, M.; Reponen, M.; Söderström, P.-A.; Takamine, A.; Tanaka, T.; Wollnik, H.

    2017-01-01

    Using a multireflection time-of-flight mass spectrograph located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several α -decaying heavy nuclei were directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectilelike and targetlike particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 204Fr-204Rn-204At-204Po , 205Fr-205Rn-205At-205Po-205Bi , and 206Fr-206Rn-206At , were observed. Precision atomic mass values were determined for Fr-206204, Rn,205204, and At,205204. Identifications of 205Bi, Po,205204, 206Rn, and 206At were made with N ≲10 detected ions, representing the next step toward use of mass spectrometry to identify exceedingly low-yield species such as superheavy element ions.

  20. Microfluidic cell culture and metabolism detection with electrospray ionization quadrupole time-of-flight mass spectrometer.

    Science.gov (United States)

    Gao, Dan; Wei, Huibin; Guo, Guang-Sheng; Lin, Jin-Ming

    2010-07-01

    A novel method for the characterization of drug metabolites was developed by integrating chip-based solid-phase extraction (SPE) with an online electrospray ionization quadrupole time-of-fight mass spectrometer (ESI-Q-TOF-MS). The integrated microfluidic device was composed of circular chambers for cell culture and straight microchannels with shrink ends to pack the solid-phase material for sample cleanup and concentration prior to mass analysis. By connecting the two separated microchannels with polyethylene tubes, drug metabolism studies related to functional units, including cell culture, metabolism generation, sample pretreatment, and detection, were all integrated into the microfluidic device. To verify the feasibility of a drug metabolism study on the microfluidic device, the metabolism of vitamin E in human lung epithelial A549 cells was studied. The metabolites were successfully detected by online ESI-Q-TOF-MS with high sensitivity and short analysis time (8 min). By integrating several parallel channels, the desalting and concentration process could be simultaneously achieved. The total sample pretreatment time only needed about 15 min, and solvent consumption could be reduced to less than 100 microL. All this demonstrated that the developed microfluidic device could be a potential useful tool for cellular drug metabolism research.

  1. Cluster SIMS with a hybrid quadrupole time-of-flight mass spectrometer

    Science.gov (United States)

    Carado, A.; Kozole, J.; Passarelli, M.; Winograd, N.; Loboda, A.; Wingate, J.

    2008-12-01

    The new physics associated with cluster SIMS, i.e. reduced chemical damage enabling 3D dynamic imaging, and increased ion yields from organics samples, suggests that cluster sources may be suitable for use on commercial MALDI/electrospray (ESI) instruments. In efforts to investigate this approach to secondary ion analysis, a 20 keV C 60+ primary ion source by Ionoptika Ltd. was fitted to a commercial LC/MS/MS instrument; the QSTAR ® XL system by Applied Biosystems/MDS Sciex. This instrument is capable of MS/MS, ion trapping, chemical imaging, and utilizes an orthogonal ToF, enabling use of a DC primary ion beam for imaging and data collection. The system employs high nitrogen pressure, typically several millitorr, in the sample region, as opposed to large extraction voltages, to facilitate the transmission of the secondary ions to the ToF region. In these initial experiments, it was demonstrated that ion signal generated by C 60+ bombardment can be enhanced by trapping in the collision cell and that secondary ions can fragment via collision induced dissociation (CID) to yield MS/MS information. In ToF-MS mode, efficiencies are comparable with pulsed primary beam ToF-SIMS instruments. Mass resolution of over 12,000 is routinely observed with mass accuracy in the 2 ppm range, which has important implications in accurate ion mapping in imaging mode.

  2. Cluster SIMS with a hybrid quadrupole time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Carado, A. [Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802 (United States)], E-mail: ajc161@psu.edu; Kozole, J.; Passarelli, M.; Winograd, N. [Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802 (United States); Loboda, A.; Wingate, J. [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ontario, CA (United States)

    2008-12-15

    The new physics associated with cluster SIMS, i.e. reduced chemical damage enabling 3D dynamic imaging, and increased ion yields from organics samples, suggests that cluster sources may be suitable for use on commercial MALDI/electrospray (ESI) instruments. In efforts to investigate this approach to secondary ion analysis, a 20 keV C{sub 60}{sup +} primary ion source by Ionoptika Ltd. was fitted to a commercial LC/MS/MS instrument; the QSTAR XL system by Applied Biosystems/MDS Sciex. This instrument is capable of MS/MS, ion trapping, chemical imaging, and utilizes an orthogonal ToF, enabling use of a DC primary ion beam for imaging and data collection. The system employs high nitrogen pressure, typically several millitorr, in the sample region, as opposed to large extraction voltages, to facilitate the transmission of the secondary ions to the ToF region. In these initial experiments, it was demonstrated that ion signal generated by C{sub 60}{sup +} bombardment can be enhanced by trapping in the collision cell and that secondary ions can fragment via collision induced dissociation (CID) to yield MS/MS information. In ToF-MS mode, efficiencies are comparable with pulsed primary beam ToF-SIMS instruments. Mass resolution of over 12,000 is routinely observed with mass accuracy in the 2 ppm range, which has important implications in accurate ion mapping in imaging mode.

  3. Identification and Classification of Rhizobia by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry.

    Science.gov (United States)

    Jia, Rui Zong; Zhang, Rong Juan; Wei, Qing; Chen, Wen Feng; Cho, Il Kyu; Chen, Wen Xin; Li, Qing X

    Mass spectrometry (MS) has been widely used for specific, sensitive and rapid analysis of proteins and has shown a high potential for bacterial identification and characterization. Type strains of four species of rhizobia and Escherichia coli DH5α were employed as reference bacteria to optimize various parameters for identification and classification of species of rhizobia by matrix-assisted laser desorption/ionization time-of-flight MS (MALDI TOF MS). The parameters optimized included culture medium states (liquid or solid), bacterial growth phases, colony storage temperature and duration, and protein data processing to enhance the bacterial identification resolution, accuracy and reliability. The medium state had little effects on the mass spectra of protein profiles. A suitable sampling time was between the exponential phase and the stationary phase. Consistent protein mass spectral profiles were observed for E. coli colonies pre-grown for 14 days and rhizobia for 21 days at 4°C or 21°C. A dendrogram of 75 rhizobial strains of 4 genera was constructed based on MALDI TOF mass spectra and the topological patterns agreed well with those in the 16S rDNA phylogenetic tree. The potential of developing a mass spectral database for all rhizobia species was assessed with blind samples. The entire process from sample preparation to accurate identification and classification of species required approximately one hour.

  4. Qualitative and quantitative analysis of the chemical constituents in Mahuang-Fuzi-Xixin decoction based on high performance liquid chromatography combined with time-of-flight mass spectrometry and triple quadrupole mass spectrometers.

    Science.gov (United States)

    Sun, Qihui; Cao, Hongjie; Zhou, Yanyan; Wang, Xu; Jiang, Haiqiang; Gong, Lili; Yang, Yong; Rong, Rong

    2016-11-01

    High-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF/MS) and high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-QQQ/MS/MS) were utilized to clarify the chemical constituents of Mahuang-Fuzi-Xixin Decoction. There are 52 compounds, including alkaloids, amino acids and organic acids were identified or tentatively characterized by their characteristic high resolution mass data by HPLC-QQQ/MS/MS. In the subsequent quantitative analysis, 10 constituents, including methyl ephedrine, aconine, songrine, fuziline, neoline, talatisamine, chasmanine, benzoylmesaconine, benzoylaconine and benzoylhypaconine were simultaneously determined by HPLC-QQQ/MS/MS with multiple reaction monitoring mode. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.9992). The relative standard deviations (RSD) of inter- and intra-day precisions were chemical constituents studying, including identification and quantification of Mahuang-Fuzi-Xixin decoction. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Yeast expression proteomics by high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Walther, Tobias C; Olsen, Jesper Velgaard; Mann, Matthias

    2010-01-01

    -translational controls contribute majorly to regulation of protein abundance, for example in heat shock stress response. The development of new sample preparation methods, high-resolution mass spectrometry and novel bioinfomatic tools close this gap and allow the global quantitation of the yeast proteome under different...... conditions. Here, we provide background information on proteomics by mass-spectrometry and describe the practice of a comprehensive yeast proteome analysis....

  6. Matrix-assisted laser desorption/ionisation, time-of-flight mass spectrometry in genomics research.

    Directory of Open Access Journals (Sweden)

    Jiannis Ragoussis

    2006-07-01

    Full Text Available The beginning of this millennium has seen dramatic advances in genomic research. Milestones such as the complete sequencing of the human genome and of many other species were achieved and complemented by the systematic discovery of variation at the single nucleotide (SNP and whole segment (copy number polymorphism level. Currently most genomics research efforts are concentrated on the production of whole genome functional annotations, as well as on mapping the epigenome by identifying the methylation status of CpGs, mainly in CpG islands, in different tissues. These recent advances have a major impact on the way genetic research is conducted and have accelerated the discovery of genetic factors contributing to disease. Technology was the critical driving force behind genomics projects: both the combination of Sanger sequencing with high-throughput capillary electrophoresis and the rapid advances in microarray technologies were keys to success. MALDI-TOF MS-based genome analysis represents a relative newcomer in this field. Can it establish itself as a long-term contributor to genetics research, or is it only suitable for niche areas and for laboratories with a passion for mass spectrometry? In this review, we will highlight the potential of MALDI-TOF MS-based tools for resequencing and for epigenetics research applications, as well as for classical complex genetic studies, allele quantification, and quantitative gene expression analysis. We will also identify the current limitations of this approach and attempt to place it in the context of other genome analysis technologies.

  7. Carbapenemase Activity Detection by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry ▿

    Science.gov (United States)

    Hrabák, Jaroslav; Walková, Radka; Študentová, Vendula; Chudáčková, Eva; Bergerová, Tamara

    2011-01-01

    Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is used for the determination of molecular weights of different chemical compounds. We describe here the use of MALDI-TOF mass spectrometry to detect a carbapenem antibiotic, meropenem, and its degradation products. Buffered meropenem solution (0.1 mM Tris-HCl, pH 6.8) was mixed with an overnight culture of bacteria. After 3-h incubation, the reaction mixture was centrifuged, and the supernatant was analyzed by MALDI-TOF mass spectrometry. The presence or absence of peaks representing meropenem and its sodium salts was crucial. The average turnaround time of this test, considering the use of overnight culture, is 4 h. We validated this method for the detection of resistance to carbapenems in Enterobacteriaceae and Pseudomonas aeruginosa mediated by carbapenemase production. A total of 124 strains, including 30 carbapenemase-producing strains, were used in the study. The sensitivity of this method is 96.67%, with a specificity of 97.87%. Our results demonstrate the ability of this method to routinely detect carbapenemases in Enterobacteriaceae and Pseudomonas spp. in laboratories. This assay is comparable with a labor-intensive imipenem-hydrolyzing spectrophotometric assay that is a reference method for the detection of carbapenemase. As demonstrated here, MALDI-TOF mass spectrometry may be used in microbiological laboratories not only for microbial identification but also for other applications, such as studies of mechanisms of antibiotic resistance. PMID:21775535

  8. Assessment of dispersive liquid-liquid microextraction conditions for gas chromatography time-of-flight mass spectrometry identification of organic compounds in honey.

    Science.gov (United States)

    Moniruzzaman, M; Rodríguez, I; Rodríguez-Cabo, T; Cela, R; Sulaiman, S A; Gan, S H

    2014-11-14

    The suitability of the dispersive liquid-liquid microextraction (DLLME) technique for gas chromatography (GC) characterization of minor organic compounds in honey samples is evaluated. Under optimized conditions, samples were pre-treated by liquid-liquid extraction with acetonitrile followed by DLLME using carbon tetrachloride (CCl4, 0.075 mL) as extractant. The yielded settled phase was analyzed by GC using high resolution time-of-flight (TOF) mass spectrometry (MS). The whole sample preparation process is completed in approximately 10 min, with a total consumption of organic solvents below 4 mL, relative standard deviations lower than 12% and with more than 70 organic compounds, displaying linear retention index in the range from 990 to 2900, identified in the obtained extracts. In comparison with HS SPME extraction, higher peak intensities were attained for most volatile and semi-volatile compounds amenable to both extraction techniques. Furthermore, other species such as highly polar and water soluble benzene acids, long chain fatty acids, esters and flavonoids, which are difficult to concentrate by HS SPME, could be identified in DLLME extracts. Some of the compounds identified in DLLME extracts have been proposed as useful for samples classification and/or they are recognized as markers of honeys from certain geographic areas.

  9. First Online Mass Measurements of Isobar Chains via Multi-Reflection Time-of-Flight Mass Spectrograph Coupled with GARIS-II

    CERN Document Server

    Schury, P; Ito, Y; Kaji, D; Soderstrom, P-A; Takamine, A; Arai, F; Haba, H; Jeong, S; Kimura, S; Koura, H; Miyatake, H; Morimoto, K; Morita, K; Ozawa, A; Reponen, M; Sonoda, T; Tanaka, T; Wollnik, H

    2015-01-01

    Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several heavy nuclei have been directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectile-like and target-like particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were observed. Precision atomic mass values were determined for 205,206Fr, 201At, and 201Po.

  10. Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicines

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fei Chen; Hai-Tang Wu; Guang-Guo Tan; Zhen-Yu Zhu; Yi-Feng Chai

    2011-01-01

    With the expansion of herbal medicine (HM) market, the issue on how to apply up-to- date analytical tools on qualitative analysis of HMs to assure their quality, safety and efficacy has been arousing great attention. Due to its inherent characteristics of accurate mass measurements and multiple stages analysis, the integrated strategy of liquid chromatography (LC) coupled with time-of-flight mass spectrometry (TOF-MS) and ion trap mass spectrometry (IT-MS) is well-suited to be performed as qualitative analysis tool in this field. The purpose of this review is to provide an overview on the potential of this integrated strategy, including the review of general features of LC-IT-MS and LC-TOF-MS, the advantages of their combination, the common procedures for structure elucidation, the potential of LC-hybrid-IT-TOF/MS and also the summary and discussion of the applications of the integrated strategy for HM qualitative analysis (2006-2011). The advantages and future developments of LC coupled with IT and TOF-MS are highlighted.

  11. Qualitative analysis of halogenated organic contaminants in American eel by gas chromatography/time-of-flight mass spectrometry.

    Science.gov (United States)

    Byer, Jonathan D; Pacepavicius, Grazina; Lebeuf, Michel; Brown, R Stephen; Backus, Sean; Hodson, Peter V; Alaee, Mehran

    2014-12-01

    Target compound analysis with scanning mass spectrometers such as quadrupole or magnetic sector instruments is used extensively in environmental chemistry because of the selectivity, sensitivity, and robustness. Yet, target compound analysis selectively ignores the majority of compounds present in a sample, especially in complex matrices like fish. In this study, time-of-flight mass spectrometry was used to screen for and identify halogenated compounds in American eels (Anguilla rostrata). Individual and then pooled eel samples were analysed using electron ionization and electron capture negative ionization (ECNI) modes. Eels were differentiated by principal component analysis of chemical profiles and were grouped corresponding to their capture location, all with a single instrument injection per sample. Bromine containing compounds were further investigated by taking advantage of the selectivity of ECNI by utilizing the Br(-) ion m/z 79 and 81. A total of 51 brominated compounds were detected and their identities were attempted by authentic standards, library searching, and/or chemical formula prediction based on accurate mass measurements. Several PBDEs were identified in the samples, and the majority of the non-PBDEs identified were bromophenols, bromoanisoles, and bromobenzenes. These classes of compounds are synthesized for use in flame retardant production either as intermediates or as final products. However, their occurrence in eels was most likely the result of metabolism or break-down products of high production volume flame retardants like polybrominated diphenyl ethers and bromophenoxy compounds. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  12. Quantification of grafted poly(ethylene glycol)-silanes on silicon by time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Norrman, K; Papra, A; Kamounah, F S; Gadegaard, N; Larsen, N B

    2002-07-01

    Silicon grafted monodisperse poly(ethylene glycol) (PEG) silanes with various PEG chain lengths and mixtures of these were systematically analyzed with static time-of-flight secondary ion mass spectrometry (TOF-SIMS). The mass spectra show differences in the various relative signal intensities, an observation that was used to elucidate important aspects of the grafting process. The relationship between PEG-silane fragment ion abundances and Si(+) ion abundances were used to (i) qualitatively describe layer thicknesses of grafted mixtures of PEG-silanes on silicon, (ii) construct a calibration curve from which PEG chain length (or molecular mass) can be determined and (iii) quantitatively determine surface mixture compositions of grafted monodisperse PEG-silanes of different chain lengths (3, 7 and 11 PEG units). The results suggest that discrimination does take place in the adsorption process. The PEG-silane with the shorter PEG chain is discriminated for mixtures containing PEG3-silane, whereas the PEG-silane with the longer PEG chain is discriminated in PEG7/PEG11-silane mixtures. The origin of this difference in adsorption behavior is not well understood. Aspects of the grafting process and the TOF-SIMS analyses are discussed.

  13. New Potential Biomarker for Methasterone Misuse in Human Urine by Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry

    Science.gov (United States)

    Zhang, Jianli; Lu, Jianghai; Wu, Yun; Wang, Xiaobing; Xu, Youxuan; Zhang, Yinong; Wang, Yan

    2016-01-01

    In this study, methasterone urinary metabolic profiles were investigated by liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF-MS) in full scan and targeted MS/MS modes with accurate mass measurement. A healthy male volunteer was asked to take the drug and liquid–liquid extraction was employed to process urine samples. Chromatographic peaks for potential metabolites were hunted out with the theoretical [M − H]− as a target ion in a full scan experiment and actual deprotonated ions were studied in targeted MS/MS experiment. Fifteen metabolites including two new sulfates (S1 and S2), three glucuronide conjugates (G2, G6 and G7), and three free metabolites (M2, M4 and M6) were detected for methasterone. Three metabolites involving G4, G5 and M5 were obtained for the first time in human urine samples. Owing to the absence of helpful fragments to elucidate the steroid ring structure of methasterone phase II metabolites, gas chromatography mass spectrometry (GC-MS) was employed to obtain structural information of the trimethylsilylated phase I metabolite released after enzymatic hydrolysis and the potential structure was inferred using a combined MS method. Metabolite detection times were also analyzed and G2 (18-nor-17β-hydroxymethyl-2α, 17α-dimethyl-androst-13-en-3α-ol-ξ-O-glucuronide) was thought to be new potential biomarker for methasterone misuse which can be detected up to 10 days. PMID:27669235

  14. Mass measurements of {sup 238}U-projectile fragments for the first time with a multiple-reflection time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Jens

    2016-07-01

    Mass measurements of short-lived uranium projectile fragments were performed for the first time with a Multiple-Reflexion-Time-of-Flight Mass Spectrometer (MR-TOF-MS). A major part of this doctoral work was a novel development of a data analysis method for the MR-TOF-MS mass measurements of exotic nuclei at the fragment separator FRS at GSI. The developed method was successfully applied to the data obtained from two pilot experiments with the MR-TOF-MS at the FRS in 2012 and 2014. A substantial upgrade of the experimental setup of the MR-TOF-MS was also performed in the frame work of this doctoral thesis after the first run. In the experiments projectile fragments were created with 1000 MeV/u {sup 238}U ions in a Be/Nb target at the entrance of the in-flight separator FRS. The exotic nuclei were spatially separated, energy bunched and slowed down with the ion-optical system of the FRS combined with monoenergetic and homogeneous degraders. At the final focal plane of the FRS the fragments were completely slowed down and thermalized in a cryogenic stopping cell (CSC) filled with 3-5 mg/cm{sup 2} pure helium gas. The exotic nuclei were fast extracted from the CSC to enable mass measurements of very short-lived fragments with the MR-TOF-MS. The achievement of this goal was successfully demonstrated with the mass measurement of {sup 220}Ra ions with a half-life of 17.9 ms and 11 detected events. The mass measurements of the isobars {sup 211}Fr, {sup 211}Po and {sup 211}Rn have clearly demonstrated the scientific potential of the MR-TOF-MS for the investigation of exotic nuclei and the power of the data analysis system. Difficult measurements with overlapping mass distributions with only a few counts in the measured spectra were the challenge for the new data analysis method based on the maximum likelihood method. The drifts during the measurements were corrected with the developed time-resolved calibration method. After the improvements of the setup as a consequence of

  15. Metabolism of olaquindox in rat liver microsomes: structural elucidation of metabolites by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

    Science.gov (United States)

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

    2008-04-01

    Olaquindox (N-(2-hydroxyethyl)-3-methyl-2-quinoxalincarboxamide-1,4-dioxide) is a growth-promoting feed additive for food-producing animals. Its toxicity is closely related to the metabolism. The complete metabolic pathways of olaquindox are not revealed. To improve studies of the metabolism and toxicity of olaquindox, its biotransformation in rat liver microsomes and the structure of its metabolites using high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF) were investigated. When olaquindox was incubated with an NADPH-generating system and rat liver microsomes, ten metabolites (M1-M10) were detected. The structures of these metabolites were identified from mass spectra and comparison of their changes in their accurate molecular masses and fragment ions with those of the parent drug. With the high resolution and good mass accuracy achieved by this technique, the elemental compositions of the metabolites and their fragment ions were exactly determined. The results indicate that the N --> O group reduction is the main metabolic pathway of olaquindox metabolism in rat liver microsomes, because abundant 1-desolaquindox (M2), 4-desolaquindox (M1) and bisdesoxyolaquindox (M9) were produced during the incubation step. Seven other minor metabolites were revealed which were considered to be hydroxylation metabolites, based on the position of the quinoxaline ring or 3-methyl group and a carboxylic acid derivative on the side chain at position 2 of the quinoxaline ring. Among the identified metabolites, five new hydroxylated metabolites (M3-M7) were found for the first time in rat liver microsomes. This work will conduce to complete clarification of olaquindox metabolism, and improve the in vivo metabolism of olaquindox in food animals.

  16. Development of An Ion-Drift Time-of-Flight Chemical Ionization Mass Spectrometry Technique for Measurements of Aerosol Precursor Gases

    Science.gov (United States)

    Zheng, J.; Ma, Y.; Chen, M.

    2012-12-01

    We have developed a new technique, i.e., ion-drift time-of-flight chemical ionization mass spectrometry (ID-ToF-CIMS) for measurements of aerosol precursor gases, including ammonia, amines, organic acids and oxygenated VOCs at pptv level with a response time less than 1 s. The ID-ToF-CIMS was modified from an Aerodyne high resolution ToF-CIMS with a custom-designed ion-drift tube, which can control the ion flight velocity and hence the ion-molecular reaction time. In addition, the tunable electric field generated by the drift tube can break up water clusters to select the major reagent ions. The advantages of the ID-ToF-CIMS over the traditional quadrupole-based ID-CIMS were the high mass-resolving power of the ToF mass analyzer and the capability of simultaneous measurement of the full mass range (typically up to 300 m/z) of product ions. Using hydronium ion based reagent ions, we demonstrated that the ID-ToF-CIMS can unambiguously measure ammonia (NH3) at 18.03 m/z, methyl amine (CH3NH2) at 32.05 m/z, formic acid (HCOOH) at 47.01 m/z and acetone (CH3COCH3) at 59.05 m/z. Calibrations were performed with both compressed commercial standard gases and permeation tubes and the results showed that the instrument detection limit can reach pptv level for 1 s average time or less. The ID-ToF-CIMS was also field tested in a mobile laboratory on the campus of Nanjing University of Information Science & Technology (NUIST). The preliminary results will be discussed.

  17. [Separation and identification of beta-casein from Chinese human milk by ion exchange chromatography-matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry].

    Science.gov (United States)

    Huang, Yu; Ren, Haowei; Liu, Biao; Liu, Ning; Li, Meng; Wang, Dongmao

    2013-05-01

    The selective precipitation of whole casein from skimmed milk was achieved by the addition of calcium salt under acidic pH. The effects of pH, centrifugal force and final concentration of CaCl2 on the separation of casein were studied by measuring the purity of final products using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that casein with the highest purity could be obtained with the pH of 4.3, the centrifugal force of 10 400 g and the final concentration of CaCl2 of 60 mmol/L. The casein was processed with DEAE anion exchange chromatography and three peaks were obtained. Then the third peak (peak III) was identified with Western-Blot method and matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). The identification of Western-Blot showed that peak III can combine with the specificity of human milk beta-casein antibody, and it is proved to be human milk beta-casein. The fingerprints of peak III were nalyzed by Mascot searching, and the sequence coverage was 50%, further supporting it is human milk beta-casein. In conclusion, an effective method to obtain human milk beta-casein from milk samples through DEAE anion exchange chromatography was established, and it is suitable for the proteomics research requirements of the beta-casein from human milk.

  18. Zoom-TOFMS: addition of a constant-momentum-acceleration "zoom" mode to time-of-flight mass spectrometry.

    Science.gov (United States)

    Dennis, Elise A; Gundlach-Graham, Alexander W; Ray, Steven J; Enke, Christie G; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2014-11-01

    In this study, we demonstrate the performance of a new mass spectrometry concept called zoom time-of-flight mass spectrometry (zoom-TOFMS). In our zoom-TOFMS instrument, we combine two complementary types of TOFMS: conventional, constant-energy acceleration (CEA) TOFMS and constant-momentum acceleration (CMA) TOFMS to provide complete mass-spectral coverage as well as enhanced resolution and duty factor for a narrow, targeted mass region, respectively. Alternation between CEA- and CMA-TOFMS requires only that electrostatic instrument settings (i.e., reflectron and ion optics) and ion acceleration conditions be changed. The prototype zoom-TOFMS instrument has orthogonal-acceleration geometry, a total field-free distance of 43 cm, and a direct-current glow-discharge ionization source. Experimental results demonstrate that the CMA-TOFMS "zoom" mode offers resolution enhancement of 1.6 times over single-stage acceleration CEA-TOFMS. For the atomic mass range studied here, the maximum resolving power at full-width half-maximum observed for CEA-TOFMS was 1,610 and for CMA-TOFMS the maximum was 2,550. No difference in signal-to-noise (S/N) ratio was observed between the operating modes of zoom-TOFMS when both were operated at equivalent repetition rates. For a 10-kHz repetition rate, S/N values for CEA-TOFMS varied from 45 to 990 and from 67 to 10,000 for CMA-TOFMS. This resolution improvement is the result of a linear TOF-to-mass scale and the energy-focusing capability of CMA-TOFMS. Use of CMA also allows ions outside a given m/z range to be rejected by simple ion-energy barriers to provide a substantial improvement in duty factor.

  19. Characterizing and classifying water-based lubricants using direct analysis in real time(®)-time of flight mass spectrometry.

    Science.gov (United States)

    Maric, Mark; Bridge, Candice

    2016-09-01

    Lubricant analysis is a relatively recent addition to the examination protocol in sexual assault cases by the forensic science community. Currently, lubricants cannot be unequivocally identified, although their presence can be determined based on the detection of a few chemical components, i.e. polydimethylsiloxane, polyethylene glycol, glycerol or nonoxynol-9. Confirmation of their presence typically requires that an authentic reference sample be submitted and compared to the unknown sample to determine if they potentially came from the same source. In this study, 33 individual personal water-based lubricants were characterized by direct analysis in real time-time of flight mass spectroscopy (DART-TOFMS). The resultant mass spectral data were evaluated using well-established multivariate statistical techniques, such as principal component and linear discriminant analysis. Statistical analysis revealed six different groupings within the data that could be correlated to sub-categories of water-based lubricants that contain additives in the form of anesthetics, sensation enhancers and flavorings. This variability in the personal lubricant sources can be utilized to aid in identifying the specific type of lubricant when only a questioned sample is available.

  20. Qualitative and quantitative analysis of Andrographis paniculata by rapid resolution liquid chromatography/time-of-flight mass spectrometry.

    Science.gov (United States)

    Song, Yong-Xi; Liu, Shi-Ping; Jin, Zhao; Qin, Jian-Fei; Jiang, Zhi-Yuan

    2013-09-30

    A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS) method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R² > 0.9995) within the test ranges. The overall limits of detection (LODs) and limits of quantification (LOQs) were 0.02 μg/mL to 0.06 μg/mL and 0.06 μg/mL to 0.2 μg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs) less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption.

  1. Effect of surface-enhanced laser desorption/ionization time-of-flight mass spectrometry on identifing biomarkers of endometriosis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; FENG Jie; CHANG Xiao-hong; LI Zhong-xing; WU Xiao-yi; CUI Heng

    2009-01-01

    Background Endometriosis is a common gynecological disease. This study aimed to screen proteins that were expressed differently in patients with endometriosis versus normal controls using proteomic techniques, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).Methods Protein chip SELDI-TOF-MS combines the advantages of microarray and mass spectrometry, and can screen latent markers in sera of patients with endometriosis. Serum samples from patients and normal volunteers were analyzed by SELDI-TOF-MS.Results After comparing the serum protein spectra of 36 patients with 24 normal controls, 24 differently expressed potential biomarkers (P <0.01) were identified. Using Biomarker Pattern software, we established a tree model of the 60 serum protein spectra. When using the three biomarkers to classify the samples, the sensitivity for diagnosing endometriosis was 91.7%, specificity was 95.8%, and coincidence rate was 93.3%. Then we used serum samples from 12 patients and 8 normal controls to validate the tree model and report the sensitivity for diagnosing endometriosis was 91.7%, specificity was 75%, and coincidence rate was 85%.Conclusions SELDI-TOF-MS may be a useful tool in high-risk population screening for endometriosis. The identification and application of the biomarkers need to further study.

  2. Qualitative and Quantitative Analysis of Andrographis paniculata by Rapid Resolution Liquid Chromatography/Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jian-Fei Qin

    2013-09-01

    Full Text Available A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R2 > 0.9995 within the test ranges. The overall limits of detection (LODs and limits of quantification (LOQs were 0.02 μg/mL to 0.06 μg/mL and 0.06 μg/mL to 0.2 μg/mL, respectively. The relative standard deviations (RSDs for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption.

  3. Chemical discrimination of lubricant marketing types using direct analysis in real time time-of-flight mass spectrometry.

    Science.gov (United States)

    Maric, Mark; Harvey, Lauren; Tomcsak, Maren; Solano, Angelique; Bridge, Candice

    2017-06-30

    In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time time of flight mass spectrometry (DART-TOFMS). The instrumental data was analyzed by multivariate statistics including hierarchal cluster analysis, principal component analysis, and linear discriminant analysis. By interpreting the mass spectral data with multivariate statistics, 12 discrete groupings were identified, indicating inherent chemical diversity not only between but within the three main marketing groups. A number of unique chemical markers, both major and minor, were identified, other than the three main chemical components (i.e. PEG, PDMS and nonoxynol-9) currently used for lubricant classification. The data was validated by a stratified 20% withheld cross-validation which demonstrated that there was minimal overlap between the groupings. Based on the groupings identified and unique features of each group, a highly discriminating statistical model was then developed that aims to provide the foundation for the development of a forensic lubricant database that may eventually be applied to casework. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  4. New potential biomarkers for mesterolone misuse in human urine by liquid chromatography quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lu, Jianghai; Fernández-Álvarez, María; Yang, Sheng; He, Genye; Xu, Youxuan; Aguilera, Rodigo

    2015-01-01

    In this paper, mesterolone metabolic profiles were investigated carefully. Mesterolone was administered to one healthy male volunteer. Urinary extracts were analyzed by liquid chromatography quadruple time-of-flight mass spectrometry (LC-QTOFMS) for the first time. Liquid-liquid extraction was applied to processing urine samples, and dilute-shoot analyses of intact metabolites were also presented. In LC-QTOFMS analysis, chromatographic peaks for potential metabolites were hunt down by using the theoretical [M-H](-) as target ions in full scan experiment, and their actual deprotonated ions were analyzed in targeted MS/MS mode. Ten metabolites including seven new sulfate and three glucuronide conjugates were found for mesterolone. Because of no useful fragment ion for structural elucidation, gas chromatography-mass spectrometry instrumentation was employed to obtain structural details of the trimethylsilylated phase I metabolite released after solvolysis. Thus, their potential structures were proposed particularly by a combined MS approach. All the metabolites were also evaluated in terms of how long they could be detected, and S1 (1α-methyl-5α-androst-3-one-17β-sulfate) together with S2 (1α-methyl-5α-androst-17-one-3β-sulfate) was detected up to 9 days after oral administration, which could be the new potential biomarkers for mesterolone misuse.

  5. Monitoring the in vivo and in vitro metabolism of immunomodulators by time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Muddiman, D.C.; Gusev, A.I.; Proctor, A. [Univ. of Pittsburgh, PA (United States)] [and others

    1995-12-31

    Time-of-Flight Secondary-Ion (TOF-SIMS) and Matrix-Assisted Laser Desorption/Ionization (MALDI) Mass Spectrometry are emerging as useful methods for the investigation of drugs and metabolites in real biological systems. Mass spectrometry is a powerful tool for the analysis of drugs and metabolites that may prove to be a viable alternative to high performance liquid chromatography (HPLC) and immunoassays (e.g. Fluorescence Polarization Immunoassay (FPIA)) in the clinical laboratory. Cyclosporin A (CsA) is a well characterized and extensively used anti-rejection drug with newer agents, such as FK-506, undergoing clinical trials. The therapeutic index of these agents can be improved by understanding the nature of their metabolism and pharmacokinetics. This report expands upon the initial CsA study by monitoring the in vivo metabolism of the drug and quantifying the major metabolite, AMI (M17) in whole blood extracts. Initial MALDI results of the in vitro metabolism of FK-506 using a hepatic microsomal system are also presented. FK-506 metabolism was investigated using Baboon microsomes because FK-506 will be used in xenotransplantation; thus it is important to understand how the drug is metabolized by other species that may serve as donors.

  6. Preanalytical and analytical variation of surface-enhanced laser desorption-ionization time-of-flight mass spectrometry of human serum

    DEFF Research Database (Denmark)

    Albrethsen, Jakob; Bøgebo, Rikke; Olsen, Jesper

    2006-01-01

    BACKGROUND: Surface-enhanced laser desorption-ionization time-of-flight (SELDI-TOF) mass spectrometry of human serum is a potential diagnostic tool in human diseases. In the present study, the preanalytical and analytical variation of SELDI-TOF mass spectrometry of serum was assessed in healthy...

  7. Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization

    DEFF Research Database (Denmark)

    Norgaard, Asger W.; Kofoed-Sorensen, Vivi; Svensmark, Bo

    2013-01-01

    A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection...

  8. A SIMPLE AND RAPID MATRIX-ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTROMETRY METHOD TO SCREEN FISH PLASMA SAMPLES FOR ESTROGEN-RESPONSIVE BIOMARKERS

    Science.gov (United States)

    In this study, we describe and evaluate the performance of a simple and rapid mass spectral method for screening fish plasma for estrogen-responsive biomarkers using matrix assisted laster desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) couopled with a short...

  9. Coupling passive sampling and time of flight mass spectrometry for a better estimation of polar pesticide freshwater contamination: Simultaneous target quantification and screening analysis.

    Science.gov (United States)

    Guibal, Robin; Lissalde, Sophie; Charriau, Adeline; Poulier, Gaëlle; Mazzella, Nicolas; Guibaud, Gilles

    2015-03-27

    The aim of this study was first to develop and validate an analytical method for the quantification of 35 polar pesticides and 9 metabolites by ultra-high-performance-liquid chromatography combined with a high resolution time-of-flight mass spectrometer detector (UHPLC-(Q)-TOF). Various analytical conditions were investigated (eluent composition and mass parameters) to optimize analyte responses. Analytical performance (linearity, limit of quantification, and accuracy) was then evaluated and interference in the extract of a passive sampler exposed in freshwater (POCIS: Polar Organic Chemical Integrative Sampler) was studied. The proposed quantification method was validated for 43 compounds with variation of calibration slopes below 10% in environmental matrix. For the unvalidated compound DIA (atrazine-desisopropyl: an atrazine metabolite), interference increased the error of concentration determination (50%). The limits of quantification obtained by combining POCIS and UHPLC-(Q)-TOF for 43 target compounds were between 0.1 (terbuthylazine) and 10.7 ng/L (acetochlor). Secondly, the method was successfully applied during a 14-day POCIS river exposure, and gave concentration values similar to a more commonly used triple quadrupole detector regarding concentration, but allowed for the detection of more compounds. Additionally with the targeted compound quantification, the (Q)-TOF mass spectrometer was also used for screening non-target compounds (other pesticides and pharmaceuticals) in POCIS extracts. Moreover, the acquisition of full scan MS data allowed the identification of the polyethylene glycol (PEG) compounds which gave unresolvable interference to DIA, and thus questions the ability of DIA to be used as performance reference compound (PRC) to determine sampling rates in situ. This study therefore illustrates the potential, and proposes a pathway, of UHPLC-(Q)-TOF combined with POCIS in situ pre-concentration for both quantitative and screening analyses of

  10. Insights on Clusters Formation Mechanism by Time of Flight Mass Spectrometry. 2. The Case of Acetone-Water Clusters

    Science.gov (United States)

    Apicella, B.; Li, X.; Passaro, M.; Russo, C.

    2016-11-01

    This paper is the second of a series dealing with clusters formation mechanism. In part 1, water clusters with the addition of an electrophilic molecule such as ethanol were studied by Time Of Flight Mass Spectrometry (TOFMS). Mass distributions of molecular clusters of ethanol, water and ethanol-water mixed clusters, were obtained by means of two different ionization methods: Electron Ionization (EI) and picosecond laser Photo-Ionization (PI) at a wavelength of 355 nm. In part 2, the same experimental approach was employed to obtain mass spectra of clusters generated by acetone-water binary mixtures with a different composition. Strong dependence of the mass spectra of clusters with EI and PI on the acetone-water mixing ratio was observed. It was shown that the spectral pattern changes gradually and water-rich cluster signals become fainter while acetone-rich cluster signals become more intensive with increasing acetone concentrations from 0.3% to 40%. Owing to the hydrogen bond acceptor character of acetone, its self-association is discouraged with respect to ethanol. The autocorrelation function (AF) was used to analyze the variation of the water clusters composition with the increase of the acetone concentration in terms of fundamental periodicities. However, although acetone and ethanol present a very different hydrogen-bonding ability, similarly to ethanol-water system, in acetone-water system the formation of water-rich clusters and subsequent metastable fragmentation are the dominant process that determine the clusters distribution, irrespective of the ionization process, while the ionization process significantly affects the acetone-rich clusters distribution.

  11. Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    González, Susana; Petrović, Mira; Radetic, Maja; Jovancic, Petar; Ilic, Vesna; Barceló, Damià

    2008-05-01

    A method based on the application of ultra-performance liquid chromatography (UPLC) coupled to hybrid quadrupole-time-of-flight mass spectrometry (QqTOF-MS) with an electrospray (ESI) interface has been developed for the screening and confirmation of several anionic and non-ionic surfactants: linear alkylbenzenesulfonates (LAS), alkylsulfate (AS), alkylethersulfate (AES), dihexyl sulfosuccinate (DHSS), alcohol ethoxylates (AEOs), coconut diethanolamide (CDEA), nonylphenol ethoxylates (NPEOs), and their degradation products (nonylphenol carboxylate (NPEC), octylphenol carboxylate (OPEC), 4-nonylphenol (NP), 4-octylphenol (OP) and NPEO sulfate (NPEO-SO4). The developed methodology permits reliable quantification combined with a high accuracy confirmation based on the accurate mass of the (de)protonated molecules in the TOFMS mode. For further confirmation of the identity of the detected compounds the QqTOF mode was used. Accurate masses of product ions obtained by performing collision-induced dissociation (CID) of the (de)protonated molecules of parent compounds were matched with the ions obtained for a standard solution. The method was applied for the quantitative analysis and high accuracy confirmation of surfactants in complex mixtures in effluents from the textile industry. Positive identification of the target compounds was based on accurate mass measurement of the base peak, at least one product ion and the LC retention time of the analyte compared with that of a standard. The most frequently surfactants found in these textile effluents were NPEO and NPEO-SO4 in concentrations ranging from 0.93 to 5.68 mg/L for NPEO and 0.06 to 4.30 mg/L for NPEO-SO4. AEOs were also identified.

  12. Thermally Accelerated Oxidative Degradation of Quercetin Using Continuous Flow Kinetic Electrospray-Ion Trap-Time of Flight Mass Spectrometry

    Science.gov (United States)

    Barnes, Jeremy S.; Foss, Frank W.; Schug, Kevin A.

    2013-10-01

    Thermally accelerated oxidative degradation of aqueous quercetin at pH 5.9 and 7.4 was kinetically measured using an in-house built online continuous flow device made of concentric capillary tubes, modified to fit to the inlet of an electrospray ionization-ion trap-time-of-flight-mass spectrometer (ESI-IT-TOF-MS). Time-resolved mass spectral measurements ranging from 2 to 21 min were performed in the negative mode to track intermediate degradation products and to evaluate the degradation rate of the deprotonated quercetin ion, [Q-H]-. Upon heating solutions in the presence of dissolved oxygen, degradation of [Q-H]- was observed and was accelerated by an increase in pH and temperature. Regardless of the condition, the same degradation pathways were observed. Degradation mechanisms and structures were determined using higher order tandem mass spectrometry (up to MS3) and high mass accuracy. The observed degradation mechanisms included oxidation, hydroxylation, and ring-cleavage by nucleophilic attack. A chalcan-trione structure formed by C-ring opening after hydroxylation at C2 was believed to be a precursor for other degradation products, formed by hydroxylation at the C2, C3, and C4 carbons from attack by nucleophilic species. This resulted in A-type and B-type ions after cross-ring cleavage of the C-ring. Based on time of appearance and signal intensity, nucleophilic attack at C3 was the preferred degradation pathway, which generated 2,4,6-trihydroxymandelate and 2,4,6-trihydroxyphenylglyoxylate ions. Overall, 23 quercetin-related ions were observed.

  13. Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Aircraft Turbine Engines.

    Science.gov (United States)

    Kilic, Dogushan; Brem, Benjamin T; Klein, Felix; El-Haddad, Imad; Durdina, Lukas; Rindlisbacher, Theo; Setyan, Ari; Huang, Rujin; Wang, Jing; Slowik, Jay G; Baltensperger, Urs; Prevot, Andre S H

    2017-03-17

    Nonmethane organic gas emissions (NMOGs) from in-service aircraft turbine engines were investigated using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) at an engine test facility at Zurich Airport, Switzerland. Experiments consisted of 60 exhaust samples for seven engine types (used in commercial aviation) from two manufacturers at thrust levels ranging from idle to takeoff. Emission indices (EIs) for more than 200 NMOGs were quantified, and the functional group fractions (including acids, carbonyls, aromatics, and aliphatics) were calculated to characterize the exhaust chemical composition at different engine operation modes. Total NMOG emissions were highest at idling with an average EI of 7.8 g/kg fuel and were a factor of ∼40 lower at takeoff thrust. The relative contribution of pure hydrocarbons (particularly aromatics and aliphatics) of the engine exhaust decreased with increasing thrust while the fraction of oxidized compounds, for example, acids and carbonyls increased. Exhaust chemical composition at idle was also affected by engine technology. Older engines emitted a higher fraction of nonoxidized NMOGs compared to newer ones. Idling conditions dominated ground level organic gas emissions. Based on the EI determined here, we estimate that reducing idle emissions could substantially improve air quality near airports.

  14. Direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry improves appropriateness of antibiotic treatment of bacteremia.

    Science.gov (United States)

    Vlek, Anne L M; Bonten, Marc J M; Boel, C H Edwin

    2012-01-01

    Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows the identification of microorganisms directly from positive blood culture broths. Use of the MALDI-TOF MS for rapid identification of microorganisms from blood culture broths can reduce the turnaround time to identification and may lead to earlier appropriate treatment of bacteremia. During February and April 2010, direct MALDI-TOF MS was routinely performed on all positive blood cultures. During December 2009 and March 2010 no direct MALDI-TOF MS was used. Information on antibiotic therapy was collected from the hospital and intensive care units' information systems from all positive blood cultures during the study period. In total, 253 episodes of bacteremia were included of which 89 during the intervention period and 164 during the control period. Direct performance of MALDI-TOF MS on positive blood culture broths reduced the time till species identification by 28.8-h and was associated with an 11.3% increase in the proportion of patients receiving appropriate antibiotic treatment 24 hours after blood culture positivity (64.0% in the control period versus 75.3% in the intervention period (p0.01)). Routine implementation of this technique increased the proportion of patients on adequate antimicrobial treatment within 24 hours.

  15. Direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry improves appropriateness of antibiotic treatment of bacteremia.

    Directory of Open Access Journals (Sweden)

    Anne L M Vlek

    Full Text Available Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS allows the identification of microorganisms directly from positive blood culture broths. Use of the MALDI-TOF MS for rapid identification of microorganisms from blood culture broths can reduce the turnaround time to identification and may lead to earlier appropriate treatment of bacteremia. During February and April 2010, direct MALDI-TOF MS was routinely performed on all positive blood cultures. During December 2009 and March 2010 no direct MALDI-TOF MS was used. Information on antibiotic therapy was collected from the hospital and intensive care units' information systems from all positive blood cultures during the study period. In total, 253 episodes of bacteremia were included of which 89 during the intervention period and 164 during the control period. Direct performance of MALDI-TOF MS on positive blood culture broths reduced the time till species identification by 28.8-h and was associated with an 11.3% increase in the proportion of patients receiving appropriate antibiotic treatment 24 hours after blood culture positivity (64.0% in the control period versus 75.3% in the intervention period (p0.01. Routine implementation of this technique increased the proportion of patients on adequate antimicrobial treatment within 24 hours.

  16. Rapid Microcystin Determination Using a Paper Spray Ionization Method with a Time-of-Flight Mass Spectrometry System.

    Science.gov (United States)

    Zhu, Xiaoqiang; Huang, Zhengxu; Gao, Wei; Li, Xue; Li, Lei; Zhu, Hui; Mo, Ting; Huang, Bao; Zhou, Zhen

    2016-07-13

    The eutrophication of surface water sources and climate changes have resulted in an annual explosion of cyanobacterial blooms in many irrigating and drinking water resources. To decrease health risks to the public, a rapid real time method for the synchronous determination of two usually harmful microcystins (MC-RR and MC-LR) in environmental water samples was built by employing a paper spray ionization method coupled with a time-of-flight mass spectrometer system. With this approach, direct analysis of microcystin mixtures without sample preparation has been achieved. Rapid detection was performed, simulating the release process of microcystins in reservoir water samples, and the routine detection frequency was every three minutes. The identification time of microcystins was reduced from several hours to a few minutes. The limit of detection is 1 μg/L, and the limit of quantitation is 3 μg/L. This method displays the ability for carrying out rapid, direct, and high-throughput experiments for determination of microcystins, and it would be of significant interest for environmental and food safety applications.

  17. Profiling the Metabolism of Astragaloside IV by Ultra Performance Liquid Chromatography Coupled with Quadrupole/Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xu-Dong Cheng

    2014-11-01

    Full Text Available Astragaloside IV is a compound isolated from the Traditional Chinese Medicine Astragalus membranaceus, that has been reported to have bioactivities against cardiovascular disease and kidney disease. There is limited information on the metabolism of astragaloside IV, which impedes comprehension of its biological actions and pharmacology. In the present study, an ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS-based approach was developed to profile the metabolites of astragaloside IV in rat plasma, bile, urine and feces samples. Twenty-two major metabolites were detected. The major components found in plasma, bile, urine and feces included the parent chemical and phases I and II metabolites. The major metabolic reactions of astragaloside IV were hydrolysis, glucuronidation, sulfation and dehydrogenation. These results will help to improve understanding the metabolism and reveal the biotransformation profiling of astragaloside IV in vivo. The metabolic information obtained from our study will guide studies into the pharmacological activity and clinical safety of astragaloside IV.

  18. Microextraction by packed sorbent liquid chromatography with time-of-flight mass spectrometry of triazines employing a molecularly imprinted polymer.

    Science.gov (United States)

    Andrade, Felipe Nascimento; Santos-Neto, Álvaro José; Lanças, Fernando Mauro

    2014-11-01

    Molecularly imprinted polymers for the determination of triazines were synthesized by precipitation using atrazine as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, and 2,2'-azobisisobutrynitrile as initiator. The polymers were characterized by infrared spectroscopy and scanning electron microscopy and packed in a device for microextraction by packed sorbent aiming for the preconcentration/cleanup of herbicides, such as atrazine, simazine, simetryn, ametryn, and terbutryn in corn samples. Liquid chromatography coupled with time-of-flight mass spectrometry was used for the separation and determination of the herbicides. The selectivity coefficient of molecularly imprinted polymers was compared with that of nonimprinted polymer for the binary mixtures of atrazine/propanil and atrazine/picloram, and the values obtained were 15.6 and 2.96, respectively. The analytical curve ranged from 10 to 80 μg/kg (r = 0.989) and the limits of detection and quantification in the corn matrices were 3.3 and 10 μg/kg, respectively. Intra- and interday precisions were Polymer synthesis was successfully applied to the cleanup and preconcentration of triazines from fortified corn samples with 91.1-109.1% of recovery.

  19. Dispersive liquid-liquid microextraction combined with capillary electrophoresis and time-of-flight mass spectrometry for urine analysis.

    Science.gov (United States)

    Kohler, Isabelle; Schappler, Julie; Sierro, Tatiana; Rudaz, Serge

    2013-01-25

    The combination of dispersive liquid-liquid microextraction (DLLME) with capillary electrophoresis (CE) and a time-of-flight mass spectrometer (TOF-MS) was evaluated for the toxicological screening in urine samples. A methodology based on design of experiments (DOE) was implemented to increase the extraction efficiency. Dichloromethane and isopropanol were selected as the extraction and dispersing solvents, respectively. Seven factors for DLLME were screened with the help of a Plackett-Burmann DOE using two model compounds before fine investigation of the important parameters to maximise the compound extraction. These experiments were performed in the CE-UV configuration to overcome potential MS matrix effects. The performance of the entire procedure was then evaluated using CE-ESI-TOF-MS. With a preconcentration factor of more than 130, the highly sensitive DLLME-CE-ESI-TOF-MS method allowed for the detection of 30 toxicological compounds (i.e., amphetamines and their derivatives, opiates, cocaine and its metabolites and pharmaceuticals) in urine with limits of detection in the sub-ng/mL level and was used to analyse real toxicological samples. The combination of DLLME and CE was particularly attractive because of the small amount of organic solvents required.

  20. Characterization of the Clostridium difficile volatile metabolome using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

    Science.gov (United States)

    Rees, Christiaan A; Shen, Aimee; Hill, Jane E

    2016-12-15

    Clostridium difficile is a bacterial pathogen capable of causing life-threatening infections of the gastrointestinal tract characterized by severe diarrhea. Exposure to certain classes of antibiotics, advanced age, and prolonged hospitalizations are known risk factors for infection by this organism. Anecdotally, healthcare providers have reported that they can smell C. difficile infections in their patients, and several studies have suggested that there may indeed be an olfactory signal associated with C. difficile-associated diarrhea. In this study, we sought to characterize the volatile molecules produced by an epidemic strain of C. difficile (R20291) using headspace solid-phase microextraction (HS-SPME) followed by two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS). We report on a set of 77 volatile compounds, of which 59 have not previously been associated with C. difficile growth in vitro. Amongst these reported compounds, we detect both straight-chain and branched-chain carboxylic acids, as well as p-cresol, which have been the primary foci of C. difficile volatile metabolomic studies to-date. We additionally report on novel sulfur-containing and carbonyl-containing molecules that have not previously been reported for C. difficile. With the identification of these novel C. difficile-associated volatile compounds, we demonstrate the superior resolution and sensitivity of GC×GC-TOFMS relative to traditional GC-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Systemic Metabolomic Changes in Blood Samples of Lung Cancer Patients Identified by Gas Chromatography Time-of-Flight Mass Spectrometry

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    Suzanne Miyamoto

    2015-04-01

    Full Text Available Lung cancer is a leading cause of cancer deaths worldwide. Metabolic alterations in tumor cells coupled with systemic indicators of the host response to tumor development have the potential to yield blood profiles with clinical utility for diagnosis and monitoring of treatment. We report results from two separate studies using gas chromatography time-of-flight mass spectrometry (GC-TOF MS to profile metabolites in human blood samples that significantly differ from non-small cell lung cancer (NSCLC adenocarcinoma and other lung cancer cases. Metabolomic analysis of blood samples from the two studies yielded a total of 437 metabolites, of which 148 were identified as known compounds and 289 identified as unknown compounds. Differential analysis identified 15 known metabolites in one study and 18 in a second study that were statistically different (p-values <0.05. Levels of maltose, palmitic acid, glycerol, ethanolamine, glutamic acid, and lactic acid were increased in cancer samples while amino acids tryptophan, lysine and histidine decreased. Many of the metabolites were found to be significantly different in both studies, suggesting that metabolomics appears to be robust enough to find systemic changes from lung cancer, thus showing the potential of this type of analysis for lung cancer detection.

  2. Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry for the identification of Neisseria gonorrhoeae.

    Science.gov (United States)

    Buchanan, R; Ball, D; Dolphin, H; Dave, J

    2016-09-01

    Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) was compared with the API NH biochemical method for the identification of Neisseria gonorrhoeae in routine clinical samples. A retrospective review of laboratory records for 1090 isolates for which both biochemical and MALDI-TOF MS identifications were available was performed. Cases of discrepant results were examined in detail for evidence supportive of a particular organism identification. Of 1090 isolates, 1082 were identified as N. gonorrhoeae by API NH. MALDI-TOF MS successfully identified 984 (91%) of these after one analysis, rising to 1081 (99.9%) after two analyses, with a positive predictive value of 99.3%. For those isolates requiring a repeat analysis, failure to generate an identifiable proteomic signature was the reason in 76% of cases, with alternative initial identifications accounting for the remaining 24%. MALDI-TOF MS identified eight isolates as N. gonorrhoeae that were not identified as such by API NH-examination of these discrepant results suggested that the MALDI-TOF MS identification may be the more reliable. MALDI-TOF MS is at least as accurate and reliable a method of identifying N. gonorrhoeae as API NH. We propose that MALDI-TOF MS could potentially be used as a single method for N. gonorrhoeae identification in routine cases by laboratories with access to this technology.

  3. Analysis of the oligosaccharides in Japanese rice wine, sake, by hydrophilic interaction liquid chromatography-time-of-flight/mass spectrometry.

    Science.gov (United States)

    Tokuoka, Masafumi; Honda, Chihiro; Totsuka, Akira; Shindo, Hitoshi; Hosaka, Masaru

    2017-08-01

    A traditional Japanese alcoholic beverage, sake, contains several oligosaccharides, which are associated with the taste of sake; however, little is known about the specific molecular species and concentrations of oligosaccharides in sake. Here, we developed an analytical method using hydrophilic interaction liquid chromatography-time-of-flight/mass spectrometry (HILIC-TOF/MS) which successfully detects the oligosaccharides in sake. A series of oligosaccharides with successive degree of polymerization (DP) values up to 18 were identified in sake for the first time, which we have named sake oligosaccharides (SAOs). The concentrations of the SAOs with DP = 3-8 were estimated to be in the range of 200-2000 ppm. Quantitative analysis of 6 different sake samples for SAOs with DP=2-8 and the other saccharides showed that the amount of each SAO differs significantly among the sake samples. Enzymatic digestion analysis suggested that the SAOs are probably branched maltooligosaccharides in structure, which are resistant to β-amylase. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Cooking Emissions.

    Science.gov (United States)

    Klein, Felix; Platt, Stephen M; Farren, Naomi J; Detournay, Anais; Bruns, Emily A; Bozzetti, Carlo; Daellenbach, Kaspar R; Kilic, Dogushan; Kumar, Nivedita K; Pieber, Simone M; Slowik, Jay G; Temime-Roussel, Brice; Marchand, Nicolas; Hamilton, Jacqueline F; Baltensperger, Urs; Prévôt, André S H; El Haddad, Imad

    2016-02-02

    Cooking processes produce gaseous and particle emissions that are potentially deleterious to human health. Using a highly controlled experimental setup involving a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), we investigate the emission factors and the detailed chemical composition of gas phase emissions from a broad variety of cooking styles and techniques. A total of 95 experiments were conducted to characterize nonmethane organic gas (NMOG) emissions from boiling, charbroiling, shallow frying, and deep frying of various vegetables and meats, as well as emissions from vegetable oils heated to different temperatures. Emissions from boiling vegetables are dominated by methanol. Significant amounts of dimethyl sulfide are emitted from cruciferous vegetables. Emissions from shallow frying, deep frying and charbroiling are dominated by aldehydes of differing relative composition depending on the oil used. We show that the emission factors of some aldehydes are particularly large which may result in considerable negative impacts on human health in indoor environments. The suitability of some of the aldehydes as tracers for the identification of cooking emissions in ambient air is discussed.

  5. Corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry for monitoring of volatile organic compounds.

    Science.gov (United States)

    Sabo, Martin; Matejčík, Štefan

    2012-06-19

    We demonstrate the application of corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry (CD IMS-oaTOF) for volatile organic compounds (VOCs) monitoring. Two-dimensional (2D) IMS-oaTOF spectra of VOCs were recorded in nearly real time. The corona discharge atmospheric pressure chemical ionization (APCI) source was operated in positive mode in nitrogen and air. The CD ion source generates in air H(3)O(+)(H(2)O)(n) and NO(+). The NO(+) offers additional possibility for selective ionization and for an increase of the sensitivity of monoaromatic compounds. In addition to H(3)O(+)(H(2)O)(n) and NO(+), we have carried out ionization of VOCs using acetone as dopant gas ((CH(3))(2)COH(+)). Sixteen model VOCs (tetrahydrofuran, butanol, n-propanol, iso-propano, acetone, methanol, ethanol, toluene, benzene, amomnia, dioxan, triethylamine, acetonitrile, formaldehyde, m-xylene, 2,2,2-trifluoroethylamine) were tested using these ionization techniques.

  6. Analysis of psychoactive substances in water by information dependent acquisition on a hybrid quadrupole time-of-flight mass spectrometer.

    Science.gov (United States)

    Andrés-Costa, María Jesús; Andreu, Vicente; Picó, Yolanda

    2016-08-26

    Emerging drugs of abuse, belonging to many different chemical classes, are attracting users with promises of "legal" highs and easy access via internet. Prevalence of their consumption and abuse through wastewater-based epidemiology can only be realized if a suitable analytical screening procedure exists to detect and quantify them in water. Solid-phase extraction and ultra-high performance liquid chromatography quadrupole time-of-flight-mass spectrometry (UHPLC-QqTOF-MS/MS) was applied for rapid suspect screening as well as for the quantitative determination of 42 illicit drugs and metabolites in water. Using this platform, we were able to identify amphetamines, tryptamines, piperazines, pyrrolidinophenones, arylcyclohexylamines, cocainics, opioids and cannabinoids. Additionally, paracetamol, carbamazepine, ibersartan, valsartan, sulfamethoxazole, terbumeton, diuron, etc. (including degradation products as 3-hydroxy carbamazepine or deethylterbuthylazine) were detected. This method encompasses easy sample preparation and rapid identification of psychoactive drugs against a database that cover more than 2000 compounds that ionized in positive mode, and possibility to identify metabolites and degradation products as well as unknown compounds. The method for river water, influent and effluents samples was fully validated for the target psychoactive substances including assessment of matrix effects (-88-67.8%), recovery (42-115%), precision (psychoactive drugs biomarkers and other water contaminants is demonstrated.

  7. Localization of fatty acids with selective chain length by imaging time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Richter, Katrin; Nygren, Håkan; Malmberg, Per; Hagenhoff, Birgit

    2007-07-01

    Localization of fatty acids in biological tissues was made by using TOF-SIMS (time-of-flight secondary ion mass spectrometry). Two cell-types with a specific fatty acid distribution are shown. In rat cerebellum, different distribution patterns of stearic acid (C18:0), palmitic acid (C16:0), and oleic acid (C18:1) were found. Stearic acid signals were observed accumulated in Purkinje cells with high intensities inside the cell, but not in the nucleus region. The signals colocalized with high intensity signals of the phosphocholine head group, indicating origin from phosphatidylcholine or sphingomyelin. In mouse intestine, high palmitic acid signals were found in the secretory crypt cells together with high levels of phosphorylinositol colocalized in the crypt region. Palmitic acid was also seen in the intestinal lumen that contains high amounts of mucine, which is known to be produced in the crypt cells. Linoleic acid signals (C18:2) were low in the crypt region and high in the villus region. Oleic acid signals were seen in the villi and stearic acid signals were ubiquitous with no specific localization in the intestine. We conclude that the results obtained by using imaging TOF-SIMS are consistent with known brain and intestine biochemistry and that the localization of fatty acids is specific in differentiated cells.

  8. Metabolite Analysis of Toosendanin by an Ultra-High Performance Liquid Chromatography-Quadrupole-Time of Flight Mass Spectrometry Technique

    Directory of Open Access Journals (Sweden)

    Na Li

    2013-09-01

    Full Text Available Toosendanin is the major bioactive component of Melia toosendan Sieb. et Zucc., which is traditionally used for treatment of abdominal pain and as an insecticide. Previous studies reported that toosendanin possesses hepatotoxicity, but the mechanism remains unknown. Its bioavailability in rats is low, which indicates the hepatotoxicity might be induced by its metabolites. In this connection, in the current study, we examined the metabolites obtained by incubating toosendanin with human live microsomes, and then six of these metabolites (M1–M6 were identified for the first time by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF/MS. Further analysis on the MS spectra showed M1, M2, and M3 are oxidative products and M6 is a dehydrogenation product, while M4 and M5 are oxidative and dehydrogenation products of toosendanin. Moreover, their possible structures were deduced from the MS/MS spectral features. Quantitative analysis demonstrated that M1-M5 levels rapidly increased and reached a plateau at 30 min, while M6 rapidly reached a maximal level at 20 min and then decreased slowly afterwards. These findings have provided valuable data not only for understanding the metabolic fate of toosendanin in liver microsomes, but also for elucidating the possible molecular mechanism of its hepatotoxicity.

  9. Analysis of special surfactants by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

    Science.gov (United States)

    Wulf, Volker; Wienand, Nils; Wirtz, Michaela; Kling, Hans-Willi; Gäb, Siegmar; Schmitz, Oliver J

    2010-01-29

    Multidimensional gas-chromatographic analyses of olesochemically based nonionic, anionic and several cationic surfactants in industrial cleaners are demonstrated. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry allows the simultaneous determination of fatty alcohols, fatty alcohol sulphates and alkyl polyglucosides. In addition, the determination of fatty alcohol ethoxylates up to C(10)EO(8) (highest degree of ethoxylation) and C(18)EO(5) (longest C-chain at an ethoxylation degree of five) and the analysis of fatty alcohol alkoxylates that contain ethoxy (EO) and propoxy (PO) groups could be realized. Because of decomposition in the injector and a weak EI-fragmentation, cationic surfactants such as alkyl benzyl dimethyl ammonium chloride could also be identified by their characteristic fragments. Thermogravimetric analyses confirmed that the temperature in a normal GC injector is not high enough to cause thermal decomposition of esterquats. However, we could demonstrate that a modified silylation procedure forms decomposition products of esterquats in the GC injector which are detectable by GCxGC-(TOF)MS and allows the identification of such GC-atypical analytes.

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

    Science.gov (United States)

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

    2015-11-01

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

  11. [Development of a chemical ionization time-of-flight mass spectrometer for continuous measurements of atmospheric hydroxyl radical].

    Science.gov (United States)

    Dou, Jian; Hua, Lei; Hou, Ke-Yong; Jiang, Lei; Xie, Yuan-Yuan; Zhao, Wu-Duo; Chen, Ping; Wang, Wei-Guo; Di, Tian; Li, Hai-Yang

    2014-05-01

    A home-made chemical ionization time-of-flight mass spectrometer (TOFMS) has been developed for continuous measurements of atmospheric hydroxyl radical. Based on the atmospheric pressure chemical ionization technique, an ionization source with orthogonal dual tube structure was adopted in the instrument, which minimized the interference between the reagent gas ionization and the titration reaction. A 63Ni radioactive source was fixed inside one of the orthogonal tubes to generate reactant ion of NO(-)(3) from HNO3 vapor. Hydroxyl radical was first titrated by excess SO2 to form equivalent concentrations of H2SO4 in the other orthogonal tube, and then reacted with NO(-)(3) ions in the chemical ionization chamber, leading to HSO(-)(4) formation. The concentration of atmospheric hydroxyl radical can be directly calculated by measuring the intensities of the HSOj product ions and the NO(-)(3) reactant ions. The analytical capability of the instrument was demonstrated by measuring hydroxyl radical in laboratory air, and the concentration of the hydroxyl radical in the investigated air was calculated to be 1.6 x 106 molecules*cm ', based on 5 seconds integration. The results have shown that the instrument is competent for in situ continuous measurements of atmospheric trace radical.

  12. Quasi-trapping chemical ionization source based on a commercial VUV lamp for time-of-flight mass spectrometry.

    Science.gov (United States)

    Chen, Ping; Hou, Keyong; Hua, Lei; Xie, Yuanyuan; Zhao, Wuduo; Chen, Wendong; Chen, Chuang; Li, Haiyang

    2014-02-04

    The application of VUV lamp-based single photon ionization (SPI) was limited due to low photon energy and poor photon flux density. In this work, we designed a quasi-trapping chemical ionization (QT-CI) source with a commercial VUV 10.6 eV krypton lamp for time-of-flight mass spectrometry. The three electrode configuration ion source with RF voltage on the second electrode constitutes a quasi-trapping region, which has two features: accelerating the photoelectrons originated from the photoelectric effect with VUV light to trigger the chemical ionization through ion-molecule reaction and increasing the collisions between reactant ion O2(+) and analyte molecules to enhance the efficiency of chemical ionization. Compared to single SPI based on VUV krypton lamp, the QT-CI ion source not only apparently improved the sensitivity (e.g., 12-118 fold enhancement were achieved for 13 molecules, including aromatic hydrocarbon, chlorinated hydrocarbon, hydrogen sulfide, etc.) but also extended the range of ionizable molecules with ionization potential (IP) higher than 10.6 eV, such as propane, dichloroethane, and trichloromethane.

  13. Rapid identification of polymer additives by atmospheric solid analysis probe with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Du, Zhenxia; Zhang, Yun; Li, Ailin; Lv, Surong

    2014-10-15

    A method using an atmospheric solid analysis probe (ASAP) combined with quadrupole time-of-flight mass spectrometry (QTOFMS) assisted by a pre-built MS library was found to be efficient in fast and direct analysis of additives for polymers. By this method, sample pretreatment could be eliminated from the additives identification process. Some crucial parameters, such as desolvation gas temperature, corona current, sample cone voltage and collision energy, should be optimized. A MS library of 100 polymer additives, including phenols (Irganox 1010, Irganox 1076), hydroxyl phenyl benzotriazole derivatives (Tinuvin 326, Tinuvin 327, Tinuvin 328), hindered amines (Tinuvin 944, Tinuvin 770) and plasticizers, was built based on the optimized conditions. To verify the application of the MS library, the ASAP-QTOFMS method was applied to identify complex additives, a simulated polypropylene (PP) sample and a real polymethylmethacrylate (PMMA) sample purchased from a local market. By searching the exact mass, and comparing the MS and MS/MS spectra of samples with standards in the MS library, complex additives such as Irganox GX 2921, as well as additives in PP and PMMA samples, could be identified quickly and easily. The determination of mass accuracy increased the confidence of peak identification as well. Moreover, the results also provided information of the characterization for PP and PMMA polymers. A rapid identification method has been developed for polymer additives by ASAP-QTOFMS. A MS library of 100 polymer additives was built by this method. Using ASAP-QTOFMS assisted by the pre-built MS library, polymer additives can be quickly identified. This method was found to be a promising tool in the rapid analysis of additives in polymers and polymer matrices. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Screening and selective quantification of illicit drugs in wastewater by mixed-mode solid-phase extraction and quadrupole-time-of-flight liquid chromatography-mass spectrometry.

    Science.gov (United States)

    González-Mariño, Iria; Quintana, José Benito; Rodríguez, Isaac; González-Díez, Marta; Cela, Rafael

    2012-02-07

    For the first time, a mixed-mode solid-phase extraction with fractionation of basic analytes from neutral and acidic species during cartridge elution and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) was combined for the quantitative determination of 24 illicit drugs and metabolites in urban sewage samples. The effects of several sample preparation and instrumental parameters in the sensitivity and selectivity of the quantitative method are thoroughly discussed. Under final working conditions, recoveries above 63% and 82% were attained for all species in raw and treated sewage, respectively; whereas, the limits of quantification of the method, defined for a signal-to-noise of 10 (S/N = 10), ranged from 2 to 50 ng L(-1). Sequential elution of mixed-mode cartridges allowed a significant reduction of matrix effects observed during electrospray ionization of basic drugs versus those measured for hydrophilic balance reversed-phase sorbents and the same mixed-mode polymer without fractionated elution. Analysis of raw wastewater samples confirmed the ubiquity of cocaine (COC), benzoylecgonine (BE), and 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH) in this matrix. The capability of the above methodology to identify new illicit drugs and/or metabolites in sewage samples is also discussed. With this aim, a two step strategy is proposed. First, high-resolution MS chromatograms, acquired throughout each chromatographic run, are automatically searched against an in-house built database, a reduced list of candidate drugs is generated, and the corresponding extracted ion chromatograms are obtained. In a further LC run, the tandem mass spectrometry (MS/MS) spectra of unknown peaks are acquired using different collision energies and compared with those existing in public libraries, or interpreted, to assign the unknown peak to one of the previously selected candidates.

  15. Time of flight secondary ion mass spectrometry of bone-Impact of sample preparation and measurement conditions.

    Science.gov (United States)

    Henss, Anja; Hild, Anne; Rohnke, Marcus; Wenisch, Sabine; Janek, Juergen

    2015-06-07

    Time of flight secondary ion mass spectrometry (ToF-SIMS) enables the simultaneous detection of organic and inorganic ions and fragments with high mass and spatial resolution. Due to recent technical developments, ToF-SIMS has been increasingly applied in the life sciences where sample preparation plays an eminent role for the quality of the analytical results. This paper focusses on sample preparation of bone tissue and its impact on ToF-SIMS analysis. The analysis of bone is important for the understanding of bone diseases and the development of replacement materials and new drugs for the cure of diseased bone. The main purpose of this paper is to find out which preparation process is best suited for ToF-SIMS analysis of bone tissue in order to obtain reliable and reproducible analytical results. The influence of the embedding process on the different components of bone is evaluated using principal component analysis. It is shown that epoxy resin as well as methacrylate based plastics (Epon and Technovit) as embedding materials do not infiltrate the mineralized tissue and that cut sections are better suited for the ToF-SIMS analysis than ground sections. In case of ground samples, a resin layer is smeared over the sample surface due to the polishing step and overlap of peaks is found. Beside some signals of fatty acids in the negative ion mode, the analysis of native, not embedded samples does not provide any advantage. The influence of bismuth bombardment and O2 flooding on the signal intensity of organic and inorganic fragments due to the variation of the ionization probability is additionally discussed. As C60 sputtering has to be applied to remove the smeared resin layer, its effect especially on the organic fragments of the bone is analyzed and described herein.

  16. Uptake of Ra during the recrystallization of barite: a microscopic and time of flight-secondary ion mass spectrometry study.

    Science.gov (United States)

    Klinkenberg, Martina; Brandt, Felix; Breuer, Uwe; Bosbach, Dirk

    2014-06-17

    A combined macroscopic and microanalytical approach was applied on two distinct barite samples from Ra uptake batch experiments using time of flight-secondary ion mass spectrometry (ToF-SIMS) and detailed scanning electron microscopy (SEM) investigations. The experiments were set up at near to equilibrium conditions to distinguish between two possible scenarios for the uptake of Ra by already existent barite: (1) formation of a Ba1-xRaxSO4 solid solution surface layer on the barite or (2) a complete recrystallization, leading to homogeneous Ba1-xRaxSO4 crystals. It could be clearly shown that Ra uptake in all barite particles analyzed within this study is not limited to the surface but extends to the entire solid. For most grains a homogeneous distribution of Ra could be determined, indicating a complete recrystallization of barite into a Ba1-xRaxSO4 solid solution. The maxima of the Ra/Ba intensity ratio distribution histograms calculated from ToF-SIMS are identical with the expected Ra/Ba ratios calculated from mass balance assuming a complete recrystallization. In addition, the role of Ra during the recrystallization of barite was examined via detailed SEM investigations. Depending on the type of barite used, an additional coarsening effect or a strong formation of oriented aggregates was observed compared to blank samples without Ra. In conclusion, the addition of Ra to a barite at close to equilibrium conditions has a major impact on the system leading to a fast re-equilibration of the solid to a Ba1-xRaxSO4 solid solution and visible effects on the particle size distribution, even at room temperature.

  17. Identification of beer-spoilage bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Wieme, Anneleen D; Spitaels, Freek; Aerts, Maarten; De Bruyne, Katrien; Van Landschoot, Anita; Vandamme, Peter

    2014-08-18

    Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-spoilage bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid bacteria (AAB) and lactic acid bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-spoilage bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of spoilage bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Luo, Yi; Rudy, Jeffrey A; Uboh, Cornelius E; Soma, Lawrence R; Guan, Fuyu; Enright, James M; Tsang, Deborah S

    2004-03-05

    The method describes quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC/Q-TOF/MS/MS). Samples were screened by enzyme-linked immunosorbent assay (ELISA) and only those samples presumptively declared positive were subjected to quantification and confirmation for the presence of flunixin by this method. The method is also readily adaptable to instrumental screening for the analyte. Flunixin was recovered from plasma by liquid-liquid extraction (LLE). The sample was diluted with 2 ml saturated phosphate buffer (pH 3.10) prior to LLE. The dried extract was reconstituted in acetonitrile:water:formic acid (50:50:0.1, v/v/v) and subsequently analyzed on a Q-TOF tandem mass spectrometer (Micromass) operated under electrospray ionization positive ion mode. The concentration of flunixin was determined by the internal standard (IS) calibration method using the peak area ratio with clonixin as the IS. The limits of detection (LOD) and quantification (LOQ) for flunixin in equine plasma were 0.1 and 1 ng/ml, respectively, whereas the limit of confirmation (LOC) was 2.5 ng/ml. The qualifying ions for the identification of flunixin were m/z 297 [M+H](+), 279 (BP), 264, 259, 239 and those for clonixin (IS) were m/z 263 [M+H](+), 245 (BP) and 210. The measurement uncertainty about the result was 8.7%. The method is simple, sensitive, robust and reliably fast in the quantification and confirmation of flunixin in equine plasma. Application of this method will assist racing authorities in the enforcement of tolerance plasma concentration of flunixin in the racehorse on race day.

  19. Detection of illicit drugs on surfaces using direct analysis in real time (DART) time-of-flight mass spectrometry.

    Science.gov (United States)

    Grange, Andrew H; Sovocool, G Wayne

    2011-05-15

    Methamphetamine (meth) from meth syntheses or habitual meth smoking deposited on household surfaces poses human health hazards. The U.S. State Departments of Health require decontamination of sites where meth was synthesized (meth labs) before they are sold. National Institute for Occupational Safety and Health (NIOSH) methods for meth analysis require wipe sampling, extraction, clean-up, solvent exchange, derivatization, and/or mass spectral analysis using selected ion monitoring. Rapid and inexpensive analyses could screen for drug-contamination within structures with greater spatial resolution, provide real-time analyses during decontamination, and provide thorough documentation of successful clean ups. Herein an autosampler/open-air ion source time-of-flight mass spectrometric technique is described that required only direct sampling using cotton-swab wipes. Each wipe sample collection required 2 min and data acquisition required only 13 s per sample. Optimum collision-induced dissociation voltages, desorption gas temperatures, and wipe sample solvents were determined for 11 drugs. Peaks were observed in analyte-ion traces for 0.025 µg/100 cm(2) of meth and seven other drugs. This level is half the detection limit of NIOSH methods and one-fourth of the lowest U.S. state decontamination limit for meth. Dynamic ranges of 100 in concentration were demonstrated for eight drugs, which is sufficient for a screening technique. The volatilities of 11 drugs deposited on glass were determined. The pick up of the drugs by solvent-soaked cotton-swab wipes from glass relative to acrylic latex paint was also compared.

  20. Determination of Dicyandiamide in Powdered Milk Using Direct Analysis in Real Time Quadrupole Time-of-Flight Tandem Mass Spectrometry

    Science.gov (United States)

    Zhang, Liya; Yong, Wei; Liu, Jiahui; Wang, Sai; Chen, Qilong; Guo, Tianyang; Zhang, Jichuan; Tan, Tianwei; Su, Haijia; Dong, Yiyang

    2015-08-01

    The direct analysis in real time (DART) ionization source coupled with quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) system has the capability to desorb analytes directly from samples without sample cleanup or chromatographic separation. In this work, a method based on DART/Q-TOF MS/MS has been developed for rapid identification of dicyandiamide (DCD) present in powdered milk. Simple sample extraction procedure employing acetonitrile-water (80:20, v/v) mixture was followed by direct, high-throughput determination of sample extracts spread on a steel mesh of the transmission module by mass spectrometry under ambient conditions. The method has been evaluated for both qualitative and quantitative analysis of DCD in powdered milk. Variables including experimental apparatus, DART gas heater temperature, sample presentation speed, and vacuum pressure were investigated. The quantitative method was validated with respect to linearity, sensitivity, repeatability, precision, and accuracy by using external standards. After optimization of these parameters, a limit of detection (LOD) of 100 μg kg-1 was obtained for DCD with a linear working range from 100 to 10000 μg kg-1 and a satisfactory correlation coefficient (R2) of 0.9997. Good recovery (80.08%-106.47%) and repeatability (RSD = 3.0%-5.4%) were achieved for DCD. The DART/Q-TOF MS/MS-based method provides a rapid, efficient, and powerful scheme to analyze DCD in powdered milk with limited sample preparation, thus reducing time and complexity of quality control.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tarik, Mohamed [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Lotito, Giovanni [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Whitby, James A. [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Koch, Joachim [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Fuhrer, Katrin; Gonin, Marc [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Michler, Johann [Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Bolli, Jean-Luc [Ecole d' ingenieurs de Geneve, 4 Prairie, 1202 Geneva (Switzerland); Guenther, Detlef [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland)], E-mail: guenther@inorg.chem.ethz.ch

    2009-03-15

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

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

    Science.gov (United States)

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

    2009-03-01

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

  3. Characterization of thin film tandem solar cells by radiofrequency pulsed glow discharge - Time of flight mass spectrometry.

    Science.gov (United States)

    Fernandez, Beatriz; Lobo, Lara; Reininghaus, Nies; Pereiro, Rosario; Sanz-Medel, Alfredo

    2017-04-01

    Beside low production costs and the use of nontoxic and abundant raw materials, silicon based thin-film solar cells have the advantage to be built up as multi junction devices like tandem or triple junction solar cells. Silicon thin film modules made of tandem cells with hydrogenated amorphous silicon (a-Si:H) top cell and microcrystalline (μc) Si:H bottom cell are available on the market. In this work, the analytical potential of state-of-the art radiofrequency (rf) pulsed glow discharge (PGD) time of flight mass spectrometry (TOFMS) commercial instrumentation is investigated for depth profiling analysis of tandem-junctions solar cells on 2mm thick glass substrate with 1µm thick ZnO:Al. Depth profile characterization of two thin film tandem photovoltaic devices was compared using millisecond and sub-millisecond rf-PGD regimes, as well as the so-called "low mass mode" available in the commercial instrument used. Two procedures for sample preparation, namely using flat or rough cell substrates, were compared and the distribution of dopant elements (phosphorous, boron and germanium) was investigated in both cases. Experimental results obtained by rf-PGD-TOFMS as well as electrical measurements of the samples showed that a worse depth resolution of dopant elements in the silicon layers (e.g. distribution of boron in a thicker region that suggests a diffusion of this dopant in the coating of the sample) found using a rough sample substrate was related to a higher power conversion efficiency. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Identification of Serum Biomarkers for Biliary Tract Cancers by a Proteomic Approach Based on Time-of-Flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wen-Jing [Department of Molecular Biology for Public Health, Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhong Shan Xi Road, Shanghai, 200336 (China); Xu, Wang-Hong, E-mail: wanghong.xu@fudan.edu.cn [Department of Epidemiology, Shanghai Cancer Institute, 2200/25 Xie Tu Road, Shanghai, 200032 (China); Department of Epidemiology, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University,138 Yi Xue Yuan Road, Shanghai, 200032 (China); Liu, Cha-Zhen [Department of Molecular Biology for Public Health, Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhong Shan Xi Road, Shanghai, 200336 (China); Rashid, Asif [Department of Pathology, MD Anderson Cancer Center, Houston, TX (United States); Cheng, Jia-Rong [Department of Epidemiology, Shanghai Cancer Institute, 2200/25 Xie Tu Road, Shanghai, 200032 (China); Liao, Ping; Hu, Heng [Department of Molecular Biology for Public Health, Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhong Shan Xi Road, Shanghai, 200336 (China); Chu, Lisa W. [Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, Bethesda, MD 20892-7234 (United States); Gao, Yu-Tang [Department of Epidemiology, Shanghai Cancer Institute, 2200/25 Xie Tu Road, Shanghai, 200032 (China); Yu, Kai; Hsing, Ann W. [Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, Bethesda, MD 20892-7234 (United States)

    2010-08-18

    Biliary tract cancers (BTCs) are lethal malignancies currently lacking satisfactory methods for early detection and accurate diagnosis. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is a promising diagnostic tool for this disease. In this pilot study, sera samples from 50 BTCs and 30 cholelithiasis patients as well as 30 healthy subjects from a population-based case-control study were randomly grouped into training set (30 BTCs, 20 cholelithiasis and 20 controls), duplicate of training set, and blind set (20 BTCs, 10 cholelithiasis and 10 controls); all sets were analyzed on Immobilized Metal Affinity Capture ProteinChips via SELDI-TOF-MS. A decision tree classifier was built using the training set and applied to all test sets. The classification tree constructed with the 3,400, 4,502, 5,680, 7,598, and 11,242 mass-to-charge ratio (m/z) protein peaks had a sensitivity of 96.7% and a specificity of 85.0% when comparing BTCs with non-cancers. When applied to the duplicate set, sensitivity was 66.7% and specificity was 70.0%, while in the blind set, sensitivity was 95.0% and specificity was 75.0%. Positive predictive values of the training, duplicate, and blind sets were 82.9%, 62.5% and 79.2%, respectively. The agreement of the training and duplicate sets was 71.4% (Kappa = 0.43, u = 3.98, P < 0.01). The coefficient of variations based on 10 replicates of one sample for the five differential peaks were 15.8–68.8% for intensity and 0–0.05% for m/z. These pilot results suggest that serum protein profiling by SELDI-TOF-MS may be a promising approach for identifying BTCs but low assay reproducibility may limit its application in clinical practice.

  5. Fragmentation pathways of synthetic and naturally occurring coumarin derivatives by ion trap and quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Liang, Xianrui; Han, Xiaomei

    2015-09-15

    Synthetic and natural coumarin derivatives possess a wide range of biological activities. Fragmentation pathway studies are important in identifying both naturally occurring coumarins and synthetic coumarins with novel structures and properties. The fragmentation pathways of eleven coumarin derivatives are investigated by electrospray ionization (ESI) ion-trap mass spectrometry (ESI-ITMS(n) ) and ESI quadrupole time-of-flight mass spectrometry (QTOFMS) in positive mode. Compounds 1-9 in this study were newly synthesized in our laboratory. Compounds 10 and 11 were isolated from the root of Zanthoxylum armatum. The major fragmentation pathways for 11 coumarin derivatives are greatly affected by the heterocyclic ring structures and the side-chain substituents. Typical losses of small neutral molecules, such as CH3 CH2 OH, CH2 =CH2 , CO, and H2 O, are observed for compounds 1-5. Compounds 6-9 share similar fragmentation pathways through losses of CO, aromatic rings, and the coumarin skeleton. The main product ions at m/z 205, 219, and 220 observed for compounds 10 and 11 are produced by the loss of C5 H12 O2 , C4 H10 O2 , and the C4 H9 O2 radical, respectively. The fragmentation pathways of 11 coumarin derivatives are elucidated based on ITMS(n) and QTOFMS spectral data. Differences in the structures of the heterocyclic rings and side-chain substituents strongly affect the fragmentation pathways of the coumarins. The present results will facilitate further research into the fragmentation pathways and structural characterization of these classes of compounds with diverse structures. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Supra-aortic low-dose contrast-enhanced time-resolved magnetic resonance (MR) angiography at 3 T: comparison with time-of-flight MR angiography and high-resolution contrast-enhanced MR angiography.

    Science.gov (United States)

    Lee, Youn-Joo; Kim, Bum-soo; Koo, Ja-Sung; Kim, Bom-Yi; Jang, Jinhee; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin

    2015-06-01

    Low-dose, time-resolved, contrast-enhanced, magnetic resonance angiography (TR-CEMRA) has been described previously; however, a comparative study between low dose TR-CEMRA and time-of-flight MRA (TOF-MRA) in the diagnosis of supra-aortic arterial stenosis has not yet been published. To demonstrate the feasibility and effectiveness of low-dose TR-CEMRA compared with TOF-MRA, using high-resolution contrast-enhanced MRA (HR-CEMRA) as the reference standard. This prospective study consisted of 30 consecutive patients. All patients underwent TOF-MRA of the neck and circle of Willis and supra-aortic HR-CEMRA, followed by supra-aortic low-dose TR-CEMRA. Gadoterate meglumine (Gd-DOTA, Dotarem(®), Guerbet, Roissy CdG Cedex, France) was injected at a dose of 0.1 mmol/kg for HR-CEMRA, followed by a 0.03 mmol/kg bolus for low-dose TR-CEMRA. Three readers evaluated the assessibility and image quality, and then two readers classified each stenosis into the following categories: normal (0-30%), mild stenosis (31-50%), moderate (51-70%), severe (71-99%), and occlusion. TR-CEMRA and HR-CEMRA showed a greater number of assessable arterial segments than TOF-MRA (P < 0.01). For TR-CEMRA, 29 cases showed within or better than the diagnostic range, whereas all 30 cases were in the diagnostic range for TOF-MRA and HR-CEMRA. For evaluation of stenosis in a total of 743 arterial segments, both TR-CEMRA and TOF-MRA results agreed with those of HR-CEMRA in 729 segments (98.1%), with excellent inter-observer agreement of TR-CEMRA; stenosis was overestimated in nine segments (1.2%) and underestimated in five segments (0.7%). For diagnosis of stenosis using 30% as the cut-off value on HR-CEMRA, the sensitivity and specificity were 88.2% and 99.3%, respectively, for the TR-CEMRA procedure, versus 94.1% and 99.6%, respectively, for TOF-MRA. Low-dose TR-CEMRA is feasible and effective in the diagnosis of supra-aortic arterial stenosis, and could be more useful option than TOF-MRA. © The

  7. 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

  8. Characterisation of volatile components of Pinotage wines using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC–TOFMS)

    NARCIS (Netherlands)

    Weldegergis, B.T.; Villiers, de A.; McNeish, C.; Seethapathy, S.; Mostafa, A.; Górecki, T.; Crouch, A.M.

    2011-01-01

    As part of the ongoing research into the chemical composition of the uniquely South African wine cultivar Pinotage, the volatile composition of nine young wines of this cultivar was investigated using comprehensive two-dimensional gas chromatography (GC × GC) in combination with time-of-flight mass

  9. 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

  10. Validation of a qualitative screening method for pesticides in fruits and vegetables by gas chromatography quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization

    NARCIS (Netherlands)

    Portoles, T.; Mol, J.G.J.; Sancho, J.V.; Lopez, F.J.; Hernandez, F.

    2014-01-01

    A wide-scope screening method was developed for the detection of pesticides in fruit and vegetables. The method was based on gas chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer with an atmospheric pressure chemical ionization source (GC-(APCI)QTOF MS). A non-target acq

  11. Characterization of olive oil volatiles by multi-step direct thermal desorption-comprehensive gas chromatography-time-of-flight mass spectrometry using a programmed temperature vaporizing injector

    NARCIS (Netherlands)

    de Koning, S.; Kaal, E.; Janssen, H.-G.; van Platerink, C.; Brinkman, U.A.Th.

    2008-01-01

    The feasibility of a versatile system for multi-step direct thermal desorption (DTD) coupled to comprehensive gas chromatography (GC × GC) with time-of-flight mass spectrometric (TOF-MS) detection is studied. As an application the system is used for the characterization of fresh versus aged olive oi

  12. Identification of Wheat Varieties Using Matrix-assisted Laser Desorption/Ionisation Time-of-flight Mass Spectrometry and an Artificial Neural network

    DEFF Research Database (Denmark)

    Bloch, Helle Aagaard; Kesmir, Can; Petersen, Marianne Kjerstine;

    1999-01-01

    A novel tool for variety identification of wheat (Triticum aestivum L,) has been developed: an artificial neural network (ANN) is used to classify the gliadin fraction analysed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). The robustness...

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

    Science.gov (United States)

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

    2011-01-01

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

  14. Characterisation of volatile components of Pinotage wines using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC–TOFMS)

    NARCIS (Netherlands)

    Weldegergis, B.T.; Villiers, de A.; McNeish, C.; Seethapathy, S.; Mostafa, A.; Górecki, T.; Crouch, A.M.

    2011-01-01

    As part of the ongoing research into the chemical composition of the uniquely South African wine cultivar Pinotage, the volatile composition of nine young wines of this cultivar was investigated using comprehensive two-dimensional gas chromatography (GC × GC) in combination with time-of-flight mass

  15. Differentiation of Raoultella ornithinolytica/planticola and Klebsiella oxytoca clinical isolates by matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

    NARCIS (Netherlands)

    Jong, Eefje de; Jong, A.S. de; Smidts-van den Berg, N.; Rentenaar, R.J.

    2013-01-01

    Ninety-nine clinical isolates previously identified as Klebsiella oxytoca were evaluated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Eight isolates were identified as Raoultella spp., being 5 Raoultella spp. and 3 K. oxytoca, by 16S rRNA sequenc

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

    Science.gov (United States)

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

    2011-01-01

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

  17. Differentiation of Clinically Relevant mucorales Rhizopus microsporus and R. arrhizus by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS)

    NARCIS (Netherlands)

    Dolatabadi, S.; Kolecka, A.; Versteeg, Matthijs; de Hoog, Sybren G; Boekhout, Teun

    2015-01-01

    This study addresses the usefulness of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) for reliable identification of the two most frequently occuring clinical species of Rhizopus, namely R. arrhizus with its two varieties arrhizus and delemar and R. micro

  18. A new matching algorithm for high resolution mass spectra

    DEFF Research Database (Denmark)

    Hansen, Michael Edberg; Smedsgaard, Jørn

    2004-01-01

    We present a new matching algorithm designed to compare high-resolution spectra. Whereas existing methods are bound to compare fixed intervals of ion masses, the accurate mass spectrum (AMS) distance method presented here is independent of any alignment. Based on the Jeffreys-Matusitas (JM......) distance, a difference between observed peaks across pairs of spectra can be calculated, and used to find a unique correspondence between the peaks. The method takes into account that there may be differences in resolution of the spectra. The algorithm is used for indexing in a database containing 80...... accurate mass spectra from an analysis of extracts of 80 isolates representing the nine closely related species in the Penicillium series Viridicata. Using this algorithm we can obtain a retrieval performance of approximate to97-98% that is comparable with the best of the existing methods (e.g., the dot...

  19. Detection of an extended human volatome with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Michael Phillips

    Full Text Available BACKGROUND: Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF MS has been proposed as a powerful new tool for multidimensional analysis of complex chemical mixtures. We investigated GCxGC-TOF MS as a new method for identifying volatile organic compounds (VOCs in normal human breath. METHODS: Samples of alveolar breath VOCs and ambient room air VOC were collected with a breath collection apparatus (BCA onto separate sorbent traps from 34 normal healthy volunteers (mean age = 40 yr, SD = 17 yr, male/female = 19/15. VOCs were separated on two serial capillary columns separated by a cryogenic modulator, and detected with TOF MS. The first and second dimension columns were non-polar and polar respectively. RESULTS: BCA collection combined with GC×GC-TOF MS analysis identified approximately 2000 different VOCs in samples of human breath, many of which have not been previously reported. The 50 VOCs with the highest alveolar gradients (abundance in breath minus abundance in ambient room air mostly comprised benzene derivatives, acetone, methylated derivatives of alkanes, and isoprene. CONCLUSIONS: Collection and analysis of breath VOCs with the BCA-GC×GC-TOF MS system extended the size of the detectable human volatile metabolome, the volatome, by an order of magnitude compared to previous reports employing one-dimensional GC-MS. The size of the human volatome has been under-estimated in the past due to coelution of VOCs in one-dimensional GC analytical systems.

  20. Untargeted metabolomic analysis using liquid chromatography quadrupole time-of-flight mass spectrometry for non-volatile profiling of wines

    Energy Technology Data Exchange (ETDEWEB)

    Arbulu, M. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Sampedro, M.C. [Central Service of Analysis, SGIker, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Gómez-Caballero, A.; Goicolea, M.A. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Barrio, R.J., E-mail: r.barrio@ehu.es [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain)

    2015-02-09

    Highlights: • An untargeted metabolomic method for the non-volatile profile of the Graciano wine was developed. • 411 different metabolites in Graciano Vitis vinifera red wine were identified. • 15 compounds could serve to differentiate Graciano and Tempranillo wines. • An enological database (WinMet) with 2080 compounds was constructed. - Abstract: The current study presents a method for comprehensive untargeted metabolomic fingerprinting of the non-volatile profile of the Graciano Vitis vinifera wine variety, using liquid chromatography/electrospray ionization time of flight mass spectrometry (LC–ESI-QTOF). Pre-treatment of samples, chromatographic columns, mobile phases, elution gradients and ionization sources, were evaluated for the extraction of the maximum number of metabolites in red wine. Putative compounds were extracted from the raw data using the extraction algorithm, molecular feature extractor (MFE). For the metabolite identification the WinMet database was designed based on electronic databases and literature research and includes only the putative metabolites reported to be present in oenological matrices. The results from WinMet were compared with those in the METLIN database to evaluate how much the databases overlap for performing identifications. The reproducibility of the analysis was assessed using manual processing following replicate injections of Vitis vinifera cv. Graciano wine spiked with external standards. In the present work, 411 different metabolites in Graciano Vitis vinifera red wine were identified, including primary wine metabolites such as sugars (4%), amino acids (23%), biogenic amines (4%), fatty acids (2%), and organic acids (32%) and secondary metabolites such as phenols (27%) and esters (8%). Significant differences between varieties Tempranillo and Graciano were related to the presence of fifteen specific compounds.

  1. Identification of in vitro metabolites of ethylphenidate by liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Negreira, Noelia; Erratico, Claudio; van Nuijs, Alexander L N; Covaci, Adrian

    2016-01-05

    Ethylphenidate is a new potent synthetic psychoactive drug, structurally related to methylphenidate. Using human liver microsomes and cytosol, we have investigated for the first time the Phase-I and Phase-II in vitro metabolism of ethylphenidate. The structure of the metabolites was elucidated by hybrid quadrupole time-of-flight mass spectrometry. Overall, seven Phase-I, but no Phase-II metabolites were detected. Ethylphenidate underwent hydroxylation forming two primary mono-hydroxylated metabolites and, subsequently, dehydration and ring opening with an additional hydroxylation, forming secondary metabolites. The involvement of different human cytochrome P450 (CYP) enzymes in the formation of ethylphenidate metabolites was investigated using a panel of human recombinant CYPs (rCYPs). rCYP2C19 was the most active recombinant enzyme involved in the formation of all seven ethylphenidate metabolites detected, although other rCYPs (rCYP1A2, rCYP2B6, rCYPC9, rCYP2D6, and rCYP3A4, but not rCYP2E1) played a role in the metabolism of ethylphenidate. All metabolites identified in the present study can be considered as potential specific biomarkers of ethylphenidate in toxicological studies. Additionally, ritalinic acid and methylphenidate were formed by non-enzymatic hydrolysis and trans-esterification, and, therefore, they cannot be considered as (oxidative) metabolites of ethylphenidate. The presence of methylphenidate and ritalinic acid cannot be exclusively associated to the use of ethylphenidate, since methylphenidate is a drug itself and ritanilic acid can be formed from both ethylphenidate and methylphenidate.

  2. Probing orientation of immobilized humanized anti-lysozyme variable fragment by time-of-flight secondary-ion mass spectrometry.

    Science.gov (United States)

    Baio, J E; Cheng, Fang; Ratner, Daniel M; Stayton, Patrick S; Castner, David G

    2011-04-01

    As methods to orient proteins are conceived, techniques must also be developed that provide an accurate characterization of immobilized protein orientation. In this study, X-ray photoelectron spectroscopy (XPS), surface plasmon resonance (SPR), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to probe the orientation of a surface immobilized variant of the humanized anti-lysozyme variable fragment (HuLys Fv, 26 kDa). This protein contained both a hexahistidine tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo(ethylene glycol) (MEG)-terminated substrates, respectively. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his-tag selectively binds to the Ni-loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. SPR results showed a 10-fold difference in lysozyme binding between the two different HuLys Fv orientations. The ToF-SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv (histidine: 81, 82, and 110 m/z; phenylalanine: 120 and 131 m/z). An intensity ratio of the secondary ion peaks from the histidine and phenylalanine residues at either end of the protein was then calculated directly from the ToF-SIMS data. The 45% change in this ratio, observed between the NTA and MEG substrates with similar HuLys Fv surface coverages, indicates that the HuLys Fv fragment has opposite orientations on two different surfaces.

  3. Laser desorption ionization-time-of-flight mass analysis of perfluoropolyether monolayer directly from hard disk medium surface.

    Science.gov (United States)

    Kudo, Toshiji; Macht, Marcus; Kuroda, Masami

    2011-07-15

    Modern life is dependent on computer technology, and because the volume of digital data in the world is increasing rapidly, the importance of data storage devices is also increasing rapidly. Among them, demands for magnetic disk drive well-known as hard disk drives is quite huge and information recording density on the disk media is continuing to grow dramatically. For the research and development of the magnetic disk media, it is critical to investigate and characterize the lubricant layer formed on the disk media surface. However, it is difficult because the layer is only a monolayer which has only approximately 1 nm thickness in many cases. Although matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) measurements of monolayers have already been reported (Su, J.; Mrksich, M. Langmuir, 2003, 19, 4867-4870), lubricants used here are (co)polymers which have molecular weight distributions and are mixtures of various degrees of polymerization. This can reduce the sensitivity of MS measurement because the number (or density) of distinct single molecular species is lower than for homogeneous samples. In this report, direct measurement and characterization of lubricant monolayers using the LDI-TOF-MS instrument is performed to gain insight into detailed information like average molecular weight, polymer distribution, and two-dimensional mapping directly from magnetic disk monolayers. To our knowledge, this is the first time such information was acquired directly from hard disk media. The technique reported here might open up new possibilities also for investigations of various electronic devices other than magnetic hard disks.

  4. Multicapillary gas chromatography coupled to inductively coupled plasma-time-of-flight mass spectrometry for rapid mercury speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jitaru, Petru; Goenaga Infante, Heidi; Adams, Freddy C

    2003-08-11

    A simple, rapid and accurate method on the basis of multicapillary gas chromatography (MCGC) combined with inductively coupled plasma-time-of-flight mass spectrometry (ICP-TOFMS) was developed for speciation analysis of methylmercury (MeHg{sup +}) and inorganic mercury (Hg{sup 2+}). The potential of the ICP-TOFMS for transient multi-isotope detection of very short signals (peak width of 0.4 s at half peak height) was evaluated. Two injection systems (purge-and-trap (PTI) and split (SI) injections) were compared in terms of species separation resolution and transient signal profile. Using purge-and-trap injection, after in situ derivatization of the ionic mercury species with sodium tetraethylborate, a baseline separation of MeHg{sup +} and Hg{sup 2+} was achieved within a chromatographic run of <35 s. To correct for matrix-induced ion signal variation and instrumental drift, propylmercury (PrHg{sup +}) was used as internal standard. Detection limits of 16 and 257 fg g{sup -1} for MeHg{sup +} (as Hg) and Hg{sup 2+}, respectively, were achieved. The analytical precision (R.S.D. (%)) for 10 successive injections of a standard mixture containing 10 pg MeHg{sup +} (as Hg) and Hg{sup 2+} was 1.2% for MeHg{sup +} and 4.1% for Hg{sup 2+}. The method was validated by analysis of two biological certified reference materials (CRM): a dogfish muscle (DORM-2) and a freeze-dried tuna fish (CRM 464)

  5. Liquid chromatography time of flight mass spectrometry based environmental metabolomics for the analysis of Pseudomonas putida Bacteria in potable water.

    Science.gov (United States)

    Kouremenos, Konstantinos A; Beale, David J; Antti, Henrik; Palombo, Enzo A

    2014-09-01

    Water supply biofilms have the potential to harbour waterborne diseases, accelerate corrosion, and contribute to the formation of tuberculation in metallic pipes. One particular species of bacteria known to be found in the water supply networks is Pseudomonas sp., with the presence of Pseudomonas putida being isolated to iron pipe tubercles. Current methods for detecting and analysis pipe biofilms are time consuming and expensive. The application of metabolomics techniques could provide an alternative method for assessing biofilm risk more efficiently based on bacterial activity. As such, this paper investigates the application of metabolomic techniques and provides a proof-of-concept application using liquid chromatography coupled with time-of-flight mass spectrometry (LC-ToF-MS) to three biologically independent P. putida samples, across five different growth conditions exposed to solid and soluble iron (Fe). Analysis of the samples in +ESI and -ESI mode yielded 887 and 1789 metabolite features, respectively. Chemometric analysis of the +ESI and -ESI data identified 34 and 39 significant metabolite features, respectively, where features were considered significant if the fold change was greater than 2 and obtained a p-value less than 0.05. Metabolite features were subsequently identified according to the Metabolomics Standard Initiative (MSI) Chemical Analysis Workgroup using analytical standards and standard online LC-MS databases. Possible markers for P. putida growth, with and without being exposed to solid and soluble Fe, were identified from a diverse range of different chemical classes of metabolites including nucleobases, nucleosides, dipeptides, tripeptides, amino acids, fatty acids, sugars, and phospholipids. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Effect of heating strategies on whey protein denaturation--Revisited by liquid chromatography quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Akkerman, M; Rauh, V M; Christensen, M; Johansen, L B; Hammershøj, M; Larsen, L B

    2016-01-01

    Previous standards in the area of effect of heat treatment processes on milk protein denaturation were based primarily on laboratory-scale analysis and determination of denaturation degrees by, for example, electrophoresis. In this study, whey protein denaturation was revisited by pilot-scale heating strategies and liquid chromatography quadrupole time-of-flight mass spectrometer (LC/MC Q-TOF) analysis. Skim milk was heat treated by the use of 3 heating strategies, namely plate heat exchanger (PHE), tubular heat exchanger (THE), and direct steam injection (DSI), under various heating temperatures (T) and holding times. The effect of heating strategy on the degree of denaturation of β-lactoglobulin and α-lactalbumin was determined using LC/MC Q-TOF of pH 4.5-soluble whey proteins. Furthermore, effect of heating strategy on the rennet-induced coagulation properties was studied by oscillatory rheometry. In addition, rennet-induced coagulation of heat-treated micellar casein concentrate subjected to PHE was studied. For skim milk, the whey protein denaturation increased significantly as T and holding time increased, regardless of heating method. High denaturation degrees were obtained for T >100°C using PHE and THE, whereas DSI resulted in significantly lower denaturation degrees, compared with PHE and THE. Rennet coagulation properties were impaired by increased T and holding time regardless of heating method, although DSI resulted in less impairment compared with PHE and THE. No significant difference was found between THE and PHE for effect on rennet coagulation time, whereas the curd firming rate was significantly larger for THE compared with PHE. Micellar casein concentrate possessed improved rennet coagulation properties compared with skim milk receiving equal heat treatment.

  7. Spatial analysis of time of flight-secondary ion mass spectrometric images by ordinary kriging and inverse distance weighted interpolation techniques.

    Science.gov (United States)

    Milillo, Tammy M; Gardella, Joseph A

    2008-07-01

    Ordinary kriging and inverse distance weighted (IDW) are two interpolation methods for spatial analysis of data and are commonly used to analyze macroscopic spatial data in the fields of remote sensing, geography, and geology. In this study, these two interpolation techniques were compared and used to analyze microscopic chemical images created from time of flight-secondary ion mass spectrometry images from a patterned polymer sample of fluorocarbon (C(x)F(y)) and poly(aminopropyl siloxane) (APS, a.k.a. siloxane). Data was eliminated from the original high-resolution data set by successive random removal, and the image file was interpolated and reconstructed with a random subset of points using both methods. The statistical validity of the reconstructed image was determined by both standard geographic information system (GIS) validation statistics and evaluating the resolution across an image boundary using ASTM depth and image resolution methodology. The results show that both ordinary kriging and IDW techniques can be used to accurately reconstruct an image using substantially fewer sample points than the original data set. Ordinary kriging performed better than the IDW technique, resulting in fewer errors in predicted intensities and greater retention of original image features. The size of the data set required for the most accurate reconstruction of the original image is directly related to the autocorrelation present within the data set. When 10% of the original siloxane data set was used for an ordinary kriging interpolation, the resulting image still retained the characteristic gridlike pattern. The C(x)F(y) data set exhibited stronger spatial correlation, resulting in reconstruction of the image with only 1% of the original data set. The removal of data points does result in a loss of image resolution; however, the resolution loss is not directly related to the percentage of sample points removed.

  8. Sensitivity and fragmentation calibration of the time-of-flight mass spectrometer RTOF on board ESA's Rosetta mission

    Science.gov (United States)

    Gasc, Sébastien; Altwegg, Kathrin; Jäckel, Annette; Le Roy, Léna; Rubin, Martin; Fiethe, Björn; Mall, Urs; Rème, Henri

    2014-05-01

    The European Space Agency's Rosetta mission will rendez-vous comet 67P/Churyumov-Gerasimenko (67P) in September 2014. The Rosetta spacecraft with the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) onboard will follow and survey 67P for more than a year until the comet reaches its perihelion and beyond. ROSINA will provide new information on the global molecular, elemental, and isotopic composition of the coma [1]. ROSINA consists of a pressure sensor (COPS) and two mass spectrometers, the Double Focusing Mass Spectrometer (DFMS) and the Reflectron Time Of Flight mass spectrometer (RTOF). RTOF has a wide mass range, from 1 amu/e to >300 amu/e, and contains two ion sources, a reflectron and two detectors. The two ion sources, the orthogonal and the storage source, are capable to measure cometary ions while the latter also allows measuring cometary neutral gas. In neutral gas mode the ionization is performed through electron impact. A built-in Gas Calibration Unit (GCU) contains a known gas mixture composed of He, CO2, and Kr that can be used for in-flight calibration of the instrument. Among other ROSINA specific scientific goals, RTOF's task will be to determine molecular composition of volatiles via measuring and separating heavy hydrocarbons; it has been designed to study the development of the cometary activity as well as the coma chemistry between 3.5 AU and perihelion. From the spectroscopic studies and in-situ observations of other comets, we expect to find molecules such as H2O, CO, CO2, hydrocarbons, alcohols, formaldehyde, and other organic compounds in the coma of 67P/Churyumov-Gerasimenko [2]. To demonstrate and quantify the sensitivity and functionality of RTOF, calibration measurements have been realized with more than 20 species among the most abundant molecules quoted above, as well as other species such as PAHs. We will describe the applied methods used to realize this calibration and will discuss our preliminary results, i

  9. Appropriate choice of collision-induced dissociation energy for qualitative analysis of notoginsenosides based on liquid chromatography hybrid ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Guang-Ji; Fu, Han-Xu; Xiao, Jing-Cheng; Ye, Wei; Rao, Tai; Shao, Yu-Hao; Kang, Dian; Xie, Lin; Liang, Yan

    2016-04-01

    Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possessesd both the MS(n) ability of ion trap and the excellent resolution of a time-of-flight, and has been widely used to identify drug metabolites and determine trace multi-components for in natural products. Collision energy, one of the most important factors in acquiring MS(n) information, could be set freely in the range of 10%-400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides authentic standards were obtained based on accurate MS(2) and MS(3) measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. Then the extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract, which were produced under a series of collision energies and, were compared to screen out the optimum collision energies values for MS(2) and MS(3). The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS(2) collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. BesidesAddtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS(3) stage.

  10. Rapid Analysis of Components in Coptis chinensis Franch by Ultra-Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Tian, Peng-peng; Zhang, Xiao-xu; Wang, Hong-ping; Li, Pu-ling; Liu, Yu-xin; Li, Shao-jing

    2017-01-01

    Background: Coptis chinensis Franch is a traditional Chinese medical herb. Objective: In this article, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to rapidly, qualitatively, and comprehensively identify the components in Coptis chinensis Franch. Materials and Methods: Chromatographic separation was achieved on an Agilent Zorbax RRHD Eclipse Plus C18 column. The mobile phase consisted of 0.1% formic acid water (A) and 0.1% formic acid acetonitrile (B) with a gradient program. Qualitative analysis was performed on an Agilent 6540 quadrupole time-of-flight mass spectrometer, which was equipped with a Dual AJS ESI source operating in negative mode. Results: A total of 30 alkaloid and non-alkaloid components of Coptis chinensis Franch were identified in only 14 min. Conclusion: This study helped to provide a basis for the quality control of Coptis chinensis Franch. SUMMARY Qualitative analysis method of chlorogenic alkaloids and non-alkaloids in Coptis chinensis Franch is developed by Ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) method.Established UPLC-Q-TOF-MS/MS analysis method is validated with rapidness and accuracy.The developed method was successfully applied for qualitative analysis of Coptis chinensis Franch sample collected from cultivation place in China. Abbreviations used: Q-TOF-MS: quadrupole time-of-flight mass spectrometry, UPLC: ultra-performance liquid chromatography, pos: positive, neg: negative. Q-TOF-MS: quadrupole time-of-flight mass spectrometry, UPLC: ultra-performance liquid chromatography, pos: positive, neg: negative. UPLC: ultra-performance liquid chromatography, pos: positive, neg: negative. pos: positive, neg: negative. neg: negative. PMID:28216903

  11. High Resolution Studies of Mass Loss from Massive Binary Stars

    Science.gov (United States)

    Corcoran, Michael F.; Gull, Theodore R.; Hamaguchi, Kenji; Richardson, Noel; Madura, Thomas; Post Russell, Christopher Michael; Teodoro, Mairan; Nichols, Joy S.; Moffat, Anthony F. J.; Shenar, Tomer; Pablo, Herbert

    2017-01-01

    Mass loss from hot luminous single and binary stars has a significant, perhaps decisive, effect on their evolution. The combination of X-ray observations of hot shocked gas embedded in the stellar winds and high-resolution optical/UV spectra of the cooler mass in the outflow provides unique ways to study the unstable process by which massive stars lose mass both through continuous stellar winds and rare, impulsive, large-scale mass ejections. The ability to obtain coordinated observations with the Hubble Space Telescope Imaging Spectrograph (HST/STIS) and the Chandra High-Energy Transmission Grating Spectrometer (HETGS) and other X-ray observatories has allowed, for the first time, studies of resolved line emisssion over the temperature range of 104- 108K, and has provided observations to confront numerical dynamical models in three dimensions. Such observations advance our knowledge of mass-loss asymmetries, spatial and temporal variabilities, and the fundamental underlying physics of the hot shocked outflow, providing more realistic constraints on the amount of mass lost by different luminous stars in a variety of evolutionary stages. We discuss the impact that these joint observational studies have had on our understanding of dynamical mass outflows from massive stars, with particular emphasis on two important massive binaries, Delta Ori Aa, a linchpin of the mass luminosity relation for upper HRD main sequence stars, and the supermassive colliding wind binary Eta Carinae.

  12. Rapid screening and identification of lycodine-type alkaloids in Lycopodiaceae and Huperziaceae plants by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Shan, Si-Ming; Luo, Jian-Guang; Pan, Ke; Zou, Hong-Yan; Kong, Ling-Yi

    2016-11-01

    Lycodine-type alkaloids have gained significant interest owing to their unique skeletal characteristics and acetylcholinesterase activity. This study established a rapid and reliable method using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q/TOF-MS/MS) for comprehensive characterization of lycodine-type alkaloids for the first time. The lycodine-type alkaloids were detected successfully from Lycopodiastrum casuarinoides, Huperzia serrata and Phlegmarirus carinatus in seven plants of the Lycopodiaceae and Huperziaceae families, based on the established characteristic MS fragmentation of five known alkaloids. Furthermore, a total of 13 lycodine-type alkaloids were identified, of which three pairs of isomers were structurally characterized and differentiated. This study further improves mass analysis of lycodine-type alkaloids and demonstrates the superiority of UPLC with a high-resolution mass spectrometer for the rapid and sensitive structural elucidation of other trace active compounds. Copyright © 2016 John Wiley & Sons, Ltd.

  13. ALICE Time Of Flight Detector

    CERN Multimedia

    Alici, A

    2013-01-01

    Charged particles in the intermediate momentum range are identified in ALICE by the Time Of Flight (TOF) detector. The time measurement with the TOF, in conjunction with the momentum and track length measured by the tracking detector, is used to calculate the particle mass.

  14. Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    A. W. Rollins

    2009-10-01

    Full Text Available Four hydroxynitrates (R(OHR'ONO2 representative of atmospheric volatile organic compound (VOC oxidation products were synthesized, nebulized and sampled into an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS. The resulting mass spectrum was used to evaluate calibration factors for elemental analysis of organic nitrates by AMS, and to determine the distribution of nitrogen in the detected fragments in a search for an AMS signature of organic nitrates. We find that 30% of the detected nitrogen mass is in the NO+ and NO2+ fragments, 12% at NHx+ fragments, 5% at CxHyOzN+ fragments, and 53% at various CxHyN+ fragments. Elemental analysis indicated that nitrogen was detected with higher efficiency than carbon and hydrogen, but oxygen was detected with reduced efficiency compared to previously reported results for a suite of organics which did not include organic nitrates. The results are used to suggest the maximum corrections to ambient O:C and N:C ratios based on AMS measurements.

  15. Intact MicroRNA Analysis Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Kullolli, Majlinda; Knouf, Emily; Arampatzidou, Maria; Tewari, Muneesh; Pitteri, Sharon J.

    2014-01-01

    MicroRNAs (miRNAs) are small single-stranded non-coding RNAs that post-transcriptionally regulate gene expression, and play key roles in the regulation of a variety of cellular processes and in disease. New tools to analyze miRNAs will add understanding of the physiological origins and biological functions of this class of molecules. In this study, we investigate the utility of high resolution mass spectrometry for the analysis of miRNAs through proof-of-concept experiments. We demonstrate the ability of mass spectrometry to resolve and separate miRNAs and corresponding 3' variants in mixtures. The mass accuracy of the monoisotopic deprotonated peaks from various miRNAs is in the low ppm range. We compare fragmentation of miRNA by collision-induced dissociation (CID) and by higher-energy collisional dissociation (HCD) which yields similar sequence coverage from both methods but additional fragmentation by HCD versus CID. We measure the linear dynamic range, limit of detection, and limit of quantitation of miRNA loaded onto a C18 column. Lastly, we explore the use of data-dependent acquisition of MS/MS spectra of miRNA during online LC-MS and demonstrate that multiple charge states can be fragmented, yielding nearly full sequence coverage of miRNA on a chromatographic time scale. We conclude that high resolution mass spectrometry allows the separation and measurement of miRNAs in mixtures and a standard LC-MS setup can be adapted for online analysis of these molecules.

  16. Multi-Wavelength Laser Transmitter for the Two-Step Laser Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Yu, Anthony W.; Li, Steven X.; Fahey, Molly E.; Grubisic, Andrej; Farcy, Benjamin J.; Uckert, Kyle; Li, Xiang; Getty, Stephanie

    2017-01-01

    Missions to diverse Outer Solar System bodies will require investigations that can detect a wide range of organics in complex mixtures, determine the structure of selected molecules, and provide powerful insights into their origin and evolution. Previous studies from remote spectroscopy of the Outer Solar System showed a diverse population of macromolecular species that are likely to include aromatic and conjugated hydrocarbons with varying degrees of methylation and nitrile incorporation. In situ exploration of Titan's upper atmosphere via mass and plasma spectrometry has revealed a complex mixture of organics. Similar material is expected on the Ice Giants, their moons, and other Outer Solar System bodies, where it may subsequently be deposited onto surface ices. It is evident that the detection of organics on other planetary surfaces provides insight into the chemical and geological evolution of a Solar System body of interest and can inform our understanding of its potential habitability. We have developed a prototype two-step laser desorption/ionization time-of-flight mass spectrometer (L2MS) instrument by exploiting the resonance-enhanced desorption of analyte. We have successfully demonstrated the ability of the L2MS to detect hydrocarbons in organically-doped analog minerals, including cryogenic Ocean World-relevant ices and mixtures. The L2MS instrument operates by generating a neutral plume of desorbed analyte with an IR desorption laser pulse, followed at a delay by a ultraviolet (UV) laser pulse, ionizing the plume. Desorption of the analyte, including trace organic species, may be enhanced by selecting the wavelength of the IR desorption laser to coincide with IR absorption features associated with vibration transitions of minerals or organic functional groups. In this effort, a preliminary laser developed for the instrument uses a breadboard mid-infrared (MIR) desorption laser operating at a discrete 3.475 µm wavelength, and a breadboard UV

  17. Chemical characterization of bio-oils using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry.

    Science.gov (United States)

    Tessarolo, Nathalia S; dos Santos, Luciana R M; Silva, Raphael S F; Azevedo, Débora A

    2013-03-01

    The liquid product obtained via the biomass flash pyrolysis is commonly called bio-oil or pyrolysis oil. Bio-oils can be used as sources for chemicals or as fuels, primarily in mixtures or emulsions with fossil fuels. A detailed chemical characterization of bio-oil is necessary to determine its potential uses. Such characterization demands a powerful analytical technique such as comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS). Limited chemical information can be obtained from conventional gas chromatography coupled mass spectrometry (GC-MS) because of the large number of compounds and coelutions. Thus, GC×GC-TOFMS was used for the individual identification of bio-oil components from two samples prepared via the flash pyrolysis of empty palm fruit bunch and pine wood chips. To the best of our knowledge, few papers have reported comprehensive two-dimensional gas chromatography (GC×GC) for bio-oil analysis. Many classes of compounds such as phenols, benzenediols, cyclopentenones, furanones, indanones and alkylpyridines were identified. Several coelutions present in the GC-MS were resolved using GC×GC-TOFMS. Many peaks were detected for the samples by GC-MS (~166 and 129), but 631 and 857 were detected by GC×GC-TOFMS, respectively. The GC×GC-TOFMS analyses indicated that the major classes of components (analytes>0.5% relative area) in the two bio-oil samples are ketones, cyclopentenones, furanones, furans, phenols, benzenediols, methoxy- and dimethoxy-phenols and sugars. In addition, esters, aldehydes and pyridines were found for sample obtained from empty palm fruit bunch, while alcohols and cyclopentanediones were found in sample prepared from pine wood chips indicating different composition profiles due to the biomass sources. The elucidation of the composition of empty fruit bunch and pine wood chips bio-oils indicates that these oils are suitable for the production of value-added chemicals. The

  18. Liquid chromatography-quadrupole-time-of-flight mass spectrometry screening procedure for urine samples in forensic casework compared to gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fels, Helena; Dame, Torsten; Sachs, Hans; Musshoff, Frank

    2016-07-04

    This work represents the development, validation, and application of a liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) screening method for the detection of pharmaceutical substances and illicit drugs (acidic, basic, and neutral organic drugs) in urine samples. Time-of-flight mass spectrometry was performed using an LC-Triple TOF 5600 system with electrospray ionization operated in both positive and negative mode, respectively. The limits of detection (LODs), determined for 34 substances, were 70%). These four parameters served as identification criteria and are discussed according to their role in identifying compounds even without reference substances. In routine casework, two in-house XIC (extracted ion chromatogram) lists, consisting of 456 protonated and 26 deprotonated compounds were used and retention times for 365 compounds were available. Compared to the results found with the established gas chromatography-mass spectrometry (GC-MS) procedure, the findings with the LC-QTOF-MS screening method showed a good comparability. Results that were not detected by LC-QTOF-MS because of a missing entry in the targeted XIC list could retrospectively be confirmed by simply entering the elemental formula of the relevant substance into the software and reprocessing the sample. LC-QTOF-MS offers an attractive technique for the fast and specific identification of illicit drugs and toxic compounds in urine samples. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Single particle characterization using a light scattering module coupled to a time-of-flight aerosol mass spectrometer

    Directory of Open Access Journals (Sweden)

    E. S. Cross

    2008-12-01

    Full Text Available We present the first single particle results obtained using an Aerodyne time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS. The instrument was deployed at the T1 ground site approximately 40 km northeast of the Mexico City Metropolitan Area (MCMA as part of the MILAGRO field study in March of 2006. The instrument was operated as a standard AMS from 12–30 March, acquiring average chemical composition and size distributions for the ambient aerosol, and in single particle mode from 27–30 March. Over a 75-h sampling period, 12 853 single particle mass spectra were optically triggered, saved, and analyzed. The correlated optical and chemical detection allowed detailed examination of single particle collection and quantification within the LS-ToF-AMS. The single particle data enabled the mixing states of the ambient aerosol to be characterized within the context of the size-resolved ensemble chemical information.

    The particulate mixing states were examined as a function of sampling time and most of the particles were found to be internal mixtures containing many of the organic and inorganic species identified in the ensemble analysis. The single particle mass spectra were deconvolved, using techniques developed for ensemble AMS data analysis, into HOA, OOA, NH4NO3, (NH42SO4, and NH4Cl fractions. Average single particle mass and chemistry measurements are shown to be in agreement with ensemble MS and PTOF measurements. While a significant fraction of ambient particles were internal mixtures of varying degrees, single particle measurements of chemical composition allowed the identification of time periods during which the ambient ensemble was externally mixed. In some cases the chemical composition of the particles suggested a likely source. Throughout the full sampling period, the ambient ensemble was an external mixture of combustion

  20. Accurate mass analysis of ethanesulfonic acid degradates of acetochlor and alachlor using high-performance liquid chromatography and time-of-flight mass spectrometry

    Science.gov (United States)

    Thurman, E.M.; Ferrer, I.; Parry, R.

    2002-01-01

    Degradates of acetochlor and alachlor (ethanesulfonic acids, ESAs) were analyzed in both standards and in a groundwater sample using high-performance liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. The negative pseudomolecular ion of the secondary amide of acetochlor ESA and alachlor ESA gave average masses of 256.0750??0.0049 amu and 270.0786??0.0064 amu respectively. Acetochlor and alachlor ESA gave similar masses of 314.1098??0.0061 amu and 314.1153??0.0048 amu; however, they could not be distinguished by accurate mass because they have the same empirical formula. On the other hand, they may be distinguished using positive-ion electrospray because of different fragmentation spectra, which did not occur using negative-ion electrospray.

  1. High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

    Science.gov (United States)

    Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias; Helmus, Rick; Knepper, Thomas P.; de Voogt, Pim

    2016-02-01

    High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of an instrument data processor. Highly accurate mass spectral data enabled the calculation of higher-order mass defects. The different plots of MW and the nth-order mass defects (up to n = 3) could aid in assessing the structure of the different repeating units and estimating their absolute and relative number per molecule. The three major repeating units were -C2H4O-, -C2F4O-, and -CF2O-. Tandem MS was used to identify the end groups that appeared to be phosphates, as well as the possible distribution of the repeating units. Reversed-phase HPLC separated of the polymer molecules on the basis of number of nonpolar repeating units. The elucidated structure resembles the structure in the published manufacturer technical data. This analytical approach to the characterization of a PFPE-based formulation can serve as a guide in analyzing not just other PFPE-based formulations but also other fluorinated and non-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health.

  2. Rapid 'de novo' peptide sequencing by a combination of nanoelectrospray, isotopic labeling and a quadrupole/time-of-flight mass spectrometer.

    Science.gov (United States)

    Shevchenko, A; Chernushevich, I; Ens, W; Standing, K G; Thomson, B; Wilm, M; Mann, M

    1997-01-01

    Protein microanalysis usually involves the sequencing of gel-separated proteins available in very small amounts. While mass spectrometry has become the method of choice for identifying proteins in databases, in almost all laboratories 'de novo' protein sequencing is still performed by Edman degradation. Here we show that a combination of the nanoelectrospray ion source, isotopic end labeling of peptides and a quadrupole/ time-of-flight instrument allows facile read-out of the sequences of tryptic peptides. Isotopic labeling was performed by enzymatic digestion of proteins in 1:1 16O/18O water, eliminating the need for peptide derivatization. A quadrupole/time-of-flight mass spectrometer was constructed from a triple quadrupole and an electrospray time-of-flight instrument. Tandem mass spectra of peptides were obtained with better than 50 ppm mass accuracy and resolution routinely in excess of 5000. Unique and error tolerant identification of yeast proteins as well as the sequencing of a novel protein illustrate the potential of the approach. The high data quality in tandem mass spectra and the additional information provided by the isotopic end labeling of peptides enabled automated interpretation of the spectra via simple software algorithms. The technique demonstrated here removes one of the last obstacles to routine and high throughput protein sequencing by mass spectrometry.

  3. Angular and internal state distributions of H2+ generated by (2 + 1) resonance enhanced multiphoton ionization of H2 using time-of-flight mass spectrometry

    Science.gov (United States)

    Perreault, William E.; Mukherjee, Nandini; Zare, Richard N.

    2016-06-01

    We report direct measurement of the anisotropy parameter β for the angular distribution of the photoelectron and photoion in (2 + 1) resonance enhanced multiphoton ionization process of H2 X 1 Σg + (v = 0, J = 0) molecules through the intermediate H2 E,F 1 Σg + (v' = 0, J' = 0) level (λ = 201.684 nm) using a time-of-flight mass spectrometer. The time-of-flight spectra were recorded as the direction of polarization of the ionizing laser was varied with respect to the flight axis of the H2 molecular beam and were fitted to an angular distribution in an appropriately rotated coordinate system with the z-axis oriented along the time-of-flight axis. The anisotropy parameter β was found to be 1.72 ± 0.13 by fitting the time-of-flight spectra and agreed with previous measurements. Using secondary ionization with a delayed laser pulse of different wavelength, we also determined the vibrational energy distribution of the ions, showing that 98% ± 4% of the ions are generated in their ground vibrational state, in agreement with the calculated Franck-Condon factors between the H2 E,F 1 Σg + (v' = 0) and H 2+ X 1 Σg + (v″) vibrational levels.

  4. Angular and internal state distributions of H2 (+) generated by (2 + 1) resonance enhanced multiphoton ionization of H2 using time-of-flight mass spectrometry.

    Science.gov (United States)

    Perreault, William E; Mukherjee, Nandini; Zare, Richard N

    2016-06-01

    We report direct measurement of the anisotropy parameter β for the angular distribution of the photoelectron and photoion in (2 + 1) resonance enhanced multiphoton ionization process of H2 X (1)Σg (+) (v = 0, J = 0) molecules through the intermediate H2 E,F (1)Σg (+) (v' = 0, J' = 0) level (λ = 201.684 nm) using a time-of-flight mass spectrometer. The time-of-flight spectra were recorded as the direction of polarization of the ionizing laser was varied with respect to the flight axis of the H2 molecular beam and were fitted to an angular distribution in an appropriately rotated coordinate system with the z-axis oriented along the time-of-flight axis. The anisotropy parameter β was found to be 1.72 ± 0.13 by fitting the time-of-flight spectra and agreed with previous measurements. Using secondary ionization with a delayed laser pulse of different wavelength, we also determined the vibrational energy distribution of the ions, showing that 98% ± 4% of the ions are generated in their ground vibrational state, in agreement with the calculated Franck-Condon factors between the H2 E,F (1)Σg (+) (v' = 0) and H2 (+) X (1)Σg (+) (v″) vibrational levels.

  5. Photoabsorption and time-of-flight mass spectroscopy for gas-phase trimethyl phosphate following valence shell excitation

    Energy Technology Data Exchange (ETDEWEB)

    Homem, M.G.P.; Rosa, L.F.S.; Farenzena, L.S.; Hasse, A. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Iza, P. [Escuela Superior Politecnica del Litoral, Guayaquil Guaya (Ecuador); Cavasso Filho, R.L. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil); Lee, M.T.; Iga, I. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil)

    2012-07-01

    Full text: In this work we report an experimental study on photoabsorption of trimethyl phosphate (TMP) molecules in the vacuum-ultraviolet energy range. More specifically, absolute photoabsorption cross sections and photoionization yields are measured and reported in the (11.11-21.45) eV energy range. The photoionization and neutral-decay cross sections in absolute scale are also derived and reported. Details of our experimental setup and procedure for cross-section determination can be found in our previous work [1]. Essentially, the measurements were performed using a double-ion-chamber technique [2]. The experimental cross-section results are analyzed in comparison with PES measurements. Oscillator strengths sum rules over the extrapolated experimental data gives a value of 71.6 au for the static dipole polarizability of TMP, which is in excellent agreement with the value of 72.3 au reported in literature. In addition, the ionic dissociation in the same energy range has been studied by time-of-flight mass spectrometry [3]. The detected product cations are C{sub 3}H{sub 9}O{sub 4}P{sup +}, C{sub 3}H{sub 8}O{sub 4}P{sup +}, CH{sub 3}O{sub 4}P{sup +}, C{sub 2}H{sub 6}O{sub 3}P{sup +}, PO{sub 4}{sup +}, CH{sub 5}O{sub 2}P{sup +}, PO{sub 3}{sup +}, and CH{sub 3}{sup +}. The observed ionic branching ratios are converted in absolute scale by using the measured photoionization cross sections. The presence of two ionic metastable states corresponding to the C{sub 3}H{sub 9}O{sub 4}P{sup +} and CH{sub 3}O{sub 4}P{sup +} fragments are reported and their metastable ion mean lives are estimated in (152{+-}5) ns and (248{+-}30) ns. The results and discussion will be presented during the workshop. [1] M. G. P. Homem, P. Iza, L. S. Farenzena, R. L. Cavasso-Filho, M. T. Lee and I. Iga, J. Phys. B: At. Mol. Opt. Phys. 42, 235204 (2009). [2] J. A. R. Samson and Lifeng Yin, J. Opt. Soc. Am B 6, 2326 (1989). [3] F. Burmeister, L. H. Coutinho, R. R. T. Marinho, M. G. P. Homem, M. A

  6. Rapid "breath-print" of liver cirrhosis by proton transfer reaction time-of-flight mass spectrometry. A pilot study.

    Directory of Open Access Journals (Sweden)

    Filomena Morisco

    Full Text Available UNLABELLED: The aim of the present work was to test the potential of Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS in the diagnosis of liver cirrhosis and the assessment of disease severity by direct analysis of exhaled breath. Twenty-six volunteers have been enrolled in this study: 12 patients (M/F 8/4, mean age 70.5 years, min-max 42-80 years with liver cirrhosis of different etiologies and at different severity of disease and 14 healthy subjects (M/F 5/9, mean age 52.3 years, min-max 35-77 years. Real time breath analysis was performed on fasting subjects using a buffered end-tidal on-line sampler directly coupled to a PTR-ToF-MS. Twelve volatile organic compounds (VOCs resulted significantly differently in cirrhotic patients (CP compared to healthy controls (CTRL: four ketones (2-butanone, 2- or 3- pentanone, C8-ketone, C9-ketone, two terpenes (monoterpene, monoterpene related, four sulphur or nitrogen compounds (sulfoxide-compound, S-compound, NS-compound, N-compound and two alcohols (heptadienol, methanol. Seven VOCs (2-butanone, C8-ketone, a monoterpene, 2,4-heptadienol and three compounds containing N, S or NS resulted significantly differently in compensate cirrhotic patients (Child-Pugh A; CP-A and decompensated cirrhotic subjects (Child-Pugh B+C; CP-B+C. ROC (Receiver Operating Characteristic analysis was performed considering three contrast groups: CP vs CTRL, CP-A vs CTRL and CP-A vs CP-B+C. In these comparisons monoterpene and N-compound showed the best diagnostic performance. CONCLUSIONS: Breath analysis by PTR-ToF-MS was able to distinguish cirrhotic patients from healthy subjects and to discriminate those with well compensated liver disease from those at more advanced severity stage. A breath-print of liver cirrhosis was assessed for the first time.

  7. A high-resolution record of Greenland mass balance

    Science.gov (United States)

    McMillan, Malcolm; Leeson, Amber; Shepherd, Andrew; Briggs, Kate; Armitage, Thomas W. K.; Hogg, Anna; Kuipers Munneke, Peter; Broeke, Michiel; Noël, Brice; Berg, Willem Jan; Ligtenberg, Stefan; Horwath, Martin; Groh, Andreas; Muir, Alan; Gilbert, Lin

    2016-07-01

    We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat-2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011-2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high-resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.

  8. High Spatial Resolution Time-of-Flight Secondary Ion Mass Spectrometry for the Masses: A Novel Orthogonal ToF FIB-SIMS Instrument with In Situ AFM

    Directory of Open Access Journals (Sweden)

    James A. Whitby

    2012-01-01

    Full Text Available We describe the design and performance of an orthogonal time-of-flight (TOF secondary ion mass spectrometer that can be retrofitted to existing focused ion beam (FIB instruments. In particular, a simple interface has been developed for FIB/SEM instruments from the manufacturer Tescan. Orthogonal extraction to the mass analyser obviates the need to pulse the primary ion beam and does not require the use of monoisotopic gallium to preserve mass resolution. The high-duty cycle and reasonable collection efficiency of the new instrument combined with the high spatial resolution of a gallium liquid metal ion source allow chemical observation of features smaller than 50 nm. We have also demonstrated the integration of a scanning probe microscope (SPM operated as an atomic force microscope (AFM within the FIB/SEM-SIMS chamber. This provides roughness information, and will also allow true three dimensional chemical images to be reconstructed from SIMS measurements.

  9. A fragmentation study of kaempferol using electrospray quadrupole time-of-flight mass spectrometry at high mass resolution

    Science.gov (United States)

    March, Raymond E.; Miao, Xiu-Sheng

    2004-02-01

    A mass spectrometric method based on the combined use of electrospray ionization, collision-induced dissociation and tandem mass spectrometry at high mass resolution has been applied to an investigation of the structural characterization of protonated and deprotonated kaempferol (3,5,7,4'-tetrahydroxyflavone). Low-energy product ion mass spectra of [M+H]+ ions showed simple fragmentations of the C ring that permitted characterization of the substituents in the A and B rings. In addition, four rearrangement reactions accompanied by losses of C2H2O, CHO[radical sign], CO, and H2O were observed. Low-energy product ion mass spectra of [M-H]- ions showed only four rearrangement reactions accompanied by losses of OH[radical sign], CO, CH2O, and C2H2O. The use of elevated cone voltages permitted observation of product ion mass spectra of selected primary and secondary fragment ions so that each fragment ion reported was observed as a direct product of its immediate precursor ion. Product ion mass spectra examined at high mass resolution allowed unambiguous determination of the elemental composition of fragment ions and resolution of two pairs of isobars. Fragmentation mechanisms and ion structures have been proposed.

  10. Expanding the linear dynamic range for quantitative liquid chromatography-high resolution mass spectrometry utilizing natural isotopologue signals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hanghui, E-mail: Hanghui.Liu@senomyx.com [Senomyx Inc. 4767 Nexus Centre Dr., San Diego, CA 92121 (United States); Lam, Lily; Yan, Lin; Chi, Bert [Senomyx Inc. 4767 Nexus Centre Dr., San Diego, CA 92121 (United States); Dasgupta, Purnendu K., E-mail: Dasgupta@uta.edu [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065 (United States)

    2014-11-19

    Highlights: • Less abundant isotopologue ions were utilized to decrease detector saturation. • A 25–50 fold increase in the upper limit of dynamic range was demonstrated. • Linear dynamic range was expanded without compromising mass resolution. - Abstract: The linear dynamic range (LDR) for quantitative liquid chromatography–mass spectrometry can be extended until ionization saturation is reached by using a number of target isotopologue ions in addition to the normally used target ion that provides the highest sensitivity. Less abundant isotopologue ions extend the LDR: the lower ion abundance decreases the probability of ion detector saturation. Effectively the sensitivity decreases and the upper limit of the LDR increases. We show in this paper that the technique is particularly powerful with a high resolution time of flight mass spectrometer because the data for all ions are automatically acquired, and we demonstrated this for four small organic molecules; the upper limits of LDRs increased by 25–50 times.

  11. Screening and confirmation capabilities of liquid chromatography-time-of-flight mass spectrometry for the determination of 200 multiclass sport drugs in urine.

    Science.gov (United States)

    Domínguez-Romero, Juan C; García-Reyes, Juan F; Lara-Ortega, Felipe J; Molina-Díaz, Antonio

    2015-03-01

    In this article, a screening method for the determination of 200 sport drugs in human urine has been developed using liquid-chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS). The chromatographic separation of the targeted doping agents was carried out by fast liquid chromatography using a C18 column (4.6×50 mm) with 1.8 μm particle size. Accurate mass measurements of the selected ion (typically [M+H](+) and [M-H](-)) along with retention time matching was used for the screening and detection of the targeted species. The proposed methodology comprised also a simple sample treatment stage based on solid-phase extraction (SPE) with polymeric cartridges. The SPE method displayed satisfactory recoveries rates (between 70 and 120%) for the majority of the compounds at both concentration levels tested (2.5 and 25 μg L(-1)). The overall performance of the method was satisfactory with all 200 compounds fulfilling WADA minimum required performance levels (MRPLs), with limits of quantitation lower than 1 μg L(-1) for 80% of the compounds, and showing an appropriate linearity (r(2)>0.99) in most cases. Additionally, the ability of "in-source" collision induced dissociation (CID) for confirmatory purposes was examined using as criterion the presence of two high-resolution ions with relevant abundances for unambiguous confirmation. This stringent criterion was fulfilled for 75% of the species using in-source CID fragmentation. The use of an improved approach based on CID performed on a dedicated collision cell without precursor ion selection (using a Q-TOF) provided at least two ions in all cases with the exception of 2-aminoheptane. Finally, based on the use of diagnostic fragment ions, a workflow for the comprehensive screening and identification of non-targeted compounds (viz. compounds with no primary standards or retention time information available, such as metabolites) has been also examined using rat urine samples. The proposed screening method

  12. Characterization of some synthetic Ru and Ir complexes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Lou, X.; Buijtenen, J. van; Bastiaansen, J.J.A.M.; Waal, B.F.M. de; Langeveld, B.M.W.; Dongen, J.L.J. van

    2005-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was applied to the analysis of Ru(OCOCF 3)2(CO)(PPh3)2, Ru(OCOC 3F7)2(CO)(PPh3)2, Ir(tBuppy)3 and Ir(ppy)2(acac) complexes. A troublesome problem in the MALDI-TOFMS characterization of these metal complexes is

  13. Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry for species identification of nonfermenting Gram-negative bacilli.

    Science.gov (United States)

    Almuzara, Marisa; Barberis, Claudia; Traglia, Germán; Famiglietti, Angela; Ramirez, Maria Soledad; Vay, Carlos

    2015-05-01

    Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) to identify 396 Nonfermenting Gram-Negative Bacilli clinical isolates was evaluated in comparison with conventional phenotypic tests and/or molecular methods. MALDI-TOF MS identified to species level 256 isolates and to genus or complex level 112 isolates. It identified 29 genera including uncommon species. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Differentiation of the Dimorphic Fungal Species Paracoccidioides brasiliensis and Paracoccidioides lutzii

    Science.gov (United States)

    Del Negro, Gilda M. B.; Grenfell, Rafaella C.; Vidal, Monica S. M.; Thomaz, Danilo Y.; de Figueiredo, Dulce S. Y.; Bagagli, Eduardo; Juliano, Luiz; Benard, Gil

    2015-01-01

    Isolates of Paracoccidioides brasiliensis and Paracoccidioides lutzii, previously characterized by molecular techniques, were identified for the first time by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). All isolates were correctly identified, with log score values of >2.0. Thus, MALDI-TOF MS is a new tool for differentiating species of the genus Paracoccidioides. PMID:25631803

  15. Does the Capsule Interfere with Performance of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Cryptococcus neoformans and Cryptococcus gattii?

    Science.gov (United States)

    Grenfell, Rafaella C.; Vidal, Monica S. M.; Giudice, Mauro C.; Del Negro, Gilda M. B.; Juliano, Luiz; Benard, Gil; de Almeida Júnior, João N.

    2015-01-01

    We described the impact of the capsule size for Cryptococcus neoformans and Cryptococcus gattii identification at the species level by Bruker matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). After experimental capsule size modulation, we observed that reducing the capsule size resulted in improved identification by Bruker MALDI-TOF MS across all of the reference strains analyzed. PMID:26659203

  16. Use of time-of-flight mass spectrometry for large screening of organic pollutants in surface waters and soils from a rice production area in Colombia

    OpenAIRE

    Portolés Nicolau, Tania; Hernández Hernández, Félix; Díaz San Pedro, Ramón; Ibáñez Martínez, María; Bustos López, Martha Cristina; Botero Coy, Ana María; Fuentes, C. L.; Peñuela, Gustavo

    2012-01-01

    The irrigate district of Usosaldaña, an important agricultural area in Colombia mainly devoted to rice crop production, is subjected to an intensive use of pesticides. Monitoring these compounds is necessary to know the impact of phytosanitary products in the different environmental compartments. In this work, surface water and soil samples from different sites of this area have been analyzed by applying an analytical methodology for large screening based on the use of time-of-flight mass spe...

  17. Characterization of some synthetic Ru and Ir complexes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Lou, X.; Buijtenen, J. van; Bastiaansen, J.J.A.M.; Waal, B.F.M. de; Langeveld, B.M.W.; Dongen, J.L.J. van

    2005-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was applied to the analysis of Ru(OCOCF 3)2(CO)(PPh3)2, Ru(OCOC 3F7)2(CO)(PPh3)2, Ir(tBuppy)3 and Ir(ppy)2(acac) complexes. A troublesome problem in the MALDI-TOFMS characterization of these metal complexes is

  18. Identification of non-diphtheriae corynebacterium by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Alatoom, Adnan A; Cazanave, Charles J; Cunningham, Scott A; Ihde, Sherry M; Patel, Robin

    2012-01-01

    We evaluated the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry for identification of 92 clinical isolates of Corynebacterium species in comparison to identification using rpoB or 16S rRNA gene sequencing. Eighty isolates (87%) yielded a score of ≥1.700, and all of these were correctly identified to the species level with the exception of Corynebacterium aurimucosum being misidentified as the closely related Corynebacterium minutissimum.

  19. Assessment of Reproducibility of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Bacterial and Yeast Identification

    OpenAIRE

    Westblade, Lars F.; Garner, Omai B.; MacDonald,Karen; Bradford, Constance; Pincus, David H.; Mochon, A. Brian; Jennemann, Rebecca; Manji, Ryhana; Bythrow, Maureen; Lewinski, Michael A.; Burnham, Carey-Ann D.; Ginocchio, Christine C.

    2015-01-01

    Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of clinical bacterial and yeast isolates. However, data describing the reproducibility of MALDI-TOF MS for microbial identification are scarce. In this study, we show that MALDI-TOF MS-based microbial identification is highly reproducible and can tolerate numerous variables, including differences in testing environments, instruments, operators, reagent lots, and ...

  20. Differentiation of Raoultella ornithinolytica/planticola and Klebsiella oxytoca clinical isolates by matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

    Science.gov (United States)

    de Jong, Eefje; de Jong, Arjan S; Smidts-van den Berg, Nathalie; Rentenaar, Rob J

    2013-04-01

    Ninety-nine clinical isolates previously identified as Klebsiella oxytoca were evaluated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Eight isolates were identified as Raoultella spp., being 5 Raoultella spp. and 3 K. oxytoca, by 16S rRNA sequencing. These isolates were correctly identified by applying the 10% differential rule for the MALDI-TOF MS score values. This approach might be useful to discriminate Raoultella species from K. oxytoca.

  1. Influence of Culture Media on Detection of Carbapenem Hydrolysis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Ramos, Ana Carolina; Carvalhaes, Cecília Godoy; Cordeiro-Moura, Jhonatha Rodrigo; Rockstroh, Anna Carolina; Machado, Antonia Maria Oliveira; Gales, Ana Cristina

    2016-07-01

    In this study, we evaluated the influence of distinct bacterial growth media on detection of carbapenemase hydrolysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. False-negative results were observed for OXA-25-, OXA-26-, and OXA-72-producing Acinetobacter baumannii isolates grown on MacConkey agar medium. The other culture media showed 100% sensitivity and 100% specificity for detecting carbapenemase.

  2. High mass resolution, high angular acceptance time-of-flight mass spectroscopy for planetary missions under the Planetary Instrument Definition and Development Program (PIDDP)

    Science.gov (United States)

    Young, David T.

    1991-01-01

    This final report covers three years and several phases of work in which instrumentation for the Planetary Instrument Definition and Development Program (PIDDP) were successfully developed. There were two main thrusts to this research: (1) to develop and test methods for electrostatically scanning detector field-of-views, and (2) to improve the mass resolution of plasma mass spectrometers to M/delta M approximately 25, their field-of-view (FOV) to 360 degrees, and their E-range to cover approximately 1 eV to 50 keV. Prototypes of two different approaches to electrostatic scanning were built and tested. The Isochronous time-of-flight (TOF) and the linear electric field 3D TOF devices were examined.

  3. HCN Polymers: Toward Structure Comprehension Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Bonnet, Jean-Yves; Thissen, Roland; Frisari, Ma; Vuitton, Veronique; Quirico, Eric; Le Roy, Léna; Fray, Nicolas; Cottin, Hervé; Horst, Sarah; Yelle, Roger

    A lot of solar system materials, including cometary ices and Titan aerosols, contain dark matter that can be interpreted as complex nitrogen bearing organic matter [1]. In laboratory experi-ments, HCN polymers are thus analogs of great interest. In fact they may be present in Titan atmosphere and in comet nuclei and then reprocessed as a CN distributed source [2], when ices began to sublimate and ejects from the nucleus organic matter grains [3]. The presence of HCN polymers is suggested because HCN molecule has been directly observed in 1P/Halley comet [4] and others. HCN polymers are also of prebiotic interest [5] as it can form amino acid under hydrolysis conditions. Even if they have been studied during the last decades, their chemical composition and structure are still poorly understood, and a great analytical effort has to be continued. In this way we present a high resolution mass spectrometry (HRMS) and a high resolution tandem mass spectrometry (MS/HRMS) analysis of HCN polymers. It was shown [6] that this is a suitable technique to elucidate composition and structure of the soluble part of tholins analogs of Titan's atmosphere aerosols. HCN polymers have never been studied by HRMS, thus we used a LTQ-Orbitrap XL high resolution mass spectrometer to analyse the HCN polymers. These are produced at LISA by direct polymerisation of pure liquid HCN, catalyzed by ammonia. HCN polymers have been completely dissolved in methanol and then injected in the mass spectrometer by ElectroSpray Ionization (ESI). This atmospheric pressure ionization process produces protonated or deprotonated ions, but it does not fragment molecules. Thus HRMS, allows a direct access to the stoechiometry of all the ionizable molecules present in the samples. Fragmentation analyses (MS/MS) of selected ions have also been performed. Thess analysis provide information about the different chemical fonctionnalities present in HCN poly-mers and also about their structure. Thus we are able to

  4. Laser desorption and time-of-flight mass spectrometry. Fundamentals .Applications; Desorption laser et spectrometrie de masse par temps de vol. Aspects fondamentaux. Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chaurand, P.

    1994-11-01

    Time-of-flight mass spectrometry is a very powerful technique for the analysis of heavy molecular ions (100 000 u and more). The ejection in the gas phase and the ionization of these molecules is now possible through the MALDI technique (Matrix Assisted Laser Desorption Ionization). This technique consists in mixing the heavy molecules to be analysed with a organic matrix which absorbs at the wavelength of the laser. The necessary irradiance are of the order of 10{sup 6} W/cm{sup 2}. In these conditions we have shown that the mass resolutions are optimum and that the relative mass accuracies are of the order of 10{sup -4}. We have also demonstrated that the emission angle of the molecular ions in MALDI depends on the incident angle of the laser light. During the desorption process, the molecular ions are emitted in the opposite direction of the incident laser light. This effect is particularly important for the design of the accelerating stage of the time-of-flight spectrometers. Problems relative to the detection of these heavy molecular ions have been studied in details between 0.5 10{sup 4} m/s and 10{sup 5} m/s. The velocity threshold of the electronic emission is lower than the value of 0.5 10{sup 4} m/s. The relation between the electronic emission and the projectile velocity is complex. Finally, examples on mass identification of C{sub 60} molecules and derivated C{sub 60} are presented. Desorption methods are compared. (author). 32 refs., 34 figs.

  5. Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Maddi, Balakrishna; Panisko, Ellen; Albrecht, Karl; Howe, Daniel

    2016-01-01

    Two-dimensional gas chromatography coupled with time of flight mass spectrometry is a powerful tool for identifying and quantifying components in complex mixtures. It has been used to analyze gasoline, jet fuel, diesel, bio-diesel and organic fraction of bio-crude/bio-oil. In these experiments, the first dimension of separation was non-polar, followed by a polar separation. Aqueous fractions of bio-crude and other aqueous samples have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fraction obtained from hydrothermal liquefaction of algae was characterized by two-dimensional gas chromatography coupled with time of flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column combination. Results from qualitative characterization aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time of flight mass spectrometry are highlighted.

  6. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry characterization of aging effects on the mineral fibers treated with aminopropylsilane and quaternary ammonium compounds

    DEFF Research Database (Denmark)

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.

    2012-01-01

    -resolution spectra is also observed. These results indicate that the concentration of hydrocarbon groups decreases after aging due to the partial removal of the long hydrocarbon chains of the surfactant and mineral oil and/or hydrolysis and segregation of APS to the fiber surface. The principal component analysis......X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to investigate the aging effects on the aminopropylsilane (APS) and quaternary ammonium surfactant-treated mineral fibers. APS-coated mineral fiber samples were treated with cationic surfactant...... and mineral oil and aged at 70 °C temperature and 95% humidity. From quantitative XPS measurements, an increase in the atomic composition of oxygen, nitrogen, and silicon is observed after aging. An increase in the protonated amino groups in the N1s high-resolution spectra and C–N group in the C1s high...

  7. Characterisation of dense non-aqueous phase liquids of coal tar using comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry.

    Science.gov (United States)

    Gauchotte-Lindsay, Caroline; McGregor, Laura; Richards, Phil; Kerr, Stephanie; Glenn, Aliyssa; Thomas, Russell; Kalin, Robert

    2013-04-01

    Comprehensive two-dimensional gas chromatography (GCxGC) is a recently developed analytical technique in which two capillary columns with different stationary phases are placed in series enabling planar resolution of the analytes. The resolution power of GCxGC is one order of magnitude higher than that of one dimension gas chromatography. Because of its high resolution capacity, the use of GCxGC for complex environmental samples such as crude oils, petroleum derivatives and polychlorinated biphenyls mixtures has rapidly grown in recent years. We developed a one-step method for the forensic analysis of coal tar dense non-aqueous phase liquids (DNAPLs) from former manufactured gas plant (FMGP) sites. Coal tar is the by-product of the gasification of coal for heating and lighting and it is composed of thousands of organic and inorganic compounds. Before the boom of natural gases and oils, most towns and cities had one or several manufactured gas plants that have, in many cases, left a devastating environmental print due to coal tar contamination. The fate of coal tar DNAPLs, which can persist in the environment for more than a hundred years, is therefore of crucial interest. The presented analytical method consists of a unique clean-up/ extraction stage by pressurized liquid extraction and a single analysis of its organic chemical composition using GCxGC coupled with time of flight mass spectrometry (TOFMS). The chemical fingerprinting is further improved by derivatisation by N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) of the tar compounds containing -OH functions such as alcohols and carboxylic acids. We present here how, using the logical order of elution in GCxGC-TOFMS system, 1) the identification of never before observed -OH containing compounds is possible and 2) the isomeric selectivity of an oxidation reaction on a DNAPL sample can be revealed. Using samples collected at various FMGP sites, we demonstrate how this GCxGC method enables the simultaneous

  8. Proteogenomic analysis of Mycobacterium smegmatis using high resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    Matthys Gerhardus Potgieter

    2016-04-01

    Full Text Available AbstractBiochemical evidence is vital for accurate genome annotation. The integration of experimental data collected at the proteome level using high resolution mass spectrometry allows for improvements in genome annotation by providing evidence for novel gene models, while validating or modifying others. Here we report the results of a proteogenomic analysis of a reference strain of Mycobacterium smegmatis (mc2155, a fast growing model organism for the pathogenic Mycobacterium tuberculosis - the causative agent for Tuberculosis. By integrating high throughput LC/MS/MS proteomic data with genomic six frame translation and ab initio gene prediction databases, a total of 2887 ORFs were identified, including 2810 ORFs annotated to a Reference protein, and 63 ORFs not previously annotated to a Reference protein. Further, the translational start site (TSS was validated for 558 Reference proteome gene models, while upstream translational evidence was identified for 81. In addition, N-terminus derived peptide identifications allowed for downstream TSS modification of a further 24 gene models. We validated the existence of 6 previously described interrupted coding sequences at the peptide level, and provide evidence for 4 novel frameshift positions. Analysis of peptide posterior error probability (PEP scores indicates high-confidence novel peptide identifications and shows that the genome of M. smegmatis mc2155 is not yet fully annotated. Data are available via ProteomeXchange with identifier PXD003500.

  9. Collisional activation by MALDI tandem time-of-flight mass spectrometry induces intramolecular migration of amide hydrogens in protonated peptides

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J D; Bache, Nicolai; Roepstorff, Peter

    2005-01-01

    Considerable controversy exists in the literature as to the occurrence of intramolecular migration of amide hydrogens upon collisional activation of protonated peptides and proteins. This phenomenon has important implications for the application of CID as an experimental tool to obtain site...... of doubly protonated peptides that the original regioselective deuterium pattern of these peptides is completely erased (Jørgensen, T. J. D., Gårdsvoll, H., Ploug, M., and Roepstorff, P. (2005) Intramolecular migration of amide hydrogens in protonated peptides upon collisional activation. J. Am. Chem. Soc.......127, 2785-2793). Taking further advantage of this unique test system we have now investigated the influence of the charge state and collision energy on the occurrence of scrambling in protonated peptides. Our MALDI tandem time-of-flight experiments clearly demonstrate that complete positional...

  10. Rapid identification of erythrocyte phospholipids in Sprague-Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Pi, Juanjuan; Wu, Xia; Yang, Shitian; Zeng, Pingyan; Feng, Yifan

    2015-03-01

    A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague-Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry with MassLynx(TM) MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time-of-flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub-2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in-house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague-Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.

  11. Quantitative depth profiling of Si{sub 1–x}Ge{sub x} structures by time-of-flight secondary ion mass spectrometry and secondary neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Drozdov, M.N.; Drozdov, Y.N. [Institute for Physics of Microstructures of the Russian Academy of Sciences (IPM RAS), 603950 Nizhniy Novgorod (Russian Federation); Lobachevski Nizhniy Novgorod State University, 603950 Nizhniy Novgorod (Russian Federation); Csik, A. [Institute for Nuclear Research (INR), Hungarian Academy of Science, Bem tér 18/C, 4026 Debrecen (Hungary); Novikov, A.V. [Institute for Physics of Microstructures of the Russian Academy of Sciences (IPM RAS), 603950 Nizhniy Novgorod (Russian Federation); Lobachevski Nizhniy Novgorod State University, 603950 Nizhniy Novgorod (Russian Federation); Vad, K. [Institute for Nuclear Research (INR), Hungarian Academy of Science, Bem tér 18/C, 4026 Debrecen (Hungary); Yunin, P.A.; Yurasov, D.V. [Institute for Physics of Microstructures of the Russian Academy of Sciences (IPM RAS), 603950 Nizhniy Novgorod (Russian Federation); Lobachevski Nizhniy Novgorod State University, 603950 Nizhniy Novgorod (Russian Federation); Belykh, S.F. [MATI Russian State Technological University, Orshanskaya Str. 3, 121552 Moscow (Russian Federation); Gololobov, G.P.; Suvorov, D.V. [Ryazan State Radio Engineering University, Gagarin Str. 59/1, 390005 Ryazan (Russian Federation); Tolstogouzov, A., E-mail: a.tolstoguzov@fct.unl.pt [Ryazan State Radio Engineering University, Gagarin Str. 59/1, 390005 Ryazan (Russian Federation); Centre for Physics and Technological Research (CeFITec), Dept. de Física da Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2016-05-31

    Quantification of Ge in Si{sub 1–x}Ge{sub x} structures (0.092 ≤ x ≤ 0.78) was carried out by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and electron-gas secondary neutral mass spectrometry (SNMS). A good linear correlation (R{sup 2} > 0.9997) of the intensity ratios of secondary ions GeCs{sub 2}{sup +}/SiCs{sub 2}{sup +} and {sup 74}Ge{sup −}/{sup 30}Si{sup −} and post-ionized sputtered neutrals {sup 70}Ge{sup +}/{sup 28}Si{sup +} with Ge concentration was obtained. The calibration data were used for quantitative depth profiling of [10 × (12.3 nm Si{sub 0.63}Ge{sub 0.37}/34 nm Si)] structures on Si. Satisfactory compliance of the quantified Ge concentration in SiGe layers with the values obtained by high-resolution X-ray diffraction was revealed for both techniques. SIMS and SNMS experimental profiles were fitted using Hofmann's mixing-roughness-information depth (MRI) model. In the case of TOF-SIMS, the quality of the reconstruction was better than for SNMS since not only the progressing roughening, but also the crater effect and other processes unaccounted in the MRI simulation could have a significant impact on plasma sputter depth profiling.

  12. Evaluation of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry for identification of Candida parapsilosis, C. orthopsilosis and C. metapsilosis.

    Science.gov (United States)

    Quiles-Melero, I; García-Rodríguez, J; Gómez-López, A; Mingorance, J

    2012-01-01

    We have evaluated matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry for the rapid identification of Candida parapsilosis, C. orthopsilosis and C. metapsilosis. A total of 103 isolates, including reference strains and clinical isolates, were identified by pyrosequencing of the ITS1 region and then assay by MALDI-TOF mass spectrometry. Concordance between the two methods was 100%, showing that MALDI-TOF may be useful as a rapid and reliable method for discrimination of species within the C. parapsilosis group.

  13. Nano-localized desorption and time-of-flight mass analysis using solely optical enhancement in the proximity of a scanning tunneling microscope tip

    Science.gov (United States)

    Ding, Yu; Micheletto, Ruggero; Okazaki, Satoshi; Otsuka, Koji

    2003-04-01

    The combination of scanning tunneling microscopy (STM) with time-of-flight mass system (TOF-MS) adds new information to STM imaging. In this study, an STM system has been combined with laser excitation and was used for desorption and ionization of surface molecules, without the use of any other external stimulus. Desorbed ions from confined areas were accelerated and detected by a TOF chamber. We demonstrate in this paper that the technique proposed enables desorption of superficial structures within a small area of approximately 5 nm diameter and simultaneous mass spectroscopy of the desorbed atoms.

  14. Accurate Mass GC/LC-Quadrupole Time of Flight Mass Spectrometry Analysis of Fatty Acids and Triacylglycerols of Spicy Fruits from the Apiaceae Family

    Science.gov (United States)

    Nguyen, Thao; Aparicio, Mario; Saleh, Mahmoud A.

    2016-01-01

    The triacylglycerol (TAG) structure and the regio-stereospecific distribution of fatty acids (FA) of seed oils from most of the Apiaceae family are not well documented. The TAG structure ultimately determines the final physical properties of the oils and the position of FAs in the TAG molecule affects the digestion; absorption and metabolism; and physical and technological properties of TAGs. Fixed oils from the fruits of dill (Anethum graveolens), caraway (Carum carvi), cumin (Cuminum cyminum), coriander (Coriandrum sativum), anise (Pimpinella anisum), carrot (Daucus carota), celery (Apium graveolens), fennel (Foeniculum vulgare), and Khella (Ammi visnaga), all from the Apiaceae family, were extracted at room temperature in chloroform/methanol (2:1 v/v) using percolators. Crude lipids were fractionated by solid phase extraction to separate neutral triacylglycerols (TAGs) from other lipids components. Neutral TAGs were subjected to transesterification process to convert them to their corresponding fatty acids methyl esters (FAMES) using 1% boron trifluoride (BF3) in methanol. FAMES were analyzed by gas chromatography-quadrupole time of flight (GC-QTOF) mass spectrometry. Triglycerides were analyzed using high performance liquid chromatography-quadrupole time of flight (LC-QTOF) mass spectrometry. Petroselinic acid was the major fatty acid in all samples ranging from 57% of the total fatty acids in caraway up to 82% in fennel. All samples contained palmitic (16:0), palmitoleic (C16:1n-9), stearic (C18:0), petroselinic (C18:1n-12), linoleic (C18:2n-6), linolinic (18:3n-3), and arachidic (C20:0) acids. TAG were analyzed using LC-QTOF for accurate mass identification and mass spectrometry/mass spectrometry (MS/MS) techniques for regiospesific elucidation of the identified TAGs. Five major TAGs were detected in all samples but with different relative concentrations in all of the tested samples. Several other TAGs were detected as minor components and were present in

  15. Accurate Mass GC/LC-Quadrupole Time of Flight Mass Spectrometry Analysis of Fatty Acids and Triacylglycerols of Spicy Fruits from the Apiaceae Family.

    Science.gov (United States)

    Nguyen, Thao; Aparicio, Mario; Saleh, Mahmoud A

    2015-12-02

    The triacylglycerol (TAG) structure and the regio-stereospecific distribution of fatty acids (FA) of seed oils from most of the Apiaceae family are not well documented. The TAG structure ultimately determines the final physical properties of the oils and the position of FAs in the TAG molecule affects the digestion; absorption and metabolism; and physical and technological properties of TAGs. Fixed oils from the fruits of dill (Anethum graveolens), caraway (Carum carvi), cumin (Cuminum cyminum), coriander (Coriandrum sativum), anise (Pimpinella anisum), carrot (Daucus carota), celery (Apium graveolens), fennel (Foeniculum vulgare), and Khella (Ammi visnaga), all from the Apiaceae family, were extracted at room temperature in chloroform/methanol (2:1 v/v) using percolators. Crude lipids were fractionated by solid phase extraction to separate neutral triacylglycerols (TAGs) from other lipids components. Neutral TAGs were subjected to transesterification process to convert them to their corresponding fatty acids methyl esters (FAMES) using 1% boron trifluoride (BF₃) in methanol. FAMES were analyzed by gas chromatography-quadrupole time of flight (GC-QTOF) mass spectrometry. Triglycerides were analyzed using high performance liquid chromatography-quadrupole time of flight (LC-QTOF) mass spectrometry. Petroselinic acid was the major fatty acid in all samples ranging from 57% of the total fatty acids in caraway up to 82% in fennel. All samples contained palmitic (16:0), palmitoleic (C16:1n-9), stearic (C18:0), petroselinic (C18:1n-12), linoleic (C18:2n-6), linolinic (18:3n-3), and arachidic (C20:0) acids. TAG were analyzed using LC-QTOF for accurate mass identification and mass spectrometry/mass spectrometry (MS/MS) techniques for regiospesific elucidation of the identified TAGs. Five major TAGs were detected in all samples but with different relative concentrations in all of the tested samples. Several other TAGs were detected as minor components and were present in

  16. Accurate Mass GC/LC-Quadrupole Time of Flight Mass Spectrometry Analysis of Fatty Acids and Triacylglycerols of Spicy Fruits from the Apiaceae Family

    Directory of Open Access Journals (Sweden)

    Thao Nguyen

    2015-12-01

    Full Text Available The triacylglycerol (TAG structure and the regio-stereospecific distribution of fatty acids (FA of seed oils from most of the Apiaceae family are not well documented. The TAG structure ultimately determines the final physical properties of the oils and the position of FAs in the TAG molecule affects the digestion; absorption and metabolism; and physical and technological properties of TAGs. Fixed oils from the fruits of dill (Anethum graveolens, caraway (Carum carvi, cumin (Cuminum cyminum, coriander (Coriandrum sativum, anise (Pimpinella anisum, carrot (Daucus carota, celery (Apium graveolens, fennel (Foeniculum vulgare, and Khella (Ammi visnaga, all from the Apiaceae family, were extracted at room temperature in chloroform/methanol (2:1 v/v using percolators. Crude lipids were fractionated by solid phase extraction to separate neutral triacylglycerols (TAGs from other lipids components. Neutral TAGs were subjected to transesterification process to convert them to their corresponding fatty acids methyl esters (FAMES using 1% boron trifluoride (BF3 in methanol. FAMES were analyzed by gas chromatography-quadrupole time of flight (GC-QTOF mass spectrometry. Triglycerides were analyzed using high performance liquid chromatography-quadrupole time of flight (LC-QTOF mass spectrometry. Petroselinic acid was the major fatty acid in all samples ranging from 57% of the total fatty acids in caraway up to 82% in fennel. All samples contained palmitic (16:0, palmitoleic (C16:1n-9, stearic (C18:0, petroselinic (C18:1n-12, linoleic (C18:2n-6, linolinic (18:3n-3, and arachidic (C20:0 acids. TAG were analyzed using LC-QTOF for accurate mass identification and mass spectrometry/mass spectrometry (MS/MS techniques for regiospesific elucidation of the identified TAGs. Five major TAGs were detected in all samples but with different relative concentrations in all of the tested samples. Several other TAGs were detected as minor components and were present in some

  17. Influence of internal standard charge state on the accuracy of mass measurements in orthogonal acceleration time-of-flight mass spectrometers.

    Science.gov (United States)

    Charles, Laurence

    2008-01-01

    Accuracy of mass measurements performed in orthogonal acceleration time-of-flight (oa-TOF) mass spectrometers highly depends on the quality of the signal and the internal calibration. The use of two reference compounds which bracket the targeted unknown, give rise to ions with sufficient signal-to-noise ratio while avoiding detector saturation and produce signals of similar intensity as compared to the target is a common requirement which allow a 5 ppm accuracy on a routine basis. Ion charge state is demonstrated here to be an additional and particularly critical parameter. Using internal references of lower charge state than the target ion systematically yielded overestimated data. Errors measured for quadruply charged molecules were in the range 16-18 ppm when mass calibrants were singly charged ions while accuracy was below 5 ppm when references and target ions were in the same charge state. Magnitude of errors was found to increase with the difference in charge state. This phenomenon arises from the orthogonal acceleration of ions in the TOF analyzer, an interface implemented in all TOF mass spectrometers to accommodate continuous beam ionization sources.

  18. Advanced 360o FOV, wide energy range, non-HV, gated time of flight mass spectrometers for Small Satellites and Cubesats

    Science.gov (United States)

    Paschalidis, N.; Jones, S.; Rodriguez, M.; Sittler, E. C., Jr.; Chornay, D. J.; Uribe, P.; Cameron, T.; Nanan, G.

    2015-12-01

    The time of flight technique is widely used for composition analysis of space plasma instruments. The foil - MCP/CEM combination is commonly used for E x TOF mass analysis at the cost of energy threshold, scattering, and direct particle interaction which ultimately affect performance. An alternative method especially effective at low energies is gated time of flight where the start foil is replaced with electric gating. There are several advantages of electric gating, including elimination of heavy HVPS required for pre-reacceleration to overcome foil thresholds, non- destructive interaction with atomic and molecular ions before analysis, and electronic controllability including geometric factor adjustment for flux dynamic range, FOV optimization, electronic filtering of most abundant elements in favor of minor species, and other properties affecting directly the scientific and engineering performance of the instruments. In addition special secondary emission surfaces can be used for triple coincidence when needed. The combination of electric gating and special surfaces works in an extensive energy range from 0 to tens of KeV without the need of start foil/HVPS making thus the use attractive to small satellites and cubesats. Those characteristics will be elaborated in the context of a gated time of flight wide field of view and energy range ion spectrometer combined with a neutral mass spectrometer (WINMS) developed at GSFC. The instrument prototypes have mass resolution adequate to separate N, O, OH, OH2; also static from ram moving H allowing thus separation of outgassing from ambient gases. A first implementation INMS with a mass <600 grams and size <1.5U is the main payload of the EXOCUBE Cubesat mission launched in January 2015 and already produced flight data; a second upgraded implementation is on onboard the GSFC Dellingr 6U CubeSat scheduled for launch in late 2015; and ongoing developments are baselined for other satellite missions.

  19. Environmental forensics in groundwater coupling passive sampling and high resolution mass spectrometry for screening.

    Science.gov (United States)

    Soulier, Coralie; Coureau, Charlotte; Togola, Anne

    2016-09-01

    One of the difficulties encountered when monitoring groundwater quality is low and fluctuating concentration levels and complex mixtures of micropollutants, including emerging substances or transformation products. Combining passive sampling techniques with analysis by high resolution mass spectrometry (HRMS) should improve environmental metrology. Passive samplers accumulate compounds during exposure, which improves the detection of organic compounds and integrates pollution fluctuations. The Polar Organic Chemical Integrative Sampler (POCIS) were used in this study to sequester polar to semi-polar compounds. The methodology described here improves our knowledge of environmental pollution by highlighting and identifying pertinent compounds to be monitored in groundwater. The advantage of combining these two approaches is demonstrated on two different sites impacted by agricultural and/or urban pollution sources where groundwater was sampled for several months. Grab and passive sampling were done and analyzed by liquid chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer (LC-QTOF). Various data processing approaches were used (target, suspect and non-target screening). Target screening was based on research from compounds listed in a homemade database and suspect screening used a database compiled using literature data. The non-target screening was done using statistical tools such as principal components analysis (PCA) with direct connections between original chromatograms and ion intensity. Trend plots were used to highlight relevant compounds for their identification. The advantage of using POCIS to improve screening of polar organic compounds was demonstrated. Compounds undetected in water samples were detected with these tools. The subsequent data processing identified sentinel molecules, molecular clusters as compounds never revealed in these sampling sites, and molecular fingerprints. Samples were compared and multidimensional

  20. Extension of the two-dimensional mass channel cluster plot method to fast separations utilizing low thermal mass gas chromatography with time-of-flight mass spectrometry.

    Science.gov (United States)

    Fitz, Brian D; Synovec, Robert E

    2016-03-24

    Implementation of a data reduction and visualization method for use with high-speed gas chromatography and time-of-flight mass spectrometry (GC-TOFMS) is reported. The method, called the "2D m/z cluster method" facilitates analyte detection, deconvolution, and identification, by accurately measuring peak widths and retention times using a fast TOFMS sampling frequency (500 Hz). Characteristics and requirements for high speed GC are taken into consideration: fast separations with narrow peak widths and high peak capacity, rapid data collection rate, and effective peak deconvolution. Transitioning from standard GC (10-60+ minute separations) to fast GC (1-10 min separations) required consideration of how to properly analyze the data. This report validates use of the 2D m/z cluster method with newly developed GC technology that produces ultra-fast separations (∼1 min) with narrow analyte peak widths. Low thermal mass gas chromatography (LTM-GC) operated at a heating rate of 250 °C/min coupled to a LECO Pegasus III TOFMS analyzed a 115 component test mixture in 120 s with peak widths-at-base, wb (4σ), of 350 ms (average) to produce a separation with a high peak capacity, nc ∼ 340 (at unit resolution Rs = 1). The 2D m/z cluster method is shown to separate overlapped analytes to a limiting Rs ∼ 0.03, so the effective peak capacity was increased nearly 30-fold to nc ∼10,000 in the 120 s separation. The method, when coupled with LTM-GC-TOFMS, is demonstrated to provide unambiguous peak rank (i.e. the number of analytes per overlapped peak in the total ion current (TIC)), by visualizing locations of pure and chromatographically overlapped m/z. Hence, peak deconvolution and identification using MCR-ALS (multivariate curve resolution - alternating least squares) is demonstrated.

  1. Investigation of Tobacco Pyrolysis Gases and Puff-by-puff Resolved Cigarette Smoke by Single Photon Ionisation (SPI - Time-of-flight Mass Spectrometry (TOFMS

    Directory of Open Access Journals (Sweden)

    Adam T

    2014-12-01

    Full Text Available The work presented deals with the application of Single Photon Ionisation- Time-of-Flight Mass Spectrometry (SPI-TOFMS for the investigation of tobacco smoke. SPI-TOFMS is a modern analytical technique, which enables the simultaneous analysis of a large number of organic species in complex gas mixtures in real time. The paper is a summary of a PhD thesis (1 and seven research articles, which were recently published in various scientific journals (2-8. Consequently, more detailed information on particular aspects can be found in there.

  2. Two-dimensional and three-dimensional dynamic imaging of live biofilms in a microchannel by time-of-flight secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Xin; Marshall, Matthew J.; Xiong, Yijia; Ma, Xiang; Zhou, Yufan; Tucker, Abigail E.; Zhu, Zihua; Liu, Songqin; Yu, Xiao-Ying

    2015-05-01

    A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface) was employed for in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials in sequential layers resulted in live biofilm spatial chemical mapping. 2D images were reconstructed to report the first 3D images of hydrated biofilm elucidating spatial and chemical heterogeneity. 2D image principal component analysis (PCA) was conducted among biofilms at different locations in the microchannel. Our approach directly visualized spatial and chemical heterogeneity within the living biofilm by dynamic liquid ToF-SIMS.

  3. Two-dimensional and three-dimensional dynamic imaging of live biofilms in a microchannel by time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Hua, Xin; Marshall, Matthew J; Xiong, Yijia; Ma, Xiang; Zhou, Yufan; Tucker, Abigail E; Zhu, Zihua; Liu, Songqin; Yu, Xiao-Ying

    2015-05-01

    A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface), was employed for in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials in sequential layers resulted in live biofilm spatial chemical mapping. Two-dimensional (2D) images were reconstructed to report the first three-dimensional images of hydrated biofilm elucidating spatial and chemical heterogeneity. 2D image principal component analysis was conducted among biofilms at different locations in the microchannel. Our approach directly visualized spatial and chemical heterogeneity within the living biofilm by dynamic liquid ToF-SIMS.

  4. Real-time detection of individual secondary organic aerosol particle from photooxidation of toluene using aerosol time of flight mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenya; HAO Liqing; ZHOU Liuzhu; GUO Xiaoyong; ZHAO Wenwu; FANG Li; ZHANG Weijun

    2006-01-01

    Photooxidation of the aromatic hydrocarbon toluene and its subsequent reactions were carried out using UV-irradiation of toluene/CH3ONO/NO/air mixtures in a home-made smog chamber.The secondary organic aerosols could be formed after those oxidation products of semi-volatile or-ganic compounds were partitioned between gas phase and particle phase. The aerosol time of flight mass spectrometer (ATOFMS) was used to measure size and molecular composition of individual secondary organic aerosol particle. Size distribution and chemical composition of secondary organic aerosol were got in real time.

  5. Assessment of Reproducibility of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Bacterial and Yeast Identification.

    Science.gov (United States)

    Westblade, Lars F; Garner, Omai B; MacDonald, Karen; Bradford, Constance; Pincus, David H; Mochon, A Brian; Jennemann, Rebecca; Manji, Ryhana; Bythrow, Maureen; Lewinski, Michael A; Burnham, Carey-Ann D; Ginocchio, Christine C

    2015-07-01

    Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of clinical bacterial and yeast isolates. However, data describing the reproducibility of MALDI-TOF MS for microbial identification are scarce. In this study, we show that MALDI-TOF MS-based microbial identification is highly reproducible and can tolerate numerous variables, including differences in testing environments, instruments, operators, reagent lots, and sample positioning patterns. Finally, we reveal that samples of bacterial and yeast isolates prepared for MALDI-TOF MS identification can be repeatedly analyzed without compromising organism identification.

  6. Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of KPC-Producing Klebsiella pneumoniae.

    Science.gov (United States)

    Gaibani, Paolo; Galea, Anna; Fagioni, Marco; Ambretti, Simone; Sambri, Vittorio; Landini, Maria Paola

    2016-10-01

    We evaluated a real-time single-peak (11.109-Da) detection assay based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae Our results demonstrated that the 11.109-Da peak was detected in 88.2% of the KPC producers. Analysis of blaKPC-producing K. pneumoniae showed that the gene encoding the 11.109-Da protein was commonly (97.8%) associated with the Tn4401a isoform.

  7. Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of KPC-Producing Klebsiella pneumoniae

    Science.gov (United States)

    Galea, Anna; Fagioni, Marco; Ambretti, Simone; Sambri, Vittorio; Landini, Maria Paola

    2016-01-01

    We evaluated a real-time single-peak (11.109-Da) detection assay based on matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for the identification of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae. Our results demonstrated that the 11.109-Da peak was detected in 88.2% of the KPC producers. Analysis of blaKPC-producing K. pneumoniae showed that the gene encoding the 11.109-Da protein was commonly (97.8%) associated with the Tn4401a isoform. PMID:27413192

  8. Metabonomic Study of Biochemical Changes in Human Hair of Heroin Abusers by Liquid Chromatography Coupled with Ion Trap-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Xie, Pu; Wang, Tie-jie; Yin, Guo; Yan, Yan; Xiao, Li-he; Li, Qing; Bi, Kai-shun

    2016-01-01

    Hair analysis is with the advantage of non-invasive collection and long surveillance window. The present study employed a sensitive and reliable liquid chromatography coupled with ion trap-time of flight mass spectrometry method to study the metabonomic characters in the hair of 58 heroin abusers and 72 non-heroin abusers. Results indicated that certain endogenous metabolites, such as sorbitol and cortisol, were accelerated, and the level of arachidonic acid, glutathione, linoleic acid, and myristic acid was decreased in hair of heroin abusers. The metabonomic study is helpful for further understanding of heroin addiction and clinical diagnosis.

  9. Data acquisition techniques for exploiting the uniqueness of the time-of-flight mass spectrometer: Application to sampling pulsed gas systems

    Science.gov (United States)

    Lincoln, K. A.

    1980-01-01

    Mass spectra are produced in most mass spectrometers by sweeping some parameter within the instrument as the sampled gases flow into the ion source. It is evident that any fluctuation in the gas during the sweep (mass scan) of the instrument causes the output spectrum to be skewed in its mass peak intensities. The time of flight mass spectrometer (TOFMS) with its fast, repetitive mode of operation produces spectra without skewing or varying instrument parameters and because all ion species are ejected from the ion source simultaneously, the spectra are inherently not skewed despite rapidly changing gas pressure or composition in the source. Methods of exploiting this feature by utilizing fast digital data acquisition systems, such as transient recorders and signal averagers which are commercially available are described. Applications of this technique are presented including TOFMS sampling of vapors produced by both pulsed and continuous laser heating of materials.

  10. Characterization of goat colostrum oligosaccharides by nano-liquid chromatography on chip quadrupole time-of-flight mass spectrometry and hydrophilic interaction liquid chromatography-quadrupole mass spectrometry.

    Science.gov (United States)

    Martín-Ortiz, A; Salcedo, J; Barile, D; Bunyatratchata, A; Moreno, F J; Martin-García, I; Clemente, A; Sanz, M L; Ruiz-Matute, A I

    2016-01-08

    A detailed qualitative and quantitative characterization of goat colostrum oligosaccharides (GCO) has been carried out for the first time. Defatted and deproteinized colostrum samples, previously treated by size exclusion chromatography (SEC) to remove lactose, were analyzed by nanoflow liquid chromatography-quadrupole-time of flight mass spectrometry (Nano-LC-Chip-Q-TOF MS). Up to 78 oligosaccharides containing hexose, hexosamine, fucose, N-acetylneuraminic acid or N-glycolylneuraminic acid monomeric units were identified in the samples, some of them detected for the first time in goat colostra. As a second step, a hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-MS) methodology was developed for the separation and quantitation of the main GCO, both acidic and neutral carbohydrates. Among other experimental chromatographic conditions, mobile phase additives and column temperature were evaluated in terms of retention time, resolution, peak width and symmetry of target carbohydrates. Narrow peaks (wh: 0.2-0.6min) and good symmetry (As: 0.8-1.4) were obtained for GCO using an acetonitrile:water gradient with 0.1% ammonium hydroxide at 40°C. These conditions were selected to quantify the main oligosaccharides in goat colostrum samples. Values ranging from 140 to 315mgL(-1) for neutral oligosaccharides and from 83 to 251mgL(-1) for acidic oligosaccharides were found. The combination of both techniques resulted to be useful to achieve a comprehensive characterization of GCO.

  11. Characterization of metabolism of (+)-praeruptorin B and (+)-praeruptorin E in human and rat liver microsomes by liquid chromatography coupled with ion trap mass spectrometry and time-of-flight mass spectrometry.

    Science.gov (United States)

    Song, Yue-Lin; Yan, Ru; Jing, Wang-Hui; Zhao, Hai-Yu; Wang, Yi-Tao

    2011-03-30

    Peucedani Radix is a Chinese medicinal herb noted for its effects on treatments of respiratory and pulmonary disorders. As a part of a systematic pharmacokinetic evaluation of the herb in our laboratory, the present study investigated, for the first time, the metabolic profile of (+)-praeruptorin B (dPB) and (+)-praeruptorin E (dPE), two main bioactive constituents of Peucedani Radix in pooled liver microsomes of rats (RLMs) and humans (HLMs). dPE was eliminated faster than dPB in both species. The incubation of dPB with RLMs and HLMs resulted in eight (B1-B8) and nine (B1-B9) metabolites, respectively, while both RLMs and HLMs converted dPE into 13 metabolites (E1-13). Structures of all the metabolites were proposed through comparing their mass data obtained via tandem mass spectrometry on an MSD ion trap system (IT-MS/MS) coupled with high-resolution mass measurement by time-of-flight mass spectrometry (TOF-MS) with those of the respective parent compound. B1 and E1 were unambiguously identified as (-)-cis-khellactone. The formations of all the metabolites were NADPH-dependent. Oxidation and hydrolysis were demonstrated to be two predominant metabolic pathways of dPB and dPE. Oxidation initiated at either the C-3' or C-4' substituent, while hydrolysis only started from the C-3' substituent. Fragmentation of all metabolites followed similar pathways to those of the parent pyranocoumarins. The information on metabolic properties of dPB and dPE and the mass fragmentation profiles of their metabolites obtained in the present study will aid in characterization of metabolic profiles of other angular-type pyranocoumarins and further investigation of in vivo fates of these pyranocoumarins and the herb.

  12. Current use of high-resolution mass spectrometry in the environmental sciences

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, F.; Sancho, J.V.; Ibanez, M.; Portoles, T. [University Jaume I, Research Institute for Pesticides and Water, Castellon (Spain); Abad, E.; Mattioli, L. [IDAEA-CSIC, Laboratory of Dioxins, Department of Environmental Chemistry, Barcelona (Spain)

    2012-05-15

    During the last two decades, mass spectrometry (MS) has been increasingly used in the environmental sciences with the objective of investigating the presence of organic pollutants. MS has been widely coupled with chromatographic techniques, both gas chromatography (GC) and liquid chromatography (LC), because of their complementary nature when facing a broad range of organic pollutants of different polarity and volatility. A clear trend has been observed, from the very popular GC-MS with a single quadrupole mass analyser, to tandem mass spectrometry (MS-MS) and, more recently, high-resolution mass spectrometry (HRMS). For years GC has been coupled to HR magnetic sector instruments, mostly for dioxin analysis, although in the last ten years there has been growing interest in HRMS with time-of-flight (TOF) and Orbitrap mass analyzers, especially in LC-MS analysis. The increasing interest in the use of HRMS in the environmental sciences is because of its suitability for both targeted and untargeted analysis, owing to its sensitivity in full-scan acquisition mode and high mass accuracy. With the same instrument one can perform a variety of tasks: pre- and post-target analysis, retrospective analysis, discovery of metabolite and transformation products, and non-target analysis. All these functions are relevant to the environmental sciences, in which the analyst encounters thousands of different organic contaminants. Thus, wide-scope screening of environmental samples is one of the main applications of HRMS. This paper is a critical review of current use of HRMS in the environmental sciences. Needless to say, it is not the intention of the authors to summarise all contributions of HRMS in this field, as in classic descriptive reviews, but to give an overview of the main characteristics of HRMS, its strong potential in environmental mass spectrometry and the trends observed over the last few years. Most of the literature has been acquired since 2005, coinciding with the

  13. Simultaneous determination of six toxic alkaloids in human plasma and urine using capillary zone electrophoresis coupled to time-of-flight mass spectrometry.

    Science.gov (United States)

    Yu, Zhuhong; Wu, Zhongping; Gong, Feijun; Wong, Rong; Liang, Chen; Zhang, Yurong; Yu, Yunqiu

    2012-10-01

    A novel capillary zone electrophoresis separation coupled to electro spray ionization time-of-flight mass spectrometry method was developed for the simultaneous analysis of six toxic alkaloids: brucine, strychnine, atropine sulfate, anisodamine hydrobromide, scopolamine hydrobromide and anisodine hydrobromide in human plasma and urine. To obtain optimal sensitivity, a solid-phase extraction method using Oasis MCX cartridges (1 mL, 30 mg; Waters, USA) for the pretreatment of samples was used. All compounds were separated by capillary zone electrophoresis at 25 kV within 12 min in an uncoated fused-silica capillary of 75 μm id × 100 cm and were detected by time-of-flight mass spectrometry. This method was validated with regard to precision, accuracy, sensitivity, linear range, limit of detection (LOD), and limit of quantification (LOQ). In the plasma and urine samples, the linear calibration curves were obtained over the range of 0.50-100 ng/mL. The LOD and LOQ were 0.2-0.5 ng/mL and 0.5-1.0 ng/mL, respectively. The intra- and interday precision was better than 12% and 13%, respectively. Electrophoretic peaks could be identified by mass analysis.

  14. Isotopic Ratio Outlier Analysis of the S. cerevisiae Metabolome Using Accurate Mass Gas Chromatography/Time-of-Flight Mass Spectrometry: A New Method for Discovery.

    Science.gov (United States)

    Qiu, Yunping; Moir, Robyn; Willis, Ian; Beecher, Chris; Tsai, Yu-Hsuan; Garrett, Timothy J; Yost, Richard A; Kurland, Irwin J

    2016-03-01

    Isotopic ratio outlier analysis (IROA) is a (13)C metabolomics profiling method that eliminates sample to sample variance, discriminates against noise and artifacts, and improves identification of compounds, previously done with accurate mass liquid chromatography/mass spectrometry (LC/MS). This is the first report using IROA technology in combination with accurate mass gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS), here used to examine the S. cerevisiae metabolome. S. cerevisiae was grown in YNB media, containing randomized 95% (13)C, or 5%(13)C glucose as the single carbon source, in order that the isotopomer pattern of all metabolites would mirror the labeled glucose. When these IROA experiments are combined, the abundance of the heavy isotopologues in the 5%(13)C extracts, or light isotopologues in the 95%(13)C extracts, follows the binomial distribution, showing mirrored peak pairs for the molecular ion. The mass difference between the (12)C monoisotopic and the (13)C monoisotopic equals the number of carbons in the molecules. The IROA-GC/MS protocol developed, using both chemical and electron ionization, extends the information acquired from the isotopic peak patterns for formulas generation. The process that can be formulated as an algorithm, in which the number of carbons, as well as the number of methoximations and silylations are used as search constraints. In electron impact (EI/IROA) spectra, the artifactual peaks are identified and easily removed, which has the potential to generate "clean" EI libraries. The combination of chemical ionization (CI) IROA and EI/IROA affords a metabolite identification procedure that enables the identification of coeluting metabolites, and allowed us to characterize 126 metabolites in the current study.

  15. Accurate-mass databases for comprehensive screening of pesticide residues in food by fast liquid chromatography time-of-flight mass spectrometry.

    Science.gov (United States)

    Mezcua, Milagros; Malato, Octavio; García-Reyes, Juan F; Molina-Díaz, Antonio; Fernández-Alba, Amadeo R

    2009-02-01

    Because of the international trade of fruits and vegetables and the lack of harmonized regulations on the use of pesticides worldwide, the development of comprehensive screening methods for analyzing hundreds of pesticides and other banned chemicals is very convenient. This work reports the development and evaluation of a rapid automated screening method for determining pesticide residues in food using liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) based on the use of an accurate-mass database. The database created includes data not only on the accurate masses of the target ions but also the characteristic in-source fragment ions (over 400 fragments included) and retention time data. This customized database was associated to commercially available software which extracted all the potential compounds of interest from the LC-TOFMS raw data of each sample and matched them against the database to search for targeted compounds in the sample. This automatic screening method requires a careful optimization of the accurate-mass window and retention time tolerances, which play a determinant role on the selectivity, accuracy, and throughput of the whole procedure. Values of 10 mDa for preliminary screening and 1 mDa/5 ppm for confirmation along with a +/-0.15 min retention time window were found to be optimum for the compounds and samples tested. The optimized methods enable the automated screening of ca. 300 compounds in less than 20 min including the LC-MS run and data processing. The proposed method was applied to 60 real samples, and the results of the positive findings compared well with those obtained using a liquid chromatography tandem mass spectrometry (LC-MS/MS) method (triple quadrupole). The rates obtained on the identification of compounds in spiked and real samples in an automated fashion at different concentration levels were over 95% of the compounds, thus revealing as a convenient tool for the large-scale screening of

  16. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for rapid identification of fungal rhinosinusitis pathogens.

    Science.gov (United States)

    Huang, Yanfei; Wang, Jinglin; Zhang, Mingxin; Zhu, Min; Wang, Mei; Sun, Yufeng; Gu, Haitong; Cao, Jingjing; Li, Xue; Zhang, Shaoya; Lu, Xinxin

    2017-03-01

    Filamentous fungi are among the most important pathogens, causing fungal rhinosinusitis (FRS). Current laboratory diagnosis of FRS pathogens mainly relies on phenotypic identification by culture and microscopic examination, which is time consuming and expertise dependent. Although matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS has been employed to identify various fungi, its efficacy in the identification of FRS fungi is less clear. A total of 153 FRS isolates obtained from patients were analysed at the Clinical Laboratory at the Beijing Tongren Hospital affiliated to the Capital Medical University, between January 2014 and December 2015. They were identified by traditional phenotypic methods and Bruker MALDI-TOF MS (Bruker, Biotyper version 3.1), respectively. Discrepancies between the two methods were further validated by sequencing. Among the 153 isolates, 151 had correct species identification using MALDI-TOF MS (Bruker, Biot 3.1, score ≥2.0 or 2.3). MALDI-TOF MS enabled identification of some very closely related species that were indistinguishable by conventional phenotypic methods, including 1/10 Aspergillus versicolor, 3/20 Aspergillus flavus, 2/30 Aspergillus fumigatus and 1/20 Aspergillus terreus, which were misidentified by conventional phenotypic methods as Aspergillus nidulans, Aspergillus oryzae, Aspergillus japonicus and Aspergillus nidulans, respectively. In addition, 2/2 Rhizopus oryzae and 1/1 Rhizopus stolonifer that were identified only to the genus level by the phenotypic method were correctly identified by MALDI-TOF MS. MALDI-TOF MS is a rapid and accurate technique, and could replace the conventional phenotypic method for routine identification of FRS fungi in clinical microbiology laboratories.

  17. Identification of metabolites of Radix Paeoniae Alba extract in rat bile, plasma and urine by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Zheng-Wei Chen; Ling Tong; Shu-Ming Li; Dong-Xiang Li; Ying Zhang; Shui-Ping Zhou; Yong-Hong Zhu; He Sun

    2014-01-01

    Ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was developed to identify the absorbed parent components and metabolites in rat bile, plasma and urine after oral administration of Radix Paeoniae Alba extract (RPAE). A total of 65 compounds were detected in rat bile, plasma and urine samples, including 11 parent compounds and 54 metabolites. The results indicated that glucuronidation, hydroxylation and methylation were the major metabolic pathways of the components of RPAE. Furthermore, the results of this work demonstrated that UPLC-Q-TOF/MS combined with MetaboLynx™ software and mass defect filtering (MDF) could provide unique high throughput capabilities for drug metabolism study, with excellent MS mass accuracy and enhanced MSE data acquisition. With the MSE technique, both precursor and fragment mass spectra can be simultaneously acquired by alternating between high and low collision energy during a single chromatographic run.

  18. Search for efficient laser resonance ionization schemes of tantalum using a newly developed time-of-flight mass-spectrometer in KISS

    Science.gov (United States)

    Mukai, M.; Hirayama, Y.; Ishiyama, H.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Watanabe, Y. X.; Kimura, S.; Ozawa, A.; Jeong, S. C.; Sonoda, T.

    2016-06-01

    The technique of laser resonance ionization is employed for an element-selective ionization of multi-nucleon transfer reaction products which are stopped and neutralized in a gas cell filled with argon gas at 50 kPa. We have been searching for efficient laser ionization schemes for refractory elements of Z = 73-78 using a time-of-flight mass-spectrometer (TOF-MS) chamber. To evaluate the isotope shift and ionization efficiency for each candidate of the ionization scheme, isotope separation using the TOF-MS was devised. The TOF-MS was designed to separate the isotopes using two-stage linear acceleration with a mass resolving power M / ΔM of >350. A mass resolving power of 250 was experimentally confirmed by measuring the TOF of laser-ionized tantalum (Z = 73) ions with mass number 181. We searched for a laser resonance ionization scheme of tantalum using the TOF-MS.

  19. Compact Two-step Laser Time-of-Flight Mass Spectrometer for in Situ Analyses of Aromatic Organics on Planetary Missions

    Science.gov (United States)

    Getty, Stephanie; Brickerhoff, William; Cornish, Timothy; Ecelberger, Scott; Floyd, Melissa

    2012-01-01

    RATIONALE A miniature time-of-flight mass spectrometer has been adapted to demonstrate two-step laser desorption-ionization (LOI) in a compact instrument package for enhanced organics detection. Two-step LDI decouples the desorption and ionization processes, relative to traditional laser ionization-desorption, in order to produce low-fragmentation conditions for complex organic analytes. Tuning UV ionization laser energy allowed control ofthe degree of fragmentation, which may enable better identification of constituent species. METHODS A reflectron time-of-flight mass spectrometer prototype measuring 20 cm in length was adapted to a two-laser configuration, with IR (1064 nm) desorption followed by UV (266 nm) postionization. A relatively low ion extraction voltage of 5 kV was applied at the sample inlet. Instrument capabilities and performance were demonstrated with analysis of a model polycyclic aromatic hydrocarbon, representing a class of compounds important to the fields of Earth and planetary science. RESULTS L2MS analysis of a model PAH standard, pyrene, has been demonstrated, including parent mass identification and the onset o(tunable fragmentation as a function of ionizing laser energy. Mass resolution m/llm = 380 at full width at half-maximum was achieved which is notable for gas-phase ionization of desorbed neutrals in a highly-compact mass analyzer. CONCLUSIONS Achieving two-step laser mass spectrometry (L2MS) in a highly-miniature instrument enables a powerful approach to the detection and characterization of aromatic organics in remote terrestrial and planetary applications. Tunable detection of parent and fragment ions with high mass resolution, diagnostic of molecular structure, is possible on such a compact L2MS instrument. Selectivity of L2MS against low-mass inorganic salt interferences is a key advantage when working with unprocessed, natural samples, and a mechanism for the observed selectivity is presented.

  20. Identification of Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Time-of-Flight Mass Spectrometry (TOFMS).

    Science.gov (United States)

    Strynar, Mark; Dagnino, Sonia; McMahen, Rebecca; Liang, Shuang; Lindstrom, Andrew; Andersen, Erik; McMillan, Larry; Thurman, Michael; Ferrer, Imma; Ball, Carol

    2015-10-06

    Recent scientific scrutiny and concerns over exposure, toxicity, and risk have led to international regulatory efforts resulting in the reduction or elimination of certain perfluorinated compounds from various products and waste streams. Some manufacturers have started producing shorter chain per- and polyfluorinated compounds to try to reduce the potential for bioaccumulation in humans and wildlife. Some of these new compounds contain central ether oxygens or other minor modifications of traditional perfluorinated structures. At present, there has been very limited information published on these "replacement chemistries" in the peer-reviewed literature. In this study we used a time-of-flight mass spectrometry detector (LC-ESI-TOFMS) to identify fluorinated compounds in natural waters collected from locations with historical perfluorinated compound contamination. Our workflow for discovery of chemicals included sequential sampling of surface water for identification of potential sources, nontargeted TOFMS analysis, molecular feature extraction (MFE) of samples, and evaluation of features unique to the sample with source inputs. Specifically, compounds were tentatively identified by (1) accurate mass determination of parent and/or related adducts and fragments from in-source collision-induced dissociation (CID), (2) in-depth evaluation of in-source adducts formed during analysis, and (3) confirmation with authentic standards when available. We observed groups of compounds in homologous series that differed by multiples of CF2 (m/z 49.9968) or CF2O (m/z 65.9917). Compounds in each series were chromatographically separated and had comparable fragments and adducts produced during analysis. We detected 12 novel perfluoroalkyl ether carboxylic and sulfonic acids in surface water in North Carolina, USA using this approach. A key piece of evidence was the discovery of accurate mass in-source n-mer formation (H(+) and Na(+)) differing by m/z 21.9819, corresponding to the

  1. Normal phase liquid chromatography coupled to quadrupole time of flight atmospheric pressure chemical ionization mass spectrometry for separation, detection and mass spectrometric profiling of neutral sphingolipids and cholesterol.

    Science.gov (United States)

    Farwanah, Hany; Wirtz, Jennifer; Kolter, Thomas; Raith, Klaus; Neubert, Reinhard H H; Sandhoff, Konrad

    2009-10-01

    Many lipidomic approaches focus on investigating aspects of sphingolipid metabolism. Special emphasis is put on neutral sphingolipids and cholesterol and their interaction. Such an interest is attributed to the fact that those lipids are altered in a series of serious disorders including various sphingolipidoses. High performance thin-layer chromatography (HPTLC) has become a widely used technique for lipid analysis. However, mass spectrometric profiling is irreplaceable for gaining an overview about the various molecular species within a lipid class. In this work we have developed a sensitive method based on a gradient normal phase high performance liquid chromatography (HPLC) coupled to quadrupole time of flight (QTOF) atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in positive mode, which for the first time enables separation, on-line detection, and mass spectrometric profiling of multiple neutral sphingolipids including ceramide, glucosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, sphingomyelin as well as cholesterol within less than 15min. An important advantage of the presented HPLC/APCI-MS approach is that the separation pattern emulates the one obtained by an optimized HPTLC method with a multiple stage development. Thus, the lipid classes previously separated and quantified by HPTLC can be easily screened regarding their mass spectrometric profiles by HPLC/APCI-MS. In addition, the selected ionization conditions enable in-source fragmentation providing useful structural information. The methods (HPLC/APCI-MS and the optimized HPTLC) were applied for the analysis of the mentioned lipids in human fibroblasts. This approach is aimed basically at investigators who perform studies based on genetic modifications or treatment with pharmacological agents leading to changes in the biochemical pathways of neutral sphingolipids and cholesterol. In addition, it can be of interest for research on disorders related to

  2. ARTICLES: Influence Factors on Particle Growth for On-line Aerosol Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

    Science.gov (United States)

    Xia, Wei-wei; Ti, Ru-fang; Zhang, Zi-Iiang; Zheng, Hai-yang; Fang, Li

    2010-06-01

    An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the condenser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of biological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.

  3. Novel experimental setup for time-of-flight mass spectrometry ion detection in collisions of anionic species with neutral gas-phase molecular targets.

    Science.gov (United States)

    Oller, J C; Ellis-Gibbings, L; da Silva, F Ferreira; Limão-Vieira, P; García, G

    We report a novel experimental setup for studying collision induced products resulting from the interaction of anionic beams with a neutral gas-phase molecular target. The precursor projectile was admitted into vacuum through a commercial pulsed valve, with the anionic beam produced in a hollow cathode discharge-induced plasma, and guided to the interaction region by a set of deflecting plates where it was made to interact with the target beam. Depending on the collision energy regime, negative and positive species can be formed in the collision region and ions were time-of-flight (TOF) mass-analysed. Here, we present data on O2 precursor projectile, where we show clear evidence of O(-) and O2(-) formation from the hollow cathode source as well as preliminary results on the interaction of these anions with nitromethane, CH3NO2. The negative ions formed in such collisions were analysed using time-of-flight mass spectrometry. The five most dominant product anions were assigned to H(-), O(-), NO(-), CNO(-) and CH3NO2(-).

  4. Gas Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF-MS)-Based Metabolomics for Comparison of Caffeinated and Decaffeinated Coffee and Its Implications for Alzheimer's Disease: e104621

    National Research Council Canada - National Science Library

    Kai Lun Chang; Paul C Ho

    2014-01-01

    ... to the observed therapeutic benefits. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolomics approach was employed to characterize the metabolic differences between caffeinated and decaffeinated coffee...

  5. [Characterization of aromatic hydrocarbons in heavy gas oil using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry].

    Science.gov (United States)

    Guo, Kun; Zhou, Jian; Liu, Zelong

    2012-02-01

    An analytical method for separating and identifying the aromatic hydrocarbons in heavy gas oil using comprehensive two-dimensional gas chromatography (GC x GC) coupled to time-of-flight mass spectrometry (TOF MS) was established. The two-dimensional distribution by ring number of the aromatic hydrocarbons was obtained. Besides phenanthrene and methyl-phenanthrene, many other polycyclic aromatic hydrocarbons (PAHs) such as pyrene and benzo [a] anthracene were identified by using the retention times, standard mass spectra or literature reports. The method was successfully applied to the hydrotreating process of heavy gas oil and the hydrotreated products of phenanthrene, pyrene were identified. This method provided technical support for the characterization of aromatic hydrocarbons in heavy gas oil and the investigation of hydrogenation mechanism of polycyclic aromatic hydrocarbons. Compared with the conventional method, gas chromatography coupled to mass spectrometry (GC-MS), the GC x GC-TOF MS method illustrated the obvious advantages for heavy gas oil analysis.

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

    Science.gov (United States)

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

    2012-11-15

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

  7. Screening and quantitation of multiclass drugs of abuse and pharmaceuticals in hair by fast liquid chromatography electrospray time-of-flight mass spectrometry.

    Science.gov (United States)

    Domínguez-Romero, Juan C; García-Reyes, Juan F; Molina-Díaz, Antonio

    2011-07-15

    In this work, an automated screening method for the simultaneous identification and quantitation of 30 representative multiclass drugs (including opiates, cocaine and its main metabolite, cannabinoids, amphetamines and other stimulants in hair samples) has been developed using fast liquid-chromatography time-of-flight mass spectrometry (LC-TOFMS). The identification and quantitation of the drugs were carried out by liquid chromatography using a C(18) column (4.6×50 mm) with 1.8 μm particle size. Accurate mass measurements of ions of interest (typically [M+H](+)) by electrospray time-of-flight mass spectrometry in the positive ionization mode were used for unambiguous confirmation of the targeted species. Three sample preparation methodologies were evaluated: (a) direct methanolic extraction by sonication, (b) acidic extraction, and (c) alkaline digestion. Direct methanolic extraction showed better recoveries and cleaner extracts. The limits of detection obtained in hair matrix were as low as 5 pg mg(-1) for cocaine and cannabidiol, ranging from 5 to 75 pg mg(-1) for the studied species while the LOQ ranged from 15 to 250 pg mg(-1). The method has been applied to six hair samples from drug consumer volunteers, where the presence of at least one drug was confirmed by accurate mass measurements within 2 ppm (mass error) in most cases. The present study demonstrates the usefulness of LC-TOFMS for both screening and quantitation purposes in drug testing in hair. In addition, the possibility of non-target or a posteriori data analysis of samples or the extension of the procedure for testing for additional compounds offers interesting features for forensic analysis.

  8. Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, Vincenzo

    2016-01-01

    The use of liquid chromatography high-resolution mass spectrometry (LC-HRMS) and direct analysis real-time high-resolution mass spectrometry (DART-HRMS) defines a new scenario in the analysis of thermal-induced toxicants, such as acrylamide. Several factors contribute to the definition of the

  9. Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, Vincenzo

    2016-01-01

    The use of liquid chromatography high-resolution mass spectrometry (LC-HRMS) and direct analysis real-time high-resolution mass spectrometry (DART-HRMS) defines a new scenario in the analysis of thermal-induced toxicants, such as acrylamide. Several factors contribute to the definition of the com

  10. Characterization of ornidazole metabolites in human bile after intraveneous doses by ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    Jiangbo Du

    2012-04-01

    Full Text Available Ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS was used to characterize ornidazole metabolites in human bile after intravenous doses. A liquid chromatography tandem mass spectrometry (LC–MS/MS assay was developed for the determination of the bile level of ornidazole. Bile samples, collected from four patients with T-tube drainage after biliary tract surgery, were prepared by protein precipitation with acetonitrile before analysis. A total of 12 metabolites, including 10 novel metabolites, were detected and characterized. The metabolites of ornidazole in human bile were the products of hydrochloride (HCl elimination, oxidative dechlorination, hydroxylation, sulfation, diastereoisomeric glucuronation, and substitution of NO2 or Cl atom by cysteine or N-acetylcysteine, and oxidative dechlorination followed by further carboxylation. The bile levels of ornidazole at 12 h after multiple intravenous infusions were well above its minimal inhibitory concentration for common strains of anaerobic bacteria.

  11. A rapid method for chemical fingerprint analysis of Pan Panax notoginseng powders by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Liu, Peng; Yu, He-Shuil; Zhang, Li-Juan; Song, Xin-Bo; Kang, Li-Ping; Liu, Jing-Yuan; Zhang, Jie; Cao, Man; Yu, Kate; Kang, Ting-Guo; Ma, Bai-Ping

    2015-06-01

    A method coupling ultra-performance liquid chromatography (UPLC) with quadrupole time-of-flight mass spectrometer (Qtof MS) using the electrospray ionization (ESI) source was developed for the identification of the major saponins from Panax notoginseng powder (PNP). Ten different PNP samples were analyzed and evaluated for their quality by similarity evaluation and principle component analysis (PCA). Based on the accurate mass, summarized characteristic fragmentation behaviors, retention times of different types of saponins, related botanical biogenesis, and reported chromatographic behavior of saponins, fifty-one common peaks were effectively separated and identified, including 28 protopanaxadiol saponins and 18 protopanaxatriol saponins. Simultaneously, 15 significant discrepancy compounds were identified from the disqualified PNP samples. The established UPLC/Qtof MS fingerprint method was successfully applied for profiling and identifying the major saponins of PNP, providing a fast quality evaluation tool for distinguishing the authentic PNP and the adulterated products.

  12. Chemical and biological differentiation of three human breast cancer cell types using time-of-flight secondary ion mass spectrometry (TOF-SIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Kulp, K S; Berman, E F; Knize, M G; Shattuck, D L; Nelson, E J; Wu, L; Montgomery, J L; Felton, J S; Wu, K J

    2006-01-09

    We use Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) to image and classify individual cells based on their characteristic mass spectra. Using statistical data reduction on the large data sets generated during TOF-SIMS analysis, similar biological materials can be differentiated based on a combination of small changes in protein expression, metabolic activity and cell structure. We apply this powerful technique to image and differentiate three carcinoma-derived human breast cancer cell lines (MCF-7, T47D and MDA-MB-231). In homogenized cells, we show the ability to differentiate the cell types as well as cellular compartments (cytosol, nuclear and membrane). These studies illustrate the capacity of TOF-SIMS to characterize individual cells by chemical composition, which could ultimately be applied to detect and identify single aberrant cells within a normal cell population. Ultimately, we anticipate characterizing rare chemical changes that may provide clues to single cell progression within carcinogenic and metastatic pathways.

  13. Characterization of monoclonal antibodies by a fast and easy liquid chromatography-mass spectrometry time-of-flight analysis on culture supernatant.

    Science.gov (United States)

    Henninot, Antoine; Terrier, Aurelie; Charton, Julie; Urbain, Rémi; Fontayne, Alexandre; Deprez, Benoit; Beghyn, Terence

    2015-12-15

    Rapid and efficient structural analysis is key to the development of new monoclonal antibodies. We have developed a fast and easy process to obtain mass spectrometry profiles of antibodies from culture supernatant. Treatment of the supernatant with IdeS generates three fragments of 25 kDa that can be analyzed by liquid chromatography-mass spectrometry time-of-flight (LC-MS TOF) in one run: LC, Fd, and Fc/2. This process gives rapid access to isoform and glycoform profiles. To specifically measure the fucosylation yield, we included a one-pot treatment with EndoS that removes the distal glycan heterogeneity. Our process was successfully compared with high-performance capillary electrophoresis with laser-induced fluorescence detection (HPCE-LIF), currently considered as the "gold standard" method. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Studies on extracting solutions of endohedral rare-earth metallofullerenes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    孙大勇; 刘志强; 刘子阳; 郭兴华; 徐文国; 刘淑莹

    1997-01-01

    Thirteen extracting solutions of rare-earth metallofullerenes containing La,Ce,Pr,Nd Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm and Yb respectively have been investigated by means of matrix-assisted laser desorpuon/ ionization time-of-flight mass spectrometry.The influences of the positive-ion/negative-ion mode,laser intensity,ma trix and mass discrimination to the analytical results are studied,based on which the optimal analytical conditions have been determined.The results show that the extracting solutions contain large quantities of rare-earth metallofullerenes besides empty fullerenes.On the basis of comparing their relative intensities,the different structure stabilities and solubilities of metallofullerenes with different rare-earth metals encapsulated into the fullerene cages,as well as some possible reasons to those differences,are discussed.

  15. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as a tool for fast identification of protein binders in color layers of paintings.

    Science.gov (United States)

    Hynek, Radovan; Kuckova, Stepanka; Hradilova, Janka; Kodicek, Milan

    2004-01-01

    Identification of materials in color layers of paintings is necessary for correct decisions concerning restoration procedures as well as proving the authenticity of the painting. The proteins are usually important components of the painting layers. In this paper it has been demonstrated that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) can be used for fast and reliable identification of proteins in color layers even in old, highly aged matrices. The digestion can be easily performed directly on silica wafers which are routinely used for infrared analysis. The amount of material necessary for such an analysis is extremely small. Peptide mass mapping using digestion with trypsin followed by MALDI-TOFMS and identification of the protein was successfully used for determination of the binder from a painting of the 19th century.

  16. Direct analysis of pharmaceutical drug formulations using ion mobility spectrometry/quadrupole-time-of-flight mass spectrometry combined with desorption electrospray ionization.

    Science.gov (United States)

    Weston, Daniel J; Bateman, Robert; Wilson, Ian D; Wood, Tim R; Creaser, Colin S

    2005-12-01

    A novel approach to the rapid analysis of pharmaceutical drug formulations using hyphenated ion mobility spectrometry (IMS) and time-of-flight mass spectrometry (ToF-MS) that requires no sample pretreatment or chromatographic separation is described. A modified quadrupole time-of-flight mass spectrometer containing an ion mobility drift cell was used for gas-phase electrophoretic separation of ions prior to ToF-MS detection. The generation of sample ions directly from tablets and cream formulations was effected by desorption electrospray ionization (DESI) using a modified electrospray ion source. The analysis of a range of over-the-counter and prescription tablet formulations is described, including histamine H2 receptor antagonist (ranitidine), analgesic (paracetamol), opiate (codeine), and aromatase inhibitor anticancer (anastrozole) drugs. The successful determination of active drugs from soft formulations, such as an antiseptic cream (chlorhexidine) and a nicotine-containing skin patch, is also presented. Limits of detection for the active drugs using the DESI/IMS/ToF-MS method fell within the high-picomole to nanomole range. In all cases, the use of ion mobility drift tube separation showed increased selectivity for active drug responses (present as low as 0.14% w/w) over excipient responses such as poly(ethylene glycol). Tandem mass spectrometric analysis of precursor ions separated by IMS allowed positive confirmation of active drugs with little loss of ion mobility efficiency. The ability to analyze hard or soft pharmaceutical formulations directly by DESI combined with ion mobility spectrometry/mass spectrometry in approximately 2 min demonstrates the potential applicability of this novel method to pharmaceutical screening of low-molecular-weight drug formulations with high selectivity over the formulation vehicle.

  17. The performance and the characterization of laser ablation aerosol particle time-of-flight mass spectrometry (LAAP-ToF-MS)

    Science.gov (United States)

    Gemayel, Rachel; Hellebust, Stig; Temime-Roussel, Brice; Hayeck, Nathalie; Van Elteren, Johannes T.; Wortham, Henri; Gligorovski, Sasho

    2016-05-01

    Hyphenated laser ablation-mass spectrometry instruments have been recognized as useful analytical tools for the detection and chemical characterization of aerosol particles. Here we describe the performances of a laser ablation aerosol particle time-of-flight mass spectrometer (LAAP-ToF-MS) which was designed for aerodynamic particle sizing using two 405 nm scattering lasers and characterization of the chemical composition of single aerosol particle via ablation/ionization by a 193 nm excimer laser and detection in a bipolar time-of-flight mass spectrometer with a mass resolving power of m/Δm > 600.We describe a laboratory based optimization strategy for the development of an analytical methodology for characterization of atmospheric particles using the LAAP-ToF-MS instrument in combination with a particle generator, a differential mobility analyzer and an optical particle counter. We investigated the influence of particle number concentration, particle size and particle composition on the detection efficiency. The detection efficiency is a product of the scattering efficiency of the laser diodes and the ionization efficiency or hit rate of the excimer laser. The scattering efficiency was found to vary between 0.6 and 1.9 % with an average of 1.1 %; the relative standard deviation (RSD) was 17.0 %. The hit rate exhibited good repeatability with an average value of 63 % and an RSD of 18 %. In addition to laboratory tests, the LAAP-ToF-MS was used to sample ambient air during a period of 6 days at the campus of Aix-Marseille University, situated in the city center of Marseille, France. The optimized LAAP-ToF-MS methodology enables high temporal resolution measurements of the chemical composition of ambient particles, provides new insights into environmental science, and a new investigative tool for atmospheric chemistry and physics, aerosol science and health impact studies.

  18. A novel sample preparation method of matrix-assisted laser desorption/ionization time of flight mass spectrometry for polystyrene

    Institute of Scientific and Technical Information of China (English)

    Shu Zhang; Zhen Wen Zhao; Lei Xiong; Bin Xin; Wei Hua Hu; Shao Xiang Xiong

    2007-01-01

    A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported.Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved.The mechanism was also analyzed.

  19. Laser Photoionization Time-of-Flight Mass Spectrometry of Nitrated Polycyclic Aromatic Hydrocarbons and Nitrated Heterocyclic Compounds

    Science.gov (United States)

    1993-01-01

    Mass., 1986, Ch 13. 7. McQuarrie , D. A. Statistical Mechanics, Harper & Row, New York, 1976, App F. 8. Andrews, D. L. Lasers in Chemistry , Springer...Air Force Academy) 1985 THESIS Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Chemistry in the OFFICE...Application to Mass Spectrometry .......................... 32 3.3 Quantum Theory of M PI ................................. 33 ii 3.3.1 Time-Dependent

  20. Mass cytometry: technique for real time single cell multitarget immunoassay based on inductively coupled plasma time-of-flight mass spectrometry.

    Science.gov (United States)

    Bandura, Dmitry R; Baranov, Vladimir I; Ornatsky, Olga I; Antonov, Alexei; Kinach, Robert; Lou, Xudong; Pavlov, Serguei; Vorobiev, Sergey; Dick, John E; Tanner, Scott D

    2009-08-15

    A novel instrument for real time analysis of individual biological cells or other microparticles is described. The instrument is based on inductively coupled plasma time-of-flight mass spectrometry and comprises a three-aperture plasma-vacuum interface, a dc quadrupole turning optics for decoupling ions from neutral components, an rf quadrupole ion guide discriminating against low-mass dominant plasma ions, a point-to-parallel focusing dc quadrupole doublet, an orthogonal acceleration reflectron analyzer, a discrete dynode fast ion detector, and an 8-bit 1 GHz digitizer. A high spectrum generation frequency of 76.8 kHz provides capability for collecting multiple spectra from each particle-induced transient ion cloud, typically of 200-300 micros duration. It is shown that the transients can be resolved and characterized individually at a peak frequency of 1100 particles per second. Design considerations and optimization data are presented. The figures of merit of the instrument are measured under standard inductively coupled plasma (ICP) operating conditions ( 900 for m/z = 159, the sensitivity with a standard sample introduction system of >1.4 x 10(8) ion counts per second per mg L(-1) of Tb and an abundance sensitivity of (6 x 10(-4))-(1.4 x 10(-3)) (trailing and leading masses, respectively) are shown. The mass range (m/z = 125-215) and abundance sensitivity are sufficient for elemental immunoassay with up to 60 distinct available elemental tags. When 500) can be used, which provides >2.4 x 10(8) cps per mg L(-1) of Tb, at (1.5 x 10(-3))-(5.0 x 10(-3)) abundance sensitivity. The real-time simultaneous detection of multiple isotopes from individual 1.8 microm polystyrene beads labeled with lanthanides is shown. A real time single cell 20 antigen expression assay of model cell lines and leukemia patient samples immuno-labeled with lanthanide-tagged antibodies is presented.

  1. Fast analysis of volatile organic compounds and disinfection by-products in drinking water using solid-phase microextraction-gas chromatography/time-of-flight mass spectrometry.

    Science.gov (United States)

    Niri, Vadoud H; Bragg, Leslie; Pawliszyn, Janusz

    2008-08-08

    A fast method was developed for the extraction and analysis of volatile organic compounds, including disinfection by-products (DBPs), with headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS) techniques. A GC/time-of-flight (TOF)-MS instrument, which had fast acquisition rates and powerful deconvolution software, was used. Under optimum conditions total runtime was 45s. Volatile organic compounds (VOCs), including purgeable A and B compounds (listed in US Environmental Protection Agency method 624), were identified in standard water samples. Extraction times were 1min for more volatile compounds and 2min for less volatile compounds. The method was applied to the analysis of water samples treated under different disinfection processes and the results were compared with those from a liquid-liquid extraction method.

  2. 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.

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

    Science.gov (United States)

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

    2014-05-01

    The mutualisation of analytical platforms might be used to address rising healthcare costs. Our study aimed to evaluate the feasibility of networking a unique matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) system for common use in several university hospitals in Brussels, Belgium. During a one-month period, 1,055 successive bacterial isolates from the Brugmann University Hospital were identified on-site using conventional techniques; these same isolates were also identified using a MALDI-TOF MS system at the Porte de Hal Laboratory by sending target plates and identification projects via transportation and the INFECTIO_MALDI software (Infopartner, Nancy, France), respectively. The occurrence of transmission problems (helpdesk to manage potential connectivity problems.

  4. Comprehensive metabolite profiling of Plantaginis Semen using ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique.

    Science.gov (United States)

    Wang, Dandan; Qi, Meng; Yang, Qiming; Tong, Renchao; Wang, Rui; Bligh, S W Annie; Yang, Li; Wang, Zhengtao

    2016-05-01

    Plantaginis Semen is commonly used in traditional medicine to treat edema, hypertension, and diabetes. The commercially available Plantaginis Semen in China mainly comes from three species. To clarify the chemical composition and distinct different species of Plantaginis Semen, we established a metabolite profiling method based on ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique. A total of 108 compounds, including phenylethanoid glycosides, flavonoids, guanidine derivatives, terpenoids, organic acids, and fatty acids, were identified from Plantago asiatica L., P. depressa Willd., and P. major L. Results showed significant differences in chemical components among the three species, particularly flavonoids. This study is the first to provide a comprehensive chemical profile of Plantaginis Semen, which could be involved into the quality control, medication guide, and developing new drug of Plantago seeds.

  5. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry reveals the correlation between chemical compounds in Japanese sake and its organoleptic properties.

    Science.gov (United States)

    Takahashi, Kei; Kabashima, Fumie; Tsuchiya, Fumihiko

    2016-03-01

    Japanese sake is a traditional alcoholic beverage composed of a wide variety of metabolites, which give it many types of tastes and flavors. Previously, we have reported that medium-chain fatty acids contribute to a fatty odor in sake (Takahashi, K., et al., J. Agric. Food Chem., 62, 8478-8485, 2014). In this study, we have reanalyzed the data obtained using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. The relationship between the chemical components in sake and specific organoleptic properties such as off-flavor and quality has been explored. This led to the identification of the type of chemical compounds present and an assessment of the numerous candidate compounds that correlate with such organoleptic properties in sake. This research provides important fundamental knowledge for the sake-brewing industry. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Characterization of gate oxynitrides by means of time of flight secondary ion mass spectrometry and x-ray photoelectron spectroscopy. Quantification of nitrogen

    CERN Document Server

    Ferrari, S; Fanciulli, M

    2002-01-01

    We present a methodology for the quantitative estimation of nitrogen in ultrathin oxynitrides by means of time of flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS). We consider an innovative approach to TOF-SIMS depth profiling, by elemental distribution of single species as sum of peaks containing such species. This approach is very efficient in overcoming matrix effect arising when quantifying elements were distributed in silicon and silicon oxide. We use XPS to calibrate TOF-SIMS and to obtain quantitative information on nitrogen distribution in oxynitride thin layers. In the method we propose we process TOF-SIMS and XPS data simultaneously to obtain a quantitative depth profile.

  7. Microbial typing by matrix-assisted laser desorption ionization-time of flight mass spectrometry: do we need guidance for data interpretation?

    Science.gov (United States)

    Spinali, Sébastien; van Belkum, Alex; Goering, Richard V; Girard, Victoria; Welker, Martin; Van Nuenen, Marc; Pincus, David H; Arsac, Maud; Durand, Géraldine

    2015-03-01

    The integration of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in clinical microbiology has revolutionized species identification of bacteria, yeasts, and molds. However, beyond straightforward identification, the method has also been suggested to have the potential for subspecies-level or even type-level epidemiological analyses. This minireview explores MALDI-TOF MS-based typing, which has already been performed on many clinically relevant species. We discuss the limits of the method's resolution and we suggest interpretative criteria allowing valid comparison of strain-specific data. We conclude that guidelines for MALDI-TOF MS-based typing can be developed along the same lines as those used for the interpretation of data from pulsed-field gel electrophoresis (PFGE).

  8. Liquidlike nature of crystalline n-butane and n-pentane films studied by time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Souda, Ryutaro

    2009-12-03

    Crystallization of vapor-deposited thin films of n-butane and n-pentane has been investigated using temperature-programmed time-of-flight secondary ion mass spectrometry. The morphology of thin n-butane (n-pentane) films changes at around the calorimetric crystallization temperature of 65 K (85 K) as a result of crystallization of the supercooled liquid. The morphology of the crystal grains of n-butane changes at 85 K; the butane molecules permeate through porous amorphous-solid-water films above this temperature. The crystal grains of n-pentane are smaller in size than those of n-butane, forming a smoother crystalline film. However, the crystalline n-pentane film dewets abruptly at higher temperatures, depending on the film thickness. The liquidlike nature of crystalline n-pentane (n-butane) is attributable to premelting (coexisting second liquid).

  9. Fast capillary electrophoresis-time-of-flight mass spectrometry using capillaries with inner diameters ranging from 75 to 5 μm.

    Science.gov (United States)

    Grundmann, Marco; Matysik, Frank-Michael

    2011-04-01

    Fast electrophoretic separations in fused silica capillaries (CE) coupled to time-of-flight mass spectrometry (TOF-MS) are presented. CE separations of the model analytes (epinephrine, norepinephrine, dopamine, histidine, and isoproterenol) under conditions of high electric field strengths of up to 1.25 kV cm(-1) are completed in 20 s. Coupling of CE with TOF-MS is accomplished using a coaxial sheath liquid electrospray ionization interface. The influence of parameters inherent to the interface and their effects, including suction pressure and dilution, are discussed. In addition to standard capillaries of 75 and 50 μm inner diameter (ID), separations in capillaries with IDs of 25, 15, and 5 μm have been successfully applied to this setup. The analytical performance is compared over this range of capillary dimensions, and both advantages and disadvantages are discussed.

  10. Qualitative analysis of major constituents from Xue Fu Zhu Yu Decoction using ultra high performance liquid chromatography with hybrid ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Fu, Chunyan; Xia, Zian; Liu, Yonghui; Lu, Hongmei; Zhang, Zhimin; Wang, Yang; Fan, Xiaqiong

    2016-09-01

    Xue Fu Zhu Yu Decoction, a famous formula that has been used for treating many blood stasis-caused diseases for many centuries, comprises 11 kinds of traditional Chinese medicines. A convenient, efficient, and rapid analytical method was developed to simultaneously determine the major compounds in this decoction. An ultra-high performance liquid chromatography with hybrid ion trap time-of-flight mass spectrometry method was used to rapidly separate and detect the major constituents of the decoction. Using this technique, we identified or tentatively identified 34 compounds, including 21 flavonoids, 5 terpenoids, 3 organic acids, 2 lactones, 1 alkaloid, 1 amino acid, and 1 cyanogenic glycoside. The MS analysis of these constituents was described in detail. Findings may contribute to future metabolic and pharmacokinetic studies of this medicine.

  11. Discrimination of leaves of Panax ginseng and P. quinquefolius by ultra high performance liquid chromatography quadrupole/time-of-flight mass spectrometry based metabolomics approach.

    Science.gov (United States)

    Mao, Qian; Bai, Min; Xu, Jin-Di; Kong, Ming; Zhu, Lin-Yin; Zhu, He; Wang, Qiang; Li, Song-Lin

    2014-08-01

    In present study, an ultra high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) based metabolomics approach was established to investigate the metabolic profiles and characteristic chemical markers for distinguishing between leaves of Panax ginseng (LPG) and Panax quinquefolius (LPQ). The UHPLC-QTOF-MS/MS data were subjected to principal component analysis (PCA) and orthogonal partial least squared discrimination analysis (OPLS-DA) to rapidly find the potential characteristic components of LPG and LPQ, and the identities of detected peaks including the potential characteristic components were elucidated. Totally, 86 components were identified from these 2 kinds of leaf samples, in which 9 ginsenosides could be regarded as the characteristic chemical markers for the discrimination of LPG from LPQ. These results suggested that UHPLC-QTOF-MS/MS based metabolomics approach is a powerful tool to rapidly find characteristic markers for the quality control of LPG.

  12. Analysis of Salvinorin A in plants, water, and urine using solid-phase microextraction-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry.

    Science.gov (United States)

    Barnes, Brian B; Snow, Nicholas H

    2012-02-24

    Salvinorin A, a psychoactive hallucinogen, and related compounds, were analyzed in plants, water, and urine using liquid-liquid extraction (LLE), solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-ToFMS). A semi-qualitative study of the extraction of Salvinorin A and analogs from Salvia divinorum plants by LLE showed ppb levels of Salvinorin A and several analogs in the leaves and stems of S. divinorum plants, much lower than expected. Quantitative analysis of Salvinorin A spiked into water and urine showed much better figures of merit for SPME than LLE, with limit of detection of about 5 ng/mL, linear range from 8 to 500 ng/mL and precision about ±10% for the SPME-based analyses using external standard quantitation. GC×GC-ToFMS was especially effective in separating the peaks of interest from matrix and chromatographic interferences.

  13. Adsorption behavior of poly(dimethyl-diallylammonium chloride) on pulp fiber studied by cryo-time-of-flight secondary ion mass spectrometry and cryo-scanning electron microscopy

    Science.gov (United States)

    Masumi, Takashi; Matsushita, Yasuyuki; Aoki, Dan; Takama, Ruka; Saito, Kaori; Kuroda, Katsushi; Fukushima, Kazuhiko

    2014-01-01

    In this study, the adsorption behavior of poly(dimethyl-diallylammonium chloride) (PDADMAC), a retention agent used in papermaking, in a dual polymer system with anionic poly(acrylamide) (A-PAM) was investigated by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Initially, fragment structures and cleavage patterns were identified via TOF-SIMS experiments with deuterium-labeled PDADMAC and the unlabeled analogue. Visualization of PDADMAC on a dry handsheet surface using traditional TOF-SIMS analysis indicated that the electrostatic interaction between coagulated PDADMAC and A-PAM was relatively weak. A novel cryo-TOF-SIMS/SEM system enabled the evaluation of a wet handsheet containing PDADMAC. Analysis of this sample indicated that PDADMAC adsorbs onto the fiber surface and collects preferentially on the tangled fibrils located between fibers.

  14. Screening and identification of various components in Thalictrum fortunei using a combination of liquid chromatography/time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Cheng, H X; Zeng, Y C; Jia, B Y; Fang, C F; Cheng, W M

    2012-02-01

    An approach for screening and identification of various components in a traditional Chinese medicine (TCM), using a combination of LC/TOF-MS technique was described in this paper. The chemical profile of Thalictrum fortunei, well-known in TCM, was studied using the established method. The possibilities of screening and identifying non-target components inside TCM with modern data acquisition methods of acceleration time of flight mass spectrometers, such as data-dependent MS to MS/MS switching were investigated. As a result, 27 components were identified. This study was aimed to screen and identify the main components of T. fortunei using LC/TOF-MS, expecting to provide a rapid, sensitive, economical and systematical method for the identification and further quality evaluation of TCM preparation.

  15. Determination of emerging contaminants in wastewater utilizing comprehensive two-dimensional gas-chromatography coupled with time-of-flight mass spectrometry.

    Science.gov (United States)

    Prebihalo, Sarah; Brockman, Adrienne; Cochran, Jack; Dorman, Frank L

    2015-11-06

    An analytical method for identification of emerging contaminants of concern, such as pesticides and organohalogens has been developed and utilized for true discovery-based analysis. In order to achieve the level of sensitivity and selectivity necessary for detecting compounds in complex samples, comprehensive gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) was utilized to analyze wastewater samples obtained from the Pennsylvania State University wastewater treatment facility (WWTF). Determination of emerging contaminants through a process of combining samples which represent "normal background" and comparing this to new samples was developed. Results show the presence of halogenated benzotriazoles in wastewater samples as well as soil samples from Pennsylvania State University agricultural fields. The trace levels of chlorinated benzotriazoles observed in the monitoring wells present on the property indicate likely environmental degradation of the chlorinated benzotriazoles. Preliminary investigation of environmental fate of the substituted benzotriazoles indicates their likely degradation into phenol; an Environmental Protection Agency (USEPA) priority pollutant.

  16. An extraction method of positive blood cultures for direct identification of Candida species by Vitek MS matrix-assisted laser desorption ionization time of flight mass spectrometry.

    Science.gov (United States)

    Lavergne, Rose-Anne; Chauvin, Pamela; Valentin, Alexis; Fillaux, Judith; Roques-Malecaze, Christine; Arnaud, Sylvie; Menard, Sandie; Magnaval, Jean-François; Berry, Antoine; Cassaing, Sophie; Iriart, Xavier

    2013-08-01

    Candida spp. are an important cause of nosocomial bloodstream infections. Currently, complete identification of yeasts with conventional methods takes several days. We report here the first evaluation of an extraction method associated with the Vitek MS matrix-assisted laser desorption ionization time of flight mass spectrometry for direct identification of Candida species from positive blood cultures. We evaluated this protocol with blood cultures that were inoculated with reference and routine isolates (eight reference strains, 30 patients isolates and six mixed cultures containing two strains of different Candida species), or from patients with candidemia (28 isolates). This method performed extremely well (97% correct identification) with blood cultures of single Candida spp. and significantly reduced the time of diagnosis. Nevertheless, subculture remains indispensable to test fungal resistance and to detect mixed infections.

  17. Adsorption behavior of poly(dimethyl-diallylammonium chloride) on pulp fiber studied by cryo-time-of-flight secondary ion mass spectrometry and cryo-scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Masumi, Takashi [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Matsushita, Yasuyuki, E-mail: ysmatsu@agr.nagoya-u.ac.jp [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Aoki, Dan [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Takama, Ruka [Technical Center, Nagoya University, Furo-cho Chikusa-ku Nagoya, Aichi 464-8601 (Japan); Saito, Kaori [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Kuroda, Katsushi [Department of Wood Properties, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687 (Japan); Fukushima, Kazuhiko [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)

    2014-01-15

    In this study, the adsorption behavior of poly(dimethyl-diallylammonium chloride) (PDADMAC), a retention agent used in papermaking, in a dual polymer system with anionic poly(acrylamide) (A-PAM) was investigated by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Initially, fragment structures and cleavage patterns were identified via TOF-SIMS experiments with deuterium-labeled PDADMAC and the unlabeled analogue. Visualization of PDADMAC on a dry handsheet surface using traditional TOF-SIMS analysis indicated that the electrostatic interaction between coagulated PDADMAC and A-PAM was relatively weak. A novel cryo-TOF-SIMS/SEM system enabled the evaluation of a wet handsheet containing PDADMAC. Analysis of this sample indicated that PDADMAC adsorbs onto the fiber surface and collects preferentially on the tangled fibrils located between fibers.

  18. A pre-processing strategy for liquid chromatography time-of-flight mass spectrometry metabolic fingerprinting data

    DEFF Research Database (Denmark)

    Nielsen, Nikoline Juul; Tomasi, Giorgio; Frandsen, Rasmus John Normand

    2010-01-01

    . It includes importing data into a computing environment by binning the m/z axis; baseline removal; data transformation and compression across retention times. Each sample represented by a total mass spectrum was normalized to unit sum and variables selected by partial least squares discriminant analysis...

  19. Technical Note: Performance of Chemical Ionization Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS for the measurement of atmospherically significant oxygenated volatile organic compounds

    Directory of Open Access Journals (Sweden)

    K. P. Wyche

    2007-01-01

    Full Text Available The performance of a new chemical ionization reaction time-of-flight mass spectrometer (CIR-TOF-MS utilising the environment chamber SAPHIR (Simulation of Atmospheric Photochemistry In a large Reaction Chamber- Forschungzentrum Jülich, Germany is described. The work took place as part of the ACCENT (Atmospheric Composition and Change the European NeTwork for excellence supported oxygenated volatile organic compound (OVOC measurement intercomparison during January 2005. The experiment entailed the measurement of 14 different atmospherically significant OVOCs at various mixing ratios in the approximate range 10.0–0.6 ppbV. The CIR-TOF-MS operated throughout the exercise with the hydronium ion (H3O+ as the primary chemical ionization (CI reagent in order to facilitate proton transfer to the analyte OVOCs. The results presented show that the CIR time-of-flight mass spectrometer is capable of detecting a wide range of atmospheric OVOCs at mixing ratios of around 10 ppbV in "real-time" (i.e. detection on the one-minute time scale, with sub-ppbV measurement also achieved following an increase in averaging time to tens of minutes. It is shown that in general OVOC measurement is made with high accuracy and precision, with integration time, mixing ratio and compound dependent values as good as 4–13% and 3–15% respectively. It is demonstrated that CIR-TOF-MS has rapid multi-channel response at the required sensitivity, accuracy and precision for atmospheric OVOC measurement.

  20. Discrimination between bacterial spore types using time-of-flight mass spectrometry and matrix-free infrared laser desorption and ionization.

    Science.gov (United States)

    Ullom, J N; Frank, M; Gard, E E; Horn, J M; Labov, S E; Langry, K; Magnotta, F; Stanion, K A; Hack, C A; Benner, W H

    2001-05-15

    We demonstrate that molecular ions with mass-to-charge ratios (m/z) ranging from a few hundred to 19 050 can be desorbed from whole bacterial spores using infrared laser desorption and no chemical matrix. We have measured the mass of these ions using time-of-flight mass spectrometry and we observe that different ions are desorbed from spores of Bacillus cereus, Bacillus thuringiensis, Bacillus subtilis, and Bacillus niger. Our results raise the possibility of identifying microorganisms using mass spectrometry without conventional sample preparation techniques such as the addition of a matrix. We have measured the dependence of the ion yield from B. subtilis on desorption wavelength over the range 3.05-3.8 microm, and we observe the best results at 3.05 microm. We have also generated mass spectra from whole spores using 337-nm ultraviolet laser desorption, and we find that these spectra are inferior to spectra generated with infrared desorption. Since aerosol analysis is a natural application for matrix-free desorption, we have measured mass spectra from materials such as ragweed pollen and road dust that are likely to form a background to microbial aerosols. We find that these materials are readily differentiated from bacterial spores.

  1. Direct analysis of silica gel extracts from immunostained glycosphingolipids by nanoelectrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Meisen, Iris; Peter-Katalinić, Jasna; Müthing, Johannes

    2004-04-15

    A combined strategy of preparative high-performance thin-layer chromatography overlay assay and mass spectrometry was established for the structural characterization of immunostained glycosphingolipids (GSLs) in silica gel extracts. Crude chloroform/methanol/water (30/60/8, v/v/v) extracts of immunostained TLC bands were analyzed by nanoelectrospray low-energy CID mass spectrometry without further purification. The GSL species investigated were isomeric monosialogangliosides of the neolacto series from a ganglioside preparation of human granulocytes, the disialoganglioside GD3 from a human melanoma lipid extract, and ganglio series Gg3Cer of a neutral GSL preparation from murine lymphoreticular MDAY-D2 cells. For the specific detection of lipid-bound oligosaccharides, polyclonal chicken IgY, murine monoclonal IgG3, and IgM antibodies were used. The resulting mass spectra show that only analytical quantities of approximately 1 microg of a single GSL within a complex mixture are required for the structure determination of immunostained GSLs by MS and MS/MS. All species investigated were detected as singly charged deprotonated molecular ions, and neither buffer-derived salt adducts nor coextracted contaminants from the immunostaining procedure or the silica gel layer were observed. This effective HPTLC-MS-joined procedure offers a wide range of applications for any carbohydrate binding agents such as bacterial toxins, plant lectins, and others.

  2. Dereplication of known nucleobase and nucleoside compounds in natural product extracts by capillary electrophoresis-high resolution mass spectrometry.

    Science.gov (United States)

    Chen, Junhui; Shi, Qian; Wang, Yanlong; Li, Zhaoyong; Wang, Shuai

    2015-03-26

    Nucleobase and nucleoside compounds exist widely in various organisms. An often occurring problem in the discovery of new bioactive compounds from natural products is reisolation of known nucleobase and nucleoside compounds. To resolve this problem, a capillary electrophoresis-high resolution mass spectrometry (CE-HR-MS) method providing both rapid separation and accurate mass full-scan MS data was developed for the first time to screen and dereplicate known nucleobase and nucleoside compounds in crude extracts of natural products. Instrumental parameters were optimized to obtain optimum conditions for CE separation and electrospray ionization-time-of-flight mass spectrometry (ESI-TOF/MS) detection. The proposed method was verified to be precise, reproducible, and sensitive. Using this method, known nucleobase and nucleoside compounds in different marine medicinal organisms including Syngnathus acus Linnaeus; Hippocampus japonicus Kaup and Anthopleura lanthogrammica Berkly were successfully observed and identified. This work demonstrates that CE-HR-MS combined with an accurate mass database may be used as a powerful tool for dereplicating known nucleobase and nucleoside compounds in different types of natural products. Rapid dereplication of known nucleobase and nucleoside compounds allows researchers to focus on other leads with greater potential to yield new substances.

  3. Dereplication of Known Nucleobase and Nucleoside Compounds in Natural Product Extracts by Capillary Electrophoresis-High Resolution Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Junhui Chen

    2015-03-01

    Full Text Available Nucleobase and nucleoside compounds exist widely in various organisms. An often occurring problem in the discovery of new bioactive compounds from natural products is reisolation of known nucleobase and nucleoside compounds. To resolve this problem, a capillary electrophoresis-high resolution mass spectrometry (CE-HR-MS method providing both rapid separation and accurate mass full-scan MS data was developed for the first time to screen and dereplicate known nucleobase and nucleoside compounds in crude extracts of natural products. Instrumental parameters were optimized to obtain optimum conditions for CE separation and electrospray ionization-time-of-flight mass spectrometry (ESI-TOF/MS detection. The proposed method was verified to be precise, reproducible, and sensitive. Using this method, known nucleobase and nucleoside compounds in different marine medicinal organisms including Syngnathus acus Linnaeus; Hippocampus japonicus Kaup and Anthopleura lanthogrammica Berkly were successfully observed and identified. This work demonstrates that CE-HR-MS combined with an accurate mass database may be used as a powerful tool for dereplicating known nucleobase and nucleoside compounds in different types of natural products. Rapid dereplication of known nucleobase and nucleoside compounds allows researchers to focus on other leads with greater potential to yield new substances.

  4. Quantitative proteomics using the high resolution accurate mass capabilities of the quadrupole-orbitrap mass spectrometer.

    Science.gov (United States)

    Gallien, Sebastien; Domon, Bruno

    2014-08-01

    High resolution/accurate mass hybrid mass spectrometers have considerably advanced shotgun proteomics and the recent introduction of fast sequencing capabilities has expanded its use for targeted approaches. More specifically, the quadrupole-orbitrap instrument has a unique configuration and its new features enable a wide range of experiments. An overview of the analytical capabilities of this instrument is presented, with a focus on its application to quantitative analyses. The high resolution, the trapping capability and the versatility of the instrument have allowed quantitative proteomic workflows to be redefined and new data acquisition schemes to be developed. The initial proteomic applications have shown an improvement of the analytical performance. However, as quantification relies on ion trapping, instead of ion beam, further refinement of the technique can be expected.

  5. Analysis of Microbial Mixtures by Matrix-assisted Laser Desorption/Ionization time-of-flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Karen L.; Wunschel, Sharon C.; Jarman, Kristin H.; Valentine, Nancy B.; Petersen, Catherine E.; Kingsley, Mark T.; Zartolas, Kimberly A.; Saenz, Adam J.

    2002-12-15

    Many different laboratories are currently developing mass-spectrometric techniques to analyze and identify microorganisms. However, minimal work has been done with mixtures of bacteria. To demonstrate that microbial mixtures could be analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), mixed bacterial cultures were analyzed in a double-blind fashion. Nine different bacterial species currently in our MALDI-MS fingerprint library were used to generate 50 different simulated mixed bacterial cultures similar to that done for an initial blind study previously reported.(1) The samples were analyzed by MALDI-MS with automated data extraction and analysis algorithms developed in our laboratory. The components present in the sample were identified correctly to the species level in all but one of the samples. However, correctly eliminating closely related organisms was challenging for the current algorithms, especially in differentiating Serratia marcescens, Escherichia coli, and Yersinia enterocolitica, which have some similarities in their MALDI-MS fingerprints. Efforts to improve the specificity of the algorithms are in progress.

  6. Potential of gas chromatography-atmospheric pressure chemical ionization-time-of-flight mass spectrometry for the determination of sterols in human plasma.

    Science.gov (United States)

    Matysik, S; Schmitz, G; Bauer, S; Kiermaier, J; Matysik, F-M

    2014-04-11

    The application of Gas Chromatography (GC)-Atmospheric Pressure Chemical Ionization (APCI)-Time-of-Flight Mass Spectrometry (TOF-MS) is presented for sterol analysis in human plasma. A commercial APCI interface was modified to ensure a well-defined humidity which is essential for controlled ionization. In the first step, optimization regarding flow rates of auxiliary gases was performed by using a mixture of model analytes. Secondly, the qualitative and quantitative analysis of sterols including oxysterols, cholesterol precursors, and plant sterols as trimethylsilyl-derivatives was successfully carried out. The characteristics of APCI together with the very good mass accuracy of TOF-MS data enable the reliable identification of relevant sterols in complex matrices. Linear calibration lines and plausible results for healthy volunteers and patients could be obtained whereas all mass signals were extracted with an extraction width of 20 ppm from the full mass data set. One advantage of high mass accuracy can be seen in the fact that from one recorded run any search for m/z can be performed. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Time-of-flight mass measurements of neutron-rich chromium isotopes up to N = 40 and implications for the accreted neutron star crust

    CERN Document Server

    Meisel, Z; Ahn, S; Bazin, D; Brown, B A; Browne, J; Carpino, J F; Chung, H; Cyburt, R H; Estradé, A; Famiano, M; Gade, A; Langer, C; Matoš, M; Mittig, W; Montes, F; Morrissey, D J; Pereira, J; Schatz, H; Schatz, J; Scott, M; Shapira, D; Sieja, K; Smith, K; Stevens, J; Tan, W; Tarasov, O; Towers, S; Wimmer, K; Winkelbauer, J R; Yurkon, J; Zegers, R G T

    2016-01-01

    We present the mass excesses of 59-64Cr, obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The mass of 64Cr is determined for the first time, with an atomic mass excess of -33.48(44) MeV. We find a significantly different two-neutron separation energy S2n trend for neutron-rich isotopes of chromium, removing the previously observed enhancement in binding at N=38. Additionally, we extend the S2n trend for chromium to N=40, revealing behavior consistent with the previously identified island of inversion in this region. We compare our results to state-of-the-art shell-model calculations performed with a modified Lenzi-Nowacki-Poves-Sieja interaction in the fp shell, including the g9/2 and d5/2 orbits for the neutron valence space. We employ our result for the mass of 64Cr in accreted neutron star crust network calculations and find a reduction in the strength and depth of electron-capture heating from the A=64 isobaric...

  8. Status and perspective of a new time-of-flight detector for the isochronous mass spectrometry in the collector ring at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Diwisch, Marcel [Justus-Liebig-University Giessen (Germany); Kuzminchuk-Feuerstein, Natalia; Geissel, Hans; Knoebel, Ronja; Dickel, Timo; Plass, Wolfgang; Scheidenberger, Christoph [Justus-Liebig-University Giessen (Germany); GSI, Darmstadt (Germany); Weick, Helmut [GSI, Darmstadt (Germany)

    2014-07-01

    The masses of exotic nuclei can be measured directly in ion storage rings by measuring their revolution time in the ring. In the presently used FRS-ESR facility one method to do this is the so called Isochronous Mass Spectrometry (IMS). With the IMS method mass values of exotic nuclei with lifetimes as short as a few 10 μs are accessible. To determine the masses the revolution time of the ions in the ring is measured by a Time-Of-Flight (TOF) detector. The future Collector Ring (CR) will be different compared to the current ESR not only in circumference but also in terms of beam dimensions and intensities. In order to use an advanced version of the IMS in the CR a new double detector system, which improves the mass resolution of the IMS method and fulfills the requirements of the new beam dimensions will be shown. Improvements of almost a factor 2 for the timing accuracy with at least 95% detection efficiency is expected compared to the current design, even though the detector dimensions had to be increased by a factor of 2 to adapt to the new beam dimensions.

  9. An improved method for the determination of 5-hydroxymethylfurfural in Shenfu injection by direct analysis in real time-quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Gao, Wen; Qi, Lian-Wen; Liu, Charles C; Wang, Rui; Li, Ping; Yang, Hua

    2016-07-01

    The emergence of direct analysis in real time (DART) ion source provides the great possibility for rapid analysis of hazardous substance in drugs. DART mass spectrometry (DART-MS) enabled the conducting of a fast and non-contact analysis of various samples, including solid or liquid ones, without complex sample preparation or chromatographic separation. In this study, a modified DART-quadrupole time-of-flight mass spectrometry (DART-QTOF-MS) method was developed for identification and determination of 5-hydroxymethylfurfural (5-HMF) in Shenfu (SF) injection. The quantitative transfer of sample solution was introduced to the glass tips of DIP-it sampler at a fixed volume, which significantly increases the repeatability and accuracy of analytical results. The protonated ion of dibutyl phthalate in the atmosphere was used as the reference mass for TOF-MS recalibration during the data acquisition for constant high accuracy mass measurements. Finally, the developed DART-MS method was used to determine 5-HMF in seven batches of SF injection, and the contents of 5-HMF were not higher than 100 µg/mL. The results obtained were further confirmed by an ultra-high performance liquid chromatography combined with triple quadrupole mass spectrometer (UHPLC-QQQ-MS). The overall results demonstrated that the DART-QTOF-MS method could be applied as an alternative technique for rapid monitoring 5-HMF in herbal medicine injection. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Quantitative matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis of synthetic polymers and peptides.

    Science.gov (United States)

    Hyzak, Lukas; Moos, Rebecca; von Rath, Friederike; Wulf, Volker; Wirtz, Michaela; Melchior, David; Kling, Hans-Willi; Köhler, Michael; Gäb, Siegmar; Schmitz, Oliver J

    2011-12-15

    Matrix-assisted laser desorption ionization (MALDI) is a very powerful and widely used mass spectrometric technique to ionize high molecular weight compounds. The most commonly used dried droplet (DD) technique can lead to a concentration distribution of the analyte on the target and is therefore often not suitable for reproducible analyses. We developed a new solvent-free deposition technique, called compressed sample (CS), to prevent the distribution of the analytes caused by the crystallization of the compounds. The CS technique presented in this work allows the quantitative analysis of synthetic polymers such as derivatized maltosides with correlation coefficients of 0.999 and peptides up to 3500 Da with correlation coefficients of at least 0.982 without the use of stable-isotope-labeled standards.

  11. Comprehensive characterisation of flame retardants in textile furnishings by ambient high resolution mass spectrometry, gas chromatography-mass spectrometry and environmental forensic microscopy.

    Science.gov (United States)

    Ionas, Alin C; Ballesteros Gómez, Ana; Uchida, Natsuyo; Suzuki, Go; Kajiwara, Natsuko; Takata, Kyoko; Takigami, Hidetaka; Leonards, Pim E G; Covaci, Adrian

    2015-10-01

    The presence and levels of flame retardants (FRs), such as polybrominated diphenyl ethers (PBDEs) and organophosphate flame retardants (PFRs), was determined in textile home furnishings, such as carpets and curtains from stores in Belgium. A comprehensive characterisation of FRs in textile was done by ambient high resolution mass spectrometry (qualitative screening), gas chromatography-mass spectrometry (GC-MS) (quantitation), and environmental forensic microscopy (surface distribution). Ambient ionisation coupled to a time-of-flight (TOF) high resolution mass spectrometer (direct probe-TOF-MS) was investigated for the rapid screening of FRs. Direct probe-TOF-MS proved to be useful for a first screening step of textiles to detect FRs below the levels required to impart flame retardancy and to reduce, in this way, the number of samples for further quantitative analysis. Samples were analysed by GC-MS to confirm the results obtained by ambient mass spectrometry and to obtain quantitative information. The levels of PBDEs and PFRs were typically too low to impart flame retardancy. Only high levels of BDE-209 (11-18% by weight) were discovered and investigated in localised hotspots by employing forensic microscopy techniques. Most of the samples were made of polymeric materials known to be inherently flame retarded to some extent, so it is likely that other alternative and halogen-free FR treatments/solutions are preferred for the textiles on the Belgian market. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Determination of trace rare earth elements in gadolinium aluminate by inductively coupled plasma time of flight mass spectrometry

    Science.gov (United States)

    Saha, Abhijit; Deb, S. B.; Nagar, B. K.; Saxena, M. K.

    An analytical methodology was developed for the precise quantification of ten trace rare earth elements (REEs), namely, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, and Tm, in gadolinium aluminate (GdAlO3) employing an ultrasonic nebulizer (USN)-desolvating device based inductively coupled plasma mass spectrometry (ICP-MS). A microwave digestion procedure was optimized for digesting 100 mg of the refractory oxide using a mixture of sulphuric acid (H2SO4), phosphoric acid (H3PO4) and water (H2O) with 1400 W power, 10 min ramp and 60 min hold time. An USN-desolvating sample introduction system was employed to enhance analyte sensitivities by minimizing their oxide ion formation in the plasma. Studies on the effect of various matrix concentrations on the analyte intensities revealed that precise quantification of the analytes was possible with matrix level of 250 mg L- 1. The possibility of using indium as an internal standard was explored and applied to correct for matrix effect and variation in analyte sensitivity under plasma operating conditions. Individual oxide ion formation yields were determined in matrix matched solution and employed for correcting polyatomic interferences of light REE (LREE) oxide ions on the intensities of middle and heavy rare earth elements (MREEs and HREEs). Recoveries of ≥ 90% were achieved for the analytes employing standard addition technique. Three real samples were analyzed for traces of REEs by the proposed method and cross validated for Eu and Nd by isotope dilution mass spectrometry (IDMS). The results show no significant difference in the values at 95% confidence level. The expanded uncertainty (coverage factor 1σ) in the determination of trace REEs in the samples were found to be between 3 and 8%. The instrument detection limits (IDLs) and the method detection limits (MDLs) for the ten REEs lie in the ranges 1-5 ng L- 1 and 7-64 μg kg- 1 respectively.

  13. Tropical Greenhouse Measurements of Volatile Organic Compounds Using Switchable Reagent Ion Proton-Transfer-Reaction Time-of-Flight Mass Spectromety (PTR-TOF-MS)

    Science.gov (United States)

    Veres, P.; Auld, J.; Williams, J.

    2012-04-01

    In this presentation, we will summarize the results of measurements made in an approximately 1300 m3 tropical greenhouse at the Johannes Gutenberg University botanical garden in Mainz Germany conducted over a one month period. The greenhouse is home to a large variety of plant species from hot and humid regions of the world. The greenhouse is also host to several crops such as Cocoa and Cola Nut as well as ornamental plants. A particular focus of the species maintained are those which are considered ant plants, or plants which have an intimate relationship with ants in tropical habitats. Volatile organic compounds (VOCs) were measured using a Switchable Reagent Ion Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS) using H3O+, NO+, and O2+ ion chemistry. Measurements will be presented both for primary emissions observed in the closed greenhouse atmosphere as well as the oxidation products observed after the introduction of ambient ozone. The high resolving power (5000 m/Δm) of the time-of-flight instrument allows for the separation of isobaric species. In particular, both isoprene (68.1170 amu) and furan (68.0740 amu) were observed and separated as primary emissions during this study. The significance of this will be discussed in terms of both atmospheric implications as well as with respect to previous measurements of isoprene obtained using quadrupole PTR-MS where isobaric separation of these compounds is not possible. Additionally observed species (e.g. Methanol, Acetaldehyde, MVK and MEK) will be discussed in detail with respect to their behavior as a function of light, temperature and relative humidity. The overall instrument performance of the PTR-TOF-MS technique using the H3O+, NO+, and O2+ primary ions for the measurement of VOCs will be evaluated.

  14. Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

    Science.gov (United States)

    Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

    2008-12-01

    The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the

  15. Determination of trace rare earth elements in gadolinium aluminate by inductively coupled plasma time of flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Abhijit; Deb, S.B.; Nagar, B.K.; Saxena, M.K., E-mail: saxenamk@barc.gov.in

    2014-04-01

    An analytical methodology was developed for the precise quantification of ten trace rare earth elements (REEs), namely, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, and Tm, in gadolinium aluminate (GdAlO{sub 3}) employing an ultrasonic nebulizer (USN)-desolvating device based inductively coupled plasma mass spectrometry (ICP-MS). A microwave digestion procedure was optimized for digesting 100 mg of the refractory oxide using a mixture of sulphuric acid (H{sub 2}SO{sub 4}), phosphoric acid (H{sub 3}PO{sub 4}) and water (H{sub 2}O) with 1400 W power, 10 min ramp and 60 min hold time. An USN-desolvating sample introduction system was employed to enhance analyte sensitivities by minimizing their oxide ion formation in the plasma. Studies on the effect of various matrix concentrations on the analyte intensities revealed that precise quantification of the analytes was possible with matrix level of 250 mg L{sup −1}. The possibility of using indium as an internal standard was explored and applied to correct for matrix effect and variation in analyte sensitivity under plasma operating conditions. Individual oxide ion formation yields were determined in matrix matched solution and employed for correcting polyatomic interferences of light REE (LREE) oxide ions on the intensities of middle and heavy rare earth elements (MREEs and HREEs). Recoveries of ≥ 90% were achieved for the analytes employing standard addition technique. Three real samples were analyzed for traces of REEs by the proposed method and cross validated for Eu and Nd by isotope dilution mass spectrometry (IDMS). The results show no significant difference in the values at 95% confidence level. The expanded uncertainty (coverage factor 1σ) in the determination of trace REEs in the samples were found to be between 3 and 8%. The instrument detection limits (IDLs) and the method detection limits (MDLs) for the ten REEs lie in the ranges 1–5 ng L{sup −1} and 7–64 μg kg{sup −1} respectively. - Highlights: • A

  16. Analysis of Photoablation Products Resulting from Polymer Materials by Supersonic Beam/Multiphoton Ionization/Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Lin, C H; Murata, Y; Imasaka, T

    1996-04-01

    Photoablation products arising from polymer materials were examined by supersonic beam spectrometry, and the results are compared with those obtained by thermal decomposition. The high selectivity provided by supersonic beam spectrometry allows detection of minor species, e.g., styrene occurred from poly(α-methylstyrene) by cleavage of a methyl group and by proton rearrangement. Because ablation techniques involve high temperatures, thermally stable materials such as poly(p-methylstyrene) can be examined. The latter material is difficult to examine by thermal decomposition, even at 350 °C. It is also possible to differentiate between isomer ablation products, e.g., α-methylstyrene and p-methylstyrene. The instrumental setup described herein was used to examine several authentic samples, such as ABS resin (acrylonitrile-butadiene-styrene) and O-ring (SBR, styrene-butadiene rubber), as well as polystyrene foam. As a result, a styrene segment could be confirmed to be present in these materials. However, no evidence was found for its presence in a glue sample that was suspected to contain styrene on the basis of conventional mass spectrometry. The latter finding confirms the high degree of selectivity of the technique.

  17. Quantification of genetically modified soya using strong anion exchange chromatography and time-of-flight mass spectrometry.

    Science.gov (United States)

    Chang, Po-Chih; Reddy, P Muralidhar; Ho, Yen-Peng

    2014-09-01

    Stable-isotope dimethyl labeling was applied to the quantification of genetically modified (GM) soya. The herbicide-resistant gene-related protein 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) was labeled using a dimethyl labeling reagent, formaldehyde-H2 or -D2. The identification and quantification of CP4 EPSPS was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The CP4 EPSPS protein was separated from high abundance proteins using strong anion exchange chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, the tryptic peptides from the samples and reference were labeled with formaldehyde-H2 and formaldehyde-D2, respectively. The two labeled pools were mixed and analyzed using MALDI-MS. The data showed a good correlation between the peak ratio of the H- and D-labeled peptides and the GM soya percentages at 0.5, 1, 3, and 5 %, with R (2) of 0.99. The labeling reagents are readily available. The labeling experiments and the detection procedures are simple. The approach is useful for the quantification of GM soya at a level as low as 0.5 %.

  18. Multiresidue Screening of Veterinary Drugs in Meat, Milk, Egg, and Fish Using Liquid Chromatography Coupled with Ion Trap Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Kang, JeongWoo; Park, Su-Jeong; Park, Hae-Chul; Hossain, Md Akil; Kim, Myeong-Ae; Son, Seong-Wan; Lim, Chae-Mi; Kim, Tae-Wan; Cho, Byung-Hoon

    2017-06-01

    New approaches to veterinary drug screening based on liquid chromatography-mass spectrometry (LC-MS/MS) and time-of-flight mass spectrometry (ToF/MS) are rapid and have high selectivity and sensitivity. In this study, we developed a multiresidue method for screening over 100 veterinary drug residues using ion trap (IT)-ToF/MS. The screened compounds comprised major drug classes used in veterinary practice, representing the following: amphenicols, anthelmintics, benzimidazoles, β-lactams, coccidiostats, ionophores, macrolides, non-steroidal anti-inflammatory drugs, quinolones, sulfonamides, tetracyclines, and tranquilizers. The method was developed based on chromatographic retention time, specific accurate mass, isotope distribution, and fragment data. Each compound was validated at three levels, and the mass accuracy, accuracy, and repeatability were calculated. All parameters showed acceptable values and conformed to the Commission Decision 2002/657/EC criteria. This screening method can simultaneously analyze over 100 veterinary drugs in meat, milk, eggs, and fish in a single analytical run.

  19. [Coupling of gas chromatography with single photon ionization time-of-flight mass spectrometry and its application to characterization of compounds in diesel].

    Science.gov (United States)

    Xie, Yuanyuan; Hua, Lei; Chen, Ping; Hou, Keyong; Jiang, Jichun; Wang, Yan; Li, Haiyang

    2015-02-01

    A novel analytical method coupling gas chromatography (GC) with single photon ionization time-of-flight mass spectrometry (SPI-TOF MS) has been developed. First of all, a double-wall-tube transfer line was built to combine GC with SPI-TOF MS, which realized seamless connection between GC and SPI ion source. Based on this, standard n-pentadecane and benzene/toluene/xylene standard gas mixtures were used to study important voltage parameters of the ion source. After the optimization of the ion source voltages, pure molecular ion peaks of the analytes were obtained in the mass spectra and qualitative analysis of different kinds of organic compounds were eventually realized rapidly and accurately. At last, GC/SPI-TOF MS was applied to the characterization of volatile and semvolatile organic compounds in diesel and two-dimensional spectra of GC×SPI-TOF MS were obtained. Without complicated spectra interpretation and data processing, volatile and semi-volatile organic compounds in diesel have been classified qualitatively by ion mass-to-charge ratio (m/z) in SPI mass spectra, including aliphatic compounds, aromatic compounds and nitrogen-containing compounds with low concentration such as benzopyrroles. Isomeric compounds in diesel were separated and identified by retention times of chromatographic peaks. The results indicate that the proposed analytical method of GC/SPI-TOF MS is suitable for the characterization of complicated samples such as diesel and environmental pollutants with easy operation and high efficiency.

  20. A general screening method for doping agents in human urine by solid phase extraction and liquid chromatography/time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kolmonen, Marjo [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland) and Doping Control Laboratory, United Laboratories Ltd., Helsinki (Finland)]. E-mail: marjo.kolmonen@helsinki.fi; Leinonen, Antti [Doping Control Laboratory, United Laboratories Ltd., Helsinki (Finland); Pelander, Anna [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland); Ojanperae, Ilkka [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland)

    2007-02-28

    A general screening method based on solid phase extraction (SPE) and liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) was developed and investigated with 124 different doping agents, including stimulants, {beta}-blockers, narcotics, {beta}{sub 2}-adrenergic agonists, agents with anti-estrogenic activity, diuretics and cannabinoids. Mixed mode cation exchange/C8 cartridges were applied to SPE, and chromatography was based on gradient elution on a C18 column. Ionization of the analytes was achieved with electrospray ionization in the positive mode. Identification by LC/TOFMS was based on retention time, accurate mass and isotopic pattern. Validation of the method consisted of analysis of specificity, analytical recovery, limit of detection and repeatability. The minimum required performance limit (MRPL), established by World Anti-Doping Agency (WADA), was attained to 97 doping agents. The extraction recoveries varied between 33 and 98% and the median was 58%. Mass accuracy was always better than 5 ppm, corresponding to a maximum mass error of 0.7 mDa. The repeatability of the method for spiked urine samples, expressed as median of relative standard deviations (RSD%) at concentrations of MRPL and 10 times MRPL, were 14% and 9%, respectively. The suitability of the LC/TOFMS method for doping control was demonstrated with authentic urine samples.

  1. Development of a linear ion trap/orthogonal-time-of-flight mass spectrometer for time-dependent observation of product ions by ultraviolet photodissociation of peptide ions.

    Science.gov (United States)

    Kim, Tae-Young; Schwartz, Jae C; Reilly, James P

    2009-11-01

    A hybrid linear ion trap/orthogonal time-of-flight (TOF) mass spectrometer has been developed to observe time-dependent vacuum ultraviolet photodissociation product ions. In this apparatus, a reflectron TOF mass analyzer is orthogonally interfaced to an LTQ using rf-only octopole and dc quadrupole ion guides. Precursor ions are generated by electrospray ionization and isolated in the ion trap. Subsequently they are directed to the TOF source where photodissociation occurs and product ions are extracted for mass analysis. To detect photodissociation product ions having axially divergent trajectories, a large rectangular detector is utilized. With variation of the time between photodissociation and orthogonal extraction in the TOF source, product ions formed over a range of times after photoexcitation can be sampled. Time-dependent observation of product ions following 157 nm photodissociation of a singly charged tryptic peptide ion (NWDAGFGR) showed that prompt photofragment ions (x- and v-type ions) dominate the tandem mass spectrum up to 1 micros after the laser shot, but the intensities of low energy thermal fragment ions (y-type ions) become comparable several microseconds later. Different proton mobilization time scales were observed for arginine- and lysine-terminated tryptic peptides.

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

    Science.gov (United States)

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

    2011-12-01

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

  3. Investigation of isomeric flavanol structures in black tea thearubigins using ultraperformance liquid chromatography coupled to hybrid quadrupole/ion mobility/time of flight mass spectrometry.

    Science.gov (United States)

    Yassin, Ghada H; Grun, Christian; Koek, Jean H; Assaf, Khaleel I; Kuhnert, Nikolai

    2014-11-01

    Ultra performance liquid chromatography (UPLC) when coupled to ion mobility (IMS)/orthogonal acceleration time of flight mass spectrometry is a suitable technique for analyzing complex mixtures such as the black tea thearubigins. With the aid of this advanced instrumental analysis, we were able to separate and identify different isomeric components in the complex mixture which could previously not be differentiated by a conventional high performance liquid chromatography/tandem mass spectrometry. In this study, the difference between isomeric structures theasinensins, proanthocyanidins B-type and rutin (quercetin-3O-rutinoside) were studied, and these are present abundantly in many botanical sources. The differentiation between these structures was accomplished according to their acquired mobility drift times differing from the traditional investigations in mass spectrometry, where calculation of theoretical collisional cross sections allowed assignment of the individual isomeric structures. The present work demonstrates UPLC-IMS-MS as an efficient technology for isolating and separating isobaric and isomeric structures existing in complex mixtures discriminating between them according to their characteristic fragment ions and mobility drift times. Therefore, a rational assignment of isomeric structures in many phenolic secondary metabolites based on the ion mobility data might be useful in mass spectrometry-based structure analysis in the future.

  4. Novel approaches in analysis of Fusarium mycotoxins in cereals employing ultra performance liquid chromatography coupled with high resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zachariasova, M.; Lacina, O.; Malachova, A.; Kostelanska, M.; Poustka, J. [Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic); Godula, M. [Thermo Fisher Scientific, Czech Republic, Slunecna 27, 100 00 Prague 10 (Czech Republic); Hajslova, J., E-mail: jana.hajslova@vscht.cz [Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic)

    2010-03-03

    Rapid, simple and cost-effective analytical methods with performance characteristics matching regulatory requirements are needed for effective control of occurrence of Fusarium toxins in cereals and cereal-based products to which they might be transferred during processing. Within this study, two alternative approaches enabling retrospective data analysis and identification of unknown signals in sample extracts have been implemented and validated for determination of 11 major Fusarium toxins. In both cases, ultra-high performance liquid chromatography (U-HPLC) coupled with high resolution mass spectrometry (HR MS) was employed. {sup 13}C isotopically labeled surrogates as well as matrix-matched standards were employed for quantification. As far as time of flight mass analyzer (TOF-MS) was a detection tool, the use of modified QuEChERS (quick easy cheap effective rugged and safe) sample preparation procedure, widely employed in multi-pesticides residue analysis, was shown as an optimal approach to obtain low detection limits. The second challenging alternative, enabling direct analysis of crude extract, was the use of mass analyzer based on Orbitrap technology. In addition to demonstration of full compliance of the new methods with Commission Regulation (EC) No. 401/2006, also their potential to be used for confirmatory purposes according to Commission Decision 2002/657/EC has been critically assessed.

  5. Characterization of a time-of-flight mass spectrometer and its applications in the study of solid surfaces; Charakterisierung eines Flugzeitmassenspektrometers und seine Anwendungen in der Festkoerperoberflaechenuntersuchung

    Energy Technology Data Exchange (ETDEWEB)

    Mazarov, P.

    2006-12-21

    The object and the purpose of the present work was to develop, to assemble and to start running a new TOF (time of flight) mass spectrometer for imaging SNMS analytic which is optimized for the analysis of highly molecular secondary ions. The most important purpose was the characterization of the TOF mass spectrometer. The obtained mass spectra of indium, tantalum and silver clusters reflect the excellent properties of the TOF mass spectrometer for the detection of large clusters with good detection efficiency up to masses of 16000 amu. The possibility of the deflection of selected saturated atom and cluster peaks serves for further improvement of the detection efficiency for large molecules. The accessible mass resolution was determined to be of the order of m/{delta}m=1000 in the high mass region. Numerous measurements were carried out to characterize the useful yield of this spectrometer. For a best possible adaptation of the TOF mass spectrometer for the detection of highly molecular particles, a device for post-acceleration of the detected particles by up to 10 keV were inserted directly before the MCP detector. The detection efficiency of positive secondary ions was determined for different post-acceleration voltages for the example of sputtered indium cluster ions. In addition, a new method was developed for the quantitative determination of the spectral ionization probability {alpha}{sup +}({nu}) of sputtered particles as a function of the emission velocity. The next application of the TOF mass spectrometer is the analysis of complicated organic molecules in solid state surfaces. During measurements of the photo-ionization behaviour of neutral tryptophan molecules, it was found out that a stable molecular ion signal is generated in the SNMS spectrum with h{nu}=7.9 eV can only be observed by the use of a continuous ion beam or very long (ms range) ion pulses. (orig.)

  6. A new, high-resolution global mass coral bleaching database.

    Science.gov (United States)

    Donner, Simon D; Rickbeil, Gregory J M; Heron, Scott F

    2017-01-01

    Episodes of mass coral bleaching have been reported in recent decades and have raised concerns about the future of coral reefs on a warming planet. Despite the efforts to enhance and coordinate coral reef monitoring within and across countries, our knowledge of the geographic extent of mass coral bleaching over the past few decades is incomplete. Existing databases, like ReefBase, are limited by the voluntary nature of contributions, geographical biases in data collection, and the variations in the spatial scale of bleaching reports. In this study, we have developed the first-ever gridded, global-scale historical coral bleaching database. First, we conducted a targeted search for bleaching reports not included in ReefBase by personally contacting scientists and divers conducting monitoring in under-reported locations and by extracting data from the literature. This search increased the number of observed bleaching reports by 79%, from 4146 to 7429. Second, we employed spatial interpolation techniques to develop annual 0.04° × 0.04° latitude-longitude global maps of the probability that bleaching occurred for 1985 through 2010. Initial results indicate that the area of coral reefs with a more likely than not (>50%) or likely (>66%) probability of bleaching was eight times higher in the second half of the assessed time period, after the 1997/1998 El Niño. The results also indicate that annual maximum Degree Heating Weeks, a measure of thermal stress, for coral reefs with a high probability of bleaching increased over time. The database will help the scientific community more accurately assess the change in the frequency of mass coral bleaching events, validate methods of predicting mass coral bleaching, and test whether coral reefs are adjusting to rising ocean temperatures.

  7. High resolution weak lensing mass mapping combining shear and flexion

    Science.gov (United States)

    Lanusse, F.; Starck, J.-L.; Leonard, A.; Pires, S.

    2016-06-01

    Aims: We propose a new mass mapping algorithm, specifically designed to recover small-scale information from a combination of gravitational shear and flexion. Including flexion allows us to supplement the shear on small scales in order to increase the sensitivity to substructures and the overall resolution of the convergence map without relying on strong lensing constraints. Methods: To preserve all available small scale information, we avoid any binning of the irregularly sampled input shear and flexion fields and treat the mass mapping problem as a general ill-posed inverse problem, which is regularised using a robust multi-scale wavelet sparsity prior. The resulting algorithm incorporates redshift, reduced shear, and reduced flexion measurements for individual galaxies and is made highly efficient by the use of fast Fourier estimators. Results: We tested our reconstruction method on a set of realistic weak lensing simulations corresponding to typical HST/ACS cluster observations and demonstrate our ability to recover substructures with the inclusion of flexion, which are otherwise lost if only shear information is used. In particular, we can detect substructures on the 15'' scale well outside of the critical region of the clusters. In addition, flexion also helps to constrain the shape of the central regions of the main dark matter halos. Our mass mapping software, called Glimpse2D, is made freely available at http://www.cosmostat.org/software/glimpse

  8. Identification of unknown pesticides in fruits using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Imazalil as a case study of quantification.

    Science.gov (United States)

    Picó, Yolanda; la Farré, Marinel; Soler, Carla; Barceló, Damià

    2007-12-28

    Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) is an emerging technique offering more rapid and efficient separation, as well as the possibility to obtain accurate mass measurement and tandem mass spectrometry (MS/MS). This paper deals with the use of UPLC-QqTOF-MS to identify the pesticide residues present in complex pear extracts. Carbendazim, imazalil, and ethoxyquin were successfully identified because of the accurate mass determination of their protonated molecule and their major fragments in the product ion mass spectra. A few plastic and latex additives were also found, most of them probably coming from the packaging transfer to the fruits. The potential of the UPLC-QqTOF-MS and UPLC-QqTOF-MS/MS techniques as a quantification tool is also discussed taking imazalil as example. For quantification, calibration curves were linear over a dynamic range of 2 orders of magnitude, whereas higher calibration ranges are better adjusted to polynomial curves of second and third order. Quantification using different mass windows was also assessed. Accurate quantification required mass windows as wide as 20 mDa, narrower mass windows of 5 mDa provided erroneous quantification, probably because the low ion abundance. The mean recoveries and percentage relative standard deviation (RSD) of 35 determinations for imazalil were 76% (13% RSD) by MS and 77% (14% RSD) by MS/MS. The theoretical limit of detection was 0.4 microg kg(-1), with a validated limit of quantification of 2 microg kg(-1). The quantitative data obtained using UPLC-QqTOF-MS were compared with those obtained using conventional liquid chromatography (LC)-MS/MS with a triple quadrupole (QqQ). It was concluded that UPLC-QqTOF-MS might become a powerful analytical tool for both, unknown's identification and quantification of target pesticides.

  9. Evaluation of a High Resolving Power Time-of-Flight Mass Spectrometer for Drug Analysis in Terms of Resolving Power and Acquisition Rate

    Science.gov (United States)

    Pelander, Anna; Decker, Petra; Baessmann, Carsten; Ojanperä, Ilkka

    2011-02-01

    Liquid chromatography time-of-flight mass spectrometry (LC-TOFMS) is applied increasingly to various fields of small molecule analysis. The moderate resolving power (RP) of standard TOFMS instruments poses a risk of false negative results when complex biological matrices are to be analyzed. In this study, the performance of a high resolving power TOFMS instrument (maXis by Bruker Daltonik, Bremen, Germany) was evaluated for drug analysis. By flow injection analysis of critical drug mixtures, including a total of 17 compounds with nominal masses of 212-415 Da and with mass differences of 8.8-23.5 mDa, RP varied from 34,400 to 51,900 (FWHM). The effect of acquisition rate on RP, mass accuracy, and isotopic pattern fit was studied by applying 1, 2, 5, 10, and 20 Hz acquisition rates in a 16 min gradient elution LC separation. All three variables were independent of the acquisition rate, with an average mass accuracy and isotopic pattern fit factor (mSigma) of 0.33 ppm and 5.9, respectively. The average relative standard deviation of RP was 1.8%, showing high repeatability. The performance was tested further with authentic urine extracts containing a co-eluting compound pair with a nominal mass of 296 Da and an 11.2 mDa mass difference. The authentic sample components were readily resolved and correctly identified by the automated data analysis. The average RP, mass accuracy, and isotopic pattern fit were 36,600, 0.9 ppm, and 7.3 mSigma, respectively.

  10. Chemometric and multivariate statistical analysis of time-of-flight secondary ion mass spectrometry spectra from complex Cu-Fe sulfides.

    Science.gov (United States)

    Kalegowda, Yogesh; Harmer, Sarah L

    2012-03-20

    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra of mineral samples are complex, comprised of large mass ranges and many peaks. Consequently, characterization and classification analysis of these systems is challenging. In this study, different chemometric and statistical data evaluation methods, based on monolayer sensitive TOF-SIMS data, have been tested for the characterization and classification of copper-iron sulfide minerals (chalcopyrite, chalcocite, bornite, and pyrite) at different flotation pulp conditions (feed, conditioned feed, and Eh modified). The complex mass spectral data sets were analyzed using the following chemometric and statistical techniques: principal component analysis (PCA); principal component-discriminant functional analysis (PC-DFA); soft independent modeling of class analogy (SIMCA); and k-Nearest Neighbor (k-NN) classification. PCA was found to be an important first step in multivariate analysis, providing insight into both the relative grouping of samples and the elemental/molecular basis for those groupings. For samples exposed to oxidative conditions (at Eh ~430 mV), each technique (PCA, PC-DFA, SIMCA, and k-NN) was found to produce excellent classification. For samples at reductive conditions (at Eh ~ -200 mV SHE), k-NN and SIMCA produced the most accurate classification. Phase identification of particles that contain the same elements but a different crystal structure in a mixed multimetal mineral system has been achieved.

  11. Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

    Science.gov (United States)

    Dong, Meirong; Oropeza, Dayana; Chirinos, José; González, Jhanis J.; Lu, Jidong; Mao, Xianglei; Russo, Richard E.

    2015-07-01

    The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal.

  12. Extending the laserspray ionization concept to produce highly charged ions at high vacuum on a time-of-flight mass analyzer.

    Science.gov (United States)

    Trimpin, Sarah; Ren, Yue; Wang, Beixi; Lietz, Christopher B; Richards, Alicia L; Marshall, Darrell D; Inutan, Ellen D

    2011-07-15

    A new matrix compound, 2-nitrophloroglucinol, is reported which not only produces highly charged ions similar to electrospray ionization (ESI) under atmospheric pressure (AP) and intermediate pressure (IP) laserspray ionization (LSI) conditions but also the most highly charged ions so far observed for small proteins in mass spectrometry (MS) under high vacuum (HV) conditions. This new matrix extends the compounds that can successfully be employed as matrixes with LSI, as demonstrated on an LTQ Velos (Thermo) at AP, a matrix-assisted laser desorption/ionization (MALDI)-ion mobility spectrometry (IMS) time-of-flight (TOF) SYNAPT G2 (Waters) at IP, and MALDI-TOF Ultraflex, UltrafleXtreme, and Autoflex Speed (Bruker) mass spectrometers at HV. Measurements show that stable multiple charged molecular ions of proteins are formed under all pressure conditions indicating softer ionization than MALDI, which suffers a high degree of metastable fragmentation when multiply charged ions are produced. An important analytical advantage of this new LSI matrix are the potential for high sensitivity equivalent or better than AP-LSI and vacuum MALDI and the potential for enhanced mass selected fragmentation of the abundant highly charged protein ions. A second new LSI matrix, 4,6-dinitropyrogallol, produces abundant multiply charged ions at AP but not under HV conditions. The differences in these similar compounds ability to produce multiply charged ions under HV conditions is believed to be related to their relative ability to evaporate from charged matrix/analyte clusters.

  13. Isotopically-selective two-photon ionization of 12C- and 13C-benzene and hexadeuterobenzene in a time-of-flight mass spectrometer

    Science.gov (United States)

    de La Cruz, A.; Ortiz, M.; Cabrera, J. A.; Campos, J.

    1994-04-01

    In this work the 610 band spectra for 12C6H6, 12C6D6, 13C12C5H6 and 13C12C5D6 isotopically-substituted benzenes are reported. Spectra of deuterated species are given for the first time. These molecular spectra can be employed to test the technical performances of REMPI-TOFMS systems. The experimental method was laser-induced two-photon ionization of molecules cooled in a He supersonic beam followed by time-of-flight mass spectrometry. A splitting of the 610 band appears when a 13C atom is present in the benzene-ring, favoring the isotope selectivity. In the present experiment a complete mass discrimination has been accomplished by using appropriate electronic circuits. A proportional counter has been used to obtain the corresponding spectra of the molecules at 300 K. The device is very useful to tune the laser wavelength to resonance in this kind of mass spectrometry experiment.

  14. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS: A New Tool for the Analysis of Toxicological Effects on Single Cell Level

    Directory of Open Access Journals (Sweden)

    Harald Jungnickel

    2016-02-01

    Full Text Available Single cell imaging mass spectrometry opens up a complete new perspective for strategies in toxicological risk assessment and drug discovery. In particular, time-of-flight secondary ion mass spectrometry (ToF-SIMS with its high spatial and depth resolution is becoming part of the imaging mass spectrometry toolbox used for single cell analysis. Recent instrumentation advancements in combination with newly developed cluster ion guns allow 3-dimensional reconstruction of single cells together with a spatially resolved compound location and quantification on nanoscale depth level. The exact location and quantification of a single compound or even of a set of compounds is no longer restricted to the two dimensional space within single cells, but is available for voxels, a cube-sized 3-dimensional space, rather than pixels. The information gathered from one voxel is further analysed using multivariate statistical methodology like maximum autocorrelation factors to co-locate the compounds of interest within intracellular organelles like nucleus, mitochondria or golgi apparatus. Furthermore, the cell membrane may be resolved, including adhering compounds and potential changes of the lipid patterns. The generated information can be used further for a first evaluation of intracellular target specifity of new drug candidates or for the toxicological risk assessment of environmental chemicals and their intracellular metabolites. Additionally, single cell lipidomics and metabolomics enable for the first time an in-depth understanding of the activation or inhibition of cellular biosynthesis and signalling pathways.

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

    Science.gov (United States)

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

    2016-08-01

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

  16. [Screening method for 29 forbidden or limited synthetic pigments in cheese by liquid chromatography/quadrupole time-of-flight mass spectrometry].

    Science.gov (United States)

    Zhao, Yansheng; Yang, Minli; Zhang, Feng; Feng, Feng; Chu, Xiaogang; Dong, Ying

    2011-07-01

    A screening method for 29 forbidden or limited synthetic pigments in cheese samples was established by liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/Q-TOF MS). The pigments were extracted by n-hexane/water (3:1, v/v). After extraction, the n-hexane extract, water extract and residue, were obtained. The n-hexane extract was then cleaned-up by gel permeation chromatography (GPC). The water extract was extracted by acetonitrile, and the residue by ammonia water/methanol (1:99, v/v). The results showed that the 29 synthetic pigments with a wide range of polarities were extracted effectively with the recoveries between 70% and 95%, and matched well by Q-TOF MS precision mass searching to the mass spectral library with matching scores between 59. 66 and 99. 47. The quantitative analysis of the 29 pigments was carried out by Target MS/MS. The limits of detection (LODs) for 8 Sudan dyes were 0.4-2.5 micro/kg while for 21 water-soluble synthetic pigments were 20-80 microg/kg. The screening method is suitable for a wide range of synthetic pigments, and can be applied to food samples with proteins and fat in matrix.

  17. [Rapid screening and confirmation of non-target pigment in Chinese softshell turtle by liquid chromatography coupled to time of flight mass spectrometry].

    Science.gov (United States)

    Li, Shiyan; Wang, Yang; Zhou, Fan; Zheng, Chongying; Zhang, Haiqi; He, Zhongyang; He, Xin

    2015-12-01

    A method of non-target pigment screening in Chinese softshell turtle has been established by using liquid chromatography coupled to time of flight mass spectrometry (LC-Q-TOF MS). After being purified by a simple acetonitrile extraction work, the non-target pigment in 20 Chinese softshell turtle samples was detected by liquid chromatography-photodiode array detection (LC-DAD). The S7 sample, which has a strong spectral response, was chosen to extract the mass spectrometry information of the non-target pigment on different gradient elution conditions. In order to get the characteristic molecular mass ion (564.397 73 Da and 564.395 61 Da) of the non-target pigment, qualitative spectral full scan with negative sample was used. The molecular formula generation data and the literature information prompted speculation that the non-target pigment was canthaxanthin with the formula of C40H52O2. By comparing the canthaxanthin standard material MS/MS information, the result was confirmed accurate. A strategy of LC-Q-TOF MS method for the qualitative analysis of unknown compounds is discussed, and the results indicated that the described method can be effectively applied to qualitative analysis for non-target pigment in Chinese softshell turtle.

  18. Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Bobeldijk, I; Vissers, J P; Kearney, G; Major, H; Van Leerdam, J A

    2001-09-21

    In order to assess and maintain the quality of surface waters, target compound monitoring is often not sufficient. Many unknown micro-contaminants are present in water, originating in municipal, industrial or agricultural effluents. Some of these might pose a risk to drinking water production and consequently to human health. The possibilities of screening surface water and identification of these non-target water pollutants with modern data acquisition possibilities of hybrid quadrupole-orthogonal acceleration time of flight mass spectrometers (Q-TOF), such as data-dependent MS to MS/MS switching were investigated. Using model compounds, a procedure for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening of water extracts was developed, enabling the detection and identification of compounds at levels < or = 0.25 microg/l in surface water. Based on the accurate mass the elemental compositions for the precursor and product ions are calculated. The calculated chemical formulae are searched against the Merck index, the NIST library, an own database containing about 2,500 water pollutants (pesticides and other contaminants) as well as a CI-CID library containing tandem MS spectra of about 100 water contaminants. The developed approach was applied for the identification of unknown compounds, present in native surface water extract. For three of these compounds, structures were proposed. Confirmation of the proposed structures with standards was beyond the scope of this study.

  19. Evaluation of a Semiquantitative Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Method for Rapid Antimicrobial Susceptibility Testing of Positive Blood Cultures.

    Science.gov (United States)

    Jung, Jette S; Hamacher, Christina; Gross, Birgit; Sparbier, Katrin; Lange, Christoph; Kostrzewa, Markus; Schubert, Sören

    2016-11-01

    With the increasing prevalence of multidrug-resistant Gram-negative bacteria, rapid identification of the pathogen and its individual antibiotic resistance is crucial to ensure adequate antiinfective treatment at the earliest time point. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry for the identification of bacteria directly from the blood culture bottle has been widely established; however, there is still an urgent need for new methods that permit rapid resistance testing. Recently, a semiquantitative MALDI-TOF mass spectrometry-based method for the prediction of antibiotic resistance was described. We evaluated this method for detecting nonsusceptibility against two β-lactam and two non-β-lactam antibiotics. A collection of 30 spiked blood cultures was tested for nonsusceptibility against gentamicin and ciprofloxacin. Furthermore, 99 patient-derived blood cultures were tested for nonsusceptibility against cefotaxime, piperacillin-tazobactam, and ciprofloxacin in parallel with MALDI-TOF mass spectrometry identification from the blood culture fluid. The assay correctly classified all isolates tested for nonsusceptibility against gentamicin and cefotaxime. One misclassification for ciprofloxacin nonsusceptibility and five misclassifications for piperacillin-tazobactam nonsusceptibility occurred. Identification of the bacterium and prediction of nonsusceptibility was possible within approximately 4 h.

  20. Analytical detection of explosives and illicit, prescribed and designer drugs using proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Bishu; Petersson, Fredrik; Juerschik, Simone [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Sulzer, Philipp; Jordan, Alfons [IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria); Maerk, Tilmann D. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria); Watts, Peter; Mayhew, Chris A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 4TT (United Kingdom)

    2011-07-01

    This work demonstrates the extremely favorable features of Proton Transfer Reaction Time-of-flight Mass Spectrometry (PTR-TOF-MS) for the detection and identification of solid explosives, chemical warfare agent simulants and illicit, prescribed and designer drugs in real time. Here, we report the use of PTR-TOF, for the detection of explosives (e.g., trinitrotoluene, trinitrobenzene) and illicit, prescribed and designer drugs (e.g., ecstasy, morphine, heroin, ethcathinone, 2C-D). For all substances, the protonated parent ion (as we used H{sub 3}O{sup +} as a reagent ion) could be detected, providing a high level of confidence in their identification since the high mass resolution allows compounds having the same nominal mass to be separated. We varied the E/N from 90 to 220 T{sub d} (1 T{sub d}=10{sup -17} Vcm{sup -1}). This allowed us to study fragmentation pathways as a function of E/N (reduced electric field). For a few compounds rather unusual E/N dependencies were also discovered.

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

    Science.gov (United States)

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

    2015-01-01

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

  2. Study of bis(bibenzyls) in bryophytes using electron ionization time-of-flight and electrospray ionization triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Guo, Huaifang; Xing, Jie; Xie, Chunfeng; Qu, Jianbo; Gao, Yanhui; Lou, Hongxiang

    2007-01-01

    A detailed analysis of mass spectra generated from bis(bibenzyl) compounds in bryophytes under electron ionization time-of-flight (EI-TOF) and electrospray ionization triple-quadrupole (ESI-TQ) mass spectrometry conditions is reported. Proposed structures of the fragment ions were obtained by tracking the functional groups of 15 bis(bibenzyls), the structures of which are similar except for some alkoxyl substituents and linkage sites of biphenyl ether bonds. The elucidation was aided by the use of accurate mass measurements. Attempts have been made to provide rational pathways for the formation of these fragment ions, and a generalized fragmentation mechanism is proposed. The bis(bibenzyls) mentioned in this study include three types according to their structure characteristics, i.e. one biphenyl ether bond (A-type), two biphenyl ether bonds (B-type), one biphenyl ether and one biphenyl bond (C-type). The three types display different EI-MS and ESI-MS/MS product profiles, by which the bis(bibenzyl) type and the number of alkoxyl substituents can be identified. Isomers of bis(bibenzyls) can be differentiated to some extent, while the linkage sites of biphenyl ether bonds are difficult to identify. The structure-fragmentation relationships will facilitate the characterization of other bis(bibenzyls) and this will be of value for the high-throughput screening of novel bis(bibenzyls) in bryophytes.

  3. Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Meirong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Oropeza, Dayana [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Chirinos, José [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1041a (Venezuela, Bolivarian Republic of); González, Jhanis J. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Lu, Jidong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Mao, Xianglei [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Russo, Richard E., E-mail: RERusso@lbl.gov [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)

    2015-07-01

    The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal. - Highlights: • Tandem LIBS LA-ICP-MS • Simultaneous determination of major and minor elements and trace elements in the coal samples. • Extended Dynamic Range • Correlation between LIBS with LA-ICP-MS demonstrated improved the accuracy and precision for quantitative analysis of coal.

  4. Characterization of Dissolved Organic Matter in River Water by Conventional Methods and Direct Sample Analysis-Time of Flight-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    T. Garrido Reyes

    2016-01-01

    Full Text Available The dissolved organic matter in surface waters is composed of fractions of different molecular weight and polarity, characteristics that determine their capacity for complexing different types of pollutants and their environmental impact. In this study, the dissolved organic matter in the surface water of the Bio-Bio River (Central Region of Chile was characterized chemically and spectroscopically after fractionating by molecular weight and polarity. The technique of direct sample analysis-time of flight-mass spectrometry (DSA-TOF-MS was used to obtain more information on the composition of dissolved organic matter. It is concluded that dissolved organic matter found in the water of the river from the site of minor human impact (Rucalhue has a predominantly natural origin, with a high content of aromatic carbon, in contrast to dissolved organic matter found in the waters of the sites that have higher human impact (Laja and Concepción, characterized by a greater molecular size and higher organic carbon content. These results are consistent with those obtained from DSA-TOF-MS, where higher correlation was observed between the mass spectrum of the standard commercial humic acid and dissolved organic matter found in the sectors of Laja and Concepción, unlike the spectrum mass of lignin which is more like dissolved organic matter found in the sector Rucalhue.

  5. Correlations in the chemical composition of rural background atmospheric aerosol in the UK determined in real time using time-of-flight mass spectrometry.

    Science.gov (United States)

    Beddows, David C S; Donovan, Robert J; Harrison, Roy M; Heal, Mathew R; Kinnersley, Robert P; King, Martin D; Nicholson, David H; Thompson, Katherine C

    2004-02-01

    An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51,980 particles, in the size range 0.3-7.4 microm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d 2.5 microm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium.

  6. Performance evaluation of a miniature laser ablation time-of-flight mass spectrometer designed for in situ investigations in planetary space research.

    Science.gov (United States)

    Riedo, A; Bieler, A; Neuland, M; Tulej, M; Wurz, P

    2013-01-01

    Key performance features of a miniature laser ablation time-of-flight mass spectrometer designed for in situ investigations of the chemical composition of planetary surfaces are presented. This mass spectrometer is well suited for elemental and isotopic analysis of raw solid materials with high sensitivity and high spatial resolution. In this study, ultraviolet laser radiation with irradiances suitable for ablation (laser ablation studies at infrared wavelengths, several improvements to the experimental setup have been made, which allow accurate control over the experimental conditions and good reproducibility of measurements. Current performance evaluations indicate significant improvements to several instrumental figures of merit. Calibration of the mass scale is performed within a mass accuracy (Δm/m) in the range of 100 ppm, and a typical mass resolution (m/Δm) ~600 is achieved at the lead mass peaks. At lower laser irradiances, the mass resolution is better, about (m/Δm) ~900 for lead, and limited by the laser pulse duration of 3 ns. The effective dynamic range of the instrument was enhanced from about 6 decades determined in previous study up to more than 8 decades at present. Current studies show high sensitivity in detection of both metallic and non-metallic elements. Their abundance down to tens of ppb can be measured together with their isotopic patterns. Due to strict control of the experimental parameters, e.g. laser characteristics, ion-optical parameters and sample position, by computer control, measurements can be performed with high reproducibility.

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

    Science.gov (United States)

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

    2016-07-01

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

  8. A Computational Drug Metabolite Detection Using the Stable Isotopic Mass-Shift Filtering with High Resolution Mass Spectrometry in Pioglitazone and Flurbiprofen

    Directory of Open Access Journals (Sweden)

    Yohei Miyamoto

    2013-09-01

    Full Text Available The identification of metabolites in drug discovery is important. At present, radioisotopes and mass spectrometry are both widely used. However, rapid and comprehensive identification is still laborious and difficult. In this study, we developed new analytical software and employed a stable isotope as a tool to identify drug metabolites using mass spectrometry. A deuterium-labeled compound and non-labeled compound were both metabolized in human liver microsomes and analyzed by liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS. We computationally aligned two different MS data sets and filtered ions having a specific mass-shift equal to masses of labeled isotopes between those data using our own software. For pioglitazone and flurbiprofen, eight and four metabolites, respectively, were identified with calculations of mass and formulas and chemical structural fragmentation analysis. With high resolution MS, the approach became more accurate. The approach detected two unexpected metabolites in pioglitazone, i.e., the hydroxypropanamide form and the aldehyde hydrolysis form, which other approaches such as metabolite-biotransformation list matching and mass defect filtering could not detect. We demonstrated that the approach using computational alignment and stable isotopic mass-shift filtering has the ability to identify drug metabolites and is useful in drug discovery.

  9. Aqueous-phase photooxidation of levoglucosan - a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)

    Science.gov (United States)

    Zhao, R.; Mungall, E. L.; Lee, A. K. Y.; Aljawhary, D.; Abbatt, J. P. D.

    2014-09-01

    Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (-2H) were observed among the products detected, providing useful information for determining potential reaction mechanisms and sequences. Additionally, bond-scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double-bond-equivalence-to-carbon ratio (DBE/#C). The trajectory of LG photooxidation on this plot suggests formation of polycarbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M-1 s-1. By coupling an aerosol mass spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol ToF-CIMS. The trajectory of LG photooxidation on a f44-f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the

  10. Aqueous-phase photooxidation of levoglucosan - a mechanistic study using Aerosol Time of Flight Chemical Ionization Mass Spectrometry (Aerosol-ToF-CIMS)

    Science.gov (United States)

    Zhao, R.; Mungall, E. L.; Lee, A. K. Y.; Aljawhary, D.; Abbatt, J. P. D.

    2014-04-01

    Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase, despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by Aerosol Time of Flight Chemical Ionization Mass Spectrometry (Aerosol-ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol-ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (-2H) were observed among the products detected, providing useful information to determine potential reaction mechanisms and sequences. As well, bond scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double bond equivalence to carbon ratio (DBE / #C). The trajectory of LG photooxidation on this plot suggests formation of poly-carbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M-1 s-1. By coupling an Aerosol Mass Spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol-ToF-CIMS. The trajectory of LG photooxidation on a f44-f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the ambient

  11. Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

    2015-06-01

    A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule.

  12. Detection of bacteria from biological mixtures using immunomagnetic separation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    Science.gov (United States)

    Madonna, A.J.; Basile, F.; Furlong, E.; Voorhees, K.J.

    2001-01-01

    A rapid method for identifying specific bacteria from complex biological mixtures using immunomagnetic separation coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been developed. The technique employs commercially available magnetic beads coated with polycolonal antibodies raised against specific bacteria and whole cell analysis by MALDI-MS. A suspension of a bacterial mixture is mixed with the immunomagnetic beads specific for the target microorganism. After a short incubation period (20 mins) the bacteria captured by the beads are washed, resuspended in deionized H2O and directly applied onto a MALDI probe. Liquid suspensions containing bacterial mixtures can be screened within 1 h total analysis time. Positive tests result in the production of a fingerprint mass spectrum primarily consisting of protein biomarkers characteristic of the targeted microorganism. Using this procedure, Salmonella choleraesuis was isolated and detected from standard bacterial mixtures and spiked samples of river water, human urine, and chicken blood. Copyright ?? 2001 John Wiley & Sons, Ltd.

  13. Evaluation of the Andromas matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of aerobically growing Gram-positive bacilli.

    Science.gov (United States)

    Farfour, E; Leto, J; Barritault, M; Barberis, C; Meyer, J; Dauphin, B; Le Guern, A-S; Leflèche, A; Badell, E; Guiso, N; Leclercq, A; Le Monnier, A; Lecuit, M; Rodriguez-Nava, V; Bergeron, E; Raymond, J; Vimont, S; Bille, E; Carbonnelle, E; Guet-Revillet, H; Lécuyer, H; Beretti, J-L; Vay, C; Berche, P; Ferroni, A; Nassif, X; Join-Lambert, O

    2012-08-01

    Matrix-associated laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid and simple microbial identification method. Previous reports using the Biotyper system suggested that this technique requires a preliminary extraction step to identify Gram-positive rods (GPRs), a technical issue that may limit the routine use of this technique to identify pathogenic GPRs in the clinical setting. We tested the accuracy of the MALDI-TOF MS Andromas strategy to identify a set of 659 GPR isolates representing 16 bacterial genera and 72 species by the direct colony method. This bacterial collection included 40 C. diphtheriae, 13 C. pseudotuberculosis, 19 C. ulcerans, and 270 other Corynebacterium isolates, 32 L. monocytogenes and 24 other Listeria isolates, 46 Nocardia, 75 Actinomyces, 18 Actinobaculum, 11 Propionibacterium acnes, 18 Propionibacterium avidum, 30 Lactobacillus, 21 Bacillus, 2 Rhodococcus equi, 2 Erysipelothrix rhusiopathiae, and 38 other GPR isolates, all identified by reference techniques. Totals of 98.5% and 1.2% of non-Listeria GPR isolates were identified to the species or genus level, respectively. Except for L. grayi isolates that were identified to the species level, all other Listeria isolates were identified to the genus level because of highly similar spectra. These data demonstrate that rapid identification of pathogenic GPRs can be obtained without an extraction step by MALDI-TOF mass spectrometry.

  14. Applications of whole-cell matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry in systematic microbiology.

    Science.gov (United States)

    Welker, Martin; Moore, Edward R B

    2011-02-01

    In the last few years matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been increasingly studied and applied for the identification and typing of microorganisms. Very recently, MALDI-TOF MS has been introduced in clinical routine microbiological diagnostics with marked success, which is remarkable considering that not long ago the technology was generally seen as being far from practical application. The identification of microbial isolates by whole-cell mass spectrometry (WC-MS) is being recognized as one of the latest tools forging a revolution in microbial diagnostics, with the potential of bringing to an end many of the time-consuming and man-power-intensive identification procedures that have been used for decades. Apart from applications of WC-MS in clinical diagnostics, other fields of microbiology also have adopted the technology with success. In this article, an over-view of the principles of MALDI-TOF MS and WC-MS is presented, highlighting the characteristics of the technology that allow its utilization for systematic microbiology.

  15. Dispersive liquid-liquid microextraction for the determination of flavonoid aglycone compounds in honey using liquid chromatography with diode array detection and time-of-flight mass spectrometry.

    Science.gov (United States)

    Campillo, Natalia; Viñas, Pilar; Férez-Melgarejo, Gema; Hernández-Córdoba, Manuel

    2015-01-01

    A rapid approach for the determination of eight flavonoid aglycone compounds, baicalein, hesperitin, fisetin, naringenin, chrysin, myricetin, quercetin and kaempferol, in honey samples and related products has been optimized and validated. The enriched extracts obtained by dispersive liquid-liquid microextraction (DLLME) were analyzed by liquid chromatography with diode array detection coupled to electrospray ionization and time-of-flight mass spectrometry (LC-DAD-ESI-ToFMS). For DLLME, using acetonitrile and chloroform as disperser and extractant solvents, respectively, a Taguchi experimental method was applied to find the optimal combination of following six factors: disperser and extractant solvent volumes, sodium chloride concentration, pH of the aqueous phase, honey mass and centrifugation time. The sedimented organic phase obtained after centrifugation was evaporated, reconstituted in acetonitrile and submitted to LC. The matrix effect was evaluated, and it was concluded that sample quantification can be carried out against aqueous external standards when using DAD and by matrix-matched calibration in the case of ToFMS. Detection limits in the ranges of 0.4-4 and 0.01-0.5 ng g(-1) were obtained for DAD and ToFMS, respectively. Satisfactory recovery values between 80 and 111% were obtained for three spiked samples. Honeys and related products were analyzed and flavonoids were found within a wide range.

  16. Characterization of Staphylococcus aureus Isolated from Clinical Specimens by Matrix Assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    WANG Ye Ru; CHEN Qian; CUI Sheng Hui; LI Feng Qin

    2013-01-01

    Objective To develop a matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approach to identify Staphylococcus aureus (S. aureus) and differentiate methicillin-resistant S. aureus (MRSA) from methicillin-sensitive S. aureus (MSSA). Methods A total of 100 S. aureus strains isolated from clinical specimens and farm workers were collected and analyzed by MALDI-TOF-MS. And data obtained were interpreted with biotyper software. Results Ninety-two strains were identified by MALDI-TOF-MS as S. aureus at a level of secure genus and probable species, and 4 strains were identified at probable genus after their cultivation, spectral collection and data preprocessing. One strain was identified as S. aureus with lower score. It was revealed that identification of S. aureus by MALDI-TOF-MS was highly correlated with typing by biochemical and serological methods with an accuracy as high as 97%. The biotyper cluster analysis showed that 100 isolates were divided into 2 types at the distance level of 400. Higher peak intensity in the mass of both 3784 Da and 5700 Da was observed in MRSA, whereas that was absent from MSSA. Conclusion MALDI-TOF-MS is considered as a simple, rapid and highly reproducible technique with high-throughput and accuracy for the identification of S. aureus and it can reliably differentiate MRSA from MSSA.

  17. Advanced ultra-performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometric methods for simultaneous screening and quantification of triterpenoids in Poria cocos.

    Science.gov (United States)

    Xia, Bing; Zhou, Yan; Tan, Hong Sheng; Ding, Li Sheng; Xu, Hong Xi

    2014-01-01

    A sensitive, precise and accurate method was developed to screen and quantify triterpenoids based on ultra-performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (UPLC-PDA-QTOF-MS). An exact neutral loss scan of 62.0004 Da (CH2O3) was used to selectively detect triterpenoids in Poria cocos, followed by a survey scan for exact masses of precursor and fragment ions of these triterpenoids. The developed method was applied to quantify seven major triterpenoids in 40 P. cocos samples of different origins within 18 min, and a total of 31 triterpenoids were unequivocally or tentatively identified. Principal component analysis of these samples showed a clear separation of three groups, and ten triterpenoids play key roles in differentiating these samples were obtained from the OPLS-DA variable influence on projection (VIP) plot and then unequivocally or tentatively identified. The developed method can be applied for rapid bitterness evaluation, quality control and authenticity establishment of P. cocos.

  18. Rapid detection of high-risk Enterococcus faecium clones by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Freitas, Ana R; Sousa, Clara; Novais, Carla; Silva, Liliana; Ramos, Helena; Coque, Teresa M; Lopes, João; Peixe, Luísa

    2017-04-01

    We aimed to explore the potential of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for early identification of dominant Enterococcus faecium (Efm) clones involved in human infections. Well-characterized Efm isolates (n=77), analyzed by pulsed-field gel electrophoresis and multilocus sequence typing(eBURST and BAPS [Bayesian analysis of population structure] algorithms), and belonging to different hospital (n=53) and community (n=24) phylogenomic groups, were tested. Mass spectra (Bruker) were analyzed by visual inspection and different chemometric tools. Discrimination between groups comprising isolates commonly found in hospitals (BAPS 2.1a, 3.3a1, 3.3a2) and community (BAPS 2.1b and 3.2) was achieved with >99% accuracy, while identification of sequence types belonging to different BAPS subgroups was associated with >95% correct predictions. Our work is a proof of concept with regard to the suitability of MALDI-TOF MS in the identification of high-risk Efm clones. Further studies including strains from a wider variety of clones and sources will strengthen the potential of the workflow here described.

  19. Localization of ginsenosides in Panax ginseng with different age by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry imaging.

    Science.gov (United States)

    Bai, Hangrui; Wang, Shujuan; Liu, Jianjun; Gao, Dan; Jiang, Yuyang; Liu, Hongxia; Cai, Zongwei

    2016-07-15

    The root of Panax ginseng C.A. Mey. (P. ginseng) is one of the most popular traditional Chinese medicines, with ginsenosides as its main bioactive components. Because different ginsenosides have varied pharmacological effects, extraction and separation of ginsenosides are usually required for the investigation of pharmacological effects of different ginsenosides. However, the contents of ginsenosides vary with the ages and tissues of P. ginseng root. In this research, an efficient method to explore the distribution of ginsenosides and differentiate P. ginseng roots with different ages was developed based on matrix assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-TOF-MSI). After a simple sample preparation, there were 18 peaks corresponding to 31 ginsenosides with distinct localization in the mass range of m/z 700-1400 identified by MALDI-TOF-MSI and MALDI-TOF-MS/MS. All the three types of ginsenosides were successfully detected and visualized in images, which could be correlated with anatomical features. The P. ginseng at the ages of 2, 4 and 6 could be differentiated finely through the principal component analysis of data collected from the cork based on the ion images but not data from the whole tissue. The experimental result implies that the established method for the direct analysis of metabolites in plant tissues has high potential for the rapid identification of metabolites and analysis of their localizations in medicinal herbs. Furthermore, this technique also provides valuable information for the component-specific extraction and pharmacological research of herbs.

  20. Tuneable microsecond-pulsed glow discharge design for the simultaneous acquisition of elemental and molecular chemical information using a time-of-flight mass spectrometer.

    Science.gov (United States)

    Solà-Vázquez, Auristela; Martín, Antonio; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2009-04-01

    A microsecond-pulsed direct current glow discharge (GD) was interfaced and synchronized to a time-of-flight mass spectrometer MS(TOF) for time-gated generation and detection of elemental, structural, and molecular ions. In this way, sequential collection of the mass spectra at different temporal regimes occurring during the GD pulse cycle is allowed. The capabilities of this setup were explored using bromochloromethane as model analyte. A simple GD chamber, developed in our laboratory and characterized by a low plasma volume minimizing dilution of the sample but showing great robustness to the entrance of organic compounds in the microsecond-pulsed plasma, has been used. An exhaustive analytical characterization of the GD-MS(TOF) prototype has been performed. Calibration curves for bromochloromethane observed at the different time regimes of the GD pulse cycle (that is, for elemental, fragment, and molecular ions from the analyte) showed very good linearity for the measurement of the different involved ions, with precisions in the range of 7-13% (relative standard deviation). Actual detection limits obtained for bromochloromethane were in the range of 1-3 microg/L for elements monitoring in the GD pulse "prepeak", in the range of 11-13 microg/L when monitoring analyte fragments in the plateau, and about 238 microg/L when measuring the molecular peak in the afterpeak regime.

  1. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry profiling of trace constituents of condom lubricants in the presence of biological fluids.

    Science.gov (United States)

    Spencer, Sandra E; Kim, Sin Young; Kim, Seoung Bum; Schug, Kevin A

    2011-04-15

    The use of condoms in sexual assault cases has become increasingly common due to the heightened awareness of the use of DNA as evidence in criminal investigations. The ability to identify and differentiate the polymers and additives found in lubricant residues can provide investigators leads and insights as to the perpetrator of a sexual assault. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) is ideal for detecting condom lubricants and additives; the instrument is capable of surveying analytes across a wide mass range and is a preferred technique for the analysis of polymers. Three MALDI-TOF-MS methods directed toward the detection and differentiation of condom and personal lubricant residues, as well as their mixtures with biological fluids, were developed and compared: (a) a sample premixed with aqueous matrix; (b) a sample premixed with an ionic liquid matrix; and (c) a layering method that incorporates a cationization reagent. Of the three, the layered method that utilized sodium chloride as a cationization reagent showed the best sensitivity and selectivity. This method allowed for the segregation of the various lubricant formulas into a discrete number of groups. Infrared spectroscopy was used to support and clarify the MALDI data. Principal component analysis was used to further demonstrate the ability of this method to segregate various lubricant types into a limited number of classes. Additionally, lubricant residues could be detected in the presence of biological fluids down to a fraction of a percent.

  2. Elucidation of the aroma compositions of Zhenjiang aromatic vinegar using comprehensive two dimensional gas chromatography coupled to time-of-flight mass spectrometry and gas chromatography-olfactometry.

    Science.gov (United States)

    Zhou, Zhilei; Liu, Shuangping; Kong, Xiangwei; Ji, Zhongwei; Han, Xiao; Wu, Jianfeng; Mao, Jian

    2017-03-03

    In this work, a method to characterize the aroma compounds of Zhenjiang aromatic vinegar (ZAV) was developed using comprehensive two dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOFMS) and gas chromatography olfactometry (GC-O). The column combination was optimized and good separation was achieved. Structured chromatograms of furans and pyrazines were obtained and discussed. A total of 360 compounds were tentatively identified based on mass spectrum match factors, structured chromatogram and linear retention indices comparison. The most abundant class in number was ketones. A large number of esters, furans and derivatives, aldehydes and alcohols were also detected. The odor-active components were identified by comparison of the reported odor of the identified compounds with the odor of corresponding GC-O region. The odorants of methanethiol, 2-methyl-propanal, 2-methyl-butanal/3-methyl-butanal, octanal, 1-octen-3-one, dimethyl trisulfide, trimethyl-pyrazine, acetic acid, 3-(methylthio)-propanal, furfural, benzeneacetaldehyde, 3-methyl-butanoic acid/2-methyl-butanoic acid and phenethyl acetate were suspected to be the most potent. About half of them were identified as significant aroma constituents in ZAV for the first time. Their contribution to specific sensory attribute of ZAJ was also studied. The results indicated that the presented method is suitable for characterization of ZAV aroma constituents. This study also enriches our knowledge on the components and aroma of ZAV.

  3. Optimization and evaluation of surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry for protein profiling of cerebrospinal fluid

    Directory of Open Access Journals (Sweden)

    Gomez-Mancilla Baltazar

    2006-04-01

    Full Text Available Abstract Cerebrospinal fluid (CSF potentially carries an archive of peptides and small proteins relevant to pathological processes in the central nervous system (CNS and surrounding brain tissue. Proteomics is especially well suited for the discovery of biomarkers of diagnostic potential in CSF for early diagnosis and discrimination of several neurodegenerative diseases. ProteinChip surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS is one such approach which offers a unique platform for high throughput profiling of peptides and small proteins in CSF. In this study, we evaluated methodologies for the retention of CSF proteins m/z we found a high degree of overlap between the tested array surfaces. The combination of CM10 and IMAC30 arrays was sufficient to represent between 80–90% of all assigned peaks when using either sinapinic acid or α-Cyano-4-hydroxycinnamic acid as the energy absorbing matrices. Moreover, arrays processed with SPA consistently showed better peak resolution and higher peak number across all surfaces within the measured mass range. We intend to use CM10 and IMAC30 arrays prepared in sinapinic acid as a fast and cost-effective approach to drive decisions on sample selection prior to more in-depth discovery of diagnostic biomarkers in CSF using alternative but complementary proteomic strategies.

  4. [The research and application of pretreatment method for matrix-assisted laser desorption ionization-time of flight mass spectrometry identification of filamentous fungi].

    Science.gov (United States)

    Huang, Y F; Chang, Z; Bai, J; Zhu, M; Zhang, M X; Wang, M; Zhang, G; Li, X Y; Tong, Y G; Wang, J L; Lu, X X

    2017-08-08

    Objective: To establish and evaluate the feasibility of a pretreatment method for matrix-assisted laser desorption ionization-time of flight mass spectrometry identification of filamentous fungi developed by the laboratory. Methods: Three hundred and eighty strains of filamentous fungi from January 2014 to December 2016 were recovered and cultured on sabouraud dextrose agar (SDA) plate at 28 ℃ to mature state. Meanwhile, the fungi were cultured in liquid sabouraud medium with a vertical rotation method recommended by Bruker and a horizontal vibration method developed by the laboratory until adequate amount of colonies were observed. For the strains cultured with the three methods, protein was extracted with modified magnetic bead-based extraction method for mass spectrum identification. Results: For 380 fungi strains, it took 3-10 d to culture with SDA culture method, and the ratio of identification of the species and genus was 47% and 81%, respectively; it took 5-7 d to culture with vertical rotation method, and the ratio of identification of the species and genus was 76% and 94%, respectively; it took 1-2 d to culture with horizontal vibration method, and the ratio of identification of the species and genus was 96% and 99%, respectively. For the comparison between horizontal vibration method and SDA culture method comparison, the difference was statistically significant (χ(2)=39.026, Pfilamentous fungi, which can be applied in clinic.

  5. A shock tube with a high-repetition-rate time-of-flight mass spectrometer for investigations of complex reaction systems

    Science.gov (United States)

    Dürrstein, Steffen H.; Aghsaee, Mohammad; Jerig, Ludger; Fikri, Mustapha; Schulz, Christof

    2011-08-01

    A conventional membrane-type stainless steel shock tube has been coupled to a high-repetition-rate time-of-flight mass spectrometer (HRR-TOF-MS) to be used to study complex reaction systems such as the formation of pollutants in combustion processes or formation of nanoparticles from metal containing organic compounds. Opposed to other TOF-MS shock tubes, our instrument is equipped with a modular sampling unit that allows to sample with or without a skimmer. The skimmer unit can be mounted or removed in less than 10 min. Thus, it is possible to adjust the sampling procedure, namely, the mass flux into the ionization chamber of the HRR-TOF-MS, to the experimental situation imposed by species-specific ionization cross sections and vapor pressures. The whole sampling section was optimized with respect to a minimal distance between the nozzle tip inside the shock tube and the ion source inside the TOF-MS. The design of the apparatus is presented and the influence of the skimmer on the measured spectra is demonstrated by comparing data from both operation modes for conditions typical for chemical kinetics experiments. The well-studied thermal decomposition of acetylene has been used as a test system to validate the new setup against kinetics mechanisms reported in literature.

  6. Characterization of metabolites in rats after intravenous administration of salvianolic acid for injection by ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    Miao, Jingzhuo; Sun, Wanyang; Huang, Jingyi; Liu, Xiaolin; Li, Shuming; Han, Xiaoping; Tong, Ling; Sun, Guoxiang

    2016-09-01

    It is an essential requirement to clarify the metabolites of traditional Chinese medicine (TCM) injections, which contain numerous ingredients, to assess their safe and effective use in clinic. Salvianolic acid for injection (SAFI), made from hydrophilic phenolic acids in Salvia miltiorrhiza Bunge, has been widely used for the treatment of cerebrovascular diseases, but information on its metabolites in vivo is still lacking. In the present study, we aimed to holistically characterize the metabolites of the main active ingredients in rat plasma, bile, urine and feces following intravenous administration of SAFI. An ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method was developed. Combining information on retention behaviors, multistage mass spectra and literature data, a total of eight prototypes and 52 metabolites were tentatively characterized. Metabolites originated from rosmarinic acid and salvianolic acid B comprised the majority of identified compounds. Meanwhile, four metabolites derived from salvianolic acid D and five from salvianolic acid B are reported for the first time. This study revealed that methylation, sulfation and glucuronidation were the major metabolic pathways of phenolic acids in SAFI in vivo. Furthermore, the developed UPLC/Q-TOF-MS method could also benefit the metabolic investigation of extracts and preparations in TCM with hydrophilic ingredients. Copyright © 2016 John Wiley & Sons, Ltd.

  7. A shock tube with a high-repetition-rate time-of-flight mass spectrometer for investigations of complex reaction systems.

    Science.gov (United States)

    Dürrstein, Steffen H; Aghsaee, Mohammad; Jerig, Ludger; Fikri, Mustapha; Schulz, Christof

    2011-08-