Science.gov

Sample records for mass spectrometry instrumentation

  1. Instrumentation for mass spectrometry: 1997

    SciTech Connect

    McLuckey, S.A.

    1997-08-01

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

  2. Evolution of Orbitrap Mass Spectrometry Instrumentation

    NASA Astrophysics Data System (ADS)

    Eliuk, Shannon; Makarov, Alexander

    2015-07-01

    We discuss the evolution of OrbitrapTM mass spectrometry (MS) from its birth in the late 1990s to its current role as one of the most prominent techniques for MS. The Orbitrap mass analyzer is the first high-performance mass analyzer that employs trapping of ions in electrostatic fields. Tight integration with the ion injection process enables the high-resolution, mass accuracy, and sensitivity that have become essential for addressing analytical needs in numerous areas of research, as well as in routine analysis. We examine three major families of instruments (related to the LTQ Orbitrap, Q Exactive, and Orbitrap Fusion mass spectrometers) in the context of their historical development over the past ten eventful years. We discuss as well future trends and perspectives of Orbitrap MS. We illustrate the compelling potential of Orbitrap-based mass spectrometers as (ultra) high-resolution platforms, not only for high-end proteomic applications, but also for routine targeted analysis.

  3. 36Cl accelerator mass spectrometry with a bespoke instrument

    NASA Astrophysics Data System (ADS)

    Wilcken, K. M.; Freeman, S. P. H. T.; Schnabel, C.; Binnie, S. A.; Xu, S.; Phillips, R. J.

    2013-01-01

    Cosmogenic 36Cl analysis by accelerator mass spectrometry (AMS) is a valuable environmental and geological sciences research tool. Overcoming the stable nuclide 36S isobar interfering with measurement is challenging, however. Traditionally this has required large accelerators, but following recent technical advances it is now possible with ∼30 MeV ion energies. Consequently 5 MV or even smaller modern bespoke spectrometers are now 36Cl-capable, increasing accessibility and promoting wider and more varied 36Cl use. However, the technical ability to identify 36Cl ions is quite distinct from demonstrated high-performance AMS. Such is the theme of this paper. We present a systematic analysis of the accurate measurement of sample radioisotope relative to the stable chlorine, the normalisation of the measured ratio and correction for remaining 36S interference, all combined with the use of stable-isotope dilution to determine sample Cl concentration to begin with. We conclude by showing that repeated analyses support our claims for routine 3% 36Cl-AMS data. Accordingly, the modest SUERC spectrometer well competes with the performance of larger longer-established instruments, and the results may be quite generic for modern bespoke instruments.

  4. Mass spectrometry and hyphenated instruments in food analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mass spectrometry (MS) has come a long way since the record of the first mass spectra of a simple low molecular weight substance by J.J. Thomson in 1912. Especially over the past decades, MS has been the subject of many developments. Particularly, the hyphenation of MS to gas chromatography (GC) a...

  5. Combining ion mobility spectrometry, mass spectrometry, and photoelectron spectroscopy in a high-transmission instrument.

    PubMed

    Vonderach, Matthias; Ehrler, Oli T; Weis, Patrick; Kappes, Manfred M

    2011-02-01

    We have developed a novel instrument that combines ion mobility spectrometry, mass spectro-metry, and photoelectron spectroscopy. The instrument couples an electrospray ion source, a high-transmission ion mobility cell based on ion funnels, a quadrupole mass filter, and a time-of-flight (magnetic bottle) photoelectron spectrometer operated with a pulsed detachment laser. We show that the instrument can resolve highly structured anion arrival time distributions and at the same time provide corresponding photoelectron spectra-using the DNA oligonucleotide ion [dC(6) - 5H](5-) as a test case. For this multianion we find at least four different, noninterconverting isomers (conformers) simultaneously present in the gas phase at room temperature. For each of these we record well-resolved and remarkably different photoelectron spectra at each of three different detachment laser wavelengths. Two-dimensional ion mobility/electron binding energy plots can be acquired with an automated data collection procedure. We expect that this kind of instrument will significantly improve the capabilities for structure determination of (bio)molecular anions in the gas phase. PMID:21214198

  6. Charge detection mass spectrometry: Instrumentation & applications to viruses

    NASA Astrophysics Data System (ADS)

    Pierson, Elizabeth E.

    For over three decades, electrospray ionization (ESI) has been used to ionize non-covalent complexes and subsequently transfer the intact ion into the gas phase for mass spectrometry (MS) analysis. ESI generates a distribution of multiple charged ions, resulting in an m/z spectrum comprised of a series of peaks, known as a charge state envelope. To obtain mass information, the number of charges for each peak must be deduced. For smaller biological analytes like peptides, the charge states are sufficiently resolved and this process is straightforward. For macromolecular complexes exceeding ~100 kDa, this process is complicated by the broadening and shifting of charge states due to incomplete desolvation, salt adduction, and inherent mass heterogeneity. As the analyte mass approaches the MDa regime, the m/z spectrum is often comprised of a broad distribution of unresolved charge states. In such cases, mass determination is precluded. Charge detection mass spectrometry (CDMS) is an emerging MS technique for determining the masses of heterogeneous, macromolecular complexes. In CDMS, the m/z and z of single ions are measured concurrently so that mass is easily calculated. With this approach, deconvolution of an m/z spectrum is unnecessary. This measurement is carried out by passing macroions through a conductive cylinder. The induced image charge on the cylindrical detector provides information about m/z and z: the m/z is related to its time-of-flight through the detector, and the z is related to the intensity of the image charge. We have applied CDMS to study the self-assembly of virus capsids. Late-stage intermediates in the assembly of hepatitis B virus, a devastating human pathogen, have been identified. This is the first time that such intermediates have been detected and represent a significant advancement towards understanding virus capsid assembly. CDMS has also been used to identify oversized, non-icosahedral polymorphs in the assembly of woodchuck hepatitis

  7. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  8. Mass spectrometry

    SciTech Connect

    Burlingame, A.L.; Baillie, T.A.; Derrick, P.J.

    1986-04-01

    It is the intention of the review to bring together in one source the direction of major developments in mass spectrometry and to illustrate these by citing key contributions from both fundamental and applied research. The Review is intended to provide the reader with a sense of the main currents, their breadth and depth, and probable future directions. It is also intended to provide the reader with a glimpse of the diverse discoveries and results that underpin the eventual development of new methods and instruments - the keys to obtaining new insights in all the physical, chemical, and biological sciences which depend on mass spectrometry at various levels of sophistication. Focal points for future interdisciplinary synergism might be selective quantitative derivatization of large peptides, which would convey properties that direct fragmentation providing specific sequence information, or optimization of LCMS for biooligomer sequencing and mixture analysis, or the perfect way to control or enhance the internal energy of ions of any size, or many others. 1669 references.

  9. High Resolution Mass Spectrometry for future space instrumentation : current development within the French Space Orbitrap Consortium

    NASA Astrophysics Data System (ADS)

    Briois, Christelle; Lebreton, Jean-Pierre; Szopa, Cyril; Thirkell, Laurent; Aradj, Kenzi; Bouabdellah, Abdel; Boukrara, Amirouche; Carrasco, Nathalie; Chalumeau, Gilles; Chapelon, Olivier; Colin, Fabrice; Cottin, Hervé; Engrand, Cécile; Grand, Noel; Kukui, Alexandre; Pennanech, Cyril; Thissen, Roland; Vuitton, Véronique; Zapf, Pascal; Makarov, Alexander

    2014-05-01

    Mass spectrometry has been used for years in space exploration to characterise the chemical composition of solar system bodies and their environment. Because of the harsh constraints imposed to the space probe instruments, their mass resolution is quite limited compared to laboratory instruments, sometimes leading to significant limitations in the treatment of the data collected with this type of instrumentation. Future in situ solar system exploration missions would significantly benefit from High Resolution Mass Spectrometry (HRMS). For a few years, 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) involved in the chemical investigation of solar system bodies formed a Consortium to develop HRMS for future space exploration, based on the use of the Orbitrap technology (C. Briois et al., 2014, to be submitted). This development is carried out in the frame of a Research and Technology (R&T) development programme partly funded by the French Space Agency (CNES). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercialises Orbitrap-based laboratory instruments. The R&T activities are currently concentrating on the core elements of the Orbitrap analyser that are required to reach a sufficient maturity level for allowing design studies of future space instruments. We are indeed pursuing, within international collaborations, the definition of several instrument concepts based on the core elements that are subject of our R&T programme. In this talk, we briefly discuss science applications for future orbitrap-based HRMS space instruments. We highlight present results of our R&T programme.

  10. Standard Reticle Slide To Objectively Evaluate Spatial Resolution and Instrument Performance in Imaging Mass Spectrometry.

    PubMed

    Zubair, Faizan; Prentice, Boone M; Norris, Jeremy L; Laibinis, Paul E; Caprioli, Richard M

    2016-07-19

    Spatial resolution is a key parameter in imaging mass spectrometry (IMS). Aside from being a primary determinant in overall image quality, spatial resolution has important consequences on the acquisition time of the IMS experiment and the resulting file size. Hardware and software modifications during instrumentation development can dramatically affect the spatial resolution achievable using a given imaging mass spectrometer. As such, an accurate and objective method to determine the working spatial resolution is needed to guide instrument development and ensure quality IMS results. We have used lithographic and self-assembly techniques to fabricate a pattern of crystal violet as a standard reticle slide for assessing spatial resolution in matrix-assisted laser desorption/ionization (MALDI) IMS experiments. The reticle is used to evaluate spatial resolution under user-defined instrumental conditions. Edgespread analysis measures the beam diameter for a Gaussian profile and line scans measure an "effective" spatial resolution that is a convolution of beam optics and sampling frequency. The patterned crystal violet reticle was also used to diagnose issues with IMS instrumentation such as intermittent losses of pixel data. PMID:27299987

  11. A resonance photoionization sputtered neutral mass spectrometry instrument for submicron microarea analysis of ULSI devices

    NASA Astrophysics Data System (ADS)

    Shichi, H.; Osabe, S.; Sugaya, M.; Ino, T.; Kakibayashi, H.; Kanehori, K.; Mitsui, Y.

    2003-01-01

    The lateral profile of boron in an actual microdevice was obtained by 3D analysis—using the newly developed resonance photoionization sputtered neutral mass spectrometry (SNMS) instrument—with a detection limit of 10 18 atoms/cm 3. The primary ion beam optical system of the instrument uses a Ga liquid metal ion source. The Ga beam diameter was about 30 nm and the ion beam current was about 60 pA. The analysis time to get the profile was about 40 min. Boron was excited by using one ultraviolet photon (249.7 nm) and by one visible photon (563 nm), and then it was ionized by an infrared photon (1064 nm): the so-called three-color resonance ionization. Lateral diffusion profile of boron in the device after chemical vapor deposition (CVD) including heating the wafer was also obtained. These results mean that this SNMS instrument will enable us to easily determine semiconductor processing conditions.

  12. An adaptable multiple power source for mass spectrometry and other scientific instruments

    NASA Astrophysics Data System (ADS)

    Lin, T.-Y.; Anderson, G. A.; Norheim, R. V.; Prost, S. A.; LaMarche, B. L.; Leach, F. E.; Auberry, K. J.; Smith, R. D.; Koppenaal, D. W.; Robinson, E. W.; Paša-Tolić, L.

    2015-09-01

    An Adaptable Multiple Power Source (AMPS) system has been designed and constructed. The AMPS system can provide up to 16 direct current (DC) (±400 V; 5 mA), 4 radio frequency (RF) (two 500 VPP sinusoidal signals each, 0.5-5 MHz) channels, 2 high voltage sources (±6 kV), and one ˜40 W, 250 °C temperature-regulated heater. The system is controlled by a microcontroller, capable of communicating with its front panel or a computer. It can assign not only pre-saved fixed DC and RF signals but also profiled DC voltages. The AMPS system is capable of driving many mass spectrometry components and ancillary devices and can be adapted to other instrumentation/engineering projects.

  13. An adaptable multiple power source for mass spectrometry and other scientific instruments.

    PubMed

    Lin, T-Y; Anderson, G A; Norheim, R V; Prost, S A; LaMarche, B L; Leach, F E; Auberry, K J; Smith, R D; Koppenaal, D W; Robinson, E W; Paša-Tolić, L

    2015-09-01

    An Adaptable Multiple Power Source (AMPS) system has been designed and constructed. The AMPS system can provide up to 16 direct current (DC) (±400 V; 5 mA), 4 radio frequency (RF) (two 500 VPP sinusoidal signals each, 0.5-5 MHz) channels, 2 high voltage sources (±6 kV), and one ∼40 W, 250 °C temperature-regulated heater. The system is controlled by a microcontroller, capable of communicating with its front panel or a computer. It can assign not only pre-saved fixed DC and RF signals but also profiled DC voltages. The AMPS system is capable of driving many mass spectrometry components and ancillary devices and can be adapted to other instrumentation/engineering projects. PMID:26429459

  14. MASS SPECTROMETRY

    DOEpatents

    Friedman, L.

    1962-01-01

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

  15. Forensic Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Hoffmann, William D.; Jackson, Glen P.

    2015-07-01

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

  16. Forensic Mass Spectrometry.

    PubMed

    Hoffmann, William D; Jackson, Glen P

    2015-01-01

    Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques. PMID:26070716

  17. Mass Spectrometry Theatre: A Model for Big-Screen Instrumental Analysis

    ERIC Educational Resources Information Center

    Allison, John

    2008-01-01

    Teaching lecture or lab courses in instrumental analysis can be a source of frustration since one can only crowd a small number of students around a single instrument, typically leading to round-robin approaches. Round-robin labs can spread students into multiple labs and limit instructor-student interactions. We discuss "Mass Spectrometry…

  18. Ambient ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lebedev, A. T.

    2015-07-01

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

  19. Evolution of instrumentation for the study of gas-phase ion/ion chemistry via mass spectrometry.

    PubMed

    Xia, Yu; McLuckey, Scott A

    2008-02-01

    The scope of gas-phase ion/ion chemistry accessible to mass spectrometry is largely defined by the available tools. Due to the development of novel instrumentation, a wide range of reaction phenomenologies has been noted, many of which have been studied extensively and exploited for analytical applications. This perspective presents the development of mass spectrometry-based instrumentation for the study of the gas-phase ion/ion chemistry in which at least one of the reactants is multiply charged. The instrument evolution is presented within the context of three essential elements required for any ion/ion reaction study: the ionization source(s), the reaction vessel or environment, and the mass analyzer. Ionization source arrangements have included source combinations that allow for reactions between multiply charged ions of one polarity and singly charged ions of opposite polarity, arrangements that enable the study of reactions of multiply charged ions of opposite polarity and, most recently, arrangements that allow for ion formation from more than two ion sources. Gas-phase ion/ion reaction studies have been performed at near atmospheric pressure in flow reactor designs and within electrodynamic ion traps operated in the mTorr range. With ion trap as a reaction vessel, ionization and reaction processes can be independently optimized and ion/ion reactions can be implemented within the context of MSn experiments. Spatial separation of the reaction vessel from the mass analyzer allows for the use of any form of mass analysis in conjunction with ion/ion reactions. Time-of-flight mass analysis, for example, has provided significant improvements in mass analysis figures of merit relative to mass filters and ion traps. PMID:18083527

  20. Evolution of Instrumentation for the Study of Gas-Phase Ion/Ion Chemistry via Mass Spectrometry

    PubMed Central

    Xia, Yu; McLuckey, Scott A.

    2008-01-01

    The scope of gas phase ion/ion chemistry accessible to mass spectrometry is largely defined by the available tools. Due to the development of novel instrumentation, a wide range of reaction phenomenologies have been noted, many of which have been studied extensively and exploited for analytical applications. This perspective presents the development of mass spectrometry-based instrumentation for the study of the gas phase ion/ion chemistry in which at least one of the reactants is multiply-charged. The instrument evolution is presented within the context of three essential elements required for any ion/ion reaction study: the ionization source(s), the reaction vessel or environment, and the mass analyzer. Ionization source arrangements have included source combinations that allow for reactions between multiply charged ions of one polarity and singly charged ions of opposite polarity, arrangements that enable the study of reactions of multiply charged ions of opposite polarity, and most recently, arrangements that allow for ion formation from more than two ion sources. Gas phase ion/ion reaction studies have been performed at near atmospheric pressure in flow reactor designs and within electrodynamic ion traps operated in the mTorr range. With ion trap as a reaction vessel, ionization and reaction processes can be independently optimized and ion/ion reactions can be implemented within the context of MSn experiments. Spatial separation of the reaction vessel from the mass analyzer allows for the use of any form of mass analysis in conjunction with ion/ion reactions. Time-of-flight mass analysis, for example, has provided significant improvements in mass analysis figures of merit relative to mass filters and ion traps. PMID:18083527

  1. MASS SPECTROMETRY

    DOEpatents

    Nier, A.O.C.

    1959-08-25

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

  2. Combined electron and focused ion beam system for improvement of secondary ion yield in secondary ion mass spectrometry instrument

    SciTech Connect

    Ji, L.; Ji, Q.; Leung, K.-N.; Gough, R. A.

    2006-10-16

    Using a combined electron and focused ion beam system to improve performance of secondary ion mass spectrometry instruments has been investigated experimentally. The secondary ion yield for an Al target has been enhanced to about one order of magnitude higher with the postionization induced by the low energy electrons in the combined beam. It can be further improved with the increase of electron beam current. When the combined beam is applied to insulating targets, sample charging is also eliminated. For Teflon targets, the secondary ion signal is increased by more than a factor of 20.

  3. Ion trap mass spectrometry on a comet nucleus: the Ptolemy instrument and the Rosetta space mission.

    PubMed

    Todd, John F J; Barber, Simeon J; Wright, Ian P; Morgan, Geraint H; Morse, Andrew D; Sheridan, Simon; Leese, Mark R; Maynard, Jon; Evans, Suzanne T; Pillinger, Colin T; Drummond, Duncan L; Heys, Samantha C; Huq, S Ejaz; Kent, Barry J; Sawyer, Eric C; Whalley, Martin S; Waltham, Nicholas R

    2007-01-01

    In May 2014, the Rosetta spacecraft is scheduled to rendezvous with the comet Churyumov-Gerasimenko ('67P'). One of the instruments on board the 'Lander' which will descend on to the surface of the comet is a miniaturised GC/MS system that incorporates an ion trap mass spectrometer, specially developed for isotope ratio analysis. This article describes the development and optimisation of the ion trap for this unique application, and presents a summary of the range of pre-programmed experiments that will contribute to the characterisation of the solid and volatile cometary materials. PMID:17154436

  4. An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

    NASA Astrophysics Data System (ADS)

    Obersteiner, F.; Bönisch, H.; Engel, A.

    2016-01-01

    We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

  5. An Adaptable Multiple Power Source for Mass Spectrometry and other Scientific Instruments

    SciTech Connect

    Lin, Tzu-Yung; Anderson, Gordon A.; Norheim, Randolph V.; Prost, Spencer A.; Lamarche, Brian L.; Leach, Franklin E.; Auberry, Kenneth J.; Smith, Richard D.; Koppenaal, David W.; Robinson, Errol W.; Pasa-Tolic, Ljiljana

    2015-09-18

    Power supplies are commonly used in the operation of many types of scientific equipment, including mass spectrometers and ancillary instrumentation. A generic modern mass spectrometer comprises an ionization source, such as electrospray ionization (ESI), ion transfer devices such as ion funnels and multipole ion guides, and ion signal detection apparatus. Very often such platforms include, or are interfaced with ancillary elements in order to manipulate samples before or after ionization. In order to operate such scientific instruments, numerous direct current (DC) channels and radio frequency (RF) signals are required, along with other controls such as temperature regulation. In particular, DC voltages in the range of ±400 V, along with MHz range RF signals with peak-to-peak amplitudes in the hundreds of volts range are commonly used to transfer ionized samples under vacuum. Additionally, an ESI source requires a high voltage (HV) DC source capable of producing several thousand volts and heaters capable of generating temperatures up to 300°C. All of these signals must be properly synchronized and managed in order to carry out ion trapping, accumulation and detection.

  6. Mass spectrometers: instrumentation

    NASA Astrophysics Data System (ADS)

    Cooks, R. G.; Hoke, S. H., II; Morand, K. L.; Lammert, S. A.

    1992-09-01

    Developments in mass spectrometry instrumentation over the past three years are reviewed. The subject is characterized by an enormous diversity of designs, a high degree of competition between different laboratories working with either different or similar techniques and by extremely rapid progress in improving analytical performance. Instruments can be grouped into genealogical charts based on their physical and conceptual interrelationships. This is illustrated using mass analyzers of different types. The time course of development of particular instrumental concepts is illustrated in terms of the s-curves typical of cell growth. Examples are given of instruments which are at the exponential, linear and mature growth stages. The prime examples used are respectively: (i) hybrid instruments designed to study reactive collisions of ions with surfaces: (ii) the Paul ion trap; and (iii) the triple quadrupole mass spectrometer. In the area of ion/surface collisions, reactive collisions such as hydrogen radical abstraction from the surface by the impinging ion are studied. They are shown to depend upon the chemical nature of the surface through the use of experiments which utilize self-assembled monolayers as surfaces. The internal energy deposited during surface-induced dissociation upon collision with different surfaces in a BEEQ instrument is also discussed. Attention is also given to a second area of emerging instrumentation, namely technology which allows mass spectrometers to be used for on-line monitoring of fluid streams. A summary of recent improvements in the performance of the rapidly developing quadrupole ion trap instrument illustrates this stage of instrument development. Improvements in resolution and mass range and their application to the characterization of biomolecules are described. The interaction of theory with experiment is illustrated through the role of simulations of ion motion in the ion trap. It is emphasized that mature instruments play a

  7. Mass spectrometry. [in organic chemistry

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  8. High-Speed MALDI-TOF Imaging Mass Spectrometry: Rapid Ion Image Acquisition and Considerations for Next Generation Instrumentation

    PubMed Central

    Spraggins, Jeffrey M.; Caprioli, Richard M.

    2012-01-01

    A prototype matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometer has been used for high-speed ion image acquisition. The instrument incorporates a Nd:YLF solid state laser capable of pulse repetition rates up to 5 kHz and continuous laser raster sampling for high-throughput data collection. Lipid ion images of a sagittal rat brain tissue section were collected in 10 min with an effective acquisition rate of roughly 30 pixels/s. These results represent more than a 10-fold increase in throughput compared with current commercially available instrumentation. Experiments aimed at improving conditions for continuous laser raster sampling for imaging are reported, highlighting proper laser repetition rates and stage velocities to avoid signal degradation from significant oversampling. As new high spatial resolution and large sample area applications present themselves, the development of high-speed microprobe MALDI imaging mass spectrometry is essential to meet the needs of those seeking new technologies for rapid molecular imaging. PMID:21953043

  9. Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite

    USGS Publications Warehouse

    Morelli, J.J.; Hercules, D.M.; Lyons, P.C.; Palmer, C.A.; Fletcher, J.D.

    1988-01-01

    The variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS). Variations in Ba, Cr, Ga, Sr, Ti, and V concentrations among the coals were determined using the LAMM A-1000 instrument. LAMMS analysis is not limited to these elements; their selection illustrates the application of the technique. Ba, Cr, Ga, Sr, Ti, and V have minimal site-to-site variance in the vitrinite macerals of the studied coals as measured by LAMMS. The LAMMS data were compared with bulk elemental data obtained by instrumental neutron activation analysis (INAA) and D. C. arc optical emission spectroscopy (DCAS) in order to determine the reliability of the LAMMS data. The complex nature of the ionization phenomena in LAMMS and the lack of standards characterized on a microscale makes obtaining quantitative elemental data within the ionization microvolume difficult; however, we demonstrate that the relative variation of an element among vitrinites from different coal beds in the eastern United States can be observed using LAMMS in a "bulk" mode by accumulating signal intensities over several microareas of each vitrinite. Our studies indicate gross changes (greater than a factor of 2 to 5 depending on the element) can be monitored when the elemental concentration is significantly above the detection limit. "Bulk" mode analysis was conducted to evaluate the accuracy of future elemental LAMMS microanalyses. The primary advantage of LAMMS is the inherent spatial resolution, ~ 20 ??m for coal. Two different vitrite bands in the Lower Bakerstown coal bed (CLB-1) were analyzed. The analysis did not establish any certain concentration differences in Ba, Cr, Ga, Sr, Ti, and V between the two bands. ?? 1988 Springer-Verlag.

  10. Fourier Transform Mass Spectrometry

    PubMed Central

    Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander

    2011-01-01

    This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook. PMID:21742802

  11. Fourier Transform Mass Spectrometry.

    ERIC Educational Resources Information Center

    Gross, Michael L.; Rempel, Don L.

    1984-01-01

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

  12. Mass Spectrometry for the Masses

    ERIC Educational Resources Information Center

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

    2004-01-01

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

  13. Plasma Desorption Mass Spectrometry: Coming of Age.

    ERIC Educational Resources Information Center

    Cotter, Robert J.

    1988-01-01

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

  14. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

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

  15. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

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

  16. Mass spectrometry. [review of techniques

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  17. Ion Trap Mass Spectrometry

    SciTech Connect

    Eiden, Greg C.

    2005-09-01

    This chapter describes research conducted in a few research groups in the 1990s in which RF quadrupole ion trap mass spectrometers were coupled to a powerful atomic ion source, the inductively coupled plasma used in conventional ICP-MS instruments. Major section titles for this chapter are: RF Quadrupole Ion Traps Features of RF Quadrupole Ion Trap Mass Spectrometers Selective Ion Trapping methods Inductively Coupled Plasma Source Ion Trap Mass Spectrometers

  18. Studies of aerosol at a coastal site using two aerosol mass spectrometry instruments and identification of biogenic particle types

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Harrison, R. M.; Furutani, H.; Prather, K. A.; Coe, H.; Allan, J. D.

    2005-10-01

    During August 2004 an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS Model 3800-100) and an Aerodyne Aerosol Mass Spectrometer (AMS) were deployed at Mace Head during the NAMBLEX campaign. Single particle data (size, positive and negative mass spectra) from the ATOFMS were imported into ART 2a, a neural network algorithm, which assigns individual particles to clusters on the basis of their mass spectral similarities. Results are very consistent with previous time consuming manual classifications (Dall'Osto et al., 2004). Three broad classes were found: sea-salt, dust and carbon-containing particles, with a number of sub-classes within each. The Aerodyne (AMS) instrument was also used during NAMBLEX, providing online, real time measurements of the mass of non-refractory components of aerosol particles as function of their size. The ATOFMS detected a type of particle not identified in our earlier analysis, with a strong signal at m/z 24, likely due to magnesium. This type of particle was detected during the same periods as pure unreacted sea salt particles and is thought to be biogenic, originating from the sea surface. AMS data are consistent with this interpretation, showing an additional organic peak in the corresponding size range at times when the Mg-rich particles are detected. The work shows the ATOFMS and AMS to be largely complementary, and to provide a powerful instrumental combination in studies of atmospheric chemistry.

  19. Unknown exposures: gaps in basic characterization addressed with person-portable gas chromatography-mass spectrometry instrumentation.

    PubMed

    Smith, Philip A; Roe, Marc T A; Sadowski, Charles; Lee, Edgar D

    2011-03-01

    A newly developed person-portable gas chromatography-mass spectrometry (GC-MS) system was used to analyze several solvent standards, contact cement, paint thinner, and polychlorinated biphenyl samples. Passive solid phase microextraction sampling and fast chromatography with a resistively heated low thermal mass GC column were used. Results (combined sampling and analysis) were obtained in <2 min for solvent, contact cement, and paint thinner samples, and in <13 min for the polychlorinated biphenyl sample. Mass spectra produced by the small toroidal ion trap detector used were similar to those produced with heavily used transmission quadrupole mass spectrometers for polychlorinated biphenyl compounds, simple alkanes, and cycloalknes, while mass spectra for benzene and the ketone compounds analyzed showed evidence for ion/molecule reactions in the ion trap. For one of the contact cement samples analyzed, no evidence was found to indicate the presence of n-hexane, although the relevant material safety data sheet listed this ingredient. Specific chemical constituents corresponding to a potentially wide range of petroleum distillate compounds were identifiable from GC-MS analyses. The possibility for an improved basic characterization step in the exposure assessment process exists with the availability of fast, person-portable GC-MS, although work is needed to further refine this tool and understand the best ways it may be used. PMID:21318921

  20. Biological Cluster Mass Spectrometry

    PubMed Central

    Winograd, Nicholas; Garrison, Barbara J.

    2010-01-01

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

  1. MASS SPECTROMETRY IN ENVIRONMENTAL SCIENCES

    EPA Science Inventory

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

  2. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    NASA Astrophysics Data System (ADS)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-06-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

  3. Ion Mobility Spectrometry (IMS) and Mass Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.

    2010-04-20

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

  4. Developments in ion mobility spectrometry-mass spectrometry.

    PubMed

    Collins, D C; Lee, M L

    2002-01-01

    Ion mobility spectrometry (IMS) has been used for over 30 years as a sensitive detector of organic compounds. The following is a brief review of IMS and its principles with an emphasis on its usage when coupled to mass spectrometry. Since its inception, IMS has been interfaced with quadrupole, time-of-flight, and Fourier-transform ion cyclotron resonance mass spectrometry. These hybrid instruments have been employed for the analysis of a variety of target analytes, including biomolecules, explosives, chemical warfare degradation products, and illicit drugs. PMID:11939214

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

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

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

  6. "Magic" Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Trimpin, Sarah

    2016-01-01

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

  7. "Magic" Ionization Mass Spectrometry.

    PubMed

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers. PMID:26486514

  8. Quantitative biomedical mass spectrometry

    NASA Astrophysics Data System (ADS)

    de Leenheer, Andrép; Thienpont, Linda M.

    1992-09-01

    The scope of this contribution is an illustration of the capabilities of isotope dilution mass spectrometry (IDMS) for quantification of target substances in the biomedical field. After a brief discussion of the general principles of quantitative MS in biological samples, special attention will be paid to new technological developments or trends in IDMS from selected examples from the literature. The final section will deal with the use of IDMS for accuracy assessment in clinical chemistry. Methodological aspects considered crucial for avoiding sources of error will be discussed.

  9. Bioaffinity Mass Spectrometry Screening.

    PubMed

    Yang, Ben; Feng, Yun Jiang; Vu, Hoan; McCormick, Brendan; Rowley, Jessica; Pedro, Liliana; Crowther, Gregory J; Van Voorhis, Wesley C; Forster, Paul I; Quinn, Ronald J

    2016-02-01

    Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS or ESI-FTMS) was used to screen 192 natural product extracts and a 659-member natural product-based fragment library for bindings to a potential malaria drug target, Plasmodium falciparum Rab11a (PfRab11a, PF13_0119). One natural product extract and 11 fragments showed binding activity. A new natural product, arborside E, was identified from the active extract of Psydrax montigena as a weak binder. Its binding activity and inhibitory activity against PfRab11a were confirmed by ESI-FTMS titration experiments and an orthogonal enzyme assay. PMID:26773071

  10. Single event mass spectrometry

    DOEpatents

    Conzemius, Robert J.

    1990-01-16

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

  11. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    NASA Astrophysics Data System (ADS)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-05-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  12. Design and performance of a combined secondary ion mass spectrometry-scanning probe microscopy instrument for high sensitivity and high-resolution elemental three-dimensional analysis

    SciTech Connect

    Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel

    2012-06-15

    State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 {mu}m in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program 'SARINA,' which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.

  13. Isotope dilution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Heumann, Klaus G.

    1992-09-01

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

  14. Inorganic trace analysis by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Becker, Johanna Sabine; Dietze, Hans-Joachim

    1998-10-01

    high-purity materials and environmental samples) is used in order to improve the detection limits of trace elements. Furthermore, the determination of chemical elements in the trace and ultratrace concentration range is often difficult and can be disturbed through mass interferences of analyte ions by molecular ions at the same nominal mass. By applying double-focusing sector field mass spectrometry at the required mass resolution—by the mass spectrometric separation of molecular ions from the analyte ions—it is often possible to overcome these interference problems. Commercial instrumental equipment, the capability (detection limits, accuracy, precision) and the analytical application fields of mass spectrometric methods for the determination of trace and ultratrace elements and for surface analysis are discussed.

  15. Nanopore Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bush, Joseph; Mihovilovic, Mirna; Maulbetsch, William; Frenchette, Layne; Moon, Wooyoung; Pruitt, Cole; Bazemore-Walker, Carthene; Weber, Peter; Stein, Derek

    2013-03-01

    We report on the design, construction, and characterization of a nanopore-based ion source for mass spectrometry. Our goal is to field-extract ions directly from solution into the high vacuum to enable unit collection efficiency and temporal resolution of sequential ion emissions for DNA sequencing. The ion source features a capillary whose tip, measuring tens to hundreds of nanometers in inner diameter, is situated in the vacuum ~ 1.5 cm away from an extractor electrode. The capillary was filled with conductive solution and voltage-biased relative to the extractor. Applied voltages of hundreds of volts extracted tens to hundreds of nA of current from the tip. A mass analysis of the extracted ions showed primarily singly charged clusters comprising the cation or anion solvated by several solvent molecules. Our interpretation of these results, based on the works of Taylor and of de la Mora, is that the applied electric stresses distort the fluid meniscus into a Taylor cone, where electric fields reach ~ 1V/nm and induce significant ion evaporation. Accordingly, the abundances of extracted ionic clusters resemble a Boltzmann distribution. This work was supported by NIH grant NHGRI 1R21HG005100-01.

  16. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  17. Comparison of water isotope-ratio determinations using two cavity ring-down instruments and classical mass spectrometry in continuous ice-core analysis.

    PubMed

    Maselli, Olivia J; Fritzsche, Diedrich; Layman, Lawrence; McConnell, Joseph R; Meyer, Hanno

    2013-01-01

    We present a detailed comparison between subsequent versions of commercially available wavelength-scanned cavity ring-down water isotope analysers (L2120-i and L2130-i, Picarro Inc.). The analysers are used in parallel in a continuous mode by adaption of a low-volume flash evaporation module. Application of the analysers to ice-core analysis is assessed by comparison between continuous water isotope measurements of a glacial ice-core from Severnaya Zemlya with discrete isotope-ratio mass spectrometry measurements performed on parallel samples from the same ice-core. The great advances between instrument versions, particularly in the measurement of δ(2)H, allow the continuous technique to achieve the same high level of accuracy and precision obtained using traditional isotope spectrometry techniques in a fraction of the experiment time. However, when applied to continuous ice-core measurements, increased integration times result in a compromise of the achievable depth resolution of the ice-core records. PMID:23713832

  18. Ion mobility-mass spectrometry.

    PubMed

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

    2008-01-01

    This review article compares and contrasts various types of ion mobility-mass spectrometers available today and describes their advantages for application to a wide range of analytes. Ion mobility spectrometry (IMS), when coupled with mass spectrometry, offers value-added data not possible from mass spectra alone. Separation of isomers, isobars, and conformers; reduction of chemical noise; and measurement of ion size are possible with the addition of ion mobility cells to mass spectrometers. In addition, structurally similar ions and ions of the same charge state can be separated into families of ions which appear along a unique mass-mobility correlation line. This review describes the four methods of ion mobility separation currently used with mass spectrometry. They are (1) drift-time ion mobility spectrometry (DTIMS), (2) aspiration ion mobility spectrometry (AIMS), (3) differential-mobility spectrometry (DMS) which is also called field-asymmetric waveform ion mobility spectrometry (FAIMS) and (4) traveling-wave ion mobility spectrometry (TWIMS). DTIMS provides the highest IMS resolving power and is the only IMS method which can directly measure collision cross-sections. AIMS is a low resolution mobility separation method but can monitor ions in a continuous manner. DMS and FAIMS offer continuous-ion monitoring capability as well as orthogonal ion mobility separation in which high-separation selectivity can be achieved. TWIMS is a novel method of IMS with a low resolving power but has good sensitivity and is well intergrated into a commercial mass spectrometer. One hundred and sixty references on ion mobility-mass spectrometry (IMMS) are provided. PMID:18200615

  19. Linear electric field mass spectrometry

    DOEpatents

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

    1992-12-01

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

  20. Linear electric field mass spectrometry

    DOEpatents

    McComas, David J.; Nordholt, Jane E.

    1992-01-01

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

  1. Introduction to mass spectrometry-based proteomics.

    PubMed

    Matthiesen, Rune; Bunkenborg, Jakob

    2013-01-01

    Mass spectrometry has been widely applied to study biomolecules and one rapidly developing field is the global analysis of proteins, proteomics. Understanding and handling mass spectrometry data is a multifaceted task that requires many decisions to be made to get the most comprehensive information from an experiment. Later chapters in this book deal in-depth with various aspects of the process and how different tools can be applied to the many analytical challenges. This introductory chapter is intended as a basic introduction to mass spectrometry (MS)-based proteomics to set the scene for newcomers and give pointers to reference material. There are many applications of mass spectrometry in proteomics and each application is associated with some analytical choices, instrumental limitations and data processing steps that depend on the aim of the study and means of conducting it. Different aspects of the proteome can be explored by choosing the right combination of sample preparation, MS instrumentation and data processing. This chapter gives an outline for some of these commonly used setups and some of the key concepts, many of which are explored in greater depth in later chapters. PMID:23666720

  2. Digital Imaging Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bamberger, Casimir; Renz, Uwe; Bamberger, Andreas

    2011-06-01

    Methods to visualize the two-dimensional (2D) distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by matrix-assisted laser desorption/ionization (MALDI) directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84 ± 35) μm with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allows parallel imaging of selected masses. The digital imaging mass spectrometer proves high hit-multiplicity, straightforward image reconstruction, and potential for high-speed readout at 4 kHz or more. This device demonstrates a simple way of true image acquisition like a digital photographic camera. The technology may enable a fast analysis of biomolecular samples in near future.

  3. Space Applications of Mass Spectrometry. Chapter 31

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  4. Symposium on accelerator mass spectrometry

    SciTech Connect

    1981-01-01

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

  5. Accelerator mass spectrometry: Proceedings of the fourth international symposium on accelerator mass spectrometry

    SciTech Connect

    Gove, H.E.; Litherland, A.E.; Elmore, D.

    1987-01-01

    This report is a volume of the journal Nuclear Instruments and Methods in Physics Research B: Beam Interactions with Materials and Atoms. This particular volume is concerned with accelerator mass spectrometry. The sections of this issue are: Advances in AMS techniques; Archaeology and ecology; Glaciology and climatology; Cosmochemistry and in situ production; Ocean and atmospheric sciences; Hydrology and geology; Astrophysics, nuclear physics and lasers.

  6. Nuclear applications of inorganic mass spectrometry.

    PubMed

    De Laeter, John

    2010-01-01

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

  7. Mass spectrometry for biomarker development

    SciTech Connect

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

    2015-06-19

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

  8. Mass spectrometry of large complexes.

    PubMed

    Bich, Claudia; Zenobi, Renato

    2009-10-01

    Mass spectrometry is becoming a more and more powerful tool for investigating protein complexes. Recent developments, based on different ionization techniques, electrospray, desorption/ionization and others are contributing to the usefulness of MS to describe the organization and structure of large non-covalent assemblies. PMID:19782560

  9. Electrospray Ionization Mass Spectrometry

    SciTech Connect

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

    2014-06-13

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

  10. Accelerator mass spectrometry

    SciTech Connect

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

    1995-06-01

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

  11. Ambient Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Huang, Min-Zong; Yuan, Cheng-Hui; Cheng, Sy-Chyi; Cho, Yi-Tzu; Shiea, Jentaie

    2010-07-01

    Mass spectrometric ionization methods that operate under ambient conditions and require minimal or no sample pretreatment have attracted much attention in such fields as biomedicine, food safety, antiterrorism, pharmaceuticals, and environmental pollution. These technologies usually involve separate ionization and sample-introduction events, allowing independent control over each set of conditions. Ionization is typically performed under ambient conditions through use of existing electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) techniques. Rapid analyses of gas, liquid, and solid samples are possible with the adoption of various sample-introduction methods. This review sorts different ambient ionization techniques into two main subcategories, primarily on the basis of the ionization processes, that are further differentiated in terms of the approach used for sampling.

  12. MASS SPECTROMETRY-BASED METABOLOMICS

    PubMed Central

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

    2007-01-01

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

  13. Review on ion mobility spectrometry. Part 1: current instrumentation.

    PubMed

    Cumeras, R; Figueras, E; Davis, C E; Baumbach, J I; Gràcia, I

    2015-03-01

    Ion Mobility Spectrometry (IMS) is a widely used and 'well-known' technique of ion separation in the gaseous phase based on the differences in ion mobilities under an electric field. All IMS instruments operate with an electric field that provides space separation, but some IMS instruments also operate with a drift gas flow that provides also a temporal separation. In this review we will summarize the current IMS instrumentation. IMS techniques have received an increased interest as new instrumentation and have become available to be coupled with mass spectrometry (MS). For each of the eight types of IMS instruments reviewed it is mentioned whether they can be hyphenated with MS and whether they are commercially available. Finally, out of the described devices, the six most-consolidated ones are compared. The current review article is followed by a companion review article which details the IMS hyphenated techniques (mainly gas chromatography and mass spectrometry) and the factors that make the data from an IMS device change as a function of device parameters and sampling conditions. These reviews will provide the reader with an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465076

  14. Review on Ion Mobility Spectrometry. Part 1: Current Instrumentation

    PubMed Central

    Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

    2014-01-01

    Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. All IMS instruments operate with an electric field that provides space separation, but some IMS instruments also operate with a drift gas flow which provides also a temporal separation. In this review we will summarize the current IMS instrumentation. IMS techniques have received an increased interest as new instrumentation has become available to be coupled with mass spectrometry (MS). For each of the eight types of IMS instruments reviewed it is mentioned whether they can be hyphenated with MS and whether they are commercially available. Finally, out of the described devices, the six most-consolidated ones are compared. The current review article is followed by a companion review article which details the IMS hyphenated techniques (mainly gas chromatography and mass spectrometry) and the factors that make the data from an IMS device change as function of device parameters and sampling conditions. These reviews will provide the reader with an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465076

  15. Mass spectrometry and renal calculi

    PubMed Central

    Purcarea, VL; Sisu, I; Sisu, E

    2010-01-01

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

  16. Mass spectrometry of aerospace materials

    NASA Technical Reports Server (NTRS)

    Colony, J. A.

    1976-01-01

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

  17. Application of mass spectrometry for metabolite identification.

    PubMed

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

    2006-06-01

    Metabolism studies play a pivotal role in drug discovery and development. Characterization of metabolic "hot-spots" as well as reactive and pharmacologically active metabolites is critical to designing new drug candidates with improved metabolic stability, toxicological profile and efficacy. Metabolite identification in the preclinical species used for safety evaluation is required in order to determine whether human metabolites have been adequately tested during non-clinical safety assessment. From an instrumental standpoint, high performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) dominates all analytical tools used for metabolite identification. The general strategies employed for metabolite identification in both drug discovery and drug development settings together with sample preparation techniques are reviewed herein. These include a discussion of the various ionization methods, mass analyzers, and tandem mass spectrometry (MS/MS) techniques that are used for structural characterization in a modern drug metabolism laboratory. Mass spectrometry-based techniques, such as stable isotope labeling, on-line H/D exchange, accurate mass measurement to enhance metabolite identification and recent improvements in data acquisition and processing for accelerating metabolite identification are also described. Rounding out this review, we offer additional thoughts about the potential of alternative and less frequently used techniques such as LC-NMR/MS, CRIMS and ICPMS. PMID:16787159

  18. Foreword: Collision and reaction cell techniques in atomic mass spectrometry

    SciTech Connect

    Koppenaal, David W.; Eiden, Greg C.

    2004-01-01

    This contribution is a guest editorial statement and technical assessment for a special issue of the Royal Society of Chemistry journal entitled Journal of Analytical Atomic Spectrometry (JAAS). The editorial introduces the subject area of collision and reaction cells in atomic mass spectrometry, reviews current literature and commercial instrumentation trends, and previews four perspective and numerous research articles contained in the special journal issue.

  19. Biological particle analysis by mass spectrometry

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  20. Advances in imaging secondary ion mass spectrometry for biological samples

    SciTech Connect

    Boxer, Steven G.; Kraft, Mary L.; Weber, Peter K.

    2008-12-16

    Imaging mass spectrometry combines the power of mass spectrometry to identify complex molecules based on mass with sample imaging. Recent advances in secondary ion mass spectrometry have improved sensitivity and spatial resolution, so that these methods have the potential to bridge between high-resolution structures obtained by X-ray crystallography and cyro-electron microscopy and ultrastructure visualized by conventional light microscopy. Following background information on the method and instrumentation, we address the key issue of sample preparation. Because mass spectrometry is performed in high vacuum, it is essential to preserve the lateral organization of the sample while removing bulk water, and this has been a major barrier for applications to biological systems. Furthermore, recent applications of imaging mass spectrometry to cell biology, microbial communities, and biosynthetic pathways are summarized briefly, and studies of biological membrane organization are described in greater depth.

  1. Advances in imaging secondary ion mass spectrometry for biological samples

    DOE PAGESBeta

    Boxer, Steven G.; Kraft, Mary L.; Weber, Peter K.

    2008-12-16

    Imaging mass spectrometry combines the power of mass spectrometry to identify complex molecules based on mass with sample imaging. Recent advances in secondary ion mass spectrometry have improved sensitivity and spatial resolution, so that these methods have the potential to bridge between high-resolution structures obtained by X-ray crystallography and cyro-electron microscopy and ultrastructure visualized by conventional light microscopy. Following background information on the method and instrumentation, we address the key issue of sample preparation. Because mass spectrometry is performed in high vacuum, it is essential to preserve the lateral organization of the sample while removing bulk water, and this hasmore » been a major barrier for applications to biological systems. Furthermore, recent applications of imaging mass spectrometry to cell biology, microbial communities, and biosynthetic pathways are summarized briefly, and studies of biological membrane organization are described in greater depth.« less

  2. Imaging Mass Spectrometry in Neuroscience

    PubMed Central

    2013-01-01

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

  3. A Radio Frequency Quadrupole Instrument for use with Accelerator Mass Spectrometry: Application to Low Kinetic Energy Reactive Isobar Suppression and Gas--Phase Anion Reaction Studies

    NASA Astrophysics Data System (ADS)

    Eliades, John Alexander

    A radio frequency (rf) quadrupole instrument, currently known as an Isobar Separator for Anions (ISA), has been integrated into an Accelerator Mass Spectrometry (AMS) system to facilitate anion--gas reactions before the tandem accelerator. An AMS Cs+ sputter source provided ≥ 15 keV ions that were decelerated in the prototype ISA to < 20 eV for reaction in a single collision cell and re-accelerated for AMS analysis. Reaction based isobar suppression capabilities were assessed for smaller AMS systems and a new technique for gas--phase reaction studies was developed. Isobar suppression of 36S-- and 12C3-- for 36Cl analysis, and YF3-- and ZrF3-- for 90Sr analysis were studied in NO2 with deceleration to ≤ 12 eV. Observed attenuation cross sections, sigma [x 10--15 cm2], were sigma(S-- + NO2) = 6.6, sigma(C3-- + NO2) = 4.2, sigma(YF3-- + NO 2) = 7.6, sigma(ZrF3-- + NO2) = 19. With 8 mTorr NO2, relative attenuations of S-- /Cl-- ˜ 10--6, C 3--/Cl-- ˜ 10--7 , YF3--/SrF3-- ˜ 5 x 10--5 and ZrF3-- /SrF3-- ˜ 4 x 10--6 were observed with Cl-- ˜ 30% and SrF 3-- > 90% transmission. Current isobar attenuation limits with ≤ 1.75 MV accelerator terminal voltage and ppm impurity levels were calculated to be 36S--/Cl-- ˜ 4 x 10--16, 12C3 --/Cl-- ˜ 1.2 x 10--16, 90YF3--/SrF3-- ˜ 10--15 and 90ZrF3 --/SrF3-- ˜ 10--16 . Using 1.75 MV, four 36Cl reference standards in the range 4 x 10--13 ≤ 36Cl/Cl ≤ 4 x 10 --11 were analyzed with 8 mTorr NO2. The measured 36Cl/Cl ratios plotted very well against the accepted values. A sample impurity content S/Cl ≤ 6 x 10--5 was measured and a background level of 36S--/Cl ≤ 9 x 10--15 was determined. Useful currents of a wide variety of anions are produced in AMS sputter sources and molecules can be identified relatively unambiguously by stripping fragments from tandem accelerators. Reactions involving YF3 --, ZrF3--, S-- and SO-- + NO2 in the ISA analyzed by AMS are described, and some interesting reactants are identified.

  4. Glycosaminoglycan Glycomics Using Mass Spectrometry*

    PubMed Central

    Zaia, Joseph

    2013-01-01

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

  5. A mass spectrometry primer for mass spectrometry imaging

    PubMed Central

    Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2011-01-01

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

  6. Identification of Unknown Contaminants in Water Samples from ISS Employing Liquid Chromatography/Mass Spectrometry/Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Rutz, Jeffrey A.; Schultz, John R.

    2008-01-01

    Mass Spectrometry/Mass Spectrometry (MS/MS) is a powerful technique for identifying unknown organic compounds. For non-volatile or thermally unstable unknowns dissolved in liquids, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) is often the variety of MS/MS used for the identification. One type of LC/MS/MS that is rapidly becoming popular is time-of-flight (TOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of one unknown is reviewed in detail in this paper. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns.

  7. Electrophoresis-mass spectrometry probe

    DOEpatents

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

    1987-11-10

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

  8. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

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

  9. Secondary Ion Mass Spectrometry of Environmental Aerosols

    SciTech Connect

    Gaspar, Daniel J.; Cliff, John B.

    2010-08-01

    Atmospheric particles influence many aspects of climate, air quality and human health. Understanding the composition, chemistry and behavior of atmospheric aerosols is a key remaining challenge in improving climate models. Furthermore, particles may be traced back to a particular source based on composition, stable isotope ratios, or the presence of particular surface chemistries. Finally, the characterization of atmospheric particles in the workplace plays an important role in understanding the potential for exposure and environmental and human health effects to engineered and natural nanoscale particles. Secondary ion mass spectrometry (SIMS) is a useful tool in determining any of several aspects of the structure, composition and chemistry of these particles. Often used in conjunction with other surface analysis and electron microscopy methods, SIMS has been used to determine or confirm reactions on and in particles, the presence of particular organic species on the surface of atmospheric aerosols and several other interesting and relevant findings. Various versions of SIMS instruments – dynamic SIMS, time of flight secondary ion mass spectrometry or TOF-SIMS, nanoSIMS – have been used to determine specific aspects of aerosol structure and chemistry. This article describes the strengths of each type of SIMS instrument in the characterization of aerosols, along with guidance on sample preparation, specific characterization specific to the particular information sought in the analysis. Examples and guidance are given for each type of SIMS analysis.

  10. Neuroscience and Accelerator Mass Spectrometry

    SciTech Connect

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

    2004-08-02

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

  11. The life sciences mass spectrometry research unit.

    PubMed

    Hopfgartner, Gérard; Varesio, Emmanuel

    2012-01-01

    The Life Sciences Mass Spectrometry (LSMS) research unit focuses on the development of novel analytical workflows based on innovative mass spectrometric and software tools for the analysis of low molecular weight compounds, peptides and proteins in complex biological matrices. The present article summarizes some of the recent work of the unit: i) the application of matrix-assisted laser desorption/ionization (MALDI) for mass spectrometry imaging (MSI) of drug of abuse in hair, ii) the use of high resolution mass spectrometry for simultaneous qualitative/quantitative analysis in drug metabolism and metabolomics, and iii) the absolute quantitation of proteins by mass spectrometry using the selected reaction monitoring mode. PMID:22867547

  12. MASS SPECTROMETRY OF FATTY ALDEHYDES

    PubMed Central

    Berdyshev, Evgeny V.

    2011-01-01

    Fatty aldehydes are important components of the cellular lipidome. Significant interest has been developed towards the analysis of the short chain α,β-unsaturated and hydroxylated aldehydes formed as a result of oxidation of polyunsaturated fatty acids. Multiple gas chromatography-mass spectrometry (GC/MS) and subsequently liquid chromatography-mass spectrometry (LC/MS) approaches have been developed to identify and quantify short-chain as well as long-chain fatty aldehydes. Due to the ability to non-enzymaticaly form Schiff bases with amino groups of proteins, lipids, and with DNA guanidine, free aldehydes are viewed as a marker or metric of fatty acid oxidation and not the part of intracellular signaling pathways which has significantly limited the overall attention this group of molecules have received. This review provides an overview of current GC/MS and LC/MS approaches of fatty aldehyde analysis as well as discusses technical challenges standing in the way of free fatty aldehyde quantitation. PMID:21930240

  13. Mass Spectrometry for Rapid Characterization of Microorganisms

    NASA Astrophysics Data System (ADS)

    Demirev, Plamen A.; Fenselau, Catherine

    2008-07-01

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

  14. Protein Sequencing with Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ziady, Assem G.; Kinter, Michael

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

  15. Structural determination of glycosphingolipids as lithiated adducts by electrospray ionization mass spectrometry using low-energy collisional-activated dissociation on a triple stage quadrupole instrument.

    PubMed

    Hsu, F F; Turk, J

    2001-01-01

    Structural characterization of glycosphingolipids as their lithiated adducts using low-energy collisional-activated dissociation (CAD) tandem mass spectrometry with electrospray ionization (ESI) is described. The tandem mass spectra contain abundant fragment ions reflecting the long chain base (LCB), fatty acid, and the sugar constituent of the molecule and permit unequivocal identification of cerebrosides, di-, trihexosyl ceramides and globosides. The major fragmentation pathways arise from loss of the sugar moiety to yield a lithiated ceramide ion, which undergoes further fragmentation to form multiple fragment ions that confirm the structures of the fatty acid and LCB. The mechanisms for the ion formation and the possible configuration of the fragment ions, resulting from CAD of the lithiated molecular ions ([M + Li]+) of monoglycosylceramides are proposed. The mechanisms were supported by CAD and source CAD tandem mass spectra of various cerebrosides and of their analogous molecules prepared by H-D exchange. Constant neutral loss and precursor ion scannings to identify galactosylceramides with sphingosine or sphinganine LCB subclasses, and with specific N-2-hydroxyl fatty acid subclass in mixtures are also demonstrated. PMID:11142362

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

    ERIC Educational Resources Information Center

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

    1982-01-01

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

  17. Nanotip Ambient Ionization Mass Spectrometry.

    PubMed

    Zhou, Zhenpeng; Lee, Jae Kyoo; Kim, Samuel C; Zare, Richard N

    2016-05-17

    A method called nanotip ambient ionization mass spectrometry (NAIMS) is described, which applies high voltage between a tungsten nanotip and a metal plate to generate a plasma in which ionized analytes on the surface of the metal plate are directed to the inlet and analyzed by a mass spectrometer. The dependence of signal intensity is investigated as a function of the tip-to-plate distance, the tip size, the voltage applied at the tip, and the current. These parameters are separately optimized to achieve sensitivity or high spatial resolution. A partially observable Markov decision process is used to achieve a stabilized plasma as well as high ionization efficiency. As a proof of concept, the NAIMS technique has been applied to phenanthrene and caffeine samples for which the limits of detection were determined to be 0.14 fmol for phenanthrene and 4 amol for caffeine and to a printed caffeine pattern for which a spatial resolution of 8 ± 2 μm, and the best resolution of 5 μm, was demonstrated. The limitations of NAIMS are also discussed. PMID:27087600

  18. Mass Spectrometry on Future Mars Landers

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  19. Perspectives and retrospectives in mass spectrometry: one view.

    PubMed

    Cooks, R Graham; Ifa, Demian R; Sharma, Gautam; Tadjimukhamedov, Fatkhulla Kh; Ouyang, Zheng

    2010-01-01

    Mass spectrometry benefits from a flexible definition which equates it with many aspects of the science of matter in the ionized state. The field continues to expand rapidly, not only to encompass larger and more complex molecules through more powerful instruments, but simultaneously towards in-situ measurements made using smaller, more flexible and just-sufficiently-powerful instruments. The senior author has been fortunate to work in mass spectrometry from 1967 to the present and has been involved in a wide range of efforts which have covered analytical, biological, organic, instrumental and physical aspects of the subject. This effort has been made in the company of a remarkable set of colleagues. From this vantage, it is possible to look both backwards and forwards in this prospective and retrospective piece. This presentation involves a personal look at places, people, instruments, and concepts engaged in along a path through Mass Spectrometry. The journey goes from Natal, South Africa, via Cambridge, UK, through Kansas and on to Purdue University, in the great state of Indiana. It starts with natural products chemistry and moves to the physical chemistry of fragmentation and energy partitioning on to complex mixture analysis by tandem mass spectrometry and hence to the concepts of thermochemical determination by the kinetic method, preparation of materials by ion soft landing, the possible role of amino acid clusters in the origin of homochiral life, and the elaboration of a set of ambient ionization methods for chemical analysis performed using samples in their native state. Special attention is given to novel concepts and instrumentation and to the emerging areas of ambient ionization, molecular imaging and miniature mass spectrometers. Personal mass spectrometers appear to be just over the horizon as is the large-scale use of mass spectrometry in field-based analysis, including point-of-care medical diagnostics. PMID:20530836

  20. Measurement of pernitric acid (HO2NO2) using chemical ionization mass spectrometry (CIMS) with I-·H2O as the reagent ions: instrumentation and observations

    NASA Astrophysics Data System (ADS)

    Chen, D.; Huey, L. G.; Tanner, D.; Ng, N. L.; Li, J.; Dibb, J. E.; Wang, Y.

    2015-12-01

    Peroxynitric acid (HO2NO2) is formed by the association reaction of HO2 and NO2, which couples both the HOx (HO2+OH) and NOx (=NO2+NO) families. The thermal decomposition at higher temperatures is sufficiently fast that HO2NO2 is in steady state with HO2 and NO2. This allows HO2 levels to be inferred from HO2NO2 observations. In Polar Regions and higher altitudes, significant levels of HO2NO2 can build up and influences local HOx and NOx photochemistry. Here, we present an in situ measurement technique of HO2NO2 based on chemical ionization mass spectrometry (CIMS) using the reagent ion I- and its hydrated form I-·H2O, together with our calibration technique for HO2NO2 measurements. We will also present observations of HO2NO2: (1) in a polar boundary layer on top of the Greenland Ice Sheet during summer 2011, and (2) in an urban boundary layer in metropolitan Atlanta during winter 2014. The local chemistry of HO2NO2 at Summit will be evaluated. The local HO2 in Atlanta will be inferred and assessed with models.

  1. Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Hutchinson, Robert W.; McLachlin, Katherine M.; Riquelme, Paloma; Haarer, Jan; Broichhausen, Christiane; Ritter, Uwe; Geissler, Edward K.; Hutchinson, James A.

    2015-01-01

    ABSTRACT New analytical techniques for multiparametric characterisation of individual cells are likely to reveal important information about the heterogeneity of immunological responses at the single-cell level. In this proof-of-principle study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to the problem of concurrently detecting 24 lineage and activation markers expressed by human leucocytes. This approach was sufficiently sensitive and specific to identify subpopulations of isolated T, B, and natural killer cells. Leucocyte subsets were also accurately detected within unfractionated peripheral blood mononuclear cells preparations. Accordingly, we judge LA-ICP-MS to be a suitable method for assessing expression of multiple tissue antigens in solid-phase biological specimens, such as tissue sections, cytospins, or cells grown on slides. These results augur well for future development of LA-ICP-MS–based bioimaging instruments for general users. PMID:27500232

  2. NCBI Peptidome: a new repository for mass spectrometry proteomics data

    PubMed Central

    Ji, Li; Barrett, Tanya; Ayanbule, Oluwabukunmi; Troup, Dennis B.; Rudnev, Dmitry; Muertter, Rolf N.; Tomashevsky, Maxim; Soboleva, Alexandra; Slotta, Douglas J.

    2010-01-01

    Peptidome is a public repository that archives and freely distributes tandem mass spectrometry peptide and protein identification data generated by the scientific community. Data from all stages of a mass spectrometry experiment are captured, including original mass spectra files, experimental metadata and conclusion-level results. The submission process is facilitated through acceptance of data in commonly used open formats, and all submissions undergo syntactic validation and curation in an effort to uphold data integrity and quality. Peptidome is not restricted to specific organisms, instruments or experiment types; data from any tandem mass spectrometry experiment from any species are accepted. In addition to data storage, web-based interfaces are available to help users query, browse and explore individual peptides, proteins or entire Samples and Studies. Results are integrated and linked with other NCBI resources to ensure dissemination of the information beyond the mass spectroscopy proteomics community. Peptidome is freely accessible at http://www.ncbi.nlm.nih.gov/peptidome. PMID:19942688

  3. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    ERIC Educational Resources Information Center

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  4. Atomic spectrometry update - atomic mass spectrometry.

    SciTech Connect

    Bacon, J.; Crain, J. S.; McMahon, A. W.; Williams, J. G.; Analytical Chemistry Laboratory; The Macaulay Land Use Research Inst.; Manchester Metropolitan Univ.; Imperial Coll.

    1996-10-01

    The MS and XRF updates have been published together since their introduction in 1988. In the last few years, however, the two sections have been prepared independently of each other and it therefore seemed appropriate to publish the two sections separately. With effect from this issue, the MS Update will appear in the October issue of JAAS and the XRF Update in the November issue. The format used for the MS section is broadly similar to that used last year, with some additional sub-headings. This Update is intended to cover all atomic and stable isotopic MS techniques, but not those used in studies of fundamental nuclear physics and exotic nuclei far from stability. Also excluded are those reports in which MS is used as a tool in the study of molecular processes and of gaseous components. the review is based on critical selection of developments in instrumentation and methodology, notable for their innovation, originality or achievement of significant advances, and is not intended to be comprehensive in its coverage. Conference papers are only included if they contain enough information to show they meet these criteria, and our policy in general remains one of waiting for a development to appear in a full paper before inclusion in the review. a similar policy applies to foreign language papers unlikely to reach a wide audience. Routine applications of atomic MS are not included in this Update and the reader is referred to the Updates on Industrial Analysis: Metals, Chemicals and Advanced Materials (96/416), Environmental Analysis (96/1444) and Clinical and Biological Materials, Food and Beverages (96/2479). Also excluded are those applications, even if not routine, which use atomic spectroscopy as a tool for the study of a non-atomic property, for example, the use of stable isotope labeling of carbon or nitrogen in biomolecules in metabolic studies. There have been few general reviews on atomic MS of note in the period covered by this update. That of Colodner et al

  5. Characterization of microbial siderophores by mass spectrometry.

    PubMed

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

    2016-01-01

    Siderophores play important roles in microbial iron piracy, and are applied as infectious disease biomarkers and novel pharmaceutical drugs. Inductively coupled plasma and molecular mass spectrometry (ICP-MS) combined with high resolution separations allow characterization of siderophores in complex samples taking advantages of mass defect data filtering, tandem mass spectrometry, and iron-containing compound quantitation. The enrichment approaches used in siderophore analysis and current ICP-MS technologies are reviewed. The recent tools for fast dereplication of secondary metabolites and their databases are reported. This review on siderophores is concluded with their recent medical, biochemical, geochemical, and agricultural applications in mass spectrometry context. PMID:25980644

  6. Broadband Analysis of Bioagents by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Fenselau, Catherine; Wynne, Colin; Edwards, Nathan

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

  7. imzML: Imaging Mass Spectrometry Markup Language: A common data format for mass spectrometry imaging.

    PubMed

    Römpp, Andreas; Schramm, Thorsten; Hester, Alfons; Klinkert, Ivo; Both, Jean-Pierre; Heeren, Ron M A; Stöckli, Markus; Spengler, Bernhard

    2011-01-01

    Imaging mass spectrometry is the method of scanning a sample of interest and generating an "image" of the intensity distribution of a specific analyte. The data sets consist of a large number of mass spectra which are usually acquired with identical settings. Existing data formats are not sufficient to describe an MS imaging experiment completely. The data format imzML was developed to allow the flexible and efficient exchange of MS imaging data between different instruments and data analysis software.For this purpose, the MS imaging data is divided in two separate files. The mass spectral data is stored in a binary file to ensure efficient storage. All metadata (e.g., instrumental parameters, sample details) are stored in an XML file which is based on the standard data format mzML developed by HUPO-PSI. The original mzML controlled vocabulary was extended to include specific parameters of imaging mass spectrometry (such as x/y position and spatial resolution). The two files (XML and binary) are connected by offset values in the XML file and are unambiguously linked by a universally unique identifier. The resulting datasets are comparable in size to the raw data and the separate metadata file allows flexible handling of large datasets.Several imaging MS software tools already support imzML. This allows choosing from a (growing) number of processing tools. One is no longer limited to proprietary software, but is able to use the processing software which is best suited for a specific question or application. On the other hand, measurements from different instruments can be compared within one software application using identical settings for data processing. All necessary information for evaluating and implementing imzML can be found at http://www.imzML.org . PMID:21063949

  8. Analytical techniques in biomedical stable isotope applications: (isotope ratio) mass spectrometry or infrared spectrometry?

    PubMed

    Stellaard, Frans; Elzinga, Henk

    2005-12-01

    An overview is presented of biomedical applications of stable isotopes in general, but mainly focused on the activities of the Center for Liver, Digestive and Metabolic Diseases of the University Medical Center Groningen. The aims of metabolic studies in the areas of glucose, fat, cholesterol and protein metabolism are briefly explained, as well as the principle of breath testing and the techniques to study body composition and energy expenditure. Much attention is paid to the analytical considerations based upon metabolite concentrations, sample size restrictions, the availability of stable isotope labelled substrates and dose requirements in relation to compound-specific isotope analysis. The instrumental advantages and limitations of the generally used techniques gas chromatography/reaction/isotope ratio mass spectrometry and gas chromatography/mass spectrometry are described as well as the novelties of the recently commercialised liquid chromatography/combustion/isotope ratio mass spectrometry. The present use and future perspective of infrared (IR) spectrometry for clinical and biomedical stable isotope applications are reviewed. In this respect, the analytical demands on IR spectrometry are discussed to enable replacement of isotope ratio mass spectrometry by IR spectrometry, in particular, for the purpose of compound-specific isotope ratio analysis in biological matrices. PMID:16543190

  9. Mass spectrometry imaging and profiling of single cells

    PubMed Central

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

    2012-01-01

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

  10. Methods for recalibration of mass spectrometry data

    DOEpatents

    Tolmachev, Aleksey V.; Smith, Richard D.

    2009-03-03

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

  11. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    SciTech Connect

    Perdian, David C.

    2009-01-01

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  12. Signatures for Mass Spectrometry Data Quality

    PubMed Central

    2014-01-01

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

  13. Environmental applications for the analysis of chlorinated dibenzo-p-dioxins and dibenzofurans using mass spectrometry/mass spectrometry

    SciTech Connect

    Reiner, E.J.; Schellenberg, D.H.; Taguchi, V.Y. )

    1991-01-01

    A mass spectrometry/mass spectrometry-multiple reaction monitoring (MS/MS-MRM) technique for the analysis of all tetra- through octachlorinated dibenzo-p-dioxins (Cl{sub x}DD, x = 4-8) and dibenzofurans (Cl{sub x}DF, x = 4-8) has been developed at the Ministry of the Environment (MOE) utilizing a triple quadrupole mass spectrometer. Optimization of instrumental parameters using the analyte of interest in a direct insertion probe (DIP) resulted in sensitivities approaching those obtainable by high-resolution mass spectrometric (HRMS) methods. All congeners of dioxins and furans were detected in the femtogram range. Results on selected samples indicated that for some matrices, fewer chemical interferences were observed by MS/MS than by HRMS. The technique used to optimize the instrument for chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) analysis is adaptable to other analytes.

  14. Laser ablation inductively coupled plasma mass spectrometry

    SciTech Connect

    Durrant, S.F.

    1996-07-01

    Laser ablation for solid sample introduction to inductively coupled plasma mass spectrometry for bulk and spatially-resolved elemental analysis is briefly reviewed. {copyright} {ital 1996 American Institute of Physics.}

  15. Mass Spectrometry in the Home and Garden

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  16. Ion microprobe mass spectrometry using sputtering atomization and resonance ionization

    SciTech Connect

    Donohue, D.L.; Christie, W.H.; Goeringer, D.E.

    1985-01-01

    Resonance ionization mass spectrometry (RIMS) has recently been developed into a useful technique for isotope ratio measurements. Studies performed in our laboratory (1-6) have been reported for a variety of elements using thermal vaporization sources to produce the atom reservoir for laser-induced resonance ionization. A commercial ion microprobe mass analyzer (IMMA) has been interfaced with a tunable pulsed dye laser for carrying out resonance ionization mass spectrometry of sputtered atoms. The IMMA instrument has many advantages for this work, including a micro-focused primary ion beam (2 ..mu..m in diameter) of selected mass, complete sample manipulation and viewing capability, and a double-focusing mass spectrometer for separation and detection of the secondary or laser-generated ions. Data were obtained demonstrating the number and type of ions formed along with optical spectral information showing the wavelengths at which resonance ionization occurs. 7 refs.

  17. Mass spectrometry on the nanoscale with ion sputtering based techniques: What is feasible

    NASA Astrophysics Data System (ADS)

    Veryovkin, Igor V.; Calaway, Wallis F.; Tripa, C. Emil; Pellin, Michael J.

    2007-08-01

    The potential of ion sputtering based mass spectrometry applied to materials characterization on the nanometer scale is discussed. Analytical approaches and required instrumental capabilities are outlined, and the current state-of-the-art is summarized. A new generation of analytical instruments specifically optimized for laser post-ionization secondary neutral mass spectrometry has been developed at Argonne National Laboratory (ANL). Experimentally verified (or anticipated after near-future upgrades) analytical capabilities of these instruments, capable of quantitative analysis at the nanometer-scale, are reported and compared to secondary ion mass spectrometry.

  18. Microorganism characterization by single particle mass spectrometry.

    PubMed

    Russell, Scott C

    2009-01-01

    In recent years a major effort by several groups has been undertaken to identify bacteria by mass spectrometry at the single cell level. The intent of this review is to highlight the recent progress made in the application of single particle mass spectrometry to the analysis of microorganisms. A large portion of the review highlights improvements in the ionization and mass analysis of bio-aerosols, or particles that contain biologically relevant molecules such as peptides or proteins. While these are not direct applications to bacteria, the results have been central to a progression toward single cell mass spectrometry. Developments in single particle matrix-assisted laser desorption/ionization (MALDI) are summarized. Recent applications of aerosol laser desorption/ionization (LDI) to the analysis of single microorganisms are highlighted. Successful applications of off-line and on-the-fly aerosol MALDI to microorganism detection are discussed. Limitations to current approaches and necessary future achievements are also addressed. PMID:18949817

  19. Mass Spectrometry of Intact Membrane Protein Complexes

    PubMed Central

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

    2014-01-01

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

  20. Analytical aspects of hydrogen exchange mass spectrometry

    PubMed Central

    Engen, John R.; Wales, Thomas E.

    2016-01-01

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

  1. Applications of Hadamard transform to gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

    PubMed

    Lin, Cheng-Huang; Kaneta, Takashi; Chen, Hung-Ming; Chen, Wen-Xiong; Chang, Hung-Wei; Liu, Ju-Tsung

    2008-08-01

    Successful application of the Hadamard transform (HT) technique to gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) is described. Novel sample injection devices were developed to achieve multiple sample injections in both GC and LC instruments. Air pressure was controlled by an electromagnetic valve in GC, while a syringe pump and Tee connector were employed for the injection device in LC. Two well-known, abused drugs, 3,4-methylenedioxy-N-methylamphetamine (MDMA) and N, N-dimethyltryptamine (DMT), were employed as model samples. Both of the injection devices permitted precise successive injections, resulting in clearly modulated chromatograms encoded by Hadamard matrices. After inverse Hadamard transformation of the encoded chromatogram, the signal-to-noise (S/N) ratios of the signals were substantially improved compared with those expected from theoretical values. The S/N ratios were enhanced approximately 10-fold in HT-GC/MS and 6.8 in HT-LC/MS, using the matrices of 1023 and 511, respectively. The HT-GC/MS was successfully applied to the determination of MDMA in the urine sample of a suspect. PMID:18570388

  2. STRUCTURAL CHARACTERIZATION OF SULFONATED AZO DYES USING LIQUID SECONDARY ION MASS SPECTROMETRY/TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    Eight monosulfonated and disulfonated azo dyes were analyzed using liquid secondary ion mass spectrometry/tandem mass spectrometry, in the negative ion mode, under low-energy conditions (110-150 eV). any structurally characteristic fragment ions were obtained, several of which ha...

  3. Mass spectrometry and the environmental sciences

    NASA Astrophysics Data System (ADS)

    Hites, Ronald A.

    1992-09-01

    Research in environmental mass spectrometry focuses on two broad areas: development of new methods for a wide range of pollutants; and using existing methods to understand the fate of pollutants in nature. This paper will present examples of both types of research. In some environmental settings it is important to have rapid analytical turnaround, which suggests that samples should be analyzed in the field rather than in a remote laboratory. Thus, there has been considerable interest in "fieldable" mass spectrometers. Volatile and water soluble analytes can be introduced into a mass spectrometer by passing the water sample over a semi-permeable membrane. The analytes of interest pass through the membrane, but the water does not. This method may be useful in situations that require a continuous readout of concentration. Like mass spectrometrists everywhere, environmental scientists have explored the many facets of liquid chromatographic mass spectrometry. Work in our laboratory has centered on continuous flow fast atom bombardment (CF-FAB) as the LCMS interface. In addition, flow injection analysis is possible using CF-FAB. By avoiding chromatographic separation, the throughput of the analytical system is increased. Frequently, tandem mass spectrometry is necessary to unscramble the chemical signals produced by this technique. Electron capture negative ionization mass spectrometry can achieve sensitivities of a few attomoles for selected compounds; furthermore, the technique can be remarkably specific. These features make it ideal for the analysis of highly chlorinated environmental contaminants such as chlorinated dioxins. Such an application will be presented in detail.

  4. Secondary Ion Mass Spectrometry SIMS XI

    NASA Astrophysics Data System (ADS)

    Gillen, G.; Lareau, R.; Bennett, J.; Stevie, F.

    2003-05-01

    This volume contains 252 contributions presented as plenary, invited and contributed poster and oral presentations at the 11th International Conference on Secondary Ion Mass Spectrometry (SIMS XI) held at the Hilton Hotel, Walt Disney World Village, Orlando, Florida, 7 12 September, 1997. The book covers a diverse range of research, reflecting the rapid growth in advanced semiconductor characterization, ultra shallow depth profiling, TOF-SIMS and the new areas in which SIMS techniques are being used, for example in biological sciences and organic surface characterization. Papers are presented under the following categories: Isotopic SIMS Biological SIMS Semiconductor Characterization Techniques and Applications Ultra Shallow Depth Profiling Depth Profiling Fundamental/Modelling and Diffusion Sputter-Induced Topography Fundamentals of Molecular Desorption Organic Materials Practical TOF-SIMS Polyatomic Primary Ions Materials/Surface Analysis Postionization Instrumentation Geological SIMS Imaging Fundamentals of Sputtering Ion Formation and Cluster Formation Quantitative Analysis Environmental/Particle Characterization Related Techniques These proceedings provide an invaluable source of reference for both newcomers to the field and experienced SIMS users.

  5. Detection of Gunshot Residues Using Mass Spectrometry

    PubMed Central

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

    2014-01-01

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

  6. Dual Polarity Accurate Mass Calibration for ESI and MALDI Mass Spectrometry Using Maltooligosaccharides

    PubMed Central

    Clowers, Brian H.; Dodds, Eric D.; Seipert, Richard R.; Lebrilla, Carlito B.

    2009-01-01

    In view of the fact that memory effects associated with instrument calibration hinder the use of many m/z and tuning standards, identification of robust, comprehensive, inexpensive, and memory-free calibration standards are of particular interest to the mass spectrometry community. Glucose and its isomers are known to have a residue mass of 162.05282 Da; therefore, both linear and branched forms of poly-hexose oligosaccharides possess well defined masses making them ideal candidates for mass calibration. Using a wide range of maltooligosaccharides (MOS) derived from commercially available beers, ions with m/z ratios from ~500 Da to 2500 Da or more have been observed using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and time of flight mass spectrometry (TOF-MS). The mixtures of MOS were further characterized using infrared multiphoton dissociation (IRMPD) and nano-liquid chromatography/mass spectrometry (nano-LC/MS). In addition to providing well defined series of positive and negative calibrant ions using either ESI or MALDI, the MOS are not encumbered by memory effects and are thus well suited mass calibration and instrument tuning standards for carbohydrate analysis. PMID:18655765

  7. Mass spectrometry in natural product chemistry.

    PubMed

    Clayton, E; Hill, H C; Reed, R I

    1966-01-01

    Some mass spectrometric techniques are described which seem applicable to investigating problems in natural product chemistry. One example is of a sample of 5 mcg of a compound being identified by comparison with an authentic sample of prostaglandin derivative. Compared were mass, ion content, and structure. In the prostaglandin/unknown substance comparison, high-resolution mass spectrometry resolved a quandary: apparent additional ions present in the unknown substance were shown to be an impurity. PMID:12262324

  8. Capillary electrophoresis electrospray ionization mass spectrometry interface

    SciTech Connect

    Smith, R.D.; Severs, J.C.

    1999-11-30

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

  9. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

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

  10. Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry.

    PubMed

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2015-03-01

    An ultra-high performance liquid chromatography based method, coupled to high resolution mass spectrometry (UHPLC-HRMS), was developed to permit the detection and quantification of various nitrofuran and chloramphenicol residues in a number of animal based food products. This method is based on the hydrolysis of covalently bound metabolites and derivatization with 2-nitrobenzaldehyde. Clean-up is achieved by a liquid/liquid and a reversed phase/solid phase extraction. Not only are the four conventional nitrofurans (nitrofurantoin, furazolidone, nitrofurazone and furaltadone) detected, but also nifursol, nitrovin and nifuroxazide. Furthermore, an underivatizable nitrofuran (nifurpirinol) and another banned drug (chloramphenicol) can be quantified as well. The compounds are detected in the form of their precursor ions, [M+H](+) and [M-H](-), respectively. The mass resolving power of 70,000 FWHM, and the applied mass window ensure sufficient selectivity and sensitivity. Confirmation is obtained by monitoring the HRMS resolved product ions which were derived from the unit-mass resolved precursor ions. The multiplexing capability of the utilized Orbitrap instrument provides not only highly selective, but also sensitive confirmatory signals. This method has been validated according to the CD 2002/657/EC for the following matrices: muscle, liver, kidney, fish, honey, eggs and milk. PMID:25682427

  11. A Developmental History of Polymer Mass Spectrometry

    ERIC Educational Resources Information Center

    Vergne, Matthew J.; Hercules, David M.; Lattimer, Robert P.

    2007-01-01

    The history of the development of mass spectroscopic methods used to characterize polymers is discussed. The continued improvements in methods and instrumentation will offer new and better ways for the mass spectral characterization of polymers and mass spectroscopy (MS) should be recognized as a complementary polymer characterization method along…

  12. Ultraviolet femtosecond laser ionization mass spectrometry.

    PubMed

    Imasaka, Totaro

    2008-01-01

    For this study, multiphoton ionization/mass spectrometry using an ultraviolet (UV) femtosecond laser was employed for the trace analysis of organic compounds. Some of the molecules, such as dioxins, contain several chlorine atoms and have short excited-state lifetimes due to a "heavy atom" effect. A UV femtosecond laser is, then, useful for efficient resonance excitation and subsequent ionization. A technique of multiphoton ionization using an extremely short laser pulse (e.g., <10 fs), referred to as "impulsive ionization," may have a potential for use in fragmentation-free ionization, thus providing information on molecular weight in mass spectrometry. PMID:18302290

  13. Analysis of Electroblotted Proteins by Mass Spectrometry

    PubMed Central

    Luque-Garcia, Jose L.; Neubert, Thomas A.

    2015-01-01

    Summary Identification of proteins by mass spectrometry is crucial for better understanding of many biological, biochemical, and biomedical processes. Here we describe two methods for the identification of electroblotted proteins by on-membrane digestion prior to analysis by mass spectrometry. These on-membrane methods take approximately half the time of in-gel digestion and provide better digestion efficiency, due to the better accessibility of the protease to the proteins adsorbed onto the nitrocellulose, and better protein sequence coverage, especially for membrane proteins where large and hydrophobic peptides are commonly present. PMID:26139272

  14. Mass spectrometry for pectin structure analysis.

    PubMed

    Ralet, Marie-Christine; Lerouge, Patrice; Quéméner, Bernard

    2009-09-28

    Pectin are extremely complex biopolymers made up of different structural domains. Enzymatic degradation followed by purification and structural analysis of the degradation products proved to be efficient tools for the understanding of pectin fine structure, including covalent interactions between pectic structural domains or with other cell wall polysaccharides. Due to its high sensitivity, high throughput and capacity to analyze mixtures, mass spectrometry has gained more and more importance as a tool for oligosaccharides structural characterization in the past 10 years. This review will focus on the combined use of mass spectrometry and enzymatic digestion for pectins structural characterization. PMID:19058795

  15. Development of Gas Chromatographic Mass Spectrometry.

    PubMed

    Hites, Ronald A

    2016-07-19

    Gas chromatographic mass spectrometry is now widely used for the quantitation and identification of organic compounds in almost any imaginable sample. These applications include the measurement of chlorinated dioxins in soil samples, the identification of illicit drugs in human blood, and the quantitation of accelerants in arson investigations, to name just a few. How did GC/MS get so popular? It turns out that it required parallel developments in mass spectrometry, gas chromatography, and computing and that no one person "invented" the technique. This Perspective traces this history from the 1950s until today. PMID:27384908

  16. New Types of Ionization Sources for Mass Spectrometry

    SciTech Connect

    2008-12-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle (Contractor) and MDS Sciex (Participant) and ESA, Inc. (Participant) is to research, develop and apply new types of ionization sources and sampling/inlet systems for analytical mass spectrometry making use of the Participants state-of-the-art atmospheric sampling mass spectrometry electrochemical cell technology instrumentation and ancillary equipment. The two overriding goals of this research project are: to understand the relationship among the various instrumental components and operational parameters of the various ion sources and inlet systems under study, the chemical nature of the gases, solvents, and analytes in use, and the nature and abundances of the ions ultimately observed in the mass spectrometer; and to develop new and better analytical and fundamental applications of these ion sources and inlet systems or alternative sources and inlets coupled with mass spectrometry on the basis of the fundamental understanding obtained in Goal 1. The end results of this work are expected to be: (1) an expanded utility for the ion sources and inlet systems under study (such as the analysis of new types of analytes) and the control or alteration of the ionic species observed in the gas-phase; (2) enhanced instrument performance as judged by operational figures-of-merit such as dynamic range, detection limits, susceptibility to matrix signal suppression and sensitivity; and (3) novel applications (such as surface sampling with electrospray) in both applied and fundamental studies. The research projects outlined herein build upon work initiated under the previous CRADA between the Contractor and MDS Sciex on ion sources and inlet systems for mass spectrometry. Specific ion source and inlet systems for exploration of the fundamental properties and practical implementation of these principles are given.

  17. Exploring the high-mass components of humic acid by laser desorption ionization mass spectrometry.

    PubMed

    Chilom, Gabriela; Chilom, Ovidiu; Rice, James A

    2008-05-01

    Leonardite and Elliot soil humic acids have been analyzed by laser desorption ionization mass spectrometry (LDI MS) in the m/z 4000-200,000 range. Positive ion mass spectra for each humic acid obtained under optimum conditions showed a broad high-mass distribution between m/z 20,000 and 80,000. The dependence of the mass distribution on instrumental parameters and solution conditions was used to investigate the nature of the high-mass peaks from humic acid spectra. Our data suggests that macromolecular ions and humic acid aggregates have the same probability of occurrence while cluster ion formation has a low probability of occurrence. PMID:18421699

  18. Fast Atom Bombardment Mass Spectrometry.

    ERIC Educational Resources Information Center

    Rinehart, Kenneth L., Jr.

    1982-01-01

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

  19. Targeted quantitation of proteins by mass spectrometry.

    PubMed

    Liebler, Daniel C; Zimmerman, Lisa J

    2013-06-01

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

  20. Mass spectrometry in the home and garden.

    PubMed

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

    2015-02-01

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application. PMID:25510934

  1. Continuous Simultaneous Detection in Mass Spectrometry

    SciTech Connect

    Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.; Sperline, Roger P.; Denton, M. Bonner; Barinaga, Charles J.; Koppenaal, David W.; Hieftje, Gary M.

    2007-10-15

    In mass spectrometry, several advantages can be derived when multiple mass-to-charge values are detected simultaneously. One such advantage is an improved duty cycle, which leads to superior limits of detection, better precision, shorter analysis times, and reduced sample sizes. A second advantage is the ability to reduce correlated noise by taking the ratio of two or more simultaneously collected signals, enabling greatly enhanced isotope ratio data. A final advantage is the elimination of spectral skew, leading to more accurate transient signal analysis. Here, these advantages are demonstrated by means of a novel Faraday-strip array detector coupled to a Mattauch-Herzog mass spectrograph. The same system is used to monitor elemental fractionation phenomena in laser ablation inductively coupled plasma mass spectrometry.

  2. Colloquium: 100 years of mass spectrometry: Perspectives and future trends

    NASA Astrophysics Data System (ADS)

    Maher, Simon; Jjunju, Fred P. M.; Taylor, Stephen

    2015-01-01

    Mass spectrometry (MS) is widely regarded as the most sensitive and specific general purpose analytical technique. More than a century has passed for MS since the ground-breaking work of Nobel laureate Sir Joseph John Thomson in 1913. This Colloquium aims to (1) give an historical overview of the major instrumentation achievements that have driven mass spectrometry forward in the past century, including those leading up to the initial work of Thomson, (2) provide the nonspecialist with an introduction to MS, and (3) highlight some key applications of MS and explore the current and future trends. Because of the vastness of the subject area and quality of the manifold research efforts that have been undertaken over the last 100 years, which have contributed to the foundations and subsequent advances in mass spectrometry, it should be understood that not all of the key contributions may have been included in this Colloquium. Mass spectrometry has embraced a multitude of scientific disciplines and to recognize all of the achievements is an impossible task, such has been the diverse impact of this invaluable technique. Scientific progress is usually made via the cumulative effort of a large number of researchers; the achievements reported herein are only a representation of that effort.

  3. Atmospheric pressure femtosecond laser imaging mass spectrometry

    NASA Astrophysics Data System (ADS)

    Coello, Yves; Gunaratne, Tissa C.; Dantus, Marcos

    2009-02-01

    We present a novel imaging mass spectrometry technique that uses femtosecond laser pulses to directly ionize the sample. The method offers significant advantages over current techniques by eliminating the need of a laser-absorbing sample matrix, being suitable for atmospheric pressure sampling, and by providing 10μm resolution, as demonstrated here with a chemical image of vegetable cell walls.

  4. Accelerator mass spectrometry with heavy ions

    NASA Astrophysics Data System (ADS)

    Haberstock, Günther; Heinzl, Johann; Korschinek, Gunther; Morinaga, Haruhiko; Nolte, Eckehart; Ratzinger, Ulrich; Kato, Kazuo; Wolf, Manfred

    1986-11-01

    Accelerator mass spectrometry measurements with fully stripped 36Cl ions have been performed at the Munich accelerator laboratory in order to date groundwaters and palaeontological samples, to study anthropogenic 36Cl produced through nuclear tests and to determine the fast neutron flux of the Hiroshima A-bomb.

  5. Nanostructure-initiator mass spectrometry biometrics

    DOEpatents

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

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

  6. Pyrolysis Mass Spectrometry of Complex Organic Materials.

    ERIC Educational Resources Information Center

    Meuzelaar, Henk L. C.; And Others

    1984-01-01

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

  7. Optimization Of A Mass Spectrometry Process

    SciTech Connect

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

    2011-06-01

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

  8. Application of Laser Mass Spectrometry to Art and Archaeology

    NASA Technical Reports Server (NTRS)

    Gulian, Lase Lisa E.; Callahan, Michael P.; Muliadi, Sarah; Owens, Shawn; McGovern, Patrick E.; Schmidt, Catherine M.; Trentelman, Karen A.; deVries, Mattanjah S.

    2011-01-01

    REMPI laser mass spectrometry is a combination of resonance enhanced multiphoton ionization spectroscopy and time of flight mass spectrometry, This technique enables the collection of mass specific optical spectra as well as of optically selected mass spectra. Analytes are jet-cooled by entrainment in a molecular beam, and this low temperature gas phase analysis has the benefit of excellent vibronic resolution. Utilizing this method, mass spectrometric analysis of historically relevant samples can be simplified and improved; Optical selection of targets eliminates the need for chromatography while knowledge of a target's gas phase spectroscopy allows for facile differentiation of molecules that are in the aqueous phase considered spectroscopically indistinguishable. These two factors allow smaller sample sizes than commercial MS instruments, which in turn will require less damage to objects of antiquity. We have explored methods to optimize REMPI laser mass spectrometry as an analytical tool to archaeology using theobromine and caffeine as molecular markers in Mesoamerican pottery, and are expanding this approach to the field of art to examine laccaic acid in shellacs.

  9. Lipidomic mass spectrometry and its application in neuroscience

    PubMed Central

    Enriquez-Algeciras, Mabel; Bhattacharya, Sanjoy K

    2013-01-01

    Central and peripheral nervous systems are lipid rich tissues. Lipids, in the context of lipid-protein complexes, surround neurons and provide electrical insulation for transmission of signals allowing neurons to remain embedded within a conducting environment. Lipids play a key role in vesicle formation and fusion in synapses. They provide means of rapid signaling, cell motility and migration for astrocytes and other cell types that surround and play supporting roles neurons. Unlike many other signaling molecules, lipids are capable of multiple signaling events based on the different fragments generated from a single precursor during each event. Lipidomics, until recently suffered from two major disadvantages: (1) level of expertise required an overwhelming amount of chemical detail to correctly identify a vast number of different lipids which could be close in their chemical reactivity; and (2) high amount of purified compounds needed by analytical techniques to determine their structures. Advances in mass spectrometry have enabled overcoming these two limitations. Mass spectrometry offers a great degree of simplicity in identification and quantification of lipids directly extracted from complex biological mixtures. Mass spectrometers can be regarded to as mass analyzers. There are those that separate and analyze the product ion fragments in space (spatial) and those which separate product ions in time in the same space (temporal). Databases and standardized instrument parameters have further aided the capabilities of the spatial instruments while recent advances in bioinformatics have made the identification and quantification possible using temporal instruments. PMID:24340133

  10. Membrane introduction mass spectrometry: trends and applications.

    PubMed

    Johnson, R C; Cooks, R G; Allen, T M; Cisper, M E; Hemberger, P H

    2000-01-01

    Recent advances in membrane introduction mass spectrometry (MIMS) are reviewed. On-line monitoring is treated by focusing on critical variables, including the nature and dimensions of the membrane, and the analyte vapor pressure, diffusivity, and solubility in the membrane barrier. Sample introduction by MIMS is applied in (i) on-line monitoring of chemical and biological reactors, (ii) analysis of volatile organic compounds in environmental matrices, including air, water and soil, and (iii) in more fundamental studies, such as measurements of thermochemical properties, reaction mechanisms, and kinetics. New semipermeable membranes are discussed, including those consisting of thin polymers, low vapor pressure liquids, and zeolites. These membranes have been used to monitor polar compounds, selectively differentiate compounds through affinity-binding, and provide isomer differentiation based on molecular size. Measurements at high spatial resolution, for example, using silicone-capped hypodermic needle inlets, are also covered, as is electrically driven sampling through microporous membranes. Other variations on the basic MIMS experiment include analyte preconcentration through cryotrapping (CT-MIMS) or trapping in the membrane (trap-and-release), as well as differential thermal release methods and reverse phase (i.e., organic solvent) MIMS. Method limitations center on semivolatile compounds and complex mixture analysis, and novel solutions are discussed. Semivolatile compounds have been monitored with thermally assisted desorption, ultrathin membranes and derivatization techniques. Taking advantage of the differences in time of membrane permeation, mixtures of structurally similar compounds have been differentiated by using sample modulation techniques and by temperature-programmed desorption from a membrane interface. Selective ionization techniques that increase instrument sensitivity towards polar compounds are also described, and comparisons are made with

  11. POTAMOS mass spectrometry calculator: computer aided mass spectrometry to the post-translational modifications of proteins. A focus on histones.

    PubMed

    Vlachopanos, A; Soupsana, E; Politou, A S; Papamokos, G V

    2014-12-01

    Mass spectrometry is a widely used technique for protein identification and it has also become the method of choice in order to detect and characterize the post-translational modifications (PTMs) of proteins. Many software tools have been developed to deal with this complication. In this paper we introduce a new, free and user friendly online software tool, named POTAMOS Mass Spectrometry Calculator, which was developed in the open source application framework Ruby on Rails. It can provide calculated mass spectrometry data in a time saving manner, independently of instrumentation. In this web application we have focused on a well known protein family of histones whose PTMs are believed to play a crucial role in gene regulation, as suggested by the so called "histone code" hypothesis. The PTMs implemented in this software are: methylations of arginines and lysines, acetylations of lysines and phosphorylations of serines and threonines. The application is able to calculate the kind, the number and the combinations of the possible PTMs corresponding to a given peptide sequence and a given mass along with the full set of the unique primary structures produced by the possible distributions along the amino acid sequence. It can also calculate the masses and charges of a fragmented histone variant, which carries predefined modifications already implemented. Additional functionality is provided by the calculation of the masses of fragments produced upon protein cleavage by the proteolytic enzymes that are most widely used in proteomics studies. PMID:25450216

  12. Trends in biochemical and biomedical applications of mass spectrometry

    NASA Astrophysics Data System (ADS)

    Gelpi, Emilio

    1992-09-01

    This review attempts an in-depth evaluation of progress and achievements made since the last 11th International Mass Spectrometry Conference in the application of mass spectrometric techniques to biochemistry and biomedicine. For this purpose, scientific contributions in this field at major international meetings have been monitored, together with an extensive appraisal of literature data covering the period from 1988 to 1991. A bibliometric evaluation of the MEDLINE database for this period provides a total of almost 4000 entries for mass spectrometry. This allows a detailed study of literature and geographical sources of the most frequent applications, of disciplines where mass spectrometry is most active and of types of sample and instrumentation most commonly used. In this regard major efforts according to number of publications (over 100 literature reports) are concentrated in countries like Canada, France, Germany, Italy, Japan, Sweden, UK and the USA. Also, most of the work using mass spectrometry in biochemistry and biomedicine is centred on studies on biotransformation, metabolism, pharmacology, pharmacokinetics and toxicology, which have been carried out on samples of blood, urine, plasma and tissue, by order of frequency of use. Human and animal studies appear to be evenly distributed in terms of the number of reports published in the literature in which the authors make use of experimental animals or describe work on human samples. Along these lines, special attention is given to the real usefulness of mass spectrometry (MS) technology in routine medical practice. Thus the review concentrates on evaluating the progress made in disease diagnosis and overall patient care. As regards prevailing techniques, GCMS continues to be the mainstay of the state of the art methods for multicomponent analysis, stable isotope tracer studies and metabolic profiling, while HPLC--MS and tandem MS are becoming increasingly important in biomedical research. However

  13. Mass Spectrometry for Planetary Probes: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Niemann, Hasso B.; Harpold, Dan N.; Jamieson, Brian G.; Mahaffy, Paul R.

    2005-01-01

    Atmospheric entry probes present a unique opportunity for performing quantitative analysis of extra-terrestrial atmospheres in cases where remote sensing alone may not be sufficient and measurements with balloons or aircraft is not practical. An entry probe can provide a complete vertical profile of atmospheric parameters including chemical composition, which cannot be obtained with most other techniques. There are, however, unique challenges associated with building instruments for an entry probe, as compared to orbiters, landers, or rovers. Conditions during atmospheric entry are extreme, there are inherent time constraints due to the short duration of the experiment, and the instrument experiences rapid environmental changes in temperature and pressure as it descends. In addition, there are resource limitations, i.e. mass, power, size and bandwidth. Finally, the demands on the instrument design are determined in large part by conditions (pressure, temperature, composition) unique to the particular body under study, and as a result there is no one-size-fits-all instrument for an atmospheric probe. Many of these requirements can be more easily met by miniaturizing the probe instrument. Our experience building mass spectrometers for atmospheric entry probes leads us to believe that the time is right for a fundamental change in the way spaceflight mass spectrometers are built. The emergence over the past twenty years of Micro-electro- mechanical Systems (MEMS), utilizing lithographic semiconductor fabrication techniques to produce instrument systems in miniature, holds great promise for application to spaceflight mass spectrometry. A highly miniaturized, high performance and low-power mass spectrometer would be an enormous benefit to future entry probe missions, allowing, for example, parallel measurements (e.g., multiple simultaneous gas chromatographic analyses and direct atmospheric leaks.) Such an instrument would also enable mass spectrometry on board small

  14. Analytical validation of accelerator mass spectrometry for pharmaceutical development

    PubMed Central

    Keck, Bradly D; Ognibene, Ted; Vogel, John S

    2011-01-01

    The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of 14C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the 14C label), stable across samples storage conditions for at least 1 year, linear over four orders of magnitude with an analytical range from 0.1 Modern to at least 2000 Modern (instrument specific). Furthermore, accuracy was excellent (between 1 and 3%), while precision expressed as coefficient of variation was between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of 14C, respectively (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with 14C corresponds to 30 fg equivalents. Accelerator mass spectrometry provides a sensitive, accurate and precise method of measuring drug compounds in biological matrices. PMID:21083256

  15. Analytical considerations for mass spectrometry profiling in serum biomarker discovery.

    PubMed

    Whiteley, Gordon R; Colantonio, Simona; Sacconi, Andrea; Saul, Richard G

    2009-03-01

    The potential of using mass spectrometry profiling as a diagnostic tool has been demonstrated for a wide variety of diseases. Various cancers and cancer-related diseases have been the focus of much of this work because of both the paucity of good diagnostic markers and the knowledge that early diagnosis is the most powerful weapon in treating cancer. The implementation of mass spectrometry as a routine diagnostic tool has proved to be difficult, however, primarily because of the stringent controls that are required for the method to be reproducible. The method is evolving as a powerful guide to the discovery of biomarkers that could, in turn, be used either individually or in an array or panel of tests for early disease detection. Using proteomic patterns to guide biomarker discovery and the possibility of deployment in the clinical laboratory environment on current instrumentation or in a hybrid technology has the possibility of being the early diagnosis tool that is needed. PMID:19389551

  16. Native Mass Spectrometry in Fragment-Based Drug Discovery.

    PubMed

    Pedro, Liliana; Quinn, Ronald J

    2016-01-01

    The advent of native mass spectrometry (MS) in 1990 led to the development of new mass spectrometry instrumentation and methodologies for the analysis of noncovalent protein-ligand complexes. Native MS has matured to become a fast, simple, highly sensitive and automatable technique with well-established utility for fragment-based drug discovery (FBDD). Native MS has the capability to directly detect weak ligand binding to proteins, to determine stoichiometry, relative or absolute binding affinities and specificities. Native MS can be used to delineate ligand-binding sites, to elucidate mechanisms of cooperativity and to study the thermodynamics of binding. This review highlights key attributes of native MS for FBDD campaigns. PMID:27483215

  17. Investigating quantitation of phosphorylation using MALDI-TOF mass spectrometry

    PubMed Central

    Parker, Laurie; Engel-Hall, Aaron; Drew, Kevin; Steinhardt, George; Helseth, Donald L.; Jabon, David; McMurry, Timothy; Angulo, David S.; Kron, Stephen J.

    2010-01-01

    Despite advances in methods and instrumentation for analysis of phosphopeptides using mass spectrometry, it is still difficult to quantify the extent of phosphorylation of a substrate due to physiochemical differences between unphosphorylated and phosphorylated peptides. Here we report experiments to investigate those differences using MALDI-TOF mass spectrometry for a set of synthetic peptides by creating calibration curves of known input ratios of peptides/phosphopeptides and analyzing their resulting signal intensity ratios. These calibration curves reveal subtleties in sequence-dependent differences for relative desorption/ionization efficiencies that cannot be seen from single-point calibrations. We found that the behaviors were reproducible with a variability of 5–10% for observed phosphopeptide signal. Although these data allow us to begin addressing the issues related to modeling these properties and predicting relative signal strengths for other peptide sequences, it is clear this behavior is highly complex and needs to be further explored. PMID:18064576

  18. Linking Mass Spectrometry with Toxicology for Emerging Water Contaminants

    EPA Science Inventory

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

  19. Laser-desorption mass spectrometry/mass spectrometry and the mechanism of desorption ionization

    SciTech Connect

    Zakett, D.; Schoen, A.E.; Cooks, R.G.; Hemberger, P.H.

    1981-03-11

    This paper reports sucrose mass spectra obtained by combining laser desorption with mass spectrometry/mass spectrometry. Remarkable similarities in fragmentation behavior with secondary ion mass spectra (SIMS) provide evidence for mechanistic similarities between SIMS and laser desorption (LD). Attachment of alkali metals to organic molecules (cationization) is a common feature of desorption ionization. This process also occurs during laser desorption of involatile compounds which further indicates the existence of underlying similarities between LD and SIMS. Steady ion currents (several thousand ions per laser pulse) of cationized sucrose are obtained for relatively long periods (minutes).

  20. High resolution laser mass spectrometry bioimaging.

    PubMed

    Murray, Kermit K; Seneviratne, Chinthaka A; Ghorai, Suman

    2016-07-15

    Mass spectrometry imaging (MSI) was introduced more than five decades ago with secondary ion mass spectrometry (SIMS) and a decade later with laser desorption/ionization (LDI) mass spectrometry (MS). Large biomolecule imaging by matrix-assisted laser desorption/ionization (MALDI) was developed in the 1990s and ambient laser MS a decade ago. Although SIMS has been capable of imaging with a moderate mass range at sub-micrometer lateral resolution from its inception, laser MS requires additional effort to achieve a lateral resolution of 10μm or below which is required to image at the size scale of single mammalian cells. This review covers untargeted large biomolecule MSI using lasers for desorption/ionization or laser desorption and post-ionization. These methods include laser microprobe (LDI) MSI, MALDI MSI, laser ambient and atmospheric pressure MSI, and near-field laser ablation MS. Novel approaches to improving lateral resolution are discussed, including oversampling, beam shaping, transmission geometry, reflective and through-hole objectives, microscope mode, and near-field optics. PMID:26972785

  1. Mass Spectrometry Imaging under Ambient Conditions

    PubMed Central

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

    2012-01-01

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

  2. Ion-molecule adduct formation in tandem mass spectrometry.

    PubMed

    Alechaga, Élida; Moyano, Encarnación; Galceran, Maria Teresa

    2016-02-01

    Nowadays most LC-MS methods rely on tandem mass spectrometry not only for quantitation and confirmation of compounds by multiple reaction monitoring (MRM), but also for the identification of unknowns from their product ion spectra. However, gas-phase reactions between charged and neutral species inside the mass analyzer can occur, yielding product ions at m/z values higher than that of the precursor ion, or at m/z values difficult to explain by logical losses, which complicate mass spectral interpretation. In this work, the formation of adduct ions in the mass analyzer was studied using several mass spectrometers with different mass analyzers (ion trap, triple quadrupole, and quadrupole-Orbitrap). Heterocyclic amines (AαC, MeAαC, Trp-P-1, and Trp-P-2), photo-initiators (BP and THBP), and pharmaceuticals (phenacetin and levamisole) were selected as model compounds and infused in LCQ Classic, TSQ Quantum Ultra AM, and Q-Exactive Orbitrap (ThermoFisher Scientific) mass spectrometers using electrospray as ionization method. The generation of ion-molecule adducts depended on the compound and also on the instrument employed. Adducts with neutral organic solvents (methanol and acetonitrile) were only observed in the ion trap instrument (LCQ Classic), because of the ionization source on-axis configuration and the lack of gas-phase barriers, which allowed inertial entrance of the neutrals into the analyzer. Adduct formation (only with water) in the triple quadrupole instruments was less abundant than in the ion trap and quadrupole-Orbitrap mass spectrometers, because of the lower residence time of the reactive product ions in the mass analyzer. The moisture level of the CID and/or damper gas had a great effect in beam-like mass analyzers such as triple quadrupole, but not in trap-like mass analyzers, probably because of the long residence time that allowed adduct formation even with very low concentrations of water inside the mass spectrometer. PMID:26700446

  3. Choosing between high-resolution mass spectrometry and mass spectrometry/mass spectrometry: Environmental applications

    SciTech Connect

    Charles, M.J. ); Tondeur, Y. )

    1990-12-01

    Selectivity in environmental analyses requires the use of fractionation techniques and HRMS or MS/MS to eliminate specific and nonspecific interferences. In the analysis of TCDDs and TCDFs, HRMS is the method of choice when specific interferences arising from compounds with molecular or fragment ions can be separated from TCDD and TCDF ions at a resolving power of 10,000. In cases where HRMS does not provide adequate selectivity at this resolving power, MS/MS is needed. Analyses on a pulp and paper effluent extract show that MS/MS was able to substantially eliminate interferences due to the presence of methyl and ethyl tetrachlorinated dibenzofurans that were not removed by HRMS at resolving powers of 10,000 and 18,000. Nonspecific interferences may also be present due to coelution of compounds that cause changes in the response of the mass spectrometer and are best eliminated by fractionation techniques or by altering conditions of analyses.

  4. Laser-Cooling-Assisted Mass Spectrometry

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  5. Mass spectrometry in Chronic Kidney Disease research

    PubMed Central

    Merchant, Michael L.

    2010-01-01

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

  6. Storage-Ring Mass Spectrometry in Japan

    NASA Astrophysics Data System (ADS)

    Suzaki, Fumi; Yamaguchi, Takayuki

    Atomic masses are a fundamental ground-state property of nuclei, reflecting a wide variety of structures and dynamics among nucleons. High-precision mass values of short-lived, in particular neutron-rich, nuclei are a key issue toward full understanding of astrophysical nucleosynthesis, as well as nuclear shell evolution far from stability. Beyond the precision mass measurements performed at worldwide ion-trap facilities, a new method of storage-ring mass spectrometry is now being developed at the RIKEN RI Beam Factory in Japan. Combined with the highest intensities of intermediate-energy radioactive ion beams currently available through in-flight separation of uranium fission products, the present method will enable us to measure the masses of extremely neutron-rich, rare species located on the r-process pathway, with a tiny yield (as low as ~1 counts/day).

  7. Order of Magnitude Signal Gain in Magnetic Sector Mass Spectrometry Via Aperture Coding

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    Miniaturizing instruments for spectroscopic applications requires the designer to confront a tradeoff between instrument resolution and instrument throughput [and associated signal-to-background-ratio (SBR)]. This work demonstrates a solution to this tradeoff in sector mass spectrometry by the first application of one-dimensional (1D) spatially coded apertures, similar to those previously demonstrated in optics. This was accomplished by replacing the input slit of a simple 90° magnetic sector mass spectrometer with a specifically designed coded aperture, deriving the corresponding forward mathematical model and spectral reconstruction algorithm, and then utilizing the resulting system to measure and reconstruct the mass spectra of argon, acetone, and ethanol. We expect the application of coded apertures to sector instrument designs will lead to miniature mass spectrometers that maintain the high performance of larger instruments, enabling field detection of trace chemicals and point-of-use mass spectrometry.

  8. Antibodies as means for selective mass spectrometry.

    PubMed

    Boström, Tove; Takanen, Jenny Ottosson; Hober, Sophia

    2016-05-15

    For protein analysis of biological samples, two major strategies are used today; mass spectrometry (MS) and antibody-based methods. Each strategy offers advantages and drawbacks. However, combining the two using an immunoenrichment step with MS analysis brings together the benefits of each method resulting in increased sensitivity, faster analysis and possibility of higher degrees of multiplexing. The immunoenrichment can be performed either on protein or peptide level and quantification standards can be added in order to enable determination of the absolute protein concentration in the sample. The combination of immunoenrichment and MS holds great promise for the future in both proteomics and clinical diagnostics. This review describes different setups of immunoenrichment coupled to mass spectrometry and how these can be utilized in various applications. PMID:26565067

  9. Mass spectrometry imaging for biomedical applications

    PubMed Central

    Liu, Jiangjiang; Ouyang, Zheng

    2013-01-01

    The development of mass spectrometry imaging technologies is of significant current research interest. Mass spectrometry potentially is capable of providing highly specific information about the distribution of chemical compounds on tissues at highly sensitive levels. The required in-situ analysis for the tissue imaging forced MS analysis being performed off the traditional conditions optimized in pharmaceutical applications with intense sample preparation. This critical review seeks to present an overview of the current status of the MS imaging with different sampling ionization methods and to discuss the 3D imaging and quantitative imaging capabilities needed to be further developed, the importance of the multi-modal imaging, and a balance between the pursuit of the high imaging resolution and the practical application of MS imaging in biomedicine. PMID:23539099

  10. Spatial neuroproteomics using imaging mass spectrometry.

    PubMed

    Hanrieder, Jörg; Malmberg, Per; Ewing, Andrew G

    2015-07-01

    The nervous system constitutes arguably the most complicated and least understood cellular network in the human body. This consequently manifests itself in the fact that the molecular bases of neurodegenerative diseases remain unknown. The limited understanding of neurobiological mechanisms relates directly to the lack of appropriate bioanalytical technologies that allow highly resolved, sensitive, specific and comprehensive molecular imaging in complex biological matrices. Imaging mass spectrometry (IMS) is an emerging technique for molecular imaging. The technique is characterized by its high chemical specificity allowing comprehensive, spatial protein and peptide profiling in situ. Imaging MS represents therefore a powerful approach for investigation of spatio-temporal protein and peptide regulations in CNS derived tissue and cells. This review aims to provide a concise overview of major developments and applications concerning imaging mass spectrometry based protein and peptide profiling in neurobiological and biomedical research. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology. PMID:25582083

  11. Biomarker Signature Discovery from Mass Spectrometry Data.

    PubMed

    Kong, Ao; Gupta, Chinmaya; Ferrari, Mauro; Agostini, Marco; Bedin, Chiara; Bouamrani, Ali; Tasciotti, Ennio; Azencott, Robert

    2014-01-01

    Mass spectrometry based high throughput proteomics are used for protein analysis and clinical diagnosis. Many machine learning methods have been used to construct classifiers based on mass spectrometry data, for discrimination between cancer stages. However, the classifiers generated by machine learning such as SVM techniques typically lack biological interpretability. We present an innovative technique for automated discovery of signatures optimized to characterize various cancer stages. We validate our signature discovery algorithm on one new colorectal cancer MALDI-TOF data set, and two well-known ovarian cancer SELDI-TOF data sets. In all of these cases, our signature based classifiers performed either better or at least as well as four benchmark machine learning algorithms including SVM and KNN. Moreover, our optimized signatures automatically select smaller sets of key biomarkers than the black-boxes generated by machine learning, and are much easier to interpret. PMID:26356346

  12. High-sensitivity mass spectrometry with a tandem accelerator

    SciTech Connect

    Henning, W.

    1983-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems.

  13. A Mass Spectrometry Proteomics Data Management Platform*

    PubMed Central

    Sharma, Vagisha; Eng, Jimmy K.; MacCoss, Michael J.; Riffle, Michael

    2012-01-01

    Mass spectrometry-based proteomics is increasingly being used in biomedical research. These experiments typically generate a large volume of highly complex data, and the volume and complexity are only increasing with time. There exist many software pipelines for analyzing these data (each typically with its own file formats), and as technology improves, these file formats change and new formats are developed. Files produced from these myriad software programs may accumulate on hard disks or tape drives over time, with older files being rendered progressively more obsolete and unusable with each successive technical advancement and data format change. Although initiatives exist to standardize the file formats used in proteomics, they do not address the core failings of a file-based data management system: (1) files are typically poorly annotated experimentally, (2) files are “organically” distributed across laboratory file systems in an ad hoc manner, (3) files formats become obsolete, and (4) searching the data and comparing and contrasting results across separate experiments is very inefficient (if possible at all). Here we present a relational database architecture and accompanying web application dubbed Mass Spectrometry Data Platform that is designed to address the failings of the file-based mass spectrometry data management approach. The database is designed such that the output of disparate software pipelines may be imported into a core set of unified tables, with these core tables being extended to support data generated by specific pipelines. Because the data are unified, they may be queried, viewed, and compared across multiple experiments using a common web interface. Mass Spectrometry Data Platform is open source and freely available at http://code.google.com/p/msdapl/. PMID:22611296

  14. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

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

    2011-09-20

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

  15. Mass Spectrometry in Plant-omics.

    PubMed

    Gemperline, Erin; Keller, Caitlin; Li, Lingjun

    2016-04-01

    Plant-omics is rapidly becoming an important field of study in the scientific community due to the urgent need to address many of the most important questions facing humanity today with regard to agriculture, medicine, biofuels, environmental decontamination, ecological sustainability, etc. High-performance mass spectrometry is a dominant tool for interrogating the metabolomes, peptidomes, and proteomes of a diversity of plant species under various conditions, revealing key insights into the functions and mechanisms of plant biochemistry. PMID:26889688

  16. Dissecting SUMO Dynamics by Mass Spectrometry.

    PubMed

    Drabikowski, Krzysztof; Dadlez, Michał

    2016-01-01

    Protein modification by SUMO proteins is one of the key posttranslational modifications in eukaryotes. Here, we describe a workflow to analyze SUMO dynamics in response to different stimuli, purify SUMO conjugates, and analyze the changes in SUMOylation level in organisms, tissues, or cell culture. We present a protocol for lysis in denaturing conditions that is compatible with downstream IMAC and antibody affinity purification, followed by mass spectrometry and data analysis. PMID:27613044

  17. Advances in 193 nm excimer lasers for mass spectrometry applications

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

    2016-03-01

    Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

  18. High-speed, high-resolution, multielemental laser ablation-inductively coupled plasma-time-of-flight mass spectrometry imaging: part I. Instrumentation and two-dimensional imaging of geological samples.

    PubMed

    Gundlach-Graham, Alexander; Burger, Marcel; Allner, Steffen; Schwarz, Gunnar; Wang, Hao A O; Gyr, Luzia; Grolimund, Daniel; Hattendorf, Bodo; Günther, Detlef

    2015-08-18

    Low-dispersion laser ablation (LA) has been combined with inductively coupled plasma-time-of-flight mass spectrometry (ICP-TOFMS) to provide full-spectrum elemental imaging at high lateral resolution and fast image-acquisition speeds. The low-dispersion LA cell reported here is capable of delivering 99% of the total LA signal within 9 ms, and the prototype TOFMS instrument enables simultaneous and representative determination of all elemental ions from these fast-transient ablation events. This fast ablated-aerosol transport eliminates the effects of pulse-to-pulse mixing at laser-pulse repetition rates up to 100 Hz. Additionally, by boosting the instantaneous concentration of LA aerosol into the ICP with the use of a low-dispersion ablation cell, signal-to-noise (S/N) ratios, and thus limits of detection (LODs), are improved for all measured isotopes; the lowest LODs are in the single digit parts per million for single-shot LA signal from a 10-μm diameter laser spot. Significantly, high-sensitivity, multielemental and single-shot-resolved detection enables the use of small LA spot sizes to improve lateral resolution and the development of single-shot quantitative imaging, while also maintaining fast image-acquisition speeds. Here, we demonstrate simultaneous elemental imaging of major and minor constituents in an Opalinus clay-rock sample at a 1.5 μm laser-spot diameter and quantitative imaging of a multidomain Pallasite meteorite at a 10 μm LA-spot size. PMID:26122331

  19. Extending the frontiers of mass spectrometric instrumentation and methods

    SciTech Connect

    Schieffer, Gregg Martin

    2010-01-01

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

  20. Resolution of time-of-flight mass spectrometers evaluated for secondary neutral mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kato, Makoto; Mogami, Akinori; Naito, Motohiro; Ichimura, Shingo; Shimizu, Hazime

    1988-09-01

    Mass resolution of a time-of-flight mass spectrometer with a two-stage electrostatic reflector is calculated for secondary neutral mass spectrometry. The instrument parameters are optimized for energy and space focusing: correcting the flight time difference due to the energy width ΔE of sputtered particles and the spatial width Δs of an ionizing laser beam. The effect of Δs can be compensated by applying an acceleration field to the ionizing region, and the maximum resolution becomes about 1000 for ΔE=10 eV and Δs=1.0 mm.

  1. Application of a quadrupole mass filter to laser ionization mass spectrometry: synchronization between the laser pulse and the mass scan

    NASA Astrophysics Data System (ADS)

    Kuzuya, M.; Ohoka, Y.; Katoh, H.; Sakanashi, H.

    1998-01-01

    A quadrupole-based laser ionization mass spectrometry system was developed by combining a commercial quadrupole mass filter with a laser microprobe instrument, which employs a pulse generator that synchronizes the laser pulse with the quadrupole mass scan to detect the pulsed ion signals generated by laser induced ionization. Mass spectra were measured for several solid samples of pure metals (Al,Cu), metal alloys (Inconel 601, brass), and ceramics (BN). Reproducible spectra, with relative standard deviations of the ion signals less than 1%, were obtained with this system. Moreover, isotope abundance ratios were measured and compared with the natural abundance ratios.

  2. Structurally selective imaging mass spectrometry by imaging ion mobility-mass spectrometry.

    PubMed

    McLean, John A; Fenn, Larissa S; Enders, Jeffrey R

    2010-01-01

    This chapter describes the utility of structurally based separations combined with imaging mass spectrometry (MS) by ion mobility-MS (IM-MS) approaches. The unique capabilities of combining rapid (mus-ms) IM separations with imaging MS are detailed for an audience ranging from new to potential practitioners in IM-MS technology. Importantly, imaging IM-MS provides the ability to rapidly separate and elucidate various types of endogenous and exogenous biomolecules (e.g., nucleotides, carbohydrates, peptides, and lipids), including isobaric species. Drift tube and traveling wave IM-MS instrumentation are described and specific protocols are presented for calculating ion-neutral collision cross sections (i.e., apparent ion surface area or structure) from experimentally obtained IM-MS data. Special emphasis is placed on the use of imaging IM-MS for the analysis of samples in life sciences research (e.g., thin tissue sections), including selective imaging for peptide/protein and lipid distributions. Future directions for rapid and multiplexed imaging IM-MS/MS are detailed. PMID:20680602

  3. Laser desorption postionization mass spectrometry imaging of biological targets.

    PubMed

    Akhmetov, Artem; Bhardwaj, Chhavi; Hanley, Luke

    2015-01-01

    Laser desorption photoionization mass spectrometry (LDPI-MS) utilizes two separate light sources for desorption and photoionization of species from a solid surface. This technique has been applied to study a wide variety of molecular analytes in biological systems, but is not yet available in commercial instruments. For this reason, a generalized protocol is presented here for the use of LDPI-MS imaging to detect small molecules within intact biological samples. Examples are provided here for LDPI-MS imaging of an antibiotic within a tooth root canal and a metabolite within a coculture bacterial biofilm. PMID:25361678

  4. Definition of the limit of quantification in the presence of instrumental and non-instrumental errors. Comparison among various definitions applied to the calibration of zinc by inductively coupled plasma-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Favaro, Gabriella; Pastore, Paolo

    2015-12-01

    The limit of quantification (LOQ) in the presence of instrumental and non-instrumental errors was proposed. It was theoretically defined combining the two-component variance regression and LOQ schemas already present in the literature and applied to the calibration of zinc by the ICP-MS technique. At low concentration levels, the two-component variance LOQ definition should be always used above all when a clean room is not available. Three LOQ definitions were accounted for. One of them in the concentration and two in the signal domain. The LOQ computed in the concentration domain, proposed by Currie, was completed by adding the third order terms in the Taylor expansion because they are of the same order of magnitude of the second ones so that they cannot be neglected. In this context, the error propagation was simplified by eliminating the correlation contributions by using independent random variables. Among the signal domain definitions, a particular attention was devoted to the recently proposed approach based on at least one significant digit in the measurement. The relative LOQ values resulted very large in preventing the quantitative analysis. It was found that the Currie schemas in the signal and concentration domains gave similar LOQ values but the former formulation is to be preferred as more easily computable.

  5. Advances in Mass Spectrometry for Lipidomics

    NASA Astrophysics Data System (ADS)

    Blanksby, Stephen J.; Mitchell, Todd W.

    2010-07-01

    Recent expansion in research in the field of lipidomics has been driven by the development of new mass spectrometric tools and protocols for the identification and quantification of molecular lipids in complex matrices. Although there are similarities between the field of lipidomics and the allied field of mass spectrometry (e.g., proteomics), lipids present some unique advantages and challenges for mass spectrometric analysis. The application of electrospray ionization to crude lipid extracts without prior fractionation—the so-called shotgun approach—is one such example, as it has perhaps been more successfully applied in lipidomics than in any other discipline. Conversely, the diverse molecular structure of lipids means that collision-induced dissociation alone may be limited in providing unique descriptions of complex lipid structures, and the development of additional, complementary tools for ion activation and analysis is required to overcome these challenges. In this article, we discuss the state of the art in lipid mass spectrometry and highlight several areas in which current approaches are deficient and further innovation is required.

  6. Negative thermal ion mass spectrometry of oxygen in phosphates

    NASA Astrophysics Data System (ADS)

    Holmden, C.; Papanastassiou, D. A.; Wasserburg, G. J.

    1997-06-01

    A novel technique for the precise measurement of oxygen isotopes by negative thermal ion mass spectrometry (NTIMS) is presented. The technique is ideally suited to the analysis of oxygen isotopes in phosphates which form intense P03 ion beams. Since P is monoisotopic, the mass spectrum for P0 3- at 79, 80, and 81 corresponds to 1660, 170, and 180. Natural and synthetic phosphates are converted and loaded on the mass spectrometer filament as Ag 3PO 4 precipitated directly from ammoniacal solution. To lower the work function of the filament, BaCl, is added in a 1:1 molar ratio of PO 4:Ba. Using these procedures, Br - mass interference (at 79 and 81 amu) is eliminated for typical analyses. Experiments with 180-enriched water show less than 1 % O-exchange between sample PO 4 and adsorbed water, and there is no O-exchange with trace OZ present in the mass spectrometer source chamber. The ionization efficiency of PO 4, as P0 3- is >10% compared to 0.01% for both conventional dual inlet Gas Isotope Ratio Mass Spectrometry (GIRMS) and secondary ion mass spectrometry (SIMS). Therefore, NTIMS offers exceptional sensitivity enabling routine and precise oxygen isotope analysis of sub-microgram samples of PO 4, (<21 nmoles equivalent CO 2 gas) without need for lengthy chemical pre-treatment reproducibility of the sample. Overall external precision is ±1%c (2σ) for 18O/16 O and 170/15O with of instrumental isotope fractionation (calculated from 18O/16O of ±0.5%c amu -1. Small phosphate samples including single mineral grains from meteorites, or apatite microfossils, can be analyzed by this technique.

  7. Mass spectrometry imaging: Towards a lipid microscope?

    PubMed

    Touboul, David; Brunelle, Alain; Laprévote, Olivier

    2011-01-01

    Biological imaging techniques are the most efficient way to locally measure the variation of different parameters on tissue sections. These analyses are gaining increasing interest since 20 years and allow observing extremely complex biological phenomena at lower and lower time and resolution scale. Nevertheless, most of them only target very few compounds of interest, which are chosen a priori, due to their low resolution power and sensitivity. New chemical imaging technique has to be introduced in order to overcome these limitations, leading to more informative and sensitive analyses for biologists and physicians. Two major mass spectrometry methods can be efficiently used to generate the distribution of biological compounds over a tissue section. Matrix-Assisted Laser Desorption/Ionisation-Mass Spectrometry (MALDI-MS) needs the co-crystallization of the sample with a matrix before to be irradiated by a laser, whereas the analyte is directly desorbed by a primary ion bombardment for Secondary Ion Mass Spectrometry (SIMS) experiments. In both cases, energy used for desorption/ionization is locally deposited -some tens of microns for the laser and some hundreds of nanometers for the ion beam- meaning that small areas over the surface sample can be separately analyzed. Step by step analysis allows spectrum acquisitions over the tissue sections and the data are treated by modern informatics software in order to create ion density maps, i.e., the intensity plot of one specific ion versus the (x,y) position. Main advantages of SIMS and MALDI compared to other chemical imaging techniques lie in the simultaneous acquisition of a large number of biological compounds in mixture with an excellent sensitivity obtained by Time-of-Flight (ToF) mass analyzer. Moreover, data treatment is done a posteriori, due to the fact that no compound is selectively marked, and let us access to the localization of different lipid classes in only one complete acquisition. PMID:20570708

  8. Mass spectrometry-based plasma proteomics: state of the art and future outlook.

    PubMed

    Pernemalm, Maria; Lehtiö, Janne

    2014-08-01

    Mass spectrometry-based plasma proteomics is a field where intense research has been performed during the last decade. Being closely linked to biomarker discovery, the field has received a fair amount of criticism, mostly due to the low number of novel biomarkers reaching the clinic. However, plasma proteomics is under gradual development with improvements on fractionation methods, mass spectrometry instrumentation and analytical approaches. These recent developments have contributed to the revival of plasma proteomics. The goal of this review is to summarize these advances, focusing in particular on fractionation methods, both for targeted and global mass spectrometry-based plasma analysis. PMID:24661227

  9. Uncoiling collagen: a multidimensional mass spectrometry study.

    PubMed

    Simon, H J; van Agthoven, M A; Lam, P Y; Floris, F; Chiron, L; Delsuc, M-A; Rolando, C; Barrow, M P; O'Connor, P B

    2016-01-01

    Mass spectrometry can be used to determine structural information about ions by activating precursors and analysing the resulting series of fragments. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) is a technique that correlates the mass-to-charge (m/z) ratio of fragment and precursor ions in a single spectrum. 2D FT-ICR MS records the fragmentation of all ions in a sample without the need for isolation. To analyse specific precursors, horizontal cross-sections of the spectrum (fragment ion scans) are taken, providing an alternative to conventional tandem mass spectrometry (MS/MS) experiments. In this work, 2D FT-ICR MS has been used to study the tryptic digest of type I collagen, a large protein. Fragment ion scans have been extracted from the 2D FT-ICR MS spectrum for precursor m/z ratios: 951.81, 850.41, 634.34, and 659.34, and 2D FT-ICR MS spectra are compared with a set of 1D MS/MS spectra using different fragmentation methods. The results show that two-dimensional mass spectrometry excells at MS/MS of complex mixtures, simplifying spectra by eliminating contaminant peaks, and aiding the identification of species in the sample. Currently, with desktop computers, 2D FT-ICR MS is limited by data processing power, a limitation which should be alleviated using cluster parallel computing. In order to explore 2D FT-ICR MS for collagen, with reasonable computing time, the resolution in the fragment ion dimension is limited to 256k data points (compared to 4M data points in 1D MS/MS spectra), but the vertical precursor ion dimension has 4096 lines, so the total data set is 1G data points (4 Gbytes). The fragment ion coverage obtained with a blind, unoptimized 2D FT-ICR MS experiment was lower than conventional MS/MS, but MS/MS information is obtained for all ions in the sample regardless of selection and isolation. Finally, although all 2D FT-ICR MS peak assignments were made with the aid of 1D FT-ICR MS data, these results

  10. Computational mass spectrometry for small molecules

    PubMed Central

    2013-01-01

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

  11. Alpha spectrometry applications with mass separated samples.

    PubMed

    Dion, M P; Eiden, Gregory C; Farmer, Orville T; Liezers, Martin; Robinson, John W

    2016-01-01

    (241)Am has been deposited using a novel technique that employs a commercial inductively coupled plasma mass spectrometer. This work presents results of high-resolution alpha spectrometry on the (241)Am samples using a small area passivated implanted planar silicon detector. We have also investigated the mass-based separation capability by developing a (238)Pu sample, present as a minor constituent in a (244)Pu standard, and performed subsequent radiometric counting. With this new sample development method, the (241)Am samples achieved the intrinsic energy resolution of the detector used for these measurements. There was no detectable trace of any other isotopes contained in the (238)Pu implant demonstrating the mass-based separation (or enhancement) attainable with this technique. PMID:26583262

  12. Analysis of Glycosaminoglycans Using Mass Spectrometry

    PubMed Central

    Staples, Gregory O.; Zaia, Joseph

    2015-01-01

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

  13. Desorption electrospray ionisation mass spectrometry and tandem mass spectrometry of low molecular weight synthetic polymers.

    PubMed

    Jackson, Anthony T; Williams, Jonathan P; Scrivens, James H

    2006-01-01

    A range of low molecular weight synthetic polymers has been characterised by means of desorption electrospray ionisation (DESI) combined with both mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Accurate mass experiments were used to aid the structural determination of some of the oligomeric materials. The polymers analysed were poly(ethylene glycol) (PEG), polypropylene glycol (PPG), poly(methyl methacrylate) (PMMA) and poly(alpha-methyl styrene). An application of the technique for characterisation of a polymer used as part of an active ingredient in a pharmaceutical tablet is described. The mass spectra and tandem mass spectra of all of the polymers were obtained in seconds, indicating the sensitivity of the technique. PMID:16912984

  14. Resonance enhanced multiphoton ionization/secondary neutral mass spectrometry and cesium attachment secondary ion mass spectrometry of bronze : a comparison.

    SciTech Connect

    McCann, M. P.; Calaway, W. F.; Pellin, M. J.; Veryovkin, I. V.; Constantinides, I.; Adriaens, A.; Adams, F.; Materials Science Division; Sam Houston State Univ.; Univ. of Antwerp

    2002-05-01

    Archaeologists have considerable interests in ancient bronzes. They want to know how these alloys were produced and how they corroded with time. Modern bronzes, with compositions very close to that of some ancient bronzes, have been produced and two methods were examined to characterize one of these modern bronzes. Analysis of this modern bronze using resonance enhanced multiphoton ionization/secondary neutral mass spectrometry (REMPI/SNMS) is examined in detail and compared to cesium attachment secondary ion mass spectrometry (CsAMS) results. Both REMPI/SNMS and CsAMS were used to quantify the composition of Fe, Ni and Mn in a modern quaternary bronze designed to serve as a certified reference material for an ancient bronze. Both methods exhibit reduced matrix effects when compared to secondary ion mass spectrometry (SIMS) and thus quantification should be simplified. It was found that when relative sensitivity factors obtained from a standard bronze material are used to calibrate the instruments, the REMPI/SNMS measurements yield results that were more sensitive and more accurate.

  15. Membrane composition analysis by imaging mass spectrometry

    SciTech Connect

    Boxer, S G; Kraft, M L; Longo, M; Hutcheon, I D; Weber, P K

    2006-03-29

    Membranes on solid supports offer an ideal format for imaging. Secondary ion mass spectrometry (SIMS) can be used to obtain composition information on membrane-associated components. Using the NanoSIMS50, images of composition variations in membrane domains can be obtained with a lateral resolution better than 100 nm. By suitable calibration, these variations in composition can be translated into a quantitative analysis of the membrane composition. Progress towards imaging small phase-separated lipid domains, membrane-associated proteins and natural biological membranes will be described.

  16. Study of CPP Mechanisms by Mass Spectrometry.

    PubMed

    Sagan, Sandrine; Bechara, Chérine; Burlina, Fabienne

    2015-01-01

    Studying the mechanisms of entry of cell-penetrating peptides (CPPs) requires reliable methods to measure their cellular uptake efficiency, monitor their metabolic stability, and identify their intracellular localization. We describe here a protocol based on the direct detection of peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), which allows the absolute quantification of the intact internalized species and the analysis of their intracellular degradation. This protocol can be easily applied to the simultaneous quantification of different species, for example mixtures of CPPs. PMID:26202265

  17. Mass spectrometry and inhomogeneous ion optics

    NASA Technical Reports Server (NTRS)

    White, F. A.

    1973-01-01

    Work done in several areas to advance the state of the art of magnetic mass spectrometers is described. The calculations and data necessary for the design of inhomogeneous field mass spectrometers, and the calculation of ion trajectories through such fields are presented. The development and testing of solid state ion detection devices providing the capability of counting single ions is discussed. New techniques in the preparation and operation of thermal-ionization ion sources are described. Data obtained on the concentrations of copper in rainfall and uranium in air samples using the improved thermal ionization techniques are presented. The design of a closed system static mass spectrometer for isotopic analyses is discussed. A summary of instrumental aspects of a four-stage mass spectrometer comprising two electrostatic and two 90 deg. magnetic lenses with a 122-cm radius used to study the interaction of ions with solids is presented.

  18. Ultratrace Analysis of Uranium and Plutonium By Mass Spectrometry

    SciTech Connect

    Wacker, John F.; Wogman, Ned A.; Olsen, Khris B.; Petersen, Steven L.; Farmer, O T.; Kelley, James M.; Eiden, Greg C.; Maiti, Tapas C.

    2003-01-01

    At the Pacific Northwest National Laboratory (PNNL), we have developed highly sensitive methods to analyze uranium and plutonium in environmental samples. The development of an ultratrace analysis capability for measuring uranium and plutonium has arisen from a need to detect and characterize environmental samples for signatures associated with nuclear industry processes. Our most sensitive well-developed methodologies employ thermal ionization mass spectrometry (TIMS), however, recent advances in inductively coupled plasma mass spectrometry (ICP-MS) have shown considerable promise for use in detecting uranium and plutonium at ultratrace levels. The work at PNNL has included the development of both chemical separation and purification techniques, as well as the development of mass spectrometric instrumentation and techniques. At the heart of our methodology for TIMS analysis is a procedure that utilizes 100-microliter-volumes of analyte for chemical processing to purify, separate, and load actinide elements into resin beads for subsequent mass spectrometric analysis. The resin bead technique has been combined with a thorough knowledge of the physicochemistry of thermal ion emission to achieve femtogram detection limits for the TIMS analysis of plutonium in environmental samples.

  19. Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

    SciTech Connect

    Ludvigson, L D

    2004-03-05

    I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease prevention and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.

  20. Quantification of diacylglycerol by mass spectrometry.

    PubMed

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

    2013-01-01

    Diacylglycerol (DAG) is an important intermediate of lipid metabolism and a component of phospholipase C signal transduction. Quantification of DAG in plant membranes represents a challenging task because of its low abundance. DAG can be measured by direct infusion mass spectrometry (MS) on a quadrupole time-of-flight mass spectrometer after purification from the crude plant lipid extract via solid-phase extraction on silica columns. Different internal standards are employed to compensate for the dependence of the MS and MS/MS signals on the chain length and the presence of double bonds in the acyl moieties. Thus, using a combination of single MS and MS/MS experiments, quantitative results for the different molecular species of DAGs from Arabidopsis can be obtained. PMID:23681522

  1. [Application of mass spectrometry in mycobacteria].

    PubMed

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

    2016-06-01

    To date, more than 170 species of mycobacteria have been described, of which more than one third may be pathogenic to humans, representing a significant workload for microbiology laboratories. These species must be identified in clinical practice, which has long been a major problem due to the shortcomings of conventional (phenotypic) methods and the limitations and complexity of modern methods largely based on molecular biology techniques. The aim of this review was to briefly describe different aspects related to the use of MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) for the identification of mycobacteria. Several difficulties are encountered with the use of this methodology in these microorganisms mainly due to the high pathogenicity of some mycobacteria and the peculiar structure of their cell wall, requiring inactivation and special protein extraction protocols. We also analysed other relevant aspects such as culture media, the reference methods employed (gold standard) in the final identification of the different species, the cut-off used to accept data as valid, and the databases of the different mass spectrometry systems available. MS has revolutionized diagnosis in modern microbiology; however, specific improvements are needed to consolidate the use of this technology in mycobacteriology. PMID:27389290

  2. Spatial Autocorrelation in Mass Spectrometry Imaging.

    PubMed

    Cassese, Alberto; Ellis, Shane R; Ogrinc Potočnik, Nina; Burgermeister, Elke; Ebert, Matthias; Walch, Axel; van den Maagdenberg, Arn M J M; McDonnell, Liam A; Heeren, Ron M A; Balluff, Benjamin

    2016-06-01

    Mass spectrometry imaging (MSI) is a powerful molecular imaging technique. In microprobe MSI, images are created through a grid-wise interrogation of individual spots by mass spectrometry across a surface. Classical statistical tests for within-sample comparisons fail as close-by measurement spots violate the assumption of independence of these tests, which can lead to an increased false-discovery rate. For spatial data, this effect is referred to as spatial autocorrelation. In this study, we investigated spatial autocorrelation in three different matrix-assisted laser desorption/ionization MSI data sets. These data sets cover different molecular classes (metabolites/drugs, lipids, and proteins) and different spatial resolutions ranging from 20 to 100 μm. Significant spatial autocorrelation was detected in all three data sets and found to increase with decreasing pixel size. To enable statistical testing for differences in mass signal intensities between regions of interest within MSI data sets, we propose the use of Conditional Autoregressive (CAR) models. We show that, by accounting for spatial autocorrelation, discovery rates (i.e., the ratio between the features identified and the total number of features) could be reduced between 21% and 69%. The reliability of this approach was validated by control mass signals based on prior knowledge. In light of the advent of larger MSI data sets based on either an increased spatial resolution or 3D data sets, accounting for effects due to spatial autocorrelation becomes even more indispensable. Here, we propose a generic and easily applicable workflow to enable within-sample statistical comparisons. PMID:27180608

  3. Neutral particle mass spectrometry with nanomechanical systems

    PubMed Central

    Sage, Eric; Brenac, Ariel; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Roukes, Michael L.; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

    2015-01-01

    Current approaches to mass spectrometry (MS) require ionization of the analytes of interest. For high-mass species, the resulting charge state distribution can be complex and difficult to interpret correctly. Here, using a setup comprising both conventional time-of-flight MS (TOF-MS) and nano-electromechanical systems-based MS (NEMS-MS) in situ, we show directly that NEMS-MS analysis is insensitive to charge state: the spectrum consists of a single peak whatever the species’ charge state, making it significantly clearer than existing MS analysis. In subsequent tests, all the charged particles are electrostatically removed from the beam, and unlike TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to measure mass spectra for neutral particles. Thus, it is possible to envisage MS-based studies of analytes that are incompatible with current ionization techniques and the way is now open for the development of cutting-edge system architectures with unique analytical capability. PMID:25753929

  4. Crux: rapid open source protein tandem mass spectrometry analysis.

    PubMed

    McIlwain, Sean; Tamura, Kaipo; Kertesz-Farkas, Attila; Grant, Charles E; Diament, Benjamin; Frewen, Barbara; Howbert, J Jeffry; Hoopmann, Michael R; Käll, Lukas; Eng, Jimmy K; MacCoss, Michael J; Noble, William Stafford

    2014-10-01

    Efficiently and accurately analyzing big protein tandem mass spectrometry data sets requires robust software that incorporates state-of-the-art computational, machine learning, and statistical methods. The Crux mass spectrometry analysis software toolkit ( http://cruxtoolkit.sourceforge.net ) is an open source project that aims to provide users with a cross-platform suite of analysis tools for interpreting protein mass spectrometry data. PMID:25182276

  5. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    SciTech Connect

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-06-16

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

  6. Mass Spectrometry of Protein Complexes: From Origins to Applications

    NASA Astrophysics Data System (ADS)

    Mehmood, Shahid; Allison, Timothy M.; Robinson, Carol V.

    2015-04-01

    Now routine is the ability to investigate soluble and membrane protein complexes in the gas phase of a mass spectrometer while preserving folded structure and ligand-binding properties. Several recent transformative developments have occurred to arrive at this point. These include advances in mass spectrometry instrumentation, particularly with respect to resolution; the ability to study intact membrane protein complexes released from detergent micelles; and the use of protein unfolding in the gas phase to obtain stability parameters. Together, these discoveries are providing unprecedented information on the compositional heterogeneity of biomacromolecules, the unfolding trajectories of multidomain proteins, and the stability imparted by ligand binding to both soluble and membrane-embedded protein complexes. We review these recent breakthroughs, highlighting the challenges that had to be overcome and the physicochemical insight that can now be gained from studying proteins and their assemblies in the gas phase.

  7. Mass spectrometry. [in organic ion and biorganic chemistry and medicine

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Cox, R. E.; Derrick, P. J.

    1974-01-01

    Review of the present status of mass spectrometry in the light of pertinent recent publications spanning the period from December 1971 to January 1974. Following an initial survey of techniques, instruments, and computer applications, a sharp distinction is made between the chemistry of organic (radical-)ions and analytical applications in biorganic chemistry and medicine. The emphasis is on the chemistry of organic (radical-)ions at the expense of inorganic, organometallic, and surface ion chemistry. Biochemistry and medicine are chosen because of their contemporary importance and because of the stupendous contributions of mass spectroscopy to these fields in the past two years. In the review of gas-phase organic ion chemistry, special attention is given to studies making significant contributions to the understanding of ion chemistry.

  8. Perspectives on the future of analytical mass spectrometry

    SciTech Connect

    Basic, C.; Freeman, J.A.; Yost, R.A. )

    1990-11-01

    Unlike the secrecy of the early scientists of Oak Ridge, the free exchange of ideas between scientists at the 43rd Annual Summer Symposium on Analytical Chemistry led to the open discussion of new areas of instrumental development, new interfacing techniques, and increasingly challenging analytical problems. Chief among these challenges is the search for improved methods of analysis of high molecular weight species as questions of biochemical concern enter the realm of analytical MS (mass spectrometry). Furthermore, increasing attention is being focused on the use of chemical reactions in both the gas and solution phases to enhance the analytical capabilities of MS. By highlighting the interests of young mass spectrometrists, the symposium organizers succeeded not only in presenting the future areas of research in analytical MS but in introducing the people who will be pursuing these directives.

  9. Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bathany, Katell; Owens, Neil W.; Guichard, Gilles; Schmitter, Jean-Marie

    2013-03-01

    This study is focused on sequence analysis of peptidomimetic helical oligoureas by means of tandem mass spectrometry, to build a basis for de novo sequencing for future high-throughput combinatorial library screening of oligourea foldamers. After the evaluation of MS/MS spectra obtained for model compounds with either MALDI or ESI sources, we found that the MALDI-TOF-TOF instrument gave more satisfactory results. MS/MS spectra of oligoureas generated by decay of singly charged precursor ions show major ion series corresponding to fragmentation across both CO-NH and N'H-CO urea bonds. Oligourea backbones fragment to produce a pattern of a, x, b, and y type fragment ions. De novo decoding of spectral information is facilitated by the occurrence of low mass reporter ions, representative of constitutive monomers, in an analogous manner to the use of immonium ions for peptide sequencing.

  10. Electrospray and tandem mass spectrometry in biochemistry.

    PubMed Central

    Griffiths, W J; Jonsson, A P; Liu, S; Rai, D K; Wang, Y

    2001-01-01

    Over the last 20 years, biological MS has changed out of all recognition. This is primarily due to the development in the 1980s of 'soft ionization' methods that permit the ionization and vaporization of large, polar, and thermally labile biomolecules. These developments in ionization mode have driven the design and manufacture of smaller and cheaper mass analysers, making the mass spectrometer a routine instrument in the biochemistry laboratory today. In the present review the revolutionary 'soft ionization' methods will be discussed with particular reference to electrospray. The mass analysis of ions will be described, and the concept of tandem MS introduced. Where appropriate, examples of the application of MS in biochemistry will be provided. Although the present review will concentrate on the MS of peptides/proteins and lipids, all classes of biomolecules can be analysed, and much excellent work has been done in the fields of carbohydrate and nucleic acid biochemistry. PMID:11311115

  11. Advanced capabilities for in situ planetary mass spectrometry

    NASA Astrophysics Data System (ADS)

    Arevalo, R. D., Jr.; Mahaffy, P. R.; Brinckerhoff, W. B.; Getty, S.; Benna, M.; van Amerom, F. H. W.; Danell, R.; Pinnick, V. T.; Li, X.; Grubisic, A.; Cornish, T.; Hovmand, L.

    2015-12-01

    NASA GSFC has delivered highly capable quadrupole mass spectrometers (QMS) for missions to Venus (Pioneer Venus), Jupiter (Galileo), Saturn/Titan (Cassini-Huygens), Mars (MSL and MAVEN), and the Moon (LADEE). Our understanding of the Solar System has been expanded significantly by these exceedingly versatile yet low risk and cost efficient instruments. GSFC has developed more recently a suite of advanced instrument technologies promising enhanced science return while selectively leveraging heritage designs. Relying on a traditional precision QMS, the Analysis of Gas Evolved from Samples (AGES) instrument measures organic inventory, determines exposure age and establishes the absolute timing of deposition/petrogenesis of interrogated samples. The Mars Organic Molecule Analyzer (MOMA) aboard the ExoMars 2018 rover employs a two-dimensional ion trap, built analogously to heritage QMS rod assemblies, which can support dual ionization sources, selective ion enrichment and tandem mass spectrometry (MS/MS). The same miniaturized analyzer serves as the core of the Linear Ion Trap Mass Spectrometer (LITMS) instrument, which offers negative ion detection (switchable polarity) and an extended mass range (>2000 Da). Time-of-flight mass spectrometers (TOF-MS) have been interfaced to a range of laser sources to progress high-sensitivity laser ablation and desorption methods for analysis of inorganic and non-volatile organic compounds, respectively. The L2MS (two-step laser mass spectrometer) enables the desorption of neutrals and/or prompt ionization at IR (1.0 up to 3.1 µm, with an option for tunability) or UV wavelengths (commonly 266 or 355 nm). For the selective ionization of specific classes of organics, such as aromatic hydrocarbons, a second UV laser may be employed to decouple the desorption and ionization steps and limit molecular fragmentation. Mass analyzers with substantially higher resolving powers (up to m/Δm > 100,000), such as the Advanced Resolution Organic

  12. Probing Bunyavirus N protein oligomerisation using mass spectrometry

    PubMed Central

    Shepherd, Dale A; Ariza, Antonio; Edwards, Thomas A; Barr, John N; Stonehouse, Nicola J; Ashcroft, Alison E

    2014-01-01

    RATIONALE Bunyaviruses have become a major threat to both humans and livestock in Europe and the Americas. The nucleocapsid (N) protein of these viruses is key to the replication cycle and knowledge of the N oligomerisation state is central to understanding the viral lifecycle and for development of therapeutic strategies. METHODS Bunyamwera virus and Schmallenberg virus N proteins (BUNV-N and SBV-N) were expressed recombinantly in E. coli as hexahistidine-SUMO-tagged fusions, and the tag removed subsequently. Noncovalent nano-electrospray ionisation mass spectrometry was conducted in the presence and absence of short RNA oligonucleotides. Instrumental conditions were optimised for the transmission of intact protein complexes into the gas phase. The resulting protein-protein and protein-RNA complexes were identified and their stoichiometries verified by their mass. Collision-induced dissociation tandem mass spectrometry was used in cases of ambiguity. RESULTS Both BUNV-N and SBV-N proteins reassembled into N-RNA complexes in the presence of RNA; however, SBV-N formed a wider range of complexes with varying oligomeric states. The N:RNA oligomers observed were consistent with a model of assembly via stepwise addition of N proteins. Furthermore, upon mixing the two proteins in the presence of RNA no heteromeric complexes were observed, thus revealing insights into the specificity of oligomerisation. CONCLUSIONS Noncovalent mass spectrometry has provided the first detailed analysis of the co-populated oligomeric species formed by these important viral proteins and revealed insights into their assembly pathways. Using this technique has also enabled comparisons to be made between the two N proteins. PMID:24573811

  13. Inductively Coupled Plasma Zoom-Time-of-Flight Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Dennis, Elise A.; Ray, Steven J.; Enke, Christie G.; Hieftje, Gary M.

    2016-03-01

    A zoom-time-of-flight mass spectrometer has been coupled to an inductively coupled plasma (ICP) ionization source. Zoom-time-of-flight mass spectrometry (zoom-TOFMS) combines two complementary types of velocity-based mass separation. Specifically, zoom-TOFMS alternates between conventional, constant-energy acceleration (CEA) TOFMS and energy-focused, constant-momentum acceleration (CMA) (zoom) TOFMS. The CMA mode provides a mass-resolution enhancement of 1.5-1.7× over CEA-TOFMS in the current, 35-cm ICP-zoom-TOFMS instrument geometry. The maximum resolving power (full-width at half-maximum) for the ICP-zoom-TOFMS instrument is 1200 for CEA-TOFMS and 1900 for CMA-TOFMS. The CMA mode yields detection limits of between 0.02 and 0.8 ppt, depending upon the repetition rate and integration time—compared with single ppt detection limits for CEA-TOFMS. Isotope-ratio precision is shot-noise limited at approximately 0.2% relative-standard deviation (RSD) for both CEA- and CMA-TOFMS at a 10 kHz repetition rate and an integration time of 3-5 min. When the repetition rate is increased to 43.5 kHz for CMA, the shot-noise limited, zoom-mode isotope-ratio precision is improved to 0.09% RSD for the same integration time.

  14. Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.

    ERIC Educational Resources Information Center

    Denoyer, Eric; And Others

    1982-01-01

    Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

  15. New analytical scheme for regular old ordinary mass spectrometry

    SciTech Connect

    Lewis, T.M.; Russell, D.

    1994-12-31

    A unified scheme was developed to define the composition, improve detection and qualitative identification of water soluble organics in heavy oil retort. Elements of the scheme included gas chromatography-mass spectrometry (GC-MS), high resolution mass spectrometry (HRMS), hybrid mass spectrometry-mass spectrometry (EB-TOF) with electron impact (EI) and fast atom bombardment (FAB) ionization and a computerized library search program. As part of the development of the process, each element of the analytical scheme was applied to complex samples of aqueous organic materials extracted from heavy oil retorts. Preliminary investigations have indicated that the heavy oil retort contains hundreds of compounds in ppm/ppb concentrations.

  16. Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products

    NASA Astrophysics Data System (ADS)

    Es-Safi, Nour-Eddine; Essassi, El Mokhtar; Massoui, Mohamed; Banoub, Joseph

    Mass spectrometry is an important tool for the identification and structural elucidation of natural and synthesized compounds. Its high sensitivity and the possibility of coupling liquid chromatography with mass spectrometry detection make it a technique of choice for the investigation of complex mixtures like raw natural extracts. The mass spectrometer is a universal detector that can achieve very high sensitivity and provide information on the molecular mass. More detailed information can be subsequently obtained by resorting to collision-induced dissociation tandem mass spectrometry (CID-MS/MS). In this review, the application of mass spectrometric techniques for the identification of natural and synthetic compounds is presented. The gas-phase fragmentation patterns of a series of four natural flavonoid glycosides, three synthesized benzodiazepines and two synthesized quinoxalinone derivatives were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry techniques. Exact accurate masses were measured using a modorate resolution quadrupole orthogonal time-of-flight QqTOF-MS/MS hybrid mass spectrometer instrument. Confirmation of the molecular masses and the chemical structures of the studied compounds were achieved by exploring the gas-phase breakdown routes of the ionized molecules. This was rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole hexapole-quadrupole (QhQ) tandem mass spectrometer.

  17. Advances in ion trap mass spectrometry: Photodissociation as a tool for structural elucidation

    SciTech Connect

    Stephenson, J.L. Jr.; Booth, M.M.; Eyler, J.R.; Yost, R.A.

    1995-12-01

    Photo-induced dissociation (PID) is the next most frequently used method (after collisional activation) for activation of Polyatomic ions in tandem mass spectrometry. The range of internal energies present after the photon absorption process are much narrower than those obtained with collisional energy transfer. Therefore, the usefulness of PID for the study of ion structures is greatly enhanced. The long storage times and instrumental configuration of the ion trap mass spectrometer are ideally suited for photodissociation experiments. This presentation will focus on both the fundamental and analytical applications of CO{sub 2} lasers in conjunction with ion trap mass spectrometry. The first portion of this talk will examine the fundamental issues of wavelength dependence, chemical kinetics, photoabsorption cross section, and collisional effects on photodissociation efficiency. The second half of this presentation will look at novel instrumentation for electrospray/ion trap mass spectrometry, with the concurrent development of photodissociation as a tool for structural elucidation of organic compounds and antibiotics.

  18. Feature extraction and dimensionality reduction for mass spectrometry data.

    PubMed

    Liu, Yihui

    2009-09-01

    Mass spectrometry is being used to generate protein profiles from human serum, and proteomic data obtained from mass spectrometry have attracted great interest for the detection of early stage cancer. However, high dimensional mass spectrometry data cause considerable challenges. In this paper we propose a feature extraction algorithm based on wavelet analysis for high dimensional mass spectrometry data. A set of wavelet detail coefficients at different scale is used to detect the transient changes of mass spectrometry data. The experiments are performed on 2 datasets. A highly competitive accuracy, compared with the best performance of other kinds of classification models, is achieved. Experimental results show that the wavelet detail coefficients are efficient way to characterize features of high dimensional mass spectra and reduce the dimensionality of high dimensional mass spectra. PMID:19646687

  19. Characterisation of DEFB107 by mass spectrometry

    NASA Astrophysics Data System (ADS)

    McCullough, Bryan J.; Eastwood, Hayden; Clark, Dave J.; Polfer, Nick C.; Campopiano, Dominic J.; Dorin, Julia A.; Maxwell, Alison; Langley, Ross J.; Govan, John R. W.; Bernstein, Summer L.; Bowers, Michael T.; Barran, Perdita E.

    2006-05-01

    Mammalian defensins are small endogenous cationic proteins which form a class of antimicrobial peptides that is part of the innate immune response of all mammalian species [R. Lehrer, Nat. Rev. Microbiol. 2 (9) (2004) 727; T. Ganz, R.I. Lehrer, Curr. Opin. Immunol. 6 (4) (1994) 584] [1] and [2]. We have developed mass spectrometry based strategies for characterising the structure-activity relationship of defensins [D.J. Campopiano, D.J. Clarke, N.C. Polfer, P.E. Barran, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, J. Biol. Chem. 279 (47) (2004) 48671; P.E. Barran, N.C. Polfer, D.J. Campopiano, D.J. Clarke, P.R.R. Langridge-Smith, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, R.P. Millar, M.T. Bowers, Int. J. Mass Spectrom. 240 (2005) 273] [3] and [4], and here we present data obtained from a five cysteine containing [beta]-defensin, DEFB107. The synthetic product of this human defensin exists with a glutathione capping group, its oxidation state and disulphide connectivity have been determined via accurate mass measurements and peptide mass mapping respectively, and despite possessing three disulphide bridges, it does not fit the [beta]-defensin canonical motif. With the use of molecular modelling, we have generated candidate geometries to discern the influence of disulphide bridging on the overall tertiary structure of DEFB107. These are compared with experimental results from ion mobility measurements. Defensins display activity against a wide variety of pathogens including both gram-negative and gram-positive bacteria. Their mechanism of mode of action is unknown, but is believed to involve defensin aggregation at cell surfaces, followed by cell permeabilisation and hence deathE To probe this mechanism, the localisation of DEFB107 in synthetic vesicles was studied using H/D exchange and mass spectrometry. The results obtained are used to analyse the antimicrobial activity of DEFB107.

  20. Mass Spectrometry Methodology in Lipid Analysis

    PubMed Central

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

    2014-01-01

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

  1. Quantitative mass spectrometry of urinary biomarkers

    PubMed Central

    Jerebtsova, Marina; Nekhai, Sergei

    2015-01-01

    The effectiveness of treatment of renal diseases is limited because the lack of diagnostic, prognostic and therapeutic markers. Despite the more than a decade of intensive investigation of urinary biomarkers, no new clinical biomarkers were approved. This is in part because the early expectations toward proteomics in biomarkers discovery were significantly higher than the capability of technology at the time. However, during the last decade, proteomic technology has made dramatic progress in both the hardware and software methods. In this review we are discussing modern quantitative methods of mass-spectrometry and providing several examples of their applications for discovery and validation of renal disease biomarkers. We are optimistic about future prospects for the development of novel of specific clinical urinary biomarkers. PMID:25984422

  2. Recent trends in inorganic mass spectrometry

    SciTech Connect

    Smith, D.H.; Barshick, C.M.; Duckworth, D.C.; Riciputi, L.R.

    1996-10-01

    The field of inorganic mass spectrometry has seen substantial change in the author`s professional lifetime (over 30 years). Techniques in their infancy 30 years ago have matured; some have almost disappeared. New and previously unthought of techniques have come into being; some of these, such as ICP-MS, are reasonably mature now, while others have some distance to go before they can be so considered. Most of these new areas provide fertile fields for researchers, both in the development of new analytical techniques and by allowing fundamental studies to be undertaken that were previously difficult, impossible, or completely unforeseen. As full coverage of the field is manifestly impossible within the framework of this paper, only those areas with which the author has personal contact will be discussed. Most of the work originated in his own laboratory, but that of other laboratories is covered where it seemed appropriate.

  3. In situ secondary ion mass spectrometry analysis

    SciTech Connect

    Groenewold, G.S.; Applehans, A.D.; Ingram, J.C.; Delmore, J.E.; Dahl, D.A.

    1993-01-01

    The direct detection of tributyl phosphate (TBP) on rocks using molecular beam surface analysis [MBSA or in situ secondary ion mass spectrometry (SIMS)] is demonstrated. Quantities as low as 250 ng were detected on basalt and sandstone with little or no sample preparation. Detection of TBP on soil has proven to be more problematic and requires further study. Ethylenediaminetetraacetic acid (EDTA) is more difficult to detect because it is very reactive with surfaces of interest. Nevertheless, it is possible to detect EDTA if the acidity of the surface is controlled. The detection of EDTA-metal complexes is currently an open question, but evidence is presented for the detection of ions arising from a EDTA-lead complex. Carboxylic acids (i.e., citric, ascorbic, malic, succinic, malonic, and oxalic) give characteristic SIM spectra, but their detection on sample surfaces awaits evaluation.

  4. [Application of mass spectrometry in mycology].

    PubMed

    Quiles Melero, Inmaculada; Peláez, Teresa; Rezusta López, Antonio; Garcia-Rodríguez, Julio

    2016-06-01

    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) is becoming an essential tool in most microbiology laboratories. At present, by using a characteristic fungal profile obtained from whole cells or through simple extraction protocols, MALDI-TOF MS allows the identification of pathogenic fungi with a high performance potential. This methodology decreases the laboratory turnaround time, optimizing the detection of mycoses. This article describes the state-of-the-art of the use of MALDI-TOF MS for the detection of human clinical fungal pathogens in the laboratory and discusses the future applications of this technology, which will further improve routine mycological diagnosis. PMID:27389289

  5. China's food safety regulation and mass spectrometry.

    PubMed

    Chu, Xiaogang; Zhang, Feng; Nie, Xuemei; Wang, Wenzhi; Feng, Feng

    2011-01-01

    Food safety is essential to people's health and people's livelihood. To ensure that food safety is an important current strategy of the governments, both regulation and standardization are important support for implementing this strategic initiative effectively. The status and prospects of China's food laws, regulations, and standards system are introduced. China now has established a complete law regime providing a sound foundation and good environment for keeping the health of people, maintaining the order of social economy and promoting the international trade of food. At the same time, it is undoubtedly important to strengthen standardization and improve the food safety standards system. In the administration of food safety, mass spectrometry is becoming more and more important and many analytical methods developed in China are based on its application. PMID:21643903

  6. Electrostatic-spray ionization mass spectrometry.

    PubMed

    Qiao, Liang; Sartor, Romain; Gasilova, Natalia; Lu, Yu; Tobolkina, Elena; Liu, Baohong; Girault, Hubert H

    2012-09-01

    An electrostatic-spray ionization (ESTASI) method has been used for mass spectrometry (MS) analysis of samples deposited in or on an insulating substrate. The ionization is induced by a capacitive coupling between an electrode and the sample. In practice, a metallic electrode is placed close to but not in direct contact with the sample. Upon application of a high voltage pulse to the electrode, an electrostatic charging of the sample occurs leading to a bipolar spray pulse. When the voltage is positive, the bipolar spray pulse consists first of cations and then of anions. This method has been applied to a wide range of geometries to emit ions from samples in a silica capillary, in a disposable pipet tip, in a polymer microchannel, or from samples deposited as droplets on a polymer plate. Fractions from capillary electrophoresis were collected on a polymer plate for ESTASI MS analysis. PMID:22876737

  7. Forensic applications of ambient ionization mass spectrometry.

    PubMed

    Ifa, Demian R; Jackson, Ayanna U; Paglia, Giuseppe; Cooks, R Graham

    2009-08-01

    This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques--to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin--are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents. PMID:19241065

  8. Atmospheric-pressure Penning ionization mass spectrometry.

    PubMed

    Hiraoka, Kenzo; Fujimaki, Susumu; Kambara, Shizuka; Furuya, Hiroko; Okazaki, Shigemitsu

    2004-01-01

    A preliminary study on the atmospheric-pressure Penning ionization (APP(e)I) of gaseous organic compounds with Ar* has been made. The metastable argon atoms (Ar*: 11.55 eV for (3)P(2) and 11.72 eV for (3)P(0)) were generated by the negative-mode corona discharge of atmospheric-pressure argon gas. By applying a high positive voltage (+500 to +1000 V) to the stainless steel capillary for the sample introduction (0.1 mm i.d., 0.3 mm o.d.), strong ion signals could be obtained. The ions formed were sampled through an orifice into the vacuum and mass-analyzed by an orthogonal time-of-flight mass spectrometer. The major ions formed by APP(e)I are found to be molecular-related ions for alkanes, aromatics, and oxygen-containing compounds. Because only the molecules with ionization energies less than the internal energy of Ar* are ionized, the present method will be a selective and highly sensitive interface for gas chromatography/mass spectrometry. PMID:15384154

  9. Visualizing nanoparticle dissolution by imaging mass spectrometry.

    PubMed

    Szakal, Christopher; Ugelow, Melissa S; Gorham, Justin M; Konicek, Andrew R; Holbrook, R David

    2014-04-01

    We demonstrate the ability to visualize nanoparticle dissolution while simultaneously providing chemical signatures that differentiate between citrate-capped silver nanoparticles (AgNPs), AgNPs forced into dissolution via exposure to UV radiation, silver nitrate (AgNO3), and AgNO3/citrate deposited from aqueous solutions and suspensions. We utilize recently developed inkjet printing (IJP) protocols to deposit the different solutions/suspensions as NP aggregates and soluble species, which separate onto surfaces in situ, and collect mass spectral imaging data via time-of-flight secondary ion mass spectrometry (TOF-SIMS). Resulting 2D Ag(+) chemical images provide the ability to distinguish between the different Ag-containing starting materials and, when coupled with mass spectral peak ratios, provide information-rich data sets for quick and reproducible visualization of NP-based aqueous constituents. When compared to other measurements aimed at studying NP dissolution, the IJP-TOF-SIMS approach offers valuable information that can potentially help in understanding the complex equilibria in NP-containing solutions and suspensions, including NP dissolution kinetics and extent of overall dissolution. PMID:24611464

  10. Two-Dimensional Aperture Coding for Magnetic Sector Mass Spectrometry

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code.

  11. Two-dimensional aperture coding for magnetic sector mass spectrometry.

    PubMed

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

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code. PMID:25510933

  12. MASS SPECTROMETRY IMAGING FOR DRUGS AND METABOLITES

    PubMed Central

    Greer, Tyler; Sturm, Robert; Li, Lingjun

    2011-01-01

    Mass spectrometric imaging (MSI) is a powerful analytical technique that provides two- and three-dimensional spatial maps of multiple compounds in a single experiment. This technique has been routinely applied to protein, peptide, and lipid molecules with much less research reporting small molecule distributions, especially pharmaceutical drugs. This review’s main focus is to provide readers with an up-to-date description of the substrates and compounds that have been analyzed for drug and metabolite composition using MSI technology. Additionally, ionization techniques, sample preparation, and instrumentation developments are discussed. PMID:21515430

  13. Laser Mass Spectrometry in Planetary Science

    SciTech Connect

    Wurz, P.; Whitby, J. A.; Managadze, G. G.

    2009-06-16

    Knowing the chemical, elemental, and isotopic composition of planetary objects allows the study of their origin and evolution within the context of our solar system. Exploration plans in planetary research of several space agencies consider landing spacecraft for future missions. Although there have been successful landers in the past, more landers are foreseen for Mars and its moons, Venus, the jovian moons, and asteroids. Furthermore, a mass spectrometer on a landed spacecraft can assist in the sample selection in a sample-return mission and provide mineralogical context, or identify possible toxic soils on Mars for manned Mars exploration. Given the resources available on landed spacecraft mass spectrometers, as well as any other instrument, have to be highly miniaturised.

  14. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    SciTech Connect

    Watrous, Matthew George; Adamic, Mary Louise; Olson, John Eric; Baeck, D. L.; Fox, R. V.; Hahn, P. A.; Jenson, D. D.; Lister, T. E.

    2015-09-01

    The goal of the project, New Paradigms for Isotope Ratio Mass Spectrometry: Raising the Scientific Profile and Improved Performance for Accelerator Mass Spectrometry (AMS) and Thermal Ionization Mass Spectrometry (TIMS), is to ensure that the ongoing isotope ratio determination capability within the U.S. Department of Energy complex is the world’s best for application to nonproliferation. This report spells out the progress of Task 4, Transition of TIMS to AMS for Iodine Analysis, of the larger project. The subtasks under Task 4 and the accomplishments throughout the three year project life cycle are presented in this report. Progress was made in optimization of chemical extraction, determination of a detection limit for 127Iodine, production of standard materials for AMS analysis quality assurance, facilitation of knowledge exchange with respect to analyzing iodine on an AMS, cross comparison with a world-leading AMS laboratory, supercritical fluid extraction of iodine for AMS analysis and electrodeposition of seawater as a direct method of preparation for iodine analysis by AMS--all with the goal of minimizing the time required to stand up an AMS capability for iodine analysis of exposed air filters at INL. An effective extraction method has been developed and demonstrated for iodine analysis of exposed air filters. Innovative techniques to accomplish the cathode preparation for AMS analysis were developed and demonstrated and published. The known gap of a lack of available materials for reference standards in the analysis of iodine by AMS was filled by the preparation of homogenous materials that were calibrated against NIST materials. A minimum limit on the amount of abundant isotope in a sample was determined for AMS analysis. The knowledge exchange occurred with fantastic success. Scientists engaged the international AMS community at conferences, as well as in their laboratories for collaborative work. The supercritical fluid extraction work has positive

  15. Mass Spectrometry of Acoustically Levitated Droplets

    PubMed Central

    Westphall, Michael S.; Jorabchi, Kaveh; Smith, Lloyd M.

    2008-01-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air–droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-μL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing chargere combination after ion desorption. PMID:18582090

  16. Mass spectrometry of acoustically levitated droplets.

    PubMed

    Westphall, Michael S; Jorabchi, Kaveh; Smith, Lloyd M

    2008-08-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air-droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-microL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing charge recombination after ion desorption. PMID:18582090

  17. Single-protein nanomechanical mass spectrometry in real time

    PubMed Central

    Hanay, M.S.; Kelber, S.; Naik, A.K.; Chi, D.; Hentz, S.; Bullard, E.C.; Colinet, E.; Duraffourg, L.; Roukes, M.L.

    2012-01-01

    Nanoelectromechanical systems (NEMS) resonators can detect mass with exceptional sensitivity. Previously, mass spectra from several hundred adsorption events were assembled in NEMS-based mass spectrometry using statistical analysis. Here, we report the first realization of single-molecule NEMS-based mass spectrometry in real time. As each molecule in the sample adsorbs upon the NEMS resonator, its mass and the position-of-adsorption are determined by continuously tracking two driven vibrational modes of the device. We demonstrate the potential of multimode NEMS-based mass spectrometry by analyzing IgM antibody complexes in real-time. NEMS-MS is a unique and promising new form of mass spectrometry: it can resolve neutral species, provides resolving power that increases markedly for very large masses, and allows acquisition of spectra, molecule-by-molecule, in real-time. PMID:22922541

  18. High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

    NASA Astrophysics Data System (ADS)

    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.

  19. Electrospray Ionization Tandem Mass Spectrometry of Ammonium Cationized Polyethers

    NASA Astrophysics Data System (ADS)

    Nasioudis, Andreas; Heeren, Ron M. A.; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F.

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers.

  20. Compressed sensing in imaging mass spectrometry

    NASA Astrophysics Data System (ADS)

    Bartels, Andreas; Dülk, Patrick; Trede, Dennis; Alexandrov, Theodore; Maaß, Peter

    2013-12-01

    Imaging mass spectrometry (IMS) is a technique of analytical chemistry for spatially resolved, label-free and multipurpose analysis of biological samples that is able to detect the spatial distribution of hundreds of molecules in one experiment. The hyperspectral IMS data is typically generated by a mass spectrometer analyzing the surface of the sample. In this paper, we propose a compressed sensing approach to IMS which potentially allows for faster data acquisition by collecting only a part of the pixels in the hyperspectral image and reconstructing the full image from this data. We present an integrative approach to perform both peak-picking spectra and denoising m/z-images simultaneously, whereas the state of the art data analysis methods solve these problems separately. We provide a proof of the robustness of the recovery of both the spectra and individual channels of the hyperspectral image and propose an algorithm to solve our optimization problem which is based on proximal mappings. The paper concludes with the numerical reconstruction results for an IMS dataset of a rat brain coronal section.

  1. Multidimensional mass spectrometry-based shotgun lipidomics.

    PubMed

    Wang, Miao; Han, Xianlin

    2014-01-01

    Multidimensional mass spectrometry-based shotgun lipidomics (MDMS-SL) has become a foundational analytical technology platform among current lipidomics practices due to its high efficiency, sensitivity, and reproducibility, as well as its broad coverage. This platform has been broadly used to determine the altered content and/or composition of lipid classes, subclasses, and individual molecular species induced by diseases, genetic manipulations, drug treatments, and aging, among others. Herein, we briefly discuss the principles underlying this technology and present a protocol for routine analysis of many of the lipid classes and subclasses covered by MDMS-SL directly from lipid extracts of biological samples. In particular, lipid sample preparation from a variety of biological materials, which is one of the key components of MDMS-SL, is described in detail. The protocol for mass spectrometric analysis can readily be expanded for analysis of other lipid classes not mentioned as long as appropriate sample preparation is conducted, and should aid researchers in the field to better understand and manage the technology for analysis of cellular lipidomes. PMID:25270931

  2. Mass spectrometry-based proteomics: existing capabilities and future directions

    SciTech Connect

    Angel, Thomas E.; Aryal, Uma K.; Hengel, Shawna M.; Baker, Erin Shammel; Kelly, Ryan T.; Robinson, Errol W.; Smith, Richard D.

    2012-05-21

    Mass spectrometry-based proteomics provides a means for identification, characterization, and quantification of biomolecules that are integral components of the processes essential for life. Characterization of proteins present in a biological system at the proteome and sub-proteomes (e.g., the phosphoproteome, proteoglycome, or degradome/peptidome) levels provides a foundation for understanding fundamental aspects as well as potentially a range of translational applications. Emerging technologies such as ion mobility separations coupled with mass spectrometry and microchip-based - proteome measurements combined with continued enhancement of MS instrumentation and separation techniques, such as reversed phase liquid chromatography and potentially capillary electrophoresis, show great promise for both broad undirected as well as targeted measurements and will be critical for e.g., the proteome-wide characterization of post translational modifications and identification, or the verification, and validation of potential biomarkers of disease. MS-based proteomics is also increasingly demonstrating great potential for contributing to our understanding of the dynamics, reactions, and roles proteins and peptides play advancing our understanding of biology on a system wide level for a wide range of applications, from investigations of microbial communities, bioremediation, and human health and disease states alike.

  3. US Food and Drug Administration Perspectives on Clinical Mass Spectrometry.

    PubMed

    Lathrop, Julia Tait; Jeffery, Douglas A; Shea, Yvonne R; Scholl, Peter F; Chan, Maria M

    2016-01-01

    Mass spectrometry-based in vitro diagnostic devices that measure proteins and peptides are underutilized in clinical practice, and none has been cleared or approved by the Food and Drug Administration (FDA) for marketing or for use in clinical trials. One way to increase their utilization is through enhanced interactions between the FDA and the clinical mass spectrometry community to improve the validation and regulatory review of these devices. As a reference point from which to develop these interactions, this article surveys the FDA's regulation of mass spectrometry-based devices, explains how the FDA uses guidance documents and standards in the review process, and describes the FDA's previous outreach to stakeholders. Here we also discuss how further communication and collaboration with the clinical mass spectrometry communities can identify opportunities for the FDA to provide help in the development of mass spectrometry-based devices and enhance their entry into the clinic. PMID:26553791

  4. Applications of Mass Spectrometry to Lipids and Membranes

    PubMed Central

    Harkewicz, Richard; Dennis, Edward A.

    2012-01-01

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

  5. Glycosaminoglycan Characterization by Electrospray Ionization Mass Spectrometry Including Fourier Transform Mass Spectrometry

    PubMed Central

    Laremore, Tatiana N.; Leach, Franklin E.; Solakyildirim, Kemal; Amster, I. Jonathan; Linhardt, Robert J.

    2011-01-01

    Electrospray ionization mass spectrometry (ESI MS) is a versatile analytical technique in glycomics of glycosaminoglycans (GAGs). Combined with enzymology, ESI MS is used for assessing changes in disaccharide composition of GAGs biosynthesized under different environmental or physiological conditions. ESI coupled with high-resolution mass analyzers such as a Fourier transform mass spectrometer (FTMS) permits accurate mass measurement of large oligosaccharides and intact GAGs as well as structural characterization of GAG oligosaccharides using information-rich fragmentation methods such as electron detachment dissociation. The first part of this chapter describes methods for disaccharide compositional profiling using ESI MS and the second part is dedicated to FTMS and tandem MS methods of GAG compositional and structural analysis. PMID:20816475

  6. High-Sensitivity Ion Mobility Spectrometry/Mass Spectrometry Using Electrodynamic Ion Funnel Interfaces

    PubMed Central

    Tang, Keqi; Shvartsburg, Alexandre A.; Lee, Hak-No; Prior, David C.; Buschbach, Michael A.; Li, Fumin; Tolmachev, Aleksey; Anderson, Gordon A.; Smith, Richard D.

    2007-01-01

    The utility of ion mobility spectrometry (IMS) for separation of mixtures and structural characterization of ions has been demonstrated extensively, including in the biological and nanoscience contexts. A major attraction of IMS is its speed, several orders of magnitude greater than that of condensed-phase separations. Nonetheless, IMS combined with mass spectrometry (MS) has remained a niche technique, substantially because of limited sensitivity resulting from ion losses at the IMS-MS junction. We have developed a new electrospray ionization (ESI)-IMS-QToF MS instrument that incorporates electrodynamic ion funnels at both front ESI-IMS and rear IMS-QToF interfaces. The front funnel is of the novel “hourglass” design that efficiently accumulates ions and pulses them into the IMS drift tubes. Even for drift tubes of two meter length, ion transmission through IMS and on to QToF is essentially lossless across the range of ion masses relevant to most applications. The RF ion focusing at the IMS terminus does not degrade IMS resolving power, which exceeds 100 (for singly-charged ions) and is close to the theoretical limit. The overall sensitivity of present ESI-IMS-MS system is comparable to that of commercial ESI-MS, which should make IMS-MS suitable for analyses of complex mixtures with ultra-high sensitivity and exceptional throughput. PMID:15889926

  7. High-Sensitivity Ion Mobility Spectrometry/Mass Spectrometry Using Electrodynamic Ion Funnel Interfaces

    SciTech Connect

    Tang, Keqi; Shvartsburg, Alexandre A.; Lee, Hak-No; Prior, David C.; Buschbach, Michael A.; Li, Fumin; Tolmachev, Aleksey V.; Anderson, Gordon A.; Smith, Richard D.

    2005-05-15

    The utility of ion mobility spectrometry (IMS) for separation of mixtures and structural characterization of ions has been demonstrated extensively, including in the biological and nanoscience contexts. A major attraction of IMS is its speed, several orders of magnitude above that of condensed-phase separations. Nonetheless, IMS combined with mass spectrometry (MS) has remained a niche technique, substantially due to limited sensitivity resulting from ion losses at the IMS-MS junction. We have developed a new electrospray ionization (ESI)-IMS-QToF MS instrument that incorporates electrodynamic ion funnels at both front ESI-IMS and back IMS-QToF interfaces. The front funnel is of the novel ''hourglass'' design that efficiently accumulates ions and pulses them into the IMS drift tubes. Even for drift tubes of two meter length, ion transmission through IMS and on to QToF is essentially lossless across the range of ion masses relevant to most applications. The RF ion focusing at IMS terminus does not degrade IMS resolving power, which exceeds 100 (for singly-charged ions) and is close to the theoretical limit. The overall sensitivity of present ESI-IMS-MS system is shown to be comparable to that of commercial ESI-MS, which should make IMS-MS suitable for analyses of complex mixtures with ultra-high sensitivity and exceptional throughput.

  8. Statistical design of mass spectrometry calibration procedures

    SciTech Connect

    Bayne, C.K.

    1996-11-01

    The main objective of this task was to agree on calibration procedures to estimate the system parameters (i.e., dead-time correction, ion-counting conversion efficiency, and detector efficiency factors) for SAL`s new Finnigan MAT-262 mass spectrometer. SAL will use this mass spectrometer in a clean-laboratory which was opened in December 1995 to measure uranium and plutonium isotopes on environmental samples. The Finnigan MAT-262 mass spectrometer has a multi-detector system with seven Faraday cup detectors and one ion- counter for the measurement of very small signals (e.g. 10{sup -17} Ampere range). ORNL has made preliminary estimates of the system parameters based on SAL`s experimental data measured in late 1994 when the Finnigan instrument was relatively new. SAL generated additional data in 1995 to verify the calibration procedures for estimating the dead-time correction factor, the ion-counting conversion factor and the Faraday cup detector efficiency factors. The system parameters estimated on the present data will have to be reestablished when the Finnigan MAT-262 is moved-to the new clean- laboratory. Different methods will be used to analyzed environmental samples than the current measurement methods being used. For example, the environmental samples will be electroplated on a single filament rather than using the current two filament system. An outline of the calibration standard operating procedure (SOP) is included.

  9. Illustrating the Concepts of Isotopes and Mass Spectrometry in Introductory Courses: A MALDI-TOF Mass Spectrometry Laboratory Experiment

    ERIC Educational Resources Information Center

    Dopke, Nancy Carter; Lovett, Timothy Neal

    2007-01-01

    Mass spectrometry is a widely used and versatile tool for scientists in many different fields. Soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI) allow for the analysis of biomolecules, polymers, and clusters. This article describes a MALDI mass spectrometry experiment designed for students in introductory…

  10. Single Cell Proteomics with Ultra-High Sensitivity Mass Spectrometry

    SciTech Connect

    Frank, M

    2005-02-16

    This project was a joint LDRD project between PAT, CMS and NAI with the objective to develop an instrument that analyzes the biochemical composition of single cells in real-time using bioaerosol mass spectrometry (BAMS) combined with advanced laser desorption and ionization techniques. Applications include both biological defense, fundamental cell biology and biomedical research. BAMS analyzes the biochemical composition of single, micrometer-sized particles (such as bacterial cells or spores) that can be directly sampled from air or a suspension. BAMS is based on an earlier development of aerosol time of flight mass spectrometry (ATOFMS) by members of our collaboration [1,2]. Briefly, in ATOFMS and BAMS aerosol particles are sucked directly from the atmosphere into vacuum through a series of small orifices. As the particles approach the ion source region of the mass spectrometer, they cross and scatter light from two CW laser beams separated by a known distance. The timing of the two bursts of scattered light created by each ''tracked'' particle reveals the speed, location and size of the particle. This information then enables the firing of a high-intensity laser such that the resulting laser pulse desorbs and ionizes molecules from the tracked particle just as it reaches the center of the ion source region. The full spectrum of ions is then measured using a time-of-flight mass spectrometer. The ability to rapidly analyze individual particles is clearly applicable to the rapid detection of aerosolized biological warfare agents so long as agent particles can be made to produce mass spectra that are distinct from the spectra of harmless background particles. The pattern of ions formed is determined by the properties of the laser pulse, the particle, and, in aerosol matrix-assisted laser desorption/ionization (MALDI), also the MALDI matrix used. As a result, it is critical that the properties of the laser pulses used for desorption and ionization be carefully chosen

  11. Integration of continuous-flow accelerator mass spectrometry with chromatography and mass-selective detection.

    PubMed

    Flarakos, Jimmy; Liberman, Rosa G; Tannenbaum, Steven R; Skipper, Paul L

    2008-07-01

    Physical combination of an accelerator mass spectrometry (AMS) instrument with a conventional gas chromatograph-mass spectrometer (GC/MS) is described. The resulting hybrid instrument (GC/MS/AMS) was used to monitor mass chromatograms and radiochromatograms simultaneously when (14)C-labeled compounds were injected into the gas chromatograph. Combination of the two instruments was achieved by splitting the column effluent and directing half to the mass spectrometer and half to a flow-through CuO reactor in line with the gas-accepting AMS ion source. The reactor converts compounds in the GC effluent to CO2 as required for function of the ion source. With cholesterol as test compound, the limits of quantitation were 175 pg and 0.00175 dpm injected. The accuracy achieved in analysis of five nonzero calibration standards and three quality control standards, using cholesterol-2,2,3,4,4,6-d6 as injection standard, was 100 +/- 11.8% with selected ion monitoring and 100 +/- 16% for radiochromatography. Respective values for interday precision were 1.0-3.2 and 22-32%. Application of GC/MS/AMS to a current topic of interest was demonstrated in a model metabolomic study in which cultured primary hepatocytes were given [(14)C]glucose and organic acids excreted into the culture medium were analyzed. PMID:18494504

  12. Protein open-access liquid chromatography/mass spectrometry.

    PubMed

    White, Wendy L; Wagner, Craig D; Hall, John T; Chaney, Erin E; George, Bindu; Hofmann, Karen; Miller, Luke A D; Williams, Jon D

    2005-01-01

    Each year increasing numbers of proteins are submitted for routine characterization by liquid chromatography/mass spectrometry (LC/MS). This paper reports a solution that transforms routine LC/MS analysis of proteins into a fully automated process that significantly reduces analyst intervention. The solution developed, protein open-access (OA) LC/MS, consists of web-enabled sample submission and registration, automated data processing, data interpretation, and report generation. Sample submissions and results are recorded in a LIMS that utilizes an Oracle database. The protein sequence is captured during the sample submission process, stored in the database, and utilized to determine the theoretical protein molecular weight. This calculated mass is used to set the parameters for transformation of the mass-to-charge spectra to the mass domain and evaluate the presence or absence of the desired protein. Three protein OA-LC/MS instruments have been deployed in our facility to support protein characterization, purification, and modification efforts. PMID:15609371

  13. Laser desorption lamp ionization source for ion trap mass spectrometry.

    PubMed

    Wu, Qinghao; Zare, Richard N

    2015-01-01

    A two-step laser desorption lamp ionization source coupled to an ion trap mass spectrometer (LDLI-ITMS) has been constructed and characterized. The pulsed infrared (IR) output of an Nd:YAG laser (1064 nm) is directed to a target inside a chamber evacuated to ~15 Pa causing desorption of molecules from the target's surface. The desorbed molecules are ionized by a vacuum ultraviolet (VUV) lamp (filled with xenon, major wavelength at 148 nm). The resulting ions are stored and detected in a three-dimensional quadrupole ion trap modified from a Finnigan Mat LCQ mass spectrometer operated at a pressure of ≥ 0.004 Pa. The limit of detection for desorbed coronene molecules is 1.5 pmol, which is about two orders of magnitude more sensitive than laser desorption laser ionization mass spectrometry using a fluorine excimer laser (157 nm) as the ionization source. The mass spectrum of four standard aromatic compounds (pyrene, coronene, rubrene and 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (OPC)) shows that parent ions dominate. By increasing the infrared laser power, this instrument is capable of detecting inorganic compounds. PMID:25601688

  14. Mass determination of megadalton-DNA Electrospray Ions usingCharge Detection Mass Spectrometry

    SciTech Connect

    Schultz, Jocelyn C.; Hack, Christopher; Benner, Henry W.

    1997-10-01

    Charge detection mass spectrometry (CD-MS) has been used to determine the mass of double-stranded, circular DNA and single-stranded, circular DNA in the range of 2500 to 8000 base pairs (1.5-5.0 MDa). Simultaneous measurement of the charge and velocity of an electrostatically accelerated ion allows a mass determination of the ion, with instrument calibration determined independently of samples. Positive ion mass spectra of electrosprayed commercial DNA samples supplied in tris(hydroxymethyl)ethylenediamine tetraacetic acid buffer, diluted in 50 vol. percent acetonitrile, were obtained without cleanup of the sample. ACD mass spectrum constructed from 3000 ion measurements takes 10 min to acquire and yields the DNA molecular mass directly (mass resolution = 6). The data collected represent progress toward a more automatable alternative to sizing of DNA by gel electrophoresis. In addition to the mass spectra, CD-MS generates charge versus mass plots, which provide another means to investigate the creation and fate of large electrospray ions.

  15. Laser-induced electron capture mass spectrometry

    PubMed

    Wang; Giese

    2000-02-15

    Two techniques are reported for detection of electrophorederivatized compounds by laser-induced electron capture time-of-flight mass spectrometry (LI-EC-TOF-MS). In both cases, a nitrogen laser is used to induce the electron capture. The analyte is deposited in a matrix consisting of a compound with a low ionization potential such as benzo[ghi]perylene in the first technique, where the electron for electron capture apparently comes from this matrix. In the second technique, the analyte is deposited on a silver surface in the absence of matrix. It seems that "monoenergetic" ions instantly desorb from the target surface in the latter case, since the peak width in the continuous extraction mode essentially matches the pulse width of the laser (4 ns). Ten picomoles of 3-O-(pentafluorobenzyl)-alpha-estradiol were detected at a S/N > or = 50, where the spot size of the laser was approximately 0.25% of the sample spot. It is attractive that simple conditions can enable sensitive detection of electrophores on routine TOF-MS equipment. The technique can be anticipated to broaden the range of analytes in both polarity and size that can be detected by EC-MS relative to the range for GC/EC-MS. PMID:10701262

  16. MSSimulator: Simulation of mass spectrometry data.

    PubMed

    Bielow, Chris; Aiche, Stephan; Andreotti, Sandro; Reinert, Knut

    2011-07-01

    Mass spectrometry coupled to liquid chromatography (LC-MS and LC-MS/MS) is commonly used to analyze the protein content of biological samples in large scale studies, enabling quantitation and identification of proteins and peptides using a wide range of experimental protocols, algorithms, and statistical models to analyze the data. Currently it is difficult to compare the plethora of algorithms for these tasks. So far, curated benchmark data exists for peptide identification algorithms but data that represents a ground truth for the evaluation of LC-MS data is limited. Hence there have been attempts to simulate such data in a controlled fashion to evaluate and compare algorithms. We present MSSimulator, a simulation software for LC-MS and LC-MS/MS experiments. Starting from a list of proteins from a FASTA file, the simulation will perform in-silico digestion, retention time prediction, ionization filtering, and raw signal simulation (including MS/MS), while providing many options to change the properties of the resulting data like elution profile shape, resolution and sampling rate. Several protocols for SILAC, iTRAQ or MS(E) are available, in addition to the usual label-free approach, making MSSimulator the most comprehensive simulator for LC-MS and LC-MS/MS data. PMID:21526843

  17. Mass Spectrometry of Nanoparticles is Different

    NASA Astrophysics Data System (ADS)

    Liang, C.-K.; Eller, M. J.; Verkhoturov, S. V.; Schweikert, Emile A.

    2015-08-01

    Secondary ion mass spectrometry, SIMS, is a method of choice for the characterization of nanoparticles, NPs. For NPs with large surface-to-volume ratios, heterogeneity is a concern. Assays should thus be on individual nano-objects rather than an ensemble of NPs; however, this may be difficult or impossible. This limitation can be side-stepped by probing a large number of dispersed NPs one-by-one and recording the emission from each NP separately. A large collection of NPs will likely contain subsets of like-NPs. The experimental approach is to disperse the NPs and hit an individual NP with a single massive cluster (e.g., C-60, Au-400). At impact energies of ~1 keV/atom, they generate notable secondary ion (SI) emission. Examination of small NPs (≤20 nm in diameter) shows that the SI emission is size-dependent and impacts are not all equivalent. Accurate identification of the type of impact is key for qualitative assays of core or outer shell composition. For quantitative assays, the concept of effective impacts is introduced. Selection of co-emitted ejecta combined with rejection (anticoincidence) of substrate ions allows refining chemical information within the projectile interaction volume. Last, to maximize the SI signal, small NPs (≤5 nm in diameter) can be examined in the transmission mode where the SI yields are enhanced ~10-fold over those in the (conventional) reflection direction. Future endeavors should focus on schemes acquiring SIs, electrons, and photons concurrently.

  18. Cytotoxicity Test and Mass Spectrometry of IPMC

    NASA Astrophysics Data System (ADS)

    Takashima, Kazuto; Kamamichi, Norihiro; Yagi, Tohru; Asaka, Kinji; Mukai, Toshiharu

    Ionic polymer-metal composite (IPMC) is a promising material in biomedical actuators and sensors because IPMC is soft and flexible, leading to the safety of the device itself. The purpose of this study is to investigate the biocompatibility of IPMC by in vitro experiments, in order to evaluate the applicability in biomedical fields. In addition to an IPMC specimen prepared by the conventional “impregnation-reduction method” using cationic gold complexes and reducing agents, two specimens were prepared by processes in addition to that used for the conventional IPMC specimen. One specimen was reduced in Na2SO3 solution and another specimen was cleaned in H2O2 solution. Colony-forming test using Chinese hamster V79 cells shows high cytotoxicity of all IPMC specimens. Examination of direct inlet mass spectrometry (DI-MS) revealed that the peak intensity of gold complex (particularly, m/z=180) was different from that of Nafion film. Monitoring the peak at m/z=180 showed a remnant with the structure of phenanthroline in IPMC specimens which were not cleaned in H2O2 solution.

  19. Mass spectrometry of atmospheric pressure plasmas

    NASA Astrophysics Data System (ADS)

    Große-Kreul, S.; Hübner, S.; Schneider, S.; Ellerweg, D.; von Keudell, A.; Matejčík, S.; Benedikt, J.

    2015-08-01

    Atmospheric pressure non-equilibrium plasmas (APPs) are effective source of radicals, metastables and a variety of ions and photons, ranging into the vacuum UV spectral region. A detailed study of these species is important to understand and tune desired effects during the interaction of APPs with solid or liquid materials in industrial or medical applications. In this contribution, the opportunities and challenges of mass spectrometry for detection of neutrals and ions from APPs, fundamental physical phenomena related to the sampling process and their impact on the measured densities of neutrals and fluxes of ions, will be discussed. It is shown that the measurement of stable neutrals and radicals requires a proper experimental design to reduce the beam-to-background ratio, to have little beam distortion during expansion into vacuum and to carefully set the electron energy in the ionizer to avoid radical formation through dissociative ionization. The measured ion composition depends sensitively on the degree of impurities present in the feed gas as well as on the setting of the ion optics used for extraction of ions from the expanding neutral-ion mixture. The determination of the ion energy is presented as a method to show that the analyzed ions are originating from the atmospheric pressure plasma.

  20. Femtosecond laser ablation elemental mass spectrometry.

    PubMed

    Hergenröder, Roland; Samek, Ota; Hommes, Vanja

    2006-01-01

    Laser ablation mass spectrometry (LA-MS) has always been an interesting method for the elemental analysis of solid samples. Chemical analysis with a laser requires small amounts of material. Depending on the analytical detection system, subpicogram quantities may be sufficient. In addition, a focused laser beam permits the spatial characterization of heterogeneity in solid samples typically with micrometer resolution in terms of lateral and depth dimensions. With the advent of high-energy, ultra-short pulse lasers, new possibilities arise. The task of this review is to discuss the principle differences between the ablation process of short (>1 ps) and ultra-short (<1 ps) pulses. Based on the timescales and the energy balance of the process that underlies an ablation event, it will be shown that ultra-short pulses are less thermal and cause less collateral damages than longer pulses. The confinement of the pulse energy to the focal region guarantees a better spatial resolution in all dimensions and improves the analytical figures of merit (e.g., fractionation). Applications that demonstrate these features and that will be presented are in-depth profiling of multi-layer samples and the elemental analysis of biological materials. PMID:16477613

  1. Tandem mass spectrometry: analysis of complex mixtures

    SciTech Connect

    Singleton, K.E.

    1985-01-01

    Applications of tandem mass spectrometry (MS/MS) for the analysis of complex mixtures results in increased specificity and selectivity by using a variety of reagent gases in both negative and positive ion modes. Natural isotopic abundance ratios were examined in both simple and complex mixtures using parent, daughter and neutral loss scans. MS/MS was also used to discover new compounds. Daughter scans were used to identify seven new alkaloids in a cactus species. Three of these alkaloids were novel compounds, and included the first simple, fully aromatic isoquinoline alkaloids reported in Cactaceae. MS/MS was used to characterize the chemical reaction products of coal in studies designed to probe its macromolecular structure. Negative ion chemical ionization was utilized to study reaction products resulting from the oxidation of coal. Possible structural units in the precursor coal were predicted based on the reaction products identified, aliphatic and aromatic acids and their anhydrides. The MS/MS method was also used to characterize reaction products resulting from coal liquefaction and/or extraction. These studies illustrate the types of problems for which MS/MS is useful. Emphasis has been placed on characterization of complex mixtures by selecting experimental parameters which enhance the information obtained. The value of using MS/MS in conjunction with other analytical techniques as well as the chemical pretreatment is demonstrated.

  2. Accelerator Mass Spectrometry in Laboratory Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Nusair, O.; Bauder, W.; Gyürky, G.; Paul, M.; Collon, P.; Fülöp, Zs; Greene, J.; Kinoshita, N.; Palchan, T.; Pardo, R.; Rehm, K. E.; Scott, R.; Vondrasek, R.

    2016-01-01

    The extreme sensitivity and discrimination power of accelerator mass spectrometry (AMS) allows for the search and the detection of rare nuclides either in natural samples or produced in the laboratory. At Argonne National Laboratory, we are developing an AMS setup aimed in particular at the detection of medium and heavy nuclides, relying on the high ion energy achievable with the ATLAS superconducting linear accelerator and on gas-filled magnet isobaric separation. The setup was recently used for the detection of the 146Sm p-process nuclide and for a new determination of the 146Sm half-life (68.7 My). AMS plays an important role in the measurement of stellar nuclear reaction cross sections by the activation method, extending thus the technique to the study of production of long-lived radionuclides. Preliminary measurements of the 147Sm(γ,n)146Sm are described. A measurement of the 142Nd(α,γ)146Sm and 142Nd(α,n)145Sm reactions is in preparation. A new laser-ablation method for the feeding of the Electron Cyclotron Resonance (ECR) ion source is described.

  3. THOR Ion Mass Spectrometer instrument - IMS

    NASA Astrophysics Data System (ADS)

    Retinò, Alessandro; Kucharek, Harald; Saito, Yoshifumi; Fraenz, Markus; Verdeil, Christophe; Leblanc, Frederic; Techer, Jean-Denis; Jeandet, Alexis; Macri, John; Gaidos, John; Granoff, Mark; Yokota, Shoichiro; Fontaine, Dominique; Berthomier, Matthieu; Delcourt, Dominique; Kistler, Lynn; Galvin, Antoniette; Kasahara, Satoshi; Kronberg, Elena

    2016-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. Specifically, THOR will study how turbulent fluctuations at kinetic scales heat and accelerate particles in different turbulent environments within the near-Earth space. To achieve this goal, THOR payload is being designed to measure electromagnetic fields and particle distribution functions with unprecedented resolution and accuracy. Here we present the Ion Mass Spectrometer (IMS) instrument that will measure the full three-dimensional distribution functions of near-Earth main ion species (H+, He+, He++ and O+) at high time resolution (~ 150 ms for H+ , ~ 300 ms for He++) with energy resolution down to ~ 10% in the range 10 eV/q to 30 keV/q and angular resolution ~ 10°. Such high time resolution is achieved by mounting multiple sensors around the spacecraft body, in similar fashion to the MMS/FPI instrument. Each sensor combines a top-hat electrostatic analyzer with deflectors at the entrance together with a time-of-flight section to perform mass selection. IMS electronics includes a fast sweeping high voltage board that is required to make measurements at high cadence. Ion detection includes Micro Channel Plates (MCP) combined with Application-Specific Integrated Circuits (ASICs) for charge amplification, discrimination and time-to-digital conversion (TDC). IMS is being designed to address many of THOR science requirements, in particular ion heating and acceleration by turbulent fluctuations in foreshock, shock and magnetosheath regions. The IMS instrument is being designed and will be built by an international consortium of scientific institutes with main hardware contributions from France, USA, Japan and Germany.

  4. Mass spectrometry of Natural Products: Current, Emerging and Future Technologies

    PubMed Central

    Bouslimani, Amina; Sanchez, Laura M; Garg, Neha; Dorrestein, Pieter C

    2014-01-01

    Although mass spectrometry is a century old technology, we are entering into an exciting time for the analysis of molecular information directly from complex biological systems. In this viewpoint article, we highlight emerging mass spectrometric methods and tools used by the natural product community and give a perspective of future directions where the mass spectrometry field is migrating towards over the next decade. PMID:24801551

  5. The use of mass spectrometry to analyze dried blood spots.

    PubMed

    Wagner, Michel; Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard

    2016-01-01

    Dried blood spots (DBS) typically consist in the deposition of small volumes of capillary blood onto dedicated paper cards. Comparatively to whole blood or plasma samples, their benefits rely in the fact that sample collection is easier and that logistic aspects related to sample storage and shipment can be relatively limited, respectively, without the need of a refrigerator or dry ice. Originally, this approach has been developed in the sixties to support the analysis of phenylalanine for the detection of phenylketonuria in newborns using bacterial inhibition test. In the nineties tandem mass spectrometry was established as the detection technique for phenylalanine and tyrosine. DBS became rapidly recognized for their clinical value: they were widely implemented in pediatric settings with mass spectrometric detection, and were closely associated to the debut of newborn screening (NBS) programs, as a part of public health policies. Since then, sample collection on paper cards has been explored with various analytical techniques in other areas more or less successfully regarding large-scale applications. Moreover, in the last 5 years a regain of interest for DBS was observed and originated from the bioanalytical community to support drug development (e.g., PK studies) or therapeutic drug monitoring mainly. Those recent applications were essentially driven by improved sensitivity of triple quadrupole mass spectrometers. This review presents an overall view of all instrumental and methodological developments for DBS analysis with mass spectrometric detection, with and without separation techniques. A general introduction to DBS will describe their advantages and historical aspects of their emergence. A second section will focus on blood collection, with a strong emphasis on specific parameters that can impact quantitative analysis, including chromatographic effects, hematocrit effects, blood effects, and analyte stability. A third part of the review is dedicated to

  6. Imaging mass spectrometry in biological tissues by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Becker, J S; Becker, J Su; Zoriy, M V; Dobrowolska, J; Matucsh, A

    2007-01-01

    Of all the inorganic mass spectrometric techniques, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) plays a key role as a powerful and sensitive microanalytical technique enabling multi- element trace analysis and isotope ratio measurements at trace and ultratrace level. LA-ICP-MS was used to produce images of detailed regionally-specific element distribution in 20 microm thin sections of different parts of the human brain. The quantitative determination of copper, zinc, lead and uranium distribution in thin slices of human brain samples was performed using matrix-matched laboratory standards via external calibration procedures. Imaging mass spectrometry provides new information on the spatially inhomogeneous element distribution in thin sections of human tissues, for example, of different brain regions (the insular region) or brain tumor tissues. The detection limits obtained for Cu, Zn, Pb and U were in the ng g(-1) range. Possible strategies of LA-ICP-MS in brain research and life sciences include the elemental imaging of thin slices of brain tissue or applications in proteome analysis by combination with matrix-assisted laser desorption/ionization MS to study phospho- and metal- containing proteins will be discussed. PMID:17885277

  7. Aerogel dust collection for in situ mass spectrometry analysis

    NASA Astrophysics Data System (ADS)

    Jones, S. M.; Anderson, M. S.; Davies, A. G.; Kirby, J. P.; Burchell, M. J.; Cole, M. J.

    2015-02-01

    The current technique for conducting in situ mass spectroscopic analysis of dust around extraterrestrial bodies is to have the dust impact a solid plate and analyze the atoms and molecular fragments resulting from the high speed impact. Due to the fact that the kinetic energy from the impact is converted primarily to thermal energy, much of the organic compounds present in the dust may be significantly altered or destroyed. To avoid this problem, aerogel could be used to capture the dust grains, largely intact, maintaining the integrity of the organic compounds in the interior of the dust grains. To demonstrate that organic molecules, present as minor components of silica particles, would survive hypervelocity capture in aerogel and can then be analyzed with mass spectrometry, several light gas gun impact tests and analyses were conducted. Fine particles containing polycyclic aromatic hydrocarbons (PAHs) were captured in aerogel at 5.5 km s-1. The flow of metastable helium from a Direct Analysis Real Time (DART) source was used to desorb and ionize the organics, which were then analyzed with a mass spectrometer. The PAHs were detected and identified by the DART-MS, demonstrating that this method could be used on future flight instruments.

  8. The Need for Speed in Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry

    PubMed Central

    Prentice, Boone M.; Caprioli, Richard M.

    2016-01-01

    Imaging mass spectrometry (IMS) has emerged as a powerful analytical tool enabling the direct molecular mapping of many types of tissue. Specifically, matrix-assisted laser desorption/ ionization (MALDI) represents one of the most broadly applicable IMS technologies. In recent years, advances in solid state laser technology, mass spectrometry instrumentation, computer technology, and experimental methodology have produced IMS systems capable of unprecedented data acquisition speeds (>50 pixels/second). In applications of this technology, throughput is an important consideration when designing an IMS experiment. As IMS becomes more widely adopted, continual improvements in experimental setups will be important to address biologically and clinically relevant time scales.

  9. Electron Transfer Dissociation Mass Spectrometry of Hemoglobin on Clinical Samples

    NASA Astrophysics Data System (ADS)

    Coelho Graça, Didia; Lescuyer, Pierre; Clerici, Lorella; Tsybin, Yury O.; Hartmer, Ralf; Meyer, Markus; Samii, Kaveh; Hochstrasser, Denis F.; Scherl, Alexander

    2012-10-01

    A mass spectrometry-based assay combining the specificity of selected reaction monitoring and the protein ion activation capabilities of electron transfer dissociation was developed and employed for the rapid identification of hemoglobin variants from whole blood without previous proteolytic cleavage. The analysis was performed in a robust ion trap mass spectrometer operating at nominal mass accuracy and resolution. Subtle differences in globin sequences, resulting with mass shifts of about one Da, can be unambiguously identified. These results suggest that mass spectrometry analysis of entire proteins using electron transfer dissociation can be employed on clinical samples in a workflow compatible with diagnostic applications.

  10. Developments in Noble Gas mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hamilton, D.; Schwieters, J. B.; Lloyd, N. S.

    2010-12-01

    D. HAMILTON*, J.B. SCHWIETERS, D. TUTTAS, M. KRUMMEN, M. DEERBERG, N.S. LLOYD1 1Thermo Fisher Scientific, Hanna-Kunath-Str. 11, 28199 Bremen, Germany (*correspondence: Doug.Hamilton@ThermoFisher.com) Recent advances in ion optics and electronic design have added features to the new range of Noble Gas mass spectrometers from Thermo Fisher Scientific that will enable the scientific community to resolve a number of existing analytical limitations. The first development relates to detector technology. Because instrument transmission and ion source efficiency can be very high, detector noise can be the limiting factor for ultra-small sample analysis. Faraday cup detectors are the detectors of choice for high accuracy and high precision isotope ratio measurements because of their unmatched stability and linearity and because of the electronic cross calibration network available to precisely and accurately cross calibrate the multiple Faraday detector channels against each other. Today, most IOMS systems are equipped with current amplifiers using a 1011 Ohm resistor coupled to the feedback loop of a high stability and temperature-stabilized operational amplifier. In this paper we will describe our latest investigations in Faraday cup measurements utilising 1012 & 1013 resistors for signal intensities in the range of 1 pA to 1 fA. The second development relates to a new beam deflection technology added to the ARGUS VI mass spectrometer that enables a fixed collector array to be given some of the properties of a mechanically adjustable array. This enables multidynamic multicollector measurements to be taken utilising a fixed array thus enabling the end user to perform vital detector crosscalibrations “in run”. Lastly we will describe early results on a new high resolution platform and the capabilities of this platform to finally deal with certain isotopic interferences in both the Argon and Neon spectra.

  11. Ambient mass spectrometry imaging: plasma assisted laser desorption ionization mass spectrometry imaging and its applications.

    PubMed

    Feng, Baosheng; Zhang, Jialing; Chang, Cuilan; Li, Liping; Li, Min; Xiong, Xingchuang; Guo, Chengan; Tang, Fei; Bai, Yu; Liu, Huwei

    2014-05-01

    Mass spectrometry imaging (MSI) has been widely used in many research areas for the advantages of providing informative molecular distribution with high specificity. Among the recent progress, ambient MSI has attracted increasing interests owing to its characteristics of ambient, in situ, and nonpretreatment analysis. Here, we are presenting the ambient MSI for traditional Chinese medicines (TCMs) and authentication of work of art and documents using plasma assisted laser desorption ionization mass spectrometry (PALDI-MS). Compared with current ambient MSI methods, an excellent average resolution of 60 μm × 60 μm pixel size was achieved using this system. The feasibility of PALDI-based MSI was confirmed by seal imaging, and its authentication applications were demonstrated by imaging of printed Chinese characters. Imaging of the Radix Scutellariae slice showed that the two active components, baicalein and wogonin, mainly were distributed in the epidermis of the root, which proposed an approach for distinguishing TCMs' origins and the distribution of active components of TCMs and exploring the environmental effects of plant growth. PALDI-MS imaging provides a strong complement for the MSI strategy with the enhanced spatial resolution, which is promising in many research fields, such as artwork identification, TCMs' and botanic research, pharmaceutical applications, etc. PMID:24670045

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  14. Ion Mobility Mass Spectrometry Direct Isotope Abundance Analysis

    SciTech Connect

    Manuel J. Manard, Stephan Weeks, Kevin Kyle

    2010-05-27

    The nuclear forensics community is currently engaged in the analysis of illicit nuclear or radioactive material for the purposes of non-proliferations and attribution. One technique commonly employed for gathering nuclear forensics information is isotope analysis. At present, the state-of-the-art methodology for obtaining isotopic distributions is thermal ionization mass spectrometry (TIMS). Although TIMS is highly accurate at determining isotope distributions, the technique requires an elementally pure sample to perform the measurement. The required radiochemical separations give rise to sample preparation times that can be in excess of one to two weeks. Clearly, the nuclear forensics community is in need of instrumentation and methods that can expedite their decision making process in the event of a radiological release or nuclear detonation. Accordingly, we are developing instrumentation that couples a high resolution IM drift cell to the front end of a MS. The IM cell provides a means of separating ions based upon their collision cross-section and mass-to-charge ratio (m/z). Two analytes with the same m/z, but with different collision cross-sections (shapes) would exit the cell at different times, essentially enabling the cell to function in a similar manner to a gas chromatography (GC) column. Thus, molecular and atomic isobaric interferences can be effectively removed from the ion beam. The mobility selected chemical species could then be introduced to a MS for high-resolution mass analysis to generate isotopic distributions of the target analytes. The outcome would be an IM/MS system capable of accurately measuring isotopic distributions while concurrently eliminating isobaric interferences and laboratory radiochemical sample preparation. The overall objective of this project is developing instrumentation and methods to produce near real-time isotope distributions with a modular mass spectrometric system that performs the required gas-phase chemistry and

  15. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    SciTech Connect

    M. L. Adamic; J. E. Olson; D. D. Jenson; J. G. Eisenmenger; M. G. Watrous

    2012-09-01

    This NA 22 funded research project investigated the transition of iodine isotopic analyses from thermal ionization mass spectrometry (TIMS) to an accelerator mass spectrometry (AMS) system. Previous work (Fiscal Year 2010) had demonstrated comparable data from TIMS and AMS. With AMS providing comparable data with improved background levels and vastly superior sample throughput, improvement in the sample extraction from environmental sample matrices was needed to bring sample preparation throughput closer to the operation level of the instrument. Previous research used an extraction chemistry that was not optimized for yield or refined for reduced labor to prove the principle. This research was done to find an extraction with better yield using less labor per sample to produce a sample ready for the AMS instrument. An extraction method using tetramethyl ammonium hydroxide (TMAH) was developed for removal of iodine species from high volume air filters. The TMAH with gentle heating was superior to the following three extraction methods: ammonium hydroxide aided by sonication, acidic and basic extraction aided by microwave, and ethanol mixed with sodium hydroxide. Taking the iodine from the extraction solvent to being ready for AMS analysis was accomplished by a direct precipitation, as well as, using silver wool to harvest the iodine from the TMAH. Portions of the same filters processed in FY 2010 were processed again with the improved extraction scheme followed by successful analysis by AMS at the Swiss Federal Institute of Technology. The data favorably matched the data obtained in 2010. The time required for analysis has been reduced over the aqueous extraction/AMS approach developed in FY 2010. For a hypothetical batch of 30 samples, the AMS methodology is about 10 times faster than the traditional gas phase chemistry and TIMS analysis. As an additional benefit, background levels for the AMS method are about 1000 times lower than TIMS. This results from the

  16. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  17. The HUPO proteomics standards initiative- mass spectrometry controlled vocabulary

    PubMed Central

    Mayer, Gerhard; Montecchi-Palazzi, Luisa; Ovelleiro, David; Jones, Andrew R.; Binz, Pierre-Alain; Deutsch, Eric W.; Chambers, Matthew; Kallhardt, Marius; Levander, Fredrik; Shofstahl, James; Orchard, Sandra; Antonio Vizcaíno, Juan; Hermjakob, Henning; Stephan, Christian; Meyer, Helmut E.; Eisenacher, Martin

    2013-01-01

    Controlled vocabularies (CVs), i.e. a collection of predefined terms describing a modeling domain, used for the semantic annotation of data, and ontologies are used in structured data formats and databases to avoid inconsistencies in annotation, to have a unique (and preferably short) accession number and to give researchers and computer algorithms the possibility for more expressive semantic annotation of data. The Human Proteome Organization (HUPO)–Proteomics Standards Initiative (PSI) makes extensive use of ontologies/CVs in their data formats. The PSI-Mass Spectrometry (MS) CV contains all the terms used in the PSI MS–related data standards. The CV contains a logical hierarchical structure to ensure ease of maintenance and the development of software that makes use of complex semantics. The CV contains terms required for a complete description of an MS analysis pipeline used in proteomics, including sample labeling, digestion enzymes, instrumentation parts and parameters, software used for identification and quantification of peptides/proteins and the parameters and scores used to determine their significance. Owing to the range of topics covered by the CV, collaborative development across several PSI working groups, including proteomics research groups, instrument manufacturers and software vendors, was necessary. In this article, we describe the overall structure of the CV, the process by which it has been developed and is maintained and the dependencies on other ontologies. Database URL: http://psidev.cvs.sourceforge.net/viewvc/psidev/psi/psi-ms/mzML/controlledVocabulary/psi-ms.obo PMID:23482073

  18. The clinical utility of mass spectrometry based protein assays.

    PubMed

    Lassman, Michael E; McAvoy, Thomas; Chappell, Derek L; Lee, Anita Y; Zhao, Xuemei X; Laterza, Omar F

    2016-08-01

    Reports of mass spectrometry based assays for peptides and proteins have become increasingly common in the literature. The growing interest of mass spectrometry for use in clinical laboratories has been primarily driven by the inherent selectivity of the platform relative to more traditional platforms such as immunoassays. However, the adoption of mass spectrometry for peptide and protein analysis in the clinic has been relatively slow compared its adoption in non-clinical laboratories such as in biomarker discovery efforts or within laboratories that support pharmaceutical and academic research. Here, we review some of the successful reports of MS based assays for human proteins in multiple stages of assay research, and describe how and why the platform was employed in order to demonstrate where and when mass spectrometry based assays will have value in the future. PMID:27259466

  19. Laser mass spectrometry for DNA sequencing, disease diagnosis, and fingerprinting

    NASA Astrophysics Data System (ADS)

    Chen, C. H. Winston; Taranenko, N. I.; Zhu, Y. F.; Chung, C. N.; Allman, S. L.

    1997-05-01

    Since laser mass spectrometry has the potential for achieving very fast DNA analysis, we recently applied it to DNA sequencing, DNA typing for fingerprinting, and DNA screening for disease diagnosis. Two different approaches for sequencing DNA have been successfully demonstrated. One is to sequence DNA with DNA ladders produced from Sanger's enzymatic method. The other is to do direct sequencing without DNA ladders. The need for quick DNA typing for identification purposes is critical for forensic application. Our preliminary results indicate laser mass spectrometry can possible be used for rapid DNA fingerprinting applications at a much lower cost than gel electrophoresis. Population screening for certain genetic disease can be a very efficient step to reducing medical costs through prevention. Since laser mass spectrometry can provide very fast DNA analysis, we applied laser mass spectrometry to disease diagnosis. Clinical samples with both base deletion and point mutation have been tested with complete success.

  20. Quantification of hydroxyacetone and glycolaldehyde using chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Spencer, K. M.; Beaver, M. R.; St. Clair, J. M.; Crounse, J. D.; Paulot, F.; Wennberg, P. O.

    2011-08-01

    Chemical ionization mass spectrometry (CIMS) enables online, fast, in situ detection and quantification of hydroxyacetone and glycolaldehyde. Two different CIMS approaches are demonstrated employing the strengths of single quadrupole mass spectrometry and triple quadrupole (tandem) mass spectrometry. Both methods are capable of the measurement of hydroxyacetone, an analyte with minimal isobaric interferences. Tandem mass spectrometry provides direct separation of the isobaric compounds glycolaldehyde and acetic acid using distinct, collision-induced dissociation daughter ions. Measurement of hydroxyacetone and glycolaldehyde by these methods was demonstrated during the ARCTAS-CARB 2008 campaign and the BEARPEX 2009 campaign. Enhancement ratios of these compounds in ambient biomass burning plumes are reported for the ARCTAS-CARB campaign. BEARPEX observations are compared to simple photochemical box model predictions of biogenic volatile organic compound oxidation at the site.

  1. Recent applications of mass spectrometry in forensic toxicology

    NASA Astrophysics Data System (ADS)

    Foltz, Rodger L.

    1992-09-01

    This review encompasses applications of mass spectrometry reported during the years 1989, 1990 and 1991 for the analysis of cannabinoids, cocaine, opiates, amphetamines, lysergic acid diethylamide (LSD), and their metabolites in physiological specimens.

  2. The use of elemental mass spectrometry in phosphoproteomic applications.

    PubMed

    Maes, Evelyne; Tirez, Kristof; Baggerman, Geert; Valkenborg, Dirk; Schoofs, Liliane; Encinar, Jorge Ruiz; Mertens, Inge

    2016-01-01

    Reversible phosphorylation is one of the most important post-translational modifications in mammalian cells. Because this molecular switch is an important mechanism that diversifies and regulates proteins in cellular processes, knowledge about the extent and quantity of phosphorylation is very important to understand the complex cellular interplay. Although phosphoproteomics strategies are applied worldwide, they mainly include only molecular mass spectrometry (like MALDI or ESI)-based experiments. Although identification and relative quantification of phosphopeptides is straightforward with these techniques, absolute quantification is more complex and usually requires for specific isotopically phosphopeptide standards. However, the use of elemental mass spectrometry, and in particular inductively coupled plasma mass spectrometry (ICP-MS), in phosphoproteomics-based experiments, allow one to absolutely quantify phosphopeptides. Here, these phosphoproteomic applications with ICP-MS as elemental detector are reviewed. Pioneering work and recent developments in the field are both described. Additionally, the advantage of the parallel use of molecular and elemental mass spectrometry is stressed. PMID:25139451

  3. Laser mass spectrometry for DNA sequencing, disease diagnosis, and fingerprinting

    SciTech Connect

    Winston Chen, C.H.; Taranenko, N.I.; Zhu, Y.F.; Chung, C.N.; Allman, S.L.

    1997-03-01

    Since laser mass spectrometry has the potential for achieving very fast DNA analysis, the authors recently applied it to DNA sequencing, DNA typing for fingerprinting, and DNA screening for disease diagnosis. Two different approaches for sequencing DNA have been successfully demonstrated. One is to sequence DNA with DNA ladders produced from Snager`s enzymatic method. The other is to do direct sequencing without DNA ladders. The need for quick DNA typing for identification purposes is critical for forensic application. The preliminary results indicate laser mass spectrometry can possibly be used for rapid DNA fingerprinting applications at a much lower cost than gel electrophoresis. Population screening for certain genetic disease can be a very efficient step to reducing medical costs through prevention. Since laser mass spectrometry can provide very fast DNA analysis, the authors applied laser mass spectrometry to disease diagnosis. Clinical samples with both base deletion and point mutation have been tested with complete success.

  4. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues (2010 Review)

    EPA Science Inventory

    This biennial review covers developments in environmental mass spectrometry for emerging environmental contaminants over the period of 2008-2009. A few significant references that appeared between January and February 2010 are also included. Analytical Chemistry’s current polic...

  5. Mass Spectrometry of Membrane Proteins: A Focus on Aquaporins

    PubMed Central

    Schey, Kevin L.; Grey, Angus C.; Nicklay, Joshua J.

    2015-01-01

    Membrane proteins are abundant, critically important biomolecules that conduct essential functions in all cells and are the targets of a significant number of therapeutic drugs. However, the analysis of their expression, modification, protein–protein interactions, and structure by mass spectrometry has lagged behind similar studies of soluble proteins. Here we review the limitations to analysis of integral membrane and membrane-associated proteins and highlight advances in sample preparation and mass spectrometry methods that have led to the successful analysis of this protein class. Advances in the analysis of membrane protein posttranslational modification, protein–protein interaction, protein structure, and tissue distributions by imaging mass spectrometry are discussed. Furthermore, we focus our discussion on the application of mass spectrometry for the analysis of aquaporins as a prototypical integral membrane protein and how advances in analytical methods have revealed new biological insights into the structure and function of this family of proteins. PMID:23394619

  6. Process for increasing ionic charge in mass spectrometry

    SciTech Connect

    McLuckey, Scott A; He, Min

    2009-06-23

    Processes and apparatus are described for the analysis of molecules or fragments thereof, which are capable of carrying multiple charges, by reacting the multiply charged molecules or fragments thereof with other ions using mass spectrometry.

  7. Photodissociation mass spectrometry: New tools for characterization of biological molecules

    PubMed Central

    Brodbelt, Jennifer S.

    2014-01-01

    Photodissociation mass spectrometry combines the ability to activate and fragment ions using photons with the sensitive detection of the resulting product ions by mass spectrometry. The resulting combination affords a versatile tool for characterization of biological molecules. The scope and breadth of photodissociation mass spectrometry have increased substantially over the past decade as new research groups have entered the field and developed a number of innovative applications that illustrate the ability of photodissociation to produce rich fragmentation patterns, to cleave bonds selectively, and to target specific molecules based on incorporation of chromophores. This review focuses on many of the key developments in photodissociation mass spectrometry over the past decade with a particular emphasis on its applications to biological molecules. PMID:24481009

  8. Molecular Beam Mass Spectrometry (MBMS) (Revised) (Fact Sheet)

    SciTech Connect

    Not Available

    2011-07-01

    This fact sheet provides information about Molecular Beam Mass Spectrometry (MBMS) capabilities and applications at NREL's National Bioenergy Center. NREL has six MBMS systems that researchers and industry partners can use to understand thermochemical biomass conversion and biomass composition recalcitrance.

  9. Desorption electrospray ionization-mass spectrometry of proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the detection of proteins ranging in molecular mass from 12 to 66 kDa. Proteins were uniformly deposited on a solid surface without pretreatment and analyzed with a DESI source coupled to a quadrupole ion trap mass spec...

  10. THE APPLICATION OF MASS SPECTROMETRY TO THE STUDY OF MICROORGANISMS

    EPA Science Inventory

    The purpose of this research project is to use state-of-the-art mass spectrometric techniques, such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS), to provide "protein mass fingerprinting" and protein sequencing i...

  11. Dynamically multiplexed ion mobility time-of-flight mass spectrometry.

    PubMed

    Belov, Mikhail E; Clowers, Brian H; Prior, David C; Danielson, William F; Liyu, Andrei V; Petritis, Brianne O; Smith, Richard D

    2008-08-01

    Ion mobility spectrometry-time-of-flight mass spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity, high-throughput platform, for example, for proteomics applications. In this work, we have developed and integrated three advanced technologies, including efficient ion accumulation in an ion funnel trap prior to IMS separation, multiplexing (MP) of ion packet introduction into the IMS drift tube, and signal detection with an analog-to-digital converter, into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of, for example, blood plasma. To better address variable sample complexity, we have developed and rigorously evaluated a novel dynamic MP approach that ensures correlation of the analyzer performance with an ion source function and provides the improved dynamic range and sensitivity throughout the experiment. The MP IMS-TOFMS instrument has been shown to reliably detect peptides at a concentration of 1 nM in the presence of a highly complex matrix, as well as to provide a 3 orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features were found to yield approximately 700 unique peptide identifications at a false discovery rate (FDR) of approximately 7.5%. Accounting for IMS information gave rise to a projected FDR of approximately 4%. Signal reproducibility was found to be greater than 80%, while the variations in the number of unique peptide identifications were <15%. A single sample analysis was completed in 15 min that constitutes almost 1 order of magnitude improvement compared to a more conventional LC-MS approach. PMID:18582088

  12. Mass spectrometry-based imaging of metabolites and proteins.

    PubMed

    Peukert, Manuela; Becker, Michael; Matros, Andrea; Mock, Hans-Peter

    2014-01-01

    Imaging techniques based on mass spectrometry (MS) have become powerful approaches to decipher the spatial distribution of metabolites and proteins. MS imaging (MSI) mostly relies on matrix-assisted laser desorption/ionization coupled to MS detection, but desorption electrospray ionization is also frequently used. Here we describe our current protocols for MALDI-MSI of seed sections and for root tissue. Detailed procedures for cryo-sectioning, matrix application, image capture, mass spectrometry measurement and data analysis are given. PMID:24136526

  13. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    DOEpatents

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  14. Advances in ion mobility spectrometry–mass spectrometry reveal key insights into amyloid assembly☆

    PubMed Central

    Woods, L.A.; Radford, S.E.; Ashcroft, A.E.

    2013-01-01

    Interfacing ion mobility spectrometry to mass spectrometry (IMS–MS) has enabled mass spectrometric analyses to extend into an extra dimension, providing unrivalled separation and structural characterization of lowly populated species in heterogeneous mixtures. One biological system that has benefitted significantly from such advances is that of amyloid formation. Using IMS–MS, progress has been made into identifying transiently populated monomeric and oligomeric species for a number of different amyloid systems and has led to an enhanced understanding of the mechanism by which small molecules modulate amyloid formation. This review highlights recent advances in this field, which have been accelerated by the commercial availability of IMS–MS instruments. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. PMID:23063533

  15. Determination of polar pesticides in olive oil and olives by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry and high resolution mass spectrometry.

    PubMed

    Nortes-Méndez, Rocío; Robles-Molina, José; López-Blanco, Rafael; Vass, Andrea; Molina-Díaz, Antonio; Garcia-Reyes, Juan F

    2016-09-01

    This article reports the development of two HPLC-MS methods for the determination of polar pesticides in olive oil and olive samples by hydrophilic interaction liquid chromatography (HILIC) separation followed by mass spectrometry detection with tandem mass spectrometry using a triple quadrupole instrument operated in multiple reaction monitoring mode (HILIC-MS/MS) or electrospray time-of-flight mass spectrometry (HILIC-TOFMS). The selected polar pesticides included in the study were: amitrol, cyromazine, diquat, paraquat, mepiquat, trimethylsulfonium (trimesium, glyphosate counterion) and fosetyl aluminium. The simple sample treatment procedure was based on liquid partitioning with methanol. The performance of the sample extraction was evaluated in terms of recovery rates and matrix effects in both olive oil and olives matrices. The results obtained for olive oil were satisfactory while, due to the high complexity of olives, poor recovery rates were obtained for the extraction of diquat, paraquat and amitrol, although with a reasonable precision enabling its use in routine analysis. Similarly, matrix effects were minor in the case of olive oil (ca. 20% suppression average), while significantly higher suppression was observed for olives (30-50% suppression average). The studied approaches were found to be useful for the determination of the pesticides studied in olive oil and olives with limits of quantitation below 5µgkg(-1) in most cases when tandem mass spectrometry was used, thus being in compliance with MRLs set by current EU regulation. PMID:27343599

  16. Biomark/Organic Analysis with Time-of-Flight Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Waite, J. Hunter, Jr.

    2004-01-01

    The concept of a Comprehensive 2-Dimensional Gas Chromatography coupled with Time-of-Flight Mass Spectrometry (GCxGC-TOWS) for the analysis of organic compounds has been proven with commercially available instrumentation (LECO Corp). The performance of a GCxGC instrument has been characterized in various stages using two independent breadboard systems. The GCxGC separation systems, including the thermal modulator, have been miniaturized to the size of a benchtop configuration. One breadboard system employs a Flame Ionization Detector (FID), whereas the second breadboard system employs a Time-of-Fight mass spectrometer (TOFWS) as a detection system.

  17. Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams

    SciTech Connect

    Debord, J. Daniel; Smith, Donald F.; Anderton, Christopher R.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana; Gomer, Richard H.; Fernandez-Lima, Francisco A.

    2014-06-09

    High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.

  18. The Chromatographic Role in High Resolution Mass Spectrometry for Non-Targeted Analysis

    NASA Astrophysics Data System (ADS)

    Croley, Timothy R.; White, Kevin D.; Callahan, John H.; Musser, Steven M.

    2012-09-01

    Resolution improvements in time-of-flight instrumentation and the emergence of the Orbitrap mass spectrometer have researchers using high resolution mass spectrometry to determine elemental compositions and performing screening methods based on the full-scan data from these instruments. This work is focused on examining instrument performance of both a QTOF and a bench-top Orbitrap. In this study, the impact of chromatographic resolution on mass measurement accuracy, mass measurement precision, and ion suppression is examined at a fundamental level. This work was extended to a mixture of over 200 pesticides to determine how well two different software algorithms componentized and correctly identified these compounds under different sets of chromatographic conditions, where co-elution was expected to vary markedly.

  19. Schottky Mass Spectrometry on 152Sm Projectile Fragments*

    NASA Astrophysics Data System (ADS)

    Yan, X. L.; Litvinov, Yu. A.; Bosch, F.; Brandau, C.; Chen, L.; Geissel, H.; Knöbel, R.; Kozhuharov, C.; Kurcewicz, J.; Litvinov, S. A.; Münzenberg, G.; Nociforo, C.; Nolden, F.; Plass, W. R.; Sanjari, M. S.; Scheidenberger, C.; Steck, M.; Sun, B.; Tu, X. L.; Wang, M.; Weick, H.; Winckler, N.; Winkler, M.; Xu, H. S.; Zhang, Y. H.; Zhou, X. H.

    Direct mass measurements of neutron-deficient 152Sm projectile fragments were conducted at the FRS-ESR facility at GSI by employing the time-resolved Schottky Mass Spectrometry. 311 different nuclides were identified by means of their revolution frequencies. Charge-dependent systematic differences between the fitted mass values and the literature mass values are observed in the data analysis. The origin of this systematic deviation is still under discussion. The latest progress on the data analysis is presented.

  20. DETERMINATION OF ELEMENTAL COMPOSITIONS BY HIGH RESOLUTION MASS SPECTROMETRY WITHOUT MASS CALIBRANTS

    EPA Science Inventory

    Widely applicable mass calibrants, including perfluorokerosene, are available for gas-phase introduction of analytes ionized by electron impact (EI) prior to analysis using high resolution mass spectrometry. Unfortunately, no all-purpose calibrants are available for recently dev...

  1. Incorporating Biological Mass Spectrometry into Undergraduate Teaching Labs, Part 2: Peptide Identification via Molecular Mass Determination

    ERIC Educational Resources Information Center

    Arnquist, Isaac J.; Beussman, Douglas J.

    2009-01-01

    Mass spectrometry has become a routine analytical tool in the undergraduate curriculum in the form of GC-MS. While relatively few undergraduate programs have incorporated biological mass spectrometry into their programs, the importance of these techniques, as demonstrated by their recognition with the 2002 Nobel Prize, will hopefully lead to…

  2. NEGATIVE-ION MASS SPECTROMETRY OF SULFONYLUREA HERBICIDES

    EPA Science Inventory

    Sulfonylurea herbicides have been studied using neg-ion desorption chem.-ionization (DCI) mass spectrometry (MS) and DCI-MS/MS techniques. Both {M-H]- and M.- ions were obsd. in the DCI mass spectra. The collisonally activated dissocn. (CAD) spectra were characteristic of the str...

  3. Desorption electrospray ionization mass spectrometry of intact bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate 7 bacterial species based on their measured DESI-mass spectral profile. Both Gram positive and Gram negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordete...

  4. Analysis of intact bacteria using rapid evaporative ionisation mass spectrometry.

    PubMed

    Strittmatter, Nicole; Jones, Emrys A; Veselkov, Kirill A; Rebec, Monica; Bundy, Jacob G; Takats, Zoltan

    2013-07-14

    An identification system for microorganisms based on recently developed rapid evaporative ionisation mass spectrometry (REIMS) is presented. Nine bacterial species cultured on various growth media were correctly identified to family-, genus-, and species-level based on their different mass spectral fingerprints using a cross-validated maximum margin criterion model. PMID:23736664

  5. Mass spectrometry in the U.S. space program: past, present, and future

    NASA Technical Reports Server (NTRS)

    Palmer, P. T.; Limero, T. F.

    2001-01-01

    Recent years have witnessed significant progress on the miniaturization of mass spectrometers for a variety of field applications. This article describes the development and application of mass spectrometry (MS) instrumentation to support of goals of the U.S. space program. Its main focus is on the two most common space-related applications of MS: studying the composition of planetary atmospheres and monitoring air quality on manned space missions. Both sets of applications present special requirements in terms of analytical performance (sensitivity, selectivity, speed, etc.), logistical considerations (space, weight, and power requirements), and deployment in perhaps the harshest of all possible environments (space). The MS instruments deployed on the Pioneer Venus and Mars Viking Lander missions are reviewed for the purposes of illustrating the unique features of the sample introduction systems, mass analyzers, and vacuum systems, and for presenting their specifications which are impressive even by today's standards. The various approaches for monitoring volatile organic compounds (VOCs) in cabin atmospheres are also reviewed. In the past, ground-based GC/MS instruments have been used to identify and quantify VOCs in archival samples collected during the Mercury, Apollo, Skylab, Space Shuttle, and Mir missions. Some of the data from the more recent missions are provided to illustrate the composition data obtained and to underscore the need for instrumentation to perform such monitoring in situ. Lastly, the development of two emerging technologies, Direct Sampling Ion Trap Mass Spectrometry (DSITMS) and GC/Ion Mobility Spectrometry (GC/IMS), will be discussed to illustrate their potential utility for future missions. c 2001 American Society for Mass Spectrometry.

  6. Mass Spectrometry-Based Tissue Imaging of Small Molecules

    PubMed Central

    Ferguson, Carly N.; Fowler, Joseph W.M.; Waxer, Jonathan F.; Gatti, Richard A.; Loo, Joseph A.

    2014-01-01

    Mass spectrometry imaging (MSI) of tissue samples is a promising analytical tool that has quickly become associated with biomedical and pharmacokinetic studies. It eliminates several labor-intensive protocols associated with more classical imaging techniques, and provides accurate, histological data at a rapid pace. Because mass spectrometry is used as the readout, MSI can be applied to almost any molecule, especially those that are biologically relevant. Many examples of its utility in the study of peptides and proteins have been reported; here we discuss its value in the mass range of small molecules. We explore its success and potential in the analysis of lipids, medicinals, and metal-based compounds by featuring representative studies from mass spectrometry imaging laboratories around the globe. PMID:24952187

  7. Use of mass spectrometry for imaging metabolites in plants

    SciTech Connect

    Lee, Young-Jin; Perdian, David; Song, Zhihong; Yeung, Edward; Nikolau, Basil

    2012-03-27

    We discuss and illustrate recent advances that have been made to image the distribution of metabolites among cells and tissues of plants using different mass spectrometry technologies. These technologies include matrix-assisted laser desorption ionization, desorption electrospray ionization, and secondary ion mass spectrometry. These are relatively new technological applications of mass spectrometry and they are providing highly spatially resolved data concerning the cellular distribution of metabolites. We discuss the advantages and limitations of each of these mass spectrometric methods, and provide a description of the technical barriers that are currently limiting the technology to the level of single-cell resolution. However, we anticipate that advances in the next few years will increase the resolving power of the technology to provide unprecedented data on the distribution of metabolites at the subcellular level, which will increase our ability to decipher new knowledge concerning the spatial organization of metabolic processes in plants.

  8. Use of Mass spectrometry for imaging metabolites in plants

    SciTech Connect

    Lee, Young Jin; Perdian, David C.; Song, Zhihong; Yeung, Edward S.; Nikolau, Basil

    2012-03-27

    We discuss and illustrate recent advances that have been made to image the distribution of metabolites among cells and tissues of plants using different mass spectrometry technologies. These technologies include matrix-assisted laser desorption ionization, desorption electrospray ionization, and secondary ion mass spectrometry. These are relatively new technological applications of mass spectrometry and they are providing highly spatially resolved data concerning the cellular distribution of metabolites. We discuss the advantages and limitations of each of these mass spectrometric methods, and provide a description of the technical barriers that are currently limiting the technology to the level of single-cell resolution. However, we anticipate that advances in the next few years will increase the resolving power of the technology to provide unprecedented data on the distribution of metabolites at the subcellular level, which will increase our ability to decipher new knowledge concerning the spatial organization of metabolic processes in plants.

  9. Structural Characterization of Methylenedianiline Regioisomers by Ion Mobility-Mass Spectrometry, Tandem Mass Spectrometry, and Computational Strategies: I. Electrospray Spectra of 2-Ring Isomers

    PubMed Central

    2015-01-01

    Purified methylenedianiline (MDA) regioisomers were structurally characterized and differentiated using tandem mass spectrometry (MS/MS), ion mobility-mass spectrometry (IM-MS), and IM-MS/MS in conjunction with computational methods. It was determined that protonation sites on the isomers can vary depending on the position of amino groups, and the resulting protonation sites play a role in the gas-phase stability of the isomer. We also observed differences in the relative distributions of protonated conformations depending on experimental conditions and instrumentation, which is consistent with previous studies on aniline in the gas phase. This work demonstrates the utility of a multifaceted approach for the study of isobaric species and elucidates why previous MDA studies may have been unable to detect and/or differentiate certain isomers. Such analysis may prove useful in the characterization of larger MDA multimeric species, industrial MDA mixtures, and methylene diphenyl diisocyanate (MDI) mixtures used in polyurethane synthesis. PMID:24678803

  10. Understanding ligand effects in gold clusters using mass spectrometry.

    PubMed

    Johnson, Grant E; Laskin, Julia

    2016-06-21

    -built instrument combined with in situ time of flight secondary ion mass spectrometry (TOF-SIMS). Jointly, this multipronged experimental approach allows characterization of the full spectrum of relevant phenomena including cluster synthesis, ligand exchange, thermochemistry, surface immobilization, and reactivity. The fundamental insights obtained from this work will facilitate the directed synthesis of gold clusters with predetermined size and properties for specific applications. PMID:27221357

  11. Atmospheric sampling glow discharge ionizataion and triple quadrupole tandem mass spectrometry for explosives vapor detection

    SciTech Connect

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.; Hart, K.J.; Glish, G.L.; Grant, B.C.; Chambers, D.M.

    1993-08-01

    The detection and identification of trace vapors of hidden high explosives is an excellent example of a targeted analysis problem. It is desirable to push to ever lower levels the quantity or concentration of explosives material that provides an analytical signal, while at the same time discriminating against all other uninteresting material. The detection system must therefore combine high sensitivity with high specificity. This report describes the philosophy behind the use of atmospheric sampling glow discharge ionization, which is a sensitive, rugged, and convenient means for forming anions from explosives molecules, with tandem mass spectrometry, which provides unparalleled specificity in the identification of explosives-related ions. Forms of tandem mass spectrometry are compared and contrasted to provide a summary of the characteristics to be expected from an explosives detector employing mass spectrometry/mass spectrometry. The instrument developed for the FAA, an atmospheric sampling glow discharge/triple quadrupole mass spectrometer, is described in detail with particular emphasis on the ion source/spectrometer interface and on the capabilities of the spectrometer. Performance characteristics of the system are also described as they pertain to explosives of interest including a description of an automated procedure for the detection and identification of specific explosives. A comparison of various tandem mass spectrometers mated with atmospheric sampling glow discharge is then described and preliminary studies with a vapor preconcentration system provided by the FAA will be described.

  12. Analysis of environmental samples for explosives and explosives degradation products by liquid chromatography-mass spectrometry

    SciTech Connect

    Gates, P.M.; Furlong, E.T.; Lindley, C.E.; Burkhardt, M.R.

    1994-12-31

    Nitroaromatic explosives and their degradation products are regulated water-soluble contaminants that may pose a hazard to human health and could be important water contaminants. The reliable identification of most explosives, in particular, the identification of degradation products, is a major shortcoming in most analytical methods. As an improvement, high-performance liquid chromatography (HPLC) (coupled to Thermospray) mass spectrometry was used to determine compound molecular weights, and tandem-mass spectrometry was applied to confirm molecular structure. Compounds were separated isocratically using methanol-water with an octadecylsilane HPLC column. The identities of known nitroaromatic explosives were confirmed by combined ultraviolet absorbance and negative ion mass spectra. For optimal detection of known compounds, selected ion monitoring mass spectrometry was used. Calibration curves fit quadratic models, with correlation coefficients typically exceeding 0.995 over two orders of magnitude. Instrument detection limits ranged from 2.5 to 10 nanograms per injection, resulting in method-detection limits from about 100 to 400 nanograms per liter for a typical water sample. Unknown analytes (indicated by optical spectra) were identified by full scan and tandem mass spectrometry experiments on sample extracts or isolated extract fractions. This combined ultraviolet-diode array mass spectrometric approach is a superior method for analyzing soil or water samples where known explosives and unknown degradation products might be present.

  13. Chemical recoveries of technetium-99 for various procedures using inductively coupled plasma-mass spectrometry

    SciTech Connect

    Ihsanullah; East, B.W.

    1993-12-31

    The procedure for the determination of {sup 99}Tc inductively coupled plasma-mass spectrometry (ICP-MS) was based on the modification of a variety of available separation techniques. Standard Ru and Rh solutions were used for checking decontaminations and instrument response respectively. Technetium-99 and {sup 95m}Tc tracers were applied as yield monitors using ICP-MS and gamma-ray spectrometry respectively. Percent recoveries are reported for a variety of radiochemical separation procedures for water (58-83%), seaweed (10-76%), and for soil matrices (19-79%).

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Combining Capillary Electrophoresis with Mass Spectrometry for Applications in Proteomics

    SciTech Connect

    Simpson, David C.; Smith, Richard D.

    2005-04-01

    Throughout the field of global proteomics, ranging from simple organism studies to human medical applications, the high sample complexity creates demands for improved separations and analysis techniques. Furthermore, with increased organism complexity, the correlation between proteome and genome becomes less certain due to extensive mRNA processing prior to translation. In this way, the same DNA sequence can potentially code for regions in a number of distinct proteins; quantitative differences in expression (or abundance) between these often-related species are of significant interest. Well-established proteomics techniques, which use genomic information to identify peptides that originate from protease digestion, often cannot easily distinguish between such gene products; intact protein-level analyses are required to complete the picture, particularly for identifying post-translational modifications. While chromatographic techniques are currently better suited to peptide analysis, capillary electrophoresis (CE) in combination with mass spectrometry (MS) may become important for intact protein analysis. This review focuses on CE/MS instrumentation and techniques showing promise for such applications, highlighting those with greatest potential. Reference will also be made to developments relevant to peptide-level analyses for use in time- or sample-limited situations.

  16. Present and future prospects of accelerator mass spectrometry

    SciTech Connect

    Kutschera, W.

    1987-04-01

    Accelerator Mass Spectrometry (AMS) has become a powerful technique for measuring extremely low abundances (10/sup -10/ to 10/sup -15/ relative to stable isotopes) of long-lived radioisotopes with half-lives in the range from 10/sup 2/ to 10/sup 8/ years. With a few exceptions, tandem accelerators turned out to be the most useful instruments for AMS measurements. Both natural (mostly cosmogenic) and man-made (anthropogenic) radioisotopes are studied with this technique. In some cases very low concentrations of stable isotope are also measured. Applications of AMS cover a large variety of fields including anthropology, archaeology, oceanography, hydrology, climatology, volcanology, minerals exploration, cosmochemistry, meteoritics, glaciology, sedimentary processes, geochronology, environmental physics, astrophysics, nuclear and particle physics. Present and future prospects of AMS are discussed as an interplay between the continuous development of new techniques and the investigation of problems in the above mentioned fields. Typical factors to be considered are energy range and type of accelerator, and the possibilities of dedicated versus partial use of new or existing accelerators.

  17. Determination of hair nicotine by gas chromatography-mass spectrometry.

    PubMed

    Man, Che Nin; Ismail, Syazwani; Harn, Gam Lay; Lajis, Razak; Awang, Rahmat

    2009-01-15

    Hair nicotine is a known biomarker for monitoring long-term environmental tobacco smoke (ETS) exposure and smoking status. In general, hair nicotine assay involves alkaline digestion, extraction and instrumental analysis. The gas chromatography-mass spectrometry (GC-MS) assay currently developed has shown to be of high throughput with average approximately 100 hair samples being extracted and analyzed per day. This was achieved through simplified extraction procedure and shortened GC analysis time. The extraction was improved by using small volume (0.4 mL) of organic solvent that does not require further evaporation and salting steps prior to GC-MS analysis. Furthermore, the amount of hair utilized in the extraction was very little (5 mg) while the sensitivity and selectivity of the assay is equal, if not better than other established methods. The linearity of the assay (r(2)>0.995), limit of quantitation (0.04 ng/mg hair), within- and between-assays accuracies and precisions (<11.4%) and mean recovery (92.6%) were within the acceptable range. PMID:19109080

  18. A pyrolysis-mass spectrometry study of Corynebacterium spp.

    PubMed

    Hindmarch, J M; Magee, J T; Hadfield, M A; Duerden, B I

    1990-02-01

    Clinical (66) and collection (38) strains of Corynebacterium spp., including C. jeikeium and CDC group D2, and of Listeria monocytogenes were examined. Conventional characters used in species identification were assessed by a microbiochemical method, and pyrolysis-mass spectrometry (Py-MS) was performed with a Horizon Instruments PYMS 200X. Classification based on Py-MS data yielded clusters that corresponded with species identification and classification groups from conventional data. One small group of clinical strains, homogeneous in conventional tests and Py-MS, comprised isolates from sputum samples from patients undergoing ventilation; they were similar to collection strains of C. renale and C. striatum; the latter species has been implicated in chest infection. Another group, similar to C. minutissimum in both systems, comprised clinical strains isolated from urogenital specimens. L. monocytogenes strains were clearly distinct from Corynebacterium spp. Groups comprising CDC D2 strains and C. jeikeium were resolved, and were similar to other Corynebacterium spp. Two collection strains of C. xerosis were distinct in conventional tests and Py-MS. PMID:2106034

  19. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics.

    PubMed

    Garcia, Antonia; Barbas, Coral

    2011-01-01

    Metabolic fingerprinting, the main tool in metabolomics, is a non-targeted methodology where all detectable peaks (or signals), including those from unknown analytes, are considered to establish sample classification. After pattern comparison, those signals changing in response to a specific situation under investigation are identified to gain biological insight. For this purpose, gas chromatographymass spectrometry (GC-MS) has a drawback in that only volatile compounds or compounds that can be made volatile after derivatization can be analysed, and derivatization often requires extensive sample treatment. However, once the analysis is focused on low molecular weight metabolites, GC-MS is highly efficient, sensitive, and reproducible. Moreover, it is quantitative, and its compound identification capabilities are superior to other separation techniques because GC-MS instruments obtain mass spectra with reproducible fragmentation patterns, which allow for the creation of public databases. This chapter describes well-established protocols for metabolic fingerprinting (i.e. the comprehensive analysis of small molecules) in plasma and urine using GC-MS. Guidelines will also be provided regarding subsequent data pre-treatment, pattern recognition, and marker identification. PMID:21207291

  20. Large Scale Chemical Cross-linking Mass Spectrometry Perspectives

    PubMed Central

    Zybailov, Boris L.; Glazko, Galina V.; Jaiswal, Mihir; Raney, Kevin D.

    2014-01-01

    The spectacular heterogeneity of a complex protein mixture from biological samples becomes even more difficult to tackle when one’s attention is shifted towards different protein complex topologies, transient interactions, or localization of PPIs. Meticulous protein-by-protein affinity pull-downs and yeast-two-hybrid screens are the two approaches currently used to decipher proteome-wide interaction networks. Another method is to employ chemical cross-linking, which gives not only identities of interactors, but could also provide information on the sites of interactions and interaction interfaces. Despite significant advances in mass spectrometry instrumentation over the last decade, mapping Protein-Protein Interactions (PPIs) using chemical cross-linking remains time consuming and requires substantial expertise, even in the simplest of systems. While robust methodologies and software exist for the analysis of binary PPIs and also for the single protein structure refinement using cross-linking-derived constraints, undertaking a proteome-wide cross-linking study is highly complex. Difficulties include i) identifying cross-linkers of the right length and selectivity that could capture interactions of interest; ii) enrichment of the cross-linked species; iii) identification and validation of the cross-linked peptides and cross-linked sites. In this review we examine existing literature aimed at the large-scale protein cross-linking and discuss possible paths for improvement. We also discuss short-length cross-linkers of broad specificity such as formaldehyde and diazirine-based photo-cross-linkers. These cross-linkers could potentially capture many types of interactions, without strict requirement for a particular amino-acid to be present at a given protein-protein interface. How these shortlength, broad specificity cross-linkers be applied to proteome-wide studies? We will suggest specific advances in methodology, instrumentation and software that are needed to

  1. Laser electrospray mass spectrometry of adsorbed molecules at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Brady, John J.; Judge, Elizabeth J.; Simon, Kuriakose; Levis, Robert J.

    2010-02-01

    Atmospheric pressure mass analysis of solid phase biomolecules is performed using laser electrospray mass spectrometry (LEMS). A non-resonant femtosecond duration laser pulse vaporizes native samples at atmospheric pressure for subsequent electrospray ionization and transfer into a mass spectrometer. LEMS was used to detect a complex molecule (irinotecan HCl), a complex mixture (cold medicine formulation with active ingredients: acetaminophen, dextromethorphan HBr and doxylamine succinate), and a biological building block (deoxyguanosine) deposited on steel surfaces without a matrix molecule.

  2. Integrating Mass Spectrometry of Intact Protein Complexes into Structural Proteomics

    PubMed Central

    Hyung, Suk-Joon; Ruotolo, Brandon T.

    2013-01-01

    Summary Mass spectrometry analysis of intact protein complexes has emerged as an established technology for assessing the composition and connectivity within dynamic, heterogeneous multiprotein complexes at low concentrations and in the context of mixtures. As this technology continues to move forward, one of the main challenges is to integrate the information content of such intact protein complex measurements with other mass spectrometry approaches in structural biology. Methods such as H/D exchange, oxidative foot-printing, chemical cross-linking, affinity purification, and ion mobility separation add complementary information that allows access to every level of protein structure and organization. Here, we survey the structural information that can be retrieved by such experiments, demonstrate the applicability of integrative mass spectrometry approaches in structural proteomics, and look to the future to explore upcoming innovations in this rapidly-advancing area. PMID:22611037

  3. Laser desorption mass spectrometry for biomolecule detection and its applications

    NASA Astrophysics Data System (ADS)

    Winston Chen, C. H.; Sammartano, L. J.; Isola, N. R.; Allman, S. L.

    2001-08-01

    During the past few years, we developed and used laser desorption mass spectrometry for biomolecule detections. Matrix-assisted laser desorption/ionization (MALDI) was successfully used to detect DNA fragments with the size larger than 3000 base pairs. It was also successfully used to sequence DNA with both enzymatic and chemical degradation methods to produce DNA ladders. We also developed MALDI with fragmentation for direct DNA sequencing for short DNA probes. Since laser desorption mass spectrometry for DNA detection has the advantages of fast speed and no need of labeling, it has a great potential for molecular diagnosis for disease and person identification by DNA fingerprinting. We applied laser desorption mass spectrometry to succeed in the diagnosis of cystic fibrosis and several other nerve degenerative diseases such as Huntington's disease. We also succeeded in demonstrating DNA typing for forensic applications.

  4. Ion mobility–mass spectrometry for structural proteomics

    PubMed Central

    Zhong, Yueyang; Hyung, Suk-Joon; Ruotolo, Brandon T

    2012-01-01

    Ion mobility coupled to mass spectrometry has been an important tool in the fields of chemical physics and analytical chemistry for decades, but its potential for interrogating the structure of proteins and multiprotein complexes has only recently begun to be realized. Today, ion mobility– mass spectrometry is often applied to the structural elucidation of protein assemblies that have failed high-throughput crystallization or NMR spectroscopy screens. Here, we highlight the technology, approaches and data that have led to this dramatic shift in use, including emerging trends such as the integration of ion mobility–mass spectrometry data with more classical (e.g., ‘bottom-up’) proteomics approaches for the rapid structural characterization of protein networks. PMID:22292823

  5. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin

    NASA Astrophysics Data System (ADS)

    Phelan, Vanessa V.; Fang, Jinshu; Dorrestein, Pieter C.

    2015-06-01

    In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors, and natural products) are measured using phenotypic assays. However, advances in mass spectrometry-based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. Although previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reduce pathogenicity, we observed no clear decrease in specialized metabolite production.

  6. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated With Azithromycin

    PubMed Central

    Phelan, Vanessa V.; Fang, Jinshu; Dorrestein, Pieter C.

    2015-01-01

    In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors and natural products) are measured using phenotypic assays. However, advances in mass spectrometry based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. While previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reducing pathogenicity, we observed no clear decrease in specialized metabolite production. PMID:25801585

  7. Automated protein-ligand interaction screening by mass spectrometry.

    PubMed

    Maple, Hannah J; Garlish, Rachel A; Rigau-Roca, Laura; Porter, John; Whitcombe, Ian; Prosser, Christine E; Kennedy, Jeff; Henry, Alistair J; Taylor, Richard J; Crump, Matthew P; Crosby, John

    2012-01-26

    Identifying protein-ligand binding interactions is a key step during early-stage drug discovery. Existing screening techniques are often associated with drawbacks such as low throughput, high sample consumption, and dynamic range limitations. The increasing use of fragment-based drug discovery (FBDD) demands that these techniques also detect very weak interactions (mM K(D) values). This paper presents the development and validation of a fully automated screen by mass spectrometry, capable of detecting fragment binding into the millimolar K(D) range. Low sample consumption, high throughput, and wide dynamic range make this a highly attractive, orthogonal approach. The method was applied to screen 157 compounds in 6 h against the anti-apoptotic protein target Bcl-x(L). Mass spectrometry results were validated using STD-NMR, HSQC-NMR, and ITC experiments. Agreement between techniques suggests that mass spectrometry offers a powerful, complementary approach for screening. PMID:22148839

  8. Measuring doubly 13C-substituted ethane by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Clog, M.; Ling, C.; Eiler, J. M.

    2012-12-01

    Ethane (C2H6) is present in non-negligible amounts in most natural gas reservoirs and is used to produce ethylene for petrochemical industries. It is one of the by-products of lipid metabolism and is the arguably simplest molecule that can manifest multiple 13C substitutions. There are several plausible controls on the relative abundances of 13C2H6 in natural gases: thermodynamically controlled homogeneous isotope exchange reactions analogous to those behind carbonate clumped isotope thermometry; inheritance from larger biomolecules that under thermal degradation to produce natural gas; mixing of natural gases that differ markedly in bulk isotopic composition; or combinations of these and/or other, less expected fractionations. There is little basis for predicting which of these will dominate in natural samples. Here, we focus on an analytical techniques that will provide the avenue for exploring these phenomena. The method is based on high-resolution gas source isotope ratio mass spectrometry, using the Thermo 253-Ultra (a new prototype mass spectrometer). This instrument achieves the mass resolution (M/Δ M) up to 27,000, permitting separation of the isobaric interferences of potential contaminants and isotopologues of an analtye or its fragments which share a cardinal mass. We present techniques to analyze several isotopologues of molecular and fragment ions of C2H6. The critical isobaric separations for our purposes include: discrimination of 13C2H6 from 13C12CDH5 at mass 32 and separation of the 13CH3 fragment from 12CH4 at mass 16, both requiring at least a mass resolution of 20000 to make an adequate measurement. Other obvious interferences are either cleanly separated (e.g., O2, O) or accounted for by peak-stripping (CH3OH on mass 32 and NH2 on mass 16). We focus on a set of measurements which constrain: the doubly-substituted isotopologue, 13C2H6, and the 13CH3/12CH3 ratio of the methyl fragment, which constrains the bulk δ 13C. Similar methods can be

  9. Gas Chromatography and Mass Spectrometry Measurements and Protocols for Database and Library Development Relating to Organic Species in Support of the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Misra, P.; Garcia, R.; Mahaffy, P. R.

    2010-04-01

    An organic contaminant database and library has been developed for use with the Sample Analysis at Mars (SAM) instrumentation utilizing laboratory-based Gas Chromatography-Mass Spectrometry measurements of pyrolyzed and baked material samples.

  10. Laser desorption mass spectrometry for DNA analysis and sequencing

    SciTech Connect

    Chen, C.H.; Taranenko, N.I.; Tang, K.; Allman, S.L.

    1995-03-01

    Laser desorption mass spectrometry has been considered as a potential new method for fast DNA sequencing. Our approach is to use matrix-assisted laser desorption to produce parent ions of DNA segments and a time-of-flight mass spectrometer to identify the sizes of DNA segments. Thus, the approach is similar to gel electrophoresis sequencing using Sanger`s enzymatic method. However, gel, radioactive tagging, and dye labeling are not required. In addition, the sequencing process can possibly be finished within a few hundred microseconds instead of hours and days. In order to use mass spectrometry for fast DNA sequencing, the following three criteria need to be satisfied. They are (1) detection of large DNA segments, (2) sensitivity reaching the femtomole region, and (3) mass resolution good enough to separate DNA segments of a single nucleotide difference. It has been very difficult to detect large DNA segments by mass spectrometry before due to the fragile chemical properties of DNA and low detection sensitivity of DNA ions. We discovered several new matrices to increase the production of DNA ions. By innovative design of a mass spectrometer, we can increase the ion energy up to 45 KeV to enhance the detection sensitivity. Recently, we succeeded in detecting a DNA segment with 500 nucleotides. The sensitivity was 100 femtomole. Thus, we have fulfilled two key criteria for using mass spectrometry for fast DNA sequencing. The major effort in the near future is to improve the resolution. Different approaches are being pursued. When high resolution of mass spectrometry can be achieved and automation of sample preparation is developed, the sequencing speed to reach 500 megabases per year can be feasible.

  11. Expert systems technology applied to instrument operation and data acquisition of a triple quadrupole mass spectrometer (TQMS)

    SciTech Connect

    Wong, C.M.

    1984-01-01

    This presentation covers the work done at Lawrence Livermore National Laboratory by some computer programmers and analytical chemists specializing in mass spectrometry to develop an expert system for real-time tuning and optimization of operations of a triple quadrupole mass spectrometer (TQMS). This capability is important to increase the sensitivity possible for selected compounds throughout the entire mass range of the instrument, rather than settling for the traditional normalized calibration which lowers sensitivity at both ends of the mass scale.

  12. Microbeam titanium isotopic analysis by resonance ionization mass spectrometry

    SciTech Connect

    Spiegel, D.R.; Davis, A.M.; Clayton, R.N. . Enrico Fermi Inst.); Pellin, M.J.; Calaway, W.F.; Burnett, J.W.; Coon, S.R.; Young, C.E.; Gruen, D.M. )

    1991-01-01

    The importance of isotopic anomalies in refractory inclusions in meteorites is well established. Measurements of the anomalies using conventional mass spectrometry are often rendered difficult, however, by isobarically interfering isotopes: for example, {sup 48}Ti and {sup 48}Ca. Resonance ionization mass spectrometry (RIMS) can substantially reduce isobaric interferences in a number of systems. We have employed RIMS for the in situ detection of Ti atoms sputtered from pure Ti metal and from several terrestrial oxides containing both Ti and Ca. Tunable lasers were employed to resonantly ionize neutral Ti atoms. We have chosen Ti specifically because of the importance of Ti isotopic anomalies in cosmochemistry.

  13. Determination of water content using mass spectrometry

    NASA Technical Reports Server (NTRS)

    Wood, G. M.; Upchurch, B. T.; Hughes, D. B.

    1975-01-01

    Mass spectrometer is used to measure small quantities of water present in different materials. System has been applied in measuring water and gases desorbed from microcircuitry insulation, can also be used with foods, polymeric materials, and organic solvents.

  14. Tropopsheric Aerosol Chemistry via Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Worsnop, Douglas

    2008-03-01

    A broad overview of size resolved aerosol chemistry in urban, rural and remote regions is evolving from deployment of aerosol mass spectrometers (AMS) throughout the northern hemisphere. Using thermal vaporization and electron impact ionization as universal detector of non-refractory inorganic and organic composition, the accumulation of AMS results represent a library of mass spectral signatures of aerosol chemistry. For organics in particular, mass spectral factor analysis provides a procedure for classifying (and simplifying) complex mixtures composed of the hundreds or thousands of individual compounds. Correlations with parallel gas and aerosol measurements (e.g. GC/MS, HNMR, FTIR) supply additional chemical information needed to interpret mass spectra. The challenge is to separate primary and secondary; anthropogenic, biogenic and biomass burning sources - and subsequent - transformations of aerosol chemistry and microphysics.

  15. Dynamically Multiplexed Ion Mobility Time-of-Flight Mass Spectrometry

    PubMed Central

    Belov, Mikhail E.; Clowers, Brian H.; Prior, David C.; Danielson, William F.; Liyu, Andrei V.; Petritis, Brianne O.; Smith, Richard D.

    2010-01-01

    Ion Mobility Spectrometry–Time-of-Flight Mass Spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity high-throughput platform for e.g. proteomics applications. In this work, we have developed and integrated three advanced technologies, including efficient ion accumulation in the ion funnel trap prior to IMS separation, multiplexing (MP) of ion packet introduction into the IMS drift tube and signal detection with an analog-to-digital converter (ADC), into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of e.g. blood plasma. To better address variable sample complexity, we have developed and rigorously evaluated a novel dynamic MP approach that ensures correlation of the analyzer performance with an ion source function, and provides the improved dynamic range and sensitivity throughout the experiment. The MP IMS-TOF MS instrument has been shown to reliably detect peptides at a concentration of 1 nM in the presence of highly complex matrix, as well as to provide a three orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features were found to yield ~ 700 unique peptide identifications at a false discovery rate (FDR) of ~ 7.5 %. Accounting for IMS information gave rise to a projected FDR of ~ 4 %. Signal reproducibility was found to be greater than 80 %, while the variations in the number of unique peptide identifications were < 15 %. A single sample analysis was completed in 15 min that constitutes almost an order of magnitude improvement compared to a more conventional LC-MS approach. PMID:18582088

  16. Scanning mass spectrometry with integrated constant distance positioning

    SciTech Connect

    Li Nan; Eckhard, Kathrin; Assmann, Jens; Hagen, Volker; Otto, Horst; Chen Xingxing; Schuhmann, Wolfgang; Muhler, Martin

    2006-08-15

    Scanning mass spectrometry is of growing importance for the characterization of catalytically active surfaces. The instrument presented here is capable of measuring catalytic activity spatially resolved by means of two concentric capillaries. The outer one is used for cofeeding reactants such as ethene and hydrogen to the sample surface, whereas the inner one is pumping off the product mixture as inlet to a quadrupole mass spectrometer. Three-dimensional measurements under stagnant-point flow conditions become possible based on a home-built capillary positioning unit. Step-motor driven positioning stages exhibiting a minimum step width of 2.5 {mu}mehalf step are used for the x, y positioning, and the step motor in z direction has a resolution of 1 {mu}mehalf step. The system is additionally equipped with a feedback loop for following the topography of the sample throughout scanning. Hence, the obtained catalytic data are unimpaired by signal changes caused by the morphology of the investigated structure. For distance control the argon ion current is used originating from externally fed argon diffusing into the confined space between the accurately positioned capillaries and the sample surface. A well-defined microchannel flow field with 400 {mu}m wide channels and 200 {mu}m wide mounds was chosen to evaluate the developed method. The catalytic activity of a Pt catalyst deposited on glassy carbon was successfully visualized in constant probe to sample distance. Simultaneously, the topography of the sample was recorded derived from the z positioning of the capillaries.

  17. Dynamically Multiplexed Ion Mobility Time-of-Flight Mass Spectrometry

    SciTech Connect

    Belov, Mikhail E.; Clowers, Brian H.; Prior, David C.; Danielson, William F.; Liyu, Andrei V.; Petritis, Brianne O.; Smith, Richard D.

    2008-08-01

    Ion Mobility Spectrometry–Time-of-Flight Mass Spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity high-throughput platform for e.g. proteomics applications. In this work, we have developed and integrated three advanced technologies, enabling (1) efficient ion accumulation in the ion funnel trap prior to IMS separation, (2) multiplexing (MP) of ion packet introduction into the IMS drift tube and (3) signal detection with an analog-to-digital converter (ADC), into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of e.g. blood plasma. To better address variable sample complexity, we have additionally developed and rigorously evaluated a new dynamic MP approach that ensures correlation of the analyzer performance with an ion source function, and provides the improved dynamic range and sensitivity. The MP IMS-TOF MS instrument has been shown to reliably detect peptides at a concentration of 1 nM in a highly complex matrix, as well as to provide a four orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features yielded ~ 700 unique peptide identifications at a false discovery rate (FDR) of ~ 7.5 %. Accounting for IMS information gave rise to a projected FDR of ~ 4 %. Signal reproducibility was found to be greater than 80 %, while the variations in the number of unique peptide identifications were < 15 %. A single sample analysis was completed in 15 min, corresponding to approximately an order of magnitude improvement compared to a more conventional LC-MS approach.

  18. Histology-directed MALDI mass spectrometry for the diagnostic pathology

    NASA Astrophysics Data System (ADS)

    Kim, Hark Kyun; Kim, In-Hoo

    2012-10-01

    With the advent of targeted agents, it has become clinically important to distinguish histologic types of non-small cell lung cancers (NSCLCs) using biopsy samples. We investigated whether direct tissue matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) analysis on lipid may classify histology of NSCLCs. Twentyone pairs of frozen, resected NSCLCs were analyzed using histology-directed, MALDI MS. 2,5-dihydroxybenzoic acid/α-cyano-4-hydroxycinnamic acid were manually deposited on areas of each tissue section enriched in epithelial cells to identify lipid profiles, and mass spectra were acquired using a MALDI-time of flight instrument. Squamous cell carcinomas and adenocarcinomas, two major histologic types of NSCLC, were found to have different lipid profiles. Discriminatory lipids correctly classified the histology of 80.4% of independent NSCLC surgical tissue samples (41 out of 51) in validation set, suggesting that lipid profiles can classify NSCLCs according to the histologic type. We also found that protein and lipid MALDI MS profiles can classify 30 breast cancers according to the intrinsic subtypes. Immunohistochemistry-defined, luminal, HER2+, and triple-negative tumors demonstrated different protein and lipid profiles, as evidenced by cross validation P values < 0.01. Discriminatory proteins and lipids classified tumors according to the intrinsic subtype with median prediction accuracies of 80.0-81.3% in 100 random test sets. Potential advantages of this label-free approach may include small tissue requirement, relatively rapid procedure, and low reagent cost. Day-today variation of this technology is also acceptable, with the Pearson correlation of 0.95. Taken together, these results suggest the possible clinical utility of histology-directed, lipid and protein MALDI MS.

  19. Structure Determination of Natural Products by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Biemann, Klaus

    2015-07-01

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

  20. Structure Determination of Natural Products by Mass Spectrometry.

    PubMed

    Biemann, Klaus

    2015-01-01

    I review laboratory research on the development of mass spectrometric methodology for the determination of the structure of natural products of biological and medical interest, which I conducted from 1958 to the end of the twentieth century. The methodology was developed by converting small peptides to their corresponding polyamino alcohols to make them amenable to mass spectrometry, thereby making it applicable to whole proteins. The structures of alkaloids were determined by analyzing the fragmentation of a known alkaloid and then using the results to deduce the structures of related compounds. Heparin-like structures were investigated by determining their molecular weights from the mass of protonated molecular ions of complexes with highly basic, synthetic peptides. Mass spectrometry was also employed in the analysis of lunar material returned by the Apollo missions. A miniaturized gas chromatograph mass spectrometer was sent to Mars on board of the two Viking 1976 spacecrafts. PMID:26161970

  1. Laser post-ionization secondary neutral mass spectrometry for ultra-trace analysis of samples from space return missions

    NASA Astrophysics Data System (ADS)

    Veryovkin, Igor V.; Calaway, Wallis F.; Emil Tripa, C.; Moore, Jerry F.; Wucher, Andreas; Pellin, Michael J.

    2005-12-01

    A new generation of secondary neutral mass spectrometry (SNMS) instruments has been developed that is especially designed for laser post-ionization (LPI). These instruments combine high useful yield and high background discrimination. Results presented here demonstrate that these instruments can detect one in every four atoms removed from a samples surface - a greater than one order of magnitude improvement over current large frame secondary ion mass spectrometry instruments. Because of their high sensitivity, these new LPI-SNMS instruments are especially amenable to analysis of samples of limited size and rare one-of-a-kind samples. Such an application is analysis of samples returned to Earth from space by the Genesis and Stardust Discovery missions of NASA.

  2. Mass Spectrometry Imaging, an Emerging Technology in Neuropsychopharmacology

    PubMed Central

    Shariatgorji, Mohammadreza; Svenningsson, Per; Andrén, Per E

    2014-01-01

    Mass spectrometry imaging is a powerful tool for directly determining the distribution of proteins, peptides, lipids, neurotransmitters, metabolites and drugs in neural tissue sections in situ. Molecule-specific imaging can be achieved using various ionization techniques that are suited to different applications but which all yield data with high mass accuracies and spatial resolutions. The ability to simultaneously obtain images showing the distributions of chemical species ranging from metal ions to macromolecules makes it possible to explore the chemical organization of a sample and to correlate the results obtained with specific anatomical features. The imaging of biomolecules has provided new insights into multiple neurological diseases, including Parkinson's and Alzheimer's disease. Mass spectrometry imaging can also be used in conjunction with other imaging techniques in order to identify correlations between changes in the distribution of important chemical species and other changes in the properties of the tissue. Here we review the applications of mass spectrometry imaging in neuroscience research and discuss its potential. The results presented demonstrate that mass spectrometry imaging is a useful experimental method with diverse applications in neuroscience. PMID:23966069

  3. Alignment of capillary electrophoresis-mass spectrometry datasets using accurate mass information.

    PubMed

    Nevedomskaya, Ekaterina; Derks, Rico; Deelder, André M; Mayboroda, Oleg A; Palmblad, Magnus

    2009-12-01

    Capillary electrophoresis-mass spectrometry (CE-MS) is a powerful technique for the analysis of small soluble compounds in biological fluids. A major drawback of CE is the poor migration time reproducibility, which makes it difficult to combine data from different experiments and correctly assign compounds. A number of alignment algorithms have been developed but not all of them can cope with large and irregular time shifts between CE-MS runs. Here we present a genetic algorithm designed for alignment of CE-MS data using accurate mass information. The utility of the algorithm was demonstrated on real data, and the results were compared with one of the existing packages. The new algorithm showed a significant reduction of elution time variation in the aligned datasets. The importance of mass accuracy for the performance of the algorithm was also demonstrated by comparing alignments of datasets from a standard time-of-flight (TOF) instrument with those from the new ultrahigh resolution TOF maXis (Bruker Daltonics). PMID:19826795

  4. New Cs sputter ion source with polyatomic ion beams for secondary ion mass spectrometry applications

    SciTech Connect

    Belykh, S. F.; Palitsin, V. V.; Veryovkin, I. V.; Kovarsky, A. P.; Chang, R. J. H.; Adriaens, A.; Dowsett, M. G.; Adams, F.

    2007-08-15

    A simple design for a cesium sputter ion source compatible with vacuum and ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This ion source has been tested with the cluster primary ions of Si{sub n}{sup -} and Cu{sub n}{sup -}. Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of the analytical capabilities of the secondary ion mass spectrometry instrument due to the nonadditive enhancement of secondary ion emission and shorter ion ranges of polyatomic projectiles compared to atomic ones with the same impact energy.

  5. Signatures for Mass Spectrometry Data Quality

    SciTech Connect

    Amidan, Brett G.; Orton, Daniel J.; Lamarche, Brian L.; Monroe, Matthew E.; Moore, Ronald J.; Venzin, Alexander M.; Smith, Richard D.; Sego, Landon H.; Tardiff, Mark F.; Payne, Samuel H.

    2014-03-10

    Ensuring data quality and proper instrument functionality is a prerequisite for scientific investigation. Manual validation for quality assurance is time consuming, expensive and subjective. Metrics for describing various features of LC-MS data have been developed to assist operators in discriminating poor (out of control) and good (in control) datasets. However, the wide variety of instrument specifications and LC-MS configurations precludes applying a simple range of acceptable values or cutoffs for such metrics. We explored a variety of statistical modeling approaches to predict the quality of LC-MS data. Using 1164 manually classified quality control (QC) LC-MS datasets, we fit logistic regression classification models to the QC data to predict whether a dataset is in or out of control. Model parameters were optimized by minimizing a loss function that accounts for the tradeoff between false positive and false negative errors. The optimal logistic regression classifier models detected bad data sets with high sensitivity (i.e. low false negative rate) while maintaining high specificity (i.e. controlling the false positive rate). As an example, predictions for Velos-Orbitrap instrumentation data had a sensitivity of 93.7% in detecting out of control datasets with a false positive rate of 8.3%. In comparison, we investigated the performance of several single metrics in predicting dataset quality. While maintaining a sensitivity of 93.7%, the corresponding false positive rates for these single-metric models unacceptably ranged from 32% to 97.7%. Finally, we evaluated the performance of the

  6. Examining the Heterogeneous Genome Content of Multipartite Viruses BMV and CCMV by Native Mass Spectrometry.

    PubMed

    van de Waterbeemd, Michiel; Snijder, Joost; Tsvetkova, Irina B; Dragnea, Bogdan G; Cornelissen, Jeroen J; Heck, Albert J R

    2016-06-01

    Since the concept was first introduced by Brian Chait and co-workers in 1991, mass spectrometry of proteins and protein complexes under non-denaturing conditions (native MS) has strongly developed, through parallel advances in instrumentation, sample preparation, and data analysis tools. However, the success rate of native MS analysis, particularly in heterogeneous mega-Dalton (MDa) protein complexes, still strongly depends on careful instrument modification. Here, we further explore these boundaries in native mass spectrometry, analyzing two related endogenous multipartite viruses: the Brome Mosaic Virus (BMV) and the Cowpea Chlorotic Mottle Virus (CCMV). Both CCMV and BMV are approximately 4.6 megadalton (MDa) in mass, of which approximately 1 MDA originates from the genomic content of the virion. Both viruses are produced as mixtures of three particles carrying different segments of the genome, varying by approximately 0.1 MDA in mass (~2%). This mixture of particles poses a challenging analytical problem for high-resolution native MS analysis, given the large mass scales involved. We attempt to unravel the particle heterogeneity using both Q-TOF and Orbitrap mass spectrometers extensively modified for analysis of very large assemblies. We show that manipulation of the charging behavior can provide assistance in assigning the correct charge states. Despite their challenging size and heterogeneity, we obtained native mass spectra with resolved series of charge states for both BMV and CCMV, demonstrating that native MS of endogenous multipartite virions is feasible. Graphical Abstract ᅟ. PMID:26926442

  7. Examining the Heterogeneous Genome Content of Multipartite Viruses BMV and CCMV by Native Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    van de Waterbeemd, Michiel; Snijder, Joost; Tsvetkova, Irina B.; Dragnea, Bogdan G.; Cornelissen, Jeroen J.; Heck, Albert J. R.

    2016-02-01

    Since the concept was first introduced by Brian Chait and co-workers in 1991, mass spectrometry of proteins and protein complexes under non-denaturing conditions (native MS) has strongly developed, through parallel advances in instrumentation, sample preparation, and data analysis tools. However, the success rate of native MS analysis, particularly in heterogeneous mega-Dalton (MDa) protein complexes, still strongly depends on careful instrument modification. Here, we further explore these boundaries in native mass spectrometry, analyzing two related endogenous multipartite viruses: the Brome Mosaic Virus (BMV) and the Cowpea Chlorotic Mottle Virus (CCMV). Both CCMV and BMV are approximately 4.6 megadalton (MDa) in mass, of which approximately 1 MDA originates from the genomic content of the virion. Both viruses are produced as mixtures of three particles carrying different segments of the genome, varying by approximately 0.1 MDA in mass (~2%). This mixture of particles poses a challenging analytical problem for high-resolution native MS analysis, given the large mass scales involved. We attempt to unravel the particle heterogeneity using both Q-TOF and Orbitrap mass spectrometers extensively modified for analysis of very large assemblies. We show that manipulation of the charging behavior can provide assistance in assigning the correct charge states. Despite their challenging size and heterogeneity, we obtained native mass spectra with resolved series of charge states for both BMV and CCMV, demonstrating that native MS of endogenous multipartite virions is feasible.

  8. Examining the Heterogeneous Genome Content of Multipartite Viruses BMV and CCMV by Native Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    van de Waterbeemd, Michiel; Snijder, Joost; Tsvetkova, Irina B.; Dragnea, Bogdan G.; Cornelissen, Jeroen J.; Heck, Albert J. R.

    2016-06-01

    Since the concept was first introduced by Brian Chait and co-workers in 1991, mass spectrometry of proteins and protein complexes under non-denaturing conditions (native MS) has strongly developed, through parallel advances in instrumentation, sample preparation, and data analysis tools. However, the success rate of native MS analysis, particularly in heterogeneous mega-Dalton (MDa) protein complexes, still strongly depends on careful instrument modification. Here, we further explore these boundaries in native mass spectrometry, analyzing two related endogenous multipartite viruses: the Brome Mosaic Virus (BMV) and the Cowpea Chlorotic Mottle Virus (CCMV). Both CCMV and BMV are approximately 4.6 megadalton (MDa) in mass, of which approximately 1 MDA originates from the genomic content of the virion. Both viruses are produced as mixtures of three particles carrying different segments of the genome, varying by approximately 0.1 MDA in mass (~2%). This mixture of particles poses a challenging analytical problem for high-resolution native MS analysis, given the large mass scales involved. We attempt to unravel the particle heterogeneity using both Q-TOF and Orbitrap mass spectrometers extensively modified for analysis of very large assemblies. We show that manipulation of the charging behavior can provide assistance in assigning the correct charge states. Despite their challenging size and heterogeneity, we obtained native mass spectra with resolved series of charge states for both BMV and CCMV, demonstrating that native MS of endogenous multipartite virions is feasible.

  9. The evolving field of imaging mass spectrometry and its impact on future biological research

    PubMed Central

    Watrous, Jeramie D.; Alexandrov, Theodore; Dorrestein, Pieter C.

    2012-01-01

    Within the past decade, imaging mass spectrometry has been increasingly recognized as an indispensable technique for studying biological systems. Its rapid evolution has resulted in an impressive array of instrument variations and sample applications, yet the tools and data are largely confined to specialists. It is therefore important that at this junction the IMS community begin to establish IMS as a permanent fixture in life sciences research thereby making the technology and/or the data approachable by non-mass spectrometrists, leading to further integration into biological and clinical research. In this perspective article, we provide insight into the evolution and current state of imaging mass spectrometry and propose some of the directions that IMS could develop in order to stay on course to become one of the most promising new tools in life science research. PMID:21322093

  10. A New Accelerator-Based Mass Spectrometry.

    ERIC Educational Resources Information Center

    Gove, H. E.

    1983-01-01

    Tandem electrostatic accelerators produce beams of positive ions which are used to penetrate atomic nuclei in a target, inducing nuclear reactions whose study elucidates varied properties of the nucleus. Uses of the system, which acts like a mass spectrometer, are discussed. These include radiocarbon dating measurements. (JN)

  11. ALTERNATIVE IONIZATION METHODS FOR PARTICLE MASS SPECTROMETRY

    EPA Science Inventory

    The objective of this project is to enhance the capabilities of a real-time airborne particle mass spectrometer by implementing matrix-independent methods for sample ionization. The enhancements should result in improved sensitivity for trace substances and, more importantly, per...

  12. Comparative analysis of dioxins and furans by electron impact, high-resolution mass spectrometry and by electron capture, negative ionization, low-resolution mass spectrometry

    SciTech Connect

    Koester, C.J.; Harless, R.L.; Hites, R.A.

    1990-01-01

    Electron impact, high resolution mass spectrometry (HRMS) is currently the method of choice for the analysis of polychlorinated dibenso-p-dioxins and dibenzofurans (PCDD/F) because of its ability to detect PCDD/F in the presence of interfering compounds, such as polychlorinated biphenyls (PCB), which cannot be resolved by low resolution methods. The PDCC/F analyses may also be performed using electron capture, negative ionization (ECNI) low resolution mass spectrometry, providing extensive sample preparation is done to remove interferences. Before ECNI low resolution mass spectrometry (MS) can be accepted as a routine method for PCDD/F analysis, it is necessary to show that results generated by this method are comparable to those obtained by HRMS. Known mixtures and unknown air samples were analyzed by electron impact HRMS (Finnigan MAT 90 system) and by ECNI low resolution MS (Hewlett Packard 5985B). Both instruments were fitted with a gas chromatographic inlet. The PCDD/F concentrations determined by the two techniques compare favorably, typically within 20%. The major difference between these two methods is that the ECNI low resolution method shows poor sensitivity in detecting 2,3,7,8-tetrachlorodioxin. However, ECNI MS offers the advantage of lower detection limits (50-100 fg) than electron impact HRMS (0.1 to 0.5 pg). These results suggest that ECNI low resolution MS can be a simple, low cost alternative to the common high resolution methods used for PCDD/F analysis.

  13. Characterization of plant materials by pyrolysis-field ionization mass spectrometry: high-resolution mass spectrometry, time-resolved high-resolution mass spectrometry, and Curie-point pyrolysis-gas chromatography/mass spectrometry of spruce needles

    SciTech Connect

    Schulten, H.F.; Simmleit, N.; Mueller, R.

    1989-02-01

    In the course of a forest damage research project spruce needles are analyzed, without pretreatment except drying and milling, by in-source pyrolysis-field ionization mass spectrometry. The mass signals are assigned by using high-resolution mass measurements and thermal degradation products identified by Curie-point pyrolysis-gas chromatography. It is demonstrated that the thermal degradation products characterize the main chemical constituents of spruce needs such as polysaccharides and lignin. Furthermore, thermostable constituents such as lipids, steroids, and flavons are detected. The thermal degradation process is studied by temperature-programmed microfurnace pyrolysis in combination with time-resolved high-resolution mass spectrometry. The integrated interpretation of results achieved by the presented methods can be applied for the universal characterization of complex and in particular nonsoluble, polydisperse biological and geochemical materials.

  14. Investigation of protein-ligand interactions by mass spectrometry.

    PubMed

    Sinz, Andrea

    2007-04-01

    The rate of drug discovery is greatly dependent on the development and improvement of rapid and reliable analytical methods that allow screening for protein-ligand interactions. The solution-based methods for investigating protein-ligand interactions by mass spectrometry (MS), which are discussed in this paper, are hydrogen/deuterium exchange of protein backbone amide hydrogens, and photoaffinity labeling. Moreover, MS analysis of intact noncovalent protein-ligand complexes is described. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) with its ultra-high resolution and excellent mass accuracy is also considered herein as it is gaining increasing popularity for a mass spectrometric investigation of protein-ligand interactions. PMID:17299828

  15. A new derivative for oxosteroid analysis by mass spectrometry

    PubMed Central

    Rigdova, K.; Wang, Y.; Ward, M.; Griffiths, W.J.

    2014-01-01

    Here we report a new method for oxosteroid identification utilizing “tandem mass tag hydrazine” (TMTH) carbonyl-reactive derivatisation reagent. TMTH is a reagent with a chargeable tertiary amino group attached through a linker to a carbonyl-reactive hydrazine group. Thirty oxosteroids were analysed after derivatisation with TMTH by electrospray ionization mass spectrometry (ESI-MS) and were found to give high ion-currents compared to underivatised molecules. ESI-tandem mass spectrometry (MS/MS) analysis of the derivatives yielded characteristic fragmentation patterns with specific mass reporter ions derived from the TMT group. A shotgun ESI-MS method incorporating TMTH derivatisation was applied to a urine sample. PMID:24525129

  16. Mass Spectrometry Imaging of Biological Tissue: An Approach for Multicenter Studies

    SciTech Connect

    Rompp, Andreas; Both, Jean-Pierre; Brunelle, Alain; Heeren, Ronald M.; Laprevote, Olivier; Prideaux, Brendan; Seyer, Alexandre; Spengler, Bernhard; Stoeckli, Markus; Smith, Donald F.

    2015-03-01

    Mass spectrometry imaging has become a popular tool for probing the chemical complexity of biological surfaces. This led to the development of a wide range of instrumentation and preparation protocols. It is thus desirable to evaluate and compare the data output from different methodologies and mass spectrometers. Here, we present an approach for the comparison of mass spectrometry imaging data from different laboratories (often referred to as multicenter studies). This is exemplified by the analysis of mouse brain sections in five laboratories in Europe and the USA. The instrumentation includes matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF), MALDI-QTOF, MALDIFourier transform ion cyclotron resonance (FTICR), atmospheric-pressure (AP)-MALDI-Orbitrap, and cluster TOF-secondary ion mass spectrometry (SIMS). Experimental parameters such as measurement speed, imaging bin width, and mass spectrometric parameters are discussed. All datasets were converted to the standard data format imzML and displayed in a common open-source software with identical parameters for visualization, which facilitates direct comparison of MS images. The imzML conversion also allowed exchange of fully functional MS imaging datasets between the different laboratories. The experiments ranged from overview measurements of the full mouse brain to detailed analysis of smaller features (depending on spatial resolution settings), but common histological features such as the corpus callosum were visible in all measurements. High spatial resolution measurements of AP-MALDI-Orbitrap and TOF-SIMS showed comparable structures in the low-micrometer range. We discuss general considerations for planning and performing multicenter studies in mass spectrometry imaging. This includes details on the selection, distribution, and preparation of tissue samples as well as on data handling. Such multicenter studies in combination with ongoing activities for reporting guidelines, a common

  17. Absorption Mode FT-ICR Mass Spectrometry Imaging

    SciTech Connect

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

    2013-12-03

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

  18. High-accuracy mass spectrometry for fundamental studies.

    PubMed

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions. PMID:20530821

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

    PubMed Central

    Laughlin, Sarah; Wilson, W. David

    2015-01-01

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

  20. Quantitative matrix-assisted laser desorption/ionization mass spectrometry

    PubMed Central

    Roder, Heinrich; Hunsucker, Stephen W.

    2008-01-01

    This review summarizes the essential characteristics of matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF MS), especially as they relate to its applications in quantitative analysis. Approaches to quantification by MALDI-TOF MS are presented and published applications are critically reviewed. PMID:19106161

  1. Mass spectrometry-based detection of protein acetylation

    PubMed Central

    Li, Yu; Silva, Jeffrey C.; Skinner, Mary E.; Lombard, David B.

    2014-01-01

    Summary Improved sample preparation techniques and increasingly sensitive mass spectrometry (MS) analysis have revolutionized the study of protein post-translational modifications (PTMs). Here, we describe a general approach for immunopurification and MS-based identification of acetylated proteins in biological samples. This approach is useful characterizing changes in the acetylome in response to biological interventions (1). PMID:24014401

  2. MASS SPECTROMETRY OF INDIVIDUAL AEROSOL PARTICLES. (R823980)

    EPA Science Inventory

    Typically, in real-time aerosol mass spectrometry (RTAMS), individual airborne particles
    are ablated and ionized with a single focused laser pulse. This technique yields information that
    permits bulk characterization of the particle, but information about the particle's sur...

  3. On-Line Synthesis and Analysis by Mass Spectrometry

    ERIC Educational Resources Information Center

    Bain, Ryan M.; Pulliam, Christopher J.; Raab, Shannon A.; Cooks, R. Graham

    2015-01-01

    In this laboratory experiment, students learn how to use ESI to accelerate chemical synthesis and to couple it with on-line mass spectrometry for structural analysis. The Hantzsch synthesis of symmetric 1,4-dihydropyridines is a classic example of a one-pot reaction in which multiple intermediates can serve to indicate the progress of the reaction…

  4. MICELLAR ELECTROKINETIC CHROMATOGRAPHY-MASS SPECTROMETRY (R823292)

    EPA Science Inventory

    The combination of micellar electrokinetic chromatography (MEKC) with mass spectrometry (MS) is very attractive for the direct identification of analyte molecules, for the possibility of selectivity enhancement, and for the structure confirmation and analysis in a MS-MS mode. The...

  5. Coming to a hospital near you: mass spectrometry imaging

    ScienceCinema

    Bowen, Ben

    2014-06-24

    Berkeley Lab's Ben Bowen discusses "Coming to a hospital near you: mass spectrometry imaging" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas. Go here to watch the entire event with all 8 speakers.

  6. Utility of mass spectrometry in the diagnosis of prion diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a sensitive mass spectrometry-based method of quantitating the prions present in a variety of mammalian species. Calibration curves relating the area ratios of the selected analyte peptides and their oxidized analogs to their homologous stable isotope labeled internal standards were pre...

  7. Diagnosing Prion Diseases: Mass Spectrometry-Based Approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mass spectrometry is an established means of quantitating the prions present in infected hamsters. Calibration curves relating the area ratios of the selected analyte peptides and their oxidized analogs to stable isotope labeled internal standards were prepared. The limit of detection (LOD) and limi...

  8. Mass Spectrometry Based Identifications of LMW Glutenin Subunits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tandem mass spectrometry (MS/MS) is routinely used to identify wheat endosperm proteins. In this method, peptide fragmentation patterns generated by MS/MS are identified using a ‘search engine’ to compare the spectra to those generated in silico from protein sequence databases. Trypsin is a commonly...

  9. Quantification of hydroxyacetone and glycolaldehyde using chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    St. Clair, J. M.; Spencer, K. M.; Beaver, M. R.; Crounse, J. D.; Paulot, F.; Wennberg, P. O.

    2014-04-01

    Chemical ionization mass spectrometry (CIMS) enables online, rapid, in situ detection and quantification of hydroxyacetone and glycolaldehyde. Two different CIMS approaches are demonstrated employing the strengths of single quadrupole mass spectrometry and triple quadrupole (tandem) mass spectrometry. Both methods are generally capable of the measurement of hydroxyacetone, an analyte with known but minimal isobaric interferences. Tandem mass spectrometry provides direct separation of the isobaric compounds glycolaldehyde and acetic acid using distinct, collision-induced dissociation daughter ions. The single quadrupole CIMS measurement of glycolaldehyde was demonstrated during the ARCTAS-CARB (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites - California Air Resources Board) 2008 campaign, while triple quadrupole CIMS measurements of glycolaldehyde and hydroxyacetone were demonstrated during the BEARPEX (Biosphere Effects on Aerosols and Photochemistry Experiment) 2009 campaign. Enhancement ratios of glycolaldehyde in ambient biomass-burning plumes are reported for the ARCTAS-CARB campaign. BEARPEX observations are compared to simple photochemical box model predictions of biogenic volatile organic compound oxidation at the site.

  10. Analysis of proteins using DIGE and MALDI mass spectrometry

    EPA Science Inventory

    In this work the sensitivity of the quantitative proteomics approach 2D-DIGE/MS (twoDimensional Difference Gel Electrophoresis / Mass Spectrometry) was tested by detecting decreasing amounts of a specific protein at the low picomole and sub-picomole range. Sensitivity of the 2D-D...

  11. Multiple parallel mass spectrometry for lipid and vitamin D analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Liquid chromatography (LC) coupled to mass spectrometry (MS) has become the method of choice for analysis of complex lipid samples. Two types of ionization sources have emerged as the most commonly used to couple LC to MS: atmospheric pressure chemical ionization (APCI) and electrospray ionization ...

  12. Liquid Chromatography-Mass Spectrometry-based Quantitative Proteomics

    SciTech Connect

    Xie, Fang; Liu, Tao; Qian, Weijun; Petyuk, Vladislav A.; Smith, Richard D.

    2011-07-22

    Liquid chromatography-mass spectrometry (LC-MS)-based quantitative proteomics has become increasingly applied for a broad range of biological applications due to growing capabilities for broad proteome coverage and good accuracy in quantification. Herein, we review the current LC-MS-based quantification methods with respect to their advantages and limitations, and highlight their potential applications.

  13. Probing the hydrophobic effect of noncovalent complexes by mass spectrometry.

    PubMed

    Bich, Claudia; Baer, Samuel; Jecklin, Matthias C; Zenobi, Renato

    2010-02-01

    The study of noncovalent interactions by mass spectrometry has become an active field of research in recent years. The role of the different noncovalent intermolecular forces is not yet fully understood since they tend to be modulated upon transfer into the gas phase. The hydrophobic effect, which plays a major role in protein folding, adhesion of lipid bilayers, etc., is absent in the gas phase. Here, noncovalent complexes with different types of interaction forces were investigated by mass spectrometry and compared with the complex present in solution. Creatine kinase (CK), glutathione S-transferase (GST), ribonuclease S (RNase S), and leucine zipper (LZ), which have dissociation constants in the nM range, were studied by native nanoelectrospray mass spectrometry (nanoESI-MS) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with chemical cross-linking (XL). Complexes interacting with hydrogen bonds survived the transfer into gas phase intact and were observed by nanoESI-MS. Complexes that are bound largely by the hydrophobic effect in solution were not detected or only at very low intensity. Complexes with mixed polar and hydrophobic interactions were detected by nanoESI-MS, most likely due to the contribution from polar interactions. All noncovalent complexes could easily be studied by XL MALDI-MS, which demonstrates that the noncovalently bound complexes are conserved, and a real "snap-shot" of the situation in solution can be obtained. PMID:19931466

  14. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

    ERIC Educational Resources Information Center

    Gochman, Nathan; And Others

    1979-01-01

    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  15. DMS-prefiltered mass spectrometry for the detection of biomarkers

    NASA Astrophysics Data System (ADS)

    Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.

    2008-04-01

    Technologies based on Differential Mobility Spectrometry (DMS) are ideally matched to rapid, sensitive, and selective detection of chemicals like biomarkers. Biomarkers linked to exposure to radiation, exposure to CWA's, exposure to toxic materials (TICs and TIMs) and to specific diseases are being examined in a number of laboratories. Screening for these types of exposure can be improved in accuracy and greatly speeded up by using DMS-MS instead of slower techniques like LC-MS and GC-MS. We have performed an extensive series of tests with nanospray-DMS-mass spectroscopy and standalone nanospray-DMS obtaining extensive information on chemistry and detectivity. DMS-MS systems implemented with low-resolution, low-cost, portable mass-spectrometry systems are very promising. Lowresolution mass spectrometry alone would be inadequate for the task, but with DMS pre-filtration to suppress interferences, can be quite effective, even for quantitative measurement. Bio-fluids and digests are well suited to ionization by electrospray and detection by mass-spectrometry, but signals from critical markers are overwhelmed by chemical noise from unrelated species, making essential quantitative analysis impossible. Sionex and collaborators have presented data using DMS to suppress chemical noise, allowing detection of cancer biomarkers in 10,000-fold excess of normal products 1,2. In addition, a linear dynamic range of approximately 2,000 has been demonstrated with accurate quantitation 3. We will review the range of possible applications and present new data on DMS-MS biomarker detection.

  16. Coming to a hospital near you: mass spectrometry imaging

    SciTech Connect

    Bowen, Ben

    2013-10-31

    Berkeley Lab's Ben Bowen discusses "Coming to a hospital near you: mass spectrometry imaging" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas. Go here to watch the entire event with all 8 speakers.

  17. Accelerator mass spectrometry as a bioanalytical tool for nutritional research

    SciTech Connect

    Vogel, J.S.; Turteltaub, K.W.

    1997-09-01

    Accelerator Mass Spectrometry is a mass spectrometric method of detecting long-lived radioisotopes without regard to their decay products or half-life. The technique is normally applied to geochronology, but recently has been developed for bioanalytical tracing. AMS detects isotope concentrations to parts per quadrillion, quantifying labeled biochemicals to attomole levels in milligram- sized samples. Its advantages over non-isotopeic and stable isotope labeling methods are reviewed and examples of analytical integrity, sensitivity, specificity, and applicability are provided.

  18. On the structural denaturation of biological analytes in trapped ion mobility spectrometry - mass spectrometry.

    PubMed

    Liu, Fanny C; Kirk, Samuel R; Bleiholder, Christian

    2016-06-01

    Key to native ion mobility/mass spectrometry is to prevent the structural denaturation of biological molecules in the gas phase. Here, we systematically assess structural changes induced in the protein ubiquitin during a trapped ion mobility spectrometry (TIMS) experiment. Our analysis shows that the extent of structural denaturation induced in ubiquitin ions is largely proportional to the amount of translational kinetic energy an ion gains from the applied electric field between two collisions with buffer gas particles. We then minimize the efficiency of the structural denaturation of ubiquitin ions in the gas phase during a TIMS experiment. The resulting "soft" TIMS spectra of ubiquitin are found largely identical to those observed on "soft" elevated-pressure ion mobility drift tubes and the corresponding calibrated cross sections are consistent with structures reported from NMR experiments for the native and A-state of ubiquitin. Thus, our analysis reveals that TIMS is useful for native ion mobility/mass spectrometry analysis. PMID:26998732

  19. Hands-on Electrospray Ionization-Mass Spectrometry for Upper-Level Undergraduate and Graduate Students

    ERIC Educational Resources Information Center

    Stock, Naomi L.; March, Raymond E.

    2014-01-01

    Electrospray ionization-mass spectrometry (ESI-MS) is a powerful technique for the detection, identification, and quantification of organic compounds. As mass spectrometers have become more user-friendly and affordable, many students--often with little experience in mass spectrometry--find themselves needing to incorporate mass spectrometry into…

  20. Mass spectrometry in the U.S. space program: past, present, and future.

    PubMed

    Palmer, P T; Limero, T F

    2001-06-01

    Recent years have witnessed significant progress on the miniaturization of mass spectrometers for a variety of field applications. This article describes the development and application of mass spectrometry (MS) instrumentation to support of goals of the U.S. space program. Its main focus is on the two most common space-related applications of MS: studying the composition of planetary atmospheres and monitoring air quality on manned space missions. Both sets of applications present special requirements in terms of analytical performance (sensitivity, selectivity, speed, etc.), logistical considerations (space, weight, and power requirements), and deployment in perhaps the harshest of all possible environments (space). The MS instruments deployed on the Pioneer Venus and Mars Viking Lander missions are reviewed for the purposes of illustrating the unique features of the sample introduction systems, mass analyzers, and vacuum systems, and for presenting their specifications which are impressive even by today's standards. The various approaches for monitoring volatile organic compounds (VOCs) in cabin atmospheres are also reviewed. In the past, ground-based GC/MS instruments have been used to identify and quantify VOCs in archival samples collected during the Mercury, Apollo, Skylab, Space Shuttle, and Mir missions. Some of the data from the more recent missions are provided to illustrate the composition data obtained and to underscore the need for instrumentation to perform such monitoring in situ. Lastly, the development of two emerging technologies, Direct Sampling Ion Trap Mass Spectrometry (DSITMS) and GC/Ion Mobility Spectrometry (GC/IMS), will be discussed to illustrate their potential utility for future missions. PMID:11401157

  1. Tandem mass spectrometry for sequencing proanthocyanidins.

    PubMed

    Li, Hui-Jing; Deinzer, Max L

    2007-02-15

    Proanthocyanidins (PAs) are a group of bioflavonoids consisting of oligomers based on catechin monomeric units. These polyphenolic compounds are widely distributed in higher plants and are an integral part of the human diet. A sensitive LC-tandem mass spectrometric (LC/ESI-MS(n)) method in the positive ion mode for sequencing these ubiquitous and highly beneficial antioxidants is described. The hydroxylation patterns and interflavanoid linkage for A- and B-type PAs were determined by fragment ions derived from a retro-Diels-Alder (RDA) fission, heterocyclic ring fission (HRF), a novel benzofuran-forming (BFF) fission described here for the first time, and a quinone methide (QM) fission. The subunit sequence of the PAs was determined by diagnostic ions derived from HRF/RDA fission, HRF/BFF fission, and RDA/HRF fission together with QM fission. A total of 26 PAs were reliably sequenced by the newly established tandem mass spectrometric protocol. It is shown that the protocol based on a combination of these different fragmentation patterns allows for uniquely identifying PA oligomers. PMID:17297981

  2. Analysis of Mass Spectrometry Data for Nucleolar Proteomics Experiments.

    PubMed

    Nicolas, Armel; Bensaddek, Dalila; Lamond, Angus I

    2016-01-01

    With recent advances in experiment design, sample preparation, separation and instruments, mass spectrometry (MS)-based quantitative proteomics is becoming increasingly more popular. This has the potential to usher a new revolution in biology, in which the protein complement of cell populations can be described not only with increasing coverage, but also in all of its dimensions with unprecedented precision. Indeed, while earlier proteomics studies aimed solely at identifying as many as possible of the proteins present in the sample, newer, so-called Next Generation Proteomics studies add to this the aim of determining and quantifying the protein variants present in the sample, their mutual associations within complexes, their posttranslational modifications, their variation across the cell-cycle or in response to stimuli or perturbations, and their subcellular distribution. This has the potential to make MS proteomics much more useful for researchers, but will also mean that researchers with no background in MS will increasingly be confronted with the less-than trivial challenges of preparing samples for MS analysis, then processing and interpreting the results. In Chapter 20 , we described a workflow for isolating the protein contents of a specific SILAC-labeled organelle sample (the nucleolus) and processing it into peptides suitable for bottom-up MS analysis. Here, we complete this workflow by describing how to use the freely available MaxQuant software to convert the spectra stored in the Raw files into peptide- and protein-level information. We also briefly describe how to visualize the data using the free R scripting language. PMID:27576726

  3. Mass spectrometry in food proteomics: a tutorial.

    PubMed

    Cunsolo, Vincenzo; Muccilli, Vera; Saletti, Rosaria; Foti, Salvatore

    2014-09-01

    In the last decades, the continuous and rapid evolution of proteomic approaches has provided an efficient platform for the characterization of food-derived proteins. Particularly, the impressive increasing in performance and versatility of the MS instrumentation has contributed to the development of new analytical strategies for proteins, evidencing how MS arguably represents an indispensable tool in food proteomics. Investigation of protein composition in foodstuffs is helpful for understanding the relationship between the protein content and the nutritional and technological properties of foods, the production of methods for food traceability, the assessment of food quality and safety, including the detection of allergens and microbial contaminants in foods, or even the characterization of genetically modified products. Given the high variety of the food-derived proteins and considering their differences in chemical and physical properties, a single proteomic strategy for all purposes does not exist. Rather, proteomic approaches need to be adapted to each analytical problem, and development of new strategies is necessary in order to obtain always the best results. In this tutorial, the most relevant aspects of MS-based methodologies in food proteomics will be examined, and their advantages and drawbacks will be discussed. PMID:25230173

  4. A compact permanent magnet cyclotrino for accelerator mass spectrometry

    SciTech Connect

    Young, A.T.; Clark, D.J.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.

    1995-02-01

    The authors describe the development of a new instrument for the detection of trace amounts of rare isotopes, a Cyclotron Mass Spectrometer (CMS). A compact low energy cyclotron optimized for high mass resolution has been designed and has been fabricated. The instrument has high sensitivity and is designed to measure carbon-14 at abundances of < 10{sup {minus}12}. A novel feature of the instrument is the use of permanent magnets to energize the iron poles of the cyclotron. The instrument uses axial injection, employing a spiral inflector. The instrument has been assembled and preliminary measurements of the magnetic field show that it has a uniformity on the order of 2 parts in 10{sup 4}.

  5. Complete Hexose Isomer Identification with Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Nagy, Gabe; Pohl, Nicola L. B.

    2015-04-01

    The first analytical method is presented for the identification and absolute configuration determination of all 24 aldohexose and 2-ketohexose isomers, including the D and L enantiomers for allose, altrose, galactose, glucose, gulose, idose, mannose, talose, fructose, psicose, sorbose, and tagatose. Two unique fixed ligand kinetic method combinations were discovered to create significant enough energetic differences to achieve chiral discrimination among all 24 hexoses. Each of these 24 hexoses yields unique ratios of a specific pair of fragment ions that allows for simultaneous determination of identification and absolute configuration. This mass spectrometric-based methodology can be readily employed for accurate identification of any isolated monosaccharide from an unknown biological source. This work provides a key step towards the goal of complete de novo carbohydrate analysis.

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

    SciTech Connect

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

    2001-02-15

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

  7. Recent developments in Penning-trap mass spectrometry

    NASA Astrophysics Data System (ADS)

    Block, M.

    2016-06-01

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

  8. Determination of 135Cs by accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    MacDonald, C. M.; Charles, C. R. J.; Zhao, X.-L.; Kieser, W. E.; Cornett, R. J.; Litherland, A. E.

    2015-10-01

    The ratio of anthropogenic 135Cs and 137Cs isotopes is characteristic of a uranium fission source. This research evaluates the technique of isotope dilution (yield tracing) for the purpose of quantifying 135Cs by accelerator mass spectrometry with on-line isobar separation. Interferences from Ba, Zn2, and isotopes of equal mass to charge ratios were successfully suppressed. However, some sample crosstalk from source contamination remains. The transmission and di-fluoride ionization efficiencies of Cs isotopes were found to be 8 × 10-3 and 1.7 × 10-7 respectively. This quantification of 135Cs using yield tracing by accelerator mass spectrometry shows promise for future environmental sample analysis once the issues of sample crosstalk and low efficiency can be resolved.

  9. Identification of metabolites of hexazinone by mass spectrometry.

    PubMed

    Reiser, R W; Belasco, I J; Rhodes, R C

    1983-11-01

    The metabolites of hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione ] obtained in the rat and in plants were identified by mass spectrometry. Rat urine metabolites were identified from direct probe spectra obtained on metabolites separated by thin-layer chromatography. Sugarcane metabolites were identified by gas chromatography mass spectrometry of the trimethylsilyl derivatives. The major metabolic routes were found to be hydroxylation of the cyclohexyl group and demethylation. All identifications were confirmed by synthesis and direct comparison of chromatographic data and mass spectra. Hexazinone is metabolized quickly and extensively in the biological systems studied, and is relatively nonpersistent in the environment. PMID:6661503

  10. LILBID-mass spectrometry of the mitochondrial preprotein translocase TOM

    NASA Astrophysics Data System (ADS)

    Mager, Frauke; Sokolova, Lucie; Lintzel, Julia; Brutschy, Bernhard; Nussberger, Stephan

    2010-11-01

    In the present work we applied a novel mass spectrometry method termed laser-induced liquid bead ion desorption mass spectrometry (LILBID-MS) to the outer mitochondrial membrane protein translocon TOM to analyze its subunit composition and stoichiometry. With TOM core complex, purified at high pH, we demonstrate that a TOM core complex of Neurospora crassa is composed of at least two Tom40 and Tom22 molecules, respectively, and more than five small Tom subunits between 5.5 and 6.4 kDa. We show that the multiprotein complex has a total molecular mass higher than 170 depending on the number of Tom5, Tom6 and Tom7 molecules bound.

  11. Advances in structure elucidation of small molecules using mass spectrometry

    PubMed Central

    Fiehn, Oliver

    2010-01-01

    The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules. Electronic supplementary material The online version of this article (doi:10.1007/s12566-010-0015-9) contains supplementary material, which is available to authorized users. PMID:21289855

  12. A common open representation of mass spectrometry data and its application to proteomics research

    SciTech Connect

    Pedrioli, Patrick G.; Eng, Jimmy K.; Hubley, Robert; Vogelzang, Mathijs; Deutsch, Eric W.; Raught, Brian; Pratt, Brian; Nilsson, Erik; Angeletti, Ruth H.; Apweiler, Rolf; Cheung, Kei; Costello, Catherine E.; Hermjakob, Henning; Huang, Sequin; Julian, Jr., Randall K.; Kapp, Eugene; McComb, Mark E.; Oliver, Stephen G.; Omenn, Gilbert; Paton, Norman W.; Simpson, Richard; Smith, Richard D.; Taylor, Chris F.; Zhu, Weimin; Aebersold, Ruedi

    2004-11-01

    A broad range of mass spectrometers are used in mass spectrometry (MS)-based proteomics research. Each type of instrument possesses a unique design, data system and performance specifications, resulting in strengths and weaknesses for different types of experiments. Unfortunately, the native binary data formats produced by each type of mass spectrometer also differ and are usually proprietary. The diverse, nontransparent nature of the data structure complicates the integration of new instruments into preexisting infrastructure, impedes the analysis, exchange, comparison and publication of results from different experiments and laboratories, and prevents the bioinformatics community from accessing data sets required for software development. Here, we introduce the 'mzXML' format, an open, generic XML (extensible markup language) representation of MS data. We have also developed an accompanying suite of supporting programs. We expect that this format will facilitate data management , interpretation and dissemination in proteomics research.

  13. Precise atomic mass measurements by deflection mass spectrometry

    NASA Astrophysics Data System (ADS)

    Barber, R. C.; Sharma, K. S.

    2003-05-01

    Since its inception nearly 90 years ago by J.J. Thomson, the precise determination of atomic masses by the classical technique of deflecting charged particles in electric and magnetic fields has provided a large body of data on naturally occurring nuclides. Currently, such measurements on stable nuclides have frequently achieved a precision of better than two parts in 10 9 of the mass. A review of the technique, together with a brief summary of the important historical developments in the field of precise atomic mass measurements, will be given. The more recent contributions to this field by the deflection mass spectrometer at the University of Manitoba will be provided as illustrations of the culmination of the techniques used and the applications that have been studied. A brief comparison between this and newer techniques using Penning traps will be presented.

  14. Determination of T-2 and HT-2 toxins from maize by direct analysis in real time mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct analysis in real time (DART) ionization coupled to mass spectrometry (MS) was used for the rapid quantitative analysis of T-2 toxin, and the related HT-2 toxin, extracted from corn. Sample preparation procedures and instrument parameters were optimized to obtain sensitive and accurate determi...

  15. Microscale mass spectrometry systems, devices and related methods

    DOEpatents

    Ramsey, John Michael

    2016-06-21

    Mass spectrometry systems or assemblies therefore include an ionizer that includes at least one planar conductor, a mass analyzer with a planar electrode assembly, and a detector comprising at least one planar conductor. The ionizer, the mass analyzer and the detector are attached together in a compact stack assembly. The stack assembly has a perimeter that bounds an area that is between about 0.01 mm.sup.2 to about 25 cm.sup.2 and the stack assembly has a thickness that is between about 0.1 mm to about 25 mm.

  16. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, M.L.; Davis, J.C.

    1993-02-23

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  17. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, Mark L.; Davis, Jay C.

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  18. Data Analysis Methods for Synthetic Polymer Mass Spectrometry: Autocorrelation

    PubMed Central

    Wallace, William E.; Guttman, Charles M.

    2002-01-01

    Autocorrelation is shown to be useful in describing the periodic patterns found in high- resolution mass spectra of synthetic polymers. Examples of this usefulness are described for a simple linear homopolymer to demonstrate the method fundamentals, a condensation polymer to demonstrate its utility in understanding complex spectra with multiple repeating patterns on different mass scales, and a condensation copolymer to demonstrate how it can elegantly and efficiently reveal unexpected phenomena. It is shown that using autocorrelation to determine where the signal devolves into noise can be useful in determining molecular mass distributions of synthetic polymers, a primary focus of the NIST synthetic polymer mass spectrometry effort. The appendices describe some of the effects of transformation from time to mass space when time-of-flight mass separation is used, as well as the effects of non-trivial baselines on the autocorrelation function.

  19. Measuring Thermodynamic Properties of Metals and Alloys With Knudsen Effusion Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Copland, Evan H.; Jacobson, Nathan S.

    2010-01-01

    This report reviews Knudsen effusion mass spectrometry (KEMS) as it relates to thermodynamic measurements of metals and alloys. First, general aspects are reviewed, with emphasis on the Knudsen-cell vapor source and molecular beam formation, and mass spectrometry issues germane to this type of instrument are discussed briefly. The relationship between the vapor pressure inside the effusion cell and the measured ion intensity is the key to KEMS and is derived in detail. Then common methods used to determine thermodynamic quantities with KEMS are discussed. Enthalpies of vaporization, the fundamental measurement, are determined from the variation of relative partial pressure with temperature using the second-law method or by calculating a free energy of formation and subtracting the entropy contribution using the third-law method. For single-cell KEMS instruments, measurements can be used to determine the partial Gibbs free energy if the sensitivity factor remains constant over multiple experiments. The ion-current ratio method and dimer-monomer method are also viable in some systems. For a multiple-cell KEMS instrument, activities are obtained by direct comparison with a suitable component reference state or a secondary standard. Internal checks for correct instrument operation and general procedural guidelines also are discussed. Finally, general comments are made about future directions in measuring alloy thermodynamics with KEMS.

  20. Metabolomics by Gas Chromatography-Mass Spectrometry: Combined Targeted and Untargeted Profiling.

    PubMed

    Fiehn, Oliver

    2016-01-01

    Gas chromatography-mass spectrometry (GC-MS)-based metabolomics is ideal for identifying and quantitating small-molecule metabolites (<650 Da), including small acids, alcohols, hydroxyl acids, amino acids, sugars, fatty acids, sterols, catecholamines, drugs, and toxins, often using chemical derivatization to make these compounds sufficiently volatile for gas chromatography. This unit shows how GC-MS-based metabolomics allows integration of targeted assays for absolute quantification of specific metabolites with untargeted metabolomics to discover novel compounds. Complemented by database annotations using large spectral libraries and validated standard operating procedures, GC-MS can identify and semiquantify over 200 compounds from human body fluids (e.g., plasma, urine, or stool) per study. Deconvolution software enables detection of more than 300 additional unidentified signals that can be annotated through accurate mass instruments with appropriate data processing workflows, similar to untargeted profiling using liquid chromatography-mass spectrometry. GC-MS is a mature technology that uses not only classic detectors (quadrupole) but also target mass spectrometers (triple quadrupole) and accurate mass instruments (quadrupole-time of flight). This unit covers sample preparation from mammalian samples, data acquisition, quality control, and data processing. © 2016 by John Wiley & Sons, Inc. PMID:27038389

  1. Chemically assisted laser ablation ICP mass spectrometry.

    PubMed

    Hirata, Takafumi

    2003-01-15

    A new laser ablation technique combined with a chemical evaporation reaction has been developed for elemental ratio analysis of solid samples using an inductively coupled plasma mass spectrometer (ICPMS). Using a chemically assisted laser ablation (CIA) technique developed in this study, analytical repeatability of the elemental ratio measurement was successively improved. To evaluate the reliability of the CLA-ICPMS technique, Pb/U isotopic ratios were determined for zircon samples that have previously been analyzed by other techniques. Conventional laser ablation for Pb/U shows a serious elemental fractionation during ablation mainly due to the large difference in elemental volatility between Pb and U. In the case of Pb/U ratio measurement, a Freon R-134a gas (1,1,1,2-tetrafluoroethane) was introduced into the laser cell as a fluorination reactant. The Freon gas introduced into the laser cell reacts with the ablated sample U, and refractory U compounds are converted to a volatile U fluoride compound (UF6) under the high-temperature condition at the ablation site. This avoids the redeposition of U around the ablation pits. Although not all the U is reacted with Freon, formation of volatile UF compounds improves the transmission efficiency of U. Typical precision of the 206Pb/238U ratio measurement is 3-5% (2sigma) for NIST SRM 610 and Nancy 91500 zircon standard, and the U-Pb age data obtained here show good agreement within analytical uncertainties with the previously reported values. Since the observed Pb/U ratio for solid samples is relatively insensitive to laser power and ablation time, optimization of ablation conditions or acquisition parameters no longer needs to be performed on a sample-to-sample basis. PMID:12553756

  2. Mass Spectrometry Parameters Optimization for the 46 Multiclass Pesticides Determination in Strawberries with Gas Chromatography Ion-Trap Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Fernandes, Virgínia C.; Vera, Jose L.; Domingues, Valentina F.; Silva, Luís M. S.; Mateus, Nuno; Delerue-Matos, Cristina

    2012-12-01

    Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or " q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

  3. Ambient aerosol analysis using aerosol-time-of-flight mass spectrometry

    SciTech Connect

    Prather, K.A.; Noble, C.A.; Liu, D.Y.; Silva, P.J.; Fergenson, D.F.

    1996-10-01

    We have recently developed a technique, Aerosol-Time-of-Flight Mass Spectrometry (ATOFMS), which is capable of real-time determination of the aerodynamic size and chemical composition of individual aerosol particles. In order to obtain such information, the techniques of aerodynamic particle sizing and time-of-flight mass spectrometry are combined in a single instrument. ATOFMS is being used for the direct analysis of ambient aerosols with the goal of establishing correlations between particle size and chemical composition. Currently, measurements are being made to establish potential links between the presence of particular types of particles with such factors as the time of day, weather conditions, and concentration levels of gaseous smog components such as NO{sub x} and ozone. This data will be used to help establish a better understanding of tropospheric gas-aerosol processes. This talk will discuss the operating principles of ATOFMS as well as present the results of ambient analysis studies performed in our laboratory.

  4. Accelerator mass spectrometry-enabled studies: current status and future prospects

    PubMed Central

    Arjomand, Ali

    2010-01-01

    Accelerator mass spectrometry is a detection platform with exceptional sensitivity compared with other bioanalytical platforms. Accelerator mass spectrometry (AMS) is widely used in archeology for radiocarbon dating applications. Early exploration of the biological and pharmaceutical applications of AMS began in the early 1990s. AMS has since demonstrated unique problem-solving ability in nutrition science, toxicology and pharmacology. AMS has also enabled the development of new applications, such as Phase 0 microdosing. Recent development of AMS-enabled applications has transformed this novelty research instrument to a valuable tool within the pharmaceutical industry. Although there is now greater awareness of AMS technology, recognition and appreciation of the range of AMS-enabled applications is still lacking, including study-design strategies. This review aims to provide further insight into the wide range of AMS-enabled applications. Examples of studies conducted over the past two decades will be presented, as well as prospects for the future of AMS. PMID:20440378

  5. Ion mobility tandem mass spectrometry enhances performance of bottom-up proteomics.

    PubMed

    Helm, Dominic; Vissers, Johannes P C; Hughes, Christopher J; Hahne, Hannes; Ruprecht, Benjamin; Pachl, Fiona; Grzyb, Arkadiusz; Richardson, Keith; Wildgoose, Jason; Maier, Stefan K; Marx, Harald; Wilhelm, Mathias; Becher, Isabelle; Lemeer, Simone; Bantscheff, Marcus; Langridge, James I; Kuster, Bernhard

    2014-12-01

    One of the limiting factors in determining the sensitivity of tandem mass spectrometry using hybrid quadrupole orthogonal acceleration time-of-flight instruments is the duty cycle of the orthogonal ion injection system. As a consequence, only a fraction of the generated fragment ion beam is collected by the time-of-flight analyzer. Here we describe a method utilizing postfragmentation ion mobility spectrometry of peptide fragment ions in conjunction with mobility time synchronized orthogonal ion injection leading to a substantially improved duty cycle and a concomitant improvement in sensitivity of up to 10-fold for bottom-up proteomic experiments. This enabled the identification of 7500 human proteins within 1 day and 8600 phosphorylation sites within 5 h of LC-MS/MS time. The method also proved powerful for multiplexed quantification experiments using tandem mass tags exemplified by the chemoproteomic interaction analysis of histone deacetylases with Trichostatin A. PMID:25106551

  6. Ion Mobility Tandem Mass Spectrometry Enhances Performance of Bottom-up Proteomics

    PubMed Central

    Helm, Dominic; Vissers, Johannes P. C.; Hughes, Christopher J.; Hahne, Hannes; Ruprecht, Benjamin; Pachl, Fiona; Grzyb, Arkadiusz; Richardson, Keith; Wildgoose, Jason; Maier, Stefan K.; Marx, Harald; Wilhelm, Mathias; Becher, Isabelle; Lemeer, Simone; Bantscheff, Marcus; Langridge, James I.; Kuster, Bernhard

    2014-01-01

    One of the limiting factors in determining the sensitivity of tandem mass spectrometry using hybrid quadrupole orthogonal acceleration time-of-flight instruments is the duty cycle of the orthogonal ion injection system. As a consequence, only a fraction of the generated fragment ion beam is collected by the time-of-flight analyzer. Here we describe a method utilizing postfragmentation ion mobility spectrometry of peptide fragment ions in conjunction with mobility time synchronized orthogonal ion injection leading to a substantially improved duty cycle and a concomitant improvement in sensitivity of up to 10-fold for bottom-up proteomic experiments. This enabled the identification of 7500 human proteins within 1 day and 8600 phosphorylation sites within 5 h of LC-MS/MS time. The method also proved powerful for multiplexed quantification experiments using tandem mass tags exemplified by the chemoproteomic interaction analysis of histone deacetylases with Trichostatin A. PMID:25106551

  7. A New Bessel-Box Energy Analyzer for Sputtered Neutral Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Hideki; Shimizu, Ryuichi

    1990-02-01

    A new type energy analyzer with an electron impact ionizer for sputtered neutral mass spectrometry (SNMS), which is compact enough to be mounted in secondary ion mass spectrometry (SIMS) instruments, has been developed. The compact energy analyzer, called a modified Bessel-Box, enables energy distribution of slow charged particles with different energy resolutions to be obtained by changing the ratio of voltages applied to the analyzer. Applying this system for SNMS of Al-Mg alloy under different partial pressures of oxygen, it has been confirmed that SNMS is free from oxygen enhancement, allowing the quantification of matrix elements with considerable accuracy. It has also been revealed that the space-charge effect caused by bombarding electrons becomes fairly marked, resulting in the deformation and shift of energy distributions of the postionized particles.

  8. Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)

    SciTech Connect

    Campbell, James A.; Szecsody, Jim E.; Devary, Brooks J.; Valenzuela, Blandina R.

    2007-09-03

    Hexanitrohexaazaisowurtzitane, (C6H6N12O12, MW 438) {CL-20}, is a high-energy propellent that has been recently developed and successfully tested (Nielsen et al. 1998). CL-20 releases more energy on ignition and is more stable to accidental detonation than currently used energetic materials. It is expected to replace many of the energetic materials currently being used by the Department of Defense (DoD). The EPA method 8330 (EPA 1997) for the analysis of explosives and metabolites in soils calls for the use of UV/Vis detection. High performance liquid chromatography has been used to quantify CL-20 and precursor concentration (Bazaki et al. 1998`) at relatively high concentrations. Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal forms of CL-20 (4 isomers; Kim et al. 1998). Campbell et al. (1997) utilized particle beam mass spectrometry for the analysis of enzymatic degradation of explosives. Introduction and recent improvements of ionization techniques such as electrospray (ES) have allowed the mass spectrometer to become more widely used in liquid chromatography. Schilling(1996) also examined explosive components and metabolites using electrospray (ES) and atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). Schilling’s results showed that compared to thermospray LC/MS, APCI and ES were more sensitive than thermospray by at least an order of magnitude. 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 10 nitroso-RDX metabolites, and other munitions in ground water have been analyzed using solid phase extraction and isotope dilution liquid chromatography-APCI mass spectrometry (Cassada et al. 1999). The method detection limits indicate that nitramine and nitroaromatic compounds can be routinely determined in ground water samples using electrospray LC/MS with concentration techniques utilizing solid-phase extraction. Miller et al. (1996) studied nitrated explosives with mobile phase

  9. Optimization of Whole-Body Zebrafish Sectioning Methods for Mass Spectrometry Imaging

    EPA Science Inventory

    Mass spectrometry imaging methods and protocols have become widely adapted to a variety of tissues and species. However, the mass spectrometry imaging literature contains minimal information on whole-body cryosection preparation for the zebrafish (Danio rerio), a model organism ...

  10. "EMERGING" POLLUTANTS, MASS SPECTROMETRY, AND COMMUNICATING SCIENCE: PHARMACEUTICALS IN THE ENVIRONMENT

    EPA Science Inventory

    A foundation for Environmental Science - Mass Spectrometry: Historically fundamental to amassing our understanding of environmental processes and chemical pollution is the realm of mass spectrometry - the mainstay of analytical chemistry - the workhorse that supplies much of the...

  11. Identification of carbohydrate anomers using ion mobility-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hofmann, J.; Hahm, H. S.; Seeberger, P. H.; Pagel, K.

    2015-10-01

    Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

  12. Compound-specific chlorine isotope analysis: a comparison of gas chromatography/isotope ratio mass spectrometry and gas chromatography/quadrupole mass spectrometry methods in an interlaboratory study.

    PubMed

    Bernstein, Anat; Shouakar-Stash, Orfan; Ebert, Karin; Laskov, Christine; Hunkeler, Daniel; Jeannottat, Simon; Sakaguchi-Söder, Kaori; Laaks, Jens; Jochmann, Maik A; Cretnik, Stefan; Jager, Johannes; Haderlein, Stefan B; Schmidt, Torsten C; Aravena, Ramon; Elsner, Martin

    2011-10-15

    Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of (37)Cl/(35)Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of δ(37)Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1σ ≈ 0.1‰), to GC/qMS (1σ ≈ 0.2-0.5‰ for Agilent GC/qMS and 1σ ≈ 0.2-0.9‰ for Thermo GC/qMS). Nonetheless, δ(37)Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications. PMID:21851081

  13. Proton transfer reaction-mass spectrometry applications in medical research.

    PubMed

    Herbig, Jens; Amann, Anton

    2009-06-01

    Gathering information about a subject's physiological and pathophysiological condition from the `smell' of breath is an idea that dates back to antiquity. This intriguing concept of non-invasive diagnosis has been revitalized by `exhaled breath analysis' in recent decades. A main driving force was the development of sensitive and versatile gas-chromatographic and mass-spectrometric instruments for trace gas analysis. Ironically, only non-smelling constituents of breath, such as O(2), CO(2), H(2), and NO have so far been included in routine clinical breath analysis. The `smell' of human breath, on the other hand, arises through a combination of volatile organic compounds (VOCs) of which several hundred have been identified to date. Most of these volatiles are systemic and are released in the gas-exchange between blood and air in the alveoli. The concentration of these compounds in the alveolar breath is related to the respective concentrations in blood. Measuring VOCs in exhaled breath allows for screening of disease markers, studying the uptake and effect of medication (pharmacokinetics), or monitoring physiological processes. There is a range of requirements for instruments for the analysis of a complex matrix, such as human breath. Mass-spectrometric techniques are particularly well suited for this task since they offer the possibility of detecting a large variety of interesting compounds. A further requirement is the ability to measure accurately in the concentration range of breath VOCs, i.e. between parts-per-trillion (pptv) and parts-per-million (ppmv) range. In the mid 1990's proton transfer reaction-mass spectrometry (PTR-MS) was developed as a powerful and promising tool for the analysis of VOCs in gaseous media. Soon thereafter these instruments became commercially available to a still growing user community and have now become standard equipment in many fields including environmental research, food and flavour science, as well as life sciences. Their

  14. Application of Mass Spectrometry in the Synthesis and Characterization of Metal Nanoclusters.

    PubMed

    Lu, Yizhong; Chen, Wei

    2015-11-01

    In recent years, mass spectrometry has been widely used in the characterization of metal nanoclusters. In this Feature, we first give an introductory tutorial on mass spectrometry and then highlight the versatile applications of mass spectrometry in accurately analyzing core size, atom-level composition, charge states, etc. of metal nanoclusters and size evolution during synthesis. Finally, some perspectives on the future applications of mass spectrometry in nanocluster research are given. PMID:26086315

  15. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    PubMed Central

    Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David

    2016-01-01

    Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

  16. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses.

    PubMed

    Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David

    2016-01-01

    Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

  17. Mass Spectrometry-Based N-Glycomics of Colorectal Cancer

    PubMed Central

    Sethi, Manveen K.; Fanayan, Susan

    2015-01-01

    Colorectal cancer (CRC) is one of the most prevalent cancers worldwide. An increased molecular understanding of the CRC pathology is warranted to gain insights into the underlying molecular and cellular mechanisms of the disease. Altered protein glycosylation patterns are associated with most diseases including malignant transformation. Recent advances in mass spectrometry and bioinformatics have accelerated glycomics research and present a new paradigm for cancer biomarker discovery. Mass spectrometry (MS)-based glycoproteomics and glycomics, therefore, hold considerable promise to improve the discovery of novel biomarkers with utility in disease diagnosis and therapy. This review focuses on the emerging field of glycomics to present a comprehensive review of advances in technologies and their application in studies aimed at discovering novel glycan-based biomarkers. We will also discuss some of the challenges associated with using glycans as biomarkers. PMID:26690136

  18. Applications of liquid chromatography-mass spectrometry for food analysis.

    PubMed

    Di Stefano, Vita; Avellone, Giuseppe; Bongiorno, David; Cunsolo, Vincenzo; Muccilli, Vera; Sforza, Stefano; Dossena, Arnaldo; Drahos, László; Vékey, Károly

    2012-10-12

    HPLC-MS applications in the agrifood sector are among the fastest developing fields in science and industry. The present tutorial mini-review briefly describes this analytical methodology: HPLC, UHPLC, nano-HPLC on one hand, mass spectrometry (MS) and tandem mass spectrometry (MS/MS) on the other hand. Analytical results are grouped together based on the type of chemicals analyzed (lipids, carbohydrates, glycoproteins, vitamins, flavonoids, mycotoxins, pesticides, allergens and food additives). Results are also shown for various types of food (ham, cheese, milk, cereals, olive oil and wines). Although it is not an exhaustive list, it illustrates the main current directions of applications. Finally, one of the most important features, the characterization of food quality (including problems of authentication and adulteration) is discussed, together with a future outlook on future directions. PMID:22560344

  19. Current Status and Future Perspectives of Mass Spectrometry Imaging

    PubMed Central

    Nimesh, Surendra; Mohottalage, Susantha; Vincent, Renaud; Kumarathasan, Prem

    2013-01-01

    Mass spectrometry imaging is employed for mapping proteins, lipids and metabolites in biological tissues in a morphological context. Although initially developed as a tool for biomarker discovery by imaging the distribution of protein/peptide in tissue sections, the high sensitivity and molecular specificity of this technique have enabled its application to biomolecules, other than proteins, even in cells, latent finger prints and whole organisms. Relatively simple, with no requirement for labelling, homogenization, extraction or reconstitution, the technique has found a variety of applications in molecular biology, pathology, pharmacology and toxicology. By discriminating the spatial distribution of biomolecules in serial sections of tissues, biomarkers of lesions and the biological responses to stressors or diseases can be better understood in the context of structure and function. In this review, we have discussed the advances in the different aspects of mass spectrometry imaging processes, application towards different disciplines and relevance to the field of toxicology. PMID:23759983

  20. Plasma-based ambient ionization mass spectrometry in bioanalytical sciences.

    PubMed

    Smoluch, Marek; Mielczarek, Przemyslaw; Silberring, Jerzy

    2016-01-01

    Plasma-based ambient ionization mass spectrometry techniques are gaining growing interest due to their specific features, such as the need for little or no sample preparation, its high analysis speed, and the ambient experimental conditions. Samples can be analyzed in gas, liquid, or solid forms. These techniques allow for a wide range of applications, like warfare agent detection, chemical reaction control, mass spectrometry imaging, polymer identification, and food safety monitoring, as well as applications in biomedical science, e.g., drug and pharmaceutical analysis, medical diagnostics, biochemical analysis, etc. Until now, the main drawback of plasma-based techniques is their quantitative aspect, but a lot of efforts have been done to improve this obstacle. PMID:25988731

  1. Mass Spectrometry-Based N-Glycomics of Colorectal Cancer.

    PubMed

    Sethi, Manveen K; Fanayan, Susan

    2015-01-01

    Colorectal cancer (CRC) is one of the most prevalent cancers worldwide. An increased molecular understanding of the CRC pathology is warranted to gain insights into the underlying molecular and cellular mechanisms of the disease. Altered protein glycosylation patterns are associated with most diseases including malignant transformation. Recent advances in mass spectrometry and bioinformatics have accelerated glycomics research and present a new paradigm for cancer biomarker discovery. Mass spectrometry (MS)-based glycoproteomics and glycomics, therefore, hold considerable promise to improve the discovery of novel biomarkers with utility in disease diagnosis and therapy. This review focuses on the emerging field of glycomics to present a comprehensive review of advances in technologies and their application in studies aimed at discovering novel glycan-based biomarkers. We will also discuss some of the challenges associated with using glycans as biomarkers. PMID:26690136

  2. Analysis of tear glucose concentration with electrospray ionization mass spectrometry.

    PubMed

    Taormina, Christopher R; Baca, Justin T; Asher, Sanford A; Grabowski, Joseph J; Finegold, David N

    2007-02-01

    We have developed a mass spectrometry-based method that allows one to accurately determine the glucose concentration of tear fluid. We used a 1 microL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 muL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting nondiabetic subject to be 13 to 51 microM while the onion-induced tear glucose concentration of a different nondiabetic subject to be 211 to 256 microM. PMID:17084090

  3. Analysis of Tear Glucose Concentration with Electrospray Ionization Mass Spectrometry

    PubMed Central

    Taormina, Christopher R.; Baca, Justin T.; Finegold, David N.; Asher, Sanford A.; Grabowski, Joseph J.

    2007-01-01

    We have developed a mass spectrometry-based method which allows one to accurately determine the glucose concentration of tear fluid. We used a 1 μL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 μL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting non-diabetic subject to be 13 to 51 μM while the onion-induced tear glucose concentration of a different non-diabetic subject to be 211 to 256 μM. PMID:17084090

  4. Accelerator mass spectrometry for quantitative in vivo tracing

    SciTech Connect

    Vogel, J S

    2005-04-19

    Accelerator mass spectrometry (AMS) counts individual rare, usually radio-, isotopes such as radiocarbon at high efficiency and specificity in milligram-sized samples. AMS traces very low chemical doses ({micro}g) and radiative doses (100 Bq) of isotope labeled compounds in animal models and directly in humans for pharmaceutical, nutritional, or toxicological research. Absorption, metabolism, distribution, binding, and elimination are all quantifiable with high precision after appropriate sample definition.

  5. Characterization of Enterobacteria using MALDI-TOF mass spectrometry.

    PubMed

    Pribil, Patrick; Fenselau, Catherine

    2005-09-15

    A method is proposed for the rapid classification of Gram-negative Enterobacteria using on-slide solubilization and trypsin digestion of proteins, followed by MALDI-TOF MS analysis. Peptides were identified from tryptic digests using microsequencing by tandem mass spectrometry and database searches. Proteins from the outer membrane family (OMP) were consistently identified in the Enterobacteria Escherichia coli, Enterobacter cloacae, Erwinia herbicola, and Salmonella typhimurium. Database searches indicate that these OMP peptides observed are unique to the Enterobacteria order. PMID:16159146

  6. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  7. Proposal on dynamic correction method for resonance ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Noto, Takuma; Tomita, Hideki; Richter, Sven; Schneider, Fabian; Wendt, Klaus; Iguchi, Tetsuo; Kawarabayashi, Jun

    2013-04-01

    For high precision and accuracy in isotopic ratio measurement of transuranic elements using laser ablation assisted resonance ionization mass spectrometry, a dynamic correction method based on correlation of ion signals with energy and timing of each laser pulse was proposed. The feasibility of this dynamic correction method was investigated through the use of a programmable electronics device for fast acquisition of the energy and timing of each laser pulse.

  8. Computational and Statistical Analysis of Protein Mass Spectrometry Data

    PubMed Central

    Noble, William Stafford; MacCoss, Michael J.

    2012-01-01

    High-throughput proteomics experiments involving tandem mass spectrometry produce large volumes of complex data that require sophisticated computational analyses. As such, the field offers many challenges for computational biologists. In this article, we briefly introduce some of the core computational and statistical problems in the field and then describe a variety of outstanding problems that readers of PLoS Computational Biology might be able to help solve. PMID:22291580

  9. Quality management in clinical application of mass spectrometry measurement systems.

    PubMed

    Vogeser, Michael; Seger, Christoph

    2016-09-01

    Thanks to highly specific analyte detection and potentially complete compensation for matrix variables based on the principle of stable isotope derivative internal standardisation, mass spectrometry methods allow the development of diagnostic tests of outstanding analytical quality. However, these features per se do not guarantee reliability of tests. A wide range of factors can introduce analytical errors and inaccuracy due to the extreme complexity of the methods involved. Furthermore, it can be expected that the application patterns of MS methods in diagnostic laboratories will change substantially during the coming years - with presumably less specialised laboratories implementing mass spectrometry. Introduction of highly automated test solutions by manufacturers will require some trade-off between operation convenience, sample throughput and analytical performance. Structured and careful quality and risk management is therefore crucial to translate the analytical power of mass spectrometry into actionable and reliable results for individual patients' care and to maintain the degree of reliability that is expected from MS methods in clinical pathology. This reflection review discusses whether particular quality assurance tools have to be applied for MS-based diagnostic tests and whether these tools are different from those applied for optical- and affinity-based standard tests. Both pre-implementation strategies and surveillance of assays with assessment of metadata in routine testing are addressed. The release of the CLSI guideline C62-A in 2014 was a substantial achievement in this context because it addresses a wide spectrum of relevant issues in quality assurance of mass spectrometry-based clinical tests. However, the translation of this best practice document into individual laboratory settings is likely to be heterogeneous. PMID:27400682

  10. Charge Prediction of Lipid Fragments in Mass Spectrometry

    SciTech Connect

    Schrom, Brian T.; Kangas, Lars J.; Ginovska, Bojana; Metz, Thomas O.; Miller, John H.

    2011-12-18

    An artificial neural network is developed for predicting which fragment is charged and which fragment is neutral for lipid fragment pairs produced from a liquid chromatography tandem mass spectrometry simulation process. This charge predictor is integrated into software developed at PNNL for in silico spectra generation and identification of metabolites known as Met ISIS. To test the effect of including charge prediction in Met ISIS, 46 lipids are used which show a reduction in false positive identifications when the charge predictor is utilized.

  11. Accelerator mass spectrometry of strontium-90 for homeland security, environmental monitoring and human health

    NASA Astrophysics Data System (ADS)

    Tumey, Scott J.; Brown, Thomas A.; Hamilton, Terry E.; Hillegonds, Darren J.

    2008-05-01

    Strontium-90 is one of the most hazardous materials managed by agencies charged with protecting the public from radiation. Traditional radiometric methods have been limited by low sample throughput and slow turnaround times. Mass spectrometry offers the advantage of shorter analysis times and the ability to measure samples immediately after processing, however conventional mass spectrometric techniques are susceptible to molecular isobaric interferences that limit their overall sensitivity. In contrast, accelerator mass spectrometry is insensitive to molecular interferences and we have therefore begun developing a method for determination of 90Sr by accelerator mass spectrometry. Despite a pervasive interference from 90Zr, our initial development has yielded an instrumental background of ∼108 atoms (75 mBq) per sample. Further refinement of our system (e.g. redesign of our detector, use of alternative target materials) is expected to push the background below 106 atoms, close to the theoretical limit for AMS. Once we have refined our system and developed suitable sample preparation protocols, we will utilize our capability in applications to homeland security, environmental monitoring and human health.

  12. Accelerator mass spectrometry of Strontium-90 for homeland security, environmental monitoring, and human health

    SciTech Connect

    Tumey, S J; Brown, T A; Hamilton, T F; Hillegonds, D J

    2008-03-03

    Strontium-90 is one of the most hazardous materials managed by agencies charged with protecting the public from radiation. Traditional radiometric methods have been limited by low sample throughput and slow turnaround times. Mass spectrometry offers the advantage of shorter analysis times and the ability to measure samples immediately after processing, however conventional mass spectrometric techniques are susceptible to molecular isobaric interferences that limit their overall sensitivity. In contrast, accelerator mass spectrometry is insensitive to molecular interferences and we have therefore begun developing a method for determination of {sup 90}Sr by accelerator mass spectrometry. Despite a pervasive interference from {sup 90}Zr, our initial development has yielded an instrumental background of {approx} 10{sup 8} atoms (75 mBq) per sample. Further refinement of our system (e.g., redesign of our detector, use of alternative target materials) is expected to push the background below 10{sup 6} atoms, close to the theoretical limit for AMS. Once we have refined our system and developed suitable sample preparation protocols, we will utilize our capability in applications to homeland security, environmental monitoring, and human health.

  13. Identification of chemical warfare agents from vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator.

    PubMed

    Nagashima, Hisayuki; Kondo, Tomohide; Nagoya, Tomoki; Ikeda, Toru; Kurimata, Naoko; Unoke, Shohei; Seto, Yasuo

    2015-08-01

    A field-portable gas chromatograph-mass spectrometer (Hapsite ER system) was evaluated for the detection of chemical warfare agents (CWAs) in the vapor phase. The system consisted of Tri-Bed concentrator gas sampler (trapping time: 3s(-1)min), a nonpolar low thermal-mass capillary gas chromatography column capable of raising temperatures up to 200°C, a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump for data acquisition, and a personal computer for data analysis. Sample vapors containing as little as 22μg sarin (GB), 100μg soman (GD), 210μg tabun (GA), 55μg cyclohexylsarin (GF), 4.8μg sulfur mustard, 390μg nitrogen mustard 1, 140μg of nitrogen mustard 2, 130μg nitrogen mustard 3, 120μg of 2-chloroacetophenone and 990μg of chloropicrin per cubic meter could be confirmed after Tri-Bed micro-concentration (for 1min) and automated AMDIS search within 12min. Using manual deconvolution by background subtraction of neighboring regions on the extracted ion chromatograms, the above-mentioned CWAs could be confirmed at lower concentration levels. The memory effects were also examined and we found that blister agents showed significantly more carry-over than nerve agents. Gasoline vapor was found to interfere with the detection of GB and GD, raising the concentration limits for confirmation in the presence of gasoline by both AMDIS search and manual deconvolution; however, GA and GF were not subject to interference by gasoline. Lewisite 1, and o-chlorobenzylidene malononitrile could also be confirmed by gas chromatography, but it was hard to quantify them. Vapors of phosgene, chlorine, and cyanogen chloride could be confirmed by direct mass spectrometric detection at concentration levels higher than 2, 140, and 10mg/m(3) respectively, by bypassing the micro-concentration trap and gas chromatographic separation. PMID:26118803

  14. Fast liquid chromatography/multiple-stage mass spectrometry of coccidiostats.

    PubMed

    Martínez-Villalba, Anna; Moyano, Encarnación; Galceran, Maria T

    2009-05-01

    Drugs that are used as medicines and also as growth promoters in veterinary care are considered as emerging environmental contaminants and in recent years concern about their potential risk to ecosystems and human health has risen. In this paper we used a method based on liquid chromatography/electrospray tandem mass spectrometry to analyze eight coccidiostatic compounds: diclazuril, dinitrocarbanilide (the main metabolite of nicarbazin), robenidine, lasalocid, monensin, salinomycin, maduramicin and nasarin. Multiple-stage mass spectrometry (MSn) based on the precursor ions [M+Na]+ (polyether ionophores), [M+H]+ (robenidine) and [M-H]- (diclazuril and dinitrocarbanilide) was used to study the fragmentation of these compounds. MSn data and genealogical relationships were used to propose a tentative assignment of the different fragment ions. Loss of water, decarboxylations, ketone beta-cleavages and rearrangement of cyclic ethers and amide groups were some of the fragmentations observed for these compounds. Liquid chromatography with a sub-2 microm particle size column was coupled to tandem mass spectrometry (LC/MS/MS) allowing the separation of these compounds in less than 7 min. Method detection limits ranging from 11 to 71 ng L(-1) and run-to-run values in terms of relative standard deviation (RSD) (up to 12%) were obtained. PMID:19308967

  15. Significant advancement of mass spectrometry imaging for food chemistry.

    PubMed

    Yoshimura, Yukihiro; Goto-Inoue, Naoko; Moriyama, Tatsuya; Zaima, Nobuhiro

    2016-11-01

    Food contains various compounds that have an impact on our daily lives. Many technologies have been established to analyze these molecules of interest in foods. However, the analysis of the spatial distribution of these compounds in foods using conventional technology, such as high-performance liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry is difficult. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is considered an ideal complementary approach. MALDI-MSI is a two-dimensional MALDI-MS technology that can detect compounds in a tissue section without extraction, purification, separation, or labeling. MALDI-MSI can be used to visualize the spatial distribution of chemical compounds or biomolecules in foods. Although the methodology of MALDI-MSI in food science is not yet fully established, the versatility of MALDI-MSI is expected to open a new frontier in food science. Herein, we describe the principles and applications of MALDI-MSI in food science and related fields. PMID:27211639

  16. Characterization of individual particles in gaseous media by mass spectrometry

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.

    1990-01-01

    An introduction is given to a system for particle analysis by mass spectrometry (PAMS) which employs particle-beam techniques to measure mass spectra on a continuous real-time basis. The system is applied to particles of both organic and inorganic compounds, and the measurements give the chemical characteristics of particles in mixtures and indicate source apportionment. The PAMS system can be used for process control and studying heterogeneous/catalytic reactions in particles, and can be fitted to study the real-time attributes of PAMS.

  17. Tissue MALDI Mass Spectrometry Imaging (MALDI MSI) of Peptides.

    PubMed

    Beine, Birte; Diehl, Hanna C; Meyer, Helmut E; Henkel, Corinna

    2016-01-01

    Matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a technique to visualize molecular features of tissues based on mass detection. This chapter focuses on MALDI MSI of peptides and provides detailed operational instructions for sample preparation of cryoconserved and formalin-fixed paraffin-embedded (FFPE) tissue. Besides sample preparation we provide protocols for the MALDI measurement, tissue staining, and data analysis. On-tissue digestion and matrix application are described for two different commercially available and commonly used spraying devices: the SunCollect (SunChrom) and the ImagePrep (Bruker Daltonik GmbH). PMID:26700046

  18. Suitability of tandem-in-time mass spectrometry for polybrominated diphenylether measurement in fish and shellfish samples: comparison with high resolution mass spectrometry.

    PubMed

    Pirard, Catherine; De Pauw, Edwin; Focant, Jean-François

    2006-05-19

    The first part of the present study focused on the development of an alternative automated sample preparation method for the measurement of selected polybrominated diphenyl ethers (PBDEs) in fish and shellfish. A previously developed automated method has been further optimized and simplified to decrease blank levels and cost. Sorbent and solvent quantities have been significantly reduced without altering extract quality. The second part of the study consisted of comparing tandem-in-time quadrupole ion storage mass spectrometry (QISTMS/MS) to high resolution mass spectrometry (HRMS) for the isotope dilution (ID) measurement step after gas chromatography (GC) separation. Both mass spectrometric methods performed similarly in terms of accuracy but better precision was observed for HRMS. Although better sensitivity can be attained with the high resolution sector instrument, method limits of quantification (mLOQs) were very similar for both approaches as they were dependent on the procedural blanks levels. The mLOQ values ranged between 0.04 and 3.56 ng/g fat, depending on the congener. They allowed the unambiguous identification and quantification of all target analytes, except for BDE-183, in most considered fish extracts. An analytical procedure based on rapid automated sample preparation and QISTMS/MS appeared to be suitable for the measurement of PBDEs in fish and shellfish speciment under quality assurance/quality control (QA/QC) criteria. PMID:16564052

  19. Imaging of Cells and Tissues with Mass Spectrometry: Adding Chemical Information to Imaging

    PubMed Central

    Zimmerman, Tyler A.; Monroe, Eric B.; Tucker, Kevin R.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2009-01-01

    Techniques that map the distribution of compounds in biological tissues can be invaluable in addressing a number of critical questions in biology and medicine. One of the newest methods, mass spectrometric imaging, has enabled investigation of spatial localization for a variety of compounds ranging from atomics to proteins. The ability of mass spectrometry to detect and differentiate a large number of unlabeled compounds makes the approach amenable to the study of complex biological tissues. This chapter focuses on recent advances in the instrumentation and sample preparation protocols that make mass spectrometric imaging of biological samples possible, including strategies for both tissue and single cell imaging using the following mass spectrometric ionization methods: matrix-assisted laser desorption/ionization, secondary ion, electrospray and desorption electrospray. PMID:19118682

  20. Mass Spectrometry in Studies of Protein Thiol Chemistry and Signaling: Opportunities and Caveats

    PubMed Central

    Devarie Baez, Nelmi O.; Reisz, Julie A.; Furdui, Cristina M.

    2014-01-01

    Mass spectrometry (MS) has become a powerful and widely utilized tool in the investigation of protein thiol chemistry, biochemistry, and biology. Very early biochemical studies of metabolic enzymes have brought to light the broad spectrum of reactivity profiles that distinguish cysteine thiols with functions in catalysis and protein stability from other cysteine residues in proteins. The development of MS methods for the analysis of proteins using electrospray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI) coupled with the emergence of high-resolution mass analyzers have been instrumental in advancing studies of thiol modifications, both in single proteins and within the cellular context. This article reviews MS instrumentation and methods of analysis employed in investigations of thiols and their reactivity toward a range of small biomolecules. A selected number of studies are detailed to highlight the advantages brought about by the MS technologies along with the caveats associated with these analyses. PMID:25261734

  1. High Resolution Double-Focusing Isotope Ratio Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Radke, J.; Deerberg, M.; Hilkert, A.; Schlüter, H.-J.; Schwieters, J.

    2012-04-01

    In recent years isotope ratio mass spectrometry has extended to the capability of quantifying very small isotope signatures related with low abundances and simultaneously detecting molecular masses such as isotopomers and isotopologues containing clumped isotopes. Some of those applications are limited by molecular interferences like different gas molecules with the same nominal mass, e.g. Ar/O2, adducts of the same molecule or of different molecules, and very small isotope abundances. The Thermo Scientific MAT 253 ULTRA is the next generation of high precision gas isotope ratio mass spectrometry, which combines a 10 KV gas ionization source (Thermo Scientific MAT 253) with a double focusing multi-collector mass analyzer (Thermo Scientific Neptune) and reduces those limitations by measuring isotope ratios on a larger dynamic range with high precision. Small ion beam requirements and high sensitivity are achieved by signal-to-noise improvements through enhanced ion beam amplification in faraday cups and ion counters. Interfering backgrounds, e.g. interfering isotopologues or isobaric ions of contaminants, are dramatically decreased by a dynamic range increase combined with high evacuation leading to undisturbed ion transmission through the double-focusing analyser. Furthermore, automated gain calibration for mathematical baseline corrections, switchable detector arrays, ion source control, analyser focusing and full data export is controlled under Isodat data control. New reference/sample strategies are under investigation besides incorporation of the continuous-flow technique and its versatile inlet devices. We are presenting first results and applications of the MAT 253 Ultra.

  2. Measurement of the 135Cs half-life with accelerator mass spectrometry and inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    MacDonald, C. M.; Cornett, R. J.; Charles, C. R. J.; Zhao, X. L.; Kieser, W. E.

    2016-01-01

    The isotope 135Cs is quoted as having a half-life of 2.3 Myr. However, there are three published values ranging from 1.8 to 3 Myr. This research reviews previous measurements and reports a new measurement of the half-life using newly developed accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICPMS) techniques along with β and γ radiometric analysis. The half-life was determined to be (1.6 ±0.6 ) ×106 yr by AMS and (1.3 ±0.2 ) ×106 yr by ICPMS with 95% confidence. The two values agree with each other but differ from the accepted value by ˜40 % .

  3. Two-dimensional liquid chromatography/mass spectrometry/mass spectrometry separation of water-soluble metabolites.

    PubMed

    Fairchild, Jacob N; Horvath, Krisztian; Gooding, Jessica R; Campagna, Shawn R; Guiochon, Georges

    2010-12-24

    Off-line two-dimensional liquid chromatography with tandem mass spectrometry detection (2D-LC/MS-MS) was used to separate a set of metabolomic species. Water-soluble metabolites were extracted from Escherichia coli and Saccharomyces cerevisae cultures and were immediately analyzed using strong cation exchange (SCX)-hydrophilic interaction chromatography (HILIC). Metabolite mixtures are well-suited for multidimensional chromatography as the range of components varies widely with respect to polarity and chemical makeup. Some currently used methods employ two different separations for the detection of positively and negatively ionized metabolites by mass spectrometry. Here we developed a single set of chromatographic conditions for both ionization modes and were able to detect a total of 141 extracted metabolite species, with an overall peak capacity of ca. 2500. We show that a single two-dimensional separation method is sufficient and practical when a pair or more of unidimensional separations are used in metabolomics. PMID:21094946

  4. The use of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry to demonstrate progesterone treatment in bovines.

    PubMed

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

    2016-06-01

    Currently, no analytical method is available to demonstrate progesterone administration in biological samples collected in rearing animals, and therefore, tracking the abuse of this popular growth promoter is arduous. In this study, a method is presented to reveal progesterone (PG) treatment on the basis of carbon isotope measurement of 5β-pregnane-3α, 20α-diol (BAA-PD), a major PG metabolite excreted in bovine urine, by gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS). 5-Androstene-3β,17α-diol (AEdiol) is used as endogenous reference compound. Intermediate precisions (n=11) of 0.56‰ and 0.68‰ have been determined for AEdiol and BAA-PD, respectively. The analytical method was used for the very first time to successfully differentiate urine samples collected in treated and untreated animals. PMID:27157423

  5. Neuropeptide Signaling in Crustaceans Probed by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liang, Zhidan

    Neuropeptides are one of the most diverse classes of signaling molecules whose identities and functions are not yet fully understood. They have been implicated in the regulation of a wide range of physiological processes, including feeding-related and motivated behaviors, and also environmental adaptations. In this work, improved mass spectrometry-based analytical platforms were developed and applied to the crustacean systems to characterize signaling molecules. This dissertation begins with a review of mass spectrometry-based neuropeptide studies from both temporal- and spatial-domains. This review is then followed by several chapters detailing a few research projects related to the crustacean neuropeptidomic characterization and comparative analysis. The neuropeptidome of crayfish, Orconectes rusticus is characterized for the first time using mass spectrometry-based tools. In vivo microdialysis sampling technique offers the capability of direct sampling from extracellular space in a time-resolved manner. It is used to investigate the secreted neuropeptide and neurotransmitter content in Jonah crab, Cancer borealis, in this work. A new quantitation strategy using alternative mass spectrometry data acquisition approach is developed and applied for the first time to quantify neuropeptides. Coupling of this method with microdialysis enables the study of neuropeptide dynamics concurrent with different behaviors. Proof-of-principle experiments validating this approach have been carried out in Jonah crab, Cancer borealis to study feeding- and circadian rhythm-related neuropeptide changes using micoridialysis in a time-resolved manner. This permits a close correlation between behavioral and neurochemical changes, providing potential candidates for future validation of regulatory roles. In addition to providing spatial information, mass spectrometry imaging (MSI) technique enables the characterization of signaling molecules while preserving the temporal resolution. A

  6. Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source

    PubMed Central

    Pfeuffer, Kevin P.; Ray, Steven J.; Hieftje, Gary M.

    2014-01-01

    Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last nine years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification due to the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass-spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet. PMID:24658804

  7. Tandem mass spectrometry and ion mobility mass spectrometry for the analysis of molecular sequence and architecture of hyperbranched glycopolymers

    PubMed Central

    Liu, Xiumin; Cool, Lydia R.; Lin, Kenneth; Kasko, Andrea M.; Wesdemiotis, Chrys

    2015-01-01

    Multidimensional mass spectrometry techniques, combining matrix-assisted laser desorption/ionization (MALDI) or electrospray ionization (ESI) with tandem mass spectrometry (MS2), multistage mass spectrometry (MSn) or ion mobility mass spectrometry (IM-MS), have been employed to gain precise structural insight on the compositions, sequences and architectures of small oligomers of a hyperbranched glycopolymer, prepared by atom transfer radical copolymerization of an acrylate monomer (A) and an acrylate inimer (B), both carrying mannose ester pendants. The MS data confirmed the incorporation of multiple inimer repeat units, which ultimately lead to the hyperbranched material. The various possible structures of n-mers with the same composition were subsequently elucidated based on MS2 and MSn studies. The characteristic elimination of bromomethane molecule provided definitive information about the comonomer connectivity in the copolymeric AB2 trimer and A2B2 tetramer, identifying as present only one of the three possible trimeric isomers (viz. sequence BBA) and only two of the six possible tetrameric isomers (viz. sequences BBA2 and BABA). Complementary IM-MS studies confirmed that only one of the tetrameric structures is formed. Comparison of the experimentally determined collision cross-section of the detected isomer with those predicted by molecular simulations for the two possible sequences ascertained BBA2 as the predominant tetrameric architecture. The multidimensional MS approaches presented provide connectivity information at the atomic level without requiring high product purity (due to the dispersive nature of MS) and, hence, should be particularly useful for the microstructure characterization of novel glycopolymers and other types of complex copolymers. PMID:25519163

  8. Detection of biological particles in ambient air using bio-aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    McJimpsey, Erica L.; Steele, Paul T.; Coffee, Keith R.; Fergenson, David P.; Riot, Vincent J.; Woods, Bruce W.; Gard, Eric E.; Frank, Matthias; Tobias, Herbert J.; Lebrilla, Carlito

    2006-05-01

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  9. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    SciTech Connect

    McJimpsey, E L; Steele, P T; Coffee, K R; Fergenson, D P; Riot, V J; Woods, B W; Gard, E E; Frank, M; Tobias, H J; Lebrilla, C

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  10. Emerging mass spectrometry techniques for the direct analysis of microbial colonies

    PubMed Central

    Fang, Jinshu; Dorrestein, Pieter C.

    2014-01-01

    One of the emerging areas in microbiology is detecting specialized metabolites produced by microbial colonies and communities with mass spectrometry. In this review/perspective, we illustrate the emerging mass spectrometry methodologies that enable the interrogation of specialized metabolites directly from microbial colonies. Mass spectrometry techniques such as imaging mass spectrometry and real-time mass spectrometry allow two and three dimensional visualization of the distribution of metabolites, often with minimal sample pretreatment. The speed in which molecules are captured using these methods requires the development of new molecular visualization tools such as molecular networking. Together, these tools are beginning to provide unprecedented insight into the chemical world that microbes experience. PMID:25064218

  11. Ultrahigh-resolution fourier transform mass spectrometry of biomolecules above m/z 5 000

    NASA Astrophysics Data System (ADS)

    Li, Yunzhi; Hunter, Richard L.; McIver, Robert T., Jr.

    1996-12-01

    Ions with a mass-to-charge ratio (m/z) greater than 5 000 have been made by matrix-assisted laser desorption/ionization (MALDI) and detected at high mass resolving power by Fourier transform mass spectrometry (FTMS). The FTMS instrument used for the investigations has a MALDI source mounted outside of the magnetic field in a separate, differentially-pumped chamber. Ions were extracted from the source and transported efficiently to the FTMS analyzer cell by a r.f.-only quadrupole ion guide. To optimize the mass resolution for high mass ions, the operating parameters of the instrument were varied systematically. It was found that the parameters for formation of ions in the MALDI source, such as laser irradiance and amount of sample ablated, do not affect the mass resolution significantly. The biggest effects resulted from changing the ion detection parameters in the FTMS analyzer cell, in particular the trapping voltage, excitation r.f. level, background pressure, and number of ions stored. With optimal tuning, the external ion source FTMS method gave a mass resolving power of M/[Delta]M1/2 = 830 000 for human insulin at m/z 5 807 and 81 000 for cytochrome C at m/z 12 360.

  12. Fundamentals of Biomolecule Analysis by Electrospray Ionization Mass Spectrometry

    ERIC Educational Resources Information Center

    Weinecke, Andrea; Ryzhov, Victor

    2005-01-01

    Electrospray ionization (ESI) is a soft ionization technique that allows transfer of fragile biomolecules directly from solution into the gas phase. An instrumental analysis laboratory experiment is designed that would introduce the students to the ESI technique, major parameters of the ion trap mass spectrometers and some caveats in…

  13. Plutonium measurements by accelerator mass spectrometry at LLNL

    SciTech Connect

    McAninch, J E; Hamilton, T F; Broan, T A; Jokela, T A; Knezovich, T J; Ognibene, T J; Proctor, I D; Roberts, M L; Southon, J R; Vogel, J S; Sideras-Haddad, E

    1999-10-26

    Mass spectrometric methods provide sensitive, routine, and cost-effective analyses of long-lived radionuclides. Here the authors report on the status of work at Lawrence Livermore National Laboratory (LLNL) to develop a capability for actinide measurements by accelerator mass spectrometry (AMS) to take advantage of the high potential of AMS for rejection of interferences. This work demonstrates that the LLNL AMS spectrometer is well-suited for providing high sensitivity, robust, high throughput measurements of plutonium concentrations and isotope ratios. Present backgrounds are {approximately}2 x 10{sup 7}atoms per sample for environmental samples prepared using standard alpha spectrometry protocols. Recent measurements of {sup 239+240}Pu and {sup 241}Pu activities and {sup 240}Pu/{sup 239}Pu isotope ratios in IAEA reference materials agree well with IAEA reference values and with alpha spectrometry and recently published ICP-MS results. Ongoing upgrades of the AMS spectrometer are expected to reduce backgrounds below 1 x 10{sup 6} atoms per sample while allowing simplifications of the sample preparation chemistry. These simplifications will lead to lower per-sample costs, higher throughput, faster turn around and, ultimately, to larger and more robust data sets.

  14. Mapping protein abundance patterns in the brain using voxelation combined with liquid chromatography and mass spectrometry

    SciTech Connect

    Petyuk, Vladislav A.; Qian, Weijun; Smith, Richard D.; Smith, Desmond J.

    2010-02-01

    Voxelation creates expression atlases by high-throughput analysis of spatially registered cubes or voxels harvested from the brain. The modality independence of voxelation allows a variety of bioanalytical techniques to be used to map abundance. Protein expression patterns in the brain can be obtained using liquid chromatography (LC) combined with mass spectrometry (MS). Here we describe the methodology of voxelation as it pertains particularly to LC-MS proteomic analysis: sample preparation, instrumental set up and analysis, peptide identification and protein relative abundance quantitation. We also briefly describe some of the advantages, limitations and insights into the brain that can be obtained using combined proteomic and transcriptomic maps

  15. LESA FAIMS Mass Spectrometry for the Spatial Profiling of Proteins from Tissue.

    PubMed

    Griffiths, Rian L; Creese, Andrew J; Race, Alan M; Bunch, Josephine; Cooper, Helen J

    2016-07-01

    We have shown previously that coupling of high field asymmetric waveform ion mobility spectrometry (FAIMS), also known as differential ion mobility, with liquid extraction surface analysis (LESA) mass spectrometry of tissue results in significant improvements in the resulting protein mass spectra. Here, we demonstrate LESA FAIMS mass spectrometry imaging of proteins in sections of mouse brain and liver tissue. The results are compared with LESA mass spectrometry images obtained in the absence of FAIMS. The results show that the number of different protein species detected can be significantly increased by incorporating FAIMS into the workflow. A total of 34 proteins were detected by LESA FAIMS mass spectrometry imaging of mouse brain, of which 26 were unique to FAIMS, compared with 15 proteins (7 unique) detected by LESA mass spectrometry imaging. A number of proteins were identified including α-globin, 6.8 kDa mitochondrial proteolipid, macrophage migration inhibitory factor, ubiquitin, β-thymosin 4, and calmodulin. A total of 40 species were detected by LESA FAIMS mass spectrometry imaging of mouse liver, of which 29 were unique to FAIMS, compared with 24 proteins (13 unique) detected by LESA mass spectrometry imaging. The spatial distributions of proteins identified in both LESA mass spectrometry imaging and LESA FAIMS mass spectrometry imaging were in good agreement indicating that FAIMS is a suitable tool for inclusion in mass spectrometry imaging workflows. PMID:27228471

  16. Gas Chromatography/Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry for Fingerprinting the Macondo Oil Spill.

    PubMed

    Lobodin, Vladislav V; Maksimova, Ekaterina V; Rodgers, Ryan P

    2016-07-01

    We report the first application of a new mass spectrometry technique (gas chromatography combined to atmospheric pressure chemical ionization tandem mass spectrometry, GC/APCI-MS/MS) for fingerprinting a crude oil and environmental samples from the largest accidental marine oil spill in history (the Macondo oil spill, the Gulf of Mexico, 2010). The fingerprinting of the oil spill is based on a trace analysis of petroleum biomarkers (steranes, diasteranes, and pentacyclic triterpanes) naturally occurring in crude oil. GC/APCI enables soft ionization of petroleum compounds that form abundant molecular ions without (or little) fragmentation. The ability to operate the instrument simultaneously in several tandem mass spectrometry (MS/MS) modes (e.g., full scan, product ion scan, reaction monitoring) significantly improves structural information content and sensitivity of analysis. For fingerprinting the oil spill, we constructed diagrams and conducted correlation studies that measure the similarity between environmental samples and enable us to differentiate the Macondo oil spill from other sources. PMID:27281271

  17. Four decades of structure determination by mass spectrometry: from alkaloids to heparin.

    PubMed

    Biemann, Klaus

    2002-11-01

    The early (1950's and 1960's) use of mass spectrometry in natural products chemistry and its evolution to the present significance in biochemistry is recounted. This methodology allowed the facile and speedy determination of the structure of a number of indole alkaloids, such as sarpagine, quebrachamine, and two groups isolated from the roots of Aspidosperma quebracho blanco. At the same time, the first strategy for the sequencing of small peptides by mass spectrometry was demonstrated. It slowly advanced, over a period of two decades, to an important alternative of the ubiquitous automated Edman degradation. Further advances in methodology and instrumentation established mass spectrometry as today's indispensable tool for the characterization of proteins in biochemistry and biology. A new concept of the ionization of highly acidic compounds as the protonated complexes with basic peptides, which allows the accurate determination of the molecular weights of the former, a highly sensitive method for the sequencing of heparin fragments and related sulfated glycosaminoglycans was developed more recently. PMID:12443016

  18. Mass spectrometry of the photolysis of sulfonylurea herbicides in Prairie waters.

    PubMed

    Headley, John V; Du, Jing-Long; Peru, Kerry M; McMartin, Dena W

    2010-01-01

    This review of mass spectrometry of sulfonylurea herbicides includes a focus on studies relevant to Canadian Prairie waters. Emphasis is given to data gaps in the literature for the rates of photolysis of selected sulfonylurea herbicides in different water matrices. Specifically, results are evaluated for positive ion electrospray tandem mass spectrometry with liquid chromatography separation for the study of the photolysis of chlorsulfuron, tribenuron-methyl, thifensulfuron-methyl, metsulfuron-methyl, and ethametsulfuron-methyl. LC-MS/MS is shown to be the method of choice for the quantification of sulfonylurea herbicides with instrumental detection limits ranging from 1.3 to 7.2 pg (on-column). Tandem mass spectrometry coupled with the use of authentic standards likewise has proven to be well suited for the identification of transformation products. To date, however, the power of time-of-flight MS and ultrahigh resolution MS has not been exploited fully for the identification of unknown photolysis products. Dissipation of the herbicides under natural sunlight fit pseudo-first-order kinetics with half-life values ranging from 4.4 to 99 days. For simulated sunlight, radiation wavelengths shorter than 400 nm are required to induce significant photolytic reactions. The correlation between field dissipation studies and laboratory photolysis experiments suggests that photolysis is a major pathway for the dissipation of some sulfonylurea herbicides in natural Prairie waters. PMID:19890978

  19. Surface Ionization and Soft Landing Techniques in Mass Spectrometry

    SciTech Connect

    Futrell, Jean H.; Laskin, Julia

    2010-04-01

    The advent of soft ionization techniques, notably electrospray and laser desorption ionization methods, has extended mass spectrometric methods to large molecules and molecular complexes. This both greatly expands appli¬cations of mass spectrometry and makes the activation and dissociation of complex ions an integral part of large molecule mass spectrometry. A corollary of the much greater number of internal degrees of freedom and high density of states associated with molecular complexity is that internal energies much higher than the dissociation energies for competing fragmentation processes are required for observable fragmentation in time scales sampled by mass spectrometers. This article describes the kinetics of surface-induced dissociation (SID), a particularly efficient activation method for complex ions. Two very important characteristics of SID are very rapid, sub-picosecond activation and precise control of ion internal energy by varying ion collision energy. The nature of the surface plays an important role in SID, determining both efficiency and mechanism of ion activation. Surface composition and morphology strongly influence the relative importance of competing reactions of SID, ion capture (soft-landing), surface reaction and neutralization. The important features of SID and ion soft-landing are described briefly in this review and more fully in the recommended reading list.

  20. Study of coal structure using secondary ion mass spectrometry

    SciTech Connect

    Tingey, G.L.; Lytle, J.M.; Baer, D.R.; Thomas, M.T.

    1980-12-01

    Secondary-ion Mass Spectrometry (SIMS) is examined as a tool for studying the chemical structure of coal. SIMS has potential for analysis of coal because of the following characteristics: sensitivity to chemical structure; high sensitivity to all masses; application to solids; excellent depth resolution; and reasonable spatial resolution. SIMS spectra of solid coals show differences with respect to coal rank, the spectra of high rank coal being similar to that of graphite, and the spectra of low rank coal being similar to that of wood. Some functional group analysis is also possible using SIMS. Low rank coals show a larger peak at 15 amu indicating more methyl groups than found in the higher rank coals. Fragments with two and three carbon atoms have also been examined; much larger fragments are undoubtedly present but were not evaluated in this study. Examination of these groups, which are expected to contain valuable information on coal structure, is planned for future work. It has been observed that mineral atoms present in the coal have large secondary ion yields which complicate the interpretation of the spectra. Studies on mineral-free coals and model compounds are therefore recommended to facilitate determination of organic coal structure. In addition, mass spectrometry with much greater mass resolution will aid in distinguishing between various ion species.

  1. Intact MicroRNA Analysis Using High Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  2. Constraining Anthropogenic and Biogenic Emissions Using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Spencer, Kathleen M.

    Numerous gas-phase anthropogenic and biogenic compounds are emitted into the atmosphere. These gases undergo oxidation to form other gas-phase species and particulate matter. Whether directly or indirectly, primary pollutants, secondary gas-phase products, and particulate matter all pose health and environmental risks. In this work, ambient measurements conducted using chemical ionization mass spectrometry are used as a tool for investigating regional air quality. Ambient measurements of peroxynitric acid (HO2NO2) were conducted in Mexico City. A method of inferring the rate of ozone production, PO3, is developed based on observations of HO2NO 2, NO, and NO2. Comparison of this observationally based PO3 to a highly constrained photochemical box model indicates that regulations aimed at reducing ozone levels in Mexico City by reducing NOx concentrations may be effective at higher NO x levels than predicted using accepted photochemistry. Measurements of SO2 and particulate sulfate were conducted over the Los Angeles basin in 2008 and are compared to measurements made in 2002. A large decrease in SO2 concentration and a change in spatial distribution are observed. Nevertheless, only a modest reduction in sulfate concentration is observed at ground sites within the basin. Possible explanations for these trends are investigated. Two techniques, single and triple quadrupole chemical ionization mass spectrometry, were used to quantify ambient concentrations of biogenic oxidation products, hydroxyacetone and glycolaldehyde. The use of these techniques demonstrates the advantage of triple quadrupole mass spectrometry for separation of mass analogues, provided the collision-induced daughter ions are sufficiently distinct. Enhancement ratios of hydroxyacetone and glycolaldehyde in Californian biomass burning plumes are presented as are concentrations of these compounds at a rural ground site downwind of Sacramento.

  3. Comparison of thermal ionization mass spectrometry and Multiple Collector Inductively Coupled Plasma Mass Spectrometry for cesium isotope ratio measurements

    NASA Astrophysics Data System (ADS)

    Isnard, H.; Granet, M.; Caussignac, C.; Ducarme, E.; Nonell, A.; Tran, B.; Chartier, F.

    2009-11-01

    In the nuclear domain, precise and accurate isotopic composition determination of elements in spent nuclear fuels is mandatory to validate neutron calculation codes and for nuclear waste disposal. The present study presents the results obtained on Cs isotope ratio by mass spectrometric measurements. Natural cesium is monoisotopic ( 133Cs) whereas cesium in spent fuels has 4 isotopes ( 133Cs, 134Cs, 135Cs, and 137Cs). As no standard reference material is available to evaluate the accuracy of Cs isotopic measurements, a comparison of cesium isotopic composition in spent nuclear fuels has been performed between Thermal Ionization Mass Spectrometry (TIMS) and a new method involving Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) measurements. For TIMS measurements, isotopic fractionation has been evaluated by studying the behavior of cesium isotope ratios ( 133Cs/ 137Cs and 135Cs/ 137Cs) during the analyses. For MC-ICPMS measurements, the mass bias effects have been corrected with an external mass bias correction using elements (Eu and Sb) close to cesium masses. The results obtained by the two techniques show good agreement: relative difference on 133Cs/ 137Cs and 135Cs/ 137Cs ratios for two nuclear samples, analyzed after chemical separation, ranges from 0.2% to 0.5% depending on the choice of reference value for mass bias correction by MC-ICPMS. Finally the quantification of the 135Cs/ 238U ratio by the isotope dilution technique is presented in the case of a MOx (mixed oxide) spent fuel sample. Evaluation of the global uncertainties shows that this ratio could be defined at an uncertainty of 0.5% ( k = 2). The intercomparison between two independent mass spectrometric techniques is fundamental for the evaluation of uncertainty when no isotopic standard is available.

  4. Mass spectrometry for the determination of fission products 135Cs, 137Cs and 90Sr: A review of methodology and applications

    NASA Astrophysics Data System (ADS)

    Bu, Wenting; Zheng, Jian; Liu, Xuemei; Long, Kaiming; Hu, Sheng; Uchida, Shigeo

    2016-05-01

    The radioactive fission products 135Cs, 137Cs and 90Sr have been released into the environment by human activities such as nuclear weapon tests, nuclear fuel reprocessing and nuclear power plant accidents. Monitoring of these radionuclides is important for dose assessment. Moreover, the 135Cs/137Cs isotopic ratio can be used as an important long-term fingerprint for radioactive source identification as it varies with weapon, reactor and fuel types. In recent years, mass spectrometry has become a powerful method for the determination of 135Cs, 137Cs and 90Sr in environmental samples. Mass spectrometry is characterized by the high sensitivity and low detection limit and the relatively shorter sample preparation and analysis times compared with radiometric methods. However, the mass spectrometric determination of radiocesium and 90Sr is affected by the peak tailings of the stable nuclides 133Cs and 88Sr, respectively, and the related isobaric and polyatomic interferences. Chemical separation and optimization of the mass spectrometry instrumental setup are strongly needed prior to the mass spectrometry detection. In this paper, we have reviewed the published works about the determination of 135Cs, 137Cs and 90Sr by mass spectrometry. The mass spectrometric techniques we cover are resonance ionization mass spectrometry (RIMS), thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICP-MS). For each technique, the principles or strategies used for the analysis of these radionuclides are discussed; these included the abundance sensitivity, ways to suppress the interference signals, and the instrumental setup. In particular, the chemical procedures for eliminating the interferences are also summarized. To date, triple quadrupole ICP-MS (ICP-QQQ) showed great ability for the analysis of these radionuclides and the detection limits were as low as 0.01 pg/mL levels. Finally, some investigations on the

  5. Apparatus for studying premixed laminar flames using mass spectrometry and fiber-optic spectrometry

    NASA Astrophysics Data System (ADS)

    Olsson, Jim O.; Andersson, Lars L.; Lenner, Magnus; Simonson, Margaret

    1990-03-01

    An integrated flat-flame/ microprobe sampling quadrupole mass spectrometer system, complemented by optical spectrometry based on optical fibers, is presented. The short microprobe sampling line (total 25 cm) is directly connected to an open ion source closely flanked by two nude cryopumps (900 l/s) yielding a background pressure of 10-9 Torr and a sampling pressure of about 10-5 Torr. Due to this improved microprobe system, mass spectrometry can be used for analysis of stable species (including fuel, O2, H2O, CO2, CO, and Ar) with less disturbance of the sample than with a conventional microprobe with a back pressure of about 1 Torr. Optical spectrometry is used for the study of emission from important radical species (such as C2, CH, and OH). The system is proposed as a complement to more conventional flat-flame/MBMS systems in which the sampling cone can effect the experimental system. Details are provided concerning the configuration of the whole system ranging from gas delivery to data evaluation. Test data are presented for a 16% methanol/68% oxygen/16% argon flame studied at a pressure of 40 Torr, to elucidate the special features of this system.

  6. Accelerator mass spectrometry at the University of North Texas

    NASA Astrophysics Data System (ADS)

    Anthony, J. M.; Matteson, S.; McDaniel, F. D.; Duggan, J. L.

    1989-04-01

    An accelerator mass spectrometry system designed for analysis of electronic materials is being developed and installed on the University of North Texas 3 MV tandem accelerator (National Electrostatics Corporation 9-SDH). High-resolution magnetic (40° deflection, {M}/{ΔM ≈ 350}, maximum mass-energy product 69 MeVu) and electro static (45 ° deflection, E/ q of 4.8 MeV, {E}/{ΔE}≈ 730 ) analysis, coupled with a 1.5 m time-of-flight path and total energy detection (surface barrier detector) forms the basis of the detection system. In order to provide stable element detection capability at the parts-per-trillion level in electronic materials (Si, GaAs, HgCdTe), a custom ion source, incorporating mass analysis of the sputtering beam, ultraclean slits, low cross-contamination and UHV capability, is being constructed.

  7. Mass spectrometry technology at the Jet Propulsion Laboratory (JPL)

    NASA Technical Reports Server (NTRS)

    Giffin, C. E.

    1985-01-01

    Recent developments in the field of mass spectrometry taking place at the Caltech Jet Propulsion Laboratory are highlighted. The pertinent research and development is aimed at producing an ultrahigh sensitivity mass spectrograph for both spaceflight and terrestrial applications. The unique aspect of the JPL developed technology is an integrating focal plane ion detector that obviates the need for spectral scanning since all ions over a wide mass range are monitored simultaneously. The ion detector utilizes electro-optical technology and is therefore referred to as an Electro-Optical Ion Detector (EOID). A technical description of the JPL MS/EOID, some of the current applications, and its potential benefits for internal contamination analysis are discussed.

  8. Revealing Higher Order Protein Structure Using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chait, Brian T.; Cadene, Martine; Olinares, Paul Dominic; Rout, Michael P.; Shi, Yi

    2016-04-01

    The development of rapid, sensitive, and accurate mass spectrometric methods for measuring peptides, proteins, and even intact protein assemblies has made mass spectrometry (MS) an extraordinarily enabling tool for structural biology. Here, we provide a personal perspective of the increasingly useful role that mass spectrometric techniques are exerting during the elucidation of higher order protein structures. Areas covered in this brief perspective include MS as an enabling tool for the high resolution structural biologist, for compositional analysis of endogenous protein complexes, for stoichiometry determination, as well as for integrated approaches for the structural elucidation of protein complexes. We conclude with a vision for the future role of MS-based techniques in the development of a multi-scale molecular microscope.

  9. Revealing Higher Order Protein Structure Using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chait, Brian T.; Cadene, Martine; Olinares, Paul Dominic; Rout, Michael P.; Shi, Yi

    2016-06-01

    The development of rapid, sensitive, and accurate mass spectrometric methods for measuring peptides, proteins, and even intact protein assemblies has made mass spectrometry (MS) an extraordinarily enabling tool for structural biology. Here, we provide a personal perspective of the increasingly useful role that mass spectrometric techniques are exerting during the elucidation of higher order protein structures. Areas covered in this brief perspective include MS as an enabling tool for the high resolution structural biologist, for compositional analysis of endogenous protein complexes, for stoichiometry determination, as well as for integrated approaches for the structural elucidation of protein complexes. We conclude with a vision for the future role of MS-based techniques in the development of a multi-scale molecular microscope.

  10. Revealing Higher Order Protein Structure Using Mass Spectrometry.

    PubMed

    Chait, Brian T; Cadene, Martine; Olinares, Paul Dominic; Rout, Michael P; Shi, Yi

    2016-06-01

    The development of rapid, sensitive, and accurate mass spectrometric methods for measuring peptides, proteins, and even intact protein assemblies has made mass spectrometry (MS) an extraordinarily enabling tool for structural biology. Here, we provide a personal perspective of the increasingly useful role that mass spectrometric techniques are exerting during the elucidation of higher order protein structures. Areas covered in this brief perspective include MS as an enabling tool for the high resolution structural biologist, for compositional analysis of endogenous protein complexes, for stoichiometry determination, as well as for integrated approaches for the structural elucidation of protein complexes. We conclude with a vision for the future role of MS-based techniques in the development of a multi-scale molecular microscope. Graphical Abstract ᅟ. PMID:27080007

  11. Matrix-assisted laser desorption fourier transform mass spectrometry for biological compounds

    SciTech Connect

    Hettich, R.; Buchanan, M.

    1990-01-01

    The recent development of matrix-assisted UV laser desorption (LD) mass spectrometry has made possible the ionization and detection of extremely large molecules (with molecular weights exceeding 100,000 Daltons). This technique has generated enormous interest in the biological community for the direct examination of large peptides and oligonucleotides. Although this matrix-assisted ionization method has been developed and used almost exclusively with time-of-flight (TOF) mass spectrometers, research is currently in progress to demonstrate this technique with trapped ion mass spectrometers, such as Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The potential capabilities of FTMS for wide mass range, high resolution measurement, and ion trapping experiments suggest that this instrumental technique should be useful for the detailed structural characterization of large ions generated by the matrix-assisted technique. We have recently demonstrated that matrix-assisted ultraviolet laser desorption can be successfully used with FTMS for the ionization of small peptides. The objective of this report is to summarize the application and current limitations of matrix-assisted laser desorption FTMS for the characterization of peptides and oligonucleotides at the isomeric level. 4 refs., 3 figs., 2 tabs.

  12. BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

    SciTech Connect

    Steele, P T

    2004-07-20

    Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.

  13. Analysis of Estrogens and Androgens in Postmenopausal Serum and Plasma by Liquid Chromatography-Mass Spectrometry

    PubMed Central

    Wang, Qingqing; Bottalico, Lisa; Mesaros, Clementina; Blair, Ian A.

    2014-01-01

    Liquid chromatography-selected reaction monitoring/mass spectrometry-based methodology has evolved to the point where accurate analyses of trace levels of estrogens and androgens in postmenopausal serum and plasma can be accomplished with high precision and accuracy. A suite of derivatization procedures has been developed, which together with modern mass spectrometry instrumentation provide investigators with robust and sensitive methodology. Preionized derivatives are proving to be useful as they are not subject to suppression of the electrospray signal. Postmenopausal women with elevated plasma or serum estrogens are thought to be at increased risk for breast and endometrial cancer. Therefore, significant advances in risk assessment should be possible now that reliable methodology is available. It is also possible to conduct analyses of multiple estrogens in plasma or serum. Laboratories that are currently employing liquid chromatography/mass spectrometry methodology can now readily implement this strategy. This will help conserve important plasma and serum samples available in Biobanks, as it will be possible to conduct high sensitivity analyses using low initial sample volumes. Reported levels of both conjugated and non-conjugated estrogen metabolites are close to the limits of sensitivity of many assays to date, urging caution in the interpretation of these low values. The analysis of serum androgen precursors in postmenopausal women has not been conducted routinely in the past using liquid chromatography/mass spectrometry methodology. Integration of serum androgen levels into the panel of metabolites analyzed could provide additional information for assessing cancer risk and should be included in the future. PMID:25150018

  14. Identification of Fatty Acids, Phospholipids, and Their Oxidation Products Using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry and Electrospray Ionization Mass Spectrometry

    ERIC Educational Resources Information Center

    Harmon, Christopher W.; Mang, Stephen A.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-01-01

    Electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) have found increasing application in the analysis of biological samples. Using these techniques to solve problems in analytical chemistry should be an essential component of the training of undergraduate chemists. We…

  15. Probing Neuropeptide Signaling at the Organ and Cellular Domains via Imaging Mass Spectrometry

    PubMed Central

    Ye, Hui; Greer, Tyler; Li, Lingjun

    2012-01-01

    Imaging mass spectrometry (IMS) has evolved to be a promising technology due to its ability to detect a broad mass range of molecular species and create density maps for selected compounds. It is currently one of the most useful techniques to determine the spatial distribution of neuropeptides in cells and tissues. Although IMS is conceptually simple, sample preparation steps, mass analyzers, and software suites are just a few of the factors that contribute to the successful design of a neuropeptide IMS experiment. This review provides a brief overview of IMS sampling protocols, instrumentation, data analysis tools, technological advancements and applications to neuropeptide localization in neurons and endocrine tissues. Future perspectives in this field are also provided, concluding that neuropeptide IMS could revolutionize neuronal network and biomarker discovery studies. PMID:22465716

  16. Multi-track single- and dual-channel plastic microchips for electrospray mass spectrometry.

    PubMed

    Leuthold, Luc Alexis; Reymond, Frédéric; Rossier, Joël S; Varesio, Emmanuel; Hopfgartner, Gérard

    2010-01-01

    Disposable plastic electrospray chips are particularly attractive for the automated analysis of organic compounds and organometallic compounds. Automated multi-track chip-based infusion electrospray mass spectrometry of low molecular weight compounds using an eight-channel plastic chip is presented. For that purpose, the commercial interface of a triple quadrupole linear ion trap was modified. A dual-channel plastic microchip, where two physically separated channels arrive very close to each other at the chip tip, was used to perform lock-mass accurate mass measurements on a quadrupole-time-of-flight instrument. The same chip was used to demonstrate the formation of an organometallic complex in solution on the chip tip. Furthermore, the potential to control the flow rate of each channel individually, which opens new possibilities in the study of supramolecular complexes, is discussed. PMID:20065514

  17. The role of mass spectrometry in atomic weight determinations.

    PubMed

    De Laeter, John R

    2009-01-01

    The 1914 Nobel Prize for Chemistry was awarded to Theodore Richards, whose work provided an insight into the history of the birth and evolution of matter as embedded in the atomic weights. However, the secret to unlocking the hieroglyphics contained in the atomic weights is revealed by a study of the relative abundances of the isotopes. A consistent set of internationally accepted atomic weights has been a goal of the scientific community for over a century. Atomic weights were originally determined by chemical stoichiometry--the so-called "Harvard Method," but this methodology has now been superseded by the "physical method," in which the isotopic composition and atomic masses of the isotopes comprising an element are used to calculate the atomic weight with far greater accuracy than before. The role of mass spectrometry in atomic weight determinations was initiated by the discovery of isotopes by Thomson, and established by the pioneering work of Aston, Dempster, and Nier using sophisticated mass spectrographs. The advent of the sector field mass spectrometer in 1947, revolutionized the application of mass spectrometry for both solids and gases to other fields of science including atomic weights. Subsequently, technological advances in mass spectrometry have enabled atomic masses to be determined with an accuracy better than one part in 10(7), whilst the absolute isotopic composition of many elements has been determined to produce accurate values of their atomic weights. Conversely, those same technological developments have revealed significant variations in the isotope abundances of many elements caused by a variety of physiochemical mechanisms in natural materials. Although these variations were initially seen as an impediment to the accuracy with which atomic weights could be determined, it was quickly realized that nature had provided a new tool to investigate physiochemical and biogeochemical mechanisms in nature, which could be exploited by precise and

  18. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry.

    PubMed

    Kyle, Jennifer E; Zhang, Xing; Weitz, Karl K; Monroe, Matthew E; Ibrahim, Yehia M; Moore, Ronald J; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S; Wagoner, Jessica; Polyak, Stephen J; Metz, Thomas O; Dey, Sudhansu K; Smith, Richard D; Burnum-Johnson, Kristin E; Baker, Erin S

    2016-02-15

    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Mass spectrometry (MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids' biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are often unresolvable using present approaches. Here we show that combining liquid chromatography (LC) and structurally-based ion mobility spectrometry (IMS) measurement with MS analyses distinguishes lipid isomers and allows insight into biological and disease processes. PMID:26734689

  19. Rapid Analysis of Isobaric Exogenous Metabolites by Differential Mobility Spectrometry Mass Spectrometry

    SciTech Connect

    Parson, Whitney B; Schneider, Bradley B; Kertesz, Vilmos; Corr, Jay; Covey, Thomas R.; Van Berkel, Gary J

    2011-01-01

    The direct separation of isobaric glucuronide metabolites from propranolol dosed tissue extracts by differential mobility spectrometry mass spectrometry (DMS-MS) with the use of a polar gas-phase chemical modifier was demonstrated. The DMS gas-phase separation was able to resolve the isobaric metabolites with separation times on the order of ms instead of mins to hrs typically required when using pre-ionization chromatographic separation methods. Direct separation of isobaric metabolites from the complex tissue extract was validated using standards as well as implementing an HPLC separation prior to the DMS-MS analysis to pre-separate the species of interest. The ability to separate isobaric exogenous metabolites directly from a complex tissue extract is expected to facilitate the drug development process by increasing analytical throughput without the requirement for pre-ionization cleanup or separation strategies.

  20. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    SciTech Connect

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Stephen J.; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin S.

    2016-01-01

    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Liquid chromatography and mass spectrometry (LC-MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are unresolvable using present LC-MS approaches. Here we show that combining structurally-based ion mobility spectrometry (IMS) with LC-MS measurements distinguishes lipid isomers and allows insight into biological and disease processes.

  1. Resonance ionization mass spectrometry for isotopic abundance measurements

    NASA Technical Reports Server (NTRS)

    Miller, C. M.

    1986-01-01

    Resonance ionization mass spectrometry (RIMS) is a relatively new laser-based technique for the determination of isotopic abundances. The resonance ionization process depends upon the stepwise absorption of photons from the laser, promoting atoms of the element of interest through progressively higher electronic states until an ion is formed. Sensitivity arises from the efficiency of the resonant absorption process when coupled with the power available from commercial laser sources. Selectivity derives naturally from the distinct electronic structure of different elements. This isobaric discrimination has provided the major impetus for development of the technique. Resonance ionization mass spectrometry was used for analysis of the isotopic abundances of the rare earth lutetium. Isobaric interferences from ytterbium severely effect the ability to measure small amounts of the neutron-deficient Lu isotopes by conventional mass spectrometric techniques. Resonance ionization for lutetium is performed using a continuous-wave laser operating at 452 nm, through a sequential two-photon process, with one photon exciting the intermediate resonance and the second photon causing ionization. Ion yields for microgram-sized quantities of lutetium lie between 10(6) and 10(7) ions per second, at overall ionization efficiencies approaching 10(-4). Discrimination factors against ytterbium greater than 10(6) have been measured. Resonance ionization for technetium is also being explored, again in response to an isobaric interference, molybdenum. Because of the relatively high ionization potential for Tc, three-photon, two-color RIMS processes are being developed.

  2. Atmospheric pressure infrared MALDI imaging mass spectrometry for plant metabolomics.

    PubMed

    Li, Yue; Shrestha, Bindesh; Vertes, Akos

    2008-01-15

    The utility of atmospheric pressure infrared MALDI mass spectrometry (AP IR-MALDI) was assessed for plant metabolomics studies. Tissue sections from plant organs, including flowers, ovaries, aggregate fruits, fruits, leaves, tubers, bulbs, and seeds were studied in both positive and negative ion modes. For leaves, single laser pulses sampled the cuticle and upper epidermal cells, whereas multiple pulses were demonstrated to ablate some mesophyll layers. Tandem mass spectra were obtained with collision-activated dissociation to aid with the identification of some observed ions. In the positive mode, most ions were produced as potassium, proton, or sometimes sodium ion adducts, whereas proton loss was dominant in the negative ion mode. Over 50 small metabolites and various lipids were detected in the spectra including, for example, 7 of the 10 intermediates in the citric acid cycle. Key components of the glycolysis pathway occurring in the plant cytosol were found along with intermediates of phospholipid biosynthesis and reactants or products of amino acid, nucleotide, oligosaccharide, and flavonoid biosynthesis. AP IR-MALDI mass spectrometry was used to follow the fluid transport driven by transpiration and image the spatial distributions of several metabolites in a white lily (Lilium candidum) flower petal. PMID:18088102

  3. Accelerator mass spectrometry for measurement of long-lived radioisotopes

    SciTech Connect

    Elmore, D.; Phillips, F.M.

    1987-05-01

    Particle accelerators, such as those built for research in nuclear physics, can also be used together with magnetic and electrostatic mass analyzers to measure rare isotopes at very low abundance ratios. All molecular ions can be eliminated when accelerated to energies of millions of electron volts. Some atomic isobars can be eliminated with the use of negative ions; others can be separated at high energies by measuring their rate of energy loss in a detector. The long-lived radioisotopes /sup 10/Be, /sup 14/C, /sup 26/Al, /sup 36/Cl, and /sup 129/I can now be measured in small natural samples having isotopic abundances in the range 10/sup -12/ to 10/sup -15/ and as few as 10/sup 5/ atoms. In the past few years, research applications of accelerator mass spectrometry have been concentrated in the earth sciences (climatology, cosmochemistry, environmental chemistry, geochronology, glaciology, hydrology, igneous petrogenesis, minerals exploration, sedimentology, and volcanology), in anthropology and archaeology (radiocarbon dating), and in physics (searches for exotic particles and measurement of half-lives). In addition, accelerator mass spectrometry may become an important tool for the materials and biological sciences. 98 references, 4 figures, 2 tables.

  4. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    PubMed Central

    Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long

    2015-01-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 oC) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user–friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source. PMID:26582511

  5. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization.

    PubMed

    Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long

    2015-01-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 (o)C) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user-friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source. PMID:26582511

  6. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long

    2015-11-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 oC) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user-friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source.

  7. Laser desorption mass spectrometry for point mutation detection

    SciTech Connect

    Taranenko, N.I.; Chung, C.N.; Zhu, Y.F.

    1996-12-31

    A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

  8. Laser desorption mass spectrometry for point mutation detection

    SciTech Connect

    Taranenko, N.I.; Chung, C.N.; Zhu, Y.F.

    1996-10-01

    A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments generated by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

  9. Capillary zone electrophoresis-mass spectrometry of peptides and proteins

    SciTech Connect

    Loo, J.A.; Udseth, H.R.; Smith, R.D.

    1989-05-01

    Capillary zone electrophoresis (CZE) is attracting extensive attention as a fast, high resolution analytical and micro-preparative separations technique for systems of biological interest. In zone electrophoresis, a column is filled with a single electrolyte having a specific conductivity. The mixture of substances to be separated is applied as a narrow band to the head of a buffer filled column in a band whose width is much less than the length of the column and at a concentration too low to affect the buffer conductivity. An electric field is then applied across the length of the column and the individual substances migrate and separate according to their net electrophoretic velocities. Zone electrophoresis carried out in small diameter (<100 ..mu..m) fused silica capillaries is a relatively new approach to the high resolution separation of aqueous samples. Very small volume samples (picoliter range) with separation efficiencies on the order of 10/sup 6/ theoretical plates for amino acids have been achieved. The method can be further enhanced by the dynamic combination of detection sensitivity and selectivity offered by mass spectrometry (MS). The on-line marriage of mass spectrometry to CZE is accomplished by an atmospheric pressure electrospray ionization source interface. Our research efforts have demonstrated that proteins with MW's greater than 100 kDa can be analyzed using a conventional quadrupole mass spectrometer with an upper m/z limit of only 1700. 6 refs.

  10. Direct detection of fatty acid ethyl esters using low temperature plasma (LTP) ambient ionization mass spectrometry for rapid bacterial differentiation.

    PubMed

    Zhang, J Isabella; Costa, Anthony B; Tao, W Andy; Cooks, R Graham

    2011-08-01

    Low temperature plasma mass spectrometry (LTP-MS) was employed to detect fatty acid ethyl esters (FAEE) from bacterial samples directly. Positive ion mode FAEE mass spectrometric profiles of sixteen different bacterial samples were obtained without extraction or other sample preparation. In the range m/z 200-300, LTP mass spectra show highly reproducible and characteristic patterns. To identify the FAEE's associated with the characteristic peaks, accurate masses were recorded in the full scan mode using an LTQ/Orbitrap instrument, and tandem mass spectrometry was performed. Data were examined by principal component analysis (PCA) to determine the degree of differentiation possible amongst different bacterial species. Gram-positive and gram-negative bacteria are readily distinguished, and 11 out of 13 Salmonella strains show distinctive patterns. Growth media effects are observed but do not interfere with species recognition based on the PCA results. PMID:21706093

  11. Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting

    SciTech Connect

    J Kiselar; M Chance

    2011-12-31

    Hydroxyl radical protein footprinting coupled to mass spectrometry has been developed over the last decade and has matured to a powerful method for analyzing protein structure and dynamics. It has been successfully applied in the analysis of protein structure, protein folding, protein dynamics, and protein-protein and protein-DNA interactions. Using synchrotron radiolysis, exposure of proteins to a 'white' X-ray beam for milliseconds provides sufficient oxidative modification to surface amino acid side chains, which can be easily detected and quantified by mass spectrometry. Thus, conformational changes in proteins or protein complexes can be examined using a time-resolved approach, which would be a valuable method for the study of macromolecular dynamics. In this review, we describe a new application of hydroxyl radical protein footprinting to probe the time evolution of the calcium-dependent conformational changes of gelsolin on the millisecond timescale. The data suggest a cooperative transition as multiple sites in different molecular subdomains have similar rates of conformational change. These findings demonstrate that time-resolved protein footprinting is suitable for studies of protein dynamics that occur over periods ranging from milliseconds to seconds. In this review, we also show how the structural resolution and sensitivity of the technology can be improved as well. The hydroxyl radical varies in its reactivity to different side chains by over two orders of magnitude, thus oxidation of amino acid side chains of lower reactivity are more rarely observed in such experiments. Here we demonstrate that the selected reaction monitoring (SRM)-based method can be utilized for quantification of oxidized species, improving the signal-to-noise ratio. This expansion of the set of oxidized residues of lower reactivity will improve the overall structural resolution of the technique. This approach is also suggested as a basis for developing hypothesis

  12. Characterization of HOCl using atmospheric pressure ionization mass spectrometry

    SciTech Connect

    Caldwell, T.E.; Foster, K.L.; Benter, T.; Langer, S.; Hemminger, J.C.; Finlayson-Pitts, B.J.

    1999-10-14

    HOCl is an important intermediate in stratospheric and tropospheric chemistry. Although it can be readily measured in laboratory systems at low pressures ({le}20 Torr) using conventional electron impact ionization mass spectrometry, there is a need for a measurement technique that can operate at higher pressures, up to 1 atm in air. One such technique seeing increasing use is atmospheric pressure ionization mass spectrometry (API-MS). The authors report here studies of the API-MS of {approximately}0.5--50 ppm HOCl at a total pressure of 1 atm and room temperature. Major peaks from the ion-adducts with Cl{sup {minus}} and OCI{sup {minus}} were observed. The Br{sup {minus}} adduct of HOCl can also be generated using bromoform in the discharge region of the ion source. At the lower range of HOCl concentrations studied in air, the O{sub 2}{sup {minus}} adduct and small parent peaks assigned to HOCl{sup {minus}} were observed. The species present as minor impurities in the HOCl source (Cl{sub 2}, Cl{sub 2}O and HCl) can be readily distinguished through identification of the parent ion for Cl{sub 2}, or as their adducts with Cl{sup {minus}} and Br{sup {minus}} for Cl{sub 2}O and HCI. The identification of HOCl was confirmed using electron impact ionization time-of-flight mass spectrometry (El-MS). HOCl was quantified using EI-MS to measure the Cl{sub 2} generated when the HOCl reacted heterogeneously on a water-ice/HCl surface and independently by photolysis of the HOCl to generate atomic chlorine, which was trapped using propene and measured as chloroacetone. The implications for the use of API-MS for measuring HOCl in laboratory systems and in ambient air are discussed.

  13. Validation of New Instrumentation for Isotope Dilution Mass Spectrometric Determination of Organic Serum Analytes

    PubMed Central

    Ellerbe, P.; Phinney, C. S.; Sniegoski, L. T.; Welch, M. J.

    1999-01-01

    A major activity in the 20 year collaboration between the Analytical Chemistry Division at NIST and the College of American Pathologists (CAP) has been the development of highly accurate and precise “definitive” methods for important clinical analytes in human serum. Definitive methods for organic analytes use isotope dilution/gas chromatography/mass spectrometry and require a mass spectrometer capable of making highly precise measurements of the ratio between the ion intensities of a characteristic ion from the analyte of interest and its stable-isotope-labeled analog. Recently, the mass spectrometer used for 20 years for definitive method development and measurements was replaced with a modern instrument capable of automated operation, with accompanying gains in convenience and sample throughput. Switching to the new instrument required modifications of measurement protocols, acceptance criteria, and ratio calculations with background corrections to go along with automated instrument operation. Results demonstrated that the two instruments gave comparable results for measurements of both urea and cholesterol in samples from various serum-based Standard Reference Materials [SRMs] and College of American Pathologists materials.

  14. Using isotope dilution mass spectrometry to determine aqueous trichloroacetic acid

    SciTech Connect

    Norwood, D.L.; Christman, R.F.; Johnson, J.D.; Hass, J.R.

    1986-01-01

    The development, verification, and application of a method based on isotope-dilution gas chromatography-mass spectrometry to determine aqueous trichloroacetic acid (TCAA) at the micrograms per litre level are described. The simultaneous determination of aqueous chloroform is also demonstrated. Trichloroacetic acid is shown to be a significant by-product of the chlorination of raw waters in the laboratory and to constitute a large fraction of the total organic halide (TOX) formed. Analysis of finished-water samples indicated that TCAA, like trihalomethanes is ubiquitous. Positive correlations exist between the levels of TCAA in laboratory-chlorinated raw waters and in finished waters and measured TOX.

  15. Hydrogen exchange mass spectrometry: Are we out of the quicksand?

    PubMed Central

    Iacob, Roxana E.; Engen, John R.

    2012-01-01

    Although the use of hydrogen exchange (HX) mass spectrometry (MS) to study proteins and protein conformation is now over 20 years old, the perception lingers that it still has “issues”. Is this method, in fact, still in the quicksand with many remaining obstacles to overcome? We do not think so. This critical insight addresses the “issues” and explores several broad questions including: have the limitations of HX MS been surmounted and has HX MS achieved “indispensable” status in the pantheon of protein structural analysis tools. PMID:22476891

  16. Separation of steroid isomers by ion mobility mass spectrometry.

    PubMed

    Ahonen, Linda; Fasciotti, Maíra; Gennäs, Gustav Boije Af; Kotiaho, Tapio; Daroda, Romeu J; Eberlin, Marcos; Kostiainen, Risto

    2013-10-01

    Ion mobility mass spectrometry performed in a compact traveling wave cell (TWIM-MS) is shown to provide a reliable, fast and repeatable method to separate derivatized steroid isomers. Three steroid isomer pairs were analyzed in their native form and as their p-toluenesulfonyl isocyanate derivatives. The native steroids were separated from each other, but no separation could be attained for the isomers. The derivatized steroid isomers were, however, properly separated by TWIM-MS with peak-to-peak resolutions close to or as high as baseline resolution (Rp-p=0.77-1.08). PMID:23992881

  17. Application of accelerator mass spectrometry in aluminum metabolism studies

    NASA Astrophysics Data System (ADS)

    Meirav, O.; Sutton, R. A. L.; Fink, D.; Middleton, R.; Klein, J.; Walker, V. R.; Halabe, A.; Vetterli, D.; Johnson, R. R.

    1990-12-01

    The recent recognition that aluminum causes toxicity in uremie patients and may be associated with Alzheimer's disease has stimulated many studies of its biochemical effects. However, such studies were hampered by the lack of a suitable tracer. In a novel experiment, we have applied the new technique of accelerator mass spectrometry to investigate aluminum kinetics in rats, using as a marker the long-lived isotope 26Al. We present the first aluminum kinetic model for a biological system. The results clearly demonstrate the advantage this technique holds for isotope tracer studies in animals as well as in humans.

  18. Plasma mass spectrometry as a detector for chemical speciation studies.

    PubMed

    Tomlinson, M J; Lin, L; Caruso, J A

    1995-03-01

    Inductively coupled plasma mass spectrometry (ICP-MS), when coupled with the unique separating power of various chromatographic techniques, allows the detection of various elements at ultra-trace levels. The investigation of various toxic elements of environmental concern coupling relatively recent techniques, such as supercritical fluid chromatography (SFC) and capillary zone electrophoresis (CZE), to ICP-MS, is discussed. Comparisons have been made with detection limits obtained by using the flame ionization detector. The conventional technique of liquid chromatography for the speciation of vanadium, chromium and nickel is also discussed. PMID:7741220

  19. Mass spectrometry cancer data classification using wavelets and genetic algorithm.

    PubMed

    Nguyen, Thanh; Nahavandi, Saeid; Creighton, Douglas; Khosravi, Abbas

    2015-12-21

    This paper introduces a hybrid feature extraction method applied to mass spectrometry (MS) data for cancer classification. Haar wavelets are employed to transform MS data into orthogonal wavelet coefficients. The most prominent discriminant wavelets are then selected by genetic algorithm (GA) to form feature sets. The combination of wavelets and GA yields highly distinct feature sets that serve as inputs to classification algorithms. Experimental results show the robustness and significant dominance of the wavelet-GA against competitive methods. The proposed method therefore can be applied to cancer classification models that are useful as real clinical decision support systems for medical practitioners. PMID:26611346

  20. Biomedical Mass Spectrometry in Today's and Tomorrow's Clinical Microbiology Laboratories

    PubMed Central

    Welker, Martin; Erhard, Marcel; Chatellier, Sonia

    2012-01-01

    Clinical microbiology is a conservative laboratory exercise where base technologies introduced in the 19th century remained essentially unaltered. High-tech mass spectrometry (MS) has changed that. Within a few years following its adaptation to microbiological diagnostics, MS has been introduced, embraced, and broadly accepted by clinical microbiology laboratories throughout the world as an innovative tool for definitive bacterial species identification. Herein, we review the current state of the art with respect to this exciting new technology and discuss potential future applications. PMID:22357505