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Sample records for exchange mass spectrometry

  1. Analytical Aspects of Hydrogen Exchange Mass Spectrometry

    Science.gov (United States)

    Engen, John R.; Wales, Thomas E.

    2015-07-01

    This article reviews the analytical aspects of measuring hydrogen exchange by mass spectrometry (HX MS). We describe the nature of analytical selectivity in hydrogen exchange, then review 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 HX MS 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 can 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.

  2. Biological insights from hydrogen exchange mass spectrometry.

    Science.gov (United States)

    Jaswal, Sheila S

    2013-06-01

    Over the past two decades, hydrogen exchange mass spectrometry (HXMS) has achieved the status of a widespread and routine approach in the structural biology toolbox. The ability of hydrogen exchange to detect a range of protein dynamics coupled with the accessibility of mass spectrometry to mixtures and large complexes at low concentrations result in an unmatched tool for investigating proteins challenging to many other structural techniques. Recent advances in methodology and data analysis are helping HXMS deliver on its potential to uncover the connection between conformation, dynamics and the biological function of proteins and complexes. This review provides a brief overview of the HXMS method and focuses on four recent reports to highlight applications that monitor structure and dynamics of proteins and complexes, track protein folding, and map the thermodynamics and kinetics of protein unfolding at equilibrium. These case studies illustrate typical data, analysis and results for each application and demonstrate a range of biological systems for which the interpretation of HXMS in terms of structure and conformational parameters provides unique insights into function. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Hydrogen Exchange Mass Spectrometry: Are We Out of the Quicksand?

    Science.gov (United States)

    Iacob, Roxana E.; Engen, John R.

    2012-06-01

    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.

  4. Online deuterium hydrogen exchange and protein digestion coupled with ion mobility spectrometry and tandem mass spectrometry.

    Science.gov (United States)

    Donohoe, Gregory C; Arndt, James R; Valentine, Stephen J

    2015-05-19

    Online deuterium hydrogen exchange (DHX) and pepsin digestion (PD) is demonstrated using drift tube ion mobility spectrometry (DTIMS) coupled with linear ion trap (LTQ) mass spectrometry (MS) with electron transfer dissociation (ETD) capabilities. DHX of deuterated ubiquitin, followed by subsequent quenching and digestion, is performed within ∼60 s, yielding 100% peptide sequence coverage. The high reproducibility of the IMS separation allows spectral feature matching between two-dimensional IMS-MS datasets (undeuterated and deuterated) without the need for dataset alignment. Extracted ion drift time distributions (XIDTDs) of deuterated peptic peptides are mobility-matched to corresponding XIDTDs of undeuterated peptic peptides that were identified using collision-induced dissociation (CID). Matching XIDTDs allows a straightforward identification and deuterium retention evaluation for labeled peptides. Aside from the mobility separation, the ion trapping capabilities of the LTQ, combined with ETD, are demonstrated to provide single-residue resolution. Deuterium retention for the c- series ions across residues M(1)-L(15) and N(25)-R(42) are in good agreement with the known secondary structural elements within ubiquitin.

  5. The Area Between Exchange Curves as a Measure of Conformational Differences in Hydrogen-Deuterium Exchange Mass Spectrometry Studies

    Science.gov (United States)

    Mazur, Sharlyn J.; Weber, Daniel P.

    2017-05-01

    Hydrogen-deuterium exchange mass spectrometry (HDX-MS) provides information about protein conformational mobility under native conditions. The area between exchange curves, A bec , a functional data analysis concept, was adapted to the interpretation of HDX-MS data and provides a useful measure of exchange curve dissimilarity for tests of significance. Importantly, for most globular proteins under native conditions, A bec values provide an estimate of the log ratio of exchange-competent fractions in the two states, and thus are related to differences in the free energy of microdomain unfolding.

  6. Hydrogen-exchange mass spectrometry for the study of intrinsic disorder in proteins.

    Science.gov (United States)

    Balasubramaniam, Deepa; Komives, Elizabeth A

    2013-06-01

    Amide hydrogen/deuterium exchange detected by mass spectrometry (HXMS) is seeing wider use for the identification of intrinsically disordered parts of proteins. In this review, we discuss examples of how discovery of intrinsically disordered regions and their removal can aid in structure determination, biopharmaceutical quality control, the characterization of how post-translational modifications affect weak structuring of disordered regions, the study of coupled folding and binding, and the characterization of amyloid formation. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Structural changes of ultrasonicated bovine serum albumin revealed by hydrogen-deuterium exchange and mass spectrometry.

    Science.gov (United States)

    Zhang, Qiuting; Tu, Zongcai; Wang, Hui; Huang, Xiaoqin; Sha, Xiaomei; Xiao, Hui

    2014-11-01

    The structural changes of bovine serum albumin (BSA) under high-intensity ultrasonication were investigated by fluorescence spectroscopy and mass spectrometry. Evidence for the ultrasonication-induced conformational changes of BSA was provided by the intensity changes and maximum-wavelength shift in fluorescence spectrometry. Matrix-assisted laser desorption-ionization time-of-flight mass spectroscopy (MALDI-TOF MS) revealed the increased intensity of the peak at the charge state +5 and a newly emerged peak at charge state +6, indicating that the protein became unfolded after ultrasonication. Prevalent unfolding of BSA after ultrasonication was revealed by hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS). Increased intensity and duration of ultrasonication further promoted the unfolding of the protein. The unfolding induced by ultrasonication goes through an intermediate state similar to that induced by a low concentration of denaturant.

  8. Measuring the hydrogen/deuterium exchange of proteins at high spatial resolution by mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper Dyrberg; Zehl, Martin; Jørgensen, Thomas J D

    2014-01-01

    the sum of the exchange kinetics for the individual backbone amides. Local exchange kinetics is typically achieved by using pepsin digestion under quench conditions (i.e., under cold acidic conditions where the amide hydrogen exchange rate is slowed by many orders of magnitude). The ability to localize...... resolution of the lowest-energy structure of the native ensemble. There is a growing need for sensitive analytical tools to explore all of the significant molecular structures in the conformational landscape of proteins. Hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS) has recently emerged...... as a powerful method for characterizing protein conformational dynamics. The basis of this method is the fact that backbone amides in stable hydrogen-bonded structures (e.g., α-helices and β-sheets) are protected against exchange with the aqueous solvent. All protein structures are dynamic, however...

  9. Hydrogen/deuterium exchange mass spectrometry applied to IL-23 interaction characteristics: potential impact for therapeutics.

    Science.gov (United States)

    Iacob, Roxana E; Krystek, Stanley R; Huang, Richard Y-C; Wei, Hui; Tao, Li; Lin, Zheng; Morin, Paul E; Doyle, Michael L; Tymiak, Adrienne A; Engen, John R; Chen, Guodong

    2015-04-01

    IL-23 is an important therapeutic target for the treatment of inflammatory diseases. Adnectins are targeted protein therapeutics that are derived from domain III of human fibronectin and have a similar protein scaffold to antibodies. Adnectin 2 was found to bind to IL-23 and compete with the IL-23/IL-23R interaction, posing a potential protein therapeutic. Hydrogen/deuterium exchange mass spectrometry and computational methods were applied to probe the binding interactions between IL-23 and Adnectin 2 and to determine the correlation between the two orthogonal methods. This review summarizes the current structural knowledge about IL-23 and focuses on the applicability of hydrogen/deuterium exchange mass spectrometry to investigate the higher order structure of proteins, which plays an important role in the discovery of new and improved biotherapeutics.

  10. Probing conformational changes in rhodopsin using hydrogen-deuterium exchange coupled to mass spectrometry.

    Science.gov (United States)

    Orban, Tivadar; Tsybovsky, Yaroslav

    2015-01-01

    Hydrogen-deuterium exchange coupled to mass spectrometry is a powerful tool to evaluate changes in protein conformation between two or more states. Here, we describe a complete methodology that can be used to assess conformational changes in rhodopsin accompanying its transition from the inactive to activated state upon light exposure. This approach may be employed to investigate the structure and conformational changes of various membrane proteins.

  11. Solvent accessibility of protein surfaces by amide H/2H exchange MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Truhlar, Stephanie M E; Croy, Carrie H; Torpey, Justin W; Koeppe, Julia R; Komives, Elizabeth A

    2006-11-01

    One advantage of detecting amide H/2H exchange by mass spectrometry instead of NMR is that the more rapidly exchanging surface amides are still detectable. In this study, we present quench-flow amide H/2H exchange experiments to probe how rapidly the surfaces of two different proteins exchange. We compared the amide H/2H exchange behavior of thrombin, a globular protein, and IkappaBalpha, a nonglobular protein, to explore any differences in the determinants of amide H/2H exchange rates for each class of protein. The rates of exchange of only a few of the surface amides were as rapid as the "intrinsic" exchange rates measured for amides in unstructured peptides. Most of the surface amides exchanged at a slower rate, despite the fact that they were not seen to be hydrogen bonded to another protein group in the crystal structure. To elucidate the influence of the surface environment on amide H/2H exchange, we compared exchange data with the number of amides participating in hydrogen bonds with other protein groups and with the solvent accessible surface area. The best correlation with amide H/2H exchange was found with the total solvent accessible surface area, including side chains. In the case of the globular protein, the correlation was modest, whereas it was well correlated for the nonglobular protein. The nonglobular protein also showed a correlation between amide exchange and hydrogen bonding. These data suggest that other factors, such as complex dynamic behavior and surface burial, may alter the expected exchange rates in globular proteins more than in nonglobular proteins where all of the residues are near the surface.

  12. Analysis of urinary oligosaccharides in lysosomal storage disorders by capillary high-performance anion-exchange chromatography-mass spectrometry

    NARCIS (Netherlands)

    Bruggink, Cees; Poorthuis, Ben J. H. M.; Deelder, André M.; Wuhrer, Manfred

    2012-01-01

    Many lysosomal storage diseases are characterized by an increased urinary excretion of glycoconjugates and oligosaccharides that are characteristic for the underlying enzymatic defect. Here, we have used capillary high-performance anion-exchange chromatography (HPAEC) hyphenated to mass spectrometry

  13. Localized hydration in lyophilized myoglobin by hydrogen-deuterium exchange mass spectrometry. 2. Exchange kinetics.

    Science.gov (United States)

    Sophocleous, Andreas M; Topp, Elizabeth M

    2012-04-02

    Solid-state hydrogen-deuterium exchange with mass spectrometric analysis (ssHDX) is a promising method for characterizing proteins in amorphous solids. Though analysis of HDX kinetics is informative and well-established in solution, application of these methods to solid samples is complicated by possible heterogeneities in the solid. The studies reported here provide a detailed analysis of the kinetics of hydration and ssHDX for equine myoglobin (Mb) in solid matrices containing sucrose or mannitol. Water sorption was rapid relative to ssHDX, indicating that ssHDX kinetics was not limited by bulk water transport. Deuterium uptake in solids was well-characterized by a biexponential model; values for regression parameters provided insight into differences between the two solid matrices. Analysis of the widths of peptide mass envelopes revealed that, in solution, an apparent EX2 mechanism prevails, consistent with native conformation of the protein. In contrast, in mannitol-containing samples, a smaller non-native subpopulation exchanges by an EX1-like mechanism. Together, the results indicate that the analysis of ssHDX kinetic data and of the widths of peptide mass envelopes is useful in screening solid formulations of protein drugs for the presence of non-native species that cannot be detected by amide I FTIR.

  14. Localized Hydration in Lyophilized Myoglobin by Hydrogen-Deuterium Exchange Mass Spectrometry. 2. Exchange Kinetics

    Science.gov (United States)

    Sophocleous, Andreas M.; Topp, Elizabeth M.

    2012-01-01

    Solid-state hydrogen deuterium exchange with mass spectrometric analysis (ssHDX) is a promising method for characterizing proteins in amorphous solids. Though analysis of HDX kinetics is informative and well-established in solution, application of these methods to solid samples is complicated by possible heterogeneities in the solid. The studies reported here provide a detailed analysis of the kinetics of hydration and ssHDX for equine myoglobin (Mb) in solid matrices containing sucrose or mannitol. Water sorption was rapid relative to ssHDX, indicating that ssHDX kinetics was not limited by bulk water transport. Deuterium uptake in solids was well-characterized by a bi-exponential model; values for regression parameters provided insight into differences between the two solid matrices. Analysis of the widths of peptide mass envelopes revealed that in solution, an apparent EX2 mechanism prevails, consistent with native conformation of the protein. In contrast, in mannitol-containing samples, a smaller non-native subpopulation exchanges by an EX1-like mechanism. Together, the results indicate that the analysis of ssHDX kinetic data and the widths of peptide mass envelopes are useful in screening solid formulations of protein drugs for the presence of non-native species that cannot be detected by amide I FTIR. PMID:22352990

  15. Dynamics of urokinase receptor interaction with Peptide antagonists studied by amide hydrogen exchange and mass spectrometry

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J D; Gårdsvoll, Henrik; Danø, Keld

    2004-01-01

    on the peptide ligand. This yields bimodal isotope patterns from which dissociation rate constants can be determined. In addition, the distinct bimodal isotope distributions also allow investigation of the exchange kinetics of receptor-bound peptides providing information about the local structural motions......Using amide hydrogen exchange combined with electrospray ionization mass spectrometry, we have in this study determined the number of amide hydrogens on several peptides that become solvent-inaccessible as a result of their high-affinity interaction with the urokinase-type plasminogen activator...... hydrogens in the receptor complex. Interestingly, a naturally occurring O-linked fucose on Thr(18) confers protection of two additional amide hydrogens in GFD when it forms a complex with uPAR. Dissociation of the uPAR-peptide complexes is accompanied by a correlated exchange of nearly all amide hydrogens...

  16. Localized Hydration in Lyophilized Myoglobin by Hydrogen-Deuterium Exchange Mass Spectrometry. 1. Exchange Mapping

    Science.gov (United States)

    Sophocleous, Andreas M.; Zhang, Jun; Topp, Elizabeth M.

    2012-01-01

    The local effects of hydration on myoglobin (Mb) in solid matrices containing mannitol or sucrose (1:1 w/w, protein:additive) were mapped using hydrogen-deuterium exchange with mass spectrometric analysis (HDX-MS) at 5°C and compared to solution controls. Solid powders were exposed to D2O(g) at controlled activity (aw) followed by reconstitution and analysis of the intact protein and peptides produced by pepsin digestion. HDX varied with matrix type, aw, and position along the protein backbone. HDX was less in sucrose matrices than in mannitol matrices at all aw while the difference in solution was negligible. Differences in HDX in the two matrices were detectable despite similarities in their bulk water content. The extent of exchange in solids is proposed as a measure of the hydration of exchangeable amide groups, as well as protein conformation and dynamics; pepsin digestion allows these effects to be mapped with peptide-level resolution. PMID:22352965

  17. Electrochemical reduction of disulfide-containing proteins for hydrogen/deuterium exchange monitored by mass spectrometry

    DEFF Research Database (Denmark)

    Mysling, Simon; Salbo, Rune; Ploug, Michael

    2014-01-01

    requires a high concentration (>200 mM) of the chemical reducing agent Tris(2-carboxyethyl)phosphine (TCEP) as its reduction rate constant is decreased at low pH and temperature. Serious adverse effects on chromatographic and mass spectrometric performances have been reported when using high concentrations......Characterization of disulfide bond-containing proteins by hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS) requires reduction of the disulfide bonds under acidic and cold conditions, where the amide hydrogen exchange reaction is quenched (pH 2.5, 0 °C). The reduction typically...... some challenges in using electrochemical reduction in HDX-MS analyses and provide possible conditions to attenuate these limitations. For example, high salt concentrations hamper disulfide bond reduction, necessitating additional dilution of the sample with aqueous acidic solution at quench conditions....

  18. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained r...

  19. Probing protein interactions with hydrogen/deuterium exchange and mass spectrometry-A review

    Energy Technology Data Exchange (ETDEWEB)

    Percy, Andrew J. [Department of Chemistry, University of Calgary, Alberta (Canada); Rey, Martial; Burns, Kyle M. [Department of Biochemistry and Molecular Biology, University of Calgary, Alberta (Canada); Schriemer, David C., E-mail: dschriem@ucalgary.ca [Department of Chemistry, University of Calgary, Alberta (Canada); Department of Biochemistry and Molecular Biology, University of Calgary, Alberta (Canada)

    2012-04-06

    Highlights: Black-Right-Pointing-Pointer Protein chemistry generates mass shifts useful for structure-function studies. Black-Right-Pointing-Pointer H/DX supports a powerful mass shift method for protein interaction analysis. Black-Right-Pointing-Pointer H/DX mass shifts are useful for determining binding data (K{sub d}, off-rates). Black-Right-Pointing-Pointer Improved H/DX-MS workflows can accommodate complex protein systems. - Abstract: Assessing the functional outcome of protein interactions in structural terms is a goal of structural biology, however most techniques have a limited capacity for making structure-function determinations with both high resolution and high throughput. Mass spectrometry can be applied as a reader of protein chemistries in order to fill this void, and enable methodologies whereby protein structure-function determinations may be made on a proteome-wide level. Protein hydrogen/deuterium exchange (H/DX) offers a chemical labeling strategy suitable for tracking changes in 'dynamic topography' and thus represents a powerful means of monitoring protein structure-function relationships. This review presents the exchange method in the context of interaction analysis. Applications involving interface detection, quantitation of binding, and conformational responses to ligation are discussed, and commentary on recent analytical developments is provided.

  20. Ion Mobility Spectrometry-Mass Spectrometry Coupled with Gas-Phase Hydrogen/Deuterium Exchange for Metabolomics Analyses

    Science.gov (United States)

    Maleki, Hossein; Karanji, Ahmad K.; Majuta, Sandra; Maurer, Megan M.; Valentine, Stephen J.

    2017-09-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) in combination with gas-phase hydrogen/deuterium exchange (HDX) and collision-induced dissociation (CID) is evaluated as an analytical method for small-molecule standard and mixture characterization. Experiments show that compound ions exhibit unique HDX reactivities that can be used to distinguish different species. Additionally, it is shown that gas-phase HDX kinetics can be exploited to provide even further distinguishing capabilities by using different partial pressures of reagent gas. The relative HDX reactivity of a wide variety of molecules is discussed in light of the various molecular structures. Additionally, hydrogen accessibility scoring (HAS) and HDX kinetics modeling of candidate (in silico) ion structures is utilized to estimate the relative ion conformer populations giving rise to specific HDX behavior. These data interpretation methods are discussed with a focus on developing predictive tools for HDX behavior. Finally, an example is provided in which ion mobility information is supplemented with HDX reactivity data to aid identification efforts of compounds in a metabolite extract. [Figure not available: see fulltext.

  1. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling.

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J

    2016-03-01

    Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H](2-) ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H](3-) ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H](2-) ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H](3-) ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.

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

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Larraillet, Vincent; Schlothauer, Tilman

    2015-01-01

    in understanding and modulating the IgG-FcRn interaction to optimize antibody pharmacokinetics and ultimately improve efficacy and safety. Here we studied the interaction between a full-length human IgG1 and human FcRn via hydrogen/deuterium exchange mass spectrometry and targeted electron transfer dissociation......-type glycosylated IgG. Our results provide new molecular insight into the IgG-FcRn interaction and illustrate the capability of hydrogen/deuterium exchange mass spectrometry to advance structural proteomics by providing detailed information on the conformation and dynamics of large protein complexes in solution....

  3. Analysis of sulfonated compounds by ion-exchange high-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Socher, G; Nussbaum, R; Rissler, K; Lankmayr, E

    2001-03-30

    Ion-exchange high-performance liquid chromatography (HPIEC)-mass spectrometry (MS) was used for the analysis of different sulfonated compounds. HPIEC was performed on an aminopropyl column applying a gradient with increasing concentration of a buffer consisting of ammonium acetate-acetic acid and acetonitrile as the organic modifier. HPIEC is well suited to highly efficient separation of sulfonated compounds and furthermore, due to the volatility of ammonium acetate, the method is also appropriate for LC-MS coupling by the means of either atmospheric pressure chemical ionization or electrospray ionization. The applicability range of HPIEC-MS is demonstrated on the basis of a complex mixture of model substances consisting of sulfonated aromatics and textile dyes largely differing from each other in their structural properties.

  4. Subzero Celsius separations in three-zone temperature controlled hydrogen deuterium exchange mass spectrometry.

    Science.gov (United States)

    Wales, Thomas E; Fadgen, Keith E; Eggertson, Michael J; Engen, John R

    2017-11-10

    Hydrogen deuterium exchange mass spectrometry (HDX MS) reports on the conformational landscape of proteins by monitoring the exchange between backbone amide hydrogen atoms and deuterium in the solvent. To maintain the label for analysis, quench conditions of low temperature and pH are required during the chromatography step performed after protease digestion but before mass spectrometry. Separation at 0°C is often chosen as this is the temperature where the most deuterium can be recovered without freezing of the typical water and acetonitrile mobile phases. Several recent reports of separations at subzero Celsius emphasize the promise for retaining more deuterium and using a much longer chromatographic gradient or direct infusion time. Here we present the construction and validation of a modified Waters nanoACQUITY HDX manager with a third temperature-controlled zone for peptide separations at subzero temperatures. A new Peltier-cooled door replaces the door of a traditional main cooling chamber and the separations and trapping column are routed through the door housing. To prevent freezing, 35% methanol is introduced post online digestion. No new pumps are required and online digestion is performed as in the past. Subzero separations, using conventional HPLC column geometry of 3μ m particles in a 1×50mm column, did not result in major changes to chromatographic efficiency when lowering the temperature from 0 to -20°C. There were significant increases in deuterium recovery for both model peptides and biologically relevant protein systems. Given the higher levels of deuterium recovery, expanded gradient programs can be used to allow for higher chromatographic peak capacity and therefore the analysis of larger and more complex proteins and systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Platform Dependencies in Bottom-up Hydrogen/Deuterium Exchange Mass Spectrometry*

    Science.gov (United States)

    Burns, Kyle M.; Rey, Martial; Baker, Charles A. H.; Schriemer, David C.

    2013-01-01

    Hydrogen-deuterium exchange mass spectrometry is an important method for protein structure-function analysis. The bottom-up approach uses protein digestion to localize deuteration to higher resolution, and the essential measurement involves centroid mass determinations on a very large set of peptides. In the course of evaluating systems for various projects, we established two (HDX-MS) platforms that consisted of a FT-MS and a high-resolution QTOF mass spectrometer, each with matched front-end fluidic systems. Digests of proteins spanning a 20–110 kDa range were deuterated to equilibrium, and figures-of-merit for a typical bottom-up (HDX-MS) experiment were compared for each platform. The Orbitrap Velos identified 64% more peptides than the 5600 QTOF, with a 42% overlap between the two systems, independent of protein size. Precision in deuterium measurements using the Orbitrap marginally exceeded that of the QTOF, depending on the Orbitrap resolution setting. However, the unique nature of FT-MS data generates situations where deuteration measurements can be inaccurate, because of destructive interference arising from mismatches in elemental mass defects. This is shown through the analysis of the peptides common to both platforms, where deuteration values can be as low as 35% of the expected values, depending on FT-MS resolution, peptide length and charge state. These findings are supported by simulations of Orbitrap transients, and highlight that caution should be exercised in deriving centroid mass values from FT transients that do not support baseline separation of the full isotopic composition. PMID:23197788

  6. Quantifying Protection in Disordered Proteins Using Millisecond Hydrogen Exchange-Mass Spectrometry and Peptic Reference Peptides.

    Science.gov (United States)

    Al-Naqshabandi, Mohammed A; Weis, David D

    2017-08-08

    The extent and location of transient structure in intrinsically disordered proteins (IDPs) provide valuable insights into their conformational ensembles and can lead to a better understanding of coupled binding and folding. Millisecond amide hydrogen exchange (HX) can provide such information, but it is difficult to quantify the degree of transient structuring. One reason is that transiently disordered proteins undergo HX at rates only slightly slower than the rate of amide HX by an unstructured random coil, the chemical HX rate. In this work, we evaluate several different methods of obtaining an accurate model for the chemical HX rate suitable for millisecond hydrogen exchange mass spectrometry (HX-MS) analysis of disordered proteins: (1) calculations using the method of Englander [Bai, Y., et al. (1993) Proteins 17, 75-86], (2) measurement of HX in the presence of 6 M urea or 3 M guanidinium chloride, and (3) measurement of HX by peptide fragments derived directly from the proteins of interest. First, using unstructured model peptides and disordered domains of the activator for thyroid and retinoid receptors and the CREB binding protein as the model IDPs, we show that the Englander method has slight inaccuracies that lead to underestimation of the chemical exchange rate. Second, HX-MS measurements of model peptides show that HX rates are changed dramatically by high concentrations of the denaturant. Third, we find that measurements of HX by reference peptides from the proteins of interest provide the most accurate approach for quantifying the extent of transient structure in disordered proteins by millisecond HX-MS.

  7. Understanding Curli Amyloid-Protein Aggregation by Hydrogen-Deuterium Exchange and Mass Spectrometry.

    Science.gov (United States)

    Wang, Hanliu; Shu, Qin; Rempel, Don L; Frieden, Carl; Gross, Michael L

    2017-09-01

    Bacteria within Curli biofilms are protected from environmental pressures (e.g., disinfectants, antibiotics), and this is responsible for intractable infections. Understanding aggregation of the major protein component of Curli, CsgA, may uncover disease-associated amyloidogenesis mechanisms. Here, we report the application of pulsed hydrogen-deuterium exchange and mass spectrometry (HDX-MS) to study CsgA aggregation, thereby obtaining region-specific information. By following time-dependent peptide signal depletion, presumably a result of insoluble fibril formation, we acquired sigmoidal profiles that are specific for regions (region-specific) of the protein. These signal-depletion profiles not only provide an alternative aggregation measurement, but also give insight on soluble species in the aggregation. The HDX data present as bimodal isotopic distributions, one representing a highly disordered species whereas the other a well-structured one. Although the extents of deuterium uptake of the two species remain the same with time, the relative abundance of the lower mass, less-exchanged species increases in a region-specific manner. The same region-specific aggregation properties also pertain to different aggregation conditions. Although CsgA is an intrinsically disordered protein, within the fibril it is thought to consist of five imperfect β-strand repeating units (labeled R1-R5). We found that the exterior repeating units R1 and R5 have higher aggregation propensities than do the interior units R2, R3, and R4. We also employed TEM to obtain complementary information of the well-structured species. The results provide insight on aggregation and a new approach for further application of HDX-MS to unravel aggregation mechanisms of amyloid proteins.

  8. Probing Conformational Dynamics of Tau Protein by Hydrogen/Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Huang, Richard Y.-C.; Iacob, Roxana E.; Sankaranarayanan, Sethu; Yang, Ling; Ahlijanian, Michael; Tao, Li; Tymiak, Adrienne A.; Chen, Guodong

    2017-10-01

    Fibrillization of the microtubule-associated protein tau has been recognized as one of the signature pathologies of the nervous system in Alzheimer's disease, progressive supranuclear palsy, and other tauopathies. The conformational transition of tau in the fibrillization process, tau monomer to soluble aggregates to fibrils in particular, remains unclear. Here we report on the use of hydrogen/deuterium exchange mass spectrometry (HDX-MS) in combination with other biochemical approaches, including Thioflavin S fluorescence measurements, enzyme-linked immunosorbent assay (ELISA), and Western blotting to understand the heparin-induced tau's fibrillization. HDX-MS studies including anti-tau antibody epitope mapping experiments provided molecular level details of the full-length tau's conformational dynamics and its regional solvent accessibility upon soluble aggregates formation. The results demonstrate that R3 region in the full-length tau's microtubule binding repeat region (MTBR) is stabilized in the aggregation process, leaving both N and C terminal regions to be solvent exposed in the soluble aggregates and fibrils. The findings also illustrate the practical utility of orthogonal analytical methodologies for the characterization of protein higher order structure. [Figure not available: see fulltext.

  9. Structural Insights of Glucan Phosphatase Dynamics using Amide Hydrogen/Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Hsu, Simon; Kim, Youngjun; Li, Sheng; Durrant, Eric S.; Pace, Rachel M.; Woods, Virgil L.; Gentry, Matthew S.

    2009-01-01

    Laforin and Starch Excess 4 (SEX4) are founding members of a class of phosphatases that dephosphorylate phosphoglucans. Each protein contains a carbohydrate binding module (CBM) and a dual specificity phosphatase (DSP) domain. The gene encoding laforin is mutated in a fatal neurodegenerative disease called Lafora disease (LD). In the absence of laforin function, insoluble glucans accumulate that are hyperphosphorylated and exhibit sparse branching. It is hypothesized that these accumulations trigger the neurodegeneration and premature death of LD patients. We recently demonstrated that laforin removes phosphate from phosphoglucans and hypothesized that this function inhibits insoluble glucan accumulation. Loss of SEX4 function in plants yields a similar cellular phenotype; cells accumulate an excess amount of insoluble, hyperphosphorylated glucans. While multiple groups have shown that these phosphatases dephosphorylate phosphoglucans, there is no structure of a glucan phosphatase and little is known about the mechanism whereby they perform this action. We utilized hydrogen-deuterium exchange mass spectrometry (DXMS) and structural modeling to probe the conformational and structural dynamics of the glucan phosphatase SEX4. We found that the enzyme does not undergo a global conformational change upon glucan binding, but instead undergoes minimal rearrangement upon binding. The CBM undergoes increased protection from deuteration when bound to glucans, confirming its role in glucan binding. More interestingly, we identified structural components of the DSP that also undergo increased protection from deuteration upon glucan addition. To determine the position of these regions, we generated a homology model of the SEX4 DSP. The homology model shows that all of these regions are adjacent the DSP active site. Therefore, our results suggest that these regions of the DSP participate in presenting the phosphoglucan to the active site and provide the first structural analysis

  10. Mass Spectrometry of Halopyrazolium Salts

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Pande, U. C.

    1983-01-01

    Eleven halogen substituted 1-methyl-2-phenylpyrazolium bromides or chlorides were investigated by field desorption, field ionization, and electron impact mass spectrometry. Dealkylation was found to be the predominant thermal decomposition. An exchange between covalent and ionic halogen prior...

  11. Characterization of phosphoantigens by high-performance anion-exchange chromatography-electrospray ionization ion trap mass spectrometry and nanoelectrospray ionization ion trap mass spectrometry.

    Science.gov (United States)

    Pont, F; Luciani, B; Belmant, C; Fournié, J J

    2001-08-01

    New phosphorylated microbial metabolites referred to as phosphoantigens activate immune responses in humans. Although these molecules have leading applications in medical research, no direct method allows their rapid and unambiguous structural identification. Here, we interfaced online HPAEC (high performance anion-exchange chromatography) with ESI-ITMS (electrospray ionization ion trap mass spectrometry) to identify such pyrophosphorylated molecules. A self-regenerating anion suppressor located upstream of electrospray ionization enabled the simultaneous detection of pyrophosphoester by conductimetry, UV and MS. By HPAEC-ITMS and HPAEC-ITMS2, a single run permitted characterization of reference phosphoantigens and of related structures. Although all compounds were resolved by HPAEC, MS enabled their detection and identification by [M-H]- and fragment ions. Isobaric phosphoantigen analogues were also separated by HPAEC and distinguished by MS2. The relevance of this device was demonstrated for phosphoantigens analysis in human urine and plasma. Furthermore, identification of natural phosphoantigens by automatically generated 2D mass spectra from nano-ESI-ITMS is presented. This last technique permits the simultaneous performance of molecular screening of natural phosphoantigen extracts and their identification.

  12. Polar Aprotic Modifiers for Chromatographic Separation and Back-Exchange Reduction for Protein Hydrogen/Deuterium Exchange Monitored by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Valeja, Santosh G.; Emmett, Mark R.; Marshall, Alan G.

    2013-01-01

    Hydrogen/deuterium exchange monitored by mass spectrometry is an important non-perturbing tool to study protein structure and protein–protein interactions. However, water in the reversed-phase liquid chromatography mobile phase leads to back-exchange of D for H during chromatographic separation of proteolytic peptides following H/D exchange, resulting in incorrect identification of fast-exchanging hydrogens as unexchanged hydrogens. Previously, fast high-performance liquid chromatography (HPLC) and supercritical fluid chromatography have been shown to decrease back-exchange. Here, we show that replacement of up to 40% of the water in the LC mobile phase by the modifiers, dimethylformamide (DMF) and N-methylpyrrolidone (NMP) (i.e., polar organic modifiers that lack rapid exchanging hydrogens), significantly reduces back-exchange. On-line LC micro-ESI FT-ICR MS resolves overlapped proteolytic peptide isotopic distributions, allowing for quantitative determination of the extent of back-exchange. The DMF modified solvent composition also improves chromatographic separation while reducing back-exchange relative to conventional solvent. PMID:22298288

  13. Characterizing the dynamics of alpha-synuclein oligomers using hydrogen/deuterium exchange monitored by mass spectrometry

    DEFF Research Database (Denmark)

    Mysling, Simon; Betzer, Cristine; Jensen, Poul H

    2013-01-01

    SN (residues 94-140) underwent isotopic exchange very rapidly, demonstrating a highly dynamic region in the oligomeric state. Three regions (residues 4-17, 39-54, and 70-89) were strongly protected against isotopic exchange in the oligomers, indicating the presence of a stable hydrogen-bonded or solvent...... hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS), we have analyzed the structural dynamics of soluble αSN oligomers. The analyzed oligomers were metastable, slowly dissociating to monomers over a period of 21 days, after excess monomer had been removed. The C-terminal region of α...... analyses performed on αSN fibrils and indicated a possible zipperlike maturation mechanism for αSN aggregates. We find the protected N-terminus (residues 4-17) to be of particular interest, as this region has previously been observed to be highly dynamic for both monomeric and fibrillar αSN. This region...

  14. Mapping unstructured regions and synergistic folding in intrinsically disordered proteins with amide H/D exchange mass spectrometry.

    Science.gov (United States)

    Keppel, Theodore R; Howard, Brent A; Weis, David D

    2011-10-11

    Mapping the structured and disordered regions and identifying disorder-to-order transitions are essential to understanding intrinsically disordered proteins (IDPs). One technique that can provide such information is H/D exchange coupled with mass spectrometry (H/D-MS). To explore the feasibility of H/D-MS for mapping disordered and ordered regions in IDPs, we undertook a systematic evaluation of an unstructured protein, a molten globular protein, and the well-folded complex of the two proteins. Most segments of the unstructured protein, ACTR (activator of thyroid and retinoid receptors, NCOA3_HUMAN, residues 1018-1088), exchange at rates consistent with its assignment as an unstructured protein, but there is slight protection in regions that become helical in the ACTR-CBP complex. The molten globular protein, CBP (the nuclear coactivator binding domain of the CREB binding protein, CBP_MOUSE, residues 2059-2117), is moderately protected from exchange, and the protection is nearly uniform across the length of the protein. The uniformity arises because of rapid interconversion between an ensemble of folded conformers and an ensemble of unstructured conformers. Rapid interconversion causes the H/D exchange kinetics to be dominated by exchange by molecules in unstructured conformations. For the folded ACTR-CBP complex, the exchange data provide a qualitatively accurate description of the complex. Our results provide a useful framework to use in the interpretation of H/D-MS data of intrinsically disordered proteins.

  15. Hydrogen/Deuterium Exchange Mass Spectrometry for Probing Higher Order Structure of Protein Therapeutics: Methodology and Applications

    Science.gov (United States)

    Wei, Hui; Mo, Jingjie; Tao, Li; Russell, Reb J.; Tymiak, Adrienne A.; Chen, Guodong; Iacob, Roxana E.; Engen, John R.

    2014-01-01

    The higher order structure of protein therapeutics can be interrogated with hydrogen/deuterium exchange mass spectrometry (HDX-MS). HDX-MS is now a widely used tool in the structural characterization of protein therapeutics. In this article, HDX-MS based workflows designed for both protein therapeutic discovery and development processes are presented, focusing on the specific applications of epitope mapping for protein/drug interactions and biopharmaceutical comparability studies. Future trends in the application of HDX-MS to protein therapeutics characterization are also described. PMID:23928097

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  18. Hydrogen Exchange Mass Spectrometry of Related Proteins with Divergent Sequences: A Comparative Study of HIV-1 Nef Allelic Variants

    Science.gov (United States)

    Wales, Thomas E.; Poe, Jerrod A.; Emert-Sedlak, Lori; Morgan, Christopher R.; Smithgall, Thomas E.; Engen, John R.

    2016-06-01

    Hydrogen exchange mass spectrometry can be used to compare the conformation and dynamics of proteins that are similar in tertiary structure. If relative deuterium levels are measured, differences in sequence, deuterium forward- and back-exchange, peptide retention time, and protease digestion patterns all complicate the data analysis. We illustrate what can be learned from such data sets by analyzing five variants (Consensus G2E, SF2, NL4-3, ELI, and LTNP4) of the HIV-1 Nef protein, both alone and when bound to the human Hck SH3 domain. Regions with similar sequence could be compared between variants. Although much of the hydrogen exchange features were preserved across the five proteins, the kinetics of Nef binding to Hck SH3 were not the same. These observations may be related to biological function, particularly for ELI Nef where we also observed an impaired ability to downregulate CD4 surface presentation. The data illustrate some of the caveats that must be considered for comparison experiments and provide a framework for investigations of other protein relatives, families, and superfamilies with HX MS.

  19. The origins of enhanced activity in factor VIIa analogs and the interplay between key allosteric sites revealed by hydrogen exchange mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper D; Andersen, Mette D; Olsen, Ole H

    2008-01-01

    Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry to invest......Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry...

  20. Characterizing rapid, activity-linked conformational transitions in proteins via sub-second hydrogen deuterium exchange mass spectrometry.

    Science.gov (United States)

    Resetca, Diana; Wilson, Derek J

    2013-11-01

    This review outlines the application of time-resolved electrospray ionization mass spectrometry (TRESI-MS) and hydrogen-deuterium exchange (HDX) to study rapid, activity-linked conformational transitions in proteins. The method is implemented on a microfluidic chip which incorporates all sample-handling steps required for a 'bottom-up' HDX workflow: a capillary mixer for sub-second HDX labeling, a static mixer for HDX quenching, a microreactor for rapid protein digestion, and on-chip electrospray. By combining short HDX labeling pulses with rapid digestion, this approach provides a detailed characterization of the structural transitions that occur during protein folding, ligand binding, post-translational modification and catalytic turnover in enzymes. This broad spectrum of applications in areas largely inaccessible to conventional techniques means that microfluidics-enabled TRESI-MS/HDX is a unique and powerful approach for investigating the dynamic basis of protein function. © 2013 FEBS.

  1. Conformational Analysis of Proteins in Highly Concentrated Solutions by Dialysis-Coupled Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Houde, Damian; Esmail Nazari, Zeinab; Bou-Assaf, George M

    2016-01-01

    When highly concentrated, an antibody solution can exhibit unusual behaviors, which can lead to unwanted properties, such as increased levels of protein aggregation and unusually high viscosity. Molecular modeling, along with many indirect biophysical measurements, has suggested that the cause...... for these phenomena can be due to short range electrostatic and/or hydrophobic protein-protein interactions. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a useful tool for investigating protein conformation, dynamics, and interactions. However, "traditional" continuous dilution labeling HDX......-MS experiments have limited utility for the direct analysis of solutions with high concentrations of protein. Here, we present a dialysis-based HDX-MS (di-HDX-MS) method as an alternative HDX-MS labeling format, which takes advantage of passive dialysis rather than the classic dilution workflow. We applied...

  2. KRAS G12C Drug Development: Discrimination between Switch II Pocket Configurations Using Hydrogen/Deuterium-Exchange Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jia; Harrison, Rane A.; Li, Lianbo; Zeng, Mei; Gondi, Sudershan; Scott, David; Gray, Nathanael S.; Engen, John R.; Westover, Kenneth D. (NEU); (DFCI); (UTSMC); (Harvard-Med)

    2017-09-01

    KRAS G12C, the most common RAS mutation found in non-small-cell lung cancer, has been the subject of multiple recent covalent small-molecule inhibitor campaigns including efforts directed at the guanine nucleotide pocket and separate work focused on an inducible pocket adjacent to the switch motifs. Multiple conformations of switch II have been observed, suggesting that switch II pocket (SIIP) binders may be capable of engaging a range of KRAS conformations. Here we report the use of hydrogen/deuterium-exchange mass spectrometry (HDX MS) to discriminate between conformations of switch II induced by two chemical classes of SIIP binders. We investigated the structural basis for differences in HDX MS using X-ray crystallography and discovered a new SIIP configuration in response to binding of a quinazoline chemotype. These results have implications for structure-guided drug design targeting the RAS SIIP.

  3. Solution-phase deuterium/hydrogen exchange at a specific residue using nozzle-skimmer and electron capture dissociation mass spectrometry.

    Science.gov (United States)

    Hagman, Charlotte; Tsybin, Yury O; Håkansson, Per

    2006-01-01

    Information about protein conformation can be obtained with hydrogen/deuterium exchange (HDX) mass spectrometry. The isotopic solution-phase exchange of specific amide hydrogen atoms can be followed using low-vacuum nozzle-skimmer collision-induced dissociation (CID). In this study, the nozzle-skimmer technique was complemented by electron capture dissociation (ECD) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). The solution-phase exchange at a specific residue is monitored by comparing isotopic distributions of two consecutive b- or c-type ions. While nozzle-skimmer fragmentation takes place in the low-vacuum region of the mass spectrometer, ECD occurs at ultra-high vacuum within the mass analyzer cell of the FTICR mass spectrometer. The dissociations take place at 10(-4) and 10(-9) mbar, respectively. Low-vacuum nozzle-skimmer fragmentation can result in intramolecular exchange between product ions and solvent molecules in the gas phase. Consequently, the solution-phase information about protein or peptide conformation is lost. It was not possible to monitor isotopic solution-phase exchange at the eighth residue in substance P, (Phe)8, with nozzle-skimmer CID. By using the in-cell ECD fragmentation method, the solution-phase exchange at the (Phe)8 residue was preserved during mass spectrometric analysis. This result shows the complementary aspects of applying fragmentation at low and at high vacuum, when studying isotopic exchange in solution at specific residues using FTICRMS. Copyright 2006 John Wiley & Sons, Ltd.

  4. Effects of sucrose and benzyl alcohol on GCSF conformational dynamics revealed by hydrogen deuterium exchange mass spectrometry.

    Science.gov (United States)

    Zhang, Jun; Banks, Douglas D; He, Feng; Treuheit, Michael J; Becker, Gerald W

    2015-05-01

    Protein stability, one of the major concerns for therapeutic protein development, can be optimized during process development by evaluating multiple formulation conditions. This can be a costly and lengthy procedure where different excipients and storage conditions are tested for their impact on protein stability. A better understanding of the effects of different formulation conditions at the molecular level will provide information on the local interactions within the protein leading to a more rational design of stable and efficacious formulations. In this study, we examined the roles of the excipients, sucrose and benzyl alcohol, on the conformational dynamics of recombinant human granulocyte colony stimulating factor using hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS). Under physiological pH and temperature, sucrose globally protects the whole molecule from deuterium uptake, whereas benzyl alcohol induces increased deuterium uptake of the regions within the α-helical bundle, with even larger extent. The HDX experiments described were incorporated a set of internal peptides (Zhang et al., 2012. Anal Chem 84:4942-4949) to monitor the differences in intrinsic exchange rates in different formulations. In addition, we discussed the feasibility of implementing HDX-MS with these peptide probes in protein formulation development. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  5. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Song, Hongjian; Olsen, Ole H; Persson, Egon

    2014-01-01

    enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form...

  6. Cobalt speciation study in the cobalt-cysteine system by electrospray ionization mass spectrometry and anion-exchange chromatography inductively coupled plasma atomic emission spectrometry.

    Science.gov (United States)

    Bresson, Carole; Colin, Christèle; Chartier, Frédéric; Moulin, Christophe

    2005-05-01

    This paper describes the ability of the combination of electrospray ionization mass spectrometry (ESI-MS) and anion-exchange chromatography coupled with inductively coupled plasma atomic emission spectrometry (AEC-ICP-AES) for cobalt speciation study in the binary cobalt-cysteine system. ESI-MS, allowing the identification and the characterization of the analytes, is used as a technique complementary to AEC-ICP-AES, providing elemental information on the separated species. The methods have been developed through the study of samples containing Co2+ and 1-fold to 5-fold molar ratios of cysteine over a pH range 2.5 to 11. In each case, cobalt-cysteine complexes were characterized by ESI-MS in negative ion mode. AEC-ICP-AES allowed further separation and detection of the cobalt species previously characterized. The strong influence of pH and ligand-to-metal ratios on the nature and stoichiometry of the species is demonstrated. For the first time, a direct experimental speciation diagram of cobalt species has been established owing to these analytical techniques. This work is a promising basis for the speciation analysis of cobalt, since a good knowledge of cobalt speciation is of prime importance to better understanding its fate in biological and environmental media.

  7. Application of amide proton exchange mass spectrometry for the study of protein-protein interactions.

    Science.gov (United States)

    Mandell, Jeffrey G; Baerga-Ortiz, Abel; Croy, Carrie H; Falick, Arnold M; Komives, Elizabeth A

    2005-06-01

    This protocol describes amide proton exchange experiments that probe for changes in solvent accessibility at protein-protein interfaces. The simplest version of the protocol, termed the "on-exchange" experiment, detects protein-protein interfaces by taking advantage of the fact that solvent deuterium oxide (D2O) molecules are excluded from the surface of a protein to which another protein is bound. A more complete version of the experiment can also be performed in which the rate of surface deuteration is initially measured separately for each of the proteins involved in the interaction, after which the deuterated proteins are allowed to complex and the rate of "off-exchange" (i.e., replacement of surface deuterons by protons from solvent H2O molecules) at the resulting protein-protein interface is measured. This version of the experiment yields additional kinetic information that can help to define the solvent-inaccessible "core" of the interface.

  8. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake.

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis.

  9. Molecular Imaging Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kovac, S.

    2009-05-01

    Full Text Available Molecular imaging mass spectrometry (IMS is a recently developed method for direct determination of spatial distribution of biopolymers, preferably proteins on cell surface and tissues. Imaging mass spectrometry data are mainly based on Matrix-Assisted Laser Desorption/Ionization- Time of Flight (MALDI TOF. The MALDI TOF based imaging mass spectrometry was applied for determination of changes in kidney tissue of sensitive mice after poisoning with aristolochic acid I. The second application presented here were changes in the gastric tissue in mice after infection with Helicobacter pylori, as a model of gastric cancer in humans caused by this pathogen microorganism. Molecular imaging mass spectrometry can be applied in medicine, mostly for identification of candidate biomarkers for malignant and non-malignant diseases. Furthermore, imaging MS has almost unlimited capacity in agriculture, food technology and biotechnology, e. g. for monitoring, process development and quality control of manufactured tissue of animal, plant and microbial origin.

  10. Fourier Transform Mass Spectrometry.

    Science.gov (United States)

    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)

  11. Characterization of Stress-Exposed Granulocyte Colony Stimulating Factor Using ELISA and Hydrogen/Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Tsuchida, Daisuke; Yamazaki, Katsuyoshi; Akashi, Satoko

    2014-10-01

    Information on the higher-order structure is important in the development of biopharmaceutical drugs. Recently, hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS) has been widely used as a tool to evaluate protein conformation, and unique automated systems for HDX-MS are now commercially available. To investigate the potential of this technique for the prediction of the activity of biopharmaceuticals, granulocyte colony stimulating factor (G-CSF), which had been subjected to three different stress types, was analyzed using HDX-MS and through comparison with receptor-binding activity. It was found that HDX-MS, in combination with ion mobility separation, was able to identify conformational changes in G-CSF induced by stress, and a good correlation with the receptor-binding activity was demonstrated, which cannot be completely determined by conventional peptide mapping alone. The direct evaluation of biological activity using bioassay is absolutely imperative in biopharmaceutical development, but HDX-MS can provide the alternative information in a short time on the extent and location of the structural damage caused by stresses. Furthermore, the present study suggests the possibility of this system being a versatile evaluation method for the preservation stability of biopharmaceuticals.

  12. Quantification of genetically modified soya using strong anion exchange chromatography and time-of-flight mass spectrometry.

    Science.gov (United States)

    Chang, Po-Chih; Reddy, P Muralidhar; Ho, Yen-Peng

    2014-09-01

    Stable-isotope dimethyl labeling was applied to the quantification of genetically modified (GM) soya. The herbicide-resistant gene-related protein 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) was labeled using a dimethyl labeling reagent, formaldehyde-H2 or -D2. The identification and quantification of CP4 EPSPS was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The CP4 EPSPS protein was separated from high abundance proteins using strong anion exchange chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, the tryptic peptides from the samples and reference were labeled with formaldehyde-H2 and formaldehyde-D2, respectively. The two labeled pools were mixed and analyzed using MALDI-MS. The data showed a good correlation between the peak ratio of the H- and D-labeled peptides and the GM soya percentages at 0.5, 1, 3, and 5 %, with R (2) of 0.99. The labeling reagents are readily available. The labeling experiments and the detection procedures are simple. The approach is useful for the quantification of GM soya at a level as low as 0.5 %.

  13. Evaluation of strong cation exchange versus isoelectric focusing of peptides for multidimensional liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Slebos, Robbert J C; Brock, Jonathan W C; Winters, Nancy F; Stuart, Sarah R; Martinez, Misti A; Li, Ming; Chambers, Mathew C; Zimmerman, Lisa J; Ham, Amy J; Tabb, David L; Liebler, Daniel C

    2008-12-01

    Shotgun proteome analysis platforms based on multidimensional liquid chromatography-tandem mass spectrometry (LC-MS/MS) provide a powerful means to discover biomarker candidates in tissue specimens. Analysis platforms must balance sensitivity for peptide detection, reproducibility of detected peptide inventories and analytical throughput for protein amounts commonly present in tissue biospecimens (cation exchange (SCX) and isoelectric focusing (IEF) separations of peptides prior to LC-MS/MS analysis on a LTQ-Orbitrap hybrid instrument. IEF separations provided superior reproducibility and resolution for peptide fractionation from samples corresponding to both large (100 microg) and small (10 microg) protein inputs. SCX generated more peptide and protein identifications than did IEF with small (10 microg) samples, whereas the two platforms yielded similar numbers of identifications with large (100 microg) samples. In nine replicate analyses of tryptic peptides from 50 microg colon adenocarcinoma protein, overlap in protein detection by the two platforms was 77% of all proteins detected by both methods combined. IEF more quickly approached maximal detection, with 90% of IEF-detectable medium abundance proteins (those detected with a total of 3-4 peptides) detected within three replicate analyses. In contrast, the SCX platform required six replicates to detect 90% of SCX-detectable medium abundance proteins. High reproducibility and efficient resolution of IEF peptide separations make the IEF platform superior to the SCX platform for biomarker discovery via shotgun proteomic analyses of tissue specimens.

  14. A membrane cell for on-line hydrogen/deuterium exchange to study protein folding and protein-protein interactions by mass spectrometry.

    Science.gov (United States)

    Astorga-Wells, Juan; Landreh, Michael; Johansson, Jan; Bergman, Tomas; Jörnvall, Hans

    2011-09-01

    A membrane cell for hydrogen and deuterium exchange on-line with mass spectrometry has been developed to monitor protein-protein interactions and protein conformations. It consists of two channels separated by a semipermeable membrane, where one channel carries the protein sample and the other deuterium oxide. The membrane allows transfer of deuterium oxide into the sample flow. The labeling time is controlled via the flow rate in the sample channel. This cell was validated against three models commonly used in hydrogen-deuterium exchange mass spectrometry: monitoring of folded and unfolded states in a protein, mapping the protein secondary structure at the peptide level, and detection of protein and antibody interactions. The system avoids the conventionally used sample dilution and handling, allowing for potential automation.

  15. A Membrane Cell for On-line Hydrogen/Deuterium Exchange to Study Protein Folding and Protein-Protein Interactions by Mass Spectrometry*

    Science.gov (United States)

    Astorga-Wells, Juan; Landreh, Michael; Johansson, Jan; Bergman, Tomas; Jörnvall, Hans

    2011-01-01

    A membrane cell for hydrogen and deuterium exchange on-line with mass spectrometry has been developed to monitor protein-protein interactions and protein conformations. It consists of two channels separated by a semipermeable membrane, where one channel carries the protein sample and the other deuterium oxide. The membrane allows transfer of deuterium oxide into the sample flow. The labeling time is controlled via the flow rate in the sample channel. This cell was validated against three models commonly used in hydrogen-deuterium exchange mass spectrometry: monitoring of folded and unfolded states in a protein, mapping the protein secondary structure at the peptide level, and detection of protein and antibody interactions. The system avoids the conventionally used sample dilution and handling, allowing for potential automation. PMID:21610101

  16. Effective Application of Bicelles for Conformational Analysis of G Protein-Coupled Receptors by Hydrogen/Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Duc, Nguyen Minh; Du, Yang; Thorsen, Thor S.; Lee, Su Youn; Zhang, Cheng; Kato, Hideaki; Kobilka, Brian K.; Chung, Ka Young

    2015-05-01

    G protein-coupled receptors (GPCRs) have important roles in physiology and pathology, and 40% of drugs currently on the market target GPCRs for the treatment of various diseases. Because of their therapeutic importance, the structural mechanism of GPCR signaling is of great interest in the field of drug discovery. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a useful tool for analyzing ligand binding sites, the protein-protein interaction interface, and conformational changes of proteins. However, its application to GPCRs has been limited for various reasons, including the hydrophobic nature of GPCRs and the use of detergents in their preparation. In the present study, we tested the application of bicelles as a means of solubilizing GPCRs for HDX-MS studies. GPCRs (e.g., β2-adrenergic receptor [β2AR], μ-opioid receptor, and protease-activated receptor 1) solubilized in bicelles produced better sequence coverage (greater than 90%) than GPCRs solubilized in n-dodecyl-β-D-maltopyranoside (DDM), suggesting that bicelles are a more effective method of solubilization for HDX-MS studies. The HDX-MS profile of β2AR in bicelles showed that transmembrane domains (TMs) undergo lower deuterium uptake than intracellular or extracellular regions, which is consistent with the fact that the TMs are highly ordered and embedded in bicelles. The overall HDX-MS profiles of β2AR solubilized in bicelles and in DDM were similar except for intracellular loop 3. Interestingly, we detected EX1 kinetics, an important phenomenon in protein dynamics, at the C-terminus of TM6 in β2AR. In conclusion, we suggest the application of bicelles as a useful method for solubilizing GPCRs for conformational analysis by HDX-MS.

  17. Differential isotopic enrichment to facilitate characterization of asymmetric multimeric proteins using hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Goswami, Devrishi; Tuske, Steve; Pascal, Bruce D; Bauman, Joseph D; Patel, Disha; Arnold, Eddy; Griffin, Patrick R

    2015-04-07

    Hydrogen/deuterium exchange (HDX) coupled to mass spectrometry has emerged as a powerful tool for analyzing the conformational dynamics of protein-ligand and protein-protein interactions. Recent advances in instrumentation and methodology have expanded the utility of HDX for the analysis of large and complex proteins; however, asymmetric dimers with shared amino acid sequence present a unique challenge for HDX because assignment of peptides with identical sequence to their subunit of origin remains ambiguous. Here we report the use of differential isotopic labeling to facilitate HDX analysis of multimers using HIV-1 reverse transcriptase (RT) as a model. RT is an asymmetric heterodimer of 51 kDa (p51) and 66 kDa (p66) subunits. The first 440 residues of p51 and p66 are identical. In this study differentially labeled RT was reconstituted from isotopically enriched ((15)N-labeled) p51 and unlabeled p66. To enable detection of (15)N-deuterated RT peptides, the software HDX Workbench was modified to follow a 100% (15)N model. Our results demonstrated that (15)N enrichment of p51 did not affect its conformational dynamics compared to unlabeled p51, but (15)N-labeled p51 did show different conformational dynamics than p66 in the RT heterodimer. Differential HDX-MS of isotopically labeled RT in the presence of the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz (EFV) showed subunit-specific perturbation in the rate of HDX consistent with previously published results and the RT-EFV cocrystal structure.

  18. Ambient ionization mass spectrometry

    Science.gov (United States)

    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. Automated Data Reduction for Hydrogen/Deuterium Exchange Experiments, Enabled by High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Kazazic, Sasa; Zhang, Hui-Min; Schaub, Tanner M.; Emmett, Mark R.; Hendrickson, Christopher L.; Blakney, Gregory T.; Marshall, Alan G.

    2010-01-01

    Mass analysis of proteolytic fragment peptides following hydrogen/deuterium exchange offers a general measure of solvent accessibility/hydrogen bonding (and thus conformation) of solution-phase proteins and their complexes. The primary problem in such mass analyses is reliable and rapid assignment of mass spectral peaks to the correct charge state and degree of deuteration of each fragment peptide, in the presence of substantial overlap between isotopic distributions of target peptides, autolysis products, and other interferant species. Here, we show that at sufficiently high mass resolving power (m/Δm50% ≥ 100,000), it becomes possible to resolve enough of those overlaps so that automated data reduction becomes possible, based on the actual elemental composition of each peptide without the need to deconvolve isotopic distributions. We demonstrate automated, rapid, reliable assignment of peptide masses from H/D exchange experiments, based on electrospray ionization FT-ICR mass spectra from H/D exchange of solution-phase myoglobin. Combined with previously demonstrated automated data acquisition for such experiments, the present data reduction algorithm enhances automation (and thus expands generality and applicability) for high-resolution mass spectrometry- based analysis of H/D exchange of solution-phase proteins. PMID:20116280

  20. Miniaturization and Mass Spectrometry

    NARCIS (Netherlands)

    le Gac, S.; le Gac, Severine; van den Berg, Albert; van den Berg, A.; Unknown, [Unknown

    2009-01-01

    With this book we want to illustrate how two quickly growing fields of instrumentation and technology, both applied to life sciences, mass spectrometry and microfluidics (or microfabrication) naturally came to meet at the end of the last century and how this marriage impacts on several types of

  1. Simultaneous determination of 13 carbohydrates using high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry.

    Science.gov (United States)

    Zhao, Dan; Feng, Feng; Yuan, Fei; Su, Jin; Cheng, Yan; Wu, Hanqiu; Song, Kun; Nie, Bo; Yu, Lian; Zhang, Feng

    2017-04-01

    A simple, accurate, and highly sensitive method was developed for the determination of 13 carbohydrates in polysaccharide of Spirulina platensis based on high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry. Samples were extracted with deionized water using ultrasonic-assisted extraction, and the ultrasound-assisted extraction conditions were optimized by Box-Behnken design. Then the extracted polysaccharide was hydrolyzed by adding 1 mol/L trifluoroacetic acid before determination by high-performance anion-exchange chromatography coupled with pulsed amperometric detection and confirmed by high-performance anion-exchange chromatography coupled with mass spectrometry. The high-performance anion-exchange chromatography coupled with pulsed amperometric detection method was performed on a CarboPac PA20 column by gradient elution using deionized water, 0.1 mol/L sodium hydroxide solution, and 0.4 mol/L sodium acetate solution. Excellent linearity was observed in the range of 0.05-10 mg/L. The average recoveries ranged from 80.7 to 121.7%. The limits of detection and limits of quantification for 13 carbohydrates were 0.02-0.10 and 0.2-1.2  μg/kg, respectively. The developed method has been successfully applied to ambient samples, and the results indicated that high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry could provide a rapid and accurate method for the simultaneous determination of carbohydrates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Difference in fibril core stability between two tau four-repeat domain proteins: a hydrogen-deuterium exchange coupled to mass spectrometry study.

    Science.gov (United States)

    Ramachandran, Gayathri; Udgaonkar, Jayant B

    2013-12-10

    One of the signatures of Alzheimer's disease and tauopathies is fibrillization of the microtubule-associated protein tau. The purpose of this study was to compare the high-resolution structure of fibrils formed by two different tau four-repeat domain constructs, tau4RD and tauK18, using hydrogen-deuterium exchange coupled to mass spectrometry as a tool. While the two fibrils are found to be constructed on similar structural principles, the tauK18 fibril has a slightly more stable core. This difference in fibril core stability appears to be reflective of the mechanistic differences in the aggregation pathways of the two proteins.

  3. Hydrogen/Deuterium Exchange Mass Spectrometry Reveals Specific Changes in the Local Flexibility of Plasminogen Activator Inhibitor 1 upon Binding to the Somatomedin B Domain of Vitronectin

    DEFF Research Database (Denmark)

    Trelle, Morten Beck; Hirschberg, Daniel; Jansson, Anna

    2012-01-01

    The native fold of plasminogen activator inhibitor 1 (PAI-1) represents an active metastable conformation that spontaneously converts to an inactive latent form. Binding of the somatomedin B domain (SMB) of the endogenous cofactor vitronectin to PAI-1 delays the transition to the latent state...... and increases the thermal stability of the protein dramatically. We have used hydrogen/deuterium exchange mass spectrometry to assess the inherent structural flexibility of PAI-1 and to monitor the changes induced by SMB binding. Our data show that the PAI-1 core consisting of β-sheet B is rather protected...

  4. Dissecting the Binding Mode of Low Affinity Phage Display Peptide Ligands to Protein Targets by Hydrogen/Deuterium Exchange Coupled to Mass Spectrometry

    DEFF Research Database (Denmark)

    Leurs, Ulrike; Lohse, Brian; Ming, Shonoi A

    2014-01-01

    of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize interactions of low affinity peptides with their cognate protein targets. The HDX-MS workflow was optimized to accurately detect low-affinity peptide-protein interactions by use of ion mobility, electron transfer dissociation, non......Phage display (PD) is frequently used to discover peptides capable of binding to biological protein targets. The structural characterization of peptide-protein complexes is often challenging due to their low binding affinities and high structural flexibility. Here, we investigate the use...

  5. Probing the Conformational and Functional Consequences of Disulfide Bond Engineering in Growth Hormone by Hydrogen-Deuterium Exchange Mass Spectrometry Coupled to Electron Transfer Dissociation

    DEFF Research Database (Denmark)

    Seger, Signe T; Breinholt, Jens; Faber, Johan H

    2015-01-01

    Human growth hormone (hGH), and its receptor interaction, is essential for cell growth. To stabilize a flexible loop between helices 3 and 4, while retaining affinity for the hGH receptor, we have engineered a new hGH variant (Q84C/Y143C). Here, we employ hydrogen-deuterium exchange mass...... spectrometry (HDX-MS) to map the impact of the new disulfide bond on the conformational dynamics of this new hGH variant. Compared to wild type hGH, the variant exhibits reduced loop dynamics, indicating a stabilizing effect of the introduced disulfide bond. Furthermore, the disulfide bond exhibits longer...

  6. Using Hydrogen/Deuterium Exchange Mass Spectrometry to Define the Specific Interactions of the Phospholipase A2 Superfamily with Lipid Substrates, Inhibitors, and Membranes*

    Science.gov (United States)

    Cao, Jian; Burke, John E.; Dennis, Edward A.

    2013-01-01

    The phospholipase A2 (PLA2) superfamily consists of 16 groups and many subgroups and constitutes a diverse set of enzymes that have a common catalytic activity due to convergent evolution. However, different PLA2 types have unique three-dimensional structures and catalytic residues as well as specific tissue localization and distinct biological functions. Understanding how the different PLA2 enzymes associate with phospholipid membranes, specific phospholipid substrate molecules, and inhibitors on a molecular basis has advanced in recent years due to the introduction of hydrogen/deuterium exchange mass spectrometry. Its theory, practical considerations, and application to understanding PLA2/membrane interactions are addressed. PMID:23209293

  7. Rapid Screening for Potential Epitopes Reactive with a Polycolonal Antibody by Solution-Phase H/D Exchange Monitored by FT-ICR Mass Spectrometry

    Science.gov (United States)

    Zhang, Qian; Noble, Kyle A.; Mao, Yuan; Young, Nicolas L.; Sathe, Shridhar K.; Roux, Kenneth H.; Marshall, Alan G.

    2013-07-01

    The potential epitopes of a recombinant food allergen protein, cashew Ana o 2, reactive to polyclonal antibodies, were mapped by solution-phase amide backbone H/D exchange (HDX) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Ana o 2 polyclonal antibodies were purified in the serum from a goat immunized with cashew nut extract. Antibodies were incubated with recombinant Ana o 2 (rAna o 2) to form antigen:polyclonal antibody (Ag:pAb) complexes. Complexed and uncomplexed (free) rAna o 2 were then subjected to HDX-MS analysis. Four regions protected from H/D exchange upon pAb binding are identified as potential epitopes and mapped onto a homologous model.

  8. Dissecting the effect of RNA aptamer binding on the dynamics of plasminogen activator inhibitor 1 using hydrogen/deuterium exchange mass spectrometry

    DEFF Research Database (Denmark)

    Trelle, Morten B; Dupont, Daniel Miotto; Madsen, Jeppe Buur

    2014-01-01

    RNA aptamers, selected from large synthetic libraries, are attracting increasing interest as protein ligands, with potential uses as prototype pharmaceuticals, conformational probes, and reagents for specific quantification of protein levels in biological samples. Very little is known, however......, about their effects on protein conformation and dynamics. We have employed hydrogen/deuterium exchange (HDX) mass spectrometry to study the effect of RNA aptamers on the structural flexibility of the serpin plasminogen activator inhibitor-1 (PAI-1). The aptamers have characteristic effects...... of the aptamers to PAI-1 is associated with substantial and widespread protection against deuterium uptake in PAI-1. The aptamers induce protection against exchange with the solvent both in the protein-aptamer interface as well as in other specific areas. Interestingly, the aptamers induce substantial protection...

  9. Assay of low deuterium enrichment of water by isotopic exchange with [U-13C3]acetone and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Yang, D; Diraison, F; Beylot, M; Brunengraber, D Z; Samols, M A; Anderson, V E; Brunengraber, H

    1998-05-01

    A sensitive assay of the 2H-enrichment of water based on the isotopic exchange between the hydrogens of water and of acetone in alkaline medium is described and validated. For low 2H-enrichments (0.008 to 0.5%), the sample is spiked with [U-13C3]acetone and NaOH. After exchange, 2H-enriched [U-13C3]acetone is extracted with chloroform and assayed by gas chromatography-mass spectrometry. With some instruments, ion-molecule reactions, resulting in increased baseline enrichment, are minimized by lowering the electron ionization energy from the usual 70 to 10 eV. The 2H-enrichment of water is amplified nearly sixfold in the M4/M3 ratio of [U-13C3]acetone. For high 2H-enrichments (0.25 to 100%), the use of unlabeled acetone suffices. After exchange, the mass isotopomer distribution of acetone is analyzed, yielding the 2H-enrichment of water. The assay with [U-13C3]acetone allows measuring the 2H-enrichment of water even in biological samples containing acetone. This technique is more rapid and economical than the classical isotope ratio mass spectrometric assay of the enrichment of hydrogen gas derived from the reduction of water.

  10. Evaluation of strong cation-exchange polymers for the determination of drugs by solid-phase extraction-liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fontanals, Núria; Miralles, Núria; Abdullah, Norhayati; Davies, Arlene; Gilart, Núria; Cormack, P A G

    2014-05-23

    This paper presents eight distinct strong cation-exchange resins, all of which were derived from precursor resins that had been synthesised using either precipitation polymerisation or non-aqueous dispersion polymerisation. The precursor resins were transformed into the corresponding strong cation-exchange resins by hypercrosslinking followed by polymer analogous reactions, to yield materials with high specific surface areas and strong cation-exchange character. These novel resins were then evaluated as strong cation-exchange (SCX) sorbents in the solid-phase extraction (SPE) of a group of drugs from aqueous samples. Following preliminary experiments, the two best-performing resins were then evaluated in solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE/LC-MS/MS) to determine a group of drugs from sewage samples. In general, use of these sorbents led to excellent recovery values (75-100%) for most of the target drugs and negligible matrix effects (ME) (<20% ion suppression/enhancement of the analyte signal), when 50mL and 25mL of effluent and influent sewage water samples, respectively, were percolated through the resins. Finally, a validated method based on SPE/LC-MS/MS was used to quantify the target drugs present in different sewage samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. In vivo metabolic investigation of moxifloxacin using liquid chromatography/electrospray ionization tandem mass spectrometry in combination with online hydrogen/deuterium exchange experiments.

    Science.gov (United States)

    Raju, B; Ramesh, M; Borkar, Roshan M; Srinivas, R; Padiya, Raju; Banerjee, Sanjay K

    2012-08-30

    Tuberculosis is a leading cause of death from an infectious disease and moxifloxacin is an effective drug as compared to other fluoroquinolones. To date only two metabolites of the drug are known. Therefore, the present study on characterization of hitherto unknown in vivo metabolites of moxifloxacin using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is undertaken. In vivo metabolites of moxifloxacin have been identified and characterized by using LC/ESI-MS/MS in combination with an online hydrogen/deuterium (H/D) exchange technique. To identify in vivo metabolites, blood, urine and faeces samples were collected after oral administration of moxifloxacin to Sprague-Dawley rats. The samples were prepared using an optimized sample preparation approach involving protein precipitation, liquid-liquid extraction followed by solid-phase extraction and LC/MS/MS analysis. A total of nine phase I and ten phase II metabolites of moxifloxacin have been identified in urine samples including N-sulphated, glucuronide and hydroxylated metabolites which are also observed in plasma samples. In faeces samples, only the N-sulphated metabolite is observed. The structures of metabolites have been elucidated based on fragmentation patterns, accurate mass measurements and online H/D exchange LC/MS/MS experiments. Online H/D exchange experiments are used to support the identification and structural characterization of drug metabolites. A total of 19 in vivo metabolites of moxifloxacin have been characterized using LC/ESI-MS/MS in combination with accurate mass measurements and online H/D exchange experiments. The main phase I metabolites of moxifloxacin are hydroxylated, decarbonylated, desmethylated and desmethylhydroxylated metabolites which undergo subsequent phase II glucuronidation pathways. Copyright © 2012 John Wiley & Sons, Ltd.

  12. Determination of Equine Cytochrome c Backbone Amide Hydrogen/Deuterium Exchange Rates by Mass Spectrometry Using a Wider Time Window and Isotope Envelope

    Science.gov (United States)

    Hamuro, Yoshitomo

    2017-03-01

    A new strategy to analyze amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) data is proposed, utilizing a wider time window and isotope envelope analysis of each peptide. While most current scientific reports present HDX-MS data as a set of time-dependent deuteration levels of peptides, the ideal HDX-MS data presentation is a complete set of backbone amide hydrogen exchange rates. The ideal data set can provide single amide resolution, coverage of all exchange events, and the open/close ratio of each amide hydrogen in EX2 mechanism. Toward this goal, a typical HDX-MS protocol was modified in two aspects: measurement of a wider time window in HDX-MS experiments and deconvolution of isotope envelope of each peptide. Measurement of a wider time window enabled the observation of deuterium incorporation of most backbone amide hydrogens. Analysis of the isotope envelope instead of centroid value provides the deuterium distribution instead of the sum of deuteration levels in each peptide. A one-step, global-fitting algorithm optimized exchange rate and deuterium retention during the analysis of each amide hydrogen by fitting the deuterated isotope envelopes at all time points of all peptides in a region. Application of this strategy to cytochrome c yielded 97 out of 100 amide hydrogen exchange rates. A set of exchange rates determined by this approach is more appropriate for a patent or regulatory filing of a biopharmaceutical than a set of peptide deuteration levels obtained by a typical protocol. A wider time window of this method also eliminates false negatives in protein-ligand binding site identification.

  13. Observation of hydrogen-deuterium exchange of ubiquitin by direct analysis of electrospray capillary-skimmer dissociation with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Akashi, S; Naito, Y; Takio, K

    1999-11-01

    The structure of ubiquitin, a small cytoplasmic protein with an extended beta-sheet and an alpha-helix surrounding a hydrophobic core, has been characterized by hydrogen-deuterium (H/D) exchange labeling in conjunction with successive analysis by capillary-skimmer dissociation with electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS). The deuterium content of each fragment ion was investigated at different times, and the results indicate that the deuterium incorporation rate into the backbone amides of ubiquitin varied depending on the environment of the amide hydrogens. Amide hydrogens of the N-terminal beta-strand showed quite slow exchange while those of the 35-39 loop were exchanged within a short exposure time to deuterium oxide. It was also possible to evaluate the difference in hydrogen-bond stability. The present data are consistent with the structural features obtained by X-Ray and NMR analyses. Although some of the labeling information might be lost by the scrambling of amide protons during capillary-skimmer dissociation, the results demonstrate that the present method provides useful higher-order structural information for proteins.

  14. Oligosaccharide analysis by capillary-scale high-pH anion-exchange chromatography with on-line ion-trap mass spectrometry.

    Science.gov (United States)

    Bruggink, Cees; Wuhrer, Manfred; Koeleman, Carolien A M; Barreto, Victor; Liu, Yan; Pohl, Chris; Ingendoh, Arnd; Hokke, Cornelis H; Deelder, André M

    2005-12-27

    A capillary-scale high-pH anion-exchange chromatography (HPAEC) system for the analysis of carbohydrates was developed, in combination with two parallel on-line detection methods of sub-picomolar sensitivity: (1) pulsed amperometric detection (PAD); (2) capillary-scale desalting followed by electrospray ion-trap (IT) mass spectrometry (MS). The capillary chromatographic system combined the superb selectivity of HPAEC that allows routine separation of isomeric oligosaccharides with the information on monosaccharide sequence and linkage positions obtained by MS/MS fragmentation using the IT-MS. The applicability of the system in biomedical research was demonstrated by its use for the analysis of a urine sample of a GM1-gangliosidosis patient. Isomeric glycans in the sample could be resolved by HPAEC and assigned on the basis of the monosaccharide linkage information revealed by on-line IT-MS/MS.

  15. Epitope mapping of a monoclonal antibody against human thrombin by H/D-exchange mass spectrometry reveals selection of a diverse sequence in a highly conserved protein.

    Science.gov (United States)

    Baerga-Ortiz, Abel; Hughes, Carrie A; Mandell, Jeffrey G; Komives, Elizabeth A

    2002-06-01

    The epitope of a monoclonal antibody raised against human thrombin has been determined by hydrogen/deuterium exchange coupled to MALDI mass spectrometry. The antibody epitope was identified as the surface of thrombin that retained deuterium in the presence of the monoclonal antibody compared to control experiments in its absence. Covalent attachment of the antibody to protein G beads and efficient elution of the antigen after deuterium exchange afforded the analysis of all possible epitopes in a single MALDI mass spectrum. The epitope, which was discontinuous, consisting of two peptides close to anion-binding exosite I, was readily identified. The epitope overlapped with, but was not identical to, the thrombomodulin binding site, consistent with inhibition studies. The antibody bound specifically to human thrombin and not to murine or bovine thrombin, although these proteins share 86% identity with the human protein. Interestingly, the epitope turned out to be the more structured of two surface regions in which higher sequence variation between the three species is seen.

  16. Structure and Dynamics of NBD1 from CFTR Characterized Using Crystallography and Hydrogen/Deuterium Exchange Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, H.A.; Wang, C.; Zhao, X.; Hamuro, Y.; Conners, K.; Kearins, M.C.; Lu, F.; Sauder, J.M.; Molnar, K.S.; Coales, S.J.; Maloney, P.C.; Guggino, W.B.; Wetmore, D.R.; Weber, P.C.; Hunt, J.F. (SGX); (ExSAR); (Cystic); (JHU-MED); (Columbia)

    2012-04-30

    The {Delta}F508 mutation in nucleotide-binding domain 1 (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) is the predominant cause of cystic fibrosis. Previous biophysical studies on human F508 and {Delta}F508 domains showed only local structural changes restricted to residues 509-511 and only minor differences in folding rate and stability. These results were remarkable because {Delta}F508 was widely assumed to perturb domain folding based on the fact that it prevents trafficking of CFTR out of the endoplasmic reticulum. However, the previously reported crystal structures did not come from matched F508 and {Delta}F508 constructs, and the {Delta}F508 structure contained additional mutations that were required to obtain sufficient protein solubility. In this article, we present additional biophysical studies of NBD1 designed to address these ambiguities. Mass spectral measurements of backbone amide {sup 1}H/{sup 2}H exchange rates in matched F508 and {Delta}F508 constructs reveal that {Delta}F508 increases backbone dynamics at residues 509-511 and the adjacent protein segments but not elsewhere in NBD1. These measurements also confirm a high level of flexibility in the protein segments exhibiting variable conformations in the crystal structures. We additionally present crystal structures of a broader set of human NBD1 constructs, including one harboring the native F508 residue and others harboring the {Delta}F508 mutation in the presence of fewer and different solubilizing mutations. The only consistent conformational difference is observed at residues 509-511. The side chain of residue V510 in this loop is mostly buried in all non-{Delta}F508 structures but completely solvent exposed in all {Delta}F508 structures. These results reinforce the importance of the perturbation {Delta}F508 causes in the surface topography of NBD1 in a region likely to mediate contact with the transmembrane domains of CFTR. However, they also suggest that increased

  17. Improved plasma free metadrenaline analysis requires mixed mode cation exchange solid-phase extraction prior to liquid chromatography tandem mass spectrometry detection.

    Science.gov (United States)

    Clarke, Michael W; Cooke, Brian; Hoad, Kirsten; Glendenning, Paul

    2011-07-01

    The investigation and effective management of phaeochromocytoma involves biochemical measurement of either conjugated total urine or plasma free metadrenalines. Current analytical methods include enzyme-linked immunosorbent assays, high-performance liquid chromatography (HPLC) with electrochemical detection (ECD) or liquid chromatography tandem mass spectrometry (LCMS/MS). Since the first two methods are either extremely laborious, necessitate low sample run numbers, result in slow turnaround times or are subject to analytical interference, a robust, routine clinical method is not achievable. We established a novel sample preparation method to measure plasma free metadrenalines using LCMS/MS. Three different solid-phase extraction (SPE) methods were compared: hydrophilic-lipophilic balance sorbent (HLB), weak cation exchange (WCX) and mixed mode cation exchange (MCX) and their ability to remove interfering compounds prior to LCMS/MS analysis. Maximum recovery of plasma free metadrenaline and plasma free normetadrenaline were achieved by positively charging compounds prior to SPE application. Compared with HLB and WCX cartridges, MCX extraction resulted in chromatography without co-eluting interference with superior assay precision and accuracy. Additionally, samples that could not be quantified because of interference using HPLC/ECD could be readily assayed using this new method. The use of the MCX SPE method with LCMS/MS detection provides an improved assay to measure plasma free metadrenalines in comparison to many available alternative methods.

  18. Rapid comprehensive amino acid analysis by liquid chromatography/tandem mass spectrometry: comparison to cation exchange with post-column ninhydrin detection.

    Science.gov (United States)

    Dietzen, Dennis J; Weindel, Annette L; Carayannopoulos, Mary O; Landt, Michael; Normansell, Ellen T; Reimschisel, Tyler E; Smith, Carl H

    2008-11-01

    Ion-exchange chromatography with ninhydrin detection remains the gold standard for detecting inborn errors of amino acid catabolism and transport. Disadvantages of such analysis include long chromatography times and interference from other ninhydrin-positive compounds. The aim of this project was to develop a more rapid and specific technique using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Optimal fragmentation patterns for 32 amino acids were determined on a triple quadrupole mass spectrometer following butylation. Chromatographic characteristics of each of the amino acids were determined using C8 reversed-phase chromatography with 20% acetonitrile/0.1% formic acid as isocratic mobile phase. Quantitation using eleven deuterated internal standards was compared to cation exchange and ninhydrin detection on a Beckman 7300 system. Following methanol extraction and butylation, determination of 32 amino acids required 20 min. The dynamic range of each amino acid was generally 1-1000 micromol/L. Imprecision ranged from 7 to 23% (CV) over 6 months and recovery ranged from 88-125%. Deming regression with the Beckman 7300 yielded slopes from 0.4-1.2, intercepts from -21 to 65 micromol/L, correlation coefficients from 0.84-0.99 and Syx from 2-125 micromol/L. Isobaric amino acids were separated by chromatography (e.g. leucine, isoleucine) or by unique fragmentation (e.g., alanine, beta-alanine). LC/MS/MS is comparable to traditional LC-ninhydrin detection. Mass spectral detection shortens analysis times and reduces potential for interference in detecting inborn metabolic errors.

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

    Science.gov (United States)

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

    2013-12-30

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

  20. Rapid Conformational Analysis of Protein Drugs in Formulation by Hydrogen/Deuterium Exchange Mass Spectrometry (HDX-MS)

    DEFF Research Database (Denmark)

    Esmail Nazari, Zeinab; van de Weert, Marco; Bou-Assaf, George

    2016-01-01

    pharmaceutically relevant formulation conditions. Of significant practical utility, the methodology allows global HDX-MS analyses to be performed without refrigeration or external cooling of the setup. In Mode 1, we used DMSO-containing solvents for SPE, allowing the HDX-MS analysis to be performed at acceptable...... back exchange levels (cooling any components of the setup. In mode 2, SPE and chromatography were performed using fast isocratic elution at 0 °C resulting in a back exchange of 10-30%. Real-world applicability was demonstrated by HDX-MS analyses of interferon-β-1a...

  1. Mass spectrometry. [in organic chemistry

    Science.gov (United States)

    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.

  2. Instrumentation for mass spectrometry: 1997

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Protein Quantitation Using Mass Spectrometry

    Science.gov (United States)

    Zhang, Guoan; Ueberheide, Beatrix M.; Waldemarson, Sofia; Myung, Sunnie; Molloy, Kelly; Eriksson, Jan; Chait, Brian T.; Neubert, Thomas A.; Fenyö, David

    2013-01-01

    Mass spectrometry is a method of choice for quantifying low-abundance proteins and peptides in many biological studies. Here, we describe a range of computational aspects of protein and peptide quantitation, including methods for finding and integrating mass spectrometric peptide peaks, and detecting interference to obtain a robust measure of the amount of proteins present in samples. PMID:20835801

  4. Measuring dynamics in weakly structured regions of proteins using microfluidics-enabled subsecond H/D exchange mass spectrometry.

    Science.gov (United States)

    Rob, Tamanna; Liuni, Peter; Gill, Preet Kamal; Zhu, Shaolong; Balachandran, Naresh; Berti, Paul J; Wilson, Derek J

    2012-04-17

    This work introduces an integrated microfluidic device for measuring rapid H/D exchange (HDX) in proteins. By monitoring backbone amide HDX on the millisecond to low second time scale, we are able to characterize conformational dynamics in weakly structured regions, such as loops and molten globule-like domains that are inaccessible in conventional HDX experiments. The device accommodates the entire MS-based HDX workflow on a single chip with residence times sufficiently small (ca. 8 s) that back-exchange is negligible (≤5%), even without cooling. Components include an adjustable position capillary mixer providing a variable-time labeling pulse, a static mixer for HDX quenching, a proteolytic microreactor for rapid protein digestion, and on-chip electrospray ionization (ESI). In the present work, we characterize device performance using three model systems, each illustrating a different application of 'time-resolved' HDX. Ubiquitin is used to illustrate a crude, high throughput structural analysis based on a single subsecond HDX time-point. In experiments using cytochrome c, we distinguish dynamic behavior in loops, establishing a link between flexibility and interactions with the heme prosthetic group. Finally, we localize an unusually high 'burst-phase' of HDX in the large tetrameric enzyme DAHP synthase to a 'molten globule-like' region surrounding the active site.

  5. Synthesis of model humic substances: a mechanistic study using controllable H/D exchange and Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Zherebker, Alexander Ya; Airapetyan, David; Konstantinov, Andrey I; Kostyukevich, Yury I; Kononikhin, Alexey S; Popov, Igor A; Zaitsev, Kirill V; Nikolaev, Eugene N; Perminova, Irina V

    2015-07-07

    The products of the oxidative coupling of phenols are frequently used as synthetic analogues to natural humic substances (HS) for biomedical research. However, their molecular compositions and exact structures remain largely unknown. The objective of this study was to develop a novel approach for the molecular-level analysis of phenolic polymerisates that is capable of inventorying molecular constituents and resolving their distinct structural formulas. For this purpose, we have synthesized the model HS using the oxidative coupling of a specifically designed phenylpropanoic monomer, 3-(4-hydroxy-3-methoxyphenyl)-3-oxopropionic acid, to hydroquinone. We have characterized the synthesized model HS using high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS), (1)H NMR spectroscopy, and controllable hydrogen/deuterium (H/D) exchange. We succeeded in the molecular inventory of the model HS. The assigned molecular formulas occupied the substantial space of CHO compositions in the Van Krevelen diagram with a maximum density found in the regions of tannins and lignins, resembling those of natural HS. To identify the exact structural formulas of the individual constituents in the model HS, we have applied selective H/D exchange of non-labile backbone protons by a choice of basic or acidic catalytic conditions followed by FTICR MS. The determined formulas allowed us to verify the proposed pathways of hydroxylation and carboxylation in the course of the phenolic coupling and to identify the acetylation of aromatic rings as an important side reaction. We conclude that the proposed analytical approach may be used to identify the molecular carriers of biological activity within the phenolic polymerisates and eventually within natural HS.

  6. Mechanism and kinetics of tyrosinase inhibition by glycolic acid: a study using conventional spectroscopy methods and hydrogen/deuterium exchange coupling with mass spectrometry.

    Science.gov (United States)

    Ma, Da; Tu, Zong-Cai; Wang, Hui; Zhang, Lu; He, Na; McClements, David Julian

    2017-01-25

    Tyrosinase is an enzyme that promotes enzymatic browning of fruits and vegetables, thereby reducing product quality. A variety of analytical tools were used to characterize the interactions between tyrosinase and a natural tyrosinase inhibitor (glycolic acid). Hydrogen/deuterium exchange coupling with mass spectrometry (HDX-MS) was used to elucidate the interaction mechanism between glycolic acid and tyrosinase. UV-visible, fluorescence and circular dichroism spectroscopy analysis indicated that glycolic acid inhibited tyrosinase activity in a mixed-type manner with an IC50 of 83 ± 14 μM. The results of these techniques suggested that glycolic acid bound to tyrosinase through hydrophobic attraction, and this interaction led to a pronounced conformational change of the enzyme molecules. HDX-MS analysis showed that the activity of tyrosinase was primarily inhibited by a structural perturbation of its active site (His 263). This study provides a comprehensive understanding of the interaction between glycolic acid and tyrosinase, which could lead to new approaches to control tyrosinase activity in foods and other products.

  7. Design and Validation of In-Source Atmospheric Pressure Photoionization Hydrogen/Deuterium Exchange Mass Spectrometry with Continuous Feeding of D2O

    Science.gov (United States)

    Acter, Thamina; Lee, Seulgidaun; Cho, Eunji; Jung, Maeng-Joon; Kim, Sunghwan

    2017-10-01

    In this study, continuous in-source hydrogen/deuterium exchange (HDX) atmospheric pressure photoionization (APPI) mass spectrometry (MS) with continuous feeding of D2O was developed and validated. D2O was continuously fed using a capillary line placed on the center of a metal plate positioned between the UV lamp and nebulizer. The proposed system overcomes the limitations of previously reported APPI HDX-MS approaches where deuterated solvents were premixed with sample solutions before ionization. This is particularly important for APPI because solvent composition can greatly influence ionization efficiency as well as the solubility of analytes. The experimental parameters for APPI HDX-MS with continuous feeding of D2O were optimized, and the optimized conditions were applied for the analysis of nitrogen-, oxygen-, and sulfur-containing compounds. The developed method was also applied for the analysis of the polar fraction of a petroleum sample. Thus, the data presented in this study clearly show that the proposed HDX approach can serve as an effective analytical tool for the structural analysis of complex mixtures. [Figure not available: see fulltext.

  8. Simultaneous detection of perchlorate and bromate using rapid high-performance ion exchange chromatography-tandem mass spectrometry and perchlorate removal in drinking water.

    Science.gov (United States)

    West, Danielle M; Mu, Ruipu; Gamagedara, Sanjeewa; Ma, Yinfa; Adams, Craig; Eichholz, Todd; Burken, Joel G; Shi, Honglan

    2015-06-01

    Perchlorate and bromate occurrence in drinking water causes health concerns due to their effects on thyroid function and carcinogenicity, respectively. The purpose of this study was threefold: (1) to advance a sensitive method for simultaneous rapid detection of perchlorate and bromate in drinking water system, (2) to systematically study the occurrence of these two contaminants in Missouri drinking water treatment systems, and (3) to examine effective sorbents for minimizing perchlorate in drinking water. A rapid high-performance ion exchange chromatography-tandem mass spectrometry (HPIC-MS/MS) method was advanced for simultaneous detection of perchlorate and bromate in drinking water. The HPIC-MS/MS method was rapid, required no preconcentration of the water samples, and had detection limits for perchlorate and bromate of 0.04 and 0.01 μg/L, respectively. The method was applied to determine perchlorate and bromate concentrations in total of 23 selected Missouri drinking water treatment systems during differing seasons. The water systems selected include different source waters: groundwater, lake water, river water, and groundwater influenced by surface water. The concentrations of perchlorate and bromate were lower than or near to method detection limits in most of the drinking water samples monitored. The removal of perchlorate by various adsorbents was studied. A cationic organoclay (TC-99) exhibited effective removal of perchlorate from drinking water matrices.

  9. Fast analysis of quaternary ammonium pesticides in food and beverages using cation-exchange chromatography coupled with isotope-dilution high-resolution mass spectrometry.

    Science.gov (United States)

    Nardin, Tiziana; Barnaba, Chiara; Abballe, Franco; Trenti, Gianmaria; Malacarne, Mario; Larcher, Roberto

    2017-10-01

    A fast separation based on cation-exchange liquid chromatography coupled with high-resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length-modified IonPac CS17 column (2 × 15 mm(2) ) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 μg/L for chlormequat, difenzoquat and mepiquat, and 3 μg/L for diquat and paraquat, while for drinking water a pre-analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Different conformational dynamics of PDZ1 and PDZ2 in full-length EBP50 analyzed by hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Park, Ji Young; Duc, Nguyen Minh; Kim, Dong Kyun; Lee, Su Youn; Li, Sheng; Seo, Min-Duk; Woods, Virgil L; Chung, Ka Young

    2015-08-01

    Ezrin-radixin-moesin-binding protein 50 (EBP50) is a scaffolding protein expressed in polarized epithelial cells in various organs, including the liver, kidney, and small intestine, in which it regulates the trafficking and targeting cellular proteins. EBP50 contains two postsynaptic density-95/disk-large/ZO-1 homology (PDZ) domains (e.g., PDZ1 and PDZ2) and an ezrin/radixin/moesin-binding (EB) domain. PDZ domains are one of the major scaffolding domains regulating protein-protein interactions with critical biological roles in cell polarity, migration, proliferation, recognition, and cell-cell interaction. PDZ1 and PDZ2 in EBP50 have different ligand selectivity, although several high-resolution structural studies of isolated PDZ1 and PDZ2 showed similar structures. We studied the conformations of full-length EBP50 and isolated PDZ1 and PDZ2 using hydrogen/deuterium exchange mass spectrometry (HDX-MS). The deuterium uptake profiles of isolated PDZ1 and PDZ2 were similar to those of full-length EBP50. Interestingly, PDZ1 was more dynamic than PDZ2, and these PDZ domains underwent different conformational changes upon ligand binding. These results might explain the differences in ligand-selectivity between PDZ1 and PDZ2.

  11. Advances in Clinical Mass Spectrometry.

    Science.gov (United States)

    French, D

    Although mass spectrometry has been used clinically for decades, the advent of immunoassay technology moved the clinical laboratory to more labor saving automated platforms requiring little if any sample preparation. It became clear, however, that immunoassays lacked sufficient sensitivity and specificity necessary for measurement of certain analytes or for measurement of analytes in specific patient populations. This limitation prompted clinical laboratories to revisit mass spectrometry which could additionally be used to develop assays for which there was no commercial source. In this chapter, the clinical applications of mass spectrometry in therapeutic drug monitoring, toxicology, and steroid hormone analysis will be reviewed. Technologic advances and new clinical applications will also be discussed. © 2017 Elsevier Inc. All rights reserved.

  12. Symposium on accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    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.

  13. New Automated and High-Throughput Quantitative Analysis of Urinary Ketones by Multifiber Exchange-Solid Phase Microextraction Coupled to Fast Gas Chromatography/Negative Chemical-Electron Ionization/Mass Spectrometry

    Science.gov (United States)

    Pacenti, Marco; Dugheri, Stefano; Traldi, Pietro; Degli Esposti, Filippo; Perchiazzi, Nicola; Franchi, Elena; Calamante, Massimo; Kikic, Ireneo; Alessi, Paolo; Bonacchi, Alice; Salvadori, Edoardo; Arcangeli, Giulio; Cupelli, Vincenzo

    2010-01-01

    The present research is focused on automation, miniaturization, and system interaction with high throughput for multiple and specific Direct Immersion-Solid Phase Microextraction/Fast Gas Chromatography analysis of the urinary ketones. The specific Mass Spectrometry instrumentation, capable of supporting such the automated changeover from Negative Chemical to Electron Ionization mode, as well as the automation of the preparation procedure by new device called MultiFiber Exchange, through change of the fibers, allowed a friendly use of mass spectrometry apparatus with a number of advantages including reduced analyst time and greater reproducibility (2.01–5.32%). The detection limits for the seven ketones were less than 0.004 mg/L. For an innovative powerful meaning in high-throughput routine, the generality of the structurally informative Mass Spectrometry fragmentation patterns together with the chromatographic separation and software automation are also investigated. PMID:20628512

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

    NARCIS (Netherlands)

    Kiss, A.; Smith, D.F.; Jungmann, JH|info:eu-repo/dai/nl/351240020; Heeren, R.M.A.|info:eu-repo/dai/nl/105188476

    2013-01-01

    RATIONALE: Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with

  15. Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Bertoletti, Laura; Regazzoni, Luca; Aldini, Giancarlo; Colombo, Raffaella; Abballe, Franco; Caccialanza, Gabriele; De Lorenzi, Ersilia

    2013-04-10

    In this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimised in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Structural Dynamics of Soluble Chloride Intracellular Channel Protein CLIC1 Examined by Amide Hydrogen-Deuterium Exchange Mass Spectrometry (DXMS)†

    Science.gov (United States)

    Stoychev, Stoyan H.; Nathaniel, Christos; Fanucchi, Sylvia; Brock, Melissa; Li, Sheng; Asmus, Kyle; Woods, Virgil L.; Dirr, Heini W.

    2009-01-01

    Chloride intracellular channel protein 1 (CLIC1) functions as an anion channel in plasma and nuclear membranes when its soluble monomeric form converts to an integral-membrane form. The transmembrane region of CLIC1 is located in its thioredoxin-like domain 1 but the mechanism whereby the protein converts to its membrane conformation has yet to be determined. Since channel formation in membranes is enhanced at low pH (5 to 5.5), a condition that is found at the surface of membranes, the structural dynamics of soluble CLIC1 was studied at pH 7 and at pH 5.5 in the absence of membranes by amide hydrogen-deuterium exchange mass spectrometry (DXMS). Rapid hydrogen exchange data indicate that CLIC1 displays a similar core structure at these pH values. Domain 1 is less stable than the all-helical domain 2 and, while the structure of domain 1 remains intact, its conformational flexibility is further increased in an acidic environment (pH 5.5). In the absence of membrane, an acidic environment appears to prime the solution structure of CLIC1 by destabilising domain 1 in order to lower the activation energy barrier for its conversion to the membrane-insertion conformation. The significantly enhanced H/D-exchange rates at pH 5.5 displayed by two segments (peptides 11-31 and 68-82) could be due to the protonation of acidic residues in salt bridges. One of these segments (peptide 11-31) includes part of the transmembrane region which, in the solution structure, consists of helix α1. This helix is intrinsically stable and is most likely retained in the membrane conformation. Strand β2, another element of the transmembrane region, displays a propensity to form a helical structure and has putative N- and C-capping motifs, suggesting that it too most likely forms a helix in a lipid bilayer. PMID:19650640

  17. Ion-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of veterinary drugs in organic fertilizers.

    Science.gov (United States)

    Zhao, Zhiyong; Zhang, Yanmei; Xuan, Yanfang; Song, Wei; Si, Wenshuai; Zhao, Zhihui; Rao, Qinxiong

    2016-06-01

    The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of potential risks to soil microbial communities and human health. We develop a robust and sensitive method to quantitatively determine 19 veterinary drugs (amantadine, sulfonamides and fluoroquinolones) in organic fertilizers. The method involved a simple solid-liquid extraction step using the combination of acetonitrile and McIlvaine buffer as extraction solvent, followed by cleanup with a solid-phase extraction cartridge containing polymeric mixed-mode anion-exchange sorbents. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to separate and detect target analytes. We particularly focused on the optimization of sample clean-up step: different diluents and dilution factors were tested. The developed method was validated in terms of linearity, recovery, precision, sensitivity and specificity. The recoveries of all the drugs ranged from 70.9% to 112.7% at three concentration levels, with the intra-day and inter-day relative standard deviation lower than 15.7%. The limits of quantification were between 1.0 and 10.0μg/kg for all the drugs. Matrix effect was minimized by matrix-matched calibration curves. The analytical method was successfully applied for the survey of veterinary drugs contamination in 20 compost samples. The results indicated that fluoroquinolones had higher incidence rate and mean concentration levels ranging from 31.9 to 308.7μg/kg compared with other drugs. We expect the method will provide the basis for risk assessment of veterinary drugs in organic fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Suspect screening of halogenated carboxylic acids in drinking water using ion exchange chromatography - high resolution (Orbitrap) mass spectrometry (IC-HRMS).

    Science.gov (United States)

    Gallidabino, Matteo D; Hamdan, Laurence; Murphy, Bronagh; Barron, Leon P

    2018-02-01

    Retrospective in silico screening of analytical data for the identification of new or emerging disinfection by-products in drinking waters could be useful to assess quality and potential hazards, as well as help implement mitigation procedures more rapidly. Herein, the first study coupling ion exchange chromatography (IC) with high resolution mass spectrometry (HRMS) for the determination of halogenated carboxylic acid disinfectant by-products is reported. Separation was achieved using a Metrohm A Supp 5 column and a Na2CO3/NaHCO3 gradient eluent from 1/0.31 to 10/3.1mM. A variety of solid phase extraction (SPE) sorbents were tested for added selectivity to organic ions and Isolute ENV+ cartridges were selected because of their best overall extraction performance. Method LODs were in the μgL-1 concentration range, with R2 ≥ 0.99 for all the analytes, and isobaric ions could be easily discriminated using HRMS. The method was applied to municipal drinking water. Targeted quantitative analysis revealed the presence of 10 haloacetic acids at levels not exceeding the limits set by WHO and USEPA. Furthermore, suspect screening for additional halogenated carboxylic acids via retrospective HRMS data analysis also indicated the presence of other iodinated HAAs and chlorinated propionic acids, of which one (i.e. monochloropropionic acid) is discussed here for the first time. Most importantly, several potential suspects could be eliminated from further consideration through HRMS data analysis alone. To our knowledge, this represents the first time that a retrospective IC-HRMS screen of halogenated carboxylic acids in drinking water has been reported. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Structural Dynamics of the GW182 Silencing Domain Including its RNA Recognition motif (RRM) Revealed by Hydrogen-Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Cieplak-Rotowska, Maja K.; Tarnowski, Krzysztof; Rubin, Marcin; Fabian, Marc R.; Sonenberg, Nahum; Dadlez, Michal; Niedzwiecka, Anna

    2017-10-01

    The human GW182 protein plays an essential role in micro(mi)RNA-dependent gene silencing. miRNA silencing is mediated, in part, by a GW182 C-terminal region called the silencing domain, which interacts with the poly(A) binding protein and the CCR4-NOT deadenylase complex to repress protein synthesis. Structural studies of this GW182 fragment are challenging due to its predicted intrinsically disordered character, except for its RRM domain. However, detailed insights into the properties of proteins containing disordered regions can be provided by hydrogen-deuterium exchange mass spectrometry (HDX/MS). In this work, we applied HDX/MS to define the structural state of the GW182 silencing domain. HDX/MS analysis revealed that this domain is clearly divided into a natively unstructured part, including the CCR4-NOT interacting motif 1, and a distinct RRM domain. The GW182 RRM has a very dynamic structure, since water molecules can penetrate the whole domain in 2 h. The finding of this high structural dynamics sheds new light on the RRM structure. Though this domain is one of the most frequently occurring canonical protein domains in eukaryotes, these results are - to our knowledge - the first HDX/MS characteristics of an RRM. The HDX/MS studies show also that the α2 helix of the RRM can display EX1 behavior after a freezing-thawing cycle. This means that the RRM structure is sensitive to environmental conditions and can change its conformation, which suggests that the state of the RRM containing proteins should be checked by HDX/MS in regard of the conformational uniformity. [Figure not available: see fulltext.

  20. Epitope mapping of inhibitory antibodies targeting the C2 domain of coagulation factor VIII by hydrogen-deuterium exchange mass spectrometry

    Science.gov (United States)

    Sevy, Alexander M.; Healey, John F.; Deng, Wei; Spiegel, P. Clint; Meeks, Shannon L.; Li, Renhao

    2014-01-01

    Summary Background The development of anti-factor VIII (fVIII) antibodies (inhibitors) is a significant complication in the management of patients with hemophilia A, leading to significant increases in morbidity and treatment cost. Using a panel of anti-fVIII monoclonal antibodies (MAbs) to different epitopes on fVIII, we recently have shown that epitope specificity, inhibitor kinetics, and time to maximum inhibition are more important than inhibitor titer in predicting response to fVIII and the combination of fVIII and recombinant factor VIIa. In particular, a subset of high-titer inhibitors responded to high dose fVIII, which would not be predicted based on their inhibitor titer alone. Thus the ability to quickly map the epitope spectrum of patient plasma using a clinically feasible assay may fundamentally change how clinicians approach the treatment of high-titer inhibitor patients. Objectives To map the epitopes of anti-fVIII MAbs, of which 3 are classical inhibitors and one non-classical, using hydrogen-deuterium exchange coupled with liquid chromatography-mass spectrometry (HDX-MS). Methods Binding epitopes of 4 MAbs targeting fVIII C2 domain were mapped using HDX-MS. Results The epitopes determined by HDX-MS are consistent with those obtained earlier through structural characterization and antibody competition assays. In addition classical and non-classical inhibitor epitopes could be distinguished using a limited subset of C2-derived peptic fragments. Conclusion Our results demonstrate the effectiveness and robustness of the HDX-MS method for epitope mapping and suggest a potential role of rapid mapping of fVIII inhibitor epitopes in facilitating individualized treatment of inhibitor patients. PMID:24152306

  1. Hydrogen/Deuterium Exchange Mass Spectrometry and Site-Directed Disulfide Cross-Linking Suggest an Important Dynamic Interface between the Two Lysostaphin Domains

    Science.gov (United States)

    Lu, Hai-Rong; Gu, Mei-Gang; Huang, Qiang; Huang, Jin-Jiang; Lu, Wan-Ying; Lu, Hong

    2013-01-01

    Lysostaphin is a peptidoglycan hydrolase secreted by Staphylococcus simulans. It can specifically lyse Staphylococcus aureus and is being tested as a novel antibacterial agent. The protein contains an N-terminal catalytic domain and a C-terminal cell wall targeting domain. Although the two domains from homologous enzymes were structurally determined, the structural organization of lysostaphin domains remains unknown. We used hydrogen/deuterium exchange mass spectrometry (H/DX-MS) and site-directed disulfide cross-linking to probe the interface between the lysostaphin catalytic and targeting domains. H/DX-MS-mediated comparison of peptides from full-length lysostaphin and the separated domains identified four peptides of lower solvent accessibility in the full-length protein. Cross-linking analysis using cysteine pair substitutions within those peptides showed that two pairs of cysteines can form disulfide bonds, supporting the domain association role of the targeted peptides. The cross-linked mutant exhibited a binding capacity to S. aureus that was similar to that of the wild-type protein but reduced bacteriolytic activity probably because of restraint in conformation. The diminished activity was further reduced with increasing NaCl concentrations that can cause contractions of bacterial peptidoglycan. The lytic activity, however, could be fully recovered by reducing the disulfide bonds. These results suggest that lysostaphin may require dynamic association of the two domains for coordinating substrate binding and target cleavage on the elastic peptidoglycan. Our study will help develop site-specific PEGylated lysostaphin to treat systemic S. aureus infections. PMID:23380729

  2. Mass Spectrometry in Polymer Chemistry

    CERN Document Server

    Barner-Kowollik, Christopher; Falkenhagen, Jana; Weidner, Steffen

    2011-01-01

    Combining an up-to-date insight into mass-spectrometric polymer analysis beyond MALDI with application details of the instrumentation, this is a balanced and thorough presentation of the most important and widely used mass-spectrometric methods.Written by the world's most proficient experts in the field, the book focuses on the latest developments, covering such technologies and applications as ionization protocols, tandem and liquid chromatography mass spectrometry, gas-phase ion-separation techniques and automated data processing. Chapters on sample preparation, polymer degradation and the u

  3. Gas to particle conversion-gas exchange technique for direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Nishiguchi, Kohei; Utani, Keisuke; Gunther, Detlef; Ohata, Masaki

    2014-10-21

    A novel gas to particle conversion-gas exchange technique for the direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry (ICPMS) was proposed and demonstrated in the present study. The technique is based on a transfer of gas into particle, which can be directly analyzed by ICPMS. Particles from metal carbonyl gases such as Cr(CO)6, Mo(CO)6, and W(CO)6 are formed by reaction with ozone (O3) and ammonium (NH3) gases within a newly developed gas to particle conversion device (GPD). The reaction mechanism of the gas to particle conversion is based on either oxidation of metal carbonyl gas by O3 or agglomeration of metal oxide with ammonium nitrate (NH4NO3) which is generated by the reaction of O3 and NH3. To separate the reaction gases (remaining O3 and NH3) from the formed particles, a previously reported gas exchange device (GED) was used and the in argon stabilized analyte particles were directly introduced and measured by ICPMS. This new technique provided limits of detection (LOD) of 0.15 pL L(-1) (0.32 ng m(-3)), 0.02 pL L(-1) (0.07 ng m(-3)), and 0.01 pL L(-1) (0.07 ng m(-3)) for Cr(CO)6, Mo(CO)6, and W(CO)6, respectively, which were 4-5 orders of magnitude lower than those conventional applied for detecting these gases, e.g., gas chromatography with electron captured detector (GC-ECD) as well as Fourier transform-infrared spectroscopy (FT-IR). The achieved LODs were also similar or slightly better than those for ICPMS coupled to GC. Since the gas to particle conversion technique can achieve the direct measurement of metal carbonyl gases as well as the removal of reaction and ambient gases from metal carbonyl gases, the technique is considered to be well suited to monitor gas quality in semiconductor industry, engine exhaust gases, and or waste incineration products.

  4. Two tools for applying chromatographic retention data to the mass-based identification of peptides during hydrogen/deuterium exchange experiments by nano-liquid chromatography/matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Gershon, P D

    2010-12-15

    Two tools are described for integrating LC elution position with mass-based data in hydrogen-deuterium exchange (HDX) experiments by nano-liquid chromatography/matrix-assisted laser desorption/ionization mass spectrometry (nanoLC/MALDI-MS, a novel approach to HDX-MS). The first of these, 'TOF2H-Z Comparator', highlights peptides in HDX experiments that are potentially misidentified on the basis of mass alone. The program first calculates normalized values for the organic solvent concentration responsible for the elution of ions in nanoLC/MALDI HDX experiments. It then allows the solvent gradients for the multiple experiments contributing to an MS/MS-confirmed peptic peptide library to be brought into mutual alignment by iteratively re-modeling variables among LC parameters such as gradient shape, solvent species, fraction duration and LC dead time. Finally, using the program, high-probability chromatographic outliers can be flagged within HDX experimental data. The role of the second tool, 'TOF2H-XIC Comparator', is to normalize the LC chromatograms corresponding to all deuteration timepoints of all HDX experiments of a project, to a common reference. Accurate normalization facilitates the verification of chromatographic consistency between all ions whose spectral segments contribute to particular deuterium uptake plots. Gradient normalization in this manner revealed chromatographic inconsistencies between ions whose masses were either indistinguishable or separated by precise isotopic increments. Copyright © 2010 John Wiley & Sons, Ltd.

  5. Mass spectrometry. [review of techniques

    Science.gov (United States)

    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.

  6. Laser sputter neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

  7. Different conformational dynamics of β-arrestin1 and β-arrestin2 analyzed by hydrogen/deuterium exchange mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Youngjoo; Kim, Dong Kyun [School of Pharmacy, Sungkyunkwan University, Suwon (Korea, Republic of); Seo, Min-Duk [College of Pharmacy & Department of Molecular Science and Technology, Ajou University, Suwon (Korea, Republic of); Kim, Kyeong-Man [College of Pharmacy, Chonnam National University, Gwang-Ju (Korea, Republic of); Chung, Ka Young, E-mail: kychung2@skku.edu [School of Pharmacy, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-01-30

    Highlights: • The conformational dynamics of β-arrestin1 or β-arrestin2 were analyzed by HDX-MS. • β-Strands II through IV were more dynamic in β-arrestin2 than in β-arrestin1. • The middle loop was less dynamic in β-arrestin2 than in β-arrestin1. • Upon pre-activation by the R169E mutation, β-arrestins became more dynamic. • Pre-activation affected a wider region of β-arrestin1 compared to β-arrestin2. - Abstract: Arrestins have important roles in G protein-coupled receptor (GPCR) signaling including desensitization of GPCRs and G protein-independent signaling. There have been four arrestins identified: arrestin1, arrestin2 (e.g. β-arrestin1), arrestin3 (e.g. β-arrestin2), and arrestin4. β-Arrestin1 and β-arrestin2 are ubiquitously expressed and regulate a broad range of GPCRs, while arrestin1 and arrestin4 are expressed in the visual system. Although the functions of β-arrestin1 and β-arrestin2 widely overlap, β-arrestin2 has broader receptor selectivity, and a few studies have suggested that β-arrestin1 and β-arrestin2 have distinct cellular functions. Here, we compared the conformational dynamics of β-arrestin1 and β-arrestin2 by hydrogen/deuterium exchange mass spectrometry (HDX-MS). We also used the R169E mutant as a pre-activation model system. HDX-MS data revealed that β-strands II through IV were more dynamic in β-arrestin2 in the basal state, while the middle loop was more dynamic in β-arrestin1. With pre-activation, both β-arrestin1 and β-arrestin2 became more flexible, but broader regions of β-arrestin1 became flexible compared to β-arrestin2. The conformational differences between β-arrestin1 and β-arrestin2 in both the basal and pre-activated states might determine their different receptor selectivities and different cellular functions.

  8. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    Energy Technology Data Exchange (ETDEWEB)

    Beinhauer, Jana [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Bian, Liangqiao [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Fan, Hui [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Šebela, Marek [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Kukula, Maciej [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Barrera, Jose A. [Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); and others

    2015-02-09

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL{sup −1}, and demonstrated good linearity of R{sup 2} from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL{sup −1}. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified.

  9. Redox speciation of iron, manganese, and copper in cerebrospinal fluid by strong cation exchange chromatography - sector field inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Solovyev, Nikolay; Vinceti, Marco; Grill, Peter; Mandrioli, Jessica; Michalke, Bernhard

    2017-06-22

    A new method of simultaneous redox speciation of iron (II/III), manganese (II/III), and copper (I/II) in cerebrospinal fluid (CSF) has been designed. For the separation of redox species strong cation exchange chromatography (SCX) with isocratic elution was employed. Species were detected using inductively coupled plasma sector field mass spectrometry (ICP-sf-MS), operating at medium resolution. The following parameters were optimized: analytical column, eluent composition and pH, CSF injection volume and dilution factor. Analytical column Dionex IonPac CS5A RFIC 4*250 mm was found to retain and separate species of interest the most effectively under the isocratic elution with a buffer, containing 50 mM ammonium citrate, 7.0 mM pyridine-2,6-dicarboxylic acid at pH = 4.2 and flow rate of 0.8 L min-1. Injection volume of 50 μL with CSF sample dilution of 1/3 (v/v) with the eluent was shown to result in minimal matrix suppression. For species identification, retention time matching with standards was used. The stability of metalloproteins (ferritin, transferrin, and ceruloplasmin) under elution conditions was evaluated. For the quantification of redox species, external calibration was employed. To avoid column contamination, a blank was run after measurement and all quantification values were blank subtracted. For recovery checks, species quantification data was verified against total content of an element, measured by dynamic reaction cell ICP-MS. Recoveries (sum of quantified species vs. total element determinations) were 82.5 ± 22% (Mn), 92 ± 11% (Fe), and 88.7 ± 12% (Cu). The method was tested using 38 real CSF samples. Limits of detection (3σ) for the CSF samples were 0.5 μg L-1, 0.6 μg L-1, and 0.8 μg L-1 for Fe, Mn, and Cu species, respectively. Retention time precision was 1-7.5% (as RSD), whereas peak area RSDs were in the range 5-11%, both depending on the species. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Atomic mass spectrometry of materials

    Science.gov (United States)

    Anthony, J. M.; Matteson, S.; Duggan, J. L.; Elliott, P.; Marble, D.; McDaniel, F. D.; Weathers, D.

    1990-12-01

    Texas Instruments and the University of North Texas (UNT) are collaborating on the design of an accelerator mass spectrometry (AMS) system dedicated primarily to the analysis of impurities in electronic materials and metals. An AMS beamline consisting of high-resolution magnetic ( {M}/{dM } > 350) and electrostatic ( {E}/{dE } > 700) analysis followed by a surface barrier detector has been installed on the NEC 9SDH pelletron at UNT, and a "clean" ion source is under development. An existing ion source (NEC Cs sputter source) has been used in conjunction with the AMS beamline to generate computer controlled molecule-free mass analyses of solid samples. Through a careful choice of isotopes and charge states a robust algorithm can be developed for removing molecular interferences from the mass analysis for essentially all materials. Examples using graphite, Si and CdZnTe are discussed.

  11. Mass spectrometry in epigenetic research

    DEFF Research Database (Denmark)

    Beck, Hans Christian

    2010-01-01

    cancers has gained tremendous interest in recent years, and many of these inhibitors are currently undergoing clinical trials. Despite intense research, however, the exact molecular mechanisms of action of these molecules remain, to a wide extent, unclear. The recent application of mass spectrometry......-based proteomics techniques to histone biology has gained new insight into the function of the nucleosome: Novel posttranslational modifications have been discovered at the lateral surface of the nucleosome. These modifications regulate histone-DNA interactions, adding a new dimension to the epigenetic regulation...

  12. Protein Analysis by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Cindic, M.

    2008-04-01

    Full Text Available Soft ionization techniques, electrospray (ESI and matrix-assisted laser desorption/ionization (MALDI make the analysis of biomolecules by mass spectrometry (MS possible. MS is used for determination of the molecular weight of peptides and protein, sequence analysis, characterization of protein-ligand interactions etc. The detection limit, resolution and mass accuracy depend on instrument used (Table 1. Impurities (buffers, salts, detergents can reduce the ion intensities or even totally suppress them, so a separation method (chromatography, 2D-gel electrophoresis must be used for purification of the sample.Molecular mass of intact protein can be determined by ESI or MALDI MS. Multiply charged ions are produced by ESI MS, while singly charged ions are predominant in MALDI spectra (Fig. 2.Sequence analysis of proteins by MS can be performed using peptide mass fingerprint. In this method, proteins are separated by 2-D gel electrophoresis and digested with specific protease (Table 2 or digested and then separated by two-dimensional chromatography (Fig. 1. The obtained peptide mixtures are analyzed by MS or MALDI-TOF technique. The masses determined by MS are compared with calculated masses from database entries. Different algorithms have been developed for protein identification. Example of posttranslational modifications (N- and O-glycosylation and protein sequence complex analysis after dual digestion (endoproteinase digestion followed by endoglycosidase digestion is shown in Fig. 3.It is known that detection of peptides by MS is influenced by intrinsic properties like amino acid composition, the basicity of the C-terminal amino acid, hydrophobicity, etc. Arginine-containing peptides dominate in MS spectra of tryptic digest, so the chemical derivatization of lysine terminal residue by O-methilisourea or 2-methoxy-4,5-1H-imidazole was suggested (Fig. 4.The peptide mass fingerprint method can be improved further by peptide fragmentation using tandem

  13. Neuroscience and Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed.

    Science.gov (United States)

    Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2012-05-04

    Anion exchange high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry has been novelly applied to assess inorganic (iodide and iodate) and organic (3-iodotyrosine - MIT, and 3,5-diiodotyrosine - DIT) iodine species in a single chromatographic run. The optimized operating conditions (Dionex IonPac AS7, gradient elution with 175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase and flow rates within the 0.5-1.5 mL min(-1) range) have also been used to perform inorganic bromine speciation analysis (bromide and bromate). The developed method has been applied for determining the bio-available contents of iodine and bromine species in dialyzates from edible seaweed. Reverse phase high performance liquid chromatography (Zorbax Eclipse XDB-C8, gradient elution with 0.2% (m/m) acetic acid, and 0.2% (m/m) acetic acid in methanol, as mobile phases, and a constant flow rate of 0.75 mL min(-1)) also hyphenated with inductively coupled plasma-mass spectrometry was used to confirm the presence of organic iodine species (MIT and DIT) in the dialyzates. The verification of the presence of iodinated amino acids (MIT and DIT) in the extracts was also performed by reverse phase high performance liquid chromatography-electrospray ionization-mass spectrometry (LTQ Orbitrap). The developed methods have provided good repeatability (RSD values lower than 10% for both anion exchange and reverse phase separations) and analytical recoveries within the 90-105% range for all cases. The in vitro bio-availability method consisted of a simulated gastric and an intestinal digestion/dialysis (10 kDa molecular weight cut-off - MWCO) two-stage procedure. Iodide and MIT were the main bio-available species quantified, whereas bromide was the major bromine species found in the extracts. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Charge variants characterization of a monoclonal antibody by ion exchange chromatography coupled on-line to native mass spectrometry: Case study after a long-term storage at +5°C.

    Science.gov (United States)

    Leblanc, Y; Ramon, C; Bihoreau, N; Chevreux, G

    2017-03-24

    Numerous putative post-translational modifications may induce variations of monoclonal antibodies charge distribution that can potentially affect their biological activity. The characterization and the monitoring of these charge variants are critical quality requirements to ensure stability and process consistency. Charge variants are usually characterized by preparative ion exchange chromatography, collection of fractions and subsequent reverse-phase liquid chromatography with mass spectrometry analysis. While this process can be automatized by on-line two-dimensional chromatography, it remains often complex and time consuming. For this reason, a straightforward on-line charge variant analysis method is highly desirable and analytical laboratories are actively pursuing efforts to overcome this challenge. In this study, a mixed mode ion exchange chromatographic method using volatile salts and coupled on-line to native mass spectrometry was developed in association with a middle-up approach for a detailed characterization of monoclonal antibodies charge variants. An aged monoclonal antibody, presenting a complex charge variant profile was successfully investigated by this methodology as a case study. Results demonstrate that deamidation of the heavy chain was the major degradation pathway after long-term storage at 5°C while oxidation was rather low. The method was also very useful to identify all the clipped forms of the antibody. Copyright © 2017 LFB Biotechnologies. Published by Elsevier B.V. All rights reserved.

  16. NICHD Biomedical Mass Spectrometry Core Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The NICHD Biomedical Mass Spectrometry Core Facility was created under the auspices of the Office of the Scientific Director to provide high-end mass-spectrometric...

  17. Improved sensitivity using liquid chromatography mass spectrometry ...

    African Journals Online (AJOL)

    Triple quadrupole mass spectrometry (MS/MS) was used to confirm the identity of BMAA in cyanobacteria based on product ions. We show a 10-fold increase in sensitivity with the LC-MS method compared to the previously published gas chromatography mass spectrometry (GC-MS) method with pre-column derivatised ...

  18. Enumeration of non-labile oxygen atoms in dissolved organic matter by use of ¹⁶O/ ¹⁸O exchange and Fourier transform ion-cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Kostyukevich, Yury; Kononikhin, Alexey; Zherebker, Alexander; Popov, Igor; Perminova, Irina; Nikolaev, Eugene

    2014-10-01

    We report a simple approach for enumeration of non-labile oxygen atoms in individual molecules of dissolved organic matter (DOM), using acid-catalyzed (16)O/(18)O exchange and ultrahigh-resolution Fourier-transform ion-cyclotron-resonance mass spectrometry (FTICR-MS). We found that by dissolving DOM in H2 (18)O at 95 °C for 20 days it is possible to replace all oxygen atoms of DOM molecules (excluding oxygen from ether groups) with (18)O. The number of exchanges in each molecule can be determined using high-resolution FTICR. Using the proposed method we identified the number of non-labile oxygen atoms in 231 molecules composing DOM. Also, using a previously developed hydrogen-deuterium (H/D)-exchange approach we identified the number of labile hydrogen atoms in 450 individual molecular formulas. In addition, we observed that several backbone hydrogen atoms can be exchanged for deuterium under acidic conditions. The method can be used for structural and chemical characterization of individual DOM molecules, comparing different DOM samples, and investigation of biological pathways of DOM in the environment.

  19. Absorption Mode FTICR Mass Spectrometry Imaging

    NARCIS (Netherlands)

    Smith, D.F.; Kilgour, D.P.A.; Konijnenburg, M.; O'Connor, P.B.; Heeren, R.M.A.|info:eu-repo/dai/nl/105188476

    2013-01-01

    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

  20. Zero voltage mass spectrometry probes and systems

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, Robert Graham; Wleklinski, Michael Stanley; Bag, Soumabha; Li, Yafeng

    2017-10-10

    The invention generally relates to zero volt mass spectrometry probes and systems. In certain embodiments, the invention provides a system including a mass spectrometry probe including a porous material, and a mass spectrometer (bench-top or miniature mass spectrometer). The system operates without an application of voltage to the probe. In certain embodiments, the probe is oriented such that a distal end faces an inlet of the mass spectrometer. In other embodiments, the distal end of the probe is 5 mm or less from an inlet of the mass spectrometer.

  1. Introduction to mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Matthiesen, R.; Bunkenborg, J.

    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....... © Springer Science+Business Media, LLC 2013....

  2. Mass spectrometry of long-lived radionuclides

    Science.gov (United States)

    Becker, Johanna Sabine

    2003-10-01

    The capability of determining element concentrations at the trace and ultratrace level and isotope ratios is a main feature of inorganic mass spectrometry. The precise and accurate determination of isotope ratios of long-lived natural and artificial radionuclides is required, e.g. for their environmental monitoring and health control, for studying radionuclide migration, for age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, for quality assurance and determination of the burn-up of fuel material in a nuclear power plant, for reprocessing plants, nuclear material accounting and radioactive waste control. Inorganic mass spectrometry, especially inductively coupled plasma mass spectrometry (ICP-MS) as the most important inorganic mass spectrometric technique today, possesses excellent sensitivity, precision and good accuracy for isotope ratio measurements and practically no restriction with respect to the ionization potential of the element investigated—therefore, thermal ionization mass spectrometry (TIMS), which has been used as the dominant analytical technique for precise isotope ratio measurements of long-lived radionuclides for many decades, is being replaced increasingly by ICP-MS. In the last few years instrumental progress in improving figures of merit for the determination of isotope ratio measurements of long-lived radionuclides in ICP-MS has been achieved by the application of a multiple ion collector device (MC-ICP-MS) and the introduction of the collision cell interface in order to dissociate disturbing argon-based molecular ions, to reduce the kinetic energy of ions and neutralize the disturbing noble gas ions (e.g. of 129Xe + for the determination of 129I). The review describes the state of the art and the progress of different inorganic mass spectrometric techniques such as ICP-MS, laser ablation ICP-MS vs. TIMS, glow discharge mass spectrometry, secondary ion mass spectrometry, resonance ionization mass

  3. Enantioselectivity of mass spectrometry: challenges and promises.

    Science.gov (United States)

    Awad, Hanan; El-Aneed, Anas

    2013-01-01

    With the fast growing market of pure enantiomer drugs and bioactive molecules, new chiral-selective analytical tools have been instigated including the use of mass spectrometry (MS). Even though MS is one of the best analytical tools that has efficiently been used in several pharmaceutical and biological applications, traditionally MS is considered as a "chiral-blind" technique. This limitation is due to the MS inability to differentiate between two enantiomers of a chiral molecule based merely on their masses. Several approaches have been explored to assess the potential role of MS in chiral analysis. The first approach depends on the use of MS-hyphenated techniques utilizing fast and sensitive chiral separation tools such as liquid chromatography (LC), gas chromatography (GC), and capillary electrophoresis (CE) coupled to MS detector. More recently, several alternative separation techniques have been evaluated such as supercritical fluid chromatography (SFC) and capillary electrochromatography (CEC); the latter being a hybrid technique that combines the efficiency of CE with the selectivity of LC. The second approach is based on using the MS instrument solely for the chiral recognition. This method depends on the behavioral differences between enantiomers towards a foreign molecule and the ability of MS to monitor such differences. These behavioral differences can be divided into three types: (i) differences in the enantiomeric affinity for association with the chiral selector, (ii) differences of the enantiomeric exchange rate with a foreign reagent, and (iii) differences in the complex MS dissociation behaviors of the enantiomers. Most recently, ion mobility spectrometry was introduced to qualitatively and quantitatively evaluate chiral compounds. This article provides an overview of MS role in chiral analysis by discussing MS based methodologies and presenting the challenges and promises associated with each approach. © 2013 Wiley Periodicals, Inc.

  4. Electron spray ionization mass spectrometry and 2D {sup 31}P NMR for monitoring {sup 18}O/{sup 16}O isotope exchange and turnover rates of metabolic oligophosphates

    Energy Technology Data Exchange (ETDEWEB)

    Nemutlu, Emirhan [Mayo Clinic, Division of Cardiovascular Diseases, Department of Medicine, Rochester, MN (United States); University of Hacettepe, Department of Analytical Chemistry, Faculty of Pharmacy, Ankara (Turkey); Juranic, Nenad; Macura, Slobodan [Mayo Clinic, Department of Biochemistry and Molecular Biology, Rochester, MN (United States); Mayo Clinic, Analytical NMR Core Facility, Rochester, MN (United States); Zhang, Song; Terzic, Andre; Dzeja, Petras P. [Mayo Clinic, Division of Cardiovascular Diseases, Department of Medicine, Rochester, MN (United States); Ward, Lawrence E. [Mayo Clinic, CTSA Metabolomic Core Facility, Rochester, MN (United States); Dutta, Tumpa; Nair, K.S. [Mayo Clinic, CTSA Metabolomic Core Facility, Rochester, MN (United States); Mayo Clinic, Division of Endocrinology and Endocrine Research Unit, Rochester, MN (United States)

    2012-05-15

    A new method was here developed for the determination of {sup 18}O-labeling ratios in metabolic oligophosphates, such as ATP, at different phosphoryl moieties ({alpha}-, {beta}-, and {gamma}-ATP) using sensitive and rapid electrospray ionization mass spectrometry (ESI-MS). The ESI-MS-based method for monitoring of {sup 18}O/{sup 16}O exchange was validated with gas chromatography-mass spectrometry and 2D {sup 31}P NMR correlation spectroscopy, the current standard methods in labeling studies. Significant correlation was found between isotopomer selective 2D {sup 31}P NMR spectroscopy and isotopomer less selective ESI-MS method. Results demonstrate that ESI-MS provides a robust analytical platform for simultaneous determination of levels, {sup 18}O-labeling kinetics and turnover rates of {alpha}-, {beta}-, and {gamma}-phosphoryls in ATP molecule. Such method is advantageous for large scale dynamic phosphometabolomic profiling of metabolic networks and acquiring information on the status of probed cellular energetic system. (orig.)

  5. Pyrolysis - gas chromatography - mass spectrometry of lignins

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Saiz-Jimenez, C.; Gonzalez-Vila, F.J.

    1979-01-01

    Milled wood lignins from spruce, beech and bamboo were pyrolysed. The high-boiling products of pyrolysis were studied by GLC and mass spectrometry. The forty-three products identified provide information on the structural units of lignin.

  6. Quantitative determination of 22 primary aromatic amines by cation-exchange solid-phase extraction and liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Aznar, Margarita; Canellas, Elena; Nerín, Cristina

    2009-07-03

    Primary aromatic amines (PAAs) have been broadly studied due to their high toxicity. In this work a method for the analysis of 22 PAAs in aqueous simulants has been developed. The method is based on a solid-phase extraction step using cation-exchange cartridges and the subsequent analysis of the extracts by ultra-high-performance liquid chromatography with mass spectrometric detection. The recoveries obtained for all the amines analyzed ranged between 81 and 109%, linear range was between 0.03 and 75 microg L(-1), with the RSD values between 4.5 and 13.4% and an average value of 7.5% and limits of detection at microg L(-1) level. The method has been applied to two real samples obtained from migration experiments of polyurethane based laminates to simulant B (water with 3% (w/v) acetic acid) which represents the worst case for the migration of aromatic amines. The main amines found in both samples were methylenedianiline isomers, obtained from the corresponding residual diisocyanates used during polyurethane adhesive polymerization. The total amine concentration found was 26 and 6.3 microg of aniline equivalents per kg of food simulant.

  7. Computational Mass Spectrometry (Dagstuhl Seminar 13491)

    OpenAIRE

    Aebersbold, Ruedi; Kohlbacher, Oliver; Vitek, Olga

    2014-01-01

    The last decade has brought tremendous technological advances in mass spectrometry, which in turn have enabled new applications of mass spectrometry in the life sciences. Proteomics, metabolomics, lipidomics, glycomics and related fields have gotten a massive boost, which also resulted in vastly increased amount of data produced and increased complexity of these data sets. An efficient and accurate analysis of these data sets has become the key bottleneck in the field. The seminar 'Com...

  8. Approach to characterization of the higher order structure of disulfide-containing proteins using hydrogen/deuterium exchange and top-down mass spectrometry.

    Science.gov (United States)

    Wang, Guanbo; Kaltashov, Igor A

    2014-08-05

    Top-down hydrogen/deuterium exchange (HDX) with mass spectrometric (MS) detection has recently matured to become a potent biophysical tool capable of providing valuable information on higher order structure and conformational dynamics of proteins at an unprecedented level of structural detail. However, the scope of the proteins amenable to the analysis by top-down HDX MS still remains limited, with the protein size and the presence of disulfide bonds being the two most important limiting factors. While the limitations imposed by the physical size of the proteins gradually become more relaxed as the sensitivity, resolution and dynamic range of modern MS instrumentation continue to improve at an ever accelerating pace, the presence of the disulfide linkages remains a much less forgiving limitation even for the proteins of relatively modest size. To circumvent this problem, we introduce an online chemical reduction step following completion and quenching of the HDX reactions and prior to the top-down MS measurements of deuterium occupancy of individual backbone amides. Application of the new methodology to the top-down HDX MS characterization of a small (99 residue long) disulfide-containing protein β2-microglobulin allowed the backbone amide protection to be probed with nearly a single-residue resolution across the entire sequence. The high-resolution backbone protection pattern deduced from the top-down HDX MS measurements carried out under native conditions is in excellent agreement with the crystal structure of the protein and high-resolution NMR data, suggesting that introduction of the chemical reduction step to the top-down routine does not trigger hydrogen scrambling either during the electrospray ionization process or in the gas phase prior to the protein ion dissociation.

  9. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2011-01-01

    is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green...

  10. Affinity capture of biotinylated proteins at acidic conditions to facilitate hydrogen/deuterium exchange mass spectrometry analysis of multimeric protein complexes

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Jørgensen, Thomas J. D.; Koefoed, Klaus

    2013-01-01

    of biotinylated proteins even under the extreme conditions for hydrogen/deuterium exchange quenching i.e. pH 2.5 and 0 °C. This biotin-streptavidin capture strategy allows hydrogen/deuterium exchange to occur in proteins in solution and enables characterization of specific proteins in heteromultimeric protein...... receptor (EGFR). We present a workflow for biotinylation and characterization of recombinant antibodies and demonstrate affinity capture of biotinylated antibodies under hydrogen/deuterium exchange quench conditions by the biotin-streptavidin strategy....

  11. Analysis of mass spectrometry data in proteomics

    DEFF Research Database (Denmark)

    Matthiesen, Rune; Jensen, Ole N

    2008-01-01

    The systematic study of proteins and protein networks, that is, proteomics, calls for qualitative and quantitative analysis of proteins and peptides. Mass spectrometry (MS) is a key analytical technology in current proteomics and modern mass spectrometers generate large amounts of high-quality da...... some of the basic concepts and current approaches to the analysis of MS and MS/MS data in proteomics....

  12. Epitope Mapping of a 95 kDa Antigen in Complex with Antibody by Solution-Phase Amide Backbone H/D Exchange Monitored by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Zhang, Qian; Willison, LeAnna N.; Tripathi, Pallavi; Sathe, Shridhar K.; Roux, Kenneth H.; Emmett, Mark R.; Blakney, Greg T.; Zhang, Hui-Min; Marshall, Alan G.

    2011-01-01

    The epitopes of a homohexameric food allergen protein, cashew Ana o 2, identified by two monoclonal antibodies, 2B5 and 1F5, were mapped by solution-phase amide backbone H/D exchange (HDX) coupled with FT-ICR MS and the results compared to previous mapping by immunological and mutational analyses. Antibody 2B5 defines a conformational epitope and 1F5 defines a linear epitope. Intact murine IgG antibodies were incubated with recombinant Ana o 2 (rAna o 2) to form antigen:monoclonal antibody (Ag-mAb) complexes. MAb-complexed and uncomplexed (free) rAna o 2 were then subjected to HDX. HDX instrumentation and automation were optimized to achieve high sequence coverage by protease XIII digestion. The regions protected from H/D exchange upon antibody binding overlap and thus confirm the previously identified epitope-bearing segments: the first extension of HDX monitored by mass spectrometry to a full-length antigen-antibody complex in solution. PMID:21861454

  13. Mass Spectrometry Instrumentation in Proteomics

    DEFF Research Database (Denmark)

    Sprenger, Richard Remko; Roepstorff, Peter

    2012-01-01

    , Orbitrap and ion mobility instruments. Together they offer various and complementary capabilities in terms of ionization, sensitivity, speed, resolution, mass accuracy, dynamic range and methods of fragmentation. Mass spectrometers can acquire qualitative and quantitative information on a large scale....... In terms of desired outcome, cost and time, combining and choosing between available instrumentation and methodologies is key to find the best analytical strategy suiting a particular proteomics experiment....

  14. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Jixin, E-mail: jixin.qiao@risoe.d [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hou Xiaolin; Roos, Per [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Miro, Manuel [Department of Chemistry, Faculty of Sciences, University of the Balearic Islands, Carretera de Valldemossa km. 7.5, E-07122 Palma de Mallorca, Illes Balears (Spain)

    2011-01-31

    This paper reports an automated analytical method for rapid determination of plutonium isotopes ({sup 239}Pu and {sup 240}Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from matrix and interfering elements. The analytical results most distinctly demonstrated that the crosslinkage of the anion exchanger is a key parameter controlling the separation efficiency. AG 1-x4 type resin was selected as the most suitable sorbent material for analyte separation. Investigation of column size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 10{sup 3} to 10{sup 4}. The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green chemical credentials.

  15. Determination of mycophenolic acid in mest products using mixed mode reversed phase-anion exchange clean-up and liquid chromatography-high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Nielsen, Kristian Fog; Jacobsen, Thomas

    2008-01-01

    A method for determination of mycophenolic acid (MPA) in dry-cured ham, fermented sausage and liver pate is described. MPA was extracted from meat with bicarbonate-acetonitrile, further cleaned-up by mixed mode reversed phase-anion exchange and detected using a LC-MS system with electrospray...

  16. Study of fragmentation pattern and adsorption of 9-O-(triphenylsilyl)-10,11-dihydrocinchonidine on platinum by hydrogen/deuterium exchange using electrospray ionization ion-trap tandem mass spectrometry.

    Science.gov (United States)

    Szöllosi, György; Bucsi, Imre; Cserényi, Szabolcs; Bartók, Mihály

    2005-01-01

    We have studied the adsorption on a platinum (Pt) catalyst of two compounds utilizable as a chiral basic catalyst and a chiral modifier, dihydrocinchonidine (DHCD), and a new cinchona alkaloid derivative containing a bulky group, the Ph3SiO-DHCD molecule. The method of choice was the detection by electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS) of hydrogen/deuterium (H/D) exchange at room temperature, in tetrahydrofuran, at a D2 pressure of 1 bar. Based on the ESI-MS/MS spectrum of the new compound, we propose a mechanism for the formation of the silatropylium cation containing a Si-O bond. From the fragmentation pattern of Ph3SiO-DHCD it was confirmed that ESI-ion-trap MS/MS can be used to study the adsorption processes of complicated carbon compounds by investigating their H/D exchange reactions. In the case of Ph3SiO-DHCD, the results demonstrate that H/D exchange takes place mainly on the quinoline skeleton. However, the strong pi-bonded adsorption of the quinoline skeleton parallel with the imaginary plane of Pt is not preferred because the bulky Ph3Si group inhibits the multiple pi-bonded adsorption of the Ph3SiO-DHCD. Because of this hindrance the molecule was adsorbed tilted via the nonbonding electron pair of the N atom and C2' atom of the quinoline skeleton; consequently, mainly alkaloid-d1 and alkaloid-d2 are formed. 2005 John Wiley & Sons, Ltd.

  17. Mass spectrometry-assisted protease substrate screening

    DEFF Research Database (Denmark)

    Schlüter, Hartmut; Rykl, Jana; Thiemann, Joachim

    2007-01-01

    Since sequencing of the human genome was completed, more than 500 genes have been annotated as proteases. Exploring the physiological role of each protease requires the identification of their natural substrates. However, the endogenous substrates of many of the human proteases are as yet unknown......-phase chromatography they are analyzed by tandem mass spectrometry and the substrates identified by database searching. The proof of principle in this study is demonstrated by incubating immobilized human plasma proteins with thrombin and by identifying by tandem mass spectrometry the fibrinopeptides, released...

  18. A history of mass spectrometry in Australia.

    Science.gov (United States)

    Downard, Kevin M; de Laeter, John R

    2005-09-01

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

  19. A history of mass spectrometry in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Downard, K.M.; de Laeter, J.R. [University of Sydney, Sydney, NSW (Australia)

    2005-09-01

    An interest in mass spectrometry in Australia can be traced back to the 1920s with an early correspondence with Francis Aston who first visited these shores a decade earlier. The region has a rich tradition in both the development of the field and its application, from early measurements of ionization and appearance potentials by Jim Morrison at the Council for Scientific and Industrial Research (CSIR) around 1950 to the design and construction of instrumentation including the first use of a triple quadrupole mass spectrometer for tandem mass spectrometry, the first suite of programs to simulate ion optics (SIMION), the development of early TOF/TOF instruments and orthogonal acceleration and the local design and construction of several generations of a sensitive high-resolution ion microprobe (SHRIMP) instrument. Mass spectrometry has been exploited in the study and characterization of the constituents of this nation's unique flora and fauna from Australian apples, honey, tea plant and eucalyptus oil, snake, spider, fish and frog venoms, coal, oil, sediments and shale, environmental studies of groundwater to geochronological dating of limestone and granite, other terrestrial and meteoritic rocks and coral from the Great Barrier Reef. This article traces the history of mass spectrometry in its many guises and applications in the island continent of Australia. It focuses on contributions of scientists who played a major role in the early establishment of mass spectrometry in Australia. In general, those who are presently active in the field, and whose histories are incomplete, have been mentioned at best only briefly despite their important contributions to the field.

  20. Targeted quantitation of proteins by mass spectrometry.

    Science.gov (United States)

    Liebler, Daniel C; Zimmerman, Lisa J

    2013-06-04

    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.

  1. Chemistry Nobel Prize 2002-Mass Spectrometry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 4. Chemistry Nobel Prize 2002 - Mass Spectrometry. M Vairamani. Research News Volume 8 Issue 4 April 2003 pp 69-76. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/008/04/0069-0076 ...

  2. Characterization of microbial siderophores by mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Pluháček, Tomáš; Lemr, Karel; Ghosh, D.; Milde, D.; Novák, Jiří; Havlíček, Vladimír

    2016-01-01

    Roč. 35, č. 1 (2016), s. 35-47 ISSN 0277-7037 R&D Projects: GA MŠk(CZ) LD13038; GA ČR(CZ) GAP206/12/1150; GA MŠk(CZ) LO1509 Institutional support: RVO:61388971 Keywords : iron * siderophores * mass spectrometry Subject RIV: CE - Biochemistry Impact factor: 9.373, year: 2016

  3. Pyrolysis Mass Spectrometry of Complex Organic Materials.

    Science.gov (United States)

    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…

  4. Nanostructure-initiator mass spectrometry biometrics

    Energy Technology Data Exchange (ETDEWEB)

    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).

  5. Atmospheric pressure femtosecond laser imaging mass spectrometry

    Science.gov (United States)

    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.

  6. Characterization of Synthetic Peptides by Mass Spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI...

  7. Four decades of joy in mass spectrometry

    NARCIS (Netherlands)

    Nibbering, N.M.M.

    2006-01-01

    Tremendous developments in mass spectrometry have taken place in the last 40 years. This holds for both the science and the instrumental revolutions in this field. In chemistry the research was heavily focused on organic molecules that upon electron ionization fragmented via complex mechanistic

  8. Polymer and Additive Mass Spectrometry Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Shear, Trevor Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-06

    The use of mass spectrometry in fields related to polymers has increased significantly over the past three decades and will be explored in this literature review. The importance of this technique is highlighted when exploring how polymers degrade, verifying purchased materials, and as internal requirements change. The primary focus will be on four ionization techniques and the triple quadrupole and quadrupole / time-of-flight mass spectrometers. The advantages and limitations of each will also be explored.

  9. A Multidimensional System for Phosphopeptide Analysis Using TiO{sub 2} Enrichment and Ion-exchange Chromatography with Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kun; Yoo, Jisun; Kim, Eunmin; Kim, Jin Young; Kim, Young Hwan; Yoo, Jong Shin [Korea Basic Science Institute, Ochang (Korea, Republic of); Oh, Han Bin [Sogang Univ., Seoul (Korea, Republic of)

    2012-10-15

    Although offline enrichment of phosphorylated peptides is widely used, enrichment for phosphopeptides using TiO{sub 2} is often performed manually, which is labor-intensive and can lead to irreproducible results. To address the problems associated with offline enrichment and to improve the effectiveness of phosphopeptide detection, we developed an automated online enrichment system for phosphopeptide analysis. A standard protein mixture comprising BSA, fetuin, crystalline, α-casein and β-casein, and ovalbumin was assessed using our new system. Our multidimensional system has four main parts: a sample pump, a 20-mm TiO{sub 2}-based column, a weak anion-exchange, and a strong cation-exchange (2:1 WAX:SCX) separation column with LC/MS. Phosphorylated peptides were successfully detected using the TiO{sub 2}-based online system with little interference from nonphosphorylated peptides. Our results confirmed that our online enrichment system is a simple and efficient method for detecting phosphorylated peptides.

  10. Ligand induced structural isomerism in phosphine coordinated gold clusters revealed by ion mobility mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Baker, Erin S.; Laskin, Julia; Johnson, Grant E.

    2017-01-01

    Structural isomerism in ligated gold clusters is revealed using electrospray ionization ion mobility spectrometry mass spectrometry. Phosphine ligated Au8 clusters are shown to adopt more “extended” type structures with increasing exchange of methyldiphenylphosphine (MePPh2) for triphenylphosphine (PPh3). These ligand-dependant structure-property relationships are critical to applications of clusters in catalysis.

  11. Rapid and simultaneous determination of neptunium and plutonium in environmental samples using anion exchange chromatographic and sequential injection setup combined with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jixin Qiao; Hou, X.; Roos, P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Radiation Research Div., Roskilde (Denmark)); Miro, M. (Univ. of the Balearic Islands, Dept. of Chemistry, Faculty of Sciences, Palma de Mallorca (Spain))

    2010-03-15

    Full text: This paper presents an automated analytical method for the rapid and simultaneous determination of Pu and Np in the environmental samples. Anion exchange chromatographic column was incorporated in a sequential injection system to actualize the automated separation of Pu isotpes along with 237Np from the matrix elements and interfering radionuclides. K{sub 2}S{sub 2}O{sub 5}-conc. HNO{sub 3} was applied as redox reagents for the valence adjustment and stabilization of Pu(IV) and Np(IV). 242Pu preformed well as a tracer for both Pu isotopes and 237Np. It was observed that the cross-link and particle size of the resins had significant effluence on the separation efficiency and anion exchange resin Bio-Rad AG 1 x 4 with the particle size of 100-200 mesh was chosen as the optimum. The investigation on the capacity showed small-sized column packed with 2mL resin sufficed up to 50g of soil sample, which provides an advantage of low consumption of the resin and low generation of acid waste after the column washing. The analytical results for Pu and Np in three reference materials showed good agreement with the certified or reference values at the 0.05 significance level. Chemical yields of Pu and Np equally range from 80% to 100%, and the decontamination factors for uranium, thorium and lead were in the range of 103 to 104. The total time of separation for a single sample was < 2.5 hours, which extremely improve the analysis efficiency and reduces the labor intensity, as well as enables a rapid determination of Pu and Np in emergency situations. (author)

  12. Speciation analysis of calcium, iron, and zinc in casein phosphopeptide fractions from toddler milk-based formula by anion exchange and reversed-phase high-performance liquid chromatography-mass spectrometry/flame atomic-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miquel, Esther; Alegria, Amparo; Barbera, Reyes; Farre, Rosaura [University of Valencia, Nutrition and Food Chemistry, Faculty of Pharmacy, Burjassot, Valencia (Spain)

    2005-03-01

    Casein phosphopeptides (CPP) are phosphorylated casein-derived peptides that can be released by in-vitro or in-vivo enzymatic hydrolysis of {alpha}{sub s1}-casein, {alpha}{sub s2}-casein, and {beta}-casein (CN). Many of these peptides contain a highly polar acidic sequence of three phosphoseryl groups followed by two glutamic acid residues. These domains are binding sites for minerals such as calcium, iron, and zinc and play an important role in mineral bioavailability. The aim of this study was speciation analysis of calcium, iron, and zinc in CPP fractions from the soluble fraction of a toddler milk-based formula. Methods for CPP separation by anion-exchange high-performance liquid chromatography (AE-HPLC) were combined with CPP identification by reversed-phase high performance liquid chromatography-electrospray ionization mass spectrometry and determination of the calcium, iron, zinc, and phosphorus content of the fractions obtained by AE-HPLC. Calcium and phosphorus were detected in all the analyzed AE-HPLC fractions. Calcium and zinc could be bound to CPP derived from {alpha}{sub s1}-CN and {alpha}{sub s2}-CN in fraction 3. Iron could be bound to CPP in fraction 4 in which {beta}-CN(15-34)4P was present with the cluster sequence S(P)S(P)S(P)EE. The results obtained prove the different distribution of calcium, iron, and zinc in heterogeneous CPP fractions. (orig.)

  13. Accelerator mass spectrometry: state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

  14. Guideline on Isotope Dilution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Amy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-19

    Isotope dilution mass spectrometry is used to determine the concentration of an element of interest in a bulk sample. It is a destructive analysis technique that is applicable to a wide range of analytes and bulk sample types. With this method, a known amount of a rare isotope, or ‘spike’, of the element of interest is added to a known amount of sample. The element of interest is chemically purified from the bulk sample, the isotope ratio of the spiked sample is measured by mass spectrometry, and the concentration of the element of interest is calculated from this result. This method is widely used, although a mass spectrometer required for this analysis may be fairly expensive.

  15. Determination of residues of the plant growth regulator chlormequat in pears by ion-exchange high performance liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    Startin, J R; Hird, S J; Sykes, M D; Taylor, J C; Hill, A R

    1999-07-01

    We report a method which we have used routinely for the determination of chlormequat residues in pears. After extraction with methanol, determination was performed, without clean-up, by ion-exchange HPLC using an SCX column eluted with aqueous ammonium formate-methanol, and HPLC-MS with an electrospray interface. MS and MS-MS were employed concurrently, using selected ion monitoring and selected reaction monitoring, respectively, of the 35Cl and 37Cl isotopes of the chlormequat cation and the CID transitions of each of these precursors to the common product ion at m/z 58. The method was suitable for determinations at concentrations of chlormequat cation of 0.04 mg kg-1. Concentrations determined using the four signals were in good agreement (mean RSD 3%). The mean recovery of chlormequat cation at 0.16 mg kg-1, measured using the m/z 122-->58 signal, was 86% (RSD 7%) under repeatability conditions and 88% (RSD 15%) in routine application of the method over a 3 month period. Analysis of an in-house reference sample of pears, similarly analysed over the 3 month period, gave an RSD of 10% with a mean of 0.14 mg kg-1. Mean recovery at 0.016 mg kg-1, under repeatability conditions on two occasions, was 101% (RSD 6%) and 56% (RSD 12%).

  16. Space Applications of Mass Spectrometry. Chapter 31

    Science.gov (United States)

    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.

  17. Evolution of Orbitrap Mass Spectrometry Instrumentation

    Science.gov (United States)

    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.

  18. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry.

    Science.gov (United States)

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing; Dovichi, Norman J

    2015-06-01

    A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1×10(-7) M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10(-5) M angiotensin II. The system was also applied to the analysis of a 10(-4) mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10(-3) mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Laser-Cooling-Assisted Mass Spectrometry

    Science.gov (United States)

    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.

  20. Mass spectrometry imaging for biomedical applications.

    Science.gov (United States)

    Liu, Jiangjiang; Ouyang, Zheng

    2013-07-01

    The development of technologies for mass spectrometry imaging is of substantial research interest. Mass spectrometry is potentially capable of providing highly specific information about the distribution of compounds in tissues, with high sensitivity. The in-situ analysis needed for tissue imaging requires MS to be performed under conditions different from the traditional ones, typically with intensive sample preparation and optimized for pharmaceutical applications. In this paper we critically review the current status of MS imaging with different methods of sample ionization and discuss the 3D and quantitative imaging capabilities which need further development, the importance of the multi-modal imaging, and the balance between the pursuit of high-resolution imaging and the practical application of MS imaging in biomedicine.

  1. Mass spectrometry of fluorocarbon-labeled glycosphingolipids

    DEFF Research Database (Denmark)

    Li, Yunsen; Arigi, Emma; Eichert, Heather

    2010-01-01

    A method for generation of novel fluorocarbon derivatives of glycosphingolipids (GSLs) with high affinity for fluorocarbon phases has been developed, and their potential applications to mass spectrometry (MS)-based methodologies for glycosphingolipidomics have been investigated. Sphingolipid......, and four fungal glycosylinositol phosphorylceramides (GIPCs) were de-N-acylated, derivatized by prototype F-Tags, and recovered by solid phase extraction on fluorocarbon-derivatized silica (F-SPE). The efficacy of SCDase treatment of GIPCs was here demonstrated for the first time. Compatibility...

  2. Detection of Gunshot Residues Using Mass Spectrometry

    OpenAIRE

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

    2014-01-01

    In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful t...

  3. Conjugate heat and mass transfer in heat mass exchanger ducts

    CERN Document Server

    Zhang, Li-Zhi

    2013-01-01

    Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts bridges the gap between fundamentals and recent discoveries, making it a valuable tool for anyone looking to expand their knowledge of heat exchangers. The first book on the market to cover conjugate heat and mass transfer in heat exchangers, author Li-Zhi Zhang goes beyond the basics to cover recent advancements in equipment for energy use and environmental control (such as heat and moisture recovery ventilators, hollow fiber membrane modules for humidification/dehumidification, membrane modules for air purification, desi

  4. Determination of thermodynamic and kinetic properties of biomolecules by mass spectrometry.

    OpenAIRE

    Gülbakan Basri; Barylyuk Konstantin; Zenobi Renato

    2015-01-01

    Over the past two decades mass spectrometry (MS) has transformed the life sciences. The advances in understanding biomolecule structure and function by MS is progressing at an accelerated pace. MS has also largely been applied to study thermodynamic and kinetic structure of biomolecules. Herein we highlight the recent discussions about native mass spectrometry and studies about determining stable gas phase structures hydrogen/deuterium exchange studies about reaction kinetics and determinatio...

  5. Extratropical Stratosphere-Troposphere Mass Exchange

    Science.gov (United States)

    Schoeberl, Mark R.

    2004-01-01

    Understanding the exchange of gases between the stratosphere and the troposphere is important for determining how pollutants enter the stratosphere and how they leave. This study does a global analysis of that the exchange of mass between the stratosphere and the troposphere. While the exchange of mass is not the same as the exchange of constituents, you can t get the constituent exchange right if you have the mass exchange wrong. Thus this kind of calculation is an important test for models which also compute trace gas transport. In this study I computed the mass exchange for two assimilated data sets and a GCM. The models all agree that amount of mass descending from the stratosphere to the troposphere in the Northern Hemisphere extra tropics is approx. 10(exp 10) kg/s averaged over a year. The value for the Southern Hemisphere by about a factor of two. ( 10(exp 10) kg of air is the amount of air in 100 km x 100 km area with a depth of 100 m - roughly the size of the D.C. metro area to a depth of 300 feet.) Most people have the idea that most of the mass enters the stratosphere through the tropics. But this study shows that almost 5 times more mass enters the stratosphere through the extra-tropics. This mass, however, is quickly recycled out again. Thus the lower most stratosphere is a mixture of upper stratospheric air and tropospheric air. This is an important result for understanding the chemistry of the lower stratosphere.

  6. Optimization of collision/reaction gases for determination of 90Sr in atmospheric particulate matter by inductively coupled plasma tandem mass spectrometry after direct introduction of air via a gas-exchange device

    Science.gov (United States)

    Suzuki, Yoshinari; Ohara, Ryota; Matsunaga, Kirara

    2017-09-01

    Nuclear power plant accidents release radioactive strontium 90 (90Sr) into the environment. Monitoring of 90Sr, although important, is difficult and time consuming because it emits only beta radiation. We have developed a new analytical system that enables real-time analysis of 90Sr in atmospheric particulate matter with an analytical run time of only 10 min. Briefly, after passage of an air sample through an impactor, a small fraction of the sample is introduced into a gas-exchange device, where the air is replaced by Ar. Then the sample is directly introduced into an inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) system equipped with a collision/reaction cell to eliminate isobaric interferences on 90Sr from 90Zr+, 89Y1H+, and 90Y+. Experiments with various reaction gas conditions revealed that these interferences could be minimized under the following optimized conditions: 1.0 mL min- 1 O2, 10.0 mL min- 1 H2, and 1.0 mL min- 1 NH3. The estimated background equivalent concentration and estimated detection limit of the system were 9.7 × 10- 4 and 3.6 × 10- 4 ng m- 3, respectively, which are equivalent to 4.9 × 10- 6 and 1.8 × 10- 6 Bq cm- 3. Recoveries of Sr in PM2.5 measured by real-time analysis compared to those obtained by simultaneously collection on filter was 53 ± 23%, and using this recovery, the detection limit as PM2.5 was estimated to be 3.4 ± 1.5 × 10- 6 Bq cm- 3. That is, this system enabled detection of 90Sr at concentrations < 5 × 10- 6 Bq cm- 3 even considering the insufficient fusion/vaporization/ionization efficiency of Sr in PM2.5.

  7. Development and validation of a solid-phase extraction method using anion exchange sorbent for the analysis of cannabinoids in plasma and serum by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Gasse, Angela; Pfeiffer, Heidi; Köhler, Helga; Schürenkamp, Jennifer

    2016-07-01

    The aim of this work was to develop and validate a solid-phase extraction (SPE) method for the analysis of cannabinoids with emphasis on a very extensive and effective matrix reduction in order to ensure constant good results in selectivity and sensitivity regardless of the applied measuring technology. This was obtained by the use of an anion exchange sorbent (AXS) and the purposive ionic interaction between matrix components and this sorbent material. In a first step, the neutral cannabinoids ∆9-tetrahydrocannabinol (THC) and 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-THC) were eluted, leaving 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH) and the main interfering matrix components bound to the AXS. In a second step, exploiting differences in pH and polarity, it was possible to separate matrix components and THC-COOH, thereby yielding a clean elution of THC-COOH into the same collecting tube as THC and 11-OH-THC. Even when using a simple measuring technology like gas chromatography with single quadrupole mass spectrometry, this two-step elution allows for an obvious decrease in number and intensity of matrix interference in the chromatogram. Hence, in both plasma and serum, the AXS extracts resulted in very good selectivity. Limits of detection and limits of quantification were below 0.25 and 0.35 ng/mL for the neutral cannabinoids in both matrices, 2.0 and 3.0 ng/mL in plasma and 1.6 and 3.3 ng/mL in serum for THC-COOH. The recoveries were ≥79.8 % for all analytes. Interday and intraday imprecisions ranged from 0.8 to 6.1 % relative standard deviation, and accuracy bias ranged from -12.6 to 3.6 %.

  8. Quantitative mass spectrometry methods for pharmaceutical analysis.

    Science.gov (United States)

    Loos, Glenn; Van Schepdael, Ann; Cabooter, Deirdre

    2016-10-28

    Quantitative pharmaceutical analysis is nowadays frequently executed using mass spectrometry. Electrospray ionization coupled to a (hybrid) triple quadrupole mass spectrometer is generally used in combination with solid-phase extraction and liquid chromatography. Furthermore, isotopically labelled standards are often used to correct for ion suppression. The challenges in producing sensitive but reliable quantitative data depend on the instrumentation, sample preparation and hyphenated techniques. In this contribution, different approaches to enhance the ionization efficiencies using modified source geometries and improved ion guidance are provided. Furthermore, possibilities to minimize, assess and correct for matrix interferences caused by co-eluting substances are described. With the focus on pharmaceuticals in the environment and bioanalysis, different separation techniques, trends in liquid chromatography and sample preparation methods to minimize matrix effects and increase sensitivity are discussed. Although highly sensitive methods are generally aimed for to provide automated multi-residue analysis, (less sensitive) miniaturized set-ups have a great potential due to their ability for in-field usage.This article is part of the themed issue 'Quantitative mass spectrometry'. © 2016 The Author(s).

  9. Mass spectrometry for the characterisation of nanoparticles.

    Science.gov (United States)

    Montoro Bustos, Antonio R; Ruiz Encinar, Jorge; Sanz-Medel, Alfredo

    2013-07-01

    Mass spectrometry (MS) has gained much importance in recent years as a powerful tool for reliable analytical characterisation of nanoparticles (NPs). The outstanding capabilities of different MS-based techniques including elemental and molecular detection and their coupling with different separation techniques and mechanisms are outlined herein. Examples of highly valuable elemental and molecular information for a more complete characterisation of NPs are given. Some selected applications illustrate the analytical potential of MS for NP sizing and quantitative assessment of the size distribution as well.

  10. Deciphering Dorin M glycosylation by mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Man, Petr; Kovář, Vojtěch; Štěrba, Ján; Strohalm, Martin; Kavan, Daniel; Kopáček, Petr; Grubhoffer, Libor; Havlíček, Vladimír

    2008-01-01

    Roč. 14, č. 6 (2008), s. 345-354 ISSN 1469-0667 R&D Projects: GA MŠk LC545; GA MŠk(CZ) LC06009; GA ČR GD524/03/H133 Grant - others:CZ(CZ) SGA2008/017; XE(XE) EC MKTD-CT-2004-014407 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z60220518 Keywords : glycosylation * tandem mass spectrometry * lectin Subject RIV: EE - Microbiology, Virology Impact factor: 1.167, year: 2008

  11. Simultaneous mass detection for direct inlet mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, R.L.

    1979-05-01

    The evolution of analytical techniques for application in trace analysis has led to interest in practical methods for real-time monitoring. Direct inlet mass spectrometry (DIMS) has been the subject of considerable activity in recent years. A DIMS instrument is described which consists of an inlet system designed to permit particles entrained in the inlet air stream to strike a hot, oxidized rhenium filament which serves as a surface ionization source. A mass analyzer and detection system then permits identification of the elemental composition of particulates which strike the filament.

  12. Protein Sequencing with Tandem Mass Spectrometry

    Science.gov (United States)

    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.

  13. Study of odor recorder using Mass Spectrometry

    Science.gov (United States)

    Miura, Tomohiro; Nakamoto, Takamichi; Moriizumi, Toyosaka

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

  14. FAPA mass spectrometry of designer drugs.

    Science.gov (United States)

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

    2016-01-01

    Application of a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS) for the analysis of designer drugs is described. In this paper, we present application of FAPA MS for identification of exemplary psychotropic drugs: JWH-122, 4BMC, Pentedrone, 3,4-DNNC and ETH-CAT. We have utilized two approaches for introducing samples into the plasma stream; first in the form of a methanolic aerosol from the nebulizer, and the second based on a release of vapors from the electrically heated crucible by thermal desorption. The analytes were ionized by FAPA and identified in the mass analyzer. The order of release of the compounds depends on their volatility. These methods offer fast and reliable structural information, without pre-separation, and can be an alternative to the Electron Impact, GC/MS, and ESI for fast analysis of designer-, and other psychoactive drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Impact of automation on mass spectrometry.

    Science.gov (United States)

    Zhang, Yan Victoria; Rockwood, Alan

    2015-10-23

    Mass spectrometry coupled to liquid chromatography (LC-MS and LC-MS/MS) is an analytical technique that has rapidly grown in popularity in clinical practice. In contrast to traditional technology, mass spectrometry is superior in many respects including resolution, specificity, multiplex capability and has the ability to measure analytes in various matrices. Despite these advantages, LC-MS/MS remains high cost, labor intensive and has limited throughput. This specialized technology requires highly trained personnel and therefore has largely been limited to large institutions, academic organizations and reference laboratories. Advances in automation will be paramount to break through this bottleneck and increase its appeal for routine use. This article reviews these challenges, shares perspectives on essential features for LC-MS/MS total automation and proposes a step-wise and incremental approach to achieve total automation through reducing human intervention, increasing throughput and eventually integrating the LC-MS/MS system into the automated clinical laboratory operations. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Spatial Autocorrelation in Mass Spectrometry Imaging.

    Science.gov (United States)

    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

    2016-06-07

    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.

  17. Isotope ratio analysis by Orbitrap mass spectrometry

    Science.gov (United States)

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

    2016-12-01

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

  18. Ambient ionization mass spectrometry: A tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Min-Zong; Cheng, Sy-Chi; Cho, Yi-Tzu [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Shiea, Jentaie, E-mail: jetea@fac.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Cancer Center, Kaohsiung Medical University, Kaohsiung, Taiwan (China)

    2011-09-19

    Highlights: {yields} Ambient ionization technique allows the direct analysis of sample surfaces with little or no sample pretreatment. {yields} We sort ambient ionization techniques into three main analytical strategies, direct ionization, direct desorption/ionization, and two-step ionization. {yields} The underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques are described and compared. - Abstract: Ambient ionization is a set of mass spectrometric ionization techniques performed under ambient conditions that allows the direct analysis of sample surfaces with little or no sample pretreatment. Using combinations of different types of sample introduction systems and ionization methods, several novel techniques have been developed over the last few years with many applications (e.g., food safety screening; detection of pharmaceuticals and drug abuse; monitoring of environmental pollutants; detection of explosives for antiterrorism and forensics; characterization of biological compounds for proteomics and metabolomics; molecular imaging analysis; and monitoring chemical and biochemical reactions). Electrospray ionization and atmospheric pressure chemical ionization are the two main ionization principles most commonly used in ambient ionization mass spectrometry. This tutorial paper provides a review of the publications related to ambient ionization techniques. We describe and compare the underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques.

  19. NITPICK: peak identification for mass spectrometry data

    Directory of Open Access Journals (Sweden)

    Steen Hanno

    2008-08-01

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

  20. Field desorption mass spectrometry of oligosaccharides

    Science.gov (United States)

    Linscheid, Michael; D'Angona, Jay; Burlingame, Alma L.; Dell, Anne; Ballou, Clinton E.

    1981-01-01

    Field desorption mass spectrometry has been used to analyze carbohydrate polymers with 5 to 14 hexose units without prior derivatization. In all examples, the molecular weight of the oligosaccharide could be determined by means of the abundant quasimolecular ions of the type MNa+, MH+, MNa22+, and MNa33+. Fragmentation at glycosidic linkages was observed in varying extents. The reduced oligosaccharide Man8GlcNAcH2, obtained from IgM [Cohen, R. E. & Ballou, C. E. (1980) Biochemistry 19, 4345-4358], gave quasimolecular ion signals MNa+ at m/z 1544, MH+ at m/z 1522, MNa22+ at m/z 784, and MNa33+ at m/z 530, all corresponding to its assumed molecular weight of 1519.5. Mycobacterial methylmannose polysaccharides with the general structure ManxMeMany-OCH3 [Yamada, H., Cohen, R. E. & Ballou, C. E. (1979) J. Biol. Chem. 254, 1972-1979] were also successfully analyzed. Man1MeMan13-OCH3, the largest homolog, gave the expected signal of the quasimolecular ion MNa+ at m/z 2506. The larger polysaccharides were analyzed by using a KRATOS MS-50 mass spectrometer with a high-field magnet enabling full sensitivity to be maintained up to 3000 atomic mass units. Polysaccharides up to m/z 1978 were analyzed by using a KRATOS MS-9 mass spectrometer operated at 4 Kv. The signal-to-noise ratio, which becomes a serious problem in field desorption mass spectrometry at low accelerating voltages, and the low instrument sensitivity were improved considerably by our use of a method of adding scans with low total ion currents obtained over a longer desorption time. In this way, we obtained complete sequence information on methylmannose polysaccharides up to Man1MeMan9-OCH3(MNa+ at m/z 1802). Analysis of a presumed Man1MeMan7-OCH3, gave a spectrum consistent only with the structure Man2MeMan6-OCH3, revealing the existence of a methylmannose homolog with 2 unmethylated mannoses at the nonreducing end of the chain. PMID:6940169

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

    Science.gov (United States)

    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)

  2. [Application of mass spectrometry in mycology].

    Science.gov (United States)

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

    2016-06-01

    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) is becoming an essential tool in most microbiology laboratories. At present, by using a characteristic fungal profile obtained from whole cells or through simple extraction protocols, MALDI-TOF MS allows the identification of pathogenic fungi with a high performance potential. This methodology decreases the laboratory turnaround time, optimizing the detection of mycoses. This article describes the state-of-the-art of the use of MALDI-TOF MS for the detection of human clinical fungal pathogens in the laboratory and discusses the future applications of this technology, which will further improve routine mycological diagnosis. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  3. Detection of gunshot residues using mass spectrometry.

    Science.gov (United States)

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

    2014-01-01

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

  4. Capillary electrophoresis mass spectrometry based metabolomics

    Directory of Open Access Journals (Sweden)

    Alexander M. Buko

    2017-03-01

    Full Text Available Capillary electrophoresis–mass spectrometry (CE-MS is a powerful orthogonal technique capable of filling in gaps in the identification, quantitation and isomeric resolution of many small hydrophilic and charged metabolites. The metabolome is a large complex mixture of molecules for which not one technique nor a combination of techniques can optimally identify and measure it in it’s entirety. LC-MS, GC-MS and NMR have been the widely used for metabolomics for the past 20 years for a wide range of applications, each technique having shown uniqueness and advantages, for specific applications or target metabolic chemical space. CE-MS captures a unique metabolic chemical space beyond these standard methods providing another window into metabolomics profiling. This review will focus on the recent publications published within 2016 focusing on biotechnology and pharmaceutical applications of CE-MS.

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

    Science.gov (United States)

    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.

  6. Deciphering the histone code using mass spectrometry

    Science.gov (United States)

    Ueberheide, Beatrix M.; Mollah, Sahana

    2007-01-01

    During the past decade, studies surrounding chromatin research have grown exponentially. A major focus of chromatin biology is centered on understanding of how histone modifications alter chromatin structure at the molecular and mechanistic levels. Discoveries are being made at a rapid pace due to the advent of new and innovative techniques. Mass spectrometry has emerged as a powerful tool in the field of histone research due to its speed, sensitivity, and ease of use. This has resulted in the identification of a number of novel histone modification sites. In consequence, new roles in biological processes have been discovered and hypothetical models, such as the `histone code' have been reaffirmed or refined. One significant advantage to using mass spectrometric techniques is that the combinations of modifications on different sites can be determined which is crucial to deciphering the `histone code'. In this manuscript, the mass spectrometric approaches developed over the past decade for both qualitative and quantitative analysis of histone post-translational modifications (PTMs) are discussed.

  7. Attomole quantitation of protein separations with accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S; Grant, P G; Buccholz, B A; Dingley, K; Turteltaub, K W

    2000-12-15

    Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as 14C to sub-attomole sensitivity. We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5% . Micro-proton-induced-xray-emission quantifies elemental abundances in separated metalloprotein samples to nanogram amounts and is capable of quantifying phosphorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.

  8. Advantageous Uses of Mass Spectrometry for the Quantification of Proteins

    Directory of Open Access Journals (Sweden)

    John E. Hale

    2013-01-01

    Full Text Available Quantitative protein measurements by mass spectrometry have gained wide acceptance in research settings. However, clinical uptake of mass spectrometric protein assays has not followed suit. In part, this is due to the long-standing acceptance by regulatory agencies of immunological assays such as ELISA assays. In most cases, ELISAs provide highly accurate, sensitive, relatively inexpensive, and simple assays for many analytes. The barrier to acceptance of mass spectrometry in these situations will remain high. However, mass spectrometry provides solutions to certain protein measurements that are difficult, if not impossible, to accomplish by immunological methods. Cases where mass spectrometry can provide solutions to difficult assay development include distinguishing between very closely related protein species and monitoring biological and analytical variability due to sample handling and very high multiplexing capacity. This paper will highlight several examples where mass spectrometry has made certain protein measurements possible where immunological techniques have had a great difficulty.

  9. MALDI-TOF mass spectrometry in textile industry

    OpenAIRE

    Munteanu, Florentina-Daniela; Dinca, Nicolae; Paulo, Artur Cavaco

    2008-01-01

    In this paper are presented the possibilities of using matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry in textile industry. MALDI-TOF mass spectrometry it is a convenient, versatile method for characterization and identification of dyes and pigments, and also for characterization of fibers and contaminants of the fabrics.

  10. Identification of brassinosteroid signaling complexes by coimmunoprecipitation and mass spectrometry

    NARCIS (Netherlands)

    Dongen, van Walter; Heerde, van Luc; Boeren, Sjef; Vries, de Sacco C.

    2017-01-01

    A combination of coimmunoprecipitation (coIP) of tagged proteins followed by protein identification and quantitation using Liquid Chromatography Mass Spectrometry/Mass Spectrometry (LCMS/MS) has proven to be a reliable method to qualitatively characterize membrane-bound receptor complexes from

  11. Probing the Composition, Assembly and Activity of Protein Molecular Machines using Native Mass Spectrometry

    NARCIS (Netherlands)

    Waterbeemd, M.J. van de

    2017-01-01

    Native mass spectrometry and mass spectrometry in general, are powerful analytical tools for studying proteins and protein complexes. Native mass spectrometry may provide accurate mass measurements of large macromolecular assemblies enabling the investigation of their composition and stoichiometry.

  12. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Matthew George [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adamic, Mary Louise [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, John Eric [Idaho National Lab. (INL), Idaho Falls, ID (United States); Baeck, D. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fox, R. V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hahn, P. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jenson, D. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lister, T. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    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

  13. Development of lithium attachment mass spectrometry - knudsen effusion and chemical ionisation mass spectrometry (KEMS, CIMS).

    Science.gov (United States)

    Booth, A Murray; Bannan, Thomas J; Benyezzar, Med; Bacak, Asan; Alfarra, M Rami; Topping, David; Percival, Carl J

    2017-10-07

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting, sensitive and robust method for the detection of volatile species in the gas phase. The design, manufacture and results of lithium based ion attachment ionisation sources for two different mass spectrometry systems are presented. In this study trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure measurements are made using a modified Knudsen Effusion Mass Spectrometer (KEMS). In the Li+ CIMS, where the Li+ ionization acts a soft and unselective ionization source, limits of detection of 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt for ammonia were achieved, allowing for ambient measurements of such species at atmospherically relevant concentrations. In the first application of Lithium ion attachment in ultra-high vacuum (UHV), vapor pressures of various atmospherically relevant species were measured with the adapted KEMS, giving measured values equivalent to previous results from electron impact KEMS. In the Li+ KEMS vapour pressures <10-3 mbar can be measured without any fragmentation, as is seen with the initial electron impact (EI) set up, allowing the vapor pressure of individual components within mixtures to be determined.

  14. Mass spectrometry innovations in drug discovery and development.

    Science.gov (United States)

    Papac, D I; Shahrokh, Z

    2001-02-01

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

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

    Science.gov (United States)

    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…

  16. Electrospray ionization mass spectrometry of metalloporphyrins.

    Science.gov (United States)

    Vandell, V E; Limbach, P A

    1998-03-01

    The magnesium, nickel, copper, zinc and vanadium metalloporphyrins from octaethylporphyrin, etioporphyrin I and tetraphenylporphyrin were characterized using electrospray ionization mass spectrometry (ESI-MS). The ion abundance of each of the porphyrins present in binary mixtures was monitored as a function of the porphyrin concentration and is dependent on the metalloporphyrin oxidation potential. It was found that, for binary mixtures of metalloporphyrins whose oxidation potentials differ by less than 0.1 V, the resulting ion abundance of each species is directly proportional to the concentration of each analyte in the mixture. For binary mixtures whose oxidation potentials differ by more than 0.1 V, relative abundances of the radical cations of each metalloporphyrin are determined by the oxidation potential and concentration of each metalloporphyrin with the analyte of lowest oxidation potential being ionized preferentially. The ability to ionize selectively one porphyrin over another in a binary mixture offers the potential to use ESI-MS for the qualitative analysis of porphyrins present in complex mixtures.

  17. Detection of Gunshot Residues Using Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Regina Verena Taudte

    2014-01-01

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

  18. Applications of graphene in mass spectrometry.

    Science.gov (United States)

    Kong, Xianglei; Huang, Yi

    2014-07-01

    This paper reviews the up-to-date research about the applications of graphene and its related materials in the field of mass spectrometry (MS). Due to its large surface area, delocalized pi-electrons, thermal conductivity, stability and rich interaction chemistry, graphene has been widely used in MS-based analytical chemistry. Graphene-based materials were applied as very effective matrixes or surfaces for many kinds of organic molecules in laser desorption/ionization (LDI) MS analysis. Many advantages of this novel matrix have been proved, which included: low interference ions from matrix itself, good reproducibility, high salt tolerance and so on. The unique properties of graphene also make it a superior sorbent used in solid-phase extraction (SPE). Further development of online SPE methods based on graphene coupling directly with LDI-MS, GC-MS and LC-MS greatly simplifies the MS-based analytical procedure for complex samples and makes the corresponding high-throughput and automatic analysis performable. Their applications as a platform in proteolysis for the rapid identification of proteins have been also developed. In addition, graphene was found to be a unique precursor for the generation of large-sized carbon cluster anions in the gas phase. Finally, the possible challenges and future perspectives in their applications in MS are discussed too.

  19. Charging of Proteins in Native Mass Spectrometry

    Science.gov (United States)

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

    2017-02-01

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

  20. Correcting mass shifts: A lock mass-free recalibration procedure for mass spectrometry imaging data

    Czech Academy of Sciences Publication Activity Database

    Kulkarni, P.; Kaftan, F.; Kynast, P.; Svatoš, Aleš; Böcker, S.

    2015-01-01

    Roč. 407, č. 25 (2015), s. 7603-7613 ISSN 1618-2642 Institutional support: RVO:61388963 Keywords : mass spectrometry imaging * recalibration * mass shift correction * data processing Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.125, year: 2015

  1. Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2015-01-01

    The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often ...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

  2. Determination of thermodynamic and kinetic properties of biomolecules by mass spectrometry.

    Science.gov (United States)

    Gülbakan, Basri; Barylyuk, Konstantin; Zenobi, Renato

    2015-02-01

    Over the past two decades, mass spectrometry (MS) has transformed the life sciences. The advances in understanding biomolecule structure and function by MS is progressing at an accelerated pace. MS has also largely been applied to study thermodynamic and kinetic structure of biomolecules. Herein, we highlight the recent discussions about native mass spectrometry and studies about determining stable gas phase structures, hydrogen/deuterium exchange studies about reaction kinetics and determination of binding constants of biomolecules with their ligands. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Simple setup for gas-phase h/d exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale

    DEFF Research Database (Denmark)

    Mistarz, Ulrik Hvid; Brown, Jeffery M; Haselmann, Kim F

    2014-01-01

    with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility......Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX...... gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3...

  4. Understanding ligand effects in gold clusters using mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Laskin, Julia

    2016-01-01

    This review summarizes recent research on the influence of phosphine ligands on the size, stability, and reactivity of gold clusters synthesized in solution. Sub-nanometer clusters exhibit size- and composition-dependent properties that are unique from those of larger nanoparticles. The highly tunable properties of clusters and their high surface-to-volume ratio make them promising candidates for a variety of technological applications. However, because “each-atom-counts” toward defining cluster properties it is critically important to develop robust synthesis methods to efficiently prepare clusters of predetermined size. For decades phosphines have been known to direct the size-selected synthesis of gold clusters. Despite the preparation of numerous species it is still not understood how different functional groups at phosphine centers affect the size and properties of gold clusters. Using electrospray ionization mass spectrometry (ESI-MS) it is possible to characterize the effect of ligand substitution on the distribution of clusters formed in solution at defined reaction conditions. In addition, ligand exchange reactions on preformed clusters may be monitored using ESI-MS. Collision induced dissociation (CID) may also be employed to obtain qualitative insight into the fragmentation of mixed ligand clusters and the relative binding energies of differently substituted phosphines. Quantitative ligand binding energies and cluster stability may be determined employing surface induced dissociation (SID) in a custom-built Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS). Rice-Ramsperger-Kassel-Marcus (RRKM) based modeling of the SID data allows dissociation energies and entropy values to be extracted that may be compared with the results of high-level theoretical calculations. The charge reduction and reactivity of atomically precise gold clusters, including partially ligated species generated in the gas-phase by in source CID, on well

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

    Science.gov (United States)

    Johnson, Grant E; Laskin, Julia

    2016-06-21

    This review summarizes recent research on the influence of phosphine ligands on the size, stability, and reactivity of gold clusters synthesized in solution. Sub-nanometer clusters exhibit size- and composition-dependent properties that are unique from those of larger nanoparticles. The highly tunable properties of clusters and their high surface-to-volume ratio make them promising candidates for a variety of technological applications. However, because "each-atom-counts" toward defining cluster properties it is critically important to develop robust synthesis methods to efficiently prepare clusters of predetermined size. For decades phosphines have been known to direct the size-selected synthesis of gold clusters. Despite the preparation of numerous species it is still not understood how different functional groups at phosphine centers affect the size and properties of gold clusters. Using electrospray ionization mass spectrometry (ESI-MS) it is possible to characterize the effect of ligand substitution on the distribution of clusters formed in solution at defined reaction conditions. In addition, ligand exchange reactions on preformed clusters may be monitored using ESI-MS. Collision induced dissociation (CID) may also be employed to obtain qualitative insight into the fragmentation of mixed ligand clusters and the relative binding energies of differently substituted phosphines. Quantitative ligand binding energies and cluster stability may be determined employing surface induced dissociation (SID) in a custom-built Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS). Rice-Ramsperger-Kassel-Marcus (RRKM) based modeling of the SID data allows dissociation energies and entropy values to be extracted. The charge reduction and reactivity of atomically precise gold clusters, including partially ligated species generated in the gas-phase by in source CID, on well-defined surfaces may be explored using ion soft landing (SL) in a custom

  6. The diverse and expanding role of mass spectrometry in structural and molecular biology.

    Science.gov (United States)

    Lössl, Philip; van de Waterbeemd, Michiel; Heck, Albert Jr

    2016-12-15

    The emergence of proteomics has led to major technological advances in mass spectrometry (MS). These advancements not only benefitted MS-based high-throughput proteomics but also increased the impact of mass spectrometry on the field of structural and molecular biology. Here, we review how state-of-the-art MS methods, including native MS, top-down protein sequencing, cross-linking-MS, and hydrogen-deuterium exchange-MS, nowadays enable the characterization of biomolecular structures, functions, and interactions. In particular, we focus on the role of mass spectrometry in integrated structural and molecular biology investigations of biological macromolecular complexes and cellular machineries, highlighting work on CRISPR-Cas systems and eukaryotic transcription complexes. © 2016 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

  7. Large-Scale Identification of the Arginine Methylome by Mass Spectrometry

    DEFF Research Database (Denmark)

    Sylvestersen, Kathrine B; Nielsen, Michael L

    2015-01-01

    The attachment of one or more methylation groups to the side chain of arginine residues is a regulatory mechanism for cellular proteins. Recent advances in mass spectrometry-based characterization allow comprehensive identification of arginine methylation sites by peptide-level enrichment...... strategies. Described in this unit is a 4-day protocol for enrichment of arginine-methylated peptides and subsequent identification of thousands of distinct sites by mass spectrometry. Specifically, the protocol explains step-by-step sample preparation, enrichment using commercially available antibodies......, prefractionation using strong cation exchange, and identification using liquid chromatography coupled to tandem mass spectrometry. A strategy for relative quantification is described using stable isotope labeling by amino acids in cell culture (SILAC). Approaches for analysis of arginine methylation site occupancy...

  8. DETECTION OF MYCOTOXINS USING MALDI-TOF MASS SPECTROMETRY

    National Research Council Canada - National Science Library

    Lukáš Hleba; Miroslava Císarová; Mohammad Ali Shariati; Dana Tančinová

    2017-01-01

    .... In this study, a six mycotoxins, concretely: aflatoxin B1, citrinin, deoxynivalenol, zearalenone, T2-toxin, and griseofulvin were detected by Matrix Assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry (MALDI-TOF MS...

  9. Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry

    National Research Council Canada - National Science Library

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

    2013-01-01

    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...

  10. Targeting synaptic pathology with a novel affinity mass spectrometry approach

    National Research Council Canada - National Science Library

    Brinkmalm, Ann; Brinkmalm, Gunnar; Honer, William G; Moreno, Julie A; Jakobsson, Joel; Mallucci, Giovanna R; Zetterberg, Henrik; Blennow, Kaj; Öhrfelt, Annika

    2014-01-01

    .... This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function...

  11. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    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.

  12. Confirmatory assay for ivermectin in cattle tissue using chemical ionization mass spectrometry/mass spectrometry (MS/MS).

    Science.gov (United States)

    Tway, P C; Downing, G V; Slayback, J R; Rahn, G S; Isensee, R K

    1984-04-01

    A method based on direct exposure, positive ion, chemical ionization mass spectrometry/mass spectrometry (ms/ms) was developed for the confirmatory assay of the antiparasitic drug, ivermectin, in animal tissue. Following extraction, column and preparative liquid chromatography, mass spectrometric/mass spectrometric analysis of the drug in liver samples provided reliable detection limits to 8-10 parts-per-billion at a signal: noise of greater than 10:1. Blank tissue consistently displayed no chemical/matrix interference. Besides the development of a confirmatory assay, the study also demonstrates the analytical capability and the role of MS/MS vis-a-vis other applied mass spectrometric techniques.

  13. Analysis of posttranslational modifications of proteins by tandem mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Trelle, Morten B; Thingholm, Tine E

    2006-01-01

    -temporal distribution in cells and tissues. Most PTMs can be detected by protein and peptide analysis by mass spectrometry (MS), either as a mass increment or a mass deficit relative to the nascent unmodified protein. Tandem mass spectrometry (MS/MS) provides a series of analytical features that are highly useful...... for the characterization of modified proteins via amino acid sequencing and specific detection of posttranslationally modified amino acid residues. Large-scale, quantitative analysis of proteins by MS/MS is beginning to reveal novel patterns and functions of PTMs in cellular signaling networks and biomolecular structures....

  14. The allure of mass spectrometry: From an earlyday chemist's perspective

    Science.gov (United States)

    2016-01-01

    1 This reminiscing review article is an account of the author's fascination and involvements with mass spectrometry from the perspective of an organic chemist with an interest in natural product chemistry. It covers a period from 1961 through the mid 1990s as mass spectrometry evolved form a novelty technique to become a most widely used analytical technique. Following a brief synopsis of my pathway to mass spectrometry, my research efforts in this field are presented with a focus mainly on evolving principles and technologies which I had personal involvements with. To provide historical perspectives, discussions of these developments are accompanied by brief outlines of the relevant state‐of‐the‐art, shedding light on the technical and conceptual challenges encountered during those early days in mass spectrometry. Examples are presented of my involvements with basic and applied research in mass spectrometry during graduate studies at Stanford University and close to three decade tenure in pharmaceutical research at Syntex Research. My basic research interests focused mainly on principles of electron ionization induced fragmentation mechanisms, with an emphasis on steroids and other model compounds. Extensive deuterium labeling evidence was used to determine the fragmentation mechanisms of the diagnostically significant ions in the spectra of numerous model compounds, uncovering examples of wide‐ranging hydrogen transfers, skeletal rearrangements, methyl and phenyl migrations, stereoselective fragmentations and low and high energy fragmentation processes. Depiction of the industrial research phase of my career includes comments on the pivotal role mass spectrometry played on advancing modern pharmaceutical research. Examples are presented of involvements with instrumental developments and a few select cases of applied research, including studies of bile mechanisms in vertebrates, identification of bisphenol‐A leaching from sterilized polycarbonate

  15. Injection optics for fast mass switching for accelerator mass spectrometry

    Science.gov (United States)

    Weisser, D. C.; Fifield, L. K.; De Cesare, M.; Tims, S. G.; Lobanov, N. R.; Crook, G. G.; Tsifakis, D.; Tunningley, T. B.

    2013-04-01

    Accelerator Mass Spectrometry (AMS) measures the ratio of extremely small amounts of a radioactive isotope in the presence of ˜ 1015 times more stable ones. The isotopes are injected sequentially over a repeated period and observed at the exit of the accelerator. so any fluctuations in ion source output or transmission through the accelerator over a time comparable to the measurement time, will reduce the accuracy of such measurements. This compromise in accuracy can be lessened by reducing the switching time between isotopes from several seconds to a few milli-seconds. New AMS systems accomplish fast switching by modifying the beam energy though the 90 injection magnet by pulsing the voltage by several kV on the flight tube in the magnet. That requires that the flight tube be electrically insulated which competes with having the flight tube as large as possible. At the ANU, insulating the magnet flight tube would not only have reduced the acceptance of the injection system, but conflicted with a beam chopper attached to the flight tube, that would also have had to be insulated from the ground. This was not practical so the novel alternative of pulsing the voltage on the high voltage ion source deck is being implemented. Beam optics calculations have been performed and beam tests conducted that demonstrated that, in addition to pulsing the voltage on the 150 kV ion source deck, a pulsed Einzel lens in front of the following electrostatic quadrupole triplet lens is required to maintain isotope-independent transmission through the 14UD Pelletron accelerator. The high voltage rise time performance of the components of the system has been shown to be satisfactory.

  16. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery

    Directory of Open Access Journals (Sweden)

    Ming Lu

    2007-01-01

    Full Text Available Proteomics is a rapidly advancing field not only in the field of biology but also in translational cancer research. In recent years, mass spectrometry and associated technologies have been explored to identify proteins or a set of proteins specific to a given disease, for the purpose of disease detection and diagnosis. Such biomarkers are being investigated in samples including cells, tissues, serum/plasma, and other types of body fluids. When sufficiently refined, proteomic technologies may pave the way for early detection of cancer or individualized therapy for cancer. Mass spectrometry approaches coupled with bioinformatic tools are being developed for biomarker discovery and validation. Understanding basic concepts and application of such technology by investigators in the field may accelerate the clinical application of protein biomarkers in disease management.Abbreviations: 2DE: two-dimensional gel electrophoresis; ABPP: activity-based protein profiling; CEA: carcinoembryonic antigen; CI: confidence interval; ESI: electrospray ionization; FP: fluorophosphonate; HPLC: high performance liquid chromatography; ICAT: isotope coded affi nitytags; IEF: isoelectric focusing; iTRAQ: isobaric tags for relative and absolute quantification; LCMS: combined liquid chromatography-mass spectrometry; LCMSMS: liquid chromatography tandem mass spectrometry; LOD: limit of detection; m/z: mass to charge ratio; MALDI: matrix-assisted laser desorption ionization; MS: mass spectrometry; MUDPIT: multidimensional protein identification technology; NAF: nipple aspirate fluid; PMF: peptide mass fingerprinting; PSA: prostate specifi c antigen; PTMs: post-translational modifications; RPMA: reverse phase protein microarray; SELDI: surface enhanced laser desorption ionization; TOF: time-of-flight.

  17. Matrix-assisted laser desorption/ionisation mass spectrometry of transfer ribonucleic acids isolated from yeast.

    Science.gov (United States)

    Gruic-Sovulj, I; Lüdemann, H C; Hillenkamp, F; Weygand-Durasevic, I; Kucan, Z; Peter-Katalinic, J

    1997-01-01

    tRNATyr and tRNASer purified from bulk brewer's yeast tRNA were subjected to analysis by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. Choosing a mixture of 2,4,6- and 2,3,4-trihydroxy-acetophenone and diammonium citrate as matrix a mass resolution of up to 220 (FWHM) was achieved in the linear mode of operation. Cation adduct suppression by addition of cation exchange beads and a chelating agent (CDTA) is shown to substantially improve mass resolution for this class of molecules. PMID:9108172

  18. Penning-trap mass spectrometry and neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, Sergey; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Novikov, Yuri N. [Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Department of Physics, St. Petersburg State University (Russian Federation)

    2013-09-15

    Rapidly developing neutrino physics has found in Penning-trap mass spectrometry a staunch ally in investigating a variety of fundamental problems. The most familiar are the absolute neutrino mass, possible existence of resonant neutrinoless double-electron capture and of keV-sterile neutrinos, and investigation of neutrino oscillations. This article is a brief review of the latest achievements and future perspectives of Penning-trap mass spectrometry in the exploration of these problems with a focus on electron capture and double electron capture processes. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. AM1 and electron impact mass spectrometry study of the ...

    African Journals Online (AJOL)

    Recently, in electron impact mass spectrometry (EIMS), it has been found a good correlation between the fragmentation processes of coumarins and the electronic charges of the atoms of their skeleton. In this paper, the same analytical method has been applied to 4-acyl isochroman-1,3-diones, whose mass spectra had ...

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

    Science.gov (United States)

    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. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)

    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.

  2. Development of stereotactic mass spectrometry for brain tumor surgery.

    Science.gov (United States)

    Agar, Nathalie Y R; Golby, Alexandra J; Ligon, Keith L; Norton, Isaiah; Mohan, Vandana; Wiseman, Justin M; Tannenbaum, Allen; Jolesz, Ferenc A

    2011-02-01

    Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue. To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents. Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity. Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence. The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of

  3. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin

    Science.gov (United States)

    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.

  4. Breaking the histone code with quantitative mass spectrometry.

    Science.gov (United States)

    Britton, Laura-Mae P; Gonzales-Cope, Michelle; Zee, Barry M; Garcia, Benjamin A

    2011-10-01

    Histone post-translational modifications (PTMs) comprise one of the most intricate nuclear signaling networks that govern gene expression in a long-term and dynamic fashion. These PTMs are considered to be 'epigenetic' or heritable from one cell generation to the next and help establish genomic expression patterns. While much of the analyses of histones have historically been performed using site-specific antibodies, these methods are replete with technical obstacles (i.e., cross-reactivity and epitope occlusion). Mass spectrometry-based proteomics has begun to play a significant role in the interrogation of histone PTMs, revealing many new aspects of these modifications that cannot be easily determined with standard biological approaches. Here, we review the accomplishments of mass spectrometry in the histone field, and outline the future roadblocks that must be overcome for mass spectrometry-based proteomics to become the method of choice for chromatin biologists.

  5. Analysis of oxysterols by electrospray tandem mass spectrometry.

    Science.gov (United States)

    Griffiths, William J; Wang, Yuqin; Alvelius, Gunvor; Liu, Suya; Bodin, Karl; Sjövall, Jan

    2006-03-01

    Oxysterols are oxygenated derivatives of cholesterol. They are intermediates in cholesterol excretion pathways and may also be regarded as transport forms of cholesterol. The introduction of additional hydroxyl groups to the cholesterol skeleton facilitates the flux of oxysterols across the blood brain barrier, and oxysterols have been implicated in mediating a number of cholesterol-induced metabolic effects. Oxysterols are difficult to analyze by atmospheric pressure ionization mass spectrometry on account of the absence of basic or acidic functional groups in their structures. In this communication, we report a method for the derivatization and analysis of oxysterols by electrospray mass spectrometry. Oxysterols with a 3beta-hydroxy-Delta5 structure were converted by cholesterol oxidase to 3-oxo-Delta4 steroids and then derivatized with the Girard P reagent to give Girard P hydrazones, which were subsequently analyzed by tandem mass spectrometry. The improvement in sensitivity for the analysis of 25-hydroxycholesterol upon oxidation and derivatization was over 1000.

  6. Sample preparation in biological mass spectrometry

    CERN Document Server

    Ivanov, Alexander R

    2011-01-01

    The aim of this book is to provide the researcher with important sample preparation strategies in a wide variety of analyte molecules, specimens, methods, and biological applications requiring mass spectrometric analysis as a detection end-point.

  7. Major roles for minor bacterial lipids identified by mass spectrometry.

    Science.gov (United States)

    Garrett, Teresa A

    2017-11-01

    Mass spectrometry of lipids, especially those isolated from bacteria, has ballooned over the past two decades, affirming in the process the complexity of the lipidome. With this has come the identification of new and interesting lipid structures. Here is an overview of several novel lipids, from both Gram-negative and Gram-positive bacteria with roles in health and disease, whose structural identification was facilitated using mass spectrometry. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Schottky mass- and lifetime-spectrometry of unstable, stored ions

    CERN Document Server

    Bosch, F

    2003-01-01

    GSI is presently the only facility where unstable, highly charged ions far from stability can be produced by in-flight fragmentation and subsequently stored and cooled in an ion storage ring. The mass-to-charge ratio of those stored ions is measured by two complementary methods that have been developed at GSI: Schottky mass-spectrometry, based on the recording of the revolution frequencies of electron-cooled ions, and isochronous mass-spectrometry, applied on short-lived, uncooled ions at the 'transition energy'. Both methods provide a highly efficient, precise and sensitive determination of the nuclear mass of many simultaneously stored ion species. Similarly, the beta lifetimes of stored, unstable nuclei can also be determined. The impact of nuclear masses and lifetimes for both nuclear physics and astrophysics is also addressed.

  9. Structure Determination of Natural Products by Mass Spectrometry

    Science.gov (United States)

    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.

  10. Elucidating rhizosphere processes by mass spectrometry – A review

    Energy Technology Data Exchange (ETDEWEB)

    Rugova, Ariana [Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria); Puschenreiter, Markus [Department of Forest and Soil Sciences, Rhizosphere Ecology and Biogeochemistry Group, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria); Koellensperger, Gunda [Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Vienna (Austria); Hann, Stephan, E-mail: stephan.hann@boku.ac.at [Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences-BOKU, Vienna (Austria)

    2017-03-01

    The presented review discusses state-of-the-art mass spectrometric methods, which have been developed and applied for investigation of chemical processes in the soil-root interface, the so-called rhizosphere. Rhizosphere soil's physical and chemical characteristics are to a great extent influenced by a complex mixture of compounds released from plant roots, i.e. root exudates, which have a high impact on nutrient and trace element dynamics in the soil-root interface as well as on microbial activities or soil physico-chemical characteristics. Chemical characterization as well as accurate quantification of the compounds present in the rhizosphere is a major prerequisite for a better understanding of rhizosphere processes and requires the development and application of advanced sampling procedures in combination with highly selective and sensitive analytical techniques. During the last years, targeted and non-targeted mass spectrometry-based methods have emerged and their combination with specific separation methods for various elements and compounds of a wide polarity range have been successfully applied in several studies. With this review we critically discuss the work that has been conducted within the last decade in the context of rhizosphere research and elemental or molecular mass spectrometry emphasizing different separation techniques as GC, LC and CE. Moreover, selected applications such as metal detoxification or nutrient acquisition will be discussed regarding the mass spectrometric techniques applied in studies of root exudates in plant-bacteria interactions. Additionally, a more recent isotope probing technique as novel mass spectrometry based application is highlighted. - Highlights: • State-of-the-art mass spectrometry methods developed and applied in rhizosphere research are reviewed. • Elemental and molecular mass spectrometry emphasizing different separation techniques (GC, LC or CE) are discussed. • Case studies on metal detoxification

  11. Mass Spectrometry-Based Diagnosis of Hemoglobinopathies: A Potential Tool for the Screening of Genetic Disorder.

    Science.gov (United States)

    Das, Rajdeep; Mitra, Gopa; Mathew, Boby; Bhat, Vijay; Ross, Cecil; Pal, Debnath; Mandal, Amit Kumar

    2016-12-01

    Hemoglobinopathies are caused by point mutation in globin gene that results in structural variant of hemoglobin. While 7 % of world populations are carrier of hemoglobinopathies, the prevalence of the disease varies between 3 to 17 % across different population groups in India. In a diagnostic laboratory, alkaline gel electrophoresis and cation exchange-based HPLC (CE-HPLC) are most widely used techniques for characterization of hemoglobin variants. In the above methods, the differential surface charge of hemoglobin molecule in variants is exploited for their characterization. Sometime, co-migration of variants in gel electrophoresis and co-elution or elution with unknown retention time in automated CE-HPLC might lead to ambiguity in the analysis of hemoglobinopathies. Under such circumstances, it is necessary to use other analytical methods that provide unambiguous results. Mass spectrometry-based proteomics approach and DNA sequence analysis are examples of such alternative methods. In the present study, liquid chromatography coupled to mass spectrometry has been used for three commonly observed variants in India, e.g., HbE, HbQ India and HbD Punjab that appeared with inappropriate results in the conventional analysis. A customized hemoglobin variant database has been used in the mass spectrometry-based analysis of those three variants. Mass spectrometry-based proteomics approach was used to analyze above variant sample accurately.

  12. The analysis of aqueous mixtures using liquid chromatography-electrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Steven [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions. The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivatization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process. This report contains a general introduction to the project and the general conclusions. Four chapters have been removed for separate processing. Titles are: Chapter 2: Determination of small carboxylic acids by ion exclusion chromatography with electrospray mass spectrometry; Chapter 3: Electrochemical incineration of benzoquinone in aqueous media using a quaternary metal oxide electrode in the absence of a soluble supporting electrolyte; Chapter 4: The determination of electrochemical incineration products of 4-chlorophenol by liquid chromatography-electrospray mass spectrometry; and Chapter 5: Determination of small carboxylic acids by capillary electrophoresis with electrospray mass spectrometry.

  13. Mass spectrometry of pertrimethylsilyl aldosyl oligosaccharides

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Kamerling, J.P.; Vink, Jan; Ridder, J.J. de

    1971-01-01

    The mass spectra of 18 trimethylsilyl disaccharides containing only aldohexoses, connected via all possible linkages (1 -> 1) to (1 -> 6), were compared. These spectra could be divided into three main groups: (1 -> 1) disaccharides, (1 -> 2), (1 -> 3), (1 -> 4) disaccharides and (1 -> 5), (1 -> 6)

  14. Characterizing the lipid and metabolite changes associated with placental function and pregnancy complications using ion mobility spectrometry-mass spectrometry and mass spectrometry imaging

    Energy Technology Data Exchange (ETDEWEB)

    Burnum-Johnson, Kristin E.; Baker, Erin S.; Metz, Thomas O.

    2017-12-01

    Successful pregnancy is dependent upon discrete biological events, which include embryo implantation, decidualization, and placentation. Problems associated with each of these events can cause infertility or conditions such as preeclampsia. A greater understanding of the molecular changes associated with these complex processes is necessary to aid in identifying treatments for each condition. Previous nuclear magnetic resonance spectroscopy and mass spectrometry studies have been used to identify metabolites and lipids associated with pregnancy-related complications. However, due to limitations associated with conventional implementations of both techniques, novel technology developments are needed to more fully understand the initiation and development of pregnancy related problems at the molecular level. In this perspective, we describe current analytical techniques for metabolomic and lipidomic characterization of pregnancy complications and discuss the potential for new technologies such as ion mobility spectrometry-mass spectrometry and mass spectrometry imaging to contribute to a better understanding of the molecular changes that affect the placenta and pregnancy outcomes.

  15. LC-Mass Spectrometry for Metabolomics.

    Science.gov (United States)

    Dailey, Allyson L

    2017-01-01

    The field of metabolomics is greatly being refined by the addition of new technologies. LC-MS has allowed researchers to explore additional metabolites which were not originally captured through GC-MS. Through the customizability of the LC columns and mass spectrometer, it is now easier to tailor the instrument to your research needs. Herein, we describe a protocol for sample preparation and data acquisition for a global metabolomic analysis of tissues or feces.

  16. Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Gerssen, A.; McElhinney, A. M.; Mulder, P.P.J.; Bire, L.; Hess, P.; de Boer, J.

    2009-01-01

    The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

  17. Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Gerssen, A.; McElhinney, M.; Mulder, P.P.J.; Bire, R.; Hess, P.; Boer, de J.

    2009-01-01

    The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC¿MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

  18. Absorption Mode FT-ICR Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. High-accuracy mass spectrometry for fundamental studies.

    Science.gov (United States)

    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.

  20. Post-translational modifications and mass spectrometry detection.

    Science.gov (United States)

    Silva, André M N; Vitorino, Rui; Domingues, M Rosário M; Spickett, Corinne M; Domingues, Pedro

    2013-12-01

    In this review, we provide a comprehensive bibliographic overview of the role of mass spectrometry and the recent technical developments in the detection of post-translational modifications (PTMs). We briefly describe the principles of mass spectrometry for detecting PTMs and the protein and peptide enrichment strategies for PTM analysis, including phosphorylation, acetylation and oxidation. This review presents a bibliographic overview of the scientific achievements and the recent technical development in the detection of PTMs is provided. In order to ascertain the state of the art in mass spectrometry and proteomics methodologies for the study of PTMs, we analyzed all the PTM data introduced in the Universal Protein Resource (UniProt) and the literature published in the last three years. The evolution of curated data in UniProt for proteins annotated as being post-translationally modified is also analyzed. Additionally, we have undertaken a careful analysis of the research articles published in the years 2010 to 2012 reporting the detection of PTMs in biological samples by mass spectrometry. © 2013 Elsevier Inc. All rights reserved.

  1. Liquid Chromatography – Mass Spectrometry Method for the ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple and selective high performance liquid chromatography photo diode array mass spectrometry (HPLC-PDA-MS/MS) method for simultaneous determination and confirmation of seven major active alkaloids (6-Hydroxy-ß-Carboline-1-carboxylic acid, ß-Carboline-1- carboxylic acid, ...

  2. MICELLAR ELECTROKINETIC CHROMATOGRAPHY-MASS SPECTROMETRY (R823292)

    Science.gov (United States)

    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...

  3. Fast atom bombardment mass spectrometry of condensed tannin sulfonate derivatives

    Science.gov (United States)

    J.J. Karchesy; L.Y. Foo; Richard W. Hemingway; E. Barofsky; D.F. Barofsky

    1989-01-01

    Condensed tannin sulfonate derivatives were studied by fast atom bombardment mass spectrometry (FAB-MS) to assess the feasibility of using this technique for determining molecular weight and structural information about these compounds. Both positive- and negative-ion spectra provided useful data with regard to molecular weight, cation species present, and presence of...

  4. On-Line Synthesis and Analysis by Mass Spectrometry

    Science.gov (United States)

    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…

  5. Oxidative protein labeling in mass-spectrometry-based proteomics

    NARCIS (Netherlands)

    Roeser, Julien; Bischoff, Rainer; Bruins, Andries P.; Permentier, Hjalmar P.

    Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label

  6. Advances in mass spectrometry driven O-glycoproteomics

    DEFF Research Database (Denmark)

    Levery, Steven B; Steentoft, Catharina; Halim, Adnan

    2015-01-01

    BACKGROUND: Global analyses of proteins and their modifications by mass spectrometry are essential tools in cell biology and biomedical research. Analyses of glycoproteins represent particular challenges and we are only at the beginnings of the glycoproteomic era. Some of the challenges have been...

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

    Science.gov (United States)

    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)

  8. Analysis of essential oils by gas chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Y.

    1976-01-01

    The book is in two parts: first part Essential Oil includes compositae; labiatae; verbenaceae; oleaceae; umbelliferae; myrtaceae; euphorbiaceae; rutaceae; geraniaceae; rosaceae; lauraceae; myristicaceae; anonaceae; santalaceae; moraceae; piperaceae; zingiberaceae; araceae; gramineae; and cupressaceae written in English and Japanese. Part two includes essential oil; gas chromatography, and mass spectrometry written in Japanese. (DP)

  9. Negative ion-atmospheric pressure photoionization-mass spectrometry

    NARCIS (Netherlands)

    Kauppila, T.J.; Kotiaho, T.; Kostiainen, R; Bruins, A.P.

    The ionization mechanism in the novel atmospheric pressure photoionization mass spectrometry (APPI-MS) in negative ion mode was studied thoroughly by the analysis of seven compounds in 17 solvent systems. The compounds possessed either gas-phase acidity or positive electron affinity, whereas the

  10. Detection of biomedically relevant stilbenes from wines by mass spectrometry.

    Science.gov (United States)

    Andrei, Veronica; Ngounou Wetie, Armand G; Mihai, Iuliana; Darie, Costel C; Vasilescu, Alina

    2014-01-01

    Stilbenes represent a class of compounds with a common 1,2-diphenylethylene backbone that have shown extraordinary potential in the biomedical field. As the most well-known example, resveratrol proved to have anti-aging effects and significant potential in the fight against cardiovascular diseases and some types of cancer. Mass spectrometry is an analytical method of critical importance in all studies related to stilbenes that are important in the biomedical field. From the discovery of new natural compounds and mapping the grape metabolome up to advanced investigations of stilbenes' potential for the protection of human health in clinical studies, mass spectrometry has provided critical analytical information. In this review we focus on various approaches related to mass spectrometry for the detection of stilbenes-such as coupling with chromatographic separation methods and direct infusion-with presentation of some illustrative applications. Clearly, the potential of mass spectrometry for assisting in the discovery of new stilbenes of biomedical importance, elucidating their mechanisms of action, and quantifying minute quantities in complex matrices is far from being exhausted.

  11. Mass spectrometry-based biochemical assays for enzymeinhibitor screening

    NARCIS (Netherlands)

    de Boer, A.R.; Lingeman, H.; Niessen, W.M.A.; Irth, H.

    2007-01-01

    Screening for inhibitors of pharmacologically-relevant enzymes is in many cases an important starting point in drug discovery. While fluorescence-based detection techniques play an important role in high-throughput screening, mass spectrometry (MS)-based assays have gained in importance in recent

  12. Mass Spectrometry Method for Quantification of Telmisartan in Hum

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple, rapid, sensitive and specific ultraperformance liquid chromatography mass spectrometry method for the quantification of the angiotensin II receptor antagonist, telmisartan (TEL), in human plasma. Methods: After simple protein precipitation using acetonitrile and methanol, TEL and ...

  13. Mass Spectrometry Imaging for the Classification of Tumor Tissue

    NARCIS (Netherlands)

    Mascini, N.E.

    2016-01-01

    Mass spectrometry imaging (MSI) can detect and identify many different molecules without the need for labeling. In addition, it can provide their spatial distributions as ‘molecular maps’. These features make MSI well suited for studying the molecular makeup of tumor tissue. Currently, there is an

  14. Gas chromatography mass spectrometry : key technology in metabolomics

    NARCIS (Netherlands)

    Koek, Maud Marijtje

    2009-01-01

    Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with

  15. Mass spectrometry: Raw protein from the top down

    Science.gov (United States)

    Breuker, Kathrin

    2018-02-01

    Mass spectrometry is a powerful technique for analysing proteins, yet linking higher-order protein structure to amino acid sequence and post-translational modifications is far from simple. Now, a native top-down method has been developed that can provide information on higher-order protein structure and different proteoforms at the same time.

  16. Decoding signalling networks by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Choudhary, Chuna Ram; Mann, Matthias

    2010-01-01

    Signalling networks regulate essentially all of the biology of cells and organisms in normal and disease states. Signalling is often studied using antibody-based techniques such as western blots. Large-scale 'precision proteomics' based on mass spectrometry now enables the system...

  17. Traveling-wave ion mobility mass spectrometry of protein complexes

    DEFF Research Database (Denmark)

    Salbo, Rune; Bush, Matthew F; Naver, Helle

    2012-01-01

    The collision cross-section (Ω) of a protein or protein complex ion can be measured using traveling-wave (T-wave) ion mobility (IM) mass spectrometry (MS) via calibration with compounds of known Ω. The T-wave Ω-values depend strongly on instrument parameters and calibrant selection. Optimization...

  18. Data analysis for mass spectrometry imaging : methods and applications

    NARCIS (Netherlands)

    Abdelmoula, Walid Mohamed

    2017-01-01

    In this dissertation we developed a number of automatic methods for multi-modal data registration, mainly between mass spectrometry imaging, imaging microscopy, and the Allen Brain Atlas. We have shown the importance of these methods for performing large scale preclinical biomarker discovery

  19. Capillary electrophoresis-mass spectrometry for the analysis of biopharmaceuticals

    NARCIS (Netherlands)

    Haselberg, Rob; De Jong, Gerhardus J.; Somsen, Govert W.

    2012-01-01

    Developments in the fields of protein chemistry and pharmaceutical biotechnology have increased the demand for suitable analytical techniques for the characterization of intact proteins. Capillary electrophoresis (CE) coupled to mass spectrometry (MS) has proven to be a powerful tool for this

  20. Capillary electrophoresis-mass spectrometry for the analysis of Biopharmaceuticals

    NARCIS (Netherlands)

    Haselberg, Rob; de Jong, Gerhardus J.; Somsen, Govert W.

    2012-01-01

    Developments in the fields of protein chemistry and pharmaceutical biotechnology have increased the demand for suitable analytical techniques for the characterization of intact proteins. Capillary electrophoresis (CE) coupled to mass spectrometry (MS) has proven to be a powerful tool for this

  1. Kinetic Studies of Reactions in Solution Using Fast Mass Spectrometry

    Science.gov (United States)

    2013-08-13

    fuel source. Many hypergols are toxic, corrosive , and/or volatile such that they are difficult to handle and harmful to the environment. Dicyanamide... electrochemistry and the mass spectrometry analysis of the solutions in which an electrocatalyst is present. NN NN ee meetthyll vviioolloogeenn (93

  2. Online eluent-switching technique coupled anion-exchange liquid chromatography–ion trap tandem mass spectrometry for analysis of non-steroidal anti-inflammatory drugs in pig serum.

    Science.gov (United States)

    Chang, Kai Chun; Lin, Jyh Shiun; Cheng, Cheanyeh

    2015-11-27

    A novel method for online extraction, pH-gradient separation, and analysis of nine non-steroidal anti-inflammatory drugs (NSAIDs) was developed by coupling online eluent-switching technique to single anion-exchange chromatographic column/ion trap mass spectrometer (MS) and used for monitoring NSAIDs residues in pig serum. A neutral eluent and a pH-gradient eluent were used for extraction and separation of NSAIDs, respectively. Each of nine NSAIDs has an MS precursor ion of either [M−H]− or [M−Na]−. The extracted ion chromatogram for a specific product ion of each NSAID was used for its quantitative analysis. The dynamic linear ranges of calibration curves were all 0–200 ng mL−1 (R2 > 0.9950). The analysis accuracies estimated by spiking standard concentrations at 20, 100, and 200 ng mL−1 were 80.5–99.9%. The corresponding intra-day and inter-day precisions (RSD%) were 2.5–14.5% and 2.9–15.2%, respectively. The limit of detection/limit of quantitation of NSAIDs were 1.3/4.3, 0.5/1.6, 0.2/0.5, 2.5/8.2, 1.5/4.9, 0.6/2.1, 0.6/2.0, 0.5/1.7, and 0.6/2.1 ng mL−1 for carprofen, diclofenac, flunixin, ibuprofen, ketoprofen, meclofenamic acid sodium, mefenamic acid, niflumic acid, and tolfenamic acid, respectively. After 1 h injection of a dose containing 2 mg kg−1 weight pig of flunixin and tolfenamic acid to the pigs, a residue amount of 3480 ± 36 ng mL−1 and 431 ± 13 ng mL−1, respectively, was reached for the incurred pig serum specimens and both residues were reduced to about 20 ng mL−1 at the time of 24 h.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Capillary electrophoresis-mass spectrometry of carbohydrates

    Science.gov (United States)

    Zaia, Joseph

    2014-01-01

    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This review summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications. PMID:23386333

  5. Application of Laser Mass Spectrometry to Art and Archaeology

    Science.gov (United States)

    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.

  6. Frontal affinity chromatography-mass spectrometry.

    Science.gov (United States)

    Ng, Ella S M; Chan, Nora W C; Lewis, Darren F; Hindsgaul, Ole; Schriemer, David C

    2007-01-01

    Frontal affinity chromatography (FAC) is a biophysical method for the discovery and characterization of molecular interactions in a flow-based system. Several different modes of analysis are possible by interfacing to the mass spectrometer, including robust single-compound characterizations as well as high-throughput screening of over 1,000 compounds per run. The method supports thermodynamic and kinetic characterization of interactions for a wide range of molecular species and possesses similarities to flow-based biosensors such as surface plasmon resonance. It offers sensitive detection of ligands present well below their respective dissociation constants, and can be assembled from readily available laboratory components. Direct coupling of the FAC cartridge to the mass spectrometer is useful for the interrogation of single compounds or mixtures of limited complexity. An offline fractionation schema is more appropriate for discovery-mode applications. A high-performance FAC system enabling both modes can be assembled in 2-3 h. Measurements of dissociation constants can be made with such a system in 0.5-3 h, and the system supports higher-throughput screening modes at a rate of 10,000 compounds d(-1).

  7. Liquid chromatography-mass spectrometry in forensic toxicology.

    Science.gov (United States)

    Van Bocxlaer, J F; Clauwaert, K M; Lambert, W E; Deforce, D L; Van den Eeckhout, E G; De Leenheer, A P

    2000-01-01

    Liquid chromatography-mass spectrometry has evolved from a topic of mainly research interest into a routinely usable tool in various application fields. With the advent of new ionization approaches, especially atmospheric pressure, the technique has established itself firmly in many areas of research. Although many applications prove that LC-MS is a valuable complementary analytical tool to GC-MS and has the potential to largely extend the application field of mass spectrometry to hitherto "MS-phobic" molecules, we must recognize that the use of LC-MS in forensic toxicology remains relatively rare. This rarity is all the more surprising because forensic toxicologists find themselves often confronted with the daunting task of actually searching for evidence materials on a scientific basis without any indication of the direction in which to search. Through the years, mass spectrometry, mainly in the GC-MS form, has gained a leading role in the way such quandaries are tackled. The advent of robust, bioanalytically compatible combinations of liquid chromatographic separation with mass spectrometric detection really opens new perspectives in terms of mass spectrometric identification of difficult molecules (e.g., polar metabolites) or biopolymers with toxicological relevance, high throughput, and versatility. Of course, analytical toxicologists are generally mass spectrometry users rather than mass spectrometrists, and this difference certainly explains the slow start of LC-MS in this field. Nevertheless, some valuable applications have been published, and it seems that the introduction of the more universal atmospheric pressure ionization interfaces really has boosted interests. This review presents an overview of what has been realized in forensic toxicological LC-MS. After a short introduction into LC-MS interfacing operational characteristics (or limitations), it covers applications that range from illicit drugs to often abused prescription medicines and some

  8. CYLINDER OF THE DISPOSABLE MASS EXCHANGE DEVICE FOR HEMOSORPTION

    Directory of Open Access Journals (Sweden)

    F. I. Kazakov

    2015-01-01

    Full Text Available BACKGROUND. Hemocarboperfusion, previously widely used in our country, can universally pass out of use due to the lack of industrial production of disposable mass exchange devices.MATERIAl AND METHODS. Physicochemical properties of materials and design features of the body samples elements of various sizes have been studied.RESULTS. The elements and materials properties of the hemosorption mass exchanger cylinder have been studied. Hydrodynamic parameters of manipulation using the developed cylinders at different perfusion rates have been studied in bench experiments.CONCLUSION. The original cylinder of the disposable mass exchange device for hemosorption, which meets the current clinical needs, has been developed. 

  9. Multiresidue pesticide analysis by capillary gas chromatography-mass spectrometry.

    Science.gov (United States)

    Wong, Jon W; Zhang, Kai; Hayward, Douglas G; Kai-Meng, Chin

    2011-01-01

    A multiresidue pesticide method using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure and capillary gas chromatography-mass spectrometry (GC-MS) is described for the determination of 166 organochlorine, organophosphorus, and pyrethroid pesticides, metabolites, and isomers in spinach. The pesticides from spinach were extracted using acetonitrile saturated with magnesium sulfate and sodium chloride, followed by solid-phase dispersive cleanup using primary-secondary amine and graphitized carbon black sorbents and toluene. Analysis is performed using different GC-MS techniques emphasizing the benefits of non-targeted acquisition and targeted screening procedures. Non-targeted data acquisition of pesticides in the spinach was demonstrated using GC coupled to a single quadrupole mass spectrometery (GC-MS) in full scan mode or multidimensional GC-time-of-flight mass spectrometery (GC  ×  GC-TOF/MS), along with deconvolution software and libraries. Targeted screening was achieved using GC-single quadrupole mass spectrometry in selective ion monitoring (GC-MS/SIM) mode or -tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring mode. The development of these techniques demonstrates the powerful use of GC-MS for the screening, identification, and quantitation of pesticide residues in foods.

  10. Estimating the Efficiency of Phosphopeptide Identification by Tandem Mass Spectrometry

    Science.gov (United States)

    Hsu, Chuan-Chih; Xue, Liang; Arrington, Justine V.; Wang, Pengcheng; Paez Paez, Juan Sebastian; Zhou, Yuan; Zhu, Jian-Kang; Tao, W. Andy

    2017-06-01

    Mass spectrometry has played a significant role in the identification of unknown phosphoproteins and sites of phosphorylation in biological samples. Analyses of protein phosphorylation, particularly large scale phosphoproteomic experiments, have recently been enhanced by efficient enrichment, fast and accurate instrumentation, and better software, but challenges remain because of the low stoichiometry of phosphorylation and poor phosphopeptide ionization efficiency and fragmentation due to neutral loss. Phosphoproteomics has become an important dimension in systems biology studies, and it is essential to have efficient analytical tools to cover a broad range of signaling events. To evaluate current mass spectrometric performance, we present here a novel method to estimate the efficiency of phosphopeptide identification by tandem mass spectrometry. Phosphopeptides were directly isolated from whole plant cell extracts, dephosphorylated, and then incubated with one of three purified kinases—casein kinase II, mitogen-activated protein kinase 6, and SNF-related protein kinase 2.6—along with 16O4- and 18O4-ATP separately for in vitro kinase reactions. Phosphopeptides were enriched and analyzed by LC-MS. The phosphopeptide identification rate was estimated by comparing phosphopeptides identified by tandem mass spectrometry with phosphopeptide pairs generated by stable isotope labeled kinase reactions. Overall, we found that current high speed and high accuracy mass spectrometers can only identify 20%-40% of total phosphopeptides primarily due to relatively poor fragmentation, additional modifications, and low abundance, highlighting the urgent need for continuous efforts to improve phosphopeptide identification efficiency. [Figure not available: see fulltext.

  11. Imaging mass spectrometry with nuclear microprobes for biological applications

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Y. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)], E-mail: yukai@nucleng.kyoto-u.ac.jp; Yamada, H.; Honda, Y. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Ninomiya, S. [Quantum Science and Engineering Center, Kyoto University, Uji, Kyoto 611-0011 (Japan); Seki, T. [Department of Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan); Aoki, T. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan); Matsuo, J. [Quantum Science and Engineering Center, Kyoto University, Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency, Chiyoda, Tokyo 102-0075 (Japan)

    2009-06-15

    A mass spectrometric technique using nuclear microprobes is presented in this paper for biological applications. In recent years, imaging mass spectrometry has become an increasingly important technique for visualizing the spatial distribution of molecular species in biological tissues and cells. However, due to low yields of large molecular ions, the conventional secondary ion mass spectrometry (SIMS), that uses keV primary ion beams, is typically applied for imaging of either elements or low mass compounds. In this study, we performed imaging mass spectrometry using MeV ion beams collimated to about 10 {mu}m, and successfully obtained molecular ion images from plant and animal cell sections. The molecular ion imaging of the pollen section showed high intensities of PO{sub 3}{sup -} ions in the pollen cytoplasm, compared to the pollen wall, and indicated the heterogeneous distribution in the cytoplasm. The 3T3-L1 cell image revealed the high intensity of PO{sub 3}{sup -} ions, in particular from the cell nucleus. The result showed that not only the individual cell, but also the cell nucleus could be identified with the present imaging technique.

  12. Matrix-assisted laser desorption/ionization imaging mass spectrometry.

    Science.gov (United States)

    Zaima, Nobuhiro; Hayasaka, Takahiro; Goto-Inoue, Naoko; Setou, Mitsutoshi

    2010-01-01

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful tool that enables the simultaneous detection and identification of biomolecules in analytes. MALDI-imaging mass spectrometry (MALDI-IMS) is a two-dimensional MALDI-mass spectrometric technique used to visualize the spatial distribution of biomolecules without extraction, purification, separation, or labeling of biological samples. MALDI-IMS has revealed the characteristic distribution of several biomolecules, including proteins, peptides, amino acids, lipids, carbohydrates, and nucleotides, in various tissues. The versatility of MALDI-IMS has opened a new frontier in several fields such as medicine, agriculture, biology, pharmacology, and pathology. MALDI-IMS has a great potential for discovery of unknown biomarkers. In this review, we describe the methodology and applications of MALDI-IMS for biological samples.

  13. T cells recognizing a peptide contaminant undetectable by mass spectrometry

    DEFF Research Database (Denmark)

    Brezar, Vedran; Culina, Slobodan; Østerbye, Thomas

    2011-01-01

    Synthetic peptides are widely used in immunological research as epitopes to stimulate their cognate T cells. These preparations are never completely pure, but trace contaminants are commonly revealed by mass spectrometry quality controls. In an effort to characterize novel major histocompatibility...... complex (MHC) Class I-restricted ß-cell epitopes in non-obese diabetic (NOD) mice, we identified islet-infiltrating CD8+ T cells recognizing a contaminating peptide. The amount of this contaminant was so small to be undetectable by direct mass spectrometry. Only after concentration by liquid...... chromatography, we observed a mass peak corresponding to an immunodominant islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)(206-214) epitope described in the literature. Generation of CD8+ T-cell clones recognizing IGRP(206-214) using a novel method confirmed the identity...

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Velocity map imaging in time of flight mass spectrometry.

    Science.gov (United States)

    Brouard, M; Campbell, E K; Johnsen, A J; Vallance, C; Yuen, W H; Nomerotski, A

    2008-12-01

    A new variation on time of flight mass spectrometry is presented, which uses a fast framing charge coupled device camera to velocity map image multiple product masses in a single acquisition. The technique is demonstrated on two photofragmentation processes, those of CS(2) and CH(3)S(2)CH(3) (dimethyldisulfide) at a photolysis wavelength of 193 nm. In both cases, several mass fragments are imaged simultaneously, and speed distributions and anisotropy parameters are extracted that are comparable to those obtained by imaging each fragment separately in conventional velocity map imaging studies.

  16. Use of mass spectrometry for imaging metabolites in plants.

    Science.gov (United States)

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

    2012-04-01

    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. Published 2012. This article is a US Government work and is in the public domain in the USA.

  17. Identification of carbohydrate anomers using ion mobility-mass spectrometry

    Science.gov (United States)

    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.

  18. New Types of Ionization Sources for Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    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.

  19. Preliminary mass spectrometry characterization studies of galectin-3 samples, prior to carbohydrate-binding studies using Affinity mass spectrometry.

    Science.gov (United States)

    Jovanović, Marko; Peter-Katalinić, Jasna

    2017-01-15

    Investigation of non-covalent complexes of proteins using Affinity Mass Spectrometry (AMS) represents a major challenge in modern biomedical research. However, many experimental obstacles can make AMS data analysis complex. Additionally, sample purity and size of the protein may still pose significant challenges. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) was used for initial mapping of protein samples. nanoESI (electrospray ionization) quadrupole-time-of-flight (QTOF) MS was used for mapping of protein samples under native conditions and subsequent AMS studies. The human galectin-3 protein sample was expressed in E. coli. Full length galectin-3 was difficult to work with, due to several truncated forms observed after the purification procedures. On the other hand, galectin-3C produced excellent quality nanoESI-MS spectra. A covalent adduct of lactose was found to be located on residue Lys 176. Functional AMS control studies indicated that galectin-3 interactions with oligosaccharides may be dependent on its charge. Mass spectrometry represents a valuable tool that can be efficiently used for structural characterization of protein samples prior to functional analyses. By means of accurate mass measurements, many protein truncations can be identified based on mass alone. Analysis of covalent adducts is more challenging. Finally, for AMS studies, careful use of controls may reveal charge-dependence of protein-oligosaccharide interactions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Metabolism of halogenated compounds in the white rot fungus Bjerkandera adusta studied by membrane inlet mass spectrometry and tandem mass spectrometry

    DEFF Research Database (Denmark)

    Beck, Hans Christian; Lauritsen, F.R.; Patrick, J.S.

    1996-01-01

    Membrane inlet mass spectrometry has been used for the characterization of halogenated organic compounds produced by the fungus Bjerkandera adusta. Using this technique, electron impact-, chemical ionization-, electron capture negative chemical ionization-mass spectra and tandem mass spectra were...

  1. Characterisation of covalent copper and manganese organometallic complexes with Schiff bases by ionspray mass spectrometry

    NARCIS (Netherlands)

    Raffaelli, A.; Minutolo, F.; Feringa, B.L.; Salvadori, P.

    1998-01-01

    Copper and manganese complexes containing Schiff bases as ligands, having potential interest in homogeneous catalysis, have been characterised by mass spectrometry using ionspray ionisation. Single stage mass spectrometry allowed us to confirm the molecular weight of complexes in all cases,

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. Mass spectrometry imaging of biological tissue: an approach for multicenter studies.

    Science.gov (United States)

    Römpp, Andreas; Both, Jean-Pierre; Brunelle, Alain; Heeren, Ron M A; Laprévote, 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, MALDI-Fourier 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

  4. Gelatin quantification by oxygen-18 labeling and liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    Sha, Xiao-Mei; Tu, Zong-Cai; Wang, Hui; Huang, Tao; Duan, Deng-Le; He, Na; Li, De-Jun; Xiao, Hui

    2014-12-10

    Combined with high-performance liquid chromatography (HPLC) and linear-ion trap/Orbitrap high-resolution mass spectrometry, trypsin-catalyzed (16)O-to-(18)O exchange was used to establish an accurate quantitative method for bovine or porcine gelatin. The sophisticated modifications for these two mammalian gelatins were unambiguously identified by accurate mass and tandem mass spectrometry. Eighteen marker peptides were successfully identified for the bovine and porcine gelatin, respectively. The gelatins were subjected to (18)O or (16)O labeling in the presence of trypsin and mixed together in various ratios for quantification. All of the (18)O-labeled peptides were also confirmed by accurate mass and tandem mass spectrometry. The 10 marker peptides with the strongest signals were chosen to calculate the average ratios of (18)O-labeled and (16)O-labeled gelatin. The measured ratios of (18)O-labeled and (16)O-labeled peptides were very close to the mixing ratios of 20:1, 5:1, 1:1, and 1:5 with low standard deviation values. The samples with a mixing ratio of 1:1 (18)O-labeled and (16)O-labeled peptides were determined to 1.00 and 0.99 with standard deviations of 0.02 and 0.04 for bovine and porcine gelatins, respectively, indicating the high accuracy of this method. Trypsin-catalyzed (18)O labeling was proved to be an excellent internal calibrant for gelatins. When combined with HPLC and high-resolution mass spectrometry, it is an accurate and sensitive quantitative method for gelatin in the food industry.

  5. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    Science.gov (United States)

    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

  6. Establishing Drug Resistance in Microorganisms by Mass Spectrometry

    Science.gov (United States)

    Demirev, Plamen A.; Hagan, Nathan S.; Antoine, Miquel D.; Lin, Jeffrey S.; Feldman, Andrew B.

    2013-08-01

    A rapid method to determine drug resistance in bacteria based on mass spectrometry is presented. In it, a mass spectrum of an intact microorganism grown in drug-containing stable isotope-labeled media is compared with a mass spectrum of the intact microorganism grown in non-labeled media without the drug present. Drug resistance is determined by predicting characteristic mass shifts of one or more microorganism biomarkers using bioinformatics algorithms. Observing such characteristic mass shifts indicates that the microorganism is viable even in the presence of the drug, thus incorporating the isotopic label into characteristic biomarker molecules. The performance of the method is illustrated on the example of intact E. coli, grown in control (unlabeled) and 13C-labeled media, and analyzed by MALDI TOF MS. Algorithms for data analysis are presented as well.

  7. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    Directory of Open Access Journals (Sweden)

    Lucy Lim

    2016-01-01

    Full Text Available 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.

  8. Recent directions of electrospray mass spectrometry for elemental speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schaumloeffel, Dirk [Universite de Pau et des Pays de l' Adour/CNRS UMR 5254, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement/IPREM, Pau (France); Tholey, Andreas [Christian-Albrechts-Universitaet, Institute for Experimental Medicine - Div. Systematic Proteome Research, Kiel (Germany)

    2011-06-15

    A brief survey is given of the last 2 years' literature on electrospray mass spectrometry (ESI-MS) for speciation analysis. As observed for many years, the main recent applications in this field concern arsenic and selenium species, especially in studies encompassing combined use of molecular and element mass spectrometry. A further application field is the stoichiometric characterization of metal complexes by ESI-MS, which in some studies was assisted by nuclear magnetic resonance spectroscopy. A few examples are presented to illustrate arsenic species involved in metabolic pathways, sulfur species in oils and bitumen, and aluminum complexes. On the basis of this review, we also give an outlook of expected future developments and trends in this research field. (orig.)

  9. Development of Accelerator Mass Spectrometry at the Lund Pelletron

    Science.gov (United States)

    Hellborg, R.; Curtis, L. J.; Erlandsson, B.; Faarinen, M.; Kiisk, M.; Magnusson, C.-E.; Persson, P.; Skog, G.; Stenström, K.

    Accelerator mass spectrometry (AMS) is a highly sensitive method for counting atoms. It is used for detecting very low concentrations of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg size) and shorter measuring times (less than one hour). In AMS, rare isotopes from a sample material placed in the ion source of an electrostatic tandem accelerator are measured by counting individual atoms with nuclear detection techniques after acceleration to energies in the MeV range. A dramatic improvement in background rejection for AMS systems has, in the best cases, led to a 108 increase in sensitivity for isotope ratio measurements compared to the older technique of mass spectrometry. In this report some current applications of the AMS technique at the Lund Pelletron accelerator, as well as the recent improvements of the Lund system, are presented.

  10. Discovery based and targeted Mass Spectrometry in farm animal proteomics

    DEFF Research Database (Denmark)

    Bendixen, Emøke

    2013-01-01

    Technological advances in mass spectrometry have greatly improved accuracy and speed of analyses of proteins and biochemical pathways. These proteome technologies have transformed research and diagnostic methods in the biomedical fields, and in food and farm animal sciences proteomics can be used...... to investigate and monitor specific marker proteins and peptides within complex food matrices, as for example, for guaranteeing safety and quality of processed and stored foods like cheese and cured meat. Likewise, specific diagnostic markers associated with compromised welfare, or with early infections can...... for investigating farm animal biology. SRM is particularly important for validation biomarker candidates This talk will introduce the use of different mass spectrometry approaches through examples related to food quality and animal welfare, including studies of gut health in pigs, host pathogen interactions...

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

    Science.gov (United States)

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

    2008-04-01

    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 because of 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 that this behavior is highly complex and needs to be further explored. John Wiley & Sons, Ltd

  12. Statistical methods for quantitative mass spectrometry proteomic experiments with labeling

    Directory of Open Access Journals (Sweden)

    Oberg Ann L

    2012-11-01

    Full Text Available Abstract Mass Spectrometry utilizing labeling allows multiple specimens to be subjected to mass spectrometry simultaneously. As a result, between-experiment variability is reduced. Here we describe use of fundamental concepts of statistical experimental design in the labeling framework in order to minimize variability and avoid biases. We demonstrate how to export data in the format that is most efficient for statistical analysis. We demonstrate how to assess the need for normalization, perform normalization, and check whether it worked. We describe how to build a model explaining the observed values and test for differential protein abundance along with descriptive statistics and measures of reliability of the findings. Concepts are illustrated through the use of three case studies utilizing the iTRAQ 4-plex labeling protocol.

  13. Native Mass Spectrometry in Fragment-Based Drug Discovery

    Directory of Open Access Journals (Sweden)

    Liliana Pedro

    2016-07-01

    Full Text Available 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.

  14. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery

    Science.gov (United States)

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

    2007-01-01

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

  15. Challenges ahead for mass spectrometry and proteomics applications in epigenetics.

    Science.gov (United States)

    Kessler, Benedikt M

    2010-02-01

    Inheritance of biological information to future generations depends on the replication of DNA and the Mendelian principle of distribution of genes. In addition, external and environmental factors can influence traits that can be propagated to offspring, but the molecular details of this are only beginning to be understood. The discoveries of DNA methylation and post-translational modifications on chromatin and histones provided entry points for regulating gene expression, an area now defined as epigenetics and epigenomics. Mass spectrometry turned out to be instrumental in uncovering molecular details involved in these processes. The central role of histone post-translational modifications in epigenetics related biological processes has revitalized mass spectrometry based investigations. In this special report, current approaches and future challenges that lay ahead due to the enormous complexity are discussed.

  16. Sharing and community curation of mass spectrometry data with GNPS

    Science.gov (United States)

    Nguyen, Don Duy; Watrous, Jeramie; Kapono, Clifford A; Luzzatto-Knaan, Tal; Porto, Carla; Bouslimani, Amina; Melnik, Alexey V; Meehan, Michael J; Liu, Wei-Ting; Crüsemann, Max; Boudreau, Paul D; Esquenazi, Eduardo; Sandoval-Calderón, Mario; Kersten, Roland D; Pace, Laura A; Quinn, Robert A; Duncan, Katherine R; Hsu, Cheng-Chih; Floros, Dimitrios J; Gavilan, Ronnie G; Kleigrewe, Karin; Northen, Trent; Dutton, Rachel J; Parrot, Delphine; Carlson, Erin E; Aigle, Bertrand; Michelsen, Charlotte F; Jelsbak, Lars; Sohlenkamp, Christian; Pevzner, Pavel; Edlund, Anna; McLean, Jeffrey; Piel, Jörn; Murphy, Brian T; Gerwick, Lena; Liaw, Chih-Chuang; Yang, Yu-Liang; Humpf, Hans-Ulrich; Maansson, Maria; Keyzers, Robert A; Sims, Amy C; Johnson, Andrew R.; Sidebottom, Ashley M; Sedio, Brian E; Klitgaard, Andreas; Larson, Charles B; P., Cristopher A Boya; Torres-Mendoza, Daniel; Gonzalez, David J; Silva, Denise B; Marques, Lucas M; Demarque, Daniel P; Pociute, Egle; O'Neill, Ellis C; Briand, Enora; Helfrich, Eric J. N.; Granatosky, Eve A; Glukhov, Evgenia; Ryffel, Florian; Houson, Hailey; Mohimani, Hosein; Kharbush, Jenan J; Zeng, Yi; Vorholt, Julia A; Kurita, Kenji L; Charusanti, Pep; McPhail, Kerry L; Nielsen, Kristian Fog; Vuong, Lisa; Elfeki, Maryam; Traxler, Matthew F; Engene, Niclas; Koyama, Nobuhiro; Vining, Oliver B; Baric, Ralph; Silva, Ricardo R; Mascuch, Samantha J; Tomasi, Sophie; Jenkins, Stefan; Macherla, Venkat; Hoffman, Thomas; Agarwal, Vinayak; Williams, Philip G; Dai, Jingqui; Neupane, Ram; Gurr, Joshua; Rodríguez, Andrés M. C.; Lamsa, Anne; Zhang, Chen; Dorrestein, Kathleen; Duggan, Brendan M; Almaliti, Jehad; Allard, Pierre-Marie; Phapale, Prasad; Nothias, Louis-Felix; Alexandrov, Theodore; Litaudon, Marc; Wolfender, Jean-Luc; Kyle, Jennifer E; Metz, Thomas O; Peryea, Tyler; Nguyen, Dac-Trung; VanLeer, Danielle; Shinn, Paul; Jadhav, Ajit; Müller, Rolf; Waters, Katrina M; Shi, Wenyuan; Liu, Xueting; Zhang, Lixin; Knight, Rob; Jensen, Paul R; Palsson, Bernhard O; Pogliano, Kit; Linington, Roger G; Gutiérrez, Marcelino; Lopes, Norberto P; Gerwick, William H; Moore, Bradley S; Dorrestein, Pieter C; Bandeira, Nuno

    2017-01-01

    The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS, http://gnps.ucsd.edu), an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data. PMID:27504778

  17. Proposal on dynamic correction method for resonance ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Noto, Takuma, E-mail: noto.takuma@d.mbox.nagoya-u.ac.jp; Tomita, Hideki [Nagoya University, Department of Quantum Engineering (Japan); Richter, Sven; Schneider, Fabian; Wendt, Klaus [Johannes Gutenberg University Mainz, Institute of Physics (Germany); Iguchi, Tetsuo; Kawarabayashi, Jun [Nagoya University, Department of Quantum Engineering (Japan)

    2013-04-15

    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.

  18. Advances in characterizing ubiquitylation sites by mass spectrometry

    DEFF Research Database (Denmark)

    Sylvestersen, K.B.; Young, C.; Nielsen, M.L.

    2013-01-01

    The attachment of one or more ubiquitin moieties to proteins plays a central regulatory mechanism in eukaryotic cells. Protein ubiquitylation regulates numerous cellular processes, including protein degradation, signal transduction, DNA repair and cell division. The characterization...... of ubiquitylation is a two-fold challenge that involves the mapping of ubiquitylation sites and the determination of ubiquitin chain topology. This review focuses on the technical advances in the mass spectrometry-based characterization of ubiquitylation sites, which have recently involved the large...

  19. Accelerator mass spectrometry for quantitative in vivo tracing

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Stable Isotope Dilution Mass Spectrometry for Membrane Transporter Quantitation

    OpenAIRE

    Farrokhi, Vahid; McShane, Adam J.; Nemati, Reza; Yao, Xudong

    2013-01-01

    This review provides an introduction to stable isotope dilution mass spectrometry (MS) and its emerging applications in the analysis of membrane transporter proteins. Various approaches and application examples, for the generation and use of quantitation reference standards—either stable isotope-labeled peptides or proteins—are discussed as they apply to the MS quantitation of membrane proteins. Technological considerations for the sample preparation of membrane transporter proteins are also ...

  1. Time of flight mass spectrometry of pharmaceutical systems

    OpenAIRE

    Armitage Nolan, Jennifer Claire

    2013-01-01

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a widely used surface chemical analysis technique that is traditionally employed to characterise the first few molecular layers of a material interface. The ability of this technique to accurately reflect the surface chemistry of polymers, biomaterials and many other solid materials is well documented. However, the majority of research that utilises this technique is based upon a qualitative rather than quantitative assessment of th...

  2. Significant advancement of mass spectrometry imaging for food chemistry.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Computational quality control tools for mass spectrometry proteomics.

    Science.gov (United States)

    Bittremieux, Wout; Valkenborg, Dirk; Martens, Lennart; Laukens, Kris

    2017-02-01

    As mass-spectrometry-based proteomics has matured during the past decade, a growing emphasis has been placed on quality control. For this purpose, multiple computational quality control tools have been introduced. These tools generate a set of metrics that can be used to assess the quality of a mass spectrometry experiment. Here we review which types of quality control metrics can be generated, and how they can be used to monitor both intra- and inter-experiment performances. We discuss the principal computational tools for quality control and list their main characteristics and applicability. As most of these tools have specific use cases, it is not straightforward to compare their performances. For this survey, we used different sets of quality control metrics derived from information at various stages in a mass spectrometry process and evaluated their effectiveness at capturing qualitative information about an experiment using a supervised learning approach. Furthermore, we discuss currently available algorithmic solutions that enable the usage of these quality control metrics for decision-making. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Biomarker Motif Discovery by Integrating Mass Spectrometry and PPI Network

    Science.gov (United States)

    Zhou, Xiaobo; Wang, Yuan; Wang, Honghui; Pham, Tuan D.; Li, King

    2011-06-01

    Traditional mass spectrometry biomarker discovery studies which focus on single biomarkers or a panel of biomarkers have shown their limitations with low reproducibility. In this paper, we propose a novel biomarker motif discovery approach by integrating both mass spectrometry data and protein interaction network information together to identify biomarkers. A novel Bayesian score method is developed to score the protein subnetwork both from the expression of protein and from the protein interaction network structure. Compared with the previous biomarker discovery method, our biomarker motif identification method not only models the expression of each protein, but also the relationship of proteins affected by the protein-protein interaction network. The experiment results show that our proposed biomarker discovery method has a higher sensitivity and lower false discovery rates than previously used methods. When applying our biomarker motifs discovery approach to the real stroke mass spectrometry data, we can identify several biomarker motifs for ischemic stroke which can achieve a higher classification performance with high biological significance.

  5. Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

    CERN Document Server

    March, Raymond E

    2009-01-01

    Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

  6. Mass spectrometry-based analysis of whole-grain phytochemicals.

    Science.gov (United States)

    Koistinen, Ville Mikael; Hanhineva, Kati

    2017-05-24

    Whole grains are a rich source of several classes of phytochemicals, such as alkylresorcinols, benzoxazinoids, flavonoids, lignans, and phytosterols. A high intake of whole grains has been linked to a reduced risk of some major noncommunicable diseases, and it has been postulated that a complex mixture of phytochemicals works in synergy to generate beneficial health effects. Mass spectrometry, especially when coupled with liquid chromatography, is a widely used method for the analysis of phytochemicals owing to its high sensitivity and dynamic range. In this review, the current knowledge of the mass spectral properties of the most important classes of phytochemicals found in cereals of common wheat, barley, oats, and rye is discussed.

  7. Characterization of individual particles in gaseous media by mass spectrometry

    Science.gov (United States)

    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.

  8. Temperature-programmed desorption for membrane inlet mass spectrometry

    DEFF Research Database (Denmark)

    Ketola, R.A.; Grøn, C.; Lauritsen, F.R.

    1998-01-01

    We present a novel technique for analyzing volatile organic compounds in air samples using a solid adsorbent together with temperature-programmed desorption and subsequent detection by membrane inlet mass spectrometry (TPD-MIMS). The new system has the advantage of a fast separation of compounds...... to diffuse through the membrane into the mass spectrometer in a few seconds. In this fashion we could completely separate many similar volatile compounds, for example toluene from xylene and trichloroethene from tetrachloroethene. Typical detection limits were at low or sub-nanogram levels, the dynamic range...

  9. Structural analyses of sucrose laurate regioisomers by mass spectrometry techniques

    DEFF Research Database (Denmark)

    Lie, Aleksander; Stensballe, Allan; Pedersen, Lars Haastrup

    2015-01-01

    6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore.......8, respectively, and Orbitrap HRMS confirmed the mass of [M+Na]+ (m/z 547.2712). ESI-MS/MS on the precursor ion [M+Na]+ resulted in product ion mass spectra showing two high-intensity signals for each sample. 6-O-Lauroyl sucrose produced signals located at m/z 547.27 and m/z 385.21, corresponding to the 6-O......-lauroyl glucose sodium adduct ions, while the signals for 6′-O-lauroyl sucrose were located at m/z 385.22 and 367.20, respectively corresponding to the sodium adduct ions with 6-O-lauroyl fructose and 6-O-lauroyl fructosyl. The mass spectra of the two regioisomers were clearly different, and the investigation...

  10. Kinetic model of mass exchange with dynamic Arrhenius transition rates

    Science.gov (United States)

    Hristopulos, Dionissios T.; Muradova, Aliki

    2016-02-01

    We study a nonlinear kinetic model of mass exchange between interacting grains. The transition rates follow the Arrhenius equation with an activation energy that depends dynamically on the grain mass. We show that the activation parameter can be absorbed in the initial conditions for the grain masses, and that the total mass is conserved. We obtain numerical solutions of the coupled, nonlinear, ordinary differential equations of mass exchange for the two-grain system, and we compare them with approximate theoretical solutions in specific neighborhoods of the phase space. Using phase plane methods, we determine that the system exhibits regimes of diffusive and growth-decay (reverse diffusion) kinetics. The equilibrium states are determined by the mass equipartition and separation nullcline curves. If the transfer rates are perturbed by white noise, numerical simulations show that the system maintains the diffusive and growth-decay regimes; however, the noise can reverse the sign of equilibrium mass difference. Finally, we present theoretical analysis and numerical simulations of a system with many interacting grains. Diffusive and growth-decay regimes are established as well, but the approach to equilibrium is considerably slower. Potential applications of the mass exchange model involve coarse-graining during sintering and wealth exchange in econophysics.

  11. Membrane device and process for mass exchange, separation, and filtration

    Science.gov (United States)

    Liu, Wei; Canfield, Nathan L.

    2016-11-15

    A membrane device and processes for fabrication and for using are disclosed. The membrane device may include a number of porous metal membranes that provide a high membrane surface area per unit volume. The membrane device provides various operation modes that enhance throughput and selectivity for mass exchange, mass transfer, separation, and/or filtration applications between feed flow streams and permeate flow streams.

  12. Analysis of polar lipids in the serum from rats fed shiitake by liquid chromatography-mass spectrometry/mass spectrometry.

    Science.gov (United States)

    Yu, Shanggong; Peng, Min; Ronis, Martin; Badger, Thomas; Fang, Nianbai

    2010-12-22

    Consumption of a shiitake mushroom diet has been reported to have effects on serum phospholipids. However, much less is known about the effect on serum polar lipids including lysophospholipids and free fatty acids. In the present study, the effects of a shiitake diet were evaluated on the basis of identification and quantification of individual polar lipid components in rat serum using liquid chromatography-mass spectrometry/mass spectrometry. By comparison with standards and published data, 50 lysophospholipids and 32 free fatty acids were identified, and the concentrations of 27 polar lipids in rat serum were determined. Shiitake diets decreased the levels of all individual polar lipid components in the serum of male rat. The total level of serum polar lipids in males fed 4% shiitake diets (1365.71 mol/L) was significantly lower than that of the control (2270.26 mol/L). However, shiitake diets did not significantly affect the levels of serum polar lipids in female rats.

  13. Neuropeptide Signaling in Crustaceans Probed by Mass Spectrometry

    Science.gov (United States)

    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

  14. Ion sampling and transport in Inductively Coupled Plasma Mass Spectrometry

    Science.gov (United States)

    Farnsworth, Paul B.; Spencer, Ross L.

    2017-08-01

    Quantitative accuracy and high sensitivity in inductively coupled plasma mass spectrometry (ICP-MS) depend on consistent and efficient extraction and transport of analyte ions from an inductively coupled plasma to a mass analyzer, where they are sorted and detected. In this review we examine the fundamental physical processes that control ion sampling and transport in ICP-MS and compare the results of theory and computerized models with experimental efforts to characterize the flow of ions through plasma mass spectrometers' vacuum interfaces. We trace the flow of ions from their generation in the plasma, into the sampling cone, through the supersonic expansion in the first vacuum stage, through the skimmer, and into the ion optics that deliver the ions to the mass analyzer. At each stage we consider idealized behavior and departures from ideal behavior that affect the performance of ICP-MS as an analytical tool.

  15. Mass Spectrometry of Aliphatic Macrolides, Important Semiochemicals or Pheromones.

    Science.gov (United States)

    Schulz, Stefan; Peram, Pardha Saradhi; Menke, Markus; Hötling, Susann; Röpke, Rene; Melnik, Kristina; Poth, Dennis; Mann, Florian; Henrichsen, Selma; Dreyer, Katja

    2017-09-22

    Macrolides are a relatively common structural motif prevalent in Nature. However, the structures of these large ring lactones have been relatively difficult to elucidate via NMR spectroscopy due to the minute amounts of compounds that are sometimes obtainable from natural sources. Thus, GC-MS analysis of individual macrolactones has become the method of choice for the structural identification of these compounds. Here we discuss the mass spectrometric behavior of aliphatic macrolides, evaluating spectra from numerous compounds of various ring size, including derivatives containing methyl branches as well as double bonds. The specific fragmentation of these macrolactones under electron impact conditions allows for the development of a general rule set aimed at the identification of similar compounds by mass spectrometry. In addition, the mass spectra of dimethyl disulfide adducts of unsaturated macrolides are discussed. The mass spectra of almost 50 macrolides are presented.

  16. An approach to speed up the isolation of hydrophilic metabolites from natural sources at semipreparative level by using a hydrophilic-lipophilic balance/mixed-mode strong cation exchange-high-performance liquid chromatography/mass spectrometry system.

    Science.gov (United States)

    Espada, Alfonso; Anta, Cristina; Bragado, Aroa; Rodríguez, Jaime; Jiménez, Carlos

    2011-04-01

    An approach to speed up the isolation of hydrophilic metabolites in complex natural matrixes by using a HLB/MCX-HPLC/MS system based on the retention properties of hydrophilic-lipophilic and cation exchange polymeric cartridges was developed. This methodology was successfully applied to the re-isolation of small water soluble compounds with completely different structures from two different natural extracts such as a dipeptide (vanchrobactin) from a bacterium culture broth and a pyrrolidine bearing a carboxylic acid moiety (clionapyrrolidine A) from a sponge. This method improved not only the efficiency of the isolation methodology but also the isolation time in relation to the existing methods. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Electron impact mass spectrometry of alkanes in supersonic molecular beams.

    Science.gov (United States)

    Dagan, S; Amirav, A

    1995-02-01

    The electron impact mass spectrometry of straight chain alkanes C8H18-C40H82, squalane, methylstearate, 1-chlorohexadecane, 1-bromohexadecane, and dioctylphthalate was studied by sampling them with supersonic molecular beams. A fly-through Brink-type electron impact ion source was used, utilizing a vacuum background ion filtration technique based on differences between the kinetic energy of the supersonic beam species and that of thermal molecules. The 70-eV electron impact mass spectra of all the alkanes were characterized by a pronounced or dominant molecular weight peak together with all the fragment ions normally exhibited by the standard thermal 70-eV EI mass spectra. In contrast, the NIST library of most of these molecules did not show any molecular weight peak. By eliminating tile intramolecular thermal vibrational energy we gained control over the degree of molecular ion fragmentation by the electron energy. At an electron energy of 18 eV the molecular ion dissociation was further reduced considerably, with only a small absolute reduction in the peak height by less than a factor of 2. The effect of vibrational cooling increased with the molecular size and number of atoms. Pronounced differences were observed between the mass spectra of the straight chain triacontane and its branched isomer squalane. Similar mass spectra of octacosane (C28H58) achieved with 70-eV EI in a supersonic molecular beam were obtained with a magnetic sector mass spectrometer by using an electron energy of 14 eV and an ion source temperature of 150 °C. However, this ion source temperature precluded the gas chromatography-mass spectrometry (GC-MS) of octacosane. The GC-MS of alkanes was studied with an ion trap gas chromatograph-mass spectrometer at an ion source temperature of 230 °C. Thermal peak tailing was observed for C20H42 and heavier alkanes, whereas for C28H58 and heavier alkanes the severe peak tailing made quantitative GC-MS impractical. In contrast, no peak tailing

  18. Chemical separation and mass spectrometry of Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial materials using thermal ionization mass spectrometry.

    Science.gov (United States)

    Yamakawa, Akane; Yamashita, Katsuyuki; Makishima, Akio; Nakamura, Eizo

    2009-12-01

    A sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks was developed for precise and accurate determination of elemental concentration by the isotope dilution method (ID). The technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The method was tested using a variety of matrixes including bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-1b). Concentrations of each element was determined by thermal ionization mass spectrometry (TIMS) using W filaments and a Si-B-Al type activator for Cr, Fe, Ni, and Zn and a Re filament and silicic acid-H3PO4 activator for Cu. The method can be used to precisely determine the concentrations of these elements in very small silicate samples, including meteorites, geochemical reference samples, and mineral standards for microprobe analysis. Furthermore, the Cr mass spectrometry procedure developed in this study can be extended to determine the isotopic ratios of 53Cr/52Cr and 54Cr/52Cr with precision of approximately 0.05epsilon and approximately 0.10epsilon (1epsilon = 0.01%), respectively, enabling cosmochemical applications such as high precision Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites.

  19. Speciation of arsenic in marine food (Anemonia sulcata) by liquid chromatography coupled to inductively coupled plasma mass spectrometry and organic mass spectrometry.

    Science.gov (United States)

    Contreras-Acuña, M; García-Barrera, T; García-Sevillano, M A; Gómez-Ariza, J L

    2013-03-22

    Arsenic species have been investigated in Anemonia sulcata, which is frequently consumed food staple in Spain battered in wheat flour and fried with olive oil. Speciation in tissue extracts was carried out by anion/cation exchange chromatography with inductively coupled plasma mass spectrometry (HPLC-(AEC/CEC)-ICP-MS). Three methods for the extraction of arsenic species were investigated (ultrasonic bath, ultrasonic probe and focused microwave) and the optimal one was applied. Arsenic speciation was carried out in raw and cooked anemone and the dominant species are dimethylarsinic acid (DMA(V)) followed by arsenobetaine (AB), As(V), monomethylarsonic acid (MA(V)), tetramethylarsonium ion (TETRA) and trimethylarsine oxide (TMAO). In addition, arsenocholine (AsC), glyceryl phosphorylarsenocholine (GPAsC) and dimethylarsinothioic acid (DMAS) were identified by liquid chromatography coupled to triple quadrupole mass spectrometry (HPLC-MS). These results are interesting since GPAsC has been previously reported in marine organisms after experimental exposure to AsC, but not in natural samples. In addition, this paper reports for the first time the identification of DMAS in marine food. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Determination of aminopolycarboxylic acids at ultra-trace levels by means of online coupling ion exchange chromatography and inductively coupled plasma-mass spectrometry with indirect detection via their Pd²⁺-complexes.

    Science.gov (United States)

    Nette, David; Seubert, Andreas

    2015-07-16

    A new indirect IC-ICP-MS method for the determination of aminopolycarboxylic acids in water samples is described. It is based on the addition of an excess of Pd(II) to water samples. The analytes are forced into very strong and negatively charged palladium complexes, separated by ion exchange chromatography and detected by their palladium content, utilizing an on-line coupled ICP-MS. This method is suitable to determine the concentration of 8 aminopolycarboxylic acids (nitrilotriacetic acid (NTA), (2-carboxyethyl) iminodiacetic acid (β-ADA), methylglycinediacetic acid (MGDA), 2-hydroxyethyl) ethylenediamine triacetic acid (HEDTA), diethylene triamine pentaacetic acid (DTPA), ethylendiamine tetraacetic acid (EDTA), 1,3-diaminopropane tetraacetic acid (1,3-PDTA) and 1,2-diaminopropane tetraacetic acid (1,2-PDTA) at the ng kg(-1) level. The method is faster and easier than the established gas chromatography (GC)-method ISO 16588:2002 and up to two orders of magnitude more sensitive than the ion pair chromatography based method of DIN 38413-8. Analytic performance is superior to ISO 16588:2002 and the comparability is good. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Quantitative and confirmative performance of liquid chromatography coupled to high-resolution mass spectrometry compared to tandem mass spectrometry.

    Science.gov (United States)

    Kaufmann, Anton; Butcher, Patrick; Maden, Kathryn; Walker, Stephan; Widmer, Miryam

    2011-04-15

    The quantitative and confirmative performance of two different mass spectrometry (MS) techniques (high-resolution MS and tandem MS) was critically compared. Evaluated was a new extraction and clean-up protocol which was developed to cover more than 100 different veterinary drugs at trace levels in a number of animal tissues and honey matrices. Both detection techniques, high-resolution mass spectrometry (HRMS) (single-stage Orbitrap instrument operated at 50 000 full width at half maximum) and tandem mass spectrometry (MS/MS) (quadrupole technology) were used to validate the method according to the EU Commission Decision 2002/657/EEC. Equal or even a slightly better quantitative performance was observed for the HRMS-based approach. Sensitivity is higher for unit mass resolution MS/MS if only a subset of the 100 compounds has to be monitored. Confirmation of suspected positive findings can be done by evaluating the intensity ratio between different MS/MS transitions, or by accurate mass based product ion traces (no precursor selection applied). MS/MS relies on compound-specific optimized transitions; hence the second, confirmatory transition generally shows relatively high ion abundance (fragmentation efficacy). This is often not the case in single-stage HRMS, since a generic (not compound-optimized) collision energy is applied. Hence, confirmation of analytes present at low levels is superior when performed by MS/MS. Slightly better precision, but poorer accuracy (fortified matrix extracts versus pure standard solution) of ion ratios were observed when comparing data obtained by HRMS versus MS/MS. Copyright © 2011 John Wiley & Sons, Ltd.

  2. On-line coupling of solid-phase extraction with mass spectrometry for the analysis of biological samples I. Determination of clenbuterol in urine

    NARCIS (Netherlands)

    Bruins, C.H P; Jeronimus-Stratingh, C.M; Ensing, K; van Dongen, W.D; de Jong, G.J.

    1999-01-01

    The potential of the direct coupling of solid-phase extraction (SPE) with mass spectrometry (MS) for the analysis of biological samples is demonstrated. For SPE a cartridge exchanger is used and the eluate is directly introduced into the mass spectrometer. This system has been investigated for the

  3. Determination of aminopolycarboxylic acids at ultra-trace levels by means of online coupling ion exchange chromatography and inductively coupled plasma-mass spectrometry with indirect detection via their Pd{sup 2+}-complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nette, David; Seubert, Andreas, E-mail: seubert@staff.uni-marburg.de

    2015-07-16

    Highlights: • 8 important APCA’s analyzed in one run instead of 3 in the previous method. • Pd{sup 2+} extents the methods applicability to 3 and more dentate amino carboxylic acids. • Separation system optimized for the isocratic determination of important APCA’s. • Thermodynamic stability of APCA–Pd{sup 2+} complexes is higher than for Fe{sup 3+} and In{sup 3+}. • Pd{sup 2+} is kinetically much slower than Fe{sup 3+} and In{sup 3+} and makes the method more rugged. - Abstract: A new indirect IC-ICP-MS method for the determination of aminopolycarboxylic acids in water samples is described. It is based on the addition of an excess of Pd(II) to water samples. The analytes are forced into very strong and negatively charged palladium complexes, separated by ion exchange chromatography and detected by their palladium content, utilizing an on-line coupled ICP-MS. This method is suitable to determine the concentration of 8 aminopolycarboxylic acids (nitrilotriacetic acid (NTA), (2-carboxyethyl) iminodiacetic acid (β-ADA), methylglycinediacetic acid (MGDA), 2-hydroxyethyl) ethylenediamine triacetic acid (HEDTA), diethylene triamine pentaacetic acid (DTPA), ethylendiamine tetraacetic acid (EDTA), 1,3-diaminopropane tetraacetic acid (1,3-PDTA) and 1,2-diaminopropane tetraacetic acid (1,2-PDTA) at the ng kg{sup −1} level. The method is faster and easier than the established gas chromatography (GC)-method ISO 16588:2002 [1] and up to two orders of magnitude more sensitive than the ion pair chromatography based method of DIN 38413-8. Analytic performance is superior to ISO 16588:2002 and the comparability is good.

  4. Advances in mass spectrometry-based clinical biomarker discovery.

    Science.gov (United States)

    Crutchfield, Christopher A; Thomas, Stefani N; Sokoll, Lori J; Chan, Daniel W

    2016-01-01

    The greatest unmet needs in biomarker discovery are those discoveries that lead to the development of clinical diagnostic tests. These clinical diagnostic tests can provide early intervention when a patient would present otherwise healthy (e.g., cancer or cardiovascular disease) and aid clinical decision making with improved clinical outcomes. The past two decades have seen significant technological improvements in the analytical capabilities of mass spectrometers. Mass spectrometers are unique in that they can directly analyze any biological molecule susceptible to ionization. The biological studies of human metabolites and proteins using contemporary mass spectrometry technology (metabolomics and proteomics, respectively) has been ongoing for over a decade. Some of these studies have resulted in exciting insights into human biology. However, relatively few biomarkers have been translated into clinical tests. This review will discuss some key technological developments that have occurred over this time with an emphasis on technologies that will create new avenues for biomarker discovery.

  5. Inductively coupled plasma mass spectrometry: recent trends and developments.

    Science.gov (United States)

    Engelhard, Carsten

    2011-01-01

    This year inductively coupled plasma mass spectrometry (ICP-MS) moves into the fourth decade of development. In this article, some recent trends and developments in ICP-MS are reviewed, with special focus on instrumental development and emerging applications. Some key trends include a novel mass spectrometer for elemental and speciation analysis in Mattauch-Herzog geometry with a focal-plane-camera array detector. The reason for this development is the possibility to record the full elemental mass range simultaneously and all the time. Monitoring fast transient signals in chromatography or laser ablation is now possible and will become an important asset in future studies, e.g., for isotope ratio analysis. In addition, there is a lot of new activity and interest in the area of nanosciences and medicine. Here, instrumental developments are reported that allow the direct analysis of microparticles and single cells.

  6. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    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, Steve; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin Shammel

    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.

  7. Uncovering Biologically Significant Lipid Isomers with Liquid Chromatography, Ion Mobility Spectrometry and Mass Spectrometry

    Science.gov (United States)

    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. 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

  8. Mass Spectrometry Based Lipidomics: An Overview of Technological Platforms

    Directory of Open Access Journals (Sweden)

    Harald C. Köfeler

    2012-01-01

    Full Text Available One decade after the genomic and the proteomic life science revolution, new ‘omics’ fields are emerging. The metabolome encompasses the entity of small molecules—Most often end products of a catalytic process regulated by genes and proteins—with the lipidome being its fat soluble subdivision. Within recent years, lipids are more and more regarded not only as energy storage compounds but also as interactive players in various cellular regulation cycles and thus attain rising interest in the bio-medical community. The field of lipidomics is, on one hand, fuelled by analytical technology advances, particularly mass spectrometry and chromatography, but on the other hand new biological questions also drive analytical technology developments. Compared to fairly standardized genomic or proteomic high-throughput protocols, the high degree of molecular heterogeneity adds a special analytical challenge to lipidomic analysis. In this review, we will take a closer look at various mass spectrometric platforms for lipidomic analysis. We will focus on the advantages and limitations of various experimental setups like ‘shotgun lipidomics’, liquid chromatography—Mass spectrometry (LC-MS and matrix assisted laser desorption ionization-time of flight (MALDI-TOF based approaches. We will also examine available software packages for data analysis, which nowadays is in fact the rate limiting step for most ‘omics’ workflows.

  9. Towards airborne nanoparticle mass spectrometry with nanomechanical string resonators

    Science.gov (United States)

    Schmid, Silvan; Kurek, Maksymilian; Boisen, Anja

    2013-06-01

    Airborne nanoparticles can cause severe harm when inhaled. Therefore, small and cheap portable airborne nanoparticle monitors are highly demanded by authorities and the nanoparticle producing industry. We propose to use nanomechanical resonators to build the next generation cheap and portable airborne nanoparticle sensors. Recently, nanomechanical mass spectrometry was established. One of the biggest challenges of nanomechanical sensors is the low efficiency of diffusion-based sampling. We developed an inertial-based sampling method that enables the efficient sampling of airborne nanoparticles on a nanomechanical sensor operating directly in air. We measured a sampling rate of over 1000 particles per second, for 28 nm silica nanoparticles with a concentration of 380000 #/cm3, collected on a 500 nm wide nanomechanical string resonator. We show that it is possible to reach a saturated sampling regime in which 100% of all nanoparticles are captured that are owing in the projection of the nanostring. We further show that it is possible to detect single airborne nanoparticles by detecting 50 nm Au particles with a 250 nm wide string resonator. Our resonators are currently operating in the first bending mode. Mass spectrometry of airborne nanoparticles requires the simultaneous operation in the first and second mode, which can be implemented in the transduction scheme of the resonator. The presented results lay the cornerstone for the realization of a portable airborne nanoparticle mass spectrometer.

  10. Improvements in Mass Spectrometry Assay Library Generation for Targeted Proteomics.

    Science.gov (United States)

    Teleman, Johan; Hauri, Simon; Malmström, Johan

    2017-07-07

    In data-independent acquisition mass spectrometry (DIA-MS), targeted extraction of peptide signals in silico using mass spectrometry assay libraries is a successful method for the identification and quantification of proteins. However, it remains unclear if high quality assay libraries with more accurate peptide ion coordinates can improve peptide target identification rates in DIA analysis. In this study, we systematically improved and evaluated the common algorithmic steps for assay library generation and demonstrate that increased assay quality results in substantially higher identification rates of peptide targets from mouse organ protein lysates measured by DIA-MS. The introduced changes are (1) a new spectrum interpretation algorithm, (2) reapplication of segmented retention time normalization, (3) a ppm fragment mass error matching threshold, (4) usage of internal peptide fragments, and (5) a multilevel false discovery rate calculation. Taken together, these changes yielded 14-36% more identified peptide targets at 1% assay false discovery rate and are implemented in three new open source tools, Fraggle, Tramler, and Franklin, available at https://github.com/fickludd/eviltools . The improved algorithms provide ways to better utilize discovery MS data, translating to substantially increased DIA performance and ultimately better foundations for drawing biological conclusions in DIA-based experiments.

  11. Deep Learning for Tumor Classification in Imaging Mass Spectrometry.

    Science.gov (United States)

    Behrmann, Jens; Etmann, Christian; Boskamp, Tobias; Casadonte, Rita; Kriegsmann, Jörg; Maass, Peter

    2017-11-08

    Tumor classification using Imaging Mass Spectrometry (IMS) data has a high potential for future applications in pathology. Due to the complexity and size of the data, automated feature extraction and classification steps are required to fully process the data. Since mass spectra exhibit certain structural similarities to image data, deep learning may offer a promising strategy for classification of IMS data as it has been successfully applied to image classification. Methodologically, we propose an adapted architecture based on deep convolutional networks to handle the characteristics of mass spectrometry data, as well as a strategy to interpret the learned model in the spectral domain based on a sensitivity analysis. The proposed methods are evaluated on two algorithmically challenging tumor classification tasks and compared to a baseline approach. Competitiveness of the proposed methods are shown on both tasks by studying the performance via cross-validation. Moreover, the learned models are analyzed by the proposed sensitivity analysis revealing biologically plausible effects as well as confounding factors of the considered tasks. Thus, this study may serve as a starting point for further development of deep learning approaches in IMS classification tasks. https://gitlab.informatik.uni-bremen.de/digipath/Deep_Learning_for_Tumor_Classification_in_IMS. jbehrmann@uni-bremen.de, christianetmann@uni-bremen.de. Supplementary data are available at Bioinformatics online.

  12. Characterisation of the volatile profiles of infant formulas by proton transfer reaction-mass spectrometry and gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Ruth, van S.M.; Floris, V.; Fayoux, S.

    2006-01-01

    The volatile profiles of 13 infant formulas were evaluated by proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography¿mass spectrometry (GC¿MS). The infant formulas varied in brand (Aptamil, Cow & Gate, SMA), type (for different infant target groups) and physical form

  13. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  14. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  15. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  16. Atmospheric-Pressure Chemical Ionization Tandem Mass Spectrometry (APGC/MS/MS) an Alternative to High-Resolution Mass Spectrometry (HRGC/HRMS) for the Determination of Dioxins

    NARCIS (Netherlands)

    Bavel, Van Bert; Geng, Dawei; Cherta, Laura; Nácher-Mestre, Jaime; Portolés, Tania; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; Dunstan, Jody; Jones, Rhys; Kotz, Alexander; Winterhalter, Helmut; Malisch, Rainer; Traag, Wim; Hagberg, Jessika; Ericson Jogsten, Ingrid; Beltran, Joaquim; Hernández, Félix

    2015-01-01

    The use of a new atmospheric-pressure chemical ionization source for gas chromatography (APGC) coupled with a tandem quadrupole mass spectrometry (MS/MS) system, as an alternative to high-resolution mass spectrometry (HRMS), for the determination of PCDDs/PCDFs is described. The potential of

  17. Analysis of [U-13C6]glucose in human plasma using liquid chromatography/isotope ratio mass spectrometry compared with two other mass spectrometry techniques

    NARCIS (Netherlands)

    Schierbeek, H.; Moerdijk-Poortvliet, T.C.W.; van den Akker, C.H.P.; te Braake, F.W.J.; Boschker, H.T.S.; van Goudoever, J.B.

    2009-01-01

    The use of stable isotope labelled glucose provides insight into glucose metabolism. The 13C-isotopic enrichment of glucose is usually measured by gas chromatography/mass spectrometry (GC/MS) or gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). However, in both techniques

  18. Dehydrodimerization of pterostilbene during electrospray ionization mass spectrometry

    KAUST Repository

    Raji, Misjudeen

    2013-04-30

    RATIONALE Pterostilbene is a member of the hydroxystilbene family of compounds commonly found in plants such as blueberry and grapes. During the analysis of this compound by electrospray ionization mass spectrometry (ESI-MS), an ion was observed that corresponds to the dehydrodimer of pterostilbene in mass-to-charge ratio. Since such unexpected dimerization may lead to decreased monomer signal during quantitative analysis, it was of interest to identify the origin and structure of the observed pterostilbene dimer and examine the experimental conditions that influence its formation. METHODS Liquid Chromatography/Mass Spectrometry (LC/MS), Nuclear Magnetic Resonance (NMR), and High-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) were used to examine the origin of the dimerization products. The structure of the formed pterostilbene dimer was examined by performing MSn analysis on the dimer ion. Effects of solvent composition, analyte concentration, radical scavenger, and other experimental conditions on the dimerization were also studied. RESULTS LC/MS and NMR analyses clearly showed that the starting solution did not contain the pterostilbene dimer. Solvent type and radical scavenger concentration were found to have pronounced effects on the dimer formation. Particularly, presence of acetonitrile or ammonium acetate had favorable effects on the extent of dimerization during ESI-MS analysis whereas hydroquinone and butylated hydroquinone had negative effects. Dimer formation decreased at high flow rates and when fused-silica capillary was used as the spray needle. CONCLUSIONS The data indicate that this dimerization occurs as a result of solution-phase electrochemical reactions taking place during the electrospray process. A possible structure for this dimer was proposed based on the MSn analysis and was similar to that of the enzymatically derived pterostilbene dehydrodimer already reported in the literature. Copyright © 2013 John Wiley & Sons, Ltd

  19. Future Directions of Structural Mass Spectrometry using Hydroxyl Radical Footprinting

    Energy Technology Data Exchange (ETDEWEB)

    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

  20. Vaporization Studies of Olivine via Knudsen Effusion Mass Spectrometry

    Science.gov (United States)

    Costa, G. C. C.; Jacobson, N. S.

    2014-01-01

    Olivine is the major mineral in the Earth's upper mantle occurring predominantly in igneous rocks and has been identified in meteorites, asteroids, the Moon and Mars. Among many other important applications in planetary and materials sciences, the thermodynamic properties of vapor species from olivine are crucial as input parameters in computational modelling of the atmospheres of hot, rocky exoplanets (lava planets). There are several weight loss studies of olivine vaporization in the literature and one Knudsen Effusion Mass Spectrometry (KEMS) study. In this study, we examine a forsterite-rich olivine (93% forsterite and 7% fayalite, Fo93Fa7) with KEMS to further understand its vaporization and thermodynamic properties.

  1. Monitoring of wine aging process by electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    Alexandra Christine Helena Frankland Sawaya

    2011-09-01

    Full Text Available The characterization of wine samples by direct insertion electrospray ionization mass spectrometry (ESI-MS, without pre-treatment or chromatographic separation, in a process denominated fingerprinting, has been applied to several samples of wine produced with grapes of the Pinot noir, Merlot and Cabernet Sauvignon varieties from the state o Rio Grande do Sul, in Brazil. The ESI-MS fingerprints of the samples detected changes which occurred during the aging process in the three grape varieties. Principal Component Analysis (PCA of the negative ion mode fingerprints was used to group the samples, pinpoint the main changes in their composition, and indicate marker ions for each group of samples.

  2. Analytical strategies in mass spectrometry-based phosphoproteomics

    DEFF Research Database (Denmark)

    Rosenqvist, Heidi; Ye, Juanying; Jensen, Ole N

    2011-01-01

    to reveal key regulatory events and phosphorylation-mediated processes in the cell and in whole organisms. We present an overview of sensitive and robust analytical methods for phosphopeptide analysis, including calcium phosphate precipitation and affinity enrichment methods such as IMAC and TiO(2). We...... then discuss various tandem mass spectrometry approaches for phosphopeptide sequencing and quantification, and we consider aspects of phosphoproteome data analysis and interpretation. Efficient integration of these stages of phosphoproteome analysis is highly important to ensure a successful outcome of large...

  3. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry

    Science.gov (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.

    2017-10-01

    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  4. Application of accelerator mass spectrometry in aluminum metabolism studies

    Science.gov (United States)

    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.

  5. Imaging mass spectrometry tackles interfacial challenges in electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao-Ying

    2017-12-01

    Electrochemistry has played a significant role in many research fields. Owing to its sensitivity and selectivity, in situ electroanalysis has been widely used as a fast and economical means for achieving outstanding results. Although many spectroscopic techniques have been used in electrochemistry, the challenges to capture short-lived intermediate species as a result of electron transfer in the buried solid electrode and electrolyte solution interface remains a grand challenge. In situ imaging mass spectrometry (IMS) recently has been extended to capture transient species in electrochemistry. This review intends to summarize newest development of IMS and its applications in advancing fundamental electrochemistry.

  6. Solid support resins and affinity purification mass spectrometry.

    Science.gov (United States)

    Havis, Spencer; Moree, Wilna J; Mali, Sujina; Bark, Steven J

    2017-02-28

    Co-affinity purification-mass spectrometry (CoAP-MS) is a primary technology for elucidating the protein-protein interactions that form the basis of all biological processes. A critical component of CoAP-MS is the affinity purification (AP) of the bait protein, usually by immobilization of an antibody to a solid-phase resin. This Minireview discusses common resins, reagents, tagging methods, and their consideration for successful AP of tagged proteins. We discuss our experiences with different solid supports, their impact in AP experiments, and propose areas where chemistry can advance this important technology.

  7. Multinozzle emitter arrays for ultrahigh-throughput nanoelectrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-10-17

    The present invention provides for a structure comprising a plurality of emitters, wherein a first nozzle of a first emitter and a second nozzle of a second emitter emit in two directions that are not or essentially not in the same direction; wherein the walls of the nozzles and the emitters form a monolithic whole. The present invention also provides for a structure comprising an emitter with a sharpened end from which the emitter emits; wherein the emitters forms a monolithic whole. The present invention also provides for a fully integrated separation of proteins and small molecules on a silicon chip before the electrospray mass spectrometry analysis.

  8. Clusters of Monoisotopic Elements for Calibration in (TOF) Mass Spectrometry

    Science.gov (United States)

    Kolářová, Lenka; Prokeš, Lubomír; Kučera, Lukáš; Hampl, Aleš; Peňa-Méndez, Eladia; Vaňhara, Petr; Havel, Josef

    2017-03-01

    Precise calibration in TOF MS requires suitable and reliable standards, which are not always available for high masses. We evaluated inorganic clusters of the monoisotopic elements gold and phosphorus (Au n +/Au n - and P n +/P n -) as an alternative to peptides or proteins for the external and internal calibration of mass spectra in various experimental and instrumental scenarios. Monoisotopic gold or phosphorus clusters can be easily generated in situ from suitable precursors by laser desorption/ionization (LDI) or matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Their use offers numerous advantages, including simplicity of preparation, biological inertness, and exact mass determination even at lower mass resolution. We used citrate-stabilized gold nanoparticles to generate gold calibration clusters, and red phosphorus powder to generate phosphorus clusters. Both elements can be added to samples to perform internal calibration up to mass-to-charge ( m/z) 10-15,000 without significantly interfering with the analyte. We demonstrated the use of the gold and phosphorous clusters in the MS analysis of complex biological samples, including microbial standards and total extracts of mouse embryonic fibroblasts. We believe that clusters of monoisotopic elements could be used as generally applicable calibrants for complex biological samples.

  9. Clusters of Monoisotopic Elements for Calibration in (TOF) Mass Spectrometry.

    Science.gov (United States)

    Kolářová, Lenka; Prokeš, Lubomír; Kučera, Lukáš; Hampl, Aleš; Peňa-Méndez, Eladia; Vaňhara, Petr; Havel, Josef

    2017-03-01

    Precise calibration in TOF MS requires suitable and reliable standards, which are not always available for high masses. We evaluated inorganic clusters of the monoisotopic elements gold and phosphorus (Au n+/Au n- and P n+/P n-) as an alternative to peptides or proteins for the external and internal calibration of mass spectra in various experimental and instrumental scenarios. Monoisotopic gold or phosphorus clusters can be easily generated in situ from suitable precursors by laser desorption/ionization (LDI) or matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Their use offers numerous advantages, including simplicity of preparation, biological inertness, and exact mass determination even at lower mass resolution. We used citrate-stabilized gold nanoparticles to generate gold calibration clusters, and red phosphorus powder to generate phosphorus clusters. Both elements can be added to samples to perform internal calibration up to mass-to-charge (m/z) 10-15,000 without significantly interfering with the analyte. We demonstrated the use of the gold and phosphorous clusters in the MS analysis of complex biological samples, including microbial standards and total extracts of mouse embryonic fibroblasts. We believe that clusters of monoisotopic elements could be used as generally applicable calibrants for complex biological samples. Graphical Abstract ᅟ.

  10. Microdroplet fusion mass spectrometry for fast reaction kinetics.

    Science.gov (United States)

    Lee, Jae Kyoo; Kim, Samuel; Nam, Hong Gil; Zare, Richard N

    2015-03-31

    We investigated the fusion of high-speed liquid droplets as a way to record the kinetics of liquid-phase chemical reactions on the order of microseconds. Two streams of micrometer-size droplets collide with one another. The droplets that fused (13 μm in diameter) at the intersection of the two streams entered the heated capillary inlet of a mass spectrometer. The mass spectrum was recorded as a function of the distance x between the mass spectrometer inlet and the droplet fusion center. Fused droplet trajectories were imaged with a high-speed camera, revealing that the droplet fusion occurred approximately within a 500-μm radius from the droplet fusion center and both the size and the speed of the fused droplets remained relatively constant as they traveled from the droplet fusion center to the mass spectrometer inlet. Evidence is presented that the reaction effectively stops upon entering the heated inlet of the mass spectrometer. Thus, the reaction time was proportional to x and could be measured and manipulated by controlling the distance x. Kinetic studies were carried out in fused water droplets for acid-induced unfolding of cytochrome c and hydrogen-deuterium exchange in bradykinin. The kinetics of the former revealed the slowing of the unfolding rates at the early stage of the reaction within 50 μs. The hydrogen-deuterium exchange revealed the existence of two distinct populations with fast and slow exchange rates. These studies demonstrated the power of this technique to detect reaction intermediates in fused liquid droplets with microsecond temporal resolution.

  11. Tandem mass spectrometry data quality assessment by self-convolution

    Directory of Open Access Journals (Sweden)

    Tham Wai

    2007-09-01

    Full Text Available Abstract Background Many algorithms have been developed for deciphering the tandem mass spectrometry (MS data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. Results The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. Conclusion We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the

  12. Evaluation of Mass Filtered, Time Dilated, Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    2010-01-01

    spectrometry and this thesis evaluates the utility of a Pretzel magnet as an improved mass analyzer. Skoog et al. (2007) present a more complete view of...isotopic systems and geochronology in mineral systems. Australian Journal of Earth Sciences 49: 601-611. SKOOG , D., F.J. HOLLER, AND S.R. CROUCH

  13. Theory and technique of spark source mass spectrometry; Theorie et technique de la spectrometrie de masse a etincelles

    Energy Technology Data Exchange (ETDEWEB)

    Stefani, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    Trace analysis in solids by spark source mass spectrometry involves complicated phenomena: element ionization in spark and blacking of sensitive emulsion by focused ion beam. However the principal risk of selectivity lies in analyser system, which realizes double focusing only for a part of the ions. Therefore, each analyst has to known ionic optics of his apparatus, for ensuring the transmission of mean energetic ions, which are representative of sample composition. By a careful photometry of mass spectrum, good reproducibility can be obtained. Thereafter accuracy depends on the knowledge of sensitivity coefficients proper to this apparatus. (author) [French] L'analyse de traces dans les solides par spectrometrie de masse a etincelles met en jeu des phenomenes complexes qui sont l'ionisation des elements dans l'etincelle, et le noircissement de l'emulsion sensible par les faisceaux ioniques focalises. Cependant, le risque majeur de selectivite provient de l'ensemble analyseur, qui realise la double focalisation sur une fraction seulement du faisceau d'ions. L'analyste doit donc connaitre en detail l'optique ionique de son appareil, pour assurer le passage de la bande d'energie moyenne des ions, qui seule caracterise quantitativement la composition chimique de l'echantillon. Une exploitation photometrique soignee du spectrogramme donne alors des resultats reproductibles, dont la justesse ne depend plus que des coefficients de sensibilite propres a ce type d'instrument. (auteur)

  14. Sequencing of Oligourea Foldamers by Tandem Mass Spectrometry

    Science.gov (United States)

    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.

  15. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Viktor Johánek

    2016-01-01

    Full Text Available The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc. on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed subjected to a wide range of conditions.

  16. Use of mass spectrometry to study signaling pathways

    DEFF Research Database (Denmark)

    Pandey, A; Andersen, Jens S.; Mann, M

    2000-01-01

    Activation of cells by extracellular stimuli, such as growth factors, initiates a cascade of events involving posttranslational modifications, including phosphorylation, formation of protein complexes, and induction or repression of gene expression. Traditionally, genetic methods or specific...... biochemical assays have been used to identify molecules involved in signaling pathways. Lately, mass spectrometry, combined with elegant biochemical approaches, has become a powerful tool for identifying proteins and posttranslational modifications. With this protocol, we hope to bridge the gap between...... the biochemical and molecular aspects of signal transduction pathways and the mass spectrometric tools and techniques that are available to study them. We provide methods for large-scale cell culture and immunoprecipitation of tyrosine-phosphorylated proteins, silver staining of gels, trypsin digests, and protein...

  17. Differential Rapid Screening of Phytochemicals by Leaf Spray Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Thomas; Graham Cooks, R. [Univ. of Innsbruck, Innsbruck (Austria)

    2014-03-15

    Ambient ionization can be achieved by generating an electrospray directly from plant tissue ('leaf spray'). The resulting mass spectra are characteristic of ionizable phytochemicals in the plant material. By subtracting the leaf spray spectra recorded from the petals of two hibiscus species H. moscheutos and H. syriacus one gains rapid access to the metabolites that differ most in the two petals. One such compound was identified as the sambubioside of quercitin (or delphinidin) while others are known flavones. Major interest centered on a C{sub 19}H{sub 29}NO{sub 5} compound that occurs only in the large H. moscheutos bloom. Attempts were made to characterize this compound by mass spectrometry alone as a test of such an approach. This showed that the compound is an alkaloid, assigned to the polyhydroxylated pyrrolidine class, and bound via a C{sub 3} hydrocarbon unit to a monoterpene.

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

    DEFF Research Database (Denmark)

    Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias

    2016-01-01

    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...... 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......-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. Graphical Abstract ᅟ....

  19. Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    Johánek, Viktor; Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

    2016-01-01

    The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

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

    Science.gov (United States)

    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

  1. Improved quantitative analysis of mass spectrometry using quadratic equations.

    Science.gov (United States)

    Yoon, Joo Young; Lim, Kyung Young; Lee, Sunho; Park, Kunsoo; Paek, Eunok; Kang, Un-Beom; Yeom, Jeonghun; Lee, Cheolju

    2010-05-07

    Protein quantification is one of the principal computational problems in mass spectrometry (MS) based proteomics. For robust and trustworthy protein quantification, accurate peptide quantification must be preceded. In recent years, stable isotope labeling has become the most popular method for relative quantification of peptides. However, some stable isotope labeling methods may carry a critical problem, which is an overlap of isotopic clusters. If the mass difference between the light- and heavy-labeled peptides is very small, the overlap of their isotopic clusters becomes larger as the mass of original peptide increases. Here we propose a new algorithm for peptide quantification that separates overlapping isotopic clusters using quadratic equations. It can be easily applied in Trans-Proteomic Pipeline (TPP) instead of XPRESS. For the mTRAQ-labeled peptides obtained by an Orbitrap mass spectrometer, it showed more accurate ratios and better standard deviations than XPRESS. Especially, for the peptides that do not contain lysine, the ratio difference between XPRESS and our algorithm became larger as the peptide masses increased. We expect that this algorithm can also be applied to other labeling methods such as (18)O labeling and acrylamide labeling.

  2. Hydraulic Validation of the LHC Cold Mass Heat Exchanger Tube

    CERN Document Server

    Provenaz, P

    1998-01-01

    The knowledge of the helium mass flow vs. the fraction of the tube wetted by the liquid helium II in the heat exchanger is a crucial input parameter for the heat exchange since the heat flux is direct ly proportional to the wetted surface. In the range of liquid and gas velocities inside the heat exchanger, the liquid flow behaves like in an open channel. Looking at the flow equations for such a s ituation, the velocity depends on the fluid properties only by the friction factor which is a function of the Reynolds number. Thus it was decided to build an experiment with water in order to check t he open channel equations in the heat exchanger geometry. This paper shows the results for water and gives the extrapolation for helium.

  3. Bead Separation and MALDI-TOF Mass Spectrometry Analysis

    Directory of Open Access Journals (Sweden)

    Nai-Jun Fan

    2012-01-01

    Full Text Available Background. Colorectal cancer (CRC is one of the most common cancers in the world, identification of biomarkers for early detection of CRC represents a relevant target. The present study aims to determine serum peptidome patterns for CRC diagnosis. Methods. The present work focused on serum proteomic analysis of 32 health volunteers and 38 CRC by ClinProt Kit combined with mass spectrometry. This approach allowed the construction of a peptide patterns able to differentiate the studied populations. An independent group of serum (including 33 health volunteers, 34 CRC, 16 colorectal adenoma, 36 esophageal carcinoma, and 31 gastric carcinoma samples was used to verify the diagnostic and differential diagnostic capability of the peptidome patterns blindly. An immunoassay method was used to determine serum CEA of CRC and controls. Results. A quick classifier algorithm was used to construct the peptidome patterns for identification of CRC from controls. Two of the identified peaks at m/z 741 and 7772 were used to construct peptidome patterns, achieving an accuracy close to 100% (>CEA, P<0.05. Furthermore, the peptidome patterns could differentiate validation group with high accuracy. Conclusions. These results suggest that the ClinProt Kit combined with mass spectrometry yields significantly higher accuracy for the diagnosis and differential diagnosis of CRC.

  4. Proof of the quantitative potential of immunofluorescence by mass spectrometry.

    Science.gov (United States)

    Toki, Maria I; Cecchi, Fabiola; Hembrough, Todd; Syrigos, Konstantinos N; Rimm, David L

    2017-03-01

    Protein expression in formalin-fixed, paraffin-embedded patient tissue is routinely measured by Immunohistochemistry (IHC). However, IHC has been shown to be subject to variability in sensitivity, specificity and reproducibility, and is generally, at best, considered semi-quantitative. Mass spectrometry (MS) is considered by many to be the criterion standard for protein measurement, offering high sensitivity, specificity, and objective molecular quantification. Here, we seek to show that quantitative immunofluorescence (QIF) with standardization can achieve quantitative results comparable to MS. Epidermal growth factor receptor (EGFR) was measured by quantitative immunofluorescence in 15 cell lines with a wide range of EGFR expression, using different primary antibody concentrations, including the optimal signal-to-noise concentration after quantitative titration. QIF target measurement was then compared to the absolute EGFR concentration measured by Liquid Tissue-selected reaction monitoring mass spectrometry. The best agreement between the two assays was found when the EGFR primary antibody was used at the optimal signal-to-noise concentration, revealing a strong linear regression (R 2 =0.88). This demonstrates that quantitative optimization of titration by calculation of signal-to-noise ratio allows QIF to be standardized to MS and can therefore be used to assess absolute protein concentration in a linear and reproducible manner.

  5. Analysis of hazardous biological material by MALDI mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    KL Wahl; KH Jarman; NB Valentine; MT Kingsley; CE Petersen; ST Cebula; AJ Saenz

    2000-03-21

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) has become a valuable tool for analyzing microorganisms. The speed with which data can be obtained from MALDI-MS makes this a potentially important tool for biological health hazard monitoring and forensic applications. The excitement in the mass spectrometry community in this potential field of application is evident by the expanding list of research laboratories pursuing development of MALDI-MS for bacterial identification. Numerous research groups have demonstrated the ability to obtain unique MALDI-MS spectra from intact bacterial cells and bacterial cell extracts. The ability to differentiate strains of the same species has been investigated. Reproducibility of MALDI-MS spectra from bacterial species under carefully controlled experimental conditions has also been demonstrated. Wang et al. have reported on interlaboratory reproducibility of the MALDI-MS analysis of several bacterial species. However, there are still issues that need to be addressed, including the careful control of experimental parameters for reproducible spectra and selection of optimal experimental parameters such as solvent and matrix.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ludvigson, Laura D. [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    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.

  7. Pesticide residues screening in wine by mass spectrometry

    Directory of Open Access Journals (Sweden)

    Machado Andrea F.

    2016-01-01

    Full Text Available Recently, a study (from PAN Europe covered 40 bottles of wine – 34 conventional and six organic ones – purchased inside the EU. According to the results, the 34 bottles of conventional wine together contained 148 pesticide residues. All 34 bottles contained from one to ten pesticides, bringing the average per bottle to more than four. Of the six bottles of organic wine tested, one sample contained a low concentration of a possibly carcinogenic pesticide. According to PAN Europe, the “contamination of wines is a direct result of over-reliance on pesticides in grape production”. This study, between others, to prove the importance of develop methods sensivity and confident for pesticide detection in wine. A multi-residue method was developed for the determination ca of 250 pesticide residues in wine using Quechers extraction, gas chromatography-tandem mass spectrometry (GC-MS-MS and liquid chromatography-tandem mass spectrometry (LC-MS-MS. The method was validated with the evaluation of follow parameters: Linearity, Precision, Accuracy, Matrix effect, Limit of detection and Limit of Quantification. The method was approved and was able to quantify pesticide residues in more than 60 samples of wine.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Secondary ionization mass spectrometry analysis in petrochronology: Chapter 7

    Science.gov (United States)

    Schmitt, Axel K.; Vazquez, Jorge A.

    2017-01-01

    The goal of petrochronology is to extract information about the rates and conditions at which rocks and magmas are transported through the Earth’s crust. Garnering this information from the rock record greatly benefits from integrating textural and compositional data with radiometric dating of accessory minerals. Length scales of crystal growth and diffusive transport in accessory minerals under realistic geologic conditions are typically in the range of 1–10’s of μm, and in some cases even substantially smaller, with zircon having among the lowest diffusion coefficients at a given temperature (e.g., Cherniak and Watson 2003). Intrinsic to the compartmentalization of geochemical and geochronologic information from intra-crystal domains is the requirement to determine accessory mineral compositions using techniques that sample at commensurate spatial scales so as to not convolute the geologic signals that are recorded within crystals, as may be the case with single grain or large grain fragment analysis by isotope dilution thermal ionization mass spectrometry (ID-TIMS; e.g., Schaltegger and Davies 2017, this volume; Schoene and Baxter 2017, this volume). Small crystals can also be difficult to extract by mineral separation techniques traditionally used in geochronology, which also lead to a loss of petrographic context. Secondary Ionization Mass Spectrometry, that is SIMS performed with an ion microprobe, is an analytical technique ideally suited to meet the high spatial resolution analysis requirements that are critical for petrochronology (Table 1).

  10. NMR and mass spectrometry of phosphorus in wetlands

    Science.gov (United States)

    El-Rifai, H.; Heerboth, M.; Gedris, T.E.; Newman, S.; Orem, W.; Cooper, W.T.

    2008-01-01

    There is at present little information on the long-term stability of phosphorus sequestered in wetlands. Phosphorus sequestered during high loading periods may be relatively unstable and easily remobilized following changes in nutrient status or hydrological regime, but the chemical forms of sequestered phosphorus that do remobilize are largely unknown at this time. A lack of suitable analytical techniques has contributed to this dearth of knowledge regarding the stability of soil organic phosphorus. We analysed phosphorus in soils from the 'head' of Rescue Strand tree island and an adjacent marsh in the Florida Everglades by 31P nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Tree islands are important areas of biodiversity within the Everglades and offer a unique opportunity to study phosphorus sequestration because they are exposed to large phosphorus loads and appear to be natural nutrient sinks. The 31P NMR profiling of extracts from surface and sediment samples in the tree island indicates that phosphorus input to Rescue Strand tree island soils is mostly in the form of inorganic ortho-phosphate and is either refractory when deposited or rapidly recycled by the native vegetation into a stable phosphorus pool largely resistant to re-utilization by plants or microbes. Mass spectrometry revealed the presence of inositol hexakisphosphate, a common organic monophosphate ester not previously observed in Everglades' soils. ?? 2008 The Authors.

  11. Expanded newborn screening by mass spectrometry: New tests, future perspectives.

    Science.gov (United States)

    Ombrone, Daniela; Giocaliere, Elisa; Forni, Giulia; Malvagia, Sabrina; la Marca, Giancarlo

    2016-01-01

    Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs. © 2015 Wiley Periodicals, Inc.

  12. Optimal selection of epitopes for TXP-immunoaffinity mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joos Thomas

    2010-06-01

    Full Text Available Abstract Background Mass spectrometry (MS based protein profiling has become one of the key technologies in biomedical research and biomarker discovery. One bottleneck in MS-based protein analysis is sample preparation and an efficient fractionation step to reduce the complexity of the biological samples, which are too complex to be analyzed directly with MS. Sample preparation strategies that reduce the complexity of tryptic digests by using immunoaffinity based methods have shown to lead to a substantial increase in throughput and sensitivity in the proteomic mass spectrometry approach. The limitation of using such immunoaffinity-based approaches is the availability of the appropriate peptide specific capture antibodies. Recent developments in these approaches, where subsets of peptides with short identical terminal sequences can be enriched using antibodies directed against short terminal epitopes, promise a significant gain in efficiency. Results We show that the minimal set of terminal epitopes for the coverage of a target protein list can be found by the formulation as a set cover problem, preceded by a filtering pipeline for the exclusion of peptides and target epitopes with undesirable properties. Conclusions For small datasets (a few hundred proteins it is possible to solve the problem to optimality with moderate computational effort using commercial or free solvers. Larger datasets, like full proteomes require the use of heuristics.

  13. Use of Tritium Accelerator Mass Spectrometry for Tree Ring Analysis

    Science.gov (United States)

    LOVE, ADAM H.; HUNT, JAMES R.; ROBERTS, MARK L.; SOUTHON, JOHN R.; CHIARAPPA - ZUCCA, MARINA L.; DINGLEY, KAREN H.

    2010-01-01

    Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may contain the only historical record of tritium exposure. The tritium activity in the annual rings of a tree was measured using accelerator mass spectrometry to reconstruct historical annual averages of tritium exposure. Milligram-sized samples of the annual tree rings from a Tamarix located at the Nevada Test Site are used for validation of this methodology. The salt cedar was chosen since it had a single source of tritiated water that was well-characterized as it varied over time. The decay-corrected tritium activity of the water in which the salt cedar grew closely agrees with the organically bound tritium activity in its annual rings. This demonstrates that the milligram-sized samples used in tritium accelerator mass spectrometry are suited for reconstructing anthropogenic tritium levels in the environment. PMID:12144257

  14. Isotope determination of sulfur by mass spectrometry in soil samples

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete

    2012-12-01

    Full Text Available Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-, which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2- concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms was carried out by isotope ratio mass spectrometry (IRMS. In this work, the labeled material (K2(34SO4 was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.

  15. Statistical analysis of proteomics, metabolomics, and lipidomics data using mass spectrometry

    CERN Document Server

    Mertens, Bart

    2017-01-01

    This book presents an overview of computational and statistical design and analysis of mass spectrometry-based proteomics, metabolomics, and lipidomics data. This contributed volume provides an introduction to the special aspects of statistical design and analysis with mass spectrometry data for the new omic sciences. The text discusses common aspects of design and analysis between and across all (or most) forms of mass spectrometry, while also providing special examples of application with the most common forms of mass spectrometry. Also covered are applications of computational mass spectrometry not only in clinical study but also in the interpretation of omics data in plant biology studies. Omics research fields are expected to revolutionize biomolecular research by the ability to simultaneously profile many compounds within either patient blood, urine, tissue, or other biological samples. Mass spectrometry is one of the key analytical techniques used in these new omic sciences. Liquid chromatography mass ...

  16. Selenosugar determination in porcine liver using multidimensional HPLC with atomic and molecular mass spectrometry.

    Science.gov (United States)

    Lu, Ying; Pergantis, Spiros A

    2009-01-01

    A methodology based on liquid chromatography coupled online with atomic and molecular mass spectrometry was developed for identifying trace amounts of the selenosugar methyl 2-acetamido-2-deoxy-1-seleno-β-D-galactopyranoside (SeGalNAc) in porcine liver, obtained from an animal that had not received selenium supplementation. Sample preparation was especially critical for the identification of SeGalNAc by molecular mass spectrometry. This involved liver extraction using a Tris buffer, followed by sequential centrifugations. The resulting cytosolic fraction was pre-concentrated and the low molecular weight selenium (LMWSe) fraction obtained from a size exclusion column was collected, concentrated, and subsequently analyzed using a tandem dual-column HPLC-ICP-MS system which consisted of strong cation exchange (SCX) and reversed phase (RP) columns coupled in tandem. Hepatocytosolic SeGalNAc was tentatively identified by retention time matching and spiking. Its identity was further confirmed by using the same type of chromatography on-line with atmospheric pressure chemical ionization tandem mass spectrometry operated in the selected reaction monitoring (SRM) mode. Four SRM transitions, characteristic of SeGalNAc, were monitored and their intensity ratios determined in order to confirm SeGalNAc identification. Instrument limits of detection for SeGalNAc by SCX-RP HPLC-ICP-MS and SCX-RP HPLC-APCI-MS/MS were 3.4 and 2.9 μg Se L(-1), respectively. Selenium mass balance analysis revealed that trace amounts of SeGalNAc, 2.16±0.94 μg Se kg(-1) liver (wet weight) were present in the liver cytosol, corresponding to 0.4% of the total Se content in the porcine liver.

  17. Elucidation of the mass fragmentation pathways of potato glycoalkaloids and aglycons using Orbitrap mass spectrometry.

    Science.gov (United States)

    Cahill, Michael G; Caprioli, Giovanni; Vittori, Sauro; James, Kevin J

    2010-09-01

    The mass fragmentation of potato glycoalkaloids, α-solanine and α-chaconine, and the aglycons, demissidine and solasodine were studied using the Orbitrap Fourier transform (FT) mass spectrometer. Using the linear ion trap (LIT) mass spectrometry, multistage collisional-induced dissociation (CID) experiments (MS(n)) on the [M + H](+) precursor ions were performed to aid the elucidation of the mass fragmentation pathways. In addition, higher energy collisional-induced dissociation (HCD) mass spectra were generated for these toxins at a high resolution setting [100,000 FWHM (full width at half maximum)] using the Orbitrap. This hybrid mass spectrometry instrumentation was exploited to produce MS(3) spectra by selecting MS(2) product ions, generated using LIT MS, and fragmentation using HCD. The accurate mass data in the MS(3) spectra aided the confirmation of proposed product ion formulae. The precursor and product ions from glycoalkaloids lost up to four sugars from different regions during MS(n) experiments. Mass fragmentation of the six-ring aglycons were similar, generating major product ions that resulted from cleavages at the B-rings and E-rings. 2010 John Wiley & Sons, Ltd.

  18. Ion Mobility Spectrometry - High Resolution LTQ-Orbitrap Mass Spectrometry for Analysis of Homemade Explosives

    Science.gov (United States)

    Hagan, Nathan; Goldberg, Ilana; Graichen, Adam; St. Jean, Amanda; Wu, Ching; Lawrence, David; Demirev, Plamen

    2017-08-01

    The detailed chemical characterization of homemade explosives (HMEs) and other chemicals that can mimic or mask the presence of explosives is important for understanding and improving the performance of commercial instrumentation used for explosive detection. To that end, an atmospheric-pressure drift tube ion mobility spectrometry (IMS) instrument has been successfully coupled to a commercial tandem mass spectrometry (MS) system. The tandem MS system is comprised of a linear ion trap and a high resolution Orbitrap analyzer. This IMS-MS combination allows extensive characterization of threat chemical compounds, including HMEs, and complex real-world background chemicals that can interfere with detection. Here, the composition of ion species originating from a specific HME, erythritol tetranitrate, has been elucidated using accurate mass measurements, isotopic ratios, and tandem MS. Gated IMS-MS and high-resolution MS have been used to identify minor impurities that can be indicative of the HME source and/or synthesis route. Comparison between data obtained on the IMS/MS system and on commercial stand-alone IMS instruments used as explosive trace detectors (ETDs) has also been performed. Such analysis allows better signature assignments of threat compounds, modified detection algorithms, and improved overall ETD performance.

  19. Simultaneous Proteomic Discovery and Targeted Monitoring using Liquid Chromatography, Ion Mobility Spectrometry, and Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Burnum-Johnson, Kristin E.; Nie, Song; Casey, Cameron P.; Monroe, Matthew E.; Orton, Daniel J.; Ibrahim, Yehia M.; Gritsenko, Marina A.; Clauss, Therese R. W.; Shukla, Anil K.; Moore, Ronald J.; Purvine, Samuel O.; Shi, Tujin; Qian, Weijun; Liu, Tao; Baker, Erin S.; Smith, Richard D.

    2016-09-25

    Current proteomics approaches are comprised of both broad discovery measurements as well as more quantitative targeted measurements. These two different measurement types are used to initially identify potentially important proteins (e.g., candidate biomarkers) and then enable improved quantification for a limited number of selected proteins. However, both approaches suffer from limitations, particularly the lower sensitivity, accuracy, and quantitation precision for discovery approaches compared to targeted approaches, and the limited proteome coverage provided by targeted approaches. Herein, we describe a new proteomics approach that allows both discovery and targeted monitoring (DTM) in a single analysis using liquid chromatography, ion mobility spectrometry and mass spectrometry (LC-IMS-MS). In DTM, heavy labeled peptides for target ions are spiked into tryptic digests and both the labeled and unlabeled peptides are broadly detected using LC-IMS-MS instrumentation, allowing the benefits of discovery and targeted approaches. To understand the possible improvement of the DTM approach, it was compared to LC-MS broad measurements using an accurate mass and time tag database and selected reaction monitoring (SRM) targeted measurements. The DTM results yielded greater peptide/protein coverage and a significant improvement in the detection of lower abundance species compared to LC-MS discovery measurements. DTM was also observed to have similar detection limits as SRM for the targeted measurements indicating its potential for combining the discovery and targeted approaches.

  20. Proton transfer reaction-mass spectrometry applications in medical research.

    Science.gov (United States)

    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

  1. Method for predicting peptide detection in mass spectrometry

    Science.gov (United States)

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA

    2010-07-13

    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  2. Time-of-flight mass spectrometry: Introduction to the basics.

    Science.gov (United States)

    Boesl, Ulrich

    2017-01-01

    The intention of this tutorial is to introduce into the basic concepts of time-of-flight mass spectrometry, beginning with the most simple single-stage ion source with linear field-free drift region and continuing with two-stage ion sources combined with field-free drift regions and ion reflectors-the so-called reflectrons. Basic formulas are presented and discussed with the focus on understanding the physical relations of geometric and electric parameters, initial distribution of ionic parameters, ion flight times, and ion flight time incertitude. This tutorial is aimed to help the applicant to identify sources of flight time broadening which limit good mass resolution and sources of ion losses which limit sensitivity; it is aimed to stimulate creativity for new experimental approaches by discussing a choice of instrumental options and to encourage those who toy with the idea to build an own time-of-flight mass spectrometer. Large parts of mathematics are shifted into a separate chapter in order not to overburden the text with too many mathematical deviations. Rather, thumb-rule formulas are supplied for first estimations of geometry and potentials when designing a home-built instrument, planning experiments, or searching for sources of flight time broadening. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:86-109, 2017. © 2016 Wiley Periodicals, Inc.

  3. Characterization of low-molecular weight iodine-terminated polyethylenes by gas chromatography/mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with the use of derivatization.

    Science.gov (United States)

    Zaikin, Vladimir G; Borisov, Roman S; Polovkov, Nikolai Yu; Zhilyaev, Dmitry I; Vinogradov, Aleksei A; Ivanyuk, Aleksei V

    2013-01-01

    Gas chromatography/mass spectrometry (GC/MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry, in conjunction with various derivatization approaches, have been applied to structure determination of individual oligomers and molecular-mass distributions (MMD) in low-molecular mass polyethylene having an iodine terminus. Direct GC/MS analysis has shown that the samples under investigation composed of polyethyelene-iodides (major components) and n-alkanes. Exchange reaction with methanol in the presence of NaOH gave rise to methoxy-derivatives and n-alkenes. Electron ionization mass spectra have shown that the former contained terminal methoxy groups indicating the terminal position of the iodine atom in the initial oligomers. MMD parameters have been determined with the aid of MALDI mass spectrometry followed by preliminary derivatization-formation of covalently bonded charge through the reaction of iodides with triphenylphosphine, trialkylamines, pyridine or quinoline. The mass spectra revealed well-resolved peaks for cationic parts of derivatized oligomers allowing the determination of MMD. The latter values have been compared with those calculated from GC/MS data.

  4. Mass spectrometry in the pharmacokinetic studies of anticancer natural products.

    Science.gov (United States)

    Crotti, Sara; Posocco, Bianca; Marangon, Elena; Nitti, Donato; Toffoli, Giuseppe; Agostini, Marco

    2017-03-01

    In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry-based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre-analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213-251, 2017. © 2015 Wiley Periodicals, Inc.

  5. Screening Non-colored Phenolics in Red Wines using Liquid Chromatography/Ultraviolet and Mass Spectrometry/Mass Spectrometry Libraries

    Directory of Open Access Journals (Sweden)

    Jianping Sun

    2007-03-01

    Full Text Available Liquid chromatography/ultraviolet (LC/UV and mass spectrometry/mass spectrometry (MS/MS libraries containing 39 phenolic compounds were established by coupling a LC and an ion trap MS with an electrospray ionization (ESI source, operated in negative ion mode. As a result, the deprotonated [M-H]- molecule was observed for all the analyzed compounds. Using MS/MS hydroxybenzoic acid and hydroxycinnamic acids showed a loss of CO2 and production of a [M-H-44] - fragment and as expected, the UV spectra of these two compounds were affected by their chemical structures. For flavonol and flavonol glycosides, the spectra of their glycosides and aglycones produced deprotonated [M-H]- and [A-H]- species, respectively, and their UV spectra each presented two major absorption peaks. The UV spectra and MS/MS data of flavan-3-ols and stilbenes were also investigated. Using the optimized LC/MS/MS analytical conditions, the phenolic extracts from six representative wine samples were analyzed and 31 phenolic compounds were detected, 26 of which were identified by searching the LC/UV and MS/MS libraries. Finally, the presence of phenolic compounds was confirmed in different wine samples using the LC/UV and LC/MS/MS libraries.

  6. Chromatography and mass spectrometry of prebiological and biological molecules

    Science.gov (United States)

    Navale, Vivek

    The detection and identification of prebiological and biological molecules are of importance for understanding chemical and biological processes occurring within the solar system. Molecular mass measurements, peptide mapping, and disulfide bond analysis of enzymes and recombinant proteins are important in the development of therapeutic drugs for human diseases. Separation of hydrocarbons (C1 to C6) and nitriles was achieved by 14%-cyanopropylphenyl-86%- dimethylpolysiloxane (CPPS-DMPS) stationary phase in a narrow bore metal capillary column. The calculation of modeling numbers enabled the differentiation of the C4 hydrocarbon isomers of 1-butene (cis and trans). The modeled retention time values for benzene, toluene, xylene, acetonitrile, propane, and propene nitriles were in good agreement with the measurements. The separation of C2 hydrocarbons (ethane and ethene) from predominantly N2 matrix was demonstrated for the first time on wall coated narrow bore low temperature glassy carbon column. Identification and accurate mass measurements of pepsin, an enzymatic protein with less number of basic amino acid residues were successfully demonstrated by matrix- assisted laser desorption ionization mass spectrometry (MALDI-MS). The molecular mass of pepsin was found to be 34,787 Da. Several decomposition products of pepsin, in m/z range of 3,500 to 4,700 were identified. Trypsin, an important endopeptidase enzyme had a mass of 46829.7 Da. Lower mass components with m/z 8047.5, 7776.6, 5722, 5446.2 and 5185 Da were also observed in trypsin spectrum. Both chemokine and growth factor recombinant proteins were mass analyzed as 8848.1 ± 3.5 and 16178.52 ± 4.1 Da, respectively. The accuracy of the measurements was in the range of 0.01 to 0.02%. Reduction and alkylation experiments on the chemokine showed the presence of six cysteines and three disulfide bonds. The two cysteines of the growth factor contained the free sulfhydryl groups and the accurate average mass of the

  7. Direct Analysis in Real Time (DART of an Organothiophosphate at Ultrahigh Resolution by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Laszlo Prokai

    2016-01-01

    Full Text Available Direct analysis in real time (DART is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR mass spectrometry (MS and tandem mass spectrometry (MS/MS. Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae.

  8. Liquid extraction surface analysis field asymmetric waveform ion mobility spectrometry mass spectrometry for the analysis of dried blood spots.

    Science.gov (United States)

    Griffiths, Rian L; Dexter, Alex; Creese, Andrew J; Cooper, Helen J

    2015-10-21

    Liquid extraction surface analysis (LESA) is a surface sampling technique that allows electrospray mass spectrometry analysis of a wide range of analytes directly from biological substrates. Here, we present LESA mass spectrometry coupled with high field asymmetric waveform ion mobility spectrometry (FAIMS) for the analysis of dried blood spots on filter paper. Incorporation of FAIMS in the workflow enables gas-phase separation of lipid and protein molecular classes, enabling analysis of both haemoglobin and a range of lipids (phosphatidylcholine or phosphatidylethanolamine, and sphingomyelin species) from a single extraction sample. The work has implications for multiplexed clinical assays of multiple analytes.

  9. Isotope effects in mass-spectrometry; Les effets isotopiques en spectrometrie de masse

    Energy Technology Data Exchange (ETDEWEB)

    Leicknam, J.P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement de physico-chimie, service des isotopes stables, section de spectrometrie de masse

    1967-05-01

    In the first part, a review is made of the work concerning the influence of isotopic substitution on the stabilities of ionised molecules and the bond-breaking probabilities; metastable transitions are also affected by this substitution. A model based on the Franck-Condon principle accounts for the experimentally observed isotopic effects for diatomic molecules; to a certain extent it is possible to generalise the calculation for the case of isotopic molecules of carbon dioxide gas. For deuterated polyatomic molecules there exist a {pi} effect making it possible to compare the relative stabilities of the X-H and X-D bonds, and a {gamma} effect which characterizes the different behaviours of the X-H bond in a normal molecule and in its partially deuterated homologue. Usually there is a very marked {pi} effect (e.g. the C-D bonds are more difficult to break than the homologous C-H bonds) and a {gamma} effect, the partial deuteration of a molecule leading in general to an increase in the probability of breakage of a given bond. An interpretation of {pi} and {gamma} effects based on Rosenstock near-equilibrium theory accounts for the observed phenomena, qualitatively at least, in the case of propane and acetylene. In the second part are gathered together results concerning isotopic effects produced during the formation of rearranged ions. The existence of cyclic transition ions has made it possible for Mc Lafferty to explain the existence of these ions in the mass spectrum; isotopic substitution leads to a modification of the rearrangement mechanism, the bonding forces being no longer the same. (author) [French] Dans une premiere partie, on rassemble les travaux concernant l'influence de la substitution isotopique sur les stabilites des molecules ionisees et les probabilites de rupture des liaisons; les transitions metastables sont egalement modifiees par cette substitution. Un modele base sur le principe de Franck-Condon rend compte des effets isotopiques

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

    Science.gov (United States)

    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

  11. Estimation of brassylic acid by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr

    2010-10-29

    The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

  12. Monitoring the synthesis of biomolecules using mass spectrometry.

    Science.gov (United States)

    Miyagi, Masaru; Kasumov, Takhar

    2016-10-28

    The controlled and selective synthesis/clearance of biomolecules is critical for most cellular processes. In most high-throughput 'omics' studies, we measure the static quantities of only one class of biomolecules (e.g. DNA, mRNA, proteins or metabolites). It is, however, important to recognize that biological systems are highly dynamic in which biomolecules are continuously renewed and different classes of biomolecules interact and affect each other's production/clearance. Therefore, it is necessary to measure the turnover of diverse classes of biomolecules to understand the dynamic nature of biological systems. Herein, we explain why the kinetic analysis of a diverse range of biomolecules is important and how such an analysis can be done. We argue that heavy water ((2)H2O) could be a universal tracer for monitoring the synthesis of biomolecules on a global scale.This article is part of the themed issue 'Quantitative mass spectrometry'. © 2016 The Author(s).

  13. Evaluating plant immunity using mass spectrometry-based metabolomics workflows

    Directory of Open Access Journals (Sweden)

    Adam L Heuberger

    2014-06-01

    Full Text Available Metabolic processes in plants are key components of physiological and biochemical disease resistance. Metabolomics, the analysis of a broad range of small molecule compounds in a biological system, has been used to provide a systems-wide overview of plant metabolism associated with defense responses. Plant immunity has been examined using multiple metabolomics workflows that vary in methods of detection, annotation, and interpretation, and the choice of workflow can significantly impact the conclusions inferred from a metabolomics investigation. The broad range of metabolites involved in plant defense often supports the need for multiple chemical detection platforms and implementation of a non-targeted approach. A review of the current literature reveals a wide range of workflows that are currently used in plant metabolomics, and new methods for analyzing and reporting mass spectrometry data can improve the ability to translate investigative findings among different plant-pathogen systems.

  14. High-Throughput Mass Spectrometry Applied to Structural Genomics

    Directory of Open Access Journals (Sweden)

    Rod Chalk

    2014-10-01

    Full Text Available Mass spectrometry (MS remains under-utilized for the analysis of expressed proteins because it is inaccessible to the non-specialist, and sample-turnaround from service labs is slow. Here, we describe 3.5 min Liquid-Chromatography (LC-MS and 16 min LC-MSMS methods which are tailored to validation and characterization of recombinant proteins in a high throughput structural biology pipeline. We illustrate the type and scope of MS data typically obtained from a 96-well expression and purification test for both soluble and integral membrane proteins (IMPs, and describe their utility in the selection of constructs for scale-up structural work, leading to cost and efficiency savings. We propose that value of MS data lies in how quickly it becomes available and that this can fundamentally change the way in which it is used.

  15. Chemical reaction interface mass spectrometry with high efficiency nebulization.

    Science.gov (United States)

    Jorabchi, Kaveh; Kahen, Kaveh; Lecchi, Paolo; Montaser, Akbar

    2005-08-15

    A high efficiency nebulizer (HEN) coupled to a heated spray chamber and a membrane desolvator is used for liquid sample introduction in chemical reaction interface mass spectrometry (CRIMS). Compared to the conventional thermospray nebulizer operated at solvent flow rate of 1 mL/min, the HEN provides small droplets at lower flow rates (10-100 microL/min), improving the desolvation and analyte transport efficiency. As a result, the sensitivity for carbon detection by CRIMS is improved by a factor of 4. The new arrangement offers an easy-to-use and robust interface, facilitating the availability of a variety of liquid chromatographic techniques to the CRIMS. Separation and detection of labeled peptides in a mixture of unlabeled biopolymers is illustrated at a solvent flow rate of 45 microL/min as an example of new possibilities offered by the improved liquid introduction interface.

  16. Centrosome isolation and analysis by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Jakobsen, Lis; Schrøder, Jacob Morville; Larsen, Katja M

    2013-01-01

    Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined with advan......Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined...... understood. Considering the complexity and dynamics of centriole-related proteomes and the first-pass analyses reported so far, it is likely that further insight might come from more thorough proteome analyses under various cellular and physiological conditions. To this end, we here describe methods...... to isolate centrosomes from human cells and strategies to selectively identify and study the properties of the associated proteins using quantitative mass spectrometry-based proteomics....

  17. Triacylglycerol profiling of marine microalgae by mass spectrometry.

    Science.gov (United States)

    Danielewicz, Megan A; Anderson, Lisa A; Franz, Annaliese K

    2011-11-01

    We present a method for the determination of triacylglycerol (TAG) profiles of oleaginous saltwater microalgae relevant for the production of biofuels, bioactive lipids, and high-value lipid-based chemical precursors. We describe a technique to remove chlorophyll using quick, simple solid phase extraction (SPE) and directly compare the intact TAG composition of four microalgae species (Phaeodactylum tricornutum, Nannochloropsis salina, Nannochloropsis oculata, and Tetraselmis suecica) using MALDI time-of-flight (TOF) mass spectrometry (MS), ESI linear ion trap-orbitrap (LTQ Orbitrap) MS, and ¹H NMR spectroscopy. Direct MS analysis is particularly effective to compare the polyunsaturated fatty acid (PUFA) composition for triacylglycerols because oxidation can often degrade samples upon derivatization. Using these methods, we observed that T. suecica contains significant PUFA levels with respect to other microalgae. This method is applicable for high-throughput MS screening of microalgae TAG profiles and may aid in the commercial development of biofuels.

  18. Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E; Brown, T A

    2002-10-03

    A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.

  19. Metriculator: quality assessment for mass spectrometry-based proteomics.

    Science.gov (United States)

    Taylor, Ryan M; Dance, Jamison; Taylor, Russ J; Prince, John T

    2013-11-15

    Quality control in mass spectrometry-based proteomics remains subjective, labor-intensive and inconsistent between laboratories. We introduce Metriculator, a software designed to facilitate long-term storage of extensive performance metrics as introduced by NIST in 2010. Metriculator features a web interface that generates interactive comparison plots for contextual understanding of metric values and an automated metric generation toolkit. The comparison plots are designed for at-a-glance determination of outliers and trends in the datasets, together with relevant statistical comparisons. Easy-to-use quantitative comparisons and a framework for integration plugins will encourage a culture of quality assurance within the proteomics community. Available under the MIT license at http://github.com/princelab/metriculator.

  20. MALDI imaging mass spectrometry and analysis of endogenous peptides.

    Science.gov (United States)

    Chatterji, Bijon; Pich, Andreas

    2013-08-01

    In recent years, MALDI imaging mass spectrometry (MALDI-IMS) has developed as a promising tool to investigate the spatial distribution of biomolecules in intact tissue specimens. Ion densities of various molecules can be displayed as heat maps while preserving anatomical structures. In this short review, an overview of different biomolecules that can be analyzed by MALDI-IMS is given. Many reviews have covered imaging of lipids, small metabolites, whole proteins and enzymatically digested proteins in the past. However, little is known about imaging of endogenous peptides, for example, in the rat brain, and this will therefore be highlighted in this review. Furthermore, sample preparation of frozen or formalin-fixed, paraffin-embedded (FFPE) tissue is crucial for imaging experiments. Therefore, some aspects of sample preparation will be addressed, including washing and desalting, the choice of MALDI matrix and its deposition. Apart from mapping endogenous peptides, their reliable identification in situ still remains challenging and will be discussed as well.

  1. Biomarker discovery for kidney diseases by mass spectrometry.

    Science.gov (United States)

    Niwa, Toshimitsu

    2008-07-15

    By the development of soft ionization such as matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), mass spectrometry (MS) has become an indispensable technique to analyze proteins. The combination of protein separation and identification such as two-dimensional gel electrophoresis and MS, surface-enhanced laser desorption/ionization-MS, liquid chromatography/MS, and capillary electrophoresis/MS has been successfully applied for proteome analysis of urine and plasma to discover biomarkers of kidney diseases. Some urinary proteins and their proteolytic fragments have been identified as biomarker candidates for kidney diseases. This article reviews recent advances in the application of proteomics using MS to discover biomarkers for kidney diseases.

  2. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry.

    Science.gov (United States)

    Colizza, Kevin; Mahoney, Keira E; Yevdokimov, Alexander V; Smith, James L; Oxley, Jimmie C

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression. Graphical Abstract ᅟ.

  3. Plant Phosphoproteomics: Analysis of Plasma Membrane Transporters by Mass Spectrometry

    DEFF Research Database (Denmark)

    Ye, Juanying; Rudashevskaya, Elena; Young, Clifford

    the phosphopeptides with optimized TiO2 and IMAC enrichment methods prior to MS analysis. We further investigated the global phosphorylation profile of the whole plant plasma membrane proteins using the combination of our recently established phosphopeptide enrichment method, Calcium phosphate precipitation...... phosphorylation. Due to the low abundance of phosphoprotein, the specific enrichment prior to MS analysis is necessary. Plant proton pump (H+-ATPase) is an enzyme controls the major transport processes in the plant, such as root nutrient uptake. Moreover, this pump has been proposed to be involved in other......  Phosphorylation is a key regulatory factor in all aspects of eukaryotic biology including the regulation of plant membrane-bound transport proteins. To date, mass spectrometry (MS) has been introduced as powerful technology for study of post translational modifications (PTMs), including protein...

  4. Electrospray Ionisation Mass Spectrometry: Principles and Clinical Applications

    Science.gov (United States)

    Ho, CS; Lam, CWK; Chan, MHM; Cheung, RCK; Law, LK; Lit, LCW; Ng, KF; Suen, MWM; Tai, HL

    2003-01-01

    This mini-review provides a general understanding of electrospray ionisation mass spectrometry (ESI-MS) which has become an increasingly important technique in the clinical laboratory for structural study or quantitative measurement of metabolites in a complex biological sample. The first part of the review explains the electrospray ionisation process, design of mass spectrometers with separation capability, characteristics of the mass spectrum, and practical considerations in quantitative analysis. The second part then focuses on some clinical applications. The capability of ESI-tandem-MS in measuring bio-molecules sharing similar molecular structures makes it particularly useful in screening for inborn errors of amino acid, fatty acid, purine, pyrimidine metabolism and diagnosis of galactosaemia and peroxisomal disorders. Electrospray ionisation is also efficient in generating cluster ions for structural elucidation of macromolecules. This has fostered a new and improved approach (vs electrophoresis) for identification and quantification of haemoglobin variants. With the understanding of glycohaemoglobin structure, an IFCC reference method for glycohaemoglobin assay has been established using ESI-MS. It represents a significant advancement for the standardisation of HbA1c in diabetic monitoring. With its other applications such as in therapeutic drug monitoring, ESI-MS will continue to exert an important influence in the future development and organisation of the clinical laboratory service. PMID:18568044

  5. Detection of bio-signature by microscopy and mass spectrometry

    Science.gov (United States)

    Tulej, M.; Wiesendanger, R.; Neuland, M., B.; Meyer, S.; Wurz, P.; Neubeck, A.; Ivarsson, M.; Riedo, V.; Moreno-Garcia, P.; Riedo, A.; Knopp, G.

    2017-09-01

    We demonstrate detection of micro-sized fossilized bacteria by means of microscopy and mass spectrometry. The characteristic structures of lifelike forms are visualized with a micrometre spatial resolution and mass spectrometric analyses deliver elemental and isotope composition of host and fossilized materials. Our studies show that high selectivity in isolation of fossilized material from host phase can be achieved while applying a microscope visualization (location), a laser ablation ion source with sufficiently small laser spot size and applying depth profiling method. Our investigations shows that fossilized features can be well isolated from host phase. The mass spectrometric measurements can be conducted with sufficiently high accuracy and precision yielding quantitative elemental and isotope composition of micro-sized objects. The current performance of the instrument allows the measurement of the isotope fractionation in per mill level and yield exclusively definition of the origin of the investigated species by combining optical visualization of investigated samples (morphology and texture), chemical characterization of host and embedded in the host micro-sized structure. Our isotope analyses involved bio-relevant B, C, S, and Ni isotopes which could be measured with sufficiently accuracy to conclude about the nature of the micro-sized objects.

  6. Fast atom bombardment tandem mass spectrometry of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)

    1995-02-01

    Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

  7. DNA sequencing using biotinylated dideoxynucleotides and mass spectrometry

    Science.gov (United States)

    Edwards, John R.; Itagaki, Yasuhiro; Ju, Jingyue

    2001-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) has been explored widely for DNA sequencing. The major requirement for this method is that the DNA sequencing fragments must be free from alkaline and alkaline earth salts as well as other contaminants for accurately measuring the masses of the DNA fragments. We report here the development of a novel MS DNA sequencing method that generates Sanger-sequencing fragments in one tube using biotinylated dideoxynucleotides. The DNA sequencing fragments that carry a biotin at the 3′-end are made free from salts and other components in the sequencing reaction by capture with streptavidin-coated magnetic beads. Only correctly terminated biotinylated DNA fragments are subsequently released and loaded onto a mass spectrometer to obtain accurate DNA sequencing data. Compared with gel electrophoresis-based sequencing systems, MS produces a very high resolution of DNA-sequencing fragments, fast separation on microsecond time scales, and completely eliminates the compressions associated with gel electrophoresis. The high resolution of MS allows accurate mutation and heterozygote detection. This optimized solid-phase DNA-sequencing chemistry plus future improvements in detector sensitivity for large DNA fragments in MS instrumentation will further improve MS for DNA sequencing. PMID:11691941

  8. Cloud parallel processing of tandem mass spectrometry based proteomics data.

    Science.gov (United States)

    Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus

    2012-10-05

    Data analysis in mass spectrometry based proteomics struggles to keep pace with the advances in instrumentation and the increasing rate of data acquisition. Analyzing this data involves multiple steps requiring diverse software, using different algorithms and data formats. Speed and performance of the mass spectral search engines are continuously improving, although not necessarily as needed to face the challenges of acquired big data. Improving and parallelizing the search algorithms is one possibility; data decomposition presents another, simpler strategy for introducing parallelism. We describe a general method for parallelizing identification of tandem mass spectra using data decomposition that keeps the search engine intact and wraps the parallelization around it. We introduce two algorithms for decomposing mzXML files and recomposing resulting pepXML files. This makes the approach applicable to different search engines, including those relying on sequence databases and those searching spectral libraries. We use cloud computing to deliver the computational power and scientific workflow engines to interface and automate the different processing steps. We show how to leverage these technologies to achieve faster data analysis in proteomics and present three scientific workflows for parallel database as well as spectral library search using our data decomposition programs, X!Tandem and SpectraST.

  9. Combinatorial Labeling Method for Improving Peptide Fragmentation in Mass Spectrometry

    Science.gov (United States)

    Kuchibhotla, Bhanuramanand; Kola, Sankara Rao; Medicherla, Jagannadham V.; Cherukuvada, Swamy V.; Dhople, Vishnu M.; Nalam, Madhusudhana Rao

    2017-06-01

    Annotation of peptide sequence from tandem mass spectra constitutes the central step of mass spectrometry-based proteomics. Peptide mass spectra are obtained upon gas-phase fragmentation. Identification of the protein from a set of experimental peptide spectral matches is usually referred as protein inference. Occurrence and intensity of these fragment ions in the MS/MS spectra are dependent on many factors such as amino acid composition, peptide basicity, activation mode, protease, etc. Particularly, chemical derivatizations of peptides were known to alter their fragmentation. In this study, the influence of acetylation, guanidinylation, and their combination on peptide fragmentation was assessed initially on a lipase (LipA) from Bacillus subtilis followed by a bovine six protein mix digest. The dual modification resulted in improved fragment ion occurrence and intensity changes, and this resulted in the equivalent representation of b- and y-type fragment ions in an ion trap MS/MS spectrum. The improved representation has allowed us to accurately annotate the peptide sequences de novo. Dual labeling has significantly reduced the false positive protein identifications in standard bovine six peptide digest. Our study suggests that the combinatorial labeling of peptides is a useful method to validate protein identifications for high confidence protein inference. [Figure not available: see fulltext.

  10. Silver Coating for High-Mass-Accuracy Imaging Mass Spectrometry of Fingerprints on Nanostructured Silicon.

    Science.gov (United States)

    Guinan, Taryn M; Gustafsson, Ove J R; McPhee, Gordon; Kobus, Hilton; Voelcker, Nicolas H

    2015-11-17

    Nanostructure imaging mass spectrometry (NIMS) using porous silicon (pSi) is a key technique for molecular imaging of exogenous and endogenous low molecular weight compounds from fingerprints. However, high-mass-accuracy NIMS can be difficult to achieve as time-of-flight (ToF) mass analyzers, which dominate the field, cannot sufficiently compensate for shifts in measured m/z values. Here, we show internal recalibration using a thin layer of silver (Ag) sputter-coated onto functionalized pSi substrates. NIMS peaks for several previously reported fingerprint components were selected and mass accuracy was compared to theoretical values. Mass accuracy was improved by more than an order of magnitude in several cases. This straightforward method should form part of the standard guidelines for NIMS studies for spatial characterization of small molecules.

  11. Assay for Glycosaminoglycans by Tandem Mass Spectrometry and its Applications

    Science.gov (United States)

    Tomatsu, Shunji; Shimada, Tsutomu; Mason, Robert W; Kelly, Joan; LaMarr, William A; Yasuda, Eriko; Shibata, Yuniko; Futatsumori, Hideyuki; Montaño, Adriana M; Yamaguchi, Seiji; Suzuki, Yasuyuki; Orii, Tadao

    2014-01-01

    Glycosaminoglycans (GAGs) are distributed in the whole body and play a variety of important physiological roles associated with inflammation, growth, coagulation, fibrinolysis, lipolysis, and cell-matrix biology. Accumulation of undegraded GAGs in lysosomes gives rise to a distinct clinical syndrome, mucopolysaccharidoses. Measurement of each specific GAG in a variety of specimens is urgently required to understand GAG interaction with other molecules, physiological status of patients, and prognosis and pathogenesis of the disease. We established a highly sensitive and accurate tandem mass spectrometry (LC-MS/MS) method for measurements of disaccharides derived from four specific GAGs [dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and chondroitin sulfate (CS)]. Disaccharides were produced by specific enzyme digestion of each GAG, and quantified by negative ion mode of multiple reaction monitoring. Subclasses of HS and GAGs with identical molecular weights can be separated using a Hypercarbcolumn (2.0 mm×50 mm, 5 μm) with an aectonitrile gradient in ammonium acetate (pH 11.0). We also developed a GAG assay by RapidFire with tandem mass spectrometry (RF-MS/MS). The RF system consists of an integrated solid phase extraction robot that binds and de-salts samples from assay plates and directly injects them into a MS/MS detector, reducing sample processing time to ten seconds. RF-MS/MS consequently yields much faster throughput than conventional LC-MS/MS-based methods. However, the RF system does not have a chromatographic step, and therefore, cannot distinguish GAGs that have identical molecular weights. Both methods can be applied to analysis of dried blood spots, blood, and urine specimens. In this article, we compare the assay methods for GAGs and describe their potential applications. PMID:25068074

  12. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry.

    Science.gov (United States)

    Liu, Yao-Min; Perry, Richard H

    2015-10-01

    On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.

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

    Science.gov (United States)

    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.

  14. ELISA reagent coverage evaluation by affinity purification tandem mass spectrometry.

    Science.gov (United States)

    Henry, Scott M; Sutlief, Elissa; Salas-Solano, Oscar; Valliere-Douglass, John

    2017-10-01

    Host cell proteins (HCPs) must be adequately removed from recombinant therapeutics by downstream processing to ensure patient safety, product quality, and regulatory compliance. HCP process clearance is typically monitored by enzyme-linked immunosorbent assay (ELISA) using a polyclonal reagent. Recently, mass spectrometry (MS) has been used to identify specific HCP process impurities and monitor their clearance. Despite this capability, ELISA remains the preferred analytical approach due to its simplicity and throughput. There are, however, inherent difficulties reconciling the protein-centric results of MS characterization with ELISA, or providing assurance that ELISA has acceptable coverage against all process-specific HCP impurities that could pose safety or efficacy risks. Here, we describe efficient determination of ELISA reagent coverage by proteomic analysis following affinity purification with a polyclonal anti-HCP reagent (AP-MS). The resulting HCP identifications can be compared with the actual downstream process impurities for a given process to enable a highly focused assessment of ELISA reagent suitability. We illustrate the utility of this approach by performing coverage evaluation of an anti-HCP polyclonal against both an HCP immunogen and the downstream HCP impurities identified in a therapeutic monoclonal antibody after Protein A purification. The overall goal is to strategically implement affinity-based mass spectrometry as part of a holistic framework for evaluating HCP process clearance, ELISA reagent coverage, and process clearance risks. We envision coverage analysis by AP-MS will further enable a framework for HCP impurity analysis driven by characterization of actual product-specific process impurities, complimenting analytical methods centered on consideration of the total host cell proteome.

  15. Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry.

    Science.gov (United States)

    Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro

    2017-09-01

    Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg -1 ; ICP-MS, 437ngg -1 ) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. Advanced capabilities for in situ planetary mass spectrometry

    Science.gov (United States)

    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

  17. Two-step ion-exchange chromatographic purification combined with reversed-phase chromatography to isolate C-peptide for mass spectrometric analysis.

    Science.gov (United States)

    Kabytaev, Kuanysh; Durairaj, Anita; Shin, Dmitriy; Rohlfing, Curt L; Connolly, Shawn; Little, Randie R; Stoyanov, Alexander V

    2016-02-01

    A liquid chromatography with mass spectrometry on-line platform that includes the orthogonal techniques of ion exchange and reversed phase chromatography is applied for C-peptide analysis. Additional improvement is achieved by the subsequent application of cation- and anion-exchange purification steps that allow for isolating components that have their isoelectric points in a narrow pH range before final reversed-phase mass spectrometry analysis. The utility of this approach for isolating fractions in the desired "pI window" for profiling complex mixtures is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry

    Science.gov (United States)

    Glover, Matthew S.; Dilger, Jonathan M.; Acton, Matthew D.; Arnold, Randy J.; Radivojac, Predrag; Clemmer, David E.

    2016-05-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/ trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences.

  19. Fast and Efficient XML Data Access for Next-Generation Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Hannes L Röst

    Full Text Available In mass spectrometry-based proteomics, XML formats such as mzML and mzXML provide an open and standardized way to store and exchange the raw data (spectra and chromatograms of mass spectrometric experiments. These file formats are being used by a multitude of open-source and cross-platform tools which allow the proteomics community to access algorithms in a vendor-independent fashion and perform transparent and reproducible data analysis. Recent improvements in mass spectrometry instrumentation have increased the data size produced in a single LC-MS/MS measurement and put substantial strain on open-source tools, particularly those that are not equipped to deal with XML data files that reach dozens of gigabytes in size.Here we present a fast and versatile parsing library for mass spectrometric XML formats available in C++ and Python, based on the mature OpenMS software framework. Our library implements an API for obtaining spectra and chromatograms under memory constraints using random access or sequential access functions, allowing users to process datasets that are much larger than system memory. For fast access to the raw data structures, small XML files can also be completely loaded into memory. In addition, we have improved the parsing speed of the core mzML module by over 4-fold (compared to OpenMS 1.11, making our library suitable for a wide variety of algorithms that need fast access to dozens of gigabytes of raw mass spectrometric data.Our C++ and Python implementations are available for the Linux, Mac, and Windows operating systems. All proposed modifications to the OpenMS code have been merged into the OpenMS mainline codebase and are available to the community at https://github.com/OpenMS/OpenMS.

  20. Fast and Efficient XML Data Access for Next-Generation Mass Spectrometry.

    Science.gov (United States)

    Röst, Hannes L; Schmitt, Uwe; Aebersold, Ruedi; Malmström, Lars

    2015-01-01

    In mass spectrometry-based proteomics, XML formats such as mzML and mzXML provide an open and standardized way to store and exchange the raw data (spectra and chromatograms) of mass spectrometric experiments. These file formats are being used by a multitude of open-source and cross-platform tools which allow the proteomics community to access algorithms in a vendor-independent fashion and perform transparent and reproducible data analysis. Recent improvements in mass spectrometry instrumentation have increased the data size produced in a single LC-MS/MS measurement and put substantial strain on open-source tools, particularly those that are not equipped to deal with XML data files that reach dozens of gigabytes in size. Here we present a fast and versatile parsing library for mass spectrometric XML formats available in C++ and Python, based on the mature OpenMS software framework. Our library implements an API for obtaining spectra and chromatograms under memory constraints using random access or sequential access functions, allowing users to process datasets that are much larger than system memory. For fast access to the raw data structures, small XML files can also be completely loaded into memory. In addition, we have improved the parsing speed of the core mzML module by over 4-fold (compared to OpenMS 1.11), making our library suitable for a wide variety of algorithms that need fast access to dozens of gigabytes of raw mass spectrometric data. Our C++ and Python implementations are available for the Linux, Mac, and Windows operating systems. All proposed modifications to the OpenMS code have been merged into the OpenMS mainline codebase and are available to the community at https://github.com/OpenMS/OpenMS.

  1. Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

    Science.gov (United States)

    Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

    2017-12-23

    Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Proteomics Analyses of the Opportunistic Pathogen Burkholderia vietnamiensis Using Protein Fractionations and Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Samanthi Wickramasekara

    2011-01-01

    Full Text Available The main objectives of this work were to obtain a more extensive coverage of the Burkholderia vietnamiensis proteome than previously reported and to identify virulence factors using tandem mass spectrometry. The proteome of B. vietnamiensis was precipitated into four fractions to as extracellular, intracellular, cell surface and cell wall proteins. Two different approaches were used to analyze the proteins. The first was a gel-based method where 1D SDS-PAGE was used for separation of the proteins prior to reverse phase liquid chromatography tandem mass spectrometry (LC-MS/MS. The second method used MudPIT analysis (Multi dimensional Protein Identification Technique, where proteins are digested and separated using cation exchange and reversed phase separations before the MS/MS analysis (LC/LC-MS/MS. Overall, gel-based LC-MS/MS analysis resulted in more protein identifications than the MudPIT analysis. Combination of the results lead to identification of more than 1200 proteins, approximately 16% of the proteins coded from the annotated genome of Burkholderia species. Several virulence factors were detected including flagellin, porin, peroxiredoxin and zinc proteases.

  3. Exploiting flow injection and sequential injection for trace metal determinations in conjunction with detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    Despite their excellent analytical chemical capacities, Electrothermal Atomic Absorption Spectrometry (ETAAS) and Inductively Coupled Plasma Mass Spectrometry (ICPMS), nevertheless, often require suitable pretreatment of the sample material in order to obtain the necessary sensitivity...... and selectivity. Either in order to separate/preconcentrate the analyte material, or because of the presence of potentially interfering matrix constituents. Such pretreatments are advantageously performed in flow injection (FI) or sequential injection (SI) manifolds, where all appropriate unit operations can......, such as liquid-liquid extraction, (co)precipitation with collection in knotted reactors, adsorption, hydride generation, or the use of ion-exchange columns. Apart from hydride generation, where the analyte is converted into a gaseous species, the common denominator for these approaches is that the analyte...

  4. Product analysis of caffeic acid oxidation by on-line electrochemistry/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Arakawa, Ryuichi; Yamaguchi, Masashi; Hotta, Hiroki; Osakai, Toshiyuki; Kimoto, Takashi

    2004-08-01

    On-line electrochemistry/electrospray ionization mass spectrometry (EC/ESI-MS) was developed using a microflow electrolytic cell. This technique was applied to electrochemical oxidation of caffeic acid (CAF) which is known to be a highly antioxidative agent. Effects of electrolytic potentials on ion intensities of product ions and on electrolytic currents were examined at different pHs. Dimer products were detected at electrolytic potentials of E = 0.7 V (vs. Ag/AgCl) and trimer products at 1.0 V at pH 9. Dimer products were distinguished from hydrogen-bonded complexes by MS/MS experiments. Hydrogen/deuterium exchange experiments determined the number of hydroxyl and carboxyl groups in the Dimers formed by electrolysis. The mechanism of oxidative polymerization of CAF is discussed with speculation as to the structure of the dimer product.

  5. A versatile method for stable carbon isotope analysis of carbohydrates by high-performance liquid chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Boschker, H.T.S.; Moerdijk-Poortvliet, T.C.W.; Van Breugel, P.; Houtekamer, M.J.; Middelburg, J.J.

    2008-01-01

    We have developed a method to analyze stable carbon isotope (13C/12C) ratios in a variety of carbohydrates using high-performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS). The chromatography is based on strong anion-exchange columns with low strength NaOH eluents. An eluent

  6. Preparation of Single Cells for Imaging Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Berman, E S; Fortson, S L; Kulp, K S; Checchi, K D; Wu, L; Felton, J S; Wu, K J

    2007-10-24

    Characterizing chemical changes within single cells is important for determining fundamental mechanisms of biological processes that will lead to new biological insights and improved disease understanding. Imaging biological systems with mass spectrometry (MS) has gained popularity in recent years as a method for creating precise chemical maps of biological samples. In order to obtain high-quality mass spectral images that provide relevant molecular information about individual cells, samples must be prepared so that salts and other cell-culture components are removed from the cell surface and the cell contents are rendered accessible to the desorption beam. We have designed a cellular preparation protocol for imaging MS that preserves the cellular contents for investigation and removes the majority of the interfering species from the extracellular matrix. Using this method, we obtain excellent imaging results and reproducibility in three diverse cell types: MCF7 human breast cancer cells, Madin-Darby canine kidney (MDCK) cells, and NIH/3T3 mouse fibroblasts. This preparation technique allows routine imaging MS analysis of cultured cells, allowing for any number of experiments aimed at furthering scientific understanding of molecular processes within individual cells.

  7. Mass spectrometry for the discovery of biomarkers of sepsis.

    Science.gov (United States)

    Ludwig, Katelyn R; Hummon, Amanda B

    2017-03-28

    Sepsis is a serious medical condition that occurs in 30% of patients in intensive care units (ICUs). Early detection of sepsis is key to prevent its progression to severe sepsis and septic shock, which can cause organ failure and death. Diagnostic criteria for sepsis are nonspecific and hinder a timely diagnosis in patients. Therefore, there is currently a large effort to detect biomarkers that can aid physicians in the diagnosis and prognosis of sepsis. Mass spectrometry is often the method of choice to detect metabolomic and proteomic changes that occur during sepsis progression. These "omics" strategies allow for untargeted profiling of thousands of metabolites and proteins from human biological samples obtained from septic patients. Differential expression of or modifications to these metabolites and proteins can provide a more reliable source of diagnostic biomarkers for sepsis. Here, we focus on the current knowledge of biomarkers of sepsis and discuss the various mass spectrometric technologies used in their detection. We consider studies of the metabolome and proteome and summarize information regarding potential biomarkers in both general and neonatal sepsis.

  8. Geoporphyrin analysis using electrospray ionization-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, G.J.; Quinones, M.A.; Quirke, J.M.E. (Oak Ridge National Laboratory, Oak Ridge, TN (USA). Analytical Chemistry Division)

    The utility of electrospray ionization combined with mass spectrometry (ES-MS) for the analysis of free-base, nickel and vanadyl geoporphyrins is demonstrated. In positive ion mode, free-base alkyl-substituted porphyrins are detected as the protonated molecule, (M + H)[sup +], while the nickel and vanadyl chelates of these same porphyrins are observed as their radical cations, M[sup .+], as is chlorophyll a. Detection of free-base octaethylporphyrin (OEP) using continuous infusion at 1-5 [mu]L/min required sampling as little as 1 fmol of material, while at these same flow rates 18 fmol of OEP could be detected via flow injection. Detection of 500 fmol of mesoporphyrin IX dimethyl ester injected is demonstrated using on-line reverse-phase microbore-HPLC at a solvent flow rate of 40 [mu]L/min. ES-MS is shown to be well-suited for geoporphyrin molecular weight and carbon number determination since no fragment ions are produced by this ionization process. Accuracy in determining the relative abundances of porphyrins within geoporphyrin mixtures is demonstrated using standard solutions containing known molar ratios of OEP and free-base etioporphyrin-III (etio-III) and a total free-base porphyrin mixture isolated from Gilsonite bitumen. On-line separation/mass spectrometric detection of free-base and nickel geoporphyrin mixtures using reverse-phase microbore-HPLC/ES/MS is demonstrated with Gilsonite porphyrins. 51 refs., 11 figs.

  9. Coupling of ultrafast LC with mass spectrometry by DESI.

    Science.gov (United States)

    Cai, Yi; Liu, Yong; Helmy, Roy; Chen, Hao

    2014-10-01

    Recently we reported a desorption electrospray ionization (DESI) interface to combine liquid chromatography (LC) with mass spectrometry (MS) using a new LC eluent splitting strategy through a tiny orifice on LC capillary tube [J. Am. Soc. Mass Spectrom. 25, 286 (2014)]. The interface introduces negligible dead volume and back pressure, thereby allowing "near real-time" MS detection, fast LC elution, and online MS-directed purification. This study further evaluates the LC/DESI-MS performance with focus of using ultra-fast LC. Using a monolithic C18 column, metabolites in urine can be separated within 1.6 min and can be online collected for subsequent structure elucidation (e.g., by NMR, UV, IR) in a recovery yield up to 99%. Using a spray solvent with alkaline pH, negative ions could be directly generated for acidic analytes (e.g., ibuprofen) in acidic LC eluent by DESI, offering a novel protocol to realize "wrong-way around" ionization for LC/MS analysis. In addition, DESI-MS is found to be compatible with ultra-performance liquid chromatography (UPLC) for the first time.

  10. Mass spectrometry in the characterization of reactive metal alkoxides.

    Science.gov (United States)

    Peruzzo, Valentina; Chiurato, Matteo Andrea; Favaro, Monica; Tomasin, Patrizia

    2016-04-04

    Metal alkoxides are metal-organic compounds characterized by the presence of MOC bonds (M = metal). Their chemistry seems to be, in principle, relatively simple but the number of possible reactant species arising as a consequence of their behavior is very remarkable. The physico-chemical properties of metal alkoxides are determined by many different parameters, the most important ones being the electronegativity of the metal, the ramification of the ligand, and the acidity of the corresponding alcohol. Their reactivity makes them suitable and versatile candidates for many applications, including homogeneous catalysis, synthesis of new ceramic materials through the sol-gel process and, recently, also for Cultural Heritage. Metal alkoxides are characterized by a strong tendency to give clusters and/or oligomers through oxo-bridges. Mass spectrometry has been successfully employed for the characterization of metal alkoxides in the gas-phase. Electron ionization (EI) allowed the assessment of the molecular weight and of the most relevant decomposition pathways giving information on the relative bond strength of differently substituted molecules. On the other hand, information on the reactivity in solution of these molecules have been obtained by electrospray ionization (ESI)-matrix assisted laser desorption ionization (MALDI) experiments performed on their reaction products. These data were relevant to investigate the sol-gel process. In this review, these aspects are described and the results obtained are critically evaluated. © 2016 Wiley Periodicals, Inc. Mass Spec Rev. © 2016 Wiley Periodicals, Inc.

  11. Applications of MALDI Mass Spectrometry in Clinical Chemistry.

    Science.gov (United States)

    Duncan, Mark W; Nedelkov, Dobrin; Walsh, Ryan; Hattan, Stephen J

    2016-01-01

    MALDI-TOF mass spectrometry (MS) is set to make inroads into clinical chemistry because it offers advantages over other analytical platforms. These advantages include low acquisition and operating costs, ease of use, ruggedness, and high throughput. When coupled with innovative front-end strategies and applied to important clinical problems, it can deliver rapid, sensitive, and cost-effective assays. This review describes the general principles of MALDI-TOF MS, highlights the unique features of the platform, and discusses some practical methods based upon it. There is substantial potential for MALDI-TOF MS to make further inroads into clinical chemistry because of the selectivity of mass detection and its ability to independently quantify proteoforms. MALDI-TOF MS has already transformed the practice of clinical microbiology and this review illustrates how and why it is now set to play an increasingly important role in in vitro diagnostics in particular, and clinical chemistry in general. © 2015 American Association for Clinical Chemistry.

  12. Infrared laser ablation atmospheric pressure photoionization mass spectrometry.

    Science.gov (United States)

    Vaikkinen, Anu; Shrestha, Bindesh; Kauppila, Tiina J; Vertes, Akos; Kostiainen, Risto

    2012-02-07

    In this paper we introduce laser ablation atmospheric pressure photoionization (LAAPPI), a novel atmospheric pressure ion source for mass spectrometry. In LAAPPI the analytes are ablated from water-rich solid samples or from aqueous solutions with an infrared (IR) laser running at 2.94 μm wavelength. Approximately 12 mm above the sample surface, the ablation plume is intercepted with an orthogonal hot solvent (e.g., toluene or anisole) jet, which is generated by a heated nebulizer microchip and directed toward the mass spectrometer inlet. The ablated analytes are desolvated and ionized in the gas-phase by atmospheric pressure photoionization using a 10 eV vacuum ultraviolet krypton discharge lamp. The effect of operational parameters and spray solvent on the performance of LAAPPI is studied. LAAPPI offers ~300 μm lateral resolution comparable to, e.g., matrix-assisted laser desorption ionization. In addition to polar compounds, LAAPPI efficiently ionizes neutral and nonpolar compounds. The bioanalytical application of the method is demonstrated by the direct LAAPPI analysis of rat brain tissue sections and sour orange (Citrus aurantium) leaves. © 2012 American Chemical Society

  13. Direct Detection of Biotinylated Proteins by Mass Spectrometry

    Science.gov (United States)

    2015-01-01

    Mass spectrometric strategies to identify protein subpopulations involved in specific biological functions rely on covalently tagging biotin to proteins using various chemical modification methods. The biotin tag is primarily used for enrichment of the targeted subpopulation for subsequent mass spectrometry (MS) analysis. A limitation of these strategies is that MS analysis does not easily discriminate unlabeled contaminants from the labeled protein subpopulation under study. To solve this problem, we developed a flexible method that only relies on direct MS detection of biotin-tagged proteins called “Direct Detection of Biotin-containing Tags” (DiDBiT). Compared with conventional targeted proteomic strategies, DiDBiT improves direct detection of biotinylated proteins ∼200 fold. We show that DiDBiT is applicable to several protein labeling protocols in cell culture and in vivo using cell permeable NHS-biotin and incorporation of the noncanonical amino acid, azidohomoalanine (AHA), into newly synthesized proteins, followed by click chemistry tagging with biotin. We demonstrate that DiDBiT improves the direct detection of biotin-tagged newly synthesized peptides more than 20-fold compared to conventional methods. With the increased sensitivity afforded by DiDBiT, we demonstrate the MS detection of newly synthesized proteins labeled in vivo in the rodent nervous system with unprecedented temporal resolution as short as 3 h. PMID:25117199

  14. Screening of carnitine and biotin deficiencies on tandem mass spectrometry.

    Science.gov (United States)

    Hagiwara, Shin-Ichiro; Kubota, Mitsuru; Nambu, Ryusuke; Kagimoto, Seiichi

    2017-04-01

    It is important to assess pediatric patients for nutritional deficiency when they are receiving specific interventions, such as enteral feeding. We focused on measurement of C0 and 3-hydroxyisovalerylcarnitine (C5-OH) with tandem mass spectrometry (MS/MS), which is performed as part of the newborn mass screening. The purpose of this study was to investigate the usefulness of MS/MS for screening carnitine and biotin deficiencies. Forty-two children (24 boys, 18 girls) were enrolled between December 2013 and December 2015. Blood tests, including measurement of serum free carnitine via the enzyme cycling method, and acylcarnitine analysis on MS/MS of dried blood spot (DBS), were performed for the evaluation of nutrition status. Median patient age was 2 years (range, 2 months-14 years). Mean serum free carnitine was 41.8 ± 19.2 μmol/L. In six of the 42 patients, serum free carnitine was 1.00 nmol/L. Therapy-resistant eczema was improved by treatment with additional biotin and a non-hydrolyzed formula. C0 and C5-OH, measured on MS/MS of DBS, were useful for screening carnitine and biotin deficiencies. © 2016 Japan Pediatric Society.

  15. Protein Glycation in Diabetes as Determined by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Annunziata Lapolla

    2013-01-01

    Full Text Available Diabetes is a common endocrine disorder characterized by hyperglycemia leading to nonenzymatic glycation of proteins, responsible for chronic complications. The development of mass spectrometric techniques able to give highly specific and reliable results in proteome field is of wide interest for physicians, giving them new tools to monitor the disease progression and the possible complications related to diabetes, as well as the effectiveness of therapeutic treatments. This paper reports and discusses some of the data pertaining protein glycation in diabetic subjects obtained by matrix-assisted laser desorption ionization (MALDI mass spectrometry (MS. The preliminary studies carried out by in vitro protein glycation experiments show clear differences in molecular weight of glycated and unglycated proteins. Then, the attention was focused on plasma proteins human serum albumin (HSA and immunoglobulin G (IgG. Enzymatic degradation products of in vitro glycated HSA were studied in order to simulate the in vivo enzymatic digestion of glycated species by the immunological system leading to the highly reactive advanced glycation end-products (AGEs peptides. Further studies led to the evaluation of glycated Apo A-I and glycated haemoglobin levels. A different MALDI approach was employed for the identification of markers of disease in urine samples of healthy, diabetic, nephropathic, and diabetic-nephropathic subjects.

  16. Mass Spectrometry of Synthetic Polysiloxanes: From Linear Models to Plasma Polymer Networks

    National Research Council Canada - National Science Library

    Fouquet, Thierry

    2014-01-01

    ...) for their mass analysis. Application of the fragmentation routes defined for polysiloxane standards turned the tandem mass spectrometry behavior of these newly soluble plasma oligomers into pieces of information to further...

  17. Integrative Mass Spectrometry Approaches to Monitor Protein Structures, Modifications, and Interactions

    NARCIS (Netherlands)

    Lössl, P.

    2017-01-01

    This thesis illustrates the current standing of mass spectrometry (MS) in molecular and structural biology. The primary aim of the herein described research is to facilitate protein characterization by combining mass spectrometric methods among each other and with complementary analytical

  18. Routine identification of Nocardia species by MALDI-TOF mass spectrometry

    NARCIS (Netherlands)

    Girard, V.; Mailler, S.; Polsinelli, S.; Jacob, D.; Saccomani, M.C.; Celliere, B.; Monnin, V.; Belkum, A. van; Hagen, F.; Meis, J.F.G.M.; Durand, G.

    2017-01-01

    We here show adequate species identification for bacterial isolates of the genus Nocardia spp. through VITEK mass spectrometry. Application of a specific sample preparation method in combination with a robust matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

  19. Multidimensional chromatography coupled to mass spectrometry in analysing complex proteomics samples

    NARCIS (Netherlands)

    Horvatovich, Peter; Hoekman, Berend; Govorukhina, Natalia; Bischoff, Rainer

    Multidimensional chromatography coupled to mass spectrometry (LC(n)-MS) provides more separation power and an extended measured dynamic concentration range to analyse complex proteomics samples than one dimensional liquid chromatography coupled to mass spectrometry (1D-LC-MS). This review gives an

  20. Analysis of Chaperone Complexes by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    NARCIS (Netherlands)

    Geels, R.B.J.

    2008-01-01

    Investigation of methodologies for analyses of noncovalently bound protein assemblies using Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR-MS) and quadrupole Time-of-Flight (qToF) mass spectrometry. Specifically, the co-chaperonins GroEL and gp31 are used to perform

  1. On-line microseparations with Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Hofstadler, S.A.; Zhao, Zhongxi; Gale, D.C.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States)

    1994-12-31

    The combination of capillary electrophoresis (CE) with electrospray ionization mass spectrometry (ESI/MS) is a powerful bioanalytical tool. Accurate charge states are readily obtained through high resolution MS techniques such as Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. In this study, the authors examine the practical considerations that were necessary for successful on-line CE-ESI/FTICR MS.

  2. Test Sample for the Spatially Resolved Quantification of Illicit Drugs on Fingerprints Using Imaging Mass Spectrometry

    NARCIS (Netherlands)

    Muramoto, S.; Forbes, T.P.; van Asten, A.C.; Gillen, G.

    2015-01-01

    A novel test sample for the spatially resolved quantification of illicit drugs on the surface of a fingerprint using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and desorption electrospray ionization mass spectrometry (DESI-MS) was demonstrated. Calibration curves relating the signal

  3. Following the Biochemical and Morphological Changes of Bacillus atrophaeus during Sporulation using Bioaerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, H J; Pitesky, M E; Fergenson, D P; Horn, J; Frank, M; Gard, E E

    2006-05-03

    The overall objective of this report is to develop a real-time single-particle mass spectrometry technique called Bio-Aerosol Mass Spectrometry (BAMS) in order to efficiently screen and identify bioaerosols and single cells of national security and public health concern.

  4. Low-Temperature Positive Secondary Ion Mass Spectrometry of Neat and Argon-Diluted Organic Solids

    NARCIS (Netherlands)

    Jonkman, Harry T.; Michl, Josef; King, Robert N.; Andrade, Joseph D.

    1978-01-01

    Secondary ion mass spectrometry of neat solid propane, n-pentane, benzene, toluene, and of propane imbedded in an argon matrix were observed at temperatures varying from 10 to 110 K and show fragmentation patterns similar to those known from ordinary electron impact mass spectrometry. The effects of

  5. Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, Vincenzo

    2016-01-01

    The use of liquid chromatography high-resolution mass spectrometry (LC-HRMS) and direct analysis real-time high-resolution mass spectrometry (DART-HRMS) defines a new scenario in the analysis of thermal-induced toxicants, such as acrylamide. Several factors contribute to the definition of the

  6. Simulation of Two Dimensional Electrophoresis and Tandem Mass Spectrometry for Teaching Proteomics

    Science.gov (United States)

    Fisher, Amanda; Sekera, Emily; Payne, Jill; Craig, Paul

    2012-01-01

    In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations--2D electrophoresis and tandem mass spectrometry.…

  7. Variability in Mass Spectrometry-based Quantification of Clinically Relevant Drug Transporters and Drug Metabolizing Enzymes

    NARCIS (Netherlands)

    Wegler, C.; Gaugaz, F.Z.; Andersson, T.B.; Wiśniewski, J.R.; Busch, D.; Gröer, C.; Oswald, S.; Norén, A.; Weiss, F.; Hammer, H.S.; Joos, T.O.; Poetz, O.; Achour, B.; Rostami-Hodjegan, A.; Steeg, E. van de; Wortelboer, H.M.; Artursson, P.

    2017-01-01

    Many different methods are used for mass-spectrometry-based protein quantification in pharmacokinetics and systems pharmacology. It has not been established to what extent the results from these various methods are comparable. Here, we compared six different mass spectrometry-based proteomics

  8. Quantitation of mycotoxins using direct analysis in real time (DART)-mass spectrometry (MS)

    Science.gov (United States)

    Ambient ionization represents a new generation of mass spectrometry ion sources which is used for rapid ionization of small molecules under ambient conditions. The combination of ambient ionization and mass spectrometry allows analyzing multiple food samples with simple or no sample treatment, or in...

  9. STRUCTURAL CHARACTERIZATION OF THE DECOMPOSITION PRODUCTS OF SALBUTAMOL BY LIQUID-CHROMATOGRAPHY IONSPRAY MASS-SPECTROMETRY

    NARCIS (Netherlands)

    MALKKILAINE, L; BRUINS, AP

    Liquid chromatography-ionspray mass spectrometry was used to elucidate the structures of the decomposition products of salbutamol. The best sensitivity in mass spectrometry was achieved by using a mixture of acetonitrile and ammonium formate (10 mM, pH 3.3) as the mobile phase in liquid

  10. Advanced mass calibration and visualization for FT-ICR mass spectrometry imaging.

    Science.gov (United States)

    Smith, Donald F; Kharchenko, Andriy; Konijnenburg, Marco; Klinkert, Ivo; Paša-Tolić, Ljiljana; Heeren, Ron M A

    2012-11-01

    Mass spectrometry imaging by Fourier transform ion cyclotron resonance (FT-ICR) yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for FT-ICR MS imaging were investigated. Sub-parts-per-million mass accuracy is demonstrated over an entire tissue section. Ion abundance fluctuations are corrected by addition of total and relative ion abundances for a root-mean-square error of 0.158 ppm on 16,764 peaks. A new approach for visualization of FT-ICR MS imaging data at high resolution is presented. The "Mosaic Datacube" provides a flexible means to visualize the entire mass range at a mass spectral bin width of 0.001 Da. The high resolution Mosaic Datacube resolves spectral features not visible at lower bin widths, while retaining the high mass accuracy from the calibration methods discussed.

  11. Plasma Desorption Mass Spectrometry analysis of HCOOH ice

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, D.P.P.; Rocco, M.L.M. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21949-900 Rio de Janeiro, RJ (Brazil); Boechat-Roberty, H.M. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Centro, Rio de Janeiro, RJ (Brazil); Iza, P.; Martinez, R. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil); Homem, M.G.P. [Laboratorio Nacional de Luz Sincrotron (LNLS), Box 6192, 13084-971 Campinas, SP (Brazil); Silveira, E.F. da [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil)], E-mail: enio@vdg.fis.puc-rio.br

    2007-03-15

    Planetary magnetospheres, in which outer planet satellites orbit, are bombarded by energetic particles inducing chemical and physical changes in their icy surfaces. The existing condensed gases react to form new products, which then undergo thermal evolution from the natural day/night cycles of these satellites. Plasma irradiation of ice causes phase changes, e.g., water ice from crystalline to amorphous over short timescales. When ice is recrystallized by heating, the surface layers retain some disorder, which promote reactions among adsorbed molecules such as H{sub 2}O, CO{sub 2}, CH{sub 2}CO, HCOOH and theirs radiolysis products. In this work, chemical reactions involving formic acid condensed at 56 K are analyzed by using Plasma Desorption Mass Spectrometry-time-of-flight ({sup 252}Cf-PDMS-TOF). Mass spectra of positive and negative desorbed ions were obtained, giving information on the structure and abundance of the molecules on the ice; the expected cations and anions generated by the HCOOH dissociation have been observed. Furthermore, several series of cluster ions were also detected, all exhibiting the structure X{sub n}Y{sub m}R{sup {+-}}, where X and Y are the neutral ice molecules, such as HCOOH or H{sub 2}O, and R{sup {+-}} is either an atomic or a molecular ion, such as H{sup +}, H{sub 3}O{sup +} or COOH{sup -}. In general, the desorption yields of the observed positive and negative ions are characterized by a decreasing exponential function as the emitted ion mass increases; however, the (HCOOH){sub n}OH{sup -} series presents its maximum at n = 8.

  12. U-series dating using thermal ionisation mass spectrometry (TIMS)

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, M.T. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science

    1999-11-01

    U-series dating is based on the decay of the two long-lived isotopes{sup 238}U({tau}{sub 1/2}=4.47 x 10{sup 9} years) and {sup 235}U ({tau}{sub 1/2} 0.7 x 10{sup 9} years). {sup 238}U and its intermediate daughter isotopes {sup 234}U ({tau}{sub 1/2} = 245.4 ka) and {sup 230}Th ({tau}{sub 1/2} = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay {sup 235}U to {sup 231}Pa ({tau}{sub 1/2} = 32.8 ka). Both the {sup 238}U and {sup 235}U decay chains terminate at the stable isotopes {sup 206}Pb and {sup 207}Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980`s when Chen et al., (1986) made the first precise measurements of {sup 234}U and {sup 232}Th in seawater followed by Edwards et al., (1987) who made combined {sup 234}U-{sup 230}Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series 9 refs., 3 figs.

  13. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

    Energy Technology Data Exchange (ETDEWEB)

    Luong, Elise [Iowa State Univ., Ames, IA (United States)

    1999-05-10

    This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 ± 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-trace concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 ± 0.4 ng/g, while the certified value is 11.5 ± 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 ± 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and β-cyclodextrin are chosen for the study, initial observation of spectral interference of 13C+ with 12C 1H+ comes from the incomplete dissociation of myoglobin and/or β-cyclodextrin.

  14. Quantify this! Report on a round table discussion on quantitative mass spectrometry in proteomics.

    Science.gov (United States)

    Quadroni, Manfredo; Ducret, Axel; Stöcklin, Reto

    2004-08-01

    quality of the results was not particularly dependant on the strategy used, as all approaches allowed Lication of identification of a certain number of protein families. The genus of the snake was identified in most cases, but the species was ambiguous. Surprisingly, the precise identification of the recombinant almost pure polypeptides appeared to be much more complicated than expected as only one group reported the full sequence. Finally the SPS'03 meeting reported here included a round table on the difficult and challenging task of "Quantification by Mass Spectrometry", a discussion sustained by four selected oral presentations on the use of stable isotopes, electrospray ionization versus matrix-assisted laser desorption/ionization approaches to quantify peptides and proteins in biological fluids, the handling of differential two-dimensional liquid chromatography tandem mass spectrometry data resulting from high throughput experiments, and the quantitative analysis of PTMs. During these three events at the SPS meetings, the impressive quality and quantity of exchanges between the developers and providers of mass spectrometry equipment and software, expert users and the audience, were a key element for the success of these fruitful events and will have definitively paved the way for future round tables and challenging exercises at SPS meetings.

  15. Investigation of the ozonation products of natural complex mixtures using Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Kostyukevich, Yury; Stavitskaya, Anna; Zherebker, Alexander; Konstantinova, Marina; Vlaskin, Mikhail; Borisova, Ludmila; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2017-08-01

    Natural complex mixtures such as oil and dissolved organic matter play an important role in the economy and in the global carbon cycle. One of the most promising approaches for the investigation of the chemical structure of such substances is the combination of the high-resolution mass spectrometry and selective chemical reactions. Here, we report the investigation of the ozonation products of natural complex mixtures using Fourier transform ion cyclotron resonance mass spectrometry. Ozonation of crude oil results in the appearance of the new compounds with high content (up to 9 atom) of oxygen. Isotopic exchange reaction showed that those oxygen stem from the carbonyl groups. Ozonation of the dissolved organic matter leads to the destruction of the substance and shift towards the region of the saturated compounds.

  16. Large-scale analysis of in Vivo phosphorylated membrane proteins by immobilized metal ion affinity chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Nühse, Thomas S; Stensballe, Allan; Jensen, Ole N

    2003-01-01

    Global analyses of protein phosphorylation require specific enrichment methods because of the typically low abundance of phosphoproteins. To date, immobilized metal ion affinity chromatography (IMAC) for phosphopeptides has shown great promise for large-scale studies, but has a reputation for poor...... specificity. We investigated the potential of IMAC in combination with capillary liquid chromatography coupled to tandem mass spectrometry for the identification of plasma membrane phosphoproteins of Arabidopsis. Without chemical modification of peptides, over 75% pure phosphopeptides were isolated from...... plasma membrane digests and detected and sequenced by mass spectrometry. We present a scheme for two-dimensional peptide separation using strong anion exchange chromatography prior to IMAC that both decreases the complexity of IMAC-purified phosphopeptides and yields a far greater coverage...

  17. Fluconazole bioequivalence study: quantification by tandem mass spectrometry.

    Science.gov (United States)

    Moraes, L A; Lerner, F E; Moraes, M E; Moraes, M O; Corso, G; De Nucci, G

    1999-04-01

    To develop a new method for quantifying fluoconazole in human plasma and to compare the bioavailability of two fluconazole capsule formulations, an open, randomized, two-period crossover study with a one-week washout interval was conducted in 24 healthy volunteers. Plasma samples were obtained up to 168 hours after drug administration and the serum fluconazole concentrations were analyzed using electrospray tandem mass spectrometry coupled to liquid chromatography using multiple reaction monitoring mode. The pharmacokinetic parameters obtained for fluconazole after the administration of each formulation included the Area under the curve (AUC)(0-168h), AUC(0-infinity), Cmax, Cmax/AUC(0-168h), Tmax, elimination rate constant (Ke), and half-life (T1/2). Within- and between-run imprecision was less than 2.3% and 8.2%, respectively. Inaccuracy within and between runs was -1.5% and -9.7%, respectively. The pharmacokinetic parameters for bioequivalence showed a normal distribution, and the variance of AUC(0-168h), AUC(0-infinity), and Cmax were homoscedastic. The geometric mean for the Fluconal/Zoltec (Fluconal; Libbs Farmacêutica Ltda, São Paulo, Brazil; Zoltec; Laboratórios Pfizer Ltda., São Paulo, Brazil) individual percent ratio was 94.9% for AUC(0-168h), 94.7% for AUC(0-infinity), 80.1% for Cmax, 102.6% for Ke, 97.5% for T1/2, and 0.93 for Tmax (arithmetic mean of individual differences). We have developed a method in which liquid chromatography is coupled with electrospray tandem mass spectrometry to improve the pharmacokinetic analysis of fluconazole. Because the 90% CI AUC is within the interval proposed for the Food and Drug Administration, we concluded that Fluconal is bioequivalent to Zoltec in terms of absorption. The CV was 27.5% for the Cmax parameter, indicating that fluconazole's absorption rate is highly variable. The European Union Regulatory Agency accepts an interval of 70-143%, and because the 90% CI for Cmax is within the interval proposed for

  18. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    J. E. Delmore

    2010-09-01

    Funding was received from NA-22 to investigate transitioning iodine isotopic analyses to an accelerator mass spectrometry (AMS) system. The present method uses gas-phase chemistry followed by thermal ionization mass spectrometry (TIMS). It was anticipated that the AMS approach could provide comparable data, with improved background levels and superior sample throughput. An aqueous extraction method was developed for removal of iodine species from high-volume air filters. Ethanol and sodium hydroxide, plus heating and ultrasonic treatment, were used to successfully extract iodine from loaded high-volume air filters. Portions of the same filters were also processed in the traditional method and analyzed by TIMS for comparison. Aliquot parts of the aqueous extracts were analyzed by AMS at the Swiss Federal Institute of Technology. Idaho National Laboratory (INL) personnel visited several AMS laboratories in the US, Spain, and Switzerland. Experience with AMS systems from several manufacturers was gained, and relationships were developed with key personnel at the laboratories. Three batches of samples were analyzed in Switzerland, and one in Spain. Results show that the INL extraction method successfully extracted enough iodine from high-volume air filters to allow AMS analysis. Comparison of the AMS and TIMS data is very encouraging; while the TIMS showed about forty percent more atoms of 129I, the 129/127 ratios tracked each other very well between the two methods. The time required for analysis is greatly reduced for the aqueous extraction/AMS approach. For a hypothetical batch of thirty samples, the AMS methodology is about five 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 for TIMS. This results from the fundamental mechanisms of ionization in the AMS system and cleanup of molecular interferences. We showed that an aqueous extraction of high

  19. Ion source memory in {sup 36}Cl accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pavetich, Stefan; Akhmadaliev, Shavkat; Merchel, Silke; Rugel, Georg [HZDR, Dresden (Germany); Arnold, Maurice; Aumaitre, Georges; Bourles, Didier; Martschini, Martin [ASTER, Aix-en-Provence (France); Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Steier, Peter [VERA, Vienna (Austria)

    2013-07-01

    Since the DREAMS (Dresden Accelerator Mass Spectrometry) facility went operational in 2011, constant effort was put into enabling routine measurements of long-lived radionuclides as {sup 10}Be, {sup 26}Al and {sup 41}Ca. For precise AMS-measurements of the volatile element Cl the key issue is the minimization of the long term memory effect. For this purpose one of the two original HVE sources was mechanically modified, allowing the usage of bigger cathodes with individual target apertures. Additionally a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, a small inter-laboratory comparison had been initiated. The long-term memory effect in the Cs sputter ion sources of the AMS facilities VERA, ASTER and DREAMS had been investigated by running samples of natural {sup 35}Cl/{sup 37}Cl-ratio and samples containing highly enriched {sup 35}Cl({sup 35}Cl/{sup 37}Cl > 500). Primary goals of the research are the time constants of the recovery from the contaminated sample ratio to the initial ratio of the sample and the level of the long-term memory effect in the sources.

  20. Integrated liquid chromatography-heated nebulizer microchip for mass spectrometry.

    Science.gov (United States)

    Haapala, Markus; Saarela, Ville; Pól, Jaroslav; Kolari, Kai; Kotiaho, Tapio; Franssila, Sami; Kostiainen, Risto

    2010-03-10

    A new integrated microchip for liquid chromatography-mass spectrometry (LC-MS) is presented. The chip is made from bonded silicon and glass wafers with structures for a packed LC column channel, a micropillar frit, a channel for optional optical detection, and a heated vaporizer section etched in silicon and platinum heater elements on the glass cover. LC eluent is vaporized and mixed with nebulizer gas in the vaporizer section and the vapor is sprayed out from the chip. Nonpolar and polar analytes can be efficiently ionized in the gas phase by atmospheric pressure photoionization (APPI) as demonstrated with polycyclic aromatic hydrocarbons (PAHs) and selective androgen receptor modulators (SARMs). This is not achievable with present LC-MS chips, since they are based on electrospray ionization, which is not able to ionize nonpolar compounds efficiently. The preliminary quantitative performance of the new chip was evaluated in terms of limit of detection (down to 5 ng mL(-1)), linearity (r>0.999), and repeatability of signal response (RSD=2.6-4.0%) and retention time (RSD=0.3-0.5%) using APPI for ionization and PAHs as standard compounds. Determination of fluorescent compounds is demonstrated by using laser-induced fluorescence (LIF) for detection in the optical detection channel before the vaporizer section. 2010 Elsevier B.V. All rights reserved.

  1. Matrix Effects in Biological Mass Spectrometry Imaging: Identification and Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Stevens, Susan; Stenzel-Poore, Mary; Laskin, Julia

    2014-07-21

    Matrix effects in mass spectrometry imaging (MSI) may affect the observed molecular distribution in chemical and biological systems. In this study, we introduce an experimental approach that efficiently compensates for matrix effects in nanospray desorption electrospray ionization (nano-DESI) MSI without introducing any complexity into the experimental protocol. We demonstrate compensation for matrix effects in nano-DESI MSI of phosphatidylcholine (PC) in normal and ischemic mouse brain tissue by doping the nano-DESI solvent with PC standards. Specifically, we use mouse brain tissue of a middle cerebral artery occlusion (MCAO) stroke model with an ischemic region localized to one hemisphere of the brain. Due to similar suppression in ionization of endogenous PC molecules extracted from the tissue and PC standards added to the solvent, matrix effects are eliminated by normalizing the intensity of the sodium and potassium adducts of endogenous PC to the intensity of the corresponding adduct of the PC standard. This approach efficiently compensates for signal variations resulting from differences in the local concentrations of sodium and potassium in tissue sections and from the complexity of the extracted analyte mixture derived from local variations in molecular composition.

  2. Uranium quantification in semen by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Todorov, Todor I; Ejnik, John W; Guandalini, Gustavo; Xu, Hanna; Hoover, Dennis; Anderson, Larry; Squibb, Katherine; McDiarmid, Melissa A; Centeno, Jose A

    2013-01-01

    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4-7% RSD and spike recoveries were 97-100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n=10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans' semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments. Published by Elsevier GmbH.

  3. Serum Biomarker Identification by Mass Spectrometry in Acute Aortic Dissection

    Directory of Open Access Journals (Sweden)

    Yong Ren

    2017-12-01

    Full Text Available Background/Aims: Aortic dissection (AD is also known as intramural hematoma. This study aimed to screen peripheral blood biomarkers of small molecule metabolites for AD using high-performance liquid chromatography-mass spectrometry (HPLC-MS. Methods: Sera from 25 healthy subjects, 25 patients with well-established AD, and 25 patients with well-established hypertension were investigated by HPLC-MS to detect metabolites, screen differentially expressed metabolites, and analyze metabolic pathways. Results: Twenty-six and four metabolites were significantly up- and down-regulated in the hypertensive patients compared with the healthy subjects; 165 metabolites were significantly up-regulated and 109 significantly down-regulated in the AD patients compared with the hypertensive patients. Of these metabolites, 35 were up-regulated and 105 down-regulated only in AD patients. The metabolites that were differentially expressed in AD are mainly involved in tryptophan, histidine, glycerophospholipid, ether lipid, and choline metabolic pathways. As AD alters the peripheral blood metabolome, analysis of peripheral blood metabolites can be used in auxiliary diagnosis of AD. Conclusion: Eight metabolites are potential biomarkers for AD, 3 of which were differentially expressed and can be used for auxiliary diagnosis of AD and evaluation of treatment effectiveness.

  4. Electrochemistry combined on-line with electrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, F.; Berkel, G.J.V. [Oak Ridge National Lab., TN (United States)

    1995-10-15

    In this paper a variety of methods to couple electrochemistry on-line with electrospray mass spectrometry (EC/ES-MS) are presented, and the fundamental and analytical utility of this hybrid technique is illustrated. The major problems encountered in coupling EC and ES-MS are discussed, and means to overcome them are presented. Three types of electrochemical flow cells, viz., a thin-layer electrode flow-by cell, a tubular electrode flow-through cell, and a porous electrode flow-through cell, are discussed in regard to their suitability for this coupling. Methods for coupling each of these electrochemical cells on-line with ES-MS, either floated at or decoupled from the ES high voltage and controlled by a constant current supply, a constant potential supply, or a potentiostat are presented. Three applications are used to illustrate the utility and versatility of the EC/ES-MS combination: (1) the ionization of neutral analytes (i.e., perylene) for detection by ES-MS, (2) the study of the products of electrode reactions (i.e., nickel(II) octaethylporphyrin oxidation products), including relatively short-lived products (i.e., {Beta}-carotene oxidation products), and (3) the enhanced determination of metals (i.e., elemental silver) achieved by coupling anodic stripping voltammetry on-line with ES-MS. 52 refs., 6 figs.

  5. COPD Exacerbation Biomarkers Validated Using Multiple Reaction Monitoring Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Janice M Leung

    Full Text Available Acute exacerbations of chronic obstructive pulmonary disease (AECOPD result in considerable morbidity and mortality. However, there are no objective biomarkers to diagnose AECOPD.We used multiple reaction monitoring mass spectrometry to quantify 129 distinct proteins in plasma samples from patients with COPD. This analytical approach was first performed in a biomarker cohort of patients hospitalized with AECOPD (Cohort A, n = 72. Proteins differentially expressed between AECOPD and convalescent states were chosen using a false discovery rate 1.2. Protein selection and classifier building were performed using an elastic net logistic regression model. The performance of the biomarker panel was then tested in two independent AECOPD cohorts (Cohort B, n = 37, and Cohort C, n = 109 using leave-pair-out cross-validation methods.Five proteins were identified distinguishing AECOPD and convalescent states in Cohort A. Biomarker scores derived from this model were significantly higher during AECOPD than in the convalescent state in the discovery cohort (p<0.001. The receiver operating characteristic cross-validation area under the curve (CV-AUC statistic was 0.73 in Cohort A, while in the replication cohorts the CV-AUC was 0.77 for Cohort B and 0.79 for Cohort C.A panel of five biomarkers shows promise in distinguishing AECOPD from convalescence and may provide the basis for a clinical blood test to diagnose AECOPD. Further validation in larger cohorts is necessary for future clinical translation.

  6. Improving Tritium Exposure Reconstructions Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Love, A; Hunt, J; Knezovich, J

    2003-06-01

    Exposure reconstructions for radionuclides are inherently difficult. As a result, most reconstructions are based primarily on mathematical models of environmental fate and transport. These models can have large uncertainties, as important site-specific information is unknown, missing, or crudely estimated. Alternatively, surrogate environmental measurements of exposure can be used for site-specific reconstructions. In cases where environmental transport processes are complex, well-chosen environmental surrogates can have smaller exposure uncertainty than mathematical models. Because existing methodologies have significant limitations, the development or improvement of methodologies for reconstructing exposure from environmental measurements would provide important additional tools in assessing the health effects of chronic exposure. As an example, the direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples, which permit greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Tritium AMS was previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases.

  7. Solvent jet desorption capillary photoionization-mass spectrometry.

    Science.gov (United States)

    Haapala, Markus; Teppo, Jaakko; Ollikainen, Elisa; Kiiski, Iiro; Vaikkinen, Anu; Kauppila, Tiina J; Kostiainen, Risto

    2015-03-17

    A new ambient mass spectrometry method, solvent jet desorption capillary photoionization (DCPI), is described. The method uses a solvent jet generated by a coaxial nebulizer operated at ambient conditions with nitrogen as nebulizer gas. The solvent jet is directed onto a sample surface, from which analytes are extracted into the solvent and ejected from the surface in secondary droplets formed in collisions between the jet and the sample surface. The secondary droplets are directed into the heated capillary photoionization (CPI) device, where the droplets are vaporized and the gaseous analytes are ionized by 10 eV photons generated by a vacuum ultraviolet (VUV) krypton discharge lamp. As the CPI device is directly connected to the extended capillary inlet of the MS, high ion transfer efficiency to the vacuum of MS is achieved. The solvent jet DCPI provides several advantages: high sensitivity for nonpolar and polar compounds with limit of detection down to low fmol levels, capability of analyzing small and large molecules, and good spatial resolution (250 μm). Two ionization mechanisms are involved in DCPI: atmospheric pressure photoionization, capable of ionizing polar and nonpolar compounds, and solvent assisted inlet ionization capable of ionizing larger molecules like peptides. The feasibility of DCPI was successfully tested in the analysis of polar and nonpolar compounds in sage leaves and chili pepper.

  8. Computing fragmentation trees from metabolite multiple mass spectrometry data.

    Science.gov (United States)

    Scheubert, Kerstin; Hufsky, Franziska; Rasche, Florian; Böcker, Sebastian

    2011-11-01

    Since metabolites cannot be predicted from the genome sequence, high-throughput de novo identification of small molecules is highly sought. Mass spectrometry (MS) in combination with a fragmentation technique is commonly used for this task. Unfortunately, automated analysis of such data is in its infancy. Recently, fragmentation trees have been proposed as an analysis tool for such data. Additional fragmentation steps (MS(n)) reveal more information about the molecule. We propose to use MS(n) data for the computation of fragmentation trees, and present the Colorful Subtree Closure problem to formalize this task: There, we search for a colorful subtree inside a vertex-colored graph, such that the weight of the transitive closure of the subtree is maximal. We give several negative results regarding the tractability and approximability of this and related problems. We then present an exact dynamic programming algorithm, which is parameterized by the number of colors in the graph and is swift in practice. Evaluation of our method on a dataset of 45 reference compounds showed that the quality of constructed fragmentation trees is improved by using MS(n) instead of MS² measurements.

  9. Laser desorption mass spectrometry for fast DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.H.; Ch`ang, L.Y.; Taranenko, N.I.; Allman, S.L.; Tang, K.; Matteson, K.J.

    1995-09-01

    During the past few years, major effort has been directed toward developing mass spectrometry to measure biopolymers because of the great potential benefit to biomedical research. Hellenkamp and his co-workers were the first to report that large polypeptide molecules can be ionized and detected without significant fragmentation when a greater number of nicotinic acid molecules are used as a matrix. This method is now well known as matrix-assisted laser desorption/ionization (MALDI). Since then, various groups have reported measurements of very large proteins by MALDI. Reliable protein analysis by MALDI is more or less well established. However, the application of MALDI to nucleic acids analysis has been found to be much more difficult. Most research on the measurement of nucleic acid by MALDI were stimulated by the Human Genome Project. Up to now, the only method for reliable routine analysis of nucleic acid is gel electrophoresis. Different sizes of nucleic acids can be separated in gel medium when a high electric field is applied to the gel. However, the time needed to separate different sizes of DNA segments usually takes from several minutes to several hours. If MALDI can be successfully used for nucleic acids analysis, the analysis time can be reduced to less than I millisecond. In addition, no tagging with radioactive materials or chemical dyes is needed. In this work, we will review recent progress related to MALDI for DNA analysis.

  10. Laser mass spectrometry for DNA fingerprinting for forensic applications

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    The application of DNA fingerprinting has become very broad in forensic analysis, patient identification, diagnostic medicine, and wildlife poaching, since every individual`s DNA structure is identical within all tissues of their body. DNA fingerprinting was initiated by the use of restriction fragment length polymorphisms (RFLP). In 1987, Nakamura et al. found that a variable number of tandem repeats (VNTR) often occurred in the alleles. The probability of different individuals having the same number of tandem repeats in several different alleles is very low. Thus, the identification of VNTR from genomic DNA became a very reliable method for identification of individuals. DNA fingerprinting is a reliable tool for forensic analysis. In DNA fingerprinting, knowledge of the sequence of tandem repeats and restriction endonuclease sites can provide the basis for identification. The major steps for conventional DNA fingerprinting include (1) specimen processing (2) amplification of selected DNA segments by PCR, and (3) gel electrophoresis to do the final DNA analysis. In this work we propose to use laser desorption mass spectrometry for fast DNA fingerprinting. The process and advantages are discussed.

  11. Mass spectrometry in clinical chemistry: the case of newborn screening.

    Science.gov (United States)

    la Marca, Giancarlo

    2014-12-01

    Newborn screening (NBS) program is a complex and organized system consisting of family and personnel education, biochemical tests, confirmatory biochemical and genetic tests, diagnosis, therapy, and patient follow up. The program identifies treatable metabolic disorders possibly when asymptomatic by using dried blood spot (DBS). During the last 20 years tandem mass spectrometry (TMS) has become the leading technology in NBS programs demonstrating to be versatile, sensitive and specific. There is consistent evidence of benefits from NBS for many disorders detected by TMS as well as for congenital hypothyroidism, cystic fibrosis, congenital adrenal hyperplasia by immune-enzymatic methods. Real time PCR tests have more recently been proposed for the detection of some severe combined immunodeficiences (SCID) along with the use of TMS for ADA and PNP SCID; a first evaluation of their cost-benefit ratio is still ongoing. Avoiding false negative results by using specific biomarkers and reducing the false positive rate by using second tier tests, is fundamental for a successful NBS program. The fully integration of NBS and diagnostic laboratories with clinical service is crucial to have the best effectiveness in a comprehensive NBS system. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Improving tritium exposure reconstructions using accelerator mass spectrometry

    Science.gov (United States)

    Hunt, J. R.; Vogel, J. S.; Knezovich, J. P.

    2010-01-01

    Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limitations, the development of tritium AMS has allowed improvements in reconstructing tritium exposure concentrations from environmental measurements and provides an important additional tool in assessing the temporal and spatial distribution of chronic exposure. Tritium exposure reconstructions using AMS were previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases. Although the current quantification limit of tritium AMS is not adequate to determine natural environmental variations in tritium concentrations, it is expected to be sufficient for studies assessing possible health effects from chronic environmental tritium exposure. PMID:14735274

  13. 'Moringa oleifera: study of phenolics and glucosinolates by mass spectrometry'.

    Science.gov (United States)

    Maldini, Mariateresa; Maksoud, Salwa A; Natella, Fausta; Montoro, Paola; Petretto, Giacomo Luigi; Foddai, Marzia; De Nicola, Gina Rosalinda; Chessa, Mario; Pintore, Giorgio

    2014-09-01

    Moringa oleifera is a medicinal plant and an excellent dietary source of micronutrients (vitamins and minerals) and health-promoting phytochemicals (phenolic compounds, glucosinolates and isothiocyanates). Glucosinolates and isothiocyanates are known to possess anti-carcinogenic and antioxidant effects and have attracted great interest from both toxicological and pharmacological points of view, as they are able to induce phase 2 detoxification enzymes and to inhibit phase 1 activation enzymes. Phenolic compounds possess antioxidant properties and may exert a preventative effect in regards to the development of chronic degenerative diseases. The aim of this work was to assess the profile and the level of bioactive compounds in all parts of M. oleifera seedlings, by using different MS approaches. First, flow injection electrospray ionization mass spectrometry (FI-ESI-MS) fingerprinting techniques and chemometrics (PCA) were used to achieve the characterization of the different plant's organs in terms of profile of phenolic compounds and glucosinolates. Second, LC-MS and LC-MS/MS qualitative and quantitative methods were used for the identification and/or determination of phenolics and glucosinolates in M. oleifera. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Microstructure synthesis control of biological polyhydroxyalkanoates with mass spectrometry

    Science.gov (United States)

    Pederson, Erik Norman

    Polyhydroxyalkanoates (PHA's) are a class of biologically produced polymers, or plastic, that is synthesized by various microorganisms. PHA's are made from biorenewable resources and are fully biodegradable and biocompatible, making them an environmentally friendly green polymer. A method of incorporating polymer microstructure into the PHA synthesized in Ralstonia eutropha was developed. These microstructures were synthesized with polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) as the polymer domains. To synthesize the PHB V copolymer, the additional presence of valerate was required. To control valerate substrate additions to the bioreactor, an off-gas mass spectrometry (MS) feedback control system was developed. Important process information including the cell physiology, growth kinetics, and product formation kinetics in the bioreactor was obtained with MS and used to control microstructure synthesis. The two polymer microstructures synthesized were core-shell granules and block copolymers. Block copolymers control the structure of the individual polymer chains while core-shell granules control the organization of many polymer chains. Both these microstructures result in properties unattainable by blending the two polymers together. The core-shell structures were synthesized with controlled domain thickness based on a developed model. Different block copolymers compositions were synthesized by varying the switching time of the substrate pulses responsible for block copolymer synthesis. The block copolymers were tested to determine their chemical properties and cast into films to determine the materials properties. These block copolymer films possessed new properties not achieved by copolymers or blends of the two polymers.

  15. Model for Quality Control of Allergen Products with Mass Spectrometry.

    Science.gov (United States)

    Spiric, Jelena; Schulenborg, Thomas; Schwaben, Luisa; Engin, Anna M; Karas, Michael; Reuter, Andreas

    2017-10-06

    Birch pollen allergy is diagnosed and treated with aqueous extracts from birch pollen, which contain a mixture of allergens and nonallergenic proteins, including large numbers of closely related sequence variants, so-called iso-allergens of the major allergen, Bet v 1. The quality of therapeutic and diagnostic allergen products largely depends on the allergen and iso-allergen composition. Several biochemical methods are currently applied to detect and quantify allergens and to record protein profiles without differentiating between iso-allergens. Mass spectrometry (MS) may entirely replace these technologies, as it allows sequence specific identification and quantification of proteins and protein profiles including sequence variants in one run. However, the protein inference problem still hampers the automatic assignment of peptide sequences to proteins, consequently impeding the quantification of sequence variants. Therefore, the aim of the study was to set up semitargeted analyses of label-free MS data that allow unambiguous identification and quantification of birch pollen allergens and nonallergenic proteins. We combined data independent acquisition with manual assignment of predefined target sequences for quantification of iso-allergens and automatic quantification of other allergens and nonallergenic proteins. The quantitative data for birch pollen allergens and sequence variants of Bet v 1 were further confirmed by multiple reaction monitoring.

  16. Fast multi-blind modification search through tandem mass spectrometry.

    Science.gov (United States)

    Na, Seungjin; Bandeira, Nuno; Paek, Eunok

    2012-04-01

    With great biological interest in post-translational modifications (PTMs), various approaches have been introduced to identify PTMs using MS/MS. Recent developments for PTM identification have focused on an unrestrictive approach that searches MS/MS spectra for all known and possibly even unknown types of PTMs at once. However, the resulting expanded search space requires much longer search time and also increases the number of false positives (incorrect identifications) and false negatives (missed true identifications), thus creating a bottleneck in high throughput analysis. Here we introduce MODa, a novel "multi-blind" spectral alignment algorithm that allows for fast unrestrictive PTM searches with no limitation on the number of modifications per peptide while featuring over an order of magnitude speedup in relation to existing approaches. We demonstrate the sensitivity of MODa on human shotgun proteomics data where it reveals multiple mutations, a wide range of modifications (including glycosylation), and evidence for several putative novel modifications. Based on the reported findings, we argue that the efficiency and sensitivity of MODa make it the first unrestrictive search tool with the potential to fully replace conventional restrictive identification of proteomics mass spectrometry data.

  17. Uranium quantification in semen by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Todorov, Todor; Ejnik, John W.; Guandalini, Gustavo S.; Xu, Hanna; Hoover, Dennis; Anderson, Larry W.; Squibb, Katherine; McDiarmid, Melissa A.; Centeno, Jose A.

    2013-01-01

    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2 g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4–7% RSD and spike recoveries were 97–100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n = 10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans’ semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments.

  18. Analytical Properties of Solid-substrate Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Hu, Bin; So, Pui-Kin; Yao, Zhong-Ping

    2013-01-01

    Conventional electrospray ionization mass spectrometry (ESI-MS) uses a capillary for sample loading and ionization. Along with the development of ambient ionization techniques, ESI-MS using noncapillary emitters has attracted more interest in recent years. Following our recent report on ESI-MS using wooden tips ( Anal. Chem. 83, 8201-8207 (2011)), the technique was further investigated and extended in this study. Our results revealed that the wooden tips could serve as a chromatographic column for separation of sample components. Sequential and exhaustive ionization was observed for proteins and salts on wooden tips with salts ionized sooner and proteins later. Nonconductive materials that contain microchannels/pores could be used as tips for ESI-MS analysis with sample solutions loaded to the sharp-ends only, since rapid diffusion of sample solutions by capillary action would enable the tips to become conductive. Tips of inert materials such as bamboo, fabrics, and sponge could be used for sample loading and ionization, while samples such as tissue, mushroom, and bone could form tips to induce ionization for direct analysis with application of a high voltage. [Figure not available: see fulltext.

  19. Supercharging with Trivalent Metal Ions in Native Mass Spectrometry

    Science.gov (United States)

    Flick, Tawnya G.; Williams, Evan R.

    2012-11-01

    Addition of 1.0 mM LaCl3 to aqueous ammonium acetate solutions containing proteins in their folded native forms can result in a significant increase in the molecular ion charging obtained with electrospray ionization as a result of cation adduction. In combination with m-nitrobenzyl alcohol, molecular ion charge states that are greater than the number of basic sites in the protein can be produced from these native solutions, even for lysozyme, which is conformationally constrained by four intramolecular disulfide bonds. Circular dichroism spectroscopy indicates that the conformation of ubiquitin is not measurably affected with up to 1.0 M LaCl3, but ion mobility data indicate that the high charge states that are formed when 1.0 mM LaCl3 is present are more unfolded than the low charge states formed without this reagent. These and other results indicate that the increased charging is a result of La3+ preferentially adducting onto compact or more native-like conformers during ESI and the gas-phase ions subsequently unfolding as a result of increased Coulomb repulsion. Electron capture dissociation of these high charge-state ions formed from these native solutions results in comparable sequence coverage to that obtained for ions formed from denaturing solutions without supercharging reagents, making this method a potentially powerful tool for obtaining structural information in native mass spectrometry.

  20. Fast Multi-blind Modification Search through Tandem Mass Spectrometry*

    Science.gov (United States)

    Na, Seungjin; Bandeira, Nuno; Paek, Eunok

    2012-01-01

    With great biological interest in post-translational modifications (PTMs), various approaches have been introduced to identify PTMs using MS/MS. Recent developments for PTM identification have focused on an unrestrictive approach that searches MS/MS spectra for all known and possibly even unknown types of PTMs at once. However, the resulting expanded search space requires much longer search time and also increases the number of false positives (incorrect identifications) and false negatives (missed true identifications), thus creating a bottleneck in high throughput analysis. Here we introduce MODa, a novel “multi-blind” spectral alignment algorithm that allows for fast unrestrictive PTM searches with no limitation on the number of modifications per peptide while featuring over an order of magnitude speedup in relation to existing approaches. We demonstrate the sensitivity of MODa on human shotgun proteomics data where it reveals multiple mutations, a wide range of modifications (including glycosylation), and evidence for several putative novel modifications. Based on the reported findings, we argue that the efficiency and sensitivity of MODa make it the first unrestrictive search tool with the potential to fully replace conventional restrictive identification of proteomics mass spectrometry data. PMID:22186716

  1. Detection of {sup 59}Ni by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Per; Erlandsson, Bengt; Freimann, K.; Hellborg, R.; Stenstroem, K. [Lund Univ. (Sweden). Dept. of Nuclear Physics; Larsson, Ragnar [Lund Univ. (Sweden). Chemical Engineering II; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology

    1999-02-01

    The aims of this project were to develop a method to measure the amount of {sup 59}Ni in stainless steel and to determine the detection limit for this method. {sup 59}Ni is produced by neutron activation in the construction material close to the core in a nuclear reactor and it is important to know the amount of {sup 59}Ni present as it governs the classification of the waste. If the amount of {sup 59}Ni is known at different locations in relation to the core, it is also possible to refine the calculation models of the neutron flux in the reactor. Accelerator mass spectrometry, an ultra-sensitive method for measuring small concentrations of radionuclides as well as stable nuclides, has been used in this investigation to determine the concentration of {sup 59}Ni (and thereby the activity) in stainless steel. As the cobalt content in stainless steel is the main contributor to the background in a measurement of {sup 59}Ni, a method for the chemical extraction of nickel from stainless steel, including a purification step to reduce the cobalt content in the sample, has been developed. The detection limit for {sup 59}Ni has been determined to 100{+-}30 Bq per gram nickel (100{+-}30 Bq/g) with the present status of the system 14 refs, 6 figs, 3 tabs

  2. Neurological analyses: focus on gangliosides and mass spectrometry.

    Science.gov (United States)

    Zamfir, Alina D

    2014-01-01

    Gangliosides, sialylated glycosphingolipids, are particularly enriched in mammalian central nervous system where their expression is cell type-specific and changes particularly during brain development, maturation, aging, and diseases. For this reason, gangliosides are important diagnostic markers for various brain ailments, including primary and secondary brain tumors and neurodegenerative diseases. Among all biochemical and biophysical methods employed so far for ganglioside analysis, mass spectrometry (MS) emerged as one of the most reliable due to the sensitivity, accuracy, and speed of analysis as well as the possibility to characterize in details the molecular structure of the identified biomarkers.This chapter presents significant achievements of MS with either electrospray (ESI), chip-based ESI, or matrix-assisted laser desorption/ionization (MALDI) in the analysis of gangliosides in normal and diseased human brain. Specifically, the chapter assesses the MS contribution in determination of topospecificity, filogenetic, and brain development stage dependence of ganglioside composition and structure as well as in discovery of ganglioside markers in neurodegenerative/neurodevelopmental conditions, primary and secondary brain tumors. The highlighted accomplishments in characterization of novel structures associated to severe brain pathologies show that MS has real perspectives to become a routine method for early diagnosis and therapy based on this biomolecule class.

  3. Capillary electrophoresis-mass spectrometry for glycoscreening in biomedical research.

    Science.gov (United States)

    Zamfir, Alina; Peter-Katalinić, Jasna

    2004-07-01

    Application of capillary electrophoresis (CE) in combination with mass spectrometry (MS) and tandem MS to glycoscreening in biomedical projects is highlighted. In the first part recent CE-MS experiments by sheath liquid CE and multiple stage MS are reported. Neutral and negatively charged N-glycan mixtures from ribonuclease B and fetuin, high-mannose type N-glycoforms, oligosaccharides from lipopolysaccharides (LPS) of Haemophilus influenzae, polysaccharides of Pseudomonas aeruginosa and Staphylococcus aureus were analyzed. A particular emphasis is devoted to the applicability of novel off- and on-line CE-MS and tandem MS methods for screening of proteoglycan-derived oligosaccharides, glycosaminoglycans (GAGs), such as hyaluronates from Streptococcus agalactiae, chondroitin/dermatan sulfates (CS/DS) from bovine aorta and human skin fibroblast decorin, and heparin/heparan sulfate (HS) from porcine and bovine mucosa. The performance of CE-MS/MS for identification of glycoforms in glycopeptides and glycoproteins is illustrated by experiments performed on complex mixtures from urine of patients suffering from a hereditary N-acetylhexosaminidase deficiency (Schindler's disease) and urine of patients suffering from cancer cachexia. For determination of glycosylation patterns in glycoproteins like enzymes and antibodies by CE/MS, both CE-matrix assisted laser desorption/ionization (MALDI) and CE-electrospray ionization (ESI)-MS were functional. Finally, the potential of CE-ESI-MS strategy in glycolipid analysis is demonstrated for gangliosides from bovine brain for which particular CE buffer conditions are required.

  4. Cold-spray ionization mass spectrometry: principle and applications.

    Science.gov (United States)

    Yamaguchi, Kentaro

    2003-05-01

    A direct solution analysis method, cold-spray ionization (CSI) mass spectrometry (MS), a variant of electrospray (ESI) MS operating at low temperature (ca -80 to 10 degrees C), allows the facile and precise characterization of labile organic species, especially those in which non-covalent bonding interactions are prominent. We applied this method to investigations of the solution structures of many labile organic species, including unstable reagents and reaction intermediates, asymmetric catalysts, supramolecules and even primary biomolecules. Remarkable analytical results were obtained for highly ordered supramolecules using the CSI method. Whereas conventional ESI is not applicable to these compounds because of their instability to heat and/or air, CSI affords multiply charged molecular ions with many solvent molecules attached. Investigation of the constitution of Grignard reagents in solution is extremely challenging, but CSI-MS allowed us to identify one of the key structures in THF solution. Recently, this method was adopted for investigations of the solution structures of primary biomolecules such as nucleosides, amino acids, sugars and lipids, revealing singly charged Na(+) adducts of large clusters (chain structures), presumably linked by non-covalent interactions, including hydrogen bonding and/or hydrophobic interactions. The principle of the CSI method and applications of the method to a wide variety of labile organic species and primary biomolecules in solution are described. Copyright 2003 John Wiley & Sons, Ltd.

  5. Mapping the Small Molecule Interactome by Mass Spectrometry.

    Science.gov (United States)

    Flaxman, Hope A; Woo, Christina M

    2018-01-16

    Mapping small molecule interactions throughout the proteome provides the critical structural basis for functional analysis of their impact on biochemistry. However, translation of mass spectrometry-based proteomics methods to directly profile the interaction between a small molecule and the whole proteome is challenging because of the substoichiometric nature of many interactions, the diversity of covalent and noncovalent interactions involved, and the subsequent computational complexity associated with their spectral assignment. Recent advances in chemical proteomics have begun fill this gap to provide a structural basis for the breadth of small molecule-protein interactions in the whole proteome. Innovations enabling direct characterization of the small molecule interactome include faster, more sensitive instrumentation coupled to chemical conjugation, enrichment, and labeling methods that facilitate detection and assignment. These methods have started to measure molecular interaction hotspots due to inherent differences in local amino acid reactivity and binding affinity throughout the proteome. Measurement of the small molecule interactome is producing structural insights and methods for probing and engineering protein biochemistry. Direct structural characterization of the small molecule interactome is a rapidly emerging area pushing new frontiers in biochemistry at the interface of small molecules and the proteome.

  6. Quantitation of soybean allergens using tandem mass spectrometry.

    Science.gov (United States)

    Houston, Norma L; Lee, Dong-Gi; Stevenson, Severin E; Ladics, Gregory S; Bannon, Gary A; McClain, Scott; Privalle, Laura; Stagg, Nicola; Herouet-Guicheney, Corinne; MacIntosh, Susan C; Thelen, Jay J

    2011-02-04

    Soybean (Glycine max) seed contain some proteins that are allergenic to humans and animals. However, the concentration of these allergens and their expression variability among germplasms is presently unknown. To address this problem, 10 allergens were quantified from 20 nongenetically modified commercial soybean varieties using parallel, label-free mass spectrometry approaches. Relative quantitation was performed by spectral counting and absolute quantitation was performed using multiple reaction monitoring (MRM) with synthetic, isotope-labeled peptides as internal standards. During relative quantitation analysis, 10 target allergens were identified, and five of these allergens showed expression levels higher than technical variation observed for bovine serum albumin (BSA) internal standard (∼11%), suggesting expression differences among the varieties. To confirm this observation, absolute quantitation of these allergens from each variety was performed using MRM. Eight of the 10 allergens were quantified for their concentration in seed and ranged from approximately 0.5 to 5.7 μg/mg of soy protein. MRM analysis reduced technical variance of BSA internal standards to approximately 7%, and confirmed differential expression for four allergens across the 20 varieties. This is the first quantitative assessment of all major soybean allergens. The results show the total quantity of allergens measured among the 20 soy varieties was mostly similar.

  7. Inductively coupled plasma - mass spectrometry - status, usability and regulatory acceptance

    Energy Technology Data Exchange (ETDEWEB)

    Wyrick, S.B. [SAIC, Gaithersburg, MD (United States)

    1995-12-01

    Analytical methods utilizing Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) are still relatively new to the regulatory community. The scientific community continues to utilize ICP-MS methods and to develop innovative upgrades to in the areas of on-line column separations and preconcentration, enhanced nebulization and sample introduction techniques, and improved collector hardware for improved resolution, sensitivity and matrix effect corrections. The U.S. Environmental Protection Agency (EPA) and American Society for Testing and Materials (ASTM) have produced draft methods for ICP-MS operations. The methods are generally nonspecific and may not apply to actinide determinations. The Analytical Services Division (EM- 263) of Department of Energy (DOE) Office of Environmental Management (EM) has developed a compendium of analytical methods titled, DOE Methods for Evaluating Environmental and Waste Management Samples. The purpose of this compendium is to provide and up-to-date reference for analytical procedures for DOE Nuclear Weapons Complex (NWC) applications, and to provide a placeholder for SOPs prior to inclusion in other national standards.

  8. Cationic Xylene Tag for Increasing Sensitivity in Mass Spectrometry

    Science.gov (United States)

    Wang, Poguang; Zhang, Qi; Yao, Yuanyuan; Giese, Roger W.

    2015-06-01

    N-(2-(Bromomethyl)benzyl)-N,N-diethylethanaminium bromide, that we designate as CAX-B (cationic xylyl-bromide), is presented as a derivatization reagent for increasing sensitivity in mass spectrometry. Because of its aryl bromomethyl moiety, CAX-B readily labels compounds having an active hydrogen. In part, a CAX-tagged analyte (CAX-analyte) can be very sensitive especially in a tandem mass spectrometer (both ESI and MALDI). This is because of facile formation of an analyte-characteristic first product ion (as a xylyl-based cation) from favorable loss of triethylamine as a neutral from the precursor ion. This loss is enhanced both by resonance stabilization of the xylyl cation, and by anchimeric assistance from the ortho hetero atom of the attached analyte. High intensity of a first product ion opens up the opportunity for a CAX-analyte to be additionally sensitive when it is prone to a secondary neutral loss from the analyte part. For example, we have derivatized and detected 160 amol of thymidine by CAX-tagging/LC-MALDI-TOF/TOF-MS in this way, where the two neutral losses are triethylamine and deoxyribose. Other analytes detected at the amol level as CAX derivatives (as diluted standards) include estradiol and some nucleobases. The tendency for analytes with multiple active hydrogens to label just once with CAX (an advantage) is illustrated by the conversion of bisphenol A to a single product even when excess CAX-B is present. A family of analogous reagents with a variety of reactivity groups is anticipated as a consequence of replacing the bromine atom of CAX-B with various functional groups.

  9. Mass Spectrometry Imaging for the Investigation of Intratumor Heterogeneity.

    Science.gov (United States)

    Balluff, B; Hanselmann, M; Heeren, R M A

    2017-01-01

    One of the big clinical challenges in the treatment of cancer is the different behavior of cancer patients under guideline therapy. An important determinant for this phenomenon has been identified as inter- and intratumor heterogeneity. While intertumor heterogeneity refers to the differences in cancer characteristics between patients, intratumor heterogeneity refers to the clonal and nongenetic molecular diversity within a patient. The deciphering of intratumor heterogeneity is recognized as key to the development of novel therapeutics or treatment regimens. The investigation of intratumor heterogeneity is challenging since it requires an untargeted molecular analysis technique that accounts for the spatial and temporal dynamics of the tumor. So far, next-generation sequencing has contributed most to the understanding of clonal evolution within a cancer patient. However, it falls short in accounting for the spatial dimension. Mass spectrometry imaging (MSI) is a powerful tool for the untargeted but spatially resolved molecular analysis of biological tissues such as solid tumors. As it provides multidimensional datasets by the parallel acquisition of hundreds of mass channels, multivariate data analysis methods can be applied for the automated annotation of tissues. Moreover, it integrates the histology of the sample, which enables studying the molecular information in a histopathological context. This chapter will illustrate how MSI in combination with statistical methods and histology has been used for the description and discovery of intratumor heterogeneity in different cancers. This will give evidence that MSI constitutes a unique tool for the investigation of intratumor heterogeneity, and could hence become a key technology in cancer research. © 2017 Elsevier Inc. All rights reserved.

  10. Mass spectrometry-based proteomic analyses of contact lens deposition.

    Science.gov (United States)

    Green-Church, Kari B; Nichols, Jason J

    2008-02-08

    The purpose of this report is to describe the contact lens deposition proteome associated with two silicone hydrogel contact lenses and care solutions using a mass spectrometric-based approach. This was a randomized, controlled, examiner-masked crossover clinical trial that included 48 participants. Lenses and no-rub care solutions evaluated included galyfilcon A (Acuvue Advance, Vistakon Inc., Jacksonville, FL), lotrafilcon B (O2 Optix, CIBA Vision Inc., Duluth, GA), AQuify (CIBA Vision Inc.), and ReNu MoistureLoc (Bausch and Lomb Inc., Rochester, NY). After two weeks of daily wear in each lens-solution combination, the left lens was removed by the examiner (using gloves and forceps) and placed in a protein precipitation buffer (acetone). The precipitate was quantitated for total protein concentration (per lens), and proteins were then identified using liquid chromatography tandem mass spectrometry (nano-LC-MS/MS) and peptide sequencing. Between 7.32 and 9.76 microg/lens of protein was observed on average from each lens-solution combination. There were 19 total unique proteins identified across the two lens materials, and six proteins were identified in all four lens-solution combinations including lipocalin, lysozyme, lacritin, lactoferrin, proline rich 4, and Ig Alpha. Lotrafilcon B was associated with 15 individual proteins (across both care solutions), and 53% of these proteins were observed in at least 50% of the analyses. Galyfilcon A was associated with 13 individual proteins, and 38.5% of these proteins were observed in at least 50% of the analyses. There were three unique proteins identified from galyfilcon A and four unique proteins identified from lotrafilcon B. The total amount of proteins identified from silicone hydrogel materials is much less than the amount from traditional soft lens materials. For the most part, the deposition proteome across these lenses is similar, although the different polymer characteristics might be associated with some

  11. Analysis of overlapped and noisy hydrogen/deuterium exchange mass spectra.

    Science.gov (United States)

    Guttman, Miklos; Weis, David D; Engen, John R; Lee, Kelly K

    2013-12-01

    Noisy and overlapped mass spectrometry data hinder the sequence coverage that can be obtained from hydrogen deuterium exchange analysis, and places a limit on the complexity of the samples that can be studied by this technique. Advances in instrumentation have addressed these limits, but as the complexity of the biological samples under investigation increases, these problems are re-encountered. Here we describe the use of binomial distribution fitting with asymmetric linear squares regression for calculating the accurate deuterium content for mass envelopes of low signal or that contain significant overlap. The approach is demonstrated with a test data set of HIV Env gp140 wherein inclusion of the new analysis regime resulted in obtaining exchange data for 42 additional peptides, improving the sequence coverage by 11%. At the same time, the precision of deuterium uptake measurements was improved for nearly every peptide examined. The improved processing algorithms also provide an efficient method for deconvolution of bimodal mass envelopes and EX1 kinetic signatures. All these functions and visualization tools have been implemented in the new version of the freely available software, HX-Express v2.

  12. Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Shi, Y; Dai, X; Collins, R; Kramer-Tremblay, S

    2011-08-01

    Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency.

  13. Analysis of triazines and associated metabolites with electrospray ionization field-asymmetric ion mobility spectrometry/mass spectrometry

    DEFF Research Database (Denmark)

    Mie, Axel; Sandulescu, Madaline; Mathiasson, Lennart

    2008-01-01

    Triazines comprise an important pollutant class owing to continued use in certain countries, and owing to strong environmental persistence that leads to problems even in countries like Sweden where the use of triazines has been prohibited for some years. We investigated mass-selective detection...... for analysis of triazines. More specifically, we studied the background reduction and sensitivity enhancement that result from the use of a new interface technique, field-asymmetric ion mobility spectrometry (FAIMS), in conjunction with electrospray ionization ion-trap mass spectrometry. This technique allows...

  14. Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    van Agthoven, Maria A; Barrow, Mark P; Chiron, Lionel; Coutouly, Marie-Aude; Kilgour, David; Wootton, Christopher A; Wei, Juan; Soulby, Andrew; Delsuc, Marc-André; Rolando, Christian; O'Connor, Peter B

    2015-12-01

    Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules. Graphical Abstract ᅟ.

  15. Application of MALDI-triple quadrupole mass spectrometry for the quantification of small molecules in biomedical research

    NARCIS (Netherlands)

    R.J.W. Meesters (Roland)

    2011-01-01

    textabstractA century after its introduction, mass spectrometry is still an innovative technology, which, due to continuous instrumental developments and improvements, has provided important scientific insights in biochemistry, molecular biology and medicine. Now, in 2011, mass spectrometry is used

  16. Characterization of Nitrated Sugar Alcohols by Atmospheric-Pressure Chemical-Ionization Mass Spectrometry

    Science.gov (United States)

    2016-07-27

    mass spectrometry (APCI-MS) was used to detect ions characteristic of nitrated sugar alcohols. Time-of- flight APCI mass spectrometry (TOF APCI-MS...disclosed here will benefit the area of explosives trace detection for counterterrorism and forensics. INTRODUCTION The military-grade...with an Agilent 6520 QTOF quadrupole time-of- flight (TOF) mass spectrometer (Agilent technologies, Santa Clara, CA, USA) equipped with an APCI source

  17. Inductively Coupled Plasma Mass Spectrometry: Sample Analysis of Zirconium and Ruthenium in Metal Organic Frameworks

    Science.gov (United States)

    2018-02-01

    INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY: SAMPLE ANALYSIS OF ZIRCONIUM AND RUTHENIUM IN METAL ORGANIC...MM-YYYY) XX-02-2018 2. REPORT TYPE Final 3. DATES COVERED (From - To) Aug 2016–Aug 2017 4. TITLE AND SUBTITLE Inductively Coupled Plasma Mass...MOFs) using inductively coupled plasma mass spectrometry (ICP–MS). Specifically, the MOFs were analyzed for the zirconium-to-ruthenium ratios. The

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

    Science.gov (United States)

    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.

  19. Mass exchanger for high-rise buildings with aquifer storage

    Energy Technology Data Exchange (ETDEWEB)

    Tolido, H.W.A.; Veltkamp, W.B.; Schaap, A.B. [LEVEL Energy Technology, Son (Netherlands)

    1994-12-31

    Aquifer storage systems are used to withdraw cold in summer and heat in winter. In high-rise buildings the technical installations are preferably placed on the top floor and so water from the aquifer has to be pressurised. Heat is absorbed or released here and the water returns to the aquifer. To recover potential energy from the pressurised water a turbine-pump combination may be used or the high pressure circuit is separated from the low pressure circuit by a heat exchanger. Van Berkel (1991) found that turbine-pump combinations recover only about 25-40 % of the potential energy. Application of a heat exchanger typically shows a thermal efficiency of 80 %. The proposed mass exchanger combines pressure separation with high effective heat transport. The high pressure circuit in the building and the low pressure aquifer circuit, are separated by a rotating element with rotation symmetric distributed chambers. Chunks of water are cut from the high pressure circuit and rotated into the low pressure circuit while at the same time an equal amount of water is transported from the low into the high pressure circuit. In these chambers also separation of warm and cold water is realised, due to the plug flow. Testing a scale model demonstrated the feasibility of the design, indicating a pressure recovery and thermal effectivity of the apparatus of 99 % and of 96 %. (orig.)

  20. Structural Characterization of Anticancer Drug Paclitaxel and Its Metabolites Using Ion Mobility Mass Spectrometry and Tandem Mass Spectrometry

    Science.gov (United States)

    Lee, Hong Hee; Hong, Areum; Cho, Yunju; Kim, Sunghwan; Kim, Won Jong; Kim, Hugh I.

    2016-02-01

    Paclitaxel (PTX) is a popular anticancer drug used in the treatment of various types of cancers. PTX is metabolized in the human liver by cytochrome P450 to two structural isomers, 3'- p-hydroxypaclitaxel (3 p-OHP) and 6α-hydroxypaclitaxel (6α-OHP). Analyzing PTX and its two metabolites, 3 p-OHP and 6α-OHP, is crucial for understanding general pharmacokinetics, drug activity, and drug resistance. In this study, electrospray ionization ion mobility mass spectrometry (ESI-IM-MS) and collision induced dissociation (CID) are utilized for the identification and characterization of PTX and its metabolites. Ion mobility distributions of 3 p-OHP and 6α-OHP indicate that hydroxylation of PTX at different sites yields distinct gas phase structures. Addition of monovalent alkali metal and silver metal cations enhances the distinct dissociation patterns of these structural isomers. The differences observed in the CID patterns of metalated PTX and its two metabolites are investigated further by evaluating their gas-phase structures. Density functional theory calculations suggest that the observed structural changes and dissociation pathways are the result of the interactions between the metal cation and the hydroxyl substituents in PTX metabolites.