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Journal of the American Society for Mass Spectrometry

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https://www.readbyqxmd.com/read/29043486/study-of-in-trap-ion-clouds-by-ion-trajectory-simulations
#1
Xiaoyu Zhou, Xinwei Liu, Wenbo Cao, Xiao Wang, Ming Li, Haoxue Qiao, Zheng Ouyang
Gaussian distribution has been utilized to describe the global number density distribution of ion cloud in the Paul trap, which is known as the thermal equilibrium theory and widely used in theoretical modeling of ion clouds in the ion traps. Using ion trajectory simulations, however, the ion clouds can now also be treated as a dynamic ion flow field and the location-dependent features could now be characterized. This study was carried out to better understand the in-trap ion cloud properties, such as the local particle velocity and temperature...
October 17, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038998/effect-of-electrode-geometry-on-the-classification-performance-of-rapid-evaporative-ionization-mass-spectrometric-reims-bacterial-identification
#2
Zsolt Bodai, Simon Cameron, Frances Bolt, Daniel Simon, Richard Schaffer, Tamas Karancsi, Julia Balog, Tony Rickards, Adam Burke, Kate Hardiman, Julia Abda, Monica Rebec, Zoltan Takats
The recently developed automated, high-throughput monopolar REIMS platform is suited for the identification of clinically important microorganisms. Although already comparable to the previously reported bipolar forceps method, optimization of the geometry of monopolar electrodes, at the heart of the system, holds the most scope for further improvements to be made. For this, sharp tip and round shaped electrodes were optimized to maximize species-level classification accuracy. Following optimization of the distance between the sample contact point and tube inlet with the sharp tip electrodes, the overall cross-validation accuracy improved from 77% to 93% in negative and from 33% to 63% in positive ion detection modes, compared with the original 4 mm distance electrode...
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038997/multiparticle-simulations-of-quadrupolar-ion-detection-in-an-ion-cyclotron-resonance-cell-with-four-narrow-aperture-detection-electrodes
#3
Joshua A Driver, Konstantin O Nagornov, Anton N Kozhinov, Yury O Tsybin, Andriy Kharchenko, I Jonathan Amster
The current paradigm in FT-ICR cell design is to approximate the ideal three-dimensional quadratic trapping potential as closely as possible to maintain ion cloud spatial coherence and achieve long transients, either with hyperbolically shaped electrodes, shimming electrodes, or by dynamic harmonization. In sharp contrast, the FT-ICR analyzer cell with four narrow aperture detection electrodes (NADEL) introduces significant anharmonic terms to the trapping potential. This analyzer cell is capable of quadrupolar detection by which one can measure a signal that is close to the unperturbed cyclotron frequency...
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038996/combining-structural-probes-in-the-gas-phase-ion-mobility-resolved-action-fret
#4
Steven Daly, Luke MacAleese, Philippe Dugourd, Fabien Chirot
In the context of native mass spectrometry, the development of gas-phase structural probes sensitive to the different levels of structuration of biomolecular assemblies is necessary to push forward conformational studies. In this paper, we provide the first example of the combination of ion mobility (IM) and Förster resonance energy transfer (FRET) measurements within the same experimental setup. The possibility to obtain mass- and mobility-resolved FRET measurements is demonstrated on a model peptide and applied to monitor the collision-induced unfolding of ubiquitin...
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038995/characterization-and-analysis-of-paper-spray-ionization-of-organic-compounds
#5
Hugo Aliaga-Aguilar
Paper spray ionization has arisen relatively recently as a complement and alternative to electro- and nanospray ionization with silica capillaries. A majority of the work in the present literature focuses on the chemical aspect of paper spray. In order to study the physical and phenomenological facet of its implementation, we measured current and voltage distributions of Taylor cones. To study transport phenomena on filter paper, we addressed the behavior of large, sparingly soluble tetraalkylammonium ions, which are usually used as mobility standards, in paper spray...
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038994/reply-to-the-comment-on-nominal-mass-by-athula-b-attygalle-and-julius-pavlov-j-am-soc-mass-spectrom-28-1737-1738-2017
#6
Athula B Attygalle, Julius Pavlov
No abstract text is available yet for this article.
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29038993/the-ups-and-downs-of-repeated-cleavage-and-internal-fragment-production-in-top-down-proteomics
#7
Yana A Lyon, Dylan Riggs, Luca Fornelli, Philip D Compton, Ryan R Julian
Analysis of whole proteins by mass spectrometry, or top-down proteomics, has several advantages over methods relying on proteolysis. For example, proteoforms can be unambiguously identified and examined. However, from a gas-phase ion-chemistry perspective, proteins are enormous molecules that present novel challenges relative to peptide analysis. Herein, the statistics of cleaving the peptide backbone multiple times are examined to evaluate the inherent propensity for generating internal versus terminal ions...
October 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29027151/comparison-of-different-ion-mobility-setups-using-poly-ethylene-oxide-peo-polymers-drift-tube-tims-and-t-wave
#8
Jean R N Haler, Philippe Massonnet, Fabien Chirot, Christopher Kune, Clothilde Comby-Zerbino, Jan Jordens, Maarten Honing, Ynze Mengerink, Johann Far, Philippe Dugourd, Edwin De Pauw
Over the years, polymer analyses using ion mobility-mass spectrometry (IM-MS) measurements have been performed on different ion mobility spectrometry (IMS) setups. In order to be able to compare literature data taken on different IM(-MS) instruments, ion heating and ion temperature evaluations have already been explored. Nevertheless, extrapolations to other analytes are difficult and thus straightforward same-sample instrument comparisons seem to be the only reliable way to make sure that the different IM(-MS) setups do not greatly change the gas-phase behavior...
October 12, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29027149/sequencing-larger-intact-proteins-30-70-kda-with-activated-ion-electron-transfer-dissociation
#9
Nicholas M Riley, Michael S Westphall, Joshua J Coon
The analysis of intact proteins via mass spectrometry can offer several benefits to proteome characterization, although the majority of top-down experiments focus on proteoforms in a relatively low mass range (<30 kDa). Recent studies have focused on improving the analysis of larger intact proteins (up to ~75 kDa), but they have also highlighted several challenges to be addressed. One major hurdle is the efficient dissociation of larger protein ions, which often to do not yield extensive fragmentation via conventional tandem MS methods...
October 12, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29027132/submicrometer-emitter-esi-tips-for-native-mass-spectrometry-of-membrane-proteins-in-ionic-and-nonionic-detergents
#10
Anna C Susa, Jennifer L Lippens, Zijie Xia, Joseph A Loo, Iain D G Campuzano, Evan R Williams
Native mass spectrometry (native-MS) of membrane proteins typically requires a detergent screening protocol, protein solubilization in the preferred detergent, followed by protein liberation from the micelle by collisional activation. Here, submicrometer nano-ESI emitter tips are used for native-MS of membrane proteins solubilized in both nonionic and ionic detergent solutions. With the submicrometer nano-ESI emitter tips, resolved charge-state distributions of membrane protein ions are obtained from a 150 mM NaCl, 25 mM Tris-HCl with 1...
October 12, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29027129/protein-glass-surface-interactions-and-ion-desalting-in-electrospray-ionization-with-submicron-emitters
#11
Zije Xia, Evan R Williams
Theta glass electrospray emitters can rapidly mix solutions to investigate fast reactions that occur as quickly as 1 μs, but emitters with submicron tips have the unusual properties of desalting protein ions and affecting the observed abundances of some proteins as a result of protein-surface interactions. The role of protein physical properties on ion signal was investigated using 1.7 ± 0.1 μm and 269 ± 7 nm emitters and 100 mM aqueous ammonium acetate or ammonium bicarbonate solutions. Protein ion desalting occurs for both positive and negative ions...
October 12, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28980177/ultraviolet-infrared-and-high-low-energy-photodissociation-of-post-translationally-modified-peptides
#12
Mohammad A Halim, Luke MacAleese, Jérôme Lemoine, Rodolphe Antoine, Philippe Dugourd, Marion Girod
Mass spectrometry-based methods have made significant progress in characterizing post-translational modifications in peptides and proteins; however, certain aspects regarding fragmentation methods must still be improved. A good technique is expected to provide excellent sequence information, locate PTM sites, and retain the labile PTM groups. To address these issues, we investigate 10.6 μm IRMPD, 213 nm UVPD, and combined UV and IR photodissociation, known as HiLoPD (high-low photodissociation), for phospho-, sulfo-, and glyco-peptide cations...
October 4, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28975559/bottom-up-two-dimensional-electron-capture-dissociation-mass-spectrometry-of-calmodulin
#13
Federico Floris, Maria A van Agthoven, Lionel Chiron, Christopher A Wootton, Pui Yiu Yuko Lam, Mark P Barrow, Marc-André Delsuc, Peter B O'Connor
Two-dimensional mass spectrometry (2D MS) is a tandem mass spectrometry technique that allows data-independent fragmentation of all precursors in a mixture without previous isolation, through modulation of the ion cyclotron frequency in the ICR-cell prior to fragmentation. Its power as an analytical technique has been proven particularly for proteomics. Recently, a comparison study between 1D and 2D MS has been performed using infrared multiphoton dissociation (IRMPD) on calmodulin (CaM), highlighting the capabilities of the technique in both top-down (TDP) and bottom-up proteomics (BUP)...
October 3, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28971440/probing-conformational-dynamics-of-tau-protein-by-hydrogen-deuterium-exchange-mass-spectrometry
#14
Richard Y-C Huang, Roxana E Iacob, Sethu Sankaranarayanan, Ling Yang, Michael Ahlijanian, Li Tao, Adrienne A Tymiak, Guodong Chen
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...
October 2, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28971374/flying-cages-in-traveling-wave-ion-mobility-influence-of-the-instrumental-parameters-on-the-topology-of-the-host-guest-complexes
#15
Glenn Carroy, Vincent Lemaur, Céline Henoumont, Sophie Laurent, Julien De Winter, Edwin De Pauw, Jérôme Cornil, Pascal Gerbaux
Supramolecular mass spectrometry has emerged in the last decade as an orthogonal method to access, at the molecular level, the structures of noncovalent complexes extracted from the condensed phase to the rarefied gas phase using electrospray ionization. It is often considered that the soft nature of the ESI source confers to the method the capability to generate structural data comparable to those in the condensed phase. In the present paper, using the ammonium ion/cucurbituril combination as a model system, we investigate using ion mobility and computational chemistry the influence of the instrumental parameters on the topology, i...
October 2, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28971338/fourier-transform-ion-cyclotron-resonance-mass-spectrometry-as-a-platform-for-characterizing-multimeric-membrane-protein-complexes
#16
Jennifer L Lippens, Michael Nshanian, Chris Spahr, Pascal F Egea, Joseph A Loo, Iain D G Campuzano
Membrane protein characterization is consistently hampered by challenges with expression, purification, and solubilization. Among several biophysical techniques employed for their characterization, native-mass spectrometry (MS) has emerged as a powerful tool for the analysis of membrane proteins and complexes. Here, two MS platforms, the FT-ICR and Q-ToF, have been explored to analyze the homotetrameric water channel protein, AquaporinZ (AqpZ), under non-denaturing conditions. This 97 kDa membrane protein complex can be readily liberated from the octylglucoside (OG) detergent micelle under a range of instrument conditions on both MS platforms...
October 2, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28971335/digital-waveform-technology-and-the-next-generation-of-mass-spectrometers
#17
Nathan M Hoffman, Zachary P Gotlib, Bojana Opačić, Adam P Huntley, Ashley M Moon, Katherine E G Donahoe, Gregory F Brabeck, Peter T A Reilly
Ion traps and guides are integral parts of current commercial mass spectrometers. They are currently operated with sinusoidal waveform technology that has been developed over many years. Recently, digital waveform technology has begun to emerge and promises to supplant its older cousin because it presents new capabilities that result from the ability to instantaneously switch the frequency and duty cycle of the waveforms. This manuscript examines these capabilities and reveals their uses and effects on instrumentation...
October 2, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28956319/a-comparison-of-tissue-spray-and-lipid-extract-direct-injection-electrospray-ionization-mass-spectrometry-for-the-differentiation-of-eutopic-and-ectopic-endometrial-tissues
#18
Vitaliy Chagovets, Zhihao Wang, Alexey Kononikhin, Natalia Starodubtseva, Anna Borisova, Dinara Salimova, Igor Popov, Andrey Kozachenko, Konstantin Chingin, Huanwen Chen, Vladimir Frankevich, Leila Adamyan, Gennady Sukhikh
Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts...
September 27, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28956290/ion-mobility-spectrometry-mass-spectrometry-coupled-with-gas-phase-hydrogen-deuterium-exchange-for-metabolomics-analyses
#19
Hossein Maleki, Ahmad K Karanji, Sandra Majuta, Megan M Maurer, Stephen J Valentine
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...
September 27, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28956282/ir-ir-conformation-specific-spectroscopy-of-na-glucose-adducts
#20
Jonathan M Voss, Steven J Kregel, Kaitlyn C Fischer, Etienne Garand
We report an IR-IR double resonance study of the structural landscape present in the Na(+)(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na(+)(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers...
September 27, 2017: Journal of the American Society for Mass Spectrometry
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