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Journal of the American Society for Mass Spectrometry

Cameron S Movassaghi, Declan P McCarthy, Deepak Bhandari, Benjamin C Blount, Víctor R De Jesús
Multiple ion transition summation of isotopologues (MITSI) is an adaptable and easy-to-implement methodology for improving analytical sensitivity, especially for halogenated compounds and otherwise abundant isotopologues. This novel application of signal summing was applied to measure and quantitate the two most abundant ion transitions of two isotopologues of N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine (1DCV), a urinary metabolite of trichloroethylene (TCE). Because 1DCV is dichlorinated, only approximately half of the total potential signal is quantifiable when the monoisotopic ion transition (i...
April 22, 2019: Journal of the American Society for Mass Spectrometry
Edward D Hoegg, Simon Godin, Joanna Szpunar, Ryszard Lobinski, David W Koppenaal, R Kenneth Marcus
Many fundamental questions of astrophysics, biochemistry, and geology rely on the ability to accurately and precisely measure the mass and abundance of isotopes. Taken a step further, the capacity to perform such measurements on intact molecules provides insights into processes in diverse biological systems. Described here is the coupling of a combined atomic and molecular (CAM) ionization source, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma, with a commercially available ThermoScientific Fusion Lumos mass spectrometer...
April 18, 2019: Journal of the American Society for Mass Spectrometry
Xi Chen, Shannon A Raab, Timothy Poe, David E Clemmer, Carlos Larriba-Andaluz
The strong synergy arising from coupling two orthogonal analytical techniques such as ion mobility and mass spectrometry can be used to separate complex mixtures and determine structural information of analytes in the gas phase. A tandem study is performed using two systems with different gases and pressures to ascertain gas-phase conformations of homopolymer ions. Aside from spherical and stretched configurations, intermediate configurations formed by a multiply charged globule and a "bead-on-a-string" appendix are confirmed for polyethylene-glycol (PEG), polycaprolactone (PCL), and polydimethylsiloxane (PDMS)...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Jessica L Cleary, Gordon T Luu, Emily C Pierce, Rachel J Dutton, Laura M Sanchez
Multispecies microbiome systems are known to be closely linked to human, animal, and plant life processes. The growing field of metabolomics presents the opportunity to detect changes in overall metabolomic profiles of microbial species interactions. These metabolomic changes provide insight into function of metabolites as they correlate to different species presence and the observed phenotypic changes, but detection of subtle changes is often difficult in samples with complex backgrounds. Natural environments such as soil and food contain many molecules that convolute mass spectrometry-based analyses, and identification of microbial metabolites amongst environmental metabolites is an informatics problem we begin to address here...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Andrew R Johnson, Erin E Carlson
The 14- and 16-membered macrolide antibiotics are an important structural class. Ubiquitously produced by a number of bacterial strains, namely actinomycetes, purification and structure elucidation of the wide array of analogs is challenging, both for discovery efforts and methodologies to monitor for byproducts, metabolites, and contaminants. Collision-induced dissociation mass spectrometry offers an attractive solution, enabling characterization of mixtures, and providing a wealth of structural information...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Chuping Lee, Chi-Kung Ni
Since its introduction, matrix-assisted laser desorption/ionization (MALDI) has been widely used for the mass analysis of biomolecules. The "soft ionization" of MALDI enables accurate mass determination of intact biomolecules. However, the ionization and desorption processes of MALDI are not adequately soft as many labile biomolecules, such as glycoconjugates containing sialic acid or the sulfate functional group, easily dissociate into fragments and sometimes, no intact molecules are observed. In this study, we compared the conventional matrix of MALDI, namely 2,5-dihydroxybenzoic acid, to various soft matrices of MALDI-specifically, 5-methoxysalicylic acid, diamond nanoparticle trilayers, HgTe nanostructures, ionic liquid, and droplets of frozen solutions-by using three labile glycoconjugates as analytes: gangliosides, heparin, and pullulan...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Benjamin E Draper, Martin F Jarrold
Charge detection mass spectrometry (CDMS) is an important tool for measuring mass distributions for high mass samples and heterogeneous mixtures. In CDMS, single ions are trapped and their m/z and charge are measured simultaneously. As a single particle technique, the average signal must be optimized to maximize the number of single ion trapping events. If the average signal is too small, most of the trapping events will be empty, and if the average signal is too large, most of the trapping events will contain multiple ions...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Ben Nie, Jack Henion, Imelda Ryona
The focus of this critical insight article is a brief overview of analytical challenges the cannabis industry faces and how analytical chemists have new opportunities to demonstrate the merits of employing mass spectrometry for the chemical analysis of cannabis and its products. The current range of cannabis products extends from recreational use to medicines, edibles, beverages, and beyond. The standards employed to assure product quality, integrity, and safety are lacking compared to those currently used by the pharmaceutical, food, and beverage industries...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Tianjiao Huang, Jordan M Rabus, Benjamin J Bythell, James L Edwards
We demonstrate increasing the charge state of small molecules using derivatized lysine as our model system. Lysine is chemically tagged with three tertiary amines which enables efficient production of highly charged analytes. A +3 charge state is obtained from direct infusion nanoelectrospray conditions. Collisional activation of the +3 derivatized lysine yielded structurally informative product ions corresponding to cleavages across the analyte backbone and within the proton affinity tags. This suggests a role for multi-charging of metabolites in both targeted MRM analyses and untargeted analyses to help identify novel metabolites...
April 16, 2019: Journal of the American Society for Mass Spectrometry
Kelsey A Morrison, Benjamin J Bythell, Brian H Clowers
Within trace vapor analysis in environmental monitoring, defense, and industry, atmospheric flow tube mass spectrometry (AFT-MS) can fill a role that incorporates non-contact vapor analysis with the selectivity and low detection limits of mass spectrometry. AFT-MS has been applied to quantitating certain explosives by selective clustering with nitrate and more recently applied to detecting tributyl phosphate and dimethyl methylphosphonate as protonated species. Developing AFT-MS methods for organophosphorus species is appealing, given that this class of compounds includes a range of pollutants, chemical warfare agent (CWA) simulants, and CWA degradation products...
April 15, 2019: Journal of the American Society for Mass Spectrometry
Tobias Reinecke, Austen L Davis, Brian H Clowers
In a standard single averaged, drift tube ion mobility spectrometry (IMS) experiment, typically less than 1% of the ions are utilized, with the rest of the ions neutralizing on a closed ion gate or ion optic element. Though some efforts at lower pressures (e.g., 4 Torr) have been made to address this issue by concentrating ions prior to release into a drift cell, the ion current reaching the detector during an IMS experiment is often diminished due to this lower duty cycle. Additionally, when considering the temporal nature of the drift tube IMS experiment and the trajectory of IMS towards higher resolution separations and lower duty cycles, increased detector sampling rates are another factor also which further necessitates new modes of conducting the IMS experiment...
April 15, 2019: Journal of the American Society for Mass Spectrometry
Sandra N Majuta, Chong Li, Kinkini Jayasundara, Ahmad Kiani Karanji, Kushani Attanayake, Nandhini Ranganathan, Peng Li, Stephen J Valentine
Rapid, solution-phase hydrogen/deuterium exchange (HDX) coupled with mass spectrometry (MS) is demonstrated as a means for distinguishing small-molecule metabolites. HDX is achieved using capillary vibrating sharp-edge spray ionization (cVSSI) to allow sufficient time for reagent mixing and exchange in micrometer-sized droplets. Different compounds are observed to incorporate deuterium with varying efficiencies resulting in unique isotopic patterns as revealed in the MS spectra. Using linear regression techniques, parameters representing contribution to exchange by different hydrogen types can be computed...
April 12, 2019: Journal of the American Society for Mass Spectrometry
Davide Corinti, Maria Elisa Crestoni, Simonetta Fornarini, Fortuna Ponte, Nino Russo, Emilia Sicilia, Elisabetta Gabano, Domenico Osella
Kinetically inert platinum(IV) complexes are receiving growing attention as promising candidates in the effort to develop safe and valid alternatives to classical square-planar Pt(II) complexes currently used in antineoplastic therapy. Their antiproliferative activity requires intracellular Pt(IV)-Pt(II) reduction (activation by reduction). In the present work, a set of five Pt(IV) complexes has been assayed using mass spectrometry-based techniques, i.e., collision-induced dissociation (CID), and IR multiple photon dissociation (IRMPD) spectroscopy, together with ab initio theoretical investigations...
April 12, 2019: Journal of the American Society for Mass Spectrometry
Christopher R Conant, Daniel R Fuller, Tarick J El-Baba, Zhichao Zhang, David H Russell, David E Clemmer
We report ion mobility spectrometry and mass spectrometry studies of the non-enzymatic step-by-step degradation of substance P (subP), an 11-residue neuropeptide, with the sequence Arg1 -Pro2 -Lys3 -Pro4 -Gln5 -Gln6 -Phe7 -Phe8 -Gly9 -Leu10 -Met11 -NH2 , in ethanol. At elevated solution temperatures (55 to 75 °C), several reactions are observed, including a protonation event, i.e., [subP+2H]2+ + H+  → [subP+3H]3+ , that appears to be regulated by a configurational change and two sequential bond cleavages (the Pro2 -Lys3 peptide bond is cleaved to form the smaller nonapeptide Lys3 -Met11 -NH2 [subP(3-11) ], and subsequently, subP(3-11) is cleaved at the Pro4 -Gln5 peptide bond to yield the heptapeptide Gln5 -Met11 -NH2 [subP(5-11) ])...
April 12, 2019: Journal of the American Society for Mass Spectrometry
Christopher R Conant, Daniel R Fuller, Zhichao Zhang, Daniel W Woodall, David H Russell, David E Clemmer
The work presented below is related to our companion paper in this issue, entitled: Substance P in solution: trans-to-cis configurational changes of penultimate prolines initiate non-enzymatic peptide bond cleavages. Two-dimensional ion mobility spectrometry (IMS-IMS) and mass spectrometry techniques are used to investigate structural transitions for [M+3H]3+ ions of substance P (subP) upon collisional activation (CA) in the gas phase. In this approach, different conformations of ions having a specified mobility are selected after an initial IMS separation, collisionally activated to produce new conformers, and these product structures are separated again using a second IMS region...
April 12, 2019: Journal of the American Society for Mass Spectrometry
Jakub Ujma, David Ropartz, Kevin Giles, Keith Richardson, David Langridge, Jason Wildgoose, Martin Green, Steven Pringle
There is increasing biopharmaceutical interest in oligosaccharides and glycosylation. A key requirement for these sample types is the ability to characterize the chain length, branching, type of monomers, and importantly stereochemistry and anomeric configuration. Herein, we showcase the multi-function capability of a cyclic ion mobility (cIM) separator embedded in a quadrupole/time-of-flight mass spectrometer (Q-ToF MS). The instrument design enables selective activation of mobility-separated precursors followed by cIM separation of product ions, an approach analogous to MSn ...
April 11, 2019: Journal of the American Society for Mass Spectrometry
Michael T Bowers, David H Russell, Veronica M Bierbaum
No abstract text is available yet for this article.
April 11, 2019: Journal of the American Society for Mass Spectrometry
Juan Fernandez de la Mora
We study the space charge limited maximal current density j″ of mobility-selected ions that can be transmitted in ion mobility spectrometry (IMS). Theory and experiments focus on differential mobility analyzers (DMAs), but are readily generalizable to other IMS devices. Repulsion between the ions in the cloud leads to beam spreading, with significant broadening once the ion number density n becomes comparable to the space charge saturation limit nsat  = εo Eo /(eΔ). Δ is the distance traversed by the ions in the direction of an externally imposed electric field Eo , and e is the charge on each ion...
April 9, 2019: Journal of the American Society for Mass Spectrometry
Rachele A Lubeckyj, Abdul Rehman Basharat, Xiaojing Shen, Xiaowen Liu, Liangliang Sun
Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has attracted attention recently for top-down proteomics because it can achieve highly efficient separation and very sensitive detection of proteins. However, separation window and sample loading volume of CZE need to be boosted for a better proteome coverage using CZE-MS/MS. Here, we present an improved CZE-MS/MS system that achieved a 180-min separation window and a 2-μL sample loading volume for top-down characterization of protein mixtures...
April 9, 2019: Journal of the American Society for Mass Spectrometry
Marius M Kostelic, Alex M Ryan, Deseree J Reid, Jibriel M Noun, Michael T Marty
Native mass spectrometry (MS) has become an important tool for the analysis of membrane proteins. Although detergent micelles are the most commonly used method for solubilizing membrane proteins for native MS, nanoscale lipoprotein complexes such as nanodiscs are emerging as a promising complementary approach because they solubilize membrane proteins in a lipid bilayer environment. However, prior native MS studies of intact nanodiscs have employed only a limited set of phospholipids that are similar in mass...
April 9, 2019: Journal of the American Society for Mass Spectrometry
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