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Journal of the American Society for Mass Spectrometry

Thomas Powell, Steve Bowra, Helen J Cooper
Previously we have shown that subcritical water may be used as an alternative to enzymatic digestion in the proteolysis of proteins for bottom-up proteomics. Subcritical water hydrolysis of proteins was shown to result in protein sequence coverages greater than or equal to that obtained following digestion with trypsin; however, the percentage of peptide spectral matches for the samples treated with trypsin were consistently greater than for those treated with subcritical water. This observation suggests that in addition to cleavage of the peptide bond, subcritical water treatment results in other hydrolysis products, possibly due to modifications of amino acid side chains...
May 17, 2017: Journal of the American Society for Mass Spectrometry
Hong Zhang, Na Li, Dandan Zhao, Jie Jiang, Hong You
Real-time monitoring of photocatalytic reactions facilitates the elucidation of the mechanisms of the reactions. However, suitable tools for real-time monitoring are lacking. Herein, a novel method based on droplet spray ionization named substrate-coated illumination droplet spray ionization (SCI-DSI) for direct analysis of photocatalytic reaction solution is reported. SCI-DSI addresses many of the analytical limitations of electrospray ionization (ESI) for analysis of photocatalytic-reaction intermediates, and has potential for both in situ analysis and real-time monitoring of photocatalytic reactions...
May 17, 2017: Journal of the American Society for Mass Spectrometry
Shin Hye Kim, Jeongkwon Kim, Young Jin Lee, Tae Geol Lee, Sohee Yoon
Corn seed tissue sections were prepared by the tape support method using an adhesive tape, and mass spectrometry imaging (MSI) was performed. The effect of heat generated during sample preparation was investigated by time-of-flight secondary mass spectrometry (TOF-SIMS) imaging of corn seed tissue prepared by the tape support and the thaw-mounted methods. Unlike thaw-mounted sample preparation, the tape support method does not cause imaging distortion because of the absence of heat, which can cause migration of the analytes on the sample...
May 15, 2017: Journal of the American Society for Mass Spectrometry
Sy-Chyi Cheng, Suhail Muzaffar Bhat, Jentaie Shiea
Flame atmospheric pressure chemical ionization (FAPCI) combined with negative electrospray ionization (ESI) mass spectrometry was developed to detect the ion/molecule reactions (IMRs) products between nitric acid (HNO3) and negatively charged amino acid, angiotensin I (AI) and angiotensin II (AII), and insulin ions. Nitrate and HNO3-nitrate ions were detected in the oxyacetylene flame, suggesting that a large quantity of nitric acid (HNO3) was produced in the flame. The HNO3 and negatively charged analyte ions produced by a negative ESI source were delivered into each arm of a Y-shaped stainless steel tube where they merged and reacted...
May 15, 2017: Journal of the American Society for Mass Spectrometry
Rahel P Eberle, Yvonne Hari, Stefan Schürch
Bent metallocenes Cp2MCl2 (M = Ti, V, Nb, Mo) are known to exhibit cytotoxic activity against a variety of cancer types. Though the mechanism of action is not fully understood yet, the accumulation of the metal ions in the nucleus points towards DNA as one of the primary targets. A set of eight deoxydinucleoside monophosphates was used to study the adduct yields with metallocenes and cisplatin. The binding affinities are reflected by the relative intensities of the adducts and were found to follow the order of Pt > V > Ti > Mo (no adducts were detected with Nb)...
May 12, 2017: Journal of the American Society for Mass Spectrometry
Tiffany M Jarrell, Benjamin C Owen, James S Riedeman, Boone M Prentice, Chris J Pulliam, Joann Max, Hilkka I Kenttämaa
Laser-induced acoustic desorption (LIAD) allows for desorption of neutral nonvolatile compounds independent of their volatility or thermal stability. Many different ionization methods have been coupled with LIAD. Hence, this setup provides a better control over the types of ions formed than other mass spectrometry evaporation/ionization methods commonly used to characterize biomolecules, such as ESI or MALDI. In this study, the utility of LIAD coupled with electron ionization (EI) was tested for the analysis of common amino acids with no derivatization...
May 12, 2017: Journal of the American Society for Mass Spectrometry
John E Carpenter, Christopher P McNary, April Furin, Andrew F Sweeney, P B Armentrout
The first absolute experimental bond dissociation energies (BDEs) for the main heterolytic bond cleavages of four benzylpyridinium "thermometer" ions are measured using threshold collision-induced dissociation in a guided ion beam tandem mass spectrometer. In this experiment, substituted benzylpyridinium ions are introduced into the apparatus using an electrospray ionization source, thermalized, and collided with Xe at varied kinetic energies to determine absolute cross-sections for these reactions. Various effects are accounted for, including kinetic shifts, multiple collisions, and internal and kinetic energy distributions...
May 12, 2017: Journal of the American Society for Mass Spectrometry
Dwight E Matthews
May 12, 2017: Journal of the American Society for Mass Spectrometry
R R Wu, L A Hamlow, C C He, Y-W Nei, G Berden, J Oomens, M T Rodgers
The gas-phase conformations of the protonated forms of the DNA and RNA cytosine mononucleotides, [pdCyd+H](+) and [pCyd+H](+), are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy over the IR fingerprint and hydrogen-stretching regions complemented by electronic structure calculations. The low-energy conformations of [pdCyd+H](+) and [pCyd+H](+) and their relative stabilities are computed at the B3LYP/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) and MP2(full)/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) levels of theory...
May 11, 2017: Journal of the American Society for Mass Spectrometry
Zhou Peng, Jiexun Bu, Scott A McLuckey
We examine a gas-phase approach for converting a subset of amino acid residues in polypeptide cations to dehydroalanine (Dha). Subsequent activation of the modified polypeptide ions gives rise to specific cleavage N-terminal to the Dha residue. This process allows for the incorporation of selective cleavages in the structural characterization of polypeptide ions. An ion/ion reaction within the mass spectrometer between a multiply protonated polypeptide and the sulfate radical anion introduces a radical site into the multiply protonated polypeptide reactant...
May 11, 2017: Journal of the American Society for Mass Spectrometry
Rebecca L Hansen, Young Jin Lee
Metabolomics experiments require chemical identifications, often through MS/MS analysis. In mass spectrometry imaging (MSI), this necessitates running several serial tissue sections or using a multiplex data acquisition method. We have previously developed a multiplex MSI method to obtain MS and MS/MS data in a single experiment to acquire more chemical information in less data acquisition time. In this method, each raster step is composed of several spiral steps and each spiral step is used for a separate scan event (e...
May 10, 2017: Journal of the American Society for Mass Spectrometry
Thamina Acter, Donghwi Kim, Arif Ahmed, Ji-Hyoung Ha, Sunghwan Kim
Herein we report the observation of atmospheric pressure in-source hydrogen-deuterium exchange (HDX) of thiol group for the first time. The HDX for thiol group was optimized for positive atmospheric pressure photoionization (APPI) mass spectrometry (MS). The optimized HDX-MS was applied for 31 model compounds (thiols, thiophenes, and sulfides) to demonstrate that exchanged peaks were observed only for thiols. The optimized method has been successfully applied to the isolated fractions of sulfur-rich oil samples...
May 9, 2017: Journal of the American Society for Mass Spectrometry
Paul W A Devine, Henry C Fisher, Antonio N Calabrese, Fiona Whelan, Daniel R Higazi, Jennifer R Potts, David C Lowe, Sheena E Radford, Alison E Ashcroft
Collision cross-section (CCS) measurements obtained from ion mobility spectrometry-mass spectrometry (IMS-MS) analyses often provide useful information concerning a protein's size and shape and can be complemented by modeling procedures. However, there have been some concerns about the extent to which certain proteins maintain a native-like conformation during the gas-phase analysis, especially proteins with dynamic or extended regions. Here we have measured the CCSs of a range of biomolecules including non-globular proteins and RNAs of different sequence, size, and stability...
May 8, 2017: Journal of the American Society for Mass Spectrometry
Shane R Ellis, Huong T Pham, Marc In Het Panhuis, Adam J Trevitt, Todd W Mitchell, Stephen J Blanksby
Reaction products from the ozonolysis of unsaturated lipids at gas-liquid interfaces have the potential to significantly influence the chemical and physical properties of organic aerosols in the atmosphere. In this study, the gas-phase dissociation behavior of lipid secondary ozonides is investigated using ion-trap mass spectrometry. Secondary ozonides were formed by reaction between a thin film of unsaturated lipids (fatty acid methyl esters or phospholipids) with ozone before being transferred to the gas phase as [M + Na](+) ions by electrospray ionization...
May 8, 2017: Journal of the American Society for Mass Spectrometry
Victoria Silva Amador, Hebert Vinicius Pereira, Marcelo Martins Sena, Rodinei Augusti, Evandro Piccin
This article describes the use of paper spray mass spectrometry (PS-MS) for the direct analysis of black ink writings made with ballpoint pens. The novel approach was developed in a forensic context by first performing the classification of commercially available ballpoint pens according to their brands. Six of the most commonly worldwide utilized brands (Bic, Paper Mate, Faber Castell, Pentel, Compactor, and Pilot) were differentiated according to their characteristic chemical patterns obtained by PS-MS. MS on the negative ion mode at a mass range of m/z 100-1000 allowed prompt discrimination just by visual inspection...
May 5, 2017: Journal of the American Society for Mass Spectrometry
Vaibhav Shrivastav, Minal Nahin, Christopher J Hogan, Carlos Larriba-Andaluz
A benchmark comparison between two ion mobility and collision cross-section (CCS) calculators, MOBCAL and IMoS, is presented here as a standard to test the efficiency and performance of both programs. Utilizing 47 organic ions, results are in excellent agreement between IMoS and MOBCAL in He and N2, when both programs use identical input parameters. Due to a more efficiently written algorithm and to its parallelization, IMoS is able to calculate the same CCS (within 1%) with a speed around two orders of magnitude faster than its MOBCAL counterpart when seven cores are used...
May 5, 2017: Journal of the American Society for Mass Spectrometry
Sandra Osburn, Gaetano Speciale, Spencer J Williams, Richard A J O'Hair
A suite of isotopologues of methyl D-glucopyranosides is used in conjunction with multistage mass spectrometry experiments to determine the radical site and cleavage reactions of sugar radical cations formed via a recently developed 'bio-inspired' method. In the first stage of CID (MS(2)), collision-induced dissociation (CID) of a protonated noncovalent complex between the sugar and S-nitrosocysteamine, [H3NCH2CH2SNO + M](+), unleashes a thiyl radical via bond homolysis to give the noncovalent radical cation, [H3NCH2CH2S(•) + M](+)...
May 4, 2017: Journal of the American Society for Mass Spectrometry
Xiuting Chen, Qingnuan Li, Yu Gong
Electrospray ionization (ESI) of LnCl3 (Ln = La-Lu except Pm) and TMGA (tetramethyl glutaramide) mixtures resulted in the formation of gas-phase Ln(TMGA)3(3+) complexes, where tripositive lanthanide cation was coordinated by three neutral TMGA ligands. Collision induced dissociation (CID) was employed to investigate the fragmentation chemistry of these tripositive complexes. Ln(TMGA)2(TMGA- 45)(3+) resulting from Ccarbonyl-N bond cleavage of TMGA and hydrogen transfer is the major CID product for all Ln(TMGA)3(3+) except Eu(TMGA)3(3+) which predominantly forms divalent Eu(II)(TMGA)2(2+) complex via loss of TMGA(+)...
May 2, 2017: Journal of the American Society for Mass Spectrometry
Cosima Damiana Calvano, Tommaso R I Cataldi, Julius F Kögel, Antonio Monopoli, Francesco Palmisano, Jorge Sundermeyer
The superbasic proton sponge 1,8-bis(tripyrrolidinylphosphazenyl)naphthalene (TPPN) has been successfully employed for the structural characterization of neutral saccharides, cyclodextrins, and saccharide alditols by matrix assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). Owing to its inherently high basicity, TPPN is capable of deprotonating neutral carbohydrates (M) providing an efficient and simple way to produce gas-phase [M - H](-) ions. Highly informative negative ions MS/MS spectra showing several diagnostic fragment ions were obtained, mainly A-type cross-ring and C-type glycosidic cleavages...
May 2, 2017: Journal of the American Society for Mass Spectrometry
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