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Journal of Mass Spectrometry: JMS

Natalia Gutowska, Piotr Seliger, Grzegorz Andrijewski, Grażyna Adamus, Iwona Kwiecień
The novel PNP-lariat ether L with cyclotriphosphazene ring incorporated in the macrocyclic structure was synthesized and checked by the ESI-MS method for the ability to bind different types of ions Ag+ , Ca2+ , Cd2+ , Cu2+ and Pb2+ . Furthermore, the stability constants of the abovementioned ions complexes with the investigated ligand have been determined by direct and competitive potentiometric methods. In order to evaluate the stability of various complexes types and to confirm the way of metal cation binding, the tandem mass spectra (MS/MS) of the investigated ligand and its complexes were taken...
January 19, 2018: Journal of Mass Spectrometry: JMS
Andrea Romano, George B Hanna
Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF-MS) is a direct injection MS technique, allowing for the sensitive and real-time detection, identification and quantification of volatile organic compounds (VOCs). When aiming to employ PTR-ToF-MS for targeted VOC analysis some methodological questions must be addressed, such as the need to correctly identify product ions, or evaluating the quantitation accuracy. This work proposes a workflow for PTR-ToF-MS method development, addressing the main issues affecting the reliable identification and quantification of target compounds...
January 16, 2018: Journal of Mass Spectrometry: JMS
Xiaoyan Cui, Can Sun, Pei Zhao, Yanyan Wang, Yanchun Guo, Yufen Zhao, Shuxia Cao
The fragmentation pathways of pentacoordinated phenoxyspirophosphoranes were investigated in the positive mode by electrospray ionization multistage mass spectrometry (ESI-MSn ). The results demonstrate that the sodium adducts of the title compounds undergo two competitive fragmentation pathways, and the fragmentation patterns are heavily dependent on the various substituent patterns at the phenolic group. An electron-withdrawing substituent at the ortho-position always results in the removal of a corresponding phenol analogue, while cleavage by spiroring opening becomes the predominant fragmentation pathway if an electron-donating substituent is at the phenolic group...
January 16, 2018: Journal of Mass Spectrometry: JMS
Thankan Jayasekharan, Shyam L Gupta, Vikas Dhiman
The intrinsic binding ability of seven natural peptides (oxytocin, arg8 -vasopressin, bradykinin, angiotensin-I, substance-P, somatostatin, and neurotensin) with copper in two different oxidation states (CuI/II ) derived from different Cu+/2+ precursor sources have been investigated for their charge dependent binding characteristics. The peptide-CuI/II complexes, [M - (n-1)H + nCuI ] and [M - (2n-1)H + nCuII ] are prepared/generated by the reaction of peptides with CuI solution/Cu-target and CuSO4 solution, and are analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)...
January 15, 2018: Journal of Mass Spectrometry: JMS
Bi-Cheng Yang, Xi-di Wan, Xiao Yang, Yun-Jun Li, Xiao-Ju Wan, Yong Luo, Wei Deng, Feng Wang, Ou-Ping Huang
The determination of pesticide residues is an indispensable task in controlling food safety and environment protection. Carbendazim is one of extensive use of pesticides in the agricultural industry. In this study, a simple method utilizing syringe filter has been applied as electrospray ionization emitter for mass spectrometric identification and quantification of carbendazim in complex matrices including soil, natural water, and fruit juice samples, which contain many insoluble materials. With online syringe filter of the complex samples, most of insoluble materials such as soil were excluded in spray ionization process due to the filter effect, and analytes were subsequently sprayed out from syringe needle for mass spectrometric detection...
January 4, 2018: Journal of Mass Spectrometry: JMS
Yali Wang, Lu Wang, Xiaolei Chen, Cuirong Sun, Yixin Zhu, Yu Kang, Su Zeng
In this study, a mass spectrometry (MS)-based kinetic method (KM) is shown to be successful at analyzing a multi-chiral center drug stereoisomer, entecavir (ETV), both qualitatively and quantitatively. On the basis of the KM, the bivalent complex ion [MII (A)(ref*)2 ]2+ (MII =divalent metal ion, A=analyte, ref*=chiral reference) was set as precursor ion in MS/MS. The experiment results suggest strong chiral selectivity between ETV and its isomers when using ZnII coordinated with the chiral reference R-besivance (R-B)...
January 4, 2018: Journal of Mass Spectrometry: JMS
Tibor Nagy, Ákos Kuki, Lajos Nagy, Miklós Zsuga, Sándor Kéki
Direct analysis in real time mass spectrometry (DART-MS) with in situ silylation was used for the rapid analysis of the flavonoids silybin ((2R,3R)-3,5,7-trihydroxy-2-[3-(4-hydroxy-3-methoxyphenyl)-2-hydroxymethyl-2,3-dihydrobenzo[1,4]dioxin-6-yl]chroman-4-one) and rutin (quercetin-3-O-rutinoside). Three different derivatization reagents, hexamethyldisilazane/trimethylchlorosilane/pyridine (HMDS/TMCS/pyridine), N,O-bis(trimethylsilyl)acetamide/trimethylchlorosilane/N-trimethylsilyimidazole (BSA/TMCS/TMSI) and N,O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/TMCS), were applied...
December 29, 2017: Journal of Mass Spectrometry: JMS
Marko Haramija
Hardware ion scan functions unique to MS/MS mode of data acquisition, such as precursor ion scan (PIS) and neutral loss scan (NLS) are important for selective extraction of key structural data from complex MS/MS spectra. However, their software counterparts, software ion scan (SIS) functions, are still not regularly available. SIS functions can be easily coded for additional functionalities, such as software multiple precursor ion scan (sMPIS), software no ion scan (sNIS) and software variable ion scan (sVIS) functions...
December 29, 2017: Journal of Mass Spectrometry: JMS
Estela de O Lima, Tatiane M Guerreiro, Carlos Fernando O R Melo, Diogo N de Oliveira, Daisy Machado, Marcelo Lancelloti, Rodrigo R Catharino
Recently, microcephaly cases have increased in Americas and have been matter of concern due to Zika virus (ZIKV) recent outbreak. Previous studies have shown that ZIKV-infected progenitor neuronal cells present morphological abnormalities and increased rates of cell death, which may be indicators of microcephaly causes. As recent studies indicate Zika virus' tropism for brain cells, how would a glioblastoma (GBM) lineage behave under ZIKV infection, considering GBM the most common and malignant brain tumor in adults, presenting extreme chemoresistance and high morbidity and mortality rates? The current trend of using genetically engineered oncolytic pathogens as a safe way to eliminate tumors is under development, with trials already in course...
December 28, 2017: Journal of Mass Spectrometry: JMS
Simone Colombo, Giulia Coliva, Agnieszka Kraj, Jean-Pierre Chervet, Maria Fedorova, Pedro Domingues, M Rosário Domingues
Phosphatidylethanolamines (PEs) are widely present in cellular membranes and lipoproteins. Oxidation of PEs fatty acyl chains generates several oxidized products, exerting a vast number of biological functions, not totally unveiled yet. In vitro biomimetic models have been used to identify oxidized PEs and to develop analytical strategies for their targeted detection in vivo. Most of the models are based on oxidation by reactive oxygen species (ROS), but the oxidative metabolism of PE also relies on controlled reactions catalyzed by enzymes as lipoxygenase (LOX), which can be mimicked by electrochemical (EC) oxidation...
December 28, 2017: Journal of Mass Spectrometry: JMS
Meng Miao, Gaosheng Zhao, Li Xu, Junguo Dong, Ping Cheng
A direct analytical method based on spray-inlet microwave plasma torch tandem mass spectrometry (MPT-MS/MS) was applied to simultaneously determine four phthalate esters (PAEs) including benzyl butyl phthalate (BBP), diethyl phthalate (DEP), dipentyl phthalate (DPP), and dodecyl phthalate (DIDP) with extremely high sensitivity in spirits without sample treatment. Among the four brands of spirit products, three kinds of PAE compounds were directly determined at very low concentrations from 1.30 to 114 ng g-1 ...
December 26, 2017: Journal of Mass Spectrometry: JMS
Clotilde Le Vot, Joël Lemaire, Pascal Pernot, Michel Heninger, Hélène Mestdagh, Essyllt Louarn
The reactivity of a series of commonly used halogenated compounds (trihalomethanes, chlorofluorocarbon, hydrochlorofluorocarbon, fluorocarbons and hydrofluoroolefin) with hydroxide and oxygen anion is studied in a compact FT-ICR. O- is formed by dissociative electron attachment to N2 O and HO- by a further ion-molecule reaction with ammonia. Kinetic experiments are performed by increasing duration of introduction of the studied molecule at a constant pressure. Hydroxide anion reactions mainly proceed by proton transfer for all the acidic compounds...
December 21, 2017: Journal of Mass Spectrometry: JMS
Herbert J Dias, Mariana V B Bento, Éder H da Silva, Andrade S Júnior, Marcelo F de Oliveira, Ricardo Vessecchi, Renato L T Parreira, Antônio E M Crotti
We have used a combination of multiple stage mass spectrometry (MSn ) experiments, hydrogen/deuterium exchange experiments, and thermochemical data estimated by computational chemistry calculations at the B3LYP/6-31+G(d,p) level of theory to revisit the gas-phase fragmentation of protonated cocaine. The lone pair of nitrogen participates in major fragmentation routes of protonated cocaine, to generate cyclic iminium ions. The structure of product ion m/z 182, which has been previously proposed in the literature, was shown to be unstable; therefore, we have decided to revisit it...
December 16, 2017: Journal of Mass Spectrometry: JMS
Eelco N Pieke, Jørn Smedsgaard, Kit Granby
In fields such as food safety and environmental chemistry, ensuring safety is greatly challenged by large numbers of unknown substances occurring. Even with current state of the art mass spectrometers, dealing with non-identified substances is a very laborious process as it includes structure elucidation of a vast number of unknowns, of which only a fraction may be relevant. Here, we present an exploration and prioritization approach based on high resolution mass spectrometry. The method uses algorithm-based precursor/product-ion correlations on Quadrupole-Time of Flight (Q-TOF) MS/MS data to retrieve the most likely chemical match from a structure database...
December 8, 2017: Journal of Mass Spectrometry: JMS
Carl Fletcher, Richard Sleeman, John Luke, Peter Luke, James W Bradley
The detection of explosives is of great importance, as is the need for sensitive, reliable techniques that require little or no sample preparation and short run times for high throughput analysis. In this work, a novel ionisation source is presented based on a dielectric barrier discharge (DBD). This not only effects desorption and ionisation, but also forms an ionic wind, providing mass transportation of ions towards the mass spectrometer. Furthermore, the design incorporates two asymmetric alumina sheets, each containing three DBDs, so that a large surface area can be analysed...
December 6, 2017: Journal of Mass Spectrometry: JMS
P R Dos Santos, C M P Pereira, M Ritter, F R de Paula, S Moura
Over the years, with the instrumental analyzes evolution, the relationships between the carried-out results with the data of theoretical analysis in silico and the Hammett's parameters have been reported. They have been very useful for chemical characterization of small organic molecules. Thus, this work aims at showing the feasibility and limitations for Hammett's and Density Functional Theory (DFT) applications in ESI-CID fragmentation provision. For this, thirteen dihydropyrimidinones (DHPM's) para, meta and orto monosubstituted were studied using Electrospray Ionization (ESI) and Collision-Induced Dissociation (CID) in positive mode...
November 30, 2017: Journal of Mass Spectrometry: JMS
Joerg Doellinger, Marica Grossegesse, Andreas Nitsche, Peter Lasch
Large-scale detection of ubiquitination sites in whole cell proteomes using nanoLC-MS/MS is a well-established technique that has deepened the understanding of protein degradation processes in eukaryotic cells. Ubiquitination sites are usually identified by detection of Lys-ɛ-Gly-Gly (K-ɛ-GG)-remnant peptides, which are generated by tryptic digestion of proteomes. We show in this application note that DMSO addition to the LC mobile-phase enhances identification rates of K-ɛ-GG peptides by more than 100 % due to an increase of peptide signal intensities...
November 29, 2017: Journal of Mass Spectrometry: JMS
Yunchen Le, Xiaoyan Shen, Hongyan Kang, Qizheng Wang, Kejia Li, Jie Zheng, Yunqiu Yu
Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of skin-homing T-cell neoplasms. Clinical management is stage based but diagnosis and prognosis could be extremely challenging. The presented study aims to explore the metabolic profiling of CTCL by an accelerated untargeted metabolomics data analysis tool "mummichog" to facilitate the discoveries of potential biomarkers for clinical early-stage diagnosis, prognosis and treatments in CTCL. Ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) based untargeted metabolomics were conducted on the skin and plasma of CTCL mice...
November 21, 2017: Journal of Mass Spectrometry: JMS
Aleš Marek, Huong T H Nguyen, Břetislav Brož, František Tureček
We report non-chiral amino acid residues cis- and trans-1,4-diaminocyclohexane-1-carboxylic acid (cyclo-ornithine, cO) that exhibit unprecedented stereospecific control of backbone dissociations of singly charged peptide cations and hydrogen-rich cation radicals produced by electron-transfer dissociation (ETD). Upon collision-induced dissociation (CID) in the slow heating regime, peptide cations containing trans-cO residues undergo facile backbone cleavages of amide bonds C-terminal to trans-cO. In contrast, peptides with cis-cO residues undergo dissociations at several amide bonds along the peptide ion backbone...
November 18, 2017: Journal of Mass Spectrometry: JMS
Viktor Sándor, Anikó Kilár, Ferenc Kilár, Béla Kocsis, Ágnes Dörnyei
In this study, we report the detailed analysis of the fragmentation patterns of positively charged lipid A species based on their tandem mass spectra obtained under low-energy collision-induced dissociation conditions of an electrospray quadrupole time-of-flight mass spectrometers. The tandem mass spectrometry experiments were performed after the separation of the compounds with a reversed-phase high performance liquid chromatography method. We found that both, phosphorylated and nonphosphorylated lipid A molecules can be readily ionized in the positive-ion mode by adduct formation with triethylamine added to the eluent...
November 16, 2017: Journal of Mass Spectrometry: JMS
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