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Journal of Mass Spectrometry: JMS

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https://www.readbyqxmd.com/read/29150896/stereospecific-control-of-peptide-gas-phase-ion-chemistry-with-cis-and-trans-cyclo-ornithine-residues
#1
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
https://www.readbyqxmd.com/read/29144587/characterization-of-complex-heterogeneous-lipid-a-samples-using-hplc-ms-ms-technique-iii-positive-ion-mode-tandem-mass-spectrometry-to-reveal-phosphorylation-and-acylation-patterns-of-lipid-a
#2
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
https://www.readbyqxmd.com/read/29134720/investigation-of-sarin-se-reactivity-against-human-plasma-proteins-using-liquid-chromatography-tandem-mass-spectrometry
#3
Hamid Saeidian, Seyed Esmaeil Hosseini, Ali Amoozadeh, Mohammad Taghi Naseri, Mehran Babri
Electron ionization mass spectrum of sarin(Se) was interpreted in compare of sarin MS spectrum. Inhibition of butyrylcholinesterase (BuChE) of human plasma by sarin and sarin(Se) was determined spectrophotometrically using modified Ellman's method. It appeared that after incubation with sarin and sarin(Se), cholinesterase inhibition were 93% and 83%, respectively. Sarin, sarin(Se) and sarin(Se)-d7 were spiked into a vial containing human plasma and albumin adduct metabolites were identified using liquid chromatography-tandem mass spectrometry LC-MS/MS...
November 13, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29111606/incubation-with-cu-ii-and-zn-ii-salts-enhances-maldi-tof-mass-spectra-of-amyloid-beta-and-%C3%AE-synuclein-toward-in-vivo-analysis
#4
Andrea R Kelley, Madeline E Colley, George Perry, Stephan B H Bach
Insoluble senile plaque aggregates are indicative of Alzheimer's disease (AD) pathology. A similar phenomenon occurs in Parkinson's disease (PD) with the build-up of Lewy bodies. The analysis of senile plaques, and other brain samples, from AD and PD patients by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has advantages but also presents obstacles due to the nature of the processes utilized in isolation procedures and storage. Salts, buffers, and detergents necessary in isolation of biological species may cause adducts and ion suppression that convolute the spectra obtained...
November 7, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29105888/simulation-of-the-simultaneous-dual-frequency-resonance-excitation-of-ions-in-a-linear-ion-trap
#5
Chongsheng Xu, Fuxing Xu, N V Konenkov, Chuan-Fan Ding
The process of ion resonance dipolar excitation in a linear ion trap by two ejection waveforms with close frequencies is studied. The physical mechanism of increasing the resolving power using the ion excitation is a nonlinearity of the electric RF fields caused by space charge. Using two resonance forces with two close frequencies leads to the completion of two excitation processes. In the case of the perfect quadrupole electric field, the ion motion equations are linear, and as a result, the respondent ion ensemble is also a linear and valid superposition principle...
November 6, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29087004/quaternary-ammonium-isobaric-tag-for-a-relative-and-absolute-quantification-of-peptides
#6
Bartosz Setner, Piotr Stefanowicz, Zbigniew Szewczuk
Isobaric labeling quantification of peptides has become a method of choice for mass spectrometry-based proteomics studies. However, despite of wide variety of commercially available isobaric tags, none of the currently available methods offers significant improvement of sensitivity of detection during MS experiment. Recently, many strategies were applied to increase the ionization efficiency of peptides involving chemical modifications introducing quaternary ammonium fixed charge. Here, we present a novel quaternary ammonium based isobaric tag for relative and absolute quantification of peptides (QAS-iTRAQ 2-plex)...
October 31, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29076604/mass-spectrometry-characterization-of-endophytic-bacterium-curtobacterium-sp-strain-er1-6-isolated-from-citrus-sinensis
#7
Francisca Diana da Silva Araújo, Daiene Souza Santos, Carolina Clepf Pagotto, Welington Luiz de Araújo, Marcos Nogueira Eberlin
The bacteria of the genus Curtobacterium are usually seen as plant pathogen, but some species have been identified as endophytes of different crops, and could as such present a potential for disease control and plant growth promotion. We have therefore applied the desorption electrospray ionization mass spectrometry imaging (DESI-MSI) in the direct analysis of living Curtobacterium sp. strain ER1/6 colonies to map the surface metabolites, and electrospray ionization tandem mass spectrometry (ESI-MS/MS) for characterization of these compounds...
October 27, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29076598/a-comprehensive-in-vitro-and-in-vivo-metabolism-study-of-hydroxysafflor-yellow-a
#8
Liang Wu, Yuping Tang, Chenxiao Shan, Chuan Chai, Zhu Zhou, Xuqin Shi, Ning Ding, Jiaying Wang, Liping Lin, Renxiang Tan
As the most important marker component in Carthamus tinctorius L., hydroxysafflor yellow A (HSYA) was widely used in the prevention and treatment of cardiovascular diseases, due to its effect of improving blood supply, suppressing oxidative stress, protecting against ischemia/reperfusion. In this paper, both an in vitro microsomal incubation and an in vivo animal experiment were conducted, along with a LC-Q-TOF/MS instrument and a three-step protocol, to further explore the metabolism of HSYA. As a result, a total of 10 metabolites were searched and tentatively identified in plasma, urine and feces after intravenous administration of HSYA to male rats, although no obvious bio-transformation was found in the simulated rat liver microsomal system...
October 27, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29076201/direct-determination-of-%C3%AE-44-42-ca-isotope-ratio-by-ion-chromatography-low-resolution-multicollector-icpms
#9
Jakub Karasinski, Ewa Bulska, Ludwik Halicz, Marcin Wojciechowski, Agnieszka Anna Krata
High precision on-line procedure for measurement of calcium isotopic ratio by coupling Ion Chromatography (IC) to Multicollector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) was developed. Calcium separation from the sample matrix was achieved on an IC column - IonPac CS16 ID 3 mm connected with CERS 500 2 mm suppressor and followed by MC-ICPMS calcium isotopic ratio determination. Dry plasma mode was used with Aridus II desolvation system. In order to sustained samples with high level of total dissolved salts (TDS) as well as account capacity of applied analytical column, the method has been optimized with regards to calcium isotope ratio measurements with low resolution mass spectrometry...
October 27, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29053889/optimization-of-mass-spectrometry-acquisition-parameters-for-determination-of-polycarbonate-additives-degradation-products-and-colorants-migrating-from-food-contact-materials-to-chocolate
#10
Chiara Bignardi, Antonella Cavazza, Carmen Laganà, Paola Salvadeo, Claudio Corradini
The interest towards the so-called "substances of emerging concerns", in particular referred to objects intended to come into contact with food is recently growing. Such substances can be found in traces in simulants and in food products put in contact with plastic materials. In this context, it is important to set up analytical systems characterized by high sensitivity, and to improve detection parameters to enhance signals. This work was aimed at optimizing a method based on UHPLC coupled to High Resolution Mass Spectrometry to quantify the most common plastic additives, and able to detect the presence of polymers degradation products and coloring agents migrating from plastic re-usable containers...
October 20, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29052291/development-of-an-isotopic-stream-index-connecting-physiographic-characteristics-of-montane-catchments
#11
Tsung-Ren Peng, Lun-Tao Tong, Tsang-Sen Liu, Wen-Jun Zhan, Li-Wei Chiang, Wan-Chung Lu, Chi-Tsun Chen
This study is to develop an isotopic catchment-effect index (CEI) connecting the physiographic characteristics of stream catchments. A CEI, describing the extent of difference in stable water isotopic compositions (δ values) between stream water and local precipitation at any given sampling site, can help in judging whether water resource management should be focused on upstream regions of streams or local hydrology issues. To establish the isotopic CEI, this study measured δ values of stream water and derived δ(18) O of local precipitation based on regional isotopic altitude gradient at montane catchments of various sizes...
October 19, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28981178/modified-proton-transfer-reaction-mass-spectrometry-ptr-ms-operating-conditions-for-in-vitro-and-in-vivo-analysis-of-wine-aroma
#12
Etienne Sémon, Gaëlle Arvisenet, Elisabeth Guichard, Jean-Luc Le Quéré
With proton transfer reaction-mass spectrometry standard operating conditions, analysis of alcoholic beverages is an analytical challenge. Ethanol reacts with the primary ion H3 O(+) leading to its depletion and to formation of ethanol-related ions and clusters, resulting in unstable ionization and in significant fragmentation of analytes. Different methods were proposed but generally resulted in lowering the sensitivity and/or complicating the mass spectra. The aim of the present study was to propose a simple, sensitive and reliable method with fragmentation as low as possible, linearity within a realistic range of volatile organic compounds concentrations, and applicability to in vivo dynamic aroma release (nosespace) studies of wines...
October 5, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28963745/fragmentation-of-organic-ions-bearing-fixed-multiple-charges-observed-in-maldi-ms
#13
Xianwen Lou, Bao Li, Bas F M de Waal, Jurgen Schill, Matthew B Baker, Ralf A A Bovee, Joost L J van Dongen, Lech-Gustav Milroy, E W Meijer
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) was used to analyze a series of synthetic organic ions bearing fixed multiple charges. Despite the multiple intrinsic charges, only singly charged ions were recorded in each case. In addition to the pseudo-molecular ions formed by counter-ion adduction, deprotonation and electron-capture, a number of fragment ions were also observed. Charge splitting by fragmentation was found to be a viable route for charge reduction leading to the formation of the observed singly charged fragment ions...
September 29, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28960805/a-systematic-tandem-mass-spectrometric-study-of-anion-attachment-for-improved-detection-and-acidity-evaluation-of-nitrogen-rich-energetic-compounds
#14
Gabriel Gaiffe, Maxime C Bridoux, Christine Costanza, Richard B Cole
The development of rapid, efficient and reliable detection methods for the characterization of energetic compounds is of high importance to security forces concerned with terrorist threats. Using a mass spectrometric approach, characteristic ions can be produced by attaching anions to analyte molecules in the negative ion mode of electrospray ionization mass spectrometry (ESI-MS). Under optimized conditions, formed anionic adducts can be detected with higher sensitivities as compared to the deprotonated molecules...
September 28, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28960779/quantitation-of-anthocyanins-in-elderberry-fruit-extracts-and-nutraceutical-formulations-with-paper-spray-ionization-mass-spectrometry
#15
Robert B Cody, Jun Tamura, Kevin M Downard
The ability to rapidly identify and quantitate, over a wide range of concentrations, anthocyanins in food and therapeutic products is important to ensuring their presence at medicinally-significant levels. Sensitive, yet mild, analysis conditions are required given their susceptibility to degradation and transformation. Paper spray ionization has been used to detect and quantify the levels of anthocyanin levels in extracts of fresh and dried elderberries, and elderberry stems, as well as three commercially available nutraceutical formulations...
September 27, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28940471/screening-of-exon-methylation-biomarkers-for-colorectal-cancer-via-lc-ms-ms-strategy
#16
Qionglin Huang, QinjinYang, Mingming Mo, Xiaoxia Ye, Junjie Zhang, Lijian Zhang, Bin Chen, Jian Li, Chun Cai
The identification of biomarkers would be benefit for the diagnosis and treatment of colorectal cancer in clinic. DNA methylation in specific genomic regions, which had shown strongly association with disease genotypes, was effective indicators to reveal the occurrence and development of cancers. To screen out the methylation biomarkers for colorectal cancer (CRC), genomic DNA was isolated from colorectal cancerous and corresponding cancer-adjacent tissues collected from 30 CRC patients and then bisulfite-converted...
September 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28929549/uplc-qtof-ms-e-based-diagnostic-product-ion-filtering-to-unveil-unstable-c6-c2-glucoside-conjugates-in-forsythia-suspensa
#17
Yong-Gang Xia, Jun Liang, Xin-Dong Guo, Hui-Min Sun, Hai-Xue Kuang
Forsythia suspensa contains C6 -C2 glucoside conjugates (CCGCs) that are chemically unstable, thereby hindering their isolation and purification. In the present study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF) was utilized to screen and identify unstable CCGCs in the fruits and leaves of F. suspensa without any tedious isolation and purified process based on independent information acquisition (also called MS(E) ) and individual MS/MS experiments. Diagnostic product ion filtering (DPIF) was further applied to mine unknown analogs in MS(E) high energy levels based on characteristic m/z of key substructures...
September 20, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28929601/conversion-of-benzoic-acid-into-phenol-in-an-itms-under-ci-ms-n-conditions-recognition-of-ortho-chlorobenzoyl-derivatives
#18
Michela Begala
Isomeric chlorobenzoyl cations (m/z 139), under collision induced experiments, fragment identically. Chlorobenzoyl cations can be efficiently converted into cholorophenol radical cations by the reaction with methanol in the ion trap analyser under CI-MS(n) conditions. The substitution of the carbonyl group with a hydroxyl moiety is able to induce an ortho effect, which is absent in the starting ortho-chlorobenzoyl cation. This transformation could be useful to recognize ortho-chlorinated benzoyl derivatives without the need of MS spectra comparison of the whole set of isomers...
September 19, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28892241/seasonal-variations-in-the-profile-of-main-phospholipids-in-mytilus-galloprovincialis-mussels-a-study-by-hydrophilic-interaction-liquid-chromatography-electrospray-ionization-fourier-transform-mass-spectrometry
#19
Laura Facchini, Ilario Losito, Tommaso R I Cataldi, Francesco Palmisano
A systematic characterization of phosphatidylcholines (PC) and phosphatidylethanolamines (PE) in mussels of sp. Mytilus galloprovincialis was performed by high efficiency Hydrophilic Interaction LIquid Chromatography (HILIC) combined with ElectroSpray Ionization (ESI) and Fourier-Transform Mass Spectrometry (FTMS), based on a quadrupole-Orbitrap hybrid spectrometer. FTMS/MS experiments under high-collisional energy dissociation (HCD) conditions, complemented by low energy collisionally induced dissociation (CID) MS(n) (n = 2,3) experiments, performed in a linear ion trap mass spectrometer, were exploited for structural elucidation purposes...
September 11, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28885753/study-of-gas-phase-reactions-of-no2-with-aromatic-compounds-using-proton-transfer-reaction-time-of-flight-mass-spectrometry
#20
Jianquan Li, Xubing Du, Teng Guo, Zhen Peng, Li Xu, Junguo Dong, Ping Cheng, Zhen Zhou
The study of ion chemistry involving the NO2(+) is currently the focus of considerable fundamental interest and is relevant in diverse fields ranging from mechanistic organic chemistry to atmospheric chemistry. A very intense source of NO2(+) was generated by injecting the products from the dielectric barrier discharge (DBD) of a nitrogen and oxygen mixture upstream into the drift tube of a proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) apparatus with H3 O(+) as the reagent ion. The NO2(+) intensity is controllable and related to the DBD operation conditions and ratio of oxygen to nitrogen...
September 8, 2017: Journal of Mass Spectrometry: JMS
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