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Journal of Mass Spectrometry: JMS

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https://www.readbyqxmd.com/read/28171689/collision-induced-dissociation-processes-of-protonated-benzoic-acid-and-related-compounds-competitive-generation-of-protonated-carbon-dioxide-or-protonated-benzene
#1
Sihang Xu, Julius Pavlov, Athula B Attygalle
Upon activation in the gas phase, protonated benzoic acid (m/z 123) undergoes fragmentation by several mechanisms. In addition to the predictable water loss followed by a CO loss, the m/z 123 ion more intriguingly eliminates a molecule of benzene to generate protonated carbon dioxide (HO(+) C≡O, m/z 45), or a molecule of carbon dioxide to yield protonated benzene (m/z 79). Experimental evidence shows that the incipient proton ambulates during the fragmentation processes. For the CO2 or benzene loss, protonated benzoic acid transfers the charge-imparting proton initially to the ortho position and then to the ipso position to generate a transient species which dissociates to form an ion-neutral complex between benzene and protonated CO2 ...
February 7, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28170125/effects-of-acidic-peptide-size-and-sequence-on-trivalent-praseodymium-adduction-and-electron-transfer-dissociation-mass-spectrometry
#2
Juliette J Commodore, Carolyn J Cassady
Using the lanthanide ion praseodymium, Pr(III), metallated ion formation and electron transfer dissociation (ETD) were studied for 25 biological and model acidic peptides. For chain lengths of seven or more residues, even highly acidic peptides that can be difficult to protonate by electrospray ionization will metallate and undergo abundant ETD fragmentation. Peptides composed of predominantly acidic residues form only the deprotonated ion, [M + Pr - H](2+) ; this ion yields near complete ETD sequence coverage for larger peptides...
February 7, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28152561/evaluation-of-relative-ms-response-factors-of-drug-metabolites-for-semi-quantitative-assessment-of-chemical-liabilities-in-drug-discovery
#3
Joachim Blanz, Gareth Williams, Jerôme Dayer, Thierry Délémonté, Werner Gertsch, Philippe Ramstein, Reiner Aichholz, Markus Trunzer, David Pearson
Drug metabolism studies are performed in drug discovery to identify metabolic soft spots, detect potentially toxic or reactive metabolites and provide an early insight into potential species differences. The relative peak area approach is often used to semi-quantitatively estimate the abundance of metabolites. Differences in the LC/MS responses result in an under- or overestimation of the metabolite and misinterpretation of results. The relative MS response factors of 132 structurally diverse drug candidates and their 233 corresponding metabolites were evaluated using a capillary-LC/HRMS system...
February 2, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28152260/thermal-dissociation-of-ions-limits-the-degree-of-the-gas-phase-h-d-exchange-at-the-atmospheric-pressure
#4
Yury Kostyukevich, Alexey Kononikhin, Igor Popov, Eugene Nikolaev
We present the application of the extended desolvating capillaries for the increasing the degree of the gas-phase H/D exchange reaction at atmospheric pressure. The use of the extended capillaries results in the increase of the time that ions spends in the high pressure region, what leads to the significant improvement of the efficiency of the reaction. For the small protein ubiquitin it was observed, that for the same temperature, number of exchanges increases with the decrease of the charge state so that the lowest charge state can exchange twice the number of hydrogen than the highest one...
February 2, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28124800/trans-fatty-acid-accumulation-in-the-human-placenta
#5
Yoshiro Wada, Shumi Yoshida-Yamamoto, Yoshinao Wada, Masahiro Nakayama, Nobuaki Mitsuda, Hiroyuki Kitajima
Trans fatty acid may impair fetal growth and infant neurodevelopment, but the quantity in a placenta and human tissues remains unknown. To address the issue, a simple and reliable method of quantification is needed. We established a method of quantifying trans-octadecenoic acids (trans-6,8,9,11 18:1 fatty acids, TOAs), a major component of TFA, in human tissue samples, and then determined the TOAs level in the placenta. Oleic acid (OA) (C18:1(9c)) was measured by isotope dilution gas-chromatography mass-spectrometry, and the TOAs level was subsequently calculated based on the ratio of the peak areas for TOAs and OA (TOAs/OA) in the mass chromatogram...
January 26, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28117928/maldi-imaging-mass-spectrometry-reveals-multiple-clinically-relevant-masses-in-colorectal-cancer-using-large-scale-tissue-microarrays
#6
Andrea Hinsch, Malte Buchholz, Sinje Odinga, Carina Borkowski, Christina Koop, Jacob R Izbicki, Marcus Wurlitzer, Till Krech, Waldemar Wilczak, Stefan Steurer, Frank Jacobsen, Eike-Christian Burandt, Phillip Stahl, Ronald Simon, Guido Sauter, Hartmut Schlüter
For identification of clinically relevant masses to predict status, grade, relapse and prognosis of colorectal cancer we applied MALDI imaging mass spectrometry (IMS) to a tissue micro array (TMA) containing formalin-fixed and paraffin-embedded tissue samples from 349 patients. Analysis of our MALDI-IMS data revealed 27 different m/z signals associated with epithelial structures. Comparison of these signals showed significant association with status, grade and Ki-67 labeling index. 15 out of 27 IMS signals revealed a significant association with survival...
January 24, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28112477/correlation-between-the-shape-of-the-ion-mobility-signals-and-the-stepwise-folding-process-of-polylactide-ions
#7
Q Duez, T Josse, V Lemaur, F Chirot, C M Choi, Ph Dubois, Ph Dugourd, J Cornil, P Gerbaux, J De Winter
In the field of polymer characterization, the use of IMMS (Ion Mobility Mass Spectrometry) remains mainly devoted to the temporal separation of cationized oligomers according to their charge states, molecular masses as well as their macromolecular architectures in order to probe the presence of different structures. When analyzing multiply charged polymer ions by IMMS, the most striking feature is the observation of breaking points in the evolution of the average collision cross sections with the number of monomer units...
January 23, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28109035/competitive-benzyl-cation-transfer-proton-transfer-collision-induced-mass-spectrometric-fragmentation-of-protonated-n-n-dibenzylaniline
#8
Ge Ma, Gongye Liu, Shanshan Shen, Yunfeng Chai, Lei Yue, Shunping Zhao, Yuanjiang Pan
Collision-induced dissociation of protonated N,N-dibenzylaniline was investigated by electrospray tandem mass spectrometry. Various fragmentation pathways were dominated by benzyl cation and proton transfer. Benzyl cation transfers from the initial site (nitrogen) to benzylic phenyl or aniline phenyl ring. The benzyl cations transfer to the two different sites and both result in the benzene loss combined with 1,3-H shift. In addition, after the benzyl cation transfers to the benzylic phenyl ring, 1,2-H shift and 1,4-H shift proceed competitively to trigger the diphenylmethane loss and aniline loss respectively...
January 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28102926/sodiation-based-in-source-collision-for-profiling-of-pyranocoumarins-in-radix-peucedani-qianhu-utility-of-sodium-adducts-stability-with-in-source-collision
#9
Wei Yang, Yingfei Li, Chen Kang, Haiyu Zhao, Li Xiang, Chuan Li, Qiao Wang
Full scan mode of liquid chromatography-mass spectrometry equipped with an electrospray ionization source offers a chance on global detection of complicated components; however, the scan mode carries significant challenges in rapidly capturing information of analysts. Sodiation-based in-source collision was proposed here, as a technique for rapid detecting untargeted analytes in full scan analysis, which was based on the stability of sodium adducts and the nonselectivity of in-source collision. Then the technique was applied to profile of angular-type pyranocoumarins (APs) in Radix Peucedani, with full scan analysis performed at two specific in-source collision energy: a high energy 50 V that is tolerated by the sodium adducts of APs, and a low energy 10 V, at which abundant adducts were offered...
January 19, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28098959/influence-of-electronic-and-molecular-structure-on-the-fragmentation-dynamic-of-even-electron-carbocationic-triangulenes-and-helicenes-in-the-gas-phase
#10
Jakob Felix Hitzenberger, Agnes Uhl, Jürgen Schatz, Thomas Drewello
Stable, long-lived organic cations are directly transferred by electrospray ionization (ESI) from solution into the gas phase where their collision-induced dissociations (CID) are studied by tandem mass spectrometry. Three related types of triphenyl carbenium ions are investigated, in which the meta positions are either substituted by methoxy groups or tertiary nitrogen bridges, including Tetramethoxyphenylacridinium (TMPA(+) ), dimethoxyquinacridinium (DMQA(+) ) and triazatriangulenium (TATA(+) ) cations. These ions are triangular in shape with increasing degrees of planarity...
January 18, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28098404/esi-activity-of-br-bf4-clo4-and-bph4-anions-in-the-presence-of-li-and-nbu4-counter-ions
#11
Konrad Koszinowski, Friederike Lissy
To improve our understanding of the electrospray-ionization (ESI) process, we have subjected equimolar mixtures of salts A(+) X(-) (A(+)  = Li(+) , NBu4(+) ; X(-)  = Br(-) , ClO4(-) , BF4(-) , BPh4(-) ) in different solvents (CH3 CN, tetrahydrofuran, CH3 OH, H2 O) to negative-ion mode ESI and analyzed the relative ESI activity of the different anionic model analytes. The ESI activity of the large and hydrophobic BPh4(-) ion greatly exceeds that of the smaller and more hydrophilic anions Br(-) , ClO4(-) , and BF4(-) , which we ascribe to its higher surface activity...
January 18, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28098395/first-uhplc-ms-ms-method-coupled-with-automated-on-line-spe-for-quantification-both-of-tacrolimus-and-everolimus-in-peripheral-blood-mononuclear-cells-and-its-application-on-samples-from-co-treated-pediatric-patients
#12
Debora Pensi, Amedeo De Nicolò, Michele Pinon, Clarissa Pisciotta, Pier Luigi Calvo, Antonello Nonnato, Renato Romagnoli, Francesco Tandoi, Giovanni Di Perri, Antonio D'Avolio
Tacrolimus (TAC, FK-506) and everolimus (EVE, RAD001) are immunosuppressors used to treat pediatric patients undergoing liver transplantation. Their hematic TDM by liquid chromatography became standard practice. However, it does not always reflect concentrations at their active site. Our aim was to develop and validate a new method for the simultaneous TAC and EVE quantification into target cells: Peripheral-Blood-Mononuclear-Cells (PBMCs). PBMCs were collected using Cell-Preparation-Tubes; cells number and MCV were evaluated by an automatic cell counter...
January 18, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28087974/application-of-z-sinapinic-matrix-in-peptide-maldi-ms-analysis
#13
María L Salum, Silvana L Giudicessi, Tobías Schmidt De León, Silvia A Camperi, Rosa Erra-Balsells
Since introduction of sinapinic acid (SA) and α-cyano-4-hydroxycinnamic acid as matrices successful application of matrix assisted laser desorption/ionization mass spectrometry started for protein/polypeptides. Both show some limitations in short peptide analysis because matrix clusters are quite abundant. Cinnamics currently used are E-cinnamics. Here Z-SA as matrix for peptides is studied and compared with E-SA and CHCA. Minor number of clusters are always observed in the low m/z region allowing the detection of short peptides...
January 14, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28074623/characterization-and-application-of-a-self-aspirating-electrospray-source-with-pneumatic-assisted-ionization
#14
Quan Yu, Jianchao Zhang, Kai Ni, Xiang Qian, Xiaohao Wang
A single gas-assisted electrospray ion source developed for ambient mass spectrometry is introduced in this paper. Simultaneous self-aspiration and electrospray could be achieved by using a constant sheath gas flow supplied from a mini air pump. A gas dynamic study of the spray module is carried out for structural optimization. The entire device exhibits a simplified design and has been systematically characterized through both simulated and experimental investigations. According to the results, the ion source exhibited satisfactory stability and the ability for quantitative operation in routine electrospray ionization mass spectrometry...
January 11, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28074602/direct-maldi-ms-analysis-of-the-disulfide-bonds-in-peptide-using-thiosalicylic-acid-as-a-reactive-matrix
#15
Daiki Asakawa, Issey Osaka
The ability of a thiol-containing molecule, thiosalicylic acid (TSA), to function as a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of peptides has been investigated. Although TSA has reducing characteristics, the use of TSA did not cause a reduction-induced MALDI in-source decay (MALDI-ISD), probably because of the weak interactions between the thiol group in TSA and the carboxyl oxygen in the peptide. In contrast, when peptides containing disulfide bonds were analyzed by MALDI with TSA as the matrix, the disulfide bond was partially cleaved owing to the reaction with TSA, producing TSA adducted peptides...
January 10, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28063268/evaluation-of-the-quality-of-herbal-teas-by-dart-tof-ms
#16
Jana Prchalová, František Kovařík, Aleš Rajchl
The paper focuses on the optimization, settings and validation of direct analysis in real time (DART) coupled with time of flight detector (TOF) when used for the evaluation of the quality of selected herbal teas (fennel, chamomile, nettle, linden, peppermint, thyme, lemon balm, marigold, sage, rose hip, St. John's Wort). The ionization mode, the optimal ionization temperature and the type of solvent for sample extraction were optimized. The characteristic compounds of the analysed herbal teas (glycosides, flavonoids, phenolic and terpenic substances, such as chamazulene, anethole, menthol, thymol, salviol, hypericin etc...
January 7, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28061011/simultaneous-enantiomeric-analysis-of-pharmacologically-active-compounds-in-environmental-samples-by-chiral-lc-ms-ms-with-a-macrocyclic-antibiotic-stationary-phase
#17
D Camacho-Muñoz, B Kasprzyk-Hordern
This paper presents a multi-residue method for direct enantioselective separation of chiral pharmacologically active compounds in environmental matrices. The method is based on chiral liquid chromatography and tandem mass spectrometry detection. Simultaneous chiral discrimination was achieved with a macrocyclic glycopeptide-based column with antibiotic teicoplanin as a chiral selector working under reverse phase mode. For the first time, enantioresolution was reported for metabolites of ibuprofen: carboxyibuprofen and 2-hydroxyibuprofen with this chiral stationary phase...
January 6, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/27966255/liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry-identification-and-determination-of-tri-and-hexaaryl-chloro-imidazoles-in-sewage-sludge
#18
J Casado, G Castro, I Rodriguez, M Ramil, R Montes, R Cela
The identification and further quantification of 2-chloro-triarylimidazole (o-Cl-TAI) and its dimer (o-DCl-HABI) in sludge from a sewage treatment plant (STP) is reported for the first time. Liquid chromatography (LC) quadrupole time-of-flight (QTOF) mass spectrometry (MS) was used as analytical technique during screening and determination steps. Pollutants were identified following a post-run search strategy, applying the chlorine mass filter, and characterized by their accurate MS and product ion scan spectra...
December 14, 2016: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/27935159/de-novo-sequencing-of-highly-modified-therapeutic-oligonucleotides-by-hydrophobic-tag-sequencing-coupled-with-lc-ms
#19
Rieko Goto, Shin Miyakawa, Emire Inomata, Tomonori Takami, Junji Yamaura, Yoshikazu Nakamura
Correct sequences are prerequisite for quality control of therapeutic oligonucleotides. However, there is no definitive method available for determining sequences of highly modified therapeutic RNAs, and thereby most of the oligonucleotides have been used clinically without direct sequence determination. In this study, we developed a novel sequencing method called 'hydrophobic tag sequencing'. Highly modified oligonucleotides are sequenced by partially digesting oligonucleotides conjugated with a 5'-hydrophobic tag, followed by liquid chromatography-mass spectrometry analysis...
December 9, 2016: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/27884051/unexpected-interaction-between-deprotonated-biliverdin-and-alcohols-as-studied-by-esi-ms
#20
LETTER
Rafat Franski, Tomasz Kozik
No abstract text is available yet for this article.
November 24, 2016: Journal of Mass Spectrometry: JMS
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