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Journal of Mass Spectrometry: JMS

Ákos Kuki, Lajos Nagy, Miklós Zsuga, Sándor Kéki
The classical semi-quantitative Rice-Ramsperger-Kassel (RRK) theory was used for the calculation of the internal energy dependent reaction rate coefficient of the collision-induced dissociation (CID) reaction in tandem mass spectrometry (MS/MS). The survival yield (SY) was determined by the reaction rate equation for the unimolecular dissociation of the precursor ion. The parameters of the rate equation and the RRK model were approximated based on the instrumental conditions. We used the RRK equation for the description of the basic behavior of the fragmentation reactions and for the estimation of the internal energy of the precursor ion...
July 21, 2017: Journal of Mass Spectrometry: JMS
Argitxu Esquivel, Xavier Matabosch, Aristotelis Kotronoulas, Georgina Balcells, Jesús Joglar, Rosa Ventura
Studies on steroid metabolism are of utmost importance to improve the detection capabilities of anabolic androgenic steroids (AAS) misuse in sports drug testing. In humans, glucuronoconjugates are the most abundant phase II metabolites of AAS. Bis-glucuronidation is a reaction where two separated functional groups on the same molecule are conjugated with glucuronic acid. These metabolites have not been studied in depth for steroids and could be interesting markers for doping control. The aim of the present work was to study the ionization and collision induced dissociation of steroid bis-glucuronides to be able to develop mass spectrometric analytical strategies for their detection in urine samples after AAS administration...
July 21, 2017: Journal of Mass Spectrometry: JMS
David Bongiorno, Valentina Calabrese, Leopoldo Ceraulo, Serena Indelicato, Vincenzo Turco Liveri
The ability of positively charged aggregates of the surfactant (1R,2S)-Dodecyl(2-hydroxy-1-methyl-2-phenylethyl)dimethylammonium bromide (DMEB) to incorporate D- or L-tryptophan in the gas-phase has been investigated by electrospray ion mobility mass spectrometry (ESI-IM-MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T(+) ) and deprotonated (T(-) ) tryptophan are effectively included into the aggregates whereas, tryptophan in zwitterionic (T(0) ) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones...
July 21, 2017: Journal of Mass Spectrometry: JMS
Yunfeng Chai, Yunlong Shao, Lu Wang, Lin Wang
In electrospray ionization tandem mass spectrometry of protonated 1-benzoylamines (1-benzoylpiperadine, 1-benzoylmorpholine, and 1-benzoyl-4-methylpiperazine), the dominant fragmentation pathway was amide bond cleavage to form benzoyl cation and neutral amine. Meanwhile, in their fragmentations, an interesting loss of benzaldehyde (106 Da) was observed and identified to derive from hydride transfer reaction between the benzoyl cation and amine. A stepwise mechanism for loss of 106 Da (benzene and CO) could be excluded with the aid of deuterium labeling experiment...
July 14, 2017: Journal of Mass Spectrometry: JMS
Vadim Shevyrin, Yuri Shafran
Differentiation of new psychoactive substance (NPS), 6-(2-methylaminopropyl)benzofuran (6-MAPB), and its positional isomer, 2-(2-methylaminopropyl)benzofuran (2-MAPB), by means of gas chromatography/mass spectrometry (GC/MS) with quadrupole detection is ambiguous. Reliable distinguishing of the two isomers could be achieved by MS/MS spectra recorded after collision-induced dissociation (CID) of precursor ions. Both electron ionization (EI) and electrospray ionization (ESI) methods could be used for these purposes...
July 14, 2017: Journal of Mass Spectrometry: JMS
A F Lago, R D Januário, R L Cavasso Filho, M Simon, J Z Dávalos
Time of flight mass spectrometry, electron-ion coincidence and ion yield spectroscopy were employed to investigate for the first time the thiazole (C3 H3 NS) molecule in the gas phase excited by synchrotron radiation in the soft X-ray domain. Total Ion Yield and PEPICO spectra were recorded as a function of the photon energy in the vicinity of the carbon K edge (C1s). The C1s resonant transitions as well as the core ionization thresholds have been determined from the profile of TIY spectrum and the features were discussed...
July 12, 2017: Journal of Mass Spectrometry: JMS
Cuizhu Wang, Nanqi Zhang, Zhenzhou Wang, Zeng Qi, Bingzhen Zheng, Pingya Li, Jinping Liu
Platycodon grandiflorum (PG) is extensively used for treating cough, excessive phlegm, sore throat, bronchitis and asthma. Whereas Adenophora stricta (AS) is commonly used to reduce phlegm, clear lung and tonify stomach. Due to similar appearances, PG is sometimes adulterated with cheap AS so as to gain profits. And this will inevitably result in different pharmacological property. In order to further clarify the differences in the chemical composition of these two Chinese herbs, the ultra-high performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) coupled with UNIFI platform was used to establish a reliable, simple, sensitive and rapid analytical method...
July 7, 2017: Journal of Mass Spectrometry: JMS
Svetlana Tsizin, Boaz Seemann, Tal Alon, Aviv Amirav
We report the observation of a new physical phenomenon of the addition of two hydrogen atoms to molecular ions thus forming [M+2H](+) ions. We demonstrate such second hydrogen atom abstraction onto the molecular ions of pentaerythritol and trinitrotoluene (TNT). We used both GC-MS with supersonic molecular beam (SMB) with methanol added into its make-up gas and electron ionization LC-MS with SMB with methanol as the LC solvent. We found that the formation of methanol clusters resulted upon electron ionization in the formation of dominant protonated pentaerythritol ion at m/z=137 plus about 70% relative abundance of pentaerythritol molecular ion with two additional hydrogen atoms at m/z=138 which is well above the 5...
July 7, 2017: Journal of Mass Spectrometry: JMS
M Peng, S Li, J Wu, Y Guo, S Cao, Y Zhao
Sartans and related analogues with 5-oxo-l, 2, 4-oxadiazole ring and tetrazole ring are investigated in detail using collision-induced dissociation (CID) method in positive ion mode by electrospray ionization tandem mass spectrometry (ESI-MS(n) ). It is found that, the protonated sartans and related analogues tend to form the N-substituted-3- substituted phenanthridin-6-amine ion which has a large conjugative structure. The possible fragmentation pathways were proposed for the first time, and the key structure of product ions were confirmed by high resolution tandem mass spectrometry and theoretical calculation...
July 5, 2017: Journal of Mass Spectrometry: JMS
T Fouquet, R B Cody, H Sato
No abstract text is available yet for this article.
July 3, 2017: Journal of Mass Spectrometry: JMS
S Meyer, A Riedo, M B Neuland, M Tulej, P Wurz
Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas, and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and thus, a large amount of data to be analysed...
June 30, 2017: Journal of Mass Spectrometry: JMS
T Guaratini, L G P Feitosa, D B Silva, N P Lopes, J L C Lopes, R Vessecchi
Alkaloids from plants of the genus Erythrina display important biological activities, including anxiolytic action. Characterization of these alkaloids by mass spectrometry (MS) has contributed to the construction of a spectral library, has improved understanding of their structures, and has supported the proposal of fragmentation mechanisms in light of density functional calculations (DFT). In this study, we have used low- and high-resolution MS(n) analyses to investigate the fragmentation patterns of erythrinian alkaloids; we have employed the B3LYP/6-31+G(d,p) model to obtain their reactive sites...
June 23, 2017: Journal of Mass Spectrometry: JMS
R Pepin, C J Shaffer, F Tureček
We report diazirine photochemical tags that can be incorporated at peptide N-termini and in lysine residues using a simple solid-state alkylation procedure. The diazirine-tagged peptides are used for photochemical carbene formation at 355 nm and crosslinking of non-covalent peptide-peptide ion complexes in the gas-phase. The new tags allow one to control the charge sites in the complexes and use tandem mass spectrometry for gas-phase sequencing to localize the cross links.
June 20, 2017: Journal of Mass Spectrometry: JMS
H Zhang, A Bibi, H Lu, J Han, H Chen
It is of sustainable interest to improve the sensitivity and selectivity of the ionization process, especially for direct analysis of complex samples without matrix separation. Herein, four ambient ionization methods including desorption atmospheric pressure chemical ionization (DAPCI), heat-assisted desorption atmospheric pressure chemical ionization (heat-assisted DAPCI), microwave plasma torch (MPT), and internal extractive electrospray ionization (iEESI) were employed for comparative analysis of the navel orange tissue samples by mass spectrometry...
June 19, 2017: Journal of Mass Spectrometry: JMS
J Schätti, U Sezer, S Pedalino, J P Cotter, M Arndt, M Mayor, V Köhler
Amino acids are essential building blocks of life and fluorinated derivatives have gained interest in chemistry and medicine. Modern mass spectrometry has enabled the study of oligo- and polypeptides as isolated entities in the gas phase, but predominantly as singly or even multiply charged species. While laser desorption of neutral peptides into adiabatically expanding supersonic noble gas jets is possible, UV-VIS spectroscopy, electric or magnetic deflectometry as well as quantum interferometry would profit from the possibility to prepare thermally slow molecular beams...
June 12, 2017: Journal of Mass Spectrometry: JMS
M Bouza, J Fandino, N Bordel, R Pereiro, A Sanz-Medel
Pulsed glow discharge (PGD) coupled to time of flight mass spectrometry (TOFMS) has been investigated for volatile organic compounds (VOCs) identification and determination. Optimization of PGD operational conditions (chamber design, applied power, pressure and duty cycle) was performed using acetone and benzene as model compounds. During the different optimizations, molecular, fragment and elemental information were obtained when characteristic GD pulse regions were measured. An exploratory study for several VOCs (lineal hydrocarbons, oxygen-containing compounds and aromatic compounds) revealed the capability of the PGD to provide crucial information to elucidate structures (fragments), molecular ions or even proton affinity nature of the molecules; this last information is a consequence of the enriched proton environment generated along the afterglow region for the ionization chamber used...
June 12, 2017: Journal of Mass Spectrometry: JMS
C Schueuermann, P Bremer, P Silcock
No abstract text is available yet for this article.
June 9, 2017: Journal of Mass Spectrometry: JMS
E A da Silva-Junior, C R Paludo, D R Gouvea, M J Kato, N A J C Furtado, N P Lopes, R Vessecchi, M T Pupo
Piplartine, an alkaloid produced by plants in the genus Piper, displays promising anticancer activity. Understanding the gas-phase fragmentation of piplartine by electrospray ionization tandem mass spectrometry can be a useful tool to characterize biotransformed compounds produced by in vitro and in vivo metabolism studies. As part of our efforts to understand natural product fragmentation in electrospray ionization tandem mass spectrometry, the gas-phase fragmentation of piplartine and its two metabolites 3,4-dihydropiplartine and 8,9-dihydropiplartine, produced by the endophytic fungus Penicillium crustosum VR4 biotransformation were systematically investigated...
June 5, 2017: Journal of Mass Spectrometry: JMS
A H El-Khatib, Y He, D Esteban-Fernández, M W Linscheid
DOTA derivatives are applied in quantitative proteomics owing to their ability to react with different functional groups, to harbor lanthanoides and hence their compatibility with molecular and elemental mass spectrometry. The new DOTA derivatives, namely Ln-MeCAT-Click and Ln-DOTA-Dimedone, allow efficient thiol labeling and targeting sulfenation as an important post-translational modification, respectively. Quantitative applications require the investigation of fragmentation behavior of these reagents. Therefore, the fragmentation behavior of Ln-MeCAT-Click and Ln-DOTA-Dimedone was studied using collision-induced dissociation (CID), infrared multiphoton dissociation (IRMPD) and higher-energy collision dissociation (HCD) using different energy levels and the efficiency of reporter ion production was estimated...
June 2, 2017: Journal of Mass Spectrometry: JMS
N D Schmitt, J N Agar
Conformational change and modification of proteins are involved in many cellular functions. However, they can also have adverse effects that are implicated in numerous diseases. How structural change promotes disease is generally not well understood. This perspective illustrates how mass spectrometry (MS), followed by toxicological and epidemiological validation, can discover disease-relevant structural changes and therapeutic strategies. We (with our collaborators) set out to characterize the structural and toxic consequences of disease-associated mutations and post-translational modifications (PTMs) of the cytosolic antioxidant protein Cu/Zn-Superoxide dismutase (SOD1)...
May 30, 2017: Journal of Mass Spectrometry: JMS
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