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European Journal of Mass Spectrometry

Mahendra Shukla, Femi M Francis, Jawahar Lal
Conessine, a steroidal alkaloid obtained from the bark and seeds of the plant species of Apocynaceae family, elicits a histamine antagonistic action, selectively for the H3 histaminergic receptors. This alkaloid is used mainly for the treatment of dysentery and helminthic disorders. For the quantification of conessine in serum, a liquid chromatography-tandem mass spectrometry method was developed. Chromatographic separation was achieved on a Zorbax SB-CN column (100 × 4.6 mm, 3.5 µm), and a mobile phase consisting of 90% methanol in aqueous ammonium acetate buffer (pH 3...
June 2018: European Journal of Mass Spectrometry
Kranthikumar Yadav, J Laxmikanth Rao, R Srinivas, R Nagaraj, M V Jagannadham
The detection of post-translational modifications of proteins is an important comprehensive research area. Over the years, proteomic studies involving protein acetylation have attracted a great deal of attention. In the present study, we have focussed on the acetylation of histidine and the intrinsic stability of b1 -ion of oxazolone ring and/or with side chain imidazole bicyclic product. The formation of oxazolone structure may occur when an amino moiety undergoes acetylation reaction and when it is present in the vicinity of the side chain imidazole moiety...
June 2018: European Journal of Mass Spectrometry
Magdalena Frańska, Anna Michalak
The gas-phase stabilities of Tl+ -crown ether complexes and Rb+ -crown ether complexes were studied using the electrospray ionization-collision-induced dissociation-tandem mass spectrometry. Tl+ and Rb+ have identical ionic radii, thus a comparison of the properties of the crown ether complexes with these two cations seems to be justified. The selected crown ethers were 12C4 (it has a cavity smaller than the cation radius), 18C6 (it has a cavity of size similar to the cation radius), 24C8 (it has a cavity greater than the cation radius) and their conjugates...
June 2018: European Journal of Mass Spectrometry
Elena Mitrofanov, Tassilo Muskat, Jürgen Grotemeyer
The dissociation reactions of indocyanine green (also known as cardiogreen) have been studied in a Fourier-transform ion-cyclotron resonance mass spectrometer by the application of unimolecular, collision-induced dissociation and photodissociation using femtosecond laser pulses. Ions were prepared by electrospray ionization (ESI) in various solvents. Depending on the properties of the solvent mixture, the mono sodiated molecule could be measured through cation exchange in various compositions. Using a mixture of methanol/water/formic acid as solvent, protonated ions, formed by exchange of sodium, are predominantly observed...
June 2018: European Journal of Mass Spectrometry
Chongsheng Xu, Nan He, Zhenhua Li, Yanqiu Chu, Chuan-Fan Ding
The binding affinities of cyclodextrins complexation with chlorine (Cl- ), bromine (Br- ) and iodine (I- ), were measured by mass spectrometric titrimetry, and the fitting of the binding constants was based on the concentration measurement of the cyclodextrin equilibrium. The binding constants (lg Ka ) for α-, β- or γ-cyclodextrin with Cl- were 3.99, 4.03 and 4.11, respectively. The gas-phase binding affinity of halide anions for native cyclodextrins was probed by collision-induced dissociation. In collision-induced dissociation, the centre-of-mass frame energy results revealed that in the gas phase, for the same type of cyclodextrin, the stability of the complexes decreased in order: Cl > Br > I, and for the same halide anion, the binding stability of the complex with α-, β- or γ-cyclodextrin decreased in the order: γ-cyclodextrin >β-cyclodextrin > α-cyclodextrin...
June 2018: European Journal of Mass Spectrometry
Liwen Fang, Cheng Dong, Cheng Guo, Jianxing Xu, Qiaoling Liu, Zhirong Qu, Kezhi Jiang
A series of N-(1,3-diphenylallyl)benzenamine derivatives (M) were investigated by electrospray ionization mass spectrometry in the positive-ion mode. Both the anomalous [M-H]+ and the regular [M+H]+ were observed in the ESI mass spectra. The occurrence of [M-H]+ has been supported by accurate mass spectrometry, liquid chromatography mass spectrometry, and tandem mass spectrometry analysis. Calculation results indicated that formation of [M-H]+ is attributed to the ion-molecule reaction of M with the protonated ESI solvent molecule (e...
June 2018: European Journal of Mass Spectrometry
Patricia Wright, Hannah Britt, Cris Lapthorn, Christopher Whitmore
No abstract text is available yet for this article.
April 2018: European Journal of Mass Spectrometry
Medicharla V Jagannadham, D B Kameshwari, P Gayathri, R Nagaraj
A wide variety of post-translational modifications such as oxidation, phosphorylation, glycosylation, methylation, and acetylation play critical roles in cellular functions. Detection of post-translational modifications in proteins is important to understand their crucial roles in cellular functions. Identifying each modification requires special attention in mass spectral acquisition and analysis. Here, we report a mass spectral method for the detection of multiple phosphorylations in peptides by analyzing their products after fragmentation...
April 2018: European Journal of Mass Spectrometry
Diego D Colasurdo, Matías N Pila, Dacio A Iglesias, Sergio L Laurella, Danila L Ruiz
It has been demonstrated that uracil has a preponderant tautomeric form, but it is also known that different tautomers co-exist in this equilibrium. In this work, mass spectrometry is used as a helpful tool to analyse the equilibria, using derivative compounds to forbid the presence of some tautomers and ion trap mass spectrometry to follow relevant fragmentation pathways. Theoretical calculations were performed to confirm tautomers abundance by energy minimization in gas phase. Analysis of mass spectra of uracil, three methyl-substituted uracils, 2-thiouracil and three benzouracils suggest that uracil exists mainly as three tautomers in gas phase: one major structure that corresponds to the classical structure of uracil (pyrimidine-2,4(1H,3H)-dione) bearing two carbonyls and two NH moieties, and two minor enolic forms (4-hydroxypyrimidin-2(1H)-one and 2-hydroxypyrimidin-4(1H)-one)...
April 2018: European Journal of Mass Spectrometry
Yan Feng, Xiaoqiang Pei, Yongjun Cheng, Wenjun Sun, Gang Li, Yongjun Wang, Zhenhua Xi, Huzhong Zhang
In this paper, the effects of constant uniform magnetic fields on a miniature linear ion trap mass spectrometer with hyperbolic electrodes are simulated using SIMION 8.0 3D software. Magnetic fields in different directions have different effects on the trajectories of the trapped ions and the shape of the ion cloud. When the magnetic field is applied in the z-direction, namely the ion injection direction, the magnetic field will cause the ions focusing to the z-axis, and exert a compression effect on the ion cloud...
April 2018: European Journal of Mass Spectrometry
Stefanie Ickert, Johanna Hofmann, Jens Riedel, Sebastian Beck, Kevin Pagel, Michael W Linscheid
Mass spectrometry is applied as a tool for the elucidation of molecular structures. This premises that gas-phase structures reflect the original geometry of the analytes, while it requires a thorough understanding and investigation of the forces controlling and affecting the gas-phase structures. However, only little is known about conformational changes of oligonucleotides in the gas phase. In this study, a series of multiply charged DNA oligonucleotides (n = 15-40) has been subjected to a comprehensive tandem mass spectrometric study to unravel transitions between different ionic gas-phase structures...
April 2018: European Journal of Mass Spectrometry
Yue Li, Jianwen Yu, Zhiming Ruan, Chilai Chen, Ran Chen, Han Wang, Youjiang Liu, Xiaozhi Wang, Shan Li
In conventional high-field asymmetric waveform ion mobility spectrometry signal acquisition, multi-cycle detection is time consuming and limits somewhat the technique's scope for rapid field detection. In this study, a novel intelligent detection approach has been developed in which a threshold was set on the relative error of α parameters, which can eliminate unnecessary time spent on detection. In this method, two full-spectrum scans were made in advance to obtain the estimated compensation voltage at different dispersion voltages, resulting in a narrowing down of the whole scan area to just the peak area(s) of interest...
April 2018: European Journal of Mass Spectrometry
Meiru Guo, Detian Li, Yongjun Cheng, Yongjun Wang, Wenjun Sun, Xiaoqiang Pei, Meng Dong, Xuemin Sheng, Lan Zhao, Yanwu Li
With the rapid development of space technology in China, it is urgent to use mass spectrometer to detect the space environment. In this work, a space miniature magnetic sector mass spectrometer is evaluated, which consists of three subsystems: (1) physical unit, (2) electric control unit, (3) and high voltage power. It has 90° magnetic sector-field analyzer with double trajectory, in which a trajectory measurement range is from 1 to 12 amu, the other range is from 6 to 90 amu.The mass spectrometer has two work models, one is used to measure space neutral gas when the filament of mass spectrometer ion source turned on, the other is used to measure space charged ions when the filament turned off...
April 2018: European Journal of Mass Spectrometry
Patrick D Knight, Theodoros K Karamanos, Sheena E Radford, Alison E Ashcroft
Amyloid diseases represent a growing social and economic burden in the developed world. Understanding the assembly pathway and the inhibition of amyloid formation is key to developing therapies to treat these diseases. The neurodegenerative condition Machado-Joseph disease is characterised by the self-aggregation of the protein ataxin-3. Ataxin-3 consists of a globular N-terminal Josephin domain, which can aggregate into curvilinear protofibrils, and an unstructured, dynamically disordered C-terminal domain containing three ubiquitin interacting motifs separated by a polyglutamine stretch...
February 2018: European Journal of Mass Spectrometry
Alexander D Warren, David J Mitchell, Paul J Gates
There is still a need to develop reliable and robust matrix deposition methods for matrix-assisted laser desorption/ionisation mass spectrometry that are applicable to a range of matrices, solvents and analyte types. This paper presents a robust methodology for the airbrush application of matrices along with the implications of varying the set-up and airbrush parameters. A small number of organic analytes and metal salts are analysed in both positive and negative ion modes to exemplify this methodology. In the analyses with the airbrush deposited matrices, performance was enhanced when compared to standard pipette deposition with the need for a search for sweat spots greatly diminished due to the increase homogeneity of the matrix surface and resultant analyte spots...
February 2018: European Journal of Mass Spectrometry
Joakim S Jestilä, Einar Uggerud
Electrospray ionization of mixtures of succinic acid (here denoted H2 Su) and magnesium chloride in water/methanol give rise to ions of the type ESu- (E = H or ClMg). The unimolecular dissociation of these ions was studied by collisionally induced dissociation mass spectrometry and interpreted by quantum chemical calculations (density functional theory and the composite Gaussian-4 method) of relevant parts of the potential energy surfaces. The major dissociation pathways from HSu- were seen to be dehydration and decarboxylation, while ClMgSu- mainly undergoes decarboxylation...
February 2018: European Journal of Mass Spectrometry
George N Khairallah, Tom Waters, Anthony G Wedd, Richard Aj O'Hair
Two gas-phase catalytic cycles involving C-F bond activation of trifluoroethanol and trifluoroacetic acid were detected by multistage mass spectrometry experiments. A binuclear dimolybdate centre [Mo2 O6 (F)]- acts as the catalyst in each cycle. The first cycle, entered via the reaction of [Mo2 O6 (OH)]- with trifluoroethanol and elimination of water to form [Mo2 O6 (OCH2 CF3 )]- , proceeds via four steps: (1) oxidation of the alkoxo ligand and its elimination as aldehyde; (2) reaction of [Mo2 O5 (OH)]- with trifluoroethanol and elimination of water to form [Mo2 O5 (OCH2 CF3 )]; (3) decomposition of the alkoxo ligand via loss of 1,1 difluoroethene; and (4) reaction of [Mo2 O6 (F)]- with a second equivalent of trifluoroethanol to regenerate Mo2 O6 (OCH2 CF3 )]- ...
February 2018: European Journal of Mass Spectrometry
Jackie A Mosely, Peter Stokes, David Parker, Philip W Dyer, Antonis M Messinis
A novel method has been developed that enables chemical compounds to be transferred from an inert atmosphere glove box and into the atmospheric pressure ion source of a mass spectrometer whilst retaining a controlled chemical environment. This innovative method is simple and cheap to implement on some commercially available mass spectrometers. We have termed this approach inert atmospheric pressure solids analysis probe ( iASAP) and demonstrate the benefit of this methodology for two air-/moisture-sensitive chemical compounds whose characterisation by mass spectrometry is now possible and easily achieved...
February 2018: European Journal of Mass Spectrometry
Vladimir G Zaikin, Anton V Kozlov, Roman S Borisov, Igor Yu Shchapin
The influence of regio-isomerism of even-electron sulfonium ions on tandem electrospray and matrix-assisted laser desorption/ionization mass spectra recorded by using collision-induced dissociation was investigated. The initial organic sulfides belonged to isomeric thiabicyclane series (substituted 7- and 8-thiabicyclo[4.3.0]nonanes, 2- and 3-thiabicyclo[4.4.0]decanes) and phenylthiolanes. To investigate by the abovementioned mass spectrometry methods, the sulfides were preliminary S-alkylated by methyl, ethyl iodides, their deuterated analogs and trialkoxonium tetrafluoroborates to form corresponding sulfonium salts...
February 2018: European Journal of Mass Spectrometry
Bruno Figadére, Tangyuan Cao, Thomas H Morton
The Hofmann elimination of ammonium ions having a single positive charge is demonstrated to exhibit stereospecificity with regard to expulsion of neutral alkene. For the 3-hexyl series of threo and erythro 4-monodeuterated ions (3-hexylammonium ion; N,N,N-trimethyl- d3 -3-hexylammonium ion; N-ethyl-3-hexylammonium ion; N-methyl, N-ethyl-3-hexylammonium ion; N,N-dimethyl, N-ethyl-3-hexylammonium ion), the upper limit of the E:Z ratio of the expelled alkene (r) approaches 2 (the stereospecificity) with a deuterium isotope effect close to 2...
February 2018: European Journal of Mass Spectrometry
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