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European Journal of Mass Spectrometry

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https://www.readbyqxmd.com/read/30205710/gas-phase-metal-ion-chelation-investigated-with-irmpd-spectroscopy-a-brief-review-of-robert-dunbar-s-contributions
#1
Jos Oomens, Nicolas C Polfer, Giel Berden, John R Eyler
With the passing of Prof. Robert C. Dunbar on 31 October 2017, the field of ion chemistry lost one of its modern heroes. Throughout his career in mass spectrometry, two of his main research interests involved the interaction of trapped ions with electromagnetic radiation and the chelation motifs of metal ions with organic ligands. The focus of his early career was on the fundamental processes that take place in molecules upon ultraviolet and infrared excitation. From 2003 to 2017, his scientific interests shifted to more structural questions, notably to resolving the structures and binding motifs of metal ion chelation complexes by application of infrared photodissociation spectroscopy...
September 11, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/30189754/relative-glycosidic-bond-stabilities-of-naturally-occurring-methylguanosines-7-methylation-is-intrinsically-activating
#2
Zachary J Devereaux, Y Zhu, M T Rodgers
The frequency and diversity of posttranscriptional modifications add an additional layer of chemical complexity beyond canonical nucleic acid sequence. Methylations are particularly frequently occurring and often highly conserved throughout the kingdoms of life. However, the intricate functions of these modified nucleic acid constituents are often not fully understood. Systematic foundational research that reduces systems to their minimum constituents may aid in unraveling the complexities of nucleic acid biochemistry...
September 6, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/30189753/the-hno-radical-anion-a-proposed-intermediate-in-diazeniumdiolate-synthesis-using-nitric-oxide-and-alkoxides
#3
Zhe-Chen Wang, Ya-Ke Li, Sheng-Gui He, Veronica M Bierbaum
The strategy of synthesizing diazeniumdiolates (X-N(O)=NO- ) through the coexistence of nitric oxide and alkoxides (RO- ) was introduced by Wilhelm Traube 120 years ago. Today, despite the wide use of diazeniumdiolate derivatives to release nitric oxide in the treatment of cancer, the first step of the reaction mechanism for diazeniumdiolate synthesis remains a mystery and is thought to be complex. We have studied the gas-phase reactions of nitric oxide with alkoxides at room temperature. An electron-coupled hydrogen transfer is observed, and the radical anion HNO- is the only ionic product in these reactions...
September 6, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/30071758/qualitative-analysis-of-schizonepeta-annua-pall-schischk-essential-oil-by-gas-chromatography-quadrupole-time-of-flight-mass-spectrometry
#4
Xi Bai, Jumai Maitusong, Bakri Mahinur, Haji A Aisa, Maitinuer Maiwulanjiang
In this study, a method for the qualitative analysis of small molecular compounds in Schizonepeta annua (Pall.) Schischk essential oil was established based on gas chromatography-quadrupole time-of-flight mass spectrometry. In addition to an automated search of the NIST library, the identification of oxygenated monoterpenes, phenolic esters, and phenolic compounds was achieved by two additional strategies. One strategy involved comparing the relative errors of accurate masses measured for ions in the experimental spectra with those calculated for fragments identified from the NIST database of candidate matches...
August 2, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/30041545/optimization-of-carbamylation-conditions-and-study-on-the-effects-on-the-product-ions-of-carbamylation-and-dual-modification-of-the-peptide-by-q-tof-ms
#5
Cheng Guo, Xuefeng Guo, Lei Zhao, Dandan Chen, Jin Wang, Jia Sun
Modified peptides fragmented by collision-induced dissociation can offer additional sequence information, which is beneficial for the de novo sequencing of peptides. Here, the model peptide VQGESNDLK was carbamylated. The optimal conditions were as follows: temperature of 90℃, pH of 7, and the time of 60 min. Then, we studied the b- and y-series ions of the native, carbamylated, and dual-modified peptides. The results were as follows. The short carbamylated peptides (≤10 amino acid residues) produced more b-series ions (including b1 ion)...
July 24, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29759016/improving-the-sensitivity-of-miniature-linear-ion-trap-mass-spectrometer-by-a-dc-voltage-applied-on-the-eject-electrodes
#6
Gang Li, Detian Li, Yongjun Cheng, Wenjun Sun, Xiaoqiang Pei, Xiaodong Han, Huzhong Zhang, Yongjun Wang, Jian Sun, Meng Dong
A miniaturized linear ion trap mass spectrometer with continuous atmospheric pressure interface has been built in our lab. Significant extension in mass range and reduction in power consumption have been realized by the supplemental alternating current frequency scan mode. However, relatively poor sensitivity has been witnessed, which is directly dominated by the detection efficiency of the ion detector. Theoretical analysis has been implemented to find ways to improve the detection efficiency. The results show that enhanced sensitivity can be obtained by applying a direct current voltage on the pair of electrodes in eject direction...
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29629565/a-reliable-and-stable-method-for-the-determination-of-foretinib-in-human-plasma-by-lc-ms-ms-application-to-metabolic-stability-investigation-and-excretion-rate
#7
Mohamed W Attwa, Adnan A Kadi, Hany W Darwish, Sawsan M Amer, Haitham Alrabiah
Foretinib (GSK1363089) is a multiple receptor tyrosine kinases inhibitor. In this study, a reliable, fast liquid chromatography-tandem mass spectrometric method was described for assaying foretinib in plasma, urine, and rat liver microsome samples. Simple extraction procedure by protein preciptation with acetonitrile was implemented for foretinib and brigatinib (internal standard) analysis. Chromatographic resolution of analytes was achieved on C18 column with the help of isocratic mobile phase. The binary mobile phase consisted of 60% ammonium formate (10 mM, pH 4...
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29498292/measuring-the-effects-of-coulomb-repulsion-via-signal-decay-in-an-atmospheric-pressure-laser-ionization-ion-mobility-spectrometer
#8
Marvin Ihlenborg, Ann-Kathrin Schuster, Jürgen Grotemeyer, Frank Gunzer
Using lasers in ion mobility spectrometry offers a lot of advantages compared to standard ionization sources. Especially, the ion yield can be drastically increased. It can, however, reach levels where the Coulomb repulsion leads to unwanted side effects. Here, we investigate how the Coulomb repulsion can be detected apart from the typical signal broadening by measuring effects created already in the reaction region and comparing them with corresponding finite element method simulations.
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29482363/method-development-for-the-determination-of-1-1-dimethylhydrazine-by-the-high-performance-liquid-chromatography-mass-spectrometry-technique
#9
Igors Susinskis, Peteris Mekss, Juris Hmelnickis
Unsymmetrical dimethyl hydrazine is highly toxic, carcinogenic compound, widely used for organic synthesis and drug development. Therefore, due to its high reactivity, direct analysis is problematic. Current study proposes to use derivatization reaction to increase selectivity and sensitivity of high-performance liquid chromatography-mass spectrometry method. Different derivatization agents were tested and optimal reaction media was found. Derivatization was performed by using small amounts of reagents to lower the cost of analysis...
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29482362/quadrupole-mass-filter-acceptance-in-stability-island-created-by-double-frequency-quadrupole-excitation
#10
N V Konenkov, M A Korzhavchikov, V A Stepanov, O E Trunina
Increase in quadrupole mass filter resolution at separation in narrow band stability island (X-band) formed by biharmonic resonance excitation of ion oscillation is discussed. X-band and the normal working quadrupole mass filter modes are compared at theoretical resolution of 10,000 and different separation times. Transmission curves, acceptance ellipses parameters, and acceptance characteristics are obtained by numerical simulation. Transmission coefficients are approximately the same in both modes. Dependence of acceptance ellipses parameters on ion inlet phases has a complicated oscillating form in the X-band mode...
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29436862/differentiation-of-isomeric-haloanilines-by-tosylation-in-combination-with-electrospray-ionization-mass-spectrometry
#11
Shanshan Wang, Yuanyuan Cheng, Mengmeng Chen, Kezhi Jiang
Differentiation of the isomeric haloanilines still remains a challenging and necessary analytic task due to their identical retention time in chromatography and similar mass spectra. In this work, p-tosylation of haloanilines by reaction of haloanilines with p-toluenesulfonyl chloride resulted in the corresponding N-tosyl haloanilines. Fragmentation of protonated N-tosyl haloanilines in electrospray ionization tandem mass spectrometry (ESI-MS/MS) mainly resulted in tosyl cation, haloaniline radical cation, and halohydroxyaniline radical cation...
August 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29554815/liquid-chromatography-tandem-mass-spectrometry-method-for-the-quantification-of-a-potent-h-3-receptor-antagonist-conessine-in-serum-and-its-application-to-pharmacokinetic-studies
#12
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
https://www.readbyqxmd.com/read/29392979/characterization-of-acetylated-histidine-b-1-ion-structure-a-competition-between-oxazolone-and-side-chain-imidazole-moiety
#13
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
https://www.readbyqxmd.com/read/29320880/gas-phase-relative-stabilities-of-tl-crown-ether-complexes-and-rb-crown-ether-complexes
#14
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
https://www.readbyqxmd.com/read/29277100/indocyanine-green-ms-ms-investigations-using-femtosecond-laser-pulse-photodissociation-and-collision-induced-dissociation
#15
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
https://www.readbyqxmd.com/read/29271243/exploring-halide-anion-affinities-to-native-cyclodextrins-by-mass-spectrometry-and-molecular-modelling
#16
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
https://www.readbyqxmd.com/read/29232977/two-competing-ionization-processes-in-esi-ms-analysis-of-n-1-3-diphenylallyl-benzenamines-formation-of-the-unusual-m-h-ion-versus-the-regular-m-h-ion
#17
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
https://www.readbyqxmd.com/read/29512436/the-38th-bmss-annual-meeting-royal-northern-college-of-music-manchester-5th-to-7th-september-2017
#18
Patricia Wright, Hannah Britt, Cris Lapthorn, Christopher Whitmore
No abstract text is available yet for this article.
April 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29264929/detection-of-peptides-with-intact-phosphate-groups-using-maldi-tof-tof-and-comparison-with-the-esi-ms-ms
#19
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
https://www.readbyqxmd.com/read/29232994/tautomerism-of-uracil-and-related-compounds-a-mass-spectrometry-study
#20
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
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