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European Journal of Mass Spectrometry

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https://www.readbyqxmd.com/read/29436862/differentiation-of-isomeric-haloanilines-by-tosylation-in-combination-with-electrospray-ionization-mass-spectrometry
#1
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...
January 1, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29392979/characterization-of-acetylated-histidine-b1-ion-structure-a-competition-between-oxazolone-and-side-chain-imidazole-moiety
#2
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...
January 1, 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
#3
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...
January 1, 2018: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29334808/identification-of-a-novel-site-of-interaction-between-ataxin-3-and-the-amyloid-aggregation-inhibitor-polyglutamine-binding-peptide-1
#4
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
https://www.readbyqxmd.com/read/29334807/methodologies-for-the-airbrush-application-of-maldi-matrices
#5
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
https://www.readbyqxmd.com/read/29183200/subsequent-radical-fragmentation-reactions-of-n-n-diethylamino-substituted-azobenzene-derivatives-in-a-fourier-transform-ion-cyclotron-resonance-mass-spectrometer-using-collision-induced-dissociation-and-photodissociation
#6
Martin Clemen, Jürgen Grotemeyer
The fragmentation behavior of N, N-diethylamino-substituted azobenzene derivatives is investigated by high-resolving mass spectrometry using a Fourier transform ion cyclotron resonance mass spectrometer. Former investigations by photodissociation as well as collision-induced dissociation experiments used to induce a loss of C3H8 from the diethylamino group. The position of the additional proton in [M + H]+ ions is important due to the sequences of radical fragmentation reactions. Two possibilities arise...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183199/exploration-of-doubtful-cases-of-leucine-and-isoleucine-discrimination-in-mass-spectrometric-peptide-sequencing-by-electron-transfer-and-higher-energy-collision-dissociation-based-method
#7
Sergey V Kovalyov, Sergey S Zhokhov, Ludmila V Onoprienko, Boris V Vaskovsky, Albert T Lebedev
Electron-transfer dissociation (ETD) and electron-transfer and higher-energy collision dissociation (EThcD) spectra of short tryptic peptides with leucine/isoleucine residues in neighboring positions demonstrate intensive w-ions. On the contrary, u-ions possess very low intensities (if present at all). Therefore radical site migration is negligible in the applied conditions while ETD (EThcD) spectra allow for the reliable discrimination of the isomeric residues in the sequencing process. The presence of a fragment ion 43...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183198/evaluation-of-calculated-negative-mode-ion-mobilities-of-small-molecules-in-air
#8
Frank Gunzer
Ion mobility spectrometry is a well-known technique employed for the detection and analysis of gaseous substances. In pharmaceutical applications, it is furthermore used for structural analysis of compounds, especially in combination with mass spectrometry. In this field, the comparison of calculated collision cross sections and ion mobilities of theoretic model compounds with experimental values measured with ion mobility spectrometers helps to determine the compound's structure. For positive mode ion mobility spectrometry, the calculated mobilities using the Trajectory Method show in general a deviation of 10% or less from experimental values...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183197/proton-affinities-and-ion-enthalpies
#9
John L Holmes, Nick A van Huizen, Peter C Burgers
Proton affinities of a number of alkyl acetates (CH3-C(=O)-OR) and of methyl alkanoates (R-C(=O)-OCH3, R=H, alkyl) have been assembled from the literature or measured using the kinetic method. It was observed that the proton affinities for the isomeric species CH3-C(=O)-OR and R-C(=O)-OCH3 are almost identical, an unexpected result as the charge in these protonated ester molecules is largely at the keto carbon atom and so this site should be more sensitive to alkyl substitution. Analysis of the data, including those from lone pair ionisation and core-electron ionisation experiments available from the literature, indicate that after protonation, extensive charge relaxation (or polarisation) takes place (as is also the case, according to the literature, after core-electron ionisation)...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183196/substituent-effects-in-the-decarboxylation-reactions-of-coordinated-arylcarboxylates-in-dinuclear-copper-complexes-napy-cu2-o2cc6h4x-%C3%A2
#10
Qiuyan Jin, Jiaye Li, Alireza Ariafard, Allan J Canty, Richard Aj O'Hair
A combination of gas-phase ion trap mass spectrometry experiments and density functional theory (DFT) calculations have been used to examine the role of substituents on the decarboxylation of 25 different coordinated aromatic carboxylates in binuclear complexes, [(napy)Cu2(O2CC6H4X)]+, where napy is the ligand 1,8-naphthyridine (molecular formula, C8H6N2) and X = H and the ortho ( o), meta ( m) and para ( p) isomers of F, Br, CN, NO2, CF3, OAc, Me and MeO. Two competing unimolecular reaction pathways were found: decarboxylation to give the organometallic cation [(napy)Cu2(C6H4X)]+ or loss of the neutral copper benzoate to yield [(napy)Cu]+...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183195/analytical-techniques-for-the-characterization-of-antibody-drug-conjugates-challenges-and-prospects
#11
Rabin Neupane, Jonas Bergquist
Antibody drug conjugates are increasingly being researched for the treatment of cancer. Accurate and reliable characterization of ADCs is inevitable for their development as potential therapeutic agent. Different analytical techniques have been used in order to decipher heterogeneous nature of antibody drug conjugates, enabling successful characterization. This review will summarize specially three major analytical tools i.e. UV-Vis spectroscopy, liquid chromatography, and mass spectrometry used in characterization of antibody drug conjugates...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183194/multidimensional-mass-spectrometry-characterization-of-isomeric-biodegradable-polyesters
#12
Sahar Sallam, Yuanyuan Luo, Matthew L Becker, Chrys Wesdemiotis
The biodegradable polyester copolymer poly(propylene fumarate) (PPF) is increasingly utilized in bone tissue engineering studies due to its suitability as inert cross-linkable scaffold material. The well-defined poly(propylene fumarate) oligomers needed for this purpose are synthesized by post-polymerization isomerization of poly(propylene maleate), which is prepared by ring opening polymerization of maleic anhydride and propylene oxide. In this study, multidimensional mass spectrometry methodologies, interfacing matrix-assisted laser desorption ionization and electrospray ionization with mass analysis, tandem mass spectrometry fragmentation and/or ion mobility mass spectrometry, have been employed to characterize the composition, end groups, chain connectivity and isomeric purity of the isomeric copolyesters poly(propylene maleate)and poly(propylene fumarate)...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183193/mass-spectrometric-characterization-of-protein-structures-and-protein-complexes-in-condensed-and-gas-phase
#13
Yelena Yefremova, Bright D Danquah, Kwabena Fm Opuni, Reham El-Kased, Cornelia Koy, Michael O Glocker
Proteins are essential for almost all physiological processes of life. They serve a myriad of functions which are as varied as their unique amino acid sequences and their corresponding three-dimensional structures. To fulfill their tasks, most proteins depend on stable physical associations, in the form of protein complexes that evolved between themselves and other proteins. In solution (condensed phase), proteins and/or protein complexes are in constant energy exchange with the surrounding solvent. Albeit methods to describe in-solution thermodynamic properties of proteins and of protein complexes are well established and broadly applied, they do not provide a broad enough access to life-science experimentalists to study all their proteins' properties at leisure...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183192/proton-induced-reactions-of-2-2-paracyclophane-in-the-gas-phase-a-study-by-ft-icr-spectrometry-and-dft-calculation
#14
Heinz-Hermann Büker, Hans-Friedrich Grützmacher
The reactions of the [2-2]-paracyclophane 1 and the [2-2]-metaparacyclopane 2 in the gas phase after protonation by CI(CH4) or CI(I-C4H10) were studied by FT-ICR mass spectrometry. The ions C16H17+ produced in the external ion source of the FT-ICR instrument were transferred into the ICR cell containing the neutral reactant, and the reactions were analyzed measuring the efficiency of the transfer of a proton to a series of bases with known proton affinity and gas phase basicity as well as the efficiency of the ion-molecule reaction with ethyl vinyl ether...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183191/mechanisms-governing-the-fragmentation-of-glycerophospholipids-containing-choline-and-ethanolamine-polar-head-groups
#15
Benoit Colsch, François Fenaille, Anna Warnet, Christophe Junot, Jean-Claude Tabet
Glycerophospholipids are the major amphiphilic molecules found in the plasma membrane bilayer of all vertebrate cells. Involved in many biological processes, their huge structural diversity and large concentration scale make their thorough characterization extremely difficult in complex biological matrices. Mass spectrometry techniques are now recognized as being among the most powerful methods for the sensitive and comprehensive characterization of lipids. Depending on the experimental conditions used during electrospray ionization mass spectrometry experiments, glycerophospholipids can be detected as different molecular species (e...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183190/basic-poly-propylene-glycols-as-reference-compounds-for-internal-mass-calibration-in-positive-ion-matrix-assisted-laser-desorption-ionization-mass-spectrometry
#16
Jürgen H Gross
Basic poly(propylene glycols), commercially available under the trade name Jeffamine, are evaluated for their potential use as internal mass calibrants in matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry. Due to their basic amino endgroups Jeffamines are expected to deliver [M+H]+ ions in higher yields than neutral poly(propylene glycols) or poly(ethylene glycols). Aiming at accurate mass measurements and molecular formula determinations by matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry, four Jeffamines (M-600, M-2005, D-400, D-230) were thus compared...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183189/editor-s-personal-foreword
#17
Jürgen Grotemeyer
No abstract text is available yet for this article.
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183188/prof-peter-j-derrick-1945-2017
#18
Jürgen Grotemeyer
No abstract text is available yet for this article.
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183187/peter-j-derrick-and-the-grand-scale-magnificent-mass-machine-mass-spectrometer-at-warwick
#19
A W Colburn, Peter J Derrick, Richard D Bowen
The value of the Grand Scale 'Magnificent Mass Machine' mass spectrometer in investigating the reactivity of ions in the gas phase is illustrated by a brief analysis of previously unpublished work on metastable ionised n-pentyl methyl ether, which loses predominantly methanol and an ethyl radical, with very minor contributions for elimination of ethane and water. Expulsion of an ethyl radical is interpreted in terms of isomerisation to ionised 3-pentyl methyl ether, via distonic ions and, possibly, an ion-neutral complex comprising ionised ethylcyclopropane and methanol...
December 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29183186/a-new-approach-for-accurate-mass-assignment-on-a-multi-turn-time-of-flight-mass-spectrometer
#20
Toshinobu Hondo, Kirk R Jensen, Jun Aoki, Michisato Toyoda
A simple, effective accurate mass assignment procedure for a time-of-flight mass spectrometer is desirable. External mass calibration using a mass calibration standard together with an internal mass reference (lock mass) is a common technique for mass assignment, however, using polynomial fitting can result in mass-dependent errors. By using the multi-turn time-of-flight mass spectrometer infiTOF-UHV, we were able to obtain multiple time-of-flight data from an ion monitored under several different numbers of laps that was then used to calculate a mass calibration equation...
December 2017: European Journal of Mass Spectrometry
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