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Journal of the American Society for Mass Spectrometry

Kathryn M Davis, Abraham K Badu-Tawiah
The exposure of an aqueous-based liquid drop containing amines and graphite particles to plasma generated by a corona discharge results in heterogeneous aerobic dehydrogenation reactions. This green oxidation reaction occurring in ambient air afforded the corresponding quinolines and nitriles from tetrahydroquinolines and primary amines, respectively, at >96% yields in less than 2 min of reaction time. The accelerated dehydrogenation reactions occurred on the surface of a low energy hydrophobic paper, which served both as container for holding the reacting liquid drop and as a medium for achieving paper spray ionization of reaction products for subsequent characterization by ambient mass spectrometry...
October 20, 2016: Journal of the American Society for Mass Spectrometry
Andrew P Storey, Offer M Zeiri, Steven J Ray, Gary M Hieftje
The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level...
October 18, 2016: Journal of the American Society for Mass Spectrometry
Guillaume Van der Rest, Human Rezaei, Frédéric Halgand
Prion protein is involved in deadly neurodegenerative diseases. Its pathogenicity is linked to its structural conversion (α-helix to β-strand transition). However, recent studies suggest that prion protein can follow a plurality of conversion pathways, which hints towards different conformers that might coexist in solution. To gain insights on the plasticity of the ovine prion protein (PrP) monomer, wild type (A136, R154, Q171), mutants and deletions of ARQ were studied by traveling wave ion mobility experiments coupled to mass spectrometry...
October 18, 2016: Journal of the American Society for Mass Spectrometry
Will Kew, Ian Goodall, David Clarke, Dušan Uhrín
Scotch Whisky is an important product, both culturally and economically. Chemically, Scotch Whisky is a complex mixture, which comprises thousands of compounds, the nature of which are largely unknown. Here, we present a thorough overview of the chemistry of Scotch Whisky as observed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Eighty-five whiskies, representing the majority of Scotch Whisky produced and sold, were analyzed by untargeted high-resolution mass spectrometry. Thousands of chemical formulae were assigned for each sample based on parts-per-billion mass accuracy of FT-ICR MS spectra...
October 17, 2016: Journal of the American Society for Mass Spectrometry
Rima Ait-Belkacem, Marialaura Dilillo, Davide Pellegrini, Avinash Yadav, Erik L de Graaf, Liam A McDonnell
Atmospheric pressure MALDI on a Q-Exactive instrument was optimized for in-source decay and pseudo-MS(3). The dependence of AP-MALDI ISD on the MALDI liquid matrix was investigated for peptides and proteins. The liquid matrices enabled long-life ISD signal, and exhibited high fragment ion yield and signal stability. Extensive a-, b-, c-, y-, and z-type fragment series were observed depending on the matrix used but were most extensive with 2,5-DHB. Complete sequence coverage of small peptide and intact protein-terminus sequence tags were obtained and confirmed using HCD as a pseudo-MS(3) method...
October 17, 2016: Journal of the American Society for Mass Spectrometry
Matthew T Campbell, Gary L Glish
Differential ion mobility spectrometry (DIMS) is capable of separating components of complex mixtures prior to mass spectrometric analysis, thereby increasing signal-to-noise and signal-to-background ratios on millisecond timescales. However, adding a DIMS device to the front end of a mass spectrometer can reduce the signal intensity of subsequent mass spectrometric analysis. This is a result, in part, of ions lost due to inefficient transfer of ions from the DIMS device through the aperture leading into the mass spectrometer...
October 17, 2016: Journal of the American Society for Mass Spectrometry
Akimasa Fujihara, Naoto Maeda, Thuc N Doan, Shigeo Hayakawa
Chiral transmission between monosaccharides and amino acids via photodissociation in the gas phase was examined using a tandem mass spectrometer fitted with an electrospray ionization source and a cold ion trap in order to investigate the origin of the homochirality of biomolecules in molecular clouds. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of the monosaccharide enantiomers glucose (Glc) and galactose (Gal) with protonated L-tryptophan H(+)(L-Trp) were obtained by photoexcitation of the indole ring of L-Trp...
October 13, 2016: Journal of the American Society for Mass Spectrometry
Anna C Susa, Zijie Xia, Henry Y H Tang, John A Tainer, Evan R Williams
Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same...
October 12, 2016: Journal of the American Society for Mass Spectrometry
Jared B Shaw, Tzu-Yung Lin, Franklin E Leach, Aleksey V Tolmachev, Nikola Tolić, Errol W Robinson, David W Koppenaal, Ljiljana Paša-Tolić
We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins...
October 12, 2016: Journal of the American Society for Mass Spectrometry
Maha T Abutokaikah, Shanshan Guan, Benjamin J Bythell
Substitution of proline by pipecolic acid, the six-membered ring congener of proline, results in vastly different tandem mass spectra. The well-known proline effect is eliminated and amide bond cleavage C-terminal to pipecolic acid dominates instead. Why do these two ostensibly similar residues produce dramatically differing spectra? Recent evidence indicates that the proton affinities of these residues are similar, so are unlikely to explain the result [Raulfs et al., J. Am. Soc. Mass Spectrom. 25, 1705-1715 (2014)]...
October 11, 2016: Journal of the American Society for Mass Spectrometry
Cosima Damiana Calvano, Giovanni Ventura, Massimo Trotta, Giuliana Bianco, Tommaso R I Cataldi, Francesco Palmisano
Bacteriochlorophyll a (BChl a), a photosynthetic pigment performing the same functions of chlorophylls in plants, features a bacteriochlorin macrocycle ring (18 π electrons) with two reduced pyrrole rings along with a hydrophobic terpenoid side chain (i.e., the phytol residue). Chlorophylls analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) is not so straightforward since pheophytinization (i.e., release of the central metal ion) and cleavage of the phytol-ester linkage are invariably observed by employing protonating matrices such as 2,5-dihydroxybenzoic acid, sinapinic acid, and α-cyano-4-hydroxycinnamic acid...
October 11, 2016: Journal of the American Society for Mass Spectrometry
Michael Woolman, Alessandra Tata, Emma Bluemke, Delaram Dara, Howard J Ginsberg, Arash Zarrine-Afsar
Mass spectrometry imaging with desorption electrospray ionization mass spectrometry (DESI-MS) is used to characterize cancer from ex vivo slices of tissues. The process is time-consuming. The use of tissue smears for DESI-MS analysis has been proposed as it eliminates the time required to snap-freeze and section the tissue. To assess the utility of tissue smears for rapid cancer characterization, principal component analysis (PCA) was performed to evaluate the concordance between DESI-MS profiles of breast cancer from tissue slices and smears prepared on various surfaces...
October 11, 2016: Journal of the American Society for Mass Spectrometry
Antonino Natalello, Carlo Santambrogio, Rita Grandori
Native mass spectrometry (MS) has become a central tool of structural proteomics, but its applicability to the peculiar class of intrinsically disordered proteins (IDPs) is still object of debate. IDPs lack an ordered tridimensional structure and are characterized by high conformational plasticity. Since they represent valuable targets for cancer and neurodegeneration research, there is an urgent need of methodological advances for description of the conformational ensembles populated by these proteins in solution...
October 11, 2016: Journal of the American Society for Mass Spectrometry
Richard A J O'Hair
No abstract text is available yet for this article.
October 6, 2016: Journal of the American Society for Mass Spectrometry
Wenjing Li, Jianshi Yu, Maureen A Kane
Native mass spectrometry (MS) has become a valuable tool in probing noncovalent protein-ligand interactions in a sample-efficient way, yet the quantitative application potential of native MS has not been fully explored. Cellular retinol binding protein, type I (CrbpI) chaperones retinol and retinal in the cell, protecting them from nonspecific oxidation and delivering them to biosynthesis enzymes where the bound (holo-) and unbound (apo-) forms of CrbpI exert distinct biological functions. Using nanoelectrospray, we developed a native MS assay for probing apo- and holo-CrbpI abundance to facilitate exploring their biological functions in retinoid metabolism and signaling...
October 5, 2016: Journal of the American Society for Mass Spectrometry
Robert Pepin, Erik D Layton, Yang Liu, Carlos Afonso, František Tureček
Electron transfer to doubly and triply charged heptapeptide ions containing polar residues Arg, Lys, and Asp in combination with nonpolar Gly, Ala, and Pro or Leu generates stable and metastable charge-reduced ions, (M + 2H)(+●), in addition to standard electron-transfer dissociation (ETD) fragment ions. The metastable (M + 2H)(+●) ions spontaneously dissociate upon resonant ejection from the linear ion trap, giving irregularly shaped peaks with offset m/z values. The fractions of stable and metastable (M + 2H)(+●) ions and their mass shifts depend on the presence of Pro-4 and Leu-4 residues in the peptides, with the Pro-4 sequences giving larger fractions of the stable ions while showing smaller mass shifts for the metastables...
October 5, 2016: Journal of the American Society for Mass Spectrometry
Andrew J Creese, Helen J Cooper
High field asymmetric waveform ion mobility spectrometry (FAIMS) is well-established as a tool for separating peptide isomers (sequence inversions and post-translationally modified localization variants). Here, we demonstrate the FAIMS is able to differentiate cis and trans isomers of polyproline. Polyproline assumes an all-cis conformation-the PPI helix-in 1-propanol, and an all-trans conformation-the PPII helix-in aqueous solutions. Differentiation of these conformers may be achieved both through use of a cylindrical FAIMS device and a miniaturized ultrahigh field planar FAIMS device...
October 4, 2016: Journal of the American Society for Mass Spectrometry
Anna Maria A P Fernandes, Pedro H Vendramini, Renan Galaverna, Nicolas V Schwab, Luciane C Alberici, Rodinei Augusti, Roger F Castilho, Marcos N Eberlin
Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials...
October 4, 2016: Journal of the American Society for Mass Spectrometry
Inae Jang, Sun Young Lee, Song Hwangbo, Dukjin Kang, Hookeun Lee, Hugh I Kim, Bongjin Moon, Han Bin Oh
The present study demonstrates that one-step peptide backbone fragmentations can be achieved using the TEMPO [2-(2,2,6,6-tetramethyl piperidine-1-oxyl)]-assisted free radical-initiated peptide sequencing (FRIPS) mass spectrometry in a hybrid quadrupole time-of-flight (Q-TOF) mass spectrometer and a Q-Exactive Orbitrap instrument in positive ion mode, in contrast to two-step peptide fragmentation in an ion-trap mass spectrometer (reference Anal. Chem. 85, 7044-7051 (30)). In the hybrid Q-TOF and Q-Exactive instruments, higher collisional energies can be applied to the target peptides, compared with the low collisional energies applied by the ion-trap instrument...
September 29, 2016: Journal of the American Society for Mass Spectrometry
Xixiang Yang, Tomoko Imasaka, Adan Li, Totaro Imasaka
Structural isomers and enantiomers of hexachlorocyclohexane (HCH) were separated using a chiral column by gas chromatography and quantitatively determined by multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (200 and 267 nm) as the ionization source. The order of elution of the enantiomers (i.e., (+)-α-HCH and (-)-α-HCH) was predicted from stabilization energies calculated for the complexes using permethylated γ-cyclodextrin as the stationary phase of the column, and the results were compared with the experimental data...
September 27, 2016: Journal of the American Society for Mass Spectrometry
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