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Journal of the American Society for Mass Spectrometry

Vaishnavi Rajagopal, Chris Stokes, Alessandra Ferzoco
We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields...
August 18, 2017: Journal of the American Society for Mass Spectrometry
Makoto Kihara, Yukari Matsuo-Tezuka, Mariko Noguchi-Sasaki, Keigo Yorozu, Mitsue Kurasawa, Yasushi Shimonaka, Michinori Hirata
Epoetin beta pegol (continuous erythropoiesis receptor activator; C.E.R.A.), or methoxy-polyethylene glycol-modified epoetin beta, is a long-acting erythropoiesis stimulating agent (ESA) that effectively maintains hemoglobin levels. It promotes proliferation of erythroid progenitor cells in hematopoietic organs and leads to increased reticulocyte and hemoglobin levels. However, the detailed erythropoietic effects of various ESAs on their target organs have yet to be clarified, and new approaches are needed to analyze tissue iron localization with structural information...
August 17, 2017: Journal of the American Society for Mass Spectrometry
Yan Hong, Sheng Liu, Chaoqun Huang, Lei Xia, Chengyin Shen, Haihe Jiang, Yannan Chu
In order to improve the resolving power (RP) and signal-to-noise ratio (SNR) of ion mobility spectrometry (IMS) simultaneously, a modified Hadamard transform-inverse ion mobility spectrometry (MHT-IIMS) technique was developed. In this novel technique, a series of isolating codes were appended to each element of the pseudo random binary sequence (PRBS), and then the modified modulation sequence was formed and used to control the ion gate of the inverse IMS (IIMS). Experimental results demonstrate that the MHT-IIMS technique can significantly enhance the resolving power and SNR simultaneously by measuring the spectra of reaction ions...
August 17, 2017: Journal of the American Society for Mass Spectrometry
Jean R N Haler, Johann Far, Abdelhafid Aqil, Jan Claereboudt, Nick Tomczyk, Kevin Giles, Christine Jérôme, Edwin De Pauw
Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped,…). Electrospray coupled to IM-MS already revealed the coexistence of several charge state-dependent conformations for a single charge state of biomolecules with strong intramolecular interactions, even when limited resolving power IM-MS instruments were used. For synthetic polymers, the sample's polydispersity allows the observation of several chain lengths...
August 14, 2017: Journal of the American Society for Mass Spectrometry
Olga Gorlova, Sean M Colvin, Antonio Brathwaite, Fabian S Menges, Stephanie M Craig, Scott J Miller, Mark A Johnson
Recent advances in the coupling of vibrational spectroscopy with mass spectrometry create new opportunities for the structural characterization of metabolites with great sensitivity. Previous studies have demonstrated this scheme on 300 K ions using very high power free electron lasers in the fingerprint region of the infrared. Here we extend the scope of this approach to a single investigator scale as well as extend the spectral range to include the OH stretching fundamentals. This is accomplished by detecting the IR absorptions in a linear action regime by photodissociation of weakly bound N2 molecules, which are attached to the target ions in a cryogenically cooled, rf ion trap...
August 11, 2017: Journal of the American Society for Mass Spectrometry
Myong In Oh, Styliani Consta
We study systematically the charging and release mechanisms of a flexible macromolecule, modeled by poly(ethylene glycol) (PEG), in a droplet by using molecular dynamics simulations. We compare how PEG is solvated and charged by sodium Na(+) ions in a droplet of water (H2O), acetonitrile (MeCN), and their mixtures. Initially, we examine the location and the conformation of the macromolecule in a droplet bearing no net charge. It is revealed that the presence of charge carriers do not affect the location of PEG in aqueous and MeCN droplets compared with that in the neutral droplets, but the location of the macromolecule and the droplet size do affect the PEG conformation...
August 11, 2017: Journal of the American Society for Mass Spectrometry
Bryn Flinders, Emma Beasley, Ricky M Verlaan, Eva Cuypers, Simona Francese, Tom Bassindale, Malcolm R Clench, Ron M A Heeren
Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) has been employed to rapidly screen longitudinally sectioned drug user hair samples for cocaine and its metabolites using continuous raster imaging. Optimization of the spatial resolution and raster speed were performed on intact cocaine contaminated hair samples. The optimized settings (100 × 150 μm at 0.24 mm/s) were subsequently used to examine longitudinally sectioned drug user hair samples. The MALDI-MS/MS images showed the distribution of the most abundant cocaine product ion at m/z 182...
August 11, 2017: Journal of the American Society for Mass Spectrometry
Michael S Gardner, Lisa G McWilliams, Jeffrey I Jones, Zsuzsanna Kuklenyik, James L Pirkle, John R Barr
We demonstrate the application of in-source nitrogen collision-induced dissociation (CID) that eliminates the need for ester hydrolysis before simultaneous analysis of esterified cholesterol (EC) and triglycerides (TG) along with free cholesterol (FC) from human serum, using normal phase liquid chromatography (LC) coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). The analysis requires only 50 μL of 1:100 dilute serum with a high-throughput, precipitation/evaporation/extraction protocol in one pot...
August 11, 2017: Journal of the American Society for Mass Spectrometry
Anastasia S Kondrateva, Maxim V Mishin, Sergey E Alexandrov
NiO layers were deposited by metal-organic chemical vapor deposition using bis-(ethylcyclopentadienyl) nickel (EtCp)2Ni and oxygen or ozone. As a continuation of kinetic study of NiO MOCVD the gas-phase, transformations of (EtCp)2Ni were studied in the temperature range of 380-830 K. Time of reactions corresponding to the residence time of the gas stream in hot zone of the reactor was about 0.1 s under conditions studied. The interaction of (EtCp)2Ni with oxygen started at 450 K and its conversion rate reached the maximum at 700 K...
August 11, 2017: Journal of the American Society for Mass Spectrometry
Daniel S Ziemianowicz, Ryan Bomgarden, Chris Etienne, David C Schriemer
Mapping proteins with chemical reagents and mass spectrometry can generate a measure of accessible surface area, which in turn can be used to support the modeling and refinement of protein structures. Photolytically generated carbenes are a promising class of reagent for this purpose. Substituent effects appear to influence surface mapping properties, allowing for a useful measure of design control. However, to use carbene labeling data in a quantitative manner for modeling activities, we require a better understanding of their inherent amino acid reactivity, so that incorporation data can be normalized...
August 10, 2017: Journal of the American Society for Mass Spectrometry
Pengfei Li, Iris Kreft, Glen P Jackson
Top-down analyses of protonated insulin cations of charge states of 4+, 5+, or 6+ were performed by exposing the isolated precursor ions to a beam of helium cations with kinetic energy of more than 6 keV, in a technique termed charge transfer dissociation (CTD). The ~100 ms charge transfer reaction resulted in approximately 20% conversion efficiency to other intact charge exchange products (CTnoD), and a range of low abundance fragment ions. To increase backbone and sulfide cleavages, and to provide better structural information than straightforward MS(2) CTD, the CTnoD oxidized products were isolated and subjected to collisional activation at the MS(3) level...
August 7, 2017: Journal of the American Society for Mass Spectrometry
Lilian V Tose, Michael Murgu, Boniek G Vaz, Wanderson Romão
Atmospheric solids analysis probe mass spectrometry (ASAP-MS) is a powerful tool for analysis of solid and liquid samples. It is an excellent alternative for crude oil analysis without any sample preparation step. Here, ASAP-MS in positive ion mode, ASAP(+)-MS, has been optimized for analysis of condensed aromatics (CA) standards, crude oil, and paraffinic fraction samples using a Synapt G2-S HDMS. Initially, two methodologies were used to access the chemical composition of samples: (1) using a temperature gradient varying from 150 to 600 °C at a heating rate of 150 °C min(-1), and (2) with constant temperature of 300 and 400 °C...
August 7, 2017: Journal of the American Society for Mass Spectrometry
Pengyu Hong, Hui Sun, Long Sha, Yi Pu, Kshitij Khatri, Xiang Yu, Yang Tang, Cheng Lin
A major challenge in glycomics is the characterization of complex glycan structures that are essential for understanding their diverse roles in many biological processes. We present a novel efficient computational approach, named GlycoDeNovo, for accurate elucidation of the glycan topologies from their tandem mass spectra. Given a spectrum, GlycoDeNovo first builds an interpretation-graph specifying how to interpret each peak using preceding interpreted peaks. It then reconstructs the topologies of peaks that contribute to interpreting the precursor ion...
August 7, 2017: Journal of the American Society for Mass Spectrometry
Jiying Pei, Cheng-Chih Hsu, Ruijie Zhang, Yinghui Wang, Kefu Yu, Guangming Huang
Unexpected reduction of iminoquinone (IQ) and quinone derivatives was first reported during positive electrospray ionization mass spectrometry. Upon increasing spray voltage, the intensities of IQ and quinone derivatives decreased drastically, accompanying the increase of the intensities of the reduction products, amodiaquine (AQ) and phenol derivatives. To gain more insight into the mechanism of such reduction, we explored the experimental factors that are influential to corona discharge (CD). The results show that experimental parameters that favor severe CD, including metal spray emitter, using water as spray solvent, sheath gas with low dielectric strength (e...
August 7, 2017: Journal of the American Society for Mass Spectrometry
Wei Zheng, Fangxu Wang, Yang Zhao, Xinguang Sun, Liping Kang, Ziquan Fan, Lirui Qiao, Renyi Yan, Shuchen Liu, Baiping Ma
A strategy for rapid identification of the chemical constituents from crude extracts of Tribulus terrestris was proposed using an informatics platform for the UHPLC/Q-TOF MS(E) data analyses. This strategy mainly utilizes neutral losses, characteristic fragments, and in-house library to rapidly identify the structure of the compounds. With this strategy, rapid characterization of the chemical components of T. terrestris from Beijing, China was successfully achieved. A total of 82 steroidal saponins and nine flavonoids were identified or tentatively identified from T...
August 1, 2017: Journal of the American Society for Mass Spectrometry
Quentin Duez, Fabien Chirot, Romain Liénard, Thomas Josse, ChangMin Choi, Olivier Coulembier, Philippe Dugourd, Jérôme Cornil, Pascal Gerbaux, Julien De Winter
One of the main issues when using traveling wave ion mobility spectrometry (TWIMS) for the determination of collisional cross-section (CCS) concerns the need for a robust calibration procedure built from referent ions of known CCS. Here, we implement synthetic polymer ions as CCS calibrants in positive ion mode. Based on their intrinsic polydispersities, polymers offer in a single sample the opportunity to generate, upon electrospray ionization, numerous ions covering a broad mass range and a large CCS window for different charge states at a time...
July 31, 2017: Journal of the American Society for Mass Spectrometry
Maria A A Rodrigues, Débora C Mendes, Vaidhyanathan Ramamurthy, José P Da Silva
Electrospray ionization mass spectrometry (ESI-MS) is a powerful tool to study host-guest supramolecular interactions. ESI-MS can be used for detailed gas-phase reactivity studies, to clarify the structure, or simply to verify the formation of complexes. Depending on the structure of the host and of the guest, negative and/or positive ESI are used. Here we report the unexpected formation of host-guest complexes between cucurbit[n]urils (n = 7, 8, CB[n]) and amine, styryl pyridine, and styryl pyridine dimer cations, under negative ESI...
July 29, 2017: Journal of the American Society for Mass Spectrometry
Mathilde Bouakil, Alexander Kulesza, Steven Daly, Luke MacAleese, Rodolphe Antoine, Philippe Dugourd
The visible photodissociation mechanisms of QSY7-tagged peptides of increasing size have been investigated by coupling a mass spectrometer and an optical parametric oscillator laser beam. The experiments herein consist of energy resolved collision- and laser-induced dissociation measurements on the chromophore-tagged peptides. The results show that fragmentation occurs by similar channels in both activation methods, but that the branching ratios are vastly different. Observation of a size-dependent minimum laser pulse energy required to induce fragmentation, and collisional cooling rates in time resolved experiments show that laser-induced dissociation occurs through the absorption of multiple photons by the chromophore and the subsequent heating through vibrational energy redistribution...
July 28, 2017: Journal of the American Society for Mass Spectrometry
Jiang Zhang, Rachel R Ogorzalek Loo, Joseph A Loo
Native mass spectrometry (MS) with electrospray ionization (ESI) has evolved as an invaluable tool for the characterization of intact native proteins and non-covalently bound protein complexes. Here we report the structural characterization by high resolution native top-down MS of human thrombin and its complex with the Bock thrombin binding aptamer (TBA), a 15-nucleotide DNA with high specificity and affinity for thrombin. Accurate mass measurements revealed that the predominant form of native human α-thrombin contains a glycosylation mass of 2205 Da, corresponding to a sialylated symmetric biantennary oligosaccharide structure without fucosylation...
July 28, 2017: Journal of the American Society for Mass Spectrometry
Son N Nguyen, Ryan L Sontag, James P Carson, Richard A Corley, Charles Ansong, Julia Laskin
Constant mode ambient mass spectrometry imaging (MSI) of tissue sections with high lateral resolution of better than 10 μm was performed by combining shear force microscopy with nanospray desorption electrospray ionization (nano-DESI). Shear force microscopy enabled precise control of the distance between the sample and nano-DESI probe during MSI experiments and provided information on sample topography. Proof-of-concept experiments were performed using lung and brain tissue sections representing spongy and dense tissues, respectively...
July 28, 2017: Journal of the American Society for Mass Spectrometry
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