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https://www.readbyqxmd.com/read/28230756/synthesis-and-structural-evaluation-of-organo-ruthenium-complexes-with-%C3%AE-diketonates
#1
Matija Uršič, Tanja Lipec, Anton Meden, Iztok Turel
Four novel ruthenium organometallic complexes: [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)Cl] (1), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)pta]PF₆ (2), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)Cl] (3) and [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)pta]PF₆ (4) were synthesized and characterized by elemental analysis, infrared (IR), UV-Vis, NMR and mass spectroscopy and single-crystal X-ray diffraction...
February 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28225587/compms2miner-an-automatable-metabolite-identification-visualization-and-data-sharing-r-package-for-high-resolution-lc-ms-datasets
#2
William Matthew Bell Edmands, Lauren M Petrick, Dinesh Kumar Barupal, Augustin Scalbert, Mark Wilson, Jeffrey Wickliffe, Stephen M Rappaport
A long-standing challenge of untargeted metabolomic profiling by ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) is efficient transition from unknown mass spectral features to confident metabolite annotations. The compMS2Miner (Comprehensive MS2 Miner) package was developed in the R language to facilitate rapid, comprehensive feature annotation using a peak-picker-output and MS2 data files as inputs. The number of MS2 spectra that can be collected during a metabolomic profiling experiment far outweigh the amount of time required for pain-staking manual interpretation, therefore a degree of software workflow autonomy is required for broad-scale metabolite annotation...
February 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28224912/high-throughput-screening-and-quantitation-of-guanidino-and-ureido-compounds-using-liquid-chromatography-drift-tube-ion-mobility-spectrometry-mass-spectrometry
#3
Ruo-Jing Fan, Fang Zhang, Xiu-Ping Chen, Wan-Shu Qi, Qing Guan, Tuan-Qi Sun, Yin-Long Guo
The present work focused on the high-throughput screening and quantitation of guanidino compounds (GCs) and ureido compounds (UCs) in human thyroid tissues. The strategy employed benzylic rearrangement stable isotope labeling (BRSIL) for the sample preparation and then detection using liquid chromatography-drift tube ion mobility spectrometry-quadrupole time of flight mass spectrometry (LC-DTIMS-QTOF MS). A short reversed-phase LC realized an on-line desalting and a measurement cycle of 5.0 min. DTIMS separation enhanced the better specificity and selectivity for the benzil labeled GCs and UCs...
April 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28223501/biosynthetic-pathway-of-aliphatic-formates-via-a-baeyer-villiger-oxidation-in-mechanism-present-in-astigmatid-mites
#4
Nobuhiro Shimizu, Daisuke Sakata, Eric A Schmelz, Naoki Mori, Yasumasa Kuwahara
Astigmatid mites depend on bioactive glandular secretions, pheromones, and defensive agents to mediate intra- and interspecies interactions. Aliphatic formates, such as (Z,Z)-8,11-heptadecadienyl formate (8,11-F17) and (Z)-8-heptadecenyl formate (8-F17), are rarely encountered natural products that are abundant in Sancassania sp. Sasagawa (Acari: Acaridae) mite secretions. Linoleic acid and oleic acid are predicted as key intermediates in the synthesis of the closely related aliphatic formates. To gain insight in this biosynthetic pathway, acarid mite feeding experiments were conducted using (13)C-labeled precursors to precisely track incorporation...
February 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28221028/characterization-of-an-airborne-laser-spark-ion-source-for-ambient-mass-spectrometry
#5
Andreas Bierstedt, Hendrik Kersten, Reto Glaus, Igor B Gornushkin, Ulrich Panne, Jens Riedel
An airborne laser plasma is suggested as an ambient ion source for mass spectrometry. Its fundamental physical properties, such as an excellent spatial and temporal definition, high electron and ion densities and a high effective cross section in maintaining the plasma, make it a promising candidate for future applications. For deeper insights into the plasma properties, the optical plasma emission is examined and compared to mass spectra. The results show a seemingly contradictory behavior, since the emitted light reports the plasma to almost entirely consist of hot elemental ions, while the corresponding mass spectra exhibit the formation of intact molecular species...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28221024/imet-a-network-based-computational-tool-to-assist-in-the-annotation-of-metabolites-from-tandem-mass-spectra
#6
Antoni Aguilar-Mogas, Marta Sales-Pardo, Miriam Navarro, Roger Guimerà, Oscar Yanes
Structural annotation of metabolites relies mainly on tandem mass spectrometry (MS/MS) analysis. However, approximately 90% of the known metabolites reported in metabolomic databases do not have annotated spectral data from standards. This situation has fostered the development of computational tools that predict fragmentation patterns in silico and compare these to experimental MS/MS spectra. However, because such methods require the molecular structure of the detected compound to be available for the algorithm, the identification of novel metabolites in organisms relevant for biotechnological and medical applications remains a challenge...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28218834/unambiguous-identification-of-serine-and-threonine-pyrophosphorylation-using-neutral-loss-triggered-ethcd-mass-spectrometry
#7
Martin Penkert, Lisa M Yates, Michael Schuemann, David H Perlman, Dorothea Fiedler, Eberhard Krause
Tandem mass spectrometry (MS/MS) has emerged as the core technology for identification of posttranslational modifications (PTMs). Here, we report the mass spectrometry analysis of serine and threonine pyrophosphorylation, a protein modification that has eluded detection by conventional MS/MS methods. Analysis of a set of synthesized, site-specifically modified peptides by different fragmentation techniques shows that pyrophosphorylated peptides exhibit a characteristic neutral loss pattern of 98, 178 and 196 Da, which enables the distinction between isobaric pyro- and diphosphorylated peptides...
February 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28218833/atomic-force-microscopy-thermally-assisted-microsampling-with-atmospheric-pressure-temperature-ramped-thermal-desorption-ionization-mass-spectrometry-analysis
#8
William D Hoffmann, Vilmos Kertesz, Bernadeta R Srijanto, Gary J Van Berkel
The use of atomic force microscopy controlled nanothermal analysis probes for reproducible spatially resolved thermally assisted sampling of micrometer-sized areas (ca. 11 × 17 μm wide × 2.4 μm deep) from relatively low number-average molecular weight (Mn < 3000) polydisperse thin films of poly(2-vinylpyridine) (P2VP) is presented. Following sampling, the nanothermal analysis probes were moved up from the surface and the probe temperature ramped to liberate the sampled materials into the gas phase for atmospheric pressure chemical ionization and mass spectrometric analysis...
February 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28217946/identification-of-four-cornua-by-ultra-performance-liquid-chromatography-with-time-of-flight-mass-spectrometry-coupled-with-principal-component-analysis
#9
Xian-Long Cheng, Qian-Qian Zhang, Ming-Hua Li, Hua Yan, Kun-Zi Yu, Jian-Li Zhou, Li Shao-Ping, Feng Wei, Shuang-Cheng Ma
An ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry method coupled with principal component analysis was developed and applied to the identification of Cornu Antelopis, Cornu Bubali, Cornu Naemorhedi, and Cornu Bovis. The data obtained from the trypsin-digested samples were subjected to principal component analysis to classify these four cornua. Additionally, marker peptides of the cornua were determined by orthogonal partial least-squares discriminant analysis, and fragmentation tandem mass spectra of these marker peptides were evaluated...
February 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28216165/isolation-and-identification-of-new-chemical-constituents-from-chinese-chive-allium-tuberosum-and-toxicological-evaluation-of-raw-and-cooked-chinese-chive
#10
Quan Gao, Xia-Bing Li, Jia Sun, Er-Dong Xia, Feng Tang, Hai-Qun Cao, Hang Xun
Chinese chive (jiu cai) is a popular vegetable in China and has a unique flavour and aroma. The molecular basis of the characteristic fragrance and nutritional properties of Chinese chive has not been previously identified. Sequential extractions in a series of solvents and high-performance liquid chromatography were used to isolate 40 compounds from Chinese chive. The compounds were identified based on high-resolution electrospray ionization mass spectra, 1D and 2D nuclear magnetic resonance techniques, and circular dichroism spectra...
February 16, 2017: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/28215405/screening-of-over-100-drugs-in-horse-urine-using-automated-on-line-solid-phase-extraction-coupled-to-liquid-chromatography-high-resolution-mass-spectrometry-for-doping-control
#11
W H Kwok, Timmy L S Choi, Yeuki Y K Tsoi, Gary N W Leung, Terence S M Wan
A fast method for the direct analysis of enzyme-hydrolysed horse urine using an automated on-line solid-phase extraction (SPE) coupled to a liquid-chromatography/high resolution mass spectrometer was developed. Over 100 drugs of diverse drug classes could be simultaneously detected in horse urine at sub to low parts per billion levels. Urine sample was first hydrolysed by β-glucuronidase to release conjugated drugs, followed by centrifugal filtration. The filtrate (1mL) was directly injected into an on-line SPE system consisting of a pre-column filter and a SPE cartridge column for the separation of analytes from matrix components...
February 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28213728/fourier-transform-ion-cyclotron-resonance-mass-spectrometry-at-the-cyclotron-frequency
#12
Konstantin O Nagornov, Anton N Kozhinov, Yury O Tsybin
The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity...
February 17, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28213143/selective-detection-of-cu-2-and-co-2-in-aqueous-media-asymmetric-chemosensors-crystal-structure-and-spectroscopic-studies
#13
Samira Gholizadeh Dogaheh, Hamid Khanmohammadi, E Carolina Sañudo
Two new azo-azomethine receptors, H2L(1) and H2L(2), containing hydrazine, naphthalene and different electron withdrawing groups, Cl and NO2, have been designed and synthesized for qualitative and quantitative detection of Cu(2+) and Co(2+) in aqueous media. The crystal structure of H2L(1)is reported. The H2L(1)was used as a chemosensor for selective detection of trace amount of Cu(2+) in aqueous media. H2L(2) was also applied to naked-eye distinction of Cu(2+) and Co(2+) from other transition metal ions in aqueous media...
February 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28211480/visualisation-of-abscisic-acid-and-12-oxo-phytodienoic-acid-in-immature-phaseolus-vulgaris-l-seeds-using-desorption-electrospray-ionisation-imaging-mass-spectrometry
#14
Hirofumi Enomoto, Takuya Sensu, Kei Sato, Futoshi Sato, Thanai Paxton, Emi Yumoto, Koji Miyamoto, Masashi Asahina, Takao Yokota, Hisakazu Yamane
The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28210755/assessment-of-quinoxyfen-phototransformation-pathways-by-liquid-chromatography-coupled-to-accurate-mass-spectrometry
#15
Priscila Ferri, María Ramil, Isaac Rodríguez, Rosângela Bergamasco, Angélica Marquetotti Salcedo Vieira, Rafael Cela
Quinoxyfen has been recently identified as a priority hazardous substance in the field of the European water policy. In this work, its fate in aqueous samples and solid supports under UV and solar radiation is investigated. Diverse degradation experiments were carried out, at lab scale, using spiked aliquots of different aqueous matrices (ultrapure, treated wastewater and river water) irradiated at different wavelengths (λ = 254 nm, λ = 365 nm and solar light). Half-lives of quinoxyfen (2-26 min) depended on the wavelength and the intensity of radiation whilst the nature of the aqueous matrix did not play an important role in degradation kinetics...
February 16, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28208272/ion-elevators-and-escalators-in-multilevel-structures-for-lossless-ion-manipulations
#16
Yehia M Ibrahim, Ahmed M Hamid, Jonathan T Cox, Sandilya V B Garimella, Richard D Smith
We describe two approaches based upon ion "elevator" and "escalator" components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations, we designed elevator and escalator components based upon ion current measurements providing essentially lossless transmission in multilevel designs. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28202679/from-molecular-chaperones-to-membrane-motors-through-the-lens-of-a-mass-spectrometrist
#17
REVIEW
Carol V Robinson
Twenty-five years ago, we obtained our first mass spectra of molecular chaperones in complex with protein ligands and entered a new field of gas-phase structural biology. It is perhaps now time to pause and reflect, and to ask how many of our initial structure predictions and models derived from mass spectrometry (MS) datasets were correct. With recent advances in structure determination, many of the most challenging complexes that we studied over the years have become tractable by other structural biology approaches enabling such comparisons to be made...
February 8, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/28199951/a-dioxidovanadium-v-complex-of-nno-donor-schiff-base-as-a-selective-inhibitor-of-protein-tyrosine-phosphatase-1b-synthesis-characterization-and-biological-activities
#18
Yuqi Jia, Liping Lu, Miaoli Zhu, Caixia Yuan, Shu Xing, Xueqi Fu
A new dioxidovanadium (V) complex, VO2(HPPCH) (1) (H2PPCH = N'-picolinoylpyridin-1-ium-2-carbohydrazonate) has been synthesized and characterized by elemental analysis, IR, X-ray diffraction analysis and electrospray ionization mass spectra. Complex 1 crystallized in the monoclinic system with space group P21/c. It potently inhibited PTP1B with IC50 of 0.13 μM, about 7, 15 and 125-fold stronger against PTP1B than over TCPTP, SHP-1 and SHP-2, displaying obvious selectivity against PTP1B. Western blotting analysis indicated that complex 1 effectively increased the phosphorylation of PTP1B substrates, especially the phosphorylation of IR/IGF 1R and IRS-1...
February 6, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28198185/irmpd-spectroscopy-sheds-new-infrared-light-on-the-sulfate-pattern-of-carbohydrates
#19
Baptiste Schindler, Loic Barnes, Christopher John Gray, Stéphane Chambert, Sabine L Flitsch, Jos Oomens, Régis Daniel, Abdul-Rahman Allouche, Isabelle Compagnon
IR spectroscopy of gas phase ions is proposed to resolve positional isomers of sulfated carbohydrates. Mass spectrometric fingerprints and gas phase vibrational spectra in the near and mid IR regions were obtained for sulfated monosaccharides, yielding unambiguous signatures of sulfated isomers. We report the first systematic exploration of the biologically relevant but notoriously challenging deprotonated state in the near IR region. Remarkably, anions displayed very atypical vibrational profiles, which challenge the well-established DFT (Density Functionnal Theory) modeling...
February 15, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28195722/effects-of-relative-humidity-and-particle-phase-water-on-the-heterogeneous-oh-oxidation-of-2-methylglutaric-acid-aqueous-droplets
#20
Man Mei Chim, Chun Yin Chow, James F Davies, ManNin Chan
Organic aerosols can exist as aqueous droplets, with variable water content depending on their composition and environmental conditions (e.g. relative humidity (RH)). Recent laboratory studies have revealed that oxidation kinetics in highly concentrated droplets can be much slower from those in dilute solutions. However, it remains unclear whether particle phase water affects the formation of reaction products physically and/or chemically. In this work, we investigate the role of particle phase water on the heterogeneous chemistry of aqueous organic droplets consisting of 2-methylglutaric acid (2-MGA), measuring the reaction kinetics and the reaction products upon heterogeneous OH oxidation over a range of RH...
February 14, 2017: Journal of Physical Chemistry. A
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