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https://www.readbyqxmd.com/read/28088709/characterization-of-smokeless-powders-using-multiplexed-collision-induced-dissociation-mass-spectrometry-and-chemometric-procedures
#1
Kristen L Reese, A Daniel Jones, Ruth Waddell Smith
This work demonstrates a non-targeted mass spectrometry approach for identification of organic compounds in smokeless powders. Unburned powders were removed from various commercial ammunitions of different brand, primer composition, caliber, and age. The unburned powders and corresponding fired residues were analyzed by liquid chromatography-atmospheric pressure chemical ionization-time-of-flight mass spectrometry (LC-APCI-TOFMS). Multiplexed collision-induced dissociation was performed at increasing collision potentials resulting in successive fragmentation that provided structural information for compound identification in a non-targeted manner...
December 21, 2016: Forensic Science International
https://www.readbyqxmd.com/read/28029296/characterization-of-kewda-volatile-components-by-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#2
Noohi Nasim, Asit Ray, Subhashree Singh, Sudipta Jena, Ambika Sahoo, Basudeba Kar, I Sriram Sandeep, Sujata Mohanty, Sanghamitra Nayak
Kewda (Pandanus fascicularis Lam.) is a well known medicinal and aromatic plant. The paper aims to precisely characterize volatile constituents present in Kewda flower oil using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-TOFMS). A total of 159 components were identified due to enhanced chromatographic separation and mass spectral deconvolution of GCxGC-TOFMS. On the basis of its chemical structure, the identified compounds were grouped into hydrocarbons, alcohols, ethers, ketones, esters, nitrogen compounds, aldehydes, acids, lactones, halides and sulfur containing compounds...
April 2017: Natural Product Research
https://www.readbyqxmd.com/read/28028595/comprehensive-two-dimensional-gas-chromatographic-profiling-and-chemometric-interpretation-of-the-volatile-profiles-of-sweat-in-knit-fabrics
#3
A Paulina de la Mata, Rachel H McQueen, Seo Lin Nam, James J Harynuk
Human axillary sweat is a poorly explored biofluid within the context of metabolomics when compared to other fluids such as blood and urine. In this paper, we explore the volatile organic compounds emitted from two different types of fabric samples (cotton and polyester) which had been worn repeatedly during exercise by participants. Headspace solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) were employed to profile the (semi)volatile compounds on the fabric...
December 27, 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28011407/non-steroidal-anti-inflammatory-drugs-in-the-watercourses-of-elbe-basin-in-czech-republic
#4
Petr Marsik, Jan Rezek, Monika Židková, Barbora Kramulová, Jan Tauchen, Tomáš Vaněk
Non-steroidal anti-inflammatory drugs (NSAIDs) belong to most used pharmaceuticals in the human and veterinary medicine. The widespread consumption of NSAIDs has led to their ubiquitous occurrence in water environment including large river systems. In the present study, concentrations of the five most frequently used NSAIDs (ibuprofen, diclofenac, naproxen, ketoprofen and indomethacin) were determined in the watercourses of the river Elbe basin in Czech Republic. The presence of the pharmaceuticals was measured at 29 sampling sites including urban and rural areas, small creeks and main tributaries of the Elbe monthly from April to December of 2011...
December 14, 2016: Chemosphere
https://www.readbyqxmd.com/read/28007176/potential-of-capillary-electrophoresis-mass-spectrometry-for-the-characterization-and-monitoring-of-amine-derivatized-naphthenic-acids-from-oil-sands-process-affected-water
#5
Matthew S MacLennan, Cai Tie, Kevin Kovalchik, Kerry M Peru, Xinxiang Zhang, John V Headley, David D Y Chen
Capillary electrophoresis coupled to mass spectrometry (CE-MS) was used for the analysis of naphthenic acid fraction compounds (NAFCs) of oil sands process-affected water (OSPW). A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE-MS in less than 15min. Time of flight MS analysis (TOFMS), optimized for high molecular weight ions, showed NAFCs between 250 and 800m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs (between 100 and 450m/z) are visible under our experimental conditions...
November 2016: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/27999311/metabolomic-approaches-to-explore-chemical-diversity-of-human-breast-milk-formula-milk-and-bovine-milk
#6
Linxi Qian, Aihua Zhao, Yinan Zhang, Tianlu Chen, Steven H Zeisel, Wei Jia, Wei Cai
Although many studies have been conducted on the components present in human breast milk (HM), research on the differences of chemical metabolites between HM, bovine milk (BM) and formula milk (FM) is limited. This study was to explore the chemical diversity of HM, BM and FM by metabolomic approaches. GC-TOFMS and UPLC-QTOFMS were applied to investigate the metabolic compositions in 30 HM samples, 20 FM samples and 20 BM samples. Metabolite profiling identified that most of the non-esterified fatty acids, which reflected the hydrolysis of triglycerides, were much more abundant in HM than those in FM and BM, except for palmitic acid and stearic acid...
December 17, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27987862/structural-features-and-anticancer-activity-in-vitro-of-fucoidan-derivatives-from-brown-alga-saccharina-cichorioides
#7
Stanislav D Anastyuk, Natalia M Shevchenko, Roza V Usoltseva Menshova, Artyom S Silchenko, Pavel A Zadorozhny, Pavel S Dmitrenok, Svetlana P Ermakova
A fucoidan ScF from brown alga Saccharina cichorioides was extracted, purified and partially depolymerized by autohydrolysis at 37°C for 24, 48 and 72h. Supernatant (SN) and pellet (PL) fractions were obtained by ethanol precipitation of each sample. Unlike spectral data of ScF, NMR of PL derivatives clearly suggested the structure: 1,3-linked α-l-Fucp-4-OSO3(-) repeating unit. Molecular weights (MWs) of PL fractions were 30, 26 and 18kDa for 24, 48 and 72h of autohydrolyis, respectively. MALDI-TOFMS, size-exclusion HPLC and carbohydrate polyacrylamide-gel electrophoresis (C-PAGE) indicated a similarity of SN mixtures...
February 10, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/27976851/three-dimensional-elemental-imaging-of-nantan-meteorite-via-femtosecond-laser-ionization-time-of-flight-mass-spectrometry
#8
Miaohong He, Yifan Meng, Shanshan Yan, Wei Hang, Wenge Zhou, Benli Huang
Femtosecond laser ionization time-of-flight mass spectrometry (fs-LI-TOFMS) is introduced for the three-dimensional elemental analysis of a Nantan meteorite. Spatially resolved multielemental imaging of major and minor compositions in a meteorite are presented with a lateral resolution of 50 μm and a depth resolution of 7 μm. Distinct 3D distributions of siderophile, lithophile, and chalcophile elements are revealed. Co and Ni are highly siderophile (Iron-loving), mainly enriched in the metal phase. Cr, Cu, V, and Mn are enriched in the sulfide for their chalcophile (S-loving) tendency...
December 15, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27934237/highly-selective-screening-of-estrogenic-compounds-in-consumer-electronics-plastics-by-liquid-chromatography-in-parallel-combined-with-nanofractionation-bioactivity-detection-and-mass-spectrometry
#9
Willem Jonker, Ana Ballesteros-Gómez, Timo Hamers, Govert W Somsen, Marja H Lamoree, Jeroen Kool
The chemical safety of consumer products is an issue of emerging concern. Plastics are widely used, e.g. as casings of consumer electronics (TVs, computers, routers, etc.), which are present in houses and offices in continuously increasing numbers. In this study, we investigate the estrogenic activity of components of plastics coming from electronics' casings. A recently developed fractionation platform for effect-directed analysis (EDA) was used. This platform combines reversed-phase liquid chromatography in parallel with bioassay detection via nanofractionation and with online high-resolution time-of-flight mass spectrometry (TOFMS) for the identification of bioactives...
November 15, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27930839/expanding-the-klebsiella-pneumoniae-volatile-metabolome-using-advanced-analytical-instrumentation-for-the-detection-of-novel-metabolites
#10
Christiaan A Rees, Flavio A Franchina, Katherine V Nordick, Paul J Kim, Jane E Hill
AIMS: The purpose of this study was to identify the volatile molecules produced by the pathogenic Gram-negative bacterium Klebsiella pneumoniae (ATCC 13883) during in vitro growth using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). METHODS AND RESULTS: K. pneumoniae ATCC 13883 was incubated in lysogeny broth (LB) to mid-exponential and stationary growth phases. Headspace volatile molecules from culture supernatants were concentrated using solid-phase microextraction (SPME) and analyzed via GC×GC-TOFMS...
December 8, 2016: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/27914609/determination-of-diamondoids-in-crude-oils-using-gas-purge-microsyringe-extraction-with-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#11
Wanfeng Zhang, Shukui Zhu, Liling Pang, Xuanbo Gao, Gang-Tian Zhu, Donghao Li
Based on a homemade device, gas purge microsyringe extraction (GP-MSE) of crude oil samples was developed for the first time. As a simple, fast, low-cost, sensitive and solvent-saving technique, GP-MSE provides some outstanding advantages over the widely used sample preparation methods for crude oils such as column chromatography (ASTM D2549). Several parameters affecting extraction efficiency were optimized, including extraction temperature, extraction time, extraction solvent, condensing temperature and purge gas flow rate...
December 23, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27912967/qualitative-analysis-of-copaifera-oleoresin-using-comprehensive-two-dimensional-gas-chromatography-and-gas-chromatography-with-classical-and-cold-electron-ionisation-mass-spectrometry
#12
Yong Foo Wong, Thais M Uekane, Claudia M Rezende, Humberto R Bizzo, Philip J Marriott
Improved separation of both sesquiterpenes and diterpenic acids in Copaifera multijuga Hayne oleoresin, is demonstrated by using comprehensive two-dimensional gas chromatography (GC×GC) coupled to accurate mass time-of-flight mass spectrometry (accTOFMS). GC×GC separation employs polar phases (including ionic liquid phases) as the first dimension ((1)D) column, combined with a lower polarity (2)D phase. Elution temperatures (Te) of diterpenic acids (in methyl ester form, DAME) increased as the (1)D McReynolds' polarity value of the column phase decreased...
December 16, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27900858/rapid-identification-of-triphenylmethane-dyes-by-ion-mobility-time-of-flight-mass-spectrometry
#13
Alexey A Sysoev, Sergey S Poteshin, Denis M Chernyshev, Alexander A Sysoev
An ion mobility time-of-flight mass spectrometry (IM-TOFMS)-based method has been preliminarily investigated for the identification of triphenylmethane ballpoint pen dyes on paper. The dyes were sampled from one-year-old ballpoint pen ink entries. The entries were written on paper documents stored in the dark in a bookcase. Sample solutions were prepared by extraction of dyes in a vial. Basic violet 2, Methyl violet 6B, Methyl violet 2B and Crystal violet were characterized by IM-TOFMS. Since the ballpoint ink dyes contain ionic compounds, the studied compounds were expected to form stable peaks in the atmospheric pressure drift tube ion mobility spectrometry, and this was experimentally verified...
2016: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/27869104/comparative-analysis-of-the-volatile-metabolomes-of-pseudomonas-aeruginosa-clinical-isolates
#14
Heather D Bean, Christiaan A Rees, Jane E Hill
Pseudomonas aeruginosa is a nearly ubiquitous Gram-negative organism, well known to occupy a multitude of environmental niches and cause human infections at a variety of bodily sites, due to its metabolic flexibility, secondary to extensive genetic heterogeneity at the species level. Because of its dynamic metabolism and clinical importance, we sought to perform a comparative analysis on the volatile metabolome (the 'volatilome') produced by P. aeruginosa clinical isolates. In this study, we analyzed the headspace volatile molecules of 24 P...
November 21, 2016: Journal of Breath Research
https://www.readbyqxmd.com/read/27855313/characterization-of-the-clostridium-difficile-volatile-metabolome-using-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#15
Christiaan A Rees, Aimee Shen, Jane E Hill
Clostridium difficile is a bacterial pathogen capable of causing life-threatening infections of the gastrointestinal tract characterized by severe diarrhea. Exposure to certain classes of antibiotics, advanced age, and prolonged hospitalizations are known risk factors for infection by this organism. Anecdotally, healthcare providers have reported that they can smell C. difficile infections in their patients, and several studies have suggested that there may indeed be an olfactory signal associated with C. difficile-associated diarrhea...
December 15, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/27812583/the-modulatory-effect-of-infusions-of-green-tea-oolong-tea-and-black-tea-on-gut-microbiota-in-high-fat-induced-obese-mice
#16
Zhibin Liu, Zhichao Chen, Hongwen Guo, Dongping He, Huiru Zhao, Zhiyao Wang, Wen Zhang, Lan Liao, Chen Zhang, Li Ni
Tea consumption has been identified to have an anti-obesity effect. Whether it is associated with gut microbiota modulation is investigated in this study. Phenolic profiles of infusions of green tea, oolong tea and black tea were comprehensively compared first, by utilizing ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOFMS). Subsequently, high-fat-diet induced obese C57BL/6J mice were orally administered these three types of tea infusions for 13 weeks to evaluate their anti-obesity and gut microbiota modulatory effects...
December 7, 2016: Food & Function
https://www.readbyqxmd.com/read/27788432/hydrothermal-liquefaction-of-cyanidioschyzon-merolae-and-the-influence-of-catalysts-on-products
#17
Tapaswy Muppaneni, Harvind K Reddy, Thinesh Selvaratnam, Kodanda Phani Raj Dandamudi, Barry Dungan, Nagamany Nirmalakhandan, Tanner Schaub, F Omar Holguin, Wayne Voorhies, Peter Lammers, Shuguang Deng
This work investigates the hydrothermal liquefaction (HTL) of Cyanidioschyzon merolae algal species under various reaction temperatures and catalysts. Liquefaction of microalgae was performed with 10% solid loading for 30min at temperatures of 180-300°C to study the influences of two base and two acid catalysts on HTL product fractions. Maximum biocrude oil yield of 16.98% was obtained at 300°C with no catalyst. The biocrude oil yield increased to 22.67% when KOH was introduced into the reaction mixture as a catalyst...
January 2017: Bioresource Technology
https://www.readbyqxmd.com/read/27769467/online-monitoring-of-trace-chlorinated-benzenes-in-flue-gas-of-municipal-solid-waste-incinerator-by-windowless-vuv-lamp-single-photon-ionization-tofms-coupled-with-automatic-enrichment-system
#18
Wei Liu, Jichun Jiang, Keyong Hou, Weiguo Wang, Yachen Qi, Yan Wang, Yuanyuan Xie, Lei Hua, Haiyang Li
Chlorinated benzenes are typical precursors and indicators for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emissions from waste incinerators. Online and real-time monitoring of chlorobenzenes is a challenge due to their low concentration and complex nature of the flue gas. In this work, a continuous online monitoring system was built for detection of trace chlorinated benzenes based on a time-of-flight mass spectrometer (TOFMS). A single photon ionization (SPI) source based on a radiofrequency-excited windowless vacuum ultraviolet (VUV) lamp was developed for the first time to eliminate the signal attenuation resulting from the contamination of magnesium fluoride windows and to avoid the fragment ions...
December 1, 2016: Talanta
https://www.readbyqxmd.com/read/27769464/high-temperature-diaphragm-valve-based-comprehensive-two-dimensional-gas-chromatography-with-time-of-flight-mass-spectrometry
#19
Chris E Freye, Robert E Synovec
A high temperature diaphragm valve-based two-dimensional (2D) gas chromatography (GC×GC) with time-of-flight mass spectrometry (TOFMS) instrument, with the valve mounted directly in the GC oven, is demonstrated with separations up to 325°C. Use of the diaphragm valve allowed for the use of uncoupled carrier gas flows for (1)D (first column dimension) and (2)D (second column dimension), with a (1)D flow rate of 1ml/min, and a (2)D flow rate 3ml/min. The 3ml/min flow rate on (2)D was selected to ensure compatibility with most TOFMS detectors...
December 1, 2016: Talanta
https://www.readbyqxmd.com/read/27744102/a-metabolomics-investigation-of-the-function-of-the-esx-1-gene-cluster-in-mycobacteria
#20
Du Toit Loots, Conrad C Swanepoel, Mae Newton-Foot, Nicolaas C Gey van Pittius
The ESX-1 gene cluster, encoding the Type-VII secretion (T7S) system and its virulence associated proteins, ESAT-6 and CFP-10, is thought to be responsible for the transport of extracellular proteins across the hydrophobic and highly impermeable, cell envelope of Mycobacterium, and is involved in virulence in Mycobacterium tuberculosis, the causative agent of tuberculosis. Using a GCxGC-TOFMS metabolomics approach, a M. smegmatis ESX-1 knock-out strain (ΔESX-1ms) was compared to that of the M. smegmatis wild-type parent strain, and the metabolite markers due to the presence or absence of the ESX-1 gene cluster were identified...
November 2016: Microbial Pathogenesis
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