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https://www.readbyqxmd.com/read/29146315/sensory-olfactometry-and-comprehensive-two-dimensional-gas-chromatography-analyses-as-appropriate-tools-to-characterize-the-effects-of-vine-management-on-wine-aroma
#1
Karine P Nicolli, Aline C T Biasoto, Érica A Souza-Silva, Celito C Guerra, Henrique P Dos Santos, Juliane E Welke, Cláudia A Zini
For the first time, the influence of different vine management was evaluated in relation to volatile profile and sensory perception through GC×GC/TOFMS, QDA, GC-FID, GC/MS, and GC-O. GC×GC/TOFMS analyses and QDA have shown that a larger spacing between vine rows (2 rather than 1m), attachment of shoots upwards, and irrigation did not result in wine improvement. Conversely, wines elaborated with grapes from a vine with a lower bud load (20 per plant; sample M1) stood out among the other procedures, rendering the most promising wine aroma...
March 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29126478/optimization-of-gc-tof-ms-analysis-conditions-for-assessing-host-gut-microbiota-metabolic-interactions-chinese-rhubarb-alters-fecal-aromatic-amino-acids-and-phenol-metabolism
#2
Shan Yin, Pan Guo, Dafu Hai, Li Xu, Jiale Shu, Wenjin Zhang, Muhammad Idrees Khan, Irwin J Kurland, Yunping Qiu, Yumin Liu
In this paper, an optimized method based on gas chromatography/time-of-flight mass spectrometry (GC-TOFMS) platform has been developed for the analysis of gut microbial-host related co-metabolites in fecal samples. The optimization was performed with proportion of chloroform (C), methanol (M) and water (W) for the extraction of specific metabolic pathways of interest. Loading Bi-plots from the PLS regression model revealed that high concentration of chloroform emphasized the extraction of short chain fatty acids and TCA intermediates, while the higher concentration of methanol emphasized indole and phenyl derivatives...
December 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29067456/effects-of-shu-gan-jian-pi-formula-on-rats-with-carbon-tetrachloride%C3%A2-induced-liver-fibrosis-using-serum-metabonomics-based-on-gas-chromatography%C3%A2-time-of-flight-mass-spectrometry
#3
Hui Jiang, Xiu-Juan Qin, Wei-Ping Li, Rong Ma, Ting Wang, Zhu-Qing Li
Liver fibrosis is a common stage in the majority of chronic liver diseases, regardless of the etiology, and its progression may lead to hepatic cirrhosis or hepatocellular carcinoma. Metabolomics, a powerful approach in systems biology, is a discipline used to qualitatively and quantitatively analyze the small molecule metabolites of cells at specific times and under certain conditions. The present study aimed to investigate serum metabolic changes following Shu Gan Jian Pi formula (SGJPF) treatment of carbon tetrachloride (CCl4)‑induced liver fibrosis in rats using gas chromatography‑time of flight mass spectrometry (GC‑TOFMS)...
October 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/29055977/roasting-pumpkin-seeds-and-changes-in-the-composition-and-oxidative-stability-of-cold-pressed-oils
#4
Marianna Raczyk, Aleksander Siger, Elżbieta Radziejewska-Kubzdela, Katarzyna Ratusz, Magdalena Rudzińska
BACKGROUND: Pumpkin seed oil is valuable oil for its distinctive taste and aroma, as well as supposed health- promoting properties. The aim of this study was to investigate how roasting pumpkin seeds influences the physicochemical properties of cold-pressed oils. METHODS: The fatty acid composition, content of phytosterols, carotenoids and tocopherols, oxidative stability and colour were determined in oils after cold pressing and storage for 3 months using GC-FID, GCxGC-ToFMS, HPLC, Rancimat and spectrophotometric methods...
July 2017: Acta Scientiarum Polonorum. Technologia Alimentaria
https://www.readbyqxmd.com/read/29030031/thermal-desorption-comprehensive-two-dimensional-gas-chromatography-coupled-to-time-of-flight-mass-spectrometry-for-vapour-phase-mainstream-tobacco-smoke-analysis
#5
Benjamin Savareear, Michał Brokl, Chris Wright, Jean-Francois Focant
A thermal desorption comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (TD-GC×GC-TOFMS) method has been developed for the analysis of mainstream tobacco smoke (MTS) vapour phase (VP). The selection process of the sample introduction approach involved comparing the results obtained from three different approaches: a) use of gas sampling bag followed by SPME (Tedlar(®)-SPME), b) gas sampling bag followed by TD (Tedlar(®)-TD), and c) sampling directly on TD sorbents (Direct-TD)...
October 6, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28960066/direct-infusion-resonance-enhanced-multiphoton-ionization-mass-spectrometry-of-liquid-samples-under-vacuum-conditions
#6
Claudia Kruth, Hendryk Czech, Martin Sklorz, Johannes Passig, Sven Ehlert, Achille Cappiello, Ralf Zimmermann
Direct infusion resonance-enhanced multiphoton ionization (DI-REMPI) was performed on liquid samples, which were introduced to the ion source via a direct liquid interface, to enable the investigation of dissolved aromatic compounds. Desolvation and nebulization of the samples were supported by a heated repeller using flow rates in the upper nL min(-1) range. The obtained mass spectra of five pure polycyclic aromatic hydrocarbons as well as complex petroleum samples revealed predominantly molecular ions without evidence of solvent or dopant effects as observed in atmospheric pressure photoionization (APPI) and laser ionization (APLI) with limits of detection in the lower pmol range...
September 29, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28956925/flash-pyrolysis-of-t-butyl-hydroperoxide-and-di-t-butyl-peroxide-evidence-of-roaming-in-the-decomposition-of-organic-hydroperoxides
#7
Paul J Jones, Blake Riser, Jingsong Zhang
Thermal decomposition of t-butyl hydroperoxide and di-t-butyl peroxide was investigated using flash pyrolysis (in a short reaction time of <100 μs) and vacuum-ultraviolet (λ = 118.2 nm) single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) at temperatures up to 1120 K and quantum computational methods. Acetone and methyl radical were detected as the predominant products in the initial decomposition of di-t-butyl peroxide via O-O bond fission. In the initial dissociation of t-butyl hydroperoxide, acetone, methyl radical, isobutylene, and isobutylene oxide products were identified...
October 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28952968/comprehensive-volatile-metabolic-fingerprinting-of-bacterial-and-fungal-pathogen-groups
#8
Christiaan Rees, Alison Burklund, Pierre-Hugues Stefanuto, Joseph D Schwartzman, Jane E Hill
The identification of pathogen-specific volatile metabolic "fingerprints" could lead to the rapid identification of disease-causing organisms either directly from <i>ex vivo</i> patient bio-specimens or from <i>in vitro</i> cultures. In the present study, we have evaluated the volatile metabolites produced by 100 clinical isolates belonging to ten distinct pathogen groups that, in aggregate, account for 90 % of bloodstream infections, 90 % of urinary tract infections, and 80 % of infections encountered in the intensive care unit setting...
September 27, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28944977/characterization-of-dicarboxylic-naphthenic-acid-fraction-compounds-utilizing-amide-derivatization-proof-of-concept
#9
Kevin A Kovalchik, Matthew S MacLennan, Kerry M Peru, Chukwuemeka Ajaero, Dena W McMartin, John V Headley, David D Y Chen
RATIONALE: The characterization of naphthenic acid fraction compounds (NAFCs) in oil sands process affected water (OSPW) is of interest for both toxicology studies and regulatory reasons. Previous studies utilizing authentic standards have identified dicarboxylic naphthenic acids using two-dimensional gas chromatography hyphenated to time-of-flight mass spectrometry (GCxGC/TOFMS). The selective derivatization of hydroxyl groups has also recently aided in the characterization of oxy-NAFCs, and indirectly the characterization of dicarboxylic NAFCs...
September 25, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28940243/novel-contaminants-identified-in-fish-kills-in-the-red-river-watershed-2011-2013
#10
Tammy L Jones-Lepp, Vince Taguchi, Wayne Sovocool, Don Betowski, Patrick DeArmond, Brian Schumacher, Witold Winnik, Rick McMillin, Chris Armstrong
Provisional molecular weights and chemical formulas were assigned to 4 significant previously unidentified contaminants present during active fish kills in the Red River region of Oklahoma. The provisional identifications of these contaminants were determined using high-resolution liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS), LC-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICRMS), and LC-ion trap mass spectrometry (LC-ITMS). Environmental water samples were extracted using a solid-phase extraction (SPE) method, and sediment samples were extracted using a modified sonication liquid extraction method...
September 21, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28937250/role-of-exercise-induced-calmodulin-protein-kinase-camk-ii-activation-in-the-regulation-of-omega-6-fatty-acids-and-lipid-metabolism-genes-in-rat-skeletal-muscle
#11
J S Joseph, A O Ayeleso, E Mukwevho
Activation of calmodulin dependent protein kinase (CaMK)II by exercise is beneficial in controlling membrane lipids associated with type 2 diabetes and obesity. Regulation of lipid metabolism is crucial in the improvement of type 2 diabetes and obesity associated symptoms. The role of CaMKII in membrane associated lipid metabolism was the focus of this study. Five to six weeks old male Wistar rats were used in this study. GC×GC-TOFMS technique was used to determine the levels of polyunsaturated fatty acids (linoleic acid, arachidonic acid and 11,14-eicosadienoic acid)...
September 22, 2017: Physiological Research
https://www.readbyqxmd.com/read/28925692/occurrence-of-natural-mixed-halogenated-dibenzo-p-dioxins-specific-distribution-and-profiles-in-mussels-from-seto-inland-sea-japan
#12
Akitoshi Goto, Nguyen Minh Tue, Masayuki Someya, Tomohiko Isobe, Shin Takahashi, Shinsuke Tanabe, Tatsuya Kunisue
In addition to unintentional formation of polychlorinated (PCDD/Fs), polybrominated (PBDD/Fs), and mixed halogenated (PXDD/Fs) dibenzo-p-dioxins/dibenzofurans during industrial activities, recent studies have shown that several PBDD and PXDD congeners can be produced by marine algal species from the coastal environment. However, multiple exposure status of anthropogenic and naturally derived dioxins in marine organisms remains unclear. The present study examined the occurrence, geographical distribution, and potential sources of PCDD/Fs, PBDD/Fs, and PXDD/Fs using mussels and brown algae collected in 2012 from Seto Inland Sea, Japan...
October 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28917730/direct-and-comprehensive-analysis-of-dyes-based-on-integrated-molecular-and-structural-information-via-laser-desorption-laser-postionization-mass-spectrometry
#13
Rong Liu, Zhibin Yin, Yixin Leng, Wei Hang, Benli Huang
Laser desorption laser postionization time-of-flight mass spectrometry (LDPI-TOFMS) was employed for direct analysis and determination of typical basic dyes. It was also used for the analysis and comprehensive understanding of complex materials such as blue ballpoint pen inks. Simultaneous emergences of fragmental and molecular information largely simplify and facilitate unambiguous identification of dyes via variable energy of 266nm postionization laser. More specifically, by optimizing postionization laser energy with the same energy of desorption laser, the structurally significant results show definite differences in the fragmentation patterns, which offer opportunities for discrimination of isomeric species with identical molecular weight...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28911941/headspace-solid-phase-microextraction-coupled-to-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry-for-the-analysis-of-aerosol-from-tobacco-heating-product
#14
Benjamin Savareear, Radoslaw Lizak, Michał Brokl, Chris Wright, Chuan Liu, Jean-Francois Focant
A method involving headspace solid-phase microextraction (HS-SPME) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) was developed and optimised to elucidate the volatile composition of the particulate phase fraction of aerosol produced by tobacco heating products (THPs). Three SPME fiber types were studied in terms of extraction capacity and precision measurements. Divinylbenzene polydimethylsiloxane appeared as the most efficient coating for these measurements...
September 7, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28890492/a-quantitative-analysis-of-an-oil-component-in-an-emulsion-by-multiphoton-ionization-mass-spectrometry
#15
Hirofumi Fukaya, Tomohiro Uchimura
The first quantitative analysis of an oil component in an emulsion was achieved by multiphoton ionization time-of-flight mass spectrometry (MPI-TOFMS). An oil-in-water (O/W) emulsion was prepared. Styrene (0 - 5000 ng μL(-1)) and Triton X-100 were used as the oil phase and the disperser, respectively. Toluene was employed as an internal standard. We obtained a series of mass spectra, and then constructed the time profiles for styrene and toluene. As a result, we found several spikes from both time profiles when measuring emulsions with higher concentrations of styrene...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/28865386/response-of-rhizobium-to-cd-exposure-a-volatile-perspective
#16
Paulo Cardoso, Magda Santos, Rosa Freitas, Sílvia M Rocha, Etelvina Figueira
The volatile metabolome of Rhizobium sp. strain E20-8 exposed to three concentrations of cadmium (2.5, 5.0 and 7.5 μM) was screened using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GC × GC-ToFMS), combined with headspace solid phase microextraction (HS-SPME). Cd exposure induced a global increase in the concentration of volatile organic compounds (VOCs) both intra and extracellularly. Peak areas of several linear alkanes, ketones, aldehydes, alcohols, terpenic and volatile sulfur compounds, and one ester (ethyl acetate), were especially increased when compared with the control condition (no Cd)...
December 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28843553/comparison-of-a-disposable-sorptive-sampler-with-thermal-desorption-in-a-gas-chromatographic-inlet-or-in-a-dedicated-thermal-desorber-to-conventional-stir-bar-sorptive-extraction-thermal-desorption-for-the-determination-of-micropollutants-in-water
#17
Madelien Wooding, Egmont R Rohwer, Yvette Naudé
The presence of micropollutants in the aquatic environment is a worldwide environmental concern. The diversity of micropollutants and the low concentration levels at which they may occur in the aquatic environment have greatly complicated the analysis and detection of these chemicals. Two sorptive extraction samplers and two thermal desorption methods for the detection of micropollutants in water were compared. A low-cost, disposable, in-house made sorptive extraction sampler was compared to SBSE using a commercial Twister sorptive sampler...
September 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28830588/chemotyping-of-new-hop-humulus-lupulus-l-genotypes-using-comprehensive-two-dimensional-gas-chromatography-with-quadrupole-accurate-mass-time-of-flight-mass-spectrometry
#18
DanDan Yan, Yong Foo Wong, Laura Tedone, Robert A Shellie, Philip J Marriott, Simon P Whittock, Anthony Koutoulis
Comprehensive two-dimensional gas chromatography with quadrupole accurate mass time-of-flight mass spectrometry (GC×GC-Q-TOFMS) is employed to profile Humulus lupulus L. (hop) essential oils. Comparison of characterised essential oils allows discrimination among chemotypes. Experimental and commercial hop genotypes displayed distinguishable chemotypic patterns among the volatile secondary metabolites making up their essential oils. In total, 210-306 unique compounds were detected (depending on specific genotype), with 99 of these compounds either positively or tentatively identified...
August 9, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28830000/fate-and-abundance-of-classical-and-heteroatomic-naphthenic-acid-species-after-advanced-oxidation-processes-insights-and-indicators-of-transformation-and-degradation
#19
Mohamed N A Meshref, Pamela Chelme-Ayala, Mohamed Gamal El-Din
The toxicological effects from all components in oil sands process-affected water (OSPW) are not known. Alternatively, monitoring the variations and abundance of different classes and compounds after treatments might be a useful approach in OSPW remediation. In this study, the variations in the compositions of classical and heteroatomic naphthenic acids (NAs) after treatment using advanced oxidation processes (AOPs), mainly ozone and peroxone, and two different mass spectrometry methods; ultra-performance liquid chromatography time-of-flight (UPLC-TOFMS) and Fourier transform ion cyclotron resonance (FTICR-MS), were examined...
November 15, 2017: Water Research
https://www.readbyqxmd.com/read/28814125/recreational-drug-use-at-a-major-music-festival-trend-analysis-of-anonymised-pooled-urine
#20
Lotte Christine Groth Hoegberg, Cecilie Christiansen, Jesper Soe, Rasmus Telving, Mette Findal Andreasen, Dan Staerk, Lona Louring Christrup, Kenneth Thermann Kongstad
OBJECTIVE: The spread of new psychoactive substances (NPS) has expanded rapidly in the last decade. The complexity of the pharmacological effects of NPS challenges the traditional treatment guidelines, and information of the emergence of new arrivals is valuable. Our knowledge on the actual range of recreational drugs used and NPS available in Denmark is limited as identification is possible only when consumers become patients in the healthcare system or through drug seizures. We aimed to detect classical recreational drugs and NPS in the urine of music festival attendees and evaluate if the use of NPS could have been predicted by comparing study data with drug seizure data from the previous year published by European and Danish health authorities...
August 17, 2017: Clinical Toxicology
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