104,924 research outputs found
Identifying metabolites by integrating metabolome databases with mass spectrometry cheminformatics.
Novel metabolites distinct from canonical pathways can be identified through the integration of three cheminformatics tools: BinVestigate, which queries the BinBase gas chromatography-mass spectrometry (GC-MS) metabolome database to match unknowns with biological metadata across over 110,000 samples; MS-DIAL 2.0, a software tool for chromatographic deconvolution of high-resolution GC-MS or liquid chromatography-mass spectrometry (LC-MS); and MS-FINDER 2.0, a structure-elucidation program that uses a combination of 14 metabolome databases in addition to an enzyme promiscuity library. We showcase our workflow by annotating N-methyl-uridine monophosphate (UMP), lysomonogalactosyl-monopalmitin, N-methylalanine, and two propofol derivatives
An integrated approach to the study of Ri de pomme, a painting by Julian Schnabel
The painting Ri de Pomme (1988) by American artist Julian Schnabel was recently subjected to an extensive and disputed restoration with polyvinyl acetate (PVAc) paints. To characterize and locate on the painting the materials used in the original and in the repainted areas, we employed several spectroscopic and chromatographic techniques. Fibre Optics Reflectance Spectroscopy (FORS), Micro-Raman, Pyrolysis-Gas Chromatography/Mass Spectrometry (Py- GC/MS) and Gas Chromatography/Mass Spectrometry (GC/MS) were used. The original and restoration paint layers were differentiated by a preliminary FORS survey. The pigments were studied with Micro-Raman and the oil binder was characterized by GC/MS. Moreover, the support of the painting, a weathered tarpaulin, was characterized by Py-GC/MS
Chemical analysis of racing fuels using total vaporization and gas chromatography mass spectrometry (GC/MS)
The National Hot Rod Association (NHRA) is the governing body of North American drag racing. As a supervisory agency, NHRA monitors racing fuels for regulatory purposes and quality control. In this paper, total vaporization and mass spectrometry based methods were developed to analyze nitromethane-based and racing gasoline fuels. Total Vaporization Headspace gas chromatography mass spectrometry (TV-HS-GC/MS) was used to quatitate the amount of methanol in nitromethane fuels to verify that the methanol content was at least 10% (v/v). Total vaporization solid phase microextraction gas chromatography mass spectrometry (TV-SPME-GC/MS) was used to qualitatively identify racing gasoline components, which included isopentane, isooctane, toluene, and tetraethyllead
Spectroscopic Techniques and Their Application in Metabolic Profiling of Wood: A Minireview
GC/LC-MS and NMR spectroscopy have increasingly occupied a central position in the methodologies developed for metabolic analysis. This brief review deals with introduction of terminology used in metabolic analysis. Gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR) commonly used in metabolic analysis and metabolic profiling of wood and wood based material by spectroscopic techniques. Apart from the description of the different methods, this review will try to direct the reader to the main approaches for analysis of metabolites in wood science. Keywords: Metabolic profiling, Wood, GC/LC-MS, NMR Spectroscopy
Introductory Chapter: Analytical Pyrolysis-Gas Chromatography/ Mass Spectrometry of Polymeric Materials
According to the International Union of Pure and Applied Chemistry (IUPAC) recommendation, analytical pyrolysis (Py) is defined as the characterization in an inert atmosphere of a material or a chemical process by a chemical degradation reaction(s) induced by thermal energy [1]. Thermal degradation under controlled conditions is often used as a part of an analytical procedure, either to render a sample into a suitable form for subsequent analysis by gas chromatography (GC), mass spectrometry (MS), gas chromatography coupled with the mass spectrometry (GC/MS), with the Fourier-transform infrared spectroscopy (GC/FTIR), or by direct monitoring as an analytical technique in its own right [2]
Utility of comprehensive GCĂ—GC Gas Chromatography in finding varietal markers among volatile compounds in non-aromatic red wines
To investigate the utility of comprehensive GC×GC gas chromatography metabolomics in finding varietal markers among volatile compounds in non-aromatic red wines, representative samples of the two most important Croatian monovarietal red wines, Plavac mali and Teran, were subjected to analysis by both conventional gas chromatography–mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOF-MS) after headspace solid-phase microextraction (HS-SPME). GC-MS was useful for the determination of the basic volatile profile composed mainly of major esters and acids, followed by terpenes and C13-norisoprenoids. GC×GC-TOF-MS allowed the identification of 209 volatiles, among which 49 were significantly different across monovarietal wines. The compounds most characteristic for Teran were two theaspirane isomers, ethyl 3-(methylsulfanyl)propanoate, ethyl methyhexanoate, and ho-trienol, whereas Plavac mali stood out with higher concentrations of tridecane and a 2,3-butanediol isomer. The two monovarietal wines were successfully differentiated between each other by multivariate statistical methods mostly based on GC×GC-TOF-MS data. The presented approach that combines conventional GC-MS and advanced GC×GC-TOF-MS showed a great potential for tracking chemical markers of varietal origin and could be practically applied in managing wine production, quality and typicity, marketing, and protection from forger
Determination of acrylamide in food by gas and liquid chromatography-mass spectrometry
Acrylamide in food was determined by gas chromatography - mass spectrometry (GC-MS) after bromination of acrylamide and underivatized acrylamide was quantified by ultra performance liquid chromatography -mass spectrometry (UPLC-MS). Two different sample preparation methods were used and optimised. The GC-MS method was used for various food matrices like breads, potato crisps, potato crackers, french fries. The UPLC-MS method was used for analysis of coffee. The limit of detection and limit of quantification for acrylamide were 7 µg.kg-1 and 20 µg.kg-1 by GC-MS, 9 µg.kg-1  and 30 µg.kg-1 by UPLC-MS. For both methods the reproducibility, given as relative standard deviation was < 5% , and the recovery was close to 100 %
Determination of sorbitol in the presence of high amount of mannitol from biological samples
Preparation of intact mitochondria requires the use of an osmoticum in high concentration that preserves the mitochondrial structure and prevents physical swelling and rupture of membranes. For this purpose mannitol is widely accepted as a component of the homogenization medium. The formation of sorbitol in plant mitochondria can be an important element of plant response to salinity and drought. The large difference in the concentration of possibly formed sorbitol and mannitol of the homogenisation medium makes the determination of sorbitol difficult. Gas-chromatography with flame ionization detection (GC-FID), gas-chromatography coupled to quadrupole mass spectrometry (GC-QPMS) and liquid chromatography/tandem mass spectrometry (LC/MS-MS) using hydrophilic interaction chromatography (HILIC) were tested to quantify this highly polar sugar alcohol: Although all three methods offered satisfactory results, the HPLC/MS-MS technique proved to be the best
A Novel Approach by SPME-GC/MS for the Determination of gammahydroxybutyric acid (GHB) in Urine Samples after Conversion into gamma-butyrolactone (GBL)
The quantitative determination of gamma-hydroxybutyric acid (GHB) in urine samples is very important to assess illicit intake or administration. To this end we evaluated several analytical methods: headspace gas-chromatography coupled to flame ionization detection (HS-GC/FID), headspace gas-chromatography coupled to mass spectrometry (HS-GC/MS), headspace gas-chromatography coupled to solid phase microextraction and mass spectrometry (HS-SPME-GC/MS). All these methods were endowed with a not sufficient sensitivity, and then we moved to solid phase microextraction coupled to gas-chromatography with mass spectrometry detection (SPME-GC/MS). At first, GHB was extracted from urine with an organic solvent and analyzed after derivatization. Under these conditions, however, there was a partial overlapping between the chromatographic peak of GHB and that of urea, also extracted by the organic solvent. Then we decided to change analytical approach and to convert GHB to gamma-butyrolactone (GBL), which is not an endogenous compound. A SPME method was optimized and validated for the determination of GBL. The limit of detection (LOD) of the method resulted to be 0.25 \u3bcg/mL for GBL, corresponding to 0.5 \u3bcg/mL for GHB. The lower limit of quantification (LLOQ) was 0.4 \u3bcg/mL for GBL and 0.8 \u3bcg/mL for GHB. The LLOQ of the method resulted 10 times lower than the endogenous level, thus allowing to distinguish between physiological conditions and exogenous assumption
IDENTIFICATION OF BIOACTIVE COMPOUNDS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY ANALYSIS OF SYZYGIUM JAMBOS (L.) COLLECTED FROM WESTERN GHATS REGION COIMBATORE, TAMIL NADU
Objective: The aim of this study was to investigate the presence of bioactive compounds in the methanolic leaf extract of Syzygium jambos.Methods: Collected leaves were shade dried and made into fine powder, extracted with methanol, and the methanolic extract was prepared and analyzed for the presence of bioactive compounds by gas chromatography-mass spectrometry (GC-MS). The mass spectrum of the chromatography was matched with NIST and WILEY Libraries.Results: The GC-MS analysis revealed the presence of 45 active compounds in the extract. From the GC-MS investigation, 1-Deoxy-d-mannitol3-methyl-2-methylsulfanyl-5-nitro-6-pyridin-4-ylpyrimidin-4-one, 3-Pentadecylphenol, 2-biphenylene carboxylic acid, Quinoline-3-carboxylic acid, and Stigmast-5-en-3-ol are important phytoconstituents which have antipyretic and antiparasitic activities.Conclusion: The present investigation revealed preliminary information on phytocompounds presented in S. jambos leaf extract which is very useful for the human community.Keywords: Syzygium jambos, Gas chromatography-mass spectrometry analysis, 1-Deoxy-d-mannitol, Phytoconstituents, Methanolic leaf extrac
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