Search results for "Gas Chromatography"

showing 10 items of 750 documents

The influence of storage conditions on flavour changes in human milk

2009

http://www.sciencedirect.com/ ; http://www.elsevier.com/; International audience; The effects of freeze-storage on human milk have been investigated with regard to sensory changes and modifications in the molecular composition of constituent odour-active volatiles. Sensory evaluation showed that fishy-metallic odour attributes are generated during storage, as are rancid-sweaty odour notes, which were described by panellists to be highly unpleasant. To monitor the dynamics of off-odour development in human milk, sensory evaluation in both orthonasal and retronasal mode was performed at defined time intervals of storage, with parallel evaluation of human milk samples that had been heated prio…

030309 nutrition & dietetics[ SDV.AEN ] Life Sciences [q-bio]/Food and NutritionFlavourFood storageBreastfeeding03 medical and health sciences0404 agricultural biotechnology[SDV.IDA]Life Sciences [q-bio]/Food engineeringparasitic diseasesAcidGas chromatography olfactometryFood science(Z)-Octa-15-dien-3-oneGeneralLiterature_REFERENCE(e.g.dictionariesencyclopediasglossaries)FlavorComputingMilieux_MISCELLANEOUS2. Zero hungerchemistry.chemical_classification0303 health sciencesNutrition and DieteticsFishyOff-flavourFood preservationfood and beveragesFood composition data04 agricultural and veterinary sciences[SDV.IDA] Life Sciences [q-bio]/Food engineering040401 food scienceOff-flavourchemistryBiochemistryMetallicFood quality[SDV.AEN]Life Sciences [q-bio]/Food and NutritionFood SciencePolyunsaturated fatty acid
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Substituted Dibenzothiophenes I: Synthesis, Chromatography, Mass Spectrometry and Structure Elucidation by1H NMR Spectroscopy

1992

Abstract Some polychlorinated and polymethylated dibenzothiophenes have been synthesized to serve as model compounds in environmental analysis. In order to obtain pure isomers, the synthesis mixtures have been fractionated with reversed-phase high performance liquid chromatography. In spite of a high sensitivity, mass spectrometry does not provide any reliable way to determine the precise structures of different isomers. Therefore, 1H NMR spectroscopy has been utilized as an aid in their analysis. The structures for two isomeric tetramethyldibenzothiophenes could be suggested on the basis of their 1H NMR spectra. Also some proposals for possible structures of two isomeric trimethyldibenzoth…

1h nmr spectroscopyChromatographyChemistryHealth Toxicology and MutagenesisPublic Health Environmental and Occupational HealthSoil ScienceReversed-phase chromatographyMass spectrometryPollutionHigh-performance liquid chromatographyAnalytical ChemistryProton NMRStructural isomerEnvironmental ChemistryOrganic chemistryGas chromatographyWaste Management and DisposalWater Science and TechnologyInternational Journal of Environmental Analytical Chemistry
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Formation of 2,4,6-trichlorophenol and 2,4,6-trichloroanisole during treatment and distribution of drinking water

1995

Biomethylation of 2,4,6-trichlorophenol to the potent off-flavour compound 2,4,6-trichloroanisole has previously been found to cause taste and odour problems in drinking water. In the present study, both compounds were detected in seemingly unpolluted surface waters. However, the highest concentrations of 2,4,6-trichloroanisole in tap water were caused by the formation of 2,4,6-trichlorophenol during chlorine disinfection of drinking water and subsequent methylation of this compound in the distribution system. Analysis of samples from several sites in the investigated distribution systems showed that there was a substantial spatial and temporal variation of the concentration of both 2,4,6-t…

246-TrichloroanisoleEnvironmental EngineeringOff-flavourchemistry.chemical_elementchemistry.chemical_compoundchemistryTap waterEnvironmental chemistry246-TrichlorophenolChlorineWater treatmentGas chromatographyPhenolsWater Science and TechnologyWater Science and Technology
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Volatile components of dry-cured ham

1991

The volatile components of dry-cured ham were isolated by vacuum distillation and analyzed by gas chromatography-mass spectrometry. The structures of 76 molecules were identified by mass spectrometry, cochromatography, or measured Kovats indices. The compounds identified may come from the catabolism of the main constituent parts of the meat (glucids, lipids and protids) during the curing of the hams, from the pig feed, or from technological processes. The volatile compounds extracted from 50 g of ham according to the technique described correspond to a chromatographical surface equivalent to 0.12 mg of the dodecane internal standard, or approximately 2.4 ppm of the weight of the sample. Fla…

2. Zero hungerCuring (food preservation)ChromatographyDodecaneVacuum distillation0402 animal and dairy science04 agricultural and veterinary sciencesGeneral Chemistry[SDV.IDA] Life Sciences [q-bio]/Food engineeringMass spectrometry040401 food science040201 dairy & animal sciencechemistry.chemical_compound0404 agricultural biotechnologychemistryOdor[SDV.IDA]Life Sciences [q-bio]/Food engineeringGas chromatographyGeneral Agricultural and Biological SciencesDry curedFlavorComputingMilieux_MISCELLANEOUS
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Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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Metabolic signatures across the full spectrum of non-alcoholic fatty liver disease.

2022

Funder: European Commission

ALTtype 2 diabetes mellitusROC receiving operator characteristicaspartate aminotransferaseHSDLDL low-density lipoproteinUHPLC ultrahigh-performance liquid chromatographyROCHCCNon-alcoholic steatohepatitisGCPCANASHGastroenterology2-HB 2-hydroxybutanoic acid; 3-HB 3-hydroxybutanoic acid; ALT alanine aminotransferase; AST aspartate aminotransferase; CE cholesterol ester; Cer ceramide; FFA free fatty acid; FLIP Fatty Liver Inhibition of Progression; Fibrosis; GC gas chromatography; HCC hepatocellular carcinoma; HSD honest significant difference; LC lipid cluster; LDL low-density lipoprotein; LM lipid and metabolite; LMC lipid metabolite and clinical variable; LPC lysophosphatidylcholine; Lipidomics; Mass spectrometry; Metabolomics; NAFL non-alcoholic fatty liver; NAFLD non-alcoholic fatty liver disease; NAS NASH activity score; NASH non-alcoholic steatohepatitis; NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network; NRR non-rejection rate; Non-alcoholic steatohepatitis; PC(O) ether PC; PC phosphatidylcholine; PCA principal component analysis; PE phosphatidylethanolamine; QTOFMS quadrupole-time-of-flight mass spectrometry; ROC receiving operator characteristic; SAF steatosis activity and fibrosis; SM sphingomyelin; T2DM type 2 diabetes mellitus; TG triacylglycerol; UHPLC ultrahigh-performance liquid chromatographySAFSAF steatosis activity and fibrosisLM lipid and metabolitehonest significant differenceHSD honest significant differenceTG triacylglycerolnon-rejection ratecholesterol esterPCPEGC gas chromatographyfree fatty acidFLIPNASH non-alcoholic steatohepatitisNIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkBIOMARKERST2DMPE phosphatidylethanolamineLDLlipidNAFLDFFA free fatty acid2-HBMetabolomicsNAFL non-alcoholic fatty liverLMCphosphatidylcholineScience & TechnologySM sphingomyelinGastroenterology & HepatologyMass spectrometryactivitynutritional and metabolic diseasesT2DM type 2 diabetes mellitusACIDSreceiving operator characteristicdigestive system diseasesquadrupole-time-of-flight mass spectrometryLC lipid clusterlow-density lipoproteinNAS2-HB 2-hydroxybutanoic acidNAS NASH activity scoreQTOFMSether PCNRRSCORING SYSTEMprincipal component analysisgas chromatographyLC2-hydroxybutanoic acidPROGRESSIONAST aspartate aminotransferaseLMPC phosphatidylcholinePC(O)MARKERSUHPLCsteatosisTOOLImmunology and AllergyINSULIN-RESISTANCECerSMFatty Liver Inhibition of Progressionhepatocellular carcinoma2-HB 2-hydroxybutanoic acid NIDDK NASH-CRN National Institute of Digestive Diseases and Kidney NASH Clinical Research Network NRR non-rejection rate Non-alcoholic steatohepatitis PC(O) ether PC PC phosphatidylcholine PCA principal component analysis PE phosphatidylethanolamine QTOFMS quadrupole-time-of-flight mass spectrometry ROC receiving operator characteristic SAF steatosis activity and fibrosis SM T2DM type 2 diabetes mellitus TG triacylglycerol UHPLC ultrahigh-performance liquid chromatographyultrahigh-performance liquid chromatographyCELPC3-HBNAFLnon-alcoholic fatty liverTGtriacylglycerolNRR non-rejection rateLife Sciences & BiomedicineNAFLD non-alcoholic fatty liver diseaseFLIP Fatty Liver Inhibition of Progressionalanine aminotransferasemetaboliteCer ceramideCE cholesterol estersphingomyelinlysophosphatidylcholineand fibrosisALT alanine aminotransferaseInternal MedicineceramideNational Institute of Digestive Diseases and Kidney NASH Clinical Research NetworkAST3-HB 3-hydroxybutanoic acidQTOFMS quadrupole-time-of-flight mass spectrometryPCA principal component analysisLPC lysophosphatidylcholineHepatologynon-alcoholic fatty liver diseaseand clinical variablePC(O) ether PC3-hydroxybutanoic acidFibrosisNASH activity scoreNIDDK NASH-CRNlipid clusterlipid and metabolitephosphatidylethanolamineLipidomicsLMC lipid metabolite and clinical variableFFAHCC hepatocellular carcinomaJHEP reports : innovation in hepatology
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Analysis of emerging and related pollutants in aquatic biota

2020

Water bodies cover approximately 70 % of the earth s surface, making them ecosystems with a high environmental value and the habitat for numerous species of flora and fauna. Emerging pollutants (EPs) are ubiquitous anthropogenic compounds of environmental concern that can be found at different concentration levels in matrices such as sediment, water and aquatic biota. In addition, EPs can be bioaccumulated and biomagnified, inducing adverse effects on biota, and posing a risk to humans when contaminated biota is consumed. Unlike abiotic matrices, the occurrence of EPs in aquatic biota has not been widely studied. This is probably because their complexity, due to the presence of lipids, prot…

Abiotic componentPollutantAquatic biotaGas chromatographySpectrometryFauna010401 analytical chemistryLiquid chromatographyMethodologySedimentBiotaExtraction010501 environmental sciencesAquatic biota01 natural sciences0104 chemical sciencesAnalytical ChemistryLipids removalHabitatEnvironmental chemistryEnvironmental ChemistryEnvironmental scienceEcosystem0105 earth and related environmental sciences
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Effect of simulated gastrointestinal digestion on plant sterols and their oxides in enriched beverages

2013

Abstract This study evaluates the bioaccessibility (percentage of soluble compound available for absorption) of plant sterols (PS) and their oxides (phytosterol oxidation products, POPs) after simulated gastrointestinal digestion in fruit (Fb), milk (M) and fruit-based milk beverages with (FbM a ) or without (FbM b ) tangerine juice. In beverages and their bioaccessible fraction (BF), campesterol, campestanol, stigmasterol, β-sitosterol and sitostanol were detected. Bioaccessibility of total PS ranged between 2.62 and 6.48%, FbM b yielding the highest value, followed by FbM a  > Fb > M. Campesterol/campestanol were the most bioaccessible PS. Only oxides of β-sitosterol were detected in beve…

Absorption (pharmacology)StigmasterolChromatographyCampesterolPhytosterolBEVERAGESCampestanolPLANT STEROLchemistry.chemical_compoundchemistryPLANT STEROL; SIMULATED GASTROINTESTINAL DIGESTION; STEROL OXIDATION PRODUCTS; BEVERAGESFood scienceGas chromatography–mass spectrometrySolubilitySIMULATED GASTROINTESTINAL DIGESTIONPlant sterolsSTEROL OXIDATION PRODUCTSFood Science
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Development of microextraction techniques in combination with GC-MS/MS for the determination of mycotoxins and metabolites in human urine.

2017

Simple and highly efficient sample preparation procedures, namely, dispersive liquid–liquid microextraction and salting-out liquid–liquid extraction for the analysis of ten Fusarium mycotoxins and metabolites in human urine were compared. Various parameters affecting extraction efficiency were carefully evaluated. Under optimal extraction conditions, salting-out liquid–liquid extraction showed a better accuracy (84–96%) and precision (<14%) than dispersive liquid–liquid microextraction. Hence, a multibiomarker method based on salting-out liquid–liquid extraction followed by gas chromatography with tandem mass spectrometry was proposed. Satisfactory results in terms of validation were achiev…

Accuracy and precisionLiquid Phase MicroextractionFiltration and SeparationPilot ProjectsUrineUrinalysisTandem mass spectrometry01 natural sciencesGas Chromatography-Mass SpectrometryAnalytical Chemistry0404 agricultural biotechnologyLimit of DetectionTandem Mass SpectrometryHumansSample preparationDetection limitChromatographyChemistry010401 analytical chemistryExtraction (chemistry)04 agricultural and veterinary sciencesMycotoxins040401 food science0104 chemical sciencesGas chromatographyGas chromatography–mass spectrometryJournal of separation science
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Development of a GC–MS/MS strategy to determine 15 mycotoxins and metabolites in human urine

2014

The widespread mycotoxins contamination of food commodities has made the monitoring of their levels essential. To overcome the disadvantages of the indirect approach by food analysis, detection of mycotoxin as biomarkers in urine provides a useful and specific data for exposure assessment to these food contaminants. In this work, a sensitive, rapid and accurate method based on gas chromatography-tandem mass spectrometry procedure to determine 15 mycotoxins and metabolites in human urine was optimized and validated taking into consideration the guidelines specified in Commission Decision 2002/657/EC and 401/2006/EC. A salting-out assisted acetonitrile-based extraction was used for sample pre…

AcetonitrilesChromatographyChemistryExtraction (chemistry)Reproducibility of ResultsFood ContaminationGuidelines as TopicUrineMycotoxinsContaminationGas Chromatography-Mass SpectrometryFood AnalysisAnalytical Chemistrychemistry.chemical_compoundReference ValuesTandem Mass SpectrometryCalibrationHumansSample preparationGas chromatography–mass spectrometryChildMycotoxinBiomarkersFood contaminantTalanta
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