Search results for "Gas Chromatography"
showing 10 items of 750 documents
Volatile constituents of aerial parts of three endemic Centaurea species from Turkey: Centaurea amanicola Hub.-Mor., Centaurea consanguinea DC. and C…
2008
The volatile constituents of the aerial parts of Centaurea amanicola Hub.-Mor., Centaurea consanguinea DC. and Centaurea ptosimopappa Hayek were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 94 components were identified. Sesquiterpenoids, fatty acids and carbonylic compounds were the most abundant components in the oils. Hexadecanoic acid and (Z,Z )-9,12-octadecadienoic acid were the main fatty acids in all the examined samples, that showed different patterns of composition. The study on the biological activity of the oils showed an action mainly against the Gram-positive pathogens.
Essential oil of Citrus lumia Risso: Phytochemical profile, antioxidant properties and activity on the central nervous system
2018
Citrus lumia Risso Essential oil Antioxidant properties Anti-cholinesterase activity Cytotoxicity Neuroactive effects 1. Introduction Plants that produce essential oils (EOs) represent a large part of natural flora and an important resource in various fields such as pharmaceutical, food and cosmetic industries, due to their flavor, fra- grance and biological activity (Swamy et al., 2016). EOs play a pivotal role in the growth and colonization of plants, giving color and scent to reproductive organs, attracting pollinators, favoring seed dispersion (Sharifi-Rad et al., 2017), and defending the plant against abiotic (light, temperature, etc.) and biotics (herbivores, harmful insects and pa- t…
Neurosteroidogenesis in Rat Retinas
2002
Neurosteroids (steroids synthesized in the CNS) function by modulating neurotransmission. To establish an experimental model for investigation of neurosteroid synthesis and regulation, independent of blood-borne steroids, we examined the steroidogenic activity of isolated rat retinas. We identified progesterone, pregnenolone, dehydroepiandrosterone, desoxycorticosterone, 3 alpha,5 alpha-tetrahydrodesoxycorticosterone, 3 alpha-hydroxy-5 alpha-dihydroprogesterone, 17-hydroxyprogesterone, and 17-hydroxypregnenolone together with their esterified forms. As pregnenolone is the precursor of all steroids, its formation was studied in detail as an index of a steroid-synthesizing tissue. Pregnenolon…
HPLC: a tool for the analysis of T-2 toxin and HT-2 toxin in cereals.
1984
An analytical procedure for the determination of trichothecenes in various cereals is described. HPLC was performed with a reversed-phase (C18) column eluted with methanol:water (60:40, v/v). Compounds were detected with a refractive index detector. The elution patterns of free and contaminated samples were compared. The recovery of added T-2 toxin (2 and 5 micrograms/g) in rye and wheat was approximately 80%. The application of this method allows for combined use with other sensitive methods such as mass spectrometry and gas chromatography. The described method is operationally simple, relatively inexpensive, and requires no derivatization.
Understanding retention and metabolization of aroma compounds using an in vitro model of oral mucosa.
2020
International audience; The mechanism leading to aroma persistence during eating is not fully described. This study aims at better understanding the role of the oral mucosa in this phenomenon. Release of 14 volatile compounds from different chemical classes was studied after exposure to in vitro models of oral mucosa, at equilibrium by Gas-Chromatography-Flame Ionization Detection (GC-FID) and in dynamic conditions by Proton Transfer Reaction- Mass Spectrometry (PTR-MS). Measurements at equilibrium showed that mucosal hydration reduced the release of only two compounds, pentan-2-one and linalool (p < 0.05), and suggested that cells could metabolize aroma compounds from different chemical fa…
Analytical Study of a Resinous Material Used as Sealing in Ancient Pottery Found in an Archaeological Site by Thermally Assisted Hydrolysis Methylati…
2009
Abstract A resin sample was found in the archaeological site of Lixus (Morocco), belonging to the second century BC. The resinous material was found inside an amphora containing iron remains used in the plug as sealing material to hermetically close the pottery. The resinous sample was studied by several analytical techniques, as thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry (THM–GC–MS), Fourier transformed infrared spectroscopy (FTIR), and light microscopy. The material was identified as a Pinaceae resin. Therefore, a modern pine resin was also analyzed to consider the influence of aging in the archaeological sample. The ancient material was found not t…
Micro-analytical identification of the components of varnishes from South Italian historical musical instruments by PLM, ESEM-EDX, microFTIR, GC-MS, …
2014
Abstract A multi-analytical investigation was carried out to study varnish micro-samples from historical stringed musical instruments from the collection of the “Vincenzo Bellini” Conservatory in Palermo (Italy). This paper reports on the results of the application of five micro-destructive techniques: optical microscopy analysis of cross-sections, micro-Fourier transform infrared spectroscopy, gas chromatography coupled with mass spectrometry, pyrolysis gas chromatography coupled with mass spectrometry with thermochemolysis, and environmental scanning electron microscopy with X-ray microanalysis. The study provides microchemical information about the composition of the varnishes of the ins…
Application of TLC and GC-MS to the detection of capsaicin from hot peppers(Capsicum annuum)
2004
Capsaicin was extracted from red hot pepper (Capsicum annuum) fruits and from commercial red hot pepper powder and separated on silica gel 60 plates with concentration zone (Merck); toluene-acetone-chloroform, 45 + 30 + 25 ( v/v ), was used as mobile phase. Detection was performed by exposure to iodine vapor. The spots assumed to arise from capsaicin were removed from the plate and the components were extracted with chloroform. The extracts were analyzed by gas chromatography combined with mass spectrometry.
Gas chromatographic-mass spectrometric analysis of chlorinated phenoxyphenols in the technical chlorophenol formulation ky-5′
1984
Abstract The content of polychlorinated phenoxyphenol (PCPP) impurities in the technical chlorophenol formulation Ky-5 (wood preservative) was studied. The phenolic fraction was shown to contain predioxins and isopredioxins, the structures of the components being verified by gas chromatography mass spectrometry of non-derivatized, methylated and acetylated fractions. 2,6-Dichloro-4-(2,4,6-trichlorophenoxy)phenol and 2,6-dichloro-4-(2,3,4,6-tetrachlorophenoxy)phenol were identified by the comparison of their retention times and the mass spectra of their methyl and acetyl derivatives with those of authentic specimens. The amounts of the above components in Ky-5 were ca. 0.8 and 0.2%, respecti…
Polychlorinated phenols and their metabolites in soil and earthworms of sawmill environment
1990
Abstract Topsoil and earthworm samples collected from three Finnish sawmill environments were analysed for polychlorinated phenols, 2,3,4,6-tetrachloro- and pentachlorophenol, and their metabolites. Analyses were carried out by gas chromatography/mass spectrometry using a selected ion monitoring technique and by dual-channel gas chromatography using quartz capillary columns and two electron capture detectors. The total chlorophenol concentrations ranged from ca. 260 to 480 μg/g (dry weight) in soil and from ca. 140 to 3500 μg/g fat in earthworms. The most important metabolites in soil were chlorinated dihydroxy-benzenes (also at ppm level); only traces of chlorinated anisoles were detected …