Search results for "Gas Chromatography"
showing 10 items of 750 documents
Volatile components from flower-heads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostál growing wi…
2008
The volatile constituents of the flowerheads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostal were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 113 components were identified. Fatty acids and hydrocarbons were the most abundant components in the oils. Caryophyllene and caryophyllene oxide were the main compounds of the sesquiterpene fraction. The study on the biological activity of the oils shows no significant activity.
Volatile compounds of flowers and leaves of Sideritis italica (Miller)Greuter et Burdet (Lamiaceae), a plant used as mountain tea
2010
Sideritis italica (Miller) Greuter et Burdet (Lamiaceae), widely used in ethnopharmacological medicine, occurs in Southern Italy and Sicily. The phytochemical composition of the essential oils of S. italica flowers and leaves, harvested in Piano Battaglia (Sicily), was analysed by GC and GC-MS. Of the 51 compounds, 43 in the oil from flowers and 29 in the oil from leaves were identified. Kaur-15-ene (20.0%) was recognised as the main constituent of the oil from flowers, together with beta-cubebene (12.1%), beta-pinene (8.5%), (Z)-nuciferol (6.5%), tricyclene (4.5%) and alpha-bisabolol (4.0%). In the oil from leaves, p-methoxyacetophenone (26.0%) prevailed, as did hexadecanoic acid (21.3%), …
Solid Phase Microextraction (SPME) of Orange Juice Flavor: Odor Representativeness by Direct Gas Chromatography Olfactometry (D-GC-O)
2003
The sensorial quality of solid phase microextraction (SPME) flavor extracts from orange juice was measured by direct gas chromatogrphy-olfactometry (D-GC-O), a novel instrumental tool for evaluating odors from headspace extracts. In general, odor impressions emerging from SPME extracts poorly resembled that of the original orange juice. In an attempt to improve the sensorial quality of extracts, sample equilibration and exposure times were varied on Carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibers. Best sensorial results were obtained with the DVB/CAR/PDMS fiber exposed for the shortest time; a trained panel of eight assess…
Volatile constituents of the aerial parts of white salsify (Tragopogon porrifolius L., Asteraceae).
2010
Tragopogon porrifolius L. grows as a vegetable in southern Italy and all parts of it are edible. In the present study the volatile components of the aerial part are described. Gas chromatography and gas chromatography-mass spectrometry analysis showed the presence of 38 components in all. On the whole, the volatile fraction was constituted mainly by carbonylic compounds (24.6%), phenols (21.5%) and fatty acids and esters (19.7%). The most abundant compounds were 4-vinyl guaiacol (19.0%), hexadecanoic acid (17.9%), hexahydrofarnesylacetone (15.8%) and hentriacontane (10.7%).
Chemical composition and phytotoxic effects of essential oils of Salvia hierosolymitana Boiss. and Salvia multicaulis Vahl. var. simplicifolia Boiss.…
2009
The chemical composition of the essential oils of S. hierosolymitana Boiss. and S. multicaulis Vahl. var. simplicifolia Boiss. collected in Lebanon was studied by means of GC and GC-MS analysis. In all 115 compounds were identified: 82 for S hierosolymitana and 72 for S. multicaulis var. simplicifolia. The presence of carbonylic compounds (17%) characterizes the oil from S. hierosolymitana, while S. multicaulis var. simplicifolia oil is rich of monoterpenes (34.5%) and sesquiterpenes (46.9%). The effects of the essential oils on germination and initial radical elongation of Raphanus sativus L. (radish) and Lepidium sativum L. (garden cress) were studied, indicating in a different activity a…
Determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin in goat milk and tissues by glass capillary gas chromatography and medium resolution mass fragme…
1981
Abstract An analytical method has been developed for the study of the elimination of 2,3,7,8-tetrachlodoribenzo-p-dioxin (TCDD) by lactation and its determination in various tissues of goat. The method is based on the alkaline hydrolysis of milk, liver, fat, muscle, blood, faeces and urine samples, extraction with n-hexane, treatment with sulphuric acid-saturated silica gel, chromatographic clean-up on silica gel and alumina micro-columns, and glass capillary gas chromatography—medium resolution mass fragmenography (resolution 2000). 1,2,3,4-Tetrachlorodibenzo-p-dioxin is used as the internal standard, the concentration of TCDD being determined from the calibration curve calculated from the…
Chemical composition of the essential oil of Salvia microstegia Boiss. et Balansa growing wild in Lebanon.
2005
The essential oil of aerial parts of Salvia microstegia Boiss. et Balansa (Lamiaceae) growing wild in Lebanon was obtained by hydrodistillation and was analysed by GC and GC–MS. 70 compounds, representing 94.0% of the oil, were identified. The major components were caryophyllene oxide (6.2%), pulegone (5.7%), 4-vinylguaiacole (5.3%), hexadecanoic acid (5.1%) and menthone (4.9%). © 2006 Elsevier B.V. All rights reserved.
Evidence in the formation of conjugated linoleic acids from thermally induced 9t12t linoleic acid: a study by gas chromatography and infrared spectro…
2009
Accepted version of article published in the journal: Chemistry and Physics of Lipids. Published version available on Science Direct: http://dx.doi.org/10.1016/j.chemphyslip.2009.07.002 Thermally induced isomerisation leading to the formation of conjugated linoleic acids (CLAs) has been observed for the first time during the thermal treatment of 9t12t fatty acid triacylglycerol, and methyl ester. Fifteen microlitre portions of the triacylglycerol sample containing 9t12t fatty acid (trilinoelaidin) were placed in micro glass ampoules and sealed under nitrogen, then subjected to thermal treatment at 250 degrees C. The glass ampoules were removed at regular time intervals, cut open, and the co…
GC and GC–MS analysis of the essential oil of Nepeta cilicica Boiss. ex Benth. from Lebanon
2013
The hydrodistillation of the aerial parts of Nepeta cilicica Boiss. ex Benth., collected in Lebanon in the Horsh Ehden reserve, yielded 0.13% (w/w) of essential oil. Gas chromatography (GC) and GC-mass spectroscopy analysis enabled the identification of 75 compounds representing 96.8% of the total oil. The most abundant compounds were spathulenol (15.1%), hexadecanoic acid (14%), δ-cadinene (5.5%) and α-copaene (4.5%). On the whole, the oil was constituted mainly by sesquiterpenes (45.9%), among which sesquiterpene hydrocarbons (27.6%) slightly prevailed over oxygenated sesquiterpenes (18.3%).
Volatile components of Centaurea eryngiodes Lam. and Centaurea iberica Trev.var. hermonis Bois. Lam.,two Asteraceae growing wild in Lebanon.
2005
The volatile components of the flowerheads of Centaurea eryngioides Lam. and Centaurea iberica Trev. var. hermonis Boiss. Lam. were obtained by hydrodistillation and identified by GC and GC–MS. Altogether 91 components, mostly fatty acids and hydrocarbons, were identified.