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Capillary GC (capillary + gc)
Selected AbstractsThermal Behaviour of Selected C10H16 MonoterpenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2006Achim Stolle Abstract The presented work investigates the thermal behaviour of selected monoterpenes under various reactor temperatures and residence times (carrier gas, reactor inserts). In addition to the analysis of the liquid products by capillary GC and GC-MS, chemical derivatisation techniques (Diels,Alder reaction, hydrogenation) were used to identify the liquid-phase products. A thermal conversion of ,-pinene (1), myrcene (2) and limonene (4) in a reaction network is presented and the experimental evidence for the formation of pyrolysis products by a biradical pathway is discussed. The reaction network was modified based on the identification of additional C10H16 terpene isomers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Character impact odorants from wild mushroom (Lactarius hatsudake) used in Japanese traditional foodFLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2010Mitsuo Miyazawa Abstract The components of the volatile oil from wild mushroom (Lactarius hatsudake), used in Japanese traditional food, were analysed and quantified for the first time by capillary GC and GC,MS. Seventy-six components were separated from the oil and of these 71 components were identified. The main components of the oil were oxidized sesquiterpenes [cis -isolongifolanone (624.9,,g/100,g), , -cedrene epoxide (578.7,,g/100,g), humulene epoxide III (453.9,,g/100,g), clovane (425.4,,g/100,g)], aliphatic acids [linoleic acid (585.9,,g/100,g) and palmitoleic acid (333.3,,g/100,g)]. Odour evaluation of the volatile oil from L. hatsudake was also carried out using GC,MS/olfactometry (GC,MS/O) and aroma extract dilution analysis (AEDA), from which it was found that hexanal, 4-dehydroviridiflorol, myliol and phenylacetaldehyde seem to contribute to the green, spicy and sweet odour of L. hatsudake. Copyright © 2010 John Wiley & Sons, Ltd. [source] Chemical variability of the leaf oil of 113 hybrids from Citrus clementina (Commun) × Citrus deliciosa (Willow Leaf)FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2008Félix Tomi Abstract Essential oils of 113 Citrus clementina (Commun) × Citrus deliciosa (Willow Leaf) hybrids were obtained from leaves collected on trees located in the same orchard. Their chemical composition was investigated by capillary GC, GC,MS and 13C-NMR and the results were submitted to statistical analysis. Three chemical compositions were characterized. The crossing between clementine and mandarin produces mainly leaf oils characterized by a composition similar to those of the parents (sabinene/linalool or methyl N-methylanthranylate). However, several samples exhibited an original composition (,- terpinene/linalool). Copyright © 2008 John Wiley & Sons, Ltd. [source] Chemical variability of peel and leaf oils of mandarinsFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2006Anne-Laure Fanciullino Abstract Peel and leaf oils of 35 mandarin cultivars, belonging to five different species, were obtained from fruits and leaves collected on mandarin-trees kept at the same pedoclimatic and cultural conditions. Their chemical composition was investigated by capillary GC, GC,MS and 13C-NMR and the results were submitted to a statistical analysis. Two major chemotypes, limonene and limonene/, -terpinene, were distinguished for peel oils, while five chemotypes, linalool, sabinene/linalool, , -pinene/linalool, , -terpinene and methyl N-methylanthranilate, were observed for leaf oils. The results were compared with those already reported by our groups. Copyright © 2005 John Wiley & Sons, Ltd. [source] Volatile constituents of the flowers of Clerodendron fragrans (Vent.) R. Br.FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2005K. C. Wong Abstract The volatile constituents of Clerodendron fragrans (Vent.) R. Br. flowers were analysed by capillary GC and GC,MS following isolation by hydrodistillation,extraction; 41 compounds were identified. Oxygenated monoterpenes and aromatic compounds originating from phenylpropanoid metabolism predominated, accounting for 41.2% and 36.0% respectively, of the total volatiles. The major components were linalol, benzyl acetate and benzyl benzoate. Copyright © 2005 John Wiley & Sons, Ltd. [source] Chemical constituents of the essential oils of Goniothalamus malayanus Hook. f. and Thoms.FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2002Ibrahim bin Jantan Abstract The chemical composition of the leaf, bark and root oils of Goniothalamus malayanus Hook. f. and Thoms. was examined by capillary GC and GC,MS. The leaf oil was made up mainly of sesquiterpenoids, of which ,-selinene (33.6%) was the dominant component. The other major compounds present were viridiflorol (13.1%), epi -globulol (7.7%), (E)-nerolidol (4.4%) and globulol (3.8%). The bark and root oils, which were qualitatively similar but with some variation in levels of the individual constituents, were also rich in sesquiterpenoids (97% and 95%, respectively), with eudesmols as the most abundant compounds. The bark oil contained a higher amount of ,-eudesmol (32.2%), ,-eudesmol (21.8%) and ,-eudesmol (6.6%) than the root oil. Copyright © 2002 John Wiley & Sons, Ltd. [source] Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 20013-nortricyclanols, Kinetics, XXXVIII, mechanisms of 1- Abstract The disappearance of 1- and 3-nortricyclanols (1-OH and 2-OH) in aqueous perchloric acid was followed by capillary GC at different temperatures and acid concentrations. 1-OH is ca 1000 times more reactive than 2-OH. The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products were studied. Both isomeric nortricyclanols react according to the AdE2 mechanism, i.e. the cyclopropane ring is protonated at the rate-determining stage of the reaction. The protonation causes, in the case of 1-OH, an isomerization called homoketonization with 2-norbornanone as the only product and, in the case of 2-OH, hydration, i.e. the formation of hydroxyl-substituted norbornyl cations, the fast attack of which by water produces several norbornanediols. Copyright © 2001 John Wiley & Sons, Ltd. [source] Gas chromatographic retention in uncoated fused silica capillariesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2009Matthew S. Klee Abstract Understanding of retention in uncoated fused-silica capillaries is of interest due to increased attention on precolumn backflushing in capillary GC. Uncoated capillaries offer several advantages as precolumns compared to coated precolumns. In order to examine the possibility of predicting elution temperatures of alkanes from uncoated capillaries a priori, several sizes of deactivated but uncoated fused-silica capillaries were evaluated under various operating conditions. Retention was found to depend on dimensionless ramp rate (°C/tM), sample loading (capacity), flow mode, and column dimensions (probably related to surface area). [source] A novel HS-SBSE system coupled with gas chromatography and mass spectrometry for the analysis of organochlorine pesticides in water samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 20 2008Paula Grossi Abstract A methodology to analyze organochlorine pesticides (OCPs) in water samples has been accomplished by using headspace stir bar sorptive extraction (HS-SBSE). The bars were in house coated with a thick film of PDMS in order to properly work in the headspace mode. Sampling was done by a novel HS-SBSE system whereas the analysis was performed by capillary GC coupled mass spectrometric detection (HS-SBSE-GC-MS). The extraction optimization, using different experimental parameters has been established by a standard equilibrium time of 120 min at 85°C. A mixture of ACN/toluene as back extraction solvent promoted a good performance to remove the OCPs sorbed in the bar. Reproducibility between 2.1 and 14.8% and linearity between 0.96 and 1.0 were obtained for pesticides spiked in a linear range between 5 and 17 ng/g in water samples during the bar evaluation. [source] Capillary gas-chromatographic determination of spermidine in hair lotionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2006Veniero Gambaro Abstract Biogenic polyamines, such as spermidine (SPD, NH2,(CH2)4,NH,(CH2)3,NH2), are ubiquitous polycationic molecules which play a definitive role in many biological processes such as nucleic acid metabolism, protein synthesis, and cell growth. SPD is commonly used as an ingredient in hair lotions, because it seems to promote hair growth. This work describes a capillary GC method for quantitative determination of SPD in hair lotions using 1,6-diaminohexane as internal standard, a methyl silicone capillary column, and a flame ionisation detector. Aliquots of hair lotion were treated with an alkaline aqueous solution and internal standard was added. The emulsion was extracted with diethyl ether containing ethyl chloroformate. Ether extracts, evaporated to dryness and reconstituted in ethyl acetate, were analysed by capillary GC with flame ionisation detection. Validation took into account the specificity, linearity, precision, and accuracy of the analytical method: these parameters were valid for the quantitative determination of SPD in hair lotion. [source] | ||||||||||