摘要:

AbstractHydrocarbons and metabolites from biodegradation in soil have been isolated and separated using Soxhlet extraction, withn‐heptane and dichloromethane, combined with solid‐phase extraction on silica gel and basic aluminum oxide usingn‐pentane, dichloromethane, methanol, and sulfuric acid – methanol as eluents. This procedure can be used for determination of metabolites both in laboratory‐prepared soil samples containing mineral oils and in actual contaminated soil.After microbiological degradation, organic acids and ketones which were not original components of the diesel fuel and lubricating oil contaminating the soil samples were identified using capillary gas chromatography – mass spectrometry in batch‐soil experiments. Predominantly alicyclic and branched‐chain aliphatic organic acids and diacids, and aromatic ketones, were found to be formed after a few we

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractVolatile aromatic and halogenated hydrocarbons are determined in water and soil samples by equilibrium headspace gas chromatography. Simultaneous analysis is carried out in a dual column/dual detector arrangement with ECD and PID. Their determination in contaminated soil is performed with the same instrumental configuration. However, in contrast to water analysis, an increased sample temperature was found necessary for highly adsorptive soil specimens. At sample temperatures of 95 °C, recoveries near 100% have been found. Both adsorption and desorption processes were found to be strongly time‐depende

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe unsaponifiable lipid fractions extracted from Arabica and Robusta coffee samples were analyzed by high resolution gas chromatography (HRGC) in a polar column with a thermally stable stationary phase (TAP, Chrompack). Certain characteristic ratios among diterpenic alcohols were found to permit measurement of the amount of Robusta blended with Arabica coffee, given a minimum content of 5–10%. Determination does not appear to be influenced by geographic origin of produce or even by decaffeinatio

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe separation and analysis of furan fatty acids and other minor component fatty acids present at very low concentrations in complex sample matrices, such as fish oil or lipids derived from liver and testes, require several pre‐analytical separation steps if single column gas chromatography is to furnish sufficient resolution: after extraction and transesterification hydrogenation, urea complex precipitation and argentation TLC have been applied prior to GC analysis of furan fatty acids.By using multidimensional GC‐MSD with cooled injection and flow‐controlled column switching with intermediate cold trapping, it has been possible to identify directly the methyl esters of furan fatty acids without further pre‐analytical separation.The most common of the furan fatty acids can be subdivided into two groups depending on whether they bear a propyl or pentyl side group in the 5‐position of the furan ring. In addition to the eight furan fatty acids known to be present in fish oil, six new ones were identified, four with propyl substitution and two with pentyl substitution. Four have earlier been reported to be present in the hepatopancreas of crayfish and in fish tissue, whereas the propyl‐substituted 16,19‐epoxy‐17,18‐dimethyldocosa‐16,18‐dienoic acid and the pentyl‐substituted furan fatty acid 6,9‐epoxy‐7‐methyltetradeca‐6,8‐d

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe application of a new method, computer‐controlled on‐line HPLC‐HRGC, to the analysis of the components of sweet orange oil has enabled the determination of aldehydes without interferences. HPLC was used to separate the oil aldehydes into three fractions, aliphatic aldehydes, sesquiterpene aldehydes, and monoterpene aldehydes. These fractions were transferred automatically to the GC, where the individual aldehydes were separated into well resolved chromatographic

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA number of sesquiterpene hydrocarbons commonly occurring in essential oils has been prepared as racemic mixtures by chemical synthesis. Preparative gas chromatography with selectively per‐O‐alkylated cyclodextrins has been employed for the isolation of enantiomeric mixtures or pure enantiomers from the essential oils of higher plants and liverworts (Hepaticae). The enantiomers of α‐curcumene, α‐ and β‐bisabolene, β‐elemene, δ‐elemene, α‐copaene, δ‐cadinene,cis‐ andtrans‐calamenene, and bicyclogermacrene could be resolved by enantioselective gas chromatography on capillary columns coated with cyclodextrin derivatives. The enantiomeric composition of these sesquiterpene hydrocarbons in various e

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA method has been developed for separation of linolenic acid and its seven isomers by HPLC on a silver‐ion‐loaded column. The standard 18:3 isomers, isolated from a heated linseed oil or prepared by isomerization of linolenic acid, were converted into phenacyl esters and detected by UV at 238 nm. The use of low temperature (10 °C) combined with a gradient of dichloromethane and methanol enabled separation of all thecis/transisomers. The peaks were identified by comparison of ECL values with those of a standard mixture, by chromatographing collected HPLC fractions on a polar GC column. HPLC quantification was compared with GC analysis. There was satisfactory agreement between the tow methods. This method could be used for seperation, collection and quantification of 18:3 fatty acids withtransdouble bonds in different oils and f

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe influence of a number of factors, such as the nature of the buffer, the presence of additives therein, the manufacturing conditions, and the pretreatment of the capillary, on the magnitude and repeatability of the electroosmotic flow (EOF) in silica capillary tubes has been investigated. It was established that the nature of the buffer plays the most significant role in respect of the stability and magnitude of EOF, whereas the conditions used for manufacture and pretreatment of the tubing are less important. The EOF obtained using buffers consisting of tris(hydroxymethyl)aminomethane and ethylenediamine was more repeatable than that obtained using pure phosphate buffers. Buffer additives such as sodium dodecylsulfate, 1‐butanol, sodium salts of 1‐pentanesulfonic acid and 1‐heptanesulfonic acid, altered the magnitude of the EOF only, not its repeatab

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ratio of the responses of two different specific detectors to a single compound has, when used in conjunction with the compound's retention index, been investigated as an identification criterion for the compound. The ECD:NPD and ECD:FPD response ratios have been used for the identification of some pesticides. Analyses were performed with a single column – dual parallel detection – personal computer system.The reliability of the detector response ratio (DRR) was demonstrated by the consistency of detector response with time, and the influence of the quantity of analyte and of the chromatographic operating conditions. These factors were selected in the expectation that the technique could be used for routine trace analy

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractTheoretical procedures have been used to predict linear temperature‐programmed retention indices for polycyclic aromatic compounds. It is possible to calculate such indices for polycyclic aromatic compounds in some practical situations in which the compounds cannot be eluted during a simple linear temperature program. The theory has been tested for a number of polycyclic aromatic hydrocarbon (PAHs) in single‐ and multi‐plateau temperature‐programmed gas chromatography with SE‐52 as the stationary phase. This method will extend the applicability of linear retention indices for the identification of the isomers of polycyclic aromatic

ISSN:0935-6304    

DOI:10.1002/jhrc.1240170511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY