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171.
Summary Diaromatics are geochemically significant constituents of crude oils. Their determination is usually achieved by elaborate prefractionation methods, such as medium pressure liquid chromatography and HPLC, prior to capillary gas chromatography. The present contribution describes the quantitative analysis of methylnaphthalenes, ethylnaphthalenes, and dimethylnaphthalenes in selected crude oils by two-dimensional capillary GC. Since the method does not comprise any work-up procedure the determination of geochemical parameters (alkylnaphthalene concentration ratios) is performed on the original, untreated crude oil samples. Accordingly, the analytical results reflect the original composition. The influence by evaporational losses in the laboratory is minimized. 相似文献
172.
Summary A derivatization procedure for the gas chromatographic analysis of bifunctional amines likeβ-adrenergic blocking drugs is described. The method consists of a two-step reaction with methyldichlorophosphine and sulfur
in presence of triethylamine to form cyclic methylphosphonothioic derivatives. The properties of these compounds are discussed
and the application of the method to the quantitation of ephedrine in human body fluids is presented.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
173.
V. G. Berezkin V. R. Alishoyev E. N. Victorova V. S. Gavrichev V. M. Fateeva 《Chromatographia》1982,16(1):126-131
Summary The use of crystallohydrates, crystallohydrate solutions and melts as stationary phases in gas chromatography has been proposed. Crystallohydrates have been shown to display high selectivity in the separation of polar organic compounds when use is made of water vapours as the mobile phase. Some aspects of gas-liquid chromatography in water vapours and with the stationary phase comprising crystallohydrates have been studied, and the preliminary results obtained point to the desirability of further progress in this field.Presented at the 14th International Symposium on Chromatography London, September, 1982 相似文献
174.
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177.
E. L. Anderson M. M. Thomason H. T. Mayfield W. Bertsch 《Journal of separation science》1979,2(6):335-342
A versatile two-dimensional gas chromatograph is described, consisting of 2 separate ovens, one intermediate trap, an auxiliary inlet, and the necessary hardware to effect off-line switching according to the principle of Deans. The unit has been designed for use with high resolution glass capillary columns. The performance of individual instrumental components was critically evaluated. Results showed that low dead volume glass to metal connections were required in the manifold and detector lines to minimize extra-column effects. The mass of the intermediate trap must be low to allow rapid heating. Operational parameters are discussed and examples of some applications are shown. 相似文献
178.
国内气相色谱近年的进展 总被引:17,自引:0,他引:17
本文对近三年国内学者在气相色谱方面的研究和应用作了综述 ,国内学者的研究基本和国际上气相色谱方面的研究类似 ,在全二维气相色谱、快速气相色谱 ,微型气相色谱仪、新型气相色谱固定相和色谱柱的溶胶 凝胶涂渍技术领域的研究方面作出了贡献。有关气相色谱的应用研究中 ,介绍了大量在药物分析、食品分析、环境分析、石油和石化分析和化工产品及高聚物分析等领域中应用的题目和摘要 相似文献
179.
Gas Chromatographic Method for Routine Determination of Oleanolic and Ursolic Acids in Medicinal Plants 总被引:1,自引:0,他引:1
Summary A rapid and simple gas chromatographic method has been established for routine analysis of free oleanolic and ursolic acids in dried samples of medicinal herbs. Soxhlet extraction of triterpenes was followed by solid-phase extraction (SPE). Amounts of the compounds were measured by gas chromatography after silylation of the purified samples. Experiments were performed to establish the optimum conditions (e.g. solvent, and mode and duration of extraction) for calibration curve linearity, sensitivity, reproducibility, and recovery. The conditions used for derivatization and gas chromatographic analysis resulted in an improvement on literature data. The method devised enables accurate routine measurement of many samples in quite a short time (e.g. for chemotaxonomical screening, or quality control of herbal drugs). The practical application of the method was illustrated on five Lamiaceae species. 相似文献
180.
建立了气相色谱过程的动态数学模型,给出了模型的实用算法,并据此对各种操作条件下的色谱流出曲线进行了动态模拟计算。模拟计算结果表明该模型是有效的,能够用于各种程序控制的色谱过程,可得到色谱分离的优化条件。 相似文献