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研究了一种大鼠粪样中Ｃ＿１～Ｃ＿６脂肪酸在室温下乙酯化的气相色谱分析方法，酸化的大鼠粪匀浆用乙醚－石油醚（１＋１）振摇提取，提取液中的短链脂肪酸与四甲基氢氧化铰生成的季铵盐在二甲基乙酞胺溶剂中，于室温下与溴乙烷反应生成相应的乙酯。采用１０％丁二酸乙二醇聚酯色谱柱，火焰离子化检测器测定Ｃ＿１～Ｃ＿６脂肪酸乙酯。大鼠粪样中待测脂肪酸的提取效率为８８．５％～１００．０％，加标回收范围为８２．４％～１１０．８％，变异系数为３．２％～１０．９％。对２ｇ样品，各脂肪酸的检出限均可达１ｐｐｍ。本文探讨了乙酯化反应的最佳条件，样品中Ｃ＿１～Ｃ＿６脂肪酸的衍生化反应在室温下１小时即可定量完成。所用试剂安全，操作简便，对实际样品的分析表明，本法适用于粪样中短链脂肪酸的测定。
A gas chromatographic method was developed for the esterification of C 1 -C 6 fatty acids in rat fecal samples at room temperature. The acidified rat feces homogenates were extracted by shaking with ether-petroleum ether (1 + 1) Quaternary ammonium salts of fatty acids and tetramethylhydroxylate are reacted with ethyl bromide at room temperature with ethyl acetate to form the corresponding ethyl ester. The C 1 -C 6 fatty acid ethyl ester was determined by flame ionization detector with 10% succinate glycol polyester column. The extraction efficiencies of fatty acids in the rat feces samples ranged from 88.5% to 100.0%, spiked recoveries ranged from 82.4% to 110.8%, and the coefficients of variation ranged from 3.2% to 10.9%. For 2g samples, the detection limit of each fatty acid can reach 1ppm. In this paper, the optimum conditions of ethyl esterification were discussed. The derivatization reaction of C 1 -C 6 fatty acids in the sample can be done quantitatively at room temperature for 1 hour. The reagents used are safe and easy to operate. The analysis of actual samples shows that this method is suitable for the determination of short chain fatty acids in fecal samples.