硫酸催化甲酯化气相色谱法测肥皂产品中的脂肪酸分布及总脂肪物含量

Determination of Fatty Acid Distribution and Total Fatty Matter Content in Soaps by Gas Chromatography with Sulphuric Acid Catalysed the Methyl Esterification of Fatty Acids

气相色谱法-FID检测器测定产品的脂肪酸分布及平均分子量。用硫酸催化甲酯化肥皂产品中的脂肪酸,红外光谱法定性监测甲酯化产物。采用正己烷提取并富集甲醇溶液中的反应产物。采用外标法定量。用标准加入法测得方法的回收率在93.4%～103.8%之间,相对标准偏差(n=6)在3.6%～5.1%之间。用气相色谱测试数据计算推导可以获得肥皂中的总脂肪物含量。

A method to determine fatty acid distribution and average molecular weight of soap products by gas chromatography method with FID detector has been developed in this paper.Sulfphuric acid was used as catalyst to methyl esterified fatty acids.Infrared spectroscopy method was used to monitor the resultant of reaction.The reaction product was separated from methanol solution and enriched by extraction with n-hexane.External standard calibration was adopted in the determination.The method was tested,giving values of average recovery range from 93.4% to 103.8% and RSD＇s（n=6） range from 3.6% to 5.1%.And the total fatty matter content was calculated by the data obtained from GC.