GC-MS法测定食品中胆固醇含量的研究

目的:建立一种简单、快速而又重现性好的胆固醇测定方法,以监测食品中胆固醇的确切含量。方法:饼干样品经石油醚萃取后用50% KOH-乙醇（40:12）皂化后用乙醚二次萃取,上层溶液水洗至中性后无水Na2SO4脱水过滤并浓缩至1ml,氮气吹干后用正己烷溶解,注入GC-MS进行定量分析。研究结果显示,该方法胆固醇的回收率在96．64%～100．13%之间,平均值为98．43%。方法的精密度高,重现性好,标准偏差S=0．02193,相对标准偏差RSD（n=6）=1．4393%,最低检测限为0．0659μg/ml,最小定量限为0．22μg/ml:若以称样量0．5g计算,方法的最低检测限为1．318μg/g。

Determination of Cholesterol Content in Cookies by Gas Chromatography-Mass Spectrometry

Aim:To set up a simple,high-speed,and repeatable method used for determining cholesterol content in food samples, to benefit the people to control the intake of cholesterol.Method:The cookie samples were extracted with petroleum ether first, and the extraction was saponified with 50% KOH-ethanol（40:12）solution.Then the saponified solution was extracted again with ether.The upper solution was washed to neutral with distilled water and was dehydrated with anhydrous Na2SO4N.The dehydrated solution was filtered and concentrated to about 1ml and then blowed to dry with N2.The dried remains were dissolved with n-hexane and were quantitatively analyzed with GC-MS.Result:The result showed that with this method,the recovery of cholesterol is about 98.43%;the standard deviation 2.193%,and RSD（n=6）1.4393% with the minimum detection limit 0. 0659μg/ml and the minimum ration 0.22μg/ml.Conclusion:This method can be applied to determine the cholesterol content in different food samples.