SPME/GC-MS鉴别地沟油新方法

采用固相微萃取(SPME)气相色谱-质谱联用(GC-MS)技术,研究了油脂内源及外源物质的微量化学成分。结果发现:纯正花生油和大豆油不含反式脂肪酸,地沟油含有反式脂肪酸trans-C18∶1、trans-C18∶2;纯正花生油和大豆油中含有正己醛、正壬醛和正癸醛等杂质,而地沟油中除了这几种醛类外还含有乙酸、3-丁烯腈、2,5-二甲基吡嗪等特征杂质成分。通过测定内源性物质和外源性物质的存在,两种检测结果互相印证,综合判断,最终可确定是否为地沟油,据此首次建立了SPME/GC-MS鉴别地沟油的新方法。该方法不但可用于地沟油的鉴别,还可用于掺假食用油的检测。

A Novel Method for the Identification of Gutter Oils Using SPME/GC-MS

Chemical composition of the endogenous and exogenous substance in oils were investigated by gas chromatography-mass spectrometry(GC-MS) and solid-phase microextraction(SPME).The results indicated that pure peanut oils and soybean oil contain no trans-fatty acids,which(trans-C18 ∶1,trans-C18 ∶2)can be detected in gutter oil.At the same time,some impurities such as n-hexaldehyde,n-nonaldehyde and n-decaldehyde were detected in pure peanut oils and soybean oil,while other substances such as acetic acid,3-butenenitrile and 2,5-dimethylpyrazine can be found in gutter oils besides the above aldehydes.The existence of the endogenous and exogenous substance in oils can be used to confirm weather the oils are recycled or not,therefore a new method for the identification of gutter oils using SPME/GC-MS was established.This method can not only be used in the distinguishment of gutter oils and edible oils,but also the detection of oil adulteration.