非正常食用油鉴别新方法(一):三种辣椒碱残留量的液相色谱-质谱分析

A novel method for the identification of illegal cooking oil(1):detection of three capsaicinoids with liquid chromatography-mass spectrometry

非正常食用油(俗称地沟油)是我国食品安全领域亟须解决的问题。准确可行的地沟油检测方法被分析工作者广泛关注。由于国人的饮食习惯,辣味调料在餐饮业应用广泛,而辣椒碱是引起辣味的主要化学物质,因此可作为鉴别地沟油的潜在指标。本文采用固相萃取-液相色谱-串联质谱技术,建立了食用油中3种微量辣椒碱(辣椒素、二氢辣椒素及壬酸香草酰胺)的检测方法。首先用20 g/L氢氧化钠水溶液提取油样中的辣椒碱,再将提取液用C18小柱富集净化后进行液相色谱-质谱检测。用该法对国家食品安全风险评估中心提供的67个盲样进行了分析,结果表明辣椒碱是一个良好的地沟油特征指示物。凭借这3种辣椒碱指标,阳性样品正确识别率达到75%,阴性样品正确识别率达到100%。目前本方法已经成为国家卫生部最新公布的4种地沟油仪器检测方法之一。

Illegal cooking oil（ICO,also named swill-cooked dirty oil） has recently become a serious food safety problem in China.Now,the identification method of ICO is also a hot research area.Owning to the special eating habits of Chinese people,cayenne is widely used in catering business.Capsaicinoids are main spicy compounds in cayenne.So,they are potential evaluation indices for the identification of ICO.In this study,a solid phase extraction-liquid chromatography-mass spectrometry（SPE-LC-MS） method has been developed to detect the trace residues of three capsaicinoids（capsaicin,dihydrocapsaicin and nonylic acid vanillylamide） in cooking oil.The oil sample was first extracted with 20 g/L sodium hydroxide,the C18 SPE cartridge was then used to clean-up the sample and enrich the analytes before the liquid chromatography-mass spectrometry（LC-MS） detection.With this method,sixty seven blind samples provided by China National Center for Food Safety Risk Assessment were analyzed.The results showed that the capsaicinoids are good evaluation indices for the identification of ICO.In all the 48 ICO samples,36 samples were successfully recognized.All the 19 normal oil samples were accurately identified.This method has been chosen and authorized as one of the four standard instrumental identification methods for ICO by the National Ministry of Health of China.