基于固相微萃取技术的GC-MS法快速检测地沟油

Determination of waste cooking oil by activated carbon fiber-solid phase microextraction coupled to GC-MS

ACF-SPME与GC-MS联用,优化的测定地沟油的最佳条件为:称取0.025g样品,加入0.005g Na2SO4,在120℃下萃取50 min,色谱解析1 min。实验发现不同来源的地沟油和不同品牌的植物类食用油均可以检测到2-十九烷酮,且地沟油中的含量远高于植物油;所有油类均含有庚醛,其含量与其他物质成比例增加或减少。提出用M值指标来判断地沟油的方法。即M=(H2/H1)2,其中H2表示2-十九烷酮的峰高,H1表示庚醛的峰高。结果表明:不同品牌植物油的M值均低于40,而地沟油远高于40,最高可达339.07。M值法适用于泔水油来源的地沟油的判断。

It is great significant to find an efficient and effective method to detect the illegal waste cooking oil, which cause serious damage to people＇s health. In this article, a method for the determination of waste cooking oil based on ACF-SPME and GC-MS was developed. The optimum extraction determination was as follows： 0. 025g of sample was added 0. 005g of Na2SO4, conditions of waste cooking oil and extracted at 120 ℃ for 50min, and the desorbed for 1 min. The waste cooking oil from different sources and different brand of plant oilunder optimal conditions was determined. The results are that 2-nonadecane ketoneand heptanal can be detected in all oils, and it is found that the contents of 2-nonadecane ketone in drainage oil is much higher than that in plant oil ; the contents of heptanal and other materials are proportional to we put forward the M value to judge the illegal waste cooking oil. The formula is the increase and decrease. Then as follows ： M = （ H2/H1 ） 2, H2 means the peak height of 2-nonadecane ketone, H1 means the peak height of heptanal. The results show that the M value of different brands of plant oil are all lower than 40, while waste cooking oil is much higher than d0, up to 339. 07. After the further experiments and analysis, we find the M value of peanut oil which is after repeated heating and frying oil is the same as that of the unused plant oil. The M value of lard oil is lower than that of the waste cooking oil, but still higher than that of the plant oil. Therefore, we draw the conclusion that 2-nonadecane ketone in the used, and is analyzing the swill oil.