气-质联用法测定食品中N-二甲基亚硝胺方法的改进

Improvement for Determination Method of N-dimethylnitrosamine in Food by Gas Chromatography-Mass Spectrometry

本文采用QuEChERS前处理技术,建立了一种测定食品中N-二甲基亚硝胺含量的方法。该方法采用乙腈为提取试剂,振荡和超声提取后在-18℃下冷冻3 h,离心后,上清液经QuEChERS填料净化,采用气-质联用仪(Gas Chromatography-Mass Spectrometry,GC-MS)测定。结果表明,在该试验条件下,N-二甲基亚硝胺在0.01~0.20μg·mL^(-1)线性良好,相关系数r为0.9995,方法检测限为0.15μg·kg^(-1),加标回收率为83.8%~101.2%,相对标准偏差为1.6%~5.3%。该方法操作简单方便、可批量操作,适用于食品中N-二甲基亚硝胺含量的测定。

A method for the determination of N-dimethylnitrosamine in food was established by QuEChERS pretreatment technology.In this method,acetonitrile was used as extraction reagent.The samples were extracted by oscillation and ultrasonic,and then frozen at-18℃for 3 h.The supernatant was purified by QuEChERS filler after centrifugation,and then determined by gas chromatography-mass spectrometry.It showed that the linearity of N-dimethylnitrosamine was good in the range of 0.01~0.20μg·mL^(-1),the correlation coefficient(r)was 0.9995.And the detection limit was 0.15μg·kg^(-1),the recovery of standard addition was 83.8%~101.2%,and the relative standard deviation was 1.6%~5.3%.In conclusion,the established method is simple,convenient,and can process samples in batches,which is suitable for the determination of N-dimethylnitrosamine in food.