气相色谱-质谱法测定茶叶中23种农药残留量

GC-MS Determination of Residual Amounts of 23 Pesticides in Tea

采用气相色谱-质谱法测定茶叶中23种农药的残留量。茶叶样品以乙腈超声提取,以复合双层固相萃取柱净化。在气相色谱分离中用HP-5MS色谱柱为固定相,在质谱分析中采用多反应监测模式。以环氧七氯为内标物。方法的检出限（3S/N）在0.003~0.02mg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在87.5%~104%之间,测定值的相对标准偏差（n=6）在1.4%~9.9%之间。

GC-MS was applied to the determination of residual amounts of 23 pesticides in tea. The tea sample was extracted ultrasonically with acetonitrile, then cleaned-up by double layer solid-phase extraction column. The HP-SMS chromatographic column was used for GC separation and the multiple reaction monitoring mode was adopted in MS determination. Heptachlor epoxide was used as internal standard. Detection limits （3S/N）of the method found was in the range of 0. 003-0. 02 mg·kg-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 87. 5%-104% with RSD＇s （n=6） in the range of 1.4 %- 9.9%.