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0.003~0.02 mg·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-5MS 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%.