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

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%.