Simultaneous Determination of 36 Pesticide Residues in Tea by GC-MS

A gas chromatography-mass spectrometry (GC-MS) method was developed for the simultaneous detection of 36 pesticide (including 9 kinds of pyrethroid pesticides, 12 kinds of organochlorine pesticides and 15 kinds of organophosphorus pesticides) residues in tea. The method was based on accelerated solvent extraction (ASE) with a mixture of acetonitrile and dichloromethane (1:1, V/V) and gel permeation chromatography (GPC) cleanup followed by GC-MS analysis of the extracts in selected ion monitoring (SIM) mode. The external standard method was adopted for quantitative analyses. At the three spike levels of 0.05, 0.2 and 1.0 mg/kg, mean recoveries for the 36 pesticides were between 67.8% and 110.2% with a relative standard deviation (RSD) ranging from 1.72% to 8.89%. The limits of detection were between 5 μg/kg and 55 μg/kg. This method is rapid, sensitive and accurate and can meet the demands for determining pesticides in tea samples.