Abstract: A solid-phase extraction and gas chromatographic method was established to simultaneously determine 21 organochlorines, pyrethroids and polychlorinated biphenyls (PCBs) in tea. Tea samples were extracted with hexane-acetone (1:1, V/V) in an ultrasonic bath and cleaned up on an Envi-Carb/NH2 SPE column. The analytes were separated on a RTX-5 capillary column and detected in 63Ni-ECD (electron capture detector). The recoveries for the analytes were from 68.64% to 125.62% with a relative standard deviation (RSD) from 1.05% to 12.78% at the spike levels of 0.02, 0.05 mg/kg and 0.3 mg/kg. The limits of detection (LOD) of the method ranged from 0.0022 to 0.0129 mg/kg. In conclusion, this method can be suitable for the determination of organic contaminants in tea samples.

Key words: tea, pesticides, polychlorinated biphenyls (PCBs), solid-phase extraction (SPE), gas chromatography-electron caputure detector (GC-ECD)