Abstract:

Residues of 27 kinds of common halogen-containing pesticides in tea were determined by dispersive solidphase
extraction and gas chromatography. Tea samples were extracted with acetone-hexane (l:1, V/V) and the extracts were
purified by adding anhydrous sodium sulfate, florisil and activated carbon. The purified extracts were separated on a DB-
17 capillary column, and detected with an electron capture detector (ECD). The average recovery of standard addition was
82.2%–113.4% with relative standard deviation of 1.2%–6.0% in tea samples by this method. The limit of detection for 27
kinds of common halogen-containing pesticide residues in tea was 0.005–0.075 mg/kg.

Key words: tea, pesticide residues, dispersive solid-phase extraction, gas chromatography-electron caputure detector