Determination of 9 residues in tea by gel permeation chromatography and gas chromatography.

A novel method was established for determination of S-421,organic-chlorine and pyrethroid pesticide residues in tea by gas chromatography with electric capture detector(GC-μECD).After ultrasonic extracted with acetone-petroleum ether(1∶1,V/V),the extraction was purified with gel permeation chromatography(GPC) column,then the samples were detected with GC-μECD.The limits of detection of this method ranged from 0.002 to 0.060 μg·mL-1.The recoveries of pesticides from tea ranged from 69.2% to 101.7% and the RSDs of recoveries were almost less than 15%.Therefore,this method can satisfy the requirements for the analysis of pesticide residues in the tea samples.