GC Determination of Residual Propargite and Pyridaben in Tea

Gas chromatography was applied to the determination of residual propargite and pyridaben in tea.Propargite and pyridaben in tea sample were extracted with acetone and back-extracted with n-hexane.The hexane extract was passed through a purifying column packed with florisil.Propargite was eluted from the column with eluant A n-hexane mixed with ethyl ether in the ratio of 8 to 2 and determined by FPD.And then pyridaben was eluted with eluant B n-bexane and ethyl ether mixed in the ratio of 5 to 5 and determined by ECD.External standard curve method was used in the determination.Values of recovery for propargite obtained were in the range of 84%-102%,when tested with addition of standard propargite in the concentration levels between 0.5-10 mg·kg-1,and values of RSD′s (n=6) found were less than 5%.The detection limit of this method was 0.5 mg·kg-1.Values of recovery for pyridaben tested with addition of standard pyridaben in the concentration levels between 0.01-0.5 mg·kg-1,were found to be from 90% to 103%,and values of RSD′s (n=6) found also less than 5%.The detection limit of this method was 0.01 mg·kg-1.