SPE-GC Determination of 11 Residual Organophosphorus Pesticides in Tea with Capillary Chromatographic Column

Eleven residual organophosphorus pesticides in tea were extracted from the sample ultrasonically with acetonitrile and the pesticides in the extract were enriched and purified by SPE on ODS-C18 column.Methanol was used as eluant and the residual pesticides in the eluate were separated on the HP-5 capillary column and determined by gas chromatography with nitrogen-phosphorus detector.Linear relationships were obtained for the eleven pesticides in definite concentration ranges.Recovery and precision of the method were tested giving values of recovery in the range of 85.3%-100.6%,and values of RSD′s(n=7) in the range from 3.5% to 8.4%.Nine tea samples were analyzed by the proposed method and results were given in detail.