Rapid GC Determination of 10 Residual Organophosphorus Pesticides in Tea Extracts

Ten residual organophosphorus pesticides (OPhP′s) in strong tea were extracted from the sample with dichloromethane.The extract was dehydrated with anhydrous Na2SO4 and concentrated to 2.00 mL by rotary evaporation under the condition of 35 ℃ and 0.006 MPa.The sample solution was used for direct GC determination without purification,and binary capillary chromatographic columns of DB-1701 and RTX-5 and binary FPD detectors were adopted.Detection limits (3S/N) of the method for the 10 OPhP′s found were in the range of 3-10 μg·L-1.Tests for recovery and precision were made by standard addition method at 3 concentration levels,giving values of recovery and RSD′s (n=8) in the ranges of 83.3%-112.6% and 3.4%-6.9% respectively.