GC Determination of Residual Amount of Pyrethroid Pesticides in Whitebait with Separation by Dispersive Solid Phase Extraction

Six pyrethroid pesticides,namely bifenthrin,fenpropathrin,cyhalothrin,cypermethrin,fenvalerate and deltamethrin,in whitebait were determined simultaneously by GC with ECD after separation by dispersive solid phase extraction (DSPE).Sample of whitebait was extracted homogeneously with glacial acetic acid-acetonitrile solution as dispersion agent.The extract obtained was purified by DSPE through cycle-shaking with ethylene diamine-N-propylsilane (PSA),C18 and graphitized carbon black.The supernatant was used for GC-ECD analysis.Linearity ranges found were in the same range of 0.05-1.0 mg·L-1 for the 6 pyrethroid pesticides.Detection limits (3S/N) of the method obtained were 0.01 mg·kg-1 for cypermethrin and 0.02 mg·kg-1 for the other 5 pyrethroid pesticides.Tests for recovery and precision were made by addition of standard solutions of the 6 pyrethroid pesticides with 2 different concentrations to whitebait sample which was then analyzed by the proposed method.Values of recovery obtained were in the range of 82.9%-106.1% and values of RSD′s (n=6) were in the range of 2.9%-7.1%.