GPC-GC Determination of Residual Amounts of 55 Organophosphorus Pesticides in Sunflower Seeds

A method of GC for determination of residual amounts of 55 organophosphorus pesticides in sunflower seeds was proposed.The sample was extracted with a mixture of ethyl acetate and cyclohexane(1 +1),and the extracts obtained were purified to remove the macromolecular impurities by gel permeation chromatography(GPC),using Bio-Beads S-X3 GPC column and the same mixture of ethyl acetate and cyclohexane(1 + 1) as mobile phase.The 55 organophosphorus pesticides in the eluate were separated on DB-1701(30 m×0.25 mm,0.25 μm)column and determined by flame photometric detector.Linear relationships between values of peak area and mass concentration of the 55 organophosphorus pesticides were kept in definite ranges,with detection limits(10S/N) in the range of 0.0025-0.05 mg ? kg~(-1).Recovery and precision of the method were tested at 3 concentration levels,giving results of recovery in the range of 53.5%-119%and RSD's(n = 6) less than 14%.