Determination of 44 Organophosphorous Pesticides Residual in Chestnut Using Solid Phase Extraction and On-line Gel Permeation Chromatography/Gas Chromatography-Mass Spectrometry

An analytical method has been developed for the determination of 44 organophosphorous pesticides in chestnut. With acetonitrile-water (4 : 1, V/V) as the extraction solution, the samples were extracted by means of high-speed homogenization. And the crude extract was purified by ENVI-18 solid phase extraction column to remove most fats and sterols in samples, then after on-line GPC-GC/MS analysis which further removed macromolecular interference material, such as pigment and fat, the backgroud interference brought about by the complex matrix in samples was effectively reduced. When standard addition to the samples was 0.05 mg/kg, the recovery rate for most of pesticides was from 65% to 120%, and the relative standard deviation was less then 15%. The limits of detection of 28 organophosphorous pesticides were 0.002 - 0.05 mg/kg. With the application of external standard and gas chromatography-mass spectrometry, the linear relations and the recovery results were satisfactory. Experiments showed that the method is rapid, accurate and highly senstive, and can be used for the simultaneous detemination of organophosphorous pesticides residues in chestnut.