GC Determination of Residual Endosulfan in Grains with Separation by Accelerated Solvent Extraction

Sample of grain was crushed and extracted with acetone under static condition at 80 ℃ for 5 min.The endosulfan pesticides (mainly the α-endosulfan,β-endosulfan,acetate of endosulfan,propyl ester of endosulfan and sulfate of endosulfan) were dissolved in the organic phase and separated from the grain matrix.The extract was evaporated to near dryness by rotary evaporator.The residue was dissolved with petroleum ether and purified by solid phase extraction.The SPE column was rinsed with mixed solvent of petroleum ether and acetone (9+1),and the eluate collected was evaporated to near dryness,and the residue was taken up with petroleum ether and used for GC analysis after separation on DB 1701 capillary column.The μ-ECD detector was used for the determination.Lower limit of determination (10S/N) for the 5 pesticides were found in the range of 0.82-1.75 μg·kg-1,and values of RSD′s (n=5) found were in the range of 6.80%-10.23%.Values of average recovery found by standard addition method were in the range of 88.9%-99.1%.