Determination of Residue of Chlorpyrifos,Acetochlor and Butachlor in Soil by GAS Chromatography

By pretreatment improvement and recoveries test,a method for determination of chlorpyrifos,acetochlor and butachlor in soil samples,which were rapidly extracted by ultrasonic with acetonitrile as extractant,purified by solid phase extraction,concentrated by nitrogen-blowing,and determined by GC ECD detector was established.When adding chlorpyrifos,acetochlor and butachlor at concentration of 0.05mg·L-1、 0.1 mg·L-1 and 0.5 mg·L-1,the average recoveries for the chlorpyrifos were 110.7%,99.1%,96.6%,acetochlor were 96.6%,97.94%,100.5%,butachlor were 91.8%,93.0%,93.9%.The relative standard deviation of chlorpyrifos,acetochlor and butachlor ranged from 6.2% to 10.3%,7.9% to 10.4% and 5.9% to 9.6%.The limits of detection were 0.0008mg·kg-1,0.0036mg·kg-1 and 0.0029mg·kg-1,respectively.The method is accuracy,precision and reproducibility,which meet the requirement of pesticide residue testing.