Determining of Chlorpyrifos Residue in Fresh Peach by GC-ECD

A method was established for determining of residue of chlorpyrifos in fresh peach by GC-ECD.The sample was extracted with acetonitrile,liquid-liquid distribution with n-hexane and water and cleaned up with silica gel.The sample was separated in the quartz elastic capillary column DB-1701P with N2(99.997%) as carrier gas.The limit of detection was 0.001 mg·kg-1.As the samples were fortified with chlorpyrifos at concentrations of 0.05 mg·kg-1 and 0.5 mg·kg-1,the recoveries were 88 % and 90 %,and the RSD was 12.63 % and 11.92 % respectively.This method is sensitive and accurate,so it is suitable for the determining of trace chlorpyrifos in fresh peach.Final results of the peach from some farmer markets and supermarkets of Qingdao show that it was below the detection of limit in plastic houses,while it was detected in the field,and the residues were 0.001 0-0.416 1 mg·kg-1 and it is below the MRLs of CODEX(0.5 mg·kg-1).