Simultaneous determination of multi residues of organochlorine and pyrethroid pesticides in vegetables and their products by gas chromatography with dual tower and dual column

A method for the determination of 16 organochlorine and 8 pyrethroid pesticide residues in vegetables and their products by gas chromatography was established.The samples were extracted by acetone+hexane(1+1) and partitioned into hexane with 2% Na2SO4.The extractant were cleaned up on a silicon-magnesium adsorbent column and separated with DB-1701 and DB-5 capillary columns with two GCuECD detectors.Recoveries are 79.8%～118.7% and 85.6%～118.8%,respectively.Relative standard deviations are 2.1%～9.2% and 1.8%～8.6%,respectively. The detection limits are 0.001 mg/kg for organochlorine pesticides,0.002 mg/kg for bifenthrin,fenpropathrin and cyhalothrin,and 0.005 mg/kg for the other pyrethroid pesticides.