| A microwave assisted extraction and gas chromatographic(MAE/GC）method was established for the simultaneous determination of 14 organochlorine pesticides,including the four isomers of DDT and BHC,pentachloronitrobenzene(PCNB）,tetrachloronitrobenzene,tetrachloroaniline,pentachloroaniline,procymidone and methyl 5 chlorophenyl sulfide(MPCPS）in starch.The samples were extracted with n hexane-dichloromethane mixed solvent(1∶2,by volume）.The extract was purified with a Florisil column using n hexane-dichloromethane(1∶5,by volume） as elution solvent.Experimental conditions were optimized,and three different extraction methods of ultrasonic extraction,microwave assisted extraction and soxhlet extraction were compared.Extraction conditions were studied by the orthogonal test.Under the optimal conditions,the calibration curves showed good linearities in the range of 20-200 μg/kg for 14 organochlorine pesticides.The recoveries of 14 organochlorine pesticides at spiked levels were in the range of 68%-108%.The detection limits ranged from 0.1 μg/kg to 0.3 μg/kg and the quantitation limits ranged from 0.5 μg/kg to 0.8 μg/kg.The method was easy to operate,rapid，accurate and sensitive,and was suitable for the determination of organochlorine pesticides residues in starch sample. |