气相色谱法测定蔬菜中多农药残留

DETERMINATION OF MULTIRESIDUE OF PESTICIDES IN VEGETABLE BY GAS CHROMATOGRAPHY

应用气相色谱法测定蔬菜中的有机磷和拟除虫菊酯多农药残留。采用Ｖ（丙酮）∶Ｖ（水）＝１∶１（包括蔬菜中的水分含量）的混合溶剂同时提取出１６种农药残留，用二氯甲烷、石油醚分别对提取液进行液液分配后除去提取液中的水相和水溶性杂质；再采用酸洗活性炭除去提取液中的叶绿素、胡萝卜素等杂质，最终得到纯净的有机磷、拟除虫菊酯农药残留提取液，供气相色谱仪测试。色谱条件中选用了中等极性的固定相ＯＶ１７配之以一阶温度程序，使１０种有机磷农药分离良好，选用了弱极性的ＯＶ１，在恒温条件下使６种拟除虫菊酯农药分离良好。各农药添加回收率为８００％～１０４％，变异系数１９１％～９９０％，最小检出浓度０．００２～０．０３ｍｇ／ｋｇ。

A GC method to determine multiresidue of organophosphorus and pyrethroid pesticides in vegetable was established. A solvent of V (acetone)∶ V (water)=1∶1 was used to extract multiresidue of 16 pesticides simultaneously. Dichloromathane and petroleum ether were used for liquid liquid partitioning to remove aqueous phase and a part of impure material. Chloropylls and carotenes were cleaned with acid washed active charcoal. Multiresidue of organophosphorus pesticides was separated on a column of medium polar stationary phase OV 17, with a one step temperature program. While multiresidue of pyrethroid pesticides was separated on a column of weak polar stationary phase OV 1, with constant temperature. The recoveries of pesticides ranged from 80.0% to 104%, C.V. from 1.91% to 9.90% and MDC from 0.002 mg/kg to 0.03 mg/kg.