气相色谱测定毒死蜱前处理方法的优化

Optimization of the Pretreatment in Determination of Chlorpyrifos by Gas Chromatography

为满足检测需求,提高效率,降低成本,本文对农业部推荐使用的气相色谱法测定蔬菜和水果中有机磷类农药的前处理方法进行优化.样品和溶剂使用量较农业部NY/T 761-2008标准减少5倍,超声波提取效率高于震荡提取效率,其回收率为89%~92%,相对标准偏差(RSD)为1.40%~6.22%,检出限达0.02 mg/kg.毒死蜱的添加回收率和RSD均符合农残分析要求,表明该方法操作简单、实用,灵敏度高,可用于农药残留检测的实际工作中.氮吹浓缩程度对方法的准确度有显著影响.

The study aimed to simplify the workload in the pretreatment of determination of pesticides in vegetables and fruits.Compared with agricultural department standard NY/T 761-2008,the amounts of sample and solvent was reduced by 5-fold.The recoveries by ultrasonic extraction which ranged from 89 to 92%with a relative standard of deviation(RSD)of 1.40 to 6.22%and a limit of detection of 0.02 mg/kg were higher than by vibration extraction.The recoveries of the pesticide and the RSD accorded with the demands in the determination of pesticides,showing that this sample pretreatment method is handy,practical,sensitive and can be used in the practical work of pesticide residue detection.The concentration degree of nitrogen blowing has significant influence on the accuracy of the method.