固相萃取-气相色谱双检测器法测定蔬菜中26种有机磷农药残留量

Analysis of twenty-six organophosphate pesticides in vegetable by gas chromatography with two detectors coupled with solid phase extraction

目的建立一种同时测定蔬菜中有机磷农药残留量的分析方法。方法以乙腈为提取剂,以CARB/NH2柱净化,以丙酮/乙腈混和溶剂作为净化剂洗脱。用气相色谱(GC/FPD和GC/NPD)测定,以标准物质保留时间定性,以外标法定量。以低限加标样品的3倍信噪比确定方法的检出限,以3个添加水平测定样品的回收率和相对标准偏差(RSD)。结果该方法的检出限达到μg/kg水平;除敌敌畏以外,大多数农药的加标回收率在75%～120%之间,RSD均低于10%,r2>0.9981。结论该方法简便、灵敏、快速,能够满足同时测定蔬菜中多种有机磷农药残留量的要求。

A new analytical method was developed to simultaneously determine organophosphate pesticide residues in vegetable.First,the solvents for extraction were selected by comparing acetonitrile with acetone/ dichloromethane,acetone/ petroleum ether,acetone/acetonitrile.The extraction efficiency with acetonitrile was the best.Second,clean-up was performed by solid phase extraction using a CARB/NH2 cartridge.Acetone/acetonitrile had the best performance used as cleaning-up.The prepared sample was analyzed using gas chromatography（detector FPD and detector NPD）.The pesticides were identified with retention time,and they were quantified based on extract of spiking standards in a blank sample.The limits of detection were evaluated on the values of the lower concentration fortified sample under the signal-to-noise ratio of 3∶1.The recoveries and relative standard deviations RSDs were checked by adding pesticide standard solution at three levels to untreated samples.The LODs were at μg/kg level.The average recoveries of most pesticides were from 75% to 120%.The RSDs were less than 10%.These results indicated that this method is simple,rapid,and sensitive for the simultaneous determination requirements of multiple organophosphorus pesticide residues in vegetable.