气相色谱电子捕获法检测地下水中5种残留农药

Determination of Chlorothalonil,Propiconazole,Hexaconazole,Azoxystrobin and β-Cypermethrin in Groundwater by Gas Chromatography with Electron Capture Detector

用气相色谱-电子捕获法(GC-ECD)检测地下水中百菌清、丙环唑、己唑醇、嘧菌酯和高效氯氰菊酯。样品用乙酸乙酯-正己烷(体积比1∶1)液-液提取,提取液经无水硫酸钠去水后、浓缩、并定容至1.0 mL,最后用微池-电子捕获检测器(GC-μECD)进行检测。方法准确度、灵敏度高。2.0 ng/L添加水平所有待测物回收率≥68.8%,相对标准偏差(RSD,n=3)≤14.6%,百菌清、己唑醇、丙环唑、高效氯氰菊酯和嘧菌酯的方法检测限分别为0.50 ng/L、2.0 ng/L、2.0 ng/L、2.0 ng/L和2.0 ng/L。

A Method for the determination of pesticide residues of chlorothalonil,propiconazole,hexaconazole,azoxystrobin,and beta-cypermethrin in groundwater was described in this paper.The sample was extracted by mixture of ethyl acetate and hexane（1∶1,V/V）,and after dehydration with anhydrous sodium sulfate,concentration and fixing sample volume to 1.0 mL,the 5 pesticide residues were determined directly by gas chromatography with electron capture detector（GC-μECD）.The detection limits of the method for chlorothalonil,propiconazole,hexaconazole,azoxystrobin,and beta-cypermethrin were 0.50 ng/L,2.0 ng/L,2.0 ng/L,2.0 ng/L and 2.0 ng/L,respectively.The recoveries for all the analytes at 2.0 ng/L addition level were above 68.8 % with precision of 14.6 % RSD（n=3）.The method has the advantages of high sensitivity and accuracy.