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

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.