SIMULTANEOUS QUANTIFICATION OF INSECTICIDES INCLUDING CARBARYL IN DRINKING-WATER BY GAS-CHROMATOGRAPHY USING DUAL ELECTRON-CAPTURE AND NITROGEN-PHOSPHORUS DETECTION

A rapid and simple gas chromatographic method for the simultaneous det ermination of malathion, parathion, fenitrothion, diazinon and carbary l in drinking water is presented. A fused-silica SE-54 column was used for the separation of the insecticides and was split into two specifi c detectors; electron-capture and nitrogen-phosphorus detectors by usi ng column switching. A water sample was extracted with methylene chlor ide. The organic phase was evaporated and the residue was derivatized with pentafluoropropionic acid anhydride. The detection limit was belo w 0.1 ng/ml and the calibration curves showed good linearity with r=0. 998 similar to 1.000. The method was sensitive, reproducible and simpl e enough to permit the reliable routine analysis of the pesticides in drinking water.