DETERMINATION OF THE ESTER-CLEAVAGE PRODUCTS OF SOME ORGANOPHOSPHORUS PESTICIDES BY LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

A method for determining the phenolic compounds from the hydrolysis of some organophosphorus pesticides by liquid chromatography/ electrochemical detection has been developed. A carbon fibre micro-electrode was used for the detection. Phenol, 4-nitrophenol, 3-methyl-4-nitro-phenol, and 2,4,5-trichloropyridinol in water were analyzed by the method. The responses of the four phenolic compounds increased steadily with the increased working electrode potential within the potential range of 1.2 to 1.4 V. The detection limits were 0.1 ng for phenol, 0.5 ng for 2,4,5-trichloropyridinol, 1 ng for 4-nitrophenol, and 2 ng for 3-methyl 4-nitrophenol.