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

A method for determining the phenolic compounds from the hydrolysis of some organophosphorus pesticides by liquid chromatography/ electroche mical detection has been developed. A carbon fibre micro-electrode was used for the detection. Phenol, 4-nitrophenol, 3-methyl-4-nitro-pheno l, and 2,4,5-trichloropyridinol in water were analyzed by the method. The responses of the four phenolic compounds increased steadily with t he 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-meth yl 4-nitrophenol.