Rapid and sensitive determination of 4-nitrophenol, 3-methyl-4-nitrophenol, 4,6-dinitro-o-cresol, parathion-methyl, fenitrothion, and parathion-ethylby liquid chromatography with electrochemical detection

Liquid chromatography with electrochemical detection has been used to deter mine various nitropesticides, DNOC, fenitrothion, and parathion (methyl and ethyl), and some of their main metabolites, 4-nitrophenol for parathion (m ethyl and ethyl) and 3-methyl-4-nitrophenol for fenitrothion, by using indi rect detection. Analysis of them in river water samples has been performed without a preconcentration step. The recovery efficiencies of the tested co mpounds yielded values between 96 and 112% at the fortification level of 0. 5 ppb in a river water sample, and their relative standard deviations were between 1 and 15%. The detection limits of these compounds ranged between 0 .05 and 0.14 ppb.