ELECTROCHEMICAL DETERMINATION OF CARBARYL OXIDATION IN NATURAL-WATER AND SOIL SAMPLES

An electrochemical method for the determination of carbaryl, after pri or oxidation of 1,4-naphthoquinone in natural water and soils is repor ted. The coulometric oxidation of carbaryl at a platinum electrode was studied using 0.024 mol/L Britton-Robinson buffer (pH 7.0). The reduc tion of the oxidation product 1,4-naphthoquinone at a dropping mercury electrode was used for the indirect determination of carbaryl after s eparation on C18 Sep-pak cartridges by differential pulse polarography (detection limits: 0.41 mg L-1 of water and 0.47 mg kg-1 of soil) and directly without separation by adsorptive stripping voltammetry (dete ction limits: 5 mug L-1 of water and 7 mug kg-1 of soil, for 75 s prec oncentration time). Relative errors were lower than 3.7% and relative standard deviations smaller than 4.5%.