Voltammetric Determination of Dialifos in Soils with a Mercury Film Ultramicroelectrode.

An extraction-adsorptive stripping voltammetric procedure for the determination of the pesticide dialifos in soil samples using microwave-assisted solvent extraction and a mercury film ultramicroelectrode was developed. The method is based on the use of hexane-acetone solvent (1:1, v/v) and on controlled adsorptive accumulation of the insecticide at the potential of -0.10V (versus Ag/AgCl) in the presence of Britton-Robinson buffer (pH 2.0). Soil sample extracts were analyzed directly after drying and redissolution with the supporting electrolyte, but without other pretreatment. The limit of detection obtained for a 10 sec collection time was 2.0 µ 10 ^-8 mol L^-1. Recovery experiments for the global procedure, at the 0.100 µg g^-1 level, gave satisfactory average and standard deviation results for the two different soils tested. [ABSTRACT FROM AUTHOR]