A novel catalytic adsorptive stripping voltammetric method of iron determination as its 1,2-cyclohexanedone dioxime complex

The sensitive catalytic adsorptive stripping voltammetric method for the determination of trace iron in the supporting electrolyte consisting of 0.1 M ammonia buffer, 0.05-0.15 mM 1,2-cycloheksanedione dioxime and 0.14 M NaNO2 is presented. The method is based on adsorptive accumulation of an iron-nioxime complex on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of the catalytic reduction current of the adsorbed complex in the presence of sodium nitrite. The detection limit obtained for a 20 s accumulation time was 0.90 nM iron, the RDS was 3%, and the linearity range amounted from 3.6 to 107.4 nM of iron. Possible interferences from the coexisting ions and surface-active substances were investigated.