Ultrasensitive adsorptive-catalytic stripping voltammetry of iron in the presence of hydroxamic acids and hydrogen peroxide

Abstract

An ultratrace catalytic–adsorptive stripping voltammetric procedure for the determination of trace amounts of iron is reported. The method is based on the interfacial accumulation of the iron-N-benzoyl-N-phenylhydroxylamine complex on the hanging mercury drop electrode, followed by catalytic reduction of the adsorbed complex in the presence of hydrogen peroxide. The presence of hydrogen peroxide greatly amplifies the adsorptive stripping response. Optimum experimental conditions have been explored to give an extremely low detection limit of 1.8 × 10−10M (10 ng/L) iron following 10min accumulation. Analogous improvements are reported for other hydroxamic acid complexes of iron. Such acids hold great promise for developing additional adsorptive stripping procedures.