Static and flow injection voltammetric determinations of total phosphate and soluble silicate in commercial washing powders at a glassy carbon electrode

Abstract

Anionic detergents have been shown to lower markedly the differential-pulse voltammetric peak currents obtained for 12-molybdophosphate and 12-molybdosilicate in aqueous solutions, but when ethanol - water or acetone - water (1 + 1 V/V) solutions are used there is no interference. Static differential-pulse voltammetric and flow-injection voltammetric procedures have been developed for the determination of total phosphate (involving hydrolysis of polyphosphates) and soluble silicate in commercial washing powders using these partly aqueous conditions. The effect of increasing ethanol and acetone concentrations on the differential-pulse voltammograms has been studied.