Speciation of arsenic by potentiometric stripping analysis using gold(III) solution as chemical reoxidant and a wall-jet flow cell

摘要

A simple procedure is described for the potentiometric stripping of arsenic with a wall-jet cell by means of potentiostatic co-deposition of gold and arsenic at a glassy-carbon electrode and subsequent chemical stripping with Au(III). Optimum medium containing 160 mg L-1 of Au(III) in HCl 0.1 M, where it is possible to speciate As(III) and As(V). As(V) was electrodeposited directly without prior chemical reduction at working electrode. As(III) was first determined at an electrodeposition potential of -0.1 V Afterwards, total arsenic was determined by an electrodeposition potential of -0.7 V, from the area of peak obtained of the differential stripping potentiogram by using the standard addition method. The original As(V) concentration in the sample was calculated by difference. The possibilities of the optimized method were demonstrated by determinations of As(III), As(V) and total arsenic in samples of polluted water.