New method of gold-film electrode preparation for anodic stripping voltammetric determination of arsenic (III and V) in seawater.

A new method of efficient rotating gold-film glassy-carbon electrode preparation prior to the determination of As(III) and As(V) in seawater by anodic stripping voltammetry (ASV) is described. Factors affecting sensitivity and precision including pH, deposition time and potential, rotation and scan rate, and the nature of working electrode were investigated. Electroinactive As(V) was reduced to As(III) by gaseous SO(2) prior to ASV determination. For a deposition time of 4 min the determination limit was approximately 0.19 ppb. Precision of the proposed method was very good (RSD=2-0.6% at 1-5 ppb) and a relatively good accuracy determined by analysis of certified reference seawater (CASS-1) and seawater samples spiked with an arsenic standard solution, was also obtained.