NEW METHOD OF GOLD-FILM ELECTRODE PREPARATION FOR ANODIC-STRIPPING VOLTAMMETRIC DETERMINATION OF ARSENIC(III) AND ARSENIC(V) IN SEAWATER

A new method of efficient rotating gold-film glassy-carbon electrode p reparation 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 inv estigated. Electroinactive As(V) was reduced to As(III) by gaseous SO, prior to ASV determination. For a deposition lime of 4 min the determ ination limit was approximately 0.19 ppb. Precision of the proposed me thod was very good (RSD = 2-0.6% at 1-5 ppb) and a relatively good acc uracy determined by analysis of certified reference seawater (CASS-I) and seawater samples spiked with an arsenic standard solution, was als o obtained. (C) 1997 Elsevier Science B.V.