Dual-signal anodic stripping voltammetric determination of trace arsenic(III) at a glassy carbon electrode modified with internal-electrolysis deposited gold nanoparticles

Abstract

A glassy carbon electrode (GCE) modified with internal-electrolysis deposited gold nanoparticles (AuNPsied) was applied to sensitively and selectively detect As(III) by anodic stripping linear sweep voltammetry (ASLSV). The AuNPsied/GCE was prepared based on the redox replacement reaction between a supporting-electrolyte-free aqueous HAuCl4 and a copper sheet in saturated KCl separated by a salt bridge. Under optimum conditions (0.5M aqueous H2SO4, 300-s preconcentration at −0.4V), the ASLSV peak current for the As(0)–As(III) oxidation responded linearly to As(III) concentration from 0.02 to 3μM with a limit of detection (LOD) of 0.9nM (0.07μgL−1) (S/N=3), while that for the As(III)–As(V) oxidation was linear with As(III) concentration from 0.02 to 1μM with a LOD of 4nM (0.3μgL−1) (S/N=3). An appropriate high-scan-rate for ASLSV can enhance both the sensitivity and signal-to-noise ratio. This method was applied for analyses of As(III) in real water samples.