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

摘要

A glassy carbon electrode (GCE) modified with internal-electrolysis deposited gold nanoparticles (AuNPs_(ied)) was applied to sensitively and selectively detect As(III) by anodic stripping linear sweep voltammetry (ASLSV). The AuNPs_(ied)/GCE was prepared based on the redox replacement reaction between a supporting-electrolyte-free aqueous HAuCl_4 and a copper sheet in saturated KCl separated by a salt bridge. Under optimum conditions (0.5 M aqueous H_2SO_4, 300-s preconcentration at -0.4 V), the ASLSV peak current for the As(0)-As(III) oxidation responded linearly to As(III) concentration from 0.02 to 3 μM with a limit of detection (LOD) of 0.9 nM (0.07 μg L~(-1)) (S/N = 3), while that for the As(III)-As(V) oxidation was linear with As(III) concentration from 0.02 to 1 μM with a LOD of 4 nM (0.3 μg L~(-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.