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

• Internal-electrolysis deposition of gold nanoparticles on glassy carbon electrode.
• Deposition of gold nanoparticles in supporting electrolyte-free solution.
• Sensitive and selective anodic stripping voltammetric analysis of As(III).
• Signaling of both As(0)–As(III) and As(III)–As(V) oxidation.

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 (0.5 M aqueous H2SO4, 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.