Sensitive electrochemical detection of arsenic (III) using gold nanoparticle modified carbon nanotubes via anodic stripping voltammetry

Gold nanoparticles were deposited electrolessly on multiwalled carbon nanotubes (CNTs) via in situ reduction of HAuCl₄ by NaBH₄. The resulting gold covered nanotubes were immobilised onto the surface of a glassy carbon electrode via evaporation of a suspension in chloroform. Anodic stripping voltammetry was performed with the modified electrode in As(III) solutions. A limit of detection (LOD based on 3σ) of 0.1 μg L⁻¹ was obtained but more importantly a sensitivity of 1985 μA μM⁻¹ was obtained with square wave voltammetry (SWV) in an optimised system with a deposition time of 120 s. These values, particularly the high sensitivity compare favourably with previously reported methods in the area of electrochemical arsenic detection.