Modification of Gold Nanoparticles at Carbon Electrodes and the Applications for Arsenic (III) Detections

Modification of carbon, including boron-doped diamond (BDD) and glassy carbon (GC), using gold nanoparticle (AuNP) was developed by self-assembly technique. This technique is based on electrostatic interaction between citratecapped AuNP to amine terminal groups after surface modification of BDD and GC. The fabricated materials, AuNP-BDD and AuNP-GC, were then utilized as electrodes for As^3+ detection using anodic stripping voltammetry (ASV) technique. Anodic stripping voltammograms of both AuNP-BDD and AuNP-GC electrodes showed similar peak potentials of As° oxidation at ~0.21 V (vs. Ag/AgCl) in optimum conditions of -500 mV, 180 s, and 100 mV/s for deposition potential, deposition time, and scan rate, respectively. AuNP-BDD shows better performances in the case of wide linear concentration range (0-20 mM) and low limit of detection (0.39 μM or 4.64 ppb), whereas those of AuNPGC were linear in the concentration range of 0-10mM with a detection limit of 0.14 μM (13.12 ppb). Excellent reproducibility was shown with RSDs (n=20) of 2.93% and 4.54% at AuNP-BDD and AuNP-GC, respectively. However, decreasing of current responses in 6-concecutive days was found more at AuNP-BDD (~20.1%) than that at AuNP-GC (~2.8%).