Determination of Inorganic Arsenic As(III) in Water by Linear Sweep Anodic Stripping Voltammetry Using Gold Ultra-Microelectrode Array

A gold ultra-microelectrode array has been developed for the determination of arsenic As(III) ions by linear sweep anodic stripping voltammetry (LSASV). The deposition potential (Edep) and time (tdep) and supporting electrolytes were investigated. The repeatability, linearity, accuracy of the proposed method and the effect of pH and interference ions were evaluated. It was found that As(III) can be determined by the proposed method using our developed gold ultra-microwire electrode at any pH including the pH values typical for natural waters. Well defined voltammetric waves at Edep = -0.450 V (vs. Ag/AgCl/3M KCl reference electrode), tdep = 100 s and 1.000 V.s scan rate are obtained in 1M H3PO4 supporting electrolyte. A good linear relationship between LSASV peak current and As(III) concentration is observed for the typical values in natural waters and in arsenic contaminated ones. The limit of detection was 2 ng.L (signal-to-noise ratio = 3). The obtained results suggested that the fabricated gold chip would facilitate monitoring of As(III) in natural waters by linear sweep anodic stripping voltammetry.