Arsenic (III) detection with underpotential deposition on gold

We report a new, sensitive stripping voltammetric method for the detection of As(III) in aqueous solution using either a gold macroelectrode or a gold nanoparticle-modified glassy carbon electrode (GCE) based on the underpotential deposition (UPD) of As ad-atoms. The pre-concentration step deposits and accumulates As ad-atoms onto gold and is followed by a potential sweep to strip the ad-atoms with no interference from Cu(II) or Cl^- at either electrode. Linear responses were found for the range 0.01 μM to 0.1 μM or 0.005 μM to 0.1 μM at gold macroelectrodes and gold nanoparticle-modified electrodes, respectively. The visually clearly discernable signals recorded at 0.005 μM (0.4 ppb) on gold nanoparticle-modified electrodes suggests that this method has practical value given the WHO limit of 0.13 μM (10 ppb) for drinking water.