Simultaneous analysis of heavy metals in the water with microelectrodes

Abstract

Heavy metal ions such as zinc, cadmium, lead and copper in water were analyzed with microelectrode. Platinum microelectrodes were made by the chemical vapor deposition (CVD) process, and mercury was electroplated on platinum to yield a mercury microelectrode. Metal ion analysis was performed with these mercury coated microelectrodes. Employing the square wave anodic stripping voltammetry (SWASV) technique with the microelectrode, Cu, Zn, Cd, and Pb could be detected simultaneously. Their peak currents were directly proportional to ion concentration and detection limit was several ppb. The same experiment was carried out in the condition without supporting electrolyte. Cd and Pb were still analyzable and there was no loss in sensitivity. In all experiments, there was no need to stir sample solutions. The analytic performance enhanced by reducing the size of working electrode. The sensitivity increased to the detection limit of 1 ppb and fast response was achieved to shorten the analysis time.