Determination of mercury by open circuit adsorption stripping voltammetry on a platinum disk electrode

The open circuit accumulation of mercury by adsorption onto a platinum electrode, followed by constant potential reduction and an anodic voltammetric scan in a separate cell, has been used to develop a new analytical method for the determination of mercury. The re-oxidation stripping response of mercury was used as the analytical signal. An 8 min open circuit accumulation step in 10(-2) M nitric acid, a 20 s delay time at -0.2 V and a linear voltammetric scan between -0.2 and 1.5 V with a 500 mV s(-1) sweep rate in 0.05 M perchloric acid gives rise to a limit of detection of 1.2 x 10(-8) M. Concentrations of 4 x 10(-8) to 5 X 10(-7) M can be determined. The method has been applied to the determination of mercury in natural waters. No interferences from other metallic species were observed.