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 mV 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 × 10−8 M. Concentrations of 4 × 10−8 to 5 × 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.