Indirect determination of sulfide ions in water samples at trace level by anodic stripping voltammetry using mercury film electrode

Abstract

A simple and sensitive indirect determination method for sulfide in water samples by anodic stripping voltammetry (ASV) using mercury-film electrode (MFE) has been developed, which is based on the determination of residual cadmium ion after reaction of Cd²⁺ with S²⁻. The linear range is adjustable depending on Cd²⁺ concentration, for example, the determination of S²⁻ can be achieved in the range of 1.5–7.0 × 10⁻⁶ mol L⁻¹ by selecting 3.0 × 10⁻⁶ mol L⁻¹ Cd²⁺. The detection limit is 1.3 × 10⁻⁸ mol L⁻¹ under optimum conditions, and the relative standard deviation (RSD, n = 10) for 2.0 × 10⁻⁶ mol L⁻¹ S²⁻ is 0.7%. Compared with other methods, this method has the following prominent advantages: with low detection limit, easy to operate and less interference. The proposed method has been successfully applied to the determination of S²⁻ in synthetic wastewater, lake water, beverage, spring water and real wastewater samples.