Automated Determination of Cd 2+ and Pb 2+ in Natural Waters with Sequential Injection Analysis Device Using Differential Pulse Anodic Stripping Voltammetry

An electrochemical flow device has been developed for the determination of heavy metal ions (HMI) in water using multi-walled carbon nanotubes (MWCNTs)/Nafion(NA)/Hg electrode, by mean of differential pulse anodic stripping voltammetry coupled with sequential injection analysis. The accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of Hg. NA was used for MWCNTs immobilization for the long-term application of the electrode. The mercury film was cleaned after determination and another one would form during deposition. A lower limit of detection and a wider determination range of Cd 2+ and Pb 2+ could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified electrode. The real-time monitoring of Cd 2+ and Pb 2+ in fresh water using this device continued for 10 days. The results indicated that the method was potential for on-site and real-time determination of HMI in water samples.