Rapidly renewable and reproducible mercury film coated carbon paste electrode for anodic stripping voltammetry

Various mercury(I)/(II) salts of low solubility in aqueous solutions were investigated as modifiers for carbon paste electrodes. Such electrodes can be used to rapidly generate reproducible mercury-coated surfaces which are suitable for applications to anodic stripping voltammetric determinations of metal ions. This type of bulk-modified electrodes does not need a solution containing mercury ions to plate metallic mercury on the electrode surface. The mercury salts distributed throughout the bulk of the electrode acts as a source of mercury. In this work, we examined the plating and stripping characteristics of the chosen mercury salts and identified mercuric oxalate as the most suitable candidate for further studies. The mercuric oxalate modified carbon paste electrode was applied to the simultaneous anodic stripping voltammetric determination of Zn, Cd, Pb and Cu. The developed method, after optimization and testing, was utilized to determine Zn, Cd and Pb in a seawater sample.