Anodic stripping voltammetric characteristics of carbon composite electrodes with mercuric precursors

Surface modification of a polymeric carbon composite electrode with various mercuric precursors for the anodic stripping voltammetric analysis of heavy metals has been studied. Several microliters of the solution or suspensions of mercuric compounds such as HgCl2. HgO or Hg2Cl2 in cyclohexanone containing a polymeric binder were dispensed onto the surface of the electrode. then dried at room temperature. By simple in situ treatment. the precursors were reduced to mercury droplets. which serve as metal collectors. The mercuric oxide appeared to be the best mercuric precursor in terms of the anodic stripping voltammetric characteristics as well as stability. The network structure of the polymeric binder film stabilized the microdroplets of the mercury resulting highly reproducible stripping voltammetric signals. Any particular difference was not noticeable between polymeric binders. The contents of the mercuric oxide and polymeric binder were optimized. The anodic stripping voltammetric characteristics of the mercuric oxide modified electrode were very similar to those of the mercury film electrode, but the reproducibility. stability, and simplicity of electrode preparation were improved.