Voltammetric Sensing of Mercury and Copper Cations at Poly(EDTA-like) Film Modified Electrode

Complexing polymer-coated electrodes have been synthesized by oxidative electropolymerization of ethylenediamine tetra-N-(3-pyrrole-1-yl)propylacetamide (monomer L). The presence of four polymerizable pyrrole fragments on the same EDTA skeleton was thought to confer enhanced rigidity and controlled dimensionality to the resulting complexing materials, which were used for the electrochemical detection of Hg(II), Cu(II), Pb(II) and Cd(II) ions by means of the chemical preconcentration-anodic stripping technique. The polyamide electrode material showed particularly a significant selectivity towards mercury ions, even in the presence of a large excess of other metal cations. Moreover, the use of imprinted polymer-coated electrodes prepared by electropolymerization of L in the presence of metal cations turned out to significantly improve the detection limits, down to 5 x 10(-10) mol L-1 for Hg(II) and Cu(II) species.