Polypyrrole-modified electrodes with induced recognition sites for potentiometric and voltammetric detection of copper(II) ion

Polypyrrole modified electrodes prepared by electropolymerization of pyrrole in the presence of an anionic complexing ligand, Eriochrome Blue-black B, were templated with respect to copper ions and used for potentiometric and voltammetric detection of this ion. The templating process improved the analytical response characteristics of the electrodes, particularly their selectivity, with respect to copper ion. The improvement depends on both the incorporated ligand and the templating process, with the latter being more important. The potentiometric response of the electrode was linear within the Cu2+ concentration range 5 × 10−8 to 1 × 10−2 M with a near-Nernstian slope of 28.4 mV and a detection limit of 1 × 10−8 M. The templated electrode showed good potentiometric selectivity for copper ion with respect to several metal ions, including mercury and silver ions. The electrodes were also used for preconcentration differential pulse anodic stripping voltammetric measurement of copper ion. Experimental results exhibited that the stripping peak currents for the incorporated copper species were dependent on the metal ion concentration in the range 3.2 × 10−9 to 1 × 10−4 M. Several transition metal ions did not show significant interference in the voltammetric determination of copper ion, however, mercury and silver ions caused significant interferences.