Electrochemical Preparation of a Copper Ion Selective Electrode based on Polypyrrole Conducting Polymer Doped with Ponceau 4R Azo Dye

A solid state copper electrode is reported based on polypyrrole conducting polymer film doped with Ponceau 4R azo dye. The sensing film was prepared in aqueous solution via electropolymerization of pyrrole (10.0 mM) and Ponceau 4R azo dye (2.0 mM) as ionophore, potentiostatically (Eapp.=0.80 V vs. SCE) using pencil graphite as working electrode. The structural characteristics of the prepared copper electrode were studied by scanning electron microscopy, Fourier transform infrared and energy dispersive spectroscopy. The fabricated electrode showed a linear Nernstian response over the range of 1.0×10-5 to 5.0×10-2 M with slope of 29.28±0.20 mV per decade over the pH range of 4-6. The sensor shows a fast response time ( < 15 s), good shelf lifetime and reasonably high selectivity with respect to many cations including alkali, alkaline earth, and transition metal ions. A detection limit of 6.70 ?M was obtained.