A Polarographic and Voltammetric Study of the Copper-Phenazopyridine Monohydrochloride System in Phosphate Buffer Medium

Abstract

The electrochemical behavior of copper complexed with phenazopyridine monohydrochloride (2,6-diamino 3-phenylazo-pyridine monohydrochloride, pyridium) has been studied in 0.1 M phosphate buffer (pH 6.0). It was observed that CuII ions in the presence of pyridium are reduced at the mercury electrode in two distinct stages; this is a consequence of the interaction of pyridium with CuI ions. Tests showed that pyridium forms stable complexes with CuI and CuII ions. However, it was found that pyridium formed a 1:1 complex with CuI and a 1:2 complex with CuII ions.