Cyclic voltammetry study of iohexol behavior in its commercial formulation omnipaque on Ti/Pt electrode

Résumé

The electro-oxidation of omnipaque was investigated using cyclic voltammetry techniques on platinum electrode prepared by thermal decomposition. The influence of omnipaque concentration, scan rate, temperature and pH were studied. Kinetic parameters such as anodic transfer coefficient, activation energy and Tafel slope were estimated. The scanning electron micrograph of the platinum electrode indicates a smooth and cracked structure. This study revealed that the platinum electrode can be used for a quantitative determination and electrocatalytic degradation of omnipaque. The electro-oxidation of omnipaque on the platinum electrode is an irreversible and diffusion-controlled process followed by a homogeneous chemical reaction. It takes place via direct electron transfer at the platinum/electrolyte interface and indirect oxidation facilitated by hydroxyl radicals generated in situ. In the pH range studied, the electro-oxidation of omnipaque involves an exchange of 1 proton and 5 electrons.

The activation energy, anodic transfer coefficient and Tafel slope were 18.456 kJ/mol, 0.34 and 96.4 mV, respectively.