Electrochemical approach to detect the presence of peroxynitrite in aerobic neutral solution

This work describes the conditions of use of bare gold electrode to detect electrochemically the presence of peroxynitrite ONOO− in phosphate buffer solution at pH 7.1. As ONOO− is extremely unstable in neutral solution, current–potential curve was reconstructed between −0.5 and 0.7 V vs SCE by amperometry experiments at rotating disk electrode at different potentials. Comparison of this reconstructed curve with voltammograms of the common interfering species (dopamine, hydrogen peroxide, nitrite, ascorbic acid and glutamate) shows that the presence of ONOO− can be selectively determined at −0.1 V vs SCE. This detection occurs through the electrochemical reduction of peroxynitrous acid ONOOH, the conjugated acid of ONOO−. Detection of ONOO− produced in situ by the reaction of nitric oxide with superoxide was also achieved.