The voltammetric determination of peroxynitrite at a mercury film electrode

This report describes the direct voltammetric detection of peroxynitrite (PN, ONOO-), an important analyte in many physiol. biochem. pathways, at a mercury film electrode (MFE) at alk. pH. The voltammetric response of PN is obsd. as a cathodic inverted peak when the potential is swept in the oxidative direction at ~-0.1 V vs. a Ag/AgCl/1 M KCl ref. electrode. An mechanism is proposed to explain this behavior involving the initial formation of a thin film of Hg(I) oxide on the electrode which is then oxidized by PN to form HgO in a chem. step. The HgO is then reduced back to Hg(0) at the electrode potential of interest resulting in a net cathodic current. The parameters affecting the voltammetry of PN at a MFE, including the concn. of PN (10-5-10-4 M), the effect of varying scan rate (5-100 mV s-1) and pH are investigated and the kinetics of PN decay in alk. solns. ranging from pH 9-13 are explored electrochem. [on SciFinder(R)]