Electrocatalytic oxidation of NO at electrode modified with Nafion–CoII–1,10-phenanthroline film and its application to NO detection

Abstract

The preparation and electrochemical characterization of a platinum electrode modified with Nafion–Co(phen)₂ as well as its application are described. Nafion film was employed as a carrier of Co(phen)₂²⁺ and a barrier against anionic species. The Co(phen)₂²⁺ mediator was immobilized on a Nafion film by self-assembly. The resulting Nafion–Co(phen)₂ film electrode exhibited catalytic activity toward NO oxidation at a potential around 0.70 V (versus Ag/AgCl/KCl_(sat)). The electrode was selective against nitrite and ascorbate. In phosphate buffer solution (pH 7.4), the NO oxidation current measured by 1.5 order differential linear sweep voltammetry and the NO concentration showed a linear relationship in the range 1.4 × 10⁻⁷–5.0 × 10⁻⁶M.