Polarographic Evidence for the Reduction of Nitrite to Nitrogen Monoxide by Iron(II) Ions in Neutral Buffer Solutions and Characteristics of Cathodic Waves of Nitrogen Monoxide in the Presence of Iron Ions and Citrate

Abstract

The reduction of NO₂^- to NO by Fe²⁺ in neutral buffer solutions containing excess citrate has been substantiated polarographically. Nitrogen monoxide exhibited three cathodic waves having a characteristic maximum in the presence of iron ions and citrate. The two waves ( E_1/2s=-0.56 and -0.75 V vs SCE at pH 7) were of kinetic current, whereas the third wave(E=_1/2=10V) having a maximum was a diffusion-controlled one. The NO concentration dependence of the limiting currents of the three waves showed a relation with the form of Langmuir's adsorption isotherm.