PbO2-based graphite–epoxy electrode for potentiometric determination of acids and bases in aqueous and aqueous–ethanolic media

Abstract

The construction and analytical evaluation of a PbO₂-based graphite–epoxy electrode sensitive to H₃O⁺, based on incorporation of lead(IV) oxide in a graphite– epoxy matrix, are described. The data obtained from a variety of acid–base titrations in aqueous and aqueous– ethanolic media were compared with those obtained by use of a glass electrode under the same conditions. The proposed electrode provides a linear response in the pH range from 1 to 11 with a slope of –58.7 ± 0.3 mV pH^–1 and –60.8 ± 0.2 mV pH^–1 in aqueous and ethanolic media, respectively. The response time was less than 15 s and the lifetime of the electrode was at least eight months (ca. 5000 determinations) and its performance is good in pH determination and end-point detection in potentiometric acid–base titrations in both aqueous and aqueous– ethanolic media.