Potentiometric determination of proton activities in solutions containing hydrofluoric acid using thermally oxidized iridium electrodes

Abstract

A robust sensor based on iridium oxide is shown to be suitable for use in determining proton activities in solutions containing hydrofluoric acid. Fabricated by a thermal growth process, the low-impedance sensor possesses analytical utility for regulating acidity levels in etching media and pickling-baths. The thermally oxidized electrodes function satisfactorily in hydrofluoric acid solutions with concentrations up to 28 mol dm–3 and show responses comparable to electrodes prepared by the more involved method of reactive sputtering.