Use of ruthenium–(ethylenedinitrito)-tetraacetic acid monohydrate ion immobilized on zirconium(IV) oxide coated silica gel surface as an amperometric sensor for oxygen in water

Abstract

[Ru(edta)H₂O]^– adsorbed on zirconium(IV) oxide coated on the surface of silica gel was used for the construction of an amperometric sensor for O₂ in water, using a carbon paste electrode. The adsorbed complex electrocatalyses the oxygen reduction reaction at –250 mV versus SCE. The cathodic current was linear for an oxygen concentration between 0.55 and 8.0 ppm, with a correlation coefficient of 0.998 and a relative standard deviation of 2.7%. The sensor response is constant within the solution pH values 2.0 and 6.5. The concentration of O₂ in a natural sample was also determined.