Estimation of dimethyl sulphoxide and submicrogram quantities of ruthenium(III) by catalysis of the cerium(IV)-dimethyl sulphoxide reaction in aqueous sulphuric acid media

Abstract

Ruthenium(III) catalyses the title reaction in the concentration range of 10^-2 ppm and the reaction rate bears a first order dependence on the catalyst concentration under the experimental conditions, [dimethyl sulphoxide] >> [cerium(IV)] >>> [ruthenium(III)] in 1.0 mol dm^-3. sulphuric acid media. From the measurement of rate of the process which is first order with respect to cerium(IV) (-dln[Ce^IV]/dt = <i>k</i>_o= <i>k_cat</i>[Ru^III]_T), ruthenium(III) can be estimated in the concentration range of 10^{- 2} ppm using the principle of catalytic kinetic method of analysis. This reaction can be utilised for oxidimetric determination of dimethyl sulphoxide.