Selective determination of rubidium ions by a solid membrane electrode

An araldite-based titanium tungstoarsenate solid membrane electrode has been developed to estimate rubidium ion concentration in the range 10^?1 to 4×10^?5M. The electrode shows considerable selectivity for rubidium ions over other cations. Treatment with a 10^?4M solution of the anionic surfactant, sodium dodecyl sulphate, not only makes the membrane immune to detergent effects but the selectivity and validity range of the electrode assembly are also improved.