THORIUM SELECTIVE ELECTRODE USING ZIRCONIUM PHOSPHOBORATE AS ELECTROACTIVE MATERIAL

Solid heterogeneous membrane selective for thorium ions containing zir conium phosphoborate as electroactive material is reported here as an ion selective electrode with a reproducible slope of 50.0 mv/decade. T he electrode shows linear response in the concentration range 10(-4)M- 10(-1)M workable in the pH range 3-5. Selectivity coefficients (K-ij) for the rare earth, alkali and alkaline earth metal ions have been mea sured. The effect of concentration of the primary and interfering ions on the K-ij values and slope of the electrode has also been studied. The electrode shows fairly good selectivity for thorium ions over the rare earth cations. The selectivity decreases with increase in the con centration of primary as well as interfering cations.