Thorium selective electrode using zirconium phosphoborate as electroactive material

Abstract

Solid heterogeneous membrane selective for thorium ions containing zirconium phosphoborate as electroactive material is reported here as an ion selective electrode with a reproducible slope of 50.0 mv/decade. The electrode shows linear response in the concentration range 10^-4<i>M</i>-10^-1 <i>M </i> workable in the <i>p</i>H range 3-5. Selectivity coefficients <i>(K_ij) </i> for the rare earth, alkali and alkaline earth metal ions have been measured. The effect of concentration of the primary and interfering ions on the <i>K_ij </i> 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 concentration of primary as well as interfering cations.