Recent Advances in Analytical Potentiometry with Ion-Selective Electrodes

Historical developments in analytical potentiometry are briefly introduced and compared with those in polarography and coulometry: in the discussion special emphasis is given to the selectivities of these methods. Next, recent advances are described in ion-selective electrodes of both the solid membrane and the liquid membrane types; an extremely small ion-selective reference electrode assembly made with a field effect transistor is described and the use of solid solvent as membrane material is discussed. The enhancement of the selectivity of anion electrodes by p-tert-octylphenol is introduced and the effect of the enhancement is explained after a discussion from a voltammetric standpoint of the mechanisms of potential generation at the electrode-solution interface. As an example of the applications of the ion-selective electrode, the use of the cation-sensitive glass electrode for the measurement of the activities of metal ions in non-aqueous solvents is introduced.