Potentiometric Measurements of Ion Activities with Neutral Carrier-Based Electrodes

Ion-selective electrodes permit the potentiometric measurement of the activity of a given ion in the presence of other ions. Two general arrangements of potentiometric liquid membrane electrode cells are shown in Fig. 5.1. The ion-selective electrode consists of a galvanic half-cell containing the liquid membrane, the internal filling solution and the internal reference electrode. The other half-cell is represented by an external reference electrode in contact with a reference electrolyte. Such a cell assembly is described in (Eq. 5.1)