An ion-selective electrode in conjunction with a reference electrode. Generally, the cell contains two reference electrodes, internal and external, and the thin film or membrane recognition-transduction element. However, besides this conventional type of cell (with solution contact on both sides of the membrane) there are cell arrangements with wire contact to one side of the membrane (all solid state and coated wire types).
PAC, 1994, 66, 2527. 'Recommendations for nomenclature of ionselective electrodes (IUPAC Recommendations 1994)' on page 2531 (https://doi.org/10.1351/pac199466122527)