Basic response principles of voltammetric ion-selective solvent polymeric membrane sensors

Potentiometric and optical sensors that make use of highly selective, lipophilic ionophores embedded in aplasticized polymeric environment are now well understood and established. This paper discusses how these membranes may be optimally used in a voltammetric or pulsed amperometric transduction mode. It is shown that the inner membrane phase boundary region should preferably be polarizable, unlike some of the classical voltammetry work on liquid-liquid interfaces. In addition, the materials properties of plasticized PVC membranes will reduce ion mobilities in the organic phase significantly, which will reduce stir effects of the sample and simplify the theoretical response models for these types of sensors. Results are shown on ionophore-free PVC membranes doped with a lipophilic salt.