Components of All-Solid-State Ion-Selective Electrodes (AS-ISEs)

Abstract

Ion-selective electrodes (ISEs) are a subclass of electrochemical sensor that are widely applied in several fields of clinical and environmental use, physiological sensing, and process control. ISEs are classified into three types, depending on the nature of the membrane material: glass, polymer or liquid, and crystal or solid. All-solid-state ion-selective electrodes (AS-ISEs) have a solid-based selective membrane; AS-ISEs convert the activity of a specific ion to a measurable electrical signal that can be measured without the internal filling solution required by conventional ISEs. The main components of AS-ISEs are a conductive electrode, a transducer or solid contact, and an ion-selective membrane (ISM). The ISM is involved in the recognition and selection of the targeted ion; it consists of a polymeric matrix, an ionophore, a plasticizer, and ionic additives. The analytical performance of AS-ISEs is influenced by the choice of and amount of materials in the main components. This chapter will introduce the main components and the materials used for the fabrication of AS-ISEs.