Novel Ion-to-Electron Transduction Principle for Solid-Contact ISEs

Solid-contact ion-selective electrodes (SC-ISEs) are traditionally employed as potentiometric sensors, where the ion activity is related to the zero-current potential of the sensor versus the reference electrode. In this communication, an alternative ion-to-electron transduction principle for SC-ISEs is introduced. The suggested signal transduction principle resembles constant-potential coulometry utilizing the redox capacitance of the internal solid contact in order to convert changes in ion concentration (activity) into electrical current and charge. This short communication provides proof-of-concept for the suggested signal transduction method for SC-ISEs utilizing poly(3,4-ethylenedioxythiphene) (PEDOT) as the solid contact that was coated with a cation-sensitive polymeric membrane.