RESPONSE CHARACTERISTICS OF CONDUCTIVE POLYMER COMPOSITE SUBSTRATE ALL-SOLID-STATE POLY(VINYL CHLORIDE) MATRIX MEMBRANE ION-SELECTIVE ELECTRODES IN AERATED AND NITROGEN-SATURATED SOLUTIONS

The characterization of a perchlorate ion-selective electrode, with a poly(vinyl chloride) matrix membrane on a conductive silver-epoxy composite, showed that electrodes with this type of internal solid contact have virtually the same electrochemical properties as electrodes constructed with the same sensor system (methyltri-n-octylammonium perchlorate and 2-nitro-p-cymene as mediator solvent) or commercially available electrodes for perchlorate ion, both of which have internal liquid contacts. The constructed all-solid-state electrodes were studied under a variety of experimental conditions (sodium perchlorate solutions of different concentrations, pH and extent of aeration) in order to determine the actual limitations of electrodes based on conductive plastic composites. Owing to the internal solid contact, these electrodes give rise to small drifts in continuously de-aerated solutions. However, this disadvantage does not hinder direct potentiometric measurements.