Novel polypyrrole based all-solid-state potassium-selective microelectrodes

Abstract

Potassium-selective potentiometric microelectrodes with a polypyrrole solid internal contact were fabricated by the application of a potassium-selective bis-crown ether ligand based, plasticized poly(vinyl chloride) (PVC) membrane to the surface of conducting polymer modified Pt, Au or C micro disk electrodes. The selectivity and sensitivity of the new type of potentiometric potassium microelectrode were found to be comparable with those of the conventional macro ion-selective electrodes and of the micropipet type microelectrodes based on the same ionophore. The ease of preparation and robustness are the main advantages of this new electrode design, which can replace the classical micropipet type microelectrodes in many applications. The microelectrodes showed good dynamic characteristics and were used successfully in a wall-jet cell incorporated flow injection analysis system and as a measuring tip in scanning electrochemical microscopy. The polypyrrole modified substrate electrodes can be made selective for different ions just by changing the ionophore in the plasticized PVC membrane, which can extend their use to a wide range of applications.