Biosensors based on conducting filled polymer all-solid-state pvc matrix membrane electrodes

Abstract

Transducers consisting of PVC matrix membranes applied to conducting filled polymers and featuring no inner reference solution are proposed as viable alternatives to the construction of potentiometric biosensors. The construction procedure basically involves the application of biocatalyst layers (e.g. immobilized enzymes or whole bacterium cells) on mobilecarrier PVC membranes formed in-situ and deposited directly on a conductive plastic support which functions as an internal solid contact. The chief advantage of this construction procedure is the ease with which sensors in different shapes and sizes can be prepared. Thus this technique allows the obtainment of flow-through sensors for use in flow-injection analysis, of which those with sandwich configuration are particularly suitable for the construction of flow-through electrochemical biosensors. The results obtained with various potentiometric urea sensors in different configurations and based on all-solid-state ammonium-selective electrodes constructed by the proposed technique are reported.