CONDUCTING-POLYMER-BASED ELECTROCHEMICAL SENSORS - THEORETICAL-ANALYSIS OF THE TRANSIENT CURRENT RESPONSE

A theoretical analysis describing the transient current response of a conducting-polymer-based amperometric chemical sensor to a concentrati on step is presented. The processes of substrate transport and substra te reaction within the polymer matrix are examined by solution of the time-dependent diffusion-reaction equation. Analytical expressions for the concentration profiles in the layer and the amperometric sensor r esponse are presented. The shape of the response is shown to be in goo d agreement with that obtained experimentally for the amperometric det ection of ascorbate at polypyrrole electrodes.