Abstract: A new electrochemical biosensor and method of its use. The electrochemical biosensor has a pair of electrodes consisting of a working electrode and a counter electrode made of the same electrically conducting materials. The counter electrode may be the same size or smaller than the working electrode. The biosensor includes a sample receiving portion wherein a portion of the electrode surfaces is covered by a reagent that includes a redox mediator and an enzyme. A fluid that contains an analyte is added to the sample receiving portion. A reaction involving the analyte, enzyme and redox mediator occurs. After this reaction is complete, an electrical potential difference is applied between the electrodes. Diffusion limited current is measured and correlated to the concentration of analyte in the fluid.

Abstract: A biosensor that includes working and counter electrodes of substantially the same size and made of the same electrically conducting material. A reagent is contained in a reagent well in the biosensor. The reagent includes a redox mediator, an enzyme, and a buffer, and covers substantially equal surface areas of portions of the working and counter electrodes. When a sample, containing the analyte to be measured, is added to the reagent well, a reaction occurs that oxidizes the analyte and reduces the redox mediator. After this reaction is complete, an electrical potential difference is applied between the electrodes. The amount of oxidized form of the redox mediator at the counter electrode and the applied potential difference must be sufficient to cause diffusion limited electrooxidation of the reduced form of the redox mediator at the surface of the working electrode.