Amperometric biosensors based on enzyme electrodes satisfy many of the requirements for clinical assays, environmental monitoring or process control. Unfortunately, the inherent specrficity of the biocatalytic (recognition) reaction is compromised by the partial selectivity of the electrode transducer. Coexrstmg electroactive compounds, present in complex samples, such as, whole blood or fermentation broths, may result in overlapping current signals. For example, the clinical monitoring of glucose or lactate is commonly compromised by anodic contributions from easily oxidizable constituents of biologic fluids, such as, uric or ascorbic acids. The degree of such interference is strongly influenced by the operating potential.