In situ biochemical reduction of interference in an amperometric biosensor with a novel heterobilayer configuration of polypyrrole/glucose oxidase/horseradish peroxidase

A novel heterobilayer configuration for in situ biochemical reduction of interference in the amperometric glucose biosensor is described. The heterobilayer biosensor was constructed by electrochemical formation of a polypyrrole film in the presence of horseradish peroxidase (HRP) on top of an immobilized glucose oxidase (GO) film. In the heterobilayer configuration, electro-oxidizible compounds such as ascorbate, urate and acetaminophen, which severely interfere with the amperometric detection, were oxidized by the catalytic reaction of horseradish peroxidase before reaching the electrode surface. As a source of hydrogen peroxide required for the preoxidation of interferents, a portion of diffusing-away hydrogen peroxide produced by glucose oxidase, was utilized without any external supply. Preparation conditions for the heterobilayer biosensor were optimized in terms of sensitivity for glucose and the reduction of interference. The biosensor showed a good suppression of interference and a negligible deviation (less than 5%) in the amperometric detection, especially when the glucose concentration was higher than 50 mM.