ELECTROPOLYMERIZED 1,2-DIAMINOBENZENE AS A MEANS TO PREVENT INTERFERENCES AND FOULING AND TO STABILIZE IMMOBILIZED ENZYME IN ELECTROCHEMICAL BIOSENSORS

A platinized, reticulated vitreous carbon (RVC) electrode, immobilized with glucose oxidase and electropolymerized with 1, 2-dlamlnobenzene, Is used In the construction of a sensor for the determination of glucose In human serum. A flow injection analysis (FIA) system was used for the determinations. The platinum coating provides an increased current response from the oxidation of hydrogen peroxide, as compared with a bare RVC electrode. The 1, 2-diaminobenzene polymer coating drastically reduces the effects of electrochemlcally active interferents, such as L-ascorblc acid, uric acid, and L-cysteine, and virtually eliminates electrode fouling by proteins in blood serum. There Is no fouling of the sensor after 60 repetitive injections of serum. The polymer film also Increases the thermal stability of the Immobilized glucose oxidase. The enzyme remains active over one and one-half months of dally use, and the 1, 2-diamlnobenzene polymer film can be redeposited, as needed, during the working lifetime of the electrode. Thermal studies were done on Immobilized enzyme electrodes using carbodilmide as a covalent linking agent or glutaraldehyde as a cross-linking agent. Results obtained with this biosensor showed excellent correlation with National Institute for Standards and Technology serum samples. © 1990, American Chemical Society. All rights reserved.