Eliminating the interference of ascorbic acid and uric acid to the amperometric glucose biosensor by cation exchangers membrane and size exclusion membrane

The characteristics of a multiuse planar amperometric biosensor modified with Nafion and/or polyion membrane were investigated. A new enzyme immobilization process was proposed, in which the polyvinyl alcohol bearing a styrylpyridinium (SbQ)/glucose oxidase composite was treated with glutaraldehyde vapor prior to the photo-crosslinking reaction. The resulting planar enzyme electrode remains active for at least 150 days. Compared with poly-L-lysine/poly (4-stryenesulfonate) polyion complex membrane the Nafion membrane showed marked effect to reduce the electrochemical response of the modified planar enzyme electrode to the biological interferents, such as ascorbic acid and uric acid. Furthermore, Nafion membrane can effective restricting the oxidized anionic interferent to adhear on its surface, thereby the fouling of the electrode was avoided.