Amperometric biosensor involving covalent immobilization of choline oxidase and butyrylcholinesterase on a methacrylate-vinylene carbonate co-polymer.

A two-enzyme sensor for the determination of choline esters was prepared by the covalent co-immobilization of choline oxidase and butyrylcholinesterase on polymer membranes, obtained by radiation-induced co-polymerization of 2-hydroxyethylmethacrylate and vinylene carbonate at low temperature. The enzyme-modified membrane was applied to a platinum electrode and the determination of substrates was based on the electrochemical detection of enzymically generated H2O2. The analytical characteristics of this sensor, including the optimization of immobilization procedures, calibration curves for different substrates, pH and temperature effects and stability, are described.