AMPEROMETRIC SUBSTRATE DETERMINATION IN FLOW-INJECTION SYSTEMS WITH POLYPYRROLE ENZYME ELECTRODES

Polypyrrole/glucose oxidase electrodes with the enzyme covalently bound to the outer surface of the functionalized polymeric network are used together with a similarly prepared non-enzyme electrode to determine glucose in the presence of cooxidizable compounds in fruit juices and wines. Due to the size-exclusion properties of polypyrrole, the thicknesses of the conducting polymer layers at both electrodes have to be equal to allow interfering compounds to be discriminated. A significant improvement with respect to the reliability of glucose measurements in real samples and the number of analyses with time is possible with these systems, as is proved by comparison with standard spectrophotometric procedures.