Three approaches to the development of selective bilayer amperometric biosensors for glucose by in situ electropolymerization

Three different glucose oxidase biosensors for the enzymatic determination of glucose, based on bilayer polymer coatings consisting of polypyrrole (PP y) acid poly(o-phenylenediamine), were developed. The electrode substrates are Pt metal, carbon paste and an organic conducting salt (tetrathiafulvale ne-tetracyanoquinodimethane), which introduces appreciable variability in t he electrode construction process. The three sensors were compared with one another and with bare and PPy monolayer-coated sensors in terms of perform ance in the determination of glucose in a synthetic serum sample. These con figurations provide improved selectivity against the interferences of elect roactive species such as ascorbic acid and uric acid, frequently present in biological samples, and the differences between them can be taken advantag e of in application to different kinds of samples.