ELECTROSYNTHESIZED BILAYER POLYMERIC MEMBRANE FOR EFFECTIVE ELIMINATION OF ELECTROACTIVE INTERFERENTS IN AMPEROMETRIC BIOSENSORS

A lactate amperometric biosensor based on lactate oxidase immobilized in a poly(o-phenylenediamine) film grown on a polypyrrole-modified platinum electrode is described, The biosensor, which is fabricated by an all-electrochemical procedure, displays a response time in the low second range and an interferent rejection efficiency never achieved before, Ascorbate, mate, and cysteine, which are the most common endogenous electroactive components, produce a nondetectable bias even at their maximum physiological concentrations in blood. Exogenous paracetamol, which at present is the most difficult to manage electroactive interferent, is also very efficiently excluded; at the maximum observable physiological level of 0.2 mM, a truly negligible lactate bias of only 3 mu M (i.e., 0.15% at 2 mM lactate) is produced.