Selective permeation of hydrogen peroxide through polyelectrolyte multilayer films and its use for amperometric biosensors

A platinum electrode was coated with polyelectrolyte multilayer (PEM) films to prepare an amperometric hydrogen peroxide sensor which can be used in t he presence of possible interferences such as ascorbic acid, uric acid, and acetaminophen. The PEM films were prepared on the surface of a Pt disk ele ctrode by an alternate deposition of polycation and polyanion from the aque ous solutions through electrostatic force of attraction. The Pt electrodes coated with a poly(allylamine)/poly(vinyl sulfate) or poly(allylamine)/poly (styrenesulfonate) film were used successfully for detecting H2O2 selective ly in the presence of the possible interfering agents. It was suggested tha t H2O2 can diffuse into the PEM film smoothly while the ascorbic acid, uric acid, and acetaminophen cannot penetrate the film by a size exclusion mech anism. On the other hand, the electrodes coated with PEM films containing p oly(ethyleneimine) or poly(diallyl-dimethylammonium chloride) were not usef ul for the selective determination of H2O2. The results were rationalized b ased on the different permeability of the films due to the different molecu lar density or packing in the PEM films. The PEM film-coated electrode was useful for constructing glucose biosensors by coupling with glucose oxidase .