Hydrogen peroxide sensitive amperometric biosensor based on horseradish peroxidase entrapped in a polypyrrole electrode

The enzyme horseradish peroxidase (HRP) has been entrapped in situ by electropolymerization of pyrrole onto a platinum electrode. The latter was previously coated by a polypyrrole layer for better adhesion of the biocatalyst film and in order to avoid the enzyme folding onto the Pt electrode. The biosensor allowed the determination of hydrogen peroxide in the concentration range comprised between 4.9 x 10(-7) and 6.3 x 10(-4) M. The biosensor retained more than 90% of its original activity after 35 days of use.