Hydrogen peroxide amperometric biosensor based on a peroxidase-graphite-epoxy biocomposite

An amperometric biosensor sensitive to hydrogen peroxide has been built, using a HRP-graphite-epoxy biocomposite. The proximity of the redox centers of the enzyme and the conductive sites at the surface of the electrode permits a direct regeneration of the enzyme. The response characteristics of this biosensor have been improved by adding powdered platinum to the matrix of the biocomposite. When Pt is absent, the working potential is −300 mV vs. AgAgCl and the response is linear between 0.03 mM and 7 mM. When 3% wt platinum is added to the biocomposite, a stable response is produced at −50 mV vs. AgAgCl and the linearity range lies between 0.09 mM and 9 mM. The response time is approximately 2s for both the cases.