Kinetics determination of electrogenerated hydrogen peroxide (H2O2) using carbon fiber microelectrode in electroenzymatic degradation of phenolic compounds

The kinetics of electrogenerated hydrogen peroxide (H2O2), which can activate peroxidases in an electroenzymatic process, was examined by an amperometric technique using a carbon fiber microelectrode that was modified by polyaniline (PAn) film and platinum particles. The electrogeneration of H2O2 was found to be dependent on the PH and applied potential, and resulting in a variable current response of the carbon fiber microelectrode. The highest amount of H2O2 was electrogenerated when 2.3 V was applied between the Pt/Ti anode and a reticulated vitreous carbon (RVC) cathode at pH 6.0, with a current response of 0.0190 mu A min(-1). Phenol was completely degraded by the electroenzymatic reaction of the immobilized horseradish peroxidase (HRP), and the time required for the electrogeneration of H2O2 increased according to the initial concentration of phenol. The degradation stoichiometric ratio between the electrogenerated H2O2 and the aqueous phenol under HRP immobilized on RVC was found to be 1:1. (C) 2009 Elsevier B.V. All rights reserved.