Hydrogen peroxide sensor based on horseradish peroxidase immobilized nanostructured cerium oxide film

Abstract

Nanostructured cerium oxide (NanoCeO2) film deposited onto indium-tin-oxide (ITO) glass substrate by solution casting has been used for immobilization of horseradish peroxidase (HRP) via physiosorption technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis and electrochemical techniques have been utilized for characterization of NanoCeO2/ITO electrode and HRP/NanoCeO2/ITO bioelectrode. The HRP/NanoCeO2/ITO electrode exhibits value of the apparent Michaelis-Menten constant (Km) as 2.21 μM, linear regression coefficient as 0.998 and linearity for hydrogen peroxide as 1.0-170 μM obtained using electrochemical response measurements. Besides this, HRP/NanoCeO2/ITO bioelectrode can be used about 20 times and is stable for 5 weeks at 4 °C. The results of photo-response studies carried out on HRP/NanoCeO2/ITO bioelectrode indicate reasonable agreement with those obtained using amperometric technique. © 2009 Elsevier B.V. All rights reserved.