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

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.