AN AMPEROMETRIC BIOSENSOR FOR HYDROGEN PEROXIDASE BASED ON THE CO-IMMOBILIZATION OF CATALASE AND METHYLENE BLUE IN AN AL₂O₃ SOL-GEL MODIFIED ELECTRODE

Abstract

A novel biosensor for the amperometric detection of hydrogen peroxide was developed based on the co-immobilization of catalase and methylene blue on an Al₂O₃ sol-gel fabricated glassy carbon electrode. The membrane structure of the sol-gel-immobilized catalase and methylene blue was studied with scanning electron microscopy. Cyclic voltammetric and amperometric measurements demonstrated that methylene blue co-immobilized with catalase in this way displayed good stability and efficiently shuttled electron between the immobilized enzyme and the electrode. Electrocatalytic reduction of H₂O₂ at the electrode was evaluated with respect to solution pH, operating potential and selectivity. The biosensor was stable at least for 3 weeks.

Keywords:

• Al₂O₃sol-gel
• Catalase peroxidase
• Methylene blue
• H₂O₂ detection

ACKNOWLEDGMENTS

This work was supported by the National Science Foundation of China (Projects 39970195 and 29905001) and the Electroanalytical Chemistry Open Laboratory of Changchun Institute of Applied Chemistry, Chinese Academy of Sciences.