An amperometric biosensor for hydrogen peroxidase based on the co-immobilization of catalase and methylene blue in an Al2O3 sol-gel modified electrode

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.