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 d eveloped based on the co-immobilization of catalase and methylene blue on a n Al2O3 sol-gel fabricated glassy carbon electrode. The membrane structure; of the sol-gel-immobilized catalase and methylene blue was studied with sca nning electron microscopy. Cyclic voltammetric and amperometric measurement s demonstrated that methylene blue co-immobilized with catalase in this way displayed good stability and efficiently shuttled electron between the imm obilized enzyme and the electrode. Electrocatalytic reduction of H2O2 at th e electrode was evaluated with respect to solution pH, operating potential and selectivity.:The biosensor was stable at least for 3 weeks.