An amperometric biosensor based on the coimmobilization of horseradish peroxidase and methylene blue on a beta-type...

A new biosensor for the amperometric detection of hydrogen peroxide was developed based on the coimmobilization of horseradish peroxidase (HRP) and methylene blue on a beta-type zeolite modified glassy carbon electrode without the commonly used bovine serum albumin-glutaraldehyde. The intermolecular interaction between enzyme and zeolite matrix was investigated using FT-IR. The cyclic voltammetry and amperometric measurement demonstrated that methylene blue co-immobilized with HRP in this way displayed good stability and could efficiently transfer electrons between immobilized HRP and the electrode. The sensor responded rapidly to H2O2 in the linear range from 2.5 x 10(-6) to 4.0 x 10(-3) M with a detection limit of 0.3 microM. The sensor was stable in continuous operation.