A REAGENTLESS BIOSENSOR HIGHLY SENSITIVE TO HYDROGEN-PEROXIDE BASED ON NEW METHYLENE-BLUE-N DISPERSED IN NAFION(R) GEL AS THE ELECTRON SHUTTLE

A reagentless biosensor highly sensitive to hydrogen peroxide was cons tructed by immobilizing horseradish peroxidase on Nafion(R)-new methyl ene blue N modified electrode. Cyclic voltammetry and chronamperometry were for the first time employed to demonstrate the feasibility of el ectron transfer between immobilized horseradish peroxidase and a glass y carbon electrode via new methylene blue N incorporated in Nafion(R) gel. Performance and characteristics of the sensor were evaluated with respect to response time, detection limit, selectivity, and dependenc e on applied potential, thickness of Nafion(R) membrane, ionic strengt h, temperature and pH as well as operating and storage stability. High sensitivity of the sensor with a detection limit of 0.5 mu M was due to high efficiency of the electron communication between immobilized h orseradish peroxidase and the electrode via new methylene blue N.