Nafion‐Methylene Blue Functional Membrane and Its Application in Chemical and Biosensing

Abstract

A functional membrane composed of nanoparticles of methylene blue and Nafion perfluorosulfonated ion‐exchange resin (Nafion^®) was constructed and characterized by the methods of scanning electron microscope, transmission electron microscope, UV‐vis, and Fourier transform infrared. The membrane at glassy carbon electrode was directly applicable for determining H₂O₂ concentration. Furthermore, horseradish peroxidase was immobilized on the membrane, which showed a quasi‐reversible electrochemical behavior with a formal potential of −296 mV. The resulting biosensor exhibited a good stability and higher sensitivity to H₂O₂ relative to the membrane without horseradish perioxidase. The linear range of this biosensor for H₂O₂ determination was from 2×10⁻⁵ to 7×10⁻³ M, with detection limit of 7×10⁻⁶ M.

Keywords:

• Methylene blue
• Nafion
• functional membrane
• biosensor
• HRP
• hydrogen peroxide

The authors thank Dr. Parviz Nuroozi and S.M.H Hashemi. (Faculty of Science, University of Tehran, Iran) for their collaborations. Financial support provided by the Research Council of the University of Tehran and Iran National Science Foundation (INSF) is gratefully appreciated.