A novel hydrogen peroxide biosensor was obtained by successfully immobilizing horseradish peroxidase (HRP) on a glassy carbon (GC) electrode, which was modified with multi-walled carbon nanotubes (MWNT) and alizarin red (AR). Then the biosensor was immerged in 3% glutaraldehyde (GA) in order to overcome the swelling and improve the stability of the gelatin membrane. The experimental condition was optimized, and the electrochemistry behavior of the HRP/AR/MWNT/GC biosensor in PBS (pH 7.0) and H₂O₂ was discussed. The biosensor displayed rapid response and expanded linear response range from 5.0×10^－6 to 1.0×10^－3 mol/L (R＝0.9932) with detection limit of 1.0×10^－7 mol/L in PBS (pH 7.0), as well as acceptable preparation reproducibility and excellent stability.

Key words: multi-walled carbon nanotube, alizarin red, gelatin, horseradish peroxidase, glutaraldehyde