Hydrogen peroxide biosensor based on the immobilization of horseradish peroxidase on γ-Al2O3 nanoparticles/chitosan film-modified electrode
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An amperometric biosensor based on horseradish peroxidase (HRP) and γ-Al2O3/chitosan composite film at a glassy carbon electrode has been developed. Hydrogen peroxide (H2O2) was detected with the aid of ferrocene monocarboxylic acid mediator to transfer electrons between the electrode and HRP. The morphology and composition of the modified electrode were characterized by scanning electron microscopy and electrochemical impedance spectroscopy. The electrochemical characteristics of the biosensor were studied by cyclic voltammetry and amperometry. The effects of HRP concentration, the applied potential, and the pH values of the buffer solution on the response of the sensor were investigated for optimum analytical performance. The proposed biosensor showed high sensitivity (0.249 A M−1 cm−2) and a fast response (<5 s) to H2O2 with the detection limit of 0.07 μM. The linear response range of the enzyme electrode to H2O2 concentration was from 0.5 to 700 μM with a correlation coefficient of 0.9998. The apparent Michaelis-Menten constant of the biosensor was calculated to be 0.818 mM, exhibiting a high enzymatic activity and affinity for H2O2.
KeywordsHorseradish peroxidase γ-Al2O3 Hydrogen peroxide Biosensor Glassy carbon electrode
This research is supported by the National Natural Science Foundation of China (No. 20975066) and the Nano-Foundation of Science and Techniques Commission of Shanghai Municipality (No.0952 nm01500), Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50102), and the Ph.D. Innovation Foundation of Shanghai University (No. SHUCX091030).