Analytical Sciences

Direct Electrochemistry and Elctrocatalytic Activity of Hemoglobin at CdTe Nanoparticle/Nafion Film-modified Electrode

Zhan WANG, Qiao XU, Hai-Qiao WANG, Zhao-Hui YIN, Jiu-Hong YU, and Yuan-Di ZHAO

Wuhan National Laboratory for Optoelectronics, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China

Water-soluble CdTe nanoparticles and hemoglobin (Hb) were immobilized on a glassy carbon (GC) electrode with Nafion. The direct electrochemistry of Hb on this surface was studied. The results indicated that CdTe nanoparticles could effectively promote the direct electron transfer of Hb at the interface of a electrode. The average surface coverage of Hb on the surface could be calculated as 2.63×10⁻⁹ mol/cm², the heterogeneous electron transfer rate constant, k, was calculated as 0.068 s⁻¹ and the transfer coefficient, α, was 0.59, further study indicated that immobilized Hb still kept its catalytic activity to H₂O₂ reduction. The apparent Michaelis-Menten constant was calculated to be 17.7 μM. It was also found that the modified electrode could be used as a sensor for H₂O₂; the linear range of detection was 5.0×10⁻⁶ − 4.5×10⁻⁵ M, with a detection limit of 8.4×10⁻⁷ M. The sensor exhibited high sensitivity, reproducibility and stability.

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