血红蛋白在SWCNTs-CTAB修饰电极上的直接电化学和电催化研究

Direct Electrochemistry and Electrocatalysis of Hemoglobin on SWCNTs-CTAB Modified Electrode

利用血红蛋白(Hb)结合单壁碳纳米管(SWCNTs)-十六烷基三甲基溴化铵(CTAB)制备纳米复合物修饰到玻碳电极(GCE)表面,并研究了电极上Hb的直接电化学和电催化行为.用紫外可见光谱(UV-Vis)检测键合到电极表面的Hb,可知复合膜中的Hb保持了类似于本体环境中的亚结构.通过电化学实验可知,复合膜中的Hb表现出了表面控制的可逆的直接电子转移反应.得到了标准式电位(Eθ')和表面覆盖度(Γ*)等电化学参数.在7.00×10-5mol L-1-1.26×10-3mol L-1范围内(R=0.9983,n=18)内,Hb-SWCNTs-CTAB修饰电极对过氧化氢(H2O2)表现出较好的催化还原活性,得检测限为1.96×10-5(S/N=3).该传感器具有良好的稳定性和重现性,可用于H2O2的测定.

The direct electrochemistry and electrocatalysis of hemoglobin（Hb） were investigated with the protein incorporated in the nanocomposite film of single walled carbon nanotubes（SWCNTs）-cetylramethy-lammonium bromide（CTAB） immobilized on the surface of a glassy carbon electrode（GCE）.The incorporated hemoglobin was characterized using ultraviolet visible（UV-Vis） spectroscopy,indicating the hemoglobin in SWCNTs-CTAB nanocomposite film keeps its secondary structure similar to its native state.The reactions on the surface of GCE showed a surface-controlled process with a single proton transfer at the scan rate range from 10 to 500 mV/s.According to the electrochemical methods,a series of electrochemical parameters such as formal potentials（Eθ＇） and apparent heterogeneous electron transfer rate constants（ks） were obtained.Moreover,the Hb-SWCNTs-CTAB electrode showed excellent electrocatalytic activities for the reduction of H2O2 ranging from 7.00×10-5mol L-1-1.26×10-3mol L-1（R=0.9983,n=18） with a detection limit of 1.96×10-5（S/N=3）.Furthermore,the biosensor possessed good stability and reproducibility and could be used to determine the concentration of H2O2.