A robust and effective composite film based on geuam gum（GG） and hydrophilic ionic liquid（ILs） 1-heptyl-3-methyl-imidazolium chloride（Cl） was prepared.The composite film can be readily used as an immobilization matrix to entrap cytochrome c（Cyt c）.UV-Vis spectroscopy showed that Cyt c retained its native structure in the composite film.A pair of well-defined and quasi-reversible redox peaks of Cyt c was obtained in 0.10 moloL-1 pH 7.0 phosphate buffer solution（PBS） at the GG-Cyt c-ILs composite film modified glassy carbon electrode（GG-Cyt c-ILs/GCE）,indicating the direct electron transfer between Cyt c and the underlying electrode.The electron transfer rate constant（ks） of Cyt c on the electrode surface was 3.87 s-1.The GG-Cyt c-ILs/GCE showed an excellent electrocatalytic activity toward the reduction of H2O2.The catalytic peak current was linear to H2O2 concentration in the range of 1.0×10-6～2.7×10-4 moloL-1,with a detection limit of 5.0×10-7 moloL-1.The apparent Michaelis-Menten constant（Km） was estimated to be 0.56 mmoloL-1.Based on the GG-ILs composite film,a third-generation reagentless biosensor could be constructed for the determination of H2O2.%用植物凝胶（GG）和亲水性离子液体（ILs）氯化1-庚基-3-甲基咪唑（[HMIM]Cl）制得一种有效的复合膜（GG-ILs）.将细胞色素c（Cyt c）包埋在该复合膜中并修饰于玻碳电极（GCE）表面,构置了细胞色素c修饰玻碳电极（GG-Cyt c-ILs/GCE）.紫外-可见光谱表明,复合膜内的Cyt c仍保持其原始构象.在pH 7.0的磷酸盐缓冲溶液中,GG-Cyt c-ILs/GCE产生了一对峰形良好、几乎对称的氧化还原峰,说明Cyt c与电极之间发生了直接电子传递,Cyt c在电极表面直接电子转移的速率常数ks为3.87 s-1.Cyt c修饰电极对过氧化氢的还原有电催化作用,其表观米氏常数Km为0.56 mmol？L–1,催化电流与过氧化氢浓度在1.0×10-6～2.7×10-4 mol？L-1范围内呈线性关系,检出限为5.0×10-7 mol？L-1.GG-ILs复合膜可用于构置第三代无试剂的H2O2传感器.
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