Direct electrochemistry and electrocatalysis of cytochrome c based on chitosan-room temperature ionic liquid-carbon nanotubes composite |
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Authors: | Ya Zhang Jianbin Zheng |
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Affiliation: | a Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi’an, Shaanxi 710069, China b Department of Chemistry and Chemical Engineering, Yulin College, Yulin, Shaanxi 719000, China |
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Abstract: | A robust and effective composite film combined the benefits of room temperature ionic liquid (RTIL), chitosan (Chi) and multi-wall carbon nanotubes (MWNTs) was prepared. Cytochrome c (Cyt c) was successfully immobilized on glassy carbon electrode (GCE) surface by entrapping in the composite film. Direct electrochemistry and electrocatalysis of immobilized Cyt c were investigated in detail. A pair of well-defined and quasi-reversible redox peaks of Cyt c was obtained in 0.1 mol L−1 pH 7.0 phosphate buffer solution (PBS), indicating the Chi-RTIL-MWNTs film showed an obvious promotion for the direct electron transfer between Cyt c and the underlying electrode. The immobilized Cyt c exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis current was linear to H2O2 concentration in the range of 2.0 × 10−6 to 2.6 × 10−4 mol L−1, with a detection limit of 8.0 × 10−7 mol L−1 (S/N = 3). The apparent Michaelis-Menten constant (Km) was calculated to be 0.45 ± 0.02 mmol L−1. Moreover, the modified electrode displayed a rapid response (5 s) to H2O2, and possessed good stability and reproducibility. Based on the composite film, a third-generation reagentless biosensor could be constructed for the determination of H2O2. |
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Keywords: | Cytochrome c Room temperature ionic liquid Multi-walled carbon nanotubes Electrochemistry Electrocatalysis |
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