Polypyrrole–multiwalled carbon nanotubes composites as immobilizing matrices of ascorbate oxidase for the facile fabrication of an amperometric vitamin C biosensor |
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| Authors: | Haohua He Jingkun Xu Ming Liu Ruirui Yue |
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| Affiliation: | 1. Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Key Laboratory of Physiology, Ecology and Cultivation of Double Cropping Rice, Ministry of Agriculture, Jiangxi Agricultural University, Nanchang 330045, China;2. Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013, China |
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| Abstract: | An amperometric vitamin C biosensor was facilely fabricated by the immobilization of ascorbate oxidase (AO) on polypyrrole (PPy)–multiwalled carbon nanotubes (MWCNTs) composites with a one‐step electrodeposition technique in a 0.05M phosphate buffer solution (pH 6.5). The cyclic voltammetry, IR spectral analysis, electrochemical impedance spectroscopy, and scanning electron microscopy measurements indicated that AO was successfully immobilized on the PPy–MWCNT composites. The optimization of the biosensor parameters, including the working potential, pH, and temperature, was investigated in detail. The proposed biosensor showed a linear range of 5 × 10?5 to 2 × 10?2 M with a detection limit of 0.3 μM, a sensitivity of 25.9 mA mM?1 cm?2, and a current response time less than 20 s under the optimized conditions. The apparent Michaelis–Menten constant together with the apparent activation energy indicated that the proposed biosensor exhibited a high bioaffinity and a good enzyme activity. In addition, the biosensor also showed good operational and storage stabilities. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 |
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| Keywords: | conducting polymers carbon nanotubes electrochemistry enzymes sensors |
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