Amperometric detection of dopamine based on tyrosinase-SWNTs-Ppy composite electrode |
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Authors: | Kyoungseon Min |
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Institution: | School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Republic of Korea |
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Abstract: | A novel 3-dimensional single wall carbon nanotubes (SWNTs)-polypyrrole (Ppy) composite was prepared as an electrode by chemically polymerizing polypyrrole onto SWNTs using a LiClO4 oxidant. This composite electrode was characterized by scanning electron microscopy (SEM) and cyclic voltammetry with 1 mM Fe(CN)6]−3/Fe(CN)6]−4. The SWNTs were thickly coated with chemically polymerized polypyrrole and the composite had many surface pores and crevices which could enhance mass transfer. The SWNTs-Ppy composite electrode showed a large specific surface area (30 m2/g) and a good reproducible current response, at about 100 times the peak current of a glassy carbon electrode (GCE). The diffusion coefficient was calculated to be 4.81 × 10−6 cm2/s. As a biosensor application, tyrosinase was immobilized on the functionalized SWNTs and tyrosinase-SWNTs-Ppy composite was prepared in the same manner. This tyrosinase-SWNT-Ppy composite electrode was used for amperometric detection of dopamine in the presence of ascorbic acid and showed high sensitivity (467 mA/M cm2) and lower detection limit (5 μM) compared to previous reports. |
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Keywords: | 3-Dimensional composite electrode Tyrosinase Chemically polymerized polypyrrole Single wall carbon nanotube Dopamine sensor Ascorbic acid |
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