Preparation and Electrochemical Characterization of an Enzyme Electrode Based on Catalase Immobilized onto a Multiwall Carbon Nanotube‐Thionine Film |
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| Authors: | Sedigheh Hashemnia Mahbubeh Eskanari |
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| Affiliation: | Department of Chemistry, Persian Gulf University, Bushehr 75169, Iran |
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| Abstract: | The present study was aimed at investigating the use of a mixture multiwall carbon nanotube (MWCNT) and thionine (Th) dye in designing of a thionine‐based electrochemical biosensor containing catalase (Ct) enzyme (MWCNT‐Nafion‐Th/Ct) onto a glassy carbon electrode (GCE). The effects of pH, MWCNT concentration and thionine concentration on electrochemical response were explored for optimum analytical performance. The modified electrode exhibited a pair of well‐defined, quasi‐reversible peaks at formal potential (Eo′) = ‐0.218 ± 0.017 V vs. Ag/AgCl corresponding to the Thox/Thred redox couples in the presence of MWCNT, Nafion, and Ct. The electrochemical parameters, including charge‐transfer coefficient (0.36), and apparent heterogeneous electron transfer rate constant (4.28 ± 0.26 s?1) were determined. Using differential pulse voltammetry, the prepared enzyme electrode exhibited a linear response to hydrogen peroxide (H2O2) in the range of 10.0‐100.0 μM with a detection limit 8.7 μM and a sensitivity of 6051.0 μA mM?1 cm?2. |
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| Keywords: | Glassy carbon electrode Catalase Thionine Multiwall carbon nanotube Electron mediator |
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