期刊
SENSORS AND ACTUATORS B-CHEMICAL
卷 155, 期 2, 页码 722-729出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.snb.2011.01.037
关键词
Carbon felt; Bioelectrocatalytic flow-through detector; Horseradish peroxidase; Direct electron transfer; Cyanuric chloride
资金
- Ministry of Education, Science and Culture of Japan
- High-Tech Research Center of Saitama Institute of Technology
Horseradish peroxidase (HRP) was chemically modified using cyanuric chloride (CC) as a linking agent onto a carbon felt (CF), which is a microelectrode ensemble of micro carbon fiber (>7 mu m, diameter) with a random three-dimensional structure. The resulting HRP-modified CF (HRP-ccCF) exhibited well-defined redox waves based on the HRP heme Fe-III/Fe-II redox couple at -0.23 V vs. Ag/AgCl (at pH 7.0), while the HRP-adsorbed CF (HRP-CF) showed no apparent redox couple in the same potential range, indicating that the chemical modification of HRP via CC facilitated the direct electron transfer (DET) between HRP and CF. The apparent heterogeneous electron transfer rate constant k(s), was estimated to be 35 s(-1). Cyclic voltammetry and electrochemical impedance spectroscopy revealed that the interfacial properties (i.e., structure, morphology of enzyme-layer) of covalently modified HRP (HRP-ccCF) and physically adsorbed HRP (HRP-CF) are different, resulting in the difference in the electron transfer properties. The HRP-ccCF was successfully used as a working electrode unit in bioelectrocatalytic flow-through detector for highly sensitive amperometric determination of H2O2. Under the optimized conditions (i.e., applied potential, 0V vs. Ag/AgCl: carrier flow rate, 3.25 ml/min; and carrier pH 7.0), the cathodic peak current of H2O2 linearly increased up to 3 mu M (sensitivity, 1.94 mu A/mu M; the detection limit, 0.08 mu M[S/N 3]) with sample through-put of ca. 90 samples/h. (C) 2011 Elsevier B.V. All rights reserved.
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