期刊
TALANTA
卷 79, 期 3, 页码 780-786出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.talanta.2009.05.002
关键词
Fe3O4 nanoparticles; Direct electrochemistry; Electrocatalysis; Hemoglobin; Hydrogen peroxide
资金
- National Natural Science Foundation of China [20775088]
- Foundation of State Key Laboratory of Environmental Chemistry and Ecotoxicology
- Research Center for Eco-Environmental Sciences
- Chinese Academy of Sciences [KF2008-06]
Magnetic nanoparticles (Fe3O4) were synthesized by a chemical coprecipitation method. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to confirm the crystallite structure and the particle's radius. The Fe3O4 nanoparticles and chitosan (CS) were mixed to form a matrix in which haemoglobin (Hb) can be immobilized for the fabrication of H2O2 biosensor. The Fe3O4-CS-Hb film exhibited a pair of well-defined and quasi-reversible cyclic voltammetric peaks due to the redox of Hb-heme Fe (III)/Fe (II) in a pH 7.0 phosphate buffer. The formal potential of Hb-heme Fe(III)/Fe(II) couple varied linearly with the increase of pH in the range of 4.0-10.0 with a slope of 46.5 mV pH(-1), indicating that electron transfer was accompanied with single proton transportation in the electrochemical reaction. The surface coverage of Hb immobilized on Fe3O4-CS film glassy carbon electrode was about 1.13 x 10(-10) Mol cm(-2). The heterogeneous electron transfer rate constant(k(s)) was 1.04 s(-1), indicating great facilitation of the electron transfer between Hb and magnetic nanoparticles-chitosan modified electrode. The modified electrode showed excellent electrocatalytic activity toward oxygen and hydrogen peroxide reduction. The apparent Michaelis-Menten constant K-M(app) for H2O2 was estimated to be 38.1 mu mol L-1. (C) 2009 Elsevier B.V. All rights reserved.
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