Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10559633 | Talanta | 2009 | 7 Pages |
Abstract
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 pHâ1, 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 Ã 10â10 mol cmâ2. The heterogeneous electron transfer rate constant (ks) was 1.04 sâ1, 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 KMapp for H2O2 was estimated to be 38.1 μmol Lâ1.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Na Zheng, Xia Zhou, Weiying Yang, Xiangjun Li, Zhuobin Yuan,