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Application of NiMoO 4 Nanorods for the Direct Electrochemistry and Electrocatalysis of Hemoglobin with Carbon Ionic Liquid Electrode
Author(s) -
Hu Song,
Cao Lili,
Sun Zhaolan,
Xiang Jun,
Lu Ming,
Sun Wei
Publication year - 2012
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201100508
Subject(s) - ionic liquid , electrochemistry , nanorod , cyclic voltammetry , electron transfer , charge transfer coefficient , chemistry , electrocatalyst , redox , electrode , hexafluorophosphate , inorganic chemistry , materials science , nanotechnology , catalysis , organic chemistry
In this paper NiMoO 4 nanorods were synthesized and used to accelerate the direct electron transfer of hemoglobin (Hb). By using an ionic liquid (IL) 1‐butylpyridinium hexafluorophosphate (BPPF 6 ) modified carbon paste electrode (CILE) as the basic electrode, NiMoO 4 nanorods and Hb composite biomaterial was further cast on the surface of CILE and fixed by chitosan (CTS) to establish a modified electrode denoted as CTS/NiMoO 4 ‐Hb/CILE. UV‐vis and FT‐IR spectroscopic results showed that Hb in the film retained its native structures without any conformational changes. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with a pair of well‐defined and quasi‐reversible redox voltammetric peaks appearing in phosphate buffer solution (PBS, pH 3.0), which was attributed to the direct electrochemistry of the electroactive center of Hb heme Fe(III)/Fe(II). The results were ascribed to the specific characteristic of NiMoO 4 nanorods, which accelerated the direct electron transfer rate of Hb with the underlying CILE. The electrochemical parameters of Hb in the composite film were further carefully calculated with the results of the electron transfer number ( n ) as 1.08, the charge transfer coefficient ( α ) as 0.39 and the electron‐transfer rate constant ( k s ) as 0.82 s −1 . The Hb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid (TCA) in the concentration range from 0.2 to 26.0 mmol/L with a detection limit of 0.072 mmol/L (3 σ ), and H 2 O 2 in the concentration range from 0.1 to 426.0 µmol/L with a detection limit of 3.16×10 −8 mol/L (3 σ ).