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Direct Electrochemistry of Hemoglobin on Single‐Walled Carbon Nanotubes Modified Carbon Ionic Liquid Electrode and Its Electrocatalysis
Author(s) -
Sun Wei,
Li Xiaoqing,
Zhai Ziqin,
Jiao Kui
Publication year - 2008
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.200804371
Subject(s) - ionic liquid , hexafluorophosphate , electrochemistry , electron transfer , electrocatalyst , carbon nanotube , cyclic voltammetry , nafion , electrode , chemistry , redox , inorganic chemistry , materials science , catalysis , nanotechnology , organic chemistry
Abstract In this article we report on the fabrication of a carbon ionic liquid electrode (CILE) by using a room temperature ionic liquid of 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF 6 ) as binder. It was further modified by single‐walled carbon nanotubes (SWCNTs) to get a SWCNTs modified CILE denoted as SWCNTs/CILE. The redox protein of hemoglobin (Hb) was further immobilized on the surface of SWCNTs/CILE with the help of Nafion film. UV‐vis and FT‐IR spectra indicated that the immobilized Hb retained its native conformation in the composite film. The direct electrochemistry of Hb on the SWCNTs/CILE was carefully studied in pH 7.0 phosphate buffer solution (PBS). Cyclic voltammetric results indicated that a pair of well‐defined and quasireversible voltammetric peaks of Hb heme Fe(III)/Fe(II) was obtained with the formal potential ( E °') at −0.306 V (vs. SCE). The electrochemical parameters such as the electron transfer coefficient ( α ), the electron transfer number ( n ) and the apparent heterogeneous electron transfer rate constant ( k s ) were calculated as 0.34, 0.989 and 0.538 s −1 , respectively. The fabricated Hb modified electrode showed good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) in the concentration range from 20.0 to 150.0 mmol/L with the detection limit of 10.0 mmol/L (3 σ ).