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Direct Electrochemistry and Electrocatalysis of Hemoglobin Based on Nafion‐Room Temperature Ionic Liquids‐Multiwalled Carbon Nanotubes Composite Film
Author(s) -
Zhang Ya,
Zheng Jianbin
Publication year - 2011
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201190141
Subject(s) - nafion , chemistry , electrocatalyst , ionic liquid , electrochemistry , catalysis , biosensor , carbon nanotube , electrode , composite number , detection limit , glassy carbon , redox , inorganic chemistry , electron transfer , chemical engineering , nuclear chemistry , cyclic voltammetry , organic chemistry , chromatography , composite material , materials science , biochemistry , engineering
A robust and effective composite film combined the benefits of Nafion, room temperature ionic liquid (RTIL) and multi‐wall carbon nanotubes (MWNTs) was prepared. Hemoglobin (Hb) was successfully immobilized on glassy carbon electrode surface by entrapping in the composite film. Direct electrochemistry and electrocatalysis of immobilized Hb were investigated in detail. A pair of well‐defined and quasi‐reversible redox peaks of Hb was obtained in 0.10 mol·L −1 pH 7.0 phosphate buffer solution (PBS), indicating that the Nafion‐RTIL‐MWNTs film showed an obvious promotion for the direct electron transfer between Hb and the underlying electrode. The immobilized Hb exhibited an excellent electrocatalytic activity towards the reduction of H 2 O 2 . The catalysis current was linear to H 2 O 2 concentration in the range of 2.0×10 −6 to 2.5×10 −4 mol·L −1 , with a detection limit of 8.0×10 −7 mol·L −1 ( S / N =3). The apparent Michaelis‐Menten constant (K m app ) was calculated to be 0.34 mmol·L −1 . Moreover, the modified electrode displayed a good stability and reproducibility. Based on the composite film, a third‐generation reagentless biosensor could be constructed for the determination of H 2 O 2 .