title: Electrochemistry of hemoglobin entrapped in a Nafion/nano-ZnO film on carbon ionic liquid electrode.
abstract: A stable composite film composed of the ionomer Nafion, the ZnO nanoparticle and the protein hemoglobin was cast on the surface of an ionic liquid modified carbon paste electrode (CILE) to establish a modified electrode denoted as Nafion/nano-ZnO/Hb/CILE. UV-vis and FT-IR spectrum showed that hemoglobin in the film retained its native conformation. The electrochemical behaviors of hemoglobin entrapped in the film were carefully investigated with cyclic voltammetry. A pair of well-defined and quasi-reversible redox voltammetric peaks for Hb Fe(III)/Fe(II) was obtained with the standard potential (E(0)') located at -0.344 V (vs. SCE) in phosphate buffer solution (PBS, pH 7.0), which was attributed to the direct electron transfer of Hb with electrode in the microenvironments of ZnO nanoparticle and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The electrochemical parameters of Hb in the composite film were further carefully calculated with the results of the electron-transfer rate constant (k(s)) as 0.139 s(-1), the charge transfer coefficient (alpha) as 0.413 and the number of electron transferred (n) as 0.95. The Hb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid (TCA).
authors.affiliation: Key Laboratory of Eco-Chemical Engineering (QUST) of Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, P.R. China. sunwei@qust.edu.cn
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.forename: ZiQin
authors.initials: Z
authors.lastname: Zhai
authors.forename: DanDan
authors.initials: D
authors.lastname: Wang
authors.forename: ShuFeng
authors.initials: S
authors.lastname: Liu
authors.forename: Kui
authors.initials: K
authors.lastname: Jiao
mesh_terms: D002244:Carbon; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D006454:Hemoglobins / Q000737:chemistry*; D052578:Ionic Liquids; D010084:Oxidation-Reduction; D014238:Trichloroacetic Acid / Q000737:chemistry
chemical_list: D006454:Hemoglobins; D052578:Ionic Liquids; D014238:Trichloroacetic Acid; D002244:Carbon