title: Direct electrochemistry of hemoglobin immobilized on hydrophilic ionic liquid-chitosan-ZrO2 nanoparticles composite film with carbon ionic liquid electrode as the platform.
abstract: A stable composite film composed of 1-butyl-3-methyl-imidazolium tetrafluoroborate, chitosan, zirconia nanoparticles and the hemoglobin (Hb) was cast on the surface of an ionic liquid of an N-butylpyridinium hexafluorophosphate modified carbon paste electrode to fabricate a modified electrode. Scanning electron microscopy images of the modified electrode indicated that there was a dendritic structure on the modified electrode, and UV-Vis and FT-IR spectra showed that Hb in the composite film retained its native structure. Voltammetric experiments at the modified electrode showed that, in a pH 7.0 phosphate buffer solution, a pair of well-defined and quasi-reversible redox voltammetric peaks was obtained with the formal potential located at -0.216 V. The electrochemical parameters of Hb in the composite film were further carefully calculated: the electron-transfer rate constant was 0.52 s(-1) and the charge transfer coefficient was 0.34. The catalytic reduction peak current had a linear relationship with the concentration of trichloroacetic acid (TCA) in the range from 0.2 to 10.3 mmol/L with a detection limit of 66.7 µmol/L. Therefore, the composite film as a novel matrix opened up a possibility for further study on the design of enzymatic biosensors with potential applications.
authors.affiliation: Institute of Analytical Science, Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi’an, Shaanxi 710069, PR China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Qiao
authors.forename: Ruifang
authors.initials: R
authors.lastname: Gao
authors.forename: Jianbin
authors.initials: J
authors.lastname: Zheng
mesh_terms: D002244:Carbon / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006454:Hemoglobins / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D008567:Membranes, Artificial; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D014238:Trichloroacetic Acid / Q000032:analysis; D015040:Zirconium / Q000737:chemistry*
chemical_list: C419324:1-butyl-3-methylimidazolium tetrafluoroborate; D006454:Hemoglobins; D007093:Imidazoles; D052578:Ionic Liquids; D008567:Membranes, Artificial; D014238:Trichloroacetic Acid; D002244:Carbon; D048271:Chitosan; D015040:Zirconium; C028541:zirconium oxide