Application of Fe3O4 mesoporous sphere modified carbon ionic liquid electrode as electrochemical hemoglobin biosensor

A new electrochemical hemoglobin (Hb) biosensor was constructed based on a Fe3O4 mesoporous spheres modified carbon ionic liquid electrode (CILE), which showed excellent electrocatalytic ability towards the reduction of trichloroacetic acid. CILE was prepared by using N-hexylpyridinium hexafluorophosphate (HPPF6) as the modifier and the binder in the carbon paste. Ultraviolet-visible and Fourier transform infrared spectroscopic results indicated that Hb molecules retained the native structure in the chitosan and Fe3O4 mesoporous spheres composite film. Electrochemical results indicated that a pair of well-defined redox peaks appeared in 0.1 mol/L phosphate buffer solution (PBS) with the formed potential (E-0') as -0.287 V (vs. SCE), indicating that the direct electron transfer of Hb in the composite film was realized. Electrochemical behaviors of Hb were carefully investigated with the electrochemical parameters such as electron transfer coefficient (alpha), electron transfer number (n), and heterogeneous electron transfer rate constant (k(s)) calculated. Due to the specific characteristics of Fe3O4 mesoporous spheres present on the electrode surface, the electron transfer rate of Hb was greatly promoted. The Hb modified electrode exhibited excellent electrocatalytic properties with wider linear range and lower detection limit. (C) 2012 Elsevier B.V. All rights reserved.