Electrochemistry of Hemoglobin in the Chitosan and TiO2 Nanoparticles Composite Film Modified Carbon Ionic Liquid Electrode and Its Electrocatalysis

Direct electron transfer of hemoglobin (Hb) in the chitosan (CTS) and TiO2 nanoparticles (nano-TiO2) composite films was achieved by using a room temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) modified carbon paste electrode (CILE) as the basal electrode. UV-Vis and FT-IR spectroscopy indicated that Hb in the film retained the native structure. Electrochemical investigation indicated that a pair of well-defined quasi-reversible redox peaks of Hb heme Fe(III)/Fe(II) was obtained with the formal potential located at -0.340 V (vs. SCE) in pH 7.0 phosphate buffer solution (PBS). The electrochemical parameters such as the electron transfer coefficient (alpha), the electron transfer number (n) and the standard electron transfer rate constant (k(s)) were got as 0.422, 0.93 and 0.117 s(-1), respectively. The fabricated CTS/nano-TiO2/Hb/CILE showed good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) and hydrogen peroxide (H2O2), which exhibited a potential application in fabricating a new kind of third generation biosensor.