Direct Electron Transfer of Hemoglobin on a Carbon Ionic Liquid Electrode with TiO 2 Nanopatricle as Enhancer

Room temperature ionic liquids (RTILs) N‐butylpyridinium hexafluorophosphate (BPPF 6 ) modified carbon paste electrode (CILE) was fabricated and applied to adsorb the hemoglobin (Hb) and TiO 2 nanoparticles on the electrode surface step by step to form a Hb modified electrode noted as TiO 2 /Hb/CILE. UV‐Vis and FT‐IR spectra showed that Hb in the film retained its native conformations. Cyclic voltammetric experiments indicated that a pair of well‐defined quasi‐reversible redox peaks appeared with the formal potential (E 0′ ) located at −0.251 V (vs. SCE) at pH 7.0 phosphate buffer solution (PBS), which was the characteristic of heme Fe(III)/Fe(II) redox couples. Electrochemical parameters of the Hb in the film such as the electron transfer coefficient (α), the electron transfer number (n) and the standard electron transfer rate constant ( k s ) were estimated as 0.469, 0.87 and 0.635 s −1 , respectively.