Direct electron transfer of hemoglobin in a CdS nanorods and Nafion composite film on carbon ionic liquid electrode

详细信息    查看全文

• 作者：Wei Sun ; D ; an Wang ; Guicun Li ; Ziqin Zhai ; Ruijun Zhao ; Kui Jiao
• 关键词：1-Butyl-3-methylimidazolium hexafluorophosphate ; Hemoglobin ; Direct electrochemistry ; Carbon paste electrode ; Ionic liquid
• 刊名：Electrochimica Acta
• 出版年：2008
• 出版时间：30 November 2008
• 年：2008
• 卷：53
• 期：28
• 页码：8217-8221
• 全文大小：659 K

文摘

In this paper the direct electron transfer of hemoglobin (Hb) was carefully investigated by using a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆) modified carbon paste electrode (CILE) as the basal working electrode. Hb was immobilized on the surface of CILE with the nanocomposite film composed of Nafion and CdS nanorods by a step-by-step method. UV–vis and FT-IR spectra showed that Hb in the composite film remained its native structure. The direct electrochemical behaviors of Hb in the composite film were further studied in a pH 7.0 phosphate buffer solution (PBS). A pair of well-defined and quasi-reversible cyclic voltammetric peaks of Hb was obtained with the formal potential (E⁰′) at −0.295 V (vs. SCE), which was the characteristic of heme Fe(III)/Fe(II) redox couples. The direct electrochemistry of Hb was achieved on the modified electrode and the apparent heterogeneous electron transfer rate constant (k_s) was calculated to be 0.291 s⁻¹. The formal potentials of Hb Fe(III)/Fe(II) couple shifted negatively with the increase of buffer pH and a slope value of −45.1 mV/pH was got, which indicated that one electron transfer accompanied with one proton transportation. The fabricated Hb sensor showed good electrocatalytic manner to the reduction of trichloroacetic acid (TCA).