Direct Electrochemistry of Hemoglobin and its Electrocatalysis Based on a Carbon Nanotube Paste Electrode

A new hemoglobin (Hb) and carbon nanotube (CNT) modified carbon paste electrode was fabricated by simply mixing the Hb, CNT with carbon powder and liquid paraffin homogeneously. To prevent the leakage of Hb from the electrode surface, a Nafion film was further applied on the surface of the Hb‐CNT composite paste electrode. The modified electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Direct electrochemistry of hemoglobin in this paste electrode was easily achieved and a pair of well‐defined quasi‐reversible redox peaks of a heme Fe(III)/Fe(II) couple appeared with a formal potential (E0′) of −0.441 V (vs. SCE) in pH 7.0 phosphate buffer solution (PBS). The electrochemical behaviors of Hb in the composite electrode were carefully studied. The fabricated modified bioelectrode showed good electrocatalytic ability for reduction of H2O2 and trichloroacetic acid (TCA), which shows potential applications in third generation biosensors. A new hemoglobin (Hb) and carbon nanotubes (CNT) modified carbon paste electrode was fabricated with a Nafion film applied on the surface of Hb‐CNT composite paste electrode. Direct electrochemistry of hemoglobin in this paste electrode was achieved with a pair of well‐defined quasi‐reversible redox peak appeared. The bioelectrode showed good electrocatalytic ability to the reduction of H2O2 and trichloroacetic acid.