Synergistic effect of zirconium phosphate and Au nanoparticles on direct electron transfer of hemoglobin on glassy carbon electrode

Abstract

The direct electron transfer of hemoglobin (Hb) was successfully realized on Au–zirconium phosphate nanocomposite (Au–ZrP) modified glassy carbon electrode (GCE) based on the synergistic effect between ZrP and Au nanoparticles. The interaction between Hb and Au–ZrP was studied by UV–Vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. A couple of stable and well-defined redox peaks of Hb immobilized on Au–ZrP was observed at about −134 and 35 mV in pH 6.0 buffers. Moreover, the immobilized Hb showed excellent electrocatalysis to the reduction of H 2O 2, which was used to construct H 2O 2 sensors. The obtained sensor could determine H 2O 2 from 15 μmol l −1 to 0.48 mmol l −1 with detection limit of 7.4 μmol l −1( S/ N = 3). Its apparent Michaelis–Menten constant, K app M , was 0.65 mmol l −1.