An amperometric H2O2 biosensor based on cytochrome c immobilized onto nickel oxide nanoparticles/carboxylated multiwalled carbon nanotubes/polyaniline modified gold electrode

Cytochrome c was immobilized covalently onto nickel oxide nanoparticles/carboxylated multiwalled carbon nanotubes/polyaniline composite (NiO-NPs/cMWCNT/PANI) electrodeposited on gold (Au) electrode. An amperometric H2O2 biosensor was constructed by connecting this modified Au electrode along Ag/AgCl as reference and Pt wire as counter electrode to the galvanostat. The modified Au electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR). Cyclic voltammetric (CV) studies of the electrode at different stages demonstrated that the modified Au electrode had enhanced electrochemical oxidation of H2O2, which offered a number of attractive features to develop an amperometric biosensor based on split of H2O2. There was a good linear relationship between the current (mA) and H2O2 concentration in the range 3–700 μM. The sensor had a detection limit of 0.2 μM (S/N = 3) with a high sensitivity of 3.3 mA μM−1 cm−2. The sensor gave accurate and satisfactory results, when employed for determination of H2O2 in different fruit juices.

► Constructed a non-enzymatic H2O2 biosensor based on PANI/cMWCNT/NiO-NPs/Cyt c modified Au electrode. ► Sensor had a detection limit of 0.2 μM, linear range 3–700 μM and high sensitivity of 3.3 mA μM−1 cm−2. ► Employed for H2O2 determination in different fruit juices.