An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

•Hydrogen peroxide biosensor was constructed by combining the advantageous properties of MWCNTs and Co3O4.•Incorporating Co3O4 nanoparticles into MWCNTs/gelatin film increased the electron transfer.•Co3O4/MWCNTs/gelatin/HRP/Nafion/GCE showed strong anti-interference ability.•Hydrogen peroxide was successfully determined in disinfector with an average recovery of 100.78±0.89. In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at −0.30V (vs. Ag/AgCl). The biosensor showed optimum response within 5s at pH 7.0. The optimized biosensor showed linear response range of 7.4×10−7–1.9×10−5M with a detection limit of 7.4×10−7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78±0.89.