Fabrication of an electrochemical biosensor based on Nafion/horseradish peroxidase/Co3O4 NP/CILE and its electrocatalysis

Abstract

This paper focuses on the investigation of direct electrochemistry and electrocatalysis of horseradish peroxidase (HRP) on Co3O4 nanoparticles (NPs) decorated carbon ionic liquid electrode (CILE) as an electrochemical biosensor for determinations of trichloroacetic acid (TCA) and sodium nitrite (NaNO2). Co3O4 NPs were served to bridge the gaps between electron transport of electrochemical active site of HRP to the electrode with the ability to enhance the loading capacity of HRP on the electrode. Various material characterization techniques such as scanning electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectroscopy were used to check the structure, morphology and crystal form of Co3O4 NP. Spectroscopic data testified that no denaturation occurred in the structure of HRP. Electrochemical performances of Nafion/HRP/Co3O4/CILE were conducted in pH 3.0 phosphate buffer solutions, which indicated that electron communication was achieved with the appearance of one well-distinct peak couple. Low detection limits and wide linear ranges were obtained in electrocatalytic investigations for the different substrates including TCA and NaNO2 with the real samples detected successfully.