Electrochemical xanthine biosensor based on zinc oxide nanoparticles‒ multiwalled carbon nanotubes‒1,4-benzoquinone composite

Abstract

Zinc oxide nanoparticles (ZnONPs), multiwalled carbon nanotubes (MWCNTs) and 1,4-benzoquinone (BQ) dispersed in chitosan (CS) matrix were used to construct a xanthine biosensor.Xanthine oxidase (XOx) was immobilized onto BQ-MWCNTs-ZnO–CS composite modified glassy carbonelectrode (GCE) using glutaraldehyde as the crosslinking agent. The parameters of the constructionprocess and the experimental variables for the biosensor were optimized. The xanthine biosensorshowed optimum response within 10 s, and the sensitivity was 39.4 μA/mMcm2 at +0.25 V (vs.Ag/AgCl). The linear working range of the biosensor was found to be 9.0×10−71.1×10−4 M with adetection limit of 2.1×10-7 M. The biosensor exhibited good long-term stability and reproducibility.The presented biosensor was also used for monitoring the freshnesses of chicken and beef flesh.