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 inchitosan (CS) matrix were used to construct a xanthine biosensor. Xanthineoxidase (XOx) was immobilized onto BQ-MWCNTs-ZnO–CS composite modified glassycarbon electrode (GCE) using glutaraldehyde as the crosslinking agent. Theparameters of the construction process and the experimental variables for thebiosensor were optimized. The xanthine biosensor showed optimum response within10 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 9.0×10−7-1.1×10−4M with a detection limit of 2.1×10-7 M. The biosensor exhibited goodlong-term stability and reproducibility. The presented biosensor was also usedfor monitoring the freshnesses of chicken and beef flesh.