Graphene Oxide-Assisted Dispersion of Carbon Nanotubes in Sulfonated Chitosan-Modified Electrode for Simultaneous Detections of Sodium Nitrite, Hydroquinone, and Catechol

Abstract

Graphene oxide (GO) and carbon nanotubes (CNT) were dispersed in chitosan (CS) or sulfonated chitosan (sCS) aqueous solution followed by casting films on glassy carbon electrodes (GCE) to investigate the electrocatalytic activities of the films by cyclic voltammetry (CV) to develop electrochemical sensors for three food additives including NaNO2, hydroquinone, and catechol by cyclic voltammetry (CV). The effects of the water-soluble GO and sCS on the electrocatalytic activities of the modified electrodes and the detection abilities for the three analytes were studied. CV curves revealed that the GO/CNT/CS/GCE exhibited higher electrocatalytic activity and selective detection ability for the three analytes than the CNT/CS/GCE, GO/CS/GCE, CS/GCE, and bare GCE. The high electrocatalytic activity of the modified electrode was attributed to the well GO-assisted dispersion of the conductive CNT in the GO/CNT/CS nanocomposite film. By replacing CS with sCS, the GO/CNT/sCS/GCE exhibited more enhanced electrocatalytic activities than the GO/CNT/CS/GCE toward the oxidations of the three analytes. The enhanced electrocatalytic activities were attributed to the expandable sCS in aqueous solutions of analytes leading to enhanced porosity in the GO/CNT/sCS films. The GO/CNT/sCS 5/5/50-modified electrodes for detections of the three food additives exhibited relatively wide linear concentration ranges and relatively low limits of detections compared with those reported in literature.