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

摘要

Graphene oxide (GO) and carbon nanotubes (CNT) were dispersed in chitosan (CS) or sulfonatedchitosan (sCS) aqueous solution followed by casting films on glassy carbon electrodes (GCE) toinvestigate the electrocatalytic activities of the films by cyclic voltammetry (CV) to developelectrochemical sensors for three food additives including NaNO2, hydroquinone, and catechol bycyclic voltammetry (CV). The effects of the water-soluble GO and sCS on the electrocatalyticactivities of the modified electrodes and the detection abilities for the three analytes were studied. CVcurves revealed that the GO/CNT/CS/GCE exhibited higher electrocatalytic activity and selectivedetection 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-assisteddispersion 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/GCEtoward the oxidations of the three analytes. The enhanced electrocatalytic activities were attributed tothe expandable sCS in aqueous solutions of analytes leading to enhanced porosity in the GO/CNT/sCSfilms. The GO/CNT/sCS 5/5/50-modified electrodes for detections of the three food additivesexhibited relatively wide linear concentration ranges and relatively low limits of detections comparedwith those reported in literature.