Electrochemical properties of chitosan/carbon nanotube/graphene composites used for detections of food additives

Abstract

Composite films of chitosan (CS), carbon nanotube (CNT), graphene oxide (GO), and reduced graphene oxide (rGO) that were cast on glassy carbon electrode (GCE) were investigated on their electrochemical properties and detections of four food additives (sodium nitrite, sodium sulfite, hydroquinone, and catechol) by cyclic voltammetry. As compared to the rGO/CNT/CS/GCE, the GO/CNT/CS/GCE, although exhibiting relatively low current intensity, exhibited selective detection ability for the four food additives. Using sulfonated chitosan (sCS) to substitute for CS, the GO/CNT/sCS/GCE exhibited much enhanced electrocatalytic properties for the four food additives. The linear detection ranges were 1.25-631 �M for sodium nitrite, hydroquinone and catechol, and 2.5-1262 �M for sodium sulfite. The detection sensitivities were 0.0408 (NaNO2), 0.0095 (Na2SO3), 0.0443 (HQ), and 0.0522 (CC) �A cm-2 �M-1. The detection limits were 0.06 �M (NaNO2), 0.082 �M (Na2SO3), 0.026 �M (HQ), and 0.026 �M (CC).