Graphene Quantum Dots Incorporated into β-cyclodextrin: a Novel Polymeric Nanocomposite for Non-Enzymatic Sensing of L-Tyrosine at Physiological pH

Abstract

Graphene quantum dot-β-cyclodextrin modified glassy carbon electrode was used as a new nanosensor for determination of L-tyrosine (L-Tyr). It was found that graphene quantum dot-β-cyclodextrin has been stably electrodeposited on glassy carbon electrode modified by simple technique. The cyclic voltammograms of the modified electrode in an aqueous solution displayed a pair of well-defined, stable and irreversible reductive/oxidation redox systems. The apparent electron transfer rate constant (k_s) and transfer coefficient (α) determined by cyclic voltammetry were approximately equal to 8.0 s^–1 and 0.7, respectively. The modified electrode showed excellent catalytic activity towards the oxidation of L-Tyr at positive potential in buffer solution. The nanosensor also displayed fast response time, high sensitivity, low detection limit and a remarkably positive potential oxidation of L-Tyr that decreased the effect of interferences in analysis.