Graphene quantum dots/β-cyclodextrin nanocomposites: A novel electrochemical chiral interface for tryptophan isomer recognition

Graphene quantum dots (GQDs) were prepared by pyrolysis of citric acid, and then incorporated into beta-cyclodextrin (beta-CD) via H-bonds between the oxygen-containing groups on GQDs and the hydroxyl groups on beta-CD. The nanocomposites of GQDs and beta-CD (GQDs/beta-CD) were negatively charged due to the ionization of carboxyl groups of GQDs, and therefore they could be effectively electrodeposited onto a glassy carbon electrode (GCE). The electrodeposited GQDs/beta-CD were optically active due to the introduction of beta-CDs with well-defined hydrophobic central cavities, and it was employed as an electrochemical chiral interface for enantiorecognition of typtophan (Trp) isomers. (C) 2015 Elsevier B.V. All rights reserved.