Construction of cyclodextrin functionalized nitrogen-doped graphene quantum dot electrochemical sensing interface for recognition of tryptophan isomers

• DOI: 10.1016/j.matchemphys.2021.125086
• Publication Date: 2021-07-31T09:29:32Z
• Authors: Fang Chen; Hebing Pei; Qianqian Jia; Wei Guo; Xuejiao Zhang; Ruibin Guo; Nijuan Liu; Zunli Mo
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract Amino acids are the most common class of enantiomers, and they are also an indispensable component of life. Nitrogen-doped graphene quantum dots (NGQDs) were prepared by a top-down method. And then amide reaction was used to covalently graft aminated β-cyclodextrin (NH2-β-CD) to the edge of NGQDs. By preparing β-cyclodextrin (β-CD) functionalized nitrogen-doped graphene quantum dots (β-CD-NGQDs) and applying them to the glassy carbon electrode to construct an electrochemical sensing interface, enantiomers of tryptophan can be effectively identified. NGQDs can effectively improve the conductivity of β-CD. When chiral selectors interact with enantiomers, NGQDs can provide additional interactions, such as hydrophobic, hydrogen bonding, and electrostatic interactions to indirectly enhancing chiral recognition capabilities. β-Cyclodextrin has the ability to combine with a variety of guest molecules to form composite materials, including some amino acid molecules with different configurations. The microscopic morphology of the material was characterized by a transmission electron microscope, and it was found that the β-CD-NGQDs chiral composite material has good film-forming properties, which is beneficial to the formation of a sensing interface. At the same time, its composition and structure were also identified by X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy, ultraviolet spectroscopy, and X-ray photoelectron spectroscopy. The β-CD-NGQDs was drip-coated on the glassy carbon electrode to form a working electrode. The tested differential pulse voltammetry curves of different configurations of tryptophan showed that the chiral composite material can recognize l -tryptophan.