Evaluation of a composite nanomaterial consist of gold nanoparticles and graphene-carbon nitride as capillary electrochromatography stationary phase for enantioseparation

• A composite nanomaterial was prepared and modified as capillary stationary phase. • CD-GNPs-g-C 3 N 4 is confirmed as a viable coating for enantioseparation in CEC. • The chiral separation performance of several enantiomers are obtained. In this study, a composite nanomaterial, gold nanoparticles-graphitic carbon nitride (GNPs-g-C 3 N 4 ), composed of GNPs and g-C 3 N 4 nanosheet was synthesized and utilized as capillary coating. The composites possess both the advantages of GNPs and g-C 3 N 4 , which has many advantages such as relatively large surface and ease-to-modify. After functionalization by sulfydryl-β-cycldextrin (HS-β-CD), the CD-GNPs-g-C 3 N 4 was employed as chiral stationary phases (CSP) for enantioseparation in open tubular capillary electrochromatography (OT-CEC) mode. The composites nanomaterials and the functionalized capillaries ware characterized by scanning electron microscopy transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area measurement and N 2 adsorption–desorption isotherm. Several basic drugs were used as the model to evaluate the enantioselectivity and enantiomeric resolutions of the CSP. Compared to CD-GNPs-column and CD-g-C 3 N 4 -column, significantly enhanced separation was obtained in this OT-CEC system. Several key factors (e.g., buffer pH and applied voltage) that affect CEC performance were systematically investigated and optimized. And the reproducibility of the CD-GNPs-g-C 3 N 4 -column was evaluated. Under the optimized conditions, the maximum column efficiency of model drugs could reach 120,000 plates/m. This work is expected to provide a novel approach for designing and fabricating composite nanomaterials for chiral separation in OT-CEC.