Nitrogen-doping to enhance the separation selectivity of glucose-based carbon dots-modified silica stationary phase for hydrophilic interaction chromatography

Doping is often used to alter or improve the properties of nanomaterials. In this work, a novel glucose-based nitrogen-doped carbon dots (Glc-NCDs)-bonded silica stationary phase (Sil-Glc-NCDs) was synthesized and characterized carefully. Glc-NCDs were prepared using glucose and aspartic acid as carbon and nitrogen sources, and then grafted on silica surface via isocyanatopropyl as linker using deep eutectic solvents as reaction medium. The synthesis was confirmed by elemental analysis, Fourier transform infrared spectroscopy and microscopic imaging techniques. And then Sil-Glc-NCDs were packed in the stainless columns for hydrophilic interaction chromatography (HILIC). Due to the synergistic effect between the functional groups of doped carbon dots, Sil-Glc-NCDs column showed enhanced separation selectivity compared with previous non-doped Sil-Glc-CDs column. Sil-Glc-NCDs column can be used for separation of base, nucleosides and antibiotics etc. This column was successfully applied to determine the content of roxithromycin in the capsule, which was found that the concentration was 2.45 mg/mL.