Chiral separation of fluoroquinolones by capillary electrophoresis using glucosamine-functionalized carbon quantum dots as a Pseudostationary phase

Fluoroquinolones are a class of widely used antibiotics, most of which contain chiral centers. Significant differences exist between their enantiomers in terms of antimicrobial activity, pharmacokinetics, and toxicity. In this study, glucosamine chiral-functionalized carbon quantum dots (GA-CQDs) were successfully synthesized and employed as a pseudostationary phase. By optimizing the chromatographic conditions, an efficient and novel chiral separation platform based on capillary electrophoresis (CE) was established for the enantioseparation of six fluoroquinolones. Compared to the CE system using free glucosamine solely as the chiral selector, the CE system employing GA-CQDs as a pseudostationary phase demonstrated a substantial improvement in chiral resolution (Rs) for all six model analytes (Ofloxacin: 1.56 → 9.21; Pazufloxacin: 0 → 8.53; Prulifloxacin: 1.38 → 7.58; Lomefloxacin: 1.01 → 2.84; Gemifloxacin: 0 → 1.25; Balofloxacin: 0 → 0.88). The incorporation of the pseudostationary phase significantly enhanced the chiral separation capability. This proposed strategy is characterized by its operational simplicity and low cost, thereby offering a valuable conceptual framework and a highly promising approach for developing chiral separation methods for fluoroquinolone antibiotics. This study represents the first report on employing GA-CQDs as a chiral selective medium to construct a capillary electrophoresis system, which achieved satisfactory enantioselectivity. Furthermore, the chiral recognition mechanism of glucosamine was preliminarily investigated through molecular modeling simulations, with the binding energy providing insights into the separation process.