Development of a deep eutectic solvent-based stir-bar hollow-fiber liquid-phase microextraction coupled with HPLC-DAD for the extraction and determination of quinolone antibiotics in egg samples.

Herein, a deep eutectic solvent-based stir-bar hollow-fiber liquid-phase microextraction method has been developed and validated for the extraction of quinolone antibiotics from egg samples. In this method, first, the protein content of the egg is precipitated using a zinc sulfate solution, and then, a hollow fiber is introduced into the obtained liquid phase under stirring. As a result, the analytes are extracted into the acceptor phase (deep eutectic solvent phase) filled inside the porous polypropylene hollow fiber. After that, the hollow fiber is removed, and the deep eutectic solvent phase is withdrawn with a micro-syringe and, after dilution with the mobile phase, injected into a high-performance liquid chromatography-diode array detector for quantitative analysis. The proposed method was validated based on the results obtained. It exhibited low limits of detection (0.37-0.64 ng g-1) and quantification (1.24-2.15 ng g-1), high precision (relative standard deviation ≤5.8%), and acceptable extraction recovery (72-81%). Finally, the proposed analytical process was employed to quantify quinolone antibiotics (fleroxacin, norfloxacin, and ciprofloxacin) in egg samples.