Preparation of water-compatible magnetic imprinted nanospheres using heptakis (β-cyclodextrin-ionic liquid) as functional monomer for selective recognition of fluoroquinolones in water samples

In this study, a magnetic molecularly imprinted polymer (MMIP) with a well-defined core-shell nanostructure for extracting fluoroquinolones (FQs) using heptakis (beta-cyclodextrin-ionic liquid) (ILs(2)-beta CD), ofloxacin (OFL), triallyl cyanate (TAC), and azobisisobutyronitrile as the functional monomer, template molecule, crosslinking agent, and initiator, respectively, has been directly fabricated in water-containing systems. The morphology, structure, and magnetic properties of the MMIP were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Recombination experiments and competitive adsorption experiments showed that the imprinted material, MMIP, has a good binding capacity (35.85 mg/g), special selectivity, and excellent ability to eliminate matrix interference. Its molecular recognition mechanisms were investigated by the experimental validation with ultra-violet spectroscopy (UV) and proton nuclear magnetic resonance ((HNMR)-H-1), which inferred that hydrophobic and electrostatic interactions are the driving forces for the selective recognition of MMIP. By coupling the MMIP adsorbent with high-performance liquid chromatography, an approach was established to enhance the selective recognition of four structurally similar FQ compounds in real water samples. Several main factors affecting extraction efficiency, such as the sample solution pH value, MMIP dosage, and elution solvent type, were preliminarily optimized. Under the optimal conditions, the method has a good linear relationship (R-2 greater than 0.9990) over a wide range (0.5-1000 mu g/L). The recoveries of the four FQs ranged from 80.11% to 106.71%, and the limits of detection were between 0.43 and 1.83 mu g/L. The results show that this water-compatible molecularly imprinted polymer has broad application prospects for efficient identification and separation as well as enrichment of trace FQs in complex matrices.