Facile fabrication of surface molecularly imprinted magnetic polydopamine for selective adsorption of fluoroquinolone from aqueous solutions

Abstract

To address problems such as environmental accumulation, improved methods are required for the detection and analysis of fluoroquinolones. Herein, we prepared a surface molecularly imprinted polymer (MIP) based on dopamine-coated magnetic nanoparticles. The performance of this MIP as a novel adsorbent for fluoroquinolones was analyzed using high-performance liquid chromatography. Furthermore, the morphology and physicochemical properties of the prepared material were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, Brunauer–Emmett–Teller surface area analysis, and vibrating sample magnetometry. The synthesized molecules consisted of a core–shell constitution with a Fe3O4 nucleus and a polydopamine enclosure, the surface of which was imprinted using gatifloxacin as a template molecule. The obtained polymers had a high specific surface area, good superparamagnetism, and excellent selectivity of the target molecules. Under optimal adsorption conditions, the ultimate loading capacity of gatifloxacin on the MIP was 51.9 mg/g, with an equilibrium adsorption time of 30 min and an imprinting factor of 2.24. After six cycles, the adsorption capacity of this adsorbent did not decrease significantly. For the analytical characteristics of the method, we inserted the application part of the sample in the local river water. Through the spiked recovery of the three FQs aqueous solutions, it was found that their spiked recovery, LOD, and LOQ were 84.1–91.9%, 6.4–9.9 ng mL−1, and 17.8–34.5 ng mL−1, respectively. Owing to its adsorption selectivity and recyclability, this magnetic MIP is a promising adsorbent for sample separation and pretreatment applications.