Core–shell nano-sized magnetic molecularly imprinted solid phase extractant coupled with HPLC for the selective isolation and determination of 17β-estradiol in a lake water sample

Abstract

In this work, a novel type of core–shell molecularly imprinted magnetic nanoparticles was synthesized and coupled with HPLC for the selective extraction and detection of 17β-estradiol (E2) in lake water samples. The synthesis procedure combined a surface imprinting technique and a facile sol–gel strategy. The morphology, structure, and magnetic properties of the obtained products were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. The adsorption properties of the prepared polymers were investigated by equilibrium rebinding, dynamic adsorption, and selective recognition experiments. The resultant imprinted nanomaterials exhibit not only good dispersibility, stable crystalline structure, and satisfactory super-paramagnetic properties, but also fast kinetics, high capacity (16.87 mg g⁻¹), and favorable selectivity. In addition, the as-synthesized polymers show good reproducibility and could be used for at least six cycles of adsorption–desorption without obvious deterioration. The feasibility of the developed method using the obtained imprinted polymers as a SPE extractant coupled with HPLC for the selective isolation and determination of E2 from real water samples was demonstrated. The recovery of E2 in a lake water sample ranged from 94.2 to 98.3% with the relative standard deviation less than 4.3%. The combined method would greatly improve the sensitivity and expand the practicability of HPLC.