[Preparation of hydrophilic, magnetic molecularly imprinted resins of chlorogenic acid and evaluation of its solid-phase extraction performance].

Hydrophilic, magnetic molecularly imprinted resins (MMIRs) were fabricated inside Fe3O4@mSiO2 pores by the one-pot copolycondensation of chlorogenic acid (CGA), resorcinol, melamine, and formaldehyde. The final porous MMIRs with larger numbers of surface recognition sites were obtained by removing mSiO2. The successful preparation of MMIRs was confirmed using transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermo-gravimetric analysis, and water contact angle analysis. The analyses suggest that the MMIRs have excellent hydrophilicity and magnetic solid-phase extraction efficiency. The MMIRs had a good adsorption capacity (50.87 mg/g), fast rate of adsorption (equilibrium was attained at 70 min), and specific recognition for CGA. The MMIRs, in combination with high performance liquid chromatography, were directly used for the selective extraction and determination of CGA in Duzhong brick tea. The limit of detection and recovery were 0.7 mg/L and 93.1%-109.4%, respectively, with relative standard deviations of less than 9.6%. The proposed strategy was extremely promising for the facile, rapid, and selective determination of CGA in real aqueous samples.