Preparation of a magnetic molecularly imprinted polymer by atom-transfer radical polymerization for the extraction of parabens from fruit juices

A silica-based surface magnetic molecularly imprinted polymer for the selective recognition of parabens was prepared using a facile and general method that combined atom-transfer radical polymerization with surface imprinting technique. The prepared magnetic molecularly imprinted polymer was characterized by transmission electron microscopy, Fourier transform infrared spectrometry and physical property measurement. The isothermal adsorption experiment and kinetics adsorption experiment investigated the adsorption property of magnetic molecularly imprinted polymer to template molecule. The four parabens including methylparaben, ethylparaben, propylparaben, and butylparaben were used to assess the rebinding selectivity. An extraction method, which used magnetic molecularly imprinted polymer as adsorbents coupled with high-performance liquid chromatography for the determination of the four parabens in fruit juice samples was developed. Under the optimal conditions, the limits of detections of the four parabens were 0.028, 0.026, 0.021, and 0.026 mg/L, respectively. The precision expressed as relative standard deviation ranging from 2.6 to 8.9% was obtained. In all three fortified levels, recoveries of parabens were in the range of 72.5–89.4%. The proposed method has been applied to different fruit juice samples including orange juice, grape juice, apple juice and peach juice, and satisfactory results were obtained.