Purpose: In this study, a new magnetic molecularly imprinted polymer was prepared to be used as matrix-dispersive solid phase material to extract a target in food.
Methods: The magnetic molecularly imprinted polymers (MMIPs) were prepared by the sol-gel surface molecularly imprinted technique. Preparing conditions were optimized and the prepared materials were characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, and the adsorption kinetics experiment, equilibrium binding experiment and competitive adsorption experiment had been done. The prepared materials was used as the magnetic matrix-dispersive solid phase extraction adsorbent and coupled with HPLC for determination of diethylstilbestrol residues in milk.
Results: The test results indicated that the saturated adsorption amount of MMIPs for diethylstilbestrol was 522.50 µg g-1 and relative selectivity coefficient of MMIP were 3.35 of hexestrol and 2.98 of dienestrol. The optimized extraction conditions of MMIP were as following: the pH of the extraction solvent was 6.0, eluent was 3 ml methanol and acetic acid (8:2, v/v) and elution time was 3 min. The detection limit (S/N=3) of the developed analytical method could reach 2.0 µg L-1, under the optimum condition, the recoveries of DES at three spiked levels ranged from 90.5% to 103.5% with Relative Standard Deviation in the range of 4.7% to 6.9%.
Significance: The established method promised potential of practical application for selective and sensitive determination of diethylstilbestrol residue in foodstuff samples, which is useful for regulators concerned about foodstuffs.