Preparation Of Magnetic Molecularly Imprinted Polymers For Diethylstilbestrol And Its Application In Milk Detection

This study took diethylstilbestrol (DES) as template molecule, adoptingrespectively the bulk polymerization and sol-gel method to prepare the two types ofmagnetic molecularly imprinted polymers (MMIP). The two kinds of materials wereemployed as solid phase extraction adsorbent. A method of the determination ofdiethylstilbestrol residues in milk was established by magnetic solid phase extractioncoupled with high performance liquid chromatography (HPLC).First, the magnetic molecularly imprinted polymer was synthesized using Fe3O4particles as magnetic microcarrier, DES as template molecule, methacrylic acid (MAA)as the functional monomer,3-(Trimethoxysilyl)propyl methacrylate (γ-MAPS) as thecrosslinking agent, and azodiisobutyronitrile (AIBN) as the initiator through bulkpolymerization. The preparative material possessed superparamagnetism and selectiveadsorption, and used as magnetic solid phase extraction adsorbent. A method of thedetermination of diethylstilbestrol residues in milk was established by magnetic solidphase extraction coupled with HPLC. The results indicated that the detection limit(S/N=3) of the developed method could reach2.0μg/L under the optimum condition.The recoveries of DES from the milk samples at three spiked levels ranged from88.3%to97.6%with RSD in the range of5.0%～7.9%.Second, the magnetic molecularly imprinted polymer was synthesized using Fe3O4particles as magnetic microcarrier, diethylstilbestrol as template molecule,3-aminopropyltriethoxysilane (APTES）as the functional monomer, tetraethoxysilane(TEOS) as the crosslinking agent, and0.1mol/L acetic acid as the initiator throughsol-gel method. The preparative material possessed superparamagnetism and selectiveadsorption, and used as magnetic solid phase extraction adsorbent. A method of thedetermination of diethylstilbestrol residues in milk was established by magnetic solidphase extraction coupled with HPLC. The results indicated that the detection limit(S/N=3) of the developed method could reach2.0μg/L under the optimum condition.The recoveries of DES from the milk samples at three spiked levels ranged from90.5%to103.5%with RSD in the range of4.7%～6.9%.In conclusion, in this dissertation two different methods were employed to preparethe DES magnetic molecularly imprinted polymer whereby the DES could be enrichedefficiently. It was promising for the prepared MMIPs to application in the pretreatment for the detection of DES residue in milk product. Last, two kinds of magneticmolecularly imprinted polymers were compared in order to find the differences betweenthem.