title: Preparation of doxycycline-imprinted magnetic microspheres by inverse-emulsion suspension polymerization for magnetic dispersion extraction of tetracyclines from milk samples.
abstract: A magnetic dispersion extraction method was developed based on a molecularly imprinted magnetic microsphere (MIMM) for the selective clean-up and enrichment of tetracycline antibiotics from milk samples. The MIMMs were prepared by inverse-emulsion suspension polymerization, using doxycycline, trimethylolpropane trimethacrylate, acrylamide, methacrylic acid, and surface-modified Fe3 O4 as a template molecule, crosslinker, functional monomer, and magnetic component, respectively. Synthesis and extraction conditions were optimized for obtaining excellent affinity and high selectivity. The magnetism, covering amount, and selectivity of the magnetic microspheres were characterized by a vibrating sample magnetometer, thermogravimetric analysis, and a competitive recognition experiment. The MIMMs were applied to separate tetracycline antibiotics from milk samples by magnetic dispersion extraction, and an enrichment factor of 9.28 and a good sample clean-up were obtained. The average recoveries of four tetracycline antibiotics were obtained in the range of 74.5-93.8% with a precision of 1.2-5.2%. The LODs and LOQs of the proposed method were in the range of 7.4-19.4 and 24.7-64.7 μg/kg, respectively. The results indicated that magnetic dispersion extraction using MIMMs is a powerful tool for food-sample pretreatment with high selectivity and a simplified procedure.
authors.affiliation: Key Laboratory of Analytical Science and Technology, College of Chemistry and Environmental Science, Hebei University, Hebei Province, Baoding, PR China.
authors.forename: Yun-Kai
authors.initials: YK
authors.lastname: Lv
authors.forename: Chen-Xi
authors.initials: CX
authors.lastname: Zhao
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.forename: Yan-Dong
authors.initials: YD
authors.lastname: He
authors.forename: Zhong-Rui
authors.initials: ZR
authors.lastname: Yang
authors.forename: Han-Wen
authors.initials: HW
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification*; D002417:Cattle; D004318:Doxycycline / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D005506:Food Contamination / Q000032:analysis*; D008280:Magnetics; D008863:Microspheres; D008892:Milk / Q000737:chemistry*; D054802:Molecular Imprinting; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D013754:Tetracyclines / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D004655:Emulsions; D011108:Polymers; D013754:Tetracyclines; D004318:Doxycycline
keywords: Magnetic dispersion extraction; Magnetic microspheres; Milk; Molecularly imprinted polymers; Tetracycline antibiotics