Synthesis of novel oxytetracycline-molecularly imprinted polymer using a semi-covalent chemical imprinting approach for magnetic dispersive solid phase extraction of tetracyclines in water and milk samples

In the present study, a highly efficient analytical method based on preconcentration of tetracyclines (TCs) in water and milk samples using a magnetic molecularly imprinted polymer (Fe3O4/SiO2/MIP) synthesized by means of a novel semi-covalent synthesis for TCs and determination by HPLC-DAD was proposed. Fe3O4/SiO2/MIP showed specific superficial area of 216.0 m2/g, superior to Fe3O4/SiO2/NIP (non-imprinted material) (103.6 m2/g). Using the Fe3O4/SiO2/MIP, the magnetic dispersive solid phase extraction (MDSPE) for four TCs (chlortetracycline, doxycycline, oxytetracycline, and tetracycline) was based on the preconcentration of 40.0 mL of sample (pH 4.0) vortex-assisted with 10 mg of Fe3O4/SiO2/MIP during 60 s. The method presented a limit of detection (LOD) in the range 0.26-0.60 µg/L, and preconcentration factor in the range 52.3-87.4-fold for the TCs. The method was applied to determine TCs in samples of lake water and cow milk with recovery results ranging from 96.0 to 102.0 %.