Synthesis of iron oxide magnetic nanoparticles modified with silica based molecularly imprinted polymer for the extraction and preconcentration of phenazopyridine

When modified with a specific functional polymer, for example, the molecularly imprinted polymer (MIP), these magnetic nanoparticles coated MIP could be used to separate and concentrate chemicals more conveniently with the help of an external magnetic field. In this study, we focused on the development of a new methodology for preparing MNPs attached functional moieties of specific recognition with tailor-made properties through molecular imprinting technique. Fe3O4 MNPs were synthesized by modifying the procedure as reported by Kanget et al. [1]. For the synthesis of the MIP@Fe3O4 composite, first, 20 mL of cyclohexane, 3.6 mL of Triton X-100, 4.4 mL of butanol and 1.0 mL of distilled water were stirred for 5 min. The Fe3O4 (0.1 g) was added to the above solution, then stirring 30 min in room temperature. Second, 200 μL of TEOS and 100 μL of NH3·H2O were added to the above reaction solution. The mixture was stirred for 10 h so that the Fe3O4 was successfully encapsulated with silicon. Third, 0.1 g of phenazopyridine (dispersed in 20 mL of ethanol) and 250 μL of APTES were added to the system with stirring for 1 h. Afterwards, 500 μL of TEOS and 1 mL of NH3· H2O were added in the microemulsion and stirred for 12 h. The silica coating MNPs Fe3O4@SiO2 reacted with phenazopyridine to produce silica surface functionalized with MIPs. The prepared adsorbent was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FT-IR). In conclusion, we explored synthesis of phenazopyridine-imprinted polymer coated Fe3O4 magnetic nanoparticles that exhibit a much higher specific recognition and saturation magnetization.