Novel molecular imprinted polymers over magnetic mesoporous silica microspheres for selective and efficient determination of protocatechuic acid in Syzygium aromaticum.

Abstract Improving sites accessibility can increase the binding efficiency of molecular imprinted polymers (MIPs). In this work, we firstly synthesized MIPs over magnetic mesoporous silica microspheres (Fe 3 O 4 @mSiO 2 @MIPs) for the selective recognition of protocatechuic acid (PCA). The resulting Fe 3 O 4 @mSiO 2 @MIPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT-IR), thermo-gravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and vibration sample magnetometer (VSM), and evaluated by adsorption isotherms/kinetics and competitive adsorption. The maximum adsorption capacity of PCA on Fe 3 O 4 @mSiO 2 @MIPs was 17.2 mg/g (2.3 times that on Fe 3 O 4 @SiO 2 @MIPs). In addition, Fe 3 O 4 @mSiO 2 @MIPs showed a short equilibrium time (140 min), rapid magnetic separation (5 s) and high stability (retained 94.4% after six cycles). Subsequently, Fe 3 O 4 @mSiO 2 @MIPs were successfully applied for the selective and efficient determination of PCA (29.3 μg/g) from Syzygium aromaticum . Conclusively, we combined three advantages into Fe 3 O 4 @mSiO 2 @MIPs, namely, Fe 3 O 4 core for quick separation, mSiO 2 layer for enough accessible sites, and surface imprinting MIPs for fast binding and excellent selectivity, to extract PCA from complex systems.