Preparation and application of magnetic molecularly imprinted polymers for the isolation of chelerythrine from Macleaya cordata.

A novel type of magnetic molecularly imprinted polymer was prepared for the selective enrichment and isolation of chelerythrine from Macleaya cordata (Willd) R. Br. The magnetic molecularly imprinted polymers were prepared using functional Fe3 O4 @SiO2 as a magnetic support, chelerythrine as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker. Density functional theory at the B3LYP/6-31G (d, p) level with Gaussian 09 software was applied to calculate the interaction energies of chelerythrine, methacrylic acid and the complexes formed from chelerythrine and methacrylic acid in different ratios. The structural features and morphology of the synthesized polymers were characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry. Adsorption experiments revealed that the magnetic molecularly imprinted polymers possessed rapid kinetics, high selectivity, and a higher binding capacity (7.96 mg/g) to chelerythrine than magnetic molecularly non-imprinted polymers (2.36 mg/g). The adsorption process was in good agreement with the Langmuir adsorption isotherm and pseudo-second-order kinetics models. Furthermore, the magnetic molecularly imprinted polymers were successfully employed as adsorbents for the extraction and enrichment of chelerythrine from Macleaya cordata (Willd) R. Br. The results indicated that the magnetic molecularly imprinted polymers were suitable for the selective adsorption of chelerythrine from complex samples such as natural medical plants.

Magnetic Porous Molecularly Imprinted Polymers Based on Surface Precipitation Polymerization and Mesoporous SiO2 Layer as Sacrificial Support for Efficient and Selective Extraction and Determination of Chlorogenic Acid in Duzhong Brick Tea.

Magnetic porous molecularly imprinted polymers (MPMIPs) for rapid and efficient selective recognition of chlorogenic acid (CGA) were effectively prepared based on surface precipitation polymerization using CGA as template, 4-vinylpyridine (4-VP) as functional monomer, and mesoporous SiO2 (mSiO2) layer as sacrificial support. A computational simulation by evaluation of electronic binding energy is used to optimize the stoichiometric ratio between CGA and 4-VP (1:5), which reduced the duration of laboratory trials. The porous MIP shell and the rid of solid MIPs by magnet gave MPMIPs high binding capacity (42.22 mg/g) and fast kinetic binding (35 min). Adsorption behavior between CGA and MPMIPs followed Langmuir equation and pseudo-first-order reaction kinetics. Furthermore, the obtained MPMIPs as solid phase adsorbents coupled with high performance liquid chromatography (HPLC) were employed for selective extraction and determination of CGA (2.93 ± 0.11 mg/g) in Duzhong brick tea. The recoveries from 91.8% to 104.2%, and the limit of detection (LOD) at 0.8 µg/mL were obtained. The linear range (2.0⁻150.0 µg/mL) was wide with R² > 0.999. Overall, this study provided an efficient approach for fabrication of well-constructed MPMIPs for fast and selective recognition and determination of CGA from complex samples.