Thermosensitive molecularly imprinted polymer coupled with HPLC for selective enrichment and determination of matrine in traditional Chinese medicine.

In this study, a temperature-sensitive molecularly imprinted polymer was prepared by using the bifunctional monomer with the critical phase transition characteristics. Infrared spectrometry, scanning electron microscopy, and specific surface area testing were used to characterize the polymers. Then, the recognizing properties of the polymers were studied. Based on the prepared smart polymers, an SPE-HPLC analytical method for the determination of quinolizidine alkaloids in the extracts of Sophora flavescens was established and verified. Finally, the smart polymers were applied to the enrichment of quinolizidine alkaloids in plant extracts. By changing the temperature and solvents of the solid phase extraction conditions, the extraction process can increase the concentration of quinolizidine alkaloids by 4.3 to 5.2 folds. The extraction process has mild conditions and less time consumption, avoiding the use of a large number of toxic reagents, which indicate that the extraction process are more efficient and environmentally friendly.