Quercetin adsorption with imprinted polymeric materials

Application of molecular imprinting polymers in separation of active compounds from plants

Molecular imprinting technique is becoming an appealing and prominent strategy to synthesize materials for target recognition and rapid separation. In recent years, it has been applied in separation of active compounds from various plants and has achieved satisfying results. This review aims to make a brief introduction of molecular imprinting polymers and their efficient application in the separation of various active components from plants, including flavonoids, organic acids, alkaloids, phenylpropanoids, anthraquinones, phenolics, terpenes, steroids, and diketones, which will provide some clues to help stimulating research into this fascinating and useful area.

Preparation and Application of Molecularly Imprinted Polymers for Flavonoids: Review and Perspective

The separation and detection of flavonoids from various natural products have attracted increasing attention in the field of natural product research and development. Depending on the high specificity of molecularly imprinted polymers (MIPs), MIPs are proposed as efficient adsorbents for the selective extraction and separation of flavonoids from complex samples. At present, a comprehensive review article to summarize the separation and purification of flavonoids using molecular imprinting, and the employment of MIP-based sensors for the detection of flavonoids is still lacking. Here, we reviewed the general preparation methods of MIPs towards flavonoids, including bulk polymerization, precipitation polymerization, surface imprinting and emulsion polymerization. Additionally, a variety of applications of MIPs towards flavonoids are summarized, such as the different forms of MIP-based solid phase extraction (SPE) for the separation of flavonoids, and the MIP-based sensors for the detection of flavonoids. Finally, we discussed the advantages and disadvantages of the current synthetic methods for preparing MIPs of flavonoids and prospected the approaches for detecting flavonoids in the future. The purpose of this review is to provide helpful suggestions for the novel preparation methods of MIPs for the extraction of flavonoids and emerging applications of MIPs for the detection of flavonoids from natural products and biological samples.

Selective separation of main flavonoids by combinational use of ionic liquid-loaded microcapsules from crude extract of Tartary buckwheat

For selective adsorption of main flavonoids from crude Tartary buckwheat extract (rutin, 0.021 mg/mL; quercetin, 0.030 mg/mL; and kaempferol, 0.011 mg/mL), new ionic liquid-based sorbents were successfully prepared by encapsulating [Bmim]Br and [Bmim]Pro in regular spherical non-magnetic and magnetic microcapsules with polysulfone content of 8%, respectively. After appropriate loading process, the microcapsules were comprehensively characterized by infrared spectroscopy, thermogravimetry analysis and scanning electron microscopy. Then the separation strategy was designed to separate rutin and quercetin from kaempferol by combinational use of two kinds of IL-loaded microcapsules (ILLMs). The effects of solid-liquid ratio of ILLMs and extract, pH, time and adsorption temperature were all investigated. The experimental data fit well with the quasi-second-order kinetics model and Langmuir model. After desorption, target flavonoids were well recovered and the ILLMs showed good stability. As the result, a new IL-based separation technology for main flavonoids from food crop was developed for the first time.

Recent Advances in Molecularly Imprinted Membranes for Sample Treatment and Separation

This review describes the recent advances from the past five years concerning the development and applications of molecularly imprinted membranes (MIMs) in the field of sample treatment and separation processes. After a short introduction, where the importance of these materials is highlighted, a description of key aspects of membrane separation followed by the strategies of preparation of these materials is described. The review continues with several analytical applications of these MIMs for sample preparation as well as for separation purposes covering pharmaceutical, food, and environmental areas. Finally, a discussion focused on possible future directions of these materials in extraction and separation field is also given.