Recent advances in the application of nanomaterials for separation and enrichments of small molecule active ingredients of traditional Chinese medicine

In this review, we focused on the nanomaterials and applications used to separate and enrich the small molecule active components of traditional Chinese medicine (TCM) in the past 5 years (2018–2023), including magnetic molecularly imprinted polymers (MMIPs), magnetic surface functionalized dummy template molecularly imprinted polymers (magnetic surface functionalized DMIPs), borate functionalized magnetic solids (BFMS), metal–organic framework materials (MOFs) and molecularly imprinted mesoporous silica (MIP-MS). This review provides a reference for further innovation and development of separation and enrichment technology of pharmacodynamic substances in TCM. Among them, MMIPs have been applied more in the active ingredients of small molecules in TCM, mainly for flavonoids, terpenoids, alkaloids and organic acids, and this technology is more advanced. Magnetic surface functionalized DMIPs have high specificity and selectivity for target analytes, which can shorten the separation and enrichment time and increase the yield. The use of this manomaterial for the separation and enrichment of some natural active ingredients can effectively make up for the shortcomings of traditional MIPs. In addition, studies in the past 5 years have also shown some progress in the separation and enrichment of small molecule components by BFMS, MOFs and MIP-MS. For example, BFMS can be used to separate glycosides, MOFs to separate flavonoids, and MIP-MS to separate organic acids. However, the application of these materials for small molecules of TCM is still insufficient, including fewer application examples in the field of chromatography, and some of the materials have never even been utilized. Meanwhile, most of them have only been initially applied to solid-phase extraction in the pre-treatment of chromatography. Therefore, we believe that we can try to apply these nanomaterials more to the separation and enrichment of the active ingredients of small molecules in TCM afterwards, thus advancing the development of chromatography.