Fabrication and characterization of a composite monolithic guard column for the analysis of active components contained in medicinal plants using high-performance liquid chromatography.

A composite monolithic column was prepared via polymerization in a 10-mm-long tube, using a porphyrin-based covalent organic framework (COF) as the co-monomer. The fabricated monolith exhibit good permeability, relatively uniform porous structure and high specific surface area, which was used as a guard column prior to an analytical column for the analysis of active components in medicinal plants with HPLC. Ten kinds of medicinal plants were used as the samples, in which sixteen target components were separated and analyzed, as well as the fingerprints of herb and herb couple. Compared to a generally used commercial VAST silica gel-C18 guard column, the homemade guard column shows good permeability with fast mass transfer, short analytical time and strong reusability with more than 100 injections, thus indicating the present monolith is an outstanding guard column prior to the C18 analytical column for the analysis of multiple active components in various medicinal plants.