Preparation of a porous polymer monolithic column with an ionic liquid as a porogen and its applications for the separation of small molecules in high performance liquid chromatography

A novel porous polymer monolithic column was prepared by in situ free radical polymerization and used as a stationary phase for high performance liquid chromatography (HPLC). In this process, an ionic liquid (IL) was used as a porogen and reaction medium to create pores and enhance the flow-through properties of the polymer monoliths. The effect of IL in the polymerization mixture on the performance of the monoliths was studied in detail. The addition of IL can enhance the resolution and column efficiency compared to the monoliths with alcohol as the porogen. The chromatographic performance of the columns was demonstrated by the separation of various small molecules. The monolith exhibited a typical reversed phase chromatographic behavior with a column efficiency of 12 500 plates per m, which outperformed the commonly used porogen alcohol compounds. The results demonstrated that the IL was a potentially efficient porogen for the preparation of polymer monolithic columns. Moreover, the good mechanical stability, permeability, and reproducibility of column fabrication suggested that the proposed monolith can be expected to be an alternative tool for HPLC separation.