A novel ionic liquid-based monolithic column and its application in the efficient separation of proteins and small molecules by high-performance liquid chromatography

Abstract

A novel skeleton porous polymer-based monolith chromatography column has successfully been prepared using an in situ free radical polymerization technique. A 50 mm × 4.6 mm i.d. stainless steel chromatographic column used dodecanol as porogen and ionic liquid (IL), 1-dodecene (C12) and trimethylol propane triacrylate (TMPTA) as monomers, and ethylene dimethacrylate as crosslinker. The effect of variables such as temperature and porogen solvent content on the porous structure was studied in detail. The polymer-based monolith obtained was characterized by scanning electron microscopy, infrared spectroscopy, mercury intrusion porosimetry, and nitrogen adsorption. The results indicated that the monolithic column had a porous structure, good mechanical stability, high permeability (6.77 × 10⁻¹⁴ m²), and a high specific surface area (155.62 m² g⁻¹). The liquid chromatographic performance of the monolith was evaluated in the separation of lysozyme from egg white and in the separation of a variety of mixtures of small molecules, such as amines and benzene analogues. The column showed good repeatability and reproducibility, and the column-to-column (n = 7) and batch-to-batch (n = 5) reproducibility was 2.85 and 3.15%, respectively.