Separation of Polysaccharides by SEC Utilizing Deep Eutectic Solvent Modified Mesoporous Siliceous Materials

Four new green deep eutectic solvents (DESs) based on betaine were prepared. In addition, one conventional (i.e., not synthesized using DESs) and four betaine-based mesoporous materials were generated by hydrothermal synthesis. All of the mesoporous materials had spherical shapes. The proposed mesoporous materials were characterized by scanning electron microscopy, nitrogen sorption analysis, and thermogravimetric analysis, and were used as sorbents in high-performance size-exclusion chromatography to separate polysaccharides. Six dextrans with different molecular weights (5, 25, 50, 270, 670, and 1100 kDa) were then applied as target compounds for separation. The DES-based mesoporous materials provided better separation of the dextrans than the conventional mesoporous materials, and the betaine–urea-based column was found to give the best results, especially for dextrans <270 kDa in molecular weight. These results indicate that the presence of a betaine-based DES during mesoporous material synthesis had a positive influence on the size-exclusion separation capabilities of the resulting material.