Preparation of a novel hydrophilic open-tubular capillary column by surface initiated atom transfer radical polymerization and applications in capillary electrochromatography

A novel type of glycopolymer brushes grafted open-tubular capillary column (OTCC) was developed for the polar compound separation. Briefly, the glycerol methacrylate (GMA) polymer brushes were grafted on the inner wall of OTCC by the surface initiated atom transfer radical polymerization (SI-ATRP). Next, glucose was coupled to the side chains of the GMA polymer brushes to obtain the hydrophilic stationary phase (PGMA-N-Glucose). The optimized SI-ATRP reaction conditions were GMA/CuCl/CuCl2/cyclohexanol system grafting at 25 degrees C for 1 h. After the glucose coupling, the column back pressure was about 3,585 kPa. The structure of the glycopolymer brushes on the inner surface of OTCC was characterized by scanning electron microscopy (SEM). The glycopolymer grafting resulted in the formation of three-dimensional wave-like polymer structure on the inner surface of OTCC and largely increased the interior surface area. Therefore, improved column efficiency and loading capacity can be achieved. Under the optimized conditions, the electro osmotic flow (EOF) strength of the glycopolymer brushes grafted OTCC was obviously less than that of the bare column when the pH value of the mobile phase ranging from 3 to 11. Using the glycopolymer brushes grafted OTCC, the baseline separations of polar molecules and proteins were obtained without peak tailing. The future work will focus on the further development of the glycopolymer brushes for the highly polar compound separation, such as glycans and glycoproteins.