Abstract
In this study, novel open-tubular nano-columns with highly hydrophobic stationary phase were prepared via the surface graft polymerization of polyhedral oligomeric silsesquioxane-methacrylate and 2-vinylnaphthalene in a narrow capillary (i.e., 20 mu m i.d.. In this preparation, polyhedral oligomeric silsesquioxane-methacrylate was used as a reactive and stable monomer while 2-vinylnaphthalene imparts hydrophobic character for the stationary phase. Toluene and dodecanol were used as the porogenic solvent. Scanning electron microscope images of the columns showed that polyhedral oligomeric silsesquioxane and 2-vinylnaphthalene were bound to the surface of the capillary. The chromatographic characterization of the open-tubular columns was performed using homologous alkylbenzenes, including toluene, ethylbenzene, propylbenzene, and butylbenzene. The satisfactory separation of alkylbenzenes could be obtained using the final open-tubular column with 17.1% of 2- vinylnaphthalene. Theoretical plates number up to 34000 plates/m in the isocratic mode for ethylbenzene were achieved. The open-tubular column with various lengths was used for the separation of intact proteins in nano-liquid chromatography, allowing a notable change in the retention time of each intact protein, including ribonuclease A, Lysozyme, and alpha-Chymotryp A. The final open-tubular column was then applied to the peptide separation of trypsin-digested cytochrome C. It was shown that the open-tubular column yielded a high-resolution analysis of peptides, providing a high peak capacity of up to 1000.