Abstract: Capillary monolithic columns (75 μm i.d.) were prepared by the copolymerization of lauryl methacrylate as the basic monomer, ethylene dimethacrylate as the cross-linking agent and 1-dodecyl alcohol, 1,4-butanediol and dimethyl sulfoxide as the porogenic mixture. The synthetic stationary phases had better mechanical properties and chemical stabilities. A series of characterization and evaluations were performed on the capillary monolithic columns including the scanning electron microscope (SEM) images, the influences of pressure and the effects on the separation of peptide mixtures by changing the proportions of the porogen solution and cross-linking agent. The final prescription contained 15% (w/w) monomer, 15% (w/w) cross-linking agent, and 70% (w/w) porogenic agent. Then the solution was heated at 70 ℃ for 24 h. The test of relationship between column length and back pressure showed that the capillary monolithic columns prepared have superior permeability, so a longer column can be used to improve the effects of separation. The prepared capillary monolithic columns are fitted on the nano-scale high performance liquid chromatography for the separation of tryptic digests of bovine serum albumin (BSA) and human plasma samples, and better results have been obtained.

Key words: nano-scale high performance liquid chromatography (nano-HPLC), polypeptide separation , capillary monolithic column