Preparation And Chromatographic Application Of POSS-Containing Hybrid Monolithic Column

Organic-silica hybrid monolithic column as stationary phase was widely applied in capillary liquid chromatography（cLC）,because it exhibited great mechanical strength,high separation efficiency and suitable permeability by adjusting porogens.However,there are some deficiencies in the current preparation approaches for hybrid monoliths.To address these deficiencies,new approaches were developed and established to fabricate hybrid monolithic columns with excellent performance through the introduction of polyhedral oligomeric silsesquioxane（POSS）reagents into reaction system in this thesis.1.Three monomers,octakis（3-mercaptopropyl）octasilsesquioxane（POSS-SH）,1,2,4-trivinylcyclohexane and isophytol were employed to fast synthesize an organic-silica hybrid monolithic column via photo-initiated thiol-ene click polymerization.Five alkylbenzenes were employed to evaluate the ability of chromatographic separation of prepared monolithic columns in cLC,and showed the highest column efficiencies of90,200-93,100 N m^-1.Baseline separations of phenolic compounds and anilines were achieved on the hybrid monolithic column.In addition,complex biological samples were separated and analyzed by cLC-MS.One hundred and one unique peptides were positively identified with above 86%high protein sequence coverage for the digest of BSA.And for another more complex digest of extracted proteins from mouse liver,a total of unique1,087 proteins and 2,905 peptides were identified for three paralleled tests.These results demonstrated good potential of the hybrid monolith in analysis of small molecules and complicated biological samples.2.Through introducing POSS-SH synthesized in our lab to the prepolymerization solution containing stearyl acrylate（SA）,1,6-hexanediol ethoxylate diacrylate（HEDA）in the existence of porogenic solvents（tetrahydrofuran,1,4-butanediol and 1-propanol）,a POSS-containing hybrid monolithic column was fabricated via photo-initiated self-polymerization of acrylate and thiol-acrylate polymerization.The resulting poly（SA-co-HEDA-co-POSS）monoliths showed strong hydrophobicity,superior thermal stability and homogeneous microstructure.The highest column efficiencies were79,400-111,000 N m^-1 for alkylbenzenes in reversed-phase liquid chromatography.Subsequently,baseline separations of 9 phenolic compounds,5 anilines and 5 antibiotics were achieved,indicating the monolithic poly（SA-co-HEDA-co-POSS）column had great ability for separation of small molecules.Meanwhile,the tryptic digest of BSA and HeLa were separated and analyzed by cLC-MS.It could be found that 108 unique peptides were positively identified with above 85%high protein sequence coverage for the digest of BSA.A maximum of 1,287 proteins and 5,038 peptides for the digest of mouse liver could be identified for a single test.which further demonstrated good ability of the hybrid monolith in analysis of biological samples.