Preparation And Application Of Novel Capillary Columns

Capillary column is the core of capillary liquid chromatography(cLC)separation,which is the foundation for the development of various separation modes.To circumvent some problems and shortcomings in the preparation of capillary column,several novel approaches were established and developed in the thesis.(1)As surface modification of hybrid monoliths was always carried out using the remaining functional groups,we prepared two kinds of hybrid monoliths with methacrylate epoxy cyclosiloxane(epoxy-MA)as functional monomer,which contained three epoxy moieties and one methacrylate group.One column was in situ fabricated by ring-opening polymerization of epoxy-MA with 1,10-diaminodecane(DAD),and the other was prepared by free radical polymerization of epoxy-MA with ethylene dimethacrylate(EDMA).Depending on the remaining epoxy or methacrylate groups on the surface of two pristine monoliths,epoxy-MA-EDMA monolith could be modified with 1-octadecylamine(ODA)via ring-opening reaction,while epoxy-MA-DAD monolith could be modified with stearyl methacrylate(SMA)via free radical reaction.Chromatographic performances of the resulting columns were evaluated by cLC separation of alkylbenzenes.It was found that epoxy-MA-DAD monolith possessed higher column efficiencies(25,000-34,000 N/m)than epoxy-MA-EDMA monolith(12,000-13,000 N/m).In addition,the chromatographic efficiencies on SMA-modified epoxy-MA-DAD monolith(42,000-54,000 N/m)were remarkably improved comparing with those on pristine epoxy-MA-DAD monolith,while they were not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith comparing with those on pristine epoxy-MA-EDMA monolith.Besides,two kinds of hybrid monoliths were also applied for cLC separation of phenols and basic compounds.(2)Since organic-inorganic hybrid monolith prepared by thermally-initiated free radical polymerization possessed poor separation efficiency,we synthesized hybrid monolith by photo-initiated polymerization of methacrylate epoxy cyclosiloxane(epoxy-MA)with polyhedral oligomeric silsesquioxane methacrylate(POSS-MA).Chromatographic properties of photo-and thermally-polymerized epoxy-MA-POSS monoliths were evaluated,showing that hybrid monoliths fabricated by photochemical initiation possess higher column efficiencies(97,000-98,400 N/m)than those synthesized by thermal polymerization(41,100-48,000 N/m)in cLC.The higher efficiency of photo-initiated hybrid monoliths was closely related to lower eddy dispersion(A-term)and mass transfer resistance(C-term).(3)As poly(pentaerythritol diacrylate monostearate,PEDAS)monolith was poor in separation efficiency,we fabricated a polymer monolith by thiol-acrylate polymerization of PEDAS with trimethylolpropane tris(3-mercaptopropionate)(TPTM).The resulting poly(PEDAS-co-TPTM)monolith possessed higer separation efficiency(15.7-17.7 ?m)than poly(PEDAS)monolith(19.1-37.9 ?m).In addition,66 unique peptides were positively identified when tryptic digest of four proteins was separated by cLC-MS/MS,demonstrating its potential in proteomic analysis.(4)As the PLOT phase was apt to 'bleed' from the stationary phase,plugging columns or even damaging detectors due to the unstable coating,we fabricated an organic-inorganic hybrid PLOT column by in situ ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxanes(POSS-epoxy)with 4-aminophenyl disulfide(APDS)using ethanol/H2O(13:1,v/v)as the porogens.The resulting column was evaluated by cLC-MS/MS analysis of mouse liver tryptic digest.As a result,4235 unique peptides and 1234 proteins were totally identified on the PLOT column,demonstrating its potential in proteomic analysis.