Preparation And Application Of POSS-based Hybrid Silica Hypercrosslinked Monolithic Columns

Polyhedral oligomeric silsesquioxane(POSS)-based organic-silica hybrid monolithic columns possess of stable structure and good solvent resistance,and have become an important type of organic-silica hybrid monoliths.In this paper,based on the thermal initiation polymerization,the preparation of organic-silica hybrid monolithic column with benzyl chloride was carried out,and then POSS-based polystyrene hypercrosslinked monolithic column via Friedel-Crafts reaction was frabricated.The preparation of organic-silica hybrid hypercrosslinked monolithic columns were studied,and the evalucation of chromatography performance and its application of POSS-based hypercrosslinked monolith in electrochromatography have been obtained.main points are listed as follows:In chapter l,literature review about the classification and main general situation of capillary monolithic column are expounded.The research progress and application trend of organic hypercrosslinked monolithic column are introduced.On this basis,the research direction and experimental scheme of this paper is put forward.In chapter 2,based on the method of in-situ polymerization,by using vinyl chloride(VBC)functional monomer,polyacrylate oligomer silsesquioxane(POSS-MA)as crosslinker,the organic-silica hybrid monolithic column with benzyl chloride functional group was prepared.Various parapmeters including polymer composition,morphology,mechanical stability,swelling and retention mechanism of the POSS-based monolith were investigated.The structure of the obtained poly(VBC-co-POSS-MA)monolithic column is homogeneous,and possess of obvious merits such as good stability,low swelling coefficient and high hydrophobic effect.It has always shown the reverse retention effect in the mobile phase with different acetonitrile ratio,and have a good retention and enrichment effect for alkylbenzene and polycyclic aromatic hydrocarbons.In chapter 3,the POSS-based organic-silica hybrid hypercrosslinked monolithic column was prepared based on Friedel-Crafts reaction of poly(VBC-co-POSS-MA)column.The morphology,swelling,specific surface area and retention mechanism of hypercrosslinked monolithic column were investigated.The stability of the prepared hypercrosslinked monolithic column is good,and the specific surface area and swelling resistance of the organic reagent are greatly improved.The hydrophobic alkylbenzene and polycyclic aromatic hydrocarbons have a good retention effect on the monolithic column,separation efficiency and column enrichment coefficient were higher than that of non-hypercrosslinked monolithic column.Four polycyclic aromatic hydrocarbons(PAHs)were concentrated and continuously separated in the electrochromatography with the detection limit at ppb level.The detection sensitivity is nearly three orders of magnitude higher than conventional injections.In chapter 4,by using POSS-based organic-silica hybrid hypercrosslinked monolithic column,the enrichment analysis of artificial musks with pressurized capillary electrochromatography was explored.Using cashmeran and tonalide as the representative,the retention and separation behavior of artificial musks on the hypercrosslinked monolithic column in capillary electrochromatography was studied.The parameters such as sample solvent,injection volume,separation voltage and injection time were investigated and optimized.Under the optimal conditions,the artificial musks were well enriched and continuously separated in the electrochromatography with a limit of quantification of 5 ppb.Compared with the non-enriched capillary electrochromatography,a good result with the analytical sensitivity was improved by more than 1000 times.