Study On Preparation And Chromatographic Behaviors Of Organic-Inorgarnic Monolithic Columns Based On "Thiol-Ene" Click Chemistry

As a new generation of chromatographic stationary phase,organic-inorganic hybrid monolithic columns have attracted more and more attention due to its significant advantages such as excellent mechanical strength,high surface area and thermal stability,compared to organic-and silica-based monoliths.So far,a lot of work on organic-inorganic monolithic columns has been reported.However,the subjects that the quest for new kind of functional monomers,the development of novel approach and the expansion of new application fields are always the research hotspots currently.Based on that,we carried out two novel hybrid monolithic columns,and their chromatographic retention mechanisms as well as separation applications were systematically investigated.The thesis mainly includes three chapters,as follows.In chapter one,a general review of the advances of monolithic columns,including the category of monoliths,preparation methods and their applications in diverse fields was introduced.In addition,the research significance and content of this thesis were also briefly presented.In chapter two,a novel 1-(2-dimethylaminoethyl)-5-mercaptotetrazole(MTZ)-silica hybrid monolithic column prepared through "one-pot" process combined with"thiol-ene" click chemistry for capillary liquid chromatography(cLC)was described,in which thiol-end MTZ was mixed with hydrolyzed y-methacryloxypropyltrimeth-oxysilane(?-MAPS)and tetramethyloxysilane(TMOS)for the co-polycondensation and the "thiol-ene" click reaction in one-pot process.The effects of the molar ratio of TMOS/y-MAPS,the amount of MTZ,and the volume of porogen on the morphology,permeability and pore properties of the prepared MTZ-silica hybrid monoliths were examined in detail.A series of test analytes including alkylbenzenes,amides and anilines were used to evaluate the retention behaviors of the optimal MTZ-silica hybrid monolithic column.The results demonstrated that the prepared MTZ-silica hybrid monoliths exhibited hydrophobicity,hydrophilicity as well as ion-exchange interaction.In addition,the MTZ-silica hybrid monolith was further applied to the separation of sulfonamides,nucleobases and a tryptic digest of bovine serum albumin(BSA)and the satisfactory results suggested the potential of MTZ-silica hybrid monolith in the separation of complex samples.In chapter three,a novel polyhedral oligomertic silsesquioxane(POSS)based hybrid monolithic column was prepared via thiol-ene click chemistry.In this approach,polyhedral oligomeric silsesquioxane methacryl substituted(POSS-MA)was used as cross-linker,and 3-mercapto-2-methylpropionyl-proline(CTP)was introduced as functional monomer,using n-propanol and dodecanol as a porogenic system.The effects of the ratio of POSS-MA/CTP,porogenic solvents and click reaction temperature on the morphology,permeability and column performance of the resulting POSS-CTP hybrid monolith were studied in detail.The optimal monolith showed hydrophobic interaction and ion-exchange interaction retention mechanisms,and it was applied to efficiently separate alkylbenzene,polycyclic aromatic hydrocarbon(PAHs),phenols,benzoic acids and intact proteins as well as BSA digest.