Ionic Liquids Functionalized Hybrid Monolithic Columns: Preparation And Theirs Performance For Capillary Liquid Chromatography

Capillary liquid chromatography(c-LC) is an important microscale separation and analysis technique with the merit of high speed, high performance, low cost and environmental protection. Chromatographic stationary phase is the core part of c-LC system which determines the column efficiency, separation selectivity and resolution. As one of most promising chromatographic materials, organic-silica hybrid monolithic columns combine the merits of both organic polymer-based monolithic columns and silica-based monolithic columns, such as good mechanical stability and wide pH range tolerance. Obviously, the development of novel and high-efficiency hybrid monolithic columns is crucial significance to meet the demand of microscale separation and analysis.The full text is divided into three chapters.The first chapter: In the first part, the emergence, recent advancements and further applications of hybrid monolithic columns are reviewed. In the second part, the application and recent advancements of new nanomaterials in the monolithic columns are summarized. In the third part, the recent advancements of ionic liquids in the monolithic columns are reviewed.The second chapter: With methacryl substituted polyhedral oligomeric silsesquioxane(POSS-MA) as cross-linker and 1-vinyl-3-octylimidazolium bromide(VOI) as functional monomer, an imidazolium embedded C8 hybrid monolithic column(POSS-VOI) was preperated via “one-pot” approach and further characterized by scanning electron microscopy, Fourier transform infrared spectroscopy(FT-IR), element analysis and so on. With alkylbenzenes as the probes, the retention mechanism of the developed monolithic column was investigated. It exhibited typical reversed-phase chromatographic retention property and the column efficiency reached 124,000 N/m. Furthermore, the developd POSS-VOI monolithic column exhibited higher theoretical plate number and separation pefromance, outperforming the previous reported pentafluorobenzyl imidazolium bromide modified POSS-MA hybrid monolithic column.The third chapter: With POSS-MA and 1-allyl-3-vinylimidazolium bromide(AVI) as precursors, imidazolium bringing POSS-MA periodic micropores monolithic column(POSS-AVI) was fabricated via “one-pot” process. The successful introduction of AVI was demonstrated by FT-IR and elemental analysis. Simultaneously, the morphology, pore size distribution and thermostability of the prepared monolithic column are also investigated, respectively. The developed POSS-AVI monolithic column exhibited reversed-phase chromatographic retention mechanisms and efficient separation of acid, basic and neutral compounds was achieved. Furthermore, compared with the conventional imidazolium modified POSS-MA hybrid monolithic column(POSS-AEI), the proposed POSS-AVI monolithic column exhibited different retention characteristics and higher column efficiency. In addition, high-efficiency separation of hydrophilic nucleosides and nucleic acid base was achived with pure water as the mobile phase. Moreover, the devepoed POSS-AVI monolithic column was further applied for separation of peptides, indicating a good potential.