含多面体低聚倍半硅氧烷杂化毛细管整体柱的制备及修饰

本文采用自由基聚合法原位制备了两种杂化毛细管整体柱。首先以含有一个甲基丙烯酸基团的多面体低聚倍半硅氧烷(POSS)试剂(Bu-POSS)为单体、以含有多个甲基丙烯酸基团的POSS试剂(POSS-MA)为交联剂在二元致孔剂(正丙醇/聚乙二醇400)和引发剂(偶氮二异丁腈)存在下发生热引发聚合,在毛细管中形成聚(Bu-POSS-co-POSS-MA)杂化整体柱;另外仅以POSS-MA为单体在相同条件下制备聚(POSS-MA)杂化整体柱,并将这两种杂化整体柱应用于小分子的毛细管液相色谱(cLC)分析。结果表明,含POSS杂化整体柱具有制备简单、重现性好以及稳定性高的特点。此外,利用聚(POSS-MA)杂化整体柱表面剩余的甲基丙烯酸基团,可以将功能单体(甲基丙烯酸硬脂酸酯等)化学键合到整体柱上,不但可以提高色谱柱效,而且使其具有不同的选择性。本文所发展的以POSS试剂为原料采用自由基聚合法制备杂化整体柱的方法为新型杂化整体柱的制备提供了一种新思路。

Preparation and modification of polyhedral oligomeric silsesquioxane-containing hybrid monolithic capillary columns

Two kinds of hybrid monolithic capillary columns were prepared via free radical polymerization. First, the hybrid monolithic column was in situ fabricated by using two polyhedral oligomeric silsesquioxanes （POSS）, POSS-methacryl substituted (cage mixture, n=8, 10, 12) (POSS-MA) and POSS-(1-propylmethacrylate)-heptaisobutyl substituted (Bu-POSS), as crosslinker and monomer, respectively, in the presence of porogenic solvents (propanol/PEG400) and initiator (azodisobutyronitrile). Second, the hybrid monolithic column was similarly prepared by using POSS-MA, as sole monomer under the same conditions. The resulting two kinds of hybrid monolithic columns, poly(Bu-POSS-co-POSS-MA) and poly(POSS-MA), were characterized and applied for the separation of alkylbenzenes by capillary liquid chromatography (cLC), showing good mechanical stability and reproducibility. Additionally, the poly(POSS-MA) monolith could be easily modified with other organic monomers, such as stearyl methacrylate (SMA) and benzyl metacrylate (BeMA), with the presence of methacryl groups on the surface of the poly(POSS-MA) monolith. Compared with the raw poly(POSS-MA) monolith, the post-modified poly(POSS-MA) monolith exhibited higher column efficiency and better selectivity. This simple process of using POSS reagents via free radical polymerization is providing a novel way for the preparation of the organic-silica hybrid monolithic columns.