Department of Chemistry, University of Marburg, Hans-Meerwein-Str., D-35032 Marburg, Germany.
J Chromatogr A. 2011 Feb 25;1218(8):1185-94. doi: 10.1016/j.chroma.2010.12.101. Epub 2011 Jan 4.
A set of five new sulfobetaine exchangers with inner quaternary amines and outer sulfonic acids have been prepared. A series of zwitterionic precursors was attached to highly porous divinylbenzene polymer using a grafting reaction, which allows a flexible adjustment of the degree of functionalisation. The resulting materials have identical spacers to the polymeric backbone and differ only in chain length between the charged functional groups. Capacities of the stationary phases were analysed by two different methods based on elemental analysis and the results obtained were found to correlate. The application of combustion elemental analysis proved an identical molar content of sulfur and nitrogen. The distance between the charged functional groups is varied from one to five methylene groups for a better understanding of the retention behaviour of inorganic anions on zwitterionic stationary phases. Inorganic anions were separated using sodium acetate eluents with varying ionic strength and pH and the behaviour of all columns has been compared to each other and to ZIC-HILIC and ZIC-pHILIC columns from Merck SeQuant. The exchangers with two and five methylene groups between the charges showed the highest retention factors. Polarity and accessibility of the anion exchange sites are dependent on the distance between the charged groups and the flexibility of the chains. These properties have a strong influence on anion separations. The exchanger with two methylene groups between the charged functional groups showed the biggest difference as compared to the commercially available ZIC-HILIC and ZIC-pHILIC exchangers.
已经制备了一组带有内季铵盐和外磺酸基的五种新型磺丁基甜菜碱交换剂。一系列两性离子前体通过接枝反应连接到高多孔的二乙烯基苯聚合物上，这允许灵活调整官能化程度。所得材料与聚合物主链具有相同的间隔基，仅在带电官能团之间的链长上有所不同。通过基于元素分析的两种不同方法分析固定相的容量，并且获得的结果相关。燃烧元素分析的应用证明了硫和氮的摩尔含量相同。为了更好地理解两性离子固定相上无机阴离子的保留行为，带电官能团之间的距离从一个到五个亚甲基不等。使用具有不同离子强度和 pH 的乙酸钠洗脱剂分离无机阴离子，并将所有柱的行为彼此进行比较，并与来自 Merck SeQuant 的 ZIC-HILIC 和 ZIC-pHILIC 柱进行比较。在电荷之间具有两个和五个亚甲基的交换剂显示出最高的保留因子。阴离子交换位点的极性和可及性取决于带电基团之间的距离和链的灵活性。这些性质对阴离子分离有很大的影响。与市售的 ZIC-HILIC 和 ZIC-pHILIC 交换剂相比，在电荷之间具有两个亚甲基的交换剂显示出最大的差异。
