State Key Laboratory of Marine Environmental Science, Environmental Science Research Center, Xiamen University, China.
Anal Chim Acta. 2011 Mar 18;689(2):155-9. doi: 10.1016/j.aca.2011.01.020. Epub 2011 Jan 19.
Ion exchange membranes (IEMs) are used in a variety of analytical devices, including suppressors, eluent generators and other components used in ion chromatography. Such membranes are flexible and undergo substantial dimensional changes on hydration. Presently the push to miniaturization continues; a resurgent interest in open tubular ion chromatography requires microscale adaptation of these components. Incorporating IEMs in microscale devices is difficult. Although both macroporous and microporous ion exchange materials have been made for use as chromatographic packing, ion exchange material used as membranes are porous only on a molecular scale. Because such pores have vicinal ion exchange sites, ions of the same charge sign as those of the fixed sites are excluded from the IEMs. Monolithic polymers, including ion exchangers derived therefrom, are presently extensively used. When used in a separation column, such a monolithic structure contains an extensively connected porous network. We show here that by controlling the amount of porogen added during the synthesis of monolithic polymers derived from ethylene dimethacrylate - glycidyl methacrylate, which are converted to an anion exchanger by treatment with trimethylamine, it is possible to obtain rigid ion exchange polymers that behave like IEMs and allow only one charge type of ions to pass through, i.e., are permselective. We demonstrate successful open tubular cation chromatography suppressor performance.
离子交换膜（IEM）用于各种分析设备中，包括抑制器、洗脱液发生器和离子色谱中使用的其他组件。这些膜具有柔韧性，在水合时会发生很大的尺寸变化。目前，微型化的趋势仍在继续；对开管离子色谱的兴趣重新兴起，要求对这些组件进行微尺度适配。将 IEM 整合到微尺度设备中是困难的。尽管已经制备了大孔和微孔离子交换材料用作色谱填充剂，但用作膜的离子交换材料仅在分子尺度上具有多孔性。由于这些孔具有相邻的离子交换位点，与固定位点相同电荷符号的离子被排斥在 IEM 之外。目前，大孔聚合物，包括由此衍生的离子交换剂，被广泛使用。当在分离柱中使用时，这种整体结构包含一个广泛连接的多孔网络。我们在这里表明，通过控制在合成衍生自二甲基丙烯酸乙二醇酯-甲基丙烯酸缩水甘油酯的单体聚合物时添加的致孔剂的量，通过用三甲胺处理将其转化为阴离子交换剂，可以获得刚性的离子交换聚合物，其行为类似于 IEM，并允许仅一种电荷类型的离子通过，即具有选择性。我们展示了成功的开管阳离子色谱抑制器性能。
