Controlling the surface chemistry and chromatography properties of methyacrylate-ester-based monolithic capillary colums via photografting
Controlling the surface chemistry and chromatography properties of methyacrylate-ester-based monolithic capillary colums via photografting
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DOI：
10.1002/jssc.200600316
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发表时间：
2007-02-01
影响因子：
3.1
通讯作者：
Kok, Wim Th.
中科院分区：
文献类型：
--
作者：
Eeltink, Sebastiaan;Hilder, Emily F.;Kok, Wim Th.
研究了紫外光引发聚合普通色谱柱，然后通过光接枝对其孔表面进行功能化处理，制备用于CEC模式分离的整体毛细管柱。第一步，通过控制聚合混合物中致孔剂1-癸醇和环己醇的比例、辐射时间和紫外光强度，制备了具有优化多孔性能的通用聚甲基丙烯酸丁酯-二甲基丙烯酸乙二醇酯单体。然后将可电离单体[2-(甲基丙烯酰氧基)乙基]三甲基氯化铵或2-丙烯酰胺基-2-甲基-1-丙磺酸光接枝到整体基质上，使我们能够控制CEC中EOF的方向。采用不同的策略来控制接枝密度，从而控制EOF的大小。为了控制疏水性能，我们测试了两种方法：(I)可电离单体和疏水单体的混合物共接枝和(Ii)可电离单体和疏水单体的顺序接枝。同种移植导致相似的保留，但更高的EOF。采用顺序接枝，由于屏蔽了可电离部分，保留率提高了50%以上，EOF略有下降。
Preparation of monolithic capillary columns for separations in the CEC mode using UV-initiated polymerization of the plain monolith followed by functionalization of its pore surface by photografting has been studied. The first step enabled the preparation of generic poly(butyl methacrylate-co-ethylene dimethacrylate) monoliths with optimized porous properties, controlled by the percentages of porogens 1-decanol and cyclohexanol in the polymerization mixture, irradiation time, and UV light intensity. Ionizable monomers [2-(methacryloyloxy)ethyl]trimethylammonium chloride or 2-acryloamido-2-methyl-1-propanesulfonic acid were then photografted onto the monolithic matrix, allowing us to control the direction of the EOF in CEC. Different strategies were applied to control the grafting density and, thereby, the magnitude of the EOF. To control the hydrophobic properties, two approaches were tested: (i) cografting of a mixture of the ionizable and hydrophobic monomers and (ii) sequential grafting of the ionizable and hydrophobic monomers. Cografting resulted in similar retention but higher EOF. With sequential grafting, more than 50% increase in retention factors was obtained and a slight decrease in EOF was observed due to shielding of the ionizable moieties.