Improved chiral separation of basic compounds in capillary electrophoresis using beta-cyclodextrin and tetraalkylammonium reagents.
Improved chiral separation of basic compounds in capillary electrophoresis using beta-cyclodextrin and tetraalkylammonium reagents.
复制标题
使用 β-环糊精和四烷基铵试剂改进毛细管电泳中碱性化合物的手性分离。
DOI：
10.1021/ac00071a003
复制
发表时间：
1993
影响因子：
7.4
通讯作者：
Khaledi,MG
中科院分区：
文献类型：
--
作者：
Quang,C;Khaledi,MG
本文介绍了环糊精包合物在毛细管电泳手性分离中的应用。四烷基铵试剂，包括长链阳离子表面活性剂和短链烷基铵氢氧化物，检查用于控制电渗流，以提高阳离子对映体的分辨率。在这方面，短链四烷基铵阳离子（如四丁基铵和四甲基铵）更有效。首先，短链四烷基铵阳离子可以以比长链阳离子表面活性剂高得多的浓度使用，长链阳离子表面活性剂在几毫摩尔浓度范围内形成胶束。结果，短链试剂提供了更好的毛细血管壁覆盖，这导致在酸性pH 2.5下电渗流方向的减少或逆转。第二，短链四烷基铵阳离子的疏水性相对较低，与长链阳离子表面活性剂相比，不太可能占据/8-CD的疏水空腔，从而使分析物更容易获得对映选择性相互作用位点。这些四烷基铵阳离子的存在在许多手性分离中是必不可少的，据报道，这些手性分离不能通过使用仅含有8-CD作为手性选择剂的缓冲电解质来实现。此外，还讨论了8-CD对一组立体异构体的手性识别机理。
Approaches to improve resolution in chiral sep-aration of several basic pharmaceutical com-pounds by capillary electrophoresis (CE) via a cyclodextrin (CD) inclusion complexation are described. Tetraalkylammonium reagents, including long-chain cationic surfactants and shortchain alkylammonium hydroxides, are examined for controlling the electroosmotic flow in order to improve resolution of the cationic enantiomers. In this regard, short-chain tetraalkylammonium cations (such as tetrabutylammonium and tet-ramethylammonium) are more effective. First, the short-chain tetraalkylammonium cations can be used at much higher concentrations than the long-chain cationic surfactants, which form micelles in the few millimolar concentration range. As a result, a better capillary wall coverage is provided with the short-chain reagents, which leads to reduction or reversal of the direction of the electroosmotic flow at the acidic pH 2.5. Second, the short-chain tetraalkylammonium cations are relatively less hydrophobic and less likely to occupy the hydrophobic cavity of/8-CD than the long-chain cationic surfactants, leaving the enan-tioselective interaction sites more available for the analytes. The presence of these tetraalkylammonium cations was essential in many chiral sepa-rations that were reportedly not achieved by using the buffer electrolytes containing only the 8-CD as a chiral selector. In addition, a mechanism of chiral recognition by 8-CD for a group of stere-oisomers is discussed.