Chemical selectivity in micellar electrokinetic chromatography: characterization of solute-micelle interactions for classification of surfactants.
Chemical selectivity in micellar electrokinetic chromatography: characterization of solute-micelle interactions for classification of surfactants.
复制标题
胶束电动色谱中的化学选择性：溶质-胶束相互作用的表征，用于表面活性剂的分类。
DOI：
10.1021/ac00099a004
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发表时间：
1995
影响因子：
7.4
通讯作者：
Khaledi,MG
中科院分区：
文献类型：
--
作者：
Yang,S;Khaledi,MG
通过线性溶剂化能关系（LSER）和官能团选择性研究了表面活性剂种类对胶束电动色谱（MEKC）迁移行为和化学选择性的影响。在LSER建模中，溶质的容量因子与其结构描述符（例如大小、偶极性和氢键能力）相关。使用的LSER方法，溶质与不同类型的表面活性剂聚集体的相互作用的性质的有用信息，可以得到因为在MEKC容量因子是直接相关的溶质之间的分配的散装水性溶剂和胶束。对60种不带电荷的非氢键（NHB）、氢键受体（HBA）碱和氢键供体（HBD）酸的芳香族化合物在MEKC中的迁移行为的不同LSER模型进行了相关性研究。在十二烷基硫酸钠（SDS）和胆酸钠（SC）的两种阴离子烃胶束体系中，保留主要受分子大小及其氢键接受碱度的影响。它们的偶极性/极化性和提供氢键的酸性起次要作用。在SDS和SC体系中，溶质的容量因子随分子大小的增加而增加，随氢键受体碱基的增加而减小。这些结果与其他系统中观察到的结果相似，其中疏水相互作用起主要作用，例如，在1-辛醇-水溶剂系统中的溶质分布或在反相LC中的保留。在MEKC与阴离子氟碳表面活性剂，全氟辛烷磺酸锂（LiPFOS），但是，大小和溶质HBD酸度是两个主要因素。LSER结果表明，化合物发现SDS胶束环境的凝聚力略低于SC胶束（即，更非极性），而全氟辛烷磺酸锂胶束是最有凝聚力的三种表面活性剂的聚集体和1-辛醇提供最少的凝聚力的环境。另一方面，全氟辛烷磺酸锂的氟碳胶束是最强的氢键供体酸，其次是SDS，SC和1-辛醇，分别。SC胶束具有最强的氢键受体碱性，其次是正辛醇、SDS和LiPFOS胶束。可以得出结论，这些表面活性剂类型在MEKC中的选择性差异主要是由于氢键相互作用，而不是偶极相互作用。比较全氟表面活性剂和烃类表面活性剂，甚至溶质的大小也可以在选择性迁移模式中发挥作用。此外，从极性和疏水基团的选择性的信息证实了LSER的结论的基本相互作用，控制迁移行为和化学选择性的MEKC。本文是第一次尝试从这个实验室来描述的重要的相互作用，控制迁移模式MEKC。在胶束电动色谱（MEKC）中，12345678个不带电荷的分子被分离到胶束假固定相，这是基于它们在胶束假固定相中的微分分配。1-3 MEKC被认为是一种色谱技术的事实主要是分配机制的结果。与常规色谱一样，MEKC中相互作用相的化学性质在分离过程中起着重要作用。MEKC的一个主要优点是通过简单地用新的假固定相溶液冲洗毛细管来改变系统的化学组成的可行性。MEKC中的迁移行为可以...
The influence of surfactant type on migration behavior and chemical selectivity in micellar electrokinetic chromatog-raphy (MEKC) is investigated through linear solvation energy relationships (LSER) andfunctional group selec-tivities. In LSER modeling, solutes’ capacity factors are correlated withtheir structural descriptors such as size, dipolarity, and hydrogen-bonding abilities. Using the LSER methodology, useful information about the nature of solute interactions with different types of surfactant aggregates can be obtained since capacity factor in MEKC is directly related to solute distribution between the bulk aqueous solvent and micelles. High correlations were observed for different LSER models of migration behavior in MEKC for a group of 60 uncharged aromatic com-pounds of non-hydrogen bonding (NHB), hydrogen-bond-ing acceptor (HBA) bases, and hydrogen-bondingdonor (HBD) acids. In two anionic, hydrocarbon micellar systems of sodiumdodecyl sulfate (SDS) and sodium cholate (SC), retention is primarily influenced by the size of molecules and their hydrogen bond accepting basicity. Their dipolarity/polarizability andhydrogen bond donat-ing acidity play minor roles. Capacity factors of solutes in SDS and SC systems increase with their size and decrease for strongerhydrogen bond acceptor bases. These results are similar to those observed for other systems where hydrophobic interactions play a major role, eg, solute distribution in the 1-octanol-water solvent system or retention in reversed phase LC. In MEKC with an anionic fluorocarbon surfactant, lithium perfluorooctanesulfonate (LiPFOS), however, size and solute HBD acidity are the two predominant factors. The LSER results indicate that compounds find the SDS micellar environments slightly less cohesive (ie, more apolar) than the SC micelles, while the LiPFOS micelles are the most cohesive among the three surfactant aggregates and 1-oc-tanol provides the least cohesive environment The fluorocarbon micelles of LiPFOS, on the other hand, are the strongest hydrogen bond donor acids, followed by SDS, SC, and 1-octanol, respectively. The SC micelles have the most hydrogen bond acceptor basic characteristics, followed by 1-octanol, SDS, and LiPFOSmicelles. It can be concluded that selectivity differences between these surfactant types in MEKC is primarily due to hydrogen-bonding interactions rather than the dipolar interactions. Comparing the perfluorinated and the hy-drocarbon surfactants, even solute size can play a role in selective migration patterns. In addition, information from polar and hydrophobic group selectivities confirm the LSER conclusions about the underlying interactions that control migration behavior and chemical selectivity in MEKC. This paper is the first attempt from this laboratory to characterize the important interactions that control migration patterns in MEKC. A better understanding of these interactions may lead to classification of surfactant aggregates in terms of their chemical selec-tivity.In micellar electrokinetic chromatography (MEKC), 1 2345678un-charged molecules are separated on the basis of their differential partitioning into the micellar pseudostationary phase. 1-3 The fact that MEKC has been regarded as a chromatographic technique is primarily the result of the partitioning mechanism. As with conventional chromatography, the chemical nature of the interactive phase in MEKC plays an important role in the separation process. A main advantage of MEKC is the feasibility of changing the chemical composition of the system by simply rinsing the capillary with a solution of the new pseudostationary phase. Migration behavior in MEKC can then …