MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY OF ACIDIC SOLUTES - MIGRATION BEHAVIOR AND OPTIMIZATION STRATEGIES
MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY OF ACIDIC SOLUTES - MIGRATION BEHAVIOR AND OPTIMIZATION STRATEGIES
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DOI：
10.1021/ac00017a029
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发表时间：
1991-09-01
影响因子：
7.4
通讯作者：
STRASTERS, JK
中科院分区：
文献类型：
--
作者：
KHALEDI, MG;SMITH, SC;STRASTERS, JK
胶束电动毛细管色谱法（MECC）适用于非带电溶质和带电溶质混合物的分离。本文用不同的模型定量描述了酸性化合物在MECC中的迁移行为。这些方程描述了MECC中两个迁移参数（保留系数和迁移率）与两个重要实验参数（pH和胶束浓度）之间的关系，这两个参数对迁移行为和选择性有很大影响。有趣的是，给定溶质的迁移率和保留系数可能随着ph的变化而表现不同。这将提出一个问题，即哪个参数实际上代表了MECC中溶质的迁移行为：保留系数（色谱参数）还是迁移率（电泳参数）。讨论了胶束介导的电离常数变化对MECC选择性和优化策略的影响。数学模型将允许基于有限数量的初始实验来预测溶质的迁移行为。这将极大地促进MECC分离可电离化合物方法的开发和优化，此外，还可以确定溶质的重要物理和化学特性，例如它们在胶束介质中的表观电离常数和它们在胶束中的分配系数（在宽pH值范围内）。模型得到了验证，因为预测的迁移行为与实验观察到的迁移行为很好地吻合。根据初步结果，pH和胶束浓度在许多情况下可能是相互作用的参数。因此，同时优化这两个参数将是提高MECC分离酸性溶质的最有效策略。
Micellar electrokinetic capillary chromatography (MECC) is suitable for the separation of mixtures of uncharged and charged solutes. In this paper, the migration behavior of acidic compounds in MECC is quantitatively described in terms of different models. These equations describe the relationships between the two migration parameters in MECC (retention factor and mobility) and the two important experimental parameters (pH and micelle concentration) that have a great influence on the migration behavior and selectivity. Interestingly, the mobility and retention factor of a given solute could behave differently with the variations in pH. This would raise a question of which parameter actually represents the migration behavior of a solute in MECC: retention factor (a chromatographic parameter) or mobility (an electrophoretic parameter). The consequences of micellar-mediated shifts of ionization constants on selectivity and optimization strategies in MECC are discussed. The mathematical models would allow the prediction of migration behavior of solutes based on a limited number of initial experiments. This would greatly facilitate the method development and optimization of separations of ionizable compounds by MECC and, in addition, important physical and chemical characteristics of solutes such as their apparent ionization constants in micellar media and their partition coefficients into micelles (over a wide range pH values) can be determined. The models were verified, as good agreements were observed between the predicted and the experimentally observed migration behavior. Based on the preliminary results, the pH and micelle concentration are likely to be interactive parameters in many situations. As a result, simultaneous optimization of these two parameters would be the most effective strategy to enhance the MECC separation of acidic solutes.