Buchberger Wolfgang
Institut für Analytische Chemie, Universität Linz, TNF-Tower, T 209, Altenbergerstraße 69, Linz, 4040, Austria.
Methods Mol Biol. 2016;1483:91-109. doi: 10.1007/978-1-4939-6403-1_6.
Microemulsion electrokinetic chromatography (MEEKC) is a special mode of capillary electrophoresis employing a microemulsion as carrier electrolyte. Analytes may partition between the aqueous phase of the microemulsion and its oil droplets which act as a pseudostationary phase. The technique is well suited for the separation of neutral species, in which case charged oil droplets (obtained by addition of an anionic or cationic surfactant) are present. A single set of separation parameters may be sufficient for separation of a wide range of analytes belonging to quite different chemical classes. Fine-tuning of resolution and analysis time may be achieved by addition of organic solvents, by changes in the nature of the surfactants (and cosurfactants) used to stabilize the microemulsion, or by various additives that may undergo some additional interactions with the analytes. Besides the separation of neutral analytes (which may be the most important application area of MEEKC), it can also be employed for cationic and/or anionic species. In this chapter, MEEKC conditions are summarized that have proven their reliability for routine analysis. Furthermore, the mechanisms encountered in MEEKC allow an efficient on-capillary preconcentration of analytes, so that the problem of poor concentration sensitivity of ultraviolet absorbance detection is circumvented.
微乳液电动色谱法（MEEKC）是毛细管电泳的一种特殊模式，它采用微乳液作为载体电解质。分析物可在微乳液的水相及其充当假固定相的油滴之间进行分配。该技术非常适合分离中性物质，在这种情况下会存在带电油滴（通过添加阴离子或阳离子表面活性剂获得）。对于分离属于完全不同化学类别的多种分析物，一组单一的分离参数可能就足够了。通过添加有机溶剂、改变用于稳定微乳液的表面活性剂（和助表面活性剂）的性质或通过可能与分析物发生一些额外相互作用的各种添加剂，可以实现分辨率和分析时间的微调。除了分离中性分析物（这可能是MEEKC最重要的应用领域）外，它还可用于阳离子和/或阴离子物质的分离。在本章中，总结了已证明其在常规分析中可靠性的MEEKC条件。此外，MEEKC中遇到的机制允许对分析物进行高效的柱上预富集，从而规避了紫外吸收检测浓度灵敏度差的问题。
