Ruiz-Angel M J, Carda-Broch S, Torres-Lapasió J R, García-Alvarez-Coque M C
Department of Analytical Chemistry, University of Valencia, c/Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
J Chromatogr A. 2009 Mar 6;1216(10):1798-814. doi: 10.1016/j.chroma.2008.09.053. Epub 2008 Sep 19.
Micellar liquid chromatography (MLC) is a reversed-phase liquid chromatographic (RPLC) mode with mobile phases containing a surfactant (ionic or non-ionic) above its critical micellar concentration (CMC). In these conditions, the stationary phase is modified with an approximately constant amount of surfactant monomers, and the solubilising capability of the mobile phase is altered by the presence of micelles, giving rise to diverse interactions (hydrophobic, ionic and steric) with major implications in retention and selectivity. From its beginnings in 1980, the technique has evolved up to becoming a real alternative in some instances (and a complement in others) to classical RPLC with hydro-organic mixtures, owing to its peculiar features and unique advantages. This review is aimed to describe the retention mechanisms (i.e. solute interactions with both stationary and mobile phases) in an MLC system, revealed in diverse reports where the retention behaviour of solutes of different nature (ionic or neutral exhibiting a wide range of polarities) has been studied in a variety of conditions (with ionic and non-ionic surfactants, added salt and organic solvent, and varying pH). The theory is supported by several mechanistic models that describe satisfactorily the retention behaviour, and allow the measurement of the strength of solute-stationary phase and solute-micelle interactions. Suppression of silanol activity, steric effects in the packing pores, anti-binding behaviour, retention of ionisable compounds, compensating effect on polarity differences among solutes, and the contribution of the solvation parameter model to elucidate the interactions in MLC, are commented.
胶束液相色谱法（MLC）是一种反相液相色谱（RPLC）模式，其流动相含有高于其临界胶束浓度（CMC）的表面活性剂（离子型或非离子型）。在这些条件下，固定相用近似恒定数量的表面活性剂单体进行改性，流动相的增溶能力因胶束的存在而改变，从而产生不同的相互作用（疏水、离子和空间相互作用），对保留和选择性有重要影响。自1980年诞生以来，由于其独特的特点和优势，该技术已发展成为在某些情况下（在其他情况下则作为补充）对传统的含有水-有机混合物的RPLC的一种真正替代方法。这篇综述旨在描述MLC系统中的保留机制（即溶质与固定相和流动相的相互作用），这些机制在各种报告中得到揭示，其中研究了不同性质（离子型或中性，具有广泛极性）的溶质在各种条件下（使用离子型和非离子型表面活性剂、添加盐和有机溶剂以及改变pH值）的保留行为。该理论得到了几个机理模型的支持，这些模型令人满意地描述了保留行为，并允许测量溶质-固定相和溶质-胶束相互作用的强度。文中还对硅醇活性的抑制、填充孔隙中的空间效应、抗结合行为、可电离化合物的保留、对溶质间极性差异的补偿作用以及溶剂化参数模型对阐明MLC中相互作用的贡献进行了评论。
