Application of Ionic Liquids in Liquid Chromatography

Interest in ionic liquids (ILs) for their potential application in analytical chemistry continues to grow. Their usefulness can be due to favourable physicochemical properties, like the lack of vapour pressure, good thermal and chemical stability as well as very good dissolution properties regarding both organic and inorganic compounds. A specific feature of ILs is that these compounds provide strong proton donor-acceptor intermolecular interactions. As a result, ILs are able to affect on the hydroxy groups of the silica supports the most popular stationary phases in liquid chromatography (LC). It is well known that the hydroxy groups, called free or isolated silanols cause serious problems in LC, especially when separating basic compounds. This review focuses on the application of ILs in LC and capillary electrophoresis (CE) and comparisons of their efficiency with standard silanol suppressing additives to mobile phases.