Application of ionic liquids in the preparation of extraction chromatographic materials for metal ion separations: Progress and prospects

Over the last two decades, extraction chromatography, a form of liquid chromatography employing as the stationary phase any of a variety of extractants in an appropriate organic solvent sorbed on a solid support, has emerged as an important tool for a number of analytical- and preparative-scale metal ion separations. Recent studies in which ionic liquids (ILs) have been evaluated as replacements for the molecular solvents normally used in liquid-liquid extraction suggest that an improvement in the performance of extraction chromatographic materials might be effected by the use of an IL as the basis for the stationary phase. In this report, approaches to the preparation of new sorbents incorporating ILs are described and the performance of the resultant materials in various metal ion separations is reviewed. In addition, promising areas for future work are identified.