Micelle-mediated extraction as a tool for separation and preconcentration in metal analysis

Micelle-based techniques can be utilised for the pre-concentration and separation of metal ions, which are either in their native form or in chelates that are produced after reaction under appropriate conditions. In this review, the metal analysis is based on an a priori phase separation in aqueous micellar solutions. In principle, the micelle-mediated extraction technique involves cloud-point extraction, but this review also deals with micellar-enhanced ultrafiltration and reversed micellar phase extraction. The different aspects of surfactant-enhanced, non-classical, metal-extraction schemes are presented and the interactions with the micellar entity are given. The fundamentals of micellar solutions and their solubilization capabilities are highlighted. Also outlined are practical problems when this sort of extraction is implemented in conjunction with different analytical detection systems. (C) 2002 Published by Elsevier Science B.V. All rights reserved.