Dispersive liquid-liquid microextraction for chemical speciation and determination of ultra-trace concentrations of metal ions

Recent years have seen an upsurge of interest in developing a low-cost, easy-to-operate, reliable preconcentration technique for precise determination of ultra-trace concentrations of metal ions in aqueous matrices. Dispersive liquid-liquid microextraction (DLLME) is a novel sample-preparation technique offering high enrichment factors from low volumes of water samples. We compare DLLME, cloud-point extraction and other microextraction techniques. We also highlight the current best practices for analysis and chemical speciation of metal ions in highly salted media. We strongly recommend the stripping voltammetric technique at modified electrodes coupled to DLLME and other microextraction techniques to develop low-cost, precise methods for ultra-trace concentrations of metal ions in biological and environmental samples. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.