Application of Cloud Point Extraction for Separation and Analyses of Actinides and Lanthanides

Cloud point extraction(CPE) is an extraction method with high concentration coefficient, low cost and safety, which has been widely used in analytical chemistry for metal ion analyses. As the sample composition of actinides and lanthanides is usually complicated and their concentrations are very low, their separation and analyses have become a significant issue in the field of radiochemistry. After optimization of extraction conditions, CPE can selectively separate and concentrate actinides and lanthanides. Combining with various technologies, CPE can achieve high sensitivity in analyses of actinides and lanthanides. Based on the CPE mechanism, we put an emphasis on the effects of different extractants (e.g., β-diketone, phosphine oxide, nitrogen and sulfur containing extractants) on actinides and lanthanides in various extraction systems. We also summarize the coupling techniques in CPE and describe attempts on constructing supramolecular recognition sites, altering ligands, using diverse surfactants and masking agents to improve the existing CPE systems. Besides, the perspectives of cloud point extraction in the field of radiochemistry are presented.