ABSTRACT
Ion-pair extraction has found a wide application in solvent extraction and chromatography. An improvement in the selectivity of the extraction procedure can sometimes be achieved by using a selective complexing agent in combination with a counterion of suitable hydrophobicity. Estimation of the conditions for quantitative extraction or separation is easily made if the extraction constants are known. Acids and bases acquire on protolysis a change in charge that strongly affects their distribution in uncharged form and as ion pairs. Ion-pair dissociation in the organic phase can have a significant influence on the isolation of a trace component in a sample. The differences in the distribution ratio between the sample components can be improved by using phase materials with selective interactions with the sample components. Ion-pair extraction can also be combined with complexation in the organic phase. Enantiomeric ions can also be separated with an enantiomeric counterion as the chiral selector.
