Solvent extraction in analytical chemistry and separation science.

Abstract

Solvent extraction has long enjoyed a well-deserved position of prominence among anlytical chemists as a powerful separation technique applicable both to trace and macro levels of materials. Solvent extraction chemistry has developed in a most dramatic way in the last quarter of a century. Work in this area has not only provided the basis for a rich store of analytical methodology characterized by high sensitivity and selectivity, but has also illuminated many fundamental aspects of a wide variety of inorganic coordination complex reactions. Because of the great range of concentrations from weightless trace levels of carrier-free radioisotopes to the macro levels of several weight per cent of metal ions in which quantitative separations by solvent extraction is applicable, this technique is equally useful in both analytical and preparative, e.g. process scale, modes. The continuing vigor of this interesting field is attested by the continuing high publication rate of research reports from active groups throughout the world (about 1000 papers annually). It is not daring to predict that much innovative and fruitful research in both fundamental and applied research will be conducted in the next decade or two.Despite the great variety of extraction systems it is possible to describe every extraction by a simple, three step scheme (Table 1).