COMPLEX EQUILIBRIA IN CAPILLARY ZONE ELECTROPHORESIS AND THEIR USE FOR THE SEPARATION OF RARE-EARTH-METAL IONS

The separation of lanthanides by capillary zone electrophoresis is car ried out by addition of a complex forming agent to the separation buff er, thus generating charge and mobility differences between the specie s. The choice of a suitable ligand and especially the precalculation o f the optimum ligand concentration is possible if the stability consta nts of the complexes are known. In this paper the relation between the calculated concentrations and the quality of separation at these conc entrations is demonstrated. Furthermore, the influence of pH on the se paration with hydroxyisobutyric acid is investigated as an example.