The Separation of Alkaline Earth Metals as Their TTA-Complexes by Reversed-Phase Partition Chromatography

Abstract

Abstract The author’s preceding work, the liquid-liquid extraction of alkaline earth metals with TTA-MIBK, has now been extended to a reversed-phase partition chromatography in order to attain a good separation of the metal ions. The method was carried out with relatively large amounts of the metals through a column of Kel-F on which the organic phase of 1.5 m TTA-MIBK was supported. Elution was performed with 0.5 m buffer solutions, of various pH values, consisting of acetic acid, ammonium acetate and aqueous ammonia. The actual separation of each metal ion from the mixture of alkaline earth metals was achieved; the results are shown in several figures. The dependence of the distribution ratio on the pH of the solution and on the concentration of TTA in the stationary phase was examined from the elution curves; it might be considered that the same relation held as in the case of the liquid-liquid extraction system. Other experiments were then carried out in order to clarify the behavior of the TTA-chelates in the presence of a large amount of TTA; it was found that all of the TTA in the system participated in the effective extraction of the metal ion. The steps in the formation of the higher TTA-chelate in the column are depicted by the break-through curve of the chromatographic process.