The Separation of Alkali Metals as Poly-Iodides by Reversed-Phase Partition Chromatography

Abstract

The liquid-liquid extraction of alkali metal ions as their poly-iodides had previously been investigated by the present author. In order to attain a good separation of each metal, this extraction system has now been extended to a reversed-phase partition chromatography in which Kel-F powder was used to support the organic phase of nitrobenzene-iodine-iodide. Column chromatographic separation was carried out in the presence of relatively large amounts of the metals by elution with water and 1 n or 6 n hydrochloric acid - eluting solutions. Chromatographic behavior of each metal ion was investigated and the elution from the column was found to be in the order of Li-Na-K-Rb-Cs. The distribution ratio of the metal ions varied with the quantity of the ions loaded on the column; the smaller the quantity of the ions used, the larger was the distribution ratio obtained. The actual separation of individual metal ions from the mixture was successfully achieved; a minute amount of cesium could be particularly isolated from large amounts of other alkali metals, even in a large volume of the sample solution. Elution curves of various amounts of metal were obtained as an aid to a discussion of the partition on the column. A comparison of the distribution ratio in the liquid-liquid extraction with that in the column chromatography showed that the extraction of the same mechanism proceeded in both cases.