Separation of alkali metals by extraction chromatography with dipicrylamine and nitrobenzene

An extraction chromatographic method to separate rubidium and cesium using a nitrobenzene solution of ammonium dipicrylaminate has been developed. The procedure is used in connection with a concentration-dependent radioisotope distribution method for determining traces of cesium in rubidium salts. A frontal chromatographic enrichment method to eliminate excess sodium, lithium and calcium salts has been worked out. The results are compared with the conclusions drawn from the extraction mechanism and with other separation procedures. Part VIII of the series “The method of concentration-dependent distribution in the quantitative use of radioisotopes”; for Part VII, seeChem. Listy, 61 (1967) 440.