Paper Chromatography of Potassium, Rubidium and Cæsium

Abstract

ALTHOUGH the separation of lithium, sodium and potassium by paper chromatography is not difficult, only three mixtures of solvents seem to have been proposed to accomplish the chromatographic separation of potassium, rubidium and cæsium. A. E. Steel¹ recommended the use of a saturated solution of phenol in hydrochloric acid; but the chromatograms run under these conditions do not give reproducible R _F-values. Separation has also been obtained by the method of C. C. Miller and R. J. Magee², with a solvent consisting of concentrated hydrochloric acid/methanol/n-butanol/isobutylmethyl ketone (55 : 35 : 5 : 5 v/v). Recently, R. J. Magee and J. B. Headridge³ claimed better results for the chlorides of lithium and sodium, and of potassium, rubidium, cæsium and ammonium, using a phenol/methanol/concentrated hydrochloric acid mixture (57.5 : 22.5 : 20 per cent w/v/v).