Interesting separations of metal ions were observed by using the technique of reverse phase partition chromatography on 2-thenoyltrifluoroacetone—impregnated paper. Ketone-hydrochloric acid mixtures in different proportions were used as the developing solvent for the separations of different metal ion mixtures. The RFvalues of metal ions separated are given and the superiority of separation over that of ordinary filter paper is discussed.