In continuation of a recent report1 on the chromatographic behaviour of metallic nitrates in the system methyl isobutyl ketone(MIBK)-nitric acid-water, we have now studied the distribution of nitric acid and lithium nitrate between water and MIBK, and have measured the Rp values of 55 ions in the above mixtures. A chromatographic study of a large number of ions in one given solvent system may yield numerous useful separations. The RF values obtained for cations may to a certain extent be related to the distribution coefficients for the same cations obtainable by' the extraction technique in the same solvent system. This relationship is rather imperfect, amongst other things, because of the influence of the solvent itself, and of its water and acid content, upon the cellulose and because of the changes in solvent composition that occur during the development of the chromatograms. Thus, a chromatographic study can serve only as a' preliminary, but it may provide a basis for possible separations of macro quantities by the extraction technique. With this aim in mind, it appeared necessary and important to carry out a systematic and detailed study of the solvent system itself. Up to the present no attention has been paid to the exact composition of the eluants used in paper chromatography: the distribution of acids, salting-out agents and complexing agents between the aqueous and organic layers has never been determined. A study of this problem should permit a more fundamental interpretation of the RF values obtained, and in certain cases is likely to serve as a basis for some theoretical considerations. In radiochemical processes where the dissolution of the fuel is generally carried out, with nitric acid, inorganic nitrates are often added to the nitric acid to increase the dissolution rate of the uranium2. Sometimes nitrates appear more promising than nitric acid as aqueous salting-out agents in the solution from which the extraction is to be made. Experiments have often shown 394 that a much higher partition coefficient is obtained when part of the nitric acid in the aqueous phase is replaced by neutral inorganic nitrates, which themselves are practically insoluble in the organic phases. ~0 In the case of extraction with MIBK, the partition coefficient of the extractable '".. species is dependent both on the concentration of nitric acid and of the. nitrates in the aqueous phase 0. The same was found for RF values in paper chromatographyr. It' is often sufficient to add nitrates to obtain the necessary salting-out strength without, RefeveTices p. 495. . . '..