21aqueous solvents are used on ion-exchange papers simplifies the requirements of an apparatus and virtually eliminates some sources of irreproducible results on a conventional paper chromatogram.Ion-exchange papers may be converted into different counter ionic forms by means of a descending chromatographic wash with a suitable aqueous solution followed by a water wash and drying. Such a procedure leads to the use of a .. dry method" of development. Alternatively, a .. wet method" of development may be more suitable in which case the final water wash is omitted and after careful blotting or otherwise draining of the paper the mixture to be separated is applied directly to the wet paper for development.The stationary phase in conventional paper chromatography is regarded as the cellulose itself which makes this phase virtually invariable chemically. Variations in performance on such a chromatogram occur mainly via changes in the developing solvent system. In ion-exchange paper chromatography the variety of functional groups and the matrices to which these are attached confer wide powers of control on the stationary phase with a smaller emphasis being placed on the mobile phase.A comparison of separations of amino acids on various ion-exchange papers show wide changes in relative rates of movement of individual components of a mixture as the functional group changes from anionic to cationic and the exchanger matrix from hydrophilic cellulose to hydrophobic resin. The importance of the effect of the exchanger matrix is emphasised in the reversal of sequence within certain groups of amino acids on changing the exchanger matrix while the functional groups remains virtually the same. The direction of the matrix interaction effect is such that it allows a higher resolution of amino acids on a cation exchange resin compared to a cation exchange cellulose and on an anion exchange cellulose compared to an anion exchange resin.A new two-dimensional method combining ion-exchange separations in one direction with .. partition type" separation in the second allows an increased potential resolution of complex amino acid mixtures on ion-exchange papers relative to conventional papers on which two different solvent systems are combined. An order of increasing resolving powers of the papers is conventional < cellulose phosphate < DEAE cellulose< sulphonated polystyrene resin loaded.