Ion-exclusion chromatography of compounds of biological interest

The principle of ion exclusion was examined as a method for the separation of small ionic compounds. The systems employed consisted of very porous column packings, substituted with fixed charges, which were eluted by buffer solutions of low ionic strength. DEAE-Sephadex A-50 was principally employed, and it was shown that there was a linear relationship between the net charge on a cation and its partition coefficient into the gel phase. A similar relationship existed in the chromatography of amino acids on various columns bearing fixed negative charges. It was concluded that this was an efficient form of chromatography, which gave results directly related to the ionic charge of the sample being examined. The charge characteristics of biologically active compound could be determined by this method.