Carrier-free radioactive isotopes were separated with a column-chromatographic method combined with electrolysis. An autoradiographic method was used to study the motion, during elution, of radioactive material deposited on an anodically-polarized platinum powder column. The variation of the equilibrium distribution coefficient, which determines the rate of elution, was examined as functions of the terminal voltage and the hydrogen ion concentration. By means of an isotherm method, the changes in the number of active centres characteristic of the anodic deposition were determined as functions of the terminal voltage and the hydrogen ion concentration.