Abstract The influence of pH on the mobilities of mono-, di-, and triphosphates of adenosine, guanosine, cytidine, and uridine in electrophoresis and chromatography on ion-exchange paper (Whatman DE 81) has been studied. Buffers composed of acetic acid and sodium citrate of different pH's have been used both for electrophoresis and for chromatography. The data are presented in a tabular and graphic form so that a suitable pH for a given separation can be found. Bidimensional electrochromatographies of the twelve nucleotides are also reported. Separations of mixtures can be obtained in times varying from a few minutes to 13 hr, depending on the complexity of mixtures.