A column-chromatographic system using DEAE-cellulose and gradient elution with triethylammonium formate at pH4.0–3.5 is described. It is capable of separating the oligonucleotide isonicotinoyl hydrazones that are produced by nuclease digestion of RNA oxidized with periodate and coupled with isonicotinic acid hydrazide. Fifteen dinucleoside monophosphate isonicotinoyl hydrazones were characterized by their elution positions on the columns, so that all but two of them could readily be identified. Twelve trinucleoside diphosphate hydrazones were also characterized by their elution positions on the column. The application of this method of fractionation to terminal-sequence studies of RNA is discussed.
