Abstract

A two‐dimensional fractionation procedure has been developed for separating radioactively‐labelled oligonucleotides of up to 50 residues long, using uniformly 32 P‐labelled 5S RNA of Escherichia coli as a model compound. The method uses ionophoresis on cellulose acetate at pH 3.5 in the first dimension; and ascending chromatography with a concentrated mixture of oligonucleotides on thin layers of mixed DEAE‐cellulose and cellulose in the second dimension.