Abstract: Method for the chromatographic analysis of a technetium-containing mixture of bound, reduced technetium; unbound, reduced technetium; and, free pertechnetate. A portion of the mixture is spotted on a chromatographic adsorbent, preferably cellulose-fiber paper, and is developed with an aqueous salt solution, preferably comprising sodium chloride and/or sodium pyrophosphate. The developed chromatogram has an isolated zone in which the unbound, reduced technetium is located. Simultaneously therewith, a second chromatogram is developed utilizing a suitable liquid organic solvent, preferably comprising a mixture of acetone and acetic acid. The developed chromatogram has an isolated zone in which the free pertechnetate is located. Radioactive measurements are made and the amounts of unbound, reduced technetium and of free pertechnetate are determined as proportions of total technetium. The amount of bound, reduced technetium may then be readily calculated.