Radiochemical determination of technetium-99

A procedure has been developed for the determination of 99Tc in vegetation, by use of sup(95m)Tc as an internal tracer. The samples are wet-ashed, without significant loss of Tc. The Tc is separated from most other radionuclides by precipitation with calcium carbonate, and is purified by anion-exchange chromatography and electro-deposition. The radiochemical yield of Tc is determined by Ge(Li) gamma-ray spectrometry of the 204-keV photon peak of the sup(95m)Tc internal tracer, and the 99Tc activity is determined by counting its 0.292-MeV beta-particles with a scintillation counter. The detection limit for 99Tc in a sample weighing about 10 g is 0.1 pCi for a 3000-min count. (author)