We have developed cleanroom compatible techniques for processing bone samples for characterization of their uranium and plutonium
content. The bone samples are dried and ashed in quartz crucibles placed inside cleanroom compatible thermal ashing furnaces.
The bone ash is dissolved in ultra-pure acids prepared by sub-boiling distillation. The uranium and plutonium in the samples
are isolated and purified by ion-exchange chromatography and measured by thermal ionization mass spectrometry. The technique
is capable of detecting 74 picograms of 238U and 8 femtograms of 239Pu in 100 mg bone ash samples. If the ash contains larger amounts of uranium and plutonium, the technique can be used to isotopically
fingerprint the material to identify potential origins.