sample is ashed and then treated with HF, HNO3, and H3B03 so as to completely
dissolve the transuranium elements.
Over the years, various methods have been developed for the wet
large tissue samples. A combination of HNO3, F-HNO3, and HC10,
successfully but is time consuming and requires almost constant
(NCRH, 1967). Also, insoluble (NH,)2 C10, salts interfere with
ashing of
has been used
attention
the dissolution.
Another method (Major and Wessman, 1964) utilizing a reflux action with
H,S0, and an Hg catalyst was developed but was still time consuming. B. Sansoni
and Kracke (1971) reported a very adequate method of using H202 in the presence
of Fe++ ion.
The method reported here is simple and economical, particularly for large high
activity samples.
The method offers a self-contained easy contamination
control as shown in the procedure schematic Figure l.
PROCEDURE
Cut the wet soft tissue sample (up to 250 g)
into small cubes for dissolution.
If a dry weight is required, then dry the sample in an oven at 105° C for 24
hours. Weigh the dried meat and repeat the drying and weighing at 6 hour
intervals until a constant weight is obtained. In some cases, the ash content
of the sample is required.
It is suggested that a representative aliquot of
the wet sample be taken for ash determination and that the ash be dissolved
and recombined with the original sample.
Transfer the sample to a 2-liter wide-mouth poly bottle.
The reacting solution
may foam over if too much meat is used.
Add an equal weight of HNO3 and 10 ml
of HF to the bottle.
CAUTION:
Cap the bottle but be sure it is loose so that
the gases may escape during the reaction.
Place the bottle in a hot water
bath and heat on a hot plate until all the foaming reaction stops.
saturated H3B03, and continue heating for 20 minutes.
Add 10 ml
Transfer the solution
into a glass beaker and wash the bottle with hot 6N HNO3.
Any fat will float
to the top upon standing at this time and the aqueous phase should be clear.
If a smaller volume is required, evaporate the solution to a smaller volume.
Do not evaporate to dryness since some organics are present and the solution
will turn into a black tar.
Cool the sample to solidify the fat and filter it
through a No. 541 Whatman filter paper.
In some cases, the fat may be discarded
at this point. Otherwise, ash the filtered fat ina 425° C furnace and dissolve
the ash with HNO3, HF, and H3B03. Combine the resulting solution with the
filtrate. Dilute the sample to 1,000 gram with 6N HNO3,
The solubilized tissue sample is aliquoted for transuranium analysis. The
aliquot is equilibrated with tracer by boiling in HNO3 with added H,05. If
Pu is being analyzed, the sample is cooled and NaNQ> added so that the final
solution is 6-8N HNO3 and ready for an anion column separation of Pu and Np
from Am and Cm.
The analyses are then completed by the appropriate method.
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