THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

Procedure
m. Pipet tie samples (2~in HC1 or HN03) into 40-ml long taper
conical centrifuge tubes. (1 -ml aliquots are used if possible. although aliquots as
large as 25 ml can be taken if necessary). If tracer or spike is added to 1 or 2 of ~
the samples, make the others up to the same volume with a solution of acid strength
identical to that of the tracer or spike. Stir.
=. Add 1-2 drops of La carrier ad then 2-4 drops of NH20H” HC1
per ml of solution. Make the solution at least 2.5 ~ in HF by addition of cone.
reagent (Note 1). Agitate the solution and permit to stand for 5 min after the addi-
tion of each of the above reagents.
=. Centrifuge and discard the supernate.
Step 4. Wash the precipitate with about 0.5 ml of 2 ~ HF-2 ~ HN03
solution. Stir, centrifuge and discard the supernate.
Step 5. Dissolve the LaF3 precipitate by adding 1 drop of saturated
H3B03 solution, stirring, and then adding cone. HC1 to a volume of 1.5- 2.0 ml. The
solution may be warmed if necessary.
=. Transfer the solution to a 5-cm Dowex A-1 resin column (see
Note 4 of Np procedure) which has been washed with 1-2 column volumes (Note 2) of
Solution I (Note 3). Wash the centrifuge tube with two 1-ml’ aliquots of Solution I.
The washes may be driven through the column with air pressure if so desired. The
effluent solutions from these washes may be used for the Am and Cm determinations;
if not to be so used the washes are discarded.
Step 7. Wash the sides of the centrifuge tube with 1.5 ml of cone. HC1,
wash and remove the Pt stirring rods, centrifuge and pass the solution through the
column with the use of pressure.
=. Add a few cryst~s of ~20H” HC1 direc~y to the top of the resin
column. (This helps to prevent immediate oxidation of the HI solution by any traces
of HN03 remaining on the column. ) Wash the centrifuge tube with 1.5 ml of cone.
HC1, transfer the washings to the column, and permit them to pass through. The
column should not be permitted to run dry while air pressure is being applied to it,
since air bubbles will be forced into the column and channeling and erratic elution of
activity may occur,
&I& 1-2 ml of tie HI-HC1 elutriant is put on the top of the col~n and
no pressure is applied during elution. The dark band of the elutriant may be seen
migrating down the column. The activity appears to be concentrated about the lower
edge of the elutriant band and most of it comes off in a 6- to 8-drop peak. However,
to obtain quantitative yields, drop collection is begun on a 2-in. Pt disk when the band
is about 0.8 cm from the end of the column, and collection is continued for 10-15
drops after the band has reached the end of the column. This allows for possible
irregularities in the band or misjudgements regarding its position. The drops taken
before the band reaches the end of the column are arranged on the periphery of the Pt
disk, and those which are expected to contain most of the activity are collected near
the center. The drops are not permitted to run together.
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