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K. M. WONG
Weigh the wet organisms (dissected if necessary). take out the properaliquot,
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oxidized. Do not ash above 500° *. Weigh the ash. Transfer the ash to a glass beaker.
Since carbonates are formed during ashing. the initial reaction of the ash with acid is
very vigorous; allow sufficient room in the selection of beaker so that spattering loss
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dry to constant weight at 105°. and ash at 450-475° until all the organic material has
7
Plutonium purification procedure
Pass the sample solution obtained bv the above steps. through an anionexchange column pre-conditioned with 8 M nitric acid. For sea-water samples, use
10 mi of wet resin in a 1-cm i.d. x 20 cm column. and for sediment samples use 25 ml
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of wet resin in a 1.5-cm id. x 30 cm column.
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10 ml min” '. Using a 2-ml disposable glass pipet. rinse the column wall with 8 M
nitric acid; drain the rinse solution carefully to the top of the resin. Repeat the rinse
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Allow the sample solution to drain to the top of the resin at a flow rate of about
and draining step once. Elute the column with 30 ml of 8 Mnitric acid, drain carefully
to the top of the resin and discard the eluate. Elute as above with 30 ml of 12 M
hydrochloric acid and discard this eluate.
:
Elute the piutonium with a solution of 30 ml of 16 M hydrochloric acid and
1 ml of 1 M ammonium iodide. Mix this eluant solution just before use. Collect the
eluate in a 100-ml beaker, and evaporate below boiling to dryness on a hotplate.
by
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Add 5 ml of 12 M hydrochloric acid, warm the solution on a hot plate for a
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the top of the resin each time. Wash the column with 20 ml of 12 M hydrochloric acid.
.
7
remove the ammoniumsalts as described above.
Electroplate the plutonium on stainless steel plating discs as described
previously*, count, and resolve the activity by a-spectrometry.
RESULTS AND DISCUSSION
This procedure has routinely been inserted into the sequential scheme® for
analysis of fall-out radionuclides in sea water and other marine samples. The iron(IJ}
Anal. Chim. Acta, 56 (1971) 355-364
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Remove the ammoniumsalts by evaporation with several portions of 2-3 ml each of
16 M nitric acid and 12 M hydrochloric acid. Rinse the wall of the beaker with each
addition of acid. When the ammonium salts have evaporated, add a final rinse of
2-3 ml of 12 M hydrochloric acid, and evaporate the sample to dryness.
Discard the eluate. Elute the plutonium with 20 ml of 12 M hydrochloric acid and ! ml
of 1 M ammonium iodide (mixed just before use).
Collect the plutonium eluant in a 50-ml beaker, and slowly evaporate to
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in the procedure for sediments.
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nium-236 tracer. Proceed with the digestion and separation of plutonium asdescribed
few minutes, and transfer to a 50-ml centrifuge tube. Rinse the beaker twice with
2-3 ml of 12 M hydrochloric acid and combine the solutions. Add ca. 100 mg of
solid sodium nitrite. stir with a glass stirring rod, and allow to react for about 30 min.
Centrifuge at low speed for 2-3 min. Transfer the supernate to the top of small ionexchange column,loaded with 2 ml of wet AG 1-X8 resin preconditioned with 12 M
hydrochloric acid. Drain the solution to the top of the resin, and rinse the tube and
column walls twice with I-ml portions of hydrochloric acid, draining carefully to
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is minimized. Wet the ashed sample with water and add | ml of standardized pluto-
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