i . j ii 3 j : j i of oh i 4 LT |B ey at ow 4 ; 4 4 1 ; - af ray rE \ 35& K. M. WONG Weigh the wet organisms (dissected if necessary). take out the properaliquot, h 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 n 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 OS. row a 4 gr of wet resin in a 1.5-cm id. x 30 cm column. C 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 nl ar 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 , | Add 5 ml of 12 M hydrochloric acid, warm the solution on a hot plate for a | f ) 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 lo pl fo an ot 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 5904283 : in the procedure for sediments. eH Fi i CF re |: EG 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 i: Si is minimized. Wet the ashed sample with water and add | ml of standardized pluto- f i FAS EE Lf FE Tie He E n 03 be du Ph ac. dif ex! un me fro or: co] IS § cor { 4b. =. rec anc abc