~8-
The resin was then added to the column and 30 ml of 12 M HCl
were allowed to pass through under pressure at a flow rate of
0.1-0.2 ml per minute to remove the iron impurities in the resin.
The sample was added to the column and the eluates were collected
as described above at a flow rate of 0.5 ml per minute.
Next,
8-13 ml of the following molarities of HCl were added succes-
sively: 12, 6, 4, 2.5, 0.5, 0,005 and 0, and the fractions were
collected separately.
The resin was removed from the column and
ignited for assay.
4,
Identification of the nuclides present in the fractions
One-ml aliquots of each oxalate or citrate fraction were
placed on stainless steel planchets 14 inches in diameter, dried
under heat lamps, and counted in a methane gas-flow chamber or
an end window counter containing a 2-inch diameter Anton Geiger
tube.
The HCl fractions, however, were first taken to dryness,
treated with a few drops of concentrated nitric acid, dried, and
rediluted to the original volume with water.
One-ml aliquots
of these fractions were then placed on stainless steel planchets
as above and dried.
The remainders of the fractions containing significant
amounts of radioactivity were dried and analyzed in a singlechannel, 50~position, automatic-advance, gamma spectrometer using
a 2-inch, well-type sodium lodide crystal.
and 8
Radioactive decays
mass absorption curves were obtained for some of these
fractions.
Correction factors for converting 8
and %
counts to
disintegrations per minute were calculated by the use of standards