for radioactive antimony in the gamma spectrometer.
The oxalic acid fraction, which was observed to contain iron in
previous experiments, was analyzed for Fe55 by determining the
amount of absorption by an aluminumfilter of 4.7 mg/cm? using a
methane gas-flow counting chamber.
Because of the possibility that
some other nuclide might be contributing to this radioactivity,
an
ion-exchange separation based on Kraus and Moore's iL method for
divalent transition elements was made.
In this procedure the
oxalic acid fraction was ignited and redissolved in 12 M HCl] and
passed through a 0.28 cm 2 x 26-cm column of Dowex resin of
200-400 mesh at a flow rate of 0.2 ml/min.
Then,
8-13 ml of HCl
of the following molarities were added successively to the column:
12, 6, 4, 2.5, 0.5, 0.005 and 0.
column and ignited.
The resin was removed from the
The fractions were dried on stainless steel
planchets and counted.
The two aliquots with significant activity were
recounted with an aluminum filter of 4.7 mg/ cm? to filter out the
radiation from Fe),
The three pH 4. 1 fractions resulting from the Dowex 50 procedure
were combined, ashed, and redissolved in 0.2 N HCl for a secondary
ion-exchange separation with Dowex 50 to separate Ce, Cs, Co,
Mn.
and
In this procedure a 0. 28 cm* x 21-cm column of Dowex 50 of 100-
200 mesh was used.
The sample and solutions of 5 per cent ammonium
citrate at pH 2.8, 3.1, 3.3, and 6.1 were passed through the columnat