-5- 
Rul06-ppl06, The cations that were adsorbed onto the resin 
were differentially removed next by passing 40 ml of 0.5 
per cent oxalic acid and 40 ml each of 5 per cent ammonium 
citrate solutions at pH 3.5, 4.1, 5.1, and 6.1 through the 
column. Oxalic acid removed cationic Zr95-Nb95 and Fe55. 
Ammonium citrate at pH 3.5 removed Cel44_ppl 44 mn 4 | 
Co>?,58,60, ana zn©5*, Ammonium citrate at pH 4.1 removed 
Cs137, No radioisotopes were detected in the pH 5.1 or 
6.1 fractions when the fractions were counted for beta or 
gamma activity. 
The pH 3.5 fractions were dried, wet ashed and re- 
dissolved in 5 ml of concentrated HCl (12M) and run through 
a column (7 mm x 250 mm) of an anionic resin, Dowex l, to 
separate Mn, Co, and Zn from each other according to the 
method of Kraus and Moore (15). The sample was added to the 
column and the fractions were eluted at a flow rate of 0.1 
to 0.2 ml per minute. The elutrients included 10 ml each of 
10M, 6M, 4M, 2.5M, and 0.5M HCl, 20 ml of .005M HCl, and 10 
ml of Ho0. Under the conditions of the experiment Mn>4 was 
eluted in the 12M wash, Co57,58,60 in the 6m fraction, and 
zn©5 in .005M HCl. 
From the fractions eluted out of the Dowex 50 column 
one-ml aliquots of the HCl fractions were dried, treated with 
*These radioisotopes were subsequently separated from each 
other on a second column. 
