-5- Rul06-Rp106, 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 Celd4_prld4 | Mn>4, C057,58,60, ana zn65*. Csi37, ammonium citrate at pH 4.1 removed 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 1, 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. 12M, 6M, The elutrients included 10 ml each of 4M, 2.5M, and 0.5M HCl, 20 ml of .005M HC1, and 10 ml of HoO. Under the conditions of the experiment Mn54 vas eluted in the 12M wash, Co27»58,60 in the 6M fraction, and zn©5 in .005M HCl. DOE ARCHIVES From the fractions eluted out of the Dowex 50 column one-ml aliquots of the HC1 fractions were dried, treated with *These radioisotopes were subsequently separated from each other on a second column. /oO