44 by a small plug of glass wool at the drawn end (Fig. 4). (2) To cleanse the resin of water-soluble residues, a preparatory treatment was employed, based on a method for the preparation of "nuclear grade" resins 1960). (Chemical Process Co., Successive elutions of each colum were made as Step Eluant Quantity (m1) 1. CH30H 10 2. 3. 4, 5. 6. 7. 8. 9. Deionized water 12M HCl Deionized water 0.25M NaoQH 1.0M NaOH Deionized water QO.1M HCl 2M HCl 25 10 25 10 10 25 20 10 From the 2M sample solution, follows: Fe*+ and gn** were adsorbed on the resin as negatively charged chloride complexes while the non-complexed cations including niet, through the columns. Mn**, and cu2t passed Fe*+ was eluted selectively from the columns with 10 ml of 0.5M HCl, and zn2+ with 25 ml of 0.005M HCl. (II) Determination. The determination of zinc was based on a mixed-color colorimetric method described by Sandell (1959). The zinc (0.005M) fraction from each separation was evaporated and the residue taken up in 10 ml of deionized water. Separatory funnels of 60 ml capacity were filled with 20 ml of deionized water buffered to pH 4.75 with 5 drops of

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