RESUMO
An ion exchange method has been developed to separate no-carrier-added 64Cu from irradiated Ni target. The target is first dissolved in nitric acid and the solution is evaporated to dryness and the residue is dissolved in an ethanol-HCl solution. Cu, Co and Ni in ethanol-HCl solution are then absorbed on an anion exchange column. Co and Ni are removed from the column by eluting with 72% ethanol-0.3 mol/l HCl. Finally, the 64Cu is eluted with water. For separating Ni from Co isotopes and recovering the 64Ni target, the eluate of 72% ethanol-0.3 mol/l HCl is evaporated to dryness, the residue is dissolved in a concentrated HCl solution, and loaded to an another column, Ni is eluted by 9 mol/l HCl, while Co remains on the column. The procedure developed has been successfully applied for the production of no-carrier-added 64Cu from enriched 64Ni generated by the reaction 64Ni(p,n)64Cu using a cyclotron. The decontamination of Co in Cu fraction is higher than 99% and recoveries of 64Cu and 64Ni are higher than 95%.
RESUMO
An often overlooked problem in the use of radiotracers is the possibility of isotopic contamination. Commercially available silver 110mAg was used to study silver uptake and depuration in rainbow trout and European eel. Quality control by means of comparative gamma and beta counting brought our attention to a contamination of the 110mAg stock with 109Cd, which could be seen only because the 109Cd was markedly bioconcentrated by trout gills. The contamination could not be detected in eel gills or in other tissues of both species. The difference between trout and eel gill structure and function is the probable explanation for the marked difference in 109Cd accumulation. This contamination was identified as 109Cd by gamma spectroscopy and its origin by transmutation of natural silver as a result of neutron activation is described. Failure to recognize this contamination problem would have resulted in serious misinterpretation of the data set. Guidance for avoiding this problem is given.
