PREPARATION OF CARRIER-FREE Y-90 FOR MEDICAL APPLICATIONS BY SOLVENT-EXTRACTION CHROMATOGRAPHY

The separation of carrier-free Y-90 from fission product Sr-90 by solid supported solvent extraction chromatography was investigated using Teflon grain as solid support and a di-(2-ethylhexyl) phosphoric acid (D2EHPA) extraction agent as liquid phase. The optimum separation conditions are: (1) solid support using Dupont TF800 Teflon grains, (2) using 5% D2EHPA ''traction agent as liquid phase, (3) setting the flow rate. at 1 cm3/min; and (4) using a column diameter of 0.5 cm which was packed with 1 g treated Teflon. After loading Sr-90/Y-90 equilibrium solution, the loaded column was washed with 0.3 N hydrochloric acid to remove Sr-90 species; subsequently, 8 N hydrochloric acid was used as an eluent to obtain a Y-90 solution. Chemical yield was about 90%; radionuclide impurity of Sr-90 in the final product was < 10(-6)%. Consequently, the preparation of 1 mCi of Y-90 was satisfactory for radiolabeling in medical applications. A radiotracer method using Sr-85 and Y-88 was also developed to investigate separation efficiency.