Abstract
There is growing demand for separation of (90)Y carrier free from (90)Sr coexisting to produce high purity (90)Y essential for radiopharmaceutical uses. Thus, in this context the sorption profiles of Y(3+) and Sr(2+) from aqueous solutions containing diethylenetriaminepenta acetic acid (DTPA), ethylenediaminetetra-acetic acid (EDTA), acetic acid, citric acid, or NaCl onto Chelex-100 (anion ion exchange) solid sorbent were critically studied for developing an efficient and low-cost methodology for selective separation of Y(3+) from Sr(2+) ions (1.0 × 10(-5) M). Batch experiments displayed relative chemical extraction percentage (98 ± 5.4%) of Y(3+) from aqueous acetic acid solution onto Chelex-100 (anion ion exchanger), whereas Sr(2+) species showed no sorption. Hence, a selective separation of Y(3+) from its parent (90)Sr(2+) has been established based upon percolation of the aqueous solution of Y(3+) and Sr(2+) ions containing acetic acid at pH 1-2 through Chelex-100 sorbent packed column at a 2 mL min(-1) flow rate. Y(3+) species were retained quantitatively while Sr(2+) ions were not sorbed and passed through the sorbent packed column without extraction. The sorbed Y(3+) species were then recovered from the sorbent packed column with HNO(3) (1.0 M) at a 1.0 mL min(-1) flow rate. A dual extraction mechanism comprising absorption associated to "weak-base anion exchanger" and "solvent extraction" of Y(3+) as (YCl(6))(3-) and an extra part for "surface adsorption" of Y(3+) by the sorbent is proposed. The established method was validated by measuring the radiochemical (99.2 ± 2 1%), radionuclide purity and retardation factor (R(f) = 10.0 ± 0.1 cm) of (90)Y(3+) recovered in the eluate. Ultimately, the sorbent packed column also presented high stability for reusing 2-3 cycles without drop in its efficiency (±5%) towards Y(3+) uptake and relative chemical recovery. A proposed flow sheet describing the analytical procedures for the separation of (90)Y(3+) from (90)Sr(2+) using chelating Chelex 100 (anion exchange) packed column is also included.