Fig. 3.

Elution curves that describe the final separation procedure as a function of elution volume. The procedure for the separation of U, Th, and Pa was performed in 1 mL aliquots. Each mL added to the column was collected in a 20 mL LS vial containing 15 mL of Ecolite LS cocktail. In the 4 M HCl load solution, Th reaches an elution maximum (~5 mL) and returns to near background activity in ~20 mL. The final 15 mL were needed to remove residual Th in the Pa fraction observed in early experiments. The next 15 mL 4 M HCl-0.1 M HF removed Pa from the column, while U remained adsorbed. A final 5 mL 0.1 M HCl desorbed the U for collection and counting.