Purification of 89Zr by Hydroxamate-Based Resins

In the preparation of 89Zr using a cyclotron to bombard a 89Y solid target, trace metal impurities such as Fe, Al, Zn, and Mg, along with unreacted 89Y, are present. Separation and purification are necessary for application in 89Zr-labeled radiopharmaceuticals. This study conducted the following work: the static distribution coefficients of Zr4+, Y3+, Fe3+, Mg2+, Zn2+ and Al3+ on hydroxamate-based resin were measured in hydrochloric acid and oxalic acid systems. The dynamic adsorption rates of these metal ions on the resin column were measured in hydrochloric acid. The breakthrough curves of Zr4+ in the hydroxamate-based resin were determined in hydrochloric acid. The elution of Zr4+ and Fe3+ from the resin using oxalic acid as an eluent was measured. The purification process conditions were validated using ZrCl4 simulated solution and trace amounts of 89Zr4+. The hydroxamate-based resin does not adsorb Y3+, Al3+, Zn2+, or Mg2+ in HCl. In 2.0 mol/L to 4.0 mol/L HCl solution, the adsorption of Fe3+ is poor, while the adsorption of Zr4+ is good in 2.0 mol/L to 6.0 mol/L HCl solution. The hydroxamate-based resin hardly adsorbs Zr4+ in oxalic acid solutions above 0.05 mol/L, and its adsorption capacity for Fe3+ first increases and then decreases with higher oxalic acid concentrations, reaching the strongest capacity at 0.5 mol/L. Zr4+ is adsorbed by the hydroxamate-based resin column in 2.0 mol/L to 6.0 mol/L HCl solution, with an adsorption rate exceeding 95%. As the HCl concentration increases to 8.0 mol/L, the adsorption rate drops to 61.42%. Y3+, Al3+, and Mg2+ are hardly adsorbed in 2.0 mol/L to 8.0 mol/L HCl. Fe3+ shows negligible adsorption in 2.0 mol/L to 4.0 mol/L HCl, but the adsorption rate increases to 15.69% at 8.0 mol/L HCl. Using 200 mg of hydroxamate-based resin meets the adsorption capacity requirements for Zr4+ in the purification of 89ZrCl4 solution. During Zr purification, a 0.10 mol/L to 1.00 mol/L oxalic acid solution can be chosen for elution, but it is difficult to wash off Fe with this solution. 89Zr mainly concentrates in the elution volume of 400 μL to 1200 μL, with a total recovery rate exceeding 85%. Y3+, Al3+, Zn2+, and Fe3+ remain in the adsorption effluent and washing solution, with no impurities adsorbed on the resin column. Zr is almost completely adsorbed on the resin column, and the elution liquid can effectively wash out Zr, with no overlap between Zr elution peaks and impurity peaks. Using hydroxamate-based resin columns, an efficient and rapid method is established for separating and purifying 89Zr from Y targets after cyclotron bombardment. Solutions containing Zr4+, Y3+, Fe3+, Al3+, Zn2+, and Mg2+ pass through the hydroxamate-based resin columns. Then, 2.0 mol/L HCl and deionized water are used sequentially to wash the columns, and finally, Zr4+ adsorbed on the resin is eluted with 0.50 mol/L oxalic acid, resulting in a purified oxalic zirconium solution. Studies with stable isotopes and 89Zr tracers indicate that the process for purifying 89ZrCl4 solution using hydroxamate-based resin is feasible, and the resin effectively removes Mg2+, Fe3+, Y3+, Al3+, and Zn2+ from the 89ZrCl4 solution.