The theranostic pair 44Sc and 47Sc have garnered interest in the PET imaging and treatment of various diseases. [1] 44Sc is produced either by the decay of 44Ti (which is produced by proton irradiation of 45Sc targets) or directly by the cyclotron irradiation of 44Ca targets. 47Sc is produced by the irradiation of Ti targets. Therefore, the selective separation of Ti from large masses of Sc and the separation of Sc from large masses of Ti are important separations for the production of 44Sc and 47Sc.

Following dissolution of Sc targets with concentrated HCl, 44Ti may be selectively extracted from large masses of Sc target material using a column of 2-ethyl-1-hexanol adsorbed on an inert polymeric support. Following rinses with concentrated HCl, the Ti may be recovered with 0.05M HCl-0.05M oxalic acid. Passing the collected Ti eluate through a column of strong base anion exchange resin provides additional Sc purification and removal of any leached 2-ethyl-1-hexanol. The 44Ti can then be recovered from the anion exchange resin in 1-4M HCl.

Following dissolution of Ti targets with concentrated HCl, 47Sc can be selectively extracted with DGA resin. Rinses with HCl and HNO3 remove Ti and Fe impurities, and Sc can be recovered in high purity with dilute HCl. DGA resin is one of the most stable EXC materials in regards to extractant leach. So, any additional separations are primarily geared toward removal of additional metal ion impurities. The 47Sc in dilute HCl can be acidified to 1M HNO3 or 6M HCl and further purified on a second cartridge of DGA resin.

While DGA is very frequently employed to separate Sc from irradiated Ti targets UTEVA is often preferably used for the separation of Sc isotopes from Ca targets [2,3]. Sc is very strongly retained on UTEVA even in presence of large amounts of Ca and is efficiently separated from yttrium. The latter point is of importance as the Ca target material may contain trace Sr that may result in the production of Y isotopes. The Ca targets are typically dissolved in concentrated HCl (e.g 10M HCl) and directly loaded onto a UTEVA column. After rinsing the column with 10M HCl the Sc may be recovered in a small volume of water in yields typically >80% and of purity suitable for labelling.


[1] Vyas, C.K., Park, J.H., Yang, S.D., 2016. Application of extraction chromatographic techniques for separation and purification of emerging radiometals 44/47Sc and 64/67Cu, Journal of Radiopharmaceuticals and Molecular Probes, 2(2), 84-95.

[2] Szkliniarz, M. Sitarz, R. Walczak, J. Jastrzębski, A.  Bilewicz. J.  Choiński, A. Jakubowski, A. Majkowska, A. Stolarz, A. Trzcińska, W. Zipper.  Production of medical Sc radioisotopes with an alpha particle beam. Applied Radiation and Isotopes, 118, 2016, 182-189

[3] H.F. Valdovinos, R. Hernandez, T.E. Barnhart, S. Graves, W.Cai, R.J. Nickles. Separation of cyclotron-produced 44Sc from a natural calcium target using a dipentyl pentylphosphonate functionalized extraction resin. Applied Radiation and Isotopes, 95,  2015, 23-29