Entwicklung von Methoden zur selektiven Trennung von Scandium, Zirkonium und Zinn für radiopharmazeutische Anwendungen

The subject of the present work is the development of fast and highly selective methods for the separation and purification of scandium, zirconium and tin radionuclides from potential target materials for use in nuclear medicine. A number of selected resins (TrisKem International) were first characterized with respect to their extraction behaviour towards a large number of cations. Characterization studies were performed in batch experiments by determination of weight distribution ratios Dw and further the influence of interferences on the uptake of these elements was evaluated. Weight distribution ratios were determined in different acids and acid concentrations with main focus on scandium, tin or zirconium. The interference of macro amounts of Calcium and Ti on the Sc extraction was evaluated as well as the interference of macro amounts of Y on the Zr extraction. Best suited uptake conditions were found for Scandium on DGA were determined to be 2.5 M HNO3 for Ti-Targets and 0.1 M HNO3 for Calcium-Targets. Otherwise it is also possible to extract Sc with TRU Resin. High uptakes were obtained at 2.5 M HNO3 for simulated Ti- and Calcium-targets. Separation methods were developed using elution studies; employed conditions were chosen according to parameters evaluated in the batch-experiment. The developed methods allowed separating Sc very rapidly in high purity very rapidly from Ti- or Calcium-targets. For Zr a separation method based on UTEVA Resin has been developed. Following results of batch experiments simulated Y-target solution were loaded onto a UTEVA resin column from 6 M HNO3; the elution of Zr could be performed in 0.01 M oxalic acid. Decontamination factors in the order of 10^4-10^5 could be obtained applying the developed method; the method thus allowed separating Zr in a high purity. Initial testing of a method for the separation of Sn from Cd targets based on the use of TBP Resin showed that the TBP resin seems to have a goof potential for this use. Another part of this work is dealing with the preparation and application of an extraction chromatographic resin based on the use of multi-walled nanotubes. It could be shown that resins based on nanotubes do have some interesting properties; but it could also be shown that of such resins have some distinct disadvantages especially with respect to their practical use. Packing a column with nanotubes based materials is far more challenging then packing a column with classical resin. Achieving flow rates sufficiently high for their foreseen use turned out to be difficult to achieve.