Introduction: 68Gallium is a positron emitter with a 68-minute half-life. Its metal properties make it suitable to label proteins with chelating agents such as tumour-seeking peptides and monoclonal antibodies. However, the gallium ions have to be in a suitable chemical form for labelling to occur. This project aimed to test whether a 68Germanium/68Gallium generator eluted with a citrate solution still requires purification and salt exchange to render the product useful. Anion exchange chromatography methods were studied to effect this.

Method: Using 67Ga-Citrate in place of 68Ga-Citrate, the citrate bond was digested with 6M HCl and applied to two types of anion exchange columns. Elution profiles were examined with varying concentrations of HCl

Results: Both anion exchange columns demonstrated good retention of gallium ions. The SAX SPEC column provided near-complete recovery of the 67Ga solution with distilled water and yielded no further gallium elution when eluted with various concentrations of HCl. The QMA column demonstrated a lower percentage elution of the 67Ga solution. Further elutions with various concentrations of HCl and water did not yield any more 67Ga extraction from the QMA resin.

Discussion: The results demonstrate that the SAX SPEC column would be more effective as a salt exchanger for gallium citrate eluates as it provided better 67Ga retention after digestion of the citrate bond higher elution of 67Ga. The issue that no further activity was eluted with HCl indicates that the citrate bond was successfully digested and the column is effective in purifying the isotope from its citrate counterpart.