Intricacies of the Determination of the Radiochemical Purity of 68Ga Preparations: Possibility of Sorption of Ionic 68Ga Species on Reversed-Phase Columns

摘要： The results of studying 68Ga radiopharmaceuticals using various TLC and HPLC procedures are compared. The data obtained reliably show that a part of 68Ga ionic species are irreversibly (under definite conditions) sorbed onto chromatographic columns packed with С18 reversed phase. The loss of 68Ga ionic species in the analysis can reach 90%. The 68Ga loss increases with an increase in pH of the preparation. At pH 2.5–3.0, the total loss of 68Ga ionic species on the chromatographic column does not exceed 15%. At pH 4.0, it is 65 ± 7% on the average, and at pH 6.0 it reaches 87 ± 8%. This effect should be taken into account in analysis of any 68Ga radiopharmaceuticals.