Determination of Sn(II) in technetium cold kits by voltammetry at the hanging mercury drop electrode (HMDE) and relevant radiopharmaceutical applications.

A novel approach for the determination of the stannous content in cold kits for labelling with 99mTc is described. The method is based on differential pulse polarography on the hanging mercury drop electrode in a methanol/water/perchloric acid mixture and is easy to perform. Examples for the determination of tin(II) in fractionated technetium cold kits are shown. The stability of tin(II) in solution was mainly dependent on the storage temperature and the kit composition. The low stability of stannous ions under certain conditions was shown to be the main reason for low radiochemical purity. Limits and dangers of fractionating kits are discussed and related to content and instability of tin(II).