Determination of 90Sr traces in medical 90Y after separation on DGA column

A new analytical procedure for 90Sr determination in freshly milked 90Y from a 90Sr/90Y generator is described. To a solution containing 125 mg of Sr a 200 to 400 MBq sample of 90Y is added and strontium is separated from 90Y using DGA column of 1 mL volume. 90Sr is recovered in a yield close to 100% and counted in a liquid scintillation spectrometer (LSC). The separated strontium is slightly contaminated with 90Y in the range from 7 to 19% of 90Sr activity. The separation and counting can be completed within 30 min. The detection limit in 900 s counting time is equal to about 0.2 Bq. This corresponds to 90Sr/90Y activity ratio of 10−8 level.