Use of a Single Stronium Binding Resin in a Batch Process Followed by Elution and Precipitation of SrCO_3 for the Efficient Analysis of ~(89)Sr and ~(90)Sr in Liquid Milk

摘要

The strontium binding resin is readily prepared by mixing an aqueous acetonitrile solution of the cryptand 222 with the Dowex 50 W X 8 cation exchanger. The resulting resin removes about 96% of the strontium (Sr) directly from milk after 4 hours contact at pH 5.2, 20―25°C, and a resin to milk volume ratio of 1:50. Residual milk is washed from the resin with hot deionised water, while Ca~(2+) and Mg~(2+) ions are efficiently removed with aqueous pentasodium tripolyphosphate (0.1 mol/l). Sr is eluted with a solution of sodium chloride (2 mol/l) in dilute hydrochloric acid (1 mol/l). This eluate is adjusted to pH 12.0―12.5 and Sr precipitated as carbonate (SrCO_3). Overall yields of Sr up to about 90% can be obtained. The SrCO_3 is dissolved in toluene sulfonic acid then dispersed in a liquid scintillator for measurement by low-level liquid scintillation spectrometry. Many samples can be treated simultaneously with this method. Its applicability to the monitoring of Sr-89 and Sr-90 in milk and other liquids under routine and emergency conditions is being studied.