New method for radiochemical determination of strontium 89 and strontium 90

Radiochemical procedures for qualitative and quantitative determination of the radionuclides 89Sr and 90Sr in various substances are described. Principally the method is based on strontium carbonate precipitation and the procedure consists of eight analysis steps: preliminary sample processing and Ca-determination; sample dissolving and filtration; addition of carriers and anti-carriers; separation of strontium from barium; precipitation of the alkali-earth elements; separation of strontium from calcium; chemical yield determination and preparing of samples for radiometry and radiometry and calculation of the radionuclides content. The separation of strontium from calcium is achieved by titration with ZnO in presence of alkalified solution of EDTA (ethilenediaminetetraacetic acid). Samples of the final precipitation consisting of non-hydroscopic SrCO3 have been submitted to beta radiation measurements. The absolute activity of each sample is determined by comparison of its count rate to the count rate of proper local 90Sr-standard measured at the same geometry. The effectiveness of the new carbonate method has been verified by testing it for determination of 90Sr in shells of the snail Helix pomatia. Its advantages over the nitric acid method and both sulfate and oxalate techniques are discussed