Radiochemical Determination of Strontium-90

Abstract Detailed procedures have been developed for strontium-90 in foods and agricultural materials. Sr-90 must be isolated from the bulk matrix of the sample, generally by wet or dry ashing followed by chemical or ion exchange. Non-radioactive Sr is added as a carrier because of the small mass of Sr-90. Final determination is made by letting Sr-90 and yttrium-90 attain radioactive equilibrium, separating the Y-90, and measuring its activity. Yield is determined radiometrically with Sr-85 tracer. Sr-89 is determined at the same time by the same radiochemical procedures, except that the yield is determined gravimetrically.