A FAST METHOD FOR THE DETERMINATION OF SR-90 IN LIQUID MILK BY SOLID-PHASE EXTRACTION WITH CRYPTAND-222 ON CATION-EXCHANGE RESIN

A method for determining the activity of Sr-90 in liquid milk samples that does not require the usual drying, ashing, acid leaching and prec ipitation procedures is described. Two solid phase extractants are use d, namely: cryptand 222 bound to a cation exchange resin, and Eichrome Industries' Sr.Spec Resin(R). These are applied respectively to extra ct Sr-90 from the milk and to isolate it in a form suitable for measur ement by low-level liquid scintillation counting The results of analys es of 1 liter milk samples contaminated with a known activity of Sr-90 agreed well with the expected values. It was also found that Sr.Spec Resin(R) can be regenerated and re-used several times. As the method r equires only minimal operator skill and time, many samples can be anal yzed simultaneously.