SEPARATION OF RADIOACTIVE STRONTIUM FROM NATURAL SAMPLES BY MEANS OF MIXED-SOLVENT ANION-EXCHANGE

A new procedure for isolation and determination of Sr-90 in real natur al samples is presented. It consists of bringing natural samples in a soluble form suitable for separation on an ion-exchange column, separa tion of calcium from strontium by means of the anion exchanger Amberli te CG-400 and 0.25M HNO3 in methanol as eluent for calcium, and the de termination of Sr-90 using a low level beta-counter after elution with H2O, scavenging steps and SrCO3 precipitation. The method was tested with IAEA standards of natural samples with known contents of Sr-90, a nd water samples, where the concentration of Sr-90 was previously dete rmined by the standard IAEA procedure, The results obtained show that it is possible to isolate and determine low levels of Sr-90 in natural samples. The procedure is favorable because of the simple separation of radioaactive strontium without using fuming nitric acid.