hrvatski

Brza metoda za određivanje radioaktivnog stroncija u prirodnim uzorcima = Rapid method for the radioactive strontium determlnation in natural samples

Radioactive strontium isotopes belong to the group of isotopes that are very dangerous for human health. Therefore radioactive strontium is regularly determined in natural samples. When determining strontium isotopes in natural samples, it is necessary to isolate strontium from the sample because strontium isotopes are pure ß-emitters. As natural samples contain much more calcium and sodium than strontium it is necessary to isolate a small quantity of strontium from large sample with simultaneous separation of calcium and other interfering elements. For this purpose an elegant method based on ion exchange chromatography has been developed. Namely, examinations with model system have shown that strontium may be separated from calcium on the column filled with anion exchanger and the mixture of the methanol and nitric acid as eluent. It was also shown that yttrium does not separated from strontium but elutes almost simultaneously with it. Yttrium may be separated from strontium on the column filled with cation exchanger DOWEX 5Ox8 and nitric acid as eluent. According to the above examinations, the procedure of isolation of strontium and yttrium from natural sample has been created (on assumption that ?90Sr and ?90Y in secular equilibrium in sample). Strontium and yttrium have been isolated from natural sample (standard IAEA A-7) on the column fille?d ?with the exchanger AMBERLITE CG-400 and the mixture of methanol and nitric acid as eluent. Strontium and yttrium have been separated on the column with cation exchanger. 90lSr has been determined through 90Y by counting the solid yttrium oxalate immediately upon isolation and separation from strontium. 90Sr has also been deterimined by counting 90Sr-?90Y in secular equilibrium after 15 days. The obtained results of determination of 90Sr through 90Y and through secular equilibrium 90Sr-90Y correspond to the declared values of standard.

Sr-90; separacija; ionski izmjenivač; prirodni uzorci

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