The aim of this work is the application of well-known adsorbents for the separation of ⁹⁰Sr, ⁹⁰Y, and ⁹⁰Zr radionuclides. Three basic types of adsorbents have been studied: Dowex HCR S/S cation exchange resin, Dowex 1x8 anion exchange resin, and titanium dioxide with a chemically modified surface. The most effective adsorbent for the separation of strontium, yttrium, and zirconium ions was titanium dioxide with a chemically modified surface. This adsorbent selectively absorbs zirconium cations against the background of excess strontium and yttrium ions. The separation takes place in 2% HNO₃ at initial concentrations of the studied cations 10 ng/ml and 100 ng/ml. Analysis of the initial mixture and the mixture after separation was conducted using ICP-MS “Element-2” with argon plasma. Age of ⁹⁰Sr-⁹⁰Y β^- -source (approximately 30.2 years old) was measured using the method of the chemical separation of ⁹⁰Sr and ⁹⁰Zr by the titanium dioxide and following calculation of the ⁹⁰Zr/⁹⁰Sr ratio. The age of ⁹⁰Sr-⁹⁰Y β ^- -source was calculated as 31.9 ±1 year. The combination of liquid scintillation counting of ⁹⁰Sr and ICP-MS analysis was proposed as an alternative method of determination of the ⁹⁰Zr/ ⁹⁰Sr ratio. It was shown, that both methods provide similar results in radio chronometry of ⁹⁰Sr-contained compound, i.e. age-dating of liquid ⁹⁰Sr-⁹⁰Y β^- -source, and could validate each other.

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