[en] Selective adsorption of radiostrontium from nitric acid medium on a chromatographic resin material consisting of di-t-butyl cyclohexano 18 crown 6/n-octanol sorbed onto amberlite XAD-7 (particle size: 100-150μm) has been carried out. The column capacity is evaluated as ∼ 21 mg of Sr per gram of the resin material. The separation of radiostrontium from several metal ions present in environmental and biological samples viz. Li, Na, K, Mg, Ca, Al, Fe, Co, Ni, Zn and Cd has been achieved. A promising separation method for ⁹⁰Y from ⁹⁰Sr-⁹⁰Y mixture has also been developed. Nitric acid concentration has no observable effect on the elution profile of ⁹⁰Y as the entire amount of the loaded ⁹⁰Y activity can be eluted by 1.5 ml of the acid in a wide concentration range (0. 1 - 10 M). Half-life of the eluted ⁹⁰Y sample is calculated as 63.75 ± 0.40 hours by following the decay profile. Repeated elutions using 1.5 ml of 3 M HNO₃ after loading 200 μCi of ⁹⁰Sr - ⁹⁰Y revealed that the product with ∼ 98% radiochemical purity could be obtained up to the 12th run beyond which the contamination due to ⁹⁰Sr increased significantly. (author)