Inorganic ion exchange materials for the separation of ⁹⁰Y from ⁹⁰Sr include clinoptilolite, potassium titanosilicate pharmacosiderite, sodium titanosilicate and sodium nonatitanate. These materials are suitable for making a ⁹⁰Y generator that contains ⁹⁰Sr immobilized on an ion exchange column of the materials. The materials have a very high selectivity for ⁹⁰Sr, a very low selectivity for ⁹⁰Y, good radiation and thermal stability, low toxicity, fast reaction kinetics, and can be readily and reproducibly synthesized. A method is thus provided for eluting ⁹⁰Y from the ion exchange material with an aqueous solution to obtain a carrier-free solution of ⁹⁰Y.