A purification method is developed to determine 90Sr in radioactive waste. A separation based on Sr-resin® with a pretreatment using TRU-resin® provides satisfactory Sr recovery yields before the 90Sr measurement by liquid scintillation counting (LSC) regardless the analyzed samples with low or high activity level. The selectivity of the procedure is checked by measuring the 90Y ingrowth after different days of separation without waiting for secular equilibrium. In order to obtain a REACH compliant method without scintillation cocktails, a plastic scintillation resin selective for Sr is implemented on the basis of the developed protocol. The optimized method is applied successfully to representative nuclear waste including samples with high Pu content (effluents, concretes and sludges). [ABSTRACT FROM AUTHOR]