Validation of procedure for the determinations and quantification of Sr-90 by liquid scintillation and Cerenkov in milk powder samples

An analytical method was described in the Analytical Quality in Nuclear Applications series No. 27- 2013 to determine Sr-90 in milk powder samples, by liquid scintillation at the Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares (CICANUM). Method that was used for development of the separation of Sr-90 consisted in chromatographic columns previously treated to eliminate interferences and separate Strontium and then analyzed by a Liquid Scintillation. The methodology to the separation chemical was established to determinate Sr-90 in four different powder milk samples (whole milk, partially skimmed, lactose reduced and skimmed milk) based in the Analytical Quality in Nuclear Applications Serie No 27-2013 methodology, adapting it to the capacities of the Alpha and Beta laboratory (CICANUM). The Cerenkov mode has been unnecessary for the determination of Sr-90, because the equation considers the growth of yttrium in the final activity. The Cerenkov mode has simply functioned as a control in a nuclear disaster or nuclear test. The method has been carried out in Costa Rica and especially at CICANUM, because this research center has the capabilities to develop this type of work, the methodology was successfully validated, this procedure takes three days to prepare a sample, therefore that this methodology needs to contemplate a decrease over time. The duration of the methodology could have been reduced, if the conditions of the columns had been improved