Pages: 185-191

Authors:

Alberto Otero-Pazos, Alfonso Calleja-Garcia, Maria Isabel Fernandez-Ibanez, Benigno Antonio Rodriguez-Gomez, Andres Jose Pinon-Pazos, Jose Luis Calvo-Rolle

Abstract

The determination of ⁹⁰Sr in milk samples is the main objective of radiation monitoring laboratories because of its environmental importance. In this paper the concentration of activity of 39 milk samples was obtained through radiochemical separation based on selective retention of  Sr in a cationic resin (Dowex 50WX8, 50-100 mesh) and subsequent determination by a low-level proportional gas counter. The results were checked by performing the measurement of the Sr concentration by using the flame atomic absorption spectroscopy technique, to finally obtain the mass of ⁹⁰Sr. From the data obtained a statistical treatment was performed using linear regressions.  A reliable estimate of the mass of ⁹⁰Sr was obtained based on the gravimetric technique, and secondly, the counts per minute of the third measurement in the ⁹⁰Sr and ⁹⁰Y equilibrium, without having to perform the analysis. These estimates have been verified with 19 milk samples, obtaining overlapping results. The novelty of the manuscript is the possibility of determining the concentration of ⁹⁰Sr in milk samples, without the need to perform the third measurement in the equilibrium.

Key words: strontium, proportional counter, flame atomic absorption spectroscopy, linear regression, radiochemical separation

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