A sequential determination of ⁹⁰Sr and ²¹⁰Po in food samples

The latest EU Council Regulation 2016/52/Euratom updates the emergency limits on radionuclides in foods including ²¹⁰Po and ⁹⁰Sr, two of the most important radionuclides for radiological dose from the ingestion pathway. A novel and straightforward method has been developed for sequential determination of ⁹⁰Sr and ²¹⁰Po in food samples using ultra low-level liquid scintillation counting and alpha-particle spectrometry. For ⁹⁰Sr analysis, the method makes use of stable strontium as yield tracer, and ²¹⁰Po is determined through self-deposition using ²⁰⁹Po as a yield tracer. The quantification limit for this method is 25.0 and 2.0Bqkg^-1 for ⁹⁰Sr and ²¹⁰Po, respectively. The proposed radiochemical separation can be completed within 2days for a batch of 12 samples. The radiochemical procedure was validated by its application for the measurement of IAEA certified reference materials, and through participation in a national intercomparison exercise. Results are also presented in seafood from the Mediterranean coast.