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

- First time a sequential method for Sr-90 and Po-210 was developed.
- A low quantification limit was obtained combining lyophilisation and acid leaching.
- The method was applied to seafood samples.
- The method was fully validated through certified reference materials and intercomparison exercise.
- Good chemical yields were obtained.

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 2.0 Bq kg−1 for 90Sr and 210Po, respectively. The proposed radiochemical separation can be completed within 2 days 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.