Bestämning av 226Ra I vatten med hjälp av ICP-SFMS med 223Ra för utbytesbestämning

A method for the determination of 226Ra in water has been set up. Radium in water was separated from the sample matrix by using the solid phase extraction materials UTEVA and Sr resin. The samples were spiked with 223Ra as tracer and the chemical yield determination was performed using gamma spectrometry. The chemical yield for the method was 103(5) % (k=2). 226Ra was determined using ICP-SFMS. The detection limit for the method was 34 mBq/kg 226Ra. This detection limit is good enough for the determination of 226Ra in drinking water, as the individual dose criterion for alpha radiation is 0.1 mSv/year, which means that the 226Ra content in drinking water should be lower than 0.5 Bq/l. A quality control sample from an IAEA laboratory intercomparison has been used for validation. The results that were achieved agreed well with the reported value for the quality control sample. In this report advantages and drawbacks of the methods are discussed and some possible continuations of the project are presented.