Comparison of radium-226 separation methods based on chromatographic and extraction resins for its determination by...

Over the past century, human activities have contributed to the release of ²²⁶ Ra (t_½  = 1,600 y) in the environment, increasing the potential risks for human exposure and thus prompting scientists to monitor it. Inductively coupled plasma mass spectrometry (ICP-MS) is an alternative to alpha-spectrometry for the quantification of ²²⁶ Ra. However, the performances of radioanalytical procedures are rarely compared in a rigorous framework, which means that researchers may choose one on subjective factors or guesses. This article compares five published methods for the separation and preconcentration of ²²⁶ Ra in drinking waters based on chromatographic and extraction resins prior to its analysis by ICP-MS. We evaluated the turnaround time, generated wastes, and final cost of each protocol as the economic aspect can be an important criterion when selecting a method, particularly for sustainable environmental monitoring. Our results showed that ²²⁶ Ra was successfully separated and preconcentrated, yielding recoveries ranging between 84% and 105%. Method detection and quantification limits of respectively 2-7 fg L^-1 (0.1-0.3 mBq L^-1 ) and 6-24 fg L^-1 (0.2-0.9 mBq L^-1 ) were achieved when the separation method was coupled with ICP-MS. The turnaround times ranged between 6 and 21 hours, whereas the cost of the methods varied between 40 and 132 USD. This study highlights for the first time that methodologies recently published on the evaluation of ²²⁶ Ra levels in drinking water by ICP-MS have comparable figures of merit. Our results offer essential insights into the selection of the most suitable separation method.