A rapid field extraction method for determination of radon-222 in natural waters by liquid scintillation counting

Fred W. Leaney and Andrew L. Herczeg
Limnol. Oceanogr. Methods (2006) 4:254-259

A simple and robust method for determination of ²²²Rn in natural waters is described. A 1.3-L water sample is collected in a plastic (PET) water bottle and shaken with 20 mL mineral oil scintillant for 4 minutes. Radon preferentially migrates to the mineral oil, and the 222Rn activity is determined by counting 222Rn and the shortlived daughter products ²¹⁴Po and ²¹⁸Po using an ultra-low-level LS counter via a/b separation technique. The PET method achieves a detection limit of ~3 mBq L^–1, making it an ideal method for analysis of surface water and groundwater samples.