Determination of radium-226 in drinking water by alpha spectroscopy

A radiochemical procedure for determination of radium-226 (Ra-226) in drinking water was developed. The method involves concentrating radium by coprecipitation with barium sulfate; separating radium from barium and other alkaline earth metals by ion exchange; and electrodepositing radium onto stainless steel disc for radioactivity counting. The procedure requires the using a chemical yield tracer, Ra-223. Two methods for the preparation of Ra-223 from Ac-227 were studied. One method, which uses solvent extraction of radium with TTA/benzene, showed better results and took much less time in comparison to the other method which uses anion exchange, followed by co-precipitation of radium as Ba(Ra)SO{dollar}\sb4{dollar} and dissolution with DTPA (7). The results from the new analytical procedure for measuring Ra-226 in drinking water were compared with the traditional radon de-emanation method. The new procedure unfortunately showed no significant benefit over the de-emanation method