An evaluation of radium-specific, solid-phase extraction membranes

An analytical method based upon solid-phase extraction disks and applicable to the analysis of radium in aqueous samples (i.e., surface, ground, and drinking waters) is described. Radium is isolated by pulling an acidified sample aliquot through an Empore trademark Radium Rad Disk with a vacuum. The disk then may be directly assayed by the least-squares gamma-ray spectrometric method. Alternatively, the radium or daughter products may be eluted from the disk and further processed according to traditional EPA-prescribed methods. This method is efficient, safe, reliable, and potentially field deployable. Samples are easily processed in batches, and a 1-L sample may be prepared in as little as 20-30. Empore trademark Radium Rad Disks have been found to exhibit a large capacity for radium; over 74 Bq of 226Ra have been loaded onto a 25-mm disk. Quantitative recoveries of radium have been observed for sample volumes up to 3 L with a 47-mm disk