An improved method for the separation of Bi-210 and Po-210 from Pb-210 by using solid-phase extraction disk membranes: Environmental applications

An improved method is described for the rapid separation of Bi-210 and Po-2 10 from the parent radionuclide, Pb-210, in environmental samples. After th e metals were leached from a variety of matrices, they were converted to th eir anionic chloride complexes by addition of 1 M HCl. These complexes can be separated by solid-phase extraction with disk extraction membranes impre gnated with anionic chelating particles. This separation technique takes ad vantage of the differences in sorption behavior of the chloride complexes t o strongly basic anion exchange groups. The extraction membranes can then b e counted directly for Bi-210 and Po-210. If sufficient time is allowed for ingrowth of the daughter, the concentration of the parent Pb-210 in the or iginal sample can be determined from the concentration of Bi-210. In additi on, the ratios of Bi-210/Pb-210 and Po-210/Pb-210 can be obtained by immedi ate extraction of Bi-210 followed by ingrowth of Bi-210 for a second determ ination to establish Pb-210 concentration levels. This can be accomplished easily in order to estimate the residence times of atmospheric aerosols or aqueous colloidal materials. This new technique avoids the time consuming e xtraction, precipitation, and electroplating procedures used previously and eliminates the experimental errors associated with multiple sample manipul ations.