Determination of 210Pb by measurement of 210Pb and its progenies using a liquid scintillation counter

Abstract

Lead-210 is a useful tracer in environmental studies for a wide range of applications, particularly in atmospheric research and geochronology. Liquid scintillation counting (LSC) is a commonly used measurement method for 210Pb analysis. In the present work, to increase detection efficiency, an improved LSC technique for 210Pb determination was developed. After adding lead carrier, samples were decomposed with mineral acid in closed digestion vessels. Using extraction chromatography with Sr resin, 210Pb was selectively separated and precipitated as lead oxalate. Following re-dissolution, the solution was mixed with a scintillation cocktail and measured by a liquid scintillation counter. In this study, all the spectral regions with peaks of 210Pb, 210Bi, and 210Po were used to calculate the activity of 210Pb; this is in contrast to the existing method, which divides the spectra into three regions according to energy level, and then selects only the 210Pb region. The method in this study also addresses a procedure for correcting blank values to account for 210Pb activity in the Pb2+ carrier. This measurement technique, using the spectral regions of 210Pb, 210Bi, and 210Po, exhibited more than twice the detection efficiency of the conventional method using only the 210Pb spectrum region. This measurement technique is expected to be a useful method for 210Pb analysis of environmental samples that show low activity, and when sample amounts are limited.