A modified sampling preparation method for rapid determination of Pb-210 radioactivity in plants in China using crown ether and liquid scintillation counting of beta particles

Pb-210, a highly-toxic radionuclide, is widely distributed in environments and is commonly the target for monitoring. In this paper, a modified method for determining Pb-210 radioactivities in plants in China has been presented. The procedure involves digesting the plant samples by microwave directly, separating Pb-210 from Bi-210 and Po-210 with Sr resins, and measuring the beta particles using liquid scintillation counting (LSC). Compared to previously reported approaches, this method uses no hydrochloric acids which are restricted in China and involves no co-precipitation. The entire procedure could be finished within 1 day with a radiochemical yield of 70%. The lower limit of detection for Pb-210 was found to be 38.0 mBq/g for a counting time of 72,000 s. The method was tested using a standard solution and plant samples. LSC spectra indicate that Pb-210 is effectively stripped and the results are consistent with those obtained from the gamma-spectrometry.