²¹⁰Po and uranium sequential analysis by extractive liquid scintillation spectrometry

²¹⁰Po (t_1/2 = 138 days) is a decay product in the ²³⁸U decay series and widely distributed in the earth's crust and environment. Natural concentration of polonium in environment can be enhanced due to human activity and contributes around 8% to internal dose to human. The most widely used technique is the spontaneous deposition of Po on a silver disc but is subject to interferences from oxidants, organic materials, and other matrix elements that also deposit on the silver disc. These interferences can be removed by co-precipitation of Po and it's chemical separation from interfering radionuclides and matrix elements. Extractive scintillation cocktails, POLEX, TOPO and TNOA have been reported for ²¹⁰Po analysis from groundwater samples, but could not be validated due to co-extraction of uranium from real ground waters. In the present study, Polonium separation methodology using extractive agents 75 g L^-1 HDEHP and TOPO in toluene scintillator, followed by counting using liquid scintillation spectrometry was optimized and validated using various types of materials, including IAEA certified reference material viz., IAEA-385: Irish Sea sediment and IAEA-447: Moss-soil.