A sensitive and accurate method for determination of radium isotopes in environmental samples by alpha-spectrometry

A sensitive and accurate method for determination of radium isotopes in water and soil samples by alpha-spectrometry has been developed. Ra-225, which is in equilibrium with its mother 229Th, was used as a yield tracer. Radium in water samples was preconcentrated by coprecipitation with BaSO4 and iron (III) hydroxide at pH 8-9 using ammonia solution, isolated from uranium, thorium and iron using a Microthene-TOPO chromatography column at 8 M HCl, separated from barium in a cation-exchange resin column using 0.05 M 1,2-cyclo hexylene- dinitrilo-tetraacetic acid monohydrate at pH 8.5 as an eluant, electrodeposited on a stainless steel disc in a medium of 0.17 M (NH4)2C2O4 at pH 2.6 and current density of 400 mA cm-2, and counted by α-spectrometry. Radium in soil samples was fused with Na2CO3 and Na2O2 at 600 degree C, leached with HNO3, HCl and HF, and. preconcentrated by coprecipitation with BaSO4 at pH 3. The procedure for further separation, purification electrodeposition and measurement of radium in soil samples was same as that for water samples.