Determination of radium isotopes in mineral water samples by α-spectrometry

Abstract A method for determination of low-level radium isotopes in mineral water samples by α-spectrometry has been developed. Ra-225, which is in equilibrium with its mother 229 Th, was used as a yield tracer. Radium were preconcentrated from water samples by coprecipitation with BaSO 4 and iron (III) hydroxide, isolated from uranium, thorium and iron using a Microthene tri-octyl-phosphine oxide (TOPO) chromatography column, separated from barium in a cation-exchange resin column, electrodeposited on a stainless steel disc in a medium of oxalate, and counted by α-spectrometry. The lower limits of detection of the method are 0.12 mBq l −1 for 226 Ra and 224 Ra, respectively.