SCINTILLATION EMANOMETRIC DETERMINATION OF RADIUM-226 IN WATERS USING A NEW METHOD OF RADIUM PRECONCENTRATION

A modified method of scintillation emanometry for radium determination is described which uses a simple and effective preconcentration of dissolved radium by coprecipitation with a ternary complex of calcium phosphomolybdate and polyethylene glycol. After dissolution of the voluminous precipitate in an alkaline solution of ethylenediamine-tetraacetic acid and deemanation of radon by a simplified procedure, the activity of radon is measured in a scintillation cell. The accuracy and precision of the method are very good as shown by determination of radium-226 in standard solutions and in natural water samples distributed by IAEA in the frame of interlaboratory comparison program. Easy construction of a simple scintillation cell is described, yielding cells with reproducible parameters and sufficient sensitivity for radium analysis in natural waters.