Rapid radiochemical separation of radium from environmental samples using ion-exchanger Zeokarb-225

A rapid radiochemical method has been developed for the separation of radium in the presence of excess calcium from environmental samples such as spring waters and marine sediments. Radium is preconcentrated by co-precipitation as carbonates along with other alkaline earths. Subsequently, most of the alkaline earths are complexed with EDTA at pH 7.5 and the solution is passed through a column of Zeokarb-225 (NH ₄ ⁺ ). Radium, along with traces of calcium, is sorbed on the exchanger. Radium is desorbed with 2N HNO₃ and finally coprecipitated with 400 μg of barium as isulfate. The alphas of²²⁶Ra are counted in a silicon surface barrier detector and²²⁸Ra betas are counted in an end-window GM Counter.