Isolation of radioactive strontium from natural samples. A semi-automatic procedure

A procedure for semi-automatic isolation and determination of radioactive strontium from natural samples was developed. The method was tested by the determination of 90Sr in soil samples and the results obtained were compared to those obtained by the standard procedure. The procedure consists of leaching of strontium (and other cations as well) from soil samples with a water suspension of the cation exchanger Amberlite IR-20, the separation of strontium from other cations, e.g., potassium, calcium, sodium, barium by the anion exchangers Amberlite CG-400 or Dowex Ag 1 x 8 with 0.25M HNO3 in ethanol - methanol mixture as eluent in the apparatus specially constructed for this purpose. Determination of 90Sr was done on the low-level gas-flow β-counter and by Cherenkow counting on the liquid-scintillation counter few hours after the separation. It was shown that this procedure might be successfully applied for rapid determination of 90Sr in soil samples and other natural samples in a timesaving manner. (author)