Validation of <sup>226</sup>Ra and <sup>228</sup>Ra Measurements in Water Samples Using Gamma Spectrometric Analysis
- 1 Nuclear and Radiological Regulatory Authority, Cairo, Egypt
- 2 Nuclear and Radiological Regulatory Authority, Cairo, Egypt
Abstract
Radium isotopes can be analyzed by different analytical methods based on gamma spectrometric measurements or alpha spectrometry. An improved method was developed to determine radium isotopes from water using gamma spectrometry after radiochemical separation. The Radium was selectively extracted from acidified samples using co-precipitation procedure with iron hydroxide and followed by precipitation of radium as radium sulphate Ba(Ra)SO 4 . The precipitate Ba(Ra)SO 4 was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. 226 Ra and 228 Ra activities were measured using low-background gamma spectrometry in water samples. Radium was pre-concentrated from environmental samples by co-precipitation with BaSO 4 . The amounts of 226 Ra and 228 Ra on the sample were obtained by gamma-ray spectrometry for the 351 keV γ -ray from 214 Pb and for the 911 keV γ -ray from 228 Ac, both in radioactive equilibrium with precursors, respectively. The accuracy, selectivity, traceability, applicability and Minimum Detectable Activity (MDA) of the technique w ere discussed. Also, the effect of physical and chemical characteristics of the water samples such as TDS, pH, soluble species, sulphate and bicarbonate that effect on the radium determination were taking into consideration. The method has been validated with a certified reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 70% - 90% and recovery was 97% and 80% for 226 Ra and 228 Ra, respectively .
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