Application of in-house method for determinationof radium isotopes in environmental samples usingthe Liquid Scintillation counting technique

Nik Azlin Nik Ariffin, Zal Uyun Wan Mahmood, Che Abd Rahim Mohamed

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DOI: 10.4236/jasmi.2011.11001                

Abstract

A method for determination of ²²⁶Ra and ²²⁸Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by coprecipitation with BaSO₄, then purified from others radionuclide interferences using the cation column exchange (Bio-Rad AG 50 W-X4 resin with 200-400 mesh size and H+ form) and operating in warm temperature which is between 70-80^oC. Then, the Ba(Ra)SO₄ precipitate was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. The activity concentration of radium isotopes in mixture of liquid scintillation cocktails were measured using LSC after being stored for over 21 days to allow the growth of the progeny nuclides. The method has been validated with a certi-fied reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 59% - 90% and recovery was 97% and 80% for ²²⁶Ra and ²²⁸Ra, respectively. Sixteen seawater and fish flesh samples collected in Kapar coastal water have been analyzed with the developed method. The obtained radium activity concentrations in seawater were in the range of 02.08 ± 0.82 mBq/L to 3.69 ± 1.29 mBq/L for ²²⁶Ra and 6.01 ± 3.05 mBq/L to 17.07 ± 6.62 mBq/L for 228Ra. Meanwhile, the activity concentrations of ²²⁶Ra and ²²⁸Ra in fish flesh were in the range of 11.82 ± 5.23 – 16.53 ± 6.53 Bq/kg dry wt. and 43.52 ± 16.34 – 53.57 ± 19.86 Bq/kg dry wt., respectively.

Keywords

²²⁶Ra, ²²⁸Ra, Environmental Samples, Chemical Yield, Liquid Scintillation Counting

Conflicts of Interest

The authors declare no conflicts of interest.

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