Determination of 226Ra in mineral waters by high-resolution inductively coupled plasma mass spectrometry after sample preparation by cation exchange

Ra-226 in mineral waters was determined by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). The analytical result was compared with that by liquid scintillation counting. A cation exchange technique was used for separation of Ra-226 from matrix elements in the water samples. Analyte recovery efficiency was better than 97% and matrix separation efficiency was higher than 99% for Ca, the major matrix element. The method detection limit of 0.01 pg L-1 was achieved which was much lower than the United States Environmental Protection Agency required detection limit of 1 pg L-1. Ra-226 concentrations in several Korean mineral waters are presented.