Rapid determination of 135Cs and precise 135Cs/137Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry

For source identification, measurement of Cs-135/Cs-137 atomic ratio not only provides information apart from the detection of Cs-134 and Cs-137, but it can also overcome the application limit that measurement of the Cs-134/Cs-137 ratio has due to the short half-life of Cs-134 (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise Cs-135/Cs-137 atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable Cs-133, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure Cs-135/Cs-137 atomic ratios and Cs-135 activities in environmental samples (soil and sediment) for radiocesium source identification. (C) 2016 Elsevier B.V. All rights reserved.