Journal of Radioanalytical and Nuclear Chemistry

, 282:309

First online:

Low level detection of 135Cs and 137Cs in environmental samples by ICP-MS

  • M. LiezersAffiliated withPacific Northwest National Laboratory Email author 
  • , O. T. FarmerIIIAffiliated withPacific Northwest National Laboratory
  • , M. L. ThomasAffiliated withPacific Northwest National Laboratory

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The measurement of fission product cesium isotopes 135Cs and 137Cs at low femtogram (fg) 10−15 levels in ground water by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is reported. To eliminate the natural barium isobaric interference on the cesium isotopes, in-line chromatographic separation of the cesium from barium was performed followed by high sensitivity ICP-MS analysis. A high efficiency desolvating nebulizer system was employed to maximize ICP-MS sensitivity ~10 cps/fg. The three sigma detection limit for 135Cs was 2 fg/mL (0.1 μBq/mL) and for 137Cs 0.9 fg/mL (0.0027 Bq/mL) measured from the standard with analysis time of less than 30 min/sample. Cesium detection and 135/137 isotope ratio measurement at very low femtogram levels using this method in a spiked ground water matrix is also demonstrated.


Isotope ratio Cesium Environmental Chromatography Gamma spectrometry Quadrupole ICP-MS