Determination of low-level 135Cs and 135Cs/137Cs atomic ratios in large volume of seawater by chemical separation coupled with triple-quadrupole inductively coupled plasma mass spectrometry measurement for its oceanographic applications

Radioisotopes of cesium are powerful tracer for oceanographic studies. In this work, a novel method was developed determination ultra-low level 135Cs and 137Cs in seawater using triple-quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). Cesium pre-concentrated from up to 45 L samples ammonium molybdophosphate (AMP) adsorption, following selective leaching Sr(OH)2. The further purified interfering elements AMP-PAN cation-exchange chromatography. Sr(OH)2 found be an effective approach exchange the AMP sorbent without dissolution, which avoids problem separation huge amount NH4+ MoO42− steps. decontamination factors barium rubidium with were more than 4 × 107 800, respectively. separated measured ICP-MS/MS by employing N2O as reaction gas elimination isobaric (i.e. 135Ba 137Ba) polyatomic ions interferences. A detection limit 1.5 10−16 g L−1 achieved. concentrations Baltic Sea, Danish straits Roskilde Fjord determined identify sources 135Cs, water masses region investigated 137Cs.