Rapid determination of 90Sr in seawater using a novel porous crown-based resin and tandem quadrupole ICP-MS/MS in cool plasma and O2-He mode

Abstract

There has been an increasing need for the rapid and automated analysis of 90Sr in seawater for the purpose of radiological assessment and emergency response after the FDNPP accident. In this work, a rapid method for the determination of 90Sr in seawater was established using ICP-MS/MS with cool plasma and collision-reaction gases combined with a new porous crown-based resin separation. A nanofiltration membrane was applied to rapidly pre-treat seawater samples within 3 min and remove most of the matrix components from 500 mL to 250 mL for the first time. A comprehensive investigation was performed to study the extraction behaviors of Sr, Zr, Ge, Y and matrix elements on the new resin, showing an excellent separation efficiency (> 103) using a U-shaped resin column. Based on their different first ionization potentials, the 90Zr+ and 89Y+ interferences were completely eliminated under cool plasma conditions. The interferences of 74Ge16O+ and 88Sr were effectively suppressed by using 2 mL/min He-0.3 mL/min O2 as the collision and reaction gases in the dynamic collision/reaction cell. Combined with chemical separation, the overall decontamination factors of Zr, GeO and Y were 1.9 × 1010, 6.9 × 107 and 6.9 × 107 respectively, and 88Sr1H2+ tailing was reduced by more than 200 times compared to a conventional ICP-MS. A detection limit of 4.6 pg/L (24.0 Bq/L) for 90Sr was achieved with a sample analysis turn-around time of 6 h for a set of 12 samples. The method was validated by analyzing spiked seawater samples.