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 is a growing demand 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 90Sr determination 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-concentrate seawater samples from 500 mL to ~250 mL within 3 minutes and remove major matrix components 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 the excellent separation efficiency (> 103) using a U-shaped resin column. Based on their different the first ionization potentials, the interferences of 90Zr+ and 89Y+ were completely eliminated under cool plasma conditions. The interference signals of 74Ge16O+ and 88Sr1H2+ were effectively suppressed by using 2 mL/min He−0.3 mL/min O2 as the collision and reaction gases in DRC of ICP-MS/MS. Combined with chemical separation, the overall elimination efficiency of Zr, GeO and Y reached 1.85×1010, 2.06×106 and 2.30×109 respectively, and the removal efficiency of 88Sr1H2+ interference was improved by > 200 times compared to the conventional ICP-MS. The detection limit of 1.11 pg/L (5.62 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.

Keywords: Strontium-90, porous crown-based resin, ICP-MS/MS, cool plasma, O2-He mode, seawater sample