A Novel Method for determination of 90Sr using Thermal Ionization Mass Spectrometry

Accurate and rapid determination of 90Sr in environmental samples is a challenge after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Measurement of 90Sr using mass spectrometry instruments is faster than radiometric counting methods.Thermal ionization mass spectrometry is one of the most reliable techniques for high precision and accurate measurement of stable Sr isotopic ratios. In this work, a new method for 90Sr analysis will be presented using Isotopx TIMS. Standard Sr solution (NIST-987) with a known concentration of 90Sr was gravimetrically prepared for 90Sr/88Sr isotopic ratio determination. Abundance sensitivity for 90Sr/88Sr ratio was 2.3×10-10. This method is very sensitive for 90Sr detection and detection limit is about 1 mBk (0.2 fg) and has been measured using Daly ion counting system in combination with Faraday cup detectors. During the 90Sr measurement, 90Zr isobaric interference was negligible and extraction chromatography resins (Sr resin) was used for chemical separation. Analytical method of validation was established with wild berry (IRMM-426) and lake sediment (NIST-4354) certified reference materials.Goldschmidt 201