Novel ⁹⁰Sr analysis of environmental samples by Ion-Laser InterAction Mass Spectrometry

The sensitive analysis of ⁹⁰Sr with accelerator mass spectrometry (AMS) was developed to advance environmental radiology. One advantage of AMS is the ability to analyze environmental samples with ⁹⁰Sr/⁸⁸Sr atomic ratios of 10^-14 in following a simple chemical separation. Three different IAEA samples with known ⁹⁰Sr concentrations (moss-soil, animal bone, Syrian soil: 1 g each) were analyzed to assess the validity of the chemical separation and the AMS measurement. The ⁹⁰Sr measurements were conducted on the AMS system VERA combined with the Ion Laser InterAction Mass Spectrometry (ILIAMS) setup at the University of Vienna, which has excellent isobaric separation performance. The isobaric interference of ⁹⁰Zr in the ⁹⁰Sr AMS was first largely removed by chemical separation. The separation factor of Zr in two-step column chromatography with Sr resin and anion exchange resin was 10⁶. The ⁹⁰Zr remaining in the sample was effectively suppressed by ILIAMS. This procedure achieved a limit of detection <0.1 mBq in the ⁹⁰Sr AMS, which is lower than typical β-ray detection. The agreement between AMS measurements and nominal values for the ⁹⁰Sr concentrations of IAEA samples indicated that the new highly-sensitive ⁹⁰Sr analysis in the environmental samples with AMS is reliable.