Analysis of Sr in environmental samples at the attogram-level by accelerator mass spectrometry

Martschini, M.*; Honda, Maki   ; Merchel, S.*; Winkler, S.*; Golser, R.*

The quantitative analysis of Sr is cumbersome and time-consuming because it is a pure -ray emitter. The detection limit of Sr by conventional accelerator mass spectrometry (AMS) methods is comparable to the typical detection limit of 3 mBq for -ray detection methods, mainly due to the interference of the isobaric Zr. The worldwide unique Ion Laser Interaction Mass Spectrometry (ILIAMS), performed at the University of Vienna, effectively removes Zr with a laser and reaction gases. Therefore, the detection limits of Sr is superior (0.1 mBq) to conventional AMS systems not equipped with such an ion-laser interaction isobaric removal system. In this study, Sr analysis in coral samples etc., an environmental sample under extreme conditions (e.g. low concentrations of Bq/g and limited sample volumes of grams), was tried. To lower the detection limit 0.1 mBq, Sr was purified (Sr carrier) from old age coral with almost no Sr contamination from atmospheric nuclear tests, chemical separation of environmental samples were conducted, and Sr was measured by AMS. The results showed that the detection limit of Sr achieved in the analysis was 0.03 mBq (Sr/Sr 510, 1/100 of the -ray detection methods). The detection limit achieved in this study corresponds to 2 ag of Sr in 1 mg of Sr target. The latest results of highly sensitive Sr analysis in small amounts of general environmental samples (coral, seawater, etc.) are mainly presented.