Hannover 2013 – wissenschaftliches Programm
MS 7.5: Vortrag
Mittwoch, 20. März 2013, 15:15–15:30, F 442
Some pitfalls in chemical sample preparation for accelerator mass spectrometry — •Silke Merchel — HZDR, Dresden, Germany
Sophisticated sample preparation including the determination of stable nuclides are an essential prerequisite for high-accuracy accelerator mass spectrometry (AMS) data. Improvements in the low-level regime already paid back , however, some pitfalls still exist or are (re-) appearing due to recent developments: 1.) As most samples prepared for 10Be-AMS need the addition of 9Be in the form of a liquid solution of known 9Be-concentration and commercial solutions contain too much 10Be, solutions from minerals originating from deep mines have been established. Special attention has recently been paid to the preparation of such a 9Be-carrier by the determination of the 9Be-value by an interlaboratory comparison. It could be shown that deviations between different labs exist, thus, it is strongly advised to have such solutions analysed at more than a single lab to prevent incorrect 10Be-results. 2.) In our approach to analyse as many radionuclides as possible in a single meteorite sample, small changes in the established chemical separation  have been tested. Though, the secondary formation of partially insoluble compounds of Mg and Al by the pressure digestion is strongly influenced, thus, yielding to too low 27Al-results in the taken aliquot and overall incorrect 26Al-results. Ackn.: DREAMS-team and colleagues performing 9Be- and 27Al-measurements (BAM, GFZ, HZDR, CEREGE, TUBAF, U Cologne, VKTA). Ref.:  NIMB 266 (2008) 4921.  Radiochim. Acta 84 (1999) 215.