Accelerator mass spectrometry 14C determination in CO2 produced from laser decomposition of aragonite
Accelerator mass spectrometry 14C determination in CO2 produced from laser decomposition of aragonite
Date
2008-08-29
Authors
Rosenheim, Brad E.
Thorrold, Simon R.
Roberts, Mark L.
Thorrold, Simon R.
Roberts, Mark L.
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Abstract
Determination of 14C in aragonite (CaCO3) decomposed thermally to CO2
using an yttrium‐aluminum‐garnet doped neodymium laser is reported. Laser
decomposition accelerator mass spectrometer (LD‐AMS) measurements
reproduce AMS determinations of 14C from conventional reaction of aragonite
with concentrated phosphoric acid. The lack of significant differences between
these sets of measurements indicate that LD‐AMS radiocarbon dating can
overcome the significant fractionation that has been observed during stable
isotope (C and O) laser decomposition analysis of different carbonate minerals.
The laser regularly converted nearly 30% of material removed to CO2 despite
being optimized for ablation, where laser energy breaks material apart rather
than chemically altering it. These results illustrate promise for using laser
decomposition on the front‐end of AMS systems that directly measure CO2 gas.
The feasibility of such measurements depends on 1. the improvement of material
removal and/or CO2 generation efficiency of the laser decomposition system and
2. the ionization efficiency of AMS systems measuring continuously flowing
CO2.
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Author Posting. © John Wiley & Sons, 2008. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Rapid Communications in Mass Spectrometry 22 (2008): 3443-3449, doi:10.1002/rcm.3745.