Isotopers,

This is an interesting discussion for our lab.  We are fuming bivalve
shells in silver boats with HCL, and then drying them and analyzing the
organic N-15 and C-13 with EA CF-IRMS.  We find that the first 20-30
samples run well, then at the end of the run we start to see tailing with
the N-15 measurments.  We just have a water trap behind the combustion and
reduction tubes.  We want to do a dual measurement of N-15 & C-13, so we
need a trap that will not remove CO2, but will nail any residual "acid gas"
from the decalcified samples, any suggestions other than carbosorb or LiOH?

Thanks,
Bill

At 12:32 PM 6/22/2001 +1200, you wrote:
>Ernst,
>Do you use the CO2 trap during analysis of acid traps? Any acid gas should
>be removed on contact with LiOH and in my experience prevents even a slight
>SO2 peak from appearing.
>R Van Hale

William J. Showers
Dept of Marine, Earth & Atm Sciences
North Carolina State University
Raleigh NC 27695

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