On Fri, 22 Jun 2001 08:43:07 -0400 Bill Showers <[log in to unmask]>
wrote:

> 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

Hi Bill,

Are you using Silvered Colbalt Oxide at the bottom of your combustion
column?
Are you sure your water trap material (Magnesium Perchlorate for us) is
fresh?

Tom


Tom Maddox, Project Coordinator
Isotope Laboratory
Institute of Ecology, UGA
Phone (706)542-6023
WebSite http://www.uga.edu/~sisbl/