Stable Isotope Geochemistry


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Dr W Meier-Augenstein <[log in to unmask]>
Reply To:
Tue, 24 Feb 2004 08:00:09 -0000
text/plain (58 lines)
Hi Hil,

The best column (imho) for separation of permanent gases is the
CarboPLOT P7, or its latest incarnation, the CarboBOND. Either way, this
column is only available as megabore (= 0.53mm ID), so backpressure is
not as bad as for a MolSieve 5A with an ID of 0.32mm. However, this is
still a PLOT column and, hence will be sensitive to sudden changes in
pressure and will show a back pressure higher than a WCOT megabore.

Having said all that, your application is decidedly different and even a
megabore column won't be an option. You can try HayeSep A (80/100 mesh)
or HayeSep DB (100/120 mesh). A SS tube (say 30' x 1/8") packed with
either can be run at 25-30 ml/min He at a pressure setting of about 90
psi and a resolution of N2 from CO of about 1 min (at a column T of
about 160 C, give or take 20).

Hope this helps.



> -----Original Message-----
> From: Stable Isotope Geochemistry
> [mailto:[log in to unmask]] On Behalf Of Hilary Stuart-Williams
> Sent: 23 February 2004 22:45
> To: [log in to unmask]
> Subject: What GC column for CO separation?
> Could I ask what columns people are using to separate CO from
> N2 after pyrolysis?
> I am using an Alltech 5A mole sieve in a 1/4" SS tube at the
> moment and the separation is good, but I'd like to get the
> back pressure down if possible.
> Is there anything new out there (after seeing the previous
> discussion)?
> Hil
> .
> Hilary Le Q. Stuart-Williams PhD.
> Research Officer in Stable Isotopes
> Environmental Biology Group
> Research School of Biological Sciences
> Australian National University
> Canberra, ACT, Australia
> (02) 6125 2099
> Personal home: