The dimensions of an ascarite trap will depend on what
you are using it for, in particular the amount of CO2
to be removed. I used an Ascarite trap sucessfully to
remove >99.9% of the CO2 from 500ml-30L air samples in
the analysis of 13C of NMHCs using CF-IRMS. The trap
was made using 20cmx 3/8" (or 30cm x 1/2") stainless
steel tubing filled with Ascarite II, held at 80oC
with a sample flow of 100 ml/min. The trap was
conditioned prior to use by holding it at 80oC for at
least 8 hours under helium flow, and then prior to
each sample by flowing the sample through it as you
would condition the lines. If your samples are
particularly dry you may
need an additional condition step whereby you pass
humidified He through
it to maintain removal efficiency. A similar method is
described by Rudolph et al, GRL 24 (6): 659-662 MAR 15
1997. Good luck!
Miller Research Fellow
Ecosystem Science Dept, ESPM
University of California at Berkeley
ph +1 510 643 6910
fax +1 510 643 5098
--- Tiziano Boschetti <[log in to unmask]>
> Dear Isogeochemists,
> Can anybody tell me what's the correct dimension
> and preparation of an
> "ascarite trap" on CF-IRMS analysis?
> Thank you.
> Best regards.
> Tiziano Boschetti
> Dipartimento di Scienze della Terra - UniversitÓ di
> (Earth Sciences Department - University of Parma)
> Parco Area delle Scienze 157a
> 43100 Parma, ITALY
> Fax: +39-(0)521-905305
> e-mail1: [log in to unmask]
> e-mail2: [log in to unmask]
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