My company does stable isotopic breath CO2 measurements. (13CO2/12CO2).  We collect
samples in Monoject vacutainer tubes, and they seem stable for over one year.  Do
not know if that is acceptable, but it may be worth a try.

Keisuke Koba wrote:

> Dear all:
> We need containers for sampling and storage of CO2 gas for isotopic measurement.
> It will take a couple of days to bring the gas samplers from our site and
> undertake the isotopic measurement.
> Does anyone have comments about the materials of the gas samplers, and about
> the procedure for gas sampling?
> Previously, topic on materials of stopcocks is discussed on this mailing
> list.  Then we would like to know if this effect
> is detectable in carbon isotopic measurements of CO2 gas (several hundred
> ppm) stored for a week.
> Any comments are welcomed.
>
> Thanks in advance.
> Keisuke
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> Keisuke Koba (Assistant professor)
> Environmental informatics, Biosphere Informatics
> Department of Social Informatics, Graduate School of Informatics,
> Kyoto University  606-8501, Japan.
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