> Date:          Thu, 5 Aug 1999 11:34:41 +0100
> Reply-to:      Stable Isotope Geochemistry <[log in to unmask]>
> From:          Nick Ostle <[log in to unmask]>
> Subject:       Re: 13C18O2
> To:            [log in to unmask]

> ISOGEOCHEMISTS,
>
> The research that I am involved in requires the use of both  C and O
> enriched isotopes in the same tracer studies and I need to be sure
> that I can correctly attribute values to 13C/12C and 18O/16O in CO2.
> Manufacturers suggest that their instruments can do this by using the
> mz 46/44 ratio. However when both C and O of CO2 are enriched this is
> not always possible as the Craig 18O correction is designed for
> near-natural abundance levels. Any ideas?
>
> nick
>
Hi Nick,
I spose that you should follow the way like in meteorite studies,
i.e. both del-18O and del-17O shuld be determined on O2 gas ,
then del-13C on CO2 gas on the basis of 17O correction to
peak 45.

Greetings,
                Stan
>
>
>                      Nick Ostle
>       Institute of Terrestrial Ecology
>                 ITE- Merlewood
>              Grange-Over-Sands
>               Cumbria, LA11 6JU
>                      England
>
>            e-mail: [log in to unmask]
>         tel: ++44 (0)15395 32264
>         fax: ++44(0)015395 34705
>

==============================
Professor Dr. Stanislaw Halas
Mass Spectrometry Laboratory
Maria Curie - Sklodowska University
20-031 Lublin, POLAND
tel: (48 81) 537 6275    fax: (48 81) 533 3669