Dear Uli,

For what it's worth - We haven't done an exhaustive study of natural
caffeines but we have had the chance to look at a few natural vs synthetic
products from the US, India and China.  There's no mistaking the synthetic
versions.

Sample            Carbon            Nitrogen
-----------------------------------------------------------
USA syn           -37.2               -29.7
USA nat            -27.0                 4.5

India ?               -29.7                  1.5
India nat            -29.7                  1.4
India syn            -41.6              -29.1

China ?             -33.7               -24.7
China ?             -37.9               -13.9
-----------------------------------------------------------

Samples with "?" were labelled by country of origin but not for natural vs
synthetic. If you are only interested in the natural products, the
indication is that there may be some significant variations out there.

Best regards,
Richard Anderson
----------------------------------------------------------------
    Coastal Science Laboratories, Inc.
        6000 Mountain Shadows Dr.
            Austin, Texas 78735
         Phone/Fax 512-288-5533
  [log in to unmask]   www.csl-sira.com
----------------------------------------------------------------


----- Original Message -----
From: "Uli Flenker; Raum 704" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 16, 2001 12:28 PM
Subject: 13C and 15N in Caffeine


> Dear list,
>
> has anybody experience with carbon and nitrogen isotopes (natural
> abundance) in caffeine? If there is any variation, are there isotopic
> signatures of different sources?
>
> A quick look at the literature (PubMed) gave no results.
>
> Many thanks in advance, and ...
>
>         ... happy new year to everyone!!!
>
>
>         Uli Flenker
>         Institute of Biochemistry
>         German Sports University Cologne
>         Carl-Diem-Weg 6
>
>         50933 Cologne / Germany
>
>         Phone 0049/0221/4982-493