Hello Inigo,

One can make modern CO2 by burning a tree as long as you choose one that is 
less than 50 years old. 

Or one can make "2005" modern CO2 by burning grass clippings, hay, straw or 
anything that grew this year. Office paper will also work (the recycler and 
shredder can have a rest).

The ideas of bubbling gas through a trap and of checking the delta13C are 
excellent.

Irene Ellis
IsoTrace Lab
University of Toronto

On Thu, 6 Oct 2005 12:13:47 -0400, Inigo Auza-Aldasoro 
<[log in to unmask]> wrote:

>Dear all,
>
>we are searching for a CO2-gas supplier with modern 14C signature. We need
>it to use as working standard. The local suppliers process the CO2 from
>dead 14C sources (natural gas, carbonates...)
>
>Does anybody know about any CO2-gas supplier which obtains the CO2 from
>modern carbon source (with "alive 14C signature")?
>
>Thanks a lot,
>Inigo.
>
>Inigo Auza-Aldasoro
>Environmental Tracers Lab,
>School of Civil Engineering, Queen's Univ. Belfast
>David Keir Building, Stranmillis Rd.
>BELFAST
>BT9 5AG
>N. Ireland.
>=========================================================================