Hi David,

You may want to check out a paper we recently published on VOCs by TD-GC-IRMS. 

δ13C of volatile organic compounds (VOCS) in airborne samples by thermal desorption-gas chromatography-isotope ratio-mass spectrometry (TD-GC-IR-MS)  
Atmospheric Environment, Volume 40, Issue 18, June 2006, Pages 3381-3388 
Nicole Turner, Mark Jones, Kliti Grice, Daniel Dawson, Marisa Ioppolo-Armanios and Steven J. Fisher

If you have any further questions drop us an e mail.

Regards,

Kliti Grice


Dr Kliti Grice 
Associate Professor of Organic and Isotope Geochemistry
ARC (QEII) Fellow
Stable Isotope and Biogeochemistry Group Leader
Centre for Applied Organic Geochemistry
Department of Applied Chemistry
Curtin University of Technology
Perth 6845
WA
Australia

tel +61 8 9266 2474
fax + 61 8 9266 2300




-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Enno Bahlmann
Sent: Monday, 31 July 2006 3:42 PM
To: [log in to unmask]
Subject: 

Hi David,

I dont know if microwave desorption has ever been used
for Isotopic analysis of VOCs but you should also
consider this method as it offers several advantages
compared to conventional thermo desorption.
With a microvave oven you heat your sorbent more
uniform which prevents breakdown of your analytes.
Furtheron it is faster and  more complete compared to
conventional heating but anyway I guess you have to
cryofocus your analytes after desorption to prevent
isotopic fractionation.

Good luck

Enno



--- Widory David <[log in to unmask]> schrieb:

> Dear all,
> we are currently trying to set our equipment up for
> analysis of atmospheric
> VOC (on a Delta plus XP).
> For sampling, we are tending towards the use of
> small glass sorbent tubes.
> My main question would be to identify what is the
> most appropriate device
> for introduction into the GC-C/TC ? According to me
> we have to choose
> between a thermal desorption unit and solvent
> extraction followed by liquid
> injection (with a GC-PAL or similar). Can anyone
> share its experience on the
> pros and cons of each technique, as well as related
> papers ?
> Thanking you in advance.
> Cordially,
> David
>  
> 
> 
> Dr D. Widory
> 
> Stable Isotope Laboratory Manager
> 
> BRGM MMA/ISO
> 
> 3 avenue Claude Guillemin
> 
> BP 36009
> 
> 45060 Orléans Cedex 2
> 
> France
> 
> e-mail : [log in to unmask]
> 
> Tel : +33-(0)2 38 64 47 72
> 
> Fax : +33-(0)2 38 64 37 11
> 
>  
>
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