Hello Jorge,
Using a J&W GS-Gaspro column, temperature program -50 for 3 minutes then to
+260 at 25 degrees per minute, Q=4ml/min, I did NOT achieve separation of
CO2 from some minor component in NGS-2. Worked ok for all the hydrocarbons
but method needs tuning for the CO2, or try different column.
Cheers
Robert

> -----Original Message-----
> From: Stable Isotope Geochemistry 
> [mailto:[log in to unmask]] On Behalf Of Jorge Teixeira da Silva
> Sent: Friday, 19 January 2007 8:09
> To: [log in to unmask]
> Subject: [ISOGEOCHEM] 18O CO2 Natural Gas
> 
> Hi all,
> 
> We need to know the 18O from the CO2 of reference material 
> NGS2 NIST Gas. 
> We need to set a procedure to measure the 18O from CO2 of 
> natural gas samples by GC/C IRMS (GCCIII & MAT252). We need 
> to establish the 18O of our
> CO2 LabTank reference gas under GC conditions for natural 
> gas. I hope not to face interferences under mass 46. I would 
> be glad to hear your opinion.
> 
> Regards
> 
> Jorge Teixeira
> PETROBRAS/CENPES/Organic Geochemistry Lab
>