Hallo Frank,
You can determine the N2O/CO2 ratio directly with your mass spec, if you
measure the masses 30 (NO) and 28 (CO). You may find details on this
measurement method and on the correction of the isotopic values of CO2 in
"Friedli and Siegenthaler, Influence of N2O on isotope analyses in CO2 and
mass-spectrometric determination of N2O in air samples, Tellus(1988), 40B,
129-133."
Hope it will help,
Silvio
-------------------------------------------
Silvio Borella /\
Klima- und Umweltphysik //\\
Phys. Inst., Uni Bern ///\\\
Sidlerstr. 15 ///\\\
CH-3012 Bern ////\\\\
Switzerland ///\\\
//II\\
Tel.: 031/631'44'70 II
Fax.: 031/631'44'05 II
e-mail: [log in to unmask] ********
http://www.climate.unibe.ch/~borella
-------------------------------------------
...common sense is nothing more than a
deposit of prejudices laid down in the
mind before you reach eighteen.
Albert Einstein
-------------------------------------------