Dear All,

I have an idea for using atmospheric N to calibrate my N2 reference gas
and need to know if anyone has tried it or if it is a fundamentally bad
idea. I have a CF-IRMS system consisting of A Carlo Erba NA 1500-CONFLO
II interface-Delta-s MS. Some time ago I forgot to turn the purge gas
flow on to the auto sampler, all the N-15 values were very close to 0.0.
So now I need to change my N2 reference tank. I don't have a dual inlet
to calibrate the gas. My plan is to use the isotopic value for
atmospheric N2 obtained by not purging the auto sampler relative to my
present reference gas to then calibrate my new tank of reference gas.
So, there may be something theoretically wrong with this idea? If so let
me know.

Thanks in advance,
Pat Anderson
Great Lakes WATER Institute