Dear Marilyn, Bill and else,
Contamination with N2 would require an 'impurity' of 50% (neglecting the
m/z 30 contribution from 15N15N and the variable NO+ contribution). This
can be ruled out safely.
German CO obviously is produced using the watergas reaction (synth.gas).
Thus, the oxygen is from the water (not from the coal, Marilyn).
A fractionation in a  single step would produce a depletion of estimated
50 per mill at most. For such a large fractionation, the system would
have to operate close to threshold conditions. Thus, the membrane
purification Marilyn describes must be a terribly efficient production
facility for 18O enriched CO (and CO2) on the waste side. I would bet
for the company on the stock market.
Cheers    Willi

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Willi A. Brand, Stable Isotope Laboratory       [log in to unmask]
Max-Planck-Institute for Biogeochemistry
Carl-Zeiss-Promenade 10, 07745 Jena, Germany    Tel   +49-3641-643718
P.O.Box 100164, 07701 Jena, Germany             Fax:  +49-3641-643710
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