Bruce et al.,
we also have lecture bottles of very light CO and have discussed the fact
that the CH4 used to make it is probably light (d13C= -40 to -80 per mil),
and then whatever process is used to make CO must favor the 12C.  But what
this process is...

if anyone knows how/where to obtain heavier CO, I'd be very interested.

cheers,
Cyndi

Cyndi Brock
U.S. Geological Survey
DFC, Bldg 21, MS 963
Denver, CO  80225

office: 303-236-0278
lab:    303-236-7694
fax:    303-236-4930
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