Any thoughts on a procedure for measuring isotope ratios in
gas-phase NO2? Making the 15N measurements is easy and published methods
exist. But the 18-O measurements? We have collected NO2 with a mist
chamber to produce nitrite, but this will produce a rapid exchange of
oxygen with water. So the question really is a two-step one:
How to collect NO2 without fractionating it for oxygen?
How to measure the isotope ratios? Pure NO2 could be introduced into the
source, I suppose, but has anyone done this?