Remote measurements, nitrogen species

The nitrogen species enter the atmosphere from a variety of natural and anthropogenic sources (7). The largest sources are concentrated in urban and industrialized areas. The levels of the species in the atmosphere vary from hundreds of parts per billion by volume (ppbv, that is, 10 9 mole fraction) in these source regions to below one part per trillion by volume (pptrv, 10"12 mole fraction) in remote areas. Even at the pptrv level, these species can play significant roles in atmospheric chemistry, and measurements of species at the sub-pptrv level can yield useful information concerning atmospheric photochemistry. 

Nitrogen can also be used as a remote label the exocyclic amino group of adenine, which is readily inserted into adenosine by reaction of chloropurine riboside with ammonia and easily removed by adenosine deaminase, is being used in our laboratory for measurement of 0 isotope effects in the y-phosphate of ATP. In this case, 0.36% of the N-, 0-labeled species is mixed with 99.6% of the " N-labeled material to restore the natural abundance of in the amino group of adenine. Depleted C and N are commercially available. 

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