well, what I am doing is using helium to purge oxygen out of a system I have developed to measure trace concentrations of Nitric Oxide so I can try to solve some of the mysteries associated with the compound. I have been searching to see if there is a Math/Physics model for the mixture of gaseous solutions. The reason is because i have cleared all the leaks of my machine as well as put it in a nitrogen atmosphere and for some reason when My sample makes it to the mass spec i seem to be losing about 87% of the original sample.