API 5L - Nitrogen Operating Medium

Doesn't it already say in those specifications? If so read them. If not, then please explain the relevance for their inclusion in the post.

When you say "quantity" it sounds more like a volume question. When you ask for "%" it is a quality issue.

Which one of both is it and what context do you need to know this for?

I would take it as pure as you can get/make it since you try to avoid an explosion. How much depends on the operation.

"someone urgently tell me" is a sign of desperation that should never be needed, if you are qualified and properly prepared.

As PWSlack said read the spec.

As the fictional character Sheldon Cooper PhD. would say in the most urgent way "Yes, someone can tell you the quantity of Nitrogen to meet an API standard. I doubt you'll understand it. If you could understand it, you would just read the standard yourself."

Available for URGENT download:

API Standards - Immediate PDF Downloads at IHS - global.ihs.com‎