[googleviet]

I look up that the highest solubility of ammonium in Ethanol is 15% but I don't know how to prepare this solution for my experiment. Can you help me? Thanks very much 

[Arkcon]

You probably should just purchase it, but you could generate NH3 by some chemical reaction, dry it, then bubble it through ethanol, until saturated.  Or if you have access to liquid NH3, mix a slight excess with ethanol, and allow to bubble free, for a bit. 

Of course, someone with a legitimate use, and the technical skill for the use of ammonia saturated ethanol, can fill in the blanks that I've left themselves for safety and environmental responsibility, right?

Just have someone in your purchasing dept. order it.