Anhydrous ampicillin - (Jul/15/2009 )
Our lab recently bought anhydrous ampicillin instead of ampicillin sodium salt. According to Sigma, the anhydrous ampicillin dissolves at 50mg/ml in 1 M ammonium hydroxide. My question is, if I use the amp at 100mg/ml (so 2ul/ml media) will the presence of the ammonium hydroxide negatively effect the bacteria cells? Or is the amount so small it is negligible?
we made the same mistake once. In the end we just threw it away and bought the sodium salt. It was not working properly in our hands although we followed the instructions.
I would have say the same as stardust : ampicillin is not so expensive, so buy the right one to be sure every thing is fine, and you won't lose your time