Chromatography Forum

I need to mix up a buffer of TEAA to try a separation for a chromatography class. I have TEA (98%) and glacial acetic acid available. I found a recipe online for mixing TEAA. 55.64 ml triethylamine, 22.89 ml acetic acid brought up to 4L.

Do I then just adjust the pH down to 7 or below with additional acetic acid?

Should I degas the water prior to mixing in the TEA and acetic acid? I don't want to lose the volatile amine or acetic acid. Can I still use the inline degassing unit prior to the pump in the HPLC?

Thank you.

Hi ,

First of all you need to know what you are trying to separate. Depending on the PKA's of the molecules a certain pH could be needed to separate compounds otherwise if they are to close (ex: pka coumpound 1 at 4.5 and your mobile phase pH is 4) you could get an equilibrium between 2 phases of that compound. What kind of column you want to use or that you have to work with? I know here we are using TEA with acetic acid and water but we also add a salt in it. Finally, most of mobile phase we work are under pH 7 so that would mean probably addition of acetic acid down to the pH wanted.


Hope this help!


Willy the ''GC''

Sorry if i didnt respond to your questions......

1-Measure the pH of the mix your doing. Addition of Acetic acid will lower the pH. TEA will raise it.

2- You can filter degas the final mixed mobile phase. Even though you smell TEA doesnt mean you loose too much that it could make a difference in the results. TEA smells at low concentration.


Willy the ''GC''

Thanks! It's working.