I would like to use NH4H2PO4 to prepare an HPLC Buffer. Does any one know the PKa to know the pH range to prepare a correct buffer

Thanks

pKa for Phosphate: 2.1, 7.2, 12.2
pKa for ammonia: 9.2
So the buffer ragnes are: 2.1+/-1.0; 7.2+/-1.0, 9.2+/-1.0 and 12.2+/-1.0.

Just remember that phosphate is not te best choice when using MS.

An obvious question would be: what pH do you wish to operate at and why? Then you choose your buffer.

I'm trying to go to a pH 4.0. How about HCOONH4 ??

Thanks

good!