What is the rough pH of Na-DCA when dissolved in water?
And what are the solubility limits?
I have previously made the mistake to think that NaDCA has a pKa of 1.25; that is wrong. That data is of course for the acid form which is a rather strong acid.
But the actual pH of the sodium salt dissolved in (distilled) water is still important. DCA tends to auto-catalyze its own breakdown rapidly at low pH (Henderson et al, Drug dev Ind Pharm, Vol20(15), p. 2425-37, 1994).
The question is, thus, do one need a buffer?
That relates to solubility - since useful buffers contain plenty of sodium ions.