Buffer at pH=5 - 5.5

[kresten]

Acid                      pKa
-------------------------
acetic acid             4.76
proprionic acid      4.86
pyridinium             5.23
piperazinium          5.55

see also:
http://www.embl-heidelberg.de/~toldo/Makebuf.html


hth
Kresten

> Can anyone suggest a suitable buffer that is stable at
> around pH = 5 - 5.5? I've tried many combinations of
> Lactic, citric, acetic, histidine and MES buffers
> without success. Buffer vendors such as Sigma seem to
> have a gap around pH 4 - 6.