As stated above, the studied phenolic acids are very unstable and
easily oxidized – mostly while in contact with BGE during separation.
This led us to examine the stability of both solutions as
dissolved in BGE. The electrolyte used in preliminary tests was
40 mM borate buffer at pH 9.0. The intensity and shape of the
absorption spectra for both phenolic acids was found to change with
time after 2 days. No degradation of the phenolic acids was thus to
be expected since their separation took less than 10 min.