Isotachophoretic separation and behaviour of catechol derivatives

The separation and migration behaviour of ten catechol derivatives containing electrically neutral species were investigated by capillary tube isotachophoresis. In the usual migration system at pH 7.5 consisting of Tris buffer as the leading electrolyte and histidine as the terminating electrolyte, six of the catechols were separated but the other four with small acid dissociation constants could not be detected. However, by using boric acid as the terminating electrolyte and converting the catechols into anionic catechol-borate complexes in the migrating capillary, all ten catechols could be detected and nine of them could be separated even at pH 7.5.