Separation of disaccharides as their borate complexes by capillary electrophoresis with indirect detection in visible range

Borate complexation was used to make possible the separation of disaccharides by capillary electrophoresis with indirect detection. A high borate concentration did not affect the indirect detection sensitivity in as negative a way as predicted previously. The concentration sensitivity for sucrose was determined to be 2 m M at the borate concentration of 200 m M in running electrolyte. The newly introduced backround chromophore, p ‐nitrophenol, allows the monitoring of the separation process in a visible range at 400 nm. This also enables the indirect detection of UV‐absorbing compounds in complex mixtures in which they would be impossible to detect with a UV‐absorbing backround chromophore.