CAPILLARY ELECTROPHORESIS OF ANTS LABELED OLIGOSACCHARIDE LADDERS ANDCOMPLEX CARBOHYDRATES

The detection limits of the ANTS (8-aminonaphthalene-1,3,6-trisulfonic acid) label and ANTS maltose as a model carbohydrate conjugate were i nvestigated with on-column UV and laser induced fluorescence detection . Under capillary electrophoresis conditions, the concentration and ma ss detection limits were found to be 5 x 10(-7) mol/l or 8 femtomole w ith UV and 5 x 10(-8) mol/l or 400 attomole with laser induced fluores cence detection, respectively. Including the derivatization reaction, the best concentration detection limit increases to 1 x 10(-6) mol/l c arbohydrate. A model calculation shows that these detection levels are still insufficient to match those of current protein sequencing proto cols. Derivatization conditions for dextran and polygalacturonic acid ladders are described with subsequent fast separation in a capillary e lectrophoresis system under acidic pH buffer conditions. Up to 30 olig omers could be separated in less than 10 min. The application of ANTS labelled carbohydrate analysis in the food industry is demonstrated wi th the carbohydrate fraction of sweets and the kinetic monitoring of t he hydrolysis of polygalacturonic acid. The described ANTS derivitizat ion protocol works with as little as 5 mu g carbohydrate as demonstrat ed with a complex oligosaccharide labelled in a reaction volume as lit tle as 2 mu l. To demonstrate the applicability of this approach to co mplex carbohydrate analysis, an oligosaccharide mixture derived from h uman Immunoglobuline G was labelled and separated within 5 min. Separa tion efficiency and speed are superior to state-of-the-art chromatogra phic methods. Both electrophoretic and chromatographic methods are com plementary because of their different separation mechanism. The implic ations of using capillary electrophoresis with laser induced fluoresce nce and appropriate labelling strategies for structural and compositio nal analysis of complex carbohydrates are discussed.