Determination of mono- and disaccharides by capillary electrophoresis with contactless conductivity detection

The separation and detection of common mono- and disaccharides by capillary electrophoresis (CE) with contactless conductivity detection (CCD) is presented. At high values of pH, the sugars are converted to anionic species that can be separated by CE and indirectly detected by CCD. The main anionic species present in the running electrolytes are hydroxide and phosphate, which have greater mobility than the ionized sugars, and, thus, the indirect detection is possible. The method was applied to analysis of glucose, fructose, and sucrose in soft drinks, isotonic beverages, fruit juice, and sugarcane spirits. Galactose was used as internal standard in all cases. Plate numbers range from ca. 70,700 to 168,200 and the limits of detection from 13 to 31 microM.