Analysis of Carbohydrates by Capillary Zone Electrophoresis With on-Capillary Derivatization

Carbohydrates were on-capillary derivatized by p-hydrazine-benzenesulfonic acid (BHZ) and separated by capillary zone electrophoresis using 100 mM boric acid (pH 10.2) as running buffer. The derivatization was achieved by keeping the capillary tip introduced with sample in between two zones of labeling reagent at room temperature for 30 min. The detection limit of galactose and glucose were 15.6 and 31.2 μm, respectively, a bit higher than the corresponding values from pre-capillary derivatization (10.5 and 3.6 μM, respectively). Nevertheless the sample consumption was decreased by two to three orders of magnitude compared to the pre-capillary mode. Reproducible quantification of carbohydrates was demonstrated in the concentration range of 0.3–30 mM. The application of this method to determine the glucose in human serum was also present.