Comparative Characterization of Different Versions of Electrophoretic Determination of Mono- and Disaccharides with Prior Derivatization

The following versions of the electrophoretic determination of carbohydrates after derivatization are considered: reductive amination with p-aminobenzoic acid ethyl ester and condensation with 1-phenyl-3-methyl-5-pyrazolone. The derivatization products were separated by capillary zone electrophoresis and in the micellar mode and their characteristics were compared. Reductive amination followed by determination by micellar electrokinetic chromatography demonstrated the best values of separation efficiency (400 000–650 000 theoretical plates), selectivity (2.1–2.4), and limit of detection (LOD) (0.8–2.9 μg/mL). Derivatization conditions for reductive amination were optimized using a central composite experimental design. In-capillary sample preconcentration samples through sweeping significantly improved the LOD and enhancement factors of 13–19 were achieved. A proof-of-concept possibility of in-capillary reductive amination using detergent micelles as carriers for the derivatization agent was demonstrated. Both derivatization techniques were successfully applied to the analysis of baby food, showcasing their practical applicability.