CE Determination of Carbohydrates Using a Dipeptide as Separation Electrolyte

The influence of aminoacid and peptide type buffers as the separation electrolyte to the resolution of underivatized neutral carbohydrates in capillary electrophoresis was investigated. With the use of plain glycylglycine as the background electrolyte, a noticeable improvement in the resolution of carbohydrates was observed. Without any additive, 50 mmol L⁻¹ glycylglycine electrolyte at pH 12 provides both the fast separation and indirect detection of sugars. The electrophoretic mobilities of 16 sugars were calculated at this buffer and the combinations of 10 sugars were simultaneously detected. The method was applied to the determination of sucrose, glucose, and fructose in commercial juice samples.