The determination of glucose, sucrose and fructose by the method of capillary electrophoresis
AbstractThe possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0,5% potassium sorbate, 0,62% cetyltrimethylammonium bromide, and 0,02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current – 54±4 μA, capillary thermostating at 24 °C is applied, the analysis time – 15 min. The detection limits for fructose and glucose is 0,03 g/dm3 to 0,07 g of sucrose/dm3 . Linearity is stored for each component to 5,0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10-4sm2V-1sec-1): fructose – 3,12, glucose – 3,03, sucrose – 2,74. Approximate time of release: glucose – 13 min, sucrose – 13,5 min, fructose – 12,5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results.
Keywords:capillary electrophoresis, electrolyte, juice, sugar, mobility detection limit, the migration