A rapid method for the determination of total l-ascorbic acid in fruits and vegetables by micellar electrokinetic capillary chromatography

A rapid micellar electrokinetic capillary Chromatographic method for the determination of the total l-ascorbic acid content of a variety of fruits and vegetables is described. The vitamin is extracted from the foods with 3% metaphosphoric acid and stabilized with aqueous 0.2% d,l-dithiothreitol before analysis. d-Erythorbic acid is used as the internal standard. The analyses are performed with 75 μm fused silica capillary columns (40 cm effective length to the detector for fruits and 50 cm effective length to the detector for vegetables) using a buffer consisting of 0.05 m sodium deoxycholate, 0.01 m sodium borate and 0.01 m potassium dihydrogen orthophosphate. The method has the same order of repeatability, is faster and more cost effective than the high-performance liquid Chromatographic method that is currently used in the authorsʹ laboratory.