SIMULTANEOUS DETERMINATION OF ASCORBIC-ACID AND DEHYDROASCORBIC ACID IN PLANT MATERIALS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The adaptation of an isocratic reversed-phase ion-pairing high perform ance liquid chromatographic method in combination with derivatization of dehydroascorbic acid by 1,2-phenylenediamine prior to injection for simultaneous determination of ascorbic acid and dehydroascorbic acid in plant materials is presented. Extraction was carried out in meta-ph osphoric acid, and hexadecyltrimethylammonium bromide was used as the ion-pairing reagent. Ascorbic acid was detected directly at 248 mm whi lst dehydroascorbic acid was simultaneously detected as the 1,2-phenyl enediamine derivative at 348 mn. Resolution and accuracy were shown to be satisfactory for naturally occurring amounts in plant materials as demonstrated with extracts of Norway spruce (Picea abies (L.) Karst.) needles.