Ascorbic, Dehydroascorbic and Isoascorbic Acid Simultaneous Determinations by Reverse Phase Ion Interaction HPLC

Abstract

ABSTRACT Detection was by UV absorbance (after pre‐column derivatization of dehydroascorbic acid with 1,2‐phenylenediamine). When absent, isoascorbic acid could be used as internal standard. Isocratic separation was accomplished in 11 min using the eluent, methanol‐water (5:95, v/v) containing potassium dihydrogen phosphate (50 mM) and the counterion hexadecyltrimethylammonium bromide (5 mM). Sample preparation steps using Sep‐pak C18 cartridge were minimal. Ten ppm could be detected for each compound with good reproducibility (c.v. <2%). The method was used to determine vitamin C content in selected foods and beverages.