Development and validation of a capillary electrophoresis method for direct measurement of isocitric, citric, tartaric and malic acids as adulteration markers in orange juice

Fruit juices each have very distinct organic acids profiles that can be use d as fingerprints for establishing authenticity. A method has been develope d, optimised and validated for measuring by capillary electrophoresis citri c, isocitric, malic and tartaric acids as authenticity markers in orange ju ices, without any sample treatment other than dilution and filtration. Fina l conditions were phosphate buffer 200 mM, pH 7.50, -14 kV as applied poten tial, and 57 cm length neutral capillary. Detection was direct UV at 200 nm . Different kinds and marks of orange juice, chosen from the great variety existent in the market, were analysed and clear differences could be found between them and just pressed orange juice. (C) 2000 Elsevier Science B.V. All rights reserved.