ION-PAIR CHROMATOGRAPHY AND PHOTODIODE-ARRAY DETECTION OF VITAMIN-C AND ORGANIC-ACIDS

Ion-pair chromatography on an octadecylsilane column (ODS-2, 10 Aum) with an eluant containing potassium dihydrogen phosphate, tetrabutyl ammonium hydroxide, and methanol is used for the isocratic separation of a wide variety of organic acids, including ascorbic, citric, and phenolcarbonic acid metabolic pathways. Photodiode-array detection and chromatographic software allow for rapid and precise identification and peak purity tests for the whole separation profile. Optimization of the eluant pH and composition is also included. The method provides excellent resolution and allows for quantitation of some acids at very low concentrations. Selected fresh fruits and vegetables are analyzed using this method. © 1994 Oxford University Press.