A SIMPLE ION-EXCHANGE CHROMATOGRAPHIC DETERMINATION OF NONVOLATILE ORGANIC-ACIDS IN SOME SPANISH EXOTIC FRUITS

High-performance liquid chromatography (HPLC) permits accurate determination of non-volatile acids in fruit. The Spanish exotic fruits assayed were kiwi fruits (Actinidia chinensis), cvs Hayward, Bruno, Monty and Abbot; mangoes (Mangifera indica), cvs Smith and Lippens; papayas (Carica papaya), cv Solo; pineapples (Ananus comosus), cv Smooth Cayenne; and bananas (Musa cavendishii), cv Enana. Sample preparation for HPLC analysis basically consisted of methanol extraction, followed by an easy clean-up with a C18 cartridge. Separation of the different acids was accomplished using an ion-exchange column and detection was monitored at 214 nm. Reproducibility of the minor organic acids was quite acceptable, and the procedure described offers a rapid analytical alternative to gas chromatography. Oxalic, oxoglutaric, citric, galacturonic, tartaric, ascorbic, L-malic, quinic, succinic, fumaric and D-malic acids can be quantified by this method.