USE OF ION CHROMATOGRAPHY FOR THE MEASUREMENT OF ORGANIC-ACIDS IN FRUIT JUICES

A gradient ion chromatographic method to separate and determine main organic acids in fruit juices was developed. The method allows the separation of organic anions on Dionex OMNI PAC PAX-500 column by NaOH gradient elution and conductometric detection. The main organic acids of fruit juices (citric, malic, tartaric) were separated together with Other less abundant acids. More than 500 samples of fruit juices were analysed, mainly orange juices from Brasil, Italy, Florida, California, as well as apple, cherry, grape and blackcurrant juices of different origin. The method has shown a high sensitivity and a satisfactory accuracy. The method also allows the simultaneous separation of lactic and acetic acids, produced by microbiological spoilage of juices, and of some important inorganic anions such as chlorides and nitrates.