SIMULTANEOUS DETERMINATION OF INORGANIC ANIONS AND CARBOXYLIC-ACIDS IN WINE USING ISOCRATIC SEPARATION ON A PERMANENTLY COATED REVERSED-PHASE COLUMN AND UV INDIRECT DETECTION

A method for the separation and determination of both inorganic anions and carboxylic acids using a Nova-Pak C-18 column permanently coated with n-cetylpyridinium chloride is described. A 0.4 mM (pH 4.9) aqueou s potassium phthalate acid solution was used as the mobile phase. By c areful selection of the eluent pH (the factor which mostly affects ret ention) isocratic separation of both inorganic anions (chloride, nitri te, bromide, nitrate and sulphate) and carboxylic acids (lactic, succi nic, malonic, malic, maleic and tartaric) in wine was carried out in a bout 20 min. These analytes were determined at ng level using indirect UV detection. Satisfactory reproducibility of the results was obtaine d even after a 4 month period of continual use of the column. Subseque ntly, re-coating the column did not produce any changes in the expecte d analytical results. Accuracy and precision of the results were check ed by determining recoveries of spiked samples for each analyte. Avera ge recoveries between 97.4% and 108.3% were obtained.