Method Development for the Simultaneous Determination of Carboxylic Acids, Phenolic Compounds, and Sorbic Acid in White Wines

Abstract

A reversed phase liquid chromatographic method was developed for the simultaneous determination of carboxylic acids and phenolics in white wines. The samples, diluted, were injected onto a Spherisorb ODS-2 column with a gradient of sulfuric acid (pH 2.5) / methanol as mobile phase. A diode array detector was used which was set at 210nm for carboxylic acids and altered to 278nm, during the run, for phenolics and sorbic acid. The identification of compounds was based on retention time, co-chromatography and UV spectrum. Some clean-up methods (sep-pak C₁₈ and an ion exchange column) were tested and did not improve the results. The analysis was simple, with no sample preparation. Application of this method was illustrated by analyses of Brazilian Welchriesling wines.