Determination of Total Sulfite in Wine by Ion Chromatography after In-Sample Oxidation

• Published in: Journal of agricultural and food chemistry Vol. 58; no. 17; pp. 9463 - 9467
• Main Authors: Koch, Matthias, Köppen, Robert, Siegel, David, Witt, Angelika, Nehls, Irene
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.09.2010
• Subjects: analysis; Analytical Methods; Biological and medical sciences; chemistry; Chromatography, Liquid; Chromatography, Liquid - methods; equipment performance; Fermented food industries; food analysis; food composition; food contamination; Food industries; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide; Hydrogen Peroxide - chemistry; ion exchange chromatography; Limit of Detection; methods; model food systems; oxidation; Oxidation-Reduction; sulfites; Sulfites - analysis; Wine; Wine - analysis; wine quality; wines; Wines and vinegars; optimized Monier−Williams method; wine analysis; hydrogen peroxide oxidation; IC; Sulfur dioxide; Wine; Sulfites; Hydrogen; Sample; Method; Alcoholic beverage; Ion chromatography; Oxidation; Peroxides; optimized Monier-Williams method
• ISSN: 0021-8561; 1520-5118; 1520-5118
• DOI: 10.1021/jf102086x

Sulfur dioxide (SO2) or sulfites are the most common preservatives used in winemaking. The level of total SO2 is subject to regulation. Currently, the regulatory determination of total SO2 (including sulfites) is done by the optimized Monier−Williams (OMW) method, which includes time-consuming distillation and titration steps. This paper describes the development and application of an alternative, rapid, straightforward, and reliable method for the determination of total sulfite in wine. In this method, a simple oxidation step using alkaline hydrogen peroxide (H2O2) solution is followed by ion chromatographic (IC) analysis of sulfate coupled with conductometric detection. Thirteen wines were analyzed in order to compare the in-sample oxidation method with the OMW-procedure. A t-test revealed satisfying compliance regarding sample preparation, i.e., alkaline H2O2 treatment and acidic distillation (OMW method). Comparable results were also obtained between IC analysis and acid/base titration. Our results indicate that the novel method (limit of quantification: 4 mg SO2 L−1) is well suited for the cost-efficient monitoring of regulatory limits.