Rapid determination of free sulfur dioxide in wine and cider by capillary electrophoresis.

Autor: Ashmore PL; Washington State University, Department of Food Science, Richland, WA 99354., Valdez F; Washington State University, Viticulture and Enology Program, Richland, WA 99354., Harbertson JF; Washington State University, Viticulture and Enology Program, Richland, WA 99354., Boulton RB; University of California, Department of Viticulture and Enology, Davis, CA 95616., Collins TS; Washington State University, Viticulture and Enology Program, Richland, WA 99354. Electronic address: tom.collins@wsu.edu.
Jazyk: angličtina
Zdroj: Journal of chromatography. A [J Chromatogr A] 2023 Apr 26; Vol. 1695, pp. 463936. Date of Electronic Publication: 2023 Mar 20.
DOI: 10.1016/j.chroma.2023.463936
Abstrakt: A novel method for the determination of "true" free sulfur dioxide (SO 2 ) in wine and cider was developed using capillary electrophoresis with direct ultraviolet-visible spectrophotometric detection (CE-UV/vis). Free SO 2 was measured in model solutions with different SO 2 -binding agents present (α-ketoglutarate, pyruvate, acetaldehyde, glucose, fructose, and malvidin-3-glucoside) as well as a variety of white and red wines and ciders. The CE method was compared to three conventional methods for measuring free SO 2 , the Ripper method, Aeration-Oxidation (AO), and pararosaniline by discrete analyzer (DA). While some statistically significant differences (p<0.05) were found between the four methods in unpigmented model solutions and samples, the values generally agreed. In the presence of anthocyanins in model solution and red wines, free SO 2 values found by CE were significantly lower than the other three methods (p<0.05). The difference in values found by Ripper and CE correlated strongly with anthocyanin content (R 2  = 0.8854) and even more strongly when accounting for polymeric pigments (R 2  = 0.9251). The results in red ciders differed from those in red wines, while the CE measured significantly lower free SO2 values than the other three methods, the difference in free SO 2 values measured by CE and Ripper correlated more closely with anthocyanin concentration (R 2  = 0.8802) than absorbance due to bleachable pigment (R 2  = 0.7770). The CE method was found to be rapid (4 min/injection), sensitive (LOD=0.5 mg/L, LOQ=1.6 mg/L free SO 2 in wine, 0.8 and 2.8 mg/L, respectively, in cider), robust, and repeatable (average RSD = 4.9%) and did not suffer from the issue of over-reporting free SO 2 in pigmented samples often observed with currently accepted methods.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023. Published by Elsevier B.V.)
Databáze: MEDLINE
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