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  Home > JCE Print > Journal of Chemical Education > Issues > 2002  > January  >
In the Laboratory
Coulometric Titrations in Wine Samples: Studies on the Determination of S(IV) and the Formation of Adducts
Denise Lowinsohn and Mauro Bertotti
Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-900, Brazil
Cover
January 2002
Vol. 79 No. 1
p. 103
Abstract
In this experiment, the sulfite in white wine samples is quantified by coulometric titration with iodine, using a procedure that minimizes errors due to air oxidation. Some aspects of the distinction of S(IV) forms in such matrices are discussed on the basis of the formation of adducts between sulfite and carbonyl compounds present in the wine. The reactivity of these S(IV)-bound compounds toward the reaction with iodine is addressed and the stability of the adducts as the sample pH is changed is discussed.

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*  Citation
 Lowinsohn, Denise; Bertotti, Mauro. J. Chem. Educ. 2002 79 103.
*  Keywords
 Analytical Chemistry; Electrochemistry; Food Science; Laboratory Instruction; Quantitative Analysis
*  History
 Created:
Last Updated:		 December 3, 2001
March 16, 2005
Link to Letter added (April 2004).
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