Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide

Yogendra Kumar, M. S. and Gowtham, M. D. and Mahadevaiah and Agendrappa, G. (2006) Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide. Analytical Sciences, 22 (5). pp. 757-761. ISSN 1348-2246

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The proposed work describes a simple spectrophotmetric as well as a titrimetric method to determine sulfur dioxide. The spectrophotometric method is based on a redox reaction between sulfur dioxide and iodine monochloride obtained from iodine with chloramine-T in acetic acid. The reagent iodine monochloride oxidizes sulfur dioxide to sulfate, thereby reducing itself to iodine. Thus liberated iodine will also oxidize sulfur dioxide and reduce itself to iodide. The obtained iodide is expected to combine with iodine to form a brown-colored homoatomictriiodide anion (460 nm), which forms an ion-pair with the sulfonamide cation, providing exceptional color stability to the system under an acidic condition, and is quantitatively relatd to sulfur dioxide. The system obeys Beer's law in the range 5 - 100 mu g of sulfur dioxide in a final volume of 10 ml. The molar absorptivity is 5.03 x 10(3) l mol(-1) cm(-1), with a relative standard deviation of 3.2% for 50 mu g of sulfur dioxide (n = 10). In the titrimetric method, the reagent iodine monochloride was reduced with potassium iodide (10%) to iodine, which oxidized sulfur dioxide to sulfate, and excess iodine was determined with a thiosulfate solution. The volume difference of thiosulfate with the reagent and with the sulfur dioxide determined the sulfur dioxide. Reproducible and accurate results were obtained in the range of 0.1 - 1.5 mg of sulfur dioxide with a relative standard deviation of 1.2% for 0.8 mg of sulfur dioxide (n = 10).

Item Type: Article
Subjects: C Chemical Science > Chemistry
Divisions: Department of > Chemistry
Depositing User: lpa manjunath user
Date Deposited: 21 Aug 2019 05:37
Last Modified: 01 Oct 2019 05:24

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