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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Fast Spectrophotometric Determination of Iodine Value in Biodiesel and Vegetable Oils

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Soares, Samara [1] ; Rocha, Fabio R. P. [1]
Total Authors: 2
[1] Univ Sao Paulo, Ctr Energia Nucl Agr, Av Centenario 303, BR-13416000 Piracicaba, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of the Brazilian Chemical Society; v. 29, n. 8, p. 1701-1706, AUG 2018.
Web of Science Citations: 1

Iodine value is an important quality parameter for evaluation of the oxidative stability of biodiesel and vegetable oils, but the official methods are time-consuming and demand large amounts of reagents and solvents. The present work describes a novel procedure for determination of iodine value based on the discoloration of a triiodide aqueous solution due to halogenation of the unsaturated compounds in the samples. Iodine is extracted to the organic phase and consumed proportionally to the amount of unsaturated compounds in the samples. Thus, the remaining fraction of I-3(-) quantified by spectrophotometry in the aqueous phase is inversely proportional to the concentration of unsaturated compounds. For biodiesel samples, responses were linear from 10 to 106 g I-2 per 100 g, with coefficient of variation and limit of detection estimated at 5.0% (n = 8) and 2.5 g I-2 per 100 g, respectively. The corresponding values for vegetable oils were 20 to 140 g I-2 per 100 g, 3.0% (n = 10), and 7 g I-2 per 100 g, respectively. The procedure consumed only 1.2 mL of sample, 365 mu g of I-2, and 42 mg of KI with ca. 2.4 mL of waste generated per determination. The results agreed with those obtained by the official methods at the 95% confidence level. (AU)

FAPESP's process: 16/00138-0 - Development of fast analytical procedures for biodiesel quality control
Grantee:Samara Soares
Support type: Scholarships in Brazil - Master