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Materials 2014, 7(9), 6184-6193; doi:10.3390/ma7096184
Article

A Critical Comparison of Methods for the Analysis of Indigo in Dyeing Liquors and Effluents

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Received: 6 June 2014; in revised form: 25 August 2014 / Accepted: 25 August 2014 / Published: 29 August 2014
(This article belongs to the Special Issue Advances in Colorants 2014)
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Abstract: Indigo is one of the most important dyes in the textile industry. The control of the indigo concentration in dyeing liquors and effluents is an important tool to ensure the reproducibility of the dyed fabrics and also to establish the efficiency of the wastewater treatment. In this work, three analytical methods were studied and validated with the aim to select a reliable, fast and automated method for the indigo dye determination. The first method is based on the extraction of the dye, with chloroform, in its oxidized form. The organic solution is measured by Ultraviolet (UV)-visible spectrophotometry at 604 nm. The second method determines the concentration of indigo in its leuco form in aqueous medium by UV-visible spectrophotometry at 407 nm. Finally, in the last method, the concentration of indigo is determined by redox titration with potassium hexacyanoferrate (K3(Fe(CN)6)). The results indicated that the three methods that we studied met the established acceptance criteria regarding accuracy and precision. However, the third method was considered the most adequate for application on an industrial scale due to its wider work range, which provides a significant advantage over the others.
Keywords: indigo dye; method validation; hexacyanoferrate titration; spectrophotometric; dye baths; effluent indigo dye; method validation; hexacyanoferrate titration; spectrophotometric; dye baths; effluent
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Buscio, V.; Crespi, M.; Gutiérrez-Bouzán, C. A Critical Comparison of Methods for the Analysis of Indigo in Dyeing Liquors and Effluents. Materials 2014, 7, 6184-6193.

AMA Style

Buscio V, Crespi M, Gutiérrez-Bouzán C. A Critical Comparison of Methods for the Analysis of Indigo in Dyeing Liquors and Effluents. Materials. 2014; 7(9):6184-6193.

Chicago/Turabian Style

Buscio, Valentina; Crespi, Martí; Gutiérrez-Bouzán, Carmen. 2014. "A Critical Comparison of Methods for the Analysis of Indigo in Dyeing Liquors and Effluents." Materials 7, no. 9: 6184-6193.


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