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OXIDATION PATHWAYS OF NATURAL DYE HEMATOXYLIN IN AQUEOUS SOLUTION
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SYSNO ASEP 0354402 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title OXIDATION PATHWAYS OF NATURAL DYE HEMATOXYLIN IN AQUEOUS SOLUTION Author(s) Sokolová, Romana (UFCH-W) RID, ORCID, SAI
Degano, I. (IT)
Hromadová, Magdaléna (UFCH-W) RID, ORCID, SAI
Kocábová, Jana (UFCH-W) RID
Gál, Miroslav (UFCH-W)
Valášek, Michal (UOCHB-X)Source Title Collection of Czechoslovak Chemical Communications. - : Ústav organické chemie a biochemie AV ČR, v. v. i. - ISSN 0010-0765
Roč. 75, č. 11 (2010), s. 1097-1114Number of pages 18 s. Language eng - English Country CZ - Czech Republic Keywords hemotoxylin ; oxidation ; dye degradation ; cyclic voltammetry Subject RIV CG - Electrochemistry R&D Projects GA203/09/1607 GA ČR - Czech Science Foundation (CSF) GA203/08/1157 GA ČR - Czech Science Foundation (CSF) OC 140 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) CEZ AV0Z40400503 - UFCH-W (2005-2011) AV0Z40550506 - UOCHB-X (2005-2011) UT WOS 000284230500003 DOI 10.1135/cccc2010096 Annotation The oxidation mechanism of hematoxylin was studied in phosphate buffers and 0.1 M KCl by cyclic voltammetry and UV-Vis spectroscopy under deaerated conditions. The redox potential of hematoxylin in buffered solution strongly depends on pH. A two electron oxidation is preceded by deprotonation. The homogeneous rate of deprotonation process of hematoxylin in 0.1 M phosphate buffer is k(d) = (2.5 +/- 0.1) x 10(4) s(-1). The cyclic voltammetry under unbuffered conditions shows the distribution of various dissociation forms of hematoxylin. The dissociation constants pK(1) = 4.7 +/- 0.2 and pK(2) = 9.6 +/- 0.1 were determined using UV-Vis spectroscopy. The final oxidation product was identified by gas chromatography with mass spectrometry detection as hemathein. The distribution of oxidation products differs under buffered and unbuffered conditions. The dye degradation in natural unbuffered environment yields hemathein and hydroxyhematoxylin, which is absent in buffered solution. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2011
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