Počet záznamů: 1

OXIDATION PATHWAYS OF NATURAL DYE HEMATOXYLIN IN AQUEOUS SOLUTION

  1. 1.
    0354402 - UFCH-W 2011 RIV CZ eng J - Článek v odborném periodiku
    Sokolová, Romana - Degano, I. - Hromadová, Magdaléna - Kocábová, Jana - Gál, Miroslav - Valášek, Michal
    OXIDATION PATHWAYS OF NATURAL DYE HEMATOXYLIN IN AQUEOUS SOLUTION.
    Collection of Czechoslovak Chemical Communications. Roč. 75, č. 11 (2010), s. 1097-1114 ISSN 0010-0765
    Grant CEP: GA ČR GA203/09/1607; GA ČR GA203/08/1157; GA MŠk OC 140
    Výzkumný záměr: CEZ:AV0Z40400503; CEZ:AV0Z40550506
    Klíčová slova: hemotoxylin * oxidation * dye degradation * cyclic voltammetry
    Kód oboru RIV: CG - Elektrochemie
    Impakt faktor: 0.853, rok: 2010

    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.
    Trvalý link: http://hdl.handle.net/11104/0193411