Penzkofer, A. and Tyagi, A. and Kiermaier, J. (2011) Room temperature hydrolysis of lumiflavin in alkaline aqueous solution. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 217 (2-3). pp. 369-375. ISSN 1010-6030,
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The degradation of lumiflavin (7,8,10-trimethyl-isoalloxazine, LF) in aqueous 1-4M sodium hydroxide solutions (pH 14-14.6) at room temperature in the dark was studied by absorption spectroscopy, fluorescence spectroscopy, and mass spectrometry. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes at certain times after sample preparation were determined. The degradation products were analyzed by combined liquid chromatography and mass spectrometry. Lumiflavin is present in anionic form (LF-). It degrades to anionic 7,8-dimethyl-isoalloxazine (DMIA(-)), anionic methyl-isoalloxazine (MIA(-)), and to the quinoxaline derivatives of 1,2-dihydro-2-keto-1,6,7-trimethyl-quinoxaline-3-carboxylic acid (QO1), 2-methoxy-6,7-dimethyl-quinoxaline-3-carboxylic acid (QO2), methyl-quinoxaline-2-ol (QO3), and 3-hydroxy-1,6,7-trimethy1-1H-quinoxaline-2-one (QO4). The rate constants of the NaOH catalyzed lumiflavin degradation are determined for the investigated samples. (C) 2010 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | VITAMIN B-2; CHEMICAL-REACTIONS; FLASH-PHOTOLYSIS; ANTI-DERMATITIS; HEAT-STABILITY; PH-DEPENDENCE; FLUORESCENCE; FLAVINS; RIBOFLAVIN; ABSORPTION; Lumiflavin; Alkaline hydrolysis dynamics; Quinoxaline derivatives; 7.8-Dimethyl-isoalloxazine; Methyl-isoalloxazine; Absorption cross-section spectra; Fluorescence quantum distributions; Fluorescence lifetimes; Hydrolysis rate constants |
| Subjects: | 500 Science > 530 Physics 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer Chemistry and Pharmacy > Institut für Organische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 29 Jun 2020 05:29 |
| Last Modified: | 29 Jun 2020 05:29 |
| URI: | https://pred.uni-regensburg.de/id/eprint/21381 |
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