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Fluorescence quenching of fluoroquinolone antibiotics by 4-hydroxy-TEMPO in aqueous solution
- Source :
- Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 133:887-891
- Publication Year :
- 2014
- Publisher :
- Elsevier BV, 2014.
-
Abstract
- The fluorescence quenching of norfloxacin, danofloxacin, enrofloxacin and levofloxacin, belonging to a group of fluoroquinolone antibiotics, by 4-hydroxy-TEMPO was studied in aqueous solutions with the use of steady-state, time-resolved fluorescence spectroscopy as well as UV-VIS absorption spectroscopy methods. In order to understand the mechanism of quenching the absorption and fluorescence emission spectra of all fluoroquinolone antibiotics studied as well as decreases of their fluorescence were registered as a function of the 4-hydroxy-TEMPO concentration. No deviations from a linearity in the Stern-Volmer plots (determined from both, steady-state and time-resolved measurements) were observed. The fluorescence quenching mechanism was proved to be totally dynamic, what was additionally confirmed by the registration of Stern-Volmer plots at 5 temperatures ranging from 15 to 55°C. On the basis of theoretical calculations of fluoroquinolones' molecular radii and ionization potentials the mechanism of electron transfer was rejected. It seems that the fluorescence quenching is diffusion-limited and is caused by the increase of nonradiative processes, such as internal conversion or intersystem crossing. The Stern-Volmer quenching constants and bimolecular quenching constants were determined at the room temperature for all fluoroquinolone antibiotics studied.
- Subjects :
- Models, Molecular
Quenching (fluorescence)
Aqueous solution
Absorption spectroscopy
Chemistry
Danofloxacin
Hydroxylamine
Internal conversion (chemistry)
Photochemistry
Fluorescence
Atomic and Molecular Physics, and Optics
Fluorescence spectroscopy
Anti-Bacterial Agents
Analytical Chemistry
Cyclic N-Oxides
Spectrometry, Fluorescence
Intersystem crossing
medicine
Instrumentation
Spectroscopy
Fluoroquinolones
medicine.drug
Subjects
Details
- ISSN :
- 13861425
- Volume :
- 133
- Database :
- OpenAIRE
- Journal :
- Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
- Accession number :
- edsair.doi.dedup.....4f99ccb500e2d939b4c5c0483643578b