CHED 1087 |
| In the interest of determining environmental persistence and impact, the photodegradation of two fluoroquinolone-class antibacterials, norfloxacin and ofloxacin, was studied. Two major norfloxacin photoproducts and one major ofloxacin photoproduct were characterized using a combination of mass spectrometry and NMR data and are expected to be environmentally benign. Previously, we determined that indirect photochemical processes were insignificant for both ofloxacin and norfloxacin and that there is a strong dependence of direct photodegradation rate on pH. Here, photolysis experiments were conducted in deionized water under sunlight at a range of pH. Using decay constants calculated from these photolyses, experimentally determined pKas, and deconvoluted absorbance spectra, direct photolysis quantum yields were calculated for each of three protonation species of each fluoroquinolone. Quantum yields were found to be significantly greater for the species dominant at neutral pH. For this reason, we can predict wide variations in rate of degradation for different natural water bodies. |
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Undergraduate Research Poster Session: Environmental Chemistry
2:00 PM-4:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |