Degradation of flumequine by the Fenton and photo-Fenton processes: evaluation of residual antimicrobial activity.
Flumequine is a broad-spectrum antimicrobial agent of the quinolone class, and it is widely used as a veterinary drug in food-producing animals. The presence of flumequine in the environment may contribute to the development of drug resistant bacterial strains. In this study, water samples fortified with flumequine (500 μg L(-1)) were degraded using the Fenton and photo-Fenton processes. The maximum degradation efficiency for flumequine by the Fenton process was approximately 40% (0.5 mmol L(-1) Fe(II), 2.0 mmol L(-1) H(2)O(2) and 15 min). By applying UV radiation (photo-Fenton process), the efficiency reached more than 94% in 60 min when 0.25 mmol L(-1) Fe(II) and 10.0 mmol L(-1) H(2)O(2) were used. Under these conditions, the Fenton process was able to reduce the biological activity, whereas the photo-Fenton process eliminated almost all of the antimicrobial activity because it was not detected. Four byproducts with an m/z of 244, 238, 220 and 202 were identified by mass spectrometry, and a degradation pathway for flumequine was proposed. The byproducts were derived from decarboxylation and defluorination reactions and from modifications in the alkylamino chain of the fluoroquinolone.
School of Civil Engineering, Architecture and Urbanism, University of Campinas - UNICAMP, P.O. Box 6021, CEP 13083-852, Campinas, SP, Brazil.
Caio
C
Rodrigues-Silva
Milena Guedes
MG
Maniero
Susanne
S
Rath
José Roberto
JR
Guimarães
D048908:Aliivibrio fischeri / Q000187:drug effects; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D004781:Environmental Exposure; D024841:Fluoroquinolones / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D018675:Toxicity Tests; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
D000890:Anti-Infective Agents; C045076:Fenton's reagent; D024841:Fluoroquinolones; D006861:Hydrogen Peroxide; D007501:Iron; C012976:flumequine