Quantitative identification of dynamic and static quenching of ofloxacin by dissolved organic matter using temperature-dependent kinetic approach.
Ofloxacin (OFL) was used as a model antibiotic and the quenching of OFL fluorescence by DOM was examined with an emphasis on temperature-dependent quenching kinetics. OFL fluorescence intensity was corrected for inner filter and temperature effects. The kinetics data were fitted well using a two-compartment pseudo first-order kinetics model. Three quenching compartments were identified using this model, namely, a very fast quenching compartment (q(0)) and two pseudo first-order quenching compartments (q(1) + q(2)). The q(0) values had a positive relationship with temperature, while (q(1) + q(2)) were negatively related with temperature. In addition, OFL-DOM binding quantified by (q(1) + q(2)) was consistent with binding result obtained from dialysis equilibrium system. We concluded that q(0) was resulted from dynamic quenching, while (q(1) + q(2)) was attributed to static quenching. The dynamic quenching of OFL by DOM accounted for 30-90% to the overall quenching and thus was very significant.
Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650093, China. panbocai@gmail.com
Bo
B
Pan
Ying
Y
Liu
Di
D
Xiao
Fengchang
F
Wu
Min
M
Wu
Di
D
Zhang
Baoshan
B
Xing
D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry*; D006812:Humic Substances; D007700:Kinetics; D008956:Models, Chemical; D015242:Ofloxacin / Q000032:analysis / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D006812:Humic Substances; D009930:Organic Chemicals; D012987:Soil; D014874:Water Pollutants, Chemical; D015242:Ofloxacin