Concentration-dependent photodegradation kinetics and hydroxyl-radical oxidation of phenicol antibiotics

Li, Kai; Zhang, Peng; Ge, Liang; Ren, Honglei; Yu, Chunyan; Chen, Xiaoyang; Yuan-feng, Zhao

doi:10.1016/j.chemosphere.2014.04.052

Cited by 44 publications

(16 citation statements)

References 35 publications

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“…Compared to the environmental apparent photolysis half-lives (Table 1), the t•OH,E values are 1 -2 orders of magnitude higher, suggesting that this is not the dominant loss pathway for the FQs. However, the hydroxyl-radical oxidation is expected to be more effective at inducing the degradation of FQs due to the lower selectivity of •OH, which can oxidize almost all classes of organic chemicals (Ge et al, 2015) (Keen and Linden, 2013;Li et al, 2014;Mill, 1999).…”

Section: Hydroxyl-radical Oxidation Kinetics Of Different Dissociatiomentioning

confidence: 99%

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Halsall

Chen

et al. 2018

Science of The Total Environment

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Fluoroquinolone antibiotics (FQs) are ubiquitous and ionisable in surface waters. Here we investigate gatifloxacin (GAT) and balofloxacin (BAL), two widely used FQs, and determine the photochemical reactivity of their respective dissociation species that arise at different pH to understand the relevance and pathways of phototransformation reactions. Simulated-sunlight experiments and matrix calculations showed that neutral forms (HFQs) of the two antibiotics had the highest apparent photolytic efficiency and hydroxyl-radical oxidation reactivity. Based on the pH-dependent photochemical reactivities, the solar apparent photodegradation half-lives (t) in sunlit surface waters ranged from 14.5-169min and was 1-2 orders of magnitude faster than hydroxyl-radical induced oxidation (t=20.9-29.8h). The corresponding pathways were proposed based on the identification of key intermediates using HPLC-ESI-MS/MS. The apparent photodegradation induced defluorination, decarboxylation, and piperazinyl oxidation and rearrangement, whereas hydroxyl-radical oxidation caused hydroxylated defluorination and piperazinyl hydroxylation. The photomodified toxicity of GAT and BAL was examined using an Escherichia coli activity assay. E. coli activity was not affected by BAL, but was significantly affected by the photo-modified solutions of GAT, indicating that primary photo-degradates have a comparable or higher antibacterial activity than the parent GAT. In fresh water and seawater this antibacterial activity remained high for up to 24h, even after GAT had undergone significant photodegradation (>1 half-life), indicating the potential impact of this chemical on microbial communities in aquatic systems.

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Section: Hydroxyl-radical Oxidation Kinetics Of Different Dissociatiomentioning

confidence: 99%

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Halsall

Chen

et al. 2018

Science of The Total Environment

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“…Kinetic analysis of degradation profiles followed first-order or pseudo first-order kinetic models, consecutive and subsequent follow-up reaction models, cf. Equation (1), according to previous studies and theory [26,[32][33][34][35][36][37]. The complete kinetic description is represented in the Supplementary Information.…”

Section: Kinetic Analysis and Determination Of Quantum Efficiency Of mentioning

confidence: 99%

Lomefloxacin—Occurrence in the German River Erft, Its Photo-Induced Elimination, and Assessment of Ecotoxicity

et al. 2020

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Pharmaceuticals in waters represent a worldwide problem of today. Advanced oxidation processes (AOPs) are being researched for elimination of the ecological hazard. Among the substances, the fluoroquinolone antibiotic lomefloxacin was selected for investigation in this study. Lomefloxacin (LOM) was found in the German river Erft. Near and far ultraviolet (UVA, UVC) radiation were used as AOPs and compared for efficiency depending on pH, water matrix, and catalysts. Chemical kinetics description revealed that UVC at pH 8-9 led to the fastest degradation of LOM. The catalysts hydrogen peroxide and titanium dioxide had only limited influence on the degradation rate. Seven novel transformation products were structurally identified by high-resolution higher-order mass spectrometry. Ecotoxicity of the novel and known compounds was assessed by quantitative structure-activity relationship (QSAR) analysis. In addition, irradiation time dependent minimal, and half-maximal inhibitory concentrations (MIC, IC 50 ) of LOM solutions were determined and suggested as ecotoxicological hazard indicators. From MIC and kinetic rate constants, the irradiation time required for compound and activity removal could be predicted.

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“…1, an increase in initial ENO concentration resulted in a proportional decrease in the corresponding specific ENO photolysis rates. Li et al (2014) investigated the effect of the initial concentration on the photodegradation kinetics and hydroxyl radicaldriven oxidation of thiamphenicol and florfenicol. They found that these antibiotics under direct photolysis and selfsensitized photo-oxidation were rapidly removed and the slopes of the corresponding k vs. C 0 plots were negative.…”

Section: Eno Photolysis: Effect Of Initial Concentrationmentioning

confidence: 99%

Direct and indirect photolysis of the antibiotic enoxacin: kinetics of oxidation by reactive photo-induced species and simulations

Lastre-Acosta

Barberato

Parizi

et al. 2018

Environ Sci Pollut Res

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The purpose of this study was to investigate the aqueous phase photochemical behavior of enoxacin (ENO), an antibiotic selected as a model pollutant of emerging concern. The second-order reaction rate constants of ENO with hydroxyl radicals (HO) and singlet oxygen (O) were determined at pH 3, 7, and 9. Also, the rate constants of the electron transfer reaction between ENO and triplet states of chromophoric dissolved organic matter (CDOM*) are reported for the first time, based on anthraquinone-2-sulfonate (AQ2S) as CDOM proxy. The sunlight-driven direct and indirect ENO degradation in the presence of dissolved organic matter (DOM) is also discussed. The results show that direct photolysis, which occurs more rapidly at higher pH, along with the reactions with HO and AQ2S*, is the key pathway involved in ENO degradation. The ENO zwitterions, prevailing at pH 7, show k HO, k, and k of (14.0 ± 0.8) × 10, (3.9 ± 0.2) × 10, and (61.5 ± 0.7) × 10 L mol s, respectively, whose differences at pH 3, 7, and 9 are due to ENO pH-dependent speciation and reactivity. These k values, along with the experimental ENO photolysis quantum yield, were used in mathematical simulations for predicting ENO persistence in sunlit natural waters. According to the simulations, dissolved organic matter and water depth are expected to have the highest impacts on ENO half-life, varying from a few hours to days in summertime, depending on the concentrations of relevant waterborne species (organic matter, NO, NO, HCO).

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Concentration-dependent photodegradation kinetics and hydroxyl-radical oxidation of phenicol antibiotics

Cited by 44 publications

References 35 publications

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Lomefloxacin—Occurrence in the German River Erft, Its Photo-Induced Elimination, and Assessment of Ecotoxicity

Direct and indirect photolysis of the antibiotic enoxacin: kinetics of oxidation by reactive photo-induced species and simulations

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