Abstract：
The fluoroquinolones ciprofloxacin, danofloxacin, enoxacin, levofloxacin and lomefloxacin, occur in water bodies worldwide and therefore pose a threat to the aquatic environment. Advanced purification procedures, such as electrochemical oxidation, may act as a remedy since they contribute to eliminating contaminants and prevent micropollutants from entering open water bodies. By electrochemical treatment in a micro-flow reactor equipped with a boron-doped diamond (BDD) electrode, the fluoroquinolones were efficiently degraded. A total of 15 new products were identified using high-performance high-resolution chromatography coupled with high-resolution multifragmentation mass spectrometry. The ecotoxicity of the emerging transformation products was estimated through in silico quantitative structure activity relationship analysis. Almost all transformation products were predicted less ecotoxic than the initial compounds. The fluoroquinolone degradation followed three major mechanisms depending on the voltage during the electrochemical oxidation. At approximately 1 V, the reactions started with the elimination of molecular hydrogen from the piperazine moiety. At approx. 1.25 V, methyl and methylene groups were eliminated. At 1.5 V, hydroxyl radicals, generated at the BDD electrode, led to substitution at the piperazine ring. This novel finding of the three reactions depending on voltage contributes to the mechanistic understanding of electrochemical oxidation as potential remedy against fluoroquinolones in the aquatic environment.
摘要：
氟喹诺酮环丙沙星，达诺沙星,依诺沙星,左氧氟沙星和洛美沙星，发生在世界各地的水体中，因此对水生环境构成威胁。先进的净化程序，如电化学氧化，可以作为一种补救措施，因为它们有助于消除污染物并防止微污染物进入开放水体。通过在配备有掺硼金刚石（BDD）电极的微流反应器中进行电化学处理，氟喹诺酮类药物被有效降解。使用高效高分辨率色谱和高分辨率多片段质谱共鉴定出15种新产品。通过硅片定量构效关系分析，估算了新兴转化产物的生态毒性。预测几乎所有转化产物的生态毒性均低于初始化合物。取决于电化学氧化过程中的电压，氟喹诺酮降解遵循三种主要机制。在大约1V时，反应开始于从哌嗪部分消除分子氢。大约在。1.25V,甲基和亚甲基被消除。在1.5V时，羟基自由基，在BDD电极处产生，导致哌嗪环上的取代。取决于电压的三个反应的新发现有助于对电化学氧化作为水生环境中氟喹诺酮类药物的潜在补救措施的机理理解。
