Electro-Fenton-like processes are widely used in removal of antibiotics in sewage owing to their excellent degradation efficiency for organics. However, the degradation mechanisms of antibiotics in electro-Fenton-like systems are still unclear caused by the non-real time detection of current methods. An electrochemical-mass spectrometry (EC-MS) method was developed for in situ analysis and real-time monitoring of electrochemical degradation of antibiotics in this study. In EC-MS, ITO glass was used as an electrochemical reactor and counter electrode, which is positioned in front of the MS inlet. A platinum slice as a working electrode was placed over the ITO glass. When different high voltages were applied on the electrodes, the electrochemical degradation of organics started and a charged spray was generated for MS detection. To enhance the electrochemical reaction efficiency, the voltage difference was optimized. As a proof-of-concept, the degradation of ciprofloxacin (CIP) in an electro-Fenton-like system was monitored, and five intermediates (m/z 330, 304, 348, 346 and 362) different from those obtained in other removal processes were detected and verified. Furthermore, six new characteristic intermediates (m/z 364, 305, 293, 277, 275 and 280) were captured. Meanwhile, the compounds were identified by high-resolution mass spectrometry and tandem mass spectrometry. Extracted ion chromatography (EIC) of several characteristic intermediates was performed for further discussion of the degradation pathway. Based on the data acquired, the degradation mechanism of CIP by an electro-Fenton-like process was proposed for the first time. This work provided a useful tool for mechanism research in electrochemical advanced oxidation processes.

中文翻译：

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使用电化学质谱法实时监测类芬顿电系统中环丙沙星降解

类似于电子芬顿的工艺因其对有机物的出色降解效率而广泛用于去除污水中的抗生素。然而，由于目前方法的非实时检测，导致在类似电子芬顿系统中的抗生素降解机理仍不清楚。电化学质谱法（EC-MS）被开发用于原位本研究对抗生素的电化学降解进行分析和实时监测。在EC-MS中，ITO玻璃用作电化学反应器和对电极，位于MS入口的前面。将铂片作为工作电极放置在ITO玻璃上。当在电极上施加不同的高压时，有机物开始发生电化学降解，并生成带电喷雾以进行MS检测。为了提高电化学反应效率，优化了电压差。作为概念验证，在类似电子芬顿的系统中监测环丙沙星（CIP）的降解，并检测五个中间体（m / z检测并验证了与其他去除过程中获得的结果不同的330、304、348、346和362）。此外，还捕获了六个新的特征中间体（m / z 364、305、293、277、275和280）。同时，通过高分辨率质谱和串联质谱对化合物进行鉴定。进行了几种特征中间体的萃取离子色谱法（EIC），以进一步讨论降解途径。基于获得的数据，首次提出了通过类电子芬顿法降解CIP的机理。这项工作为电化学高级氧化过程的机理研究提供了有用的工具。