The photochemistry of N-acetyl-para-aminophenol (acetaminophen, APAP) is here investigated by using differential pulse voltammetry (DPV) analysis to monitor APAP photodegradation upon steady-state irradiation. The purpose of this work is to assess the applicability of DPV to monitor the photochemical behaviour of xenobiotics, along with the development of an electrochemical set-up for the real-time monitoring of APAP photodegradation. We here investigated the APAP photoreactivity towards the main photogenerated reactive transients species occurring in sunlit surface waters (hydroxyl radical HO

, carbonate radical CO₃⁻, excited triplet state of anthraquinone-2-sulfonate used as proxy of the chromophoric DOM, and singlet oxygen ¹O₂), and determined relevant kinetic parameters. A standard procedure based on UV detection coupled with liquid chromatography (HPLC-UV) was used under identical experimental conditions to compare and verify the DPV-based results. The latter were in agreement with HPLC data, with the exception of the triplet-sensitized processes. In the other cases, DPV could be used as an alternative to the well-tested but more costly and time-consuming HPLC-UV technique. We have also assessed the reaction rate constant between APAP and HO by real-time DPV, which allowed for the monitoring of APAP photodegradation inside the irradiation chamber. Unfortunately, real-time DPV measurements are likely to be affected by temperature variations of the irradiated samples. Overall, DPV appeared as a fast, cheap and reasonably reliable technique when used for the off-line monitoring of APAP photodegradation. When a suitable real-time procedure is developed, it could become a very straightforward method to study the photochemical behaviour of electroactive xenobiotics.

中文翻译：

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电化学传感器离线实时监测对乙酰氨基酚的光降解

N-乙酰基-对氨基苯酚（对乙酰氨基酚，APAP）的光化学在这里通过使用差分脉冲伏安法（DPV）分析来监测稳态辐照下APAP的光降解。这项工作的目的是评估DPV在监测异种生物的光化学行为方面的适用性，以及用于实时监测APAP光降解的电化学装置的开发。我们在这里调查了APAP对在阳光照射下的地表水中发生的主要光生反应瞬态物种的光反应性（羟基自由基HO

，碳酸盐自由基CO ₃^-，将蒽醌-2-磺酸盐的激发三重态作为发色DOM的代用品和单线态氧¹ O ₂），并确定了相关的动力学参数。在相同的实验条件下，使用基于UV检测和液相色谱（HPLC-UV）的标准程序来比较和验证基于DPV的结果。后者与HPLC数据一致，但三重态敏化的过程除外。在其他情况下，DPV可以替代经过良好测试但更昂贵，更耗时的HPLC-UV技术。我们还评估了APAP和HO之间的反应速率常数通过实时DPV，可以监控照射室内的APAP光降解。不幸的是，实时DPV测量可能会受到辐照样品温度变化的影响。总的来说，DPV用于离线监测APAP光降解时，它是一种快速，廉价且合理可靠的技术。当开发出合适的实时程序时，它可能成为研究电活性异质生物的光化学行为的一种非常简单的方法。