Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
Environ Sci Technol. 2020 Mar 17;54(6):3325-3333. doi: 10.1021/acs.est.9b07304. Epub 2020 Feb 27.
In this study, we reveal the capacity of imidacloprid (a neonicotinoid insecticide) to photoinduce the nitration and nitrosation of three aromatic probes (phenol, resorcinol, and tryptophan) in water. Using a gas-flow reactor and a NO analyzer, the production of gaseous NO/NO was demonstrated during irradiation (300-450 nm) of imidacloprid (10 M). Quantum calculations showed that the formation of NO proceeds via homolytic cleavage of the RN-NO bond in the triplet state. In addition to gaseous NO/NO, nitrite and nitrate were also detected in water, with the following mass balance: 40 ± 8% for NO, 2 ± 0.5% for NO, 52 ± 5% for NO, and 16 ± 2% for NO. The formation of nitro/nitroso probe derivatives was evidenced by high-resolution mass spectrometry, and their yields were found to range between 0.08 and 5.1%. The contribution of NO/NO to the nitration and nitrosation processes was found to be minor under our experimental conditions. In contrast, the addition of natural organic matter (NOM) significantly enhanced the yields of nitro/nitroso derivatives, likely via the production of triplet excited states (NOM*) and HO. These findings reveal the importance of investigating the photochemical reactivity of water contaminants in a mixture to better understand the cocktail effects on their fate and toxicity.
在这项研究中，我们揭示了吡虫啉（一种新烟碱类杀虫剂）在水中光诱导三种芳香探针（苯酚、间苯二酚和色氨酸）硝化和亚硝化的能力。使用气流反应器和 NO 分析仪，在吡虫啉（10M）辐照（300-450nm）期间证明了气态 NO/NO 的产生。量子计算表明，NO 的形成是通过三重态中 RN-NO 键的均裂进行的。除了气态 NO/NO 之外，水中还检测到亚硝酸盐和硝酸盐，其质量平衡如下：NO 为 40±8%，NO 为 2±0.5%，NO 为 52±5%，NO 为 16±2%。高分辨率质谱证实了硝基/亚硝基探针衍生物的形成，其产率在 0.08 至 5.1%之间。在我们的实验条件下，NO/NO 对硝化和亚硝化过程的贡献较小。相比之下，天然有机物（NOM）的添加显著提高了硝基/亚硝基衍生物的产率，这可能是通过产生三重态激发态（NOM*和 HO）实现的。这些发现揭示了在混合物中研究水污染物光化学反应的重要性，以便更好地理解其命运和毒性的鸡尾酒效应。
