Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) - ENSCCF, BP 10448, F-63000 Clermont-Ferrand, France.
Water Res. 2013 Sep 15;47(14):5422-30. doi: 10.1016/j.watres.2013.06.024. Epub 2013 Jun 21.
In this paper we investigated the degradation of the rivastigmine drug induced by hydroxyl radical in synthetic and natural waters focusing on both reactivity and photoproducts identification. The hydroxyl radical formation rate was quantified by using terephthalic acid as trapping molecule and it was related with the rivastigmine degradation rate. The second order rate constant between hydroxyl radical and rivastigmine was estimated to be ≈ 5.8 × 10(9) M(-1) s(-1). Irradiation of rivastigmine in three natural waters (rain, lake and river) and comparison with degradation rates observed in synthetic solutions using nitrite, nitrate and hydrogen peroxide suggest that, in addition to hydroxyl radical, also nitroderived radicals (NO/NO2) are responsible for the pollutant degradation in natural media. In fact, the evaluated degradation rates in three natural waters are greatly higher than those estimated considering only the reactivity with photogenerated hydroxyl radical. Using nitrites and nitrates as photochemical OH source, the rivastigmine degradation cannot be described considering only the hydroxyl radical reactivity suggesting that NO and NO2 radicals could play a key role during indirect degradation. Moreover main degradation products have been identified by means of HPLC-MS. Hydroxylation of the aromatic ring as well as carbamate and amino chain oxidation were suggested as main reaction mechanisms, but also nitroderived compounds were characterized. Finally polychromatic irradiations of three rivastigmine doped natural waters (rain, river and lake) underlined the role of the indirect degradation that needs to be considered when direct degradation of selected pollutants is negligible under environmental-like conditions.
在本文中，我们研究了在合成水和天然水中，羟自由基诱导的rivastigmine 药物的降解，重点关注反应性和光产物的鉴定。通过使用对苯二甲酸作为捕获分子来量化羟基自由基的形成速率，并将其与 rivastigmine 的降解速率相关联。羟基自由基与 rivastigmine 之间的二级反应速率常数估计约为 5.8×10(9) M(-1) s(-1)。在三种天然水中（雨水、湖水和河水）对 rivastigmine 进行辐照，并与在合成溶液中使用亚硝酸盐、硝酸盐和过氧化氢观察到的降解速率进行比较，表明除了羟基自由基外，硝基衍生自由基（NO/NO2）也负责天然介质中污染物的降解。事实上，在三种天然水中评估的降解速率远高于仅考虑与光生成的羟基自由基反应性所估计的值。使用亚硝酸盐和硝酸盐作为光化学 OH 源，rivastigmine 的降解不能仅考虑羟基自由基的反应性来描述，这表明 NO 和 NO2 自由基在间接降解过程中可能发挥关键作用。此外，还通过 HPLC-MS 鉴定了主要降解产物。提出了芳环的羟化以及氨基甲酸酯和氨基链的氧化作为主要反应机制，但也对硝基衍生化合物进行了表征。最后，对三种 rivastigmine 掺杂天然水（雨水、河水和湖水）进行多色辐照，强调了间接降解的作用，在环境相似条件下，当选定污染物的直接降解可以忽略不计时，需要考虑间接降解。
