College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, China.
Jiangxi Agricultural Technology Extension Center, Nanchang 330046, China.
Int J Mol Sci. 2023 Jun 23;24(13):10521. doi: 10.3390/ijms241310521.
Florpyrauxifen-benzyl is a novel herbicide used to control weeds in paddy fields. To clarify and evaluate its hydrolytic behavior and safety in water environments, its hydrolytic characteristics were investigated under varying temperatures, pH values, initial mass concentrations and water types, as well as the effects of 40 environmental factors such as microplastics (MPs) and disposable face masks (DFMs). Meanwhile, hydrolytic products were identified by UPLC-QTOF-MS/MS, and its hydrolytic pathways were proposed. The effects of MPs and DFMs on hydrolytic products and pathways were also investigated. The results showed that hydrolysis of florpyrauxifen-benzyl was a spontaneous process driven by endothermic, base catalysis and activation entropy increase and conformed to the first-order kinetics. The temperature had an obvious effect on hydrolysis rate under alkaline condition, the hydrolysis reaction conformed to Arrhenius formula, and activation enthalpy, activation entropy, and Gibbs free energy were negatively correlated with temperature. Most of environmental factors promoted hydrolysis of florpyrauxifen-benzyl, especially the cetyltrimethyl ammonium bromide (CTAB). The hydrolysis mechanism was ester hydrolysis reaction with a main product of florpyrauxifen. The MPs and DFMs did not affect the hydrolytic mechanisms but the hydrolysis rate. The results are crucial for illustrating and assessing the environmental fate and risks of florpyrauxifen-benzyl.
氟吡草腙苄基是一种新型除草剂，用于水田杂草防治。为阐明和评估其在水环境中的水解行为和安全性，在不同温度、pH 值、初始质量浓度和水类型以及微塑料 (MPs) 和一次性口罩 (DFMs) 等 40 种环境因素的影响下，研究了其水解特性。同时，通过 UPLC-QTOF-MS/MS 鉴定了水解产物，并提出了其水解途径。还研究了 MPs 和 DFMs 对水解产物和途径的影响。结果表明，氟吡草腙苄基的水解是一个自发的过程，由吸热、碱催化和活化熵增加驱动，符合一级动力学。在碱性条件下，温度对水解速率有明显影响，水解反应符合阿仑尼乌斯公式，活化焓、活化熵和吉布斯自由能与温度呈负相关。大多数环境因素都促进了氟吡草腙苄基的水解，尤其是十六烷基三甲基溴化铵（CTAB）。水解机制是酯水解反应，主要产物为氟吡草腙。MPs 和 DFMs 不影响水解机制，但影响水解速率。研究结果对于阐明和评估氟吡草腙苄基的环境归宿和风险具有重要意义。
