Despite the frequent detection of fluorinated liquid-crystal monomers (FLCMs) in the environment, the level of understanding of their fate, toxicity, and transformation remains insufficient. Herein, we investigated the degradation kinetics and mechanism of an FLCM (4-cyano-3-fluorophenyl 4-ethylbenzoate, CEB-F) under ultraviolet (UV) photolysis in aquatic environment. Our findings demonstrated that the UV photolysis of CEB-F followed first-order kinetics. Photodegradation products were identified using liquid chromatography with mass spectrometry, and detailed reaction pathways were proposed. It is postulated that through the attack of reactive oxygen species, hydroxylation, and CO/C-F bond cleavage, CEB-F gradually degraded into small molecular compounds, releasing fluorine ions. Acute immobilization tests with () revealed significant acute toxicity of CEB-F, with LC values ranging from 1.023 to 0.0536 μM over 24 to 96 h, emphasizing the potential high risk of FLCMs in aquatic ecosystems if inadvertently discharged. Interestingly, we found that the toxicity of CEB-F photolysis reaction solutions was effectively reduced. Through catalase and acetylcholinesterase activities analysis along with molecular docking simulation, we proposed differences in the underlying toxicity mechanisms of CEB-F and its photolysis products to . These findings highlight the potential harmful effects of FLCMs on aquatic ecosystems and enrich our understanding of the photolysis behavior of FLCMs.

中文翻译：

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高风险氟化液晶单体的水生光解：动力学、毒性评估和机制

尽管在环境中经常检测到氟化液晶单体（FLCM），但对其命运、毒性和转化的了解仍然不足。在此，我们研究了 FLCM（4-氰基-3-氟苯基 4-乙基苯甲酸酯，CEB-F）在水生环境中紫外（UV）光解作用下的降解动力学和机理。我们的研究结果表明，CEB-F 的紫外光解遵循一级动力学。使用液相色谱和质谱法鉴定光降解产物，并提出了详细的反应途径。推测通过活性氧的攻击、羟基化和CO/CF键断裂，CEB-F逐渐降解为小分子化合物，释放出氟离子。 () 的急性固定测试显示，CEB-F 具有显着的急性毒性，24 至 96 小时内的 LC 值范围为 1.023 至 0.0536 μM，强调了如果不慎排放，水生生态系统中 FLCM 的潜在高风险。有趣的是，我们发现CEB-F光解反应溶液的毒性得到了有效降低。通过过氧化氢酶和乙酰胆碱酯酶活性分析以及分子对接模拟，我们提出了CEB-F及其光解产物对 的潜在毒性机制的差异。这些发现强调了 FLCM 对水生生态系统的潜在有害影响，并丰富了我们对 FLCM 光解行为的理解。