In this work, a coumarin derivative (CND) was synthesized by a one-step condensation reaction and exhibited selective fluorescence quenching by Cu²⁺. Glyphosate with amine and carboxylate groups provided strong chelation for Cu²⁺ from the CND/Cu²⁺ system, leading to fluorescence recovery. In this strategy, a CND/Cu²⁺ fluorescence sensing system was constructed to achieve the quantitative analysis of glyphosate. Under the optimized experimental conditions, a good linear relationship between CND and Cu²⁺ of glyphosate concentration in the range from 0.02 μg mL⁻¹ to 1.50 μg mL⁻¹ was obtained and the correlation coefficient was 0.99. The detection limit was calculated to be 18.30 ng mL⁻¹ (S/N = 3) and presented relative advantages compared with other methods. The interference study exhibited excellent selectivity towards glyphosate. In addition, satisfactory recoveries ranging from 91.31% to 105.28% were achieved for the real samples. These results indicate that the CND/Cu²⁺ fluorescence sensing system has practical application prospects.

中文翻译：

---

用于草甘膦超灵敏检测的CND / Cu2 +荧光传感系统的构建

在这项工作中，香豆素衍生物（CND）是通过一步缩合反应合成的，并通过Cu ²⁺表现出选择性的荧光猝灭。具有胺和羧酸根基团的草甘膦为CND / Cu ²⁺系统中的Cu ²⁺提供了强大的螯合作用，导致了荧光的恢复。在该策略中，构建了CND / Cu ²⁺荧光传感系统以实现草甘膦的定量分析。在优化的实验条件下，草甘膦浓度的CND与Cu ²⁺之间的线性关系良好，范围为0.02μgmL ^-1至1.50μgmL ^-1得到了相关系数为0.99。计算出的检出限为18.30 ng mL ^-1（S / N = 3），与其他方法相比，具有相对优势。干扰研究显示出对草甘膦的优异选择性。此外，实际样品的回收率在91.31％到105.28％之间。这些结果表明，CND / Cu ²⁺荧光传感系统具有实际的应用前景。