Hou Jingzhou, Wang Xianfeng, Lan Shiyu, Zhang Chao, Hou Changjun, He Qiang, Huo Danqun
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, PR China.
Anal Methods. 2020 Sep 7;12(33):4130-4138. doi: 10.1039/d0ay01241f. Epub 2020 Aug 7.
Carbon dots (CDs) having low cost and low toxicity and synthesized via a green route were applied to establish a fluorescent nanoprobe for the measurement of glyphosate. The synthesis was realized via a one-pot hydrothermal procedure using Sophora japonica leaves as the carbon source. It was found that electron transfer occurred between Fe and the as-prepared CDs. Therefore, Fe exhibited a specific dynamic-quenching toward CDs. However, the electron transfer process was inhibited by glyphosate. The fluorescence of the quenched CDs/Fe system was recovered by the addition of glyphosate. It resulted from the strong complexation between Fe and the functional groups (like -POH and -COOH) in the glyphosate molecule. These functional groups captured Fe from the CD/Fe system to reduce the electron transfer. With such a design, the rapid detection of glyphosate could be realized by this turn-on fluorescent sensor based on the CD/Fe system. Under optimal conditions, the CD/Fe system showed a concentration-dependent fluorescent response toward glyphosate in the linear range from 0.1 to 16 ppm. The limit of detection was calculated to be as low as 8.75 ppb (3σ/S). In addition, the successful detection of glyphosate in real samples with satisfactory recoveries exhibited a practical application of the CD/Fe nanoprobe in food safety and environmental monitoring.
通过绿色路线合成的具有低成本和低毒性的碳点（CDs）被用于构建一种用于测定草甘膦的荧光纳米探针。该合成通过一锅水热法实现，使用槐树叶作为碳源。研究发现，铁（Fe）与制备好的碳点之间发生了电子转移。因此，铁对碳点表现出特定的动态猝灭作用。然而，草甘膦抑制了电子转移过程。加入草甘膦后，猝灭的碳点/铁体系的荧光得以恢复。这是由于铁与草甘膦分子中的官能团（如 -POH 和 -COOH）之间存在强烈的络合作用。这些官能团从碳点/铁体系中捕获铁，从而减少电子转移。基于这样的设计，基于碳点/铁体系的这种开启式荧光传感器能够实现草甘膦的快速检测。在最佳条件下，碳点/铁体系对草甘膦在 0.1 至 16 ppm 的线性范围内呈现浓度依赖性荧光响应。计算得出检测限低至 8.75 ppb（3σ/S）。此外，在实际样品中成功检测到草甘膦且回收率令人满意，这表明碳点/铁纳米探针在食品安全和环境监测方面具有实际应用价值。
