Onishi Bruno S D, Carneiro Neto Albano N, Ribeiro Sidney J L
Institute of Chemistry, São Paulo State University-UNESP, São Paulo, Araraquara 14800-060, Brazil.
Physics Department and CICECO - Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
ACS Omega. 2024 Dec 17;9(52):51204-51212. doi: 10.1021/acsomega.4c07183. eCollection 2024 Dec 31.
Motivated by the importance of Hg detection in water due to its harmful effect on the environment and human health, we investigated a recently developed nanocomposite based on carbon dots (CDs) and LAPONITE as an optical chemical sensor using photoluminescence emission. While several studies have reported the Hg detection using CDs' photoluminescence emission, there is a lack of in-depth investigation into the quenching mechanisms involved in turn-off sensors. In this study, we propose a Stern-Volmer analysis at three different temperatures (288, 298, and 303 K). The results indicated selectivity for Hg over that of the other evaluated metal. The optimum detection range for Hg was found to be 1-40 μM, with limits of detection and quantification of 2.5 and 8.3 μM, respectively. Using the Stern-Volmer models, we found that static quenching dominates over collisional quenching, possibly due to the complexation between nanocomposite's carboxylate groups and Hg. Additionally, the modified Stern-Volmer model, which accounts for the fractional accessibility of the fluorophores by the quenchers, suggests that some parts of the sensor are inaccessible to the quencher.
由于汞对环境和人类健康具有有害影响，水中汞检测至关重要，在此推动下，我们研究了一种最近开发的基于碳点（CDs）和锂皂石的纳米复合材料，作为利用光致发光发射的光学化学传感器。虽然已有多项研究报道了利用碳点的光致发光发射检测汞，但对于关断型传感器中涉及的猝灭机制缺乏深入研究。在本研究中，我们提出在三个不同温度（288、298和303 K）下进行斯特恩-沃尔默分析。结果表明，该传感器对汞的选择性高于其他评估的金属。发现汞的最佳检测范围为1-40 μM，检测限和定量限分别为2.5和8.3 μM。使用斯特恩-沃尔默模型，我们发现静态猝灭比碰撞猝灭占主导地位，这可能是由于纳米复合材料的羧基与汞之间的络合作用。此外，修正的斯特恩-沃尔默模型考虑了猝灭剂对荧光团的部分可及性，表明传感器的某些部分猝灭剂无法到达。
