Jose Joel, Nandhana Lakshmi, Varghese Merlin Elsa, John Nebu
The Post Graduate and Research Department of Chemistry, Mar Thoma College, Tiruvalla, 689103, Kerala, India.
J Fluoresc. 2025 May 21. doi: 10.1007/s10895-025-04342-7.
Sensors that are handy for the common man are highly demanded. Unfortunately, fluorescence sensors alone cannot satisfy this need. Hence here we introduce a dual mode foolproof sensor based on glutathione stabilized copper nanoclusters (GSH-CuNCs) for sensing mercuric ion (Hg), that can combine the features of both worlds, that is the handiness of a colorimetric sensor and the ultra-sensitivity of a fluorescence sensor. On exciting at 300 nm, GSH-CuNCs gave fluorescence emission at 450 nm with a stokes shift of 150 nm and the emission was dependent of excitation wavelength. GSH-CuNCs was characterized using UV-visible spectroscopy, Photoluminescence (PL), Fourier Transform Infrared Spectroscopy (FTIR), Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI TOF), Transmission Electron Microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Time-Correlated Single Photon Counting studies (TCSPC) studies. It was found that the synthesized probe fits great to serve both as a fluorescence and colorimetric probe in sensing the presence of Hg. Hg caused the quenching of fluorescence of the probe. Ascorbic acid (AsA) was used to turn on the fluorescence of this quenched system. Both quenched (Turn off) and turned on system were also studied by employing PL, TCSPC, TEM and XPS techniques. Colorimetric studies found the change in colour of the probe from light yellow to dark brown. The limit of detection (LoD) of Hg was found to be 161.6 nM fluorometrically and 1.5 µM colorimetrically. LoD of AsA was found to be 39.17 nM fluorometrically. This work outshines other similar dual mode sensing techniques for Hg in having simple synthesis and sensing strategy with almost similar sensitivity and selectivity. The feasibility of this sensing strategy to be embedded in complex logic devices for multiplex analysis has also been explored.
普通大众对方便易用的传感器有很高的需求。不幸的是，仅靠荧光传感器无法满足这一需求。因此，在此我们介绍一种基于谷胱甘肽稳定的铜纳米团簇（GSH-CuNCs）的双模式可靠传感器，用于检测汞离子（Hg），它可以结合两种传感器的特性，即比色传感器的便利性和荧光传感器的超灵敏度。在300 nm激发下，GSH-CuNCs在450 nm处发出荧光，斯托克斯位移为150 nm，且发射依赖于激发波长。使用紫外可见光谱、光致发光（PL）、傅里叶变换红外光谱（FTIR）、基质辅助激光解吸电离飞行时间（MALDI TOF）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）、时间相关单光子计数研究（TCSPC）对GSH-CuNCs进行了表征。结果发现，合成的探针非常适合同时作为荧光和比色探针来检测Hg的存在。Hg导致探针荧光猝灭。抗坏血酸（AsA）用于开启该猝灭系统的荧光。还通过PL、TCSPC、TEM和XPS技术研究了猝灭（关闭）和开启系统。比色研究发现探针颜色从浅黄色变为深棕色。Hg的检测限荧光法为161.6 nM，比色法为1.5 μM。AsA的检测限荧光法为39.17 nM。这项工作在Hg的双模式传感技术方面表现出色，具有简单的合成和传感策略，灵敏度和选择性几乎相似。还探索了这种传感策略嵌入复杂逻辑器件进行多重分析的可行性。
