A simple fluorescent probe for detection of Ag and Cd and its Cd complex for sequential recognition of S.

In this study, we designed and synthesized a simple probe 2-(8-((8-methoxyquinolin-2-yl)methoxy)quinolin-2-yl)benzo[]thiazole (DQT) for detection of Ag and Cd in a CHOH/HEPES (9 : 1 v/v, pH = 7.30) buffer system. Its structure was characterized by NMR, ESI-HR-MS and DFT calculations, and its fluorescence performance was also investigated. Probe DQT showed fluorescence quenching in response to Ag and Cd with low detection limits of 0.42 μM and 0.26 μM, respectively. Importantly, the complexation of the probe with Cd resulted in a red shift from blue to green, making it possible to detect Ag and Cd by the naked eye under an ultraviolet lamp. The DQT-Cd complex could be used for sequential recognition of S. The recovery response could be repeated 3 times by alternate addition of Cd and S. A filter paper strip test further demonstrated the potential of probe DQT as a convenient and rapid assay.