Development of a highly selective near-infrared fluorescent probe for sensitive detection of Hg²⁺ in environmental...

Mercury ions (Hg²⁺), as highly toxic heavy metals, severely threatened environmental and biological health. Herein, we reported a near-infrared fluorescent probe (DHC) for selective Hg²⁺ sensing. This probe, after reacting with Hg²⁺, featured an emission wavelength of 650 nm and enabled detection with a limit of 0.1 μM. It showed a rapid response in complex matrices, displaying outstanding selectivity and sensitivity. It resisted interference from various metal cations (such as Fe^3＋, Cu²⁺, and Ag⁺), anions (including HS^-, ONOO^-, and Cl^-), and amino acids (e.g., Val, Glu, and Trp). It supported RGB smartphone detection, which enabled intuitive visualization and quantitative analysis of Hg²⁺ distribution through color changes-particularly facilitating rapid detection in cotton swabs and test strips and played a crucial role in detection in the fields of food and water samples. Furthermore, endowed with excellent biocompatibility, it was successfully applied to mercury ion imaging in Huh7 cells, extending its utility to biological systems. This work provided crucial technical support for environmental toxicology research and early clinical diagnosis.