A dihydroxanthene-based ratiometric fluorescent probe for ultrasensitive and rapid detection of Hg2+ and its applications

Mercury ions (Hg 2+ ) are highly hazardous environmental pollutants that pose significant risks to human health and can cause severe illnesses, making their careful detection essential. Herein, we report a novel dihydroxanthene-based fluorescent probe (E)-4-(1,3-dithiolan-2-yl)-7-styryl-2,3-dihydro-1H-xanthene ( SDHX-DT ) for Hg 2+ detection. Upon interaction with Hg 2+ , SDHX-DT undergoes desulfurization, leading to a ratiometric fluorescence shift and a distinct visible color transformation from blue to green. The recognition mechanism for Hg 2+ has been fully confirmed through UV–vis, fluorescence spectroscopy, 1 H NMR, and HRMS analysis. SDHX-DT demonstrates outstanding sensing performance, featuring exceptional selectivity for Hg 2+ , strong anti-interference capability, a fast response time (< 3 min), a large Stokes shift (162 nm), and ultra-sensitivity with a detection limit of 0.62 nM. Moreover, the probe's excellent properties enable diverse practical applications, such as the convenient and portable detection of Hg 2+ using test strips, reliable monitoring in real environmental water samples, and high-contrast fluorescence imaging in living cells.