Development of a new series of thioacetal based fluorescence chemosensors for highly sensitive determination of Hg2+ in environmental samples and cell imaging.

Mercury ion is one of the most harmful metal ions with significant hazards to the environment and human health. Thus, the development of innovative, sensitive, and selective sensors to help address the detrimental impacts of heavy metal contamination is necessary. In this work, we present three new chemosensors based on the deprotection reaction of the thioacetal group for distinguishing Hg2+ in environmental samples. These chemosensors show good photophysical properties with high quantum yield in aqueous medium. These prepared chemosensors were employed as fluorometric sensors for the determination of Hg2+ through the quenching of fluorescence emission due to the Hg2+-induced hydrolysis of the thioacetal to the aldehyde group. In the presence of Hg2+, chemosensors showed an emissive color transformation from blue fluorescence to non-fluorescence under UV light, which was readily seen by the visual eye. These chemosensors also exhibited highly distinctive selectivity toward Hg2+ over other interfering metal ions, with detection limits of 1.1 ppb, 13.4 ppb, and 12.7 ppb. Moreover, the practical applicability of chemosensor was successfully demonstrated in real water samples and herb extract samples.