A Coumarin-Based Fluorescent Probe for Ratiometric Monitoring of Hg2+ in Live Cells

A new ultrasensitive ratiometric fluorescent probe for the monitoring of mercury ions via specific mercury-triggered desulfurization of dithioacetal has been judiciously developed. This probe (MS5) exhibits an efficient fluorescence and color response toward Hg2+ in aqueous solution. Its excellent selectivity, visible light emission (450–650 nm), low detection limit (∼0.81 ppb), and fast response kinetics (within 30 s) make it better than most reported ones. More importantly, this probe (MS5) has also been smoothly applied to ratiometrically imaging Hg2+ in live HeLa cells.