Smartphone-assisted ratiometric fluorescence sensor based on NS-codoped carbon dots/Au nanoclusters for rapid detection of Hg2+

Mercury metal can be absorbed into human body through the food chain, and cause considerable harm to human health. Herein, a novel smartphone-enabled ratiometric fluorescence sensing system, which was made up of nitrogen-sulfur co-doped carbon dots (NSCDs) and Au nanoclusters (AuNCs), had developed for rapid detection of mercury ion (Hg 2+ ). The NSCDs/AuNCs displayed dual-emission fluorescence at 406/690 nm. After introducing Hg 2+ , the fluorescence at 690 nm was obviously quenched, while the signal around 406 nm was slightly attenuated, causing a color change from pink-purple to blue. Under the most suitable conditions, the ratiometric fluorescence probe had two linear ranges of 0.05–3.0 and 3.0–7.0 μM with a low limit of detection (LOD) of 18 nM. The approach was utilized to detect Hg 2+ in real water samples. Furthermore, a portable smartphone-assisted sensing platform based on NSCDs/AuNCs provides a simple, affordable, and efficient method for monitoring Hg 2+ in the environments and other fields.