Intelligent multicolor nano-sensor based on nontoxic dual fluoroprobe and MOFs for colorful consecutive detection of Hg and cysteine.

Ultrasensitive detection of Hg in aquatic ecosystems is of great significance due to its high toxicity and ubiquity in water. Herein, using a one-step in-situ synthesis method, blue fluorescent carbon dots (CDs), red fluorescent InP/ZnS quantum dots (InPQDs), and MOFs (ZIF-8) integrated multicolor nano-sensor CDs/InPQDs@ZIF-8 was constructed for consecutive visual detection of Hg and Cys. The InPQDs can act as the response unit for Hg and Cys, with the limit of detection (LOD) of 8.68 and 37.96 nM, respectively. Significantly, the low detection limit combines with good specificity and accuracy of the nano-sensor meet the requirement for the safety monitoring and control of Hg in drinking and environmental water. Moreover, the color recognition and processing software installed on smart phone can realize the real-time and rapid sensing of Hg and Cys. A logic gate circuit was also devised, providing the possibilities for the application of the nano-sensor in the field of intelligent devices. As far as we know, this was the first example to apply InPQDs to the continuous multicolor visual detection of Hg and Cys, which provided reference for the construction of environmentally-friendly dual emission fluorescent sensors for hazardous substance monitoring.