Pratap R.Hassan N.Yadav M.Srivastava S.K.Chaudhary S.Verma A.K.Lahiri J.Parmar A.S.2025-01-132025-01-13202420518153https://dl.bhu.ac.in/ir/handle/123456789/2373Due to the excessive residues and serious adverse effects, it is urgent to develop an efficient method to detect Hg2+ and As3+ in drinking water to protect human health. In this study, a novel fluorometric sensor based on chlorophyll-rich carbon quantum dots (CQDs) for the detection of Hg2+ and As3+ ions was developed. The dual emitting (blue-green and red) CQDs were synthesized by a one-step solvothermal method using plumeria plant leaves as precursors. When Hg2+ ions were added in the presence of CQDs, the red emission (676 nm) of the CQDs was quenched (OFF), while in the presence of As3+ ions, the blue-green emission (485 nm) was enhanced (ON). The detection limits of 0.99 nM for Hg2+ and 12.15 nM for As3+ were validated for the proposed sensor. The biocompatibility, cytotoxicity, and bioimaging of the CQDs were investigated in the mouse fibroblast cell line NIH-3T3. The cellular uptake was also studied under the influence of Hg2+ and As3+ ions. Moreover, the novel chlorophyll-rich CQD-based fluorometric �ON-OFF� dual probe sensor was successfully applied to detect Hg2+ and As3+ in real water systems as well as in the mouse fibroblast cell line. � 2024 The Royal Society of Chemistry.enArticle10.1039/d3en00789h