Fluorescent probe based nitrogen doped carbon quantum dots with solid-state fluorescence for the detection of Hg2+ and Fe3+ in aqueous solution

[Display omitted] •Nitrogen doped carbon quantum dots (NCQDs) were prepared from tartaric acid and L-arginine.•The NCQDs appear blue fluorescence in solution and yellow-green fluorescence in solid state.•Selective and sensitive detection of Hg2+ and Fe3+ were achieved based on NCQDs.•The NCQDs were applied in the detection of Hg2+ and Fe3+ in real water samples. Novel nitrogen doped carbon quantum dots (NCQDs) have been synthesized through a solvothermal method with tartaric acid and L-arginine as the precursors. The NCQDs appear blue fluorescence in aqueous solution and yellow-green fluorescence in solid state and the solution of NCQDs exhibits the quantum yield of 8.3%, good photostability, resistance to acid or base. It was found that the NCQDs have potential as ink in information encryption and a fluorescence probe in the detection of Hg2+ and Fe3+. Under optimal conditions, response is linear (R2 ≥ 0.99) in the range of 0–5.0 μM (Hg2+) and 0–70 μM (Fe3+), the limits of detection are 0.017 μM (Hg2+) and 0.50 μM (Fe3+) (S/N = 3), respectively. The established method was successfully applied to the determination of Hg2+ and Fe3+ in tap and river water samples. The results indicate the NCQDs-based probe has potential in real sample analysis.