Copper nanoclusters @ nitrogen-doped carbon quantum dots-based ratiometric fluorescence probe for lead (II) ions detection in porphyra

A novel ratiometric fluorescence probe was proposed for detecting lead (II) ions (Pb 2+ ) in porphyra, the approach was based on copper nanoclusters and nitrogen-doped carbon quantum dots (CuNCs-CNQDs). In this probe, the CuNCs delivered the response signal, the fluorescence of which was enhanced by Pb 2+ due to the aggregation-induced emission enhancement (AIEE) between Pb 2+ and CuNCs. The CNQDs provided the self-calibration signal, whose fluorescence remained almost unchanged in coexistence with Pb 2+ . According to the change of fluorescence intensity ratio between the fluorophores, CuNCs–CNQDs nanohybrid was used as ratiometric probes for the sensitive detection of Pb 2+ in the range of 0.010–2.5 mg L −1 , with a detection limit of 0.0031 mg L −1 . Finally, the probe was successfully applied to detect Pb 2+ in porphyra with relative standard deviations (RSDs) lower than 5%. This study provides a straightforward, stable, and sensitive approach for detecting Pb 2+ in porphyra.