Dual-emission ratiometric fluorescent detection of dinotefuran based on sulfur-doped carbon quantum dots and copper nanocluster hybrid

Developing dinotefuran (DNF) sensing probe is crucial for the monitoring of DNF residues. A dual-emission ratiometric fluorescent probe of sulfur-doped carbon quantum dots (S-CQDs) and copper nanoclusters (CuNCs) hybrid (S-CQDs/CuNCs) were developed for sensitive and selective detection of DNF. The fluorescent signals of CuNCs were quenched in the presence of DNF, while the fluorescent signals of S-CQDs enhanced after the addition of DNF. The ratiometric fluorescent performance of as-developed probe was mainly based on the inner filter effect (IFE) between S-CQDs and CuNCs. Interestingly, the aggregation of CuNCs occurred after the addition of DNF, reducing the IFE effect between S-CQDs and CuNCs, leading to the fluorescent intensity of S-CQDs recovered and CuNCs fluorescence decayed. The ratiometric fluorescent performance of S-CQDs/CuNCs illustrated a good sensitivity and selectivity ranging from 10 μM and 500 μM, with a low detection limit of 7.04 μM. Importantly, real samples investigations implied the good application potential of S-CQDs/CuNCs in DNF monitoring.