Dual-emission carbon dots for ratiometric fluorescence sensing of thiabendazole in fruits

Quantitative determination of pesticides in fruits and vegetables is essential for human healths. Herein, a new dual-emission carbon dots with high fluorescence stability at a pH range of 4-10 and a temperature range of 0-60 degrees C was synthesized. And a novel ratiometric fluorescence probe was proposed to detect thiabendazole (TBZ) residue with a wide linear range (0-1000 mu M) and low detection limit (0.15 mu M). The emission at 512 nm exhibited a special "turn-off" fluorescence sensing of TBZ due to internal filter effect, while that at 361 nm barely changed and worked as reference. Furthermore, the ratiometric fluorescence strategy was successfully applied for determining TBZ in fruits with good recoveries (96.73%-111.17 %, 93.29%-120.78 % and 96.28%-100.57 %, respectively). Notably, the constructed ratiometric fluorescence probe had comparable accuracy to HPLC in detecting unknown concentrations of TBZ in pear juice, demonstrating dual-emission carbon dots possess wide and promising applicability for fluorescence sensing pesticides in the future.