Synthesis of dual-emission carbon quantum dots for ratiometric fluorescence detection of tartrazine

Tartrazine is widely utilized in food and pharmaceutical industries. Long-term excessive intake of tartrazine may cause severe health issues, which underscores the great significance of rapid and accurate detection of tartrazine. In the study, dual-emission CQDs (DE-CQDs) were synthesized via one-pot hydrothermal method using sodium citrate, Rose Bengal, and diethylenetriamine at 180 °C. The as-prepared DE-CQDs exhibited dual emission peaks centered at 435 nm and 520 nm under excitation at 330 nm, along with excellent stability in high concentration of NaCl solutions and good photostability. Notably, the introduction of tartrazine induced significant fluorescence quenching at 435 nm, while causing a slow decrease in fluorescence intensity at 520 nm. This distinct response enabled the development of a highly sensitive ratiometric fluorescence sensor for tartrazine detection. The sensor achieved a wide linear detection range of 0–200 μM with an impressive limit of detection of 0.10 μM. Furthermore, the practical application of this sensing platform was successfully validated through real sample analysis, yielding satisfactory recoveries.