Dual-emission carbon dots as ratiometric fluorescence probe for rutin detection

Herein, a novel type of nitrogen and sulfur co-doped dual-emission carbon dots (N, S-CDs) was successfully synthesized through a one-step hydrothermal method, utilizing o-diaminobenzene and sulfosalicylic acid as precursors. The prepared N, S-CDs exhibited two distinct emission peaks located at 345 nm and 435 nm when excited at 305 nm. Notably, rutin (RT) can selectively quench the emission of N, S-CDs at 345 nm via fluorescence resonance energy transfer (FRET) mechanism, while the fluorescence intensity at 435 nm is essentially stable. As a result, the fluorescence intensity ratio of the dual emission wavelengths at 345 nm and 435 nm gradually decreased with the increase of RT concentration. There was a good linear relationship between the change in fluorescence intensity ratio ( F 0 F ) /F 0 and the concentration of RT in the range of 0.5–60 μM, and the limit of detection was 0.14 μM. Furthermore, the ratiometric fluorescent sensor based on N, S-CDs proved to be highly effective for detecting RT in real samples such as human blood serum, urine, and RT tablet, achieving satisfactory recovery rates and demonstrating broad potential for future applications.