Preparation of carbon quantum dots from cigarette filters and its application for fluorescence detection of Sudan I.

Carbon quantum dots (CQDs) with quantum yield of 14% were successfully synthesized via a simple, low-cost, and green hydrothermal treatment using cigarette filters as carbon source for the first time. The obtained CQDs showed a strong emission at the wavelength of 465 nm, with an optimum excitation of 365 nm.Sudan I with maximum absorption wavelength at 477 nm could selectively quench the fluorescence of CQDs. Based on this principle, a fluorescence probe was developed for Sudan I determination. Furthermore, the quenching mechanism of the CQDs was elucidated. A linear relationship was found in the range of 2.40-104.0 µmol/L Sudan I with the detection limit (3σ/k) of 0.95 µmol/L. Satisfactory results were achieved when the method was submitted to the determination of Sudan I in food samples.