Fluorine-doped carbon quantum dots for sunset yellow analysis in complex food matrices

Sunset yellow (SY) is a widely used artificial food coloring that can pose health risks when consumed in excess. In this study, a fluorescent sensor for the quantitative analysis of SY content in complex foods was reported. Using ammonium fluoride and sorbic acid as precursors, fluorine-doped carbon quantum dots (F-CDs) were synthesized via solvothermal method. The prepared F-CDs were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results revealed that F-CDs had a uniform morphology and fluorine-rich structure, with an average particle size of 2.15 nm. In addition, we found that F-CDs exhibited excellent selectivity for SY, mainly due to the fluorescence quenching effect of SY on F-CDs. Therefore, a fluorescent sensor based on F-CDs was constructed with a linear detection range of 0.010–75 μM ( R 2  = 0.997) and a detection limit of 30 nM. The sensor's practical applicability was demonstrated by analyzing of SY in hard candy, tangerine peel sugar, peach jelly, beer, and bread, with recoveries of 92.1%–115% and RSDs of 1.0–4.8%. What's more, the fluorescence detection results were closely related to the HPLC-DAD validation results (relative deviation ≤0.17), highlighting the accuracy of the method. F-CD-based fluorescence detection platforms offer the advantages of simplicity, sensitivity, and reliability, providing a promising tool for routine SY monitoring in food safety applications.