Facile Synthesis of S-doped Carbon Quantum Dots and Their Application in the Detection of Sudan I in Saffron

This study employed citric acid as a carbon source and thiourea as a sulphur source to conduct a straightforward one-step microwave synthesis of sulphur-doped carbon quantum dots (SCQDs). For the characterization of as-synthesized SCQDs, several methods such as fluorescence spectroscopy, X-Ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), and zeta potential analyzer were utilized. XRD and XPS spectroscopy are used to examine the chemical composition and morphological aspects. These QDs have a limited size distribution spanning up to 5.89 nm, with a maximum distribution at 7 nm, according to zeta size analyser examinations. At an excitation wavelength of 340 nm, the highest fluorescence intensity (FL intensity) of SCQDs was attained. With a detection limit of 0.77 M, the synthesized SCQDs were employed as an efficient fluorescent probe for the detection of Sudan I in saffron samples.