Sudan III, a commonly used dye in cosmetics, poses health risks due to its potential carcinogenicity and allergenic properties, necessitating rigorous monitoring of its illegal presence in consumer goods. In this study, a novel fluorometric assay employing Nitrogen-doped Carbon Quantum Dots coated with Molecularly Imprinted Polymers (NCQDs/SiO2@MIP) is presented to accurately and sensitively detect Sudan III. Unlike other majority analytes, Sudan III shows fluorescence enhancement upon binding with our NCQDs-MIPs. Under optimal conditions—pH 7.0, histidine buffer, 15 min incubation, and 500 mg/L NCQDs/SiO2@MIP—the method achieves a low 1.4 nM (0.49 ppb) detection limit and a broad linear range (5–800 nM). With precision (RSD < 5 %) and selectivity surpassing Sudan dyes and common cosmetic ingredients, the method’s reliability is evident. Cross-validation against LC-MS/MS confirms the accuracy of Sudan III quantification in real cosmetic samples. This NCQDs/SiO2@MIP fluorometric sensor holds promise for rapid on-site detection of Sudan III and other contaminants in cosmetics, offering superior sensitivity, selectivity, and minimal sample preparation requirements.
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