Abstract
OBJECTIVE: Aluminum (Al) and copper (Cu), as two common elements, have specific applications in the modern food industry. However, excessive levels of Al(3+) and Cu(2+) pose a major risk to ecosystems and human health. Thus, fast, sensitive, and portable detection technologies are indispensable for achieving source control of such hazardous substances. METHODS: We synthesized GSH-stabilized gold nanoclusters (G-AuNCs) and Nitrogen-doped graphene quantum dots (N-GQDs) via a straightforward hydrothermal method, and constructed GQDs@AuNCs ratiometric fluorescent sensors through electrostatic interactions for the rapid detection of Al(3+) and Cu(2+) in food samples. RESULTS: When the concentration of Al(3+) in the reaction medium increases, the fluorescence intensity (FI) of G-AuNCs incrementally enhances; in contrast, when the concentration of Cu(2+) increases, the FI of G-AuNCs is gradually quenched. Notably, the FI of N-GQDs remains unchanged throughout this process. When the concentrations of Al(3+) and Cu(2+) ions are within the ranges of 0.5-500 μM and 1-200 μM, respectively, the FI ratio (I(528)/I(412))/(I(528)/I(412))(0) shows a strong linear correlation with the ion concentrations, with corresponding limits of detection (LOD) of 0.66 μM and 0.44 μM. CONCLUSION: The fluorescent sensor features simple synthesis, rapid detection, and high sensitivity, making it well-suited for the rapid detection of Al(3+) and Cu(2+) in foods such as fried dough twists and shellfish.