Table 1_A ratiometric fluorescent sensor for Al3+ and Cu2+ detection in food samples.doc

ObjectiveAluminum (Al) and copper (Cu), as two common elements, have specific applications in the modern food industry. However, excessive levels of Al3+ and Cu2+ 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. MethodsWe 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 Al3+ and Cu2+ in food samples. ResultsWhen the concentration of Al3+ in the reaction medium increases, the fluorescence intensity (FI) of G-AuNCs incrementally enhances; in contrast, when the concentration of Cu2+ increases, the FI of G-AuNCs is gradually quenched. Notably, the FI of N-GQDs remains unchanged throughout this process. When the concentrations of Al3+ and Cu2+ ions are within the ranges of 0.5–500 μM and 1–200 μM, respectively, the FI ratio (I528/I412)/(I528/I412)0 shows a strong linear correlation with the ion concentrations, with corresponding limits of detection (LOD) of 0.66 μM and 0.44 μM. ConclusionThe fluorescent sensor features simple synthesis, rapid detection, and high sensitivity, making it well-suited for the rapid detection of Al3+ and Cu2+ in foods such as fried dough twists and shellfish.一、研究目标 铝（Aluminum, Al）与铜（Copper, Cu）作为两种常见元素，在现代食品工业中具备特定应用价值。然而，过量的三价铝离子（Al³+）与二价铜离子（Cu²+）会对生态系统及人类健康构成严重威胁。因此，快速、灵敏且便携的检测技术对于实现这类危险物质的源头管控不可或缺。 二、实验方法 本研究通过简便的水热法合成了谷胱甘肽稳定金纳米团簇（GSH-stabilized gold nanoclusters, G-AuNCs）与氮掺杂石墨烯量子点（Nitrogen-doped graphene quantum dots, N-GQDs），并借助静电相互作用构建了GQDs@AuNCs比率型荧光传感器，用于食品样品中Al³+与Cu²+的快速检测。 三、实验结果 当反应介质中Al³+浓度升高时，G-AuNCs的荧光强度（Fluorescence Intensity, FI）会逐步增强；与之相反，当Cu²+浓度升高时，G-AuNCs的FI则会逐渐被猝灭。值得注意的是，整个实验过程中N-GQDs的FI始终保持稳定。当Al³+与Cu²+的浓度分别处于0.5~500 μM与1~200 μM范围内时，荧光强度比(I528/I412)/(I528/I412)0与离子浓度呈现极强的线性相关关系，对应的检测限（Limit of Detection, LOD）分别为0.66 μM与0.44 μM。 四、研究结论 该荧光传感器具备合成简便、检测快速、灵敏度高的优势，非常适用于油条、贝类等食品中Al³+与Cu²+的快速检测。