AbstractThe authors describe a fluorescent probe for sensitive and selective determination of quercetin, an indicator for the freshness of drinks. The probe consists of silica ball encapsulated graphitic carbon nitride (g-C3N4) modified with a molecularly imprinted polymer (MIP). It was synthesized via reverse microemulsion. The resulting MIP@g-C3N4 nanocomposite was characterized by fluorescence spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Quercetin quenches the fluorescence of the MIP@g-C3N4 probe. The effect was used to quantify quercetin in grape juice, tea juice, black tea, and red wine by fluorometry (λexc = 350 nm, λem = 460 nm). Response is linear in the 10–1000 ng mL−1 quercetin concentration range. The detection limit is 2.5 ng mL−1, recoveries range between 90.7 and 94.1%, and relative standard deviations are between 2.1 and 5.5%. Graphical abstractSchematic of the synthesis of the MIP@g-C3N4 by a reverse microemulsion method. The probe was applied for the selective recognition and fluorometric determination of quercetin.

中文翻译：

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使用分子印迹聚合物修饰的石墨氮化碳纳米粒子荧光测定槲皮素

摘要作者描述了一种用于灵敏和选择性测定槲皮素的荧光探针，槲皮素是饮料新鲜度的指示剂。该探针由用分子印迹聚合物 (MIP) 改性的二氧化硅球封装的石墨氮化碳 (g-C3N4) 组成。它是通过反相微乳液合成的。所得 MIP@g-C3N4 纳米复合材料通过荧光光谱、透射电子显微镜、傅里叶变换红外光谱和 X 射线粉末衍射进行表征。槲皮素可淬灭 MIP@g-C3N4 探针的荧光。该效应用于通过荧光测定法（λexc = 350 nm，λem = 460 nm）量化葡萄汁、茶汁、红茶和红酒中的槲皮素。响应在 10–1000 ng mL-1 槲皮素浓度范围内呈线性。检测限为 2.5 ng mL-1，回收率范围在 90 之间。7% 到 94.1%，相对标准偏差在 2.1% 到 5.5% 之间。通过反微乳液法合成 MIP@g-C3N4 的图形摘要示意图。该探针用于槲皮素的选择性识别和荧光测定。