芦丁是一类重要的黄酮类化合物, 具有抗肿瘤、 抗糖尿病、 抗氧化等多种生理功能, 因此开发简便、 灵敏的芦丁检测新方法具有十分重要意义。 基于谷胱甘肽稳定的荧光铜纳米簇(GSH-CuNCs), 构建了一种简单、 高灵敏、 高选择性的荧光传感新方法用于芦丁的检测。 以谷胱甘肽(GSH)为稳定剂, 抗坏血酸(AA)为还原剂, 制备了具有优良发光性能的谷胱甘肽稳定的铜纳米簇(GSH-CuNCs)。 采用紫外吸收光谱、 荧光激发光谱和发射光谱对GSH-CuNCs的光学性能进行了研究。 GSH-CuNCs在365 nm激发波长下, 在420 nm处具有强的荧光发射。 GSH-CuNCs在293 nm(紫外光区)处有明显的吸收峰, 但在400 nm(可见光区)以上没有吸收。 结果表明, GSH-CuNCs具有类似分子的性质, 并且没有较大的铜纳米颗粒存在, 说明所制备GSH-CuNCs的纯度较高。 在4 ℃条件下贮存3个月后, GSH-CuNCs在420 nm处的荧光强度仍保持在96%以上。 当芦丁(Rutin)存在时, 铜纳米簇的荧光信号被显著猝灭。 这是由于芦丁的吸收光谱与GSH-CuNCs的荧光激发光谱有较大的重叠, 引发内滤效应所致。 对测定芦丁的pH值和反应时间进行了优化, 发现当pH值为7.5, 反应时间为10 min时, 荧光猝灭效果较好。 在优化的实验条件下, 测定了存在不同浓度芦丁时GSH-CuNCs的荧光发射光谱。 结果表明, 该传感方法对芦丁具有良好的荧光响应, 检测线性范围为1.00~200 nmol·L^-1, 检出限为0.300 nmol·L^-1。 在传感系统中引入相同浓度的其他干扰物质时, 只有芦丁对GSH-CuNCs的荧光信号有明显的猝灭作用, 表明该方法对于芦丁的检测具有良好的选择性。 该方法已经用于荞麦茶样品中芦丁含量的测定。 该方法无需修饰, 简便易行, 样品消耗少, 具有较高的灵敏度。

Rutin, an important kind of flavonoid, has some physiological functions, including antitumor activity, anti-diabetic, anti-oxidation, etc. Thus, it is important to develop a novel method for the simple and sensitive determination of rutin. A simple, highly sensitive and highly selective fluorescence sensor has been established to detect rutin based on glutathione-stabilized copper nanoclusters (GSH-CuNCs). GSH-CuNCs with excellent luminescent properties were prepared using glutathione (GSH) as a stabilizer and ascorbic acid (AA) as a reductant. Ultraviolet absorption spectra, fluorescence excitation and emission spectra studied the optical properties of GSH-CuNCs. The results showed that the GSH-CuNCs have strong fluorescence emission at 420 nm with an excitation wavelength of 365 nm. The absorption spectra showed that the GSH-CuNCs have an obvious absorption peak at 293 nm (UV region), but no absorption was observed above 400 nm (visible region). It was indicated that the GSH-CuNCs had molecular-like properties and did not have larger copper nanoparticles, suggesting the high purity of GSH-CuNCs. Moreover, the fluorescence intensity (at 420 nm) of GSH-CuNCs remained at about 96% after being stored at 4 ℃ for 3 months. When rutin was present, the fluorescence intensity of GSH-CuNCs was significantly quenched. It was ascribed to the absorption spectra of Rutin overlapped largely with the fluorescence excitation spectra of GSH-CuNCs, which led to the inter-filter effect (IFE). The effect of pH and reaction time for the detection of Rutin was optimized. It was found that the quenching effect was the best when pH was 7.5 and the reaction time was 10 minutes. Under optimum experimental conditions, the fluorescence emission spectrum of GSH-CuNCs was recorded with different concentrations of Rutin. The results confirmed that the sensor had a good fluorescence response to Rutin, with a linear range of 1.00~200 nmol·L^-1 and a limit of detection of 0.300 nmol·L^-1. Different interfering substances with the same concentration were introduced into the sensing system. It was observed that the fluorescence intensity of GSH-CuNCs could be quenched only in the presence of Rutin, which implied that this method has a good selectivity for determining Rutin. The method has been applied to detect rutin content in buckwheat tea samples. This assay was no modification, simple and convenient, and with less sample consumption has good sensitivity.