A fast, simple, green and low-cost synthesis method in aqueous solution was successfully established for the preparation of l-tyrosine protected Cu nanoclusters (Cu NCs). Subsequently, the as-prepared Cu NCs was characterized by UV–vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It exhibited good water solubility, excellent photostability and high stability toward high concentration of sodium chloride. The Cu NCs revealed maximum excitation and emission peaks at 430 and 477 nm, respectively. Importantly, the Cu NCs showed a rapid response, a liner relation over the pH ranges from 5.02 to 11.92 and could be repeated for five consecutive cycles without fluorescence decay. Further, the as-prepared Cu NCs was applied for the determination of pH value in water samples. Simultaneously, all above features showed that l-tyrosine protected Cu NCs had great potential for sensing of pH in biological field.

中文翻译：

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l-酪氨酸保护的铜纳米簇，用于可逆pH传感器

成功地建立了一种快速，简单，绿色，低成本的水溶液合成方法来制备l-酪氨酸保护的Cu纳米簇（Cu NCs）。随后，通过紫外可见吸收光谱，荧光光谱，透射电子显微镜（TEM）和X射线光电子能谱（XPS）对制备的Cu NCs进行表征。它具有良好的水溶性，优异的光稳定性和对高浓度氯化钠的高稳定性。Cu NCs分别在430和477 nm处显示最大激发和发射峰。重要的是，Cu NCs显示出快速响应，在pH范围为5.02至11.92范围内具有线性关系，可以连续五个循环重复，而不会发生荧光衰减。此外，将所制备的Cu NCs用于测定水样中的pH值。同时，所有的上述特点表明，升酪氨酸保护的Cu NCs在生物领域具有巨大的pH感测潜力。