Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
ACS Appl Mater Interfaces. 2014 Dec 10;6(23):21461-7. doi: 10.1021/am5064603. Epub 2014 Nov 11.
Highly green emissive gold nanoclusters (Au NCs) are synthesized using glutathione as a stabilizing agent and mercaptopropionic acid as a ligand, and the intensity of fluorescence is specifically sensitive to lead ions. We then fabricated a ratiometric fluorescence nanohybrid by covalently linking the green Au NCs to the surface of silica nanoparticles embedded with red quantum dots (QDs) for on-site visual determination of lead ions. The green fluorescence can be selectively quenched by lead ions, whereas the red fluorescence is inert to lead ions as internal reference. The different response of the two emissions results in a continuous fluorescence color change from green to yellow that can be clearly observed by the naked eyes. The nanohybrid sensor exhibits high sensitivity to lead ions with a detection limit of 3.5 nM and has been demonstrated for determination of lead ions in real water samples including tap water, mineral water, groundwater, and seawater. For practical application, we dope the Au NCs in poly(vinyl alcohol) (PVA) film and fabricate fluorescence test strips to directly detect lead ions in water. The PVA-film method has a visual detection limit of 0.1 μM, showing its promising application for on-site identification of lead ions without the need for elaborate equipment.
高绿色发光金纳米团簇（Au NCs）是使用谷胱甘肽作为稳定剂和巯基丙酸作为配体合成的，其荧光强度对铅离子具有特异性敏感性。然后，我们通过将绿色 Au NCs 共价连接到嵌入红色量子点（QDs）的硅纳米粒子表面，制备了比率荧光纳米杂化体，用于现场可视化测定铅离子。绿色荧光可以被铅离子选择性猝灭，而红色荧光作为内标对铅离子不敏感。两种发射的不同响应导致从绿色到黄色的连续荧光颜色变化，可以用肉眼清楚地观察到。纳米杂化体传感器对铅离子具有高灵敏度，检测限为 3.5 nM，并已用于测定包括自来水、矿泉水、地下水和海水在内的实际水样中的铅离子。为了实际应用，我们将 Au NCs 掺杂到聚乙烯醇（PVA）薄膜中，并制备荧光测试条，以直接检测水中的铅离子。PVA 膜法的目视检测限为 0.1 μM，表明其有望用于无需复杂设备的现场识别铅离子。
