Fluorescence-tunable copper nanoclusters and their application in hexavalent chromium sensing

• Published in: RSC advances 2019-03, Vol.9 (16), p.9228-9234
• Main Authors: Lin, Yu-Syuan, Chiu, Tai-Chia, Hu, Cho-Chun
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Chemistry; Chromium; Copper; Cysteamine; Fluorescent indicators; Hexavalent chromium; Ligands; Nanoclusters; Nanomaterials; Surface properties; Water purification
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra00916g

Generally, metal nanoclusters are synthesized using only a single ligand. Thus, the properties and applications of these nanomaterials are limited by the nature of the ligand used. In this study, we have developed a new synthetic strategy to prepare bi-ligand copper nanoclusters (Cu NCs). These bi-ligand Cu NCs are synthesized from copper ions, thiosalicylic acid, and cysteamine by a simple one-pot method, and they exhibit high quantum yields (>18.9%) and good photostability. Most interestingly, the fluorescence intensities and surface properties of the Cu NCs can be tailored by changing the ratio of the two ligands. Consequently, the bi-ligand Cu NCs show great promise as fluorescent probes. Accordingly, the Cu NCs were applied to the inner-filter-effect-based detection of hexavalent chromium in water. A wide linear range of 0.1-1000 μM and a low detection limit (signal-to-noise ratio = 3) of 0.03 μM was obtained. The recoveries for the real sample analysis were between 98.3 and 105.0% and the relative standard deviations were below 4.54%, demonstrating the repeatability and practical utility of this assay. Generally, metal nanoclusters are synthesized using only a single ligand.