Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
J Hazard Mater. 2016 Mar 5;304:66-72. doi: 10.1016/j.jhazmat.2015.10.036. Epub 2015 Oct 24.
In this work, a simple and sensitive Cr(VI) sensor is proposed based on fluorescent polyethyleneimine-stabilized Ag nanoclusters, which allows the determination over a wide concentration range of 0.1 nM-3.0 μM and with a detection limit as low as 0.04 nΜ and a good selectivity. The quenching mechanism was discussed in terms of the absorption and fluorescence spectra, suggesting that Cr(VI) is connected to Ag nanoclusters by hydrogen bond between the oxygen atom at the vertex of tetrahedron structure of Cr(VI) and the amino nitrogen of polyethyleneimine that surrounded Ag nanoclusters and electron transfer from Ag nanoclusters to highly electron-deficient Cr(VI) results in fluorescence quenching. Despite the failure to quench the fluorescence efficiently, Cr(III) can also be measured using the proposed Ag nanoclusters by being oxidized to Cr(VI) in alkaline solution (pH ∼ 9) containing H2O2. Therefore, our approach could be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution. In addition, Cr(VI) analysis in real water samples were satisfactory, indicating this method could be practically promising for chromium measurements.
在这项工作中，提出了一种基于荧光聚乙烯亚胺稳定的银纳米簇的简单灵敏的 Cr(VI) 传感器，它允许在 0.1 nM-3.0 μM 的宽浓度范围内进行测定，检测限低至 0.04 nΜ，具有良好的选择性。根据吸收和荧光光谱讨论了猝灭机制，表明 Cr(VI)通过四面体结构顶点的氧原子与包围 Ag 纳米簇的聚乙烯亚胺的氨基氮之间的氢键与 Ag 纳米簇相连，并且电子从 Ag 纳米簇转移到高电子缺的 Cr(VI)导致荧光猝灭。尽管未能有效地猝灭荧光，但 Cr(III)也可以通过在含有 H2O2 的碱性溶液（pH ∼ 9）中被氧化为 Cr(VI) 来使用所提出的 Ag 纳米簇进行测量。因此，我们的方法可用于检测水溶液中的 Cr(VI)、Cr(III)和总铬水平。此外，实际水样中的 Cr(VI)分析结果令人满意，表明该方法在铬测量方面具有实际应用前景。
