Wang Na, Wang Liangchen, Yang Hong, Xiong Tingting, Xiao Shangping, Zhao Jiawen, Du Weiping
School of Chemistry & Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, China.
Int J Anal Chem. 2019 Feb 3;2019:1756014. doi: 10.1155/2019/1756014. eCollection 2019.
"Turn-off" fluorescent sensors for Cr(VI) have been fabricated based on organic polymer-capped gold nanoparticles. The fluorescence intensity, as well as the response behavior of the sensors, is dependent on the pH values of buffer solution and dilution amounts of the sensors. When diluted 50 times with pH 2.0 buffer solution, the sensors show good linear responses toward Cr(VI) at concentrations between 2.8-5.9 M and 5.9-29 M. The calculated detection limit is 0.63 M (S/N=3). The interference study and real sample assays exhibit satisfying selectivity and reliability results. Furthermore, the quenched intensity of fluorescence could be recovered by Fe(II) ion, which provides a potential method to detect Fe(II) ions. The quenching and recovering mechanisms have also been investigated. It is suggested that the quenching mechanism is based on the combined effects of internal electron transfer and the inner filter effect. Finally, the recovering mechanism is based on the redox reactions between the Cr(VI) and Fe(II) ions.
基于有机聚合物包覆的金纳米粒子制备了用于检测六价铬（Cr(VI)）的“关断型”荧光传感器。传感器的荧光强度及其响应行为取决于缓冲溶液的pH值和传感器的稀释倍数。当用pH 2.0的缓冲溶液稀释50倍时，传感器在2.8 - 5.9 μM和5.9 - 29 μM浓度范围内对Cr(VI)呈现良好的线性响应。计算得到的检测限为0.63 μM（S/N = 3）。干扰研究和实际样品分析显示出令人满意的选择性和可靠性结果。此外，荧光猝灭强度可被Fe(II)离子恢复，这为检测Fe(II)离子提供了一种潜在方法。还研究了猝灭和恢复机制。结果表明，猝灭机制基于内电子转移和内滤光效应的综合作用。最后，恢复机制基于Cr(VI)与Fe(II)离子之间的氧化还原反应。
