AbstractA method is described for the colorimetric determination of mercury(II). In the absence of Hg(II), aminopropyltriethoxysilane (APTES) which is positively charged at pH 7 is electrostatically absorbed on the surface of gold nanoparticles (AuNPs). This neutralizes the negative charges of the AuNPs and leads to NP aggregation and a color change from red to blue-purple. However, in the presence of Hg(II), reduced Hg (formed through the reaction between Hg(II) and citrate on the AuNP surface) will replace the APTES on the AuNPs. Hence, the formation of aggregates is suppressed and the color of the solution does not change. The assay is performed by measuring the ratio of absorbances at 650 and 520 nm and can detect Hg(II) at nanomolar levels with a 10 nM limit of detection. The specific affinity between mercury and gold warrants the excellent selectivity for Hg(II) over other environmentally relevant metal ions. Graphical AbstractSchematic of the method for determination of Hg2+ based on the gold amalgam-induced deaggregation of gold nanoparticles in the presence of APTES with the LOD of 10.1 nM.

中文翻译：

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通过金汞合金诱导的金纳米粒子解聚比色测定 Hg(II)

摘要 描述了一种比色法测定汞 (II) 的方法。在不存在 Hg(II) 的情况下，在 pH 值为 7 时带正电荷的氨基丙基三乙氧基硅烷 (APTES) 被静电吸附在金纳米粒子 (AuNPs) 的表面上。这会中和 AuNP 的负电荷并导致 NP 聚集和颜色从红色变为蓝紫色。然而，在 Hg(II) 存在的情况下，还原的 Hg（通过 Hg(II) 与 AuNP 表面柠檬酸盐之间的反应形成）将取代 AuNP 上的 APTES。因此，聚集体的形成被抑制并且溶液的颜色不会改变。该测定通过测量 650 和 520 nm 处的吸光度比进行，可以检测纳摩尔级的 Hg(II)，检测限为 10 nM。汞和金之间的特殊亲和力保证了 Hg(II) 优于其他环境相关金属离子的选择性。图形摘要基于在 APTES 存在下金纳米粒子的金汞齐诱导解聚的 Hg2+ 测定方法示意图，LOD 为 10.1 nM。