A new specific and sensitive colorimetric sensor based on anti-aggregation of unmodified gold nanoparticles (AuNPs) for mercury ion detection was studied by forming Au-Hg alloys deposited onto the surface of AuNPs. In the protocol, hexadecyl trimethyl ammonium bromide (CTAB) could cause the aggregation of AuNPs and induced the color change from red to blue due to the strong electrostatic attraction between CTAB and citrate ion capped gold nanoparticles. In the presence of Hg²⁺, citrate ion capped AuNPs reduced Hg²⁺ to Hg and then formed Hg-Au alloys, which could inhibit the aggregation of AuNPs caused by CTAB to some extent. Based on these findings, Hg²⁺ was detected by a blue-to-red color change of AuNPs solution containing CTAB. Also, the limit of detection (LOD) was 11.9 nM by UV–vis spectroscopy, which was lower than the guideline concentration of Hg²⁺ (30 nM) in drinking water set by the World Health Organization (WHO). And the results showed the absorbance ratios A₆₅₀/A₅₂₀ had a good linear correlation with the Hg²⁺ concentration from 0 to 680 nM, which could be used for the quantitative detection of Hg²⁺. This method was successfully used to detect Hg²⁺ in tap water sample.

通过形成沉积在AuNPs表面的Au-Hg合金，研究了一种基于未修饰的金纳米颗粒（AuNPs）的抗聚集性的新型特异性灵敏比色传感器，用于汞离子检测。在该协议中，十六烷基三甲基溴化铵（CTAB）可能会引起AuNP的聚集，并由于CTAB和柠檬酸盐离子封端的金纳米粒子之间的强静电吸引作用，导致颜色从红色变为蓝色。在存在Hg ²⁺的情况下，柠檬酸根离子封端的AuNPs将Hg ²⁺还原为Hg，然后形成Hg-Au合金，在一定程度上可以抑制CTAB引起的AuNPs聚集。基于这些发现，Hg ²⁺含有CTAB的AuNPs溶液从蓝到红的颜色变化可以检测到这种现象。另外，紫外可见光谱法的检出限（LOD）为11.9 nM，低于世界卫生组织（WHO）设定的饮用水中Hg ²⁺的指导浓度（30 nM）。结果表明，吸光度比值A ₆₅₀ / A ₅₂₀与Hg ²⁺浓度在0至680 nM之间具有良好的线性相关性，可用于Hg ²⁺的定量检测。该方法已成功用于自来水样品中Hg ^2+的检测。