Chen Zhiqiang, Li Peipei, Cheng Xian, Yang Weijuan, Wu Yongning, Chen Qingai, Fu FengFu
Key Laboratory for Analytical Science of Food Safety and Biology of MOE, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
ACS Omega. 2019 Sep 6;4(12):15112-15119. doi: 10.1021/acsomega.9b01994. eCollection 2019 Sep 17.
Compared to inorganic mercury (Hg), methyl-mercury (CHHg) and ethyl-mercury (CHHg) (organic mercury) not only have a much stronger toxicity but also are more easily accumulated by marine organisms to produce bioamplification. Therefore, the simultaneously onsite detection of Hg and organic mercury is of great significance to ensure the safety of seafood, and it is also a hard challenge. We designed a T-rich aptamer, H, for specifically recognizing Hg and organic mercury and developed a multicolor aptasensor for simultaneous discrimination and detection of Hg and organic mercury with only bare-eye observation using H as a recognition probe and gold nanorods (AuNRs) as a signal. In the presence of Hg and Ag, Hg preferentially and specifically bind with H immobilized on AuNRs surface and induce the formation of a monolayer Ag/Hg amalgam on the AuNRs surface after reduction, resulting in a change in color from orange to faint purple and a corresponding shift in the absorption peak from 820 to 730 nm in the solution. However, in the presence of CHHg or CHHg and Ag, CHHg or CHHg preferentially bind with H immobilized on the AuNRs surface and induce the formation of a monolayer Ag on the AuNRs surface after reduction, which results in the change in color from orange to atrovirens and the corresponding shift in the absorption peak shift from 820 to 670 nm in the solution. Thus, the inorganic and organic mercury (total of CHHg and CHHg) can be specifically discriminated and detected by only bare-eye observation. The method can be used to simultaneously detect inorganic and organic mercury in seawater by the bare-eye observation with a visual detection limit of 2.0 ppm for Hg and 10.0 ppm for organic mercury. The success of this study is a useful enlightenment to develop an instrument-free method for an onsite detection of trace inorganic and organic mercury in environment by a bare-eye observation, although the sensitivity of the method is relatively low.
与无机汞（Hg）相比，甲基汞（CHHg）和乙基汞（CHHg）（有机汞）不仅毒性更强，而且更容易被海洋生物积累从而产生生物放大作用。因此，现场同时检测汞和有机汞对于确保海产品安全具有重要意义，同时也是一项艰巨的挑战。我们设计了一种富含胸腺嘧啶的适体H，用于特异性识别汞和有机汞，并开发了一种多色适体传感器，仅通过肉眼观察，以H作为识别探针，金纳米棒（AuNRs）作为信号，同时鉴别和检测汞和有机汞。在汞和银存在的情况下，汞优先与固定在金纳米棒表面的H特异性结合，并在还原后诱导在金纳米棒表面形成单层银汞合金，导致溶液颜色从橙色变为浅紫色，吸收峰从820 nm相应地位移至730 nm。然而，在甲基汞或乙基汞以及银存在的情况下，甲基汞或乙基汞优先与固定在金纳米棒表面的H结合，并在还原后诱导在金纳米棒表面形成单层银，这导致溶液颜色从橙色变为深绿色，吸收峰在溶液中从820 nm相应地位移至670 nm。因此，仅通过肉眼观察就可以特异性地鉴别和检测无机汞和有机汞（甲基汞和乙基汞的总和）。该方法可用于通过肉眼观察同时检测海水中的无机汞和有机汞，汞的目视检测限为2.0 ppm，有机汞为10.0 ppm。尽管该方法的灵敏度相对较低，但这项研究的成功为开发一种无需仪器的现场肉眼观察检测环境中痕量无机汞和有机汞的方法提供了有益的启示。
