Ning Sui,Fengya Liu,Ke Wang,Fengxia Xie,Lina Wang,Juanjuan Tang,Manhong Liu,William W. Yu
In this work, gold nanoparticles were synthesized, the introduction of Hg 2+ led to the formation of Au-Hg amalgam , which was found to possess an enhanced peroxidase-mimicking activity towards H 2 O 2 -mediated oxidation of 3, 3′, 5, 5′-Tetramethylbenzidine (colorless) to produce a blue product. This color reaction was exploited as a sensitive and selective method for colorimetric detection of Hg 2+ and H 2 O 2 , the linear ranges were 0.1–5 nM and 0.5–100 μ M, respectively. Furthermore, a test strip was successfully designed, it exhibited high sensitive, rapid and low cost for Hg 2+ and H 2 O 2 detection. More importantly, the colorimetric method could be successfully applied to real sample application in solution and in a test strip.
It is imperative to develop a rapid detection method for Hg2+ due to its harm to human health and the ecological environment. In this research, CuO/Au@Cu3(BTC)2 was synthesized through reducing HAuCl4 by CuxO@Cu3(BTC)2, which was obtained by reducing Cu3(BTC)2 with hydrazine hydrate. The oxidase-mimic activity of CuO/Au@Cu3(BTC)2 can be enhanced by Hg2+ through forming a Au–Hg alloy. Therefore, a colorimetric method was designed for Hg2+ detection with a linear relationship in the 0.05–25 μM range and a limit of detection of 9.7 nM. This strategy exhibited a strong selectivity to Hg2+ and was applied in a real water sample with reliable recoveries. This work provides a possibility for the rapid detection of Hg2+.
Keyan Chen,Shiqi Fu,Chenyu Jin,Fan Guo,Yu He,Qi Ren,Xuesheng Wang
Smartphone-assisted fluorescence and colorimetric methods for the on-site detection of Hg2+and Cl−were established based on the oxidase-like activity of the Au–Hg alloy on the surface of Au/Cu/Ti3C2NSs. The Au nanoparticles (NPs) were constructed via in-situ growth on the surface of Cu/Ti3C2NSs and characterized by different characterization techniques. After the addition of Hg2+, the formation of Hg–Au alloys could promote the oxidization of o-phenylenediamine (OPD) to generate a new fluorescence emission peak of 2,3-diaminopenazine (ADP) at 570 nm. Therefore, a turn-on fluorescence method for the detection of Hg2+was established. As the addition of Cl−can influence the fluorescence of ADP, the fluorescence intensity was constantly quenched to achieve the continuous quantitative detection of Cl−. Therefore, a turn-off fluorescence method for the detection of Cl−was established. This method had good linear ranges for the detection of Hg2+and Cl−in 8.0–200.0 nM and 5.0–350.0 µM, with a detection limit of 0.8 nM and 27 nM, respectively. Depending on the color change with the detection of Hg2+and Cl−, a convenient on-site colorimetric method for an analysis of Hg2+and Cl−was achieved by using digital images combined with smartphones (color recognizers). The digital picture sensor could analyze RGB values in concentrations of Hg2+or Cl−via a smartphone app. In summary, the proposed Au/Cu/Ti3C2NSs-based method provided a novel and more comprehensive application for environmental monitoring.Keywords:Au/Cu/Ti3C2NS;Au–Hg alloy;oxidase-like activity;smartphone;colorimetric detection
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