Detection of Ag+ ions via an anti-aggregation mechanism using unmodified gold nanoparticles in the presence of thiamazole
2021
Mao, Lihui | Wang, Qianqian | Luo, Yuhao | Gao, Yongping
The present study proposed a novel and highly selective and sensitive method for Ag⁺ ion detection based on gold nanoparticles (AuNPs) anti-aggregation. Thiamazole can induce AuNPs aggregation due to electrostatic interactions, which result in color transitions in the AuNPs solution from red to blue. However, the presence of Ag⁺ ions results in the preferential combination of the pyridinic nitrogen of thiamazole with the Ag⁺ ions. In addition, the Ag⁺ ions oxidize the sulfhydryl groups(-SH), which inhibit AuNPs aggregation and prompt a color change from blue to red. As a result, the present study established a method for Ag⁺ ion determination by AuNPs-thiamazole colorimetric probe based on the aforementioned anti-aggregation mechanism. The probe dynamic range was easily tuned via adjustments of the thiamazole amount. The relationship between the Ag⁺ concentration and AuNPs aggregation was monitored by ultraviolet–visible light (UV–Vis) spectroscopy at a dynamic range of 0.1 nM–9 μM and at a detection limit of 0.042 nM. The river water and tap water recovery analysis validated the successful operation of this colorimetric sensor in environmental monitoring.
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