Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Sci Rep. 2023 Feb 1;13(1):1844. doi: 10.1038/s41598-023-27406-9.
Herein, a sensitive colorimetric detection strategy is proposed for Ag detection based on the use of environmentally friendly synthesis of gold nanoparticles (AuNPs), at room temperature, using (tannic acid, TA), as the reductant and pullulan (PUL) as stabilizing agent. The colloidal solution (TA/PUL-AuNPs), at the optimal synthesis conditions, showed maximum absorbance at 529 nm with a berry red color. TEM and FESEM validated that the particles are spherical and monodispersed, while other characterization results elucidated the role of pullulan in the nano-synthesis. Ag addition to the probe (TA/PUL-AuNPs), pH 11, resulted in naked-eye color changes, owing to Au@Ag core shell nanostructure formation. Further, the added Ag is reduced to AgNPs, on the surface of the TA/PUL-AuNPs probe. A hypsochromic shift in the absorption maximum, from 529 to 409 nm was observed, while (A-A)@409 nm exhibited linearity with Ag concentrations, from 0.100 to 150 µM. The estimated limit of detection was 30.8 nM, which is far lower than the acceptable limit of 0.930 µM from the regulatory agency. The TA/PUL-AuNPs probe was further tested for Ag detection in lake water samples, and it displayed satisfactory detection performances for real sample applications.
本文提出了一种基于金纳米粒子（AuNPs）的环保室温合成法，用于 Ag 检测的灵敏比色检测策略，所用还原剂为（没食子酸，TA），稳定剂为普鲁兰（PUL）。在最佳合成条件下，胶体溶液（TA/PUL-AuNPs）在 529nm 处具有最大吸光度，呈浆果红色。TEM 和 FESEM 验证了粒子是球形且单分散的，而其他表征结果阐明了普鲁兰在纳米合成中的作用。向探针（TA/PUL-AuNPs）中加入 Ag，在 pH 11 条件下，由于形成 Au@Ag 核壳纳米结构，导致出现肉眼可见的颜色变化。此外，加入的 Ag 在 TA/PUL-AuNPs 探针表面被还原为 AgNPs。观察到最大吸收峰从 529nm 到 409nm 的蓝移，而（A-A）@409nm 与 Ag 浓度呈线性关系，范围为 0.100 至 150µM。估计的检测限为 30.8nM，远低于监管机构规定的 0.930µM 可接受限值。该 TA/PUL-AuNPs 探针进一步用于湖水样品中的 Ag 检测，对实际样品应用显示出令人满意的检测性能。
