Chen Ling, Li Rui, Yang Ping
School of Materials Science and Engineering, University of Jinan Jinan 250022 China
RSC Adv. 2019 Jun 5;9(31):17783-17790. doi: 10.1039/c9ra02168j. eCollection 2019 Jun 4.
We report a sensitive and selective localized surface plasmon resonance (LSPR) nanoprobe for the detection of mercuric ions (Hg) using gold/silver core-shell nanorods as an optical nanosubstrate. Sulfide can quickly react with silver atoms to generate AgS at room temperature in the presence of oxygen. The transformation from Ag shell to AgS on the nanorod surface results in its LSPR absorption band shifting to a longer wavelength, which is attributed to their different refractive indices. Interestingly, the morphology also changed from a rod-like to dumbbell shape. However, in the presence of Hg, this morphology transformation is inhibited because the sulfide reacts with free Hg prior to the Ag atoms. The amount of AgS reduced with the increasing concentration of Hg, and the absorption band shift was also decreased. According to this "rod-like to dumbbell or not" shape change, a sensitive and selective LSPR nanoprobe was established, assisted by UV-Vis absorption spectroscopy. The detection limit of this probe for Hg was as low as 13 nM. The efficiency of this probe in complex samples was evaluated by the detection of Hg in spiked water samples.
我们报道了一种灵敏且具选择性的局域表面等离子体共振（LSPR）纳米探针，该探针以金/银核壳纳米棒作为光学纳米基底来检测汞离子（Hg）。在有氧气存在的室温条件下，硫化物能迅速与银原子反应生成硫化银（AgS）。纳米棒表面从银壳向硫化银的转变导致其LSPR吸收带移向更长波长，这归因于它们不同的折射率。有趣的是，形态也从棒状变为哑铃状。然而，在有汞存在的情况下，这种形态转变受到抑制，因为硫化物在与银原子反应之前先与游离汞发生了反应。随着汞浓度的增加，硫化银的量减少，吸收带的位移也减小。基于这种“是否从棒状变为哑铃状”的形状变化，借助紫外可见吸收光谱建立了一种灵敏且具选择性的LSPR纳米探针。该探针检测汞的检测限低至13 nM。通过检测加标水样中的汞来评估该探针在复杂样品中的检测效率。
