State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000, China.
Analyst. 2017 Sep 8;142(18):3459-3467. doi: 10.1039/c7an00675f.
In shell-isolated nanoparticle (NP)-enhanced Raman spectroscopy (SHINERS), traditional metal oxide-based shells have inferior chemical inertness, they require strict preparation conditions, and lack specific groups, which lead to their poor selectivity toward target molecules. In this study, ultrathin and compact gold (Au)@polydopamine (PDA) SHINERS NPs were successfully fabricated by a simple self-polymerization technique. High wrapping tendency of PDA, a multifunctional biopolymer, favored the fabrication process. Au@PDA NPs exhibited a typical shell-isolated effect, i.e., Au@PDA NPs with a thick shell (more than 2.3 nm) showed a lower SERS activity, while those with an ultrathin (1.3 nm) shell exhibited higher SERS activity compared to uncoated Au NPs. The Au@PDA SHINERS substrate shows high performance in terms of sensitivity, uniformity, and stability. The relative standard deviations (RSDs) of SERS intensities from ten positions on the same substrate were less than 4%. Their Raman intensities dropped by only 15% over two months. More importantly, the Au@PDA (1.3 nm) SHINERS substrate exhibited high SERS activity for label-free and quantitative detection of benzotriazole (BTA), an important corrosion inhibitor, through utilizing a presumed π-π stacking interaction. A broad linear range from 10 to 10 M was achieved with a low detection limit (LOD) of 1 nM (0.119 μg L). The LOD was not only significantly lower than the maximum allowable level (20 μg L) of the Australian government water guide, but also lower than that of some modern methods such as fluorescence, liquid chromatography, and gas chromatography coupled with mass spectrometry. Furthermore, the substrate showed excellent discrimination against other compounds with a single aromatic ring. It is expected that the Au@PDA SHINERS substrate will offer great potential for analysis application in a complicated environmental system.
在壳层隔离纳米粒子（NP）增强拉曼光谱（SHINERS）中，传统的基于金属氧化物的壳层化学惰性差，需要严格的制备条件，并且缺乏特定基团，导致它们对目标分子的选择性差。在这项研究中，通过简单的自聚合技术成功制备了超薄且致密的金（Au）@聚多巴胺（PDA）SHINERS NPs。多功能生物聚合物 PDA 的高包裹倾向有利于制备过程。Au@PDA NPs 表现出典型的壳层隔离效应，即具有较厚壳层（超过 2.3nm）的 Au@PDA NPs 表现出较低的 SERS 活性，而具有超薄（1.3nm）壳层的 Au@PDA NPs 表现出比未涂覆的 Au NPs 更高的 SERS 活性。Au@PDA SHINERS 基底在灵敏度、均匀性和稳定性方面表现出高性能。同一基底十个位置的 SERS 强度的相对标准偏差（RSD）小于 4%。在两个月的时间内，它们的拉曼强度仅下降了 15%。更重要的是，通过利用假定的π-π堆积相互作用，Au@PDA（1.3nm）SHINERS 基底对苯并三唑（BTA）这种重要的缓蚀剂进行无标记和定量检测表现出高 SERS 活性。实现了从 10 到 10 M 的宽线性范围和低检测限（LOD）为 1 nM（0.119μg L）。LOD 不仅明显低于澳大利亚政府水指南规定的最大允许水平（20μg L），而且也低于荧光、液相色谱、气相色谱和质谱联用等一些现代方法的检测限。此外，该基底对具有单个芳环的其他化合物具有出色的区分能力。预计 Au@PDA SHINERS 基底将为复杂环境系统的分析应用提供巨大潜力。
