College of Chemistry, Nanchang University, Nanchang 330031, China.
College of Chemistry, Nanchang University, Nanchang 330031, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Mar 5;192:174-180. doi: 10.1016/j.saa.2017.11.022. Epub 2017 Nov 8.
In this study, we have developed a method for rapid, highly efficient and selective detection of melamine. The negatively charged citrate ions form an electrostatic layer on gold nanoparticles (AuNPs) and keep the NPs dispersed and stable. When citrate-capped AuNPs were further modified with Triton X-100, it stabilized the AuNPs against the conditions of high ionic strength and a broad pH range. However, the addition of melamine caused the destabilization and aggregation of NPs. This may be attributed to the interaction between melamine and the AuNPs through the ligand exchange with citrate ions on the surface of AuNPs leading Triton X-100 to be removed. As a result, the AuNPs were unstable, resulting in the aggregation. The aggregation induced a wine red-to-blue color change, and a new absorption peak around 630nm appeared. Triton X-100-AuNPs could selectively detect melamine at the concentration as low as 5.1nM. This probe was successfully applied to detect melamine in milk. Furthermore, paper-based quantitative detection system using this colorimetric probe was also demonstrated by integrating with a smartphone.
在这项研究中，我们开发了一种快速、高效、选择性检测三聚氰胺的方法。带负电荷的柠檬酸根离子在金纳米粒子（AuNPs）上形成一层静电层，使 NPs 保持分散和稳定。当用 Triton X-100 进一步修饰带负电荷的柠檬酸根离子封端的 AuNPs 时，它可以稳定 AuNPs，使其能够耐受高离子强度和宽 pH 范围的条件。然而，三聚氰胺的加入会导致 NPs 的失稳和聚集。这可能归因于三聚氰胺与 AuNPs 之间的相互作用，通过配体交换将柠檬酸根离子从表面上交换下来，导致 Triton X-100 被去除。结果，AuNPs 变得不稳定，导致聚集。聚集诱导了从酒红色到蓝色的颜色变化，并且在大约 630nm 处出现了新的吸收峰。Triton X-100-AuNPs 可以在低至 5.1nM 的浓度下选择性地检测三聚氰胺。该探针成功地应用于检测牛奶中的三聚氰胺。此外，还通过与智能手机集成，展示了基于这种比色探针的纸质定量检测系统。
