Abstract Prevalent contamination of water by cadmium ion (Cd2+) brings environmental risk, which threatening to human health including renal dysfunction, reduced lung capacity, and some cancers. It calls for rapid, sensitive and selective protocol to analyze Cd2+ on field. In this work, specific Raman probe is rationally designed by gold nanoparticles (AuNPs) functionalized with tripeptide glutathione (GSH) and Rhodamine 6G (R6G) (denoted as R6G/GSH/AuNPs), which is explored for indirectly determining trace Cd2+ in river water. Based on chelating interaction between GSH and Cd2+ to form tetrahedral Cd(SG)4, which trends easy detachment from R6G/GSH/AuNPs. With increasing Cd2+ concentration, the Raman probe without protection of GSH happens due aggregation and Raman signal of R6G increases correspondingly. The R6G/GSH/AuNPs-based Raman detection of Cd2+ in river water shows rapidness, excellent sensitivity, selectivity and good repeatability. Limit of detection of 10 ppb with a widely linear range of 0.5–20 ppm could be achieved. It could be perspective that such Raman probe could be extended to be used for on-site monitoring trace Cd2+ in river water system.

中文翻译：

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拉曼探测痕量镉离子的表面反应策略

摘要 镉离子（Cd2+）对水体的普遍污染带来了环境风险，威胁着人类健康，包括肾功能障碍、肺活量降低和某些癌症。它需要快速、灵敏和选择性的协议来分析现场 Cd2+。在这项工作中，特定的拉曼探针是由三肽谷胱甘肽 (GSH) 和罗丹明 6G (R6G)（表示为 R6G/GSH/AuNPs）功能化的金纳米粒子 (AuNPs) 合理设计的，用于间接测定河水中的痕量 Cd2+ . 基于 GSH 和 Cd2+ 之间的螯合相互作用形成四面体 Cd(SG)4，其趋向于与 R6G/GSH/AuNPs 容易分离。随着Cd2+浓度的增加，没有GSH保护的拉曼探针发生聚集，R6G的拉曼信号相应增加。基于 R6G/GSH/AuNPs 的河水中 Cd2+ 拉曼检测显示出快速、出色的灵敏度、选择性和良好的重复性。可以实现 10 ppb 的检测限，线性范围为 0.5-20 ppm。可以预见，这种拉曼探针可以扩展到用于河水系统中痕量Cd2+的现场监测。