Zhang Huijuan, Wang Dong, Zhang Duan, Zhang Tongtong, Yang Longkun, Li Zhipeng
The Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Department of Physics, Capital Normal University, Beijing 100048, P.R. China.
ACS Appl Mater Interfaces. 2022 Jan 12;14(1):2211-2218. doi: 10.1021/acsami.1c17832. Epub 2021 Dec 29.
Mercury(II) ions are causing serious environmental pollution and health damage. Developing a simple, rapid, and sensitive sensor for Hg detection is of great significance. Herein, we demonstrate an I-functionalized surface-enhanced Raman scattering (SERS) substrate for rapid and sensitive Hg sensing on a highly integrated microfluidic platform. Based on the combination reaction between I and Hg, the Hg sensing is achieved via the SERS intensity "turn-off" strategy, where HgI precipitation is formed on an SERS substrate interface, dissociating the Raman reporters that coadsorbed with I. Owing to the strong binding constant between I and Hg, our I-functionalized substrate demonstrates a very fast sensing response (∼150 s). Through reliable in situ SERS detection, a robust calibration curve between the "turn-off" signal and "lg" is obtained in a broad concentration range of 10 to 10 M. Additionally, the detectable Hg concentration can be as low as 1 fM. The good selectivity toward Hg is also verified by testing about a dozen common metal ions in water, such as K, Na, Ca, Mg, and so forth. Furthermore, we apply the SERS sensor for real tap and lake water sample detection, and good recoveries of 113, 97, and 107% are obtained. With its advantages of high integration, simple preparation, fast response, high sensitivity, and reliability, the proposed I-functionalized SERS sensor microfluidic chip can be a promising platform for real-time and on-site Hg detection in natural water.
汞（II）离子正在造成严重的环境污染和健康损害。开发一种用于汞检测的简单、快速且灵敏的传感器具有重要意义。在此，我们展示了一种在高度集成的微流控平台上用于快速灵敏汞传感的碘功能化表面增强拉曼散射（SERS）基底。基于碘与汞之间的结合反应，通过SERS强度“猝灭”策略实现汞传感，即在SERS基底界面形成碘化汞沉淀，使与碘共吸附的拉曼报告分子解离。由于碘与汞之间具有很强的结合常数，我们的碘功能化基底表现出非常快速的传感响应（约150秒）。通过可靠的原位SERS检测，在10⁻¹⁰至10⁻⁶ M的宽浓度范围内获得了“猝灭”信号与“lg”之间的稳健校准曲线。此外，可检测的汞浓度低至1 fM。通过测试水中的十几种常见金属离子（如钾、钠、钙、镁等）也验证了对汞具有良好的选择性。此外，我们将该SERS传感器应用于实际自来水和湖水样品检测，回收率分别为113%、97%和107%。所提出的碘功能化SERS传感器微流控芯片具有高集成度、制备简单、响应快速、灵敏度高和可靠性强等优点，有望成为天然水中汞实时现场检测的平台。
