Department of Solid State Engineering, University of Chemistry and Technology, Technická 5, 16628, Prague, Czech Republic.
Department of Solid State Engineering, University of Chemistry and Technology, Technická 5, 16628, Prague, Czech Republic; Materials Centre, Faculty of Science, J. E. Purkyně University, Pasteurova 3544/1, 400 96, Ústí nad Labem, Czech Republic.
Chemosphere. 2024 Sep;364:143149. doi: 10.1016/j.chemosphere.2024.143149. Epub 2024 Aug 23.
Human activity is the cause of the continuous and gradual grooving of environmental contaminants, where some released toxic and dangerous compounds cannot be degraded under natural conditions, resulting in a serious safety issue. Among them are the widely occurring water-soluble perfluoroalkyl and polyfluoroalkyl substances (PFAS), sometimes called "forever chemicals" because of the impossibility of their natural degradation. Hence, a reliable, expressive, and simple method should be developed to monitor and eliminate the risks associated with these compounds. In this study, we propose a simple, express, and portable detection method for water-soluble fluoro-alkyl compounds (PFOA and GenX) using mutually complementary methods: electrochemical impedance spectroscopy (EIS) and surface-enhanced Raman spectroscopy (SERS). To implement our method, we developed special substrates based on porous silicon with a top-deposited plasmon-active Au layer by subsequently grafting -CH-NH chemical moieties to provide surface affinity toward negatively charged water-soluble PFAS. Subsequent EIS utilization allows us to perform semiquantitative detection of PFOA and GenX up to 10 M concentration because surface entrapping of PFAS leads to a significant increase in the electrode-electrolyte charge-transfer resistance. However, distinguishing by EIS whether even PFAS were entrapped was impossible, and thus the substrates were subsequently subjected to SERS measurements (allowed by surface plasmon activity due to the presence of a porous Au layer), clearly indicating the appearance of characteristic C-F vibration bands.
人类活动是环境污染物不断累积和逐渐形成沟槽的原因，其中一些释放的有毒有害物质在自然条件下无法降解，造成严重的安全问题。其中广泛存在的水溶性全氟烷基和多氟烷基物质（PFAS）有时被称为“永久化学物质”，因为它们无法自然降解。因此，应该开发一种可靠、表达力强且简单的方法来监测和消除与这些化合物相关的风险。在本研究中，我们提出了一种使用相互补充的方法：电化学阻抗谱（EIS）和表面增强拉曼光谱（SERS），来检测水溶性氟烷基化合物（PFOA 和 GenX）的简单、快速且便携的检测方法。为了实现我们的方法，我们开发了特殊的基于多孔硅的基底，其顶部沉积有等离子体活性的 Au 层，随后通过接枝-CH-NH 化学基团来提供对带负电荷的水溶性 PFAS 的表面亲和力。随后的 EIS 利用允许我们对 PFOA 和 GenX 进行半定量检测，浓度高达 10 M，因为 PFAS 的表面捕获会导致电极-电解质电荷转移电阻显著增加。然而，通过 EIS 无法区分是否甚至 PFAS 被捕获，因此随后对基底进行了 SERS 测量（由于多孔 Au 层的存在，表面等离子体活性允许进行测量），清楚地表明出现了特征的 C-F 振动带。
