Given the strong hydration propensity of fluoride ions, it is difficult to detect fluoride, especially inorganic fluoride, in aqueous samples. Resolving the issue of fluoride detection in aqueous samples is a scientific undertaking of great practical significance. Herein, we propose a new method for the sensitive and selective detection of fluoride in aqueous samples without the addition of organic solvents. The method involves surface-enhanced Raman spectroscopy using 1,4-diketo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP) compounds and Ag nanoparticles. The method is based on a diketopyrrolopyrrole compound linked to 1-butyl iodide (DPP1), which can sense fluoride sensitively and selectively. When DPP1 was combined with Ag NPs and reacted with tetrabutylammonium fluoride or inorganic fluoride in aqueous samples, an obvious Raman enhancement was obtained at the excitation wavelength of 633 nm. This response arises because the introduction of fluoride anions into the system changes the molecular orientation of DPP1 on the Ag NP substrate from horizontal to vertical, inducing a signal enhancement in the Raman spectrum. This system can detect inorganic fluoride at concentrations as low as 1.0 μmol L⁻¹ (0.018 ppm), which is far below the public health service recommended levels for drinking water (0.7–1.2 ppm). Furthermore, using the proposed method, a linear response for fluoride in the concentration range of 1.0 × 10⁻³–1.0 × 10⁻⁶ mol L⁻¹ was obtained, which makes fluoride detection possible in practical samples, such as fluoride-containing toothpaste.

由于氟化物离子具有很强的水化倾向，因此很难检测到水样中的氟化物，尤其是无机氟化物。解决含水样品中氟化物的检测问题是一项具有重大现实意义的科学工作。本文中，我们提出了一种无需添加有机溶剂即可灵敏和选择性地检测水性样品中氟化物的新方法。该方法涉及使用1,4-二酮-3,6-二苯基吡咯并[3,4- c]吡咯（DPP）化合物和Ag纳米颗粒。该方法基于与1-丁基碘化物（DPP1）连接的二酮吡咯并吡咯化合物，该化合物可以敏感和选择性地感应氟化物。当DPP1与Ag NPs结合并与四丁基氟化铵或无机氟化物在水性样品中反应时，在633 nm的激发波长下获得了明显的拉曼增强。出现此响应的原因是，将氟离子引入系统后，Ag NP基板上DPP1的分子取向从水平变为垂直，从而在拉曼光谱中引起信号增强。该系统可以检测低至1.0μmolL ^-1的无机氟化物（0.018 ppm），远低于公共卫生服务部门推荐的饮用水水平（0.7–1.2 ppm）。此外，使用所提出的方法，可以获得浓度范围为1.0×10 ^-3 –1.0×10 ^-6  mol L ^-1的氟化物的线性响应，这使得在含氟牙膏等实际样品中进行氟化物检测成为可能。 。