Simple and Efficient Laser-Induced Evaporation Assembly Method to Fabricate SERS Optical Fiber Probe for Detection of PAHs

Surface-enhanced Raman scattering (SERS) is a powerful tool for trace substance detection and analysis. However, traditional SERS detection based on substrates usually separates sampling and detection, which are time consuming and lack portability for practical applications. In this study, we developed a SERS fiber optic probe using a simple and efficient laser-induced evaporation assembly method. By direct immersion of the fiber in a microliter colloidal solution of silver nanocubes (Ag NCs) under laser induction, a monolayer of uniform and dense Ag NCs was modified on the end face of the optical fiber. The fabricated SERS fiber optic probe demonstrated excellent reproducibility and stability with a detection limit of less than 10^–8 M for the 4-mercaptobenzoic acid (4-MBA), with the intensity of its two characteristic Raman peaks showing a high linear correlation with the logarithm of the concentration. Furthermore, by combining Ag NCs with bromide ions, the Ag-Br NCs fiber optic probe we fabricated and exhibited outstanding performance in detecting organic pollutants polycyclic aromatic hydrocarbons (PAHs). This work may have potential significance in broadening the application field of SERS fiber-optic probes.