Development of multifunctional 3D nanostructure substrate with solid phase extraction and surface-enhanced Raman...

Surface-enhanced Raman scattering (SERS) is a powerful molecular fingerprinting tool, yet its practical application in complex matrices is often hindered by severe interference and low analyte concentrations. In this study, we developed a multifunctional, low-cost Glass Fiber SERS (GF-SERS) platform that integrates solid-phase extraction (SPE) and high-sensitivity SERS detection for rapid food and environmental safety assessments. By employing a two-stage sputtering, atmospheric thermal annealing, and oxygen plasma treatment, we achieved a high-density distribution of silver nanoparticle (AgNP) hotspots with controlled nanogaps, ensuring exceptional signal reproducibility (RSD = 9%). The integration of SPE functionality directly into the GF-SERS substrate enables a simplified "capture-to-detection" workflow, where the porous fiber matrix serves as both a microextraction medium to enrich targets and a filter to mitigate matrix effects from complex samples like reconstituted milk and pond water. Our platform demonstrates a wide linear detection range for malachite green (MG), achieving a low limit of detection (LOD) of 0.76 ppb and a high analytical enhancement factor (AEF) of 1.28 x 10⁵. This integrated SPE-SERS strategy provides a robust solution for the on-site identification of illegal additives in diverse and challenging analytical scenarios.