Hollow raspberry-like nanoaggregates for sensitive SERS detection of PAHs in water

• Hollow polystyrene spheres are decorated with gold nanoparticles to form raspberry-like nanoaggregates. • Surface functionalization controls gold coverage, optimizing hotspots for enhanced SERS detection. • Hollow raspberry-like nanoaggregates enhance ultra-sensitive SERS detection of PAHs in water. • Detection limits achieved for pyrene, fluorene, and benzo[a]anthracene are exceptionally low. Polycyclic aromatic hydrocarbons (PAHs) are significant environmental contaminants with considerable health risks, emphasizing the need for effective monitoring and identification. On-site detection of PAHs using surface-enhanced Raman scattering (SERS) remains challenging due to their weak adsorption on substrates and potential interference from the substrates themselves. To address these challenges, we developed hollow raspberry-like plasmonic nanoaggregates made of functionalized-polystyrene hollow microspheres (HM) decorated with gold nanoparticles (Au NPs). These nanoaggregates feature a hydrophobic inner cavity that effectively enriches PAHs, improving detection sensitivity. Through enhanced plasmonic coupling by carefully controlling Au NPs coverage on polystyrene (PS) surfaces, functionalizing the amino groups on the microsphere surface, and fine-tuning the Au NP to PS ratio, our method achieved detection limits of 4 × 10 −8 M for pyrene, 6 × 10 −7 M for fluorene, and 4 × 10 −7 M for benzo[a]anthracene. Moreover, this approach was effectively utilized for detecting PAHs in both Yellow River water and tap water. This study highlights the capabilities of hollow raspberry-like plasmonic nanoaggregates for qualitative and quantitative analysis of PAHs, thereby broadening the use of advanced nanomaterials in monitoring environmental water quality.