Superhydrophobic Surface-Enhanced Raman Spectroscopy (SERS) Substrates for Sensitive Detection of Trace Nanoplastics in Water

Nanoplastics, emerging as pervasive environmental pollutants, pose significant threats to ecosystems and human health due to their small size and potential toxicity. However, detecting trace levels of nanoplastics remains challenging because of limitations in the current analytical methods. Herein, we propose a method that combines superhydrophobic enrichment with SERS analysis for detecting trace nanoplastics in aqueous environments. Superhydrophobic SERS substrates were prepared by using a liquid-liquid self-assembly method. The superhydrophobicity facilitated analyte enrichment, and monolayer Au nanoparticles (AuNPs) enhanced the Raman signals. The detection limit for Raman probe crystal violet (CV) using this substrate reached nanomolar (10^-9 M), with an RSD of 9.96% across a 40 × 40 μm² area (441 spots), demonstrating excellent sensitivity and reproducibility. This method successfully detected polystyrene (PS) plastics ranging from 30 to 1000 nm in water with concentrations as low as 0.03 μg/mL. Additionally, nanoscale polyethylene terephthalate (PET) particles were detected in bottled water samples. This approach offers a promising platform for analyzing trace nanoplastics in environmental water samples and addresses the needs of environmental monitoring.