Breaking the Size Barrier: SERS-Based Ultrasensitive Detection and Quantification of Polystyrene Plastics in Real Water Samples

Plastic pollution has emerged as a critical global environmental challenge, posing substantial risks to ecosystems' stability, biodiversity conservation, and public health protection. However, technique limitations persist in detecting and analyzing plastic particles within complex environmental matrices. This study introduces an ultrasensitive surface-enhanced Raman spectroscopy (SERS)-based method for detecting and precisely quantifying polystyrene (PS) plastic particles of various sizes in real-world aqueous samples. The developed SERS platform integrates urchin-like silver nanoparticles, generating high-density SERS hotspots, with a slippery polydimethylsiloxane (PDMS) brush surface for effective analyte enrichment. The synergistic combination achieves exceptional detection performance for dichloromethane (DCM)-dispersed polystyrene plastic particles across broad size ranges, demonstrating a remarkable detection limit of 2.57 × 10^-5 mg/mL. The established quantitative relationship follows log <i>I</i> = 0.4501 log <i>C</i> + 4.1869 (<i>R</i>² = 0.9899), confirming excellent analytical reliability. This advancement provides a robust analytical framework for environmental monitoring applications, particularly offering a novel approach for detecting microplastics (MPs) and nanoplastics (NPs) in real water samples.