Identification of Poly(ethylene terephthalate) Nanoplastics in Commercially Bottled Drinking Water Using Surface-Enhanced Raman Spectroscopy

Micro/nanoplastics have emerged as global contaminants of serious concern to human and ecosystem health. However, identification and visualization of microplastics and particularly nanoplastics have remained elusive due to the lack of feasible and reliable analytical approaches, particularly for trace nanoplastics. Here, an efficient surface-enhanced Raman spectroscopy (SERS)-active substrate with triangular cavity arrays is reported. The fabricated substrate exhibited high SERS performance for standard polystyrene (PS) nanoplastic detection with size down to 50 nm and a detection limit of 0.001% (1.5 × 10¹¹ particles/mL). Poly(ethylene terephthalate) (PET) nanoplastics collected from commercially bottled drinking water were detected with an average mean size of ∼88.2 nm. Furthermore, the concentration of the collected sample was estimated to be about 10⁸ particles/mL by nanoparticle tracking analysis (NTA), and the annual nanoplastic consumption of human beings through bottled drinking water was also estimated to be about 10¹⁴ particles, assuming water consumption of 2 L/day for adults. The facile and highly sensitive SERS substrate provides more possibilities for detecting trace nanoplastics in an aquatic environment with high sensitivity and reliability.