Hetero-charge-based surface enhanced Raman spectroscopy: An in situ rapid detection strategy for real marine nanoplastics

As a worldwide pollution problem, the investigation and detection of marine nanoplastics (plastics <1 µm) have attracted considerable attention. However, current detection methods for marine nanoplastic specimens require membrane filtration or drying enrichment as a pretreatment procedure. Developing a rapid detection method to directly detect nanoplastics in aqueous solutions without any pretreatment is an enormous challenge. In this study, an in situ rapid hetero-charge-based surface-enhanced Raman spectroscopy (SERS) nanoplastics detection strategy is proposed, and two modulated charged gold nano sphere particles (AuNPs) are designed for nanoplastics detection in situ. According to the electric charge attraction effect and the customized AuNPs, the SERS characteristic peak signal of the polystyrene nanoplastics (PS NPs) was clearly identified, and the lowest detected concentration was 0.1 µg/mL in artificial seawater. Meanwhile, this detection strategy was utilized for a real marine specimen which was successfully detected and identified the existence of PS, and the estimated concentration of this specimen was 1.544E-4 µg/mL. These results indicate that this in situ SERS detection strategy could be utilized for the further analysis of both charged nanoplastics under real marine conditions.