A Powerful Method for In Situ and Rapid Detection of Trace Nanoplastics in Water—Mie Scattering

The pervasive presence of nanoplastics (NPs) in environmental media has raised significant concerns regarding their implications for environmental safety and human health. However, owing to their tiny size and low level in the environment, there is still a lack of effective methods for measuring the amount of NPs. Leveraging the principles of Mie scattering, a novel approach for rapid in situ quantitative detection of small NPs in low concentrations in water has been developed. A limit of detection of 4.2 μg/L for in situ quantitative detection of polystyrene microspheres as small as 25 nm was achieved, and satisfactory recoveries and relative standard deviations were obtained. The results of three self-ground NPs showed that the method can quantitatively detect the concentration of NPs in a mixture of different particle sizes. The satisfactory recoveries (82.4% to 110.3%) of the self-ground NPs verified the good anti-interference ability of the method. The total concentrations of the NPs in the five brands of commercial bottled water were 0.07 to 0.39 μg/L, which were directly detected by the method. The proposed method presents a potential approach for conducting in situ and real-time environmental risk assessments of NPs on human and ecosystem health in actual water environments. Due to the widespread presence of nanoplastics (NPs) in the environment, they pose a potential risk to human and ecosystem health. The proposed method allows for the rapid quantitative detection of NPs as small as 25 nm, irrespective of their size, thereby contributing to the advancement of NPs detection methods. This approach requires no preprocessing, supports the online detection of NPs in the environment, and is capable of directly and rapidly quantifying the concentration of NPs. It serves as a potential tool for in situ assessment of the risk of human and ecosystem exposure to NPs in the environment.