One-stop quantification of microplastics and nanoparticles based on meniscus self-assembly technology

Micro-nano plastics (MNPs) pollution is currently a hot topic of global concern. However, there is still a lack of reliable analytical methods for completely quantitative analysis of MNPs, especially nanoplastics. This study proposes meniscus self-assembly enrichment method, which deposits nanoplastics more uniformly in a specific area. The meniscus self-assembly method greatly overcomes the agglomeration or dispersion of nanoplastics caused by traditional enrichments, and facilitates particles counting. This study investigates the effect of key parameters (e.g. time and initial concentration) on meniscus self-assembly enrichment performance. Besides, due to the large size difference between MNPs, it leads to incomplete quantification analysis when MNPs are counted at the same scale. In response to this problem, this study proposes a one-stop method to count MNPs separately through filtering. The plastics (>1 μm) are collected on the filter paper, then plastics (<1 μm) in the filtrate are homogeneously enriched by meniscus self-assembly, and finally statistically counted by scanning electron microscopy (SEM). The migration of MNPs from take-out plastic containers are detected, with microplastics of 460.55 particles/mL and nanoplastics of 4196.61 particles/mL found. The method has the advantages of saving time and effort, economic efficiency and comprehensive statistics compared with the traditional method.