Hydrophobicity–water/air–based enrichment cell for microplastics analysis within environmental samples: A proof of concept

The analysis of microplastics in sediments, soils or beach samples is commonly paired with a separation step to enrich microplastics or to remove non-plastics, respectively. Those steps are often very time consuming and are performed in presence of high concentrated solvents. The latter are also suspected to corrode or decompose the analyte particles, which hamper further identification processes. This paper describes a new fast and effective microplastics separation apparatus for analytical issues that was based on hydrophobic adhesion of microplastics and fine air bubbles. The presented prototype could successfully enrich over 90 %(wt) of 30ppm(w) microplastics in 200 g sand in 20 min. Additionally, it could be demonstrated that the new separation technique was very suitable for further microplastics identification by FTIR microscopy. In this context, a sample with different polymers and matrix components was analyzed and the results were presented within this article. • Microplastics were enriched selectively by hydrophobic adhesion. • No additional chemicals except water and air were used. • Separation took only 20 min and 90 %(wt)of microplastics were recovered.