Improved separation and quantification method for microplastic analysis in sediment: A fine-grained matrix from Arctic Greenland

Microplastic analysis requires effective separation and purification methods, which greatly depend on the matrix and target particle size. Microplastics-sediment extraction usually involves intermediate steps, increasing processing time and particle loss, particularly for particles <100 mu m. Here, we propose an improved separation and quantification method for fine-grained sediment that minimizes microplastic loss by reducing intermediate steps. First, the sample is treated with CH3COOH, KOH and NaClO, and only transferred for the density separation (ZnCl2). The extraction efficiency, visually evaluated on spiked samples, was higher than 90% for particles >100 mu m and 83% for 63-75 mu m particles. This indicates that a sequential extraction method reduces the risk of particle loss, particularly of the small size fraction. Comparatively, the extraction of ABS particles (20-100 mu m) was low (30%) but the recovery, assessed via mu FTIR, was higher (55%). Additionally, the proposed method can be adapted to other sediment types and environmental matrices.

Automated summary

This study proposes an improved method for separating and quantifying microplastics in sediment, which minimizes particle loss by reducing intermediate steps. The results demonstrate that this sequential extraction method effectively retains particles of different sizes, with a lower risk of loss for smaller particles.