Matrix preparation and workflow for microplastics analysis in soil.

One of the main difficulties in microplastic (MP) research is the lack of standardized, real-world methods such as matrix blank and simultaneous tracking of polymer particles for enumeration. Building on a previous study, a matrix preparation and experimental workflow for soil matrices is presented that addresses the challenges of purification to allow subsequent analysis using Nile Red-stained MPs as a surrogate. Key steps include peroxide digestion and density separation (NaI) followed by centrifugation for low density polyethylene (LDPE) and polyvinyl chloride (PVC) surrogates to assess recoveries in terms of number and size, based on fluorescence microscopy and Raman spectroscopy.