Binary solvent extraction of microplastics from a complex environmental matrix

Abstract

Separating microplastics (MPs) (smaller particle size, < 1 mm) from complex environmental samples such as particulate organic matter (POM) is challenging, particularly for polyethylene and polypropylene, which are buoyant like POM. It is often done using a time‐consuming procedure, often with hazardous waste generation. We developed a simple, low‐cost procedure using a binary solvent mixture (ethanol–water) followed by water solvation to separate MPs from estuarine POM and surface water. The isolated MPs were quantified and characterized using μFT‐IR and scanning electron microscopy, with particle sizes ranging from 30 to 2500 μm and percentage mass from 2.62–21.3% wt/wt in POM and 0.04–0.42% wt/vol for surface water, respectively. Different polymer types, colors, and shapes were observed. Method recovery assessed using spiking yielded 89–93.1% and the method was validated by visual sorting with dye staining. This method is low‐cost, simple, and aligns with Green Chemistry approaches while efficiently separating plastics of various particle sizes, shapes, and compositions. Furthermore, this low‐cost approach and the near‐universal availability of ethanol make this method more accessible in research and education throughout regions of the world where plastic debris is a major challenge but resources to study the problem are limited.