ToF-SIMS characterization of microplastics in soils

Microplastics pollution is becoming one of the most serious threats to the surface ecosystem of the earth; it is widespread in oceans, rivers, sediments, soils, and organisms. It is a growing concern as an environmental pollutant, which currently has no clear detection standard. Detection methods still need to be constantly supplemented and improved. This study explored a novel method called time-of-flight secondary ion mass spectrometry (ToF-SIMS) in this field. Four types of microplastics in farmland soils, namely, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polyamide 6, were successfully identified in terms of particle size and abundance by combining the high molecular specificity with ion imaging capability of ToF-SIMS. The procedure based on ToF-SIMS analysis also provides a methodological reference and basic data for the investigation and research of microplastics in soil, coastal beaches, and sediment.