Quantifying Nanoplastics in Soil-Cultured Plants Based on a Microcombustion Calorimeter

Nanoplastics have been detected in a variety of plants and threaten plant growth. To further investigate the physiological damage of nanoplastics to plants and their translocation in plants, it is crucial to quantify the nanoplastics in the plant. However, until now, no studies have reported on how to quantify nanoplastics in soil-cultured plants. Here, we proposed to determine the polyethylene (PE) and poly(methyl methacrylate) (PMMA) contents in soil-cultured plants using a microcombustion calorimeter (MCC). Since the thermal properties of nanoplastics were different from those of plants and soil, this method was not affected by the environmental background. The linear relationships were developed between the sample total heat release (THR) and nanoplastic proportions. Generally, the application of MCC to quantify PE and PMMA resulted in low detection limits (LODs), quantification limits (LOQs), and high spiked recoveries. The method also achieved a high level of accuracy (relative standard deviation and A type uncertainty), demonstrating the feasibility of the proposed method. This is the first report to quantify nanoplastics in soil-cultured plants based on MCC. It provides the possibility for rapid quantification of nanoplastics in plants and thus allows in-depth research of the behavior of nanoplastics in a soil–plant system.