Separation and Analysis of Micro/Nanoplastics in Environmental Samples
The vast amount of plastic waste emitted into the environment and the increasing concern of potential harm to wildlife has made micro/nanoplastic pollution a growing environmental concern. Small particles are especially concerning because of their high specific surface area for sorption of contaminants, as well as their potential to translocate in the bodies of organisms. These same small particles are challenging to separate and identify in environmental samples because their size makes handling and observation difficult.
Currently employed passive density and size separation techniques to isolate plastics from environmental samples are not well suited to separate micro/nanoplastics. Passive flotation is hindered by the low buoyancy of small particles as well as the difficulty in handling small particles on the surface of flotation media . These techniques can be improved by adapting active density separation from cell biology and taking advantage of surface-interaction-based separations from analytical chemistry. Furthermore, plastic pollution is often challenging to quantify in complex matrices such as biological tissues and wastewater. Biological and wastewater samples are important matrices that represent key points in the sources and fate, respectively, of plastic pollution. In such samples, protocols need to be optimized to increase throughput, reduce contamination potential and avoid plastics destruction during sample processing.
Post-isolation, micro/nanoplastics from environmental samples should be characterized for both detection and quantification levels. With existing techniques, micro/nanoplastics are difficult to characterize or even detect as their small size and low mass offer restricted signals for visual and spectroscopic estimation. Each of these techniques involve trade-offs in throughput, spatial resolution and sensitivity. Multiple analytical techniques applied in tandem are likely to be required for accurate identification and complete quantification of micro/nanoplastics in environmental samples .