Detection methods for emerging microplastics

The footprint of microplastics (MPs) has spread all over the world and has attracted widespread attention. Studies have shown that MPs not only pose a threat to the growth of organisms but also can absorb emerging pollutants, thereby promoting the widespread spread of emerging pollutants and bringing greater ecological risks to the environment. The qualitative and quantitative detection of MPs is the basis for studying the ecological risk of MPs. This chapter summarizes the methods of MPs from extraction and purification to detection. The extraction of MPs is mainly through membrane filtration and density flotation, while the purification of MPs includes acid-base digestion, advanced oxidation, and enzyme treatment. Fourier-transform infrared spectroscopy and Raman spectroscopy are two commonly used mature MPs detection technologies. Based on the improvement of these two basic technologies, more and more efficient MPs detection technologies with lower detection concentration limit and smaller detection size have emerged. Laser direct infrared spectroscopy has also been increasingly applied to the detection of MPs in the environment. This chapter also summarizes the occurrence of MPs in freshwater, seawater sediments, and different water treatment systems. Finally, the application of model analysis and machine learning algorithms in the analysis of MPs distribution and migration in the actual environment is summarized. At present, although a complete environmental MPs extraction and analysis process has been constructed there is still a lack of unified detection and reporting standards. Thus we put forward some suggestions on the improvement direction of MPs detection methods.