[Research Progress on the Extraction, Qualitative, and Quantitative Methods of Microplastics in Biological Samples]

Microplastics （MPs）, which usually refer to plastic fragments, particles, or fibers with a diameter or length of less than 5 mm, are contaminants of emerging concern （CECs） that have a significant impact on the ecological system. MPs have been widely detected in the soil, surface water, ocean, and atmosphere. These MPs could accumulate in organisms via absorption and/or ingestion, transfer along the food chain, and ultimately pose a threat to the health of higher trophic organisms and even human beings. Therefore, the determination of MPs types and contents in organisms is important for understanding the accumulation of MPs in organisms and their potential ecological risks. Hence, in this study, we focus on the analysis of MPs in biological samples. After researching the domestic and foreign literature, the basic principles, suitable application conditions, as well as the advantages and disadvantages of each method used in four processes of MPs analysis, including biological sample collection, MPs extraction （including the digestion of biological samples and separation of MPs from digestion solutions）, and qualitative and quantitative analysis, were discussed. On this basis, a combination of different analysis methods is proposed to improve the detection accuracy of MPs analysis in biological samples, which requires further investigation in the field of MPs analysis in biological samples. Meanwhile, more efforts should be exerted on the investigation of the standard method used in biological sample pretreatment and MPs analysis.