A Comparison of Different Approaches for Characterizing Microplastics in Selected Personal Care Products

Abstract

Any uncertainty in determining numbers of microplastics in the environment may be barrier to assessing their impact and may stem from various aspects of methodologies used to quantify them. This paper undertakes a comparison of approaches to quantify and characterize microplastics in four personal care products. The aim was to not only determine how many particles were present, but to assess any differences due to the methods used. Counting of extracted microplastics was undertaken using particle size analysis, light microscopy and imaging flow cytometry. Micro Fourier transform infrared spectroscopy (µ‐FT‐IR) was used to characterize the particles in each product. The mean size distribution of microplastics differed depending on the method employed and it was apparent that imaging flow cytometry was affected by high background noise that may require staining of plastics to overcome. The application of µ‐FT‐IR confirmed polyethylene as the microplastic in each product. Methodological challenges encountered in the study and the literature have highlighted the need for standardization of methods for determining microplastics.