Why it is important to analyze the chemical composition of microplastics in environmental samples.

Research on microplastics is not straightforward, and, until recently, the visual methods used to identify microplastics might have overestimated their amounts, mainly when the target plastics were <500 μm. The analytical approach has moved on since then, and more sophisticated methods are now used to sample and extract microplastic particles from a very wide variety of environmental samples. Therefore, as spectroscopy is the most reliable way to identify microplastics with sufficient certainty, reviewers demand the assignment of polymer types to single microplastic particles in environmental and biological samples, as a condition of final manuscript acceptance. This is a legitimate requirement for three fundamental reasons. First, it is important to confirm the correct nomenclature-which is a scientific principle applicable beyond microplastics pollution research. Second, plastics research is important, primarily due to the intrinsic characteristics of plastic constituent polymers, such as persistence in the environment, which often does not apply to other anthropogenic particles. Third, current scientific discussion on microplastic contamination issues is centered on their relatively long persistence in the environment, and only if reliable methods are used to identify plastic particles will the microplastic research field improve its credibility, survive the test of time, and become a permanent research field.