Oskar Hagelskjaer , Frederik Hagelskjær, Henar Margenat, Jeroen Sonke , Gaël Le Roux

The field of microplastic (MP) research has expanded significantly since the terminology’s inception in 2004. Despite the exponential increase in studies, the availability of environmentally relevant MP reference materials (RMs) remains limited, and no certified MP RMs exist. This study addresses the need for diverse RMs by presenting data on MP RMs of fragments (10-100 µm) and fibers (50-1000 µm), suspended in 95 vol.% ethanol solution at various concentrations. Five samples each of fragments and fibers, derived from four subsamples, were prepared and evaluated for repeatability, with relative standard deviation (RSD) determined at 10 and 9%, respectively. Novel size group-specific RSD evaluation was also conducted. The study confirms the homogeneity and distribution consistency of these RMs, demonstrating RSDs below 20% for fragments and within acceptable ranges for fibers. These RMs, branded as 'EasyMP™,' will be available for purchase, providing essential tools for accurate MP analysis and experiments, contributing to reproducible MP studies.