Approximately 50 mg of the MP powders were dispersed in 1.5 mL of absolute ethanol and vortexed for 1 min to disrupt any particle agglomeration. 100 µL micropipette tips were cut at the end to create a wider opening (∼ 2.5 mm) to allow the passage of larger MPs. The tips were then rinsed with absolute ethanol (EtOH) to remove any MPs that may be generated during the cutting. The use of plastic materials, such as the pipette tips, should be avoided in all MP research, however, due to the large quantities of the MP powders produced and analyzed in this work, we consider them to produce only statistically insignificant numbers of new MPs. Glass slides were cleaned by compressed air and set-down at a tilted angle (10 °) from the surface. The MP suspension was agitated using the micropipette with the widened tips before 25 µL of the suspension was collected and deposited at once on the raised end of the glass slide. The droplet would then extend down the slide, dispersing the MPs as it extended before drying. The resulting dispersion had the faster-sedimenting, larger MPs concentrated on the raised end of slide, with smaller MPs concentrated on the lowered end.