>Metal filters were oven-dried at 60 °C for 24 h and sediment samples were dried at 75 °C for 72 h to constant weight. 200 g of each dried sediment sample was placed in a 1 L glass beaker, and 500 mL of saturated NaCl solution (density 1.20 g cm?3) was added. The mixture was manually stirred for 2 min, and after settlement for 2 h the suspension was decanted in a 150 mL beaker.
so they wanted to get microplastics from sediment so they dried the sediment and then put the tried sediment to water with NaCl saturated solution
but why? what does NaCl do? does it make soil/sand particles stay at bottom?