Instead of conventional separatory funnels, this paper acts as a phase separator, separating aqueous solutions from water-immiscible solutions. Wash the paper with extra organic solvent to obtain a more quantitative separation. The organic solvent being filtered will gradually migrate to the edge of the water meniscus and will pass through the paper leaving water phase behind, if the solvent being filtered is lighter than water. If the solvent being filtered is heavier than water, the solvent will pass directly through the paper, and the water is retained. May be folded like other filter paper. Seepage occurs if the aqueous phase is left in the paper for an extended time period.