This phase separating paper is impregnated with stabilised silicon, thus rendering it hydrophobic and it retains water, but allows solvents to flow through. The flow stops automatically when the entire solvent has passed through, this eliminates the need to use separating funnels.

Used for filtration of organic solvents that have been contaminated with water to separate the aqueous from the organic phase, filtration of extracting solvents in clinical or medical labs and separation of emulsions that are formed during the extraction of aqueous plant or drug solutions.