hydrophilic ptfe membrane filter 0.22 um for healthcare 0.22 um PTFE filter | Sigma-Aldrich This 33 mm syringe filter with a Hydrophilic Polyethersulfone membrane, for non-sterile filtration on the Samplicity G2 system, has a 0.22 µm pore size used in preparation of aqueous solutions prior to chromatography or other instrument analyses.