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