Cytiva Whatman™ Uniflo Syringe Filters, 0.22μm, PTFE . Cytiva Whatman™ Uniflo Syringe Filters, 0.22μm, PTFE filtration media. PTFE membrane filters are hydrophilic and autoclavable. They come in 0.22 µm and 0.45 µm pore sizes. Nylon is resistant to a range of organic solvents and suitable for use with high pH samples.