Q-Max® 4 syringe filters are recommended for smaller sample sizes due to a low loss of sample inside the filter housing. Autoclavable. Available in two pore sizes (0.22 µm and 0.45 µm) and six membrane types: Cellulose Acetate (CA): Hydrophilic and low protein binding membrane. Also resistant against some alcohols. Nylon: Naturally hydrophilic with wide solvent resistance. Also suitable for aqueous samples with pH range 3-10. Binds proteins. Polyethersulphone (PES): Hydrophilic and low binding of proteins. Resists pH 1-4. PVDF: Hydrophobic membrane type. For solvent filtration. Also resistant against acids. PTFE: Hydrophobic membrane. Resistant against solvents, acids and bases. Not recommended for aqueous samples. PTFE/L: Hydrophilic membrane type. Very versatile. Can be used for water filtration as well as solvents, acids and bases.