Hydrophobic filter cartridges are characterized by permanently hydrophobic PTFE membrane, specially designed for filtration of aggressive solvents, acid and base samples. They are also ideal for sterile venting of air or other gases. They can provide low protein binding, low extractables, high throughputs, broad chemical compatibility and the highest process security. Due to their hydrophobic characteristic, they must be pre-wetted with ethanol or IPA before the filtration of aqueous solutions.