The “best membrane filter disc” is a difficult question to answer as it depends on your sample that you are filtering and the solvent is it dissolved in.
For most HPLC and Dissolution testing, hydrophilic nylon membranes are generally used because they are durable, compatible with most aqueous solvents including water and have the lowest extractables with aqueous solvents compared to most membranes. The best way to determine if nylon is compatible is to try them with your sample. You should analyze your sample (if possible) with and without filtering. There should be no change in your analysis if the filter is appropriate.
Click HERE for AQ™ filtration membrane ordering information and pictures.