Minisart® SRP syringe filters with a clean and chemically inert PTFE membrane. The units are ready-to-use and allow for simple, rapid and reliable ultracleaning of small volume samples for HPLC or GC analysis, which require an even more chemical resistant unit than Minisart® RC, e.g. for solvents such as acetone, dimethylformamide and DMSO, or for aggressive aqueous liquids.