The minispike outlet, available on 13 mm PTFE, Nylon, GH Polypro and PVDF Acrodisc ® syringe filters, allows for easy dispensing into autosampler vials. Membrane Design Membrane Type (PTFE, GHP, PVDF, Nylon) — Typically, the first step in selecting a suitable filter is to choose a membrane that is chemically compatible with the sample (see