HPLC sample filters in syringe filter format; Solvent filters in membrane disc format The minispike outlet, available on 13 mm PTFE, Nylon, GH Polypro, Acrodisc® Syringe Filters - Pall Corporation. GHP: GH Polypro membrane (GHP, hydrophilic polypropylene) Female Luer-Lok♢ inlet/male luer outlet or minispike outlet as noted.