4562 - GHP Membrane - Acrodisc Syringe Filters, 25mm, Pall . Product description. "These syringe filters offer a choice of filter media: hydrophobic PTFE membrane for exceptional chemical and temperature compatibility -hydrophilic nylon membrane for excellent chemical compatibility with esters, bases, and alcohols, without prewetting -GHP (hydrophilic polypropylene) membrane for low protein