0.45 micron PES hplc syringe filters-HPLC Filter. EZFlow® Syringe Filter, CA, 0.45µm, 33mm, Sterile, 100/pack. The sample prep syringe filters are used for clarification and particle removal from samples before instrumental analysis such as HPLC, IC, and GC. These Minisart® Syringe Filter, Polyethersulfone (PES), Pore Size 0.45 µm . 0.45 Micron Membrane Filter – Thomas Sci. Filter 30mm 0.45um HPLC Red.