Performing a syringe filtration step prior to chromatographic injection helps to ensure more consistent and reliable results, and helps to protect delicate instruments and prolong column life. Choice PES Syringe Filters 0.2 µm, 25 mm, 100 Pk. Choice PES Syringe Filters 0.45 µm, 25 mm, 100 Pk. Choice PES Syringe Filters 0.2 µm, 13 mm, 100 Pk.