Millex 33 mm sample preparation syringe filters feature Express PLUS polyethersulfone (PES) membrane. Used for general particulate filtration prior to liquid chromatography (HPLC) or other instrument analysis, the filters remove fine particles to protect chromatography columns from premature plugging. The low-protein binding membrane provides rapid flow rates and high throughput for the sterilization and clarification of 10 ml to 200 ml of aqueous and mild organic solutions. Large surface area provides fast flow rates. Both 0.22 μm and 0.45 μm pore sizes are available. Millipore Corp. 800-645-5476 www.millipore.com/generalfiltration