The filtration sterilization method generally uses a filter membrane. First, use a depth filter to remove large particle deposits. Then use a filter membrane for filtration. The pore size of the filter membrane is generally 0.2 μm or 0.45 μm, which can filter out most of the nutrient cells of microorganisms. The sterile syringe filter has PP, PTFE or nylon membrane. The pore size of the filter membrane is 0.2um or 0.45μm, and the pore size of the filter membrane is usually selected according to the packing size of the analytical column. Aijiren provides filter membranes with two pore sizes and different materials.