PVDF Syringe filter has many advantages. PVDF film has high mechanical strength, is not easy to break or curl; it has the advantages of low background, wide solvent compatibility, and excellent coloring ability; in addition, PVDF film can be tested repeatedly after proper treatment. The pore size of PVDF membrane is 0.22¦Ìm and 0.45¦Ìm. 0.22¦Ìm is suitable for proteins with molecular weight less than 20kDa, which can effectively reduce the leakage of small molecular weight proteins. Compared with 0.45¦Ìm PVDF membrane, it has higher protein adsorption rate and protein sequencing yield. For example, the adsorption capacity of insulin and BSA are 1.64 times and 1.58 times that of the commonly used 0.45¦Ìm PVDF membrane, respectively.