SDLABIO Syringe Filter

First, according to the properties of the sample (such as water phase, organic solvent or acid and alkali), select the appropriate filter membrane material (such as nylon, PVDF, PTFE) and pore size (commonly used 0.22 um syringe filter or 0.45 micron syringe filter​), and confirm the sealing and sterilization status of the package (if aseptic operation is required).

After extracting the liquid to be filtered with a sterile syringe filter, connect the needle filter tightly to the front end of the syringe through the Luer connector, and pay attention to the direction of the filter membrane (usually marked “↑” to indicate the flow direction). If a hydrophobic membrane (such as PTFE) is used, it is necessary to pre-wet it with a compatible solvent (such as ethanol) to improve the filtration efficiency.

Then slowly and evenly push the syringe piston to allow the liquid to pass through the filter membrane to avoid excessive pressure causing the filter membrane to rupture; if there is a sudden increase in resistance, stop the operation and check whether it is blocked. After the filtration is completed, collect the filtrate directly for analysis (such as HPLC injection or microbial detection).

Discarded filters are classified and treated as biological or chemical waste, and those containing biohazards need to be sterilized by high pressure. Attention should be paid to chemical compatibility (such as nylon is not resistant to strong acids), sterile operating environment (clean bench) and the front and back of the filter membrane throughout the process to ensure filtration efficiency and sample cleanliness. This process is suitable for the rapid purification of small volume (1-50mL) samples and is both flexible and convenient.