Filtration Membrane Discs

Choose 0.22 µm for sterilizing filtration of aqueous samples and 0.45 µm for clarification or particulate removal. Match pore size to organism/particle retention targets and required flow rate. Merck, Sartorius, and Whatman offer consistent pore-size control across common diameters such as 47 mm and 25 mm.

Select by chemical compatibility and binding: PVDF is often low protein-binding for biological samples; nylon suits broad aqueous filtration and high flow; MCE and cellulose nitrate are widely used for general microbiology and analytical filtration. Compare Merck, Sartorius, Thermo Scientific, and Whatman options to standardise results.

Use the diameter that fits your holder or funnel assembly. 25 mm discs are compact and conserve sample volume; 47 mm discs are a common standard for routine lab filtration and water testing. Check your hardware spec and then choose a matching disc from Merck, Sartorius, Whatman, Fisherbrand, or Thermo Scientific.

For sterile workflows, use sterile, individually packed membranes or sterile packs and handle with clean forceps. Avoid touching the filtration area and keep holders clean between runs. Sartorius, Merck, and Whatman sterile membranes help reduce contamination risk, while consistent technique ensures reliable microbiology results.

Flow can drop when pore size is too small for the load, the sample contains high particulates, or the membrane has strong binding to sample components. Pre-filtering, selecting 0.45 µm for clarification, or switching material (e.g., nylon vs PVDF) can help. Review Merck, Sartorius, and Whatman specifications for flow and throughput.