Laboratory Filtration Selection Guide Selecting a Filter Filtration Guide Membrane Materials Terms
- Determine the particle size to be retained or filtered. Membranes will retain all particles equal to, and then larger than their designated pore size.
- Assess the chemical compatibility of the membrane filter with the liquid or gas to be filtered. Consider the chemical resistance properties of the all parts that will contact the filtrate.
- Depending on the procedure performed, the membrane color or surface pattern may be important.
- Also consider hydrophilic or hydrophobic membranes; temperature, flow rate, throughput, and sterilization needs.
Use this general guide to determine the optimal type of filtration for your particle sizes. Each type of filtration is designed to separate differing ranges of microparticles and particles: - ultrafiltration is best with particles of roughly 10,000-1,000,000 MW; microfiltration is best with particle sizes of roughly 0.1-10 µm;
- macrofiltration is best with particle sizes greater than 50 µm.
| Type of filtration | Ultrafiltration | Microfiltration | Macrofiltration | | Units | Dalton (MW) | Microns (Ωm) | 50 Ωm or greater,
visible to the human eye | Particle examples
and sizes | Trypsin (24,000)
Serum alburmin (67,000)
Gamma globulin (169,000)
Viruses (600,000 to 30,000)
Endotoxins (500,000 to 12,000) | Mycoplasm (0.08 to 0.4)
proteins (0.0005 to 0.5)
Fungi (0.7 to 3)
Yeast (0.6 to 4)
Bacteria (0.3 to 12) | Spores
Pollen
human hair
Sands | |
Disclaimer: Cole-Parmer products are not approved or intended for, and should not be used for medical, clinical, surgical or other patient-oriented applications.
