Membrane Filters

A membrane is a phase that acts as a barrier to prevent mass movement but allows for the regulated passage of one or more species. The pores in a filter have maximum diameters that prevent the passage of microorganisms such as viruses or bacteria greater than a particular size. Membranes can be constructed of polymers, solvents, or non-solvents.

The membranes used in pharmaceutical processes are almost exclusively prepared by the phase-inversion technique or the “casting method,” a controlled air chamber manufacturing process.

Choose the appropriate membrane based on the porosity and retention or pore size rating. Porosity is the percentage of a filter that is comprised of pores. Retention is related to the particle size used to characterize the filter and is expressed in micrometers (μm).

Recovery is also an important factor to consider. Will the filter be able to grow captured microorganisms and provide them the proper nutrients and temperature over time? Does the filter matrix allow a free flow of nutrients? Can the cell replicate?

Our membrane filter product pages include details like material, manufacturing number, pore size, package components, and testing apparatus compatibility. Our filter membranes for microbiological analysis are sterile.