In many biological, biopharmaceutical, and laboratory procedures, preparation of samples is a critical stage. It requires accuracy by complete elimination of microorganisms and particles. In this regard, using syringe membrane filters can largely help in ensuring accurate and consistent experimental results. It is a wheel-shaped filter having a plastic body. Its membrane is made for effective purification of different contaminants. They are predominantly used in pharmaceutical industry. When looking to buy them, there are certain prerequisites that you should remember. Here, they are:

Selection of the Right Membrane:

The membrane selection should be based on the chemical compatibility of the membrane with the sample liquids. Here, you should also check the protein binding capacity of the membrane. The main types of membranes available in a syringe filter are PTFE, PES, PVDF, MCE, Nylon, and Polypropylene. Each of these filters has specific properties for particular applications. You should select the membrane according to the nature of a sample to be purified.

PTFE Syringe Filters

For instance, PES filters are ideal for tissue culture filtration and nylon filters are preferred for purification of aqueous substances. The protein-based samples can be filtered using PVDF filters having low protein binding capacity and MCE or Mixed Cellulose Ester membranes are fit for sensitive biological solvents. When you need hydrophobic membranes for non-polar solvents, you can rely on PTFE filters because they have a chemical resistant polymer that can remove contaminants from highly corrosive substances as well.

Selection of Right Pore Size:

It is a major factor defining the right selection of a syringe filter. You should choose the perfect pore size depending on the size of particles to be filtered. The pore size is generally represented in terms of Microns. Hence, for purification of bacteria with a diameter of 0.3 microns, use the membrane having a pore size of 0.3 microns. The porosity of a filter should be selected according to the size of potential particulates in the sample. Here, you should understand that fine porosity means that higher pressure is required for passing the sample through the filter. For larger volumes of particulate matter, you should prefer glass fiber filter with your membrane filter.

Selection of Filter Diameter:

The filter inlets have female Leur compatibility and inert housings. They are available in four main classifications of diameter, viz.

  • 30mm filters for large sample volumes and higher filtration speed. They have holdup volume less than 50 µl.
  • 25mm filters for high throughput. Their hold up volume is less than 50 µl
  • 13mm filters for a wide range of applications with holdup volume less than 10 µl.
  • 4mm filters for smaller samples with hold up volume less than 7 µl. The membrane and housing of these filters are compatible with both organic and aqueous solutions.

When buying the filters, you also need to consider the types of filters. They are available as hydrophobic or hydrophilic membranes and as sterile or non-sterile filters. This selection depends on the requirements of specific applications. Prefer buying them from a trusted manufacturer providing them in proper packaging with color coding for easy identification.