The properties of syringe filters made from different materials are extremely verifying. Therefore, the choice of the filter especially depends on the chemicals used for synthesis.
The following table provides an overview of the most common materials for syringe filters combined with the acronyms, the application areas as well as the chemical resistance of each synthetic.
|Specific Properties||Application Areas|
|Cellulose Acetate (CA)||Low protein absorbtion, especially suited for steril filtration and clarification of aqueous solutions, culture media, buffers and serums. Good chemical resistance versus alcoholics and oils with a pH range from 4 to 8. This hydrophilic membrane is characterized by excellent flow trough and extraordinary temperature stability up to 180° C.|
|Cellulose Nitrate (CN)||Cellulose nitrate membranes are standard membranes for analytical and microbiological membrane filtration. These filters are available in many different pore sizes to cover various application areas like water, food or drink analysis. Chemical resistance versus aqueous solutions with a pH from 4 to 8, carbon hydrates or organic solvents is guaranteed up 130° C.|
|Polyamide (PA)||Hydrophilic membranes that can be used several times for filtration of aqueous or organic solvents and aqueous solutions with a pH ranging from 3 to 14. Especially suited for steril filtration and clarification due to low amount of extractables.|
|Polycarbonate (PC)||Membranes made from polycarbonate are characterized by a uniform, round pore structure for the whole membrane. Particles can be identified easily due to the high contrast to the smooth surface.|
|Polytetrafluoroethylene (PTFE)||Permanently hydrophobic filter material, perfectly applicable for air and gas as well as non-polar liquids. PTFE membranes are characterized by an extraordinary chemical resistance versus nearly all chemicals and are suited for both filtration of acids or aggressive solvents and particle filtration of air or water samples up to 200° C.|
|Regenerated Cellulose (RC)||Regenerated cellulose membranes are solvent resistent and hydrophilic. 0.45 µm pore sizes are mainly used for HPLC sample preparation. This membrane type is resistent versus most solvents, as well as aqueous solutions with a pH from 3 to 12 and temperature stable up to 200° C.|
The filter size especially depends on the filtration volume. For small volumes (< 1 ml) syringe filters with a diameter of 3 mm are usually, for medium volumes (1-10 ml) 15 mm and for large volumes (> 10 ml) 25 mm. Common pore sizes for UHPLC and HPLC columns with small particle sizes (< 3 µm) are 0.2 and for columns with larger particle sizes (> 3.5 µm) 0.45 µm, respectively. The pore sizes available range from sub µm up to 10 µm.
The following tables give an overview about the different filter types and the specific lables of each producer.
|CA||Puradisc CA||Minisart NML|
|GF||Whatman GD/X||Minisart GF||Acrodisc GF|
|PA||Puradisc PA||Minisart NY||Acrodisc PA||Millex|
|PES||Puradisc PES||Minisart PES||Acrodisc PES||Millipore Express|
|PTFE||Puradisc PTFE||Minisart SRP||Acrodisc PTFE||Millipore LCR|
|PVDF||Puradisc PVDF||Acrodisc PVDF||Durapore|
|RC||Whatman Spartan||Minisart RC|