The material of the syringe filter should be compatible with the chemical nature of the sample to avoid extractables or sample contamination. Common materials used in syringe filters include PP (polypropylene), nylon, PES (Polyethersulfone), PTFE (polytetrafluoroethylene), PVDF (Polyvinylidene fluoride), etc. Here is a guideline of the difference between these types of syringe filters.
| Material | Features | Applications | pH Range |
| Nylon Syringe Filter | Low extractable Compatible with both aqueous and organic solutions | Ideal for neutral pH aqueous solutions and mixed solvents. Commonly used for clarification or particle removal prior to HPLC analysis | 5-12 |
| PES Syringe Filter | Highest flow rate and low protein binding | Used for filtration of aqueous, mild organic solutions and tissue culture media. | 1-14 |
| Hydrophilic PVDF Syringe Filter | Lowest protein binding | Compatible with protein solutions and mild organic solutions. | 2-10 |
| Hydrophilic PTFE Syringe Filter | Maximum chemical resistance, strong acid and alkali resistance. No need to pre-wet before use. | Filtration of both aqueous and organic solutions. Sample filtration before UHPLC, HPLC, and LC-MS. | 1-14 |
| Hydrophobic PTFE Syringe Filter | Highest chemical compatibility. Aqueous samples are compatible if proper pre-wetting (commonly use alcohol or isopropanol) Can handle high-temperature liquids. | Used for venting and gas filtration. Prevent moisture passing through air vents. Used for organic solutions, it boasts exceptional performance when handling highly corrosive samples, strong acidic solvents, and alkaline solvents. | 1-14 |
| MCE Syringe Filter | High flow rate and high throughput. High-protein binding. Excellent biocompatibility. | Used for clarification of aqueous solutions and general laboratory filtration. Capable of being used with water-based solutions, hydrocarbons, and a variety of other organic solvents. | 3-10 |
| CA Syringe Filter | Extra low non-specific binding. High recovery. | Used for aqueous samples containing proteins, or similar large organic molecules biomolecule solution. | 4-8 |
| PP Syringe Filter | High rentention efficiency. High dirt holding capacity. | Use for pre-filtration, clarification filtration, fine particle removal. | 1-14 |
Choose the Right Pore Size
Choose a syringe filter with a pore size smaller than the size of the particles you want to filter out of your solution. To illustrate, if you wish to eliminate particles larger than 0.2 microns in diameter, opt for a syringe filter featuring a pore size of 0.2 μm.
Syringe filters are available in a variety of pore sizes: 0.1 μm, 0.22 μm, 0.45 μm, 0.8 μm, 1.0 μm, 1.2 μm, 5.0 μm, 10.0 μm etc. Among them, 0.22 μm and 0.45 μm are the most commonly used ones.
Solution filtration
0.1 μm syringe filters are used for mycoplasma filtration.
0.22 μm syringe filters are commonly used for sterile filtration (bacteria removal).
0.45 μm and above are used for clarification and prefiltration.
Gas filtration
0.2 μm syringe filters are commonly used for air/gas sterile filtration.
Choose the Right Diameter
The size of the syringe filter should be compatible with the volume of the sample you want to filter.
- For samples ranging from 1-10ml, it is recommended to use a 13mm syringe filter with a hold-up volume of less than 25μl.
- For samples ranging from 5-100ml, it is recommended to use a 25mm syringe filter with a hold-up volume of less than 100μl.
- For samples ranging from 10-200ml, it is recommended to use a 33mm syringe filter with a hold-up volume of less than 125μl.
Sterility
Sterile Packed
For sterilized required solutions, an individually packed sterile syringe filter is needed to ensure optimal performance without contamination.
Non-sterile Packed
If the solution is going to be filtered again, then a non-sterile syringe filter could meet the requirements. Non-sterile syringe filters are widely used for sample preparation applications, such as for sample preparation in analytical chemistry, protecting analytical equipment from particle contamination.
Autoclavable Syringe Filter
Cobetter autoclavable syringe filters can be autoclaved at 121ºC (130ºC max) for 30 minutes for max 20 times.
