To ensure reliable experimental results and enable the highest performance from your solutions, it is essential to use the right filter. The features of a filter such as diameter, pore size, membrane material, and housing, are all important. At Ossila, we have selected a range of syringe filters which can be used for most applications and are all compatible with our solvent-safe polypropylene syringes.
|Pore Size||0.1 μm||0.22 μm||0.45 μm||1.2 μm||0.1 μm||0.45 μm||0.1 μm||0.45 μm|
|Membrane||PTFE (Hydrophobic)||PTFE (Hydrophilic)||PES|
|Filter Diameter||13 mm|
|Filtration Area||>1.3 cm2|
|Retained Fluid||<100 μl|
|Pack Size||100 filters|
|Package Type||Low dust polyethylene box|
|Filter Housing||Polypropylene / High Density Polyethylene|
|Inlet Attachment||Female Luer lock|
|Outlet Attachment||Male Luer Slip|
|Maximum Operating Temperature||60 ℃|
|Sterilization||Autoclave at 121 ℃ for 20 minutes|
Membrane Filtration Overview
Membrane filtration is a method of removing particulates from solution without the need for any heating. This filtration method is typically used in other processes, such as sublimation and distillation. It works simply by restricting the movement of particles above a specific size through a porous material. Typically membrane filtration is separated into several categories dependent upon particle size. These categories are: particle filtration, microfiltration, ultrafiltration, nanofiltraion, and reverse osmosis. These different categories cover particle sizes, ranging from centimetres down to angstroms. Below is an image highlighting the range covered by microfiltration membranes highlighting the types of materials that can be filtered out.
Membrane filtration is used in a variety of scientific fields including biotechnology, pharmaceuticals, medicine, chemistry, and semiconductor manufacturing. Each field has very different requirements for the filters and the choice of filter type can depend upon the solvent being filtered, the size of particles that need removing, whether the filters need to be sterile, the volume of solution being filtered, and the temperature of your solution. If you are unsure about what particular membrane would best suit your needs please see the following section.
Choosing the Correct Filter
At Ossila, we offer three different membrane filter materials:
- Hydrophobic PTFE (Polytetrafluoroethylene)
- Hydrophilic PTFE
- PES (Polyethersulfone).
PTFE can be used with almost any solvent due to its low reactivity and low extractables. Additionally, PTFE has extremely high thermal stability, allowing for a wider range of processing temperatures compared to standard membrane materials. However, PTFE is naturally hydrophobic, which can make the filtering of aqueous solutions difficult. To counter this, we offer the option of hydrophilic PTFE - in which the membrane surface has been treated to improve the wetting on aqueous solutions.
Due to its naturally hydrophilic nature, PES is compatible with aqueous solutions and alcohols. In fact, PES is highly recommended for the use of for filtering aqueous solutions. This is due to the reduced presence of extractables from not having to treat the membranes surface with wetting agents. In addition, due to its extremely low protein binding, PES offers superior performance for use with biological samples and culture media.
Below is a table showing the sizes of solutions suitable for different filter diameters:
We have found that 13 mm diameter filters provide the best combination of filtering capability/capacity, with minimal solution loss.
The pore size of your chosen filter depends on the material you wish to remove. As the membrane material has a pore size distribution of around an average size, it is possible that particles bigger than the stated pore size may pass through. We recommend choosing a pore size just below the minimum size of particle you wish to remove.
To the best of our knowledge the technical information provided here is accurate. However, Ossila assume no liability for the accuracy of this information. The values provided here are typical at the time of manufacture and may vary over time and from batch to batch.