PTFE HPLC Syringe Filter

2023-02-06

Polytetrafluoroethylene (PTFE) membranes are resistant to almost all solvents, acids and alkalis, with high mechanical strength, high-temperature liquids, and very low levels of extractable. It can filter corrosive organic solvents, strong alkalis and hot solutions, and is ideal for needle-type filter materials.

Three steps to tell you how to choose the right syringe filter:

First Step:

Select the diameter of the syringe filter according to the volume of the filtered sample: for a sample volume less than or equal to 10mL, select a filter with a diameter of 13mm; for a sample volume less than or equal to 100mL, select a filter with a diameter of 25mm; for a sample volume less than or equal to 150mL, select a filter with a diameter of 30mm/33mm.

Second Step:

Select the pore size of the filter according to the nature of the filtered sample: if the particle size of the column packing is less than or equal to 3μm, select the filter with pore size 0.22μm; if the particle size of the column packing is greater than 3μm, select the filter with pore size 0.45μm.

Third Step:

The filter membrane is selected according to the characteristics of the filter sample: mainly hydrophilic PTFE and hydrophobic PTFE. Hydrophilic PTFE is obtained by modifying the conventional hydrophobic PTFE, which is also suitable for filtering aqueous and organic solutions and is more convenient and chemically resistant. Compounds that do not contain hydrophilic groups are hydrophobic, but after modification, they contain hydrophilic groups, such as -0H, -COOH, and so on. In layman’s terms, after modification, water becomes easily attracted, making it easy to penetrate the membrane and achieve the effect of filtration. Before the modification, there is a great resistance or tension, and there is a repulsive effect so that it is not easy to filter.

Hydrophilic PTFE: both aqueous and organic materials can pass through;

Hydrophobic PTFE: can only pass organic matter;