What are Syringe Filters?

Syringe filters are useful when removing particles from liquid samples before going through an analysis to prevent damages to the apparatus like chromatography. Compared to others they are cheaper and you can buy PES syringe filters online to handle your small volume liquid filtration. When it comes to functionality, they are easier to handle and eliminates the difficulty you get from Buckner filters. You should take note however that the solid portion of the sample cannot reclaim unless the filter is removable.

You can also use syringe filters for gases and bacteria removal for samples. 

Filter Choices

There are factors that contribute to a choice of a syringe filter.

Here are some of the top ones:

1. The Size of the Pores

The pore sizes vary from one filter to another. The most used ones are 0.45 um and 0.2 um. The 0.45 is used more because they suit many procedures. When the particles are much smaller the 0.2 um pore size is more preferred. When the particles are smaller than a 0.1 um pore size is not effective then it is time to consider other filters like centrifugal filters.

2. The Material Used for the Filter

There are a variety of materials used to make syringe filters. The common ones include polyamide (PA), cellulose acetate (CA) and polyethersulfone (PES). They are differently compatible with certain liquids and gases which require you to make the careful choice of your application. They are also effective in different ways.

• Surfactant-free: Have high flowing rates, low absorption together with a thermal stability. It is mostly used in cytology, binding studies, and general filtration.

• Polyethersulfone: These have excellent flowing speeds and can handle large volumes of solutions with low protein absorption. They work well in biological, environmental and pharmaceutical applications.

• Hydrophobic: They are not wetted with humidity, compatible with a lot of chemicals and hydrophobic permanently. They work well in filtration of gases and sterilize strong solvents or acids.

• Polyamide: These are very resistant to alkaline chemical solutions and are used for removing particles for analytical purposes

3. The Size of the Filter

To easily know the hold-up volume you need to look at the diameter of the filter. When filtration is ongoing the solid particles close the pores on the filter reducing the parts of the filter that can be used and then eventually blocking it completely. Liquids that are loaded with particles fill up the filters faster than the lighter/clear ones. 

When you increase the diameter of the filter you are making provision for particulate-laden liquids to be filtered. Whenever the pressure required to push the liquid through the filters increases then that shows that the pores are filling up and you need to replace the filter. An increase in diameter of a filter signifies an increase in the hold-up volume. If you try too hard by increasing the pressure the filter will damage pouring the particles into the already filtered liquid.

If you buy PES syringe filters you experience better flow rates and you will handle aqueous solutions with success.

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