As well all know, syringe filters are for many areas, such as ambient air, waste gas, water quality analysis, drug testing, medical research, life science research, etc. But do you know how to use it to achieve filtration well? Here are some steps:

Some steps to achieve filtration using a syringe filter:

glass fiber syringe filter sterile Hydrophilic PTFE Syringe Filter

Syringe filter filtration process:

  • Before inhaling the sample, draw some air into the syringe. This minimizes liquid retention.
  • Invert the syringe and wipe off any residue from the tip.
  • Connect the syringe to filter syringes using the connector. Tighten lightly for a secure seal.
  • Filter the solution in the syringe and pour it into the sample bottle.
  • Then, remove the filter, draw air into the syringe, reinstall the filter, and press the plunger to filter out the residual sample. This allows for sample recovery.
  • If the filtration speed suddenly becomes fast or too slow during use, it means should replace a new membrane if  damaged membrane, and should repeat the experiment.
  • Use caution with syringes with volumes of less than 10 mL, because it is easy to generate enough pressure to burst the filter. And it is not recommended to be reused.
  • The volume of fluid remaining in the filter after use is another factor in selecting filter size. Low residual volume filters are recommended when handling costly or extremely precious fluids. Reduces residual volume while ensuring efficient filtration of samples.

Some questions about using syringe filters:

1. Does the bottled water syringe filter used in the laboratory need to be sterilized by moist heat?

  • No need: each Hawach syringe filter, such as syringe filter 0.22 micron ptfe , is a plastic-sealed inlet filter that sterilizes relatively cleanly.
  • Need: if the bottle was opened during ultraviolet sterilization, it seems that ultraviolet rays cannot penetrate ordinary glass, but the ozone generated by ultraviolet lamps is the real source of sterilization. The ozone cannot enter without opening the bottle.
  • There are many possible causes of bacterial contamination, especially considering whether the ultra-clean workbench needs to replace the filter screen, or it is brought in by the experimental operation. Of course, it could also be a filter issue.
  • In addition, polyethersulfone has a glass transition temperature of 225°C, and the heat resistance between polysulfone and polyarylsulfone, should be autoclavable.

2. Does the dead volume of the syringe filter refer to the maximum volume of a water sample that can be filtered?

  • Dead volume generally reflects the volume loss of the sample.
  • When the sample is filtered, part of the sample will always remain in the filter or membrane, affecting the recovery rate of the final sample.
  • The smaller the dead volume, the smaller the loss and the higher the recovery
  • Dead volume is the volume that cannot be recovered

3. Sterile Syringe Filters Produced Instructions:

  • Sterile filters, including gas filters or liquid filters, should test for integrity before and after use in accordance with the integrity testing procedures for sterile filters.
  • After s complete the integrity test, the filter membranes and filters are for aseptic production and sterilized.
  • Sterilization methods are divided into steam sterilization and ethylene oxide gas sterilization.
  • A common method is steam sterilization.
  • When steam sterilized the sterilization filter online, the pressure difference between the front and rear of the filter should be monitored during sterilization.
  • Record the temperature and pressure during the sterilization process, as well as the sterilization time.
  • A sterilizing filter cannot be for more than 1 working day.
  • It cannot filter different products at the same time, but it can be used to filter multiple batches of the same product and should carry integrity testing out.