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Pragopor sterilized membrane ultrafilters

The ultrafilters available under the trade name Pragopor are microporous membranes made of nitrocellulose. The porous structure of the filters is created by a lamellated system of small voids which nevertheless enables separation even of the tiniest particles.

  • almost entire filtration performance
  • good chemical durability against most acids, alkalis and some solvents
  • very low weight and negligible hygroscopicity
  • negligible ash residue after burning (0,03 – 0,05 % by weight)
  • good retention capability of the filters for the particles, clogging of the pores and, consequently, the final inactivation of the filters being a very slow process
  • very smooth surface of a chalk-white colour
  • possibility of making the filters translucent and easy mineralization and dissolution of the filters in some organic solvents if required
  • possibility of a treatment of the substance retained on the filter for its examination by electron microscopy
The membrane ultrafilters are useful instruments in many fields of laboratory work, e.g.:
  • microbiology, pharmacy, hygiene and epidemiology either for cultivation of germs or for their proof and identification through microscopy
  • in virology for sterilization and determination of the germs suspensions
  • for the determination of the bacterial pollution of gases and liquids
  • for the separation of solid particles from both gases and liquids
  • for water analysis as well as many other physical and chemical instrumental methods

The sterilized ultrafilters are different form the non-sterilized types in the overall technology of manufacture and, particularly, in absence of any residual solvents which otherwise might inhibit the cultivation of some microbes.

They are available in the shape of small sectors of the diameter 35 mm and 50 mm (other sizes may be manufactured upon request) in the sorts designated by the number 4 – 9, the number being assigned to the respective pore size. After manufacture, the individual filters are packaged into the small plastic sacks, stacked into paper packets and the packets sterilized by the gamma rays.

Designation of the filterSize of the pores µmExamples of usage
Pragopor 40,85 ± 0,15Microbiology of gases, filtration of solutions, air pollution analysis
Pragopor 50,6 ± 0,1Routine microbiology of milk and dairy products, water filtration
Pragopor 60,4 ± 0,06Sterile filtration of liquids
Pragopor 70,3 ± 0,04Separation of microbes
Pragopor 80,23 ± 0,03Separation of colloid particles from solutions, observation by electron microscope
Pragopor 90,17 ± 0,03Filtration of viruses and phaguses