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Membrane ultrafilters Pragopor

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 Pragopor membrane ultrafilters are manufactured in the shape of small sectors of the diameter 24 – 150 mm (most often 35 mm and 50 mm) or as square-shaped foils of the size 0,5 x 0,5 m in the particular sorts designated by number 1 – 11, the number being assigned to the respective pore size:
Designation of the filterSize of the pores µmExamples of usage
Pragopor 14,0 ± 1,0Prefiltration cytology
Pragopor 22,5 ± 0,5Radioactive aerosols
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
Pragopor 100,12 ± 0,02Filtration of high-molecular proteins
Pragopor 110,05 ± 0,01Ultrafiltration of proteins