Filtros de membrana

 

 

Mixed Cellulose Esters (MCE)

Composition: Mixed cellolose esters includes cellulose nitrate, also known as

nitrocellulose, and cellulose acetate

High porosity: Provides superior flow rates

High protein binding: can be blocked by pretreatment or utilized in applications

High purity: Triton-free and non reactive to pyrogens

Autoclavable: withstands autoclaving temperatures up to 130ºC without adversely

affecting bubble point, flow rate or microbiological recovery.

Rapid wetting time: < 3 seconds to wet a 47 mm diameter disc with aqueous 1%

methylene blue

Applications:

• standard membranes for many laboratory applications, including filter sterilizing
• 
  
•  biologocal fluids, microbiology, contamination analysis and air monitoring

• can be transparentized to view collected particles - using compatible liquid
• 
  
•  (immersion oil, toluene) or  select Opticler membranes for the "hot block"
• 
  
•  acetone vapor method

• gridded filters available for quntifying microbial growth

• available non-sterile or sterilized by ethylene oxide (ETO

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Cellulose Acetate (CA)

 Composition: mixture of cellolose triacetate and diacetate

Characteristics: low static charge and high strenght

Sterilizable: may be repeated sterilized without loss of integrity or change in bubble

point

Clean: 0.1 wt% aqueous extractables

Relative to MCE membranes:

• imporved solvent resistance to low molecular weight alcohols

• better heat resistance

• lower protein binding

Applications:

• enhanced recovery of fastidious gram positive organisms

• filtration of enzyme solutions

• diagnostic cytology

• receptor binding studies
• 
  

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Coated cellulose acetate

Composition: cellulose acetate cast onto a non-woven polyester support

Characteristics: non-fiber releasing

Low protein binding: relative to nitrocellulose

Low static charge: matrix with enhanced chemical compatiblity to low molecular

weight alcohols

Applications:

• use as a clarifying filter or prefilter

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Hydrophilic PTFE

Characteristics: maximum chemical and pH resistance

High flow rates: with minimal aqueous extractables (<0.3wt%)

Optically clear: when wet with water

Non-supported

Applications:

• ideal for HPLC and other mixtures of aqueous and organic solvents

Note: autoclaving or allowing membrane to dry will render it hydrophobic

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Hydrophobic PTFE, supported

Properties: thin, highly porous, behaves as an absolute retentive membrane

Supported: polypropylene laminated to one side to improve handling

Inert: to most chemically aggressive solvents, strong acids and bases

Thermostable: can be used up to 120ºC

Applications:

• sterilize gases: traps aqueous aerosols

• air and gas venting: allows gases to pass freely while blocking aqueous liquids,
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•  
• protect vaccum pumps and critical samples

• sterilize and clarify strong acids and many other solvents incompatible with
• 
  
• 
  
•  othermembrane types

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Hydrophobic PTFE, unsupported

Properties: thin, highly porous, behaves as an absolute retentive membrane

Inert: to most chemically aggressive solvents, strong acids and bases

Operating Temperature Range: 120-260ºC

Applications:

• sterilize gases. traps aqueous aerosols

• air and gas venting: allows gases to pass freely while blocking aqueous liquids,
• 
  
•  protect vaccum pumps and critical samples

• sterilize and clarify strong acids and many other solvents incompatible with
• 
  
•  other membranes

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Polycarbonate

Characteristics: low non-specific binding and optically translucent, extremely uniform,

cylindrical pores

Thin screen-type membranes minimize entrapment within the fikter structure,

resulting in surface capture of particles on the membrane

Stable: excellent chemical resistance, good thermal stability, non-hygroscopic and

extreme weight stable

Applications:

• Epifluorescence microscopy: available in black for this method

• Electron microscopy: smooth surface is ideal for observing captured particles

• Light microscopy: easily transparentized for optical illumination

• Beverage and sterility testing

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