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Higher strength and flexibility
Most membranes are inherently brittle and difficult to handle; it is not uncommon for filters to be damaged during loading into holders or while in use. Whatman cellulose nitrate membrane filters have a noticeably improved flexibility and are made to tolerate abuse during handling, loading and autoclaving without sacrificing integrity. These membranes are among the strongest of their type available, as measured and compared by burst pressure tests.
Low extractable levels
The level of extractables in membrane filters has become more important with advances in filtration or adsorption techniques. In particular, pharmaceutical, immunological and biomedical tissue culture and trace analysis applications can be adversely affected by high extractable levels. Whatman cellulose nitrate membrane filters have a low level of extractables, generally below that of other membranes of a similar type.
Narrow pore size distribution
One of the major features of Whatman membrane filters is the narrow distribution of pore sizes. The rated pore size of these membranes is closely controlled due to the advanced manufacturing and control system. Additionally, the batch-to-batch variation is minimized providing more consistent laboratory results.
Increased temperature stability
Membrane filters are normally autoclaved at 121°C without loss of integrity. Cellulose nitrate membranes are supplied as circles, sheets or reels.
Reduced shrinkage
Excessive shrinkage can cause problems during autoclaving and is often the cause of membranes tearing in their holders after autoclaving. It may also cause a reduction in flow rate and total throughput. Whatman membranes exhibit a low shrinkage during autoclaving.

Features and benefits
  • Narrow pore size distribution for improved surface capture and analysis
  • Low levels of extractables to ensure sample integrity

    Applications
  • Sample preparation
  • Microbiological studies
  • Filtration of aqueous solutions
    Filter types
    White plain filters
    This is the standard membrane filter for the majority of laboratory applications involving particles and cells in the range of 0.1 µm to 12.0 µm. The residue after filtration is found to be almost completely on the surface of the membrane and allows physical recovery of deposits and microscopic examination.
    Gridded filters
    Gridded filters makes it easier to count particles, microorganisms and colonies. If a gridded membrane is required please see Mixed Cellulose Ester Membranes.


 

Typical Data - Cellulose Nitrate Membranes
  Cellulose Nitrate
Thickness 105 to 140 µm
Burst strength > 2 psi
Weight 3.6 to 5.5 mg/cm2
Maximum service temperature 80ºC
Porosity 66 to 84%
Steam autoclavable Yes
Hydrophilic Yes

 

Typical Applications - Cellulose Nitrate Membranes
Field of application Pore size (µm)
General  
Microfiltration 0.1
Ultracleaning 0.1
Sterilizing 0.2
Bulk bacterial removal 0.45
Analytical precipitates 0.65
Clarifying filtration 1
Particle removal 5
Water microbiology and analysis
Bacterial colony count 0.45 (gridded) - See Mixed Cellulose Ester membranes
Sediment analysis 0.45
Suspended particles 5
Air pollution monitoring
Asbestos monitoring (NIOSH) 0.8
Food and beverage QC
E. coli and Coliforms 0.45 (gridded) - See Mixed Cellulose Ester membranes
Total bacteria count 0.2
Tissue culture
Mycoplasma removal 0.1
Sterile filtration 0.2


 

Ordering Information - Cellulose Nitrate Membranes
Catalog Number Description
0.1 μm Pore Size
7181-002 Cellulose nitrate circles, plain, 0.1 µm 25 mm 100/pk
7181-004 Cellulose nitrate circles, plain, 0.1 µm 47 mm 100/pk
10402014 Cellulose nitrate circles, plain, 0.1 µm 50 mm 100/pk
0.2 µm Pore Size
7182-001 Cellulose nitrate circles, plain, 0.2 µm 13 mm 100/pk
7182-002 Cellulose nitrate circles, plain, 0.2 µm 25 mm 100/pk
7182-004 Cellulose nitrate circles, plain, 0.2 µm 47 mm 100/pk
10401314 Cellulose nitrate circles, plain, 0.2 µm, 50 mm 100/pk
7182-009 Cellulose nitrate circles, plain, 0.2 µm 90 mm 25/pk
7182-014 Cellulose nitrate circles, plain, 0.2 µm 142 mm 25/pk
0.45 µm Pore Size
7184-001 Cellulose nitrate circles, plain, 0.45 µm 13 mm 100/pk
7184-002 Cellulose nitrate circles, plain, 0.45 µm 25 mm 100/pk
7184-003 Cellulose nitrate circles, plain, 0.45 µm 37 mm 100/pk
7184-004 Cellulose nitrate circles, plain, 0.45 µm 47 mm 100/pk
10401170 Cellulose nitrate circles, plain, sterile, 0.45 µm 47 mm 100/pk
10401114 Cellulose nitrate circles, plain, 0.45 µm, 50 mm 100/pk
7184-008 Cellulose nitrate circles, plain, 0.45 µm 82 mm 25/pk
7184-009 Cellulose nitrate circles, plain, 0.45 µm 90 mm 25/pk
10401121 Cellulose nitrate circles, plain, 0.45 µm, 100 mm 50/pk
10401126 Cellulose nitrate circles, plain, 0.45 µm, 110 mm 50/pk
7184-014 Cellulose nitrate circles, plain, 0.45 µm 142 mm 25/pk
7184-029 Cellulose nitrate circles, plain, 0.45 µm 293 mm 25/pk
0.65 µm Pore Size
7186-004 Cellulose nitrate circles, plain, 0.65 µm 47 mm 100/pk
0.8 µm Pore Size
7188-002 Cellulose nitrate circles, plain, 0.8 µm 25 mm 100/pk
7188-003 Cellulose nitrate circles, plain, 0.8 µm 37 mm 100/pk
7188-004 Cellulose nitrate circles, plain, 0.8 µm 47 mm 100/pk
7188-009 Cellulose nitrate circles, plain, 0.8 µm 90 mm 25/pk
1 µm Pore Size
7190-002 Cellulose nitrate circles, plain, 1 µm 25 mm 100/pk
7190-004 Cellulose nitrate circles, plain, 1 µm 47 mm 100/pk
7190-009 Cellulose nitrate circles, plain, 1 µm 90 mm 25/pk
1.2 µm Pore Size
7191-005 Cellulose nitrate circles, plain, 1.2 µm 50 mm 100/pk
7191-014 Cellulose nitrate circles, plain, 1.2 µm 142 mm 25/pk
3 µm Pore Size
7193-002 Cellulose nitrate circles, plain, 3 µm 25 mm 100/pk
7193-004 Cellulose nitrate circles, plain, 3 µm 47 mm 100/pk
5 µm Pore Size
7195-002 Cellulose nitrate circles, plain, 5 µm 25 mm 100/pk
7195-004 Cellulose nitrate circles, plain, 5 µm 47 mm 100/pk
10400214 Cellulose nitrate circles, plain, 5 µm, 50 mm 100/pk
7195-009 Cellulose nitrate circles, plain, 5 µm 90 mm 25/pk
8 μm Pore Size
10400106 Cellulose nitrate circles, plain, 8 µm, 25 mm 100/pk
10400109 Cellulose nitrate circles, plain, 8 µm, 37 mm 100/pk
10400112 Cellulose nitrate circles, plain, 8 µm, 47 mm 100/pk
10400114 Cellulose nitrate circles, plain, 8 µm, 50 mm 100/pk
10405079 Cellulose nitrate circles, plain, with hydrophobic rim, 8 µm 50 mm 100/pk
10400121 Cellulose nitrate circles, plain, 8 µm, 100 mm 50/pk
10400132 Cellulose nitrate circles, plain, 8 µm, 150 mm 25/pk
12 µm Pore Size
10400012 Cellulose nitrate circles, plain, 12 µm, 47 mm 100/pk
10400014 Cellulose nitrate circles, plain, 12 µm, 70 mm 100/pk

 

 

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