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 benefitsNarrow pore size distribution for improved surface capture and analysisLow levels of extractables to ensure sample integrity
ApplicationsSample preparationMicrobiological studiesFiltration of aqueous solutionsFilter 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 | | | 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 | | | 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 | | | 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 | | | 7186-004 | Cellulose nitrate circles, plain, 0.65 µm 47 mm 100/pk | | | 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 | | | 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 | | | 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 | | | 7193-002 | Cellulose nitrate circles, plain, 3 µm 25 mm 100/pk | | 7193-004 | Cellulose nitrate circles, plain, 3 µm 47 mm 100/pk | | | 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 | | | 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 | | | 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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