Cellulose Nitrate Filter Types硝酸纖維素膜類型
白色光滑濾膜
這是大多數(shù)實驗室應用的標準濾膜，用于1.0μm-5.0μm大小的顆粒和細胞。過濾后的殘留物大多數(shù)保留在膜的表面，可以進行沉淀物物理性回收和顯微鏡觀察。
用于核算和蛋白分析的硝酸纖維素膜
1975年，E．M．Southern發(fā)明了從瓊脂凝膠轉移DNA到一張硝酸纖維素膜的技術。這個技術以它的***命名為Southern Blotting。隨后，蛋白和RNA轉移的技術也發(fā)展起來了。與層析技術相關的是需要相當數(shù)量的高質量的色譜紙，3MM紙已經(jīng)成為全世界優(yōu)選的層析紙。
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計數(shù)參數(shù)-硝酸纖維膜
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硝酸纖維
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厚度
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125um
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爆裂強度
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>2 psi
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重量
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3.6-5.5 mg/cm2
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*高操作溫度
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80℃
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孔率
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66-84%
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蒸汽高壓**
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yes
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親水性
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yes
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典型應用-硝酸纖維膜
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應用領域
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孔徑（um）
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應用領域
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孔徑（um）
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普通
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沉淀物分析
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0.45
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微過濾
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0.1
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懸浮顆粒
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5
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超凈
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0.1
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空氣污染監(jiān)測
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**
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0.2
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Asbestons Monitoring(NIOSH)
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0.8
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去除大多數(shù)微生物
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0.45
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食品飲料質控
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分析性沉淀物
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0.65
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大腸菌
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0.45（網(wǎng)格）
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純化過濾
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1
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總**計數(shù)
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0.2
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去除顆粒物
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5
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組織培養(yǎng)基
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水中微生物分析
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去除支原體
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0.1
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**計數(shù)
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0.45（網(wǎng)格）
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**過濾
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0.2
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訂貨信息-硝酸纖維膜
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尺寸（mm）
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孔徑（um）
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貨號
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型號1
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無菌2
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蛋白吸附力
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數(shù)量/包
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WCN
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25
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0.2
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7182-002
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平滑
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否
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強
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100
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25
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0.1
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7181-002
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平滑
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否
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強
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100
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25
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0.45
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7184-002
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平滑
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否
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強
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100
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25
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0.65
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7186-002
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平滑
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否
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強
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100
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25
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0.8
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7188-002
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平滑
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否
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強
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100
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25
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1.0
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7190-002
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平滑
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否
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強
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100
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25
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3.0
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7193-002
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平滑
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否
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強
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100
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25
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5.0
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7195-002
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平滑
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否
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強
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100
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Recommended for the majority of routine applications, this membrane is manufactured under strictly controlled conditions. The user will benefit from the performance improvements which are now available in Whatman membrane filters, including very narrow pore size distribution and low levels of extractables.
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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.
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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
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Narrow pore size distribution for improved surface capture and analysis
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Low levels of extractables to ensure sample integrity
Applications
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Sample preparation
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Microbiological studies
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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.
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Typical Data - Cellulose Nitrate Membranes
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Cellulose Nitrate
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Thickness
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105 to 140 μm
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Burst strength
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> 2 psi
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Weight
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3.6 to 5.5 mg/cm2
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Maximum service temperature
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80oC
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Porosity
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66 to 84%
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Steam autoclavable
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Yes
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Hydrophilic
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Yes
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Typical Applications - Cellulose Nitrate Membranes
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Field of application
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Pore size (μm)
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General
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Microfiltration
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0.1
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Ultracleaning
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0.1
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Sterilizing
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0.2
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Bulk bacterial removal
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0.45
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Analytical precipitates
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0.65
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Clarifying filtration
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1
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Particle removal
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5
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Water microbiology and analysis
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Bacterial colony count
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0.45 (gridded) - See Mixed Cellulose Ester membranes
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Sediment analysis
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0.45
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Suspended particles
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5
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Air pollution monitoring
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Asbestos monitoring (NIOSH)
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0.8
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Food and beverage QC
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E. coli and Coliforms
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0.45 (gridded) - See Mixed Cellulose Ester membranes
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Total bacteria count
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0.2
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Tissue culture
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Mycoplasma removal
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0.1
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Sterile filtration
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0.2
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