cellulose nitrate filter types硝酸纤维素膜类型
白色光滑滤膜
这是大多数实验室应用的标准滤膜，用于1.0μm-5.0μm大小的颗粒和细胞。过滤后的残留物大多数保留在膜的表面，可以进行沉淀物物理性回收和显微镜观察。
用于核算和蛋白分析的硝酸纤维素膜
1975年，e．m．southern发明了从琼脂凝胶转移dna到一张硝酸纤维素膜的技术。这个技术以它的***命名为southern blotting。随后，蛋白和rna转移的技术也发展起来了。与层析技术相关的是需要相当数量的高质量的色谱纸，3mm纸已经成为全世界优选的层析纸。
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计数参数-硝酸纤维膜
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硝酸纤维
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厚度
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125um
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爆裂强度
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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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*高操作温度
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80℃
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孔率
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66-84%
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蒸汽高压**
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yes
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亲水性
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yes
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典型应用-硝酸纤维膜
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应用领域
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孔径（um）
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应用领域
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孔径（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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微过滤
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0.1
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悬浮颗粒
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5
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超净
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0.1
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空气污染监测
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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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去除大多数微生物
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0.45
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食品饮料质控
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分析性沉淀物
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0.65
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大肠菌
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0.45（网格）
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纯化过滤
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1
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总**计数
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0.2
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去除颗粒物
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5
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组织培养基
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水中微生物分析
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去除支原体
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0.1
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**计数
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0.45（网格）
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**过滤
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0.2
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订货信息-硝酸纤维膜
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尺寸（mm）
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孔径（um）
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货号
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型号1
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无菌2
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蛋白吸附力
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数量/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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强
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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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强
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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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强
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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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强
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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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强
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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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强
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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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强
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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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强
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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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