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These membranes are characterized by a smoother and more uniform surface than pure nitrocellulose filters. Also, the color contrast provided by the filter surface facilitates particle detection and minimizes eye fatigue. The ME range has a lower cellulose acetate content compared to the WME range of membranes.
Eased counting process
In microbiological colony counting procedures, the color contrast between the surface and the colonies facilitates the counting process.
Plain or gridded
Many microbiological techniques include colony counting after incubation as the standard method of quantification. Whatman gridded filters have clearly defined grid lines spaced at 3.1 mm or 5 mm intervals. The special ink used is nontoxic and completely free from bacterial growth inhibitors.
Whatman black mixed cellulose esters are available plain for automatic colony counting applications, as well as gridded to assist in manual counting procedures. Black membranes provide contrast between residue or cell colors and the filter without having to counter-stain the membrane.
Sterile filters
For those laboratories preferring to use membranes sterilized by autoclaving for microbiological work, Whatman provides black gridded membranes in packs with pads ready for laboratory autoclaving.
Features and benefits
  • Sterile options available for critical applications
  • Excellent contrast for easier particle detection
  • Grids are nontoxic and do not inhibit bacterial growth, ensuring sample integrity
  • Black plain and black gridded membranes have a mix of cellulose nitrate and cellulose acetate
  • The membrane offers a high degree of internal surface area for greater adsorption of product
  • Higher dirt loading capacity
  • Biologically inert with good thermal stability
  • No surfactants to contaminate samples
  • Uniform microporous structure of membrane gives high flow rates
  • Thermally stable
Applications
The membrane is particularly effective in applications requiring higher flow rates and larger volume filtration including clarification or sterilization of aqueous solutions, particulate analysis and removal, air monitoring and microbial analysis. Other applications include:
  • Clarification or sterilization of aqueous solutions
  • Cytology
  • Air monitoring
  • HPLC samples (aqueous)
  • Virus concentration
  • Particulate analysis
  • Biological assays
  • Food microbiology including enumeration of E. coli in foods
  • Bacteriological studies
  • Particle counting from liquids and aerosols
  • Yeasts and molds


 

Typical Data - Mixed Cellulose Ester Membranes

Burst strength > 10 psi
Weight 4.3 to 5.0 mg/cm2
Maximum service temperature 130°C
Porosity 74 to 77%
Steam autoclavable Yes
Solvent resistancy Medium
Protein binding Medium


 

Product Selection - Mixed Cellulose Ester Membranes

Pore size (µm)
(membrane type)
Thickness
(µm)
Water flow rate
Δp = 0.9 bar
(s/100 ml/12.5 cm2)
Air flow rate
Δp = 3 mbar
(s/100 ml)
Bubble point
(bar)
WME product range 140 - - -
ME product range
0.2 (ME 24) 135 20 - 3.7
0.45 (ME 25) 145 12.5 - 2.8
0.6 (ME 26) 135 4.8 21 1.9
0.8 (ME 27) 140 2.8 11.6 1.3
1.2 (ME 28) 140 2 9.3 0.8
3 (ME 29) 150 1.2 6.7 0.7


 

Ordering Information - Mixed Cellulose Ester Membranes

Catalog Number Description
Mixed Cellulose Ester (WME Range) - Plain
0.45 µm Pore Size
7140-104 Mixed cellulose ester circles (WME), 0.45 µm, 47 mm, 100/pk
Mixed Cellulose Ester (ME Range) - Plain
0.2 µm Pore Size (ME 24)
10401706 Mixed cellulose ester circles (ME 24), 0.2 µm, 25 mm, 100/pk
10401712 Mixed cellulose ester circles (ME 24), 0.2 µm, 47 mm, 100/pk
10401770 Mixed cellulose ester circles (ME 24), sterile, 0.2 µm, 47 mm, 100/pk
10401714 Mixed cellulose ester circles (ME 24), 0.2 µm, 50 mm, 100/pk
10401772 Mixed cellulose ester circles (ME 24), sterile, 0.2 µm, 50 mm, 100/pk
10401721 Mixed cellulose ester circles (ME 24), 0.2 µm, 100 mm, 50/pk
10401726 Mixed cellulose ester circles (ME 24), 0.2 µm, 110 mm, 50/pk
10401731 Mixed cellulose ester circles (ME 24), 0.2 µm, 142 mm, 25/pk
0.45 µm Pore Size (ME 25)
10401606 Mixed cellulose ester circles (ME 25), 0.45 µm, 25 mm, 100/pk
10401612 Mixed cellulose ester circles (ME 25), 0.45 µm, 47 mm, 100/pk
10401670 Mixed cellulose ester circles (ME 25), sterile, 0.45 µm, 47 mm, 100/pk
10401614 Mixed cellulose ester circles (ME 25), 0.45 µm, 50 mm, 100/pk
10401662 Mixed cellulose ester circles (ME 25), without interleaving paper, 0.45 µm, 50 mm, 100/pk
10401672 Mixed cellulose ester circles (ME 25), sterile, 0.45 µm, 50 mm, 100/pk
10401618 Mixed cellulose ester circles (ME 25), 0.45 µm, 90 mm, 50/pk
10401621 Mixed cellulose ester circles (ME 25), 0.45 µm, 100 mm, 50/pk
10401626 Mixed cellulose ester circles (ME 25), 0.45 µm, 110 mm, 50/pk
10401631 Mixed cellulose ester circles (ME 25), 0.45 µm, 142 mm, 25/pk
0.6 µm Pore Size (ME 26)
10401506 Mixed cellulose ester circles (ME 26), 0.6 µm, 25 mm, 100/pk
10401512 Mixed cellulose ester circles (ME 26), 0.6 µm, 47 mm, 100/pk
10401514 Mixed cellulose ester circles (ME 26), 0.6 µm, 50 mm, 100/pk
10401521 Mixed cellulose ester circles (ME 26), 0.6 µm, 100 mm, 50/pk
0.8 µm Pore Size (ME 27)
10400906 Mixed cellulose ester circles (ME 27), 0.8 µm, 25 mm, 100/pk
10400909 Mixed cellulose ester circles (ME 27), 0.8 µm, 37 mm, 100/pk
10400912 Mixed cellulose ester circles (ME 27), 0.8 µm, 47 mm, 100/pk
10400970 Mixed cellulose ester circles (ME 27), sterile, 0.8 µm, 47 mm, 100/pk
10400914 Mixed cellulose ester circles (ME 27), 0.8 µm, 50 mm, 100/pk
10400921 Mixed cellulose ester circles (ME 27), 0.8 µm, 100 mm, 50/pk
1.2 µm Pore Size (ME 28)
10400806 Mixed cellulose ester circles (ME 28), 1.2 µm, 25 mm, 100/pk
10400812 Mixed cellulose ester circles (ME 28), 1.2 µm, 47 mm, 100/pk
10400814 Mixed cellulose ester circles (ME 28), 1.2 µm, 50 mm, 100/pk
10400821 Mixed cellulose ester circles (ME 28), 1.2 µm, 100 mm, 50/pk
3 µm Pore Size (ME 29)
10400706 Mixed cellulose ester circles (ME 28), 3 µm, 25 mm, 100/pk
10400712 Mixed cellulose ester circles (ME 28), 3 µm, 47 mm, 100/pk
10400714 Mixed cellulose ester circles (ME 28), 3 µm, 50 mm, 100/pk
10400772 Mixed cellulose ester circles (ME 28), sterile, 3 µm, 50 mm, 100/pk
Mixed Cellulose Ester Membranes (ME Range) - Gridded
0.2 µm Pore Size (ME24)
10406970 Mixed cellulose ester circles (ME 24), white/black grid 3.1 mm, sterile 0.2 µm, 47 mm, 100/pk
10406914 Mixed cellulose ester circles (ME 24), white/black grid 3.1 mm, 0.2 µm, 50 mm, 100/pk
10406972 Mixed cellulose ester circles (ME 24), white/black grid 3.1 mm, sterile, 0.2 µm, 50 mm, 100/pk
0.45 µm Pore Size (ME 25)
10406812 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, 0.45 µm, 47 mm, 100/pk
10407970 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, sterile, 0.45 µm, 47 mm, 100/pk
10406871 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, sterile, 0.45 µm, 47 mm, 1000/pk
10406512 Mixed cellulose ester circles (ME 25), white/black grid 5 mm, 0.45 µm, 47 mm, 100/pk
10409712 Mixed cellulose ester circles (ME 25), black/white grid 3.1 mm, 0.45 µm, 47 mm, 100/pk
10409770 Mixed cellulose ester circles (ME 25), black/white grid 3.1 mm, sterile, 0.45 µm, 47 mm, 100/pk
10409771 Mixed cellulose ester circles (ME 25), black/white grid 3.1 mm, sterile, 0.45 µm, 47 mm, 1000/pk
10409414 Mixed cellulose ester circles (ME 25), green/black grid 3.1 mm, 0.45 µm, 47 mm, 1000/pk
10406814 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, 0.45 µm, 50 mm, 100/pk
10406862 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, without interleaving paper, 0.45 µm, 50 mm, 100/pk
10406873 Mixed cellulose ester circles (ME 25), white/black grid 3.1 mm, sterile, 0.45 µm, 50 mm, 1000/pk
10406514 Mixed cellulose ester circles (ME 25), white/black grid 5 mm, 0.45 µm, 50 mm, 100/pk
10406572 Mixed cellulose ester circles (ME 25), white/black grid 5 mm, sterile, 0.45 µm, 50 mm, 100/pk
10406562 Mixed cellulose ester circles (ME 25), white/black grid 5 mm, without interleaving paper, 0.45 µm, 50 mm, 100/pk
10409714 Mixed cellulose ester circles (ME 25), black/white grid 3.1 mm, 0.45 µm, 50 mm, 100/pk
10409772 Mixed cellulose ester circles (ME 25), black/white grid 3.1 mm, sterile, 0.45 µm, 50 mm, 100/pk
10409462 Mixed cellulose ester circles (ME 25), green/black grid 3.1 mm, without interleaving paper, Sterile, 0.45 µm, 50 mm, 100/pk
0.6 µm Pore Size (ME 26)
10409814 Mixed cellulose ester circles (ME 26), black/white grid 3.1 mm, 0.6 µm, 50 mm, 100/pk
0.8 µm Pore Size (ME 27)
10408970 Mixed cellulose ester circles (ME 27) white/black grid 3.1mm, sterile, 0.8 µm, 47 mm, 100/pk
10409970 Mixed cellulose ester circles (ME 27), white/black grid 3.1 mm with pad, sterile, 0.8 µm, 47 mm, 100/pk
Mixed Cellulose Ester Membranes (WME Range) - Gridded
0.2 µm Pore Size
7187-114 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, 0.2 µm, 47 mm, 100/pk
0.45 µm Pore Size
7141-002 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, 0.45 µm, 25 mm, 100/pk
7141-004 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, 0.45 µm, 47 mm, 100/pk
7141-104 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, sterile, 0.45 µm, 47 mm, 100/pk
7141-114 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, sterile, without pad, 0.45 µm, 47 mm, 100/pk
7141-124 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, sterile, 0.45 µm, 47 mm , 200/pk
7141-154 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, sterile, without pad, 0.45 µm, 47 mm, 1000/pk
7141-204 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, autoclave pack, sterile, 0.45 µm, 47 mm, 100/pk
7153-004 Mixed cellulose ester circles (WME), black/white grid 3.1 mm, 0.45 µm, 47 mm, 100/pk
7153-104 Mixed cellulose ester circles (WME), black/white grid 3.1 mm, sterile, 0.45 µm, 47 mm, 100/pk
7155-004 Mixed cellulose ester circles (WME), green/black grid 3.1 mm, sterile, 0.45 µm, 47 mm, 100/pk
0.8 µm Pore Size
7148-002 Mixed cellulose ester circles (WME), white/black grid 3.1 mm, 0.8 µm, 25 mm, 100/pk

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