Standard White Polycarbonate "Track Etch" Membrane Filters

Choose from both SPI-Pore™ and Whatman/GE™ brands

SPI Supplies offers polycarbonate membrane filters of two different types, SPI Supplies own brand of polycarbonate filters and the Whatman/GE™ brand. Click here to become familiar with some of these unique and innovative manufacturing techniques.

Typical applications include:

Microfiltering of reagents, staining fluids or water prior to critical EM preparative techniques for ultramicrotomy.
Direct observation by SEM of cells, cell organelles, fibers or contaminating particles removed from fluids.
Ideal substrates for cell growth as a cell culture plate insert. The cells do not grow "into" the membrane, they remain at all times on the surface, making them easily removable. Liquid nutrient flows easily through the pores, giving the growing cells constant access to food. And, the cells can be easily plated.

General Specifications
Extensive information for the SPI-Pore brand is available relating different pore sizes to pore density, membrane thickness, weight, bubble point and flow rates. The guarantee on the pore size is +0%, -20%. For example, 0.6ľm pore size on a membrane filter can actually have a pore size as small as .48mm but still be considered as being within the 0.6ľm product range. And a 0.6 ľm product can never have a pore size larger than 0.6 ľm. A 0.4ľm pore size product cannot ever have a pore size larger than 0.4ľm. And so on.....

Pressure specifications:
With regard to the SPI-Pore™ Membrane Filters, we guarantee they will withstand pressures of at least 2000 psi when properly supported. When a membrane filter is being used in a high pressure filter holder, claim to see use pressures well in excess of 2000 psi. If the membrane is not properly supported, expect to "burst" with as little as 15-20 psi.

Optical properties:
The SPI-Pore membranes are opaque and white after etching (the starting film is transparent) because the pores refract light. PC film itself has a crystalline structure with a dual refractive index. So the light gets bent a few times as it passes through the membrane with the pores resulting in a white - opaque appearance. This is a visual, not physical or chemical change. The membrane can become clear again with either a clearing solution or a coating that cancels the effects of the light. One can also use special microscope slides of the Cyto-Clear brand, which have a coating that essentially cancels out the white color. The pores disappear when viewed under a light microscope. Most immersion oils can serve as a clearing agent without any problems, turning the membrane from being opaque and white to clear and transparent.

Temperature limits of use:
We recommend that these membrane filters not be taken above 140 °C (284 °F).

Hydrophilic characteristics:
Polycarbonate is inherently hydrophobic and in order to increase the wetability of the membrane surface all SPI-Pore membranes are given a final treatment with PVP (polyvinylpyrrolidone). Most customers prefer PVP-treated membrane filters. However for those who believe that the PVP could interfere with their experiments, the membranes can be requested without PVP treatment as well.

It is some times asked, just how hydrophobic is the untreated membrane surface? PCTE without PVP is not truly hydrophobic like PTFE or PVDF but it is much more hydrophobic than it is hydrophilic. We are unaware of any hard data that exists in the public domain that quantitatively defines this characteristic but we have heard of contact angle measurements being made in order to get a better feel for this characteristic. PVP-Free Membrane Filters

SPI-Pore vs. Whatman/GE™ Polycarbonate Track Etch Membrane Filters
Since there is only one manufacturer in the world of the special liquid monomer from which the polycarbonate film material is made, the two brands of membrane filters are similar at the start of the process. But because different manufacturing processes are used different thicknesses of base material film are needed. For most pore sizes, the membrane thickness of the SPI-Pore membranes is thinner than the Whatman/GE™ brand. This has important implications on flow rates.

Binding of macromolecules to the membrane surface:
We are often times asked what is the affinity of nucleic acids molecule (DNA, RNA) to bind to polycarbonate membrane filter. The affinity is based strictly on the electrical charge on the PCTE membrane itself, be it SPI-Pore or Whatman/GE™. Either brand of PCTE is easily coated in order to increase affinity but other than that it is strictly based on how the DNA/RNA is affected by the intrinsic charge on the surface of the membrane.

Holding the membrane filters:
All membrane filters offered by SPI Supplies irrespective of their construction, must be used in conjunction with a specially made membrane filter holder.

Standard White Membranes

13mm (Package of 100 filters)


		SPI-Pore			Whatman/GE™
Pore Diameter µm	nm	SPI #	Each	In Stock	SPI #	Each	In Stock
0.01	10	E00153-MB	$112.48	Yes
0.03	30	E0033-MB	112.48	Yes
0.05	50	E0053-MB	112.48	Yes
0.08	80	E0083-MB	112.48	Yes	F0083-MB	126.50	Yes
0.1	100	E0113-MB	86.52	Yes	F0113-MB	105.50	Yes
0.22	220	E0213-MB	54.08	Yes	F0213-MB	71.55	Yes
0.4	400	E0413-MB	54.08	Yes	F0413-MB	71.55	No
0.65	650	E0613-MB	61.65	Yes
0.8	800	E0813-MB	61.65	Yes	F0813-MB	73.53	Yes
1.0	1000	E1013-MB	61.65	Yes	F1013-MB	73.53	Yes
2.0	2000	E2013-MB	61.65	No
3.0	3000	E3013-MB	61.65	Yes	F3013-MB	80.25	Yes
5.0	5000	E5013-MB	61.65	Yes	F5013-MB	76.69	Yes
8.0	8000	E8013-MB	61.65	No	F8013-MB	73.53	No
10.0	10,000				F10013-MB	104.29	Yes
12.0	12,000	E12013-MB	61.65	No
14.0	14,000	E14013-MB	61.65	Yes
20.0	20,000	E20013-MB	61.65	Yes

25mm (Package of 100 filters)

		SPI-Pore			Whatman/GE™
Pore Diameter µm	nm	SPI #	Each	In Stock	SPI #	Each	In Stock
0.01	10	E00155-MB	$126.54	Yes
0.03	30	E0035-MB	124.37	Yes	F0035-MB	160.08	Yes
0.05	50	E0055-MB	117.88	Yes	F0055-MB	137.04	Yes
0.08	80	E0085-MB	117.88	Yes	F0085-MB	142.33	Yes
0.1	100	E0125-MB	98.42	Yes	F0125-MB	137.04	Yes
0.2	200	E0225-MB	61.65	Yes	F0225-MB	82.46	Yes
0.4	400	E0425-MB	61.65	Yes	F0425-MB	82.46	Yes
0.6	600	E0625-MB	72.46	Yes	F0625-MB	82.46	Yes
0.8	800	E0825-MB	72.46	Yes	F0825-MB	88.39	Yes
1.0	1000	E1025-MB	72.46	Yes	F1025-MB	84.29	Yes
2.0	2000	E2025-MB	72.46	Yes	F2025-MB	88.39	Yes
3.0	3000	E3025-MB	72.46	Yes	F3025-MB	92.03	Yes
5.0	5000	E5025-MB	72.46	Yes	F5025-MB	92.03	Yes
8.0	8000	E8025-MB	72.46	Yes	F8025-MB	92.03	Yes
10.0	10000	E10025-MB	72.46	No	F10025-MB	84.29	Yes
12.0	12000	E12025-MB	72.46	Yes	F12025-MB	88.39	Yes
14.0	14000	E14025-MB	72.46	Yes
20.0	20000	E20025-MB	72.46	Yes

47mm (Package of 100 filters)

		SPI-Pore			Whatman/GE™
Pore Diameter µm	nm	SPI #	Each	In Stock	SPI #	Each	In Stock
0.01	10	E00157-MB	$203.32	Yes	F00157-MB	329.85	Yes
0.03	30	E0037-MB	203.32	No
0.05	50	E0057-MB	203.32	Yes	F0057-MB	257.38	Yes
0.08	80	E0087-MB	203.32	No	F0087-MB	257.38	Yes
0.1	100	E0147-MB	150.33	Yes	F0147-MB	238.90	Yes
0.2	200	E0247-MB	118.00	Yes	F0247-MB	143.10	Yes
0.4	400	E0447-MB	118.00	Yes	F0447-MB	143.10	Yes
0.6	600	E0647-MB	118.00	Yes	F0647-MB	143.10	Yes
0.8	800	E0847-MB	118.00	Yes	F0847-MB	143.10	Yes
1.0	1000	E1047-MB	118.00	Yes	F1047-MB	143.10	Yes
2.0	2000	E2047-MB	118.00	Yes	F2047-MB	143.10	Yes
3.0	3000	E3047-MB	118.00	Yes	F3047-MB	143.10	Yes
5.0	5000	E5047-MB	118.00	Yes	F5047-MB	143.10	Yes
8.0	8000	E8047-MB	118.00	Yes	F8047-MB	143.10	Yes
10.0	10000	E10047-MB	118.00	Yes	F10047-MB	143.10	Yes
12.0	12000	E12047-MB *	118.00	Yes	F12047-MB	143.10	Yes
14.0	14000	E14047-MB	118.00	No
20.0	20000	E20047-MB	118.00	Yes

* While supplies last

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