Membrane Selection Guide by Application

Typical Applications	Type of Membrane	Benefits and References
Air Analysis
Particulate analysis	PCTE or PETE	Samples are collected in one plane, in focus. Superior morphologic resolution. No clearing of membrane for most applications. Simpler slide preparation. Uniform sample deposition. Particles can be fractionated by discrete sizes
Bromine and Chlorine	Silver (0.45µm)	NIOSH 6011
Polyaromatic hydrocarbons	Silver	Reusable
Silica (crystalline), zinc oxide, cotton dust, chromic acid mist, oil mist, lead sulfide, nuisance dust, carbon black	PVC (0.8 and 5.0µm) Silver (0.45 µm)	Silica and contaminant free NIOSH Methods 5000, 7505, 0500, 0600, 7601, 7502, 7500, 7602.
Cadmium, cyanides, lead, quartz in coal dust, welding and brazing fumes	MCE (0.8 µm)	NIOSH Methods 7048, 7904, 7082, 7602, 7200
Trace elements, for aerosols	PCTE or PETE (0.2 – 8.0 µm)	Low trace elements contamination in special aerosol membranes
Quartz/Silica	Silver	NIOSH Methods S315, OML.
Zinc oxide fumes	Silver	NIOSH Method S316.

Analytical Methods
Activation analysis	PCTE or PETE	Minimal absorption of beta radiation Low membrane trace elements.
Adsorbable organic halide (AOX)	PCTE (0.4 µm)	Low trace halides in membrane.
Densitometry	PCTE or PETE	Uniform transmissivity of light within same lot.
Emission spectroscopy	PCTE or PETE	Very low trace element background.
Gravimetric analysis	PCTE or PETE	More accurate weight measurements. Matched weight filters not required. Tare weight not significantly affected by sample adsorption. Low, constant tare and ash weights. Non-hygroscopic. Tare weight not significantly changed by moisture adsorption. Reduced analysis time .
Microchemical analysis	PCTE or PETE	Microchemical tests can be made on the membrane. Excellent chemical resistance.
Qualitative analysis	PCTE	Surface capture of sample in one plane. Low trace elements in membrane.
Radioactive monitoring and analysis	PCTE or PETE	Accurate, consistent measurements of low energy alpha and beta emissions from sample. Corrections for filter absorption eliminated. Best for fractionating radiocolloids.
X-ray diffraction	Silver	Minimum of interfering spectra. NIOSH Method 7500, 7501, 9000
X-ray fluorescence	PCTE or PETE	Membrane can be used for the target. Low trace elements-no characteristics radiation. Ideal for combined SEM/X-ray fluorescence analysis.

Blood Analysis / Filtration
Plasmapheresis	PCTE or PETE (0.6 or 0.8 µm)	Low hemolysis due to smooth membrane surface. Low non-specific binding of proteins.
Red blood cell deformability	PCTE (4-7 µm)	Thinness and capillary pores of membrane allow near in-vivo measurements without hemolysis.
Red blood cell filtration	PCTE (8.0 µm)	Low hemolysis due to smooth membrane surface.
Cell / Tissue Culture
Studies of cells, Cell culture	PCTE or PETE (0.4 – 5.0 µm)	Near in-vivo conditions High diffusion rate.
Prefiltration of tissue culture media	Glass fiber filter, syringe filters	High dirt loading capacity Low cost.
Sterile filtration of tissue culture media	MCE, Nylon or syringe filters (0.1 and 0.22 µm)	Absolute removal of microorganisms. Excellent throughput.
Chemotaxis
Chemotaxis	PCTE	Rapid cell migration. Reduced incubation times. Sterilization not necessary
Cytology
Cytology	PCTE (3.0, 5.0, 8.0 µm)	All cells are in focus. Membrane does not stain. Resistant to alcohols, stains and xylene. No cell loss, cellular distortion, nor cell lysing. No RBCs, proteins, or cellular debris in specimen. High strength allows less critical handling. Simpler microscopic analysis. High flow rates minimize cell damage.
General Filtration
Prefiltration and coarse clarification	Glass fiber filter	High dirt loading capacity. Low cost.
Beverage stabilization	MCE or Nylon (0.45 – 1.2 µm)	Absolute filtration.
Particulate and bacterial removal	PCTE, MCE, Nylon (0.1 – 5.0 µm)	Absolute removal.
Finish clarification	MCE or Nylon (0.22 – 1.0 µm)	High dirt loading capacity. Absolute filtration.
Fuel testing	MCE (0.45, 0.8 µm)	ASTM D2276
Liposome extrusion	PCTE (0.03 – 0.4 µm)	Consistency of vesicles. Faster than other methods.
Sterilizing filtration	PCTE, MCE, Nylon(0.1 – 0.22 µm)	Absolute removal of bacteria.
Serum filtration	MCE or Nylon (0.1 and 0.22 µm)	Absolute removal of microorganisms. Relatively high dirt loading capacity.
Forensic
Gunshot residue test (GSR)	PETE (0.4 and 0.6 µm)	Surface capture in one plane. Excellent chemical resistance.
Microscopic examination of samples	PCTE or PETE (0.4 µm)	Surface capture in one plane of focus.
HPLC Solutions Filtration
HPLC solutions filtration	PETE, PTFE or syringe filters (0.4 µm)	Excellent chemical resistance. High flow rates.
Microorganism Studies and Analysis
Concentration	PCTE or PETE (3.0 – 5.0 µm)	Low non-specific binding of microorganisms
Fractionation	PCTE or PETE	Low non-specific binding of microorganisms
Cryptosporidium	PCTE	Surface capture.
Giardia lamblia	PCTE (5.0 µm )	Low background clutter.
Harvesting	PCTE or PETE	Surface capture of microorganisms. Ability to backwash for harvesting.
Observation	PCTE or PETE (0.2 – 0.8 µm)	Surface capture of microorganisms. Membrane is non-staining.
Direct Total Microbial Count	PCTE (0.2 – 5.0 µm)	See Epifluorescent Microscopy under MICROSCOPY.
Dirofilaria immitis	PCTE (5.0 µm)	Surface capture of microfilaria. Membrane does not stain.
Legionella	PCTE (0.2 µm)	Low non-specific binding
Shistosoma haematobium	PCTE (12.0 - 14.0 µm)	Surface capture.
Sterility testing	MCE (0.22 and 0.45 µm)	21 CFR436
Total and fecal coliform	MCE (0.45 and 0.7 µm)	Standard Methods/Water and Waste water, 17 ^thEd.
Yeasts and molds	PCTE (black), (0.6 and 0.8 µm)	Surface capture of sample. Membrane does not stain.
Microscopy
Direct optical observation	PCTE or PETE (0.2 and 0.4 µm)	Samples are collected in one plane, in focus. Superior morphologic resolution. Excellent chemical compatibility. Membrane does not stain. No clearing of membrane necessary. Simpler slide preparation. Uniform sample deposition. Minimum autofluorescence. Standard Methods/Water and Waste Water, 17 ^thEdition. ASTM D4455-85, D4454-85, and F1095-88.
Electron microscopy	PCTE (0.1 – 5.0 µm)
Epifluorescent microscopy Bacteria total count and observation. Yeast total count and observation. Spore observation	Black PCTE 0.2 – 5.0 µm 0.6 and 0.8 µm 5.0 µm
Nucleic Auto Studies
Alkaline elution	PCTE (0.8 – 2.0 µm)	Does not absorb DNA. DNA is retained intact.
Filtration of DNA fragments	PCTE (0.2 µm)	Single strand passes through filter without breaking.
Pharmaceuticals
Small volumes	Syringe filters	Convenient.
Prefiltration	Glass fiber filter	Inexpensive and high dirt loading capacity.
Sterilization	MCE, Nylon (0.1 – 0.22 µm)	Absolute retention. 21 CFR 210 and 211.
Virus or Protein
Concentration / separation / fractionation / purification	PCTE or PETE (0.01 – 0.1 µm)	Low non-specific binding of viruses and proteins.
Observation	PCTE or PETE (0.01 and 0.03 µm)	Direct observation of viruses by epifluorescent microscopy.
Water Analysis / Filtration (See also Microorganism Studies and Analysis)
Organic halides (AOX) Low Chlorine	PCTE (0.4 µm)	Undetectable halides from membrane in residual ash.
Nitrates, nitrites phosphates and ammonia, Low extractable	PCTE (0.4 µm)	Does not leach out chemicals of interest from membrane.
Culturing of microorganisms	MCE (0.2 – 0.8 µm)	Standard Methods/Water and Waste Water, 17 ^thEdition.
Direct count of microorganisms	Black PCTE (0.4 – 5.0 µm)	See Epifluorescent Microscopy under MICROSCOPY.