Membrane Filters

Photo of Membrane Filters, Whatman WTP (PTFE)
One of the major applications for the PTFE (Type WTP) filter is the clarification of corrosives, solvents and aggressive fluids. This includes the important requirement in HPLC analysis for sample filtration where any solid particles can cause permanent damage to the column. The 0.5µm pore size is normally used. Air and gas sterilization make use of the hydrophobic characteristics of PTFE membranes and their ability to stop aqueous aerosols. Usual pore sizes are 0.2µm and 0.5µm.
OE67 0.45µm cellulose acetate membrane filters exhibit very low protein binding capacity. They are hydrophilic making them suitable for aqueous and alcoholic media. The cellulose acetate membranes have improved solvent resistance, particularly to low molecular weight alcohols and increased heat resistance. With high physical strength, the membrane filters can be used up to 180°C; suitable for hot gases and can be sterilized by all methods without sacrificing the integrity of the membrane.
Photo of Nylon Membranes. Whatman WNYL
Whatman nylon membranes are available in pore sizes ranging from 0.1µm to 0.45µm and in diameters from 13mm to 142mm. These membranes are ideally suited to many applications. In the biotech area, they are used to filter tissue culture media, microbiological media, buffers and solutions. For chromatography applications, they are used to filter samples, aqueous and organic mobile phases and can also be used for vacuum degassing. Nylon membranes are intrinsically hydrophilic, eliminating the need for wetting agents that could possibly be extracted when filtering aqueous solutions.
Photo of Anopore® Inorganic Membranes. Whatman
The Anopore® Anodisc inorganic membrane is ideal for a wide range of laboratory filtration applications. This unique material has a precise, non-deformable honeycomb pore structure with no lateral crossovers between individual pores. Filters at precisely the stated cutoff, allowing no larger sized particles to pass through the membrane. The Anopore® inorganic membrane is composed of a high purity alumina matrix that is manufactured electrochemically. The membrane also exhibits low protein binding, has minimal autofluorescence, is non-toxic and supports cellular growth.
Photo of Cyclopore Polycarbonate Membrane Filters. Whatman
These membranes are available in pore sizes ranging from 0.1µm to 12 µm. Hydrophilic as standard, Cyclopore polycarbonate membranes can also be made hydrophobic upon request. They feature a zero level of non-specific protein binding. The high selectivity of Cyclopore polycarbonate membranes allows precise particle separation and fractionation. Additionally, the smooth and flat surface provides an excellent support for all applications requiring detailed observation of collected samples. Cyclopore's patented membrane technology leaves surfaces perfectly flat and smooth.
Photo of Mixed Ester Membrane Filters. Whatman
Whatman black and green mixed ester membranes are composed of cellulose acetate (20%) and cellulose nitrate (80%). 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. Compared to pure nitrocellulose filters, mixed ester membranes have a smoother and more uniform surface as well as offer color contrasting, making it easier to detect particles.
Photo of Sterile Cellulose Nitrate Membrane Filters, Gridded. Whatman
Whatman WCN cellulose nitrate membrane filters pre-sterilized in gridded style. This grade is manufactured under strictly controlled cleanroom conditions. These sterile filter papers are primarily used in microbiological laboratory applications. Cellulose nitrate membrane filters are the standard filter for the majority of laboratory applications involving particles and cells in the range of 0.11µm to 5.0µm. These sterile filters are supplied individually packed, with or without an absorbent pad included, in sealed polyester envelopes.
Photo of Membrane Filters, Cellulose Nitrate. Whatman
Whatman Type WCN (cellulose nitrate), white, plain. The standard membrane filter for the majority of laboratory applications involving particles in the 0.1-5.0 µm. size range. Suitable for all aqueous based gravimetric and clarification techniques.