Glass Microfiber Filter Paper

Photo of Whatman 934-AH Glass Microfibre Filters

Whatman 934-AH. The fine particle retention (1.5 µm) and flow rate (13.0 mL/sec) of this popular grade is superior for its high retention efficiency at high flow rates and its high loading capacity. This filter is a smooth surface, high retention borosilicate glass microfiber which withstands temperatures over 500°C. Specified in Standard Methods 2540D for determining total suspended solids in water, removal of turbidity and filtration of bacterial cultures. Grade 934-AH is used for a wide range of laboratory applications.

Photo of Whatman GMF 150 Multilayer Glass Microfiber Prefilter

Whatman has developed a new filter medium by combining two microfiber filters in one. Manufactured from 100% borosilicate glass microfibres, the filter is binder free and unique in its construction: a course layer on top of, and meshed with, a fine layer. This filtration technique allows for higher particle loading capacity, faster flow rate and and life extendance of the filter. Multiple porosities means greater filtration efficiency. The Multigrade GMF 150 represents the new dimension in separation science leading to faster and more cost effective filtration.

Photo of Whatman Grade GF/A Glass Microfiber Filters

Whatman GF/A glass microfibre filters offer fine particle retention (1.6 µm) and high flow rate, as well as good loading capacity. Used for high efficiency general purpose laboratory filtration, including water pollution monitoring of effluents, for filtration of water, algae and bacteria cultures, foodstuff analyses, protein filtration and radioimmunoassay of weak ß emitters. Recommended for gravimetric determination of airborne particulates, stack sampling and absorption methods of air pollution monitoring. 100 circles/box.

Photo of Whatman Grade GF/B Glass Microfiber Filters

Whatman Grade GF/B is three times thicker than GF/A with higher wet strength and significantly increased loading capacity. Combines fine particle retention (1.0 µm) with good flow rate. Particularly useful where liquid clarification or solids quantification is required for heavily loaded fine particulate suspensions. Can be used as a finely retentive membrane prefilter. Used in LSC techniques where high loading capacity is required.

Photo of Ahlstrom 161 Medium Speed Glass Microfiber Filter Paper
Ahlstrom 161, 1.1µm - Medium Speed. This popular grade offers finer particle retention and higher flow rate than traditional analytical filter papers. Used in general laboratory applications, cell harvesting, liquid scintillation counting, and in the monitoring of air and water pollution. Generally recommended for water pollution monitoring techniques for total suspended solids method 209.
Photo of Ahlstrom 151 Slow Speed Glass Microfiber Filter Paper

Ahlstrom 151, 0.7µm - Slow Speed is a high performance grade designed to retain extremely fine particles down to 0.7 µm. Has retention comparable to membrane filters while providing higher flow and loading capacity. Recommended for filtering fine precipitated proteins. In the filtration of nucleic acids and difficult biochemical solutions, Ahlstrom 151 is used in combination with Ahlstrom 141 as a highly efficient protective and retentive pre-filter to extend the loading capacity of membrane filters.

Photo of Ahlstrom 141 Fast Speed Glass Microfiber Filter Paper
Ahlstrom 141, 3.1µm - Fast Speed offers better filtration speed and a higher loading capacity than an analytical filter paper of similar particle retention. Particularly recommended for pre-filtration of membrane filters and is also used in combination with Ahlstrom 121 as a highly efficient protective and retentive grade density pre-filter for membrane filters.
Photo of Ahlstrom 131 Medium Speed Glass Microfiber Filter Paper
Ahlstrom 131, 1.0µm - Medium Speed is the standard grade found in many environmental applications offers slightly more retention than Ahlstrom 111 with slightly lower filtration speed and loading capacity. Recommended for the collection of suspended solids in potable water and in industrial wastes. In biochemical tests, suited for cell harvesting, liquid scintillation counting and the analysis of carbohydrates.
Photo of Whatman Grade GF/C Glass Microfibre Filters

Whatman No. GF/C combines fine particle retention (1.2 µm) with good flow rate. The standard filter in many parts of the world for the collection of suspended solids in potable water and natural and industrial wastes. Fast and efficient clarification of aqueous liquids containing low to medium levels of fine particulates. Widely used for cell harvesting, liquid scintillation counting and binding assays where more loading capacity is required.

Photo of Ahlstrom 121 Medium Speed Glass Microfiber Filter Paper
Grade 121 is a very thick grade that offers finer particle retention than Ahlstrom 111 with high wet-strength and loading capacity. Recommended for the clarification of liquid suspensions loaded with fine particulates. Also used in membrane pre-filtration and is also found in quantification of solids, and LSC (Liquid Scintillation Counting) techniques that require high loading capacity.
Photo of Ahlstrom 111 Fast Speed Glass Microfiber Filter Paper
Ahlstrom 111: 1.2µm - Fast Speed. This grade offers fine particle retention with high filtration speed and good loading capacity. Used in general laboratory filtration including atmospheric and water pollution monitoring such as intake controls, ozone-level, and water effluents. Grade 111 is also well suited for filtration of water and protein, testing of algae, bacteria cultures and for radioimmunoassay with weak beta emitters. Also recommended for filtering solvents in a high-resolution laboratory.
Photo of GF/F Glass Microfiber Filters. Whatman
Whatman No. GF/F is a high efficiency filter that will retain fine particles down to 0.7µm. Unlike membrane filters with a comparable retention value, it has a very rapid flow rate and an extremely high loading capacity. Suitable for critical applications including enumeration of Salmonella and Pseudomonas Aeroginosa, clarification of protein solutions and filtering samples and solvents prior to HPLC.
Photo of GF/D Glass Microfiber Filters. Whatman
Whatman No. GF/D is considerably faster in flow rate and overall filtration speed than cellulose filter papers of similar particle retention (2.7 µm). The filter is thick and consequently exhibits a high loading capacity. Designed as a membrane prefilter and available in sizes to fit most holders. GF/D will provide good protection for finely retentive membranes. Can be used in combination with GF/B to provide very efficient graded prefilter protection for membranes.