Whatman* Binder-Free Glass Microfiber GF Series Filters

Grade GF/A: 1.6 �m
Offers fine particle retention 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 analysis, protein filtration and radioimmunoassay of weak beta emitters.
Grade GF/B: 1.0 �m
Three times thicker than GF/A with higher wet strength and significantly increased loading capacity. Combines fine particle retention 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.
Grade GF/C: 1.2 �m
Slightly more retentive than GF/A and 934-AH. Combines fine particle retention with good flow rate. Used for the collection of suspended solids in potable water and natural and industrial water. Fast and efficient clarification of aqueous liquids containing low to medium levels of fine particulates can be carried out in the laboratory. Used in cell harvesting and liquid scintillation counting techniques where more retentive medium loading capacity filters are required.
Grade GF/D: 2.7 �m
Considerably faster in flow rate and overall filtration speed than cellulose filter papers of similar particle retention. The filter is thick and thus 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.
Grade GF/F: 0.7 �m
This high efficiency filter will retain fine particles down to 0.7 �m. Unlike membrane filters with a comparable retention value, it has a very rapid flow rate and an extremely high loading capacity. Very effective in filtering finely precipitated proteins, GF/F can be used in conjunction with GF/D as a prefilter for the successful clarification of extremely "difficult"� biochemical solutions, fluids and nucleic acids.
Grade 934-AH: 1.5 �m
The fine particle retention of this popular grade is superior to any cellulose filter of similar speed and is capable of high retention efficiency at high flow rates. The loading capacity, like that of all glass microfiber filters, is high. It is most frequently used in water pollution monitoring techniques for suspended solids and is specified in official methods. It is also used in cell harvesting and liquid scintillation counting techniques and in air pollution monitoring.