Date: September 28, 1998 Filtration Table
An article on filters? Nah, filters are too simple. You put a small paper cone in the filter holder, add coffee, and pour on hot water. Drip, drip, drip, and the coffee's ready. That's all there is to it. But hold on a minute. There are thirty grades of Whatman standard filter paper alone, and even if we restrict ourselves to a biological laboratory, we have depth filters and screen filters; filters with different pore sizes that are tightly or loosely dispersed; packaging that employs prefilters, sheets, bags, tubes, or hollow fibers; filtration systems that use gravity, centrifugal force, vacuum, or pressure pumps; and systems that use a variety of different flow geometries (not even considering the closely related technology of binding assay membranes). Yet most people who simply use filtration as a "routine technique" in the laboratory give about as little thought to...

Interested in reading more?

Become a Member of

Receive full access to digital editions of The Scientist, as well as TS Digest, feature stories, more than 35 years of archives, and much more!
Already a member?