Craig Tube Hint

Craig Fryhle (fryhle@u.washington.edu)
Mon, 6 Oct 1997 09:59:44 -0700 (PDT)

Dr. Waldow has suggested a solution to the problem of Craig tubes with
Teflon inserts that don't drain properly when they are centrifuged. He
has found that gently scoring the rounded part of the Teflon insert with
your fingernail in about three places provides just enough of a passage
for the solvent to drain into the lower portion of the tube during
centrifugation. Apparently the Teflon "flows" over time and use to match
exactly the fit in the glass part of the Craig tube, thus preventing the
liquid from draining down during centrifugation. The scoring procedure is
a work-around that can be applied when needed.

Thanks to DAW for the suggestion.

CBF

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Craig B. Fryhle, Ph.D. Office 206-535-8314 FAX 206-536-5055
Associate Professor Email fryhle@u.washington.edu
Department of Chemistry URL http://rainier.chem.plu.edu/fryhle.html
Pacific Lutheran University
Tacoma, Washington 98447 ^ ^ ^ ^ ^ ^
^ ^^^ ^^^^^^^ ^ ^^^ ^^^^ ^^^ ^
^^^^^^^^^ ^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^