the microtcole laboratory Use of a Convenient Disposable Filter "Tip" with a Pasteur Filter Pipet for Microscale Laboratory Techniques Roberl Rothchlld me Clly University of New Yon John Jav Collese of Crlrninal Justice Depanient of science Toxicology Research and Training Cenler 445 West 59th Street New York. NY 10019
The Pasteur filter pipet, typically consisting of a Pasteur pipet with a small wad of cotton near the tip, is a convenient and essential part of microscale laboratory courses1,where it is routinely used in filtrations. If powdered decolorizing carbon is used to adsorb impurities from a hot solution duringrecrystallization, the charcoal particles may not all be retained in the filter pipet when the solution is expelled. Although this problem can be reduced by using granular or pelletized forms of decolorizing carbon, any solids that persist can be removed by using a second stage of filtration such as the disposable filter "tip" described here. This filter "tip" consists of asmall wad of cotton packed intoa short length of polyethylene tubing, -1-1.5 &I in length. with an inner diameter selected to fit snugly over the tip of the Pasteur
edited by ARDEN P. ZlPP SUNY-Cmiand Cortland, NY 13045
pipet. It is used by drawing the solution (with charcoal particles or other stray insolubles) into the usual Pasteur filter pipet, after which the filter "tip" is placed securely onto the end of the Pasteur filter pipet. The contents of the pipet are then expelled for further workup, leaving any particulates trapped between the two cotton wads. Acknowledgment The author is extremely grateful for being able to participate in.the Summer Institute in Microscale Organic Laboratory Techniques presented by the Chemistry Department at Bowdoin College, Brunswick ME, sponsored by the PEW Charitable Trust, June 1&23, 1989. This work has been supported, in part, by the U.S. Education Department Minority Science Improvement Program ( g r a n t no. G008641165), National Science Foundation Instrumentation and Laboratory Improvement Program (grant no. USE8851684), Hewlett-Packard Corp. (grant no. 0017-80769), Hoffman-La Roche, Inc., and the Sandoz Research Institute.
' Mayo. D. W.; Pike, R. M.; Butcher. S. D. Microscale Organic Laboratory, 2nd ed.; Wiley: New York, 1989; p 28.
Volume 67 Number 5 May 1990
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