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APPARATUS FOR DEMONSTRATING PAPER CHROMATOGRAPHY PHILIP 5. BAKER Stable Isotope Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
A SIMPLE and convenient arrangement for demon&rating paper chromatography comprises a jar, a solid rubber stopper to fit, and an alligator clamp of the type A hole is drilled shown in the accom~anving . " - figure. part way through the stopper from the midpoint of the bottom side, and the back end of the clamp is inserted in this hole. Strips of paper of suitable length may now be placed in the jaws of the clamp while the latter, along with the stopper, is readily held and opened with one hand. This combination centers the strips with respect to the jar so that they do not stick to the sides, encloses the system tightly so that there is no evaporation from the paper strips, and assures reproducible results by standardizing the conditions. The figure shows 32-ounce, wide-mouthed bottles, 6a/a inches tall (a one-quart mayonnaise jar is good), size No. 111/2 rubber stoppers, and No. 60 Series Weller alligator clips, but of course the actual dimensions are unim~ortantas long as there is sufficient distance from the clknp to the bottom of the jar to allow satisfactory development of the chromatogram. inch of water In this particular setup, with about
in the bottom of the jar, 5-inch strips of qualitative filter paper are of an appropriate length, and such substances as inks, dye mixtures, and inorganic ions are
readily chromatographed in 10-20 minutes. A set of four bottles is convenient for comparison of a number of different substances.
