525
OCTOBER, 1953 0
SEPARATION OF RADIUM D, E, AND F BY PAPER CHROMATOGRAPHY EDGAR E. DICKEY The Institute of Paper Chemistry, Appletan, Wisconsin
THEchemical separation of radium D, E, and F is matogram, as expected, produced no visible spots for comparatively simple and is a useful exercise for students in radiochemistry. But a simpler and more convenient separation may be accomplished by paper chromatography. The chromatographic procedure was adapted from the general method of Rutter' as employed by Rao and Beri2for common sugars. The chromatograms are suitable for the preparation of radioautographs, they may he sectioned and counted, or the sections may he eluted. A solution of radium D, E, and F was prepared by dissolving one spent radon seed (in a gold capsule, furnished by the radium Service Corporation of America, Chicago, Illinois) in 0.4 ml. of aqua regia. An amount of the yellow-colored solution sufficient to produce approximately 5000 counts per minute was spotted on Whatman No. 1 filter paper (18 cm. in diameter) approximately 15 mm. from a wick a t the center of the paper. A similar spot was placed a t another point in combination with small amounts of solutions of lead and bismuth nitrates. The paper was air-dried and was placed in the irrigating apparatus, which consisted of two Petri dishes (15 mm. in height by 50 mm. in diameter, and 22 mm. in height by 150 mm. in diameter) covered with a glass plate. The smaller dish was placed inside the larger and was half-filled with nhutanol saturated with aqueous N hydrochloric acid.3 After a ~ ~ r o x i m a t e ltwo v hours, the oaDer . . was airdried and was exposed for a few minutes to moist ammonia and then t o moist hydrogen sulfide. Two brown spots appeared in t.he carrier-bearing chromatogram, one (lead) near t,he starting point and the other (bismuth) midway between the starting poiut and the prominent yellow spot of gold. The carrier-free chro-
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' RUWER,L., Analyst, 75, 37 (1950).
* RAO, P. S., A N D R. M. BERI,Pmc. Indian Acad. Sn'., 33, No. 6, Seo. A, 368-72 (1951). 8 LEDERER, M., Nature, 162, 776 (1948).
lead and bismuth. The chromatograms were sectioned with a razor blade and the pieces of paper were counted under a thin-window G-M counter. The results are shown in the figure. Thus, radium D (Ph) remained
2 Aotivit, o t Radium
1 6 8 Elansed time, days
10
12
D,E, and F Separated by P.qm Chromstography
near the starting point, radium E (Bi) moved approximately halfway down the chromatogram, and the radium F (Po) was located between the radium E and the gold. Larger scale rhromatograms were readily obtaiued with strips of paper in the conventioual type of apparatus. These chromatograms were quantitatively eluted with N hydrochloric acid by the technique of Dent.' 'DENT,C. E., Bioehem. J., 41, 240 (1947).
