V O L U M E 24, NO. 6, J U N E 1 9 5 2 dition is rarely encountered in commercial glycols, no study has been made under these conditions. LITERATURE CITED
(1) Elving, P. 3.. and Rutner, E., IND.ENG.&EM., ANAL En., 18. 1 7 6 8 (1946). (2) Hoepe, G., end Treadwell, W. D., ,yelo. chim, ~ ~ 25, t35%~ (1942).
IO55 (3) Kolthoff. I. M.. and Lingane, J. J.. "Polarography," pp. 57-8. New York, Interscience Publishere, 1941. (4) Nogaie. S. D., Norris. T. 0..and Mitchell, John.. X... ANAL. C a m . . 23, 1473-8 (1951). (5) Reinke, R. C.. and Luoe. E. N..IND.E m . C a m . , ANAL ED.,18. 244-5 (1946). (6) Warshowsky. B.. and Elving, P. J.. 1bid.. 1 8 , 2 5 3 4 (1946). (7) , Whitnsck, G. C.. and Moshier, R. W., Ibid., 16, 4 9 6 8 (1944). REOEWED for r e ~ i e wDecember 24.1951.
Awepted February 29, 1952.
Instrumental Detection of Radioactive Material on Paper Chromatograms A. RUSSELL JONES, Oak Ridge Notional hbomtory, Oak Ridge, Tenn.
HE paper chromatography of radioactive mbstances has been used for their identification and isolation. The radioactive are= of the chromatogram have been commonly detected by placing the finished chromatogram in contact with photographic film ( I ) . The presence of a radioactive tracer such as C", P', or Pal produces an image a t the corresponding area of the developed negative. Because long periods of time, up to a mouth, RE required by this procedure, a method for direot scanning and recording is urgently needed. Such a method for the recording of the position of activity on paper chromatograms bas recently been described (2). The system used consisted of a methane-type ionization chamber and a pulse-integrating counter driving a Brown recorder. .4n improvement upon this system has been developed here employing 5 novel pickup and a vibrating reed electrometer (Figure 1). By its nature the latter is an integrating circuit, since the inst,antaneous current flow across a resistor (a function of the number of ioniaing particles entering the ion chamber) is messured rather than individual counts. For this same reason, the scanning speed is limited only by t.he rate of response of the Brown recorder.
opposed and approximately 0.5 mm. apart. The paper strip was inserted brtw-een them and attached with Scotch tape to the end of the Brown chart paper. A weight attached to the other end of the strip drev it through between the ion chambers a t the same rate as the Brown chart paper advanced. This simple expedient permitted the chromatogram t o be drawn t~crossthe slits of the ion chitmbers a t a uniform rate and in exact synchronization with the chart motion.
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