INDUSTRIAL AND ENGINEERING CHEMISTRY
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with dilute sulfuric acid and precipitate the halides with a solution of silver sulfate. Excessive quantities of sodium sulfate are then removed by dehydration with ethyl alcohol and filtration. The boron after removal of the alcohol is concentrated by solution and filtration or distillation with methyl alcohol. The use of phosphorus pentoxide is very effective in inducing esterification, particularly in the distillation of residues which require much water to transfer. The final solution of boron is made with methyl alcohol containing 5 per cent (by volume) of sulfuric acid. Usually 5 readings on 3 portions of the final solution are made and the average is taken as the actual boron content. Theformula p.p.ni. = R X Vo/W converts the scale reading to p. p. m. of boron in the moisture-free sample.
SPECTROSCOPIC ANALYSESFOR BORON TABLEI. COMPARATIVE IS PLANT MATERIAL Sample Carrot (leaves) Carrot (tuber) Sweet potato Tomato (fruit) Tomato (fruit Tomato (fruit) Tomato (vines) Tomato (vines) Cabbage Lettuce
VOL. 9, KO. 6
Storage of Carbon Dioxide from Dry Ice for Dumas Determinations W. H. HAMILL AND J. A. ALICINO Fordham University, New York, N. Y.
D
RY ICE is a conveaient source of pure carbon dioxide and the following method of storage makes it readily available for Dumas nitrogen determinations with less effort and in purer form than is ordinarily possible with double Kipp generators.
Boron Permanganate Polariaation method method P. p . m. P. p. m. 7.4 5 2 9 a
1 75 0 5
10.1
5 3 5 5 8.0 1s 0
The equipment and procedure described have been in use for about 6 months. Analyses compare very favorably with values obtained by the previously published method ( 7 ) . Individual readings are much closer to the average, smaller samples are permissible, and the analytical procedure is much shorter. Data on a few samples of plant material analyzed by both methods are given in Table I. Summary
Polarizing attachments and an oxygen-methane blast burner for the spectroscopic determination of boron are described. Natural gas saturated with methyl borate in methyl alcohol is ignited in an oxygen blast to excite the spectrum. A standard solution on ignition and polarization produces a reference spectrum in juxtaposition to the spectrum of the sample. The degrees of rotation of the analyzing plate are read on a scale in terms of parts per million of boron in the solution upon matching the intensities of the spectra. Recommendations are given for the treatment of samples containing halides and large amounts of sodium salts. Samples containing from 1 to 600 p. p. m. of boron have been analyzed. Literature Cited (1) Breckpot and Mevis, Ann. soc. sci. Bruzelles, B54, 99-119 (1934). (2) Brode and Steed, IND. EXG.CHEAL,Anal. Ed., 6, 157-9 (1934). (3) Drea, W. F.,S,Nutrition, 8, 229-34 (1934). (4) Dreblow and Harvey, IND. ESG. CHEM.,25, 823-5 (1933). (5) Duffendack, 0. S., Wolfe, R. A., and Smith, R. W., Ibid., Anal. Ed., 5, 228-9 (1933). ( 6 ) Kreamer, W., 2. anal. Chem., 97, 89-93 (1934).
(7) McHargue, J. S., and Calfee, R. IC., IND.EKQ.C H E M Anal. ., Ed., 4, 385-94 (1932). (8) Nitchie, C. E., Ibid., 1, 1-7 (1929). (9) Nutting R. D., Teztile Research, 5, 391-400 (1935). (10) Schubert. H.. and Cruse. Z. vhwsilc. Chem., A172. 143-55 (1935). Smith, D. M:, S. Inst. Metah, 55,417-25 (1934). Triche, Henry, Compt. rend., 199, 419-21 (1934). Waldbauer and Gantz, IND.ENG.CHEM.,Anal. Ed., 5, 311-13 (1933). RECEIVED February 25, 1937. Contribution from the Department of Chemistry of the Kentucky Agricultural Experiment Station. The invstigation reported in this paper is in connection with a project of the Kentucky Agricultural Experiment Station and is published by permission of the director.
FIQURE I Two carboys are mounted in a rack (Figure l), connected as shown, and the lower one is filled with water. Carbon dioxide from any convenient source, which need not be pure, is introduced through b and bubbled through the water until it is free of dissolved air. A flask containing a few chunks of dry ice is then connected at a and the water is forced from A to B, displaced air escaping through d. A carbon dioxide Kipp generator, which requires no precautions in filling, is connected at c and serves to maintain an atmosphere of carbon dioxide above the water in B. During operation the combustion tube is connected at a.
The time required to recharge a 40-liter (10-gallon) carboy is about 15 minutes. Over a period of months, since first setting up the apparatus, the blank has been 0.010 cc. within 10 per cent and has not changed either upon refilling or standing. Of this residual gas only 0.003 cc. is due to impurity in the carbon dioxide (1000 bubbles), the rest apparently being expelled during combustion from the combustion tube and filling. Because of the pressure under which the gas is stored, it has been found that one minute suffices for flushing out the combustion tube. RECEIYED May 19, 1937.
