V O L U M E 23, NO. 11, N O V E M B E R 1 9 5 1 selected so as to achieve a satisfacborg balance between these opposing trends. The conditions recommended-namely, t,he uae of a low panthenol potency, addition of 0.12 N buffer, and a flow rate of 18 ml. per minute-have been found satisfactory when applied to the usual types of single vitamin and mult,ivitamin preparations. If, for a particular product, panthenol recovery or pant'oyl lactone removal should he incomplete, these condit'ions may be modified as suggested above. If panthenol losses should still be encountered, the usual type of recovery test wit,h added panthenol could be used to est,ablish a correction for recovery or, as an alternative, the pt,her extraction method ( I ) employed. The resin technique has proved to be simpler and less time consuming than the ether extraction method. The equipment required is simpler, takes less laboratory space, arid eliminates the undesirable features of working nith a very volatile solvent,. Because the rrsiri adsorbs pantoic acid and pantothenat'e as well as pantoyl lactone, the extra assays required to correct for pantothenate or for pantoic acid formed at pH above 4.7 are eliminated. The inverse proportion bet'ween incubation time and activity of coenzyme A indicates better ut'ilization of coenzyme -4than of either pantoic or pantothenic acid during the early growth phases. Similar stimulation of ilcetcbacter suboxydans by bound forms of pantothenic acid has heen reported by Sovelli et al. ( 3 ) for coenzyme A and by King et al. ( 2 ) for PAC, a conjugate of pantothenic acid. If a separation of panthenol from bound forms of pantothenic acid such as coenzyme A, PAC, or the Lactobacillus bulgaricus factor of Williams et al. (6)is desired, it is likely that the resin column technique described could he applied. However, no data have been obtained in the present, experiments regarding the behavior of t,hese substances on the
1689 1R.I-400 resin. An alternative procedure would be to convert them t o free pantothenate by enzymatic liberation procedures (2, 4 ) prior to passage through the resin. The Acetobacter suboxydans assay for pantoic acid may also find application in determining the total pantothenic acid content of tissues. Preliminary trials indicate, however, that direct and/or alkaline hydrolysis of tissue homogenates is not suitable for release of the pantoic acid. Preliminary extraction and enzymatic liberation of pantothenic acid from the tissues may be necessary before hydrolysis to pantoic acid, Such a procedure would provide no information regarding the distribution of the various bound forms of pantothenic acid. ACKNOWLEDGMENT
The authors wish to thank B. Tabenkin and J . 8cheiner for their advice and cooperation in this work. LITERATURE CITED
(1) De Ritter, E., and Rubin, S. H., .\NAL. CHEM., 21, 823 (1949). (2) King, T. E., Fels, I. G., and Cheldelin, 5'.H., J . Am. Chem. Soc., 71, 131 (1949). ( 3 ) Novelli, G . D., Flynn, R. M., and Lipmann, F., J . B i d . Chem., 177, 493 (1949). (4) Sovelli, G. D., Kaplan, S . O., and Lipmann, F., I b i d . , 177, 97 (1949) * (5) XTilliams, IT. L., Hoff-J$rgensen, E., and Snell, E. E., Ibid., 177, 933 (1949). (6) Wollish, E. G., and Schmall, AI., .%N.AL. CHEM..22, 1033 (1950). RECEIYED March 2 , 1931. Presented before rhe Division of Biologicai Chemistry a t the 118th Meeting of the . ~ M E R I C L NC H E ~ I I C A I , S O C I E T T , Chicago, Ill. Publication 140.
Recommended Specifications for Microchemical Apparatus Carius Method Committee for the Standardization of Microchemical -Apparatus, Division of Analytical Chemistry, American Chemical-Society ,GLAZED
AL STEYERRLkRIC, Chairman, Ho#mann-La Roche Znc., A-utley, .\-.J . H. K. ALBER, Arthur H . Thomas Co., Philadelphia, Pa. V. A. ALCISE, Experiment Station, Hercules Powder Co., Wilmington, Del. E. W. D. HUFF-MAN, Huffman Microanalytical Laboratories, Denver, Colo. E. L. JOLLEY, Corning Glass Works, Corning, N. Y . J. A. KUCK, College of the City of New York, IV. Y., and American Cyanamid Co., Stamford, Conn. J. J. MORAN, Kimble Glass, Division of Owens-Zllinois Glass Co., Vineland, N. J . C. 0. WILLITS, Eastern Regional Research Laboratory, Philadelphia, Pa.
R
ECOLILIESDED specifications
for microchemical apparatus used in carbon-hydrogen, Dumas nitrogen, halogen, and sulfur determinat>ions( 3 ) and in the micro-Kjeldahl nitrogen determination ( 5 ) ,for the all-metal needle valve of the Hershberg-Southworth type ( 4 ) ) and for 3 new design of rubber as well stoppers for microchemistry (a), as the proposed program for the future ( I ) , have been published. This report includes recommendations for the combustion furnace and t\yo types of combustion tubes for the micro-Carius procedure (halogen, sulfur, arsenic).
Figure 1.
Combustion Tube
Combustion Furnace. A portable furnace suitable for conducting the reactions in the Carius procedure should have a t least four wells of approximately
16-mm. inside diameter and 225 mm. long. The wells should be held a t a fixed inclined position of approximately 45" or should be adjustable. A device for pushing the combustion tubes from the individual wells should be provided. The temperature in the wells must be maintained a t approsimately 310" C.; the temperature at any point should not vary more than 5 5 ' C. from the operating temperature. [The temperature of an electrically heated furnace must be maintained at 310" C . with 100 volts (minimum).] The furnace temperature should be adjustable. -4device that shows when the furnace is in operation and a temperature indicator should be provided. The furnace must be equipped with safety devices t o confine broken glass in the event of an explosion. Combustion Tubes (Bomb Tubes). Recommended specifications for the combustion tubes take into account the fact that the details of the procedure vary, particularly in the amount of fuming nitric acid used. hccordingly, two types of tubes are recommended-heavy-Tvalled and thin-walled. The type of glass to be used is specified beloa. The specifications are designed for a maximum operating temperature of 300" C. The length of the sealed tube between
1690
ANALYTICAL CHEMISTRY -
Table 1. Recommended Specifications Coinbustion Tube
Wall Thickness 0.1). Mm. .if m , Heaw-walled 2 . 3 zk 0 . 3 13 f 0 . 8 Thin-walled
I 1
+0
2 13
i0
7
Len t h of Sraled Volunie of H S O a Tugbe betiwen (8 Gr. a t 60' F., Bottom nnd Stiii.t of X;proximately Temp Length Taper a t Shoulder 1.5) OC .lIm , .Urn. '1111. 210 5 10 I 5 O r o 173 N o r e than 0 . 3 250 (volume should not exceed 0 , 7 ) 240 = 10 180 t o 210 0 . 3 or less 30(1
--______
the 1)ottoni and the start of the taper a t the shoulder should I)(! 150 to 175 nun. for the heavy-walled tubes and 180 to 210 inin. for the thin-walled type. The glawfi should have a coefficient of linear expansion not exceeding 0.0000040 em. per em. per 1" C., with a softening point of 820" ('. (Corning Pyrex 7740 or equal). Tubes at one end
should have a closed round bottom of about the same wall thickness as the side ~aallsand a t the other end should be open anti glazed. Tubes must be well annealed. The thickness of the wall and the length depend upon the volume of nitric acid used. Table I gives the recommended spec ifications.
LITERATURE CITED (1) ASAL.( ' H ~ M . .21, 651 (1949). ( 2 ) Steyermark, -41, Ibid., 22, 1228 (195U). ( 3 ) Steyermark, AI, Xlber, FI. K., Aluise, V. A., Huffman, E. W. D., Kuck, J. A , , Moran, J. .J.. and Willits, C. O., Ibid.. 21. 1555 (1949). (4) Itid., P. 1283. (5) Ihid., 2% 523 (1951). R E C I : I ~ . E D &l,telnber 7, 1951.
Determination of Aluminum in Copper-Base Alloys JORMA GINNUNEN AND BENGT ilIERIKANTO Outokumpu Oy, Metalworks, Pori, Finland
'IIE classical methods for t,he determination of aluniinum in nietallurgical products are tedious and inaccurate. The introduction of the mercury cathode cell and its application to analytical separations Initde possible the rapid anti accurate dctermination of aluniinuni in various technical products. This method is suitable for niost alloys. For niore rapid analysis, solution of the sample in nitric x i d and evaporation with sulfuric acid to fumes can be avoided by dissolving the sample (1) in 1 to 4 sulfuric acid with dropvise addition of 30% hydrogen peroxide, ( 2 ) in hydruchloric acid and 30% hydrogen peroxide, or ( 3 ) in nitric acid. Electrolytic separations in hydrochloric or nitric acid solution can be made if the circuit is closed before the solution is added t o the cell. The time required for elect,rol) can be miiiiniized by reducing the sample size to m amount consistent with the desired accuracy, and the mercury cathode cell can be designed for conveniently handling a small sample. T o eiisure thut copper and zinc have been quantitatively removed, the electrolg-zed solution should be tested n-ith hydrogen sulfide. blthough the determination of aluminum, if performed colorimetrically or volumetrically, can be rapid, this procedure docs not fulfill the requirements of it rapid control method and must be regarded as it precision method. Froni Table I, it is evident that the acid used dues not affect the percentage of aluniiriuni found.
Table I.
Effect of Acids in Electrolj te Aluminum F o u n d ,
Electrolyte Sulfuric acid Xitric acid Hydrochloric acid
% 8.83 8.74 8.89
Attempts have been made to develop a rapid method for determining aluminum in iron and steel (3,fO),in zinc-base alloys ( I I ) , and in copper and nickel slags ( 6 ) . Aluminum in copper-base alloys can be determined by the method set forth below. The sample, 0.4 to 1 gram of alloy, is dissolved in 3 to 5 nil. of nitric acid. The solution is boiled, and 5 drops of 1 t o 1
sulfuric acid, 20 nil. of 20% tiirtiwir acid, and 20 nil. of 2570 arnmonium chloride are added. .Mer dilut'ing with hot water to 100 ml., 2 to 3 grams of sodium sulfite dissolved in water are added, and boiling is continued until the solution turns pale. Then in a fume hood potassium cyanide is slowly added ,until the solution is colorless, and 3 to 4 grams of potassium cyanide are added in excess. T o precipitate aluminum, 15 ml. of 5% alcoholic osine solution are added. After 5 minutes, the precipit.ate is filtered and washed, first with hot water, then with cold water. The aluminum may be determined as alumina by adding oxalic acid to the precipitate and igniting a t 1200' C. The precipitate may also be dissolved in 50 ml. of cold 1 to 3 hydrochloric acid-alcohol and diluted to 100 ml., and the aluniinuni determined by the bromate method.
Sonic typical results with this niethod are given in Table 11. Table 11. iinalysis of Aliiniitiuni-Containing Sample by Oxine Jlethod AIaterial Aluminum bronze Manganese bronze llanganese bronze
-41riniin u in
AI I I in in' I i n
