ANALYTICAL CHEMISTRY
992 SUMMARY
A colorimetric method is described for the estimation of cortisone employing the interaction of the steroid with the anthrone reagent. Concentrations varying from 0.5 to 2.0 mg. per milliliter of either cortisone or cortisone acetate may he quantitatively determined by the method described.
LITERATIJRE CITED (1) (2)
187, 741 (1952).
(3) Graff, 31. M., AIcElroy, 3.T., and AIooney, A . L., Ibid., 195, 351 (1952). (4)
ACKNOWLEDGMENT
The authors are indebted to Morris >I. Graff for his helpful interest in the preparation of this manuscript. The authors are grateful to Elmer illpert of JIerck and Co., Inc., for supplying samples of cortisone and cortisone acetate used in this work.
Daughaday, W. H., Jaffe, H., and Williams, R. H., J . Clin. Endocrinol., 8, 166 (1948). Graff, hf. M., Holechek, J. J., and Collins, A. R., J . Biol. Chern.,
Lowenstein, B. E., Corcoran, A. C., and Page, I. H., Endocrinology, 39, 82 (1946).
( 5 ) IIader, W.J., and Buck, R. R., Ax.4~.CHEaf., 24, 666 (1952). (6) Porter, C. C., and Silber, R. H., J . Bid. Chem.. 185, 201 (1950). (7) Talbot, iK.B., Saltaman, A. H., Wixom, R. L.. and Wolfe, J. K., Ibid., 160, 535 (1945). (S) T'enning, E. H., Hoffman, 31. AI., and B!.owne, J. S. L., E I L ~ O crinology, 35, 49 (1944). RECEIVED for review December 3 , 1952.
Accepted March 6, 1953.
Spectrophotometric Determination of Thorium in Black Sands CHARLES V. BANKS, DONK W. KLINGMilN, AXD ChROL H. BYRD I n s t i t u t e f o r A t o m i c Research and Department of Chemistry, lowa State College, A m e s , Zowa YCREASED
interest in thorium chemistry during the past few
1-years has created the demand for a relatively simple quantitative method for determining small amounts of thorium in sands
and ores. The best source of this element is monazite sands, which contain 3 to 15% thoria. -4method for the analysis of monazite sands has been suggested by Banks and Bgrd (a), and in that paper it was noted that the method was not applicable to black sands without some modification. Black sands are a comples mixture containing many other minerals in addition to monazite sands; thus, their thoria contents are in the lower range of 0.1 to 1.0%. It is the purpose of this paper to outline a procedure for extending this method to these more complicated ores.
The thorium is stripped from the solvent phase by adding 20 nil. of water and again shaking for 20 seconds. The aqueous phase is drained into a 100-ml. volumetric flask; the water strip is repeated once more. The contents of the flask are diluted to volume. The water strip is frequently observed to have a faint yellow calor, probably due to the osidation products of mesityl oxide. This oxidation can he minimized b y avoiding the use of warm solutions during the estractions and working with maximum efficienc.v.
Table I. Analysis of Black Sands % Tho? Reporteda
% Tho, Found
0 33 0.25 0 089 0.163 0.53
0 . 3 2 i0 . 0 1 0.22 =t0 . 0 1 0 . 0 9 6 =t0 . 0 1 0 . 1 4 & 0 01
MATERIALS AND APPARATUS
The materials and apparatus used in this procedure are the same as those used by Banks and Byrd ( 2 ) . PROCEDURE
Preparation and Decomposition. The samples are ground to 200 mesh with a mortar and pestle and mixed t,hroughly to ensure homogeneity. It is important that the particle size be small in order to facilitate complete fusion as rapidly as possible. An approximately 0.2-gram sample is weighed, placed in a 50-nil. platinum crucible, and fused according to the niethod for monazite sands ( 2 ) . The cooled melt' is transferred to a 125-rn1. platinum dish, using 50 ml. of hot water. If difficult'y is experienced in complete transfer, a few milliliters of dilute hydrofluoric acid will facilitate the operation. Twenty milliliters of 48% hydrofluoric acid are added, and the mixture is digested under infrared heating lamps (or on the steam bath) for 30 minutes. The melt is pulverized and stirred occasionally during the digestion. Separation and Solution of the Fluorides. The hot mixture is transferred to a 50-nil. Lusteroid centrifuge tube and separated a t the full speed of the centrifuge for 3 to 5 minutes. The supernatant liquid is poured off carefully, and the residue is washed twice with 10 to 15 nil. of hot 16% hydrofluoric acid. (Caut,ion: The separation must be carried out in a well-ventilated hood.) This further facilitates the volatilization of any remaining silica. .1 hydrofluoric acid wash bottle can be construct'ed from a polyethylene bottle using a Teflon tubing tip. These fluorides are transferred with a minimum amount of hot water to a 150-ml. beaker containing 19 grams of aluminum nitrate 9-hydrate and 2.5 ml. of concentrated nitric acid. The solution is warmed on the hot plate to dissolve the fluorides as the fluoaluminates, evaporated to 20 ml., and allowed to cool. Extraction with Mesityl Oxide. The first part of the estraction is carried out according to the procedure of Banks and Byrd (2). If .a white suspension should form a t the interface of the aqueous and solvent phase during the extraction, it should be kept with the solvent phase. The nature of this suspension is not understood, but it usually forms during the extraction and the first scrub. I t tends to separate on standing but the extraction should be carried out as rapidly as possihle since nitric acid sle~v1y oxidizes mesityl oxide, turning it brorn.
0 . 4 8 =s 0 . 0 1
Difference 0.01 0.03 0.01 0.02
0.05 United States Bureau of Mines value obtained by the niethod of &onstadt and Eberle (3). a
Spectrophotometric Determination. The aliquot take11 tor analysis should contain about 70 micrograms of thoria, since the Beckman Model DC spectrophotometer is most accurate for an absorbance of about 0.45 (1). The aliquot is pipetted into a 100ml. beaker containing 10 ml. of 0.02% thorin and is diluted to about 40 ml. The pH is adjusted with a pH meter to about 0.92 using perchloric acid. The solution is transferred to a 50-ml. volumetric flask and diluted to volume; after thorough mixing it iq ready for measurement. The reference blank is a solution containing the same concentration of reagent and a t the same pH as the sample. The ahsortlance is measured on a Beckman Model DU spectrophotometer a t a wave length of 545 mH and a slit width of 0.17 mm. using 5-cm. Corex cells. Solutions should be read within 4 hours ai ter being prepared. Calculations. This system conforms to Beer's law a t least up to a concentration of 100 micrograms of thoria per 50 ml. Since the reagent thorin is available in varying degrees of purity the analyst should construct a Beer's law plot and determine the factor for converting absorbance to thoria concentration for this reagent. This can be accomplished by preparing a series of solutions containing known concentrations of thoria and plotting the concentrations against the absorbance. If the absorbance is plotted as the ordinate, and micrograms of thoria per 50 ml. as the abscissa, the best straight line connecting these points will have a slope equal to the reciprocal of the conversion factoi, RESCLTS
The black sands samples used in this study were obtained from Reuben Kronstadt of the Cnited States Bureau of Mines, Raleigh, S. C. Table I lists the values obtained in this laboratory and by the Gnited States Bureau of Mines.
V O L U M E 25, NO. 6, J U N E 1 9 5 3 The results obtained by the two methods of analysis agree quite well. DISCUSSION
This method of analysis has the same advantages of simplicity and rapidity as the method far the analysis of monazite sands of Banks and Byrd ( 8 ) . The separation of such small amounts of thorium from nsturally occurring mixtures of minerals and the precision attained confirms the analytical value oi this method. This method has not been extended to include analysis of noumonaeites. It has been established that the method will require some modification before it is applicable to these thaiiumcontaining 01e8.
993 ACKNOWLEDGMENT
The authors wish to express their appreciation to Reuben Kronstadt of the United States Bureau of Mines for providing the black sands samples used in this work. LITERATURE CITED
,
(1) Ayres, G. H., ANAL.CHEM., 21, 652-7 (1949).
(2) Banks, C. Y.. and Byrd. C . H., Ibid.,25,416-19 (1953). (3) Kronstadt, R., and Eberle, A. R.. Atomic Energy Commission. Re@. RMO-838 (1952). R ~ c s r v i nfor review January 19. 1953. looepted April 6 , 1953. Contribution No. 231. Institute for Atomic Research and Department of Chemistry. Iowa State College, Ames, Iowa. Work W&Q performed in the Ames Laboratory of the Atomic Energy Commission.
69. trans-Diethylstilbestrol Iontributed by AARRY A. ROSE, Eli Lilly & Co., Indianapolis, lnd., AND RALPH J. HINCH AND WALTER C. MCCRONE, Arm our Research F o u n d a t i o n of Illinois Institute of Technology, Chicago, Ill.
CR,
I
-.. 6H
H O - a - C =
I
.C
I
1 S t r u c t u r a l F o r m u l a of trans-Diethylstilbestml trans-Diethylstilbestrol forms solvates when recrystallized from chloroiorm, benzene, ether, 2-propanol, methanol, and acetic acid. These solvated crystals decompose readily under vacuum or on heating to give an anhydrous powder. Crystals formed by slow addition of hydrogen chloride to a basic aqueous solution are also hydrated. Anhydrous crystals suitable for opticd studies may he prepared by sublimation (Figuro 1). .The
powder x-ray pattern may he obtained on the sublimate or on the solvates after proper steps are taken to remove the solvent. CRYSTAL Mon~ao~dc~ Crystal System. Orthorhombio. Form and Habit. On sublimation long rods elongated parallel to e are formed (Fieure 2). Forms shown include the orisms I l l O l and 112Oi. ?he braohvdome 10111. the rnacrddames llOl!and {lhZ},andthebipyr;Lmid{lllj. .' Axial Ratio. 0.783: 1:0.277. Interfacial AnglesiPolar). 110 A ilO_= 103"51'. 120 A-iZO = 64'36'. 011 A011 = 149". 101 A101 = 141". 102A102 = 10920'. Cleavage. 001. OPTICALPROPERTIES Refractive Indices (5893 b.; 25" C.). LI = 1.594 f 0.002. P = 1.611 i0.002. Y = 1.73 f 0.01 (calculated from a,0, and
ZV).
-4
,Figure 1.
Crystals Formed b y S u b l i m a t i o n in a Kofler Block
Figure 2.
