V O L U M E 20. NO. 1 1 , N O V E M B E R 1 9 4 8
c
112s
Cell Dimensions. a = 18.66 d.; b = 21.55 d.; c = 14.48d. Formula Weights per Cell. 12. Formula Weight. 409.5. Density. 1.387. OPTICALPROPERTIES (determined by V. Gilpin, checked by W. C. McCrone). Refractive Indices. (5893 i.; 25" C.). a = 1.650 0.002. ia = 1.740 + 0.002, y = 1.8! + 0.01. Optic Axial Angles. (5893 A.; 25" C.). 2V = R.5' -.
5
f
> v.
lane. 100. e Refrantion
Pnsitivo
Figure 1. Orthographic Pr for Typical Crystal of 1,3,5-Tri(p-el..-. .,,,L.bL.,,l)benzene (100); prisms, (110) and (210); brachydome, (011); and macrodome { 1011, Axial Ratio. a : b : c = 0.866:1:0.67_. Interf%cidAngles (Polar). 110 A 110 = 98"lO'; 210 A 210 = 133"; 101 ~ i o =i 104~20'; o i l A O I I = me. X-RAYDIFFRACTION DATA(determined by ,I. Whitney, I. Corvin, and M. Tull). Principal Lines d 10.86 8.52 7.86 7.43 7.10 6.80 6.37 6.09 5.70 5.39 5.02 4.87 4.66 4.57 4.30 4.15 3.97 3.89
I/Ii 0.33 Very weak Very weak Very weak v e r y weak Very weak very weal. Very weak 0.39 0.50 Very weak Very weak 0.44
Very weak 0.61 Very weak 1.00 Very weak
d
Ill, ~,
3.80 3.7o 3.59 3.4s 3.44 3.34 3.30 3.21 3.11 3.03 2.91 2.84 2.79 2.75 2.70 2.64 2.66 2.52
0.39 Very N e a t 0.33 Very weak Very weak 0.22 Very weak 0.56 Very weak 0.33 Very weak Very weak Very weak Very weak very weak Very weak Very weak Very weak
~.
subiimationor decomposition.
Crystallization occurs spontane-
to alpha, the obtuse bisectrix, and :he optic axial a& is85". A thvmol mixed fusion is not practical because of the high
solution
Optical Society of America L. T. HALLETT, Assoeiata5 Editor
T
HE 33rd meeting of the Optical Society of America, held October 21 to 23 in Detroit, attracted 550 to the thre+day
meeting. Those attending were rewarded with a record of 76 papers and 8 splendid apparatus exhibition. The local committee organized the meeting extremely well and deserves much credit. The Friday evening banquet featured the presentation of the Adolf I o m b Medal to David S. Grey of the Polaroid Corp. for his work on a combination of mirrors and lenses for removal of astigmatism and spherical aberration in optical systems. Stanley S. Ballard reported on his recent trip to Europe and said that Holland is again very active in optics, Phillips Labomtory being among the best. At a conference held in Delft, the International Commission of Optics stated its aims to be (1) to gather and distribute reports of optical research work and progress prior to publication, necessary because of the great delays in time now taken to publish original work, (2) arrange traveling fellowships, (3) standardize definitions and terms, and (4) sponsor conferences. The next meeting is scheduled for the summer of 1950. C. F. Kettering, director of the research laboratory of General Motors Corporation, gave a n interesting and entertaining afterdinner speech in which,he stressed need for a further study of
photosynthesis to unravel the mystery of its mechanism. Combustion research conducted by the automotive industry has led to a more efficient use of motor fuels and thus has extended th? present oil supplies. The contributions of these researches have been substantial when one considers that the addition of tetraethyllead to gasoline8 ha3 inoreased combustion efficiency one third, and use of higher compression ratios ha3 effected an equal improvement in engine efficiency. To prepare for the day when oil is no longer available, fundamental studies should be undertaken in energy production and utiliaation. Atomic energy now holds the spotlight, hut the effective use of solar energy should receive more careful study, particularly in regard to utilization and storage. I n these studies the members of the Optical Society with their knowledge of instrumentation can play an important part. .Keb tering finally warned that as we advance in knowledge, we, of course, must first learn what has been done, hut real accomplishment must seek knowledge which in terms of known concepts often seems untenable-thus we must not he hampered by past traditions. The papers of most interest to analysts are abstracted herewith,
1126
ANALYTICAL CHEMISTRY MOLECULAR SPECTROSCOPY
Infrared Absorption Spectra of Some Benzene Derivatives. EARLE K. PLYLER, National Bureau of Standards, Washington, D. C. The infrared absorption spectra of fourteen benzene derivatives, in the liquid state, have been measured to 38p. The main emphasis has been placed on the region from 15 to 38p. By the use of a thallium bromide-iodide prism the region from 22 to 381 was measured with cells up to 2 mm. in thickness. Bands were observed in mesitylene a t 30.0 and 3 6 . 4 ~in~ toluene at 2 8 . 7 ~ . Bands were also observed in chlorobenzene a t 24.1 and 33.7p, in bromobenzene a t 22.2 and 3 1 . 9 ~and ~ in iodobenzene at 22.2~. I n o-bromoanisole the bands appeared a t 22.9, 30.5, and 35.8p, and in p-bromoanisole a t 30.8 and 3 7 . 9 ~ . The absorption spectra of six other benzene derivatives containing methyl and ethyl groups have been observed. Data were presented on the absorption spectra in the region from 2 to 15p for some of these compounds. Infrared Spectra of n-Propane, 1-Deuteropropane, and 2Deuteropropane. H. L. MCMURRY, V. THORKTOS, A N D F. E. CONDON, Phillips Petroleum Co., Bartlesville, Okla. The infrared spectra of very pure n-propane, 2-deuteropropane, and I-deuteropropane have been obtained using a Perkin Elmer model 12B spectrometer. The spectrum of n-propane exhibits the same features reported by Wu and Barker, with the important exceptions that the sharp bands found a t 720 and 1179 em.-’ in their work are absent in the present spectrum. These bands must be foreign to propane. The data show unambiguously that the propane frequencies a t 748 and 1052 em.-’ arise from motions of the CH2 group. These bands are strongly modified in 2deuteropropane and much less so in 1-deuteropropane, The work of Sheppard and Sutherland [Nature, 159, 139 (1947)] and of Jones and Sutherland [Zbid., 160, 567 (1947)] has already established the 748-cm.-l propane band as caused by a rocking of this group about an axis in the CS plane and normal to the molecular symmetry axis. The shape of the 1052-cm.-’ propane band and its behavior in the deuteropropanes show it to be due to the wagging of the CH2 about an axis normal to the Cs plane. While the other propane frequencies cannot be assigned so unambiguously, possible improvements over previous assignments were discussed. Assignments for the bands in the deuterated propanes were also discussed. Infrared Spectra of Alcohols. C. Co., Midland, Mich.
W.POVSC, Dox Chemical
The infrared absorption spectra of a number of alcohols were analyzed using a double beam sodium chloride spectrometer with particular attention to frequencies associated with bending motions of the hydroxyl group. The corresponding deuteroxyl compounds of some of the alcohols were also investigated in order to distinguish the hydroxyl frequencies from those due to other modes of vibration. The effect of dilution on the associated bands was considered, and characteristic differences were pointed out among many secondary and tertiary alcohols. Practical Aspects of the Preparation and Application of an A. G. Ksox, AND J. F. Infrared Bibliography. J. D. STROUPE, WOODMAN, Rohm I%Haw Co., Philadelphia, Pa. For the efficient application and dewlopment of infrared spectroscopy the extensive original literature must be made readily available by means of a bibliographic system. It is particularly necessary to devise a satisfactory means for recording, filing, and making effective use of infrared absorption spectra. The Kevsort system of Tingey and Hampton [ J . Optical SOC. Am., 37, 984 (1917)l seems best designed to fill this need. The present paper described the practical aspects of planning, preparing, and applying a two-card infrared bibliography of similar type. Beginning with the planning of the body and coded contents of both “abstract” and “compound” cards, the important matters of personnel and time required for the preparation of the bibliography and for its maintenance, growth, and application Tyere discussed The results of experience in the use of an empirical formula indey, the representation of literature spectra on compound cards, and the performance of a suitably coded and punched spectra frequency field in correlation and identification work were discussed. APPLIED ABSORPTION SPECTROSCOPY
Presentation of Absorption Spectra Data. WALLACER , BRODE,Kational Bureau of Standards, IT-ashington, D. C.
The application of qualitative and quantitative methods of analysis as well as theoretical studies on molecular structure to absorption spectra data, in the saine manner that these measurements are applied to emission spectra data, requires considerable development and coordination of effort to be effective. A survey was presented of the problem involved, the method of recording and describing effects, the notation systems, and general recommendations on the methods of graphical presentation. The program for the development of a cooperative program with a center for the issuance of standard absorption spectra data a t the National Bureau of Standards was discussed. Ultraviolet Absorption Spectra and the Structures of the Isomeric Amidones. L. A. STRAIT,W, D. KUNLER,P. P. T. S.~H, E. L. ALPEN,AND F. N. H. CHANG,University of California, Berkeley, Calif. The ultraviolet absorption spectra of the isomeric amidonea (morphine substitutes) and their nitriles have been measured in ethyl alcohol, hexane, and acidic and basic water solutions. The spectra are characterized not only by the expected phenyl absorptions near 260 my but also by an apparently anomalous absorption band near 300 nip and an unexpected appearance of a strong band below 260 nip in the spectrum of amidone and its nitrile in basic and hexane solutions, in contrast with isoamidone and its nitrile. The differences (interchange of a methyl group between adjacent carbon atoms) in the “accepted” structures of amidone and isoamidone and their nitriles are incompatible with these spectrum differences. The authors propose that amidone has only one rather than the accepted two phenyl groups on the KO.4 carbon atom to explain the spectrum characteristics. The spectrum of isoamidone is compatible with the accepted two phenyl groups on the same carbon atom. These differences,in structure also account for the otherwise inexplicable discrepancies in their chemical behaviors. Amidone nitrile has a corresponding change in structure. The strong band below 260 mp is attributed to the enol and enamine structures, thus possible only in amidone and its nitrile. The band a t 290 to 300 mp, present in the amidones and absent in amidone carbinol and the nitriles, is associated with an a-phenyl carbongl structure. Infrared Absorption Analyses Used in Control of a Pilot Plant Triptane Process. D. L. FRY,Research Laboratories Division, General Motors Corp., Detroit, Mich. The methods described are of general interest because they illustrate the effectiveness of infrared in the analysis of hydrocarbons and the control of experimental and pilot plant processes. A number of particular problems n-ere discussed. These problems vary in complexity from analyzing for two components in a mixture of tyo, to analyzing for three components in a mixture of twelve or six in a mixture of six. I n some cases the analyses are possible only for certain ranges of concentration; in other cases the concentrations of the components can vary from 0 to 1007,. The analyses were determined with an accuracy of * l % ,providing the range of concentration of the various components stayed within the limits for which the method was calibrated. In some cases it was necessary to set up calibration curves with inadequate standard samples. Even under these adverse conditions it was possible to attain reasonable accuracy and to make a contribution to the problem of controlling the pilot plant. In control problems it is frequently not important to know the absolute composition; it is sufficient to know relative values of concentration from day to day. Detection and Control System for a Double Beam Infrared I-,WHITE,The PerSpectrometer. MAXD. LISTONASD JOHX kin-Elmer Corp., Stamford, Conn. The detection, amplification, and control system for a double beam, per cent transmission 1‘s. wave length, infrared xpectronieter were discussed. Its general construction and performance vere described by Khite and Liston. A fast pin-type vacuum thermocouple has been developed which peTmits light modulation a t 13 cycles per second, wit,h only 30% loss in response. A simple 13-cycle amplifier servo system, espressly developed for double beam infrared spectrographs, n-as described. This system eniploys a special high gain input transformer and preamplifier Iyhich is located at the base of the thermocouple to eliminate the pickup troubles experienced in previous instruments. An automatic wave-length drive decreases the scanning speed when detail spectra are present. An electrically cammed slit control that permits easy variation of slit programming Ivas disclosed. Various ovcrall response characteristics and their noise rs. spectruin following ability n-ere described.
1127
V O L U M E 20, NO. 1 1 , N O V E M B E R 1 9 4 8 Construction and Performance of a Double Beam h f r a r e d spectrometer. JOHN U. WHITE. ~ N DMAX D. LISTON,The Perkin-Elmer Corp., Stamford, Conn. A new double beam infrared spectrometer recording directly in per cent transmission us. wave length has been built on the principles described by Wright and Hersher [ J . Optical Soc. Am., 37, 211 (1947)l. Its detection and control systems mere described by Liston and White. The spectrometer and recorder are a single unit (40 inches long, 22 inches high, 18 inches wide) with external amplifier and power supplies. The instrument makes direct reading transmission records on 32 inch X 11 inch charts, employs a 60” Littrow mounted rock salt prism with 60 X 75 mm. faces, and has 5 inches of length available for sample cell? in each beam. K a v e lengths and slit widths are read directly on Veeder counters. Special features are accuracy, convenience, and wide range of operating conditions. Available wave-length drive speed varies from about 2 minutes to 300 hours for the rock salt region, speed of response from 4 seconds to over a minute for full scale, 13 ith the possibilitv of a further increase to 5 minutes if needed, resolution from close to the theoretical limit of the prism to about a tenth as much, paper drive speed giving uniform scales from 1 to 50 inches per micron by integral factors. By changing cams, spectra can be recorded on constant wave number or other scales Prisms of LiF, KBr, and other materials can be accommodated.
Infrared Instrument for Industrial Product Control. N. C. JAWSOK, T. R . KOHLER,A K D 0. G. KOPPIUS,Philips Laboratories, Inc., Itvington-ori-Hudson, S . I-. An infrared differential comparator with no dispersion has been built for routine product control in industrial plants. Good stability is obtained without thermostatic control by means of a flicker system using a single source of radiation, a single radiation detector, and alternating current amplification. rl thermistor bolometer is used as the heat-sensitive element; the samples of known purity and unknown purity are compared six times per second and the difference in absorption is recorded. The design, construction, and operating characteristics of the instrument were considered in some detail.
isotopic effects. The results of a preliminary investigatioi! of this effect in uranium isotopes were presented. Spectrum shifts ab large as a wave number between the U 2 3 5 and UZ35 spectra are not un; common, usually toward the violet for the lighter isotope. These xave-length differences have been correlated to the spectroscopic energy systems of U I and L I1 arid are found to be of two types: (1) a simple isotopic displacement arising from configurationnucleus interaction, and (2) a complex isotopic displacement arising from perturbations between close-lying levels. The niagnitude of the shift in U I is generally of the order of 0.3 cm.-’, but ranges from -0.7 to 1.5 em.-’ in U 11. Configumtions involving the s* electron group show the largest isotope shifts, indicating an addhive type of interaction for the s electrons and the nucleus. Spectrographic Analysis of Vitallium Alloys. Y. T. SIHYOSEX, D. L. FRY,R . E. NUSBACM, AKD R. R. BAUYGIRTNER, Research Laboratories Division, General Motors Corp., Detroit, hlich.
A spectrochemical method of analysis for control purposes in casting V-itallium n-as described. Thr need for such a method rvas so urgent that only a small amount of development time was possible; control analyses were being niade within 3 days of the time the problem was submitted. Improvements were niade in the method in the course of the work. Reproducibility and accuracy data were given in the paper. This problem illustrates that a great deal of analytical work can be done with a spectrograph even though accurate comparison standards at’e not available. Spectrochemical Determination of Hafnium-Zirconium Ratios.
CYRVSFELDMAN, Oak Ridge Sational Laboratory, Oak Ridge, Tenn.
A spectrochemical technique is presented for determining hafnium-zirconium ratios in the range (Hf X 100)/Zr = 0.073 9.23 by weight, with and without the aid of hafnium-free zirconium preparations. The sample is brought into solution in 10% sulfuric acid and sparked by the porous cup technique. The intensity ratio Hf I1 2641.4061Zr I1 2761.911 is measured, and the Hf/Zr ratio read from a standard curve. I
APPLIED SPECTROSCOPY
Recent Infrared Work at Cambridge. G. B. B. 11. SUTHERLAXD,Pembroke College, Cambridge, England.
A Rapid Mobile Analyzer for Minute Amounts of Lead in Air. HEXRYAUGHEY, E. I. du Pont de Semours & Co., Rilmington, Del.
Advances in the technique of infrared detection were discussed, particularly the development of lead telluride cells, which are sensitive to 5 . 5 , ~and far superior to thermocouples or bolometers in sensitivity and speed of response. Applications of infrared methods of analysis to the structure of large molecules were discussed, with special emphasis on proteins and on diamond. Some recent work on polarized infrared radiation and on atmospheric absorption was also outlined.
Atmospheric contamination by lead presents acute problems in analysis and control to the chemical industry. A mobile instrument of extreme sensitivity has been developed which furnishes a rapid indication and an approximate assay of localized relatively high concentrations of lead, combined or elemental. Samples are drawn through a condensed spark discharge adjusted to minimize air lines and to excite the lead spectrum TI hich is photographed with a small quartz instrument. Visual examination of a Penes of exposures provides data on lead concentration as a function of time and location. A sensitivity of better than 1 part in 20,000,000 can be maintained in routine operation. Instantaneous response has been realized by substitution of the photoelectric Geiger counter for the photographic plate, as described 111 detail by Iioppius.
A Spectrochemical Method for the Determination of Uranium. L. T. STEADMAS, I-niversity of Rochester School of RIedicine and Dentistry, Rochester, S. Y.
Microgram amounts of uranium are analytically determined by means of the direct current carbon arc and a Bausch & Lomb medium quartz spectrograph. If necessary, the uranium is separated from extraneous materials by a modification of the ether extraction method of Furman and co-workers. The sample is placed in the negative electrode, the light from which is focused on the prism. The sample is burned in the crater of a purified graphite rod or, for higher sensitivity, is arced on the flat end of a carbon electrode. Relative intensities are determined by a sector method employing a rotating half-cylinder in front of the slit, with a slit width of 10 microns. A 50-fold increase in sensitivity is obtained by adding about 10 mg. of rubidium chloride as an enhancing agent to the electrode along n-ith the sample. Lines measur$d are the unresolved ouranium lines 2882.6, 2882.7, and 2882.9 A . , and the line 2650.8 ;1of the internal standard platinum. The calibration curves extend from 0.02 to 20 micrograms of uranium in the arc. The standard error of a single determination is about j=l5G$.
A preliminary Investigation of the Spectra of Uranium Isotopes. J. RASD RICSALLY, JR.,Carbide and Carbon Chemicals Corp., Oak Ridge, Tenn. The isotope displacement, effect [S.Tolansky, “Hyperfine Structure in Line Spectra and Nuclear Spin,” London, RIethuen and Co., Ltd., 19461 n-as discussed n-ith relation to other spectro-
Detection of Lead in Air with the Aid of a Geiger-Muller Counter. 0. G. KOPPICS,Philips Laboratories, Inc., Irvington-onHudson, S.Y. A detector of lead in air was described. I t utilizes a spark source for the excitation of the lead spectrum, a small quartz spectrometer for the dispersion, and a quartz Geiger-Mfiller counter for the detector of the radiation. The lower limit of detection is of the order of 20 micrograms of lead per cubic foot of air. The in. strument is mobile and ideally suited to locate areas of high lead concentration in air.
Stainless Steel Analysis with the Direct Reading Spectrometer. JACOB H. JURX~IS ASD JOHK STERSER,Baird Associatrs, Inc., Cambridge, 3Iass. With minor modification, the direct reading srectronieter has beeii applied to the rapid analysis of chromium, nickel, nianganese, and silicon in stainless steels. TTorking curve +ts were described, and their application to practical prohlenis i n industry was discussed. Repeatability results were presented, showing that characteristic reproducibility of the instrument fall-: well Tithin the limits required for industrial control.
ANALYTICAL CHEMISTRY
1128 APPLIED EMISSION SPECTROSCOPY
Spectrographic Light Sources. R. A. WOLFE,Yniversity of hlichigan, Ann Arbor, Mich. A survey R as made of the important facts regarding the operation of arc and spark sources, including in particular a discussion of high and low voltage alternating current arcs, interrupted direct current arcs, and controlled sparks. Influence of secondary discharge wave forms, frequency of discharge, gap and circuit resistance, sample pin shapes, and other factors on the accuracy of analytical results were examined. For maximum sensitivity the arc source is considered best and the spark source for accuracy. I t was pointed out that even with the same type of alloy setting conditions for determining an element satisfactorily when present in one concentration may give totally erroneous results if the same alloy containing a different percentage of the element is analyzed. The electrical parameters necessary for constant light intensity and the means of dedcribing such parameters to other workersin the field were dibcusscd. I t is now entirely feasible by properly describing the condition under which spectrographic results are obtained to duplicate results in another laboratory, and the desirability of keeping such records was stressed. The fundamental problem on which much excelleat work has been done but which must receive further study is the improvement of sources and this is t r u e whether photographic or direct reading instruments are uwd. Criteria for High Precision Analyses with Direct Current Arc Excitation. VELMER A. FASSEL, Institute for Atomic Research, Iowa State College, Ames, Iowa. The direct current arc between graphite electrodes possesses definite advantages in convenience, general application, and sensitivity as an excitation source for the spectrographic analysis of inorganic materials. However, the poor reproducibility usually associated with this discharge greatly limits its usefulness for quantitative analyses. In a method recently reported [V. A. Fassel and H. A. Wilhelm, J . Optical SOC. Am., 38, 518 (1948); 38, 666 (194811 for the determination of major amounts of gadolinium and yttrium in complex rare earth oxide mixturer, it was observed that the standard deviation was only 2.0 and 2.5%. The precision was thus comparable to that obtained from more carefully controlled excitation sources. The results from a quantitative study of vaporization rates, intensity diagrams of the internal standard line pairs along the longitudinal axis of the arc discharge, and the effect of large changes in external excitation conditions on the intensity ratios show that this high precision can be attributed to nearlv ideal internal standard compensation of excitation variables. The data presented indicated that the difficulties of direct current arc excitation can largely be overcome by satisfying the essential criteria of the internal standard principle. An Air Interrupter Type Spectrographic Light Source. J. H. 1:ahs A X D R. A . KOLFE, rniversity of Michigan, Ann Arbor, Rfich. The principal feature of this source is an air interrupter, some of whose operating characteristics were described [J.H. Enns and R . A. Wolfe, Am. SOC.Testing Materials, Special Tech. Pub., 76, (H46); J. H. Enns and R. A. Wolfe, paper a t Optical Soc. Ani. meeting, Feb. 21, 19471. This paper presented a general technical description of the source to illustrate its unusual flexibility. A procedure followed in selection of source parameters was outtined. Several examples were given to show the most suitable source conditions for some samples of widely different types.
A Combination Spark-Arc Source Unit for Spectrochemistry. RI. F. HASLERAND J. IT. KEMP,Applied Research Laboratories, Glendale, Calif. The alternating current arc unit has enjoyed a certain popularity because of the simplicity of its circuit and its sensitivity as a spectrum source. However, it has suffered from the small gap spacing required and its very low electrical efficiency. Both defects can be easily eliminated by using a spark-ignited arc. The authors described such an arc utilizing a 900-peak volt transformer to supply 3 or 6 amperes in the arc circuit and ignited with high voltage power from a standard spark circuit. Power in the ignitor is reduced by means of resistance in the oscillating circuit of the spark. The spark circuit is a conventional rotary gap arrangement except that a single control gap is utilized by means of a brush system on the rotary gap. This plus a large diameter rotor, large tungsten electrodes, and ultraviolet irradiation pro-
vides &d precision a t high intensity. The unit is particularly suited for routine metal analysis n-ith either a spectrograph or a quantometrr. Instrumentation for Direct-Reading Spectrochemistry. M.F. HASLER,J. W. KEMP,AND D. R. PROCTER, Applied Research Laboratories, Glendale, Calif. The various systems of direct-reading spectrochemical analysis reported to date were analyzed in comparison with a new system proposed by the authors. The problems connected with the spectrometer and the recording system were analyzed in detail and the relative merits of the various proposed solutions were considered. A direct-reading adapter suitable for grating spectrographs and utilizing the newly developed system was described. SPECTROCHEMICAL AYALYSIS OF NOYMETALLIC MATERIALS
Progress and Prospects in the Spectrochemical Analysis of Nonmetallic Materials. ROBERTIT. SMITH,AC Spark Plug Division, General Motors Corp., Detroit, Mich. Progress made by spectrochemical analysia, in the field of nonmetallic materials has been slow considering the great need for rapid, reliable analytical methods. Analytical control of nonmetals is important in such diversified fields as industrial hygiene, agriculture, paint and varnish manufacture, biological chemistry, ceramics, and foundry operation. Special problems are involved in the analysis of nonmetallic materials as compared to metals and alloys. Proper sampling and excitation present the greatest difficulties in setting up reliable procedures. Sample volatilization and excitation by arc or spark are complicated processes, but are successful for metals and alloys which are electrically conducting and physically homogeneous. Most nonmetallics are poor electrical and thermal conductors and are heterogeneous in nature. Many are extremely refractory and have nonequilibrium structures subject to chemical change during volatilization with subsequent physical effects on spectral line emission. Although not the ideal source, the carbon arc is used extensively for the excitation of nonmetals because it is readily adaptable to spectrography and permits attainment of very high temperatures. A few typical examples of successful analytical control of nonmetallic materials served t o show how the essential difficulties were overcome. Spectrographic Analysis of Alumina in Silica Brick. P. R. IRISH,Bethlehem Steel Co., Bethlehem, Pa.
A method for determining alumina in the range of 0.25 to 1.509, in silica brick was described. The procedure for analyzing thi. nonconducting material, while not new, has not been prominently employed. With this method the sample in powdered form is fused in a small electric furnace a t 1100" C. with alkali salts, sodium carbonate, and borax along with an internal standard element, columbium oxide. FThile the fusion material containing the brick sample in solution is molten, a carbon electrode is dipped into the molten pool. The fusion material adheres to the carbon, thus forming an electrode that is tipped with the solidified fusion material which contains the brick sample and internal standard element in solid solution. Electrodes thus formed are rugged enough for use with a spark source. In a test of the accuracy for 92 saniples only three samples showed deviations greater than 0.037: A1203from the average umpire analysis of four chemical laboratories. The method is well adapted to routine control and gives the usual spectrographic speed, the elapse time of a single determination being 20 to 25 minutes. The Spectrographic Determination of Fluorine in Organic Substances. CHARLESW. RANKIN,New York State Police Scientific Laboratory, Albany, N. Y. During the recent war, sodium fluoroacetate or 1080 was developed and proved highly effective against an unlimited variety of rodent species. A serious objection to its use is it high toxicity for all mammalian species, dogs having succumbed to doses as lox as 0.1 mg. per kg. as compared with a lethal dose of 2 mg. per kg. for sodium fluoride. When 1080 became commercially available it was natural that this laboratory should receive cases of quapected 1080 poisoning. The author became interested, therefore, in determining fluorine in trace quantities by spectrographic meth(2ds. Two methods were attempted: the detection of the 5291 A . band of CaF2 [Papish, Hoag, and Snee, ISD.ENG.CHFLM., ASSL. ED., 2, 263 (1930)l and the detection of fluorine in the high current density spark [ Pfeilsticker, 2.Jletallkunde, 33, 26772 (1941)]. Using eithrr method, as little as 100 micrograms of LO80 have heen detected.
V O L U M E 20, N O . 1 1 , N O V E M B E R 1 9 4 8
1129
Ultraviolet Absorption Spectra of Biological Compounds at Low Temperatures. R. L. SINSHEIMER, J. E. SCOTT,AXD J. R. LOOFBOUROW, Massachusetts Institute of Technology, Cambridge, Mass. It is often possible to increase the detail observable in the absorption spectra of complex molecules by refrigeration of the absorbing substance. The investigations reported sought to take advantage of this principle to improve the spectroscopic characterization of biological compounds. Special methods have been devised for this work. Spectra of purines, pyrimidines, and derivatives, and of amino acids and derivatives, taken a t liquid nitrogen and liquid hydrogen temperatures were presented. Empirical generalizations, drawn from the results thus far ohtained, were discussed. Optical and Electrical Alterations to a Michigan Microphotometer. H. H. GROSSMAN, E.W. PETERSON, J. L. SAUNDERSON, AAD V. ,I. CALDECOURT, Spectroscopy Laboratory, Dow Chemical Po.. Midland, Mich. -1microphotometer of the type described by Vincent and Sa\+w r [ J .Optical SOC. 9 m . , 31,639 (1941)] has been altered optically and electrically to eliminate certain objectionable features. dcattcred light, dependence of the focus of the plate projection lens upon the aperture of the plate illumination system, photocell fatigue, relatively short life of the projection lamp, and the need for a conbtarit voltage power supply have been eliminated. Plate calibration curves obtained with the altered instrument on 11 itle bands and narrow lines are ewentially identical.
,
i*heniical fartors and a table aiininiariring the reagent8 according to the element or ion determined. The theoretical material is well organized. T h e discussions of deparations and t h e quantitative treatmeat of the equilibria make this a desirable text for advanced classroom use. Many of the procedures are supported b y the author's own observations. He frequently points out the need for research in undeveloped areay. The author is obviously well informed on his subjwt and has supported his information with more than 600 refereiirrs. The literature is said to be complete up t o early 1946. N o errors of fact were detected, although a few accidental errora of *pelling were observed. This hook is strongly recommended for advanced classroom use and should he invaluable t o the industrial and research chemist. WILLIAMM ~ ~ N E L - I N
Symposium on Analytical Chemistry
+
Methods of Vitamin Determination. B. Conner Johnson. iv 109 pages. Burgess Publishing Co., 426 South Sixth St., Minneapolis, Minn. Price, $3.00.
In this laboratory rtianual t h e author has brought under one cover a detailed outline of t h e methods used for determining t h e vitamins. some vitamin metabolites, and amino acids t h a t are important in human and animal nutrition. I n many instances t h e chemical, microbiological, and biological procedures are presented. It is apparrut t h a t t h e author has had considerable experience with t h e methods both in t h e laboratory and in t h e classroom. T h e author intended the manual as a supplement t o lecturer on t h r various methods; therefore it is understandable t h a t in many instances there is a dearth of discussion material t h a t would, in many Cabes. he of value t o one just becoming acquainted with t h e methuds who is confronted with some of t h e problems and idiosyncrasies that arise. Although t h e method of choice or preference is generally d a t e d . t h e reader is not given a n y basis on which he can decide t h e best method for his particular problem. However, sufficient references are made t o original articles so t h a t t h e inquisitive can readily seek t h e knowledge of t h e experienced. T h e manual should be particularly valuable t o persons engaged in teaching biochemical procedures, t o students of t h e biological sciences, and t o nutritionists, for i t provides a readily available compoaite of t h e important, assay procedures.
The Symposium on Uodern Methods of Analytical Cheniisti y is to be held a t the Louisiana State University, Baton Rouge, La., . from March 2 to 5 , 1949. Registration will begin a t 9 4 . ~ on Wednesday, March 2, at the Chemistry Building. The technical program Rill start a t 1 P.M., following a welcoming address b\ Dean -4.R. Choppin. Each speaker will be allowed a minimuni of one hour and time mll be provided for round-table discursinn5
J , HEYROVSKIT.Polarography OTTO H. hfuLLER. Applied Polarography S . H. FURMAN.Potentiometric Titrations High-Frequency Oscillator FRLDJENSEN. H. A. FREDIANI. Microchemical Control Methods HARVEYDIEHL. Electrochemical rlnalysis with C Xa~d d Cathode Potential Control H H. WILLARD. Analytical Chemistry, Pathfinder of Progrt". (banquet address) \T ~ L T E RJ. MURPHY. Trends in Analytical Chemistrl It. I3 )WLING BARNES. Infrared Spectromctry 4 0 BECKVAN.Flame Spectrophotometry d l-: Q. ASHLEY. Some Potentialities of Electroanaly4q
'I'ht, symposium comes the day after Mardi Gras and i t has twen possible to secure a limited number of rooms for February 28 anti .\Iarc-h 1, so that those who are interested may attend the Sew 01.leans carnival. Reservations should be made as early as possible, eqecially by those who wish to attend the Mardi Gras. ,411 rtquvsts for reservations should be addressed to Philip W., \I't-t, Coates Chemical Lahoratory, Louisiana State University. LAWRENCE E. CARPEXTEH Baton Rougc. 3, La. Prrsent plans call for Friday afternoon to be devoted to plant Organic Reagents Used i n Gravimetric a n d Volumetric Analysis. t r i p and golf. The banquet, will be held Friday evening, and on John F . Flagg. xiv 300 pages. Interscience Publishers, Inc , Saturday afternoon following the address by Dr. Heyrovskg 215 Fourth Ave., New York 3, N. Y . ,1948. Price, $6.00. clemonstration.iwill be featured.
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This book, which is Volume IV of a series on chemical analysis, is limited to organic reagents useful in gravimetric and volumetricanalysis. T h e application of organic reagents to colorimetric analysis has already been covered b y Sandell in Volume I11 of this seriea and by Feigl. This book is divided into two sections. I n the first five chapters the theoretical aspects are discussed. Separations, especially those depending on solubility, are discussed in detail in a modern way. T h e remaining fourteen chapters describe specific uses for the common organic reagents, and include tests for most cations and several anions. The book ronrludes with a table of drying temperatures and
Fourth Annual Analytioal Symposium. Hotel WiHiam Penn. Pittsburgh, Pa., January 20, and 21, 1949. Second Symposium on Analytical Chemistry. Louisiana State University, Baton Rouge, La., March 2 to 5 , 1949. Second Annual Summer Symposium on Analytical Chemistry. Wedeyan University, Middletown, Conn., June 1949.
