1391
V O L U M E 26, NO. 8, A U G U S T 1 9 5 4 Or~~rcar, PROPERTIZS Itefract,ive Indices. $ = 1.755 =k 0.005.
y
[58W .\.; 25' C'.). = 1.817 3= 0.005.
O(
=
1.513 =k 0.002.
and of surface contaminat,ions given by these studies were discussed. Typical spectrograms were shown.
Optic .kxial Angles (5893 25" C'.). 2H0= ( - ) 5 6 " . 2V = ( - )48" (cplculated from p a n d 2H); 2 E = !I0 . 1)ispersion. T > v, strong. Optic Axial Plane. 010. Kxtinction. 01 A c = 13' i n oI)tusts 3 . 11olecular Refraction ( R ) [589:3 -1;;-25' C.!,). = 1.890. R(ca1cd.) = 54.1; R(obsd.) = 03.1. F C ~ I OD'4TA. N l,5-dinitronaphthalene sublime:: easily in t h e Kofler block t o give characteristic plates lying on t h e clinopinacoid (Figure 1). On further heating, melting occurs a t 216-217" C. The melt does n o t supercool more t h a n a few degyres a n d crystallization is very rapid. Using oil immersion, many crystals grown f r o m t h e melt show opt'ic axis a n d even H 4 n figures with 2H = ( -)56", r > z' strong [Figure 2).
Sensitivity of Detection of Deuterium Oxide by Infrared Absorption Spectroscopy. W. A . PATTERSON. This paper describes some preliminary experiments on the detection of heavy water in ordinary water, using t h e Baird Associates infrared spectrophotometer. Using 0.5-mm. calcium fluoride cells, t h e differential method of infrared analysis. a reversed cell technique, and nTide fixed slits, deuterium a s a n additive in water can be readily detected in percentages Under presaslow as 0.01% with a probable precision of i O . O O l % . e n t conditions a n ultimate sensitivity of 0.003% deuterium oxide seems probable. T h e determination of ultimate sensitivity has been restricted by bad scattered light conditions when spectrophotometric* slits are widened. If this scattered light problem can be solved, a n ultimate sensitivity of 0.001% deuterium oxide does not seem out of t h e way.
ACKNOWLEDGMENT
Importance of Collision Process in Spectrochemical Analysis. LESTERW. STROCK, Sylvania Electric Products, Inc., Bayside, L. I., N. Y. T h e departure of calibration curve slopes from unity has been interpreted a s due to excitation energy exchange on collisions between atoms in different states of excitation. T h e extent t o which t h e Ijhenomenon affects spectrochemical results was illustrated by typical hut actual calibration curves based on synthetic silicate standards. T h e critical role of a varying sample matrix was pointed o u t . . i n a t t e m p t was made t o account for t h e effect of t h e collision process in t h e intensity equation.
a,;
gas
.\lucli of t h e work described : h o v e was performed untlei, :I contract between Cornel1 University arid t h e Office of Scientific Herearch a n d Development during World War 11. Alfred T. Uloniquist was technical represent3 tive of OSRD Section R-2-.1 supervising progress of this work. CONTRIBWIONSof crystallographic d a t a f u r this section should be sent t u Walter C. MoCrone, Analytical Section, Arnioiir Research Foundation of I!linois Institlite of Technology, Chicago 16, Ill.
MEETING REPORT
Society for Applied Spectroscopy HE
Society for Bpplied Spectroscopy held its ninth annual meeting in New Pork, M a y 27 a n d 28. I n addition t o ail exhibit of spectroscopic instruments, a group of papers on the theme of "Frontiers in Spectroscopy" n-as presented. Isotope Analysis by Emission Spectroscopy. J . R. McN.\I.LY,JR., Oak Ridge National Laboratory, Oak Ridge, Tenn. This pager covers applications of high resolution spectroscopy t o t h e determination of i3otropic concentrations in materials. Material was presented on the source and instrumental problems associated with this field of analy and illustrations were given of the preci-;ion ohtainable and t h e future potentialit,ies in this field. An R F Linear Decelerator Spectrometer. WALTDOXNER. Mass Spectrometry Research, Beckmsn Instruments, Inc., Fullerton, Calif. - i n R F linear decelerator mass spectrometer was described, featuring resolution to 100 and a dynamic range of 2000 t o 1. Ions are formed by electron impact in a somewhat conventional ion chamber, utilizing a n electron beam a t right angles t o t h e ion beam, temperature regulation, and pressure differential for high signal t o background ratio. All of t h e ions are then accelerated through 2500 volts, collimated, and then passed through a series of 34 RF gaps, spaced such t h a t t h e preferred (or resonant) particles are decelerated hy a n amount equal to t h e peak R F voltage a t each gap. all other particles emitting from t h e R F analyzer with correspondingly higher energies. T h e resultant "energy dispersed" beam is then separatrd in a n electrostatic deflection system, t h e preferred (lowest energy) beam being collected in a Faraday bucket, and observed on a vibrating reed electrometer. -4linear mass scan is achieved by varying t h e frequency applied t o t h e gaps. Typical mass spectra and stability figures were given. Reflection of Infrared Radiation from Free Liquid Surfaces.
E.
D. MCALISTER, Eastman Kodak Co., Rochester, N. Y. Simple modifications of a conimercially available douhle-beam spectrophotometer employing a sodium chloride prism provide full scale readings for 5 or 10% reflection with signal t o noise ratios of about 100 t o 1. This expedient enables detailed study of the anomalies in reflectivity corresponding to regicns of high absorption Coefficient even though t h e reflectivity is only 1 or 2%. T h e possibility of measuring t h e absorption coefficient (when large enough t o cause a n appreciable anomaly in reflection) by measuring the reflectivity for two different angles of incidence was discussed. Some suggestions concerning t h e nature of surface layers of molecules
New Multichannel Direct-Reading Spectrograph. FREDERICK BRECH,FRED4. AICNALLY, AND LORENP. NEAL,Jarrell-Ash Research Laboratory. A multichannel direct-reading spectrograph based on t h e Wadsworth mount was described. Spectra are displayed on two levels on each of which several fixed position exit slits and photomultipliers may be located. B y this arrangement, two det,ector tubes m a y be sited on two lines with a small wave-length separation without t h e use of optical separator elements. With t h e circuits employed, t h e signal from each photomultiplier is converted t o fixed amplitude pulses whose frequency is proportional t o the signal strength. T h e working curve for each channel is displayed on a separate dial face t h e rotation of which from a fiduciary position may be employed when necessary to compensate for a shift of the working curve. Details of t h e instrument and samp!e analyses performed with it were discussed. Raman Spectrometer Assembled from Available Components.
S. M. DAVIS,R . F. STAMM, G. L. ROYER,AND H. C. LAWRENCE. American Cyanamid Co., Round Brook, N. J. A photoelectric Raman recording spectrometer has been assembled from commercially available optical and electrical components. T h e light source is a Toronto-type mercury arc supplied by hpplied Research Laboratories. T h e arc controls and housing were built in our shop. T h e sample tubes, filter jarket, and condensing lens system h a r e been deicribed by one of t h e authors. T h e monochromator started with a Perkin-Elmer Model 12 spertrometer equipped with a 60' light flint glaw prism and off-axis parabola. T h e standard Littrow mirror was replaced by a plane diffraction grating nThose dispersion aiirments t!iat of the pri.cm. T h e slits were modified t o correct f o r the cauri-ature caused by the prism. An RCA 1-P-21 photomultiplier was mounted inside t h e monochromator directly behind t h e exit slits. T h e standard Perkin-Elmer 13-cycle chopper and Model 81 amplifier modified t o have 1-, 2-, 5-, and 12second time constantswere used. T h e output from this is recorded on a standard L & N Speedomax rrcorder whirh had been modified with an automatic range changing device supplied by Karren Electronics. Some performance data were giren. Progress of the X-Ray Spectrograph. . BEHR,North American Philips Co., Inc. T h e advent of t h e x-ray spectrograph into the analytical field is not new. T h e method -cas thoroughly studied and widely applied a generation ago. However, t h e inatrument has been commercially available for only a few years. Research and commercial control have found t h e method useful and its acceptance has been rapid. Several hundred units are in use a t t h e present time and there is a rapidly growing wealth of information available touching on such factors a s fields of applicability, techniques, and analyses of d a t a . These points were summarized. T h e future progress of t h e method can be predicted in t h e light of t h e past progress, t h e inherent features, and t h e known lines of instrumentation changes in design and contemplation. There are certain limitations imposed by t h e basic physics involved, and t h e practical limits t h a t these impose are becoming evident.
1392 Analysis of Nonferrous Alloys by the X-Ray Spectrograph. L. CRUXRINE, North American Smelting Co.
ANALYTICAL CHEMISTRY GAR-
TUX
.I brief review of t h e analysis of aluminum-base, copper-base, and lead-tin base alloys was given. T h e methods now in use in production control and comparative results with wet chemical methods were presented. Determination of Metallic Elements in Nonmetallic Matrices. -1.YHURKUS, dpplied Research Laboratories.
A.
T h e determination of metallic elements in nonmetallic matrices has been studied, using both emission spectroscopy and x-ray fluorescence. This paper compared t h e results ohtained using these two supplementary methods. New Spectrophotometer for Use with Volumes of 0.01 to 5 M1. FREDERICK BRECHA N D DAVIDGLICK,Jarrell-Ash Co., Kewtonville, Mass., and Department of Physiological Chemistry, Unirersity of Minnesota, Minneapolis, Minn.
A double-beam instrument was described for use in the ultraviolet and visible regions between approximately 200 and 700 mu. 4 grating monochromator with a reciprocal dispersion of 4.4m u per mm. provides two beams, each focused on a separate exit aperture. One beam passes through a cuvette containing t h e sample and t h e other passes through a reference cell. d rotating alternator permits each beam in turn to fall on t h e same area of a single photomultiplier, the output of which is coupled to a logarithmic amplifier. This provides a signal of the form log B I B which is displayed on a meter graduated linearly with optical density, and also carrying transmission scales. A feature of the instrument is t h a t it employs special cuvettes with a 1-cm. light path having volumes of 0.010-ml. microcuvettes of this type with light paths up to 5 cm. can be accommodated. Macrocuvettes with light paths from 1 to 5 cm. having volumes of several milliliters can also be used. Examples of the use of t h e inbtrument in biochemical and histochemical research were detailed. Applications of the Microvolume Technique to Emission Spectrochemistry and Metallurgy. J. K. HURRITY,Mines Branch, Ottawa, Ontario, Canada. There has been a growing metallurgical interest in segregation of alloying constituents and trace elements in casting and in t h e study of solid-state diffusion phenomena. T o obtain t h e necessary analytical d a t a , a rapid quantitative spectrographic technique has been developed. I n principle, t h e specimen is moved over a spark discharge while the photographic plate is lowered so t h a t each point on t h e spectrum corresponds to t h e analysis of a point on t h e specimen. A theory has been developed which takes into consideration t h e effects of the measurable instrumental variables and predicts quantitatively t h e observed intensity changes in t h e spectrum when a region of rapidly changing composition is traversed. T h e practical significance of thid theory was indicated. Illustrative examples of the analysis of segregates were given, and a n outline of the method to be applied t o specimens in which diffusion has occurred was described. T h e results of a prespark-effect investigation in the spectrochemistry of zincbase alloys indicate a procedure by which this effect may be eliminated. Future developments in the microvolume technique were discussed. Illumination of t h e Spectrograph. R. H . BELL, Lucius Pitkin. Inc. T h e selection of a suitable lens system for t h e illumination of the spectrograph was discussed, particularly in relation to the proper “sampling” of t h e light source and t h e ways in which t h e practical resolving power of t h e spectrograph is affected. Results of tests on the use of ground diffusion screens, and gratings, both transmission and reflection, were presented. It is believed t h a t the proper illumination of the spectrograph should be given much more consideration t h a n it has been given previously. Evacuable Die for the Pressed Potassium Bromide Technique’ HARRYHAUSDORF, T h e Perkin-Elmer Corp., Norwalk, Conn. I n February 1953 a general paper on this invaluable technique was present.ed a t t h e Society for Applied Spectroscopy. Since, t h e author had the opport,unity to compare various types of dies for pressing potassium bromide and sample into thin transparent disks. T h e experience gained during this evaluation period led t o the choice of a design of a special evacuable die which provides optimum results. This die was shown and described. Performance of the Perkin-Elmer Model 2 1 in the Spectral Region V. J. COATER, T. MILLER,A N D A. SAVITZKY, PerkinElmer Corp. T h e Perkin-Elmer Model 21 double-beam recording infrared spectrophotometer employs a completely achromatic optical system. 210 to 2300 mu.
T h e controls provided on this instrument allow t h e operator to vary its operating conditions over a wide range, optimizing its performance for a gireu problem. It might be expected t h a t by the addition of t h e proper sources, prism, and detectors satisfactory performance can be obtained in the ultraviolet, risible, and near infrared portions of the spectrum, without affecting its infrared performance, which now extends to 37.5 microns. On a n experimental basis, a standard instrument has been converted for operation in this region while maintaining its function as an infrared spectrophotometer. T h e design of the various attachments and the problems involved in providing simple interchange were discus.:ed. The performance obtained with this system was shown. Novel Solution Excitation Apparatus for Spectrochemical Analysis Alloys. STCART MILLIM.4N A N D HYMAXKIRTCHIK.Materials Laboratory, Development Department, General Electric Co., Evendale, Ohio. Of
T h e spectrographic analysis of a wide variety of metal alloys in t h e form of fabricated pieces presents sampling problems not easily overcome by normal excitation techniques. Standard points t o plane methods are not practicable when t h e size of finished part samples falls belqw a minimum thickness of mass, causing excess heating of alloys containing large amounts of elements of relatively low therma1 conductivity. Normal segregation in metal products may require repeated determinations or multiple super-imposed exposures to obtain representative sampling. T h e adjustment of excitation parameters to obtain large sparking areas is prevented in many cases b y the small surfaces of samples auch as nuts, bolts, washers, and gasketa. -4separate analytical method for every different size group of aamples i3 an overwhelming task when a quality control program must be msintained for a product containing many parts. T h e common methods used to overcome thebe sampling problems are techniques of solutions, filings, grindings, powder extracts, briquets and pressed solid samples. This laboratory has investigated those of metallic acid solutiond. A novel solution excitation chamber has been devised which maintains a continuous flow of liquid sample to the lower electrode of a standard high voltage spark system. I t supplies a relatively large volume of sample to the analytical gap, providing high sensitivity and adequate reproducibility. The device contains no moving parts, external electrical or air line connections, and is used with a n y standard dual clamp excitation stand a s a normal carbon rod-to-rod sparking technique. There are no critical dimensions required and construction can be finished in a day a t a cost of a few dollars. The method requires t h a t t h e solution be a n electrolyte and its primary disadvantage of incomplete solution for certain elements is common to many solution techniques, although a n unfiltered flow of fine suspensions t o t h e analytical gap is provided. Results of experimental techniques were discussed for t h e analysis of low-alloy steels, stainless steels, and titanium alloys. 50,000 Sources of Excitation. J. T. Rozs.4 National Spectrographic Laboratories, Inc.
AND
0. W. UGUCCINI,
The variety and complexity of spectrographic excitation sources have been steadily increasing during the past decade. Since t h e major consideration is the output a t t h e analytical gap, a method of classification based upon their secondary amperage is suggested for all sources. T h e duration of current flow per half cycle, t h e amplitude of the w a r e form, t h e frequency, and t h e unidirectional aspect afford considerable clarification and enhance the opportunity for standardization of techniques. Applications of t h e Recording Spectrometer to Emission Spectroscopy. FR.4n.K B. GRAY.J R . ,.AND .j‘ICTOR s. L-NDERKOFFLER Leeds & Xorthrup Co.
-4 brief description of the recording spectrometer was given. Representative performance data in the ultraviolet and vi-ible re-. gion were included. T h e following applications were covered : Hydrogen-Deuterium Ratio Determinations. The parameters involved in t h e isotope ratio measurements were discussed as well as the application of this method to problems in t h e medical, biological, and chemical fields. O H atlas for the ultraviolet. Conipilation of an atlas for the complex molecular band spectra of O H in the uItraviolet has been pre-pared by use of this instrument. Emission spectra showing the second positive systems of Nz. Rapid scanning a t 250 A . per minute shows the band heads and a n indication of the bands associated with them. Slow scanning a t 6 A. per minute shows t h e detail within t h e bands themselves. Line intensity comparison in t h e band spectra from flames. This reveals particularly valuable information in evaluating t h e temperatures of hot gases and t h e departure from equilibrium conditione, in t h e combustion regions of flames.
