V O L U M E 26, NO. 10, O C T O B E R 1 9 5 4 Axial Ratio. a :b : c = 2.444:l: 1.355.Interfacial Angles (Polar). 011 A 011 = 73" 52', projection of o i l A 011on 100 = 107" io'. 210 A 210 = 79' 38'. Beta An& 101': 100' ( I ) . ' Cleavage Parallei t o b. X-RAY DIFFRACTION DATA CellDimensions. a = 18.50A.; b = 7.57A.; c = 10.26A. a = 18.74 A.; b = 7.59 -4.; c = 10.36 A. ( 1 ) . Formula Weights per Cell. 4 (4.02 calculated from x-ray data). Formula Weight. 326.39 (328.4 calculated from x-ray data). Density. 1.546 (flotation in carbon tetrachloride-benzene); 1.537 (x-rav). (See Table I . ) \
OPTICAL
MEETING REPORT
,
PROPERTIES
Refractive Indices (5893 A.; 25" C.). CY = 1.644 i. 0.001; y = 1.708 i 0.001; p' (in 100) = 1.655 f 0.001. Optic Axial Angles (5893 A.; 25' C.). 2V = ( + ) 5 3 " calculated from CY, 4, and y. 2 E = 90". Dispersion. Little or none. Optic hxial Plane. . l 010; 67" from c in obtuse 8. Acute Bisectrix. -1 = b. Extinction. p A c = 23" in acute p aMolecular Refraction ( R )(5893 -1.;25' (3.). d a p r = 1.670. R (calcd.) = 76.0; R (obsd.) = 78.9. FUSION DATA. Gliotoxin melts with decomposition at teniperatures from 191" t o 218" C., depending on the heating rate. T h e highest melting point is obtained b y instantaneous melting on a melting point bar. S o crystallization occurs on cooling of the melt.
p = 1.658 f 0.001;
ACKNOWLEDGMENT
T h e sample of gliotoxin used in this study, amounting to 2.5 mg., was obtained from John R. Johnson of Cornell Vniversity. The x-ray powder d a t a were determined b y Irene Corvin of the -4rmour Research Foundation. LITERATURE CITED
(1) Crowfoot, D., and Rogers-Low, B. W., Nature, 153, 651 (1944).
(2) Johnson, J. R., Bruce, W. F., and Dutcher, J. D , J. A m . Chem. SOC.,65, 2005 (1943). (3) Johnson, J R , and Buchanan, J. B., Zbid., 75, 2103 (1953). COKTRIBUTIONS of crystallographic data for this section should be sent t o Walter C. McCrone, Analytical Section, Armour Research Foundation of Illinois Institute of Technology, Chicago 16, Ill.
CORRESPONDENCE Flame Photometric Determination of Calcium i n Wet-Process Phosphoric Acid SIR: Our article [AXAL.CHEZI., 26, 1060-1 (1954)l contained a statement t h a t iron in its usual concentration in wet-process
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Ottawa Symposium on Applied Spectroscopy was TheldFirst at the Physical Metallurgy Research Laboratories, HE
Mines Branch, Ottawa, Ontario, Canada, September 20 and 21. Abstracts of the papers presented are given here. Current Sources and Controllers for the Direct Arc. G. H. FETTERLEY,Norton Co., Niagara Falls, Ont. A 5- to 15-ampere direct current arc is commonly used as an excitation source in the spectroscopic analysis of slags and other refractory materials. An economical way to obtain direct current from a threephase alternating current was discussed: also three ways to control the current automatically. An integrated system of current source and controller that has been in successful use for several years was described. Jaco Ebert Spectrograph and Order Sorter. R. F. JARRELL, Jarrell-Ash Co., Newtonville, Mass., and J. F. GURNEY,Technical Service Laboratories, Toronto, Ont. A versatile grating mounting makes it possible for the spectrograph to operate in any order from the first to extremely high orders. An optical arrangement for separating the different orders was described. Combined Optical Comparator and Scanner with Dual Trace Cathode-Ray Display. R. F. STURROCK, Mines Branch, Ottawa, Ont. An instrument for the comparison of spectra has been designed to combine the advantages of a simple optical display with those of a corresponding cathode-ray display. Optical comparison is made by means of a projection system which focuses an enlarged image of the spectra on a ground-glass screen facing the operator. A section of each spectrum is also scanned photoelectrically and presented in the form of a trace of relative transmittance v8. wave length on the face of a 12-inch cathode-ray tube adjacent to the ground-glass screen. The scanning mechanism, which is of the vibrating mirror type, is so arranged that it is possible to observe the projected image on the screen at the same time. In this respect, as well as in the dual nature of the scanning, this instrument differs from previous spectrum scanning units. At the present stage of development, it is capable of being used for the improved detection of very faint spectral lines in complex spectra and for very close determinations of wave length. The machine is also intended for high-speed quantitative measurements. Multiple Matrix Analysis on the Direct-Reading Spectrometer. J. H. JURMAIN, Baird Associates, Inc., Cambridge, Mass. The direct reading spectrometer can be used for analysis of multiple matrix material, for concentration ranges from impurity levels t o high concentrations of alloying elements, and the switching arrangement used to maintain proper working voltages for elementa used both as unknown and internal standards. The flexibility and limitations of direct readers were described. Spectrographic Studies of Nova Scotia Coals. J. E. HAWLEY AND Y. RIMS.4ITE. Queen's University, Kingston, Ont.
Spectrographic studies have been completed on over 180 samples of nine major seams of the Sydney coal field after ashing a t 400' C. Spectrographic conditions involved the use of a high voltage spark discharge on pellets with rhodium as an external standard. Quantitative analyses were made for 14 elements-vanadium, chromium, manganese, cobalt, nickel, molybdenum, lead, zinc, tin, arsenic, beryllium, barium, strontium, and boron-and intensity ratios were determined for 13 to 14 others, including the major constituents. Samples included blocks of coal of each seam previously classified into petrographic intervals by P. A. Hacquebard, and the results thus allow not only determination of the weighted averagjs of the coal at each sample locality but the average for each seam sampled at several places and the variations from interval to interval both horizontally and vertically. The average composition of all seams studied indicates the coals are relatively enriched in manganese, arsenic, and lead, compared with other "rich" coals, are slightly above the average in zinc but are lower in beryllium, boron, vanadium chromium, cobalt, nickel, and J. A. BRABSON molybdenum. They aho have a relatively high content of strontium W. D. W~LHIDE and barium.
phosphoric acid did not interfere in the flame photometric determination of the calcium. An evidence of considerable interest in other applications of the method, particularly in the biochemical fields, prompts us t o add a word of caution about higher concentrations of iron. .4. RIayer of Magnesium Elektron, Ltd., reports the i n d e pendent development of a similar method for determining calcium in magnesite and calls attention t o a n additive error t h a t results from iron in higher concentrations. We find t h a t the error introduced b y 50 mg. of ferric oxide per 100 nil. of solution analyzed is equivalent t o 1 mg. of calcium oxide. T h e effect of the iron is linear, and a determination of the iron content provides the basis for a correction. Tennessee Valley Authority Wilson Dam, Ala.
1663
1664 Analyses of the seams show some distinctive differences, which, if corroborated by further sampling, could be used for correlation purposes. Such a correlation, however, is complicated by the irregular lateral variation determined in three seams, the Backpit, Harbour, and Phalen. Variations in composition of petrographic intervals support the petrographic classification and show peculiar concentrations of manganese, arsenic, lead and germanium, particularly, in either the top or bottom intervals, and frequently of cobalt and nickel. Three specific correlation problems were considered on the basis of trace element composition-the relation of the Blackrock to the Backpit seams, the Lower Jubilee t o the lower Phalen, and the Gardiner to the Mullins. On the whole, the trace element evidence is not sufficiently decisive to establish the relations clearly. Data on the germanium content of the individual seams and overall average were included. The average germanium content of all seams is 0.004%. The content of individual intervals ranges from a trace to over 0.20%, but no great thicknesses of germanium-rich coals have been found. Spectrographic Analysis of Silicate and Carbonate Rocks and Minerals. G R A H ~MACDONALD M ASD J. E. HAWLEY, Queen’s University, Kingston, Ont. A technique was described for the analysis of silicate and carbonate rocks and minerals using a Stallwood air jet and a 6-ampere direct current arc. Standards used in establishing this procedure include the well-analyzed granite and diabase prepared by the United States Geological Survey (U. S. Geol. Survey, Bull. 980), and National Bureau of Btandards samples ranging from glasses, refractories, and clays to limestone and dolomite. The following ranges have been covered and are considered adequate for most geological problems: A1201 4-40ojO‘ TiOn 0.25-1.0%. FeO 1.0-10%; MgO 0.3-30%: MnO O . O l - O . ~ % ; CaO 0.3-40d; NazO 1.0-10%; KzO 4.0-15%
The sample is mixed with strontium carbonate and buffer graphite: one of sample, one of strontium carbonate, and two of graphite. Strontium is used as an external standard, Sr 2931.8 being used for all elements but sodium with which Sr 3366.3 is paired. Comparisons of results with and without the air jet were given and the great improvement in precision and accuracy evolving from the use of the air jet was illustrated. Favorable comparisons were made with the chemical data on precision as reported in by the Geological Survey. Mention was made of systematic and, a t times, periodic variations in ratios obtained using nickel, palladium, and strontium as external standards, from which data parallel working curves can be drawn. In the course of the investigation an apparent connection was noted between these erratic ratios and the expected ratios. This has been evaluated approximately and used as a correction factor. With this factor or a multiple of it, it is possible to correct the erratic ratios and bring them to a 45’ curve. The phenomena appear due to what Strock has described as “collisions of the second kind.” Use of the air jet almost completely eliminates this effect.
ANALYTICAL CHEMISTRY necessary for analysis of refinery production samples. Samples are mixed with graphite powder and pressed into pellets. Excitation is provided by either high-voltage spark or direct current arc discharges as required for adequate sensitivity. Direct or Nonashing Technique for the Spectrographic Analysis of Used Lubricating Oil. DONALD JACKSON, Canadian National Railways, Montreal, P. Q.
A direct technique for the spectrographic analysis of used lubricating oil was described. A rotating graphite disk electrode carries oil into the analytical gap of a tandem gap alternating-current spark unit of the Wolfe and Enns type. The method is used to determine trace amounts of metals in the oil. Relationship between Applications and Methods in the Spectrochemical Determination of Aluminum in Steel. JOHN H. KELLY, The Steel Co. of Canada, Ltd., Hamilton, Ont. Aluminum controls such steel properties as grain growth, yield strength, inclusion type and content, porosity, notch sensitivity, and transition temperature from ductile to brittle fracture. These properties depend on how much aluminum is present in the steel as each of the three principal components-solid solution, alumina, and aluminum nitride. Gravimetric and volumetric methods of analysis are tedious and time-consuming because of the separation of other interfering elements. Direct spectrographic analysis of solid samples gives only total aluminum and the accuracy is dependent on the proportioning of the three components. A spectrochemical solution method is proposed which involves the separation of the solid solution plus aluminum nitride from the alumina. The solutions are sparked while being absorbed into a porous-graphite electrode. This technique eliminates the delay of gravimetric separations of interfering elements and for certain steels will improve the accuracy of analysis over that attainable by gravimetric analysis. Calibration is based on synthetic standards, covering approximately 0.001 to 0.500% aluminum. During the process of making steel, a knowledge of the degree of oxidation can be obtained by taking an aluminum-killed bomb sample. The analysis of the bomb sample for alumina gives proportionately the oxygen dissolved in the steel at the time the sample was taken. Determination of Barium in Silicate Rocks. Master University, Hamilton, Ont.
D. M. SHAW,Mc-
A direct current arc spectrographic method for the determination of barium was developed. A 10-mg. sample w&s burnt in a l/c-inch platform electrode at a current of 8 amperes, taking 70 to 90 seconds for the complete burn. The discharge was recorded on Eastman Kodak plates Type 111-F, using a Jarrell-Ash 21-foot grating spectrograph with a 5-step rotating sector and a 20-micron slit. The ARL densitometer was used to measure line intensities, and a calculating board to obtain figures for emitted-light intensities, relative to an arbitrary level. Lanthanum was used as internal standard, and the Semiquantitative and Quantitative Spectrographic Analysis Using following lines were measured: Ba 4934; La 4921. An iron-arc w& the Stallwood Air Jet Source. F. -1.LARQ AXD R. F. STURROCK, exposed on each plate and the line Fe 4920 used for calibrations. Mines Branch, Ottawa, Ont. The chief point of interest is a matrix-effect discovered while comparing various artificial standards with rocks to be analyzed. The A spectrographic method applicable to the semiquantitative or latter were shales consisting mostly of silica and alumina, with smaller quantitative analysis of a large variety of samples of widely differing amounts of potassium oxide, ferric oxide, etc. Artificial standards composition was described. A modified version of the air jet first deconsisting chiefly of silica, alumina and potassium chloride (with signed by Stallwood [Stallwood, B. J., J. O p t . SOC.Amer., 44, 171 barium carbonate) were prepared, and mixed with 100% graphite and (1954)l is used along with a spectroscopic buffer and the direct 0.5% lanthanum oxide before burning. The intensity of the lancurrent arc. The model used differs from the original in such a way thanum lines was much less than with a natural rock, prepared in a as to increase the practicability of its construction and use as well as similar way. The addition of 5% ferric oxide to the standard was the repeatability of the spectra. A detailed description of the design found to remedy this effect. The iron oxide does not appear to inand application of the air jet was given, along with a representafluence the barium line. tive group of analytical curves to indicate the results obtainable. The Both standards and natural samples were sintered at red heat for 15 method has been used in the Mines Branch SpectrographicLaboratory minutes after loading the electrodes, to render both kinds of mafor over two years with considerable satisfaction. terials as similar as possible in crystalline state, thereby decreasing systematic errors. Samples were run in quadruplicate, giving a precision of about *20% of the absolute amount of barium for a 95% Spectrochemical Analysis of Redned Rhodium. C. L. LEWIS.4ND probability range. Systematic error was believed to be negligible and W. L. O m , Falconbridge Nickel Mines, Ltd., Richvale, Ont., AND was confirmed by comparison of 5pec-trographir with chemical rewlts J. E. HAWLEY,Queen’s University, Kingston, Ont. carried out elsewhere. Techniques for spectrographic determination of minor constituents in refined rhodium were described. These involve preparation of spectrographic standards in both sponge and black forms and conversion of refinery samples to the same forms for analysis. Principal contaminants are: iridium, palladium, iron, nickel, and silica, but platinum, ruthenium, gold, silver, copper, tin, lead, zinc, and cobalt may also be present. The ranges of concentrations covered are those
Determination of the Origin of Opium by Means of the Composition of the Ash. J. C. BARTLET .IND C . G. FARMILO, Food and Drug Laboratories, Ottawa, Ont. Much of the illicit narcotic trade of the world is concerned with opium. It is not only used as is, but is the source of morphine and the
V O L U M E 26, NO. 10, O C T O B E R 1 9 5 4 indirect source of heroin. In order to control the international drug traffic, the geographical source of illicit opium must be known, so that supplies of the drug may be cut off a t the start. In the past few years, the United Nations Secretariat has acted as coordinator for research aimed a t devising chemical and physical means of identifying the origin of opium. As a part of this program, the composition of the ash of over 100 opium samples of known origin has been determined flame photometrically, spectrographically, and chemically. From the data collected it has been possible to deduce criteria for the determination of the geographical origin of unknown samples. These criteria have been tested by the determination of the origin of 20 “unknown” samples. The validity of the method is demonstrated by the fact that each of the 20 unknowns was identified correctly. Spectrograph in Forensic Science. D. ALAN EAGLESON, The Attorney-General’s Laboratory, Toronto, Ont. This paper discussed generally the type of problem encountered in a laboratory at the disposal of law enforcement agencies, the type of sample submitted as material which may yield readily to spectrochemical treatment, and the use of such analytical findings-for example, in toxicological analyses in sudden death cases due to heavy metal poisoning-as evidence in court. Some qualitative and quantitative data were shown.
1665 Techniques of preparation of standards, loading of electrodes, igniting of sample, and handling of photographic plates were described. Details of the calibration of the plates and the use of internal standards were given. Limits of detection, reproducibility, and accuracy were discussed. Slides showing some details of equipment used and spectra of some of the less familiar and artificial elements were included. Spectrochemical Analysis of Gold Assay Residues Using the Copper Spark Technique. GEORGE M. GORDON, University of Califoi nia, Berkeley, Calif. A technique was described permitting one t o examine fire assay gold residues for evidence of the platinum group metals. The gold is dissolved and analyzed by the copper spark technique, using gold as an internal standard. The smallest quantities of the platinum metals which can be detected in 50 y of gold are: rhodium 0.01 y ; platinum 0.05 y ; and palladium 0.05 y. -4n initial sample weight of 0.1 to 1 mg. of gold is adequate for the determinatons. Spectrographic Analysis Studies of Agricultural and Related Materials in Nova Scotia. F.11.1. LANGILLE. Department of Agriculture and Marketing, Truro, N. S.
The variety of materials analyzed in the spectrographic laboratories of the Nova Scotia Department of Agriculture and Marketing were outlined. Various methods used for wet and dry ashing of plant Selection of Homologous Spectral Line Pairs. J. K. H C R W ~ T Z , tissue and biological tissue samples were discussed. Reasons were Mines Branch, Ottawa, Ont. given for the selection of certain of these methods. A concentration procedure for precipitating and concentrating the trace elements The requirement that the relative intensities of the spectral lines under study was given. The elements studied particularly include chosen for spectrochemistry be independent of source fluctuations was cobalt, molybdenum, nickel, zinc, and copper. Problems and difstated explicitly in the definition of a “homologous spectral line ficulties in the entire analysis procedure were discussed and the pair.” However, implicit in this definition were two additional rechanges that seem to improve the methods were given. quirements that neither spectral line was self-absorbed and that the elements concerned were volatilized at the same rates. The first two conditions were examined in detail for the analysis of steel alloya. Nonmetallic Fluorescent X-Ray Analysis. J. W. KEMP. ~ N DGEO. To overcome the effects of source fluctuations, spectral lines of .kNDERYAXN, Applied Research Laboratories, Glendale, Calif. similar excitation potentials were selected and were found t o be The analysis for major constituents in ores, slags, and related masatisfactory in this respect. Self-absorption was reduced or eliminated in three ways. Spectral lines whose transitions ended on energy terials has always been a difficult problem for spectroscopists. Fair levels which were not near the ground state of the atom or ion conresults have been obtained by techniques involving fusion, hriquetcerned were selected. An air blast was directed across the analytical ting, and optical emission analysis of the briquet. Often, however, this technique does not give sufficient preciqion and accuracy for the gap and away from the spectrograph’s slit to sweep away the absorbing atoms or ions. Suitable excitation conditions were chosen in determination of major metallic constituents, or is too time-consumwhich no absorption was observed for the concentrations involved. ing. Where maximum accuracy is not required, a fluorescent x-ray technique requiring only grinding and sieving the sample will often provide the required analysis. The analysis of several types of material by this method was discussed. Methods of Statistical Inference for the Physical Scientist. It. C. For certain types of samples, and for maximum accuracy, the SHNAY,Mines Branch, Ottawa, Ont. straight powder technique is not satisfactory. A technique consisting The methods of statistical inference were originally developed for of fusion and x-ray analyhis of the resultant head has been dethe analysis of agricultural and biological research data. However, veloped as a solution to this problem. Examples of this method were in recent years these methods have become almost universally recogalso presented. Where required, the bead, after x-ray analysis, can be nized as a powerful tool for the research worker in any field. The used to prepare a briquet for optiral emission analysis, methods discussed include the standard tests of significance, correlation, regression, and the analysis of variance. In every case the underlying absumption and the limitation of these methods were discussed. In some cases the assumptions underlying the standard tests of significance are not valid. Suitable nonparametric or distributionfree methods were described. Correlation analysis of variance and tests of zignificance for ranked data were also discussed. HE Sixteenth Midwest Regional Meeting of the AMERICAN CHEMICAL SOCIETY will be held in Omaha, Neb., November Spectrochemical Determination of Uranium and Thorium in Low 4 t o 6. Analytical papers will be presented in two sessions, on Grade Ores. J. E. BURGENER, J. F. GURNEY,AND N. RUDNIK, Friday afternoon and Saturday morning. Harvey Diehl, Iowa Technical Service Laboratories, Toronto, Ont. State College, Ames, Iowa, served as program chairman for -4 spectrochemical method of analysis was described for the simulanalytical chemistry. rlbstracts of the papers are given here. taneous determination of uranium and thorium in the range 0.03 to 0.8%. Enhancement of the uranium spectrum is achieved by the use of lead and palladium chlorides; chromium is used as an added interImportance of Technical Service Laboratories to Research Organnal standard. izations. WILLIAMT. BUCKINGHAM. Ohio State University, Columbus 10, Ohio.
Midwest Regional Meeting
T
Spectrochemical Analysis of Radioactive Materials. Atomic Energy of Canada Ltd., Chalk River, Ont.
G. ZOTOV,
Procedures developed for the spectrographic analysis of radioactive materials a t atomic Energy of Canada, Ltd., were described. Samples are loaded directly onto graphite, thus eliminating lengthy sample preparations. The electrodes are then mounted in a new type of chamber, especially designed to eliminate radioactive contamination, and are sparked under carefully controlled conditions. The photographic plates are developed and compared with standard plates to give the required analysis.
Proper technical service support has the potentialities to increase greatly the productivity of present-day research programs. Technical service centers are the means by which research can become as productive as possible in increasing fundamental knowledge in science. The technical service center has as its function the provision of a planned. program of technical service support to basic and applied research. Depending upon the size and diversity of the organization which it supports, it may number from 1 to 30 individual sections, such as chemical analysis, the most often requested type of service, spectrographic, x-ray, diffraction, etc. The analytical chemist’s is a
