Second Annual Analytical Svmosium I
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wed by the Analytical Di vision, Pittsburgh Section, American Chem,ical Society L. T. HALLE'I T,Ass,ociate Editor
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bLurv _-._ ___.__ __, fraction spectrometer, Pauling oxygen meter, and high-frequency oscillator titrimeter. Much of current development in analytical chemistry is connected with instrumentation as exemplified in better assembled and coordinated apparstus, adaptation of analytical techniques to automatic analysis,, recording of the analysis, and process control based on andytical data determifled. Typical examples include automatic apparatus for orgamc combustion analysls and the automatic recdrding emission spectrometers. Since the great majority of recent analytical techniques depend upon calibration with the compounds being determined, much attention has been given to the preparation of pure componnds for use as analytical standards, as in the progrsm of the National Bureau df Standards and the American Petroleum Institute for the preparation of pure hydrocarbons. Collections of available data on pure cornpounds include the catalogs of ultraYiolet and infrared absorption spectrograms issued by the National Bureau of Standards and American Petroleum Institute, and of x-ray diffraction data issued by Daw and the A.S.T.M. Linked inseparably to the preprtratiou of pure compounds and to the geueral processes of analytical chemistry are.methods of separation. The newer separation techniques serve essentially the same purpose as the older ones-i.e., the preparation of an item which can be measured free of .interference. There have been outstanding developments in fractional distillstion and in fractional adsorption-.g., chromatography. Newer separation techniques include partition chromatography, countercurrent PHIUPJ. ELVING~ distribution, and the fractional desorption of gaseous mixtures.
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T IS a demonstration of the initiative of the Analytical
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ivlsmn of the Pittsburgh Section of the ACS that it sponsored the second analytical symposium a t the Mellon Institute on March 8. After opening remarks to the one hundred analysts present by J. C. Redmond, chairman of the Division of Analytical Chemistry, and by H. E. Longenecker, chairman of the Pittsburgh Section of the ACS, P. J. Elving gave a survey talk on recent trends in analytical chemistry. The papers were well prepared and presented, and reflected the wide interests of analytical chemists in the Pittsburgh area. The lively informal discussion of things analytical during and after the luncheon among those having mutual problems added to the spirit of genuine scientific interest which characteriaed the meeting. The committee for this symposium, composed of R. G. Russell (Gulf Research), Harry Pfann (Koppers Co.), and C. Manning Davis (Fisher Scientific Co.), deserves credit for a job well done. A. H. Bushey and J. K. Miller, presiding a t the morning and afternoon sessions, respectively, effectively kept the meeting on schedule. An abstract of each paper is given below; if additional details am required by any of our readers, they should write directly to the author.
Recent Trends in Analytical Chemistry. Publicker Industries, he., Philadelphia, Pa. The most significant features in the progress of ?n@yti!d chemistry during the past two decades are discussed as mdIcat1ng not ouly the direction in which analytical chemistry is moving but also the probable direction of fruitful future development. Analytical chemistry is defined as including all means of gathering knowledge regarding the composition and constitution of samples of matter in terms of the kind, quantity, and grouping of atoms. Increasing attention is being paid to the determhation of the structural composition in addition to the elementary composition. Added to the familiar determination of organic functional groups have been techniques such. as x-ray dXractlon and rnirroscorw which enable determination of the actual inorganic and orga& compounds present. The development of small-scale techniqueaemimicro, micro, and ultramicr-has influenced all fields of chemistry; the success of earlv - - ~ research ~ ~ " on the Manhattan Project was due in laree Dart to the use of ultramicrotechniques. Puiddamental research on the bases of analytical chemistry is increasirIg; examples of progrl~msof basic research are those of KoltholB on coprecipitstion and of Mellon on colorimetric methods.
Polarographic Determination of Nickel. Application t o Catalyst Material. R. 0. CLARK, Gulf Research & Development Co., Harmarville, Pa. The polarographic technique was investigated in an effort to speed up control analysis of hyeogenatlon catalysts for nickel. The samples comprised a series of catalysts prepared by multiple impregnation of various support bases, such w . alumina, silics, kieselguhr, et!., with a nickel s d t and calcining to 800" F. D s t s were avdlsble which showed the moisture content of such materials to vary widely. A dryiqg procedure was required, since it was desired to mske a correlation from the nickel contents of the samples. Since the nickel present in the samples varied from 45 to 7570, i t was impefative that a small sample be taken for analysls, and this necesmtated,investigation of a sampling technique compatible wit,h. the requirements of a control procedure. Solution of the metal oxlde deposited on certain catalysts could not be effected by a leaching process; for such material a simDle sealed-tube technique wa5 devised "sine concentrated bydrdehloric acid as a solvent.
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known techni7pes are the advances made during the past five years in irlt,rnvinlet and infrared absorDtion spk&ophotometry and in m a spectrometry, due to the demands of the high-octane gasoline and synthetic rubber programs. Other typical examples are the development of specific orwnic reaeents and the increasing uSe of isotopic tracers. Greater attention is being paid to the application of new methods and techniques. Typical new chemea1 reactions are the Karl Fischer method for the determination of water and the Diels-Alder reaction for oonjugated dienes. Techniques developed during the past two decades include polarography, ion-exchange, specific dispersion, and stati8ticd methods for evaluating analytical results. Analytical i n st r u m e n t s
Symposium Committee. H. F. Pfann, Koppers Co., R. G. Russell, Gulf Research a n d Development Co., and C. M. Davis, Fisher Scientific Co. 284
V O L U M E 19, NO. 4, A P R I L 1 9 4 7 and precision. of the method compare favorably with those obtained by precipitation of the nickel as the dimethylglyoxime salt and electrodeposition as the metal, with an appreciable saving of time. The method is being used a t present with considerable success for the purpose for which it was intended. Phosphoric-Perchloric Acid Oxidation of Manganese. ERNEST BUYOK,Duquesne Torks, Carnegie-Illinois Steel Corp., Duquesne, Pa. A rapid and accurate method for determining manganese in materials of high manganese content was developed and patented by W. D . Brown, chief chemist, Duquesne Works, CarnegicIllinois Steel Corp., based on a statement by Willard and Young, University of Michigan, that manganese is oxidized to Mnz03by perchloric acid in presence of phosphoric acid. Dissolve a suitable sized sample in acid, add perchloric acid and phosphoric acid, oxidize by fuming, cool, add 1 to 1 sulfuric acid, aerate to remove chlorine, add a few drops of silver chloride, and stir to remove the small amount of hydrochloric acid formed during fuming. Dilute, and add an excess of ferrous sulfate. Titrate excess ferrous sulfate with jtandardized potassium permanganate solution.
285 and the presence of undesired carbides, Examples of quantitative studies are shown in studies of solid solution formation in two carbide systems such as tungsten-molybdenum carbide aad tungsten-titanium carbide by quantitative determination of the intensities of the reflections of the various constituents before and after heating. Finally, the quantitative estimation of the changes taking place during the sintering of cemented compositions are illustrated.
Instrumental Curves. C. MANNINQ DAVIS, Development Laboratory, Fisher Scientific Go., Pittsburgh, Pa. There are fundamental factors which alter the ahape, form, and slope of curves obtained from instruments employed in colorimetric analysis, potentiometric titrations, and polarographic analysis. A knowledge and proper control of these factors broaden the field of application and enhance the usefulness of an instrument in the analytical laboratory. Factors other than pH, reagent used color stability, and temperature, which alter the slope of the caiibration curve in colorimetry are: final dilution volume, sample size, sample cell size (length of optical path through the colored solution), and wave length of the light used (filter or filter combination employed). Negative readings, high blanks, adherence to Beer's law, and use Analysis of Certain High-Temperature Alloys. E. W.BEITER, of a factor are other points to consider. Westinghouse Research Laboratory, East Pittsburgh, Pa. I n potentiometric titrations the following factors have been Typical Analysis found to alter the curve obtained from the instrument: amount % % of sample, concentration of titrant, degree of ionization of sample, Ni 34.7 M0 4.90 titrant and product formed, electrodes employed, cleanliness of C" 20 4 Si 0.57 electrodes, temperature, and pH. &In 18.3 0.67 Cr Factors influencing the curve in polarographic analysis are 0.17 AI 17.5 Fe 2.95 Ti dropping rate of the mercury (mass of mercury), supporting electrolyte, maxima suppressor, constancy of the temperature, Samples are dissolved in a mixture of 4 parts of concentrated purity of the mercury, and pH. hydrochloric acid and 1 part of concentrated nitric acid; 25 ml. per gram of sample are used a t room temperature. Emission Spectroscopy in an Oil Industry. R. G. RUSSELL, Cobalt. To 0.4000 gram of sample, add 10 ml. of 1 to 1 sulfuric Gulf Research and Development Co., Harmarville, Pa. acid, evaporate t o slight fumes of sulfuric acid, and dissolve in The paper is of a general nature, correlating the many new 50 ml. of water. Titrate potentiometrically with potassium techniques available for the miscellaneous types of analyses ferricyanide solution. originating in an oil laboratory and contrasting them with the Nickel, Evaporate a 0.5000-gram sample, treated with 10 usual type of spectrographic analysis. ml. of 1 to 1 sulfuric acid, to slight fumes of sulfuric acid. Take There are almost none of the routine type of samples so usual a 0.1000-gram aliquot for analysis. Dilute to 300 ml., and add in routine metallurgical practice. Instead there are nonmetallic 5 grams of citric acid, 10 grams of ammonium chloride, and a catalyst samples, oil additives, oil-field brines, and used oil 5-ml. excess of concentrated ammonium hydroxide. Now add samples, as well as a large variety of other types of samples sent twice the amount of potassium ferricyanide used in the cobalt in for both qualitative and quantitative analysis. A qualitative titration to oxidize the cobalt. Add dimethylglyoxime to solution analysis is turned out within less than one hour for approxia t room temperature, filter on paper after 1 hour, wash with cold mately 70 elements, in which the elements are arranged in their water, dissolve in nitric acid, and reprecipitate and weigh in correct concentration groupings. usual manner. Methods are described for the analysis of alkalies in catalyst Chromium. Oxidize a 0.5000-gram sample with ammonium materials by the use of the alternating current spark. 4 method persulfate and titrate potentiometrically. for the complete analysis of oil-field brines for all the metallic Molybdenum. Take a 1-gram sample, and precipitate constituents is briefly described, and slides are used to indicate molybdenum with a-benzoin oxime. the accuracy of the method. The use of electrodes other than Iron. Separate iron with cupferron in the filtrate from the graphite-i.e. copper-in quantitative analyses is described. molybdenum determination, destroy organic matter, reduce, A method for the identification of thin flms on conducting maand titrate. terials by means of short low-powered exposures is indicated. Titanium. I n a 1-gram sample, determine titanium with p The decreased analysis time of such spectroscopic procedures hydroxypheflyl arsonis acid. over chemical analyses is stressed, but such analyses take much Silicon. T o a 2-gram sample, add 0.5 ml. of 1 to 1 sulfuric longer per determination because of sample preparation and low acid to keep titanium in solution, bake a t 110" C., and determine number of analyses per sample than do similar analyses in routine silicon in the usual way. metallurgical control. Manganese. From a 1-gram sample, remove chromium with mrchloric acid and sodium chloride. Oxidize with ammonium Routine Spectrographic Analysis of Solders and Babbitts. G. persulfate and titrate with sodium arsenite. W. WIENERAND A. W. DANKO,Materials Engineering DeAluminum. From a 1-gram sample, remove elements other partment, Westinghouse Electric Corp., East Pittsburgh, Pa. than titanium by the mercury cathode. Remove titanium by treatment with sodium hydroxlde in a nickel beaker. Precipitate A spark spectrographic method for the analysis of l a d , co aluminum with ammonium hydroxide and weigh as AltOs. antimony, and tin-base solders and babbitts and tin-lead eo?g:A has been developed. The percentage ranges of analysis include Analysis with an &Ray Spectrometer. J. C . REIDMOND, Kennacopper from 0.10 to 7.50%; antimony, 0.10 to 2.50%; lead, metal, Inc., Latrobe, Pa. 0.10 to 2.000/0; and tin in the tin-lead solders, 20.0 to 70.0%. The samples used are disks 1.5 inches in diameter by 0.5 inch, The value to the analyst of x-ray diffraction in revealing with cast in an open steel mold. The sample is used as the upper certainty the state of combination of the elements is discussed. electrode and a 0.5 inch hemispherically tip ed carbon as the While x-ray diffraction is not new, the deyelopment of the lower electrode in a Petrey spark stand. $he tin-base alloys direct-reading Gei er counter spectrometer with its advantages are sparked on either side of the disk while the tin-lead solders of speed and simpficiy of operation now makes i t worth while are sparked on both sides, superimpos!ng the exposures to reduce to consider x-ray diffraction as a routine control instrument the segregation effects. Cop er, antimony, and lead working comparable to the spectrograph in those cases where it is apcurves are plotted in the usuaf fashion of log intensity veem log plicable. Whereas the results of x-ray Mraction analysis concentration. The high-percentage tin is calculated from a by classical photographic methods gave at best semiquantitative graph by plotting log intensity versus 70( P H I ? ) . results, quantitative results with an average reproducibility as The method as developed is rapid and of suitable accuracy good as 1.4% have been obtained in unusual cases, 5% being a for routine control of solders and babbitts. Segregation effects fair average reproducibility. are reduced by the superimposition technique and the tin-lead Typical examples of the use of the instrument in connection difference function ermits the analysis of high-percentage tln with refractory metal carbide studies show its utility in qualiwith an accuracy o? *2.00% of the amount present. tatively detecting impurities such as oxides in tungsten powder, I_
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