ANALYTICAL CHEMISTRY
1854 if the chemical separation of these elements was as sharp and complete as the gravimetric results indicated. The emission spectrograph was used for evaluation of the results because of its complete specificity for each element. Spectrographic procedures previously developed for these elements were not sufficiently sensitive for the determination of very small amounts of platinum and iridium in solution. Two additional spectrographic methods for the determination of platinum and iridium were studied extensively. One of these methods extended the lower limit of determination of platinum t o include solutions of 10 p.p.m.; t h e other method was so sensitive t h a t both elements could be determined in solutions containing only 5 t o 10 y of total platinum or iridium, with a n accuracy within +6%. The latter method is applicable also t o the determination of rhodium and palladium and is even more s e n s i t i ~ efor these two elements. Results showed that the Aeparation was 09.6 t o 99.9% complete. After separation of solutions containing 100 mg. of each element, analysis showed only 0.1 t o 0.2 mg. of platinum had coprecipitated; only 0.1 t o 0.2 mg. each of rhodium and palladium remained in solution, while 0.3 t o 0.4 mp. of iridium failed t o precipitate.
glyoxime in the presence of iV,AV-dihydroxyethylglycine. This reagent prevents the precipitation of ferric hydroxide even a t pH 11 and above. 9 large excess of the reagent (50 grams or more) prevents complete precipitation of the nickel, but this contingency is simply avoided by the addition of zinc chloride, which forms a complex with the excess of the reagent without releasing the iron or interfering with the nickel precipitation.
Simultaneous Spectrophotometric Determination of Iron(I1) and Total Iron with 1,lO-Phenanthroline. AUBREYE. HARVEY, JR., JOHN A. SMART,ASD E D W - ~ RS.D . ~ M I S , University of .hkansas, Fayetteville, Ark.
Satisfactory analytical methods have been worked out for all cations and anions in typical zinc-plating baths except acetic ion. The paper presented a colorimetric method for acetic ion using lanthanum nitrate reagent under carefully controlled experimental conditions. While this method does not give results of high precisions, it is more reliable t h a n other methods which have been reported.
When 1,lO-phenanthroline is added t o a solution containing both iron(I1j and iron(III), a reddish-orange iron(I1) complex and a yellow iron(II1) complex form immediately. The iron(I1j complex has an absorbance maximum a t 512 mp, a t which wave length there is little absorption by the iron(II1) complex. The two complexes have identical absorbance coefficients at 396 mp. A method is presented for the determination of iron(I1) and of total iron in the same solution by simultaneous measurements of absorbance at 396 and 512 mp. The limiting concentrations for interference by 22 cationa and 14 anions are reported. Vanadium(I1) a s a Volumetric Reducing Agent. ERNEST L. MARTIS A N D KENTONC”. BEXTLET.University of Kern Mexico, Albuquerque. X. kl. T-anadiurn(I1) is a strong reducing agent, comparable t o the rhromous ion. However, it i.* difficult t o employ it a s a standard volumetrir solution because of the instability of the reduced solution. Improved procedures for the dtandardization and storage of the reagent are being studied and titration methods employing vanadium(11) are reported. T h e stability of reduced vanadium solutions ander various conditionh has been investigated.
Southeastern Regional Meeting of the T SOCIETY
Southeastern Regional Afeeting h 1 E R I C A S CHEJIICAL wa? held in Birmingham, Ala., October 21 t o 23. T h e program included visits to plants a n d laboratories, a n d a t a l k at breakfast, on F r i d a y morning by XI. G. Mellon, I’urdue University, on “Demanning Analytical Determinations.” Abs t r a c t s of special interest t o analytical chemists are printed here. HE
Determination of Copper by Precipitation with 2-(o-Hydroxyphenyl)-benzoxazole in t h e Presence of Ethylenediaminetetraacetic Acid. J. H. ROBERTSOS.LND E. E. BTRS, University of Tennessee, Knoxville, Tenn. I n a study of the precipitation of metal ions in the presence of chelating agents t o prevent undesired precipitations it was found t h a t the reagent 2-(o-hydroxyphenyl)-benzoxazole is a n excellent precipitant for copper in the presence of a n excess of ethylenediaminetetraacetic acid at p H 10 and above. The method is virtually specific for copper in solutions containing a wide range of foreign ions. The only interferences are those metal ions which precipitate from a n ethylenediaminetetraacetic acid solution a t pH 11 t o 12, and these when present can he separated by filtration before the addition of the reagent. Quantitative Separation of Nickel from Iron and Cobalt by Precipitation with Dimethylglyoxime in the Presence of N,N-DihydroxyA N D E. E. ethylglycine a s a Masking Agent. J. H . ROBERTSON BTRN,University of Tennessee, Knoxville, Tenn. Interference of iron(II1) and pobalt can be avoided and the determination of nickel made quantitative by precipitation with dimethyl-
Determination of Zirconium by the Chloranilic Acid Method. hfENIS, Oak Ridge National Laboratory, Oak Ridge, Tenn.
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The optimum conditions for the estimation of microgram quantities of zirconium as the chloranilic complex have been established. T h e effect of acid concentration, wave length, temperature, and quantity of reagent on the precision of the procedure have been investigated. The tolerance for interfering ions has been determined and procedures for the elimination of some of the most seriously interfering ions, iron(II1) and fluorine, were developed. Determination of Acetic Ion in Zinc-Plating Baths. T . H. WHITEHESRYW.WRIGHT, University of Georgia, Athens, Ga.
HEAD AND
Differential Spectrophotometric Determination of Zirconium. D . A N D J. C. WHITE,Carbide and Carbon Chemicals Co., Oak Ridge, Tenn.
L. ~ T A S S I S G
Differential spectrophotometry has been applied t o the determination of relatively high concentrations of zirconium as the alizarin sulfonate complex in 1.U perchloric acid solutihn. The method is particularly auited for samples where the zirconium concentration is generally known and its precision compares favorably with the best precision obtainable by gravimetric procedures. There are few interference*; fluoride, sulfate, and phosphate are the primary ones. Identification of 3,4-Benzpyrene in Cigarette Paper Smoke and Tars. D. V. LEmimNE, Cancer Institute of Miami, Miami, Fla. T h e smoke and tars produced by the burning of commercial cigarette paper were absorbed in organic solvents. On purification by chromatography, a fraction was obtained with fluorescent and absorption spectra strongly resembling those of 3,4-benzypyrene. Others have obtained similar curves in establishing t h e presence of this polynurlear hydrocarbon in industrial effluents and sewage. Infrared Investigation of the Stereochemistry of Some Bicyclic Lactones. P. WILDER,JR.,ASD A. KINSTOS, Duke University, Durham, N. (’. Five lactones derived from the e m adduct of dimethylfulvene and maleic anhydride and two lactones derived from the e m adduct of pentamethylenefulvene and maleic anhydride have been prepared. Infrared spectra of the compounds have been determined in Nujol mull and carbon tetrachloride solution. The stereochemistry, particularly the size of the lactone rings, was discussed in terms of these spectra. Spectrophotometric Determination of Nickel a s the DimethylA N D C . C. SUSANO, glyoxime Complex. 0. MESIS,M. L. DRUSCHEL, Oak Ridge National Laboratory, Oak Ridge, Tenn. The colorimetric method for the determination of nickel by dimethylglyoxime Tvaa modified t o assure greater precision and accuracy. Potassium persulfate is used as the oxidizing agent. Optimum conditions for p H , wave-length selection, quantity of reagent, tolerance of interfering ions, and time factor have been established. Differential spectrophotometric technique has been applied t o the estimation of nickel in steel sampleb. A critical review of t h e literature presenting the varied and conflicting theories as t o the structure of the complex and the best procedure for determining nickel was given.
Use of Control Charts in Analytical Chemistry. 13. L. hfCCTTCHEN, Oak Ridge Sational Laboratory, Oak Ridge, Tenn. The techniques, terms, and symbols associated with the use of control charts were dibcussed. The interpretations of variations revealed by control charts were presented t o illustrate the use of these charts in controlling the quality of chemical analyses. The detection of gross errors and biases, and the significance of trends were also given consideration.
V O L U M E 26, N O . 11, N O V E M B E R 1 9 5 4 A Precise Volumetric Determination of Fluoride. J. hi. C'HILTOS D. HORTON, Oak Ridge National Laboratory, Oak Ridge, Tenn.
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I n a n unbuffered solution, t h e titration of a neutral solution of fluorine with aluminum ions results in a n abrupt change of p H a t the stoichiometric end point. Details of t h e separation of fluoride from interfering substances were presented: only phosphate and highly associated fluoride complexes such as PbF2, CaF2, and AlFs--- require distillation. The procedure, a s given, employing a recording pH meter, will determine fluoride in a solution of sodium fluoride with a standard deviation of less t h a n 0.2% and in a s d u t i o n of SiF6-with a standard deviation of 0.6%. T h e method is applicable in t h e range of 0.1 t o 3.5 mg. of fluoride per ml. This procedure is a greatly improved modification of t h e method of Kurtenacker and Jurenka. Chronopotentiometry. Application to Organic Compounds. C H ~ R L EK. S REILLEY,University of North Carolina, Chapel Hill, N. C. Two transient types of polarography have recently been studied by various investigators. Each type employs unstirred solutions and electrodes of fixed area. hlathematiczl treatment exists for these cases based upon linear diffusion where either a sudden constantcurrent or a scanning-voltage causes t h e transient response. T h e features pertinent to the sudden application of constant-current, "chronopotentiometry," were reviewed and t h e application t o various organic compounds was discussed. Several compounds which yield only single waves by t h e usual d.m.e. polarography give multiple waves by the chronopotentiometric method. Determination of Water in Fluoride Salts. W.J. ROSS ASD J. C'. WHITE,Oak Ridge National Laboratory, Oak Ridge, Tenn. The removal of water by extraction with xylene and its subsequent determination by titration with Karl Fischer reagent have been successfully adapted to tlie determination of traces of mater in solids. Spectrotitrimetric Determination of Esters in Mixtures of Benzyl Benzoate and Dibutyl Phthalate. PAULL. DAVISA N D C. V. BOWEN, Agricultural Research Service, Entomology Research Branch, Orlando, Fla. I n a study of cloth impregnation with a mixture of benzyl benzoate and dihutyl phthalate it was necessary t o determine t h e components of this mixture in cloth patches. A method was devised in which the quantity of alkali used in a saponification and t h e absorbance reading a t 230 mp were used t o determine the quantity of each of these esters. T h e procedure in which titration and spectrophotometric readings are used to analyze for mixtures of the same type of compound is new and has many applications. Analysis of Normal Human Tissue by Emission Spectrography. ISABEL H. TIPTOS,ROBERTL. STEIXER,WILLIAMD . F O L . ~ N D , JOH.kNN.4 MUELLER, ASD & ~ R STANLEY, Y T h e University of Tennesaee and Oak Ridge Kational Laboratory, Oak Ridge, Tenn.
Dry-ashed samples of 18 different tissues from 25 autopsies of instantaneous death have been analyzed for 19 elements--kg, 41, Au, Bi, C d , Co, C r , Cu. Ga, Ge. M n , hlo, Ni, P b , Sb, Sn, Ti, T1, Zn-by emission spectrography. Zinc, copper, aluminum, and lead were found in every sample examined. Cadmium was found in every kidney and titanium in every lung. Chromium, nickel, silver, and tin occurred in more t h a n half the samples, and cobalt, gallium, molybdenum. and gold less frequently. dntimony occurred in one sample and germanium and thallium not a t all within the limits of sensitivity of t h e method. Measurement of Oxidation-Reduction Potentials of Biological AND TRL-EW. ROBINSON, University of Couples. OWENK. TIDWELL dlabama, Medical Center, Department of Physiology, Birmingham, Ala. Applications of oxidation-reduction potential measurements to biological systems are manifold, one of the most important being t h e determination of the free energy of reversible reactions. Most biological couples are extremely sensitive to oxygen. This netlessitates t h e use of a n anaerobic closed system for determination of the 0 - R potential. .In apparatus was designed and constructed which is simpler to use t h a n previous models. is more versatile, and is capable of producing highly accurate 0 - R potentials. This new system and its applic.ation to biological studies were discussed.
of these chemicals are highly sensitive to oxygen. An apparatus and technique were devised which allow spertrophotometric measurements to be made both in t h e visible and ultraviolet and also under aerobic and anaerobic conditions. This new technique and data obtained by ita uie were presented. Colorimetric Determination of Heteroauxin. P X C LD. ~ ~ O Z L E TRCEIT. ROBINSON, University of .\lahama, Medical Center, Birmingham, .\la.
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This method utilizes a reagent (p-dimethylaminobenzaldehyde) which will produce color with certain molecules containing a n indolelike structure. Utilizing this method, blood concentrations as low as 0.1 mg. per ml. of heteroauxin (+%indoleacetic acid) can be determined after a chloroform extraction process. Transmittance is determined on the Coleman Universal spectrophotometer a t 550 mp with Filter 214. Role of the Supervisor in a n Analytical Chemistry Laboratory. C. D . SUS.ANO. Oak Ridge National Lahoratory, Oak Ridge. Tenn. The role of the supervisor in a n analytical chemistry laboratory was considered from the standpoint of his responsibilities in operating the laboratory t o fulfill its prime objectire of accuracy, precision. anti speed in the performance of its work function. T h e operation;. of analytical chemistry involve a high degree of technique and the development of the highest skill require6 constant practice in the apylication of these techniques. The work of the analyst was compared with t h a t of artisans, artists, and others engaged in such profe*sionq in which a high degree of manual skill cwipled with some knowledge of the processes ia required. Flame Photometric Study of Boron. JOHSA. D E A NA N D C L\ R I C E THOMPSON, University of Tennessee, Knoxville, Tenn. The study was undertaken to develop a flame photometric method for boron, and in particular to adapt it to t h e Beckman D U spertrophotometer. T h e effect of acid concentration, methanol concentration, and vsrious anions and cations c,ommonly associated with boron upon the flame emission of boron in 1 to 1 methanol-mater solution were studied. T h e flame photometric method is more rapid than existing chemical methods, and is comparahle in accuracy and prerii;ion to existing chemical and spectrographic procedures. Factors Involved in the Application of Flame Photometry to the Determination of Alkalies in Mixtures. H . P. H O W E A N D JEANNE M. ROGERS,Oak Ridge National Laboratory, Oak Ridge, Tenn. Sodium, potassium, rubidium, and cesium can he determined in mixtures by means of t h e Beckman flame photometer. Limits of detection and of error have been established. Evaluations have been made of interferences encountered with vertain combinations of tilehe metals and correction tables have been assembled. Flame Spectrophotometric Determination of Lithium in Lithium ASD JAMES L. K.\HSSER,Eniversity cjf Minerals. VIRGIL.M.BENZON Alabama, Tuscaloosa, Ala.
-1rapid determination for lithium has heen developed with the iiie of the flame specatrophotometer. The procedure does not require tlie removal of interfering elements or the prior analysis of t h e sample-. The effect of enhancement or inhibition of the lithium excitation caused by other elements was eliminated by controlling the pH of the final solution with a citric acid-ammonium citrate buffer. Sample. containing 7.52 to 0.22% lithium oxide were analyzed with a n average error of less t h a n 27, of the amount present. Flame Photometric Determination of Copper in Nonferrous Alloys. JOHN A. DEAS, University of Tennessee, Knoxrille. Tenn. This investigation was undertaken to develop a flame photometric. method for copper in various commercial alloys.. The emission charac,terirtics of the two resonance lines of copper, Cu 323.7 m p and ('11 337.4 mp, were studied in acetylene-oxygen flame for various fueloxygen ratios. In addition, the .Ig 328.0 mp resonance line was studied with the intention of employing silver as a n internal standard element. Of the elements investigated, only appreriable amounts of nickel, rohalt, magnesium, calcium, and iron offer interference. T h e noninterference of large quantities of aluminum, zinc, and lead is noteworthy, and enables the flame photometric method for copper t o he applied to alloys of these base matrixe. without prior chemical separationa of the copper.
Spectrophotometric Analysis of Oxidation-Reduction Reactions of Titration of Acids in Dimethylformamide Using High Frequency. Biological Systems. T R U E W. ROBINSOX ASD OWENK . TIDWELL, JOHN d.DEAS A N D CARLCAIN,JR.,Unirersity of T e n n e s e e , KnoxUniversity of .\lahama, Medical Center, Birmingham, Ala. ville, Tenn. Since the historical work of Warburg, the spectrophotometric deThe purpose of t h e investigation was t o determine the applicability termination of oxidized and reduced forms of chemicals of biological of a high-frequency oscillator t o the titration of acids in dimethylinterest has become a n increasingly important field of research. Many
1856 formamide. Sharp V-shaped titration curves are obtained for strong acids and the ammonium ion over the complete range of the instrument's sensitivity, which includes concentrations as small as 0.0001M. Less acute angles are obtained in the titration of acids of intermediate strength. The high frequency method should be a useful adiunct for titrations in dimethylformamide. Chromatographic Methods. JOHN A. DE < N , University of Tennessee, Knoxville, Tenn. B general review of the basis for application of chromatographic techniques to the solution of specific problems was given. Application of Chromatographic Methods to Studies of Photosynthesis. G. R . NOGGLE, Southern Research Institute, Birmingham, Ala. Through the use of chromatographic methods, particularly paper chromatography, considerable progress has been made in working out the path of carbon in photosynthesis. Many of the biochemical stepi leading t o the formation of free sugars in plants are the reverse of reactions leading t o sugar glycolysis. Relation between Structure and Elution Position forthe SaccharideBorate Complexes. J. X. KHYM,L. P. ZILL, AND W. E. COHX,Oak Iiidge National Laboratory. Oak Ridge, Tenn. The well-known reaction between borate and polyhydroxy compounds t o give negatively charged borate complexes has been used t o develop an ion exchange method for the quantitative separation and analysis of components in various sugar mixtures. The sugars are ahsorbed on strong-base anion exchangers qvhich were previously converted t o the borate form. Elutions are carried out by successively increasing the concentration of borate ion, and effluent fractions are analyzed colorimetrically for sugar content. The sugars can be recovered in a pure form by removing the borate ion. This is accomplished by converting all borate t o boric acid and, in the presence of methanol, distilling off volatile methyl borate. Inspection of the elution curves obtained from the separation studies involving mono-, di-, tri-, and tetrasaccharides, sugar alcohols, glycosides, and the sugar phosphates revealed a pattern between elution positions and structures of the compounds. The relation between structure and elution position was discussed in detail.
ANALYTICAL CHEMISTRY between the phosphate group and the ring oxygen atom (as in glucose1- and ribose-1-phosphate) will lessen the degree of ionization; bonding between a hydrogen atom of an alcoholic group and an oxygen atom of a n adjacent phosphoryl group will increase the degree of ionization (as in ribose-3-phosphate). These considerations were discussed in the presentation of the elution curves for the pentose phosphates which are separated on the chloride or sulfate forms of a strong-base anion exchange resin. A similar case can be presented for the separation of the glycerol phosphates. Spectrophotometric and Solubility Investigations of Uranium(V1) Orthophosphate in Perchloric Acid Solutions. C. F. BAES,JR.,J. M . SCHREYER, AND J. M. LESSER,Oak Ridge National Laboratory, Oak Ridge, Tenn. Job's method of continuous variation has been applied t o COS(ClO4)rHaPOa mixtures in 1M and in 0.1.M perchloric acid. In both cases the data indicate the presence of complex species in which the ratio of PO4-3/UO2++ is unity.
Society for Analytical Chemistry T 22, for
HE Physical Methods Group met in Oxford, England, on October a meeting held jointly with the London Section of t h e Royal Institute of Chemistry. Presentation of papers was preceded by a visit to t h e A 4 t o ~Energy c Research Establishment a t Harwell.
Assay Equipment for a Radiochemical Laboratory. J. E. JOHSSIsotope School, Atomic Energy Research Establishment, Harwell.
TON,
The measurement of radioactive isotopes by ionization chambers, proportional counters, Geiger counters, and scintillation counters was briefly outlined. The features of each of these instruments of possible interest t o the analytical chemist were described, such as sensitivity, stability, and specialized applications as well as a list (including cost) of the electronic equipment required for each of the measuring methods. Three years' experience in the Isotope School with equipment supplied by the various manufacturers was described.
Purification and Analysis of 4-Aminopteroylglutamic Acid-2-C" (Aminopterin) by Chromatography and Bioautography. JAMESA. JOHNSON, JR., Southern Research Institute, Birmingham, A41a.
Determination of Gamma Isomer in Crude Benzene Hexachloride General by a Carbon-14 Isotope Dilution Method. D. E . PALIN, Chemicals Division, Research Department, Widnes.
4-Aminopteroylglutamic acid-2-Cl4 (aminopterin) having an activity of approximately 4.3 pc. per mg. was prepared from barium ~ a r b 0 n a t e - C by ' ~ known procedures. The final purification, especially aimed at removal of contaminating pteroylglutamic acid-Z-CI4 (folic acid), was effected by ion exchange chromatography using a Dowex 1 column. By a method combining one-dimensional paper chromatography and bioautography (using Streptococcus faecalis) the final product was shown t o contain less t h a n 0.25y0 but greater than 0.05% folic acid. Details of the techniques employed were presented.
An isotope dilution met,hod for the determination of gamma isomer in crude benzene hexachloride has been developed for use as a check on the other analytical procedures. A weighed amount, a , of radioactive pure gamma isomer of knoFn specific activity, 5 , is mixed with a suitable weight, b , of the crude benzene hexachloride and a sample of pure gamma isomer of diluted activity is separated by a combination of solvent extraction and partition chromatography. The specific activity, u , of this sample is determined by beta-particle counts, made in a methane flow proportional counter, on "thick" specimens of barium carbonate prepared by standard techniques of microcombustion, absorption, precipitation, and filtration. The percentage of gamma isomer, g, in the original crude sample is then given by the expression:
Paper Chromatographic Investigation of Maleic Hydrazide. J . EDGAR L. STEELE,Clemson Agricultural GRAYDINWIBDIE,JR.,. ~ N D College, Clemson, S. C. A chromatographic method for the isolation and identification of maleic hydrazide was developed. Along with the determination of suitable solvents and methods of locating the material on the paper, an investigation of some of the variables, such as initial location of the material on t h e paper and length of time required for the run, was carried out. Chromatographic Techniques in Studying the Mechanism of Metabolic Inhibitors in E . coli and Mouse Tissues. ARTHURJ. TOMISEK, Southern Research Institute, Birmingham, Ala. Two-dimensional paper chromatography of tissue extracts is a n excellent technique for exploratory experiments on inhibitor mechanisms. I n the case of azaserine, extensions of the chromatographic technique have been very useful in providing information on metabolic pathways and the mode of inhibition. The Hydrogen Bond a s a Factor in the Ion Exchange Separation of the Pentose Phosphates and the Glycerol Phosphates. J. X. K H Y M , A. B. OTTINGER, AND W. E. CORN,Oak Ridge National Laboratory, Oak Ridge, Tenn. Hydrogen bonding may act either t o increase or t o decrease the ionization of the phosphate group in the sugar phosphates. Bonding
o =
100a(z - u) bu
Physical and Analytical Control of the Radioactive Efauent from A.E.R.E., Harwell. R. H. BURNS, Industrial Chemical Group, Atomic Energy Research Establishment, Harwell. The paper gave details of the permissible levels of activity in the effluent from the Atomic Energy Research Establishnlent. These levels are based on the internationally accepted drinking water tolerances for radioactive isotopes. I n order to ensure t h a t the limits laid down are not exceeded, it is necessary t o estimate the radium, other alpha emitters, calcium and strontium, and the other beta-active isotopes in the liquid wastes. Details of the methods developed for this analytical control were given. The main source of activity in the effluent is derived from the isotopes formed during the fission of uranium. These fission products are numerous and very varied in chemical character. Brief details were given of the treatment processes used to decontaminate the effluent prior t o discharge t o the river Thames. Physical control of the waste material is accomplished by the design of special containers, a separate active drainage system, and treatment in a plant erected for this purpose. A description was given of the controls exercised at each stage of the disposal system from the laboratories to the Thames.
