AC BRIEFS

AC BRIEFS Highlights of the scientific a n d technical articles in this issue

Aliphatic Halo­

Theoretical Basis for a Continuous, Large-Ca­ pacity Gas Chromatographic Apparatus

The spectra of 103 monohalogenated aliphatic compounds are correlated. The correlation is useful for the identifi­ cation and structural elucidation of these type compounds. Molecular ion abundance is in the order I > Br > CI > F. Fragmentation of the molecular ion generally hecomes greater as the molecular weight and chain branching increase.

Λ theoretical analysis of a continuous gas chromatographic system is made with the object of delineating and com­ paring its potential capabilities with conventional systems. Problems peculiar to large scale-up arc investigated, and equations pertaining to the resolution of the de\*ice, used analytically or in preparative scale work, are derived.

Mass Spectrometric Analysis. genated Compounds

F. W . M c L A F F E R T Y , The Dow Chemical C o . , M i d l a n d , M i c h .

J. C. GIDDINGS,

University of Utah, Salt Lake C i t y

12, Utah

A n a l . C h e m . 34, 37 ( 1 9 6 2 )

A n a l . C h e m . 34, 2 ( 1 9 6 2 )

Mass Spectrometric Analysis. genated Compounds

Aromatic Halo-

The mass spectra of a series of monohalogenatcd aromatic compounds are correlated. The data obtained are appli­ cable for the identification and structural determination of these type compounds. The molecular ions are major peaks except for iodides, unsubstituted halobenzenes, and m-bromotohtene. The relative abundance of the molecu­ lar ions is in the order of iodide > bromide > chloride > fluoride.

Behavior of Inert Gas Packets in Chromato­ graphic Columns Experimental procedures are established whereby the effects of column geometry and dimension are separated from the effects of capacity ratio, liquid film thickness, and unwanted chemical attraction. Comparison is obtained between a diatomaceous earth support column and a glass bead support of approximately the same mesh size. S. D. N O R E M , The Perkin-Elmer C o r p . , Norwallt, C o n n . A n a l . C h e m . 34, 4 0 ( 1 9 6 2 )

F. W . M c L A F F E R T Y , The Dow Chemical C o . , M i d l a n d , M i c h . A n a l . C h e m . 34, 16 ( 1 9 6 2 )

Mass Spectrometric Analysis. Aliphatic Nitriles

Factors Affecting the Chromatographic Analysis of Asphaltic Petroleum and of Recent Marine Sediment Organic M a t t e r

Mass spectrometry is used for the identification and struc­ ture determination of certain aliphatic nitriles. The spectra of these nitriles are correlated. Molecular ion abundance is low above C a , but still appreciable at G». The data may be employed for the identification of molecular weight.

An evaluation is made of the effects of high molecular weight material on the chromatographic separation effici­ encies of rock and sediment organic matter. The presence of these materials in the alumina column retard some of the points of eluate effluence. Separation efficiencies are dependent on the volume of eluents employed.

F. W . M c L A F F E R T Y , The Dow Chemical C o . , Framingham, Mass. A n a l . C h e m . 34, 26 ( 1 9 6 2 )

Gasoline Type Analysis by Mass Spectrometer Using Computer Assembled Matrices Hydrocarbon types in nonolefinic gasolines are determined by mass spectrometric analysis using an electronic com­ puter to calculate matrices. The procedure differs from other methods in that the molecular weight distribution of each major compound type in the sample is used in selection of a matrix for calculation of results. P. J . K L A A S and W . P. M c S W E E N E Y , Esso Research and Engi­ neering C o . , Linden, N . J . A n a l . Chem. 34, 30 (1962)

Correlation of Mass Spectra with Structure in Aromatic Oxygenated Compounds. Benzoate Type Esters Structural features are ascertained for certain methyl benzoates and benzyl benzoates by correlation of their mass spectra. The nature of the oxygenated functional groups and the position of the methyl group substituted on the ring are the major spectral characteristics. The data may serve for the identification and determination of this type of compound. T H O M A S A C Z E L and H . E. L U M P K I N , H u m b l e O i l and Refining C o . , Baytown, Tex. A n a l . C h e m . 34, 33 ( 1 9 6 2 )

PAULETTE H A M W A Y , M I C H A E L C E F O L A , and B A R T H O L O ­ M E W Ν Α Θ Υ , Fordham University, N e w York 58, Ν . Υ . A n a l . C h e m . 34, 43 ( 1 9 6 2 )

Isoprenoid Hydrocarbons in Petroleum. Isola­ tion of 2,6,10,14-Tetramethylpentadecane by High Temperature Gas-Liquid Chromatography High temperature gas chromatography is used for the iso­ lation of 2,6,10,14-tetramethylpentadecane from petroleum samples. This hydrocarbon is identified by mass, in­ frared, and proton magnetic resonance spectroscopy. Its occurrence supports theories of the origin of petroleum from natural sources, such as chlorophyll. J . G . B E N D O R A I T I S , B. L. B R O W N , and L. S. H E P N E R , Socony M o b i l O i l C o . , Inc., Paulsboro, N . J . A n a l . C h e m . 34, 49 ( 1 9 6 2 )

Automatic Recording Device for Monitoring the Effluent from Chromatographic Columns An automatic recording monitor is constructed for use with the chromatographic separation of protein fractions of animal serum. The instrument uses monochromatic light in the visible and ultraviolet regions with photomultiplier detectors and a logarithmic response cathode. P. V. A V I Z O N I S and J . C . W R I S T O N , ware, Newark, D e l .

Jr., University of

Dela­

A n a l . C h e m . 34, 54 ( 1 9 6 2 )

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Device for Measuring the Resistance of Solutions Linearly and Continuously A servomechanical monitor is constructed for continuous and linear measurements of resistance in solutions. A servoamplifier is used to detect voltage imbalance caused by changes in resistance. T h e device is applied t o t h e study of salt gradients in ion exchange fractionation of protein solutions. P. V. AVIZONIS, FRED FRITZ, and J . C. WRISTON, Jr., University of Delaware, Newark, Del. Anal. Chem. 34, 58 (1962)

Gas Chromatographic Determination of Oxida­ tion Products of Isobutylene. Hydroxy Acids, N i t r a f o Acids, and Related Compounds Acids resulting from the oxidation of isobutylene with dinitrogen tetroxide and nitric acid are quantitatively determined by gas chromatography. T h e acids are esterified using diazomethane and applied to the column. Hydrogen is used as the carrier gas. An analysis is con­ ducted within 20 minutes. LOUIS MIKKELSEN and R. S. RICHMOND, Escambia Chemical Corp., Wilton, Conn. Anal. Chem. 34, 74 (1962)

Quantitative Gas-Solid Chromatographic Deter­ mination of Carbonyl Sulfide as a Trace Impurity in Carbon Dioxide A gas-solid chromatographic method is developed for de­ termining trace amounts of carbonyl sulfide as an impurity in carbon dioxide. Reliable results are obtained over a concentration range of 0.5 to 2700 p.p.m. Resolution is accomplished using a silica gel column and argon as the inert gas. H. L. HALL, The Coca-Cola Co., Atlanta I, Ga. Anal. Chem. 34, 61 (1962)

Solvent Extraction and Anion Exchange Chroma­ tography for the Spectrophotometry Deter­ mination of Calcium Pantothenate in Pharma­ ceutical Products Calcium pantothenate in multivitamin products is deter­ mined by a modified solvent extraction procedure. Cal­ cium pantothenate is chromatographed and hydrolyzed and reacted with l,2-naphthoquinone-4-sulfonate. T h e maximum absorbance is measured at 465 π\μ. Biological extracts and free amino acids do not interfere. THAVIL PANALAKS and J . A. CAMPBELL, Department of Na­ tional Health and Welfare, Ottawa, Canada Anal. Chem. 34, 64 (1962)

Use of Gas Chromatography for Rapid Deter­ mination of Carbonate a t Low Levels A rapid and sensitive gas chromatographic method is used for the determination of small amounts of carbonate. T h e carbon dioxide is evolved with acid and a fraction ex­ panded into a gas buret which is then measured by gas chromatography. F. G. CARPENTER, National Bureau of Standards, Washington, D. C. Anal. Chem. 34, 66 (1962)

Analysis of Chlorophenols by Gas-Liquid Chro­ matography Mixtures of chlorophenols are quantitatively analyzed by gas-liquid chromatography. T h e method is inexpensive and found to be as effective as the infrared spectrometric procedure. Several mixtures are analyzed by both proce­ dures and the results compared.

Separation of the Alkali Metal Cations from Mixtures of Various Cations by Electrochromatography Alkali metal ions are separated from univalent silver, thallium, and mercurous ions and from various multivalent ions by electrochromatographic technique. Quantitative determinations are made by flame photometry or activa­ tion analysis. JOSEPH SHERMA and Η. Η. STRAIN, Argonne National Lab­ oratory, Argonne, III. Anal. Chem. 34, 76 (1962)

Paper Chromatography Compounds

A gas-liquid chromatographic procedure is devised for de­ termining small amounts of hydrocyanic acid in water. The method is based upon solution-air distribution of hydrogen cyanide and analysis of the vapor. Sensitivity and specificity are obtained by using a concentration step and amplification of the thermistor detector output. C. R. SCHNEIDER and HARRY FREUND, Oregon State University, Corvallis, Ore. Anal. Chem. 34, 69 (1962)

Organic

Mercury

A paper chromatographic procedure is devised for the separation and determination of organic mercury com­ pounds. The sample is dissolved in dioxane and chromatographed on paper using a 1-butanol-ethanol-ammonia system. T h e compounds are spotted with a chloroform solution of dithizone or aqueous sodium stannite. J. N. BARTLETT and G. W . CURTIS, St. Joseph's College, Philadelphia 31, Pa. Anal. Chem. 34, 80 (1962)

Determination of Normal Paraffins i n C20 to C 3 2 Paraffin Waxes by Molecular Sieve Adsorption. Molecular Weight Distribution by Gas-Liquid Chromatography Normal paraffins in paraffin waxes are determined by Molecular Sieves technique. The sample is refluxed in iso-octane containing pelleted Molecular Sieves. After filtration the filtrate is evaporated leaving branched and cyclic paraffins as the residue. T h e weight difference be­ tween the residue and the original sample indicates the amount of normal paraffins. J. G. O'CONNOR, F. H. BUROW, and M. S. NORRIS, Gulf Research and Development Co., Pittsburgh, Pa.

J . A . BARRY, R. C. VASISHTH, and F. J . SHELTON, Reichhold Chemicals, Inc., Seattle 24, Wash. Anal. Chem. 34, 67 (1962)

Determination of Low Level Hydrocyanic Acid in Solution Using Gas-Liquid Chromatography

of

Anal. Chem. 34, 82 (1962)

Spectrographs Uranium Ore

Determination

of

Thorium

in

An emission spectrographic method is used for determin­ ing the thorium content of uranium ores. Thorium is separated and purified by lanthanum fluoride precipitation and extracted with thenoyltrifluoroacetone. The method will determine as little as 0.1 p.p.m. thorium. ROY KO and M. R. WEILER, General Electric Co., Richland, Wash. Anal. Chem. 34, 85 (1962) VOL. 34, NO. 1, JANUARY 1962

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for

Titration of Uranium with Potassium Dichromate. Determination of Disproportionality Effects

The trace impurities, arsenic and bismuth, in germanium powder and germanium dioxide are determined by emission spectrographic technique. T h e sample is concentrated and the impurities extracted with a solution of the diethyl ammonium salt of diethyl dithiocarbamic acid in chloroform. T h e procedure is checked against chemical determination on standard and unknown samples.

The error of disproportionality encountered in the visual end-point determination in the titration of uranium with potassium dichromate is overcome by using a potentiometric technique. T h e error is attributed to the indicator, diphenylaminesulfonic acid. A potentiometric method determines as little as 10 milligrams of uranium.

Spectrographic Analysis of Traces of Arsenic and Bismuth

Germanium

T. J . VELEKER, Sylvânia Electric Products, Inc., Towanda, Pa.

J. Ε. Α. ΤΟΝΙ, Argentina

Atomic

Energy

Commission,

Buenos

Aires,

Anal. Chem. 34, 99 (1962)

Anal. Chem. 34, 87 (1962)

Cation Exchange Separation of Metal Ions with Hydrobromic Acid Radiochemical Determination of Ruthenium by Solvent Extraction and Preparation of CarrierFree Ruthenium Activity An extraction procedure is outlined for the separation and determination of ruthenium in neutron-irradiated plutonium. Ruthenium tetroxide is selectively extracted with carbon tetrachloride from aqueous solution. Ruthenium is then extracted into sodium hydroxide and precipitates as mixed oxides which are counted by beta or gamma measurement.

M e r c u r y ( I I ) , b i s m u t h ( I I I ) , cadmium(IV), tin(IV), and lead(II) are separated from other metals by a cation exchange technique. These metals are eluted from the column with dilute hydrobromic acid. By varying the concentration of the acid, the metals may be separated from each other. J. S. FRITZ and Β. Β. GARRALDA, Iowa State University, Ames, Iowa Anal. Chem. 34, 102 (1962)

J . W . T. MEADOWS and G. M. MATLACK, University of California, Los Alamos Scientific Laboratory, Los Alamos, N. M.

Polarimetric Determination of Boric Acid with Tartaric Acid

Anal. Chem. 34, 89 (1962)

Small quantities of boron are determined by polarimetric technique using tartaric acid solution and boric acid. T h e method is superior to the one using mannitol as reagent. Silica does not interfere.

Determination of Small Amounts of Cobalt by Isotope Dilution Analysis Small amounts of cobalt in copper alloys and ingot irons are accurately determined by isotopic dilution analysis. This technique is combined with solvent extraction and spectrophotometry to give a reliable procedure. Co60 is used as the radioactive tracer. W . D. RALPH, Jr., T. R. SWEET, and INARA MENCIS, The Ohio State University, Columbus 10, Ohio Anal. Chem. 34, 92 (1962)

KAZUNOBU KODAMA and HAZIME SHIIO, Nagoya Municipal Industrial Research Institute, Atsuta-Ku, Nagoya, Japan Anal. Chem. 34, 106 (1962)

New Fire Assay for Iridium A fiie assay for determining iridium involves the collection of iridium on a copper-nickel-iron button. The button is dissolved in acid and iridium separated by cation ex­ change technique. Depending upon the quantity, iridium is measured either gravimetrically or spectrophotometrically. G. G. TERTIPIS and F. E. BEAMISH, University of Toronto, Toronto, Canada Anal. Chem. 34, 108 (1962)

Spectrophotometric Determination of Ruthenium with 2-Nitroso-l-Naphthol Microquantities of ruthenium are determined by spectrophotometric analysis using 2-nitroso-l-naphthol as reagent. T h e sample solution is acidified with hydrochloric acid and saturated with sulfur dioxide. Ruthenium reacts with the reagent to give a colored complex having a maximum absorbance at 600 ιημ. Uranium does not interfere. D. L. M A N N I N G and OSCAR Laboratory, Oak Ridge, Tenn.

MENIS, Oak Ridge

National

Volumetric Determination of Uranium in the Presence of Niobium Utilizing a Bismuth Metal Reductor Uranium is determined in the presence of niobium by a volumetric procedure using a bismuth metal column. On the column, uranium(VI) is reduced to uranium(IV) with no uranium(III) or niobium(III) being formed. Uranium is measured by indirect volumetric titration. Some metallic interference is encountered.

Anal. Chem. 34, 94 (1962)

R. J . JAWOROWSKI and W . D. BRATTON, Pratt & Whitney Aircraft, CANEL, Middletown, Conn. Anal. Chem. 34, I I I (1962)

Determination of Sodium in Silicate Minerals and Rocks by Neutron Activation Analysis

Identification of Precipitates in Diffusion Zones Using the Electron Probe Microanalyzer

The determination of sodium in a wide range of silicate rocks is accomplished by pile neutron activation analysis. The sample is irradiated and the gamma-rays of sodium-24 are counted in an integral scintillation counter. T h e procedure does not require any chemical processing.

In solid-solid diffusion studies, small precipitates form in the diffusion zone. These are due to a reaction between impurities in one parent metal and incoming atoms of the other parent metal. T h e precipitates are identified and analyzed by using an electron probe microanalyzer. T h e impurity responsible for the reaction is also determined.

G . L. SCHROEDER and J . W . WINCHESTER, Massachusetts In­ stitute of Technology, Cambridge 39, Mass. Anal. Chem. 34, 96 (1962)

R. E. SEEBOLD and L. S. BIRKS, U. S. Naval Research Laboratory, Washington 25, D. C. Anal. Chem. 34, 112 (1962) VOL. 34, NO. 1, JANUARY 1962

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X-Ray Absorption Edge Analysis Elements, such as zirconium, niobium, molybdenum, thorium, and uranium are accurately determined by x-ray absorption edge analysis. T h e procedure is relatively free from interference. Several elements may be determined in the same solution, and the solution is not consumed or contaminated. All elements except those with low atomic numbers may be determined. H . W . D U N N , O a k Ridge N a t i o n a l Laboratory, O a k Ridge, Tenn. A n a l . C h e m . 34, 116 ( 1 9 6 2 )

X-Ray Method for Determining Liquid Densities a t High Temperatures and Pressures An x-ray photographic technique is developed for deter­ mining liquid densities at high temperatures and pressures. The position of the vapor-liquid interface is located by x-ray, and these data, in reference to the weight of the solution, are used to calculate the density. N . A . K R O H N and R. G . W Y M E R , O a k Ridge N a t i o n a l Labora­ tory, O a k Ridge, Tenn. A n a l . C h e m . 34, 121 ( 1 9 6 2 )

Rapid, Automatic X-Ray Analysis of Magnesium Alloys The major alloying constituents of magnesium alloys are determined by an accurate and direct x-ray fluorescence procedure. Complete analyses for zirconium, zinc, tho­ rium, cerium, neodymium, praseodymium, and lanthanum are obtained within one hour with results comparable to wet chemical and spectrographic methods. G . A . S T O N E R , The Dow Chemical C o . , M i d l a n d , M i c h . A n a l . C h e m . 34, 123 ( 1 9 6 2 )

Precise Phase Transition Measurements of Or­ ganic Materials by Differential Thermal Analysis An improved differential thermal analysis technique is used for determining phase transition temperatures. T h e procedure is based on the use of small undiluted samples and continuous temperature measurements within the sample. A precision of ±0.3° C. is indicated. D. A . V A S S A L L O and J . C . H A R D E N , E. I. du Pont de Nemours & C o . , Inc., W i l m i n g t o n , D e l . A n a l . C h e m . 34, 132 ( 1 9 6 2 )

Calculation of Thermogravimetric Data by Elec­ tronic Digital Computer A program is reported for computation of temperature, weight, weight loss, and rate of reaction from electromo­ tive force data. T h e data are used to indicate these values during thermogravimetric decomposition. T h e technique employs an electronic digital computer. J . R. S O U L E N , Pennsalt Chemicals C o r p . , W y n d m o o r , Pa. A n a l . C h e m . 34, 136 ( 1 9 6 2 )

Completely Automatic, Coulometric Titration Apparatus for Process Use. Determination of Sulfur Dioxide in Gases with Concentrations Ranging from 0.1 to 1 0 0 % by Volume An automatic recording coulometric titration procedure determines sulfur dioxide in gaseous materials. The sulfur dioxide is absorbed in sodium hydroxide and the solution transferred to an acidic bromide solution. T h e sulfur di­ oxide is titrated with electrically-generated bromine. T h e method determines from 0.1 to 100% by volume sulfur dioxide. EMBRECHT BARENDRECHT and W I L H E L M U S Staatsmijnen in Limburg, G e l e e n , Netherlands

MARTENS,

A n a l . C h e m . 34, 138 ( 1 9 6 2 )

Solubilization of Sulfonic Acids for Infrared Studies. Some Analytical Applications A simple method is described for solubilizing many sul­ fonic acids and certain other acidic compounds in carbon disulfide. T h e liquid anion exchange resin, Amberlite LA-2, is used as the solubilizing agent. T h e acid-resin salts are dissolved in carbon disulfide by several tech­ niques depending upon the acid involved. M E Y E R D O L I N S K Y and C H A R L E S S T E I N , Department of H e a l t h , Education, and W e l f a r e , Washington 25, D. C . A n a l . C h e m . 34, 127 ( 1 9 6 2 )

Infrared Determination of Vinylidene Unsaturation in Polyethylene A method is presented for the correction of butyl inter­ ference at the vinylidene frequency in infrared analysis. The method is based on the fact that the absorbance ratio of the 1378-cm."1 methyl band t o the 895-cm."1 butyl band is constant. Therefore, the number of butyl groups is proportional to the number of methyl groups, and the extent of butyl interference is calculated. J . N . L O M O N T E , The Dow Chemical C o . , Freeport, Tex. A n a l . C h e m . 34, 129 ( 1 9 6 2 )

A Potentiostat for Amperometric Kinetic Studies A potentiostat technique is incorporated into ampero­ metric titration studies involving redox couples. T o bal­ ance the decrease in the potential of the solution as ions are reduced, similar ions are anodically regenerated. T h e current consumed in the electrolysis is proportional to the reduction rate. J . M . M A T S E N and H . B. L I N F O R D , Columbia University, N e w York 27, Ν . Υ . A n a l . C h e m . 34, 142 ( 1 9 6 2 )

Polarographic Characteristics of Carbohy­ drates. The Aldose Oximes and Semicarbazones Aldose oximes and semicarbazones are determined by polarographic technique. Polarograms are obtained for these compounds over a range of p H 1 to 6 using a drop­ ping mercury electrode. A linear relationship exists be­ tween the current and the concentration of the sample. J . W . H A A S , Jr., and J . D. STOREY, G r o v e C i t y C o l l e g e , G r o v e C i t y , Pa., and C . C . L Y N C H , University of Delaware, Newark, D e l . A n a l . C h e m . 34, 145 ( 1 9 6 2 )

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BRIEFS Potentiometric Titration of Very Weak Acids. Effect of Potassium on the Glass Electrode In the potentiometric titration of very weak acids with a strong base, the inverted inflections are caused by potassium ions in the titrant. T h e peculiar shape of the titration curve is a result of two simultaneous titrations, the one intended and the titration of the active surface of the electrode with potassium ions. G . A . H A R L O W , Shell Development C o . , Emeryville, C a l i f . A n a l . C h e m . 3 4 , 148 ( 1 9 6 2 )

Identification of Nitrogen Compounds by C a t a lytic Denitrogenation A catalytic hydrogénation technique is used in the identification of nitrogen compounds. T h e hydrogen replaces the nitrogen in the parent compound, resulting in paraffin or cycloparaffin structures which are more easily identified. The technique is applied to pure compounds and mixtures of nitrogen compounds. C . J . T H O M P S O N , H . J . C O L E M A N , C . C . W A R D , and H . T. RALL, U . S. Department of the Interior, Bartlesville, O k l a . A n a l . C h e m . 34, 151 ( 1 9 6 2 )

Identification of Halogen Compounds by C a t a lytic Dehalogenation A microhydrogenation technique is used for characterizing halogen compounds. Catalytic hydrogénation quantitatively removes halogen atoms from the compound giving the parent paraffin or cycloparaffin, which is more easily identified. T h e method responds to sample volume size as small as 0.0002 milliliters.

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C . J . T H O M P S O N , H . J . C O L E M A N , C . C . W A R D , and H . T. RALL, U. S. D e p a r t m e n t of the Interior, Bartlesville, O k l a . A n a l . C h e m . 34, 154 ( 1 9 6 2 )

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Resorcinol in mixtures with phenol, hydroquinone, and catechol is quantitatively determined by colorimetric analysis. T h e sample solution is buffered and iodine added. T h e resulting colored complex is extracted with butyl acetate. Maximum absorbance of the extract is measured at 750 ναμ. M A U R I C E C O D E L L and L E O N A R D TEITELL, Frankford Arsenal, Philadelphia 3 7 , Pa., and E D G A R H O W A R D , Jr., Temple Uni­ versity, Philadelphia, Pa. A n a l . C h e m . 34, 157 ( 1 9 6 2 )

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Procedural details are given for the preparation of azides from crude, unpurified diazotype extracts and their isola­ tion at sufficient purity for identification by spectrophotometric analysis. T h e method is applied to analysis of sensitized diazotype paper extracts. W . L. E V A N S , R. G . D. M O O R E , and J . E. R E D D I N G , Aniline and Film C o r p . , Johnson C i t y , Ν . Υ .

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A n a l . C h e m . 3 4 , 159 ( 1 9 6 2 )

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Identification of Sensitizers in Diazotype Prod­ ucts by Conversion to Azides

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Determination of Resorcinol in Solutions Containing Phenol, Hydroquinone, and Catechol

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