AC
BRIEFS Highlights of the scientific and technical articles in this issue
Application of Total Ionization Principles to Mass Spectrometry Analysis
Chromatography of a Mixture of Hexane, Chloroform, and Benzene on Silica Gel
An analytical expression relating total ionization per mole to molecular weight has been derived from relative ionization cross-section study of Otvos and Stevenson. T h i s equation predicts that total ionization data for h o m o l o g o u s hydrocarbon series are linear functions of molecular weight having same slope.
Increase of free water content in silica gel decreases its resolving p o w e r in chromatographic fractionation of a hexane, chloroform, benzene mixture because it de creases adsorption. T h r e e compositions were sepa rated from the mixture by the moist silica gel. J. W . BLAIR and E. S. AMIS, University of Arkansas, Fayetteville, Ark.
G . F. CRABLE and N . D. COGGESHALL, Development Co., Pittsburgh, Pa.
Gulf
Research
and Anal. Chem. 3 0 , 3 2 9 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 1 0 ( 1 9 5 8 )
Direct Determination of Isoparaffins and η-Paraffins in Olefin-Free Gasoline by Mass Spectrometer Resolution of normal and isoparaffins in any 100° to 4 0 0 ° F. h y d r o c a r b o n mixture containing less than 3.0% olefin, using data from a single mass spectrometer run, is carried out as an extension of any hydrocarbon-type analysis which expresses results in liquid volume p e r cent. Accuracy is estimated to be within 1 0 % in most cases.
Resolution of Isomeric Hexanes by Gas-Liquid Chromatography Hexane isomers can be rapidly resolved by gas-liquid chromatography using new column packings consisting of heterocyclic amines o n Celite. Resolution of 2,3dimethylbutane and 2-methylpentane is achieved in 15 minutes, while all hexane isomers can be separated in less than 30 minutes. ALBERT ZLATKIS, University of Houston, Houston, Tex. Anal. Chem. 3 0 , 3 3 2 ( 1 9 5 8 )
W . C. FERGUSON and H. E. H O W A R D , Union Oil Co. of California, Brea, Calif. Anal. Chem. 3 0 , 3 1 4 ( 1 9 5 8 )
Mass Spectrometer-Type Analysis for Olefins in Gasoline Benzenesulfenyl chloride reacts quantitatively with olefins in a h y d r o c a r b o n mixture to form a high boiling addition product which does not contribute t o mass spectrum of the nonolefinic components. By comparison of mass spectra before and after treatment with this reagent, the olefin, monocycloparaffin, coda, and dicycloparaffin mass peaks may be determined separately. LOUIS MIKKELSEN, R. L. HOPKINS, and D. Y. YEE, U. S. Bureau of Mines, Bartlesville, O k l a .
Alternating Current Polarography. Improved Experimental Arrangement, Examination of Theory, and Study of Cadmium(ll) Reduction T e c h n i q u e of alternating current polarography employs an alternating potential of millivolt amplitude super posed o n a steady polarizing potential. Fundamental theoretical and experimental factors are critically re viewed. N e w handling of experimental and calculated data facilitate use of technique. Series circuit resistances are minimized and corrected for. H. H. BAUER and P. J. ELVING, University of Michigan, Ann Arbor, Mich. Anal. Chem. 3 0 , 3 3 4 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 1 7 ( 1 9 5 8 )
Low Voltage Techniques in High Molecular Weight Mass Spectrometry Mass spectra of double-bond-containing molecules can be greatly simplified by lowering ionizing voltage so that energy available is sufficient to form molecule ion, but too l o w to form fragment ions. Use of this technique in higher boiling ranges of petroleum simplifies interpreta tion of spectra. Calibration data and examples are given. H. E. LUMPKIN, Humble Oil and Refining Co., Baytown, Tex. Anal. Chem. 3 0 , 3 2 1 ( 1 9 5 8 )
Some Factors Influencing the Efficiency of Gas-Liquid Partition Chromatography Columns A study has been made of effect of following parameters o n efficiency of a gas-liquid partition chromatographic column: nature and velocity of carrier gas, column temperature, particle size of solid support, density of packing and amount of liquid phase used. Results agree well with rate theory of van Deemter, Zuiderweg, and Klinkenberg.
Alternating Current Polarography. Determination of Transfer Coefficient of Electrochemical Processes Apparatus and technique described for use in sinusoidal wave alternating current polarography have been modi fied to determine transfer coefficients of electrochemical reactions with a precision of about ± 0 . 0 1 . Simple and rapid procedure, a modification of that p r o p o s e d by van C a k e n b e r g h e using a suitable frequency filter, is based o n measurements of even harmonics of the alternating cur rent. H. H. BAUER and P. J. ELVING University of Michigan, Ann Arbor, Mich. Anal. Chem. 3 0 , 3 4 1 ( 1 9 5 8 )
Voltammetry at Solid Electrodes. Polarography of Sulfa Drugs
Anodic
Anodic oxidation of sulfa drugs is investigated at a rotat ing platinum electrode by a current-scanning technique. Sulfa d r u g s show anodic waves with Ei/i's from + 0 . 7 5 to 1.05 volts vs. S.C.E. in p H r a n g e 1 to 9. Sulfapyridine, sulfisomidine, and sulfadiazine can be quantitatively determined in r a n g e of about 4 X 10~ 5 to 1 Χ 10~4Λ1 with a reproducibility to ="= 1 to 3 %.
W . J. de WET and VICTOR PRETORIUS, University of Pretoria, Pretoria, South Africa
J. D. VOORHIES and R. N . ADAMS, Princeton University, Princeton, N . J.
Anal. Chem. 3 0 , 3 2 5 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 4 6 ( 1 9 5 8 )
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BRIEFS Square-Wave Polarograph
A square-wave polarograph has been designed and con structed with a circuit such that fundamentals of the method could be studied. Performance is reported as a function of variable elements in the circuit. It is less sensitive than Barker square-wave polarograph, but its resolution is about the same and it is much simpler elec tronically. R. Ε. Η Α Μ Μ , University of Utah, Salt Lake City, Utah
Quinoxaline-2,3-dithiol as a Colorimetric Reagent. Determination of Nickel in A m m o n i a c a l Solutions
The nickel complex of quinoxaline-2,3-dithiol imparts an intense reddish color to ammoniacal solutions. Con centrations in range of 0.3 to 3.0 p.p.m. can be deter mined with a relative accuracy of 1%. Silver, copper, cobalt, and manganese interfere. D. A. S K O O G , M I N G - G O N University, Stanford, Calif.
LAI,
and
Anal. Chem. 3 0 , 3 5 0 ( 1 9 5 8 )
Automatic Determination of Uranium in Process Streams
An automatic instrument composed of a derivative polarograph and a rotary-valve proportioning system analyzes high concentrations (100 to 200 grams per liter) of uranium in process streams. Resistance-capaci tance method of derivative polarography using a reversescanning procedure gives highly reproducible results. Uranium concentrations are recorded at 5-minute intervals. H. W . BERTRAM, M . W . LERNER, G. J. PETRETIC, E. S. ROSZKOWSKI, and C. J. RODDEN, U. S. Atomic Energy Commission, N e w Brunswick, N.J.
ARTHUR
FURST,
Stanford
Anal. Chem. 3 0 , 3 6 5 ( 1 9 5 8 )
Wet Ash Spectrochemical Method for Determination of Trace Metals in Petroleum Fractions
Copper metal powder can be successfully employed as a carrier-matrix for spectrochemical determination of vanadium, nickel, and iron in wet ash residues of petro leum fractions. As little as 0.05 p.p.m. of nickel and vanadium can be determined in a 10-gram sample. Techniques are given for both photographic and direct reading instruments. J O H N HANSEN and C. R. H O D G K I N S , Esso Research and Engineering Co., Linden, N. J. Anal. Chem. 3 0 , 3 6 8 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 5 4 ( 1 9 5 8 )
Photometric Determination of Chromium in Electronic Nickel
A method for photometric determination of 0.001 to 0.02% chromium in electronic nickel has been de veloped. Chromium is oxidized to hexavalent state. Nickel is removed in form of difficultly soluble ammonium perchlorate salt. Chromate is determined by diphenylcarbazide method. C. L. LUKE, Bell Telephone Laboratories, Inc., Murray Hill, N . J. Anal. Chem. 3 0 , 3 5 9 ( 1 9 5 8 )
Bromine Number of Propylene and Butylène Polymers
In determination of bromine numbers of propylene and butylène polymers of low molecular weight, elimination of mercuric chloride catalyst in titration solvent of ASTM electrometric method gives more reliable results than other ASTM methods. This modified method is also more accurate for types of olefins occurring in cracked gasolines. J. C. S. W O O D , Sun Oil Co., Marcus Hook, Pa. Anal. Chem. 3 0 , 3 7 2 ( 1 9 5 8 )
Volumetric Determination of Magnesium in Titanium
Magnesium can be determined in titanium sponge and other titanium products by titration with standard EDTA using Eriochrome Black Τ mixed with methyl red as indicator. Titanium and other interfering elements are separated by ammonium acetate treatment. Manganese interference is removed by sodium sulfide. M . J. MILES, W . J. MESIMER, and MAE ATKIN, Titanium Metals Corp. of America, Henderson, Nev. Anal. Chem. 3 0 , 3 6 1 ( 1 9 5 8 )
Influence of Olefin Structure on Bromine Number as Determined by Various Analytical Methods
Three ASTM methods of determining olefins by bromination have been critically surveyed. 45 API standard olefins were analyzed and relationship between structure type of olefin and bromine number was examined. It is concluded that modified electrometric method, which omits mercuric chloride catalyst, is best. E. H. UNGER, Socony Mobil Oil Co., Inc., Paulsboro, N . J. Anal. Chem. 3 0 , 3 7 5 ( 1 9 5 8 )
Determination of O x y g e n in Titanium. Modified Vacuum Fusion Apparatus and Platinum Bath Technique
An improved vacuum fusion apparatus for determination of oxygen in titanium incorporates an improved furnace section, a sample entry port, and an analytical system. Use of platinum bath results in simplified operation, giv ing fast and reliable oxygen determinations. 30 samples can be analyzed before opening system to atmosphere. S. J. BENNETT and L. C. C O V I N G T O N , Titanium M e t a l Corp. of America, Henderson, Nev. Anal. Chem. 3 0 , 3 6 3 ( 1 9 5 8 )
Determination of Alpha-Glycol Content of Epoxy Resins
A method for determination of α-glycol groups in epoxy resins uses chloroform as the solvent and an alcoholic solution of a quaternary ammonium periodate as reagent. Method gives accurate results with pure glycols and is sensitive to small concentrations of glycol groups in epoxy resins. G . A. STENMARK, Shell Development Co., Emeryville, Calif. Anal. Chem. 3 0 , 3 8 1 ( 1 9 5 8 )
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BREIFS Nature of Bindschedler's Green. Analysis of Hydrazo Compounds
Preparation for
Automatic Unit for Determination of Volatile Matter in Coal, Coke, and Char
Bindschedler's Green, when prepared by a modification of Wieland's method, is stable over long periods of time and generally gives clear, colorless end points in titra tions with titanium trichloride. Simple method is given for preparing red form of Bindschedler's Green. Struc tures of both forms are given from analytical data.
An automatic mechanical lowering device has been de veloped for lowering crucible at uniform rate into hot furnace in ASTM method for volatile content of coal, coke, or char. Apparatus permits close control of heat ing, is sufficiently flexible to be adapted to a variety of materials, and automatically controls entire operation.
H. J. SHINE, R. L. SNELL, and J. C. TRISLER, Texas Technological College, Lubbock, Tex.
R. P. HENSEL and S. A. JONES, Pittsburgh Consolidation Coal Co., Library, Pa.
Anal. Chem. 3 0 , 3 8 3 ( 1 9 5 8 )
Anal. Chem. 3 0 , 4 0 2 ( 1 9 5 8 )
Determination of Zinc and Separation from Ashed Biological Material Improved lodometric Method of Analysis for teriButyl Peresters
Wheeler method for iodometric analysis of peroxides has been improved by use of 0.002% ferric chloride hexahydrate in acetic acid as solvent, thus making it applicable to analysis of both aliphatic and aromatic tert-hatyl peresters. Reaction times are shortened to 5 to 10 minutes. L. S. SILBERT and DANIEL SWERN, Laboratory, Philadelphia 1 8 , Pa.
Eastern
Regional
Research
Microgram amounts of zinc in ashed biological materials can be determined colorimetrically by using 4-chlororesorcinol. Zinc is separated from interfering cations by extraction of zinc diethyldithiocarbamate with chloro form and re-extraction of the zinc with 0.16M hydro chloric acid. Zinc-4-chlororesorcinol complex obeys Beer's law in range of 0.1 to 5 p.p.m. of zinc. J. A. STEWART and J. C. BARTLET, Department of National Health and Welfare, Ottawa, Canada Anal. Chem. 3 0 , 4 0 4 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 8 5 ( 1 9 5 8 )
Rapid and Precise Carbon-Hydrogen Determination. Automatic Macrocombustion Apparatus Critical Analysis of Methods for Measurement of Pregnane-3-a,17-a, 20-a-Triol in H u m a n Urine
Three methods for measurement of pregnanetriol in human urine are critically compared. Method depend ing on unique sulfuric acid chromogens after chroma tography shows high degree of specificity. Oxidation to acetaldehyde with periodic acid is also good. Chromic acid oxidation gives higher results. A. M . B O N G I O V A N N I and W . R. EBERLEIN, University of Pennsylvania, Philadelphia, Pa.
An automatic combustion apparatus permits rapid and precise macrodetermination of carbon and hydrogen with minimum of operator training and attention. A manometer control mechanism monitors pressure in combustion tube and controls the heater and cooling air blast used to maintain desired rapid sample vaporization rate. Combustion cycle requires about 20 minutes. T. T. WHITE, V. A. CAMPANILE, E. J. A G A Z Z I , L. D. TeSELLE, P. C. TAIT, F. R. BROOKS, and Ε. D. PETERS, Shell Development Co., Emeryville, Calif. Anal. Chem. 3 0 , 4 0 9 ( 1 9 5 8 )
Anal. Chem. 3 0 , 3 8 8 ( 1 9 5 8 )
Separation of 1 3 2 ° to 1 3 8 ° C. Fraction of Petroleum. Bicycloparaffins in Gasoline Fraction of Petroleum
The branched paraffin-cycloparaffin portion of the representative petroleum of API Research Project 6, normally boiling between 132° and 138° C , has been separated by regular and azeotropic distillation to give concentrates of branched paraffins, monocycloparaffins, and bicycloparaffins. Two additional bicycloparaffins have been isolated and identified.
Use of Chlorine in the Attack of Noble Metals. Quantitative Recovery of Micro Amounts of Platinum, Ruthenium, and Osmium
Dry chlorination is applied quantitatively to dissolution of micro amounts of osmium, ruthenium, and platinum in resistant precious metal alloys. Relatively volatile osmium chlorides are retained by passing chlorine stream into receivers containing hydrochloric acid saturated with sulfur dioxide. Ruthenium is converted entirely to soluble chlorides when hotter parts of reaction tube are coated with fused sodium chloride. A. D. WESTLAND and F. E. BEAMISH, University of Toronto, Toronto Ontario, C a n a d a
B. J. MAIR, P. E. EBERLY, Jr., N . C. KROUSKOP and F. D. ROSSINI, Carnegie Institute of Technology, Pittsburgh, Pa. Anal. Chem. 3 0 , 3 9 3 ( 1 9 5 8 )
Analysis of Phenol-Containing Volatile Oils
Phenol-containing volatile oils can be analyzed by non aqueous titrimetry with sodium methoxide in benzenemethanol as titrant. Solvents are dimethyl formamide, acetonitrile, and ethylenediamine. Platinum and calo mel electrode system is employed. Procedure offers a number of advantages over classical extraction procedure with alkali solution. M . I. BLAKE, North Dakota Agricultural College, Fargo, N . D. Anal. Chem. 3 0 , 4 0 0 (1 9 5 8 )
Anal. Chem. 3 0 , 4 1 4 ( 1 9 5 8 )
Certain Rare Earths in Purified Thorium and Uranium Preparations. Chemical Isolation and Spectrographic Determination
Microgram quantities of rare earths can be quantitatively separated from thorium nitrate dodecahydrate or uranyl nitrate hexahydrate by dissolving salt in ether-nitric acid mixture, stirring with cellulose, and filtering. Rare earths are retained on cellulose and removed with aqueous nitric acid (pH 2). Rare earth solution is puri fied by TTA extraction. An aliquot is analyzed spectrographically. CYRUS FELDMAN and J. Y. Laboratory, O a k Ridge, Tenn.
ELLENBURG,
Oak
Ridge
National
Anal. Chem. 3 0 , 4 1 8 ( 1 9 5 8 1
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BRIEFS Microdetermination of Zirconium in Sulfuric Acid Solutions with Pyrocatechol Violet
Coulometric Reduction of Oxides on Tin Plate
The blue color of zirconium-pyrocatechol violet complex is used in a very sensitive colorimetric method for zir conium in dilute sulfuric acid solutions. Molar absorbance index of complex is 32,600 at 650 m/i. It conforms to Beer's law up to 2 7 zirconium per ml. Aluminum, titanium, and vanadium interfere seriously. J . P. Y O U N G , J . R. FRENCH, a n d J . C. WHITE, O a k Ridge N a t i o n a l L a b o r a t o r y , O a k Ridge, Tenn.
In coulometric reduction of oxides on tin-plate surfaces, quantity of oxides measured is influenced by composi tion of electrolyte, oxygen dissolved in electrolyte, and current density. It is depenent on pH and buffering capacity of the electrolyte. R. P. FRANKENTHAL, T. J. BUTLER, and R. T. DAVIS, Jr., United States Steel Corp., Monroeville, Pa. A n a l . Chem. 3 0 , 4 4 1 ( 1 9 5 8 )
A n a l . Chem. 3 0 , 4 2 2 ( 1 9 5 8 )
Continuous Sampling and Ultramicrodetermination of Nitrogen Dioxide in Air
A simple, convenient method is given for continuous sampling and ultramicrodetermination of nitrogen di oxide in urban atmospheres. Air is aspirated through 0.1JV alkali and absorbed nitrogen dioxide is determined colorimetrically as the azo dye. Sulfur dioxide which reduces the color is removed by oxidation with hydrogen peroxide.
Infrared Identification of Some Sulfur Derivatives of Long-Chain Fatty Acids
Infrared absorption spectra of some long-chain fatty acid derivatives containing sulfide, sulfoxide, and sulfone groups have been studied to determine effects of such substitutions on characteristic bands of fatty acids. Closely related sulfur derivatives of fatty acids can be distinguished by studying the 1350-1180-cm. _1 region of solid-state spectra.
Air
HEINO SUSI, N . H. K O E N I G , W . E. PARKER, a n d DANIEL SWERN, U. S. Department o f Agriculture, Philadelphia 1 8 , Pa.
A n a l . Chem. 3 0 , 4 2 6 ( 1 9 5 8 )
A n a l . Chem. 3 0 , 4 4 3 ( 1 9 5 8 )
M . B. JACOBS and SEYMOUR HOCHHFISER, Pollution Control, N e w York 3 5 , Ν . Υ.
Department
of
Rapid Quantitative Determination of Sulfur in Organic Compounds
A simple procedure for determination of sulfur in organic compounds uses Schoniger method of burning sample in oxygen-filled flask. After absorption of combustion products in 6% hydrogen peroxide, analysis is com pleted either by titration with sodium hydroxide or precipitation as barium sulfate. Precision of method is ± 1 % using samples containing 5 to 10 mg. of sulfur.
Determination of Equivalent Weight of Esters and Halides with Cation Exchange Resins
A new method for determining equivalent weights of phosphorus or sulfur esters and alkyl halides is devised. Reaction of these with ethanolamine forms salts which are passed through cation exchange resins (in hydrogen form). Free acid formed is titrated directly with alkali.
IHOR LYSYJ a n d J . E. ZAREMBO, Food Machinery and Chemical Corp., Princeton, N. J .
W . H. B A L D W I N a n d C. E. HIGG1NS, O a k Ridge National L a b o r a t o r y , O a k Ridge, Tenn.
A n a l . Chem. 3 0 , 4 2 8 ( 1 9 5 8 )
A n a l . Chem. 3 0 , 4 4 6 ( 1 9 5 8 )
Field Sampling and Analysis of Micro Quantities of Sesquimustard in Presence of Mustard
Micro quantities of mustard and sesquimustard can be determined in presence of each other by analysis by two different colorimetric techniques. From simultaneous equations derived from slopes of colorimetric calibration curves, quantity of each can be estimated. ABRAHAM KOBLIN, A r m y Chemical Center, M d . A n a l . Chem. 3 0 , 4 3 0 ( 1 9 5 8 )
Microdetermination of Chromium with 1,5-Diphenylcarbohydrazide
Effects of pH, redistillation of water, nature and concen tration of organic solvent, concentration and quality of reagent, age of stock solutions, order of mixing, tempera ture, and ionic strength in determination of chromium (VI) with 1,5-diphenylcarbohydrazide have been studied. Most important variables are quality of solid reagent and quality of reagent stock solutions. T. L. ALLEN, University o f C a l i f o r n i a , Davis, Calif. A n a l . Chem. 3 0 , 4 4 7 ( 1 9 5 8 )
Photometric Determination of Zinc Oxide in Rubber Products. Absorptiometric and Turbidimetric Methods Using Sodium Diethyl Dithiocarbamate
Precipitation of zinc diethyl dithiocarbamate from weakly alkaline solution is basis of two methods for determina tion of zinc oxide in rubber. In one, zinc complex is extracted with ether and absorbance measured in ultra violet. Alternatively, absorbance of a colloidal aqueous suspension of precipitate is measured. Both dry and wet ashings are used with samples of 1 to 15 mg. K. E. KRESS, The Firestone Tire &. Rubber Co., A k r o n , O h i o A n a l . Chem. 3 0 , 4 3 2 ( 1 9 5 8 )
Indirect Absorptiometric Determination of Cyanide
Indirect absorptiometric method for determination of cyanide has been modified to extend its range and remove sulfide interference. Method is applicable from 0.15 to 9.0 7 of cyanide per 3 ml. A differential technique is used below 1.5 7 of cyanide. O . A. OHLWEILER a n d J. O . MEDITSCH, Escola d e Engenharia, Porto A l e g r e , R.G.S., Brazil A n a l . Chem. 3 0 , 4 5 0 ( 1 9 5 8 )
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