A C BRIEFS Highlights of the scientific and technical articles in this issue
Controlled Potential Coulometry in Fused Lithium Chloride-Potassium Chloride Eutectic A controlled-potential coulometric technique determines zinc(II), c a d m i u m ( I I ) , and nickel(II) in fused lithium chloride—potassium chloride eutectic. Zinc and cadmium are stripped from the bismuth electrode at suitable poten tials, and nickel is determined by controlled potential strip ping of the predeposit from a platinum gauze electrode. J . D. V A N N O R M A N , Ν . Υ.
Broolchaven N a t i o n a l
Laboratory,
Upton,
Determination of Lead and Other Heavy Metals in Urine by Atomic Absorption Spectroscopy Atomic absorption spectroscopy is used for the deter mination of lead and other heavy metals in urine samples. The metals are complexed with ammonium pyrrolidine dithiocarbamale and extracted with methyl-n-amyl ketone. Procedural details are given for lead, mercury, bismuth, nickel, zinc, and cadmium. J . B. W I L L I S , C . S . I . R . O . Chemical bourne, Australia
A voltammeric reduction wave technique is devised for determining acids. The reduction wave occurs at a rotat ing platinum electrode in liquid ammonia solution of ammonium salts at —77° C. T h e wave results from the reduction of ammonium ions. Data obtained are used to elucidate solution equilibria of liquid ammonia solutions. R. N . H A M M E R and J . J . L A G O W S K I , M i c h i g a n State University, East Lansing, M i c h . A n a l . C h e m . 3 4 , 597 ( 1 9 6 2 )
Laboratories,
Mel
A n a l . C h e m . 34, 614 ( 1 9 6 2 )
A n a l . C h e m . 34, 5 9 4 ( 1 9 6 2 )
Voltammetric Reduction of Acids in Liquid Ammonia
Research
Spectrophotometric Determination of Tantalum in Iron, Steel, and Niobium M e t a l The tantalum content of iron, steel, and niobium samples is determined by spectrophotometric analysis. The sample is dissolved in sulfuric acid and the tantalum complexed with malachite green in the presence of hydrofluoric acid. The complex is extracted with benzene and its maximum absorbance measured at 635 ναμ. Y A C H I Y O KAKITA Sendai, J a p a n
and H I D E H I R O
GOTO,
Tohoku
University,
A n a l . C h e m . 34, 618 ( 1 9 6 2 )
Kinetic Analysis of Mixtures by the Method of Proportional Equations A proportional equation procedure is proposed for the kinetic analysis of mixtures which circumvents the limita tions of existing procedures. T h e proposed procedure is applicable to all first- and pseudo-first-order reactions, both simple and complex. The use of variables other than time for kinetic analysis is discussed. R. G . G A R M O N and C . N . REILLEY, University of N o r t h C a r o l i n a , Chapel Hill, N . C . Anal. Chem. 34, 600 (1962)
Analysis of High-Purity Chromium High-purity chromium is analyzed for impurities by chemical-spectrographic technique. T h e sample is dissolved in acid and chromium removed as chromyl chloride by volatilization. T h e residue is analyzed spectrographically for metals such as iron, nickel, aluminum, manganese, titanium, vanadium, magnesium, and copper. R. E. H E F F E L F I N G E R , E. R. BLOSSER, O . E. PERKINS, and W . M . H E N R Y , Battelle M e m o r i a l Institute, Columbus, O h i o A n a l . C h e m . 34, 621
lron-55 X-Ray Absorption Analysis of Organ ically Bound Chlorine Using Conventional Pro portional Counting Facilities An iron-55 x-ray absorption technique is modified to use conventional proportional counting facilities for deter mining bound chlorine in organic materials. T h e tech nique is based on the decay of iron-55, by K-electron capture, to stable manganese-55 with the attendant emis sion of soft-K-line x-rays. The method is applied to technical grade and finished products. L. H . G R I F F I N , Shell C h e m i c a l C o . , Deer Park, Tex. A n a l . C h e m . 34, 6 0 6 ( 1 9 6 2 )
Solvent Extraction Separation photometric Determination of Iridium
(1962)
and Spectro Rhodium and
Rhodium and iridium in mixtures are separated by solvent extraction and determined spectrophotometrically. Rho dium is selectively complexed with tin (II) bromide and extracted with isopentyl alcohol. T h e maximum absorb ance is measured at 429 ταμ. Iridium, in the aqueous phase, is determined at 403 m/x. G . G . TERTIPIS and F. E. Toronto, O n t . C a n a d a
BEAMISH,
University
of
Toronto,
A n a l . C h e m . 34, 623
Determination of Niobium and Tantalum in Minerals, Ores, and Concentrates Using Ion Exchange An ion exchange procedure is used for the separation and subsequent determination of niobium and tantalum in ores, minerals, and concentrates. T h e sample is dissolved in hydrochloric-nitric acid solution and separated on a Dowex-1 column. T h e elements are eluted and deter mined gravimetrically. SILVE K A L L M A N N , H A N S O B E R T H I N , and ROBERT L I U , Ledoux & C o . , Teaneclc, N . J . A n a l . C h e m . 34, 609 ( 1 9 6 2 )
(1962)
Quantitative Radiochemical Determination Molybdenum-99 by Solvent Extraction
of
The rapid quantitative separation of molybdenum-99 from fission product is accomplished by solvent extraction. T h e molybdenum-99 is extracted with α-benzoin oxime in chloroform, and the chloroform layer is removed and counted in a gamma-ray scintillation well counter. L E O N W I S H , U . S. N a v a l Radiological Defense Laboratory, San Francisco 24, C a l i f . A n a l . C h e m . 34, 625 ( 1 9 6 2 )
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BRIEFS Determination of Tin and Molybdenum in Nu clear Reactor and Other Materials. Extraction and Spectrophotometric Determination with 8-Quinolinol A rapid and accurate extraction-spectrophotometric pro cedure determines molybdenum and tin in reactor and other materials. Molybdenum and tin are complexed with 8-quinolinol. T h e molybdenum is extracted with chloro form and measured at 385 τημ. Ammonium chloride is added and the tin complex extracted and measured at 385 m/i. A . R. EBERLE and M . W . LERNER, A E C N e w Brunswick Labora tory, New Brunswick, N . J . A n a l . C h e m . 34, 627 ( 1 9 6 2 )
Spectrophotometric Determination with Ethylenediamine
of
Copper
The copper content of ores and alloys is determined by a spectrophotometric method. T h e sample is dissolved in acid solution and the Cu ++ ion complexed with ethylenedi amine. T h e chelates formed give a stable, blue aqueous solution with a maximum absorbance at 540 τημ. The method obevs Beer's Law in the concentration range of 20 to 1000 plp.m.
Effect of Preheater Contamination on Gas Chromatographic Analysis of Strongly Adsorbed Substances The preheater section of a chromatograph must be main tained free of carbon deposit when strongly adsorbed materials are analyzed. Such carbon deposits lead to low detector responses and false peaks. T h e effects are most noticeable with acids and amines, and to some extent with alcohols and ketones. E. D. S M I T H and A . B. G O S N E L L , University of Arkansas, Little Rock, A r k . A n a l . C h e m . 34, 646 ( 1 9 6 2 )
Separation of Organo- and OrganobromoArsenic Compounds by Gas-Liquid Chromatography The separation and quantitative analysis of organo- and organobromo arsines is accomplished by gas-liquid chro matography. A linear function exists between the log of the retention time and the boiling point or molecular weight of the substance. B. J . G U D Z I N O W I C Z C o r p . , Everett, Mass.
and H . F. M A R T I N ,
Monsanto
Research
A n a l . C h e m . 34, 648 ( 1 9 6 2 ) E. A . T O M I C and J . L. B E R N A R D , E. I. du Pont de Nemours & C o . , W i l m i n g t o n 98, D e l . A n a l . C h e m . 3 4 , 632 ( 1 9 6 2 )
Gas-Liquid Chromatography of Some Methyl ated Mono-, Di-, and Trisaccharides Use of Organic Solvents in Limited Area Flame Spectrometry Limited area flame spectrometry, using organic solvents, provides higher excitation energies b3r utilizing chemiluminescence in the reaction zone. This technique ex tends the scope of flame photometry. Principle con sideration is given to t h e difference in distribution of emission in oxy-hydrogen flame when atomizing aqueous and organic solutions.
Mixtures of methylated mono-, di-, and trisaccharides are separated by gas-liquid chromatography. Primary concern is with the operating variables that affect separa tion. Results indicate that the technique is primarily qualitative, but possessing good possibility for quantita tive analysis. M I L D R E D G E E and H . G . W A L K E R , Jr., W e s t e r n Regional Research Laboratory, A l b a n y , C a l i f . A n a l . C h e m . 34, 650 ( 1 9 6 2 )
B. E. BUELL, Union O i l C o . of C a l i f o r n i a , Union Research Center, Brea, C a l i f . A n a l . C h e m . 34, 635 ( 1 9 6 2 )
Spectrophotometric Determination of as Reduced Moiybdoniobic Acid
Niobium
A spectrophotometric procedure is used to determine small quantities of niobium in steel. Niobium is com plexed with sodium molybdate and resulting molybdoniobate reduced with chlorostannous acid. T h e in tensity of the blue solution formed is measured at 725 ταμ.
Separation and Analysis of Mixtures of Hydro carbon and Inorganic Gases by Gas Chroma tography A fast and accurate gas chromatographic procedure is developed for the separation and determination of hydro carbons and certain inorganic gases in mixtures. The or ganic and inorganic constituents of a sample are de termined in a single analysis through the use of multiple columns. The procedure is applied successfully in the analysis of flue gases.
J . C . G U Y O N , G . W . W A L L A C E , Jr., with M . G . M E L L O N , Purdue University, Lafayette, I n d . Anal. Chem. 34, 640 (1962)
G. J. CVEJANOVICH, Netherlands Antilles
Determination of Radioactive Calcium by Liquid Scintillation Counting
An Instrument for On-Stream Stripping and Gas Chromatographic Determination of Dissolved Gases in Liquids
Radioactive ealcium-45 is determined by a liquid scintilla tion counting technique which affords low background and high efficiency. T h e calcium is precipitated as the oxalate which is converted to the nitrate form. Calcium-45 nitrate is counted in a system of toluene-ethyl alcohol—ethylene glycol—nitric acid. M A R L E N E S A R N A T and H E N R Y J E F F A Y , University of Illinois, Chicago, III. A n a l . C h e m . 34, 643 ( 1 9 6 2 )
Lago O i l & Transport C o . , Ltd., A r u b a , A n a l . C h e m . 34, 654
(1962)
A multiple spinning-disk stripper is used in conjunction with a gas chromatograph for the analysis of dissolved gases. T h e apparatus is designed to provide an on-stream monitoring of dissolved gases in water. T h e device gives simultaneous data for all gases in a system. D. D. W I L L I A M S and R. R. M I L L E R , U. S. N a v a l Research Laboratory, Washington 25, D. C . A n a l . C h e m . 34, 657 ( 1 9 6 2 )
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i=i--"=i^H Paper Chromatographic Analysis of the Disaccharide Fraction of 60 Dextrose Equivalent Acid Hydrolyzed Corn Syrup. A Study of the Sep aration of Eleven Glucodisaccharides The components of sixty dextrose equivalent acid hy drolyzed corn syrup are separated, identified, and quan titatively estimated by paper chromatography. From chromatographic data on glucodisaccharides with pyranose combinations it was determined that the corn syrup hydrolyzate contains eight such compounds. t . D. O U G H , Clinton Corn Processing Co., Clinton, Iowa Anal. Chem. 34, 660 (1962)
Determination of Chloroboranes, Diborane ( 6 ) , and Hydrogen Chloride by Gas Chroma tography Λ gas chromatographic procedure is developed for the determination of chloroborane intermediates and the products of the hydrogenolysis of boron trichloride. The analytical resolution of all the components is accomplished by using several low temperature columns. H . W . MYERS and R. F. PUTNAM, Stauffer-Aerojet Laboratories, Nimbus, Calif. Anal. Chem. 34, 664 (1962)
Separation of 2,4-Dinitrophenylhydrazone Derivatives of Aliphatic Monocarbonyls into Classes on Magnesia 2,4-Dinitrophenylhydrazone derivatives of aliphatic mono carbonyls are separated into classes by separation on a magnesia-Celite column. The compounds are eluted in a class sequence using various mixtures of chloroform and hexane. Characteristic colors for each class on the adsorbent make identification possible.
Laboratory Evaluation of Sulfur Dioxide Meth ods and the Influence of Ozone-Oxides of Nitro gen Mixtures Three wet chemical methods for determining atmospheric sulfur dioxide are evaluated. Over a concentration range from 0.3 to 3.78 mg. per cubic meter, the acidimétrie and spectrophotometric methods gave comparable results, while the iodometric procedure gave lower results. All three procedures are affected by ozone-oxides of nitrogen mixtures. F. P. TERRAGLIO and R. M. MANGANELLI, Rutgers, the State University, New Brunswick, N. J . Anal. Chem. 34, 675 (1962)
A Rapid Automatic Microdetermination of Nitrogen A micronitrogen analyzer is constructed for the rapid, automatic determination of trace amounts of nitrogen. A sample may be analyzed for nitrogen within 15 minutes. Structural design and operating procedures are given. L. DORFMAN, R. OECKINGHAUS, F. ANDERSON, and G. I. ROBERTSON, CIBA Pharmaceutical Co., Summit, N. J . Anal. Chem. 34, 678 (1962)
Determination of Azides in Organic Solvents Azides in organic solvents are determined by precipitating the azide as silver azide, filtering, and washing to remove all traces of solvent. The precipitate is oxidized with excess eerie ion and back-titrated with ferrous ammonium sulfate. E. L. GROVE, R. S. BRAMAN, H. F. COMBS, and S. B. NICHOLSON, Armour Research Foundation, Chicago 16, III.
D. P. SCHWARTZ, O. W . PARKS, and MARK KEENEY, U. S. Department of Agriculture, Washington 25, D. C.
Anal. Chem. 34, 682 (1962)
Anal. Chem. 34, 669 (1962)
Paper Chromatographic Analysis of Urethan Derivatives of Saturated Aliphatic Alcohols A series of saturated primary alcohols, Ci to Ci2, are separated by paper chromatographic procedure. The alcohols are converted to a urethan derivative and chromatogiaphed. Lower members of the series respond best as the /H-nitrophenyl derivatives, while the o-nitrophenyl derivatives were best for the Co to C12 members.
Fluorescence azaindoles
Properties
of
Mono-
and
Poly-
An investigation is made of the fluorescence properties of a series of indoles in which one, two, or three methine carbons have been replaced by a isoelectric nitrogen atom. The relative fluorescence intensities are calculated and examined in relation to the absorptivities and to the frequency difference between the absorbed and emitted beams.
J . A. ATTAWAY, R. W . WOLFORD, and Θ. E. ALBERDING. Florida Citrus Commission, Lake Alfred, Fla., and G. J . ED WARDS, University of Florida Citrus Experiment Station, Lalte Alfred, Fla. Anal. Chem. 34, 671 (1962)
T. K. ADLER, University Francisco, Calif.
Simultaneous Microdetermination of Carbon, Hydrogen, and Boron in Organoboranes
Trace Analysis for Basic Nitrogen in Gasoline
of California
Medical
Center, San
Anal. Chem. 34, 685 (1962)
A micro-method is developed for the simultaneous de termination of carbon, hydrogen, and boron in organo boranes. The sample is combusted, and hydrogen and carbon are determined by conventional means. Boron in the residue is dissolved in water and the boric acid formed is titrated with sodium hydroxide.
Gasoline samples are analyzed for basic nitrogen content by an ion exchange technique. The basic nitrogen compounds in gasoline are pyridines and quinolines. After separation the basic nitrogen is determined from the molar absorptivity of the compounds at 260 πιμ. Differential determinations are made from absorption measurements at 300 τημ.
R. C. RITTNER and ROBERT CULMO, Olin Mathieson Chemical Corp., New Haven, Conn. Anal. Chem. 34, 673 (1962)
L R. SNYDER and B. E. BUELL, Union Oil Co. of Calif., Brea, Calif. Anal. Chem. 34, 689 (1962) VOL. 34, NO. 6, MAY 1962
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BRIEFS Spectrophotometric Titrations of Carbon Diox ide, Bicarbonate, and Carbonate Solutions An alkalimetric titration technique for determining carbon dioxide solutions uses the enzyme carbonic anhydrase. The end point is measured spectrophotometrically from the ultraviolet absorption of carbonate ions. This type of indicator eliminates blank correction and indicates better precision than conventional indicators. A. L. UNDERWOOD and L. H. H O W E I I I , Emory University, Atlanta 22, Ga. Anal. Chem. 34, 692 (1962)
Investigation of the Nature of Free Radicals in Petroleum Asphaltenes and Related Substances by Electron Spin Resonance The structure of native petroleum asphaltenes is investi gated by electron spin resonance. T h e data obtained are consistent with the theory that the free radicals in petro leum asphaltenes are associated with a nonlocalized π system of electrons stabilized by resonance. Several de tailed proposed structures are outlined. T. F. YEN and J . G. ERDMAN, Mellon Institute, Pittsburgh, Pa., and A. J . SARACENO, Gulf Research & Development Co., Pittsburgh, Pa. Anal. Chem. 34, 694 (1962)
Determination of Iodide in Lead Telluride Semi conductor A spectrophotometric method is devised for determining iodide in lead telluride semiconductors. T h e sample is dissolved in nitric acid and t h e lead iodide is converted to iodine by oxidation. T h e iodine is extracted with o-xylene and measured spectrophotometrically at 495 μ. LOUIS SILVERMAN, Atomics International, Canoga Park, Calif. Anal. Chem. 34, 701 (1962)
Jhftfew COURTAULD MODELS
A Simple Atmospheric Carbon Dioxide Analyzer An instrument substantially lower in cost and comparable in performance with a nondispersive infrared analyzer has been developed to measure carbon dioxide at atmospheric concentrations. T h e device uses fine marble chips sus pended in continually aerated distilled water. Equilibrium p H is measured by an expanded-scale p H meter. T h e instrument is accurate and suitable for routine carbon dioxide measurements. Results can be recorded. J . P. LODGE, Jr., E. R. FRANK, and JAMES FERGUSON, Robert A. Taft Sanitary Engineering Center, Cincinnati 26, Ohio Anal. Chem. 34, 7C2 (1962)
An Efficient Still for Milligram Samples of HighBoiling Materials A still was constructed for the separation of milligram samples of high-boiling materials. The apparatus utilizes the principle of rectification in a temperature gradient. A silicon film to reduce wettability prevents remixing of the liquid distillates. T h e still is used in the separation of hydrocarbons, resins, low molecular weight asphaltenes, and other organic chemicals. MAX BLUMER, Shell Development Co., Houston, Tex. Anal. Chem. 34, 704 (1962) Correction Controlled-Potential Coulometric Titration of Antimony
I n t h e brief of the above-entitled paper, it was incorrectly stated that the titrations were carried out in an acetic acid-hydrochloric acid electrolyte. This should have read tartaric acid-hydrochloric acid electrolyte. L. B. DUNLAP and W . D. SHULTS, Oak Ridge National Labora tory, Oak Ridge, Tenn. Anal. Chem. 34, 499 (1962)
have found them very useful for demon strating carbohydrate configuration and helix configuration in polypep tide structures." "Most importantly, however, we hare been using them in connection with lectures and demonstrations of nucleotide and nucleic acid structure and chemistry . . ." —Dept. of Biochemistry (name provided on request.)
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THE
Ealing
CORPORATION
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VOL 34, NO. 6, MAY 1902
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