AC
BRIEFS Highlights of the contributed articles in this issue
Adventures in Instrumentation Miiller, in the Beckman Award address, traces the course of instrumentation in analytical chemistry from early gadgeteering to present needs. Some of his observations are: T h e r e exists a unified and general approach to the instrumentation of any p h e n o m e n a ; there is need for more pure, uncommitted research in rare and obscure phenomena; there is need to train instrument scientists; and instrumentation is largely responsible for our technological supremacy. R. H. MÜLLER, Los Alamos Scientific Laboratory, Los Alamos, Ν. Μ. Anal. Chem. 2 9 , 111 8 ( 1 9 5 7 )
General Procedure for Setting up Infrared Differential Analyses of Multicomponent Mixtures
Separation of Uranium from Thorium, Bismuth, and Ores with Tributyl Phosphate. Spectrophotometric Determination with 8-Quinolinol Microgram quantities of uranium in thorium, bismuth, and a variety of ores can be separated by extraction with tributyl phosphate. W h e n thorium is present, extraction is made from 7 Λ'hydrochloric acid, otherwise from 4.7Ν nitric acid. Uranium is determined spectrophotomerrically with 8-quinolinol. A. R. EBERLE and M. W . LERNER, U.S. Atomic Energy New Brunswick, N J .
Commission
Anal. Chem. 2 9 , 1 1 3 4 ( 1 9 5 7 )
Photometric Determination of Silicon in Steel A rapid and accurate photometric method for routine determination of silicon in steel uses the molybdenum blue complex with ferrous i o n s of the sample as the reducing agent. A compensating blank is used for reference.
Precision of infrared analyses of multicomponent mix tures can be greatly improved by differential spectro photometry using wire screens as references. A se quence of steps for straightforward calibration for differential analyses of multicomponent mixtures is illustrated in detail by reference to an analysis of a sixc o m p o n e n t Ci hydrocarbon gas.
W . F. SANDERS and C. H. CRAMER, United Engineering and Foundry Co., Vandergrift, Pa.
J. A. PERRY and G . H. BAIN, Standard Oil Co. (Indiana), Whiting, Ind.
Anal. Chem. 2 9 , 1 1 3 9 ( 1 9 5 7 )
Anal. Chem. 2 9 , 1 1 2 3 ( 1 9 5 7 )
Infrared Spectrophotometric Analysis of Fractional Milligram Quantities of Solids A new evacuable die is used to form rectangular potas sium b r o m i d e pellets only slightly larger than the sample beam of the infrared spectrophotometer. Body of die containing formed pellet is mounted directly in the instrument. Qualitative and quantitative analysis of fractional milligram-size samples can be carried out with this unit. J. J. KIRKLAND, E. I. du Pont de Nemours & Co., Inc., Wilmington, Del. Anal. Chem. 2 9 , 1 1 2 7 ( 1 9 5 7 )
Spectrophotometric Determination of Fluorine in Rocks In a simple and accurate method for determination of fluorine in r o c k s , sample is decomposed with sodium peroxide. After precipitation of silica and alumina, fluorine is separated by steam distillation and determined in an aliquot of the distillate by spectrophotometric titration with thorium in presence of a dye, SPADNS. R. P. HOLLINGWORTH, University of Durham, Durham, England Anal. Chem. 2 9 , 1 1 3 0 ( 1 9 5 7 )
Direct-Reading Spectrochemical Analysis of Nonmetallics Used in the A l u m i n u m Industry Minor impurities in alumina and in carbon materials can be determined readily by a direct-reading spectrometer in conjunction with straightforward direct-current arc excitation of an alumina-carbon mixture. Other deter minations can be made by the same procedure by varying p r o p o r t i o n s of sample, alumina, and graphite. For determinations in bauxite, copper oxide is used as in ternal standard. R. H. BLACK and P. E. LEMIEUX, Aluminium Laboratories, Ltd., A r v i d a , Quebec, Canada Anal. Chem. 2 9 , 1141 ( 1 9 5 7 )
X-Ray Diffraction Powder Data for Some Copper N-Alkylsalicylaldimine Chelates X-ray diffraction p o w d e r data are presented for 11 copper chelates derived from straight-chain primary amines. Data permit identification of unsubstituted straight-chain primary amines containing from one to 14 carbon atoms. R. G . CHARLES and W . D. J O H N S T O N , Westinghouse Laboratories, Churchill Borough, Pittsburgh 3 5 , Pa.
Research
Anal. Chem. 2 9 , 1 1 4 5 ( 1 9 5 7 )
VOL. 2 9 , N O . 8 , AUGUST 1 9 5 7
·
7
A
BRIEFS Comparative V a l u e of X - R a y Diffraction and Infrared Spectrophotometry in Identifying Certain Sterols and Their Digitonides
Sterols in the C27 to C29 series can be easily differentiated by x-ray diffraction powder methods, but cannot be identified by infrared spectrophotometry. Sterol digi tonides cannot be identified by either method. X-ray diffraction definitely establishes sterol digitonides as chemical compounds.
T w o Techniques for Paper Chromatography
A method is described by which small amounts of crude drug can be extracted, the alkaloids of the extract sepa rated on paper and eluted, and the eluates quantitatively assayed. D. I. FRENCH and M. R. G I B S O N , State College of Washington, Pullman, Wash. Anal. Chem. 2 9 , 1 1 6 6 ( 1 9 5 7 )
W . T. BEHER, JONATHAN PARSONS, and G . D. BAKER, Henry Ford Hospital, Detroit 2 , Mich. Anal. Chem. 2 9 , 1 1 4 7 ( 1 9 5 7 )
Determination of Phenolic Glycosides and Aglycones on Paper Chromatograms Significance of pH in Determination of Vanillin by Ultraviolet Absorption
Study of ultraviolet absorption of aqueous solutions of vanillin as a function of pH shows a dissociation constant for vanillin of 7.3. Full basic form is found above pH 9.6 and full acid form below 5. Absorption maximum for basic form occurs at 347 πΐμ. Basic solutions are stable D. T. ENGLIS and L. A. WOLLERMANN, University of Illinois, U r b a n a , III.
Small amounts of phenols and phenolic glycosides present in enzymic digests can be accurately determined by separation by paper partition chromatography. Chromatogram is sprayed with diazotized />-nitroaniline. Spots are cut out and eluted with potassium hydroxide in aqueous methanol and absorbance is measured. J. B. PRIDHAM, Institute of Paper Chemistry, Appleton, Wis. Anal. Chem. 2 9 , 1 1 6 7 ( 1 9 5 7 )
Anal. Chem. 2 9 , 1 1 5 1 ( 1 9 5 7 )
Analyses of a Chromatographic Fraction of Organic Extracts of Soils
Chromatographic, infrared, and mass spectrometric methods are used for qualitative and semiquantitative analyses of benzene-methanol extracts of soils and especially of soil waxes. Types of acids and alcohols that form the wax esters are determined by converting esters to saturated hydrocarbons which are analyzed mass spectrometrically. Methods can be used for analysis of other complex organic mixtures. W . G . MEINSCHEIN and G. S. KENNY, Magnolia Petroleum Co., Dallas, Tex.
Gravimetric Determination of Boron. as Nitron Tetrafluoborate
Precipitation
Boron can be determined gxavimetrically by conversion of boric acid to tetrafluoboric acid and precipitation of this with the organic reagent, nitron. Distillation is not necessary and fluoride ion and weak acids and bases do not interfere. Using samples containing 12 5 to 250 nig. of boric acid, precision of method is about ±1%. C. A. LUCCHESI and D. D. DeFORD, Northwestern University, Evanston, III. Anal. Chem. 2 9 , 1 1 6 9 ( 1 9 5 7 )
Anal. Chem. 2 9 , 1 153 ( 1 9 5 7 )
Neutron Activation Cross-Section Graphs p-Phenylazophenacyl Esters. Rates of Movement Relative to p-Phenylazophenacyl Bromide on Silicic Acid and Identification by Paper Partition Chromatography
Small amounts of />-phenylazophenacyl derivatives of organic acids are identified by comparing rates of travel on silicic acid columns with />-phenylazophenacyl bro mide. A paper chromatographic method is described. Melting points of 30 additional derivatives are given.
Revised values of all known thermal neutron activation cross sections have been plotted against half-life of radioisotope produced. Standard error of each value is included. Graphs show which elements will be activated with high sensitivity at different irradiation times. W . W . MEINKE and R. A. M A D D O C K , University of Michigan, Ann Arbor, Mich. Anal. Chem. 2 9 , 1 1 7 1 ( 1 9 5 7 )
R. E. KEPNER, A. D. WEBB, R. I. K I N G , and A. D. B O N D , University of California, Davis, Calif. Anal. Chem. 2 9 , 1 1 6 2 ( 1 9 5 7 )
Analysis of Hydrocarbon Blends by Gas-Liquid Partition Chromatography
Determination of Aliphatic Primary A m i n o Nitrogen Compounds by Reaction with 2,4-Pentanedione
Analysis of nine hydrocarbon blends of known com position by gas-liquid partition chromatography gave peak area results which agreed more closely with weight per cent than mole per cent. This agrees well with recent interpretations of peak areas used for quantitative analysis.
2,4-Pentanedione is a weak acid which gives neutral reaction products with primary amines. Primary amine content of aliphatic amines can be determined by adding a measured excess of pentanedione to the sample in pyridine. Excess is titrated with 0.5iV sodium methylate in pyridine. Method is applicable to determination of primary alcoholamines, ethyleneamines, amino acids, aliphatic amines, and ammonia.
L. J. NUNEZ, W . H. ARMSTRONG, and H. W . COGSWELL, Cities Service Research and Development Co., Lake Charles, La.
F. E. CRITCHFIELD and J. B. J O H N S O N , Union Carbide Chemicals Co., South Charleston, W . V a .
Anal. Chem. 2 9 , 1 1 6 4 ( 1 9 5 7 )
Anal. Chem. 2 9 , 1 1 7 4 ( 1 9 5 7 )
VOL. 2 9 , N O . 8 , AUGUST 1 9 5 7
·
9
A
BRIEFS Determination of M o l y b d e n u m in Titanium Alloys by Precipitation from Homogeneous Solution Using Thioacetamide
Molybdenum in titanium alloys can be determined by precipitation of molybdenum sulfide with thioacetamide in much less time than with hydrogen sulfide. The precipitate is dense and easily filtered. W . N . McNERNEY Lexington, Ky.
and
W.
F. W A G N E R ,
University
of
Kentucky,
Anal. Chem. 2 9 , 1 1 7 7 ( 1 9 5 7 )
Analytical Distillation Laboratory Design for Efficiency and Versatility
An analytical distillation laboratory which was designed to make best use of operator's time and to increase pre cision and dependability of resultant data is described. Laboratory contains 18 column stalls. Selected operat ing pressures are maintained automatically. Constant boil-up rates are obtained by semiautomatic control. Control panels allow for rapid selection of reflux ratios and for reading of vapor temperatures. C. B. K I N C A N N O N and MAURICE O . BAKER, Shell Oil Co., Houston, Tex. Anal. Chem. 2 9 , 1 1 8 9 ( 1 9 5 7 )
Constant Current Potentiometric Determination of Manganese
Constant current potentiometry is conveniently applied to detection of end point in the Volhard and LinganeKarplus volumetric methods for manganese with accurate results. Method involves measurement of difference in potential between two platinum wire electrodes polar ized with a constant current. C. O . HUBER and IRVING SHAIN, University of Wisconsin, Madison, Wis. Anal. Chem. 2 9 , 1 1 7 8 ( 1 9 5 7 )
Determination of Tyrosine and Tryptophan in Proteins
A new spectrophotometric determination of tyrosine and tryptophan in proteins is based on two distinct features of the absorption curves between 278 and 293 ναμ. Slope of line tangent to the two characteristic maxima indicates ratio of tyrosine to tryptophan. Extinction at higher maximum measures tyrosine-tryptophan con tent. W . L. BENCZE and KARL SCHMID, Harvard Medical School Massachusetts General Hospital, Boston, Mass.
and
Anal. Chem. 2 9 , 1 1 9 3 ( 1 9 5 7 )
Absorptiometric Method for Determination of Cesium
A convenient, rapid, and accurate procedure is given for indirect determination of cesium in concentrations of 0.133 to 0.931 mg. per ml. Cesium is precipitated with a measured amount of tungstosilicic acid. Excess of reagent is found colorimetrically by reduction with titanium trichloride. Ammonium, potassium, and ru bidium can be tolerated within limited amounts. W . G . KROCHTA with M. G . MELLON, Purdue University, Lafayette, Ind. Anal. Chem. 2 9 , 1 1 8 1 ( 1 9 5 7 )
Determination of Salicylic Acid in Aspirin
Spectrophotometric and visual techniques are described for determination of free salicylic acid in acetylsalicylic acid and aspirin tablets. By correcting for hydrolysis of aspirin under controlled conditions, precision and accuracy within 0.005% are attained. C. W . STRODE, Jr., F. N. STEWART, H. O . SCHOTT, and O . J. COLE M A N , Monsanto Chemical Co., St. Louis, M o .
Rapid Precise Micro Vapor Pressure Method
An easily operated micro vapor pressure measuring de vice uses the evacuable bulb principle with the Harris sample-introduction system. This method is more pre cise and faster than the Reid method and requires a sam ple charge of only 1 ml. Apparatus is so designed that its results correlate with those from the Reid. A. Y. MOTTLAU, Esso Research and Engineering Co., Linden, N. J. Anal. Chem. 2 9 , 1 1 9 6 ( 1 9 5 7 )
Effect of Temperature on the Precision and formance of a Microchemical Balance
Per
A precision of 1.0 γ in rapid routine weighing on a microchemical balance was attained by maintaining balance room at 30° ± 0.2° C. and 30% relative humid ity. Temperature differences caused by operator's presence are minimized and waiting periods are elimi nated. D. E. HULL, California Research Corp., Richmond, Calif.
Anal. Chem. 2 9 , 1 1 8 4 ( 1 9 5 7 )
Colorimetric Determination of Chloride with Mercuric Chloranilate
A colorimetric method for determining chloride in water with a limit of detection of 0.2 p.p.m. is based on reaction of chloride with mercuric chloranilate. Sensitivity is increased by using acid 50% methyl Cellosolve as solvent. Interfering cations are removed with ion exchange resins. J. E. BARNEY II and R. J. BERTOLACINI, Standard Oil Co. (Indiana), Whiting, Ind. Anal. Chem. 2 9 , 11 8 7 (1 9 5 7 )
Anal. Chem. 2 9 , 1 2 0 2 ( 1 9 5 7 )
Separation and Determination of Microgram Quantities of Tellurium in Urine
Microgram amounts of tellurium can be separated from all but a few elements by extraction from a 1ΛΤ acid-0.6JV iodide solution with κ-amyl alcohol-ethyl ether solution. After evaporation of extraction solvent, finely divided tellurium is precipitated by stannous chloride and deter mined photometrically. C. K. H A N S O N , University of Utah, Salt Lake City, Utah Anal. Chem. 2 9 , 1 2 0 4 ( 1 9 5 7 )
V O L . 2 9 , N O . 8 , AUGUST 1 9 5 7
·
11 A
Sensitive Quartz Beam Microbalance
A sensitive quartz beam microbalance is described which operates on the principle of a normal gas density balance. Mass changes can be detected with a precision of 0.05 y and an accuracy of 0.1 y. Balance is very rugged in relation to its sensitivity and is stable over long intervals of time.
Colorimetric A s s a y for Reaction of Sulfhydryl Groups with Organic Mercurials
Sulfhydryl compounds can be determined colorimetrically by reaction with excess />-chloromercuribenzoate. The excess is measured by its bleaching effect on dithizone at 6250 A. Under conditions used 0.03 Mmole of cysteine gave an absorbance change of 0.15 5.
A. W . CZANDERNA and J. M . H O N I G , Purdue University, Lafayette, Ind.
I R W I N FRIDOVICH and PHILIP HANDLER, Duke University School of Medicine, Durham, N. C.
Anal. Chem. 2 9 , 1 2 0 6 ( 1 9 5 7 )
Anal. Chem. 2 9 , 1 2 1 9 ( 1 9 5 7 )
Determination of Low Concentrations of Radioactive Cesium in Water
Radioactive cesium in liter samples of water is separated by adding milligram quantities of cesium chloride carrier, and precipitating as cesium ammonium phosphomolybdate, coprecipitating with potassium sodium cobaltinitrite, or concentrating with ion exchange resins. It is then purified by established radiochemical procedures. Radioactive cesium in river4 water is determined in concentrations between 10 ~ and 10 - 8 microcurie per ml. BERND KAHN, D. K. SMITH, and C. P. STRAUB, O a k Ridge National Laboratory, O a k Ridge, Tenn. Anal. Chem. 2 9 , 1 2 1 0 ( 1 9 5 7 )
Calibration of a n Integrating Motor for Coulometric Titrations
Calibration of an integrating motor has revealed that an empirical relationship which is linear over a range of current levels and resistances exists between motor calibration factor and value of series resistor. Use of this relationship permits calculation of motor factors with an accuracy of 1 to 2 parts per thousand. N. H. FURMAN and A. J. FENTON, Jr., Princeton University, Princeton, N.J. Anal. Chem. 2 9 , 1213 ( 1 9 5 7 )
Separation of Rhodium from Platinum, Palladium, and Iridium by Ion Exchange
Cation-anion differentiation is used to separate rhodium from mixtures with platinum, palladium, and iridium. High-purity rhodium chloride is obtained, but some rhodium usually contaminates separated metals because a small amount of pink anionic form of rhodium chloride is in equilibrium with the yellow cationic form. A 100% cationic form can be prepared. W . M. MacNEVIN and E. S. McKAY, Ohio State University, Columbus 1 0 , Ohio Anal. Chem. 2 9 , 1 2 2 0 (1 9 5 7 )
Determination of Calcium or Zinc Additives in Lubricating Oils and Concentrates. (Ethylenedinitrilo)tetraacetic Acid Titration Method
Calcium or zinc can be determined directly in lubricating oils by mixing sample with acetone, chelating metal with EDTA, and titrating excess EDTA with standard magnesium chloride. An analysis iequires about 20 minutes. P. B. GERHARDT and E. R. HARTMANN, Esso Research and Engineering Co., Linden, N. J. Anal. Chem. 2 9 , 1 2 2 3 ( 1 9 5 7 )
Colorimetric Determination of 1,2-Propanediol and Related Compounds
In a sensitive colorimetric procedure for determination of propylene glycol and its polymers in mixtures of other glycols, propylene glycol is dehydrated with sulfuric acid to a mixture of allyl alcohol and propionaldehyde. Both form a violet-colored complex with ninhydrin in sulfuric acid. As little as one part of propylene glycol can be measured in 1000 parts of ethylene glycol. L. R. JONES and J. A. RIDDICK, Commercial Solvents Corp.,Terre Haute, Ind. Anal. Chem. 2 9 , 1 2 1 4 ( 1 9 5 7 )
Removal of Interferences in the Scott-Sanchis Fluoride Determination
Aluminum, carbonates, organic coloring matter, hydroxides, iron, manganese, phosphates, and sulfates cause errors in the Scott-Sanchis method for fluoride in water. They are removed rather simply by precipitation with cadmium and mercury in presence of sufficient boric acid-sodium hydroxide buffer to maintain a pH of 8.0. R. E. SHOUP, Ohio Department of Health, Columbus 1 0 , Ohio Anal. Chem. 2 9 , 1 2 1 6 ( 1 9 5 7 )
lodometric Estimation of Copper in Presence of Citrate
Presence of complexing compounds interferes with volumetric method for iodometric determination of copper. Addition of small amount of potassium cyanide makes possible titration in normal manner even in presence of ammonium citrate. J. F. SCAIFE, University of Cambridge, England. Anal. Chem. 2 9 , 1 2 2 4 (1 9 5 7 )
Carbon Determination in Biological Material with a Persulfate Oxidation Method
A modified persulfate oxidation method for determining carbon content of biological materials is described. Material is solubilized in concentrated sulfuric acid and an aliquot of this 'added to combustion-diffusion vessel. S. L. CHEN and K. J. H. LAUER, Red Star Yeast & Products Co., Milwaukee, Wis. Anal. Chem. 2 9 , 1 2 2 5 ( 1 9 5 7 )
V O L . 2 9 , N O . 8 , AUGUST 1 9 5 7
·
13
A
BRIEFS Cerimetric Titration of Iron Using a M i x e d Indicator
Diphenylaminesulfonic acid sodium salt is suggested as a warning indicator in cerimetric titration of iron using ferroin indicator. The color change comes just before the abrupt color change of ferroin but does not interfere or affect accuracy of titration. W . R. HEUMANN and Montreal, C a n a d a .
BRANKO BELOVIC, University of
Determination of Hexosamines in Conjunction w i t h Electrophoresis on Starch
Hexosamines in electrophoretic separations on paper must be separated from interfering substances before determination with Ehrlich's reagent. This can be done simply by extraction of compounds formed by hexosamines and acetylacetone with isoamyl alcohol.
Montreal,
Anal. Chem. 2 9 , 1 2 2 6 ( 1 9 5 7 )
O . W . NEUHAUS and MARCIA LETZRING, W a y n e State University College of Medicine, Detroit, Mich.
Determination of Sulfur in Nickel by the Evolution Method
Anal. Chem. 2 9 , 1 2 3 0 ( 1 9 5 7
The evolution method for determination of sulfur in nickel has been improved by using platinic chloride to accelerate solution of nickel in hydrochloric acid. It is shown that all sulfur in nickel is present as sulfide. Modification of the Diacetyl Determination of Urea
C. L. LUKE, Bell Telephone Laboratories, Inc., Murray Hill, N. J.
The photometric method for estimation of urea using diacetyl as color reagent has been modified to give a simple, rapid determination of small quantities of urea in volatile corrosion inhibitor materials. Corrections can be made for interference of sodium nitrite.
Anal. Chem. 2 9 , 1 2 2 7 ( 1 9 5 7 )
Zone Electrophoresis on Sponge Rubber
Foam rubber sponge is a convenient and useful supporting medium for zone electrophoresis of proteins and other substances. Samples are recovered after ionophoresis simply by squeezing the sponges.
R. L. LeMAR and DAVID BOOTZIN, Rock Island Arsenal Laboratory, Rock Island, III. Anal. Chem. 2 9 , 1 2 3 3 ( 1 9 5 7 )
H. K. MITCHELL and L. A. HERZENBERG, California Institute of Technology, Pasadena, Calif. Anal. Chem. 2 9 , 1 2 2 9 ( 1 9 5 7 )
Rinco
Multiple Evaporator
Designed to provide large scale, rapid
rotates at a constant speed of 56 rpm at
evaporation without elevation of tem-
approximately 36 inch-ounces of torque.
peratures; offers rapid evaporation of
Large ( 1 2 " x l 6 " ) cast aluminum H-type
low volatility solvents with capacity of
support base for maximum stability.
2000 ml.
39479 — Multiple Unit, 4 Stage Rinco Evaporator; complete with base and adjustable column, but less glassware and tubing $390.00
From one to four evapora-
tions carried out simultaneously, flasks are quickly
High Capacity Vast Evaporation Multiple Use
and
easily
interchanged.
Driven by a 115 Volt AC motor operatins an enclosed chain-drive mechanism.
Write for Bulletin
19-103
A L O E SCIENTIFIC DIVISION OF A. S. ALOE COMPANY
5655 Kingsbury, St. Louis 12, Mo. LOS ANGELES SEATTLE
·
·
KANSAS CITY
PHOENIX DENVER
·
DALLAS
W A S H I N G T O N , D. PITTSBURGH
C. ·
• • • •
SAN
FRANCISCO
MINNEAPOLIS NEW
ORLEANS
ATLANTA MIAMI
For further information, circle number 15 A on Readers' Service Card, page 73 A
V O L . 2 9 , N O . 8 , AUGUST 1 9 5 7
·
15
For further information, circle number 16 A an Readers' Service Card, page 73 A
A >·
