AC BRIEFS Highlights of the scientific a n d technical articles in this issue
Chronopotentiometric Their Interpretation
Transition
Times
and
Transition time measurements encountered in chronopotentiometric processes are investigated and equations derived. Various mechanisms are distinguished by using certain diagnostic criteria, and reference made regarding the development of analytical problems. W.
H. REINMUTH,
Columbia
University,
N e w York 27, Ν . Υ .
A n a l . C h e m . 33, 322 ( 1 9 6 1 )
Potentiometric Determination of Chlorine Bound to Boron in Mixtures Containing 2-Chlorovinyl Boron Chlorides and Ethyl Boron Chlorides A potentiometric method is devised for determining chlorine bound to boron in organoboron compounds. T h e hydrochloric acid formed through esterification of the chlorine bound to boron is titrated potentiometrically with standard silver nitrate. T h e method indicates good accuracy and reproducibility. H . G . N A D E A U , D. M . O A K S , and R. D. B U X T O N , O l i n Mathieson Chemical Corp., New H a v e n , C o n n . A n a l . C h e m . 33, 341 ( 1 9 6 1 )
Application of Stripping Analysis to the Deter mination of Iodide with Silver Microelectrodes Stripping analyses technique is used for the determination of halides with silver microelectrodes. T h e halide is deposited on the electrode and the silver halide is cathodically stripped by one of two methods. The quantity of electricity involved in the stripping is a function of the quantity of halide deposited. IRVING SHAIN and S. P. PERONE, University of Wisconsin, Madison, Wis. Anal. Chem. 33, 325 (1961)
Voltammetric Determination of Nickel in H a r d Magnetic Alloys
Cobalt
and
The nickel and cobalt contents of hard magnetic alloys are simultaneously determined by a rapid and accurate voltammetric procedure. Sample solutions of standards and of unknowns are prepared containing potassium chloride and pyridine and analyzed according to standard voltammetric procedures. R. D. D E M A R S , I B M Research Center, Yorktown Heights, Ν . Υ . A n a l . C h e m . 33, 342 ( 1 9 6 1 )
Effect of Structure on the Stereochemistry of Electrode Reactions. Monobromo C 4 Dibasic Acids and Esters Polarographic and coulometric reduction data are ob tained for monobromomaleic acid, monobromofuniaric acid, their diethyl esters, and monobromosuccinic acid. In the reduction of monobromofuniaric acid a dimer is formed which represents the first case of dimer produc tion as a result of electrochemical carbon-halogen bond fission. This is proof of a free radical intermediate. P. J . ELVING, The University of Michigan, Ann Arbor, Mich., and ISADORE ROSENTHAL, J . R. HAYES, A . J . MARTIN, The Pennsylvania State University, University Park, Pa. Anal. Chem. 33, 330 (1961)
Investigation of N-Methylacetamide as a Non aqueous Polarographic Solvent The magnitude of the dielectric constant of V-methylacetamide renders it serviceable as a nonaqueous solvent for many polarographically reducible substances, both inor ganic and organic. The suitability of this solvent, along with a mercury pool electrode and tetraethylammonium bromide as a supporting electrolyte, is ascertained in reference to certain procedural variables.
Determination of the Stoichiometry of Uranium Dioxide by Controlled Potential Coulometry A controlled potential coulometric titration procedure is used to determine the oxygen to uranium ratio of uranium oxides. T h e sample is dissolved in hot phosphoric acid in the absence of oxygen and uranium(VI) and total uranium are determined. The results of these titrations are equation factors in the calculation of the uraniumoxygen ratio. R. W . S T R O M A T T and R. E. C O N N A L L Y , General Electric C o . , Richland, W a s h . A n a l . C h e m . 33, 345 ( 1 9 6 1 )
Adsorption on the Liquid Phase in Gas Chromatography A new equation in gas chromatography for retention volumes takes into account the contribution of adsorp tion at the liquid-gas interface. Liquid phase adsorp tion is critical when the liquid is highly polar and the surface area of the support is high. When nonpolar liquid phase is used, adsorption on the support is a factor.
D. E. SELLERS and G . W . L E O N A R D , Jr., Kansas State University, M a n h a t t a n , Kan. A n a l . C h e m . 33, 3 3 4 ( 1 9 6 1 )
R. L. M A R T I N , American O i l C o . , W h i t i n g , I n d .
Null-Point Potentiometric Determination of Fluoride
Gas-Liquid Chromatographic Analysis of Trace Impurities in Styrene Using Capillary Columns
A simple and accurate null-point potentiometric method is used for determining fluoride in various eluates and distillates. The procedure is based on the complexing of fluoride with cesium (IV) and the resultant decrease of the cerium(IV)-cerium(III) redox potential. Anions, chlorides, and nitrates do not interfere. T. A . O ' D O N N E L L and D. F. S T E W A R T , University of M e l b o u r n e , Parkvîlle, N.2., Victoria, Australia A n a l . C h e m . 33, 337 ( 1 9 6 1 )
A n a l . C h e m . 33, 347 ( 1 9 6 1 )
A procedure combining gas-liquid chromatography using capillary columns with a triode argon detector is applied for the separation and detection of trace impurities in styrene. Various xylenes and other impurities are sep arated and detected at concentrations below 25 p.p.m. without the need of a concentration step. O,- L. H O L L I S , The Dow Chemical C o . , Freeport, Tex. A n a l . C h e m . 33, 352 ( 1 9 6 1 )
VOL. 3 3 , N O . 3, MARCH 1 9 6 1
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9 A
BRIEFS Determination of Nitrogen with Gas Chromatog raphy
Automation of Ion Exchange Chromatographic Analysis of Condensed Phosphate Mixtures
Two procedures are developed for nitrogen analyses; one gives a carbon to nitrogen ratio value and the other an absolute nitrogen value. The procedures combine com bustion techniques with gas-liquid chromatography. Pure compounds and components of a mixture are de termined by the procedures.
An interference-free, automatic method combining sev eral techniques is used for the determination of con densed phosphate mixtures in detergents. An ion ex change chromatographic column with a gradient elution system is connected to a Technicon AutoAnalyzer. T h e time required for analysis depends upon the complexity of the phosphate mixture.
R. H. REITSEMA and N. L. ALLPHIN, The Ohio Oil Co., LittleIon, Colo. Anal. Chem. 33, 355 (1961)
D. P. LUNDGREN and N. P. LOEB, Lever Brothers Co., Edgewater, N. J . Anal. Chem. 33, 366 (1961)
Quantitative Analysis for Carbonyl Sulfide in Natural Gas by Gas-Liquid Chromatography
Standardization of Silicic Acid for Chromatog raphy
A gas-liquid method using iV,iV-di-»-butylacetamide as a stationary phase determines from 25 to 1000 p.p.m. car bonyl sulfide in natural gas. Sensitivity is obtained by using a thermistor-type thermal conductivity detector cell. One analysis is completed within six minutes.
Three methods are devised for the activation and stand ardization of silicic acid to the equivalent activities of aluminum oxide designated by the Brockmann scale. Data for each activity are obtained by the positions and movement of certain dyes.
J . A. SCHOLS, Dow Chemical of Canada, Ltd., Sarnia, Ontario
ROGER HERNANDEZ, RAYMOND HERNANDEZ, Jr., St. Mary's University, and L. R. AXELROD, Southwest Foundation for Research and Education, San Antonio, Tex. Anal. Chem. 33, 370 (1961)
Anal. Chem. 33, 359 (1961)
Primary Amyl Alcohols Chromatography
Determined
by
Gas
A rapid and reproducible gas chromatographic procedure uses Tide as the column packing for determining primary amyl alcohols in mixtures. The weight percentage com position is calculated using the rectangular method of geometric approximation which utilizes retention time peak height. P. J . PORCARO and V. D. JOHNSTON, The Givaudan Corp., Delawanna, N. J . Anal. Chem. 33, 361 (1961)
The Rapid Preparation of Fatty Acid Esters for Gas Chromatographic Analysis A rapid and acids to their in an excess converted to tion reaction
simple procedure is used to convert fatty respective methyl esters. F a t t y acids boiled of boron trifluoride—methanol reagent are methyl esters in 2 minutes. The esterifieais essentially complete.
L. D. METCALFE and A. A . SCHMITZ, Armour Industrial Chem ical Co., McCook, III. Anal. Chem. 33, 363 (1961)
Quantitative Determination of Sugars by Rapid Horizontal Paper Chromatography
The Rapid, Trace Analysis of Phosphate Mixtures by a Paper Chromatographic, Densitometric Procedure As little as 0.02% Να.ιΡ20τ in soluble orthophosphates is determined. Results are given on extension of the tech nique to soluble condensed phosphate mixtures and cal cium phosphates. R. H. KOLLOFF, Monsanto Chemical Co., St. Louis 66, Mo. Anal. Chem. 33, 373 (1961)
The Mass Spectrometric Analysis of Asphalt. Preliminary Investigation
A
Mass spectrometric technique is applied to the analysis of asphalt and other residual petroleum fractions. Modi fication of a high temperature mass spectrometer permits the placement of asphalt samples within the ionization region. Individual mass peaks are not resolved, but in formation is provided concerning the molecular structure of asphalts. R. J. CLERC and M. J . O'NEAL, Jr., Shell Oil Co., Houston I, Tex. Anal. Chem. 33, 380 (1961)
Flame Spectrophotometric Study of Silver
High temperature, horizontal paper chromatography is used for the separation and determination of sugars in a mixture. Two hour separation time is obtained with an ethyl ketone-propionic acid-water solvent system. The colored sugar spots are measured on a densitometer.
A thorough investigation is made of the flame emission characteristics of silver in oxygen-hydrogen, and oxygenactcylene flames, and in flames into which organic solvents are aspirated. Interferences of metals at the two ultra violet emission lines of silver at 328.0 and 338.3 are noted.
J. B. HIMES, L. D. METCALFE, and HELMA RALSTON, Armour Industrial Chemical Co., McCoolc, III. Anal. Chem. 33, 364 (1961)
J. A. DEAN and C. B. STUBBLEFIELD, University of Tennessee, Knoxville, Term. Anal. Chem. 33, 382 (1961) VOL. 33, NO. 3, MARCH 1961
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BRIEFS Correlation of Mass Spectra with Structure in Aromatic Oxygenated Compounds. Methyl Sub stituted Aromatic Acids and Aldehydes Mass spectra data are correlated with chemical structure for a series of aromatic acids and aldehydes. This study confirms that the respective positions of the various substituents on the benzene ring have a leading importance in the formation of fragment ions. 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.
Spectrochemical Determination Biological Materials
of
Yttrium
in
Ion exchange enrichment technique is combined with spectrochemical analysis for determining yttrium in bone ash and egg shells. The procedure offers extreme versa tility in handling samples of different sizes and yttrium concentration. Elements of the rare earth group may be determined by this procedure. C . L. G R A N T , Rutgers—The State University, New Brunswick, N . J . A n a l . C h e m . 33, 401 ( 1 9 6 1 )
A n a l . C h e m . 33, 386 ( 1 9 6 1 )
Total Analysis of Olefinic Naphthas by Spectrometry
Mass
A new mass spectra method is developed that combines low and normal voltage spectra so that the strong features of each offset the weak feature of the other. T h e new procedure is applied t o the determination of hydrocarbon types in olefinic naphthas. The mass spectrometer is modified to provide the low ionizing and fixed repeller voltages required. A . J . F R I S Q U E , H . M . G R U B B , C . H . E H R H A R D T , and R. W . V A N D E R H A A R , Standard O i l C o . ( I n d i a n a ) , W h i t i n g , I n d .
Spectrophotometric Determination tium with Toluene-3,4-dithiol
of Techne
Microgram quantities of technetium are determined by spectrophotometric procedure. Technetium is reacted with toluene-3,4-dithiol in acid medium and the com plex extracted with carbon tetrachloride. The color in tensity is measured at 450 τημ. Separation of technetium is required as many elements interfere. F. J . M I L L E R and P. F. T H O M A S O N , O a k Ridge National Lab oratory, O a k Ridge, Tenn. A n a l . C h e m . 33, 4 0 4 ( 1 9 6 1 )
A n a l . C h e m . 33, 389 ( 1 9 6 1 )
Characterization of Hydroxyl Compounds. Identification of Their 3,5-Dinitrobenzoate Esters by X-Ray Diffraction An x-ray diffraction technique is devised for the identifi cation of hydroxyl compounds. Reference patterns are obtained for a series of 3,5-dinitrobenzoate esters of alco hols. For qualitative and semiquantitative analyses of alcoholic mixtures this technique may be used in com bination with infrared spectrometric techniques. K. J . G A R S K A , R. C . D O U T H I T , and V . A . Y A R B O R O U G H , Union C a r b i d e Chemicals C o . , South Charleston, W . V a .
Determination of Dissolved Radium A radiochemical procedure is developed for determining dissolved radium in public water supplies. Radium is coprecipitated with barium and lead sulfates using sul furic acid. T h e carrier and radium are dissolved in nitric acid and reprecipitated with E D T A . The barium sulfate precipitate is washed and transferred to a planchet for counting. A . S. G O L D I N , Robert A . Taft Sanitary Engineering Center, C i n cinnati, Ohio A n a l . C h e m . 33, 4 0 6 ( 1 9 6 1 )
A n a l . C h e m . 33, 392 ( 1 9 6 1 )
Flame Photometric Determination of Phosphorus in the Presence of Sodium, Potassium, and Other Cations Rapid photometric procedure accurately determines the phosphorus content of sodium and potassium ortho- and polyphosphates. T h e method is based on the strong inter ference of phosphorus on the flame emission of strontium at 660 π\μ. For samples of low oxidation state of phos phorus, a calibration curve is required. D. N . B E R N H A R T , W . B. C H E S S , and D A V I D R O Y , Victor C h e m i cal Works, C h i c a g o Heights, I I I .
Determination of Tritium in W a t e r and Urine. Liquid Scintillation Counting and Rate-of-Drift Determination Liquid scintillation counting and rate-of-drift determina tion are two techniques employed for the determination of tritium in water and urine. The lower limit of detec tion for both procedures is about 0.005 με. per liter. The rate-of-drift technique is less expensive and analyzed 4 to 6 samples per day. F. E. BUTLER, E. I. du Pont d e Nemours and C o . , Inc., Aiken, S. C . A n a l . C h e m . 33, 4 0 9 ( 1 9 6 1 )
A n a l . C h e m . 33, 3 9 5 ( 1 9 6 1 )
X-Ray Spectrometric Determination of Stontium in Human Serum and Bone An x-ray spectrometric procedure is used to determine the strontium content of human scrum and bone. Special evaporating technique provides a uniform spot on filter paper for the strontium analysis. T h e calcium-strontium ratios of certain bones are obtained and original values given for human blood serum. S A M U E L N A T E L S O N and BERTRUM S H E I D , Roosevelt Hospital, N e w York, Ν . Υ. A n a l . C h e m . 3 3 , 396 ( 1 9 6 1 )
Radiotracer Method for Determination of Ad sorption of Surfactants on Copper Phthalocyanine The adsorption of surfactants on copper phthalocyanine is determined by radiochemical procedures using carbon-14 compounds. Adsorption values are obtained for undried samples and dried samples, and the surface area cal culated from the difference. Sodium stéarate and acetyltrimethylammonium bromide are the surfactants studied. W I L L I A M S E A M A N and G . L. ROBERTS, American C o . , Bound Brook, N . J .
Cyanamid
A n a l . C h e m . 33, 4 1 4 ( 1 9 6 1 )
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BRIEFS Spectrophotometric Determination of Traces of Calcium in Sodium. Visible and Ultraviolet Methods Using Sodium Naphthalhydroxamate
Spectrophotometric Determination of Phosphate in the Presence of Highly Labile Phosphorus Compounds
Trace amounts of calcium in reactor grade sodium are determined by a sensitive spectrophotometric procedure. Calcium is precipitated with sodium naphthalhydroxamate and the precipitate dissolved in O.IM E D T A solution. The color intensity of the liberated naphthalhydroxamate ion is measured at 339 m,u.
A more sensitive spectrophotometric method for deter mining phosphate is obtained by dissolving the reagent, ammonium molybdate, in iV,./V-dimethylformamide and measuring the color intensity at 335 ιημ. High protein concentrations in the test solution diminish the color yield.
D. K. BANERJEE, C. C. BUDKE, and F. D. MILLER, U. S. In dustrial Chemicals Co., Cincinnati 37, Ohio
L. C. MOKRASCH, University of Kansas Medical Center, Kansas City 12, Kan. Anal. Chem. 33, 432 (1961)
Anal. Chem. 33, 418 (1961)
Application of Pyrocatechol Violet as a Colorimetric Reagent for Tin The reaction between quadrivalent tin and Pyrocatechol Violet indicates a sensitive reagent for the colorimetric determination of tin. Bivalent tin does not react with this reagent. Zirconium, titanium, bismuth, antimony, gallium, and molybdenum interfere. W . J . ROSS and J . C. WHITE, Oak Ridge National Laboratory, Oak Ridge, Tenn. Anal. Chem. 33, 421 (1961)
Extraction of Tin with Tris(2-ethylhexyl)phosphine Oxide and Its Determination in Non aqueous Medium with Pyrocatechol Violet A sensitive spectrophotometric method is used for de termining tin alloys. Tin is extracted from solution with a cyclohexane solution of tris(2-ethylhexyl)phosphine oxide and complexed with Pyrocatechol Violet. Maxi mum absorbance is measured at 575 ταμ. Backwashing re moves gallium, antimony, iron, and molybdenum. W . J . ROSS and J . C. WHITE, Oak Ridge National Laboratory, Oak Ridge, Tenn. Anal. Chem. 33, 424 (1961)
Spectrophotometric Determination of Dibutyltin Dichloride Small amounts of dibutyltin dichloride in the presence of mono-, tri-, and tetrabutyltin are determined by spectro photometric procedures. In an acid medium, dibutyltin reacts with diphenylcarbazone forming a complex with an absorption maximum at 530 mfi. T h e interference of tributyltin is overcome by extraction with E D T A .
Determination of Phosphorus in Biological M a t e rial Trace amounts of phosphorus in biological materials are determined spectrophotometrically. Phosphorus is evolved from acid solution in a nonoxidizing atmosphere and is collected on mercuric bromide. I t is eluted as phosphoric acid and determined colorimetrically as molybdenum blue at 720 ταμ. W . T. OLIVER and H. S. FUNNELL, Ontario Veterinary College, Guelph, Canada Anal. Chem. 33, 434 (1961)
Spectrophotometric Determination of Vanadium (V) with N-Benzoyl-N-phenylhydroxylamine A highly specific spectrophotometric method is devised for determining vanadium(V) using A'-benzoyl-V-phenylhydroxylamine as the reagent. The complex is developed in acidic solution and extracted with chloroform. The absorbance of the violet color is measured at, 510 ταμ. I n terfering substances are easily removed by standard pro cedures. USHA PRIYADARSHINI and S. G. TANDON, Jabalpur University, Jabalpur, India Anal. Chem. 33, 435 (1961)
Spectrophotometric Titration of W e a k Acids or Bases in Aqueous Solution Using the Type II Plot Spectrophotometric titration of weak acids and bases is conducted in aqueous solution using Type I I plot. T h e accuracy of results is dependent upon the constancy of the ionic strength during titration. Type I I titration is no lengthier than conventional photometric titration when absorbance measurements are made at one wave length, and only slightly longer when two wave lengths are in volved.
R. T. SKEEL and C. E. BRICKER, Princeton University, Princeton, N. J . Anal. Chem. 33, 428 (1961)
STANLEY BRUCKENSTEIN and D. C. NELSON, University of Minnesota, Minneapolis 14, Minn. Anal. Chem. 33, 438 (1961)
N e w Spectrophotometric denum
Spectrophotometric Determination Amounts of Silver by Dithiol
Method
for
Molyb
of
Trace
A rapid and sensitive spectrophotometric method is used for determining molybdenum in low-alloy steels. Molyb denum is separated by ion exchange and complexed with phenylfiuorone. Maximum absorbance of the red-orange complex is measured at 550 ταμ. Concentration limits for molybdenum are 0.1 to 0.5% in low-alloy steels.
A simple and direct spectrophotometric method deter mines microquantities of silver. Silver is reacted with toluene-3,4-dithiol and the resultant silver-dithiol is dis persed in sulfuric acid. T h e absorbance of the dispersion is measured at 416 ταμ. Lead, mercury, tin, and arsenic interfere.
A . H. BLACK and J . D. BONFIGLIO, University of Toledo, Toledo 6, Ohio
J. P. DUX and W . R. FEAIRHELLER, American Viscose Corp., Marcus Hook, Pa. Anal. Chem. 33, 445 (1961)
Anal. Chem. 33, 431 (1961) Circle No. 111 on Readers' Service Card
VOL. 33, NO. 3, MARCH 1961
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15 A
BRIEFS Ebulliometric Apparatus for Studying NumberAverage Molecular Weights of Polymers
Cation Exchange Elution of Metallic Chlorides by Hydrochloric Acid
A Menzies-Wright type of ebulliometer and an 80-j unction thermopile are combined with a stable recording electri cal system for measurements from which a polymer m o lecular weight is calculated. Temperature sensitivity is of the order of 0.015 millidegrce. An analysis may be com pleted within four hours.
Resin cross linking and eluent concentration are variables in a study of the ion exchange separation of manganese (II), i r o n ( I I I ) , nickel(II), copper(II), zinc(II), cadmium ( I I ) , and mercury(II). The data obtained give a relative indication of the effects of these variables on the position of the equilibrium and on the rate of exchange.
C. A . GLOVER and R. R. STANLEY, Tennessee Eastman Co., Kingsport, Tenn. Anal. Chem. 33, 447 (1961)
C . K. M A N N and C . L. S W A N S O N , Florida State University, Tallahassee, Fla. A n a l . C h a m . 33, 459 (1961 )
Spectrophotometric Determination of Micro gram Quantities of Vaporizable W a t e r from Solids Using Karl Fischer Reagent A spectrophotometric method is developed using Karl Fischer reagent for determining the water content of solids. The water is vaporized into a dry nitrogen stream, condensed, and transferred to the reagent. The absorbance is measured at 475 ταμ. Then sensitivity is 0.5 micro grams of water. D. A. OTTERSON, National Aeronautics and Space Administra tion, Cleveland, Ohio Anal. Chem. 33, 450 (1961)
Determination of Methyl Groups in Alkylbenzenes by Chromic Acid Oxidation The Kuhn-Roth method for determining C-methyl groups in alkylbenzenes is modified. T h e sample is oxidized in a sealed tube with 5AT chromic acid—sulfuric acid mixture at 130° C. The procedure is applied to monoalkylbenzenes, polyalkylbenzenes, and monoaromatic petroleum fractions. Benzoic acid does not interfere. S. Θ. BRANDENBERGER, L. W . MAAS, and ISAAC DVORETZKY, Shell Oil Co., P.O. Box 100, Deer Park, Tex.
Measuring Melting Points and Rates of Crystalli zation of Polymers by Recording Changes in Birefringence A rapid instrumental procedure is devised for determining melting points and rate of crystallization of polymer powders, films, or molded pieces. The apparatus auto matically and simultaneously measures and records the brightness between crossed niçois and the temperature. The specimen must be nearly or completely transparent. C. W . HOCK and J . F. ARBOGAST, Hercules Powder Co., W i l mington, Del. Anal. Chem. 33, 462 (1961)
Determination of the Distribution of Nonionic Surface Active Agents between W a t e r and Isooctane A procedure is outlined for determining the distribution coefficient of nonionic surface active agents. The surface active agent, »-ieri,ieri-oct3'lphenoxypoly(8.7) oxyethylene-ethyl alcohol (OPE„.-) is used for distribution coefficient between water and a paraffin, surface tension, and interfacial tension measurements.
Anal. Chem. 33, 453 (1961)
H. L. GREENWALD, E. B. KICE, M. KENLY, and JOSEPH KELLY, Rohm & Haas Co., Philadelphia, Pa. Anal. Chem. 33,465 (1961)
High Temperature Infrared Cells for Studies of Solid High Polymer Reactions
Oxidimetric Determination of n-Butyllithium in Hydrocarbons Using Vanadium Pentoxide
Solid polymer reactions at high temperatures are studied using thermostatically controlled infrared cells. D a t a are obtained on the kinetics and mechanism of oxidation of polymers and the effects of vulcanization on polymer microstructure. T h e thermostatically controlled cells ex pand the application of infrared spectrophotometry.
A simple oxidimetric method is described for determining n-butyllithium in hydrocarbons. The sample is reacted with vanadium pentoxide and the reduced vanadium is titrated with sulfatoceric acid. Concentration of n-butyllithium is calculated from the titration value.
W . A . BISHOP, Copolymer Rubber and Chemical Corp., Baton Rouge, La, Anal. Chem. 33, 456 (1961)
P. F. COLLINS, C. W . KAMIENSKI, D. L. ESMAY, and R. B. ELLESTAD, Lithium Corp. of America, Inc., Bessemer City, N. C. Anal. Chem. 33, 468 (1961)
VOL. 33, NO. 3, MARCH 1961
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