AC BRIEFS Highlights of the scientific and technical articles in this issue
Determination of Trace Quantities of Hydrocarbons in the Atmosphere
Chromatography of A m i n o Acids on Sulfonated Polystyrene Resins. A n Improved System
An accurate method for determination of hydrocarbons in the atmosphere employs a freeze-out extraction technique and mass spectrometer for quantitative identification. Water vapor, carbon dioxide, and residual air interference is eliminated by absorption on Ascarite-Dehydrite column. Sensitivity is in the order of 1.0 p.p.m.
The use of finely pulverized (8%) Amberlite IR-120 im proves the chromatographic separation of amino acids. The neutral and acidic amino acids are separated on a 150-cm. column and eluted with two buffers. A 15-cm. column and one buffer are used for the basic amino acids separation. Flow rates can be up to 30 ml. per hour.
E. R. Q U I R A M and W . F. BILLER, Esso Research and Engineering Co., Linden, N. J.
STANFORD M O O R E , D. H. SPACKMAN, and W . H. STEIN, Rockefeller Institute for Medical Research, New York 2 1 , Ν. Υ.
Anal. Chem. 3 0 , 1 1 6 6 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 1 8 5 ( 1 9 5 8 )
Evaluation of Air-Borne Particulates in Atmospheric Pollution Studies
A study is made to determine a more exact relation be tween absorbance of stains on filter paper and the carbon content of air-borne particulates in the atmosphere under various meteorological conditions. A technique for measuring hourly variations is devised. The data, sta tistically analyzed, satisfy the equation, W — aDb; a and b are constants which are influenced by meteorological conditions. MORRIS KATZ, Department of National Health and W e l f a r e , O t t a w a , C a n a d a , and H. P. SANDERSON and M . B. FERGUSON, Technical Advisory Board on Air Pollution, Windsor, Ontario, C a n a d a
Automatic Recording Apparatus for Chromatography of A m i n o Acids
Simpler and more rapid quantitative determination of amino acids is based on an instrument which records the ninhydrin color value of effluent from ion exchange col umns. Eluted material, mixed with ninhydrin reagent, is heated, and absorbance measured continuously at 570 and 440 ηΐμ. Precision is ± 3 % for loads ranging from 0.1 to 3.0 Mmoles of each amino acid. Protein or peptide hydrolyzates are analyzed in 24 hours; and blood plasma, urine, etc., in 48 hours. D. H. SPACKMAN, W . H. STEIN, and STANFORD M O O R E , Rockefeller Institute for Medical Research, New York 2 1 , Ν. Υ.
Anal. Chem. 3 0 , 1 1 7 2 ( 1 9 5 8 )
Determination of Low Concentrations of Hafnium in Reactor-Grade Zirconium Metal and Zirconium Alloys by Neutron Activation Analysis
Thermal neutron activation of hafnium produces four radionuclides which serve as a basis for two analytical procedures for the determination of hafnium in zirconium metals and alloys. The rapid method uses hafnium-179 (half life of 19 seconds) and the second method uses hafnium-181 or hafnium-175 (half life 46 and 70 days, respectively). Methods sensitivity is in the order of 10 p.p.m. W . D. MACKINTOSH and R. E. JERVIS, Atomic Energy of C a n a d a , Chalk River, Ontario, C a n a d a
Anal. Chem. 3 0 , 1 1 9 0 ( 1 9 5 8 )
Separation of Isomeric Polyphenyls by Adsorption Chromatography
Chromatographic separation of polyphenyls by several procedures is compared. General indications are that alumina-iso-octane provides the best system, that struc ture and molecular weight of polyphenyls are critical, and that separation of isomeric polyphenyls follows a pattern which is correlated with the stereo configurations of the molecules. MAX HELLMAN, R. L. ALEXANDER, Jr., and C. F. COYLE, National Bureau of Standards, Washington 2 5 , D. C. Anal. Chem. 3 0 , 1 2 0 6 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 1 8 0 ( 1 9 5 8 )
Ion Exchange-Spectrophotometric Determination of Thorium
Material Deposited along Path of Chromatographed Sugar Spot
Thorium is selectively separated from interfering ele ments by one of two ion exchange procedures prior to analysis with thorin reagent. An anion column (Dowex1) removes chloro complexes of interfering materials; thorium is not absorbed. For sulfuric acid leach liquors a cation column (Amberlite IR-120) absorbs thorium, which is selectively eluted with 3Λί sulfuric acid.
A radioassay method is used to detect small amounts of material along the path of sugar during paper chroma tography. Absorption on and interaction with cellulose fibers accounts for the presence of trace amounts of orig inal sugar in the path. Lost material, not the starting sugar, may be impurities not removed during purification of the sugar or those obtained during chromatographic procedure.
O . A. NIETZEL, B. W . WESSLING, and M. A. DeSESA, National Lead Co., Inc., Winchester, Mass.
C. K. HORDIS and G . N . K O W K A B A N Y , The Catholic University of America, Washington, D. C.
Anal. Chem. 3 0 , 1 1 8 2 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 2 1 0 ( 1 9 5 8 )
VOL.
30, N O . 7, JULY 1 9 5 8
·
9
A
BRIEFS Separation of Halogenated Acetic and Acids by Paper Chromatography
Propionic
Carbon-Type Composition of Viscous Fractions of Petroleum. Density-Refractivity Intercept Method
An improved procedure for the paper chromatographic separation of halogenated aliphatic acids is described. Acetic acid and various chloro and bromo isomers are studied along with certain halogenated propionic acids. Developing system is butanol-ammonia; R/ values are recorded.
The carbon-type composition of polycyclic compounds in lubricating oils can be determined from densities and refractivity intercept values. The latter are derived from equations based on molecular weight and viscositygravity constant. All types of viscous petroleum oils, having hydrocarbons of 15 to 40 carbon atoms, can be analyzed with a high degree of accuracy.
J. W . CHITTUM, T. A. GUSTIN, R. L. McGUlRE, and J. T. SWEENEY, The College of Wooster, Wooster, Ohio Anal. Chem. 3 0 , 1 2 1 3 ( 1 9 5 8 )
S. S. KURTZ, Jr., R. W . K I N G , W . J. STOUT, and M. E. PETERKIN, Sun Oil Co., Marcus Hook, Pa. Anal. Chem. 3 0 , 1 2 2 4 ( 1 9 5 8 )
Compact Countercurrent Distribution Apparatus
The construction and operation of a compact, flexible, and easily adjustable countercurrent distribution appara tus are described. Specially designed tubes reduce cocurrent flow. Automatic drives and electric switches eliminate mechanical operation. SAMUEL R A Y M O N D , Columbia University, N e w York, Ν. Υ. Anal. Chem. 3 0 , 1 2 1 4 ( 1 9 5 8 )
Portable, Automatic A l a r m for Detection of Toxic Agents in Atmosphere
A portable electronic alarm system is developed to deter mine trace amounts of nerve gas in the atmosphere. The mechanism depends on the amount of total reflected light reduction caused by the colored compound formed when the gas reacts with dianisidine and sodium pyro phosphate peroxide. Nitrogen dioxide, chlorine, and chlorosulfonic acid screening smoke, give false alarms. J. C. Y O U N G , Army Chemical Center, M d . , and J. R. PARSONS and H. E. REEBER, Radio Corp. of America, Camden, N. J. Anal. Chem. 3 0 , 1 2 3 6 ( 1 9 5 8 )
Chromatographic Analysis of Gas Mixtures Containing Nitrogen, Nitrous O x i d e , Nitric O x i d e , Carbon M o n o x i d e , and Carbon Dioxide
Nitrogen, nitrous oxide, nitric oxide, carbon monoxide, and carbon dioxide are separated in a two-phase column of silica gel separated by iodine pentoxide, and analyzed by gas chromatography. The column at elevated temper ature oxidizes carbon monoxide to carbon dioxide and nitric oxide to nitrogen dioxide. Gaseous mixtures can be analyzed in 10 minutes. R. N. SMITH, JAMES SWINEHART, and D. G. LESNINI, Pomona College, Claremont, Calif. Anal. Chem. 3 0 , 1 2 1 7 ( 1 9 5 8 )
Alarms and Analyzers for Nerve Gas Vapors
The chemical system and instrumental design for an automatic detector for nerve gas are described. Indole in a buffer solution is the sensitive, stable reagent, react ing to form the fluorescing indoxyl. The instrument acts as an alarm device or analyzer for GB, isopropyl esters of methane phosphonyl fluoride, GA, and the ethyl esters of dimethylamido-cyanophosphoric acid. R. H. CHERRY, G. M. FOLEY, C. O . BADGETT, and R. D. EANES, Leeds & Northrup Co., Philadelphia, Pa., and H. R. SMITH, Army Chemical Center, M d . Anal. Chem. 3 0 , 1 2 3 9 i l 9 5 8 )
Standardization of Mass Spectra by Means of Total Ion Intensity
The prpblem of sample volume and instrumental sensi tivity in mass spectra analysis of petroleum oils and re lated compounds is overcome by using a total ion in tensity method—i.e., the summated peak heights of a mass spectrum. The method has been applied to the corre lation of mass spectra with molecular structure and to the analysis of lubricating oil saturate fractions. ARCHIE H O O D , Shell Oil Co., Houston, Tex. Anal. Chem. 3 0 , 1 2 1 8 ( 1 9 5 8 )
Titration of Weak Bases in Strong Salt Solutions
Titration- 9of weak bases (ionization constants of less than 1 Χ 10 ) by potentiometric methods or by use of in dicators is made feasible by use of strong aqueous solu tions of neutral salts (6 to 8Λί). These salts enhance the potentiometric break in acidimétrie titrations. Method is applicable to salts of some weak acids and strong bases and to individual amino nitrogen of polyfunctional amines but not to amino acids. F. E. CRITCHFIELD and J. B. J O H N S O N , Union Carbide Co., South Charleston, W . V a .
Chemicals
Anal. Chem. 3 0 , 1 2 4 7 ( 1 9 5 8 )
Aromatic Types in Heavily Cracked Gas Oil Fraction. Combined Use of Ultraviolet and Mass Spectrometry
The combined use of ultraviolet spectrophotometry and mass spectrometry at low voltage ionization levels pro vides a more detailed analysis of chromatographic frac tions of heavy gas oil materials. Trace amounts of trinuclear and tetranuclear aromatic compounds are de tected. The technique eliminates spurious peaks ob tained with high voltage conventional mass spectra.
Determination of Water Vapor in Nitrogen. Thermal Conductivity Measurement of Hydrogen Liberated from Calcium Hydride
The water vapor in nitrogen is determined by reacting with calcium hydride at 2 3 5° C. and measuring the liberated hydrogen by thermal conductivity. Effective range is between 200 and 2000 p.p.m. Alcohol vapors interfere, but in the absence of water vapor the method is applicable to determine alcohol vapors.
R. J. G O R D O N , R. J. M O O R E , and C. E. MULLER, Shell Oil Co., Martinez, Calif., and Shell Development Co., Emeryville, Calif.
H. W . LINDE and L. B. ROGERS, Massachusetts Institute of Technology, Cambridge 3 9 , Mass.
Anal. Chem. 3 0 , 1 2 2 1 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 2 5 0 ( 1 9 5 8 )
VOL. 30, N O .
7,
JULY
1958
·
11
A
Polarographic Determination of Hydrogen Peroxide, Formaldehyde, and Acetaldehyde in Mixtures
Polarography of Metal Ions in Fused Lithium Chloride-Potassium Chloride Eutectic
Hydrogen peroxide, formaldehyde, and acetaldehyde in aqueous solutions are determined by a three-stage polarographic procedure. Peroxides respond in an acid medium, aldehydes in an alkaline medium; dimedon (5,5-dimethyl-l,3-cyclohexanedione) is used to block formaldehyde interference during acetaldehyde determination. Individual concentrations do not affect procedure.
The polarographic characteristics of certain metal ions in fused lithium chloride—potassium chloride at 450° are studied and the feasibility of employing this technique as an analytical tool is investigated. Voltammetric measurements, using a platinum reference electrode and a platinum, tungsten, or carbon microelectrode, were made for copper, zinc, cadmium, thallium, tin, chromium, mercury, bismuth, and other metal ions.
SAMUEL SANDLER a n d Y U - H O C H U N G , University o f Toronto, Toronto, Ontario, Canada
H. A. LAITINEN, C. H. LIU, and W . S. FERGUSON, University of Illinois, Urbana, III.
A n a l . Chem. 3 0 , 1 2 5 2 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 2 6 6 ( 1 9 5 8 )
Polarographic Estimation of Thiophenes and Aromatic Sulfides in Petroleum
Polarography of Thiourea
The determination of thiourea by polarographic technique is studied with respect to the formation constants for the complexes between mercury and thiourea in neutral and acid solutions. These constants were found to be iC2 = 1.5 X 1022; K , = 5 X 1024; K4 = 6.3 X 1026. C. J. N Y M A N a n d E. P. PARRY, State College o f W a s h i n g t o n , Pullman, Wash. A n a l . Chem. 3 0 , 1 2 5 5 ( 1 9 5 8 )
A polarographic procedure for the determination of condensed thiophenes and aromatic sulfides in crude petroleum oils is described. The sulfur compounds are oxidized to sulfones by hydrogen peroxide and reduced at the dropping mercury electrode. Good agreement between the total sulfur and the sum of the percentages of sulfur compounds determined attest to the accuracy of the method. H. V. DRUSHEL a n d J. F. MILLER, Mellon Institute o f Industrial Research, Pittsburgh, Pa. Anal. Chem. 3 0 , 1271 ( 1 9 5 8 )
Dialysis as a n Analytical Tool
Dialysis is serviceable as an analytical tool for detecting differences in molecular size and a test for heterogeneity. The method is based on the rate coefficient of dialysis for substances in a standardized solution. It can characterize unknown substances in mixtures, and by using known mixtures can characterize membranes. HANS H O C H a n d Richmond, V a .
Spectroscopic Detection of Silicon in Organic Silicon Compounds
Virginia,
A qualitative and semiquantitative method for determining silicon in organosilicon compounds is described. Sample is decomposed in acid solution by a spark discharge between platinum electrodes. Silicon is detected by spectroscopic analysis, emission lines at 6347 and 6371 A. units.
A n a l . Chem. 3 0 , 1 2 5 8 ( 1 9 5 8 )
JACK RADELL, P. D. HUNT, E. C. MURRAY, a n d W . D. BURROWS, Wright-Patterson Air Force Base, O h i o .
R. C. WILLIAMS, M e d i c a l
College o f
A n a l . Chem. 3 0 , 1 2 8 0 ( 1 9 5 8 )
Permselective Applications
Membrane
Electrodes.
Analytical
The molding of certain ion exchange resins with plastic binder produces cation- and anion-selective membranes. Selectivity within ionic species is poor but indicates promising developments. The sodium form of a sulfonated polystyrene membrane is used as a pNa electrode. Other membranes are used as indicator electrodes in potentiometric titration procedure. J. S. PARSONS, American C y a n a m i d Co., Bound Brook, N. J. A n a l . Chem. 3 0 , 1 2 6 2 ( 1 9 5 8 )
Colorimetric Determination of Molybdenum in the Presence of Tungsten. Modified Mercaptoacetate Method
The mercaptoacetic acid method for molybdenum is made more specific by using citric acid to eliminate interference from tungsten. Possible interference by moderate amounts of niobium, tantalum, zirconium, and titanium is also eliminated. Method is applicable to analyses of high temperature alloys. D. A. OTTERSON a n d J. W . GRAAB, N a t i o n a l Advisory Committee for Aeronautics, C l e v e l a n d , O h i o A n a l . Chem. 3 0 , 1 2 8 2 ( 1 9 5 8 )
VOL. 3 0 , NO. 7 , JULY
1958
·
13
A
BRIEFS Spectrophotometry A s s a y Using N-Ethylmaleimide
Anomalous Copper Results w i t h the Use of Porcelain Crucibles
Erratic results in the determination of copper in tuna fish meat were traced to the porcelain crucible used in dryashing the sample. The meat acts as a flux, drawing out the copper from the porcelain material. The condition is corrected by using platinum or silica crucibles or a wetash technique with nitric-perchloric acid mixture. HARRY ZEITLIN, M. M. FRODYMA, and GEORGE IKEDA, University of Hawaii, Honolulu 1 4 , Hawaii
for
Sulfhydryl
Groups
A rapid, simple spectrophotometry method specific for sulfhydryl groups is developed using ]V-ethylmaleimide (NEM) at neutral pH. The decrease in light ab sorption of NEM at 300 ηΐμ is equal to the per cent sulf hydryl group present. No standard thiol solution is re quired, but method is limited to total sulfhydryl in pro teins. Ν. Μ. ALEXANDER, Veterans Administration Hospital, West Conn., and Yale University, N e w Haven, Conn.
Haven,
Anal. Chem. 3 0 , 1 2 8 4 ( 1 9 5 8 ) Anal. Chem. 3 0 , 1 2 9 2 ( 1 9 5 8 )
Automatic Titrator Based on Constant Current Potentiometric Titrations
An automatic titrator is described for use with constant current potentiometric titrations. Termination of titrant flow is based on the shape of the titration curve. Titra tions of ferrous, manganous, thiosulfate, and chloride ions were made; compared to manual titration values, the precision and accuracy are extremely fine. IRVING SHAIN and C. O . HUBER, University of Wisconsin, Madison, Wis. Anal. Chem. 3 0 , 1 2 8 6 ( 1 9 5 8 )
Gradient Elution of Disaccharides on a Stearic Acid-Treated Charcoal Column
Gradient elution technique is applied in the separation of disaccharides having similar R/ values on a stearic acid-treated charcoal column. The method permits iso lation of disaccharides not separable by paper chroma tography, as turanose-sucrose, isomaltose-gentiobiose, maltulose-nigerose, and lactose-melibiose. NANCY HOBAN and J. W . WHITE, Jr., Eastern Regional Research Laboratory, Philadelphia 1 8, Pa. Anal. Chem. 3 0 , 1 2 9 4 ( 1 9 5 8 )
Precipitation of Cadmium Sulfide from Acid Solutions by Thioacetamide
The precipitation reaction of cadmium as sulfide by this acetamide is studied with respect to hydrogen ion con centration of solution. At pH 2 and lower, precipitation of cadium sulfide is primarily through hydrolysis of thio acetamide, while a direct reaction occurs at higher pH values. The rate of precipitation is decreased by pres ence of chloride ions. D. F. BOWERSOX and Ε. Η. SWIFT, California Institute of Technology, Pasadena, Calif.
Microdetermination
of Deuterium by
Effusiometry
Effusiometry is employed in a simple, rapid method for the determination of deuterium. Compounds containing deuterium are reduced to hydrogen-deuterium gas by treating with hot (500° C.) uranium turnings. Rate of effusion through a small opening is measured by a pair of thermistors. D. A. LEE, O a k Ridge National Laboratory, O a k Ridge, Tenn. Anal. Chem. 3 0 , 1 2 9 6 ( 1 9 5 8
Anal. Chem. 3 0 , 1 2 8 8 ( 1 9 5 8 )
Microdetermination of Carbon and Hydrogen in Pyrophoric and Hygroscopic Organic Compounds
Spectrophotometric Assay for Reaction of N-Ethylmaleimide with Sulfhydryl Groups
A spectrophotometric method for sulfhydryl groups is based on the reactivity with JV-ethylmaleimide at 300 πΐμ. In solution at pH 6, the absorption of iV-ethylmaleimide is diminished in proportion to its reaction with sulfhydryl groups. Purines, pyrimidines, and nu cleosides do not interfere. EUGENE ROBERTS and GEORGE Center, Duarte, Calif.
ROUSER, City of Hope
A simple, convenient technique employs polyethylene bags in the handling and weighing of microsamples of pyrophoric and hygroscopic organic compounds. The bags also protect against the absorption of atmospheric oxygen during transfer of the sample to a combustion tube for the determination of carbon and hydrogen. Ac curacy of the determinations is not improved.
Medical
W . P. PICKHARDT, L. W . SAFRANSKI, and J O H N MITCHELL, Jr., E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.
Anal. Chem. 3 0 , 1 2 9 1 ( 1 9 5 8 )
Anal. Chem. 3 0 , 1 2 9 8 ( 1 9 5 8 )
VOL.
30,
NO.
7,
JULY
1958
·
15
A
