A C BRIEFS Highlights of Articles in This Issue
Computerized Learning Machines Applied to Chemical Problems. Investigation of Convergence Rate and Predictive Ability of Adaptive Binary Pattern Classifiers The effect of several factors on the predictive ability and convergence rate of learning machines is investigated. P. C. JURS, B. R. KOWALSKI, and T. L. ISENHOUR, Department of Chemistry, University of Washington, Seattle, Wash. 98105, and C. N. REILLEY, Department of Chemistry, University of North Carolina, Chapel Hill, N.C. Anal. Chem., 4 1 , 690 (1969) Computerized Learning Machines Applied to Chemical Problems. Multicategory Pattern Classification by Least Squares The power of recognition and the predictive ability of pattern classifiers for multicategory problems drawn from low resolution mass spectrometry are evaluated. B. R. KOWALSKI, P. C. JURS, and T. L. ISENHOUR, Department of Chemistry, University of Washington, Seattle, Wash. 98105, and C. N. REILLEY, Department of Chemistry, University of North Carolina, Chapel Hill, N.C.
Correction and Simulation of Polychromatic Optical Spectra The method presented efficiently corrects spectra and tests the results. Accurate corrections can be expected if the ratio of spectral band-width to peak-width in less than 0.5. J. R. MORREY, Battelle-Northwest Laboratories, Battelle Memorial Institute, Richland, Wash. 99352 Anal. Chem., 4 1 , 719 (1969) Continuous Semi-Automatic Reaction Rate Measuring Instrument for Kinetic Based Analyses The system described is a high stability, low noise spectrophotometer designed primarily for continuous rate measurement. Factors controlling accuracy, linearity, and electronic response are discussed. THEODORE E. WEICHSELBAUM, WILLIAM H. PLUMPE, Jr., RAYMOND E. ADAMS, and JOHN C. HAGERTY, Sherwood Medical Industries Inc., St. Louis, Mo. 63103, and HARRY B. MARK, Jr., Department of Chemistry, The University of Michigan, Ann Arbor, Mich. 48104 Anal. Chem., 4 1 , 725 (1969)
Anal. Chem., 4 1 , 695 (1969) Q-Switched Laser Energy Absorption in the Plume of an Aluminum Alloy Time- and spatially-resolved spectrometric observations were made of single and multiple spike, Q-switehed laser plumes that are to be used for analytical procedures. E. H. PEIPMEIER and H. V. MALMSTADT, Department of Chemistry and Chemical Engineering, University of Illinois, Urbana, III. 61803 Anal. Chem., 4 1 , 700 (1969)
Theory of Polarographic Kinetic Currents for Second-Order Regeneration Reactions at Spherical Electrodes. I. Numerical Solution of Finite-Difference Equations Determination of rate constants for very rapid reactions at conveniently long times is possible because the response in the asymptotic region is controlled by both kinetic and divergent diffusion properties. D. T. PENCE, J. R. DELMASTRO, and G. L. BOOMAN, Idaho Nuclear Corporation, Idaho Falls, Idaho Anal. Chem., 4 1 , 737 (1969)
Determination of Atmospheric Concentrations of Sulfuric Acid Aerosol by Spectrophotometry, Coulometry, and Flame Photometry The acid is thermally decomposed at 400 °C, converted to sulfur dioxide, and detected by either of three systems.
Theory of Polarographic Kinetic Currents for Second-Order Regeneration Reactions at Spherical Electrodes. II. Numerical Solution of the Integral Equation for Steady-State Behavior
F. P. SCARINGELLI and K. A. REHME, National Air Pollution Control Administration, 4676 Columbia Parkway, Cincinnati, Ohio 45226
Numerical results demonstrate that the upper limit of ik/iD is less than two and is highly dependent on the effective electrode sphericity.
Anal. Chem., 4 1 , 707 (1969) Comparative Study of Premixed and Turbulent Air-Hydrogen Flames in Atomic Fluorescence Spectrometry The turbulent flame results in greater or comparable sensitivities and only slightly greater scattering signals as compared to premixed flames. M. P. BRATZEL, Jr., R. M. DAGNALL, and J. W. WINEFORDNER, Department of Chemistry, University of Florida, Gainesville, Fla. 32601 Anal. Chem., 4 1 , 713 (1969)
JOSEPH R. DELMASTRO, Idaho Falls, Idaho 83401
Idaho
Nuclear
Corporation,
Anal. Chem., 4 1 , 747 (1969) Electrochemistry of 8,8 -Diquinolyldisulfide The electrochemistry of 8,8'-diquinolyldisumde and mercuric thiooxinate is studied in aqueous and methanolic solution using a variety of techniques. JOHN J. DONAHUE and JOHN W. OLVER, Department of Chemistry, University of Massachusetts, Amherst, Mass. Anal. Chem., 4 1 , 753 (1969) VOL. 4 1 , NO. 6, MAY 1969
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Controlled-Potential Coulometry and Voltammetry of Manganese in Pyrophosphate Medium
Analysis of Microsamples by Single-Exposure Spark Source Mass Spectrometry
Oxidation of M n ( I I ) to M n ( I I I ) in N a 4 P 2 0 7 solution of p H 2 is studied. Milligram amounts of M n are determined with few interferences and an accuracy and precision of 0.1%.
Impurity concentrations over a range > 10 4 : 1 were de termined by measuring the image broadening caused by the turbity effect. Secondary ion fogging did not interfere.
J. E. HARRAR and L. P. RIGDON, Chemistry Department, Lawrence Radiation Laboratory, University of California, Livermore, Calif. 94550
PHILIPPE CHASTAGNER, Savannah River Laboratory, E. I. du Pont de Nemours and Co., Aiken, S. C. 29801 Anal. Chem., 4 1 , 796 (1969)
Anal. Chem., 4 1 , 758 (1969)
Separation of Crude Oil Fractions by Gel Permeation Chromatography
Polarography in Sulfolane and Reference of Potentials in Sulfolane and Other Nonaqueous Solvents to the Water Scale
High-boiling petroleum fractions are separated by G P C with polystyrene gel and benzene solvent without the thermal hazards of distillation.
Polarographic half-wave potentials of alkali metals in sulfolane are measured, and results are used to modify the Born equation to compare potentials in sulfolane, several nitriles, acetone, and water.
H. J. COLEMAN, D. E. HIRSCH, and J. E. DOOLEY, Bartlesville Petroleum Research Center, Bureau of Mines, U. S. Department of the Interior, Bartlesville, Okla.
J. F. COETZEE, J. M. SIMON, and R. J. BERTOZZI, Department of Chemistry, University of Pittsburgh, Pitts burgh, Pa. 15213 Anal. Chem., 4 1 , 766 (1969) Solid-State Controlled-Potential D.C. Polarograph Cyclic Scanning and Calibrated First- and Second-Derivative Scales
with
A versatile, reliable d.c. polarograph having a current range of 0.02 μΑ to 10 μΑ and precision scan rates (S < 0.1%) from 0.1 to 10 V/min is described. H. C. JONES, W. L. BELEW, R. W. STELZNER, T. R. MUELLER, and D. J. FISHER, Analytical Chemistry Divi sion, Oak Ridge National Laboratory, Oak Ridge, Tenn. 37830 Anal. Chem., 4 1 , 772 (1969) Apparatus for Precision Control of Drop Time of Dropping Mercury Electrode in Polarography Precise electromechanical control of drop time for a D M E at values from 0.25 to 10 sec is possible with the apparatus. W. L. BELEW, D. J. FISHER, H. C. JONES, and M. T. KELLEY, Analytical Chemistry Division, Oak Ridge Na tional Laboratory, Oak Ridge, Tenn. 37830
Anal. Chem., 4 1 , 800 (1969) Chlorine Isotopic Ratios by Negative Ion Mass Spectrometry The method shows that nonquantitative preparation of the mass spectrometer methyl chloride sample resulted in fractionation of the chlorine isotopes. JAMES W. TAYLOR and ERIC P. GRIMSRUD, Department of Chemistry, The University of Wisconsin, Madison, Wis. Anal. Chem., 4 1 , 805 (1969) Role of Induction Forces Interactions in Effecting Gas Chromatographic Separation of Cardiac Glycoside Trimethylsilyl Ethers Gas chromatographic separation of TMSi ethers of digitoxin, digoxin, and gitoxin was effected at 340°C on OV-17. W. E. WILSON and J. E. RIPLEY, Biochemistry Section, Southern Research Support Center, Veteran's Administra tion Hospital, Little Rock, Ark. 72206 Anal. Chem., 4 1 , 810 (1969) Continual Analysis of Gas Chromatographic Effluents by Rapid Repetitive Infrared Scanning Rapid on-the-fly infrared analysis of GC effluents is in vestigated. Spectra obtained are adequate for functional group analyses and detection of unresolved GC peaks.
Anal. Chem., 4 1 , 779 (1969)
BURTON KRAKOW, The Warner & Swasey Co., Control Instrument Div., 3 2 - 1 6 Downing St., Flushing, Ν. Υ.
Preparative Thin-Layer Chromatography and High Reso lution Mass Spectrometry of Crude Oil Carboxylic Acids
Anal. Chem., 4 1 , 815 (1969)
A fraction representing 5% of petroleum has been isolated Mass spectra of the acids and indicate classes ranging from Ζ =
the acids in a California by combined techniques. their fluoroalcohol esters + 2 and Ζ = — 26.
WOLFGANG K. SEIFERT, Chevron Oil Field Research Co., P.O. Box 1627, Richmond, Calif. 94802, and RICHARD M. TEETER, Chevron Research Co., Richmond, Calif. 94802 Anal. Chem., 4 1 , 786 (1969)
Activation Analysis of Halogens in Photographic Emulsions Using a Neutron Generator Rapid analytical methods are developed for chloride and iodide determinations with precisions comparable to those from existing chemical methods. E. P. PRZYBYLOWICZ, GILBERT W. SMITH, J. E. SUDDUETH and S. S. NARGOLWALLA, Inst, for Materials Research, National Bureau of Standards, Washington, D.C. Anal. Chem., 4 1 , 819 (1969) VOL. 4 1 , NO. 6, MAY 1969
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Effect of Selected Solvents on the Viscosities and Oxygen Contents of Asphalts
Determination of Iron at Parts-per-Billion Levels by Quenching of 2,2'2"-Terpyridine Luminescence
Six asphalts were each dissolved in four solvents and the asphalts recovered. Benzene and benzene—ethanol blends cause only minor changes in viscosity.
T h e basis of the method is the formation of a nonluminescent chelate [ F e ( I I ) - ( 2 , 2', 2"-terpyridine)l| + . The intense luminescence of the ligand is decreased in proportion to the amount of iron added.
M. A. ABU-ELGHEIT, C. K. HANCOCK, and R. N. TRAXLER, Highway Research Center, Texas A&M University, College Station, Texas 77843 Anal. Chem., 4 1 , 823 (1969)
DAVID W. FINK, JAMES V. PIVNICHNY, and WILLIAM E. OHNESORGE, Department of Chemistry, Lehigh University, Bethlehem, Pa. 18015 Anal. Chem., 4 1 , 833 (1969)
Notes Oxygen Distribution in Asphalts Used for Bituminous Paving Samples from 13 roads made with different aggregates were used in this investigation. Oxygen content of the samples varied from 0.30 to 1.05 wt '%. R. N. TRAXLER, W. E. KUYKENDALL, and J. S. HISLOP, Highway Research Center, Texas A&M University, College Station, Texas 77843
Application of Infrared Internal Reflection Spectrometry to Studies of the Electrochemical Reduction of Carbonyl Compounds Absorption of the p-benzoquinone radical anion is detected during electrolysis of dilute (10 τιΜ) quinone solutions, and the absorbance is correlated with the electrode potential. DAVID R. TALLANT and DENNIS H. EVANS, Department of Chemistry, University of Wisconsin, Madison, Wis. 53706 Anal. Chem., 4 1 , 835 (1969)
Anal. Chem., 4 1 , 827 (1969) Quantitative Infrared Determination of Ammonium Ion in Hydroxylamine Sulfate T h e method uses the Ν—Η deformation band of the am monium ion at 1400 cm - 1 . High results observed by other methods are avoided with this technique. EVERETT S. WHITEHEAD, Industrial Laboratory, Eastman Kodak Co., Rochester, Ν. Υ. 14650 Anal. Chem., 4 1 , 829 (1969)
Determination of Amino Hydrogen in Water. Application to Residual Chlorine Analysis Amino hydrogen from ammonia and primary aliphatic amines in water is determined and differentiated from secondary amine amino hydrogen by controlled hypo chlorite chlorination and spectrophotometric iodimetry. JACK L. LAMBERT and JORGE OLGUIN, Department of Chemistry, Kansas State University, Manhattan, Kansas 66502 Anal. Chem., 4 1 , 838 (1969)
Use for X-Ray Spectrometry of the (200) Reflection of Ammonium Dihydrogen Phosphate In addition to the (101) reflection of ADP, the (200) reflec tion provides a useful 2d spacing of 7.50 Â. This cut is particularly good for the 5—7 Â region and for shift and shape measurements on SiK lines and bands. WILLIAM L. BAUN, Materials Physics Division (MAYA), Air Force Materials Laboratory, Wright-Patterson Air Force Base, Ohio Anal. Chem., 4 1 , 830 (1969) Clinochlore: A Versatile New Analyzing Crystal for the X-Ray Region 5 - 2 7 A Use of the chlorite minerals particularly clinochlore, 2d = 28.392 Â, as analyzing crystals for soft X-rays is discussed. Crystal advantages and properties are presented and compared with K A P .
Mass Spectrometric Method for Determination of Subnanogram Quantities of Neptunium-237 235 Np and 2 3 6 Np have been prepared by deuteron bombard ment of 2 3 5 U and used as isotopic diluents for determination of subnanogram levels of 2 3 7 Np by mass spectrometric analysis.
JERRY H. LANDRUM, MANFRED LINDNER and NANCY JONES, Lawrence Radiation Laboratory, University of California, Livermore, Calif. 94550 Anal. Chem., 4 1 , 840 (1969)
Analysis of Organic Sulfides by Titration of Their Hydrogen Peroxide-Formed Sulfoxide Ten repetitive analyses of a pure organic sulfide gave 97.9% of theory with a standard deviation of 0.20. Other sulfides, including a thioester and a thioalcohol, gave from 95 to 99% of theory.
W. L. BAUN, Materials Physics Division (MAYA), Air Force Materials Laboratory, Wright-Patterson Air Force Base, Ohio 45433, and E. W. WHITE, Materials Research Laboratory, The Pennsylvania State University, University Park, Pa. 16802
CHARLES B. PUCHALSKY, Uniroyal Chemical, Division of Uniroyal, Inc., Naugatuck, Conn.
Anal. Chem., 4 1 , 831 (1969)
Anal. Chem., 4 1 , 843 (1969) VOL. 4 1 , NO. 6, MAY 1969
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Polarographic Reduction of the Molybdate-Chlorate System in Biphthalate Medium
Spectrophotometric Determination of Dissolved Oxygen in Water
In biphthalate medium, M o ( V I ) produces a wave involving one electron and two protons.
The method uses the trans 1,2-diaminocyclohexanetetraacetic acid complex of M n ( I I I ) .
DEMETRIOS KYRIACOU, Research Laboratories, The Dow Chemical Co., Pittsburg, Calif. 94565
G. S. SASTRY, R. Ε. ΗΑΜΜ, and Κ. Η. POOL, Chemistry Department, Washington State University, Pullman, Wash. 99163
Anal. Chem., 4 1 , 844 (1969)
Anal. Chem., 4 1 , 857 (1969) Electron Microprobe Investigation of Oxide Films on Platinum-lridium Electrodes Results obtained in using an electron probe X-ray microanalyzer to investigate the oxygen contents of films formed on surfaces of platinum-iridium foil electrodes are given. ARTHUR A. CHODOS, Division of Geological Sciences, California Institute of Technology, Pasadena, Calif. 91109, and LOUIS MEITES, Department of Chemistry, Clarkson College of Technology, Potsdam, Ν. Υ. 13676
Spectrophotometric Determination of the Hydroxypropyl Group in Starch Ethers Of the two methods described in this paper, the first is designed for hydroxypropyl group concentrations of 1% or more ; the second is intended for lower concentrations. D. P. JOHNSON, Product Development Center, R. J. Reynolds Tobacco Company, Winston-Salem, N. C. Anal. Chem., 4 1 , 859 (1969)
Anal. Chem., 4 1 , 846 (1969) Reaction Rate Method for Ammonia and Blood Urea Nitrogen Utilizing a Pentacyanonitrosyloferrate Catalyzed Berthelot Reaction T h e nature of the kinetic behavior of the reaction, the choice of optimum catalyst concentration, and typical analytical results are discussed. THEODORE E. WEICHSELBAUM and JOHN C. HAGERTY, Sherwood Medical Industries Inc., St. Louis, Mo. 63103, and HARRY B. MARK, Jr., Department of Chemistry, Uni versity of Michigan, Ann Arbor, Mich.
A Recommended Titrant: Anhydrous Perchloric Acid In Sulfolane Essentially anhydrous solutions of perchloric acid, prepared in sulfolane as solvent, are highly acidic and should have considerable analytical potentialities. J. F. COETZEE and R. J. BERTOZZI, Department of Chem istry, University of Pittsburgh, Pittsburgh, Pa. 15213 Anal. Chem., 4 1 , 860 (1969)
Correspondence
Anal. Chem., 4 1 , 848 (1969) Double Potential Step Method for Measuring Rate Constants of Dimerization Reactions Theoretical data are presented for use of the title method to measure rate constants for dimerization reactions initi ated electrolytically. MICHAEL L. OLMSTEAD and RICHARD S. NICHOLSON, Chemistry Dept., Michigan State University, East Lansing, Mich. 48823 Anal. Chem., 4 1 , 851 (1969) Rapid Group Radiochemical Separations for Activation Analysis of Steels Precise and accurate determination of Cu, Co, Cr, As, W, Mo, Sb, and Ga in NBS Standard Reference Material steel and cast iron is described.
Cyclic Voltammetry Theory for the Disproportionation Reaction and Spherical Diffusion MICHAEL L. OHMSTEAD and RICHARD S. NICHOLSON, Chemistry Department, Michigan State University, East Lansing, Mich. 48823 Anal. Chem., 4 1 , 862 (1969)
Aids for Analytical Chemists Continuous Measurement of Mass Transport across Membranes CARTER L. OLSON, THEODORE D. SOKOLOSKI, SHRIKANT N. PAGAY, and DAVID MICHAELS, College of Phar macy, The Ohio State University, Columbus, Ohio 43210 Anal. Chem., 4 1 , 865 (1969)
BARBARA A. THOMPSON and PHILIP D. LAFLEUR, Ana lytical Chemistry Division, National Bureau of Standards, Washington, D. C. 20234
A Controlled Atmosphere Cell for Rotating Disk Electrode Voltammetry in Fused Salts
Anal. Chem., 4 1 , 852 (1969)
PIER GIORGIO ZAMBONIN, Department of Chemistry, The Pennsylvania State University, University Park, Pa. 16802
Determination of Micro and Semimicro Amounts of Aluminum Using Fluoride Activity Electrode Aluminum in the range of 60 ^g to 3 mg per 25 ml is deter mined by a direct potentiometric method using a fluoride activity electrode and fluoride as a titrant.
Anal. Chem., 4 1 , 868 (1969) Gas Chromatographic Separation of Chlorosilanes, Methylchlorosilanes, and Associated Siloxanes
BRUNO JASELSKIS and MARY K. BANDEMER, Depart ment of Chemistry, Loyola University, Chicago, III.
K. RAY BURSON, Texas Instruments, Inc., P. O. Box 5012, Dallas, Texas, and CHARLES T. KENNER, Department of Chemistry, Southern Methodist University, Dallas, Texas
Anal. Chem., 4 1 , 855 (1969)
Anal. Chem., 4 1 , 870 (1969)
Circle No. 61 on Readers' Service Card
VOL. 4 1 , NO. 6, MAY 1969
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