A C BRIEFS

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A C BRIEFS Highlights of Articles in This Issue

Novel Peak Matching Technique by Means of a New and Combined Multiple Ion Detector-Peak Matcher Device. Elemental Analyses of Compounds in Submicrogram Quantities without Prior Isolation A combined multiple ion detector-peak matcher device for a gas ehromatograph-single focusing mass spectrometer al­ lowing elemental analyses of non-isolated compounds in submicrogram quantities during their elution from a GCcolumn. CARL-GUSTAF HAMMAR and RONNY HESSLING, Depart­ ment of Toxicology, Swedish Medical Research Council, Karolinska Institutet, S-104 01 Stockholm 60, Sweden Anal. Chem., 43, 298 (1971)

Ion Specific Detection of Internal Standards Labelled with Stable Isotopes Compounds labelled with stable isotopes appear to func­ tion as ideal internal standards when the mass-spectrometer is used as (he detector for gas chromatographic effluents. THOMAS E. GAFFNEY, CARL-GUSTAF HAMMAR, BO HOLMSTEDT, and ROBERT £. McMAHON, Department of Toxicology, Swedish Medical Research Council, Karolinska Institutet, 104 01 Stockholm 60, Sweden, and The Lilly Research Laboratories, Indianapolis, Ind. Anal. Chem., 43, 307 (1971)

Effects of Structure of Peptide Stationary Phases on Gas Chromatographic Separations of Amino Acid Enantiomers Asymmetry at the amide of a dipeptide derivative has been shown to be more important than at the ester end. Struc­ tural effects have been examined using a tripeptide and substituents of different types. J. A. CORBIN, J. E. RHOAD, and L. B. ROGERS, Depart­ ment of Chemistry, Purdue University, Lafayette, Ind. 47907 Anal. Chem., 43, 327 (1971) Low Level Sodium Ion Measurement with the Glass Electrode By using favorable instrumental factors and a selected base reagent, as explained, sodium can be monitored quite satis­ factorily down to the 0.1 ppb level. EDGAR L. ECKFELDT and WILLIAM E. PROCTOR, JR., Corporate Research Department, Leeds & Northrup Com­ pany, North Wales, Pa. Anal. Chem., 43, 332 (1971)

Spectrophotometric Assay of Ampicillin (α-Aminobenzylpenicillin) Involving Initial Benzoylation of the Side Chain α-Amino Group

Multivariate Analysis of Quantitative X-Ray Emission Data. The System Zirconium Oxide-Aluminum Oxide-Silicon Oxide-Calcium Oxide-Cerum Oxide

Ampicillin in assayed at concentrations as low as 4 X 10"BAf by benzoylation prior to acid-HgCl» treatment. The assay is especially useful for following degradation rate of drug.

Λ review and discussion of statistical methods for quanti­ tative X-ray emission analysis of multicomponent systems is presented. Ajiplication of the techniques to the system ZrCK-AbOs-SiOa-CaO-CeO» gave results accurate to about ± 1 to 2% relative.

DAVID E. TUTT and MICHAEL A. SCHWARTZ, Department of Pharmaceutics, School of Pharmacy, State University of New York at Buffalo, Buffalo, Ν. Υ. 14214.

DONALD A. STEPHENSON, Research and Development Laboratories, Corning Glass Works, Corning, Ν. Υ. 14830

Application of a Computerized Electrochemical System to Pulse Polarography at a Hanging Mercury Drop Electrode

Anal. Chem., 43, 310 (1971)

Anal. Chem., 43, 338 (1971)

Spectrophotometric Determination of Traces of Thallium in Tungsten. The Extraction of Thallium Diethyldithiocarbamate

Results of applying a computerized pulse polarography sys­ tem to trace analysis are described. Measurements are made at concentrations as low as 4 χ 10~8Μ Cd 2 .

The procedure for the determination of 0.1-10 ppm thallium is based on the extraction of thallium as diethyldithiocar­ bamate complex and on the determination with Methyl Violet witl) 10-20% relative standard deviation.

H. E. KELLER and R. A. OSTERYOUNG, Department of Chemistry, Colorado State University, Fort Collins, Colo. 80521 Anal. Chem., 43, 342 (1971)

KAROLY VADASDI, PIROSKA BUXBAUM, SALAMON, Research Institute for Technical Hungarian Academy of Sciences, Budapest, Anal. Chem.,

Rapid Analysis for Sub-Nanogram Amounts of Chromium in Blood and Plasma Using Electron Capture Gas Chromatography

and ANDRAS Physics of the Hungary 43, 318 (1971)

Liquid Ion Exchange Electrodes in Mixed Electrolyte Solutions The selectivity characteristics of the Orion Calcium Ac­ tivity electrode (92-20) in the aqueous systems CaCl 2 -MgCl» and CaCb-SrCb are presented together with the Harned co­ efficients estimated from measurements with this electrode and the Orion Chloride electrode (92-17). J. V. LEYENDEKKERS and MICHAEL WHITFIELD, Division of Fisheries and Oceanography, CSIRO, Cronulla, Sydney, 2230, Australia Anal. Chem., 43, 322 (1971)

Chromium in blood and plasma is simultaneously chelated with l,l,l-trimioiO-2,4-pentanedionc and extracted into hexane by direct reaction in a sealed tube. The chromium is then quantitatively determined by gas chromatography using a tritium detector. LARRY C. HANSEN and WILLIAM G. SCRIBNER, Monsanto Research Corporation, Dayton, Ohio 45407, T. WILLIAM GILBERT, Department of Chemistry, University of Cin­ cinnati, Cincinnati, Ohio 45221, and ROBERT E. SIEVERS, Aerospace Research Laboratories, Wright-Patterson Air Force Base, Ohio 45433 Anal. Chem., 43, 349 (1971) ANALYTICAL CHEMISTRY, VOL. 43, NO. 3, MARCH 1971

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A C BRIEFS Rapid Scan Infrared Spectrometer for Operation with Support Coated Open Tubular or Packed Column Gas Chromatographs

Application of Photoelectron Spectrometry to Pesticide Analysis. Photoelectron Spectra of Hydroxy-, and Halo-Alkanes and Halohydrins

An infrared spectrometer is described for recording spectra of gas liquid chromatographic fractions from cither packed or "SCOT" columns. Good quality spectra are obtained at the twenty microgram level.

The photoelectron spectra of several mono- and di-haloalkanes, alcohols, and ethylene halohydrins are reported and their theoretical and analytical significance is discussed.

R. A. BROWN, J. M. KELLIHER, and J. J. HEIGL, Esso Re­ search and Engineering Co., Linden, N. J., and C.W. WARREN, Instruments & Communications, Inc., Wilton, Conn. Anal. Chem., 43, 353 (1971)

Simple and Inexpensive Electronic Conductivity Manometer for Monitoring Pressure Changes. Application to Pressuremetric Titrations of lodate and Ammonium Ions Λ pressure transducer s\ - stem based on electronic monitor­ ing of the liquid level in a manometer is presented. Its use as an end point detection device in volumetric and coulomctric titrations is discussed. D. J. CURRAN and S. J. SWARIN, Department of Chem­ istry, University of Massachusetts, Amherst, Mass. 01002 Anal. Chem., 43, 358 (1971)

Near Optimum Computer Searching of Information Files Using Hash Coding Hash coding has been used to develop two algorithms for searching information files similar to those used in spec­ trometry laboratories. Search speeds up to 2000 spectra per second are obtained. PETER C. JURS, Department of Chemistry, The Pennsyl­ vania State University, University Park, Pa. 16802

A. D. BAKER, D. BETTER1DGE, N. R. KEMP, and R. E. KIRBY, Department of Chemistry, University College of Swansea, Singleton Park, Swansea, Qlam., U. K. Anal. Chem., 43, 375 (1971)

Computerized Learning Machine Applied to Qualitative Analysis of Mixtures by Stationary Electrode Polarography Qualitative resolution of stationary electrode polarographic data by a computerized learning machine has been evaluated. Categorization criteria were optimized by investigation of specific indontification errors made in unbiased training. L. B. SYBRANDT and S. P. PERONE, Department of Chem­ istry, Purdue University, Lafayette, Ind. 47907 Anal. Chem., 43, 382 (1971)

Determination of Hydrogen Sulfide, Sulfur Dioxide, Carbonyl Sulfide, Carbon Disulfide, and Carbon Dioxide in a Gas Mixture The separation and determination of components of a gas mixture absorbed in solutions of copper sulfate and cthanolic potassium hydroxide are presented. Better than 3 % ac­ curacy is possible. ARTHUR SCHWARTZ, Development Center, Chemical Con­ struction Corporation (CHEMICO), New Brunswick, N. J. 08903 Anal. Chem., 43, 389 (1971)

Anal. Chem., 43, 364 (1971)

Teflon, a Noninert Chromatographic Support Teflon is not an inert support as sometimes supposed. A two-site sorption mechanism describes the substantial sorp­ tion of both polar and nonpolar solutes observed with varying loadings of di-?i-nonyI phthalatc. J. R. CONDER, Chemical Engineering College of Swansea, United Kingdom

Dept.,

University

Anal. Chem., 43, 367 (1971)

Molecular and Unit Sheet Weights of Asphalt Fractions Separated by Gel Permeation Chromatography Vapor pressure osmometry molecular weight determina­ tions are shown to be solvent dependent. This affects the calibration of gel permeation chromatograms and the cor­ relation of molecular and unit sheet weights. GRAEME A. HALEY, School of Highway Engineering, Uni­ versity of New South Wales, Box 1, Kensington 2033, N.S.W. Australia Anal. Chem., 43, 371 (1971)

Simultaneous Determination of Two Electroactive Species by Alternating Current Polarography The possibility of quantitatively determining two species which produce overlapping polarographic waves by the ac technique at the dropping mercury electrode has been examined. A. M. BOND and J. H. CANTERFORD, Department of In­ organic Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia Anal. Chem., 43, 393 (1971)

A Laboratory-Based Computer System A real-time computer system has been implemented in a laboratory research environment. Data are collected by the computer from remotely located instruments simultaneously with other computer processing. MARVIN SHAPIRO and ARTHUR SCHULTZ, National In­ stitutes of Health, Bethesda, Md. Anal. Chem., 43, 398 (1971) ANALYTICAL CHEMISTRY, VOL. 43, NO. 3, MARCH 1971 ·

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A C BRIEFS Digital Methods of Photopeak Integration in Activation Analysis

Notes

Λ study has boon carried out of the relative precisions which are attainable by seven digital methods of photopeak inte­ gration, in activation analysis experiments involving gammaray spectrometry.

Kinetics and Mechanism of Extraction of Iron(lll) with /; Isopropyltropolone

PHILIP A. BAEDECKER, Department of Chemistry and In­ stitute of Geophysics and Planetary Physics, University of California, Los Angeles, Calif. 90024 Anal. Chem., 43, 405 (1971) Potentiometric Studies with an Ion Permselective Membrane A membrane electrode is described that can be used for redox, precipitation, complexometrie, acid-base, and non­ aqueous potentiometric titrations. It exhibits varying de­ grees of permselectivity to cations and anions and is stable for several months. SUDARSHAN LAL and GARY D. CHRISTIAN, Department of Chemistry, University of Kentucky, Lexington, Ky. 40506 Anal. Chem., 43, 410 (1971) Use of Syringaldazine in a Photometric Method for Estimating " F r e e " Chlorine in Water Syringaldazine buffered at p H 7 has been used in a photometric procedure for estimating "free" chlorine. The procedure can detect chlorine in concentrations of 0.05 ± 0.011 ppm and is not affected by chloramin.es. ROBERT BAUER and CHAUNCEY 0. RUPE, Ames Com­ pany, Division of Mites Laboratories, Inc., Elkhart, Ind. 46514 Anal. Chem., 43, 421 (1971) Intrinsic End-Point Errors in Precipitation Titrations with Ion Selective Electrodes The effect of finite interference ratios on the analytical precision and accuracy of a variety of potentiometric pre­ cipitation titrations is presented. Results are discussed in terms of selectivity and symmetry errors. PETER W. CARR, Department Georgia, Athens, Ga. 30601

of Chemistry, University of Anal. Chem., 43, 425 (1971)

Determination of the Formation Constants of Iron(lll) and Vanadium(V) with β-lsopropyltropolone Using the Extraction Method Equilibrium constants in the extraction of ferric and vanadyl chelates with /3-isopropyltropolone were obtained from graphical and least square calculations of data. An adduct formation of V O J P T H T P T is reported for the first time from the extraction data. OSCAR MENIS, B. E. McCLELLAN, and DAVID S. BRIGHT, Analytical Chemistry Division, National Bureau of Stan­ dards, Washington, D. C. 20234 Anal. Chem., 43, 431 (1971)

A study of the kinetics and mechanism of the reaction be­ tween F c ( I I I ) and /3-isopropyltroprolone was made by the extraction method. The reaction orders in metal ion and reagent were found to be unity, and the addition of the first ligand to the F e ( I I I ) is postulated to be rate deter­ mining. Β. Ε. McCLELLAN and OSCAR MENIS, Analytical Chemis­ try Division, National Bureau of Standards, Washington, D. C. 20234 Anal. Chem., 43, 436 (1971) Determination of Nitrogen and Hydrogen at Parts-per-Million Levels in Milligram Steel Samples This micro-inert gas fusion technique yields one σ relative standard deviations of about 10% for the two elements and requires 90 minutes for a complete analysis. G. L. HARGROVF, R. C. SHEPARD, and HARRY FARRAR (V, Atomics international, A Division of North American Rockwell Corporation, Canoga Park, Calif. 91304 Anal. Chem., 43, 439 (1971) Novel Method of Determining Weak Bases in Small Amounts Weak bases (Ki, up to ΙΟ"10) can be determined in the /miole range by measuring the difference between the quantity of hydrogen chloride added to and that recovered from a saturated aqueous lithium chloride solution. ELIO SCARANO, MARCO MASCINI, and GIOVANNI GAY, institute of Analytical Chemistry, Faculty of Pharmacy, University of Genoa, Italy Anal. Chem., 43, 442 (1971) Improved Method for Determination of Chlorinated Hydrocarbon Pesticide Residues in Whole Blood An improved technique is presented that, increases the ac­ curacy and precision of the determination of chlorinated hydrocarbon residues in whole blood. The length of time necessary for analysis is also decreased. S. J. Henderson, J. G. DeBOER, and H. M. STAHR, Veteri­ nary Diagnostic Laboratory, Iowa State University, Ames, Iowa 50010 Anal. Chem., 43, 445 (1971) Quantitative Cation Exchange Separation of Zirconium and Hafnium in Formic Acid Media Zirconium has been quantitatively separated from hafnium on Dowex 50 W-X8 column by eluting with \M H C O O H and 4.0.1/ ΗΧΟ., respectively. Kd values for these 2 cations have been obtained in (0.1M-2QM) formic acid solutions on this resin. MOHSIN QURESHI and KHADIM HUSAIN, Chemistry De­ partment, Aligarh Muslim University, Aligarh, India Anal. Chem., 43, 447 (1971) ANALYTICAL CHEMISTRY, VOL. 43, NO. 3, MARCH 1971

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A C BRIEFS Plutonium Determination in Soil by Leaching and Ion-Exchange Separation

Analysis of Polyethylene Terephthalate Prepolymer by Trimethylsilylation and Gas Chromatography

Plutonium was measured in 100 grams of soil by leaching, ion-exchange, and alpha spectrometry. Average recovery was about 60%, and the results were comparable with com­ plete solution methods.

A method for the determination of ethylene glycol, diethylene glycol, terephthalic acid, and both mono- and bis-(2-hydroxyelhyl) terephthalate in polyethylene tereph­ thalate prepolymers was developed. The precision and accuracy were within 10% for each compound.

NORTON Y. CHU, Health and Safety Laboratory, Atomic Energy Commission, New York, Ν. Υ. 10014

U. S.

Anal. Chem., 43, 449 (1971) Isothermal Gas Chromatographic Separation of Carbon Dioxide, Carbon Oxysulfide, Hydrogen Sulfide, Carbon Disulfide, and Sulfur Dioxide A gas chromatographic column has been developed which enables the simultaneous separation and analysis of sulfur gases. This column was prepared from acid washed "Deactigel." WILLIS L. THORNSBERRY, JR., Research and Develop­ ment Laboratory, Freeport Sulphur Company, Belle Chasse, La. 70037 Anal. Chem., 43, 452 (1971) Optimization of Experimental Conditions for Spectrofluorimetric Determination of Europium, Samarium, and Terbium as Their Hexafluoroacetylacetone—Trioctylphosphine Oxide Complexes The effect of p H on (he fluorescence of the hcxafluoroacetylacetone/fri-M-octylphosphine oxide complexes of europium, samarium, and terbium was studied and optimum experi­ mental conditions for analysis of these rare earths were determined. R. P. FISHER and J. D. WINEFORDNER, Department of Chemistry, University of Florida, Gainesville, Fla. 32601 Anal. Chem., 43, 454 (1971) Kinetic Study of the Beckmann Rearrangement of 6-a-Methyl-17 a-Acetoxyprogesterone-3-Oxime by Cathode Ray Polarography The kinetic of Beckmann rearrangement was followed by polarography. I t was observed that the polarographic method can be used to calculate the syn and a-nti isomers of steroidal oximes. ARVIN P. SHROFF and CHARLES J. SHAW, Analytical Re­ search Group, Division of Organic Chemistry, Ortho Re­ search Foundation, Raritan, N. J. 08869 Anal. Chem., 43, 455, (1971)

E. R. ATKINSON, JR., and S. I. CALOUCHE, Analytical and Chemical Section, Firestone Synthetic Fibers Company, Box 450, Hopewell, Va. 23860 Anal. Chem., 43, 460 (1971)

Gas-Liquid Chromatography of Some Irritants at Various Concentrations Methods are described for determining a-bromobenzylnitrile (CA), o-chlorobcnzalmalononitrile (CS) and a-chloroacelophenone ( C N ) . For quality control, the accuracy is within ± 1 % . Vapor concentrations as low as 0.1 mg/m 3 can be measured. SAMUEL SASS, TIMOTHY L. FISHER, MICHAEL J. JASCOT, and JOHN HERBAN, Chemical Research Laboratory, Re­ search Laboratories, Edgewood Arsenal, Edgewood Ar­ senal, Md. 21010 Anal. Chem., 43, 462 (1971) Suppression of Interferences by Sodium Sulfate in Trace Chromium Analyses by Atomic Absorption Spectrometry The presence of 1% Na^SOi in samples to be analyzed for trace amounts of chromium by atomic absorption spec­ trophotometry will eliminate the interferences caused by large amounts of contaminants. J. A. HURLBUT and C. D. CHRISWELL, Department of Chemistry, Metropolitan State College, Denver, Colo. 80204 Anal. Chem., 43, 465 (1971) Separation of Perrhenate, Molybdate, and Selenite Ions on Silica Gel The rapid separation of the above anions is described and the influence of solvent system and the T L C medium is presented. ALAN M. PHIPPS, Raytheon Co., MPT Division, Waltham, Mass. Anal. Chem., 43, 467 (1971)

Spectrophotometric Determination of Cobalt with Benzil Mono-(2-Pyridyl)Hydrazone

Fluorometric Determination of Submicrogram Quantities of Zirconium

A spectrophotometric determination of cobalt, based upon the absorbanec of a C o L / complex at 535 nm (e = 27,400), is described. The method without- separation is accurate for traces of cobalt.

A fluorometric method for zirconium using 3,4',7-trihydroxyflavone in a sulfuric acid solution has a detection limit of 0.05 /xg, a precision to about l'/r on 5 ,ttg, and excel­ lent tolerance to most common elements.

RONALD T. PFLAUM and E. SCOTT TUCKER III, Depart­ ment of Chemistry, University of Iowa, Iowa City, Iowa

T. D. FILER, Health Services Laboratory, U. S. Atomic En­ ergy Commission, Idaho Falls, Idaho

Anal. Chem., 43, 458 (1971)

Anal. Chem., 43, 469 (1971) ANALYTICAL CHEMISTRY, VOL. 43, NO. 3, MARCH 1971

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A C BRIEFS Liquid-Liquid Extraction of Rhenium(VII) with Mesityl Oxide About 25 μί; was extracted from 1M hydrochloric acid and potassium chloride. Rhenium was subsequently determined photometrically as the thiocyanatc complex. V. M. SHINDE and S. M. KHOPKAR, Department of Chem­ istry, Indian Institute of Technology, Bombay-76, India Anal. Chem., 43, 473 (1971) Emission Spectrochemical Determination of Tantalum in Curium Oxide A spectrochemical method for the determination of tanta­ lum in curium oxide is described. The tantalum is separated from the curium oxide matrix by fusing with potassium carbonate, dissolving the melt in HC1-HF mixture, and isolating the tantalum by solvent extraction. R. H. GADDY, Savannah River Laboratory, E. I. du Pont de Nemours & Co., Aiken, S. C. 29801 Anal. Chem., 43, 475 (1971) Novel Technique for Surface Analysis of Solid Metallic Specimens Using Selected Anodic Current-Voltage Characteristics Corroding alloys exhibit anodic current maxima whicli can be a function of chemical composition only. Measurement of several such maxima enables an analysis of the alloy surface to be obtained. GEORGE TODD and G. A. WILD, Royal Armament Research and Development Establishment, Fort Halstead, England Anal. Chem., 43, 476 (1971) Boron-Polyethylene Irradiation Containers for High Energy Neutron Activation Analysis Polyethylene-boron irradiation containers were evaluated for fast, neutron activation. Employed with cadmium shielding, they resulted in as much as two orders of magni­ tude reduction (η/γ) thermal and resonance neutron ac­ tivation. W. A. JESTER and Κ. Ν. PRASAD, Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pa. 16802 Anal. Chem., 43, 481 (1971) Determination of Iron by EDTA Titrimetry of the Thiocyanate Complex A highly seleclive method for iron is obtained by combining isoamyl alcohol extraction of iron(III)-thiocyanatc with E D T A titration at p H 2-3. Good precision is maintained down to 50 ftg. ANTONIO DE A. FIGUEIREDO, Instituto de Tecnologia Alimenter, Rua Jardim Botanico, 1024, ZC-20, Rio de Janeiro, Brasil Anal. Chem., 43, 484 (1971) Confirmation of High Aromaticity of Anthracite by Broadline Carbon-13 Magnetic Resonance Spectrometry Broadline Carbon-13 magnetic resonance^ spectra of Dorranee anthracite (92.7Çf carbon) and solid adamantane are presented and discussed in terms of the chemical structure of the former.

New Method for Separation of Americium from Curium and Associated Elements in the Zirconium Phosphate-Nitric Acid System A new, simple method is described for the rapid separation of americium from curium, other actinidc elements, lanthanidc elements, and cesium. The method is based on our recent observation of the negligible sorbability of Am(A) on the cation exchanger, zirconium phosphate, from dilute nitric acid. FLETCHER L. MOORE, Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tenn. Anal. Chem., 43, 487 (1971)

Aids for Analytical Chemists Rapid and Efficient Method for Removing Viscous Polymer Solutions from NMR Sample Tubes ALEX JAKAB, Research Division, Goodyear Tire and Rubber Co., Akron, Ohio 44316 Anal. Chem., 43, 489 (1971) Simple Device for Transferring Thin-Layer Chromatographic Fractions for Spectroscopic Examination COLIN J. CLEMETT, Unilever Research, Port Sunlight Laboratory, Port Sunlight, Wirral, Cheshire, L.62 4XN, U. K. Anal. Chem., 43, 490 (1971) Modulated Power Unit for Driving Metal Vapor Discharge Lamps F. M. HAMM, T. L. MARTIN, and P. Β. ΖΕΕΜΑΝ, Depart­ ment of Physics, University of Stellenbosch, South Africa Anal. Chem., 43, 490 (1971) Simple Continuous Electronic Readout for Rotameter-Type Fluid Flow Measuring Devices Using a Photoelectric Transducer SEYMOUR LOWELL and STEWART KARP, C. W. Post Col­ lege, Long Island University, Greenvale, Ν. Υ. 11548 Anal. Chem., 43, 492 (1971) Low Cost Parallel-to-Serial Converter for Digital Instrumentation MORTEZA JANGHORBANI, JOHN A. STARKOVICH, and HARRY FREUND, Department of Chemistry, Oregon State University, Corvallis, Ore. 97331 Anal. Chem., 43, 493 (1971) Ceramic Pressure Device for Preparation of Known Gas Concentrations at the 100 Parts-per-Million Level

H. L. RETCOFSKY and R. A. FRIEDEL, U. S. Department of the Interior, Bureau of Mines, Pittsburgh Energy Research Center, 4800 Forbes Ave., Pittsburgh, Pa. 15213

HERMAN D. AXELROD, RONALD J. TECK, and JAMES P. LODGE, JR., National Center for Atmospheric Research, Boulder, Colo. 80302 and RAYMOND H. ALLEN, R. H. Allen Co., Boulder, Colo. 80302

Anal. Chem., 43, 485 (1971)

Anal. Chem., 43, 496 (1971) ANALYTICAL CHEMISTRY, VOL. 43, NO. 3, MARCH 1971

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