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Activity coefficients of choline chloride obtained with a choline ion-selective electrode agree with those derived by the isopiestic method, thus conf...
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Briefs Surface Electrochemistry of Iron Porphyrins and Iron on Tin Oxide Electrodes 194 Iron porphyrins and Fe(III) chemisorb on SnC>2 electrodes and catalyze reduction of t h e electrode. D. G. Davis* and Royce W. Murray, Kenan Laboratories of Chemistry, University of North Carolina, Chapel Hill, N.C. 27514 Anal. Chem., 49 (1977) Digital Microcoulometric Measurements of Cadmium Anodic Stripping at the Micrometer Hanging Mercury Drop Electrode 199 T h e per-run loss of cadmium from t h e solution to t h e micrometer hanging mercury drop electrode is estimated by microcoulometry using readily available commercial instrumentation. E. D. Moorhead* and W. H. Doub, Jr., Department of Chemical Engineering, University of Kentucky, Lexington, Ky. 40506 Anal. Chem., 49 (1977) Thin-Layer Electrochemical Technique for Monitoring Electrogenerated Reactive Intermediates 206 Optical monitoring of reactive species combined with Nernstian control of reactant concentrations allows simplified examination of reaction kinetics. Richard L. McCreery, Department of Chemistry, Ohio State University, Columbus, Ohio 43210 Anal. Chem., 49 (1977) Activity Coefficients and Osmotic Coefficients in Aqueous Solutions of Choline Chloride at 25 "C 209 Activity coefficients of choline chloride obtained with a choline ion-selective electrode agree with those derived by the isopiestic method, thus confirming t h e Nernstian response of the choline electrode. J. B. Macaskill, M. S. Mohan, and Roger G. Bates,* Department of Chemistry, University of Florida, Gainesville, Fla. 32611 Anal. Chem., 49 (1977) Monoionic Liquid Membrane Potential in Non-Isothermal Systems 212 T h e thermal membrane potential dependence on both t h e counterion nature and activity and on t h e membrane solvent is studied with tetraheptylammonium organic solutions as monoionic liquid anion exchange membranes. Giancarlo Scibona, Mauro Magini, Bernardino Scuppa, Anna Castagnola, and Claudio Fabiani,* Material Division, C.N.E.N., CSN-Casaccia, Rome, Italy Anal. Chem., 49 (1977) Measurement of Complexation Properties of Humic and Fulvic Acids in Natural Waters with Lead and Copper Ion-Selective Electrodes 216 Values for mean molecular weight of the ligand, t h e stability constants of t h e complexes, number of ligands fixed per metal ion, and t h e dependency of t h e stability of the complexes on p H are obtained. Jacques Buffle,* France-Line Greter, and Werner Haerdi, Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 quai E. Ansermet, CH-1211 Genève 4, Switzerland Anal. Chem., 49 (1977)

Tris( pyrrolidine dithiocarbamato)cobalt(lll) Chelate Matrix for Trace Metal Preconcentration from Aqueous Solution by Coprecipitation 222 Concentration factors of 40 to 400 are available by this method in t h e preconcentration step prior to analytical determination by flame atomic absorption spectrophotometry. Kotra V. Krishnamurty and Michael M. Reddy,* Division of Laboratories and Research, New York State Department of Health, Albany, N.Y. 12201 Anal. Chem., 49 (1977) Chromatographic Measurement of Submicromolar Strong Compiexing Capacity in Phytoplankton Media 226 When an Echelle grating plasma emission spectrometer is used, t h e standard deviation of t h e technique is 2 X 10~ 8 M when measuring submicromolar compiexing capacity. Richard J. Stolzberg* and Diane Rosin, Harold Edgerton Research Laboratory, New England Aquarium, Central Wharf, Boston, Mass. 02110 Anal. Chem., 49 (1977) Design and Optimization of a Teflon Helix Continuous Liquid-Liquid Extraction Apparatus and Its Application for the Analysis of Organophosphate Pesticides in Water 231 Over 80% efficiency relative to batch extraction is demonstrated for ngA. concentrations of organophosphate pesticides from fortified waters. C. Wu and I. H. Suffet,* Environmental Studies Institute, Department of Chemistry, Drexel University, Philadelphia, Pa. 19104 Anal. Chem., 49 (1977) Determination and Characterization of Gallotannin by High Performance Liquid Chromatography 238 Assay and characterization is achieved by chromatographic separation and quantification of t h e various galloyl glucoses found in tannins. Weighted average molecular weight can be estimated from d a t a generated. Thomas H. Beasley, Sr., Howard W. Ziegler,* and Alexis D. Bell, Corporate Analytical Services Laboratory, Mallinckrodt, Inc., P.O. Box 5439, St. Louis, Mo. 63147 Anal. Chem., 49 (1977) Exclusion Chromatography in Dense Gases: An Approach to Viscosity Optimization 243 Fluids above t h e normal boiling point are proposed as solvents for exclusion chromatography capable of yielding reduced viscosity and therefore increased speed. J. Calvin Giddings,* Lyle M. Bowman, Jr., and Marcus N. Myers, Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 Anal. Chem., 49 (1977) Precision of Quantitative Electron Spin Resonance Using Copper(ll) Bound to Ion-Exchange Resins 250 Characterization and statistical evaluation of parameters affecting quantitative E S R measurements (precision of 4.3% for single concentration and 8% for thousand-fold concentration range) and new E S R sample handling techniques are reported. Doris C. Warren,* Department of Chemistry, Houston Baptist University, 7502 Fondren Rd., Houston, Texas 77074 and J . M. Fitzgerald, Department of Chemistry, University of Houston, Houston, Texas 77004 Anal. Chem., 49 (1977)

* Corresponding author. 102 A · ANALYTICAL CHEMISTRY, VOL. 49, NO. 2, FEBRUARY 1977

Briefs Determination of Mercury in Silver or Silver Nitrate by Atomic Absorption Spectrometry 255 T h e optimum conditions for t h e separation of mercury from silver as t h e HgBr4 2 ~ complex are studied. T h e relative standard deviation of t h e method is less t h a n 10%. W. W. White* and P. J . Murphy, Industrial Laboratory, Kodak Park Division, Eastman Kodak Company, Rochester, N.Y. 14650 Anal. Chem., 49 (1977)

Calculations of Isotopic Distribution in Molecules Extensively Labeled with Heavy Isotopes 281 Equations are presented which permit derivation of m a s s abundance relationships for molecules t h a t are extensively labeled with heavy isotopes. H. Yamamoto and James A. McCloskey,* Department of Biopharmaceutical Sciences, University of Utah, Salt Lake City, Utah 84112 Anal. Chem., 49 (1977)

Determination of Trace Metals in Fresh Water Mussels by Atomic Absorption Spectrometry with Direct Solid Sample Injection 257 Freeze-dried residues of fresh water mussels (exclusive of shell) are analyzed for Al, Cr, Cu, P b , and Zn by direct firing of solid samples in a graphite furnace atomizer. D. A. Lord, Environmental Protection Service—Canada, Halifax, N.S., Canada, and J. W. McLaren and R. C. Wheeler,* Department of Chemistry, Queen's University, Kingston, Ontario, Canada Anal. Chem., 49 (1977)

Qualitative and Quantitative Determination of Suspected Components in Mixtures by Target Transformation Factor Analysis of Their Mass Spectra 284 Target transformation factor analysis of mass spectral data is used to determine whether or not a suspected substance is present in a series of related mixtures, and to deduce t h e quantitative compositions as well. Edmund R. Malinowski* and Matthew McCue, Department of Chemistry and Chemical Engineering, Stevens Institute of Technology, Hoboken, N.J. 07030 Anal. Chem., 49 (1977)

Determination of Micromolar Quantities of Primary Amides by Flame Emission Spectrometry 262 T h e analysis of primary amides is accomplished by reaction with a modified Hofmann reagent t o produce BaCC>3 which is separated from t h e reaction mixture a n d determined by flame emission spectrometry. Raphael P. D'Alonzo and Sidney Siggia,* Department of Chemistry, University of Massachusetts, Amherst, Mass. 01002 Anal. Chem., 49 (1977)

Gas Chromatogi aphy-Mass Spectrometry Study of Acetylacetonyl Dipeptide Methyl Esters 287 G C / M S properties of Λί-acetylacetonyl dipeptide methyl esters are studied as a means t o provide unambiguous amino acid sequence data of enzymatically hydrolyzed po­ lypeptides. Hartmut Frank, K. D. Haegele, and D. M. Desiderio,* Institute for Lipid Research and Marrs McLean Department of Biochemis­ try, Baylor College of Medicine, Houston, Texas, 77025 Anal. Chem., 49 (1977)

Interelement Effects and a Possible Excitation Mechanism in a Low-Pressure Microwave Induced Helium Plasma 266 Solute-volatilization phenomena from t h e tantalum filam e n t are closely related t o matrix effects in t h e excitation of metals in a low-pressure microwave induced helium plasma. Hiroshi Kawaguchi, Ikuo Atsuya, and Bert L. Vallée,* Biophysics Research Laboratory, Department of Biological Chemistry, Harvard Medical School, and the Division of Medical Biology, Peter Bent Brigham Hospital, Boston, Mass. 02115 Anal. Chem., 49 (1977)

Colorimetric Hydroxylamine-lron(lll) Methods for Studies of the Enzymatic Hydrolyses of Cyclic Imides and of Amic Acids 292 T h e methods are developed for studies of t h e enzymatic and non-enzymatic hydrolysis of a cyclic imide to its ringopened product, an amic acid, and of an amic acid to its dicarboxylic acid derivative. James H. Maguire and Kenneth H. Dudley,* Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, N.C. 27514 Anal. Chem., 49 (1977)

Determination of Impurities in Gases by Atmospheric Pressure Ionization Mass Spectrometry 270 T h e technique is successfully applied to detection of small inorganic molecules in highly purified gases. A collision induced decomposition method is employed to distinguish cluster ions from other stable ions. Hideki Kambara* and Ichiro Kanomata, Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, Japan Anal. Chem., 49 (1977)

Multivariate Statistical Approach to the Fingerprinting of Oils by Infrared Spectrometry 297 T h e requirements of normality and independence are ex­ amined, a n d two methods of baseline placement are consid­ ered. James S. Mattson,* Carol S. Mattson, Mary J o Spencer, and Scott A. Starks, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Fla. 33149 Anal. Chem., 49 (1977)

Numerical Analysis of Multicomponent Spectra 276 T h e applications of nonnegative linear least squares a n d simplex algorithms are discussed. Their applications t o spectrophotometric d a t a in t h e computation of either molar absorptivities or concentrations are illustrated. D. J . Leggett, University of Waterloo, Waterloo, Ontario, Canada Anal. Chem., 49 (1977)

Radiochemical Determination of Lead-210 in Uranium Ores and Air Dusts 302 Filter papers and siliceous samples are dissolved complete­ ly by wet ashing to avoid loss of lead by volatilization or re­ duction. Bismuth-210 is precipitated with barium sulfate for beta counting. Claude W. Sill* and Conrad P. Willis, Health Services Laborato­ ry, U.S. Energy Research and Development Administration, Idaho Falls, Idaho 83401 Anal. Chem., 49 (1977)

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Briefs High Precision Pulse Counting: Limitations and Optimal Conditions 306 T h e interaction between overall precision, deadtime uncertainty, and count rate is used to determine optimal and maximal count rates. J. M. Hayes* and D. A. Schoeller, Departments of Chemistry and Geology, Indiana University, Bloomington, Ind. 47401 Anal. Chem., 49 (1977) Enrichment of Trace Metals in Water by Adsorption on Activated Carbon 311 Chelation and subsequent adsorption on activated carbon allows quantitative enrichment for over 20 trace metals from aqueous solutions, with a 5-10% precision, without any significant influence of a b u n d a n t alkali or alkaline earth ions. Bruno M. Vanderborght and Rene E. Van Grieken,* Department of Chemistry, University of Antwerp (U.I.A.), B-2610 Wilrijk, Belgium Anal. Chem., 49 (1977) Residue Analysis of Sediment and Sewage Sludge for Organochlorines in the Presence of Elemental Sulfur 316 T h e recovery of added organochlorines is above 80% and the detection limit in t h e range of 1-10 p p b from a 10-g sample. Sôren Jensen,* Lars Renberg, and Lars Reutergardh, National Swedish Environment Protection Board, Special Analytical Laboratory, Wallenberg Laboratory Lilla Frescati, S-104 05 Stockholm, Sweden Anal. Chem., 49 (1977) Kinetics of Oxalate Attack on Ferrozine-lron(ll) Complex and Regeneration of Ligand in Determination of Iron(ll) 319 T h e rate law a n d rate constants (over a range of oxalate and complex ion concentrations) are determined a t 45-70 °C. V. V. S. Eswara Dutt and Horacio A. Mottola,* Chemistry Department, Oklahoma State University, Stillwater, Okla. 74074 Anal. Chem., 49 (1977) Determination of Hydrogen Cyanide in Combustion Gases by a Four-Channel Continuous Analyzer 322 T h e analyzer measures t h e red color formed by heating cyanide with sodium picrate. Concentrations from 0 t o 200 p p m by volume can be measured. Desmond Alan Reilly, Imperial Chemical Industries Limited, Organics Division, Hexagon House, Blackley, Manchester M93 DA, England Anal. Chem., 49 (1977) Chlorine-Selective Detection for Liquid Chromatography with a Coulson Electrolytic Conductivity Detector 326 A commercial gas chromatographic detector is adapted t o monitoring effluent from a reversed-phase liquid chromatographic column. Cl-containing pesticides are detectable at sub-microgram levels. John W. Dolan and James N. Seiber,* Department of Environmental Toxicology, University of California, Davis, Calif. 95616 Anal. Chem. 49 (1977)

Analysis of Cigarette Smoke by Fourier Transform Infrared Spectrometry 331 Several gas phase components are determined simultaneously by FT-IR in whole fresh cigarette smoke under conditions simulating animal exposure experiments. Precision of determinations ranged from 34 to 3%. Wayne L. Maddox,* Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tenn. 37830, and Gleb Mamantov, Department of Chemistry, University of Tennessee, Knoxville, Tenn. 37916 Anal. Chem., 49 (1977)

Correspondence Determination of Mercury by Atomic Absorption Spectrometry with Graphite Tube Atomization 336 J. F. Alder* and David A. Hickman, Department of Chemistry, Imperial College of Science & Technology, London, SW7 2AY, England Anal. Chem., 49 (1977) Exchange of Comments: Signal Flicker Noise and Noise Power Spectra 339 J. D. Ingle, Jr.,* Department of Chemistry, Oregon State University, Corvallis, Ore. 97331, and Yair Talmi,* Princeton Applied Research Corp., P.O. Box 2565, Princeton, N.J. 08540, and Ronald Crosmun, E. I. du Pont de Nemours & Co., Inc., Wilmington, Del. 19898 Anal. Chem., 49 (1977)

Aids for Analytical Chemists 1024-Point Transient Recorder 342 K. R. Betty and Gary Horlick,* Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2E1 Anal. Chem., 49 (1977) QUAN—A Computer Program for Quantitative X-ray Fluorescence Analysis 345 Michael F. Ciccarelli, General Electric Company, Corporate Research & Development, Schenectady, N.Y. 12305 Anal. Chem., 49 (1977) Sampling of Metal Air Particulates for Analysis by Furnace Atomic Absorption Spectrometry 346 B. N. Noller* and Harry Bloom, Chemistry Department, University of Tasmania, Box 252C, G.P.O., Hobart 7001, Australia Anal. Chem., 49 (1977) Vertical Furnace-Type Sampling Device for Pyrolysis Gas Chromatography 348 Shin Tsuge,* and Tsugio Takeuchi, Department of Synthetic Chemistry, Nagoya University, Nagoya 464, Japan Anal. Chem., 49 (1977) Frequency Response Plots for Savitzky-Golay Filter Functions 351 K. R. Betty and Gary Horlick,* Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2E1 Anal. Chem., 49 (1977) Correction. Transducer for Measurement of Flow Rates In StoppedFlow Mixing Systems 352 F. J. Holler, S. R. Crouch, and C. G. Enke

106 A · ANALYTICAL CHEMISTRY, VOL. 49, NO. 2, FEBRUARY 1977