BRIEFS
Visman Equations in the Design of Sampling Plans for Chemical Analysis of Segregated Bulk Materials 226 Guidelines are presented for determining whether a bulk population is well mixed or segregated. An average theoreti cal particle mass of 20 g is calculated for unmixed samples of Athabasca oil sand. Dean Wallace*, Oil Sands Research Department, Alberta Research Council, Edmonton, Alberta, Canada T6H 5X2, and Byron Kratochvil, Department of Chemistry, University of Alberta, Edmon ton, Alberta, Canada T6G 2G2 Anal. Chew.., 59 (1987) Simultaneous Extraction of Trivalent and Pentavalent Antimony and Arsenic Species in Natural Waters for Neutron Activation Analysis 233 The pyrrolidinecarbodithioate extraction method combined with NAA is capable of determining As(III), As(V), Sb(III), and Sb(V) species in natural waters at 10~3 μg/L. W. M. Mok and C. M. Wai*, Department of Chemistry, University of Idaho, Moscow, Idaho 83843 Anal. Chem., 59 (1987) Selective Detection of Classes of Chemical Compounds by Gas Chromatography/Mass Spectrometry/Pattern Recognition: Polycyclic Aromatic Hydrocarbons and Alkanes 236 Classification of mass spectra is based on the generation of numerical features derived from spectral data. Parameters of linear binary classifiers are computed by multivariate regression. Hans Lohninger and Kurt Varmuza*, Institute for General Chemistry, Technical University Vienna, Lehargasse 4/152, A-1060 Vienna, Austria Anal. Chem., 59 (1987) Coulostatic Electrochemical Detection in Flow Injection Analysis 244 A theory relating peak area to flow cell geometry and flow rate is developed. The detection limit for o-aminophenol is 5 pmol injected. The feasibility of detection in highly resistive mobile phases is investigated. Susan R. Mikkelsen and William C. Purdy*, Department of Chemistry, McGill University, 801 Sherbrooke Street West, Mon treal, Canada H3A 2K6 Anal. Chem., 59 (1987) Simultaneous Electrochemical Determination of Diffusion and Partition Coefficients of Potassium Ferrocyanide for Albumin-Glutaraldehyde Membranes 248
Electrochemical and Ultraviolet-Visible Spectroelectrochemical Investigation of Selectivity of Potentiometric Gas Sensors Based on Polypyrrole 253 Selectivity of suspended gate field effect transistors, with respect to aromatic compounds, acetonitrile, alcohols, and water, can be modified by electrochemical incorporation of different compounds into the polypyrrole layer within the transistor structure. Mira Josowicz and Jiri Janata*, Center for Sensor Technology, University of Utah, Salt Lake City, Utah 84112, and Kevin Ashley and Stanley Pons, Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 Anal. Chem., 59 (1987) Hydrogen Ion Selective Microelectrode Prepared by Modifying an Electrode with Polymers 258 The pH sensor does not contain an inner standard solution layer between the electrode substrate and the film. The sensor has characteristics similar to those reported for con ventional pH glass membrane electrodes. Noboru Oyama* and Tomoaki Hirokawa, Department of Ap plied Chemistry for Resources, Tokyo University of Agriculture & Technology, Koganei, Tokyo 184, Japan, and Shuichiro Yamaguchi, Norihiko Ushizawa, and Takeshi Shimomura, Technical R & D Division, Terumo Corporation, Hatagaya, Shibuya-ku, To kyo 151, Japan Anal. Chem., 59 (1987) Computer-Assisted Rapid-Scan Cyclic Staircase Voltammetry in Normal-Phase High-Performance Liquid Chromatography 262 The technique is tested on oxy and nitro derivatives of poly cyclic aromatic hydrocarbons, catecholamines, and oestro gen steroids. Both reductive and oxidative ranges are inves tigated. Hari Gunasingham*, B. T. Tay, and K. P. Ang, Department of Chemistry, National University of Singapore, Kent Ridge, Singa pore 0511 Anal. Chem., 59 (1987) Determination of Ivermectin by Fluorescence Derivatization 266 Both the oxidation of 22,23-dihydroavermectin B l a (H 2 Bi a ) to the corresponding 5-ketone by Mn02 and its subsequent conversion to the fluorescent derivative are reproducible and linear over the parent avermectin concentration range of 0.01-10 Mg/mL. John D. Stong, Merck Sharp and Dohme Research Laboratories, P.O. Box 2000, Rahway, N.J. 07065 Anal. Chem., 59 (1987)
Potential step chronoamperometry followed by steady-state diffusion-limited current measurements with a rotating-disc platinum electrode is used. The coefficients are influenced by the pH of the electrolyte. Carl A. Marrese, Osato Miyawaki, and Lemuel B. Wingard, Jr.*, Department of Pharmacology, School of Medicine, University of Pittsburgh, Pittsburgh, Pa. 15261 Anal. Chem., 59 (1987)
* Corresponding author • Supplementary material 68 A · ANALYTICAL CHEMISTRY, VOL. 59, NO. 2, JANUARY 15, 1987
BRIEFS Resolution of Multicomponent Fluorescence Emission by Phase Sensitive Detection at Multiple Modulation Frequencies 271
Determination of Sulfur Dioxide by Pulsed Ultraviolet Laser Photoacoustic Spectroscopy 300
The data are used to resolve the lifetimes and steady-state spectra of two-component mixtures without independent knowledge of the parameters. Susan M. Keating-Nakamoto, Henryk Cherek, and Joseph R. Lakowicz*, School of Medicine, University of Maryland at Balti more, 660 West Redwood Street, Baltimore, Md. 21201 Anal. Chem., 59 (1987)
A limiting sensitivity of 0.2 ppbv (S/N—1) for SO2 in purified air is achieved, which corresponds to an absorption coeffi cient of 2.9 X 10^9 cm" 1 . P. Vujkovic Cvijin, D. A. Gilmore, M. A. Leugers, and G. H. Atkinson*, Department of Chemistry and Optical Sciences Center, University of Arizona, Tucson, Ariz. 85721 Anal. Chem., 59 (1987)
Luminescence Ratio Indicators for Oxygen
Sampling and Excitation of Refractory Solids with a Theta Pinch Discharge Designed as an Atomic Emission Source
279
The indicators have separate oxygen-sensitive and oxygeninsensitive emission bands and are suitable for measuring gas-phase oxygen partial pressures. Eric D. Lee, Allied Health and Scientific Products, 1 Burtt Road, Andover, Mass. 01810, and T. C. Werner*, Department of Chemis try, Union College, Schenectady, N.Y. 12308, and W. Rudolf Seitz*, Department of Chemistry, University of New Hampshire, Durham, N.H. 03824 Anal. Chem., 59 (1987) Rapid Rate Measurements by the Pulsed-Accelerated-Flow Method 283 B 1
First-order rate constants as large as 124,000 s" (ii/ 2 = 5.6 μβ) and second-order rate constants as large as 2 X 109 M _ 1 s _1 are measured. A twin-path mixing-observation cell is characterized. Mark T. Nemeth, Kimber D. Fogelman, Thomas Y. Ridley, and Dale W. Margerum*, Department of Chemistry, Purdue Universi ty, West Lafayette, Ind. 47907 Anal. Chem., 59 (1987) Selective Concentration of Cobalt in Seawater by Complexation with Various Ligands and Sorption on Macroporous Resins The selective concentration of trace amounts of cobalt is examined using 14 ligands and 2 XAD resins. Complexed cobalt is collected after passage through a small XAD resinpacked column. Kenji Isshiki, Department of Chemistry, Faculty of Science, Kyoto University, Kyoto 606, Japan, and Eiichiro Nakayama*, Instru mental Analytical Research Center, Faculty of Science, Kyoto Uni versity, Kyoto 606, Japan Anal. Chem., 59 (1987) Optimization of a Flow Cell Interface for Reversed-Phase Liquid Chromatography/Fourier Transform Infrared Spectrometry An interface device based on the postcolumn extraction of solutes into a proper analyte fluid is constructed. The device allows for the detection of solutes within the time frame of the chromatographic separation. John W. Hellgeth and Larry T. Taylor*, Department of Chemis try, Virginia Polytechnic Institute and State University, Blacksburg, Va. 24061 Anal. Chem., 59 (1987)
305
The capabilities of a theta pinch source to sample and excite refractory solids, both conductors and nonconductors, are discussed. Analyte emission intensities are increased by spa tial positioning of the sample within the discharge vessel. Jeffrey S. White and Alexander Scheeline*, School of Chemical Sciences, University of Illinois, 1209 West California Street, 79 RAL, Box 48, Urbana, 111. 61801 Anal. Chem., 59 (1987) Evaluation of a Voigt Effect Coherent Forward Scattering Atomic Spectrometer
309
A continuum source is used to excite simultaneously all atomic transitions. An air-acetylene flame and a graphite furnace are used as atom reservoirs. L. A. Davis and J. D. Winefordner*, Department of Chemistry, University of Florida, Gainesville, Fla. 32611 Anal. Chem., 59 (1987) Cesium Ion Desorption Ionization with Fourier Transform Mass Spectrometry 313 Nonvolatile organic molecules of molecular weights up to 2000-3000 are analyzed. A detection limit of 10" 13 mol is demonstrated for the peptide gramicidin S. I. Jonathan Amster, Joseph A. Loo, Jorge J. P. Furlong, and Fred W. McLafferty*, Chemistry Department, Cornell University, Ithaca, N.Y. 14853-1301 Anal. Chem., 59 (1987) Self-Modeling Curve Resolution by Factor Analysis of a Continuous Series of Pyrolysis Mass Spectra
317
The method uses factor analysis combined with the variance diagram technique to resolve the total ion current curves from time-resolved pyrolysis MS data into the chemical component curves and their spectra. Willem Windig*, Emma Jakab, Joseph M. Richards, and Henk L. C. Meuzelaar, Biomaterials Profiling Center, University of Utah, Salt Lake City, Utah 84108 Anal. Chem., 59 (1987)
70 A · ANALYTICAL CHEMISTRY, VOL. 59, NO. 2, JANUARY 15, 1987
BRIEFS Liquid Chromatographic Assay of ^-Lactamase Inhibitors in Human Serum and Urine Using a Hollow-Fiber Postcolumn Reactor 324
Computerized Library Search Routine for Comparing Ultraviolet Spectra of Drugs Separated by High-Performance Liquid Chromatography 350
Clavulanic acid and sulbactam are determined in serum and urine. The limit of detection is 25 ng/mL in serum and 50 ng/ mL for a 10-fold dilution of urine. Jun Haginaka*, Junko Wakai, and Hiroyuki Yasuda, Faculty of Pharmaceutical Sciences, Mukogawa Women's University, 4-16 Edagawa-cho, Nishinomiya, Hyogo 663, Japan Anal. Chem., 59 (1987)
Reference compounds are separated on an acidic and/or basic HPLC solvent gradient system. A reference library containing the UV spectra of more than 300 drugs is established for comparison with unknown drug samples. Dennis W. Hill*, Thomas R. Kelley, and Karen J. Langner, College of Agriculture and Natural Resources, Microchemistry Laboratory U-193, Storrs, Conn. 06268 Anal. Chem., 59 (1987)
Ultrasonic Micronebulizer Interface for High-Performance Liquid Chromatography with Flame Photometric Detection
Determination of Surface Polarity by Heterogeneous Gas-Solid Chromatography 353
Dual-wavelength operation can improve the signal-to-noise ratio by a factor of 5, improve the precision from 6% to 2%, and eliminate baseline shifts. The micronebulizer FPD is demonstrated for the determination of phospholipids and sugar phosphates. J. F. Karnicky* and L. T. Zitelli, Varian Research Center, 611 Hansen Way, Palo Alto, Calif. 94303, and Sj. van der Wal*, Varian Instrument Group, 2700 Mitchell Drive, Walnut Creek, Calif. 94598 Chlorine-Selective Detector for Microcolumn Liquid Chromatography
334
A linear response between 5 and 70 ng for 1,1,2-trichloroethane in 15% methanol/water is observed. With a thermospray interface, 80-90% of the chlorine content is converted to yield element-specific detection. Staffan Folestad*, Bjorn Josefsson, and Peter Marstorp, Department of Analytical and Marine Chemistry, Chalmers University of Technology, University of Goteborg, S-412 96, Gôteborg, Sweden Anal. Chem., 59 (1987) High-Efficiency Microcolumn Liquid Chromatography Separation and Spectral Characterization of NitrogenContaining Polycyclics from Fossil Fuels
339 B
High chromatographic efficiencies (~200,000 theoretical plates) are needed to separate the complex mixtures. Most of the structural data is obtained by MS; information on the shape of the molecules is derived from fluorescence emission spectra. Claudio Borra, Donald Wiesler, and Milos Novotny*, Department of Chemistry, Indiana University, Bloomington, Ind. 47405 Anal. Chem., 59 (1987) Continuous Particle Fractionation Based on Gravitational Sedimentation in Split-Flow Thin Cells
344
The resolution and other separation parameters are adjusted by creating and controlling a special crossover flow. Appropriate expressions governing the operational characteristics of the method are developed and correlate well with experimental results. Stephen R. Springston, Marcus N. Myers, and J. Calvin Giddings*, Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 Anal. Chem., 59 (1987)
Monolayer adsorption energies calculated from chromatographic retention data are used to construct a surface polarity scale that is similar to the Rohrschneider scale used to characterize liquid phases in GLC. Scott P. Boudreau and William T. Cooper*, Department of Chemistry, Florida State University, Tallahassee, Fla. 32306-3006 Anal. Chem., 59 (1987) N-Substituted Aminoalkylsulfonates as Eluents in MembraneSuppressed Anion Chromatography 358 Fifteen nitrogen-substituted aminoalkylsulfonates are evaluated for suppressibility and chromatographic properties. A wide range in eluent strength and low residual conductivities is observed. Knut Irgum, Department of Analytical Chemistry, University of Umeà, S-901 87 Umeâ, Sweden Anal. Chem., 59 (1987) Gradient Membrane-Suppressed Anion Chromatography with N-Substituted Aminoalkylsulfonic Acid Salts as Eluents 363 Gradients of sodium 2-aminoethanesulfonate, sodium hydroxide, and sodium 3-(iV-cyclohexylamino)-l-propanesulfonate are used as eluents for separating eight mono- and divalent anions. Knut Irgum, Department of Analytical Chemistry, University of Umeà, S-901 87 Umeâ, Sweden Anal. Chem., 59 (1987)
Correspondence Frequency Response of Initial Point Least Squares Polynomial Filters 367 Peter D. Wentzell, Thomas P. Doherty, and S. R. Crouch*, Department of Chemistry, Michigan State University, East Lansing, Mich. 48824 Anal. Chem., 59 (1987) Polymer Investigations with the Laser Microprobe 371 Reimer Holm*, Bayer AG, Central Research and Development, D-5090 Leverkusen, Federal Republic of Germany, and Michael Karas, University of Frankfurt, Institute of Biophysics, D-6000 Frankfurt, Federal Republic of Germany, and Henning Vogt, Leybold-Heraeus GmbH, D-5000 Kôln, Federal Republic of Germany Anal. Chem., 59 (1987)
72 A · ANALYTICAL CHEMISTRY, VOL. 59, NO. 2, JANUARY 15, 1987
GAS FACTS
Aids for Analytical Chemists
published periodically were observed to have activfor analytical chemists ity. In an anhydrous system
Determination of Vanillylmandelic Acid in Urine by Use of Catalytic Maximum Wave in Differential Pulse Polarography 373
the reaction was found to be significantly affected by 0-5 ppmv oxygen. For example, such traces of oxygen accelerated the FeO-catalyzed For many years it's been conversion of CO from 1.80 suspected that low concentra- to 13.09%/year. Interesttions (20 ppmv) of carbon ingly, an increase in oxygen monoxide reacted unpredict- concentration in the FeO ably with steel cylinder sursystem to 30 ppmv then faces. Measurements carried decreased the reaction rate out at Scott have shown to a loss of 2.97%/year. that the reaction proceeds It was hypothesized that at at room temperature. It was the higher concentration.
CO interaction with metal surfaces
BRIEFS
Kiyoshi Hasebe*, Teiji Kakizaki, and Hitoshi Yoshida, Department of Chemistry', Faculty of Science, Hokkaido University, Sapporo 060, Japan Anal. Chem., 59 (1987)
Open-Tubular Mixer for Gradient Preparation in Microbore High-Performance Liquid Chromatography 376 Karel Slais and Roland W. Frei*, Department of Analytical Chemistry, Free University, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands Anal. Chem., 59 (1987)
Determination of Trace Levels of Trimethylamine in Air by Gas Chromatography/Surface Ionization Organic Mass Spectrometry 379 Toshihiro Fujii* and Toshihumi Kitai, National Institute for Environmental Studies, Tsukuba, Ibaraki 305, Japan Anal. Chem., 59 (1987)
Controlled Back Pressure Valve for Constant Flow and Pressure Programming in Packed Column Supercritical Fluid Chromatography 382 K. R. Jahn and B. W. Wenclawiak*, Anorganisch Chemisches Institut, Westfâlische Wilhelmsuniversitàt, Corrensstrasse 36, D-4400 Mimster, FRG Anal. Chem., 59 (1987)
Loss of CO in untreated steel cylinders. Linear least squares fit.
found too that the rate varies significantly from cylinder to cylinder. Batches of 20 cylinders showed concentration losses ranging from < 1 % to >5%/year. Mean concentration change was -1.07%/year. Good agreement was found between CO loss and C02 formation. Eg, loss of CO of 0.188 ppmv/year was offset by COz formation of 0.200 ppmv/year. The reaction was determined to involve various metal oxides on the inner surface of the cylinders. All the iron oxides
oxygen competed for active sites on the metal oxide surface, hindering adsorption of CO. When water was introduced into the system, FeO activity was reduced so CO loss was only 0.09%/year. Scott has developed unique cylinder wall treatments to reduce CO losses to
