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tive chromatographic peak shapes are examined. The rela- tive utilities of threemeasurements of preparative chro- matographic peak width are tested. ...
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Perspective: Analytical Biotechnology

Structural Analysis of Polychlorinated Biphenyls from Carbon-13 Nuclear Magnetic Resonance Spectra

Carbohydrate Characterization of Recombinant Glycoproteins of Pharmaceutical Interest 1714 Carbohydrate characterization of recombinant glycoproteins entails the determination of the primary structures and points of attachment of the oligosaccharide moieties. Several methods for oligosaccharide- and glycosylation-site characterization are reviewed. Michael W. Spellman, Department of Medicinal and Analytical Chemistry, Genentech, Inc., South San Francisco, CA 94080

Articles Effects of Extracolumn Convolution on Preparative Chromatographic Peak Shapes

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The effects of injector and detector convolution on preparative chromatographic peak shapes are examined. The relative utilities of three measurements of preparative chromatographic peak width are tested. Eric V. Dose and Georges Guiochon*, Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, and Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 Infrared Laser Desorption Mass Spectrometry of Oligosaccharides: Fragmentation Mechanisms and Isomer Analysis 1731 The two-bond ring cleavages observed in the IR laser desorption mass spectra of oligosaccharides are interpreted as a series of retro-aldol reactions occurring prior to cation attachment. Bernhard Spengler, Joseph W. Dolce, and Robert J. Cotter*, Department of Pharmacology and Molecular Sciences, Middle Atlantic Mass Spectrometry Facility, The Johns Hopkins University School of Medicine, Baltimore, MD 21205 Determination of Complexing Ability of Natural Ligands in Seawater for Various Metal Ions Using Ion Selective Electrodes 1737 Organic ligands isolated from seawater are electrodialyzed with EDTA to remove metals, and their ability to form complexes with Cu(II) and Cd(II) is discussed. Takashi Midorikawa*, Eiichiro Tanoue, and Yukio Sugimura, Geochemical Laboratory, Meteorological Research Institute, Nagamine 1-1, Tsukuba, Ibaraki 305, Japan

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Predictive model equations are used to simulate C NMR spectra for nine conformations of each compound. The conformation that produces the most accurate simulated spectrum is used to develop new equations for further simulations, allowing conformations to be successively adjusted. Debra S. Egolf and Peter C. Jurs*, Department of Chemistry, 152 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 Unintensified Photodiode Array Fluorescence Detector for HighPerformance Liquid Chromatography 1754 The detector, an unintensified diode array, uses a low-wattage xenon capillary flashlamp as an excitation source. Jeff Wegrzyn, Gabor Patonay, Michael Ford, and Isiah Warner*, Department of Chemistry, Emory University, Atlanta, GA 30322 Optical Detection of Cationic Surfactants Based on Ion Pairing with an Environment-Sensitive Fluorophor 1758 Fluorescence from the immobilized indicator intensifies and shifts to shorter wavelengths with increasing cationic surfactant concentration. Ziad M. Shakhsher and W. Rudolf Seitz*, Department of Chemistry, University of New Hampshire, Durham, NH 03824 Selective Detection of lodinated Hydrocarbons by the Electron Capture Detector with Negative Ion Hydration and Photodetachment 1762 The GC detector responds to organic iodides and not to organic chlorides. The detection limit for CH 3 I in air is 0.01 ppb. R. E. Arbon and E. P. Grimsrud*, Department of Chemistry, Montana State University, Bozeman, MT 59717 Design of Optimized Finite Impulse Response Digital Filters for Use with Passive Fourier Transform Infrared Interferograms 1768 Methods are described for designing narrow bandpass digital filters that can be used in the real-time analysis of passive Fourier transform IR data collected in remote-sensing applications. By employing a procedure based on regression analysis, one can obtain filters that offer excellent performance and require relatively few computations to implement. Gary W. Small* and Amy C. Harms, Department of Chemistry, The University of Iowa, Iowa City, IA 52242 and Robert T. Kroutil, John T. Ditillo, and William R. Loerop, U.S. Army Chemical Research, Development, and Engineering Center, Aberdeen Proving Ground, MD 21010

* Corresponding author 872 A · ANALYTICAL CHEMISTRY, VOL. 62, NO. 17, SEPTEMBER 1, 1990

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Determination of Microstructure and Composition in Butadiene and Styrme-Butadiene Polymers by Near-Infrared Spectroscopy 1778 The multivariate method of classical least squares is used to analyze the near-IR spectra of polymers in bulk samples and in carbon tetrachloride solutions and to determine the concentrations of all structural units. Charles E. Miller*, B. E. Eichinger, Thomas W. Gurley, and James G. Hermiller, Center for Process Analytical Chemistry, Department of Chemistry, BG-10, University of Washington, Seattle, WA 98195 and Analytical Science Department, Goodyear Tire and Rubber Company, 142 Goodyear Boulevard, Akron, OH 44305 Optimization of High-Sensitivity Fluorescence Detection

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General expressions are presented for the number of photons emitted by a fluorescent chromophore as a function of the intensity and duration of illumination. Richard A. Mathies* and Konan Peck, Chemistry Department, University of California, Berkeley, CA 94720 and Lubert Stryer, Department of Cell Biology, Stanford University School of Medicine, Stanford, CA 94305 Spectroscopic Calibration and Quantitation Using Artificial Neural Networks 1791 Artificial neural networks are applied for nonlinear multivariate spectroscopic calibration by using near-IR and U V vis data. When a nonlinear spectral response is present, artificial neural networks provide better predictive performance than principal component regression. James R. Long, Vasilis G. Gregoriou, and Paul J. Gemperline*, Department of Chemistry, East Carolina University, Greenville, NC 27858

Systematic Delineation of Scan Modes in Multidimensional Mass Spectrometry 1809 A complete set of MS/MS/MS experiments is delineated, and applications of several ID and 2D experiments are provided. Jae C. Schwartz, Adrian P. Wade, Christie G. Enke, and R. Graham Cooks*, The Chemistry Department, Purdue University, West Lafayette, IN 47907-3699, The Chemistry Department, Michigan State University, East Lansing, MI 48824, and British Petroleum Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN, United Kingdom Long-Term Performance of a Gas Chromatography/Tandem Mass Spectrometry Assay for Tebufelone in Plasma 1819 An automated GC/MS/MS-based method is applied to the quantitation of 0.5-30 000 ppb tebufelone in plasma. Analytical figures of merit (monitored over two years) consistently meet or exceed those determined at initial validation. Roy L.M. Dobson*, David M. Neal, Bruce R. DeMark, and Susan R. Ward, Health & Personal Care Technology Division, Miami Valley Laboratories, The Procter & Gamble Company, P.O. Box 398707, Cincinnati, OH 45239-8707 Dynamical Behavior of Ions in a Radio Frequency Spark Ion Source 1825 Time-dependent potential distribution and dynamical behavior of the ion trajectories in a radio frequency spark ion source are calculated. Phase-angle dependence of the transmission and mass discrimination effects are demonstrated for the first time. Mark van Straaten*, Akos Vertes, and Renaat Gijbels, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium

On-Line Monitoring of Bioreactions of Bacillus polymyxa and Klebsiella oxytoca by Membrane Introduction Tandem Mass Spectrometry with Flow Injection Analysis Sampling 1798

Screening Strategy for the Detection of Derivatized Glutathione Conjugates by Tandem Mass Spectrometry 1827

MIMS-FIA provides continual on-line quantitation of the liquid-phase products of fermentation. Results are comparable to those obtained with off-line GC. Mark J. Hayward, Tapio Kotiaho, Anita K. Lister, R. Graham Cooks, Glen D. Austin, Ramani Narayan, and George T. Tsao*, Department of Chemistry and Laboratory of Renewable Resources Engineering, Purdue University, West Lafayette, IN 47907

Glutathione conjugates are isolated from biological matrices as iV-[(benzoyloxy)carbonyl] dimethyl ester derivatives and detected by constant neutral loss scanning for the elimination of glycine methyl ester. Paul G. Pearson, William N. Howald, and Sidney D. Nelson*, Department of Medicinal Chemistry, BG-20, School of Pharmacy, University of Washington, Seattle, WA 98195

Variations in Detection Efficiency of Halobenzenes Studied by Using Gas Chromatography/Laser Ionization Mass Spectrometry: Correlation with Excited-State Lifetimes 1804

High-Accuracy Molecular Mass Determination of Proteins Using Matrix-Assisted Laser Desorption Mass Spectrometry 1836

Four halogenated benzenes are studied by laser ionization GC/MS. Si excited-state lifetimes are also measured. The variation of the observed lifetimes explains the results. Charles W. Wilkerson, Jr., and James P. Reilly*, Department of Chemistry, Indiana University, Bloomington, IN 47405

The mass accuracy of matrix-assisted laser desorption TOFMS is ~ ± 0.01% for proteins with resolved protonated molecule ion signals and a sample consumption of 1 pmol. Ronald C. Beavis* and Brian T. Chait, The Rockefeller University, New York, NY 10021

874 A · ANALYTICAL CHEMISTRY, VOL. 62, NO. 17, SEPTEMBER 1, 1990

BRIEFS Streptavidin-Based Macromolecular Complex Labeled with a Europium Chelator Suitable for Time-Resolved Fluorescence Immunoassay Applications 1841 A fluorescent streptavidin-based macromolecular complex can be used as a universal detection system in time-resolved fluorescence immunoassays. Improvements (8- to 26-fold) in detection limits, when compared with the reagent, SA-TG(BCPDA) 150 , are achieved. Robert C. Morton, CyberFluor Inc., 179 John Street, Toronto, Ontario M5T1X4, Canada and Eleftherios P. Diamandis*, CyberFluor Inc., 179 John Street, Toronto, Ontario M5T 1X4, Canada, and Department of Clinical Biochemistry, University of Toronto, 100 College Street, Toronto, Ontario M5G 1L5, Canada Fourier Analysis of Multicomponent Chromatograms. Theory and Models 1846 A method of representing statistical properties of multicomponent chromatograms is presented. Detailed expressions of the power spectrum as a function of the number of single component peaks, peak shape, retention time distribution, and peak height dispersion ratio are discussed. Attila Felinger, Department of Analytical Chemistry, University of Chemical Engineering, P.O. Box 158, H-8201 Veszprém, Hungary and Luisa Pasti and Francesco Dondi*, Department of Chemistry, University of Ferrara, 1-44100 Ferrara, Italy Fourier Analysis of Multicomponent Chromatograms. Numerical Evaluation of Statistical Parameters 1854 A method for the simultaneous evaluation of the number of components and peak shape parameters in a multicomponent Poisson-type chromatogram is presented. The method, based on the power spectrum computation, is checked by simulation under a wide variety of chromatogram attributes. Attila Felinger, Department of Analytical Chemistry, University of Chemical Engineering, P.O. Box 158, H-8201 Veszprém, Hungary and Luisa Pasti, Pierluigi Reschiglian, and Francesco Dondi*, Department of Chemistry, University of Ferrara, 1-44100 Ferrara, Italy Variable Flow Rates and a Sinusoidal Flow Pump for Flow Injection Analysis 1861 The principles behind the use of sinusoidal flow in various flow-programming strategies for FIA analysis are discussed with reference to the random walk model. The feasibility of these principles is demonstrated by using a prototype sinusoidal flow pump. Jaromir Ruzicka*, Graham D. Marshall, and Gary D. Christian, Department of Chemistry, BG-10, University of Washington, Seattle, WA 98195 Simultaneous Dual-Column, Dual-Detector Gas Chromatographic Determination of Chlorinated Pesticides and Polychlorinated Biphenyls in Environmental Samples 1867

Capillary Electrophoresis in 2 and 5 μηι Diameter Capillaries: Application to Cytoplasmic Analysis 1872 Capillary electrophoresis with electrochemical detection is performed in 2- and δ-μτα capillaries. Solutes in single nerve cell cytoplasm are acquired, separated, and detected. Teresa M. Olefirowicz and Andrew G. Ewing*, Department of Chemistry, 152 Davey Laboratory, Penn State University, Universi­ ty Park, PA 16802 Gas Chromatographic Determination of Acetonitrile in Air Using a Thermionic Detector 1876 The method involves collection of air in 2 dm 3 glass or stain­ less steel vessels and preconcentration of acetonitrile by cryogenic trapping. The detection limit (defined as the blank value plus 3 times the standard deviation) is 15 pg for ~ 0.5 dm 3 of air sample. Stephan Hamm and Peter Warneck*, Max-Planck-Institut fur Chemie (Otto-Hahn-Institut), 6500 Mainz, Federal Republic of Germany Simulation of Carbon-13 Nuclear Magnetic Resonance Spectra of Alkyl-Substituted Aromatic Compounds 1884 Several structural parameters are developed and used to simulate the 13C NMR chemical shifts of a large group of alkyl-substituted aromatic compounds. Alternative means of treating aromatic ring carbons along with the simulation of subspectra are also investigated. G. Paul Sutton and Peter C. Jurs*, Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, Univer­ sity Park, PA 16802

Correspondence Chromatographic Detection of Interaction between Polyoxyethylene and Nitrous Acid 1891 Tetsuo Okada, Faculty of Liberal Arts, Shizuoka University, Shizuoka 422, Japan Multiple Mode Semiconductor Diode Laser as a Spectral Line Source for Graphite Furnace Atomic Absorption Spectroscopy 1893 Kin C. Ng, Abdalla H. Ali, Tye E. Barber, and James D. Winefordner*, Department of Chemistry, University of Florida, Gaines­ ville, FL 32611 Surface Acoustic Wave Detector for Screening Molecular Recognition by Gas Chromatography 1895 Michael Thompson* and David C. Stone, Department of Chemis­ try, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1A1, Canada

The number of confirmed analytes is approximately a factor of two lower than what would have been identified by the traditional one-column, one-detector system, and the number of false positive identifications is significantly reduced. Gregory S. Durell* and Theodor C. Sauer, Battelle Ocean Sciences, 397 Washington Street, Duxbury, MA 02332, and Marine Sciences Unit, Arthur D. Little, Inc., Acorn Park, Cambridge, MA 02140

87βΑ · ANALYTICAL CHEMISTRY, VOL. 62, NO. 17, SEPTEMBER 1, 1990

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Separation of Ethyl Methacrylate-Butyl Methacrylate Copolymers by Liquid Adsorption Chromatography with an Ultraviolet Absorption Detector

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