BRIEFS
Articles
Dual-Beam Optical Fiber Thermal Lens Spectroscopy
Operation of Ion-Selective Electrode Detectors in the Sub-Nernstian/Linear Response Range: Application to Flow Injection/Enzymatic Determination of L-Glutamine in Bioreactor Media 1906
A compact dual-beam optical fiber thermal lens spectrometer arrangement is developed by using optical fibers for the excitation beam and the aperture. Neodymium solutions a r e used to d e m o n s t r a t e t h e system sensitivity. Dorys Rojas, Robert J. Silva, Jonathan D. Spear, and Richard E. Russo*, Lawrence Berkeley Laboratory, Applied Science Division, MS 90-2024, Berkeley, CA 94720
The use of a FIA diluent stream containing high levels of interfering cations allows the use of an ammonium ionselective membrane electrode as a low-signal/linear detector for an enzyme-based L-glutamine sensing system. A split-line single detector arrangement enables convenient compensation for varying levels of endogenous ammonium ions within injected bioreactor media samples. Wojciech Matuszewski, Sara A. Rosario, and Mark E. Meyerhoff*, Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109 Voltammetric Measurement of Bimolecular Electron-Transfer Rates in Low Ionic Strength Solutions 1909 Steady-state voltammetry at platinum microdisk electrodes is used to estimate rate constants of bimolecular electron-transfer reactions. John D. Norton, Wendy E. Benson, and Henry S. White*, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 and Bradford D. Pendley and Hector D. Abruna*, Department of Chemistry, Baker Laboratory, Cornell University, Ithaca, NY 14853 Immobilization of Thin Enzyme Membranes To Construct Glass Enzyme Electrodes 1914 A technique for immobilizing thin layers of enzymes over glass-bodied electrodes is described. The resulting enzyme layers are 1-2 urn thick and response times are 5 - 1 0 s. The technique can be used to immobilize proteins over different supports and to construct biosensors and bioreactors. Satish Kumaran*, Helmut Meier, A. M. Danna, and C. Tran-Minh, Laboratoire de Genie Industriel et Biotechnologie, Ecole des Mines de Saint-Etienne, 158, cours Fauriel, 42023 Saint- Etienne Cedex, France Topology and Vaporization Characteristics of Palladium, Cobalt, Manganese, Indium, and Aluminum on a Graphite Surface Using Electrothermal Atomic Absorption 1918 Absorbance data are analyzed in several ways to deduce analyte form, desorption energies, and interactions with a heated graphite surface. J. McNally and J. A. Holcombe*, Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, TX 78712
1927
Increased Analytical Precision in the Hollow Cathode Discharge Emission Source by Improved Discharge Current Control 1933 Improvements in the precision of the hollow cathode emission source are reported. The improved precision is attributed primarily to the introduction of new electronics. Temporal current plots are presented for the new instrumentation. Jih-Lie Tseng and J. C. Williams*, Department of Chemistry, Memphis State University, Memphis, TN 38152, Robert B. Bartlow and Steven T. Griffin, Department of Electrical Engineering, Memphis State University, Memphis, TN 38152, and James C. Williams, Jr., Department of Anatomy and Cell Biology, Medical University of South Carolina, Charleston, SC 29425 Trace-Concentration Detection of Cobalt in a Liquid Flow Cell by Degenerate Four-Wave Mixing Using Low-Power Off-Resonant Laser Excitation 1943 Detection of 4.4 pmol Co(II) in ethanol, with minimum measurable absorbance of 2 x 10~5, by degenerate fourwave mixing using an analyte flow cell with a 0.14-uL laser probe volume is reported. Zhiqiang Wu and William G. Tong*, Department of Chemistry, San Diego State University, San Diego, CA 92182 Detection of Biomolecules on Surfaces Using lon-Beam-lnduced Desorption and Multiphoton Resonance Ionization 1947 Analysis of the composition of thermally labile molecules on surfaces using ion-beam-induced desorption coupled with laser postionization is described. Quantitative analysis in the femtomole range is possible for serotonin. D. M. Hrubowchak, M. H. Ervin, M. C. Wood, and Nicholas Winograd*, Department of Chemistry, 152 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802
Corresponding author 862 A • ANALYTICAL CHEMISTRY, VOL. 63, NO. 18, SEPTEMBER 15, 1991
BRIEFS Molecular Weight Distributions of Polymers Using Time-of-Flight Secondary Ion Mass Spectrometry 1953 Molecular weight distributions for perfluoropolyethers are obtained using TOF SIMS. Number-averaged molecular weights agree well with values determined by conventional techniques. loannis V. Bletsos and David M. Hercules*, Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 and Dieter van Leyen, Birgit Hagenhoff, Ewald Niehuis, and Alfred Benninghoven, Physikalisches Institut der Universitat Minister, D-4400 Minister, F.R.G. Development of a Low-Power Microwave Atmospheric Pressure Molecular Ionization Source for Mass Spectrometry with Direct Introduction of Gaseous and Liquid Organic Samples 1960 This ion source can sustain a He plasma at 1 0 - 3 0 W during introduction of gaseous or liquid samples and produce quasi-molecular parent ions as well as molecular fragments of analyte at atmospheric pressure. Wei-Lung Shen and R. D. Satzger*, U.S. Food and Drug Administration, National Forensic Chemistry Center, 1141 Central Parkway, Cincinnati, OH 45202 Detection of Petroleum-Based Accelerants in Fire Debris by Target Compound Gas Chromatography/Mass Spectrometry 1964 A GC/MS method for identifying accelerants in highly contaminated arson debris extracts is presented. Target compound data are replotted to produce patterns for comparison against a library of petroleum distillate patterns. Raymond O. Keto* and Philip L. Wineman, Forensic Science Laboratory, Bureau of Alcohol, Tobacco, and Firearms, U.S. Department of the Treasury, 1401 Research Boulevard, Rockville, MD 20850 Charge Determination of Product Ions Formed from Collision-Induced Dissociation of Multiply Protonated Molecules via Ion/Molecule Reactions 1971 Determination of the charges of selected product ions from melittin, bovine insulin, and myoglobin are illustrated using either proton transfer or clustering reactions with 1,6-diaminohexane in a quadrupole ion trap. Scott A. McLuckey*, Gary L. Glish, and Gary J. Van Berkel, Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6365 Optimization of the Fragmentation in a Frit-Fast Atom Bombardment Ion Source for the Sequencing of Peptides at the Picomole Level 1978 A frit-FAB interface is evaluated and optimized to enhance the amount of structural information available during an LC/MS analysis. Peptides derived from the enzymatic digestion of a model antigen, Staphylococcus aureus nuclease, and the exopeptidase, yeast aminopeptidase B, demonstrate the ability to assign amino acid sequences to peptides directly from their LC/MS spectra. D. B. Kassel*, K. P. Williams, B. D. Musselman, and J. A. Smith, Departments of Molecular Biology and Pathology, Massachusetts General Hospital, Boston, MA 02114, Departments of Genetics and Pathology, Harvard Medical School, Boston, MA 02114, and JEOL USA, Inc., Peabody, MA 01960
Determination of Dissolved Selenium Species in Environmental Water Samples Using Isotope Dilution Mass Spectrometry 1984 Selenite, selenate, trimethyl selenonium, and basic acidic organoselenium compounds are determined in natural fresh water samples in the range 10 pg/g to 15 ng/g. Dieter Tanzer and Klaus G. Heumann*, Institut fiir Anorganische Chemie, Universitat Regensburg, Universitatsstrasse 31, D-8400 Regensburg, Germany Electrospray-lon Spray: A Comparison of Mechanisms and Performance 1989 The mechanism of charged droplet and gas-phase ion formations in electrospray and ion spray is examined on the basis of experiments with a triple quadrupole atmospheric pressure ionization mass spectrometer. Michael G. Ikonomou, Arthur T. Blades, and Paul Kebarle*, Chemistry Department, University of Alberta, Edmonton, Alberta T6G 2G2, Canada Determination of Ethylenethiourea in Crops Using Particle Beam Liquid Chromatography/Mass Spectrometry 1999 The 5-ppb detection limit for ETU in crops is comparable to that obtained by LC-EC. No coelution ion abundance enhancement effects are observed. Daniel R. Doerge* and Carl J. Miles, Department of Environmental Biochemistry, University of Hawaii, 1800 East West Road, Honolulu, HI 96822 Isolated Dual Trapped Ion Cell Assembly for Fourier Transform Ion Cyclotron Resonance Mass Spectrometry 2001 Unit ionization duty cycle is achieved in an isolated, high magnetic field, source-trapped ion cell for FT-ICRMS. A 30-fold increase in sensitivity compared with dual cell designs is demonstrated. Steven A. Hofstadler and David A. Laude, Jr.*, Department of Chemistry and Biochemistry, The University of Texas, Austin, TX 78712 Liposome Flow Injection Immunoassay: Model Calculations of Competitive Immunoreactions Involving Univalent and Multivalent Ligands 2007 Relative effects of parameters such as binding constants, concentrations of liposomes and antibody, and steric hindrance on detectable liposome signal response to analyte concentrations are studied. Qualitative comparisons of the model with the experimental data are made. William T. Yap*, Laurie Locascio-Brown, Anne L. Plant, Steven J. Choquette, Viola Horvath, and Richard A. Durst, Center for Analytical Chemistry, NIST, Gaithersburg, MD 20899
864 A • ANALYTICAL CHEMISTRY, VOL. 63, NO. 18, SEPTEMBER 15, 1991
BRIEFS Development of a Miniaturized Gas Chromatograph-Mass Spectrometer with a Microbore Capillary Column and an Array Detector 2012 Mass spectra of narrow GC peaks eluted from a microbore column are measured using a mass spectrograph with an array detector. The suitability of the technique for the development of a field-portable GC/MS instrument is discussed. Mahadeva P. Sinha*, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 and George Gutnikov, Department of Chemistry, California State Polytechnic University, Pomona, CA 91768 Gas Chromatographic Determination of Water after Reaction with Triethyl Orthoformate
2016
Water reacts with an ortho ester in an acid-catalyzed reaction to form an alcohol and a carboxylic acid ester. GC measurement of one of these products is used to quantify the amount of water in the sample. Jian Chen and James S. Fritz*, Ames Laboratory-U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames IA 50011 Prediction of Gas Chromatographic Relative Retention Times of Stimulants and Narcotics 2021 A quantitative structure-retention relationship study is done using 57 stimulants, narcotics, and metabolites. Two models for relative retention time are developed with the full set and a subset of the compounds. C. G. Georgakopoulos and J. C. Kiburis, Doping Control Laboratory, The Olympic Athletic Center of Athens, Kifissias 37, 15123 Maroussi, Athens, Greece and P. C. Jurs*, Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, PA 16802 Prediction of Gas Chromatographic Relative Retention Times of Anabolic Steroids 2025 A quantitative structure-retention relationship study is done using 45 anabolic steroids and metabolites. A 9-variable model with a relative standard error of < 3% is found for relative retention time. C. G. Georgakopoulos, O. G. Tsika, and J. C. Kiburis, Doping Control Laboratory, The Olympic Athletic Center of Athens, Kifissias 37, 15123 Maroussi, Athens, Greece and P. C. Jurs*, Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, PA 16802 Role of the Modulator in Gradient Eiution Chromatography 2028 The possible consequences of modulator shock formation on gradient separations are examined using a series of numerical simulations. Ajoy Velayudhan and Michael R. Ladisch*, Laboratory of Renewable Resources Engineering and Department of Agricultural Engineering, Purdue University, West Lafayette, IN 47907-1295
Electrical Double-Layer Model for Ion-Pair Chromatographic Retention on Octadecylsilyl Bonded Phases 2032 Rentention of a sample ion in the presence of a "pairing ion" is shown quantitatively to be the result of both dynamic ion exchange and surface adsorption. Hanjiu Liu and Frederick F. Cantwell*, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2 Capillary Gel Affinity Electrophoresis of DNA Fragments 2038 The use of ethidium bromide as a soluble complexing agent for the polyacrylamide capillary gel electrophoresis of DNA fragments is described. Andras Guttman* and Nelson Cooke, Beckman Instruments, Inc., Palo Alto, CA 94304 Optimization in Sample Stacking for High-Performance Capillary Electrophoresis 2042 The optimal condition for sample stacking in CE using both a simple theoretical model and experimental data is investigated. A field enhancement factor (7) of 8 gives the best stacking conditions. Dean S. Burgi and Ring-Ling Chien*, Varian Research Center, 3075 Hansen Way, Palo Alto, CA 94304-1025 Calibrated Chemical Amplifier for Atmospheric R0X Measurements 2048 A modified radical amplifier with absolute radical calibration that is less sensitive to interferences is described. It h a s a chain length of 120 and a radical detection limit of < 2 pptv. Donald R. Hastie, Michael Weissenmayer, John P. Burrows*, and Geoffrey W. Harris, Air Chemistry Department, Max-Planck Institute for Chemistry, Saarstrasse 23, Postfach 3060, D-6500 Mainz, Germany General Theory of Excitation in Ion Cyclotron Resonance Mass Spectrometry 2057 For ions initially at rest, the ICR orbital (or magnetron) radius is proportional to the spectral magnitude of the time-domain waveform at the orbital (or magnetron) frequency. Peter B. Grosshans and Alan G. Marshall*, Department of Chemistry, The Ohio State University, 120 West 18th Avenue, Columbus, OH 43210
Correspondence Pulsed Flame—A Novel Concept for Molecular Detection 2061 Eitan Atar, Sergey Cheskis, and Aviv Amirav*, School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel Preforming Ions in Solution via Charge-Transfer Complexation for Analysis by Electrospray Ionization Mass Spectrometry 2064 Gary J. Van Berkel*, Scott A. McLuckey, and Gary L. Glish, Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6365
866 A • ANALYTICAL CHEMISTRY, VOL. 63, NO. 18, SEPTEMBER 15, 1991
BRIEFS
Who Says Chromatography Isn't Rewarding?
0n-Line Single-Particle Analysis by Laser Desorption Mass Spectrometry 2069 P. J. McKeown and M. V. Johnston*, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 and D. M. Murphy*, Aeronomy Laboratory, NOAA/ERL, Boulder, CO 80303
Technical Notes Design and Evaluation of an Electrochemical Cell for the Study of Organometallic Complexes at Increased Gas Pressures 2073 James E. Anderson* and Eileen T. Maher, Department of Chemistry, Boston College, Chestnut Hill, MA 02167 Use of an On-Column Fracture in Capillary Zone Electrophoresis for Sample Introduction 2076 Michael C. Linhares* and Peter T. Kissinger, Department of Chemistry, Purdue University, West Lafayette, IN 47907 Determination of Halocarbons in Drinking Water by Direct Aqueous Injection Gas Chromatography 2078 Hou Dingyuan* and Tang Jianfei, Suzhou Environmental Monitoring Central Station, Suzhou, 215004 People's Republic of China
Perkin-Elmer International Liquid Chromatography Technical Paper Award Applications are now being accepted for The 1991 Perkin-Elmer International Liquid Chromatography Technical Paper Award. %> Deadline for submissions is January 1,1992. ^ Papers written and/or published in 1990 or 1991 are eligible. ^ Technical content of the paper is unrestricted as long as the analytical technique used is liquid chromatography. ^& A first-place prize of $20,000 (U.S. List Price) of Perkin-Elmer equipment and a second-place prize of $5,000 (U.S. List Price) of PE XPRESS consumables will be awarded to the authors' employers. %> All papers must be submitted in English, and be accompanied by an application form.
For complete rules and an application form, call 1-800-762-4000 (in the U.S.), (203) 762-6011 (outside the U.S.), or fax your request to: (203) 762-6037.
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ELMER
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868 A • ANALYTICAL CHEMISTRY, VOL. 63, NO. 18, SEPTEMBER 15, 1991
