BRIEFS
Supersonic Jet/Synchronous Scan Luminescence Spectrometry 1362
Spectroscopic Investigation of the Mechanisms of the Alkali Bead Detector for Gas Chromatography 1380
This technique greatly simplifies the spectrum obtained by supersonic jet spectrometry alone and gives a single peak for a single component in most cases. Identification of the molecule can readily be performed from the peak position. Totaro Imasaka, Atsushi Tsukamoto, and Nobuhiko Ishibashi*, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812, Japan Anal. Chem., 60 (1988)
Emission and laser-induced fluorescence measurements show that the detector can be made of ordinary soda glass, alkali atoms are lost by exchange with hydrogen, and ionization occurs in the gas phase. Peter van de Weijer* and Bauke H. Zwerver, Philips Research Laboratories, P.O. Box 80.000, 5600 JA Eindhoven, The Netherlands, and Roderick J. Lynch, Philips Scientific, York Street, Cambridge CB1 2PX, Great Britain Anal. Chem., 60 (1988)
Evaluation of a Supercritical Fluid Chromatograph Coupled to a Surface-Wave-Sustained Microwave-Induced Plasma Detector 1365
Portable Double-Beam, Fiber-Optic-Based Photometric Comparator
A microwave-induced plasma is successfully coupled to a supercritical fluid chromatograph. The range of detection limits for a model mixture of sulfur-containing polyaromatic compounds is 25-150 pg/s of sulfur. The linear dynamic range is 3 orders of magnitude with relative standard deviations of less than 5%. Debra R. Luffer, Leonard J. Galante, Paul A. David, Milos Novotny*, and Gary M. Hieftje, Department of Chemistry, Indiana University, Bloomington, IN 47405 Anal. Chem., 60 {1988) Characterization of Microwave-Induced Plasma as a Detector for Supercritical Fluid Chromatography 1370 A low-power helium microwave-induced plasma sustained in the surface-microwave-induced plasma (surfatron) shows good promise as a detector for SFC. The influence of common mobile phases on sensitivity and spectral background is discussed. Leonard J. Galante, Mark Selby, Debra R. Luffer, Gary M. Hieftje*, and Milos Novotny, Department of Chemistry, Indiana University, Bloomington, IN 47405 Anal. Chem., 60 (1988)
Computer-Controlled Flow Injection Analysis System for OnLine Determination of Distribution Ratios 1390 An automated FIA system rapidly produces metal extraction distribution ratio data that are comparable to batch methods. The precision of replicate D values is usually within 10%. Howard L. Nekimken*, Barbara F. Smith*, Gordon D. Jarvinen, E. J. Peterson, and Marianne M. Jones, Chemical and Laser Sciences Division, Analytical Chemistry Group, MS G740, Los Alamos National Laboratory, Los Alamos, NM 87545 Anal. Chem., 60 (1988)
Substituted 3,3-Diphenylphthalides as Optochemical Sensors for Polar Solvent Vapors 1377 3,3-Diphenylphthalides interact with an acid component to yield triphenylcarbenium ions that can be applied in thin layers as an optochemical sensor. The change in absorbance makes it possible to detect the vapors of polar solvents in the air down to 10 ppm. F. L. Dickert*, E. H. Lehmann, and S. K. Schreiner, Institute of Physical and Theoretical Chemistry, Erlangen University, Egerlandstrasse 3, D-8520 Erlangen, FRG, and Heinz Kimmel and G. R. Mages, Siemens AG, Central Research and Development ZFE AMF 32, Paul-Gossen-Strasse 100, D-8520 Erlangen, FRG Anal. Chem., 60 (1988)
* Corresponding author
1387
A photometer is developed that makes direct comparisons of the transmittance of two solutions. The instrument, which operates in a double-beam mode for high stability, minimizes the effects of light source drift and stray light and can be used for simultaneous referencing. A light-emitting diode is used as the light source with a bifurcated fiber optic for light transport. Paul R. Kraus, Adrian P. Wade, and S. R. Crouch*, Department of Chemistry, Michigan State University, East Lansing, MI 48824, J. F. Holland, Department of Biochemistry, Michigan State University, East Lansing, MI 48824, and Brinton M. Miller, Neogen Corporation, 620 Lesher Place, Lansing, MI 48912 Anal. Chem., 60 (1988)
Investigation of Poly(L-amino acids) by X-ray Photoelectron Spectroscopy 1393 XPS is used to systematically characterize amino acids. The observed binding energies and intensities can be explained in terms of the expected structures. Human serum albumin is also examined. Kenneth D. Bomben*, The Perkin-Elmer Corporation, Physical Electronics Laboratory, 1161-C San Antonio Road, Mountain View, CA 94043, and Sukhendu B. Dev, Battelle Columbus Division, 505 King Avenue, Columbus, OH 43201 Anal. Chem., 60 (1988)
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814 A · ANALYTICAL CHEMISTRY, VOL 60, NO. 14, JULY 15, 1988
BRIEFS Liquid Chromatographic Separation of Phosphorus Oxo Acids and Other Anions with Postcolumn Indirect Fluorescence Detection by Aluminum-Morin 1397
Quantification of LSD and N-emethyl-LSD in Urine by Gas Chromatography/Resonance Electron Capture Ionization Mass Spectrometry 1420
Phosphorus oxo acids including organodiphosphonates are separated by anion exchange and detected indirectly by postcolumn aluminum-morin fluorescence change with de tection limits approaching 15 ng. Shon E. Meek and D. J. Pietrzyk*, Department of Chemistry, University of Iowa, Iowa City, IA 52242 Anal. Chem., 60 (1988)
A GC/resonance electron capture ionization MS assay for lysergic acid diethylamide (LSD) and iV-demethyl-LSD in urine is developed. LSD is measured in urine collected from a volunteer for up to 22 h following oral administration of the drug. iV-Demethyl-LSD is detected and measured in urine specimens collected for up to 72 h after administration. Heng Keang Lim, David Andrenyak, Paula Francom, and Rodger L. Foltz*, Center for Human Toxicology, University of Utah, Salt Lake City, UT 84112, and Reese T. Jones, Langley Porter Neuropsychiatrie Institute, University of California, San Francisco, CA 94143 Anal. Chem., 60 (1988)
Application of a CF3+ Primary Ion Source for Depth Profiling in Secondary Ion Mass Spectrometry 1401 The performance of a CF34" primary ion source in SIMS for some typical depth-profiling applications is compared with the results obtained with a conventionally used C>2+ source. At the same accelerating potential, steady-state secondary ion emission conditions are reached much faster under CF3 + than under C>2+ bombardment. Wilhad Reuter* and Gerald J. Scilla, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598 Anal. Chem., 60 (1988) Secondary Ion Emission and Sputter Yields from Metal Targets under F 2 + Bombardment 1404 Sputter yields and relative ionization probabilities are de termined after saturation bombardment of 13 elements by using a mass-separated 10-keV F 2 + primary beam. Wilhad Reuter* and J. G. Clabes, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598 Anal. Chem., 60 (1988) Resonant Two-Photon Ionization of Enkephalins and Related Peptides Volatilized by Using Pulsed Laser Desorption in Supersonic Beam Mass Spectrometry 1409 In the laser-induced multiphoton ionization of Leu- and Met-enkephalin, the fragments produced include character istic acylium and aldimine ions as well as cleavage at the aromatic moiety. A substantial molecular ion, M*+, is ob served in every case. Liang Li and David M. Lubman*, Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109 Anal. Chem., 60 (1988) Computer-Based Linear Regression Analysis of Desorption Mass Spectra of Microorganisms 1415 A system is described for library matching of single un knowns and for mixture analysis of microorganisms by using the lipid profiles of lysed cells obtained by negative-ion FAB-MS. J. A. Piatt and Ο. Μ. Uy, The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20707, and D. N. Heller*, R. J. Cotter, and Catherine Fenselau, Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205 Anal. Chem., 60 (1988)
Effect of Primary Beam Energy on the Secondary Ion Sputtering Efficiency of Liquid Secondary Ionization Mass Spectrometry in the 5-30-keV Range 1426 A comparison of integrated secondary ion signals produced by Cs + primary beam energies between 5 and 30 keV indi cates a maximum ion secondary efficiency at 15-20-keV primary energy. William H. Aberth* and A. L. Burlingame, University of Califor nia, Department of Pharmaceutical Chemistry, Mass Spectrometry Facility, San Francisco, CA 94143-0446 Anal. Chem., 60 (1988) High-Resolution Mass Spectrometric Determination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans Using an Alternative Lockmass System 1429 A variety of samples and standards are analyzed to show that reproducibility is comparable and sensitivity is enhanced with this method when compared with conventional meth ods. Vince Y. Taguchi*, Eric J. Reiner, David T. Wang, Otto Meresz, and Bernard Hallas, Ontario Ministry of the Environ ment, P.O. Box 213, Rexdale, Ontario, Canada M9W 5L1 Anal. Chem., 60 (1988) Corrections for Secondary Relaxation in Exponentially Programmed Field-Flow Fractionation
1434
The nonequilibrium theory of secondary relaxation is ex tended and applied to exponentially programmed FFF. The range of validity of the model is examined, correction terms are derived, and practical guidelines are established. Marcia E. Hansen and J. Calvin Giddings*, Department of Chemistry, University of Utah, Salt Lake City, UT 84112, Mark R. Schure, Laboratory Data Products Group, Digital Equipment Cor poration, 1 Iron Way, MR02-4/E33, Marlborough, MA 01752, and Ronald Beckett, Water Studies Centre, Chisholm Institute of Technology, Caulfield East, Victoria, Australia 3145 Anal. Chem., 60 (1988)
816 A • ANALYTICAL CHEMISTRY, VOL. 60, NO. 14, JULY 15, 1988
BRIEFS Role of Temperature in the Behavior of Homologous Series in Reversed-Phase Liquid Chromatography 1443
Correspondence
Systematic measurements of the retention volumes of nine homologous series at different temperatures are made. The van't Hoff plots are linear in the temperature range studied (25-60 °C), and two convergence points are observed. Alain Tchapla* and Sylvie Heron, Laboratoire de Chimie Analytique Physique, Route de Saclay, 91128 Palaiseau Cedex, France, Henri Colin, Prochrom. B.P. 9, Chemin des Blanches, Terres, 54250 Champigneulles, France, and Georges Guiochon, Department of Chemistry, Georgetown University, Washington, DC 20057 Anal. Chem., 60 (1988)
Nonspectroscopic Internment Interferences in Inductively Coupled Plasma Mass Spectrometry 1472 George R. Gillson*, Donald J. Douglas, John E. Fulford, Ken neth W. Halligan, and Scott D. Tanner, SCIEX, 55 Glen Cameron Road, Thornhill, Ontario, Canada L3T 1P2 Anal. Chem., 60 (1988)
Determination of Hydrophilic Thiols in Sediment Porewater Using Ion-Pair Liquid Chromatography Coupled to Electrochemical Detection 1449 The simultaneous determination of 12 thiols by LCEC is optimized. The detection limits are about 2 pmol. Factors influencing detector response and sample stability are discussed. Damian Shea* and William A. MacCrehan, Center for Analytical Chemistry, National Bureau of Standards, Gaithersburg, MD 20899 Anal. Chem., 60 (1988)
Comments on the Testing of the Accuracy of an Extraction Procedure for Determining the Partitioning of Trace Metals in Sediments 1475 André Tessier* and Peter G. C. Campbell, INRS-Eau, C.P. 7500, Sainte-Foy, Québec, GlV 4C7, Canada, and C. F. Bauer* and C. Kheboian, Department of Chemistry, University of New Hampshire, Durham, NH 03824 Anal. Chem., 60 (1988) Comparison of Recovery Data Generated with and without an Injection Standard in Gas Chromatography/Mass Spectrometry Analysis 1478 Herman Valente* and Kenneth M. Aldous, Wadsworth Center for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201 Anal. Chem., 60 (1988)
Elimination of the Asymmetry in Neutral-Carrier-Based Solvent Polymeric Membranes Induced by Proteins 1455 Proteins induce asymmetry potentials in inherently symmetric solvent polymeric membranes of up to 2 mV. Ionselective electrodes based on a vinyl chloride/vinyl alcohol copolymer do not show such shifts in the cell potential. Lucas F. J. Durselen, Dorothée Wegmann, Kurt May, Urs Oesch, and Wilhelm Simon*, Department of Organic Chemistry, Swiss Federal Institute of Technology (ΕΤΗ), CH-8092 Zurich, Switzerland Anal. Chem., 60 (1988) Ellipsometric, Electrochemical, and Elemental Characterization of the Surface Phase Produced on Glassy Carbon Electrodes by Electrochemical Activation 1459 The comparison of the phase produced during electrochemi cal activation of glassy carbon electrodes, probed by ellipsometry, voltammetry, and elemental analysis, is postulated to be an amorphous form of graphite oxide. Larry J. Kepley and Allen J. Bard*, Department of Chemistry, The University of Texas, Austin, TX 78712 Anal. Chem., 60 (1988)
Technical Notes Determination of Molecular Nitrogen with a Photometric Detector 1481 You-Zhi Tang and Walter A. Aue*, Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3 Anal. Chem., 60 (1988) Cryogenically Cooled Interface for Gas Chromatography/Fourier Transform Infrared Spectrometry 1483 Robert S. Brown, Department of Chemistry, Colorado State University, Fort Collins, CO 80523, and Charles L. Wilkins*, Department of Chemistry, University of California, Riverside, Riverside, CA 92521 ' ' Anal. Chem., 60 (1988)
Electrochemical Oxidation of Nitrite on a Rotating Gold Disk Electrode: A Second-Order Homogeneous Disproportionation Process 1468 The rate for N 0 2 decomposition in acid calculated from the currents for N 0 2 ~ oxidation on a rotating Au electrode is (1.9 ± 0.5)·1010 cm 3 'mol _1 -s _1 . A diagnostic criterion for secondorder disproportionation processes is presented. Xuekun Xing and Daniel A. Scherson*, The Case Center for Electrochemical Sciences and the Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106 Anal. Chem., 60 (1988)
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