BRIEFS
Articles Selectivity of Membrane Electrodes Based on Derivatives of Dibenzyltin Dichloride 754 Selectivity properties are presented for membrane elec trodes based on the incorporation of bis(/>-methylbenzyl)tin dichloride, dibenzyltin dichloride, and bis(/>-chlorobenzyDtin dichloride in plasticized polymer membranes. Electrode response is selective for phosphate in the pres ence of potentially interfering anions, and a hypothesis is proposed that relates the structure of the organotin com pound to the selectivity for phosphate. Scott A. Glazier and Mark A. Arnold*, Department of Chem istry, University of Iowa, Iowa City, IA 52242 Automated Potentiometric Determination of Sulfur Functional Groups in Fossil Fuels 760 The sample is heated nonisothermally in a reducing at mosphere to liberate sulfur functional groups as H 2 S at discrete temperature ranges. A stream of N 2 takes the BUS into an alkaline solution where it is determined as S as a function of time or temperature. Bernard B. Majchrowicz, Jan Yperman*, Jules Mullens, and Lucien C. Van Poucke, Laboratory of Inorganic & Physi cal Chemistry, Limburgs Universitair Centrum, B-3590 Diepenbeek, Belgium Coated-Wire Ion-Selective Electrode for the Determination of Antimony(V) 764 A near-Nernstian response (-58.4 mV) is obtained over the concentration range 5 χ 10~ 7 -10 - 3 M, with response times within 10 s. Detection limit, standard deviation, and selectivity coefficient (for 21 common ions) are 10~7 M, ± 0.69 mV, and < 10~5, respectively. Concepcion Sânchez-Pedreno*, Joaquin A. Ortufto, and Joaquin Alvarez, Department of Analytical Chemistry, Faculty of Sciences, University of Murcia, 30071 Murcia, Spain Multivariate Prediction and Background Correction Using Local Modeling and Derivative Spectroscopy 767 Two techniques based on regression modeling of spectra are described to accurately estimate the concentration of analytes in the presence of background constituents. Reliable predictions for two data sets are obtained. Terje V. Karstang* and Olav M. Kvalheim, Department of Chemistry, University of Bergen, N-5007 Bergen, Norway
•Corresponding author 436 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 8, APRIL 15, 1991
Effect of Ascorbic Acid on Graphite Furnace Atomic Absorption Signals for Lead 772 Double-peak signals for lead are observed in the presence of ascorbic acid when the nonpyrolytic coated graphite tube and the pyrolytic graphite tube are used. Shoji Imai* and Yasuhisa Hayashi, Department of Chemistry, Joetsu University of Education, Joetsu, Niigata 943, Japan Double-Injection Flow Injection Analysis Using Multivariate Calibration for Multicomponent Analysis 775 Multivariate calibration methods include classical least squares, principal components regression, and partial least squares. Moderate sampling rates and small calibration sets can be used. David A. Whitman, Mary Beth Seasholtz, Gary D. Christian*, Jarda Ruzicka, and Bruce R. Kowalski, Center for Process Analytical Chemistry, Department of Chemistry, University of Washington, Seattle, WA 98195
Reversed-Phase Liquid Chromatography/Fourier Transform Infrared Spectrometry Using Concentric Flow Nebulization 782 A technique for direct deposition HPLC/FT-IR in which solutes in aqueous solvents are deposited as spots < 150 μπι in diameter is demonstrated. The minimum de tectable quantity is < 500 pg. Andrew J. Lange and Peter R. Griffiths*, Department of Chemistry, University of Idaho, Moscow, ID 83843 and David J. J. Fraser, Department of Chemistry, University of Califor nia, Riverside, Riverside, CA 92521 High Mass Resolution Secondary Ion Mass Spectrometry via Simultaneous Detection with a Charge-Coupled Device 788 A method for the efficient acquisition of high mass reso lution secondary ion mass spectra is presented. Trace analyses and depth profiles at mass resolutions exceeding 10 000 M/AM are demonstrated. David S. Mantus, Gary A. Valaskovic, and George H. Mor rison*, Baker Laboratory of Chemistry, Cornell University, Ith aca, NY 14853-1301 Sensitivity Enhancement of Fluorescent pH indicators by Inner Filter Effects 793 Primary and secondary inner filter effects used with mul tiple indicator systems enhance the sensitivity of fluores cence pH measurements. The indicator systems exam ined provide increases in the pH titration curve slopes of 1.43-4.00. Gavriella Gabor and David R. Walt*, Department of Chemis try, Max Tishler Laboratory for Organic Chemistry, Tufts Uni versity, Medford, MA 02155
BRIEFS
Determination of the Transduction Mechanism for Optical Sensors Based on Rhodamine 6G Impregnated Perfluorosulfonate Films Using Steady-State and Frequency-Domain Fluorescence 797 Models based on ion pairing are developed to explain the transduction mechanism of previously reported humidity and metal sensors t h a t use rhodamine 6G-impregnated perfluorosulfonate membranes as the sensing elements. Kevin S. Litwiler, Pamela M. Kluczynski, and Frank V. Bright*, Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14214 On-Column Sample Gating for High-Speed Capillary Zone Electrophoresis 802 Capillary electrophoresis is used to separate a mixture of amino acids in times as short as 1.5 s. Elevated electric fields and a short column length allow reduced analysis times while still maintaining separation efficiency. Curtis A. Monnig and James W. Jorgenson*, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290 Sample Gating in Open Tubular and Packed Capillaries for High-Speed Liquid Chromatography 807 Open tubular liquid chromatography columns with oncolumn sample gating and short column lengths are used to separate a mixture of amines in as little as 6 s. Curtis A. Monnig, Daniel M. Dohmeier, and James W. Jor genson*, Department of Chemistry, University of North Caroli na, Chapel Hill, NC 27599-3290 Liquid-Liquid Extraction of Organometallic and Inorganic Germanium as the Chloride Complex 811 Germanium compounds are separated based on a liquidliquid extraction involving aqueous hydrochloric acid and carbon tetrachloride. The effect of σ-bonded organic ligands on the extraction is discussed. Yoshiki Sohrin, Institute for Chemical Research, Kyoto Uni versity, Uji, Kyoto 611, Japan Determination of Molecular Weight Distributions of terf-Octylphenol Ethoxylate Surfactant Polymers by Laser Desorption Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and High-Performance Liquid Chromatography
815 Laser desorption FT-ICRMS provides accurate molecular weight distributions for one class of surfactant oligomers and is particularly useful for polymers with molecular weights too high for HPLC analysis. Zhenmin Liang and Alan G. Marshall*, Departments of Chemistry and Biochemistry, The Ohio State University, 120 West 18th Avenue, Columbus, OH 43210 and David G. West moreland*, Rohm and Haas Company, 727 Norristown Road, Spring House, PA 19477
438 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 8, APRIL 15, 1991
Determination of Chlorinated Phenoxy Acid and Ester Herbicides in Soil and Water by Liquid Chromatography Particle Beam Mass Spectrometry and Ultraviolet Absorption Spectrophotometry 819 Herbicides are determined by LC using UV absorption for quantitation and particle beam MS for confirmation. Full-scan electron ionization spectra are given. Quantita tion limits are 4.8-32 ppb in water and 20-133 ppb in soil. In Suk Kim, Fassil I. Sasinos, Robert D. Stephens, Jeanny Wang, and Mark A. Brown*, Hazardous Materials Laborato ry, California Department of Health Services, 2151 Berkeley Way, Berkeley, CA 94704 Micellar Electrokinetic Capillary Chromatography of Illicit Drug Substances 823 Illicit drug substances are separated by using micellar electrokinetic capillary chromatography. The technique is well suited for general screening of bulk illicit materials. Robert Weinberger*, Applied Biosystems, Inc., 170 Williams Drive, Ramsey, NJ 07446 and Ira S. Lurie, Drug Enforcement Administration, Special Testing and Research Laboratory, 7704 Old Springhouse Road, McLean, VA 22102
Quantitative Retention-Biological Activity Relationship Study by Micellar Liquid Chromatography 828 A single retention parameter is adequate in predicting bioactivity of phenols. For comparison, a QSAR study re quires t h r e e conventional molecular descriptors to achieve a similar correlation. Emelita D. Breyer, Joost K. Strasters, and Morteza G. Khaledi*, North Carolina State University, Department of Chemistry, P.O. Box 8204, Raleigh, NC 27695 Determination of Isotherms from Chromatographic Peak Shapes 833 A computation-based method for determining isotherms from experimental chromatographic peak shapes is pre sented. The method performs well at low column efficien cy, and results agree with those from frontal analysis. Eric V. Dose, Stephen Jacobson, and Georges Guiochon*, Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, and Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6120
Correspondence Linear Scan and Staircase Voltammetry of Adsorbed Species 839 Zbigniew Stojek and Janet Osteryoung*, Department of Chemistry, SUNY University of Buffalo, Buffalo, NY 14214
From NEW!
Tekmar®
BF?IEF=S
Technical Notes Chromatographic Separation of Arsenic Species with Sodium Bis(trifluoroethyl)dithiocarbamate Chelation 842 Jya-Jyun Yu and C. M. Wai*, Department of Chemistry, University of Idaho, Moscow, ID 83843
The Tekmar 7000
— Best Automation Value at $290 per Sample Position with 50 Sample Capacity • Easily Interfaces to All GC or GC/MS Systems • Temperature Range Up to 200°C...
Headspace
Autosampler
and MUCH MORE! For more information and our
FREE CATALOG
Call Now!
(800) 543-4461 tside the U.S. and Canada (513) 247-7000 · Telefax (513) 247-7050 · Telex 21 P.O. BOX 429576 Cincinnati, Onto 45242-9576
CIRCLE 132 ON READER SERVICE CARD
WAVE 1000
M I C R O W A V E
D I G E S T I O N
Everything The EPA W a n t e d . . . Temperature Control · 1000 Watts Delivered Thermally Balanced Vessels · 8086 Programmability And M o r e . . . Sealed Pressure Control · Low Cost Vessel Liners Remote Operation · PFA Lined Oven · Modular Design
Concurrent Pressure/Temperature Mode And Still More. Questron's "24 Hour Service Response" Lifetime Applications Support
Designed and Built by Questran Systems. Sold, Serviced and Supported by Question Corporation.
P.O. Box 2387 Princeton, NJ 08543-2387 609-587-6898 · FAX: 609-587-0513
QUESTRON CORPORATION
CIRCLE 117 ON READER SERVICE CARD
440 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 8, APRIL 15, 1991
Amperometric High-Performance Liquid Chromatographic Detection of NADH at a Base-Activated Glassy Carbon Electrode 845 Eugene J. Eisenberg* and Kenneth C. Cundy, Department of Drug Delivery, Sterling Research Group, Great Valley, PA 19355
Correction. Determination of Metal Ions by Capillary Zone Electrophoresis with On-Column Chelation Using 8-Hydroxyquinoline-5-sulfonic Acid 848 David F. Swaile and Michael J. Sepaniak*, Department of Chemistry, The University of Tennessee, Knoxville, TN 379961600
Correction. Applications of Dioxetane Chemiluminescent Probes to Molecular Biology 848 Stephen Beck* and Hubert Kôster, MilliGen/Biosearch, 186 Middlesex Turnpike, Burlington, MA 01803
