BRIEFS
Articles High-Pressure Phase Distribution Isotherms for Supercritical Fluid Chromatographic Systems. 1. Pure Carbon Dioxide 98 Mass spectrometric tracer pulse chromatography is used to measure the phase distribution isotherms for carbon dioxide in SE-30, on silica, and on Ci 8 -bonded silica over a range of sub- and supercritical temperatures and pressures. Joseph R. Strubinger, Hengchang Song, and Jon F. Parcher*, Department of Chemistry, University of Mississippi, University, MS 38677 High-Pressure Phase Distribution Isotherms for Supercritical Fluid Chromatographic Systems. 2. Binary Isotherms of Carbon Dioxide and Methanol 104 Mass spectrometric tracer pulse chromatography is used to measure the phase distribution isotherms for binary mix tures of carbon dioxide and methanol on silica and Cigbonded silica over temperature ranges from 50 to 100 °C and pressures from the critical pressure of the binary mixtures to 150 bar. Joseph R. Strubinger, Hengchang Song, and Jon F. Parcher*, Department of Chemistry, University of Mississippi, University, MS 38677 Determination of Bioactive Peptides Using Capillary Zone Electrophoresis/Mass Spectrometry 109 Mixtures of bioactive peptides are analyzed by on-line coaxi al continuous flow CZE/FABMS. Separation efficiencies >400 000 theoretical plates are obtained from mixtures of tens of femtomoles of analytes. CZE/MS and CZE/MS/MS data are acquired in electrophoretic real time. M. A. Moseley, Laboratory of Molecular Biophysics, National In stitute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, and Department of Chemistry, University of North Carolina, CB 3290, Chapel Hill, NC 27514, L. J. Deterding and Κ. Β. Tomer*, Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, P.O. Box 12233, Re search Triangle Park, NC 27709, and J. W. Jorgenson, Department of Chemistry, University of North Carolina, CB 3290, Chapel Hill, NC 27514 Hydrocarbon Type Determination of Naphthas and Catalytically Reformed Products by Automated Multidimensional Gas Chromatography 114 An automated gas chromatographic technique with multiple columns and detectors allows analysis of paraffins, naphthenes, and PNAs in naphtha and catalytically reformed product streams boiling below 220 °C. Julius J. Szakasits* and Robert E. Robinson, Shell Development Company, Westhollow Research Center, Houston, TX 77251-1380
•"Corresponding author
Peak Shape Analysis in Sedimentation Field-Flow Fractionation 120 Edgeworth-Cramér series numerical fitting is used to analyze peak shape and to detect and quantitate secondaryorder effects on retention parameters. Pierluigi Reschiglian, Gabriella Bio, and Francesco Dondi*, Department of Chemistry, University of Ferrara, V. L. Borsari, 46, 1-44100 Ferrara, Italy Isolation and Purification of Chlorophylls a and b for the Determination of Stable Carbon and Nitrogen Isotope Compositions
130
Chlorophyll pigments from plant tissues are isolated and purified by solvent precipitation and reversed-phase HPLC. The purity of the isolated pigments is determined by HPLC, absorption spectroscopy, elemental analysis, and Ή NMR. Robert R. Bidigare, Mahlon C. Kennicutt II*, and Wendy L. Keeney-Kennicutt, Geochemical & Environmental Research Group, 833 Graham Road, Texas A&M University, College Station, TX 77845, and Stephen A. Macko, Department of Earth Sciences, Memorial University, St. Johns, Newfoundland, Canada A1B 3X9 Pulsed Amperometric Detection of Aliphatic Alcohols in Liquid Chromatography 134 Simple alcohols and polyalcohols are detected under acidic and alkaline conditions at Pt and Au working electrodes, respectively. Under acidic conditions, pulsed amperometric detection offers ~ 2 - 3 orders of magnitude linearity and ~ 1 0.1 nmol limits of detection. William R. LaCourse* and Dennis C. Johnson, Department of Chemistry, Iowa State University, Ames, IA 50011 and Maria A. Rey and Rosanne W. Slingsby, Dionex Corporation, P.O. Box 3603, Sunnyvale, CA 94088-3603 Statistical Treatment for Rejection of Deviant Values: Critical Values of Dixon's "Q" Parameter and Related Subrange Ratios at the 9 5 % Confidence Level 139 Two-tailed critical values for Dixon's Q test and the related '"n, f 12, r-io, Γ21, and r22 parameters for the statistical rejection of outliers are interpolated for the 95% confidence level by cubic regression analysis based on published values for the 80, 90, 96, 98, and 99% confidence levels. Errors in Dixon's original tables are also identified and corrected. David B. Rorabacher, Department of Chemistry, Wayne State University, Detroit, MI 48202 Frequency-Domain Spectroscopic Study of the Effect of /i-Propanol on the Internal Viscosity of Sodium Dodecyl Sulfate 146 Micelles Frequency-domain fluorescence anisotropy studies of tetracene in sodium dodecyl sulfate micelles show that rc-propanol lowers the viscosity of the interior of the micelle and that the micelle interior is structurally disordered. M. J. Wirth*, S.-H. Chou, and D. A. Piasecki, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716
50 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 2, JANUARY 15, 1991
BRIEFS Expansion of Dynamic Working Range and Correction for Interferences in Flame Atomic Absorption Spectrometry Using Flow-Injection Gradient Ratio Calibration with a Single Standard 151 T h e r a n g e can be e x p a n d e d by using t h e information from t h e t r a n s i e n t signal p r o d u c e d b y flow-injection s a m p l e pres e n t a t i o n . An a l g o r i t h m is p r o p o s e d t h a t covers t h e entire calibration range with only one reference solution a n d t h a t corrects for m a t r i x interferences a t t h e s a m e t i m e . Michael Sperling, Zhaolun F a n g , and B e r n h a r d Welz*, Department of Applied Research, Bodenseewerk Perkin-Elmer GmbH, D-7770 Uberlingen, FRG
Determination of Metal Ions by Capillary Zone Electrophoresis with On-Column Chelation Using 8-Hydroxyquinoline-5-sulfonic Acid 179 Ca(II), Mg(II), a n d Zn(II) are s e p a r a t e d by CZE based on t h e i r i n t e r a c t i o n w i t h 8-hydroxyquinoline-5-sulfonic acid. D e t e c t i o n limits in t h e p p b range are achieved, a n d m a n i p u lation of electrophoretic mobilities are d e m o n s t r a t e d . David F. Swaile and Michael J . Sepaniak*, Department of Chemistry, The University of Tennessee, Knoxville, TN 37996-1600
Technical Notes
Microwave-lnduced-Plasma Reflected-Power Detector for Gas Chromatography 159
Sample Tube for Medium-Pressure Nuclear Magnetic Resonance Spectroscopy in Liquid Xenon Solution
A significant change in t h e m a g n i t u d e of t h e reflected power of t h e m i c r o w a v e - i n d u c e d - p l a s m a system results from t h e i n t e r a c t i o n of t h e p l a s m a with an a n a l y t e . T h e p o t e n t i a l usefulness of this p h e n o m e n o n as a m e a n s of detection for G C is r e p o r t e d . Rosa M. Alvarez Bolainez and Charles B. Boss*, Department of Chemistry, North Carolina State University, Box 8204, Raleigh, NC 27695-8204
Leslie D. Field*, Adrian V. George, B a r b a r a A. Messerle, and Howard Ionn, Department of Organic Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
Effect of the Source/Absorber Width Ratio on the Signal-toNoise Ratio of Dispersive Absorption Spectrometry 164 A signal-to-noise r a t i o m o d e l for a b s o r p t i o n s p e c t r o m e t r y p r e d i c t s t h a t in some cases i m p r o v e d d e t e c t i o n limits can be o b t a i n e d w h e n t h e s p e c t r a l w i d t h of t h e light source is comp a r a b l e to t h e a b s o r p t i o n s p e c t r a l w i d t h , r a t h e r t h a n m u c h less t h a n t h e a b s o r p t i o n line w i d t h as is required for a d h e r ence t o B e e r ' s law. Thomas C. O'Haver, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742
184
Determination of Dimethyl Sulfoxide and Dimethyl Sulfone in Air 186 Russell F. Lang*, Cooperative Institute for Marine and Atmospheric Studies, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 and Cheryl J . Brown, NOAA/AOML Ocean Chemistry Division, 4301 Rickenbacker Causeway, Miami, FL 33149
End-Column Detection for Capillary Zone Electrophoresis 189 Xiaohua Huang and R i c h a r d N. Zare*, Department of Chemistry, Stanford University, Stanford, CA 94305-5080 and S a n d r a Sloss and Andrew G. Ewing*, Department of Chemistry, The Pennsylvania State University, University Park, PA 16801
Luminescence Properties of Benzo[/]quinoline Adsorbed on /3-Cyclodextrin/Sodium Chloride as a Function of Temperature 169 Fluorescence a n d p h o s p h o r e s c e n c e q u a n t u m yields, p h o s phorescence lifetimes, a n d l u m i n e s c e n c e polarization d a t a reveal several i n t e r a c t i o n s for benzo[/]quinoline on /3-cyclod e x t r i n / s o d i u m chloride solid m a t r i c e s . M a r s h a D. Richmond and Robert J . Hurtubise*, Chemistry Department, University of Wyoming, Laramie, WY 82071
Use of a Single-Quadrupole Mass Spectrometer for CollisionInduced Dissociation Studies of Multiply Charged Peptide Ions Produced by Electrospray Ionization 174 M u l t i p l y charged p e p t i d e molecule ions p r o d u c e d by elect r o s p r a y ionization are collisionally a c t i v a t e d between t h e capillary exit a n d t h e s k i m m e r e n t r a n c e to t h e q u a d r u p o l e m a s s analyzer. H i g h - q u a l i t y collision-induced dissociation s p e c t r a can be o b t a i n e d from p u r e p e p t i d e s to provide prim a r y s e q u e n c e information. Viswanatham Katta, Swapan K. Chowdhury, and B r i a n T. Chait*, Rockefeller University, New York, NY 10021
52 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 2, JANUARY 15, 1991
