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  • 1
    Electronic Resource
    Electronic Resource
    Superior ECD Performance through Design and Application (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 24-28 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; ECD ; Micro-ECD ; GC detector ; organochlorine pesticides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new ECD, the HP 6890 Series Micro-ECD, was designed to address inherent deficiencies in classical electron capture detectors (ECD), especially with respect to sensitivity, linearity, dynamic range, and ruggedness. Several novel technologies were incorporated in the totally new design and were refined through practical testing and user feedback. Validation of the micro-ECD performance was accomplished through side-by-side testing of the Micro-ECD with previous ECDs following US EPA Contract Laboratory Program methods for pesticides and PCBs. In addition, extensive interviews were conducted with early users of the Micro-ECD who also had experience with other designs running a variety of ECD methods. The design and resulting performance improvements are described.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    A study of single compound additives to minimize the matrix induced chromatographic response enhancement observed in the gas chromatography of pesticide residues (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 501-503 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Vaporizing injectors ; Matrix effects ; Organophosphorus pesticide residues ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160812
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  • 3
    Electronic Resource
    Electronic Resource
    Investigation into the GC separation of enantiomers on a trifluoroacetylated cyclodextrin. Part II: Effect of derivatization on stereoselectivity towards alcohols (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 530-535 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Resolution of enantiomers ; Stereoselectivity ; Chiral stationary phase ; Derivatized cyclodextrin ; Trifluoroacetylated cyclodextrin ; Thermodynamic properties ; Derivatization ; Alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two acyl and three fluoroacyl derivatives of 32 chiral alcohols have been chromatographed on a GC column coated with octakis(2,6-di-O-n-pentyl-3-O-trifluoroacetyl)- γ-cyclodextrin. Significant differences were observed between the stereoselectivity obtained for the derivatives and that for the underivatized alcohols. Of the derivatives, only the fluoroacylated compounds were separated into enantiomers. Derivatization with fluoroacyl groups reversed the elution order for at least some of the analytes. Stereoselectivity towards simple 2- and 3-hydroxy alkanes and their fluoroacyl derivatives was highest for those alcohols with a four-carbon chain attached to the stereogenic center. For longer-chain fluoroacyl derivative groups stereoselectivity was higher for the 2- and 3-hydroxy alkanes. Differences in stereoselectivity towards alcohols with a methyl-branched alkane chain and their fluoroacyl derivatives was related to the distance between the methyl group and the hydroxyl or fluoroacyl groups. Different degrees of saturation in the carbon chain resulted in differences in stereoselectivity. Thermodynamic data calculated for a number of analytes suggest that the alcohols and trifluoroacetate derivatives are interacting with the stationary phase by similar mechanisms. The stereospecific interaction appears to have a hydrogen bonding or dipole-dipole contribution and some form of steric component, depending upon the shape and/or size of the solute.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160906
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  • 4
    Electronic Resource
    Electronic Resource
    Intra- and intermolecular interactions in the first members of homologous series of carbonyl containing compounds in gas chromatography (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 47-51 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns, glass ; Packed columns ; Free energy of sorption ; Intramolecular interactions ; Intermolecular interactions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Variation of the values of free energy of sorption of the methylene unit has been studied in the homologous series of n-alkyl methyl ketones, n-alkyl butyl ketones, n-alkyl acetates, and methyl esters of carboxylic acids, depending on the homologue number and the temperature of analysis. The experiment was carried out on a capillary column with a thick film of immobilized Silicone SE-54 and on packed columns with OV-210 and Silar-10C. An intramolecular donor-acceptor interaction between neighboring CH3— and C=O groups is assumed to be the reason for anomalously high values of free energy of sorption of the first CH2 unit in the series: RmC(O)OCH3, RmC(O)CH3, and RmC(O)C4H9. The anomaly disappeared in stationary phases containing strongly electronegative —CF3 and —CN groups because of specific inter molecular interactions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130110
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  • 5
    Electronic Resource
    Electronic Resource
    Fused silica substrate effects on capillary column performance (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 348-351 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fushed silica capillary columns ; Surface properties ; 50% phenyl stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of a pretreatment step on the polarity of fused silica capillary tubing prior to coating was evaluated. Columns were tested prior to and after coating with a 50% phenl stationary phase, and the chromatographic findings were compared. The results confirmed that the polarity of the fused silica substrate affects the inertness and reproducibility of the final coated columns.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130511
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  • 6
    Electronic Resource
    Electronic Resource
    A polymeric liquid crystal capillary column for GC-MS analysis of PCDD and PCDF (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 143-146 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Polymeric liquid crystal stationary phase ; Polysiloxane ; PCDD ; PCDF ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A newly developed side chain liquid crystal polysiloxane has been investigated as a stationary phase for the isomer-specific analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans substituted at positions 2, 3, 7, and 8. The retention times from the chromatograms of a standard solution containing all PCDD and PCDF isomers were compared with those from solutions containing only those tetra- to octa-chlorinated compounds substituted at positions 2, 3, 7, and 8. In general, PCDDs substituted at positions 2, 3, 7, and 8 eluted later than most other isomers of the same congener group. The separations obtained on this stationary phase were compared with those obtained elsewhere using a commercially available product.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140217
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  • 7
    Electronic Resource
    Electronic Resource
    Unified gas and supercritical fluid chromatography on 50 μm i.d. Columns (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 505-509 
    Details
    ISSN: 0935-6304
    Keywords: Unified chromatography ; Gas chromatography ; Supercritical fluid chromatography ; Open tubular column ; Injection technique ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A unified approach to sequential gas and supercritical fluid Chromatography using 50 μm i.d. open tubular columns is described. Sample introduction is performed by means of a rotary injection valve. In order that linear velocities can be optimized independently, a second rotary valve in the chromatographic oven is used to direct the flow of column eluate to the flame ionization detector through either fused silica tubing in GC, or a frit restrictor in SFC.Applications of sequential GC-SFC on a 50 μm i.d. open tubular column are demonstrated, and comparisons made between sequential GC-SFC on 50 and 100 μm i.d. columns.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150804
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of amino acids in the hepatic and brain tissue of the rat by gas chromatography (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 579-583 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary column ; Cold on-column injection ; Amino acid analysis ; Liver ; Brain ; Rat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure is described for the quantitative determination of amino acids in hepatic and brain tissue samples from the rat. Because the presence of certain matrix components in the tissue material led to interference with chromatographic analysis they were removed by a prechromatographic “clean-up” step.Quantitative analysis of amino acids, as their N-heptafluorobutyryl iso-butyl ester derivatives, was achieved by high resolution gas chromatography on an apolar fused silica open tubular column. Reproducibility data from the complete procedure are presented; coefficients of variation for arginine and histidine in hepatic tissue varied between 7.1 and 10.1% whereas those for most other amino acids were better than 5%, with a mean recovery of 90%.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140903
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  • 9
    Electronic Resource
    Electronic Resource
    Investigation into the GC separation of enantiomers on a trifluoroacetylated cyclodextrin. I. Effect of analyte structure on stereoselectivity for alcohols (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 800-806 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Resolution of enantiomers ; Chiral stationary phase ; Derivatized cyclodextrin ; Trifluoroacetylated cyclodextrin ; Structural effects ; Thermodynamic properties ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: More than 30 enantiomeric alcohols have been analyzed, without prior derivatization, by gas chromatography using a fused silica capillary column coated with octakis(3-O-trifluoro-acetyl-2,6-di-O-n-pentyl)-γ-cyclodextrin. Most were analyzed over a range of isothermal temperatures from 35 to 70°C. Enantiomeric separations were observed for most of the analytes, even at temperatures as low as 35°C.The stereoselectivity of the stationary phase was found to depend on the length of the longest carbon chain attached to the stereogenic centre in 2- and 3-hydroxy alkanes, the relative positions of the methyl and hydroxyl substituents in methylsubstituted alcohols, and the effects of multiple bonds in the analyte molecule. Thermodynamic data calculated from the results suggest that the enantiomers of all the analytes are resolved by a similar process. Retention and thermodynamic data are presented and possible mechanisms discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240151206
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  • 10
    Electronic Resource
    Electronic Resource
    Chromatography of organic derivatives of group IVB elements (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 4 (1990), S. 77-89 
    Details
    ISSN: 0268-2605
    Keywords: Gas chromatography ; liquid chromatography ; Group IV ; detectors ; separation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatographic aspects of the analysis of Group IV organometallic derivatives are reviewed. The emphasis is towards gas and liquid chromatography.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590040202
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