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  • Gas chromatography  (21)
  • Gas Chromatography  (9)
  • Capillary GC  (7)
  • Solvent effects  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Preparation of apolar glass capillary columns by the barium carbonate procedure (1978)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 149-155 
    Details
    ISSN: 0935-6304
    Keywords: Gas Chromatography ; Capillary, glass ; Preparation of apolar columns ; Ba CO3 procedure optimized for thermostability acid/base behaviour and efficiency ; New, quantitative testing procedure ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As an extension of previous reports, the barium carbonate procedure has been optimized in detail for the preparation of apolar columns. The aim was to produce optimum overall column characteristics, and to maintain them unchanged under the prolonged influence of the highest possible temperature. The main parameters under optimization were glass variety, leaching of glass surface with aqueous HCl, and amount of barium carbonate deposited, while deactivation and coating were kept constant. The basic column characteristics were adsorption properties and thermostability of deactivation, acid/base behaviour and separation efficiency. They were determined by a new, quantitative testing procedure. Intense leaching was able to eliminate almost totally the differences between glass varieties and to create a well-defined glass surface. While untreated glass, leached glass, and barium carbonate treated glass showed specific weak points in the respective column quality, the combination of leaching and barium carbonate treatment yielded the highest and most stable quality. Some technical modifications of the preparation procedure are described, including deactivation in the gas phase, and use of pentane as a solvent for static coating.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240010306
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  • 2
    Electronic Resource
    Electronic Resource
    Deactivation of glass capillaries by persilylationThe term persilylation denotes complete silylation, in contrast to partial silylation achieved by common procedures.. Part 2: Practical recommendations (1979)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 2 (1979), S. 677-678 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Surface deactivation, persllylation ; Discussion of variable parameters ; Suggested practical procedure ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240021110
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  • 3
    Electronic Resource
    Electronic Resource
    Deactivation of glass capillary columns by silylation. Part 1: Principles and basic technique (1979)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 2 (1979), S. 31-35 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Surface deactivation, silylation ; Inertia stable to 350° ; Free acids and bases, simultaneous injection ; On-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A deactivation procedure is described based on a published method using hexamethyldisilazane in the gas phase. In addition to unusually high inertia and thermostability, the method produces truly neutral columns which allow simultaneous analysis of moderately strong free acids and bases. The silylated columns show their full potential only with on-column injection. Preliminary experimental directions are given; more elaborate directions will become available after extended optimization work.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240020110
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  • 4
    Electronic Resource
    Electronic Resource
    Splitless injection and the solvent effect (1978)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 57-64 
    Details
    ISSN: 0935-6304
    Keywords: Gas Chromatography ; Capillary, glass ; Splitless injection, basis of ; Use for any sample ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Splitless injection is based on the solvent effect as a mechanism condensing large vapour clouds down to infinitely shortened bands. The effect is controlled by the parameters column temperature, volatility and amount of solvent, and rate of injection. By properly selecting the variables the effect can easily be optimized for any combination of sample and column. It is the purpose of this paper to provide the mechanistic understanding as required for this optimization, as well as some rules for the experimental realization. Potentialities and limitations of splitless injection are discussed, and the role of the solvent effect in on-column injection is emphasized.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240010112
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  • 5
    Electronic Resource
    Electronic Resource
    Broadening of peaks eluted before the solvent in capillary GC Part 1: The role of solvent trapping (1983)
    Springer
    Chromatographia 17 (1983), S. 357-360 
    Details
    ISSN: 1612-1112
    Keywords: Capillary GC ; Peak deformation ; Solvent trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In capillary GC the analysis of solutes eluted before the solvent is often precluded because of severe broadening and distortion of the peaks. This problem has three sources: a) most solutes are partially solvent trapped; b) phase soaking broadens peaks eluted shortly before the solvent and c) slow sample transfer from the injector to the column in splitless injection creates broad initial bands which cannot be re-concentrated to narrow bands. The most important (and troublesome) broadening effect is partial solvent trapping. Full solvent trapping of solutes eluted before the solvent only occurs under special conditions. Most solutes are either partially trapped or non-trapped. Partial solvent trapping is mostly of the weak type, broadening the solute bands less than that due to the evaporation time of the solvent at the column inlet. Deformation of peaks eluted before the solvent by solvent trapping can only be avoided by the selection of conditions which create non-trapping. Rapid introduction of the sample into the column is required, which calls for split or on-column injection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262372
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  • 6
    Electronic Resource
    Electronic Resource
    Broadening of peaks eluted before the solvent in capillary GC Part II: The role of phase soaking (1983)
    Springer
    Chromatographia 17 (1983), S. 361-367 
    Details
    ISSN: 1612-1112
    Keywords: Capillary GC ; Peak deformation ; Phase soaking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Phase soaking is a solvent effect which tends to reconcentrate peaks eluted after and to broaden peaks eluted before the solvent. The principles of the phase soaking effect on peaks eluted before the solvent are discussed. The broadening effect is distinguished from the broadening effect occurring in the flooded column inlet by partial solvent trapping. It was found that in most cases broadening by partial solvent trapping strongly predominated over broadening by phase soaking. Phase soaking was noticeable only in the neighbourhood of the solvent peak. Phase soaking does not broaden peaks eluted before the solvent as much as it re-concentrates those eluted after it. The two phase soaking effects on the front and the rear of the solvent band (that is, of the soaked zone) differ strongly from each other. Peak broadening by phase soaking is negligible for non-trapped components, because such solutes start their chromatography before a significant quantity of solvent enters the column. Phase soaking only broadens solute bands which were retained by the solvent in the column inlet, that is, bands already broadened by partial solvent trapping.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262373
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  • 7
    Electronic Resource
    Electronic Resource
    Co-injections to avoid peak distortion due to partial solvent trapping in capillary gas chromatography (GC) (1984)
    Springer
    Chromatographia 18 (1984), S. 197-201 
    Details
    ISSN: 1612-1112
    Keywords: Capillary GC ; Co-injection ; Solvent effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Co-injection techniques (introducing additional pure solvent with the sample) were tested to eliminate peak distortion due to partial solvent trapping. Co-injections of solvent identical with the sample solvent were not successful, because first only partial solvent trapping of the strong type could be eliminated and second, there was no practicable method of placing a band of pure solvent ahead of the sample in the column inlet. Successful co-injections have to accept mixing of the sample with the pure solvent. Either the solvent trapping is improved by co-injection of a solvent which enhances solution of the critical solutes in the sample layer, or it creates a phase soaking effect in the stationary phase and reconcentrates broadened bands beyond the flooded inlet. The added solvent must have the appropriate polarity and some of it must remain in the column inlet at least until the sample solvent has completely evaporated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02276732
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  • 8
    Electronic Resource
    Electronic Resource
    Glass wool in the injector insert for quantitative analysis in splitless injection (1984)
    Springer
    Chromatographia 18 (1984), S. 517-519 
    Details
    ISSN: 1612-1112
    Keywords: Capillary GC ; Matrix effect in splitless injection ; Glass wool in injector insert
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use is suggested of a light packing of (silylated) glass wool in the injector insert between the end of the inserted syringe needle and the column inlet to improve quantitation in splitless injection for samples containing some involatile material. Glass wool reduces the standard deviation of the results but its major advantage is the improvment of the solute transfer onto the column. It reduces or eliminates “matrix effects” in splitless injection where solute transfer, and hence absolute and relative peak areas, depends on the sample composition (a source of serious systematic errors). High injector temperatures are required to overcome the retention of the solutes in the sample byproducts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02267238
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  • 9
    Electronic Resource
    Electronic Resource
    Static coating of glass capillary columns. Solvent selection; Column filling; Solvent evaporation (1978)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 93-94 
    Details
    ISSN: 0935-6304
    Keywords: Gas Chromatography ; Capillary, glass ; Static coating, apolar gums ; Pentane better than methylene chloride, ready in 8 hours ; (20 m, 0.3 mm i.d.) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240010204
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  • 10
    Electronic Resource
    Electronic Resource
    Separation of monounsaturated fatty acid methyl esters by capillary GLC? (1978)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 94-95 
    Details
    ISSN: 0935-6304
    Keywords: Gas Chromatography ; Capillary, glass ; Quantitative analysis of unsaturated fatty methyl esters ; Remarkable systematic errors of cis/trans determination ; Errors depend on phases chosen ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240010205
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