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  • 1
    Electronic Resource
    Electronic Resource
    The Use of Non-Splitting Injection Techniques for Trace Analysis in Narrow-Bore Capillary Gas Chromatography (1998)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 21 (1998), S. 491-497 
    Details
    ISSN: 0935-6304
    Keywords: Fast GC ; narrow-bore columns ; trace analysis ; splitless injection ; on-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The use of hot splitless, cold splitless, and on-column injections for trace analysis in narrow-bore capillary GC is evaluated. Despite the low flow rates for the columns used, the required splitless times for splitless injections can be surprisingly short if liners with a small inside diameter are used. On-column injection can be applied by using an appropriate normal-bore precolumn coupled to the narrow-bore analytical column using a specially designed low dead volume column connector. The effects of the experimental conditions such as sample volume, injection temperature, and initial oven temperature on peak focusing and the discrimination and degradation behavior of the analytes are discussed. The possibilities to obtain sensitive and fast separations are illustrated by various applications.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Possibilities and Limitations of Fast Temperature Programming as a Route towards Fast GC (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 509-513 
    Details
    ISSN: 0935-6304
    Keywords: Fast GC ; fast temperature programming ; resistive heating techniques ; short columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---One possible way to speed up a gas chromatographic analysis is the application of fast temperature programming by using resistive heating techniques. With this heating technique programming rates up to 20° per second can be reached. A relative standard deviation of retention times better than 0.2% is obtained. Using fast temperature programming the analysis-times of a mineral oil sample, an industrial oligomer sample, and toxic compounds in diesel fuel have been reduced 5 to 20 times, compared to a standard temperature programmed analysis. In most cases resistive heating cannot be applied to reduce the analysis time of a complex sample. The use of fast temperature programming is preferable to the use of short columns and columns operated at above-optimum carrier gas velocities.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Determination of sulfur components in natural gas: A review (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 373-389 
    Details
    ISSN: 0935-6304
    Keywords: GC ; Natural gas analysis ; Sulfur components ; Selective enrighment ; Sulfur selective detection ; Calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: More stringent environmental regulations as well as higher demands presently being imposed on the sulfur content of natural gas feed-stocks for chemical processes necessitate the development of new analytical procedures for sulfur determination in natural gas. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. The complexity of the natural gas matrix as well as the extremely low concentration levels at which the sulfur species occur make the development of these analytical methods a true challenge. In this review the three steps common for analytical methods for trace analysis in complex matrices, i.e. pretreatment, chromatographic separation, and detection, are discussed in detail. Possible methods for calibration of the system are discussed in the final section.Various techniques to determine sulfur in natural gas are described. Depending on the application, the most suitable system has to be selected. For example, for on-line application in a hazardous area a simple and rugged system is required, i.e. a simple gas chromatograph with a flame photometric detector, while for laboratory application a more complex instrument including preconcentration, column switching, and more exotic detection systems could be more suitable. Therefore it is crucial to define the requirements of the instrument at an early stage and use the information in this review article to develop/select a dedicated instrument/procedure for the problem at hand.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240170603
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Use of a temperature programmed injector with a packed liner for direct water analysis and on-line reversed phase LC-GC (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 459-463 
    Details
    ISSN: 0935-6304
    Keywords: LC-GC ; Aqueous samples ; Large volume injection ; PTV injector ; Solid-phase extraction ; Thermal desorption ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A system is described that allows the introduction of large volumes of water samples in capillary GC. Water elimination is carried out in the solvent split mode in a PTV injector with a packed liner. Two ways of separating water and analytes, i.e. evaporative and non-evaporative (solid-phase extraction), are compared. Sampling in the solid-phase extraction mode is favorable both in terms of recovery as well as with regard to sampling time. Quantitative recovery is obtained for priority pollutants ranging in volatility from dimethyl-phenol to phenanthrene. Losses occur for more volatile compounds, but even for these compounds the repeatability of the recoveries remains acceptable. With the system described here, water samples up to at least 1 ml of water can be directly analyzed. The detection limits are in the sub-ppb range.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160803
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Evaluation of the performance of various universal and selective detectors for sulfur determination in natural gas (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 333-342 
    Details
    ISSN: 0935-6304
    Keywords: Natural gas analysis ; Sulfur components ; Sulfur selective detection ; Universal detectors ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the present contribution, the performance of a number of commercially available selective and universal detectors that can be used in the analysis of sulfur components in natural gas is evaluated in terms of sensitivity, selectivity, reproducibility, quenching effect, stability, and compound dependence of the sulfur response. Investigated detectors include the sulfur chemiluminescnce, the flame photometric, the electron capture, the mass spectrometric, the thermal conductivity, and the flame ionization detector. The sulfur chemiluminescence detector was found to have the best overall performance, e.g., low picogram amounts of sulfur can be detected accurately and the linear dynamic range is more than five orders of magnitude. After careful optimization, the sulfur response of this detector was found to be almost compound independent. All other detectors, including the flame photometric and the electron capture detector, have more or less compound dependent responses.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180603
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    Paper (German National Licenses)
    Fulltext
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