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  • 1
    Electronic Resource
    Electronic Resource
    Electrodialytic sample treatment coupled on-line with high-performance liquid chromatography (1990)
    Springer
    Chromatographia 30 (1990), S. 361-366 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Electrodialytic sample treatment ; On-line coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An electrodialytic sample treatment method coupled on-line with high-performance liquid chromatography (EDIST-HPLC) is discussed in this paper. The performance of EDIST as a function of the donor-phase (sample solution) flow rate, the voltage applied over the electrodialysis block, and the time of dialysis has been studied using the basic drug ephedrine as a model compound. Enrichment of the analyte by a factor of 10–20 was possible. The determination of human plasma spiked with ephedrine is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02328498
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Reversed-phase liquid chromatography coupled on-line with capillary gas chromatography use of an anion-exchange membrane to remove an ion-pair reagent from the eluent (1995)
    Springer
    Chromatographia 40 (1995), S. 267-271 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; On-line coupling ; Ion-exchange membrane ; Ion-pair reagent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In order to enable the coupling of reversed-phase liquid chromatography (RPLC) with capillary gas chromatography (GC), the performance of an anion-exchange micromembrane device has been studied to remove the ion-pair reagent methanesulphonic acid from an acetonitrile/water LC eluent. The regenerant in the membrane was tetrabutylammonium hydroxide dissolved in acetonitrile/water, which effects an anion-exchange of methanesulphonate ions for regenerant hydroxide ions. The efficiency of the exchange process was found to be 99.9%. This enabled the direct introduction of the LC eluent, free of ions and with the proper acetonitrile/water ratio, into the GC. The applicability of the on-line LC-micromembrane-GC system has been illustrated for the potential drug eltoprazine, which is quantitatively recovered with a coefficient of variation for standard solutions of 3% at the 150 μg/ml analyte level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290356
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of polychlorinated biphenyls in sediment by on-line narrow-bore column liquid chromatography/capillary gas chromatography (1988)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 11 (1988), S. 197-202 
    Details
    ISSN: 0935-6304
    Keywords: Coupling LC/GC ; Retention gap ; Polychlorinated biphenyls ; Sediment ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Narrow-bore column liquid chromatography coupled on-line with capillary gas chromatography (LC/GC) is used for the determination of polychlorinated biphenyls (PCBs) in sediment via a heart-cutting technique. This method is compared with a method in which two off-line column clean-up steps are used with subsequent analysis by capillary gas chromatography. For the LC/GC analysis the recovery of PCBs was 90-100%. For two sediment samples from the river Meuse the LC/GC and the other, more laborious method showed good agreement.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240110211
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The potential of on-line flame photometric detection in microcolumn liquid chromatography (1989)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 793-796 
    Details
    ISSN: 0935-6304
    Keywords: Microcolumn liquid chromatography ; Flame photometric detection ; Organophosphorus compounds ; On-line preconcentration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential of an interface for the on-line coupling of microcolumn liquid chromatography (LC)and a flame photometric detector (FPD) has been further investigated. With the micro-LC/FPD system, relatively high-molecular-weight polar compounds such as cyclic adenosine monophosphate, guanosine monophos- phate, glucose monophosphate, fructose monophosphate, and phytic acid were separated and selectively detected. In order to increase the sensitivity, on-line preconcentration with a microprecolumn inserted in the rotorof a Valcovalve has been applied. Preliminary results have shown that an injection volume of at least 500 1-11 water containing organophosphorus acids at a 5-50 ng/rnl concentration level is possible.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240121206
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Polar solvents for the desorption of a liquid chromatographic precolumn coupled on-line with a capillary gas chromatograph (1989)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 807-812 
    Details
    ISSN: 0935-6304
    Keywords: Polar solvents ; Coupled LC-GC ; Partially concurrent solvent evaporation ; Trace enrichment ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling column liquid chromatography and gas chromatography on-line is becoming more important in analytical chemistry. Especially when large amounts of polar solvents can be introduced into the gas chromatograph without any problem, the technique will offer new possibilities. With a DPTMDS retention gap, evaporation rates and flooded zones of some solvents have been determined. Two modes of operation using partially concurrent solvent evaporation conditions are discussed: (1) injecting a sample via a loop of an LC valve followed by introduction into the gas chromatograph with an LC pump; (2) trace enrichment on a precolumn followed by on-line desorption with n-propanol into the gas chromatograph. Preliminary results for a splitter system, inserted between the retention gap and the analytical column which allows a considerable increase of the evaporation rate are also presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240121209
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    Paper (German National Licenses)
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