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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
    Determination of triazine herbicides in surface and drinking waters by off-line combination of liquid chromatography and gas chromatography-mass spectrometry (1992)
    Springer
    Chromatographia 34 (1992), S. 5-13 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography-mass spectrometry ; Water analysis ; Triazine herbicides ; Chemical ionization mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Mass spectra of 12 triazines were obtained by electron impact (EI), positive-ion chemical ionization (PCI) and negative-ion chemical ionization (NCI) using methane and isobutane as reagent gases. EI mass spectrometry is more sensitive than PCI and NCI, although the chemical ionization modes increase selectivity markedly. A pre-column packed with polymer stationary phase was employed to preconcentrate surface and drinking water samples. After desorption of the analytes with ethyl acetate, an aliquot was injected directly into the GC-MS system. Atrazine and simizine were found in these samples at 10–80 ppt levels. The limits of detection for both herbicides were below 10 ppt in drinking water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290451
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Use of membrane extraction disks for on-line trace enrichment of organic compounds from aqueous samples (1990)
    Springer
    Chromatographia 29 (1990), S. 415-418 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Trace enrichment ; Membrane extraction disks ; Triazine herbicides ; 2,3,4-Trichlorophenol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Membrane extraction disks have been recently introduced for the solid-phase extraction of organic compounds from aqueous samples. The material consists of alkyl-modified silica particles enmeshed in an inert PTEE matrix. Aqueous samples containing polar pesticides and herbicides, are preconcentrated on-line from acidic solutions on membrane extraction disks containing immobilized octadecyl-modified silica and analyzed with an isocratic liquid chromatographic system using PLRP-S as the stationary phase and aqueous acetonitrile mixtures (pH 3) as the eluent. Data on the lifetime and the dimensions of the preconcentration disks, and the efficiency and the repeatability of the procedure are reported. For 10 ml samples, the detection limits of the analytes atrazine, simazine and 2,3,4-trichlorophenol in tap water are 0.1–1 ppb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261387
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    Paper (German National Licenses)
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  • 4
    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
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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