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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 148-152 
    ISSN: 0935-6304
    Keywords: On-line SFE-GC ; Polychlorinated biphenyls ; Human milk ; Human blood serum ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On-line coupled supercritical fluid extraction and gas chromatography (SFE-GC) has been utilized for the determination of PCBs and other organochlorine compounds in human milk and blood serum. The procedure involved preconcentration of the sample on C18-silica sorbent in an extraction cell: after precipitation of the proteins up to 20 ml of human milk was concentrated on 0.5 g of sorbent. Serum (up to 5 ml) was applied to the C18 material without pretreatment. Basic alumina was utilized as a selective adsorbent for lipids in the on-line SFE-GC system. The method was used to analyze milk and serum spiked with 0.5 and 10 ng of Aroclor 1260 and the results compared with those obtained by liquid-liquid extraction of serum.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 49-50 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Automated injection ; Solvent venting ; 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
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 197-202 
    ISSN: 0935-6304
    Keywords: GC and GC-MS ; HPLC ; SFC ; TLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Practically all the conventional chromatographic techniques are used in the characterization of the highly complex mixtures of organic compounds occurring in fuels, heavy fractions, and crude oils. This paper surveys the techniques employed for class determination, preparative fractionation of the main classes, and determination of subgroups after class fractionation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 9-14 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Atomic emission detection ; Low-resolution monochromator ; Near-infrared region ; Non-specific responses ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A single 0.2 m focal length near-IR monochromator providing a 0.8-3.2 nm effective bandpass was evaluated as spectrometer for F-, Cl-, Br-, I-, S-, and P-selective atomic emission detection in capillary gas chromatography. With optimized plasma conditions and careful wavelength selection, interferences from eluting hydrocarbons were almost eliminated for all the elements studied (element-to-carbon selectivities between 1000:1 and 10000:1). For Cl and S, other heteroatoms were found not to cause cross-interferences. F-, Br-, I-, and P-selective detection, however, was complicated by this second type of non-specificity. For these atoms, elemental confirmation was carried out by analyzing the samples also for heteroatoms potentially causing interferences.
    Additional Material: 3 Ill.
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  • 5
    ISSN: 0935-6304
    Keywords: capillary gas chromatography ; microplasma mass spectrometry ; radio frequency plasma ; element-selective detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Capillary gas chromatography was performed with mass spectrometric detection using a novel microplasma ion source for operation in an element-selective mode. The ion source was a 350 kHz radio frequency helium plasma, which was sustained inside the 4 cm end of a 0.32 mm i.d. fused silica capillary column, and located inside the high vacuum chamber of the quadrupole mass spectrometer. Due to the low volume of the ion source, a stable low pressure discharge was produced utilizing only the 2.25 mL min-1 of GC carrier gas (helium) for plasma support. Small amounts of oxygen (0.1-0.2% v/v) were added to the plasma gas in order to prevent carbon deposits and to enhance signal-to-noise ratios. Chlorine and bromine were selectively detected at the 5-20 pg s-1 level (S/N = 2), and both produced a response that was linear within 3 orders of magnitude.
    Additional Material: 3 Ill.
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  • 6
    ISSN: 0935-6304
    Keywords: capillary gas chromatography ; microplasma mass spectrometry ; radio frequency plasma ; element-selective detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Simultaneous element-selective detection of the halogens and carbon was accomplished with capillary gas chromatography coupled with microplasma mass spectrometry. The microplasma ion source was a radio frequency plasma contained inside the last 4-5 cm of the 0.32 mm i.d. fused silica capillary column. The ion source was located inside the high vacuum housing of the MS, and only the GC carrier gas (2.3 mL min-1 of helium) was used for plasma generation. Atomic ions were detected in the positive mode. Detection limits were in the low picogram area, and the selectivity to carbon ranged from 8×102 for fluorine to higher than 104 for the other halogens. By introduction of both hydrogen and oxygen as reagent gases, peak tailing was avoided by suppression of analyte reactions with the silica walls of the ion source. Special attention was given to the fluorine-selective detection due to an interfering background species at m/z 19, assumed to be H3O+ originating from the reagent gases. The background signal was minimized by careful control of the power level.
    Additional Material: 5 Ill.
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  • 7
    ISSN: 0935-6304
    Keywords: Large volume injection ; packed capillary LC ; temperature programming ; retinyl esters ; vitamin A ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A non-aqueous isocratic reversed-phase packed capillary high performance liquid chromatography method for the determination of retinyl esters, utilizing temperature programming and on-column focusing large volume injection, has been developed. The stationary phase material was C30, and the mobile phase consisted of acetonitrile-dichloromethane (70 : 30, v/v). A three-step temperature program, starting at 10°C for 10 min, then 1°/min to 30°C, and finally 2.5°/min to 70°C, was found most appropriate. Compared to an isothermal separation at 25°C, this temperature program provided improved peak resolution, enhanced peak shapes of the last eluting compounds, and a reduction of the overall elution time. A mass limit of detection of 27 pg was found with respect to retinyl palmitate, using UV detection with an “U” shaped flow cell at 327 nm. This corresponds to a concentration limit of detection of 2.7 pg/μL, when utilizing an injection volume of 10 μL. The concentration of retinyl palmitate in arctic seal liver samples was estimated to be 62.6 μg/g liver.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 597-607 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Atomic emission detection ; Environmental applications ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Environmental applications of capillary gas chromatography coupled with atomic emission derection (GC-AED) have been reviewed with emphasis on both the commercial and laboratory-built systems. Attention was focused on (1) element-selective detection of non-metallic as well as metallic pollutants, (2) identification of contaminants, and (3) sample preparation considerations.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 525-530 
    ISSN: 0935-6304
    Keywords: Packed capillary liquid chromatography ; temperature programming ; Fourier-transform infrared spectroscopy ; polymer additives ; pneumatic nebulization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Temperature-programmed packed capillary liquid chromatography has been coupled off-line to Fourier-transform infrared spectroscopy, utilizing a commercially available interface with a pneumatic nebulizer rebuilt to handle low flow rates at elevated temperatures. The modified interface showed excellent performance with regard to non-aqueous reversed phase separations of polymer additives, resulting in constructed Gram-Schmidt chromatograms comparable to chromatograms obtained using UV detection. The spray of the in-house constructed nebulizer was not influenced by temperature changes of the column effluent, and hence temperature-programmed gradient separations could be used successfully. The relative standard deviation of peak height was 4.4% (n = 5) and the mass limit of detection was determined to be about 40 ng, using a polymer antioxidant as model compound. The present instrumental coupling has been used for characterization of the antioxidant Irgafos P-EPQ.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 283-286 
    ISSN: 0935-6304
    Keywords: Evaporative light scattering detection ; capillary nebulizer ; packed capillary ; columns ; high temperature liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 5 Ill.
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