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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 174 (1954), S. 974-974 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Nevertheless, in the Netherlands some successful attempts have been made to obtain information by other methods. Thus examination of urine has been shown to offer an insight into the ingestion of potassium, sodium, chlorine and sulphate by cows at pasture or stall-fed1. Information about iodine ...
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Respiratory occupational exposure to the Z- and E-isomers of 1,3-dichIoropropene (DCP)2 of twelve commercial applicators was assessed. The time-weighted average (TWA) concentrations of DCP ranged from 1.9 to 18.9 mg/m3. On 30% of the observed working days the Dutch occupational exposure limit of 5 mg/m3 was exceeded. Short-term exposure levels during tank-loading and repair were up to 30 mg/m3. Emission of dichloropropene during the injection process has a major impact on the TWA concentration. Modification of the injection system may reduce the concentration of DCP substantially.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract A biological monitoring study was carried out in the Dutch flower-bulb culture to determine the relationship between respiratory occupational exposure to Z- and E-1,3-dichloropropene (Z- and E-DCP) and urinary excretion of two mercapturic acid metabolites, N-acetyl-S-(Z- and E-3-chloropropenyl-2)-L-cysteine (Z- and E-DCP-MA). Urinary excretion of Z- and E-DCP-MA, either based on excretion rates or on creatinine excretion, followed first order elimination kinetics after exposure. Urinary half-lives of elimination were 5.0 ± 1.2 hr for Z-DCP-MA and 4.7 ± 1.3 hr for E-DCP-MA and were not statistically significantly different. Calculated coefficients of variation indicated that the half-lives of elimination of Z- and E-DCP-MA were quite consistent inter- and intra-individually. Strong correlations (r ⩾ 0.93) were observed between respiratory 8-hr time weighted average (TWA) exposure to Z-and E-DCP and complete cumulative urinary excretion of Z- and E-DCP-MA. Z-DCP yielded three times more mercapturic acid than E-DCP, probably due to differences in metabolism. Z- and E-DCP were excreted 45 and 14% as their respective mercapturic acid metabolites. A respiratory 8-hr TWA exposure to the Dutch occupational exposure limit of 5 mg · m−3 DCP would result in a complete cumulative excretion of 14.4 mg (95% confidence interval: 11.7–17.0 mg) Z-DCP-MA and 3.2 mg (95% confidence interval: 2.3–4.1 mg) E-DCP-MA.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A liquid chromatographic method using gradient elution and diode array UV detection for the trace level determination of seven synthetic pyrethroids is described. The procedure involves automated on-line preconcentration on precolumns containing octadecylbonded silica using a Prospekt. Although the analytes display a “mixed” hydrophobic/hydrophilic behaviour, both breakthrough on the precolumn and adsorption to inner walls and surfaces can be prevented by adding Brij-35, a neutral surfactant, to the aqueous sample. The procedure has been tested for the analysis of surface water; detection limits typically are at the sub-μg/l level and repeatability is excellent. The automated system is robust and there are no maintenance problems.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Membrane-extraction disks ; On-line trace enrichment ; Polar pollutants ; Surface water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An on-line trace-enrichment system, using a bifunctional membrane extraction-disk cartridge, has been combined with a column liquid chromatography separation for the simultaneous determination of basic, neutral and acidic pollutants in surface water. The enrichment device consisted of a specially constructed holder containing both C-18 and cation-exchange disks. The holder can contain up to 25 disks of 0.5 mm thickness and 4.6 mm diameter. Before trace enrichment of 20 ml of surface water (pH 3.0), calcium ions were removed from the sample by means of an oxalic acid precipitation. Desorption of the cartridge was at elevated temperature using reversed-phase gradient elution; detection was performed with a diode-array UV absorbance detector. The detection limits for the test compounds in surface water are typically 0.5–2 μg/l; the calibration graphs are linear from the lower limit of determination up to 50 μg/l.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report describes two hypogammglobulinemic patients with persistentCampylobacter jejuni infections in spite of IgG substitution and antibiotic therapy. Since serum bactericidal activity (SBA) depends on IgM, these patients were each treated with six doses of an IgM-containing immunoglobulin preparation (Pentaglobin) at three-week intervals. During IgG therapy SBA was not seen in either patient. However, one hour following administration of the IgM preparation SBA increased to 90 %. Just before the next dose SBA was still at the 30–70 % level. Both patients tolerated the therapy very well and there were no culture-confirmed relapses ofCampylobacter jejuni infection. The IgM preparation may therefore be a useful alternative to conventional IgG in the treatment of hypogammaglobulinemic patients with persistentCampylobacter jejuni infection.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; On-line preconcentration ; Polar pollutants ; Water (tap and surface)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An isocratic column liquid chromatographic system with UV absorbance detection at 230 nm has been developed for the rapid trace-level determination of a large number of polar pollutants in water. The systems contains two precolumns, in series, which are packed with a styrenedivinylbenzene (PLRP-S) polymer. The second precolumn is also loaded with sodium dodecylsulphate before use. Each precolumn is combined with a PLRP-S analytical column, and aqueous acetonitrile mixtures (pH 3) are used for the separation of neutral as well as acidic and basic pollutants. With 10-ml water samples the detection limits for all analytes, in tap water, are in the low to sub μg/l range. Relevant analytical data are reported and the advantage of using a dodecylsulphate-loaded precolumn over a cation-exchange precolumn is discussed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polar pollutants in water ; On-line trace enrichment ; Humic substances
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A practical liquid chromatographic early-warning system for polar pollutants in water ought to have detection limits at a level below a microgram per litre. Using ultraviolet absorbance detection this normally necessitates trace enrichment of the samples. In this study ten different sorbents have been tested with respect to their enrichment capacity. The hydrophobic polymeric PLRP-S material, in combination with a C-18 modified analytical column, proved to be the best choice. The influence of humic substances, present in surface water, was also studied. Lowering of the sample pH, resulted in a significant increase in the interferences due to the humic substances.
    Type of Medium: Electronic Resource
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  • 9
    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
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