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  • Electronic Resource  (5)
  • 1985-1989  (5)
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  • Electronic Resource  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Environmental science & technology 21 (1987), S. 541-545 
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 331 (1988), S. 253-259 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The aim of this work was: 1) to get information on the applicability of different analytical methods for the determination of P and P species, 2) to supply a general view of the concentration ranges of P in some of the major rivers of the Federal Republic of Germany. About 170 river samples have been analysed for dissolved (〈0.45 Μm) species. The methods applied were the photometric determination of o-HPO 4 2− as molybdophosphate, the determination of o-HPO 4 2− by means of ion chromatography and the P determination by inductively coupled plasma spectrometry. In addition, digestion of the samples was used before the simultaneous application of the methods to control the results. In order to get some insight into the kind of P compounds present in surface waters, sorption on polystyrene was used. All methods applied led to data of acceptable precision and turned out to be well suited for the concentration ranges present in rivers. Dissolved total P (PT) was between 0.1 and 1 mg/l in all cases. About 50 to 70% of pT was present as o-HPO 4 2− (Po-P). The fraction bound to humic matter was mostly less than 1% of PT. In case of the river Rhine the concentration of PT and Po-P increased along its course. In the Danube there seems to be a reverse tendency. The rivers Ruhr, Main and Neckar and especially the Emscher, which all contribute to the river Rhine, show significantly higher concentrations. There seems to be a concentration minimum during the summer months in the river Rhine. Further application of speciation methods in combination with hydraulic data can lead to a more detailed understanding of the fate of P compounds in river systems and to valid P balances.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 325 (1986), S. 68-72 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The fluorescence of humic substances (HUS) is quenched by paramagnetic metal ions. This principle was applied to the titration of aquatic HUS with copper(II) under defined reaction conditions (pH 6.8). For the assumption of 1∶1 complex formation conditional stability constants (K′) were determined. Stability spectra are introduced to show the influence of the ligand to metal ratio onK′. For isolated brown-water HUSK′ values range from 2 × 106 to 105 for high and low ligand to metal ratios, respectively. The structure of the stability spectra depends on the origin and kind of the HUS.
    Notes: Zusammenfassung Die Fluorescenz von Huminstoffen (HUS) wird durch paramagnetische Metallionen gelöscht. Dieses Prinzip wurde auf die Titration isolierter aquatischer HUS mit Kupfer(II) unter definierten Reaktionsbedingungen (pH 6,8) angewandt. Für den Fall einer 1∶1-Komplexbildung wurden konditioneile Gleichgewichtskonstanten (K′) bestimmt. Ihre Abhängigkeit vom Beladungsgrad der HUS mit Cu wird in sogenannten Gleichgewichtsspektren dargestellt. Sie reichen für Braunwasser-HUS vonK′ = 2 × 106 bei schwacher Beladung bis zuK′ = 105 bei starker Beladung. Die Form der Gleichgewichtsspektren ist vom Ursprung und von der Art der HUS abhängig.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 327 (1987), S. 149-153 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Use of activated carbon plays a significant role in water technology and analytical chemistry. Therefore determination of substances adsorbed on activated carbon is of special interest. As an example, granulated activated carbon (GAC) from a water treatment plant was serially extracted with different organic solvents. Quantitative determination of some selected compounds in the combined extracts was done by gas chromatography/mass spectrometry. The method of internal standard addition and calibration by response factors was used. The determined compounds (all of substituted benzene type) were extracted from the GAC in the concentration range from 0.2 mg/100 g (m-dichlorobenzene) to 5 mg/100 g (nitrobenzene). Relative standard deviation for double determination of five independent samples from the GAC filter was less than ±20% Spike experiments were performed to determine recovery efficiences. As expected, substance specific differences appeared and the recoveries were between 36% (m-dichlorobenzene) and 80% (nitrobenzene). A significant limitation for quantitative determination results from lack of available substances for calibration.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 335 (1989), S. 927-930 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The fulvic acid (FA) fractions of humic substances from river water and bog lakes and of humic-like substances from landfill leachates were isolated by the XAD-method and titrated by a cationic polyelectrolyte. The isoelectric point of net charge of the FA samples was calculated by the streaming current detection (SCD)-technique and a new parameter of charge density (aPC) was calculated from the titer volume. The aPC-values of the FA are low for humic like substances (0.22–1.76 μeq/mg DOC) and high (2.41–5.60 μeq/mg DOC) for humic substances. Polarographically determined Cu(II)-complexation capacities (CuCC) of humic-like substances are in good linear relationship to their aPC-values. Even though SCD-signals only supply qualitative information, a useful fingerprint of the FA sample is given by the shape of the titration curve.
    Type of Medium: Electronic Resource
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