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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Environmental science & technology 28 (1994), S. 1194-1197 
    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
    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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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 63 (1991), S. 2122-2130 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    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 346 (1993), S. 707-710 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chlorination of drinking water often leads to undesirable byproducts. Little is known about the hydrophilic chlorinated fragments and the high molecular products. For the investigations presented here, solutions of fulvic acids were chlorinated which had been isolated from a brown water lake and from a groundwater rich in DOC. The fulvic acid-like part of the products was reisolated using XAD-2 resin. Both the original fulvic acid and the chlorinated product were analyzed by pyrolysis in combination with gas chromatography/mass spectrometry. A number of compounds was identified including furandiones and pyrandiones. However, it remains unclear whether the furanones and pyranones were already present in the chlorinated samples or whether these were formed during pyrolysis by elimination of water from dicarboxylic acids.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 364-369 
    ISSN: 1618-2650
    Keywords: Best. von Blei, Cadmium, Kupfer, Zink in Wasser ; Voltammetrie, inverse ; Grundwasser, Leitungswasser, Vergleich mit AAS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die inverse Voltammetrie ist für Schwermetallbestimmungen in Grund- und Leitungswasser geeignet. Das wird durch die Qualitätskriterien der Werte und den Vergleich mit atomabsorptionsspektrometrischen Messungen gezeigt. Beim Grundwasser tritt die Art der Probenahme als wichtige Einflußgröße hervor. Stagniertes Wasser in Hausinstallationen zeigt bis zu 10fache Konzentrationen, verglichen mit den durch kräftiges Abfließen erreichbaren Minimalwerten. Die Wassertemperatur ist hierfür eine gute Beurteilungshilfe.
    Notes: Summary Heavy metals in ground water and tap water can be determined by differential pulse anodic stripping voltammetry (DPASV). This is shown by the quality criteria of the results and by comparison with AAS values. Concentrations down to 0.1 μg/l are detectable. The way of sampling turns out to be quite important for ground water results. Heavy metal content in tap water is influenced by the retention time in the domestic pipes. Stagnation values are up to ten times the minimum concentration measured after heavy discharge. Water temperature is shown to be a good criterion for heavy metal concentration in that case.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 316 (1983), S. 582-588 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Huminstoffe (HUS) sind in allen Gewässern vorhanden. Ihre analytische Identifizierung und Quantifizierung leidet an der mangelnden Kenntnis der Gesamtstruktur. Zur Charakterisierung der Gewässerhuminstoffe und ihrer Reaktionsfähigkeit sind daher Summen- und Gruppenparameter besonders wichtig. Eine Isolierung aus Gewässern ist für die Aussagekraft der Werte und ihre Reproduzierbarkeit wesentlich. Die Wechselwirkung mit Metallen läßt sich unter definierten Reaktionsbedingungen bestimmen und durch gezielte Modellversuche überprüfen. Unter Komplexierungskapazität (CC) ist hierbei die nach einem bestimmten Verfahren ermittelte maximale Metallbindung je Huminstoffeinheit zu verstehen. Die auf Kupfer bezogene CC wird durch Titration einer vorgelegten Cu(II)Menge (10 μmol/l) mit einer Huminstofflösung bekannter DOC-Konzentration bei einem pH-Wert von 6,8 bestimmt. Die differentielle Pulspolarographie mit einer tropfenden Quecksilberelektrode wird als Detektor verwendet. Die Ergebnisse (2 bis 7 μmol pro mg DOC) lassen für die Komplexbildung neben stickstoffhaltigen Gruppen eine Beteiligung sauerstoffhaltiger Gruppierungen vermuten. Das auch bei einem pH-Wert von 2,2 noch fest in den HUS gebundene Eisen zeigt eine gewisse Ähnlichkeit mit dem in Hydroxamsäurekomplexen gebundenen Fe(III). Die koordinative Bindung von Hg(II) and Thiogruppen der HUS kann mit Hilfe photochemischer Abbaureaktionen mit Modell-Liganden und natürlichen Proben bewiesen werden. Die für natürliche HUS bestimmten Komplexierungskapazitäten zeigen, daß in Gewässern meist mit einem Überschuß organischer Ligandfunktionen gegenüber den gelösten Schwermetallen zu rechnen ist. Komplexierungskapazitäten sollten jedoch nur im Zusammenhang mit der angewandten Bestimmungsmethode und dem jeweiligen Bezugsmetall betrachtet werden.
    Notes: Summary Humic substances (HUS) are present in all aquatic systems. Their analytical identification and quantification suffers from a lack of knowledge of the general structure. Therefore sum- and group-parameters, such as dissolved organic carbon (DOC) or carboxylic groups, are of great importance for the characterization of humic substances and their reactivity. Humic/metal interactions can be determined under defined reaction conditions. Model experiments are helpful to confirm these results. Complexation capacities (CC) reflect the maximum of metal binding ability for the unit of HUS. The CC in respect to Cu(II) was determined by the titration of the initial amount of Cu(II) (10 μmol/l) with a HUS-solution of known DOC at a pH-value of 6.8. Differential pulse polarography with a dropping mercury electrode was used for detection. The results (2 to 7 μmol per mg DOC) suggest complex formation by oxygen containing functional groups in addition to nitrogen containing ones. Iron, strongly bound to HUS even at pH 2.2, shows some similarities to Fe(III) in hydroxamic acid compounds. Coordination of Hg(II) onto thio-groups of the humics can be confirmed by means of photochemical decomposition reactions using model ligands and natural samples. CCs for isolated humics suggest that in most natural aquatic systems there is an excess of organic ligand functions compared with the dissolved heavy metals. CCs, however, should only be discussed in close connection with the determination method applied and the reference metal concerned.
    Type of Medium: Electronic Resource
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  • 8
    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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  • 9
    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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  • 10
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Using gel filtration chromatography and high-sensitivity UV and organic carbon (OC) detection, the quality and quantity of organic matter in a stream (the Alb, Southern Germany) has been studied in the winter season. In the catchment area and upstream of two sewage plant effluents the organic load has been low (below 1 mg/l TOC) and has been dominated by humic substances (more than 80%). Downstream of the sewage plants, TOC increased up to 5 mg/l while humic constituents decreased down to 30%. A detailed analysis showed that in the catchment area the humic fraction has been composed of fulvic acids with relatively high amounts of aliphatic structures. Downstream of the sewage plants, the humic fraction has been composed of fulvic acid precursors with associated non-humic matter. It is concluded that the quality and quantity of organic constituents in the stream has been dominated by the secondary effluents.
    Type of Medium: Electronic Resource
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