Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Language: English
    In: Chemosphere, 2008, Vol.71(5), pp.954-960
    Description: We present a new analytical procedure for the extraction and determination of natural estrogens in soils based on pressurised liquid extraction and GC–MS determination. After testing twelve solvents, acetone proved to be the most efficient extractant. The optimum extraction temperature is 60 °C. Soil extracts have to be purified and concentrated by C-18 solid phase extraction. The dried extracts are derivatised by -methyl- -(trimethylsilyl)trifluoro-acetamide before measurement by GC–MS. Recoveries of 79–103% with relative standard deviations ⩽13% document reliability of this method. Further, rapidity of extraction and a low detection limit (1 ng kg ) represent an improvement of estrogen analysis in soils compared to established procedures.
    Keywords: Steroids ; Pressurized Liquid Extraction (Ple) ; Accelerated Solvent Extraction (Ase) ; Agricultural Soil ; Soil Extraction ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Chemosphere, 1990, Vol.21(12), pp.1397-1410
    Description: The sorptive behavior of the experimental herbicide quinmerac (7-chloro-3-methyl-quinoline-8-carboxylic acid) was investigated in soils of different organic carbon content. Distribution coefficients are low (K d = 0.03 - 12 mL g −1 ) and are mainly determined by the soil organic carbon content. The adsorption mechanism operating in neutral to slightly acid agricultural soils is supposed to be cation bridging with the anionic form of quinmerac. Under acid conditions (pH 〈 5.2) the predominating sorption mechanism is hydrophobic interaction. Therefore soil pH and cationic composition are also major factors determining the sorptive capacity of soils for quinmerac. Adsorption kinetics, equilibrium adsorption and desorption isotherms were determined in batch experiments. Sorption kinetics were investigated at various times from 15 min to 96 hours. A two-step sorption behavior with time was found for the anionic form indicating two types of sorption mechanisms or sorption sites. Equilibrium for the first type was reached at a time-scale of minutes and for the second type after 24 hours. Adsorption isotherms were determined for two soil/solution ratios 1 5 and 1 3 . Alteration of the adsorbent concentration exerted a strong influence on the adsorption isotherms. An increase of sorption was found with increasing adsorbent concentration. Under natural soil conditions sorption is therefore expected to be higher compared to the batch experiments. Desorption isotherms were obtained using the consecutive desorption method. Desorption hysteresis was not observed which indicates weak interactions. Implications of the results for the movement of quinmerac under field conditions and for models describing transport are discussed.
    Keywords: Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Chemosphere, 1998, Vol.36(1), pp.79-97
    Description: Dissolved organic matter (DOM) in the soil solution or groundwater can have a considerable effect on the dissipation of hydrophobic organic pollutants. We used the fluorescence quenching technique as well as the reversed-phase separation technique to determine the partition coefficient of 3- to 5-ring PAH to dissolved organic matter from agricultural soils and forest floor materials. Several techniques (centrifugation, pressure filtration, and percolation) are compared for obtaining DOM solution most representative of the DOM in the natural soil solution to use for the sorption experiments. Centrifugation was shown to be the most suitable procedure to obtain DOM solutions in large quantities with a composition most similar to the field soil solution. PAH binding to DOM from mineral soil was found to be considerably lower compared to DOM from acid forest floor materials. These differences can partly be explained by compositional differences with respect to hydrophobic and hydrophilic components of DOM. Binding capacity of DOM was only slightly affected by changes in pH and electrical conductivity of the soil solution. The partition coefficients for DOM from soils are rather different to the data given for model DOM solutions, such as humic acids, fulvic acids, or Aldrich humic acid. To obtain realistic estimates for the effect of DOM on the mobility of hydrophobic organic chemicals in soils, it is essential to use DOM solutions representative of the dissolved organic matter in the soil solution.
    Keywords: Pah ; DOM ; Doc ; Fluorescence Quenching ; Reversed-Phase Separation ; Soil Solution ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages