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@ARTICLE{Berns:45074,
      author       = {Berns, A. and Vinken, R. and Bertmer, M. and Breitschwerdt,
                      A. and Schäffer, A.},
      title        = {{U}se of 15{N}-depleted artificial compost in bound residue
                      studies},
      journal      = {Chemosphere},
      volume       = {59},
      issn         = {0045-6535},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {PreJuSER-45074},
      pages        = {649 - 658},
      year         = {2005},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {Association of bound residues to soil humic matter may be
                      accomplished by different binding mechanisms such as
                      sequestration in hydrophobic interiors of the organic
                      material or covalent linkage to the organic matter. The
                      structures and chemical environments of compounds can be
                      observed by NMR spectroscopy. We applied 15N-NMR
                      spectroscopy to study the soil-bound residues of 15N-labeled
                      simazine. As the 15N-isotope has a low sensitivity and
                      natural abundance 15N-NMR experiments require long
                      measurement times and often result in low signal-to-noise
                      (S/N) ratios. Therefore, in addition to the use of
                      15N-labeled simazine, 15N-depleted compost was used to
                      reduce the amount of background signal and enhance the
                      sensitivity. The compost was produced from maize and wheat
                      plants grown on sand with 15N-depleted NH4NO3 as sole
                      nitrogen source. The plants were freeze-dried, ground and
                      mixed with sand for composting. After a composting period of
                      224 days analysis of the compost revealed a 15N-content of
                      267 ppm as opposed to a natural abundance of 3650 ppm.
                      Characterization of this artificial compost produced
                      parameter values similar to those of a natural compost. The
                      13C-NMR-spectra of the humic and fulvic acids during
                      different stages of maturity showed that there was a shift
                      from single-bond functional groups to more complex
                      double-bond and aromatic structures. Experiments with this
                      compost showed an increased signal intensity. The improved
                      sensitivity made it possible to obtain interpretable NMR
                      signals in contrast to experiments with 15N-simazine on
                      native soil where no signals were detectable. The data
                      indicated that the bound residues of simazine are composed
                      of metabolites resulting from N-dealkylation and triazine
                      ring destruction. Silylation of the bound residues showed a
                      very strong binding of the residues to the matrix as only a
                      small fraction could be solubilized.},
      keywords     = {Chromatography, Gel / Humic Substances: analysis / Magnetic
                      Resonance Spectroscopy: methods / Nitrogen Isotopes /
                      Pesticide Residues: chemistry / Simazine: chemistry / Soil:
                      analysis / Trimethylsilyl Compounds / Humic Substances (NLM
                      Chemicals) / Nitrogen Isotopes (NLM Chemicals) / Pesticide
                      Residues (NLM Chemicals) / Soil (NLM Chemicals) /
                      Trimethylsilyl Compounds (NLM Chemicals) / Simazine (NLM
                      Chemicals) / trimethylchlorosilane (NLM Chemicals) / J
                      (WoSType)},
      cin          = {ICG-IV},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)VDB50},
      pnm          = {Chemie und Dynamik der Geo-Biosphäre},
      pid          = {G:(DE-Juel1)FUEK257},
      shelfmark    = {Environmental Sciences},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:15792662},
      UT           = {WOS:000228890400007},
      doi          = {10.1016/j.chemosphere.2004.10.027},
      url          = {https://juser.fz-juelich.de/record/45074},
}