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Ammonia fixation by humic substances: A nitrogen-15 and carbon-13 NMR study

Science of Total Environment

By:
and
https://doi.org/10.1016/0048-9697(92)90017-M

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Abstract

The process of ammonia fixation has been studied in three well characterized and structurally diverse fulvic and humic acid samples. The Suwannee River fulvic acid, and the IHSS peat and leonardite humic acids, were reacted with 15N-labelled ammonium hydroxide, and analyzed by liquid phase 15N NMR spectrometry. Elemental analyses and liquid phase 13C NMR spectra also were recorded on the samples before and after reaction with ammonium hydroxide. The largest increase in percent nitrogen occurred with the Suwannee River fulvic acid, which had a nitrogen content of 0.88% before fixation and 3.17% after fixation. The 15N NMR spectra revealed that ammonia reacted similarly with all three samples, indicating that the functional groups which react with ammonia exist in structural configurations common to all three samples. The majority of nitrogcn incorporated into the samples appears to be in the form of indole and pyrrole nitrogen, followed by pyridine, pyrazine, amide and aminohydroquinone nitrogen. Chemical changes in the individual samples upon fixation could not be discerned from the 13C NMR spectra.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Ammonia fixation by humic substances: A nitrogen-15 and carbon-13 NMR study
Series title:
Science of Total Environment
DOI:
10.1016/0048-9697(92)90017-M
Volume:
113
Issue:
1-2
Year Published:
1992
Language:
English
Publisher:
Elsevier
Contributing office(s):
Toxic Substances Hydrology Program
Description:
21 p.
First page:
67
Last page:
87