HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Knicker, H. Articles by González-Vila, F.J. Search for Related Content PubMed PubMed Citation Articles by Knicker, H. Articles by González-Vila, F.J. Agricola Articles by Knicker, H. Articles by González-Vila, F.J. Related Collections Humic Substances Soil Methods/Instrumentation Soil Biochemistry

Article
SYMPOSIUM PAPERS

Formation of Heteroaromatic Nitrogen after Prolonged Humification of Vascular Plant Remains as Revealed by Nuclear Magnetic Resonance Spectroscopy

^a Lehrstuhl für Bodenkunde, Technische Universität München, 85350 Freising-Weihenstephan, Germany
^b Department of Chemistry, The Ohio State University, Columbus, OH 43210
^c Instituto de Recursos Naturales y Agrobiología, C.S.I.C., P.O. Box 1052, 41080 Sevilla, Spain

* Corresponding author (knicker{at}weihenstephan.de)

Received for publication June 26, 2000. In the search for the mechanisms involved in the immobilization of organic nitrogen in humified remains of vascular plants, the efforts of the present investigation were directed toward the examination of the transformation of nitrogenous compounds during the peat and coal stage by means of solid-state nuclear magnetic resonance (NMR) spectroscopy. While accumulation of heteroaromatic-N is not detected in most of the studied peat layers, a clear shoulder in the chemical shift region of pyrrole- or indole-N is observed in the solid-state ¹⁵N NMR spectrum of material from the deepest (and thus oldest) peat layer underlying the sapropel from Mangrove Lake, Bermuda (10000 years). This points to the assumption that transformation of nitrogen occurs between an advanced stage of peatification and an early stage of coalification. The observed sudden alteration in nitrogen functionality indicates that continuous accumulation of newly synthesized or selectively preserved biogenic structures is not responsible for the presence of heteroaromatic-N in these fossilized deposits. It seems rather likely that abiotic conditions, occurring during advanced sediment maturation, have an effect on the observed N transformation. With increasing coalification, pyrrole-type-N becomes the dominant form in the macromolecular coal network. Pyridine-type-N was only detected in a coal of anthracite rank.

Abbreviations: CPMAS, cross polarization magic angle spinning • NMR, nuclear magnetic resonance