Naturwissenschaften

, Volume 89, Issue 2, pp 84–88

Molecular structures and associations of humic substances in the terrestrial environment

  • André J. Simpson
  • William L. Kingery
  • Michael H. Hayes
  • Manfred Spraul
  • Eberhard Humpfer
  • Peter Dvortsak
  • Rainer Kerssebaum
  • Markus Godejohann
  • Martin Hofmann
Short Communication

DOI: 10.1007/s00114-001-0293-8

Cite this article as:
Simpson, A.J., Kingery, W.L., Hayes, M.H. et al. Naturwissenschaften (2002) 89: 84. doi:10.1007/s00114-001-0293-8

Abstract

Here we show, for the first time, evidence of the primary molecular structures in humic substances (HS), the most abundant naturally occurring organic molecules on Earth, and their associations as mixtures in terrestrial systems. Multi-dimensional nuclear magnetic resonance (NMR) experiments show us that the major molecular structural components in the mixtures operationally defined as HS are aliphatic acids, ethers, esters and alcohols; aromatic lignin derived fragments; polysaccharides and polypeptides. By means of diffusion ordered spectroscopy, distinct diffusion coefficients consistent with relatively low molecular weight molecules were observed for all the components in the mixtures, and saccharides were the largest single class of component present. Liquid chromatography NMR confirmed that HS components can be easily separated and nuclear Overhauser effect (NOE) enhancements support the finding that the components are of relatively low molecular weight <~2,000 Da. The widely recognized properties of HS, i.e., characteristics indicative of crosslinked, macromolecular networks, can now be explained as aggregation of mixtures, most likely instigated by complexation with metal cations.

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • André J. Simpson
    • 1
  • William L. Kingery
    • 2
  • Michael H. Hayes
    • 3
  • Manfred Spraul
    • 4
  • Eberhard Humpfer
    • 4
  • Peter Dvortsak
    • 4
  • Rainer Kerssebaum
    • 4
  • Markus Godejohann
    • 4
  • Martin Hofmann
    • 4
  1. 1.Department of Chemistry, Ohio State University, 120 West 18th Avenue, Box 67, Columbus, OH 43210USA
  2. 2.Department of Plant and Soil Sciences, Mississippi State University, Box 9555, MS 39762USA
  3. 3.Department of Chemical and Environmental Sciences, University of Limerick, LimerickIreland
  4. 4.Bruker Analytik, Silberstreifen, 76287 RheinstettenGermany