Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: October 21, 2001
Citation: NICHOLS, K.A., WRIGHT, S.E., SCHMIDT, W.F., SIMPSON, A.J., DZANTOR, E.K. USING NMR TO DISTINGUISH UNIQUE COMPONENTS OF HUMIC SUBSTANCES. AMERICAN SOCIETY OF AGRONOMY MEETINGS. 2001. S03-NICHOLS190155-0.
Humic substances (humic acid, fulvic acid and humin) are extensively studied fractions of soil organic matter (SOM). Recently, a new fraction of SOM, glomalin, has been identified. Humic substances are complex mixtures of biopolymers, polysaccharides, proteins, and metals while glomalin is a glycoprotein produced on the hyphae of arbuscular mycorrhizal fungi. NMR spectroscopy has been used widely to determine the 3D structure of small biomolecules. As technology has progressed, the composition of larger and more complex molecules is being determined using 1H and 13C NMR spectroscopy. Glomalin and humic acid (HA) have similar solubility and physical characteristics and cannot be readily distinguished from each other. Both glomalin and HA were chemically extracted from eight soils from MD (Baltimore series), NE (Wymore and Pawnee series), CO (Haxtun and Sampson series) and GA (Pacolet and Cecil series) and compared using 1H NMR spectroscopy. The 1D 1H NMR spectra showed that glomalin and HA are compositionally unique molecules. NMR spectroscopy provides a fast, accurate and nondestructive method to compare small amounts of compounds that may have similar characteristics but unique structures.