P90-MO CHARACTERISATION OF ANTARCTIC FULVIC ACIDS BY A NOVEL AND SELECTIVE CHEMICAL REDUCTION – IMPLICATIONS FOR THE IDENTIFICATION OF PRECURSORS OF HUMIC SUBSTANCES

• Main Authors: Rama D. Nimmagadda, Christopher R. Mcrae
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Suwannee River; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.494.144; http://www.imog2007.org/files/Monday Posters/Monday Posters Organic matter composition/P90-MO Nimmagadda.pdf

The complex supramolecular nature of fulvic acids (FA) can be attributed to the high abundance of carboxylic acids, phenols and hydroxyl functional groups present in their structures. The abundance of these polar functional groups also contributes to difficulties faced when analysing FA. Although various FA characterisation techniques have been reported (Abbt-Braun et al., 2004), no single technique or combinations of techniques have been completely successful in the structural elucidation of fulvic acid. The novel reduction technique used in this study enables the reduction of polycarboxylic acids to their corresponding methyl groups using n-butylsilane/tris (pentafluorophenyl) borane in a one-pot reaction (Nimmagadda and McRae, 2006a). The reduction of polycarboxylic acids to their hydrocarbon equivalents offers the potential for the transformation of supramolecular fulvic acid into simpler ‘backbone ’ structures amenable to characterisation using GC and GC-MS. Similarly, aldehydes, ketones, primary, secondary and tertiary alcohols are reduced into their corresponding methyl functions (Nimmagadda and McRae, 2006b). Phenols and polyphenols are reduced to silylethers. ‘Backbone ’ structures of standard fulvic acids such as Suwannee River fulvic acid