Date of Award
Master of Arts
Dr. Donald R. Schreiber
Dr. Michael E. McCarville
Dr. Subra Muralidharan
Masters Thesis-Open Access
Achard (1786) extracted peat with alkali and reported obtaining dark compounds now called humic substances. These are complex, high molecular weight, polyphenolic compounds naturally occurring in soil, in fresh-water and in marine environments. They are biodegradation products of plant materials.
The International Humic Substances Society (IHSS) adapted Achard's method to separate humic substances into three fractions: (1) humic acids (HA), soluble only at high pH; (2) fulvic acids (FA), water-soluble at any pH; and (3) humin, insoluble at any pH. The IHSS method involves contact of soil with 0.1N.NaOH solution, followed by acidification with HCl.
In this study, 0.01 N. solutions of benzenediols m 0.1 N.NaOH were prepared and mixed for 24 hours. The resulting mixtures were then adjusted to pH 7.0 with HCl. Fractions were isolated from these mixtures using Reverse-Phase Preparatory HPLC and freeze-drying. Insights on the structure of the products formed during the 24 hours contact were gained from FTIR, HPLC-MS and Proton-Nmr.
These studies prove that the alkali extraction step of the IHSS humic acid extraction process from soils has a definite potential for producing artifacts because of its polymerization effect on the model compounds studied.
Germay, Roger J., "A Qualitative Investigation of the Polymerization Process in the IHSS Humic Substances Extraction Procedure using Model Phenolic Compounds" (2001). Master's Theses. 4780.