Fulvic Acid

Fractionation

Historically, scientists have used variations of similar methods for extracting HS from NOM and separating the extracts into HA and FA. The International Humic Substances Society advocates using standard laboratory methods to prepare humic and fulvic acids. Humic substances are extracted from soil and other solid sources using 0.1 M NaOH, under a nitrogen atmosphere, to prevent abiotic oxidation of some of the components of HS. The HA is then precipitated at pH 1. The soluble fraction is treated on a resin column to separate fulvic acid components from other acid soluble compounds. The fraction of NOM not extracted by 0.1 NaOH is humin. Humic and fulvic acid are extracted from natural waters using a resin column after microfiltration and acidification to pH 2. The humic materials are eluted from the column with NaOH, and humic acid is precipitated at pH 1. After adjusting the pH to 2, fulvic acid is separated from other acid soluble compounds, using a resin column as with solid phase sources. An analytical method for quantifying humic acid and fulvic acid in commercial ores and humic products, has been developed based on the IHSS humic acid and fulvic acid preparation methods.