The American Association Of Plant Food Chemist Officials (AAPFCO) has approved a method to determine the fulvic acid fraction of plant and soil amendments for the purposes of labeling.
A New Standardized Method for Quantification of Humic and Fulvic Acids in Humic Ores and Commercial Products
Humic Substance Label Claims for Agricultural Crop Production Consistent with AAPFCO Guidelines
If your fulvic acid product does not have the fulvic acid fraction quantified by this method, contact the manufacturer and urge them to do so.
Originally Posted by Lawrence Mayhew
"The analytical procedure developed jointly by the Humic Products Trade Association (HPTA) and the International Humic Substances Society (IHSS) has been approved by AAPFCO as the only officially recognized procedure for the analysis of humic acids and a specific category of fulvic acids. The procedure has been published in the Journal of AOAC International, a peer reviewed scientific journal, and is currently being reviewed by the International Organization for Standardization (ISO) as a possible international analytical standard."
Fulvic Acid Fraction - the portion of humic substances that are soluble in both alkali and acid aqueous solutions.
Hydrophobic Fulvic Acids - are the portions of humic substances that are soluble in both alkali and acidic aqueous solutions that are separated from non-humic aqueous substances in the fulvic acid fraction by selective adsorption onto a nonionic macroporous acrylic ester resin of moderate polarity i.e. DAX-8 resin, at low pH.
Humic Substances - the major organic constituents of soil organic matter and the aquatic environment, consisting of complex heterogeneous mixtures of carbon-based substances formed by biochemical reactions during the decay and transformation of plant and microbial remains. They are primarily composed of three main fractions, called humic acids, fulvic acids, and humin, which are operationally defined by their solubility in dilute alkali and acid solutions. High concentrations of humic substances are commercially harvested from terrestrial deposits of Leonardite, oxidized lignite, oxidized sub-bituminous coals, humalite, carbonaceous shales, peat, and sapropel.