IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 52 Analysis and Characterization Tuesday, 25 August 2026 / Hall B+C SL20 A Fluorescence Spectroscopy-Based Method for the Validation and Quantification of Fulvic Acids from Peat, Coal and Aquatic Sources and Claimed Fulvic Acid-Containing Products Richard T. Lamar1, Aletia James1, Adam Gilmore2 1 Huma, Inc., Gilbert, AZ, USA 85233, rich@huma.us 2 Horiba, Inc., Piscataway, NJ USA Fulvic acids (FA) are defined as the fraction of humic substances (HS) that are soluble in both alkaline and acidic aqueous solutions. They are found in soils, composts, sapropels, shilajits, peats and humate ores including brown coals, oxidized lignites (aka Leonardites) and oxidized sub bituminous coals. They are also included as constituents in many agricultural and nutraceutical products. Currently, FA are quantified using ISO Method 19822 “Fertilizers and soil conditioners — Determination of humic and hydrophobic fulvic acids concentrations in fertilizer materials” [1]. As the title indicates, this method only quantifies the “hydrophobic FA” fraction which is defined as that fraction which binds to a DAX-8 resin. However, the full FA fraction (FF) is what exists in source materials and products that are produced and sold. In addition, the manufacturer of the DAX-8 resin, Supelco, has discontinued offering the resin, rendering the method obsolete. Further, adulterants including lignosulfonates, molasses, corn steep liquors and organic acids are often sold as FA. A humate source validation method based on UV spectroscopy, has recently been published, but it does not quantify the FF [2]. In this report, we have investigated the development of a sequential combination validation to quantification method. The method first validates a FF as coming from a humic-based source and, then once confirmed applies a regression model to quantitate the FF. The method is based on the Aqualog (Horiba) spectrometer technology called A-TEEM (i.e absorbance-transmittance excitation emission matrix), which collects UV and fluorescent spectra simultaneously, and chemometric discrimination analysis for validation and regression analyses for quantification. The method was developed by obtaining verified FF samples from a wide variety of sources including humate ores (i.e. oxidized lignites) and sub bituminous coals, peats, and shilajits from different geographical locations; aquatic and soil FA IHSS standards and an IHSS aquatic FF standard; and a number of different agricultural and nutraceutical products claiming to either contain FA or consist of pure FA. Fulvic fractions were extracted from solid
RkJQdWJsaXNoZXIy NDA4Mjc=